JP2003255353A - Liquid crystal display element and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element wherein contrast is improved and the occurrence of bubbles and alignment defects is suppressed. <P>SOLUTION: The liquid crystal display element is characterized in that a liquid crystal composition in a liquid crystal state is disposed in a display part between a pair of substrates provided with electrodes and a mixture in a liquid crystal gelling state consisting of the liquid crystal composition and a low molecular gelatinizer for physically gelatinizing the liquid crystal composition is disposed in a non-display part between the substrates. <P>COPYRIGHT: (C)2003,JPO

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 in which a gel-like substance showing liquid crystallinity and having no fluidity is arranged in a portion corresponding to a non-display portion between a pair of substrates and a method for manufacturing the same.

[0002]

2. Description of the Related Art A liquid crystal display device using a gel-like substance having liquid crystallinity is disclosed in JP-A-5-216015 and 8-25468.
No. 8, 11-52341, 11-256164, and JP-A No. 2000-239663.
Liquid crystal devices are widely used as displays for various devices because they are thin, lightweight, and excellent in power saving. Nowadays, especially as personal computer monitors and TVs,
It is becoming more popular as it replaces CRTs. Moreover, as a display element of a portable electronic device, its characteristics are fully utilized. A liquid crystal display device is generally configured by sandwiching a liquid crystal composition between two thin substrates, but some kind of external stimulus may cause bubbles or misalignment in the liquid crystal device. Sometimes. In particular, in the case of a liquid crystal display element that is required to be thin in portable electronic devices, a thin glass substrate (about 0.
4mm thick) and plastic substrate (thickness 100-250μ)
Since m) is used, the occurrence of bubbles and poor orientation is an important quality issue.

The inventors of the present invention have previously provided a liquid crystal display device in which generation of bubbles and the like is suppressed by gelling the liquid crystal by adding a compound capable of gelling the liquid crystal to the liquid crystal. Further, in order to improve the contrast among them, a liquid crystal display device using a plastic substrate, in particular, using a transparent gel in the visible light region to show optical rotatory power and birefringence, is provided. There is. However, when a liquid crystal gel layer obtained by adding a gelling agent to liquid crystal is used as a light control layer, when the gelling agent concentration is high,
Although it is possible to enhance the durability so as not to generate bubbles, there have been problems such as deterioration of contrast and increase of drive voltage.

[0004]

The problems to be solved by the present invention are as follows. (1) To provide a liquid crystal display device that improves contrast and suppresses the occurrence of bubbles and alignment defects. (2) To provide a liquid crystal display device in which the liquid crystal gel state of the non-display portion is stable. (3) To provide a liquid crystal display device having uniform display characteristics. (4) To provide a plastic liquid crystal display device having high display quality, light weight, and excellent flexibility. (5) To provide a method for manufacturing a liquid crystal display device having high contrast and suppressing the occurrence of bubbles and alignment defects. (6) To provide a method for manufacturing a liquid crystal display device, which has high contrast and suppresses the occurrence of bubbles and alignment defects. (7) To provide a method for manufacturing a liquid crystal display device having high productivity and higher contrast. (8) To provide a method for manufacturing a liquid crystal display device with higher productivity. (9) To provide a method for manufacturing a liquid crystal display device having uniform display characteristics.

[0005]

Means for Solving the Problems In the liquid crystal display device in which a light control layer containing a liquid crystal substance is formed between a pair of glass substrates or a plastic substrate of 250 μm or less, the present inventors have found that bubbles, misalignment, etc. As a result of studying to suppress the occurrence of defects, it was found that inclusion of a compound capable of physically gelating a liquid crystal between both substrates can suppress the generation of bubbles. It has been found that this effect can be sufficiently achieved by disposing a gel in which a liquid crystal is physically gelled (hereinafter referred to as a liquid crystal gel) only in the non-display portion. In this case, since the light control layer containing only the conventional liquid crystal composition is formed in the display portion, a liquid crystal display device having high contrast and capable of being driven at a low voltage can be obtained.

By making the sol-gel transition temperature of the liquid crystal gel present in the non-display portion lower than the liquid crystal-isotropic liquid phase transition temperature of the liquid crystal, when the liquid crystal gel portion is damaged by external stimulus or the like, It has been found that the liquid crystal gel portion, which is once turned into a sol state by heating and then rapidly cooled, does not spread to the display portion and can be restored. The amount of gelling agent is
It is desirable that the liquid crystal gel has a range transparent to visible light. When the amount of the gelling agent is large, the liquid crystal gel is in a light-scattering state, so that it is not possible to secure the uniformity of the display portion and the non-display portion, and the display quality is deteriorated. By using an appropriate amount of gelling agent, a liquid crystal display device having uniform display characteristics can be obtained.

In order to obtain a liquid crystal display device having high display quality, light weight and excellent flexibility, it is advantageous to form the plastic substrate used for the liquid crystal display device with a polycarbonate or a polyether sulfone of 250 μm or less. I found that. In order to form the liquid crystal gel layer in the non-display area in the manufacturing method with high contrast and high productivity of the liquid crystal display element in which the occurrence of bubbles and alignment defects is suppressed, the gelling agent is previously formed in the part of one substrate. It was found that it is effective to print cells by a simple method such as flexo printing or screen printing, and to bond them to another substrate via a gap material to make a cell, and to heat-cool after injecting liquid crystal between the substrates. It was In addition, after printing a mixture of liquid crystal and gelling agent in a liquid crystal gel state, leaving a liquid crystal injection opening on a part of the non-display portion of one substrate, the other material is intercalated with a gap material. By injecting liquid crystal into the bonded cells, a liquid crystal display device having high contrast and suppressing generation of bubbles and alignment failure could be obtained.

Further, by printing a mixture of the above-mentioned gelling agent or liquid crystal gel mixture with the gap material in advance, the step of spraying the gap material becomes unnecessary, and a highly productive manufacturing method can be realized. . In this case, since the gap material is not present in the display portion, light leakage in black display in the gap material portion can be prevented, so that a display element with higher contrast can be realized. A gap material provided with a gelling agent is placed in a non-display part by printing or the like to form a cell, and a liquid crystal gel layer can be injected by heating-cooling after liquid crystal injection, and a liquid crystal display element can be efficiently produced. . As a result of various studies to provide a method for producing a liquid crystal display device having uniform display characteristics, the gelling agent is not at room temperature in the step of injecting liquid crystal after the gelling agent or the liquid crystal gel mixture is present between both substrates. It has been found that a substance that is immiscible with the liquid crystal can prevent the bleeding of the gelling agent into the liquid crystal layer of the display section.

According to the present invention, there are provided the following liquid crystal display element and a method for manufacturing the liquid crystal display element. (1) A liquid crystal composition in a liquid crystal state is disposed in a display portion between a pair of substrates provided with electrodes, and a liquid crystal composition and a low-molecular gel that physically gelates the liquid crystal composition in a non-display portion between the substrates. A liquid crystal display device, in which a liquid crystal gel state mixture comprising an agent is disposed. (2) The sol-gel transition temperature of the liquid crystal gel state mixture is
The liquid crystal display device according to (1) above, which is lower than the liquid crystal-isotropic liquid phase transition temperature. (3) The liquid crystal display device as described in (1) or (2) above, wherein the amount of the low molecular weight gelling agent is in a range that provides a liquid crystal gel state mixture that is transparent to visible light. . (4) The substrate (1) to (3), wherein the substrate is made of polycarbonate or polyether sulfone.
5. The liquid crystal display device according to any one of 1. (5) In order to obtain the liquid crystal display element according to any one of (1) to (4), a portion having a gap material between a pair of substrates and corresponding to a non-display portion on any one of the substrates. A method for manufacturing a liquid crystal display device, characterized in that a liquid crystal is sealed between substrates on which a low molecular weight gelling agent is previously arranged. (6) In order to obtain the liquid crystal display element according to any one of (1) to (4), a portion having a gap material between a pair of substrates and corresponding to a non-display portion on one of the substrates. A method for manufacturing a liquid crystal display device, characterized in that a liquid crystal is sealed between the substrates on which the liquid crystal gel state mixture is previously arranged. (7) A predetermined amount of a gap material is mixed with the low molecular weight gelling agent or the liquid crystal gel state mixture, and the mixture is preliminarily arranged at a portion corresponding to a non-display portion on one of the substrates. The method for manufacturing a liquid crystal display element according to (5) or (6) above. (8) One of the above (5) or (6), characterized in that the gap material provided with the low molecular weight gelling agent is previously arranged at a portion corresponding to the non-display portion on one of the substrates. A method for manufacturing the liquid crystal display element according to 1. (9) In any one of the above (5) to (8), wherein the low molecular weight gelling agent or the liquid crystal gel state mixture arranged in the non-display portion is immiscible with the liquid crystal when the liquid crystal is sealed in the display portion. A method for producing the liquid crystal display element described.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In a liquid crystal display device of the present invention, a liquid crystal composition in a liquid crystal state is disposed in a display portion between a pair of substrates provided with electrodes, and a non-display portion between the substrates is provided. And a liquid crystal gel state mixture comprising the liquid crystal composition and a low molecular weight gelling agent which physically gelates the liquid crystal composition. The liquid crystal display device having such a structure according to the present invention is of high quality in which the occurrence of bubbles with improved contrast and the occurrence of alignment defects are suppressed.

The inventors of the present invention have conducted an air bubble generation experiment in a liquid crystal display device having a basic structure, and have found that one of the factors causing the air bubble generation is air bubble generation due to pressing. This means pressing and deforming the surface of the display element in some form. When the substrate is deformed by pushing and the pushing force is released when the space between the deformed parts is thin, the flow of liquid crystal occurs as the substrate suddenly returns to its original state, and this part is surrounded by the surrounding area. It was presumed that a negative pressure was generated in comparison with the above, and bubbles were generated. This is remarkable when a flexible substrate, particularly a film substrate having a thickness of 250 μm or less is used. Furthermore, when the substrates are pressed with such a large force that they come into contact with each other, the alignment treated surfaces may rub against each other and the alignment state of the liquid crystal may be disturbed, resulting in discoloration of the display surface. .

In order to solve the above problems, the inventors of the present invention arranged a solid-like liquid crystal gel layer having a small fluidity between the substrates in the non-display area. As a result, the display element is less likely to cause alignment failure due to increased durability against pressure, and since the liquid crystal layer of the display section is surrounded by the non-flowable liquid crystal gel wall of the non-display section, The sudden flow of the liquid crystal is alleviated and the negative pressure is suppressed so that the generation of bubbles is prevented.

The liquid crystal gel state mixture as used herein means a mixture of a liquid crystal composition and a low molecular weight gelling agent in a state where the liquid crystal composition is physically gelled by the low molecular weight gelling agent. In this case, the liquid crystal composition is incorporated into the three-dimensional network structure formed by the low molecular weight gelling agent and is in a non-fluid gel state. This liquid crystalline gel state mixture has a three-dimensional network structure formed by the low molecular weight gelling agent in a physical gelation state caused by intermolecular hydrogen bonding of the gelling agent, so that the non-fluidic gel is formed by heating. The state changes reversibly (transition) to a fluid sol state (liquid state).

The low-molecular gelling agent used in the present invention has a property of forming a three-dimensional network structure by intermolecular hydrogen bonding and incorporating a fluid substance (liquid substance) into the network structure to cause gelation. And shows an action of gelling the liquid crystal composition when mixed with the liquid crystal composition. The low molecular weight gelling agent having the above-mentioned properties used in the present invention is a known substance.

In the low molecular weight gelling agent used in the present invention, the low molecular weight means that the gelling agent is a compound having no molecular weight distribution. Its molecular weight is 2000
In the following, it is particularly preferably 1000 to 2000.
The molecular structural conditions that allow intermolecular hydrogen bonding are generally amide group (-NHCO-) and amino group (-NH-).
And a carbonyl group (—CO—) in combination are desirable. In addition to this, carbamate group, urea group,
There may be a carboxyl group, an alkoxy group, a phosphoric acid group, a hydroxyl group, and the like, and the number and position of these are not particularly limited. In the present invention, among such gelling agents, it is particularly preferable to use a compound having two or more groups capable of intermolecular hydrogen bonding and two or more alkylene groups in each molecule. It is preferable that the alkylene group has a long chain structure having 4 or more carbon atoms, preferably 6 to 20 (may have a branch), since the solubility in the liquid crystal is high. The gelling agent preferably has a chiral structure. In particular,
JP-A-5-216015, 8-254688, 11
-21556, 11-52341, JP-A-200
A low molecular weight gelling agent disclosed in, for example, 0-239663 can be used. The liquid crystal gel referred to in the present invention is a physical gel and refers to one capable of reversibly changing from a gel state to a sol state. The structure of the cross-linking part of the three-dimensional network structure is not limited as long as it is possible to change from the gel state to the sol state, but the cross-linking structure is generally due to a secondary bonding force other than covalent bond. There are many. The secondary binding force mentioned here is based on intermolecular force bonding (hydrogen bond, molecular orientation, helix formation, lamella formation, etc.) and ionic bond. The transformation of the gel into a sol by intermolecular force bonding can generally be caused by raising the temperature.

The liquid crystal used in the present invention includes
Liquid crystal molecules conventionally used for liquid crystal display devices, specifically, various liquid crystal molecules such as biphenyl-based or phenylcyclohexane-based liquid crystal molecules exhibiting a nematic or smectic phase can be used.

In the liquid crystal display device of the present invention, it is important that the sol-gel transition temperature of the liquid crystal gel in the non-display area is lower than the liquid crystal-isotropic liquid phase transition temperature of the liquid crystal. As described above, the liquid crystal gel loses fluidity when the liquid crystal is incorporated in the three-dimensional network structure of the low molecular weight gelling agent molecules. This three-dimensional network structure does not break unless heated above the sol-gel transition temperature, so it exists stably at temperatures below that. When the liquid crystal gel part is damaged due to external stimulus, etc., once it is brought into a sol state by heating to a temperature slightly higher than the sol-gel transition temperature, preferably within + 5 ° C.,
By rapidly cooling, it is possible to prevent the regelled liquid crystal gel portion from spreading to the display portion and restore the gel state. Higher than sol-gel transition temperature (5
When the temperature is higher than the liquid crystal-isotropic liquid phase transition temperature of the liquid crystal for a long time, the gelling agent diffuses in the liquid crystal, and when cooled to room temperature, the liquid crystal gel layer reaches the display unit. Spread, and display characteristics vary. The preferred sol-gel transition temperature of the liquid crystal gel state mixture according to the present invention is 10 ° C or higher than the liquid crystal-isotropic liquid phase transition temperature,
The temperature is preferably 20 ° C. or lower.

The amount of the gelling agent used in the present invention is preferably such that the light control layer is transparent to visible light. The amount of the gelling agent required to gel the liquid crystal is 0.05 to 10 wt% with respect to the liquid crystal. The optimum amount of the gelling agent varies depending on the types of the liquid crystal and the gelling agent, but is preferably in the range where the liquid crystal does not scatter visible light, that is, in the transparent range. In other words, it is preferable to select a compound capable of gelling in the transparent range. The specific amount of the liquid crystal that can be gelled in the transparent range is 0.4 wt% or less, and more preferably 0.2 wt% or less.

As the display element substrate of the present invention, a plastic substrate or a glass substrate can be used, but the use of a plastic substrate is preferable. The plastic substrate is preferably transparent to visible light due to the nature of the display device, and general-purpose polymer materials such as polyolefin-based, polyester-based, polyacrylate-based, and polyether-based can be used, but the retardation is small. Materials having low gas permeability (moisture, oxygen, nitrogen), high visible light permeability, low linear expansion coefficient, and high heat resistance are preferable. In particular, it is preferable to use one having a thickness of 250 μm or less because of its lightness, thickness, and non-breakage. However, as the thickness of the substrate becomes thinner, the substrate is more likely to be deformed due to external pressure, so that the risk of bubble generation increases. Becomes The embodiment of the present invention exerts a particularly great effect when such a thin plastic film is used. It is conventionally known to use a plastic substrate as a substrate, and it has been disclosed that a plastic substrate can be used in a group of patents that use the technique of gelating a liquid crystal with a low molecular weight gelling agent described above. However, it does not have the idea of solving the object like the present invention, and merely discloses that it can be used as a substrate for holding a gelled liquid crystal. The plastic substrate used in the present invention has a thickness of 80 to 250 μm, preferably 100 to 200 μm.
Is.

Polycarbonate and polyether sulfone are most suitable as the plastic substrate preferably used in the present invention. A substrate of about 250 μm made of such a material has retardation, visible light transmission, and heat resistance (~
150 ° C.), the substrate is excellent in lightness and thickness, and when a display element is formed, it is possible to provide a liquid crystal display element having high display quality and excellent in lightness, flexibility and productivity.

Next, a manufacturing method for forming a liquid crystal display element having a liquid crystal gel layer between the non-display area substrates with high productivity will be described in detail. FIG. 1 shows the basic steps of one of the preferable methods for manufacturing the liquid crystal display device according to the present invention. Two first and second substrates on which a predetermined electrode pattern was formed and subjected to orientation treatment were prepared, and one of the substrates (the first substrate in FIG. 1) was dissolved with a gelling agent of a predetermined concentration. The coating solution was applied to the non-display area by flexographic printing or the like. The substrate after coating is heated and dried to remove the solvent. In consideration of seepage to the display area, it is desirable to apply the solution in a range narrower than the width of the non-display area. A gap material is sprinkled on the second substrate, and the two substrates are bonded together via a sealant (adhesive) to form an empty cell. After injecting liquid crystal into this empty cell,
The mixture is heated to a temperature at which the applied gelling agent and the liquid crystal are mixed (a temperature slightly higher than the sol-gel transition temperature measured in advance), and when they are mixed, the mixture is immediately cooled to room temperature. In this way, it is possible to realize a highly productive manufacturing method of a liquid crystal display device having a liquid crystal gel layer between the substrates of the non-display portion, having high contrast and free from bubbles, alignment defects and the like.

FIG. 2 shows the basic steps of another preferable method for manufacturing the liquid crystal display device according to the present invention. Similar to FIG. 1, one of the two substrates was mixed with a liquid crystal and a gelling agent in advance, and a mixture in a liquid crystal gel state was applied by screen printing or the like, and a gap material was applied to the other substrate. After spraying, the two substrates were attached to each other via a sealant to prepare an empty cell. The amount of the mixture in the liquid crystal gel state applied is such that the liquid crystal gel wall is to be formed in the non-display portion between the bonded substrates. Further, the coating pattern needs to have an opening for liquid crystal injection (see FIG. 2). Thus, similar to the above-mentioned manufacturing method, a liquid crystal display device having a liquid crystal gel layer between the non-display substrate, high contrast, high productivity of a liquid crystal display element free from bubbles, misalignment, etc. Can be realized.

The above-mentioned manufacturing method is a manufacturing method in which the gelling agent or the mixture in the liquid crystal gel state is applied to the first substrate and the gap material is sprinkled on the second substrate. A simpler manufacturing method can be provided by mixing the gap material with the coating material and applying the gap material.

When manufacturing a liquid crystal display device according to the present invention, the gap material to which the gelling agent is applied is dispersed in a solvent, and this dispersion liquid is applied by printing to form the gap material and the gelling agent in a predetermined pattern. A manufacturing method of simultaneously arranging can be provided. Also in this case, the steps of removing the solvent by heating and drying after coating and forming the liquid crystal gel layer by heating and cooling after injecting the liquid crystal are required, but this is a highly productive manufacturing method. However, in the above manufacturing method, since the gap material is arranged only in the non-display part, when the area of the display part is larger than that of the non-display part, the cell thickness uniformity of the display part cannot be maintained. Therefore, it is necessary to pay attention to the display pattern of the element to be manufactured. The gap material to which the gelling agent is applied means that the gelling agent is adhered to or coated on the surface of the gap material composed of spherical polymer resin beads, inorganic silica particles and the like.

When a liquid crystal display device having uniform display characteristics is manufactured according to the present invention, the gelling agent is used at room temperature in the step of injecting the liquid crystal after the gelling agent or the liquid crystal gel mixture is present between both substrates. By being a substance immiscible with, it is possible to prevent the gelling agent from oozing into the liquid crystal layer of the display section.

As described above, in the manufacture of the display element of the present invention, it is important that the gelling agent or the liquid crystal gel mixture printed at the time of injecting the liquid crystal into the empty cell does not mix the liquid crystal. If mixed, gelation will occur according to the injection of liquid crystal, and further injection will not be possible, or a phenomenon will occur in which the gelling agent diffuses to the display part in the cell to form liquid crystal gel. The uniform display performance of can not be secured. This phenomenon can be avoided by selecting a compound that is immiscible with the liquid crystal at the temperature at which the liquid crystal is injected. The fact that the compound that gels the liquid crystal does not mix with the liquid crystal means that the solubility of the gelling agent in the liquid crystal is sufficiently low or a sufficiently long dissolution time is required in the operating environment temperature range used as a display element. It doesn't have to be immiscible at all. After injecting the liquid crystal, the temperature is once heated to a temperature higher than the sol-gel transition point in order to promote mixing, and then,
The liquid crystal display device of the present invention can be provided by cooling to room temperature.

[0027]

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Example 1 A substrate having dimensions of 30 mm × 40 mm (0.4 mm)
Two glass substrates (thickness) were prepared, an ITO electrode layer was formed so as to obtain a display as shown in FIG. 3, polyimide was laminated as an alignment treatment film, and the surface thereof was rubbed. On one of the two substrates, a low-molecular gelling agent (ZI18) dissolved in a solvent was screen-printed on the gelling agent coating pattern shown in FIG. 3 and dried by heating. Next, an amine-cured epoxy resin as a sealant was dispenser coated on the outside of the portion coated with the gelling agent. On the other substrate, silica beads (gap material) having a particle size of 5 μm were used with isopropyl alcohol as a solvent, and the number was about 100 / mm ^2.
Sprayed at a density of.

The two substrates were bonded, fixed and cured so that the rubbing directions were orthogonal to each other to form a TN device, and an empty cell was produced. Next, the empty cell was moved to a vacuum device for liquid crystal injection, the pressure was reduced to 0.002 Torr, the liquid crystal injection port of the cell was attached to the liquid crystal dish, and the outside of the cell was returned to normal pressure.
After introducing the liquid crystal into the cell and injecting it, the injection port was closed with a sealant and cured to obtain a liquid crystal cell. The injected liquid crystal was TN with a nematic-isotropic liquid phase transition temperature of 106 ° C.
Liquid crystal was used. The application amount of the gelling agent was adjusted so that the concentration of the gelling agent in the liquid crystal gel layer formed in advance in the gelling agent application portion was about 0.4 wt%. Since the sol-gel transition temperature at this gelling agent concentration is about 67 ° C., the liquid crystal cell was heated to about 70 ° C., the gelling agent and the liquid crystal were mixed, and the mixture was quickly cooled to room temperature. When this cell was observed with a microscope, it was confirmed that a three-dimensional network structure of the gel was formed in the gelling agent-coated portion, and that a transparent liquid crystal gel layer was formed. Polarizing plates were arranged above and below the cell prepared by the above procedure to obtain a TN liquid crystal display element. The display characteristics of the device thus obtained were exactly the same as the display properties (contrast 25: 1) of the TN liquid crystal display device having the liquid crystal gel layer in the non-display portion, which was manufactured using the same material and cell parameters. .

A test (pressing test) of pressing the surface of the prepared liquid crystal cell with stainless steel having a tip shape with a curvature (r) of 4 mm was carried out in the cell before installing the polarizing plate. The pressure test was conducted at 16 locations (4 vertical × 4 horizontal) inside the sealant at regular intervals. After the test, defects such as air bubbles and poor orientation did not occur.

The gelling agent (Z118) has the following structural formula (1).

[Chemical 1]

Example 2 Similar to Example 1, the substrate had a size of 30 mm × 40.
Prepare 2 mm (0.4 mm thick) glass substrates and
Form the ITO electrode layer so that the display as shown in
Polyimide was laminated as an alignment treatment film, and the surface was rubbed. The same TN liquid crystal as in Example 1 was mixed with 0.4 wt% of a low molecular weight gelling agent (ZI18) and mixed by heating, and then cooled to obtain a liquid crystal gel state mixture. One of the substrates was screen-printed with the liquid crystal gel layer coating pattern shown in FIG. Next, an amine-cured epoxy resin as a sealant was dispenser coated on the outside of the portion coated with the liquid crystal gel layer. Silica beads with a particle size of 5 μm (gap material) on the other substrate
With isopropyl alcohol as a solvent, about 100 /
Sprayed at a density of mm ² . The two substrates were bonded and fixed and cured so that the rubbing directions were orthogonal to each other to form a TN device, and an empty cell was produced. Next, the empty cell was moved to a vacuum device for liquid crystal injection, the pressure was reduced to 0.002 Torr, the liquid crystal injection port of the cell was attached to the liquid crystal dish, the outside of the cell was returned to normal pressure, and the liquid crystal was introduced into the cell. The liquid crystal cell could be obtained by closing the injection port with a sealant and curing. When this cell was observed with a microscope, it was confirmed that a three-dimensional network structure of gel was formed in the liquid crystal gel layer-coated portion and that a transparent liquid crystal gel layer was formed. Polarizing plates were arranged above and below the cell prepared by the above procedure to obtain a TN liquid crystal display element. The display characteristics of this element were exactly the same as the display characteristics of the TN liquid crystal display element, which was made of the same material and cell parameters and had no liquid crystal gel layer in the non-display part. In addition, a test (pressing test) of pressing the surface of the produced liquid crystal cell with stainless steel having a tip shape with a curvature (r) of 4 mm was performed in the cell before the polarizing plate was installed. The pressure test was conducted at 16 locations (4 vertical × 4 horizontal) inside the sealant at regular intervals. After the test, defects such as air bubbles and poor orientation did not occur.

Example 3 In Example 1, a low-molecular gelling agent (ZI18) dissolved in a solvent was mixed with silica beads (gap material) having a particle diameter of 5 μm on one substrate. The gelling agent coating pattern shown was screen-printed and dried by heating.
The other substrate was dispenser coated with an amine-cured epoxy resin as a sealant. These two substrates,
Then, the rubbing directions were orthogonal to each other, and the TN elements were bonded to each other and fixed and cured to prepare an empty cell. Liquid crystal was injected into this empty cell in the same manner as in Example 1, and a liquid crystal gel layer formation treatment was performed to manufacture a liquid crystal cell. Since there is no gap material in the surface of the display and there is little light leakage in the black display state, 2
A liquid crystal display device having a high contrast of 8: 1 or more was obtained. The same pressing test did not cause any problems. In addition, the process was highly productive with no gap material spraying process.

Example 4 The liquid crystal gel mixture of Example 2 mixed with silica beads (gap material) having a particle size of 5 μm was screen-printed on one substrate in a liquid crystal gel layer coating pattern shown in FIG. ,
A liquid crystal gel layer containing a gap material was formed. A sealant was applied to the other substrate, and these two substrates were bonded to each other to form a TN device, thus producing an empty cell. When the same liquid crystal was injected into this empty cell and its display characteristics were measured, the same high contrast as that of the device of Example 3 was obtained.

Example 5 Silica beads having a particle diameter of 5 μm (gap material) and a gelling agent (ZI18) were mixed in a methylene chloride solvent, and the solvent was volatilized to obtain a gap material having the gelling agent applied to the surface thereof. It was A coating solution prepared by mixing the gap material with isopropyl alcohol is printed on one substrate as in Example 1, and a sealing agent is coated on the other substrate, and these two substrates are used as a TN device. Thus, a bonded empty cell was produced. Liquid crystal was injected into this empty cell in the same manner as in Example 1, and a liquid crystal gel layer formation treatment was performed to manufacture a liquid crystal cell. The display characteristics were the same as in Example 3.

Example 6 Liquid crystal display elements similar to those in Examples 1 to 5 were produced using a polyether sulfone (PES substrate: Sumitomo Bakelite, thickness: 150 μm) substrate with ITO. The display characteristics were similar to those of the device having no liquid crystal gel layer in the non-display area, but the generation of bubbles was significantly suppressed.

[0037]

According to the present invention, there are provided a liquid crystal display device having improved contrast and suppressing the generation of bubbles and misalignment, and a method for producing the liquid crystal display device with high productivity.

[Brief description of drawings]

FIG. 1 shows a basic process diagram for one embodiment of a method for producing a liquid crystal display device of the present invention.

FIG. 2 is a basic process chart showing another embodiment of the method for producing a liquid crystal display element of the present invention.

FIG. 3 shows an example of a gelling agent coating pattern formed on a substrate.

FIG. 4 shows another example of a gelling agent coating pattern formed on a substrate.

Continued front page    (72) Inventor Mayuka Nagata             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F term (reference) 2H089 HA10 HA40 JA10 KA11 KA17                       LA07 LA14 QA03 QA04 QA05                       QA11 QA12 QA13 QA14 QA15                       TA01 TA05 TA06

Claims (9)

[Claims] 1. A liquid crystal composition in a liquid crystal state is disposed in a display portion between a pair of substrates provided with electrodes, and a liquid crystal composition and a low-gel which physically gelates the liquid crystal composition in a non-display portion between the substrates. A liquid crystal display device, wherein a liquid crystal gel state mixture comprising a molecular gelling agent is arranged. 2. The liquid crystal display device according to claim 1, wherein the sol-gel transition temperature of the liquid crystal gel state mixture is lower than the liquid crystal-isotropic liquid phase transition temperature. 3. The liquid crystal display device according to claim 1, wherein the amount of the low molecular weight gelling agent is in a range that provides a liquid crystal gel state mixture that is transparent to visible light. 4. The substrate according to claim 1, wherein the substrate is made of polycarbonate or polyether sulfone.
3. The liquid crystal display element according to any one of 3 above. 5. In order to obtain the liquid crystal display element according to claim 1, a gap material is provided between a pair of substrates, and a portion corresponding to a non-display portion on one of the substrates is provided. A method for manufacturing a liquid crystal display device, which comprises enclosing a liquid crystal between substrates on which a low molecular weight gelling agent is arranged in advance. 6. A liquid crystal display device according to any one of claims 1 to 4, wherein a gap material is provided between a pair of substrates and a portion corresponding to a non-display portion on one of the substrates is provided. A method for manufacturing a liquid crystal display device, characterized in that liquid crystal is sealed between substrates on which a liquid crystal gel state mixture is arranged in advance. 7. A predetermined amount of a gap material is mixed with the low molecular weight gelling agent or the liquid crystal gel state mixture, and the mixture is pre-disposed on a portion corresponding to a non-display portion on one of the substrates. 7. The method for manufacturing a liquid crystal display element according to claim 5, which is characterized in that. 8. The liquid crystal according to claim 5, wherein the gap material provided with the low molecular weight gelling agent is previously arranged at a portion corresponding to the non-display portion on either one of the substrates. Display element manufacturing method. 9. The low molecular weight gelling agent or the liquid crystal gel state mixture disposed in the non-display portion is immiscible with the liquid crystal when the liquid crystal is sealed in the display portion. Manufacturing method of the liquid crystal display element of.