JPH05119314A - Illuminating device and liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide an illuminating device and a liquid crystal display device in which the unevenness of lightness on an irradiated surface is prevented. CONSTITUTION:When a fluorescent lamp 19 is turned on, a window material 24 on the side surface of a light transmission body 21 is irradiated with irradiating light. The light is wholly guided through a core material (light transmitting part) 22 and diffused toward an irradiating aperture part 13 by a diffusing material 23. An apparent light emitting surface is formed on a light diffusing and transmitting member 25, and the unevenness of the light is hardly caused on the member 25. Thus, a liquid crystal display body 26 is irradiated with uniform irradiating light from a back surface, so that the device is irradiated with the uniform irradiating light from the back surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device and a liquid crystal display device for making irradiation light uniform.

[0002]

2. Description of the Related Art Conventionally, there is known a backlight system in which light is emitted from the back surface of a liquid crystal display to illuminate the liquid crystal display.

In recent years, the backlight system has been
Widely used in consumer products, it is also used in office automation equipment. As the office automation equipment becomes lighter, thinner, shorter, and smaller, the backlight system is also required to have higher brightness, thinner shape, and lighter weight.

However, in the structure of the above-mentioned conventional backlight system, the brightness of the light emitting surface tends to be uneven.

Then, for example, Japanese Patent Laid-Open No. 64-11203
As disclosed in Japanese Patent Laid-Open Publication No. Heisei No. 2-143, a configuration is known in which a Fresnel-shaped plate is provided on the surface opposite to the aperture irradiation unit, or a lens is provided in front of the light source as described in Japanese Patent Laid-Open No. 52314/1990. .

[0006]

However, in the case of the structure described in Japanese Patent Laid-Open No. 64-11203, direct light from a light source and a Fresnel lens are used.
In the case of the configuration described in Japanese Patent No. 52314, there are problems that the configuration becomes complicated and the brightness of the light emitting surface cannot be made sufficiently uniform.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an illuminating device and a liquid crystal display device which prevent uneven brightness on the irradiation surface.

[0008]

According to a first aspect of the present invention, there is provided a lighting device including a base body having an irradiation opening formed therein, a light source disposed in the base body, and a light guide for guiding the irradiation light from the light source. The light guide and the light guide having a diffusion layer that is integrally formed on at least a surface of the light guide that faces the irradiation opening and that diffuses the irradiation light in the light guide.

According to a second aspect of the present invention, there is provided an illuminating device including a diffuser for diffusing the irradiation light on the front side of the light guide.

A liquid crystal display device according to a third aspect is the first aspect.
Alternatively, the liquid crystal display is provided on the front side of the lighting device described in 2.

[0011]

Since the illuminating device according to the first aspect uses the light guide body in which the light guide portion and the diffusion layer are integrally formed, it is possible to prevent the unevenness of the brightness generated on the irradiation surface with a simple structure.

According to a second aspect of the present invention, in the illumination device according to the first aspect, the light guide body is provided with a diffuser for diffusing the irradiation light on the front side thereof. It can be prevented.

A liquid crystal display device according to a third aspect is the first aspect.
Alternatively, since the liquid crystal display body is disposed on the front side of the lighting device described in the item 2, the liquid crystal display body does not have uneven brightness.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the liquid crystal display device of the present invention will be described with reference to FIGS.

In FIG. 1, reference numeral 11 denotes a rectangular base, and a holding portion 12 whose both ends are folded back in an arc shape is formed on the base 11, and a rectangular opening is formed between the holding portions 12 and 12. The irradiation opening 13 is formed. Inside the holding portions 12 at both ends of the base body 11, straight tube fluorescent lamps 14 having an outer diameter of 8 mm, which are linear light sources, are arranged, and are held by the holding portions 12. The shape of the holding portion 12 is formed in an arcuate curved surface that is substantially coaxial with the fluorescent lamp 14 so as to face the peripheral surface of the fluorescent lamp 14. Further, the inner surface of the base 11 is, for example, silver (Ag) or aluminum (A
The reflective surface 15 is formed by mirror-finishing with a vapor deposition coating such as l).

Further, on the reflecting surface 15 of the base 11, a light guide 21 having a flat plate shape whose side faces face the fluorescent lamp 14 and whose upper face faces the irradiation opening 13 is attached. This light guide
Reference numeral 21 denotes a fluororesin fiber, for example, a Ray Duck Light (trade name) manufactured by Bridgestone Corporation is attached. The light guide body 21 has a plate-shaped core material 22 that serves as a light guide portion in the center, and both surfaces of the core material 22 face the irradiation opening 13 and a diffusion surface that sandwiches the core material 22 on the back surface. A diffusing material 23 as a diffusing layer is attached. Further, a window material 24 as a transmitting surface is attached to the surface of the core material 22 facing the fluorescent lamp 14. Then, the irradiation light from the fluorescent lamp 14 enters through the window material 24, is guided by the core material 22, and is diffused by the diffusing material 23.

Further, a plate-shaped light diffusion / transmission member 25 as a diffuser for diffusing the irradiation light from the back surface is superposed so as to optically close the irradiation opening 13.

On the front surface of the light diffusing and transmitting member 25, a liquid crystal display 26 for displaying by liquid crystal is provided.

Next, the operation of this liquid crystal display device will be described.

First, when the fluorescent lamp 14 is turned on, the light guide
The window material 24 on the side surface of 21 is irradiated with irradiation light, and the core material 22 guides the entire light, and the diffusion material 23 diffuses the irradiation light toward the irradiation opening 13.
Then, an apparent light emitting surface is formed on the light diffusion / transmission member 25, and unevenness of light is unlikely to occur on the light diffusion / transmission member 25.

For this reason, the liquid crystal display 26 is also illuminated from the back side by the uniform irradiation light, so that it is illuminated from the back surface by the uniform irradiation light.

In the above embodiment, the light guide 21 is not limited to fluororesin, but frosted glass may be used.

Further, although the straight tube type fluorescent lamp 14 has been described, the fluorescent lamp 14 is not limited to the straight tube type, and the electrodes are sealed according to the shapes of the base 11 and the light emitting surface. A fluorescent lamp or the like in which the central axis of the end portion is inclined with respect to the central axis of the straight tube type glass bulb may be used, and the same effect can be obtained.

[0024]

According to the lighting device of the first aspect, since the light guide body integrally formed with the light guide portion and the diffusion layer is used,
With a simple structure, it is possible to prevent uneven brightness on the irradiation surface.

According to the illuminating device of the second aspect, in addition to the illuminating device of the first aspect, a diffuser for diffusing the irradiation light is provided on the front side of the light guide, so that the brightness generated on the irradiation surface is not affected. Uniformity can be prevented more.

According to the liquid crystal display device of the third aspect, since the liquid crystal display body is disposed on the front side of the illuminating device of the first or second aspect, it is possible to prevent uneven brightness of the liquid crystal display body.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a liquid crystal display device of an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the same.

[Explanation of symbols]

 11 Base 13 Irradiation Aperture 14 Fluorescent Lamp as Light Source 21 Light Guide 22 Core Material as Light Guide 23 Diffusing Material as Diffusion Layer 25 Light Diffusing and Transmissive Member as Light Guide 26 Liquid Crystal Display

Claims (3)

[Claims] 1. A base body having an irradiation opening formed therein, a light source disposed in the base body, a light guide section for guiding the irradiation light of the light source, and at least the irradiation opening section of the light guide section. And a light guide having a diffusion layer that is integrally formed on a surface facing the light guide and that diffuses the irradiation light in the light guide unit. 2. The illuminating device according to claim 1, further comprising a diffuser on the front side of the light guide, the diffuser diffusing the irradiation light. 3. A liquid crystal display device, wherein a liquid crystal display body is provided on the front side of the lighting device according to claim 1.