JPH11176225A - Illumination unit and liquid crystal display device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve power consumption by lessening the leak current to a reflector which has been a problem for establishment of a high brightness and large screen construction. SOLUTION: An illumination unit is structured so that a light guide plate 1 to regulate and make uniform the light is provided on the side face of a fluorescent lamp 8 for illumination, and the lamp 8 is held certainly by a reflector 7 to make uniform the spatial distance between the two members, and thereby flow of leak current is prevented from the lamp 8 to the reflector and also the lamp is protected against external shock by the reflector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination unit used for illumination of a transmission type display device and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art Conventionally, in a display device for information equipment such as a laptop or notebook type word processor or a personal computer, an image is formed on a transmission type liquid crystal panel by utilizing features such as light weight, thinness and low power consumption. Are frequently used.

[0003] In recent years, along with the colorization of such a liquid crystal display device, a device having a built-in illumination unit for illuminating a display area of a liquid crystal panel from the back surface has become the majority. Most of these lighting units are edge light types using a light guide plate with the spread of notebook-type word processors and personal computers that emphasize portability these days.

FIG. 3 is a sectional view of a conventional edge light type illumination unit (on the side where fluorescent lamps are arranged). In this edge light type illumination unit, in order to effectively use the divergent light from the fluorescent lamp, a reflection plate (or a reflection sheet) having the same shape as the outer shape of the light guide plate 31 is provided on the back surface of the light guide plate 31 that has been equalized. ) 32, a resin film sheet 34 is provided on the surface of the light guide plate 31, and a fluorescent lamp 37 disposed on the side surface of the light guide plate is wrapped by a reflector 36. The reflector is formed of a resin sheet such as PET. It consisted of a reflective sheet formed by depositing a highly reflective metal such as Ag. The above members are incorporated into a housing 33 which is an outer frame made of resin, and are held together with the back cover 35.

[0005]

However, with the recent spread of notebook type word processors and personal computers, demands for higher brightness and larger screens and the characteristics of liquid crystal display devices, such as thin and
Demands for lightweight and low power consumption have been increasing.

[0006] In order to realize a large screen, high brightness, thin, lightweight, and low power consumption, the thickness of the light guide plate is reduced, the fluorescent lamp is made thinner, and the fluorescent lamp lighting frequency is increased to increase the brightness. Has been responding.

[0007] However, in the conventional reflector composed of a reflection sheet made of a resin, when the lighting frequency is increased, the leakage current from the fluorescent lamp to the reflector increases, resulting in a large loss of power consumption. I was In addition, the reflector formed of a resin-made reflection sheet cannot reliably hold the fluorescent lamp, and it is difficult to mechanically protect the fluorescent lamp, and there is a risk that the fluorescent lamp may be damaged. Further, there is a problem that it is difficult to maintain a reflector having a desired shape with a reflector formed of a resin-made reflection sheet.

The present invention solves the above-mentioned conventional problems. When the fluorescent lamp is lit at a high frequency, the leakage current to the reflector is remarkably reduced to improve the power consumption and the holding power of the fluorescent lamp. It is an object of the present invention to provide a lighting unit having a reflector capable of keeping a strong image and a liquid crystal display device using the same.

[0009]

According to a first aspect of the present invention, there is provided a lighting unit for illuminating a liquid crystal panel from a back surface thereof. A light guide plate having light equalizing means for equalizing light incident on the light source, a fluorescent lamp disposed on at least one side of the light guide plate, and receiving light for the illumination, A reflector that reflects the divergent light from the fluorescent lamp toward the light guide plate, a reflector that covers the back surface of the light guide plate, a resin film sheet that covers the surface of the light guide plate, and a frame body on which these are mounted The reflector has a configuration in which a metal plate having a thickness of 2 mm or less is bonded to a resin sheet.

The liquid crystal display device according to the third aspect is the first aspect.
And 2 are provided, and a liquid crystal panel and a metal frame having a perforated display range of the liquid crystal panel are provided above the lighting unit.

According to the present invention, since the fluorescent lamp is securely held by the reflector, it has an effect of preventing a leakage current from the fluorescent lamp to the reflector, and the illumination unit is downsized and the liquid crystal display device is downsized. Becomes easier.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a lighting unit and a liquid crystal display device using the same according to an embodiment of the present invention will be specifically described with reference to FIGS.

(Embodiment) FIG. 1 is a sectional view showing a configuration of a lighting unit according to the present embodiment. FIG. 1 (a) shows a side where no fluorescent lamp is arranged, and FIG. The side where the fluorescent lamp is arranged is shown.

In this lighting unit, as shown in FIG. 1 (a), a dot pattern for light equalization is formed on the back side of the light guide plate 1, and on the surface of the light guide plate 1, 1, a reflection plate 2 designed to have an outer shape equivalent to that of the light guide plate 1 is placed, and a back cover 6 formed to be larger than the light guide plate 1 and the housing 3 are fixed by screws 4 so as to be attached.
In addition, a resin film sheet 5 made of a diffusion sheet, a prism sheet, or the like is disposed on the front surface side (outgoing light surface side) of the light guide plate 1.

As shown in FIG. 1B, a fluorescent lamp 8 is provided on a side surface of the light guide plate by a reflector 7.
The fluorescent lamp 8 is arranged so as to be covered except for the incident light side, and the upper part of the fluorescent lamp 8 is fixed by the back cover 6.

In the lighting unit according to the present embodiment, after the resin film sheet 5, the light guide plate 1, and the reflection plate 2 are sequentially inserted into the housing 3, the fluorescent lamp 8 is mounted together with the reflector 7, and the back cover 6 is mounted. Screw 4 on housing 3
It is fixed. The reflector and the reflector may be directly fixed to the housing with screws without using the back cover.

The reflector 7 used in the illumination unit of the present embodiment is a stainless steel plate having a white resin sheet (polyester or the like) adhered to one surface thereof, for example, a thickness of 2 mm or less. Plate or brass plate
It is also possible to use (brass).

In the drawings showing the configuration of the illumination unit in the present embodiment, the cross-sectional shape of the reflector 7 is a U-shape, but the reflector 7 may be formed in any shape such as a semicircle or an ellipse. In addition, although the case where the number of the fluorescent lamps 8 is one is shown, a plurality of fluorescent lamps or a lighting unit arranged on a plurality of sides is included.

FIG. 2 is a cross-sectional view of a liquid crystal display device using the illumination unit according to the present embodiment. FIG. Indicates the side where is arranged. This liquid crystal display device
The liquid crystal panel 9 is placed on the housing 3 as shown in FIG.
The lighting unit and the liquid crystal panel 9 are held by a metal frame 10 having a perforated display range of the liquid crystal panel 9.

According to the above configuration, the spatial distance between the reflector 7 and the fluorescent lamp 8 is kept uniform, and current leakage to the reflector 7 can be prevented. At the same time, unlike a sheet, the reflector itself can serve to protect the lamp from external impact.

Therefore, when the liquid crystal display device is to be made thinner, lighter, and brighter, the power consumption loss that occurs during lighting at a high frequency can be reduced, and the effect of holding the fluorescent lamp can be enhanced.

[0022]

As described above, according to the present invention, the spatial distance between the reflector and the fluorescent lamp is kept uniform, so that when the operating frequency is increased, the leakage current from the fluorescent lamp to the reflector is reduced. Power consumption loss can be reduced. In addition, since the fluorescent lamp can be reliably held by the reflector, it is possible to mechanically protect the fluorescent lamp. In addition, it is possible to form a reflector, which cannot be formed by a reflector made of a resin sheet, into a desired shape, and it is possible to obtain a reflector structure having a high reflectance.

As a result, it becomes possible to make the liquid crystal display device which is becoming stronger and thinner, lighter, consume less power and have higher brightness.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a lighting unit according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a liquid crystal display device using an illumination unit according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a configuration of a conventional lighting unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light guide plate 2 Reflector 3 Housing 4 Screw 5 Resin film sheet 6 Back cover 7 Reflector 8 Fluorescent lamp 9 Liquid crystal panel 10 Metal frame

Claims (3)

[Claims] 1. A light guide plate having light equalizing means for equalizing incident light for illuminating a liquid crystal panel from a back surface thereof, and the light guide plate is disposed on at least one side surface of the light guide plate and provided for the illumination. A fluorescent lamp that outputs divergent light,
A reflector that reflects the divergent light from the fluorescent lamp toward the light guide plate, a reflector that covers the back surface of the light guide plate, a resin film sheet that covers the surface of the light guide plate, and a frame on which these are mounted. A lighting unit, comprising: 2. The lighting unit according to claim 1, wherein the reflector uses a reflector having a configuration in which a metal plate having a thickness of 2 mm or less and an insulating reflector are attached to each other. 3. A liquid crystal display comprising the lighting unit according to claim 1, wherein a liquid crystal panel and a metal frame having a perforated display area of the liquid crystal panel are provided above the lighting unit. apparatus.