JP3301381B2 - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to embody a wide visual field angle with a high-fineness direct viewing type display by forming liquid crystals as vertical alignment layers and subjecting the liquid crystals to impressed driving in such a manner that the potential difference between adjacent pixels attains the threshold voltage of liquid driving or above at all times. SOLUTION: When the alignment layers formed by forming polyimide precursor forms, by heating and baking are used after a polyimide precursor film is formed, the homeotropic alignment vertically aligned to a substrate is obtd. When the voltage V2 higher than the threshold Vth at which the liquid crystals start moving is impressed on pixel electrodes 4, the electric fields at pixel ends are offset to a diagonal direction from the normal direction of the substrates and the liquid crystals 13 are aligned in the direction coincident with the equipotential surface of the synthesized electric field by the synthesized electric field of the electric field between the upper and lower substrates and the adjacent pixels. The liquid crystals 13 in the pixel central parts are also aligned in follow up to the alignment direction of the liquid crystals 13 at the pixel ends. Since the driving of the liquid crystal molecules in the specific direction is thus made possible, the need for such a process, which arrays the liquid crystal molecules by previously applying regulating force in the specific direction, is eliminated.

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 (liquid crystal light valve) or a backlight used in a liquid crystal projector for irradiating light from a white light source onto a liquid crystal display device and projecting an image of the liquid crystal display device on a screen. The present invention relates to a liquid crystal display device (direct-view type liquid crystal display) that irradiates the liquid crystal display device with irradiation light from the device and directly observes an image of the liquid crystal display device.

[0002]

2. Description of the Related Art There is a growing need for higher definition liquid crystal projectors and smaller devices. At present, liquid crystal projectors using transmissive panels have been put into practical use. However, in order to respond to the demand for smaller and higher definition liquid crystal projectors in the future, liquid crystal light valves, which are liquid crystal display elements in liquid crystal projectors, It is necessary to reduce the size and increase the definition. However, in that case, it is inevitable that the ratio of the area through which light per pixel passes (hereinafter, referred to as the aperture ratio) is greatly reduced.

On the other hand, when the liquid crystal light valve is of a reflection type, almost the entire area of the pixel can be used as an effective reflection surface. Therefore, even when the liquid crystal light valve is miniaturized or has a high definition, the aperture ratio is low. The drop is significantly smaller than that of the transmission type.

Therefore, by using a reflection type liquid crystal light valve, a small and high-definition liquid crystal projector can be realized without lowering the luminance.

On the other hand, in a direct-view type liquid crystal display, in order to realize a truly paperless display, a high-definition display of 200 to 300 dots per inch or more, which is comparable to a printed matter, and has a bright and wide viewing angle. There is a demand for a display capable of performing the above. In a direct-view liquid crystal display, a transmissive display using a backlight is generally used in order to secure sufficient color reproducibility and brightness.

A homeotropic ECB (Electrically) is used as a liquid crystal display mode most suitable for a reflection type liquid crystal light valve or a direct view type liquid crystal display having a wide viewing angle.
Controlled Birefringence) mode. The liquid crystal alignment in the homeotropic ECB mode is a so-called homeotropic alignment in which the liquid crystal is aligned almost perpendicular to the substrate. As the liquid crystal material, a material having a negative dielectric anisotropy is used. In the homeotropic ECB mode, by applying a voltage between the upper and lower substrates, the long axis of the liquid crystal molecules is shifted from the normal direction of the substrate to generate birefringence, thereby changing the reflectance or transmittance of incident polarized light. This is a display mode for displaying images. In this method, it is necessary to define a certain direction in which the liquid crystal molecules fall from the normal direction of the substrate by some method. Conventionally, a combination of an island-like graded silicon oxide film formed on the substrate surface and a vertical alignment film is used so that the liquid crystal alignment at the substrate interface is slightly inclined from the normal direction of the substrate by oblique deposition. I have been. However, the oblique deposition method has a problem in mass productivity and is not practical.

Alternatively, it is possible to control the tilt angle of the liquid crystal at the interface of the substrate by ordinary rubbing so as to exert a regulating force in a specific direction from the normal direction of the substrate. It is very difficult to get. The non-uniform tilt angle causes threshold voltage unevenness and is observed as streak-like unevenness in a displayed image. This problem is a serious problem in a liquid crystal display, such as a liquid crystal projector, which displays an image of a liquid crystal light valve with a magnification of several tens of times.

Further, rubbing causes a failure due to destruction of a transistor due to static electricity and generation of debris of an alignment film, which is a major cause of a reduction in yield.

The liquid crystal orientation obtained by rubbing or oblique evaporation is a single domain, that is, a so-called monodomain. In a direct-view type liquid crystal display, problems such as a change in chromaticity occur depending on visual observation from a specific direction. This is because the anisotropy of the liquid crystal alignment becomes remarkable in a specific direction. Conventionally, in order to solve this problem, attempts have been made to realize a wide viewing angle by averaging the anisotropy of liquid crystal alignment by generating a plurality of domains, so-called multi-domains, in one pixel. I have. As a method for forming a multi-domain, mask rubbing, a photo-alignment method and the like have been attempted, but none of these methods is practical.

[0010]

As described above, the rubbing process has various problems, and the elimination of the rubbing process is very important for improving the mass productivity, reducing the price, and improving the display performance. effective.

Therefore, the present invention proposes a liquid crystal display element which does not require a rubbing step in order to solve various problems caused by the oblique deposition and rubbing steps which are the conventional liquid crystal alignment steps as described above. is there.

In particular, it is an object of the present invention to eliminate the need for an orientation control step such as oblique deposition or rubbing step in a liquid crystal display that will be further refined in the future.

In a direct-view display,
In order to approach the display performance of paper, it is desired that brightness, color reproducibility, etc. be high at the same time, high viewing angle, wide viewing angle, and the like.

One of the objects of the present invention is to realize a wide viewing angle in a high-definition direct-view display.

[0015]

The object of the present invention is to provide a pair of substrates, at least one of which is transparent at least at a predetermined interval and sandwiches a common electrode and a plurality of pixel electrodes arranged in rows and columns. In a liquid crystal display element comprising a liquid crystal layer held at the predetermined interval between the pair of substrates and an alignment control film formed on a surface of the pair of substrates that is in contact with the liquid crystal layer, the alignment control film Is a vertical alignment film that aligns the liquid crystal almost vertically to the substrate, and applies a voltage to each pixel so that the potential difference between adjacent pixels in the column or row direction is always equal to or higher than the threshold voltage for driving the liquid crystal. This is achieved by configuring to drive.

One of the specific methods is a liquid crystal driving method in which the polarity of the liquid crystal driving voltage is inverted with respect to a common potential between adjacent pixels and driven.

Further, according to the embodiment of the present invention, a common potential is applied between a layer forming a scanning line for controlling on / off of a signal line for supplying an image signal and a switching transistor of a pixel and a layer forming a pixel electrode. The power supply layer is arranged.

According to an embodiment of the present invention, the ratio of the pixel arrangement pitch to the predetermined distance between the substrates is 30: 1 or less.

The distance between adjacent pixel electrodes may be smaller than a predetermined distance between the substrates.

According to an embodiment of the present invention, a slit may be provided at a position corresponding to the center of a pixel on a substrate provided with a transparent electrode supplied with a common potential.

According to an embodiment of the present invention, a projection may be provided at a position corresponding to the center of a pixel on a substrate provided with a transparent electrode fed to a common potential.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The specific structure of the embodiment will be described below.

Embodiment 1 FIG. 1 is a schematic sectional view of a cell of a liquid crystal display element according to this embodiment. FIG. 2 is an enlarged top view of the pixel portion of the liquid crystal light valve of the present invention. FIG. 1 shows a cross section taken along the line AA 'in FIG.

The liquid crystal display device of the present embodiment has the following structure. The reflection type active matrix substrate 1 which is the first substrate drives the active element 3 and the pixel electrode 4 which also serves as a reflection plate and an active element 3 independently arranged on a single crystal silicon substrate 2. A wiring layer 24 composed of signal wiring and wiring for electrically connecting the pixel electrode to the active element, an insulating layer 5 as a protective film, a spacer 6 for uniformly maintaining a cell gap, and an alignment control film 8; And the opposing glass substrate 9, which is the second substrate,
A liquid crystal display comprising a transparent electrode 11 and an orientation control film 12 formed on a glass substrate 10, and a liquid crystal layer 13 containing a plurality of compounds interposed between the reflective active matrix substrate 1 and the opposing glass substrate 9. Configure the element.

Here, the configuration of the reflection type active matrix substrate 1 will be described in detail. The active matrix substrate of the present invention is formed on a silicon wafer,
It is formed by a semiconductor process on a normal silicon wafer. The reflection type active matrix substrate 1
Are MOS (Metal OxideS) as active elements for driving liquid crystal
(emiconductor) A transistor using a source diffusion layer 14, a source electrode 15, a drain diffusion layer 16, and a drain electrode 17 formed on a silicon substrate 2 and a p-type well.
And a polysilicon gate 18 to form a MOS transistor. Further, a storage capacitor 19 is provided between the source electrode 15 and the silicon substrate 2. A spin-on-glass insulating layer 22 is provided for interlayer insulation.

A candidate for the material of the pixel electrode 4 is a metal having a good reflectance in the visible light region, such as aluminum or silver. Here, an example in which aluminum is used as the material of the pixel electrode 4 will be described.
When the pixel electrode 4 is formed on a flat surface, a stable film can be formed and good reflection characteristics can be obtained. Therefore, the insulating layer 23 provided as a base of the pixel electrode is polished to a flat surface. It is desirable to make it. The pixel electrode 4 was formed by a sputtering method, and its thickness was 0.2 μm.

The reflection type active matrix substrate 1
In addition to these pixel structures, a peripheral drive comprising a clock signal line, an image signal line, a switching transistor for sampling an image signal, and a shift register circuit for scanning the sampling timing in synchronization with the clock signal. The circuit is formed on the same substrate.

An electric field shielding electrode layer 25 to which a common potential is supplied is provided between the pixel electrode 4 and a wiring layer including signal lines such as the drain electrode 17 and the gate electrode 18. this is,
In addition to blocking the effect of signal line potential fluctuations on the liquid crystal alignment, light conduction to the liquid crystal display element enters the substrate from between the pixel electrodes and irradiates the diffusion area with light, resulting in photoconductive accumulation. This has the effect of preventing charge leakage.

An insulating layer 5 is provided between the pixel electrode 4 and the alignment control film 8 as a protective film. As the insulating layer 5, for example, a silicon nitride film is used. The insulating layer 5 is formed by plasma CVD (Chem).
ical Vapor Deposition) method, and the thickness was 0.12 microns. An electric signal controlled by a MOS transistor, which is an active element, is applied to the pixel electrode 4 through a through-hole contact 20, and the opposing transparent electrode 1
1 to drive the liquid crystal layer 13.

As will be described later, a rubbing step is unnecessary in the present invention, so that a spacer formed by a photoetching step can be provided on a substrate. If a rubbing step is applied to a substrate on which a spacer formed by a photoetching step is formed, there is a possibility that the spacer shape is deformed or a region that is not rubbed as a shadow of the spacer is generated, but the rubbing step is not required in the present invention. Therefore, the above problem does not occur.

As a material of the spacer, PIQ-6200 manufactured by Hitachi Chemical Co., Ltd., which is a polyimide organic compound, was used. Hereinafter, this material is referred to as PIQ for convenience. PIQ as a spacer material was applied by spin coating. The film thickness was 2 microns. Then, 90 ° C for 3 minutes, 180 ° C
Drying and baking were performed stepwise under the conditions of 3 minutes and 350 ° C. for 2 minutes. Further, the pattern of the spacer is exposed by a photo process, and regions other than the spacer are removed by etching,
A 2 micron high spacer was formed.

Subsequently, a solution having a concentration of 5% of polyamic acid as a precursor of the orientation control film was applied by spin coating. The precursor of the orientation control film is a polyamic acid which is a polyimide precursor, and the monomer component is a 1,2-diamine compound containing a long-chain alkyl group as a diamine compound.
Using a mixture of diamine octadecane and p-phenylenediamine at a molar ratio of 1: 9, 1,2,3,4
-Butanetetracarboxylic dianhydride and 1,2,3,4
-Synthesized as a polyamic acid to an acid anhydride of cyclobutanetetracarboxylic dianhydride. After forming the polyimide precursor film, imidization was performed by heating and baking. When the present alignment film is used, a so-called homeotropic alignment in which the alignment is perpendicular to the substrate is obtained.

The active matrix substrate of the present invention has a configuration as described above.

As the liquid crystal layer 13, a nematic liquid crystal material having a negative dielectric anisotropy, in which a plurality of compounds are composed, is used. The value of the dielectric anisotropy Δε is -4.6, and the refractive index anisotropy Δn is 0.1.
49.

The manner in which the liquid crystal is driven will be described with reference to FIGS. 3 and 4 are schematic views of a cross section of the liquid crystal display device of the present invention. In FIG. 1, for simplicity, the structure below the pixel electrode 4 and the alignment control film 8 and the like described in FIG. 1 are omitted. Further, in practice, dot inversion driving in which a signal voltage whose polarity is inverted with respect to a common potential is performed between pixels adjacent in the row and column directions is performed. However, for simplicity, FIG. An example of the case of every inversion or every row inversion drive has been described. V ₁ and V ₂ which are the voltages applied to the pixel electrodes
Are in a relationship of V ₁ <V ₂ . Further, V ₁ was set to be equal to or lower than the threshold voltage (V _th ) at which the liquid crystal started to move. Therefore, when the voltage applied to the pixel electrode is ± V ₁ , the liquid crystal molecules are oriented almost perpendicular to the substrate as shown in FIG. Between adjacent pixels twice the voltage of the voltages V ₁ between the upper and lower substrates (2 ×
V ₁ ) is applied to the substrate almost horizontally, but the liquid crystal having a negative dielectric anisotropy is oriented so that the major axes of the liquid crystal molecules are aligned with respect to the equipotential surface. It is oriented almost perpendicular to the substrate.

Subsequently, when a voltage V ₂ higher than V _th is applied to the pixel electrode, a liquid crystal alignment as shown in FIG. 4 is obtained. Due to the combined electric field of the electric field between the upper and lower substrates and the electric field between adjacent pixels, the electric field at the pixel end shifts obliquely from the normal direction of the substrate, and the liquid crystal is aligned in a direction aligned with the equipotential surface of the combined electric field. The liquid crystal at the center of the pixel also aligns following the alignment direction of the liquid crystal at the edge of the pixel. However, since the liquid crystal molecules fall from both ends of the pixel toward the center, a domain wall is generated at the center of the pixel as shown in FIG. As described above, the liquid crystal molecules can be driven in a specific direction by the combined electric field of the electric field between the upper and lower substrates and the electric field between the adjacent pixels. The process of giving and arranging could be eliminated.

FIG. 5 shows an image generated in the pixel portion when the liquid crystal drive is performed. As described above, since the dot inversion drive for applying the signal voltage of which the polarity is inverted with respect to the common potential is performed between the pixels adjacent in the row and column directions, four domains are generated in one pixel. The wall of each domain is as shown in FIG. The shape of the domain wall varies depending on the pixel pitch or the cell gap.

When a liquid crystal light valve having a diagonal of 1 inch and the number of pixels of 1024.times.768 was prototyped with the above configuration, a display image obtained a contrast ratio of 300: 1 or more. FIG. 6 shows an applied voltage-luminance characteristic curve of this element. The applied voltages V ₁ and V ₂ in FIGS. 3 and 4 are voltages corresponding to V ₁ and V ₂ in the characteristic curve of FIG.

FIG. 7 shows the relationship between the ratio between the pixel pitch and the cell gap, the light use efficiency, and the liquid crystal response speed. Light utilization efficiency and liquid crystal response speed are determined by the balance between the electric field between the upper and lower substrates and the electric field between adjacent pixels when the cell gap is constant. That is, the ratio A between the pixel pitch and the cell gap is an important parameter. When a voltage is applied, the liquid crystal near the edge of the pixel is affected by the electric field that combines the electric field between the pixel and the electric field between the upper and lower substrates. Make a change. When A is large, the response speed required for propagating the orientation change from the pixel end to the pixel center decreases. Alternatively, when A is small, the influence of the electric field between the pixels is greater than the electric field between the upper and lower substrates, which acts on the liquid crystal alignment. Therefore, the angle at which the liquid crystal molecules fall from the substrate normal direction is large. In comparison, the desired birefringence cannot be obtained, and the light use efficiency decreases.

As a result of trial production with various ratios between the pixel pitch and the cell gap, the optimum ratio between the pixel pitch and the cell gap for obtaining sufficient light use efficiency and liquid crystal response speed is from 10: 1. It was found that the ratio was about 30: 1.

(Embodiment 2) FIG. 8 is an enlarged cross-sectional view of a pixel portion of this embodiment. FIG. 9 is an enlarged top view of the pixel portion of this embodiment. In FIG. 9, the substrate on the color filter side is omitted for simplicity.

In a liquid crystal display with a high definition of 150 to 300 dpi or more, the wiring pitch becomes the same definition, and it becomes difficult to connect the external drive circuit to the wiring. Therefore, a polycrystalline silicon TFT (Thin Film Transistor) is used.
Generally, a method of incorporating the peripheral drive circuit configured in r) into a substrate is used. Therefore, also in the present invention, an active matrix substrate was formed using a polycrystalline silicon TFT.

The liquid crystal display device of the present embodiment has the following structure. An active matrix substrate 41, which is a first substrate, includes an active element 43, a pixel electrode 46, and signal wiring (a drain line 44, a gate line 45) for driving the active element 43, each of which is independently disposed on a glass substrate 42. ), A wiring layer including a wiring 47 for electrically connecting the pixel electrode 46 and the active element 43 and the like, an insulating film (48, 49, 50) as a protective film, and a spacer for uniformly maintaining a cell gap. (Omitted in the figure) and the orientation control film 51
And a counter glass substrate 52 as a second substrate.
Denotes a black matrix 5 formed on a glass substrate 53
4, a color filter 55, an overcoat film 56, a transparent electrode 57, and an alignment control film 58. A liquid crystal layer 59 containing a plurality of compounds is sandwiched between the active matrix substrate 41 and the counter glass substrate 52. A transmission type liquid crystal display element is formed.

Here, the active matrix substrate 41
Will be described in detail. The active matrix substrate 41 of the present invention is formed on a glass substrate.
The active matrix substrate 41 uses a TFT as an active element for driving a liquid crystal, and has a source diffusion layer and a drain diffusion layer formed on a polycrystallized polysilicon layer 60 by annealing an island-shaped amorphous silicon layer with an excimer laser. Layer, source electrode 47, and drain line 44
And MOS (MetalOxide Semic
Onductor) An active element 43 was formed.

The reflection type active matrix substrate 1
In addition to these pixel structures, a peripheral drive comprising a clock signal line, an image signal line, a switching transistor for sampling an image signal, and a shift register circuit for scanning the sampling timing in synchronization with the clock signal. The circuit is formed on the same substrate.

In a direct-view display, one pixel is generally divided vertically into three picture elements corresponding to the three primary colors in order to perform color display. Therefore, one picture element has a length of 1/3 in the column direction with respect to the row direction. In the present invention, driving is performed in which the polarity of the image signal is inverted with respect to the common potential for each column, that is, a horizontal electric field between pixels is generated in the short side direction of the picture element.

The time required for scanning one row is referred to as a 1H period. The time required to scan one frame is referred to as a 1F period. An image signal whose polarity is inverted with respect to the common potential is applied to the drain line 44 every 1H period. A gate selection voltage is applied to the gate line 45 every 1F period. If the electric field between pixels is affected by the voltage of the drain line 44 and / or the gate line 45, uniform liquid crystal alignment cannot be obtained. Therefore, in order to prevent the electric field between the pixels from being affected by the electric field from the drain line 44 and the gate line 45, the pixel electrode 46 and the drain line 44
An electric field shielding layer 62 for supplying a common potential of an image signal is newly added between the gate line 45 and the gate line 45.

As the material for the orientation control film, the same material as that used in Example 1 was used. As a liquid crystal composition, a nematic liquid crystal having a negative dielectric anisotropy was used. The value of the dielectric anisotropy Δε is −4.2, and the refractive index anisotropy Δn is 0.083.

As a basic performance required for a direct-view display, a wide viewing angle is an important item. According to the configuration of the present invention, a plurality of domains, that is, a so-called multi-domain can be realized in one pixel. Since the anisotropy of the liquid crystal alignment is averaged by the multi-domain, a wide viewing angle can be realized.

Since rubbing is unnecessary in the method of the present invention, there is no problem that the transistor is damaged by static electricity or rubbing dust is generated. In particular, in a polysilicon panel in which a driving circuit is built in a peripheral portion of a pixel, a transistor used for the driving circuit is easily affected by static electricity. (Embodiment 3) FIG. 10 is an enlarged sectional view of a pixel portion of this embodiment. FIG. 11 is an enlarged top view of the pixel portion of this embodiment. In FIG. 11, for the sake of simplicity, parts other than the slit 63 provided in the transparent electrode 57 of the substrate on the color filter side described later are omitted.

In the present embodiment, in addition to the embodiment 2, a slit 63 is provided at a position corresponding to the center of the pixel of the transparent electrode 57 on the substrate on the color filter side.

The area where the slit 63 is located is
In the multi-domain generated in the pixel by the driving method of the present invention, the domain wall generated between the domains is located at the position of the slit 63 because the voltage applied between the substrate 52 and the substrate 52 is locally small. It has the effect of pinning. By pinning the domain wall at a predetermined position, the size of each domain region in the multi-domain can be uniquely determined, so that the symmetry of the viewing angle can be more strictly controlled.

(Embodiment 4) FIG. 12 is an enlarged cross-sectional view of a pixel portion of this embodiment. FIG. 13 is an enlarged top view of the pixel portion of this embodiment. In FIG. 13, for simplicity, illustrations other than projections 64 provided on the transparent electrode 57 of the substrate on the color filter side described later are omitted. This embodiment is different from the second embodiment in that the transparent electrode 5 on the substrate on the color filter side is formed.
A projection 64 was provided at a position corresponding to the center of the pixel 7. As the material of the projection 64, PIQ-6200 manufactured by Hitachi Chemical Co., Ltd., which is a polyimide-based organic compound, was used. Hereinafter, this material is referred to as PIQ for convenience. PIQ which is the material of the projection
Was applied by a spin coating method. The film thickness was 1 micron. Then, 90 ° C for 3 minutes, 180 ° C for 3 minutes, 3
Drying and baking were performed stepwise at 50 ° C. for 2 minutes. Further, the pattern of the protrusions was exposed by a photo process, and regions other than the protrusions were removed by wet etching. Since isotropic etching is performed by wet etching,
A protrusion having a tapered shape as shown in FIG. 12 can be formed.

Since the region where the protrusion 64 is located is a region where the voltage applied between the substrate 41 and the substrate 52 is locally small, each region in the multi-domain generated in the pixel by the driving method of the present invention is used. This has the effect of pinning the domain wall generated between the domains to the position of the protrusion 64. The direction in which the liquid crystal molecules fall is defined by the inclination of the side surface of the protrusion 64, and the directions in which the liquid crystal molecules fall on both sides of the protrusion 64 differ by 180 degrees. This also has the effect of pinning the domain wall to the position of the protrusion 64. By pinning the domain wall at a predetermined position, the size of each domain region in the multi-domain can be uniquely determined, so that the symmetry of the viewing angle can be more strictly controlled.

[0055]

According to the present invention, the rubbing step, which was conventionally required for defining the alignment direction of the liquid crystal, can be omitted, so that the transistor is damaged by static electricity and rubbing dust is generated. Such a problem can be prevented, and the effect on yield improvement and cost reduction is very large.

Alternatively, according to the present invention, since a plurality of domains can be formed in one pixel without using any special process, an inexpensive wide viewing angle liquid crystal display can be realized. It is.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of a pixel portion of a liquid crystal display element according to a first embodiment.

FIG. 2 is an enlarged top view of a pixel portion of the liquid crystal display element according to the first embodiment.

FIG. 3 is an explanatory diagram of liquid crystal alignment.

FIG. 4 is an explanatory diagram of liquid crystal alignment.

FIG. 5 is an image displayed on a pixel.

FIG. 6 is an applied voltage-luminance characteristic curve of the liquid crystal display device of the present invention.

FIG. 7 shows the relationship between the ratio of pixel pitch to cell gap, light use efficiency, and liquid crystal response speed.

FIG. 8 is an enlarged cross-sectional view of a pixel portion of a liquid crystal display element according to a second embodiment.

FIG. 9 is an enlarged top view of a pixel portion of a liquid crystal display element of Example 2.

FIG. 10 is an enlarged cross-sectional view of a pixel portion of a liquid crystal display element according to a third embodiment.

FIG. 11 is an enlarged top view of a pixel portion of a liquid crystal display element according to a third embodiment.

FIG. 12 is an enlarged cross-sectional view of a pixel portion of a liquid crystal display element of Example 4.

FIG. 13 is an enlarged top view of a pixel portion of a liquid crystal display element of Example 4.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reflective active matrix substrate, 2 ... Single crystal silicon substrate, 3, 43 ... Active element, 4, 46 ... Pixel electrode,
5 ... insulating layer, 8, 12, 51, 58 ... orientation control film, 9,
52: opposing glass substrate, 10, 42, 53: glass substrate, 11, 57: transparent electrode, 13, 59: liquid crystal layer, 14
... source diffusion layer, 15 ... source electrode, 16 ... drain diffusion layer, 17 ... drain electrode, 18 ... polysilicon gate, 19 ... storage capacitor, 25 ... electric field shielding electrode layer, 41 ... active matrix substrate, 44 ... drain line, 45: gate line, 48, 49, 50: insulating film, 54: black matrix, 55: color filter, 56: overcoat film, 62: electric field shielding layer, 63: slit, 64: protrusion.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-13166 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1337 G02F 1/133 505 G02F 1 / 1343 G09G 3/36

Claims (8)

(57) [Claims] 1. A pair of substrates, at least one of which is transparent at a predetermined interval and sandwiches a common electrode and a plurality of pixel electrodes juxtaposed in a row / column direction, and is provided between the pair of substrates. In a liquid crystal display element comprising a liquid crystal layer held at an interval and an alignment control film formed on a surface of the pair of substrates in contact with the liquid crystal layer, the alignment control film causes the liquid crystal to be substantially perpendicular to the substrate. A vertical alignment film for aligning, wherein a voltage is applied to each pixel so that a potential difference between adjacent pixels in a column or row direction is always equal to or higher than a threshold voltage of liquid crystal driving, and driving is performed. Liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the polarity of the liquid crystal driving voltage is inverted with respect to a common potential between adjacent pixels. 3. The switching device according to claim 1, wherein a plurality of switching transistors connected to each of the plurality of pixel electrodes, a plurality of signal lines for supplying an image signal to the switching transistors, and ON / OFF control. A plurality of scanning lines, and between a layer forming the plurality of signal lines and the plurality of scanning lines and a layer forming the pixel electrode, a common potential which is an intermediate potential of an image signal is supplied. A liquid crystal display device comprising layers. 4. The liquid crystal display device according to claim 1, wherein a ratio between an arrangement pitch of the plurality of pixels and a predetermined interval between the substrates is 30: 1 or less. 5. The liquid crystal display device according to claim 1, wherein a distance between adjacent pixel electrodes of the plurality of pixels is smaller than a predetermined distance between the substrates. 6. The liquid crystal display device according to claim 1, wherein a slit is provided in an electrode at a position corresponding to the center of the pixel on one of the substrates. 7. The liquid crystal display device according to claim 1, wherein a projection is provided on the electrode at a position corresponding to the center of the pixel on one of the substrates. 8. The liquid crystal display device according to claim 1, wherein the spacer for maintaining a predetermined distance between the substrates is a spacer formed by a photo-etching process.