JPH04188775A - Solar cell - Google Patents

Abstract

PURPOSE:To improve lighting efficiency by concentrating and introducing momently changing solar rays onto a surface in the fixed direction at all times by installing transmission type diffraction gratings having different lattice pitches. CONSTITUTION:A solar cell is composed of a solar cell body 2, diffraction gratings 1, a transparent cover 3 and a housing 4. When solar rays are applied from the upper section of transmission type diffraction gratings 1 having different lattice pitches P1-Pn, the angle of diffraction alpha is kept constant even when the incident angle of solar rays changes as i1-in with time. On the other hand, these lattice pitches P1-Pn are kept constant after the lattice pitches are set once. Consequently, P1-Pn to each incident angle i1-in are set previously so that the angle of diffraction alpha reaches zero, thus converting transmitted light Q1-Qn into light vertical to the substrate of the transmission type diffraction gratings 1, light as the angle of diffraction alpha=0. Accordingly, momently changing solar rays can be concentrated and introduced onto a surface in the fixed direction at all times, thus improving lighting efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in solar cells suitable for use as a power source for residential buildings, office buildings, and the like.

[Conventional technology] Conventional solar cells were constructed as follows.

■Place the solar cell directly on the roof or other mounting area.

■Use a pedestal for the mounting part and install it at a specified angle to the south.

■A solar tracking mechanism is attached and configured to focus light while tracking the sun.

[Problems to be Solved by the Invention] However, the above-mentioned prior art had the first problem.

That is, in the case of the above item (2), the efficiency varies greatly depending on the installation condition.

In addition, the type ■ has a higher daylighting efficiency than the type ■, but the efficiency decreases greatly in the morning and evening, and furthermore, the efficiency of the type ■ is extremely high.

Although this would be an ideal situation, it would be necessary to provide an expensive tracking aircraft tank consisting of a power source and a control mechanism as described above.

In particular, when using large-area solar cells, the system becomes large-scale, extremely expensive, and requires a large amount of energy (tons).
There was a problem (i1 problem) of consuming the amount of F).

An object of the present invention is to provide a solar cell that solves the above-mentioned problems of conventional solar cells.

[Means for Solving the Problems] According to the present invention, a solar cell is provided with a diffraction grating formed of a large number of gratings with different grating pitches on the sunlight incident side.

[Function] In the present invention, by providing a transmission diffraction grating with a different grating pitch on the sunlight incident side, it is possible to always guide the ever-changing sunlight rays into the air in a fixed direction. Because that's what I did.

Even in the morning and evening, the lighting efficiency for the solar cell body hardly decreases.

[Example] Next, a solar cell according to the present invention will be described based on an example shown in FIGS. 1 and 2.

FIG. 1(a) is a longitudinal sectional front view showing the configuration of a solar cell according to the present invention.

In the figure, 1 is a diffraction grating provided on a solar cell main body 2, and 3 is a transparent cover placed on the diffraction grating 1. This cover is made of, for example, a glass plate.

4 is a case that stores these 1 to 3.

As shown in Figures (B) and (C), the 7-diffraction grating 1 is made by coating the surface of a substrate made of a transparent material such as glass or film with photoresist (resin), and then irradiating the grating from above. Lattice with different pitch 1 al+ 1 a2' H
H and lb, , lb, , lb, .

- Formed by etching.

In this case, the photoresist layer is formed into a holographic diffraction grating with a sinusoidal shape as shown in (b) of the same figure, or a rectangular wave as shown in (c) of the same figure. It can also be a laminar diffraction grating formed in

The sun of the present invention is constituted by 1 to 4 above.

Next, the principle of the present invention will be explained using FIG. 2.

Transmission type diffraction gratings 1 with different grating pitches as shown in the figure.
When light is irradiated from above, sin i + sin a = λ/P-(1) holds true, where the incident angle is 11 and the diffraction angle is α.

However, λ is the wavelength of light and P is the grating pitch.

When the grating pitch is set as shown in the figure, the incident angle of sunlight changes over time, for example, l l + 12 + 1,
...i, the single diffraction angle α remains constant as shown in the figure.

On the other hand, once the grating pitch P is set, these values p
HP2+ P3...Pl is constant, so λ/P, ~
λ/P is also constant.

Therefore, from equation (1), each 11
By setting P for ~i in advance, the transmitted light ray becomes a light ray with a diffraction angle α = 0 that is perpendicular to the substrate of the transmission type diffraction grating 1, as shown by Q and ~Q in the figure. can be converted.

Therefore, when the solar cell panel of the present invention is placed on the roof of a building, etc., regardless of the change in the angle of the incident rays due to the movement of the sun, the sunlight rays are made into parallel rays by the diffraction grating 1.
The light is guided to efficiently enter the solar cell main body 2.

[Effects of the Invention] Since the present invention is constructed as described above, it has the following excellent effects.

■Even if the angle and amount of incident light rays change due to the movement of the sun, the transmission diffraction gratings with different grating pitches provided at the entrance part will always maintain the same proper angle on a certain surface (the entrance surface) of the solar cell (main body). ), the amount of incident light can be kept approximately constant during the day.

Lighting efficiency can be improved.

■In this case, the transmission diffraction grating is made of a base material such as glass or film, so it is light and flexible.

Easy to process and install.

(1) Moreover, in the case of the present invention, there is no need to provide a large-scale tracking mechanism like the conventional one, and the structure can be provided on the top surface of a planar daylighting window material, so it is extremely economical and highly practical.

[Brief explanation of the drawing]

FIG. 1(a) is a longitudinal sectional front view showing the overall configuration of a solar cell to which the present invention is applied, and FIG. 1(b) and (c) are examples of holographic diffraction gratings with different grating pitches FIG. 3 is an enlarged cross-sectional view of a grating and a laminar diffraction grating. FIG. 2 is an explanatory diagram drawn to explain the action of the diffraction grating used in the configuration of the present invention. 1: Transmission type diffraction grating 2: Solar cell body 3: Cover 4: Case 5 2. Solar cell applicant Sanyo Electric Co., Ltd. agent Patent attorney Haruya Saito (1 person) Figure 1 (A) (B) (C) 1: Transmission type diffraction grating 2 Solar cell body 6 Cover 4: Case 5゛Solar cell

Claims (1)

[Claims] 1. A solar cell characterized by having a diffraction grating formed of a large number of gratings with different grating pitches on the sunlight incident side.