JPS62240902A - Optical diffusing body - Google Patents

Abstract

PURPOSE:To permit desired illumination by forming linear Fresnel lens faces extending in the longitudinal direction of a cylindrical body along said body to at least part of the peripheral wall surface of the cylindrical body. CONSTITUTION:This optical diffusing body is constituted of the optically transparent cylindrical body 1 and is formed with the linear Fresnel lens faces 2 extending in the longitudinal direction of the cylindrical body along said body to at least part of the peripheral wall surface of the cylindrical body. An acrylic resin, polycarbonate resin, polystyrene resin or PVC resin, etc., are usable as the material of the cylindrical body 1. The designing of the Fresnel lens faces 2 to have a prescribed luminance distribution by locally providing said faces is also possible in addition to designing the same to have a uniform luminance distribution. The Fresnel lens faces 2 can be provided on not only the outside peripheral wall surface of the cylindrical body 1 but the inside peripheral wall surface or both the faces as well. The light from a ray source is, therefore, controlled and diffused as desired by the linear Fresnel lens faces provided to the cylindrical body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a light diffuser used in lighting equipment, signboards, etc. that incorporates a linear light source such as a fluorescent lamp.

[Conventional technology]

Conventionally, straight tube fluorescent lamps have often been used as light sources for lighting equipment, signboards, etc., and transparent plates with good diffusivity have generally been used for covers and display boards.

An example of this is shown in Figure 6, where transparent plates (A) are arranged on both sides, and a fluorescent lamp (B) is placed in the center of the plate (if multiple fluorescent lamps are used, a large number are arranged in the center of the transparent plate). It was located.

[Problems to be Solved by the Invention] However, with the above configuration, the light No. 1 emitted from the fluorescent lamp (b) is emitted uniformly in the entire circumferential direction, but since it is simply received by a flat surface, there is no light transmission. Not only did the brightness distribution of the vinyl panel become extremely uneven, but also the image of a fluorescent lamp was visible, impairing its functionality and appearance.

To do this, we had to design the fluorescent lamp (b) to be 10 to several tens of cIrL away from the light-transmitting plate (a), but doing so would increase the length of the device in the depth direction ( Therefore, there was a problem that the device could not be made thinner and the weight of the device would also increase.

In view of this situation, the present invention provides light that can illuminate an illuminated object such as a transparent plate with desired regulation even when a linear light source such as a fluorescent lamp is used. The purpose is to provide a diffuser.

[Means for solving problems]

That is, the gist of the present invention is that the main body is composed of an optically transparent cylindrical body and can house a linear light source therein, and that at least a part of the peripheral wall surface of the cylindrical body has a cylindrical shape. The light diffuser is characterized in that a straight Fresnel lens surface is formed along the shaped body and extends in the longitudinal direction.

〔Example〕

The present invention will be described below with reference to drawings of embodiments.

Figure 1 shows the light diffuser of the present invention, in which (1) is a cylindrical body, in this example transparent acrylic resin (refractive index = 1.492) is used, and the diameter is 140 mm. , the thickness of the main body was approximately 5 tm. (2) is a Fresnel lens surface extending in the longitudinal direction provided on the outer peripheral wall surface of this cylindrical body (1), and in this example, lens pieces were formed at 5° intervals from the center of the cylinder.

FIG. 2 shows such a Fresnel lens surface (2), and when designing this, a relationship such as the following equation 0 is derived from Smail's law. Furthermore, X
is the inclination angle of the lens surface of the lens piece, and θ is the angle of the emitted light ray.

rL+ 81nz = le,) sinθ
・e・・・−・・ ■However, ru, = 1.492, ru.

=1.000.

In this embodiment, the illumination cover as shown in Fig. 3 was designed to illuminate uniformly, and this illumination cover has a height of 3.
Two pieces of acrylic resin opalescent board with 60 dragon and 600 silk depth (
C) were assembled at a distance of 160U, and a light diffuser (R) containing a 40W straight tube fluorescent lamp (L) was installed between them.

Figure 4 shows the signature of the light diffuser (R) used at this time. At this time, at the interface between the air layer and the acrylic resin layer, the surface reflection increases as the incident angle increases, so
It is necessary to set the angle with this point in mind.

Turn on the illumination cover as shown in Figure 3 obtained as above and measure the luminance distribution of the opalescent board (using a radiance meter)
As a result, it was found that when the product of the present invention was used, the luminance was almost uniform over the entire height, although the light source was located at a slightly higher location as shown in Figure 5 (2). For comparison, an illumination cover identical to that of the above example except that the light diffuser of the present invention was removed was prepared and measured in the same manner, and the brightness was considerably uneven as shown in Figure 5 (2). An attempt was made to make the luminance of this comparative product similar to that of the inventive product (i.e., as shown in Figure 5), but it turned out that the light source had to be further separated by 120 fi from the opalescent plate, and the lighting cover could not be made thinner. It was confirmed that this cannot be achieved.

The present invention has been described above based on one embodiment.

The present invention is not limited to such examples. For example, as the material for the cylindrical body (1), other than acrylic resin, polycarbonate resin, polystyrene resin, polyvinyl chloride resin, etc. can be used, and the Fresnel lens surface (2) is designed to have a uniform brightness distribution. It is also possible to provide a predetermined luminance distribution by providing the luminance locally instead of a fixed luminance distribution. Furthermore, this Fresnel lens surface (2) may be provided not only on the outer circumferential wall surface of the cylindrical body (1) but also on the inner circumferential wall surface or both.

〔Effect of the invention〕

Since the present invention has the configuration described in detail above, it has a simple structure, but can diffuse light from a linear light source with desired regulation by the linear Fresnel lens surface provided on the cylindrical body. It has the advantage of being able to

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the light diffuser of the present invention.
A) is a plan view, (B) is a front view, FIG. 2 is a partially enlarged view of the linear Fresnel lens surface of the present invention, and FIG. 3 is an example of a lighting fixture using the light diffuser of the present invention. 4 is an enlarged sectional view of part A showing an example of the light diffuser of the present invention;
FIG. 5 is a graph showing the performance of a lighting device using the product of the present invention and a comparative product, and the sixth section is a partial sectional view showing the conventional product. (1)...Cylindrical body (2)...Linear Fresnel lens surface 5'7J L2 book 3z Temporary procedural amendment August 27, 1986 41 Reporter Kuroda Akio-dono, Issue 1, Indication of the case, Patent Application No. 61-85589, 2, Name of the invention, Light diffuser 3, Person making the amendment, Relationship to the case, Patent applicant, 2-3-19 Kyobashi, Chuo-ku, Tokyo (603) Mitsubishi Rayon Co., Ltd. President Akio Kawasaki 4, Representative 2-3-19-7 Kyobashi, Chuo-ku, Tokyo Contents of amendment ftl Figure 4 will be amended as shown in the attached sheet.

Claims (1)

[Claims] It is composed of an optically transparent cylindrical body that can accommodate a linear light source inside, and at least a part of the peripheral wall surface of the cylindrical body has a straight line extending along the cylindrical body and in the longitudinal direction. A light diffuser characterized by having a Fresnel lens surface formed thereon.