JPS61246702A - light diffuser - Google Patents

Abstract

PURPOSE:To make possible the obtaining of uniform plane illumination by combining plural pieces of optical transmission means constituted of plural transparent plate-shaped bodies. CONSTITUTION:The optical transmission means 1 is constituted by laminating the plural transparent plate-shaped bodies having different lengths and forming the same in such a manner that the sectional shape thereof is like a wedge. A long-sized light source L such as fluorescent lamp is disposed along a light incident end 2 of such means 1, then the incident light on the individual transparent plate-shaped bodies constituting the means 1 from the incident end 2 advances between the transparent plate-shaped bodies in the arrow direction and is emitted from a light exit end 3. The light parallel with the transparent plate-shaped bodies advanced rectilinearly and the light inclined with the transparent plate-shaped bodies arrives at the end 3 by repeating reflections in the transparent plate-shaped bodies. Two pieces of such means 1 are combined in such a manner that the wedge-shaped top ends are adjacent to each other and that the exit ends 3 are positioned on the same plane, by which the approximately uniform plane illumination with a large area is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light diffuser that is most suitable for use as a surface illumination device. More particularly, the present invention relates to edge lighting type light diffusers.

[Conventional technology]

Conventionally, large surface lighting devices have been used as signboards and various display devices, and small surface lighting devices have been used as display devices for various devices and liquid crystal watches. In signboards and large display devices, it has been common practice to arrange a large number of fluorescent lamps, which are linear light sources, and incandescent lamps, which are point light sources, on the back side of a light diffusion plate to illuminate the surface to be illuminated. However, in such a surface illumination device, in order to obtain surface illumination with uniform brightness, it is necessary to increase the distance between the light diffusion plate and the light source considerably, or to arrange a large number of light sources close to each other. It was necessary.

As a result, the surface illumination device becomes large, and the increase in the number of light sources not only increases the price of the surface illumination device, but also increases power consumption.

In order to correct these drawbacks, it has been put into practical use in some cases to use a single transparent light guide plate and guide light from the negative end thereof, thereby obtaining area illumination. When such a transparent light guide plate is used, if the incident light from the light source is parallel rays, it is possible to obtain surface illumination with fairly uniform brightness. However, the light from the light source actually spreads radially, so the amount of light emitted from the transparent light guide plate is large near the light source, and the amount of light emitted from the light guide plate is small at a position away from the light source. For this reason, it has been difficult to obtain uniform surface illumination using conventional techniques.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a light diffuser that can provide uniform area illumination. Another object of the present invention is to provide a light diffuser that is easy to manufacture and can provide high brightness and uniform surface illumination. A further object of the present invention is to provide a light diffusing plate that can be used for signboards, large display devices, equipment display devices, liquid crystal display devices, and the like.

Still other objects of the present invention will become apparent from the following description.

[Means for solving problems]

An object of the present invention is to provide a light diffuser of the edge lighting type that is provided with a light incidence surface, a light transmission means, and a light exit surface, in which a plurality of light transmission means are laminated. This is achieved by using a plurality of such optical transmission means.

The present invention will be explained below with reference to FIGS. 1 to 7.

FIGS. 1(a) to 1(d) are cross-sectional views of embodiments of the light diffuser of the present invention.

The light diffuser shown in Figs. 1 (al to d) consists of two light transmission means (1) constructed by laminating a plurality of transparent plate-like bodies of different lengths so that the cross-sectional shape is wedge-shaped. The wedge-shaped tips are adjacent to each other and are combined so that the light-emitting ends are on the same plane.

The light output end (3) of the light transmission means in the embodiment shown in FIG. Both are inclined with respect to the expanding surface of the transparent plate-like body. Further, the area of the light output end (3) is sufficiently larger than the area of the light input end.

If a long light source (L) such as a fluorescent lamp is placed along the light incidence end (2) of such a light diffusion means (1), the light diffusion means (1) will be constructed from the light incidence end). The light incident on each transparent plate-like body travels between the transparent plate-like bodies in the direction of the arrow in FIG. Light that is parallel to the transparent plate travels straight, and light that is inclined with respect to the transparent plate is repeatedly reflected within the transparent plate and reaches the light emitting end (3).

By combining two such optical transmission means+11 so that their wedge-shaped tips are adjacent and their light emitting ends are on the same plane as shown in FIG. 1(a), a large-area and approximately uniform You can get surface lighting.

The transparent plate may be made of methyl methacrylate polymer and have a thickness of 0.2 wm, 0.5 sm, 1.0 or 2.0 mm, for example. A plate-like body of OIm was used. Note that the same transparent plate-like body was used in the following examples as well.

In the embodiment shown in FIG. 1(b), the light emitting end (3) of the light transmitting means (1') has a stepped shape, and a prism-like light diffusing plate (4) is further covered thereon. The light incident on the light input end (at the light input end) propagates through the transparent plate forming the light transmission means (1') and exits from the light output end (3). Furthermore, the light emitted from the light emitting end is passed through a prismatic light diffusing plate (4).
After being reflected or refracted, the light is emitted from the prismatic light diffusing plate (4), resulting in approximately uniform surface illumination.

By combining two such optical transmission means (1') so that their generally wedge-shaped tips are adjacent to each other as shown in Figure 1(b) and their light output ends are approximately on the same plane, a large area can be obtained. Moreover, substantially uniform surface illumination can be obtained.

The prismatic light diffusing plate is made of transparent methacrylic resin or polycarbonate resin by extrusion molding.
A plate formed so that a large number of protrusions having an equilateral triangular cross-sectional shape, extending at right angles to the direction in which the plate-shaped bodies are arranged (perpendicular to the plane of the paper), are provided at equal intervals is used. .

Note that the same prismatic light diffusing plate was used in the following examples as well.

In the embodiment shown in FIG. 1(e), the light transmitting means (one light emitting end (3) is a continuous inclined surface, and in contact with this light emitting end (3), a light reflector (5) It is configured by providing.

The light incident on the light input end (2) propagates through the transparent plate-like body constituting the light transmission means and reaches the light output end. This light is reflected in the reflection direction by the light reflector (51),
The upper part of FIG. 1(e) is illuminated.

By combining two such optical transmission means (1') so that their wedge-shaped tips are adjacent to each other and their light output ends are on the same plane as shown in Figure 1(c), a large area can be obtained. Moreover, substantially uniform surface illumination can be obtained.

As the light reflector (5), for example, 100 having a mirror surface is used.
ltm thick polyester A! The light emitting end (3) was formed by attaching a vapor-deposited film to the light emitting end (3) or by directly applying a metal vapor deposited film such as AJ or AJI to the light emitting end (3). Note that the same transparent plate-like body was used in the following examples as well.

In the embodiment shown in FIG. 1(d), the light emitting end (3) of the light transmission means (1'') is stepped, and the other structure is substantially the same as that of the embodiment shown in FIG. 1(c). is the same as

Two such optical transmission means (1") are arranged, as shown in FIG.
By combining them so that they are on the same plane, it is possible to obtain substantially uniform area illumination over a large area.

FIGS. 2(a) to 2(d) are cross-sectional views of other embodiments of the light diffuser of the present invention.

The light diffuser in Fig. 2 has a light transmitting means (1) constructed by laminating a plurality of transparent plate-like bodies of different lengths so that the cross-sectional shape is wedge-shaped, as in Fig. 1. 2' pieces, wedge-shaped tips facing opposite directions on both sides of one light source, combined so that the light output ends of the two light transmission means (1) are on the same plane. It is.

FIG. 2(a) shows a combination of two light transmission means (1) each having a light emitting end formed of a continuous inclined surface.

In addition, in Fig. 2(b), the light output end (3) has a step-like shape, and two light transmission means (1') configured by covering a prism-shaped light diffusing plate on top of it are combined. It is something that

Furthermore, FIG. 2(c) shows a combination of two light transmission means (1') each having a light emitting end consisting of a continuous inclined surface and a light reflector provided in contact with the light emitting end. It is.

Furthermore, Fig. 2 (dl) is a combination of two optical transmission means (1'') each having a step-like light emitting end and a light reflector provided in contact with the light emitting end. be.

By combining the trap light transmission means as described above, it is possible to efficiently obtain substantially uniform surface illumination over a large area.

FIG. 3 is a cross-sectional view of another embodiment of the light diffuser of the present invention.

The light diffuser in Fig. 3 includes a light transmission means (1) constructed by laminating a plurality of transparent plate-like bodies of different lengths so that the cross-sectional shape is wedge-shaped, as in Fig. 1. Two pieces are stacked one on top of the other so that the light emitting ends (3) are parallel and the wedge-shaped tips are facing in opposite directions.

Figure 3 (al) shows two light transmitting means (1) whose light emitting ends are made of continuous inclined surfaces stacked one on top of the other so that the light emitting ends are parallel to each other. Since the light emitting ends are oriented upward and downward, a light diffuser capable of illuminating the front and back sides simultaneously can be obtained.

In addition, in FIG. 3(b), the light emitting end is stepped,
Furthermore, a light transmitting means (1') consisting of a prism-shaped light diffusing plate is placed on top of it so that the light emitting ends are parallel to each other.
It is a stack of pieces.

Further, FIG. 3(c) shows a light transmitting means (1') having a light emitting end consisting of a continuous inclined surface and a light reflector (5) provided in contact with the light emitting end. Two pieces are stacked so that the ends (3) face each other in parallel with a light reflecting plate in between.

Furthermore, FIG. 3(d) shows that the light emitting end is stepped, and in contact with the light emitting end, two light transmitting means (1") each having a light reflector (5) are provided. , the light emitting ends are superimposed on J-5, which are parallel to each other with a light reflecting plate in between.

By combining the light transmission means as described above, it is possible to simultaneously illuminate the front and back sides, and to obtain approximately uniform surface illumination.

FIGS. 4(a) to 4(d) are cross-sectional views of other embodiments of the light diffuser of the present invention.

The light diffuser in FIG. 4 includes a light transmission means (1) constructed by laminating a plurality of transparent plate-like bodies of different lengths so that the cross-sectional shape is wedge-shaped, as in FIG. 1. Two wedge-shaped tips are stacked one on top of the other with their ends pointing in the same direction.

FIG. 4(a) shows the light transmitting means (1) whose light emitting ends are continuous inclined surfaces, with their wedge-shaped ends facing in the same direction, and their light emitting ends (3) facing in opposite directions. It is two pieces stacked on top of each other. As shown in the figure, since the two light emitting ends are oriented substantially in the vertical direction, a light diffuser capable of simultaneously illuminating the front and back sides can be obtained.

Also, in Figure 4 (bl), the light emitting end is stepped,
Furthermore, two light transmitting means (1') which cover a prism-shaped light diffusing plate are stacked on top of the light transmitting means (1') so that their wedge-shaped tips face in the same direction.

Furthermore, FIG. 4 (cl) shows a wedge-shaped light transmitting means (1') having a light emitting end consisting of a continuous inclined surface and a light reflector (5) provided in contact with the light emitting end. It consists of two sandwiched light reflecting plates (5) stacked one on top of the other so that their tips face in the same direction.

Furthermore, FIG. 4(d) shows that the light emitting end is stepped, and a light transmitting means (1") constituted by providing a light reflector (5) in contact with the light emitting end is wedged. Two pieces are stacked together with a light reflecting plate (5) in between so that the tips of the shapes face in the same direction.

By combining the light transmission means as described above, it is possible to simultaneously illuminate the front and back sides, and to obtain approximately uniform surface illumination.

FIGS. 5(a) to 5(d) show other embodiments of the light diffuser of the present invention.

The light diffuser in FIG. 5 is similar to the light emitting end (3) of the light diffuser in FIG.
), a light diffusing plate (6) is further placed on top of the light diffusing plate (6). The light diffusing plate (6) may be provided in contact with the light emitting end or the prismatic light diffusing plate, or may be provided at an appropriate interval.By providing this light diffusing plate, the light diffusion plate (6) can be provided evenly. Good surface illumination can be obtained at once.

Similarly, in addition to the embodiment shown in FIG. 1, in the embodiments shown in FIGS. 2 to 4, a light diffuser can be constructed by combining light diffusing plates, and similar effects can be obtained.

FIG. 6 is a perspective view of another embodiment of the light diffuser of the present invention. This is a combination of four optical transmission means shown in FIG. 1(c). One optical transmission means has a generally wedge-shaped cross section and a triangular shape in the spreading direction. FIG. 7 is a cross-sectional view of the light diffuser of FIG. 6.

In this way, the light diffuser of the present invention is not limited to the combination of only two optical transmission means, but may be configured using two or more or a plurality of optical transmission means. Thereby, it is possible to obtain substantially uniform surface illumination over a larger area.

Furthermore, the optical transmission means may be combined not only by combining the same type of optical transmission means, but also by combining different types of optical transmission means.

〔Effect of the invention〕

As described above, the light diffuser according to the present invention is formed by combining a plurality of light transmission means each composed of a plurality of transparent plate-like bodies.

Therefore, by using the transparent plate-like body as a light guide, it is possible to guide the light incident from the light input end to the output end remote from the light source, thereby obtaining uniform illumination with less spots.

[Brief explanation of the drawing]

Figures 1 to 5 are cross-sectional views of embodiments of the light diffuser of the present invention, and are explanatory diagrams when two optical transmission means are combined, and Figures 6 and 7 are cross-sectional views of an embodiment of the optical diffuser of the present invention. FIG. 3 is a perspective view and a cross-sectional view of an embodiment of a combined light diffuser. (x)* (t')* (x')* (1...
Light transmission means (2)...Light incidence end (3)...Light output end (4)...Prismatic light diffusion plate (5)...Light reflection plate ( 6)...Light diffusion plate tl-1 A 1221 Fig. 2 Fig. 3 Nichiryo 4 Fig. 6

Claims (1)

[Claims] A light diffuser of the type that illuminates the end face and is equipped with a light incident surface, a light transmission means, and a light output surface, in which the light transmission means is composed of a plurality of laminated transparent plate-like bodies, and A light diffuser characterized by using a plurality of light transmission means.