JP3493124B2 - Liquid crystal display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and in particular, a pair of insulating substrates are opposed to each other through a spacer with a constant gap, and the liquid crystal composition held in the gap is oriented in a predetermined direction. The present invention relates to a held liquid crystal display device.

[0002]

2. Description of the Related Art High-definition and color-displaying liquid crystal display devices for notebook computers and computer monitors have been widely used.

This liquid crystal display device basically constitutes a so-called liquid crystal panel by sandwiching a layer of a liquid crystal composition between two insulating substrates, at least one of which is a transparent glass plate or the like,
Various electrodes for forming pixels formed on the insulating substrate of the liquid crystal panel are selectively applied with voltage to change the alignment direction of liquid crystal molecules in a predetermined pixel portion to form pixels (simple matrix). And an active matrix for forming a pixel by forming an active element for pixel selection and selecting the active element to change the alignment direction of liquid crystal molecules of a predetermined pixel.

In general, an active matrix type liquid crystal display device is a so-called vertical electric field system in which an electric field for changing the alignment direction of a liquid crystal layer is applied between an electrode formed on one substrate and an electrode formed on the other substrate. Has been adopted.

On the other hand, a so-called lateral electric field type (also called IPS type) liquid crystal display device in which the direction of the electric field applied to the liquid crystal layer is substantially parallel to the substrate surface has been put into practical use. As a disclosure of this lateral electric field type liquid crystal display device, there is known one in which a comb-teeth electrode is used on one of two substrates to obtain a very wide viewing angle (Japanese Patent Publication No. 63-21).
907, U.S. Pat. No. 4,345,249).

In a liquid crystal panel used in this type of liquid crystal display device, a spacer is interposed in a gap filled with the liquid crystal composition between the pair of insulating substrates to keep the gap at a predetermined value.

As a conventional spacer, a spherical spacer made of a resin or a glass material is used, or a surface treatment such as a coloring agent, an adhesive agent, an alignment treatment agent or the like is applied to the inner spacer of the insulating substrate on the electrode substrate side. In general, it is sprayed by an electrostatic spraying method or a semi-dry spraying method.

Further, instead of the spherical spacers as described above, columnar spacers (projections) having a predetermined pattern are formed on at least a part of the region (non-pixel portion) shielded by the shield portion by a photolithography technique or a printing technique. It is also proposed to form (Japanese Patent Laid-Open No. 7-325298 and Japanese Patent Laid-Open No. 8-32598).
-286194 gazette).

After forming the spacers, an alignment film such as a polyimide resin is applied to cover the columnar spacers together with the electrodes or other functional films of the insulating substrate, and the liquid crystal is aligned in a predetermined direction on the surface of the alignment film. An alignment step for imparting controllability (generally referred to as a rubbing treatment, but recently, there is also a so-called photo-alignment treatment for imparting liquid crystal alignment controllability by irradiating a predetermined polarized light).

[0010]

However, when the spherical spacers are dispersed by the above-mentioned dispersion method, they are left on the electrode substrate, and light leakage from the spacer body or the periphery of the spacer occurs in the pixel region. However, there is a problem that the contrast of the displayed image is lowered, and the spacers move due to the unevenness of the dispersion, the vibration of the liquid crystal panel during the formation of the cells or the filling of the liquid crystal composition, or the impact during the transportation of the product. There is a problem that display quality is degraded due to display unevenness caused by unevenness of arrangement density (inner surface unevenness) and movement traces.

On the other hand, in the spacer selectively formed in the non-pixel portion of the electrode substrate by the photolithography technique or the printing method, since the arrangement is fixed to the non-pixel portion, there is a problem as in the case of using the spherical spacer. Does not happen. However, since the protrusions are formed in advance, in the alignment step performed after the formation of the alignment film, sufficient liquid crystal alignment controllability cannot be imparted to the peripheral portion of the protrusion as compared with other flat portions, resulting in As a result, the liquid crystal alignment is likely to be disturbed in the peripheral portion.

FIG. 13 is a schematic view for explaining a rubbing process which is a general method for imparting a required liquid crystal alignment controllability to an alignment film, wherein 1 is an insulating substrate, 20 is an alignment film, and 200 is. A rubbing roller, 105 is a rotating direction of the rubbing roller, and 107 is a traveling direction of the rubbing roller (a relative moving direction with respect to the insulating substrate 1).

The rubbing roller 200 wound with a buff cloth or a rubbing cloth with fibers is applied to the insulating substrate 1 coated with the alignment film 20 and dried, and the rubbing roller 200 is rotated in the direction of arrow 105 and relatively moved in the direction of arrow 107. By doing so, the orientation controllability is imparted to the surface of the orientation film 20.

At this time, if columnar protrusions are formed on the alignment film 20 as spacers, a portion (rubbing abnormal region) where rubbing is not performed occurs when the rubbing roller gets over the protrusions.

FIG. 14 is a schematic diagram for explaining the occurrence of a rubbing abnormal region when a protrusion is formed on the alignment film.
In the figure, 30 is a spacer (columnar protrusion), 106 and 108 are regions where rubbing is insufficient (liquid crystal alignment control inferior region: the above-mentioned rubbing abnormal region, hereinafter also referred to as rubbing shadow), and the same symbols as in FIG. Corresponding to.

FIG. 3A is an explanatory view of an abnormal rubbing region caused by the rubbing direction. When the rotation direction of the rubbing roller with respect to the spacer 30 is the direction shown by the arrow 105, the spacer 30 is in the above-mentioned state. A rubbing shadow indicated by a halftone dot 106 is generated on the downstream side in the rotation direction 105 of the rubbing roller. When the rubbing roller passes over the spacer 30, the rubbing shadow becomes larger than the other areas between the fibers of the rubbing roller and the alignment film, so that the alignment film cannot have the liquid crystal alignment control ability or is insufficient. It is because the rubbing is done.

Further, FIG. 3B is an explanatory diagram of an abnormal rubbing region caused by the traveling direction (relative movement direction to the alignment film) 107 of the rubbing roller, and the moving direction of the rubbing roller with respect to the spacer 30. Is in the direction indicated by the arrow 107, a rubbing abnormal region (rubbing shadow) indicated by a diagonal line 108 occurs on the downstream side of the spacer 30 in the moving direction 107 of the rubbing roller. This abnormal rubbing region 108 is due to the fact that when the rubbing roller passes over the spacer 30, the gap between the fiber of the rubbing roller and the alignment film becomes larger than the other regions, as in the case of (a) above.

FIG. 3C shows the abnormal rubbing regions shown in FIGS. 7A and 7B in an overlapping manner. The abnormal rubbing regions generated in the rubbing process are two directions with respect to the spacer 30. Will occur.

Such abnormal rubbing regions 106, 10
The length of 8 varies depending on the height of the spacer 30.

A similar problem arises in imparting liquid crystal controllability by photo-alignment treatment. That is, in the photo-alignment treatment, the molecular bonding state of the polarized light irradiation portion of the alignment film is changed by riding a predetermined polarized light at a certain angle with respect to the surface of the alignment film. The shadow of the spacer, which is generated because it is not perpendicular to the film surface, causes the same poor liquid crystal alignment controllability as the shadow in the rubbing direction of the rubbing process. In addition, in the following, since the liquid crystal alignment controllability defect due to such optical alignment is the same as the rubbing defect in the rubbing process, all the rubbing process will be described as an example.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a liquid crystal display device capable of obtaining good display quality by eliminating display defects such as a decrease in contrast and display unevenness due to spacers. To provide.

[0022]

FIG. 15 is an analysis diagram of the length of the abnormal rubbing region depending on the rubbing direction.
Is a schematic diagram showing the length a (μm) of the rubbing shadow and the vertical and horizontal components thereof that occur when the spacer 30 and the rubbing direction (105) and the moving direction 107 of the rubbing roller have an angle θ relationship. ) Is a diagram geometrically expressing the relationship of (a).

The length a of the rubbing shadow with respect to the height of the spacer (shown as a step) varies slightly depending on the rubbing conditions (cutting amount of the rubbing roller, rotation speed, feed speed: relative moving speed). The higher the height (step) is, the longer it becomes, and in the range of the inter-substrate gap (cell gap) of the current general liquid crystal cell of 3 to 6 μm (= step of spacer), the length becomes 50 to 100 μm.

Table 1 shows a measurement example of the step of the spacer and the length a of the rubbing shadow and its vertical component b and horizontal component c.

[0025]

[Table 1]

The present invention is characterized in that the spacers are arranged at such positions that the vertical component b and the horizontal component c are within the light-shielding area of the liquid crystal panel.

That is, in order to achieve the above-mentioned object, the present invention is characterized in that it has the constitution described in the following (1) to (4).

(1) A pair of opposing insulating substrates having a light-shielding means on at least one side, a pair of alignment films formed on each of the opposing surfaces of the pair of insulating substrates, and sandwiched between the pair of alignment films. In the liquid crystal display device for controlling the light transmissivity of liquid crystal molecules by a spacer and a liquid crystal composition for holding a facing gap between the pair of insulating substrates constant, and an electric field generated between the pixel electrode and the reference electrode, 1
Alternatively, the plurality of pixels are arranged in a lattice shape, and the spacer is arranged in a portion shielded by the lattice-shaped light shielding means.

The specific position of the spacer in the portion shielded by the light shielding means is determined by the rubbing direction. That is, the shadow due to rubbing (a region lacking in rubbing)
Is set to a position where most of them are within the area of the light shielding means.

According to this structure, the insufficient rubbing region due to the spacer interposed between the insulating substrates does not occur in the effective pixel region, the generation of the domain due to the abnormal rubbing of the alignment film is avoided, and the conventional structure is avoided. Spacer movement and light leakage that occur when the spherical spacer of (1) is used are suppressed, and a high quality liquid crystal display device can be obtained.

(2) The spacer in (1) is arranged at a position displaced from the center in the width direction of the light shielding means arranged in the lattice.

The specific disposition position of the spacer is a position displaced from the center of the light shielding means in the width direction to the upstream side in the rubbing direction. As a result, most of the shadow caused by rubbing is contained within the area of the light shielding means.

Therefore, the insufficient rubbing region due to the spacer does not occur in the effective pixel region, the generation of the domain due to the abnormal rubbing of the alignment film is avoided, and the spacer movement that occurs when the conventional spherical spacer is used. Thus, a liquid crystal display device with high image quality can be obtained in which light leakage is suppressed.

(3) The pixel electrode and the reference electrode in (1) are formed on one insulating substrate, and at least one organic film different from the alignment film is provided on the other insulating substrate. The spacer was formed integrally or separately from the same material as the organic film or the alignment film.

In this structure, by disposing the spacer on the side of the insulating substrate that does not have the pixel selection electrode such as the pixel electrode and the reference electrode, the flatness of the alignment film in the effective pixel region is good, and A spacer can be formed by using a patterning technique such as a photolithography method or a printing method at the same time or in a separate step of forming various organic films formed under the alignment film, and a new material for the spacer can be introduced. Instead, spacers can be arranged at a uniform height.

(4) The organic film in (3) is made of the same material as either the color filter layer or the flattening film formed on the color filter layer or the black matrix.

With this structure, a color filter or a flattening film (protective film) formed in the lower layer of the alignment film or a black matrix is formed at the same time as the color filter or the flattening film or the black matrix, or at the additional step. The spacers can be formed by using a patterning technique such as a lithography method or a printing method, and the spacers can be arranged at a uniform height without introducing a new material for the spacers. In particular, when the spacers are formed at the same time or in the additional step of forming the black matrix formed in the lower layer of the alignment film, the spacers can be arranged at a uniform height without introducing a new material for the spacers.

It is needless to say that the present invention can be similarly applied to a conventionally known vertical electric field type liquid crystal display device or a simple matrix type liquid crystal display device.

Further, the spacer is not limited to the one formed integrally with the above-mentioned various organic films, but a separately prepared spherical or columnar or other shaped granular body is fixed at a predetermined position. , A similar effect can be obtained. The black matrix is not limited to the one having a lattice shape surrounding the pixels, and the same may be applied to the one using a striped black matrix.

Further, the present invention is not limited to the rubbing treatment as a means for imparting the liquid crystal alignment controllability to the alignment film, and may be a so-called optical alignment treatment for irradiating the alignment film with polarized light having a predetermined polarization characteristic. It is valid.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to examples.

FIG. 1 is a schematic view of a planar structure of a plurality of pixels surrounded by a light-shielding film for explaining a main part structure of a liquid crystal display device according to the present invention.

In the figure, 10 is a pixel, 22 is a light-shielding film (hereinafter also referred to as black matrix), 30 is a spacer, 101 is a light-shielding portion symmetry point, 102 is a spacer symmetry point,
Reference numeral 103 denotes a light-shielding portion center line along the video signal line, and 104 denotes a light-shielding portion center line along the scanning signal line.

Pixel 10 shows one pixel each in the case of mono color, and shows each pixel of red (R), green (G) and blue (B) in the case of full color. The periphery of each pixel 10 is surrounded by a light shielding unit (black matrix) 22.

That is, the black matrix 22 is arranged in a lattice pattern surrounding a plurality of pixels, and in the portion where the black matrix 22 in the lattice pattern intersects, and at the center position of the intersection, that is, along the video signal line, the light is shielded. Center line 1
The spacer 30 is arranged so that its center (spacer symmetry point) 102 is located at a position displaced from the intersection point (symmetry point 101 of the light shield portion) of 03 and the light shield center line 104 along the scanning signal line.

The arrangement position of the spacer 30 is as shown in FIG.
4 and so-called rubbing shadow 106 as described in FIG.
And 108 are positions where the influence on the pixel area is small,
Details of the arrangement position will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a plan view of a main part for explaining the arrangement position of the spacers in the liquid crystal display device of the present invention, and FIG. 3 is an enlarged plan view of the main part for explaining FIG. 2 in more detail.

FIG. 2A is an explanatory diagram of a rubbing direction and its rubbing shadow imparted by the rotation of the rubbing roller, and FIG. 2B is an explanatory diagram of a moving direction of the rubbing roller and its rubbing shadow.

As shown in FIG. 2A, when the insulating substrate having the pixels 10 surrounded by the black matrix 22 is rubbed from the upper right direction to the lower left direction in the figure, a black grid pattern is formed. When the spacers are positioned at the intersections of the matrix 22, the rubbing shadow extends in the direction indicated by 109 in the figure.

Further, as shown in (b), when the rubbing roller is moved from the upper side to the lower side in the drawing with respect to the insulating substrate on which the pixels 10 surrounded by the black matrix 22 are formed, a grid pattern is formed. When the spacers are positioned at the intersections of the black matrixes 22 in FIG.
It extends in the direction indicated by 12.

Therefore, the portion where the rubbing shadow caused by the step of the spacer has little influence on the pixel 10 is located inside the intersection of the lattice-shaped black matrix 22 and displaced upward from the center of the intersection. . Then, the part that is least affected is the position displaced to the upper right from the center position of the intersection.

As shown in FIG. 3, the spacers are arranged at positions where the spacers are displaced above the center line 104 of the light shielding portion 113 along the video signal line and the scanning signal line at the intersection of the black matrix 22. It may be arranged in the intersection region 114 of the intersection region 114, and preferably, the region 115 on the right side of the light-shielding part center line 103 along the video signal line of the intersection region 114.
To place.

According to this structure, it is possible to reduce or eliminate the influence of the rubbing insufficient region caused by the spacer interposed between the insulating substrates in the effective pixel region (in the display surface), and the alignment film. The occurrence of domains due to the rubbing abnormality is prevented, and the spacer movement and light leakage that occur when the conventional spherical spacer is used are suppressed, so that a liquid crystal display device with high image quality can be obtained.

In the spacer of the present invention, the pixel electrode and the reference electrode are formed on one insulating substrate, and the other insulating substrate has at least one kind of organic film different from the alignment film. When applied to a so-called lateral electric field type liquid crystal display device in which an electric field is applied to a liquid crystal composition sandwiched between insulating substrates in a direction substantially parallel to the surface of the insulating substrate, it is formed on the other insulating substrate. It can be formed simultaneously with the formation of the organic film or the alignment film to be formed, or in an additional step. At this time, the spacer may be made of the same material as the organic film or the alignment film, or may be made of another appropriate organic material.

The organic film is any one of a color filter material, an alignment film material, a flattening film for reducing irregularities on the surface of the color filter, or a black matrix material, or a combination of two or more thereof. Material may be used.

As a method for forming a spacer with such an organic film, a known photolithography method, printing method, or other patterning technique can be used.

Next, specific examples of the liquid crystal display device according to the present invention will be described.

FIG. 4 is an explanatory diagram of an equivalent circuit of the liquid crystal display device according to the present invention. Reference numeral 300 denotes a liquid crystal panel, the display black of which is composed of a set of a plurality of pixels arranged in a matrix, and each of which is composed of a plurality of pixels. The pixel is an illumination light source (backlight: not shown) installed on the back of the liquid crystal panel 300.
It is configured so that the transmitted light from can be independently modulated and controlled.

The light modulation in each pixel adopts a method called a lateral electric field method, the structure of which will be described later, but the transparent substrate (insulating substrate) 100 arranged to face each other.
The electric field generated in the layer (liquid crystal layer) of the liquid crystal composition interposed between (1A, 1B) is set to be substantially parallel to the transparent substrates 1A, 1B.

Such a liquid crystal panel 300 is known as an excellent so-called wide viewing angle characteristic because it can recognize a clear image even when viewed from a large angle visual field with respect to its display surface. That is, of the transparent substrates 1A and 1B arranged to face each other with the liquid crystal layer of the liquid crystal panel 300 interposed therebetween,
A scanning signal line 2 and a reference signal line 4 that extend in the x direction (row direction) and are arranged in parallel in the y direction (column direction) are formed on the surface of one transparent substrate 1A on the liquid crystal layer side. There is.

In this case, in the figure, the scanning signal line 2, the reference signal line 4 arranged in the vicinity of the scanning signal line 2, and the reference signal line 4 are separated from the upper side of the transparent substrate 1A by a relatively large distance. , The reference signal lines 4 arranged in proximity to the scanning signal line 2, ...
They are arranged sequentially.

Video signal lines 3 are formed which are insulated from the scanning signal lines 2 and the reference signal lines 4 and extend in the y direction and are arranged in parallel in the x direction.

Here, unit pixels are formed in each rectangular area having a relatively large area surrounded by the scanning signal line 2, the reference signal line 4, and the video signal line 3, and these unit pixels are arranged in a matrix. Arranged to form the display surface. The detailed configuration of the pixel will be described later.

The liquid crystal panel 300 is provided with a vertical scanning circuit 5 and a video signal driving circuit 6 as its external circuits, and the vertical scanning circuit 5 sequentially scans signals (voltages) to each of the scanning signal lines 2. Is supplied, and the video signal (voltage) is supplied from the video signal drive circuit 6 to the video signal line 3 at the timing.

The vertical scanning circuit 5 and the video signal drive circuit 6 are supplied with power from the liquid crystal drive power supply circuit 7, and the image information (video information) from the CPU 8 is converted into display data and control signals by the controller 9. It is input separately.

A reference voltage (for example, a constant voltage) is supplied to the reference signal line 4 from the liquid crystal drive power supply circuit 7.

FIG. 5 is a plan view for explaining the peripheral structure of the unit pixel in FIG. 6 is a sectional view taken along line IV-IV of FIG. 5, FIG. 7 is a sectional view taken along line VV of FIG. 5,
FIG. 8 is a sectional view taken along line VI-VI of FIG.

In FIG. 5, x is formed on the main surface of the transparent substrate 1A.
The reference signal line 4 extending in the direction, and the scanning signal line 2 are formed in parallel with the reference signal line 4 in the y direction on the lower side in the drawing and are parallel to each other.

Here, the reference signal line 4 is integrally formed with three reference electrodes 14. That is, the two reference electrodes 14 among them are the sides in the y direction of the pixel region formed by a pair of video signal lines 3 described later, that is, the y on the lower side in the drawing in the vicinity of the respective video signal lines 3 described above. Formed to extend in the vicinity of the scanning signal line 2 in the direction, and the remaining one is formed between them.

The surface of the transparent substrate 1A on which the scanning signal lines 2, the reference signal lines 4 and the reference electrodes 14 are formed also covers the scanning signal lines 2 etc. and is made of, for example, a silicon nitride film. The film 15 (see FIGS. 6, 7, and 8) is formed. The insulating film 15 is provided for the scanning signal line 2 and the reference signal line 4 for the video signal line 3 described later.
As an interlayer insulating film for the intersection with and, it functions as a gate insulating film for the formation region of the thin film transistor TFT and as a dielectric film for the formation region of the storage capacitor Cstg.

On the surface of the insulating film 15, first, in the formation region of the thin film transistor TFT, the semiconductor layer 16 is formed.
Are formed. The semiconductor layer 16 is made of, for example, amorphous silicon (a-Si), and is formed so as to overlap with a portion of the scanning signal line 2 which is close to the video signal line 3. As a result, a part of the scanning signal line 2 also serves as the gate electrode of the thin film transistor TFT.

Then, the insulating film 15 thus formed
As shown in FIG. 5, the video signal lines 3 extending in the y direction and arranged in parallel in the x direction are formed on the surface of the.

The video signal line 3 is integrally provided with a drain electrode 3A formed by extending to a part of the surface of the semiconductor layer 16 of the thin film transistor TFT.

Further, a pixel electrode 18 is formed on the surface of the insulating film 15 in the pixel area. This pixel electrode 1
Reference numeral 8 is formed so as to run between the reference electrodes 14. That is, one end of the pixel electrode 18 also serves as the source electrode 18A of the thin film transistor TFT, extends as it is in the y direction on the upper side in the drawing, and further extends in the x direction along the reference signal line 4 and then in the drawing. It has a U-shape that extends in the y direction on the lower side and has the other end.

In this case, the portion of the pixel electrode 18 overlapping the reference signal line 4 constitutes a storage procedure Cstg including the insulating film 15 as a dielectric film between the pixel electrode 18 and the reference signal line 4. This storage procedure Cstg has an effect of storing video information in the pixel electrode 18 for a long time when the thin film transistor TFT is turned off, for example.

The surface of the semiconductor layer 16 corresponding to the interface between the drain electrode 3A and the source electrode 18A of the thin film transistor TFT described above is doped with phosphorus (P) to form a high-concentration layer. Ohmic contact is attempted at each electrode. In this case, the high-concentration layer is formed on the entire surface of the semiconductor layer 16, and after forming the electrodes, the high-concentration layer other than the electrode formation region is etched using the electrodes as a mask. The above-mentioned configuration can be adopted.

In this way, the thin film transistor TFT,
Video signal line 3, pixel electrode 18, and storage procedure Cstg
A protective film 19 made of, for example, a silicon nitride film (see FIGS. 6, 7, and 8) is formed on the upper surface of the insulating film 15 on which the alignment film 20A is formed. And constitutes a transparent substrate 1A of the liquid crystal panel 300. A polarizing plate 21A is laminated on the surface of the transparent substrate 1A opposite to the liquid crystal layer side.

Then, as shown in FIG. 6, the transparent substrate 1
In the portion B of the liquid crystal layer side, a black matrix 22 which is a light-shielding film is formed by dividing the display region into pixels. The black matrix 22 has a function of preventing direct irradiation of the thin film transistor TFT with light and a function of improving display contrast.

The black matrix 22 is formed in the region shown by the broken line in FIG. 5, and the formed opening forms a substantial pixel.

Further, a color filter 23 is formed so as to cover the opening of the black matrix 22. The color filter 23 has a color different from that of the pixel regions adjacent to each other in the x direction, and each has a boundary portion on the black matrix 22. A flattening film 24 made of a resin film or the like is deposited on the surface on which the color filter 23 is formed in this way. An alignment film 20B is formed on the surface of the flattening film 24. In addition,
A polarizing plate 21 is provided on the surface of the transparent substrate 1B opposite to the liquid crystal layer side.
B is arranged.

FIG. 9 is an explanatory view of the relationship between the optical axes of the alignment film 20A formed on the transparent substrate 1A side and the polarizing plate 21A, and the alignment film 29B formed on the transparent substrate 1B side and the polarizing plate 21B.

The angle of the rubbing direction 105 of the alignment films 20A and 20B with respect to the direction 120 of the electric field applied between the pixel electrode 18 and the reference electrode 14 is Φ _LC , and the polarization transmission of one polarizing plate 21A. The angle 121 in the axial direction is Φ _P ,
The polarization transmission axis direction of the other polarizing plate 21B is orthogonal to Φ _P. Also, Φ _LC = Φ _P.

The liquid crystal composition constituting the liquid crystal layer has a positive dielectric anisotropy Δε and its value is 7.3 (1 kHz),
Refractive index anisotropy Δn is 0.073 (589 nm, 20 °
The nematic liquid crystal of C) is used.

Alignment films 20A and 2 having such a relationship
0B, and the configuration of the polarizing plates 21A and 21B, etc., is so-called normally black mode, and an electric field E (see FIG. 6) parallel to the transparent substrate 1A is generated in the liquid crystal layer LC to generate the liquid crystal. The layer LC is adapted to transmit light. However, the present invention is not limited to the normally black mode lateral electric field type liquid crystal display device as described above, and the normally white mode in which the light transmitted through the liquid crystal layer at the time of no electric field is maximum, and the vertical electric field It goes without saying that the present invention can be similarly applied to the liquid crystal display device of the type.

FIG. 10 is an explanatory view of the spacer portion of the liquid crystal display device according to the present invention, in which (a) is a plan view of the main part,
(B) is a sectional view taken along the line AA of (a), and (c) is a sectional view taken along the line BB of (a).

The black matrix 2 is formed on the transparent substrate 1B.
2. A color filter 23 is patterned, and a flattening film 24 and an alignment film 21 are formed to cover them.
The organic film of B is formed.

A spacer 30 is formed on a part of the black matrix portion. Here, the spacer 30
Is formed of the same material as the flattening film 24, but may be formed of the same material as the color filter 23 which is an organic film, the alignment film 21B, or the black matrix 22. Further, the spacer 30 and the flattening film 24, the color filter 23, the alignment film 21B, or the black matrix 22 may be made of a different material.

In the liquid crystal display device having the spacer thus configured, the spacer interposed between the transparent substrates 1A and 1B is arranged on one transparent substrate 1B side at the position described with reference to FIGS. Therefore, the alignment film 20B does not cause alignment failure due to rubbing, and the spacer 3
Since 0 is fixed to the transparent substrate 1B, the spacer does not move.

Further, since the spacer 30 is formed at a position overlapping the black matrix 22, the light leakage phenomenon due to the alignment disorder of the liquid crystal around the spacer does not affect the display quality, and an image of good quality is obtained. You can get the display.

Although the spacer 30 is formed on the transparent substrate 1B side in the above description, it is not limited to this and may be formed on the protective film 19 or the alignment film 20A side formed on the transparent substrate 1A side.

FIG. 11 is a developed perspective view for explaining an example of the overall structure of a liquid crystal display device to which the present invention is applied.

The figure shows a liquid crystal display device (hereinafter, a liquid crystal panel,
A specific structural example of a module (referred to as MDL) in which a circuit board, a backlight, and other components are integrated will be described.

In FIG. 11, SHD is a shield case (also referred to as a metal frame) made of a metal plate, WD is a display window, INS1 to 3 are insulating sheets, PCBs 1 to 3 are circuit boards (PCB1 is a drain side circuit board: video signal). Line driving circuit board, PCB2 is a gate side circuit board, PCB3 is an interface circuit board), and JN1 to JN3 are circuit boards P
Joiner, TCP that electrically connects CB1 to 3
1, TCP2 is a tape carrier package, PNL is a liquid crystal panel, GC is a rubber cushion, ILS is a light-shielding spacer, PRS is a prism sheet, SPS is a diffusion sheet, G
LB is a light guide plate, RFS is a reflection sheet, MCA is a lower case (mold frame) formed by integral molding,
LP is a linear lamp, LPC is a lamp cable, GB is a rubber bush that supports the linear lamp LP, BAT is a double-sided adhesive tape, BL is a backlight composed of the linear lamp LP, the light guide plate GLB, and the like. Therefore, the liquid crystal display module MDL is assembled by stacking the diffusion plate members.

The liquid crystal display module MDL has two kinds of housing / holding members, a lower case MCA and a shield case SHD, and has insulating sheets INS1 to INS3 and circuit boards PCB1 to PCB1.
3. A metal shield case SHD accommodating and fixing the liquid crystal panel PNL and a lower case MCA accommodating a backlight BL including a linear lamp LP, a light guide plate GLB, a prism sheet PRS and the like are combined.

The drain side circuit board PCB1 has an integrated circuit chip (I) for driving each pixel of the liquid crystal panel PNL.
C) is mounted, and interface circuit board PCB
3 includes an integrated circuit chip that receives a video signal from an external host, a control signal such as a timing signal, and a timing converter TCON that processes a timing to generate a clock signal.

The clock signal generated by the timing converter is supplied to the integrated circuit chip mounted on the drain side circuit board PCB1 through the clock signal line CLL laid on the interface circuit board PCB3 and the drain side circuit board PCB1. .

The interface circuit board PCB3 and the drain side circuit board PCB1 are multilayer wiring boards, and the clock signal line CLL is formed as an inner layer wiring of the interface circuit board PCB3 and the drain side circuit board PCB1.

In the liquid crystal panel PNL, the drain side circuit board PCB1 for driving the TFT, the gate side circuit board PCB2 and the interface circuit board PCB3.
Are connected by tape carrier packages TCP1, TCP2, and the respective circuit boards are connected by joiners JN1, 2, 3.

FIG. 12 is a perspective view of a notebook computer for explaining a mounting example of the liquid crystal display device according to the present invention.

This notebook type computer (portable personal computer) comprises a keyboard portion (main body portion) and a display portion connected to the keyboard portion by a hinge. Keyboard, host (host computer), CP
A signal generating function such as U is stored, and a liquid crystal panel P is provided on the display unit.
NL has drive circuit boards PCB1 and PCB around it
2. PCB3 with control chip TCON,
Also, an inverter power supply board, which is a backlight power supply, is mounted.

The structure described in the above embodiment is used as the spacer of the liquid crystal panel PNL.

As described above, according to the above-described embodiment of the present invention, it is possible to reduce or eliminate the influence of the rubbing insufficient region caused by the spacer interposed between the insulating substrates in the effective pixel region. Therefore, the occurrence of domains due to the rubbing abnormality of the alignment film is avoided, the spacer movement and light leakage that occur when the conventional spherical spacer is used are suppressed, and a liquid crystal display device with high image quality can be obtained.

In the above-described embodiments, the case where the spacers are arranged in the intersections of the black matrix has been described, but the present invention is not limited to this, and it is in the region shielded by the black matrix and by the rubbing treatment. It suffices that the shadow (rubbing defective region: liquid crystal alignment control defective region) is located at a position where most of the shadow falls within the region shielded by the black matrix. That is, by arranging the spacer at a position displaced in the width direction of the black matrix from the central portion in the width direction to the upstream side with respect to the rubbing direction, the occurrence of domains due to the rubbing abnormality of the alignment film is avoided, Spacer movement and light leakage that occur when a conventional spherical spacer is used are suppressed, and a liquid crystal display device with high image quality can be obtained.

In the above embodiment, the rubbing direction (liquid crystal orientation controllability direction) is from the upper right to the lower left in the figure, but it goes without saying that it is not limited to this direction.

[0105]

As described above, according to the present invention,
Since the adverse effect on the display due to the liquid crystal alignment controllability defective region generated in the effective pixel region by the spacer interposed between the insulating substrates can be reduced or eliminated, the liquid crystal alignment controllability of the alignment film can be provided. It is possible to avoid generation of domains due to abnormal processing, suppress spacer movement and light leakage that occur when a conventional spherical spacer is used, and obtain a liquid crystal display device with high image quality.

[Brief description of drawings]

FIG. 1 is a schematic view of a planar structure of a plurality of pixels surrounded by a light-shielding film for explaining a main part structure of a liquid crystal display device according to the present invention.

FIG. 2 is a plan view of relevant parts for explaining the arrangement position of spacers in the liquid crystal display device of the present invention.

FIG. 3 is an enlarged plan view of an essential part for explaining FIG. 2 in more detail.

FIG. 4 is an explanatory diagram of an equivalent circuit of the liquid crystal display device according to the present invention.

5 is a plan view illustrating a peripheral structure of the unit pixel in FIG.

6 is a sectional view taken along line IV-IV in FIG.

7 is a cross-sectional view taken along the line VV of FIG.

8 is a sectional view taken along line VI-VI of FIG.

FIG. 9 is an explanatory diagram of a relationship between an alignment film formed on one transparent substrate side and a polarizing plate, and an optical axis of an alignment film formed on the other transparent substrate side and a polarizing plate.

FIG. 10 is an explanatory diagram of a spacer portion of the liquid crystal display device according to the present invention, in which (a) is a plan view of relevant parts.

FIG. 11 is a developed perspective view illustrating an example of the overall configuration of a liquid crystal display device to which the present invention is applied.

FIG. 12 is a perspective view of a notebook computer for explaining a mounting example of the liquid crystal display device according to the present invention.

FIG. 13 is a schematic view illustrating a rubbing process step which is a general method for imparting a required liquid crystal alignment controllability to an alignment film.

FIG. 14 is a schematic diagram illustrating the occurrence of a rubbing abnormal region when a protrusion is formed on the alignment film.

FIG. 15 is an analysis diagram of the length of the abnormal rubbing region depending on the rubbing direction.

[Explanation of symbols]

10 pixels 22 Light-shielding film (black matrix) 30 spacers 101 Light shielding part symmetry point 102 Spacer symmetry point 103 Shade center line along video signal line 104 Shading center line along the scanning signal line 105 rubbing direction 106,108 rubbing shadow 107 Rubbing roller movement direction 110 Light part above the center line of the light shielding part along the scanning signal line 111 right area 113 Shading part along the video signal line 114 Suitable area 115 Optimal area.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-203925 (JP, A) JP-A-9-73088 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/1339 500 G02F 1/1335 500 G02F 1/1337 520 G02F 1/1365

Claims (4)

(57) [Claims] 1. A pair of opposing insulating substrates having light-shielding means on at least one side, a pair of alignment films formed on each of the opposing surfaces of the pair of insulating substrates, and sandwiched between the pair of alignment films. In a liquid crystal display device having a spacer and a liquid crystal composition that keep a facing gap between the pair of insulating substrates constant, the light shielding unit is arranged in a lattice shape surrounding one or a plurality of pixels, and the spacer is in the lattice shape. The spacer is arranged in a portion shielded from light by the light shielding means , and the spacer is
Move the bing roller downward from above the insulating substrate
While rotating the rubbing roller from the upper right direction
When rubbing in the lower left direction, the resulting rabbi
In order to reduce the influence of the shadow,
Within the intersection, the center of the intersection was displaced to the upper right.
A liquid crystal display device, which is formed at a position . 2. The liquid crystal display according to claim 1, wherein the spacer is arranged at a position displaced from a center portion in a width direction of the light shielding means arranged in the lattice shape. apparatus. 3. A pixel electrode and a reference electrode are formed on one insulating substrate, at least one kind of organic film different from the alignment film is provided on the other insulating substrate, and the spacer is the organic film or The liquid crystal display device according to claim 1, wherein the alignment film is formed of the same material as one body or a separate body. 4. The organic film is made of the same material as any one of a color filter layer, a flattening film formed on the color filter layer, and a black matrix.
The liquid crystal display device according to item 1.