JPWO2012067082A1 - Condensing device, photovoltaic power generation device, and photothermal conversion device - Google Patents

Abstract

The condensing device includes a first condensing lens, a second condensing lens, a first condensing optical element that guides incident light condensed and incident by the first condensing lens, and a second condensing lens. And a second condensing optical element that guides incident light incident thereon. The condensing optical element includes an upper surface that transmits incident light, a lower surface that extends opposite to the upper surface, a reflective surface that is provided between the upper surface and the lower surface so as to intersect the optical axis of the incident light, and an opposite side of the reflective surface And an exit surface provided on the surface. The first condensing optical element and the second condensing optical element are arranged so that the reflecting surfaces of the first condensing optical element and the second condensing optical element do not overlap vertically, and the exit surfaces of the first condensing optical element and the second condensing optical element are aligned vertically. The condensing optical element and the second condensing optical element are arranged one above the other so that the light condensed by the first condensing lens and the second condensing lens and reflected by the reflecting surface is emitted. Configured to be guided to the surface.

Description

  The present invention relates to an apparatus that condenses light, and more particularly, to a condensing apparatus that condenses light incident in a thickness direction in a side surface direction, and a photovoltaic device and a photothermal conversion apparatus using the condensing apparatus.

In recent years, reduction of CO ₂ emissions has been demanded worldwide and the use of natural energy has been promoted. Regarding the use of solar energy, solar thermal energy has been used in solar water heaters and the like from the past. In addition, solar power generation systems that convert the light energy of sunlight into electrical energy have been introduced into ordinary households, and large-scale solar power plants are entering the practical stage in various countries.

  Solar cells that convert light energy into electrical energy are classified into silicon-based, compound-based, organic-based, dye-sensitized systems, and the like in terms of photoelectric conversion material classification. A cell of a general solar battery composed of such a material has a conversion efficiency from light energy to electric power of about 10 to 20%. On the other hand, the solar radiation spectrum range is divided into multiple wavelength bands, and multiple semiconductor layers with optimal band gaps for photoelectric conversion of light in each wavelength band are stacked to convert light energy to power Multi-junction type (also referred to as tandem type, stacked type, etc.) solar cells with improved efficiency up to about 40% have been developed.

  However, the high-efficiency solar cells as described above are extremely expensive and difficult to use except for special applications such as aerospace. In view of this, a concentrating solar cell module has been devised that condenses and enters sunlight into a small cell to reduce costs and to perform solar power generation with high efficiency. As a condensing type, a lens condensing type that condenses sunlight by a Fresnel lens or a reflecting mirror and directly enters the solar cell (see Patent Document 1 and Patent Document 2), a fluorescent plate in which fluorescent particles are dispersed Fluorescent plate condensing type (refer to Patent Document 3), in which sunlight is incident on the plate, and the fluorescence generated in the plate is taken out and collected to the side of the plate, and sunlight is applied to the plate between which the hologram film and the solar battery cell are sandwiched. A spectral condensing type (see Patent Document 4) that guides light diffracted by a hologram film to a solar battery cell has been proposed.

Japanese National Table 2005-142373 Japanese Unexamined Patent Publication No. 2005-217224 US Patent Application Publication No. 2006/0107993 US Pat. No. 6,274,860

  However, each condensing method has advantages, but has the following problems. For example, in the conventional lens condensing type in which sunlight is condensed by a Fresnel lens or a reflecting mirror and the convergent light is directly incident on the solar cell, the solar cell corresponding to a relatively large lens and each lens. Is provided. For this reason, there exists a subject that an apparatus enlarges according to the focal distances, such as a lens. In addition, there is a problem that the apparatus becomes complicated because a large number of solar cells are dispersedly arranged at focal positions such as lenses. The fluorescent plate condensing type and the spectral condensing type can reduce (thin) the dimension (thickness) of the module in the optical axis direction, but there is room for improvement in terms of wavelength dependency and conversion efficiency.

  This invention is made | formed in view of the above situations, and provides the new condensing apparatus which can utilize light energy, such as sunlight, efficiently with a simple apparatus.

  The 1st mode which illustrates the present invention is a condensing device. This condensing device includes a first condensing optical element that is formed of a first condensing lens and a transparent material, and that guides incident light that is condensed by the first condensing lens and incident, and a second condensing lens. , And a second condensing optical element that guides incident light that is condensed by the second condensing lens and is incident by the second condensing lens. Each of the first condensing optical element and the second condensing optical element intersects the optical axis of the incident light between the upper surface transmitting the incident light, the lower surface extending opposite to the upper surface, and the upper surface and the lower surface. And reflecting surfaces that reflect incident light (for example, the condensing reflecting surfaces 25 and 35 in the embodiment) and an exit surface provided on the opposite side of the reflecting surface, The reflection surface and the reflection surface of the second condensing optical element do not overlap vertically, and the first condensing optical element emission surface and the second condensing optical element emission surface are aligned vertically. The condensing optical element and the second condensing optical element are arranged one above the other so that the light condensed by the first condensing lens and the second condensing lens and reflected by the reflecting surface is reflected. The first condensing optical element and the second condensing optical element are configured to be guided to the emission surfaces. For convenience, the surface through which incident light is transmitted is referred to as the “upper surface”, and the surface opposite to the upper surface is referred to as the “lower surface”. It is optional and does not define the position or orientation.

  In this case, the reflecting surface is set so that the minimum incident angle of light incident on the reflecting surface at a predetermined focusing angle or diverging angle by the condenser lens is equal to or greater than the total reflection angle at the interface between the reflecting surface and air. It is preferable. The reflecting surface is preferably formed in a curved surface shape that suppresses the spread angle after reflection of incident light incident at a predetermined focusing angle or divergence angle by the condenser lens. Further, the reflecting surface is preferably set so that the minimum incident angle of the light beam reflected by the reflecting surface and incident on the lower surface and / or the upper surface is equal to or greater than the total reflection angle at the interface between these surfaces and air. .

  The first condensing optical element and the second condensing optical element have a first side surface and a second side surface that connect the upper surface and the lower surface and face each other across the emission surface, and are incident and reflected from the upper surface. It is preferable that the light reflected by the surface is totally reflected by the upper surface, the lower surface, the first side surface and the second side surface and guided to the output surface.

  In the above aspect of the present invention, the first condensing optical element and the second condensing optical element that are arranged one above the other are arranged in close contact with each other, and the upper and lower surfaces that are in close contact are matched by matching. It is preferable to be configured to be integrally coupled.

  The first condenser lens and the second condenser lens are each composed of a plurality of unit condenser lenses for condensing light, and the first condenser optical element and the second condenser optical element are respectively It is preferable that a plurality of reflecting surfaces provided corresponding to each incident light that is collected by the unit condenser lens and incident thereon are formed integrally.

  Further, it is preferable that a plurality of first side surfaces are provided corresponding to the respective reflecting surfaces, and a second side surface is provided integrally with the plurality of reflecting surfaces. In this case, the first condensing optical element and the second condensing optical element are symmetrical with respect to an axis (for example, the x axis in the embodiment) in which the first side surface and the second side surface extend in the emission direction. It is preferable to form it as follows.

  Further, each of the first condenser lens and the second condenser lens has a plurality of unit condenser lenses arranged in a matrix to form a lens array, and the first condenser optical element and the second condenser lens are formed. The optical optical element is preferably configured such that a plurality of element units each having a reflecting surface, a first side surface, and a second side surface are provided corresponding to the unit condenser lens in each row and are integrally formed. Further, it is preferable that the plate is formed in a plate shape or a sheet shape in which the size in the direction connecting the reflection surface and the output surface is sufficiently larger than the size in the thickness direction connecting the upper surface and the lower surface.

  A second aspect illustrating the present invention is a photovoltaic device. The photovoltaic device according to this aspect includes the light collecting device according to the first aspect and a photoelectric conversion element that photoelectrically converts light guided to the emission surface by the light collecting device.

  A third aspect illustrating the present invention is a photothermal conversion device. The photothermal conversion device according to this aspect includes the light condensing device according to the first aspect and a photothermal conversion element that photothermally converts the light guided to the emission surface by the light condensing device.

  The condensing device according to the first aspect of the present invention provides the first condensing device such that the reflecting surfaces of the first condensing optical element and the second condensing optical element do not overlap vertically and the exit surfaces are aligned vertically. The optical element and the second condensing optical element are arranged one above the other so that the light condensed by the first condensing lens and the second condensing lens and reflected by the reflecting surfaces is lined up and down. It is comprised so that it may be guide | induced to the output surface. Therefore, according to the condensing device of the first aspect of the present invention, it is possible to provide a new condensing device that can improve the condensing efficiency and efficiently use light energy such as sunlight.

  The photovoltaic device according to the second aspect of the present invention includes the above-described condensing device and a photoelectric conversion element that photoelectrically converts light collected by the condensing device. For this reason, the photovoltaic device which can utilize light energy, such as sunlight efficiently, with a thin and simple structure can be provided.

  A photothermal conversion device according to a third aspect of the present invention includes the above-described condensing device and a photothermal conversion element that photothermally converts the light collected by the condensing device. For this reason, the photothermal conversion apparatus which can utilize light energy, such as sunlight efficiently, with a thin and simple structure can be provided.

FIG. 1 is an external perspective view of a photovoltaic power generator PVS illustrating an embodiment of the present invention. FIG. 2 is a conceptual diagram for explaining the basic configuration of the condensing device 1 of the first configuration form in the photovoltaic power generation device PVS. FIG. 3 is a conceptual diagram of a side view illustrating a simulation result of ray tracing of the propagation state of light condensed and incident on the condensing optical element by the condensing lens in the condensing device 1. FIG. 4 is an enlarged image of the vicinity of the condensing reflection surface in FIG. FIG. 5 is a perspective view of the light collecting device 1a of the first configuration example in the light collecting device 1. FIG. FIG. 6 is a side view of the light collecting device 1a. FIG. 7 is a plan view and a side view of the condensing optical element 20I (20A, 20B, 20C) constituting the condensing device 1a. FIG. 8 is a plan view and a side view of the condensing optical elements 20A and 20B in the condensing optical element 20I. FIG. 9 is a plan view and a side view of the condensing optical element 20C (condenser 20s) in the condensing optical element 20I. FIG. 10 is a perspective view of the element unit of the condensing optical element 20I as viewed obliquely from above. FIG. 11 is a perspective view of the light collecting device 1b of the second configuration example in the light collecting device 1. FIG. FIG. 12 is a side view of the light collecting device 1b. FIG. 13 is a plan view of the condensing optical elements 20A, 20B, and 20C constituting the condensing device 1c of the third configuration example in the condensing device 1. FIG. FIG. 14 is a side view of the light collecting device 1c. FIG. 15 is a schematic diagram for explaining the basic configuration of the condensing optical element 20II in the condensing device 2 of the second configuration form. FIG. 16 is an explanatory diagram for explaining the relationship between incident light collected by the condenser lens and incident thereon and the condensing reflection surface in the condensing optical element 20II. FIG. 17 is a perspective view of the condensing optical element 20C (condenser 20s) of the condensing optical element 20II as viewed obliquely from above. 18A is an enlarged perspective view of the optical structure of the condensing optical element 20II, and FIG. 18B is a diagram of the condensing optical element 20C (the condensing unit 20s ₁ ) of the first configuration example in the condensing device 2. FIG. 18C is a conceptual diagram illustrating the orientation configuration of the reflected light, and FIG. 18C is a conceptual diagram illustrating the orientation configuration of the reflected light of the condensing optical element 20C (the condensing unit 20 ₂ ) of the second configuration example in the condensing device 2. is there. FIG. 19 is a conceptual diagram of the light concentrating device of the third configuration example in the light concentrating device 2. FIG. 20 is a table showing the relationship between the wavelength and the refractive index in PMMA. FIG. 21 is a graph showing the radiation spectrum distribution of sunlight. FIG. 22 is a side view conceptual diagram illustrating a simulation result when sunlight is incident on the light concentrating device 1 of the first configuration form. FIG. 23 is a conceptual diagram illustrating a simulation result when sunlight is incident on the concentrating device 1 of the first configuration form, as viewed from obliquely above. FIG. 24A is an enlarged view of a simulation result when sunlight is incident on the light collecting device 1a, and FIG. 24B is a simulation when sunlight is incident on the light collecting device 1a. It is the enlarged view which looked at the result from condensing optical element 20A, 20B, 20C from the upper part. 25 (a), (b), and (c) are partially enlarged views of the simulation results of the condensing device 1a when viewed from the side of the condensing optical elements 20A, 20B, and 20C, respectively. . FIG. 26 is an explanatory diagram showing the illuminance distribution of the light emitted from the output unit of the light collecting device 1a. FIG. 27A is an enlarged view of a simulation result when sunlight is incident on the light collecting apparatus 1a to which the light collecting optical elements 20A, 20B, and 20C are bonded, and FIG. It is the enlarged view which looked at condensing optical element 20A, 20B, 20C from the upper direction, and the simulation result when sunlight injects into the condensing apparatus 1a which adhere | attached optical optical element 20A, 20B, 20C. 28 (a), (b), and (c) are partially enlarged views of the simulation results of the condensing device 1a when viewed from the side of the condensing optical elements 20A, 20B, and 20C, respectively. . FIG. 29 is an explanatory diagram showing the illuminance distribution of the light emitted from the output unit of the light collecting device 1a. FIG. 30A is an enlarged view of a simulation result when sunlight is incident on the light collecting device 1c, and FIG. 30B is a simulation when sunlight is incident on the light collecting device 1c. It is the enlarged view which looked at the result from upper direction of condensing optical element 20A, 20B, 20C. 31 (a), (b), and (c) are partially enlarged views of the simulation results of the light collecting device 1c when viewed from the side of the light collecting optical elements 20A, 20B, and 20C, respectively. . FIG. 32 is an explanatory diagram showing the illuminance distribution of the light emitted from the output unit of the light collecting device 1c. FIG. 33 is a conceptual diagram illustrating a method for extracting light energy from the condensing optical element. FIG. 34A is a perspective view of the condensing device 1d, and FIG. 34B is a plan view of the condensing optical element 20I (20A, 20B, 20C) constituting the condensing device 1d.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows an external perspective view of a photovoltaic power generator PVS illustrating an embodiment of the present invention. Moreover, the conceptual diagram for demonstrating the principle of the condensing apparatus 1 of the 1st structure form in the photovoltaic device PVS is shown in FIG. In order to clarify the explanation, a coordinate system composed of an x-axis, a y-axis and a z-axis orthogonal to each other is defined, and this is shown in FIG. The z-axis is an axis extending in the thickness direction of the light collecting device 1 in the photovoltaic device PVS, the x-axis is an axis extending in the extraction direction of light collected and extracted by the light collecting device 1, and the y-axis is these two axes. It is an axis extending in an orthogonal direction. For convenience of explanation, the orientation shown in FIG. 2 may be referred to as up, down, left, and right, but the orientation of the photovoltaic device PVS is arbitrary depending on the incident direction of light, and does not define the position or orientation.

[Outline of photovoltaic device and condensing device]
In order to grasp the outline of the entire apparatus, first, the overall configuration of the photovoltaic power generation apparatus PVS will be described. The photovoltaic device PVS includes condensing devices 1 and 2 that collect incident light, and a photoelectric conversion element 5 that photoelectrically converts the light collected by the condensing devices 1 and 2 and guided to the end. Configured. 1 and 2 are formed of a first condensing lens 10A and a second condensing lens 10B that condense light (for example, sunlight) incident from above and a transparent material. The first condensing optical element 20A and the second condensing optical element 20B that guide incident light that is condensed by the first condensing lens and the second condensing lens are configured.

  The first condenser lens 10A, the second condenser lens 10B, the first condenser optical element 20A, and the second condenser optical element 20B are each basically a plurality of condenser lenses or condenser optics having the same structure. It is configured by combining elements. The condensing lens 10 (10A, 10B) and the condensing optical element 20 (20A, 20B) are manufactured using, for example, an inorganic material such as optical glass or a resin material such as PMMA. FIG. 1 shows an example in which two sets of condensing structures including a condensing lens and a condensing optical element are provided, but the number of condensing lenses and condensing optical elements may be three or more.

  The condensing lens 10 (10A, 10B) shown in FIG. 1 includes a plurality of unit condensing lenses indicated by subscripts in a plurality of rows × a plurality of columns (m rows × n columns, in the x-axis direction and the y-axis direction, An example in which m and n are natural numbers) is configured by a lens array arranged in a matrix. The lens array may be configured by integrally molding a plurality of unit condenser lenses in a matrix shape, or may be configured by arranging and fixing individually formed unit condenser lenses in a matrix form on a frame or the like. Also good.

The condensing optical element 20 (20A, 20B) has a condensing reflection surface that reflects incident light that is collected and incident by a unit condensing lens that is each condensing lens. It is configured to guide in the x-axis direction. The condensing optical element 20 shown in FIG. 1 has a plurality (m rows × n) corresponding to each incident light that is condensed and incident by a plurality of unit condensing lenses 10 ₁₁ , 10 ₁₂ ,... 10 _{m 1} , 10 _{m 2 ,.} This is an example of a configuration in which the light collecting and reflecting surfaces are arranged in a single plate. As the photoelectric conversion element 5, various known elements can be used, and for example, the photoelectric conversion element 5 can be configured using the solar cells of various forms described above.

  Here, the condensing optical element 20 differs in the condensing device 1 of the 1st structure form and the condensing apparatus 2 of the 2nd structure form mentioned later. Therefore, when distinguishing between them, the condensing optical element 20 of the first configuration form is referred to as a condensing optical element 20I, and the condensing optical element 20 of the second configuration form is referred to as a condensing optical element 20II.

[Condenser of First Configuration]
FIG. 2 is a schematic diagram for explaining the basic configuration of the condensing optical element 20I in the condensing device 1 of the first configuration form, and the light collected by the condensing lens 10 and incident on the condensing optical element 20I. FIG. 6 is a diagram schematically illustrating a state in which the light is reflected by the condensing reflection surface 25 and propagates in the element.

  The condensing optical element 20I includes an upper surface 22 that transmits incident light that is collected by the condensing lens 10 and is incident on the base material 21, a lower surface 23 that extends in parallel to face the upper surface, and an upper surface 22 and a lower surface 23. It has a condensing reflection surface 25 provided to intersect the optical axis LA of incident light and reflecting incident light, and an exit surface 26 provided on the opposite side of the condensing reflection surface 25. The form to show shows the structure which used the condensing reflective surface 25 as the inclined plane which connects an upper surface and a lower surface.

  3 and 4, a ray-trace simulation of how the light collected by the condenser lens 10 and incident on the condenser optical element 20I propagates inside the condenser optical element 20. Results are shown. 4 is a simulation result in which the vicinity of the condensing reflection surface 25 in FIG. 3 is enlarged, and FIG. 4A is a view of the vicinity of the condensing reflection surface 25 in the y-axis direction, and FIG. These are the figures which looked at the vicinity of the condensing reflective surface 25 from diagonally downward.

  As shown in FIG. 4B, the condensing optical element 20I connects the condensing reflection surface 25 and the exit surface 26 between the upper surface 22 and the lower surface 23, and extends in parallel so as to face each other. It has 24a and 2nd side surface 24b, and is formed so that a yz cross section may become a square.

  The light that is incident on the upper surface 22 while being condensed by the condenser lens 10 and is reflected by the condenser reflection surface 25 spreads in a conical shape or a pyramid shape according to the shape of the condenser lens 10, and enters the condensing optical element 20. To propagate. In the condensing optical element 20, light incident from the upper surface 22 is totally reflected on the condensing reflection surface 25, the upper surface 22, the lower surface 23, the first side surface 24 a, and the second side surface 24 b, and the x-axis direction (rightward in FIG. 2). ) And is extracted to the exit surface 26.

With respect to the light collected by the condenser lens 10 and incident on the condenser reflection surface 25, the optical axis passes through the center of the condenser lens 10 as shown in the partially enlarged view in the vicinity of the condenser reflection surface in FIG. The angle of incidence of light incident on the condensing reflection surface 25 along LA (for convenience, the “optical axis incident angle”) θ1 _LA and the optical axis LA through the outer periphery of the position condensing lens 10 are Therefore, the incident angle of the light ray incident on the condensing reflection surface 25 is different. As is clear from this partial enlarged view, the incident angle of the light beam that enters the condensing reflection surface 25 through the lens outer peripheral portion on the reflection direction side by the condensing reflection surface 25 is the minimum incident angle θ1 _min .

In the condensing optical element 20, the minimum incident angle θ < _b > 1 _min of the light beam that is collected and incident on the condensing reflection surface 25 is set to be equal to or greater than the total reflection angle on the condensing reflection surface 25. Specifically, the refractive index n of the base material 21 of the condensing optical element and the numerical aperture NA of the condensing lens 10 (NA = n sin θ _NA : θ _NA is the maximum angle with respect to the optical axis LA of the light beam emitted from the condensing lens). The inclination angle θ ₂₅ of the condensing / reflecting surface 25 can be set so that the minimum incident angle θ 1 _min is equal to or greater than the total reflection angle at the condensing / reflecting surface 25.

The refractive index n of the base 21 of the condensing optical element and the inclination angle θ ₂₅ of the converging / reflecting surface ₂₅ are set to predetermined values, and the light is collected so that the minimum incident angle θ 1 _min is equal to or greater than the total reflection angle on the condensing / reflecting surface 25. The numerical aperture NA of the optical lens 10 (generally, the focal length f of the condenser lens 10) may be set. Alternatively, the condensing optics so that the numerical aperture NA of the condensing lens 10 and the inclination angle θ ₂₅ of the condensing reflection surface 25 are set to predetermined values, and the minimum incident angle θ 1 _min is equal to or greater than the total reflection angle on the condensing reflection surface 25. It is also possible to set the refractive index n of the base material 21 of the element, specifically by selecting the material of the base material 21 and the additive to be doped.

When the entire light totally reflected by the condensing / reflecting surface 25 is incident on the lower surface 23, the light beam incident and reflected by the condensing / reflecting surface 25 at the minimum incident angle θ 1 _min is maximally incident on the lower surface 23 (and the upper surface 22). Enter at the corner. On the other hand, a light beam incident and reflected on the condensing reflection surface 25 at the maximum incident angle enters the lower surface 23 (and the upper surface 22) at the minimum incident angle θ2 _min . Accordingly, the inclination angle θ of the condensing / reflecting surface 25 is set so that each of the condensing / reflecting surface 25, the upper surface 22, the lower surface 23, the first side surface 24a, and the second side surface 24b satisfies the condition of total reflection at the interface with air. ₂₅ , the numerical aperture NA of the condenser lens 10 and the refractive index n of the condenser optical element 20 are set.

  According to such a configuration, the incident light that is condensed by the condenser lens 10 and incident from the upper surface 22 of the condenser optical element 20 enters the condenser optical element 20, and then all the interfaces with air. The light is totally reflected by the condensing reflection surface 25, the upper surface 22, the lower surface 23, the first side surface 24 a, and the second side surface 24 b, and is guided to the emission surface 26. Therefore, the wavelength dependency of the light incident on the condensing optical element 20 is low and the confinement efficiency can be increased, so that the condensed light can be guided to the emission surface 26 with high efficiency.

  When a film such as a protective film having a refractive index different from that of the base material 21 is formed on any of the above surfaces, for example, the lower surface 23, light corresponding to the refractive index of the film at the interface between the base material 21 and the film. Refraction occurs. However, Snell's law is established at the interface between the base material 21 and the film and between the film and air, and the inclination angle of the light incident on the lower surface 23 is greater than the total reflection angle at the interface between the base material 21 and the air. If so, the total reflection condition is satisfied at least at the interface between the film and air, and the incident light is confined in the condensing optical element 20.

  Further, in the configuration having the above protective film or the like, when the inclination angle of the light incident on the lower surface is equal to or greater than the total reflection angle at the interface between the base material 21 and the film, at the interface between the base material 21 and the film The total reflection condition is satisfied, and the light incident on the lower surface is totally reflected into the substrate without entering the film. Therefore, even when the total reflection condition cannot be maintained at the interface between the film and air because the outer surface of the film is not smooth, the light incident on the condensing optical element 20 is confined in the condensing optical element 20, and the exit surface 26 is taken out.

  In the condensing device 1, the condensing lens 10 and the condensing optical element 20 </ b> I focus incident light that is condensed by the condensing lens 10 and enters the element on or near the condensing reflection surface 25. Configured to tie. Note that the refractive index of the substance varies depending on the wavelength λ of the transmitted light. Therefore, when the wavelength λ of the light to be collected has a width, the focal position of the light on the short wavelength side and the focal position of the light on the long wavelength side are generally different, and the focal position is wide in the wavelength band. It has a corresponding width. In the light condensing device 1, the wavelength of incident light is set to λ = 350 to 1100 nm according to the radiation spectrum of sunlight, and a lens with little chromatic aberration is used as the condensing lens 10 and a beam spot on the condensing reflection surface 25. The diameter is set to be the minimum.

  With such a configuration, the projected area of the condensing reflection surface 25 can be minimized, and thereby the thickness of the condensing optical element 20I can be minimized. If the wavelength band of incident light is narrow or if chromatic aberration can be compensated, the focal position of incident light can be set on the condensing reflection surface 25. On the other hand, you may comprise so that it may defocus slightly according to the power density etc. of the incident light in a focus position.

  The light totally reflected by the condensing reflection surface 25 is totally reflected by each of the upper surface 22, the lower surface 23, the first side surface 24a, and the second side surface 24b, propagates in the optical element 20 in the x-axis direction, and is emitted. 26. In the configuration shown in the drawing, the exit surface 26 is formed along the yz plane and the end surface is polished and anti-reflection coating is applied, and light that propagates through the optical element 20 and enters the exit surface 26. However, the light is emitted without being reflected by the light exit surface 26 and enters the photoelectric conversion element 5.

The basic configuration (unit configuration) of the condensing optical element 20I has been described above. In the description, the condensing / reflecting surface 25 is described as having a total reflection using a difference in refractive index, but a mirror on which a metal such as Au, Ag, or Al is deposited is formed on the condensing / reflecting surface 25. Thereby, it can also be set as the structure which reflects incident light. In this case, the reflection loss in the light converging reflection surface 25 is generated, it is possible to reduce the optical axis incident angle .theta.1 _LA (small inclination angle theta ₂₅ of condensing and reflecting surface 25). For example, if the optical axis incident angle θ _{25 is set} to 45 degrees, the minimum incident angle of the light reflected by the condensing reflection surface 25 to the upper surface 22, the lower surface 23, the first side surface 24a, and the second side surface 24b increases. Therefore, a short-focus condenser lens having a larger numerical aperture can be used, whereby the thickness of the condenser 1 can be reduced. For the sake of simplicity of explanation, the case where the condensing reflection surface 25 is a flat surface is illustrated, but a convex or concave surface having a predetermined shape such as a condensing reflection surface 35 of the condensing optical element 20II of the second configuration form to be described later. And so on.

  Next, a specific configuration example of the condensing device 1 of the first configuration form will be described in the case where the condensing device is configured by three sets of the condensing lens 10 and the condensing optical element 20. First, the condensing apparatus 1a of the 1st structural example in this structure form is demonstrated with reference to FIGS. 5 is a perspective view of the condensing device 1a, FIG. 6 is a side view of the condensing device 1a, FIG. 7 is a plan view and a side view of the condensing optical elements 20A, 20B, and 20C constituting the condensing device 1a. 9 is a plan view and a side view of the condensing optical elements 20A and 20B, FIG. 9 is a plan view and a side view of the condensing optical element 20C, and FIG. 10 is a perspective view of the element unit of the condensing optical element 20C as viewed obliquely from above. is there.

  In each figure, the condensing reflection surface 25 seen through when the condensing optical element is viewed from above is indicated by a solid line. The numerical values 1 to 30 shown in FIGS. 6 to 8 corresponding to the optical axis of the condensing lens are the number of unit condensing lenses and condensing reflection surfaces 25 in the condensing optical elements 20A, 20B, and 20C. Are the column numbers in the order from the upstream side (20A side), 1 to 10 are the condensing optical elements 20A, 11 to 20 are the condensing optical elements 20B, and 21 to 30 are the unit collections of the condensing optical elements 20C. Corresponds to optical lens or condensing reflection surface.

  The condensing device 1a includes three condensing lenses (lens arrays) 10A, 10B, and 10C and three condensing optical elements 20A, 20B, and 20C, and the condensing lenses 10A, 10B, and 10C and the condensing optical elements. Each of 20A, 20B, and 20C has a unit condenser lens of m rows × n columns and a condensing reflection surface 25 corresponding thereto.

  As shown in FIGS. 7 to 9, the condensing optical elements 20A, 20B, and 20C are mainly composed of a comb-like condensing part 20s having condensing reflection surfaces 25 of m rows × n columns. As shown in FIG. 10, the light condensing unit 20 s is composed of m element units 200 (201, 202, 203...) In which the light converging reflection surfaces 25 for 1 row × n columns are formed. Lines) Composed in parallel. Each figure illustrates a configuration form in which m = n = 10, that is, 10 rows × 10 columns.

  In each element unit 200, ten condensing / reflecting surfaces 25, 25, 25,... Are arranged at predetermined intervals along the x-axis. These light collecting / reflecting surfaces 25, 25, 25... Are arranged so that the light reflected by each light collecting / reflecting surface is not applied to other light collecting / reflecting surfaces, that is, not blocked by other light collecting / reflecting surfaces. The condensing reflection surface 25, the first side surface 24a, and the second side surface 24b are formed to be slightly inclined from the x axis (inclined in the left-right direction by several degrees in FIG. 9). The second side surface 24b is formed by one continuous plane, and the first side surface 24a is formed in a stepped shape or a saw blade shape with the condensing reflection surface 25 interposed therebetween.

  That is, in the element unit 200, 10 prismatic unit condensing elements each having an upper surface 22, a lower surface 23, a condensing reflection surface 25, a first side surface 24a, a second side surface 24b, and an exit surface 26 are bundled in parallel. The first side surface 24a and the second side surface 24b that are in contact with each other are removed to share the side surface, thereby integrating the 10 unit condensing elements integrally. The condensing part 20s of each condensing optical element 20A, 20B, 20C is formed by arranging ten element units 200 in parallel and forming an integral plate, and 100 unit condensing elements are integrated together. It corresponds to a functional element.

  In the condensing device 1, the condensing reflection surfaces 25, 25, 25... Of the condensing optical elements 20A, 20B, and 20C do not overlap vertically, and the exit surfaces 26 of the respective condensing optical elements are aligned vertically. Configured. Specifically, in the condensing optical elements 20A and 20B, as shown in FIG. 8, the base material 21 is extended in the x-axis direction to form a flat light guide 20t. The condensing optical element 20B is placed on the light guide portion 20t of the condensing optical element 20A, and the condensing optical element 20C is placed on the light guide portion 20t of the condensing optical element 20B. The emission surfaces 26, 26, 26 of the optical elements 20A, 20B, 20C are arranged side by side.

  At this time, the condensing reflection surface 25 of the condensing optical element 20A, the condensing reflection surface 25 of the condensing optical element 20B, and the condensing reflection surface 25 of the condensing optical element 20C are height positions in the z-axis direction. Are different by the thickness of the light guide 20t. On the other hand, the condensing lenses 10A, 10B, and 10C of the condensing device 1a of the first configuration example are all the same lens in which unit condensing lenses having the same focal length (for example, focal length f = 20 mm) are arranged in a matrix. An array. Therefore, in the condensing device 1a of the first configuration example, the height positions of the condensing lenses 10A, 10B, and 10C are changed in accordance with the difference in the height position of the condensing reflection surface (see FIG. 6). Incident light that enters the condensing optical elements 20A, 20B, and 20C via the optical lens is set to enter the condensing reflection surface 25 of each condensing unit 20s under the same conditions.

  As a result, the light incident on the condensing unit 20s of each condensing optical element is collected and reflected by the condensing reflection surface 25, the upper surface 22, the lower surface 23, the first side surface 24a in each element unit 200 (201 to 210) of the condensing unit. The light is totally reflected by the second side surface 24b, and the light for one row (10 places) is collected for each element unit 200, and the light condensed by each element unit is collected to be the exit surface of each condensing optical element 26. The exit surfaces 26, 26, and 26 of the condensing optical elements 20A, 20B, and 20C are arranged side by side, and the light condensed by the three condensing lenses and the condensing optical element is thus obtained. The light is emitted from the output unit 27 gathered in one place.

Now, for the condensing lenses 10A, 10B, and 10C, a 10 × 10 mm unit condensing lens is provided as a 100 × 100 mm lens array, and the exit surface 26 of each condensing optical element is 1 mm thick. If the width is 100 mm, the light incident on the 30000 mm ² condensing surface can be condensed with a condensing efficiency of 100 times and taken out from one output section 27 having a thickness of 3 mm × width of 100 mm.

  According to the condensing device 1a having such a configuration, the condensing efficiency can be increased with a simple and thin configuration with almost no loss. Further, since the light condensed by the plurality of condensing optical elements 20 can be taken out from one output unit 27, the photoelectric conversion element 5, the photothermal conversion device, and the like can be collectively arranged, and the device can be downsized. In addition, the degree of freedom in device design can be improved.

  In addition, the lens array of the condensing optical element 20 and the condensing lens 10 can be comprised, for example, by hot press molding using low-melting glass or injection molding of a resin such as PMMA, etc., with good productivity. Can be produced at a low price. The condensing optical elements 20A, 20B, and 20C can use the condensing optical element 20C in common as the condensing unit 20s, and the condensing optical elements 20A and 20B have an exit surface 26 of the condensing optical element 20C. Further, a flat light guide portion 20t having an appropriate length can be integrally coupled by bonding or the like. Alternatively, the three condensing optical elements may be integrally coupled by dropping a matching oil, an optical adhesive, or the like onto the overlapping portion of the converging optical elements 20A, 20B, and 20C that overlap in the vertical direction.

  Next, the condensing device 1b of the second configuration example in the first configuration mode will be described with reference to FIGS. 11 is a perspective view of the light collecting device 1b corresponding to FIG. 5, and FIG. 12 is a side view of the light collecting device 1b corresponding to FIG. The condensing device 1b has the same configuration as the condensing device 1a of the first configuration example described above with respect to the condensing optical element 20 (20A, 20B, 20C), while the condensing lens 10 (10A, 10B, 10C). The configuration is different.

  As described above, in the condensing device 1a, the condensing optical elements 20A, 20B, and 20C include the condensing optical element 20A so that the condensing portions 20s provided with the condensing reflection surfaces 25 do not overlap vertically. A condensing optical element 20B is disposed on the light guide 20t, and a condensing optical element 20C is disposed on the light guide 20t of the condensing optical element 20B. For this reason, the condensing reflection surface 25 of the condensing optical element 20A, the condensing reflection surface 25 of the condensing optical element 20B, and the condensing reflection surface 25 of the condensing optical element 20C are height positions in the z-axis direction. Are different by the thickness of the light guide 20t.

  On the other hand, in the condensing device 1b of the second configuration example, the focal length f of the unit condensing lens constituting each condensing lens (lens array) is collected and reflected for the condensing lenses 10A, 10B, and 10C. The height is different depending on the height position of the surface 25. For example, when the thickness of the condensing optical elements 20A and 20B is 1 mm, f = 21 mm as a unit condensing lens constituting the condensing lens 10A, and f as a unit condensing lens constituting the condensing lens 10B. = 20 mm lens, f = 19 mm lens is used as the unit condenser lens constituting the condenser lens 10C.

  For this reason, incident light that enters the condensing optical elements 20A, 20B, and 20C via the condensing lenses 10A, 10B, and 10C enters the condensing unit 20s of each condensing optical element with the same focal position relationship. Then, in the element unit 200 of the condensing unit 20s, the light that is totally reflected by the condensing reflection surface 25, the upper surface 22, the lower surface 23, the first side surface 24a, and the second side surface 24b and collected by each element unit is collected. It is taken out from the exit surface 26 of each condensing optical element. The exit surfaces 26, 26, and 26 of the condensing optical elements 20A, 20B, and 20C are arranged side by side, and the light condensed by the three condensing lenses and the condensing optical element is thus obtained. The light is emitted from the output unit 27 gathered in one place.

  Therefore, the condensing device 1b of this configuration also has a simple and thin configuration with almost no loss and high condensing efficiency. Further, since the light condensed by the plurality of condensing optical elements 20 can be taken out from one output unit 27, the photoelectric conversion element 5, the photothermal conversion device, and the like can be collectively arranged, and the device can be downsized. In addition, the degree of freedom in device design can be improved. Furthermore, since no step is generated on the upper surface of the condensing lens, it is possible to eliminate the influence of the rain caused by rainwater, dust, etc. or the shadow caused by the step. In addition, you may comprise using the condensing optical elements 20A, 20B, and 20C from which the inclination angle etc. of a condensing reflective surface differ (optimized) according to the focal distance of the condensing lenses 10A, 10B, and 10C.

  Next, the condensing apparatus 1c of the 3rd structural example in a 1st structural form is demonstrated with reference to FIG.13 and FIG.14. Here, FIG. 13 is a plan view of the condensing optical element corresponding to FIG. 7, and FIG. 14 is a side view of the condensing device 1c corresponding to FIG. The condensing device 1c has the same configuration as the condensing device 1a of the first configuration example described above with respect to the condensing lens 10 (10A, 10B, 10C), while the condensing optical element 20 (20A, 20B, 20C). The configuration is different.

  That is, in the condensing device 1a of the first configuration example, the same condensing unit is used as the condensing unit 20s of the condensing optical elements 20A, 20B, and 20C. On the other hand, in the condensing device 1c of the third configuration example, different condensing portions are used for the condensing optical elements 20A and 20C and the condensing optical element 20B, as can be seen by comparing FIG. 7 and FIG. ing.

  Specifically, the condensing portions of the condensing optical elements 20A and 20C and the condensing portion of the condensing optical element 20B are formed so as to be symmetrical in the left-right direction with respect to the x axis. As described above, the element unit 200 forming the light condensing part 20s is formed with ten condensing reflection surfaces 25, 25, 25... Arranged at predetermined intervals along the x axis. The light collecting / reflecting surfaces 25, 25, 25... Are arranged so that the light reflected by each light collecting / reflecting surface is not blocked by other light collecting / reflecting surfaces. Two side surfaces 24b are formed to be slightly inclined from the x axis (inclined in the left-right direction by several degrees with respect to the x axis).

  In the condensing device 1c, the condensing portions of the condensing optical elements 20A and 20C and the condensing portion of the condensing optical element 20B are formed so as to be inclined with respect to the x axis. 25 and the first side surface 24a and the second side surface 24b are inclined in directions opposite to the left and right in the x-axis direction, and are reflected by the condensing reflection surfaces 25, 25, 25... Of the condensing optical elements 20A, 20C. And the traveling direction of the light reflected by the condensing reflection surfaces 25, 25, 25,... Of the condensing optical element 20B are configured to be symmetrical in the x-axis direction.

  Also in the condensing device 1c having such a configuration, the condensing efficiency can be increased with a simple and thin configuration with almost no loss. Further, since the light condensed by the plurality of condensing optical elements 20 can be taken out from one output unit 27, the photoelectric conversion element 5, the photothermal conversion device, and the like can be collectively arranged, and the device can be downsized. In addition, the degree of freedom in device design can be improved. Further, in the condensing device composed of a plurality of condensing optical elements, the traveling direction of the light collected by each condensing optical element and traveling toward the exit surface 26 is symmetric in the x-axis direction. Can be made uniform in the illuminance distribution of the condensed light in the output unit 27 in which the output surfaces 26, 26,. Thereby, the conversion efficiency into electric power by the photoelectric conversion element 5 can be increased. It should be noted that the number and arrangement order of condensing optical elements having different inclination directions are arbitrary.

  Next, the condensing device 1d of the third configuration example in the first configuration mode will be described with reference to FIG. FIG. 34A is a perspective view of the condensing device 1a, and FIG. 34B is a plan view of the condensing optical elements 20A, 20B, and 20C. FIG. 34A shows that this condensing device is configured as a set of two rows of condensing lenses and one condensing optical element corresponding thereto. As shown in FIG. 34 (a), the condensing portion 20s is provided with a total of 20 condensing reflection surfaces, 10 on each side. That is, a total of 20 condensing reflection surfaces are formed on both sides of the light condensing unit 20s, 10 on each side.

  The condensing reflection surface 25 of the condensing optical element 20A, the condensing reflection surface 25 of the condensing optical element 20B, and the condensing reflection surface 25 of the condensing optical element 20C are guided in height in the z-axis direction. It differs by the thickness of the part 20t. The condensing lenses 10A, 10B, and 10C of the condensing device 1a are all the same lens array in which unit condensing lenses having the same focal length (for example, focal length f = 20 mm) are arranged in a matrix. For this reason, the height positions of the condensing lenses 10A, 10B, and 10C are made different according to the difference in the height position of the condensing and reflecting surfaces, and the condensing optical elements 20A, 20B, and 20C are arranged via the condensing lenses. Incident light is set so as to be incident on the condensing reflection surface 25 of each condensing unit 20s under the same conditions.

  The light incident on the condensing unit 20 s of the condensing optical element is totally reflected by the condensing reflection surface 25, the upper surface 22, the lower surface 23, the first side surface 24 a, and the second side surface 24 b, and is extracted from the emission surface 26. The exit surfaces 26, 26, and 26 of the condensing optical elements 20A, 20B, and 20C are arranged side by side, and the light condensed by the three condensing lenses and the condensing optical element is thus obtained. The light is emitted from the output unit 27 gathered in one place.

  As described above, in the condensing part provided with the condensing / reflecting surfaces on both sides, the tip part has a relatively large size as compared with the condensing part provided with the condensing / reflecting surface on one side. As a result, even if the size of the condensing reflection surface is as small as several millimeters, the tip of the condensing part can be made sufficiently large, so the tip shape of the condensing part is molded. It can be expected to be easier and easier to handle during assembly.

[Condenser of Second Configuration]
Next, the condensing device 2 of the second configuration form will be described from the basic configuration of the condensing optical element with reference to FIGS. 15 and 16. Here, FIG. 15 is a schematic diagram for explaining a basic configuration of the condensing optical element 20II in the condensing device 2, and FIG. 16 is a relationship between incident light condensed by the condensing lens and incident and a condensing reflection surface. It is explanatory drawing (side view) for demonstrating. In addition, the same number is attached | subjected to the component similar to the condensing apparatus 1 (1a, 1b, 1c) of the 1st structure form mentioned already, and duplication description is abbreviate | omitted.

  In FIG. 15, light collected by the condenser lens 10 and incident on the condensing optical element 20II is reflected by the condensing reflection surface 35 of the optical structure 30 formed on the condensing optical element and propagates through the element. The scene to do is drawn schematically.

  The condensing optical element 20II includes an upper surface 22 that transmits incident light that is collected by the condensing lens 10 and is incident on the base material 21, a lower surface 23 that extends parallel to the upper surface, and is disposed between the upper surface 22 and the lower surface 23. A condensing reflection surface 35 provided to intersect the optical axis LA of incident light and reflecting incident light and an exit surface 26 provided on the opposite side of the condensing reflection surface 35 are configured. In the illustrated form, an optical structure 30 protruding inward of the base material 21 is provided on the lower surface 23 of a transparent plate-like or sheet-like condensing optical element, and a condensing reflection surface 35 is formed on the inner surface thereof. Indicates.

  The optical structure 30 is a hollow structure that is recessed in the lower surface 23 of the base material 21 (in other words, a projecting hollow structure projecting inward from the lower surface 23 to the base material 21). As shown in FIG. 16 is a perspective view of the optical structure alone viewed from diagonally above, the optical structure 30 includes a condensing reflection surface 35 extending obliquely upward from the lower surface 23 and a condensing reflection surface extending upward from the lower surface 23. The rear surface 36 is connected to 35, and the side surfaces 32, 33 are connected to the condensing / reflecting surface 35 and the rear surface 36.

  The condensing reflection surface 35 is formed in a curved surface shape that suppresses the spread angle after reflection of incident light incident at a predetermined convergence angle or divergence angle by the condensing lens 10. The converging angle or divergence angle of the incident light incident on the condensing / reflecting surface 35 includes the focal length f and effective diameter R of the condensing lens 10, the refractive index n of the base material 21, and the position of the condensing / reflecting surface 35 and the focal position. It depends on the relationship.

  The incident light incident on the condensing reflection surface 35 is focused light. When the focal position is located below the condensing reflection surface 35, the incident light becomes divergent light. It is when it is located above 35. The condensing reflection surface 35 of the condensing optical element 20II suppresses the divergence angle after reflection of incident light incident at a predetermined focusing angle or divergence angle as described above (incident light incident at a predetermined focusing angle or divergence angle). It is formed in a curved surface shape such as collimating.

  In the present configuration, as shown in FIG. 16, the focal position of the incident light is set below the converging / reflecting surface 35 and the condensing light is incident, and the condensing / reflecting surface 35 is a sphere having a radius of curvature r. The structure made into the convex curved surface which cut out a part of is shown. With this configuration, incident light that has entered the base material 21 from the upper surface 22 through the condenser lens 10 and has entered the condensing / reflecting surface 35 at a predetermined converging angle has its divergence angle suppressed by the condensing / reflecting surface 35. The reflected light propagates through the condensing optical element 20 and is guided to the exit surface 26.

Here, the incident light that converges and enters the condensing reflection surface 35 via the condensing lens 10 is incident on the light ray b that enters the condensing reflection surface 35 through the optical axis LA (the center of the condensing lens 10). The angle θ (for convenience, referred to as “optical axis incident angle”) θ _LA and the incident angle of the light beam a incident on the upper part of the condensing reflection surface 35 through a position away from the optical axis LA (the outer periphery of the condensing lens) And the incident angle of the light beam c incident on the lower part of the condensing reflection surface 35 are different from each other.

  In the condensing optical element 20, the minimum incident angle of the light beam that is collected and incident on the condensing reflection surface 35 is set to be equal to or greater than the total reflection angle of the condensing reflection surface 35. That is, depending on the incident parameters such as the numerical aperture NA of the condenser lens 10, the refractive index n of the base material 21, the position shape of the condensing reflection surface 35 (the radius of curvature r of the spherical surface, the position of the spherical center with respect to the focal position of the condensing lens). The minimum incident angle of light incident on the condensing reflection surface 35 is set to be equal to or greater than the total reflection angle. Specifically, the refractive index n of the base material 21 and the numerical aperture NA of the condenser lens 10 are set to predetermined values, and the minimum incident angle of light incident at a predetermined focusing angle by the condenser lens 10 is The position shape of the condensing reflection surface 35 can be set so as to be equal to or greater than the total reflection angle.

  Further, the refractive index n of the base material 21 and the position shape of the condensing reflection surface 35 are set to predetermined values so that the minimum incident angle of light incident at a predetermined converging angle is equal to or greater than the total reflection angle on the condensing reflection surface 35. The numerical aperture NA of the condenser lens 10 (generally, the focal length f and effective diameter R of the condenser lens 10) can be set. Alternatively, the numerical aperture NA of the condensing lens 10 and the position shape of the condensing reflection surface 35 are set to predetermined values so that the minimum incident angle of light incident at a predetermined converging angle is equal to or greater than the total reflection angle on the condensing reflection surface 35. In addition, the refractive index n of the base material 21 can be set, specifically, by selecting the material of the base material 21 or the additive to be doped into the base material.

  Further, in the condensing optical element 20, the converging reflection surface 35 suppresses the divergence angle and reflects the light, and the minimum incident angle of light incident on the lower surface 23 and the upper surface 22 is equal to or greater than the total reflection angle on these surfaces. Set to These are also set so that the minimum incident angle of the light beam incident on the upper surface and the lower surface from the condensing reflection surface 35 is equal to or greater than the total reflection angle according to the incident parameters. Therefore, the incident parameters such as the position shape of the condensing reflection surface 35, the numerical aperture NA of the condensing lens 10 and the refractive index n of the condensing optical element 20 are totally reflected on the condensing reflection surface 35, the upper surface 22 and the lower surface 23. It is set to satisfy the conditions.

  The case where a film such as a protective film having a refractive index different from that of the base material 21 is formed on the upper surface 22 or the lower surface 23 is the same as that of the light condensing device of the first configuration described above. If the inclination angle of the light incident on the substrate 21 is equal to or greater than the total reflection angle at the interface between the substrate 21 and air, the total reflection condition is satisfied at least at the interface between the film and air, and the incident light is collected into the condensing optical element. It is confined inside 20.

  The light totally reflected by the condensing reflection surface 35 is totally reflected by the upper surface 22 and the lower surface 23, propagates in the optical element 20 in the x-axis direction, and is extracted from the emission surface 26. The exit surface 26 is formed along the yz plane, and the end surface is polished and AR-coated. The light that has propagated through the optical element 20 and entered the exit surface 26 is reflected by the exit surface 26. The light is emitted without being incident on the photoelectric conversion element 5.

  The basic configuration (unit configuration) of the condensing optical element 20II of the second configuration form has been described above. The condensing unit 20s of the condensing optical element 20II (20A, 20B, 20C) corresponds to the condensing lens 10 (10A, 10B, 10C) including unit condenser lenses of m rows × n columns, and m rows × n. It has a condensing reflection surface 35 in a row. FIG. 17 is a perspective view of the condensing unit 20s (condensing optical element 20C) as viewed obliquely from above. FIG. 18A shows an enlarged perspective view of the optical structure 30, and FIGS. 18B and 18C show examples of the alignment configuration of reflected light by the condensing reflection surface (both conceptual views in plan view). . 18B and 18C correspond to a 10 × 10 condensing lens, and 10 rows × 10 columns (B1 to B10 rows × A1 to A10 columns) on the lower surface side of the substrate 21. ) Of the optical structure 30 formed in a matrix shape is illustrated, and each optical structure 30 that is visible from the upper surface 21 side through the base material 21 is indicated by a solid line.

  As shown in FIG. 17, the condensing unit 20 s of the condensing optical element 20 </ b> II has 10 rows × 10 columns = 100 optical structures 30 formed in a matrix on the lower surface side of the base material 21. It has a rectangular plate shape. In the condensing optical element 20II, the light reflected by the condensing reflection surface of the first optical structure 30 located on the upstream side is not blocked by the second optical structure 30 located on the downstream side and is emitted to the emission surface 26. Configured to head.

As the means, the condensing portions 20s ₁ and 20s ₂ of the first configuration example and the second configuration example are such that the reflected light reflected by the condensing reflection surface of the first optical structure 30 is adjacent to the first optical structure. Then, it is configured to propagate through the side of the second optical structure 30 formed on the exit surface side. Such an alignment method of reflected light is referred to as a “lateral path method” for convenience. FIGS. 18B and 18C show two configuration examples of this horizontal path method.

In the first configuration example shown in FIG. 18B, the light condensing unit 20s ₁ has the _first direction of the A1 column as indicated by the arrow of the orientation direction of the reflected light by the optical structures 30, 30,. Reflected light reflected by the reflecting surface of the optical structure 30 and reflected light reflected by the reflecting surface of the second optical structure 30 in the A2 row are formed on the exit surface 26 side adjacent to the second optical structure. Is configured to propagate through the same side (upper side in the figure) side with respect to the third optical structure 30 in the A3 row.

  Specifically, the optical structure 30 shown in FIG. 18A is formed by rotating the optical structure 30 around the z-axis by the minute angle α in the same direction, and the reflected light reflected by each condensing reflection surface 35 is the x-axis. However, the light can be emitted from the emission surface 26 at a slight angle α. The minute angle α can be set based on the spread angle of the reflected light reflected by the condensing reflection surface 35 and the arrangement pitch of the adjacent optical structures.

  FIG. 18B shows a configuration example in which B1 to B10 rows and A1 to A10 columns are formed in a square matrix shape orthogonal to each other, but B1 to B10 rows are inclined by a minute angle α (for example, FIG. 18). In (b), lines B1 to B10 are formed so that the right end side inclined by a minute angle α is shifted downward in the drawing), and the reflected light reflected by each condensing reflection surface 35 is an emission surface along the x axis. 26 may be configured to emit from 26.

The condensing optical elements 20A, 20B, and 20C having the condensing unit 20s ₁ having such a configuration are provided corresponding to the condensing lenses 10A, 10B, and 10C. At this time, the condensing optical elements 20A, 20B, and 20C are arranged such that the condensing reflection surfaces 35, 35, 35... Do not overlap vertically, and the exit surfaces 26 of the respective condensing optical elements are arranged vertically. A condensing device 2a of one configuration example is configured.

  Specifically, as illustrated in FIG. 7 and the like, in the condensing optical elements 20A and 20B, the base 21 is extended in the x-axis direction to form a flat light guide portion 20t, and the condensing optics. The condensing optical element 20B is placed on the light guide 20t of the element 20A, and the condensing optical element 20C is placed on the light guide 20t of the condensing optical element 20B. The exit surfaces 26, 26, and 26 of the condensing optical elements 20A, 20B, and 20C are arranged side by side, and an output unit 27 in which these exit surfaces are aggregated is formed (see FIGS. 6 and 12).

  Note that the height positions in the z-axis direction of the respective condensing reflection surfaces 35 of the condensing optical elements 20A, 20B, and 20C are different by the thickness of the light guide portion 20t, as described in the first configuration. This is the same as the light collecting devices 1a and 1b. That is, a condensing lens having the same focal length is used as the condensing lenses 10A, 10B, and 10C, and the height positions of the condensing lenses 10A, 10B, and 10C are different according to the difference in the height position of the condensing reflection surface 35. Configuration (see FIG. 6) or a configuration using condensing lenses with different focal lengths corresponding to the difference in height position of the condensing reflection surface 35 as the condensing lenses 10A, 10B, and 10C (see FIG. 12). Any of the above can be applied.

In the second configuration example shown in FIG. 18C, the condensing unit 20s ₂ has the first direction of the A1 column as indicated by the arrow of the orientation direction of the reflected light by the optical structures 30, 30,. Reflected light reflected by the reflecting surface of the optical structure 30 and reflected light reflected by the reflecting surface of the second optical structure 30 in the A2 row are formed on the exit surface 26 side adjacent to the second optical structure. The third optical structure 30 of the A3 row is configured to propagate through the sides on the opposite side (upper side and lower side in the drawing).

  Specifically, the optical structure 30 shown in FIG. 18A is formed by sequentially rotating the optical structure 30 around the z axis in the opposite direction by a minute angle β, and the reflected light reflected by each condensing reflection surface 35 is the x axis. In this case, the light can be emitted from the emission surface 26 with an inclination of a small angle β. The minute angle β can be set based on the spread angle of the reflected light reflected by the condensing reflection surface 35 and the arrangement pitch of the adjacent optical structures, similarly to the minute angle α described above. On the other hand, according to this configuration example, the pitch between rows can be reduced.

The condensing optical elements 20A, 20B, and 20C having the condensing unit 20s ₂ having such a configuration are provided corresponding to the condensing lenses 10A, 10B, and 10C. At this time, the condensing optical elements 20A, 20B, and 20C are arranged such that the condensing reflection surfaces 35, 35, 35... Do not overlap vertically, and the exit surfaces 26 of the respective condensing optical elements are arranged vertically. A condensing device 2b of two configuration examples is configured.

  In the condensing optical elements 20A and 20B, the base 21 is extended in the x-axis direction to form a flat light guide 20t, and the condensing optical element 20B is formed on the light guide 20t of the condensing optical element 20A. Is placed, and the condensing optical element 20C is placed on the light guide portion 20t of the condensing optical element 20B. The exit surfaces 26, 26, and 26 of the condensing optical elements 20A, 20B, and 20C are arranged side by side, and an output unit 27 in which these exit surfaces are aggregated is formed (see FIG. 6, FIG. 12, etc.). . The relationship between the height position in the z-axis direction of each of the condensing reflection surfaces 35 of the condensing optical elements 20A, 20B, and 20C and the focal length of the condensing lenses 10A, 10B, and 10C is as follows. Same as 2a.

According to the condensing optical element 20II provided with such lateral path type condensing portions 20s ₁ and 20s ₂ , a large number of optical structures 30 are integrally formed on the rectangular plate-like base material 21, and each of the optical structures has an optical structure. The reflected light whose divergence angle is suppressed by the condensing reflection surface 35 is taken out to the emission surface 26 through the side without being blocked by the adjacent optical structure. For this reason, according to the condensing apparatuses 2a and 2b provided with the condensing optical element 20II having such a configuration, the condensing efficiency can be increased with a simple and thin configuration. Further, since the light condensed by the plurality of condensing optical elements 20 can be taken out from one output unit 27, the photoelectric conversion element 5, the photothermal conversion device, and the like can be collectively arranged, and the device can be downsized. In addition, the degree of freedom in device design can be improved.

Next, the light collecting portion 20s ₃ of the third configuration example will be described with reference to FIG. 19. FIG. 19 is a conceptual diagram of an xz cross section viewed from the y-axis direction with respect to an arbitrary row in a light condensing unit in which optical structures 30, 30.

In the condensing unit 20s ₃ of the third configuration example in the condensing optical element 20II of the second configuration form, the reflected light reflected by the first optical structure 30 located on the upstream side is emitted from the first optical structure. It is configured to propagate through the second optical structure 30 formed on the 26th side. Hereinafter, such an alignment method of reflected light is referred to as a “longitudinal pass method”.

As shown in FIG. 19, the vertical path type condensing unit 20 s ₃ has reflected light reflected by the condensing reflection surface 35 of the first optical structure 30 with its divergence angle being suppressed at the lower surface 23 and the upper surface 22. In the process of sequentially being totally reflected and propagated to the exit surface 26, it is configured to propagate in the exit surface direction through the second optical structure 30 adjacent to the exit surface side.

  At this time, there are various types of configurations as to what kind of route is propagated in the substrate 21 before reaching the emission surface 26, and an appropriate configuration can be adopted. For example, as shown in FIG. 19, in addition to a form in which the optical structures 30, 30,. Can be set as appropriate according to the number of rows and arrangement pitch of the optical structures 30, the spread angle of the reflected light by the condensing reflection surface 35, the thickness of the substrate 21, and the like. .

Converging optical element 20A having a collection portion 20s ₃ having such a configuration, 20B, 20C is, the condenser lens 10A, 10B, provided in correspondence to 10C. At this time, the condensing optical elements 20A, 20B, and 20C are arranged such that the condensing reflection surfaces 35, 35, 35... Do not overlap vertically, and the exit surfaces 26 of the respective condensing optical elements are arranged vertically. A condensing device 2c having three configuration examples is configured.

  In the condensing optical elements 20A and 20B, the base 21 is extended in the x-axis direction to form a flat light guide 20t, and the condensing optical element 20B is formed on the light guide 20t of the condensing optical element 20A. Is placed, and the condensing optical element 20C is placed on the light guide portion 20t of the condensing optical element 20B. The exit surfaces 26, 26, and 26 of the condensing optical elements 20A, 20B, and 20C are arranged side by side, and an output unit 27 in which these exit surfaces are aggregated is formed (see FIGS. 6 and 12). The relationship between the height position in the z-axis direction of each of the condensing reflection surfaces 35 of the condensing optical elements 20A, 20B, and 20C and the focal length of the condensing lenses 10A, 10B, and 10C is the first configuration example and the second configuration. This is the same as the light collecting devices 2a and 2b in the example.

According to the condensing optical element 20II provided with the condensing part 20s ₃ of such a vertical path method, a large number of optical structures 30 are integrally formed on the rectangular plate-like base material 21, and the converging reflections of the optical structures are respectively provided. The reflected light whose divergence angle is suppressed by the surface 35 is taken out to the exit surface 26 through the upper side without being shielded by the adjacent optical structure. For this reason, according to the condensing apparatus 2c of such a structure, condensing efficiency can be made high with a simple and thin structure. Further, since the light condensed by the plurality of condensing optical elements 20 can be taken out from one output unit 27, the photoelectric conversion element 5, the photothermal conversion device, and the like can be collectively arranged, and the device can be downsized. In addition, the degree of freedom in device design can be improved.

  The condensing device may be configured by appropriately combining the horizontal path type condensing optical element and the vertical path type condensing optical element described above. Further, the radius of curvature of the condensing reflection surface 35 may be different depending on the formation position (for example, column position, row position, etc.) of the optical structure 30 in the condensing optical element 20.

[Example]
Next, a more specific embodiment in the case where sunlight is collected by a light collecting device will be described with reference to simulation results shown in FIGS.

  In the simulation, the condensing lens 10 (10A, 10B, 10C) and the condensing optical element 20 (20A, 20B, 20C) are composed of PMMA (polymethyl methacrylate) for the condensing device 1 of the first configuration form, and the wavelength The case of collecting sunlight of 350 nm to 1100 nm was performed using a ray tracing tool widely used by optical designers. At this time, the refractive index of PMMA was obtained by linearly interpolating the values in the table shown in FIG. 20, and the spectral density of incident light was based on the sunlight spectrum shown in FIG.

Further, regarding the condensing devices 1a and 1c, the thickness of the condensing optical elements 20A, 20B, and 20C is 1 mm, the focal length f of each unit condensing lens constituting the condensing lenses 10A, 10B, and 10C is 20 mm. an inclined angle theta ₂₅ = 52 degrees of the reflecting surface 25, and the viewing angle of the sunlight and 0.52 degrees.

  Under the above common conditions, a ray-trace simulation result when sunlight is incident on a condensing device including a pair of condensing lens 10 and condensing optical element 20I (condensing unit 20s). This is illustrated in FIG. 22 and FIG. FIG. 22 is a simulation result when the light collecting device is viewed from the y-axis direction (side), and FIG. 23 is a simulation result when the light collecting device is viewed obliquely from above, showing the relationship between the unit condensing lens and the element unit of the light converging unit. ing. Hereinafter, an embodiment of the condensing device 1 including the three condensing lenses 10 and the condensing optical element 20I will be described.

[First embodiment]
The simulation results when sunlight is incident on the light collecting apparatus 1a of the first configuration example described above (see FIGS. 5 to 7) are shown in FIGS. At this time, the interface between the upper surface 22 of the condensing optical element 20A and the lower surface 23 of the condensing optical element 20B, and the interface between the upper surface 22 of the condensing optical element 20B and the lower surface 23 of the condensing optical element 20C are overlapped with each other. Are not coupled together, and there is an air layer at each interface, that is, the condensing optical elements 20A, 20B, and 20C are simply placed one above the other.

  FIG. 24A shows simulation data of the condensing device 1a viewed from the side (y-axis direction), and FIG. 24B shows the condensing optical elements 20A, 20B, and 20C from above (condensing lens side). It is the simulation result that I saw. The numerical values 1, 11, 21, and 30 shown in FIG. 24A are obtained when the number of condensing reflection surfaces 25 in the condensing optical elements 20A, 20B, and 20C is given in order from the upstream side (20A side). 1-10 are the condensing optical element 20A, 11-20 are the condensing optical element 20B, and 21-30 are the condensing reflective surfaces of the condensing optical element 20C.

  25 (a), (b), and (c) are partially enlarged views of simulation results when the condensing optical elements 20A, 20B, and 20C are viewed from the side, respectively, and FIG. FIG. 25B is a partially enlarged view of the distal end portion of the condensing optical element 20A that does not overlap with the optical optical element. FIG. 25B is a front end portion of the condensing optical element 20B that overlaps the light guide portion 20t of the condensing optical element 20A. FIG. 25C is a partially enlarged view of the distal end portion of the condensing optical element 20C that overlaps the light guide portion 20t of the condensing optical element 20A and the condensing optical element 20B. The numerical values 1 to 4, 11 to 14, and 21 to 24 shown in FIG. 25 are the column numbers of the condensing / reflecting surface 25 as described above.

  FIG. 26 shows the illuminance distribution of the light collected by the light collecting device 1a and emitted from the output unit 27. The horizontal axis in FIG. 26 is the position in the z-axis direction (distance from the lower surface), and the vertically divided regions divided into three correspond to the exit surfaces 26, 26, 26 of the respective condensing optical elements 20A, 20B, 20C. The vertical axis in FIG. 26 is the position in the y-axis direction (see FIGS. 1, 5 and the like), and the output surface having a width of 100 mm is divided into 50 by 10 rows of element units. The regions divided into 3 × 50 = 150 meshes are classified into 10 levels of illuminance (number of light rays / mesh) according to the number of light rays passing through each region, and are shown in FIG. 26 as the illuminance distribution of the number of light rays / mesh. It is shown according to the gray scale of light and shade. The asterisk (*) shown in the gray scale indicates the width of the illuminance of the simulation result in this example.

  From FIG. 24, in the condensing part 20s of each condensing optical element, the light rays condensed and incident on the condensing reflection surfaces 25, 25... It can be seen that the first side surface 24a and the second side surface 24b are totally reflected and guided in the x-axis direction, and the light beam density increases toward the exit surface 26 side. It can also be seen that the total reflection condition is satisfied on each of the surfaces, and the light beam reflected into the element by the condensing reflection surface 25 is extracted to the exit surface 26 with almost no leakage from the condensing optical element 20.

  From FIG. 25, the light incident on the condensing optical elements 20A, 20B, and 20C is totally reflected on the upper surface 22 and the lower surface 23 of each condensing optical element, guided in the x-axis direction, and directed toward the emission surface 26. It can be seen that the condensing optical elements 20A, 20B, and 20C act as independent condensing optical elements.

  From FIG. 26, in the output part 27, the illuminance differs on the exit surface 26 of the condensing optical element 20C depending on the position in the y-axis direction, and the illuminance width is wide. On the exit surface 26 of the condensing optical element 20B, y It can be seen that the width of the illuminance in the axial direction is narrowed, and the light exit surface 26 of the condensing optical element 20A is substantially uniform with an intermediate illuminance regardless of the position in the y-axis direction.

  On the exit surface 26 of the condensing optical element 20C, the direction in which the illuminance is high (the direction in which the numerical value in the y-axis direction is small in FIG. 26) is the condensing reflection surface 25, the first side surface 24a, and the second side surface 24b. It coincides with the tilt direction. This is understood because the light beam density increases in the inclined direction in each condensing unit 20s (see FIG. 24b). On the other hand, the width of the illuminance in the y-axis direction is narrowed on the exit surface 26 of the condensing optical element 20B, and the illuminance is almost uniform on the exit surface 26 of the condensing optical element 20A regardless of the position in the y-axis direction. The light beams deflected in the tilt direction are repeatedly reflected on the first side surface 24a, the second side surface 24b, and the left and right side surfaces of the light guide unit 20t of each element unit, so that the light beam densities in various directions are equalized. It is understood that.

[Second Embodiment]
Next, in the condensing device 1a of the first configuration example described above, the condensing optical elements 20A, 20B, and 20C that overlap vertically are arranged in close contact with each other, and matching oil or an optical adhesive material is dropped on the overlapping portion. The light collecting optical elements are integrally joined. In this state, simulation results when sunlight is incident through the condenser lenses 10A, 10B, and 10C are shown in FIGS. In addition, the numerical value of 1-4, 11-14, 21-24 added in a figure is the column number of the condensing reflective surface 25 similarly to the Example mentioned above.

  FIG. 27 corresponds to FIG. 24, FIG. 27 (a) shows a simulation result when the condensing device 1a is seen from the side, and FIG. 27 (b) shows the condensing optical elements 20A, 20B, and 20C as seen from above. It is a simulation result. 28 corresponds to FIG. 25, FIG. 28 (a) is a partially enlarged view of the tip portion of the condensing optical element 20A that does not overlap with other condensing optical elements, and FIG. 28 (b) is the condensing optics. FIG. 28C is a partially enlarged view of the tip portion of the condensing optical element 20B overlapping with the light guide portion 20t of the element 20A, and FIG. 28C shows the condensing optical element 20C overlapping with the light guide portion 20t of the condensing optical elements 20A and 20B. It is the elements on larger scale of the front-end | tip part.

  FIG. 29 corresponds to FIG. 26 and shows the illuminance distribution of the light condensed by the condensing device 1 a and emitted from the output unit 27. 29, the vertical axis and the horizontal axis are the same as those in FIG. 26, the vertical axis is the position in the y-axis direction, and the horizontal axis is the position in the z-axis direction (the exit surfaces 26, 26, and 20C of the condensing optical elements 20A, 20B, and 20C). 26). Then, the regions divided into 3 × 50 = 150 meshes are classified into 10 levels of illuminance (number of light beams / mesh) according to the number of light beams passing through each region, and are shown in FIG. 29 as the illuminance distribution of the number of light beams / mesh. It is shown according to the gray scale of light and shade. The asterisk (*) shown in the gray scale indicates the width of the illuminance of the simulation result in this example.

  From FIG. 27, in the condensing part 20s of each condensing optical element, the light rays condensed and incident on the condensing reflection surfaces 25, 25... It can be seen that the light is totally reflected by the first side surface 24a and the second side surface 24b and guided in the x-axis direction, and the light density increases toward the exit surface 26 side. It can also be seen that the reflected light is extracted to the exit surface 26 with almost no leakage from the condensing optical element 20.

  From FIG. 28A, in the condensing part 20s of the condensing optical element 20A having no overlapping part, the light reflected by the condensing reflection surface 25 is totally reflected by the upper surface 22 and the lower surface 23 of the condensing part. You can see how it is guided in the x-axis direction. On the other hand, from FIG. 28B, in the region where the condensing part 20s of the condensing optical element 20B and the light guiding part 20t of the condensing optical element 20A overlap, the condensing reflection surface 25 of the condensing optical element 20B is used. Part of the reflected light enters the light guide 20t of the condensing optical element 20A through the interface, and part of the light propagating through the light guide 20t of the condensing optical element 20A passes through the interface. It is recognized that the light is totally reflected on the upper surface of the condensing optical element 20B. Similarly, from FIG. 28C, in the region where the condensing unit 20s of the condensing optical element 20C and the light guiding unit 20t of the condensing optical elements 20A and 20B overlap, the condensing reflection of the condensing optical element 20C. A part of the light reflected by the surface 25 enters the light guide 20t of the condensing optical elements 20B and 20A through the interface, and is a part of the light propagating through the light guide 20t of the condensing optical elements 20B and 20A. It is recognized that the part is totally reflected by the upper surface of the condensing optical element 20C through the interface.

  From FIG. 29, it can be seen that, as an overall trend, the output unit 27 increases the illuminance in the direction in which the numerical value in the y-axis direction decreases. In other words, the illuminance is high in the direction in which the numerical value in the y-axis direction decreases with respect to any of the exit surfaces 26, 26, 26 of the condensing optical elements 20A, 20B, 20C. As discussed in the first embodiment, this is because the direction in which the illuminance is high coincides with the inclination directions of the condensing reflection surface 25, the first side surface 24a, and the second side surface 24b. It is understood that the light density toward the tilt direction increases.

  On the other hand, as apparent from the comparison between FIG. 29 and FIG. 26, in the present configuration example, the exit surface 26 of the condensing optical element 20A, the exit surface 26 of the condensing optical element 20B, and the condensing optical element 20C. The illuminance distribution in the y-axis direction is almost the same on the exit surface 26, and the illuminance in the z-axis direction is constant at any position. Also, the illuminance width (variation) between the high illuminance portion and the low illuminance portion is implemented, as can be seen by comparing the illuminance width indicated by * in the gray scale of FIG. 29 with the illuminance width of FIG. It can be seen that it is smaller than Example 1. This is because the light beam deflected as described above is reflected by the first side surface 24a, the second side surface 24b, and the left and right side surfaces of the light guide unit 20t, and the overlapping of the plurality of condensing optical elements. It is understood that the effect of the three-dimensional propagation of light rays through the interface in the part synergistically acts, and the light density toward various directions is equalized three-dimensionally.

[Third embodiment]
Next, in the condensing device 1c of the third configuration example described above (see FIGS. 13 and 14), the condensing optical elements 20A, 20B, and 20C that overlap vertically are arranged in close contact with each other and matched to the overlapping portion. 30 to 32 show simulation data when oil or an optical adhesive is dropped and the three condensing optical elements are integrally joined, and sunlight is incident through the condensing lenses 10A, 10B, and 10C. Show. Numerical values 1 to 4, 11 to 14, and 21 to 24 added in the drawing are column numbers of the condensing reflection surface 25 as in the above-described embodiments.

  FIG. 30 corresponds to FIG. 24 and FIG. 27, FIG. 30 (a) shows a simulation result when the condensing device 1c is viewed from the side, and FIG. 30 (b) shows the condensing optical elements 20A, 20B, and 20C. It is the simulation result seen from the top. FIG. 31 corresponds to FIG. 25 and FIG. 28, and FIG. 31 (a) is a partial enlarged view of the tip portion of the condensing optical element 20 </ b> A that does not overlap with other condensing optical elements, and (b) condensing optics. FIG. 7C is a partial enlarged view of the tip portion of the condensing optical element 20B overlapping with the light guide portion 20t of the element 20A, and FIG. It is a partial enlarged view.

  FIG. 32A corresponds to FIG. 26 and FIG. 29, and shows the illuminance distribution of the light collected by the light collecting device 1 c and emitted from the output unit 27. The vertical axis and horizontal axis of FIG. 32A are the same as those of FIGS. 26 and 29, and the asterisk * shown in the gray scale indicates the width of the illuminance of the simulation result in this example. FIG. 32B shows the illuminance distribution in the case where the condensing device 1c is composed of two sets of condensing lenses 10 (10B, 10C) and condensing optical elements 20 (20B, 20C).

  From FIG. 30, in the condensing part 20s of each condensing optical element, the light rays condensed and incident on the condensing reflection surfaces 25, 25... It can be seen that the first side surface 24a and the second side surface 24b are totally reflected and guided in the x-axis direction, and the light beam density increases toward the exit surface 26 side. It can also be seen that the light beam reflected into the element by the condensing reflection surface 25 is extracted to the emission surface 26 with almost no leakage from the condensing optical element 20. 30B is compared with FIGS. 24B and 27B, it can be seen that the light density and the emission direction of the light emitted from the output unit 27 are equalized.

  The same situation as in FIGS. 31 to 27 is recognized. That is, from FIG. 31A, in the condensing unit 20s of the condensing optical element 20A that does not overlap with other condensing optical elements, the light reflected by the condensing reflection surface 25 is the upper surface 22 of the condensing unit. It can be seen that the light is totally reflected by the lower surface 23 and guided in the x-axis direction. Further, from FIG. 31B, in the region where the condensing part 20s of the condensing optical element 20B and the light guiding part 20t of the condensing optical element 20A overlap, and from FIG. 31C, the condensing optics. In the region where the light condensing unit 20s of the element 20C and the light guiding unit 20t of the condensing optical elements 20A and 20B overlap, a part of the light reflected by the condensing reflection surface 25 passes through the interface and collects light in the lower layer. A state in which a part of the light that enters the light guide 20t of the optical element and propagates through the light guide 20t of the lower-layer condensing optical element is totally reflected by the upper surface of the uppermost condensing optical element through the interface Is recognized.

  FIG. 32A shows that the illuminance distribution in the output unit 27 is substantially uniform. That is, none of the exit surfaces 26, 26, 26 of the condensing optical elements 20A, 20B, 20C has a tendency of illuminance change depending on the y-axis direction and the z-axis direction, and is indicated by * a in gray scale. As is clear from the illuminance width shown in FIGS. 26 and 29, it can be seen that the illuminance width (variation) between the high illuminance portion and the low illuminance portion is extremely small.

  This is because the condensing reflection surfaces 25, the first side surface 24a, and the second side surface 24b are formed so that the inclination directions of the condensing optical elements 20A and 20C and the condensing optical element 20B are axisymmetric with respect to the x axis. The effect of the existence of the light beam groups whose deflection directions are opposite to each other (see FIG. 30B) and the left and right sides of the first side surface 24a, the second side surface 24b, and the light guide unit 20t of each element unit. The effect of reflection on the side surface and the effect of three-dimensional propagation of light rays through the interface at the overlapping part of multiple converging optical elements work synergistically, and the light density toward various directions is further three-dimensional. It is understood to be equalized.

  This is because the illuminance distribution tends to be constant even in the case where the condenser lens 10 (10B, 10C) and the condenser optical element (20B, 20C) shown in FIG. Therefore, it is understood that the illuminance width indicated by the mark * b is narrower than the illuminance width of the triplet second embodiment.

[Extraction method of light energy from output section]
Next, a method for extracting energy of light emitted from the output unit 27 in the light collecting apparatuses 1 and 2 will be briefly described with reference to FIG. FIG. 33A is a conceptual diagram of a configuration example in which light collected by the condensing optical elements 20A, 20B, and 20C is extracted as it is from the output unit 27 and used as light energy. Here, the light emitted from the emission surface 26 of the condensing optical element 20 is condensed through the cylindrical lens 91, the condensing rod 92, etc., and the condensed light is guided to a desired position by the optical fiber 93. The configuration is illustrated.

  Thereby, the light condensed by the condensing devices 1 and 2 can be used in a desired place away from the condensing device. For example, the photoelectric conversion element 5 can be installed in a unit box provided with a cooling device for preventing overheating of the photoelectric conversion element, and can be transmitted through the optical fiber 93 into the unit box. For example, it is possible to transmit the light collected by the light collecting devices 1 and 2 through the optical fiber 93 and use it in a vegetable factory or the like far away from the light collecting device. The condensing devices 1 and 2 have a plurality of condensing lenses 10 and condensing optical elements 20, and the light condensed by them is taken out from an output unit 27 in which a plurality of emission surfaces 26 are arranged vertically. Therefore, the light collection efficiency can be improved with a simple device configuration, and light energy such as sunlight can be used efficiently.

  FIG. 33B is a conceptual diagram in the case where light collected by the condensing optical elements 20A, 20B, and 20C and emitted from the output unit 27 is converted into electric energy or heat energy and extracted. This figure shows a configuration example in which the photoelectric conversion element 5 is coupled to the emission end of the condensing optical element 20 and is taken out as electric energy. The condensing devices 1 and 2 have a plurality of condensing lenses 10 and condensing optical elements 20, and the light condensed by them is taken out from an output unit 27 in which a plurality of emission surfaces 26 are arranged vertically. Therefore, the power of light incident on the photoelectric conversion element 5 can be increased with a simple device configuration, and light energy such as sunlight can be efficiently used. Furthermore, according to the configuration shown in the second and third embodiments, the power density (illuminance distribution) of light incident on each part of the photoelectric conversion element 5 can be equalized, and the photoelectric conversion element 5 The conversion efficiency into electrical energy can be greatly improved.

  In the case of a photothermal conversion device that takes out the light collected by the condensing optical elements 20A, 20B, and 20C and emitted from the output unit 27 as heat energy, as a photothermal conversion element that converts light energy into heat energy, For example, a heat pipe with a light absorber is preferably used.

  In the embodiment, for the sake of simplicity of explanation, the condensing optical element is illustrated as a sheet-like or plate-like form in which two or three layers are stacked, and in order to explain the action of the condensing optical element, the substrate 21 However, the present invention is not limited to these configuration forms and configuration examples. For example, the condensing optical element 20 may have a form in which four or more layers (20A, 20B, 20C, 20D...) Are overlapped, and the base material 21 is configured by appropriately selecting various resin materials, inorganic materials, and the like. can do.

  As described above, in the condensing devices 1 and 2, there are a plurality of sets of the condensing lens 10 and the condensing optical element 20, and the light condensed by these includes the condensing reflection surface 25, the upper surface 22, and the lower surface. 23, the light is totally reflected by the first side surface 24a and the second side surface 24b, and the output surface 26 is taken out from the output unit 27 arranged vertically. Therefore, according to the condensing apparatuses 1 and 2 of the aspect of the present invention, it is possible to provide a new condensing apparatus that can efficiently use light energy such as sunlight with a thin and simple configuration. In addition, the light condensing device 1 such as the photovoltaic power generation device PVS and the photothermal conversion device has a small thickness in the optical axis direction and is small and lightweight, and is suitable as a new photovoltaic power generation device or a solar heat collecting device.

  As described above, various embodiments and modifications have been described, but the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

The disclosure of the following priority application is hereby incorporated by reference.
Japanese Application 2010 No. 255350 (November 15, 2010)

Claims (13)

A first condensing optical element that is formed of a first condensing lens, a transparent material, and that guides incident light that is condensed by the first condensing lens and incident thereon, a second condensing lens, and a transparent material And a second condensing optical element that guides incident light that is condensed by the second condensing lens and is incident,
The first condensing optical element and the second condensing optical element respectively include an upper surface that transmits the incident light, a lower surface that extends opposite to the upper surface, and the incident light between the upper surface and the lower surface. A reflecting surface provided to intersect the optical axis and reflecting the incident light; and an exit surface provided on the opposite side of the reflecting surface;
The reflecting surface of the first condensing optical element and the reflecting surface of the second condensing optical element do not overlap vertically, and the exit surface of the first condensing optical element and the second condensing optical element The first condensing optical element and the second condensing optical element are arranged so as to overlap each other so that their emission surfaces are aligned vertically.
The light collected by the first condenser lens and the second condenser lens and reflected by the reflecting surface is emitted from the first condenser optical element and the second condenser optical element. Concentrator configured to be guided to a surface.   The reflecting surface is set so that a minimum incident angle of light incident on the reflecting surface at a predetermined focusing angle or diverging angle by the condenser lens is equal to or greater than a total reflection angle at the interface between the reflecting surface and air. The light collecting device according to claim 1.   The condensing device according to claim 1, wherein the reflection surface is formed in a curved surface shape that suppresses a spread angle after reflection of the incident light incident at a predetermined convergence angle or divergence angle by the condensing lens.   The reflection surface is set so that a minimum incident angle of a light beam reflected by the reflection surface and incident on the lower surface and / or the upper surface is equal to or greater than a total reflection angle at an interface between these surfaces and air. Item 4. The light collecting device according to any one of Items 1 to 3. The first condensing optical element and the second condensing optical element have a first side surface and a second side surface that connect the upper surface and the lower surface and face each other across the emission surface,
The light incident from the upper surface and reflected by the reflecting surface is totally reflected by the upper surface, the lower surface, the first side surface, and the second side surface and guided to the emitting surface. The condensing device as described in any one of -4.   The first condensing optical element and the second condensing optical element, which are arranged so as to be stacked one above the other, are arranged in close contact with each other, and the adhering upper and lower surfaces are integrally coupled by matching. The condensing device according to any one of claims 1 to 5. The first condenser lens and the second condenser lens are each composed of a plurality of unit condenser lenses that collect light.
The first condensing optical element and the second condensing optical element have a plurality of reflecting surfaces provided corresponding to incident light incident after being condensed by the unit condensing lenses. The light collecting device according to any one of claims 1 to 6, which is integrally formed. A plurality of the first side surfaces are provided corresponding to the individual reflection surfaces,
The light collecting device according to claim 7, wherein the second side surface is provided integrally with the plurality of reflection surfaces. The first condensing optical element and the second condensing optical element are:
The condensing device according to claim 8, wherein the first side surface and the second side surface are formed to be axially symmetric with respect to an axis extending in an emission direction. Each of the first condenser lens and the second condenser lens has a plurality of unit condenser lenses arranged in a matrix to form a lens array,
The first condensing optical element and the second condensing optical element include an element unit in which the reflecting surface, the first side surface, and the second side surface are formed corresponding to the unit condensing lens in each row. The light collecting device according to any one of claims 7 to 9, which is provided in a plurality of rows and formed integrally.   11. The plate or sheet according to any one of claims 1 to 10, wherein a size in a direction connecting the reflecting surface and the output surface is sufficiently larger than a size in a thickness direction connecting the upper surface and the lower surface. The light collecting device according to one item. The light collecting device according to any one of claims 1 to 11,
A photovoltaic device comprising: a photoelectric conversion element that photoelectrically converts light guided to the emission surface by the light collecting device. The light collecting device according to any one of claims 1 to 11,
A photothermal conversion device comprising: a photothermal conversion element for photothermal conversion of light guided to the emission surface by the condensing device.

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