JPH10221699A - Manufacture of liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal display element with good workability and with a sufficient liquid crystal orienting characteristic without damaging an orienting film by coating the composition of a radical polymn. type acrylic optical hardening resin on an injecting port after injecting liquid crystal, irradiating specified light so as to harden the composition and sealing the injection port. SOLUTION: Relating to the liquid crystal display element, liquid crystal stuck to the periphery of the injecting port is wiped away after the injection of liquid crystal and the composition of the resin is instantaneously coated on the injecting port. The coated composition of the resin being the sealing material 7 is optically hardened so as to seal the injecting port 6 of the liquid crystal display element 8. That is, the composition (sealing material) 7 of the radical polymn. type acrylic and/or polyene/thiol optical hardening resin is coated on the injecting port 6, light with 350-500nm wave length is irradiated to the composition or wave-unlimited ultraviolet light is irradiated by optically shielding an orienting film surface by a mask material and the composition is hardened so as to seal the injecting port 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display element used as a thin, lightweight, low power consumption display.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been widely used in various fields as thin, lightweight, and low power consumption displays, and their use will be further increased in the future.

In general, a liquid crystal display device has a structure shown in FIG.
As illustrated in (b), an alignment film 1 with an innermost
The glass electrode substrates 2 are fixed with a sealing material 4 while maintaining a constant interval by a spacer 3, and the liquid crystal 5 is filled with an injection port 6.
Then, the injection port is sealed with a sealing material 7 so that the liquid crystal does not leak.

Conventionally, in order to seal the injection port of this type of liquid crystal display element, a method with good workability is disclosed in Japanese Patent Application Laid-Open No. 54-15365.
No. 1, JP-A-57-138618, etc., a composition (sealing material) of an acrylic radical polymerization type photocurable resin is directly attached to an injection port and irradiated with ultraviolet light. A method of curing and fixing the above composition has been adopted.

However, this method has a serious problem that the alignment film of the liquid crystal display element receiving the ultraviolet light near the injection port is damaged and the alignment characteristics of the liquid crystal are impaired.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel method for manufacturing a highly reliable liquid crystal display device which has good workability and has good alignment characteristics of liquid crystal and which is manufactured without damaging the alignment film. Is to provide.

[0007]

Means for Solving the Problems To solve the above problems, the inventor of the present invention provided an acrylic and / or ene / thiol radical polymerization type photocurable resin composition (sealing material) at an injection port. Coating, irradiating the composition with light having a wavelength of 350 nm to 500 nm, or blocking the alignment film surface with a mask material, irradiating ultraviolet light without wavelength limitation, curing the composition, and setting an injection port. By sealing, a liquid crystal display element satisfying the above-mentioned problem was obtained, and the present invention was achieved. In order to further increase the adhesiveness of the inlet seal, an adhesion promoter is added to the composition.

As the light source used in the present invention, a mercury lamp, a xenon lamp, a metal halide lamp or the like which generates a large amount of visible light and ultraviolet light having a wavelength of 500 nm or less is useful.
The light rays generated from these light sources may unnecessarily heat the liquid crystal display element or cause light deterioration of the liquid crystal. At the time of photo-curing of the above composition, a device is devised so that a light beam hits only the composition. The irradiation time is generally between 0.1 and 3 minutes.

Here, the wavelength of the light from the light source is 350 n
The light having a wavelength of 350 nm to 500 nm is preferable because the alignment film is damaged by short wavelength light of m or less and the curing reaction is slow and unproductive with long wavelength light of 500 nm or more. As an irradiation method, ultraviolet light is irradiated through a cut filter (for cutting light having a wavelength of 350 nm or less). When light is blocked by a mask material such as a metal plate coated with black on the alignment film surface to cure the composition and seal the injection port, ultraviolet light can be used directly without passing through a cut filter.

The composition of the acrylic radical polymerization type photocurable resin used in the present invention is based on a (meth) acrylic resin to which a photosensitizer has been added, and if necessary, the properties of the composition are improved. For the purpose of (1), an adhesion promoter (such as a silane coupling agent), a filler, and the like are added.

The (meth) acrylic resin is not particularly limited as long as it contains at least one (meth) acrylic group in one molecule and is cured at a high speed by radical polymerization.

However, the molecular skeleton of the (meth) acrylic resin is preferably polyester, polyether, hydrocarbon, silicone, or the like in order to improve the moisture proof property, adhesive property, incompatibility with liquid crystal, and the like.

The (meth) acrylic resin is a resin having a (meth) acrylic group attached to both ends of a molecular skeleton, for example, a polyester obtained from adipic acid and ethylene glycol, polyethylene glycol, bisphenol A diglycidyl ether, poly 1 , 2 butadiene, di (meth) acrylate such as polydimethylsiloxane, hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, and the like.

For the purpose of lowering the viscosity and adjusting the glass transition temperature, a (meth) acryl compound containing one (meth) acryl group in one molecule, for example, 2-ethylhexyl (meth) acrylate, 2-hydroxypropyl (Meth) acrylate, lauryl (meth) acrylate, decyl (meth) acrylate, benzyl (meth) acrylate, or the like may be used.

The photosensitizer used in the present invention is not particularly limited as long as it causes photolysis or hydrogen abstraction reaction by light having a wavelength in the visible to ultraviolet range to generate radicals and initiate radical polymerization by (meth) acrylic groups. There is no.

Examples of the photosensitizer include benzoin ethers such as benzoin isopropyl ether;
Acetophenones such as 2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin, benzophenones such as p-methoxybenzophenone, and thioxanthone Xanthones, m-chloroacetone, propiophenone, benzyl, anthraquinones such as 2-methylanthraquinone, benzyldimethyl ketal, and the like are useful. The amount of photosensitizer used is (meth) acrylic resin 100
0.01 to 5 parts by weight based on parts by weight is preferred.

The adhesion promoter improves the adhesive properties of the resin composition according to the present invention. In addition to the silane coupling agent and the titanium coupling agent, polychloroprene, poly-1,4-butadiene, Examples include styrene / butadiene copolymer, acrylonitrile / styrene / butadiene copolymer, and graft copolymers of rubbers such as ethylene / propylene rubber and (meth) acrylic resin. The amount of adhesion promoter used is (meth) acrylic resin 10
0.1 to 10 parts by weight is preferable with respect to 0 parts by weight.

As the filler, silica, alumina, calcium carbonate or the like can be used to improve the coating properties of the resin composition of the present invention, adjust the coefficient of thermal expansion and the like, and prevent solubility in liquid crystals.

The ene / thiol radical polymerization type photocurable resin composition used in the present invention is basically composed of a polyene compound and a polythiol compound with a photosensitizer added thereto. For the purpose of improvement, an adhesion promoter (such as a silane coupling agent) and a filler are added.

The polyene compound contains two or more carbon-carbon unsaturated double bonds (C ＝ C) in one molecule, and the polythiol compound also contains two or more mercapto groups (—SH) in one molecule. There is no particular limitation on both compounds as long as both are cured at a high rate by radical polymerization.

Examples of polyene compounds include divinylbenzene, divinyltoluene, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane, trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, pentaerythritol diallyl ether, pentaerythritol triaryl Allyl ether, pentaerythritol tetraallyl ether,
Ethylene glycol di (meth) allyl ether, propylene glycol di (meth) allyl ether, butylene glycol di (meth) allyl ether, polyethylene glycol di (meth) allyl ether, polypropylene glycol di (meth) allyl ether, polybutylene glycol di ( (Meth) allyl ether, di (meth) allyl ether of glycol which is a block or random copolymer of ethylene oxide and propylene oxide, di (meth) allyl ether of glycol which is a block of ethylene oxide and tetrahydrofuran or glycol which is a random copolymer, diphenol of bisphenol A (Meth) allyl ether,
Examples thereof include, but are not limited to, di (meth) allyl ether of (poly) ethylene oxide-modified bisphenol A and di (meth) allyl ether of (poly) propylene oxide-modified bisphenol A. Further, a mixture of two or more of these may be used.

Examples of the polythiol compound include diglycol dimercaptan, triglycol dimercaptan, tetraglycol dimercaptan, thiodiglycol dimercaptan, thiotriglycol dimercaptan, thiotetraglycol dimercaptan, bisphenol A type epoxide, Various polythiols obtained by reacting a general polyepoxide such as ethylene glycol diglycidyl ether with an excess of polythiol can be mentioned.
It is not limited to these.

Also, a mixture of two or more of these may be used.

The compounding ratio of the polyene compound and the polythiol compound used in the composition of the present invention is determined based on the carbon-
It is determined by the molar ratio of the carbon unsaturated double bond to the mercapto group of the polythiol, the ratio being 1: 1.5-1.5: 1, preferably 1: 1.2-1.2: 1, most preferably Is approximately 1: 1. If the ratio is out of the range, there may be a problem that an unpleasant smell is generated after curing, or the hardness of the cured product is too low, and if the hardness is extremely high, the cured product is not cured.

The photosensitizer used in the present invention may be one used in an acrylic radical polymerization type photocurable resin composition. The amount of the photosensitizer is 0 to 100 parts by weight of the total of the polyene compound and the polythiol compound. 0.01 to 5 parts by weight is preferred.

The adhesion promoter for improving the adhesive properties of the resin composition may be the same as that used for the acrylic radical polymerization type photocurable resin composition, and may be a silane coupling agent or a titanium coupling agent. In addition to agents, graft copolymers of rubbers such as polychloroprene, poly-1,4-butadiene, styrene-butadiene copolymer, acrylonitrile-styrene-butadiene copolymer, ethylene-propylene rubber, and (meth) acrylic resin There are polymers and the like. The amount of the adhesion promoter used is 0.1 to 10 based on 100 parts by weight of the total of the polyene compound and the polythiol compound.
Parts by weight are preferred.

Fillers are also used to improve the coating properties of the resin composition, adjust the coefficient of thermal expansion, etc., and prevent solubility in liquid crystals.
It may be the same as that used for the composition of the acrylic radical polymerization type photocurable resin, and silica, alumina, calcium carbonate and the like can be used.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Table 1 shows the composition and composition No. of the photocurable resin composition (sealing material) used for sealing the injection port.

[0030]

[Table 1]

Here, compositions No. 1 to No. 5 are acrylic radical polymerization type photocurable resin compositions, and compositions No. 6 to No.
No. 11 shows an ene / thiol radical polymerization type photocurable resin composition, respectively.

In the liquid crystal display device shown in FIG. 1, after injecting the liquid crystal, the liquid crystal attached around the injection port was wiped off, and immediately, a resin composition was applied to the injection port.

As shown in FIGS. 2 and 3, the applied resin composition as the sealing material 7 is photo-cured, and the liquid crystal display element 8 is cured.
Was sealed.

That is, FIG. 2 shows a wavelength 350n of the present invention.
As a cut filter 9 for cutting light of m or less, a colored glass filter UV-35 (manufactured by Toshiba Glass Co., Ltd.) is used. The method of photocuring is shown. FIG.
As a mask material 11 of the present invention, a black aluminum metal plate having a thickness of about 1 mm is used, the alignment film surface is light-blocked, and the light from the light source 10 of the high-pressure mercury lamp is entirely irradiated without wavelength limitation. 2 shows a method for photocuring the composition of Example 1.

Liquid crystal display element 8 obtained by light curing sealing
FIG. 4 shows a method for evaluating the alignment characteristics of the alignment film 1 described above.

That is, the polarizing directions of the two polarizing plates 12 are made orthogonal to each other, the liquid crystal display element 8 is sandwiched between them, one side faces the direction of the light 13, and the other is viewed with the eyes 14 from the other side.

When the light looks uniform, the liquid crystal display element 8
Shows that the alignment film 1 is not damaged and the alignment characteristics are good.

On the other hand, when the light looks non-uniform, it indicates that the alignment film 1 is damaged and the alignment characteristics are poor.

As another characteristic, adhesiveness was determined. The presence or absence of peeling of the sealing material is visually observed, and a liquid crystal display element in which peeling is not observed has good adhesiveness, and one in which peeling is visible indicates poor adhesiveness.

In addition, the alignment characteristics and adhesiveness of the liquid crystal display element were determined not only in the initial stage but also in a high temperature storage test (60 ° C., 1
000 hours) and a high-temperature and high-humidity test (70 ° C., 95% RH, 500 hours).

Using the photocurable resin composition (encapsulant) having the composition shown in Table 1, the characteristics of the liquid crystal display device were examined by changing the curing conditions. The results are shown in Table 2.

[0042]

[Table 2]

Here, for example, Example No. 1 is No.
Five types of resin compositions from No. 1 to No. 5 were separately provided with a cut filter and light irradiation conditions of 100 mW / cm ² (wavelength 365 nm)
All the five types of liquid crystal display devices manufactured in × 70 seconds are shown, and the characteristics of Example No. 1 in Table 2 are marked with “○”, which means that the characteristics of all the five types of liquid crystal display devices are good. It is shown.

From Table 2, it is found that Examples Nos. 1 to 6 have the initial alignment characteristics and adhesiveness of the liquid crystal display element regardless of the light irradiation conditions because the cut filter or the mask material of the present invention is provided at the time of photocuring. It turns out that both are good after the reliability test.

On the other hand, Comparative Examples Nos. 7 to 12 had good adhesion of the liquid crystal display element because neither the cut filter nor the mask material of the present invention was used at the time of photocuring, but had poor alignment characteristics from the beginning. It can be seen that it is.

Further study was carried out and the results of Example No.
It became clear that the liquid crystal display elements of Nos. 1 to 6 were all good at the initial stage and after the reliability test, as well as other necessary characteristics such as electric characteristics.

[0047]

The liquid crystal display device manufactured according to the present invention has the following features.
The alignment layer, which has been regarded as a disadvantage of the prior art regarding the sealing of the liquid crystal injection port, is no longer damaged, and the important function of alignment characteristics has been greatly improved.

By applying this, a low-cost and highly reliable liquid crystal display device can be manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a liquid crystal display device of the present invention.

FIG. 2 is an explanatory view of a method for curing a resin composition according to the present invention.

FIG. 3 is a view showing a method for curing a resin composition according to the present invention.

FIG. 4 is a diagram showing a method for evaluating the alignment characteristics of the liquid crystal display device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Orientation film, 2 ... Electrode board, 3 ... Spacer, 4 ... Sealing material, 5 ... Liquid crystal, 6 ... Injection port, 7 ... Sealing material, 8 ... Liquid crystal display element, 9 ... Cut filter, 10 ... Light source, 11 ... Mask materials, 12 ... Polarizers, 13 ... Light, 14 ... Eyes.

Claims (14)

[Claims] 1. A liquid crystal display device comprising two electrode substrates with an alignment film, after injecting liquid crystal, applying an acrylic radical polymerization type photocurable resin composition to the injection port to obtain a liquid crystal having a wavelength of 350 nm.
curing the composition by irradiating light of 500 nm to 500 nm,
A method for manufacturing a liquid crystal display element, characterized by sealing an inlet. 2. A liquid crystal display device comprising two electrode substrates with an alignment film, after injecting a liquid crystal, applying a composition of an acrylic radical polymerization type photocurable resin to the injection port, and masking the alignment film surface with a mask material. Wherein the composition is cured by irradiating ultraviolet light with ultraviolet light, and the injection port is sealed. 3. A liquid crystal display device comprising two electrode substrates with an alignment film, after injecting liquid crystal, applying an acrylic radical polymerization type photocurable resin composition to the injection port, and passing ultraviolet light through a cut filter. A method for manufacturing a liquid crystal display element, comprising irradiating light to cure the composition and sealing an injection port. 4. A liquid crystal display device comprising two electrode substrates with an alignment film, after injecting a liquid crystal, applying an ene / thiol radical polymerization type photocurable resin composition to the injection port,
A method for producing a liquid crystal display element, comprising irradiating light of 350 nm to 500 nm to cure the composition and sealing an injection port. 5. A liquid crystal display device comprising two electrode substrates with an alignment film, after injecting liquid crystal, applying an acrylic and ene / thiol mixed radical polymerization type photocurable resin composition to the injection port. A method for manufacturing a liquid crystal display element, comprising irradiating light having a wavelength of 350 nm to 500 nm to cure the composition and sealing an injection port. 6. A liquid crystal display element comprising two electrode substrates with an alignment film, after injecting liquid crystal, applying an acrylic radical polymerization type photocurable resin composition containing an adhesion promoter to the injection port, A method for manufacturing a liquid crystal display element, comprising irradiating light having a wavelength of 350 nm to 500 nm to cure the composition and sealing an injection port. 7. In a liquid crystal display element comprising two electrode substrates with an alignment film, after injecting liquid crystal, an injection port is coated with an ene / thiol radical polymerization type photocurable resin composition containing an adhesion promoter. A method for manufacturing a liquid crystal display device, comprising irradiating light having a wavelength of 350 nm to 500 nm to cure the composition and sealing an injection port. 8. A liquid crystal display element comprising two electrode substrates with an alignment film, wherein after injecting liquid crystal, an acrylic and ene / thiol mixed radical polymerization type photocurable resin in which an adhesion promoter is blended into the injection port. Apply the composition, wavelength 350nm ~ 5
A method for manufacturing a liquid crystal display device, comprising irradiating light of 00 nm to cure the composition and sealing an injection port. 9. A liquid crystal display device comprising two electrode substrates with an alignment film, after injecting a liquid crystal, applying an ene / thiol radical polymerization type photocurable resin composition to the injection port, and applying a surface of the alignment film. A method for manufacturing a liquid crystal display element, comprising blocking light with a mask material, irradiating ultraviolet light to cure the composition, and sealing an injection port. 10. A liquid crystal display element comprising two electrode substrates with an alignment film, after injecting a liquid crystal, applying an acrylic and ene / thiol mixed radical polymerization type photocurable resin composition to the inlet. A method for manufacturing a liquid crystal display device, comprising: shielding the alignment film surface with a mask material, irradiating ultraviolet light to cure the composition, and sealing an injection port. 11. A liquid crystal display device comprising two electrode substrates with an alignment film, wherein after injecting liquid crystal, an acrylic and ene / thiol mixed radical polymerization type photo-curable resin in which an adhesion promoter is blended into the injection port. A method for producing a liquid crystal display device, comprising applying a composition, shielding the alignment film surface from light with a mask material, irradiating ultraviolet light to cure the composition, and sealing an injection port. 12. A liquid crystal display element comprising two electrode substrates with an alignment film, after injecting a liquid crystal, applying an ene / thiol radical polymerization type photocurable resin composition to the injection port, and passing through a cut filter. A method for producing a liquid crystal display element, comprising irradiating the composition with ultraviolet light to cure the composition and sealing an injection port. 13. A liquid crystal display device comprising an electrode substrate with two alignment films, after injecting liquid crystal, applying an acrylic and ene / thiol mixed radical polymerization type photocurable resin composition to the injection port, A method for producing a liquid crystal display device, comprising irradiating ultraviolet light through a cut filter to cure the composition and sealing an injection port. 14. A liquid crystal display device comprising two electrode substrates with an alignment film, wherein after injecting liquid crystal, an acrylic and ene / thiol mixed radical polymerization type photocurable resin in which an adhesion promoter is blended into the injection port. A method for applying a composition and irradiating ultraviolet light through a cut filter to cure the composition and sealing an injection port.