JPS5852618A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To eliminat the difference of partial refractive index and reflectivity and to prevent color shading and lowering of contrast, by providing a thin film which consists of an insulating material having the same thermal coefficient of expansion as transparent electrodes further at the inner side of flexible polymer film substrates. CONSTITUTION:A common electrode 3 and a segment electrode 4 are provided with transparent conductive films such as indium oxide and tin oxide etc. at the inner side surfaces of the upper and lower substrates 1, 2 of flexible polymer films. These electrodes 3, 4 are arranged so as to be connected with an outside circuit through a lead electrode 5 and so that an electric field is applied. A thin film 6 which consists of an insulating material having almost the same thermal coefficient of expansion as that of the electrodes 3-5 is provided allover the surface at the substrates 1. 2. As such a thin film 6, e.g. TiO2 film, SiO2 film and Al2O3 film are used. Even if about 150 deg.C thermal stress is applied in a calcining process of manufacturing process of a liquid crystal display device, the generation of strain is prevented by an action of the thin film. The warpage of of polymer film substrates is eliminated and the gap between both substrates are kept uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display device. More specifically, the present invention relates to improvements in liquid crystal display devices using flexible polymer films as substrates.

A display panel installed in a conventionally known liquid crystal display device consists of two upper and lower substrates each made of inorganic glass or flexible polymer film, each provided with an electrode pattern, with the electrodes attached at a distance from each other with the surfaces facing inwards. After bonding with adhesive, both electrodes are connected vertically using a conductive member, a liquid crystal substance is sealed between the substrates, and a voltage is applied to the liquid crystal layer to change its optical properties.

It is designed to display characters, figures, etc. Among these, liquid crystal display devices that use flexible polymer films as substrates have the disadvantage that they are resistant to impact and can display curved surfaces.
Variations occurred on the display surface, and furthermore, the refractive index 1 reflectance was different in some parts, and color unevenness and contranuto reduction were likely to occur. The inventors investigated the cause and found that the polymer film itself, segment ill, common t[fM
, the coefficient of thermal expansion with transparent electrodes such as lead electrodes is 10 to 10.
It was found that when thermal stress is applied to a polymer film substrate, the substrate is distorted and unevenness occurs.

Therefore, the present inventors have completed the present invention as a result of continued research in order to eliminate the above-mentioned causes and to obtain a liquid crystal display device that does not have the above-mentioned drawbacks even though a flexible polymer film is used as a substrate.

In other words, the gist of the present invention is to arrange flexible polymer film substrates with transparent electrodes such as segment electrodes, common electrodes, and lead electrodes on the inside facing each other, and to seal liquid crystal between the two substrates so as to display characters, symbols, or figures. In a liquid crystal display device designed to display
Furthermore, the liquid crystal display device is characterized in that a transparent stain is provided with a thin film made of an insulating material having a coefficient of thermal expansion comparable to that of the electrode.

The present invention will be explained in detail below along with one embodiment (
1) (2+ is polybutylene terephthalate film,
Two substrates consisting of flexible polymer films such as polybutylene terephthalate film, telsulfone film, polycarbonate film and T'a
l = 1, which is a plate and is used in a facing arrangement.

The inner surfaces of the upper and lower substrates (11 + 21) are indium oxide.

A common electrode (3) and segment electrodes (4) are provided with a transparent conductive film such as tin oxide. These electrodes +
31 (4) is connected to an external circuit via a lead electrode (5) so that an 'rE field is applied to it.
A thin film (6) made of an insulating material having a coefficient of thermal expansion comparable to that of the electrodes is provided over the entire surface of the substrate (11 (21) on which transparent electrodes (3) (4) (!5) are provided. Here, the same coefficient of thermal expansion means that thin films (
6) indicates that the coefficient of thermal expansion is 1 to 9×10 ohters. As such a thin film (6), for example, Tie
, i exchange, Sin. Membrane, At, O. There are models, etc.
Tie2 can be made by, for example, dissolving TOT (tetraoctyl titanate) in a solvent, applying it and drying it.
The response speed of the known evaporated square crystal in2 film becomes slow. Further, as the thin film (6) component, a substance having an appropriate refractive index such as Al2O2 may be applied while adjusting the thickness to form an antireflection film. Then, an oriented film (7) made of saturated polyester alone or a mixture of saturated polyester and nylon is formed on the thin film (6), and on the oriented film (7) A gap material (8) consisting of resin particles is applied.The upper and lower substrates (11 (2+) are sealed in a stacked state using an adhesive I such as a silicone adhesive or an ultraviolet curing adhesive, or ultrasonic welding, etc.). A liquid crystal (9) is sealed in the resulting space, and a polarizing plate is superimposed on the outside of the upper and lower substrates (2).A reflecting plate may be further superimposed depending on the case.

As shown in IJ, the present invention provides a liquid crystal display device characterized in that a thin film made of an insulating material having a coefficient of thermal expansion comparable to that of the transparent electrode is provided above the transparent electrode inside the flexible polymer film cutting board. It is related to.

Therefore, a polymer film with a large coefficient of thermal expansion of about 7×1O 2 is covered with a transparent electrode with a small coefficient of thermal expansion of 7×10 2 and a thin film made of an insulating material with a coefficient of thermal expansion about the same. become. Therefore, during the baking process during the fabrication process of a faceted crystal display device, a heat source of about 150°C is used.
-Even if stress is applied, the occurrence of distortion is suppressed by the action of the thin layer 11Q.

In addition, since the polymer film substrate does not warp and the cap between both substrates can be held uniformly, variations in response speed can be reduced and local differences in refractive index and reflectance can be eliminated, resulting in uneven color. It is possible to prevent a decrease in contrast.

Example A common electrode and a segment electrode of IniOs were provided on the surface of a polyethylene terephthalate film substrate with a thickness of 100 μm, and then a layer of tetraoctyl titanate was applied to the entire surface.
Apply Nupinner with 0% ethyl alcohol/I/m solution and apply 1
A thin film is formed by baking at 50° C. for 1 hour. An alignment treatment film was formed thereon, a gap agent was further applied, two substrates were placed facing each other, and biphenyl liquid crystal was sealed between the substrates to produce a liquid crystal display device. With this device, there was no difference in local refractive index or reflectance (no color unevenness, no decrease in contrast, etc.)

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention. 1... ]: Punching board 2... Child board 3... Common electrode 1i 4... Segment electrode 5
・ ・ ・ Lead city ゛ (navigation 6 ° =
i-〆ha4-Agent Patent attorney Tsutomu Setatetsu (7) Figure 1

Claims (1)

[Claims] 1. Flexible polymer film substrates with transparent electrodes such as segment electrodes, common electrodes, lead electrodes, etc. arranged on the inside are arranged facing each other, 1. Liquid crystal is sealed between both substrates, and characters, symbols 2. In a liquid crystal display device that displays figures,
A liquid crystal display device, characterized in that a thin film made of an insulating material having a coefficient of thermal expansion comparable to that of the transparent electrode is further provided inside the thin polymer film substrate. 2. The liquid crystal display device according to claim 1, wherein the thin film is transparent. 3. A liquid crystal display device according to claim 1, wherein the thin film is provided on the lower substrate of the flexible polymer film substrate and is opaque.