JP2013003286A - Liquid crystal device and electronic apparatus - Google Patents

Abstract

A liquid crystal device in which display unevenness due to uneven distribution due to diffusion of ionic impurities in a liquid crystal layer is reduced, and an electronic device including the liquid crystal device are provided.
A liquid crystal device according to this application example includes a liquid crystal layer 50 sandwiched between a pair of substrates, a plurality of pixel electrodes 15 provided on an element substrate 10 as one of the pair of substrates, and a pair. The counter substrate 20 as the other substrate is provided with a counter electrode 23 provided to face the plurality of pixel electrodes 15, and the pixel electrode 15 is provided with a convex portion 15b corresponding to the convex portion 15b. A convex portion 23 b is provided on the portion of the counter electrode 23. The flow of the liquid crystal molecules LC generated by driving the liquid crystal layer 50 is inhibited by the convex portions 15b and the convex portions 23b. Therefore, display unevenness caused by the ionic impurities in the liquid crystal layer 50 being diffused and unevenly distributed in a specific direction is reduced. A concave portion may be provided instead of the convex portion.
[Selection] Figure 8

Description

  The present invention relates to a liquid crystal device and an electronic apparatus including the same.

  A liquid crystal device generally has a structure in which liquid crystal is injected and sealed between a pair of substrates subjected to an alignment treatment. In the manufacturing process of such a liquid crystal device, it is known that, for example, when ionic impurities are mixed during liquid crystal injection or are eluted from a sealing material surrounding the liquid crystal layer, they are diffused and aggregated in the display region, resulting in deterioration of display characteristics. It has been.

  In order to suppress the deterioration of display characteristics due to such ionic impurities, for example, Patent Document 1 discloses that a shielding electrode is provided in a gap between a plurality of pixel electrodes arranged in a matrix on a drive circuit board. A liquid crystal display device is disclosed in which a potential is applied to the shielding electrode so as to have a predetermined potential difference from a plurality of pixel electrodes and a transparent electrode arranged with a liquid crystal layer interposed therebetween.

  According to the liquid crystal display device of Patent Document 1, ionic impurities in the liquid crystal layer can be captured (trapped) by the shielding electrode provided in the peripheral portion of the pixel electrode, so that display characteristics can be improved.

  For example, Patent Document 2 discloses a liquid crystal display device that includes a peripheral electrode including a plurality of electrodes on at least one side of a pixel electrode and a counter electrode, and a voltage value of a driving voltage is different between adjacent electrodes of the peripheral electrode. Is disclosed.

  According to the liquid crystal display device of Patent Document 2, a lateral electric field is generated by applying drive voltages having different voltage values to adjacent electrodes of peripheral electrodes. As a result, in addition to the flow caused by minute fluctuations of the liquid crystal, it becomes a force for moving the ionic impurities, and the ionic impurities moving from within the pixel region can be quickly moved out of the pixel region.

JP 2008-20725 A JP 2008-58497 A

However, according to Patent Documents 1 and 2 described above, a shield electrode and a peripheral electrode are provided, and a drive circuit for applying a potential to these electrodes is required, which causes a problem that the configuration of the liquid crystal display device becomes complicated. .
Moreover, providing a peripheral electrode like the said patent document 2 will lead to the enlargement of a liquid crystal display device. In other words, there was a problem that miniaturization was difficult.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A liquid crystal device according to this application example includes a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, a plurality of pixel electrodes on one of the pair of substrates, and the pair of substrates. A counter electrode opposite to the plurality of pixel electrodes is provided on the other substrate of the substrates, and at least one of the pixel electrode and the counter electrode has liquid crystal molecules generated by driving the liquid crystal molecules of the liquid crystal layer. A convex portion or a concave portion for inhibiting flow is formed.

  According to this configuration, since the flow of the liquid crystal molecules is inhibited by the convex portions or the concave portions, it is possible to reduce the diffusion and uneven distribution of ionic impurities in the liquid crystal layer due to the flow of the liquid crystal molecules. Therefore, it is possible to provide a liquid crystal device in which display unevenness due to uneven distribution of ionic impurities hardly occurs.

Application Example 2 In the liquid crystal device according to the application example described above, it is preferable that the convex portion or the concave portion is formed at least at a corner of the pixel electrode in the flow direction of the liquid crystal molecules.
According to this configuration, the flow of liquid crystal molecules generated by driving the liquid crystal layer can be efficiently inhibited on the pixel electrode side.

Application Example 3 In the liquid crystal device according to the application example described above, the convex portion or the concave portion may be formed in at least a portion of the counter electrode facing the corner of the liquid crystal molecule in the flow direction of the pixel electrode. .
According to this configuration, the flow of liquid crystal molecules caused by driving the liquid crystal layer can be efficiently inhibited on the counter electrode side.

Application Example 4 In the liquid crystal device according to the application example described above, the convex portion or the concave portion may be formed in a portion of the counter electrode facing between the pixel electrodes adjacent in the flow direction of the liquid crystal molecules. .
According to this configuration, the thickness of the liquid crystal layer between the pixel electrode and the counter electrode contributing to display does not vary even if the counter electrode is provided with a convex portion or a concave portion. In other words, it is possible to reliably avoid the deterioration of the optical characteristics due to the provision of the convex portion or the concave portion.

Application Example 5 In the liquid crystal device according to the application example described above, it is preferable that the convex portions or the concave portions are island-like and spaced apart from each other.
According to this configuration, since the convex portion or the concave portion is formed in an island shape, the flow of liquid crystal molecules inhibited by the convex portion or the concave portion is directed to the side where the convex portion or the concave portion is not formed. That is, it is possible to reduce the diffusion and uneven distribution of ionic impurities that move due to the flow of liquid crystal molecules in a specific direction.

Application Example 6 In the liquid crystal device according to the application example described above, the convex portion or the concave portion may be formed with a space between the pixel electrodes.
According to this structure, compared with the case where a convex part or a recessed part is provided for each pixel electrode, the flow of liquid crystal molecules can be inhibited with a simple structure without a complicated structure.

Application Example 7 In the liquid crystal device according to the application example described above, the convex portion or the concave portion may be formed on the pixel electrode located on the outer periphery of the effective display area or on the portion of the counter electrode facing the pixel electrode. Good.
According to this configuration, it is possible to reduce the occurrence of display unevenness due to uneven distribution of ionic impurities in the pixels located on the outer peripheral side of the effective display region by efficiently arranging the convex portions or the concave portions.

Application Example 8 In the liquid crystal device according to the application example, the liquid crystal device includes a transistor provided corresponding to the pixel electrode, and a light-shielding portion provided so as to overlap the transistor in a planar manner, and the convex portion or the concave portion. At least a part of is provided at a position overlapping the light shielding portion.
According to this configuration, the display unevenness caused by the difference in thickness of the liquid crystal layer in the portion provided with the convex portion or the concave portion from the other portion can be shielded by the light shielding portion and can be made inconspicuous.

Application Example 9 An electronic apparatus according to this application example includes the liquid crystal device according to the application example described above.
According to this configuration, display unevenness caused by diffusion and uneven distribution of ionic impurities in the liquid crystal layer is improved, and an electronic apparatus having excellent display quality can be provided.

(A) is a schematic plan view which shows the structure of a liquid crystal device, (b) is a schematic sectional drawing cut | disconnected by the H-H 'line | wire of (a). FIG. 3 is an equivalent circuit diagram illustrating an electrical configuration of the liquid crystal device. (A) is a schematic sectional drawing which shows the formation state of the inorganic alignment film in a liquid crystal device, and the orientation state of a liquid crystal molecule, (b) is the schematic which shows the behavior of a liquid crystal molecule. The schematic plan view which shows an example of the display nonuniformity accompanying the uneven distribution of an ionic impurity. FIG. 3 is a schematic plan view illustrating the arrangement of pixels in the liquid crystal device according to the first embodiment. FIG. 3 is a schematic plan view showing the arrangement of convex portions or concave portions in the liquid crystal device of Example 1. (A) is schematic sectional drawing which shows the structure of the convex part of Example 1 cut | disconnected by the AA 'line of FIG. 6, (b) is the recessed part of Example 1 cut | disconnected by the AA' line of FIG. The schematic sectional drawing which shows a structure. FIG. 3 is a schematic cross-sectional view showing a state of liquid crystal molecules during driving in the liquid crystal device of Example 1. FIG. 6 is a schematic plan view showing the arrangement of convex portions or concave portions in the liquid crystal device of Example 2. FIG. 6 is a schematic plan view showing the arrangement of convex portions or concave portions in the liquid crystal device of Example 3. Schematic which shows the structure of the projection type display apparatus as an electronic device. (A) And (b) is a schematic plan view which shows arrangement | positioning of the convex part or recessed part of a modification. (A) is a schematic plan view which shows arrangement | positioning of the convex part or recessed part in the counter electrode of a modification, (b) And (c) is a schematic sectional drawing cut | disconnected by the D-D 'line | wire of (a).

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. Note that the drawings to be used are appropriately enlarged or reduced so that the part to be described can be recognized.

  In the following embodiments, for example, when “on the substrate” is described, the substrate is disposed so as to be in contact with the substrate, or is disposed on the substrate via another component, or the substrate. It is assumed that a part is arranged so as to be in contact with each other and a part is arranged via another component.

(First embodiment)
<Liquid crystal device>
First, the liquid crystal device of this embodiment will be described with reference to FIGS. 1A is a schematic plan view showing the configuration of the liquid crystal device, FIG. 1B is a schematic cross-sectional view taken along line HH ′ of FIG. 1A, and FIG. 2 is an electrical configuration of the liquid crystal device. FIG.

  As shown in FIGS. 1A and 1B, a liquid crystal device 100 according to the present embodiment includes an element substrate 10 and a counter substrate 20 that are disposed to face each other, and a liquid crystal layer 50 that is sandwiched between the pair of substrates. . The element substrate 10 and the counter substrate 20 are made of a transparent substrate such as a quartz substrate or a glass substrate.

  Of the pair of substrates, the element substrate 10 as one substrate is slightly larger than the counter substrate 20 as the other substrate, and both the substrates are joined via a sealing material 40 arranged in a frame shape, and the gap is formed in the gap. Liquid crystal having a negative dielectric anisotropy is sealed to constitute the liquid crystal layer 50. For the sealing material 40, for example, an adhesive such as a thermosetting or ultraviolet curable epoxy resin is employed. A spacer (not shown) is mixed in the sealing material 40 to keep the distance between the pair of substrates constant.

  A light shielding film 21 is similarly provided in a frame shape inside the sealing material 40 arranged in a frame shape. The light shielding film 21 is made of, for example, a light shielding metal or metal oxide, and the inside of the light shielding film 21 is a display region E. In the display area E, a plurality of pixels P are arranged in a matrix. Although not shown in FIG. 1, the display area E is also provided with a light-shielding portion that divides a plurality of pixels P in a plane.

A data line driving circuit 101 is provided between the element substrate 10 and the sealing material 40 along one side. Further, an inspection circuit 103 is provided inside the sealing material 40 along the other one side facing the one side. Further, a scanning line driving circuit 102 is provided inside the sealing material 40 along the other two sides orthogonal to the one side and facing each other. A plurality of wirings 105 that connect the two scanning line driving circuits 102 are provided inside the sealing material 40 on the other side facing the one side. Wirings connected to the data line driving circuit 101 and the scanning line driving circuit 102 are connected to a plurality of external connection terminals 104 arranged along the one side.
Hereinafter, the direction along the one side will be referred to as the X direction, and the direction along the other two sides orthogonal to the one side and facing each other will be described as the Y direction.

As shown in FIG. 1B, on the surface of the element substrate 10 on the liquid crystal layer 50 side, a light-transmitting pixel electrode 15 provided for each pixel P and a thin film transistor (TFT; Thin Film) as a switching element. Transistor) 30, signal wiring, and an alignment film 18 covering these are formed.
Further, a light shielding structure is employed that prevents light from entering the semiconductor layer in the TFT 30 and causing a light leakage current to flow, resulting in an inappropriate switching operation.

  On the surface of the counter substrate 20 on the liquid crystal layer 50 side, a light shielding film 21, an interlayer insulating film 22 formed so as to cover the light shielding film 21, and an interlayer insulating film 22 covering at least the display region E are provided. The counter electrode 23 and an alignment film 24 covering the counter electrode 23 are provided.

  As shown in FIG. 1A, the light shielding film 21 is provided in a frame shape at a position where the data line driving circuit 101, the scanning line driving circuit 102, and the inspection circuit 103 overlap in plan view. Thus, the light incident from the counter substrate 20 side is shielded, and the malfunction of the peripheral circuits including these drive circuits due to the light is prevented. Further, unnecessary stray light is shielded from entering the display area E, and high contrast in the display of the display area E is ensured.

  The interlayer insulating film 22 is made of an inorganic material such as silicon oxide, for example, and is provided so as to cover the light shielding film 21 with light transmittance. As a method for forming the interlayer insulating film 22, for example, a method of forming a film using a plasma CVD method or the like can be given.

  The counter electrode 23 is made of, for example, a transparent conductive film such as ITO, and covers the interlayer insulating film 22 and, as shown in FIG. 1A, the element substrate 10 side by the vertical conduction portions 106 provided at the four corners of the counter substrate 20. It is electrically connected to the wiring.

  The alignment film 18 that covers the pixel electrode 15 and the alignment film 24 that covers the counter electrode 23 are selected based on the optical design of the liquid crystal device 100. In this embodiment, liquid crystal molecules having negative dielectric anisotropy are applied so as to be vertically aligned with a pretilt with respect to the alignment film surface. For example, an inorganic material such as SiOx (silicon oxide) is used. An inorganic alignment film in which a material is formed by physical vapor deposition is used. Examples of the physical vapor deposition method include a vacuum vapor deposition method and a vacuum sputtering method in which an inorganic material is vaporized in a vacuum and reaches a film-forming object to form a film. The method for forming the inorganic alignment film and the detailed alignment state of the liquid crystal molecules will be described later.

  As shown in FIG. 2, the liquid crystal device 100 has a plurality of scanning lines 3a and a plurality of data lines 6a as signal lines that are insulated and orthogonal to each other at least in the display region E, and a certain distance from the scanning line 3a. And a capacitance line 3b arranged parallel to each other.

  A pixel electrode 15, a TFT 30, and a storage capacitor 16 are provided in a region divided by the scanning line 3a, the data line 6a, the capacitor line 3b, and these signal lines, and these constitute a pixel circuit of the pixel P. doing.

The scanning line 3 a is electrically connected to the gate of the TFT 30, and the data line 6 a is electrically connected to the source of the TFT 30. The pixel electrode 15 is electrically connected to the drain of the TFT 30.
The data line 6a is connected to the data line driving circuit 101 (see FIG. 1), and supplies image signals D1, D2,..., Dn supplied from the data line driving circuit 101 to the pixels P. The scanning line 3a is connected to a scanning line driving circuit 102 (see FIG. 1), and supplies scanning signals SC1, SC2,..., SCm supplied from the scanning line driving circuit 102 to each pixel P. The image signals D1 to Dn supplied from the data line driving circuit 101 to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each of a plurality of adjacent data lines 6a for each group. Good. The scanning line driving circuit 102 supplies the scanning signals SC1 to SCm to the scanning line 3a in a pulse-sequential manner at a predetermined timing.

In the liquid crystal device 100, the TFT 30 that is a switching element is turned on for a certain period by the input of the scanning signals SC1 to SCm, so that the image signals D1 to Dn supplied from the data line 6a are supplied to the pixel electrode 15 at a predetermined timing. It is the structure written in. The predetermined level of image signals D1 to Dn written to the liquid crystal layer 50 through the pixel electrode 15 are held for a certain period between the pixel electrode 15 and the counter electrode 23 arranged to face each other through the liquid crystal layer 50. The
In order to prevent the held image signals D1 to Dn from leaking, the holding capacitor 16 is connected in parallel with the liquid crystal capacitor formed between the pixel electrode 15 and the counter electrode 23. The storage capacitor 16 is provided between the drain of the TFT 30 and the capacitor line 3b.

  Note that a data line 6a is connected to the inspection circuit 103 shown in FIG. 1A, and an operation defect or the like of the liquid crystal device 100 is confirmed by detecting the image signal in the manufacturing process of the liquid crystal device 100. Although it can be configured, it is omitted in the equivalent circuit of FIG. The inspection circuit 103 includes a sampling circuit that samples the image signal and supplies it to the data line 6a, and a precharge circuit that supplies a precharge signal of a predetermined voltage level to the data line 6a prior to the image signal. Also good.

  Such a liquid crystal device 100 is a transmission type, and adopts an optical design of a normally black mode in which a dark display is obtained when the pixel P is not driven and a normally white mode in which a bright display is obtained when the pixel P is not driven. Depending on the optical design, polarizing elements are respectively used on the light incident side and the light exit side.

  Next, the alignment state of the liquid crystal molecules in the liquid crystal device 100 will be described with reference to FIG. FIG. 3A is a schematic sectional view showing the formation state of the inorganic alignment film and the alignment state of the liquid crystal molecules in the liquid crystal device, and FIG. 3B is a schematic view showing the behavior of the liquid crystal molecules.

  As shown in FIG. 3A, the orientation obtained by obliquely depositing silicon oxide on the surfaces of the pixel electrode 15 and the counter electrode 23 in the liquid crystal device 100 by vacuum vapor deposition which is an example of physical vapor deposition. A film 18 and an alignment film 24 are formed. Specifically, the angle θb of the vapor deposition direction with respect to the substrate surface facing the liquid crystal layer 50 is approximately 45 °. By such oblique vapor deposition, silicon oxide crystals grow in a columnar shape on the substrate surface in the vapor deposition direction. These columnar crystals are called columns 18a and 24a. The alignment films 18 and 24 are aggregates of such columns 18a and 24a. Further, the angle θc in the growth direction of the columns 18a and 24a with respect to the substrate surface does not necessarily coincide with the angle θb in the vapor deposition direction, and in this case, is approximately 70 °.

The pretilt angle θp of the liquid crystal molecules LC vertically aligned on the surfaces of the alignment films 18 and 24 is about 85 °. In addition, the pretilt direction, that is, the tilt direction for tilting the liquid crystal molecules LC viewed from the normal direction of the substrate surface is the same as the planar deposition direction of the oblique deposition in the alignment films 18 and 24. The tilt direction of the vertical alignment process is appropriately set based on the optical design conditions of the liquid crystal device 100.
The alignment state in which the liquid crystal molecules LC having negative dielectric anisotropy with respect to the alignment film surface are inverted by being given a pretilt angle θp of less than 90 ° is referred to as substantially vertical alignment.

  A device including the element substrate 10 and the counter substrate 20 arranged to face each other and the liquid crystal layer 50 sandwiched between the pair of substrates is referred to as a liquid crystal panel 110. The liquid crystal device 100 is used with polarizing elements 41 and 42 disposed on the light incident side and the light exit side of the liquid crystal panel 110, respectively. Further, the polarizing elements 41 and 42 are such that one transmission axis or absorption axis of the polarizing elements 41 and 42 is parallel to the X direction or the Y direction, and the transmission axes or absorption axes thereof are orthogonal to each other. In this manner, the liquid crystal panel 110 is disposed.

In the present embodiment, a substantially vertical alignment process is performed in the display region E so that the azimuth angle of the pretilt of the liquid crystal molecules LC intersects with the transmission axes or absorption axes of the polarizing elements 41 and 42 at 45 °. Therefore, as shown in FIG. 3B, when a driving voltage is applied between the pixel electrode 15 and the counter electrode 23 to drive the liquid crystal layer 50, the liquid crystal molecules LC are tilted in the pretilt tilt direction, resulting in high transmission. It is an optical arrangement that provides a good rate.
When driving (ON / OFF) of the liquid crystal layer 50 is repeated, the liquid crystal molecules LC repeatedly behave in such a manner as to fall in the tilt direction of the pretilt or return to the initial alignment state. Such a substantially vertical alignment treatment in which the behavior of the liquid crystal molecules LC occurs is referred to as a uniaxial substantially vertical alignment treatment.

  In addition, the incident direction of the light with respect to the liquid crystal panel 110 is not limited to entering from the element substrate 10 side, as shown to Fig.3 (a). In addition, an optical compensation element such as a phase difference plate may be provided on the light incident side or the light emitting side.

  Next, display unevenness caused by uneven distribution of ionic impurities to be solved by the present invention will be described with reference to FIG. FIG. 4 is a schematic plan view showing an example of display unevenness due to uneven distribution of ionic impurities. FIG. 4 shows a case where the optical design of the liquid crystal device is normally black.

  As shown in FIG. 4, the tilt direction of the pretilt of the liquid crystal molecules LC in the display region E is set so that the azimuth angle θa made with the Y direction is 45 °. Specifically, an arrow direction indicated by a broken line is a direction of oblique deposition with respect to the element substrate 10 and is a direction from the upper right to the lower left. On the other hand, the arrow direction indicated by the solid line is the direction of oblique vapor deposition with respect to the counter substrate 20 disposed to face the element substrate 10, and is the direction from the lower left to the upper right (see FIG. 3). Such a tilt direction of the pretilt of the liquid crystal molecules LC in the display region E is referred to as a tilt direction θa using the azimuth angle θa as it is.

According to such a tilt direction θa, when the pixel P is driven, the liquid crystal molecules LC aligned substantially perpendicular to the substrate surface are swung in the tilt direction θa (see FIG. 3B). As a result, the behavior of the liquid crystal molecules LC toward the tilt direction θa, that is, the flow (flow) occurs, and the ionic impurities contained in the liquid crystal move in the liquid crystal along the flow (flow). The ionic impurities are unevenly distributed by being conveyed to the corners located in the inclination direction θa. Then, as shown in FIG. 4, display unevenness such as burn-in and luminance unevenness due to uneven distribution of ionic impurities occurs at the corners of the display region E. More specifically, for example, in the case of normally black, light leakage occurs in the pixel P located at the corner, and the contrast is lowered. FIG. 4 shows a state in which light leakage has occurred in the three pixels P located at the corners of the display area E.
Note that the inclination direction θa of 45 ° is not limited to 45 ° to the right as shown in FIG. 4 but may be 45 ° to the right. In this case, the upper left and lower right corners of the display area E in FIG. Display unevenness. That is, the tilt direction θa of the liquid crystal molecules LC when a driving voltage is applied to the liquid crystal layer 50 is the flow direction of the liquid crystal molecules LC.

  The inventor has developed the liquid crystal device 100 in order to improve display unevenness at the corners of the display region E due to uneven distribution of ionic impurities. Specifically, convex portions or concave portions that inhibit the flow of the liquid crystal molecules LC are provided on the surface of the pixel electrode 15 and / or the counter electrode 23 to suppress uneven distribution of ionic impurities in the liquid crystal layer 50. Hereinafter, an example is given and demonstrated.

Example 1
FIG. 5 is a schematic plan view showing the arrangement of pixels in the liquid crystal device of the first embodiment, FIG. 6 is a schematic plan view showing the arrangement of convex portions or concave portions in the liquid crystal device of the first embodiment, and FIG. The schematic sectional drawing which shows the structure of the convex part of Example 1 cut | disconnected by the AA 'line, The figure (b) is a schematic cross section which shows the structure of the recessed part of Example 1 cut | disconnected by the AA' line of FIG. 8 and 8 are schematic cross-sectional views showing the state of liquid crystal molecules during driving in the liquid crystal device of Example 1. FIG. In FIGS. 7 and 8, the alignment films 18 and 24 are not shown.

  As shown in FIG. 5, the pixel P in the liquid crystal device 100 has, for example, a substantially rectangular opening area in a plan view. The opening region is surrounded by a light-shielding non-opening region (light-shielding portion) that extends in the X direction and the Y direction and is provided in a lattice shape.

  In the non-opening region (light shielding portion) extending in the X direction, the scanning line 3a and the capacitance line 3b shown in FIG. 2 are provided. The scanning lines 3a and the capacitor lines 3b use light-shielding conductive members, and at least a part of the non-opening region (light-shielding part) is configured by the scanning lines 3a and the capacitor lines 3b.

  Similarly, the data line 6a shown in FIG. 2 is provided in the non-opening region (light shielding portion) extending in the Y direction. The data line 6a also uses a light-shielding conductive member, and at least a part of the non-opening region (light-shielding portion) is configured by these.

  The non-opening region (light-shielding part) can be constituted not only by the signal lines provided on the element substrate 10 side, but also by a light-shielding part patterned in a lattice pattern on the counter substrate 20 side.

  The TFT 30 and the storage capacitor 16 shown in FIG. 2 are provided near the intersection of the non-opening region (light-shielding portion). By providing the TFT 30 in the vicinity of the intersection of the non-opening region (light-shielding portion) having a light-shielding property, an optical malfunction of the TFT 30 is prevented and an aperture ratio in the opening region is ensured. In view of providing the TFT 30 and the storage capacitor 16 near the intersection, the width of the non-opening region (light-shielding portion) near the intersection is wider than the other portions.

  As shown in FIG. 6, the convex portions or concave portions in the first embodiment are opposed to the four corner portions 15d, 15e, 15f, and 15g of the pixel electrode 15 in the pixel P and the corner portions 15d, 15e, 15f, and 15g. The counter electrode 23 is provided in a portion (region) 23d. Further, these corners 15d, 15e, 15f, 15g and the portion (area) 23d of the counter electrode 23 are located at the intersections of the aforementioned non-opening areas (light-shielding portions) in the plurality of pixels P arranged in a matrix. At least a portion overlaps in a plane. In FIG. 6, the corners 15d, 15e, 15f, and 15g are hatched so as to be easily distinguished. A portion (region) 23d of the counter electrode 23 is a region surrounded by a broken line.

  The AA ′ line in FIG. 6 represents the corners 15d and 15f and the portion (region) 23d of the counter electrode 23 located at the diagonals of the adjacent pixels P along the inclination direction of the liquid crystal molecules LC, that is, the flow direction. Crossing. The corners 15d, 15e, 15f, 15g are right-angled isosceles triangles in plan view, and the hypotenuses are orthogonal to the flow direction of the liquid crystal molecules LC. Similarly, the portion (region) 23d of the counter electrode 23 is a quadrangle (square) in plan view, and one of the opposing sides is orthogonal to the flow direction of the liquid crystal molecules LC.

  More specifically, as shown in FIG. 7A, convex portions 15b are provided at positions corresponding to the corner portions 15d and 15f of the pixel electrode 15. In addition, a convex portion 23 b is provided at a position corresponding to the portion (region) 23 d of the counter electrode 23.

  The convex portion 15 b is formed by patterning the pixel electrode 15 so as to protrude from the reference surface 15 a of the pixel electrode 15 toward the liquid crystal layer 50. For example, after the pixel electrode 15 having a certain thickness is formed, the pixel electrode 15 is etched leaving the convex portion 15b, thereby forming the reference surface 15a and the convex portion 15b of the pixel electrode 15. It is done.

  Similarly, the convex portion 23 b is formed by patterning the counter electrode 23 so as to protrude from the reference surface 23 a of the counter electrode 23 toward the liquid crystal layer 50. For example, after the counter electrode 23 having a certain thickness is formed, the reference electrode 23a and the convex portion 23b of the counter electrode 23 are formed by etching the counter electrode 23 while leaving the portion of the convex portion 23b. It is done.

It is desirable that the heights of the protrusions 15b and 23b protruding from the respective reference surfaces 15a and 23a are at least 150 nm. Further, the convex portion 15 b of the pixel electrode 15 and the convex portion 23 b of the counter electrode 23 are opposed to each other through the liquid crystal layer 50. When the thickness of the liquid crystal layer 50 between the reference surface 15 a of the pixel electrode 15 and the reference surface 23 a of the counter electrode 23 is d ₀ , the liquid crystal between the convex portion 15 b of the pixel electrode 15 and the convex portion 23 b of the counter electrode 23. The thickness d _{1 of the} layer 50 desirably satisfies the relationship d ₁ ≧ 3/4 × d ₀ .

  Further, as shown in FIG. 7B, the recesses 15c may be provided in the corners 15d and 15f of the pixel electrode 15, and the recesses 23c may be provided in the part (region) 23d of the counter electrode 23.

  The recess 15 c is formed by patterning the pixel electrode 15 so as to be recessed from the reference surface 15 a of the pixel electrode 15. For example, after the pixel electrode 15 having a certain thickness is formed, the reference surface 15a and the recess 15c are formed by etching the pixel electrode 15 while leaving a portion of the reference surface 15a.

  Similarly, the concave portion 23 c is formed by patterning the counter electrode 23 so as to be recessed from the reference surface 23 a of the counter electrode 23. For example, after the counter electrode 23 having a certain thickness is formed, the reference surface 23a and the recess 23c are formed by etching the counter electrode 23 while leaving a portion of the reference surface 23a.

The depths of the recesses 15c and 23c that are recessed from the respective reference surfaces 15a and 23a are preferably at least 150 nm. Further, the recess 15 c of the pixel electrode 15 and the recess 23 c of the counter electrode 23 face each other with the liquid crystal layer 50 interposed therebetween. When the thickness of the liquid crystal layer 50 between the reference surface 15 a of the pixel electrode 15 and the reference surface 23 a of the counter electrode 23 is d ₀ , the liquid crystal layer 50 between the recess 15 c of the pixel electrode 15 and the recess 23 c of the counter electrode 23. It is desirable that the thickness d ₂ satisfies the relationship d ₂ ≦ 5/4 × d ₀ .

  As shown in FIG. 8, for example, when the pixel electrode 15 is provided with the convex portion 15 b and the counter electrode 23 is provided with the convex portion 23 b, a liquid crystal is applied by applying a driving voltage between the pixel electrode 15 and the counter electrode 23. When the layer 50 is driven, the liquid crystal molecules LC change from the substantially vertically aligned state to the inclined state. By repeating such behavior of the liquid crystal molecules LC, the liquid crystal molecules LC flow along the reference surface 15a of the pixel electrode 15 and the reference surface 23a of the counter electrode 23. However, the flow of the liquid crystal molecules LC is hindered by colliding with the projections 15 b of the pixel electrode 15 and the projections 23 b of the counter electrode 23.

  In FIG. 8, the example in which the pixel electrode 15 is provided with the convex portion 15b and the counter electrode 23 is provided with the convex portion 23b has been described. However, as shown in FIG. The same effect can be obtained even when the recess 23c is provided in the electrode 23. That is, the flow of the liquid crystal molecules LC generated along the reference surface 15 a of the pixel electrode 15 and the reference surface 23 a of the counter electrode 23 does not flow smoothly by the recess 15 c of the pixel electrode 15 or the recess 23 c of the counter electrode 23. It is blocked by.

  Accordingly, the flow of the liquid crystal molecules LC prevents the ionic impurities in the liquid crystal layer 50 from being carried in the tilt direction (flow direction) of the liquid crystal molecules LC.

  From the viewpoint of inhibiting the flow of the liquid crystal molecules LC, the convex portions 15b and concave portions 15c of the pixel electrode 15 and the convex portions 23b and concave portions 23c of the counter electrode 23 are provided at portions corresponding to the corner portions 15d and 15f. It only has to be. In the first embodiment, in consideration of the influence of the structure of the pixel P on the optical characteristics (viewing angle characteristics and the like), the convex portions or the concave portions are provided in the portions corresponding to the corner portions 15e and 15g, and the pixel P The symmetry of the structure is secured.

(Example 2)
FIG. 9 is a schematic plan view illustrating the arrangement of convex portions or concave portions in the liquid crystal device according to the second embodiment. The convex portions or concave portions of the second embodiment are different from the first embodiment in the arrangement shapes of the corner portions 15d, 15e, 15f, and 15g of the pixel electrode 15 and the portion 23d of the counter electrode 23 that faces the corner portions 15d, 15e, 15f, and 15g. . 9, corners 15d, 15e, 15f, and 15g are hatched, and a portion (area) 23d of the counter electrode 23 is surrounded by a broken line.

  Specifically, as shown in FIG. 9, the corners 15d, 15e, 15f, and 15g of the pixel electrode 15 are quadrangular (square) in plan view. By adopting such an arrangement shape, the corners 15d, 15e, 15f, 15g and the portion 23d of the counter electrode 23 facing the corners 15d, 15e, 15f, 15g are formed at the intersections of the non-opening regions in the pixels P arranged in the matrix form described above. Can be paid. That is, the convex portions or concave portions provided in the corner portions 15d, 15e, 15f, 15g and the portion 23d of the counter electrode 23 are shielded by the light shielding portion.

  The BB ′ line in FIG. 9 is drawn in the same direction as the AA ′ line in FIG. 6, and its cross-sectional structure is the same as the structure shown in FIGS. 7 (a) and (b). The flow of the liquid crystal molecules LC generated by driving the liquid crystal layer 50 is hindered by the convex portions or concave portions provided in the pixel electrode 15 and the counter electrode 23.

(Example 3)
FIG. 10 is a schematic plan view illustrating the arrangement of convex portions or concave portions in the liquid crystal device according to the third embodiment. The convex portions or concave portions of the third embodiment are different from the first embodiment in the arrangement shapes of the corner portions 15d, 15e, 15f, and 15g of the pixel electrode 15 and the portion 23d of the counter electrode 23 facing the corner portions 15d, 15e, 15f, and 15g. . In FIG. 10, corners 15d, 15e, 15f, and 15g are hatched, and a portion (region) 23d of the counter electrode 23 is surrounded by a broken line.

  Specifically, as shown in FIG. 10, the corners 15d, 15e, 15f, and 15g of the pixel electrode 15 have a shape (L-shape) in which a quadrangle is bent at a right angle in plan view. By adopting such an arrangement shape, the corners 15d, 15e, 15f, 15g and the portion 23d of the counter electrode 23 facing the corners 15d, 15e, 15f, 15g are formed at the intersections of the non-opening regions in the pixels P arranged in the matrix form described above. Be paid.

  The CC ′ line in FIG. 10 is drawn in the same direction as the AA ′ line in FIG. 6, and its cross-sectional structure is the same as the structure shown in FIGS. 7A and 7B. The flow of the liquid crystal molecules LC generated by driving the liquid crystal layer 50 is hindered by the convex portions or concave portions provided in the pixel electrode 15 and the counter electrode 23. In particular, in the third embodiment, since the planar shapes of the corner portions 15d and 15f of the pixel electrode 15 and the portion 23d of the counter electrode 23 facing the pixel portions 15 are bent, the liquid crystal molecules LC are compared with the first and second embodiments. The effect which inhibits the flow of is obtained more.

  In the first to third embodiments described above, the pixel electrode 15 and the counter electrode 23 are each provided with a convex portion or a concave portion. Effect is obtained. In addition, a combination in which one of the pixel electrode 15 and the counter electrode 23 is provided with a convex portion and the other is provided with a concave portion can be employed.

According to the embodiment described above, the following effects can be obtained.
(1) The liquid crystal device 100 includes the corner portions 15d and 15f of the pixel electrode 15 in the flow direction of the liquid crystal molecules LC and the counter electrode 23 facing the corner portions 15d and 15f as shown in the first to third embodiments. A convex portion or a concave portion is provided in the portion (area) 23d. Therefore, the flow of the liquid crystal molecules LC is hindered by the convex portions or the concave portions, and ionic impurities in the liquid crystal layer 50 are moved by the flow of the liquid crystal molecules LC and are reduced from being unevenly distributed at the corners of the display region E. it can. Therefore, it is possible to provide the liquid crystal device 100 in which display unevenness due to uneven distribution of ionic impurities is reduced.
(2) As shown in the first to third embodiments, the convex portions 15b and 23b or the concave portions 15c and 23c provided on the pixel electrode 15 and the counter electrode 23 are provided in an island shape in isolation from each other. The movement of the ionic impurities in the layer 50 in a specific direction can be reduced, and the ionic impurities can be diffused in the direction in which the convex portions 15b and 23b and the concave portions 15c and 23c are not provided. In other words, a higher effect can be expected compared to the case where convex portions and concave portions are provided so as to surround the outer periphery of the pixel electrode 15 in that it is difficult to make ionic impurities unevenly distributed in a specific portion.
(3) As shown in Example 1, the protrusions 15b and 23b or the recesses 15c and 23c provided on the pixel electrode 15 and the counter electrode 23 have a height and depth with respect to the reference surfaces 15a and 23a of at least 150 nm or more. ing. In addition, since the thickness of the liquid crystal layer 50 in the portions where the convex portions 15b and 23b or the concave portions 15c and 23c are provided is within ± 25% of the reference thickness d ₀ , the influence on the optical characteristics of the pixel P is reduced. While suppressing the flow of the liquid crystal molecules LC, the uneven distribution of ionic impurities can be reliably reduced.
(4) As shown in the first embodiment, the convex portions 15b and 23b or the concave portions 15c and 23c provided on the pixel electrode 15 and the counter electrode 23 are at least crossed with the intersection in the non-opening region of the pixel P arranged in a matrix. It is arranged so that a part overlaps. Therefore, even if a problem such as light leakage due to the provision of the convex portions 15b and 23b or the concave portions 15c and 23c occurs, the problem can be made inconspicuous. In the second embodiment and the third embodiment, the defect can be almost completely covered.

(Second Embodiment)
<Electronic equipment>
Next, the electronic apparatus of this embodiment will be described with reference to FIG. FIG. 11 is a schematic diagram illustrating a configuration of a projection display device as an electronic apparatus.

  As shown in FIG. 11, a projection display apparatus 1000 as an electronic apparatus according to the present embodiment includes a polarized illumination apparatus 1100 arranged along the system optical axis L, and two dichroic mirrors 1104 and 1105 as light separation elements. Three reflection mirrors 1106, 1107, 1108, five relay lenses 1201, 1202, 1203, 1204, 1205, three transmissive liquid crystal light valves 1210, 1220, 1230 as light modulation means, and a light combining element As a cross dichroic prism 1206 and a projection lens 1207.

  The polarized light illumination device 1100 is generally configured by a lamp unit 1101 as a light source composed of a white light source such as an ultra-high pressure mercury lamp or a halogen lamp, an integrator lens 1102, and a polarization conversion element 1103.

  The dichroic mirror 1104 reflects red light (R) and transmits green light (G) and blue light (B) among the polarized light beams emitted from the polarization illumination device 1100. Another dichroic mirror 1105 reflects the green light (G) transmitted through the dichroic mirror 1104 and transmits the blue light (B).

The red light (R) reflected by the dichroic mirror 1104 is reflected by the reflection mirror 1106 and then enters the liquid crystal light valve 1210 via the relay lens 1205.
Green light (G) reflected by the dichroic mirror 1105 enters the liquid crystal light valve 1220 via the relay lens 1204.
The blue light (B) transmitted through the dichroic mirror 1105 enters the liquid crystal light valve 1230 via a light guide system including three relay lenses 1201, 1202, 1203 and two reflection mirrors 1107, 1108.

  The liquid crystal light valves 1210, 1220, and 1230 are disposed to face the incident surfaces of the cross dichroic prism 1206 for each color light. The color light incident on the liquid crystal light valves 1210, 1220, and 1230 is modulated based on video information (video signal) and emitted toward the cross dichroic prism 1206. In this prism, four right-angle prisms are bonded together, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface thereof. The three color lights are synthesized by these dielectric multilayer films, and the light representing the color image is synthesized. The synthesized light is projected on the screen 1300 by the projection lens 1207 which is a projection optical system, and the image is enlarged and displayed.

  The liquid crystal light valve 1210 is the one to which the liquid crystal device 100 described above is applied. The liquid crystal device 100 is arranged with a gap between a pair of polarizing elements arranged in crossed Nicols on the incident side and the emission side of colored light. The same applies to the other liquid crystal light valves 1220 and 1230.

  According to such a projection display device 1000, the liquid crystal device 100 in which uneven distribution of ionic impurities in the liquid crystal layer 50 is suppressed, display unevenness due to energization is reduced, and high display quality and reliability are realized. ing.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. Electronic equipment to which the liquid crystal device 100 is applied is also included in the technical scope of the present invention. Various modifications other than the above embodiment are conceivable. Hereinafter, a modification will be described.

(Modification 1) In the liquid crystal device 100, the present invention is not limited to the provision of a convex portion or a concave portion for each pixel P. FIGS. 12A and 12B are schematic plan views showing the arrangement of convex portions or concave portions according to the modification. For example, as shown in FIG. 12A, corners 15d, 15e, 15f, 15g of a pixel electrode 15 provided with a convex portion or a concave portion and a portion 23d of the counter electrode 23 facing the corner portions 15d, 15e, 15f, 15g. You may arrange | position at intervals. According to this, it is possible to inhibit the flow of the liquid crystal molecules LC while suppressing the influence on the optical characteristics of the pixel P, that is, the display area E, by providing the convex portion or the concave portion.
Further, as shown in FIG. 12B, the corners 15d, 15e, 15f, 15g of the pixel electrode 15 located on the outer periphery of the effective display area E, or facing the corners 15d, 15e, 15f, 15g. A convex portion or a concave portion may be formed on the portion 23 d of the electrode 23. According to this, it is possible to efficiently arrange the convex portions or the concave portions and reduce the occurrence of display unevenness due to uneven distribution of ionic impurities in the pixels P located on the outer peripheral side of the effective display region E. As described above, the convex portions or the concave portions corresponding to the four corner portions 15d, 15e, 15f, and 15g are not provided, but the convex portions corresponding to the corner portions 15d and 15f located in the flow direction of the liquid crystal molecules LC are provided. A portion or a recess may be provided.

  (Modification 2) In the liquid crystal device 100, the convex portion or the concave portion provided in the counter electrode 23 is not limited to being provided in a portion facing the corner portions 15 d, 15 e, 15 f, 15 g of the pixel electrode 15. FIG. 13A is a schematic plan view showing the arrangement of convex portions or concave portions in the counter electrode of the modification, and FIG. 13B and FIG. 13C are cut along the line DD ′ in FIG. It is a schematic sectional drawing. The D-D ′ line is drawn in a direction along the flow direction of the liquid crystal molecules LC. For example, as shown in FIGS. 13A to 13C, the portion 23 d of the counter electrode 23 in which the convex portion 23 b and the concave portion 23 c are formed between the pixel electrodes 15 adjacent in the flow direction of the liquid crystal molecules LC in plan view. May be set. According to this, although the size of the portion 23d that inhibits the flow of the liquid crystal molecules LC is smaller than in the first to third embodiments, even if the convex portion 23b or the concave portion 23c is provided, it contributes to the display. The thickness of the liquid crystal layer 50 between the pixel electrode 15 and the counter electrode 23 to be changed does not vary. In other words, it is possible to reliably avoid a decrease in optical characteristics due to the provision of the convex portions 23b and the concave portions 23c. Note that, as shown in the first modification, the convex portion 23b or the concave portion 23c does not have to be provided for each pixel P, and corresponds to a pixel P located at a position separated from each other or on the outer peripheral side of the effective display area E. You may provide in the position to do.

  (Modification 3) In the liquid crystal device 100, the alignment films 18 and 24 for aligning the liquid crystal molecules LC having negative dielectric anisotropy substantially vertically are not limited to inorganic alignment films. For example, even when an organic alignment film such as polyimide is used, the liquid crystal molecules LC can be substantially vertically aligned, and the present invention can be applied.

(Modification 4) The liquid crystal device 100 to which the present invention is applicable is not limited to the substantially vertical alignment (VA) method in which the liquid crystal molecules LC have negative dielectric anisotropy. For example, the present invention can be applied to a TN (Twisted Nematic) method and an OCB (Optically Compensated Bend) method in which the liquid crystal molecules LC have positive dielectric anisotropy. The flow direction of the liquid crystal molecules LC in the TN mode is a synthesis direction of vectors of alignment processing performed so as to intersect each other in each of the pair of substrates. Therefore, for example, in FIG. 4, the orientation processing direction on the element substrate 10 side is a direction from left to right along the X direction, and the orientation processing direction on the counter substrate 20 side is a direction from bottom to top along the Y direction. Then, as described above, display unevenness occurs in the lower left and upper right of the display area E. Therefore, it is effective to provide a convex portion or a concave portion that inhibits the flow of the liquid crystal molecules LC even in the TN mode.
In the alignment process in the VA method or the OCB method, the liquid crystal molecules LC are uniaxially aligned in the tilt direction, so that ionic impurities are likely to be diffused and unevenly distributed in a specific direction due to the flow of the liquid crystal molecules LC. Therefore, by applying the present invention, the effect is more exhibited as compared with the TN system.

  (Modification 5) The liquid crystal device 100 to which the present invention is applicable is not limited to the transmissive type. For example, the present invention can also be applied to a reflective liquid crystal device in which the pixel electrode 15 is formed using a light reflective conductive film.

  (Modification 6) The electronic apparatus to which the liquid crystal device 100 can be applied is not limited to the projection display device 1000 of the second embodiment. For example, projection-type HUD (head-up display), direct-view type HMD (head-mounted display), electronic book, personal computer, digital still camera, LCD TV, viewfinder type or monitor direct-view type video recorder, car navigation system It can be suitably used as a display unit of an information terminal device such as an electronic notebook or POS.

  DESCRIPTION OF SYMBOLS 10 ... Element board | substrate as one board | substrate, 15 ... Pixel electrode, 15b ... Convex part, 15c ... Concave part, 15d, 15e, 15f, 15g ... Corner part of a pixel electrode, 20 ... Counter board | substrate as another board | substrate, 23 ... Counter electrode, 23b ... convex part, 23c ... concave part, 23d ... part of the counter electrode facing the corner of the pixel electrode, 30 ... thin film transistor (TFT), 50 ... liquid crystal layer, 100 ... liquid crystal device, 1000 ... electronic device Projection type display device, E ... display region, LC ... liquid crystal molecule.

Claims (9)

A pair of substrates;
A liquid crystal layer sandwiched between the pair of substrates;
A plurality of pixel electrodes on one of the pair of substrates;
A counter electrode facing the plurality of pixel electrodes on the other of the pair of substrates;
A liquid crystal, wherein at least one of the pixel electrode and the counter electrode is provided with a convex portion or a concave portion for inhibiting the flow of the liquid crystal molecules generated by driving the liquid crystal molecules of the liquid crystal layer. apparatus.   The liquid crystal device according to claim 1, wherein the convex portion or the concave portion is formed at least in a corner portion of the pixel electrode in a flow direction of the liquid crystal molecules.   2. The liquid crystal device according to claim 1, wherein the convex portion or the concave portion is formed in a portion of the counter electrode that faces at least a corner portion of the pixel electrode in a flow direction of the liquid crystal molecules.   2. The liquid crystal device according to claim 1, wherein the convex portion or the concave portion is formed in a portion of the counter electrode facing between the pixel electrodes adjacent in the flow direction of the liquid crystal molecules.   5. The liquid crystal device according to claim 1, wherein the convex portion or the concave portion is formed in an island shape and spaced apart from each other.   5. The liquid crystal device according to claim 1, wherein the convex portion or the concave portion is formed at intervals with respect to the plurality of pixel electrodes. 6.   The said convex part or recessed part is formed in the part of the said counter electrode which opposes the said pixel electrode located in the outer periphery of an effective display area, or the said pixel electrode, It is any one of Claim 1 thru | or 4 characterized by the above-mentioned. The liquid crystal device according to 1. A transistor provided corresponding to the pixel electrode;
A light shielding portion provided so as to overlap the transistor in a plane,
The liquid crystal device according to claim 1, wherein at least a part of the convex portion or the concave portion is provided at a position overlapping the light shielding portion.   An electronic apparatus comprising the liquid crystal device according to claim 1.

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