JP5552699B2 - How to make a reflector - Google Patents

Description

  The present invention relates to a method for producing a reflector used in a concentrating solar cell.

Since the solar cell itself is still expensive, many concentrating solar cell systems have been proposed in order to reduce the overall cost of the solar cell system.
When the example is traced, as a thing using a Fresnel lens in a 1st example, patent document 1, patent document 2, and the 2nd example as a sheet-like condensing device, patent document 3, patent document 4, 3 In the example, Patent Document 5 and Patent Document 6 are used as the light guide, in Patent Example 7, the parabolic reflector is used in the fourth example, and in the fifth example, the flat or concave reflector is used in Patent Document 8. Patent Document 9, Patent Document 10, Patent Document 11, Patent Document 12, Patent Document 13, Patent Document 14, Patent Document 15, and Patent Document 16 can be found.
In the first example, in order to collect sunlight, a Fresnel lens having a large area is necessary, but it is expensive and not a good idea. The condensing device in the second example also has a complicated structure, and considering its manufacturing cost, it is inconvenient to contribute to the cost reduction of the system. In the third example, the light guide is often combined with a Fresnel lens, but it is inconvenient because the cost is high. In the examples using the fourth and fifth reflecting mirrors, there is a proposal for the arrangement of the reflecting mirrors, but no proposal for realizing a large reflecting mirror at a low cost is shown. In Patent Document 15, there is shown a plan for elastically deforming and bonding a thin flat glass mirror to a curved surface, but in order to deform it, a thin glass is necessary, and conversely, due to distortion due to unintended force. Since there is a high risk of breakage and distortion due to the non-uniformity of the adhesive occurs, there are actually disadvantages that are not desirable as commercial products. However, since it cannot be deformed when it is thick, it is difficult to achieve with glass.
In patent document 16, although the proposal which provided the reflecting mirror in the support body which has the curved support surface is proposed, in order to irradiate light from the support body side, the window hole for passing light is opened in the support body. This is a configuration in which a hole with a large area is necessary to apply light to the reflecting mirror, so that the peripheral frame around the hole becomes a curved support part, and the area of the support part can be made extremely small. Therefore, support along the curvature of the support surface is actually impossible, and in order to enable this, if the area of the support portion is increased, the window hole becomes relatively small and enters the reflector. The amount of light is reduced, resulting in a very inconvenient reflector.
As described above, even in reality, a reflector that is practically convenient has not been proposed.

JP 2003-258291 A JP2004-172256 JP2009-139418 JP2009-229581 JP2008-305879 JP2009-1117795A JP 06-316629 A JP 07-45854 JP 2008-198965 A JP 2001-298209 A JP 2006-269523 A JP 2006-86484 A JP 2009-295663 A JP2009-526386 JP 59-72401 JP-A-4-318501

SUMMARY OF THE INVENTION An object of the present invention is to overcome the above-mentioned problems and to provide a method for producing a reflector having a configuration that can be realized at low cost.

The method for producing a reflecting mirror of the present invention includes a flat plate that flexibly bends and has a restoring force by elasticity, and a curved body having a desired curved surface, and at least one of the surfaces of the flat plate is a mirror surface, This is a simple method for creating a reflector in which a face plate is arranged on the curved surface of the curved body, and is described in the following claims.

The invention according to claim 1 is a method for producing a reflecting mirror having a curved body having a desired curved surface, and is a flat plate having a predetermined length in a direction to give the desired curved surface and flexibly bending and having a restoring force by elasticity. Is inserted into a casing having a width shorter than the predetermined length, the plane plate is bent from the insertion, and a surface is filled with a filler on the side where the plane plate is convex at the center of the casing. By flattening and solidifying, a curved surface base is formed by a filler, and the curved flat plate is formed into a curved surface having a desired curved surface, and the curved surface is flexibly bent and elastically restored. Then, at least one surface is provided with a second flat plate that is a mirror surface and is made to follow the surface of the curved body so that the second flat plate has the same curvature as the curved body. It is characterized by that.

Since it is configured as described above, the reflecting mirror manufacturing method of the present invention can be configured easily and inexpensively and can collect light. Therefore, when applied to a solar cell system, the overall system cost can be reduced.

It is a figure explaining one embodiment of the reflective mirror by the creation method of the reflective mirror concerning the present invention. It is a figure which shows the embodiment of the detailed components structure of the reflective mirror by the production method of the reflective mirror which concerns on this invention. It is a figure which shows one embodiment of the curved body used for the reflective mirror by the preparation method of the reflective mirror which concerns on this invention. It is a figure which shows one embodiment of the production method of the reflective mirror which concerns on this invention. It is a figure which shows one embodiment of the solar cell system using the reflective mirror by the production method of the reflective mirror which concerns on this invention. It is a figure which shows another embodiment of the solar cell system using the reflective mirror by the production method of the reflective mirror which concerns on this invention.

A flat plate having a restoring force due to bending and elasticity; and a curved body having a desired curved surface, wherein at least one of the surfaces of the flat plate is a mirror surface, and the flat plate is disposed on the curved surface of the curved body A simple method of making a reflector is provided.
Hereinafter, description will be made using examples.

FIG. 1 is a diagram for explaining an embodiment of a reflecting mirror according to a reflecting mirror producing method according to the present invention. 1-A shows a concave mirror in a perspective state. In this example, it is a plane mirror in the depth direction and a concave mirror in the lateral direction. It has a curved surface body 101 having a curved surface giving a curved surface of a concave mirror, a mirror plate 102 made of a flexible film installed on this surface, and a housing 103 for supporting them. The mirror plate 102 has flexibility and thickness, such as a credit card, and has a transparent film such as transparent plastic or vinyl chloride coated with a metal such as aluminum on the installation surface side, or a mirror metal plate. Is applicable. By installing (attaching, etc.) the surface of the curved body 101 so as to contact the metal-coated surface side, the curved body 101 is bent along the curved surface to form a concave mirror. Although the mirror plate 102 is a flat plate, it is a concave mirror that follows the curved surface by being installed on the curved body 101. In addition, it is convenient to provide an ultraviolet ray preventing film for preventing the coating film from being deteriorated by ultraviolet rays and a cushioning shock absorbing film for preventing damage caused by wrinkles on the surface opposite to the metal coated surface side of the mirror plate 102. In the case where the mirror plate 102 is made of a flexible mirror surface metal plate, an ultraviolet protection film is not necessary.
R-r indicates a line segment connecting positions where the centers of curvature of the curved surfaces exist. Since it is a plane mirror in the depth direction, the center of curvature exists on this line segment. When the curved surface is a spherical surface, the focal point of the curved surface is at a distance of ½ of the radius from the center. Rays parallel to a line passing through the center of the sphere are bent to reflect and pass through the focal point. Similarly, the reflected light is also bent when the curved surface is an ellipse. 1-B shows a concave mirror having a curvature in the radial direction from the center. 1-C shows a concave mirror having curvature in the depth direction and the lateral direction.

FIG. 2 is a diagram showing an embodiment of a detailed component configuration of the reflecting mirror according to the reflecting mirror producing method according to the present invention. The essential components include a curved surface body 101 and a flexible flat mirror plate 102 which is attached to the curved surface and installed by screwing or the like. The curved surface 101 may be a curved plate as shown in 2-A, or may have a curved surface only on one side of the plate as shown in 2-B.
The casing 103 shown in 2-C is not particularly essential as long as it has a curved surface only on one side of the plate as shown in 2-B. A cross section of the mirror plate 102 taken along a broken line as in 2-D is shown in 2-E. The mirror plate 102 has a transparent film 201 such as a flexible plastic or vinyl chloride and a coating film 202 made of a metal such as aluminum on the back surface (upper stage). Those having a surface protection film 203 such as an ultraviolet ray prevention film to be prevented or a cushioning shock absorbing film for preventing damage caused by wrinkles (lower stage), and those having only a mirror metal plate without a transparent film can be used.

FIG. 3 is a diagram showing an embodiment of a curved body used for a reflecting mirror according to the method for creating a reflecting mirror according to the present invention.
In 3-B, the curved body 101 has a curved surface only on one side of the plate shown in 2-B of FIG. 2, and the housing 103 is unnecessary and has a simple form, but it is possible to make this over a large area. There are inconveniences that are not easy to make, such as cutting and plastic die cutting.
On the other hand, in 3-A, there is a housing 103, and the curved surface body 101 has an elastic plate 301 and a curved surface base 302 that bend by pressing force. At first glance, since the curved surface base 302 is the shape of the curved surface body 101 shown in 3-B, the 3-A one is more complicated than the 3-B one, but as shown in FIG. It does not mean that the elastic plate 301 is bent based on the table 302, but it is meaningful that the curved table 302 can be easily made based on the elastic plate 301. It is easy to give the elastic plate 301 a curved surface having a desired curvature. This is because, by fixing both ends at a certain distance and pushing the center downward, a curved surface can be obtained by the displacement (distance) fixed by pushing. In this way, the curved surface configuration is easy, and if the strength to the pressing force is desired thereafter, the curved surface table 302 may be made as shown in FIG.

FIG. 4 is a diagram showing an embodiment of a reflecting mirror producing method according to the present invention.
There is a housing 401 (4-A), and the distance L1 between both ends is a desired value. The walls at both ends are provided with grooves for fitting the both ends of the curved plate. In order to fasten both ends, a protrusion other than the groove may be used, and the groove is not particular. The elastic plate 301 (4-B) serving as a curved plate has a desired width L2 that is larger than the interval between both ends of the housing 401, and the elastic plate 301 has a desired width L2 due to the relationship between this width and the interval between both ends of the housing 401. When 301 is fitted (4-C), the elastic plate 301 obtains a bend with a predetermined curvature. In this state, the casing 401 is turned upside down and is 4-D. In 4-D, the curved surface has a convex center. Of course, it is also possible to attach the elastic plate 301 from the beginning with the casing 401 turned over.
In 4-E, the filler 402 to be solidified is filled until it reaches the surface of the housing 401 (4-F), and a lid 403 is placed on the surface (4-G). A commercially available filler can be used. After the filler 402 is solidified, the inverted state is 4-H. The elastic plate 301 forms a curved surface, and the curved surface base 302 formed by the base filler 402 firmly supports the elastic plate 301. When the elastic plate 301 itself has strength, the base curved base 302 is not necessarily required.
The filler 402 is preferably light in weight. Therefore, foamed polystyrene is one of the preferred materials coupled with its low cost. In 4-I, the mirror plate 102 divided into a plurality of sheets is stuck on the elastic plate 301. Of course, the mirror plate 102 may be one large one, but it is better to divide it into an appropriate size in consideration of workability. It is more convenient to unify the sizes. The mirror plate 102 is affixed to follow the curved surface of the elastic plate 301 to form a concave mirror. In this way, a large concave mirror can be created with a simpler technique than making a large concave mirror from the beginning.

As another method, after attaching an elastic plate 301 (4-B) (in this case, elasticity is not necessarily required) to the case 401, the case with a curved plate to which this is fixed is used as a mold. Prepare and fill the filler 402 in a state where the center of the curved surface is convex, flatten the surface, solidify, and then remove the housing with the curved plate to form the curved surface base 302 by the filler 402. Therefore, the mirror plate 102 divided into a plurality of sheets is stuck on the curved surface table 302. In this way, the housing with a curved plate can be used many times as a mold for solidifying the filler 402, which is advantageous.

FIG. 5 is a diagram showing an embodiment of a solar cell system using a reflecting mirror according to the method for creating a reflecting mirror according to the present invention.
In 5-B, the concave mirror 501 is installed so as to face the sunlight, and the solar cell 502 is arranged to receive the reflected light from the concave mirror 501 at a position away from the focal position F by a distance D. . The reduction ratio K (= L / W), which is the ratio between the size L of the concave mirror and the width W of the reflected light, is determined by the value of D. In order to estimate the aperture magnification K, the state of 5-B is planarized and shown in 5-A. In sunlight, incident light 503 enters the concave mirror 501 and exits as reflected light 504. Since the sunlight is incident in parallel to the line segment 505 passing through the center O of the curvature of the concave mirror 501, the reflected light 504 passes through the focal point F (at a distance 1/2 of the radius of curvature from the center O). Reflect as you do. Since the solar cell 502 is placed at a point separated from the focal point F by a distance D, the narrowed light enters the solar cell 502, and even the solar cell 502 having a small area generates power with light having an increased light density. Power generation efficiency can be increased. The distance D from the focal point, the angle α that the line segment connecting the end of the concave mirror and the focal point F becomes the incident light, the angle β that the line segment connecting the end of the concave mirror and the center O of the curved surface becomes the incident light, the radius of curvature R, the concave mirror 501 The relationship between the half arc length L and the solar cell width W can be calculated by the equation shown in 5-C. An example of the calculated result is shown in 5-D. For α45 °, β becomes 24.3 °, for R1m,
L is 0.42 m, K is 4 at D0.106 m, K is 5 at D0.085 m,
At D 0.042 m, K is 10, and the numerical values are in a proportional relationship. Therefore, when R is 2 m, all dimensions are doubled. For example, when K is 5, the portion 506 (at 5-B) that is the shadow of the solar cell is 1 time, so the reflected light cannot be obtained, so the reduction efficiency is 4 times that of 5-1 = 4. can get. In this arrangement, if the gradient of the reflector is set to the gradient of the roof, it can be made less susceptible to wind and snow.

FIG. 6 is a diagram showing another embodiment of the solar cell system using the reflecting mirror according to the reflecting mirror producing method according to the present invention.
A concave mirror 601 is installed substantially horizontally. Sunlight enters at an incident angle θ like the incident light 602, is reflected by the concave mirror 601, and travels in the direction of the reflected light 603. In the example of this figure, a concave mirror is used which has a flat surface in the direction in which sunlight travels and has a curvature in the width direction, as indicated by 1-A in FIG. Therefore, the light is condensed in the width direction so as to go to the focal point. The solar cell 604 is arranged in the vicinity of the focal length of the concave mirror 601 (in the spherical surface, a distance approximately half of the curvature) in the direction of the arrow 603 from the center of the concave mirror 601 so as to face the reflected light.
In such an arrangement, the surface of the solar cell faces downward and is not dusty. Moreover, since the back surface has a large inclination angle, there is the convenience that snow is not attached.

Since the reflected light is collected near the focal length, it can be collected on the solar cell 604 having a small area, and the cost of the solar cell 604 can be reduced. Since sunlight has only 1 kW of power per square meter, the concave mirror 601 having the required area is used to obtain the required energy even when the power generation efficiency is 15%. Considering the same area, the former can be made cheaper by comparing the price of the concave mirror, frame, small solar cell and its mounting shown in FIG. 4 with the price of a large solar cell system including the frame and mounting.
Needless to say, it is convenient to divide the solar cell 604 and the concave mirror 601 into a plurality of parts.
In FIG. 6, the frame on which the concave mirror 601 and the solar cell 604 are attached is not shown.

The concave mirror 601 can be tilted in the depth direction (the direction in which sunlight is incident and reflected) by an angle of several degrees from the horizontal. If it does in this way, dust can be effectively poured with rain water.
Since the concave mirror 601 may accumulate snow, a heating element may be attached to the surface for melting snow to prepare for a winter season in a region with a lot of snowfall.
As a countermeasure against strong winds, if the concave mirror 601 is attached substantially horizontally, it does not receive wind. In order to prevent the invasion of wind, it is convenient to attach a windshield skirt around the concave mirror 601 because the cold escapes along the skirt. In this arrangement, solar cell 604 receives wind blowing from south to north. Since the size of the solar cell 604 can be reduced, the wind force can be reduced, which is convenient.

As described above, the production method of the reflecting mirror according to the present invention is a very easy and inexpensive production method by producing a curved body of a concave mirror and installing a flexible sheet-like mirror on the curved surface. Since the solar cell system using this may be a solar cell having a smaller reduction rate than the solar cell alone, the solar cell cost can be reduced and the industrial utility is extremely high.

DESCRIPTION OF SYMBOLS 101 Curved body 102 Mirror plate 103,401 Housing 201 Transparent film 202 Cover film 203 Surface protective film 301 Elastic plate 302 Curved base 402 Filling material 403 Lid 501,601 Concave mirror 502,604 Solar cell 503,602 Incident light 504,603 reflection Light 505 Line segment 506 passing through center O The shaded part of the solar cell


that's all.

Claims (1)

In a method for producing a reflecting mirror having a curved body having a desired curved surface, a flat plate having a predetermined length in a direction giving a desired curved surface and flexibly bending and having a restoring force by elasticity is shorter than the predetermined length. The flat plate is bent from the fitting, and the flat plate is filled with a filling material on the side where the flat plate is convex at the center of the housing, and then solidified after the surface is flattened. A curved base made of a material is formed, and the curved flat plate is formed into a curved body having a desired curved surface, the surface of the curved body is flexibly bent and has a restoring force by elasticity, and at least one surface is a mirror surface Producing a reflecting mirror characterized in that a second flat plate is installed and is made to follow the surface of the curved body so that the second flat plate has the same curvature as the curved body. Method.

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