JPH07270618A - Lighting device and liquid crystal display device including the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent or reduce the deterioration of the light guide plate due to heating over time, while increasing the brightness. [Structure] Fluorescent lamps 14a, 1 are provided on the side of the end surface of the light guide plate 13.
4b are arranged facing each other. A reflector 18 having a plurality of reflection chambers 18d whose inner surface is formed as a reflection surface 18b is interposed between the light guide plate 13 and the fluorescent lamps 14a and 14b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device in which a rod-shaped light source is arranged opposite to an end surface of a light guide plate made of acrylic resin or the like, and a liquid crystal display device including the illuminating device. The present invention relates to a liquid crystal display device including this.

[0002]

2. Description of the Related Art Conventionally, an example of this type of illumination device is shown in FIG. This illuminating device 1 is called a side (edge) light type, and substantially the entire inner surface 2a of the lamp case 2 is formed as a reflecting surface, and a reflecting sheet 2b is attached on the inner bottom surface thereof.

Inside the lamp case 2, a rectangular plate-shaped light guide plate 3 made of acrylic resin, for example, and a pair of right and left straight fluorescent lamps 4a and 4b, which are arranged opposite to each other at the left and right ends thereof, respectively. Are accommodated and the light emitting surface of the light guide plate 3 is made to emit light in a planar shape. Further, on the light emitting surface of the light guide plate 3, the diffusion plate 5 and the liquid crystal display panel 6 are sequentially overlapped in this order, and the liquid crystal display panel 6 is illuminated from the back side.

Another conventional lighting device 7 of this type shown in FIG. 6 is described in Japanese Utility Model Publication No. 62-74282, which is made of an acrylic resin facing a straight tube fluorescent lamp 8. A plurality of concavities and convexities 10 are formed on the end surface of the light guide plate 9 and the like, and the concavities and convexities 10 diffusely reflect the incident light from the fluorescent lamp 8 as shown by solid line arrows in the figure to improve the brightness uniformity.

[0005]

However, in such conventional lighting devices 1 and 7, since the fluorescent lamps 4a, 4b and 8 which are heat sources are close to the light guide plates 3 and 9,
There is a problem that the light guide plates 3 and 9 made of acrylic resin are heated by the heat generated from the fluorescent lamps 4a, 4b and 8 and deteriorate with time. Further, in the conventional illumination device 7 shown in FIG. 6, as shown by the broken line arrow in the figure, part of the light diffusely reflected by the end surface of the unevenness 10 of the light guide plate 9 is not incident on the light guide plate 9 but is reflected to the outside. However, there is a problem that the brightness of the light guide plate 9 is reduced.

Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to prevent or reduce deterioration of the light guide plate due to heating over time, and to improve the brightness and a lighting device. It is to provide a liquid crystal display device including the same.

[0007]

The present invention is configured as follows in order to solve the above-mentioned problems.

According to a first aspect of the present invention, in an illuminating device having a light guide plate and a rod-shaped light source arranged so as to face an end face of the light guide plate, the light from the rod-shaped light source is diffused and then reflected. It is characterized in that a reflector having a plurality of reflection chambers for guiding light to the light plate is interposed between the light guide plate and the linear light source.

According to a second aspect of the present invention, the reflector is a cylindrical reflector body having an inner surface formed as a reflecting surface.
It is characterized in that a plurality of reflecting chambers are formed by dividing the reflecting plate into a lattice shape.

Further, the invention according to claim 3 of the present application is
The reflector is characterized in that the central axis thereof is arranged in parallel with the central axis of the rod-shaped light source in the same plane.

Furthermore, the invention according to claim 4 of the present application is characterized in that the illuminating device according to any one of claims 1 to 3 is configured to illuminate the back surface of the liquid crystal display panel. To do.

[0012]

When the light from the rod-shaped light source passes through the plurality of reflection chambers of the reflector, it is diffusely reflected by the reflecting surfaces of the inner surfaces thereof and then enters the light guide plate from its end face. Therefore, the brightness of the light guide plate can be improved.

Further, since the reflector is interposed between the rod-shaped light source which is a heat source and the light guide plate, the heat from the rod-shaped light source can be shielded by the reflector. Therefore, deterioration with time due to heating of the light guide plate can be prevented or reduced.

[0014]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a partial vertical cross-sectional view showing an embodiment in which the lighting device according to the present invention is applied to a liquid crystal display device. The liquid crystal display device 11 has a lamp case 12 made of acrylic resin or the like. Rectangular light guide plate 13 and this light guide plate 13
In the figure, a pair of left and right fluorescent lamps 14a and 14b, for example, in the shape of straight tubes, which are arranged to face each other at the left and right ends, are incorporated.

The lamp case 12 has a reflecting surface 12a formed on almost the entire inner surface thereof, and an opening 12b formed on the upper surface in the figure. On the outer bottom surface of the light guide plate 13, a reflective coating 15 such as white coating is applied to form a reflective film 15 substantially continuously over the entire surface.

A diffusing plate 16 is placed on the light exit surface of the upper surface of the light guide plate 13 in the figure to constitute an illuminating device.
6, the liquid crystal display panel 17 is overlaid, and the left and right edges of the liquid crystal display panel 17 in the drawing are provided with the opening 12
It is held by the left and right end portions 12c and 12d of b. The lighting circuits for the pair of fluorescent lamps 14a and 14b and the drive circuit for the liquid crystal display panel 17 are not shown.

2 and 3 between the left and right ends of the light guide plate 13 and the pair of left and right fluorescent lamps 14a and 14b.
The elongated rectangular tube-shaped reflectors 18 shown in FIG.

The main body 18a of the reflector 18 is formed of aluminum or the like into an elongated rectangular tube shape. The reflector main body 18a has a length substantially equal to the length of the fluorescent lamps 14a and 14b, and the fluorescent lamps 14a and 14b and the light guide plate 13 are provided.
The left and right side surfaces in the figure, which respectively face the end surfaces of the, are opened over the entire length, and a reflective material such as silver is deposited on the entire inner surface by vapor deposition or the like to form the reflective surface.

Further, the reflector 18 has a main body 18a in which a horizontal plate 18b having an outer surface formed as a reflection surface is divided into a plurality of vertical plates 18c into a lattice shape and divided into a plurality of small-angle tubular shapes. Each of the reflection chambers 18d is formed.

As shown in FIG. 4, each reflector 18 is arranged in the lamp case 12 so that its central axis is substantially parallel to the central axis of each fluorescent lamp 14a, 14b, and each fluorescent lamp is arranged. Light emitted from 14a and 14b is diffusely reflected through each small reflection chamber 18d and is incident on the end surface of the light guide plate 13.

Therefore, each fluorescent lamp 14a, 14b
When passing through the inside of each small reflection chamber 18d of each reflector 18, the light is diffusely reflected by the inner surface of the reflection and then enters the light guide plate 13, and the substantially inner surface of the lamp case 12 is formed as a reflection surface. Therefore, the incident light on the light guide plate 13 is increased to improve the brightness, and the light diffusion effect is improved, so that the brightness uniformity can be increased.

Further, since the heat from each fluorescent lamp 14a, 14b can be shielded by each reflector 18, deterioration with time due to heating of the light guide plate 13 can be prevented or reduced.

The liquid crystal display panel 17 may be replaced with, for example, a transparent signboard or a guide plate to form a thin signboard light or a guide light such as an evacuation guide light.

[0025]

As described above, according to the present invention, the light from the rod-shaped light source is diffusely reflected by the reflecting surfaces of the plurality of reflecting chamber inner surfaces of the reflector, and then is made incident on the light guide plate.
The brightness can be improved.

Further, since the reflector is interposed between the rod-shaped light source which is a heat source and the light guide plate, the heat from the rod-shaped light source can be shielded by the reflector. Therefore, deterioration with time due to heating of the light guide plate can be prevented or reduced.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view of essential parts of the embodiment shown in FIG.

3 is a perspective view of the reflector shown in FIG. 1. FIG.

FIG. 4 is a front view showing the positional relationship between the reflector shown in FIG. 1 and a fluorescent lamp.

FIG. 5 is a vertical sectional view showing a part of a conventional liquid crystal display device.

FIG. 6 is a plan view of a part of another conventional lighting device.

[Explanation of symbols]

 11 Liquid Crystal Display Device 12 Lamp Case 12a Reflective Inner Surface 13 Light Guide Plate 14a, 14b Fluorescent Lamp 15 Reflective Surface 16 Diffuser 17 Liquid Crystal Display Panel 18 Reflector 18a Reflector Main Body 18b Horizontal Plate 18c Vertical Plate 18d Small Reflection Chamber

Claims (4)

[Claims] 1. A lighting device having a light guide plate and a rod-shaped light source arranged to face an end face of the light guide plate, wherein a plurality of reflection chambers diffusely reflect the light from the rod-shaped light source and then guide the light to the light guide plate. An illuminating device, characterized in that a reflector having the above is interposed between the light guide plate and the linear light source. 2. The reflector is characterized in that a plurality of reflecting chambers are formed by partitioning a tubular reflector body having an inner surface formed into a reflecting surface into a grid shape by a reflecting plate. Lighting equipment. 3. The illuminating device according to claim 1, wherein the reflector is arranged so that its central axis is flush with the central axis of the rod-shaped light source in the same plane. 4. A liquid crystal display device, wherein the lighting device according to claim 1 is configured to illuminate the back surface of the liquid crystal display panel.