JPH05323317A - Lighting unit and liquid crystal display device using the same - Google Patents

Abstract

PURPOSE:To exert no adverse influence on lighting characteristics of a fluorescent tube even when an edge light type lighting unit employs a system enabling the fluorescent lamp to easily be replaced and uses a reflecting film using a metallic film, etc. CONSTITUTION:The reflecting film 4 is fixed on an end surface of a light guide plate 1 with an adhesive 5, flexible spacers 6 of silicone rubber, etc., are stuck on two points of at least both side end parts on short-side sides of the reflecting film and surrounded with the reflecting film 4 so that the spacers are positioned behind the fluorescent tube 7 arranged on the flank of the light guide plate 1, and a resin cover 9 is arranged above it to press and hold the reflecting film 4 to the light guide plate 1. The flexible spacers 6 are used within <=2/3 times as long as the circumference of the fluorescent tube 7 and 0.5-2mm thick.

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 in a transmissive display device and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have come to be widely used in display devices for information equipment such as laptop type or notebook type word processors or personal computers because of their light weight, thinness and low power consumption. It was Further, as a recent tendency, the liquid crystal display device having a built-in illumination unit has come to occupy most with the improvement of brightness and colorization of the liquid crystal display screen. This lighting unit is roughly classified into a direct type that uses a uniformizing means such as a lighting curtain and an edge light type that uses a light guide plate. Recently, with the spread of notebook type word processors and personal computers, edge lights have become popular. There are many types.

FIG. 4 shows a sectional view of an edge light type lighting unit. Usually, in the edge light type lighting unit, in order to effectively utilize the light emission from the fluorescent tube, the fluorescent tube arranged on the side surface of the light guide plate is wrapped with a reflective film, and the long side end portions of the reflective film are Adhesive fixing is applied to both sides of the light guide plate. In addition, there are some monochromatic type liquid crystal display devices in which the brightness of the illumination unit may be about 300 to 600 cd / m ² without a reflective film, but like the color liquid crystal display device, the transmittance of the liquid crystal panel is low. Low is 2
A reflective film is indispensable because it requires a brightness of around 000 cd / m ² . A white film with high reflectance is often used as the reflection film, but recently, a polyester film with silver (Ag) vapor deposition has been used as the high reflectance film for obtaining high brightness. Came.

[0004]

However, in the illumination unit as shown in the conventional example, there is a problem that the fluorescent film cannot be easily replaced because the reflective film surrounds the fluorescent tube and is adhered to the light guide plate. Generally, it is said that the life of the fluorescent tube is the shortest as the life of the liquid crystal display device. Therefore, replacement of the fluorescent tube is indispensable, and a structure that can be easily replaced has been demanded. In addition, a reflection film using a high-reflectance metal film such as silver (Ag) has come to be used for an illumination unit for a color liquid crystal device that requires high brightness. When the fluorescent tube is close to the fluorescent tube, the lighting characteristics of the fluorescent tube may be abnormal, and it is important to accurately maintain a certain distance between the reflective film and the fluorescent tube.

The present invention has been made in view of the above points, and even in an edge light type lighting unit using a reflection film, a method in which a fluorescent tube can be replaced very easily and a metal film is used. It is an object of the present invention to provide a method that does not adversely affect lighting characteristics even when a reflective film is used.

[0006]

In order to achieve this object, the present invention provides that one end of the reflection film on the long side along the fluorescent tube is attached to the end of the light exit surface of the light guide. And a flexible spacer is attached to the inside of a plurality of locations including both ends on the short side of the reflective film to enclose the fluorescent tube, and the other end on the long side of the reflective film is attached to the back surface of the light guide. It is pressed and held by a resin cover.

[0007]

With this structure, one side of the reflection film is opened by removing the resin cover pressed and held, and the fluorescent tube can be easily removed and replaced. In addition, by attaching a flexible spacer to the inner surface of the reflective film, it is possible to always maintain a gap in the spacer thickness between the fluorescent tube and the reflective film using a metal film, etc. It is now possible to provide a high brightness lighting unit.

[0008]

Embodiments of the present invention will be described in detail below with reference to the drawings. (FIG. 1) (a) and (b) show a sectional view and a plan view of an illumination unit of the present invention. In the figure, the light guide 1
A pattern for equalizing the light is formed on the back surface of, and the reflection plate 2 is arranged on the surface. Further, a diffusion plate 3 is arranged on the outgoing light surface of the light guide plate 1, and an end surface of the reflection film 4 is fixed to the end portion of the light guide plate 1 with an adhesive 5 such as a double-sided tape.

Flexible spacers 6 made of silicon rubber or the like are attached to two points at least at both ends on the short side of the reflection film 4, and the rear surface of the fluorescent tube 7 disposed on the side surface of the light guide plate 1 is attached. It is configured to be wrapped with the reflection film 4 so as to come to the portion. Generally, a film having a high reflectance is used as the reflection film 4, but in the present embodiment, a film having a higher reflectance is formed by forming a thin film of silver (Ag) on a polyester film or the like. The flexible spacer 6 attached to the reflective film 4 has a length of not more than two-thirds of the circumference of the fluorescent tube, a thickness of 0.5 to 2 mm, and a width of 2 to 5 mm although not specified. I used one.

This is to be attached so as to leave a space so that the fluorescent tube and the reflection film do not come into contact with each other. However, if the length of the spacer is longer than the above-mentioned dimension, the fluorescent surface of the fluorescent tube becomes uneven. is important. It is better to increase the number of flexible spacer attachment points as the length of the fluorescent tube increases.

FIG. 2 shows a structure for pressing and holding the reflection film having the structure shown in FIG. (FIG. 2) (a) and (b), the light guide plate 1 and the like are installed in the resin frame body 8, and the reflection film 4 enclosing the fluorescent tube 7 is pressed by the resin cover 9, and both ends thereof are formed in the resin frame body. 8
It is fixed to the side with screws 10. When replacing the fluorescent tube 7,
If the screw 10 is removed and the resin cover is removed, the reflection film 4 is lifted and the fluorescent tube 7 can be easily replaced.

Next, FIG. 3 shows a sectional view of a liquid crystal display device according to a second embodiment of the present invention. In the figure, an illumination unit composed of a light guide 1 having a light equalizing means, a fluorescent tube 7 and a reflection film 4 encapsulating the fluorescent tube 7 is arranged under a resin frame 8 and a resin cover is provided. 9
Thus, the fluorescent film 7 and the entire reflective film 4 are mechanically protected by pressing on the reflective film 4, and the lighting unit is held by the resin frame 8. Resin frame 8
At the top of the panel, the liquid crystal panel 11 and the TAB connected to it
(Tape Automatede Bonding) Mounted driver L
A liquid crystal module composed of the SI 12 and the bus circuit board 13 is installed. In the present invention, the position where the fluorescent tube is arranged is the segment side of the liquid crystal module. Further, a metal frame 14 having an opening in the display area of the liquid crystal module is installed above the liquid crystal module to mechanically protect the circuit components such as the driver LSI 12 around the liquid crystal panel, and the side surface of the metal frame 14 prevents resin from being applied. The cover 9 and the resin frame 8 are firmly held by the caulking portion 15.

When replacing the fluorescent tube of the liquid crystal display device having the above structure, the caulking portion 15 of the resin cover 9 is released,
Further, by removing the screw fixing the resin cover (see FIG. 2) and removing the resin cover 9, the end of the reflection film 14 on the reflection plate side of the light guide plate 1 floats, and the fluorescent tube can be replaced.

[0014]

As described above, according to the present invention, when the fluorescent tube disposed on the side surface of the light guide body is replaced, the fluorescent tube is conventionally simply attached because the reflection film is adhered to the light guide plate. By solving the problem that it cannot be removed, it has become possible to replace the fluorescent tube very easily. Also, regarding the problem that the lighting characteristics of the fluorescent tube become abnormal when a reflective film with a high reflectance using a metal film comes into contact with or comes close to the fluorescent tube, by attaching a flexible spacer to the reflective film, it is possible to maintain a constant interval. It is possible to keep the LED between the fluorescent tube and the reflective film, and it is possible to obtain stable lighting characteristics.

In addition, in a liquid crystal display device using this illumination unit, the resin cover covering the fluorescent tube and the reflection film is firmly held by the caulking of the metal frame to mechanically protect it from impacts and the like. When replacing the fluorescent tube, the resin cover can be easily removed by replacing the caulking portion of the metal frame.

[Brief description of drawings]

FIG. 1 is a sectional view and a plan view (front surface) of a lighting unit (without a resin frame and a resin cover) of the present invention.

FIG. 2 is a sectional view and a plan view (back side) of the lighting unit of the present invention.

FIG. 3 is a sectional view of a liquid crystal display device of the present invention.

FIG. 4 is a sectional view of a conventional lighting unit (edge light system).

[Explanation of symbols]

 1 Light guide plate 4 Reflective film 5 Adhesive 6 Flexible spacer 7 Fluorescent tube 8 Resin frame 9 Resin cover

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuo Nomura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A light guide body provided with light equalizing means, a fluorescent tube disposed on a side surface portion of the light guide body, and a reflection film enclosing the fluorescent tube and holding the side surface portion of the light guide body. One end of the long side along the fluorescent tube is attached to the end of the light exit surface of the light guide, and the inside of a plurality of locations including at least both ends on the short side of the reflective film. An illumination unit, wherein a flexible spacer is attached to wrap the fluorescent tube, and the other end of the long side of the reflective film is pressed and held against the back surface of the light guide plate by a resin cover. 2. A flexible spacer attached to the inside of the reflective film is arranged on the side surface of the light guide plate in a length of not more than two thirds of the circumference of the fluorescent tube and a thickness of 0.5 to 2 mm. The lighting unit according to claim 1, wherein the lighting unit is configured to be in contact with the back surface of the fluorescent tube. 3. A light guide body provided with light equalizing means, a fluorescent tube arranged on a side surface portion thereof, a reflection film enclosing the fluorescent tube and holding the side surface portion of the light guide body, and a resin cover for pressing the reflection film. , And a lighting unit formed of a resin frame body that holds all the members, a liquid crystal module and a metal frame in which a display range of the liquid crystal module is opened on the upper part of the lighting unit, and the side portion of the metal frame A liquid crystal display device characterized by holding a resin cover and a resin frame. 4. The liquid crystal display device according to claim 3, wherein the fluorescent tube of the illumination unit is arranged below the segment side drive circuit of the liquid crystal module.