JPH11213728A - Back lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the occurrence of luminance unevenness and reduce the thickness by arranging a cylindrical light source, and forming a diffuse reflecting layer on a reflecting layer between it and the inner bottom part of a lamp house. SOLUTION: A diffuse reflecting layer 4 is preferably formed of a while material, particularly, a film-like sheet or plate material. The diffuse reflecting layer 4 can be also formed by coating a lamp house 3. As the white material used herein, polyester is preferable. According to this structure, the light emitted from the inner bottom side of the lamp house 3 of a cylindrical light source 1 is diffused and reflected by the diffuse reflecting layer 4, so that a back lighting device with little luminance unevenness can be provided. More specifically, a film-like diffuse reflecting layer 4 about 0.2 mm thick consisting of white polyester is arranged on the inner bottom part of the lamp house 3 having a reflecting layer on the inside bottom part, whereby the luminance unevenness is improved, and the thickness can be reduced about 2 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various types of display devices, and more particularly, to a back illuminator for a word processor, a personal computer, a television and the like and a illuminator for a large liquid crystal display panel.

[0002]

2. Description of the Related Art Conventionally, in a rear illuminator using a cylindrical light source 1 such as a fluorescent tube, as shown in FIG. 4, direct light emitted from the cylindrical light source 1 and light reflected in a lamp house 3 are emitted. The light was incident on and diffused into the diffuser 2 to emit uniform planar light from its upper surface, and was used as a light source for a liquid crystal display panel.

[0003]

However, in the conventional rear illuminating device as shown in FIG.
Is merely arranged in a closed state at the opening of the lamp house 3, and when the light diffuser 2 is brought close to the cylindrical light source 1 in order to promote thinning, there is a disadvantage that uneven brightness occurs. there were.

The present invention has been made as a result of intensive studies to solve this problem. As shown in FIG. 1, a diffuse reflection layer 4 is formed on the reflection layer between the bottoms of the lamp house 3 so that the above-mentioned problem can be solved. The purpose is to eliminate the occurrence of uneven brightness and to reduce the thickness.

[0005]

According to the present invention, at least one or more cylindrical light sources 1 are arranged at the bottom of a flat lamp house 3 having a flat upper surface opening, and are arranged in a closed manner at the opening of the lamp house 3. In the rear illuminating device having the light diffuser 2, a thin rear illuminating device is provided by forming a diffuse reflection layer 4 on a reflection layer between the cylindrical light source 1 and the bottom of the lamp house 3.

By forming the diffuse reflection layer 4 of the present invention from a white material, in particular, a film-like sheet or plate-like material, a more excellent back-lighting device can be obtained. Also,
The diffuse reflection layer 4 can be formed by painting the lamp house 3. As the white material used here, polyester is preferably used.

[0007]

According to this configuration, the light emitted from the bottom of the cylindrical light source 1 inside the lamp house 3 is diffusely reflected by the diffuse reflection layer 4, so that a rear illuminating device with less luminance unevenness can be obtained.

[0008]

Embodiment 1 Hereinafter, a representative embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a screen size of 20 inches is adopted.
Denotes a light diffuser having a thickness of 2 mm, 3 denotes a lamp house having a reflective layer on the inner bottom, and 4 denotes a sheet-like diffuse reflective layer.

FIG. 1 is a perspective view in which a 0.2 mm-thick film-like diffuse reflection layer 4 made of white polyester is disposed on the bottom inside a lamp house 3 having a reflection layer on the inside bottom. By arranging the diffuse reflection layer 4, luminance unevenness is improved, and it is possible to reduce the thickness by 2 mm as compared with the related art.

[0010]

Embodiment 2 The diffuse reflection layer 4 shown in the sectional view of FIG.
mm of white acrylic resin. The use of the plate-shaped material facilitates the handling of the parts, and at the same time improves the strength of the lamp house 3.

[0011]

Embodiment 3 A diffuse reflection layer 4 shown in the sectional view of FIG. 3 was integrally formed on a lamp house 3 having a reflection layer on the inner bottom by painting.

[0012]

By providing the diffuse reflection layer 4 in the lamp house 3 having the reflection layer on the inner bottom portion, the unevenness of the luminance is reduced and the thickness of the entire rear lighting device can be reduced. Therefore, the large-sized back illuminating device can be made thin.

[Brief description of the drawings]

FIG. 1 is a perspective view of the rear illumination device of the present invention. FIG. 2 shows a sectional view of an embodiment of the present invention. FIG. 3 shows a sectional view of another embodiment of the present invention. FIG. 4 is a perspective view of a conventional rear lighting device.

[Explanation of symbols]

 Reference Signs List 1 cylindrical light source 2 light diffuser 3 lamp house 4 diffuse reflection layer

Claims (4)

[Claims] 1. A rear illuminating device having at least one or more cylindrical light sources disposed at the bottom of a flat lamp house having a top opening and a light diffuser arranged in a closed manner at the opening of the lamp house. A back illuminator, wherein a diffuse reflection layer is formed on the reflection layer between the cylindrical light source and the bottom of the lamp house. 2. A back illuminator according to claim 1, wherein the diffuse reflection layer is made of a white material. 3. A back illuminator according to claim 1, wherein the diffuse reflection layer is formed of a film-like material. 4. A back illuminator according to claim 1, wherein the diffuse reflection layer is made of a plate-like material.