JPH05313148A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To easily produce a liq. crystal display device excellent in brightness and homogeneity and enhanced in antiglaringness. CONSTITUTION:Inorg. oxide layers 23 and 24 and a fluorine-contg. polymer layer 26 are formed on the surfaces of the parts (light-source glass, light transmissive plate, diffusion plate, liq. crystal panel). An excellent reflection reducing effect is obtained by adjusting the refractive index and film thickness of the inorg. oxide and fluorine-contg. polymer formed on the surface. A liq. crystal display device is easily produced by applying a solcontg. the inorg. oxide or a precursor of the inorg. oxide on the surface of the part and further applying a solvent-soluble fluorine-contg. polymer soln.

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 which has a bright display, little surface reflection, and excellent manufacturing stability.

[0002]

2. Description of the Related Art A liquid crystal display device having a backlight is
In general, a cold cathode fluorescent discharge lamp is placed on a side surface, a waveguide plate guides light to the back surface, and the liquid crystal display panel is irradiated with the light through a diffusion plate. A transparent acrylic plate is usually used as the waveguide plate, and achieves a good balance of low power, high brightness, in-plane homogeneity, and thin and lightweight. A product called a direct type, which does not use a light guide plate, is used for products requiring high brightness such as a small television. In addition, a projection type liquid crystal display device and a liquid crystal display device having a reflector without a light source are also used.

[0003]

However, in the conventional liquid crystal display device, the surface reflection of each component through which the light passes causes the light to pass through.
There was a problem that the amount of light above 100% was lost. Further, there is a problem that the display is difficult to see due to surface reflection. As the antireflection coating, it is known to deposit a low refractive index material such as magnesium fluoride, and it is put to practical use in spectacle lenses and the like. However, in the vapor deposition method, there is a problem in the film formation homogeneity on the entire surface in various shapes, and since an expensive vacuum device with poor throughput is required, it is extremely expensive for applications requiring a large area. There was a problem that it would become something like. Although a method of sticking an anti-glare film on the display surface is also taken, there is no anti-glare film having good overall characteristics including transmittance, and a satisfactory effect cannot be obtained.

Therefore, the present invention solves such a problem, and an object thereof is to provide a liquid crystal display device which is excellent in brightness and homogeneity, has a high anti-glare degree and is easy to see, and an easy manufacturing method thereof. It is in.

[0005]

The above object is to provide an inorganic oxide layer and a fluorine-containing polymer layer on the surface of a component through which light passes in a liquid crystal display device having a liquid crystal display panel. To be achieved. A coupling layer may be formed between the two layers. Further, the liquid crystal display device, a sol containing an inorganic oxide or an inorganic oxide precursor is applied to the surface of a component through which light passes, and an inorganic oxide layer is formed by heating, and a solvent-soluble fluorine-containing polymer solution is further formed. It can be produced by forming a fluorine-containing polymer layer by coating.

[0006]

The sol containing the inorganic oxide fine particles or the inorganic oxide precursor such as a hydroxide compound can be prepared by using an organic compound such as alkoxide or acetate as a raw material. When a suitable alcohol or the like is used as the dispersion medium of the sol, it can be applied uniformly on glass or resin without breaking the substrate. Adhesion and film strength can be obtained by heating at a relatively low temperature, and a high refractive index thin film of 1.55 or more can be easily formed by adjusting the type and mixing ratio of inorganic oxides. Taking the refractive index alone as an example, TiO ₂ is 2.
7, CeO ₂ is 2.3, ZrO ₂ is 2.1, Sb ₂ O ₃ is 2.0, Nd ₂ O ₃ is 2.0, and Al ₂ O ₃ is 1.7. It is advisable to mix silica and boric acid components for adjusting the refractive index.

On the other hand, solvent-soluble fluorine-containing polymers have recently been obtained. Since the low refractive index peculiar to the fluorine-containing polymer is maintained and the solvent is soluble in the solvent, a thin film having no pinhole and excellent in visible light transmittance can be easily obtained by coating. Depending on the material, an astonishing characteristic with a refractive index of 1.29 can be obtained. To be used as an antireflection coating, the refractive index of 1.
If it is 40 or less, some effect can be obtained. The solvent that dissolves the solvent-soluble fluorine-containing polymer is an inert fluorine-based solvent and does not violate commonly used glass or resin.

The film thickness normally used for obtaining the antireflection effect is obtained by an integral multiple of (wavelength of light) / 4 (refractive index of film), and is about 0.05 to 0.2 μm. Film formation is easy, and there is almost no attenuation of light due to film absorption. The inorganic oxide layer is not always stable because it cannot be sufficiently heated, but the fluorine-containing polymer layer on the surface also serves as a protective film and has sufficient environmental resistance. However, the adhesion between the inorganic oxide layer and the fluorine-containing polymer layer is low, and it is necessary to interpose a coupling layer such as a silane coupling agent depending on the purpose of use.

[0009]

【Example】

(Example 1) Since the refractive index of "Teflon AF2400" (manufactured by DuPont) is 1.29, the coating conditions were determined so that the film thickness of the fluorine-containing polymer layer on the surface was 1000Å. Further, when the refractive index of the base material is calculated as 1.55, it is preferable that the inorganic oxide layer has a refractive index of 1.61 and a film thickness of about 850Å. Therefore, a coating sol was determined by adjusting a sol having 2-methoxyethanol as a main solvent containing alumina fine particles and a hydrolyzate of ethyl silicate so as to have a refractive index of 1.61.

First, the above-mentioned sol was applied to a transparent acrylic light guide plate and heated to 80 ° C. to form an inorganic oxide layer having a film thickness of 850 Å. Next, "Teflon AF2400" dissolved in a perfluoro solvent was applied onto it, dried at 60 ° C, and a fluorine-containing polymer layer having a film thickness of 1000 Å was laminated.
The film thickness can be sufficiently controlled within the range of about 50Å. It was confirmed by microscopic observation that the thin film formed was extremely dense and homogeneous. The reflectance in air is 0.2 at 550 nm.
%, A high antireflection effect was obtained. Similarly, an inorganic oxide layer and a fluorine-containing polymer layer were formed on the glass surface of the light source lamp.

FIG. 1 shows a schematic cross-sectional view of a liquid crystal display device using the light guide plate and the lamp thus manufactured. In FIG. 1, 11 is a liquid crystal panel, 12 is a diffusion plate,
13 is a light guide plate, 14 is a reflection plate, and 15 is a lamp. Further, 16 is an antireflection layer comprising an inorganic oxide layer formed by the above-mentioned method and a fluorine-containing polymer layer. The brightness on the display surface improved from 60 candela to 70 candela. Almost no in-plane luminance distribution was observed, and a bright and easy-to-see display was achieved. Also, the reliability of heat, humidity, light resistance, etc. was sufficient.

(Example 2) Since the refractive index of "CYTOP CTX" (manufactured by Asahi Glass Co., Ltd.) was 1.34, coating conditions were determined so that the film thickness of the fluorine-containing polymer layer on the surface was 950Å.
Also, the refractive index of the base material was calculated as 1.50, and the first layer of the inorganic oxide layer had a refractive index of 1.64 and a film thickness of about 850Å, and the second layer of the inorganic oxide layer had a refractive index of 2.2. The target value was about 1250Å. Therefore, Sol 1 having ethanol as a main solvent containing tin oxide fine particles and a hydrolyzate of boric acid and methyl silicate was adjusted so as to have a refractive index of 1.64, and coating conditions were determined. In addition, sol 2 containing acetic acid containing a hydrolyzate of cerium acetate and 2-ethoxyethanol as a main solvent was prepared, and coating conditions were determined.

First, the above-mentioned sol 1 is applied to a liquid crystal color display panel to which a polarizing plate is attached and heated to 80 ° C. to obtain a film thickness of 8
A 50Å inorganic oxide layer was formed. Next, sol 2 was applied and heated to 80 ° C. to form an inorganic oxide layer having a film thickness of 1250Å. Next, it was immersed in a 0.5 wt% aqueous solution of aminosilane (SH6020, manufactured by Toray Silicone Co., Ltd.), which is a silane coupling agent, for 2 minutes, washed with water, and then dried at 60 ° C. to form a coupling layer. Further, "Cytop CTX" dissolved in a fluorine-based dedicated solvent (CT-Solv.100) is applied thereon, and dried at 60 ° C to give a film thickness of 9
A 50Å fluorine-containing polymer layer was laminated. The film thickness can be sufficiently controlled within the range of about 50Å. It was confirmed by microscopic observation that the thin film formed was extremely dense and homogeneous, and that cracks and the like did not occur. The reflectance in air was 0.5% or less over the entire visible wavelength range, and a high antireflection effect was obtained. Similarly, the above-mentioned coating was applied to both the glass surface of the light source lamp and both surfaces of the diffusion plate.

FIG. 2 shows an enlarged view of a schematic cross section of the liquid crystal panel thus manufactured. In FIG. 2, 21
Is a glass substrate, 22 is a polarizing plate, 23 is a first inorganic oxide layer, 24 is a second inorganic oxide layer, 25 is a coupling layer,
Further, 26 is a fluorine-containing polymer layer. The brightness on the display surface improved from 70 candela to 80 candela. Almost no in-plane luminance distribution was observed, and a bright display could be achieved. Moreover, the liquid crystal display device has a high degree of anti-glare and is easy to see. Also, the reliability of heat, humidity, light resistance, etc. was sufficient.

(Example 3) Since the refractive index of the copolymer of polydiperfluoroalkyl fumarate and polyvinyl ester is 1.39, the coating conditions are determined so that the film thickness of the fluorine-containing polymer layer on the surface becomes 900 Å. It was Further, when the refractive index of the substrate is calculated as 1.5, the refractive index of the inorganic oxide layer is 2.0 and the film thickness is preferably about 1350Å. Then, a sol containing alumina fine particles and zirconia fine particles and containing 2-methoxyethanol as a main solvent was adjusted so that the refractive index was 2.0, and the coating conditions were obtained.

The above-mentioned sol was applied to a liquid crystal display panel to which a polarizing plate was attached and heated to 80 ° C. to form an inorganic oxide layer having a film thickness of 1350 Å. Next, a copolymer of polydiperfluoroalkyl fumarate and polyvinyl ester dissolved in trifluoromethylbenzene is coated thereon, and 6
It was dried at 0 ° C., and a fluorine-containing polymer layer having a film thickness of 900 Å was laminated. The film thickness can be sufficiently controlled within the range of about 50Å. It was confirmed by microscopic observation that the thin film formed was extremely dense and homogeneous. The reflectance in the air was 0.8% or less in the entire visible wavelength range, and a high antireflection effect was obtained. A liquid crystal display device with a reflector on the back of this liquid crystal display panel
We were able to achieve a bright and easy-to-read display with little surface reflection.

(Example 4) "Teflon AF1600"
Since the refractive index of Dupont (manufactured by DuPont) is 1.31, the coating conditions were determined so that the film thickness of the fluorine-containing polymer layer on the surface was 800 to 1200Å. Further, when the refractive index of the base material is calculated as 1.55, the refractive index of the inorganic oxide layer is 1.63, and the film thickness is preferably about 600 to 1000Å. Then, a sol having a main solvent of 2-methoxyethanol containing fine particles of alumina and a hydrolyzate of ethyl silicate was adjusted so that the refractive index was 1.63, and the coating conditions were determined.

The above-mentioned sol was applied to a liquid crystal display panel for projection having a polarizing plate attached thereto. An inorganic oxide layer with a film thickness of 950Å was formed on the red panel, 800Å on the green panel, and 650Å on the blue panel. Next, "Teflon AF1600" dissolved in a perfluoro solvent was applied thereon, and a fluorine-containing polymer layer having a film thickness of 1200 Å on the red panel, 1000 Å on the green panel and 800 Å on the blue panel was laminated. The film thickness can be sufficiently controlled within the range of about 50Å. It was confirmed by microscopic observation that the thin film formed was extremely dense and homogeneous. The reflectance in air was 0.2% or less in each wavelength range, and a high antireflection effect was obtained.

In the liquid crystal projection device using the parts thus manufactured, the brightness on the screen is 15%.
Improved. Almost no in-plane brightness distribution is observed,
We were able to achieve a bright display. Also, the reliability of heat, humidity, light resistance, etc. was sufficient.

[0020]

As described above, according to the present invention, by providing a liquid crystal display device in which an inorganic oxide layer and a fluorine-containing polymer layer are formed on the surface of a component through which light passes, Therefore, it was possible to create a liquid crystal display device which is excellent in uniformity and high in antiglare degree and easy to see. Since the liquid crystal display device of the present invention is completely the same as the conventional one in terms of component structure, the introduction of the present invention can immediately obtain a great effect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing the concept of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a cross section schematically showing an antireflection layer in Example 2 of the present invention.

[Explanation of symbols]

 11 ‥‥‥‥‥‥ Liquid crystal panel 12 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Glass substrate 22 Polarizing plate 23 First inorganic oxide layer 24 Second inorganic oxide layer 25 Coupling layer 26 Fluorine-containing polymer layer

Claims (5)

[Claims] 1. A liquid crystal display device comprising a liquid crystal display panel, wherein an inorganic oxide layer and a fluorine-containing polymer layer are formed on the surface of a component through which light passes. 2. The liquid crystal display device according to claim 1, wherein the inorganic oxide formed on the surface of the component has a refractive index of 1.55 or more, and the fluorine-containing polymer has a refractive index of 1.40 or less. Item 3. A liquid crystal display device according to item 1. 3. The inorganic oxide formed on the surface of a component of the liquid crystal display device is an oxide containing at least one of titanium, cerium, zirconium, neodymium, antimony, tin, tantalum, and aluminum. The liquid crystal display device according to claim 1. 4. A coupling layer such as a silane coupling agent is formed between the inorganic oxide layer and the fluorine-containing polymer layer formed on the surface of the component in the liquid crystal display device. Liquid crystal display device. 5. In a display device including a liquid crystal display panel, a sol containing an inorganic oxide or an inorganic oxide precursor is applied to the surface of a component through which light passes, and heated to form an inorganic oxide layer, A method for producing a liquid crystal display device, which further comprises forming a fluorine-containing polymer layer by applying a solvent-soluble fluorine-containing polymer solution.