JPH05281540A - Lighting system and liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device preventing the nonuniformity of brightness generated on the irradiation face. CONSTITUTION:When fluorescent lamps 14 are lit up, prism bodies 21 are irradiated by light. In the prism bodies 21, the index of light refraction is larger toward a base body 11, and the irradiation light from each fluoresent lamp 14 is refracted in such a way as to irradiate a light diffuse transmission member 23 uniformly up to the middle part between the fluorescent lamps 14, 14. Efficient irradiation can be obtained because of the short optical path distance to irradiate the center of an irradiation opening part 13. The apparent luminescence face is formed on the light diffuse transmission member 23, and it is hard to generate the nonuniformity of light on this light diffuse transmission member 23. A liquid crystal display body 24 is also irradiated by uniform irradiation light from the back face, so that brightness can be made uniform.

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.

Therefore, there is known a structure in which a lens is arranged in front of a light source as described in, for example, Japanese Patent Application Laid-Open No. 2-52314.

[0006]

However, in the case of the structure described in Japanese Patent Application Laid-Open No. 2-52314, the irradiation light from the lens can uniformly collect and diffuse the irradiation opening from the light source in the irradiation opening. Therefore, there is a problem that 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 an irradiation opening side of the light source. And a prism body which irradiates the irradiation light from the light source substantially uniformly over the entire surface of the irradiation opening.

According to a second aspect of the present invention, in the illuminating device according to the first aspect, two light sources are provided so as to face each other, and the light refraction index of the prism body increases toward the substrate side. ..

An illumination device according to a third aspect is the illumination device according to the first or second aspect, which is provided with a diffuser that optically closes the irradiation opening and diffuses the irradiation light.

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 present invention, the prism body irradiates the irradiation light from the light source substantially uniformly over the entire surface of the irradiation opening, so that the unevenness of the brightness generated on the irradiation surface is prevented.

A lighting device according to a second aspect of the present invention is the lighting device according to the first aspect, wherein the two light sources facing each other illuminate the light source up to the center between the light sources, thereby preventing uneven brightness on the illuminated surface. At the same time, since the light refractive index of the prism body is increased toward the substrate side, the optical path distance is reduced and the efficiency is improved.

According to a third aspect of the present invention, in the illumination apparatus according to the first or second aspect, since the irradiation light from the prism body is diffused by the diffuser, it is possible to prevent unevenness in brightness on the irradiation surface. ..

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]

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 is 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, a prism body 21 orthogonal to the reflecting surface 15 is attached to the front side of the fluorescent lamp 14. And
The prism array 22 of the prism body 21 is parallel to the fluorescent lamp 14. Further, the prism body 21 has a larger light refractive index toward the base body 11 side, and uniformly irradiates the irradiation light from the fluorescent lamp 14 to the center of the irradiation opening 13.

Further, a plate-like light diffusion / transmission member 23 as a diffuser for diffusing the irradiation light from the prism body 21 is superposed so as to optically close the irradiation opening 13.

On the front surface of the light diffusing and transmitting member 23, a liquid crystal display 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 prism body 21 is irradiated with light. In the prism body 21, fluorescent light is uniformly irradiated to the middle of the fluorescent lamps 14 and 14, respectively. The light emitted from the lamp 14 is refracted. That is, as shown in FIG. 1, the light radiated to the upper part of the prism body 21 illuminates almost the central part of the light diffusion and transmission member 23, and the light radiated to the lower part of the prism body 21 is the light diffusion and transmission member. 23 is irradiated near the prism body 21 for refracting the irradiation light, and the light irradiated to the intermediate portion of the prism body 21 is in the vicinity of the central portion of the light diffusion and transmission member 23 and the vicinity of the prism body 21 for refracting the irradiation light. Irradiate the middle. Then, an apparent light emitting surface is formed on the light diffusion / transmission member 23, and unevenness of light is unlikely to occur on the light diffusion / transmission member 23.

For this reason, the liquid crystal display 24 is also illuminated from the back side by the uniform irradiation light, and is therefore illuminated from the back surface by the uniform irradiation light.

Further, since the prism body 21 has a larger light refractive index toward the base 11 side and, conversely, has a smaller light refractive index toward the light diffusion / transmission member 23, it is assumed that the prism body 21 is refracted from the base 11 side. Since the distance l ₂ due to actual refraction can be made shorter than the distance l ₁ , the optical path distance at the center of the irradiation opening 13 can be shortened and efficiency can be improved.

In the above embodiment, 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. The same effect can be obtained by using a fluorescent lamp or the like in which the central axis of the sealed end portion is inclined with respect to the central axis of the straight tube type glass bulb.

[0026]

According to the illuminating device of the first aspect of the present invention, the irradiation light from the light source is applied to the irradiation opening by the prism body almost uniformly over the entire surface. To prevent.

According to the lighting device of the second aspect, in addition to the lighting device of the first aspect, two light sources facing each other are provided.
Irradiation up to the center between the light sources prevents uneven brightness on the illuminated surface, and increases the prism's optical refractive index toward the substrate side, thus reducing the optical path distance and improving efficiency. To do.

According to the lighting device of the third aspect, in addition to the lighting device of the first or second aspect, since the irradiation light from the prism body is diffused by the diffuser, the unevenness of the brightness generated on the irradiation surface is prevented. More preventable.

According to the liquid crystal display device of the fourth aspect, since the liquid crystal display body is arranged on the front side of the illuminating device according to any of the first to third aspects, the liquid crystal display body does not have uneven brightness. ..

[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 Prism 23 Light Diffusing and Transmissive Member as Diffuser 24 Liquid Crystal Display

Claims (4)

[Claims] 1. A substrate having an irradiation opening formed therein, a light source disposed in the substrate, and an irradiation opening of the light source, the irradiation light being emitted from the light source. An illuminating device comprising: a prism body that irradiates the entire surface with substantially uniform irradiation. 2. The two light sources are provided so as to face each other, the prism body is provided for each of these light sources, and the optical refractive index of the prism body increases toward the substrate side. Lighting equipment. 3. The illumination device according to claim 1, further comprising a diffuser that optically blocks the irradiation opening and diffuses the irradiation light. 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.