JPH11258601A - Illuminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain space saving and electric power saving by using a short lamp and also to reduce dark parts of light guide to improve an incident light efficiency by providing tapered parts tapering to the lamp sides, on light guide sides of lamp holders holding a lamp. SOLUTION: Lamp holders 11 holding a lamp 1 on both sides are provided with tapered parts 11a tapering to the lamp sides on the light guide sides. Namely, the tapered parts 11a are formed by diagonally tapering off a part of the lamp holders 11. Thus, dark parts in the light guide are reduced to obtain uniform illumination. Although light in the sideward directions is illuminated to the lamp holders and is absorbed or reflected by the lamp holders to travel in the directions different from the light guides in a conventional manner, this can effectively be utilized. Moreover, this arrangement makes it possible to improve an incident light efficiency and also limit the outside dimensions of the device within those of the light guides and results in space and electric power savings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device used for a backlight of a liquid crystal display device, and more particularly to an illuminating device having an improved efficiency of entering a light guide.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view showing a basic structure of a lighting device used for a backlight of a liquid crystal display device. In FIG. 1, reference numeral 1 denotes a straight tube type lamp as a light source unit, 2 denotes a lamp holder for holding the lamp 1 from both sides, 3 denotes a reflector for reflecting light from the lamp 1, and 4 denotes light from the lamp 1 and a reflector. The light reflected by 3 is a flat light guide from the side end surface, and has a reflecting plate 5 on one surface (back surface) and a diffusing plate 6 on the other surface (front surface).

In the above configuration, light from the lamp 1 enters the light guide 4 directly or via the reflector 3, and is diffused and reflected by a pattern printed on the bottom surface of the light guide 4 on the side of the reflection plate 5, so that the light guide 4 Make the whole light up uniformly. Then, uniform surface light emission can be obtained from the illuminated surface of the diffusion plate 6 on the surface of the light guide 4.

FIG. 5 is a diagram showing how light travels from the lamp 1 to the light guide 4 by arrows in the illumination device having the above-described configuration. FIG. 6 shows how light travels when the lamp holder is arranged outside the light guide.

[0005]

However, in the above-mentioned conventional illuminating device, as shown in FIG. 5, for example, points A, B, and C are all provided with light from the lamp. Brightness is large because it is incident from the direction,
In the vicinity of the points X and Y, only light from a specific angle from the lamp bordering on the Z direction is incident, so that the amount of light is smaller than that of the points A, B, and C, resulting in a dark portion, and the quality is reduced. There was a problem.

Therefore, it has been proposed to dispose the lamp holder outside the light guide as shown in FIG. 6 to increase the amount of incident light near the X and Y points to eliminate the dark part. There has been a problem that the external dimensions of the device have been increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is possible to save space and power by using a short lamp, and at the same time, to reduce the dark portion of the light guide. It is an object of the present invention to provide a lighting device with improved light incident efficiency.

[0008]

The lighting device according to the present invention is configured as follows.

(1) In a lighting device in which light from a lamp is incident on a light guide and emits surface light, a taper portion is provided on the light guide side of a lamp holder for holding the lamp so that the lamp side becomes lower.

(2) In a lighting device in which light from a lamp is incident on a light guide and emits surface light, a step portion with a lower lamp side is provided on a light guide side of a lamp holder for holding the lamp.

[0011]

FIG. 1 is a perspective view showing the structure of one embodiment of the present invention. In the figure, reference numeral 1 denotes a straight tube lamp, and 11 denotes a lamp holder for holding the lamp 1 from both sides, and a light guide (not shown) is provided with a tapered portion 11a having a lower lamp side.

The other structure of the lighting device is the same as that shown in FIG.

In this embodiment, as shown in FIG. 1, a part of the lamp holder 11 is cut obliquely to form a tapered portion 11a, so that light traveling in the Z direction as shown in FIG. 2 can also be used. Thus, a dark portion in the light guide can be reduced, and uniform light emission can be obtained.

That is, as shown in FIG. 5, the light in the Z direction hits the lamp holder and is absorbed or reflected by the lamp holder and travels in a direction different from that of the light guide. Is provided with a tapered portion 11a, so that light in the Z direction can also be used effectively. In addition, by adopting such a structure, the dark portion near the end of the lamp is reduced and the light entrance efficiency is improved, and at the same time, the external dimensions of the apparatus are reduced to the external dimensions of the light guide using the short lamp 1. Thus, space saving and power saving can be achieved.

FIG. 3 is a perspective view showing another embodiment of the present invention, and shows only a lamp holder portion. In the lamp holder 12 of the present embodiment, steps 12a and 12b having a lower lamp side are provided on the light guide side. FIG. 3 (a)
3 shows an example in which a stepped portion 12a reduced to the tube diameter of the lamp 1 is formed, and FIG. 3B shows an example in which a stepped portion 12b lower than that is formed.

As described above, even if the angle is used instead of the taper, the same operation and effect as the embodiment of FIG. 1 can be obtained, and the dark portion of the light guide can be reduced, and at the same time, space and power can be saved. Can be planned.

[0017]

As described above, according to the present invention, space saving and power saving can be achieved by using a short lamp, and at the same time, the dark portion of the ride guide is reduced and the light entrance efficiency of light is reduced. There is an effect that is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing how light travels in one embodiment.

FIG. 3 is a perspective view showing the configuration of another embodiment of the present invention.

FIG. 4 is a perspective view showing a basic configuration of a lighting device.

FIG. 5 is an explanatory view showing how light travels in a conventional example.

FIG. 6 is an explanatory diagram showing how light travels in another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lamp 3 Reflector 4 Light guide 5 Reflector 6 Diffusion plate 11 Lamp holder 11a Taper part 12 Lamp holder 12a Step part 12b Step part

Claims (2)

[Claims] 1. An illumination device for emitting light from a lamp to a light guide to emit light by surface illumination, wherein a lamp holder for holding the lamp is provided with a tapered portion on the light guide side where the lamp side is lowered. apparatus. 2. An illumination device for emitting light from a lamp to a light guide and emitting light by surface illumination, wherein a step portion with a lower lamp side is provided on a light guide side of a lamp holder for holding the lamp. .