JP5853825B2 - Top sheet for photoelectric conversion device, photoelectric conversion device, mold, and top sheet manufacturing device for photoelectric conversion device - Google Patents

Description

  The present invention relates to a top sheet for a photoelectric conversion device, a photoelectric conversion device, a mold, and a top sheet manufacturing apparatus for a photoelectric conversion device.

  Solar cell modules as photoelectric conversion devices are generally known to use tempered glass that is excellent in terms of weather resistance, heat resistance, impact resistance, and transmittance as a light-transmitting substrate on the light incident surface. Yes (Patent Document 1). In addition, attempts have been made to reduce the number of solar cells by reducing the number of solar cells by using solar cells more efficiently by condensing, and to reduce the cost of the entire solar cell module. As a solar cell module that performs such light collection, a solar cell module in which a Fresnel lens using a flat plastic material or the like is disposed on a glass surface is known.

  This Fresnel lens is of an imaging type and can be provided so as to collect sunlight vertically incident on the lens surface onto the solar battery cell. However, since the incident direction of sunlight changes depending on the time zone and season of the day, it is necessary to make the solar cell module always follow the movement of the sun in order to focus on the solar cell by the full-lens lens. Providing such a mechanism for tracking the solar cell module and a device for controlling the tracking leads to an increase in cost, and it is difficult to reduce the cost of the entire solar cell system.

JP 2001-295437 A

  This invention is made | formed based on the above situations, and the subject of this invention exists in provision of the surface sheet for photoelectric conversion apparatuses which can improve the electric power generation efficiency of a photoelectric conversion apparatus easily and reliably. . Moreover, this invention exists in provision of the photoelectric conversion apparatus which can improve electric power generation efficiency easily and reliably. Furthermore, this invention exists in provision of the shaping | molding die which can manufacture the said surface sheet for photoelectric conversion apparatuses, and the surface sheet manufacturing apparatus for photoelectric conversion apparatuses.

The present invention has been made to solve the above problems, and the surface sheet for a photoelectric conversion device according to the present invention is:
A transparent substrate layer;
A plurality of taper-shaped transparent protrusions arranged in the form of dots on the surface side of the base material layer,
The bottom surface of the protrusion is a one-time symmetric or two-time symmetric shape,
The ratio of the height of the protrusion to the length in the minor axis direction of the bottom surface of the protrusion is 0.8 or more and 3 or less,
The circumference of the bottom surface is 50 μm or more and 10 cm or less.

  When the surface sheet for a photoelectric conversion device is disposed on the surface of the photoelectric conversion device, light incident from the surface side of the protrusion is guided to the base material layer side and emitted toward the photoelectric conversion device. Can do. In particular, in the surface sheet for a photoelectric conversion device, the shape of the bottom surface of the protrusion is symmetrical once or twice, and the plurality of protrusions are arranged in the form of scattered dots, so that the incident direction of the light beam changes. Even so, the change in the intensity of the light beam emitted toward the photoelectric conversion device is less than that of the conventional full-lens lens. Furthermore, since the peripheral length of the bottom surface of the protrusion is 50 μm or more and 10 cm or less, and the ratio of the height of the protrusion to the length of the bottom surface of the protrusion is 0.8 or more and 3 or less, the protrusion Has a sufficient size and height, the light beam is preferably incident on the protrusion. As described above, the top sheet for a photoelectric conversion device can accurately emit light toward the photoelectric conversion device even when a change occurs in the incident direction of the light beam, and the power generation efficiency of the photoelectric conversion device can be easily and It can certainly be improved.

  In the said surface sheet for photoelectric conversion apparatuses, it is preferable that the standup angle of the side surface which cross | intersects the said short axis of a projection part is 60 to 90 degree | times. When the rising angle of the side surface of the protrusion is within the above range, the light beam can accurately enter the protrusion, and the strength of the protrusion can be sufficient. When formed, mold release can be performed easily and reliably.

  In the case of adopting the above configuration, it is possible to provide the side surface so that the inclination angle becomes larger than the rising angle as the surface side increases, but the rising angle of the side surface intersecting the short axis of the protrusion is 65 degrees or more. In addition, it is preferable that the inclination angle of an arbitrary point on the side surface intersecting the short axis of the protrusion is not more than the rising angle. As a result, a stronger projection can be obtained, and mold release can be performed more easily and reliably when the projection is formed with a mold.

  In the surface sheet for a photoelectric conversion device, it is preferable that the outer periphery of the bottom surface is formed of a smooth line having no discontinuous points. Thereby, dirt etc. are hard to adhere near the bottom of a projection part, and when a projection part is formed with a forming die, a projection part can be easily and surely released.

  In the top sheet for a photoelectric conversion device, the bottom surface is perpendicular to the short axis and is opposed to each other with two straight portions (hereinafter, may be referred to as a long side portion), and is perpendicular to the major axis and is opposite to each other. It is possible to adopt a configuration having a substantially polygonal shape having two straight portions (hereinafter also referred to as short side portions). According to this configuration, the light beam can easily enter from the side surface on the long side portion side, and the incident light beam can be emitted toward the photoelectric conversion device.

  When the above configuration is adopted, it is possible to provide the projection in a pyramid shape having an apex, but it is preferable that the projection has a ridge line substantially parallel to the major axis of the bottom surface at the top. By setting it as the shape which has such a ridgeline, the area of the side surface by the side of the said long side part can be enlarged, and a light ray will enter easily by the side surface by the side of this long side part.

  In the said surface sheet for photoelectric conversion apparatuses, it is also possible to employ | adopt the structure whose said bottom face is substantially elliptical shape. According to this configuration, the light beam can easily enter from the side surface intersecting the minor axis, and the incident light beam can be emitted toward the photoelectric conversion device.

  When the bottom surface is substantially polygonal or elliptical as described above, the ratio of the major axis to the minor axis is preferably 2 or more and 1000 or less. This makes it easy for light rays to enter from the side surface intersecting the short axis, and to easily dispose a plurality of protrusions so that the power generation efficiency of the photoelectric conversion device is less affected by the incident direction of the light rays.

  When the bottom surface has a substantially polygonal shape or a substantially elliptical shape as described above, a configuration is adopted in which the short axis of the bottom surface of one of the protrusions is substantially parallel to the long axis of the bottom surface of another adjacent protrusion. It is possible. According to this configuration, the side surface that intersects the short axis is arranged in a substantially orthogonal direction between the one protrusion and the other protrusion, and the power generation efficiency of the photoelectric conversion device has more influence on the incident direction of the light beam. It is hard to receive.

  When the bottom surface has a substantially polygonal shape or a substantially elliptical shape as described above, a configuration is adopted in which the major axis of the bottom surface of one of the projecting portions and the major axis of the bottom surface of another projecting portion adjacent to each other are substantially parallel. It is possible. According to this configuration, the side surface that intersects the major axis is substantially parallel to one projection and the other projection, and light from the major axis direction is incident mainly from the side surface that intersects the major axis of the projection. It is emitted toward In addition, the side surface that intersects the short axis is substantially parallel to one protrusion and the other protrusion, and light rays from the short axis direction are mainly incident from the side surface that intersects the short axis of the protrusion and emitted toward the photoelectric conversion device. Is done. Here, since the side surface that intersects the short axis has a larger area than the side surface that intersects the long axis, the surface sheet for the photoelectric conversion device has light rays from the short axis direction compared to light rays from the long axis direction. Easy to enter. For this reason, it can be suitably used for a photoelectric conversion device installed in a place where there is little fluctuation in the incident direction of the light beam, that is, the minor axis direction of the protrusion is along the incident direction of the light beam that can contribute most to power generation. By arranging the surface sheet for a photoelectric conversion device on the surface of the photoelectric conversion device so as to be positioned, the power generation efficiency of the photoelectric conversion device can be increased.

  In the top sheet for the photoelectric conversion device, a configuration in which the longitudinal direction of the bottom surface is bent like a bow and the side of the bottom surface is substantially arc-shaped can be adopted. According to this configuration, it is possible to cope with a change in the incident direction of the light beam by the side surface rising from the arc-shaped side, and the light beam is always incident efficiently from this side surface, and the incident light beam is photoelectrically converted. The light can be emitted toward the apparatus.

  In the said photoelectric conversion apparatus surface sheet, it is preferable that the total area of the bottom face of the said several projection part is 1/3 or more of the total area of the surface of the said base material layer. Thereby, a projection part is fully arrange | positioned on the surface side of a base material layer, and can improve the electric power generation efficiency of a photoelectric conversion apparatus.

  In the surface sheet for a photoelectric conversion device, it is preferable that the top portion of the protruding portion has a curved shape. Thereby, even if another member etc. and the top part of a projection part contact, there is little possibility of damaging another member.

  In the surface sheet for a photoelectric conversion device, it is preferable that the base material layer and the protrusion are integrally formed. Thereby, there is little possibility that a projection part will inadvertently leave | separate from a base material layer, and the said surface sheet for photoelectric conversion apparatuses can be manufactured easily and reliably with a shaping | molding die.

  In the said surface sheet for photoelectric conversion apparatuses, it is preferable that the said base material layer and the said projection part contain the inorganic type material as a main component. Thereby, a transparent base material layer and a projection part can be formed easily and reliably. This inorganic material is preferably a silicone resin or glass. Thereby, a transparent base material layer and a projection part can be formed more easily and reliably.

  It is preferable that the said surface sheet for photoelectric conversion apparatuses is used as a protection sheet of a solar cell module. This improves the power generation efficiency as described above and protects the photoelectric conversion device.

  In addition, a photoelectric conversion device according to the present invention includes a photoelectric conversion unit that converts light energy into electricity, and a surface sheet for the photoelectric conversion device having the above-described configuration that is stacked on the light incident surface side of the photoelectric conversion unit. . Since the said photoelectric conversion apparatus is equipped with the said surface sheet for photoelectric conversion apparatuses of the structure as stated above, electric power generation efficiency is high.

Furthermore, the mold according to the present invention is:
A mold for producing a surface sheet for a photoelectric conversion device,
Having a plurality of recesses capable of forming protrusions of the surface sheet for a photoelectric conversion device;
The opening surface of the recess is a one-time symmetric or two-time symmetric shape,
The opening surface of the recess is a one-time symmetric or two-time symmetric shape,
The ratio of the height of the recess to the length in the minor axis direction of the opening surface is 0.8 or more and 3 or less,
The circumferential length of the opening surface is 50 μm or more and 10 cm or less.

  The said shaping | molding die can manufacture the said surface sheet for photoelectric conversion apparatuses which consists of an already described structure easily and reliably. That is, the protrusions of the surface sheet for a photoelectric conversion device manufactured by the mold have a bottom surface that is symmetrical once or twice, and the ratio of the height of the protrusions to the length of the bottom surface in the minor axis direction. Is 0.8 or more and 3 or less, and the circumference of the bottom surface is 50 μm or more and 10 cm or less. For this reason, in the surface sheet for photoelectric conversion devices molded by the molding die, the power generation efficiency of the photoelectric conversion device can be easily and reliably improved.

  In the said shaping | molding die, it is preferable to contain an inorganic material as a main component. Thereby, the said shaping | molding die can be manufactured easily and reliably.

  The manufacturing apparatus of the surface sheet for photoelectric conversion devices which concerns on this invention is equipped with the said shaping | molding die which consists of an above-described structure. Thereby, the surface sheet for photoelectric conversion apparatuses which has the said advantage can be manufactured easily and reliably.

  It is preferable that the manufacturing apparatus of the surface sheet for photoelectric conversion devices further includes a light imprint unit that performs light irradiation on the photocurable forming material of the surface sheet for photoelectric conversion devices filled in the concave portion. Thereby, a projection part can be easily and reliably formed by irradiating light with the light imprint part to the photocurable molding material with which the recessed part was filled.

  The “short axis” is an axis that passes through the center of gravity of the bottom surface of the protrusion and has the smallest diameter. “Long axis” means an axis orthogonal to the short axis. The “length in the minor axis direction” means the length (diameter) of the bottom surface in the minor axis. The “rising angle of the side surface in the short axis direction of the protrusion” means an angle at which the side surface of the protrusion rises to the surface side, specifically, the normal direction of the surface sheet for the photoelectric conversion device and the above In the cross-sectional shape of the protrusion in a plane including both the minor axis direction, it means an angle formed by the side surface with the plane direction of the surface sheet for photoelectric conversion device. The “tapered shape” of the protrusion means that the inclination angle (angle in the tangential direction) of an arbitrary point on the side surface of the protrusion is 90 degrees or less with respect to the planar direction of the surface sheet for the photoelectric conversion device. means.

  As described above, the surface sheet for a photoelectric conversion device according to the present invention can easily and reliably improve the power generation efficiency of the photoelectric conversion device. Moreover, the photoelectric conversion apparatus according to the present invention has high power generation efficiency. Furthermore, the manufacturing apparatus of the shaping | molding die concerning this invention and the surface sheet for photoelectric conversion apparatuses can manufacture the surface sheet for photoelectric conversion apparatuses which show | plays the said effect easily and reliably.

FIG. 1 is a schematic perspective view of a top sheet for a photoelectric conversion device according to the first embodiment of the present invention. FIG. 2 is a schematic plan view of a protrusion of the surface sheet for a photoelectric conversion device in FIG. FIG. 3 is a schematic front view of a protrusion of the top sheet for a photoelectric conversion device in FIG. 1. FIG. 4 is a schematic front view in which a main part of a protrusion of the surface sheet for a photoelectric conversion device in FIG. 1 is enlarged. FIG. 5 is a schematic plan view of the surface sheet for a photoelectric conversion device in FIG. 1. FIG. 6 is a schematic cross-sectional view of a photoelectric conversion device in which the top sheet for the photoelectric conversion device of FIG. 1 is used. FIG. 7 is a schematic cross-sectional view of a forming die used for forming the top sheet for the photoelectric conversion device of FIG. 1. FIG. 8 is a schematic plan view of an embodiment different from the surface sheet for a photoelectric conversion device shown in FIGS. 1 to 7. FIG. 9 is a schematic plan view of an embodiment different from the surface sheet for a photoelectric conversion device shown in FIGS. 1 to 8. FIG. 10 is a schematic plan view of an embodiment different from the surface sheet for a photoelectric conversion device shown in FIGS. 1 to 9. FIG. 11 is a schematic front view of a protrusion of an embodiment different from the top sheet for a photoelectric conversion device shown in FIGS. 1 to 10. FIG. 12 is a schematic front view of a protrusion of an embodiment different from the top sheet for a photoelectric conversion device shown in FIGS. 1 to 11. FIG. 13 is a schematic plan view of a protrusion of an embodiment different from the surface sheet for a photoelectric conversion device shown in FIGS. 1 to 12. FIG. 14 is a schematic plan view of a protrusion of an embodiment different from the top sheet for a photoelectric conversion device shown in FIGS. 1 to 13. FIG. 15 is a schematic plan view of a protrusion of an embodiment different from the top sheet for a photoelectric conversion device shown in FIGS. 1 to 14. FIG. 16 is a schematic plan view for explaining the arrangement pattern of the protrusions in FIG. 15. FIG. 17 is a schematic plan view for explaining the arrangement pattern of the protrusions of FIG. 15 different from FIG. FIG. 18 is a schematic plan view of an embodiment different from the surface sheet for a photoelectric conversion device shown in FIGS. 1 to 17. FIG. 19 is a table showing the results of performing the stain resistance test and the power generation performance test for Examples 1 to 8 and 11 and Comparative Examples 1 and 2. FIG. 20 is a table showing the results of performing the stain resistance test and the impact resistance test for Examples 8 to 10 and Comparative Examples 3 to 6.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Top sheet 1 for photoelectric conversion device>
1 is a protective sheet disposed on the surface of the solar cell module. The surface sheet 1 for a photoelectric conversion device in FIG. The surface sheet 1 has a transparent plate-like base material layer 2 and a plurality of transparent protrusions 3 arranged on the surface side of the base material layer 2. Specifically, in the topsheet 1, a plurality of protrusions 3 are arranged in the form of dots on the surface of a base material layer 2 having a surface view shape. In addition, the some protrusion part 3 is mutually arrange | positioned with a clearance gap, and the base material layer 2 has a substantially smooth plane part (site | part in which the protrusion part 3 is not formed) on the surface.

  The protrusion 3 has a substantially inverted triangular prism shape. The bottom surface of the protrusion 3 has a two-fold symmetrical shape. Note that the two-fold symmetry means a figure that overlaps the original figure at 180 degrees when the figure is rotated. As shown in FIG. 2, the bottom surface of the protrusion 3 has two linear portions (hereinafter sometimes referred to as long side portions 5) orthogonal to the short axis and facing each other, and two orthogonal portions facing the long axis and facing each other. It is formed in a substantially polygonal shape having a straight line portion (hereinafter also referred to as a short side portion 6), specifically, a substantially rectangular shape.

  The bottom surface of the protrusion 3 is provided with a circumference of 50 μm or more and 10 cm or less. Here, the ratio of the length L (long axis length) of the long side portion 5 to the length W (short axis length) of the short side portion 6 is set to 2 or more and 1000 or less. The bottom surface of the protrusion 3 is formed of a smooth line whose outer periphery does not have discontinuities. Specifically, a curved portion 7 that continuously connects the long side portion 5 and the short side portion 6 is provided between the long side portion 5 and the short side portion 6 (rectangular corner portion). .

  As for the projection part 3, the cross-sectional shape in the plane containing both the normal line direction of the said surface sheet 1 and a short axis direction is formed in the substantially triangular shape as shown in FIG. Specifically, this cross-sectional shape is a substantially isosceles triangle. The protrusion 3 has a height H that is not less than 0.8 times and not more than 3 times the length W in the minor axis direction.

  The protrusion 3 has four side surfaces 9 and 10 rising from the bottom surface to the surface side. Of these four side surfaces 9 and 10, the side surface 9 rising from the short side portion 6 of the bottom surface rises substantially perpendicular to the plane direction of the base material layer 2 and is formed in a substantially triangular shape. Further, the remaining two side surfaces 10 (side surfaces rising from the long side portion 5 of the bottom surface) are inclined so as to approach the other side surface as the surface side is formed, and are formed in a substantially rectangular shape. The angle of inclination of the two side surfaces 10 with respect to the surface direction of the base material layer 2 is substantially constant from the back surface to the surface, but is formed in a smooth curved surface having no discontinuities near the top 11 and the bottom. ing. This curved surface will be described later.

  As shown in FIGS. 1 and 2, the protruding portion 3 has a ridge 12 on the top 11 that is substantially parallel to the long axis. The ridgeline 12 is provided with substantially the same length as the major axis. Moreover, as shown in FIG. 3, the top part 11 of the protrusion part 3 is comprised from the smooth curved surface which does not have a discontinuous point, and specifically, the oblique sides of a substantially isosceles triangle are connected continuously. It is formed in a curved shape.

  As shown in FIGS. 3 and 4, the protrusion 3 has a curved skirt 13 that is continuous from the side surface 10 having a constant inclination angle to the surface of the base material layer 2. The skirt 13 is continuous from the side surface 10 of the protrusion 3, and is formed so that the inclination angle gradually decreases from the continuous portion with the side surface 10 toward the base material layer 2 side and continues to the surface of the base material layer 2. Has been. The skirt can also be formed between the side surface 9 rising vertically and the surface of the base material layer 2 (not shown). However, in the surface sheet 1, the skirt portion 13 is not an essential component, and the bottom surface of the protrusion 3 in the surface sheet 1 means a concept that does not include the skirt portion 13, and is indicated by a one-dot chain line in FIG. 4. As shown, the area surrounded by the virtual surface of the side surface of the protrusion 3 and the virtual surface of the base material layer 2 means the bottom surface of the protrusion 3.

  The side surface (side surface intersecting the short axis) rising from the long side portion 5 on the bottom surface of the protrusion 3 is formed so that the rising angle is 65 degrees or more and 90 degrees or less. In the surface sheet 1, the rising angle means an angle calculated without including the skirt 13, and as shown by a one-dot chain line in FIG. It means the angle α formed with the virtual surface of the layer 2. In addition, the inclination angle of the side surface is the same as the rising angle α in the present embodiment.

  The plurality of protrusions 3 are arranged in a dotted manner as described above, and the short axis of the bottom surface of one protrusion 3 and the short axis of the bottom surface of another adjacent protrusion 3 are substantially parallel. It is arranged to become. Specifically, as shown in FIG. 5, the short axes of the plurality of protrusions 3 are arranged so as to be parallel to each other. Moreover, the some projection part 3 consists of substantially the same shape, and is arrange | positioned in the alignment state front and rear, right and left (refer FIG.1 and FIG.5). That is, the plurality of protrusions 3 are arranged such that the long side portions 5 are arranged in a straight line and the short side portions 6 are also arranged in a straight line. In the present embodiment, the plurality of protrusions 3 are arranged such that each side 2a of the rectangular base layer 2 is substantially parallel to the major axis and the minor axis. In addition, it is also possible to change the design so that the plurality of protrusions 3 are arranged so as to be inclined at a certain angle with respect to each side 2a of the base material layer 2 (for example, inclined at 45 degrees).

  The plurality of protrusions 3 are provided such that the total area (plan view) of the bottom surface is 1/3 or more of the total area (plan view) of the surface of the base material layer 2. That is, the total area of the bottom surfaces of the plurality of protrusions 3 is provided more than twice the surface of the base material layer 2 exposed on the surface side without the protrusions 3 being formed.

  The protrusion 3 is formed integrally with the base material layer 2. Specifically, the base material layer 2 and the protrusion 3 are integrally molded by a mold having a hole corresponding to the protrusion 3.

  Although the formation material of the base material layer 2 and the protrusion part 3 of the said surface sheet 1 is not specifically limited, It is preferable that the base material layer 2 and the protrusion part 3 contain an inorganic type material as a main component. Examples of the inorganic material include a silicone resin or glass.

  As the silicone resin, those generally used can be used. Of these silicone resins, straight silicone resins and modified silicone resins are preferred. One type of these silicone resins may be selected, or two or more types may be used in combination. Here, “straight silicone resin” is a polymer (resin) in which a methyl group, a phenyl group, or a hydrogen atom is bonded to a polysiloxane skeleton as a substituent, and “modified silicone resin” is secondary to a straight silicone resin. Is a polymer that is functionalized by binding functional groups.

  Examples of the straight silicone resin include methyl silicone resin and methylphenyl silicone resin.

  Examples of the modified silicone resin include epoxy-modified silicone resin, epoxy-polyether-modified silicone resin, carbinol-modified silicone resin, methacryl-modified silicone resin, phenol-modified silicone resin, methylstyryl-modified silicone resin, acrylic-modified silicone resin, methyl Examples thereof include hydrogen silicone resins.

  Moreover, you may add antioxidant, a mold release agent, a coupling agent, an inorganic filler, etc. with respect to this silicone resin in the range which does not impair the characteristic.

  The silicone resin can be obtained using a known silane compound. Examples of the silane compound include methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltrit -Butoxysilane; ethyltrichlorosilane, ethyltribromosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltrit-butoxysilane; n-propyltrichlorosilane, n-propyltribromosilane, n- Propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltriisopropoxysilane, n-propyltri-t-butoxysilane; n-hexyltrichlorosilane, n-hexyltribromo Lan, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltriisopropoxysilane, n-hexyltrit-butoxysilane; n-decyltrichlorosilane, n-decyltribromosilane, n-decyltrimethoxy Silane, n-decyltriethoxysilane, n-decyltriisopropoxysilane, n-decyltrit-butoxysilane; n-octadecyltrichlorosilane, n-octadecyltribromosilane, n-octadecyltrimethoxysilane, n-octadecyltriethoxy Silane, n-octadecyltriisopropoxysilane, n-octadecyltri-t-butoxysilane; phenyltrichlorosilane, phenyltribromosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyl Ditrichloropropoxysilane, phenyltri-t-butoxysilane; dimethoxydiethoxysilane; dimethyldichlorosilane, dimethyldibromosilane, dimethyldimethoxysilane, dimethyldiethoxysilane; diphenyldichlorosilane, diphenyldibromosilane, diphenyldimethoxysilane, Diphenyldiethoxysilane; phenylmethyldichlorosilane, phenylmethyldibromosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane; trichlorohydrosilane, tribromohydrosilane, trimethoxyhydrosilane, triethoxyhydrosilane, triisopropoxyhydrosilane, trit -Butoxyhydrosilane; vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltri Ethoxysilane, vinyltriisopropoxysilane, vinyltri-t-butoxysilane; γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycid Xylpropyltriethoxysilane, gamma-glycidoxypropyltriisopropoxysilane, gamma-glycidoxypropyltri-t-butoxysilane; gamma-methacryloxypropylmethyldimethoxysilane, gamma-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, γ-methacryloxypropyltri-t-butoxysilane; Propylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropyltrit-butoxysilane; γ -Mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltriisopropoxysilane, γ-mercaptopropyltri-t-butoxysilane Β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane; and partial hydrolysates thereof; and The mixture can be used.

As the glass material, a known glass frit that melts at a predetermined temperature can be used. For example, PbO—B ₂ O ₃ —ZnO, CaO—Al ₂ O ₃ —SiO ₂ , ZnO—B ₂ O ₃ , ZnO—PbO—B ₂ O ₃ —SiO ₂ , PbO—SiO ₂ —B ₂ O ₃ , B ₂ O ₃ —PbO, SiO ₂ —ZnO—BaO, SiO ₂ —ZnO—MgO, SiO ₂ —ZnO—CaO, SiO ₂ —B ₂ O ₃ —MgO, SiO ₂ —B ₂ O ₃ —BaO, SiO _{2 -B 2 O 3 -CaO, SiO 2} -Al 2 O 3 -BaO, SiO 2 -Al 2 O 3 -MgO, SiO 2 -Al 2 O 3 -CaO, SiO 2 -B 2 O 3 -Al 2 O 3 _{, SiO 2 -B 2 O 3 -Na} 2 O 3, SiO 2 -B 2 O 3 -K 2 O, SiO 2 -B 2 O 3 -Li 2 O, SiO 2 -Na 2 O, SiO 2 -Li 2 _{O, SiO 2 -K 2 O,} SiO 2 -B 2 O 3 -SrO, SiO 2 -PbO-Na 2 O, SiO 2 -Pb _{-Li 2 O, SiO 2 -PbO-} K 2 O, SiO 2 -B 2 O 3, SiO 2 -PbO-CaO, SiO 2 -PbO-ZnO, a _{SiO 2 -B 2 O 3 -Bi 2} O 3 main Components can be used. Preferably, the main component is zinc borosilicate, lead borosilicate, or bismuth borosilicate. In order to further improve the adhesion, if necessary, bismuth oxide, manganese oxide, titanium oxide, zirconium oxide, barium oxide, beryllium oxide, cuprous oxide, tin oxide, molybdenum oxide, vanadium oxide, neodymium oxide, Metal fine powders such as cadmium oxide, iron oxide, lanthanum oxide, tungsten oxide, arsenic oxide, antimony oxide, germanium oxide, chromium oxide, lead trioxide, yttrium oxide, cerium oxide and tungsten can be added. The softening point of the glass frit is preferably 900 ° C. or lower and 300 ° C. or higher, more preferably 400 ° C. or higher and 800 ° C. or lower from the viewpoints of adhesion and sinterability, although it depends on the firing temperature. As the structure of the glass frit, crystalline, amorphous or mixed glass frit of the glass frit composition can be used.

  It is preferable that the refractive index of the said base material layer 2 and the projection part 3 is larger than the refractive index of air, and smaller than the refractive index of the translucent board | substrate of the surface side of a photoelectric conversion apparatus. Specifically, it is preferable that the refractive index of the base material layer 2 and the protrusion part 3 is 1.1 or more and 1.5 or less. Thereby, the light beam which permeate | transmits the said surface sheet 1 from the surface side of the said surface sheet 1 is easy to reach | attain to a photoelectric conversion apparatus exactly without reflecting. In addition, when the base material layer 2 and the projection part 3 are formed from different members and are integrally joined, it is preferable that the refractive index of the projection part 3 is smaller than the refractive index of the base material layer 2. Thereby, the reflection of the light beam at the interface between the protrusion 3 and the base material layer 2 hardly occurs.

  The total light transmittance of the surface sheet 1 is preferably 70% or more, more preferably 80% or more, and further preferably 90% or more. Thereby, there is little loss of a light ray and it can contribute by the improvement of the power generation efficiency of a photoelectric conversion apparatus. The total light transmittance is a value measured by a measurement method defined in JIS K 7361.

<Photoelectric conversion device>
The said surface sheet 1 is arrange | positioned and used for the surface side of the photoelectric conversion apparatus 20 (solar cell module), as shown in FIG. The solar cell module 20 includes a plurality of solar cells 21 (photoelectric conversion units), a transparent sealing material 22 that surrounds the solar cells, and a light transmission disposed on the surface side of the sealing material 22. And the surface sheet 1 disposed on the surface of the translucent substrate 23. The solar cell module 20 also includes a back surface protection plate 24 disposed on the back surface side of the sealing material 22.

<Mold 30 of the surface sheet 1>
Next, the mold 30 for producing the top sheet 1 will be described below with reference to FIG. The molding die 30 has a plurality of recesses 30 a that can form the protrusions 3 of the topsheet 1. The opening surface of the recess 30a is provided in correspondence with the shape of the bottom surface of the protrusion 3, the shape of the recess 30a is provided in correspondence with the shape of the protrusion 3, and the plurality of recesses 30a is an arrangement of the plurality of protrusions 3. It is arranged corresponding to.

  Various materials can be used for the mold 30, and for example, a metal such as nickel or the same kind of glass as the material for forming the surface sheet 1 described above can be used. The overall shape of the mold 30 may be a flat plate shape or a cylindrical shape.

<The manufacturing apparatus of the said surface sheet 1>
The manufacturing apparatus of the topsheet 1 is supplied by the forming mold 30 having the above configuration, a supply unit that supplies the photocurable mold forming material of the topsheet 1 to the recess 30a of the forming mold 30, and a supply unit. A photoimprinting part for irradiating light to the photocurable forming material of the recess 30a is provided.

<Method for Manufacturing Mold 30>
Various methods can be adopted as a method of manufacturing the mold 30, and for example, a method using photolithography can be adopted. This manufacturing method includes a step of exposing the resist surface in a state of being covered with a photomask having a predetermined pattern (arrangement pattern of protrusions), a step of developing the exposed resist, and forming on the surface of the developed resist. A method having a step of forming a mold by laminating mold forming materials can be employed. In this manufacturing method, exposure and development are performed so that the developed resist has the same shape as the protrusions 3 of the topsheet 1. In the step of forming the mold, for example, a method of electroforming a nickel layer on the surface of the resist and then removing the resist can be employed. In addition, the step of forming a mold is to create a laminate in which a photosensitive glass paste is applied to the resist surface, wind the laminate around a glass tube, and irradiate light from the inside of the glass tube to form a photosensitive glass. It is possible to employ a method of curing the paste and then removing the resist.

<The manufacturing method of the said surface sheet 1>
The topsheet 1 can be manufactured using the above-described mold 30. Specifically, the manufacturing method of the surface sheet 1 includes a step of supplying the surface sheet forming material to the mold 30, a step of curing the supplied surface sheet forming material, and a surface sheet obtained by curing. A step of releasing from the mold 30. When a photocurable material is used as the surface sheet forming material, light irradiation can be performed in the curing step.

<Advantages>
When the surface sheet 1 having the above-described configuration is disposed on the surface of the photoelectric conversion device 20, light rays incident from the surface side of the protrusion 3 are guided to the base material layer 2 side to solar cells 21 of the photoelectric conversion device 20. It can be made to emit toward. Since the protrusion 3 has a tapered shape and a refractive index higher than that of air, it can refract the incident light that is inclined with respect to the normal direction of the topsheet 1 so as to be close to the normal direction. It can be emitted as a light beam close to the vertical direction with respect to the solar battery cell 21. For this reason, the electric power generation efficiency of the photoelectric conversion apparatus 20 improves by using the said surface sheet 1. FIG.

  In the surface sheet 1, the shape of the bottom surface of the protrusion 3 is symmetrical twice, and the plurality of protrusions 3 are arranged in the form of scattered dots. Even if it changes, the change of the intensity | strength of the light ray emitted toward the photoelectric conversion apparatus 20 is small compared with the thing of the conventional Fullel lens. In particular, since the bottom surface of the protrusion 3 has a substantially rectangular shape, a light beam can easily enter from the side surface 10 on the long side portion side, and the incident light beam can be emitted toward the photoelectric conversion device. Furthermore, since the projection part 3 has the ridgeline 12 substantially parallel to the long axis of the bottom face, the area of the side face 10 on the long side part side is large, and light rays are more likely to enter.

  Since the ratio of the major axis to the minor axis of the bottom surface of the projecting portion 3 is 2 or more and 1000 or less, it is easy for light to enter from the side surface 10 and to easily arrange the plurality of projecting portions 3 accurately. That is, when the ratio of the major axis to the minor axis is less than the lower limit value, the major axis is short, the area of the side surface 10 is small, and the light beam may not easily enter the protrusion 3. On the other hand, if the ratio exceeds the upper limit, the protrusion 3 is too thin in plan view, and there is a risk that efficient arrangement of the plurality of protrusions 3 may be difficult, and further, from the side surface 11 that intersects the short axis. May not be able to be expected to be incident. The lower limit of the ratio of the major axis to the minor axis is preferably 2, more preferably 4, and even more preferably 6. In addition, the upper limit of the ratio of the major axis to the minor axis is preferably 1000, more preferably 100, and even more preferably 10.

  Since the major axis of the bottom surface of the plurality of protrusions 3 is arranged substantially in parallel, the side surface 10 that intersects the minor axis has a larger area than the side surface 11 that intersects the major axis, compared to the light rays from the major axis direction. Therefore, the surface sheet 1 is disposed so that the minor axis direction of the protrusion 3 is positioned along the incident direction of the light beam that can contribute most to power generation. Thus, the power generation efficiency of the photoelectric conversion device 20 can be increased.

  In the plurality of protrusions 3, the long side parts 5 are arranged in a straight line, and a groove along the long side part 5 is formed in the surface sheet 1 by the plurality of protrusion parts 3. Water tends to flow along the direction of the long side portion 5. Further, since the short side portions 6 are also arranged in a straight line, the water easily flows along the direction of the short side portions 6 as well.

  Since the total area of the bottom surfaces of the plurality of protrusions 3 is 1/3 or more of the total area of the surface of the base material layer 2, the protrusions 3 are sufficiently disposed on the surface side of the base material layer 2, and photoelectric conversion is performed. The power generation efficiency of the device can be increased. That is, if the total area of the bottom surface of the protrusion 3 is less than the lower limit, the existence ratio of the protrusion 3 is small, and there is a possibility that sufficient power generation efficiency cannot be improved. The ratio of the total area of the bottom surface of the protrusion 3 to the total area of the surface of the base material layer 2 is preferably 1/3 or more, more preferably 1/2 or more, and 2/3 or more. More preferably it is. On the other hand, the ratio of the total area of the bottom surface of the protrusion 3 to the total area of the surface of the base material layer 2 is preferably 19/20 or less, more preferably 9/10 or less, and 17/20 or less. More preferably it is. If the ratio of the total area of the bottom surfaces of the protrusions 3 exceeds the upper limit, it may be difficult to form the protrusions 3.

  Since the peripheral length of the bottom surface of the protrusion 3 is 50 μm or more and 10 cm or less and the ratio of the height of the protrusion to the length of the bottom surface of the protrusion 3 in the short axis direction is 0.8 or more and 3 or less, the protrusion 3 Since it has sufficient size and height, a light beam is suitably incident on the protrusion 3. That is, if the peripheral length and height of the bottom surface of the protrusion 3 are less than the lower limit value, it is difficult for light rays to enter the protrusion 3. On the other hand, if the height of the protrusion 3 exceeds the upper limit, the protrusion 3 becomes too high, and the strength of the protrusion 3 may be lacking. Moreover, when the circumference of a bottom face exceeds the said upper limit, there exists a possibility that suitable arrangement | positioning of the several projection part 3 may become difficult. Note that the lower limit value of the circumferential length of the bottom surface of the protrusion 3 is preferably 50 μm, more preferably 0.5 mm, and even more preferably 1 mm. Moreover, 10 cm is preferable, as for the upper limit of the peripheral length of the bottom face of the projection part 3, 5 cm is more preferable, and 2 cm is more preferable. Further, the lower limit value of the ratio of the height of the protrusion 3 is preferably 0.8, more preferably 1, and still more preferably 1.2. The upper limit of the ratio of the height of the protrusion 3 is preferably 3, more preferably 2.5, and even more preferably 2.

  Since the rising angle α of the side surface 10 of the protrusion 3 is 65 degrees or more and 90 degrees or less, the light beam can accurately enter the protrusion 3, the intensity of the protrusion 3 is sufficient, and the molding die 30 is used. The protrusion 3 can be easily formed. That is, when the rising angle α is less than the lower limit value, the protrusion 3 cannot obtain a sufficient height, and when trying to obtain a sufficient height, the inclination angle of the side surface 10 is set to be higher than the rising angle. However, since the shape needs to be increased and the shape becomes distorted, the strength may be lost and molding may be difficult. On the other hand, if the rising angle α exceeds the upper limit, the strength of the protrusion 3 is insufficient, the protrusion 3 may be inadvertently detached due to inadvertent contact or the like, and molding may be difficult. . The lower limit value of the rising angle α is preferably 60 degrees, more preferably 65 degrees, and further preferably 70 degrees. On the other hand, the upper limit value of the rising angle α is preferably 90 degrees, more preferably 85 degrees, and further preferably 80 degrees.

  The inclination angle of the side surface 10 of the protrusion 3 is the same as the rising angle α. That is, the inclination angle of an arbitrary point on the side surface 10 of the protrusion 3 is equal to or less than the rising angle α. The molding can be performed easily and reliably.

  Since the protrusion 3 is formed in a shape that does not have discontinuous points, dirt or the like is less likely to adhere thereto, and molding can be performed easily and reliably. That is, the bottom surface of the protrusion 3 has a curved portion 7, the outer periphery of the bottom surface is formed of a smooth line having no discontinuities, and the sleeve portion 13 is provided near the rising portion of the protrusion 3. The sleeve portion 13 continuously provides the side surface 10 of the projection portion 3 and the surface of the base material layer 2, and further, the top portion 11 is curved so that dirt and the like are not easily attached and molding is easy. And it can be done reliably. In particular, since the top portion 11 is provided in a curved shape, there is little possibility of damaging other members even if they are contacted by other members.

  When the base sheet 2 and the protrusions 3 are integrally molded, the surface sheet 1 is less likely to be inadvertently detached from the base material layer 2, and the surface sheet 1 can be easily and easily formed by molding. It can be manufactured reliably.

  Since the surface sheet 1 contains an inorganic material as a main component and specifically contains a silicone resin or glass as a main component, the transparent surface sheet 1 can be easily and reliably formed. .

  The surface sheet 1 is disposed on the surface side of the photoelectric conversion device 20 as described above, and improves the power generation efficiency as described above, and also functions as a protective sheet for the photoelectric conversion device 20. .

<Other embodiments>
The present invention can be carried out in various modifications and improvements in addition to the above embodiment. Hereinafter, although other embodiments of the present invention will be described, members having the same configurations as those of the first embodiment are denoted by the same reference numerals, and description thereof may be omitted.

  In the present invention, various arrangement patterns of the plurality of protrusions can be adopted. For example, in the surface sheet 31 shown in FIG. 8, the long sides 5 of the plurality of protrusions 3 are arranged in a straight line as in the surface sheet of the first embodiment, but the short sides 6 of the plurality of protrusions 3 are arranged. Are arranged so as to be stepped.

  The surface sheet 41 shown in FIG. 9 has adjacent protrusions 3 arranged in the orthogonal direction. That is, the short axis of the bottom surface of one projecting portion 3 and the major axis of the bottom surface of another projecting portion 3 adjacent thereto are arranged substantially in parallel. The surface sheet 41 shown in FIG. 9 has a side surface intersecting with the short axis arranged in a substantially orthogonal direction between one projecting portion 3 and another projecting portion 3, and the power generation efficiency of the photoelectric conversion device is that of light rays. Less susceptible to incident direction.

  The surface sheet 51 shown in FIG. 10 has a plurality of protrusions 3 arranged concentrically. That is, the plurality of protrusions 3 are arranged so that the major axis of each protrusion 3 is orthogonal to a virtual line connecting the center of gravity of the bottom surface of the protrusion 3 and the virtual center of the concentric circle. The plurality of projections 3 may be arranged radially around the virtual center, that is, the projections may be arranged so that the major axes coincide with each other in a virtual line connecting the virtual center and the projection. is there.

  In the present invention, the shape of the protrusion can be variously changed. For example, the protrusion 63 of the top sheet in FIG. 11 has a shape of an inverted semi-cylindrical shape. The protrusion 63 has a substantially semicircular cross-sectional shape on a plane including both the normal direction of the topsheet and the minor axis direction of the bottom surface of the protrusion 63. The protrusions 63 are provided so that the inclination angle gradually decreases from the rising angle toward the surface of the side surface. Note that the protrusions in FIG. 11 are also provided so as not to have discontinuities.

  The protrusion 73 of the topsheet shown in FIG. 12 has a quadrangular prism shape. The protrusion 73 has a substantially square cross-sectional shape on a plane including both the normal direction of the topsheet and the minor axis direction of the bottom surface of the protrusion 73. The protrusion 73 has a rising angle of 90 degrees and a side inclination angle of 90 degrees. Note that the protrusions in FIG. 12 are also provided so as not to have discontinuities.

  In the present invention, the shape of the bottom surface of the protrusion can be variously changed. For example, the protrusion 83 of the top sheet in FIG. 13 has a substantially octagonal bottom surface. The bottom surface of the projecting portion 83 is formed so that the outer periphery is a smooth curve and has no discontinuous points.

  As for the projection part 93 of the surface sheet of FIG. 14, the bottom face has a substantially elliptical shape. The bottom surface of the projecting portion 93 is formed so that the outer periphery is a smooth curve and does not have discontinuous points.

  The projection 103 of the top sheet in FIG. 15 is provided with a bottom surface in an arcuate shape. Specifically, the protrusion 103 has a curved bottom in the longitudinal direction, and the side of the bottom (side along the longitudinal direction) is formed in a substantially arc shape. In other words, both sides of the bottom surface of the projection 103 are formed in a circular arc shape that is bent in the same direction. The bottom surface of the protrusion 103 is formed so that the outer periphery is a smooth curve and does not have discontinuous points.

  The arrangement method of the protrusion 103 in FIG. 15 is not particularly limited, but can be arranged as shown in FIGS. 16 to 18, for example.

  In the surface sheet of FIG. 16, the plurality of protrusions 103 are arranged such that the inner surface 103a (the surface rising from the side bent on the longitudinal direction) faces in the same direction (for example, the lower side in the drawing). The protrusions 103 are arranged in a scale pattern as a whole.

  In the surface sheet of FIG. 17, the inner surface 103a of one protrusion 103 faces one side (for example, the lower side in the drawing), and the other surface adjacent to the side (for example, the lower side in the drawing) that the inner surface 103a of the one protrusion 103 faces. The inner surface 103a of the protrusion 103 is disposed so as to face the one protrusion 103 (for example, the upper side in the drawing). The protrusions 103 in FIG. 17 are arranged such that the protrusions 103 whose inner surfaces 103a face in different directions are shifted by about a half pitch in the longitudinal direction, and the plurality of protrusions 103 form a plurality of chain patterns as a whole. It is arranged.

  In addition, it is also possible to form a top sheet having a plurality of types of protrusions having different shapes by combining the plurality of types of protrusions described above. Moreover, it is also possible to combine a plurality of kinds of the above-described projection pattern arrangement patterns so that the topsheet includes a plurality of projection patterns. Specifically, as shown in FIG. 18, the protrusion 103 in FIG. 17 and the protrusion 3 in FIGS. 1 to 7 are formed on the topsheet. The top sheet of FIG. 18 has a disposition pattern (disposition pattern of protrusions on the left side of the drawing) in which the tips of the protrusions 3 in the shape of a bar in plan view are disposed toward the center of the inner surface 103a of the protrusion 103 curved in plan view. ) And a disposition pattern (arrangement pattern of protrusions on the right side of the drawing) in which the protrusions 3 having a substantially square shape in plan view are included so as to be included in the inner surface 103a of the protrusion 103 curved in plan view. ing.

  In the above embodiment, a method using a molding die is described as a method for forming the protrusion. However, the present invention is not limited to this, and the protrusion can also be directly formed using a photoresist or the like. Further, even when a mold is used, it is not limited to a resin that is cured by irradiating light to a photocurable resin. For example, a flowable thermoplastic resin is supplied to the mold and cooled. It is possible to change the design as appropriate.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

(Creation of mold forming sheet)
A negative dry film resist (HM-4075 manufactured by Hitachi Chemical Co., Ltd.) was exposed without peeling off the cover film and the base film. For this exposure, a photomask having a large number of through holes having a short side of 30 μm and a long side of 1 mm was used. The exposure was performed with 150 mJ / cm 2 of UV light using a high-pressure mercury lamp.

  The cover film is peeled off from the exposed negative-type dry film resist, and shower development is performed for 1 min using a 0.5 wt% aqueous sodium bicarbonate solution at a liquid temperature of 25 ° C. and a development pressure of 0.1 MPa. The exposed part was removed. Thus, a mold forming sheet having a plurality of inverted triangular prism-shaped protrusions having a bottom width of 50 μm and a height of 75 μm was prepared.

(Creation of nickel mold)
An electroless nickel plating layer having a thickness of 0.2 μm was formed on the surface of the mold forming sheet on which the protrusions were formed, and then nickel electroforming was performed using the nickel plating layer as an electrode until the thickness became 1 mm.

  The base film is peeled off from the obtained nickel mold, and residues such as resist are removed by baking at 500 ° C. for 1 hour in an air stream, and formed with nickel having a tapered groove with an opening diameter of 50 μm and a depth of 75 μm. A mold (hereinafter sometimes referred to as a nickel mold) was created.

(Creation of glass roll mold)
A photosensitive glass paste was applied to the surface of the mold forming sheet on which the protrusions were formed to a thickness of 0.5 mm and dried at 120 ° C. for 10 minutes to obtain a glass paste film. The glass paste film was wound so that the glass paste was in close contact with the glass tube. The glass paste was irradiated with ultraviolet rays by an ultraviolet light source in the glass tube. As this glass tube, a glass tube having a diameter of 10 cm having 20 ultraviolet LEDs (NC4U133A manufactured by Nichia Corporation) as an ultraviolet light source was used. This irradiation time was 10 min. The glass paste was cured by this ultraviolet irradiation, and then the mold forming sheet was peeled off. Thereafter, the glass tube is fired at 400 ° C. for 20 minutes and then at 630 ° C. for 20 minutes in an air stream to remove organic components and melt the glass frit, and on a taper having an opening width of 40 μm and a depth of 45 μm. A glass roll mold having grooves was created.

(Examples 1-5)
As Example 1, a surface sheet was prepared using the nickel mold. First, based on silyl hydride having a nickel type having a number average molecular weight of about 1850, poly (dimethylsiloxane) having vinyl groups at both ends thereof, 10 g, three Si—H groups, and a number average molecular weight of about 1200. Filling the groove pattern of the mold by applying a silicone composition in which 1.09 g of dimethylsiloxane, 0.27 g of platinum-divinyltetramethyldisiloxane complex (Pt in an amount of 0.054 mass%), and 28 mg of dimethyl maleate were applied. Further, a film was formed so that the total thickness of the silicone layer was 200 μm. Thereafter, this silicone layer was cured by heating for 5 minutes on a hot plate at 150 ° C., and the silicone layer was peeled off from the nickel mold. Thereby, a silicone rubber sheet (surface sheet of Example 1) on which a plurality of protrusions having a bottom width of 30 μm and a height of 35 μm were formed was obtained. In the surface sheet of Example 1, the arrangement of the plurality of protrusions was radial from the virtual center, and the occupied area (area ratio of the bottom surface of the protrusions to the total area of the surface of the base material layer) was 65%.

  Surface sheets (silicone rubber sheets) of Examples 2 to 7 were prepared by the same method as that of Example 1. In addition, the bottom face shape, size, arrangement, and occupied area of the protrusions in each example are as shown in the table of FIG. In addition, according to the shape and size of the protrusions, the photomask used for creating the above-described mold forming sheet was changed to create a mold forming sheet. In Example 7, two types of surface sheets having different protrusion shapes were prepared, and each surface sheet was cut in half so as to have the same sheet area, and the two types of cut surface sheets were cut into the solar cell module A. Used for pasting.

(Example 8)
As Example 8, a surface sheet was prepared using the nickel mold. 15 g of an alkali-soluble polymer in a nickel type (solid solution 50% propylene glycol monomethyl ether acetate solution of a copolymer consisting of 20 mol% methacrylic acid, 20 mol% benzene methacrylate, 45 mol% n-butyl methacrylate, 15 mol% 2-hydroxyethyl methacrylate), 2.26 g of trimethylolpropane PO-modified acrylate, dispersant: 0.45 g of Emulgen B-66 (manufactured by Kao Corporation), V-containing low melting point glass frit; 50 g of V35 (manufactured by Okamoto Glass Co., Ltd.), φ = 0.8 mm 150 g of zirconia beads were added, a glass paste dispersed with a bead mill; TSG-6U (manufactured by Imex Co., Ltd.) was applied, and dried in a 120 ° C. oven for 10 min to form a 300 μm thick glass paste layer on the mold. When this is fired and cooled in an air stream at 400 ° C. for 20 minutes and then at 630 ° C. for 20 minutes together with the mold, a square columnar (trapezoidal) protrusion having a bottom width of 50 μm and a height of 65 μm is formed on the surface. A glass plate having a total thickness of 170 μm (surface sheet of Example 8) was obtained. In addition, since the linear expansion coefficient of glass was about half that of the nickel mold, the glass plate could be easily released from the nickel mold as it was naturally cooled.

  A solar battery cell was formed on the top sheet of Example 8. Specific description will be given below. A zinc oxide film of 0.5 μm is formed on the back surface (surface on which no protrusion is formed) of the top sheet, J. et al. Appl. Phys. 24 (1985) p. Under the conditions described in 1607-1610, an amorphous silicon layer composed of an n-type silicon layer of 30 nm thickness / an i-type silicon layer of 1000 nm thickness / a p-type silicon layer of 50 nm thickness is formed, and 1 μm of aluminum is formed on the back surface thereof. Thus, solar cells were formed on the surface sheet. And the Sanei Kaken techni film VA760 was thermocompression bonded at 100 degreeC to the back surface of the surface sheet in which this photovoltaic cell was formed, and the a-Si solar cell module was obtained. In the surface sheet of Example 6, the arrangement of the plurality of protrusions was random and the occupation area was 40%.

Example 9
A silicone rubber sheet of Example 9 was prepared by the same method as that of Example 1. The shape, size, arrangement, and occupation ratio of the protrusions in Example 7 are as shown in the table of FIG. In addition, according to the shape of a projection part etc., the photomask used when producing the above-mentioned mold formation sheet was changed, and the mold formation sheet was created, respectively.

(Example 10)
Example 10 shows an example in which glass protrusions are directly formed. 34 g of alkali-soluble polymer (20% by mole of methacrylic acid, 20% by mole of benzene methacrylate, 45% by mole of n-butyl methacrylate, 50% solid content of propylene glycol monomethyl ether acetate solution of 15% by weight of 2-hydroxyethyl methacrylate), trimethylolpropane 2.26 g of PO-modified acrylate, 2.26 g of pentaerythritol pentaacrylate, photopolymerization initiator; Irgacure 819 (manufactured by Ciba Japan) 0.45 g, photosensitizer; DETX-S (manufactured by Nippon Kayaku Co., Ltd.) 0 .18 g, dispersant: 0.45 g of Emulgen B-66 (manufactured by Kao Corporation) was uniformly mixed to prepare an organic vehicle. V-containing low melting point glass frit: 45.3 g of V35 (manufactured by Okamoto Glass Co., Ltd.) and 150 g of zirconia beads having φ = 1.8 mm were added and dispersed with a bead mill; TSG-6U (manufactured by Imex Corporation). The dispersion condition is 1500 rpm for 30 minutes. After the dispersion treatment, zirconia beads were removed, and defoaming treatment was performed to obtain a photosensitive glass paste. On the glass substrate, the said photosensitive glass paste was apply | coated using the applicator. The coating film was dried at 120 ° C. for 20 minutes in a hot air oven to obtain a coating film having a thickness of 50 μm. This coating film was irradiated with 500 mJ / cm ² of UV light using a high-pressure mercury lamp through a photomask having a large number of through-holes having a short side of 30 μm and a long side of 1 mm. Using a 0.5 wt% aqueous sodium hydrogen carbonate solution, shower development was performed for 3 minutes under conditions of a liquid temperature of 35 ° C. and a development pressure of 0.15 MPa, and the unexposed portion of the coating film was removed. As a result, a plurality of square columnar protrusions having a bottom width of 50 μm and a height of 50 μm were formed. Thereafter, the glass substrate is baked in an air stream at 400 ° C. for 20 minutes and then at 630 ° C. for 20 minutes to remove organic components and melt the glass frit, and the surface sheet has an inverted triangular prism shape having a width of 33 μm and a height of 40 μm. (Example 10) was obtained. In the surface sheet of Example 10, the arrangement of the plurality of protrusions was random, and the occupation area was 70%.

(Example 11)
As Example 11, the surface sheet was created using the said glass roll shaping | molding die. Polymethyl methacrylate (molecular weight = 10000) 100 g, methyl methacrylate 300 g, photopolymerization initiator; Irgacure 819 (Ciba Japan Co., Ltd.) 5 g, photosensitizer; DETX-S (Nippon Kayaku Co., Ltd.) 3 g, γ -0.5 g of glycidoxypropyltrimethoxysilane was mixed to obtain a uniform solution (viscosity = 2000 mPa · s). This was photocured with a UV-LED lamp in the glass roll mold while being cast on a glass substrate at a speed of 6 cm / min using a glass roll mold, and then the glass substrate was released from the glass roll mold. . These steps are performed in series on a glass roll. Curing was completed by performing additional exposure of 1 J on the released glass substrate, and a surface sheet in which PMMA protrusions (width 40 μm, height 45 μm) aligned and protruded on the glass substrate was obtained. . In the surface sheet of Example 9, the plurality of protrusions were arranged in one direction, that is, an arrangement in which the long axes of the plurality of protrusions were provided in parallel, and the occupation area was 65%.

(Contamination resistance test and power generation performance test)
The surface sheets of Examples 1 to 8 and 11 were subjected to a stain resistance performance test and a power generation performance test. In the antifouling performance test, the ink was sprayed on the entire surface of each surface sheet, and then air-dried for 1 hour, and then the entire surface was sprayed with water for 1 hour and then dried. The light transmittance in this dried state was measured, and the difference from the light transmittance before the ink was sprayed was compared. When the transmittance difference was less than 2%, it was evaluated as ◯, when it was 2% or more and less than 10%, it was judged as Δ, and when it was 10% or more, it was marked as x. In addition, the power generation performance test was compared with the power generation amount of the solar cell module in which the surface sheet of each example was attached as a sheet sample to a commercially available solar cell module and the surface sheet was not attached. Here, as the sheet sample, the one that has been subjected to ink-jet spraying, air-drying, water spraying, and drying in the above-described anti-contamination performance test was used. In this power generation performance test, the total amount of power generated for one week was measured for the south direction, at an installation angle of 30 degrees (corresponding to a roof installation type). The total amount of power measured was compared with the sample data of the total amount of power of the solar cell module to which the surface sheet was not attached, and a value obtained by dividing the total amount of power measured by the sample data was calculated as a power generation index. That is, for example, if the measured total power is 300 Whr and the sample data is 270 Whr, the power generation index is 111.

  Further, the same contamination resistance performance test and power generation performance test were also performed on the surface sheets of Comparative Example 1 and Comparative Example 2. The top sheets of Comparative Example 1 and Comparative Example 2 are silicone rubber sheets prepared by the same method as the preparation method of Example 1. The protrusions of the topsheet of Comparative Example 1 were formed in an inverted semi-cylindrical shape with a bottom width of 150 μm and a bottom length of 2 mm and a height of 20 μm. The protrusions of the topsheet of Comparative Example 2 were formed in an inverted semi-cylindrical shape with a bottom width of 5 μm and a bottom length of 2 mm and a height of 2 μm.

  The results of the contamination resistance performance test and the power generation performance test are shown in the table of FIG. As is clear from this table, the top sheets of Examples 1 to 8 and 11 are superior to the top sheet of Comparative Example 2 in stain resistance, and have a high power generation index and improved power generation efficiency. I understand that.

(Impact resistance test)
An impact resistance test was performed on the top sheets of Examples 8 to 10. Here, the surface sheet of each example is attached to tempered glass (SUNMAX manufactured by Asahi Glass Co., Ltd.) used for the solar cell module, and a test for dropping a hard sphere as defined in JISB1501 from a height of 1 m is performed according to JISR3206. The results of examining the weight of the hard sphere when the glass breaks are shown in the table of FIG. In addition, the glass-made sheet | seat of Example 6 adhered to the said tempered glass through the adhesive agent, and evaluated.

  A similar test was performed for Comparative Examples 3-6. In Comparative Example 3, a prism sheet was attached to the surface of the tempered glass as a surface sheet. As this prism sheet, a prism sheet (Japan Special Optical Resin LP75-0.5; PMMA resin) having an apex angle of 40 degrees and a pitch of 0.5 mm was used. Moreover, the comparative examples 4-6 performed the test, without sticking a surface sheet on tempered glass. In Comparative Example 6, SOLITE manufactured by Asahi Glass Co., Ltd., whose surface was roughened, was used instead of SUNMAX manufactured by Asahi Glass Co., Ltd.

  According to this impact resistance test, it was found that sufficient strength was obtained even if the top sheets of Examples 8 to 10 were thin. That is, the solar cell module generally has a strength that results in an impact resistance test of around 200 g (see Comparative Examples 4 and 6), but when the thickness is reduced (eg around 1 mm). Is extremely reduced in strength (see Comparative Example 5). On the other hand, even if the surface sheets of Examples 8 to 10 have a thickness of about 1 mm, the impact resistance test yielded a result of 130 g or more, and sufficient strength was obtained.

  Moreover, when Examples 8-10 and Comparative Example 3 were subjected to the above-described contamination resistance test, it was found that Examples 8 to were excellent in contamination resistance and Comparative Example 3 was inferior in contamination resistance.

  The surface sheet of the present invention can be used optimally on the surface of a solar cell module installed outdoors, for example, because it can increase power generation efficiency by being attached to the surface of a photoelectric conversion device such as a solar cell module. .

DESCRIPTION OF SYMBOLS 1 Photoelectric conversion apparatus surface sheet 2 Base material layer 2a Each side 3 Projection part 3 Projection part 5 Long side part 6 Short side part 7 Curved part 9 Side face 10 Side face 11 Top part 12 Ridge line 13 Bottom part 20 Photoelectric conversion apparatus (solar cell module) )
21 Solar cell 22 Sealing material 23 Translucent substrate 24 Back surface protection plate 30 Mold 30a Recessed portion α Angle

Claims (14)

A transparent substrate layer;
And a plurality of transparency of projections arranged in a scattered pattern on the front surface side of the substrate layer,
The protrusion has a shape in which the side surface does not have discontinuous points, and the inclination angle of an arbitrary point on the side surface is 90 degrees or less with respect to the sheet plane direction,
The ratio of the height of the protrusion to the length in the minor axis direction of the bottom surface of the protrusion is 0.8 or more and 3 or less,
Ri 10cm der less circumferential length 50μm or more above the bottom,
The bottom surface has a substantially elliptical shape, or two straight portions orthogonal to the short axis and facing each other, and two straight portions orthogonal to the long axis and facing each other, and the diameter of the long axis of the bottom surface is the short axis A substantially polygonal shape larger than the diameter,
The top sheet for a photoelectric conversion device , wherein the short axis of the bottom surface of one of the protrusions is substantially parallel to the long axis of the bottom surface of another adjacent protrusion . The top sheet for a photoelectric conversion device according to claim 1, wherein a rising angle of a side surface intersecting the minor axis of the protrusion is 60 degrees or more . The rising angle of the side surface intersecting the short axis of the protrusion is 65 degrees or more,
The surface sheet for a photoelectric conversion device according to claim 2, wherein an inclination angle of an arbitrary point on a side surface intersecting the short axis of the protrusion is not more than the rising angle.   The top sheet for a photoelectric conversion device according to claim 1, wherein the outer periphery of the bottom surface is formed of a smooth line having no discontinuous points. The top sheet for a photoelectric conversion device according to any one of claims 1 to 4, wherein the protrusion has a ridge line substantially parallel to the major axis of the bottom surface at the top. The top sheet for a photoelectric conversion device according to any one of claims 1 to 5, wherein a ratio of the major axis to the minor axis is 2 or more and 1,000 or less. A transparent substrate layer;
A plurality of transparent protrusions arranged in the form of dots on the surface side of the base material layer;
With
The protrusion has a shape in which the side surface does not have discontinuous points, and the inclination angle of an arbitrary point on the side surface is 90 degrees or less with respect to the sheet plane direction,
The ratio of the height of the protrusion to the length in the minor axis direction of the bottom surface of the protrusion is 0.8 or more and 3 or less,
The circumference of the bottom surface is 50 μm or more and 10 cm or less,
Longitudinally bending the bow of the bottom surface, the bottom surface sides have a substantially arcuate shape der Ru for a photoelectric conversion device topsheet. The surface sheet for a photoelectric conversion device according to any one of claims 1 to 7 , wherein the total area of the bottom surfaces of the plurality of protrusions is 1/3 or more of the total area of the surface of the base material layer. The top sheet of the above-mentioned projection part is a curved surface shape, The top sheet for photoelectric conversion devices according to any one of claims 1 to 8 . The top sheet for a photoelectric conversion device according to any one of claims 1 to 9 , wherein the base material layer and the protrusion are integrally formed. The surface sheet for a photoelectric conversion device according to any one of claims 1 to 10 , wherein the base material layer and the protruding portion contain an inorganic material as a main component. The photoelectric conversion device for surface sheet according to claim 11 is the above inorganic materials Gaga lath. The surface sheet for a photoelectric conversion device according to any one of claims 1 to 12 , which is used as a protective sheet for a solar cell module. A photoelectric conversion unit that converts light energy into electricity;
A photoelectric conversion device comprising: the photoelectric conversion device top sheet according to any one of claims 1 to 13 , which is laminated on a light incident surface side of the photoelectric conversion unit.

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