JPH0915614A - Liquid crystal display element and its production - Google Patents

Abstract

PURPOSE: To provide a liquid crystal display element having an excellent display grade and reliability by forming the curing rate of a curable resin to a specific value or above. CONSTITUTION: This liquid crystal display element consists of the structure obtd. by controlling the cell gap of two substrates 1a, 1b with electrodes subjected to orientation treatments by resin bead spacer materials 6 arranged at a specified density by spraying and adhering the two substrates 1a, 1b with the electrodes subjected to the orientation treatments by a sealant 4 and sealing liquid crystals 3 by the sealant 4. The element is provided with the transparent electrodes 2a, 2b formed on the main surfaces of the substrates 1a, 1b and polyimide oriented films 5a, 5b formed to cover the transparent electrodes 2a, 2b formed on the main surfaces of the substrates 1a, 1b. The polyimide oriented films 5a, 5b are formed so as not to overlap on the regions where the sealant 4 is formed. The sealant 4 is a thermosetting type sealant. Curing reaction is so effected that the curing rate of the thermosetting resin attains >=80%, by which the liquid crystal display element having good display characteristics, excellent mechanical strength and high reliability is obtd in the case such thermosetting type sealant 4 is used.

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 element used as a display device for various electronic devices and a method for manufacturing the same, and particularly to a liquid crystal display element having excellent reliability and capable of high-quality display. And a manufacturing method thereof.

[0002]

2. Description of the Related Art In a liquid crystal display device in which a liquid crystal is sealed between two transparent substrates with electrodes (hereinafter, simply referred to as substrates), the two substrates are bonded and the liquid crystal is sealed. As the sealing material for this purpose, generally, a resin composition containing a heat-curable curable resin, an ultraviolet curable resin, or a combination curable resin of ultraviolet curable and heat curable resin as its main component is used. ing. Of these, a resin composition containing a heat-curable curable resin as a main component (hereinafter referred to as a heat-curable sealing material) is often used, and the heat-curable curable resin is Mitsui Toatsu Chemical Co., Ltd. Made of struct bond (trade name) is famous. When the substrate is adhered and the liquid crystal is sealed with the heat-curable sealant, the sealant, that is, the curable resin is usually cured by placing the substrate coated with the sealant in a constant temperature bath for a predetermined time. Has been done.

On the other hand, recently, in order to improve work efficiency and yield, a resin composition containing a UV-curable curable resin as a main component as a sealing material (hereinafter referred to as an UV-curable sealing material). .), Or a resin composition containing a curable resin of a combination type of ultraviolet curing and heat curing as a main component (hereinafter, referred to as a combination sealant of ultraviolet curing and heat curing type) is also often used. ing. These UV-curable sealants or UV-curable and heat-curable combined sealants can accelerate the curing of the curable resin faster than the heat-curable sealants, and thus cause misalignment of the alignment after bonding the substrates. In addition to the advantage that it can be eliminated, it has the advantage that the sealing material has excellent linearity and that the sealing material has no orientation defect. The hardening of the curable resin in the ultraviolet-curable sealing material and the ultraviolet-curable and heat-curable sealing material is carried out by irradiating the portion for sealing the liquid crystal with ultraviolet light for a predetermined time.

[0004]

As described above, in the conventional process of manufacturing a liquid crystal display element, the heat-curing sealing material is heated and cured by placing the substrate on which the sealing material is placed in a constant temperature bath for a predetermined time. It is done by For this reason, for example, when a large number of substrates are put into the tank and the temperature in the tank varies, the curing reaction (polymerization reaction) of the curable resin does not proceed sufficiently, and as a result, the substrate is changed in each cell. In the separation and cutting step of separating, that is, in the step of separating and cutting the substrate into a plurality of panels each of which serves as an element cell, peeling of the sealing material occurs at the corners of the panel, and liquid crystal is injected into the cell. There is a problem that the uncured component of the sealing material is later eluted into the liquid crystal and the display quality of the obtained liquid crystal display element is deteriorated.

Further, when the sealing work is carried out by using the ultraviolet curable seal material, the adhesive strength is insufficient with the ultraviolet curable seal material alone. Therefore, the ultraviolet curable seal material is usually used on the side in contact with the liquid crystal, It has been practiced to adopt a double seal structure around which a heat-curable seal material or a combined ultraviolet-curable and heat-curable seal material is formed.
However, in this case, the illuminance decreases due to the life of the ultraviolet lamp, the amount of ultraviolet energy reaching the sealing material changes depending on the material of the substrate (glass, plastic film) and its thickness, and the color when using a substrate with a color filter. A sufficient curing reaction (polymerization reaction) of the sealing material may not be performed due to the absorption of ultraviolet rays by the filter, etc., and the uncured resin component is eluted into the liquid crystal, resulting in poor alignment or deterioration of electrical characteristics. There is a problem that the display quality of the element is deteriorated. In particular, when the ultraviolet curing resin is an epoxy resin, the curing speed is slow because the ultraviolet curing mechanism is cationic polymerization,
A large amount of UV irradiation energy is required to obtain sufficient polymerization, and the above problems appear more remarkably. When the ultraviolet curing mechanism is cationic polymerization, a cationic photoinitiator (for example, Irgacure 261 (trade name) manufactured by Nippon Ciba-Geigy Co., Ltd.) is used, so that the liquid crystal panel is left in high temperature and high humidity. In such a case, the cationic photoinitiator is eluted into the liquid crystal, which causes a problem that the reliability of the liquid crystal panel is significantly deteriorated.
Further, when the ultraviolet curing resin is an acrylate or methacrylate resin, the ultraviolet curing mechanism is radical polymerization, so that the polymerization rate is high and the display quality of the liquid crystal display element is deteriorated. It has the advantage of being less likely to occur and the effect of the photoinitiator on the liquid crystal being less, but problems such as lack of adhesiveness due to large curing shrinkage and high reaction rate cannot be obtained. I will end up. Note that in the case of a liquid crystal display element manufactured by a manufacturing process that includes a step of dropping liquid crystal between the steps of bonding the substrates, the liquid crystal and the uncured sealing material come into contact in the manufacturing process, and therefore, the sealing is performed in a short time. It is necessary to cure the material, and the use of UV-curable sealing material is an absolute requirement.

The present invention has been made to solve the above-mentioned problems, and it is possible to obtain a high-quality liquid crystal display in which the uncured component of the sealing material is not eluted into the liquid crystal, and moreover,
It is an object of the present invention to provide a high-quality and highly-reliable liquid crystal display device in which a sealing material is firmly adhered to a corner portion of a substrate (panel) and a manufacturing method capable of manufacturing the liquid crystal display device with good reproducibility.

[0007]

In a liquid crystal display device according to the present invention, two transparent substrates with electrodes are adhered by a resin composition containing a curable resin as a main component, and the two transparent substrates with electrodes are attached. A liquid crystal display device in which liquid crystal is sealed in a gap between substrates by the resin composition, wherein the curing rate of the curable resin is 80% or more.

In the above structure, it is preferable that the curing material for curing the curable resin contained in the resin composition is a radical polymerization initiator for initiating radical polymerization of the curable resin.

Next, in the method for manufacturing a liquid crystal display element according to the present invention, a curable resin and a curing material for starting the curing of the curable resin are provided on a portion to be sealed on the electrode mounting surface of the first transparent substrate with electrodes. After forming a sealing resin composition containing
The first and second transparent substrates with electrodes are obtained by bonding the electrode mounting surface of the second transparent substrate with electrodes to the electrode mounting surface of the first transparent substrate with electrodes, and curing the curable resin. And a step of disposing a liquid crystal in the gap between the bonded first and second transparent substrates with electrodes, wherein two transparent substrates with electrodes are bonded by the sealing resin composition, A method for producing a liquid crystal display device, wherein a liquid crystal display device is obtained in which the liquid crystal is sealed in the gap between the two transparent substrates with electrodes by the sealing resin composition, the process comprising curing the curable resin. The step of curing the curable resin until the curing rate becomes 80% or more.

In the above structure, the curing material in the sealing resin composition is an ultraviolet curing material that starts the curing of the curable resin by irradiation of ultraviolet rays and a heat curing that starts the curing of the curable resin by heating. A first step of curing the curable resin, wherein the step of curing the curable resin includes irradiating the sealing resin composition with ultraviolet rays to cure the curable resin until the curing rate becomes at least 60%. It is preferable to include a step and a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate thereof becomes 80% or more.

Further, in the above-mentioned constitution, the curing material in the sealing resin composition is an ultraviolet curing material which starts the curing of the curable resin by irradiation of ultraviolet rays, and a curing agent which starts the curing of the curable resin by heating. A solid particle thermosetting material is included, and the step of curing the curable resin includes irradiating the sealing resin composition with ultraviolet rays so that the curable resin has a curing rate of at least 50%. The first step of curing the resin composition for sealing to heat the curable resin after the first step to a curing rate of 80.
Preferably, the second step is to cure until the content becomes at least%.

Further, in the method for manufacturing a liquid crystal display element according to the present invention, a curable resin and a curing material for initiating curing of the curable resin are included in a portion to be sealed on the electrode mounting surface of the first transparent substrate with electrodes. After applying and forming the sealing resin composition, at least one of the electrode surface on the electrode arrangement surface of the first transparent substrate with electrodes and the electrode surface on the electrode arrangement surface of the second transparent substrate with electrodes prepared separately Liquid crystal is then placed on the electrodes, and then the electrode placement surfaces of these substrates are pasted together with the sealing resin composition interposed therebetween so that a predetermined gap is left therebetween, and then the sealing resin composition is placed. By curing the curable resin therein, two transparent substrates with electrodes are adhered by the resin composition for sealing, and the liquid crystal is sealed in the gap between the two transparent substrates with electrodes by the resin composition for sealing. Sealed In the method for producing a liquid crystal display element, the curing material in the resin composition for sealing is an ultraviolet curing material that starts curing of the curable resin by irradiation of ultraviolet rays, and A thermosetting material for initiating the curing of a curable resin, wherein the step of curing the curable resin is such that the curing resin has a curing rate of at least that of irradiating the sealing resin composition with ultraviolet rays. It consists of a first step of curing to 60% and a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate becomes 80% or more. It is characterized by that.

Further, in the method for manufacturing a liquid crystal display element according to the present invention, a curable resin and a curing material for initiating curing of the curable resin are included in a portion to be sealed on the electrode disposing surface of the first transparent substrate with electrodes. After applying and forming the sealing resin composition, at least one of the electrode surface on the electrode arrangement surface of the first transparent substrate with electrodes and the electrode surface on the electrode arrangement surface of the second transparent substrate with electrodes prepared separately Liquid crystal is then placed on the electrodes, and then the electrode placement surfaces of these substrates are pasted together with the sealing resin composition interposed therebetween so that a predetermined gap is left therebetween, and then the sealing resin composition is placed. By curing the curable resin therein, two transparent substrates with electrodes are adhered by the resin composition for sealing, and the liquid crystal is sealed in the gap between the two transparent substrates with electrodes by the resin composition for sealing. Sealed In the method for producing a liquid crystal display element, the curing material in the resin composition for sealing is an ultraviolet curing material that starts curing of the curable resin by irradiation of ultraviolet rays, and A thermosetting material in the form of solid particles for starting the curing of the curable resin is included, and the step of curing the curable resin is performed by irradiating the sealing resin composition with ultraviolet rays to cure the curable resin. A first step of curing until the curing rate reaches at least 50%, and a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate reaches 80% or more It is characterized by comprising steps.

In the above structure, a pair of large-area transparent substrates with electrodes is used, and the manufacturing process according to any one of the above-described manufacturing methods is performed, so that the pair of large-area transparent substrates with electrodes is formed into the transparent substrate with electrodes. By forming a plurality of liquid crystal display elements, and then dividing the pair of large-area transparent substrates with electrodes in which a plurality of liquid crystal display elements are formed into a plurality of pieces, the plurality of liquid crystal display elements are individually separated. It is preferably separated.

In the above constitution, it is preferable that the curable resin has a curing reaction which proceeds by radical polymerization.

[0016]

In the above-mentioned liquid crystal display device of the present invention, 2
A liquid crystal display device in which two transparent substrates with electrodes are adhered by a resin composition containing a curable resin as a main component, and liquid crystal is sealed in the gap between the two transparent substrates with electrodes by the resin composition. In addition, when the curing rate of the curable resin is 80% or more, there is no elution of the uncured component of the curable resin into the liquid crystal, it is possible to prevent deterioration of display quality, and the substrate ( The resin composition is firmly adhered also to the corner portion of the panel), and the mechanical strength of the device can be improved.

As a preferred example of the above-mentioned constitution, a curing material for curing the curable resin contained in the resin composition is
A radical polymerization intermediary agent that initiates radical polymerization of the curable resin is more preferable in preventing deterioration of display quality without elution of the curing material into the liquid crystal.

Next, in the above-described method for manufacturing a liquid crystal display element of the present invention, a curable resin and a curing agent for initiating curing of the curable resin are provided on a portion to be sealed on the electrode mounting surface of the first transparent substrate with electrodes. After forming a sealing resin composition containing a material, the electrode mounting surface of the second transparent substrate with an electrode is bonded to the electrode mounting surface of the first transparent substrate with an electrode to cure the curable resin. As a result, the first and second
And a step of arranging a liquid crystal in the gap between the adhered first and second transparent substrates with electrodes, wherein the two transparent substrates with electrodes have the sealing resin composition. A method for producing a liquid crystal display device, comprising: a liquid crystal display device, which is adhered by an object, and the liquid crystal is sealed in the gap between the two transparent substrates with electrodes by the sealing resin composition. The step of curing the resin is a step of curing the curable resin until the curing rate becomes 80% or more, so that the two transparent substrates with electrodes are firmly adhered, and the substrate ( The peeling of the sealing resin composition at the panel) corner portion is prevented, and a highly reliable liquid crystal display device can be manufactured with a high yield.

As a preferable example of the above-mentioned constitution, the curing material in the sealing resin composition is an ultraviolet curing material which starts the curing of the curable resin by irradiation of ultraviolet rays, and a curing of the curable resin is started by heating. And a step of curing the curable resin, in which the curable resin is irradiated with ultraviolet rays to cure the curable resin until the curing rate becomes at least 60%. It comprises a first step and a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate becomes 80% or more.
In the step of adhering the first and second transparent substrates with electrodes, the curable resin is cured at a high speed by irradiation with ultraviolet rays, so that the first and second transparent substrates with electrodes are misaligned in a short time. Adhesion without occurring, uncured components of the curable resin and elution of the thermosetting material to the liquid crystal are prevented, and further, the first and second transparent substrates with electrodes are formed by heat curing of the curable resin. Since they are firmly bonded, a liquid crystal display element having excellent display quality and high reliability can be manufactured with a high yield.

As a preferred example of the above-mentioned constitution, the curing material in the sealing resin composition is an ultraviolet curing material which starts the curing of the curable resin by irradiation of ultraviolet rays and a curing agent which cures the curable resin by heating. A solid particulate thermosetting material to be started, wherein the step of curing the curable resin includes irradiating the sealing resin composition with ultraviolet rays so that the curable resin has a curing rate of at least 50%. And a second step in which the sealing resin composition is heated after the first step to cure the curable resin until the curing rate becomes 80% or more. Then, in the step of adhering the first and second transparent substrates with electrodes, the curable resin is cured at a high speed by irradiation of ultraviolet rays, so that the first and second
The transparent substrate with an electrode is bonded in a short time without causing misalignment, and the elution of the uncured component of the curable resin into the liquid crystal and the thermosetting material is suppressed, and
Since the first and second transparent substrates with electrodes are firmly adhered by heat-curing the curable resin, a liquid crystal display element having excellent display quality and high reliability can be manufactured with high yield. You can Further, since the curing rate of the curable resin at the time of ultraviolet ray irradiation may be 50% or more, the ultraviolet ray irradiation time may be longer than that of the above-described method of making the curing rate of the curable resin at the ultraviolet ray irradiation 60% or more. The manufacturing time can be shortened.

Further, in the above-described method for manufacturing a liquid crystal display element of the present invention, a curable resin and a curing material for starting the curing of the curable resin are provided on the portion of the first electrode-equipped transparent substrate where the electrodes are to be sealed. Of the electrode surface on the electrode mounting surface of the transparent substrate with the first electrode and the electrode surface on the electrode mounting surface of the second transparent substrate with the electrode prepared separately. A liquid crystal is disposed on at least one side, and then the electrode disposition surfaces of these two substrates are bonded to each other with the sealing resin composition interposed therebetween so that a predetermined gap is formed therebetween, and then the sealing resin is used. The curable resin in the composition is cured so that two transparent substrates with electrodes are adhered by the resin composition for sealing, and the liquid crystal has the liquid crystal composition for sealing in the gap between the two transparent substrates with electrodes. By things A method for producing a liquid crystal display element, which comprises a liquid crystal display element sealed by means of: a curing material in the resin composition for sealing, an ultraviolet curing material which starts curing of the curable resin by irradiation with ultraviolet rays. A thermosetting material that starts the curing of the curable resin by heating, and a step of curing the curable resin, irradiating the sealing resin composition with ultraviolet rays to cure the curable resin. Of at least 60%, and a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate becomes 80% or more. By consisting of
In the first step, the curable resin is cured at a high speed, and the first and second transparent substrates with electrodes are bonded in a short time without misalignment, and the curing rate at this time is By setting at least 60%,
Elution of the uncured component in the curable resin and the thermosetting material into the liquid crystal is prevented. In addition, in the second step, the uncured component that cannot be cured in the first step is cured, and the curing rate of the curable resin is increased to 80% or more. Therefore, the transparent electrode with the first and second electrodes is transparent. The substrate is firmly adhered. Therefore, the uncured component of the curable resin does not elute into the liquid crystal, high-quality display can be performed, and the resin composition does not peel off at the corners of the substrate (panel) and has high mechanical strength. It is possible to manufacture a liquid crystal display device having the above with a high yield.

Further, in the above-described method for manufacturing a liquid crystal display element of the present invention, a curable resin and a curing material for starting the curing of the resin are provided on a portion to be sealed on the electrode-disposed surface of the first transparent substrate with electrodes. Of the electrode surface on the electrode mounting surface of the transparent substrate with the first electrode and the electrode surface on the electrode mounting surface of the second transparent substrate with the electrode prepared separately. A liquid crystal is disposed on at least one side, and then the electrode disposition surfaces of these two substrates are bonded to each other with the sealing resin composition interposed therebetween so that a predetermined gap is formed therebetween, and then the sealing resin is used. The curable resin in the composition is cured so that two transparent substrates with electrodes are adhered by the resin composition for sealing, and the liquid crystal has the liquid crystal composition for sealing in the gap between the two transparent substrates with electrodes. By things A method for producing a liquid crystal display element, which comprises a liquid crystal display element sealed by means of: a curing material in the resin composition for sealing, an ultraviolet curing material which starts curing of the curable resin by irradiation with ultraviolet rays. A solid particle thermosetting material that starts the curing of the curable resin by heating, and the step of curing the curable resin,
A first step of irradiating the sealing resin composition with ultraviolet rays to cure the curable resin until the curing rate becomes at least 50%, and heating the sealing resin composition after the first step. By including the second step of curing the curable resin until the curing rate becomes 80% or more, in the first step, the curable resin is cured at a high speed, and the first and Since the transparent substrate with the second electrode is bonded in a short time without causing misalignment and the curing rate at this time is at least 50%, the uncured component in the curable resin and the thermosetting resin are cured. The elution of the material into the liquid crystal is prevented. In addition, in the second step, the uncured component that cannot be cured in the first step is cured, and the curing rate of the curable resin is increased to 80% or more. Therefore, the transparent electrode with the first and second electrodes is transparent. The substrate is firmly adhered. Therefore, leaching of the uncured component of the curable resin and the thermosetting material into the liquid crystal is small, high-quality display can be performed, and there is no peeling of the resin composition at the corners of the substrate (panel). A liquid crystal display device having high mechanical strength can be manufactured with high yield. Further, since the curing rate of the curable resin at the time of ultraviolet ray irradiation may be 50% or more, the ultraviolet ray irradiation time may be longer than that of the above-described method of making the curing rate of the curable resin at the ultraviolet ray irradiation 60% or more. The manufacturing time can be shortened.

As a preferred example of the above structure, a pair of large-area transparent substrates with electrodes are used, and the manufacturing process according to any one of the above-mentioned manufacturing methods is performed to obtain the pair of large-area transparent electrodes. A plurality of the liquid crystal display elements are formed on a substrate, and thereafter, a pair of large-area transparent substrates with electrodes on which the plurality of liquid crystal display elements are formed are divided into a plurality of the liquid crystal display elements. Separation into individual units allows a plurality of liquid crystal display elements to be manufactured at one time, which improves manufacturing efficiency.

As a preferred example of the above-mentioned constitution, when the hardening reaction of the hardening resin proceeds by radical polymerization, the hardening speed of the hardening resin in the first step can be made higher, and the manufacturing time can be increased. Can be shortened.

[0025]

EXAMPLES As the curable resin used in the present invention, a heat curable curable resin or a combined curable resin of ultraviolet curing and heat curing is used. As the heat-curable curable resin, an epoxy-based resin, an acrylate-based resin, or a methacrylate-based resin can be used. A specific example of the epoxy resin is Epicoat (trade name) series manufactured by Yuka Shell Epoxy Co., Ltd. Specific examples of the acrylate resin (oligomer) include SP-1519 and SP-1563 (both are trade names) manufactured by Showa High Polymer Co., Ltd. As the thermosetting material, various curing materials such as aromatic amine-based, imidazole-based, acid anhydride-based, and hydrazide-based can be used for any of epoxy-based resin, acrylate-based resin, and methacrylate-based resin. Specific examples of the aromatic amine-based curing material include Epicure Z and Epicure 150 (both are trade names) manufactured by Yuka Shell Epoxy Co., Ltd. Specific examples of the imidazole-based curing material include Epicure EMI-24 manufactured by Yuka Shell Epoxy Co., Ltd.
(Product name). Specific examples of the acid anhydride-based curing material include Epicure YH-306 (trade name) manufactured by Yuka Shell Epoxy Co., Ltd. Specific examples of the hydrazide-based curing material include LDH, UDH, VDH (all are trade names) manufactured by Ajinomoto Co., Inc.
And the like. Further, regarding the acrylate-based resin and the methacrylate-based resin, an organic peroxide-based curing material can also be used, and specific examples thereof include Perbutyl O, Perbutyl 355, Perbutyl L, Perbutyl Z manufactured by NOF CORPORATION. , Perbutyl IF (both are trade names) and the like.

In the present invention, the two transparent substrates with electrodes are formed by using a curable resin and a resin composition (sealing material) whose main component is a curable material thereof to form a gap between the two substrates. In the liquid crystal display element manufactured by injecting and placing liquid crystal in this gap after bonding as described above, the resin composition (sealing material) uses a thermosetting curable resin as the curable resin, Both of those which use a curable resin of a combination of ultraviolet curing and heat curing can be used as the polymerizable resin. On the other hand, two transparent substrates with electrodes are used, and a resin composition containing a curable resin and a curing material thereof as a main component, that is, a coating film of a sealing material is formed on one of the transparent substrates with electrodes. In the liquid crystal display device produced by dropping the liquid crystal on the coating film, then bonding the other substrate to the coating film, and curing the curable resin, the resin composition (sealing material) is cured. It is necessary to use a curable resin that uses a combination of ultraviolet curing and heat curing as the curable resin. This is because when the uncured curable resin comes into contact with the liquid crystal for a long time, it elutes into the liquid crystal, so the ultraviolet curable cures the curable resin around the liquid crystal at an early stage and then heat-cures it. This is because the curable resin is cured until the curing rate reaches a level at which the curing rate at which the two transparent substrates with electrodes are firmly adhered, that is, 80% or more. At this time, if the curable resin is cured by UV curing so that the curing rate is at least 60%,
The presence of the curable component can surely prevent elution of the uncured component into the liquid crystal. At this time, as the curable resin of the combination type of ultraviolet curing and heat curing, an acrylate-based resin or a methacrylate-based resin whose curing proceeds by radical polymerization is preferably used. This is because when an epoxy resin is used, a cationic initiator is used as an ultraviolet curing material, so that when the resin composition (sealing material) before curing contacts the liquid crystal, This is because the cationic initiator in the material (sealing material) may be eluted into the liquid crystal, which may deteriorate the display quality of the liquid crystal display element. Specific examples of the acrylate-based or methacrylate-based resin include SP-1519 and SP-1563 (both are trade names) manufactured by Showa High Polymer Co., Ltd. described above, and acetophenone as an ultraviolet curing material. -Based, benzoin-based radical polymerization initiators are used, and specific examples include acetophenone-based ones such as Irgacure 907 (trade name) manufactured by Ciba-Geigy Co., Ltd. Japan, and benzoin-based ones. Irgacure 651 (trade name) manufactured by Ciba-Geigy Co., Ltd. can be mentioned.

Hereinafter, a liquid crystal display device according to an embodiment of the present invention and a method of manufacturing the same will be described in detail with reference to tables and drawings. (Specific Embodiment 1) FIG. 1 is a sectional view showing the device structure of a liquid crystal display device according to a specific embodiment 1 of the present invention. In the liquid crystal display element of this embodiment, the two electrode-attached substrates 1a and 1b that have been subjected to the alignment treatment are dispersed to arrange the resin bead spacer material 6 at a constant density to control the cell gap, and the sealing material 4 causes the alignment. It has a structure in which the two treated substrates with electrodes 1a and 1b are adhered and the liquid crystal 3 is sealed by a sealing material 4. In the figure, 2a and 2b are substrate 1
Transparent electrodes 5a and 5b formed on the main surfaces of a and 1b are polyimide alignment films formed on the main surfaces of the substrates 1a and 1b so as to cover the transparent electrodes 2a and 2b. The polyimide alignment films 5a and 5b are It does not overlap with the formation area of the sealing material 4. Here, the seal material 4 is a heat-curable seal material, that is, a resin composition containing a heat-curable curable resin and a thermosetting material, which is a curable material thereof, as main components.

In the following, a liquid crystal display element having the above structure was produced by changing the curing conditions of the heat-curable curable resin in the seal material 4, and the curing rate of the curable resin in the seal material 4 and the liquid crystal display element. It is the result of investigating the relationship of the device characteristics of. Table 1 shows the components of the heat-curable sealing material, and Table 2
Is a heat-curable resin in a heat-curable seal (epoxy resin: manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat 8
It shows the relationship between the curing rate of No. 07 (trade name) and the curing conditions (time, temperature). The curing rate here is the amount of change in the epoxy group before and after the curing reaction, FT-
It was obtained by measuring by IR, that is, the ratio of the reacted epoxy groups to the epoxy groups of the entire cured resin. Table 3 shows the display characteristics (appearance) of the liquid crystal panel, Table 4 shows the current value at 1 V / 100 Hz, and Table 5,
6 indicates the adhesiveness of the sealing material. In addition, Tables 5 and 6 show immediately after the completion of the curing reaction of the sealing material and at 120 ° C.
The peel strengths after and after performing the pressure cocker test for 8 hours at 0% and 2 atm are respectively shown, and these are measured by the test method shown in FIGS. FIG. 2 is a view of the state in which the peel strength test is being performed, viewed from the front side of the testing machine, and FIG. 3 is a view of the side of the testing machine viewed from the side. In these figures, 21 is a pressure measuring scale,
Reference numeral 22 is a pressing rod, 23 is a liquid crystal panel holding plate, 24 is a measurement liquid crystal panel (liquid crystal display element) including an upper substrate 24a and a lower substrate 24b, 25 is a liquid crystal panel support, 26 is a work table, and 27 is a pulse. It is a motor. The line width of the sealing material 4 in the liquid crystal panel for measurement manufactured this time is 1 mm. That is, the measuring liquid crystal panel 24 fixed on the workbench 26 rises when the workbench 26 is raised by the pulse motor 27, and at this time, the lower substrate 24
b is pressed by the pressing rod 22. Then, the pressing force when the lower substrate 24b is peeled from the upper substrate 24a is measured by the pressure measuring scale 21, and this pressing force becomes the peel strength.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

[0033]

[Table 5]

[0034]

[Table 6]

The current values in Table 4 correspond to the degree of liquid crystal composition unevenness and orientation unevenness between the substrates, and the current value is 3.0.
When it is less than μA, the degree of the unevenness is small, which means that it is a good product. Further, in Tables 5 and 6, when the peeling strength is 4.0 kg or more both after the curing reaction and after the pressure cocker test, it is judged as a good product.

As can be seen from the results of Tables 2 to 6, the liquid crystal panel (liquid crystal display device) obtained when the curing reaction was carried out so that the reaction ratio of the epoxy groups was 80% or more, the appearance evaluation, the current value, It can be seen that there is no problem in all characteristics such as adhesiveness and the product is a good product. Therefore, according to the present specific example, when the heat-curable sealing material is used, if the curing reaction of the heat-curable resin is performed so that the curing rate is 80% or more, good display characteristics and good mechanical strength can be obtained. It is clear that an excellent and highly reliable liquid crystal display device can be manufactured.

Specific Example 2 Hereinafter, a liquid crystal display element using a combination sealing material of ultraviolet curing and heat curing and a liquid crystal display element using an ultraviolet curing sealing material according to a specific example 2 of the present invention. Will be described. The structure of the element here is the same as that shown in the specific embodiment 2.
Tables 7 and 8 show the components of the UV-curable and heat-curable combined type sealant used in this example, and Table 9 shows the components of the UV-curable sealant. Table 10 shows a curable resin in the sealing material (Epoxy acrylate SP-1 manufactured by Showa High Polymer Co., Ltd.)
563 (trade name)) and the curing conditions (UV irradiation time) are shown. In the table, sealing material A has the components shown in Table 7, sealing material B has the components shown in Table 8, and seals. Material C has the components shown in Table 9. The curing rate here is obtained by measuring the amount of change in the carbon-carbon double bond portion (C = C) before and after the curing reaction by FT-IR, that is, the curing rate. C of entire resin =
It is the ratio of reacted C = C double bond to C double bond. Table 11 shows the display characteristics (appearance) of the liquid crystal panel, and Table 12 shows the current value at 1 V · 100 Hz. The UV lamp used for UV curing is a Japanese battery 〓
Made high pressure mercury lamp HGQ-2000 is used, and the ultraviolet illuminance of 420 nm or less irradiated to the sealing material is 20 mw.
I made it.

The criteria for the evaluation of the element characteristics here are the same as those in the concrete example 1.

[0039]

[Table 7]

[0040]

[Table 8]

[0041]

[Table 9]

[0042]

[Table 10]

[0043]

[Table 11]

[0044]

[Table 12]

From Tables 10 to 12, in all the sealing materials A (Table 7), B (Table 8) and C (Table 9), if the curing rate is set to 60% or more by UV curing, the liquid crystal display is surely performed. It can be seen that the display characteristics of the device are good. In particular, when the sealing material A (Table 7), which is a combination sealing material of ultraviolet curing and heat curing, is used, the thermosetting material contained therein (Epicure Z (trade name) manufactured by Yuka Shell Epoxy Co., Ltd.) Is a liquid aromatic amine, the thermosetting material easily elutes into the liquid crystal, and the curing rate of the curable resin is set to 60% or more so that the curability of the curable resin does not increase. It is necessary to prevent the curing component and the thermosetting material from eluting into the liquid crystal, but this is included when the sealing material B (Table 8), which is a combination sealing material of ultraviolet curing and heat curing, is used. Since the thermosetting material (hydrazine-based thermosetting material UDH manufactured by Ajinomoto Co., Inc.) is a solid particle hydrazide-based compound, the thermosetting material does not easily elute into the liquid crystal, and in this case, the thermosetting material is included. A seal that is a UV-curable sealant As in the case of using C, if the curing rate of the curable resin is 50% or more, the uncured component of the curable resin and the thermosetting material can be prevented from eluting into the liquid crystal, and the display characteristics Can be at a satisfactory level. Therefore, in the case where the illuminance of the ultraviolet irradiation lamp is the same, in the case of the combination type of the ultraviolet curing and the heat curing, the case where the thermosetting material is solid particles is more than the case where the thermosetting material is liquid. Thus, it can be seen that ultraviolet curing can be performed in a short time, and the efficiency of productivity can be improved. Table 13
The curability of each of the above three kinds of sealing materials A (Table 7), B (Table 8), and C (Table 9) was further cured under various heating conditions after the UV curing reaction was saturated. The relationship between the curing condition (heating condition) and the curing rate when the resin is cured by heating is shown. In addition, Tables 16 to 18 show the adhesive properties after heat curing. The curing rate here is the amount of change in the carbon-carbon double bond (C = C) before and after the curing reaction, which is the same as the above.
It was obtained by measuring in. The adhesive property is the peel strength obtained by the peel test shown in FIGS. 2 and 3 as in the specific example 1.

[0046]

[Table 13]

[0047]

[Table 14]

[0048]

[Table 15]

[0049]

[Table 16]

[0050]

[Table 17]

[0051]

[Table 18]

From these Tables 13 to 15 and Tables 16 to 18,
In the case of a combination type sealant of ultraviolet curing and heat curing, the curing rate of the curable resin is set to 8 by heat curing after ultraviolet curing.
Peel strength is 5k by curing to 0% or more
In the subsequent step of separating and cutting the substrate into cells, such that the substrate has a gf or more, sufficient adhesion to the substrate that does not cause substrate peeling can be provided. In contrast,
In the case of the ultraviolet curable sealant, the curing rate does not change even after heating, and the adhesiveness cannot be improved. Therefore, the adhesiveness between the substrate and the sealing material becomes insufficient only with the ultraviolet curable sealing material.

From the above results, using a combination type sealing material of ultraviolet curing and heat curing, first, the curing rate of the curable resin in the sealing material by ultraviolet curing is 60% or more (the thermosetting material is composed of solid particles. In this case, by curing the curable resin in the sealing material by heat curing so that the curing rate becomes 80% or more, excellent display characteristics can be obtained, and It can be seen that a display element having a high mechanical strength in which the substrates are firmly bonded can be obtained. In particular, the ultraviolet curing in the first stage has a high curing speed, and since the substrate is temporarily fixed without any misalignment, it is possible to prevent the occurrence of product defects due to misalignment and improve the manufacturing efficiency. .

(Specific Example 3) Next, a liquid crystal display element using a combination sealing material of ultraviolet curing and heat curing according to a specific Example 3 of the present invention will be described. In this specific example, a sealing material is applied and formed on a portion of the main surface of the electrode-equipped substrate that has been subjected to one of the orientation treatments, liquid crystal is dropped on the electrode surface, and the other electrode having the orientation treatment is applied. A spacer material is sprayed at a constant density on the main surface of the substrate, and the two main surfaces of the substrate with electrodes that have been subjected to these two orientation treatments are bonded to each other, and then the curable resin of the sealing material is UV-cured, and then the above-mentioned. A liquid crystal display element is manufactured by heating and curing the curable resin of the sealant. This will be described in more detail with reference to the drawings. As shown in FIG. 4, first, the principal surface of the electrode-equipped substrate 10a (the liquid molecular alignment film 11a A sealing material 12 is formed by screen printing on a portion of the surface) to be sealed, and then a liquid (not shown) is discharged onto the surface of the electrode (not shown) on the main surface of the electrode-attached substrate 10a (the surface of the liquid molecular alignment film 11a). The liquid crystal 13 is dropped using a device. Next, the remaining electrode-attached substrate 10 that has been subjected to an alignment treatment by the other liquid crystal molecular alignment film 11b made of polyimide
A spacer material 14 made of, for example, resin beads is arranged at a constant density on the main surface of b (the surface of the liquid molecular alignment film 11b). These 2 are then placed under a reduced pressure of 1 to 0.4 torr.
The main surfaces of the two substrates are bonded so as to face each other, and then the two substrates are pressed by utilizing the atmospheric pressure at the time of atmospheric pressure leak to form a constant cell gap to form a liquid crystal panel,
Subsequently, ultraviolet irradiation and substrate heating are performed in this order. Then, after this, the laminated substrate body obtained through the above steps is divided into a plurality of pieces to obtain a plurality of liquid crystal display elements. In this manufacturing method, since the liquid crystal and the uncured sealing material come into contact with each other, it is necessary to cure the curable resin of the sealing material immediately after the contact between the liquid crystal and the uncured sealing material. It is an absolute requirement to use a sealing material containing an ultraviolet curable resin that is cured by.

Table 19 shows the combination of the UV-curable and heat-curable sealing materials A and B used in the specific example 2, the ultraviolet lamp used in the specific example 2, and an ultraviolet illuminance of 20 mw. Shows the relationship between the curing conditions (irradiation time) and the display characteristics of the obtained element when the substrate was adhered by changing the irradiation time. Further, Table 20 shows the relationship between the curing conditions (irradiation time) and the current value of the obtained device at 1 V · 100 Hz.

[0056]

[Table 19]

[0057]

[Table 20]

Based on the results of Table 10 and Tables 19 and 20, in the same manner as the specific example 2, the specific type sealing material of the ultraviolet curing and the heat curing is used in the specific example as well. The curable resin in the sealing material is cured by curing so that the curing rate becomes 60% or more (50% or more when the thermosetting material is composed of solid particles), and then the curable resin in the sealing material is cured by heating. By curing so that the curing rate becomes 80% or more,
It can be seen that it is possible to obtain a liquid crystal display element which has excellent display characteristics and has a high mechanical strength in which the sealing material and the substrate are firmly fixed.

[0059]

As described above, according to the liquid crystal display element of the present invention, two transparent substrates with electrodes are adhered by a resin composition containing a curable resin as a main component, and
A liquid crystal display device in which a liquid crystal is sealed in the gap between the two transparent substrates with electrodes by the resin composition, and the curable resin has a curing rate of 80% or more, and thus has excellent display quality. There is an effect that a liquid crystal display element having reliability can be obtained.

Next, according to the method for manufacturing a liquid crystal display element of the present invention, a curable resin and a curing agent for initiating curing of the curable resin are provided on a portion to be sealed on the electrode mounting surface of the first electrode-attached transparent substrate. After forming a sealing resin composition containing a material, a second electrode is formed on the surface of the transparent substrate with an electrode.
And a step of adhering the first and second transparent substrates with electrodes by adhering the electrode disposition surfaces of the transparent substrate with electrodes to each other and curing the curable resin;
And placing a liquid crystal in the gap between the second electrode-attached transparent substrate, the two electrode-attached transparent substrates are adhered by the sealing resin composition, and the two electrodes-attached transparent substrate are placed in the gap. A method for producing a liquid crystal display device, wherein a liquid crystal is sealed with the sealing resin composition, comprising a step of curing the curable resin, wherein the curing rate of the curable resin is 80%. Since the curing process is performed until the above, the two transparent substrates with electrodes are firmly adhered to each other, and peeling of the resin composition at the corner portions of the substrates (panels) is prevented when the transparent substrates are separated. The advantage is that a highly reliable liquid crystal display element can be manufactured with a high yield.

Further, according to the method of manufacturing a liquid crystal display element of the present invention, a curable resin and a curing material for starting the curing of the resin are provided on a portion of the first electrode-equipped transparent substrate to be sealed on the surface where the electrodes are to be sealed. Of the electrode surface on the electrode mounting surface of the transparent substrate with the first electrode and the electrode surface on the electrode mounting surface of the second transparent substrate with the electrode prepared separately. A liquid crystal is disposed on at least one side, and then the electrode disposition surfaces of these two substrates are bonded to each other with the sealing resin composition interposed therebetween so that a predetermined gap is formed therebetween, and then the sealing resin is used. The curable resin in the composition is cured so that two transparent substrates with electrodes are adhered by the resin composition for sealing, and the liquid crystal has the liquid crystal composition for sealing in the gap between the two transparent substrates with electrodes. By things A method of manufacturing a liquid crystal display element, which comprises a liquid crystal display element that is stopped, wherein a curing material in the sealing resin composition is an ultraviolet curing material that starts curing of the curable resin by irradiation of ultraviolet rays, and heating. By including a thermosetting material to start the curing of the curable resin,
A step of curing the curable resin, a first step of irradiating the sealing resin composition with ultraviolet rays to cure the curable resin until the curing rate becomes at least 60%;
After the first step, the second step comprises heating the sealing resin composition to cure the curable resin until the curing rate becomes 80% or more. A liquid crystal display device having a high mechanical strength that does not elute an uncured component, can perform high-quality display, and has no peeling of the resin composition at a corner portion of a substrate (panel) with a high yield. There is an effect that can be manufactured.

Further, according to the method of manufacturing a liquid crystal display element of the present invention, a curable resin and a curing material for initiating the curing of the curable resin are provided on the portion of the first electrode-equipped transparent substrate where the electrodes are to be sealed. Of the electrode surface on the electrode mounting surface of the transparent substrate with the first electrode and the electrode surface on the electrode mounting surface of the second transparent substrate with the electrode prepared separately. A liquid crystal is disposed on at least one side, and then the electrode disposition surfaces of these two substrates are bonded to each other with the sealing resin composition interposed therebetween so that a predetermined gap is formed therebetween, and then the sealing resin is used. The curable resin in the composition is cured so that two transparent substrates with electrodes are adhered by the resin composition for sealing, and the liquid crystal has the liquid crystal composition for sealing in the gap between the two transparent substrates with electrodes. By things A method of manufacturing a liquid crystal display element, which comprises a liquid crystal display element that is stopped, wherein a curing material in the sealing resin composition is an ultraviolet curing material that starts curing of the curable resin by irradiation of ultraviolet rays, and heating. By including a solid particulate thermosetting material to start the curing of the curable resin, the step of curing the curable resin, irradiating the sealing resin composition with ultraviolet rays to the curable resin A first step of curing until the curing rate reaches at least 50%, and a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate reaches 80% or more Since it consists of a process, there is no elution of the uncured component of the curable resin into the liquid crystal, high-quality display can be performed, and the substrate (panel)
There is an effect that it is possible to manufacture a liquid crystal display device having a high mechanical strength and free from peeling of the resin composition at a corner with a high yield. In particular, since the curing rate of the curable resin at the time of ultraviolet ray irradiation may be 50% or more, the ultraviolet ray irradiation time may be longer than that of the above-described method of making the curing rate of the curable resin at the ultraviolet ray irradiation 60% or more. This has the effect of shortening the manufacturing time and shortening the manufacturing time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an element structure of a liquid crystal display element according to Example 1 of the present invention.

FIG. 2 is a diagram showing a state in which a peel strength test of a substrate of a liquid crystal display element (liquid crystal panel) is being performed, as viewed from the front side of the testing machine.

FIG. 3 is a diagram showing a state in which a peel strength test of a substrate of a liquid crystal display element (liquid crystal panel) is being performed, as viewed from a side surface side of a testing machine.

FIG. 4 is a cross-sectional view showing a main step in a manufacturing process of a liquid crystal display element according to a third specific example of the present invention.

[Explanation of symbols]

1a, 1b, 10a, 10b Aligned substrate with electrode 2a, 2b Transparent electrode 3, 13 Liquid crystal 4,12 Sealing material 5a, 5b, 11a, 11b Polyimide alignment film 6,14 Resin bead spacer material 21 For pressure measurement Scale 22 Pressing bar 23 Liquid crystal panel pressing plate 24 Liquid crystal panel for measurement 24a Upper substrate 24b Lower substrate 25 Liquid crystal panel support 26 Working table 27 Pulse motor

Claims (9)

[Claims] 1. Two transparent substrates with electrodes are bonded together by a resin composition containing a curable resin as a main component, and
A liquid crystal display device in which liquid crystal is sealed in a gap between a plurality of transparent substrates with electrodes by the resin composition, wherein the curable resin has a curing rate of 80% or more. 2. The liquid crystal display element according to claim 1, wherein the curing material that cures the curable resin contained in the resin composition is a radical polymerization initiator that initiates radical polymerization of the curable resin. 3. A sealing resin composition containing a curable resin and a curing agent for initiating the curing of the sealing resin composition is formed on a portion to be sealed on the electrode mounting surface of the first transparent substrate with electrodes, and No. 2 on the surface of the transparent substrate with electrode
And a step of adhering the first and second transparent substrates with electrodes by adhering the electrode disposition surfaces of the transparent substrate with electrodes to each other and curing the curable resin;
And placing a liquid crystal in the gap between the second electrode-attached transparent substrate, the two electrode-attached transparent substrates are adhered by the sealing resin composition, and the two electrodes-attached transparent substrate are placed in the gap. A method for producing a liquid crystal display element, wherein a liquid crystal display element is obtained in which liquid crystal is sealed with the resin composition for sealing, wherein the step of curing the curable resin has a curing rate of 80% for the curable resin. A method for manufacturing a liquid crystal display element, which is a step of curing until the above. 4. The curing material in the sealing resin composition,
An ultraviolet curable material that starts the curing of the curable resin by irradiation of ultraviolet rays, and a thermosetting material that starts the curing of the curable resin by heating, and the step of curing the curable resin is A first step of irradiating the sealing resin composition with ultraviolet rays to cure the curable resin until the curing rate becomes at least 60%;
The method for producing a liquid crystal display element according to claim 3, further comprising a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate becomes 80% or more. . 5. The curing material in the sealing resin composition is
An ultraviolet curable material that starts the curing of the curable resin by irradiation of ultraviolet rays, and a solid particulate thermosetting material that starts the curing of the curable resin by heating, and cures the curable resin. A first step of irradiating the sealing resin composition with ultraviolet rays to cure the curable resin until the curing rate becomes at least 50%;
The method for producing a liquid crystal display element according to claim 3, further comprising a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate becomes 80% or more. . 6. A sealing resin composition containing a curable resin and a curing agent for initiating curing of the sealing resin composition is applied and formed on a portion to be sealed of an electrode-disposed surface of a first transparent substrate with electrodes, Liquid crystal is arranged on at least one of the electrode surface on the electrode arrangement surface of the first electrode-equipped transparent substrate and the electrode surface on the electrode arrangement surface of the second electrode-equipped transparent substrate prepared separately. The electrode-disposed surface is pasted through the sealing resin composition so that a predetermined gap is left therebetween, and then the curable resin in the sealing resin composition is cured to A liquid crystal display in which a transparent substrate with electrodes is adhered by the resin composition for sealing, and the liquid crystal is sealed in the gap between the two transparent substrates with electrodes by the resin composition for sealing. How to manufacture the device In the method, the curing material in the sealing resin composition is an ultraviolet curing material that starts curing of the curable resin by irradiation of ultraviolet rays, and a thermosetting material that starts curing of the curable resin by heating. And a step of curing the curable resin, the first step of irradiating the sealing resin composition with ultraviolet rays to cure the curable resin until the curing rate becomes at least 60%,
A method of manufacturing a liquid crystal display element, comprising a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate becomes 80% or more. 7. A sealing resin composition containing a curable resin and a curing agent for initiating curing of the sealing resin composition is applied and formed on a portion of the first electrode-equipped transparent substrate on which the electrode is to be sealed, Liquid crystal is arranged on at least one of the electrode surface on the electrode arrangement surface of the first electrode-equipped transparent substrate and the electrode surface on the electrode arrangement surface of the second electrode-equipped transparent substrate prepared separately. The electrode-disposed surface is pasted through the sealing resin composition so that a predetermined gap is left therebetween, and then the curable resin in the sealing resin composition is cured to A liquid crystal display in which a transparent substrate with electrodes is adhered by the resin composition for sealing, and the liquid crystal is sealed in the gap between the two transparent substrates with electrodes by the resin composition for sealing. How to manufacture the device In the method, the curing material in the sealing resin composition is an ultraviolet curing material that starts the curing of the curable resin by irradiation of ultraviolet rays, and a solid particulate form that starts the curing of the curable resin by heating. A thermosetting material, wherein the step of curing the curable resin comprises irradiating the sealing resin composition with ultraviolet rays to cure the curable resin until the curing rate becomes at least 50%. 1 step,
A method of manufacturing a liquid crystal display element, comprising a second step of heating the sealing resin composition after the first step to cure the curable resin until the curing rate becomes 80% or more. 8. A pair of large-area transparent substrates with electrodes is obtained by using the pair of large-area transparent substrates with electrodes, and performing the process according to any one of claims 3, 6 and 7. By forming a plurality of the liquid crystal display elements, and then dividing the pair of large-area transparent substrates with electrodes into a plurality of liquid crystal display elements, the plurality of liquid crystal display elements are individually formed. A method for manufacturing a liquid crystal display element, which is separated into two parts. 9. The method for manufacturing a liquid crystal display element according to claim 3, wherein the curable resin has a curing reaction that proceeds by radical polymerization.