CN1737673A - Substrate for liquid crystal display and liquid crystal display device having same - Google Patents

Abstract

The invention relates to a substrate for a liquid crystal display used in a display section of an information apparatus and a liquid crystal display having the same and provides a substrate for a liquid crystal display and a liquid crystal display having the same that provide good display characteristics without any increase in manufacturing steps. A configuration is employed which includes a plurality of gate bus lines (12)formed on a substrate substantially in parallel with each other, a plurality of drain bus lines (14) formed on the substrate such that they intersect the gate bus lines (12) with an insulation film interposed therebetween, pixel regions provided on the substrate in the form of a matrix, pixel electrodes (16) having a plurality of electrode units (26) formed in the pixel regions, slits (34) formed between the electrode units, and connection electrodes (36) for connecting the plurality of electrode units with each other and a thin film transistor (10) formed at each pixel region.

Description

Substrate for liquid crystal display and liquid crystal display device having same

This application is a divisional application of an invention patent application with a filing date of April 15, 2003, an application number of 03109896.7, and an invention title of "Substrate for Liquid Crystal Display and Liquid Crystal Display Device with the Substrate".

technical field

The present invention relates to a liquid crystal display substrate used in a display portion of information equipment and the like, and a liquid crystal display device having the same.

Background technique

In recent years, active-matrix liquid crystal display devices with thin-film transistors (TFT: Thin Film Transistor) in each pixel are developing toward larger size, higher grayscale display, and higher contrast ratio.

FIG. 70 is a schematic structural view of a pixel of a TFT substrate of an active matrix liquid crystal display device. As shown in FIG. 70 , on the TFT substrate, a plurality of gate bus lines 112 (only two are shown in FIG. 70 ) extending in the left-right direction in the figure and substantially parallel to each other are formed. A plurality of drain bus lines 114 (only two are shown in FIG. 70 ) that cross the gate bus lines 112 through an insulating film not shown and extend in the vertical direction in the figure and are substantially parallel to each other are formed. The area surrounded by the drain bus line 112 and the drain bus line 114 forms a pixel area. A pixel electrode 116 is formed in the pixel area. In addition, a storage capacitor bus line 118 extending substantially parallel to the gate bus line 112 is formed across approximately the center of the pixel area.

TFT 110 is formed near the intersection of gate bus line 112 and drain bus line 114 . The drain 122 of the TFT 110 is led out from the drain bus line 114 and is formed on one end side of the operational semiconductor layer formed on the gate bus line 112 and a channel protection film (both not shown) formed thereon. On the other hand, the source 124 of the TFT 110 is disposed opposite to the drain 122 with a predetermined gap, and is formed on the other end side of the operating semiconductor layer and the channel protection film. The region directly under the channel protective film of the gate bus line 112 functions as a gate of the TFT 110 . In addition, the source electrode 124 is electrically connected to the pixel electrode 116 through a contact hole (not shown in the figure).

FIG. 71 shows the alignment state of liquid crystal molecules in a VA (Vertically Aligned Vertically Aligned) mode liquid crystal display device fabricated using the TFT substrate shown in FIG. 70 . Arrows in the figure indicate the inclination directions of the liquid crystal molecules when a voltage is applied to the liquid crystal layer. In FIG. 71, three pixels defined by a light-shielding film (BM; Black Matrix) 140 are shown. As shown in FIG. 71 , in a VA-mode liquid crystal display device in which the orientation film is not subjected to an orientation treatment such as rubbing, when a voltage is applied, the liquid crystal molecules tilt in various directions. As a result, alignment regions having different areas are formed in each pixel. In addition, the boundary line (disclination) of the orientation area of each pixel can be seen as a dark line 142 arranged differently in each pixel. Therefore, especially when the display screen is viewed from an oblique direction, color spots, roughness (ざらつき), residual images, etc. may be seen on the display screen, and the display quality is greatly reduced.

The liquid crystal display device can be used as a monitor of a personal computer (PC) or a television receiver. In such an application, it is necessary to perform a wide viewing angle so that the liquid crystal display device can be viewed from various directions.

An MVA (Multi-Domain Vertical Alignment) type liquid crystal display device (hereinafter abbreviated as MVA-LCD) has already been proposed as a technique for widening the viewing angle (for example, refer to Patent Document 1).

72A and 72B show schematic cross-sectional structural views of the MVA-LCD. FIG. 72A shows a state where no voltage is applied to the liquid crystal layer, and FIG. 72B shows a state where a predetermined voltage is applied to the liquid crystal layer. As shown in FIGS. 72A and 72B , the MVA-LCD has two substrates 302 , 304 arranged opposite to each other. Transparent electrodes (not shown in the figure) are formed on the two substrates 302 and 304 . Further, on one of the substrates 302, a plurality of linear protrusions (banks) 306 made of resin or the like are formed parallel to each other, and on the other substrate 304, a plurality of linear protrusions 308 are formed parallel to each other. Viewed from a direction perpendicular to the substrate surface, the protrusions 306, 308 are alternately arranged.

Between the two substrates 302, 304, liquid crystal 160 having negative dielectric anisotropy is sealed. As shown in FIG. 72A, liquid crystal molecules 312 are oriented substantially perpendicular to the substrate surfaces due to the orientation restricting force of vertical alignment films (not shown) formed on the opposing surfaces of the two substrates 302, 304. The liquid crystal molecules 312 in the vicinity of the protrusions 306 , 308 are oriented substantially perpendicular to the slope formed by the protrusions 306 , 308 . That is, the liquid crystal molecules 312 near the protrusions 306 and 308 are oriented obliquely with respect to the substrate surface.

As shown in FIG. 72B , when a predetermined voltage is applied between the transparent electrodes of the substrates 302 and 304 , the liquid crystal molecules 312 near the protrusions 306 and 308 tilt in a direction perpendicular to the direction in which the protrusions 306 and 308 extend. This inclination is propagated to each liquid crystal molecule 312 between the protrusions 306 and 308, and the liquid crystal molecules 312 in the region between the protrusions 306 and 308 are inclined in the same direction.

Thus, by arranging the protrusions 306, 308, etc., the inclination direction of the liquid crystal molecules 312 in each region can be restricted. When the protrusions 306 and 308 are formed in two directions substantially perpendicular to each other, the liquid crystal molecules 312 are inclined in four directions within one pixel. As a result of the mixture of viewing angle characteristics of each region, in MVA-LCD, a wide viewing angle can be obtained when displaying white or black. In MVA-LCD, even when the angle between the direction perpendicular to the display screen and the up, down, left, and right directions is 80°, a contrast ratio of 10 or higher can be obtained.

References to prior art include:

[Patent Document 1] Patent No. 2947350,

[Patent Document 2] JP-A-2000-305100,

[Patent Document 3] JP-A-2001-249340,

[Patent Document 4] JP-A-2001--249350 Gazette,

[Patent Document 5] JP-A-2002-40432,

[Patent Document 6] JP-A-2002-40457,

[Patent Document 7] JP-A-2000-47251.

However, in the MVA-LCD shown in FIG. 72A and FIG. 72B , since additional steps for forming 306 and 308 are required, there are problems in that the manufacturing yield decreases and the manufacturing cost increases.

In addition, there is a method of forming the removed portion (slit) of the transparent electrode instead of the protrusions 306 and 308 . However, when a slit is formed on the common electrode on the CF substrate, the exposed CF layer is in contact with the liquid crystal layer. For example, when a resin in which a pigment is dispersed as a color component is used for the CF layer, there arises a problem that the inorganic component of the pigment may contaminate the liquid crystal layer and the semiconductor layer.

Fig. 73 shows another structure of the TFT substrate of the MVA-LCD. As shown in FIG. 73 , the pixel electrode 116 has a main portion 128 extending substantially parallel to or perpendicular to the two bus lines 112, 114, a branch portion 130 branching from the main portion 128 and extending in an oblique direction, and a gap between adjacent branch portions 130. Interval 132. In the MVA-LCD manufactured using the TFT substrate shown in FIG. 73, the alignment direction of the liquid crystal molecules is determined by the trunk portion 128 and the branch portion 130.

However, in the MVA-LCD fabricated with the TFT substrate shown in FIG. 73 , since the response time of the liquid crystal molecules is very long, singular points of the orientation vectors of the liquid crystal molecules are randomly generated on the branch portion 130 . So the singularity moves every pixel or every frame. Therefore, especially when the display screen is viewed from an oblique direction, color spots or roughness are seen, resulting in a problem that the display quality deteriorates.

Contents of the invention

An object of the present invention is to provide a substrate for a liquid crystal display device capable of obtaining good display quality without increasing the number of manufacturing steps, and a liquid crystal display device having the substrate.

The above objects are achieved by employing a substrate for a liquid crystal display device having the following characteristics: the substrate has: an insulating substrate sandwiching liquid crystal together with a counter substrate; and a plurality of gate bus lines formed on the insulating substrate and substantially parallel to each other; a plurality of drain bus lines, which intersect with the gate bus lines through an insulating film; pixel regions, which are arranged in a matrix on the insulating substrate; pixel electrodes, which have: a plurality of electrode units, The electrode unit has a plurality of trunk parts, a plurality of branch parts branched from the trunk part, and spaces between the branch parts, and is formed in the pixel region; a narrow gap formed between the electrode units a slit; and a connection electrode connecting the plurality of electrode units to each other; a thin film transistor formed in each of the pixel regions.

Description of drawings

FIG. 1 is a schematic diagram showing a schematic configuration of a liquid crystal display device according to Example 1-1 of the first embodiment of the present invention.

2 is a schematic diagram showing an equivalent circuit of a liquid crystal display device according to Example 1-1 of the first embodiment of the present invention.

3 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 1-1 of the first embodiment of the present invention.

4 is a schematic configuration diagram showing a liquid crystal display device according to Example 1-1 of the first embodiment of the present invention.

5 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 1-2 of the first embodiment of the present invention.

6 is a schematic view showing a modified example of the structure of the substrate for a liquid crystal display device according to Example 1-2 of the first embodiment of the present invention.

7 is a schematic view showing another modified example of the structure of the substrate for a liquid crystal display device according to Example 1-2 of the first embodiment of the present invention.

8 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 1-3 of the first embodiment of the present invention.

9 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 1-4 of the first embodiment of the present invention.

10 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 1-5 of the first embodiment of the present invention.

11 is a schematic view showing a modification example of the structure of the substrate for a liquid crystal display device according to Example 1-5 of the first embodiment of the present invention.

12 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 1-6 of the first embodiment of the present invention.

13 is a schematic view showing a modification example of the structure of the substrate for a liquid crystal display device according to Example 1-6 of the first embodiment of the present invention.

14 is a schematic cross-sectional view showing a modified example of the structure of the substrate for a liquid crystal display device according to Example 1-6 of the first embodiment of the present invention.

15 is a schematic cross-sectional view showing another modified example of the structure of the substrate for a liquid crystal display device according to Example 1-6 of the first embodiment of the present invention.

FIG. 16 is a schematic diagram showing a structural example of a substrate for a liquid crystal display device according to this embodiment.

FIG. 17 is a schematic diagram showing a structural example of a substrate for a liquid crystal display device according to this embodiment.

FIG. 18 is a schematic diagram showing a structural example of a substrate for a liquid crystal display device according to this embodiment.

19 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 2-1 of the second embodiment of the present invention.

20 is a schematic view showing the alignment state and display state of liquid crystal molecules of the substrate for a liquid crystal display device according to Example 2-1 of the second embodiment of the present invention.

21 is a schematic view showing the orientation state and display state of liquid crystal molecules of the substrate for a liquid crystal display device according to Example 2-1 of the second embodiment of the present invention.

22A to 22H are schematic diagrams showing structural modifications of the substrate for a liquid crystal display device according to Example 2-1 of the second embodiment of the present invention.

23A to 23C are schematic views showing structural modifications of the substrate for a liquid crystal display device according to Example 2-1 of the second embodiment of the present invention.

24A to 24C are schematic diagrams showing structural modifications of the substrate for a liquid crystal display device according to Example 2-1 of the second embodiment of the present invention.

25A to 25B are schematic views showing structural modifications of the substrate for a liquid crystal display device according to Example 2-1 of the second embodiment of the present invention.

26A to 26D are schematic diagrams showing structural modifications of the substrate for a liquid crystal display device according to Example 2-1 of the second embodiment of the present invention.

27 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 2-2 of the second embodiment of the present invention.

28 is a schematic view showing the orientation state and display state of liquid crystal molecules of the substrate for a liquid crystal display device according to Example 2-2 of the second embodiment of the present invention.

29 is a schematic view showing the orientation state and display state of liquid crystal molecules of the substrate for a liquid crystal display device according to Example 2-2 of the second embodiment of the present invention.

30 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 2-2 of the second embodiment of the present invention.

31 is a schematic view showing the orientation state and display state of liquid crystal molecules of the substrate for a liquid crystal display device according to Example 2-2 of the second embodiment of the present invention.

32 is a schematic view showing the alignment state and display state of liquid crystal molecules of the substrate for a liquid crystal display device according to Example 2-2 of the second embodiment of the present invention.

33A to 33D are schematic diagrams showing the alignment state of liquid crystal molecules and the display state of the liquid crystal display device as a prerequisite for a substrate for a liquid crystal display device according to a third embodiment of the present invention.

34A to 34C are schematic diagrams showing the structure of a substrate for a liquid crystal display device according to a third embodiment of the present invention.

35A to 35B are schematic diagrams showing the structure of a substrate for a liquid crystal display device according to a third embodiment of the present invention.

36A to 36C are schematic diagrams illustrating the structure of a substrate for a liquid crystal display device according to Example 3-1 of the third embodiment of the present invention.

37A to 37C are schematic diagrams showing the structure of a substrate for a liquid crystal display device according to Example 3-2 of the third embodiment of the present invention.

38 is a schematic diagram showing a specific structure of a substrate for a liquid crystal display device according to Example 3-2 of the third embodiment of the present invention.

39 is a schematic view showing a modified example of the structure of the substrate for a liquid crystal display device according to Example 3-2 of the third embodiment of the present invention.

40A to 40C are schematic diagrams showing the structure of a substrate for a liquid crystal display device according to Example 3-3 of the third embodiment of the present invention.

41A to 41C are schematic diagrams showing the structure of a substrate for a liquid crystal display device according to Example 3-4 of the third embodiment of the present invention.

42A to 42B are schematic configuration diagrams showing a substrate for a liquid crystal display device according to Example 3-5 of the third embodiment of the present invention.

43A to 43C are schematic diagrams showing the structure of a substrate for a liquid crystal display device according to Example 3-6 of the third embodiment of the present invention.

44A to 44C are schematic diagrams showing the structure of a substrate for a liquid crystal display device according to Example 3-7 of the third embodiment of the present invention.

45A to 45C are schematic cross-sectional views showing the structure of a substrate for a liquid crystal display device according to Example 3-8 of the third embodiment of the present invention.

46A to 46D are schematic configuration diagrams showing a substrate for a liquid crystal display device according to Example 3-8 of the third embodiment of the present invention.

47A to 47C are schematic configuration diagrams showing a substrate for a liquid crystal display device according to Example 3-9 of the third embodiment of the present invention.

48 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 3-10 of the third embodiment of the present invention.

49A to 49B are schematic diagrams showing the structure of a substrate for a liquid crystal display device according to Example 3-11 of the third embodiment of the present invention.

50A to 50B are schematic configuration diagrams showing a substrate for a liquid crystal display device according to Example 3-11 of the third embodiment of the present invention.

51A to 51G are schematic diagrams showing specific structural examples of a substrate for a liquid crystal display device according to Example 3-11 of the third embodiment of the present invention.

52A to 52B are explanatory views showing a substrate for a liquid crystal display device according to a fourth embodiment of the present invention.

53 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 4-1 of the fourth embodiment of the present invention.

54 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 4-1 of the fourth embodiment of the present invention.

55 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 4-2 of the fourth embodiment of the present invention.

56 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 4-3 of the fourth embodiment of the present invention.

57A to 57B are schematic configuration diagrams showing a substrate for a liquid crystal display device according to Example 4-4 of the fourth embodiment of the present invention.

58 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 4-4 of the fourth embodiment of the present invention.

59 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 4-5 of the fourth embodiment of the present invention.

60 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 4-5 of the fourth embodiment of the present invention.

61 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 5-1 of the fifth embodiment of the present invention.

62 is a schematic cross-sectional view showing the structure of a substrate for a liquid crystal display device according to Example 5-1 of the fifth embodiment of the present invention.

63A to 63B are schematic cross-sectional views showing a comparative example of the structure of a substrate for a liquid crystal display device according to Example 5-1 of the fifth embodiment of the present invention.

64 is a schematic cross-sectional view showing the structure of a substrate for a liquid crystal display device according to Example 5-2 of the fifth embodiment of the present invention.

65A to 65D are process cross-sectional schematic views showing a method of manufacturing a substrate for a liquid crystal display device according to Example 5-2 of the fifth embodiment of the present invention.

66A to 66C are process cross-sectional schematic views showing a method of manufacturing a substrate for a liquid crystal display device according to Example 5-2 of the fifth embodiment of the present invention.

67A to 67C are process cross-sectional schematic views showing a method of manufacturing a substrate for a liquid crystal display device according to Example 5-2 of the fifth embodiment of the present invention.

68 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 5-3 of the fifth embodiment of the present invention.

69 is a schematic diagram showing the structure of a substrate for a liquid crystal display device according to Example 5-4 of the fifth embodiment of the present invention.

Fig. 70 is a schematic diagram showing the structure of one pixel of a conventional liquid crystal display device substrate.

Fig. 71 is a schematic diagram showing the alignment state and display state of liquid crystal molecules in a conventional liquid crystal display device.

72A to 72B are schematic cross-sectional views showing the schematic structure of the MVA-LCD.

Fig. 73 is a schematic diagram showing a schematic structure of a TFT substrate of an MVA-LCD.

Detailed ways

(first embodiment)

The substrate for liquid crystal display and the liquid crystal display device having the substrate according to the first embodiment of the present invention will be specifically described using Examples 1-1 to 1-6.

(Example 1-1)

First, a substrate for a liquid crystal display according to Example 1-1 of this embodiment and a liquid crystal display device having the substrate will be described with reference to FIGS. 1 to 4 . FIG. 1 shows a schematic configuration of a liquid crystal display device according to this embodiment. The liquid crystal display device has a structure in which a TFT substrate (insulating substrate) 2 on which TFTs and the like are formed and a CF substrate (insulating counter substrate) 4 on which CFs and the like are formed are faced and pasted, and a substrate is sealed between the two substrates 2 and 4. liquid crystal.

FIG. 2 shows a schematic diagram of an equivalent circuit of elements formed on the TFT substrate 2 . On the TFT substrate 2, a plurality of gate bus lines 12 extending in the horizontal direction in the figure and parallel to each other are formed. A plurality of parallel drain bus lines 14 extending vertically in the drawing and crossing the gate bus lines 12 through an insulating film are formed. Each area surrounded by a plurality of gate bus lines 12 and drain bus lines 14 forms a pixel area. In each pixel region arranged in a matrix, TFTs 10 and pixel electrodes 16 are formed. The drain of each TFT 10 is connected to the adjacent drain bus line 14 , the gate is connected to the adjacent gate bus line 12 , and the source is connected to the pixel electrode 16 . At the center of each pixel electrode, a storage capacitor bus line 18 parallel to the gate bus line 12 is formed. These TFTs 10, pixel electrodes 16, and bus lines 12, 14, 16 are formed by a photolithography process by repeating a series of semiconductor processes of "film formation→resist coating→exposure→development→etching→resist stripping". Forming.

Returning to Fig. 1, the TFT substrate 2 is provided with: a gate bus driver circuit 80, which is equipped with driver ICs for driving a plurality of gate bus lines 12; a drain bus driver circuit 81, which is equipped with a driver IC for driving a plurality of drain electrodes Driver IC for bus 14. The drive circuits 80 and 81 output scan signals and data signals to predetermined gate bus lines 12 or drain bus lines 14 in accordance with predetermined signals output from the control circuit 82 . A polarizing plate 83 is disposed on the surface of the TFT substrate 2 opposite to the element formation surface, and a backlight member 85 is mounted on the surface of the polarizing plate 83 opposite to the TFT substrate 2 . On the other hand, a polarizing plate 84 is attached to the surface of the CF substrate 4 opposite to the CF formation surface.

FIG. 3 shows the structure of one pixel of the TFT substrate 2 . As shown in FIG. 3 , on the TFT substrate 2 , a plurality of (two are shown in FIG. 3 ) gate bus lines 12 extending in the left-right direction in the figure are formed, and they are parallel to each other with an interval of, for example, 300 μm. A plurality of (two are shown in FIG. 3 ) drain bus lines 14 extending vertically in the figure, intersecting the gate bus lines 12 substantially perpendicularly through an insulating film not shown, are formed parallel to each other at intervals of, for example, 100 μm. A region surrounded by a plurality of gate bus lines 12 and drain bus lines 14 forms a pixel region. Across the approximately central position of the pixel area, a storage capacitor bus line 18 extending substantially parallel to the gate bus line 12 is formed. On the storage capacitor bus 18, a storage capacitor electrode 20 is formed per pixel.

The TFT 10 is formed near the intersection of the gate bus line 12 and the drain bus line 14 . The drain 22 of the TFT 10 is led out from the drain bus line 14 and is formed on the drain bus line 12 at one end side of the active semiconductor layer and the channel protection film (both not shown) formed thereon. On the other hand, the source electrode 24 of the TFT 10 faces the drain electrode 22 through a predetermined gap, and is formed on the other end side of the operating semiconductor layer and the channel protection film. The region directly under the channel protection film of the gate bus line 12 functions as a gate of the TFT 10 .

In the pixel region, a pixel electrode 16 made of a transparent conductive film such as ITO (Indium Tin Oxide) is formed. The pixel electrode 16 has a rectangular outer periphery, and it has: a plurality of electrode units 26 smaller than the pixel area; electrode removal portions (slits) 34 formed between adjacent electrode units 26; The cells 26 are electrically connected to each other by connecting electrodes 36 . In FIG. 3 , three (a total of six) electrode units 26 are arranged vertically in the figure across the storage capacitor bus 18 .

The electrode unit 26 has a cross-shaped electrode (trunk portion) 28 extending substantially parallel to or perpendicular to the gate bus line 12 and the drain bus line 14 . In addition, the electrode unit 26 has a plurality of electrodes (branches) 30 branched from the main body 28 and extending in a comb shape inclined relative to the main body 28 ; there are electrode removal parts (spaces) 32 between adjacent branch parts 30 . The electrode unit 26 is divided into four orientation regions having substantially the same area by the trunk portion 28 . The four arrows in the electrode unit 26 indicate the tilt direction of the liquid crystal molecules (the direction in which the liquid crystal molecules are tilted on the CF substrate 4 side). The liquid crystal molecules at the time of voltage application are substantially parallel to the branch portion 30 and inclined toward the trunk portion 28 .

The width Wg of the electrode unit 26 parallel to the direction of the gate bus line 12 is, for example, 77 μm. The width Wd in the direction parallel to the drain bus line 14 is, for example, 35 μm. The angle between the trunk portion 28 and the branch portion 30 is, for example, 45°. The width d1 of the slit 34 is, for example, 7 μm, and the width d2 of the space 32 is 3 μm narrower than the width d1 (d1>d2).

In the pixel electrode 16 , the contact region 38 in which the spacer 32 is not formed is formed near the source electrode 24 . In addition, in the pixel electrode 16 , the contact region 39 in which the space 32 is not formed is formed near the storage capacitor electrode 20 . The pixel electrode 16 is electrically connected to the source electrode 24 through a contact hole (not shown) formed in the contact region 38, and is electrically connected to the storage capacitor electrode 20 through a contact hole (not shown) formed in the contact region 39. . In the vicinity of the contact areas 38 , 39 , some branch portions 30 have a shorter length than the other branch portions 30 in order not to form a closed space surrounded by electrodes.

FIG. 4 shows the arrangement of polarizing plates and the like of the liquid crystal display device according to this embodiment. As shown in FIG. 4 , the polarizing plates 83 and 84 are arranged to be crossed polarizers with the liquid crystal layer 48 interposed therebetween. A 1/4 wavelength plate 45 is disposed between the liquid crystal layer 48 and the polarizing plate 83 . In addition, a 1/4 wavelength plate 44 is disposed between the liquid crystal layer 48 and the polarizing plate 84 . Between the liquid crystal layer 48 and the 1/4 wavelength plates 45 and 44, a layer having a negative phase difference such as a TAC film 46 may be arranged to improve viewing angle characteristics. In addition, the upper part of the figure is the observer side, and the lower part of the figure is the light source side.

The angle formed between the optical axis (slow axis) 91 of the 1/4 wavelength plate 45 and the absorption axis 90 of the polarizing plate 83 is approximately 45°. That is, the light emitted from the light source passes through the polarizing plate 83 and the 1/4 wavelength plate 45 in order, and becomes circularly polarized light. Furthermore, the angle formed between the optical axis 94 of the 1/4 wavelength plate 44 and the absorption axis 95 of the polarizing plate 84 is approximately 45°. The optical axes 94, 91 of the two 1/4 wavelength plates 44, 45 are substantially orthogonal to each other. In order to realize the symmetry of the viewing angle and optimize the viewing angle characteristics in the up, down, left, and right directions of the display screen, the polarizing plates 83, 84, and 1/4 wavelength plates 44, 45 are configured as follows.

With reference to the right side of the display screen (direction at 3 o'clock), the absorption axis 90 of the polarizing plate 83 is arranged in a direction rotated 155° counterclockwise. Based on the right side of the display screen, the optical axis 91 of the quarter wave plate 45 and the optical axis 92 of the TAC film 46 disposed on the light source side of the liquid crystal layer 48 are disposed counterclockwise by 20°. Based on the right side of the display screen, the optical axis 93 of the TAC film 46 disposed on the observer side of the liquid crystal layer 48 and the optical axis 94 of the 1/4 wavelength plate 44 are disposed counterclockwise by 110°. With reference to the right side of the display screen, the absorption axis 95 of the polarizing plate 84 is arranged in a direction rotated 65° counterclockwise.

In this embodiment, by arranging a plurality of electrode units 26 in the pixel region, a plurality of regions having different directions of the oblique electric field applied to the liquid crystal layer are formed at relatively narrow intervals. In this way, the inclination angle of the oblique electric field applied to the liquid crystal molecules is increased, and the alignment restriction force on the liquid crystal molecules is enhanced. Therefore, liquid crystal molecules can be tilted in a desired direction without forming protrusions on the CF substrate 4 side.

In addition, in this embodiment, the 1/4 wavelength plates 44, 45 and the polarizing plates 83, 84 are respectively arranged in order on the outer sides of the two substrates 2, 4. The light transmittance at the time of white display in the case of the plates 83 and 84 is about 4%, and the present embodiment can obtain a light transmittance of about 7%. Accordingly, the light transmittance can be about 1.5 times that of the conventional MVA-LCD (light transmittance of about 5%) in which projections are formed on the liquid crystal display substrate shown in FIG. 70 . Therefore, a bright display liquid crystal display device with high luminance can be realized.

(Example 1-2)

Next, the substrate for a liquid crystal display device according to Example 1-2 of this embodiment will be described with reference to FIGS. 5 to 7 . FIG. 5 shows the structure of one pixel of the substrate for a liquid crystal display device according to this embodiment. In the structure of the TFT substrate 2 shown in FIG. 3 , a predetermined gap is formed between the source electrode 24 of the TFT 10 and the pixel electrode 16 . The orientation of the liquid crystal molecules may be deteriorated in the gap, and dark lines may be generated. In the pixel electrode 16 of the TFT substrate 2 according to the present embodiment, in order to suppress the occurrence of dark lines, the oblique angle formed by the branch portion 30 to the trunk portion 28 is not fixed at 45°. As shown in FIG. 5 , in a region A near the source electrode 24 , a branch portion 30 substantially perpendicular to the drain bus line 14 is formed. In the region B, the branch portion 30 substantially perpendicular to the gate bus line 12 is formed. In addition, in a region C near the storage capacitor electrode 20 , a branch portion 30 substantially perpendicular to the drain bus line 14 is formed.

FIG. 6 shows a modified example of the structure of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 6 , a branch portion 30 is formed in a region D near the storage capacitor electrode 20 , and the branch portion 30 is substantially perpendicular to the storage capacitor bus line 18 or substantially parallel to the protruding direction of the connection electrode protruding from the storage capacitor electrode 20 .

FIG. 7 shows another modified example of the structure of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 7 , a main portion 28 is formed in a region E near the storage capacitor electrode 20 . The main portion 28 is inclined with respect to the gate bus line 12 and the drain bus line 14 and is arranged on the tip of the connection electrode 36 . Thus, the extension direction of the trunk portion 28 is substantially parallel to the branch portion 30, thereby reducing the misalignment of the liquid crystal molecules.

(Example 1-3)

Next, a substrate for a liquid crystal display device according to Examples 1-3 of the present embodiment will be described with reference to FIG. 8 . FIG. 8 shows the structure of one pixel of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 8, a slit 34 extending substantially parallel to the drain bus line 14 is formed in the pixel region. Further, in the upper half region in the figure of the pixel region, in the region F, the slit 34 extending substantially parallel to the gate bus line 12 is formed. Whereas, in the region G of the lower half region in the drawing of the pixel region, the slits extending substantially parallel to the gate bus lines 12 are not formed. Thus, more electrode units 26 are formed in the upper half of the pixel region than in the lower half of the pixel region.

As a result, in the lower half region of the pixel region, on the main portion 28 extending substantially parallel to the drain bus line 14, the movement of the liquid crystal molecules becomes poor, and the response time becomes longer. And since the alignment area of the liquid crystal molecules can be more finely divided in the upper half of the pixel area, the response time of the liquid crystal molecules is shortened, and good display characteristics can be obtained.

(Example 1-4)

Next, a substrate for a liquid crystal display device according to Examples 1-4 of this embodiment will be described with reference to FIG. 9 . FIG. 9 shows the structure of one pixel of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 9 , the pixel electrode 16 has: a plurality of electrode units 26 ; a slit 34 formed between the electrode units 26 ; and a connection electrode 36 connecting the plurality of electrode units 26 to each other. The electrode unit 26 is different from the embodiments 1-1 to 1-3 in that the trunk portion 28 , the branch portion 30 and the space 32 are not included.

According to this embodiment, although the response time of the liquid crystal molecules becomes longer, the light transmittance can be increased by about 10% compared with Embodiments 1-2 and 1-3.

(Example 1-5)

Next, the substrate for a liquid crystal display device according to Examples 1-5 of this embodiment will be described with reference to FIGS. 10 and 11 . FIG. 10 shows the structure of one pixel of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 10 , in the region H, the extension direction of the branch portion 30 is set to be only a direction oblique to the gate bus line 12 and the drain bus line 14 . In this way, since there is no region where the alignment direction of the liquid crystal molecules changes rapidly, the liquid crystal molecules can be well aligned.

FIG. 11 shows a modification example of the structure of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 11 , this modification differs from the substrate for a liquid crystal display device shown in FIG. 10 in that a connection electrode 36 is formed at an end portion (region I) of the pixel region. If the connection electrodes 36 are formed between the central portions of the electrode units 26 , the main portions 28 of the plurality of electrode units 26 are connected to the connection electrodes 36 to form linear electrodes substantially parallel to the drain bus lines 14 . As a result, since the length of the trunk portion 28 becomes substantially longer, the position of the singular point is not fixed, and roughness may occur in display. On the other hand, according to this modification, the position of the singular point is fixed, and the roughness of the display can be suppressed.

(Example 1-6)

Next, the substrate for a liquid crystal display device according to Examples 1-6 of this embodiment will be described with reference to FIGS. 12 to 15 . FIG. 12 shows the structure of one pixel of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 12, in this embodiment, on the electrode unit 26 shown in FIG. The pole bus 14 extends substantially parallel or perpendicular to the space 33 , whereby the pattern of the electrode unit 26 formed by the main body 28 , the branches 30 and the space 33 can be simplified. According to the present embodiment, since the space 33 extending substantially perpendicularly to the gate bus line 12 and the drain bus line 14 is formed in the peripheral portion of the pixel region, stable orientation of liquid crystal molecules can be obtained.

FIG. 13 shows a modified example of the structure of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 13 , in this modified example, the formation pattern of the electrode unit 26 is further simplified. FIG. 14 shows a cross-sectional structure of the liquid crystal display device taken along line A-A of FIG. 13 . As shown in FIG. 14 , an insulating film 54 made of, for example, a silicon nitride film (SiN film) is formed on the entire surface of a glass substrate 52 constituting the TFT substrate 2 . Drain bus lines 14 are formed on insulating film 54 . On the entire surface of the drain bus line 14, a protective film 56 made of, for example, a SiN film is formed. On the protective film 56, the connection electrode 36 arrange|positioned at the outer peripheral part of a pixel area is formed. On the other hand, the CF substrate 4 disposed opposite to the TFT substrate 2 has a glass substrate 53 and a common electrode 58 formed on the glass substrate 53 . The cell gap between the TFT substrate 2 and the CF substrate 4 is maintained by columnar spacers 60 formed of resin or the like on the connection electrodes 36 of the TFT substrate 2 .

In this modified example, since the electric field from the connection electrode 36 is shielded by the columnar spacer 60 , disclination surely occurs near the columnar spacer 60 . Therefore, stable orientation of liquid crystal molecules can be obtained, resulting in good display characteristics. In addition, the light transmittance of the liquid crystal display device according to this modified example is about 40% higher than that of the conventional MVA-LCD. In addition, since the patterning of the electrode unit 26 is simplified, the shape of the electrode unit 26 does not vary between pixels during patterning, so that good display characteristics without brightness unevenness can be obtained.

FIG. 15 shows another modified example of the structure of the substrate for a liquid crystal display device according to this embodiment, and shows a cross section corresponding to FIG. 14 . As shown in FIG. 15 , in this modified example, a dielectric 62 made of, for example, a SiN film is formed on the connection electrode 36 . According to this modification, since the electric field from the connection electrode 36 is also shielded by the dielectric 62, the same effect as that of the modification shown in FIG. 14 can be obtained.

The substrate for a liquid crystal display device according to the present embodiment is not limited to the structures described in the foregoing embodiments 1-1 to 1-5. FIG. 16 shows an example of the structure of a substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 16 , in the upper half of the pixel area, long electrode units 26 are formed along the extending direction of the drain bus lines 14 , and in the lower half of the pixel area, long electrode units 26 are formed along the extending direction of the gate bus lines 12 .

FIG. 17 shows another example of the structure of a substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 17, in the pixel region, an electrode unit 26 extending obliquely with respect to the bus lines 12, 14 is formed. Compared with the conventional MVA-LCD, the arrangement interval of the slits 34 is narrowed.

FIG. 18 shows still another example of the structure of the substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 18 , the shape of the electrode unit 26 is the same as that of the liquid crystal display substrate shown in FIG. 6 . The connection electrode 36 of the liquid crystal display substrate shown in FIG. 6 is formed at the center of the pixel region, but the connection electrode 36 of this example is formed at the periphery of the pixel region.

According to the present embodiment, it is possible to realize a substrate for a liquid crystal display device with good display quality and a liquid crystal display device having the substrate without increasing the number of manufacturing steps.

(second embodiment)

Next, a substrate for a liquid crystal display device and a liquid crystal display device having the substrate according to a second embodiment of the present invention will be described. In this embodiment, the following three conditions can be satisfied: (1) no projections made of resin or the like are provided; (3) only by changing the pattern of the pixel electrode 16 on one side of the TFT substrate 2 to limit the orientation of the liquid crystal molecules, and when a voltage is applied, the liquid crystal molecules can be tilted to multiple desired directions.

According to the substrate for a liquid crystal display device of the present embodiment, a plurality of electrode units 26 smaller than the pixel area are provided in the pixel area. The electrode unit 26 has a main part 28 extending in a cross shape, and a branch part 30 branched from the main part 28 and extending toward the outside of the electrode unit 26 .

When the size of the electrode unit 26 is increased, the length of the trunk portion 28 becomes longer. For this reason, it becomes difficult to restrict the alignment direction of the liquid crystal molecules on the trunk portion 28, and poor alignment is likely to occur. On the other hand, if the size of the electrode unit 26 becomes smaller, the restriction of the orientation of the liquid crystal molecules by the branch portion 30 becomes weaker. In addition, since the area occupied by the slits 34 provided by arranging a plurality of electrode units 26 in the pixel area becomes larger, the display brightness decreases. Therefore, it is necessary to form the electrode unit 26 in an appropriate size. Specifically, the maximum length of the branch portion 30 is set to be 25 μm or less.

According to this embodiment, the effects listed below can be obtained.

(1) Since there is no need to form an orientation-regulating structure such as a protrusion on the CF substrate 4 side, the number of manufacturing steps can be reduced.

(2) Only by patterning the pixel electrodes 16 on the TFT substrate 2 side, the inclination direction of the liquid crystal molecules can be restricted. Accordingly, since these can be formed in the same process as that of the conventional pixel electrode 16 , there is no need to increase the number of manufacturing steps.

(3) In order to form an alignment film on both substrates 2 and 4, it is only necessary to apply a vertical alignment film and form a film, and there is no need for a process of imparting an alignment restriction force by rubbing with a cloth or light alignment.

As described above, since the manufacturing yield does not decrease due to the increase of the manufacturing process, the manufacturing yield can be improved as a result.

Furthermore, according to the present embodiment, by configuring the pixel electrode 16 with a plurality of electrode units 26 having a small size, the following effects can be obtained.

(4) In one electrode unit 26, because the inclination direction of the liquid crystal molecules is restricted by the branch portion 30 extending in four directions, compared with the existing structure, the alignment restricting force of the liquid crystal molecules is enhanced, and the disorder of the alignment is difficult. occur. In addition, by arranging a plurality of electrode units 26, the influence of misorientation can be reduced.

(5) Since the length of the trunk portion 28 forming the boundary line of the orientation region becomes shorter, the orientation restricting force (with direction) of the trunk portion 28 becomes larger than that when the length is longer. Therefore, it is possible to suppress the occurrence of a singular point of the trunk portion 28 .

(6) By reducing the size of the electrode unit 26 , the orientation restricting force caused by the electric field of the pixel electrode 16 can be increased, and therefore, the response time can be further shortened.

Furthermore, a pair of 1/4 wavelength plates 44 and 45 having optical axes perpendicular to each other are disposed between the liquid crystal display panel produced by applying this embodiment and the polarizing plates 83 and 84 . Therefore, compared with the case where only the polarizing plates 83 and 84 are arranged, since light can pass through the boundary line of the alignment area without generating dark lines, the overall brightness can be improved.

In addition, a connection electrode 36 electrically connecting adjacent electrode units 26 is formed at an end portion of the pixel region adjacent to the drain bus line 14 . Therefore, since the trunk portions 28 of the adjacent electrode units 26 are not connected in a straight line, the misalignment that occurs once is not connected to the adjacent electrode units 26 . Therefore, good display characteristics can be obtained. Hereinafter, the substrate for a liquid crystal display device according to the present embodiment and the liquid crystal display device having the substrate will be specifically described using Examples 2-1 to 2-3.

(Example 2-1)

First, the substrate for a liquid crystal display device according to Example 2-1 of this embodiment will be described with reference to FIGS. 19 to 26D. FIG. 19 shows the structure of a substrate for a liquid crystal display device according to this embodiment. As shown in FIG. 19 , a plurality of gate bus lines 12 extending in the horizontal direction in the figure are formed at intervals of, for example, 300 μm. A plurality of drain bus lines 14 extending vertically in the figure are formed at intervals of, for example, 100 μm. The gate bus line 12 and the drain bus line 14 have a width of, for example, 7 μm. The interval between the ends of the gate bus line 12 and the drain bus line 14 and the end of the pixel electrode 16 is, for example, 8 μm. That is, the pixel electrode 16 has a substantially rectangular outer periphery with a short side of approximately 77 μm.

The pixel electrode 16 has a plurality of electrode units 26 having a rectangular outer periphery, and the length of one side thereof is not less than 20 μm and not more than 80 μm (in FIG. 19 , a total of 12 electrode units 26 having a square outer periphery of 35 μm×35 μm are formed). . Two electrode units 26 are arranged along the extending direction of the gate bus 12 , and six are arranged along the extending direction of the drain bus 14 (every three sandwiches one storage capacitor bus 18 ). Each electrode unit 26 has a square outer periphery constituted by four sides substantially parallel to or perpendicular to the gate bus line 12 and the drain bus line 14 . A cross-shaped trunk portion 28 is formed in the electrode unit 26, and the trunk portion 28 extends along a straight line starting from an intersection connecting the squares on the outer periphery in an oblique shape and ending at four vertices on the outer periphery of the square. The trunk portion 28 is a rectangle with substantially the same width (both sides in the longitudinal direction are substantially parallel), and has a triangular shape with narrowed ends (near the end point) in accordance with the shape of the outer periphery of the electrode unit 26 . The trunk portion 28 has a width of not less than 3 μm and not more than 10 μm. The electrode unit 26 has four alignment regions divided by the trunk portion 28 in which the liquid crystal molecules are aligned in different directions.

In addition, the electrode unit 26 has a plurality of branch portions 30 branched from the trunk portion 28 and extending substantially parallel to or perpendicular to the gate bus line 12 and the drain bus line 14 (inclined with respect to the trunk portion 28 ). The branch portion 30 has a width of 2 μm to 10 μm (for example, 3 μm), and a length of 25 μm or less. Spaces 32 are formed between adjacent branch portions 30 . The space 32 has a width of not less than 2 μm and not more than 10 μm (for example, 3 μm). The angle formed between the trunk portion 28 and the branch portion 30 is, for example, 45°. In addition, the angle formed between each side of the outer periphery of the electrode unit 26 and the branch portion 30 is, for example, 90°.

Although the shapes of the 12 electrode units 26 are basically the same, there are also some electrode units 26 with different shapes. The pixel electrode 16 must be electrically connected to the source 24 of the TFT 10 . For this reason, the pixel electrode 16 and the source electrode 24 are connected through a contact hole (not shown in the figure) formed on the protective film 56 (not shown in FIG. 19 ). Considering the margin for pattern formation when forming the contact hole, the region connecting the pixel electrode 16 and the source electrode 24 must have a pixel electrode formation layer of a certain size and relatively large size. Therefore, in the upper left electrode unit 26 of the pixel area in FIG. 19 , a contact area (plate-like contact electrode) 38 in which a pixel electrode forming material is formed over the entire surface in a square area of about 15 μm×15 μm is arranged.

In addition, the drain 22 of the TFT 10 in the pixel region adjacent to the lower part of the figure is exposed and formed in the lower part of the pixel region. If the pixel electrode 16 and the drain electrode 22 are formed to overlap each other when viewed from a direction perpendicular to the substrate surface, alignment disorder of the liquid crystal molecules may occur in this region, and crosstalk may occur. For this reason, it is necessary not to overlap the pixel electrode 16 and the drain electrode 22 . Therefore, it is necessary to form the shape of the electrode unit 26 (at the lower left in FIG. 19 ) of this region to be shorter in the direction (longitudinal direction) of the drain bus line 14 . Specifically, the outer peripheral shape of the other electrode units 26 is a square of 35 μm×35 μm, while the longitudinal length of the outer peripheral shape of the electrode unit 26 in this region is reduced by 10 μm to a rectangle of 25 μm×35 μm. The starting point of the trunk portion 28 is arranged at approximately the central position of the electrode unit 26 , and the ending points are arranged on two sides of the outer peripheral rectangle substantially parallel to the gate bus line 12 , with two ending points on each side.

When a plurality of electrode units 26 are arranged, slits 34 for electrically separating the electrode units 26 are formed between adjacent electrode units 26 . The slit 34 has a width of not less than 4 μm and not more than 10 μm (for example, 7 μm). However, the electrode units 26 in the same pixel area must be electrically connected. For this purpose, connection electrodes 36 for connecting the electrode units 26 are provided between the electrode units 26 . The connection electrode 36 is arranged in the vicinity of the drain bus line 14 (peripheral portion of the pixel region). Specifically, the connection electrodes 36 are formed so that among the four main parts 28 of the electrode unit 26 , the main parts 28 on the side adjacent to the drain bus line 14 are connected to each other. The extension direction of the connection electrode 36 is inclined at about 45° with respect to the extension direction of the trunk portion 28 . The connection electrodes 36 formed on the storage capacitor bus 18 (storage capacitor electrodes 20 ) are connected between the adjacent electrode units 26 in the direction of the gate bus line 12 . Viewed from a direction perpendicular to the substrate surface, the storage capacitor bus line 18 is formed to overlap the slit 34 .

Not shown in FIG. 19 , a BM 40 that shields the end of the pixel region from light is formed on the side of the CF substrate 4 disposed opposite to the TFT substrate 2 . BM40 is formed in a lattice shape with a width of, for example, 23 μm. The grid interval in the extending direction of the gate bus line 12 is 100 μm, and the grid interval in the extending direction of the drain bus line 14 is 300 μm. On the opening of the BM40, any of red (R), green (G), and blue (B) is formed. A CF resin layer. A common electrode made of, for example, ITO is formed on the entire surface of the CF resin layer.

Alignment films are formed on the facing surfaces of the two substrates 2,4. This alignment film has vertical alignment and orients liquid crystal molecules in a direction perpendicular to the substrate surface (orientation film surface) in a normal state. A liquid crystal display device is produced by injecting liquid crystal having negative dielectric anisotropy into a liquid crystal cell obtained by pasting the two substrates 2 and 4 and sealing it.

FIG. 20 shows the alignment state and display state of liquid crystal molecules of the liquid crystal display device according to this embodiment. Arrows in the figure indicate the inclination directions of the liquid crystal molecules when a voltage is applied to the liquid crystal layer. FIG. 20 shows three pixels defined by BM40. As shown in FIG. 20 , four alignment regions are formed in the liquid crystal display device according to the present embodiment, which have the diagonals of the squares at the outer peripheries of the respective electrode units 26 as boundaries. In each alignment area, the liquid crystal molecules are tilted toward the center of the electrode unit 26 . In addition, in one pixel, the areas of the orientation regions are substantially equal.

One electrode unit 26 is formed to have a size of about 35 μm×35 μm smaller than the pixel area. Therefore, the effect of the electric field on the main portion 28 of the pixel electrode 16 and the tip portion of the branch portion 30 can be increased, and the alignment control force of the liquid crystal molecules can be enhanced. Furthermore, in the liquid crystal display device according to the present embodiment, the connection electrodes 36 between the connection electrode units 26 are arranged in the vicinity of the drain bus lines 14 . Therefore, poor orientation caused by connecting the oblique directions of the liquid crystal molecules on two adjacent electrode units 26 through the slit 34 is less likely to occur, thereby preventing deterioration of display quality.

Furthermore, the boundary lines of the orientation areas are seen as dark lines 42 . The area where the slit 34 is formed is seen as a dark line 43 . However, since these dark lines 42 and 43 are generated at the same position in each pixel, the display quality will not be degraded.

Fig. 21 shows the alignment state and display state of the liquid crystal molecules of the liquid crystal display device according to the present embodiment. On the outsides of the two substrates 2 and 4 of the liquid crystal display device, 1/4 wavelength plates 44, 45 are respectively arranged in the following order. and polarizing plates 83,84. As shown in FIG. 21, in a liquid crystal display device in which 1/4 wavelength plates 44, 45 and polarizing plates 83, 84 are disposed on the outer sides of the two substrates 2, 4 in the following order, since the light transmittance does not depend on the liquid crystal The oblique direction of the molecules, therefore, the dark line 42 is not visible except for the singular point formed at the center portion of the electrode unit 26 which is seen as the dark spot 50 . Therefore, higher brightness display can be realized.

22A to 25B show formation patterns of the electrode unit 26 . In FIGS. 22A to 25B , the arrows arranged in the respective alignment regions indicate the tilt directions of the liquid crystal molecules. FIG. 22A shows a formation pattern of the same electrode unit 26 as the electrode unit 26 shown in FIG. 19 . As shown in FIG. 22A , end points G1 to G4 of the trunk portion 28 are arranged at respective vertices of the outer peripheral rectangle. In addition, the starting point S of the trunk portion 28 is arranged at the intersection of diagonal lines connecting two non-adjacent terminal points (G1 and G3, G2 and G4) in an oblique shape among the terminal points G1 to G4. When the outer perimeter is a square, the two diagonals are orthogonal. The straight lines connecting the starting point S to the four end points G1-G4 become the boundary lines defining the alignment area, and become dark lines on the completed liquid crystal display device. The branch portion 30 branches obliquely from the trunk portion 28 . The extending direction of the branch portion 30 has an angle of 90° with respect to one side of the outer circumference of the electrode unit 26 .

The coordinates of the starting point S are the coordinates between two adjacent end points (G1 and G2, G2 and G3, G3 and G4, G4 and G1). In addition, the angle formed between two straight lines connecting two adjacent end points from the starting point S is smaller than 180°. The angle is preferably around 90°. By setting the shape of the trunk portion 28 in this way, the shape of each orientation area can be divided into four parts with equal areas as much as possible without distortion. As long as the above conditions are satisfied, the shape of the electrode unit 26 may be changed.

FIG. 22B shows a first modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 22B , the starting point S is arranged at an arbitrary position within the electrode unit 26 . The end points G1 to G4 are arranged on each side of the rectangle on the outer periphery of the electrode unit 26 , one on each side. Furthermore, in this embodiment, it is assumed that a "side" includes vertices at both ends of the side.

FIG. 22C shows a second modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 22C , the starting point S is arranged at an arbitrary position within the electrode unit 26 . The end points G1 and G4 are arranged on one side of the outer peripheral rectangle of the electrode unit 26 , and the end point G3 is arranged on the side opposite to the side. In addition, the end point G2 is arranged on another side.

FIG. 22D shows a third modification of the patterning of the electrode unit 26 . For example, as shown in FIG. 22D , the starting point S is arranged at any position in the electrode unit 26 . The end points G1 and G4 are arranged on one side of the outer peripheral rectangle of the electrode unit 26 , and the end points G2 and G3 are respectively arranged on two sides other than the side opposite to the side.

FIG. 22E shows a fourth modification example of the formation pattern of the electrode unit 26 . As shown in FIG. 22E , the starting point S is arranged at any position within the electrode unit 26 . The end points G1 and G4 are arranged on one side of the outer peripheral rectangle of the electrode unit 26 , and the end points G2 and G3 are arranged on the side opposite to the side.

FIG. 22F shows a fifth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 22F , the starting point S is arranged at any position within the electrode unit 26 . The end points G1 to G4 are respectively arranged at the vertices of the rectangle on the outer periphery of the electrode unit 26 .

FIG. 22G shows a sixth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 22G, the end points G1-G4 are respectively arranged on the sides of the rectangle of the outer periphery of the electrode unit 26, and the starting point S is arranged between two non-adjacent end points among the end points G1-G4 (G1 and G3, G2 and G4) At the intersection of straight lines connected obliquely.

FIG. 22H shows a seventh modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 22H , the end points G1 to G4 are respectively arranged at the positions of the respective sides of the rectangle that equally divides the outer periphery of the electrode unit 26 . The starting point S is arranged at the intersection of straight lines connecting two non-adjacent end points (G1 and G3, G2 and G4) obliquely among the end points G1 to G4.

FIG. 23A shows an eighth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 23A , end points G1 to G4 are respectively arranged at vertices of a rectangle on the outer periphery of electrode unit 26 . The starting point S is arranged at the intersection of straight lines connecting two non-adjacent end points (G1 and G3, G2 and G4) obliquely among the end points G1 to G4. The extending direction of the branch portion 30 has an angle θ1 of not less than 45° and not more than 90° with respect to one side of the outer periphery of the electrode unit 26 . In each orientation area, the extending directions of the branch portions 30 are substantially parallel to each other. In this modified example, the azimuth direction of the liquid crystal molecules is different from the above-described embodiments and modified examples. However, if the 1/4 wavelength plates 44, 45 and the polarizing plates 83, 84 are respectively arranged in the following order outside the two substrates 2, 4 of the liquid crystal display device, because the light transmittance does not depend on the azimuth direction of the liquid crystal molecules , so this modification can be applied.

FIG. 23B shows a ninth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 23B , the shape of the trunk portion 28 is the same as that of the eighth modification. The extending direction of the branch portion 30 has an angle θ2 of approximately 45° with respect to one side of the outer circumference of the electrode unit 26 . In this case, the branch portion 30 is branched from only one side of the trunk portion 28 . In each orientation area, the extending directions of the branch portions 30 are substantially parallel to each other.

FIG. 23C shows a tenth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 23C , the shape of the trunk portion 28 is the same as that of the eighth and ninth modifications. The extending directions of the branch portions 30 are not parallel to each other in the orientation area. For example, assuming that the angles between the extension directions of the four branch portions 30 and one side of the outer circumference of the electrode unit 26 are sequentially (based on the starting point, clockwise) θ3 (θ3≤90°), θ4, θ5, θ6, Then 45°≤θ3≤θ4≤θ5≤θ6≤135°. That is, the plurality of branch portions 30 expand and extend approximately fan-shaped from each other. Here, if the difference between the angles θ3 and θ6 is too large, the intervals of the branch portions 30 will spread too much in the outer peripheral portion, and the intervals of the branch portions will become narrow near the trunk portion 28. Therefore, it is possible to set The range of the predetermined angles θ3 to θ6 is itself limited.

FIG. 24A shows an eleventh modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 24A, the trunk portion 28 gradually narrows in width from the base (starting point) to the tip (end point).

FIG. 24B shows a twelfth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 24B , the trunk portion 28 is formed into a rectangle having substantially the same width. The top end of the trunk portion 28 may be contained within the outer peripheral rectangle, or may be exposed from the outer peripheral rectangle.

FIG. 24C shows a thirteenth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 24C , the trunk portion 28 is formed in a shape bent in the middle of a "ㄑ" character. As shown in FIGS. 24A to 24C , even if the shape is changed, since the trunk portion 28 functions as a boundary of the alignment region, the alignment state of the liquid crystal molecules does not change much.

FIG. 25A shows a fourteenth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 25A , the branch portion 30 gradually narrows in width from the base connected to the trunk portion 28 to the tip. Although not shown in the figure, the branch portion 30 may be formed so that only the width of the tip portion is narrowed, or may be formed so as to be bent in the middle.

FIG. 25B shows a fifteenth modified example of the formation pattern of the electrode unit 26 . As shown in FIG. 25B , the trunk portions 28 facing each other around the starting point are formed in a state of being offset from each other. Specifically, the offset width W2 is made not smaller than the width W1 of the trunk portion 28 (W2≧W1). In this way, the rotation direction of the liquid crystal molecules near the singular point (the rotation direction of the boundary crystal domains) can be fixed. In this way, even if the shape is changed, because the trunk portion 28 can also play the role of an orientation division boundary, the liquid crystal The orientation state of the molecules will not change much. In addition, the offset width W2 may be narrower than the width W1 of the trunk portion 28 (W2<W1).

26A to 26D show the formation patterns of the connection electrodes 36 . In FIGS. 26A to 26D , the dotted arrows arranged on the slits 34 indicate the inclination directions of the liquid crystal molecules on the slits 34 . FIG. 26A shows the same formation pattern of the connection electrodes 36 as the connection electrodes 36 shown in FIG. 19 . As shown in FIG. 26A , the connecting electrodes 36 are formed between the distal ends of the trunk parts 28 facing each other through the slits 34 .

FIG. 26B shows a first modified example of the formation pattern of the connection electrodes 36 . As shown in FIG. 26B , the connection electrodes 36 are formed between the tip ends of the branch portions 30 facing each other through the slits 34 extending parallel to each other. The extending direction of the connection electrode 36 is substantially parallel to the extending direction of the branch portion 30 .

FIG. 26C shows a second modified example of the patterning of the connection electrodes 36 . As shown in FIG. 26C , the connection electrodes 36 are formed between the tip portions of the branch portions 30 other than the branch portions 30 facing each other through the slits 34 . The extending direction of the connection electrode 36 is inclined relative to the extending direction of the branch portion 30 .

FIG. 26D shows a third modified example of the patterning of the connection electrodes 36 . Not shown in the figure, the drain bus line 14 extending in the vertical direction in the figure is adjacent to the right side of the electrode unit 26 in the figure. As shown in FIG. 26D, the connection electrode 36 is arranged between the branch portions 30 extending along one side of the drain bus line 14, and has: an extension portion 36a extending in a direction substantially parallel to the extending direction of the branch portion 30; 36b, which is connected between the extensions 36a and extends in a direction substantially parallel to the drain bus line 14.

In addition, instead of the connection electrode 36 , a second connection electrode that connects the source electrode 24 and the electrode unit 26 may be formed of a material different from that of the trunk portion 28 and the branch portion 30 . The second connection electrode is formed, for example, between the source electrode 24 and the vicinity of the starting point of the electrode unit 26 .

According to the first to fifteenth modification examples, the same effect as that of the above-mentioned embodiment can be obtained. 22A to 25B show the electrode unit 26 having a substantially square outer periphery, but the electrode unit 26 may have another rectangular outer periphery. In addition, the electrode unit 26 may also have an approximately rectangular outer periphery. As an example, a shape in which rounded corners having a predetermined radius are formed near each apex of a rectangle can be mentioned.

(Example 2-2)

Next, a substrate for a liquid crystal display device according to Example 2-2 of this embodiment will be described with reference to FIGS. 27 to 29 . FIG. 27 shows the structure of a substrate for a liquid crystal display device according to this embodiment. In the present embodiment, the electrode unit 26 has a rectangular outer circumference of 77 μm×35 μm. The starting point of the main body portion 28 is arranged at the center of the electrode unit 26 , and the end point of the main body portion 28 is arranged at positions on each side of the outer peripheral rectangle of the electrode unit 26 . That is to say, the electrode unit 26 is divided into four orientation areas of the upper left, the upper right, the lower left, and the lower right in the figure. The branch portion 30 that restricts the alignment direction of the liquid crystal molecules is formed by branching from the trunk portion 28 in an oblique direction, forming an angle of 45° with respect to the gate bus line 12 and the drain bus line 14 .

One electrode unit 26 is arranged along the extending direction of the gate bus line 12 , and six are arranged along the extending direction of the drain bus line 14 (every three sandwiches one storage capacitor bus line 18 ). A connection electrode 36 for connecting adjacent electrode units 26 is formed between the opposing trunk parts 28 through the slit 34 .

FIG. 28 shows the alignment state and display state of liquid crystal molecules of the liquid crystal display device according to this embodiment. Arrows in the figure indicate the directions in which the liquid crystal molecules are inclined when a voltage is applied to the liquid crystal layer. In FIG. 28, three pixels defined by BM40 are shown. As shown in FIG. 28, in the liquid crystal display device according to the present embodiment, four alignment regions are formed with the trunk portion 28 of each electrode unit 26 as a boundary line. In each alignment area, the liquid crystal molecules are inclined in a direction toward the center portion of the electrode unit 26 . In addition, within one pixel, the area of each orientation area is substantially the same.

One electrode unit 26 is formed smaller than the pixel area, and its size is about 77 μm×35 μm. Therefore, the main part 28 of the pixel electrode 16 and the tip part of the branch part 30 can have a large electric field effect, and the alignment limiting force of the liquid crystal molecules can be enhanced. Furthermore, the boundary line of the orientation area is seen as a dark line 42 , and the area where the slit 34 is formed is seen as a dark line 43 . However, since these dark lines 42 and 43 are generated at the same position in each pixel, the display quality will not be degraded.

29 shows the orientation state of the liquid crystal molecules of the liquid crystal display device in which the 1/4 wavelength plates 44, 45 and the polarizing plates 83, 84 are arranged in sequence on the outside of the two substrates 2, 4 of the liquid crystal display device according to this embodiment. and display status. As shown in FIG. 29 , in a liquid crystal display device in which 1/4 wavelength plates 44 , 45 and polarizing plates 83 , 84 are respectively arranged on the outer sides of the two substrates 2 , 4 in the above order, since the light transmittance does not depend on the liquid crystal molecules Therefore, the dark line 42 is not seen except for the singular point formed at the central portion of the electrode unit 26 which is seen as the dark spot 50 . Therefore, higher brightness display can be realized.

(Example 2-3)

Next, a substrate for a liquid crystal display device according to Example 2-3 of this embodiment will be described with reference to FIGS. 30 to 32 . FIG. 30 shows the structure of a substrate for a liquid crystal display device according to this embodiment. In this embodiment, the plurality of gate bus lines 12 extending in the horizontal direction in the drawing are formed at intervals of, for example, 225 μm, and the plurality of drain bus lines 14 extending in the vertical direction in the drawing are formed at intervals of, for example, 75 μm. Compared with Examples 2-1 and 2-2, the pixel area becomes smaller. The gate bus line 12 and the drain bus line 14 have a width of, for example, 6 μm. The distance between the ends of the gate bus lines 12 and the drain bus lines 14 and the ends of the pixel electrodes 16 is, for example, 7 μm. That is, the short side of the pixel electrode 16 having a substantially rectangular outer circumference is about 55 μm.

The electrode unit 26 has a square outer circumference of 55 μm×55 μm. The starting point of the trunk portion 28 is arranged at the center of the electrode unit 26 , and the end points of the trunk portion 28 are respectively arranged at vertices of the outer peripheral rectangle of the electrode unit 26 . The branch portion 30 that limits the alignment direction of the liquid crystal molecules is formed as follows: branches from the trunk portion 28 in an oblique direction, and are substantially parallel or perpendicular to the gate bus line 12 and the drain bus line 14 . The branch portion 30 has a width of, for example, 3 μm. Furthermore, the space 32 has a width of, for example, 3 μm. The angle formed between the trunk portion 28 and the branch portion 30 is, for example, an angle of 45°. In addition, the included angle between the branch portion 30 and the outer peripheral sides of the electrode unit 26 is, for example, 90°.

One electrode unit 26 is arranged in the extending direction of the gate bus line 12 , and three are arranged in the extending direction of the drain bus line 14 . Viewed from a direction perpendicular to the substrate surface, the storage capacitor bus line 18 is arranged to overlap the slit 34 . Therefore, the storage capacitor bus line 18 is not arranged at the center of the pixel area, but is arranged at a position deviated upward or downward. Specifically, storage capacitor bus lines 18 (storage capacitor electrodes 20 ) having a width of, for example, 20 μm are formed around a position about 150 μm away from the upper gate bus line 12 and about 70 μm away from the lower gate bus line 12 .

Two electrode units 26 are arranged in the upper opening area and one in the lower opening area, with the storage capacitor bus line 18 as the boundary. However, as in Example 2-1, the shapes of some electrode units 26 are changed. In the electrode unit 26 above the pixel region, a contact region 38 in which a pixel electrode forming material is formed over the entire surface in a square region of approximately 15 μm×15 μm is arranged. In addition, a cutout is provided on the electrode unit 26 below the pixel region so that the end of the drain electrode 22 and the end of the pixel electrode 16 are separated by, for example, 7 μm.

The connection electrode 36 connecting the adjacent electrode units 26 is arranged in the vicinity of the drain bus line 14 (peripheral portion of the pixel region). The connecting electrodes 36 are formed in a direction substantially parallel to the drain bus lines 14 and are connected between the opposing stem parts 28 through the slits 34 . The slit 34 has a width of, for example, 7 μm.

Not shown in FIG. 30 , on the side of the CF substrate 4 disposed opposite to the TFT substrate 2 , a BM 40 for shielding light from the end of the pixel region is formed. BM40 is formed in a lattice shape with a width of, for example, 20 μm. The grid interval in the extending direction of the gate bus lines 12 was 75 μm, and the grid interval in the extending direction of the drain bus lines 14 was 225 μm. Any one of R, G, and B CF resin layers is formed in the opening of BM40. A common electrode made of, for example, ITO is formed on the entire surface of the CF resin layer.

FIG. 31 shows the alignment state and display state of liquid crystal molecules of the liquid crystal display device according to this embodiment. Arrows in the figure indicate the directions in which the liquid crystal molecules are inclined when a voltage is applied to the liquid crystal layer. In FIG. 31, three pixels defined by BM40 are shown. As shown in FIG. 31 , on the liquid crystal display device according to the present embodiment, four alignment regions having the trunk portion 28 of each electrode unit 26 as a boundary line are formed. In each alignment area, the liquid crystal molecules are inclined in a direction toward the center portion of the electrode unit 26 . In addition, within one pixel, the area of each orientation area is substantially the same.

One electrode unit 26 is formed smaller than the pixel area, and its size is about 55 μm×55 μm. Therefore, the main part 28 of the pixel electrode 16 and the tip part of the branch part 30 can have a large electric field effect, and the alignment limiting force of the liquid crystal molecules can be enhanced. Furthermore, the boundary line of the orientation area is seen as a dark line 42 , and the area where the slit 34 is formed is seen as a dark line 43 . However, since these dark lines 42 and 43 are generated at the same position in each pixel, the display quality will not be degraded.

FIG. 32 shows the alignment state of liquid crystal molecules in a liquid crystal display device in which quarter wavelength plates 44, 45 and polarizing plates 83, 84 are arranged in sequence on the outer sides of the two substrates 2, 4 of the liquid crystal display device according to this embodiment. and display status. As shown in FIG. 32, in the liquid crystal display device in which the 1/4 wavelength plates 44, 45 and the polarizing plates 83, 84 are respectively arranged on the outer sides of the two substrates 2, 4 in the above order, since the light transmittance does not depend on the liquid crystal Because of the oblique direction of the molecules, the dark line 42 is not seen except for the singular point 50 formed at the center of the electrode unit 26 which is seen as a dark spot. Therefore, higher brightness display can be realized.

As described above, in the present embodiment, only by changing the formation pattern of the pixel electrodes 16, it is possible to apply an alignment restricting force to the liquid crystal molecules. In addition, since poor alignment of liquid crystal molecules is reduced, a liquid crystal display device with good display quality can be realized with high manufacturing yield and low manufacturing cost. In addition, if the 1/4 wavelength plates 44, 45 and the polarizing plates 83, 84 are respectively arranged in sequence on the outside of the two substrates 2, 4 of the liquid crystal display device according to this embodiment, a higher brightness liquid crystal display can be easily realized. device.

In addition, the number of electrode units 26 in one pixel is not limited to the number described in the above embodiments. For example, if one electrode unit 26 is arranged along the gate bus line 12 , two to six electrode units 26 are arranged along the drain bus line 14 . If two electrode units 26 are arranged along the gate bus line 12 , four or more and 12 or less electrode units 26 are arranged along the drain bus line 14 . If three electrode units 26 are arranged along the gate bus line 12 , 6 or more and 18 or less electrode units 26 are arranged along the drain bus line 14 .

(third embodiment)

Next, a substrate for a liquid crystal display device and a liquid crystal display device having the substrate according to a third embodiment of the present invention will be described. This embodiment will describe a liquid crystal display device that relates to a method of improving the display characteristics of a liquid crystal display device by performing orientation control using a fine electrode pattern, even if the liquid crystal panel may be caused or caused by pressing the liquid crystal panel with a finger or the like in actual use. The alignment state of the liquid crystal display device is quite stable even with more or less shocks, and there is no problem of display defects such as color spots on the display.

Compared with the TN-type liquid crystal display devices widely used so far, the MVA-LCD currently mass-produced has advantages such as high contrast ratio and wide viewing angle. But on the other hand, its light transmittance is sometimes worse than that of TN-type LCD. The reason lies in the directional control method of the MVA type. The pixels of MVA-LCD have linear electrode removal patterns or structures, and due to the shape effect of the linear structures and the distortion effect of the electric field applied to the liquid crystal layer when a voltage is applied, the orientation of the liquid crystal is controlled to a desired direction. At this time, since it is difficult to apply a predetermined voltage to the liquid crystal molecules in the vicinity of the linear structure or the electrode-removed portion, the liquid crystal molecules in this area cannot be sufficiently tilted. Therefore, light transmittance within the pixel is lowered.

In addition, in the orientation control of the MVA method, the liquid crystal molecules at a position close to the linear structure and the electrode-removed part are oriented perpendicular to the long-side direction of the linear structure when a voltage is applied, forming a large crystal structure. Domain. On the other hand, the liquid crystal molecules on the linear structure and the electrode-removed portion are aligned parallel to the linear structure to form elongated crystal domains. Since the orientation of the liquid crystal changes continuously, in the middle of the two crystal domains, there is a direction at 45° relative to the linear structure, that is, a region where the orientation direction is the same as the direction of the polarization axis of the polarizing plate. This also reduces light transmittance.

In order to improve this problem of low light transmittance, a new MVA method combining the following two methods is considered.

The first method utilizes a circular polarizing plate. Therefore, since the light transmittance is determined only by retardation in principle and has nothing to do with the alignment direction of the liquid crystal molecules, the light transmittance can be improved. That is to say, in the existing structure, the light in the area where the orientation direction is consistent with the direction of the polarization axis will not pass through, but according to the circular polarization method, the light transmittance of this area can be increased to 45° relative to the polarization axis. The transmittance of the region in the ° direction.

In the second mode, the orientation control is performed using the electrode unit 26 having a fine electrode pattern. Conventionally, in a pixel of about 100 μm×300 μm, several linear electrode removal portions or linear structures with a width of about 100 μm are arranged obliquely, which causes a large loss of light transmittance. On the other hand, it has been found that, as described in the above-mentioned first and second embodiments, for example, lines and spaces having a width of about 3 μm are repeatedly used to form a fine electrode pattern, and multiple electrodes having such a fine electrode pattern are reused. With only one electrode unit 26, the liquid crystal molecules can be controlled in a certain direction. In this case, the liquid crystal molecules are oriented parallel to the long side direction of the fine pattern, and the light transmittance hardly decreases. Therefore, light transmittance can be improved by using such a group of electrode units 26 .

However, in the liquid crystal display device to which these methods are applied, in actual use, when the liquid crystal panel is pressed with a finger or the like, some impact may be caused, and the occurrence of display color unevenness may be observed. In order to find out the cause, the alignment state of the liquid crystal panel was investigated. The results are shown in Figures 33A to 33D. In addition, in order to observe the alignment state in detail, this result is a result of observing with a normal linear polarizing plate after removing the circular polarizing plate.

In particular, FIGS. 33A and 33B show a liquid crystal panel that performs normal display without any impact. FIG. 33A shows a micrograph of the display state of a predetermined display region, and FIG. 33B shows the shape of the electrode unit 26 and the occurrence of singular points. In this example, the electrode pattern is basically the same as that shown in FIG. 26A according to the second embodiment, but the pixel electrode 16 having connection electrodes 36 formed on both sides is used. The very small rod-like objects present in the electrode patterns shown in FIG. 33B and FIG. 33D indicate the orientation direction of 1 cm of liquid crystal molecules. In addition, in the following description, the same code|symbol is attached|subjected to the same component as the component used in 1st and 2nd embodiment, and the description is abbreviate|omitted. As shown in FIGS. 33A and 33B , when a voltage is applied to the electrode unit 26 , crystal domains are formed according to the orientation control of the fine electrode pattern group of the electrode unit 26 . At the boundary portion of the crystal domains, singular points of orientation vectors (perpendicularly oriented point-like regions) are formed. As shown in Fig. 33A and Fig. 33B, it can be seen that at the singular point of intensity s=+1 (indicated by area a in the figure), the singular point of intensity s=-1 (indicated by area b in the figure) and the singular point by Three forms of regions (indicated by region c in the figure) arranged in the order of intensity s=-1, +1, -1. In FIG. 33B and FIG. 33D , singular points with intensity s=+1 are indicated by ● marks, and singular points with intensity s=-1 are indicated by ○ marks.

Next, FIG. 33C and FIG. 33D show the surface of the liquid crystal panel that is impacted by pressing the display surface of the liquid crystal panel with a finger. FIG. 33C is a micrograph showing the display state of a predetermined display region, and FIG. 33D shows the shape of the electrode unit 26 and the occurrence of singular points. As shown in FIG. 33C and FIG. 33D , when the display surface of the liquid crystal panel is pressed with a finger, the alignment state of the impacted portion and the peripheral portion greatly changes, and the alignment direction is stabilized in this state. Comparing with FIG. 33A and FIG. 33B , it can be seen that the display domains are connected across the positions where the original domain boundaries existed, and the singularity point has disappeared.

According to the display method using a circularly polarizing plate, when the liquid crystal panel is viewed from the normal direction, in principle, a change in the alignment state (orientation direction) is not seen as a difference in brightness. However, when the liquid crystal panel is viewed from a slightly oblique direction, the angle between the polarization axis of the linear polarizing plate constituting the circular polarizing plate and the optical axis of the retardation plate (λ/4 plate) is different from that seen from the normal direction. Compared with the angle of time, there is a visual change, and the phase difference of the phase difference plate itself also has a visual change. As a result, the characteristics of the circularly polarizing plate deviate from the ideal circularly polarizing plate. Therefore, when a large orientation change occurs, even if a circularly polarizing plate is used, unevenness in brightness can be seen from an actual liquid crystal panel.

In this way, it is considered that the cause of the display color unevenness is that the orientation of the liquid crystal in the pixel is greatly changed by pressing with a finger. In this embodiment mode, a description will be given of a liquid crystal display device whose alignment state is stable even when a more or less shock may be caused by pressing the liquid crystal panel with a finger or the like in actual use and does not Display defects such as color spots may be caused.

The first principle of stable orientation according to this embodiment will be described. As shown in FIGS. 33A to 33D , it turns out that singular points are formed at the boundaries of crystal domains in many cases. In addition, the formation position of the singular point cannot be effectively controlled with the structures shown in FIGS. 33A to 33D. Therefore, it can be considered that shocks such as finger pressure make the singularity point move or disappear easily. Furthermore, the movement and disappearance of the singular point causes a large orientation change in which domains are connected across domain boundaries.

That is, since the singular point has disappeared, it can be considered that the liquid crystal domains are connected together. On the contrary, if the singular point is stably formed, it can be considered that the liquid crystal domains are not connected. In particular, the three singular point formation states seen in FIGS. 33A to 33D are the states that were originally stably realized with the electrode structures shown in FIGS. 33A to 33D . Therefore, it is considered that in order to realize stable orientation, it is desirable to provide connecting members that are likely to form these singular point states.

From this point of view, as a state in which regions a, b, and c shown in FIGS. 33A to 33D are stably formed, the structures shown in FIGS. 34A to 34C are considered. That is, in the structure shown in FIG. 34A , at the intersection position of the x-shaped trunk portion 28 of the electrode unit 26, a region a having a singularity point of intensity s=+1 is formed, and the slit 34 at the top of the figure On the top, a region c of singular points with intensities arranged in the order of s=-1, +1, -1 is formed, and on the slit 34 below the figure, a region b with singular points of intensities of s=-1 is formed. In addition, in the structure shown in FIG. 34B , at the intersection position of the X-shaped trunk portion 28 of the electrode unit 26, a region a having a singularity point of intensity s=+1 is formed, and the upper and lower slits 34 in the figure, 34, a region b with a singular point of intensity s=-1 is formed. Furthermore, in the structure shown in FIG. 34C , at the intersection position of the X-shaped trunk portion 28 of the electrode unit 26, a region a having a singular point of intensity s=+1 is formed, and the upper and lower slits in the figure On both 34 and 34, a region c where singular points of intensities s=-1, +1, and -1 are arranged in the order is formed.

In order to prevent the singular point from moving from the respective positions shown in FIGS. 34A to 34C , it is necessary to provide a singular point control unit for fixing the singular point. The structure and arrangement position of the singular point control unit will be described later with a specific embodiment. By installing the singular point control unit, it is possible to reduce the large movement of the singular point even when impacted by finger pressure or the like. Furthermore, the crystal domain boundary can be stably formed, and the crystal domains will not be connected across the crystal domain boundary. In this way, large disorder of liquid crystal orientation can be reduced, and color unevenness in display can be improved.

35A to 35B show the second principle of stable orientation according to this embodiment. As shown in FIG. 35A , in this principle, a linear vertical alignment control unit 200 for vertically aligning liquid crystal molecules 1 cm along a line is provided at a specific position in the crystal domain boundary. Furthermore, as shown in FIG. 35B , a linear vertical alignment control portion 202 for vertically aligning liquid crystal molecules 1 cm in a linear shape is provided at a specific position in the crystal domain boundary. The vertical orientation control parts 200, 202 also have the same effect as the singular point control part described in the above-mentioned first principle, and can prevent the crystal domains from being connected across the crystal domain boundaries, and can reduce the large loss of liquid crystal orientation. Disturbance, improvement of color spots. In addition, liquid crystal molecules are vertically aligned at the singular point, and in a broad sense, the singular point control unit can be considered to be included in the vertical alignment control unit.

In addition, in order to realize a more stable orientation, the linear vertical orientation control units 200 and 202 shown in the second principle are more effective than the method of controlling singular points mainly using the first principle. This is because control with wires can span a wider area than control with trigger points, inhibiting domains from bonding together. On the other hand, since the controlled vertical alignment area is completely black, if the vertical alignment control sections 200 and 202 have more areas, the brightness will be reduced. Therefore, when the brightness is important, it is better to control the singularity with points as shown in the first principle.

Next, the substrate for liquid crystal display according to this embodiment and the liquid crystal display device having the same will be specifically described using Examples 3-1 to 3-11.

(Example 3-1)

This embodiment will be described using FIGS. 36A to 36C. In this embodiment, as shown in FIGS. 36A to 36C , the singular point control units 400 a to 400 f , 402 , and 404 described in the first principle are formed on the side of the TFT substrate 2 where the pixel electrodes 16 are formed. In the arrangement example shown in FIG. 36A , singular point control units 400 a to 400 f are formed as insulating protrusion-shaped structures with substantially square bottoms at the vertices on the outer circumference of each electrode unit 26 and on the connection electrodes 36 . By arranging the singular point control units 400a to 400f in this way, it is possible to arrange the singular point (region a) with the intensity s=+1 at the intersection position of the X-shaped trunk portion 28 of the electrode unit 26 .

In the arrangement example shown in FIG. 36B , the singular point control unit 402 is formed as a rectangular insulating protrusion-shaped structure on the slit 34 between the electrode units 26, and the longitudinal direction of the bottom surface is the same as the length of the slit 34. The sides are in the same direction. The singular point control part (protrusion-shaped structure) 402 is a linear protrusion with a broken center. By disposing the singular point control unit 402 , the singular point (region b) having the intensity s=−1 can be disposed approximately at the center of the slit 34 between the electrode units 26 .

In the configuration example shown in FIG. 36C , the singular point control unit 404 is formed as a rectangular insulating protrusion-shaped structure on the slit 34 between the electrode units 26, and the longitudinal direction of the bottom surface is the same as the length of the slit 34. The sides are in the same direction. The singular point control part (protrusion-shaped structure) 404 is a linear protrusion disconnected on the two connection electrodes 36 , 36 . Singular points (region c) arranged in the order of intensities s=−1, +1, −1 can be arranged on the slits 34 between the electrode units 26 by the arrangement of the singular point control unit 404 .

Next, a method of manufacturing the LCD of this embodiment will be briefly described.

The TFT substrate 2 is the substrate for a liquid crystal display device shown in FIGS. 1 and 2 similar to the substrates described in the first and second embodiments, and OA-2 (manufactured by NEC Glass) with a substrate thickness of 0.7 mm was used. Although not shown in FIGS. 36A to 36C , on the TFT substrate 2 , in addition to the pixel electrodes 16 , TFTs 10 and bus lines 12 , 14 are formed. The pixel electrode 16 is formed by combining the same plurality of electrode units 26 as in FIG. 26A. The line width db of the branch portion 30 of the electrode unit 26 is 3 μm, and the width ds of the space 32 is 3 μm. The arrangement of pixel electrodes, TFTs, and bus lines composed of a plurality of electrode units is subject to FIG. 30 . That is, in FIGS. 36A to 36C , an example in which two electrode units are arranged is shown, but on an actual TFT substrate, three electrode units are arranged in one pixel.

After applying a photosensitive resin on the TFT substrate 2, patterning is performed by a photolithography process to form insulating layers constituting the singular point control portions 400a to 400f, 402, and 404 at the positions shown in FIGS. 36A to 36C. Sexual convexity. As the photosensitive resin, an acrylic material manufactured by JSR was used. The shape of the bottom of the singular point control parts 400a to 400f is a square with a length and width of 10 μm. The shape of the bottom surface of the singular point control unit 402 is two rectangles with a length of 10 μm and a width of 30 μm. The shape of the bottom surface of the singularity point control unit 404 is a square whose two ends are 10 μm in length and width, and a rectangle whose central part is 10 μm in length and 40 μm in width. The heights of the convex portions were all about 1.5 μm.

On the opposing substrate, an opposing electrode is formed. In addition, color filters may be provided on any one of the substrates. Next, a vertical alignment film is applied on these TFT substrates and the counter substrate. As the material of the orientation film, a polyimide material manufactured by JSR can be used. Next, the two substrates are pasted together through a spacer to form a blank cell. As the separator material, a resin separator manufactured by Sumitomo Fine Chemicals (manufactured by Sumitomo Fine Chemicals) can be used. The spacer diameter is 4 μm. In addition, a protrusion having a height equal to a cell gap may be formed using a material for forming the singular point control portion so as to function as a spacer. By doing so, it is not necessary to additionally scatter bead spacers, or otherwise form resin spacers.

Liquid crystals are injected into empty cells using a vacuum injection method. As the liquid crystal material, a material with negative dielectric anisotropy produced by Merck (Merta) can be used. A voltage is applied to the liquid crystal panel obtained in this way, and its orientation state is observed, and it can be seen that the positions shown by ● (black circles) and ○ (white circles) in the figure are formed with intensity s=+1, s=-1 Singularity of the oriented vector. Furthermore, when the liquid crystal panel is pressed with a finger to receive an impact, although the state of the crystal domains at the singularity point and its surroundings undergoes some changes immediately after the finger pressure, it will immediately return to the orientation state before the finger pressure. At the same time, no display stains were observed.

(Example 3-2)

This embodiment will be described using FIGS. 37A to 37C. In this embodiment, as shown in FIG. 37A, FIG. 37B, and FIG. 37C, singular point control units 406, 408, and 410 described using the first principle are formed on the counter substrate side disposed opposite to the TFT substrate. In the arrangement example shown in FIG. 37A , the singular point control unit 406 is formed as an insulating protrusion-shaped structure with a substantially square bottom on the counter substrate side at the intersection of the trunk parts 28 of each electrode unit 26 . By arranging the singular point control unit 406 in this way, the singular point (region a) having the intensity s=+1 can be arranged at the intersection position of the X-shaped trunk portion 28 of the electrode unit 26 .

In the arrangement example shown in FIG. 37B , the singular point control unit 408 is located on the counter substrate, and is formed as a square insulating protrusion-shaped structure approximately at the center of the slit 34 between the electrode units 26 . By disposing the singular point control unit 408 , the singular point (region b) with the intensity s=−1 can be disposed approximately at the center of the slit 34 between the electrode units 26 .

In the arrangement example shown in FIG. 37C , the singular point control unit 410 is located on the opposite substrate, and is an insulating protrusion-shaped structure with a square bottom, and is formed on the connection electrodes 36 on both sides of the slit 34 between the electrode units 26. , 36 above. By disposing the singular point control unit 410 , the singular points (region c) arranged in the order of intensities s=−1, +1, −1 can be disposed on the slits 34 between the electrode units 26 .

In addition, the size of each of the singular point control units 406, 408, and 410 is basically a square with a side length of 10 μm. Also, the same effect can be obtained by providing an electrode-removed portion corresponding to a convex pattern on the counter electrode instead of forming an insulating convex portion.

Apply a voltage to the liquid crystal panel made according to the present embodiment, and observe its orientation state as can be seen, in the figure the positions represented by ● (black circle) and ○ (white circle) respectively form an intensity of s=+1 , the singular point of the orientation vector of s=-1. When you press the liquid crystal panel with your fingers to make it impact, after the finger pressure, although there are some changes in the singular point and the surrounding crystal domain state immediately, it will immediately return to the orientation state before the finger pressure, and at the same time No display stains were observed.

Fig. 38 shows a specific structural example in Embodiment 3-1. Fig. 38 shows three pixels connected in the left-right direction in the figure and the planar structure of their vicinity. Each pixel has a substantially rectangular shape. Each pixel has a pixel electrode 16 that sandwiches a storage capacitor bus line 18 that traverses approximately the center of the pixel, and is formed of electrode units 26 that have three rows and two columns above and below. The electrode unit 26 of FIG. 38 is a combination of the electrode units 26 shown in FIGS. 13 and 19 . The connection electrode 36 is formed on the drain bus line 14 side. On the side of the substrate having the connection electrodes 36, a singular point control portion 410' formed of an insulating protrusion-shaped structure is formed. It is equivalent to removing one of the structures 402 in FIG. 36B. With such a structure, it is also possible to arrange the singularity point (region b) where the intensity s=−1 is approximately in the center between the electrode units 26 .

Fig. 39 shows another modified example of this embodiment. The pixel shown in FIG. 39 has line-symmetrical electrode units 26, 26' substantially sandwiching a central slit 34 therebetween. On the left side in the figure of the slit 34, a connection electrode 36 for connecting the electrode units 26, 26' is formed. On the opposite substrate side corresponding to the trunk portion 28 and the connection electrode 36, a singular point control portion 410″ made of an insulating protrusion-like structure is formed. With such a structure, the singular point ( Region b) is arranged on the connection electrode 36 of the slit 34 between the electrode units 26, 26', and the singular point with intensity s=+1 is arranged in the position where the structure crosses the electrode (in this figure, diagonally across in the location).

(Example 3-3)

This embodiment will be described using FIGS. 40A to 40C. In this embodiment, as shown in FIGS. 40A, 40B, and 40C, singular point control portions 412, 414, and 416 made of conductive protrusion-shaped structures are formed on the TFT substrate side. In the arrangement example shown in FIG. 40A , an insulating protrusion-shaped structure whose bottom surface is substantially square is formed in the lower layer at the intersecting positions of the trunk parts 28 of the electrode units 26 . The insulating protruding structure uses the same photosensitive material as in Example 3-1. In addition, when forming the TFT, by selectively leaving the insulating layer and the wiring layer stacked on the TFT substrate at the position where the protrusion is formed, an insulating protrusion-shaped structure can also be formed. Thus, the singular point control part 412 of the conductive protrusion-shaped structure that is convexly expanded at the intersection of the electrode main body 28 is formed. By arranging the singular point control part 412 in this way, the singular point (region a) Arranged at the intersection position of the X-shaped trunk portion 28 of the electrode unit 26 .

In the configuration example shown in FIG. 40B , the singular point control unit 414 is located on the TFT substrate, and an insulating protrusion-shaped structure with a substantially square bottom is formed on the lower layer of the central portion of the slit 34 between the electrode units 26. Here, the electrode branch portion 30 near the slit 34 is formed as a protrusion-shaped singular point control portion 414 . By disposing the singular point control unit 414 , the singular point (region b) having the intensity s=−1 can be disposed approximately at the center of the slit 34 between the electrode units 26 .

In the configuration example shown in FIG. 40C , the singular point control unit 416 is located on the opposite substrate, and the lower layer of the connecting electrodes 36 and 36 on both sides of the slit 34 between the electrode units 26 forms an insulating layer with a substantially square bottom surface. Thereby, the singular point control part 416 in which the connection electrode 36 is a protrusion is formed. By disposing the singular point control unit 416 , the singular points (region c) arranged in the order of intensities s=−1, +1, −1 can be disposed on the slits 34 between the electrode units 26 .

In addition, the size of each singular point control unit 412 , 414 , 416 is a square with a side length of about 10 μm, and a height of about 1.5 μm.

Apply a voltage to the liquid crystal panel made according to this embodiment, and observe its orientation state, it can be seen that orientation vectors with strengths of s=+1 and s=-1 are formed at the positions indicated by ● and ○ marks in the figure singular point. Furthermore, when the liquid crystal panel is pressed with a finger to receive an impact, although the state of the crystal domains at the singular point and its surroundings undergoes some changes immediately after the finger pressure, it will immediately return to the orientation state before the finger pressure, and at the same time No display stains were observed, either.

(Example 3-4)

This embodiment will be described using FIGS. 41A to 41C. In this embodiment, as shown in FIGS. 41A, 41B, and 41C, singular point control portions 418a to 418f, 420, and 422 made of conductive protrusion-like structures are formed on the counter substrate side. In the arrangement example shown in FIG. 41A, the singular point control units 418a to 418f are formed at the positions of vertices on the outer periphery of each electrode unit 26 and the lower layer of the counter electrode at the position facing the connection electrode 36, and the bottom surface is substantially square (sides). An insulating protruding structure with a length of about 10 μm and a height of about 1.5 μm. The insulating protruding structure uses the same photosensitive material as in Example 3-1. In this way, a conductive protrusion-shaped structure in which the counter electrode is convexly formed is formed. By arranging these conductive protrusion-shaped structures as the singular point control parts 418a to 418f, it is possible to arrange the singular point (region a) with the intensity s=+1 at the intersection of the X-shaped main part 28 of the electrode unit 26. position.

In the arrangement example shown in FIG. 41B , the singular point control unit 420 is a conductive protrusion-shaped structure with a square bottom (about 10 μm in side length and about 1.5 μm in height), and is formed on both sides facing the slit 34, respectively. The positions of the two connection electrodes 36, 36 on the side. By disposing the singular point control unit 420 , the singular point (region b) with the intensity s=−1 can be disposed approximately at the center of the slit 34 between the electrode units 26 .

In the configuration example shown in FIG. 41C , the singular point control unit 422 is a rectangle whose bottom surface is in the same direction as the longitudinal direction of the slit 34 (the side length is about 10 μm, the central part is 10 μm×40 μm, and the height is about 1.5 μm). μm) conductive protrusion-like structures are formed on the counter substrate above the slits 34 between the electrode units 26 . The singular point control unit 422 has a shape of a linear protrusion disconnected at a position toward the two connection electrodes 36 , 36 . By disposing the singular point control unit 422 , the singular points (region c) arranged in the order of intensities s=−1, +1, −1 can be disposed on the slits 34 between the electrode units 26 .

Apply a voltage to the obtained liquid crystal panel, and observe its orientation state, and it can be seen that the positions indicated by ● (black circle) and ○ (white circle) in the figure are formed respectively with intensities of s=+1 and s=-1. Singularity of the oriented vector. Furthermore, when the liquid crystal panel is pressed with a finger to receive an impact, although the state of the crystal domains at the singular point and its surroundings will change somewhat immediately after the finger pressure, it will immediately return to the orientation state before the finger pressure. At the same time, no display stains were observed.

(Example 3-5)

This embodiment will be described using FIGS. 42A to 42C. In this embodiment, as shown in FIGS. 42A and 42B , singular point control portions 424 and 426 made of an insulating concave structure are formed on the TFT substrate side. In the arrangement example shown in FIG. 42 , the singular point control unit 424 is formed approximately in the center of the slit 34 as a concave structure with a square bottom (about 10 μm in side length and about 1 μm in depth). By disposing the singular point control unit 424 , the singular point (region b) having the intensity s=−1 can be disposed approximately at the center of the slit 34 between the electrode units 26 .

In the arrangement example shown in FIG. 42B , the singular point control unit 426 is formed below the connection electrode 36 as a concave structure with a square bottom (about 10 μm in side length and about 1 μm in depth). By disposing the singular point control unit 426 , the singular points (area c) arranged in the order of intensities s=−1, +1, −1 can be disposed on the slit 34 between the electrode units 26 .

In addition, the concave portion is obtained by applying the above-mentioned photosensitive material on the entire substrate surface, and then removing the photosensitive material only at the position of the concave portion. In addition, when forming the TFT on the substrate, holes may be formed in the laminated insulating layer and wiring layer to form the concave portion.

Apply a voltage to the obtained liquid crystal panel, and observe its orientation state, and it can be seen that the positions indicated by ● (black circle) and ○ (white circle) in the figure are formed respectively with intensities of s=+1 and s=-1. Singularity of the oriented vector. Furthermore, when the liquid crystal panel is pressed with a finger to make it receive an impact, although the state of the crystal domains at the singularity point and its surroundings will undergo some changes immediately after the finger pressure, it will immediately return to the orientation state before the finger pressure. At the same time, no display stains were observed.

(Example 3-6)

This embodiment will be described using FIGS. 43A to 43C. In this embodiment, as shown in FIGS. 43A, 43B, and 43C, singular point control portions 428a to 428f, 430, and 432 made of conductive concave structures are formed on the TFT substrate side. In the arrangement example shown in FIG. 43A, the singular point control parts 428a to 428f are formed as conductive concave-shaped structures with a square bottom (about 10 μm in length and about 1 μm in depth), and are respectively formed on the outer periphery of each electrode unit 26. Each apex position is connected to the lower layer of the electrode 36 . By arranging the singular point control units 428a to 428f, it is possible to arrange the singular point (region a) with the intensity s=+1 at the intersection position of the X-shaped trunk portion 28 of the electrode unit 26 .

In the arrangement example shown in FIG. 43B , the singular point control unit 430 is a rectangular conductive concave structure whose bottom surface's longitudinal direction coincides with the longitudinal direction of the slit 34, and is formed in the slit 34 between the electrode units 26. superior. The singular point control unit 430 is formed in a linear shape with a disconnected central portion. By disposing the singular point control unit 430 , the singular point (region b) with the intensity s=−1 can be disposed approximately at the center of the slit 34 between the electrode units 26 .

In the arrangement example shown in FIG. 43C , the singular point control unit 432 is a rectangle whose bottom surface is in the same longitudinal direction as the slit 34 (the two sides are a square with a side length of about 10 μm, and the central part is 10 μm×40 μm). , with a depth of about 1 μm), formed on the slits 34 between the electrode units 26 . The singular point control unit 432 has a linear shape disconnected on the two connection electrodes 36 , 36 . By disposing the singular point control unit 432 , the singular points (region c) arranged in the order of intensities s=−1, +1, −1 can be disposed on the slit 34 between the electrode units 26 .

In addition, the concave portion is obtained by applying the above-mentioned photosensitive material on the entire substrate surface, and then removing the photosensitive material only at the position of the concave portion. In addition, when the TFT is formed on the substrate, the recess may be formed by opening a hole in the laminated insulating layer or wiring layer.

Apply a voltage to the obtained liquid crystal panel, and observe its orientation state, and it can be seen that the positions indicated by ● (black circle) and ○ (white circle) in the figure are formed respectively with intensities of s=+1 and s=-1. Singularity of the oriented vector. Furthermore, when the liquid crystal panel is pressed with a finger to receive an impact, although the state of the crystal domains at the singular point and its surroundings will change somewhat immediately after the finger pressure, it will immediately return to the orientation state before the finger pressure. At the same time, no display stains were observed.

(Example 3-7)

This embodiment will be described using FIGS. 44A to 44C. In this embodiment, as shown in FIG. 44A, FIG. 44B, and FIG. 44C, the singular point control units 434, 436, and 438 described in the first principle are formed on the counter substrate side disposed opposite to the TFT substrate. In the arrangement example shown in FIG. 44A , the singular point control unit 434 is formed as a conductive concave structure with a substantially square bottom on the opposing substrate side at the intersection of the trunk parts 28 of the electrode units 26 . By arranging the singular point control unit 434 in this way, it is possible to arrange the singular point (region a) with the intensity s=+1 at the intersection position of the X-shaped trunk portion 28 of the electrode unit 26 .

In the arrangement example shown in FIG. 44B , the singular point control unit 436 is formed as a square conductive concave structure at the center of the slit 34 between the electrode units 26 on the counter substrate. By disposing the singular point control unit 436 , the singular point (region b) having the intensity s=−1 can be disposed approximately at the center of the slit 34 between the electrode units 26 .

In the arrangement example shown in FIG. 44C , the singular point control unit 438 is formed on the opposite substrate as a conductive concave structure with a square bottom surface on the connecting electrodes 36 and 36 on both sides of the slit 34 between the electrode units 26. above. By disposing the singular point control unit 438 , the singular points (region c) arranged in the order of intensities s=−1, +1, −1 can be disposed on the slits 34 between the electrode units 26 .

In addition, the concave portion is obtained by applying the above-mentioned photosensitive material on the entire substrate surface, and then removing the photosensitive material only at the position of the concave portion. Furthermore, the conductive recess can be formed by forming a counter electrode on the recess. The size of the concave portion was a square with a side length of about 10 μm and a depth of about 1 μm.

Apply a voltage to the liquid crystal panel made according to the present embodiment, and observe its orientation state, it can be seen that the singularities of the orientation vectors with strengths of s=+1 and s=-1 are formed respectively at the positions represented by ● and ○ marks in the figure point. Furthermore, when the liquid crystal panel is pressed with a finger to receive an impact, although the state of the crystal domains at the singular point and its surroundings undergoes some changes immediately after the finger pressure, it will immediately return to the orientation state before the finger pressure, and at the same time No display stains were observed, either.

(Example 3-8)

This embodiment will be described using FIGS. 45A to 46D. A characteristic point of the singular point control unit according to the present embodiment is that the concave or convex structure is composed of both an insulating portion and a conductive portion. 45A to 45C show examples of such feature points. 45A to 45C show schematic cross-sectional views when the LCD panel is cut along a direction perpendicular to the substrate surface. FIG. 45A shows a state in which a liquid crystal layer 48 is sealed between the TFT substrate 2 and the CF substrate 4, wherein the TFT substrate 2 is on the glass substrate 52. A protective film 56 is formed, and a common electrode 58 is formed on the glass substrate 53 of the CF substrate 4 .

A singular point control portion 440 of an insulating concave structure is formed on the protective film 56 on the TFT substrate 2 side. A vertical alignment film (not shown) is formed on the liquid crystal layer 48 side of both substrates 2 and 4 . Therefore, imitating the concave shape of the singular point control part 440, the liquid crystal molecules 1 cm on the singular point control part 440 will converge and tilt slightly toward the CF substrate 4 side even when no voltage is applied, and will further tilt toward the direction when a voltage is applied. tilt.

On the other hand, in FIG. 45B , on the protective film 56 on the TFT substrate 2 side, a singular point control portion 442 of a conductive concave structure on which a part of the pixel electrode 16 is formed is formed. Conductive film 16'. Therefore, when a voltage is applied, since lines of electric force E having the shape shown in the figure are generated, 1 cm of liquid crystal molecules on the singular point control portion 442 diverge and incline toward the CF substrate 4 side.

FIG. 45C shows control by a combination of insulating recesses and conductive recesses. As shown in FIG. 45A and FIG. 45B, a singular point is formed on both the insulating concave portion and the conductive concave portion, and the liquid crystal molecules are oriented 1 cm centering on the singular point, but the direction of orientation control on the insulating concave portion and the conductive concave portion opposite of each other. Here, as shown in FIG. 45C , by forming the singular point control portion 444 in which the conductive film 16 ′ is formed only in half of the concave portion, it is possible to control the liquid crystal molecules in the same direction by 1 cm in the concave portion.

46A to 46D show states in which the singular point control unit 444 shown in FIG. 45C is applied to an actual electrode unit 26 . In the example shown in FIG. 46A and FIG. 46B showing the cross section along the line X-X in FIG. 46A, the singular point control portion 444 is formed as a concave structure whose bottom surface is a square (about 10 μm in length and about 1 μm in depth). It is arranged such that about half of the right side of the concave portion (outside the pixel at the center of the concave portion) is covered with the connection electrode 36 . By arranging the singular point control unit 444 in this way, it is possible to reliably form a singular point with the intensity s=−1. Therefore, singular points (region c) arranged in the order of intensities s=−1, +1, −1 can be arranged on the slit 34 between the electrode units 26 .

In the example shown in FIG. 46C and FIG. 46D showing the cross section along the Y-Y line in FIG. 46C, the singular point control portion 446 is formed as a concave structure whose bottom surface is a square (about 10 μm in length and about 1 μm in depth). It is arranged such that about half of the left side of the concave portion (the inner side of the pixel in the center of the concave portion) is covered with the connection electrode 36 . By disposing the singular point control unit 446 in this way, no singular point can be formed on the connection electrode 36 , and the singular point (region b) with the intensity s=−1 is fixed at approximately the center of the slit 34 .

(Example 3-9)

This embodiment will be described using FIGS. 47A to 47C. 47A shows the state seen from the normal direction of the substrate surface, FIG. 47B shows a cross-sectional view along line A-A of FIG. 47A, and FIG. 47C shows a cross-sectional view along line B-B of FIG. 47A. As shown in FIG. 47A to FIG. 47C , a concave pattern of the singular point control unit 448 of this embodiment has two parts, an insulating part and a conductive part. In the portion where the branched portions (fine electrode pattern groups) 30 extending in four directions up, down, left, and right are connected by the trunk portion (x-shaped electrode) 28, a concave portion is provided at the center of the x-shape. Thus, as shown in FIGS. 47B and 47C , the concave portion has two parts, an insulating part and a conductive part. In the past, the direction of the orientation control of the insulating concave portion and the conductive concave portion as shown in FIG. 45A and FIG. The orientation state of the singular point (region a) with intensity s=+1. This is because this portion is originally stable in the orientation state of the region a, and tends to have a tendency to control the conductive unevenness compared to the insulating unevenness under the same width and height conditions.

(Example 3-10)

This embodiment will be described using FIG. 48 . This embodiment utilizes the second principle of stabilizing orientation described with reference to FIGS. 35A and 35B. As shown in FIG. 48, instead of forming a convex portion or a concave portion, a vertical orientation control portion 202 having an electrode removal portion that is the width of the slit 34 between the electrode units 26 (the removal width is a ) formed after expansion. As a result, 1 cm of liquid crystal molecules aligned vertically in a line shape are stably formed in the slit 34 .

Furthermore, when the liquid crystal panel is pressed with a finger to receive an impact, the state of the crystal domains in the vertical alignment control portion 202 and its surroundings immediately after the finger pressure will return to the alignment state before the finger pressure, although some changes have taken place. , corresponding to this, no color spots can be observed. Although the width a of the vertical orientation control portion 202 is preferably wider, if it is too wide, the light transmittance will decrease. Therefore, it is at least wider than the thickness of the cell, preferably more than twice the thickness of the cell. Here, the removal width a of the vertical alignment control portion 202 was set to 12 μm for a cell thickness of 4 μm. In addition, when the removal width a was 4 to 6 μm, staining occurred when finger pressure was applied, and the alignment state was also unstable.

(Example 3-11)

This embodiment will be described using FIG. 49A and FIG. 49B. This embodiment also utilizes the second principle. No convex portion or concave portion is formed, and a vertical alignment control electrode independent of the pixel electrode 16 is newly provided on at least a part of the slit 34 between the electrode units 26 to form the vertical alignment control portion 204 . FIG. 49A shows an example in which the vertical orientation control portion 204 is formed over the entire area of the slit 34 in the longitudinal direction. FIG. 49B shows an example in which the vertical alignment control portion 206 is formed on two regions of the two connection electrodes 36 spanning the slit 34 .

The electrodes for vertical orientation control of these vertical orientation control sections 204 and 206 can be applied with a potential equal to that of the counter electrode. In this way, since no voltage is applied between the vertical alignment control electrodes and the counter electrode of the vertical alignment control portions 204, 206, the liquid crystal molecules on the vertical alignment control portions 204, 206 can be stably vertically aligned by 1 cm. In addition, on the two connection electrodes 36, a singularity point of intensity s=−1 is formed.

On a liquid crystal panel driven by a switching element such as a TFT, electrodes for vertical orientation control of the vertical orientation control sections 204 and 206 can be formed using a storage capacitor bus. In this way, the vertical orientation control parts 204 and 206 can be formed at the same time when the storage capacitor bus is formed. Since there is no need to set up other processes for forming the vertical orientation control parts 204 and 206, it has the advantages of improving the yield and suppressing the manufacturing cost.

50A and 50B show a schematic configuration when the electrodes of the vertical alignment control sections 204 and 206 are formed using the storage capacitor bus 18 (illustration of TFTs and the like are omitted). In FIG. 50A , connection electrode 36 is arranged near drain bus line 14 (periphery of the pixel region), and in FIG. 50B , connection electrode 36 is arranged approximately in the center of the outer periphery of electrode unit 26 . In both figures, the wiring is branched from the storage capacitor bus line 18, extends along the direction of the drain bus line 14, that is, the vertical direction in the figure, and is connected to the vertical orientation control parts 204, 206 formed on the slit 34. electrode. In addition, FIG. 50A and FIG. 50B also show the arrangement positions of the dot-shaped protrusions 210 formed on the counter substrate side to enhance orientation regulation.

51A to 51G show specific structural examples in this embodiment. 51A to 51E show the planar structure of one pixel and its vicinity. Each pixel has an approximately rectangular outer shape with a side length of 86 μm×260 μm. Each pixel has a pixel electrode 16 formed of electrode units 26 with three rows and two columns above and below, sandwiching a storage capacitor bus line 18 across the center of the pixel. The main parts 28 of the electrode units 26 in FIGS. 51A and 51E intersect in an X shape, and the main parts 28 of the electrode units 26 in FIGS. 51B to 51D intersect in a cross shape. 51A, 51C, and 51E are formed on the drain bus line 14 side, and connection electrodes 36 in FIGS.

As shown in each figure, the wiring branches from the storage capacitor bus line 18 and extends along the direction of the drain bus line 14, that is, the vertical direction in the figure, forming an H-shaped storage capacitor wiring on each pixel. The vertical alignment control electrodes of the vertical alignment control section 206 drawn from the H-type storage capacitor wiring to each slit 34 are formed. In addition, FIGS. 51A to 51G also show the arrangement positions of the dot-like protrusions 210 formed on the counter substrate side for enhancing orientation control. The dot-shaped protrusion 210 is formed approximately at the center of each electrode unit 26 . According to the pixel structure shown in each of FIG. 51A to FIG. 51G, since no voltage is applied between the H-type storage capacitor wiring and the vertical alignment control electrode and the counter electrode of the vertical alignment control section 206, the H The liquid crystal molecules on the wiring of the type storage capacitor and the vertical orientation control unit 206 are stably vertically aligned within 1 cm. Furthermore, a singular point of intensity s=−1 is formed on the two connecting electrodes 36 .

As described above, according to the present embodiment, even when some impact may be caused by pressing the liquid crystal panel with a finger etc. in actual use, the liquid crystal display device whose alignment state is stable and does not cause display defects such as color unevenness can be realized.

(fourth embodiment)

Next, a substrate for a liquid crystal display device and a liquid crystal display device having the substrate according to a fourth embodiment of the present invention will be described. The present embodiment relates to a method for reliably regulating the orientation of a vertical alignment type liquid crystal without providing an alignment regulating structure on the counter substrate side.

In an MVA-type LCD, a contrast ratio of 10 or higher can be obtained when the viewing angle in the up, down, left, and right directions is 80° during monochrome display. However, it is necessary to form alignment control linear protrusions with resin or the like on at least one of the substrate sides. Therefore, the manufacturing yield may be correspondingly reduced due to an additional process of forming the linear protrusions.

52A and 52B show connection examples between electrode units. FIG. 52A shows that the square electrode units 526 are arranged in a matrix structure of five vertically and three horizontally through the slits 534 . Between adjacent electrode units 526 , electrical connections are made with connection electrodes 536 extending approximately from the midpoint of one side of the electrode units 526 . FIG. 52B shows a structure in which apex corners of adjacent outer peripheries of a plurality of electrode units 526 arranged in the same arrangement as in FIG. 52A are connected by connection electrodes 536 .

As shown by the straight arrows in the two figures, the structures shown in FIG. 52A and FIG. 52B connect a plurality of electrode units 526 together with a straight line through connecting electrodes 536 . Therefore, when the formation positions of the singular points of intensity s=+1 respectively formed on a plurality of electrode units 526 arranged in a straight line become unstable, there is a possibility that the singular points move the connection electrode 536 as a path greatly. As the value becomes larger, the probability that misalignment spreads to the entire pixel becomes considerably higher.

The purpose of the present embodiment is to satisfy the following conditions and align liquid crystal molecules obliquely in a plurality of desired directions when a voltage is applied. The conditions are: (1) do not form a dam-like structure using a resin material, etc.; (2) do not apply an orientation limiting force such as rubbing treatment to the orientation film (that is, only align the liquid crystal molecules in a direction perpendicular to the relative substrate); (3) The orientation direction is restricted only by the pixel electrode structure on the TFT substrate side.

In order to achieve this, in the present embodiment, the pixel electrode provided on the TFT substrate side has the following shape. First, the pixel electrode of each pixel combines a plurality of electrode units forming a rectangle or the like. Next, connecting electrodes for electrically connecting the plurality of electrode units are arranged as described below.

A plurality of electrode units adjacent to each other are separated by slits provided along the outer peripheral sides of the electrode units. On one side of the outer periphery of the electrode unit, a connection electrode is formed only at any one of both end portions of the side. When the connection electrodes are provided on a plurality of sides of the outer periphery of the electrode unit, the following pixel pattern is used, that is, the connection electrodes are provided only at the end of one of the corners where two adjacent sides intersect. When a plurality of electrode units are arranged in this way, a pixel electrode pattern such as that shown in FIG. 53 is formed (first method).

In addition, the shape of the electrode unit may be configured such that, starting from a part of each side of the outer periphery of the electrode unit, a long and thin space is formed toward the adjacent side to the vicinity of the side. The intervals provided starting from each side are set toward the direction of the adjacent side so that the center of the electrode unit is the axis and have the same rotation direction. It doesn't matter whether the direction of rotation is clockwise or counterclockwise. In the same manner as in the above-mentioned first method, the electrode units designed in this way are adjoined with a slit therebetween. Connecting electrodes are provided on the outer peripheral end to electrically connect adjacent electrode units (second method).

In addition, the width of the slit dividing the plurality of electrode units is 6 μm or more and the length is 100 μm or less, and the width of the connecting electrode electrically connecting the plurality of electrode units is 5 μm or less.

Utilization of this embodiment provides the following effects on the LCD manufacturing process.

(1) Since there is no need to add a structure on the opposite substrate side, the step of forming the structure on the opposite substrate can be omitted.

(2) It is the pixel electrode pattern on the TFT substrate side that restricts the orientation of the liquid crystal molecules. Since this can be performed by the same steps as the usual step of forming the plate-like pixel electrode pattern, there is no need to add a new step.

(3) The alignment films formed on the two substrates are only coating and film-forming of the vertical alignment films, and there is no need for processes such as rubbing treatment or photo-alignment treatment to apply alignment limiting force.

According to the effects of (1) to (3), since the factor of reducing the yield due to the addition of steps is eliminated, the yield of manufacture can be improved as a result.

In addition, by configuring the pixel electrode structure of each pixel by the above-mentioned first or second method, the following effects are produced.

(4) With the first method, since there are only two electrode units connected along a straight line using one connecting electrode, even if the position of the singular point with intensity s=+1 is disturbed, the region of disordered orientation can be reduced.

(5) With the second method, since there are only two electrode units connected along a straight line using one connecting electrode, and since the area connected along a straight line with a connecting electrode is very short, even if the singular point with intensity s=+1 is disturbed , the region of disorientation can also be reduced.

(6) When the width of the slit located around the electrode unit is 6 μm or more, since the effect of the oblique electric field at the end of the electrode unit is enhanced, desired orientation can be achieved within the electrode unit. Conversely, when the width of the slit is narrower than this width, the effect of the oblique electric field becomes small, and orientation disorder occurs.

(7) The shorter the length of the slit around the electrode unit, the smaller the size of the electrode unit, and thus the effect of the oblique electric field at the end of the electrode unit can be enhanced. Although it is best to reduce the size of the electrode unit itself as much as possible, reducing the size of the electrode unit, on the contrary, means increasing the area of the slit portion, which will reduce the brightness. Therefore, the electrode unit must have an appropriate size, and its width is ideally about 40 μm. Therefore, the length of one slit can be up to 100 μm.

(8) When the width of the connecting electrode is too wide, the singular point with intensity s=+1 moves to the adjacent electrode unit, and the orientation becomes unstable. When the width is made to be 5 μm or less, since the singular point with the intensity s=+1 hardly moves, the orientation itself is quite stable.

In addition, when a pair of orthogonal λ/4 plates sandwiches the upper and lower sides of a liquid crystal panel produced by applying the substrate for a liquid crystal display device according to this embodiment, it is possible to eliminate the problem that occurs when only a linear polarizing plate is sandwiched. The disclination line generated on the boundary of the directional division part can increase the amount of light transmitted through the line portion, so that the overall brightness can be improved.

Hereinafter, the substrate for a liquid crystal display device according to this embodiment and the liquid crystal display device having the substrate will be specifically described using Examples 4-1 to 4-5.

(Example 4-1)

This embodiment will be described using FIG. 53 and FIG. 54 . FIG. 53 shows the arrangement relationship of the electrode units 26 arranged in a matrix of 5 rows and 4 columns and the connection electrodes 36 electrically connecting the electrode units 26 . In FIG. 53 , a plurality of electrode units 26 adjacent to each other are partitioned by slits 34 provided along the outer peripheral sides of the electrode units 26 . Connection electrodes 36 are formed at respective one end portions of the outer peripheral sides of the electrode unit 26 . At the corners where two adjacent sides of the electrode unit 26 intersect, the connection electrodes 36 are provided only at the ends of either side. According to such a structure, as shown by the arrow in FIG. 53, since there are only two electrode units 26 connected along a straight line using one connection electrode 36, even when the position of the singular point with intensity s=+1 is disturbed, the Reduced areas of disorientation.

FIG. 54 shows a pixel formed by the arrangement relationship between the electrode unit 26 and the connection electrode 36 shown in FIG. 53 . The size of the pixel pitch (long side direction of the pixel) extending in the direction of the drain bus line 14 is 300 μm, and the size of the pixel pitch extending in the direction of the gate bus line 12 is 100 μm. Drain bus lines 14 and gate bus lines 12 having a width of 7 μm are formed on the TFT substrate 2 , and pixel electrodes 16 are formed of ITO at positions 8 μm apart from them. That is, the width of the region where the pixel electrode 16 is formed is 77 μm. The pattern shape of the pixel electrode 16 will be described later. TFT 10 is formed near the intersection of drain bus line 14 and gate bus line 12 of each pixel.

The pixel electrode 16 includes a plurality of electrode units 26 . One electrode unit 26 is a square plate-shaped close-contact electrode with an outer peripheral shape of 19 μm×19 μm. Between adjacent electrode units 26, slits 34 having a width of 6 μm are arranged. A connection electrode 36 for connecting electrode units 26 adjacent to each other is formed at one end portion of a side of the square electrode unit 26 . The connection electrode 36 is not formed at the other end of the side. In addition, the connection electrodes 36 are not formed at the ends of adjacent sides of the corners forming the connection electrodes 36 . That is, one connection electrode 36 is formed at each corner of the square, and four connection electrodes 36 are formed whose outer peripheral portion has a pinwheel shape as a whole. In addition, the width of the connection electrode 36 is 3.5 μm. In this way, the electrode units 26 forming the connection electrodes 36 are adjacent to each other in a state where the connection electrodes 36 are connected to each other. Slits 34 with a width of 6 μm are formed between adjacent electrode units 26 . The positional relationship of the adjacent slits 34 is such that the end of one slit 34 is positioned at the center of the other slit 34 in the longitudinal direction across the connection electrode 36 , and the distance between the adjacent slits 34 The long-side directions are perpendicular to each other.

In addition, the pixel electrode 16 is connected to the source of the TFT 10 through a contact hole (not shown) formed on the insulating layer. Therefore, it is necessary to have a margin required for forming a contact hole, so it is necessary to have a transparent electrode of a certain size in the connection region between the pixel electrode 16 and the source electrode. For this reason, only in this region, a square plate-shaped contact electrode with a side length of about 15 μm was provided.

In addition, the drain of the TFT 10 for an adjacent pixel is arranged below the pixel in the figure. Therefore, in order to prevent the occurrence of orientation disorder or crosstalk caused by the drain, the end of the pixel electrode 16 is set 7 μm away from the drain so that the pixel electrode 16 does not overlap the drain.

Further, on the CF substrate (counter substrate) 4 side, black matrices having a width of 23 μm are provided at a pitch of 300×100 μm in the direction of the drain bus lines 14 . Color filter (CF) layers of R, G, and B are formed in the openings, and a common electrode made of ITO is formed on the layers in a "plate shape" in close contact with each other. In addition, no pinwheel-shaped structure for orientation regulation is formed on the counter substrate 4 .

A vertical alignment film is formed on the two substrates, and the liquid crystal molecules are oriented in a direction perpendicular to the surface of the substrate (orientation film surface) in the state where no voltage is applied. The TFT substrate 2 and the TFT substrate 4 are pasted together with a predetermined cell gap, liquid crystal having negative dielectric anisotropy is injected, and then sealed.

Normally, when the liquid crystal panel configured in this way is driven, in one electrode unit 26 of the pixel electrode 16, directional division in approximately four directions from the ends (that is, the portion corresponding to the side) of the square toward the center can be realized. Since the size of one electrode unit 26 is smaller than 19 μm×19 μm, it is possible to increase the effect of the electric field at the edge of the pixel and to increase the directional control force. In addition, through the disposition of the slit 34 in the pixel electrode 16, since the distance connected by a straight line through the connecting electrode 36 can be shortened, it is difficult to cause poor alignment to connect the alignment regions between adjacent electrode units 26, even if Assuming such a situation occurs, it is also possible to prevent a decrease in display quality.

(Example 4-2)

This embodiment will be described using FIG. 55 . This embodiment has such a structure: Although the shape of the electrode unit 26 is the same as that shown in FIG. electrode 36. According to such a configuration, since the number of connections between adjacent electrode units 26 is reduced, the probability of misorientation caused by the movement of the singular point with intensity s=+1 can be further reduced.

(Example 4-3)

This embodiment will be described using FIG. 56 . Although the shape of the electrode unit 26 is the same as that shown in FIG. The connection electrodes 36 are provided only on two opposite sides of the outer periphery, and no connection electrodes are provided on the remaining two sides. With such a structure, since the number of connections between adjacent electrode units 26 is reduced, it is possible to further reduce the occurrence probability of misorientation due to the movement of the singular point of intensity s=+1.

(Example 4-4)

This embodiment will be described using FIGS. 57A to 58 . 57A shows the shape of one electrode unit 26 according to this embodiment, and FIG. 57B shows the arrangement relationship of electrode units 26 arranged in a matrix of 3 rows and 2 columns and connection electrodes 36 electrically connecting electrode units 26.

The electrode unit 26 is a square with an outer peripheral shape of 35 μm×35 μm. In one electrode unit 26, four spaces 33 each having a width of 6 μm are provided starting from a part of each side. The starting point of the space 33 is preferably a position close to the center of each side. Specifically, on one of the lower sides of the four sides of the square shown in FIG. 57A, a position about 14 μm from the right end is taken as a starting point, and an angle of 45° is formed with respect to the side, and the space 33 is directed toward the adjacent side. Extend in the direction of the edge on the right side. Since the electrode will be cut off if the space 33 is extended to the adjacent right side, it is necessary to keep the electrode corresponding to the side to which the space 33 extends. When such spaces 33 are provided on each side of the square, the shape of the electrode unit 26 shown in FIG. 57A is formed.

When two electrode units 26 of this structure are arranged along the direction of the gate bus line 12 and six are arranged along the direction of the drain bus line 14, the structure shown in FIG. 58 is obtained. The electrode units 26 adjacent to each other are separated by a slit 34 with a width of 7 μm. In each electrode unit 26 , a connection electrode 36 for electrically connecting each electrode unit 26 is provided at an end portion of the pixel electrode 16 . This is to shorten the length of the linear connection on the pixel electrode 16 . In this way, poor alignment that connects the alignment portions between adjacent electrode units 26 via the slit 34 is less likely to occur, and even if poor alignment occurs, degradation in display quality can be prevented.

(Example 4-5)

This embodiment will be described using Fig. 59 and Fig. 60 . In this embodiment, the pixel pitch (long side direction of the pixel) extending along the direction of the drain bus line 14 is 225 μm. On the other hand, the size of the pixel pitch extending in the direction of the gate bus line 12 is 75 μm. This is an example when the size of a pixel itself is small compared with Example 4-1 and Example 4-4.

Drain bus lines 14 and gate bus lines 12 having a width of 6 μm are formed on the TFT substrate 2 , and pixel electrodes 16 are formed of ITO at positions 7 μm away from them. That is, the width of the region where the pixel electrode 16 is formed is 55 μm. The pattern shape of the pixel electrode 16 will be described later. TFT 10 is formed near the intersection of drain bus line 14 and gate bus line 12 of each pixel.

The pixel electrode 16 includes a plurality of electrode units 26 . One electrode unit 26 is a square electrode having a peripheral shape of 24.5 μm×24.5 μm. Slits 34 with a width of 6 μm are arranged between adjacent electrode units 26 . A connection electrode 36 for connecting electrode units 26 adjacent to each other is formed at one end portion of a side of the square electrode unit 26 . In addition, the connection electrode 36 is not formed at the other end of the side, and the connection electrode is not formed at the end of the side adjacent to the corner at which the connection electrode 36 is formed. That is, the connection electrodes 36 are formed one at each of different corners of the square in a pinwheel shape. In addition, the width of the connection electrode 36 is 3.5 μm. In this way, the electrode units 26 forming the connection electrodes 36 are adjacent to each other in a state where the connection electrodes 36 are connected to each other. Slits 34 with a width of 6 μm are formed between adjacent electrode units 26 . The positional relationship of the adjacent slits 34 is arranged such that the end of one slit 34 is located at the center of the other slit 34 in the longitudinal direction across the connection electrode 36 , and the gap between adjacent slits 34 The long sides are perpendicular to each other.

Two electrode units 26 formed in this way are arranged in a horizontal direction (the direction in which the gate bus lines 12 extend) and six in a vertical direction (the direction in which the drain bus lines 14 extend). In order to align the storage capacitor bus 18 with the slit 34 formed when arranging the electrode units 26, it is not arranged at the center of the pixel, but is arranged at an upper or lower position. Specifically, a storage capacitor electrode 20 having a width of 20 μm is provided at a position about 150 μm away from the lower gate bus line 12 and about 75 μm away from the upper side gate bus line 12 as the center. With the storage capacitor electrode 18 as a boundary, 8 (=2×4) electrode units 26 are arranged in the lower opening region, and 4 (=2×2) electrode units 26 are arranged in the upper opening region. However, as in Example 4-1, part of the shape of the electrode unit 26 must be changed so that it does not overlap with the TFT region of an adjacent pixel.

In addition, the pixel electrode 16 is connected to the source of the TFT 10 through a contact hole (both not shown) formed on the insulating layer. Therefore, in order to form a contact hole, it is necessary to have a margin, and the connection region between the pixel electrode 16 and the source electrode must have a transparent electrode of a certain size. For this reason, only in this region, a square plate-shaped contact electrode with a side length of about 15 μm was provided.

In addition, drains of TFT 10 for adjacent pixels are disposed below the pixels in the figure. Therefore, in order to prevent the occurrence of orientation disorder or crosstalk caused by the drain, the end of the pixel electrode 16 is provided 7 μm away from the drain so that the pixel electrode 16 and the drain do not overlap.

Further, on the side of the CF substrate (counter substrate) 4 , black matrices with a width of 20 μm are provided at a pitch of 225 μm×75 μm along the direction of the drain bus lines 14 . Each of the CF layers of R, G, and B is formed in the opening, and a common electrode made of ITO is formed on the upper surface in a "plate shape" in close contact with each other. In addition, on the counter substrate 4, any bank-like structure for orientation regulation is not formed.

A vertical alignment film is formed on the two substrates, and the liquid crystal molecules are oriented in a direction perpendicular to the surface of the substrate (orientation film surface) in the state where no voltage is applied. The TFT substrate 2 and the counter substrate 4 are pasted with a predetermined cell gap, liquid crystal having negative dielectric anisotropy is injected, and then sealed.

When normally driving a liquid crystal panel configured in this way, in one electrode unit 26 of the pixel electrode 16, directional division in approximately four directions from the ends (that is, portions corresponding to sides) to the center of the square can be realized. Since the size of one electrode unit 26 is smaller than 24.5 μm×24.5 μm, it is possible to increase the effect of the electric field at the edge of the pixel and increase the directional control force. In addition, because the disposition of the slit 34 in the pixel electrode 16 can shorten the distance connected by a straight line through the connecting electrode 36, it is difficult to cause poor alignment that connects the alignment regions between adjacent electrode units 26, Even if such a case occurs, a reduction in display quality can be prevented.

FIG. 60 shows the pixel electrode 16 in which the electrode unit 26 in the pixel structure shown in FIG. 59 is changed to the shape shown in FIGS. 57A and 57B. In the structure of the pixel electrode 16 shown in FIG. 60, three electrode units 26 shown in FIGS. 57A and 57B are arranged in the vertical direction (the direction in which the drain bus lines 14 extend). In order to align the storage capacitor bus 18 with the slit 34 formed when arranging the electrode units 26 , it is not arranged at the center of the pixel, but at an upward or downward position. Two electrode units 26 are arranged in the lower opening region and one electrode unit 26 is arranged in the upper opening region with the storage capacitor bus line 18 as a boundary. However, as in Example 4-1, it is necessary to change a part of the shape of the electrode unit 26 so that it does not overlap with the TFT region of an adjacent pixel. In this way, poor alignment that connects alignment portions between adjacent electrode units 26 via the slit 34 is less likely to occur, and even if poor alignment occurs, degradation in display quality can be prevented.

According to the present embodiment as described above, only the process of forming the pattern of the pixel electrode can be used to apply the orientation control force, and since the occurrence of poor orientation can be reduced, it is possible to manufacture high-quality images with high yield and low cost. Quality LCDs. In addition, if circularly polarizing plates having optical axes perpendicular to each other are arranged on the front and back sides of the LCD panel of this embodiment, high-intensity display can be easily realized.

(fifth embodiment)

Next, a substrate for a liquid crystal display device and a liquid crystal display device having the substrate according to a fifth embodiment of the present invention will be described. As described in the fourth embodiment, the conventional MVA-LCD and ASV-LCD require a step of forming a bank-shaped resin pattern, which has a problem of lowering the yield. In addition, on the pixel electrode, when the movement of the liquid crystal occurs at the moment of switching from low grayscale to high grayscale, the singularity point with intensity s=+1 moves through the connecting electrodes electrically connecting the electrode patterns adjacent to each other, and sometimes occurs The phenomenon that fixes this state. This phenomenon is manifested as an afterimage.

In addition, when the surface of the liquid crystal panel is pressed with a finger, the liquid crystal molecules are physically pressed and tilted. In this case, the singular point with intensity s=+1 will also move, needless to say for the connected electrodes, even the singular point with intensity s=+1 will move across the slit between the electrode patterns without connected electrodes Phenomenon.

The phenomenon that the singular point of intensity s=+1 moves across the slit between electrode patterns occurs under the following conditions.

(1) When the interval between the slits between adjacent electrode patterns is very narrow;

(2) The shape of the electrode pattern itself is: when there are few parts restricting orientation such as fine slits, and the area of the electrode itself is large;

(3) When the display grayscale is relatively high (usually, the movement of the singular point does not occur at low grayscale).

In addition, as another problem, when the pixel electrode is brought into contact with the source of the TFT, the singular point with the intensity s=+1 that must be formed at the center of the pixel electrode flows toward the source due to the influence of the source electric field. Sometimes this results in a residual image.

In this embodiment, the following structure is adopted in order to eliminate residual images caused by vibration of the liquid crystal display device and color unevenness generated when the surface of the liquid crystal panel is pressed, and in order not to increase the number of manufacturing steps.

(1) In the pixel electrode of one pixel, the position of each electrode pattern in the cell is lower than the position of the peripheral edge of each electrode pattern. In this way, a structure is formed in which a wall surface made of an insulating layer is formed around the electrode pattern constituting the pixel electrode. In this case, since the insulating layer is formed in the portion where there are no electrodes, the same effect as that of forming a bank-like structure between adjacent electrode patterns can be obtained. Thus, it is possible to prevent the singular point with the intensity s=+1 from moving and combining across adjacent electrode patterns.

(2) In the pixel electrode of one pixel, the contact hole of the electrode pattern directly connected to the TFT is provided at the center of the electrode pattern, and the source of the TFT is extended to the contact hole of the electrode pattern. By disposing the contact hole at the center portion of the electrode pattern, the position where the singular point of intensity s=+1 due to the electrode pattern is generated coincides with the position where the singular point of intensity s=+1 is introduced on the part of the contact hole, so The singular points with intensity s=+1 must be generated at the same position. Thereby, since there is no shift in the generation position of the singular point with the intensity s=+1 on a pixel-by-pixel basis, no residual image is generated.

(3) The electrode unit adjacent to the electrode end portion of the gate bus line and in contact with the source of the TFT is made smaller than the electrode unit at other portions. By intentionally reducing the electrode units of the part where the singular point with intensity s=+1 is likely to collapse, the influence of abnormal singular points is actually reduced, and the proportion of crystal domains that are directionally divided can hardly be unbalanced. Therefore, from a macroscopic point of view, it can be considered that it is difficult to produce matte misorientation and residual images.

Next, the substrate for a liquid crystal display device according to this embodiment and the liquid crystal display device having the substrate will be specifically described using Examples 5-1 to 5-4.

(Example 5-1)

This embodiment will be described using FIG. 61 and FIG. 62 . FIG. 61 shows a pixel formed by a plurality of electrode units 26 . Fig. 62 shows a cross section taken along line D-D in Fig. 61 . The width of the pixel pitch extending in the direction of the drain bus line 14 (the long side direction of the pixel) is 300 μm, and the width of the pixel pitch extending in the direction of the gate bus line 12 is 100 μm.

On the glass substrate 52 of the TFT substrate 2, the drain bus lines 14 and the gate bus lines 12 having a width of 7 μm are formed. Between the drain bus line 14 and the gate bus line 12, a first insulating layer 500 mainly composed of SiO ₂ or the like is formed, and a second insulating layer 502 is further formed (see FIG. 62 ). The second insulating layer 502 is opened at a predetermined position. The positions of the openings are described below.

(1) The source electrode of the TFT 10 is opened. This is necessary for connection to the pixel electrode 16 . A square hole of about 5 μm is formed on the source electrode at the portion in contact with the electrode unit 26 .

(2) An opening having a size capable of accommodating the electrode unit 26 is formed at an arrangement position of the electrode unit 26 to be formed later. For example, the shape of the outer periphery of one electrode unit 26 is a square of 35 μm×35 μm, and in one pixel, two electrode units 26 are arranged horizontally and six electrode units 26 are arranged vertically. According to the positions of the electrode units 26 arranged in this way, holes with a size of 37 μm×37 μm are provided in the second insulating layer 502 .

Thereafter, an ITO layer as the pixel electrode 16 is formed on the entire surface by a method such as sputtering. Thereafter, the ITO layer is patterned by wet photolithography to form a plurality of electrode units 26 . The electrode unit 26 formed here is formed in the hole 504 of 37 μm×37 μm obtained by opening the second insulating layer 502 formed in the previous step. In addition, since each electrode unit 26 cannot be electrically independent, connection electrodes 36 having a width of approximately 4 μm are simultaneously formed at predetermined positions.

In addition, the drain of the TFT 10 for an adjacent pixel is arranged below the pixel in the figure. Therefore, in order to prevent the occurrence of alignment disorder or crosstalk caused by the drain, the end of the pixel electrode 16 is provided at a position 7 μm away from the drain so that the drain does not overlap the pixel electrode 16 .

Further, on the side of the CF substrate (counter substrate) 4 , a black matrix having a width of 23 μm is provided at a pitch of 300 μm×100 μm along the direction of the drain bus line 14 . In the openings, color filter (CF) layers of R, G, and B are respectively formed, and a common electrode made of ITO is closely formed on the upper surface in a "plate shape" over the entire surface. In addition, on the counter substrate 4, any bank-like structure for orientation regulation is not formed.

A vertical alignment film is formed on the two substrates, and the liquid crystal molecules are oriented in a direction perpendicular to the surface of the substrate (orientation film surface) in the state where no voltage is applied. The TFT substrate 2 and the counter substrate 4 are pasted with a predetermined cell gap, liquid crystal having negative dielectric anisotropy is injected, and then sealed.

Normally, when the liquid crystal panel configured in this way is driven, in one electrode unit 26 of the pixel electrode 16, directional division in approximately four directions from the ends (that is, the portion corresponding to the side) of the square toward the center can be realized.

As a comparative example, FIG. 63A and FIG. 63B show a pixel cross section of a conventional structure. FIG. 63A shows an alignment state of liquid crystal molecules 1 cm of liquid crystal sealed between the TFT substrate 2 and the CF substrate 4 . On the TFT substrate 2 , two adjacent electrode units 26 are formed through the slit 34 . In the voltage-applied state, as shown in the figure, the liquid crystal molecules are aligned at 1 cm, and the singular point with intensity s=+1 is arranged on the slit 34 . However, as shown in FIG. 63B, when the force F generated by finger pressure or the like acts on the liquid crystal panel, the liquid crystal molecules 1 cm are oriented in the same direction as shown in the figure, and the singular point with intensity s=+1 moves from the slit 34. or disappear. On the contrary, according to the present embodiment, the effect of the electric field caused by the edge of the pixel can be increased, and the orientation limiting force can be increased. In addition, as shown in FIG. 62, since the second insulating layer 502 of the slit 34 in the pixel electrode 16 functions as a bank-like alignment-regulating structure, the alignment regions between adjacent electrode units 26 are connected. Misorientation of appearance hardly occurs, and even if such a situation is supposed to occur, degradation of display quality can be prevented.

(Example 5-2)

This embodiment will be described using FIGS. 64 to 67C. 64 shows a sectional view cut at the same position as line D-D in FIG. 61 , and FIGS. 65A to 67C show cross-sectional views of the manufacturing process cut at the same position as line E-E in FIG. 61 . Since the shape of the electrode unit 26 is the same as that of Embodiment 5-1, its description is omitted. The difference between the present embodiment and the embodiment 5-1 is that an ITO layer as the pixel electrode 16 is initially formed. First, as shown in FIG. 65A , an ITO film 510 is formed on a glass substrate 52 . Next, the pattern of the ITO film 510 is formed by wet photolithography, and the pixel electrode 16 having the electrode unit 26 and the connection electrode 36 is formed as shown in FIG. 65B. Next, an insulating film 514 is formed on the entire surface (see 65C). Next, as shown in FIG. 65D , a gate material 516 is formed over the entire surface.

Next, after forming the pattern of the gate material 516, as shown in FIG. 66A, the gate bus line 12 is formed. Next, as shown in FIG. 66B , a gate insulating film 518 is formed, and a semiconductor layer (not shown) is formed and then patterned so that a channel layer (not shown) is formed on the upper layer of the gate bus line (gate) 12 . Next, as shown in FIG. 66C , a contact hole 520 is opened to expose the surface of the electrode unit 26 .

Next, as shown in FIG. 67A, the gate bus line forming metal layer 522 is formed and patterned to form the drain bus line 14, the drain 22, and the source 24, and the TFT 10 is produced (see 67B). Next, as shown in FIG. 67C , the gate insulating film 518 and the insulating film 514 in predetermined regions are photolithographically removed by dry photolithography, and the insulating layer 524 is formed on the connection electrode 36, so that the region where the pixel electrode 16 is formed is lower than other regions. TFT substrate 2 .

According to the structure of this embodiment, since the insulating layer 524 is formed only on the connection electrode 36 on the slit 34 and the connection electrode 36 electrically connected between each electrode unit 26 in the pixel electrode 16, it is possible to prevent the strength that occurred on the part of the connection electrode 36 before. The movement of the singular point of s=+1, therefore, a pixel structure that does not produce misorientation for finger pressure or vibration can be obtained. And the pixel structure can also be formed by using the same manufacturing process as the existing manufacturing process.

(Example 5-3)

This embodiment will be described using FIG. 68 . In this embodiment, the width of the pixel pitch (in the direction of the long side of the pixel) extending along the direction of the drain bus line 14 is 225 μm. On the other hand, the width of the pixel pitch extending in the direction of the gate bus line 12 is 75 μm. This is an example when the size of a pixel itself is small compared with Example 5-1.

Drain bus lines 14 and gate bus lines 12 having a width of 6 μm are formed on the TFT substrate 2 , and pixel electrodes 16 are formed of ITO at positions 7 μm away from them. That is, the width of the region where the pixel electrode 16 is formed is 55 μm. The pattern shape of the pixel electrode 16 will be described later. TFT 10 is formed near the intersection of drain bus line 14 and gate bus line 12 of each pixel.

The pixel electrode 16 is formed by arranging a total of three electrode units 26 in one row in the horizontal direction and three columns in the vertical direction. One electrode unit 26 is a square electrode having a peripheral shape of 55 μm×55 μm. The electrode units 26 are separated and adjacent to each other by a slit 34 having a width of 8 μm, and are electrically connected by a connection electrode 36 having a width of 4 μm. In the electrode unit 26 constituting the pixel electrode 16 , a contact hole 530 having a size of about 5 μm is provided approximately in the center of the electrode unit 26 directly connected to the TFT 10 . In the approximate center of the electrode unit 26 , in order to reliably form an electrode on the contact hole 530 , a plate-shaped close-contact electrode region is provided within a range of 5 μm around the contact hole 530 . In addition, the source electrode 24 is provided on the lower layer of the electrode unit 26 through an insulating layer, but must have a shape that does not protrude from the main portion 28 or the branch portion 30 of the electrode unit 26 as much as possible. This is to prevent the source electrode 24 from being formed under the gap 32 of the electrode unit 26 , causing the source electrode 24 and the electrode unit 26 to be at the same potential and unable to function as the gap 32 .

By doing this, when the pixel electrode 16 is made to contact the source 24 of the TFT 10, it is possible to avoid the flow of the singular point of intensity s=+1 that must be formed at the center of the electrode unit 26 to the source due to the influence of the electric field of the source 24. 24 direction phenomenon, so the display roughness caused by it can be reduced.

(Example 5-4)

This embodiment will be described using FIG. 69 . In this embodiment, the pixel pitch is the same as that in Embodiment 5-3.

The pixel electrode 16 is composed of a combination of a first electrode unit 26 and a second electrode unit 26'. The first electrode unit 26 is a square of 55 µm x 55 µm, and the second electrode unit 26' is a square of 24 µm x 24 µm. In the pixel electrode 16, the second electrode units 26' are arranged at the upper and lower ends of the pixel in two horizontal columns and one vertical column. The first electrode units 26 are arranged in one row in the horizontal direction and in two rows in the vertical direction at positions sandwiched by the second electrode units 26' at the upper and lower ends.

Thus, in this embodiment, the electrode end portion adjacent to the gate bus line 12 and the second electrode unit 26' in contact with the source 24 of the TFT 10 are smaller in size than the electrode unit 26 at other parts. By intentionally reducing the electrode unit 26' in the part where the singular point with the strength s=+1 is likely to collapse, the influence of abnormal singular points is actually reduced, so that the proportion of directional split crystal domains can hardly be unbalanced. For this reason, from a macroscopic point of view, it is possible to suppress the occurrence of poor alignment and residual images that are not smooth.

As described above, according to the present embodiment, the structure is such that the bank of the insulating layer is formed around the electrode pattern of the pixel electrode, and it is possible to suppress the variation of the singular point occurrence position without increasing the manufacturing process.

In addition, by setting the contact hole with the TFT as the center of the electrode pattern, the occurrence position of the singular point can be aligned, and the occurrence of afterimage can be suppressed.

The present invention is not limited to the above-described embodiments, and various modifications are possible.

For example, although a plurality of electrode units 26 of substantially the same shape are arranged in the pixel region in the above-mentioned embodiment, the present invention is not limited thereto, and a plurality of electrode units 26 of different shapes may be combined and arranged. As an example, there may be a configuration in which a plurality of electrode units 26 of two shapes symmetrical to each other with respect to the storage capacitor bus line 18 are arranged above and below the storage capacitor bus line 18 , respectively.

In addition, although the example of MVA-LCD was given in the above-mentioned embodiment, the present invention is not limited thereto, and can also be applied to other liquid crystal display devices such as TN (Twisted Nematic twisted nematic) mode.

In addition, in the above-mentioned embodiment, the example of the transmissive liquid crystal display device was cited, but the present invention is not limited thereto, and it can also be applied to a reflective or semi-transmissive type liquid crystal display device in which the pixel electrode 16 is formed with a light-reflective conductive film. and other liquid crystal display devices.

In addition, in the above-mentioned embodiment, an example of a liquid crystal display device in which CF is formed on the CF substrate 4 disposed opposite to the TFT substrate 2 is given, but the present invention is not limited thereto, and it can also be used to form CF on the TFT substrate 2, that is, A liquid crystal display device with a so-called CF-On-TFT structure.

As described above, according to the present invention, it is possible to obtain a substrate for a liquid crystal display device with good display quality and realize a liquid crystal display device having the substrate without increasing the number of manufacturing steps.

Claims (7)

1. a base plate for liquid crystal display device is characterized in that,

The insulativity substrate, it is with the counter substrate holding liquid crystal;

Many grid buss, it is formed on the described insulativity substrate and is substantially parallel mutually;

Many drain electrode buses, it intersects by dielectric film and described grid bus;

Pixel region, it is configured on the described insulativity substrate with rectangular;

Pixel electrode, it has: a plurality of electrode units that form in described pixel region; The slit that between described electrode unit, forms; The interconnective connection electrode of described a plurality of electrode units;

Thin film transistor (TFT), it is formed in each described pixel region,

The described electrode unit that adjoins each other only connects described connection electrode in a wherein end at the both ends on one side of described electrode unit periphery, and the bight of intersecting on the both sides of adjacency, and only on one side end connects described connection electrode therein.

2. base plate for liquid crystal display device as claimed in claim 1 is characterized in that,

Described connection electrode is connected to each limit of periphery of described electrode unit.

3. base plate for liquid crystal display device as claimed in claim 1 is characterized in that,

Described electrode unit has the interval of extending from the part on each limit of periphery,

Extend till near this limit to one side of adjacency at described interval.

4. base plate for liquid crystal display device as claimed in claim 3 is characterized in that,

Described interval is an axle with the central part of described electrode unit, with all have identical sense of rotation towards being arranged on each limit.

5. base plate for liquid crystal display device as claimed in claim 1 is characterized in that,

The width of described slit is more than the 5 μ m.

6. base plate for liquid crystal display device as claimed in claim 1 is characterized in that,

The length of described slit is below the 100 μ m.

7. base plate for liquid crystal display device as claimed in claim 1 is characterized in that,

The width of described connection electrode is below the 5 μ m.

Images