JPH0713141A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain a display element with bright display and excellent electric characteristics which can be easily produced by arranging a composite layer obtd. by laminating uniform liquid crystal layers and uniform plastic film layers between two electrode substrates at least one of which is transparent. CONSTITUTION:This liquid crystal element consists of transparent electrode substrates 3 with ITO and alternately laminated layers of four liquid crystal layers 1 and three polymethylmethacrylate films 2. The plastic film used is not especially specified, and for example, polymethylmethacrylate, polystyrene, etc., is used. Thickness of the plastic film is not specified as far as the film is transparent, and usually, 0.5mum-1mm, preferably 0.5-100mum and more preferably, 1-20mum. It is preferable that the film has uniform thickness. The liquid crystal used is not specified, and for example, azomethyne compd., azoxy compd, etc., is used.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A conventional liquid crystal display element uses at least one polarizing plate to polarize light and displays an image by changing the transmittance of incident light according to the electro-optical characteristics of liquid crystal by the action of an electric field. Used to switch or switch light.

For example, in a TN type liquid crystal display device, generally, a cholesteric liquid crystal is arranged in parallel between two polarizing plates to cut almost all incident light, and the liquid crystal is vertically aligned by the effect of an electric field to change the incident light. Make it transparent and transparent. Further, in the GH type liquid crystal display element, a dichroic dye whose alignment changes with the form or alignment of the liquid crystal is present in the liquid crystal, and transmitted light is colored by the dye arranged in the direction of light polarized through the polarizing plate. Then, the alignment of the liquid crystal is changed by the effect of the electric field, and the direction of the dye is changed, so that the polarized light is not absorbed but is transmitted as colorless light.

As described above, many liquid crystal display elements use at least one polarizing plate. Therefore, the display is dark.

[0005]

Unlike the above-mentioned TN-type and GH-type liquid crystal display devices, in a so-called polymer dispersion type liquid crystal in which a liquid crystal substance is finely dispersed in a polymer matrix, light generated by dispersion of the liquid crystal substance inside the dispersion is The transmission of light is controlled by the phenomenon that the light scattering disappears when the direction and size of the refractive index of the dispersion match the refractive index of the dispersion medium due to the orientation of the liquid crystal substance inside the dispersion due to the electric field effect. Therefore, it is not necessary to use a polarizing plate. Therefore, the liquid crystal display device using the polymer-dispersed liquid crystal can provide a brighter liquid crystal display than the liquid crystal display of the conventional normal liquid crystal display device.

However, the polymer-dispersed liquid crystal display device has a complicated structure such as difficulty in producing the average diameter and the distribution of the diameter of the dispersion with good reproducibility, and the reproducibility of the production is poor. Is difficult to make.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a liquid crystal display device which has a bright display because it does not need to use a polarizing plate, has excellent electro-optical characteristics, and is easy to manufacture. It is in.

[0008]

In the liquid crystal display device of the present invention, a uniform liquid crystal layer and a uniform plastic film layer are alternately laminated between at least two transparent electrode substrates. It is characterized in that a composite layer is arranged.

The liquid crystal display device of the present invention is excellent in that it is easy to manufacture.

The thickness of the plastic film layer of the present invention is not particularly limited as long as it is transparent, but it is usually 0.5 μm to 1 mm, preferably 0.5 to 1
The thickness is 00 μm, more preferably 1 to 20 μm. Further, it is desirable that the thickness of the film is uniform if possible.

The plastic film used is not particularly limited, but examples of the type of film include polymethylmethacrylate, polystyrene, styrene acrylonitrile copolymer, poly-4-methylpentene-1, polyethylene terephthalate, polyimide, polysulfone, and polysulfone. Examples thereof include ether sulfone, polyvinyl alcohol, polyethylene, polypropylene, polycarbonate, polyvinyl chloride, polyvinylidene chloride, and perfluoroelene / propylene copolymer.

In the present invention, the liquid crystal used is not particularly limited, and examples thereof include azomethine compounds, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexacarboxylic acid phenyl esters, cyanophenylcyclohexane, Nematic liquid crystals represented by cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxane, alkenylcyclohexylbenzonitrile and the like and mixtures thereof can be mentioned. Further, a dichroic dye may be added to the nematic liquid for the purpose of enhancing the contrast.

[0013]

EXAMPLE An example of the present invention will be described with reference to FIG. However, the following examples do not limit the present invention.

Example 1 In FIG. 1, reference numeral 1 is a liquid crystal layer made of E7 manufactured by Merck & Co. of Germany having a thickness of 5 μm, and 2 is a polymethylmethacrylate film having a thickness of 5 μm which has been rubbed.

The liquid crystal device of the present invention shown in FIG.
A transparent electrode substrate 3 with a TO, and four alternating liquid crystal layers 1 and three polymethylmethacrylate films 2
It consists of and.

While applying an AC voltage to the liquid crystal device of the present invention, a parallel light beam 4 having a wavelength of 550 nm was transmitted and the transmittance was measured. When the AC voltage was 0 V, the light transmittance was 2
%, 75% at 15 volts.

Comparative Example 1 4 grams of E7 manufactured by Merck & Co. of Germany used in Example 1 and a 10% by weight aqueous solution of polyvinyl alcohol (Poval 205 manufactured by Kuraray Co., Ltd.) were used in a four-bladed homogenizer. , Rotation speed 5,
The emulsion was obtained by stirring and dispersing at 000 rpm for 10 minutes.

This emulsion was applied to a glass substrate with a transparent electrode by a doctor blade having a gap of 60 μm,
Furthermore, it was left to stand in an environment of 20 ° C. and 40% RH for 24 hours and dried. Further, a glass substrate with a transparent electrode is attached as a counter electrode substrate to form a layer thickness 15 having a polymer dispersion type liquid crystal layer.
A μm liquid crystal cell was obtained.

An AC voltage of 50 Hz was applied to this liquid crystal cell, parallel rays of light having a wavelength of 555 nm were made incident, and the transmittance was measured. As a result, it was 70% at 70 V and 0.5% when the voltage was off.

[0020]

【The invention's effect】

1. The transmittance can be changed by adjusting the electric field without using a polarizing plate.

2. Unlike the polymer-dispersed liquid crystal, it is not necessary to adjust the dispersion liquid, and the liquid crystal layer can be easily adjusted.

3. A liquid crystal display device having a bright display and excellent electro-optical characteristics can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a liquid crystal display element of the present invention.

[Explanation of symbols]

 1 Liquid crystal layer 2 Polymer film 3 Transparent electrode substrate 4 Incident light

Claims (1)

[Claims] 1. A composite layer in which a uniform liquid crystal layer and a uniform plastic film layer are alternately laminated between two electrode substrates at least one of which is transparent. Liquid crystal display device.