JPS62258427A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve contrast by spraying a gap agent intended to maintain a specified cell gap only in the non-display part. CONSTITUTION:A film 3-1 of a polyimide having the property to orient liquid crystal molecules parallel with a substrate is formed on the surface of an upper glass substrate 1-1. A film 3-2 of the polyimide is formed only on the non- electrode part of a lower glass substrate 1-2 and a gap material 5 is fixed to the substrate surface by the film. The light transmitting the gap material 5 in the stage of shielding the light, the leakage of the light by the disturbed orientation around the material 5 and the leakage of the light from the discrimination generated from the gap material are thereby eliminated and therefore, the transmittance of the light in the stage of shielding the light is decreased and the contrast is improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the structure of a liquid crystal display device.

[Conventional technology]

In a conventional liquid crystal display device, a film for aligning liquid crystal molecules parallel to and in the same direction as the substrates is formed on at least 10,000 of a pair of substrates having electrodes, and the film containing the substrate casing material is coated over the entire surface of the substrates. It had a structure in which the N2 tag material was spread evenly across the entire area and faced each other.

[Problem that the invention attempts to solve]

However, in the above-mentioned prior art, since the gap material is also spread over the display area, there is still light that passes through the gap material itself even when light is blocked, resulting in a decrease in contrast. However, when using ferroelectric liquid crystals, in addition to the aforementioned light transmission through the gap material itself, there is also light leakage due to disordered orientation around the gap material, and disclination caused by the gap material. The contrast of the ferroelectric liquid crystal display device R? is significantly reduced due to light leakage. When used as a liquid crystal light valve, this has been a very serious problem.

Therefore, the present invention aims to solve these problems.
The purpose of this is the light leakage caused by the gap material 11-? ! <I. The present invention provides a liquid crystal display device with a high contrast ratio.

[Means for solving problems]

The liquid crystal display device of the present invention is characterized in that a gap material for the purpose of keeping the cell gap at a constant level is sprinkled only on the non-display portion of the liquid crystal display device.

[Effect]

According to the above configuration of the present invention, since the gap material is not scattered in the display area, light leakage occurs due to light passing through the gap material itself, and light is caused by disordered orientation around the gap material. The leakage n is completely eliminated, and the amount of disclination generated by the gap material applied to the display area is reduced, so the light leakage j when light is blocked becomes extremely small, resulting in high contrast.

[Example 1] FIG. 1 is a main sectional view showing one embodiment of the present invention.

1-1"lr upper glass substrate, with a polyimide film 3- on the surface that has the property of aligning liquid crystal molecules parallel to the substrate.
1 is formed. 1-2 is a lower glass substrate;
Polyimide (hereinafter referred to as PI) film 3 only on the non-electrode part
-2 is formed, and the gap material 5 is fixed to the substrate surface by this film. 2-1.2-2 is a transparent electrode, which is covered with a thin film of indium oxide + tin oxide (hereinafter referred to as ITO) all around.

Hereinafter, the method for manufacturing this liquid crystal display device will be described. First, ITO is formed on the entire surface.1. Apply a positive resist to a total thickness of 1.5 μm on a glass substrate using a spinner at 90°C.
Spend 3[] minutes on the screen. After that, a photo mask? Use this to expose unnecessary parts other than the electrodes. KOH's 1
Use a 2% aqueous solution to register unnecessary parts other than the electrodes)?
Peel and then apply Hc l! ? ITO etching solution containing ITO as the main component removes unnecessary parts other than electrodes.
? etching. Next is the resist left on the electrode? Second
After exposure, aromatic polyamic acid solution (Toshi, 5p-7
40) Coat the entire surface of the i-substrate to a thickness of 500 μm using a printing method, and then uniformly scatter spherical gear material with a diameter of 25 μm. FIG. 6 is a cross-sectional view of the glass substrate after the gap material has been sprayed, and the gap material is partially embedded in the aromatic polyamic acid solution film.

After baking at 140°C for 60 minutes to fix the gap material in polyimide, the substrate was immersed in a 30°C (1.2°C) aqueous solution of KOH for 760 seconds to form a bond on the electrode. This substrate, which was peeled off and then post-painted at 250° C. for 1 hour to imidize, was used as the lower substrate. FIG. 4 is a sectional view of the lower substrate constructed by the above method.

Upper board in the usual way! The material that had been subjected to electrode formation, PI film formation, and rubbing was used. After forming a seal on the upper substrate using screen printing, the upper and lower substrates are bonded together via the gap material, and a cell with a substrate spacing of 2 μm is assembled. Ferroelectric liquid crystal is injected into this fCo cell, sealed, and ISO →SmC"'f and then slowly cooled at ℃/111n to make the entire cell orientation uniform.In this liquid crystal display device, there is no gap material in the display area. Since the light leakage f1-1 due to the orientation disorder n around the gap material and the light dissipation from the disclination generated by the gap material are completely eliminated, the gap material can also be spread over the conventional display area. Compared to a liquid crystal display device, the amount of transmitted light when light is blocked is extremely small at 1/10 to 1/30, and the contrast ratio is also considerably higher, 10 to 30 times compared to conventional displays. .

[Example 2] FIG. 2 is a main sectional view showing one embodiment of the present invention.

6 is nickel plated to block transmitted light in non-display areas and to reduce wiring resistance.Nickel plating is applied to the parts of the lower substrate on which the 0 sweet electrodes are formed that need to block light and reduce resistance. did. Is this a resin that has the property of becoming soluble in a specific solvent only in the areas that are exposed to light? It was applied using a spinner. After the gap material is uniformly spread over the entire substrate, light is irradiated from the back side of the substrate.

FIG. 5 is a sectional view of the lower substrate immediately after the gap agent has been sprayed. Then, use a solvent to remove the resin film on the display area.
It was peeled off along with the gap agent.

On the upper substrate, electrodes were formed, a PI film was formed, and
The one that had been rubbed was used. After the entire seal was printed on the upper substrate using screen printing, a cell with a cell gap of 2 μm was assembled. When the ferroelectric liquid crystal was completely injected into this cell and slowly cooled, there was no gap material in the display area, so no light leakage due to the gap material was observed and the contrast was high.

[Example 3] In Example 2, a resin that had the property of dissolving in a specific solvent was used in the part that was exposed to light, but a resin that had the property of curing in the part that was exposed to light was applied to the surface of the substrate using a spinner. After applying it with , Clean and remove the gap agent on the display part 1 ~,
It was also effective to use this substrate as the lower substrate.

[Example 4] In Examples 1 to 3, when a ferroelectric liquid crystal was used, and when liquid crystal light pulp was produced using a TN liquid crystal, light leakage due to the gap agent (n, vy<t~, contrast) ? [Effects of the Invention] As described above, according to the present invention, the overall purpose of the present invention is to maintain a constant cell gap only in the non-display portion of the liquid crystal display device. By dispersing the gap agent, there will be no light passing through the gap agent when light is blocked, light leakage due to disordered orientation around the gap agent, and light leakage from disclination caused by the gap agent. This has the effect of reducing the light transmittance during light blocking and increasing the contrast ratio.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the liquid crystal display device of the present invention. FIG. 2 is a sectional view showing an embodiment of the liquid crystal display device of the present invention. FIG. 6 is a sectional view of the lower substrate of the liquid crystal display device of FIG. 1 after the gap agent has been sprayed. FIG. 4 is a cross-sectional view of the lower substrate of the liquid crystal display device of FIG. 1 after the resist is removed. FIG. 5 is a cross-sectional view of the lower substrate of the liquid crystal display device of FIG. 2 after the gap agent has been sprayed. 1-1... Upper glass substrate 1-2... Lower glass substrate 2-1.2-2... Transparent electrode 5-1.3-2... Alignment film 4... Sealing agent 5...Gap agent 6...Resist 7...Nickel plating or higher

Claims (1)

[Claims] A liquid crystal display device comprising a ferroelectric liquid crystal sandwiched between a pair of substrates, characterized in that a gap agent for maintaining a constant cell gap is sprayed only on non-display portions of the liquid crystal display device. Display device.