JPH1010325A - Back light device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the rigidity of a light guide plate and to prevent the failure of a liquid crystal panel by the light guide plate subjected to impact without sacrificing the other characteristics of this plate by embedding a reinforc ing material in a direction perpendicular to a cold cathode tube into the light guide plate. SOLUTION: The cold cathode tube 3 and a reflector 4 are arranged on the one flank of the light guide plate 1 in a sectional view at an A-A' line. In such a case, the plate 1 is bisected by a line perpendicular to the cold cathode tube 3. The reinforcing late 2 of the same size as the size of the parting plane is inserted into the bisected parts and is adhered to the respective divided two light guide plate paths 1. The plate 1 is made of acryl and is adhered with reinforcing plate 2 by the acrylic adhesive to the tagged parts of the plate 1 divided at the center. The reinforcing material composed of the material having the high rigidity is embedded into the plate 1 in such a manner, by which the rigidity over the entire part of the plate 1 is enhanced. The bending of the plate 1 by the impact, etc., is obviated and the crack and failure of the liquid crystal panel are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight device for a liquid crystal display device, and more particularly to an edge light type backlight device.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view of a conventional liquid crystal display. As shown in the figure, a printed wiring board 6 is arranged around a liquid crystal panel 5, and a TCP (Tape Carrier Package) having a driver IC 8 mounted between the two.
7 is connected. Below the liquid crystal panel 5, a backlight device including the light guide plate 1, the cold cathode tube 3, and the reflector 4 is arranged. These outer peripheries are surrounded by an outer frame 9.

[0003] Liquid crystal display devices are aiming for thinner, lighter, and larger screens, and in order to realize these, it is necessary to reduce the thickness, weight, and size of liquid crystal panels and backlight devices. However, even if it is optically and electrically satisfactory, if you try to achieve both thinner and lighter and larger screen,
The stiffness and strength are structurally insufficient only by extension of the conventional technology. In particular, since the light guide plate used for the edge light type backlight device is wide and thin, the rigidity is reduced, and the light guide plate itself is bent by a force such as an impact, and contacts the liquid crystal panel positioned on the light guide plate. The same tendency is applied to the liquid crystal panel, and the mechanical strength of the liquid crystal panel is lowered. To reinforce the rigidity of the light guide plate, Japanese Patent Application Laid-Open No. 4-56822 proposes disposing a reinforcing frame 5 on the back side of the light guide plate 1 as shown in FIG.

[0004]

In the conventional example shown in FIG. 5, as described above, the rigidity of the light guide plate is reduced due to the reduction in thickness and the screen size, and the strength of the liquid crystal panel is reduced.
There has been a problem that the light guide plate is bent by an impact or the like and the panel is damaged. In addition, in the conventional example shown in FIG. 6, although the movement of the light guide plate toward the back side is restricted, the movement toward the liquid crystal panel is not restricted. Therefore, this structure effectively prevents panel breakage. I couldn't. Also,
In this conventional example, since the thickness increases by the reinforcement frame,
This would go against the trend of thinner devices. Therefore, the problem to be solved by the present invention is to increase the rigidity of the light guide plate without increasing the overall thickness, to suppress the warp of the light guide plate due to a force such as impact, and to improve the liquid crystal panel. The purpose is to prevent cracking and breakage.

[0005]

The above object can be attained by embedding a reinforcing member in a direction perpendicular to an illumination tube (cold cathode tube) in a light guide plate.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A backlight device according to the present invention includes a light guide plate and a cold cathode tube arranged on one side of the light guide plate. And a reinforcing material in a direction perpendicular to the direction is embedded.

[0007] The reinforcing material can be embedded in the light guide plate as follows. The light guide plate is divided into a plurality of portions in a direction perpendicular to the cold cathode tubes, and a reinforcing material is inserted between the divided light guide plates and bonded. A reinforcing material is embedded at the time of molding the resin plate serving as the light guide plate. As the material of the reinforcing material, a light guide plate material (for example, acrylic)
Any material having higher rigidity can be used, but preferably a metal material (metal plate, metal bar or metal bar) is used.

[Operation] Since the reinforcing member made of a material having high rigidity is embedded in the light guide plate, the rigidity of the entire light guide plate is increased. Therefore, the light guide plate does not bend due to an impact or the like, and the liquid crystal panel can be prevented from being broken or damaged. Further, since the reinforcing member is at right angles to the cold cathode tube, the light emitted from the cold cathode tube is hardly blocked, and the thickness of the backlight device is the same as the thickness of the light guide plate itself.

[0009]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA 'of FIG. As shown in FIGS. 1 and 2, a cold cathode tube 3 and a reflector 4 are arranged on one side surface of the light guide plate 1. In this embodiment, the light guide plate 1 is divided into two parts by a line perpendicular to the cold cathode tube 3. A reinforcing plate 2 having the same size as the dividing surface is inserted into the divided portion, and is bonded to each of the two divided light guide plates 1.

The light guide plate 1 has a length of 222 m in the AA 'direction.
m, length 172 mm, thickness 4 mm perpendicular to AA ′
And 0.7mm thick aluminum (JI
A reinforcing plate 2 of A5052P-H24 material specified by SH4040) is adhered to the divided portion of the light guide plate 1 divided at the center by an acrylic adhesive. A of light guide plate 1
−A ′ are fixed at two sides, and the center of the light guide plate 1 is
The displacement of the light guide plate 1 when a load of 3 kg is applied at 1 mmφ is 1
mm. On the other hand, when the same test as described above was performed using a light guide plate of the same size without a reinforcing plate, the displacement of the light guide plate was 2 mm.

FIG. 3 is a perspective view showing a second embodiment of the present invention. As shown in FIG. 3, the light guide plate 1 is divided into three, and two reinforcing plates 2 are inserted into the divided portions of the light guide plate 1 and adhered. In this embodiment, since the number of reinforcing plates is increased, the structure is higher in rigidity than in the first embodiment. Alternatively, it has a structure that can support a light guide plate having a wider area. As described above, the number of the reinforcing plates 2 can be appropriately increased as needed. The material of the reinforcing plate 2 may be any material as long as it has higher rigidity than the light guide plate 1. In general, a metal is preferable and an alloy such as stainless steel may be used.

FIG. 4 is a sectional view showing a third embodiment of the present invention. In this embodiment, as shown in FIG. 4, two reinforcing plates 2 are embedded in the light guide plate 1 so as not to be exposed on the surface. The size of the light guide plate is the same as that of the first embodiment, and an aluminum reinforcing plate 2 having a thickness of 0.7 mm and a width of 3 mm is embedded therein. The light guide plate of the present embodiment is formed by embedding an aluminum plate therein when forming an acrylic plate serving as a light guide plate. In this embodiment, a square or round bar (wire) made of metal or the like can be used instead of the aluminum reinforcing plate.

[0013]

As described above, since the backlight device of the present invention has the reinforcing member in the direction perpendicular to the cold cathode tube embedded in the light guide plate, it does not increase the thickness of the light guide plate. Further, it is possible to increase the rigidity of the light guide plate while reducing the light emitted from the cold cathode tubes.
Therefore, according to the present invention, it is possible to prevent an accident that the light guide plate damages the liquid crystal panel due to an impact or the like without sacrificing other characteristics.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along the line AA ′ of FIG. 1;

FIG. 3 is a perspective view of a second embodiment of the present invention.

FIG. 4 is a sectional view of a third embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional liquid crystal display device.

FIG. 6 is a cross-sectional view of a conventional light guide plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light guide plate 2 Reinforcement plate 3 Cold cathode tube 4 Reflector 5 Liquid crystal panel 6 Printed wiring board 7 TCP 8 Driver IC 9 Outer frame 10 Reinforcement frame

Claims (4)

[Claims] 1. A backlight device for a liquid crystal display device including a light guide plate and an illumination tube disposed on one side of the light guide plate, wherein a reinforcing material in a direction perpendicular to the illumination tube is embedded in the light guide plate. A backlight device characterized in that the backlight device is provided. 2. The backlight device according to claim 1, wherein the light guide plate is divided into a plurality of portions in a direction perpendicular to the illumination tube, and a reinforcing member is inserted and bonded between the divided light guide plates. . 3. The light guide plate according to claim 1, wherein the reinforcing material is embedded without being exposed on the surface of the light guide plate.
The backlight device as described in the above. 4. The backlight device according to claim 1, wherein the reinforcing member is formed of a metal plate, a metal bar, or a metal rod.