JPH08179321A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To miniaturize an illuminating means, to eliminate the unevenness of luminance and to facilitate the exchange of a light source. CONSTITUTION: One end of a reflection sheet 4 arranged around the light source so as to guide light from the light source 3 to a light transmission plate 2 is stuck and fixed on a frame body 8 by using an adhesive member such as adhesive or double coated adhesive tape through a hard and heat conductive plate 9 provided along one end of the plate 2 corresponding to the upper end of the side surface of the plate 2. The other end of the reflection sheet 4 is made a free end, which is pressed and fixed on a heat conductive body 5 on the base of the plate 2.

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 using an illumination means in which a light source is arranged on the side surface of a light guide plate.

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal display device, as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 5-72514, a liquid crystal panel and an illuminating means including a light guide plate and a light source arranged on the back surface of the liquid crystal panel are provided with a metal frame. It was supported and stored using the body to form a so-called module. In these modules, the lighting means is separately stored by a frame made of resin,
In many cases, the illuminating means and the liquid crystal panel can be handled independently by stacking the liquid crystal panel on the frame and storing it in a metal frame.

[0003]

However, the reflection sheet is soft and it is difficult to fix the light source so as to cover the light source with a predetermined curved surface. Further, the light source is usually a cold cathode tube or the like, but it is a little. However, since heat is released, when accumulated, it appears as background color unevenness and display contrast change in the liquid crystal panel, which is not preferable.

[0004]

The present invention has been made in view of the above points, and includes a frame body for positioning and arranging a light guide plate, a light source, and a reflection sheet, and the reflection sheet is provided along one end thereof. It is configured to be fixed to the frame through a hard plate provided.

Further, the liquid crystal display device of the present invention is arranged as a light guide plate on the back surface of the liquid crystal panel and has a heat conductor on the bottom surface, and the light source is a frame body for guiding the light to the light guide plate. The side surface of the reflection sheet is fixed to the frame body via a heat conductive plate, and the other end of the reflection sheet is placed in contact with the heat conductor on the bottom surface of the light guide plate.

[0006]

According to the liquid crystal display device using the illuminating means of the present invention, one end of the reflection sheet can be securely bonded and fixed to the frame body in a strip shape by a hard plate, and the fixing means is a heat conductor. By doing so, the heat dissipation characteristics are improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a main part of a liquid crystal display device according to an embodiment of the present invention, and FIGS. 2 to 4 are sectional views of a main part for explaining the assembly thereof. In the figure, reference numeral 1 denotes a twist nematic type or super twist nematic type liquid crystal panel having a polarizing plate 13 in which a liquid crystal layer 11 is sandwiched between two substrates 12, and a driving element 14 and a printed circuit board are provided around the driving element 14 as needed. The drive element 14 is of a tape automated bonding (TAB) type in which a semiconductor element is fixed to a flexible substrate, for example. In the peripheral portion of the liquid crystal panel 1, an elastic cushioning material 6 may be arranged, if necessary, in order to press a connecting portion with the drive element 14.

On the rear surface of the liquid crystal panel 1, an illuminating means and a resin frame 8 for positioning and accommodating the illuminating means are arranged. The illuminating means comprises a light guide plate 2, a light source 3 and a reflection sheet 4, and a heat conductor 5 is provided on the bottom surface of the light guide plate 2. The light guide plate 2 is made of a photoconductive plate made of acrylic resin or the like, on the surface of which a light diffusing plate 21 or a lens sheet is arranged, and on a bottom surface of which a reflecting sheet 22 is arranged. The light source 3 is a linear light source including a cold cathode fluorescent lamp and a fluorescent lamp, and is arranged along one side surface of the light guide plate 2 so as to be separated from the light guide plate 2. The reflection sheet 4 has flexibility and high reflectivity, and efficiently guides the light of the light source 3 to the light guide plate 2.
The light source 3 is surrounded without contacting the light source 3. Heat conductor 5
Is made of an aluminum thin plate with good heat dissipation that covers the bottom surface of the light guide plate 2, and is provided on the entire surface or a part of the light guide plate. However, in order to improve the heat distribution, It is provided so as to cover 1/3 or more, and is used together with a heat equalizing plate (not shown) made of a resin sheet or the like, if necessary.

The frame body 8 which supports the liquid crystal panel 1 and houses the illumination means is made of a resin molded product or the like, and these are housed in a metal frame body. The frame body 8 is composed of an upper frame 81 having locking means for mutually fixing and a bottom frame 82 that covers at least the light source 3 from the bottom surface, if necessary. The light source 3 is fixed at both ends by fitting a code supporter into the recesses 811 (see FIG. 3b) of the upper frame 81, and is covered by the bottom frame 82. Further, the upper frame 81 is configured such that the main surface is located between the liquid crystal panel 1 and the illuminating means, and is located substantially in the center so as to guide the light emitted from the surface of the light guide plate 2 to at least the effective display surface of the liquid crystal panel 1. It has a through hole. On the back surface of the upper frame 81, one end of the reflection sheet 4 is made to correspond to the upper end of the side surface of the light guide plate 2, and is attached to the frame body 8 via a hard and thermally conductive plate 9 provided along the one end. It is fixed by adhesion using an adhesive or an adhesive member such as double-sided tape. The plate 9 is made of, for example, an aluminum plate and is long and flat.
First, as shown in abc, it is adhered to the reflection sheet 4, and then it is adhered to the flat portion provided between the concave portions 811, and then the light guide plate 2 is inserted, and heat conduction is performed as shown in FIGS. 3 and 4. The body 5 is placed and the light source is incorporated.

As described above, since the reflection sheet 4 is adhered by being supported by the plate 9 on the back surface of the upper frame 81, the reflection sheet 4 is adhered and fixed on the upper surface of the light guide plate without the light diffusing plate 21 as in the conventional case. Compared with the case, the width of the light guide plate 2 can be set shorter,
The illumination means can be miniaturized. In other words, since the bonding margin of the reflection sheet 4 on the upper frame 81 is located above the light source 3 and has a planar overlap with the light source 3, it is possible to set the width dimension of the illumination means short. It can be said that it is possible. The other end of the reflection sheet 4 may be a free end or may be adhered to the heat conducting plate 5 on the bottom surface of the light guide plate, but preferably the lamp unit is the light source 3 and the wiring plate 31 which is the wiring means thereof. It is preferable to press and fix with a wiring board 31 composed of a printed circuit board or the like having a strip-shaped conductor having a large area, and in any case, if the other end is placed in contact with the heat conductor 5 on the bottom surface of the light guide plate, it becomes high. It is preferable because an efficient heat dissipation path is formed.

[0011]

As described above, according to the liquid crystal display device using the illuminating means of the present invention, one end of the reflection sheet is fixed to the frame body so as to correspond to the upper end of the side surface of the light guide plate. It is possible to eliminate the need for an adhesive margin for attaching the light guide plate, reduce the width of the light guide plate, and reduce the size and weight of the illumination unit and the display device using the illumination unit. further,
By eliminating the adhesive layer between the light guide plate and the reflection sheet, the reflection characteristics can be improved and the uneven brightness can be improved.
Since it is not necessary to bond the other end of the reflection sheet to the light guide plate,
It is possible to easily perform the replacement work without the need to remove or attach the reflection sheet when exchanging the light source, and it is possible to prevent an accident that damages the reflection sheet during the replacement. It is more characteristic that one end of the reflection sheet can be fixedly bonded and fixed to the frame body linearly with a hard plate, and the heat dissipation property is improved by using a heat conductor as the fixing means. As a result, not only was the curved surface of the reflection sheet formed nicely, the light reflection characteristics were good, and the light was efficiently guided to the light guide plate, and the background color unevenness and display contrast change in the liquid crystal panel were significantly alleviated due to heat dissipation.

[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.

FIG. 2 is a sectional view of an essential part abc for explaining assembly of the embodiment.
Is.

FIG. 3 is a cross-sectional view (a) and a rear view (b) of an essential part for explaining the assembly of the embodiment.

FIG. 4 is a rear view ab explaining the assembly of the embodiment.

[Explanation of symbols]

 1 Liquid crystal panel 2 Light guide plate 3 Light source 4 Reflective sheet 5 Thermal conductor 8 Frame

Front page continuation (72) Inventor Renichi Keiichi Tottori City, Tottori City, 3-201 Minamiyoshikata, Tottori Sanyo Electric Co., Ltd. (72) Inventor Takeshi Inoue 3-201 Minamiyoshikata, Tottori City, Tottori Prefecture Tottori Sanyo Electric Co., Ltd.

Claims (2)

[Claims] 1. A liquid crystal panel, a light guide plate arranged on a back surface of the liquid crystal panel, a light source arranged along a side surface of the light guide plate, and a light source of the light source for guiding light of the light source to the light guide plate. A reflection sheet arranged around, the light guide plate, the light source,
A liquid crystal display device, comprising: a frame body for positioning and arranging a reflection sheet, wherein the reflection sheet is fixed to the frame body via a hard plate provided along one end thereof. 2. A liquid crystal panel, a light guide plate arranged on the back surface of the liquid crystal panel and having a heat conductor on the bottom surface, a light source arranged near the light guide plate, and the light from the light source. In a liquid crystal display device comprising a frame body that supports a light source along a side surface of the light guide plate so as to guide the light source, and a reflection sheet arranged around the light source so as to guide the light of the light source to the light guide plate, The liquid crystal display device is characterized in that one end of the reflection sheet is fixed to the frame body via a heat conductive plate, and the other end is arranged in contact with the heat conductor on the bottom surface of the light guide plate.