JPS59147387A - Plane diffuser - 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 The present invention relates to a flat diffuser used as a surface illumination device, and aims to provide a device that is simple in construction, lightweight, and inexpensively available.

As surface lighting devices, large ones are widely used for signs and various display devices, and small ones are widely used as display devices for equipment and liquid crystal clocks. Among these area lighting devices, for large signboards and display devices, it is common to use a large number of fluorescent lamps, which are linear light sources, or incandescent lamps, which are point light sources, to illuminate the back of the light diffusion plate. Met. However, in order to maintain uniform brightness in such a surface lighting device, it is necessary to increase the distance between the light diffuser plate and the light source, or to arrange a large number of light sources closely.
The problem is that the device becomes larger and the number of light sources increases, which increases the price and increases power consumption.

In order to improve this point, some proposals have been made to use a transparent light guide plate to guide light through the side edges and thereby diffuse illumination of the surface. This has already been accomplished in Japanese Patent Publication No. 51-88042, and has been put into practical use in some cases. By the way, when using a transparent light guide plate in such a device, although it is possible to make the device thinner than the above-mentioned surface illumination device ff1i', the thickness of the transparent light guide plate is determined by the thickness of the transparent light guide plate. Therefore, it is not possible to make the transparent light guide plate thinner than 9 mm, and for use in medium-sized or larger display devices, it becomes bulky and the amount of phase used for the transparent light guide plate increases. In addition, this transparent light guide plate has a hairline-like rough surface on the back side, which makes it difficult to finish, and in particular, there is a loss of absorption of light in order to guide light inside the transparent light guide plate, and the light source used There was a problem in that the capacity had to be made larger than necessary.

The unexploded BJ-1 was created in light of this situation, and its gist is as follows:
It is equipped with an introductory part 'f' on the front, a light scattering part 'f on the back, and a light scattering part 'f on the back.
The front diffuser is characterized in that a space 111 is provided between the front diffuser and the light scattering/reflecting section.

Hereinafter, the present invention will be explained in detail according to drawings of embodiments.

In the figure, (1) is the light introduction part of the (1111 plane), and in the example in the figure, the shorter opposing side is the introduction part (1), but of course this introduction part (1) is - The introduction part (1) may be made of a transparent acrylic resin column with a thickness of 8 mm, for example, and one side faces the light source (Ll), and the other side faces the light source (Ll). A space where the surface of power describes a bale (81
It is oriented toward In addition, (2) in the figure is the diffused light transmitting part (2) on the front, and this diffused light transmitting part (2) is equipped with f6
It is located all over the area.

In the illustrated example, an acrylic impact-resistant sheet material (c) is laminated on the top surface of a transparent acrylic resin with a thickness of 0.8 van. The sheet-like material (c) (for example, the 250μ thick Mitsubishi Rayon "Hypet" sheet) has a high degree of light diffusion performance, so it has good diffusion holes (2). .

Furthermore, (3) in the figure is a light scattering and reflecting part located on the back side, and in the illustrated example, the height is 450 μm on the top surface of the retroreflective sheet 01).
[Acrylic surface] A wandering sheet-like material is laminated. In addition, (4) in the figure is the back plate further back of the light scattering reflection part (3), and (5) is the outer surface of this back plate (4) and the outer surface of the side other than the light introduction part (1). In the covering reflective sheet, p and (s) are spaces provided between the diffused light transmitting section (2) and the light scattering/reflecting section (3).

Since the present invention is as described above, when the light source (L) is turned on and used, the light is transmitted from the introduction part (1) to the space part (s).
incident on l. This incident light propagates while scattering or going straight through the space (Sli), but part of the light passes directly through the diffused light transmitting part (2), and the light in the -' part passes through the diffused light transmitting part (2) as shown in Figure 6. After being scattered and reflected by the light scattering and reflection (3), the light is transmitted through the diffused light transmission section (2).Therefore, the light guided to the light source (L) is uniformly diffused, and this diffused light transmission The transmissive liquid crystal or translucent sheet provided in contact with the portion (2) illuminates uniformly.

In the illustrated example, the light introduction portions (1) are provided on opposite sides, but of course, the light guide portions (1) may be provided only at -10,000. In addition, in this example, the space (S) becomes narrower as it moves away from the light introduction part (1), which means that the scattered reflection by the light scattering part (3) as shown in FIG. ) to compensate for the loss of light quantity.

Since the present invention has the structure as described in detail above, the light incident from the introduction part is scattered or goes straight into the space surrounded by the diffuse light transmitting part and the light scattering reflection part, and the light that enters the space surrounded by the diffuse light transmitting part and the light scattering reflection part is scattered or goes straight. Since uniform light is emitted from the light part, it is possible to provide a flat diffuser used in a surface illumination device, and has the advantage of having a simple structure, a small amount of t, and being easily available.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
FIG. 3 is an enlarged sectional view of the second drawing portion. (1)...Light introduction part (2)...Diffusion light transmission part (3)...Light scattering reflection part (5)...Reflection sheet (S) ...Space Department Patent Applicant Mitsubishi Rayon Co., Ltd.

Claims (1)

[Claims] 1. A light introduction part is provided on the side surface, a diffused light transmitting part is provided on the front side, and a full scattering reflective part is provided on the back side, and the diffused light transmitting part and the light scattering reflective part are provided. A flat diffuser characterized in that a space is provided between the diffusers. 2. A planar diffuser according to claim 1, wherein the space between the light-diffusing and light-transmitting portion and the light-scattering and reflecting portion becomes narrower as the distance from the light introduction portion increases. 5. The planar diffuser according to claim 1 or 2, characterized in that the outer surface of the light scattering and reflecting portion and the outer surface of the side surface that is not the light introducing portion are covered with a reflective sheet.