JPH1073827A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which obviates the occurrence of unequal colors in spite of a change in a cell gap and with which an inputting person does not have a flabby feel. SOLUTION: Color filters 3 having black masks 2 are formed on a color filter substrate 1 and an overcoating layer 4 is formed thereon. Transparent electrodes 5 are formed on this overcoating layer 4 and after electrode patterns are formed, a photosensitive oriented film 6 consisting of a photosensitive resin is formed. Photosensitive SiO2 is applied thereon and is subjected to patterning, by which spacers 7 are formed. Next, the photosensitive oriented film 6 is scanned by controlling the irradiation energy and irradiation direction of polarizing UV rays and is thus subjected to a photochemical and physical orientation treatment. On the other hand, transparent electrodes 5 are formed on a counter substrate 9 and electrode patterns are formed. Next, an oriented film 10 is formed. The color filter substrate 1 which is subjected to the orientation treatment by a rubbing method and the counter substrate 9 are stuck to each other via a sealing material and a liquid crystal material 11 is injected therebetween, by which the liquid crystal display device is obtd.

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 for a direct-view type display device such as a transmission type or a reflection type, a projection type display device and various information processing devices. A spacer for controlling the distance between a pair of substrates on which an alignment film for controlling the alignment of the liquid crystal material is formed,
The present invention relates to a liquid crystal display device arranged only in a non-pixel region.

[0002]

2. Description of the Related Art A liquid crystal display device has a structure in which a pair of substrates, at least one of which has a light-transmitting property, is arranged at a predetermined distance, and a liquid crystal material is injected between the pair of substrates.

In order to maintain the above-mentioned predetermined interval,
For example, after the spacers are dispersedly arranged on the surface of the substrate on the liquid crystal material side, the pair of substrates is bonded to each other, so that the distance between the pair of substrates is kept substantially equal to the size of the spacer. Heretofore, the spacers have been distributed over substantially the entire area of the surface of the substrate facing the liquid crystal material.

[0004] When dispersing spacers on a substrate, if the spacers are present in a region (pixel) actually involved in display, the spacers exhibit optical anisotropy different from that of a liquid crystal material. Light leakage occurs, which causes a problem of lowering contrast.

In order to solve such a problem, a method has been proposed in which spacers are dispersed only in non-pixel regions. As a method of dispersing spacers only in non-pixel regions, a method of dispersing spacers only in non-pixel regions using a thermoplastic resin, a method of dispersing spacers only in non-pixel regions using electric potential, A method of dispersing and disposing them in a black mask has already been proposed.

[0006]

A method of dispersing and disposing spacers only in non-pixel regions using a thermoplastic resin is as follows.
Before applying the alignment film, a thermoplastic resin film is formed on the substrate, and after patterning the thermoplastic resin film, the spacers are sprayed and heated, thereby bonding and fixing the spacers only to the non-pixel regions. Is the way.

Therefore, when the alignment film is applied by the offset printing method or the flexographic printing method, the spacer may be peeled off from the substrate when the relief is pressed onto the substrate. Will adhere to

Further, when the alignment film is applied on the next substrate, the spacer attached to the relief plate is transferred to the substrate. Since the transferred spacer is not fixed on the substrate, it is peeled off in the subsequent rubbing step, washing step, etc., particularly when the spacer is transferred on the pixel area, the area where the transferred spacer is peeled off is oriented. This results in a state where no film is formed.

In other words, when a pinhole is present on the alignment film and the liquid crystal display device is completed, it becomes impossible to align the liquid crystal at the pinhole portion on the alignment film, resulting in poor display and non-defective products. Has a problem such as a decrease in

In the rubbing step, the rubbing cloth comes into contact with the spacer fixed on the substrate.
The fluff of the rubbing cloth in contact with the spacer is disturbed. The alignment film rubbed at the portion where the nap of the rubbing cloth is disturbed has a variation in the tilt angle, so that when it is completed as a liquid crystal display device, display defects occur.

Further, the spacers adhered and fixed to the non-pixel regions may be peeled off during rubbing, and if rubbing is continued in that state, the alignment film will be damaged, resulting in a display failure and a decrease in non-defective products. It also has the problem of causing

The method of dispersing and disposing the spacer only in the non-pixel region using the electric potential is performed by charging the spacer and charging the non-pixel region to a polarity opposite to that of the spacer.
This is a method of attaching a spacer to a non-pixel region.

However, since the spacers scattered in the sealed device settle down and adhere to the substrate, if the potential difference between the spacers and the non-pixel regions is small, the spacers adhere to the pixel regions as well. When completed as a liquid crystal display device, there is a problem that light leaks from a spacer existing on the pixel region, leading to a reduction in contrast.

Conversely, when the potential difference between the spacer and the non-pixel region is large, when the liquid crystal display device is completed,
There is also a problem that a display defect occurs due to the charged spacers and non-pixel regions, which lowers the non-defective rate. Further, in an active matrix type liquid crystal display device, the active element may be broken.

In the method of disposing the spacers in the black mask, the rubbing is performed after the spacers are fixed to the black mask. The fur of the cloth is disturbed. The alignment film rubbed at the portion where the nap of the rubbing cloth is disturbed has a variation in the tilt angle, so that when it is completed as a liquid crystal display device, display defects occur.

The present invention has been made in view of the above-mentioned conventional problems, and has a high contrast. When input is performed by adding a touch panel or the like, a cell gap changes and color unevenness occurs. It is an object of the present invention to provide a liquid crystal display device that does not cause an input person to feel a feeling of swelling.

[0017]

In order to achieve the above object, a liquid crystal display device according to a first aspect of the present invention controls a distance between a pair of substrates on which an alignment film for controlling alignment of a liquid crystal material is formed. In a liquid crystal display device in which spacers are arranged only in non-pixel regions, the spacers are columnar made of a photosensitive resin, and the alignment film of at least one of the substrates is subjected to alignment treatment with ultraviolet rays.

The liquid crystal display device according to the second aspect is the first aspect.
In the liquid crystal display device described above, the spacer is present in a ratio of 25 to 50% with respect to the length of each side of the pixel.

According to the liquid crystal display device of the present invention, a columnar spacer made of a photosensitive resin is formed only in the non-pixel region, and the alignment film is aligned by ultraviolet rays.
Since there is no spacer present on the pixel region, it is possible to prevent light scattering at the spacer and a decrease in contrast due to light leakage from the spacer.

Further, when input is performed by adding a touch panel or the like, the cell gap does not change and color unevenness does not occur, so that the input user does not feel a swelling feeling.

Further, since the alignment processing by rubbing is not performed on the substrate on which the spacers are formed, display defects due to rubbing are eliminated, and it is not necessary to charge the spacers. Also, destruction of the active element and the like do not occur.

When a photosensitive resin in which a black pigment is dispersed is used as the spacer, the contrast can be improved.

Also, since the spacer is present at a rate of 25 to 50% with respect to the length of each side of the pixel,
The change in the cell gap can be suppressed without causing any problem when the liquid crystal material is injected.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 is a cross-sectional view of a liquid crystal display device according to the present invention, FIG. 2 is a cross-sectional view illustrating an alignment process of the liquid crystal display device according to the present invention, and FIG. 3 is a plan view illustrating a spacer of the liquid crystal display device according to the present invention. It is.

As shown in FIG. 1, a color filter 3 having a black mask 2 is formed on a color filter substrate 1 made of glass by, for example, an electrodeposition method, and an overcoat layer 4 made of an acrylic resin is formed on the color filter 3. The coating is formed by spin coating.

On the overcoat layer 4, a transparent electrode 5 made of ITO is formed to a thickness of 200 nm by, for example, a sputtering method, and an electrode pattern is formed by a photolithography method. Then, an azo photosensitive polyimide or polysiloxane is formed. A photosensitive alignment film 6 made of a photosensitive resin is applied to a thickness of 40 nm by spin coating.

A photoresist is applied on the photosensitive alignment film 6 to a thickness of 5 μm by spin coating, and is patterned by photolithography to form a spacer 7 made of photoresist. The resist is removed.

As a material of the spacer 7, a photosensitive epoxy resin, a photosensitive polyimide, a photosensitive acrylic resin, or the like can be used. These materials need not be transparent and may be colored. In particular, a black pigment obtained by dispersing a black pigment is preferable.

Next, as shown in FIG. 2, scanning is performed by controlling the irradiation energy and irradiation direction of the polarized ultraviolet light 8, and the photosensitive alignment film 6 is photochemically and physically aligned.

On the other hand, as shown in FIG. 1, a transparent electrode 5 made of ITO is formed to a thickness of 200 nm on a counter substrate 9 made of glass by, for example, a sputtering method, and an electrode pattern is formed by a photolithography method.

Then, an alignment film 10 made of polyimide is formed to a thickness of 50 nm, and the alignment film 10 is subjected to an alignment treatment by a rubbing method.

Color filter substrate 1 after orientation treatment
And the counter substrate 9 are bonded together via a sealing material, and the liquid crystal material 11 is injected to obtain a liquid crystal display device.

As shown in FIG. 3, it is preferable that the spacer 7 is present at a ratio of 25 to 50% with respect to the length of each side of the pixel 12.

If the spacer 7 is less than 25% of the length of each side of the pixel 12, it is difficult to suppress a change in the cell gap, and when input is performed by adding a touch panel or the like, color unevenness occurs. Occurs, and the input person feels a feeling of swelling.

If the spacer 7 is at least 50% of the length of each side of the pixel 12, it takes a lot of time to inject the liquid crystal material 11, and the throughput is significantly reduced.

As described above, since there is no spacer in the pixel area, the contrast is high, and when input is performed by adding a touch panel or the like, the cell gap does not change and color unevenness does not occur. In addition, it is possible to obtain a liquid crystal display device in which the input person does not feel a feeling of swelling.

[0037]

As described above, according to the liquid crystal display device of the present invention, a columnar spacer made of a photosensitive resin is formed only in a non-pixel region, and the alignment film is aligned by ultraviolet rays. Since there is no spacer present on the pixel region, a liquid crystal display device with high contrast can be obtained.

Furthermore, when input is performed by adding a touch panel or the like, the cell gap does not change and color unevenness does not occur, and the input user does not feel a feeling of swelling.

Furthermore, since the alignment processing by rubbing is not performed on the substrate on which the spacers are formed, display defects due to rubbing are eliminated, and it is not necessary to charge the spacers. Also, destruction of the active element and the like do not occur.

If a photosensitive resin in which a black pigment is dispersed is used as the spacer, the contrast can be further improved.

Further, since the spacer is present at a rate of 25 to 50% with respect to the length of each side of the pixel,
The change in the cell gap can be suppressed without causing any problem when the liquid crystal material is injected.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view illustrating an alignment process of the liquid crystal display device according to the present invention.

FIG. 3 is a plan view illustrating a spacer of the liquid crystal display device according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 color filter substrate 2 black mask 3 color filter 4 overcoat layer 5 transparent electrode 6 photosensitive alignment film 7 spacer 8 polarized ultraviolet 9 counter substrate 10 alignment film 11 liquid crystal material 12 pixel

Claims (2)

[Claims] 1. A liquid crystal display device in which a spacer for controlling a distance between a pair of substrates on which an alignment film for controlling alignment of a liquid crystal material is formed is disposed only in a non-pixel region, the spacer has a columnar shape made of a photosensitive resin. A liquid crystal display device, wherein the alignment film of at least one of the substrates is subjected to an alignment treatment by ultraviolet rays. 2. The liquid crystal display device according to claim 1, wherein the spacer is present at a rate of 25 to 50% with respect to the length of each side of the pixel.