JPH11271751A - Liquid crystal display device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the structure of a liquid crystal display device which has no jaggedness on a screen and a high contrast and can be made lightweight as a cell in two-layered structure, and to provide the manufacturing method for forming the structure. SOLUTION: A color liquid crystal display unit is constituted by stacking a liquid crystal cell for display having liquid crystal sandwiched between substrates having 1st transparent electrodes 21 and a 2nd transparent electrode 22 and a liquid crystal cell for phase correction by the external surface of the 2nd substrate and a 3rd substrate and spacers for holding the gap of the liquid crystal cell for display constant are provided at a black matrix part 61 provided at the peripheral part of a display pixel part on the internal surface of the 2nd substrate and spacers for holding the gap of the cell for phase correction constant are provided on the external surface of the 2nd substrate corresponding to the position of the black matrix part 61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color liquid crystal display device, which comprises a liquid crystal cell for display and a liquid crystal cell for phase correction integrally. The present invention relates to a structure of a color liquid crystal display device having excellent display performance and a method of manufacturing the same.

[0002]

2. Description of the Related Art A conventional color STN (Super Tw)
A liquid crystal display cell having a two-layer structure in an isotropic nematic mode is a display liquid crystal cell in which liquid crystal is sandwiched between a pair of substrates having electrodes, and a phase correction liquid crystal in which liquid crystal is sandwiched between two transparent substrates. 4 consisting of a combination of liquid crystal cells
It is composed of two substrates.

As a prior art in which an integrated two-layer cell structure is formed by using three substrates, for example, Japanese Patent Application Laid-Open No. 9-160016 is disclosed.
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-264, a method for manufacturing a cell body having a two-layer structure is described, but a method for specifying a spacer is not described.

The role of the spacer is used as a means for controlling the distance between the liquid crystal cells. Generally used spacers are often spherical, and have an appropriate strength to maintain the liquid crystal cell distance uniformly. In addition, silica beads or black beads having precise dimensional accuracy are used, and a method of randomly dispersing an appropriate amount on an alignment film that has been subjected to an alignment treatment is employed.

[0005] As a conventional technique for uniformly forming the inter-cell spacing of the first display liquid crystal cell of the two-layer liquid crystal display cell, one of two substrates having electrodes has a particle size. After randomly scattering uniform spherical spacers,
Means is employed in which two substrates are bonded via a sealant to form a uniform gap between the two substrates.

Further, as a conventional technique for uniformly forming the inter-cell spacing of the second phase correction liquid crystal cell, a spherical spacer having a uniform particle size is randomly formed on one of the two substrates. Then, the two substrates are bonded together via a sealant to form a uniform spacing between the two substrates.

When both the display liquid crystal cell and the phase correction liquid crystal cell are formed by the above-described conventional means, spacers are randomly dispersed. A spacer is also arranged at the portion. When the spacer is present in the display pixel portion, the peripheral portion of the spacer is not oriented, so that the image quality and the contrast are reduced.

Here, the structure and manufacturing method of a two-layer cell formed by conventional means will be described below with reference to FIG.

First, a black matrix 61, color filters 51R, G and B, an overcoat film 41, and a transparent conductive film are formed on a second substrate 12 in order to form a display liquid crystal cell shown in layer A of FIG. After lamination, the transparent electrode 2
2 is formed by photolithography.

On the other hand, after a transparent conductive film is also formed on the first substrate 11, the transparent electrode 21 is similarly patterned by photolithography.

Thereafter, the first substrate 11 and the second substrate 12
Alignment films 31 and 3 for aligning liquid crystal on transparent electrodes
2 is formed by a printing method, and both alignment films are subjected to an alignment treatment by a rubbing method.

Next, after a sealant 91 for sealing liquid crystal is formed by printing on the first substrate having a transparent electrode, a spherical spacer 81 is formed on the alignment film 32 of the second substrate.
The liquid crystal cell for display shown in the layer A of FIG. 4 can be prepared by injecting a liquid crystal after the two substrates are overlapped by spraying a at random.

However, the STN liquid crystal display device of this display liquid crystal cell utilizes the birefringence effect of the liquid crystal, so that it is unavoidable that it is colored by interference colors, giving it a bluish or yellow-green tint. The liquid crystal cell for phase correction plays a role for eliminating the blue tint or yellowish green tint.

Next, a brief description will be given of a method of forming the liquid crystal cell for phase correction shown in the layer B of FIG.

First, the third and fourth transparent substrates 13 and 14
The alignment films 33 and 34 for aligning the liquid crystal are formed on the substrate surface serving as the inner surface of the substrate by a printing method, and the alignment processing is performed on both alignment films by a rubbing method.

Next, a sealant 92 for sealing the liquid crystal is formed on the substrate serving as the inner surface of the third substrate 13 by printing. Thereafter, spherical spacers 82a are randomly scattered on the alignment film 34 of the fourth substrate 14, the two substrates are overlapped, and a liquid crystal is injected, whereby a liquid crystal cell for phase correction shown in the B layer of FIG. Can be created.

[0017]

As described above, the STN liquid crystal display device having a two-layer structure in which the layer A of the display liquid crystal cell and the layer B of the liquid crystal cell for phase correction are formed by the conventional means, is as follows. Since the spacers are randomly present in the display pixel portion and the peripheral portions of the spacers are not oriented, the image quality and the contrast are reduced.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems, to provide a liquid crystal display device having a high contrast without a screen roughness and a light weight as a two-layer structure cell. It is to provide a manufacturing method for forming this structure.

[0019]

In order to achieve the above object, the structure of a liquid crystal display device of the present invention and a manufacturing method for forming the structure employ the following means.

The liquid crystal display device according to the present invention comprises a display liquid crystal cell in which liquid crystal is sandwiched between substrates having first and second transparent electrodes, and a phase shift between an outer surface of the second substrate and the third substrate. A color liquid crystal display laminated with a correction liquid crystal cell,
Spacers for keeping the distance between the display liquid crystal cells constant are provided in the black matrix portion provided around the display pixel portion on the inner surface of the second substrate, and correspond to the position of the black matrix portion on the second substrate. And a spacer for keeping the interval between the phase correction cells constant at a position on the outer surface to be formed.

The method for manufacturing a liquid crystal display device of the present invention
Forming a black matrix, a color filter, an overcoat film, and a transparent electrode on the substrate, forming an alignment film on the first substrate and the second substrate, and performing an alignment process for aligning the liquid crystal. Applying a photosensitive resin to the second substrate, irradiating the photosensitive resin with ultraviolet rays using a photomask to dissolve the unexposed portions, and sandwiching the first resin and the second substrate. A plurality of photolitho spacers for maintaining a constant distance between the liquid crystal layers are formed in a black matrix portion provided around the display pixel portion on the inner surface of the second substrate, and the first substrate and the second substrate are formed. A step of forming a first liquid crystal layer by superimposing, and forming an alignment film on an outer surface of a second substrate having the first liquid crystal layer and a third substrate to align liquid crystal. To expose the outer surface of the second substrate. A step of applying a resin, a step of irradiating a photosensitive resin with ultraviolet rays using a photomask to dissolve the unexposed portions, and a step of keeping a distance between the liquid crystal layers sandwiched between the second substrate and the third substrate constant. A plurality of photolithographic spacers for holding are formed at locations on the outer surface corresponding to the positions of the black matrix portions of the second substrate, and the second substrate and the third
Forming a second liquid crystal layer by laminating the substrates.

[Operation] The liquid crystal display device of the present invention comprises a first substrate, a second substrate, and a third substrate, and is a light-shielding portion of a substrate having a color filter of the second substrate. Form multiple photolitho spacers on the inner surface and outer surface of the location corresponding to the position of the black matrix part,
The display pixel portion of the display liquid crystal cell including the first and second substrates and the display pixel portion of the phase correction liquid crystal cell including the second and third substrates have no spacer. As a result, it is possible to provide a high-contrast liquid crystal display device having excellent display quality without light leakage due to the spacers and roughness.

An ordinary STN liquid crystal display device having a two-layer cell structure has a total of four liquid crystal cells for display composed of two substrates having electrodes and a liquid crystal cell for phase correction composed of two substrates. It is composed of two substrates. As described above, in the liquid crystal display device of the present invention, a single color filter substrate having a black matrix constitutes a part of a liquid crystal cell for display and a liquid crystal cell substrate for phase correction. As described above, the STN liquid crystal display device having the two-layer cell structure can be reduced in weight because it is constituted by three substrates.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an STN liquid crystal display device in the best mode for carrying out the present invention and a method of manufacturing the same will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a configuration of a liquid crystal display device according to an embodiment of the present invention and a manufacturing method thereof, and FIG. 2 is a perspective view illustrating the liquid crystal display device of the present invention. Hereinafter, description will be made with reference to FIGS. 1 and 2 alternately.

[Structure of Liquid Crystal Display Device: FIGS. 1 and 2] In the liquid crystal display device of the present invention, as shown in FIG. 1, a liquid crystal cell A layer for display has a transparent electrode 21 inside a first substrate 11. A first substrate 11 having an alignment film 31 that has been subjected to an alignment process;
Black substrate 61, color filter 51, overcoat 41, and transparent electrode 22
And a second substrate 12 having an alignment film 32 that has been subjected to an alignment process and a photolithographic spacer 81 b formed on the alignment film. The liquid crystal layer 71 is sealed by a sealant 91. I have. The uniform spacing between the display liquid crystal cells is maintained via a photolithographic spacer 81b formed on the alignment film 32 corresponding to the position of the light-shielding black matrix portion of the second substrate.

On the other hand, the B layer of the liquid crystal cell for phase correction is shared with the substrate having the alignment film 34 provided with the alignment treatment provided inside the third substrate 13 and the A layer of the liquid crystal cell for display.
And a substrate 12 having a photolitho spacer 82b formed on the alignment film 33 provided on the outer surface of the substrate. The liquid crystal layer 72 is sealed by a sealant 92. The distance between the B layers of the liquid crystal cell for phase correction is the same as that of the second photolithographic spacer 82b formed on the alignment film 33 on the outer surface corresponding to the position of the light-shielding black matrix portion. , A uniform cell spacing is maintained.

The photolithographic spacers 81b, 82b
As shown in FIG. 2, the photolithographic spacer 81b is formed specifically at a position corresponding to the position of the light-shielding black matrix portion 61 provided around the display pixel. There is an effect that the presence of 82b is not recognized and the display quality looks smooth.

As described above, the first display liquid crystal layer 71 and the second phase correction liquid crystal layer 72 are integrated by the second substrate 12, and the first, second, and third three , A two-layer cell is constructed, so that the weight can be reduced as compared with a normal cell composed of four substrates of this kind.

[Method of Manufacturing Liquid Crystal Display Device: FIGS.
FIG. 3] Next, a method for manufacturing the liquid crystal display device of the present invention will be described in detail with reference to FIGS.

First, as shown in FIG.
In order to form a pattern of a black matrix for light shielding, Cr is sputtered on a glass substrate by 120 nm.
m.

Thereafter, as shown in FIG. 2, in order to form a lattice-like black matrix pattern 61, a positive resist ZP (Zeon Japan) is formed on the chromium (Cr) film.
P-1700 (trade name) is applied, and a pattern having a predetermined size is formed by photolithography. Thereafter, a pattern having a black matrix width of 10 μm to 30 μm is formed by etching with a chromium etchant. At this time, a color filter formed in a later process, a transparent electrode,
An alignment mark for positioning a photolithographic spacer or the like is formed on the outer peripheral portion of the substrate.

Then, on a substrate on which the black matrix is formed, a photosensitive pigment-dispersed color filter red base material V-259R (trade name) manufactured by Nippon Steel Chemical Co., Ltd.
Is applied to a predetermined thickness by a spin coating method, and then a color filter red pattern 51 is formed by a photolithography method.

Thereafter, similarly, a color filter pattern is formed in the order of green and blue, and color filters 51 of R, G, B and three colors are formed. This color filter is 1.5μ
m.

Thereafter, as a transparent overcoat film 41 on the upper surface of the color filter 51, Optmer SS6777 (trade name) manufactured by JSR is formed by a spin coating method.
This overcoat film is formed with a thickness of 3 μm. The overcoat film 41 has the chemical resistance of the color filter,
It plays a role in improving the sputtering resistance and the flatness.

Further, a transparent conductive film 22 is provided on the upper surface of the overcoat film 41 by a sputtering method. Thereafter, a positive resist ZPP-1700 (trade name) manufactured by Zeon Corporation is applied on the upper surface of the transparent conductive film 22 by a spin coating method, and then a pattern is formed by a photolithography method to etch the transparent electrode.

Thereafter, a JALS-612 (trade name) alignment film 3 made of polyimide made by JSR is formed on the upper surface of the transparent electrode 22.
2 is formed to a thickness of 60 nm to 80 nm, and a rubbing treatment for aligning the liquid crystal is performed. On the other hand, an alignment film 31 is similarly provided on the transparent electrode 21 of the first substrate 11 having an electrode, and a rubbing process is performed.

Here, in the present invention, in order to keep the distance between the liquid crystal layers of the display liquid crystal cell uniform, a photolitho spacer is formed on the alignment film at a position corresponding to the position of the black matrix portion of the second substrate 12. The following method is adopted as a means.

The black matrix 6 of the second substrate 12
In order to form a columnar first photolitho spacer 81b at a position corresponding to the position 1, the rubbed alignment film 32 is coated on the alignment film 32 to make a negative transparent photosensitive resin N made by JSR.
N-500 (trade name) is applied by a spin coating method.

The thickness of the photosensitive resin is determined by the amount of shrinkage at which the film thickness shrinks in a baking step performed for the purpose of increasing the film hardness in a later step in order to increase the distance between the display liquid crystal cells to, for example, 5 μm. It is applied with a 5.4 μm film thickness.

After that, using a photomask, the photosensitive resin is irradiated with ultraviolet rays in accordance with the alignment mark formed by the black matrix, and then subjected to a developing treatment with an alkali developing solution, whereby the unexposed portions are dissolved. The columnar first photolitho spacer 81b can be formed on the alignment film 32 at a thickness of 5.4 μm on the portion irradiated with the ultraviolet rays.

Thereafter, the second substrate 12 on which the photolithographic spacers 81b are formed is baked at a temperature of 200 ° C., whereby the first columnar photolithographic spacers 81b are thermally cured to function as a 5 μm thick spacer. Will have.

Thereafter, as shown in FIG. 3, a seal 91 for sealing the liquid crystal and a double seal for preventing entry of a chemical solution in a photolithography process for forming a second spacer in a later process. After printing 91a on the first substrate 11, by superimposing the second substrate 12 on the first substrate 11, a display liquid crystal cell A layer having a first layer electrode can be formed. The display liquid crystal cell includes a black matrix 61.
The space between the first substrate and the second substrate is uniformly maintained at the portion corresponding to the position of the portion via the columnar first photolithographic spacer 81b.

The present invention relates to a second liquid crystal cell A layer for display.
The liquid crystal cell B for phase correction is shared with the outer surface of the substrate 12 of FIG.
In order to form the layers integrally and to form the photolithographic spacers 82b at the positions corresponding to the positions of the black matrix portions as in the case of the liquid crystal cell for display, a polyimide alignment film JALS made of JSR is formed on the outer surface of the second substrate 12. A rubbing treatment is performed after printing and forming an alignment film 33. Then, a rubbing process is performed after the alignment film 34 is provided on the third substrate 13 in the same manner.

Thereafter, the second substrate 12 and the third substrate 1 for holding the liquid crystal 72 of the B layer of the liquid crystal cell for phase correction are sandwiched.
Photolitho spacer 8 for maintaining uniform spacing 3
In order to form 2b on the outer surface corresponding to the position of the black matrix portion of layer A of the display liquid crystal cell, photolithography is performed in the following steps.

To form a columnar second photolithographic spacer 82b on the alignment film 33 on the outer surface at a position corresponding to the black matrix portion of the rubbed second substrate 12, a negative type JSR product is used. Photosensitive resin NN-50
0 (product name) is applied by a spin coating method.

Thereafter, using the same photomask used for the first photolithographic spacer 81b formed on the electrode side of the second substrate 12 having the electrodes, a black matrix is formed from the outer surface side of the second substrate 12 using the same photomask. After aligning with the formed mark and irradiating the photosensitive resin with ultraviolet rays, development processing is performed with an alkali developing solution to form a columnar second photolitho spacer 82b.

Here, as shown in FIG. 3, a double seal 91a is applied to the outer peripheral portion of the empty space where the liquid crystal of the display liquid crystal cell of the first layer is to be sealed. Chemicals in the coating step and the developing step are prevented from entering the first-layer display liquid crystal cell, and contamination by the chemicals can be prevented.

Thereafter, the second photolithographic spacer 82b
Is formed at a temperature of 200 ° C. on the display liquid crystal cell A layer, which has the second substrate 12 on which the first layer of liquid crystal is not sealed, at a temperature of 200 ° C.
2b is thermally cured to have a function as a spacer.

Thereafter, after a seal 92 for sealing the liquid crystal in the B layer of the phase correction liquid crystal cell is printed on the third substrate 13, the first display liquid crystal cell having the second photolithographic spacer 82b is provided. By superimposing the layer A on the second layer, the second layer B of the liquid crystal cell for phase correction can be formed. The phase correction liquid crystal cell B layer is the first display liquid crystal cell A.
Similarly to the layer, the second substrate 12 and the third substrate 13 are provided at positions corresponding to the positions of the black matrix portions of the second substrate 12 via the second columnar photolitho spacers 82b.
Is maintained uniformly.

Thereafter, the dummy seal portion 91a on the outer peripheral portion of the double seal for preventing entry of the chemical solution formed on the outer peripheral portion of the display liquid crystal cell of the first layer was scribed, and the break was removed. Thereafter, liquid crystal is injected from a sealing portion having a liquid crystal injection hole of the first display liquid crystal cell A layer and the second layer of the phase correction liquid crystal cell B layer, and the injection hole is sealed to form two layers. An STN liquid crystal display device having a cell structure can be manufactured.

According to the above STN liquid crystal display device, both the first display liquid crystal cell A layer and the second phase correction liquid crystal cell B layer have photolithography only at locations corresponding to the positions of the black matrix. Since a structure in which a spacer is present can be formed, and no spacer is present in the display pixel portion observed by a viewer, a high-contrast image display with smooth image quality can be obtained.

The STN color display device of this embodiment,
As a result of measuring and comparing the contrast characteristics of the conventional display device shown in FIG.
A value of 40 is shown in the conventional example with respect to a value of 0. In the conventional display device, since the spacer is present in the display pixel portion, the periphery of the spacer is not aligned and the contrast is reduced due to light leakage. However, in the present invention, high contrast characteristics are obtained.

[0053]

As is apparent from the above description, according to the present invention, the first-layer display liquid crystal cell and the second-layer phase correction liquid crystal cell of the STN display device having a two-layer structure are: Since the spacer formed by the photolithography method is provided in the black matrix portion that is not observed by the viewer, the spacer does not cause a decrease in the contrast ratio or the spacer portion is not rough due to disorder in the alignment of liquid crystal molecules. Further, one color filter substrate having a black matrix constitutes a part of the liquid crystal cell for display and the liquid crystal cell substrate for phase correction. Since the liquid crystal display device is constituted by three substrates as described above, the weight of the liquid crystal display device can be reduced. Therefore, according to the present invention, a color STN display device having high display quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a partial perspective view showing a structure of the liquid crystal display device according to the embodiment of the present invention.

FIG. 3 is a plan view showing the method for manufacturing the liquid crystal display device according to the embodiment of the present invention and showing a double seal.

FIG. 4 is a cross-sectional view showing a conventional liquid crystal display device having a two-layer structure.

[Explanation of symbols]

 11, 12, 13, 14 Substrate 21, 22 Transparent electrode 31, 32, 33, 34 Alignment film 41 Overcoat film 51 Color filter 61 Black matrix 71, 72 Liquid crystal layer 81a, 82a Spherical spacer 81b, 82b Photolitho spacer 91, 92 Seal 91a Dummy seal A layer Liquid crystal cell for display B layer Liquid crystal cell for phase correction

Claims (2)

[Claims] 1. A display liquid crystal cell in which a liquid crystal is sandwiched between substrates having a first transparent electrode and a second transparent electrode, and a phase correction liquid crystal cell between an outer surface of a second substrate and a third substrate. A stacked color liquid crystal display, wherein a spacer for keeping a distance between display liquid crystal cells constant is provided in a black matrix portion provided around a display pixel portion on an inner surface of the second substrate; A liquid crystal display device comprising: a spacer for maintaining a constant interval between the phase correction cells at a position on the outer surface corresponding to the position of the black matrix portion of the substrate. 2. A black matrix on a second substrate,
Forming a color filter, an overcoat film and a transparent electrode, forming an alignment film on the first substrate and the second substrate, and performing an alignment process for aligning liquid crystal; A step of applying a photosensitive resin to the substrate, a step of irradiating the photosensitive resin with ultraviolet rays using a photomask to dissolve unexposed portions, and a step of forming a liquid crystal layer sandwiched between the first substrate and the second substrate. A plurality of photolithographic spacers for keeping the interval constant
Forming a first liquid crystal layer by forming a first liquid crystal layer by overlapping a first substrate and a second substrate on a black matrix portion provided around a display pixel portion on the inner surface of the first substrate; Forming an alignment film on the outer surface of the second substrate and the third substrate, performing alignment processing for aligning liquid crystal, and applying a photosensitive resin to the outer surface of the second substrate. Irradiating the photosensitive resin with ultraviolet rays using a photomask to dissolve the unexposed portions; and a plurality of steps for maintaining a constant distance between the liquid crystal layers sandwiched between the second substrate and the third substrate. The photolitho spacer is
Forming a second liquid crystal layer by superposing the second substrate and the third substrate on the outer surface corresponding to the position of the black matrix part of the substrate. A method for manufacturing a display device.