JPH1164645A - Flat luminous body - Google Patents

Abstract

(57) Abstract: A light diffusing plate comprising a transparent resin mixed with particles made of a transparent material, and a light source disposed on at least one side of the light diffusing plate, wherein at least one side of the light diffusing plate is provided. In an edge-light type planar light-emitting body in which light incident from the light source is emitted from a light-emitting surface, a large number of V-shaped grooves are formed in parallel on the light-emitting surface of the light diffusion plate and on the back surface opposite to the light-emitting surface. A flat light-emitting body characterized in that: The edge-light type planar light-emitting body of the present invention has a uniform luminance distribution on the light-emitting surface and a high front luminance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge-light type flat illuminant used as a light source for a backlight or a luminous display for a liquid crystal display, a luminous sign, a luminous sign for traffic, and the like.

[0002]

2. Description of the Related Art Conventionally, as a plane light emitter, a fluorescent tube has been conventionally placed under a light diffusion plate.
Further, a so-called direct-type flat light-emitting body (direct-type backlight) in which a reflecting plate or a reflecting sheet is disposed below the fluorescent tube.
There is. However, the direct-type flat illuminant has relatively high brightness but has difficulty in uniformity, and has a large thickness and is not satisfactory in recent years in terms of thinness and compactness.

On the other hand, recently, an edge-light type flat light-emitting body (edge-light type backlight) in which a fluorescent tube is arranged around a light guide plate has been proposed. This edge-light type planar light-emitting body has, for example, a configuration as shown in FIG.

That is, 1 is a light guide plate whose surface (light emitting surface)
A light diffusing sheet 2 and a prism sheet 3 are laminated and disposed on the upper surface, and a reflection sheet 4 is laminated and disposed on the back surface, and a fluorescent lamp (light source) is disposed on at least one side of the light guide plate 1.
5 is arranged. Reference numeral 6 denotes a lamp reflector, which stores these components in a frame 7.

[0005] However, this edge-light type flat illuminant has a low power consumption, a low profile, and a so-called liquid crystal display panel.
Although it satisfies the requirement of compactness to some extent, it is inferior in uniformity of luminance distribution on the light emitting surface. In this case, in order to make the luminance distribution of the light emitting surface uniform, a dot forming method of giving a hemispherical or conical dot pattern or a thin pattern at the time of injection molding instead of dot printing or printing has been adopted. However, in both cases, the pattern is blurred by placing a diffusion sheet on the light emitting surface side, but is not perfect and causes slight luminance unevenness. Further, in order to determine the dot pattern every time the size is changed, it is necessary to test a printing plate or a mold several times, which requires man-hours and costs.

[0006] To solve these problems, there has been proposed an edge-light type planar illuminator using a light diffusing plate formed by mixing particles of a transparent material with a transparent resin as a light guide plate. This method has the advantage that the uniformity of the light emitting surface is controlled by the compounding amount and size of the particles and the shape of the light guide plate, so that the light emitting surface has no unevenness and can be developed at low cost. However, since the emission angle of the emitted light is low, it is necessary to use two prism sheets capable of adjusting the light angle or use a special prism sheet in order to satisfy the luminance in the front direction. There was a problem in terms of cost.

[0007] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide an edge-light type planar light-emitting body which is excellent in uniformity of luminance distribution on a light-emitting surface, has high front luminance, is simple in construction, and can be manufactured at low cost.

[0008]

According to the present invention, there is provided a light diffusing plate comprising a transparent resin and particles made of a transparent material, and a light diffusing plate disposed on at least one side thereof. A light source, and an edge-light-type planar light-emitting body that emits light incident from the light source from at least one side surface of the light diffusion plate from a light-emitting surface, the light-emitting surface of the light diffusion plate and a side opposite to the light-emitting surface. A plurality of V-shaped grooves formed in parallel on the back surface of the light-emitting device, wherein the length direction of each of the V-shaped grooves is 60 ° with respect to the light incident surface of the light diffusion plate. The planar light-emitting device according to claim 1, wherein the flat light-emitting body is formed to have an angle of up to 120 °.
The planar light-emitting device according to claim 1 or 2, wherein the particles made of a transparent material have an average particle diameter of 0.1.
The flat light-emitting body according to claim 1, 2 or 3, which has a thickness of about 50 µm.

That is, the present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a light diffusing plate comprising a transparent resin and particles made of a transparent material is mixed, and a fluorescent tube is formed from at least one side of the light diffusing plate. In the edge-light type planar light-emitting body which receives light according to (1), a continuous and uniform V-shaped groove is arranged on each of the light-emitting surface and the back surface opposite to the light-emitting surface, thereby increasing the front luminance and increasing the prism sheet 1. A planar light-emitting body that achieves the required luminance sufficiently even with a single sheet and does not cause luminance unevenness has been completed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 2, a planar light-emitting body according to the present invention has a fluorescent material on at least one side of a light diffusing plate 11 made of a transparent resin and particles made of a transparent material. A light source 15 such as a lamp is provided.

The particles made of a transparent material used in carrying out the present invention include particles made of an inorganic material such as glass and silicon oxide, fluorine resin, polystyrene resin, acrylic resin, polycarbonate resin, silicone resin, polyethylene resin, and ethylene resin. Particles made of an organic material such as a vinyl acetate resin can be used alone or in combination.

The shape of the particles need not be spherical, and there is no particular limitation on the shape.
It is 1 to 50 μm, more preferably 5 to 20 μm. If the average particle size is outside this range, the light diffusion performance will decrease.

As the transparent resin in which these particles are dispersed to form a light diffusion plate, polystyrene resin, vinyl chloride resin,
Any optically transparent resin such as a polycarbonate resin, a polyethylene terephthalate resin, and an acrylic resin can be used without any particular limitation.

In the present invention, a large number of continuous V-shaped grooves 14 are formed in parallel at a predetermined pitch on the light emitting surface 12 and the back surface opposite to the light emitting surface 12 of the light diffusing plate 11, respectively. In this case, the length direction of these grooves 14 is in the range of 60 ° to 120 °, more preferably 70 ° to 110 °, most preferably 80 ° to 10
It is recommended to form at an angle of 0 ° (that is, along a direction substantially perpendicular to the light incident surface 13).
When the groove is formed near 90 ° in this manner, the light guiding action of the light diffusion plate is not hindered, and uniform light emission and high brightness can be achieved. In the case where the light guide is formed, the light guiding effect is lost, resulting in uneven light emission (only the vicinity of the lamp is bright and the groove is dark).

The size of the V-shaped groove is not particularly limited, but the apex angle α is preferably 45 ° to 135 °, preferably 70 ° to 110 °, more preferably 80 ° to 100 °.
Is good. The pitch d of the V-shaped groove is suitably from 10 to 200 μm in consideration of processing accuracy and quality as a backlight, but is preferably from 20 to 100 μm, and more preferably from 30 to 70 μm (see FIG. 3).

According to the present invention, since a large number of V-shaped grooves are formed as described above, as shown in FIG. 4B, the light is directed in the direction of the light-emitting surface, and as shown in FIG. 4B, when the scattered light in the light scattering plate is emitted, the upper V-shaped The light is refracted on the surface of the groove 14 so that the light is directed in the front direction, and the front luminance is increased.

The other configuration of the flat light-emitting body of the present invention can be a known configuration, for example, the configuration shown in FIG. That is, like the general edge light type flat illuminator, a reflective film on the back surface, a reflective tape on the periphery without a fluorescent lamp, a reflector on the back surface of the fluorescent tube,
On the light emitting surface, a continuous uniform V-shaped groove pattern and a first diffusion sheet for equalizing the distribution of emitted light, a prism sheet for condensing light in the front direction, and further diffusing light as a whole. Components such as a second diffusion sheet that covers small defects and the like and also improves front luminance and a frame that fixes the whole can be provided. What is important here is that two prism sheets have conventionally been used for the purpose of improving the front luminance, but according to the present invention, one or more sheets can achieve the same or higher front luminance.

The light reflection sheet and the reflection tape (reflection material) to be adhered to the back surface or the peripheral portion of the diffusion plate are a light reflection film in which a metal is coated on a transparent film such as polyethylene terephthalate or polycarbonate film, titanium white, carbon charcoal, or the like. A white film for light reflection to which a white pigment such as zinc white and white gloss white CC is added, a white film formed by foaming a transparent material such as polyethylene terephthalate or polycarbonate and the like can be used.

Experimental Example Acrylic resin (refractive index 1.4)
9) 100 parts by weight of silicone resin fine particles (refractive index: 1.
43, an average particle diameter of 12 μm) were mixed and dispersed, and a light scattering plate having a size of 55 mm × 44 mm × 3 mm was prepared by injection molding. A large number of V-shaped grooves were formed in parallel at a pitch of 50 μm. In this case, these grooves were formed along a direction perpendicular to one side surface of the light scattering plate. Then, a fluorescent lamp was disposed on one side of the side surface, and a reflection sheet was laminated on the back surface of the light scattering plate, and a diffusion sheet was laminated on the front surface (light emitting surface). As a result, uniform light emission with high front luminance was obtained.

[0020]

According to the present invention, there is provided an edge-light type flat illuminator,
The luminance distribution on the light emitting surface is uniform and the front luminance is high.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of an edge-light type planar light-emitting body.

FIG. 2 is a perspective view showing one embodiment of the light-scattering plate of the planar light-emitting body of the present invention.

FIG. 3 is an explanatory view of a V-shaped groove.

FIGS. 4A and 4B are explanatory views showing reflection modes of scattered light on a V-shaped groove.

[Explanation of symbols]

 Reference Signs List 1 light guide plate 2 light diffusion sheet 3 prism sheet 4 reflection sheet 5 light source 6 lamp reflector 7 frame 11 light diffusion plate 12 light emitting surface 13 light incident surface 14 continuous V-shaped groove 15 light source L scattered light α apex angle d pitch

Claims (4)

[Claims] 1. A light diffusing plate comprising particles of a transparent material mixed in a transparent resin, and a light source disposed on at least one side of the light diffusing plate, and light is incident on the light diffusing plate from at least one side surface of the light diffusing plate. In the edge light type planar light emitting body configured to emit light from the light emitting surface, a large number of V-shaped grooves are respectively formed in parallel on the light emitting surface of the light diffusing plate and on the back surface opposite to the light emitting surface. Flat luminous body. 2. The flat light-emitting device according to claim 1, wherein the V-shaped grooves are formed so that their respective longitudinal directions are at an angle of 60 ° to 120 ° with respect to the light incident surface of the light diffusion plate. 3. The V-shaped grooves each have an apex angle of 45 ° to 13 °.
The planar light-emitting body according to claim 1, wherein the angle is 5 °. 4. The flat light-emitting device according to claim 1, wherein the particles made of a transparent material have an average particle size of 0.1 to 50 μm.