JPS6184608A - Condenser - Google Patents

Abstract

PURPOSE:To condense light at a high rate by forming a layer contg. a fluorescent substance on the surface of a transparent substrate and by using a substance whose refractive index is nearly equal to that of the substrate as the base of the layer for holding the fluorescent substance. CONSTITUTION:A layer 2 contg. a fluorescent substance is formed on the surface of a transparent substrate 1 of methyl methacrylate resin, polycarbonate resin or the like, and a substance whose refractive index is nearly equal to that of the substrate 1 such as methyl methacrylate resin or polycarbonate resin is used as the base of the layer 2 for holding the fluorescent substance. Light trapped and scattered by the fluorescent substance is guided through the substrate 1 with little loss in the quality, and it can be condensed at a high rate at a proper cross-section of the substrate 1. The mechanical strength of the resulting condenser can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a light condenser, and more particularly to a light condenser that uses a fluorescent substance to trap light energy and scatter the emitted light.

[Prior Art] So-called concentrators, which introduce external light to cause fluorescent substances to emit light and concentrate the scattered light to increase the amount of energy per unit area and irradiate equipment such as solar cells, have been around for a long time. A,
GOETZBERGERet al, ga J, Appl
ied Physics (upper 4,123-139.'
77), and subsequently published papers by research groups such as the above researchers, as well as E, BERMAN (4th ECPh).
.

tovoltaic Sol, Energy Co
Papers have been published by research groups such as nf,), D, and 5ARTI. The light condenser disclosed in these patents includes a transparent substrate that contains an i6 optical substance held in the transparent body constituting the plate, and the external light generated by the optical substance traps external light. This method guides and focuses scattered light with a longer wavelength than that on the edge of the substrate.In addition, the above literature states that reducing the thickness of the transparent substrate is effective in increasing light collection efficiency. has been pointed out.

Furthermore, JP-A-55-21099, JP-A-55-2
No. 1100, JP-A No. 55-22794, and JP-A No. 57-97683 also disclose a method in which a fluorescent substance is held in a translucent material and the trapped and scattered light is focused on an end face in one direction. A light concentrator is disclosed.

[Problems to be Solved by the Invention] As mentioned above, all conventionally known concentrators have a substrate uniformly containing a fluorescent substance throughout;
There has been a trend toward thinner substrates to increase light collection efficiency. For this reason, mechanical strength was not necessarily sufficient. In addition, in conventional concentrators, since light is guided through a layer containing a fluorescent material, extinction (thermal conversion) due to collision of photons with each other is likely to occur, resulting in a large amount of energy loss.

[Means for Solving the Problems] According to the present invention, the problems of the prior art as described above are solved, and a fluorescent substance-containing layer is formed on at least a part of the surface of a transparent base material. A light condenser is provided, wherein the material constituting the fluorescent material-containing layer and holding the fluorescent material is a transparent body having approximately the same refractive index as the transparent base material.

In the concentrator of the present invention, external light trapped by the fluorescent material is guided into the transparent base material without interfacial reflection, and the light guided through the transparent base material travels through the base material and is guided into the transparent base material without interfacial reflection. The light is focused at the edge of the material.

Hereinafter, the present invention will be explained in more detail based on the drawings.

FIG. 1 is a schematic cross-sectional view showing an embodiment of the condenser of the present invention.

In the figure, 1 is a transparent base material, and 2 is a fluorescent substance-containing layer.

As the material for the transparent base material 1, methyl methacrylate resin, polycarbonate resin, etc. can be used, and methyl methacrylate resin is particularly preferable from the viewpoint of transparency and ease of manufacture.

The fluorescent substance-containing layer 2 contains an appropriate fluorescent substance, and the fluorescent substance is held by an appropriate transparent material such as methyl methacrylate resin, polycarbonate resin, or the like. A material that has approximately the same refractive index as the transparent base material 1 is used as the material that holds the fluorescent material, and it is preferable to use the same material as the transparent base material 1.A combination of the fluorescent material and its holding material is used. As a product, Bayer LI
SA KL3-9402EX, 61R can be exemplified.

FIG. 2 is a partial schematic sectional view showing an example of the condenser of the present invention.

The transparent base material 1 and the fluorescent substance-containing layer 2 are the same as those in FIG.

The transmission dissipation prevention layer 3 is made of a substance having a refractive index smaller than that of the transparent material constituting the fluorescent substance-containing layer 2 . An example of such a substance is polytrifluoroethyl methacrylate.

By providing the light transmission and dissipation prevention layer 3 as in this example, the light trapped and scattered by the fluorescent substance is prevented from escaping into the atmosphere.

FIG. 3 is a partial schematic sectional view showing an example of the condenser of the present invention.

The transparent substrate 1 and the fluorescent substance-containing layer 2 are the same as in FIG. In this example, a protective layer 4 is formed on the fluorescent substance-containing layer 2 .

The protective layer 4 can be constituted by a layer containing an ultraviolet absorber, such as Tinuvin P manufactured by Ciba Geigy, which absorbs ultraviolet rays having a shorter wavelength than the absorption wavelength of the fluorescent substance contained in the fluorescent substance-containing layer 2. Further, the protective layer 4 can be made of an appropriate material having oxygen blocking ability, such as polyacrylonitrile. Although this example shows an example in which the protective layer 4 is formed on the fluorescent substance-containing layer 2, the protective layer 4 may be formed on the light transmission dissipation prevention layer 3 shown in FIG. .

By providing the protective layer 4 as in this example, the concentrator is prevented from becoming brittle due to ultraviolet irradiation or oxidized by oxygen in the atmosphere, and its lifespan is extended.

FIG. 4 is a schematic cutaway perspective view showing an example of the condenser of the present invention.

In this example, the transparent base material 1 is a rod-shaped body having a circular cross-sectional shape, and the fluorescent substance-containing layer 2 is formed on its outer surface.

[Examples] Examples will be described below, but it goes without saying that these are examples of embodiments of the present invention and that the present invention is not limited thereto.

Example 1: 3 g of the fluorescent substance Pelleft [Concentray manufactured by Bayer AG] LISA was dissolved in 30 cc of methyl ethyl ketone,
Add the same amount of xylene by volume to this and mix thoroughly.
A fluorescent solution was prepared.

40mm x 100mm x transparent plate with smooth surfaces on both sides
The fluorescent solution was applied to one side of a 5 mm thick methyl methacrylate resin plate (Acrylite (registered trademark) manufactured by Mitsubishi Rayon Co., Ltd.) and air-dried to form a 0.05 mm thick fluorescent material-containing layer.

On the other hand, a solution with a concentration of 5% was prepared by dissolving polytrifluoroethyl methacrylate in ethyl acetate, and this was applied onto the previously formed fluorescent substance-containing layer and air-dried.
A light transmission and dissipation prevention layer having a thickness of ~0.015 mm was formed.

The four end faces of this plate-shaped body were polished, and an aluminum vapor-deposited film was attached to three end faces except for one side of the end face having a length of 40 mm.

10 mm on both sides of the end face of the condenser obtained by cutting, to which no aluminum vapor-deposited film was attached, was coated with black paint to block light. Then, a photo sensor [5PD-540 manufactured by Sharp Corporation, effective light receiving surface 2
0XIO mml was fixed, and the upper and lower light-receiving surfaces of 2.5 x 20 mm protruding from the opening were masked with black vinyl tape. An ammeter with a minimum scale of 0.1 A was connected to the output terminals of the two poles of the photosensor to measure the generated current I1. Measurements were carried out in August at around 4:00 pm under scattered light conditions with no direct light reaching the sky, with the fluorescent material-containing layer of the condenser pointing toward the sky. As a result, the current value generated by the photosensor was 146 gA.

Separately, for comparison, the current value generated by the photosensor was measured under the same conditions with the condenser removed, and the current value was 72 tiles A.

Example 2: Circular methyl methacrylate resin rod with a cross section of 10 mm in diameter (acryrod registered trademark, manufactured by Mitsubishi Rayon Co., Ltd.)
) was cut into a length of 30 mm, and the cut end surface was polished. The same fluorescent solution as used in Example 1 was applied to the surface of the rod 2 except for the end surface, and the fluorescent solution was air-dried to give a luminescence concentration of 0.05 to 0.0.
A 7 mm thick fluorescent substance-containing layer was formed.

Furthermore, the same polytrifluoroethyl methacrylate solution used in Example 1 was applied onto the fluorescent material-containing layer and air-dried to form a light scattering prevention layer having a thickness of 0.01-0.015 mm.

This rod-shaped body was heated to 100 to 120°C in an air furnace and bent into a U-shape.

In the condenser thus obtained, as a result of naked eye observation,
It was confirmed that the trapped and scattered light was emitted almost equally from the two end faces. In addition, Example 1
In the same manner as above, the light-receiving surfaces of photosensors 5PD-540 were fixed facing each other on each end face, and the outputs from these two photosensors were added and measured using 9 parallel connections. The 111 determination method and measurement conditions were the same as in Example 1. As a result, the generated current value was 273. It was A. The current value generated by the photosensor was measured with the condenser removed in the same manner as in Example 1, and the current value was 121 amps.

Example 3: A fluorescent solution similar to that used in Example 1 was applied to the surface of a small diameter rod of methyl methacrylate resin having a diameter of 2 mm and a length of 2000 mm, approximately at a length of about 100 mm in the center, and the rod was air-dried. A phosphor-containing layer with a thickness of 0.08 mm was formed.

Furthermore, the same solution of polymethacrylic trifluoroethyl as used in Example 1 was applied to the surface of the small diameter rod over the entire length thereof and air-dried to form a light transmission and dissipation prevention layer of 0.01 mm 1'.

When the long condenser thus obtained was freely bent and both end faces were observed with the naked eye, it was confirmed that the trapped and scattered light was emitted almost equally from the two end faces as colored light. .

[Effects of the Invention] According to the concentrator of the present invention as described above, the light trapped and scattered by the fluorescent substance in the fluorescent substance-containing layer is guided through the transparent base material with almost no loss in light amount, Therefore, light can be collected at a high light collection rate on an appropriate end face of the transparent base material.

Furthermore, according to the uninvented light concentrator, a good light condensing rate can be obtained even if the thickness of the transparent base material is relatively thick, so that the mechanical strength can be increased while maintaining the optical properties.

[Brief explanation of drawings]

1, 2rA, and 3 are cross-sectional views of the concentrator of the present invention. FIG. 4 is a cutaway perspective view of the condenser of the present invention.

Claims (5)

[Claims] (1) A fluorescent substance-containing layer is formed on at least a part of the surface of the transparent base material, and a substance that constitutes the fluorescent substance-containing layer and holds the fluorescent substance has approximately the same refractive index as the transparent base material. A light concentrator characterized by being transparent. (2) The transparent base material is a methyl methacrylate resin.
A concentrator according to claim 1. (3) The condenser according to claim 1 or 2, wherein the fluorescent substance-retaining substance is a methyl methacrylate resin. (4) A light condenser according to any one of claims 1 to 3, wherein a light transmission and dissipation prevention layer made of a material having a refractive index smaller than that of the fluorescent material-retaining material is formed on the fluorescent material-containing layer. (5) A collection according to any one of claims 1 to 4, which contains an ultraviolet absorber that absorbs ultraviolet rays with a shorter wavelength than the absorption wavelength of the fluorescent substance and/or has a transparent protective layer made of an oxygen-blocking substance. Light device.