JPH08320475A - Liquid crystal display element - Google Patents

Abstract

PURPOSE: To provide a liquid crystal display element having high reliability of adhesion strength between a substrate and a polarizing plate. CONSTITUTION: The liquid crystal display element 1 consists of an upper polarizing plate 11, lower polarizing plate 12, polymer film 13 having double refraction property, and liquid crystal cell 14. The liquid crystal cell 14 is produced by disposing an upper substrate 23 and a lower substrate 24 comprising transparent plastic films having electrode layers 21, 22 formed, and holding a nematic liquid crystal layer 25 between the substrates. Further, the surfaces of the upper substrate 23 and the lower substrate 24 opposite to the contact surfaces to the nematic liquid crystal layer 25 are subjected to corona discharge treatment.

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, and more particularly to a liquid crystal display device having a highly reliable adhesive strength between a polarizing plate and a substrate.

[0002]

2. Description of the Related Art A liquid crystal display device has a large screen display due to the development of an STN (super twist nematic) system in which a nematic liquid crystal layer is twisted between 180 ° and 360 ° between two electrode substrates. It has become possible and is widely used not only as a display for clocks and calculators but also as a display for OA equipment and information equipment terminals.

The liquid crystal display element basically has a structure in which a liquid crystal cell is sandwiched between a pair of polarizing plates. Hereinafter, the configuration will be described with reference to FIG. In FIG. 2, the liquid crystal cell 53 arranged between the upper polarizing plate 51 and the lower polarizing plate 52 is such that a transparent upper substrate 54 and a lower substrate 55 are arranged to face each other, and both of these substrates 54, 55
Thus, the nematic liquid crystal layer 56 is sandwiched. In FIG. 2, reference numeral 61 denotes both substrates 54 and 55.
Spacers 62 for keeping the distance between them constant, and a seal material 62.

Recently, a lighter weight liquid crystal display device has been demanded, and a plastic film has been used as a substrate material.

[0005]

However, in the above conventional structure, when a plastic film is used as the substrate and the plastic film has poor wettability, good adhesion between the polarizing plate and the substrate cannot be obtained. Therefore, there is a problem that the reliability of the adhesive strength cannot be secured.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a liquid crystal display device having high reliability of the adhesive strength between a polarizing plate and a substrate.

[0007]

In order to solve the above-mentioned problems, a liquid crystal display device of the present invention has a twisted orientation between two transparent substrates which are sandwiched by a pair of polarizing plates and which are arranged opposite to each other. A liquid crystal display element formed by sandwiching a nematic liquid crystal layer, wherein at least one substrate is a plastic film, and the surface of the plastic film opposite to the surface sandwiching the liquid crystal layer is subjected to discharge treatment. .

Further, in the above liquid crystal display device, a polymer film having birefringence is arranged between the polarizing plate and the substrate.

[0009]

According to the above structure, when the substrate formed of the plastic film is subjected to the electric discharge treatment, the surface of the substrate is activated and the adhesive force is increased, and therefore the reliability of the adhesive strength between the polarizing plate and the substrate is improved. The nature is enhanced.

Further, in the above liquid crystal display device, since the polymer film having birefringence is arranged between the polarizing plate and the substrate, it is possible to eliminate the coloring of the display and improve the display quality.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal display device according to an embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the liquid crystal display element 1 is composed of an upper polarizing plate 11, a lower polarizing plate 12, a polymer film 13 having birefringence, and a liquid crystal cell 14. The liquid crystal cell 14 is arranged between the upper and lower polarizing plates 11 and 12 via the polymer film 13, respectively.

In the liquid crystal cell 14, an upper substrate 23 and a lower substrate 24, which are made of a transparent and isotropic plastic film on which the electrode layers 21 and 22 are formed, are arranged to face each other. Both of these substrates 23,
A nematic liquid crystal layer 25 having a twisted orientation is sandwiched between 24.

The upper substrate 23 and the lower substrate 24 are
The spacers 26 and the sealing material 27, which are uniformly arranged, keep them at regular intervals. Then, the upper substrate 2
3 and the surface of the lower substrate 24 opposite to the surface sandwiching the nematic liquid crystal layer 25 are subjected to discharge treatment. This discharge treatment is performed by corona discharge treatment.

When the liquid crystal display element 1 according to this embodiment described above and the conventional liquid crystal display element were left in an environment of 40 ° C. and 95% RH for 500 hours, the polarizing plate in the conventional liquid crystal display element was a substrate. However, in the liquid crystal display element 1 according to the present embodiment, the liquid crystal display element 1 is not peeled off, and therefore the reliability of the adhesive strength between the polarizing plate and the substrate is high.

As described above, according to this embodiment, the upper substrate 23
By performing discharge processing on the surface of the lower substrate 24 opposite to the surface sandwiching the nematic liquid crystal layer 25, the reliability of the adhesive strength between the polarizing plate and the substrate can be improved. In addition, the liquid crystal cell 14 and each polarizing plate 1
The birefringent polymer film disposed between the first and the second layers suppresses coloring of transmitted light and realizes good black and white display. That is, the coloring of the display can be eliminated, and the display quality can be improved.

[0016]

As described above, according to the structure of the present invention, the reliability of the adhesive strength between the polarizing plate and the substrate can be increased by subjecting the substrate made of the plastic film to the electric discharge treatment. It is possible to provide a lightweight and highly reliable liquid crystal display element.

Further, since the polymer film having birefringence is arranged between the polarizing plate and the substrate, the coloring of transmitted light is suppressed, that is, the coloring of the display can be eliminated and the display quality is improved. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an internal configuration of a liquid crystal display element according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an internal configuration of a liquid crystal display element in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 11 Upper polarizing plate 12 Lower polarizing plate 13 Polymer film 14 Liquid crystal cell 21, 22 Electrode layer 23 Upper substrate 24 Lower substrate 25 Nematic liquid crystal layer

Claims (3)

[Claims] 1. A liquid crystal display device comprising a pair of polarizing plates, and a nematic liquid crystal layer having a twisted orientation sandwiched between two transparent substrates arranged to face each other.
At least one substrate is a plastic film,
A liquid crystal display device characterized in that the surface of the plastic film opposite to the surface holding the liquid crystal layer is subjected to electric discharge treatment. 2. The liquid crystal display element according to claim 1, wherein a corona discharge treatment is performed as the discharge treatment. 3. A liquid crystal display device according to claim 1, wherein a polymer film having birefringence is arranged between the polarizing plate and the substrate.