JPH06235822A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve the adhesion of a reflection sheet of the liquid crystal display device having an illuminating means on the rear surface of a liquid crystal cell and to enable the efficient exchange of a light source by disassembly of a lamp house even in exchange of this light source by pressing one end of the reflection sheet to a light transmission plate and pressing the reflection sheet by tongue-shaped parts formed at the lamp house or front panel. CONSTITUTION:The reflection sheet 4 pressed to the surface of a light transmission plate 2 is pressed by the tongue-shaped parts 51 formed at the lamp house 5 or the front panel 6. For example, the lamp house 5 is formed to a cylindrical shape of an approximately U-shape in section and is formed with the mounting tongue-shaped parts at both ends and is fixed to the light transmission plate 2 by means of screws penetrating these mounting tongue-shaped parts. The reflection sheet 4 is pressed and fixed via a bar-shaped resin 7, etc., consisting of a polycarbonate resin by the tongue-shaped parts 51 provided at the lamp house 5 in approximately the central part of the surface of the light transmission plate 2 at this time. As a result, the reflection sheet 4 is adhered and fixed to the light transmission plate 2 and the light source 3 is easily exchanged by disassembly of the lamp house even in the exchange of the light source 3.

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 having illumination means on the back surface of a liquid crystal cell.

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal display device, a liquid crystal cell and an illuminating means are laminated as shown in Japanese Patent Laid-Open No. 3-194515, and the illuminating means is arranged on the back surface of the liquid crystal cell. It is composed of a light guide plate and a linear light source arranged on the side surface of the light guide plate.The light source is covered with a reflection sheet in order to enhance the light utilization efficiency, and both ends of the reflection sheet are bonded to the front and back edges of the light guide plate. There is.

[0003]

However, the light source has the shortest life in such a liquid crystal display device, and the reflection sheet must be removed in order to replace the light source with a reduced light amount. Since a substitute reflection sheet has to be fixed later, the entire illuminating means must be removed from the frame after all, which is a complicated task. Therefore, we investigated a method of not bonding the reflection sheet to the light guide plate, but it was difficult to fix the edge of the reflection sheet to the light guide plate because the light source is relatively long and the width of the reflection sheet is wide. . And the utilization efficiency of light changes depending on whether the reflection sheet comes into contact with or separates from the light guide plate, uneven display illuminance is likely to occur, and especially when the heat from the light source stays inside the reflection sheet due to long usage time, The reflection sheet that was in contact with the light guide plate and the light guide plate are separated from each other, and the light is locally darkened.

[0004]

The present invention has been made in view of the above points, and includes a light guide plate arranged on the back surface of a liquid crystal cell, a light source arranged on the side surface of the light guide plate, and a light source. A reflecting sheet for covering, a lamp house for accommodating the light source and the reflecting sheet, and a front panel for covering the liquid crystal cell are provided. One end of the reflecting sheet is in contact with the light guide plate, and a tongue piece formed on the lamp house or the front panel. It is pressed by the part.

[0005]

As a result, the reflection sheet is pressed and fixed to the light guide plate as the liquid crystal cell or the lamp house is fixed, so that the reflection sheet adheres well and the lamp house can be efficiently replaced by disassembling the lamp house.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view of an essential part of a liquid crystal display device according to an embodiment of the present invention, in which reference numeral 1 denotes a liquid crystal cell of twisted nematic type or super twisted nematic type. Elements, conductive rubber connected to the drive circuit board, wiring material such as heat seal, and the like are provided. Reference numeral 2 denotes a light guide plate disposed on the back surface of the liquid crystal cell 1, which is made of acrylic resin having a back surface provided with spotted white ink or a reflective coating, or a laminate thereof.
The speckled white ink makes the reflection of light uniform, and the reflective coating enhances the light utilization efficiency obtained by multicolor printing.A surface with uniform illuminance is provided together with a diffusion sheet on the surface if necessary. It is for lighting. Reference numeral 3 denotes a light source which is arranged on the side surface of the light guide plate 2 in parallel with the side of the light guide plate with a small clearance, and is composed of a cold cathode tube or a fluorescent lamp. Reference numeral 4 denotes a reflection sheet that covers the light source 3. The reflection sheet 4 is made of an aluminum sheet or the like, and has one end adhered to the back surface of the light guide plate 2 and the other end abutted on the surface of the light guide plate 2. Reference numeral 5 denotes a lamp house which houses the light source 3 and the reflection sheet 4 and supports the light source 3 and the reflection sheet 4 at both ends of the light source. Reference numeral 6 denotes a front panel which covers the liquid crystal cell 1, each of which is formed of a metal plate or the like.

In the above-mentioned structure, the reflection sheet 4 contacting the surface of the light guide plate 2 is pressed by the tongue piece portion 51 formed on the lamp house 5 or the front panel 6. For example, the lamp house 5 has a tubular shape with a substantially U-shaped cross section having a thickness of 0.5 mm, is formed with mounting tongue portions at both ends, and is fixed to the light guide plate 2 with screws penetrating the mounting tongue portions. However, at this time, the reflecting sheet 4 is pressed and fixed by the protruding tongue piece portion 51 provided in the substantially central portion on the front surface side of the light guide plate 2 via the rod-shaped resin 7 or rubber made of polycarbonate resin having a thickness of 1.0 mm or rubber. It is a thing. As a result, the reflection sheet 4 is tightly fixed to the light guide plate 2, and even if heat from the light source is transmitted, the light inside the reflection sheet can be efficiently guided from the edge of the light guide plate to the inside of the light guide plate. Although the example of providing the tongue portion in the lamp house has been described, the tongue portion may be provided in the front panel 6 when the edge of the front panel 6 that houses the liquid crystal cell 1 is located near the light source 3.

[0008]

As described above, since the reflection sheet is pressed and fixed to the light guide plate by the front panel or the lamp house as the liquid crystal cell or the light source is fixed, the reflection sheet is well adhered.
Even when replacing the light source, it can be replaced efficiently by disassembling the lamp house.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Liquid crystal cell 2 Light guide plate 3 Light source 4 Reflective sheet 5 Lamp house 51 Tongue part 6 Front panel

Claims (1)

[Claims] 1. A liquid crystal cell, a light guide plate arranged on the back surface of the liquid crystal cell, a light source arranged on the side surface of the light guide plate, a reflection sheet for covering the light source, and a lamp house for accommodating the light source and the reflection sheet. With a front panel that covers the liquid crystal cell,
One end of the reflection sheet is in contact with the light guide plate and is pressed by the tongue piece formed on the lamp house or the front panel.