JP3210513B2 - LCD substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-based liquid crystal display element substrate which is excellent in light weight, heat resistance, transparency, adhesion to a transparent electrode and the like, and is suitable for forming a liquid crystal cell.

[0002]

2. Description of the Related Art With the enlargement of the screen of a liquid crystal cell and the like, conventional glass substrates are liable to be broken and heavy, so that thin and light resin substrates are being studied. However, resin substrates have disadvantages in that they are inferior in heat resistance, surface hardness, and adhesion to transparent electrodes such as ITO as compared with glass substrates, and various attempts have been made to overcome them.

Heretofore, as a means for overcoming the above problems, a method of evaporating an inorganic substance such as silica on a resin substrate and a method of providing a hard coat film of a silicone or acrylic type have been known.
However, an inorganic vapor-deposited resin substrate has a problem that adhesion between the inorganic vapor-deposited layer and the resin substrate is poor, and a resin substrate provided with a hard coat film such as an acrylic resin has heat resistance, surface hardness, and adhesion to a transparent electrode. There is a problem that the effect of improving the performance is insufficient.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to develop a substrate for a liquid crystal display device which is excellent in light weight, heat resistance, transparency and adhesion to a transparent electrode.

[0005]

According to the present invention, there is provided an inorganic oxide comprising a thermosetting resin having a glass transition temperature of 150 ° C. or higher and at least one surface of a transparent resin substrate used as a liquid crystal cell substrate without an anchor agent coating. Thickness of 0.3
It is coated with a transparent film of single layer ～20Myuemu, the transparent film of the inorganic oxide is Ri Do from hydrolysis and polycondensation of a metal alkoxide, a liquid crystal display, wherein good adhesion to the transparent electrode It is intended to provide an element substrate.

[0006]

According to the above structure, a liquid crystal having excellent lightness, heat resistance, transparency and adhesion to a transparent electrode is formed on the basis of a transparent coating layer of an inorganic oxide comprising a hydrolyzed / polycondensate of the metal alkoxide. A display element substrate is obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The substrate for a liquid crystal display element of the present invention comprises a transparent resin substrate coated on at least one side with a transparent film of an inorganic oxide composed of a hydrolyzed / polycondensed metal alkoxide. Examples thereof are shown in FIGS. 1 is a transparent film of an inorganic oxide, and 2 is a transparent resin substrate. As is clear from the figures, the substrate for a liquid crystal display element of the present invention may be such that the transparent resin substrate is coated on both sides or the entire surface with a transparent film of the inorganic oxide.

[0008] The transparent film of the inorganic oxide in the present invention,
It is formed by hydrolysis and polycondensate of metal alkoxide. As the metal alkoxide, an appropriate metal alkoxide, such as alkoxysilane, alkoxyaluminum, alkoxytitanium, alkoxyantimony, or alkoxyzircon, which forms a transparent inorganic oxide by hydrolysis and polycondensation can be used.

A metal alkoxide which can be preferably used from the viewpoint of ease of reaction and the like is alkoxysilane, and particularly, a compound represented by the general formula: (However, R ¹ , R ² , R ³ , and R ⁴ are the same or different and are alkyl groups having 1 to 4 carbon atoms).

Incidentally, specific examples of the alkoxysilane represented by the above general formula include, for example, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane and tetra-silane. Tetraalkoxysilanes such as sec-butoxysilane, tetra-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-
Propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane,
Methyl triisopropoxy silane, ethyl triisopropoxy silane, isopropyl triisopropoxy silane, n-propyl triisopropoxy silane, methyl tri-n-propoxy silane, ethyl tri-n-propoxy silane, isopropyl tri-n-propoxy silane, n- Propyltri-n-propoxysilane, γ-chloropropyltriisopropoxysilane, γ-chloropropyltri-n
-Monoalkyl trialkoxy such as propoxysilane, methyldimethoxyisopropoxysilane, methylmethoxydiisopropoxysilane, ethyldiethoxyisopropoxysilane, ethylethoxydiisopropoxysilane, methyldiethoxyisopropoxysilane, methylethoxydiisopropoxysilane Silane and the like.

The transparent film is formed by, for example, dissolving a solution in which a metal alkoxide and water are dissolved in a suitable hydrophilic solvent such as alcohol on a transparent resin substrate by a suitable method such as a casting method, a spin coating method, and a dipping method. The method can be carried out by, for example, developing and subjecting the metal alkoxide to hydrolysis and polycondensation while evaporating water and a solvent by evaporating water and a solvent, if necessary, to obtain an inorganic oxide. Therefore, the transparent film made of the inorganic oxide is formed as a single layer film on the transparent resin substrate without the interposition of the anchor agent film. The thickness of the transparent film to be formed is 0.3 to 20 μm, preferably 0.1 to 20 μm. It is 5 to 5 μm.

In preparing the developing solution, two or more metal alkoxides can be used. Further, the pH of the developing solution is set at 2 from the viewpoint of promoting the hydrolysis / polycondensation reaction.
It is preferable to adjust to ~ 5. Nitric acid,
An appropriate acid such as hydrochloric acid or acetic acid can be used. The hydrolysis / polycondensation reaction of the metal alkoxide proceeds even at room temperature, but it is preferable to heat at 80 to 200 ° C. for 30 to 120 minutes from the viewpoint of promptly performing the reaction.

Incidentally, the hydrolysis and polycondensation reaction of the metal alkoxide described above is represented by the following formulas (1) and (2) using tetraalkoxysilane as an example. (1) Si (OR ² ) ₄ + 4H ₂ O = Si (OH) ₄ + 4R
² OH (2) Si (OH) ₄ = SiO ₂ + 2H ₂ O

Therefore, when the hydrolysis / polycondensation reaction of the metal alkoxide proceeds 100%, a transparent film of 100% of an inorganic oxide such as SiO ₂ in the case of a silane alkoxide is formed. When a group or an organic group such as R ¹ or R ² in the above general formula remains, a transparent film containing an organic component is formed. In the present invention, it is preferable that the transparent film does not contain such an organic component. However, when the organic film contains an organic component, the content of the transparent film is preferably 20% by weight or less in terms of the adhesion of the transparent electrode. More desirable.

In the present invention, the inorganic oxide particles 11 may be dispersed and contained in the transparent film 1 as shown in FIG. By containing such inorganic oxide particles, a transparent film having an uneven structure can be formed on the surface, whereby the adhesion of a transparent electrode or the like can be further improved by an anchor effect or the like based on the uneven structure.

As the inorganic oxide particles, for example, silica,
Appropriate particles exhibiting transparency in a transparent film, such as alumina, titanium oxide, antimony oxide, and zirconia, can be used. Alumina particles are preferred from the viewpoint of the present invention. The size of the particles is appropriately determined depending on the thickness of the transparent film to be formed and the like, but is preferably 0.1 μm or less, particularly preferably 0.05 μm or less from the viewpoint of the transparency of the formed film.

The formation of the transparent film containing the inorganic oxide particles comprises
For example, in the preparation of the developing solution described above, one or two or more kinds of inorganic oxide particles may be mixed and dispersed, and a method of forming a transparent film using the developing solution may be used. The content of the inorganic oxide particles in the transparent film is 85
% By weight or less. When the content exceeds 85% by weight, the adhesion to the transparent resin substrate is reduced,
A brittle transparent film may be formed.

Examples of the transparent resin substrate of the target to provide a transparent film, from the point is for a liquid crystal cell that need to provide a transparent electrode consisting of I TO deposited film or the like, Ri by the viewpoint of the heat resistance and the like at the time of vapor deposition having a glass transition temperature of at least 1 50 ° C.
A thermosetting resin is used. Further, from the viewpoints of preventing deterioration of the liquid crystal in the cell and the life of the cell, those having excellent chemical resistance, transparency, optical isotropy, low water absorption, low moisture permeability, and gas barrier properties such as oxygen are preferable.

Generally used for forming a transparent resin substrate
Examples of said resins, et epoxy resins, unsaturated polyesters, polydiallyl phthalate, etc. poly isobornyl methacrylate. One or more of such resins may be used, and may be used as a copolymer or a mixture with other components.

The transparent resin substrate which can be preferably used from the viewpoint of heat resistance and the like is made of an epoxy resin, particularly a cured product of an epoxy composition containing an epoxy resin, an acid anhydride curing agent and a phosphorus curing catalyst. is there. As the epoxy resin, various epoxy resins such as bisphenol type and novolak type, alicyclic type and polyfunctional type can be used,
There is no particular limitation.

Examples of the acid anhydride-based curing agent include phthalic anhydride, 3.6 endmethylenetetrahydrophthalic anhydride, succinic anhydride, maleic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride. Acid, methyltetrahydrophthalic anhydride, etc., among which colorless or pale yellow acid anhydrides such as hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride can be preferably used. . The compounding amount of the acid anhydride-based curing agent is preferably 0.5 to 1.3 equivalents per epoxy equivalent in the epoxy resin.

Examples of the phosphorus-based curing catalyst include alkyl phosphines, phosphine oxides, and phosphonium salts. The amount of the acid anhydride-based curing agent 10
0.2 to 10 parts by weight, preferably 0.5 to 4 parts per 0 parts by weight
Parts by weight are preferred.

The transparent resin substrate is formed by, for example, a casting method, a transfer molding method, a casting method, an injection molding method, a roll coating method, an extrusion method, a casting method, a reaction injection method (RIM). It can be performed by an appropriate method such as Upon its formation, if necessary, for example, a dye, a denaturant, a discoloration inhibitor, an antioxidant,
Appropriate additives such as an ultraviolet absorber, a release agent, a reactive diluent, and a non-reactive diluent can be appropriately compounded as long as the transparency is not impaired.

The thickness of the transparent resin substrate to be formed is preferably 1 mm or less, more preferably 0.5 mm or less from the viewpoint of thinning and lightness. The thickness of the transparent resin substrate may be achieved as a laminate of two or three or more layers of the same or different resins as described above. Therefore, the transparent resin substrate may be formed as a resin single layer or a laminate thereof.

The substrate for a liquid crystal display element of the present invention comprises a cell base
Although Ru Der those used for forming the liquid crystal cell as a plate, a wavelength 60 by a spectrophotometer based specifically on the case of the thickness of 0.4mm
Those exhibiting a transparency of 0 nm light of 60% or more, particularly 80% or more, are preferably used. When the substrate for a liquid crystal display element of the present invention is put to practical use, a functional film such as a gas barrier layer or a hard coat layer for the purpose of reducing gas permeability may be provided, or may be joined to a retardation plate or a polarizing plate. You can also. Therefore, the substrate for a liquid crystal display element of the present invention can be put to practical use as a multi-layered product composed of, for example, an overlap with various functional layers having the same as a base layer.

The above-mentioned liquid crystal cell can be formed by, for example, a method of forming a transparent electrode pattern on a liquid crystal display element substrate, arranging the transparent electrode patterns opposite to each other, and enclosing liquid crystal between the liquid crystal display element substrates. The formation of the transparent electrode or pattern is based on a conventional method such as a method of depositing a transparent electrode forming material such as tin oxide, indium oxide, gold, platinum and palladium by a sputtering method or a method of applying a transparent conductive paint. Can be done with An alignment film for liquid crystal alignment provided on a transparent electrode as needed can be similarly formed by a conventional method. The liquid crystal cell to be formed is arbitrary such as TN type, STN type, TFT type, and ferroelectric liquid crystal type.

Example 1 A mixture consisting of 100 parts (parts by weight, the same applies hereinafter) of a bisphenol A type epoxy resin having an epoxy equivalent of 185, 95 parts of methylhexahydrophthalic anhydride and 1 part of triphenylphosphine was poured into a mold and heated at 100 ° C. 2 hours, then 17
A curing treatment was performed at 0 ° C. for 16 hours to obtain a transparent resin substrate having a thickness of 0.4 mm.

Next, 30 parts of tetraethoxysilane, 45 parts of isopropyl alcohol, 30 parts of water and 0.06% of acetic acid
The solution obtained by mixing the parts was applied on the transparent resin substrate, and heated at 170 ° C. for 1 hour to provide a transparent film having a thickness of 2 μm, thereby obtaining a liquid crystal display element substrate. The content of the organic component in the transparent film was measured by NMR analysis and found to be 10% by weight or less.

Example 2 A transparent film was formed in the same manner as in Example 1 except that 30 parts of methyltrimethoxysilane was used instead of tetraethoxysilane to obtain a substrate for a liquid crystal display device. The content of the organic component in the transparent film was 10% by weight or less.

Example 3 A solution obtained by dispersing 10 parts of silica particles having an average particle size of 0.02 μm in a solution obtained by mixing 30 parts of tetraethoxysilane, 60 parts of isopropyl alcohol, 30 parts of water and 0.06 part of acetic acid was used. A liquid crystal display element substrate was obtained in the same manner as in Example 1 except that a transparent film was formed using the method. The content of the organic component in the transparent film was 10% by weight or less.

Example 4 A solution obtained by dispersing 10 parts of alumina particles having an average particle size of 0.02 μm in a solution obtained by mixing 30 parts of methyltrimethoxysilane, 60 parts of isopropyl alcohol, 30 parts of water and 0.06 part of acetic acid. A substrate for a liquid crystal display element was obtained in the same manner as in Example 1 except that a transparent film was formed using The content of the organic component in the transparent film was 10% by weight or less.

Comparative Example A transparent resin substrate according to Example 1 without a transparent film was used as it was as a substrate for a liquid crystal display device.

Evaluation On the transparent film of the liquid crystal display device substrate obtained in the example or on the transparent resin substrate as the liquid crystal display device substrate obtained in the comparative example, a thickness of about 0 made of ITO was sputtered. A .1 μm transparent electrode was provided and heated at 150 ° C. for 1 hour, and the change in state was examined. The surface resistance of the transparent electrode on the substrate was 40Ω / □ in each case.

As described above, in any of the examples, no change in appearance was observed on the entire substrate including the transparent electrode after heating, and the surface resistance of the transparent electrode was 40Ω.
/ □ did not change from before heating. On the other hand, in the case of the comparative example, the transparent electrode was cracked, peeled off, and showed no conductivity.

[0035]

According to the present invention, it is possible to obtain a liquid crystal cell substrate excellent in light weight, heat resistance, transparency, and adhesion to a transparent electrode. It is possible to form a liquid crystal cell which achieves approximately 60% weight reduction while achieving image quality equivalent to that of the above, and is excellent in moisture resistance and impact resistance.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a cross-sectional view of another embodiment.

FIG. 3 is a sectional view of still another embodiment.

[Explanation of symbols]

 1: transparent film of inorganic oxide 11: inorganic oxide particles 2: transparent resin substrate

Continued on the front page (72) Inventor Norio Kawamoto 1-1-2 Shimohozumi, Ibaraki-shi, Osaka, Japan Inside Todenko Co., Ltd. (72) Inventor Kiichi Shimohira 1-2-1, Shimohozumi, Ibaraki-shi, Osaka, Japan (56) References JP-A-4-132638 (JP, A) JP-A-63-162549 (JP, A) JP-A-3-256004 (JP, A) JP-A 55-114563 (JP) JP, A) JP-A-4-247427 (JP, A) JP-A-3-50244 (JP, A) JP-A-3-50242 (JP, A) JP-A-3-256003 (JP, A) JP 59-26943 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1333 500 G02B 1/10

Claims (6)

(57) [Claims] 1. A transparent resin substrate having a glass transition temperature of 150 ° C. or higher and a transparent resin substrate used as a liquid crystal cell substrate, wherein at least one surface of the transparent resin substrate is made of an inorganic oxide having a thickness of 0.3 to 0.3 mm without an anchor agent coating. it is coated with a transparent film of a single layer at 20 [mu] m, Ri Do a transparent coating hydrolysis and polycondensation of the metal alkoxide of the inorganic oxide, a transparent electrode
A substrate for a liquid crystal display device, characterized by having good adhesion to the substrate. 2. The metal alkoxide has a general formula: The substrate for a liquid crystal display device according to claim 1, wherein the substrate is an alkoxysilane represented by the following formula (where R1, R2, R3, and R4 are the same or different alkyl groups having 1 to 4 carbon atoms). . 3. The organic content of the transparent film is 20% by weight.
The liquid crystal display element substrate according to claim 1, wherein 4. The substrate for a liquid crystal display device according to claim 1, wherein the transparent film contains inorganic oxide particles dispersed therein. 5. The substrate for a liquid crystal display device according to claim 4, wherein the inorganic oxide particles are particles made of silica, alumina, titanium oxide, antimony oxide, and zirconia. 6. The substrate for a liquid crystal display element according to claim 1, wherein the transparent resin substrate is made of a cured product of an epoxy composition containing an epoxy resin, an acid anhydride curing agent and a phosphorus curing catalyst.