JP2521824B2 - Lighting equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a transmissive illumination device that illuminates by irradiating light from behind.

[Prior Art] A conventionally known transmissive illumination device has a configuration as shown in FIG. 5 and includes a light source 1, a reflection plate 2 and a diffusion plate 3, and direct light of the light source 1 and the reflection plate 2 are provided. The diffused light is reflected by the diffusing plate 3 to form diffused light, and then the image display plate 5 is illuminated from behind.

[Problems to be Solved by the Invention] Although such an illuminating device illuminates the image display plate 5 by the diffusing action of the diffusing plate so that there is relatively no unevenness in brightness, it provides a sufficiently uniform brightness distribution. However, there is a problem in that the brightness from the light source cannot be effectively used, and the brightness from the light source is partially reduced.

According to the present invention, the light behind the light source, that is, the light toward the reflector side of the light source, which does not contribute to the illumination in the conventional example, is directed to the diffuser plate without waste, and the brightness of the relatively low brightness part on the diffuser plate is increased. Thus, it is an object of the present invention to provide an illuminating device which enhances the light use efficiency and performs bright illumination having a uniform luminance distribution.

[Means for Solving the Problems] An illumination device of the present invention includes a point light source such as an incandescent lamp or an edge light source such as a cold cathode tube, a reflecting plate, and a diffusing plate, and an incident end face in the vicinity of the light source. The light guide is placed so that it is located below the center line of the light source. Of the light from the light source, the light that goes to the lower part of the light source is transmitted through the light guide body and is emitted from the surface of the light guide plate. Of the comparatively low brightness, the image display plate is illuminated from the back surface thereof with bright light having a uniform brightness distribution.

Example Next, an example of the lighting device of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of an embodiment of the present invention, in which 1 is a line light source such as a cold cathode tube, 2 is a reflecting plate, 3 is a diffusing plate, and these are substantially the same as the conventional example shown in FIG. Is. Reference numeral 4 denotes a light guide body made of a transparent material such as glass or acrylic resin, the light incident surface 4a of which is arranged close to the light source 1.
It is located on the left and right of. Further, in this embodiment, a mask is provided above the light source 1 so that the brightness on the diffusion plate 3 becomes uniform.
1a is provided to partially control the direct light from the portion near the diffuser plate 3 where the brightness becomes too high. Also, the light guide has an incident end 4a.
Is wide and has a triangular cross section or a curved shape that becomes narrower toward the front.

In this embodiment, the diffusion plate 3 of the light from the light source 1
The mask 1a is provided in the portion closest to the light source 1 to control the amount of light, and the light which is emitted from the lower part of the light source 1 and was wasted in the past is guided to the inside of the light guide 4 through the incident end face 4a.
By sequentially injecting light from 4b, it is possible to hit the diffuser plate 3 to increase the brightness on the diffuser plate and, as shown in FIG. 4, a comparatively low brightness part A as shown by the conventional curve b.
Is also made bright so that the luminance is substantially uniform in all parts as indicated by the curve a.

This light guide 4 has a height L of the incident end face 4a as shown in FIG.
Is preferably lower than the height h to the center line XX ′ of the light source 1, and for example, the diameter of L is preferably 3 mm or less with respect to the tube diameter of the light source 1 of 6 mm. Also, the back surface 4 of the light guide 4
It is more preferable that the and are made to have a satin finish or a pattern by printing is provided to have a diffusing effect.

FIG. 3 is an example of an illuminating device using two light sources 1 in another embodiment. Also in this embodiment, the light guides 4 are provided on the left and right of the light source, respectively.
Is provided to achieve the same effect as that of the embodiment shown in FIG.

[Effects of the Invention] The lighting device of the present invention is a lighting device in which the light on the back surface of the light source is effectively used by the arrangement of the light guides, and the brightness on the diffuser plate is substantially uniform and bright by this light. is there.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a diagram showing the arrangement of a light source and a light guide body of the above embodiment, and FIG. 3 is a sectional view of another embodiment of the present invention. FIG. 4 is a diagram showing the luminance distribution on the diffuser plate of the present invention and the conventional lighting device, and FIG. 5 is a sectional view of the conventional lighting device. 1 ... Light source, 2 ... Reflector, 3 ... Diffuser 4 ... Light guide

Claims (1)

(57) [Claims] 1. An illumination device comprising a light source, a reflector, and a diffuser plate arranged on the side opposite to the reflector with respect to the light source, wherein the light source of the light source is substantially aligned with the reflector. A transparent light guide extending from the lateral side toward the end direction of the diffusion plate is arranged, and the incident end face of the light guide is near the lateral side of the light source and closer to the reflection plate side than the center of the light source. The illuminating device is characterized in that it is located and the surface of the light guide extends in the end direction of the diffuser plate in a state of being inclined with respect to the diffuser plate from the lateral vicinity of the light source.