JPH0659131A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To stabilize the brightness of a light emitting body in a short period of time by interposing an insulating material into the required part between the light emitting body and a reflection sheet to put the light emitting body and the reflection sheet into a contactless state. CONSTITUTION:Spacer rings 8 consisting of a heat resistant insulating material and transparent material are provided near both ends of the light emitting body 2. The spacer rings 8 are formed to a shape partly notched in such a manner that these rings can be attached and detached to and from the light emitting body 2. The reflection film 7 is provided by being wound around the spacer rings 8. A spacing is, therefore, formed between the reflection film 7 and the light emitting body 2 by the intervention of the spacer rings 8, by which the light emitting body 2 and the reflection film 7 are put into the electrically contactless state. The material of the spacer rings 8 is exemplified by transparent silicone rubber, etc. The spacer rings 8 are formed to the approximately partly notched annular shape in such a case and for practicable use, the spacer rings may be provided only in the parts where the reflection film 7 comes into contact therewith and may be formed to an approximately semicircular shape. Then, the leak current from the light emitting body 2 is eliminated and a lighting property is stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used as a display portion of various electronic devices, and more particularly to a sidelight type backlight type liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display device used as a display portion of various electronic devices does not have a light emitting function by itself and uses outside light, but the display is difficult to see if the brightness is not sufficient. Therefore, liquid crystal display devices, which have a backlight and are easy to see even in a dark place, are now in widespread use.

The backlight includes a direct type and a sidelight type. The direct type is provided with a light emitting body 2 such as a cold cathode fluorescent tube or a hot cathode fluorescent tube behind a liquid crystal display panel 1 as shown in FIG. The liquid crystal display panel 1 is illuminated by the light emitting body 2.
In the side light type, as shown in FIG. 4, a light emitting plate 3 made of acrylic resin or the like is provided behind the liquid crystal display plate 1, and a light emitting body 2 is disposed on a side end surface of the light emitting plate 3, and the light emitting body 2 is provided. Light is made incident from the side end surface of the light emitting plate 3, and the light reflected by the entire surface of the light emitting plate 3 is irradiated to the liquid crystal display plate 1.

A conventional side light type backlight type liquid crystal display device will be described with reference to FIGS.

The light emitting plate 3 is provided with a reflecting plate 4 on the back surface of the light guide plate 6.
Is provided, and a diffusion plate 5 is provided on the front side of the light guide plate 6. The light emitting body 2 is disposed on the end face of the position of the light emitting plate 3, and the light emitting body 2 emits the light. The light emitting plate 3 is formed by the reflection film 7 wrapped around the body 2.
It is integrated with. A metal is vapor-deposited on the surface of the reflective film 7.

A part of the light emitted by the light emitting body 2 is directly incident on the light guide plate 6, and the rest is reflected by the reflection film 7 and is incident on the light guide plate 6.

The light incident on the light guide plate 6 is reflected by the reflection plate 4 and the like, diffused over the entire surface of the light emitting plate 3, further homogenized by the diffusion plate 5, and emitted to the liquid crystal display plate 1.

[0008]

As described above, in the conventional liquid crystal display device of the sidelight type backlight system, the reflective film 7 having the metal film deposited thereon is wrapped around the light emitting body 2, and therefore the light emitting body 2 is used. The leak current flowing on the surface of the is absorbed by the reflective film 7. Therefore, there is a problem that it becomes difficult for the light emitting body 2 to light up, and it takes time until the luminance of the light emitting body 2 becomes stable.

In view of the above situation, the present invention aims to stabilize the luminance of the light emitting body in a short time.

[0010]

According to the present invention, a light-emitting body is arranged on one end side of a light-emitting plate, and light from the light-emitting body is supplied to the one side of the light-emitting plate.
In a liquid crystal display device in which a reflection sheet leading to an end face is wrapped around the light emitting body, an insulating material is interposed at a required portion between the light emitting body and the reflection sheet, so that the light emitting body and the reflection sheet are not in contact with each other. It is characterized by having done.

[0011]

The light-emitting body and the reflection sheet are brought into non-contact with each other to reduce the leakage of current from the light-emitting body and increase the brightness stability during lighting.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the same parts as those shown in FIG. 5 are designated by the same reference numerals.

Spacer rings 8 made of a heat-resistant insulating material and a transparent material are provided near both ends of the light emitting body 2. The spacer ring 8 has a shape in which a part thereof is cut out so that the spacer ring 8 can be fitted into and removed from the light emitting body 2. The reflective film 7 is the spacer ring 8
It is installed around. Therefore, a space is formed between the reflective film 7 and the light emitting body 2 by interposing the spacer ring 8, and the light emitting body 2 and the reflective film 7 are brought into an electrically non-contact state.

Examples of the material of the spacer ring 8 include transparent silicone rubber and the like. The thickness is 1 mm and the width is 5 mm.
mm is enough. Further, the spacer ring 8 shown in the figure has a substantially ring shape with one part cut away, but in practical use, only the portion in contact with the reflection film 7 may be used, and it may have a substantially semicircular shape.

Reference numerals 9 and 10 denote electrodes.

In this embodiment, the reflection film 7 and the light emitter 2
Since and are in a non-contact state, the leak current from the light emitting body 2 is eliminated, and the lighting property is stabilized. Thus, a brightness of about 90% is obtained in about 5 minutes after power is applied to the liquid crystal display device, which is an improvement of about 20% as compared with the conventional one.

The thickness and width of the spacer ring 8 may be appropriately selected according to the size of the liquid crystal display device and the material is not limited to silicone rubber.

[0019]

As described above, according to the present invention, the leak current from the light emitting body is reduced, the brightness stabilization time from lighting can be shortened, and the brightness is stabilized early so that the display at the initial stage of the work is easy to see. At the same time, the brightness adjustment work of the liquid crystal display device at the beginning of the work can be facilitated.

[Brief description of drawings]

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

FIG. 2 is a perspective view taken along the line AA of FIG.

FIG. 3 is an explanatory diagram showing a direct-type backlight type liquid crystal display device.

FIG. 4 is an explanatory diagram showing a liquid crystal display device of a sidelight type backlight system.

FIG. 5 is a partial perspective view of a conventional side-light-type backlight-type liquid crystal display device.

[Explanation of reference numerals] 1 liquid crystal display plate 2 light emitting body 3 light emitting plate 4 reflecting plate 5 diffusing plate 6 light guide plate 7 reflecting film 8 spacer ring

Claims (1)

[Claims] 1. A liquid crystal display device in which a light emitting body is arranged on one end side of a light emitting plate, and a reflection sheet for guiding light from the light emitting body to one end surface of the light emitting plate is wrapped around the light emitting body. A liquid crystal display device, characterized in that an insulating material is interposed in a required portion between the light emitter and the reflection sheet so that the light emitter and the reflection sheet are not in contact with each other.