JP2001173169A - Low reflective roof using transparent board and outer wall member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the roof of a dwelling and a member for a wall face low in reflectance from a light incident face used for the roof of the dwelling and the wall face, small in reflection glittering and excellent in productivity. SOLUTION: On the roof and the outer wall member laminating a transparent conductive film, a photoelectric conversion element and a rear face electrode in the order on the side on which a beam is incident and one main surface of the transparent board of the contrary side, the roof and the outer wall member forming a transparent intermediate film comprising at least two layers between the transparent board and the transparent conductive film are manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roof and outer wall members using a transparent substrate having at least two layers formed thereon. More specifically, the present invention relates to a member for a roof and an outer wall in which reflection glare is suppressed by reducing the reflectance on the light incident side.

[0002]

2. Description of the Related Art In recent years, demand for energy, particularly electric energy, has been increasing. Construction of new power plants is not easy due to thermal power generation using oil and coal due to the depletion of raw materials and fuel in the future, and nuclear power generation using uranium etc. due to environmental problems, which have recently become a major problem. .

[0003] Therefore, the government is examining to supplement the power shortage with new energy such as solar power generation. In Japan, where the land is small, solar power generation was mainly planned with solar cells installed on the roofs and walls of houses. Until now, such solar cells for power use
Crystalline or polycrystalline silicon has been used. However, when solar cells are manufactured in large quantities, there is a concern that silicon as a raw material is insufficient. Therefore, use of an amorphous silicon solar cell that uses less raw material silicon than a crystalline silicon or polycrystalline silicon solar cell is being studied.

[0004] Conventionally, amorphous silicon solar cells have often been used as power supplies for calculators and watches. Since the solar cells for these devices are not required to be outdoors, such as the roof of a house, and have a small area, the glare of reflection from the light incident surface of the solar cells has hardly been a problem.

[0005] However, when used on the roof or wall of a house, the area becomes large and easily noticeable, which causes a problem of light pollution to nearby houses due to reflection of sunlight. In particular, if the window of the house next to the north is higher than the installation position of the solar cell, this will give a great deal of discomfort to the residents next to the north.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and it is intended to improve the reflectance from a light incident surface used for a roof or a wall of a house. It is an object of the present invention to provide a member for a roof or a wall surface of a house having a photovoltaic function which has a low reflection, low reflection glare, and excellent productivity. As described above, the use of photovoltaic elements such as solar cells as roofs and outer wall members has increased in recent years, but when used for such applications, the conversion efficiency and the like as photovoltaic elements have been increased. The influence of reflected light not only on the characteristics but also on the appearance and the neighborhood is a major problem, but such a problem has hardly been solved at present.
It is a long-known technique to increase the conversion efficiency of a photovoltaic element such as a solar cell by forming a film according to a so-called non-reflection condition on the light incident side. However, in this case, since the purpose is to improve the conversion efficiency, the wavelength at which the reflectance is the lowest is adjusted to the location at which the spectral sensitivity of the photovoltaic element is the highest. That is, the reflectance of a specific wavelength is reduced, but the reflectance of the entire wavelength is not reduced.

[0007]

That is, the present invention has been made to solve the above-mentioned problems, and the present invention according to claim 1 is directed to one of the transparent substrates on the side opposite to the side on which light rays are incident. In a roof and an outer wall member in which a transparent conductive film, a photoelectric conversion element, and a back electrode are sequentially laminated on a surface, a transparent intermediate film composed of at least two layers is formed between the transparent substrate and the transparent conductive film. Roof and outer wall members. According to the second aspect of the invention, by adjusting the refractive index and the film thickness of the transparent intermediate film, the average reflectance and the reflection interference color from the light incident side are reduced as compared with the case where the transparent intermediate film is not provided. Roof and outer wall members. According to a third aspect of the present invention, there is provided a roof and an outer wall member in which at least one transparent coating is formed on the other main surface of the transparent substrate on which light rays are incident. The invention according to claim 4 is a roof and an outer wall member in which the average reflectance from the light incident side is reduced by adjusting the refractive index and the film thickness of the transparent film as compared with the case where the transparent film is not provided. It is. According to a fifth aspect of the present invention, the side of the transparent substrate where the light beam enters is
A roof and an outer wall member that have been subjected to an anti-glare treatment so that incident light is irregularly reflected. In the invention according to claim 6, the transparent intermediate film has a refractive index of 1.7 to 2.5,
A first transparent interlayer having a thickness of 50 nm, and
A second having a refractive index of 45 to 1.8 and a film thickness of 5 to 50 nm;
And a roof and outer wall member, wherein the first transparent intermediate film has a refractive index higher than the refractive index of the second transparent intermediate film. In the invention according to claim 7, the transparent film has a refractive index of substantially 1.2 to 1.45,
A roof and an outer wall member which are a coating having a thickness of 50 to 200 nm. The transparent film formed on the transparent substrate has a refractive index of 1.6 to 2.0, a thickness of 50 to 200 nm, and a transparent film formed thereon. Is a roof and an outer wall member, which are two-layer coatings having a thickness of 1.25 to 1.8 and a thickness of 30 to 150 nm.

Hereinafter, the present invention will be described in detail. As described above, the present inventor has found that by forming a transparent intermediate film between a transparent substrate and a transparent conductive film, the average reflectance and the reflection interference color from the light incident side are reduced, and the light is incident on the light incident side of the transparent substrate. When the transparent film is formed, the reflectance of the entire visible light region on the light incident side is reduced, the conversion efficiency of the photovoltaic element is improved, and the glare of the reflection from the light incident side is greatly reduced. When the solar cell, which is a photovoltaic element, is installed on the roof of a house, it has been found that reflected light pollution is reduced, and that discomfort caused by reflected light can be reduced. Furthermore, in order to further reduce glare due to reflection, it is preferable to perform an anti-glare treatment on the surface of the transparent substrate on the light incident side.

A transparent intermediate film for realizing this is a first transparent intermediate film having a refractive index of 1.7 to 2.5 and a film thickness of 5 to 50 nm on the transparent substrate side, and 1.45 on the first transparent intermediate film. A second transparent intermediate film using a second transparent intermediate film having a refractive index of ~ 1.8 and a film thickness of 5-50 nm, wherein the refractive index of the first transparent intermediate film is the second transparent intermediate film Is a coating having a refractive index larger than

Examples of the thin film having a refractive index of 1.45 to 1.8 include silicon oxide, silicon oxide containing carbon or nitrogen, aluminum oxide, and a metal oxide film mainly containing silicon or aluminum. Judging from the viewpoint that film formation can be easily performed, when a CVD method described later is used, silicon oxide, silicon oxide containing carbon or nitrogen,
And aluminum oxide are preferred.

As a thin film having a refractive index of 1.8 to 2.5, tin oxide,
Indium oxide, zinc oxide, titanium oxide and the like can be mentioned. In the CVD method, tin oxide or titanium oxide is preferable from the viewpoint of easy availability, easy film formation, and relatively inexpensive raw materials.

If the thickness of these transparent intermediate films deviates from the above and is too thin, a uniform film cannot be formed on the transparent substrate, and the effect of reducing the reflectance may not be obtained. Conversely, if the thickness is deviated from the above, not only the reflection interference color will not be reduced, but also the production cost will increase due to the need for a large amount of raw materials, and the film formation rate will be slow and time-consuming, and the productivity will deteriorate, resulting in a low production cost Problem arises. Therefore, the thickness of the transparent intermediate film is preferably 5 to 50 nm.

The reason why the refractive index of the first transparent intermediate film is made larger than the refractive index of the second transparent intermediate film within the range of the thickness of the transparent intermediate film is to reduce the reflection interference color. It is.

Next, the transparent film having a refractive index of 1.2 to 1.45 may be a porous silicon oxide or a film mainly composed of silicon oxide. The preferable thickness is 50 to 200 n.
m. The reason for this is that if it is less than 50 nm, there is almost no effect of reducing reflection, and if it exceeds 200 nm, the effect of reducing reflection at a wavelength effective for the solar cell is reduced, and the productivity is lowered and the production cost is increased. It is. The transparent coating as the reflection reducing layer may be formed by a multilayer film of two or more layers. In this case, in order to reduce the reflectance, the refractive index of the transparent coating on the transparent substrate side is formed on the transparent coating. It is preferable that the refractive index be larger than the refractive index of the transparent film.

Here, it is necessary to adjust the respective film thicknesses corresponding to the refractive indices of the respective coating layers. The refractive index of the transparent film is 1.6 to 2.0, and the film thickness is 50 to 200 nm.
Thus, the refractive index of the transparent film formed thereon is 1.25 to
It is preferable that the thickness be 1.8 to 30 to 150 nm.

The transparent film having a refractive index of 1.6 to 2.0 includes, for example, a film mainly composed of titanium oxide, tin oxide, aluminum oxide and silicon oxide, and a mixed film thereof. Examples of the transparent film having a refractive index of 1.25 to 1.8 include these oxides, particularly silicon oxide and aluminum oxide, those having a high ratio of silicon oxide and aluminum oxide in a mixed film thereof, and porous silicon oxide film. No.

Although the transparent substrate may be a transparent resin or the like, when a solar cell is used for a roof of a house or the like, a glass plate is preferable in terms of fire resistance, durability and impact resistance.

Examples of the transparent conductive film include tin oxide to which fluorine, chlorine or antimony is added, indium oxide to which tin is added, and zinc oxide to which aluminum or indium is added. It is preferable to use tin oxide from the viewpoint of film material. Further, tin oxide containing at least one selected from fluorine, chlorine and antimony is preferable.

As a method for forming these thin films, a so-called physical method such as a vacuum evaporation method using each metal or each metal oxide, a sputtering method, an ion plating method, or a gaseous vapor of each metal compound is used. Chemical vapor deposition method (CVD method) in which a film is sprayed on a heated glass substrate, a spray method in which droplets of a solution in which each metal compound is dissolved are sprayed on a heated glass substrate, or a powder made of a metal compound. A so-called chemical method such as a powder spray method for spraying a body may be used.

Among these, film formation by a physical method is excellent in uniformity of film thickness, but is difficult in mass productivity in that the cut glass is washed and formed in a vacuum apparatus. In addition, the chemical method is superior in terms of responding to an increase in the size of the glass substrate.

In addition, among the chemical methods, the spray method has an advantage that the film can be formed at low cost because the method is simple. However, it is difficult to control droplets to be sprayed and to control products to be evacuated such as reaction products and undecomposed products, so that it is difficult to obtain uniform film thickness. Further, it has a drawback that the distortion of the glass becomes large. As described above, the CVD method is more suitable as a method for producing a transparent conductive film or a transparent thin film.

When each metal oxide film is formed by the CVD method, a glass substrate cut to about 500 mm square is generally heated and sprayed with a gaseous metal compound to form a film. However, recently, when a glass substrate with a transparent conductive film on which such various thin films are formed is used for a roof of a house or the like for an amorphous solar cell, it is necessary to further increase the size of the glass substrate.

When a large-area cut glass substrate is heated and sprayed with a gaseous metal compound to form a film,
Heating requires a lot of heat energy. For this reason, when obtaining a transparent conductive film forming glass substrate having a large area,
It is desirable from the viewpoint of manufacturing cost, quality, and the like, to continuously form a film on a high-temperature glass ribbon by a CVD method using thermal energy during glass molding.

The silicon source of the silicon oxide formed by the CVD method includes monosilane, disilane, trisilane, monochlorosilane, dichlorosilane, 1,2-dimethylsilane, 1,1,2-trimethyldisilane, 1,1, 2,2-tetramethyldisilane, etc., as oxidizing agents, oxygen, steam,
Dry air, carbon dioxide, carbon monoxide, nitrogen dioxide and the like can be mentioned.

Further, when silane is used, ethylene, acetylene, and the like are used for the purpose of preventing oxidation until reaching the glass surface and controlling the refractive index of the obtained silicon oxide film.
An unsaturated hydrocarbon gas such as toluene may be added.

Examples of the aluminum raw material for the aluminum oxide include trimethylaluminum, aluminum triisopropoxide, diethylaluminum chloride, aluminum acetylacetonate, and aluminum chloride.

As the titanium raw material of titanium oxide formed by the CVD method, titanium tetrachloride, titanium isopropoxide and the like can be mentioned.

As tin compound raw materials used in the CVD method, tin tetrachloride, dimethyltin dichloride, dibutyltin dichloride, tetrabutyltin, tetramethyltin, dioctyltin dichloride, monobutyltin trichloride, etc. are used to obtain tin oxide. Examples of the oxidizing agent include oxygen, steam, and dry air.

Further, in order to increase the conductivity of tin oxide, the addition of fluorine with hydrogen fluoride, trifluoroacetic acid, bromotrifluoromethane, chlorodifluoromethane or the like, or the addition of antimony with antimony pentachloride or antimony trichloride, etc. Etc. are performed.

In order to improve various characteristics other than the above-mentioned elements, silicon, aluminum, zinc, copper, indium, bismuth, gallium, boron, vanadium, manganese, zirconium, etc. are added in a range where the sheet resistance is not so large. You may add suitably.

The tin oxide film, which is a transparent conductive film, and the silicon oxide film, the aluminum oxide film and the like formed between the transparent substrates prevent sodium in the glass from penetrating into the tin oxide film and lowering the conductivity. It also has the purpose of preventing (so-called alkali barrier layer).

Next, as a method for forming an amorphous silicon film, a plasma CVD method using plasma energy is generally used. As a material for forming a film by the plasma CVD method, monosilane, disilane, or the like is used. It is generally used.

When forming an amorphous silicon solar cell, it is necessary to provide p-type and n-type semiconductor layers of amorphous silicon. When obtaining a p-type semiconductor layer, it is common to add diborane or the like to monosilane or the like, and to obtain an n-type semiconductor layer, it is common to add phosphine or the like.

In addition to the amorphous silicon layer as the semiconductor thin film, it is more preferable to form an oxide semiconductor thin film such as zinc oxide for the purpose of reducing reflection color unevenness and adjusting reflection color.

As a metal electrode film formed on an amorphous silicon film or a zinc oxide film, aluminum, silver or the like is generally used. As a method for forming these metal electrode films, a so-called physical method such as a vacuum evaporation method or a sputtering method using these metal targets is generally used.

The roof and the outer wall member of the present invention are formed, for example, by stacking a transparent thin film made of a silicon oxide film, a tin oxide film, a titanium oxide film or the like on a glass substrate by a CVD method.
A tin oxide film, which is a transparent conductive film, is laminated thereon, an amorphous silicon film as a semiconductor thin film or a zinc oxide film is formed on the amorphous silicon film, and then an aluminum film is laminated as a metal electrode film. It is made. The film forming method may be a combination of other methods such as the vacuum evaporation method, the sputtering method, the CVD method, and the spray method.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, Examples and Comparative Examples
The present invention will be described in more detail.

(Examples 1 and 2 and Example 4) Ordinary soda-lime-silica glass was melted in a melting furnace, the molten material was poured into a tin bath, and the glass was formed into a plate by a so-called float manufacturing method. The thickness of the sheet glass was adjusted to 3 mm. The atmosphere gas composition of the tin bath consisted of 98% by volume of nitrogen and 2% by volume of hydrogen, the pressure of which was maintained at a slightly more positive pressure than the surroundings.

When the sheet glass passes below the plurality of film forming nozzles 15 in the first half in the tin bath shown in FIG. 2, a mixed gas comprising vapor of dimethyltin dichloride, oxygen, water vapor, helium and nitrogen Was used to form a coating made of tin oxide on a sheet glass. When passing below the film-forming nozzle 16, it was treated with a mixed gas composed of monosilane, ethylene, oxygen and nitrogen, and a film mainly composed of silicon oxide was formed.

Next, when passing under the plurality of nozzles 18 in the latter half, it is treated with a mixed gas consisting of vapor of dimethyltin dichloride, oxygen, water vapor, nitrogen and hydrogen fluoride. A tin film was formed with a thickness of about 750 nm. The thickness of each coating was controlled by changing the concentration of the raw materials used. This sheet glass is 450 m in a cutting process after a slow cooling process.
It was cut into a glass plate measuring mx 450 mm.

Next, the glass plate on which the tin oxide film is formed is sufficiently washed and dried, and then a capacitively coupled high-frequency glow discharge is performed under a pressure of about 170 Pa using a mixed gas containing hydrogen and monosilane gas. An amorphous silicon solar cell was formed using the apparatus. The configuration of the amorphous silicon solar cell is as shown below. The glass substrate temperature was 220 ° C. The thickness of the amorphous silicon film was controlled by the film formation time.

On the amorphous silicon formed according to the above procedure, an aluminum layer is formed as a back electrode at 10 ^-4 Pa.
A solar cell was formed by vacuum evaporation to a thickness of about 300 nm under a moderate pressure, and this glass was 430 mm × 4
It was cut into a size of 30 mm.

In the formation of the transparent thin film and the transparent conductive film, before and after forming these multilayer films, a film formation for forming only a single layer film is performed.
The refractive index and thickness of the transparent thin film and the thickness of the transparent conductive film were determined by the following methods.

The refractive index of the silicon oxide film was determined at a wavelength of 633 nm using ellipsometry (the refractive index of aluminum oxide, tin oxide and titanium oxide was also determined by the same method).

The thickness of the silicon oxide was determined by setting the extinction coefficient of the coating to 0 when the refractive index was measured by ellipsometry (the thickness of the aluminum oxide was also determined by the same method).

The thickness of the tin oxide was determined by applying a zinc powder to the tin oxide film masked with a tape, pouring dilute hydrochloric acid on the tin powder, etching the coating, and using a stylus meter (of titanium oxide). The film thickness was determined by the same method).

Next, the visible light reflection color of the obtained amorphous silicon solar cell was measured with a Hitachi 330 type spectrophotometer according to JIS Z 8722-1982 to obtain the values shown in Table 1.

The presence or absence of the reflection interference color and the glare of the reflection can be determined by placing the amorphous silicon solar cell sample prepared above on a white wall with the surface on which the film is not laminated facing up, and irradiating the surface with light for 1 m. It was based on visual judgment from a distance. The results are shown in Table 1.

Example 3 An ordinary soda-lime-silica glass plate having a thickness of about 1 mm cut into a size of 450 mm × 450 mm was placed on a mesh belt and heated to about 570 ° C. through a heating furnace.

The glass plate was passed under the first film-forming nozzle to form a film made of titanium oxide on the glass using a mixed gas consisting of titanium isopropoxide, oxygen and nitrogen. Once the glass plate on which this coating was formed was taken out through a slow cooling step, the glass plate was placed on a mesh belt again and passed through a heating furnace for about 600 hours.
After heating to ° C, a film mainly composed of aluminum oxide was formed on a glass plate using a mixed gas composed of aluminum isopropoxide, oxygen, and nitrogen by passing below a plurality of film forming nozzles. Next, the glass plate is gradually cooled, taken out, and reheated at 600 ° C., and then passed under a plurality of film forming nozzles to be treated with a mixed gas consisting of monobutyltin trichloride vapor, oxygen, water vapor, nitrogen and trifluoroacetic acid. And a coating of tin oxide of about 750 n
m was formed.

Using the obtained glass substrate, an amorphous silicon solar cell was formed in the same manner as in Example 1, and 430 m
After cutting to a size of mx 430 mm, the same evaluation as in Example 1 was performed. The results were as shown in Table 1.

(Example 5) In the same manner as in Example 1, a tin oxide film, a silicon oxide film and a film thickness of about 7
A 50 nm thick tin oxide film was formed in this order to form a transparent conductive film. The sheet glass on which these coatings are formed is 450 mm × 450 mm in a cutting process through a slow cooling process.
Cut into glass plates of dimensions. Next, using the above-mentioned glass plate, a transparent film for reducing the reflectance was formed on the other glass main surface on which the transparent conductive film was not formed as follows.

After masking the surface of the glass plate on which the transparent conductive film was formed, the glass plate was treated with 0.05 mol of boric acid and 0.008 mol of potassium fluoride at a concentration of 1.25 mol / l. It was immersed in a supersaturated aqueous solution of hydrosilicofluoric acid for 2 hours. Take out the glass plate further,
By removing the mask, washing and drying, a silicon oxide film was formed on the other glass main surface where the transparent conductive film was not formed. This film has a substantial refractive index of 1.
28 porous silicon oxide film with a thickness of 100 nm
Met.

Next, an amorphous silicon layer was formed on the surface of the plate on which the transparent conductive film was formed in the same manner as in Example 1.
Next, a zinc oxide layer was formed on the amorphous silicon layer by a known sputtering method. Further, an Al layer was formed thereon as a back electrode in the same manner as in Example 1 to produce a solar cell, and the same evaluation as in Example 1 was performed. The results were as shown in Table 1.

(Examples 6 and 7) In the same manner as in Example 1,
A transparent conductive film was formed by forming a tin oxide film, a silicon oxide film, and a tin oxide film having a thickness of about 750 nm in this order on the surface of the glass plate. Sheet glass with these coatings formed,
450mm x 450 in cutting process after slow cooling process
It was cut into a glass plate having a size of mm. Next, using the above-mentioned glass plate, a transparent film for reducing the reflectance was formed on the other glass main surface on which the transparent conductive film was not formed as follows.

First, a mixed oxide film of titanium oxide and silicon oxide was formed on a glass surface by a known sol-gel method, and a mixed oxide film of silicon oxide and tin oxide was formed thereon by a known sol-gel method. In Examples 6 and 7,
The refractive index was adjusted by changing the ratio of each oxide in each mixed oxide. That is, in a mixed oxide of titanium oxide and silicon oxide, the refractive index can be increased by increasing the proportion of titanium oxide. In a mixed oxide of silicon oxide and tin oxide, the refractive index can be reduced by increasing the proportion of silicon oxide.

Next, an amorphous silicon layer was formed on the surface of the plate on which the transparent conductive film was formed in the same manner as in Example 1.
Next, a zinc oxide layer was formed on the amorphous silicon layer by a known sputtering method. Further, an Al layer was formed thereon as a back electrode in the same manner as in Example 1 to produce a solar cell, and the same evaluation as in Example 1 was performed. The results were as shown in Table 1. Example 8 A transparent conductive film was formed in the same manner as in Example 1 by forming a tin oxide film, a silicon oxide film and a tin oxide film having a thickness of about 750 nm in this order on the surface of a glass plate. The sheet glass on which these coatings were formed was cut into glass plates having dimensions of 450 mm × 450 mm in a cutting step after a slow cooling step. Next, using the above-mentioned glass plate, a transparent film for reducing the reflectance was formed on the other glass main surface on which the transparent conductive film was not formed as follows.

First, a mixed oxide film of silicon oxide and tin oxide was formed on a glass surface by a known sol-gel method. A porous silicon oxide film was formed thereon in the same manner as in Example 5.

Next, an amorphous silicon layer is formed on the surface of the plate on which the transparent conductive film is formed in the same manner as in Example 1.
Next, a zinc oxide layer was formed on the amorphous silicon layer by a known sputtering method. Further, an Al layer was formed thereon as a back electrode in the same manner as in Example 1 to produce a solar cell, and the same evaluation as in Example 1 was performed. The results were as shown in Table 1.

Embodiment 9 In the same manner as in Embodiment 1, a tin oxide film, a silicon oxide film and a tin oxide film having a thickness of about 750 nm are formed in this order on the surface of a glass plate to form a transparent conductive film. did. The sheet glass on which these coatings are formed is 450 mm × 450 m
It was cut into glass plates of m dimensions. Next, using the above-mentioned glass plate, the surface of the other glass surface on which the transparent conductive film was not formed was subjected to a process of making the surface state uneven by sandblasting in order to obtain an antiglare effect.

Next, an amorphous silicon layer was formed on the surface of the plate on which the transparent conductive film was formed, in the same manner as in Example 1.
Next, a zinc oxide layer was formed on the amorphous silicon layer by a known sputtering method. Further, an Al layer was formed thereon as a back electrode in the same manner as in Example 1 to produce a solar cell, and the same evaluation as in Example 1 was performed. The results were as shown in Table 1.

Example 10 As in Example 9, an antiglare treatment was performed on the other glass main surface on which the transparent conductive film was not formed. A mixed oxide film was formed on the glass main surface subjected to the antiglare treatment by the sol-gel method in the same manner as in Example 6.

Next, an amorphous silicon layer was formed on the surface of the plate on which the transparent conductive film was formed in the same manner as in Example 1.
Next, a zinc oxide layer was formed on the amorphous silicon layer by a known sputtering method. Further, an Al layer was formed thereon as a back electrode in the same manner as in Example 1 to produce a solar cell, and the same evaluation as in Example 1 was performed. The results were as shown in Table 1.

(Comparative Example 1) A glass plate of the same dimensions and the same material as in Example 3 was used, and in the same manner, using a mixed gas such as vapor of monobutyltin trichloride to obtain a film thickness of about 750.
A film made of tin oxide having a thickness of nm was formed.

Next, an amorphous silicon solar cell was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. The results were as shown in Table 1.

[0066]

Table 1----------------------------------------------------------------------------------------------------------------------------------------------- Glare Refractive index / thickness (nm) Refractive index / thickness (nm) Reflectivity First layer Second layer First layer Second layer (%) ---------------------- −−−−−−−−−−−−−−−−−−−−−−− Example 1 1.90 / 35 1.46 / 15 − − − 8.44 ○ ○ Example 2 2.02 / 25 1.50 / 20 − − − 8.52 ○ ○ Example 3 2.19 / 25 1.68 / 20 − − − 9.25 ○ ○ Example 4 1.82 / 45 1.46 / 25 − − − 8.42 ○ ○ Example 5 1.90 / 40 1.48 / 20 1.28 / 100 − − 5.12 ○ ○ Example 6 1.90 / 25 1.48 / 10 1.79 / 130 1.50 / 80 − 6.58 ○ ○ Example 7 1.90 / 35 1.48 / 15 1.95 / 100 1.72 / 60 − 7.05 ○ ○ Example 8 1.90 / 40 1.50 / 20 1.64 / 170 1.28 / 100 − 4.88 ○ ○ Example 9 1.90 / 45 1.50 / 20 − − Yes 8.22 ○ ◎ Example 10 1.90 / 40 1.46 / 25 1.80 / 120 1.48 / 90 Yes 6.36 ○ ◎ −−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 1 − − − − − 12.29 × × −−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−− (Note) Meanings of words in Table 1 ・ First layer: transparent substrate side ・ ◎: None, ○: Almost none, ×: strong

In each of the examples, there is almost no interference color and almost no reflection glare. On the other hand, in the comparative example having no transparent interlayer film and no transparent coating film, very strong interference color and glare were recognized. Also, the reflectance of the comparative example is about 1.5 times to about 2.3 times higher than that of the example.

[0068]

According to the present invention as described above,
By forming a transparent intermediate film between the transparent substrate and the transparent conductive film, the average reflectance and the reflection interference color from the light incident side are reduced, and when the transparent film is formed on the light incident side of the transparent substrate, The reflectance of the entire visible light region on the incident side is reduced, and the glare of reflection from the light incident side is greatly reduced. When the solar cell, which is the photovoltaic element, is installed on the roof of a house, the conversion efficiency of the photovoltaic element is improved, reflected light pollution is reduced, and discomfort from reflected light can be reduced.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a substrate for a photovoltaic device according to the present invention.

FIG. 2 is a schematic view showing an arrangement of a film forming apparatus in a float glass manufacturing line for manufacturing a substrate for a photovoltaic element according to the present invention.

[Explanation of symbols]

Reference Signs List 1 glass substrate 2 film with refractive index of 1.7 to 2.5 (tin oxide film) 3 film with refractive index of 1.45 to 1.8 (silicon oxide film) 4 transparent conductive film (tin oxide film) 5 refractive index 1 .2 to 1.45 film (silicon oxide film) 11 Glass 12 Melting furnace 13 Float bath 14 Slow cooling unit 15 to 19 Film forming device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 31/04 H01L 31/04 F 31/042 R (72) Inventor Norimatsu Hodaka Michio, Chuo-ku, Osaka-shi, Osaka 3-5-11, Nippon Sheet Glass Co., Ltd. F-term (reference) 2E108 CC09 CC18 GG16 KK00 LL01 MM00 NN07 2E110 AA04 AB02 AB04 BA05 BA12 BB05 GA33W GB32W GB53W 4F100 AA20C AA28B AA28D AB11A AG12 BA10 BA01 BA01 BA10 JN01A JN01B JN01C JN01D JN01E JN06 JN18B JN18C JN18D JN30 YY00B YY00C YY00D 5F051 BA03 BA11 FA02 FA03 GA03 GA06 GA11 GA20 HA20

Claims (8)

[Claims] 1. A roof and an outer wall member in which a transparent conductive film, a photoelectric conversion element, and a back electrode are sequentially laminated on one main surface of a transparent substrate on a side opposite to a side on which light rays are incident,
A roof and an outer wall member, wherein a transparent intermediate film composed of at least two layers is formed between the transparent substrate and the transparent conductive film. 2. The refractive index and the film thickness of the transparent intermediate film are adjusted so that the average reflectance and the reflection interference color from the light incident side are reduced as compared with the case where the transparent intermediate film is not provided. The roof and outer wall member according to claim 1, characterized in that: 3. The roof and outer wall member according to claim 1, wherein at least one transparent coating is formed on the other main surface of the transparent substrate on which light rays are incident. 4. An average reflectance from a light incident side is reduced by adjusting the refractive index and the film thickness of the transparent film as compared with a case where the transparent film is not provided. 4. The roof and outer wall member according to 3. 5. The roof and outer wall member according to claim 3, wherein an anti-glare treatment is performed on a side of the transparent substrate on which light rays are incident so that incident light is irregularly reflected. 6. The transparent intermediate film having a thickness of 1.7 on the transparent substrate side.
A first transparent intermediate film having a refractive index of 2.5 to 2.5 nm and a film thickness of 5 to 50 nm, and a refractive index of 1.45 to 1.8 on the first transparent intermediate film;
The second transparent intermediate film having a film thickness of 0 nm, and a refractive index of the first transparent intermediate film is larger than a refractive index of the second transparent intermediate film. 3. The roof and outer wall member according to 1 or 2. 7. The method according to claim 7, wherein the transparent coating is substantially 1.2 to 1.
5. The roof and outer wall member according to claim 3, wherein the coating has a refractive index of 45 and a film thickness of 50 to 200 nm. 8. The transparent film, wherein the transparent film on the transparent substrate side has a refractive index of 1.6 to 2.0 and a thickness of 50 to 200 nm,
The transparent film formed thereon has a refractive index of 1.25 to 1.
8. The roof and outer wall member according to claim 3, which is a two-layer film having a thickness of 30 to 150 nm.