JPH112826A - Liquid crystal display element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the liquid crystal display element and its manufacture which protect a conductive member connecting two substrates electrically against contamination, etc., when a liquid crystal material, etc., entering the outside part of a seal between the two substrates is cleaned away and guarantee the reliability regarding the quality of the liquid crystal display element. SOLUTION: The liquid crystal display element has a liquid crystal layer 7 sandwiched between a couple of glass substrates 1a and 1b having transparent electrodes 2a and 2b respectively and has conductive members 4a and 4b which connect the two transparent electrodes 2a and 2b electrically; and a seal member 3c which seals the liquid crystal layer 7 and seal members 3a and 3b which surround the conductive members 4a and 4b are formed on the transparent electrode 2b provided to the glass substrate 1b at the same time by using screen printing, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used for a liquid crystal display device or an optical shutter, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Liquid crystal display elements are being put to practical use as large-screen, thin display devices in the field of information equipment mainly for portable personal computers and the field of video equipment mainly for televisions.

[0003] The prior art will be described below with reference to the drawings. FIG. 3 is a perspective view showing an exploded state of the liquid crystal display device for explaining the structure of the conventional liquid crystal display device.

[0004] As shown in FIG.
Are glass substrates 31a, 31b and transparent electrodes 32a, 3b.
2b, a sealing member 33, and conductive members 34a, 34b
, Opening 35, active element forming part 36, liquid crystal layer 37
It is composed of

The glass substrates 31a and 31b are transparent substrates made of glass and have transparent electrodes 32a and 32b which are conductive films made of ITO (thin film indium oxide). The seal member 33 is formed near the periphery of the glass substrates 31a and 31b. The opening 35 is a discontinuous portion provided in the seal member 33 for filling the liquid crystal layer 37 with liquid crystal. Liquid crystal is injected into the liquid crystal layer 37 from the opening 35.

The active element forming section 36 is an area where a TFT element is formed for each pixel of the liquid crystal display element 40 on the transparent electrode 32b. The conductive members 34a and 34b
It is a conductive paste applied on the transparent electrode 31b, and electrically connects the transparent electrode 32a and the transparent electrode 32b.

When injecting a liquid crystal material into a conventional liquid crystal display device having such a configuration, an empty liquid crystal display device in which the liquid crystal layer 37 is not filled with liquid crystal, that is, an empty cell is placed in a depressurized tank. Then, a vacuum injection method is generally used in which the inside of the cell is evacuated and then the liquid crystal material is injected into the cell by returning the inside of the tank to normal pressure while keeping the opening 35 in contact with the liquid crystal material. .

When the liquid crystal material is injected into the liquid crystal display element 40, the liquid crystal material is not only the liquid crystal layer 37 but also the glass substrate 3.
It also penetrates into the outer part of the seal member 33 between the first and second seals 32 (hereinafter referred to as the outside of the seal between the substrates). This phenomenon occurs due to the capillary phenomenon because the height of the sealing member 33, that is, the width between the glass substrates 31 and 32 is a small gap of several micrometers. Therefore, the opening 3
After sealing 5, the liquid crystal material that had entered the outside of the inter-substrate seal had to be washed and removed.

[0009]

However, in the above-mentioned conventional liquid crystal display element, if the liquid crystal that has entered the outside of the inter-substrate seal is washed away, the conductive members 34a and 34b may be contaminated or removed. In such a case, the impedance between the transparent electrodes 32a and 32b is significantly increased, and conduction is hindered, thereby deteriorating the quality of a displayed image.

The present invention solves the above-mentioned conventional problems, and protects the conductive members 34a and 34b when cleaning and removing liquid crystal that has entered the outside of the inter-substrate seal, thereby improving the reliability of the quality of the liquid crystal display element. It is an object of the present invention to provide a guaranteed liquid crystal display element and a method for manufacturing the same.

[0011]

In order to solve the above-mentioned problems, a liquid crystal display device according to a first aspect of the present invention has a pair of opposing substrates each having a voltage applying unit and at least one of which is transparent; A liquid crystal layer sandwiched between opposed substrates, a sealing member provided between the pair of opposed substrates and sealing the liquid crystal layer, and the voltage applying means provided on each of the pair of opposed substrates are electrically connected. It has a configuration including a conductive member to be connected and a protection member surrounding the conductive member.
According to the present invention, the conductive member can be protected from contamination and the like when the liquid crystal material or the like that has entered the outside of the inter-substrate seal is washed and removed.

According to a second aspect of the present invention, in the liquid crystal display element according to the first aspect, the seal resin, which is a material of the seal member and the protective member, is a thermosetting resin or a photocurable resin, or a thermosetting resin. It is characterized by being a curable and photocurable resin, or a resin obtained by mixing a thermosetting resin and a photocurable resin. According to the present invention, the protection member is formed using the same material as the seal member.

According to a third aspect of the present invention, in the liquid crystal display device according to the first or second aspect, the liquid crystal layer includes a polymer compound having a three-dimensional network structure and a polymer compound dispersed in the polymer compound. And a liquid crystal. According to the present invention, a polymer-dispersed liquid crystal display device having the effects of the first or second invention can be formed.

According to a fourth aspect of the present invention, in the liquid crystal display element according to the first aspect, the pair of opposed substrates is a transparent substrate having a voltage applying means provided with a transparent electrode.
According to the present invention, the effect of the first invention can be obtained in a transmission type polymer dispersed liquid crystal display element.

According to a fifth aspect of the present invention, in the liquid crystal display element according to the first aspect, at least one of the pair of opposing substrates is a transparent substrate, and the voltage applying means includes a transparent electrode provided on the transparent substrate. And the other substrate is provided with a reflective electrode. According to the present invention, the effects of the first invention can be obtained in a reflective liquid crystal display device.

A method for manufacturing a liquid crystal display device according to a sixth invention is the method for manufacturing a liquid crystal display device according to the second invention,
The protection member is formed using the sealing resin and the method of forming the sealing member in the step of forming the sealing member. According to the present invention, a protective member can be formed without a special process for forming a seal member.

A method for manufacturing a liquid crystal display device according to a seventh invention is the method for manufacturing a liquid crystal display device according to the sixth invention,
The method for forming the seal member is a screen printing method. According to the present invention, the protection member can be formed in the step of forming the seal member.

The method for manufacturing a liquid crystal display element according to the eighth invention is the method for manufacturing a liquid crystal display element according to the sixth invention,
The method for forming the seal member is a dispenser drawing method. According to the present invention, the protection member can be formed in the step of forming the seal member.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a state in which the liquid crystal display element is disassembled for explaining the structure of the liquid crystal display element of the present invention.

As shown in FIG. 1, the liquid crystal display element 10
Are glass substrates 1a and 1b, transparent electrodes 2a and 2b,
It comprises a seal member 3c, seal members 3a and 3b, conductive members 4a and 4b, an opening 5, an active element forming part 6, and a liquid crystal layer 7.

Glass substrates 11, 1 as a pair of opposed substrates
2 is a transparent substrate made of glass. The seal member 3c is formed near the periphery of the glass substrates 1a and 1b. The opening 5 is a discontinuous portion provided in the sealing member 3c for filling the liquid crystal layer 7 with liquid crystal. The liquid crystal layer 7 has a TN (twisted nematic) through the opening 5.
Liquid crystal is injected. Note that a plurality of openings 5 may be provided.

The transparent electrode 2a is a conductive film made of ITO provided on the glass substrate 1a, and is a transparent electrode common to all pixels of the liquid crystal display element 10. The transparent electrode 2b is a conductive film made of ITO provided on the glass substrate 1b.
The transparent electrode is divided for every 0 pixel.

The active element forming section 6 is an area on the transparent electrode 2b where a TFT element is formed for each pixel of the liquid crystal display element 10. Each TFT element in the active element forming section 6 is connected to each of the transparent electrodes 2b, and plays a role of a switch means for supplying a signal to be supplied to each of the transparent electrodes 2b from a drive circuit (not shown). In addition to the TFT element, an element that performs a similar switching function, for example, an MIM (Metal-Insulator-Metal) element may be used.

The conductive members 4a and 4b are conductive paste applied on the transparent electrode 1b, and electrically connect the transparent electrode 2a and the peripheral portion of the transparent electrode 2b. The sealing members 3a and 3b, which are protection members, are electrically conductive members 4a and 4b, respectively.
is formed on the transparent substrate 2b so as to surround the transparent substrate 2b. That is, the conductive member 4a is sealed by the transparent substrates 2a and 2b and the sealing member 3a, and the conductive member 4b is sealed by the transparent substrates 2a and 2b and the sealing member 3b. The transparent electrode 2a, the transparent electrode 2b, and the active element forming part 6 constitute a voltage applying means for applying a liquid crystal in the liquid crystal layer 7.

When a signal output from a drive circuit (not shown) is supplied to the liquid crystal display element 10 configured as described above, a voltage corresponding to the brightness of each pixel of an image to be displayed is changed. 7, and receives incident light from a backlight (not shown).
The image is displayed on.

Here, a specific material used for producing the liquid crystal display element 10 according to the present embodiment and a manufacturing method will be described.

The seal members 3a, 3b and 3c are formed by a screen printing method using a thermosetting resin as a resin (hereinafter referred to as a seal resin) as a material thereof.
FIG. 2 shows a screen printing plate 8 for forming the sealing members 3a, 3b, 3c. On the screen printing plate 8, there are provided permeation patterns 9a, 9b, 9c for forming the sealing members 3a, 3b, 3c, respectively.

The above-mentioned sealing resin is used as the penetration pattern 9a, 9
b, 9c, the transparent electrode 2b
A predetermined shape is formed thereon. When the sealing resin on the transparent electrode 2b is cured by heating at a temperature of 85 ° C. for 10 minutes, the sealing members 3a, 3b, and 3c are formed.

Instead of the thermosetting resin, it is also possible to use a photocurable resin which is cured by irradiating light such as ultraviolet rays as the sealing resin. Furthermore, it is a resin having the property of having both thermosetting and photocuring properties, or a resin obtained by mixing a thermosetting resin and a photocuring resin, and is cured through steps of heating and ultraviolet irradiation. Resin can be used as the sealing resin. When a resin that cures through two steps is used, a sealing member with higher sealing performance can be realized.

As a method of forming the seal members 3a, 3b, 3c, a dispenser drawing method can be applied other than the screen printing method. In this dispenser drawing method, the seal member 3a, 3a is placed on the transparent electrode 2b by sending a sealing resin from the tip of the dispenser while moving a delivery device called a dispenser.
This is a method of drawing the shapes b and c.

In either case, the sealing members 3a,
3b is formed in a step of forming the seal member 3c using a material and a method of forming the seal member 3c. Therefore, the seal members 3a and 3b of the present invention do not require any special process other than the process of forming the seal member 3c.

After the seal members 3a, 3b and 3c are cured, a conductive paste is applied to the inside of the seal members 3a and 3b as the conductive members 4a and 4b. In addition, as a material of the conductive members 4a and 4b, a method of using metal spheres such as gold or silver other than the conductive paste is also conceivable.

The glass substrates 1a and 1b are placed on the glass substrate 1a.
As a spacer for keeping the thickness of the liquid crystal layer 7 sandwiched between them, that is, the gap width between the glass substrates 1a and 1b constant, about 100 fine particles having an average particle diameter of 9.0 μm, which are crosslinked copolymers, are used. sprayed at a density of mm ^2. Then, the glass substrates 1a and 1b are bonded together with the transparent electrodes 2a and 2b inside, and are heated at a temperature of 150 ° C. for about 2 hours while being uniformly pressed at a pressure of about 1 kg / cm ² , to about 8.8 μm
Create an empty cell having a cell thickness of

A liquid crystal material is injected into the empty cell thus formed by a vacuum injection method. In addition to the vacuum injection method, a normal pressure injection method, a pressure injection method, or the like may be used.

Next, a sealing resin is applied to the opening 5 while continuously pressing the empty cell into which the liquid crystal is injected from outside using a pressing device. When the applied sealing resin is irradiated with ultraviolet rays, the opening 5 is sealed.

When the periphery of the conductive members 4a and 4b of the liquid crystal display element 10 formed as described above is observed with a microscope, no liquid crystal material is observed. That is, according to the present invention, by forming the seal members 3a and 3b so as to surround the conductive members 4a and 4b, when the liquid crystal material is filled in the empty cells, the liquid crystal material around the conductive members 4a and 4b is filled. Intrusion can be prevented.

Thereafter, the liquid crystal display element 10 is subjected to ultrasonic cleaning with a mixed solution of ethanol and water. After washing
When observed again by the microscope, no change is observed in the conductive members 4a and 4b.

As described in detail above, in the present embodiment, the liquid crystal display element 10 has the liquid crystal layer 7 made of only a liquid crystal material. The present invention can also be applied to a liquid crystal display element called a polymer dispersion type.

This polymer-dispersed liquid crystal display element is such that liquid crystals are dispersed in a water-drop shape in a polymer compound having a three-dimensional network structure, instead of a liquid crystal layer filled only with a liquid crystal material. Or, it is a liquid crystal display device having a liquid crystal layer 7 in which water droplet liquid crystals are connected to each other and dispersed in a network.

In this case, a composite material composed of a liquid crystal material and a substance at a stage before the polymer compound (hereinafter, referred to as a polymer precursor) is injected into the empty cell by a vacuum injection method. After the opening 5 is sealed in the same manner, the composite material in the liquid crystal layer 7 is irradiated with ultraviolet light having an intensity of 50 mW / cm ² for 5 minutes.
By irradiating for one minute, the polymer precursor in the cell is polymerized and at the same time, the liquid crystal material and the polymer compound undergo phase separation, and a liquid crystal layer composed of liquid crystal and the polymer compound appears.

In the present embodiment, the liquid crystal display element 1
0 has been described as a transmissive liquid crystal display element in which both of the pair of opposing substrates are transparent glass substrates provided with transparent electrodes. In addition to the present embodiment, for example, if a reflective electrode that reflects light is used instead of the transparent electrode 2a, a reflective liquid crystal display element having the effects of the present invention can be configured.

In order to form a reflection type liquid crystal display element, in the active element forming section 6, instead of the transparent electrode divided for each pixel connected to the TFT element, a reflection electrode divided for each pixel is used. It is also conceivable to provide such a configuration.

Further, in the present embodiment, the liquid crystal display element 10 is provided with a transparent electrode for each pixel and T
The description has been given as having the FT element. However, the present invention can be similarly applied to a simple matrix type liquid crystal display element having no transparent electrode and switch means for each pixel.

[0044]

As described above, according to the present invention,
By forming a sealing member as a protection member around a conductive member that electrically connects the two transparent electrodes, a liquid crystal material or the like that has entered the outside of the inter-substrate seal is washed and removed.
The conductive member can be protected from contamination and the like.

[Brief description of the drawings]

FIG. 1 shows a liquid crystal display device 10 according to an embodiment of the present invention.
Perspective view showing a state in which the liquid crystal display element 10 is disassembled for explaining the structure of FIG.

FIG. 2 shows a seal member 3a according to an embodiment of the present invention.
The figure which shows the pattern of the screen printing plate for forming 3b, 3c

FIG. 3 is a perspective view showing a state where the liquid crystal display element 40 is disassembled to explain the structure of the conventional liquid crystal display element 40.

[Explanation of symbols]

 1a, 1b Glass substrate 2a, 2b Transparent electrode 3a, 3b, 3c Sealing member 4a, 4b Conducting member 5 Opening 6 Active element forming part 7 Liquid crystal layer 8 Screen printing plate 9a, 9b, 9c Penetration pattern 10 Liquid crystal display element 31a, 31b Glass substrate 32a, 32b Transparent electrode 33 Sealing member 34a, 34b Conducting member 35 Opening 36 Active element forming part 37 Liquid crystal layer 40 Liquid crystal display element

Claims (8)

[Claims] 1. A pair of opposing substrates having voltage applying means, at least one of which is transparent, a liquid crystal layer sandwiched between the pair of opposing substrates, and a liquid crystal layer provided between the pair of opposing substrates. A liquid crystal display device comprising: a sealing member for sealing; a conductive member provided on the pair of opposing substrates for electrically connecting the voltage applying means; and a protection member surrounding the conductive member. 2. A sealing resin, which is a material of the sealing member and the protection member, is a thermosetting resin or a photosetting resin, a thermosetting and photosetting resin, or a thermosetting resin. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is a resin obtained by mixing a resin and a photocurable resin. 3. The liquid crystal according to claim 1, wherein the liquid crystal layer comprises a polymer compound having a three-dimensional network structure and a liquid crystal dispersed in the polymer compound. Display element. 4. The liquid crystal display device according to claim 1, wherein said pair of opposing substrates are transparent substrates having a voltage applying means provided with a transparent electrode. 5. The method according to claim 1, wherein at least one of the pair of opposed substrates is a transparent substrate, and the voltage applying unit is provided with a transparent electrode on the transparent substrate and a reflective electrode on the other substrate. The liquid crystal display device according to claim 1. 6. The liquid crystal display device according to claim 2, wherein the protection member is formed using the sealing resin and a method of forming the sealing member in the step of forming the sealing member. Manufacturing method. 7. The method according to claim 6, wherein the method of forming the seal member is a screen printing method. 8. The method according to claim 6, wherein the method for forming the seal member is a dispenser drawing method.