JPH05224614A - Plane light source device - Google Patents

Abstract

PURPOSE:To provide a plane light source device which is made thin without generating a bright line and without lowering brightness. CONSTITUTION:A reflecting plate 4 having curved surfaces respectively corresponding to plural fluorescent lamps 3 arrayed in parallel is incorporated in a box type housing 2, an acrylic transparent plate 5 is provided on the front surface, and a diffusion film 1 is disposed on the inner surface of the plate 5. White paint is applied to the back part 6 of the fluorescent lamp on the reflection plate J4 and the connection part 6 of the respective curved surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat light source device,
In particular, the present invention relates to a flat light source device suitable for thin and lightweight advertising signs, display devices, flat lighting devices, and the like.

[0002]

2. Description of the Related Art As a conventional flat light source device used for advertising billboards, display devices, flat lighting devices, etc., a linear light source such as a plurality of fluorescent lamps is installed in a housing, and
A structure in which a diffusion plate such as an acrylic milk half plate is arranged at a considerable distance from the fluorescent lamp is mainly used. Although these flat light source devices are used for illuminated signboards and various display devices, in recent years, in particular, there is a strong demand for lighter and thinner devices as the overall size increases.

[0003]

However, when a linear light source such as a fluorescent lamp is brought close to the illuminating surface in order to reduce the thickness, a bright line appears, and in order to eliminate such a bright line, a blocking member or a thick diffusion layer is used. When the plate is used, the brightness as a whole is lowered, the utilization efficiency of the light quantity is lowered, and the weight is increased.

In the flat light source device as shown in FIG. 1, the present inventors reduced the brightness when a diffusion film in which a titanium pigment-containing polyvinyl chloride resin was laminated and impregnated on a polyester cloth was used as the diffusion sheet. It was confirmed that the device can be made thin without doing so. However, even in this case, the prevention of the generation of bright lines was not completely satisfactory.

The present invention has been made on the basis of the above background, and an object thereof is to provide a flat light source device which can be made thin without generation of bright lines and without lowering brightness. It is in.

[0006]

The present inventor has completed the present invention as a result of intensive studies in view of the above situation.

That is, the gist of the present invention is a flat light source device in which a plurality of linear light sources are arranged in parallel and built in, a reflecting surface is provided on the back surface of the light source, and a diffusion sheet is provided on the front surface. The reflecting surface is composed of a plurality of curved surfaces corresponding to the light source, and the reflecting surface of a portion corresponding to the rear portion of the linear light source and the reflecting surface of each connecting portion of the plurality of curved surfaces are painted white. The flat light source device is characterized in that

The flat light source device of the present invention can be made thin by using a specific reflecting surface, and no bright line is generated.

The reflecting surface of the flat light source device of the present invention has curved surfaces corresponding to a plurality of linear light sources, respectively.
Further, the reflection surface of the portion corresponding to the rear part of the linear light source and the reflection surface of the connecting portion of each of the plurality of curved surfaces must be painted in white. The shape of the curved surface of the reflecting surface is appropriately determined according to the characteristics of the linear light source and the width of the white coated portion. Similarly, the width of the white painted portion is appropriately determined depending on the shape of the reflecting surface and the characteristics of the linear light source. The reflecting surface is preferably a mirror surface on which a metal such as silver or aluminum is deposited.

[0010]

EXAMPLES The present invention will be described in detail below with reference to examples. A sectional view of an example of the flat light source device of the present invention is shown in FIG. 2, and a sectional view is shown in FIG. In this example, the plurality of fluorescent lamps 3 arranged in parallel to the box-shaped housing 2 and the rear surface of the fluorescent lamp 3 are
A reflecting plate 4 having a curved surface corresponding to each fluorescent lamp is built in, an acrylic transparent plate 5 is provided on the forefront, and a diffusion film 1 is provided on the inner surface thereof. It should be noted that the rear portion 6 of the fluorescent lamp of the reflector 4 and the connecting portion 6 of each curved surface are painted white. Further, comparative evaluation with the present invention was carried out by using a reflection plate having no white coating. As a result, while the bright line is generated in the comparative example, no bright line is generated in the example of the present application,
The brightness was also satisfactory.

[0011]

As is apparent from the above description, the flat light source device according to the present invention can be made thin without the generation of bright lines and without lowering the brightness. It is suitable for signboards, display devices, flat lighting devices, and the like.

[Brief description of drawings]

FIG. 1 is a conventional flat light source device.

FIG. 2 is a cross-sectional external view of a flat light source device that is an example of the present invention.

FIG. 3 is a cross-sectional view of a flat light source device that is an example of the present invention.

[Explanation of symbols]

 1 Diffusion film 2 Housing 3 Fluorescent lamp 4 Reflector 5 Acrylic transparent plate 6 White coating part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // F21V 7/22 G 2113-3K 13/10 2113-3K

Claims (1)

[Claims] 1. A flat light source device in which a plurality of linear light sources are arranged in parallel and built-in, a reflecting surface is provided on the back surface of the light source, and a diffusion sheet is provided on the front surface thereof, wherein the reflecting surface is the A flat light source device comprising a plurality of curved surfaces corresponding to a light source, wherein a reflecting surface of a portion corresponding to a rear portion of the linear light source and a reflecting surface of each connecting portion of the plurality of curved surfaces are white-painted. ..