JP2001083520A - Multi-domain type liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high transmittance and a wide viewing angle by forming a structure which becomes a domain division-forming factor only on one substrate and constructing tilt controlling and alignment dividing structure with a pixel electrode component and an insulation layer shape at the lower part of the pixel electrode. SOLUTION: Recessing inclined parts 8 are formed on an insulation layer 9. Respective pixel electrodes 7 are formed on the insulation layer 9 containing the recessed and inclined parts 8 and are electrically connected to the corresponding auxiliary capacitance electrodes 6 via the recessed and inclined parts 8. Division of liquid crystal alignment is induced on boundaries of inclined planes 8a, 12a of the recessed and inclined parts 8 and projected and inclined parts 12. Alignment of liquid crystal molecules 20 results in arrangements 15, 16 in which the long molecular axes are inclined with specified angles from the direction perpendicular to the glass substrate to the inclined directions of the inclined planes. Owing to the fact that the inclined directions of the inclined arrangements 15, 16 mutually coincide, the liquid crystal molecules 20 in the region surrounded by the inclined planes 8a and 12a incline toward the tilt direction 17 to form a domain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-domain type liquid crystal display device, and more particularly to a high definition type liquid crystal display device driven by an active device such as a thin film transistor.

[0002]

2. Description of the Related Art A display device using a liquid crystal display element has features such as light weight, thin shape, and low power consumption.
It is used in various fields such as OA equipment, information terminals, clocks, and televisions. In particular, thin film transistors (hereinafter TF)
A liquid crystal display element using T) is used for a display monitor that displays data including a lot of information, such as a portable television or a computer, due to its high responsiveness.

In recent years, as the amount of information has increased, there has been a demand for improvements in image definition and display speed. In order to improve the definition, a TFT array structure is miniaturized. On the other hand, in the liquid crystal layer that performs light switching, the operation speed per unit time is shortened with the miniaturization of pixels, so that the response speed of the liquid crystal material is required to be two to several tens times faster than the current mode. You.

As a liquid crystal mode satisfying these requirements, an OCB mode, a VAN mode, and a HAN mode using a nematic liquid crystal.
A system, a π-alignment system, an interface-stable ferroelectric liquid crystal (SSFLC) system using a smectic liquid crystal, and an antiferroelectric liquid crystal system are being studied. In particular, the VAN type alignment mode can provide a faster response speed than the conventional twisted nematic type (TN) mode, and the use of the vertical alignment process has conventionally raised concerns about the occurrence of defects such as electrostatic breakdown. This is a liquid crystal display mode that has recently attracted attention because the alignment process can be omitted.

In the VAN-type alignment mode, a multi-domain VAN liquid crystal mode for realizing a wide viewing angle has attracted attention because it is easy to design a compensation for a viewing angle.

[0006]

However, in the multi-domain VAN liquid crystal mode, it is difficult to secure the light transmittance due to the occurrence of domain boundaries and the like induced by the domain division, and it is difficult to ensure the light transmission on the opposing surface of the active element. There is a problem that the electrode resistance value is easily increased.

The present invention has been made in view of the above points, and an object of the present invention is to provide a multi-domain liquid crystal display element in which a structure serving as a domain division forming element is formed only on one surface of a liquid crystal display element substrate. In addition, the tilt control and the orientation division structure are configured by the components of the pixel electrode and the shape of the insulating layer below the pixel electrode, so that the light transmittance and the wide viewing angle are independent of the alignment accuracy with the counter substrate. It is to provide a liquid crystal display element which can ensure the following.

[0008]

In order to achieve the above object, a liquid crystal display device according to the present invention comprises a pair of substrates having a transparent electrode structure, a liquid crystal material sandwiched between these transparent substrates, A tilt control unit formed only on the substrate to control the tilt direction of the liquid crystal molecules.

Further, according to the liquid crystal display device of the present invention, the tilt control section includes the uneven insulating layer which is formed below the pixel electrode and determines the tilt direction of the liquid crystal molecules in the pixel electrode and performs orientation division. Have. Also, the tilt control unit
In the peripheral portion of the pixel electrode, an insulating layer formed below the pixel electrode and an insulating layer formed below another adjacent pixel electrode overlap with each other with a predetermined width, or a convex inclined portion, It has a convex inclined portion formed by a laminated structure with wiring.

According to the liquid crystal display device having the above structure, the tilt direction of liquid crystal molecules can be controlled stably, and a high light transmittance and a wide viewing angle can be realized.

An example of the one substrate is an array substrate on which active elements such as TFTs are formed. TFT
Is a semiconductor layer of a-Si, p-Si, ITO, etc., and A
By superimposing a metal layer such as l, Mo, Cr, Cu, Ta, or the like, the device is configured as an element that operates electrically. In particular, in the case of a COA (color filter-on-array) structure in which a color filter for color display is formed on an array substrate, unlike a method in which a color filter is formed on a counter substrate, alignment between transparent substrates becomes easy, Manufacturing efficiency can be improved.

As an insulating layer formed under the pixel electrode,
An inorganic layer typified by a metal oxide film such as SiOx, SiNx, Al ₂ O ₃ or an organic layer typified by polyimide, acrylic, epoxy or the like is used. Etching process)
Other materials may be used as long as they are transparent materials that can be processed by the above method. In particular, a resist material or a photosensitive acrylic resin in which the insulating material itself exhibits photosensitivity is suitable for the insulating layer of the present invention since it can be patterned into a predetermined shape by performing mask exposure.

Further, the insulating layer is required to have a height and a tilt that are sufficient to induce a specific tilt in the alignment of liquid crystal molecules. The present inventors have experimentally examined the shape parameters of the insulating layer and found a dimension at which stable operation as a liquid crystal display element can be obtained.

First, when the height of the insulating layer is set so that the thickness of the layer constituting one inclined surface is in the range of 1.0 to 1.5 μm, the electro-optical characteristics of the liquid crystal molecules are reduced. Found to be stable. Also, regarding the inclination of the insulating layer,
It has been found that the tilt direction of the liquid crystal molecules can be controlled stably when the maximum inclination angle is formed as an inclined surface of 30 to 89 ° or when it is formed as a curved surface such as a cylindrical outer peripheral surface.

In the case where the above-mentioned slope is formed by the insulating layer, the shape of the slope can be controlled by using a taper etching method by controlling an etching process in the inorganic or organic insulating layer having no photosensitivity. is there. On the other hand, in the case of an organic insulating layer exhibiting photosensitivity, after a taper is formed by exposure using a concentration gradient mask or a pattern having no slope is formed, a melt of the insulating layer is induced by a heating step, and a predetermined shape is formed by surface tension. Can be formed.

For example, a photosensitive acrylic resin or the like is a material that can easily form a slope of a cylindrical shape by controlling the temperature of a heating step after patterning, and has high process stability and is suitable for the insulating layer of the present invention. Material.

When a pigment that transmits and absorbs light of a specific wavelength is dispersed in an organic insulating layer and used as a color filter,
An insulating layer provided under the pixel electrode, a color filter layer,
In addition, the tilt control layer can be formed of one constituent material, the number of manufacturing steps and materials can be reduced, and a liquid crystal display element having excellent characteristics can be obtained at low manufacturing cost.

In general, in a liquid crystal display device, a color image can be displayed by forming a color filter layer such as RGB for each adjacent pixel in parallel. As described above, when the color filter layer is formed for each adjacent pixel, one inclined structure required for tilt control of liquid crystal molecules can be formed by overlapping the insulating layers.

Further, by forming the insulating layers provided below the adjacent pixel electrodes at regular intervals,
An inclined structure of the insulating layer can be obtained. That is, a convex inclined structure can be obtained by overlapping the insulating layers, or a concave inclined structure can be obtained by providing a gap between the insulating layers. The convex inclined structure and the concave inclined structure are selected according to the design of how to control the tilt alignment division in the pixel, but can be easily changed by changing the mask dimension when patterning the insulating layer. It is selectable and it is a simple method in production.

As described above, a predetermined orientation division structure is formed for each pixel by the inclined structure of the insulating layer itself provided below the pixel electrode and the inclined structure formed by the adjacent insulating layers. A liquid crystal display device having transmittance and a wide viewing angle can be realized.

In particular, when tilt control is performed by the concave inclined structure of the insulating layer formed below the pixel electrode and the convex inclined structure of the peripheral portion of the pixel formed by overlapping the adjacent insulating layers, the pixel electrode is charged. By providing the wiring for supplying the superimposed on the concave inclined structure, an inclined structure region other than the originally required tilt control inclined structure does not occur,
Light utilization efficiency in the pixel portion is improved, and bright display characteristics can be maintained.

The wiring for supplying electric charges to the pixel electrode includes:
A wiring from a source electrode for supplying electric charge from the TFT to the pixel electrode and an auxiliary capacitance electrode for assisting electric charge supply to the pixel electrode may be used. Generally, these wirings are connected to the pixel electrode via a recess called a contact hole or a via formed in an insulating layer provided below the pixel electrode. The recessed inclined structure formed in a predetermined pattern can be used as a contact hole. In this case, conventionally, several μm to 10 μm
It is possible to improve the contact characteristics of a contact hole which is formed by the minute dents and has low reliability of electrical connection.

On the other hand, an independent pixel electrode structure for generating an electric field between the concave inclined structure of the pixel portion and the flat portion is TF
A film formed for signal wiring in the T array forming process
A predetermined pattern of independent electrodes is formed in advance under the pixel electrodes using a thin film or a MoT thin film, and an insulating layer for forming a concavo-convex structure is formed thereon. By removing the located insulating layer, an electric field can be formed between the ITO film formed on the insulating layer and the independent electrode having the predetermined pattern.
The electric field induced by the independent electrode is in a signal state in which a potential difference always higher than the liquid crystal layer driving potential with respect to the pixel potential on the TFT array substrate is formed, and the electric field is applied from the pixel flat portion electrode end to the concave structure electrode end. Are formed, and the tilt direction of the liquid crystal molecules can be stably controlled.

Further, as the insulating layer formed on one of the substrates, an insulating layer provided below the pixel electrode and constituting an inclined structure, and a SiO 2 film formed so as to cover the entire area of the pixel electrode are provided.
An x film or an acrylic insulating organic film is used. As a material of the insulating layer, a material having a relatively low dielectric constant is preferable, though it depends on the dielectric constant of the liquid crystal material to be used.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a multi-domain liquid crystal display device and a pixel structure thereof according to an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the liquid crystal display element includes an array substrate 1 and a counter substrate 2 which are arranged to face each other with a predetermined gap, and a liquid crystal layer 32 sandwiched between these substrates.

The array substrate 1 includes a glass substrate as a transparent insulating substrate. On the glass substrate, a large number of signal lines 4 and scanning lines 5 extending in a matrix, and these signal lines 4 and scanning lines 5 are arranged. TFT3 connected to each intersection of
And an auxiliary capacitance electrode 6 serving as a connection electrode. A pixel electrode 7 is provided in each region surrounded by the signal lines 4 and the scanning lines 5, and is electrically connected to the corresponding TFT 3. The pixel electrode 7 and the auxiliary capacitance electrode 6
The insulating layer 9 is formed between the two.

On the other hand, the opposite substrate 2 includes a glass substrate as a transparent insulating substrate, and a transparent conductive film 1 made of ITO (indium-tin-oxide) is provided on the glass substrate.
0 is formed over almost the entire surface. At the interfaces of the array substrate 1 and the opposing substrate 2 that are in direct contact with the liquid crystal layer 32, alignment films 13 and 14 that give the liquid crystal molecules 20 alignment in a direction perpendicular to the substrate are formed. As a result, the liquid crystal molecules 20 are oriented such that their major axes are oriented in a direction perpendicular to the interface of the substrate.

In each pixel region, a concave inclined portion 8 is formed in the insulating layer 9. This concave inclined portion 8
It has a pair of curved inclined surfaces 8a facing each other with a gap, and extends in each pixel region almost in parallel with the signal lines 4.
Each pixel electrode 7 is formed on the insulating layer 9 including the concave inclined portion 8, and is electrically connected to the corresponding auxiliary capacitance electrode 6 via the concave inclined portion.

Further, the insulating layer 9 in the peripheral portion of each pixel electrode 7 is formed so as to overlap with the insulating layer 9 in another adjacent pixel region by a predetermined width, and the overlapping portion constitutes a convex inclined portion 12. ing. The convex inclined portion 12 has an inclined surface 12 a protruding toward the counter substrate 2, extends substantially parallel to the signal line 4, and is located between the adjacent pixel electrodes 7.

The concave inclined portion 8 and the convex inclined portion 12
At the interface between the inclined surfaces 8a and 12a, the division of the liquid crystal alignment is induced, and the alignment of the liquid crystal molecules 20 is such that the major axis is inclined by a specific angle from the direction perpendicular to the glass substrate to the inclination direction of the inclined surface. 15 and 16. This inclined array 1
When the inclination directions of 5 and 16 coincide with each other, the liquid crystal molecules 20 in the region surrounded between the inclined surfaces 8a and 12a fall in the tilt direction 17 to form a domain. By forming a plurality of these domains in one pixel region, an effect of compensating for the anisotropy of the liquid crystal molecules 20 is generated, and a wide viewing angle can be realized.

Next, examples and comparative examples of the liquid crystal display device having the above-described basic configuration will be described together with a manufacturing method. Example 1 As shown in FIG. 2, first, wirings such as a signal line 4 and a scanning line 5, a TFT 3, and an auxiliary capacitance electrode 6 were formed on a glass substrate by a known method. A photosensitive resin is formed into a film having a thickness of 1.2 μm.
Perform pre-annealing for only 0 seconds.

Subsequently, the acrylic photosensitive resin film is exposed by a parallel exposure device using a mask corresponding to the pixel electrode one-to-one, and is further patterned by a development process.
Thereafter, post-annealing was performed at 230 ° C. for 1 hour, and the acrylic photosensitive resin film was subjected to a melt process and a hardening process, so that the concave slope portions 8 each having a slope 8 a were located at the pixel formation region. The first insulating layer 9a is formed.

Next, a second insulating layer 9b and a third insulating film 9c located between the adjacent first insulating layers 9a are formed by the same steps as described above. In this case, each of the second insulating layer 9b and the third insulating film 9c has a concave inclined portion 8 having an inclined surface 8a, and each end overlaps with another insulating layer adjacent outside the pixel region, The convex inclined portion 12 is formed.

Subsequently, the first and second sputter devices are used.
And a thickness of 1000Å on the third insulating layers 9a, 9b, 9c.
Is formed, and at the same time, conduction is made to the auxiliary capacitance electrode 6 via the concave inclined portion 8. Then, a known photolithography process is performed on the ITO film to form the pixel electrode 7, and then a 700-mm-thick polyimide film for vertical alignment is formed as an alignment film 13 on the entire surface, thereby forming the array substrate 1. Further, on the wiring that deviates from the pixel region on the alignment film 13 of the array substrate 1, 1
4μ height using acrylic photosensitive resin
m, a spacer 22 having a diameter of 20 μm was formed.

On the other hand, on the glass substrate of the opposing substrate 2, a common electrode 10 made of ITO and having a thickness of 1000.degree. Is formed as a transparent conductive film.
To form a vertical alignment polyimide film having a thickness of 700 °.

Subsequently, in the sealing area on the periphery of the opposing substrate 2,
An epoxy-based thermosetting resin is applied as a sealing material by a dispenser. Then, the array substrate 1 and the opposing substrate 2 are bonded together via a sealing material so that the alignment films 13 and 14 face each other.
The sealing material is thermally cured by heat treatment for a time.
Thus, a cell 30 for injecting liquid crystal molecules is formed.
Thereafter, a liquid crystal material exhibiting negative dielectric anisotropy was injected into the cell 30 and sealed to form a vertically aligned liquid crystal layer 32. Through the above steps, a liquid crystal display element is completed.

FIG. 3 shows the liquid crystal molecule alignment division state in each pixel in the operation state of the liquid crystal display element configured as described above. The concave inclined portion 8 and the convex inclined portion 12 are shown.
Thereby, the domain structure divided stably can be confirmed.

Comparative Example 1 FIG. 4 shows Comparative Example 1 corresponding to Example 1 of the present invention shown in FIG. When manufacturing the liquid crystal display element according to Comparative Example 1, first, wirings such as the signal lines 44 and the scanning lines 45 and the TFT 4 are formed on a glass substrate by a known method.
3, and after forming the auxiliary capacitance electrode 46, an acrylic photosensitive resin is formed in a thickness of 1.2 μm on the auxiliary capacitance electrode 46 and pre-annealed at 90 ° C. for 120 seconds.

Subsequently, the acrylic photosensitive resin film is exposed to light using a mask corresponding to the pixel electrodes one-to-one by a parallel exposure device, and is further patterned by a development process.
Thereafter, post-annealing is performed at 230 ° C. for 1 hour, and the acrylic photosensitive resin film is subjected to a melt treatment and a curing treatment, thereby forming an insulating layer 49 having a contact hole 48 on the entire surface.

Subsequently, the insulating layer 49 is formed by a sputtering device.
An ITO film having a thickness of 1000 成膜 is formed thereon, and at the same time, conduction is made to the auxiliary capacitance electrode 46 via the contact hole 48. Then, a known photolithography process is performed on the ITO film to form a pixel electrode 47, and then a 700-mm-thick polyimide film for vertical alignment is formed as an alignment film 53 on the entire surface, whereby the array substrate 1 is formed.

On the other hand, on the glass substrate of the opposite substrate 2, a common electrode 50 made of ITO and having a thickness of 1000.degree. Is formed as a transparent conductive film.
To form a vertical alignment polyimide film having a thickness of 700 °.

Subsequently, an epoxy-based thermosetting resin is applied as a sealing material to the sealing region of the counter substrate 2 by a dispenser. Further, in order to maintain a constant cell gap, resin spacers 56 having a diameter of 4 μm are sprayed on the array substrate 1 so as to be about 30 per 1 mm ² .

Then, the array substrate 1 and the opposing substrate 2 are bonded together with a sealing material so that the alignment films 53 and 54 face each other, and heat-treated at 160 ° C. for 2 hours while applying a predetermined load to form a seal. The material is heat cured. Thus, a cell 30 for injecting liquid crystal molecules is formed. Thereafter, a liquid crystal material exhibiting negative dielectric anisotropy was injected into the cell 30 and sealed to form a vertically aligned liquid crystal layer 32. Through the above steps, a liquid crystal display element is completed.

As shown in FIG. 5, in the operation state of the liquid crystal display device configured as described above, the liquid crystal molecule alignment division state in each pixel is caused by the generation of a schlieren structure due to the leakage magnetic field around the contact hole 48 and the pixel. However, it was confirmed that the alignment state was unstable.

Embodiment 2 As shown in FIG. 6, the liquid crystal display device according to Embodiment 2 is manufactured by the same process as the liquid crystal display device according to Embodiment 1, and has the same configuration. However, when the first, second, and third insulating layers 9a, 9b, and 9c of the array substrate 1 are formed, red, blue, and green pigments are dispersed and used in an acrylic photosensitive resin material, respectively. The color filter insulating layers 9R, 9B, 9G having a thickness of 3 μm are formed.
The common electrode 1 is provided on the opposite substrate 2 as in the first embodiment.
Only 0 and the alignment film 14 are provided. In addition, the same parts as those in the first embodiment are denoted by the same reference numerals.

According to the second embodiment configured as described above,
A color liquid crystal display element having a domain structure stably divided by the concave inclined portions 8 and the convex inclined portions 12 is obtained.

Comparative Example 2 As shown in FIG. 7, the liquid crystal display element according to Comparative Example 2 is a colorized version of the liquid crystal display element according to Comparative Example 1 shown in FIG. 1 is manufactured by the same process. Further, in addition to the common electrode 50 and the alignment film 54, the opposing substrate 2 includes red, blue, and green color layers 60R, 60B, and 60G and a black stripe 6.
A color filter layer 60 having 0BK is provided.

Also in the liquid crystal display device thus configured, a schlieren structure is generated in each pixel, and an unstable liquid crystal molecule alignment state is obtained.

Third Embodiment FIGS. 8 to 10 show a liquid crystal display device according to a third embodiment of the present invention. When manufacturing this liquid crystal display element, first, a signal line 4, an independent electrode 37 in the same layer as the signal line, wirings such as a scanning line 5, a TFT 3, and an auxiliary capacitance electrode are formed on a glass substrate by a known method. After the formation of No. 6, an acrylic photosensitive resin is formed thereon with a thickness of 1.2 μm, and is pre-annealed at 90 ° C. for 120 seconds.

Subsequently, the acrylic photosensitive resin film is exposed by a parallel exposure apparatus using a mask corresponding to the pixel electrodes one-to-one, and is patterned by a development process.
Thereafter, post-annealing is performed at 230 ° C. for 1 hour, and the acrylic photosensitive resin film is melt-processed and hardened to be located at the pixel formation region, respectively, and at the contact hole 35 and the independent electrode 37. And a concave portion 38 having an inclined surface 8a.
a is formed.

Next, a second insulating layer 9b and a third insulating film 9c located between the adjacent first insulating layers 9a are formed by the same steps as described above. In this case, each of the second insulating layer 9b and the third insulating film 9c is formed with a contact hole 35,
And a concave portion 38 having an inclined surface 8 a, and each end overlaps with another insulating layer adjacent outside the pixel region to form a convex inclined portion 12.

Subsequently, the first and second sputter devices are used.
And a thickness of 1000Å on the third insulating layers 9a, 9b, 9c.
Is formed, and a photolithography process is performed to form a pixel electrode 7.
O is removed to form a substantially rectangular electrode removing portion 39.
Thereafter, a polyimide film for vertical alignment having a thickness of 700 ° is formed as an alignment film 13 on the entire surface. Further, a spacer 22 having a height of 4 μm and a diameter of 20 μm using acrylic photosensitive resin is provided on the wirings deviating from the pixel region on the alignment film 13 of the array substrate 1 at a ratio of one pixel electrode to 10 pixel electrodes. Was formed.

On the other hand, on the glass substrate of the opposite substrate 2, a common electrode 10 made of ITO and having a thickness of 1000.degree. Is formed as a transparent conductive film.
To form a vertical alignment polyimide film having a thickness of 700 °.

Subsequently, an epoxy-based thermosetting resin is applied as a sealing material to the sealing region of the counter substrate 2 by a dispenser. Then, the array substrate 1 and the opposing substrate 2 are bonded together via a sealing material so that the alignment films 13 and 14 face each other, and heat-treated at 160 ° C. for 2 hours while applying a predetermined load, so that the sealing material is heated. To cure. Thus, a cell 30 for injecting liquid crystal molecules is formed. Thereafter, a liquid crystal material exhibiting negative dielectric anisotropy was injected into the cell 30 and sealed to form a vertically aligned liquid crystal layer 32. Through the above steps, a liquid crystal display element is completed.

Fourth Embodiment FIG. 11 shows a liquid crystal display device according to a fourth embodiment of the present invention. In the case of manufacturing this liquid crystal display element, first, wirings such as the signal line 4 and the scanning line 5, the TFT 3, and the auxiliary capacitance electrode 6 are formed on a glass substrate by a known method. An acrylic photosensitive resin is formed into a film having a thickness of 1.2 μm, and is pre-annealed at 90 ° C. for 120 seconds.

Subsequently, the acrylic photosensitive resin film is exposed by a parallel exposure device using a mask corresponding to the pixel electrodes one-to-one, and is further patterned by a development process.
Thereafter, post-annealing is performed at 230 ° C. for 1 hour, and the acrylic photosensitive resin film is subjected to a melt treatment and a curing treatment, so that the first insulating layer 9 a having the contact hole 35 and being located in the pixel formation region is formed. Form.

The second insulating layer 9b having the contact hole 35 and the third
An insulating layer 9c is formed on both sides of the first insulating layer 9a,
The convex inclined portion 12 is formed by overlapping the first insulating layer 9a by a predetermined width at the peripheral portion of the pixel.

Subsequently, the first and second sputtering devices are used.
And a thickness of 1000Å on the third insulating layers 9a, 9b, 9c.
Is formed, and at the same time, conduction is made to the auxiliary capacitance electrode 6 through the contact hole 35. Then, a known photolithography process is performed on the ITO film to form the pixel electrode 7.

Thereafter, the pixel electrode 7 is
And a 1500 ° thick SiOx41 film is formed thereon.
Then, the SiOx film 41 is removed in a slit shape at a position facing the central portion of each pixel electrode 7 by an etching process, thereby forming an electric field concentration region 40 for tilt control.

Subsequently, a polyimide film for vertical alignment having a thickness of 700 ° is formed as an alignment film 13 on the entire surface. Further, a spacer 22 having a height of 4 μm and a diameter of 20 μm using acrylic photosensitive resin is provided on the wirings deviating from the pixel region on the alignment film 13 of the array substrate 1 at a ratio of one pixel electrode to 10 pixel electrodes. Was formed.

On the other hand, on the glass substrate of the opposite substrate 2, a common electrode 10 made of ITO and having a thickness of 1000 ° is formed as a transparent conductive film, and SiOx is superposed on the common electrode.
An 800-mm thick insulating layer 42 of a film was formed by a sputter deposition apparatus, and a 700-mm-thick polyimide film for vertical alignment was formed thereon as the alignment film 14.

Subsequently, an epoxy-based thermosetting resin is applied as a sealing material to the sealing region of the counter substrate 2 by a dispenser. Then, the array substrate 1 and the opposing substrate 2 are bonded together via a sealing material so that the alignment films 13 and 14 face each other, and heat-treated at 160 ° C. for 2 hours while applying a predetermined load, so that the sealing material is heated. To cure. Thus, a cell 30 for injecting liquid crystal molecules is formed. Thereafter, a liquid crystal material exhibiting negative dielectric anisotropy was injected into the cell 30 and sealed to form a vertically aligned liquid crystal layer 32. Through the above steps, a liquid crystal display element is completed.

FIG. 12 shows Embodiment 1 of the present invention described above.
2, and the display characteristics of the liquid crystal display elements according to Comparative Examples 1 and 2 are shown in comparison. In this figure, the transmittance shows a value corresponding to a liquid crystal display device having a pixel size of 10.4 inches and XGA.

As is apparent from this figure, in each of the liquid crystal display elements according to the first and second embodiments of the present invention, stable domain division can be obtained without generation of schlieren, and the factor of reduction in light transmittance. It is possible to provide a bright multi-domain vertical alignment display mode having a wide viewing angle characteristic and a high light transmittance with little misalignment of pixels.

In particular, it is possible to form an inclined structure for inducing alignment division without changing the conventional process of manufacturing a pixel-mounted TFT array, thereby minimizing the influence on manufacturing cost and manufacturing efficiency. As a result, productivity can be improved. The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention.

[0066]

As described above in detail, according to the present invention, a structure serving as a domain division forming element is formed only on one substrate, and a component of the pixel electrode and an insulating layer below the pixel electrode are formed. By configuring the tilt control and the orientation division structure depending on the shape, a liquid crystal display element capable of securing a high light transmittance and a wide viewing angle without depending on the alignment accuracy with the counter substrate can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a basic configuration of a liquid crystal display device according to the present invention.

FIG. 2 is a perspective view schematically showing a liquid crystal display device according to Embodiment 1 of the present invention.

FIG. 3 is a view showing a pixel light transmission state when the liquid crystal display element according to the first embodiment is driven.

FIG. 4 is a perspective view schematically showing a liquid crystal display device according to Comparative Example 1.

FIG. 5 is a diagram showing a pixel light transmission state when the liquid crystal display element according to Comparative Example 1 is driven.

FIG. 6 is a perspective view schematically showing a liquid crystal display element according to Embodiment 2 of the present invention.

FIG. 7 is a perspective view schematically showing a liquid crystal display element according to Comparative Example 2.

FIG. 8 is a perspective view schematically showing a liquid crystal display element according to Embodiment 3 of the present invention.

FIG. 9 is a plan view schematically showing one pixel unit in the third embodiment.

FIG. 10 is a sectional view taken along the line AA in FIG. 9;

FIG. 11 is a perspective view schematically showing a liquid crystal display element according to Embodiment 4 of the present invention.

FIG. 12 is a diagram showing a comparison between display characteristics of Examples 1 and 2 and Comparative Examples 1 and 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Array board | substrate 2 ... Counter substrate 3 ... TFT 4 ... Signal line 5 ... Scanning line 6 ... Storage capacitor electrode 7 ... Pixel electrode 8 ... Concave slope part 9 ... Insulating layer 9a ... First insulating layer 9b ... Second insulating layer 9c ... third insulating layer 10 ... common electrode 12 ... convex inclined part 20 ... liquid crystal molecules 35 ... contact hole 37 ... independent electrode 38 ... concave part 39 ... electrode removal part 40 ... electric field concentration area

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroyuki Nagata 1-9-2 Hara-cho, Fukaya-shi, Saitama F-term in Fukaya Plant, Toshiba Corporation (reference) 2H090 HA04 HB03X HB04X HB06X HB08Y HB13Y JB02 LA01 LA03 LA04 LA15 MA01 MA08 MA10 MA15 2H092 GA05 GA29 HA04 HA06 JA24 JB56 JB64 KA04 KA05 KB04 MA05 MA16 NA01 NA27 NA29 PA01 PA08

Claims (10)

[Claims] A liquid crystal layer sandwiched between a pair of substrates; an electrode formed on one or both of the substrates for driving liquid crystal molecules constituting the liquid crystal layer; A multi-domain type liquid crystal display device, comprising: a tilt control unit that controls a tilt direction of liquid crystal molecule alignment. 2. The method according to claim 1, wherein the one substrate includes an insulating substrate and a plurality of pixel electrodes provided on the insulating substrate, and the tilt control unit is formed below the pixel electrode on the insulating substrate. 2. The multi-domain liquid crystal display device according to claim 1, further comprising an insulating layer having an uneven shape. 3. The tilt control section is formed by superposing insulating layers provided below adjacent pixel electrodes with a predetermined width on a peripheral portion of the pixel electrode to determine a tilt direction of the liquid crystal molecules. 3. The multi-domain liquid crystal display device according to claim 2, further comprising a convex inclined portion that is divided by orientation. 4. The one substrate has a wiring provided on the insulating substrate in a peripheral portion of the pixel electrode, and the tilt control section is formed on the wiring. The multi-domain liquid crystal display device according to claim 2. 5. The one substrate includes a connection electrode formed on the insulating substrate below the pixel electrode and supplying a charge to the pixel electrode. The insulating layer includes the pixel electrode and the connection electrode. 3. The multi-domain liquid crystal display device according to claim 2, further comprising a contact hole for electrical connection. 6. The one substrate includes an insulating substrate and a plurality of pixel electrodes provided on the insulating substrate, and the tilt controller is formed below the pixel electrode on the insulating substrate. An insulating layer which is formed and has a concave portion,
2. The multi-domain type according to claim 1, further comprising: an independent electrode disposed to face the concave portion, wherein each of the pixel electrodes includes an electrode removing portion in a region corresponding to the concave portion. 3. Liquid crystal display element. 7. The tilt control section is formed by superposing insulating layers provided below adjacent pixel electrodes with a predetermined width on a peripheral portion of the pixel electrode to determine a tilt direction of the liquid crystal molecules. 7. The multi-domain liquid crystal display device according to claim 6, further comprising a convex inclined portion divided by orientation. 8. The one substrate has a wiring provided on the insulating substrate at a peripheral portion of the pixel electrode, and the convex inclined portion is formed on the wiring. The multi-domain liquid crystal display device according to claim 6. 9. The one substrate includes an insulating substrate, a plurality of pixel electrodes provided on the insulating substrate, and a wiring provided on the insulating substrate at a periphery of the pixel electrode. The tilt control unit includes an insulating layer formed below the pixel electrode on the insulating substrate, and, at a peripheral portion of the pixel electrode, the insulating layers provided below the adjacent pixel electrodes. A convex inclined portion which is formed so as to be overlapped with each other with a predetermined width and determines the tilt direction of the liquid crystal molecules and is orientation-divided; and the one substrate has another insulating layer formed so as to be overlapped on the pixel electrode, 2. The multi-domain liquid crystal display device according to claim 1, further comprising a plurality of slit-shaped electric field concentrating portions formed on the other insulating layer and exposing a part of each pixel electrode. . 10. The multi-domain liquid crystal display device according to claim 2, wherein the insulating layer provided below the pixel electrode is formed by a color filter layer.