JP2582935C - - Google Patents

Description

The present invention relates to a liquid crystal display device, and more particularly to preventing line-shaped lighting unevenness caused by static electricity in a manufacturing process. (B) Conventional technology A liquid crystal display device has a structure as shown in FIG. A transparent electrode 3 patterned in a predetermined shape and an alignment film 4 covering the transparent electrode 3 are formed on the upper and lower surfaces of the glass substrate 2.
A liquid crystal material is injected between the two glass substrates, and the periphery of the glass substrates is sealed with a sealant 6. In order to keep the distance between the liquid crystal cells constant, the spacer members 7 are uniformly dispersed, and the distance between the liquid crystal cells is generally 4 to 30 μm. Finally, the polarizing plates 1 are arranged on both outer sides of the glass substrate, and the liquid crystal display cell is completed. By the way, this polarizing plate has a laminated structure of an insulating film, and has the property of being easily charged with static electricity. By the way, it is well known that when a protective film provided on a polarizing plate is peeled off from the polarizing plate body, several hundreds to several thousand volts of static electricity are generated. In a liquid crystal display device, as typified by the example of generation of static electricity accompanying the peeling of the protective film on the polarizing plate described above, in the manufacturing process, there are many opportunities to generate static charge and discharge. There has been a problem that a display irregularity of the liquid crystal display device due to the discharge, particularly a defect due to a linear lighting irregularity occurs. (C) Problems to be Solved by the Invention As in the above-described example of the generation of static electricity due to the peeling of the protective film on the polarizing plate, when the electrostatic charge is generated outside the liquid crystal layer material, the charge of this charge is Correspondingly, an electric double layer is formed, and as a result, static electricity (potential difference) is also generated inside the liquid crystal layer material (inside the two glass substrates of the liquid crystal display device). In a state where the liquid crystal display device static in is charged, the terminal portion of the liquid crystal display device is in contact with the electrical conductor (i.e. the body volume that specific resistance is low), such as a metal, a discharge path is formed. The charge state of the alignment film (FIG. 3-4) and the spacer (FIG. 3-7) located on the transparent electrode of the liquid crystal cell in the region serving as the discharge path locally changes, and as a result, the liquid crystal display The threshold voltage of the device will change locally. For this reason,
Traces (regions) of the discharge path are visually recognized as linear lighting unevenness, and the display quality of the liquid crystal display device is significantly deteriorated. One solution to this problem is to dispose a conductive tape or the like at the terminals of the liquid crystal display device (part of FIG. 2-8) and to cause discharge caused by contact of a good electrical conductor such as metal to the terminals. It is known to prevent the formation of paths by dispersing them over a large area and by dispersing them between a number of electrodes of a liquid crystal cell. An example of the conductive tape is, for example, Cu7636R (trade name) manufactured by Sony Chemical Corporation. However, the charging phenomenon and the discharging phenomenon from the terminal portion of the liquid crystal display device also occur in the process of connecting the liquid crystal display device to the driving circuit. Is difficult and troublesome, and it is difficult to actually use it. Further, this "conductive tape" is composed of a conductive layer / base film / adhesive layer, and has a major drawback that when the conductive tape is removed, a charging phenomenon and a discharging phenomenon occur due to peeling. (D) Means for Solving the Problems According to the present invention, a conductive resin composition is provided in a terminal area existing outside a sealing material of a liquid crystal display device, and the conductive resin composition is There is provided a liquid crystal display device having a volume resistivity of 10 ² Ωcm to 10 ⁸ Ωcm, which does not substantially change in a heating step. The terminal area of the liquid crystal display device according to the present invention refers to the terminal area shown in FIG.
In the figure (front view), it means the terminal portion 8. 2 and 1, 1 is a polarizing plate, 2 is a glass substrate, 3 is a transparent electrode, 4 is an alignment film, 5 is a liquid crystal layer, 6 is a sealing material, and 7 is a spacer material. The conductive resin composition of the present invention is provided including the outside of the sealing material. This arrangement is performed by applying a conductive resin composition (usually used as a paste). Coating can be performed according to a conventional method. The width of the coating is (0.3 to 1 mm) × (10 ×) when the gap between the liquid crystal cells is about 4 μm to 10 μm.
10 cm). The timing of the application is usually preferably after the liquid crystal layer is sealed. The conductive resin composition of the present invention has a volume resistivity of 10 ² Ωcm to 10 ⁸ Ω.
Adjusted to indicate cm. This resistance value does not substantially change even when subjected to a heat treatment in the manufacturing process of the liquid crystal cell. <Relationship between resistance value and uneven charging> Such a conductive resin composition is usually composed of a conductive substance and an organic binder, and a solvent is further used to form a paste. Examples of the conductive substance include aromatic compounds that can be chemically oxidized and polymerized (for example, aromatic compounds such as pyrrole, thiophene, and furan).
Conductive polymers obtained by oxidative polymerization of membered ring compounds and their substituted products, aromatic hydrocarbons such as benzene, naphthalene, anthracene, etc., and coating these conductive polymers on the core material of organic or inorganic compounds And an organic electrolyte are used. As the oxidizing agent used for chemically oxidatively polymerizing the aromatic compound, a conventionally known oxidizing agent can be used, and examples thereof include ferric chloride, cupric chloride, and chlorinated chloride.
Chlorides such as tin, molybdenum chloride, tungsten chloride and ruthenium chloride; sulfates such as copper sulfate and ferric sulfate; potassium dichromate, oxides such as manganese oxide and lead oxide; ammonium persulfate and potassium persulfate , Barium oxoacids such as sodium hypochlorite, sodium chlorate, hydrogen peroxide; metal chlorides such as potassium tetrachloroplatinate (II), sodium tetrachlorovanadium (II), sodium tetrachloroaurate; iodine, bromine And the like. The concentration of the oxidizing agent during the chemical oxidative polymerization can be appropriately selected from the range of 0.001 mol / l to the saturation concentration, and is particularly preferably about 0.01 to 5.0 mol / l. The solvent used for chemically oxidatively polymerizing the aromatic compound is not particularly limited, and a solvent in which the aromatic compound is soluble may be used. For example, a solvent such as water, acetonitrile, benzonitrile, nitrobenzene, methanol, ethanol, tetrahydrofuran (THF) is used. The temperature and time for the polymerization may be arbitrarily selected depending on the type of the oxidizing agent and the solvent to be used and the desired volume resistivity, and are usually in the range of 0 to 100 ° C. and 10 minutes to 24 hours. The volume resistivity of the obtained conductive polymer is 1 × 10 ^-1 to 1 × 10 ⁵ Ωcm, and more preferably 1 × 10 ^-1 to 1 × 10 ³ Ωcm. That is, in order to obtain a conductive polymer having a volume resistivity value of less than 10 ^-1 Ωcm, stretching treatment is required, which is not practical. On the other hand, if it is 10 ⁵ Ωcm or more, the conductivity is insufficient and the predetermined performance cannot be expressed. The method of chemically oxidatively polymerizing the aromatic compound may be a commonly used method.For example, a method in which an oxidizing agent is dissolved in water, and a solution in which the aromatic compound is dissolved in an appropriate solvent as necessary are used. A method of adding is used. The conductive polymer obtained by the above method can be filtered off to remove the solvent, washed with water and / or washed with a solvent, and then isolated as a powder by ordinary means such as drying under reduced pressure. When an aromatic compound having a substituent is used, a liquid conductive polymer can be obtained by the same operation as described above. Further, an organic or inorganic substance having at least a surface coated with a conductive polymer may be obtained, for example, by adsorbing / impregnating an oxidizing agent to polymer fine particles having an anionic functional group, and then adding the aromatic compound to obtain an aromatic compound. it can be obtained by a method of polymerizing the compound. On the other hand, as the organic electrolyte, one or more selected from organic sulfonates, organic sulfates, salts of organic sulfates, salts of organic phosphates and salts of organic carboxylic acids can be used. As the kind of the salt, amines such as amine quaternary salts and ammonium salts, and metals such as sodium and potassium can be used. Specific examples of these organic electrolytes are shown below. In organic sulfonic acids and organic sulfuric acids (esters), dodecyl sulfonic acid, dodecyl benzene sulfonic acid, p-toluene sulfonic acid, dimethyl sulfate, naphthalene sulfonic acid, amine salts of polystyrene sulfonic acid, metal salts such as sodium and potassium are used. Can be used. Examples of such sulfonic acid industrially produced are, for example, NACURE 155 and NACURE 155 manufactured by Kusumoto Kasei Co., Ltd.
1051, NACURE X49-110, NACURE 3525, NACU
RE 2500X and NACURE 5225 can be exemplified. In the organic phosphoric acid system, amine salts, phosphoric acid, dodecyl phosphoric acid, di-dodecyl phosphoric acid, tri-dodecyl phosphoric acid, ammonium salts, metal salts such as sodium and potassium can be used. As such a phosphate-based amine salt industrially produced, there is NACURE4054 (all trade names) manufactured by Kusumoto Kasei Co., Ltd. Further, in the case of organic carboxylic acids, amine salts such as acetic acid, maleic acid, polyacrylic acid and polymethacrylic acid, and metal salts such as ammonium salts, sodium and potassium can be used. These can be used alone or in combination of two or more. Among the above, use of dodecylbenzenesulfonic acid or dinonylnaphthalenesulfonic acid (eg, NACURE3525), which has a relatively high decomposition temperature, is preferred. As the organic binder used in the present invention, a commonly used coating binder resin can be used. For example, a thermoplastic resin such as an acrylic, vinyl, cellulose, or vinyl chloride / vinyl acetate copolymer, or a thermosetting resin as described below can be used. As the thermosetting resin, a known thermosetting resin such as a phenol resin, a urea resin, an amino resin, an alkyd resin, a silicon resin, a furan resin, a polyester resin, an epoxy resin, and a polyurethane resin can be used. Especially phenolic resin,
Amino resins and epoxy resins are preferred. Examples of the phenol resin include resins obtained by adding and condensing aldehydes such as formalin and furfural to those having a phenolic hydroxyl group such as phenol, cresol, xylesol, p-alkylphenol, chlorophenol, bisphenol A, phenolsulfonic acid, and resorcinol. be able to. Particularly, a resol type phenolic resin is preferable. When a novolak-type phenolic resin is used, it is preferable to use hexasamethylenediamine in combination. Examples of the amino resin include a resin in which formalin is added and condensed to an amino group such as urea, melamine, guanamine, aniline, and sulfonamide, and an alkyl etherified melamine resin is preferable. As a catalyst used to cure the melamine resin, p- toluenesulfonic acid, in the case of using the amine salts of strong acids such as naphthalene sulfonic acid as conductive material, nothingness because dissociated acid is a curing catalyst It cures the catalyst, it is preferable that in the case of using other amine salts has been premixed with an organic acid such as linoleic acid as a catalyst. Examples of the alkyl etherified melamine resin include ethyl melamine resin of Super Beckamine L-105-60 manufactured by Dainippon Ink and Chemicals, Super Beckamine J-802-60, J-840, L-117-60, L- 127-60, L
-109-50 n-butylated melamine resin, Super Beckamine G-821
60, L-118-60, L-121-60, TD-139-60, L-110
-60, L-125-60, 47-508-60, L-145-60, L-11
And 6-70 iso-butylated melamine resin (all are trade names). As the epoxy resin, diepoxides of bisphenols are preferable. For example, Epicoat 827,828,834,1001,1002 manufactured by Shell Chemical Co., Ltd.
, 1004, 1007, 1009, Araldite GY manufactured by Ciba Geigy Corporation
-250, 260, 280, 6071, 6084, 6097, 6099, and Epicron 810, 1000, 1010, 3010 (all trade names) manufactured by Dainippon Ink and Chemicals, Inc. Further, as an epoxy resin, for example, a novolak resin having three or more epoxy groups on average.
Epoxy resins can be used. As these novolak epoxy resins, those having a molecular weight of 500 or more are suitable. The following are industrially produced with such a novolak epoxy resin, for example. Araldite EPN1138, 1139, ECN1237 manufactured by Ciba-Geigy Corporation
, 1280, 1299, DEN431, 438 manufactured by Dow Chemical Co., Ltd., Epicoat 152, 154 manufactured by Shell Chemical Co., Ltd., EP manufactured by Union Carbide Co., Ltd.
R-0100, ERRB-0447, ERLB-0488, EOCN series manufactured by Nippon Kayaku Co., Ltd., and the like. If necessary, a curing catalyst or a diluent for an epoxy resin can be used. Is a curing catalyst for epoxy resins, diethylene triamine, triethylene, tetramine, tetraethylene, aliphatic amines such as pentamine, benzyl dimethylamine, diaminodiphenylmethane, aromatic amines such as diaminodiphenyl sulfone, maleic anhydride, phthalic anhydride An acid, hexahydrophthalic anhydride, methylnadic anhydride, p-dimethylaminobenzoaldehyde, trifluoroboric acid / piperidine complex, or the like can be used. As a diluent for the epoxy resin, n-butyl glycidyl ether, len oxide, phenyl glycidyl ether, styrene oxide, allyl glycidyl ether, reactive diluents such as glycidyl methacrylate, dibutyl phthalate,
Non-reactive diluents such as dioctyl phthalate, tricresyl phosphate, cellulose triacetate, xylene, castor oil, pine oil, etc .; Reactive diluents can be used. The aforementioned curable resins used in the present invention may be used alone or in combination of two or more. Furthermore, the mixing ratio of the organic binder in the present invention is determined by the amount of the conductive substance 1
The amount is 5 to 85 parts by weight, preferably 10 to 45 parts by weight with respect to 0 parts by weight. When the amount is less than 5 parts by weight, the absolute amount of the organic binder is insufficient, and the fluidity of the obtained composition becomes poor. , Printability is reduced. If the amount of the organic binder exceeds 85 parts by weight, on the contrary, the absolute amount of the conductive substance is insufficient, and the required conductivity cannot be obtained. Examples of the solvent used for the conductive resin composition include benzene, toluene, hexanone, dioxane, solvent naphtha, industrial gasoline, cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, and dimethyl. Known solvents include formamide, dimethylacetamide, and alcohol-based solvents such as isopropanol and butanol, ketone-based solvents such as methyl ethyl ketone and methyl cis-butyl ketone, and ester-based solvents such as amyl acetate, isoamyl acetate, and butyl acetate. The amount of the solvent varies depending on the type of the kneader, the kneading conditions and the type of the solvent. It is preferable to adjust the amount of the solvent so that the paste viscosity after kneading can be screen-printed. In order to produce the conductive paste of the present invention, for example, a binder is dissolved in a solvent, and then a thermosetting resin and a conductive substance are added, and this is kneaded sufficiently evenly with a disper, a pole mill or three rolls. Prepare a conductive paste. In addition, the conductive resin composition of the present invention has a volume resistivity value of substantially 10 ² Ωcm to 10 ⁸ Ωcm without substantially changing in a heat treatment after application. During this time, it has been confirmed that it is effective in preventing charging unevenness and in the problem of line leakage. In addition, the measurement of the volume resistivity value of the conductive resin composition was performed by the following method. That is, screen printing is performed on a glass-epoxy substrate, and the volume resistivity before and after the curing treatment is measured by a two-terminal method under a DC voltage of 20 V (26 ° C./60% RH).
Atmosphere / Measurement device was R8340A digital ultra-high resistance meter manufactured by Advantest Corporation. The volume specific resistance was calculated by the following equation. Volume specific resistance (Ωcm) = R × t × W / L where R: resistance between electrodes (Ω), t: thickness of coating film (cm), W: width of coating film (cm), L : Distance between electrodes (cm). (E) Embodiment Next, the present invention will be described with reference to embodiments, but the present invention is not limited thereto. Hereinafter, "parts" means parts by weight. Reference Example 1 50 parts of ferric chloride (hexahydrate, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 130 parts of methanol. To this solution was added 20 parts of pyrrole (manufactured by Tokyo Chemical Industry Co., Ltd.),
For 5 hours. The obtained polypyrrole was filtered / washed with water and isolated and purified as a powder. The volume resistivity of the obtained polypyrrole was 1.2 × 10 ¹ Ωcm. Reference Example 2 A liquid conductive polymer was obtained in the same manner as in Reference Example 1, except that 3-hexylthiophene was used instead of pyrrole. The volume resistivity of the obtained polythiophene was 6.5 × 10 ² Ωcm. Example 1 2.2 parts of polyvinylphenol as a binder, 4.0 parts of isobutylated melamine as a thermosetting resin, and polypyrrole 0 obtained in Reference Example 1 as a conductive substance
. 5 parts, and 0.3 parts of butyl carbitol as a solvent were weighed, and 30 parts were rolled with three rolls.
Kneaded for a minute. The volume resistivity of the obtained conductive paste was 2.5 × 10 ³ Ωcm. Next, a liquid crystal display panel in which this conductive paste was applied to a cell gap of 7.5 μm, an application width of 0.6 mm, a length of 150 mm, and 250 mm was manufactured, and subjected to a heat treatment at 120 ° C. for 1 minute. The volume resistivity value of the conductive paste after this heating is up to 4 × 1
0 ³ Ωcm. The structure of the terminal portion of the liquid crystal display panel is as follows.
25 mm, the spacing between the lead wires is also ~ 0.125 mm (that is, the pitch between the wires is 0.250 mm), and the line resistance in this case is an insulation resistance of ~ 0.2 MΩ.
(That is, 200 KΩ) or more. As a result, the effect of preventing charging unevenness was confirmed, and the problem of line leakage did not occur. Example 2 The same operation as in Example 1 was carried out except that the polythiophene 0.9 substance obtained in Reference Example 2 was used as the conductive substance, and the volume resistivity of the obtained conductive paste was 4.5. × 10 ⁶ Ωcm. Next, a cell gap of 9.0 μm and a coating width of 0.5 to 0.7 mm were applied to the conductive paste.
To produce a liquid crystal display panel coated to a length of 150 mm and 240 mm.
Heat treatment was performed at 30 ° C. for 30 seconds. The specific resistance of the conductive paste after heating is up to 7
× 10 ⁹ Ωcm or so. The structure of the terminal portion of the liquid crystal display panel is the same as that of the embodiment, and the width of the lead line is 0.125 mm, and the distance between the lead lines is also
The line resistance in this case was 0.125 mm (that is, the line pitch was 0.250 mm), and the insulation resistance was １００100 MΩ or more. As a result, the effect of preventing charging unevenness was confirmed, and the problem of line leakage did not occur. Example 3 Polyvinylphenol (50% butyl carbitol solution) 2 as a binder
. 0 parts, isobutylated melamine (60% butanol solution) 1 as thermosetting resin
. 0 parts, NACURE X49-110 (manufactured by Kusumoto Kasei Co., Ltd.)
0.5 part of dinonylnaphthalenedisulfonic acid amine salt) and 1.0 part of methyl ethyl ketone as a solvent were weighed and kneaded with a three-roll mill for 30 minutes. Next, a liquid crystal display panel in which this conductive paste was applied to a cell gap of 7.5 μm, an application width of 0.8 mm, a length of 150 mm, and 250 mm was manufactured.
Heat treatment for a minute. The volume resistivity of the conductive paste after this heating is ~ 1 ×
It was 10 ⁵ Ωcm. The structure of the terminal portion of the liquid crystal display panel is as follows.
The distance between the lead wires was 125 mm and the distance between the lead wires was also 0.125 mm (that is, the line width pitch was 0.250 mm). In this case, the line-to-line resistance had an insulation resistance of 4 MΩ or more. As a result, the effect of preventing charging unevenness was confirmed, and the problem of line leakage did not occur. Example 4 Polyvinylphenol (50% butyl carbitol solution) 2 as a binder
. 0 parts, 1.0 part of acrylic resin (60% MEK solution), 0.43 parts of linoleic acid, 1.5 parts of sodium polystyrene sulfonate (molecular weight: 50,000) as a conductive substance, and 1.0 part of ethanol as a solvent Was weighed and kneaded with a three-roll mill for 30 minutes. The volume resistivity value of the obtained conductive paste was 2.7 × 10 ⁷ Ωcm.
This was applied to a liquid crystal panel in the same manner as in the other examples, and the heat treatment at 150 ° C. for 1 minute resulted in a resin having a volume resistivity of 9.4 × 10 ⁷ Ωcm. Also in this case, the effect of preventing charging unevenness was confirmed, and no problem of line-to-line leakage occurred. (F) Effect of the Invention In the liquid crystal display device according to the present invention, after the liquid crystal layer is sealed with the sealing material, the specific conductive resin composition is applied to the terminal region including the outside of the sealing material. The composition has a moderate volume resistivity value and can prevent problems of charging unevenness and line-to-line leakage caused by contact of a metal or the like with a terminal portion in a manufacturing process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a liquid crystal display device according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a sectional view of a conventional liquid crystal display device. DESCRIPTION OF SYMBOLS 1 ... Polarizing plate, 2 ... Substrate, 3 ... Transparent electrode, 4 ... Alignment film, 5 ... Liquid crystal layer, 6 ... Sealing material, 7 ... Spacer material, 8 ... Application part of conductive paste .

Claims (1)

[Claims] 1. A conductive resin composition is provided in a terminal area existing outside a sealing material of a liquid crystal display device, and a volume specific resistance value of the conductive resin composition is 10 ² Ωcm to 10 ^8.
A liquid crystal display device which is substantially unchanged in a heating step at Ωcm. 2. The apparatus according to claim 1, wherein the conductive resin composition contains a conductive substance and an organic binder as essential components. 3. 3. The device according to claim 2, wherein the conductive substance is a conductive polymer obtained by oxidative polymerization of an oxidatively polymerizable aromatic compound or an organic substance or an inorganic substance coated with the conductive polymer. 4. 3. The device according to claim 2, wherein the conductive substance is an organic sulfonate.