JPH05313139A - Liquid crystal display device - Google Patents

Abstract

(57) [Abstract] [Purpose] The surface temperature of the backlight is higher the closer to the tube end of the CCFT. A surface heater is formed to offset this variation in the temperature distribution, and it is installed between the liquid crystal panel and the backlight to eliminate the variation in the temperature distribution of the liquid crystal panel. It eliminates the difference in optical characteristics and provides a uniform display quality image quality. [Structure] A transparent surface heater 2 is provided between a liquid crystal panel 1 and a backlight 3 so as to offset variations in the temperature distribution of the backlight.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A conventional liquid crystal display device will be described with reference to FIG. FIG. 2 is a sectional view showing an example of a conventional liquid crystal display device. 1, a liquid crystal panel, 3a a cold cathode tube (CCFT),
3b shows a light guide for diffusing and propagating light.

As shown in FIG. 2, the liquid crystal panel 1 is usually provided directly on the light guide 3b in order to maintain the mechanical strength of the entire liquid crystal display device.

[0004]

However, in the above-mentioned liquid crystal display device according to the prior art, the surface temperature of the backlight is higher as it is closer to the tube end of the CCFT. Here, since the liquid crystal panel is provided directly on the backlight, variations in the temperature distribution of the backlight are directly transmitted to the liquid crystal panel. Since the liquid crystal enclosed in the liquid crystal panel has a high thermal dependence, the variation in the temperature distribution causes a difference in the characteristics of the liquid crystal itself, which in turn causes a difference in the optical characteristics such as contrast and transmittance of the liquid crystal panel. . That is, there is a drawback that the display quality of the liquid crystal panel becomes non-uniform image quality.

Therefore, in order to solve the above-mentioned drawbacks, the present invention forms a surface heater that cancels the temperature distribution on the backlight surface caused by the heat generation of the CCFT, and a surface heater is provided between the backlight and the liquid crystal panel. It is provided to make the temperature distribution of the liquid crystal panel uniform. The purpose is to eliminate the differences in optical characteristics such as contrast and transmittance depending on the location of the liquid crystal panel, and to provide an image quality with uniform display quality.

[0006]

The liquid crystal display device of the present invention is a liquid crystal display device having a CCFT backlight, characterized in that a transparent surface heater is provided between the backlight and the liquid crystal panel.

[0007]

【Example】

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a sectional view of a first embodiment of the present invention, and FIG. 2 is a plan view showing a temperature distribution of a backlight and a surface heater of the first embodiment of the present invention. 1 is a liquid crystal panel, 2 is a transparent surface heater, 2a is a surface heater electrode, 3 is a backlight, 3Ca is a component of 3 and CCb is a light guide. The temperature distribution of the backlight 3 is shown in 3c.

In the first embodiment, the surface temperature of the backlight 3 is higher as it is closer to the tube end of the CCFT 3a and lower as it goes to the center of the backlight. On the backlight 3, there is provided a surface heater 2 in which an arbitrary number of crescent-shaped electrodes each having the thickest part have a constant width are formed so as to be closer to each other in the center of the liquid crystal panel. The heat transmitted to the liquid crystal panel 1 is approximately the sum of the heat generated by the backlight 3 and the heat generated by the transparent surface heater 2. Here, since the surface temperature of the backlight 3 and the surface temperature of the surface heater almost cancel each other, there is almost no variation in the temperature distribution of the liquid crystal panel 1 itself.

[0009]

As described above, according to the present invention, there is almost no variation in the surface temperature of the liquid crystal panel, so that the difference in optical characteristics such as contrast and transmittance depending on the location of the liquid crystal panel is eliminated, and the image quality with a uniform display quality is obtained. It has an excellent effect of being able to provide.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view showing a temperature distribution and a surface heater of the backlight according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional liquid crystal display device.

[Explanation of symbols]

 1. Liquid crystal panel 2. Surface heater 2a. Electrode 3. Backlight 3a. CCFT 3b. Light guide 3c. Temperature distribution

Claims (2)

[Claims] 1. A liquid crystal display device having a CCFT backlight, wherein a transparent surface heater is provided between the backlight and the liquid crystal panel. 2. The liquid crystal display device according to claim 1, wherein the surface heater is formed and arranged so as to cancel out the variation in the temperature distribution of the backlight caused by the heat generation of the CCFT.