JPH0846228A - Solar cell device - Google Patents

Abstract

PURPOSE:To provide a solar cell device, a solar cell of which is not visible from the outside and which also has an excellent appearance. CONSTITUTION:A lower plate 7 consisting of a transparent body and an upper plate 8 similarly composed of the transparent body on the lower plate 7 are superposed onto a solar cell board 6, in which solar cells are formed. A first diffusion layer is formed onto the underside of the lower plate 7 and an interference filter layer 11 onto a top face. A second diffusion layer is formed onto the underside of the upper plate 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell device using light as an energy source, and more particularly to a solar cell device suitable for use as a dial for a timepiece.

[0002]

2. Description of the Related Art Conventionally, monocrystalline silicon, polycrystalline silicon and amorphous silicon have been used as solar cells for energy sources such as watches, calculators and radios. Conventionally, some solar cells are used as they are, but the dark blue color of the solar cells appears, which is not preferable in appearance. On the other hand, an apparatus has been proposed in which an interference filter is inserted on the front surface of the solar cell so that the solar cell cannot be seen directly, but there is a problem in that the light energy supply to the solar cell is hindered.

As a solar cell device for solving such a problem, the present applicant has proposed a device provided with a high refractive index material layer and a white diffusion layer which are substantially transparent in the visible region on the front surface of the solar cell. The white diffusion layer is formed by honing the surface of the glass plate with No. 100 SiC powder.

[0004]

However, when the diffusion layer is formed by honing, the glass plate is warped, which makes it difficult to use as a dial for a timepiece. Further, the honing process causes unevenness on the diffusing surface, resulting in color unevenness and poor appearance quality. Further, if the solar cell and the diffusion layer are integrated, the productivity will be extremely poor. Further, the white diffusion layer is formed on the uppermost surface, but it is necessary to attach a decorative portion such as an hour character on the dial plate of the timepiece. However, when the decorative portion is formed on the surface of the diffusion layer, the appearance quality of the decorative portion deteriorates. Especially when the decorative part is formed by printing,
Ink enters the uneven surface formed by honing, and the print shape collapses, resulting in poor print quality.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, to provide a solar cell device which is colorful and can be diversified in design, and which can easily form a diffusion layer and an interference filter layer. .

[0006]

A solar cell device according to the present invention comprises a solar cell substrate on which a solar cell is formed, a lower plate made of a transparent body, and a lower plate provided on the solar cell substrate. An upper plate provided on the plate, a first diffusion layer attached to the lower surface of the lower plate, an interference filter layer formed on the upper surface, and a second diffusion layer formed on the lower surface of the upper plate It is characterized in that

[0007]

In the interference filter layer, the transmittance can be controlled in an arbitrary wavelength range by the combination of the high refractive index material and the low refractive index material and the number of layers. In addition, an interference filter made of a high refractive index material has a high transmittance. Most of the light that reaches the solar cell is absorbed by the solar cell portion, but is partially reflected by the peripheral portion of the solar cell and returns to the outside observer. As a result, the existence of solar cells will be recognized. The first diffusion layer plays a role of preventing the reflected light from returning to the outside observer, and the introduction of this layer makes it possible to make the underlying solar cell visually unrecognizable. The second diffusion layer is inserted in order to uniformly emphasize the reflected light from the interference filter layer to an external observer. With the interference filter layer alone, the reflected light has a directivity and looks glaring, and since the returned light of the transmitted light is also visible, the reflected color and the transmitted color are mixed and the color purity decreases, but this layer is introduced. By doing so, it becomes possible to softly express any bright reflected color without directivity.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view schematically showing a solar cell timepiece using a solar cell device according to the present invention, in which a module 2 is provided in a timepiece case 1 with a core 4 and an inner frame 3 fixed to a case back. It is attached, and the solar cell device 5 is attached thereon.

FIG. 2 is an enlarged sectional view showing a solar cell device, and FIG. 3 is a plan view thereof. The solar cell device 5 according to the present invention has a solar cell substrate 6 having solar cells, and a lower plate 7 and an upper plate 8 placed thereon. The upper and lower plates are transparent plates made of plastic, the upper plate having a thickness of 0.125 mm and the lower plate having a thickness of 0.250 mm. First and second colored diffusion layers 9 and 10 are formed on the lower surfaces of the upper and lower plates 8 and 7, respectively. As a light diffusing agent, a high-purity calcium carbonate or calcium phosphate, a light diffusing pigment having a special crystal structure in which 3 to 5 kinds of additives are added, a binder, and an ink or paint consisting of a thinner are used for screen printing. It is formed by printing or painting such as method.

The mixing conditions of the diffusing agent are as shown in Table 1.

[Table 1] The medium in the table is the binder and the diluent is the thinner. As the binder, there are acrylic resin, epoxy resin, etc., and acrylic resin was used in this embodiment. Also,
Toluene or xylene was used as the thinner. The pigment, the medium, and the diluent are mixed and mixed well to form an ink, which is then screen-printed to 5 μm to 30 μm.
The thick first and second colored diffusion layers 9 and 10 are attached to the upper and lower plates 8,
7 to form. The optimum thickness of the colored diffusion layers 9 and 10 is 15 μm for the colored diffusion layer 9 and 10 μm for the colored diffusion layer 10.

The upper surface of the lower plate 7 is made of Z as a high refractive index material.
The interference filter layer 11 is formed by using nO ₂ and SiO ₂ as the low refractive index material. As shown in FIG. 3, the upper and lower plates 8 and 7 have a fixing projection 12
Are projected, and the upper and lower plates are bonded at this portion.
On the upper surface of the upper plate 8, hour characters 13 such as Roman numerals are formed by printing or the like to form a dial plate.

As shown in FIG. 1, the portion of the protrusion 12 is the middle frame 3
And is held between the step portion of the case 1.

The upper and lower plates having the above construction have the transmittances shown in Table 2. This Table 2 shows the Isc measurement results. In addition, the transmittance referred to here represents the power generation characteristics of the solar cell, and a device that prevents external light from entering a certain light source, irradiating the solar cell placed at a certain distance with light, The current value when light energy is converted to electric energy is 100%, the upper and lower plates according to the present invention are placed on the upper surface of the solar cell, and the current value when light energy at that time is converted to electric energy is expressed as a percentage. .

[0014]

[Table 2]

Looking at Sample 1 in Table 2 above, it is shown that the current value when the light energy of the solar cell was converted into electric energy was 51.9% due to the influence of the upper and lower plates. That is, the power generation characteristics were down by 48.1% due to the influence of the upper and lower plates.

The colored diffusion layers 9 and 10 have a white color tone,
The first colored diffusion layer 9 was used as the first white diffusion layer, and the second colored diffusion layer 10 was used as the second white diffusion layer. The interference filter layer 11 uses ZnO ₂ and SiO _{2 and} has a gray appearance. The transmittance of this interference filter layer 11 is 80%.
Met. When the interference filter layer 11 is used in combination with the second white diffusion layer, the bright white appearance due to the high reflectance at the interface and the light energy other than the bright white appearance all pass through to reach the solar cell. It is possible to achieve both the securing of electromotive force characteristics. Further, the second white diffusion layer has a function of recognizing the appearance color by returning the reflected light from the interference filter layer 11 to the observer as scattered light.

Further, the interference filter layer 11 may be formed of a single layer of a high refractive index material. In this case, TiO ₂ having a refractive index of 2.30 is used as a material, and the film is deposited to about 54 nm by color vapor deposition.

In this case, the interference layer 11 made of a high refractive index material
Indicates the reflectance due to the difference in refractive index at the interface with another medium, and the higher the refractive index, the higher the reflectance. Therefore, the reflected light intensity is increased and bright reflected light can be obtained. Therefore, if an almost transparent interference filter layer that does not absorb in the visible region is used in combination with the white diffusion layer 9, a bright white appearance due to the high reflectance at the interface and all other light energy are transmitted. It is possible to achieve both the securing of the electromotive force characteristic of the solar cell by reaching the solar cell. Further, the diffusing layer can be a surface on which the reflected light from the interface between the filter layer and another medium shines uniformly as scattered light to an external observer.

[0019]

According to the present invention, by forming each layer on the upper plate and the lower plate, an appearance similar to that of the painted dial can be obtained. Further, by forming a filter on the lower plate by color vapor deposition, the same color tone as various color coatings can be obtained. Further, the formation of the diffusion layers 9 and 10 is restricted by the conditions such as the material, but it can be easily formed by providing the diffusion layer by printing such as screen printing or painting. The diffusing material can also be colored.

Since the diffusion layer is not formed by honing, the plate does not warp and can be used as a dial for a timepiece. Furthermore, since there is no diffusion layer on the upper surface of the upper plate, it is possible to print letters, numbers, patterns, etc. on the upper surface of the upper plate or to form a high-quality decorative member by a separate member, and to make a high-quality dial plate. it can.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a solar cell timepiece using a solar cell device according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a solar cell device.

FIG. 3 is a plan view thereof.

[Explanation of symbols]

 1 Watch Case 2 Module 3 Middle Frame 4 Core 5 Solar Cell Device 6 Solar Cell Substrate 7 Lower Plate 8 Upper Plate 9, 10 Colored Diffusion Layer 11 Interference Filter Layer 12 Fixing Protrusion 13 Time Letter

Claims (5)

[Claims] 1. A solar cell substrate having a solar cell formed thereon,
A lower plate made of a transparent body and provided on the solar cell substrate, an upper plate also made of a transparent body and provided on the lower plate, a first diffusion layer attached to the lower surface of the lower plate, and an upper surface A solar cell device comprising an interference filter layer formed and a second diffusion layer formed on the lower surface of the upper plate. 2. The diffusion layer is formed of ink or paint containing a diffusion pigment.
The solar cell device described. 3. The solar cell device according to claim 1, wherein a decorative member is formed on the upper plate. 4. The solar cell device according to claim 3, wherein the decoration member is formed by printing letters, numbers, patterns, or the like or is formed by another member. 5. The solar cell device according to claim 4, wherein the upper plate is configured as a display plate.