JPS6323109A - Sunlight collecting device - Google Patents

Abstract

PURPOSE:To improve the effect of leading sunlight to a light transmitting cable so as to collect sunlight, by making the light emitting end side numerical aperture of a coupling coincident with the numerical aperture of the cable and the numerical aperture of a lens with the light leading-in end side numerical aperture of the coupling. CONSTITUTION:A lens whose numerical aperture is small, namely, whose peripheral section has a rising angle which is not large is used as the condenser lens 1 of this sunlight collecting device. Therefore, reflection in the peripheral section of this lens 1 is small and sunlight can be converged efficiently with the lens 1. The light beams led into an optical coupling 3 advance toward a light transmitting cable 2 while it is reflected by the inner wall surface of the optical surface, but its angular aperture becomes larger as it is reflected by the wall surface. Therefore, if the angular aperture of the light beams emitted from the light emitting end 3b of the optical coupling 3 is made coincident with that of the light transmitting cable 2, the light beams can be led efficiently into the optical cable 2 from the optical coupling 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sunlight collecting device that effectively introduces sunlight focused by a lens into a light conductor cable.

Figures 2 and 3 are configuration diagrams for explaining examples of conventional sunlight collection devices, respectively. In the figures, 1 is a lens for concentrating sunlight, and 2 is a lens for concentrating sunlight. An optical conductor cable through which focused sunlight is introduced. Figure 2 shows an example when the numerical aperture (angle) of lens 1 is large, and Figure 3 shows an example when the numerical aperture (angle) of lens 1 is small. An example is shown.

Therefore, as shown in FIG. 2, when the aperture angle of the lens is large, the sun image formed by the lens 1 is small;
Therefore, it is possible to use a light guide with a small diameter, which is advantageous, but on the other hand, the rising angle 01 at the peripheral part of the lens is large, and therefore the light reflection in this part is large and the focusing efficiency is reduced. Moreover, the incident angle 02 with respect to the optical conductor cable 2 was large, so the reflection at the light receiving end of the optical conductor cable was large, and the introduction efficiency into the optical conductor cable 2 was poor. Furthermore, the light that enters the lens 1 is reflected at the light output end Ia side of the lens, returns to the lens, and thereafter propagates within the lens, making it difficult to efficiently guide the incident sunlight to the optical conductor cable. I couldn't do it.

On the other hand, as shown in FIG. 3, when the angle of the lens is small, the rising angle θ1 at the peripheral part of the lens is small, so the reflection at this part is small, and the optical conductor cable 2
The incident angle is small, and therefore the reflection at the light receiving end of the light guide cable is small, and the collection efficiency is high.
On the other hand, 1. The disadvantage is that the solar image formed by the lens is large and therefore the diameter of the light guide cable must be increased, making the cost of the light guide cable very high.

Purpose The present invention was made in order to solve the above-mentioned drawbacks of the prior art.In particular, the present invention uses a solar light focusing lens with a small numerical aperture to maintain the focusing efficiency of the lens at a high level. At the same time, it is possible to eliminate reflection at the light receiving end of the optical conductor cable to maintain high efficiency of introduction into the optical conductor cable, and to reduce the cost of the optical conductor cable by making it possible to reduce the diameter of the optical conductor cable. It is something that

Configuration FIG. 1 is a configuration diagram for explaining one embodiment of the sunlight collecting device according to the present invention, in which 1 indicates a sunlight condensing lens;
2 is a light guide cable, and 3 is an optical coupling using a truncated cone-shaped light guide with a large area on the light receiving end 3a side and a small area on the light emitting end 3b side.

The condenser lens 1 has a small numerical aperture, in other words,
Use a lens that does not have a very large rise angle at the periphery. Therefore, there is little reflection at the periphery of the lens 1, and sunlight can be efficiently focused by the lens 1. Since the solar image focused by this lens 1 with a small numerical aperture is large, if an optical coupling 3 having a light-receiving area corresponding to the size of this solar image is arranged at the focal position of the lens 1, the solar image focused by the lens 1 will be All of the sunlight is introduced into the optical coupling, and since the aperture angle is small, there is little reflection on the light-receiving end surface 3a of the optical coupling. The light introduced into the optical coupling 3 travels toward the optical conductor cable 2 while being reflected by the wall of the optical coupling, but the angle of the light increases each time it is reflected by the wall. .

Therefore, if the aperture angle of the light emitted from the light emission end 3b of the optical coupling 3 is made equal to the angle of the optical conductor cable 2, the light from the optical coupling 3 can be efficiently introduced into the optical cable 2. can do.

Effects As is clear from the above explanation, according to the present invention, sunlight can be efficiently focused by eliminating reflections around the lens, and moreover, the aperture angle of the light when introduced into the optical conductor cable can be reduced. Since it is made equal to the open angle of the optical conductor cable, light can be efficiently introduced into the optical conductor cable, and sunlight can be efficiently collected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining one embodiment of a solar light collecting device according to the present invention, and FIGS. 2 and 3 are schematic diagrams for explaining examples of conventional sunlight collecting devices, respectively. be. 1... Focusing lens, 2... Light guide, 3... Optical coupling.

Claims (1)

[Claims] It consists of a lens for focusing sunlight, an optical coupling consisting of a truncated conical light guide, and a light guide cable.
The sunlight focused by the lens is introduced into the wide-area end of the frusto-conical optical coupling, and the light emitted from the narrow-area end of the frusto-conical optical coupling is directed into the light guide. In the solar light collection device, the numerical aperture of the light-emitting end of the coupling is made to match the numerical aperture of the light guide cable, and the numerical aperture of the lens is made to match the numerical aperture of the light-introducing end of the coupling. A solar light collecting device characterized in that the numerical aperture matches the numerical aperture of the solar light collecting device.