JPH11266032A - Condenser, heat collector, photo-detector having diffracting surface and photo-electric converter of artificial beams - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make feasible of simplifying the macroscopic structure of a condenser, by a method wherein the refractive index of a medium of a heat collector having a part thereof in contact with the medium is specified to exceed that of the outer part of photodetecting surface. SOLUTION: A cylindrical heat collector fitted to a photodetector of a condenser heats the water running in the cylinder by the energy of the condensed beams. Since a heat collector is used for the photodetectors 6, in order to prevent the heat from being externally radiated, a cover glass 11 and an adiabatic layer 10 using an air layer are provided on the surface while another insulating layer 23 made of urethane are provided on the backside. A diffracting surface 7 is formed by bonding a sheet in the structure holding an aluminum reflecting member between plastic made surface and backside protective material onto the backside of a plastic medium 5. In such a constitution, the condenser having multiple juxtaposed photodetectors in a simple structure can form a heat collecting module in high heat collecting efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light collecting device having a diffraction surface, a heat collecting device, a photodetector, and a device for photoelectrically converting artificial light.

[0002]

2. Description of the Related Art A light-receiving surface, a light-reflecting device installed so that at least a part thereof is located in a space surrounded by a regular reflection surface and the light-receiving surface and the regular reflection surface, and the space is filled. Examples of the structure of the light collecting device having a medium include:
"New Family 2-D nonimagin Concentrators The Compound Triangular Concentrator (New family 2-D nonimagin
g concentrators the compound triangular concentrat
or) ", APPLIED OPTIC
S), Vol. 24, No. 22 (1985), 3872
３８3876. In such a conventional structure, as shown in FIG. 23A, when the incident light 1 enters the light receiving surface 4 of the light condensing device and is reflected by the regular reflection surface 32 perpendicular to the incident light 2, the medium 5 is refracted. Regardless of the ratio, the reflected light 3 passes through the same optical path as the incident light 2 in the opposite direction and exits from the light receiving surface 4 to the outside.

In order to avoid this, for example, FIG.
As shown in (b), the specular reflection surface 32 is inclined with respect to the light receiving surface 4, and the light 2 incident on the light collector is reflected by the specular reflection surface 32 and is again incident on the light receiving surface 4 at an incident angle 33. To increase. In such a structure, by making the refractive index of the medium 5 larger than the refractive index outside the light receiving surface 4, total reflection can be performed on the light receiving surface. As described above, the incident light can be confined inside the light condensing device using the regular reflection on the inclined surface and the total reflection on the light receiving surface, and can be finally incident on the light receiving device 6. However, as shown in FIG. 23C, the incident angle 33 of the reflected light on the light receiving surface 4 cannot be made sufficiently large depending on the incident angle of the incident light 1, and the light escapes outside the light collecting device. .

[0004]

In the above prior art, since the regular reflection surface is used, the ratio of the area of the light receiving surface of the light receiving device to the area of the incident surface of the light collecting device, that is, the light collecting magnification is increased. In such cases, it is difficult to increase the light use efficiency.

An object of the present invention is to provide a technique capable of simplifying a macroscopic structure of a light collecting device.

Another object of the present invention is to provide a technique capable of increasing the light collection magnification while keeping the light use efficiency of the light collection device high.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0008]

The outline of a typical invention among the inventions disclosed in the present application will be briefly described as follows.

(1) A light-receiving surface, a diffraction surface, a medium filling a space between the light-receiving surface and the diffraction surface, and a light-receiving device in which at least a part of the surface is in contact with the medium. A light collecting device in which the refractive index of the medium is larger than the refractive index outside the light receiving surface.

(2) A heat collecting device wherein a light receiving surface, a diffractive surface, a medium filling a space between the light receiving surface and the diffractive surface, and at least a part of the surface contacting the medium,
The refractive index of the medium is larger than the refractive index outside the light receiving surface.

(3) A light receiving surface, a diffractive surface, a medium filling a space between the light receiving surface and the diffractive surface, and a photodetector (optical sensor) in which at least a part of the surface is in contact with the medium. Wherein the refractive index of the medium is larger than the refractive index outside the light receiving surface.

(4) A light-receiving surface, a diffraction surface, a medium filling a space between the light-receiving surface and the diffraction surface, and a device for photoelectrically converting artificial light at least a part of which is in contact with the medium. Wherein the refractive index of the medium is larger than the refractive index outside the light receiving surface.

(5) The diffraction surface is a reflection diffraction surface.

(6) The reflection diffraction surface is a blazed diffraction surface.

(7) The blazed diffraction surface has an asymmetric blaze angle.

(8) The blazed diffraction surface is arranged symmetrically on the left and right sides of the diffraction surface.

(9) A plurality of any one of the light collecting device, the heat collecting device, the light detector, and the light converting device for artificial light is modularized.

(10) In the above (9), the medium is continuously connected between any one of the plurality of light collecting devices, heat collecting devices, photodetectors, and artificial light light converting devices. I have.

According to the means, in the structure of the prior art, the light-collecting magnification can be increased by using a diffraction surface instead of a regular reflection surface.

[0020]

Embodiments of the present invention (embodiments) will be described below in detail with reference to the drawings.

According to an embodiment of the present invention, a light receiving surface, a diffraction surface, a medium filling a space between the light receiving surface and the diffraction surface, and a light receiving device in which at least a part of the surface is in contact with the medium , A heat collecting device, a photodetector, or a photoelectric conversion device for artificial light, wherein the refractive index of the medium is larger than the refractive index outside the light receiving surface.

The artificial light photoelectric conversion device uses artificial light such as a lamp, a laser, a light emitting diode, or a heat ray from an object heated to a high temperature as incident light, receives the light, and converts it into electric power. It is.

FIG. 1 is a sectional view showing a schematic configuration of a light collecting device according to an embodiment of the present invention.

In the light-collecting device of this embodiment, as in the structure having a cross section shown in FIG. 1A, in the light-collecting device using the diffraction surface 7, the light 2 incident on the diffraction surface has a positive surface. Rather than reflecting only in the reflection direction (0th-order light direction), the first-order, -1 according to the microscopic structure of the diffraction surface 7 and the wavelength of the incident light 1
Next, the light is reflected in the directions of secondary, secondary, etc. Therefore, even when the light is incident perpendicularly to the diffraction surface 7, the reflected light 3 does not all pass through the same optical path as the incident light 2, but the 0th order, 1st order,
The light is divided and reflected in respective directions such as -1st order, 2nd order, and -2nd order. Therefore, by designing an appropriate diffractive surface 7, the reflected light 3 is totally reflected inward on the light receiving surface 4 and can be efficiently taken into the light collecting device.

Similarly, as shown in FIG. 1B, when the light 1 is obliquely incident on the light receiving surface 4, the reflected light 3 is also reflected by the light receiving surface 4.
Can be designed to be totally reflected. FIG.
As shown in (c), even if the totally reflected light does not immediately enter the light receiving device 6, the light can be totally reflected again on the light receiving surface 4 and confined in the light collecting device.

In the above description, the energy distribution of the light of each order when the incident light 2 is diffracted is not mentioned, but the shape of the surface of the diffraction surface viewed microscopically is shown in FIG.
In the case shown in (1), the component of the light of the order having a direction close to the specular reflection direction with respect to the diffraction surface 7 macroscopically becomes large. Therefore, when the light receiving surface 4 and the diffraction surface 7 are arranged in parallel, a large light component is reflected in the specular reflection direction. A blazed diffraction surface having a symmetrical shape shown in FIG. 2C or an asymmetrical shape shown in FIG.

Naturally, these diffractive surfaces 7 are macroscopically flat or curved, and have a periodic triangular shape having a repetitive pitch 9 within a microscopic range of about the wavelength of the light to be handled. Has lattice grooves. Further, in order to keep the diffraction efficiency high, it is necessary to use diffracted light of order 10 or less at most.
Therefore, the repetition pitch 9 of the diffraction surface needs to be about 10 times or less the wavelength of light in the medium. Further, it is desirable to use the third or lower order diffracted light.

As shown in FIG. 3 (a), a light receiving device 6 having a rectangular parallelepiped cross section is provided between the light receiving surface 4 and the diffraction surface 7 as shown in FIG. The space surrounded by the surface 4 is the structure filled with the medium 5 and FIG.
As shown in FIG. 1, there is a structure in which a cylindrical or spherical light receiving device 6 having a circular cross section is installed between the light receiving surface 4 and the diffraction surface 7.

When the light receiving device 6 is a heat collecting device, a cover 11 is provided on the light condensing surface as shown in FIGS. The heat collection efficiency can be increased by inserting the heat insulating layer 10 such as air between them. Further, by providing the support 12 having heat insulating property outside the diffraction surface 7, heat insulating property and strength can be improved.

FIG. 5A shows an example having a reflection curved surface 13. In this case, the light receiving device 6 having a rectangular parallelepiped cross section is installed on the light receiving surface side in parallel with the light receiving surface. The light reflected by the diffraction surface 7 enters the light receiving device 6 directly or by being reflected by the reflection curved surface 13. In such a shape, the reflection curved surface 13
May be a regular reflection surface, but if it is a diffraction surface, the light can be collected more effectively. In addition, as shown in FIG. 5B, the light-collecting efficiency can be increased by arranging the diffraction surface 7 at an angle to the light-receiving surface 4.

FIG. 6A shows a structure in which an inclined diffraction surface 7 is arranged below the flat light receiving surface 4, and the direction 14 of the grating grooves of the diffraction surface is formed in a direction perpendicular to the inclination direction. In this structure, the surface 8 of the diffraction surface 7 has a microscopic cross section as shown in FIG. FIG. 6B shows a structure in which an inclined light receiving surface 4 is arranged above a flat diffraction surface 7. Thus, a high light-collecting efficiency can be obtained with a light-collecting device having a two-dimensional structure. Further, as shown in FIGS. 7A and 7B, by forming a diffraction groove in a direction along the slope, the light collecting effect by the prism structure constituted by the light receiving surface 4 and the slope 7 is obtained.
A structure having a light collecting effect by diffraction can be obtained. In this structure, the surface 8 of the diffraction surface 7 is microscopically shown in FIG.
It has a cross section as shown in FIG. In these structures shown in FIGS. 6 and 7, the light receiving device 6 has a plate shape, but may have a cylindrical shape as shown in FIG. 8, or a sphere, a rectangular parallelepiped, or the like. Needless to say, these surfaces may have a secondary structure such as unevenness.

FIG. 9 shows a microscopic structure of the diffraction surface. In the case of a symmetrical configuration as in the structure of FIG. 9, the light incident on the right side 15 from the center is
And the light incident on the left side 16 from the center is the light receiving device 6 on the left side.
The light collection efficiency can be increased by entering the light.
For this purpose, it is desirable that the microscopic shape of the diffraction surface 8 be a shape in which individual asymmetric triangular shapes are symmetrically arranged on the left and right as shown in FIG. Also in the structure as shown in FIG. 10, it is desirable to change the microscopic shape of the diffraction surface 8 from the center to the right and left sides of the device. In addition, as shown in FIG. 11A, when the diffraction groove is formed in a direction along the slope, FIG.
As shown in (A) AA ′ cross-sectional shape), the blaze angle at which the diffracted light is guided to the light receiving device 6 more effectively by changing the microscopic cross-sectional shape of the diffraction groove on the left and right of the center of the device. desirable.

FIG. 12 shows a structure in which the diffraction surface 7 has a wavy shape. In this case, the diffraction grooves 1 extend in the direction along the slope of the diffraction surface 7.
4 is desirable. Also, the light receiving device 6 is shown in FIG.
It may be installed in a direction along the wave shape of the diffraction surface 7 as in (a), or may be installed in a direction perpendicular to the direction as shown in FIG. Further, it may be installed in a direction between them. FIGS. 13A and 13B show a structure in which the cross section of the light receiving surface 4 is curved. As described above, the light receiving surface 4 of the light collector does not necessarily have to be flat. Further, the diffraction surface 7 may have a cross-sectional shape as shown in FIGS. A two-dimensional structure obtained by extending these structures in the front-rear direction of the drawing, or a light condensing device having a structure rotated around the rotation axis 30 is also conceivable. In these, the direction 14 of the diffraction groove may be a direction along the cross section of the diffraction surface 7 or a direction along the circumferential direction.

FIGS. 14A and 14B show examples in which diffraction grooves are two-dimensionally arranged when the diffraction surface is viewed from above. By arranging in this manner, light can be collected not only from the side surface of the light receiving device 6 but also from the periphery thereof toward the light receiving device 6, so that the light collection magnification can be increased. Further, as shown in FIG. 15, a large-area light-collecting module can be formed by modularizing a plurality of light-collecting devices. In addition, as shown in FIG. 16, by using a two-dimensional diffraction grating in which diffraction grooves 14 extending in different directions are combined, light incident around the light receiving device 6 can be effectively collected two-dimensionally.

FIG. 17 shows a sectional structure of the diffraction surface. In the simplest case, as shown in FIG. 17A, there is a structure having a desired microscopic unevenness on the diffraction surface side of the medium 5 and a reflective material layer 17 made of metal or the like on this surface. FIG.
As shown in (b), the back surface protective layer 18 is formed on the back surface of the reflective material layer 17.
Or a reflective material layer 17 as shown in FIG.
There is a structure in which a desired intermediate layer 19 is provided between the medium 5 and the diffraction surface side. This intermediate layer 19 is formed by applying the reflective material layer 17 to the medium 5.
May be used as an adhesive for adhering to the reflective material layer 17, a protective material for the reflective material layer 17, and an intermediate layer having a desired refractive index for increasing the reflectance of the reflective material layer 17. FIG.
(D) shows a case where the back surface of the medium 5 is microscopically flat and the intermediate layer 19 is flat on the medium 5 side. FIG. 17E shows a structure having an adhesive layer 20 between the intermediate layer 19 and the medium 5. Furthermore, it goes without saying that the same light-collecting effect as described above can be obtained even in a structure in which an adhesive layer for bonding each layer to the structure or a protective material layer is appropriately added.

In the structure shown in FIG. 3A, since the light receiving device 6 is installed in the light collecting device, the procedure for installing the light receiving device 16 in the light collecting device when actually manufacturing the light receiving device 6 is described. It can be complicated. This can be avoided, for example, by using a structure in which the light receiving device is installed on the surface of the light collecting device as shown in FIG. In this case, a second regular reflection mirror 35 for guiding light to the surface of the light receiving device 6 is required. In addition, it is desirable to place a first specular reflection surface on the end surface where the light receiving device is not installed. Further, by using a diffractive surface instead of the regular reflection surface, the incident angles of the light incident on the light receiving device can be made uniform, so that the light capturing rate of the light receiving device further increases.

The wavelength of light incident on the light condensing device as described above may be single or narrow, for example,
In the case of laser light or light from a light emitting diode,
The light collected by the light collecting device using the diffractive surface of the present invention is close to a parallel light beam. Therefore, as shown in FIGS. 19A and 19B, an exit surface 37 is provided on the end face of the light condensing device, and the light 36 emitted from the end surface is condensed by a lens, or the shape of the exit surface is changed to a lens shape. By condensing the light, the light condensing magnification can be further increased.

Embodiment 1 FIG. 20 is a view showing a schematic configuration of a light collecting device and a light collecting module according to a first embodiment of the present invention. As shown in FIG. 20, the light collecting device of the first embodiment is designed to collect sunlight in a cylindrical light receiving device and heat water flowing through the device.

First, the structure shown in FIG. 20A was used as the light collecting device. As the light receiving device 6, a cylindrical heat collecting device was used, and water flowing inside the cylinder was heated by the energy of the collected light.

As described above, since the heat collecting device is used as the light receiving device 6, in order to prevent the heated heat from escaping to the outside, the cover glass 11 on the surface and the heat insulating layer 1 using the air layer are used.
0, and a heat insulating layer 23 made of urethane foam was provided on the back surface. The diffractive surface 7 is formed by bonding a sheet having a structure in which an aluminum reflector 17 as shown in FIG. As the medium 5, a plastic having a low thermal conductivity was used.

Since the refractive index of the plastic is about 1.5, the incident angle when the incident light is reflected on the diffraction surface and reenters the light receiving surface is arcsin (1 / 1.5) = 41.8 degrees or less. Need to be For this purpose, it is desirable that the blaze angle of the diffractive surface is larger than this. Therefore, in the first embodiment, the blaze angle is set to 45 degrees.

Sunlight has a wide wavelength range from ultraviolet light having a wavelength of about 300 nm to far infrared light having a wavelength of several μm. In order to effectively condense this light by diffraction, it is necessary to design such that a sufficient diffraction angle can be obtained for short wavelength light for which it is difficult to increase the diffraction angle. The refractive index of the medium 5 is about 1.5
Therefore, the wavelength of light in the medium is 1.5 times the wavelength in air.
It's a fraction.

Since the shortest wavelength of the sunlight is about 400 nm, the second-order diffracted light is used for the shortest wavelength, and the repetition pitch of the microscopic unevenness on the diffraction surface 7 is set to the wavelength of 400 nm / 1.5 in plastic. It was 533 nm, which is twice as large.

An aluminum frame 21 was formed around a light-collecting device in which a plurality of such light receiving devices were connected, and a plastic support 12 was disposed on the back surface. With this structure, a light-collecting module having a simple structure and high light-collecting efficiency can be formed as compared with a conventional light-collecting device using a slope having a large step.

(Embodiment 2) FIG. 21 is a view showing a schematic configuration of a light collecting device and a light collecting module according to Embodiment 2 of the present invention. The condensing device according to the second embodiment has a wavelength of 106
The laser light of 4 nm was collected in a light receiving device 6 having a plate-like photoelectric conversion function, and designed to extract electric power.

First, the structure shown in FIG. 21A was used as the light collecting device. A photoelectric conversion device using a plate-shaped semiconductor was used as the light receiving device 6, the energy of the collected light was converted into electric power, and the electric power was extracted to the outside from the electrode provided in the portion 31 continuous with the light receiving device 6. . Glass was used for the medium 5. Since the refractive index of the medium 5 is about 1.5, the repetition pitch of the microscopic unevenness on the diffraction surface 7 was set to the wavelength of incident light in the glass of 1064 nm / 1.5 = 709 nm.

A plurality of such light receiving devices 6 were arranged continuously as shown in FIG. 21B, an aluminum frame 21 was formed around the light receiving device 6, and a front cover glass 22 was further placed. The power generated by the light receiving device 6 is applied to the first electrode 2 provided on the portion 31 that is located outside the diffraction surface and is continuous with the light receiving device 6.
4 and the second wiring 25, the structure can be taken out from the first wiring 26 and the second wiring 27. Further, on the back surface, a support 12 made of plastic and also protecting the back surface and a protective material 28 for the electrode portion were provided.

With this structure, a light-collecting module having a simple macroscopic structure and high light-collecting efficiency could be formed. Examples of the photoelectric conversion device include a device using a semiconductor device and a device using a photochemical reaction, but it goes without saying that the effect of the present invention does not depend on the type of the photoelectric conversion device.

(Embodiment 3) FIG. 22 is a view showing a schematic configuration of a light collecting device and a light collecting module according to Embodiment 3 of the present invention. The light collecting device of the third embodiment has a wavelength of 900 to 1000 n.
The light from the light emitting diode which generates m light is collected by the light receiving device 6 having a plate-like photoelectric conversion function and designed to extract an electric signal.

As the light receiving device (photodetector: photosensor) 6 of the third embodiment, Si, GaAs, GaAsP, G
e, a photodiode using a semiconductor such as InGaAs, a pin photodiode, an avalanche photodiode, a phototransistor, or CdS, PbS, PbSe.
There is a photoconductive element using such a method.

First, the structure shown in FIG. 22A was used as the light collecting device. A photoelectric conversion device using a plate-shaped semiconductor is used as the light receiving device 6, and the collected light is converted into an electric signal.
An electric signal was taken out from an electrode provided on the back surface of the light receiving device 6. Glass was used for the medium 5. The refractive index of the medium 5 is about 1.5. Up to the third-order diffracted light is used, and the repetition pitch of the microscopic unevenness on the diffractive surface 7 is set to a short wavelength 900 nm / 1.5 × 3 = 1800 of incident light in glass.
nm.

A plurality of such light receiving devices 6 were arranged continuously as shown in FIG. 22B, and an aluminum frame 21 was formed around the light receiving devices. The electric signal generated by the light receiving device 6 is divided into a first electrode 24 and a second electrode 2 provided on the back surface of the light receiving device.
5, the structure can be taken out from the first wiring 26 and the second wiring 27. Further, a protective material 28 made of plastic was provided on the back surface. In this module, the first reflection surface 34 and the second reflection surface 35 were formed by one reflection plate using a double-sided reflection plate.

With this structure, a light-collecting module having a simple macroscopic structure and high light-collecting efficiency could be formed. Examples of the photoelectric conversion device include a device using a semiconductor device and a device using a photochemical reaction. However, it goes without saying that the effect of the present invention does not depend on the type of the photoelectric conversion device.

The microscopic structure of the diffractive surface described so far does not need to completely match the illustrated shape, and may have irregularities that do not affect the diffraction. In addition, when actually manufacturing these surfaces, the shape may be deformed due to the limitation of the working accuracy, but if the collapse does not hinder the diffraction of light, the effect of the present invention is not obtained. Needless to say. Further, these diffraction surfaces can be easily formed by, for example, forming replicas by an embossing method.

As described above, the present invention has been specifically described based on the embodiments (examples). However, the present invention is not limited to the above-described embodiments (examples), and various modifications may be made without departing from the scope of the invention. It goes without saying that it can be done.

[0056]

The effects obtained by typical ones of the inventions disclosed in the present application are as follows.

(1) The macroscopic structure can be simplified.

(2) The light collection magnification can be increased while keeping the light use efficiency high.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a light collecting device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a shape of a surface of a diffraction surface of the light condensing device of the present embodiment viewed microscopically.

FIG. 3 is a diagram illustrating a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a heat collecting apparatus according to an embodiment of the present invention.

FIG. 5 is a diagram showing a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 6 is a diagram illustrating a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 7 is a diagram illustrating a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 8 is a diagram illustrating a schematic configuration of a light collecting device according to another embodiment of the present invention.

FIG. 9 is a diagram illustrating a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 10 is a diagram showing a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 11 is a diagram illustrating a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 12 is a diagram illustrating a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 13 is a diagram illustrating a schematic configuration of a light-collecting device according to another embodiment of the present invention.

FIG. 14 is a diagram illustrating a schematic configuration when the diffraction surface of the light collecting device according to the embodiment of the present invention is viewed from above.

FIG. 15 is a diagram showing a schematic configuration when the diffraction surface of the light-collecting module according to the embodiment of the present invention is viewed from above.

FIG. 16 is a diagram showing a schematic configuration when a diffraction surface of a light collecting apparatus according to another embodiment of the present invention is viewed from above.

FIG. 17 is a diagram illustrating a cross-sectional structure of a diffraction surface of the light-collecting device according to the embodiment of the present invention.

FIG. 18 is a diagram illustrating a cross-sectional structure of a diffraction surface of a light-collecting device according to another embodiment of the present invention.

FIG. 19 is a diagram illustrating a cross-sectional structure of a diffraction surface of a light-collecting device according to another embodiment of the present invention.

FIG. 20 is a diagram illustrating a schematic configuration of a heat collecting apparatus and a light collecting module according to the first embodiment of the present invention.

FIG. 21 is a diagram illustrating a schematic configuration of a photodetector and a light collecting module according to a second embodiment of the present invention.

FIG. 22 is a diagram illustrating a schematic configuration of a photoelectric conversion device using artificial light and a light collecting module according to a third embodiment of the present invention.

FIG. 23 is a diagram showing a schematic configuration of a conventional light collecting device.

[Explanation of symbols]

1: incident light, 2: light incident on the light condensing device, 3: reflected light,
4 light receiving surface, 5 medium, 6 light receiving device, 7 diffraction surface, 8
... Diffraction surface surface viewed microscopically, 9 ... Ditch groove pitch, 10 ...
Heat insulating layer, 11: cover, 12: support, 13: reflection curved surface, 14: diffraction groove direction, 15: right side, 16: left side, 17
... reflective material layer, 18 ... backside protective layer, 19 ... surface layer, 20
... adhesive layer, 21 ... frame, 22 ... cover glass, 23
... heat insulating plate, 24 ... first electrode, 25 ... second electrode, 26
... first wiring, 27 ... second wiring, 28 ... protective material, 29
... Rotation direction, 30 ... Rotation axis, 31 ... Continuous part of light receiving device located outside diffraction surface, 32 ... Specular reflection surface, 33 ... Incident angle, 34 ... First reflection surface, 35 ... Second reflection surface , 36
.. Light exiting from the exit surface, 37 ... exit surface.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshiaki Yazawa 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. Inside the Central Research Laboratory of the Works (72) Inventor Ken Tsutsui 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory of Hitachi, Ltd. (72) Inventor Junko Minemura 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd.

Claims (4)

[Claims] 1. A medium, comprising: a light receiving surface; a diffraction surface; a medium filling a space between the light receiving surface and the diffraction surface; and a light receiving device having at least a part of the surface in contact with the medium. Wherein the refractive index is larger than the refractive index outside the light receiving surface. 2. A heat collecting device, wherein a light receiving surface, a diffractive surface, a medium filling a space sandwiched between the light receiving surface and the diffractive surface, and at least a part of the surface contacting the medium, A heat collector, wherein a refractive index of a medium is larger than a refractive index outside the light receiving surface. 3. A light-receiving surface, a diffraction surface, a medium filling a space interposed between the light-receiving surface and the diffraction surface, and a photodetector at least a part of which is in contact with the medium, A photodetector, wherein a refractive index of a medium is larger than a refractive index outside the light receiving surface. 4. A photoelectric conversion device for artificial light, wherein a light-receiving surface, a diffraction surface, a medium filling a space between the light-receiving surface and the diffraction surface, and at least a part of the surface is in contact with the medium. An artificial light photoelectric conversion device, wherein a refractive index of the medium is larger than a refractive index outside the light receiving surface.