JP2015005453A - Solar lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar lighting system which can effectively suppress the fluctuation in lighting efficiency depending on season or time zone.SOLUTION: A solar lighting system 1 comprises lighting means 10 having a concave lens part 13 for lighting.

Description

  The present invention relates to a solar light daylighting system for daylighting, and relates to a solar daylighting system capable of effectively suppressing fluctuations in daylighting efficiency depending on seasons and time zones.

For example, as disclosed in Patent Documents 1 and 2, the development of a sunlight lighting system that collects sunlight and guides the light to a predetermined region is underway. The solar lighting system is used for indoor lighting, for example, as a system having a lighting means installed on a roof and a light guide means for guiding the sunlight collected by the lighting means into the room. Such a solar lighting system is attracting attention as a system that contributes to CO ₂ reduction and can directly realize energy saving.

JP2012-189280 JP2013-11670A

  By the way, the position of the sun changes according to a time zone and a season. That is, the incident direction of sunlight when entering the sunlight lighting system changes according to the time zone and season. Although patent document 1 and patent document 2 make the improvement of the lighting efficiency a subject, the change of the incident direction of sunlight is not dealt with at all. It is also considered that the lighting efficiency can be stabilized without depending on the time zone and the season by making the position or orientation of the daylighting means of the sunlight daylighting system movable according to the position of the sun. However, if the daylighting unit of the sunlight daylighting system is movable, the daylighting unit becomes complicated and the manufacturing cost and the maintenance cost of the daylighting unit increase. Further, in a solar lighting system that uses sunlight as indoor lighting, the necessity of power to move the lighting means itself is not compatible from the viewpoint of energy saving.

  The present invention has been made in consideration of the above points, and an object of the present invention is to provide a solar lighting system that can effectively suppress fluctuations in lighting efficiency due to seasons or time zones.

  The sunlight daylighting system according to the present invention includes daylighting means having a concave lens portion for daylighting.

  In the solar light daylighting system according to the present invention, the solar light daylighting system further includes light guide means connected to the daylighting means and receiving light from the daylighting means, and the light guide means is at least at an end portion on the side connected to the daylighting means An optical path parallel to the predetermined first direction may be defined.

  In the daylighting system according to the present invention, the daylighting means includes a traveling direction of light incident on one position of the concave lens portion at one time and a light incident on another position of the concave lens portion at another time. The traveling direction may be changed to be the first direction.

In the sunlight daylighting system according to the present invention, the daylighting unit further includes a prism array including a plurality of unit prisms between the concave lens portion and the light guide path,
The concave lens portion has a second direction as a traveling direction of light incident on one position of the concave lens portion at one time and a traveling direction of light incident on another position of the concave lens portion at another time. Change to
The prism array may change a traveling direction of light traveling in the second direction from the concave lens portion to the first direction.

  In the daylighting system according to the present invention, the daylighting means includes an optical sheet, the concave lens portion is provided on a light incident side surface of the optical sheet, and the prism array is provided on a light output side surface of the optical sheet. It may be provided.

  In the sunlight lighting system according to the present invention, the concave lens portion may be a Fresnel lens.

According to the present invention, it is possible to effectively suppress fluctuations in daylighting efficiency due to seasons or time zones. Therefore, it is possible to contribute to energy saving and CO ₂ reduction by using the sunlight collected by the sunlight collecting system according to the present invention.

FIG. 1 is a longitudinal sectional view schematically showing a building to which a solar lighting system according to the first embodiment of the present invention is attached. FIG. 2 is a schematic diagram showing a main part of the sunlight lighting system shown in FIG. FIG. 3 is a cross-sectional view showing the daylighting means of the sunlight daylighting system shown in FIG. FIG. 4 is a diagram corresponding to FIG. 2, and is a schematic diagram illustrating an example in which the concave lens portion is a part of the lens. FIG. 5 is a schematic view showing a main part of a sunlight lighting system according to the second embodiment of the present invention. 6 is a cross-sectional view showing the daylighting means of the sunlight daylighting system shown in FIG. FIG. 7 is a cross-sectional view corresponding to FIG. 6 and showing a modification of the daylighting means shown in FIG. FIG. 8 is a cross-sectional view corresponding to FIG. 5 and showing another modification of the daylighting means. FIG. 9 is a view corresponding to FIG. 6 and an enlarged sectional view of the daylighting means shown in FIG. FIG. 10 is a diagram corresponding to FIG. 8 and is a diagram for explaining an embodiment of the sunlight lighting system. FIG. 11 is a diagram corresponding to FIG. 9 and is a diagram for explaining an embodiment of the sunlight lighting system.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIGS. 1 to 10 attached to the present specification, for convenience of illustration and understanding, the scale and the vertical / horizontal dimension ratio are appropriately changed and exaggerated from those of the actual ones.

<< First Embodiment >>
1 to 3 are diagrams for explaining a first embodiment of the present invention. Among these, FIG. 1 is a longitudinal sectional view schematically showing a building to which a solar lighting system is attached.

  As shown in FIG. 1, the sunlight lighting system 10 includes a daylighting means 10 having a concave lens 12 for daylighting, and a light guide means 30 connected to the daylighting means 10 and receiving light from the daylighting means 10. ing. In the example described below, the daylighting means 10 is attached to the roof 91 of the building 90, and light collected by the daylighting means 10 is guided to the room 95 in the building 90 via the light guide means 30. .

  First, the light guide means 30 will be described. As shown in FIG. 1, the light guide unit 30 defines an optical path parallel to the first direction d <b> 1 at least at the end connected to the daylighting unit 10. As a specific configuration, the light guide means 30 includes a light guide path 31 connected to the daylighting means 10 and extending linearly in the first direction d1, and a connection path 32 extending from the light guide path 31 to the ceiling 93. Yes. One end of the light guide 31 surrounds the daylighting means 10, and the other end of the light guide 31 is connected to the connection path 32. The connection path 32 extends along a curved or broken line path and is connected to the room 95.

  Such a light guide path 31 and the connection path 32 may be comprised with a hollow cylindrical member. The inner surface of the cylindrical member has a function of reflecting light, preferably, a function of specularly reflecting light, that is, a function of specularly reflecting light, whereby light passing through the interior is reflected and guided by the inner surface. As an example, such a cylindrical member can be a duct manufactured using a metal plate whose inner surface is coated with a highly reflective material such as silver.

  In the example shown in FIG. 1, a diffusion plate 96 is installed at the end of the connection path 32 connected to the room 95. According to the diffusing plate 96, the inside of the room 95 can be illuminated uniformly. However, the diffusion plate 96 may not be installed at the end of the connection path 32, and the light guided in the light guide means 30 may be emitted directly from the end of the connection path 32.

  Next, the daylighting means 10 will be described with reference to FIGS. FIG. 2 is a schematic view showing a main part of the sunlight lighting system 1, and FIG. 3 is a cross-sectional view showing the lighting means 10. As shown in FIGS. 2 and 3, the daylighting means 10 has a first optical sheet 11. The first optical sheet 11 includes a sheet-like main body portion 12 and a concave lens portion 13 disposed on the light output side surface 12 b of the main body portion 12.

  The light exit side surface of the first optical sheet 11 is formed by a concave lens portion 13. On the other hand, the light incident side surface of the first optical sheet 11 is formed by the light incident side surface 12a of the main body 12, and is formed as a smooth surface in the illustrated embodiment.

  In the present specification, “smoothing” means smoothing in an optical sense. That is, here, it means the degree to which a certain percentage of transmitted light in the visible light band is refracted while satisfying Snell's law. Therefore, for example, if the 10-point average roughness Rz (JISB0601) of the light incident side surface 12a of the main body 12 is equal to or shorter than the shortest visible light wavelength (0.38 μm), the surface is sufficiently smooth.

  The first optical sheet 11 of the present embodiment is installed so that the optical axis X of the concave lens portion 13 is parallel to the first direction d1 that is the longitudinal direction of the light guide path 31. Then, sunlight is incident as a parallel light beam on the entire light incident side of the first optical sheet 11, refracted by the concave lens portion 13, and proceeds toward the light guide means 30 as divergent light.

  By the way, it is also conceivable to form the daylighting means using a convex lens instead of a concave lens. In this case, the light from the sun is refracted by the convex lens and collected in one region in the light guide means. However, there is a possibility that a high heat load due to the energy of light is applied to the region where the light in the light guide unit is condensed, and the light guide unit in the vicinity of the region may be damaged. When the light guiding means is damaged, the light guiding function is remarkably lowered, and as a result, the light collecting efficiency is greatly reduced.

  On the other hand, in the present embodiment, the daylighting unit 10 employs the concave lens unit 13, and light from the sun is refracted by the concave lens unit 13 and travels into the light guide unit 30 as divergent light. Since light from the sun travels in the light guide means 30 as diverging light, it does not collect in one area in the light guide means 30. For this reason, it can prevent effectively that the light guide means 30 is damaged by the energy of light.

  The concave lens portion 13 does not have to be a complete lens shape having a clear focal point. The shape of the concave lens portion 13 and the optical shape obtained from the shape are within a range in which light from the sun can be emitted as diverging light. You may change a characteristic suitably.

  Now, the inclination of the surface of the concave lens portion 13 changes continuously in the plane, and a different optical action can be provided for incident light at each position of the concave lens portion 13. In the present embodiment, by appropriately setting the inclination of the surface of the concave lens portion 13, at least the concave lens portion 13 is different from the traveling direction of the light incident on one position of the concave lens portion 13 in one time, The traveling direction of light incident on another position of the concave lens portion 13 with time is changed so as to be the first direction d1. Preferably, the light incident on any position of the concave lens portion 13 is transmitted in the first direction d1 in an arbitrary time zone in which light from the sun can enter the concave lens portion 13. That is, preferably, the divergent light emitted from the concave lens portion 13 includes light traveling in the first direction d1 at an arbitrary time when light from the sun can enter the concave lens portion 13.

  The concave lens portion 13 that exerts such an optical action is determined as follows as an example. As described above, the first optical sheet 11 is installed so that the optical axis X of the concave lens portion 13 is parallel to the first direction d1 that is the longitudinal direction of the light guide path 31. On the other hand, as shown in FIG. 2, each of the lights L1 to L3 toward the focal point F of the concave lens unit 13 is refracted by the concave lens unit 13 and travels in a direction parallel to the optical axis X. Accordingly, among the light incident on each position of the concave lens portion 13 from a predetermined incident direction, the lights L1 to L3 that are incident on the respective positions of the concave lens portion 13 toward the focal point F are refracted by the concave lens portion 13 to be optical axes. It proceeds in the first direction d1 parallel to X. That is, the light incident on the concave lens portion 13 at one time and the light incident on the concave lens portion 13 at another time, preferably the light incident on the concave lens portion 13 at an arbitrary time include light directed toward the focal point F. The inclination and size of the surface of the concave lens portion 13 may be determined.

  In the example shown in FIG. 3, the concave lens portion 13 is made of a Fresnel lens. Note that, as described above, if the light incident on the concave lens unit 13 at any time when the light from the sun can enter the concave lens unit 13 includes light traveling toward the focal point F, as shown in FIG. The part 13 may be a part of a Fresnel lens.

  As shown in FIG. 3, the concave lens portion 13 specifically includes a plurality of lens surfaces 14 and a rise surface 15 that connects two adjacent lens surfaces 14. In the following description, the concave lens portion 13 is described using an example of a circular Fresnel lens, but the concave lens portion 13 may be a linear Fresnel lens.

  The illustrated Fresnel lens is expected to exhibit the same lens action as a concave lens having an optical axis X by a combination of a plurality of lens surfaces 14. Each lens surface 14 has an annular shape, and a plurality of lens surfaces 14 are arranged concentrically around the optical axis X. That is, in any cross section including the optical axis X, the plurality of lens surfaces 14 are arranged in order from the optical axis X along the first arrangement direction P1.

  As shown in FIG. 3, when the angle formed by each lens surface 14 with the sheet surface 11 c of the first optical sheet 11 is a lens angle α, the lens surface 14 arranged further away from the optical axis X is The lens angle α increases. Therefore, the optical axis X of the concave lens 12 passes through a position where the size of the lens angle α is the smallest.

  In this specification, “sheet surface (film surface, plate surface)” is the same as the planar direction of the target sheet-like member when the target sheet-like member is viewed as a whole and globally. It refers to the surface to be used. In the present embodiment, the sheet surface 11c of the first optical sheet 11 and the light incident side surface 12a of the main body 12 are parallel to each other. The normal direction nd of the sheet surface 11 c of the first optical sheet 11 is parallel to the direction in which the optical axis X of the concave lens 12 extends.

  Further, when the dimension of each lens surface 14 in the direction in which the optical axis X extends is a height h, the lens surface 14 disposed further away from the optical axis X along the arrangement direction P1 has a height h. Is getting higher. In the illustrated example, the pitch P of the lens surfaces 14 in the first arrangement direction P1 is constant.

  Further, as shown in FIG. 3, a rise surface 15 is disposed between two adjacent lens surfaces 14. Each rise surface 15 extends along the normal direction nd. The rise surface 15 is usually a surface that is not expected to have a lens action of light.

  Next, the operation of the present embodiment configured as described above will be described. In the following description, an example in which the daylighting means 10 is installed on the roof 91 in a state where the optical axis X of the concave lens portion 13 is inclined with respect to both the vertical direction and the horizontal direction will be described.

  First, as shown in FIG. 2, in the morning or evening time zone, the first optical sheet of the daylighting unit 10 emits sunlight L1 as a parallel light beam from a direction inclined vertically downward with respect to the optical axis X. 11 is incident on the entire light incident side. On the other hand, in the noon time zone, sunlight L2 enters the first optical sheet 11 as a parallel light flux from a direction inclined vertically upward with respect to the optical axis X, and is a time between morning and evening and noon. Sunlight L3 enters the first optical sheet 11 as a parallel light flux from a direction along the optical axis X to some extent. Lights L <b> 1 to L <b> 3 from the sun incident on the first optical sheet 11 in each time zone are refracted by the concave lens unit 13 and travel toward the light guide unit 30 as divergent light.

  The divergent light traveling toward the light guide means 30 has low directivity and spreads over a wide range. In particular, in the present embodiment, the concave lens unit 13 transmits light incident on any position of the concave lens unit 13 at an arbitrary time when light from the sun can enter the concave lens unit 13 in parallel with the optical axis X. Since the light travels in one direction d1, light L1 to L3 from the sun that is incident on any position of the concave lens portion 13 at an arbitrary time travels in the first direction d1. Become. Light that is refracted and passes through the concave lens portion 13 and travels in the first direction d <b> 1 travels through the light guide path 31 without being reflected by the inner surface of the light guide path 31. Since such light is not affected by reflection loss, the light can pass through the light guide path 31 extending in parallel with the first direction d1 without reducing the amount of light.

  On the other hand, the light traveling in the light guide 31 toward the direction inclined with respect to the first direction d1 travels through the light guide 31 while being reflected by the inner surface of the light guide 31. This light passes through the light guide 31 while losing a part of the light amount every time it is reflected.

  The light that has passed through these light guide paths 31 enters the connection path 32 and is guided while being reflected by the inner surface of the connection path 32. When this light reaches the diffusion plate 96 installed at the end of the connection path 32, the light is irradiated from the diffusion plate 96 into the room 95 as diffused light. Thereby, the inside of the room 95 can be illuminated uniformly.

  As described above, according to the present embodiment, by appropriately setting the inclination of the surface of the concave lens portion 13, the concave lens portion 13 travels light that is incident on one position of the concave lens portion 13 in one time. The direction and the traveling direction of light incident on another position of the concave lens portion 13 at another time are changed so as to be the first direction d1 which is the longitudinal direction of the light guide path 31. The light traveling in the first direction d1 can travel through the light guide 31 without being reflected by the inner surface of the light guide 31, and can pass through the light guide 31 without losing the amount of light. For this reason, the lighting efficiency of light can be maintained to some extent in one time zone including the one time and another time zone including the other time.

  Furthermore, by appropriately setting the inclination of the surface of the concave lens portion 13, even if the incident direction of the light incident on the concave lens portion 13 changes according to changes in time zone or season, it is guided from the concave lens portion 13. The divergent light emitted toward the light means 30 can include light traveling in the first direction d <b> 1 that is the longitudinal direction of the light guide path 31. Light that travels in the light guide path 31 in the first direction d1 that is the longitudinal direction of the light guide path 31 travels through the light guide path 31 without being reflected by the inner surface of the light guide path 31, and passes through the light guide path 31 without losing light quantity. Can pass through. Therefore, even if the incident direction of light from the sun incident on the concave lens portion 13 changes according to changes in time zone and season, the lighting efficiency of the light taken into the room 95 can be stabilized to some extent.

In addition, from the above, according to the solar light daylighting system 1 according to the present embodiment, it is possible to effectively suppress fluctuations in the daylighting efficiency depending on the season and time zone, and thereby, a stable light amount throughout the year. Sunlight can be taken. That is, by removing the problem that this type of solar lighting system 1 has in the past, it is possible to greatly contribute to energy saving and CO ₂ reduction through the widespread use of the solar lighting system 1. Further, it is not necessary to make the daylighting means 10 movable, and the complexity of the structure can be avoided.

  Moreover, according to this Embodiment, since the daylighting means 10 which has the concave lens part 13 which daylights is provided, the light L1-3 from the sun which injects into the concave lens part 13 of the daylighting means 10 is the concave lens part 13. The light is refracted and travels toward the light guide means 30 as divergent light. The divergent light traveling into the light guide unit 30 has low directivity and spreads over a wide range, so that it does not collect at one point in the light guide unit 30. For this reason, it can prevent that the light guide means 30 is damaged by the energy of light.

  Moreover, according to this Embodiment, the concave lens part 13 of the lighting means 10 consists of a Fresnel lens. In this case, since the thickness of the concave lens portion 13 can be reduced, the daylighting means 10 becomes light and the daylighting means 10 can be easily installed.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a schematic view showing a main part of the sunlight lighting system 1 according to the second embodiment of the present invention, and FIG. 6 is a sectional view showing the lighting means 10 of the sunlight lighting system 1 shown in FIG. It is. The second embodiment described with reference to FIGS. 5 and 6 is different in that the daylighting means 10 further includes a first prism array 23 between the concave lens portion 13 and the light guide path 31. The configuration can be configured similarly to the first embodiment. In the following description of the second embodiment and the drawings used in the following description, the parts that can be configured in the same manner as in the first embodiment described above are the same as the corresponding parts in the first embodiment described above. The same reference numerals as those used above will be used, and redundant explanation will be omitted.

  As shown in FIGS. 5 and 6, the sunlight lighting system 10 includes a daylighting means 10 having a concave lens 12 for daylighting, and a light guide means 30 connected to the daylighting means 10 and receiving light from the daylighting means 10. It is equipped with. In the example described below, similarly to the first embodiment shown in FIG. 1, the daylighting means 10 is attached to the roof 91 of the building 90, and the light daylighted by the daylighting means 10 enters the room 95 in the building 90. It is guided through the light guide means 30.

  As shown in FIGS. 5 and 6, the first optical sheet 11 includes a sheet-like main body portion 12 and a concave lens portion 13 disposed on the light output side surface 12 b of the main body portion 12. The first optical sheet 11 is disposed at a distance from the light guide path 31 in a state where the optical axis X of the concave lens portion 13 is inclined with respect to the first direction d1 which is the longitudinal direction of the light guide path 31.

  In the present embodiment, the concave lens unit 13 travels at least the traveling direction of light incident on one position of the concave lens unit 13 at one time and the traveling direction of light incident on another position of the concave lens unit 13 at another time. The direction is changed so as to be a second direction d2 in which the optical axis X extends. Preferably, light incident on any position of the concave lens portion 13 at an arbitrary time when light from the sun can enter the concave lens portion 13 is transmitted in the second direction d2 in which the optical axis X extends. ing. That is, preferably, the divergent light emitted from the concave lens unit 13 includes light traveling in the second direction d2 at an arbitrary time when light from the sun can enter the concave lens unit 13.

  The daylighting means 10 has a second optical sheet 21 between the concave lens portion 13 and the light guide path 31. The second optical sheet 21 is disposed at a distance from the first optical sheet 11, and the sheet surface 21 c of the second optical sheet 21 is parallel to the sheet surface 11 c of the first optical sheet 11. However, the sheet surface 21 c of the second optical sheet 21 may be inclined with respect to the sheet surface 11 c of the first optical sheet 11. In the illustrated example, the second optical sheet 21 is connected to the light guide 31 in a state in which the sheet surface 21c of the second optical sheet 21 is inclined with respect to the first direction d1 that is the longitudinal direction of the light guide 31. ing.

  As shown in FIG. 6, the second optical sheet 21 of the daylighting unit 10 includes a sheet-like main body 22 and a first prism array 23 disposed on the light output side surface 22 b of the main body 22. ing. The first prism array 23 deflects the light from the concave lens portion 13 of the first optical sheet 11 toward the light guide path 31. In the present embodiment, the first prism array 23 directs the traveling direction of light from the concave lens portion 13 of the first optical sheet 11 in the second direction d2 toward the first direction d1 that is the longitudinal direction of the light guide path 31. To change.

  As described above, the concave lens unit 13 has at least a traveling direction of light incident on one position of the concave lens unit 13 at one time and a traveling direction of light incident on another position of the concave lens unit 13 at another time. Are changed so as to be parallel to the second direction d2. The first prism array 23 changes the traveling direction of light that is refracted by the concave lens portion 13 and proceeds in the second direction d2. It is made to change to the 1st direction d1 which is the longitudinal direction of. Thereby, the daylighting means 10 guides the traveling direction of the light incident on one position of the concave lens portion 13 at one time and the traveling direction of the light incident on another position of the concave lens portion 13 at another time. It can be changed in the first direction d1, which is the longitudinal direction of the optical path 31.

  The first prism array 23 includes a plurality of first unit prisms 24 arranged along the second arrangement direction P2.

  The first unit prisms 24 constituting the first prism array 23 extend linearly in a direction orthogonal to the second arrangement direction P2 on the light output side surface 22b of the main body 22. Each first unit prism 24 protrudes from the surface 22b on the light output side of the main body 22 so as to taper away from the surface 22b. As shown in FIG. 6, the first unit prism 24 has a triangular cross-sectional shape in a cross section orthogonal to the longitudinal direction (that is, a cross section orthogonal to the second arrangement direction P2). That is, each first unit prism 24 includes a first surface 24a located on one side along the second arrangement direction P2, and a second surface 24b located on the other side along the second arrangement direction P2. have. In the illustrated example, the angle formed by the first surface 24 a with respect to the sheet surface 21 c of the second optical sheet 21 is smaller than the angle formed by the second surface 24 b with respect to the sheet surface 21 c of the second optical sheet 21. The first surface 24a is expected as a refracting surface that deflects light incident along the second direction d2 toward the first direction d1 that is the longitudinal direction of the light guide path 31.

  The first unit prisms 24 are arranged on the main body 22 without any gaps, and the light output side surface of the second optical sheet 21 is formed by the first unit prisms 24. On the other hand, the light incident side surface of the second optical sheet 21 is formed by the light incident side surface 22a of the main body 22, and is formed as a smooth surface in the illustrated embodiment.

  The “unit prism” in the present specification means an element having a function of changing the traveling direction of the light by applying an optical action such as refraction or reflection to the light, and only a difference in the designation is used. Is not distinguished from such elements as “unit lens”, “unit element”, “unit shape element”, and “unit optical element”.

  Next, the operation of the present embodiment configured as described above will be described.

  As shown in FIG. 5, in the morning or evening time zone, sunlight L <b> 11 from the direction inclined vertically downward with respect to the optical axis X is converted into a parallel light flux of the first optical sheet 11 of the daylighting means 10. Incident on the entire incident side. On the other hand, in the noon time zone, sunlight L12 enters the first optical sheet 11 as a parallel light flux from a direction inclined vertically upward with respect to the optical axis X, and the morning and evening and noon. In the intervening time zone, sunlight L13 enters the first optical sheet 11 as a parallel light flux from a direction along the optical axis X to some extent. Lights L11 to L13 from the sun incident on the first optical sheet 11 in each time zone are refracted by the concave lens portion 13 and travel toward the second optical sheet 21 as divergent light.

  The divergent light traveling toward the second optical sheet 21 has low directivity and spreads over a wide range. In particular, in the present embodiment, the concave lens unit 13 is a second lens in which the optical axis X extends the light incident on any position of the concave lens unit 13 at an arbitrary time when light from the sun can enter the concave lens unit 13. Since light is refracted in the direction d2, light L11 to L13 from the sun that is incident on any position of the concave lens portion 13 at an arbitrary time is directed in the second direction d2 in which the optical axis X extends. It will go on.

  The light transmitted through the concave lens portion 13 enters the light incident side surface of the second optical sheet 21, is deflected by the first prism array 23, and proceeds toward the light guide path 31. In particular, the light transmitted through the concave lens portion 13 and traveling in the second direction d2 is bent in the traveling direction toward the first direction d1 which is the longitudinal direction of the light guide 31 by the first prism array 23 of the second optical sheet 21. It is done.

  The light traveling in the first direction d <b> 1 in the light guide 31 travels in the light guide 31 without being reflected by the inner surface of the light guide 31. Since such light is not affected by reflection loss, the light can pass through the light guide path 31 extending in parallel with the first direction d1 without reducing the amount of light.

  On the other hand, the light passing through the first prism array 23 and traveling in the direction inclined with respect to the first direction d1 travels through the light guide 31 while being reflected by the inner surface of the light guide 31. This light passes through the light guide 31 while losing a part of the light amount every time it is reflected.

  The light that has passed through these light guide paths 31 enters the connection path 32 and is guided while being reflected by the inner surface of the connection path 32. When this light reaches the diffusion plate 96 installed at the end of the connection path 32, the light is irradiated from the diffusion plate 96 into the room 95 as diffused light.

  As described above, according to the present embodiment, by appropriately setting the inclination of the surface of the concave lens portion 13, the concave lens portion 13 can transmit light incident on one position of the concave lens portion 13 in one time. The traveling direction and the traveling direction of light incident on another position of the concave lens portion 13 at another time are changed so as to be the second direction d2, and the first prism array 23 is moved from the concave lens portion 13 to the first direction. The traveling direction of the light traveling in the two directions d2 is changed to the first direction d1 that is the longitudinal direction of the light guide path 31. The light traveling in the first direction d1 can travel through the light guide 31 without being reflected by the inner surface of the light guide 31, and can pass through the light guide 31 without losing the amount of light. For this reason, the lighting efficiency of light can be maintained to some extent in one time zone including the one time and another time zone including the other time.

  Further, by appropriately setting the surface inclination of the concave lens portion 13 and the angle of the first prism array 23, the incident direction of light from the sun incident on the concave lens portion 13 changes according to changes in time zone and season. However, the divergent light traveling from the concave lens portion 13 into the light guide path 31 via the first prism array 23 can include light traveling in the first direction d1 that is the longitudinal direction of the light guide path 31. The light traveling in the first direction d1 through the light guide 31 can travel through the light guide 31 without being reflected by the inner surface of the light guide 31, and can pass through the light guide 31 without losing the amount of light. Therefore, even if the incident direction of light from the sun incident on the concave lens portion 13 changes according to changes in time zone and season, the lighting efficiency of the light taken into the room 95 can be stabilized to some extent.

  In addition, according to the present embodiment, since the daylighting means 10 having the concave lens part 13 for daylighting is provided, the light L11 to 13 from the sun incident on the concave lens part 13 of the daylighting means 10 is the concave lens part 13. Then, the light is refracted and proceeds toward the light guide path 31 through the first prism array 23 as divergent light. The divergent light that travels into the light guide 31 has low directivity and spreads over a wide range, so that it does not collect at one point in the light guide 31. For this reason, it can prevent that the light guide path 31 of the light guide means 30 is damaged by the energy of light.

  Further, according to the present embodiment, the first prism array 23 deflects the light from the concave lens portion 13 toward the light guide path 31. In this case, the light traveling direction may be bent in the first direction d1 via the first prism array 23 without directly bending the light traveling direction in the first direction d1 that is the longitudinal direction of the light guide path 31 due to refraction at the concave lens portion 13. it can. Thereby, the freedom degree of installation of the sunlight lighting system 1 can be raised, and it can respond flexibly to the shape of the building 90, the installation space of the roof 91, and the like.

≪Modification≫
Various modifications can be made to the above-described second embodiment. Hereinafter, an example of modification will be described with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment are used for the parts that can be configured in the same manner as in the above-described second embodiment. In other words, redundant description is omitted.

  In the second embodiment described above, as shown in FIG. 5, the daylighting means 10 includes the first optical sheet 11 including the concave lens portion 13 and the second optical sheet 21 including the first prism array 23. Although an example is shown, the configuration of the daylighting unit 10 is not limited to the configuration described above. FIG. 7 shows another configuration example of the daylighting means 10. In the example illustrated in FIG. 7, the daylighting unit 10 includes an optical sheet 111, the concave lens portion 13 is provided on the light incident side surface 111 a of the optical sheet 111, and the first prism is disposed on the light output side surface 111 b of the optical sheet 111. An array 23 is provided.

  As shown in FIG. 7, as a specific configuration, the optical sheet 111 has a sheet-like main body 112. The concave lens portion 13 is disposed on the light incident side surface 112 a of the main body portion 112, and the first prism array 23 is disposed on the light exit side surface 112 b of the main body portion 12.

  According to such a form, since the concave lens portion 13 and the first prism array 23 can be provided on the single optical sheet 111, the daylighting means 10 can be configured in a compact manner, which is excellent in terms of installation space. Yes.

  In the second embodiment described above, the daylighting means 10 may further include a second prism array 26 between the concave lens portion 13 and the first prism array 23. 8 and 9 show an example in which the daylighting means 10 further includes a second prism array 26. FIG.

  In the example shown in FIGS. 8 and 9, the first optical sheet 11 is spaced from the light guide path 31 in a state where the optical axis X of the concave lens portion 13 is inclined with respect to the first direction d <b> 1 that is the longitudinal direction of the light guide path 31. It is installed with a gap. On the other hand, the second optical sheet 21 is installed at a distance from the first optical sheet 11, and the sheet surface 21 c of the second optical sheet 21 is inclined with respect to the sheet surface 11 c of the first optical sheet 11. The second optical sheet 21 is connected to the light guide path 31 in a state where the sheet surface 21 c of the second optical sheet 21 is inclined with respect to the first direction d <b> 1 that is the longitudinal direction of the light guide path 31.

  As shown in FIG. 8, the second prism array 26 is disposed on the light incident side surface 22 a of the main body 22 of the second optical sheet 21. The second prism array 26 cooperates with the first prism array 23 to deflect the light from the concave lens portion 13 and direct it toward the light guide path 31. In the present embodiment, the second prism array 26 directs the light that has advanced from the concave lens portion 13 of the first optical sheet 11 in the second direction d2 parallel to the optical axis X toward the first prism array 23. The first prism array 23 is configured to deflect the light from the second prism array 26 in the first direction d1 that is the longitudinal direction of the light guide path 31.

  As shown in FIG. 9, the second prism array 26 disposed on the light incident side surface 22a of the main body 22 includes a plurality of second unit prisms 27 arrayed along the third array direction P3. In the present embodiment, the third arrangement direction P3 of the second unit prism 27 is parallel to the second arrangement direction P2 of the first unit prism 24.

  Each of the second unit prisms 27 constituting the second prism array 26 extends linearly in a direction orthogonal to the third arrangement direction P3 on the light incident side surface 22a of the main body 22. Further, each second unit prism 27 protrudes from the light incident side surface 22a of the main body 22 so as to taper away from the surface 22a. As shown in FIG. 9, the second unit prism 27 has a triangular cross section in a cross section orthogonal to the longitudinal direction (that is, a cross section orthogonal to the third arrangement direction P3). That is, each second unit prism 27 includes a first surface 27a located on one side along the third arrangement direction P3, a second surface 27b located on the other side along the third arrangement direction P3, have. In the illustrated example, the angle formed by the first surface 27 a with respect to the sheet surface 21 c of the second optical sheet 21 is smaller than the angle formed by the second surface 27 b with respect to the sheet surface 21 c of the second optical sheet 21. The first surface 27a enters the first prism array 23 along the second direction d2 and deflects the light deflected by the first prism array 23 in the first direction d1 that is the longitudinal direction of the light guide path 31. It is expected as a refracting surface to deflect.

  According to such a form, the lights L21 to L23 transmitted through the concave lens portion 13 enter the second prism array 26 of the second optical sheet 21, and are deflected by the second prism array 26 to be deflected by the first prism array 23. Head for. The light incident on the first prism array 23 is deflected into the light guide path 31 by the first prism array 23. That is, by changing the traveling direction of the light from the concave lens portion 13 by the first prism array 23 and the second prism array 26, the light can be largely bent toward the light guide path 31.

  Here, the following simulation results will be described as a part of the simulation results and experimental results performed by the present inventors.

  First, FIGS. 10 and 11 show a model of the solar lighting system 1 as a simulation target. In this simulation model, the same configuration as that of the solar lighting system 1 described with reference to FIGS. 10 and 11 correspond to FIGS. 8 and 9, respectively, and show a part of the model dimensions.

  Regarding the daylighting means 10, the focal length of the concave lens portion 13 in the first optical sheet 11 was 50 cm, and the arrangement pitch P of the lens surfaces 14 of the concave lens portion 13 in the first arrangement direction P1 was 0.2 mm. The 1st optical sheet 11 shall be produced by shape | molding the ultraviolet curable resin of refractive index 1.55 on the surface of the base material of thickness 4mm which consists of polymethyl methacrylate resin. The size of the manufactured first optical sheet 11 was 77.7 cm in the first arrangement direction P1 and 77.7 cm in the direction orthogonal to the first arrangement direction P1.

  On the other hand, the arrangement pitch in the second arrangement direction P2 of the first unit prisms 24 and the third arrangement direction P3 of the second unit prisms 27 in the second optical sheet 21 are both 0.2 mm. Further, as shown in FIG. 11, the angle formed by the first surface 24 a of the first unit prism 24 with respect to the sheet surface 21 c of the second optical sheet 21 is 33.3 °, and the second surface of the first unit prism 24. The angle formed by 24b with respect to the sheet surface 21c of the second optical sheet 21 was 90 °. Similarly, the angle formed by the first surface 27a of the second unit prism 27 with respect to the sheet surface 21c of the second optical sheet 21 is 33.3 °, and the second surface 27b of the second unit prism 27 is the second optical sheet. The angle formed with respect to the 21 sheet surface 21c was 90 °. The second optical sheet 21 is an ultraviolet-curing type having a refractive index of 1.55 on the surface of a 4 mm-thick base material made of polymethyl methacrylate resin, using a die produced by cutting a brass plate with a diamond bite. It was produced by shaping the resin. The size of the manufactured second optical sheet 21 is 85.7 cm in the second arrangement direction P2, and the dimension in the direction orthogonal to the second arrangement direction P2 (longitudinal direction of the first unit prism 24) is 77.cm. It was 7 cm.

  Regarding the light guide means 30, as shown in FIG. 10, the light guide path 31 of the light guide means 30 was installed such that the first direction d1 which is the longitudinal direction of the light guide path 31 was oriented in the vertical direction. The length of the first direction d1, which is the longitudinal direction of the light guide path 31, is 300 cm, and the shape of the light guide path 31 in the cross section orthogonal to the first direction d1 is a hollow square whose side is 77.7 cm. The reflectance of the light guide path 31 was 95%.

  And the 2nd optical sheet 21 of the lighting means 10 was arrange | positioned so that the edge part of the upper side of the light guide 31 might be covered. The inclination angle of the second optical sheet 21 with respect to the vertical direction was 65 °. Further, the first optical sheet 11 was disposed with a space of 4 mm between the lower end of the second optical sheet 21 and the lower end of the first optical sheet 11. The inclination angle of the first optical sheet 11 with respect to the vertical direction was 40 °.

  With respect to the above model, the lighting efficiency was simulated under the condition that sunlight enters the concave lens portion 13 from an angle of 12.2 ° to 87.9 ° with respect to the vertical direction. Here, the daylighting efficiency is defined as the ratio of the amount of light passing through the light guide path 31 in the incident light to the amount of incident light directly incident on the first optical sheet 11 from the sun.

According to the simulation result, this model was able to reduce the fluctuation of the lighting efficiency depending on the season or time zone by 30% compared to the solar lighting system without the lighting means. Therefore, according to this model, it is possible to eliminate the need to use illumination means other than the sunlight lighting system 1 in a time zone with low lighting efficiency. In addition, it is possible to eliminate a sense of incongruity caused by the occurrence of light and darkness different from the outdoors. Moreover, by using sunlight collected by the sunlight lighting system 1, it is possible to contribute to energy saving and CO ₂ reduction.

DESCRIPTION OF SYMBOLS 1 Daylighting system 10 Daylighting means 11 1st optical sheet 11c Sheet surface 13 Concave lens part 14 Lens surface 15 Rise surface 111 Optical sheet 111a Light incident side surface 111b Light emission side surface 112 Main-body part 21 2nd optical sheet 21c Sheet surface 23 first prism array 24 first unit prism 26 second prism array 27 second unit prism 30 light guide means 31 light guide path 32 connection path d1 first direction d2 second direction P1 first arrangement direction P2 second arrangement direction P3 second 3 direction X optical axis

Claims (6)

  A solar daylighting system comprising daylighting means having a concave lens part for daylighting. A light guide means connected to the daylighting means for receiving light from the daylighting means;
2. The solar light daylighting system according to claim 1, wherein the light guiding unit defines an optical path parallel to a predetermined first direction at least at an end connected to the daylighting unit.   The daylighting means includes a traveling direction of light incident on one position of the concave lens portion at one time and a traveling direction of light incident on another position of the concave lens portion at another time. The solar lighting system according to claim 2, wherein the solar lighting system is changed so that The daylighting unit further includes a prism array including a plurality of unit prisms between the concave lens portion and the light guide path,
The concave lens portion has a second direction as a traveling direction of light incident on one position of the concave lens portion at one time and a traveling direction of light incident on another position of the concave lens portion at another time. Change to
The solar light collecting system according to claim 2, wherein the prism array changes a traveling direction of light traveling in the second direction from the concave lens portion to the first direction. The daylighting means has an optical sheet,
The concave lens portion is provided on the light incident side surface of the optical sheet,
The solar light collecting system according to claim 4, wherein the prism array is provided on a light output side surface of the optical sheet.   The sunlight collecting system according to any one of claims 1 to 5, wherein the concave lens portion is a Fresnel lens.

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