JPH0553111A - Light guiding plate structure of thin edge light type liquid crystal display device - Google Patents

Abstract

PURPOSE:To efficiently utilize light from a fluorescent lamp even if a difference between the diameter of a light guiding plate and the tube diameter of the fluorescent lamp by for forming a light leading-in part for total--reflecting substantially light from a light source in the end part of the light guiding plate. CONSTITUTION:A fluorescent lamp 1 is fixed to the end part, of a light guiding plate 3 consisting of an acryl resin and glass, etc., by a reflecting film 2 in which an adhesive agent is applied in its inside surface. In the end part to which the fluorescent lamp 1 is fixed, of the light guiding plate 3, a light leading-in part 31 is formed. The fluorescent lamp 1 side of this light leading part 31 has the diameter of thickness being roughly equal to the tube diameter of the fluorescent lamp 1. An inclination angle thetaof the light leadingin pad 31 is set so that light from the fluorescent lamp 1 is subjected to total reflection and led into the light guiding plate 3. Accordingly, even if there is a large difference between the diameter of the light guiding plate 3 and the tube diameter of the fluorescent lamp 1, light from the fluorescent lamp 1 is almost all led into the light guiding plate 3, therefore, the efficiency of light is not spoiled, and energy efficiency of the edge type liquid crystal, display device can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate structure for a thin edge light type liquid crystal display device. More specifically, the present invention relates to a light guide plate structure of a thin edge light type liquid crystal display device capable of efficiently guiding light from a light source to the light guide plate.

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal display device, a thin light guide plate in which a round fluorescent lamp is arranged at an end of the light guide plate as shown in FIG. 3 is used. In the figure, 101 is a fluorescent lamp, 102 is a reflection film, 103 is a light guide plate, 104 is a reflection plate, and 105 is a diffusion plate.

However, due to the recent demand for thinner and lighter liquid crystal display devices, the thickness of the light guide plate 103 tends to be thin. At present, a plate having a thickness of 2.2 mm has been put into practical use, and in the future. Is expected to be even thinner.

On the other hand, the fluorescent lamp 101 having a tube diameter of 4.1 mm has only been put into practical use due to technical restrictions.

Therefore, the fluorescent lamp 101 is attached to the reflecting film 102.
In the conventional edge light type liquid crystal display device fixed to the end of the light guide plate by using, the thickness of the light guide plate 103 and the fluorescent lamp 101
There is a problem that the light from the fluorescent lamp 101 is not effectively used because the difference from the tube diameter of No. 1 becomes too large.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art. Even if there is a large difference between the thickness of the light guide plate and the tube diameter of the fluorescent lamp, the light from the fluorescent lamp will not be emitted. An object of the present invention is to provide a light guide plate used for a thin edge-light type liquid crystal display device that can be effectively used.

[0007]

SUMMARY OF THE INVENTION The present invention is a light guide plate structure for a thin edge-light type liquid crystal display device which utilizes a light source having a light emitting portion larger than the thickness of the light guide plate. The present invention relates to a light guide plate structure of a thin edge light type liquid crystal display device, characterized in that a light introducing portion for totally reflecting the light is formed at an end portion of the light guide plate.

[0008]

In the present invention, since the light introducing portion for substantially totally reflecting the light from the light source is formed at the end portion of the light guide plate, almost all the light from the light source can be guided to the light guide plate.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

FIG. 1 is a schematic view of a liquid crystal display device using a light guide plate according to one embodiment of the present invention, and FIG. 2 is a schematic view of another embodiment of the present invention. In the figure, 1 is a fluorescent lamp, 2 is a reflective film, and 3 is
Is a light guide plate, 4 is a reflection plate, 5 is a diffusion plate, 6 is a liquid crystal display panel driving device, and 7 is a liquid crystal display panel.

The fluorescent lamp 1 is the same as that conventionally used in an edge light type liquid crystal display device, and its tube diameter is 4.1 mm. The fluorescent lamp 1 is fixed to the end portion of the light guide plate 3 made of acrylic resin or glass by a reflective film 2 having an adhesive applied to the inner surface thereof, as in the conventional edge light type liquid crystal display device. A light introducing portion 31 is formed at the end of the light guide plate 3 to which the fluorescent lamp 1 is fixed. The fluorescent lamp 1 side of the light introducing portion 31 has a plate thickness substantially equal to the tube diameter of the fluorescent lamp 1. The inclination angle θ of the light introducing section 31 is set so that the light from the fluorescent lamp 1 is totally reflected and introduced into the light guide plate 3. Specifically, it is appropriately determined in consideration of the wavelength of light from the fluorescent lamp 1 used, the refractive index of the light guide plate 3, and the like. To give a specific example, if the material of the light guide plate is, for example, light crown glass, the critical angle of total reflection is 40 degrees. All the emitted parallel light is guided into the light guide plate 3.

In the embodiment shown in FIG. 1, the inclined surface of the light introducing portion 31 is formed in a linear shape. However, the inclined surface does not necessarily have to be formed in a linear shape. It may be curved or polygonal to guide. However, it is preferable to have a linear shape from the viewpoint of ease of processing.

As the light guide plate 3, in addition to the above-mentioned acrylic resin and glass, a transparent case enclosing a fluid having a large critical angle of total reflection can be used. It is preferable to use a general material in terms of cost and the like.

The reflection plate 4, the diffusion plate 5, the liquid crystal display panel driving device 6, and the liquid crystal display panel 7 are the same as those conventionally used in the edge light type liquid crystal display device.
Detailed description thereof will be omitted.

In the liquid crystal display using the light guide plate 3 having the light introducing portion 31 constructed as described above, almost all the light from the fluorescent lamp 1 is introduced into the light guide plate 3, so that the conventional edge light type is used. Does not impair the efficiency of light like things. Therefore, a brighter screen than the conventional one can be obtained with the same power consumption. Further, if the same brightness is required, the tube diameter of the fluorescent lamp used can be reduced.

In FIG. 2, the inclined surface of the light introducing portion 31 is provided on the light guide plate 3.
An example formed on both sides of is shown.

Whether the inclined surface of the light introducing section 31 is only one side or both sides of the light guide plate 3 is appropriately selected according to the purpose of use of the liquid crystal display device to which the light guide plate 3 is applied. There is no particular limitation.

Further, in the present embodiment, the illuminating device is a fluorescent lamp, but the illuminating device is not limited thereto, and any device can be used as long as it can provide a liquid crystal display panel with a predetermined brightness. it can. Specific examples thereof include an LED lamp, an incandescent bulb, and an EL.

[0019]

As described above, according to the present invention, the light from the lighting device can be effectively guided to the light guide plate, and the energy efficiency of the edge light type liquid crystal display device can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view of a liquid crystal display device to which a light guide plate according to an embodiment of the present invention is applied.

FIG. 2 is a schematic view of a liquid crystal display device to which a light guide plate according to another embodiment of the present invention is applied.

FIG. 3 is a schematic view of a light guide plate of a conventional edge light type liquid crystal display device.

[Explanation of symbols]

 1 Fluorescent Lamp 2 Reflecting Film 3 Light Guide Plate 4 Reflecting Plate 5 Diffusing Plate 6 Liquid Crystal Display Panel Driving Device 7 Liquid Crystal Display Panel

Claims (1)

[Claims] 1. A light guide plate structure for a thin edge-light type liquid crystal display device, which utilizes a light source having a light emitting portion larger than the thickness of the light guide plate, wherein the light introducing portion is configured to substantially totally reflect the light from the light source. A light guide plate structure of a thin edge-light type liquid crystal display device, characterized in that the light guide plate is formed at an end portion of the light guide plate.