JP2009258371A - Light introducing device, light converging unit, and light converging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a light introducing device which efficiently introduces solar light incident from an optional direction at a large angle of incidence, a light converging unit which converges the introduced light, and a light converging device equipped with the same. <P>SOLUTION: Two flat plate prisms 11 and 12 are disposed such that the angle that they form on the whole is an open (inclined) in the opening direction of a wedge angle α of the prisms. For example, the rear-side flat plate prism 12 is inclined to the front-side flat plate prism 11 by the wedge angle α of the flat plate prisms 11 and 12, and operating surfaces ES of the front-side flat plate prism 11 are parallel to a flat plate surface FS of the rear-stage flat plate prism 12. Consequently, light which is incident on a flat plate surface FS of a unit prism P1 of the front-side flat plate prism at an angle ϕ1 is refracted by an angle ϕ2 of refraction and projected from an operating surface ES at an angle ϕ3 of projection. This light is incident on a flat plate surface FS of a unit prism P2 of the rear-stage flat plate prism 12 at an angle ϕ3 of incidence. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light introducing device, a light collecting unit, and a light collecting device that introduce and collect light incident within a predetermined angle range.

  When using sunlight as an energy source, the utility value generally increases when the concentration factor is increased.

  Although it is necessary to use a lens or curved mirror to increase the focusing magnification, the position of the sun changes, so the entire device is rotated so that the lens or curved mirror is always at the position facing the sun, or the lens It is necessary to control the optical path using a prism or plane mirror so that sunlight always enters the curved mirror at the same angle.

  Among these methods, the method of controlling the optical path using a prism can be installed using the space between the roof and the attic, and even if it is installed over the entire area, it is not affected by other devices, and it can be viewed from all incident directions. It can be said that this method is suitable for use in ordinary households.

A normal prism becomes heavier as it gets larger, and the material cost increases, so a flat prism is preferable.
As a device using a flat prism, Patent Document 1 discloses a sunlight lighting device in which a daylighting prism is disposed at a predetermined angle with respect to a horizontal plane. Since the daylighting prism is disposed at a predetermined angle with respect to the horizontal plane, sunlight can be guided into the room relatively efficiently even when the elevation angle of the sun is small (altitude is low).

  However, since the solar light collecting device of Patent Document 1 uses only one daylighting prism, the refraction angle of light is small, and the sunlight cannot be guided in a certain direction, so that the sunlight is placed at a predetermined position. There was a problem that could not be condensed.

  Patent Document 2 discloses a solar tracking device in which two flat prisms are stacked in parallel to each other and at least one flat prism is rotated in a plane. This solar tracking device can guide sunlight in a certain direction.

FIG. 1 is a diagram showing the configuration of the solar tracking device disclosed in Patent Document 2. In this solar tracking device, flat prisms 1 and 2 are arranged in parallel as shown in FIG.
Japanese Patent Application Laid-Open No. 11-167084 JP-A-61-180217

  However, since the solar tracking device described in Patent Document 2 has two prisms stacked in parallel with each other, the light emitted from the first flat prism enters the second flat prism at a large angle. Resulting in. FIG. 1B is a diagram showing the state by taking out a unit prism of a flat plate prism. The light incident on the first prism P1 at the incident angle φ1 is refracted at the refraction angle φ2 and is emitted from the working surface (exiting surface) at the emitting angle φ3, but the flat plate surface (incident surface) of the second prism P2 Is tilted by the apex angle (hereinafter referred to as “wedge angle”) α of the prism in the direction opposite to the tilting direction of the working surface with respect to the working surface (outgoing surface) of the first prism P1. For this reason, the incident angle to the flat plate surface (incident surface) of the second prism P2 is larger than the outgoing angle φ3 from the exit surface of the first prism P1 to (φ3 + α).

  Therefore, the refraction effect by the second flat prism is reduced, and there is a problem that sunlight with a low elevation angle cannot be guided in an arbitrary direction by the flat prism.

  That is, as described in Patent Document 2, even if the wedge angle α is set to 30 °, the light that can be sent out vertically downward of the lower flat prism has an incident angle to the upper flat prism of 45.1 °. Limited to light up to.

  By increasing the wedge angle α and changing the refractive index of the material, all the light can be guided in a certain direction. However, even if the wedge angle α is increased further, The ratio of the light that impinges on the non-acting surface of the prism and cannot travel in the desired direction increases, and the loss increases. Further, since the refractive index of the transparent resin body used as the material for the flat prism is only about 1.5 to 1.6, the refractive index of the prism cannot be significantly increased.

  Accordingly, an object of the present invention is to provide a light introducing device that can efficiently introduce sunlight incident at a large incident angle from an arbitrary direction, a condensing unit that condenses the introduced light, and a collecting device including the same. It is to provide an optical device.

In order to solve the above problems, the present invention is configured as follows.
(1) In a light introducing device provided with a plurality of flat plate prisms,
Among the plurality of flat plate prisms, at least two flat plate prisms on the front side and the back side have a prism surface of at least one flat plate prism facing the other flat plate prism, and the wedge angle of the one flat plate prism is increased. The other flat prism is disposed so as to be relatively open in the angular direction, and the two flat prisms are rotatably provided.

  With this configuration, it is possible to guide sunlight incident at a large incident angle in a certain direction without increasing the wedge angle of the prism. Therefore, sunlight incident from a low elevation angle can also be introduced in a predetermined direction.

(2) The two flat prisms have, for example, a common first rotation axis, and one of the two flat prisms has a second rotation axis independent of the first rotation axis. Shall.

  Thereby, by rotating with an original rotation axis, an equivalent wedge angle by a plurality of flat prisms changes, and sunlight incident from a wide range (a large solid angle range) can be guided in a certain direction. .

(3) Regardless of the rotation of the two flat prisms, the surfaces of the two flat prisms facing each other shall maintain a substantially parallel relationship.
As a result, light is incident on the rear plate prism at an angle substantially equal to the emission angle of the light emitted from the front plate prism. Therefore, light with a larger incident angle can be introduced in a predetermined direction.

(4) Of the two flat prisms, at least one flat prism is rotated about an axis perpendicular to the incident surface as a rotation axis.

  Thereby, the incident angle of light can be kept constant, and the design becomes easy. In addition, control during tracking becomes easy.

(5) When the two flat prisms are arranged so that their opposing surfaces are arranged in parallel, a wedge angle necessary for the two flat prisms is represented by α, and when the wedge angles of the two flat prisms are represented by β, β <α. More than the case where the opposing surfaces are arranged in parallel, the prism surface is arranged so that the other plate prism opens in the opening angle direction of the wedge angle of one plate prism facing the other plate prism. It shall be assumed.

  Thereby, it can be made to inject into a back | latter stage flat prism at an angle smaller than the angle radiate | emitted from a front | former stage flat prism, or an equivalent angle. Further, since the wedge angle becomes small, the proportion of light incident on the non-working surface becomes small, and the overall loss can be reduced.

(6) When the surface of one flat prism facing the other flat prism is a flat surface, the flat surface of the two flat prisms is the surface of the one flat prism facing the other flat prism. In the case of a prism surface, a surface that is opened at a predetermined angle from the prism surface in the opening angle direction of the wedge angle β of the one flat prism has a parallel relationship regardless of the rotation of the two flat prisms. Shall be maintained.

  With this configuration, the plane maintaining the parallel relationship can be considered by replacing it with the exit / incident surface of each flat prism, which facilitates the design and facilitates control during tracking.

(7) The incident surface of at least one of the front plate prism and the rear plate prism is a flat surface.

  Thereby, since light does not enter the non-working surface of the prism surface, the loss can be suppressed accordingly.

(8) A condensing unit is configured by including the light introducing device having any one of the above-described configurations and a condensing lens that condenses light emitted from the last stage among the plurality of flat plate prisms.

  With this configuration, the collected light can be easily transported through, for example, an optical duct or an optical fiber, and can be used as energy at the transport destination.

(9) The flat prism arranged at the last stage among the plurality of flat prisms has a flat exit surface, and the condenser lens is formed on the exit surface of the flat prism.

  With this configuration, a lens such as a Fresnel lens or a half-convex lens can be easily formed in close contact with the exit surface of the flat prism arranged at the last stage. By forming these lenses, the light emitted from the flat prism can be collected at one point. Therefore, the lens can be formed with a simpler structure than when a lens is separately provided, and the loss is small.

(10) A condensing device is configured by arranging a plurality of the condensing units such that the incident surfaces of the first-stage flat prisms are substantially the same plane among the plurality of flat prisms.

  As a result, each light collecting unit is provided with a large-area incident surface without blocking incident light to other light collecting units, and a highly efficient light collecting device can be configured as a whole.

  According to the present invention, sunlight incident at a large incident angle can be guided in a certain direction without increasing the prism wedge angle, and sunlight incident from a low elevation angle can also be introduced in a predetermined direction. Tracking control is also easy. Furthermore, the overall loss can be reduced.

<< First Embodiment >>
The light introducing device according to the first embodiment will be described with reference to FIGS.
FIG. 2 is a diagram illustrating a configuration of a main part of the light introducing device according to the first embodiment. 2A shows the arrangement relationship between the two flat prisms 11 and 12, and FIG. 2B shows the arrangement relationship between the unit prisms.

  In FIG. 2 (A), sunlight is incident from above in the figure and introduced downward. Both the front-stage flat prism 11 and the rear-stage flat prism 12 have a flat surface FS on the upper surface and a prism surface PS on the lower surface. The two flat prisms 11 and 12 are arranged so that the angle formed by the two is relatively open (inclined) in the opening angle direction of the wedge angle α of the prism. In this example, the rear-stage flat prism 12 is opened with respect to the front-stage flat prism 11 by the wedge angle α in the opening angle direction of the wedge angle α of the front-stage flat prism 11. That is, the flat plate surface FS of the front-stage flat prism 11 and the flat plate surface FS of the rear-stage flat prism 12 are inclined. Therefore, as shown in FIGS. 2A and 2B, the working surface ES of the front-side flat prism 11 and the flat surface FS of the rear-side flat prism 12 which are opposing surfaces are in a parallel relationship.

  Therefore, as shown in FIG. 2B, the light incident at the incident angle φ1 on the flat plate surface FS of the unit prism P1 of the front-side flat prism is refracted at the refraction angle φ2 and is emitted from the working surface ES at the output angle φ3. Exit. This light enters the flat plate surface FS of the unit prism P2 of the rear flat plate prism 12 at an incident angle φ3.

  As is clear from the comparison with the example shown in FIG. 1B, the refraction effect by the flat prism 12 on the rear stage side is not reduced, and the incident light with a large incident angle φ1 (low elevation angle) is also in a predetermined direction. Can be introduced. Therefore, it becomes possible to adapt over a wider angle range.

  Further, if the flat prism 12 shown in FIG. 2 is rotated by the rotation axis indicated by the alternate long and short dash line perpendicular to the flat surface FS in FIG. 2A, the angle of deflection by the two flat prisms 11 and 12 is wide. It can be arbitrarily changed over (solid angle). This is shown in FIG.

FIG. 3A shows a case where the wedge angle is maximized (= 2α) when the unit prisms P1 and P2 of two flat prisms are overlapped.
FIG. 3B shows a case where the wedge angle obtained by combining the two prisms P1 and P2 is equivalently zero.
FIG. 3C is an intermediate state between FIG. 3A and FIG. 3B, and an equivalent wedge angle by combining the prisms P1 and P2 can be in the range of 0 to 2α.

  In this example, as shown in FIG. 2B, the lower surface of the front plate prism 11 and the upper surface of the rear plate prism 12 are parallel. The air layer is equivalently negligible, and can be handled as a superposition of the upper and lower unit prisms, as shown on the right side of each figure in FIG.

A specific design example of the flat prisms 11 and 12 is as follows.
Refractive index: 1.5 (acrylic resin)
Shape: Disc shape with a diameter of 300mm (Thickness: 2mm)
Wedge angle α = 21 ° Unit prism pitch: 1 mm
Unit prism height difference: 0.36 mm
The angle γ formed between the non-working surface NS and the flat plate surface FS on the prism surface is set to 80 °, which is smaller than 90 °, in order to improve the mold separation during molding.

  Although the wedge angle α is only 21 ° under this condition, the rear-side flat prism is shown in FIG. 2B in which the incident angle φ1 is in the range of 0 to 90 °, that is, incident light from all directions. The twelve working surfaces ES can be derived in the vertical axis direction.

  In addition, the loss resulting from the reflection accompanying the difference in refractive index at the interface between the flat prisms 11 and 12 and the non-working surface NS that does not contribute to refraction effectively occurs.

  FIG. 4 is a cross-sectional view of the light introducing device 101 having a mechanism for rotating the two flat prisms 11 and 12. The front-stage flat prism 11 is attached to the rotary frame 21. Further, the rear plate prism 12 is attached to the rotary frame 22. The rotating frame 21 is engaged with a gear 31, and the gear 31 is rotated by a motor 41. Similarly, the rotating frame body 22 meshes with the gear 32, and the gear 32 is rotated by the motor 42.

  The flat prisms 11 and 12 rotate around the central axis perpendicular to the flat plate surface of the front-side flat prism 11 by the rotation of the motor 41. Further, the post-stage side plate prism 12 rotates around the central axis perpendicular to the flat plate surface by the rotation of the motor 42. The two rotation axes indicated by the one-dot chain line form an angle equal to the wedge angle α.

  Thus, an equivalent wedge angle is controlled by the relative angle between the two flat prisms 11 and 12, and the deflection direction (azimuth) of incident light is controlled by the overall angle of the two flat prisms 11 and 12.

  According to the first embodiment, the rotation axis of the rear plate prism 12 can be made thin because the rotation axis of the rear plate prism 12 coincides with the vertical axis of the flat plate surface. Therefore, the entire apparatus can be thinned. In addition, since both of the rotation axes are vertical axes of the flat plate surface, the prism can be easily attached and adjusted at the time of manufacturing the rotation mechanism portion, and it can be easily confirmed whether or not it is operating normally.

  In addition, when the flat prisms 11 and 12 are considered as normal thick prisms, the facing surfaces of both prisms are always kept in parallel so that the direction of rotation of both prisms can be adjusted to a desired optical path. Easy to calculate.

  The two flat prisms 11 and 12 are rotated together with the vertical axis of the flat plate surface that is the incident surface of the rear flat plate prism 12 as the rotation axis, and the front flat plate prism 11 is rotated along the vertical axis of the prism surface that is the output surface thereof. It is good also as a structure which rotates independently as a rotating shaft. That is, the master-slave relationship may be reversed from that shown in FIG.

  FIG. 5 shows the structure on the incident surface side in more detail while using the light introducing device 101 shown in FIG. In FIG. 5, a glass (tempered glass) plate 52 is disposed in parallel to the flat plate surface of the front plate prism 11 of the light introducing device 101, and between the glass plate 52 and the flat plate surface of the front plate prism 11. A matching layer 51 is provided. The matching layer 51 is, for example, an oily refractive index matching liquid having a refractive index approximate to or intermediate between the refractive indexes of the glass plate 52 and the flat prism 11.

  With such a configuration, since the matching layer 51 is always filled in the interface between the flat plate surface of the front-side flat prism 11 and the glass plate 52 and no air layer enters, the light can be increased without increasing the number of interfaces with respect to the optical path. The introduction apparatus 101 can be protected.

  Next, as shown in FIGS. 2 to 5, a difference in loss is shown between the case where the flat plate surface of the flat plate prism is used as the incident surface and the case where the prism surface of the flat plate prism is used as the incident surface.

  FIG. 6 shows the incident angle when the incident surface side is a prism surface. FIG. 8 shows the incident angle when the incident surface side is a flat surface. Here, light incident from the direction indicated by the broken line is used in a state where the flat prism 14 is rotated and incident from the direction indicated by the solid arrow in the figure. When the direction indicated by the solid arrow from the incident surface is a positive direction, the incident angle is always a positive value.

  FIG. 7 is a diagram showing the relationship of the transmittance to the incident angle when the incident surface side is a prism surface, and FIG. 9 is the relationship of the transmittance to the incident angle when the incident surface side is a flat surface. It is a figure shown about. 7 and 9 show the light transmittance when the wedge angle α = 20 ° and the angle γ between the non-working surface and the flat plate surface is 80 °. 7 and 9, (A) shows the ratio of passing through the working surface, and (B) shows the case of taking a weighted average considering the interface reflection and taking into consideration the light intensity depending on the incident angle. In FIG. 7A and FIG. 9A, the region where the incident angle is negative is an angle range that is unnecessary (not incident) for tracking sunlight.

  As shown in FIGS. 6 and 7, when the incident surface is a prism surface, the light incident on the non-working surface of the prism surface increases as the incident angle increases and the light transmittance decreases. As shown in FIG. 7, when the incident surface is a prism surface, the average transmittance is 75.6% even if the incident surface is rotated by a rotation axis perpendicular to the working surface.

  By the way, when the incident surface is a prism surface, if the flat prism is installed so that the center direction of the incident range of light coincides with the vertical axis direction of the working surface, the incident light is transmitted through the flat prism over a wide angle range. be able to. However, for example, when considering a case where a condensing device is configured by arranging a plurality of condensing units in which the incident surface of the front-side flat prism is a prism surface, the shadow of the adjacent condensing unit is created. The average transmittance is further reduced to 63.2%.

  On the other hand, when the incident surface is a flat plate surface as shown in FIGS. 8 and 9, incident light from a wide angle range is once transmitted through the flat plate prism. Although incident light having a large incident angle has a component that passes through the non-working surface, a relatively large proportion of light passes through the working surface. Therefore, the average transmittance when the incident surface is a flat surface is 80.9%.

  In this case, since the incident surface is a flat plate surface even if a plurality of light collecting units are arranged close to each other, the incident surface of the front-side flat prism of each light collecting unit can be arranged in a planar shape. Therefore, there is no shadow of adjacent light collecting units, and there is little decrease in average transmittance.

<< Second Embodiment >>
The light introducing device according to the second embodiment will be described with reference to FIGS.
FIG. 10 is a cross-sectional view showing the configuration of the main part of the light introducing device according to the second embodiment. In the first embodiment, the rear surface side plate prism 12 is arranged so that the incident surface thereof is on the flat surface surface side. However, in the second embodiment, the prism surface PS of the rear surface side plate prism 13 is incident as shown in FIG. It arranges so that it may become a field.

  In this example, the opposing flat prisms are relatively opened in the opening angle direction of the wedge angles of the flat prisms 11 and 13. That is, the flat plate surface FS of the front-stage flat prism 11 and the flat plate surface FS of the rear-stage flat prism 13 are inclined. Therefore, the working surface of the front-stage flat prism 11 and the working surface of the rear-stage flat prism, which are opposite surfaces, can be in a parallel relationship.

  FIG. 10B shows a structure for rotating the front-side flat prism 11 and the rear-side flat prism 13. As shown in this figure, the front-side flat prism 11 is attached to the rotary frame 21. The rear stage side plate prism 13 is attached to the rotating frame body 23. The rotating frame 21 is engaged with a gear 31, and the gear 31 is rotated by a motor 41. Similarly, the rotating frame body 23 meshes with the gear 33, and the gear 33 is rotated by the motor 43.

  The plate prisms 11 and 13 are rotated about the central axis perpendicular to the plate surface of the front plate prism by the rotation of the motor 41. Further, the latter-stage flat prism 13 is rotated by the rotation of the motor 43 with the central axis perpendicular to the working surface of the prism surface as the rotation axis. The two rotation axes indicated by the one-dot chain line form an angle equal to the wedge angle α.

  Thus, an equivalent wedge angle is controlled by the relative angle between the two flat prisms 11 and 13, and the deflection direction (azimuth) of incident light is controlled by the overall angle of the two flat prisms 11 and 13.

  The two flat prisms 11 and 13 are rotated together with an axis perpendicular to the working surface of the prism surface that is the incident surface of the rear-side flat prism 13 as a rotation axis, and the front-side flat prism 11 is a prism that is the output surface. It is good also as a structure rotated independently by making the vertical axis | shaft of a surface into a rotating shaft. That is, the master-slave relationship may be reversed from that shown in FIG.

FIG. 11 is a cross-sectional view illustrating a configuration of a light collecting unit 201 that includes the light introducing device 102 illustrated in FIG. 10 and further includes a light collecting unit.
In FIG. 11, a Fresnel lens 19 is provided on the lower surface (flat surface side) of the rear-stage flat prism 13. The light receiving portion of the optical fiber OF is disposed at the focal point FP of the Fresnel lens 19. Since the light is emitted in a direction perpendicular to the flat plate surface of the latter-stage flat plate prism 13, these lights are collected at the focal point FP by the Fresnel lens 19.

  In order to reduce the number of interfaces, a matching layer is provided between the flat plate surface of the rear-stage flat prism 13 and the flat plate surface of the Fresnel lens 19, or the both layers are formed integrally and no air layer is interposed.

  The light collected at the focal point FP in this way is transmitted as light energy to a predetermined location through the optical fiber OF.

<< Third Embodiment >>
FIG. 12A is a cross-sectional view of the main part of the light introducing device 103 according to the third embodiment. FIG. 12B shows a structure for rotating the front-side flat prism 14 and the rear-side flat prism 13.

The third embodiment is an example in which the incident surface side is a prism surface for both the front-side flat prism 14 and the rear-side flat prism 13.
As shown in FIG. 12B, the front-stage flat prism 14 is attached to the rotary frame 24. The rear stage side plate prism 13 is attached to the rotating frame body 23. The rotating frame body 24 meshes with a gear 34, and the gear 34 is rotated by a motor 44. Similarly, the rotating frame body 23 meshes with the gear 33, and the gear 33 is rotated by the motor 43.

  With this configuration, the front-side flat prism 14 rotates about an axis perpendicular to the flat surface that is the exit surface thereof, and the rear-stage flat prism 13 has an axis that is perpendicular to the working surface ES of the prism surface. It rotates as a rotation axis.

  As in the first and second embodiments, the front side plate prism 14 and the rear side plate prism 13 are rotated about an axis perpendicular to the working surface ES of the prism surface that is the incident surface of the front side plate prism 14. The rear plate prism 13 may be rotated about an axis perpendicular to the working surface ES of the prism surface that is the incident surface of the rear plate prism 13.

  Thus, an equivalent wedge angle is controlled by the relative angle between the two flat prisms 14 and 13, and the deflection direction (azimuth) of incident light is controlled by the overall angle of the two flat prisms 14 and 13.

<< Fourth Embodiment >>
FIG. 13 is a cross-sectional view showing the configuration of the main part of the light introducing device 104 according to the fourth embodiment. In this example, a front-stage flat prism 15 and a rear-stage flat prism 16 each having a wedge angle β1 are used. The front-side flat prism 15 has an exit surface as a prism surface, the rear-stage flat prism 16 has an incident surface as a prism surface, and the two flat prisms 15 and 16 are arranged in the inclination direction of the wedge angle β1 of the opposing flat prisms 15 and 16. The angle is 2 × (β1 + β2).

  In other words, the wedge angle required when the working surfaces of the two prisms are arranged in parallel is represented by α, where β1 <α, and the working surfaces of the two flat prisms are arranged in parallel. Therefore, the opposing prism is further opened by an angle 2 × β2 in the opening angle direction of the wedge angle β1 of the flat plate prism.

  Each of the flat prisms 15 and 16 is regarded as a combined prism of a prism having a wedge angle β1 and an air prism having a wedge angle β2, and the working surfaces of the air prisms are opposed to each other in parallel. That is, the planes of the flat prisms 15 and 16 that are open at an angle β2 are parallel to the opening angle direction of the wedge angle β1 of the flat prisms 15 and 16 from the prism surfaces of the flat prisms 15 and 16, respectively. Then, both rotate with the vertical axis of the flat plate surface of the front-stage flat prism as the rotation axis, and the rear-stage flat prism 16 is a surface facing the air prisms (that is, from the working surface of the flat prism 16 to the flat prism). 16 is a structure that rotates about an axis perpendicular to the opening angle direction 16 by an angle β2).

  FIG. 13B shows a structure for rotating the front-side flat prism 15 and the rear-side flat prism 16. As shown in this figure, the front-side flat prism 15 is attached to the rotary frame 25. The rear stage side plate prism 16 is attached to the rotating frame 26. The rotating frame 25 is engaged with a gear 35, and the gear 35 is rotated by a motor 45. Similarly, the rotating frame 26 is engaged with a gear 36, and the gear 36 is rotated by a motor 46.

  The plate prisms 15 and 16 are rotated by the rotation of the motor 45, and the rear stage side plate prism 16 is also rotated by the rotation of the motor 46. The two rotation axes indicated by the one-dot chain line form an angle equal to the wedge angle (β1 + β2) of the composite prism.

  Thus, the equivalent wedge angle is controlled by the relative angle between the two flat prisms 15 and 16, and the deflection direction (azimuth) of the incident light is controlled by the overall angle of the two flat prisms 15 and 16.

  When the two flat prisms shown in the first to third embodiments are used so that the working surfaces facing each other are parallel to each other, all incident angles of light are perpendicular to the exit surface of the rear flat plate prism. In order to derive in the direction, as described above, the wedge angle of the prism was 21 °. However, in the fourth embodiment, since the incident surface of the flat plate prism on the rear stage is arranged so as to be inclined in the inclination direction of the output surface, the wedge angle β1 of the two prisms 15 and 16 is 20.4 °. For example, it is possible to send out incident light from all directions (that is, in a range where the incident angle with respect to the front-side flat prism is 0 to 90 °) in the vertical axis direction of the exit surface of the rear-side flat prism. However, since the angle β1 + β2 = 21.4 ° occupied by the composite prism with the air prism, the rotation mechanism portion of the rear side plate prism is slightly thicker than the example shown in FIG.

  If the wedge angle of the flat prism is thus reduced, the transmission loss due to the flat prism is reduced.

  In the case where light of the same incident angle is transmitted and the area of the flat prism is the same, if β2 increases, the loss due to the fact that the front-side flat prism 15 passes but the rear-stage flat prism 16 does not pass is lost. However, as the wedge angle β1 of the flat prism becomes smaller as described above, the rate at which light strikes the non-working surface of the prism surface and does not travel in the desired direction decreases. Up to a certain value of β2, since the latter loss decrease is superior to the former loss increase, the overall efficiency is improved. For this reason, the light introducing device 104 shown in the fourth embodiment is expected to be slightly improved compared to the light introducing device 102 shown in the second embodiment.

  Note that, as shown in FIG. 2 as the first embodiment, the two flat prisms 11 and 12 can be applied to both of which the prism surfaces are on the exit surface side. In this case, the flat prism 12 opens at an angle β2 in the opening angle direction of the wedge angle β1 of the flat prism 11 as compared with the case where the two opposing surfaces are arranged in parallel. Then, the plane of the flat prism 11 is rotated so that the plane of the flat prism prism 12 is parallel to the plane of the flat prism 11 that is opened by the angle β2 in the opening angle direction of the wedge angle β1 of the flat prism 11. According to this, overall efficiency is expected to be improved by about 1% in the range of β1 = 18 to 15 ° and β2 = 5 to 10 °. The reason is that, as in the second embodiment, when the prism surfaces are opposed to each other and the two flat prisms 11 and 13 form a large angle, if the angle is further increased, the front-side flat prism is Although the loss due to passing through the latter but not passing through the latter-stage flat prism is greatly increased, as in the first embodiment, if only one of the two opposing flat prisms is a prism surface, This is because the angle formed by the flat prism is not originally large, and even if the angle is widened, the increase in loss is small.

<< Fifth Embodiment >>
FIG. 14 is a cross-sectional view illustrating a configuration of a light collecting apparatus 301 according to the fifth embodiment. This condensing device 301 is provided on an inclined roof facing the south side of the house. A glass plate 52 is provided on the incident surface of the roof, and light condensing units 201A to 201D similar to those shown in FIG. However, in this figure, four condensing units 201A to 201D appear in the cross section, but they are also arranged in the direction perpendicular to the paper surface (depth direction).

  In this way, by arranging a plurality of the incident surfaces of the first (previous) plate prisms among the plurality of plate prisms of the plurality of light collecting units so as to form substantially the same plane, other adjacent light collecting units are arranged. Therefore, a highly efficient condensing device can be constructed as a whole without blocking incident light.

  As shown in FIG. 4, when the exit surface of the latter-stage flat prism 12 is a prism surface, a Fresnel lens is disposed on the flat plate surface side (incident surface side), or both are integrally molded. Also good. Further, a composite pattern of a prism pattern of a flat plate prism and a Fresnel lens pattern may be provided on the same surface to integrate them.

  In each of the embodiments described above, two flat prisms are provided. However, when three or more flat prisms are provided, the present invention may be similarly applied to two opposing flat prisms.

  Moreover, in each embodiment shown above, it has arrange | positioned so that the surface which a flat prism opposes, or the surface which an air prism opposes may become substantially parallel, However, It is not restricted to this, The flat plate surface of two flat prisms is It is only necessary that the two flat prisms be inclined so that they are not parallel but are relatively opened in the opening angle direction of the wedge angle.

It is a figure which shows the structure of the solar tracking apparatus shown by patent document 2. FIG. It is a figure which shows the structure of the principal part of the light introduction apparatus which concerns on 1st Embodiment. It is a figure which shows the example of control of the deflection angle of the light introduction apparatus which concerns on 1st Embodiment. It is sectional drawing of the light introduction apparatus 101 provided with the mechanism in which the two flat prisms 11 and 12 are rotated independently. FIG. 5 is a diagram more specifically showing the structure on the incident surface side while using the light introducing device 101 shown in FIG. 4. It is a figure shown about the incident angle when the incident surface side is made into a prism surface. It is a figure which shows the relationship of the transmittance | permeability with respect to an incident angle when an incident surface side is made into a prism surface. The incident angle when the incident surface side is a flat surface is shown. It is a figure which shows the relationship of the transmittance | permeability with respect to an incident angle when an incident surface side is made into a flat plate surface. It is sectional drawing which shows the structure of the principal part of the light introduction apparatus which concerns on 2nd Embodiment. It is sectional drawing of the condensing unit 201 provided with the light introduction apparatus 102 shown in FIG. 10, and also provided with the condensing means. It is sectional drawing which shows the structure of the principal part of the light introduction apparatus 103 which concerns on 3rd Embodiment. It is sectional drawing which shows the structure of the principal part of the light introduction apparatus 104 which concerns on 4th Embodiment. It is sectional drawing which shows the structure of the condensing apparatus 301 which concerns on 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Preliminary side plate prism 12 ... Rear stage side plate prism 13 ... Rear stage side plate prism 14 ... Prestage side plate prism 15 ... Prestage side plate prism 16 ... Rear stage side plate prism 19 ... Fresnel lenses 21-26 ... Rotating frame bodies 31-36 ... Gear 41-46 ... Motor 51 ... Alignment layer 52 ... Glass plate 101-104 ... Light introducing device 201 ... Condensing unit 301 ... Condensing device ES ... Working surface FP ... Focus FS ... Plate surface NS ... Non-working surface OF ... Optical fibers P1, P2 ... Unit prism PS ... Prism surface

Claims (10)

In the light introducing device provided with a plurality of flat plate prisms,
Among the plurality of flat plate prisms, at least two flat plate prisms on the front side and the back side have a prism surface of at least one flat plate prism facing the other flat plate prism, and the wedge angle of the one flat plate prism is increased. A light introducing device characterized in that the other flat prism is disposed so as to be relatively open in the angular direction, and the two flat prisms are rotatably provided.   The two flat prisms have a first rotation axis that is common to both, and one of the two flat prisms has a second rotation axis that is independent of the first rotation axis. The light introducing device described in 1.   3. The light introducing device according to claim 1, wherein the surfaces of the two flat prisms facing each other maintain a substantially parallel relationship regardless of the rotation of the two flat prisms.   4. The light introducing device according to claim 3, wherein at least one of the two flat prisms rotates about an axis perpendicular to an incident surface as a rotation axis. 5.   When the two flat prisms are arranged so that their opposing surfaces are parallel, the necessary wedge angle is expressed as α, and when the wedge angles of the two flat prisms are expressed as β, β <α. And, when the opposing surfaces are arranged in parallel, the prism surface is arranged in a relationship in which the other flat prism opens in the opening angle direction of the wedge angle of one flat prism facing the other flat prism, The light introducing device according to claim 1 or 2.   In the two flat prisms, when the surface of one flat prism facing the other flat prism is a flat plate surface, the flat plate surface is the plane of the one flat prism facing the other flat prism. In some cases, a surface that is opened from the prism surface by a predetermined angle in the opening angle direction of the wedge angle β of the one flat prism maintains a parallel relationship regardless of the rotation of the two flat prisms. The light introducing device according to claim 5.   The light introducing device according to claim 1, wherein an incident surface of at least one of the front-stage flat prism and the rear-stage flat prism is a flat surface.   A condensing unit comprising the light introducing device according to claim 1 and a condensing lens that condenses light emitted from the last stage among the plurality of flat prisms.   The condensing unit according to claim 8, wherein the flat prism arranged at the last stage among the plurality of flat prisms has a flat exit surface, and the condenser lens is formed on the exit surface of the flat prism. .   10. A condensing device in which a plurality of condensing units according to claim 8 or 9 are arranged such that incident surfaces of first-stage flat prisms are substantially coplanar among the plurality of flat prisms.

Images