JP2000147517A - Liquid crystal display device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain uniform cell thickness, to decrease the number of production processes and to obtain a display with a large angle of visual field and high quality by using spacer beads partly embedded and fixed in a polymer wall to regulate the distance between substrates. SOLUTION: A color filter having a color resin layer 3 and a BM layer 2 to shade the space among the color patterns from light is formed on a glass substrate 1a. An overcoating layer 4 and a transparent electrode 5 are formed thereon. Further, a polymer wall 6 is formed to surround the pixels, and spacer beads 7 to regulate the cell thickness are partly embedded and fixed in the polymer wall 6. Since formation of columnar projections or increase in the height of the polymer wall 6 are not required, irregular thickness of the cell due to irregular coating of the photosensitive resin can be prevented. The polymer wall 6 is preferably formed to have a inclined part in the cross section with the taper angle between 5 deg. and 45 deg. to one substrate.

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 used as a display of, for example, a personal computer, a word processor, an amusement device, a television device, and the like, and a method of manufacturing the same. The present invention relates to a liquid crystal display device in which liquid crystal molecules are axially symmetrically aligned when a voltage is applied, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a display device using an electro-optic effect, a TN (twisted nematic) type or STN (super twisted nematic) type liquid crystal display device using a nematic liquid crystal has been known. However, these liquid crystal display devices have a problem that the viewing angle is narrow, and therefore, technical development for widening the viewing angle is being vigorously conducted.

Until now, as one of the techniques for widening the viewing angle of a liquid crystal display device, Japanese Patent Application Laid-Open Nos. Hei 6-301015 and Hei 7-120728 disclose a technique in which a liquid crystal region divided by polymer walls is used. A so-called ASM (Axially Symmetrical) for aligning liquid crystal molecules in an axially symmetric manner.
There is disclosed a liquid crystal display device of an aligned Microcell mode. Typically, a liquid crystal region substantially surrounded by polymer walls is formed for each pixel.

In this ASM mode liquid crystal display device, a polymer wall substantially surrounding the liquid crystal region is formed on the surface of at least one of the substrates on the liquid crystal layer side.
When a voltage is applied, the liquid crystal molecules are aligned in an axially symmetric manner for each liquid crystal region, and the viewing angle dependency can be eliminated.

The principle of operation of the liquid crystal display will be described with reference to FIG. FIGS. 6A and 6B are diagrams showing a state when no voltage is applied, and FIGS.
FIG. 6D is a diagram showing a state when a voltage is applied, and FIG.
6 (b) is a cross-sectional view, and FIGS. 6 (c) and 6 (d) are views showing the results of observing the upper surface with a crossed Nicol state polarizing microscope.

This liquid crystal display device comprises a pair of substrates 14 and 1
8, a liquid crystal layer 16 made of liquid crystal molecules 11 having a negative dielectric anisotropy is sandwiched. Transparent electrodes 19 and 10 are provided on the surfaces of the substrates 14 and 18 that are in contact with the liquid crystal layer 16, respectively.
Are formed, and the vertical alignment films 22 and 21 are formed thereon. On the surface of one substrate 18 on the liquid crystal layer 16 side,
An inclined polymer wall 17 is formed, and a columnar projection 20 is selectively formed thereon. The liquid crystal region 15 is defined by the polymer wall 17 having the inclination. As shown in FIG. 6C described later, the liquid crystal molecules 11 in the liquid crystal region 15 are axially symmetric with respect to the axially symmetric alignment center axis 12. Orient.

When no voltage is applied, as shown in FIG. 6A, the liquid crystal molecules 11 are aligned in a direction substantially perpendicular to the substrate by the alignment control force of the vertical alignment films 21 and 22. When the liquid crystal region 15 in this state is observed with a crossed Nicol state polarizing microscope, a dark field is exhibited (normal black mode) as shown in FIG. 6B.

When a voltage is applied to the liquid crystal layer, a force acts on the liquid crystal molecules 11 having negative dielectric anisotropy to orient the major axis of the liquid crystal molecules 11 perpendicular to the direction of the electric field.
As shown in (c), the liquid crystal molecules 11 tilt from a direction perpendicular to the substrate (halftone display state). The liquid crystal region 15 in this state
When observed with a polarizing microscope in a crossed Nicols state, FIG.
As shown in (d), an extinction pattern is observed in the direction along the polarization axis.

As described above, in the liquid crystal display device of the present invention, when no voltage is applied, the liquid crystal molecules 11 are oriented in the direction perpendicular to the substrate to display black, and when a voltage is applied, the liquid crystal molecules 11 are aligned with the central axis of each liquid crystal region 15. It operates in a normally black mode in which a white display is formed in an axially symmetric orientation state with respect to the center 12.
Note that, in this specification, the axially symmetric orientation state refers to, for example, a state of being spirally oriented as shown in FIG. 7, and other states include concentric circles, radial states, and the like. The central axis of this axisymmetric orientation generally coincides substantially with the normal direction of the substrate. FIG. 7 is a perspective view schematically illustrating the orientation state of liquid crystal molecules in the liquid crystal region by modeling the liquid crystal region. FIG. 7A shows the liquid crystal region 1 defined by the polymer wall 17.
7B shows an alignment state of liquid crystal molecules in the liquid crystal region 15, 15T in FIG. 7C shows an alignment state of an upper layer portion in the region 15, and 15M shows an intermediate state in the region 15. 15B shows the orientation state of the layer, and 15B shows the orientation state of the lower layer portion.

With such an ASM mode axially symmetric alignment state, the viewing angle characteristics can be improved as follows.

That is, in the case of the TN mode, FIG.
As shown in FIGS. 8D to 8F, the orientation direction of the liquid crystal molecules is one direction, and when the liquid crystal display device is viewed from both directions A and B in the halftone state shown in FIG. It looked good, but on the other hand it was hard to see.

On the other hand, in the case of the axially symmetric alignment in which the alignment directions of the liquid crystal molecules are two or more, FIGS. 8 (a) to 8 (c)
As shown in FIG. 8B, the apparent refractive indices of the liquid crystal molecules when viewed from both the A and B directions are averaged, and the transmittance of light from both the A and B directions becomes equal. The viewing angle characteristics are improved even in the halftone state.

As described above, in the ASM mode liquid crystal display device, since the liquid crystal molecules are axially symmetrically aligned, the change in contrast is small and the wide field of view is obtained even when the observer observes the liquid crystal display device from any direction. Angular characteristics can be realized.

The ASM mode liquid crystal display device disclosed in the above-mentioned publication is manufactured by subjecting a mixture of a polymerizable material and a liquid crystal material to polymerization-induced phase separation.

A method of manufacturing a conventional ASM mode liquid crystal display device will be described below with reference to FIG.

First, as shown in FIG. 9A, a substrate (color filter substrate) having a color filter and electrodes formed on one surface of a glass substrate 308 is prepared. Note that FIG.
Here, for simplicity, the electrodes and color filters formed on the upper surface of the glass substrate 308 are not shown.

Next, as shown in FIG. 9B, a polymer wall 317 for orienting liquid crystal molecules axially symmetrically is formed on the surface of the glass substrate 308 on which the electrodes and the color filters are formed.
To form First, after spin-coating a photosensitive resin material, it is exposed to light through a photomask having a predetermined pattern and developed, so that, for example, a lattice-shaped polymer wall 3 is formed.
17 is formed. The photosensitive resin material may be a negative type or a positive type. Alternatively, although a step of separately forming a resist film is increased, the resist film may be formed using a resin material having no photosensitivity.

Subsequently, as shown in FIG. 9C, columnar projections 320 are discretely formed on the top of the polymer wall 317 by patterning. The columnar projections 320 also have the polymer wall 317.
Similarly to the above, it is formed by exposing and developing a photosensitive resin material.

Thereafter, as shown in FIG. 9D, the surface of the glass substrate on which the polymer walls 317 and the columnar projections 320 are formed is covered with a vertical alignment film 321 such as polyimide.

On the other hand, as shown in FIGS. 9E and 9F, the opposite glass substrate 302 on which the electrodes are formed is also covered with the vertical alignment film 321.

Next, as shown in FIG. 9 (g), the two substrates obtained are bonded together with the surface on which the electrodes are formed facing inward, to produce a liquid crystal cell. At this time, the distance between the two substrates (cell gap: the thickness of the liquid crystal layer) is defined by the sum of the heights of the polymer wall 317 and the columnar projection 320.

Subsequently, as shown in FIG. 9H, a liquid crystal material is injected into the gap of the obtained liquid crystal cell by a vacuum injection method or the like.

Finally, as shown in FIG. 9 (i), the liquid crystal molecules in the liquid crystal region 316 are axially symmetrically controlled. For example, by applying a voltage between a pair of electrodes disposed opposite to each other, the liquid crystal molecules in the liquid crystal region 316 divided by the polymer wall 317 are centered on an axis perpendicular to both substrates indicated by a broken line 315. Symmetrically oriented.

In FIG. 9, the glass substrate 3 is shown for simplicity.
Although the electrodes and color filters formed on the top surface of the pixel 08 were not shown, as shown in FIG. 10, the red (R), green (G), and blue (B) colored resin layers corresponding to the respective picture elements. 31
1 and a BM for shielding the gap between the colored patterns
A color filter having a (black matrix) layer 312 is provided. On top of that, overcoat layer 3
13, a transparent electrode (signal electrode) 314 made of indium tin oxide (ITO) is formed.

The overcoat layer 313 is provided to improve the smoothness so that no step is formed at the time of forming the ITO film and to protect the resin surface so that the etchant does not corrode the colored resin layer during the ITO etching. About 0.5μm ~ 2 by acrylic resin or epoxy resin
μm.

As the BM layer 312, generally, a metal film having a thickness of about 100 nm to 150 nm is used, but recently, a material other than metal is used. For example, carbon fine particles are dispersed in an acrylic photosensitive resin. A photoresist type is also used. As the colored resin layer 311, a material obtained by coloring a resin material with a dye or a pigment is used, and its film thickness is generally about 1 μm to 3 μm.

As a method of forming a color filter, a method of patterning a photosensitive colored resin layer formed on a substrate by using a photolithography technique is used. For example, using a photosensitive resin material of each color of red (R), green (G), and blue (B), forming, exposing, and developing a photosensitive colored resin layer (each three times), , G, B colored layer resin layer 311 can be formed. Examples of the method of forming the photosensitive colored resin layer include a method of applying a liquid photosensitive colored resin material diluted with a solvent by a spin coating method, a method of transferring a dry colored photosensitive colored resin material, and the like. Can be

Using the color filter substrate thus formed, an AS having a wide viewing angle characteristic as described above is used.
An M-mode liquid crystal display device can be manufactured.

[0029]

However, when the above-described ASM mode is applied to a liquid crystal display device, there are the following problems.

Since the cell thickness is determined using columnar projections formed by applying a photosensitive resin material to a substrate and patterning the same by a photolithography method, variations in film thickness when the photosensitive resin material is applied are displayed. This is a major cause of unevenness. Further, since it is necessary to separately form the columnar convex portions, the number of manufacturing steps increases.

Further, in order to increase the definition of the liquid crystal display device and to improve the brightness of the display, it is desired to make the width of the polymer wall for axially symmetrically aligning the liquid crystal molecules in the ASM mode as small and small as possible. However, in this case, it is necessary to relatively increase the height of the columnar protrusion for defining the cell thickness, and the influence of the film thickness variation at the time of forming the columnar protrusion becomes larger. In addition, it becomes difficult to form the columnar projection so that the bottom does not protrude from the polymer wall.

The present invention has been made to solve such problems of the prior art, and can make the cell thickness of the liquid crystal display device uniform and reduce the number of manufacturing steps. An object of the present invention is to provide a liquid crystal display device capable of obtaining high-quality display and a method for manufacturing the same.

[0033]

According to the liquid crystal display device of the present invention, a liquid crystal layer made of liquid crystal having negative dielectric anisotropy is sandwiched between a pair of substrates, and the liquid crystal layer is formed of the pair of substrates. It has a plurality of liquid crystal regions divided by a polymer wall provided on one of the substrates, and liquid crystal molecules in the plurality of liquid crystal regions are oriented substantially perpendicular to both substrates when no voltage is applied. A liquid crystal display device that is axially symmetrically oriented around an axis perpendicular to both substrates when voltage is applied, and is partially buried and fixed in the polymer wall by spacer beads.
The distance between the two substrates is defined, thereby achieving the above object.

It is preferable that the polymer wall has an inclined portion having a forward tapered cross section with respect to the one substrate.

It is preferable that the angle of the inclined portion is not less than 5 ° and not more than 45 ° with respect to the one substrate.

The polymer wall is preferably made of a photosensitive resin.

The polymer wall is preferably made of a negative photosensitive resin.

The polymer wall is preferably made of a transparent resin.

The width of the polymer wall is preferably at least twice the diameter of the spacer beads.

The spacer beads are preferably made of a transparent material.

According to the method of manufacturing a liquid crystal display device of the present invention, a liquid crystal layer made of liquid crystal having negative dielectric anisotropy is sandwiched between a pair of substrates, and the liquid crystal layer is formed on one of the pair of substrates. A plurality of liquid crystal regions divided by polymer walls provided on the substrate, and the liquid crystal molecules in the plurality of liquid crystal regions are oriented substantially perpendicular to both substrates when no voltage is applied, and Sometimes it is a method of manufacturing a liquid crystal display device that is axially symmetrically aligned with respect to an axis perpendicular to both substrates, where a negative photosensitive resin mixed with spacer beads is coated on one of the substrates, and photolithography is performed. Forming a polymer wall in which spacer beads are partially buried and fixed by a method, and defining the distance between the first substrate and the second substrate by the spacer beads. Bonding process Encompasses the step of forming a liquid crystal layer having a plurality of liquid crystal regions divided in the gap between the substrates by a liquid crystal injected to polymer walls, the objects can be achieved.

The operation of the present invention will be described below.

In the present invention, the cell thickness is defined by spacer beads partially buried and fixed in the polymer wall, and it is necessary to provide columnar projections or increase the height of the polymer wall. Therefore, non-uniformity of the cell thickness due to variation during application of the photosensitive resin can be prevented. Further, since it is not necessary to increase the width of the polymer wall so that the bottom of the columnar projection does not protrude from the polymer wall, it is possible to improve the definition of the liquid crystal display device and improve the brightness of the display.

The spacer beads are mixed with a photosensitive resin material, applied to a substrate, and patterned by a photolithography method, so that the spacer beads are partially buried and fixed in the polymer wall, and are well controlled in the polymer wall portion. Spacer beads can be placed. Therefore, as compared with the conventional manufacturing method, the number of manufacturing steps of the columnar projection by the photolithography method can be reduced, and the alignment of the two is unnecessary.

By providing an inclined portion having a forward tapered cross section with respect to the substrate on the polymer wall, alignment disturbance of liquid crystal molecules existing near the polymer wall in the periphery of the liquid crystal region is less likely to occur. Therefore, it is possible to prevent light leakage in the peripheral portion of the liquid crystal region and to improve the contrast at the time of black display.

In particular, by setting the angle of inclination of the inclined portion to be not less than 5 ° and not more than 45 ° with respect to the substrate, a stable axisymmetric alignment state can be obtained, and the height of the polymer wall can be further reduced. .

If polymer walls are formed using a photosensitive resin (resist), it is not necessary to separately form a resist film at the time of patterning, so that the number of manufacturing steps can be reduced.

If a positive photosensitive resin is used for forming the polymer wall, the photosensitive resin immediately below the spacer beads may not be sufficiently irradiated with light, and the spacer beads may remain in the openings. It is preferable to use a negative photosensitive resin.

If the polymer wall is formed using a transparent resin,
The orientation of the liquid crystal molecules on the polymer wall can also contribute to the display, and the brightness of the display can be greatly improved.
Here, the liquid crystal molecules on the polymer wall are not axially symmetrically aligned,
Since the area is small and the liquid crystal molecules on the wall are oriented in a completely random direction, there is no adverse effect on the display as a whole. Similarly, the brightness of the display can be significantly improved when spacer beads made of a transparent material are used. Further, by reducing the height of the polymer wall, it is possible to suppress the attenuation of light transmitted through the transparent polymer wall portion and improve the light transmittance.

If the width of the polymer wall is at least twice the diameter of the spacer beads, it is sufficient to dispose the spacer beads within the width of the polymer wall so as not to protrude.

[0051]

Embodiments of the present invention will be described below.

In the liquid crystal display device of the present invention, a polymer wall is provided on one of a pair of substrates disposed to face each other with the liquid crystal layer interposed therebetween, and the polymer wall forms a plurality of liquid crystal regions by the polymer wall. Is divided into The operation principle of this liquid crystal display device is the same as that of the conventional ASM mode axially symmetric alignment.
When no voltage is applied, the liquid crystal molecules are oriented in a direction substantially perpendicular to the substrate, and when a voltage is applied, the liquid crystal molecules are oriented axially symmetric about the central axis for each liquid crystal region. Therefore, no matter what direction the observer observes the liquid crystal display device, the change in contrast is small and the viewing angle characteristics can be widened.

In this liquid crystal display device, the cell thickness is defined by spacer beads which are partially buried and fixed in the polymer wall, and the cell thickness is made uniform and the display quality is greatly improved as compared with the prior art. can do.

Hereinafter, more specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1A is a cross-sectional view schematically showing a configuration of one of a pair of substrates disposed to face each other with a liquid crystal layer therebetween in the liquid crystal display device of the present embodiment. (B) is a plan view thereof.

Here, the red (R), green (G) and blue (B) colored resin layers 3 corresponding to the respective picture elements are formed on the glass substrate 1a.
And a BM layer 2 for shielding the gaps between the colored patterns
Are provided. On top of that, an overcoat layer 4 is provided to cover a stepped portion of the color filter surface immediately above the BM layer 2 and to protect the color filter surface.
A transparent electrode 5 made of ITO is provided as a signal electrode.

On top of this, a polymer wall 6 surrounds the picture element.
Are provided, and spacer beads 7 for defining the cell thickness are partially buried and fixed in the polymer wall 6.

As shown in FIG. 2 (e),
A vertical alignment film 8 is formed, and is bonded to the counter substrate 1b on which the vertical alignment film 8 and an ITO electrode (not shown) are formed. A liquid crystal layer made of liquid crystal having negative dielectric anisotropy is sandwiched between the two substrates, and a region surrounded by the polymer wall 6 is defined as a liquid crystal region 9.

This liquid crystal display device is manufactured, for example, as follows.

First, as shown in FIG. 2A, a BM layer 2 for shielding the gap between the red, green and blue colored patterns from light is formed on a glass substrate 1a. As shown in b), red, green and blue colored resin layers 3 were sequentially formed. As a material of the BM layer 2, a material in which carbon fine particles were dispersed in an acrylic photosensitive resin was used. The film thickness is set to 1.0 μm for both the BM layer 2 and the colored resin layer 3,
The composition was applied to a glass substrate by spin coating and formed into a predetermined pattern by photolithography.

Next, as shown in FIG. 2C, an overcoat layer 4 was formed, and a transparent electrode 5 made of ITO was formed thereon. Here, an overcoat material is applied to a thickness of 1.0 μm by spin coating, and an IT
An O film was formed to a thickness of 300 nm by sputtering and patterned.

Subsequently, as shown in FIG. 2D, a polymer wall 6 for axially symmetrically aligning liquid crystal molecules is formed, and spacer beads 7 for defining the cell thickness are formed on the polymer wall 6. Partially buried and fixed. The material of the polymer wall 6 is a negative photosensitive resin CSP-S00 manufactured by Fuji Ohlin Co., Ltd.
Using No. 2, spacer beads made of transparent plastic having a diameter of 5.5 μm were mixed, and the mixture was applied on a substrate to a thickness of 1.0 μm. Thereafter, patterning was performed by proximity exposure using ultraviolet light under the condition that the polymer wall material immediately below the spacer beads was sufficiently photopolymerized by ultraviolet light, with the size of the liquid crystal region being 150 μm × 150 μm. Here, when a positive resist is used as the polymer wall material, the resist immediately below the spacer beads is not sufficiently irradiated with light, and the spacer beads remain in the region where the spacer beads are not desired to remain in the opening. Therefore, it is preferable to use a negative resist.
The width of the polymer wall was set to 15 μm, and the cross section taper angle of the polymer wall was in the range of 5 ° to 45 ° depending on the distance between the mask and the substrate (proxy gap) at the time of proximity exposure. The reason is that the taper angle is 5
If the angle is less than ゜, the force for regulating the alignment of the liquid crystal molecules in an axially symmetric manner is weak. If the angle is more than 45 °, on the contrary, the disorder of the orientation is conspicuous, and the contrast is significantly lowered due to light leakage during black display. Here, the taper angle was 30 °. Next, when development is performed using a CD developer manufactured by Fuji Ohrin Co., Ltd., and rinsing is performed by high-pressure spray of pure water, spacer beads 7 remain only in the portion where polymer wall 6 is formed. Thereafter, post-baking is performed at 240 ° C. for 60 minutes to partially bury and fix the spacer beads 7 in the polymer wall 6.
Thus, the cell thickness becomes 5.5 μm.

Thereafter, as shown in FIG. 2E, a vertical alignment film 8 was formed on this substrate and the counter substrate, and both substrates were bonded to each other, and liquid crystal was injected between the substrates to form a liquid crystal region 9. . Here, JALS-204 (manufactured by Nippon Synthetic Rubber Co., Ltd.)
Is formed by a spin coating method, and the substrates are bonded to each other to form an n-type liquid crystal material (Δε = −4.0, Δn = 0.08, a twist angle unique to the liquid crystal material so that a 90 ° twist is obtained with a cell gap of 6 μm). Setting) was injected to produce a liquid crystal cell.

A voltage of 40 V was applied to the prepared liquid crystal cell.
By applying the voltage, the centering operation of the axisymmetric orientation was performed. Immediately after voltage application, multiple central axes were formed in the initial state,
When voltage was continuously applied, a plurality of central axes became one for each liquid crystal region 9, and one axially symmetric alignment region (monodomain) was formed.

A polarizing plate was arranged in a crossed Nicols state on both sides of the liquid crystal cell to complete a liquid crystal display device.

The liquid crystal region 9 of the obtained liquid crystal display device was observed in a transmission mode using a polarizing microscope (cross Nicol) in a state where no voltage was applied. The results are shown in the schematic diagram of FIG.
Since this liquid crystal display device is in a normally black mode, the liquid crystal region 9 exhibits a dark field when no voltage is applied. In FIG. 3, the polymer wall 6 and the liquid crystal region 9 are schematically shown in different patterns in order to be distinguished from each other. It was not possible to distinguish where the boundary with the liquid crystal region 9 was. Then, as shown in FIG. 3, in the black display state, no light leakage was observed in the entire display cell, and a high-contrast display was obtained.

(Comparative Example 1) FIG. 4A is a cross-sectional view schematically showing the configuration of one of a pair of substrates disposed to face each other with a liquid crystal layer interposed therebetween in the liquid crystal display device of Comparative Example 1. FIG. 4B is a plan view thereof. This liquid crystal display device is a liquid crystal display device having improved viewing angle characteristics using a conventional ASM mode.

Here, the red (R), green (G) and blue (B) colored resin layers 3 corresponding to the respective picture elements are formed on the glass substrate 1a.
And a BM layer 2 for shielding the gaps between the colored patterns
Are provided. On top of that, an overcoat layer 4 is provided to cover a stepped portion of the color filter surface immediately above the BM layer 2 and to protect the color filter surface.
A transparent electrode 5 made of ITO is provided as a signal electrode.

On top of this, a polymer wall 6 surrounds the picture element.
Are provided, and a columnar projection 7a for defining the cell thickness is provided thereon.

As shown in FIG. 5 (e),
A vertical alignment film 8 is formed, and is bonded to the counter substrate 1b on which the vertical alignment film 8 and an ITO electrode (not shown) are formed. A liquid crystal layer made of liquid crystal having negative dielectric anisotropy is sandwiched between the two substrates, and a region surrounded by the polymer wall 6 is defined as a liquid crystal region 9.

This liquid crystal display device is manufactured as follows.

First, as shown in FIGS. 5 (a) and 5 (b), a BM layer 2, a red, green and blue colored resin layer 3 were sequentially patterned on a glass substrate 1a by photolithography. .

Next, as shown in FIG. 5C, the overcoat layer 4 was applied to a thickness of 2.0 μm by spin coating, and an ITO film was formed thereon by sputtering to a thickness of 300 nm. And patterned.

Subsequently, as shown in FIG. 5D, a polymer wall 6 for axially symmetrically aligning the liquid crystal molecules is applied by 3.0 μm by spin coating, and a predetermined pattern is formed by photolithography. Transcribed. Polymer wall width is 40μ
m and the inclination angle was 40 °.

Thereafter, as shown in FIG. 5E, columnar projections 7a for defining the cell thickness were formed on the polymer wall 6 so as to have a thickness of 3.0 μm. The cell thickness is 6.0 μm due to the polymer wall 6 and the columnar projections 7a.

Thereafter, as shown in FIG. 5 (f), a vertical alignment film 8 is formed on this substrate and the opposite substrate, and both substrates are bonded to each other, and liquid crystal is injected between the substrates to form a liquid crystal region 9. ,
A liquid crystal cell was manufactured.

As described above, the liquid crystal display device of this comparative example is
A step for forming the columnar projections 7a is separately required.

In this liquid crystal display device, the unevenness in the coating thickness of the polymer material for columnar projections becomes the cell thickness unevenness as it is, and in a region deviated from the specified cell thickness, the viewing angle characteristic deteriorates.
Good display characteristics could not be obtained due to a decrease in transmittance or the like.

[0079]

As described above in detail, according to the present invention, the columnar projection formed by the photolithography method is unnecessary in the ASM mode liquid crystal display device in which the liquid crystal molecules are axially symmetrically aligned. Therefore, a variation in cell thickness can be prevented as compared with a conventional liquid crystal display device, and display quality can be greatly improved. Also, since no columnar projection is provided on the polymer wall for axially symmetrically aligning the liquid crystal molecules, the width of the polymer wall can be narrowed as compared with the conventional liquid crystal display device, and the transmittance can be improved. The brightness of the display can be improved.

Further, according to the method for manufacturing a liquid crystal display device of the present invention, the number of steps for forming columnar projections can be reduced as compared with the conventional method for manufacturing a liquid crystal display device using the ASM mode, and the cost is accordingly reduced. In addition, the yield can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of one substrate in a liquid crystal display device of an embodiment.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the liquid crystal display device of the embodiment.

FIG. 3 is a diagram illustrating a state in which the liquid crystal display device of the embodiment is observed with a polarizing microscope in a crossed Nicols state when no voltage is applied.

FIG. 4 is a diagram schematically showing a configuration of one substrate in a liquid crystal display device of a comparative example.

FIG. 5 is a cross-sectional view illustrating a manufacturing process of the liquid crystal display device of the comparative example.

FIG. 6 is a diagram for explaining the operation principle of the liquid crystal display device in the ASM mode.

FIG. 7 is a diagram for explaining an alignment state of liquid crystal molecules in a liquid crystal region in an ASM mode liquid crystal display device.

FIG. 8 is a diagram for explaining viewing angle characteristics of an ASM mode and TN mode liquid crystal display device.

FIG. 9 is a cross-sectional view illustrating a manufacturing process of the liquid crystal display device of the comparative example.

FIG. 10 is a cross-sectional view illustrating a configuration of a color filter.

[Explanation of symbols]

 1a, 1b Glass substrate 2 BM layer 3 Colored resin layer 4 Overcoat film 5 Transparent electrode 6 Polymer wall 7 Spacer bead 8 Vertical alignment film 9 Liquid crystal region

Claims (9)

[Claims] 1. A liquid crystal layer made of liquid crystal having negative dielectric anisotropy is sandwiched between a pair of substrates, and the liquid crystal layer is formed of a polymer provided on one of the pair of substrates. It has a plurality of liquid crystal regions divided by walls, and liquid crystal molecules in the plurality of liquid crystal regions are aligned substantially perpendicular to both substrates when no voltage is applied, and centered on an axis perpendicular to both substrates when voltage is applied. 1. A liquid crystal display device which is axially symmetrically oriented as described above, wherein a distance between the two substrates is defined by spacer beads partially buried and fixed in the polymer wall. 2. The liquid crystal display device according to claim 1, wherein the polymer wall has an inclined portion having a forward tapered cross section with respect to the one substrate. 3. The liquid crystal display device according to claim 2, wherein the angle of the inclined portion is not less than 5 ° and not more than 45 ° with respect to the one substrate. 4. The liquid crystal display device according to claim 1, wherein the polymer wall is made of a photosensitive resin. 5. The liquid crystal display device according to claim 1, wherein the polymer wall is made of a negative photosensitive resin. 6. The liquid crystal display device according to claim 1, wherein the polymer wall is made of a transparent resin. 7. The liquid crystal display device according to claim 1, wherein the width of the polymer wall is at least twice the diameter of the spacer beads. 8. The liquid crystal display device according to claim 1, wherein the spacer beads are made of a transparent material. 9. A liquid crystal layer made of liquid crystal having negative dielectric anisotropy is sandwiched between a pair of substrates, and the liquid crystal layer is formed of a polymer provided on one of the pair of substrates. It has a plurality of liquid crystal regions divided by walls, and liquid crystal molecules in the plurality of liquid crystal regions are aligned substantially perpendicular to both substrates when no voltage is applied, and centered on an axis perpendicular to both substrates when voltage is applied. A method of manufacturing a liquid crystal display device having an axially symmetric orientation as described above, wherein a negative photosensitive resin mixed with spacer beads is applied to the one substrate, and patterned by photolithography to form spacer beads. A step of forming a polymer wall partially embedded and fixed, a step of bonding the first substrate and the second substrate together with the spacer beads defining an interval therebetween, and a step of bonding the two substrates. Inject the liquid crystal into the gap Forming a liquid crystal layer having a plurality of liquid crystal regions divided by the polymer wall.