JPH05107540A - Illuminating device and liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device where light efficiency is improved and the unevenness of brightness occurring on an irradiating surface is prevented. CONSTITUTION:When a fluorescent lamp 14 is lighted, a light transmission body 21 is irradiated with light. The light transmission body 21 transmits the irradiating light from the lamp 14 and the light transmission body 21 itself gets bright, then it irradiates toward an irradiating aperture part 13 in a plane state. The irradiating light from the lamp 14 to just above the lamp 14 is lowered most by the dot pattern 23 of the back surface of a light diffusion transmissive member 22 and the lowering of the irradiating light is made small as it goes away from the lamp 14. The unevenness of brightness is not caused on the light diffusion transmissive member 22. Therefore, a liquid crystal display body 24 is also irradiated from the back surface with the uniform irradiating light, so that display is performed with the uniform irradiating light.

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 the irradiation light on an irradiation surface 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.

There is known a structure in which light sources are arranged at both ends of a base and irradiation is performed from both ends of the base toward the center, as described in, for example, JP-A-2-52314.

[0006]

However, in the case of the structure described in Japanese Patent Application Laid-Open No. 2-52314, when the light source irradiates from both ends of the base toward the center, the surface of the base end of the light source on the end side is exposed. There are problems that light emission is wasted, light efficiency is reduced, 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 improve the light efficiency and prevent the unevenness of the brightness generated on the irradiation surface.

[0008]

According to a first aspect of the present invention, there is provided an illumination device, wherein a base body having an irradiation opening is formed, a light source disposed in the base, and the irradiation opening facing the base. And a light guide body sandwiching the light source.

An illumination device according to a second aspect of the present invention is the illumination device according to the first aspect, further comprising a diffuser that optically closes the irradiation opening and diffuses the irradiation light.

According to the third aspect of the present invention, the illuminating device has a dot pattern for light control on the back surface of the diffuser, which has a high density on the light source and a lower density as the distance from the light source increases.

A liquid crystal display device according to a fourth aspect is the first aspect.
The liquid crystal display is arranged on the front side of the lighting device described in any one of 3 to 3.

[0012]

In the illuminating device according to the first aspect of the invention, since the light guide body for sandwiching the light source is arranged in the base so as to face the irradiation opening, the efficiency of the irradiation light from the light source is improved and the irradiation surface is improved. Prevents uneven brightness that occurs in.

According to a second aspect of the present invention, in the illumination apparatus according to the first aspect, the diffuser optically closes the irradiation opening and diffuses the irradiation light. To prevent more.

According to the third aspect of the present invention, since the back surface of the diffuser has a dot pattern for light control, which has a high density on the light source and a lower density as the distance from the light source increases, the lamp image can be made small. it can.

A liquid crystal display device according to a fourth aspect is the first aspect.
Since the liquid crystal display is disposed on the front side of the lighting device described in any one of the items 1 to 3, the liquid crystal display does not have uneven brightness.

[0016]

1 shows a first embodiment of the liquid crystal display device of the present invention.
And it demonstrates with reference to FIG.

In FIG. 1, reference numeral 11 denotes a rectangular base body, and an end portion 12 whose both ends are folded back in an arc shape is formed in the base body 11, and a rectangular opening is formed between the end portions 12, 12. The irradiation opening 13 is formed. The ends 12, 12 of this base 11
Straight tube fluorescent lamps 14 having an outer diameter of 8 mm, which are linear light sources, are arranged in the respective one-thirds of the spaces. Further, the inner surface of the base 11 is mirror-finished by a vapor deposition coating of silver (Ag) or aluminum (Al) to form a reflecting surface 15.

Further, a fluorescent lamp on the reflecting surface 15 of the substrate 11
On both sides of the fluorescent lamp 14, two prismatic prismatic light guides 21, 21 made of, for example, acrylic, each having a height slightly lower than the height of the base 11, are provided along the fluorescent lamp 14, and the fluorescent lamp 14 is spaced from both sides in the longitudinal direction. It is arranged so as to be sandwiched via. The light guides 21, 21 between the fluorescent lamps 14, 14 are formed separately. Then, each light guide 21 guides the irradiation light of the fluorescent lamp 14 facing each other.

Further, on the front side of the irradiation opening 13, a plate-shaped light diffusion / transmission member 22 as a diffuser for diffusing the irradiation light from the back is overlaid. Further, on the back side of the light diffusion / transmission member 22, the density of a portion facing the fluorescent lamp 14 and directly above the fluorescent lamp 14 is the highest, and the density is reduced as the distance from the fluorescent lamp 14 is reduced. Is provided, and a lamp image is less likely to be generated from the front surface of the light diffusion / transmission member 22.

On the front surface of the light diffusing and transmitting member 22, a liquid crystal display body 24 for displaying with liquid crystal is provided.

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

First, when the fluorescent lamp 14 is turned on, the light guide
21 is irradiated with light, and the light guide 21 guides the irradiation light from the fluorescent lamp 14, and the light guide 21 itself becomes bright, and the light is directed toward the irradiation opening 13. Further, the dot pattern 23 on the back surface of the light diffusion / transmission member 22 minimizes the irradiation light from the fluorescent lamp 14 directly above the fluorescent lamp 14, and reduces the decrease of the irradiation light as the distance from the fluorescent lamp 14 increases. It is formed on the light diffusion / transmission member 22 which is the light emitting surface of the above, and nonuniformity of light does not occur on the light diffusion / transmission member 22.

For this reason, the liquid crystal display 24 is also illuminated from the back side by the uniform irradiation light, and is also illuminated by the light guide 21 in a planar manner. Absent.

In each of the above embodiments, the straight tube type fluorescent lamp 14 is used for explanation. However, 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 sealed end portion which is stopped is inclined with respect to the central axis of the straight tube type glass bulb may be used.
The same effect can be obtained.

The positional relationship between the fluorescent lamp 14 and the light guide 21 is not limited to that shown in FIG. 1, but a plurality of fluorescent lamps are sandwiched between the light guides, the fluorescent lamp and the light guide. It is also possible to arrange them alternately.

[0026]

According to the illuminating device of the first aspect, since the light guide body for sandwiching the light source is arranged in the substrate so as to face the irradiation opening, the efficiency of the irradiation light from the light source is improved, In addition, it is possible to prevent uneven brightness from occurring on the irradiation surface.

According to the illuminating device of claim 2, in the illuminating device of claim 1, since the irradiation opening is optically closed by the diffuser to diffuse the irradiation light, the brightness generated on the irradiation surface can be controlled. Non-uniformity can be further prevented.

According to the lighting device of the third aspect, since the back surface of the diffuser has a dot pattern for light control, which has a high density on the light source and a lower density as the distance from the light source increases,
The lamp image can be made smaller.

According to the liquid crystal display device of the fourth aspect, since the liquid crystal display body is disposed on the front side of the illuminating device according to any of the first to third aspects, it is possible to prevent unevenness in brightness on 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 Light Diffusing Transmission Member as Diffuser 23 Dot Pattern 24 Liquid Crystal Display

Claims (4)

[Claims] 1. A base body having an irradiation opening formed therein, a light source disposed in the base, and a light guide body provided in the base body so as to face the irradiation opening and sandwiching the light source. An illuminating device comprising: 2. The illumination device according to claim 1, further comprising a diffuser that optically blocks an irradiation opening to diffuse irradiation light. 3. The lighting device according to claim 2, wherein a dot pattern for light control is provided on the back surface of the diffuser, the dot pattern having a high density on the light source and a low density with increasing distance from the light source. 4. A liquid crystal display device, characterized in that a liquid crystal display is provided on the front side of the lighting device according to any one of claims 1 to 3.