JP2000267083A - Liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal display device which can be reduced in thickness and weight by forming a polarizing layer on one side of a substrate by applying a dye having a concentration transition type liquid crystal phase. SOLUTION: Transparent electrodes 4, 4a, insulating layers 6, 6a and alignment layers 8, 8a are formed on the inner faces of upper and lower substrates 2, 2a, respectively, and a liquid crystal material 10 is injected between the substrates and sealed. Polarizing layers 12, 12a are formed on the front and back faces of the device. The polarizing layers 12, 12a are formed by directly applying a dye having a concentration transition type liquid crystal phase on each one surface of the upper and lower substrates 2, 2a so that the layers 12, 12a have the directional property. The thickness of the polarizing layers 12, 12a is controlled to 0.1 to 50 μm, and preferably within the range of 5±3 μm. Since the polarizing layers 12, 12a are formed by direct coating, the thickness and weight of the device itself can be decreased, and the obtd. device can be extremely light in weight and small in size.

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 polarizing layer is formed directly on a substrate of a liquid crystal display device by coating to reduce the thickness and weight of the device itself, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A liquid crystal display device utilizes dielectric anisotropy in which the molecular arrangement of liquid crystal is changed by an externally applied voltage to selectively transmit light emitted from a backlight or externally. Conversely, characters, numbers, and images are displayed by preventing transmission.

[0003] Such a liquid crystal display element employs a polarizing plate in order to control the incident light and actually obtain a display effect. The polarizing plate is prepared by adsorbing a dye as a polarizing element on a polyvinyl alcohol (PVA) film of a water-soluble polymer, and then stretching it 3 to 5 times in a certain direction. It is a laminate of an acetate cellulose-based protective film and is attached to a liquid crystal display element using an adhesive. At this time, the polarizing plate is attached to the front and rear surfaces of the device in the case of the transmission type, and to the front surface of the device in the case of the reflection type.

However, such a conventional polarizing plate has a thickness of 0.2 to 0.3 mm due to its laminated structure, and as a result, there is a problem that the overall thickness of the liquid crystal display element is increased. .

[0005] In particular, in the case of a liquid crystal display (PLCD) using a flexible plastic film as a substrate for ultra-light weight and ultra-slimness, the weight and weight are reduced by the thickness of the polarizing plate as described above. There is a problem that slimming becomes more difficult, the flexibility is reduced, and the curvature of the curved surface display is relatively increased. For the same reason, applying a conventional liquid crystal display element to a smart card, an IC card, and the like has been a major obstacle.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, an object of the present invention is to reduce the thickness and weight of a liquid crystal display device by directly forming a polarizing layer on a substrate of the device by coating. It is an object of the present invention to provide a liquid crystal display element capable of producing the same and a method for producing the same.

[0007]

The liquid crystal display device of the present invention is obtained by adhering substrates having electrodes and alignment layers laminated to each other so as to oppose each other, injecting a liquid crystal substance therebetween, and then sealing. A liquid crystal display device, comprising: a polarizing layer formed on one side of the substrate by coating a dye having a concentration transition type liquid crystal (lyotropic liquid crystal) phase in one side direction.

[0008] The concentration transition type liquid crystal is a chemical system composed of two or more components, particularly an amphiphilic substance such as sodium laurate.
It is a mixture of a compound and a polar solvent such as water.

Here, the amphipathic compound is a substance having two groups having greatly different solubilities in the same molecule. One group is a hydrophilic group having a high solubility in water or another polar substance, and another group is a hydrophobic group having a high solubility in a hydrocarbon compound or a non-polar substance. Examples of the hydrophilic group include, for example, -OH, -COO
_{H, -COONa, -SO 3 K,} -O (CH 2 -CH 2 -
O) _n H, -N (CH ₃ ) ₃ Br, and the hydrophobic groups include -CnH _{2n + 1} , -C ₆ H ₄ -C _n H _{2n + 1} and other long radicals And hydrocarbon chains.

The method of manufacturing a liquid crystal display element according to the present invention comprises a step of coating a dye having a concentration transition type liquid crystal phase on one side of a substrate in one direction and then drying to form a polarizing layer; A step of laminating an electrode and an alignment layer on the upper surface of the substrate or on the other surface of the substrate, and bonding a pair of substrates to each other so that the electrode patterns intersect, and injecting a liquid crystal material therebetween, The method includes a step of sealing.

In the present invention, when the polarizing layer is formed on the other surface of the substrate facing the electrodes and the alignment layer, that is, when it is formed on the front and rear surfaces of the device, it is formed in the final step of the manufacturing process of the liquid crystal display device. it can. At this time, glass or an optically isotropic plastic film can be used as the substrate.

In the opposite case, after the polarizing layer is first formed inside the substrate, the electrodes and the alignment layer can be laminated. In this case, the substrate can be all glass or an optically isotropic and optically anisotropic plastic film.

[0013] The polarizing layer of the present invention is formed with a thickness in the range of 0.1 to 50 µm. Further, a protective layer can be further formed on the upper surface of the polarizing layer. The protective layer has a thickness of 1000 A to 20 μm.
It is formed with the thickness of.

As described above, the liquid crystal display device of the present invention can be made ultra-lightweight and slim, and the entire thickness is reduced, so that the flexibility is improved and the curved surface display can be more easily performed. It can be applied to ultra-thin structures such as smart cards and IC cards.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments for realizing the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a sectional structure of a liquid crystal display device of the present invention.

As shown in FIG. 1, the liquid crystal display device of the present invention comprises transparent electrodes 4 on inner surfaces of upper and lower substrates 2 and 2a, respectively.
4a, insulating layers 6 and 6a and alignment layers 8 and 8a were formed in layers, and a liquid crystal material 10 was injected into a space therebetween and sealed. Then, a polarizing layer 12, a front surface and a rear surface of the device,
12a.

Here, the polarizing layers 12 and 12a of the present invention are:
Instead of the conventional polarizing plate having a laminated structure, it is obtained by directly coating a dye having a concentration transition type liquid crystal phase on one side surface of the upper and lower substrates 2 and 2a so as to have a directivity.

When the dye is dissolved in a solvent, it is arranged in a specific direction like a liquid crystal to form a concentration transition type liquid crystal phase. This is coated on one side of the substrates 2 and 2a in one direction so that the dye molecules are arranged in one side. The solvent is removed by drying to form the polarizing layers 12 and 12a.

At this time, the coating thickness of the polarizing layers 12 and 12a is formed in the range of 0.1 to 50 μm, preferably in the range of 5 ± 3 μm. This thickness is 5
If the thickness exceeds 0 μm, the overall thickness of the liquid crystal display element becomes too large to obtain the expected effects of the present invention.
If it is smaller than 1 μm, it is difficult to obtain the effect as a polarizing layer.

The above-mentioned concentration transition type liquid crystal is a chemical system composed of two or more components, particularly an amphiphilic substance such as sodium laurate.
It is a mixture of a compound and a polar solvent such as water.

Here, the amphiphilic compound is a substance having two groups whose solubility is greatly different in the same molecule. One group is a hydrophilic group having a high solubility in water or another polar substance, and another group is a hydrophobic group having a high solubility in a hydrocarbon compound or a non-polar substance. Examples of the hydrophilic group include, for example, -OH, -COO
_{H, -COONa, -SO 3 K,} -O (CH 2 -CH 2 -
O) _n H, -N (CH ₃ ) ₃ Br, and the hydrophobic groups include -CnH _{2n + 1} , -C ₆ H ₄ -C _n H _{2n + 1} and other long radicals including radicals. And hydrocarbon chains.

As shown in FIG. 1, the polarizing layers 12, 12a of the present invention
To electrodes 4, 4a, insulating layers 6, 6a and alignment layers 8, 8a.
When it is formed on the other surface of the substrates 2 and 2a opposite to the above, that is, when it is formed on the front surface and the rear surface of the liquid crystal display element, it is formed as a final step after the manufacture of the liquid crystal cell. The polarizing layers 12 and 12a are composed of electrodes 4, 4a and insulating layers 6, 6.
a and the alignment layers 8 and 8a can be formed on the substrates 2 and 2a.

In this case, the substrates 2, 2a are provided with the polarizing layer 1
It is desirable to use glass or an optically isotropic plastic film in consideration of the optical characteristics of 2, 2a.
This is to prevent the light that is linearly polarized through the polarizing layers 12 and 12a from being refracted by the substrates 2 and 2a before reaching the liquid crystal material 10 and changing the optical characteristics.

On the other hand, the liquid crystal display device according to the present invention has the structure shown in FIG.
As shown in the figure, the polarizing layers 12, 12 are provided inside the substrates 2, 2a.
First, a can be formed, and electrodes 4, 4a, insulating layers 6, 6a, and alignment layers 8, 8a can be formed on the inner surfaces thereof.

In this case, the polarizing layers 12 and 12a must be made of a material that can withstand the sintering temperature of the alignment layers 8 and 8a of 200 ° C. or more in the manufacturing process of the liquid crystal display element. This is possible by using the dye having the concentration transition type liquid crystal phase of the present invention.

In such a case, the substrates 2 and 2a can be made of glass or an optically isotropic plastic film. The light linearly polarized by the polarizing layers 12 and 12a immediately enters the liquid crystal material 10 and
An optically anisotropic plastic film, which is relatively inexpensive because it is not affected by a, can be used.

In the present invention, it is preferable to use a plastic film as the substrates 2, 2a. Since the plastic film has flexibility, it is advantageous to adapt to a smart card or an IC card, and a roll-to-roll method can be applied, so that the manufacturing process can be easily realized.

The substrates 2, 2 on which the electrodes 4, 4a, the insulating layers 6, 6a and the alignment layers 8, 8a are laminated on the upper surfaces together with the polarizing layers 12, 12a, are adhered to each other so that the electrode patterns intersect. In the meantime, the liquid crystal material 10
After injecting, the liquid crystal display device of the present invention can be manufactured by sealing.

On the other hand, the polarizing layers 12 and 12a of the present invention have heat resistance and durability themselves. However, if necessary, a protective layer can be further formed on the upper surface thereof. Since the protective layer at this time is hard coated,
It is formed with a thickness of 1000 A to 20 μm.

When the liquid crystal display device of the present invention is of a reflection type, the polarizing layer 12 can be formed only on the upper or front substrate 2.

[0032]

As described above, according to the present invention,
Since the polarizing layer is formed by directly coating the substrate, the thickness and weight of the device itself can be reduced, and the device can be made ultra-light and slim.

In the case of a plastic liquid crystal display device, the flexibility can be improved by reducing the thickness of the device, and as a result, a curved surface display can be realized more easily.

Further, the liquid crystal display device according to the present invention can be applied to ultra-thin structures such as smart cards and IC cards.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a liquid crystal display device of the present invention.

FIG. 2 is a sectional view showing another example of the liquid crystal display device of the present invention.

[Explanation of symbols]

 2, 2a substrate 4, 4a electrode 6, 6a insulating layer 8, 8a alignment layer 10 liquid crystal material 12, 12a polarizing layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kim Hyun-soo 1610-18, Mok-dong 7-gu, Gwanak-gu, Korea 100-402 Mukden 6-dong, Gwanak-gu, Seoul

Claims (10)

[Claims] 1. A liquid crystal display device obtained by bonding a substrate on which electrodes and an alignment layer are laminated to face each other, injecting a liquid crystal material between them, and sealing the liquid crystal display device. A liquid crystal display device comprising a polarizing layer formed by coating a dye having a concentration transition type liquid crystal phase on one side in one direction. 2. The liquid crystal display device according to claim 1, wherein the concentration transition type liquid crystal is a mixture of an amphiphilic compound and a polar solvent. 3. The liquid crystal display device according to claim 1, wherein the polarizing layer is melted at a temperature of 200 ° C. or higher. 4. The liquid crystal display device according to claim 1, wherein the thickness of the polarizing layer is formed in a range of 0.1 to 50 μm. 5. The liquid crystal display device according to claim 1, wherein a protective layer is further formed on the upper surface of the polarizing layer. 6. The liquid crystal display device according to claim 1, wherein the substrate is a glass or plastic film. 7. A step of coating one side of a substrate with a dye having a concentration transition type liquid crystal phase in one direction, and then drying to form a polarizing layer; and forming an upper surface of the polarizing layer or another surface of the substrate. A step of laminating an electrode and an alignment layer, and a step of bonding a pair of substrates so as to oppose each other so that the electrode patterns cross, injecting a liquid crystal material between them, and then sealing. Manufacturing method. 8. The method according to claim 7, wherein the thickness of the polarizing layer is formed in a range of 0.1 to 50 μm. 9. The method according to claim 7, further comprising the step of forming a protective layer on the upper surface of the polarizing layer. 10. A polarizing plate is formed as a final step after a pair of substrates on each of which an electrode and an alignment layer are laminated are opposed to each other, and a liquid crystal material is injected and sealed between them. A method for producing a liquid crystal display device according to claim 7.