JPH05173110A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain the large-screen liquid crystal display element having a high transmittance, high contrast, wide visual angle field, small size, light weight and high reliability by subjecting the surface of an org. high-polymer layer to be adhered to another layer to an electric discharge treatment, thereby improving adhesiveness of the surface of high polymer layer. CONSTITUTION:A uniform film 13a having, for example, 20mum total thickness is formed when an emulsion liquid layer 13 uniformly applied by a doctor blade method on a substrate 12 provided with transparent electrodes 11 is dried. The front surface of this film 13 is subjected to the corona discharge treatment at, for example, 80W.min/m<2>. A dry film 17 of 20mum thickness of the 2nd liquid crystal emulsion on another substrate 16 with similarly formed electrodes 15 is press welded onto the film 13 in superposition thereon to form the liquid crystal display element having the laminated org. high-polymer layer 18 of 40mum thickness held by the electrodes 11 and 15. The org. high-polymer layer 18 is formed of the structure constituted by using PVA as the high polymer of a base material 19 and dispersing liquid crystal grains 20 of about 3mum grain size therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a polymer type liquid crystal display device.

[0002]

2. Description of the Related Art TN type, ST, which is currently generally used
The N-type simple matrix drive liquid crystal display element and the active matrix drive display element have a cell structure in which liquid crystal is sandwiched between two glass substrates. This causes a problem that the liquid crystal display element becomes thick and becomes heavy when a large screen is displayed. Also, in the cell manufacturing process, after forming a transparent electrode or an active element for driving a liquid crystal on one glass substrate, a transparent electrode is formed on the other glass substrate,
After the alignment treatment is performed on each glass substrate, 2
A complicated cell manufacturing process that requires a long time, in which empty cells are formed by combining a plurality of glass substrates at regular intervals and then liquid crystal is injected, is followed. In addition, 2 polarizing plates
Since one sheet is used, the transmittance is low and the amount of light of the background illumination must be increased, and the power consumption is high and the power consumption is low, which reduces the advantage of the liquid crystal. The display principle also utilizes the optical rotation effect and the birefringence effect to obtain high contrast, but the display angle is very limited.

On the other hand, a polymer dispersed liquid crystal display device has a structure in which liquid crystal is finely dispersed in a porous resin, and since the liquid crystal can be held by the resin itself, a glass substrate is not always necessary and a thin liquid crystal display device is required. Can be realized, and a light liquid crystal display device can be realized even with a large screen. Further, since it is a liquid crystal display device in which light transmission and scattering are controlled by a voltage without using a polarizing plate, it has advantages of high light transmittance and wide viewing angle. However, there is a problem in that reliability is poor when the product is stored for a long time at high temperature or at high temperature and high humidity.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of a polymer dispersion type liquid crystal display device lacking reliability, and provides a simple and highly reliable method for producing a liquid crystal display device. It is a thing.

[0005]

The present invention provides a method for producing a liquid crystal display device, which comprises an organic polymer layer in which a liquid crystal is dispersed and which is sandwiched between a pair of opposing electrode layers, and at least one of the organic polymer layers is provided. Disclosed is a method for manufacturing a liquid crystal display element, characterized in that a surface to be bonded to another layer is subjected to an electric discharge treatment.

[0006]

[Function] The polymer liquid crystal display device includes an impregnation method in which a polymer porous body is impregnated with a liquid crystal, a liquid crystal is dispersed in an aqueous solution of a water-soluble polymer, and the dispersion is cast or cast onto a transparent electrode to remove moisture. Evaporate and then cover with another transparent electrode Emulsion method, Dissolve liquid crystal and polymer in a common solvent, then cast in the same way, Create a mixture of liquid crystal and monomer, polymerize monomer by heat or light It is manufactured by a polymerization method that obtains a phase separation structure of liquid crystal and polymer.

The polymer-dispersed liquid crystal display device manufactured by these methods is manufactured by applying a film-shaped organic polymer resin in which liquid crystal is dispersed to at least one of the indicator substrates with electrodes by pressure bonding and a polymerization chemical reaction. Create by gluing.

By the way, it has been found that when the surface of the organic polymer film in which the liquid crystal is dispersed is subjected to discharge treatment, the adhesiveness can be increased without deteriorating the surface performance. It is considered that this is because the surface was activated and the number of OH groups having high chemical reactivity increased. This improves the close contact and the adhesiveness between the films and the film and the electrodes, so that good durability can be obtained.

[0009]

Embodiment An embodiment of the present invention will be described below with reference to FIG.

Example 1 A liquid crystal and polyvinyl alcohol PVA were mixed, and this solution was further mixed with water and stirred to obtain a substantially uniform particle suspension size. As a result, a stable emulsion having a suspended particle size of about 3 μm was obtained. As shown in FIG. 1 (a), this emulsion was mixed with ITO.
Etc. are uniformly applied on the substrate 12 having the transparent electrode 11 attached thereto by using a doctor blade method. Obtained emulsion layer 13
Is about 200 μm thick. When this layer is dried, a uniform film 1 having a total thickness of about 20 μm as shown in FIG.
It became 3a. This film 13a is an organic polymer layer in which liquid crystal particles having a diameter of 3 μm are uniformly dispersed.

The surface of this film is 80 W.min / m
Corona discharge treatment was performed at ² (Fig. 1 (c)).

Then, a 20 μm-thick dry film 17 of the second liquid crystal emulsion on a substrate 16 with another electrode 15 formed in the same manner is overlaid on the film 13a and pressure-bonded (see FIG. 1).
(D)), a liquid crystal display element having a laminated organic polymer layer 18 having a thickness of 40 μm sandwiched between the electrodes 11 and 15 is formed as shown in FIG. The organic polymer layer 18 is made of PVA as a polymer.
Is used as a base material 19 and liquid crystal particles 20 having a particle diameter of about 3 μm are dispersed.

The substrates 12 and 16 are provided for mechanical holding of the element and can be made of transparent resin. In this embodiment, the thickness of the entire element is 2 mm and the weight is 20 g. Was given.

When the device thus obtained was turned on,
Display contrast 10: 1, viewing angle 80 ° cone,
With a transmittance of 60%, it was possible to display a clear image with high transmittance, high contrast and a wide field of view.

When this liquid crystal display device was kept in an oven at 80 ° C. for 200 hours, there was no change in appearance and optical characteristics.

[Embodiment 2] In Embodiment 1, a three-terminal element using a TFT as an active element for driving a liquid crystal is formed on a substrate, and an emulsion of liquid crystal and resin is applied in the same manner as in Embodiment 1. Dried to form a uniform film. A corona discharge treatment is applied to the film surface, and a transparent resin substrate coated with a second ITO electrode is pressed onto the film so that this electrode contacts the discharge treated surface of the emulsion film to form a liquid crystal display element. did. The produced liquid crystal display element including the substrate was thin and lightweight, having a thickness of 2 mm and a weight of 22 g. When this was turned on, there were no pixel defects, the display contrast was as high as 10: 1, the viewing angle was 75 ° cone, and the transmittance was 55%. The display image had good transmittance, contrast, and viewing angle.

When this liquid crystal display device was kept in an oven at 80 ° C. for 200 hours, no change was observed in its appearance and optical characteristics.

[Comparative Example 1] In Example 1, a liquid crystal display element was formed by laminating the adhesive surface of the film 13a without performing discharge treatment. The electrical characteristics and optical characteristics after manufacturing were the same as those in the example, but the temperature was 200 ° C in an oven at 80 ° C.
After holding for a while, peeling failure occurred in several places in the element,
As a result, defective foaming occurred.

[Example 3] In Example 1, after the adhesive surface of the film 13a was subjected to discharge treatment (Fig. 1C), the substrate 16 on which the film layer 17 was not formed in Fig. 1D.
The surface of the electrode 15 was directly bonded to the surface of the film 13a to form a liquid crystal display element. The thickness of the liquid crystal display element is 2
mm, the weight was 20 g.

When this liquid crystal display device was turned on, the display contrast was 11: 1, the viewing angle was 80 ° cone,
A high image display with a high transmittance of 60% was obtained. This element was kept in an oven at 80 ° C for 200 hours,
There was no change in its appearance or optical characteristics.

When the surface of the electrode 15 is subjected to electric discharge, the adhesive force can be further increased and the reliability can be improved.

Comparative Example 2 A display element was formed in the process of Example 3 without performing corona discharge treatment on 13a of Example 3. When this device was turned on, the display contrast was 11: 1, the viewing angle was 80 ° cone, and the transmittance was 60%, which were the same as those in Example 3, but in an oven at 80 ° C, 20
When it was held for 0 hour, peeling failure at several places and foaming failure due to it occurred. It is considered that this is due to deterioration of the electrode surface due to foaming due to electrolysis or moisture absorption due to poor adhesion.

[0023]

According to the present invention, the adhesion of the organic polymer layer surface to other organic polymer layers or electrode layers is improved, and high transmittance, high contrast, wide viewing angle, thin and lightweight, and high reliability. A screen liquid crystal display device can be obtained by a simple manufacturing process.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an element showing a manufacturing process of an embodiment of the present invention.

[Explanation of symbols]

 11, 15 ... Transparent electrode, 12, 16 ... Substrate, 13 ... Emulsion layer, 13a, 17 ... Film (organic polymer layer), 18 ... Organic polymer layer 19 ... Liquid crystal grain

Claims (1)

[Claims] 1. A method of manufacturing a liquid crystal display device comprising an organic polymer layer in which a liquid crystal is dispersed sandwiched between a pair of opposing electrode layers, a surface to be bonded to at least one other layer of the organic polymer layer. A method for manufacturing a liquid crystal display element, characterized in that