JPS59176768A - Liquid crystal display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a liquid crystal display device having a light source that illuminates a liquid crystal display panel.

[Technical background of the invention]

Liquid crystal display devices can be broadly divided into two types. That is, there are two types: one is equipped with a light source that illuminates the liquid crystal display panel from the back side thereof, and the other is equipped with a light source that illuminates the liquid crystal display panel from the back side. A liquid crystal display device equipped with a light source is often used when the surroundings are dark because the display can be viewed regardless of the presence or absence of external light. An example of a conventional liquid crystal display device having a light source is shown in FIG. A light guide plate 4 is arranged on the substrate 1. A light source, for example, a plurality of light bulbs 3, is fixed on both ends of the substrate 1 with the light guide plate 4 in between, and on the outside of both ends there are lamps for reflecting the light from the light bulbs 3 toward the light guide plate 4. A reflecting plate 2 is arranged. Irregular plates 5 having a reflective function are arranged on both sides of the light guide plate 4 not facing the light bulb 3, and a liquid crystal display plate 6 is arranged above the light guide plate 4.

Note that the surface of the substrate 1 has a reflective function. The reflective function of the substrate 1 and the side plate 5 is obtained by forming a gold 8 film on their surfaces using means such as plating or vapor deposition.

[Problems with background technology]

Liquid crystal displays utilize polarization of liquid crystal materials. If you raise the temperature of the liquid crystal display board from room temperature, it will no longer be able to display anything above a certain temperature. This is because the liquid crystal material loses its properties as a liquid crystal and its polarization also disappears. The upper limit of the temperature range in which liquid crystal display is possible, that is, the operating temperature range, varies depending on the type of liquid crystal material, but is generally about 60 to 80°C. In the case of a liquid crystal display device equipped with a light source, heat generated from the light source is applied to the liquid crystal display board, causing the temperature of the liquid crystal display board to become higher than the surrounding temperature. Therefore, even if the upper limit of the operating temperature range is, for example, 80° C., the upper limit of the ambient temperature at which liquid crystal display can be performed is 80° C. or less.

In the conventional liquid crystal display device shown in the 11th threshold, the heat generated by the light bulb is difficult to be released to the outside due to the structure of the device, so the temperature around the light bulb 3 shows a large temperature rise, and a part of the liquid crystal display board 6 Temperatures can be as much as 50°C higher than

If the upper limit of the operating temperature range is 80°C, then the upper limit of the ambient temperature is 30°C. However, since liquid crystal display devices may actually be used at various environmental temperatures, it is desirable to set the upper limit of the environmental temperature at which liquid crystal display is possible as high as possible. To do this, the heat dissipation from the light source must be improved. A possible method to improve heat dissipation is to provide holes in the reflector plate 2, but this method has the disadvantage that light leaks directly to the outside and the amount of light irradiated to the liquid crystal display panel 6 is slightly reduced. There is. Thus, conventionally, it has been difficult to improve heat dissipation from the light source without reducing the amount of light irradiated onto the liquid crystal display panel.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned disadvantages, and an object of the present invention is to provide a liquid crystal display device having a structure in which heat generated by sunlight is not easily applied to the liquid crystal display panel.

[Summary of the invention]

A recess is provided in the heat dissipation member, and the inner wall thereof is used as a reflective surface. A light source is placed in this recess, and the liquid crystal display panel is irradiated with light emitted in front of the four parts.

[Embodiments of the invention]

The first embodiment of the present invention will now be explained with reference to FIG. N number of recesses 12 are formed in the heat dissipation member 11 made of gold wire, and the inner walls thereof serve as reflective surfaces.

This reflective surface can be obtained by mirror-finishing the surface of the concave portion or by coating it with a metal film. The light bulb 3 is in this recess 12
Inside is placed close to the wall. Other parts are first
Since it is similar to the figure, the same number is given and the explanation is omitted.

According to this embodiment, since the light bulb 3 is almost surrounded by the heat radiating member 11, the heat generated from the bulb 3 is efficiently radiated outside through the entire heat radiating member 11, which is a good conductor of heat.
Furthermore, the temperature rise of the liquid crystal display panel 6 can be suppressed to a low level.

Further, the heat dissipating member 11 is easy to manufacture because it is only necessary to form a hole with approximately the same external shape as the light bulb 3 in a columnar metal rod.

FIG. 3 shows a second embodiment of the invention. The light bulb 3 is placed in a recess formed in the heat radiating member 13.

Furthermore, a radiation fin 1\3' is attached to the opposite side of the recess. According to this embodiment, the surface area of the heat dissipation member 13 increases dramatically, so the heat dissipation efficiency becomes even better than in the first embodiment, and the upper limit of the ambient temperature at which liquid crystal display can be performed becomes much higher. .

In the above embodiment, a case is shown in which a plurality of light bulbs are used as a light source, but a fluorescent lamp, a cold cathode discharge tube, or the like may also be used as a light source.

〔Effect of the invention〕

According to the present invention, the heat generated by the light Im is efficiently released to the outside, making it possible to suppress the rise in temperature of the liquid crystal display and increase the upper limit of the ambient temperature at which the liquid crystal display can be performed. be able to. Moreover, even if the present invention is applied, the amount of light irradiated to the liquid crystal display panel does not decrease.

[Brief explanation of drawings]

Figures 1(a) and 2(b) are a vertical cross-sectional view and a horizontal cross-sectional view of a conventional liquid crystal display device, respectively, and Figures 2(a) and (b) are
l is an RI cross-sectional view and a cross-sectional view, respectively, of the first embodiment of the present invention, and FIGS. 3(a) and (b) are a longitudinal cross-sectional view and a cross-sectional view, respectively, of the second embodiment of the present invention. . 1.Substrate, 3.Light bulb, 4.Light guide plate, 6.Liquid crystal display board, 11.13..Heat radiation member, 13'.Radiation fin representative Patent attorney Kensuke Norichika (1 person or 1 person) 'f
t Figure (cLn(b) Complete 2 Figure (a) (b) 2

Claims (3)

[Claims] (1) a liquid crystal display board; a light source that illuminates the liquid crystal display board;
1. A liquid crystal display device comprising: a radiation member having a recess formed therein for accommodating the light source, the inner wall of the recess being a reflective surface. (2) The liquid crystal display device according to claim 1, wherein the heat radiation member is provided with a radiation fin. (3) The liquid crystal display device according to claim 1 or 2, wherein the heat radiating member is made of metal.