Optical duct

Abstract

This invention provides a light duct with a simple configuration that reduces the number of times sunlight is reflected while changing the direction of incoming sunlight to be horizontal. [Solution] The light duct 50, which reflects sunlight 9 taken inside and guides it to a predetermined location, has a light-collecting section 51 with an upward-facing opening 60 for collecting sunlight, and a light-guiding section 52 connected to the light-collecting section and including a horizontal section 71 that extends at least horizontally. The light-collecting section has a bottom plate 56 that slopes downward toward the north.

Description

Technical Field

[0001] The present invention relates to an optical duct.

Background Art

[0002] As a technology aimed at sending sunlight to an area far from a window in a building where sunlight is difficult to reach, an optical duct is well known. For example, Patent Document 1 discloses an eaves-type optical duct as a horizontal optical duct. The eaves-type optical duct described in Patent Document 1 includes a light collection unit that collects sunlight irradiated from the sun, a light guiding unit that guides the sunlight emitted from the light collection unit, and a light emitting unit that emits the sunlight guided by the light guiding unit as illumination light for an indoor space.

[0003] Normally, since light attenuates every time it is reflected, it is desirable to reduce the number of reflections of light in the optical duct. In particular, in a horizontal optical duct, it is desirable to change the traveling direction of the incident sunlight to be horizontal while reducing the number of reflections of the sunlight in the optical duct. In the eaves-type optical duct described in Patent Document 1, a plurality of refractors are provided that cooperate with the light collection unit to change the traveling direction of the incident sunlight to be horizontal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the horizontal optical duct described in Patent Document 1, it is necessary to prepare a plurality of refractors. In addition, it is also necessary to form a plurality of surfaces with different orientations on each refractor. Therefore, it takes time to form each refractor and the optical duct becomes complicated.

[0006] In view of the above background, the present invention aims to provide a light duct that, with a simple configuration, reduces the number of times sunlight is reflected while changing the direction of incoming sunlight to be horizontal. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides a light duct (50) that reflects sunlight (9) taken inside and guides it to a predetermined location, comprising a light-collecting section (51) having an upward-facing opening (60) for collecting the sunlight, and a light-guiding section (52) connected to the light-collecting section and including a horizontal section (71) that extends at least horizontally, wherein the light-collecting section has a bottom plate (56) that slopes downward toward the north.

[0008] According to this embodiment, the number of times sunlight is reflected can be reduced while changing the direction of the captured sunlight to be horizontal.

[0009] In the above embodiment, the light-gathering section may be provided under the floor (24) of the building (1), and the opening may be located below the floor surface.

[0010] According to this embodiment, a light duct can be installed without reducing the living space.

[0011] In the above embodiment, the bottom plate may have a first inclined portion (61) located on the south side and inclined with a first inclination angle (θ1), and a second inclined portion (62) located on the north side and inclined with a second inclination angle (θ2) smaller than the first inclination angle.

[0012] According to this configuration, even if the altitude of the sun at noon changes with the seasons, the direction of the captured sunlight can be changed to be horizontal according to each solar noon altitude.

[0013] In the above embodiment, the first inclination angle may be 15° or more and 40° or less.

[0014] According to this embodiment, sunlight from the sun at its highest point during the spring and autumn equinoxes enters the first inclined section, thereby changing the direction of the captured sunlight to horizontal.

[0015] In the above embodiment, the second inclination angle may be greater than 0° and 15° or less.

[0016] According to this embodiment, sunlight from the sun at its highest point in the sky on the winter solstice enters the second inclined section, thereby changing the direction of the captured sunlight to horizontal.

[0017] In the above embodiment, the light-gathering section further includes a top plate (58) positioned above the bottom plate, and the top plate may be inclined downward toward the north.

[0018] According to this embodiment, it is possible to capture more sunlight while suppressing an increase in the size of the opening.

[0019] In the above embodiment, the inclination angle (θ3) of the top plate may be 15° or more and 45° or less.

[0020] According to this embodiment, it is possible to capture more sunlight while suppressing an increase in the size of the opening.

[0021] In the above embodiment, the light-collecting section further comprises a top plate (58) positioned above the bottom plate and a vertical plate (57) rising upward from the southern end of the first inclined section. When sunlight is collected in the light-collecting section at a predetermined solar altitude, the light passing through the upper end of the vertical plate is defined as the first incident light (L1) when viewed from the east-west direction, the light passing through the upper end of the top plate is defined as the second incident light (L2), and the light passing through the center between the first and second incident light is defined as the third incident light (L3). The position of the connection portion may be set such that the third incident light is reflected at the connection portion between the first and second inclined sections.

[0022] According to this aspect, even if the solar altitude changes, the amount of sunlight collected can be made substantially constant.

[0023] In the above aspect, the predetermined solar altitude may be the south zenith altitude at the equinoxes.

[0024] According to this aspect, even if the south zenith altitude changes, the amount of sunlight collected can be made substantially constant.

Advantages of the Invention

[0025] The present invention can provide a light duct that, with a simple structure, reduces the number of reflections of sunlight and changes the traveling direction of the captured sunlight to be horizontal.

Brief Description of the Drawings

[0026] [Figure 1] Side cross-sectional view of a building provided with a light duct according to an embodiment [Figure 2] Side cross-sectional view showing a main part of a building provided with a light duct according to an embodiment [Figure 3] Plan view showing a main part of a building provided with a light duct according to an embodiment [Figure 4] Side cross-sectional view showing a main part of a light duct according to an embodiment [Figure 5] Side cross-sectional view showing a main part of a light duct according to an embodiment [Figure 6] Side cross-sectional view showing a main part of a light duct according to an embodiment when sunlight enters with the south zenith altitude at the equinoxes [Figure 7] Side cross-sectional view showing a main part of a light duct according to an embodiment when sunlight enters with the south zenith altitude at the winter solstice

Embodiments for Carrying Out the Invention

[0027] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following embodiment, an example will be described in which an optical duct 50 is provided in a concrete building 1 used as an apartment building. Here, "concrete construction" means that the building 1 includes a concrete slab 4 and an exterior wall 3, which are structures containing concrete. Structures containing concrete may be, for example, reinforced concrete, steel-reinforced concrete, fiber-reinforced concrete, etc.

[0028] As shown in Figure 1, Building 1 is a multi-story building having multiple levels (floors) defined by concrete slabs 4, with separate dwelling units 5 provided on the upper and lower floors of the concrete slabs 4, respectively. Multiple dwelling units 5 are provided on the same floor, and adjacent dwelling units 5 are separated from each other by concrete partition walls 6.

[0029] An opening is formed in the exterior wall 3 of building 1, and a window 7 is provided to close this opening. In this embodiment, window 7 is configured as a sliding window by a plurality of openable and closable window panels. Window 7 may be configured so that all window panels can be opened and closed, or some window panels may be configured to form a fixed window. Window 7 is located on the south side of building 1 where sunlight 8 (hereinafter referred to as sunlight 9) shines.

[0030] In the following explanation, the north-south direction perpendicular to window 7 will be defined as the front-to-back direction, the outdoor side (south side) of the north-south direction will be defined as the front, and the indoor side (north side) of the north-south direction will be defined as the rear. In addition, the width direction (east-west direction) of window 7 will be defined as the left-to-right direction.

[0031] Below the concrete slab 4, the ceiling 11 of the dwelling unit 5 is provided. The ceiling 11 has ceiling panels 12 that are spaced apart from the concrete slab 4. A space above the ceiling 13 is defined between the ceiling panels 12 and the concrete slab 4.

[0032] Above the concrete slab 4, the floor 15 of the dwelling unit 5 is provided. In this embodiment, the floor 15 of the dwelling unit 5 has a double-floor structure. As shown in Figures 2 and 3, the double-floor structure has a plurality of support legs 16 arranged on the concrete slab 4, edge joists 18 provided along the walls, and floor panels 19 arranged on the plurality of support legs 16 and edge joists 18. The plurality of support legs 16 are arranged with spacing in the front-rear and left-right directions (see Figure 3). The edge joists 18 have a plurality of legs 18a that abut the upper surface of the concrete slab 4. The legs 18a of the edge joists 18 are arranged at smaller intervals than the spacing of the support legs 16. As shown in Figure 2, the floor panels 19 may be composed of, for example, a panel board 21 arranged on the support legs 16 and edge joists 18, plywood 22 arranged on the panel board 21, and flooring 23 arranged on the plywood 22.

[0033] As shown in Figures 1 and 2, an underfloor space 24 is defined between the floor panel 19 and the concrete slab 4. The upper surface of the floor panel 19 forms the floor surface of the dwelling unit 5.

[0034] As shown in Figure 2, the floor panel 19 has an opening 25 that opens in the vertical direction. The opening 25 is rectangular when viewed from above. The opening 25 is located close to the window 7. The opening 25 has an upper opening 25A formed in the flooring 23 and a lower opening 25B formed in the plywood 22 and panel board 21. The front-to-back dimension of the upper opening 25A is larger than the front-to-back dimension of the lower opening 25B. The upper opening 25A is covered by a transparent panel material 27. The panel material 27 may be, for example, tempered glass.

[0035] A floor reinforcing structure is provided around the floor panel 19 that defines the opening 25. In this embodiment, the floor reinforcing structure is a reinforcing perimeter joist 32 provided along the edge of the opening 25. The reinforcing perimeter joist 32 has a plurality of legs 32a. As shown in Figure 3, each reinforcing perimeter joist 32 is positioned along the front and rear edges of the opening 25 when viewed from above. In other embodiments, the reinforcing perimeter joists 32 may be provided around the entire circumference of the opening 25. The reinforcing perimeter joists 32 are positioned to be added between support legs 16 that are arranged at approximately equal intervals in the front-rear direction.

[0036] As shown in Figure 1, the dwelling unit 5 has a balcony 35. The balcony 35 has an overhanging floor 36 that extends outward from the exterior wall 3 and a handrail 37 to prevent falls. The living space of the dwelling unit 5 is formed by the balcony 35, the ceiling panel 12 and the floor panel 19. In addition, the building 1 forms an indoor space inside the exterior wall 3 and an outdoor space outside the exterior wall 3. It should be noted that the light duct 50 of the present invention can also be used by placing it near a window in a building that does not have a balcony 35, or near a window in a building 1 that has a balcony 35 but does not have a balcony 35.

[0037] Dwelling unit 5 is provided with a partition wall 39 to divide the living space. The living space of dwelling unit 5 is divided by the partition wall 39, which has a door (not shown), into, for example, a room 40A with a window 7 and a washroom 40B with a washbasin 41. The partition wall 39 may be formed by, for example, a plurality of studs (not shown) extending vertically from the ceiling 11 to the floor 15 and a pair of boards 43 attached to both sides of the studs. A space 44 is formed inside the partition wall 39. An opening 46 is formed in the board 43 on the washroom 40B side of the pair of boards 43, which connects the space 44 inside the partition wall 39 to the washroom 40B.

[0038] Bathroom 40B does not have a window 7. Therefore, when the door to bathroom 40B is closed, sunlight 9 will not reach bathroom 40B.

[0039] A light duct 50 is provided in dwelling unit 5. The light duct 50 is formed in a cylindrical shape. A reflective surface is provided on the inner surface of the light duct 50. The reflective surface may be formed by the inner surface of the light duct 50, which may be mirror-finished or unfinished, or it may be formed by attaching a reflective material such as an aluminum or stainless steel plate.

[0040] The light duct 50 guides sunlight 9 taken inside to a designated room by repeatedly reflecting it off its reflective surface. In this embodiment, the light duct 50 takes in sunlight 9 in room 40A, which has a window 7, and guides the taken-in sunlight 9 to the washroom 40B.

[0041] The light duct 50 includes a light-collecting section 51 for collecting sunlight 9, a light-guiding section 52 for guiding the light collected by the light-collecting section 51 to a predetermined position, and a light-emitting section 53 for emitting the light guided by the light-guiding section 52 into the room. The light duct 50 is installed so that the entire unit is located inside the building 1. The light duct 50 is installed in each dwelling unit. Specifically, the light-collecting section 51, the light-guiding section 52, and the light-emitting section 53 are installed in the same dwelling unit 5.

[0042] As shown in Figure 2, the light-gathering section 51 is located under the floor of the building 1, i.e., in the underfloor space 24. As shown in Figure 4, the light-gathering section 51 has a base plate 56 that slopes downward toward the rear (north side), a vertical plate 57 that rises upward from the front end (south end) of the base plate 56, and a top plate 58 located above the base plate 56. The light-gathering section 51 is also formed in a plate shape facing left and right, and has a pair of side plates 59 (only one is shown in Figure 4) that connect the left and right side edges of the vertical plate 57 or the left and right side edges of the base plate 56 to the corresponding left and right side edges of the top plate 58.

[0043] The vertical plate 57 is formed in a plate shape facing the front-rear direction. The bottom plate 56 has a first inclined portion 61 that slopes downward toward the rear from the lower end of the vertical plate 57, and a second inclined portion 62 that slopes downward toward the rear from the rear edge of the first inclined portion 61. The first inclination angle θ1 of the first inclined portion 61 with respect to the front-rear direction is greater than the second inclination angle θ2 of the second inclined portion 62 with respect to the front-rear direction.

[0044] The first and second inclination angles θ1 and θ2 are set based on the solar altitude at noon. The first inclination angle θ1 is set based on the solar altitude at noon during the spring and autumn equinoxes. Specifically, the smallest first inclination angle θ1 is obtained by dividing the solar altitude at noon during the spring and autumn equinoxes in Hokkaido by 2 and then subtracting 5°, in order to horizontally reflect the sunlight at noon during the spring and autumn equinoxes in Hokkaido. The largest first inclination angle θ1 is obtained by dividing the solar altitude at noon during the spring and autumn equinoxes in Okinawa by 2 and then adding 5°. That is, the first inclination angle θ1 is set to be between 15° and 40°. Note that the angle to be subtracted or added is to give a range to the angle and is not limited to 5°.

[0045] The second tilt angle θ2 is set based on the meridian altitude at noon on the winter solstice. Specifically, the smallest second tilt angle θ2 is obtained by dividing the meridian altitude at noon on the winter solstice in Hokkaido by 2, multiplying by 0.5, and then subtracting 5° to reflect the sunlight 9 at noon on the winter solstice horizontally. The largest second tilt angle θ2 is obtained by dividing the meridian altitude at noon on the winter solstice in Okinawa by 2, multiplying by 0.5, and then adding 5°. In other words, the second tilt angle θ2 is set to be greater than 0° and less than or equal to 15°. The reason for multiplying by 0.5 is that the area of ​​the second tilt section 62 is small, and less light is reflected horizontally by the second tilt section 62.

[0046] The top plate 58 is inclined downward toward the rear. Preferably, the inclination angle θ3 of the top plate 58 with respect to the front-to-back direction is 15° or more and 45° or less. However, the inclination angle θ3 of the top plate 58 may be 15° or more and less than 90°. Alternatively, the top plate 58 may extend vertically without inclination.

[0047] As shown in Figure 3, the opening 60 is defined by the upper end of the vertical plate 57, the upper end of the top plate 58, and the upper ends of the left and right side plates 59. That is, the light-gathering section 51 has an upward-facing opening 60. The opening 60 is formed in a rectangular shape when viewed from above. The opening 60 is located below the floor surface. Specifically, the opening 60 overlaps the panel material 27 provided on the floor panel 19 when viewed from above.

[0048] The opening 60 is provided in such a manner that it does not interfere with each support leg 16. That is, the length of the opening 60 in the front-to-back direction is smaller than the distance between the support legs 16 in the front-to-back direction, and the length of the opening 60 in the left-to-right direction is smaller than the distance between the support legs 16 in the left-to-right direction. More specifically, the length of the opening 60 in the front-to-back direction is smaller than the distance between the legs 32a of the reinforcing perimeter joists 32 that are adjacent to each other in the front-to-back direction, and the length of the opening 60 in the left-to-right direction is smaller than the left-to-right length of the reinforcing perimeter joists 32.

[0049] The light-gathering section 51 is provided with flanges 63 that protrude outward from the upper ends of each plate 57, 58, and 59 that define the opening 60 of the light-gathering section 51 (see Figure 2). The opening 60 of the light-gathering section 51 is covered by a translucent plate 64 through which sunlight 9 can pass. The translucent plate 64 may be made of, for example, a transparent or translucent resin material or a glass material. The translucent plate 64 is fastened to the flanges 63 by a plurality of bolts 66 and nuts 67 (see Figure 2). This prevents dust and dirt from entering the opening 60 of the light-gathering section 51.

[0050] As shown in Figure 1, sunlight 9 passes through the panel material 27 of the floor panel 19, the opening 60 of the light-collecting section 51, and the translucent plate 64, and enters the interior of the light-collecting section 51. The sunlight 9 is tilted downward toward the indoor side (rear) and enters the indoor space. By tilting the top plate 58, it is possible to capture more sunlight 9 while suppressing an increase in the front-to-back dimension of the opening 60 of the light-collecting section 51.

[0051] As shown in Figure 5, of the sunlight 9 collected by the light-collecting section 51 at a predetermined solar altitude, the light passing through the upper end of the upright plate 57, i.e., the front end which is the southern end of the opening 60, when viewed from the left-right direction (east-west direction), is defined as the first incident light L1, and the light passing through the upper end of the top plate 58, i.e., the rear end which is the northern end of the opening 60, is defined as the second incident light L2. Furthermore, of the sunlight 9, the light passing through an intermediate position between the first incident light L1 and the second incident light L2 is defined as the third incident light L3. In other words, the distance W1 between the first incident light L1 and the third incident light L3 is equal to the distance W2 between the second incident light L2 and the third incident light L3. In this embodiment, the predetermined solar altitude is the meridian altitude at noon during the spring and autumn equinoxes. The first incident light L1, when viewed from the left-right direction, passes through the indoor end of the upper end of the upright plate 57 and is reflected by the first inclined section 61. The second incident light L2, when viewed from the left and right, passes through the outdoor end of the upper edge of the top plate 58 and is reflected by the second inclined section 62. The third incident light L3, when viewed from the left and right, is reflected at the indoor connection point between the first inclined section 61 and the second inclined section 62. In other words, the position of the connection point between the first inclined section 61 and the second inclined section 62 is set so that the third incident light L3 is reflected in this manner.

[0052] If you want to prioritize the amount of sunlight 9 taken into the horizontal section 71 on the winter solstice over the amount of sunlight 9 taken in on the spring and autumn equinoxes, the position of the connection between the first inclined section 61 and the second inclined section 62 should be set so that the second inclined section 62 becomes longer. Conversely, if you want to prioritize the amount of sunlight 9 taken into the horizontal section 71 on the spring and autumn equinoxes over the amount of sunlight 9 taken in on the winter solstice, the position of the connection between the first inclined section 61 and the second inclined section 62 should be set so that the first inclined section 61 becomes longer.

[0053] As shown in Figure 1, the light guide section 52 is formed in a rectangular cross-section. The light guide section 52 has a horizontal section 71 that extends in the front-to-back direction (horizontal direction) and is connected to the light-gathering section 51, and a vertical section 72 that extends in the up-to-down direction and is connected to the horizontal section 71.

[0054] The horizontal section 71 is located in the underfloor space 24. As shown in Figure 4, the horizontal section 71 has a lower plate 73 placed on the concrete slab 4 and an upper plate 74 placed on the lower plate 73. The horizontal section 71 also has a pair of side plates 75 (only one is shown in Figure 4) that connect the left and right side edges of the lower plate 73 to the corresponding left and right side edges of the upper plate 74. The front end (south end) of the lower plate 73 is connected to the rear end (north end) of the second inclined section 62 of the light-gathering section 51. The rear end of the lower plate 73 is inclined upward toward the rear. The front end (south end) of the upper plate 74 is connected to the rear end (north end) of the top plate 58 of the light-gathering section 51. The front end (south end) of each side plate 75 of the horizontal section 71 is connected to the rear end (north end) of the corresponding side plate 59 of the light-gathering section 51.

[0055] As shown in Figure 1, the vertical section 72 is located in the underfloor space 24 and the space 44 inside the partition wall 39. If the cross-sectional dimensions of the vertical section 72 are large, the thickness of the part of the partition wall 39 where the vertical section 72 is located may be greater than the thickness of other parts. Alternatively, the vertical section 72 may be located in a dedicated space formed outside the partition wall 39, or it may be located in a space that has a greater thickness in the north-south direction than the thickness of the partition wall 39, such as a pipe space. The vertical section 72 has a rear plate 77 extending upward from the rear end of the lower plate 73 and a front plate 78 extending upward from the rear end of the upper plate 74 of the horizontal section 71. The upper end of the front plate 78 is inclined backward toward upward. The vertical section 72 also has a pair of side plates 79 (only one is shown in Figure 1) that connect the left and right side edges of the rear plate 77 to the corresponding left and right side edges of the front plate 78.

[0056] The light-emitting section 53 is located inside the partition wall 39. The light-emitting section 53 has a lower plate 81 that extends rearward from the upper end of the rear plate 77 of the vertical section 72, and an upper plate 82 that extends rearward from the upper end of the front plate 78 of the vertical section 72. The light-emitting section 53 also has a pair of side plates 83 (only one is shown in Figure 1) that connect the left and right side edges of the lower plate 81 to the corresponding left and right side edges of the upper plate 82. The rear end of the lower plate 81, the rear end of the upper plate 82, and the rear ends of the left and right side plates 83 define a rearward-facing opening 84. When viewed from the rear, the opening 84 overlaps with an opening 46 formed in the panel material 43 on the washroom 40B side of the partition wall 39.

[0057] The opening 84 of the light-emitting section 53 is covered by a transparent or translucent resin or glass plate 85. The rear surface of the transparent plate 85 may be placed on the same plane as the panel 43 on the bathroom 40B side of the partition wall 39. Functional components that can adjust the amount of light emitted, such as shutters or blinds, may be provided in the opening 84 of the light-emitting section 53.

[0058] In the light duct 50 configured as described above, sunlight 9 passes through the window 7, the panel material 27 of the floor panel 19, the opening 60 of the light-collecting section 51, and the transmissive plate 64, and is taken into the interior of the light-collecting section 51. As shown in Figure 6, when the sun 8 is at its highest point in the sky during the spring and autumn equinoxes, sunlight 9 incident toward the first inclined section 61 of the base plate 56 is reflected by the inner surface (reflective surface) of the first inclined section 61 and taken into the light guide section 52. As shown in Figure 7, when the sun 8 is at its highest point in the sky during the winter solstice, sunlight 9 incident toward the second inclined section 62 of the base plate 56 is reflected by the inner surface (reflective surface) of the second inclined section 62 and taken into the light guide section 52. The sunlight 9 taken into the light guide section 52 is reflected by the inner surface of the horizontal section 71 and the inner surface of the vertical section 72 and taken into the light-emitting section 53. The sunlight 9 captured by the light-emitting section 53 is repeatedly reflected on the inner surfaces of each plate of the light-emitting section 53, passes through the light-transmitting plate 85 of the light-emitting section 53, and is emitted towards the washroom 40B. In this way, by tilting the bottom plate 56, the number of reflections of the sunlight 9 can be reduced while changing the direction of travel of the captured sunlight 9 to be horizontal.

[0059] The first inclined portion 61 and the second inclined portion 62 of the base plate 56 reflect sunlight 9 in this manner. In other words, the first inclined portion 61 can change the direction of sunlight 9 incident at the meridian altitude during the spring and autumn equinoxes so that it becomes horizontal. The second inclined portion 62 can change the direction of sunlight 9 incident at the meridian altitude during the winter solstice so that it becomes horizontal. Therefore, by providing two different inclination angles θ1 and θ2, even if the meridian altitude changes with the seasons, the direction of sunlight 9 incident can be changed to become horizontal according to each meridian altitude.

[0060] If the connection between the first inclined section 61 and the second inclined section 62 is on the first incident light L1 side (south side), the light-collecting section 51 can easily capture sunlight 9 from the sun 8 at its highest point in the sky during the winter solstice, but it becomes more difficult to capture sunlight 9 from the sun 8 at its highest point in the sky during the spring and autumn equinoxes. On the other hand, if the connection between the first inclined section 61 and the second inclined section 62 is on the second incident light L2 side (north side), the light-collecting section 51 can easily capture sunlight 9 from the sun 8 at its highest point in the sky during the spring and autumn equinoxes, but it becomes more difficult to capture sunlight 9 from the sun 8 at its highest point in the sky during the winter solstice. Therefore, by positioning the connection between the first inclined section 61 and the second inclined section 62 at a location where the distance W1 between the first incident light L1 and the third incident light L3 is equal to the distance W2 between the second incident light L2 and the third incident light L3, the amount of sunlight 9 taken in can be kept approximately constant even when the altitude of the sun at noon changes.

[0061] The light duct 50 is located in the underfloor space 24 and the space 44 inside the partition wall 39. Therefore, the light duct 50 can be installed without narrowing the living space. In addition, the installation of the light-gathering section 51 is made possible by providing an opening 25 in the floor panel 19. Therefore, it is not necessary to form an opening in the exterior wall 3 to provide the light-gathering section 51 outdoors. Thus, the installation of the light duct 50 is easy not only during the construction of the building 1 but also after construction.

[0062] This concludes the description of specific embodiments, but the present invention is not limited to the above embodiments or modifications and can be broadly modified and implemented. For example, in the above embodiment, the light-gathering section 51 is located in the underfloor space 24, but it may be located in the outdoor space. For example, an opening may be formed in the exterior wall 3 that connects the outdoor space and the underfloor space 24, and the horizontal section 71 of the light guide section 52 may be provided to penetrate this opening. Alternatively, in the case of a dwelling unit 5 without a balcony 35, an opening may be formed in the exterior wall 3 that connects the outdoors and the space above the ceiling 13, and the horizontal section 71 of the light guide section 52 may be provided to penetrate this opening.

[0063] The partition wall 39 on which the light-emitting section 53 is provided may separate the room 40A with the window 7 from other rooms, corridors, or other spaces. Furthermore, the light-emitting section 53 is not limited to the shape described in the above embodiment. For example, the light-emitting section 53 may be formed on the entire partition wall 39, or it may be formed on the floor surface without being raised up on the wall.

[0064] In addition, the specific configuration, arrangement, quantity, and materials of each component and part can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Furthermore, not all of the components shown in the above embodiments are essential, and can be selected as appropriate. [Explanation of Symbols]

[0065] 1: Building 9: Sunlight 24: Underfloor space (under the floor) 50: Optical duct 51: Light-gathering section 52: Light guide section 56: Bottom plate 57: Standing board 58: Tabletop 60:Aperture 61: 1st slope part 62:Second slope part 71:Horizontal part θ1: 1st inclination angle θ2: 2nd inclination angle θ3: Inclination angle

Claims

1. A light duct that reflects sunlight taken inside and guides it to a designated location, A light-collecting section having an upward-facing opening for collecting sunlight, It has a light guide section connected to the light-collecting section and including a horizontal section that extends at least horizontally, The aforementioned light-gathering section is a light duct having a bottom plate that slopes downward toward the north.

2. The light-gathering section is provided under the floor of the building, and the opening is positioned below the floor surface, as described in claim 1.

3. The optical duct according to claim 1 or claim 2, wherein the base plate is located on the south side and has a first inclined portion that is inclined with a first inclination angle, and a second inclined portion that is located on the north side and is inclined with a second inclination angle smaller than the first inclination angle.

4. The optical duct according to claim 3, wherein the first inclination angle is 15° or more and 40° or less.

5. The optical duct according to claim 3, wherein the second inclination angle is greater than 0° and 15° or less.

6. The light-gathering section further includes a top plate positioned above the bottom plate, The optical duct according to claim 1 or claim 2, wherein the top plate is inclined downward toward the north.

7. The optical duct according to claim 6, wherein the inclination angle of the top plate is 15° or more and 45° or less.

Images