JP6341546B2 - Light energy time division distribution device, plant factory, building, light energy time division distribution method and rotating cylinder - Google Patents

Description

  The present invention relates to a light energy time-division distribution device, a plant factory, a building, a light energy time-division distribution method for distributing light energy of condensed sunlight or light energy of an artificial light source such as a lamp in a time division manner, and More particularly, the present invention relates to a light energy time-division distribution device, a plant factory, a building, a light energy time-division distribution method, and a rotation cylinder that have a structure for distributing incident light energy at high speed.

  Due to the recent trend of preventing global warming, the need for using renewable energy is increasing. In particular, sunlight is often applied to use in power generation using a solar power generation panel and a solar heat collector, or to use in hot water generation. In addition, sunlight has been applied to use in daylighting systems in buildings such as houses or offices.

  On the other hand, when cultivating a positive plant that requires strong light in a plant factory, the positive plant is irradiated with light such as sunlight or a high-intensity lamp. For the purpose of energy saving, there are cases where light such as sunlight and high-intensity lamps is flashed at high speed or distributed in a time-sharing manner. Further, Patent Documents 1 to 3 disclose that when plants are irradiated with light in a pulsed manner, photosynthesis of plants is accelerated.

  In this way, in addition to buildings such as houses and offices, plant factories (including solar combined type, fully artificial light type), wards, educational facilities and other buildings, or other wide uses and purposes, Development of a time division distribution device for light energy and a method for time division distribution of light energy is desired.

JP 03-059610 A Japanese Patent Publication No. 05-019129 Japanese Examined Patent Publication No. 62-006785 Japanese Patent No. 4280456

Plant Factory Research Institute, “Effects of Pulsed Light on Plant Photosynthesis”, [online], August 17, 2014, [Search December 3, 2015], Internet <URL: http: // www .sasrc.jp / pulse.htm>

As described above, strong light such as sunlight and high brightness artificial light (high photon flux density light, hereinafter referred to as high PPFD light) is rapidly blinked or time-division distributed. Despite the desire for technology, such technology has not yet been established. Here, high photon flux density (high PPFD) is about 1/10 or more (≧ about 200μmol /) of about 2000 micromol per square meter per second (unit: μmol / m ² / s) corresponding to the maximum PPFD of natural light. m ² / s) PPFD light energy. Here, “high speed” refers to a state where light blinks at a frequency of, for example, several tens of hertz and repeats light and dark, and a time width when light is distributed is, for example, about 100 microseconds or less.

  For example, Patent Documents 1 to 3 disclose a structure of time division distribution by a light distribution function by a rotating tilt mirror and a physical switching function of a joint surface between an incident side optical fiber and an emission side optical fiber. However, since these structures are complicated, it is difficult to increase the speed. In addition, since the light reflection surface is narrow, it is difficult to time-divide and distribute high PPFD light.

  On the other hand, when the light source itself uses a light-emitting diode (hereinafter referred to as LED) that can blink at high speed, the light can be intentionally blinked at high speed. By using LEDs, it is possible to achieve energy saving and longer life in plant factories. However, in a fully artificial light plant factory, it is not possible to accelerate the photosynthesis of positive plants such as tomatoes, melons and others that require strong light by using blinking of LED light. The light source of LED does not have sufficient brightness and PPFD necessary for photosynthesis of positive plants.

  In order to increase the luminance, there is a method of increasing the number of LEDs per irradiation area. However, it is necessary to take measures against heat generation due to the loss of the LED during electrical-optical conversion. In addition, a large amount of power is required to drive the light emission of many LEDs including this loss. For this reason, increasing the number of LEDs is not realistic considering profitability.

  Even if it is not only for acceleration of photosynthesis but also for energy saving, heat generation and power consumption become a problem for fluorescent lights including LEDs, sodium lamps, metal halide lamps, and other artificial lights. As described above, due to the problem of heat generation and power consumption, the method using LEDs cannot sufficiently increase the luminance and PPFD.

  In general, in a fully artificial light plant factory, the growth of semi-negative plants such as lettuce and spinach and negative plants increases, so that PPFD can be easily raised by the trade-off between heat generation and power consumption. This is because there is not.

In general, natural sunlight is used for cultivation of positive plants. If the solar radiation is too strong, it is shielded from light. Even if light is shielded to about 40%, PPFD is about 1000 (unit: μmol / m ² / s). This is at least 4 times higher than PPFD compared to irradiation from the sky of 20 centimeters of commonly used LED light sources for plant factories.

  Therefore, in order to perform high-speed blinking control of pulsed light emission when cultivating positive plants, a structure that distributes high PPFD light such as sunlight and high-intensity artificial light at high speed or time-division is required. The However, even for applications other than plant factories and plant factories, at present, there is no technology for distributing high PPFD light by flashing at high speed or by time-sharing. This is an issue.

  As another problem, as disclosed in Patent Document 1, there is a problem of heat generated on a light reflection surface when high PPFD light is distributed in a time-sharing manner.

  When high PPFD light is irradiated to a narrow area on the reflection surface, if the reflection surface does not have a function of exhausting heat, the material constituting the reflection surface may be deformed or burnt due to heat generation. That is, when high PPFD light collected in a narrow range is reflected using, for example, a rotating tilt mirror or a polygon mirror, light energy is converted into heat due to reflection loss of the material used for the reflecting surface. The converted heat causes deformation or burning of the material constituting the reflecting surface.

  As a measure for preventing the influence of this heat generation, an air cooling or water cooling or other cooling function for the purpose of discharging heat is required. For example, the light energy obtained from the light condensing function toward the sun with an area of 1 square meter on the ground surface at a latitude of 35 degrees north latitude is about 1 kilowatt-second (= 1000 joules) in total for all wavelengths. is there. Suppose that the light energy collected almost losslessly is lost by about 2% on the reflecting surface, and that this loss energy is all converted to heat on the material side. Then, the thermal energy at this time corresponds to about 20 watt seconds (= 20 joules).

  More specifically, in an aluminum cube having all sides of 5 centimeters, a reflecting surface having a reflectance of 98% is defined as a reflecting surface. The entire surface is irradiated with light energy of about 1 kilowatt second. Then, if there is no wind around the aluminum cube and it is about 20 ° C, it will generate 2% of lost energy. Theoretically, the surface temperature of aluminum reaches 160 degrees Celsius or more in about 100 minutes after irradiation. When the temperature of aluminum rises 140 degrees, the volume expands by about 1%. Therefore, the reflecting surface is deformed and affects the light reflecting performance.

  Thus, when high PPFD light is distributed in a time-sharing manner, heat generated on the light reflection surface is a problem.

  Another problem is that the configuration for distributing high PPFD light in a time-sharing manner is complicated.

  Patent Document 1 discloses that a light guide path is mechanically switched by rotating a reflector, a light guide rod used in combination with the reflector, or an optical fiber. However, as disclosed in Patent Document 1, the number of components increases as the number of time divisions increases. Therefore, the accuracy required for processing is increased.

  Furthermore, the higher the time division, the greater the shake of the rotating member, which necessitates higher accuracy of shaft processing. For this reason, it becomes difficult to balance the arrangement and mass of the component parts. Moreover, the processing accuracy and assembly accuracy of many members, such as a cross-sectional shape of a light guide path and an optical fiber, are requested | required.

  The present invention has been made to solve such a problem, and suppresses the influence of heat generation on the reflecting surface in a device that time-divides and distributes high PPFD light such as condensed sunlight and lamps. An object of the present invention is to provide a light energy time-division distribution device, a plant factory, a building, a light energy time-division distribution method, and a rotating cylinder capable of simplifying the structure of the device and time-distributing light energy at high speed. To do.

  An optical energy time division distribution device according to an embodiment is a rotating cylinder that has an outer peripheral surface and rotates about a central axis as a rotation axis, and reflects incident light incident from one direction in a first direction. A rotating cylinder having the outer peripheral surface including a reflection surface and a second reflection surface that reflects the incident light in a second direction different from the first direction, and light reflected in the first direction in a predetermined space. A first reflected light guide for guiding light to one illumination range; a second reflected light guide for guiding light reflected in the second direction to a second illumination range in a predetermined space different from the first illumination range; The cross-sectional shapes orthogonal to the rotation axis in the first reflection surface and the second reflection surface each include a predetermined part of a logarithmic spiral curve centered on the rotation axis.

  Moreover, the plant factory which concerns on one Embodiment uses the said optical energy time division distribution apparatus.

  Furthermore, the building which concerns on one Embodiment uses the said optical energy time division distribution apparatus.

  An optical energy time-division distribution method according to an embodiment is a rotating cylinder that has an outer peripheral surface and rotates about a central axis as a rotation axis, and reflects incident light incident from one direction in a first direction. A step of injecting light from the one direction into the rotating cylinder having the outer peripheral surface including a reflection surface and a second reflection surface that reflects the incident light in a second direction different from the first direction; The reflected first reflected light is guided to the first illumination range in a predetermined space, and the second reflected light reflected in the second direction is second in a predetermined space different from the first illumination range. And a cross-sectional shape perpendicular to the rotation axis of the first reflection surface and the second reflection surface is a predetermined part of a logarithmic spiral curve centered on the rotation axis, respectively. including.

  A rotating cylinder according to an embodiment is a rotating cylinder that has an outer peripheral surface and rotates about a central axis as a rotation axis, and is a first reflecting surface that reflects incident light incident from one direction in a first direction. And the outer peripheral surface including a second reflecting surface that reflects the incident light in a second direction different from the first direction, and a cross-sectional shape orthogonal to the rotation axis in the first reflecting surface and the second reflecting surface is , Each including a predetermined part of a logarithmic spiral curve centered on the rotation axis.

  According to one embodiment, the structure of the apparatus is simplified while suppressing the influence of heat generation, and the light energy time-sharing distribution device capable of time-sharing light energy at high speed, plant factory, building, light energy time A split distribution method and a rotating cylinder are provided.

It is the figure which illustrated the rotation cylinder for optical energy time division distribution which concerns on Embodiment 1, (a) is a perspective view, (b) And (c) is sectional drawing orthogonal to a rotating shaft. (A) is the figure which illustrated the incident light and reflected light with respect to the reflective surface where the logarithmic spiral curve and cross-sectional shape which concern on Embodiment 1 are a logarithmic spiral curve, (b) and (c) are implementation. It is the figure which illustrated a part of logarithmic spiral curve used for the reflective surface which concerns on the form 1. (A) And (b) is sectional drawing which illustrated the rotation cylinder which concerns on the modification of Embodiment 1. As shown in FIG. 6 is a diagram illustrating a light energy time division distribution apparatus according to Embodiment 2. FIG. It is the figure which illustrated the transition of the darkness of the irradiation range by the light energy time division distribution apparatus in Embodiment 2. FIG. It is the figure which illustrated the element for calculating the light reception energy in the collector concerning Embodiment 2, and the irradiation energy in the irradiation range. FIG. 6 is a flowchart illustrating an optical energy time division distribution method using the optical energy time division distribution apparatus according to the second embodiment. It is the figure which illustrated the optical energy time division distribution apparatus which concerns on the modification of Embodiment 2. FIG. FIG. 6 is a diagram illustrating a light energy time division distribution apparatus according to a third embodiment. FIG. 10 is a diagram illustrating a light energy time division distribution apparatus according to a fourth embodiment.

(Embodiment 1)
Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 relates to a rotating cylinder used for optical energy time-division distribution. First, the rotating cylinder according to the first embodiment will be described with reference to FIGS.

  1A and 1B are diagrams illustrating a rotating cylinder for time-division distribution of light energy according to Embodiment 1, FIG. 1A is a perspective view, and FIGS. 1B and 1C are cross sections orthogonal to a rotation axis. FIG. As shown in FIGS. 1A to 1C, the rotary cylinder 1 is a substantially cylindrical member. A shaft 2 is provided at a position corresponding to the central axis in the cylindrical shape. The shaft 2 is a member extending linearly. A direction along the axis 2 is defined as an axial direction. The direction of rotation about the axis 2 is defined as the rotation direction.

  The outer peripheral surface 3 of the rotating cylinder 1 includes a plurality of reflecting surfaces 4, for example, a plurality of first reflecting surfaces 4a and a plurality of second reflecting surfaces 4b. The plurality of first reflection surfaces 4 a and the plurality of second reflection surfaces 4 b extend in the axial direction from one end to the other end in the axial direction of the rotating cylinder 1. The 1st reflective surface 4a and the 2nd reflective surface 4b are alternately arrange | positioned the outer peripheral surface 3 along the rotation direction. Accordingly, the outer peripheral surface 3 has a striped pattern in which the first reflecting surface 4a and the second reflecting surface 4b that are elongated in the axial direction are alternately arranged along the outer periphery. The widths in the rotation direction of the first reflecting surface 4a and the second reflecting surface 4b are, for example, equal. The first reflecting surface 4 a and the second reflecting surface 4 b are adjacent to each other in the rotation direction on the outer peripheral surface 3.

  For example, six first reflective surfaces 4 a are arranged at equal intervals in the rotation direction on the outer peripheral surface 3. Six second reflecting surfaces 4b are arranged between the first reflecting surfaces 4a arranged at equal intervals. In the cross section orthogonal to the axis 2, each reflecting surface 4 is arranged in an arc portion corresponding to an angle of 30 °.

  The plurality of spokes 5 are provided so as to extend radially from the shaft 2 to the inner peripheral surface of the rotary cylinder 1. The shaft 2 and the rotary cylinder 1 are fixed by a plurality of spokes 5. The shaft 2 is connected to a motor (not shown). By driving the motor, the rotary cylinder 1 can be rotated about the shaft 2 as a rotation axis. Thus, the rotating cylinder 1 has the outer peripheral surface 3 and rotates around the central axis as a rotation axis. Note that the motor is connected to a power source via a controller, for example. Further, the controller controls the rotation of the motor while sensing the rotation of the rotary cylinder 1 with a sensor.

  Light 6, for example, line-shaped light 6 extending in the axial direction is incident on the rotating cylinder 1. Incident light enters the outer peripheral surface 3 of the rotating cylinder 1 from one direction, for example, from above. The outer peripheral surface 3 rotates with the rotation of the rotary cylinder 1. Thereby, the light 6 incident on the outer peripheral surface 3 alternately enters the first reflecting surface 4a and the second reflecting surface 4b. The first reflecting surface 4a reflects the incident light 6 in the first direction 7a. The second reflecting surface 4b reflects the incident light 6 in the second direction 7b.

  As described above, the rotating cylinder 1 includes an outer periphery including a first reflecting surface that reflects incident light incident from one direction in the first direction and a second reflecting surface that reflects incident light in a second direction different from the first direction. Has a surface. The light 8a reflected by the first reflecting surface 4a travels in the first direction 7a. The light 8b reflected by the second reflecting surface 4b travels in the second direction 7b. The light 6 is preferably high PPFD light, but is not limited thereto. LED light may be used. The cross-sectional shape orthogonal to the rotation axis of the first reflection surface 4a and the second reflection surface 4b includes a part of a logarithmic spiral curve centered on the rotation axis. The first reflecting surface 4a and the second reflecting surface 4b have shapes obtained by translating the cross-sectional shape in the axial direction.

  With reference to FIG. 2, the logarithmic spiral curve used for the first reflecting surface 4a and the second reflecting surface 4b according to the first embodiment will be described. FIG. 2A is a diagram illustrating incident light and reflected light with respect to a reflective surface having a logarithmic spiral curve and a cross-sectional shape of the logarithmic spiral curve according to the first embodiment, and FIGS. FIG. 3 is a diagram illustrating a part of a logarithmic spiral curve used for the reflecting surface according to the first embodiment.

  The logarithmic spiral curve is also called an equiangular spiral curve, and is generally expressed by the following formula (units of θ and b: radian).

  Here, the length r is the distance from the origin, the angle θ is the rotation angle of the spiral, and the coefficient a is the distance from the origin at the rotation angle θ = 0. As shown in FIG. 2, the curvature is constant at any point on the logarithmic spiral curve 9 depending on the angle b. The angle formed by the lines R11 and R21 connecting the tangent lines t1 and t2 on the logarithmic spiral curve 9 and the center O is always the angle b. Therefore, when the incident / reflection of light on the logarithmic spiral curve 9 is considered, the angle formed by the incident light I11 and the perpendicular S1 of the tangent t1 and the angle formed by the reflected light I12 and the perpendicular S1 of the tangent t1, that is, the incident angle and The reflection angle φ is derived as follows (unit of φ: radian), and is always constant at any point on the logarithmic spiral curve 9.

  In FIG. 2, the incident angle and the reflection angle from the outside of the logarithmic spiral curve 9 are shown, but the characteristics that are constant also in the incident angle and the reflection angle from the inside are the same.

  As shown in FIG. 2B, the cross-sectional shape of the first reflecting surface 4a perpendicular to the rotation axis includes a part 9a of a logarithmic spiral curve with the rotation axis as the center O. As shown in FIG. 2C, the cross-sectional shape perpendicular to the rotation axis in the second reflecting surface 4b includes a part 9b of a logarithmic spiral curve having the rotation axis as the center O. Thus, the cross-sectional shapes orthogonal to the rotation axis in the first reflection surface 4a and the second reflection surface 4b each include a part of a logarithmic spiral curve having the rotation axis as the center O.

  For example, Patent Document 4 discloses a function using this property of the logarithmic spiral curve 9. Patent Document 4 utilizes the fact that r1 and r2, which are distances of lines connecting the origins of FIG. 2, are different. Since the optical path length including the reflected light when the incident light is fixed and the logarithmic spiral curve is rotated changes according to the rotation angle, the reflection of the logarithmic spiral curve is used to change the delay time of the optical path. It is usage to do.

  In the present invention, the place where incident light is fixed and the light is incident on a line connecting the origins is the same, but for the purpose of reflecting in a plurality of directions using a plurality of logarithmic spiral curves of different curvatures, There are distinct differences in the use of logarithmic spiral curves.

  As shown in FIGS. 1B and 1C, when viewed from the axial direction, a part of the logarithmic spiral curve 9 is divided into 12 parts obtained by dividing the outer peripheral surface 3 into 30 degrees with the axis 2 as the origin. Is arranged. In the 12 portions, adjacent portions are arranged such that the signs of the curvature of the logarithmic spiral curve 9 are opposite to each other. That is, for example, the positive part of the curvature of the logarithmic spiral curve 9 is the first reflection surface 4a, and the negative part of the curvature of the logarithmic spiral curve 9 is the second reflection surface 4b. As described above, the logarithmic spiral curve having a cross-sectional shape on the second reflecting surface 4b is obtained by reversing the sign of the curvature of the logarithmic spiral curve having the cross-sectional shape on the first reflecting surface 4a.

  The cross-sectional shape of the outer peripheral surface 3 is formed with gentle peaks and valleys. The expression of gentle means that the curvature of the logarithmic spiral curve 5 is relatively small. When the curvature is small, it means that the absolute value of the angle b is relatively close to 90 °. That is, it can be paraphrased when the incident / reflection angle φ is small.

  In FIGS. 1B and 1C, when the light 6 is incident on the rotary cylinder 1 from one direction, for example, from above, the rotary cylinder 1 is rotating, so that the light 6 is reflected by the first reflecting surface 4a. And it injects into the 2nd reflective surface 4b alternately. While the light 6 is incident on the first reflecting surface 4a, the light 6 is reflected in the first direction 7a regardless of which part of the first reflecting surface 4a is incident. When the rotation of the rotary cylinder 1 causes the incident light 6 to be switched from the first reflecting surface 4a to the second reflecting surface 4b, the light 6 is reflected in the second direction 7b. While the light 6 is incident on the second reflecting surface 4b, the light 6 is reflected in the second direction 7b regardless of which part of the second reflecting surface 4b is incident.

  Thus, since the logarithmic spiral curve is used for the cross-sectional shapes of the first reflecting surface 4a and the second reflecting surface 4b, the light 6 incident on the outer peripheral surface 3 is reflected by the first reflecting surface 4a or the second reflecting surface. The light is reflected in either the first direction 7a or the second direction 7b determined by the curvature of 4b. At this time, even if the light flux of the incident light has a certain width, the width of the angle difference of the incident reflection angle φ when the curvature is relatively small is small. For this reason, the angular spread of the light 8 reflected in the reflection within the same reflecting surface is small. Therefore, the luminous flux travels as a bundle bundled in a certain fixed direction. Therefore, according to the rotation angle of the rotating cylinder 1 rotating at a constant speed, for example, the time distribution is performed so as to switch in two directions of the first direction 7a and the second direction 7b.

  In the example of FIGS. 1B and 1C, the first reflecting surface 4a and the second reflecting surface 4b are arranged so that there are six each during one rotation. Therefore, every time the rotating cylinder 1 makes one rotation, distribution is performed six times in the two directions of the first direction 7a and the second direction 7b. At this time, for example, when the rotating cylinder 1 is viewed from the first direction 7a, it appears that the light blinks six times each time the rotating cylinder 1 makes one rotation. The mirror surfaces of the logarithmic spiral curve 9 are all divided at the same 30 ° angle. Therefore, when the rotating cylinder 1 is rotating at a constant speed, the light time or dark time in the light-dark cycle is equal. The duty ratio is 50%.

  According to the rotating cylinder 1 of the present embodiment, high PPFD light such as sunlight can be distributed in a time division manner. By changing the rotation speed of the rotating cylinder 1, the time division cycle can be controlled. In addition, by increasing the rotation speed, high PPFD light can be time-divisionally distributed at high speed.

  Moreover, since the rotary cylinder 1 is rotating at high speed, the heat by reflected light is dissipated. Therefore, deformation and breakage of the rotating cylinder 1 due to heat can be suppressed. Furthermore, since the time-division distribution can be performed only by rotating the cylindrical member, the structure can be simplified.

(Modification)
Next, a modification of the first embodiment will be described.
FIGS. 3A and 3B are cross-sectional views illustrating a rotating cylinder according to a modification of the first embodiment. As shown in FIG. 3A, instead of the first reflecting surface 4a and the second reflecting surface 4b of the rotating cylinder 1, a third reflecting surface 4c and a fourth reflecting surface 4d having different curvatures may be arranged. The third reflecting surface 4c and the fourth reflecting surface 4d reflect incident light in different directions.

  As shown in FIG. 3B, in addition to the first reflecting surface 4a and the second reflecting surface 4b, the fifth reflecting surface 4e that reflects incident light in the third direction and the sixth reflecting surface in the fourth direction. A reflective surface 4f may be added. That is, the outer peripheral surface 3 includes a fifth reflecting surface and a sixth reflecting surface that reflect incident light in a third direction and a fourth direction different from the first direction and the second direction, and the fifth reflecting surface and the sixth reflecting surface. The cross-sectional shape orthogonal to the rotation axis in FIG. 5 may include portions other than the part 9a and the part 9b of the logarithmic spiral curve centered on the rotation axis.

  According to this modification, in addition to the two directions of the first direction 7a and the second direction 7b, the light energy can be time-divisionally distributed at high speed in three or more directions such as the third direction and the fourth direction. it can. Other effects are the same as those of the first embodiment.

(Embodiment 2)
Next, a second embodiment will be described. The second embodiment relates to a light energy time division distribution apparatus. With reference to FIG. 4, the structure of the optical energy time division distribution apparatus which concerns on Embodiment 2 is demonstrated. FIG. 4 is a diagram illustrating a light energy time division distribution apparatus according to the second embodiment.

  As shown in FIG. 4, the optical energy time division distribution device 20 includes a condenser 11, an incident light guide 12, a rotating cylinder 1, light receiving parts 16a and 16b, a housing 17, reflected light guides 13a and 13b, and an illuminator 14a. And 14b.

  The collector 11 condenses the light 6, for example, sunlight. The condenser 11 converts the condensed light 6 into a line shape. The condenser 11 converts the collected light 6 into continuous line-shaped light 6 or discrete line-shaped light 6. Heat generation can be reduced by making the incident light 6 linear. Further, by making the light 6 in a line shape, it is possible to suppress unevenness of the light that is time-divisionally distributed.

  The incident light guide 12 is, for example, an optical fiber cable. The incident light guide 12 guides the light 6 collected by the condenser 11 to the rotating cylinder 1. The incident light guide 12 guides the line-shaped light 6 converted by the condenser 11 to the rotary cylinder 1.

  The rotating cylinder 1 distributes the light 6 guided to the rotating cylinder 1 by the incident light guide path 12 in a time-sharing manner. As described in the first embodiment, the rotating cylinder 1 distributes the light 6 in the first direction 7a and the second direction 7b in a time-sharing manner. The rotary cylinder 1 is disposed inside the housing 17.

  The reflected light guides 13a and 13b are, for example, optical fiber cables. The reflected light guides 13a and 13b are provided with light receiving portions 16a and 16b. The reflected light guide paths 13a and 13b guide the light received by the light receiving portions 16a and 16b. The reflected light guide 13a (first reflected light guide) guides the light 8 reflected in the first direction 7a by the first reflecting surface 4a of the rotating cylinder 1 to the illumination range 15a (first illumination range). The reflected light guide 13b (second reflected light guide) guides the light 8 reflected in the second direction 7b by the second reflecting surface 4b of the rotating cylinder 1 to the illumination range 15b (second illumination range).

  The light guided to the illumination ranges 15a and 15b by the reflected light guides 13a and 13b is irradiated to the illumination ranges 15a and 15b via the illuminators 14a and 14b.

  Thus, the incident light is reflected in any direction (first direction 7a and second direction 7b) according to the reflection surface 4 (first reflection surface 4a and second reflection surface 4b) of the rotating cylinder 1. . Therefore, incident light is guided to either the reflected light guide path 13a-illuminator 14a-irradiation range 15a or the reflected light guide path 13b-illuminator 14b-irradiation range 15b. In addition, you may increase the reflective surface from which a curvature differs, and may guide in 3 or more directions.

  FIG. 5 is a diagram exemplifying light-dark transition of the irradiation range by the light energy time-division distribution device in the second embodiment. As shown in FIG. 5, in the irradiation ranges 15a and 15b on the first direction 7a side and the second direction 7b side when the rotary cylinder 1 makes one rotation, “bright” and “dark” are alternately repeated. Yes. “Bright” is when light is guided and irradiated, and “dark” indicates when light is not guided. Actually, the incident light 6 has a slight width. For this reason, when the rotating cylinder 1 rotates, when the incident light straddles the different reflecting surfaces 4, the switch is not clearly performed as shown in FIG. Here, for the sake of convenience, an ideal thin light 6 distribution state is shown.

  In FIG. 5, if the irradiation area on the reflecting surface 4 is the same, the photon flux density (PPFD) is at the same level. This is the same even when the rotating cylinder 1 performs time-division distribution in two or more directions.

  The optical energy time division distribution apparatus 20 of the present embodiment makes it possible to irradiate the PPFD light on an area larger than the light receiving area depending on conditions. On the contrary, by irradiating an area smaller than the light receiving area, depending on the conditions, the photon flux density can be set higher than that of the original light. This will be described below.

  FIG. 6 is a diagram illustrating elements for calculating the light reception energy and the irradiation energy of the irradiation range of the collector according to the second embodiment. As shown in FIG. 6, the light 6 received by the light receiving surface of the condenser 11 passes through the condenser 11, the rotating cylinder 1, the reflected light guides 13 a and 13 b, and the illuminators 14 a and 14 b, and two irradiation ranges 15 a. And 15b. The irradiation ranges 15 a and 15 b at this time repeat light and dark according to the rotation of the rotating cylinder 1. Let η1 and η2 be the pass rates in consideration of the loss of light from the condenser 11 to the irradiation ranges 15a and 15b, respectively. The duty ratio of the time during which the irradiation ranges 15a and 15b are irradiated is 50%.

  As shown in FIG. 6, the light receiving area in the collector 11 is S0, the photon flux density is D0, the light receiving energy is P0, and the average light energy coefficient is A. The irradiation area in the irradiation range 15a is S1, the photon flux density is D1, the irradiation energy is P1, and the average light energy coefficient is A. The irradiation area in the irradiation range 15b is S2, the photon flux density is D2, the irradiation energy is P2, and the average light energy coefficient is A. At this time, the following equation holds.

  The coefficient A represents the average light energy per photon flux that depends on the wavelength band distribution of light. Here, it is assumed that the wavelength band distribution does not change between light reception and irradiation. The same average light energy coefficient A is used on the light receiving side and all irradiation sides. At this time, as shown in FIG. 5, it is assumed that the ideal state in which the time-sharing distribution is clearly switched from 100% to 0% or from 0% to 100%. Then, P1 and P2 do not have energy at the same time on the time axis. Note that η0 is a total passing rate.

  Next, for the sake of simplicity, for the sake of convenience, it is assumed that the irradiation areas are the same in the irradiation ranges 15a and 15b, and that the photon flux density and the pass rate when time-sharing is distributed to either are the same in both light guides. To do. In that case, the following equation is derived.

By applying the formulas (3) to (9) and rearranging, the following three formulas are finally obtained.

  Specifically, in the case of the purpose of setting the photon flux density D0 on the light receiving surface and the photon flux density D on the irradiation side to the same photon flux density, for example, the pass rate η is an arbitrary pass rate of 50% or more. To do. Then, since D0 = D and 50% ≦ η ≦ 100%, when applied to the equation (13), the following is obtained.

  It can be seen that it is possible to irradiate a wide range of irradiation area (S1 + S2) that is larger than the original light receiving area S0. In the description so far, the case of two distribution based on FIG. 1 was considered. Here, N is further defined as a variable that represents the number of light guide paths. The conditions of the expressions (10) to (12) are expanded to the number of light guide paths N, and the expressions (13) to (15) are generalized.

  Here, the area Sm of each irradiation surface and the suffix m of the light energy Pm indicate the light guide path number and take an integer from 1 to N. Also, here, for the sake of simplicity of explanation, assuming that the time widths of the time-division-distributed light applied to each irradiation surface are all equal, the duty ratio on the time axis of the pulsed light irradiation surface is set to 1 / N. In addition, for the sake of convenience, the conditions of the equations (10) to (12) are expanded, and the passage ratios η1 to ηN of all the light guide paths are expressed as η, and the irradiation surfaces S1 to SN are all equal. .

  The effect of this embodiment is demonstrated using (17) Formula and (18) Formula. In order to make the photon flux density D on the irradiation side equal to the photon flux density D0 on the light receiving surface for a certain purpose, the following equation may be applied to the equation (17).

As a result, the following expression is obtained.

From this relational expression, it can be seen that time-division distribution can be made possible to the irradiation total area ΣSm which is (N × η) times the light receiving area S0. In other words, it can be said that a light receiving area S0 that is (1 / (N × η)) times the irradiation side total area ΣSm is sufficient. To explain the latter in detail, assuming that the photon flux density D on the irradiation side is equal to the photon flux density D0 on the light receiving surface, assuming a system with two distributions and a pass rate η of 60%, the total irradiation area ΣSm It can be seen that a light receiving area S0 of about 83.3% is sufficient.
On the other hand, in order to make the irradiation side total area ΣSm equal to the light receiving area S0, the following equation may be applied to the equation (17).

As a result, the following expression is obtained.

  From this relational expression, it can be seen that an irradiation side photon flux density D that is (N × η) times the photon flux density D0 of the light receiving surface can be obtained. This irradiation side photon flux density D is the photon flux density in the time zone in which the light irradiated as pulsed light by time division distribution is irradiated within one period. Moreover, the irradiation side photon flux density D indicates not the average photon flux density but the peak photon flux density.

  Thus, in the equation (17), the ratio of the irradiation side total area ΣSm to the light receiving area S0 (ΣSm / S0), the ratio of the photon flux density D0 of the light receiving surface to the irradiation side photon flux density D (D0 / D), and By adjusting the relationship of the product (N × η) of the number of light guides N and the light guide passage rate η (N × η), a light energy time-division distribution device applicable to various uses and purposes can be configured. 1 has a certain degree of freedom in a range where the relationship between the original light receiving area S0 of the incident light 6 and the irradiation side total area ΣSm irradiated at the tip of the reflected light 8 in FIG. It is possible because there is.

  As described above, according to the equation (17), it is possible to irradiate light having the same peak photon flux density (D0 = D) to the irradiation-side total area ΣSm of the light receiving area S0 or more depending on conditions. On the other hand, by irradiating the irradiation side total area ΣSm less than the light receiving area S0, it is possible to irradiate the peak photon flux density higher than the original light, that is, (D> D0) depending on the conditions. effective.

  According to this embodiment, it is possible to irradiate light having a photon flux density on an area larger than the light receiving area. Conversely, by irradiating an area less than the light receiving area, the photon flux density can be set higher than that of the original light.

  Further, the condenser 11 converts the condensed light 6 into line-shaped light. Thereby, heat generation can be reduced. Further, by making the light 6 in a line shape, unevenness of each time-division distributed light can be suppressed.

  Furthermore, the light energy can be time-divisionally distributed at high speed simply by making light incident on the rotated rotating cylinder 1. Therefore, it is possible to provide a simple method for distributing light energy in a time division manner. Other effects are the same as those of the first embodiment.

  Next, a light energy time division distribution method using the light energy time division distribution apparatus 20 will be described.

  FIG. 7 is a flowchart illustrating an optical energy time division distribution method using the optical energy time division distribution apparatus according to the second embodiment. First, as shown in step S10 of FIG. 7, light is collected. For example, the collector 11 collects sunlight. The condenser 11 converts the condensed light 6 into a line shape.

  Next, as shown in step S <b> 20, the condensed light is incident on the rotating cylinder 1. For example, the light 6 collected by the condenser 11 is made incident on the rotary cylinder 1 by the incident light guide path 12.

  Next, as shown in step S <b> 30, incident light is time-divided and distributed by the rotating cylinder 1. The rotary cylinder 1 has a first reflecting surface 4a and a second reflecting surface 4b. The first reflecting surface 4a reflects incident light incident from one direction in the first direction 7a. The second reflecting surface 4b reflects incident light in a second direction 7b different from the first direction 7a. In this way, the incident light 6 is time-divisionally distributed in the first direction 7a and the second direction 7b.

  Next, as shown in step S40, the light time-divisionally distributed by the rotating cylinder 1 is guided to the irradiation ranges, for example, the irradiation ranges 15a and 15b. The light reflected in the first direction is guided to the irradiation range 15a, and the light reflected in the second direction is guided to the irradiation range 15b. Each of the guided light irradiates the irradiation ranges 15a and 15b. In this way, the optical energy can be time-divisionally distributed using the optical energy time-division distribution device 20.

(Modification)
Next, a modification of the second embodiment will be described.
FIG. 8 is a diagram illustrating a light energy time division distribution apparatus according to a modification of the second embodiment. As shown in FIG. 8, in the light energy time division distribution apparatus 20a of the present modification, the light that has been time division distributed by the rotary cylinder 1 is guided to the irradiation range 15 via the reflected light guide 13 and an artificial light source. The light from 30 is guided to the irradiation range 15 via the light guide path 31. The artificial light source 30 is, for example, an LED and a metal halide lamp.

  By setting it as such a structure, the choice of the method of irradiating the illumination range 15 can be expanded. That is, when strong light is required, sunlight can be distributed in a time-sharing manner by the rotating cylinder 1 to irradiate the irradiation range 15. When weak light is required, the irradiation range 15 can be irradiated with the light from the artificial light source 30.

(Embodiment 3)
Next, a third embodiment will be described. This embodiment is an example of a plant factory using a light energy time division distribution apparatus.

  FIG. 9 is a diagram illustrating a light energy time division distribution apparatus according to the third embodiment. As shown in FIG. 9, the light energy time division distribution apparatus 30 arrange | positions the plants 40a and 40b in the irradiation ranges 15a and 15b. Then, the light 6 distributed in a time-sharing manner by the rotary cylinder 1 is irradiated to the plants 40a and 40b via the illuminators 14a and 14b. Other configurations and operations in the optical energy time division distribution apparatus 20 are the same as those in the second embodiment.

  At present, LED light sources, fluorescent lamps, sodium lamps, metal halide lamps, and other artificial lights used in fully artificial light plant factories have problems of heat generation and power consumption, and the brightness and PPFD cannot be increased sufficiently.

  On the other hand, in the present embodiment, cultivation with a photon flux density (PPFD) equivalent to that in the vicinity of the equator is possible while plant cultivation in Japan. Therefore, it is possible to cultivate positive plants, which was difficult with conventional artificial light.

  When the light-receiving surface is to obtain an irradiation-side photon flux density with a density equal to or higher than the irradiation-side photon flux density D, the irradiation-side total area ΣSm is equal to the light-receiving area S0, and the transmission rate η is divided by two distributions. Assume 60% time-sharing lighting. In this case, the following formulas (23) to (25) are applied to the formula (17).

As a result, the following expression is obtained.

  Therefore, the irradiation side photon flux density D becomes 1.2 times the photon flux density D0 of the light receiving surface. This result will be described with a more realistic example. If the place where light is received is the ground surface near 35 degrees north latitude, it means that light irradiation with a photon flux density near the equator is possible on the irradiation side. That is, when the light energy time division distribution device 30 is applied to a plant factory, it is possible to grow at a photon flux density (PPFD) having a peak illuminance equivalent to that in the vicinity of the equator while being planted in Japan. .

  However, supplementally, when applied to plant cultivation, it is necessary to assume that the photosynthesis rate of the plant with blinking light with a specific period and a specific duty ratio by time division distribution is equal to or higher than the photosynthesis rate of the plant with continuous light. To do. As a more specific example, Non-Patent Document 1 discloses the cultivation of salad vegetables. In this case, when light is intermittently irradiated with a light-dark cycle with a short interval of about 200 microseconds in duration, the rate of photosynthesis per unit light amount and the rate of growth may increase by 20-25% compared to continuous light. It is disclosed.

Thus, promoting acceleration of plant photosynthesis is also effective in preventing global warming because it also fixes CO ₂ in the atmosphere to organic matter.

  As mentioned above, the LED light source cannot set the brightness and PPFD sufficiently, so the LED light source is set close to the plant. In this case, however, the heat generated by the LED light source has an effect of burning the plant. In the light energy time-division distribution device 30 in the present embodiment, the positions of the condenser 11 and the rotating cylinder 1 can be kept away from the plant. For this reason, plant growth is not hindered.

  According to the light energy time-division distribution device 30 of the present embodiment, even in a plant factory using sunlight, it is possible to perform cultivation in the same area as a plant factory using artificial light. Consider the case of using this device in a plant factory. In order to achieve a 200 microsecond light-dark cycle that is said to speed up the growth of salad vegetables, the rotating cylinder 1 with 60 sets of two logarithmic spiral curves with different curvatures must be rotated about 83 times per second. Don't be. For this reason, high-speed rotation of the rotary cylinder 1 is required.

  In order to reduce the number of rotations of the rotating cylinder 1, the number of reflecting surfaces 4 per rotation must be increased. If an attempt is made to increase the number of reflecting surfaces 4 without changing the size of the rotating cylinder 1, the area per surface of the reflecting surface 4 decreases. For this reason, the precision of the reflective surface 4 at the time of manufacture is calculated | required. However, a sufficient area can be secured in the plant factory. Therefore, it is possible to cope with the problem by increasing the size of the rotating cylinder 1 and increasing the area per surface of the reflecting surface 4.

(Embodiment 4)
Next, a fourth embodiment will be described. The present embodiment is an example of a building using the light energy time division distribution device 40. In other words, in a building such as a house or office building, the natural light 6 is taken from the condenser 11 installed on the rooftop and distributed to a plurality of rooms, thereby reducing the power consumption of the electric lighting.

  FIG. 10 is a diagram illustrating a light energy time division distribution apparatus 40 according to the fourth embodiment. As shown in FIG. 10, the light energy time division distribution device 40 is provided in a house, for example. The condenser 11 is provided on the roof of the residential land. The light 6 collected by the condenser 11 is time-divided and distributed by, for example, the rotating cylinder 1 provided on the back of the ceiling, and guided to a plurality of rooms in the house. Rooms 18a and 18b are provided in the illumination ranges 15a and 15b. The rooms 18a and 18b are illuminated by the illuminators 14a and 14b.

  In addition, a photovoltaic power generation panel 23 is provided on the roof. The electric power generated by the solar power generation panel 23 is transmitted to the storage battery 25 through the cable 24. Thereby, the electric power stored by the storage battery 25 can be used as needed.

  Here, how the person in the rooms 18a and 18b feels the brightness of the irradiated light when the rotation speed of the rotary cylinder 1 is sufficiently high will be examined. The human eye is unaware that fluorescent and incandescent bulbs are blinking at a rate of about 100 hertz or higher. When the light / dark flashing speed in FIG. 10 is sufficiently high, the human eye does not notice the flashing. Therefore, the human eye has an illusion as if it were continuously irradiated.

  As described above, when the blinking speed is sufficiently high, the characteristic that a person recognizes brightness follows the Talbot's law. That is, it is approximately proportional to the product of the luminance of the light source and the duty ratio. The luminance of the light source in this case is the photon flux density D on the irradiation side. The duty ratio is (TL / T) in FIG. When the TLs of the respective light guide paths are all equal, the duty ratio is (1 / N).

  Therefore, the brightness perceived by a person is proportional to (D / N). That is, when the brightness of light perceived by a person on the irradiation side of the flashing light is defined as illuminance Dp (where the unit is the same as the photon flux density), the illuminance Dp is expressed by the following equation.

Here, Equation (17) is solved for the photon flux density D on the irradiation side.

This is applied to the equation (27).

  Thus, the illuminance Dp does not depend on the number of light guide paths N, but is proportional to the photon flux density D0 on the light receiving side. Here, furthermore, the ratio between the photon flux density D0 on the light receiving side and the brightness illuminance Dp felt by the person on the irradiation side is defined as the illuminance ratio B. Assume that the spectral distribution of the light wavelength does not change between the light receiving side and the irradiation side. Then, since the ratio of illuminance and the ratio of photon flux density are the same, it is as follows.

When this is applied to (29) and rearranged, the following relationship can be derived.

  Here, before the specific explanation of the industrial effects, the presupposed events will be further explained. The illuminance of electric lighting in offices is generally set between 750 and 1500 lux. On the other hand, the illuminance of sunlight around 10 am on a cloudy day at latitudes near Japan exceeds 10,000 lux. It is said that the illuminance at the brightest time in midsummer and snowy mountains is over 100,000 lux.

  In other words, the illuminance of sunlight is approximately 10 to 100 times the illuminance necessary for offices and the like. This will be described on the assumption of this phenomenon. For example, the illuminance ratio B, which is the ratio between the brightness of the light receiving surface and the brightness on the irradiation side, is set to 1/10 (= 0.1). Consider the relationship between the light receiving surface area S0 and the irradiation side total area ΣSm in a system that performs time-division distributed illumination with a passing rate η of 60%. The transmittance η is 0.6 and the illuminance ratio B is 0.1. Then, ΣSm / S0 is obtained as 6.

  That is, time-division distribution can be performed on the irradiation side total area ΣSm that is six times the area S0 of the light receiving surface. In other words, the area S0 of the light receiving surface may be one sixth of the irradiation side total area ΣSm.

  The result of the trial calculation will be described using a more specific example in a house. Using such a time-division-distributed lighting system, the total area on the irradiation side ΣSm is 60 square meters (approximately 36 tatami mats). The area S0 of the light receiving surface of the concentrator installed on the rooftop or roof necessary for this will be one-sixth of 10 square meters (approximately 6 tatami mats).

  From the specific example of the application to the lighting of the building described above, the industrial effect will be described again in two points.

  If the mechanism of time-division distributed illumination is applied to a plurality of rooms in a space where people are active as in the previous example, the light collector 11 having a light receiving area sufficiently smaller than the total area of each room can be provided. For this reason, space saving and size reduction of the concentrator 11 are attained. Therefore, it is possible to reduce the material cost and the construction cost related to the installation of the condenser 11 and the condenser 11.

  In addition, by making the concentrator 11 space-saving and miniaturizing in this way, let's collect solar energy at places where sunlight can be collected, such as the rooftop of buildings, roofs, verandas, walls, and gardens. In this case, it is not necessary to reduce the space for installing other facilities that use sunlight, such as a photovoltaic power generation panel and a solar heat collector.

  Furthermore, the time-divisionally distributed light makes it possible to suppress electric lighting in the living space. Thereby, electricity used for electric lighting can be saved. This is effective in all rooms irradiated with light ahead of the light guide. For this reason, depending on the number N of light guide paths, a relatively large energy saving can be realized by saving electric lighting as a whole.

  Supplementally, in a practical implementation of such a system that performs time-division distribution illumination, it is necessary to take measures against changes in the illuminance of sunlight depending on time, season, and weather. For example, the illuminance around midday in midsummer is about 1000 to 10,000 times the illuminance around 10 am on a cloudy day. Therefore, if it is too bright, a mechanism for dimming is necessary. Conversely, when it is dark, a mechanism to supplement the illuminance with electric lighting is necessary.

  It is desirable that these illuminance adjustments are automatically adjusted while sensing the illuminance on the light receiving side, the irradiation side, or both. In addition, in order to realize a dimming function for the purpose of reducing brightness, it is possible to regenerate if a mechanism that irradiates the panel for solar power generation and converts it to electrical energy by removing the light on the side that has been removed. This has the effect of contributing to the promotion of energy use.

  In addition, the place where the dimming function is installed is performed somewhere between the light receiving surface and the passage route of the irradiator. Installation, usage purpose, usage method, and operation of such a system that performs time-division distribution illumination It is desirable to carry out at one place or a plurality of places suitable for the maintenance method.

  Here, in addition, when the direct sunlight is blocked by clouds or flying objects, the illuminance may change greatly instantaneously. Therefore, it is desirable that the dimming mechanism and the supplementary light mechanism can sufficiently follow the assumed change rate of illuminance.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, the rotational speed of the rotating cylinder 1, the size of the rotating cylinder 1, the number of reflection surfaces, the shape, and the like can be adjusted to optimum conditions. Further, the rotary cylinder 1 is not limited to being used in a light energy time division distribution device. You may use for the apparatus which distributes light, such as a projection apparatus and a video equipment. Furthermore, the light energy time division distribution device is not limited to application to plant factories and buildings. It is applicable wherever light needs to be distributed.

DESCRIPTION OF SYMBOLS 1 Rotating cylinder 2 Shaft 3 Outer peripheral surface 4 Reflective surface 4a 1st reflective surface 4b 2nd reflective surface 4c 3rd reflective surface 4d 4th reflective surface 4e 5th reflective surface 4f 6th reflective surface 5 Spokes 6, 8, 8a, 8b Light 7a First direction 7b Second direction 9 Logarithmic spiral curves 9a, 9b Part 20, 20a, 30, 40 Light energy time division distribution device 11 Condenser 12 Incident light guides 13, 13a, 13b Reflected light guides 14a, 14b Illuminators 15a and 15b Irradiation ranges 16a and 16b Light receiving unit 17 Housing 18a 18b Room 21 Light 23 Solar power generation panel 24 Cable 25 Storage battery 30 Artificial light source 31 Light guide path 40a and 40b Plants I11 and I21 Incident light I12 and I22 Reflected light t1, t2 Tangent lines r1, r2 Distances S1, S2 Perpendicular R11, R21 Line O Center

Claims (8)

A rotating cylinder having an outer peripheral surface and rotating about a central axis as a rotation axis, wherein a first reflecting surface that reflects incident light incident from one direction in a first direction and the incident light different from the first direction A rotating cylinder having the outer peripheral surface including a second reflecting surface that reflects in two directions;
A first reflected light guide for guiding the light reflected in the first direction to a first illumination range in a predetermined space;
A second reflected light guide for guiding light reflected in the second direction to a second illumination range in a predetermined space different from the first illumination range;
With
The optical energy time-division distribution device in which the cross-sectional shapes orthogonal to the rotation axis in the first reflection surface and the second reflection surface each include a predetermined part of a logarithmic spiral curve centered on the rotation axis.   2. The light energy according to claim 1, wherein the logarithmic spiral curve of the cross-sectional shape on the second reflecting surface is obtained by reversing the sign of the curvature of the logarithmic spiral curve of the cross-sectional shape on the first reflecting surface. Split distribution device. The outer peripheral surface reflects the incident light in a third direction different from the first direction and the second direction;
A third reflected light guide for guiding the light reflected in the third direction to a third illumination range in a predetermined space different from the first illumination range and the second illumination range;
Further including
3. The optical energy time-division distribution device according to claim 1, wherein the cross-sectional shape orthogonal to the rotation axis in the third reflecting surface includes a predetermined part of the logarithmic spiral curve centered on the rotation axis. A condenser that collects the light and converts the collected light into a line-shaped light;
An incident light guide that guides the line-shaped light to the rotating cylinder;
The optical energy time division distribution apparatus according to any one of claims 1 to 3, further comprising:   The plant factory using the said optical energy time division distribution apparatus as described in any one of Claims 1-4.   The building using the said optical energy time division distribution apparatus as described in any one of Claims 1-4. A rotating cylinder having an outer peripheral surface and rotating about a central axis as a rotation axis, wherein a first reflecting surface that reflects incident light incident from one direction in a first direction and the incident light different from the first direction A step of causing light to enter from one direction into a rotating cylinder having the outer peripheral surface including a second reflecting surface that reflects in two directions;
The first reflected light reflected in the first direction is guided to the first illumination range in a predetermined space, and the second reflected light reflected in the second direction is different from the first illumination range. Guiding to the second illumination range of the space;
With
The optical energy time-division distribution method wherein cross-sectional shapes orthogonal to the rotation axis in the first reflection surface and the second reflection surface each include a predetermined part of a logarithmic spiral curve centered on the rotation axis. A rotating cylinder having an outer peripheral surface and rotating about a central axis as a rotation axis, wherein a first reflecting surface that reflects incident light incident from one direction in a first direction and the incident light different from the first direction The outer peripheral surface including a second reflecting surface that reflects in two directions,
The rotary cylinder in which the cross-sectional shapes orthogonal to the rotation axis in the first reflection surface and the second reflection surface each include a predetermined part of a logarithmic spiral curve centered on the rotation axis.