JPH01904A - backlight device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a backlight device useful as a display in industrial and office equipment, a display device using liquid crystal, and the like.

(Prior art and its problems) As shown in Fig. 4, a conventional backlight device for liquid crystal or display displays includes a light diffusion filter b such as white frosted glass or white plastic sheet below the liquid crystal or display a. A concave reflecting mirror C is provided through the
In some cases, a cold cathode tube d is placed in the center of the display, or as shown in FIG.
A device in which plane reflecting mirrors e are sequentially provided is known.

However, in the former device, only the central part of the liquid crystal is particularly bright and the peripheral part is dark, so in order to brighten the entire area, the concave part of the concave reflector C must be deepened to increase the focal length, and as a result, There is a drawback that the entire device becomes thicker, and since the latter device uses a large number of light sources, there are problems in that it consumes a lot of power and easily generates heat.

(Means for Solving the Problems) The present invention was achieved by focusing on the fact that these problems can be easily solved by using a fine interdigital sheet as a reflective type backlight device. The gist of this invention is that a fine interdigital sheet in which layers are alternately laminated and integrated in parallel is disposed between a liquid crystal or display and a light source.

Hereinafter, details of the present invention will be explained based on the embodiments shown in FIGS. 1 to 3. The backlight device shown in FIG. A cold cathode tube 5 is placed on the side as a light source, and a liquid crystal 6 is placed directly above this device. In this device, the light from the light source is uniformly diffused without attenuation, and the entire liquid crystal is uniformly irradiated, so there is an advantage that only one light source is required.

FIG. 2 shows a similar device in which a display 7 is placed above the liquid crystal 6, and all of the light from the light source is reflected and diffused to illuminate the display 7.

Examining this in more detail based on FIG. 3, the fine interdigital sheet 3 used here has a thickness of 12.5 mm as the reflective layer 1. The surface of the transparent polyethylene phthalate has a thickness of 4
Transparent M
2 is made of transparent silicone rubber with a thickness of 150p, the thickness of the sheet is 3001 and the refractive index is 1.58, and the one shown in FIG. When the angle of the line connecting the center with the cold cathode tube 5 to the sheet surface is 8a, in this case the slope of the laminated surface is 1
If it is 9°4@, all the light will exit to the upper side of the sheet 3. Similarly, Figure (B) shows the case where the above angle is 22 degrees, in which case the slope of the laminated plane is 18'', and Figure (Q) shows when the angle is 573, the slope of the laminated plane is 10''.
@ indicates that it is OK.

The material forming the transparent layer 2 in the fine interdigital sheet 3 is made of transparent plastic, rubber, an alloy thereof, or a mixture thereof, and includes, for example, thermoplastic polyvinyl chloride, polystyrene, Polyamide (nylon), polybutyral, polyacetyl butyral, cellulose resin, polycarbonate, polyester, polysulfone, polyethylene, polypropylene, poly-4-ethylenepentene-1, polyvinyl acetate, polymethyl methacrylate, other plastic alloys, etc. Thermosetting epoxy resin.

Examples include polyurethane, silicone rubber, melamine resin, polyester resin, as well as air and glass.

In addition, the material forming the reflective layer 1 may be one obtained by coating the surface of the material forming the transparent layer 2 with a metal film or foil made of aluminum, tin, etc., a white pigment such as titanium oxide, or a material such as glass beads. Examples include sheets in which retroreflective materials are uniformly dispersed in plastic.

The fine interdigital sheet 3 is made by laminating the transparent layer-forming material and the reflective layer-forming material described above alternately and in parallel in multiple layers at a lamination pitch of 30 to 200-200, and then forming the obtained laminated block body. , can be obtained by slicing at any angle across the laminated surface.

When forming this laminated block, heating and pressurizing are sufficient when the transparent layer and reflective layer forming materials are respectively made of self-adhesive plastic or silicone rubber, but if other materials are used, the adhesive strength may be insufficient. When doing so, they may be laminated and integrated using adhesive or adhesive.

The adhesive used here is a reaction-curing adhesive or a dry-setting adhesive, such as a urethane adhesive, an epoxy adhesive, a vinyl chloride-vinyl acetate adhesive, a rubber adhesive, and the like.

On the other hand, since the sliced sheet has an optically matte cut surface, one or both sides of the sheet may be coated with the above-mentioned transparent plastic, rubber, an alloy thereof, a mixture thereof, or an inorganic or organic material. The range and directivity of reflection can be changed by attaching a piece of glass, or by changing the thickness of the slice and its angle.

(Effects of the Invention) According to the backlight device according to the present invention, (1) a liquid crystal display device can be made thin;

■Energy can be saved when using LCD.

■The difference in brightness and darkness of the display device becomes smaller and becomes clearer.

Since the characteristics as a display device are improved, its industrial value is extremely large.

[Brief explanation of drawings]

1 to 3 relate to embodiments of the present invention, and FIGS. 1 and 2 are explanatory diagrams of backlight devices of different embodiments, respectively, and FIGS. 3(a), (b), (
c) is an explanatory diagram showing the relationship between the inclination angle of the laminated surface of the fine interdigital sheet and the position of the light source in backlight devices of different embodiments, and FIGS. 4 and 5 are diagrams of conventional examples of different embodiments, respectively. It is an explanatory diagram. (Explanation of main symbols) 1... Reflective layer, 2... Transparent layer, 3...
...Fine blind-like sheet, 5...Light source, 6
...LCD, 7...Display. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A backlight device in which a fine interdigital sheet in which reflective layers and transparent layers are alternately laminated and integrated in parallel is disposed between a liquid crystal or display and a light source.