JP2002156512A - Backlight reflection plate for liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection plate having no problem of uneven brightness generation due to deformation or the like and of illuminance lowering due to induced radio wave generation or the like, producing no wasted material in manufacturing, being easily manufactured at a low cost and, furthermore, easily dealing with diversification of liquid crystal screen sizes and increase and decrease of light sources. SOLUTION: In the reflection plate, being a backlight reflection plate for a liquid crystal display device and having a reflection layer formed on a surface of a substrate which is formed in a repeatedly inflected shape, the substrate is constructed with a deformed extrusion molded part composed of a synthetic resin and the reflection layer is constructed with a synthetic resin film processed so as to heighten reflection efficiency or with a coating applied to the substrate surface exhibiting high reflection efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight reflector for a liquid crystal display device, and more particularly, to a direct type backlight device for a liquid crystal display device, which is disposed behind a light source for illuminating the liquid crystal display panel. The present invention relates to a reflection plate for reflecting light from a reflector.

[0002]

2. Description of the Related Art As a backlight device used for a liquid crystal display device, there are a direct type in which light from a light source is directly illuminated on a liquid crystal display panel, and a liquid crystal panel through a light guide plate made of acrylic resin or the like. There is a sidelight system that illuminates the LCD, but with the recent increase in the size of the liquid crystal display device, the liquid crystal display device adopts a direct-type backlight device that does not increase the weight even when the size is increased and that facilitates high brightness. Tend to increase. A liquid crystal display device using a direct-type backlight device is provided with a liquid crystal display panel, a light source that illuminates the liquid crystal display panel from behind, and a light source that is disposed on the opposite side of the liquid crystal display panel, and displays light from the light source on a liquid crystal display. A reflection plate for reflecting light toward the panel is provided. A long fluorescent lamp is mainly used as a light source. In a large-screen liquid crystal device, a plurality of light sources are arranged in parallel at equal intervals, and the light from the plurality of light sources is reflected to the liquid crystal screen as widely and uniformly as possible. For this purpose, the reflector is formed in a shape that is repeatedly bent in accordance with the number of light sources and the distance between the light sources. Conventionally, this type of reflection plate is formed of a synthetic resin vacuum molded product or a reflection layer provided on the surface of a base made of a metal product such as aluminum.

[0003]

However, when a reflector having a shape that is repeatedly bent in accordance with the number of light sources and the distance between the light sources as described above is formed of a vacuum molded product, there is a problem in shape retention. In some cases, local uneven brightness occurs due to deformation. In addition, it is necessary to prepare a mold for the vacuum molded product according to the size, and a clamp margin for clamping the periphery of the sheet is also required for molding, and this clamp margin is cut off after molding and is wasted material. Comes out. Also, when a reflective layer is provided on the surface of a metal base such as aluminum, it is difficult to generate uneven brightness due to deformation due to good shape retention. There is a problem that the induction electricity is generated and the brightness of the fluorescent lamp is reduced by about 20%. The present invention has been made in view of the above-mentioned problems of the related art, and it is an object of the present invention to prevent the occurrence of uneven brightness due to deformation and the like, and to obtain sufficient brightness, and at the time of manufacturing. Another object of the present invention is to provide a reflector which can be manufactured easily and at low cost without wasting material, and which can easily cope with enlargement / reduction of a liquid crystal screen and increase / decrease of light sources.

[0004]

According to a first aspect of the present invention, there is provided a backlight reflector for a liquid crystal display device, wherein a reflective layer is formed on a surface of a substrate which is formed in a repeatedly bent shape. In the formed reflecting plate, the base is made of a synthetic resin molded extrusion.

According to a second aspect of the present invention, there is provided the reflector according to the first aspect, wherein the base is formed of a plurality of profiled extrusions joined and connected in a repetitive bending direction. The joint is located at the center of the valley 32 in the ridge and valley formed alternately on the base by repeated bending.

According to a third aspect of the present invention, there is provided the reflecting plate according to the first or second aspect, wherein the reflecting layer is made of a synthetic resin film processed to increase the reflection efficiency.

[0007] The reflecting plate according to the fourth aspect is the first aspect.
Alternatively, in the reflection plate according to the second aspect, the reflection layer is formed of a paint having high reflection efficiency applied to the surface of the base.

[0008]

According to the reflecting plate of the present invention constructed as described above, since the base is made of an extruded synthetic resin, an induction wave is generated on the base by the electromagnetic waves generated from the fluorescent lamp, and the fluorescent lamp is turned on. The occurrence of inconvenience such as a decrease in the brightness of the image is prevented. In addition, there is no problem with the shape holding surface as in a vacuum-formed product, and local uneven brightness due to deformation is prevented. Further, in the case where the reflection plate has such a repetitively bent shape, the deformed extruded product can be cut into a required length and connected to any size to cope with any size. Therefore, there is no need to prepare a plurality of molds according to the size of the product, and no waste of material is caused. In addition, since each of the deformed extruded products is joined to each other at the center of the valley between the ridges and valleys formed alternately on the substrate due to the repeated bending of the substrate, the extruded products are joined to each other in front of the substrate. Is located at the dead point of the light source arranged at the position.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 illustrates a configuration of a liquid crystal display device using the reflection plate of the present invention.
As shown in the figure, a liquid crystal display panel 1, a light source 2 for illuminating the liquid crystal display panel 1, and a light source 2 disposed on the opposite side of the liquid crystal display panel 1 and transmitting light from the light source 2 to the liquid crystal display panel 1
And a reflecting plate 3 for reflecting light to the side.

The light source 2 comprises a long fluorescent lamp, and a plurality of light sources are arranged in parallel behind the liquid crystal display panel 1 at predetermined intervals. The reflection plate 3 is repeatedly bent at the same pitch to provide the peaks 31 and the valleys 32 alternately, and at least the cross section of the valleys 32 is formed in an arc shape. It is installed so as to be concave toward the light source 2. The pitch of the repetitive bending of the reflection plate 3 is formed so as to coincide with the interval between the light sources 2. The valleys 32 correspond to each light source 2, and the center line of the arc forming the valley 32 is formed. Are installed at a right angle to the axis of the light source 2.

The reflecting plate 3 is formed by providing a reflecting layer 3b on the surface of a base 3a formed in the above-mentioned shape, and the base 3a is made of a synthetic resin, for example, acrylic butadiene styrene (AB).
S), a profile extruded product a such as polypropylene (PP), polyethylene terephthalate (PET) or the like. In the case where the reflector 3 is large and the entire base 3a cannot be constituted by a single extruded molded product a, the base 3a is formed by a plurality of extruded profiles cut to a predetermined length as shown in FIG. The molded article a is connected sideways to form a desired size. In this case, it is desirable that the joint a1 between the profile-extruded products a in the base 3a is located at the center of the valley 32 of the base 3a, and the valley 32 is located immediately behind the axis of the corresponding light source 2. The deformed extruded product a is formed in a shape that can meet such requirements. In addition, profile extrusion molded product a
The ends of the joints should be shaped so that steps or gaps between the adjacent extruded molded products a due to joining are as small as possible. Method should be selected.

The reflective layer 3b is made of a film made of a mixture of polyester, polyethylene or polypropylene and powder of titanium oxide or the like and whitened, or a foamed white polyester film (E-60L manufactured by Toray Industries, Inc.). The entire surface is laminated and bonded via an adhesive (not shown).

The reflection layer 3b is not limited to a tape processed to improve the reflection efficiency, but a paint having a high reflection efficiency can be used in place of the tape. The paint used is a synthetic resin-based white paint mixed with titanium oxide or the like to improve the reflection efficiency.
It is applied in a uniform thin film on the surface.

[0014]

As described above, in the backlight reflector of the liquid crystal display device of the present invention, since the substrate on which the reflection layer is formed on the surface is made of an extruded synthetic resin product, the substrate is made of metal. As in the case of the device, the electromagnetic wave generated from the light source such as the fluorescent lamp does not cause induction electricity to be generated in the base, and the brightness of the fluorescent lamp does not decrease. In addition, there is no problem on the shape holding surface as in a vacuum-formed product, and local uneven brightness is unlikely to occur due to deformation. Therefore, even in a large-screen liquid crystal display device, it is possible to irradiate the liquid crystal panel with reflected light that is sufficiently bright and has no uneven brightness.

[0015] In addition, as for the reflector having a repetitively bent shape like the reflector of the present invention, a high-precision product can be easily manufactured by profile extrusion molding, and material waste such as vacuum molding does not occur. In addition, since it is possible to cut any shaped extruded product to the required length and join it sideways, it is possible to respond to products of any size,
There is no need to prepare multiple molds according to the size of the product.
Therefore, a high quality reflector can be easily obtained at low cost.

Further, by joining the adjacent deformed extruded products to each other at the center position of the valleys in the ridges and valleys formed alternately on the substrate by repetitive bending, the mutually joined deformed extruded products are joined. The connecting portion is located at a dead point with respect to the light source arranged in front of the base corresponding to the valley portion, and by joining the extruded products to each other,
Steps, gaps, and the like that occur between adjacent profile extrusion molded articles do not adversely affect reflection.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a schematic structure of a liquid crystal display device using a backlight reflector of the present invention.

FIG. 2 is a perspective view as viewed from the rear side, showing a base body with a part cut away.

[Explanation of symbols]

 3: Reflector 3a: Base 3b: Reflective layer a: Profiled extruded product a1: Joint between profiled extruded products

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Claims (4)

[Claims] 1. A backlight for a liquid crystal display device, comprising: a reflector having a reflective layer formed on a surface of a substrate formed in a shape that is repeatedly bent, wherein the substrate is made of an extruded product of synthetic resin. reflector. 2. The base is formed by a plurality of profiled extrusions joined and connected in a repetitive bending direction, and joints between the profiled extrusions are alternately formed on the base by repetitive bending. The backlight reflector of the liquid crystal display device according to claim 1, wherein the backlight reflector is located at the center of the valley between the valley and the valley. 3. The backlight reflector of a liquid crystal display device according to claim 1, wherein the reflection layer is made of a synthetic resin film processed to enhance the reflection efficiency. 4. The backlight reflector of a liquid crystal display device according to claim 1, wherein the reflection layer is formed of a paint having a high reflection efficiency applied to the surface of the substrate.