JPS626238B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improvement of a lighting device using a quartz glass fiber, a so-called plastic optical fiber such as an acrylic resin or a polycarbonate resin, or a flat plate made of these materials as a light carrier. In particular, in a lighting device in which a light diffusion layer having a refractive index different from that of the light carrier is provided on the surface of the light carrier, and light is emitted through the light diffuser layer, the light diffuser Provide many layers,
By making these light diffusion layers different in thickness or with different arrangement densities, uniform illumination can be achieved as a whole, and the back surface of the light carrier is made into a reflective mirror surface to improve light utilization efficiency. It is ivy.

Silica glass fibers, plastic optical fibers, thin tubes, flat plates, etc. using these are well known as light carriers, and the applicant has proposed that the refractive index of the light carrier material be determined on the surface of these light carriers. We proposed a lighting device in which light diffusion layers made of, for example, epoxy resin with different refractive indexes are coated and cured, and the light propagated within the light carrier is emitted to the outside through the light diffusion layer for illumination. .

The present invention further improves the above-mentioned illumination device so that uniform illumination can be performed. Specifically, a large number of light diffusion layers as described above are provided, and the thicknesses of these light diffusion layers are made to be different. Alternatively, the arrangement density may be varied to provide uniform illumination as a whole, and the back surface may be a reflective mirror surface to improve light utilization efficiency.

Generally, various types of sign boards and level meters are used in audio equipment and the like, but due to the nature of the product, these require uniform illumination over the entire surface. On the other hand, the power supply voltage to be used must be the secondary side voltage of the transformer (approximately 12 to 24 V), and the light source lamp has restrictions in terms of equipment design, and at the same time, there is no space available. , and the illuminance of the sign board (transmissive type,
No matter which type of reflective type is adopted, it is insufficient and has the inherent defect that average illuminance cannot be obtained. Also, as a light source
Systems that use LEDs are not only insufficient in terms of illuminance, but also require the placement of a large number of LEDs to achieve the desired surface illuminance, which not only complicates wiring but also increases cost. The drawback was that it was expensive.

As another example, various instruments are arranged in the driver's seat of a car, and the speedometer in particular requires an illumination method with an average luminous intensity over the entire surface of the sign board. Figure 1 is a schematic configuration diagram of a conventional automobile speedometer, in which 1 is a light source lamp;
is a reflector, and 3 is a sign board.As is well known, at point A, which is close to light source lamp 1, the distance from reflector 2 is increased, and at point B, which is far from light source lamp 1, the distance from reflector 2 is shortened. In this way, an average uniform illuminance can be obtained. However, this lighting device has an inherent flaw in that the illuminance decreases in areas far away from the light source lamp 1, and there are also complaints that it takes up a certain amount of structural space. It also had drawbacks such as requiring a large number of steps and being unsatisfied with the price.

The present invention has been made in view of the above-mentioned circumstances, and one embodiment thereof is shown in FIG. 2. In FIG. 2, numeral 10 is a light source consisting of a miniature lamp, the light emitting end of an optical fiber, etc., numeral 11 is a light carrier made of quartz glass, acrylic resin, polycarbonate resin, etc., and numeral 12 is provided on the surface of the light carrier 11. The light diffusing layer 12 is composed of a large number of light diffusing layers, and is made of, for example, a two-liquid reaction type epoxy resin or silicone resin, and the refractive index n of the light diffusing layer 12 is the same as that of the light carrier 11.
The refractive index n ₀ is selected so that n ₀ /n=0.87 to 0.95. The light diffusion layer 12 is formed by applying a two-component reactive epoxy resin or silicone resin to the surface of the light carrier 11 and curing it.
Alternatively, the light carrier 11 can be covered with a masking film and formed by spraying, gun blowing, or the like. The light from the light source 10 is introduced into the light carrier 11, and while propagating in the direction of the arrow within the light carrier 11, it is emitted to the outside through the light diffusion layer 12 and is used for illumination. However, in that case, the luminous flux density is high in the part close to the light source 10 and decreases as it moves away from the light source, so the amount of light emitted in the part far from the light source inevitably decreases, making it impossible to achieve uniform illumination. .

The present invention relates to a uniform illumination device that solves the above-mentioned deficiencies, and in the embodiment shown in FIG. In this way, the light source 10
The amount of light attenuation is large in the light diffusion layer near the light source, and the amount of light attenuation in the light diffusion layer decreases as the distance from the light source increases, and as a result, uniform illumination can be obtained. Moreover, in that case, by using the back surface and/or the end surface of the light carrier 11 as a reflecting mirror, the light introduced into the light carrier 11 can be used more effectively.

FIG. 3 is a partially enlarged view showing another example of the light diffusion layer as described above. In this embodiment, the light diffusion layer 12 is configured in the shape of a concave lens, so that the light emitted from the light diffusion layer is It is designed to more effectively diffuse the light. As shown in FIG. 4, this concave lens is made by masking the surface of the light carrier 11 with a masking film 15, and filling the holes 16 of the masking film 15 with a light diffusion layer forming substance 12 such as epoxy resin. When put in with a spray, gun, etc., the light diffusing material 12 will have its surface tension, hole 1
The surface thereof is formed into a concave shape with a curvature determined by the diameter of 6, etc. Therefore, by removing the masking film after the resin has hardened, a concave lens-shaped light diffusion layer can be easily formed.

As is clear from the above description, according to the present invention, it is possible to provide a uniform illumination device that has a simple structure, is mechanically robust, and has high light utilization efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a conventional uniform illumination device, FIG. 2 is a schematic side sectional view showing an example of a uniform illumination device according to the present invention, and FIG. 3 is an example of a light diffusion layer. FIG. 4 is a side sectional view for explaining how to make the concave lens-shaped light diffusion layer shown in FIG. 3. 10...Light source, 11...Light carrier, 12...Light diffusion layer.

Claims (1)

[Claims] 1. Having a large number of discrete light diffusion layers on the surface,
It has a transparent light carrier whose back surface is formed as a reflective mirror surface, and a light source that is disposed on a side surface of the light carrier and introduces light into the light carrier from the side,
In the uniform illumination device, in which the light transmitted through the light carrier is emitted through the light diffusion layer, and the light diffusion layer is configured to provide uniform illumination as a whole, the thickness of the light diffusion layer is A uniform illumination device characterized in that the illumination device becomes thinner as the distance from the light source increases. 2. The uniform illumination device according to claim 1, wherein the light diffusion layer is configured as a concave lens.