JPH02302725A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve the narrowness of the angle of visibility by setting a diffusing plate whose ratio of diffuse transmission factor to total light transmittivity is >=40% on the outside of a polarizing plate on a side where a liquid crystal display device is observed. CONSTITUTION:In the liquid crystal display device consisting of a liquid crystal panel which holds liquid crystal 5 between two opposed substrates 3 having electrodes in the inner surfaces and two polarizing plates 2 which sandwich the panel, the diffusing plate 1 whose ratio of the diffuse transmission factor to the total light transmittivity is >=40% is set on the outside of the polarizing plate 2 on the side where the liquid crystal display device is observed. In the case, etching glass having an optional value, if its haze factor is >=40%, can be used instead of the resin diffusing plate 1 and not only one-side etching glass but also both-side etching glass can be used. Thus, the narrowness of the angle of visibility which is the trouble of the liquid crystal display device is improved.

Description

[Detailed description of the invention] (Industrial application field 1 The present invention relates to a liquid crystal display device.

[Prior Art] Liquid crystal display devices have been increasing in size for use in personal computers, word processors, etc., riding on the trend of becoming lighter, thinner, shorter, and smaller.

However, the narrow viewing angle is an impediment to the development of this technology, and although this has been considerably improved with the super twist nematic (STN) technology in recent years, color changes still occur as the viewing angle becomes smaller. Sufficient characteristics were not always obtained, such as the display being violent or the positive display and negative display being reversed.

[Problem to be Solved by the Invention 1] Therefore, an object of the present invention is to provide a liquid crystal display device that improves the narrow viewing angle, which is a problem of the prior art described above.

[Means for Solving the Problems 1] A first liquid crystal display device of the present invention includes at least a liquid crystal panel in which a liquid crystal is sandwiched between two opposing substrates having electrodes on the inner surface to which a voltage can be applied from the outside; In a liquid crystal display device consisting of two polarizing plates sandwiching the panel, a diffuser having a ratio of diffuse transmittance to total light transmittance of 40% or more is provided on the outside of the polarizing plates on the side where the liquid crystal display device is viewed. It is characterized by the installation of a board.

A second liquid crystal display device of the present invention is characterized in that the outer surface of the polarizing plate on the viewing side of the liquid crystal display device is subjected to a diffusion treatment in which the ratio of diffuse transmittance to total light transmittance is 40% or more. shall be.

[Example] Hereinafter, the present invention will be explained in detail in Examples.

Note that the haze rate described below is (diffuse transmittance/total light transmittance) X'lOO.

<Example 1> FIG. 1 is a sectional view of a liquid crystal display device shown in Example 1.

Figure 2 shows the 180° twist 1/200 in Example 1.
This is the left and right viewing angle characteristics of contrast in duty-driven birefringence positive display.

The liquid crystal display device of this embodiment was constructed by installing a resin diffuser plate l on the surface closest to the viewer of the liquid crystal display device, which consists of a glass substrate 3, a sealing material 4, a liquid crystal 5, and two upper and lower polarizing plates 2. . As a resin diffuser plate, it was possible to use one with any optical value with a haze rate of 40% or more, but in Fig. 2, a resin diffuser plate with a total light transmittance of 60% and a diffuse transmittance of 50% (haze rate of 83%) was used. Viewing angle characteristic 7 when a plastic diffuser is used and viewing angle characteristic 6 when a resin diffuser plate 1 is not installed are shown. There was almost no coloration (color change) characteristic of the birefringence mode, and the color was almost the same no matter where you looked from.

In addition, it is not necessary that the resin diffuser's Heis ratio be at the same level at all viewing angles; it goes without saying that it would be more effective to have a material that diffuses as little as possible at the front and has excellent diffusivity at low viewing angles. .

<Example 2> In Example 1, etching glass was used instead of the resin diffuser plate 1 to produce a liquid crystal display device.

Etching glass of any value can be used as long as the haze rate is 40% or more, and single-sided etching or double-sided etching is also possible. Figure 3 shows the viewing angle dependence of contrast when using single-sided etched glass with a haze rate of 50%.8 In the case of etched glass, there is almost no loss in total light transmittance, so there is almost no decrease in front contrast. However, the same effect as in Example 1 was obtained.

<Example 3> Instead of the resin diffuser plate in Example 1, the outer surface of the polarizing plate 1 was coated with an acrylic resin containing TiO□ particles. Similarly to Example 1, a liquid crystal display device with a wide viewing angle range was created.

<Example 4> Instead of using the resinous diffuser plate in Example 1, the outer surface of the film constituting the polarizing plate 1 was disturbed with a heated roller to perform a diffusion treatment. As in Example 1, a liquid crystal display device with a wide viewing angle range was produced.

〔Effect of the invention〕

According to the present invention, the narrow viewing angle, which has been a hindrance to the market development of liquid crystal display devices, can be significantly improved, making it an extremely effective invention.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a liquid crystal display device in Example 1 of the present invention. FIG. 2 is a diagram showing contrast-viewing angle characteristics of the liquid crystal display device shown in Example 1 of the present invention. FIG. 3 is a diagram showing contrast-viewing angle characteristics of a liquid crystal display device according to Example 2 of the present invention. l...Diffusion plate 2...Polarizing plate 3...Glass substrate 4...Sealing material 5...Liquid crystal or above Observer C, R. Figure 2 C, R. Figure 3

Claims (2)

[Claims] (1) In a liquid crystal display device consisting of at least a liquid crystal panel in which liquid crystal is sandwiched between two opposing substrates having electrodes on the inner surface to which a voltage can be applied from the outside, and two polarizing plates sandwiching the panel, The ratio of diffuse transmittance to total light transmittance is 40% on the outside of the polarizing plate on the side where the liquid crystal display device is observed.
A liquid crystal display device characterized by installing the above-mentioned diffusion plate. (2) A liquid crystal display device characterized in that the outer surface of the polarizing plate on the viewing side of the liquid crystal display device is subjected to a diffusion treatment such that the ratio of diffuse transmittance to total light transmittance is 40% or more.