JP2004023012A - Optical junction structure of optical conductor and of photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical junction structure, minimizing the loss in the transmission of light to a photoreceptor from a light source, while easing the alignment accuracy of the photoreceptor and the optical conductor. <P>SOLUTION: In an optical junction structure comprising a bonding member 602 bonding an optical conductor 601 with a photoreceptor 603, an angle γ formed by a normal 604 on the side surface of a connecting member as viewed at an angle of 90°-β or larger to the lower end surface when viewed from the point (a) at the outer periphery of the lower end surface and a travelling direction 605 of the light is between 90° and 180°, when the angle of incidence of the light from the point (a) on the outer periphery of the lower end surface of the optical conductor 601 to the bonding member 602 is β. <P>COPYRIGHT: (C)2004,JPO

Description

【００９６】
表１に示すように、本発明による光接合構造を有するレシーバーを用いた実施例１、２の集光型太陽電池モジュールは、比較例１、２の集光型太陽電池モジュールに比べて変換効率が５〜１０％程度アップしており、本発明による光接合構造によれば光エネルギーの損失を小さく抑えることができることが証明された。
【００９７】
【発明の効果】
以上説明したように、本発明の光導体と受光体の光接合構造によれば、光源から受光体への光の伝達において損失を小さく抑えることができ、特に光起電力素子が受光体である太陽電池モジュールにおいて光の損失を小さく抑え、変換効率を高めることができる。
【００９８】
また、特に、接合部材として弾性を有するシート部材を用いた場合には、光導体と受光体の接合時に、光導体および受光体に何の損傷も与えず、且つ、接合部に気泡残り等を生じずに、本発明の接合部材の形状を容易に実現することが可能となる。
【図面の簡単な説明】
【図１】本発明の光接合構造の一例を模式的に示す斜視図である。
【図２】図１の光接合構造の上面図である。
【図３】図２のＡ−Ａ’における断面図である。
【図４】従来の光接合構造の例を模式的に示す斜視図である。
【図５】図４の光接合構造の上面図である。
【図６】図５のＡ−Ａ’における断面図である。
【図７】従来の光接合構造の別の例を模式的に示す斜視図である。
【図８】図７の光接合構造の上面図である。
【図９】図８のＡ−Ａ’における断面図である。
【図１０】従来の光接合構造の別の例を模式的に示す斜視図である。
【図１１】図１０の光接合構造の上面図である。
【図１２】図１１のＡ−Ａ’における断面図である。
【図１３】従来の光接合構造の別の例を模式的に示す斜視図である。
【図１４】図１１の光接合構造の上面図である。
【図１５】図１４のＡ−Ａ’における断面図である。
【図１６】本発明の光接合構造の一例を模式的に示す斜視図である。
【図１７】図１６の光接合構造の上面図である。
【図１８】図１７のＡ−Ａ’における断面図である。
【図１９】本発明の光接合構造を用いた実施例１のレシーバーを模式的に示す斜視図である。
【図２０】図１９のレシーバーの上面図である。
【図２１】図２０のＡ−Ａ’における断面図である。
【図２２】実施例１の集光型太陽電池モジュールの模式図である。
【図２３】実施例１の光接合構造における光の伝達を説明するための断面模式図である。
【図２４】本発明の光接合構造を用いた実施例２のレシーバーを模式的に示す斜視図である。
【図２５】図２４のレシーバーの上面図である。
【図２６】図２５のＡ−Ａ’における断面図である。
【図２７】実施例２の光接合構造における光の伝達を説明するための断面模式図である。
【図２８】比較例２のレシーバーを模式的に示す斜視図である。
【図２９】図２８のレシーバーの上面図である。
【図３０】図２９のＡ−Ａ’における断面図である。
【符号の説明】
１０１　光導体
１０２　接合部材
１０３　受光体
２０１　光導体
２０２　透明な接着剤
２０３　受光体
２０４　光
３０１　光導体
３０２　受光体
３０３　固定部材
３０４　光
４０１　光導体
４０２　光起電力素子
４０３　接合部材（充填材）
５０１　光導体
５０２　接合部材
５０３　受光体
５０４　光
６０１　光導体
６０２　接合部材
６０３　受光体
６０４　接続部材の側表面における法線
６０５　光の進行方向
７０１　太陽電池素子
７０２　基板
７０３　冷却部材
７０４　光導体
７０５　接合部材
７０６　光導体固定治具
７０７　接続部材の側表面における法線
７０８　光の進行方向
８０１　フレネルレンズ
８０２　筐体
８０３　光導体と受光体の光接合構造を持つレシーバー
９０１　太陽電池素子
９０２　基板
９０３　冷却部材
９０４　光導体
９０５　接合部材
９０６　光導体固定治具
９０７　接続部材の側表面における法線
９０８　光の進行方向
１００１　太陽電池素子
１００２　基板
１００３　冷却部材
１００４　光導体
１００５　接合部材
１００６　光導体固定治具[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a joint structure between a light guide and a photoreceptor. In particular, the present invention relates to a joint structure between a light guide and a photoconductor of a solar cell module using a solar cell element as a photoconductor.
[0002]
[Prior art]
At present, devices utilizing light are used in various places. For example, there are a device that controls an apparatus by obtaining an electric signal from a photoreceptor by light from a light source, and a device that obtains electric power by a photoreceptor, that is, a solar cell module. These devices often have a structure in which light from a light source is guided to a photoreceptor by a light guide or the like.
[0003]
An example of an optical junction structure between the light guide and the light receiving body is schematically shown in FIGS. FIG. 4 is a perspective view of the optical bonding structure, FIG. 5 is a view seen from the top of FIG. 4, and FIG. 6 is a cross-sectional view taken along line AA ′ of FIG. In this optical bonding structure, the light guide 201 and the photoreceptor 203 are directly bonded by a transparent adhesive 202, and light 204 (indicated by an arrow in FIG. 6) passes through the light guide and the adhesive. This is a structure in which light reaches the light receiving body. The light enters from the upper surface side of the light guide 201 and is guided to the light receiving body 203.
[0004]
Another example of the optical junction structure between the light guide and the photoreceptor is schematically shown in FIGS. FIG. 7 is a perspective view of the optical junction structure, FIG. 8 is a view as viewed from the top of FIG. 7, and FIG. 9 is a cross-sectional view taken along line AA ′ of FIG. In this optical bonding structure, each of the light guide 301 and the light receiving body 302 is mechanically fixed by a fixing member 303, and light 304 (indicated by an arrow in FIG. 9) passes through the light guide and the air. This is the structure that reaches the photoreceptor.
[0005]
In general, it is preferable that the light emitting surface of the light guide and the light receiving surface of the light receiving body have the same dimensions and shape to suppress loss of light energy transmission. However, in actuality, there are problems such as processing accuracy of the light guide and the light receiver, alignment accuracy of the light guide and the light receiver, and the like. If the dimensions and shape are the same, the light guide and the photoreceptor are shifted from each other due to positioning accuracy. As a result, transmission of light energy is lost.
[0006]
Therefore, in order to suppress such a loss of light energy, in advance, either the dimension of the light guide or the photoreceptor, the processing accuracy of the light guide and the photoreceptor, and the positioning precision of the light guide and the photoreceptor were expected. The dimensional shape is performed. The optical junction structure shown in FIGS. 4 and 7 is such that the size and shape of the photoreceptor are made larger in advance than the light exit surface of the light guide in consideration of the positioning accuracy.
[0007]
However, if the photoreceptor is a photovoltaic element, specifically, if it is a concentrating solar cell element, this alone does not solve the problem.
[0008]
For example, the optical junction structure shown in FIGS. 10 to 12 has the following problem. FIG. 10 is a perspective view of the optical bonding structure, FIG. 11 is a view seen from the top of FIG. 10, and FIG. 12 is a cross-sectional view taken along AA ′ of FIG.
[0009]
When the light exit surface of the light guide 401 is smaller than the light receiving surface of the photovoltaic element 402, a part where light is incident on the photovoltaic element is very weak, and the part hardly contributes to power generation. A useless portion is generated in the electromotive element. In this case, current concentration or the like may occur in a part of the photovoltaic element, and the internal structure of the photovoltaic element may be broken.
[0010]
In order to prevent this, it is conceivable to fill the space between the light emitting surface of the light guide 401 and the light receiving body 402 with the joining member 403. By providing the filler (joining member 403) between the photoreceptors, light emitted from the end face of the light guide can be confined in this portion.
[0011]
However, it has been found that significant transmission loss occurs in light energy depending on the shape of the side surface of the joining member. Such an example will be described with reference to FIGS. 13 is a perspective view of the optical bonding structure, FIG. 14 is a view from the top of FIG. 13, and FIG. 15 is a cross-sectional view taken along line AA ′ of FIG.
[0012]
When the light guide 501 and the light receiving body 503 are joined with the liquid adhesive 502, the structure of the joint between the light guide and the light receiving body may have a shape as shown in FIG. This is because the adhesive 502, which is a joining member, is excessive with respect to the distance between the light guide 501 and the light receiving body 503, so that the adhesive protrudes around the lower part of the light guide. In the case of such a shape, light 504 (indicated by an arrow in FIG. 15) from the light guide 501 leaks out of the joining member 502 and cannot reach the light receiving body 503.
[0013]
Conversely, if the adhesive is insufficient as shown in FIG. 6, the space between the light guide and the light receiving body cannot be filled, so that the light 204 does not enter the entire light receiving surface of the photovoltaic element. As a result, as in FIG. 12, there is a portion where the incidence of light is very weak on the photovoltaic element. Further, the light 204 leaks from the side portion because the side portion of the joining member rises. Therefore, light cannot be transmitted to the photoreceptor 203 properly.
[0014]
[Problems to be solved by the invention]
As described above, when light from a light source is guided to a photoreceptor using a light guide, transmission of light energy is lost at a joint between the light guide and the photoreceptor.
[0015]
In view of the above circumstances, a main object of the present invention is to provide an optical junction structure capable of minimizing loss in transmitting light from a light source to a photoreceptor while relaxing alignment accuracy between a photoreceptor and a light guide. .
[0016]
[Means for Solving the Problems]
The configuration of the present invention that achieves the above object is as follows.
[0017]
That is, the present invention provides a light guide that receives light at an upper end face and irradiates light from a lower end face, a light receiving body that receives light emitted from the light guide, and a joining member that joins the light guide and the light receiving body In the optical joining structure consisting of, when the incident angle of light to the joining member from the point a on the outer periphery of the lower end surface of the light guide is β, the lower end surface is viewed from the point a on the outer periphery of the lower end surface. On the other hand, an angle γ between a normal to the side surface of the connection member, which is seen at an angle of 90 ° −β or more, and the light traveling direction is 90 ° or more and 180 ° or less.
[0018]
In this case, the refractive index of the light guide is n _l Where α is the incident angle of light on the point a on the outer periphery of the lower end surface of the light guide, sin (90−α) = 1 / n _l It is preferable to satisfy the following. Accordingly, it is possible to minimize the leakage of light from the joining member that joins the light guide and the photoreceptor to the outside.
[0019]
The present invention also provides a light guide that receives light at an upper end face and irradiates light from a lower end face, a light receiving body that receives light emitted from the light guide, and a joining member that joins the light guide and the light receiving body. The optical joining structure is characterized in that the joining member has the same shape as the photoreceptor and is larger than the light guide.
[0020]
Further, the present invention provides a light guide that receives light at an upper end face and irradiates light from a lower end face, a light receiving body that receives light emitted from the light guide, and a joining member that joins the light guide and the light receiving body. In the optical bonding structure described above, the side surface of the bonding member is configured by a straight line connecting the outer circumference of the lower end surface of the light guide and the outer circumference of the light receiving surface of the light receiving body at the shortest distance.
[0021]
In these optical junction structures of the present invention,
"The joining member is made of an elastic sheet member",
"The photoreceptor comprises a solar cell element",
"The light received by the light guide is light obtained by condensing sunlight."
Is preferred.
[0022]
ADVANTAGE OF THE INVENTION According to this invention, loss in the transmission of light from a light source to a photoreceptor can be suppressed small. In particular, in a solar cell module in which a photovoltaic element is a photoreceptor, light loss can be suppressed and conversion efficiency can be increased.
[0023]
In addition, since the joining member is formed of an elastic sheet member, the joining between the light guide and the light receiving member does not cause any damage to the light guide and the light receiving member, and no bubbles remain in the joining portion. Thus, the shape of the joining member of the present invention can be easily realized.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
An example of the optical junction structure of the present invention is schematically shown in FIGS. FIG. 1 is a perspective view of the optical bonding structure, FIG. 2 is a view seen from the top of FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. In these figures, 101 is a light guide, 102 is a joining member, and 103 is a photoreceptor.
[0025]
Hereinafter, each component according to the present invention will be described in detail.
[0026]
(Light guide)
The light guide 101 of the present invention guides light to a light receiving body. Light received by the light guide and guided to the photoreceptor is direct light from a light source or light transmitted, refracted, reflected, or the like through some optical member. Examples of the light source include a laser, illumination, and the sun. The light transmitted, refracted, or reflected by any optical member includes light obtained by condensing the light from the light source by a lens or the like, light reflected by a reflecting mirror, and the like. The light is focused once immediately before the light incident surface of the light guide or in the light guide, and then is transmitted, refracted, reflected, etc. through the light guide and irradiated to the photoreceptor.
[0027]
In the present invention, known light guides can be used. Specifically, a light pipe or the like is used. It is preferable that these light guides can output the incident light with as little loss as possible. That is, when light is mainly transmitted through the light guide, the light guide is required to have high transmittance. The wavelength at which the transmittance needs to be high varies depending on the type of the photoreceptor. For example, when the photoreceptor is a solar cell element, the transmittance is preferably high at 300 nm to 1200 nm. The transmittance is preferably 95% or more, more preferably 98% or more.
[0028]
In addition, when light is transmitted while repeating reflection at the interface between the light guide and the outside or at the interface in the light guide, it is preferable that the total reflectance at the interface be high. In order to increase the total reflectance of the interface, it is necessary that the interface is as smooth and specular as possible. It is also important that dust and the like do not adhere to the interface. The total reflectance required in the present invention is preferably at least 99%, more preferably at least 99.9%.
[0029]
Examples of the light guide utilizing reflection include a light guide provided with a layer having a different refractive index on the outside. In the present invention, a light guide utilizing a difference in the refractive index between the light guide and air outside is preferable. This is because the difference between the refractive indices of the light guide and the outside air is very large, and thereby the angle of total reflection of the light incident into the light guide is widened. Therefore, the incident angle of the light incident on the incident surface of the light guide is broadened in the first place, so that more light can be used.
[0030]
In the present invention, as a material suitably used for the light guide, a material that can be used for so-called optical use is exemplified. For example, glass and resin materials can be used. Specific examples of the resin material include an acrylic resin, a polycarbonate resin, a polyester resin, a polyolefin resin, a norbornene-based resin, a silicone resin, and a fluororesin.
[0031]
When the transmitted light includes an infrared component, the material used for the light guide preferably has high heat resistance. Further, when the light intensity is high, it is preferable that the light resistance is high. For example, in applications where sunlight condensed several hundred times into a photoreceptor, excellent light resistance is required. When the above-mentioned resin material is used, light resistance can be improved by mixing an ultraviolet absorber, a light stabilizer, an antioxidant, and the like.
[0032]
Further, in order to increase the efficiency of light incidence and light emission, an anti-reflection treatment may be applied to the light receiving surface and the light emitting surface of the light guide. Especially when the refractive index of the light guide is large, these treatments are important. As a method for preventing reflection, a known method can be used. For example, a normal vapor deposition method, that is, vacuum vapor deposition, sputtering, ion plating, or the like can be used. Further, a resin film having a low refractive index may be provided. For example, coating with a fluororesin is performed. It is also possible to process the light incident surface of the light guide into a spherical shape.
[0033]
(Joining members)
The joining member 102 according to the present invention joins a light guide and a photoreceptor. The joining member of the present invention has any one of the following three characteristic forms.
{Circle around (1)} Assuming that the maximum incident angle of light on the joining member from the point a on the outer periphery of the lower end surface of the light guide is β, 90 ° with respect to the lower end surface as viewed from the point a on the outer periphery of the lower end surface. An angle γ between a normal line on the side surface of the connection member, which is seen at an angle of β or more, and the light traveling direction is 90 ° or more and 180 ° or less.
(2) It has the same shape as the photoreceptor and is larger than the light guide.
(3) The side surface is formed by a straight line connecting the outer periphery of the lower end surface of the light guide and the outer periphery of the light receiving surface of the photoreceptor at the shortest distance.
[0034]
By setting the shape of the joining member to any one of the above (1) to (3), even when light incident on the joining member reaches the side surface of the joining member, the light is guided toward the photoreceptor by reflection.
[0035]
The light path in the above mode (1) will be described with reference to FIGS. FIG. 16 is a perspective view of the optical junction structure, FIG. 17 is a view as viewed from above in FIG. 16, and FIG. 18 is a cross-sectional view taken along line AA ′ in FIG.
[0036]
Light incident on the light guide 601 is transmitted or reflected on the side surface of the light guide, and guided to the light receiving body 603. Among them, the light that reaches the point a on the outer periphery of the lower end surface of the light guide 601 enters the joining member 602, is reflected on the side surface of the joining member 602, and is guided to the light receiving body 603. The reflection of light on the side surface of the joining member 602 utilizes the difference in the refractive index between the joining member and air.
[0037]
Here, the refractive index of the light guide 601 is n _l , The refractive index of the joining member 602 is n _s If the incident angle of light to the point a on the outer periphery of the lower end surface of the light guide 601 is α, and the incident angle of light from the point a to the joining member 602 is β, β and α are n _l sinα = n _s There is a relationship of sinβ.
[0038]
The form of (1) is a side surface of the connecting member which is seen at an angle of 90 ° -β or more with respect to the lower end surface when viewed from a point a on the outer periphery of the lower end surface of the light guide 601, that is, as shown in FIG. The normal 604 on the side surface between the point b and the point c and the light traveling direction 605 (the light traveling direction is the connection direction between the light guide and the photoreceptor. And the vertical direction.) Is 90 ° or more and 180 ° or less. With such a configuration, even when the light incident on the bonding member 602 reaches the side surface of the bonding member, the light is reliably guided toward the light receiving body 603 by reflection. On the other hand, if γ is smaller than 90 °, the light that has reached the side surface of the joining member is transmitted to the outside, causing a loss of light energy.
[0039]
In the present invention, it is preferable that the joint member has low light loss similarly to the light guide. Further, in order to prevent reflection at the contact surface with the light guide, it is preferable that the refractive index of the joining member is close to the refractive index of the light guide. Refractive index n of joining member _s Is the refractive index n of the light guide _l For n _l −0.1 ≦ n _s ≤n _l +0.1, more preferably n _l −0.05 ≦ n _s ≤n _l +0.05. n _l Is 1.5, n _s Is about 0.3%, which is significantly smaller than the losses elsewhere.
[0040]
Furthermore, the joining member used in the present invention preferably has high transmittance, excellent heat resistance, and high light resistance, similarly to the light guide. As with the light guide, it is possible to mix an ultraviolet absorber, a light stabilizer, an antioxidant, and the like. Specific examples of the material include a silicone resin and a fluorine resin.
[0041]
These are applied and cured at the time of joining a light guide and a photoreceptor, such as an adhesive or an adhesive, and then molded into the shape of the present invention or an elastic sheet member previously molded into the shape of the present invention. It can be used. Particularly, in the present invention, a sheet member having elasticity is more preferably used.
[0042]
Hereinafter, a case where an adhesive or a pressure-sensitive adhesive is used for the joining member and a case where an elastic sheet member is used will be described.
[0043]
When an adhesive or a pressure-sensitive adhesive is used as a joining member to bond and fix the light guide and the photoreceptor, the shape of the adhesive is molded with a cutter or the like after the adhesive is cured. In the case of an adhesive, after the adhesion, the shape of the adhesive may be molded with a cutter or the like.
[0044]
When the adhesive strength between the light guide and the photoreceptor or the adhesive strength is insufficient, it is preferable to use an adhesion aid such as a silane coupling agent or to apply an easy adhesion treatment to the light guide or the photoreceptor. . When these are adhesives, it is preferable that by-products such as gas are not generated with curing. When gas or the like is generated, air bubbles remain in the joining member, and light transmission is hindered. In the case of using the moisture or the like in the air at the time of curing, when the bonding area is large, the moisture or the like does not sufficiently reach the center of the bonding surface, and care may be required because curing may occur.
[0045]
An elastic sheet member is very effective in implementing the shape of the joining member of the present invention. The shape of the present invention can be easily realized by molding the elastic sheet member into a desired shape in advance. If the sheet member having elasticity has no tackiness or adhesiveness, and the light guide and the photoreceptor cannot be fixed and used, the light guide and the photoreceptor may be mechanically fixed by other means. good. Care must be taken to ensure that the portion that holds the optical waveguide and the photoreceptor when they are mechanically fixed does not hinder the light transmitted and reflected in the optical waveguide.
[0046]
The elasticity of the sheet member having elasticity according to the present invention is such that the light guide and the photoreceptor are not damaged, cracked or chipped when attached to the light guide or the photoreceptor. Further, it is of such a degree that it follows irregularities on the surfaces of the light guide and the photoreceptor by elasticity. The joining member follows the surface of the light guide and the photoreceptor, thereby preventing a layer of air from being formed between the light guide and the photoreceptor and the elastic member, and suppressing loss of transmitted light energy. Becomes possible. Furthermore, it is possible to absorb expansion and contraction of the light guide and the photoreceptor due to heat, and it is possible to absorb these thermal expansions and contractions even when the light guide and the photoreceptor are mechanically fixed. .
[0047]
As a numerical value indicating a specific elasticity of the sheet member having such elasticity, there is a durometer of ASTM D2240. The hardness of the elastic sheet material suitably used in the present invention is a type 0020 or more and a type A 70 or less.
[0048]
Further, in the above mode (2), the fact that the joining member has the same shape as the photoreceptor means that the shape of the contact surface between the joining member and the photoreceptor is the same, and the dimensions are different to the extent that each includes a manufacturing error. Means There is no need to consider the thickness. For example, when the light receiving surface of the photoreceptor is a square of 12 mm square, the surface of the joining member in contact with the photoreceptor is a square of about 12 ± 3 mm square.
[0049]
In addition, the form of (3) is, for example, as shown in FIG. 27, along a line connecting the outer periphery of the lower end surface of the light guide 904 and the outermost periphery of the light receiving surface of the solar cell element (photoreceptor) 901 at the shortest distance. This is a form in which the joining member 905 is molded.
[0050]
(Photoreceptor)
The photoreceptor used in the present invention outputs an electric signal or electric power by receiving light. Specific examples include a solar cell element.
[0051]
Examples of the solar cell element suitably used in the present invention include a crystalline silicon type, a compound semiconductor type such as GaAs, CdTe, CdS, and CIS (CuInSe). The electrode for extracting the output of the solar cell element is preferably formed on the back surface of the solar cell element in order to eliminate the loss of incident light due to the shadow of the electrode. In order to effectively use incident light, it is preferable to form a texture structure on the surface of the photovoltaic element.
[0052]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.
[0053]
[Example 1]
In this example, receivers as shown in FIGS. 19 to 21 were prepared as concentrating solar cell modules for evaluation. FIG. 19 is a perspective view of the receiver, FIG. 20 is a view seen from above in FIG. 19, and FIG. 21 is a cross-sectional view taken along line AA ′ in FIG. In these figures, 701 is a solar cell element, 702 is a substrate, 703 is a cooling member, 704 is a light guide, 705 is a joining member, and 706 is a light guide fixing jig.
[0054]
First, a solar cell element 701, a substrate 702, a cooling member 703, a light conductor 704, a joining member 705, and a light conductor fixing jig 706 used as components of the receiver of this embodiment will be described.
[0055]
(Photovoltaic element)
As the solar cell element 701, a single-crystal silicon photovoltaic element (12 × 12 × 0.1 mm) was prepared.
[0056]
(substrate)
As the substrate 702, a substrate having a three-layer structure of copper / aluminum nitride / copper was prepared. The thickness of each layer is 0.3 / 0.635 / 0.25 mm.
[0057]
(Cooling member)
An aluminum heat sink was prepared as the cooling member 703.
[0058]
(Light guide)
A rod made of borosilicate glass (11 × 11 × 50 mm) was prepared as the light guide 704. The refractive index of this light guide 704 is n _l Is 1.458.
[0059]
(Joining members)
A 12 × 12 × 0.1 mm rectangular parallelepiped silicone resin sheet member was prepared as the joining member 705. Each surface has been smoothed, and the 12 × 0.1 mm surface is perpendicular to the 12 × 12 surface. Let the refractive index of this joining member 705 be n _s Is 1.403.
[0060]
(Light guide fixing jig)
A light guide fixing jig 706 having the structure shown in the figure was prepared.
[0061]
The above members were assembled by the following method.
[0062]
First, a solder paste was printed on a predetermined position on the substrate 702, and the photovoltaic element 701 was mounted on the predetermined position. These were heated in a reflow furnace and then cooled, and the substrate 702 and the photovoltaic element 701 were integrated.
[0063]
Next, a heat conductive adhesive (epoxy-based) is applied to a predetermined position of the cooling member 703, and is bonded to the substrate 702 and the integrated photovoltaic element 701. Heat cured.
[0064]
After the above operation was completed, electrical characteristics at 25 ° C. were measured using a simulator. The amount of light at the time of the measurement was equivalent to 250 times the sunlight.
[0065]
Finally, the joining member 705 was placed on the photovoltaic element 701, the light guide 704 was placed thereon, and the light guide was fixed by the light guide fixing jig 706.
[0066]
Subsequently, the obtained receiver was set in a light collecting system using a Fresnel lens shown in FIG. 22, and a solar cell module was assembled. At this time, all the direct light incident by the Fresnel lens 801 was once focused in the light guide 704, passed through the light guide 704 and the bonding member 405, and was incident on the photovoltaic element 701. The light collection magnification by the Fresnel lens was 250 times. In FIG. 8, reference numeral 802 denotes a housing, and 803 denotes a receiver to which a light guide is attached.
[0067]
The above condensing system and receiver were attached to a tracking device, and a concentrating solar cell module was assembled. Then, the obtained concentrating solar cell module was evaluated by the following method.
[0068]
(Measurement of conversion efficiency in outdoor exposure)
The solar cell module was installed outdoors, and the temperature of the photovoltaic element and the conversion efficiency of the solar cell module were measured there.
[0069]
The above measurement results were compared with the results previously measured using a simulator capable of measuring a single photovoltaic element at a constant temperature of 25 ° C. In addition, the measured value was subjected to temperature correction to a value at 25 ° C. The results are shown in Table 1 as relative values (%) with respect to the previously measured values of the simulator.
[0070]
FIG. 23 schematically shows an optical junction structure between a light guide and a photoreceptor in the concentrating solar cell module prepared in this example. In this embodiment, the incident angle α of the light to the point a on the outer periphery of the lower end surface of the light guide 704 is adjusted to 45 °. The incident angle β of the light from the point a to the joining member 705 is 47.3 °, and the connecting member seen from the point a at an angle of 90 ° −β or more with respect to the lower end surface of the light guide 704. The angle γ between the normal 707 on the side surface of 705 and the light traveling direction 708 is 90 °.
[0071]
[Example 2]
In this example, as the concentrating solar cell module for evaluation, a receiver as shown in FIGS. 24 to 26 was prepared in the same manner as in Example 1 except that the method of attaching the light guide was changed. 24 is a perspective view of the receiver, FIG. 25 is a view seen from above FIG. 24, and FIG. 26 is a cross-sectional view taken along line AA ′ of FIG. In these figures, 901 is a solar cell element, 902 is a substrate, 903 is a cooling member, 904 is a light guide, 905 is a joining member, and 906 is a light guide fixing jig.
[0072]
First, a solar cell element 901, a substrate 902, a cooling member 903, a light conductor 904, a joining member 905, and a light conductor fixing jig 906 used as components of the receiver of the present embodiment will be described.
[0073]
(Solar cell element)
The same one as in Example 1 was prepared.
[0074]
(substrate)
The same one as in Example 1 was prepared.
[0075]
(Cooling member)
The same one as in Example 1 was prepared.
[0076]
(Light guide)
The same one as in Example 1 was prepared.
[0077]
(Joining members)
A two-component addition-curable liquid silicone resin was prepared as the joining member 905. The above was mixed and defoamed for 5 minutes using a stirring and defoaming machine. Let the refractive index of this joining member 905 be n _s Is 1.403.
[0078]
(Light guide fixing jig)
The same one as in Example 1 was prepared.
[0079]
The above members were assembled by the following method.
[0080]
First, a solder paste was printed on a predetermined position on the substrate 902, and the photovoltaic element 901 was mounted on the predetermined position. These were heated in a reflow furnace and then cooled, and the substrate 902 and the photovoltaic element 901 were integrated.
[0081]
Next, a heat conductive adhesive (epoxy type) is applied to a predetermined position of the cooling member 903, and is bonded to a substrate 902 and a photovoltaic element 901 integrated with each other. Heat cured.
[0082]
After the above operation was completed, electrical characteristics at 25 ° C. were measured using a simulator. The amount of light at the time of the measurement was equivalent to 250 times the sunlight.
[0083]
Finally, the joining member 905 was dropped on the solar cell element 901, the light guide 904 was placed thereon, and the light guide was fixed by the light guide fixing jig 906. Thereafter, the bonding member 905 was defoamed in a vacuum desiccator. Further, the connection member 905 was placed in a hot air drying furnace and heated at 80 ° C. for 30 minutes to cure the connection member 905. Thereafter, the protruding side surface of the joining member 905 was cut and molded using a cutter knife along a line connecting the outer periphery of the lower end surface of the light guide 904 and the outermost periphery of the light receiving surface of the solar cell element 901 at the shortest distance.
[0084]
The obtained receiver was set in the same condensing system as in Example 1, and was installed in the same tracking device as in Example 1 to assemble a concentrating solar cell module. Then, the obtained concentrating solar cell module was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.
[0085]
FIG. 27 schematically shows an optical junction structure of a light guide and a photoreceptor in the concentrating solar cell module prepared in this example. In this embodiment, the incident angle α of the light to the point a on the outer periphery of the lower end surface of the light guide 904 is adjusted to 45 °. The incident angle β of the light from the point a to the joining member 905 is 47.3 °, and the connecting member seen from the point a at an angle of 90 ° −β or more with respect to the lower end surface of the light guide 904. The angle γ between the normal 907 on the side surface of the light source 905 and the light traveling direction 908 is 174.3 °.
[0086]
[Comparative Example 1]
A concentrating solar cell module was assembled in the same manner as in Example 1 except that no joining member was used. Then, the obtained concentrating solar cell module was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.
[0087]
[Comparative Example 2]
In this comparative example, as a concentrating solar cell module for evaluation, a receiver as shown in FIGS. 28 to 30 was prepared in the same manner as in Example 2 except that the step of molding the joining member using a cutter knife was omitted. . FIG. 28 is a perspective view of the receiver, FIG. 29 is a view seen from above in FIG. 28, and FIG. 30 is a cross-sectional view taken along line AA ′ of FIG. In these figures, 1001 is a solar cell element, 1002 is a substrate, 1003 is a cooling member, 1004 is a light guide, 1005 is a joining member, and 1006 is a light guide fixing jig, all of which are used in Example 2. The same thing was prepared.
[0088]
The above members were assembled by the following method.
[0089]
First, a solder paste was printed on a predetermined position on the substrate 1002, and the photovoltaic element 1001 was mounted on the predetermined position. These were heated in a reflow furnace and then cooled, and the substrate 1002 and the photovoltaic element 1001 were integrated.
[0090]
Next, a heat conductive adhesive (epoxy type) is applied to a predetermined position of the cooling member 1003, and is bonded to a substrate 1002 and a photovoltaic element 1001 which are integrated with each other. Heat cured.
[0091]
After the above operation was completed, electrical characteristics at 25 ° C. were measured using a simulator. The amount of light at the time of the measurement was equivalent to 250 times the sunlight.
[0092]
Finally, the joining member 1005 was dropped on the solar cell element 1001, the light guide 1004 was placed thereon, and the light guide was fixed by the light guide fixing jig 1006. Thereafter, the bonding member 1005 was defoamed in a vacuum desiccator. Further, the connection member 1005 was placed in a hot air drying furnace and heated at 80 ° C. for 30 minutes to cure the connection member 1005.
[0093]
The obtained receiver was set in the same condensing system as in Example 1, and was installed and installed in the same tracking device as in Example 1 to assemble a concentrating solar cell module. Then, the obtained concentrating solar cell module was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.
[0094]
Also in this comparative example, the incident angle α of the light to the point on the outer periphery of the lower end surface of the light guide is adjusted to 45 °, and the incident angle β of the light from the point a to the joining member is 47.3 °. The angle γ between the normal to the side surface of the connecting member, which is seen at an angle of 90 ° −β or more with respect to the lower end surface of the light guide when viewed from the point a, and the traveling direction of light is 90 °. The area of less than was widely present.
[0095]
[Table 1]

[0096]
As shown in Table 1, the concentrating solar cell modules of Examples 1 and 2 using the receiver having the optical junction structure according to the present invention have higher conversion efficiency than the concentrating solar cell modules of Comparative Examples 1 and 2. Is increased by about 5 to 10%, and it has been proved that the optical junction structure according to the present invention can suppress the loss of light energy.
[0097]
【The invention's effect】
As described above, according to the optical junction structure of the light guide and the photoreceptor of the present invention, it is possible to reduce the loss in transmitting light from the light source to the photoreceptor, and in particular, the photovoltaic element is the photoreceptor. In the solar cell module, light loss can be suppressed and conversion efficiency can be increased.
[0098]
In particular, when an elastic sheet member is used as the joining member, no damage is caused to the light guide and the photoreceptor at the time of joining the light guide and the photoreceptor, and air bubbles and the like remain at the joint. Without this, it is possible to easily realize the shape of the joining member of the present invention.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing one example of an optical junction structure of the present invention.
FIG. 2 is a top view of the optical junction structure of FIG.
FIG. 3 is a sectional view taken along line AA ′ of FIG. 2;
FIG. 4 is a perspective view schematically showing an example of a conventional optical junction structure.
FIG. 5 is a top view of the optical junction structure of FIG.
FIG. 6 is a sectional view taken along line AA ′ of FIG. 5;
FIG. 7 is a perspective view schematically showing another example of the conventional optical junction structure.
FIG. 8 is a top view of the optical junction structure of FIG. 7;
FIG. 9 is a sectional view taken along line AA ′ of FIG.
FIG. 10 is a perspective view schematically showing another example of the conventional optical junction structure.
11 is a top view of the optical junction structure of FIG.
FIG. 12 is a sectional view taken along line AA ′ of FIG. 11;
FIG. 13 is a perspective view schematically showing another example of the conventional optical junction structure.
FIG. 14 is a top view of the optical junction structure of FIG. 11;
FIG. 15 is a sectional view taken along line AA ′ of FIG.
FIG. 16 is a perspective view schematically showing one example of the optical junction structure of the present invention.
FIG. 17 is a top view of the optical junction structure of FIG. 16;
18 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 19 is a perspective view schematically showing a receiver of Example 1 using the optical junction structure of the present invention.
FIG. 20 is a top view of the receiver of FIG.
21 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 22 is a schematic diagram of the concentrating solar cell module of Example 1.
FIG. 23 is a schematic cross-sectional view for explaining light transmission in the optical junction structure of Example 1.
FIG. 24 is a perspective view schematically showing a receiver of Example 2 using the optical junction structure of the present invention.
FIG. 25 is a top view of the receiver of FIG. 24.
FIG. 26 is a sectional view taken along line AA ′ of FIG. 25.
FIG. 27 is a schematic cross-sectional view for explaining light transmission in the optical junction structure of Example 2.
FIG. 28 is a perspective view schematically showing a receiver of Comparative Example 2.
FIG. 29 is a top view of the receiver of FIG. 28.
30 is a sectional view taken along line AA ′ of FIG. 29.
[Explanation of symbols]
101 Light guide
102 joining members
103 photoreceptor
201 Light guide
202 Transparent adhesive
203 photoreceptor
204 light
301 light guide
302 photoreceptor
303 fixing member
304 light
401 light guide
402 Photovoltaic element
403 Joining member (filler)
501 light guide
502 joining members
503 photoreceptor
504 light
601 light guide
602 joining member
603 photoreceptor
604 normal on side surface of connecting member
605 Light traveling direction
701 Solar cell element
702 substrate
703 Cooling member
704 light guide
705 Joining member
706 Light guide fixing jig
707 Normal on the side surface of the connecting member
708 Light traveling direction
801 Fresnel lens
802 enclosure
803 Receiver with optical junction structure of light guide and photoreceptor
901 solar cell element
902 substrate
903 Cooling member
904 light guide
905 joining member
906 Light guide fixing jig
907 Normal on side surface of connecting member
908 Light traveling direction
1001 Solar cell element
1002 substrate
1003 Cooling member
1004 light guide
1005 Joining member
1006 Light guide fixing jig

Claims (7)

A light guide that receives light at an upper end face and irradiates light from a lower end face, a light receiving body that receives light irradiated from the light guide, and a bonding member that bonds the light guide and the light receiving body. ,
When the incident angle of light to the joining member from the point a on the outer periphery of the lower end surface of the light guide is β, 90 ° -β or more with respect to the lower end surface as viewed from the point a on the outer periphery of the lower end surface An angle γ formed between a normal to the side surface of the connecting member and a traveling direction of light, which is seen at a corner, is 90 ° or more and 180 ° or less. The refractive index of the light guide and n _l, the angle of incidence of the light on the a point on the lower end face the outer circumference of the light guide when the alpha, that satisfy sin (90-α) = 1 / n l The optical junction structure according to claim 1, wherein: A light guide that receives light at an upper end face and irradiates light from a lower end face, a light receiving body that receives light irradiated from the light guide, and a bonding member that bonds the light guide and the light receiving body. ,
The optical joining structure, wherein the joining member has the same shape as the light receiving body and is larger than the light guide. A light guide that receives light at an upper end face and irradiates light from a lower end face, a light receiving body that receives light irradiated from the light guide, and a bonding member that bonds the light guide and the light receiving body. ,
An optical joining structure, wherein a side surface of the joining member is formed by a straight line connecting an outer periphery of a lower end surface of the light guide and an outer periphery of a light receiving surface of the light receiving body at a shortest distance. The optical joining structure according to any one of claims 1 to 4, wherein the joining member is made of an elastic sheet member. The optical junction structure according to any one of claims 1 to 5, wherein the photoreceptor comprises a solar cell element. The optical junction structure according to claim 1, wherein the light received by the light guide is light obtained by condensing sunlight.

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