JPH0476228B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to colored solar cells.

Conventionally, solar cells have been put to practical use in various electrical devices, and amorphous silicon or single crystal silicon is used as the material. However, since the solar cells currently in use are black or a color close to black, they are not aesthetically pleasing, are difficult to use as exterior parts, and have design limitations. Furthermore, when applied outdoors to solar systems, etc., it sometimes darkens the surrounding atmosphere, which is environmentally undesirable.

The present invention solves these drawbacks of the prior art by adding color to the solar cells.

Next, embodiments of the invention will be described.

In FIG. 1, a reflective layer 2 is formed on a solar cell 1, and a light diffusing and transmitting layer 3 is formed thereon. Amorphous silicon or single crystal silicon is currently used as solar cell 1.
The wavelengths that contribute to power generation when these are used as solar cells are shown in Figure 2. The reflective layer 2 may be a multilayer interference filter such as a dichroic mirror or a cold mirror. This selectively reflects visible light of a specific wavelength and transmits light in a wavelength range that contributes to power generation by the solar cell 1. The wavelength of the selectively reflected light is preferably shifted from the wavelength that contributes to power generation by the solar cell 1 shown in FIG. Therefore, in the case of an amorphous silicon solar cell, the color of the reflected light may be red, blue, or violet. On the other hand, in the case of single-crystal silicon, it is desirable that it reflects blue and green colors, but it is possible to produce colors in the entire visible range. White color can also be produced by using a cold mirror.
Figure 2 shows a curve DM showing the transmittance of a blue dichroic mirror and a curve CM showing the transmittance of a cold mirror. For example, amorphous silicon is used as the solar cell 1, and the reflective layer 2 is added to the amorphous silicon.
If you use a blue dichroic mirror DM as a power source, you will hardly lose power generation efficiency.

Furthermore, when using cold mirror CM, it can be seen that single-crystal silicon is better for solar cells than amorphous silicon. A light diffusing and transmitting layer 3 is provided on the reflective layer 2 . As the light scattering and transmitting layer 3, blasted glass or plastic may be used, or instead of this, a matte lacquer or the like may be sprayed onto the surface of the reflective layer 2. This light diffusing and transmitting layer 3 is for making the color of reflected light appear brighter, and without it, it would look black.

In FIG. 3, incident light 4, which is white light, passes through the light diffusing and transmitting layer 3 and is diffused. When a blue dichroic mirror is used as the reflective layer 2, the blue light in this diffused light is reflected and passes through the light diffusing and transmitting layer 3 again.
is diffused and reaches the observer's eyes. On the other hand, most of the yellow light transmitted through the dichroic mirror is absorbed by the solar cell 1. Therefore, in this case, a bright blue color will be visible.

Note that the reflective layer 2 and the light diffusion/transmission layer 3 do not have to be disposed on the entire surface of the solar cell 1, and the reflective layer 2 may be provided in a stripe shape, a halftone dot shape, or the like as shown in the fourth figure. The spacing should be such that when viewed through the light diffusing and transmitting layer 3, the black color and the color of the reflective layer 2 do not appear separated, that is, approximately 0.2 mm to 1 mm, but when viewed from a distance, the spacing is wider. It's okay. Further, if the distance between the light diffusing and transmitting layer 3 and the reflective layer 2 is large, the interval between the stripes may be made wide accordingly. In the case of this embodiment, since the incident light reaches the solar cell 1 as it is in the part where the reflective layer 2 is not provided, for example, when amorphous silicon is used as the solar cell 1, the greenish or yellowish reflective layer 2 is used. It can generate electricity even when used.

Furthermore, the reflective layer 2 can be shaped into a pattern of letters, figures, pictures, etc. to make it more interesting, or a plurality of reflective layers of different colors can be provided on one solar cell.

Since the colored solar cell of the present invention having the above-mentioned structure is colorful, its uses can be expanded as an exterior component, and when it is installed outdoors as a solar system, it can brighten the environment.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a graph showing the relative output of the solar cell and the transmittance of the reflective layer, and FIG. 3 is a cross-section for explaining the operation of the embodiment of FIG. The developed view, FIG. 4, is a sectional view of another embodiment of the present invention. 1...Solar cell, 2...Reflection layer, 3...Light diffusion transmission layer.

Claims (1)

[Claims] 1. A reflective layer that selectively reflects visible light at a specific wavelength and transmits light in a wavelength range that contributes to power generation by the solar cell is provided on the front surface of the solar cell, and a light diffusing and transmitting layer is further provided on the front surface of the reflective layer. Colored solar cells featuring