Transmitting device and communication device

Abstract

To provide a transmitting device capable of transmitting a spatial optical signal that is less likely to attenuate in any direction along a horizontal plane.SOLUTION: A transmitting device 1 includes a housing 110, a top plate 11, a bottom plate 112, a light source 11 that emits illumination light 101, a spatial light modulator 12 having a modulation portion 120 irradiated with the illumination light 101 emitted from the light source 11, and an annular mirror array 15 which is a concave mirror having a concave reflecting surface 150 and which is composed of a plurality of concave mirrors arranged in a ring shape centered on the optical axis of the illumination light, and which is positioned so as to reflect modulated light 102 modulated by the modulation portion of the spatial light modulator 12 to the side as a spatial light signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a transmitting device and a communication device. [Background technology]

[0002] In optical space communications, communication is performed using optical signals (hereinafter also referred to as spatial optical signals) that propagate through space without using a medium such as an optical fiber. For example, by using a transmitting device including a phase-modulation type spatial light modulator, spatial optical signals can be transmitted in various directions by controlling the pattern set in the modulation section of the spatial light modulator. If spatial optical signals can be transmitted in multiple directions from a transmitting device, a communication network using spatial optical signals can be constructed. In general, spatial optical communications requires an adjustment mechanism to adjust the transmission and reception direction of spatial optical signals in order to transmit spatial optical signals in various directions. Therefore, when the direction of the communication target is unknown, it is necessary to visually confirm the direction of the communication target or adjust the transmission and reception direction through communication between communication devices. As such, installing communication devices that transmit and receive spatial optical signals requires effort and time.

[0003] Patent Document 1 discloses an optical transmitter / receiver for transmitting and receiving optical signals between moving vehicles. The device in Patent Document 1 includes a light-emitting unit, a light-receiving unit, and an omnidirectional optical component. The device in Patent Document 1 is configured so that the optical axis along which an optical signal emitted from the light-emitting unit enters the optical component is the same as the optical axis along which an optical signal transmitted from another vehicle and incident on the optical component exits the optical component. The device in Patent Document 1 transmits optical signals in all directions in a substantially horizontal direction externally through the optical component, and receives optical signals transmitted from other vehicles from all directions in a substantially horizontal direction. In this way, the device in Patent Document 1 performs omnidirectional transmission and reception with respect to unspecified vehicles. Furthermore, the device in Patent Document 1 transmits an optical signal transmitted from one light-emitting element toward a specific other vehicle through the omnidirectional optical component, while receiving an optical signal transmitted from the specific other vehicle. In this way, the device in Patent Document 1 performs one-to-one communication with the specific other vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-026095 Summary of the Invention [Problem to be solved by the invention]

[0005] The method of Patent Document 1 detects communication targets through omnidirectional transmission and reception, and transmits an individual optical signal (individual signal) toward the single detected communication target. In the method of Patent Document 1, the optical signal is transmitted via a rotating body having a curved, light-transmitting surface. Therefore, in the method of Patent Document 1, the beam diameter of the optical signal increases with distance from the optical transmitter / receiver depending on the curvature of the light-transmitting surface, making the optical signal prone to attenuation. On the other hand, if a plane mirror is used instead of the curved, light-transmitting surface, the attenuation of the optical signal is reduced, but the blind spot where the optical signal cannot be transmitted increases.

[0006] An object of the present disclosure is to provide a transmitting device and a communication device that can transmit a spatial optical signal that is less likely to attenuate in any direction along a horizontal plane. [Means for solving the problem]

[0007] A transmitting device according to one aspect of the present disclosure includes a light source that emits illumination light, a spatial light modulator having a modulation section onto which the illumination light emitted from the light source is irradiated, and an annular mirror array that is composed of a plurality of concave mirrors arranged in a ring shape around the optical axis of the illumination light and is positioned to reflect the modulated light modulated by the modulation section of the spatial light modulator to the side as a spatial light signal. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a transmitting device and a communication device that can transmit a spatial optical signal that is less likely to attenuate in any direction along a horizontal plane. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 2] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 3] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 4] FIG. 2 is a conceptual diagram illustrating an example of a plurality of modulation regions set in a modulation section of a spatial light modulator according to the present disclosure. [Figure 5] FIG. 1 is a conceptual diagram illustrating an example of transmission of a spatial optical signal by a transmission device according to the present disclosure. [Figure 6] FIG. 1 is a conceptual diagram illustrating an example of transmission of a spatial optical signal by a transmission device according to the present disclosure. [Figure 7] 10A and 10B are conceptual diagrams for explaining pillars of a housing of a transmitting device according to the present disclosure. [Figure 8] FIG. 1 is a conceptual diagram illustrating an example of transmission of a spatial optical signal by a transmission device according to the present disclosure. [Figure 9] FIG. 1 is a conceptual diagram illustrating an example of transmission of a spatial optical signal by a transmission device according to the present disclosure. [Figure 10] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 11] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 12] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 13] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 14] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 15] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 16] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 17] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 18]FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 19] FIG. 1 is a conceptual diagram illustrating an example of the configuration of a transmission device according to the present disclosure. [Figure 20] FIG. 1 is a conceptual diagram illustrating an example of a configuration of a communication device according to the present disclosure. [Figure 21] FIG. 2 is a conceptual diagram illustrating an example of the configuration of a receiver included in a communication device according to the present disclosure. [Figure 22] FIG. 1 is a conceptual diagram illustrating an example of a configuration of a communication device according to the present disclosure. [Figure 23] FIG. 10 is a conceptual diagram for explaining an application example of the present disclosure. [Figure 24] FIG. 2 is a block diagram illustrating an example of a configuration of a transmission device according to the present disclosure. [Figure 25] FIG. 2 is a block diagram illustrating an example of a hardware configuration for executing control and processing in the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the embodiments described below are limited in a manner that is technically preferable for carrying out the present invention, but the scope of the invention is not limited to the following. In all drawings used to describe the following embodiments, the same reference numerals are used for similar parts unless otherwise specified. Furthermore, in the following embodiments, repeated explanations of similar configurations and operations may be omitted.

[0011] In all the drawings used to explain the following embodiments, the direction of the arrows in the drawings is merely an example and does not limit the direction of light or signals. Furthermore, the lines showing the trajectories of light in the drawings are conceptual and do not accurately represent the actual direction or state of light. For example, in the drawings, changes in the direction or state of light due to refraction, reflection, diffusion, etc. at the interface between air and a substance may be omitted, or a light beam may be represented by a single line. Furthermore, cross sections may not be hatched to illustrate an example of a light path or to avoid overcrowding the configuration.

[0012] (First embodiment) First, a transmitting device according to a first embodiment will be described with reference to the drawings. The transmitting device of this embodiment is used for optical space communication in which an optical signal propagating through space (hereinafter also referred to as a spatial optical signal) is transmitted and received. The transmitting device of this embodiment may be used for applications other than optical space communication, as long as it transmits light propagating through space. Note that the drawings used in the description of this embodiment are conceptual and do not accurately depict the actual structure.

[0013] (composition) 1 to 3 are conceptual diagrams showing an example of the configuration of a transmitting device according to the present disclosure. The transmitting device 1 includes a light source 11, a spatial light modulator 12, an annular mirror array 15, and a communication controller 19. The light source 11, the spatial light modulator 12, and the annular mirror array 15 constitute a transmitter. The transmitter is housed inside a housing 110 having a window W for transmitting a spatial optical signal.

[0014] FIG. 1 is a conceptual diagram of the internal configuration of a transmitting device according to the present disclosure, seen from a side perspective. FIG. 1 shows a housing 110 cut along a cutting line passing through a window W. FIG. 1 is conceptual and does not accurately represent the shape of each component, the positional relationship between the components, the propagation of light, etc. Furthermore, the configuration in FIG. 1 may be arranged upside down. FIG. 1 also shows a top plate 111 that supports a light source 11 and an annular mirror array 15. FIG. 1 also shows a bottom plate 112 on which a spatial light modulator 12 is disposed.

[0015] FIG. 2 is a conceptual diagram of the top plate of a transmitting device according to the present disclosure, viewed from below. A through-hole T is formed in the center of the top plate 111. The through-hole T is an opening for allowing the illumination light 101 emitted from the light source 11 to pass downward. In the example of FIG. 2, the opening shape of the through-hole T is rectangular, but the opening shape of the through-hole T does not have to be rectangular. An annular mirror array 15 is disposed on the underside of the top plate 111. The annular mirror array 15 is a mirror array in which multiple concave mirrors are arranged in an annular shape. The multiple concave mirrors that make up the annular mirror array 15 are arranged in an annular shape centered on the optical axis of the illumination light 101 emitted from the light source 11. The reflective surfaces 150 of the multiple concave mirrors that make up the annular mirror array 15 are all oriented in different directions.

[0016] 3 is a conceptual diagram of the bottom plate of a transmitting device according to the present disclosure, viewed from above. A spatial light modulator 12 is disposed in the center of the bottom plate 112. A modulation section 120 of the spatial light modulator 12 faces the light source 11.

[0017] The light source 11 emits illumination light 101. The emission surface of the light source 11 is directed toward the modulation unit 120 of the spatial light modulator 12 through a through-hole T in the top plate 111. The light source 11 may be disposed inside the through-hole T in the top plate 111. The light source 11 may be disposed on the lower surface of the top plate 111 or between the top plate 111 and the spatial light modulator 12. In this case, the through-hole T does not need to be formed in the top plate 111. The illumination light 101 emitted from the light source 11 passes through the through-hole T and is irradiated onto the modulation unit 120 of the spatial light modulator 12.

[0018] The light source 11 includes multiple emitters (not shown). The emitters included in the light source 11 emit laser light in a predetermined wavelength band under the control of the communication controller 19. The wavelength of the laser light emitted from the emitter is not particularly limited and may be selected depending on the application. For example, the emitter emits laser light in the visible or infrared wavelength band. For example, near-infrared light in the 800 to 1000 nanometer (nm) range can be of a higher laser class than visible light, thereby improving sensitivity compared to visible light. For example, infrared light in the 1.55 micrometer (μm) wavelength band can use a higher-power laser light source than near-infrared light in the 800 to 1000 nm range. Laser light sources that emit infrared light in the 1.55 μm wavelength band can include aluminum gallium arsenide phosphide (AlGaAsP)-based laser light sources and indium gallium arsenide (InGaAs)-based laser light sources. The longer the wavelength of the laser light, the larger the diffraction angle and the higher the energy can be set. The light source 11 may be realized by a surface-emitting laser. The light source 11 is realized by a PCSEL (Photonic Crystal Surface Emitting Laser) type laser. The PCSEL type laser emits laser light with a circular narrow radiation, so a collimator is not required.

[0019] The spatial light modulator 12 is a phase modulation type spatial light modulator. The spatial light modulator 12 has a modulation section 120. A plurality of modulation regions are set in the modulation section 120. For example, the number of modulation regions set in the modulation section 120 is set in accordance with the number of emitters included in the light source 11.

[0020] FIG. 4 is a conceptual diagram showing an example of multiple modulation regions set in the modulation section of the spatial light modulator according to the present disclosure. For example, the modulation section 120 has modulation regions R set according to the number of emitters included in the light source 11. The number of modulation regions R set in the modulation section 120 is set arbitrarily. In the example of FIG. 4, six modulation regions R (R1 to R6) are set. Dead zones may be set between adjacent modulation regions R. For example, a black lattice-shaped phase image is set in the dead zone. The dead zone may be set in the modulation section 120 in any shape other than a lattice. Typically, a composite image is set in the modulation section 120, which is a composite of a phase image and a virtual lens image for forming a desired image. The virtual lens image is a pattern for focusing the desired image at a position at a desired distance. The modulated light 102 modulated by the modulation section 120 is focused at a position at the desired distance by the virtual lens image. For example, if a virtual lens image that acts like a cylindrical lens is used, it is possible to project linear projection light 105. Since linear projection light 105 can concentrate energy, it is possible to project projection light 105 over a long distance.

[0021] Each of the multiple modulation regions R is associated with one of the multiple emitters included in the light source 11. A pattern (also called a phase image) corresponding to an image displayed by the projected light 105 is set in each of the multiple modulation regions R under the control of the communication controller 19. Each of the multiple modulation regions R is irradiated with illumination light 101. The illumination light 101 originates from a laser light emitted from an emitter associated with the modulation region R. The illumination light 101 incident on each of the multiple modulation regions R is modulated according to the pattern (phase image) set in each of the multiple modulation regions R. The modulated light 102 modulated in each of the multiple modulation regions R travels toward the reflecting surface 150 of the annular mirror array 15.

[0022] The modulation region R is divided into multiple regions (also called tiling). For example, the modulation region R is divided into square or rectangular regions (also called tiles). Each of the multiple tiles is composed of multiple pixels. A phase image corresponding to the image to be projected is set in each of the multiple tiles. The same phase image is tiled in each of the multiple tiles assigned to the modulation region R. For example, a pre-generated phase image is set in each of the multiple tiles. When illumination light 101 is irradiated onto the modulation region R with the same phase image set in the multiple tiles, modulated light 102 that forms an image corresponding to the phase image is emitted. The more tiles set in the modulation region R, the clearer the image that can be displayed. On the other hand, a decrease in the number of pixels in each tile results in a decrease in resolution. Therefore, the size and number of tiles set in the modulation region R are set according to the application.

[0023] For example, the spatial light modulator 12 is realized by a spatial light modulator using ferroelectric liquid crystal, homogeneous liquid crystal, vertically aligned liquid crystal, or the like. For example, the spatial light modulator 12 can be realized by LCOS (Liquid Crystal on Silicon). The spatial light modulator 12 may also be realized by MEMS (Micro Electro Mechanical System). In the phase modulation type spatial light modulator 12, the energy can be concentrated on the image portion by operating to sequentially switch the location where the projection light 105 is projected. Therefore, when the phase modulation type spatial light modulator 12 is used, if the output of the emitter included in the light source 11 is the same, the image can be displayed brighter than with other methods.

[0024] The modulated light 102 modulated by the modulation section 120 of the spatial light modulator 12 travels toward the reflecting surface 150 of the annular mirror array 15. The modulated light 102 traveling toward the reflecting surface 150 of the annular mirror array 15 is reflected by the reflecting surface 150 and projected as projected light 105.

[0025] The annular mirror array 15 is configured with multiple concave mirrors arranged in a circular ring shape. The concave mirror has a concave reflecting surface 150. The reflecting surface 150 of the concave mirror is formed by a free-form surface. Arranging multiple concave mirrors in a ring allows a wider area to be covered with fewer mirrors than arranging multiple plane mirrors in a ring shape. The eight concave mirrors that make up the annular mirror array 15 are arranged in a ring shape with their reflecting surfaces 150 facing diagonally downward. The number of concave mirrors that make up the annular mirror array 15 is not limited to eight.

[0026] The annular mirror array 15 is irradiated with a light component to be projected (also referred to as desired light) of the modulated light 102 modulated by the modulation unit 120 of the spatial light modulator 12. The modulated light 102 irradiated onto the reflecting surface 150 is reflected by the reflecting surface 150. The light reflected by the reflecting surface 150 (projected light 105) is projected as a spatial light signal. The reflecting surface 150 of the annular mirror array 15 is directed in a 360-degree direction in the horizontal plane. Therefore, by using the transmitting device 1, the projected light 105 can be projected in a 360-degree direction in the horizontal plane by controlling the pattern (phase image) set in the modulation unit 120 of the spatial light modulator 12. The projected light 105 is projected in a direction along the horizontal plane. The propagation axis of the projected light 105 only needs to be along the horizontal plane, and does not need to be completely parallel to the horizontal plane.

[0027] FIG. 5 is a conceptual diagram illustrating an example of transmitting a spatial optical signal by a transmitting device according to the present disclosure. FIG. 5 is a conceptual diagram illustrating an example of transmitting a spatial optical signal in multiple directions by reflecting illumination light emitted from multiple emitters included in a light source with different concave mirrors. FIG. 5 is a view of the tabletop viewed from below. The transmitting device 1 can simultaneously transmit spatial optical signals (projected light 105) toward communication targets located in multiple directions by associating multiple modulation regions R set in the modulation unit 120 with different concave mirrors. For example, in a mode for communicating with multiple communication targets, the transmitting device 1 associates multiple modulation regions R set in the modulation unit 120 with different concave mirrors. With such association, the transmitting device 1 can individually transmit spatial optical signals toward each of multiple communication targets located in multiple directions.

[0028] FIG. 6 is a conceptual diagram illustrating an example of transmitting a spatial optical signal by a transmitting device according to the present disclosure. FIG. 6 is a conceptual diagram illustrating an example of transmitting a spatial optical signal in one direction by reflecting modulated light derived from illumination light emitted from multiple emitters included in a light source by a single concave mirror. FIG. 6 is a view of the tabletop viewed from below. For example, in a mode for searching for a communication target, the transmitting device 1 associates multiple modulation regions R set in the modulation unit 120 with a single concave mirror. This association allows the transmitting device 1 to transmit a spatial optical signal composed of multiple light beams toward the reflection direction of the reflective surface of the concave mirror. According to the transmission control shown in FIG. 6, transmitting a spatial optical signal composed of multiple light beams increases the probability that the light beams will hit the communication target, thereby improving the detection speed of the communication target. The transmitting device 1 may also be controlled to transmit a multiplexed spatial optical signal (projected light 105) toward a single communication target. When transmitting a multiplexed spatial optical signal, the transmitting device 1 sets a phase image in which modulated light 102 derived from illumination light 101 is irradiated onto a part of the reflecting surface of the concave mirror in the modulation section 120 of the spatial light modulator 12. In this way, a multiplexed spatial optical signal can be transmitted to a single communication target.

[0029] The communication controller 19 controls the light source 11 and the spatial light modulator 12. For example, the communication controller 19 is realized by a microcomputer including a processor and a memory. The communication controller 19 sets a phase image corresponding to the image to be projected in the modulation unit 120. The communication controller 19 sets the phase image corresponding to the image to be projected in the modulation area set in the modulation unit 120 of the spatial light modulator 12. The phase image of the image to be projected may be stored in advance in a storage unit (not shown). There are no particular limitations on the shape or size of the image to be projected.

[0030] The communication controller 19 controls the spatial light modulator 12 so as to change a parameter that determines the difference between the phase of the illumination light 101 irradiated onto the modulation unit 120 and the phase of the modulated light 102 reflected by the modulation unit 120. The method of driving the spatial light modulator 12 by the communication controller 19 is determined depending on the modulation method of the spatial light modulator 12. The communication controller 19 drives the light source 11 in a state where a phase image corresponding to an image to be displayed is set in the modulation unit 120 of the spatial light modulator 12. As a result, the illumination light 101 emitted from the light source 11 is irradiated onto the modulation unit 120 in a state where the phase image is set in the modulation unit 120. The illumination light 101 irradiated onto the modulation unit 120 is modulated in the modulation unit 120.

[0031] Furthermore, the communication controller 19 modulates the illumination light 101 emitted from the light source 11 for communication with a communication target (not shown). In communication, the communication controller 19 controls the timing at which the illumination light 101 is emitted from the light source 11, with a phase image for communication set in the modulation unit 120 of the spatial light modulator 12. The illumination light 101 is modulated by such control. The modulation pattern of the illumination light 101 in communication is set arbitrarily.

[0032] [Send example] Next, an example of transmitting a spatial optical signal by the transmitting device 1 of this embodiment will be described with reference to the drawings. Here, an example of transmitting a spatial optical signal while avoiding the pillars of the housing 110 will be described.

[0033] Fig. 7 is a conceptual diagram for explaining the pillars of the housing of the transmitter device according to the present disclosure. Fig. 7 is a view of the housing according to the present disclosure as seen from an obliquely upward perspective. A pillar P for fixing the upper and lower parts of the housing 110 is installed in the portion of the housing 110 where the window W is formed. For example, wiring for supplying electricity to components that require electricity is arranged on the pillar P.

[0034] 8 and 9 are conceptual diagrams showing an example of transmission of a spatial optical signal by a transmitting device according to the present disclosure. FIGS. 8 and 9 are views of the top plate of a transmitting device according to the present disclosure viewed from below. With normal projection control, a portion of the light reflected by the reflective surface 150 of the annular mirror array 15 is blocked by a pillar P. FIG. 8 shows an example in which projected light 105 reflected by the same reflective surface 150 is crossed to avoid the pillar P. FIG. 9 shows an example in which the projection direction of the projected light 105 reflected by the same reflective surface 150 is expanded to avoid the pillar P. To expand the projection direction of the projected light 105 as shown in FIG. 9, it is preferable to arrange multiple concave mirrors so that the seam between two adjacent concave mirrors overlaps the position of the pillar P.

[0035] (Variation) Next, a modification of this embodiment will be described with reference to the drawings. This modification includes a photodetector that monitors the power of the spatial optical signal.

[0036] FIG. 10 is a conceptual diagram showing an example of the configuration of a transmitting device according to the present disclosure. FIG. 10 is a conceptual diagram of the top plate of the transmitting device according to the present disclosure viewed from below. FIG. 10 is a cross-sectional view of the transmitting device 1 taken along a section passing through the pillar. A photodetector 14 is disposed inside the pillar P. The photodetector 14 is configured to irradiate modulated light 102 derived from laser light emitted from all emitters included in the light source 11. The photodetector 14 is configured to monitor the modulated light 102 derived from laser light emitted from each of the multiple emitters included in the light source 11. Also, a detection mirror 18 is disposed corresponding to the pillar P, and reflects the modulated light 102 modulated by the modulation unit 120 of the spatial light modulator 12 to the light receiving unit of the photodetector 14. If the photodetector 14 is configured to receive the modulated light 102 reflected by the reflecting surface 150 of the annular mirror array 15, the detection mirror 18 can be omitted. The following describes an optical power measurement mode for monitoring the power of a spatial optical signal.

[0037] In the optical power measurement mode, at least one of the multiple emitters included in the light source 11 is the target for optical power measurement. Modulated light 102 for measuring optical power is reflected by the reflecting surface 180 of the detection mirror 18 and irradiated onto the photodetector 14. The photodetector 14 converts the irradiated modulated light 102 into an electrical signal. The electrical signal converted by the photodetector 14 is output to the communication controller 19. The communication controller 19 measures the optical power of the modulated light 102 based on the electrical signal output from the photodetector 14.

[0038] The photodetector 14 is a light-receiving element that receives light in the wavelength region of the modulated light 102, the optical power of which is to be measured. For example, the photodetector 14 is sensitive to light in the visible region. For example, the photodetector 14 is sensitive to light in the infrared region. The photodetector 14 is sensitive to light with a wavelength in the 1.5 μm (micrometer) band, for example. Note that the wavelength band of light to which the photodetector 14 is sensitive is not limited to the 1.5 μm band. The wavelength band of light received by the photodetector 14 can be set arbitrarily to match the wavelength of the spatial optical signal to be received. The wavelength band of light received by the photodetector 14 may be set to, for example, the 0.8 μm band, the 1.55 μm band, or the 2.2 μm band. The wavelength band of light received by the photodetector 14 may also be, for example, the 0.8 to 1 μm band.

[0039] For example, the photodetector 14 can be realized by an element such as a photodiode or a phototransistor. For example, the photodetector 14 can be realized by an avalanche photodiode. However, the photodetector 14 may be realized by an element other than a photodiode, a phototransistor, or an avalanche photodiode, as long as it can convert an optical signal into an electrical signal.

[0040] In the optical power measurement mode, the communication controller 19 actually measures the optical intensity of the spatial optical signal (projected light 105). The timing of transitioning to the optical power measurement mode is set arbitrarily. In the optical power measurement mode, the communication controller 19 sets a pattern (phase image) for emitting modulated light 102 in the direction of the detection mirror 18 in the modulation unit 120 of the spatial light modulator 12. The communication controller 19 measures the optical power of the modulated light 102 using an electrical signal output from the photodetector 14 in response to the irradiation of the modulated light 102. The communication controller 19 adjusts the output of the light source 11 in accordance with the measured optical power. For example, the communication controller 19 adjusts the output of the light source 11 so that it falls within a predetermined output range. The output range of the light source 11 is not particularly limited. For example, the output range of the light source 11 is set according to standards set by law. In this way, if the photodetector 14 is placed inside the pillar P, the inside of the pillar P, which could otherwise be wasted space, can be effectively utilized.

[0041] As described above, the transmitting device of this embodiment includes a light source, a spatial light modulator, an annular mirror array, and a communication controller. The light source emits illumination light. The spatial light modulator has a modulation section onto which the illumination light emitted from the light source is irradiated. The annular mirror array is composed of a plurality of concave mirrors arranged in an annular shape centered on the optical axis of the illumination light. The annular mirror array is positioned so that the modulated light modulated by the modulation section of the spatial light modulator is reflected sideways as a spatial light signal. The communication controller sets a phase image to be used for spatial optical communication in the modulation section of the spatial light modulator. The communication controller controls the light source so that illumination light is irradiated onto the modulation section onto which the phase image is set.

[0042] The transmitting device of this embodiment includes an annular mirror array composed of multiple concave mirrors. The annular mirror array is composed of concave mirrors with reflective surfaces having a larger radius of curvature than an annular mirror composed of a single reflective surface, and therefore can suppress the spread of the projection angle in the horizontal plane. Furthermore, the annular mirror array is composed of concave mirrors with reflective surfaces having a larger radius of curvature than an annular mirror array composed of multiple plane mirrors, and therefore can suppress the spread of the projection angle compared to an annular mirror array composed of multiple plane mirrors. In other words, the transmitting device of this embodiment can transmit a spatial optical signal that is less likely to be attenuated in any direction along the horizontal plane.

[0043] In one aspect of this embodiment, the light source has multiple emitters. The communication controller sets multiple modulation regions in the modulation section of the spatial light modulator corresponding to the multiple emitters. In a mode for searching for a communication target, the communication controller sets a phase image in the modulation section of the spatial light modulator, in which modulated light modulated by the multiple modulation regions is irradiated onto a single concave mirror among the multiple concave mirrors constituting the annular mirror array. That is, in this aspect, in the mode for searching for a communication target, the modulated light modulated by the multiple modulation regions is transmitted as a spatial optical signal by the single concave mirror. According to this aspect, by searching for a communication target using a spatial optical signal composed of multiple light beams, the detection accuracy of a communication target located in the reflection direction of the reflective surface of the concave mirror is improved.

[0044] In one aspect of this embodiment, a communication controller associates each of the multiple concave mirrors constituting the annular mirror array with one of multiple communication targets. The communication controller sets a phase image in the modulation section of the spatial light modulator, in which modulated light modulated by one of the multiple modulation regions is irradiated onto each of the concave mirrors associated with one of the multiple communication targets. That is, in this aspect, modulated light modulated by each of the multiple modulation regions is transmitted as a spatial optical signal by each of the multiple concave mirrors. According to this aspect, it is possible to communicate with multiple communication targets simultaneously using the spatial optical signal for each communication target.

[0045] In one aspect of this embodiment, a communication controller, in a mode for communicating with a communication target, associates at least one of the multiple concave mirrors constituting the annular mirror array with a single communication target. The communication controller sets, in the modulation section of the spatial light modulator, a phase image in which modulated light modulated by multiple modulation regions is irradiated onto the concave mirror associated with the single communication target. That is, in this aspect, modulated light modulated by the multiple modulation regions is transmitted as a spatial optical signal by a single concave mirror. According to this aspect, spatially multiplexed communication can be realized by simultaneously transmitting multiple spatial optical signals to a single communication target.

[0046] A transmitting device according to one aspect of this embodiment includes a photodetector disposed on one side of a plurality of concave mirrors constituting an annular mirror array. In an optical power measurement mode, a communication controller sets, in the spatial light modulator, a phase image that causes modulated light modulated by a modulation unit of the spatial light modulator to be irradiated toward the photodetector. The communication controller measures the optical power of the modulated light detected by the photodetector. The communication controller adjusts the output of the light source according to the measured optical power of the modulated light. According to this aspect, the output of the light source can be adjusted according to the optical power of the actually emitted illumination light.

[0047] (Second embodiment) Next, a transmitting device according to a second embodiment will be described with reference to the drawings. The transmitting device according to this embodiment differs from the transmitting device according to the first embodiment in that it includes a relay mirror that reflects the modulated light modulated by the modulation section of the spatial light modulator.

[0048] (composition) 11 to 13 are conceptual diagrams showing an example of the configuration of a transmitting device in the present disclosure. The transmitting device 2 includes a light source 21, a spatial light modulator 22, a relay mirror 23, an annular mirror array 25, and a communication controller 29. The light source 21, the spatial light modulator 22, the relay mirror 23, and the annular mirror array 25 constitute a transmitter. The transmitter is housed inside a housing 210 having a window W formed therein for transmitting a spatial optical signal.

[0049] FIG. 11 is a side view of the internal configuration of a transmitting device according to the present disclosure. FIG. 11 shows a housing 210 cut along a cutting line passing through a window W. FIG. 11 is conceptual and does not accurately represent the shape of each component, the positional relationship between the components, the propagation of light, etc. The configuration of FIG. 11 may also be arranged upside down. FIG. 11 shows a top plate 211 that supports a light source 21 and a relay mirror 23. FIG. 11 also shows a bottom plate 212 on which a spatial light modulator 22 and annular mirror array 25 are arranged.

[0050] Fig. 12 is a conceptual diagram of the top plate of the transmitting device according to the present disclosure viewed from below. A through-hole T is opened in the center of the top plate 211. The through-hole T is an opening for allowing the illumination light 201 emitted from the light source 21 to pass downward. In the example of Fig. 12, the opening shape of the through-hole T is rectangular, but the opening shape of the through-hole T does not have to be rectangular. A relay mirror 23 is arranged on the underside of the top plate 211. The relay mirror 23 is a disk-shaped flat mirror.

[0051] FIG. 13 is a conceptual diagram of the bottom plate of a transmitting device according to the present disclosure, viewed from above. A spatial light modulator 22 and an annular mirror array 25 are arranged on the upper surface of the bottom plate 212. The spatial light modulator 22 is arranged in the central portion of the upper surface of the bottom plate 212. The modulation section 220 of the spatial light modulator 22 faces the light source 21. The annular mirror array 25 is arranged so as to surround the periphery of the spatial light modulator 22. The annular mirror array 25 is a mirror array in which multiple concave mirrors are arranged in an annular shape. The multiple concave mirrors that make up the annular mirror array 25 are arranged in an annular shape centered on the optical axis of the illumination light 201 emitted from the light source 21. The reflective surfaces 250 of the multiple concave mirrors that make up the annular mirror array 25 are all oriented in different directions.

[0052] The light source 21 has the same configuration as the light source 11 of the first embodiment. The light source 21 emits illumination light 201. The emission surface of the light source 21 is directed toward the modulation unit 220 of the spatial light modulator 22 via a through-hole T in the top plate 211. The light source 21 may be disposed inside the through-hole T. The light source 21 may be disposed on the lower surface of the top plate 211 or between the top plate 211 and the spatial light modulator 22. In this case, the through-hole T does not need to be formed in the top plate 211. The illumination light 201 emitted from the light source 21 passes through the through-hole T and is irradiated onto the modulation unit 220 of the spatial light modulator 22.

[0053] The spatial light modulator 22 has the same configuration as the spatial light modulator 12 of the first embodiment. The spatial light modulator 22 is a phase modulation type spatial light modulator. The spatial light modulator 22 has a modulation section 220. A plurality of modulation areas are set in the modulation section 220. A pattern (also called a phase image) corresponding to an image displayed by the projection light 205 is set in each of the plurality of modulation areas under the control of the communication controller 29. Each of the plurality of modulation areas is irradiated with illumination light 201 derived from laser light emitted from an emitter associated with that modulation area. The illumination light 201 incident on each of the plurality of modulation areas set in the modulation section 220 is modulated according to the pattern (phase image) set in each of the plurality of modulation areas. The modulated light 202 modulated in each of the plurality of modulation areas travels toward the reflecting surface 230 of the relay mirror 23.

[0054] The relay mirror 23 is a plane mirror formed in a disk shape centered on the center point of the top plate 211. A through hole T is opened in the relay mirror 23. A reflecting surface 230 of the relay mirror 23 faces the upper surface of the bottom plate 212 disposed below. The reflecting surface 230 of the relay mirror 23 is irradiated with modulated light 202 modulated by the modulation section 220 of the spatial light modulator 22. The modulated light 202 irradiated to the reflecting surface 230 of the relay mirror 23 is reflected by the reflecting surface 250 thereof and travels towards the reflecting surface 250 of the annular mirror array 25.

[0055] The annular mirror array 25 has the same configuration as the annular mirror array 15 of the first embodiment. The annular mirror array 25 has a configuration in which multiple concave mirrors are arranged in a circular ring shape. The reflective surfaces 250 of the concave mirrors are formed by free-form surfaces. Arranging multiple concave mirrors in a ring shape allows a wider area to be covered with fewer mirrors than arranging multiple plane mirrors in a ring shape. The eight concave mirrors that make up the annular mirror array 25 are arranged in a ring shape with their reflective surfaces 250 facing diagonally downward. The number of concave mirrors that make up the annular mirror array 25 is not limited to eight.

[0056] The modulated light 202 irradiated onto the reflecting surface 250 of the annular mirror array 25 is reflected by the reflecting surface 250. The light reflected by the reflecting surface 250 (projected light 205) is projected as a spatial light signal. The reflecting surface 250 of the annular mirror array 25 is directed in a 360-degree direction in the horizontal plane. Therefore, by using the transmitting device 2, the projected light 205 can be projected in a 360-degree direction in the horizontal plane by controlling the pattern (phase image) set in the modulation section 220 of the spatial light modulator 22. The projected light 205 is projected in a direction along the horizontal plane. The propagation axis of the projected light 205 only needs to be along the horizontal plane, and does not need to be completely parallel to the horizontal plane.

[0057] The communication controller 29 has the same configuration as the communication controller 19 of the first embodiment. The communication controller 29 controls the light source 21 and the spatial light modulator 22. For example, the communication controller 29 is realized by a microcomputer including a processor and a memory. The communication controller 29 sets a phase image corresponding to the image to be projected in the modulation unit 220. The communication controller 29 sets the phase image corresponding to the image to be projected in the modulation region set in the modulation unit 220 of the spatial light modulator 22. The phase image of the image to be projected may be stored in advance in a storage unit (not shown). There are no particular limitations on the shape or size of the image to be projected.

[0058] The communication controller 29 controls the spatial light modulator 22 so as to change a parameter that determines the difference between the phase of the illumination light 201 irradiated onto the modulation unit 220 and the phase of the modulated light 202 reflected by the modulation unit 220. The method of driving the spatial light modulator 22 by the communication controller 29 is determined depending on the modulation method of the spatial light modulator 22. The communication controller 29 drives the light source 21 in a state where a phase image corresponding to an image to be displayed is set in the modulation unit 220 of the spatial light modulator 22. As a result, the illumination light 201 emitted from the light source 21 is irradiated onto the modulation unit 220 in a state where the phase image is set in the modulation unit 220. The illumination light 201 irradiated onto the modulation unit 220 is modulated in the modulation unit 220.

[0059] Furthermore, the communication controller 29 modulates the illumination light 201 emitted from the light source 21 for communication with a communication target (not shown). In communication, the communication controller 29 controls the timing at which the illumination light 201 is emitted from the light source 21, with a phase image for communication set in the modulation unit 220 of the spatial light modulator 22. The illumination light 201 is modulated by such control. The modulation pattern of the illumination light 201 in communication is set arbitrarily.

[0060] As described above, the transmitting device of this embodiment includes a light source, a spatial light modulator, a relay mirror, an annular mirror array, and a communication controller. The light source emits illumination light. The spatial light modulator has a modulation section that is irradiated with the illumination light emitted from the light source. The relay mirror is arranged in the optical path of the modulated light emitted from the modulation section of the spatial light modulator. The relay mirror has a planar reflective surface that relays and reflects the modulated light toward the annular mirror array. The annular mirror array is composed of a plurality of concave mirrors arranged in an annular shape centered on the optical axis of the illumination light. The annular mirror array is arranged in a position where the modulated light relayed and reflected by the reflective surface of the relay mirror is reflected toward the side as a spatial optical signal. The communication controller sets a phase image used for spatial optical communication in the modulation section of the spatial light modulator. The communication controller controls the light source so that illumination light is irradiated onto the modulation section to which the phase image is set.

[0061] The transmitting device of this embodiment reflects modulated light modulated by the modulation unit of the spatial light modulator via the reflective surface of the relay mirror toward the reflective surface of the concave mirror that constitutes the annular mirror array. The larger the concave mirror that constitutes the annular mirror array, the smaller the deviation in the irradiation position of the spatial light signal due to processing errors of the concave mirror. In other words, the larger the annular mirror array, the more accurate the irradiation position of the spatial light signal. The larger the annular mirror array, the greater the amount of projected light that forms a large angle between the modulated light and the perpendicular axis relative to the modulation unit of the spatial light modulator. The larger the angle between the modulated light and the perpendicular axis relative to the modulation unit of the spatial light modulator, the lower the transmission power. By locating the annular mirror array and the spatial light modulator at a distance, the angle between the modulated light and the perpendicular axis relative to the modulation unit of the spatial light modulator can be reduced. However, such a configuration increases the size of the device. According to the transmitting device of this embodiment, the distance between the annular mirror array and the spatial light modulator can be increased by reflecting the modulated light back and forth using the relay mirror. Furthermore, according to the transmitting device of this embodiment, the size of the device can be reduced by reflecting the modulated light back and forth using a relay mirror, and therefore, according to this aspect, the accuracy of the irradiation position of the spatial optical signal can be improved without increasing the size of the device.

[0062] (Third embodiment) Next, a transmitting device according to a third embodiment will be described with reference to the drawings. The transmitting device of this embodiment differs from the transmitting devices of the first and second embodiments in that it includes a plurality of relay mirrors that reflect back modulated light modulated by a modulation section of a spatial light modulator.

[0063] (composition) 14 to 16 are conceptual diagrams showing an example of the configuration of a transmitting device according to the present disclosure. The transmitting device 3 includes a light source 31, a spatial light modulator 32, a relay mirror 33, an annular relay mirror 34, an annular mirror array 35, and a communication controller 39. The light source 31, the spatial light modulator 32, the relay mirror 33, the annular relay mirror 34, and the annular mirror array 35 form a transmitter. The transmitter is housed in a housing 310 having a window W formed therein for transmitting a spatial optical signal.

[0064] FIG. 14 is a side view of the internal configuration of a transmitting device according to the present disclosure. FIG. 14 shows a housing 310 cut along a cutting line passing through a window W. FIG. 14 is conceptual and does not accurately represent the shape of each component, the positional relationship between the components, the propagation of light, etc. The configuration of FIG. 14 may also be arranged upside down. FIG. 14 also shows a top plate 311 that supports a light source 31, a relay mirror 33, and an annular mirror array 35. FIG. 14 also shows a bottom plate 312 on which a spatial light modulator 32 and annular relay mirror 34 are disposed.

[0065] FIG. 15 is a conceptual diagram of the top plate of a transmitting device according to the present disclosure, viewed from below. A through-hole T is formed in the center of the top plate 311. The through-hole T is an opening for allowing the illumination light 301 emitted from the light source 31 to pass downward. In the example of FIG. 15, the opening shape of the through-hole T is rectangular, but the opening shape of the through-hole T does not have to be rectangular. A relay mirror 33 and an annular mirror array 35 are arranged on the underside of the top plate 311. The relay mirror 33 is a disk-shaped flat mirror. The annular mirror array 35 is a mirror array in which multiple concave mirrors are arranged in an annular shape. The relay mirror 33 and the annular mirror array 35 are arranged concentrically. The multiple concave mirrors that make up the annular mirror array 35 are arranged in an annular shape centered on the optical axis of the illumination light 301 emitted from the light source 31. The reflective surfaces 350 of the multiple concave mirrors that make up the annular mirror array 35 all face in different directions.

[0066] 16 is a conceptual diagram of the bottom plate 312 viewed from above. The spatial light modulator 32 and the annular relay mirror 34 are arranged on the upper surface of the bottom plate 312. The spatial light modulator 32 is arranged in the central portion of the upper surface of the bottom plate 312. The annular relay mirror 34 is arranged so as to surround the periphery of the spatial light modulator 32. The annular relay mirror 34 is an annular plane mirror.

[0067] The light source 31 has the same configuration as the light source 11 of the first embodiment. The light source 31 emits illumination light 301. The emission surface of the light source 31 is directed toward the modulation unit 320 of the spatial light modulator 32 through a through-hole T in the top plate 311. The light source 31 may be disposed inside the through-hole T. The light source 31 may be disposed on the lower surface of the top plate 311 or between the top plate 311 and the spatial light modulator 32. In this case, the through-hole T does not need to be formed in the top plate 311. The illumination light 301 emitted from the light source 31 passes through the through-hole T and is irradiated onto the modulation unit 320 of the spatial light modulator 32.

[0068] The spatial light modulator 32 has the same configuration as the spatial light modulator 12 of the first embodiment. The spatial light modulator 32 is a phase modulation type spatial light modulator. The spatial light modulator 32 has a modulation section 320. A plurality of modulation areas are set in the modulation section 320. A pattern (also called a phase image) corresponding to an image displayed by the projection light 305 is set in each of the plurality of modulation areas under the control of the communication controller 39. Each of the plurality of modulation areas is irradiated with illumination light 301 derived from a laser beam emitted from an emitter associated with that modulation area. The illumination light 301 incident on each of the plurality of modulation areas set in the modulation section 320 is modulated according to the pattern (phase image) set in each of the plurality of modulation areas. The modulated light 302 modulated in each of the plurality of modulation areas travels toward a reflecting surface 330 of the relay mirror 33.

[0069] The relay mirror 33 is a plane mirror formed in a disk shape centered on the central point of the top plate 311. A reflecting surface 330 of the relay mirror 33 faces the upper surface of the bottom plate 312 placed below. The relay mirror 33 is arranged concentrically with the annular mirror array 35. The relay mirror 33 is arranged inside the annular mirror array 35. The reflecting surface 330 of the relay mirror 33 is irradiated with modulated light 302 modulated by the modulation section 320 of the spatial light modulator 32. The modulated light 302 irradiated to the reflecting surface 330 of the relay mirror 33 is reflected by the reflecting surface 330 and travels toward the reflecting surface 340 of the annular relay mirror 34.

[0070] The annular relay mirror 34 is a plane mirror formed in an annular shape centered on the central point of the bottom plate 312. A reflecting surface 340 of the annular relay mirror 34 faces the underside of the top plate 311 disposed above. The modulated light 302 reflected by the reflecting surface 330 of the relay mirror 33 is irradiated onto the reflecting surface 340 of the annular relay mirror 34. The modulated light 302 irradiated onto the reflecting surface 340 of the annular relay mirror 34 is reflected by the reflecting surface 340 and travels toward the reflecting surface 350 of the annular mirror array 35.

[0071] The annular mirror array 35 has the same configuration as the annular mirror array 15 of the first embodiment. The annular mirror array 35 has a configuration in which multiple concave mirrors are arranged in a circular ring shape. The reflective surfaces 350 of the concave mirrors are formed by free-form surfaces. Arranging multiple concave mirrors in a ring shape allows a wider area to be covered with fewer mirrors than arranging multiple plane mirrors in a ring shape. The eight concave mirrors that make up the annular mirror array 35 are arranged in a ring shape with their reflective surfaces 350 facing diagonally downward. The number of concave mirrors that make up the annular mirror array 35 is not limited to eight.

[0072] The modulated light 302 irradiated onto the reflecting surface 350 of the annular mirror array 35 is reflected by the reflecting surface 350. The light reflected by the reflecting surface 350 (projected light 305) is projected as a spatial light signal. The reflecting surface 350 of the annular mirror array 35 is directed in a 360-degree direction in the horizontal plane. Therefore, by using the transmitting device 3, the projected light 305 can be projected in a 360-degree direction in the horizontal plane by controlling the pattern (phase image) set in the modulation section 320 of the spatial light modulator 32. The projected light 305 is projected in a direction along the horizontal plane. The propagation axis of the projected light 305 only needs to be along the horizontal plane, and does not need to be completely parallel to the horizontal plane.

[0073] The communication controller 39 has the same configuration as the communication controller 19 of the first embodiment. The communication controller 39 controls the light source 31 and the spatial light modulator 32. For example, the communication controller 39 is realized by a microcomputer including a processor and a memory. The communication controller 39 sets a phase image corresponding to the image to be projected in the modulation unit 320. The communication controller 39 sets the phase image corresponding to the image to be projected in the modulation region set in the modulation unit 320 of the spatial light modulator 32. The phase image of the image to be projected may be stored in advance in a storage unit (not shown). There are no particular limitations on the shape or size of the image to be projected.

[0074] The communication controller 39 controls the spatial light modulator 32 so as to change a parameter that determines the difference between the phase of the illumination light 301 irradiated onto the modulation unit 320 and the phase of the modulated light 302 reflected by the modulation unit 320. The method of driving the spatial light modulator 32 by the communication controller 39 is determined depending on the modulation method of the spatial light modulator 32. The communication controller 39 drives the light source 31 in a state where a phase image corresponding to an image to be displayed is set in the modulation unit 320 of the spatial light modulator 32. As a result, the illumination light 301 emitted from the light source 31 is irradiated onto the modulation unit 320 in a state where the phase image is set in the modulation unit 320. The illumination light 301 irradiated onto the modulation unit 320 is modulated in the modulation unit 320.

[0075] Furthermore, the communication controller 39 modulates the illumination light 301 emitted from the light source 31 for communication with a communication target (not shown). In communication, the communication controller 39 controls the timing at which the illumination light 301 is emitted from the light source 31, with a phase image for communication set in the modulation unit 320 of the spatial light modulator 32. The illumination light 301 is modulated by such control. The modulation pattern of the illumination light 301 in communication is set arbitrarily.

[0076] As described above, the transmitting device of this embodiment includes a light source, a spatial light modulator, a relay mirror, an annular relay mirror, an annular mirror array, and a communication controller. The light source emits illumination light. The spatial light modulator has a modulation unit that is irradiated with the illumination light emitted from the light source. The relay mirror is arranged in the optical path of the modulated light emitted from the modulation unit of the spatial light modulator. The relay mirror is arranged in a position where it relays and reflects the modulated light toward the reflective surface of the annular mirror array. The relay mirror has a planar reflective surface that relays and reflects the modulated light toward the reflective surface of the annular mirror array. The annular relay mirror is arranged in the optical path of the modulated light reflected by the reflective surface of the relay mirror. The annular relay mirror has a planar reflective surface that relays and reflects the modulated light as a spatial optical signal toward the reflective surface of the annular mirror array. The annular mirror array is composed of a plurality of concave mirrors arranged in an annular shape centered on the optical axis of the illumination light. The annular mirror array is arranged in a position where it reflects the modulated light relayed and reflected by the reflective surface of the annular relay mirror toward the side. The communication controller sets a phase image to be used for spatial optical communication in a modulation section of the spatial light modulator, and controls the light source so that illumination light is irradiated onto the modulation section in which the phase image is set.

[0077] The transmitting device of this embodiment reflects modulated light modulated by the modulation unit of the spatial light modulator toward the reflection surfaces of the concave mirrors that make up the annular mirror array via the reflection surfaces of the relay mirror and the annular relay mirror. According to the transmitting device of this embodiment, by reflecting the modulated light back and forth by the relay mirror and the annular relay mirror, the angle between the modulated light and the perpendicular axis to the modulation unit of the spatial light modulator can be reduced even if the annular relay mirror is made larger than in the second embodiment. Therefore, according to this aspect, the irradiation position accuracy of the spatial optical signal can be improved compared to the second embodiment without increasing the size of the device.

[0078] (Fourth embodiment) Next, a transmitting device according to a fourth embodiment will be described with reference to the drawings. The transmitting device of this embodiment differs from the transmitting devices of the first to third embodiments in that it includes a relay mirror having a convex reflecting surface that reflects back the modulated light modulated by the modulation section of the spatial light modulator.

[0079] (composition) 17 to 19 are conceptual diagrams showing an example of the configuration of a transmitting device according to the present disclosure. The transmitting device 4 includes a light source 41, a spatial light modulator 42, a relay mirror 43, an annular mirror array 45, and a communication controller 49. The light source 41, the spatial light modulator 42, the relay mirror 43, and the annular mirror array 45 constitute a transmitter. The transmitter is housed inside a housing 410 having a window W formed therein for transmitting a spatial optical signal.

[0080] FIG. 17 is a side view of the internal configuration of a transmitting device according to the present disclosure. FIG. 17 shows a housing 410 cut along a cutting line passing through a window W. FIG. 17 is conceptual and does not accurately represent the shape of each component, the positional relationship between the components, the propagation of light, etc. The configuration of FIG. 17 may also be arranged upside down. FIG. 17 shows a top plate 411 that supports a light source 41 and a relay mirror 43. FIG. 17 also shows a bottom plate 412 on which a spatial light modulator 42 and annular mirror array 45 are arranged.

[0081] FIG. 18 is a conceptual diagram of the top plate of a transmitting device according to the present disclosure, viewed from below. A through-hole T is opened in the center of the top plate 411. The through-hole T is an opening for allowing illumination light 401 emitted from the light source 41 to pass downward. In the example of FIG. 18, the opening shape of the through-hole T is rectangular, but the opening shape of the through-hole T does not have to be rectangular. A relay mirror 43 is disposed on the underside of the top plate 411. The relay mirror 43 is a convex mirror having a convex reflecting surface 430. For example, the reflecting surface 430 has the shape of a portion of a spherical surface. For example, the reflecting surface 430 has the shape of a portion of a free-form surface.

[0082] FIG. 19 is a conceptual diagram of the bottom plate of a transmitting device according to the present disclosure, viewed from above. A spatial light modulator 42 and an annular mirror array 45 are arranged on the upper surface of the bottom plate 412. The spatial light modulator 42 is arranged in the central portion of the upper surface of the bottom plate 412. A modulation section 420 of the spatial light modulator 42 faces the light source 41. The annular mirror array 45 is arranged so as to surround the periphery of the spatial light modulator 42. The annular mirror array 45 is a mirror array in which multiple concave mirrors are arranged in an annular shape. The multiple concave mirrors that make up the annular mirror array 45 are arranged in an annular shape centered on the optical axis of the illumination light 401 emitted from the light source 41. The reflective surfaces 450 of the multiple concave mirrors that make up the annular mirror array 45 are all oriented in different directions.

[0083] The light source 41 has the same configuration as the light source 11 of the first embodiment. The light source 41 emits illumination light 401. The emission surface of the light source 41 is directed toward the modulation unit 420 of the spatial light modulator 42 through a through-hole T in the top plate 411. The light source 41 may be disposed inside the through-hole T. The light source 41 may be disposed on the lower surface of the top plate 411 or between the top plate 411 and the spatial light modulator 42. In this case, the through-hole T does not need to be formed in the top plate 411. The illumination light 401 emitted from the light source 41 passes through the through-hole T and is irradiated onto the modulation unit 420 of the spatial light modulator 42.

[0084] The spatial light modulator 42 has the same configuration as the spatial light modulator 12 of the first embodiment. The spatial light modulator 42 is a phase modulation type spatial light modulator. The spatial light modulator 42 has a modulation section 420. A plurality of modulation areas are set in the modulation section 420. A pattern (also called a phase image) corresponding to an image displayed by the projection light 405 is set in each of the plurality of modulation areas under the control of the communication controller 49. Each of the plurality of modulation areas is irradiated with illumination light 401 derived from laser light emitted from an emitter associated with that modulation area. The illumination light 401 incident on each of the plurality of modulation areas set in the modulation section 420 is modulated according to the pattern (phase image) set in each of the plurality of modulation areas. The modulated light 402 modulated in each of the plurality of modulation areas travels toward the reflecting surface 430 of the relay mirror 43.

[0085] The relay mirror 43 is a convex mirror formed in a disk shape centered on the center point of the top plate 411. A through hole T is opened in the relay mirror 43. A reflecting surface 430 of the relay mirror 43 faces the upper surface of the bottom plate 412 disposed below. The reflecting surface 430 of the relay mirror 43 is irradiated with modulated light 402 modulated by the modulation section 420 of the spatial light modulator 42. The modulated light 402 irradiated to the reflecting surface 430 of the relay mirror 43 is reflected by the reflecting surface 450 thereof and travels towards the reflecting surface 450 of the annular mirror array 45.

[0086] The annular mirror array 45 has the same configuration as the annular mirror array 15 of the first embodiment. The annular mirror array 45 has a configuration in which multiple concave mirrors are arranged in a circular ring shape. The reflective surfaces 450 of the concave mirrors are formed by free-form surfaces. Arranging multiple concave mirrors in a ring shape allows a wider area to be covered with fewer mirrors than arranging multiple plane mirrors in a ring shape. The eight concave mirrors that make up the annular mirror array 45 are arranged in a ring shape with their reflective surfaces 450 facing diagonally downward. The number of concave mirrors that make up the annular mirror array 45 is not limited to eight.

[0087] The modulated light 402 irradiated onto the reflecting surface 450 of the annular mirror array 45 is reflected by the reflecting surface 450. The light reflected by the reflecting surface 450 (projected light 405) is projected as a spatial light signal. The reflecting surface 450 of the annular mirror array 45 is directed in a 360-degree direction in the horizontal plane. Therefore, by using the transmitting device 4, the projected light 405 can be projected in a 360-degree direction in the horizontal plane by controlling the pattern (phase image) set in the modulation section 420 of the spatial light modulator 42. The projected light 405 is projected in a direction along the horizontal plane. The propagation axis of the projected light 405 only needs to be along the horizontal plane, and does not need to be completely parallel to the horizontal plane.

[0088] The communication controller 49 has the same configuration as the communication controller 19 of the first embodiment. The communication controller 49 controls the light source 41 and the spatial light modulator 42. For example, the communication controller 49 is realized by a microcomputer including a processor and a memory. The communication controller 49 sets a phase image corresponding to the image to be projected in the modulation unit 420. The communication controller 49 sets the phase image corresponding to the image to be projected in the modulation region set in the modulation unit 420 of the spatial light modulator 42. The phase image of the image to be projected may be stored in advance in a storage unit (not shown). There are no particular limitations on the shape or size of the image to be projected.

[0089] The communication controller 49 controls the spatial light modulator 42 so as to change a parameter that determines the difference between the phase of the illumination light 401 irradiated onto the modulation unit 420 and the phase of the modulated light 402 reflected by the modulation unit 420. The method of driving the spatial light modulator 42 by the communication controller 49 is determined depending on the modulation method of the spatial light modulator 42. The communication controller 49 drives the light source 41 in a state where a phase image corresponding to an image to be displayed is set in the modulation unit 420 of the spatial light modulator 42. As a result, the illumination light 401 emitted from the light source 41 is irradiated onto the modulation unit 420 in a state where the phase image is set in the modulation unit 420. The illumination light 401 irradiated onto the modulation unit 420 is modulated in the modulation unit 420.

[0090] Furthermore, the communication controller 49 modulates the illumination light 401 emitted from the light source 41 for communication with a communication target (not shown). In communication, the communication controller 49 controls the timing at which the illumination light 401 is emitted from the light source 41, with a phase image for communication set in the modulation unit 420 of the spatial light modulator 42. The illumination light 401 is modulated by such control. The modulation pattern of the illumination light 401 in communication is set arbitrarily.

[0091] As described above, the transmitting device of this embodiment includes a light source, a spatial light modulator, a relay mirror, an annular mirror array, and a communication controller. The light source emits illumination light. The spatial light modulator has a modulation section that is irradiated with the illumination light emitted from the light source. The relay mirror is arranged in the optical path of the modulated light emitted from the modulation section of the spatial light modulator. The relay mirror has a convex reflective surface that relays and reflects the modulated light toward the annular mirror array. The annular mirror array is composed of multiple concave mirrors arranged in an annular shape centered on the optical axis of the illumination light. The annular mirror array is arranged in a position where the modulated light relayed and reflected by the reflective surface of the relay mirror is reflected toward the side as a spatial optical signal. The communication controller sets a phase image used for spatial optical communication in the modulation section of the spatial light modulator. The communication controller controls the light source so that illumination light is irradiated onto the modulation section to which the phase image is set.

[0092] The transmitting device of this embodiment reflects modulated light modulated by the modulation section of the spatial light modulator via the reflection surface of a relay mirror having a convex reflection surface toward the reflection surface of a concave mirror that constitutes the annular mirror array. According to the transmitting device of this embodiment, the reflection surface of the concave mirror that constitutes the annular mirror array can be increased by widening the reflection angle using the relay mirror having a convex reflection surface. According to the transmitting device of this embodiment, the modulated light is reflected back and forth by the relay mirror having a convex reflection surface. As in the third embodiment, even if the annular relay mirror is enlarged, the angle between the modulated light and the perpendicular axis to the modulation section of the spatial light modulator can be reduced. Furthermore, according to the transmitting device of this embodiment, the same effect as in the third embodiment can be achieved with a single relay mirror. Therefore, according to this aspect, the device can be simplified more than in the third embodiment.

[0093] (Fifth embodiment) Next, a communication device according to a fifth embodiment will be described with reference to the drawings. The communication device of this embodiment is configured by combining a transmitting device and a receiving device. The transmitting device has the configuration of any one of the first to fourth embodiments. The receiving device is not particularly limited as long as it is configured to receive a spatial optical signal. In the following, an example of a receiving device having a light receiving function including a ball lens will be given. Note that the communication device of this embodiment may also have a receiving device having a light receiving function other than a light receiving function including a ball lens.

[0094] 20 is a conceptual diagram showing an example of the configuration of a communication device according to the present disclosure. The communication device 500 includes a transmitting device 50, a receiving device 57, and a communication control device 59. The communication device 500 transmits and receives spatial optical signals to and from external communication targets. For this reason, the communication device 500 is provided with an opening or window for transmitting and receiving spatial optical signals.

[0095] The transmitting device 50 is any one of the transmitting devices according to the first to fourth embodiments. The transmitting device 50 receives a control signal from a communication control device 59. The transmitting device 50 projects a spatial optical signal according to the control signal. The spatial optical signal projected from the transmitting device 50 is received by a communication target (not shown) to which the spatial optical signal is to be transmitted.

[0096] The receiving device 57 receives a spatial optical signal transmitted from a communication target (not shown). The receiving device 57 converts the received spatial optical signal into an electrical signal. The receiving device 57 outputs the converted electrical signal to the communication control device 59. For example, the receiving device 57 has a light receiving function including a ball lens. Alternatively, the receiving device 57 may have a light receiving function that does not include a ball lens.

[0097] The communication control device 59 acquires the signal output from the receiving device 57. The communication control device 59 executes processing according to the acquired signal. There are no particular limitations on the processing executed by the communication control device 59. The communication control device 59 outputs a control signal to the transmitting device 50 for transmitting an optical signal according to the processing executed. For example, the communication control device 59 executes processing based on predetermined conditions according to information included in the signal received by the receiving device 57. For example, the communication control device 59 executes processing specified by an administrator of the communication device 500 according to information included in the signal received by the receiving device 57.

[0098] [Receiver] Next, the configuration of the receiving device 57 will be described with reference to the drawings. FIG. 21 is a conceptual diagram for explaining an example of the configuration of a receiver provided in a communication device according to the present disclosure. The receiving device 57 includes a ball lens 571, a light receiving element 573, and a receiving circuit 575. FIG. 21 is a side view of the internal configuration of the receiving device 57 as seen from a lateral perspective. There are no particular limitations on the position of the receiving circuit 575. The receiving circuit 575 may be disposed inside or outside the receiving device 57. The function of the receiving circuit 575 may also be included in the communication control device 59.

[0099] Ball lens 571 is a spherical lens. Ball lens 571 is an optical element that focuses a spatial optical signal transmitted from a communication target. Ball lens 571 is spherical when viewed from any angle. A portion of ball lens 571 protrudes from an opening formed in the housing of receiving device 57. Ball lens 571 focuses the incident spatial optical signal. The incident spatial optical signal is focused on ball lens 571 that protrudes from the opening. As long as the spatial optical signal can be focused, a portion of ball lens 571 does not need to protrude from the opening.

[0100] Light (optical signal) derived from the spatial optical signal focused by ball lens 571 is focused toward the focusing region of ball lens 571. Because ball lens 571 is spherical, it focuses spatial optical signals arriving from any direction. That is, ball lens 571 exhibits similar focusing performance for spatial optical signals arriving from any direction. Light incident on ball lens 571 is refracted when entering ball lens 571. Furthermore, light traveling inside ball lens 571 is refracted again when emitting to the outside of ball lens 571. Most of the light emitted from ball lens 571 is focused in the focusing region.

[0101] For example, ball lens 571 can be made of materials such as glass, crystal, and resin. When receiving a spatial optical signal in the visible range, ball lens 571 can be made of materials such as glass, crystal, and resin that transmit / refract light in the visible range. For example, ball lens 571 can be made of optical glass such as crown glass and flint glass. For example, ball lens 571 can be made of crown glass such as BK (Boron Kron). For example, ball lens 571 can be made of flint glass such as LaSF (Lanthanum Schwerflint). For example, quartz glass can be used for ball lens 571. For example, crystal such as sapphire can be used for ball lens 571. For example, transparent resin such as acrylic can be used for ball lens 571.

[0102] When the spatial optical signal is light in the near-infrared region (hereinafter, near-infrared), a material that transmits near-infrared light is used for the ball lens 571. For example, when receiving a spatial optical signal in the near-infrared region of about 1.5 micrometers (μm), materials such as silicon can be used for the ball lens 571 in addition to glass, crystal, resin, etc. When the spatial optical signal is light in the infrared region (hereinafter, infrared), a material that transmits infrared light can be used for the ball lens 571. For example, when the spatial optical signal is infrared, silicon, germanium, or a chalcogenide-based material can be used for the ball lens 571. There are no limitations on the material of the ball lens 571 as long as it can transmit / refract light in the wavelength region of the spatial optical signal. The material of the ball lens 571 may be selected appropriately depending on the desired refractive index and application.

[0103] Ball lens 571 may be replaced by another light collector as long as it can collect the spatial optical signal toward the region where light receiving element 573 is arranged. For example, ball lens 571 may be a light beam control element that guides the incident spatial optical signal toward the light receiving portion of light receiving element 573. For example, ball lens 571 may be configured by combining lenses and light beam control elements. For example, a configuration that guides the optical signal collected by ball lens 571 toward the light receiving portion of light receiving element 573 may be added.

[0104] Light receiving element 573 is arranged after ball lens 571. Light receiving element 573 is arranged in the light collecting region of ball lens 571. Light receiving element 573 has a light receiving portion that receives an optical signal collected by ball lens 571. The optical signal collected by ball lens 571 is received by the light receiving portion of light receiving element 573. Light receiving element 573 converts the received optical signal into an electrical signal (hereinafter, signal). Light receiving element 573 outputs the converted signal to receiving circuit 575. FIG. 25 shows an example in which a single light receiving element 573 is used. For example, multiple light receiving elements 573 may be arranged in the light collecting region of ball lens 571. For example, a light receiving element array in which multiple light receiving elements 573 are arrayed may be arranged in the light collecting region of ball lens 571.

[0105] The light receiving element 573 receives light in the wavelength region of the spatial optical signal to be received. For example, the light receiving element 573 is sensitive to light in the visible region. For example, the light receiving element 573 is sensitive to light in the infrared region. The light receiving element 573 is sensitive to light with a wavelength in the 1.5 μm (micrometer) band, for example. Note that the wavelength band of light to which the light receiving element 573 is sensitive is not limited to the 1.5 μm band. The wavelength band of light received by the light receiving element 573 can be set arbitrarily to match the wavelength of the spatial optical signal to be received. The wavelength band of light received by the light receiving element 573 may be set to, for example, the 0.8 μm band, the 1.55 μm band, or the 2.2 μm band. The wavelength band of light received by the light receiving element 573 may also be, for example, the 0.8 to 1 μm band. A shorter wavelength band is advantageous for optical space communication during rainfall because it is less absorbed by moisture in the atmosphere. Furthermore, if the light receiving element 573 becomes saturated with intense sunlight, it will be unable to read the optical signal derived from the spatial optical signal. Therefore, a color filter that selectively passes light in the wavelength band of the spatial optical signal may be installed before the light receiving element 573.

[0106] For example, the light receiving element 573 can be realized by an element such as a photodiode or a phototransistor. For example, the light receiving element 573 can be realized by an avalanche photodiode. The light receiving element 573 realized by an avalanche photodiode can support high-speed communication. Note that the light receiving element 573 may be realized by an element other than a photodiode, a phototransistor, or an avalanche photodiode as long as it can convert an optical signal into an electrical signal. To improve the communication speed, it is preferable that the light receiving portion of the light receiving element 573 be as small as possible. For example, the light receiving portion of the light receiving element 573 has a square light receiving surface with one side measuring approximately 5 mm (millimeters). For example, the light receiving portion of the light receiving element 573 has a circular light receiving surface with a diameter of approximately 0.1 to 0.3 mm. The size and shape of the light receiving portion of the light receiving element 573 may be selected depending on the wavelength band of the spatial optical signal, the communication speed, etc.

[0107] For example, a polarizing filter (not shown) may be arranged in front of the light receiving element 573. The polarizing filter is arranged corresponding to the light receiving portion of the light receiving element 573. For example, the polarizing filter is arranged overlapping the light receiving portion of the light receiving element 573. For example, the polarizing filter may be selected depending on the polarization state of the spatial optical signal to be received. For example, if the spatial optical signal to be received is linearly polarized, the polarizing filter includes a half-wave plate. For example, if the spatial optical signal to be received is circularly polarized, the polarizing filter includes a quarter-wave plate. The polarization state of the optical signal that passes through the polarizing filter is converted depending on the polarization characteristics of the polarizing filter.

[0108] The receiving circuit 575 acquires the signal output from the light receiving element 573. The receiving circuit 575 amplifies the signal from the light receiving element 573. The receiving circuit 575 decodes the amplified signal. The signal decoded by the receiving circuit 575 is used for any purpose. There are no particular limitations on the use of the signal decoded by the receiving circuit 575.

[0109] [Communication Device] Fig. 22 is a conceptual diagram showing an example of the configuration of a communication device according to the present disclosure. The communication device 501 includes a transmitting device 510, a receiving device 570, and a communication control device (not shown). The receiving circuit and the communication control device are omitted from Fig. 22. The receiving circuit and the communication control device are disposed inside the communication device 501. The communication device 501 has a configuration combining the transmitting device 510 and the receiving device 570, both of which have cylindrical outer shapes.

[0110] Receiving device 570 includes ball lens 571, photodetector 572, window 576, top plate 577, and bottom plate 578. Ball lens 571 is sandwiched between top plate 577 and bottom plate 578. Because the top and bottom of ball lens 571 are not used for transmitting and receiving spatial optical signals, they may be processed to be flat so that they can be easily sandwiched between top plate 577 and bottom plate 578. Photodetector 572 is arranged in accordance with the light-condensing region of ball lens 571 so as to receive the spatial optical signal to be received. Photodetector 572 has a photodetector array in which multiple photodetectors are arranged in an annular shape. The multiple photodetectors are arranged in the light-condensing region of ball lens 571. The multiple photodetectors are arranged with their light-receiving portions facing ball lens 571. The multiple photodetectors are connected to the communication control device and transmitting device 510 by conductors 579.

[0111] A window 576 is arranged on the side of the cylindrical receiving device 570. The window 576 is made of a material that transmits the spatial optical signal used for communication. The window 576 functions as a filter that removes unnecessary light and selectively transmits the spatial optical signal used for communication. A top plate 577 is arranged on the upper surface of the cylindrical receiving device 570. A bottom plate 578 is arranged on the lower surface of the cylindrical receiving device 570. The top plate 577 and the bottom plate 578 sandwich the top and bottom of a ball lens 571. A ring-shaped optical receiver 572 is arranged around the ball lens 571. The optical receiver 572 includes multiple light-receiving elements with their light-receiving portions facing the ball lens 571. The spatial optical signal incident on the ball lens 571 through the window 576 is focused by the ball lens 571 toward the optical receiver 572. The optical signal focused on the optical receiver 572 is guided toward the light-receiving portion of one of the light-receiving elements. The optical signal that reaches the light receiving portion of the light receiving element is received by the light receiving element. A communication control device (not shown) decodes the optical signal received by the light receiving element included in the light receiver 572. The communication control device causes the transmitting device 510 to transmit a spatial optical signal in response to the decoded optical signal.

[0112] The transmitting device 510 is any one of the transmitting devices according to the first to fourth embodiments. The transmitting device 510 is housed inside a cylindrical housing. The cylindrical housing has a slit formed therein that is opened in accordance with the transmission direction of the spatial optical signal from the transmitting device 510. For example, if the transmitting device 510 can transmit the spatial optical signal in a 360-degree azimuth, a slit is formed on the side surface of the housing of the transmitting device 510 in accordance with the transmission direction of the spatial optical signal.

[0113] [Application example] Next, application examples of this embodiment will be described with reference to the drawings. In the following application example, a plurality of communication devices 501 transmit and receive spatial optical signals. FIG. 23 is a conceptual diagram for explaining an application example in the present disclosure. In this application example, an example (communication system) of a communication network in which a plurality of communication devices 501 are arranged on top of poles (pole-mounted spaces) such as utility poles and streetlights arranged in town is given.

[0114] There are few obstacles in the space above a pole. Therefore, the space above a pole is suitable for installing the communication device 501. Furthermore, if the communication device 501 is installed at a similar height, the direction of arrival of the spatial optical signal is limited to the horizontal direction. Therefore, the light receiving area of ​​the optical receiver constituting the receiving device 570 can be reduced, and the device can be simplified. A pair of communication devices 501 that transmit and receive spatial optical signals to each other is arranged so that at least one communication device 501 receives the spatial optical signal transmitted from the other communication device 501. A pair of communication devices 501 may be arranged so that they transmit and receive spatial optical signals to each other. When a communication network for spatial optical signals is configured with multiple communication devices 501, a communication device 501 located in the middle may be arranged to relay a spatial optical signal transmitted from another communication device 501 to another communication device 501.

[0115] According to this application example, communication using spatial optical signals becomes possible among a plurality of communication devices 501 arranged in the space above a pole. For example, in response to communication between the communication devices 501, wireless communication may be performed between the communication device 501 and a wireless device or base station installed in a car, a house, or the like. For example, the communication device 501 may be connected to the Internet via a communication cable or the like installed on a pole.

[0116] As described above, the communication device of this embodiment includes a receiving device, a transmitting device, and a communication control device. The transmitting device is any one of the transmitting devices according to the first to fourth embodiments. The receiving device receives a spatial optical signal transmitted from a communication target. The communication control device acquires a signal based on the spatial optical signal transmitted from the communication target and received by the receiving device. The communication control device executes processing according to the acquired signal. The communication control device causes the transmitting device to transmit a spatial optical signal according to the executed processing toward the communication target.

[0117] The transmitting device included in the communication device of this embodiment transmits a spatial optical signal that is less likely to attenuate in any direction along a horizontal plane. Therefore, the transmitting device of this embodiment can transmit a spatial optical signal with stable intensity to multiple communication devices arranged in any direction along a horizontal plane. In other words, according to this embodiment, it is possible to continuously transmit a spatial optical signal for optical space communication to communication devices arranged in any direction along a horizontal plane.

[0118] A communication system according to one aspect of the present embodiment includes a plurality of the above-described communication devices. In the communication system, the plurality of communication devices are arranged in positions where they can transmit and receive spatial optical signals to and from each other. According to this aspect, a communication network capable of realizing continuous transmission and reception of spatial optical signals can be realized.

[0119] (Sixth embodiment) Next, a transmitting device in a sixth embodiment will be described with reference to the drawings. The transmitting device in this embodiment has a simplified configuration of the transmitting devices in the first to fourth embodiments. For example, the functions of the components included in the transmitting device in this embodiment are realized by the functions of the components included in the transmitting devices in the first to fourth embodiments. The transmitting device in this embodiment is controlled by the communication controller in the first to fourth embodiments. A description of the control method by the communication controller will be omitted.

[0120] 24 is a conceptual diagram showing an example of the configuration of a transmission device according to the present disclosure. The transmission device 6 includes a light source 61, a spatial light modulator 62, and an annular mirror array 65.

[0121] The light source 61 emits illumination light 601. The spatial light modulator 62 has a modulation section 620 onto which the illumination light 601 emitted from the light source is irradiated. The annular mirror array 65 is composed of a plurality of concave mirrors arranged in an annular shape centered on the optical axis of the illumination light 601. The annular mirror array 65 is positioned so as to reflect modulated light 602 modulated by the modulation section 620 of the spatial light modulator 62 laterally as projected light 605.

[0122] The transmitting device of this embodiment includes an annular mirror array composed of multiple concave mirrors. The annular mirror array is composed of concave mirrors with reflective surfaces having a larger radius of curvature than an annular mirror composed of a single reflective surface, and therefore can suppress the spread of the projection angle in the horizontal plane. Furthermore, the annular mirror array is composed of concave mirrors with reflective surfaces having a larger radius of curvature than an annular mirror array composed of multiple plane mirrors, and therefore can suppress the spread of the projection angle compared to an annular mirror array composed of multiple plane mirrors. In other words, the transmitting device of this embodiment can transmit a spatial optical signal that is less likely to be attenuated in any direction along the horizontal plane.

[0123] (Hardware) Next, a hardware configuration for executing control and processing according to each embodiment of the present disclosure will be described with reference to the drawings. Here, an information processing device 90 (computer) shown in FIG. 25 is given as an example of such a hardware configuration. The information processing device 90 in FIG. 25 is an example of a configuration for executing control and processing according to each embodiment, and does not limit the scope of the present disclosure.

[0124] As shown in Fig. 25, an information processing device 90 includes a processor 91, a main storage device 92, an auxiliary storage device 93, an input / output interface 95, and a communication interface 96. In Fig. 25, interface is abbreviated as I / F (Interface). The processor 91, the main storage device 92, the auxiliary storage device 93, the input / output interface 95, and the communication interface 96 are connected to each other via a bus 98 so as to be able to communicate data with each other. The processor 91, the main storage device 92, the auxiliary storage device 93, and the input / output interface 95 are also connected to a network such as the Internet or an intranet via the communication interface 96.

[0125] The processor 91 loads a program (instructions) stored in an auxiliary storage device 93 or the like onto the main storage device 92. For example, the program is a software program for executing the control and processing of each embodiment. The processor 91 executes the program loaded onto the main storage device 92. The processor 91 executes the program to execute the control and processing of each embodiment.

[0126] The main memory device 92 has an area in which a program is loaded. The processor 91 loads a program stored in the auxiliary memory device 93 or the like into the main memory device 92. The main memory device 92 is realized by a volatile memory such as a DRAM (Dynamic Random Access Memory). Alternatively, a non-volatile memory such as an MRAM (Magneto-resistive Random Access Memory) may be configured / added to the main memory device 92.

[0127] The auxiliary storage device 93 stores various data such as programs. The auxiliary storage device 93 is realized by a local disk such as a hard disk or flash memory. Note that it is also possible to configure the main storage device 92 to store various data, thereby omitting the auxiliary storage device 93.

[0128] The input / output interface 95 is an interface for connecting the information processing device 90 to peripheral devices based on standards and specifications. The communication interface 96 is an interface for connecting to external systems and devices via a network such as the Internet or an intranet based on standards and specifications. The input / output interface 95 and the communication interface 96 may be a common interface for connecting to external devices.

[0129] Input devices such as a keyboard, mouse, and touch panel may be connected to the information processing device 90 as needed. These input devices are used to input information and settings. When a touch panel is used as the input device, a screen having the function of the touch panel serves as the interface. The processor 91 and the input devices are connected via an input / output interface 95.

[0130] The information processing device 90 may be equipped with a display device for displaying information. When a display device is equipped, the information processing device 90 is equipped with a display control device (not shown) for controlling the display of the display device. The information processing device 90 and the display device are connected via an input / output interface 95.

[0131] The information processing device 90 may be equipped with a drive device. The drive device acts as an intermediary between the processor 91 and a recording medium (program recording medium) to read data and programs stored on the recording medium and to write processing results of the information processing device 90 to the recording medium. The information processing device 90 and the drive device are connected via an input / output interface 95.

[0132] The above is an example of a hardware configuration for enabling control and processing according to each embodiment of the present disclosure. The hardware configuration of Fig. 25 is an example of a hardware configuration for executing control and processing according to each embodiment, and does not limit the scope of the present disclosure. A program that causes a computer to execute control and processing according to each embodiment is also included in the scope of the present disclosure.

[0133] A program recording medium on which a program according to each embodiment is recorded is also included within the scope of the present disclosure. The recording medium can be realized, for example, as an optical recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc). The recording medium may also be realized as a semiconductor recording medium such as a USB (Universal Serial Bus) memory or an SD (Secure Digital) card. The recording medium may also be realized as a magnetic recording medium such as a flexible disk or other recording medium. When a program executed by a processor is recorded on a recording medium, the recording medium corresponds to a program recording medium.

[0134] The components of each embodiment may be combined in any manner, may be realized by software, or may be realized by a circuit.

[0135] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

[0136] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) a light source that emits illumination light; a spatial light modulator having a modulation unit onto which the illumination light emitted from the light source is irradiated; a transmitting device comprising: an annular mirror array composed of a plurality of concave mirrors arranged in an annular shape centered on the optical axis of the illumination light, and positioned so as to reflect modulated light modulated by the modulation section of the spatial light modulator toward the side as a spatial light signal. (Appendix 2) a relay mirror disposed in an optical path of the modulated light emitted from the modulation unit of the spatial light modulator, the relay mirror having a flat reflecting surface that relays and reflects the modulated light toward the annular mirror array; The annular mirror array 2. The transmitting device according to claim 1, which is arranged in a position where the modulated light relayed and reflected by the reflecting surface of the relay mirror is reflected laterally. (Appendix 3) an annular relay mirror having a flat reflecting surface that is disposed in an optical path of the modulated light reflected by the reflecting surface of the relay mirror and that relays and reflects the modulated light toward the annular mirror array; The annular mirror array The transmitting device according to claim 2, which is arranged in a position where the modulated light relayed and reflected by the reflecting surface of the annular relay mirror is reflected toward the side. (Appendix 4) a relay mirror disposed in an optical path of the modulated light emitted from the modulation unit of the spatial light modulator, the relay mirror having a convex reflecting surface that relays and reflects the modulated light toward a reflecting surface of the annular mirror array; The annular mirror array 2. The transmitting device according to claim 1, which is arranged in a position where the modulated light relayed and reflected by the reflecting surface of the relay mirror is reflected laterally. (Appendix 5) 2. The transmitting device according to claim 1, further comprising a communication controller that sets a phase image used for spatial light communication in the modulation section of the spatial light modulator and controls the light source so that the illumination light is irradiated onto the modulation section on which the phase image is set. (Appendix 6) the light source has a plurality of emitters; The communication controller a plurality of modulation regions are set in the modulation section of the spatial light modulator in association with the plurality of emitters; A transmitting device as described in Appendix 5, in which, in a mode for searching for a communication target, a phase image in which the modulated light modulated in the plurality of modulation regions is irradiated onto a single concave mirror among the plurality of concave mirrors constituting the annular mirror array is set in the modulation section of the spatial light modulator. (Appendix 7) The communication controller A transmitting device as described in Appendix 6, in which, in a mode of communicating with the communication target, each of the multiple concave mirrors constituting the annular mirror array is associated with one of the multiple communication targets, and a phase image in which the modulated light modulated in one of the multiple modulation areas is irradiated onto each of the concave mirrors associated with one of the multiple communication targets is set in the modulation section of the spatial light modulator. (Appendix 8) The communication controller A transmitting device as described in Appendix 6, in which, in a mode of communicating with the communication target, at least one of the multiple concave mirrors constituting the annular mirror array is associated with a single communication target, and a phase image in which the modulated light modulated in the multiple modulation regions is irradiated onto the concave mirror associated with the single communication target is set in the modulation section of the spatial light modulator. (Appendix 9) a photodetector disposed on either side of the plurality of concave mirrors constituting the annular mirror array; The communication controller In an optical power measurement mode, a phase image is set in the spatial light modulator so that the modulated light modulated by the modulation unit of the spatial light modulator is irradiated toward the photodetector; measuring the optical power of the modulated light detected by the photodetector; 6. The transmitting device according to claim 5, wherein the output of the light source is adjusted in accordance with the measured optical power of the modulated light. (Appendix 10) A transmitting device according to any one of Supplementary Notes 1 to 9; a receiving device for receiving a spatial optical signal transmitted from a communication target; a communication control device that acquires a signal based on the spatial optical signal transmitted from the communication target and received by the receiving device, performs processing according to the acquired signal, and causes the transmitting device to transmit a spatial optical signal according to the performed processing toward the communication target. [Explanation of symbols]

[0137] 1, 2, 3, 4, 6 Transmitting device 11, 21, 31, 41, 61 light source 12, 22, 32, 42, 62 spatial light modulator 14 Photodetector 15, 25, 35, 45, 65 Annular Mirror Array 19, 29, 39, 49 Communication controller 23, 33, 43 relay mirror 34 Circular relay mirror 50, 510 Transmitting device 57, 570 Receiver 59 Communication control device 110, 210, 310, 410 enclosure 111, 211, 311, 411 top plate 112, 212, 312, 412 bottom plate 500, 501 Communication equipment 571 Ball Lens 572 Photoreceiver 573 Photodetector 575 receiving circuit 576 Windows 577 Top Plate 578 Bottom plate 579 Conductor

Claims

1. a light source that emits illumination light; a spatial light modulator having a modulation unit onto which the illumination light emitted from the light source is irradiated; a transmitting device comprising: an annular mirror array composed of a plurality of concave mirrors arranged in an annular shape centered on the optical axis of the illumination light, and positioned so as to reflect modulated light modulated by the modulation section of the spatial light modulator toward the side as a spatial light signal.

2. a relay mirror disposed in an optical path of the modulated light emitted from the modulation unit of the spatial light modulator, the relay mirror having a flat reflecting surface that relays and reflects the modulated light toward the annular mirror array; The annular mirror array 2. The transmitting device according to claim 1, wherein the transmitting device is disposed at a position where the modulated light relayed and reflected by the reflecting surface of the relay mirror is reflected laterally.

3. an annular relay mirror having a flat reflecting surface that is disposed in an optical path of the modulated light reflected by the reflecting surface of the relay mirror and that relays and reflects the modulated light toward the annular mirror array; The annular mirror array 3. The transmitting device according to claim 2, wherein the transmitting device is disposed at a position where the modulated light relayed and reflected by the reflecting surface of the annular relay mirror is reflected laterally.

4. a relay mirror disposed in an optical path of the modulated light emitted from the modulation unit of the spatial light modulator, the relay mirror having a convex reflecting surface that relays and reflects the modulated light toward a reflecting surface of the annular mirror array; The annular mirror array 2. The transmitting device according to claim 1, wherein the transmitting device is disposed at a position where the modulated light relayed and reflected by the reflecting surface of the relay mirror is reflected laterally.

5. 2. The transmitting device according to claim 1, further comprising a communication controller that sets a phase image used in spatial light communication in the modulation section of the spatial light modulator and controls the light source so that the illumination light is irradiated onto the modulation section on which the phase image is set.

6. the light source has a plurality of emitters; The communication controller a plurality of modulation regions are set in the modulation section of the spatial light modulator in association with the plurality of emitters; 6. The transmitting device according to claim 5, wherein in a mode for searching for a communication target, a phase image in which the modulated light modulated in the plurality of modulation regions is irradiated onto a single concave mirror among the plurality of concave mirrors constituting the annular mirror array is set in the modulation section of the spatial light modulator.

7. The communication controller 7. The transmitting device according to claim 6, wherein in a mode of communicating with the communication target, each of the plurality of concave mirrors constituting the annular mirror array is associated with one of the plurality of communication targets, and a phase image in which the modulated light modulated in one of the plurality of modulation regions is irradiated onto each of the concave mirrors associated with one of the plurality of communication targets is set in the modulation section of the spatial light modulator.

8. The communication controller 7. The transmitting device according to claim 6, wherein in a mode of communicating with the communication target, at least one of the plurality of concave mirrors constituting the annular mirror array is associated with a single communication target, and a phase image in which the modulated light modulated in the plurality of modulation regions is irradiated onto the concave mirror associated with the single communication target is set in the modulation section of the spatial light modulator.

9. a photodetector disposed on either side of the plurality of concave mirrors constituting the annular mirror array; The communication controller In an optical power measurement mode, a phase image is set in the spatial light modulator so that the modulated light modulated by the modulation unit of the spatial light modulator is irradiated toward the photodetector; measuring the optical power of the modulated light detected by the photodetector; 6. The transmitting device according to claim 5, wherein the output of the light source is adjusted in accordance with the measured optical power of the modulated light.

10. A transmitting device according to any one of claims 1 to 9; a receiving device for receiving a spatial optical signal transmitted from a communication target; a communication control device that acquires a signal based on the spatial optical signal transmitted from the communication target and received by the receiving device, performs processing according to the acquired signal, and causes the transmitting device to transmit a spatial optical signal according to the performed processing toward the communication target.

Images