JPH06174932A - Light transmission plate - Google Patents

Abstract

PURPOSE:To improve the light emitting efficiency of a light emitting surface so as to obtain sufficient brightness, and to restrain transmissibility to be small on the light emitting surface side, so that dot printing in the irregular reflection part of a reflection surface is not viewed from the light emitting surf ace side. CONSTITUTION:This light transmission plate device is provided with a light transmission plate 11 whose one surface is set as the light emitting surface 12 and whose other surface is set as the reflection surface 13, and the irregular reflection part 16 is installed in a dotted state on the reflection surface 13 of the plate 11, then light made incident on the plate 11 is reflected by the reflection surface 13 and also irregularly reflected by the irregular reflection part 16, so that the light is emitted on the light emitting surface 12 side. One light diffusing plate 31 is installed on the light emitting surface 12 of the plate 11 and a lens member 32 having a condensing function is installed on the light diffusing plate 31.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a liquid crystal backlight,
The present invention relates to a light guide plate device used for a backlight for signs such as advertisements and a lighting device.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional light guide plate device disclosed in, for example, Japanese Patent Laid-Open No. 3-264982, one surface of which is a light emitting surface 1.
The light guide plate 3 having the other surface as the reflection surface 2 is provided with the irregular reflection portion 4 formed by dot-printing the ink mixed with the diffusing agent such as silica or titanium oxide on the reflection surface 2 of the light guide plate 3. The light is emitted from the light source 5 through the end face 6 of the light guide plate 3, and the light incident on the light guide plate 3 is reflected by the reflection surface 2 and diffusely reflected by the irregular reflection portion 4 so that the light emission surface 2 side is provided. I try to make it emit light. Then, on the light emitting surface 1 of the light guide plate 3, a light diffusing plate 7 made of a polycarbonate film or the like is used.
Are provided, and the light emitted from the light emitting surface 1 is diffused by the light diffusing plate 7 to make the light emission uniform.

Further, FIG. 8 shows, for example, an actual Kaihei 4--10723.
7 shows another conventional light guide plate device disclosed in No. 7, which includes a light guide plate 3 having one surface as a light emitting surface 1 and the other surface as a reflecting surface 2, and the reflecting surface 2 of the light guiding plate 3 is, for example, silica, Diffuse reflection portions 4 formed by dot-printing an ink mixed with a diffusing agent such as titanium oxide are provided in a dotted pattern, and the light of the light source 5 enters from the end face 6 of the light guide plate 3 and the light incident on the light guide plate 3 is reflected. The light is reflected by the reflecting surface 2 and is diffusely reflected by the irregular reflecting portion 4, and the light emitting surface 2
The side is made to emit light. A lens member 8 having a light-collecting function is provided on the light emitting surface 1 of the light guide plate 3 to improve the brightness of the light emitting surface 1.

[0004]

However, in the conventional case of FIG. 7 in which two light diffusing plates 7 are provided, the light emission from the light emitting surface 1 becomes uniform, but the light emitted from the light emitting surface 1 is diffused. Therefore, as shown by the solid line in FIG. 9, the light largely spreads from the light emitting surface 1 in the direction from the vertical direction to the parallel direction. Therefore, the required light in the vertical direction is reduced, and sufficient luminance cannot be obtained. There was a problem. Further, in the case of the related art shown in FIG. 8 in which the lens member 8 is provided, as shown by the broken line in FIG. 9, the required amount of light in the vertical direction is large and sufficient brightness can be obtained, but the transparency on the light emitting surface 1 side is high. However, there is a problem in that dot printing of the irregular reflection portion 4 of the reflection surface 2 can be seen from the light emitting surface 1 side.

In view of the above problems, the present invention improves the luminous efficiency of the light emitting surface to obtain sufficient brightness, and suppresses the light transmittance of the light emitting surface side so that the light emitting surface side is suppressed to be small. The dot printing and the like of the irregular reflection part of are made invisible.

[0006]

The technical means of the present invention for solving this technical problem comprises a light guide plate 11 having one surface as a light emitting surface 12 and the other surface as a reflecting surface 13. Diffuse reflection portions 16 are provided on the reflection surface 13 of 11 in a scattered manner so that the light incident on the light guide plate 11 is reflected by the reflection surface 13 and is diffusely reflected by the reflection portion 16 so that the light emitting surface 12 side emits light. In the light guide plate device, the light guide plate 11
One light diffusing plate 31 is provided on the light emitting surface 12 and the lens member 32 having a light collecting function is provided on the light diffusing plate 31.

[0007]

Since one light diffusing plate 31 is provided on the light emitting surface 12 of the light guide plate 11 and the lens member 32 having a light collecting function is provided on the light diffusing plate 31, the light diffusing plate 31 is emitted from the light emitting surface 12. The light is appropriately diffused by the single light diffusing plate 31, the transmissivity of the light guide plate 11 is suppressed, the dot printing of the irregular reflection portion 16 is not visible from the light emitting surface 12 side, and the light emission of the light emitting surface 12 is suppressed. Becomes uniform. Moreover, the light emitted from the light emitting surface 12 is not diffused too much, and the light emitted from the light emitting surface 12 as shown by the solid line in FIG.
2 collects light within a range of 45 degrees from the vertical direction of the light emitting surface 12, which increases the required vertical light,
Sufficient brightness can be obtained.

When two light diffusing plates 31 are provided on the light emitting surface 12 of the light guide plate 11 and a lens member 32 having a light collecting function is provided on the two light diffusing plates 31, Since the light emitted from the light emitting surface 12 is diffused too much, the light emitted from the light emitting surface 12 spreads greatly from the vertical direction to the parallel direction as shown by the chain double-dashed line in FIG. The amount of light in the vertical direction decreases, and sufficient brightness cannot be obtained.

The broken line in FIG. 3 indicates the lens member 8
9 is a diagram showing the relationship between the luminance and the emission angle of light in the conventional case of FIG.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In FIG. 1, 11 is a rectangular plate-shaped light guide plate, which is a transparent resin such as acrylic resin, polystyrene, polycarbonate, vinyl chloride, methacrylic resin, or transparent. It is composed of a glass plate or the like. One surface of the light guide plate 11 is a light emitting surface 12
The other surface is the reflecting surface 13. On the reflection surface 13 of the light guide plate 11, a reflection plate 15 made of, for example, a white film of polyethylene terephthalate is provided.
Diffuse reflection portions 16 formed by dot-printing ink mixed with a diffusing agent such as silica or titanium oxide are provided on the reflecting surface 13 of FIG.

Reference numeral 24 denotes a pair of light sources composed of a lamp or the like, which are arranged outside both end surfaces 25 of the light guide plate 11,
Light enters the light guide plate 11 from both end surfaces 25 of the light guide plate 11. Reference numeral 11 denotes a light-shielding cover, which is formed by sticking a silver vapor deposition film on the inner surface of a polyethylene film, for example, so that the light from the light source 24 is not exposed to the outside.
The outer periphery of the light source 24 is covered by the outside of the end surface 25 of the.

On the light emitting surface 12 of the light guide plate 11, a light diffusion plate 31 made of, for example, a polycarbonate film.
Is provided. In addition, a lens member 32 having a light collecting function is provided on the light diffusion plate 31. As shown in FIG. 2, the lens member 32 constitutes a Fresnel lens with a synthetic resin film. 4 and 5 show another embodiment, in which a lens member 32 having a light condensing function is formed by a synthetic resin film having a large number of annular projections 33 formed concentrically on the surface, and the lens member 32 emits light. It is provided on the light diffusion plate 31 on the surface 12. The other points are the same as those of the above-mentioned embodiment.

FIG. 6 shows another embodiment of the present invention, in which a lens member 32 having a condensing function is formed on a surface of which a plurality of linear convex ridges 33 are arranged in parallel so as to be a synthetic resin film (for example, a product of Sumitomo 3M). The name is SOLF). The other points are the same as those of the above-mentioned embodiment. Although the light sources 24 are provided outside the end surface 25 of the light guide plate 11 one by one in the embodiment, instead of this, the end surface 25 of the light guide plate 11 is replaced.
A plurality of light sources 24 may be provided outside.
Further, in the above-mentioned embodiment, the irregular reflection portion 16 is formed by printing the ink mixed with the diffusing agent such as silica or titanium oxide on the reflection surface 13 of the light guide plate 11. However, instead of this, the reflection surface 13 of the light guide plate 11 is changed. The diffuse reflection part 16 is buffed, hairline processed,
It may be formed by strength or weakness such as etching or sandblasting.

[0014]

According to the present invention, the light emitting surface 1 of the light guide plate 11 is formed.
One light diffusion plate 31 is provided on the light diffusion plate 2, and the lens member 32 having a light condensing function is provided on the light diffusion plate 31, so that one light diffusion plate 31 emits light from the light emitting surface 12. Light can be diffused moderately and the transmissivity is suppressed, and the light emitting surface 12
The dot printing of the irregular reflection portion 16 of the reflecting surface 13 can be made invisible from the side, and the light emission of the light emitting surface 12 becomes uniform. Moreover, the light emitted from the light emitting surface 12 is not diffused too much, and the light in the vertical direction required by the condensing function of the lens member 32 is increased, so that sufficient brightness can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a condenser lens showing an embodiment of the present invention.

FIG. 3 is a graph showing a relationship between a light emitting direction of a light emitting surface and brightness.

FIG. 4 is a plan view of a condenser lens showing another embodiment.

FIG. 5 is an enlarged cross-sectional view of a condenser lens showing another embodiment.

FIG. 6 is a plan view of a condenser lens showing another embodiment.

FIG. 7 is a side sectional view showing a conventional example.

FIG. 8 is a side sectional view showing another conventional example.

FIG. 9 is a graph showing a relationship between a light emitting direction of a light emitting surface and brightness.

[Explanation of symbols]

 11 Light guide plate 12 Light emitting surface 13 Reflecting surface 16 Diffuse reflecting part 24 Light source 31 Light diffusing plate 32 Lens member

Claims (1)

[Claims] 1. A light emitting surface 12 on one side and a reflecting surface 1 on the other side.
The light guide plate 11 having the number 3 is provided, and the reflecting surface 13 of the light guide plate 11 is provided.
Further, the irregular reflection portions 16 are provided in a scattered manner so that the light incident on the light guide plate 11 is reflected by the reflection surface 13 and the irregular reflection portion 1
In the light guide plate device in which light is diffusely reflected by 6 to emit light on the side of the light emitting surface 12, one light diffusion plate 31 is provided on the light emitting surface 12 of the light guide plate 11, and the light condensing function is provided on the light diffusion plate 31. Lens member 3 having
2. A light guide plate device, which is provided with 2.