JPH0792464A - Back light for liquid crystal display device - Google Patents

Abstract

PURPOSE:To enhance the utilization efficiency of the light of a light source and to make the radiation of the light of uniform luminance possible, without complicating a working process by providing a housing part in the vicinity of the end part of a light transmission plate and installing the light source inside the housing part. CONSTITUTION:The light transmission plate 12 having the formation of a reflection plate 11 on a back surface and first/second diffusion plates 13 and 14 on the surface and the light source 16 are provided, the housing part 15 is provided in the vicinity of the end part of the light transmission plate 12 and the light source 16 is arranged in the housing part 15. Further, the right surface R of the right housing part 15 and the left surface R of the left housing part 15 are mirror finished and the light radiating outside is efficiency reflected on the center of the light transmission plate. Moreover, the reflection plate 11, the light transmission plate 12 and the diffusion plates 13 and 14 are punched by a die so as to enter into the light source. However, when either of the reflection plate 11 or the diffusion plates 13 and 14 are punched, the light source can be easily housed so that it is unnecessary that all of them are punched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight for a liquid crystal display device, and more particularly to improvement of light utilization efficiency of the backlight for a liquid crystal display device used as a light source of the liquid crystal display device. Recently, for example, pagers,
A backlight for a small liquid crystal display device applied to a facsimile or the like is required.

[0002]

2. Description of the Related Art A conventional backlight for a liquid crystal display device will be described below with reference to the drawings. FIG. 3 is a top view of a first backlight for a liquid crystal display device according to a conventional example, and FIG. 4 is a sectional view taken along line BB of FIG.

As shown in FIG. 3, a backlight for a liquid crystal display device according to a conventional example has two light sources (2) composed of cold cathode tubes on both sides of a light guide plate (1) composed of acrylic or the like.
It was configured to be provided one by one. In the device, the light emitted from the light source (2) spreads while being reflected inside the light guide plate (1), and the light is emitted from the entire surface of the light guide plate (1), thereby acting as a backlight of the liquid crystal display device. Was.

[0004]

However, in the backlight for a liquid crystal display device according to the conventional example, the light emitted from the light source (2) is emitted as shown in FIG. Of the light guide plate (1) as shown in FIG.
However, there is a problem that the light emitted from the area becomes weak and uneven brightness occurs on the screen.

For example, if a light source having two light sources shown in FIG. 3 and a length of 30 mm and a diameter of 0.75 mm can be realized, the uneven brightness can be eliminated. However, this light source has a drawback that it is virtually impossible to pull a vacuum glass tube or the like straight into a cylindrical shape, and even if it is possible, a cost problem arises. Therefore, in order to solve this problem, as shown in FIG. 5, the light source (6) is covered with a reflective film (7) made of silver or the like, so that the light emitted from the light source (6) is enhanced and a blind spot is not generated. There have been proposed a device for doing so and a device for preventing a blind spot of light in the light guide plate by embedding a light source inside the light guide plate. 6 is a sectional view taken along the line CC of FIG.

However, since the reflection film (7) made of silver or the like is used in the above apparatus, since the light source itself is small, the work steps for installing it are complicated and the reflection film (7) becomes complicated. There is a problem in that the cost itself is high, and in the other device, there is a problem in that it is technically very difficult to embed the light source in the light guide plate.

[0007]

The present invention has been made in view of the above-mentioned drawbacks of the prior art. As shown in FIG. 1, a reflecting plate (11) is formed on the back surface and first and second reflecting surfaces are formed on the front surface. Diffuser (1
3, 14) and a light guide plate (12) and a light source (1
6), a storage part (15) is provided in the vicinity of the end of the light guide plate (12), and the light source (16) is installed inside the storage part (15). Provided is a backlight for a liquid crystal display device, which is capable of increasing the utilization efficiency of light from a light source and radiating light of uniform brightness to the entire device while suppressing the complexity and cost of the work process. It is a thing.

[0008]

[Operation] According to the backlight for a liquid crystal display device of the present invention, as shown in FIG. 1, a storage portion (15) is provided near the end of the light guide plate (12), and the light source (16) is It is installed inside the storage part (15). Therefore, unlike the conventional device shown in FIG. 3, since it is not necessary to form the reflection film after the light source, the work process required for the formation can be omitted, and the cost can be reduced by the amount of the reflection film. Further, unlike the conventional device, it does not require a difficult work such as embedding a light source in the light guide plate, so that it is possible to improve the utilization efficiency of the light of the light source without complicating the working process. Therefore, it is possible to emit light with uniform brightness.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A backlight of a liquid crystal display device according to an embodiment of the present invention will be described below with reference to the drawings. 1 is a top view of a backlight for a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG.

As shown in FIG. 1, a backlight for a liquid crystal display device according to a conventional example has a film thickness of 1 made of acrylic or the like on a reflection plate (11) having a width of 61 × a length of 33.7 mm and a film thickness of 0.188 mm. A light guide plate (12) having a thickness of 0.2 mm is formed on the first and second diffusion plates (13, 1) made of a polyester-based material having a film thickness of 0.14 mm for suppressing uneven brightness.
4) are sequentially formed.

A groove (15), which is an example of a housing, is provided at a position 1 mm inside from both ends of the light guide plate (12). The groove (15) has a diameter of 0.75 mm and a length of 3 mm. A different light source (16) is installed in this groove (15).
Further, on the side surface of the backlight, a white polyester film (not shown) that reflects light and enhances light utilization efficiency is formed.

Moreover, the right side surface (R) of the right storage section (15) and the left side surface (R) of the left storage section (15) are mirror-finished so that the light emitted to the outside is efficiently guided. The light is reflected in the center of the light plate. Further, as shown in FIG. 2, a reflection plate (11), a light guide plate (11) and a diffusion plate (1
3) and (14) are punched with a mold so that the light source enters. However, if either the reflector or the diffuser is punched out, the light source can be simply stored, so it is not necessary to punch out all. However, there is a problem that the heat generated from the light source cannot be satisfactorily released to the outside as compared with FIG.

Therefore, as shown in the figure, the light source (16)
The light emitted from the light spreads all over the light guide plate (12),
Unlike the conventional device of FIG. 3, light does not have a blind spot and does not have a dark area (DD), so that it is possible to emit light of uniform brightness. As a result, unlike the conventional device shown in FIG. 5, it is possible to omit the work steps for forming the reflective film, and the cost can be reduced by the amount of the reflective film. Since the difficult work of burying the light source in the light guide plate is not required, the work process is not complicated.

Therefore, it is possible to increase the efficiency of using the light of the light source and to radiate the light of uniform brightness by an easy process of forming the groove, and even if the size and thickness of the device are reduced,
It is possible to deal with it sufficiently.

[0015]

As described above, according to the backlight of the liquid crystal display device of the present invention, the housing portion (15) is provided near the end of the light guide plate (12), and the light source (16) is
Since it is installed inside the storage part (15), the work process for forming the reflective film can be omitted, and the cost can be reduced by the amount of the reflective film. Therefore, the efficiency of using the light from the light source is increased without complicating the work process,
It becomes possible to emit light of uniform brightness.

[Brief description of drawings]

FIG. 1 is a top view of a backlight for a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a backlight for a liquid crystal display device according to an embodiment of the present invention.

FIG. 3 is a top view of a first liquid crystal display backlight according to a conventional example.

FIG. 4 is a sectional view of a first backlight for a liquid crystal display device according to a conventional example.

FIG. 5 is a top view of a second backlight for a liquid crystal display device according to a conventional example.

FIG. 6 is a cross-sectional view of a second backlight for a liquid crystal display device according to a conventional example.

[Explanation of symbols]

 (11) Reflector (12) Light guide (13) First diffuser (14) Second diffuser (15) Groove (storage) (16) Light source

Claims (3)

[Claims] 1. A light guide plate having a reflection plate formed on a back surface thereof and a diffusion plate formed on a surface thereof, and a light source, and a storage portion is provided near an end portion of the light guide plate. A backlight for a liquid crystal display device, characterized by being installed inside a storage part. 2. A light guide plate having a reflection plate formed on the back surface and a diffusion plate formed on the front surface, and a light source, and storage parts are provided near both ends of the light guide plate. A backlight for a liquid crystal display device, wherein an inner side surface of the storage section, which is installed inside the section and corresponds to an end side of the light guide plate facing the installed light source, is mirror-finished. 3. A light guide plate for transmitting light, a reflection plate provided on the back surface of the light guide plate, a diffusion plate provided on the surface of the light guide plate, and provided at least in the vicinity of an end portion of the light guide plate. A backlight for a liquid crystal display device, comprising at least a storage section and a light source provided in the storage section, wherein a reflection section in which the inner surface of the storage section on the end side of the light guide plate facing the light source is mirror-finished. And a reflection part provided on four side surfaces of the light guide plate.