Light transmitting device, communication device, control method, and program

Abstract

In order to transmit a stabilized spatial light signal to multiple communication targets, the present invention provides a light transmission device comprising: a light source; a spatial light modulator which has a modulation unit onto which light emitted from the light source is radiated, and which modulates the phase of the radiated light by means of the modulation unit; and a control unit which allocates modulation regions associated with respective communication targets to the modulation unit of the spatial light modulator, configures, in each modulation region, a phase image for forming an image used in communication with the communication target in the position of the communication target, and controls the light source such that light is radiated onto the modulation unit while the phase image is configured therein.

Description

[Technical field]

[0001] The present disclosure relates to a light transmitting device that transmits a spatial optical signal. [Background technology]

[0002] In optical space communication, optical signals that propagate through space (hereinafter also referred to as spatial optical signals) are sent and received without using a medium such as optical fiber. For example, if a phase-modulation type spatial light modulator is used, a spatial optical signal can be sent in any direction.

[0003] Patent Document 1 discloses a communication device including a phase-modulation type spatial light modulator. The device of the patent document includes a phase-modulation type spatial light modulator and a control unit for controlling the operation of the spatial light modulator. The control unit operates the spatial light modulator in a first operation pattern and a second operation pattern in one frame period. The first operation pattern includes a first light transmittable section in which a first signal light can be output and a first pause section in which the first signal light cannot be output in a predetermined cycle in the one frame period. The second operation pattern includes a second light transmittable section in which a second signal light can be output and a second pause section in which the second signal light cannot be output in a predetermined cycle. Each of the first light transmittable section and the second light transmittable section is longer than half the predetermined cycle. The second pause section is included in the first light transmittable section. The first pause section is included in the second light transmittable section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 026167 Summary of the Invention [Problem to be solved by the invention]

[0005] In the method of Patent Document 1, the phase modulation type spatial light modulation element is operated in two operation patterns to reduce the period during which the phase modulation type spatial light modulation element cannot transmit light. According to the method of Patent Document 1, continuous communication can be performed with a single communication target. However, in the method of Patent Document 1, when multiple communication targets are located in different positions / directions with respect to the communication device, it is not possible to irradiate the communication targets with an even beam. In order to establish stable communication with multiple communication targets, it is required to irradiate the communication targets with an even beam. In other words, the method of Patent Document 1 cannot establish stable communication with multiple communication targets.

[0006] An object of the present disclosure is to provide a light transmitting device and the like capable of transmitting stable spatial optical signals to multiple communication targets. [Means for solving the problem]

[0007] A light transmitting device according to one embodiment of the present disclosure includes a light source, a spatial light modulator having a modulation section to which light emitted from the light source is irradiated and which modulates the phase of the irradiated light in the modulation section, and a control section that assigns modulation areas corresponding to each of a plurality of communication targets to the modulation section of the spatial light modulator, sets a phase image for forming an image used in communication with the communication targets at the position of the communication targets in the modulation area, and controls the light source so that light is irradiated to the modulation section to which the phase image is set.

[0008] A control method of one embodiment of the present disclosure is a control method for a light transmitting device including a spatial light modulator that modulates the phase of light emitted from a light source using a modulation section, which assigns modulation areas corresponding to each of a plurality of communication targets to the modulation section of the spatial light modulator, sets a phase image for forming an image used in communication with the communication targets at the position of the communication targets in the modulation area, and controls the light source so that light is irradiated to the modulation section to which the phase image is set.

[0009] A program of one embodiment of the present disclosure is a program for controlling a light transmitting device having a spatial light modulator that modulates the phase of light emitted from a light source using a modulation section, and causes a computer to execute a process of assigning a modulation area corresponding to each of a plurality of communication targets to the modulation section of the spatial light modulator, a process of setting a phase image for forming an image used in communication with the communication targets at the position of the communication targets in the modulation area, and a process of controlling the light source so that light is irradiated to the modulation section to which the phase image is set. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide a light transmitting device or the like capable of transmitting stable spatial optical signals to a plurality of communication targets. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing an example of a configuration of a communication device according to a first embodiment. [Diagram 2] 2 is a conceptual diagram illustrating an example of a configuration of a light transmitting device included in the communication device according to the first embodiment. [Diagram 3] 3 is a conceptual diagram showing an example of a modulation region allocated to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to the first embodiment. FIG. [Figure 4] 3 is a conceptual diagram showing an example of a modulation region allocated to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to the first embodiment. FIG. [Diagram 5] 3 is a conceptual diagram showing an example of a modulation region allocated to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to the first embodiment. FIG. [Figure 6] 3 is a conceptual diagram showing an example of a modulation region allocated to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to the first embodiment. FIG. [Figure 7] 3 is a conceptual diagram showing an example of tiling of modulation regions allocated to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to the first embodiment. FIG. [Figure 8]4 is a conceptual diagram showing an example of a pattern set in a modulation area allocated to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to the first embodiment. FIG. [Figure 9] 6 is a conceptual diagram showing another example of a pattern set in a modulation region allocated to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to the first embodiment. FIG. [Figure 10] FIG. 2 is a conceptual diagram for explaining free space optical communication between communication devices in the first embodiment. [Figure 11] 4 is a conceptual diagram for explaining the position of an image displayed by projected light transmitted by the communication device in the first embodiment. FIG. [Figure 12] FIG. 1 is a conceptual diagram for explaining free space optical communication between communication devices in Related Art 1. [Figure 13] 10 is a conceptual diagram for explaining a position of an image displayed by projection light transmitted by a communication device in Related Art 1. FIG. [Figure 14] FIG. 13 is a conceptual diagram for explaining free space optical communication between communication devices in Related Art 2. [Figure 15] 13 is a conceptual diagram for explaining a position of an image displayed by projection light transmitted by a communication device in Related Art 2. FIG. [Figure 16] 2 is a block diagram showing an example of a light receiving device included in the communication device according to the first embodiment. FIG. [Figure 17] 2 is a block diagram showing an example of a light receiving device included in the communication control device according to the first embodiment. FIG. [Figure 18] FIG. 11 is a block diagram showing an example of a configuration of a communication device according to a second embodiment. [Figure 19] 11 is a conceptual diagram illustrating an example of the configuration of a light transmitting device included in a communication device according to a second embodiment. FIG. [Figure 20] 10 is a conceptual diagram showing an example of allocation of modulation regions to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to a second embodiment. FIG. [Figure 21] FIG. 13 is a block diagram showing an example of a configuration of a communication device according to a third embodiment. [Figure 22] 13 is a conceptual diagram illustrating an example of the configuration of a light transmitting device included in a communication device according to a third embodiment. FIG. [Figure 23] 13 is a graph showing an example of energy distribution of an image displayed by light projected from a light transmitting device included in a communication device according to a third embodiment. [Figure 24] 13A and 13B are conceptual diagrams for explaining division of a projection range of light projected from a light transmitting device included in a communication device according to a third embodiment into regions. [Diagram 25] 13 is a conceptual diagram for explaining an example of tiling of modulation regions assigned to a modulation section of a spatial light modulator of a light transmitting device included in a communication device according to a third embodiment. FIG. [Figure 26] 13A and 13B are conceptual diagrams for explaining an example of power control of projected light by a light transmitting device included in a communication device according to a third embodiment. [Figure 27] 13A and 13B are conceptual diagrams for explaining another example of power control of projected light by a light transmitting device included in a communication device according to the third embodiment. [Figure 28] FIG. 13 is a block diagram showing an example of a configuration of a light transmitting device according to a fourth embodiment. [Figure 29] FIG. 2 is a block diagram showing an example of a hardware configuration for implementing control and processing according to each embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the 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 addition, in all the drawings used to explain the following embodiments, the same reference numerals are used for similar parts unless otherwise specified. In addition, in the following embodiments, repeated explanations of similar configurations and operations may be omitted.

[0013] In all the drawings used to explain the following embodiments, the direction of the arrows in the drawings is an example, and does not limit the direction of light or signals. Furthermore, the lines showing the trajectory of light in the drawings are conceptual, and do not accurately represent the actual traveling direction or state of light. For example, in the drawings, the change in the traveling direction or state of light due to refraction, reflection, diffraction, diffusion, etc. at the interface between air and material may be omitted, or a light beam may be represented by a single line.

[0014] (First embodiment) First, a communication device according to a first embodiment will be described with reference to the drawings. The communication device of this embodiment performs optical space communication by transmitting and receiving optical signals (hereinafter, also referred to as spatial optical signals) propagating through space without using a medium such as an optical fiber. In this embodiment, an example of performing optical space communication simultaneously with multiple communication targets will be given.

[0015] (composition) 1 is a block diagram showing an example of the configuration of a communication device 1 according to the present embodiment. The communication device 1 according to the present embodiment includes a light transmitting device 10, a light receiving device 16, and a communication control device 19. In the following, the light transmitting device 10, the light receiving device 16, and the communication control device 19 will be described individually.

[0016] [Light transmitting device] First, the configuration of the light transmitting device 10 will be described with reference to the drawings. FIG. 2 is a conceptual diagram showing an example of the configuration of the light transmitting device 10. The light transmitting device 10 includes a light source 11, a spatial light modulator 13, and a control unit 14. The spatial light modulator 13 includes a modulation unit 130. FIG. 2 is a side view of the internal configuration of the light transmitting device 10 as seen from the lateral direction. FIG. 2 is conceptual and does not accurately represent the positional relationship between the components or the traveling direction of light. There is no particular limitation on the position of the control unit 14. The control unit 14 may be included in the communication control device 19.

[0017] The light source 11 includes an emitter 111 and a lens 112. The emitter 111 emits a laser beam 101 of a predetermined wavelength band toward the lens 112 in response to the control of the control unit 14. The lens 112 is disposed on the optical path of the laser beam 101 emitted from the emitter 111. The lens 112 is disposed so that the laser beam 101 emitted from the emitter 111 is irradiated according to the size of the modulation unit 130 of the spatial light modulator 13. When the modulation region corresponding to the light source 11 is set in the modulation unit 130, the lens 112 adjusts the irradiation range of the laser beam 101 according to the size of the modulation unit 130 of the spatial light modulator 13. The light 102 whose irradiation range has been adjusted by the lens 112 proceeds toward the modulation unit 130 of the spatial light modulator 13. In this embodiment, an example in which the light source 11 includes a single emitter 111 and lens 112 is given. In practice, it is required to control emitter 111 independently for each communication target. Therefore, light source 11 is configured to include a plurality of emitters 111 and lenses 112 so that the number of communication targets with which communication can be performed is the upper limit.

[0018] The wavelength of the laser light 101 emitted from the emitter 111 is not particularly limited and may be selected according to the application. For example, the emitter 111 emits the laser light 101 in a visible or infrared wavelength band. For example, in the case of near-infrared light of 800 to 900 nanometers (nm), the laser class can be increased, so that the sensitivity can be improved by about one order of magnitude compared to other wavelength bands. For example, in the case of infrared light in the 1.55 micrometer (μm) wavelength band, a high-output laser light source can be used. As a laser light source for infrared light in the 1.55 μm wavelength band, an aluminum gallium arsenide phosphide (AlGaAsP)-based laser light source or an indium gallium arsenide (InGaAs)-based laser light source can be used. The longer the wavelength of the laser light 101, the larger the diffraction angle can be and the higher the energy can be set.

[0019] The spatial light modulator 13 has a modulation section 130. A plurality of modulation regions are set in the modulation section 130. Each of the plurality of modulation regions is associated with each of a plurality of communication targets. A pattern (phase image) for each spatial light signal to be transmitted to the communication targets corresponding to each of the plurality of modulation regions is set in each of the plurality of modulation regions. When light 102 is irradiated to the modulation section 130 of the spatial light modulator 13 in a state in which a phase image is set, the irradiated light 102 is modulated. Modulated light 103 of the light 102 irradiated to the modulation section 130 is projected as projected light 105. The modulated light 103 (projected light 105) for each communication target is emitted from each of the plurality of modulation regions. For example, the modulated light 103 (projected light 105) emitted from each of the plurality of modulation regions is displayed as a dot-shaped image (also called a dot image) at the position of the communication target associated with each modulation region.

[0020] For example, the spatial light modulator 13 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 13 can be realized by LCOS (Liquid Crystal On Silicon). The spatial light modulator 13 may also be realized by MEMS (Micro Electro Mechanical System). In the phase modulation type spatial light modulator 13, 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 13 is used, if the output of the light source 11 is the same, the image can be displayed brighter than in other methods.

[0021] 3 to 6 are conceptual diagrams showing an example of a modulation area set in the modulation section 130 of the spatial light modulator 13. In order to accommodate a plurality of communication targets, a plurality of modulation areas are set in the modulation section 130. In this embodiment, an example is shown in which the light source 11 includes one emitter 111, but in practice, it is preferable that the light source 11 includes a plurality of emitters 111. If the light source includes a plurality of emitters 111, the light 102 irradiated to the plurality of modulation areas can be controlled independently.

[0022] 3 shows an example in which two modulation areas (modulation area A1, modulation area A2) are set in the modulation section 130. When there are two communication targets, it is sufficient that the modulation section 130 is divided into at least two modulation areas as shown in FIG.

[0023] 4 shows an example in which three modulation regions (modulation region B1, modulation region B2, and modulation region B3) are set in the modulation section 130. When there are three communication targets, as shown in FIG. 4, the modulation section 130 may be divided into at least three modulation regions.

[0024] 5 shows an example in which four modulation regions (modulation region C1, modulation region C2, modulation region C3, and modulation region C4) are set in the modulation section 130. When there are four communication targets, as shown in FIG. 5, the modulation section 130 may be divided into at least four modulation regions.

[0025] 6 shows an example in which six modulation regions (modulation region D1, modulation region D2, modulation region D3, modulation region D4, modulation region D5, modulation region D6) are set in the modulation section 130. When there are six communication targets, as shown in FIG. 6, the modulation section 130 may be divided into at least six modulation regions.

[0026] 3 to 6 are examples of division of the modulation section 130, and do not limit the number of divisions of the modulation section 130, the area of ​​each modulation region, or the shape of each modulation region. The number of divisions of the modulation section 130, the area of ​​each modulation region, and the shape of each modulation region can be set arbitrarily. A phase image corresponding to an image formed by the projection light 105 projected toward the communication target is set in a modulation region associated with a communication target. For example, a phase image does not need to be set in a modulation region not associated with a communication target.

[0027] FIG. 7 is a conceptual diagram for explaining a pattern (phase image) set in the modulation area 135 assigned to the modulation section 130 of the spatial light modulator 13. The modulation area 135 assigned to the modulation section 130 of the spatial light modulator 13 is divided into a plurality of areas (also called tiles 1350). For example, the modulation area 135 is divided into rectangular tiles 1350 with a desired aspect ratio. Each of the plurality of tiles 1350 is composed of a plurality of pixels. A phase image 1300 of an image formed by the projection light 105 projected toward a communication target associated with the modulation area 135 is assigned to each of the plurality of tiles 1350 set in the modulation area 135. For example, a phase image generated in advance is set to each of the plurality of tiles 1350. A phase image 1300 corresponding to an image projected toward a communication target associated with the modulation area 135 including the tiles 1350 is set to each of the plurality of tiles 1350. For example, a phase image 1300 that displays a dot image at the position of a communication target is set in each of the multiple tiles 1350, and the same phase image 1300 is assigned to each of the multiple tiles 1350 included in the same modulation area 135. A collection of the phase images 1300 assigned to the multiple tiles 1350 forms a phase image 1301. In other words, the phase image 1301, which is a collection of phase images 1300 in which image information to be displayed on a projected object by the projected light 105 is written, is set in the modulation area 135.

[0028] FIG. 8 is a conceptual diagram showing an example of a pattern (phase image) set in the modulation section 130 of the spatial light modulator 13. A composite image 1351 of a phase image 1301 and a shift image 1302 is set in the modulation section 130. The phase image 1301 is a pattern for forming a desired image. The shift image 1302 is a pattern for two-dimensionally moving the position of an image displayed by the projection light 105 using the phase image 1301. For example, the shift image 1302 is set so as to move the image in accordance with the output profile of the modulated light 103 emitted from the modulation section 130 of the spatial light modulator 13. When the shift image 1302 is synthesized, the image displayed by the projection light using the phase image 1301 can be shifted in the horizontal direction or the vertical direction. For example, when the modulated light 103 (projection light 105) is enlarged and projected, a projection optical system such as a Fourier transform lens or a projection lens may be used. For example, a composite image 1351 generated in advance may be stored in a storage unit (not shown). Fig. 8 is an example, and does not limit the patterns of the phase image 1301, the shift image 1302, and the composite image 1351.

[0029] FIG. 9 is a conceptual diagram showing another example of a pattern (phase image) set in the modulation section 130 of the spatial light modulator 13. FIG. 9 is an example using a virtual lens image. The wavefront of light can be controlled by phase control, similar to diffraction. When the phase changes spherically, a spherical difference is created in the wavefront, causing a lens effect. The virtual lens image changes the phase of the light 102 irradiated to the modulation section 130 of the spatial light modulator 13 spherically, causing a lens effect of focusing the light at a focusing point with a predetermined focal length. When a virtual lens image is used, a projection optical system such as a Fourier transform lens or a projection lens can be omitted. In the example of FIG. 9, the modulation section 130 is divided into two modulation regions, upper and lower, as in FIG. 3. FIG. 9 is a conceptual example, and does not accurately represent the patterns of the virtual lens image, shift image, and phase image that are actually used.

[0030] A composite image 1352A1 of the phase image 1301A1, the shift image 1302A1, and the virtual lens image 1303A1 is set in the upper modulation area (also called the modulation area A1) of the modulation section 130. The phase image 1301A1 and the shift image 1302A1 are set according to the modulation area A1. The virtual lens image 1303A1 is a pattern for converging light forming an image based on the phase image 1301A1 and the shift image 1302A1 to a converging point of the virtual lens image 1303A1. The virtual lens image 1303A1 is set according to the entire modulation section 130. The virtual lens image 1303A1 uses a portion (a portion within a range of a white dashed line) that overlaps with the phase image 1301A1 and the shift image 1302A1. A composite image 1352A2 of the phase image 1301A2, the shift image 1302A2, and the virtual lens image 1303A2 is set in the modulation area (also called the modulation area A2) on the lower side of the modulation unit 130. The phase image 1301A2 and the shift image 1302A2 are set according to the modulation area A2. The virtual lens image 1303A2 is a pattern for converging light forming an image based on the phase image 1301A2 and the shift image 1302A2 to a converging point of the virtual lens image 1303A2. The virtual lens image 1303A2 is set according to the entire modulation unit 130. The portion of the virtual lens image 1303A2 that overlaps with the phase image 1301A2 and the shift image 1302A2 (the portion within the range of the white dashed line) is used. In the example of FIG. 9, two modulation areas are set in the modulation unit 130. An arbitrary number of modulation areas can be set in the modulation unit 130. For each of the multiple modulation regions set in the modulation section 130, an individual composite image 1352 corresponding to the respective modulation region is set.

[0031] When light 102 is irradiated onto the modulation section 130 in a state in which patterns (phase images) such as a composite image 1351, a composite image 1352A, and a composite image 1352B are set in the modulation section 130, modulated light 103 is emitted from the modulation section 130 of the spatial light modulator 13. For example, modulated light 103 forming an image corresponding to the phase image 1300 of each tile 1350 is emitted from the modulation section 130 of the spatial light modulator 13. The more tiles 1350 are set in the modulation section 130, the clearer the image that can be displayed. On the other hand, if the number of pixels in each tile 1350 decreases, the resolution decreases. Therefore, the size and number of tiles 1350 set in the modulation section 130 are set according to the application.

[0032] A plurality of modulation regions 135 are set in the modulation section 130 of the spatial light modulator 13 in association with a plurality of communication targets. A phase image corresponding to an image displayed by the projection light 105 projected on the corresponding communication target is set in each of the plurality of modulation regions 135. The projection light 105 that displays an image of the same shape may be projected on each of the plurality of modulation regions 135, or the projection light 105 that displays an image of a different shape may be projected. In this embodiment, it is desirable to project the projection light 105 of the same power as much as possible toward the communication targets located at different distances / directions from the communication device 1. Therefore, the position where the image is displayed and the shape of the image to be displayed are set so that the projection light 105 of the same power as much as possible is projected for each communication target.

[0033] The control unit 14 controls the light source 11 and the spatial light modulator 13 in response to a light transmission instruction acquired from the communication control device 19. For example, the control unit 14 is realized by a microcomputer including a processor and a memory. The control unit 14 sets a phase image corresponding to the image to be projected in each of the multiple modulation areas 135 assigned to the modulation unit 130 in accordance with the aspect ratio of the modulation area set in the modulation unit 130 of the spatial light modulator 13. For example, the control unit 14 sets a phase image corresponding to an image suitable for optical space communication in each of the multiple modulation areas 135 assigned to the modulation unit 130. The phase image of the image to be projected may be stored in advance in a storage unit (not shown). There is no particular limitation on the shape or size of the image to be projected.

[0034] The control unit 14 sets a pattern (phase image) corresponding to an image formed by the projection light 105 in the modulation unit 130 of the spatial light modulator 13. The control unit 14 sets a phase image for each tile assigned to the modulation unit 130 of the spatial light modulator 13. The control unit 14 sets a phase image in the modulation unit 130 by driving the spatial light modulator 13 so that a parameter that determines the difference between the phase of the light 102 irradiated to the modulation unit 130 of the spatial light modulator 13 and the phase of the modulated light 103 reflected by the modulation unit 130 changes. The parameter that determines the difference between the phase of the light 102 irradiated to the modulation unit 130 of the spatial light modulator 13 and the phase of the modulated light 103 reflected by the modulation unit 130 is, for example, a parameter related to optical characteristics such as a refractive index and an optical path length. For example, the control unit 14 adjusts the optical characteristics of the modulation unit 130 by changing a voltage applied to the modulation unit 130 of the spatial light modulator 13. The phase distribution of the light 102 irradiated to the modulation section 130 of the phase modulation type spatial light modulator 13 is modulated according to the optical characteristics of the modulation section 130. The method of driving the spatial light modulator 13 by the control section 14 is determined according to the modulation method of the spatial light modulator 13.

[0035] The control unit 14 drives the emitter 111 of the light source 11 in a state where a phase image corresponding to an image to be displayed is set in the modulation unit 130. The control unit 14 drives the emitter 111 included in the light source 11 in accordance with the timing of transmitting the spatial light signal. As a result, the light 102 emitted from the light source 11 is irradiated onto a plurality of modulation regions 135 assigned to the modulation unit 130 of the spatial light modulator 13 in accordance with the timing at which the phase image is set in the modulation unit 130 of the spatial light modulator 13. The light 102 irradiated onto each of the plurality of modulation regions 135 assigned to the modulation unit 130 of the spatial light modulator 13 is modulated according to the phase image set in each of the plurality of modulation regions 135. The modulated light 103 modulated in the modulation unit 130 of the spatial light modulator 13 is projected as the projection light 105.

[0036] For example, a projection unit that enlarges and projects the modulated light 103 as projection light 105 may be disposed on the optical path of the modulated light 103. For example, the projection unit is realized by a projection optical system including a Fourier transform lens and a projection lens. For example, the projection unit is realized by a curved mirror having a curved reflecting surface that enlarges and reflects the modulated light 103. Details of the projection unit will not be described.

[0037] For example, a shield that passes the modulated light 103 (projected light 105) that forms a desired image and shields unnecessary light components may be disposed on the optical path of the modulated light 103 (projected light 105). For example, the shield blocks zero-order light and ghost images contained in the modulated light 103 (projected light 105). For example, the shield is an aperture in which a slit-shaped opening is formed in a portion that passes the light that forms the desired image. For example, the shield is a frame that shields unnecessary light components contained in the modulated light 103 (projected light 105) and defines the outer edge of the display area of ​​the projected light 105. For example, a zero-order light remover that removes zero-order light may be disposed on the optical path of the modulated light 103 (projected light 105). For example, the zero-order light remover includes a light absorbing member supported by a member that supports the light absorbing member. The light absorbing member is fixed on the optical path of the zero-order light contained in the modulated light 103 (projected light 105) by the support member. For example, the support member is made of a material that transmits the modulated light 103 (projected light 105), such as glass or plastic. For example, a black body such as carbon is used as the light absorbing member. When the wavelength of the laser light 101 used is fixed, it is preferable to use a light absorbing member made of a material that selectively absorbs light of the wavelength of the laser light 101.

[0038] [Projection example] Fig. 10 shows an example in which a light transmitting device 10 projects a projected light 105 toward a plurality of communication devices 1 as communication targets. In the example of Fig. 10, a projected light 105B is projected from a communication device 1A toward a communication device 1B, and a projected light 105C is projected toward a communication device 1C. The communication devices 1B and 1C are located at different distances / directions as viewed from the communication device 1A.

[0039] FIG. 11 is a conceptual diagram for explaining positions where pixels (dots) constituting an image are displayed by the projected light 105B and the projected light 105C projected from the communication device 1A in the positional relationship of FIG. 10. The projected light 105B and the projected light 105C are light modulated by phase images set in different modulation regions 135 assigned to the modulation section 130 of the spatial light modulator 13 of the communication device 1A. In FIG. 11, a dashed square (□) is illustrated at a position where a dot is displayed by the projected light 105B, and a dashed diamond (◇) is illustrated at a position where a dot is displayed by the projected light 105C. The communication device 1B is disposed at a position (□) where a dot is displayed by the projected light 105B. Therefore, an image including a dot 106B is irradiated onto the communication device 1B. The communication device 1C is disposed at a position (◇) where a dot is displayed by the projected light 105C. Therefore, an image including a dot 106C is irradiated onto the communication device 1C. In FIG. 11, the area of ​​dot 106B at the position of communication device 1B and the area of ​​dot 106C at the position of communication device 1C are the same, but in reality, their areas differ depending on the distance and position from communication device 1A.

[0040] 11, an image including dots 106B displayed by projected light 105B projected from communication device 1A is irradiated to communication device 1B but not to communication device 1C. On the other hand, an image including dots 106C displayed by projected light 105C projected from communication device 1A is irradiated to communication device 1C but not to communication device 1C. According to this embodiment, by setting a modulation area 135 for each communication target in the modulation section 130 of the spatial light modulator 13, it is possible to simultaneously irradiate spatial light signals to multiple communication devices 1 that would be outside the irradiation range if a single modulation area 135 was used.

[0041] Comparative Example 1 Here, a comparative example 1 including the problem solved by this embodiment will be described. Comparative example 1 includes a problem that a spatial light signal cannot be simultaneously irradiated to a plurality of communication targets due to their positional relationship. FIG. 12 is a conceptual diagram showing an example of projection of projected light in this comparative example. In the example of FIG. 12, projected light 150 is projected from communication device 100A toward communication device 100B and communication device 100C. Communication device 100B and communication device 100C are located at different distances / directions as viewed from communication device 100A. Communication device 100A also includes a spatial light modulator (not shown) similar to this embodiment. However, only a single modulation area is set in the modulation section of the spatial light modulator of communication device 100A.

[0042] FIG. 13 is a conceptual diagram for explaining the position where pixels (dots) constituting an image are displayed by the projection light 150 projected from the communication device 100A in the positional relationship of FIG. 12. The projection light 150 is light modulated by a phase image set in the modulation section of the spatial light modulator of the communication device 100A. In FIG. 13, a dashed circle (◯) is illustrated at the position where dots are displayed by the projection light 105B. The communication device 1B is disposed at the position (◯) where dots are displayed by the projection light 105B. Therefore, an image including a dot-shaped irradiation pattern 155 is irradiated onto the communication device 1B. In contrast, the communication device 1C is not disposed at the position where dots are displayed by the projection light 105C. Therefore, an image including dots is not irradiated onto the communication device 1C.

[0043] As shown in FIG. 13, an image including an irradiation pattern 155 displayed by the projection light 150 projected from the communication device 100A is projected onto the communication device 100B, but not onto the communication device 100C. In order to perform stable optical space communication using spatial optical signals, it is required that a beam of accurate power is projected onto an accurate position. In order to communicate with a plurality of communication targets, it is required to project the projection light 150 according to the number of communication targets, but it is difficult to accurately match the irradiation position of the projection light 150 to the position of the communication target. When a phase modulation type spatial light modulator is used, a gap is created between pixels. In Comparative Example 1, since the positions of the pixels constituting the image displayed by the projection light 150 are fixed, the projection light 150 is not projected onto the communication device 100C at the position of the gap between the pixels. That is, as shown in FIG. 13, when the position of the irradiation pattern 155 is aligned with the communication device 1B, the communication device 1C is deviated from the irradiation position of the image including the irradiation pattern 155. In the method of this comparative example, a single modulation region is set in the modulation section 130 of the spatial light modulator 13, so that a situation may arise in which spatial light signals cannot be transmitted to a plurality of communication devices 100 simultaneously.

[0044] Comparative Example 2 Next, a comparative example 2 including the problem solved by this embodiment will be described. Comparative example 2 includes a problem that when spatial light signals are simultaneously irradiated to a plurality of communication targets, the intensity of light irradiated to the communication targets becomes unstable. FIG. 14 is a conceptual diagram showing an example of projection of projected light in comparative example 2. In the example of FIG. 14, projected light 150 is projected from communication device 100A toward communication device 100B, communication device 100C, and communication device 100D. Communication device 100B, communication device 100C, and communication device 100D are located at different distances / directions as viewed from communication device 100A. Communication device 100A also includes a spatial light modulator (not shown) similar to this embodiment. However, only a single modulation area is set in the modulation section of the spatial light modulator of communication device 100A.

[0045] FIG. 15 is a conceptual diagram showing an example of an image displayed at the positions of the communication devices 100B, 100C, and 100D by the projection light 150 projected from the communication device 100A in the positional relationship of FIG. 14. The projection light 150 is light modulated by a phase image set in a modulation section of the spatial light modulator of the communication device 100A. In the example of FIG. 15, a phase image is set in the modulation section of the spatial light modulator of the communication device 100A so that a circular (◯) image (irradiation pattern 155) is displayed at the position of the communication device 100B. The communication device 100A projects the projection light 150 that forms a circular (◯) image (irradiation pattern 155) to the communication device 100B. In the example of FIG. 15, a distorted circular (elliptical) image is formed at the positions of the communication devices 100C and 100D.

[0046] As shown in FIG. 15, the irradiation pattern 155 displayed by the projected light 150 is projected in different shapes / sizes at the respective positions of the communication device 100B, the communication device 100C, and the communication device 100D. When a single modulation area is set in the modulation section of the spatial light modulator, the irradiation patterns 155 projected by each of the communication devices 100B, 100C, and 100D share the power of the laser light emitted from a light source (not shown) according to their areas. For example, when communication with the communication device 100C is stopped, the power of the projected light 150 projected on the communication devices 100B and 100D increases suddenly. In addition, when the irradiation pattern 155 suddenly changes, the power of the projected light 150 also changes. It is difficult to control such a change in the power of the irradiation pattern 155 even if the power of the light source is changed. Therefore, in the method of this comparative example, a situation may occur in which it is not possible to continue transmitting a spatial light signal of stable intensity in communication with multiple communication targets.

[0047] [Light receiving device] Next, the configuration of the light receiving device 16 will be described with reference to the drawings. FIG. 16 is a conceptual diagram for explaining the configuration of the light receiving device 16. The light receiving device 16 includes a light condenser 161, a light receiving element 17, and a receiving circuit 18. FIG. 16 shows an example in which there is only one light receiving element 17. It is more practical for the light receiving device 16 to be configured to include a plurality of light receiving elements 17. FIG. 16 is a plan view of the internal configuration of the light receiving device 16 as seen from above. There is no particular limitation on the position of the receiving circuit 18. The receiving circuit 18 may be disposed inside the light receiving device 16 or outside the light receiving device 16. The function of the receiving circuit 18 may also be included in the communication control device 19.

[0048] The condenser 161 is an optical element that condenses a spatial optical signal arriving from the outside. The spatial optical signal is incident on the incident surface of the condenser 161. The optical signal condensed by the condenser 161 is condensed toward the area where the light receiving element 17 is arranged. For example, the condenser 161 is a lens that condenses the incident spatial optical signal. For example, the condenser 161 is a light beam control element that guides the incident spatial optical signal toward the light receiving unit 170 of the light receiving element 17. For example, the condenser 161 may be configured by combining a lens and a light beam control element. The configuration of the condenser 161 is not particularly limited as long as it can condense the spatial optical signal toward the area where the light receiving element 17 is arranged. For example, a mechanism that guides the optical signal condensed by the condenser 161 toward the light receiving unit 170 of the light receiving element 17 may be added.

[0049] The light receiving element 17 receives light in a wavelength region of the spatial optical signal to be received. For example, the light receiving element 17 is sensitive to light in the visible region. For example, the light receiving element 17 is sensitive to light in the infrared region. The light receiving element 17 is sensitive to light in a wavelength region of, for example, 1.5 μm (micrometer). The wavelength region of light to which the light receiving element 17 is sensitive is not limited to the 1.5 μm region. The wavelength region of light received by the light receiving element 17 can be set arbitrarily according to the wavelength of the spatial optical signal to be received. The wavelength region of light received by the light receiving element 17 may be set to, for example, the 0.8 μm region, the 1.55 μm region, or the 2.2 μm region. The wavelength region of light received by the light receiving element 17 may be, for example, the 0.8 to 1 μm region. A shorter wavelength region is less absorbed by moisture in the atmosphere, and is therefore advantageous for optical space communication during rainfall. Furthermore, if the light receiving element 17 becomes saturated with intense sunlight, it cannot 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 provided in front of the light receiving element 17. For example, when polarized light is transmitted and received as the spatial optical signal, a polarizing plate that selectively passes the spatial optical signal in the polarization state of the object to be received may be provided in front of the light receiving element 17. For example, when a spatial optical signal in a specific wavelength band is transmitted and received, a band pass filter that selectively passes the spatial optical signal in the wavelength band to be received may be provided in front of the light receiving element 17.

[0050] For example, the light receiving element 17 can be realized by an element such as a photodiode or a phototransistor. For example, the light receiving element 17 is realized by an avalanche photodiode. The light receiving element 17 realized by the avalanche photodiode can support high-speed communication. The light receiving element 17 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. In order to improve the communication speed, it is preferable that the light receiving portion of the light receiving element 17 is as small as possible. For example, the light receiving portion of the light receiving element 17 has a square light receiving surface with one side of about 5 mm (millimeters). For example, the light receiving portion of the light receiving element 17 has a circular light receiving surface with a diameter of about 0.1 to 0.3 mm. The size and shape of the light receiving portion of the light receiving element 17 may be selected according to the wavelength band of the spatial optical signal, the communication speed, and the like.

[0051] The receiving circuit 18 acquires the signals output from each of the light receiving elements 17. The receiving circuit 18 amplifies the signals from each of the light receiving elements 17. The receiving circuit 18 decodes the amplified signals and analyzes the signals from the communication target. The signals decoded by the receiving circuit 18 are used for any purpose. There are no particular limitations on the use of the signals decoded by the receiving circuit 18.

[0052] [Communication Control Device] Next, the configuration of the communication control device 19 will be described with reference to the drawings. FIG. 17 is a block diagram for explaining an example of the configuration of the communication control device 19. The communication control device 19 has a condition storage unit 191, a light transmission condition generation unit 192, a light transmission instruction unit 193, a signal acquisition unit 195, a signal analysis unit 196, and a signal generation unit 197. For example, the communication control device 19 is realized by a microcomputer including a processor and a memory. The communication control device 19 may be implemented in a server or cloud connected to the light transmitting device 10 and the light receiving device 16 via a network.

[0053] The condition storage unit 191 stores patterns such as a phase image, a shift image, and a virtual lens image corresponding to the projection light 105 to be transmitted by the light transmitting device 10. The patterns stored in the condition storage unit 191 are set in the modulation unit 130 of the spatial light modulator 13. The condition storage unit 191 also stores projection conditions including a light source control condition for controlling the light source 11 of the light transmitting device 10 and a modulator control condition for controlling the spatial light modulator 13 of the light transmitting device 10. The light source control condition is a condition including a timing for emitting the laser light 101 from the light source 11 of the light transmitting device 10. The modulator control condition is a condition for setting a pattern in the modulation unit 130 of the spatial light modulator 13. By coordinating the light source control condition and the modulator control condition, the projection light 105 according to the pattern set in the modulation unit 130 of the spatial light modulator 13 is projected.

[0054] The light transmission condition generating unit 192 acquires a signal from the signal generating unit 197. The light transmission condition generating unit 192 generates light transmission conditions for transmitting information included in the acquired signal based on the conditions stored in the condition storage unit 191. For example, the light transmission condition generating unit 192 selects a pattern for transmitting information included in the acquired signal based on the projection conditions stored in the condition storage unit 191. For example, the light transmission condition generating unit 192 generates light transmission conditions for setting a pattern corresponding to an image projected to transmit information included in the acquired signal to the modulation unit 130 of the spatial light modulator 13. For example, the light transmission condition generating unit 192 generates light transmission conditions for setting a phase image corresponding to the image to be projected to the modulation unit 130 of the spatial light modulator 13 in accordance with the aspect ratio of the modulation region set in the modulation unit 130 of the spatial light modulator 13.

[0055] The light-sending instruction unit 193 outputs a light-sending instruction for controlling the light source 11 and the spatial light modulator 13 of the light-sending device 10 to the light-sending device 10 based on the light-sending conditions set by the light-sending condition generation unit 192 .

[0056] The signal acquiring unit 195 acquires a signal decoded by the light receiving device 16 from the light receiving device 16. The signal acquiring unit 195 also acquires a signal to which signal processing has been applied by the light receiving device 16 from the light receiving device 16. For example, the signal acquired by the signal acquiring unit 195 includes a scanned communication target and a response transmitted from a communication target during communication in response to the spatial optical signal transmitted from the communication device 1. The signal acquiring unit 195 outputs the acquired signal to the signal analyzing unit 196.

[0057] The signal analysis unit 196 analyzes the signal acquired by the signal acquisition unit 195. For example, the signal analysis unit 196 analyzes information included in the signal according to the type of the signal. For example, the signal types include a scan signal and a communication signal. There is no particular limitation on the type of the signal analyzed by the signal analysis unit 196. The signal analysis unit 196 outputs the signal analysis result to the signal generation unit 197.

[0058] The signal generation unit 197 acquires the signal analysis result by the signal analysis unit 196. The signal generation unit 197 generates a transmission signal according to the signal analysis result. The transmission signal includes the content of communication with the communication target and the content used to scan the communication target. The signal generation unit 197 generates a transmission signal for each communication target. The signal generation unit 197 generates a scan signal and a communication signal as the transmission signal. The scan signal is a signal used to scan the communication target. The communication signal is a signal including information exchanged with the communication target. The signal generation unit 197 outputs the generated signal to the light transmission condition generation unit 192.

[0059] For example, the communication signal is a signal transmitted and received between communication devices 1 with which communication has been established when a communication path for transmitting and receiving a spatial optical signal is determined. The communication signal includes information to be transmitted to a communication target. The information carried on the communication signal may be predetermined, or may be information corresponding to information included in a communication signal from the communication target. For example, when a communication signal with content corresponding to information included in a communication signal from a communication target is generated, the information included in the communication signal transmitted from the communication target is displayed on a display device (not shown). For example, an operator who has confirmed the information displayed on the display device inputs a response to the displayed information to the communication control device 19 (signal generating unit 197) via an input device (not shown). For example, the signal generating unit 197 generates a communication signal including the input information. There is no particular limitation on the information to be included in the communication signal.

[0060] As described above, the communication device of the present embodiment includes a light transmitting device, a light receiving device, and a communication control device. The light receiving device receives a spatial light signal transmitted from a communication target. The light receiving device decodes a signal included in the received spatial light signal. The communication control device acquires the signal decoded by the light receiving device. The communication control device causes the light transmitting device to transmit a spatial light signal corresponding to the acquired signal. The light transmitting device has a light source, a spatial light modulator, and a control unit. The light source emits light. The spatial light modulator has a modulation unit to which the light emitted from the light source is irradiated. The spatial light modulator modulates the phase of the irradiated light by the modulation unit. The control unit assigns a modulation area corresponding to each of the multiple communication targets to the modulation unit of the spatial light modulator. The control unit sets a phase image for forming an image used in communication with the communication target at the position of the communication target in the modulation area. The control unit sets a phase image for displaying an image at the position of the communication target associated with each of the multiple modulation areas in each of the multiple modulation areas assigned to the modulation unit of the spatial light modulator. The control unit controls the light source so that light is irradiated to the modulation unit to which the phase image is set.

[0061] In this embodiment, a modulation area for each of the multiple communication targets is set in the modulation section of the spatial light modulator in association with each of the multiple communication targets. A phase image for each communication target is set in the modulation area. According to this embodiment, since a modulation area for each communication target is set in the modulation section, a stable spatial light signal can be transmitted to the multiple communication targets. Furthermore, according to this aspect, the spatial light signal can be accurately irradiated toward the position of the communication target. Therefore, according to this aspect, a spatial light signal that appropriately displays an image (e.g., a dot image) used for communication can be transmitted to the communication target.

[0062] In one aspect of this embodiment, the control unit sets, for each of the multiple communication targets, a phase image for displaying an image at the position of the communication target corresponding to each of the multiple modulation areas in each of the multiple modulation areas assigned to the modulation unit of the spatial light modulator. According to this aspect, the spatial light signal can be accurately irradiated toward the position of each of the multiple communication targets. Therefore, according to this aspect, the spatial light signal that appropriately displays an image (e.g., a dot image) used for communication can be transmitted to each of the multiple communication targets.

[0063] In one aspect of this embodiment, the control unit sets a composite image of the phase image and the shift image in each of a plurality of modulation areas assigned to the modulation unit of the spatial light modulator. The phase image is a pattern for displaying an image. The shift image is a pattern for changing the display position of an image (e.g., a dot image) at the position of a communication target associated with each of the plurality of modulation areas. According to this aspect, by using the shift image, the display position of the image can be changed to any position within the projection range.

[0064] In one aspect of the present embodiment, the control unit sets a composite image of the phase image, the shift image, and the virtual lens image in each of a plurality of modulation areas assigned to the modulation unit of the spatial light modulator. The phase image is a pattern for displaying an image. The shift image is a pattern for changing the display position of an image (e.g., a dot image) at the position of a communication target associated with each of the plurality of modulation areas. The virtual lens image is a pattern for enlarging and projecting an image. According to this aspect, the display position of an image can be changed to any position within the projection range by using the shift image. According to this aspect, the display position of an image can be changed to any position within the projection range by using the shift image. Also, according to this aspect, the image can be enlarged and projected by using the virtual lens image.

[0065] Second Embodiment Next, a communication device according to a second embodiment will be described with reference to the drawings. The communication device of this embodiment differs from the first embodiment in that the modulation area allocated to the modulation section of the spatial light modulator is dynamically changed.

[0066] (composition) 18 is a block diagram showing an example of the configuration of the communication device 2 of this embodiment. The communication device 2 of this embodiment includes a light transmitting device 20, a light receiving device 26, and a communication control device 29. The light receiving device 26 and the communication control device 29 are similar to the corresponding configurations of the first embodiment. In the following, a description of the light receiving device 26 and the communication control device 29 will be omitted, and the configuration of the light transmitting device 20 will be described in detail. In this embodiment, an example will be given in which the light transmitting conditions of the spatial optical signal are set by the light transmitting device 20. The light transmitting conditions of the spatial optical signal may be set by the communication control device 29.

[0067] [Light transmitting device] FIG. 19 is a conceptual diagram showing an example of the configuration of the light transmitting device 20. The light transmitting device 20 includes a light source 21, a spatial light modulator 23, and a control unit 24. The spatial light modulator 23 includes a modulation unit 230. FIG. 19 is a side view of the internal configuration of the light transmitting device 20 seen from the lateral direction. FIG. 19 is a conceptual diagram, and does not accurately represent the positional relationship between the components and the traveling direction of light. The position of the control unit 24 is not particularly limited. The control unit 24 may be included in the communication control device 29. The light source 21 and the spatial light modulator 23 are the same as the corresponding configurations in the first embodiment. The control unit 24 is the same as the corresponding configurations in the first embodiment, except for the method of allocating the modulation area to the modulation unit 230 of the spatial light modulator 23. In the following, the description will be focused on the method of allocating the modulation area to the modulation unit 230 of the spatial light modulator 23 by the control unit 24.

[0068] 20 is a conceptual diagram for explaining a method of allocating a modulation region to the modulation section 130 of the spatial light modulator 13. The control section 24 allocates at least one modulation region to the modulation section 230 in accordance with the number of communication targets. When allocating a modulation region to the modulation section 230, the control section 24 sets at least one spare region (also called a spare region) that is not allocated to a communication target. For example, a pattern (phase image) in which modulated light 203 is not emitted in response to irradiation of light 202 is set in the spare region.

[0069] FIG. 20(E) is an example of modulation region allocation when there are three communication targets. The control unit 24 sets the modulation region E1, modulation region E2, modulation region E3, and reserve region V1 in the modulation unit 230. The modulation region E1, modulation region E2, modulation region E3, and reserve region V1 are set in the modulation unit 230. The modulation region E1, modulation region E2, and modulation region E3 are modulation regions associated with any of the communication targets. The reserve region V1 is a reserve region that is not assigned to any of the communication targets.

[0070] Fig. 20(F) is an example of modulation region allocation when the number of communication targets increases from three to four. The control unit 24 divides the reserve region V1 into a modulation region F and a reserve region V2. The modulation unit 130 is set with modulation region E1, modulation region E2, modulation region E3, modulation region F, and reserve region V2. The modulation region E1, modulation region E2, modulation region E3, and modulation region F are modulation regions associated with any of the communication targets. The reserve region V2 is a reserve region that is not assigned to any of the communication targets.

[0071] FIG. 20(G) is an example of modulation region allocation when the number of communication targets increases from four to five. The control unit 24 divides the reserve region V2 into modulation region G and reserve region V3. The modulation unit 130 is set with modulation region E1, modulation region E2, modulation region E3, modulation region F, modulation region G, and reserve region V3. The modulation region E1, modulation region E2, modulation region E3, modulation region F, and modulation region G are modulation regions associated with any of the communication targets. The reserve region V3 is a reserve region that is not assigned to any of the communication targets.

[0072] FIG. 20(H) is an example of modulation region allocation when the number of communication targets is reduced from five to four. The control unit 24 sets the reserve region V2 by integrating the modulation region G and the reserve region V3. The reserve region V2 is the same region as FIG. 20(F). The modulation unit 130 sets the modulation region E1, the modulation region E2, the modulation region E3, the modulation region F, and the reserve region V2. The modulation region E1, the modulation region E2, the modulation region E3, and the modulation region F are modulation regions associated with any of the communication targets. The reserve region V2 is a reserve region that is not assigned to any of the communication targets.

[0073] As described above, the control unit 24 dynamically changes the number of modulation areas assigned to the modulation unit 230 of the spatial light modulator 23 in response to an increase or decrease in the number of communication targets. When dynamically changing the modulation area, the control unit 24 sets a reserve area that is not assigned to the communication targets. The control unit 24 sets a new modulation area to the reserve area in response to an increase in the number of communication targets. The control unit 24 integrates any of the modulation areas into the reserve area in response to a decrease in the number of communication targets. In other words, the control unit 24 increases or decreases the number of modulation areas set in the reserve area of ​​the modulation unit 230 of the spatial light modulator 23 in response to an increase or decrease in the number of communication targets. For example, the control unit 24 can change the number of modulation areas assigned to the modulation unit 230 of the spatial light modulator 23 for each opportunity to project the projection light 205. For example, the control unit 24 may change the area of ​​the modulation area in response to the output profile of the modulated light 203 emitted from the modulation unit 230 of the spatial light modulator 23. For example, the control unit 24 sets the area of ​​each of the multiple modulation areas in response to the output profile so that the power of each of the multiple modulation areas is uniform.

[0074] As described above, the communication device of the present embodiment includes a light transmitting device, a light receiving device, and a communication control device. The light receiving device receives a spatial light signal transmitted from a communication target. The light receiving device decodes a signal included in the received spatial light signal. The communication control device acquires the signal decoded by the light receiving device. The communication control device causes the light transmitting device to transmit a spatial light signal corresponding to the acquired signal. The light transmitting device has a light source, a spatial light modulator, and a control unit. The light source emits light. The spatial light modulator has a modulation unit to which the light emitted from the light source is irradiated. The spatial light modulator modulates the phase of the irradiated light by the modulation unit. The control unit assigns a modulation area corresponding to each of the multiple communication targets to the modulation unit of the spatial light modulator. The control unit sets a phase image for forming an image used in communication with the communication target at the position of the communication target in the modulation area. The control unit dynamically changes the number of multiple modulation areas assigned to the modulation unit of the spatial light modulator according to the number of multiple communication targets. The control unit controls the light source so that light is irradiated to the modulation unit to which the phase image is set.

[0075] A modulation area is set in the modulation section of the spatial light modulator for each communication target. Therefore, if the number of modulation areas is fixed, when all modulation areas are in use, communication with a new communication target cannot be established. In this embodiment, the number of multiple modulation areas assigned to the modulation section of the spatial light modulator in association with each of the multiple communication targets is dynamically changed according to the number of multiple communication targets. Therefore, according to this embodiment, a situation in which the modulation area cannot be used is unlikely to occur, so that continuous optical space communication can be realized between multiple communication targets.

[0076] In one aspect of the present embodiment, the control unit sets a spare region that is not used for communication with the communication target in the modulation unit. According to this aspect, a spare region that is not used for communication is set and a modulation region is dynamically assigned to the spare region, thereby enabling flexible response according to communication conditions.

[0077] In one aspect of the present embodiment, the control unit dynamically allocates a part of the reserve region as the modulation region in response to an increase in the number of communication targets. According to this aspect, when the number of communication targets increases, continuous free space optical communication can be realized between the communication targets by dynamically allocating the modulation region to the reserve region.

[0078] In one aspect of this embodiment, the control unit integrates the modulation area that is no longer used for communication with the communication target into the reserve area in response to a decrease in the number of communication targets. If the modulation area that is not used for communication is left as it is, power may be wasted due to the unused modulation area. According to this aspect, when the number of communication targets decreases, the power consumption of the spatial light modulator can be optimized by integrating the modulation area that is no longer used for communication into the reserve area.

[0079] (Third embodiment) Next, a communication device according to a third embodiment will be described with reference to the drawings. The communication device of this embodiment differs from the first and second embodiments in that the tiling of the modulation area set in the modulation unit is adjusted according to the output profile of the image displayed in the projection range. The method of this embodiment may be combined with the method of the second embodiment.

[0080] (composition) FIG. 21 is a block diagram showing an example of the configuration of the communication device 2 of this embodiment. The communication device 3 of this embodiment includes a light transmitting device 30, a light receiving device 36, and a communication control device 39. The light receiving device 36 and the communication control device 39 are similar to the corresponding configurations of the first embodiment. In the following, the description of the light receiving device 36 and the communication control device 39 will be omitted, and the configuration of the light transmitting device 30 will be described in detail. In this embodiment, an example will be given in which the light transmitting conditions of the spatial optical signal are set by the light transmitting device 30. The light transmitting conditions of the spatial optical signal may be set by the communication control device 39.

[0081] [Light transmitting device] FIG. 22 is a conceptual diagram showing an example of the configuration of the light transmitting device 30. The light transmitting device 30 includes a light source 31, a spatial light modulator 33, and a control unit 34. The spatial light modulator 33 includes a modulation unit 330. FIG. 22 is a side view of the internal configuration of the light transmitting device 30 seen from the lateral direction. FIG. 22 is a conceptual diagram, and does not accurately represent the positional relationship between the components and the traveling direction of light. The position of the control unit 34 is not particularly limited. The control unit 34 may be included in the communication control device 39. The light source 31 and the spatial light modulator 33 are the same as the corresponding configurations in the first embodiment. The control unit 34 is the same as the corresponding configurations in the first embodiment, except for the tiling method in the modulation unit 330 of the spatial light modulator 33. In the following, the description will be focused on the tiling method in the modulation unit 330 of the spatial light modulator 33 by the control unit 34.

[0082] FIG. 23 is an example of an energy distribution (also called an output profile) of an image (dot image) formed on a projection surface by the projection light 305. The horizontal axis of the graph in FIG. 23 indicates the position on the projection surface. The vertical axis of the graph in FIG. 23 indicates the power of the dot image displayed by the projection light 305 for each position on the projection surface. FIG. 23 shows a one-dimensional energy distribution on a straight line passing through the center of the projection range. The actual output profile shows a two-dimensional energy distribution. The actual output profile shows an energy distribution that is distributed concentrically with the center of the projection range as the center. The output profile of the dot image on the projection surface shows a nonlinear power distribution. The output profile of the dot image on the projection surface changes depending on the projection optical system for projecting the projection light 305. For example, when a mechanism for removing the zero-order light contained in the projection light 305 is introduced, a dot image is not displayed at the projection position of the zero-order light, so a profile with the power applied to the center part of the projection range is obtained. In the example of Fig. 23, the power of the dot image is maximum when it is displayed in the center of the projection range. The power of the dot image decreases as it moves away from the center of the projection range. In other words, the power of the dot image formed on the projection surface is not uniform within the projection surface.

[0083] As in the example of Figure 23, if the power of the dot image on the projection surface is not uniform, the output of the spatial light signal used for communication with the communication target will not be stable. If the output of the spatial light signal is not stable, stable communication cannot be maintained. In order to maintain stable communication, it is preferable that the power of the dot image is as flat as possible within the projection surface.

[0084] The power EP of the dot image can be estimated by the relationship between the output W, the output profile P, the phase image factor PF, and the number of tiles N. The output W is the output of the light 302 emitted from the light source 31, which is irradiated to the modulation unit 330 of the spatial light modulator 33. The output profile P is the power of the dot image for each position on the projection surface. The phase image factor PF includes various factors. For example, the phase image factor PF includes a factor related to the brightness of the phase image. For example, the phase image factor PF includes a factor related to the normalized value of the illumination light used when generating the phase image. For example, the phase image factor PF is a factor related to the presence or absence and shape of a noise sweeping area set when generating the phase image. The number of tiles N is the number of tiles for each modulation area. For example, the power EP of the projection light 305 can be expressed by the relationship shown in the following formula 1. P = W × P × F × N (1) It is difficult to finely adjust the output W and the output profile P in response to changes in communication conditions. They can be adjusted by changing some factor. However, it is difficult to equalize the power of the dot image over the entire area of ​​the projection surface by adjusting only the phase image factor PF. Therefore, in this embodiment, the power of the dot image on the projection surface is adjusted by combining the adjustment of the phase image factor PF and the number of tiles N. In forming a dot image, the number N of tiles used to form the dot image is important. If the number N of tiles is small, the dot image will deteriorate. Therefore, in this embodiment, the number N of tiles is set to be increased while keeping the tile resolution low.

[0085] In this embodiment, the phase image set in multiple tiles included in the modulation area assigned to the modulation section 330 of the spatial light modulator 33 and the number of tiles assigned to the modulation area are set according to the position on the projection surface.

[0086] FIG. 24 is a conceptual graph diagram for explaining an example of power control of a dot image by the light transmitting device 30. The graph in FIG. 24 shows an output profile of a dot image formed on a projection surface by the projection light 305. The output profile in FIG. 24 is the same as the output profile in FIG. 23. The graph in FIG. 24 also illustrates a target value of the power of the dot image. For example, the target value of the power is set according to the class of the laser light used in spatial optical communication. For example, assuming a class 1 visible light laser, the target value of the power is set to about 0.39 watts. For example, assuming a class 1 infrared light laser in the 1.5 micrometer band, the target value of the power is set to about 10 milliwatts. FIG. 24 shows an example of one-dimensionally dividing a projection surface into five regions on a straight line passing through the center of the projection surface. In the example in FIG. 24, the projection surface is divided into five regions (region a, region b, region c, region d, and region e). In reality, a two-dimensional projection surface is divided into regions in a lattice pattern.

[0087] The light transmitting device 30 sets, for each region, a phase image in which the lower limit of the output profile is the target power value. As seen in the output profile, the power of the dot image decreases as it moves away from the center of the projection surface. Therefore, the further away an area is from the center of the projection range, the more a phase image is set that displays a brighter dot image. In contrast, the closer an area is to the center of the projection range, the more a phase image is set that displays a darker dot image. The phase image for displaying the dot image in each region reduces the number of tiles set in the modulation region as it moves closer to the center of the projection surface within the range of each region.

[0088] FIG. 25 is a conceptual diagram showing an example of reducing the number of tiles set in a modulation area allocated to the modulation section 330 of the spatial light modulator 33. The modulation area includes a plurality of tiles. A phase image for displaying a dot image on a projection surface is displayed in each of the plurality of tiles. The same phase image is set in the plurality of tiles included in the same modulation area. The phase image 3301 is a pattern set in the modulation area. The phase image 3301 is composed of the phase images set in each of the plurality of tiles included in the modulation area.

[0089] The phase image 3302 in FIG. 25 is an example in which the number of tiles (active tiles) used to display a dot image is reduced. The light 302 irradiated to tiles not used to display a dot image (also called inactive tiles) is not converted to modulated light 303 and contributes to the zeroth order light. The inactive tiles are not reflected in the display of the dot image displayed on the projection surface. Even if the number of active tiles is reduced, the displayed dot image remains the same. Therefore, by reducing the number of active tiles, the power of the dot image can be reduced without changing the displayed dot image. In other words, the power of the dot image can be adjusted by adjusting the number of tiles used to display the dot image.

[0090] The power of the dot image is maximized when phase images are set in all of the tiles included in the modulation area. Therefore, the power of the dot image displayed by the projection light 305 projected in a state where phase images are set in all tiles is set to the target value of the power of the dot image displayed in each area. In each area, a state is set in which phase images are set in all tiles included in the modulation area in order to display the dot image at the position farthest from the center of the projection range. The closer the display position of the dot image is to the center of the projection range, the closer the power of the dot image in each area can be brought to the target value by reducing the number of tiles used to display the dot image.

[0091] FIG. 26 is a conceptual diagram for explaining an example of power control of a dot image. FIG. 26 is an enlarged view of the area a and the area b in FIG. 24. The light transmitting device 30 sets a phase image for displaying a dot image showing a power equivalent to the target value of power at the left end point of the area a in the modulation area assigned to the modulation unit 330 of the spatial light modulator 33. When the phase image set in the modulation area is shifted so that the position of the dot image moves toward the center of the projection range, the power increases as shown by the dotted line according to the tendency of the output profile. As for the area a, the power increases from the left end to the right end of the area a. At the position where the power increases as shown by the dotted line, if the number of tiles in the modulation area is reduced so that the power of the dot image approaches the target value, the power of the dot image in the area a can be kept constant. In the example of FIG. 26, the output profile intersects with the target value of power within the range of the area a. Therefore, for the position where the output profile intersects with the target value of power, a phase image showing a power equivalent to the target value of power may be set in the modulation area. From the position where the output profile and the target value of power intersect to the right end of the region b, the number of tiles in the modulation region may be reduced so that the power of the dot image approaches the target value. As for the regions c and d in FIG. 24, the number of tiles in the modulation region may be reduced according to the position of the projection range, similar to the region b. As for the region e in FIG. 24, a phase image for displaying a dot image showing a power equivalent to the target value of power at the point at the right end of the region e is set in the modulation region assigned to the modulation unit 330 of the spatial light modulator 33. When the phase image set in the modulation region is shifted so that the position of the dot image moves away from the center of the projection range, the power decreases according to the tendency of the output profile. As for the region e, the power decreases from the left end to the right end of the region e. At the position where the power increases, if the number of tiles in the modulation region is reduced so that the power of the dot image approaches the target value, the power of the dot image in the region e can be kept constant.

[0092] FIG. 27 is a conceptual diagram for explaining another example of power control of a dot image. FIG. 27 is an enlarged view of the area a and the area b in FIG. 24. The light transmitting device 30 sets a phase image indicating a power equivalent to the target value of the power at the left end point of the area a in the modulation area assigned to the modulation unit 330 of the spatial light modulator 33. When the phase image set in the modulation area is shifted so that the position of the dot image moves toward the center of the projection range, the power increases as shown by the dotted line according to the tendency of the output profile. At the position where the power increases as shown by the dotted line, if the number of tiles in the modulation area is reduced so that the power of the dot image approaches the target value, the power of the dot image in the area a can be kept constant. In the example of FIG. 27, the number of tiles in the modulation area is reduced so that the power of the dot image approaches the target value in the entire range of the area a. As with the area a, the power of the dot image in the area b may be controlled so that it approaches the target value. Explanations of the areas c, d, and e are omitted.

[0093] For example, a table may be prepared in which the number of inactive tiles corresponds to the position of the projection range. By referring to the table, the light transmitting device 30 can set the number of inactive tiles according to the position where the dot image is to be displayed. The position of the inactive tiles in the modulation area can be set arbitrarily.

[0094] For example, a table may be prepared in which a phase image tiled with active tiles and inactive tiles is associated with a position in the projection range. The phase image tiled with active tiles and inactive tiles includes active tiles in a number corresponding to the power of the dot image. By referring to the table, the light transmitting device 30 can set a phase image in which the inactive tiles are patterned according to the position where the dot image is to be displayed. The position of the inactive tiles in the modulation area can be set arbitrarily.

[0095] For example, a map may be prepared in which a phase image in which active tiles and inactive tiles are tiled is mapped to the position of the projection range. The phase image in which active tiles and inactive tiles are tiled includes active tiles in a number corresponding to the power of the dot image. For example, the light transmitting device 30 may select a phase image from the map according to the position in which the dot image is to be displayed. The position of the inactive tile in the modulation area may be set arbitrarily.

[0096] As described above, the communication device of the present embodiment includes a light transmitting device, a light receiving device, and a communication control device. The light receiving device receives a spatial optical signal transmitted from a communication target. The light receiving device decodes a signal included in the received spatial optical signal. The communication control device acquires the signal decoded by the light receiving device. The communication control device causes the light transmitting device to transmit a spatial optical signal corresponding to the acquired signal. The light transmitting device has a light source, a spatial light modulator, and a control unit. The light source emits light. The spatial light modulator has a modulation unit to which the light emitted from the light source is irradiated. The spatial light modulator modulates the phase of the irradiated light by the modulation unit. The control unit assigns a modulation area corresponding to each of the multiple communication targets to the modulation unit of the spatial light modulator. The control unit sets a phase image for forming an image used in communication with the communication target at the position of the communication target in the modulation area. The control unit changes the phase image set in the multiple tiles assigned to the modulation area according to the projection position of the image in the projection range so as to bring the power of the image displayed in the projection range of the image closer to a target value. The control unit controls the light source so that light is irradiated onto the modulation unit on which the phase image is set.

[0097] The power of the image displayed in the projection range varies depending on the position inside the projection range. In this embodiment, the phase images set in the tiles assigned to the modulation area are changed according to the projection position of the image in the projection range, so that the power of the image displayed in the projection range approaches a target value. Therefore, according to this embodiment, the image displayed in the projection range can be smoothed. That is, according to this aspect, the power of the spatial optical signal irradiated to the communication target can be stabilized.

[0098] In one aspect of the present embodiment, the control unit sets one of the tiles allocated to the modulation area as an inactive tile to which no phase image is set. The control unit adjusts the number of inactive tiles according to the projection position of the image in the projection area so that the power of the image displayed in the projection area approaches a target value. According to this aspect, the power of the projected image can be adjusted by changing the number of tiles constituting the modulation area.

[0099] In one aspect of the present embodiment, the control unit changes the phase image set in the tiles assigned to the modulation area for each area set within the projection range. According to this aspect, the power of the projected image can be adjusted by setting a phase image for each area set within the projection range.

[0100] (Fourth embodiment) Next, a light transmitting device according to a fourth embodiment will be described with reference to the drawings. The light transmitting device of this embodiment has a simplified configuration of the light transmitting devices of the first to third embodiments. FIG. 28 is a conceptual diagram showing an example of the configuration of a light transmitting device 40 of this embodiment. The light transmitting device 40 includes a light source 41 and a spatial light modulator 43.

[0101] The light source 41 emits light 402. The spatial light modulator 43 has a modulation section 430 onto which the light 402 emitted from the light source 41 is irradiated. The spatial light modulator 43 modulates the phase of the irradiated light 402 by the modulation section 430. The control section 44 assigns modulation regions corresponding to each of a plurality of communication targets to the modulation section 430 of the spatial light modulator 43. The control section 44 sets a phase image for forming an image used in communication with the communication target at the position of the communication target in the modulation region. The control section 44 controls the light source 41 so that the light 402 is irradiated to the modulation section 430 to which the phase image is set.

[0102] As described above, in this embodiment, a modulation area for each of the multiple communication targets is set in the modulation section of the spatial light modulator in association with each of the multiple communication targets. A phase image for each communication target is set in the modulation area. According to this embodiment, since a modulation area for each communication target is set in the modulation section, a stable spatial light signal can be transmitted to the multiple communication targets.

[0103] (Hardware) Here, a hardware configuration for executing the control and processing according to each embodiment of the present disclosure will be described using an information processing device 90 in Fig. 29 as an example. Note that the information processing device 90 in Fig. 29 is an example configuration for executing the control and processing according to each embodiment, and does not limit the scope of the present disclosure.

[0104] As shown in Fig. 29, 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. 29, the 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. In addition, the processor 91, the main storage device 92, the auxiliary storage device 93, and the input / output interface 95 are connected to a network such as the Internet or an intranet via the communication interface 96.

[0105] The processor 91 loads a program stored in the auxiliary storage device 93 or the like into the main storage device 92. The processor 91 executes the program loaded into the main storage device 92. In this embodiment, a software program installed in the information processing device 90 may be used. The processor 91 executes the control and processing according to this embodiment.

[0106] 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 in the main memory device 92. The main memory device 92 is realized by a volatile memory such as a dynamic random access memory (DRAM). Furthermore, a non-volatile memory such as a magnetoresistive random access memory (MRAM) may be configured / added to the main memory device 92.

[0107] 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 a flash memory. Note that it is also possible to configure the main storage device 92 to store various data and omit the auxiliary storage device 93.

[0108] 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 through 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.

[0109] Input devices such as a keyboard, a mouse, and a touch panel may be connected to the information processing device 90 as necessary. These input devices are used to input information and settings. When a touch panel is used as an input device, the display screen of the display device may also serve as an interface for the input device. Data communication between the processor 91 and the input devices may be mediated by an input / output interface 95.

[0110] The information processing device 90 may be equipped with a display device for displaying information. When the display device is equipped, the information processing device 90 is preferably equipped with a display control device (not shown) for controlling the display of the display device. The display device may be connected to the information processing device 90 via the input / output interface 95.

[0111] The information processing device 90 may also be provided with a drive device. The drive device mediates between the processor 91 and a recording medium (program recording medium) for reading data and programs from the recording medium, writing the processing results of the information processing device 90 to the recording medium, and the like. The drive device may be connected to the information processing device 90 via an input / output interface 95.

[0112] The above is an example of a hardware configuration for enabling the control and processing according to each embodiment of the present invention. The hardware configuration in FIG. 29 is an example of a hardware configuration for executing the control and processing according to each embodiment, and does not limit the scope of the present invention. In addition, a program for causing a computer to execute the control and processing according to each embodiment is also included in the scope of the present invention. Furthermore, a program recording medium on which a program according to each embodiment is recorded is also included in the scope of the present invention. The recording medium can be realized, for example, by an optical recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc). The recording medium may be realized by a semiconductor recording medium such as a USB (Universal Serial Bus) memory or an SD (Secure Digital) card. In addition, the recording medium may be realized by 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.

[0113] The components of each embodiment may be combined in any manner. Furthermore, the components of each embodiment may be realized by software or by a circuit.

[0114] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-mentioned 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.

[0115] A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes. (Appendix 1) A light source; a spatial light modulator having a modulation section that is irradiated with light emitted from the light source, the spatial light modulator modulating a phase of the irradiated light by the modulation section; a control unit that assigns a modulation area corresponding to each of a plurality of communication targets to the modulation unit of the spatial light modulator, sets a phase image in the modulation area for forming an image used in communication with the communication targets at the position of the communication targets, and controls the light source so that the light is irradiated to the modulation unit to which the phase image is set. (Appendix 2) The control unit is 2. The light transmitting device according to claim 1, wherein the phase image is set in each of a plurality of modulation areas assigned to the modulation section of the spatial light modulator, for displaying the image at the position of the communication target corresponding to each of the plurality of modulation areas. (Appendix 3) The control unit is The light transmitting device according to claim 1, wherein the phase image is set for each of the plurality of communication targets in each of the plurality of modulation areas assigned to the modulation section of the spatial light modulator, for displaying the image at the position of the communication target corresponding to each of the plurality of modulation areas. (Appendix 4) The control unit is A light transmitting device as described in any one of appendices 1 to 3, wherein a composite image obtained by combining the phase image for displaying the image and a shift image for changing the display position of the image at the position of the communication target corresponding to each of the plurality of modulation areas is set in each of the plurality of modulation areas assigned to the modulation section of the spatial light modulator. (Appendix 5) The control unit is A light transmitting device as described in any one of appendixes 1 to 3, in which a composite image obtained by combining the phase image for displaying the image, a shift image for changing the display position of the image at the position of the communication target corresponding to each of the plurality of modulation areas, and a virtual lens image for enlarging and projecting the image is set in each of the plurality of modulation areas assigned to the modulation section of the spatial light modulator. (Appendix 6) The control unit is 6. The light transmitting device according to claim 1, wherein a number of the plurality of modulation regions assigned to the modulation section of the spatial light modulator is dynamically changed according to a number of the plurality of communication targets. (Appendix 7) The control unit is 7. The light transmitting device according to claim 6, wherein a spare region that is not used for communication with the communication target is set in the modulation section. (Appendix 8) The control unit is 8. The light transmitting device according to claim 7, wherein a part of the reserve area is dynamically allocated as the modulation area in response to an increase in the number of communication targets. (Appendix 9) The control unit is 9. The light transmitting device according to claim 7 or 8, wherein the modulation area that is no longer used for communication with the communication targets is integrated into the spare area in response to a decrease in the number of the communication targets. (Appendix 10) The control unit is A light transmitting device as described in any one of appendix 1 to 9, which changes the phase images set in multiple tiles assigned to the modulation area according to the projection position of the image in the projection range so as to bring the power of the image displayed in the projection range of the image closer to a target value. (Appendix 11) The control unit is A light transmitting device as described in Appendix 10, which sets one of the multiple tiles assigned to the modulation area as an inactive tile on which the phase image is not set, and adjusts the number of inactive tiles so that the power of the image displayed in the projection range approaches the target value depending on the projection position of the image in the projection range. (Appendix 12) The control unit is 12. The light transmitting device according to claim 11, wherein the phase images set in the tiles assigned to the modulation area are changed for each area set within the projection range. (Appendix 13) A light transmitting device according to any one of Supplementary Notes 1 to 12; a light receiving device that receives a spatial optical signal transmitted from a communication target and decodes a signal included in the received spatial optical signal; a communication control device that acquires the signal decoded by the light receiving device, and causes the light transmitting device to transmit a spatial light signal corresponding to the acquired signal. (Appendix 14) A method for controlling a light transmitting device including a spatial light modulator that modulates the phase of light emitted from a light source using a modulation unit, comprising the steps of: The computer Allocating a modulation area corresponding to each of a plurality of communication targets to the modulation section of the spatial light modulator; A phase image for forming an image used in communication with the communication target at the position of the communication target is set in the modulation area; A control method for controlling the light source so that the light is irradiated onto the modulation section on which the phase image is set. (Appendix 15) A program for controlling a light transmitting device including a spatial light modulator that modulates the phase of light emitted from a light source using a modulation unit, A process of allocating a modulation area corresponding to each of a plurality of communication targets to the modulation section of the spatial light modulator; A process of setting a phase image in the modulation area to form an image used in communication with the communication target at the position of the communication target; and controlling the light source so that the light is irradiated to the modulation section to which the phase image is set. [Explanation of symbols]

[0116] 1, 2, 3 Communication Equipment 10, 20, 30, 40 Light transmitting device 11, 21, 31, 41 light source 13, 23, 33, 43 Spatial Light Modulator 14, 24, 34, 44 Control section 16, 26, 36 Photodetector 17 Photodetector 18 Receiving circuit 19, 29, 39 Communication control device 111 Emitter 112 Lens 161 Concentrator 191 Condition memory section 192 Light transmission condition generation section 193 Light transmission instruction section 195 Signal Acquisition Unit 196 Signal analysis section 197 Signal Generation Unit

Claims

1. A light source; a spatial light modulator having a modulation section that is irradiated with light emitted from the light source, the spatial light modulator modulating a phase of the irradiated light by the modulation section; a control means for allocating a modulation area corresponding to each of a plurality of communication targets to the modulation section of the spatial light modulator, setting a phase image in the modulation area for forming an image used in communication with the communication targets at the position of the communication targets, and controlling the light source so that the light is irradiated to the modulation section to which the phase image is set.

2. The control means The light transmitting device according to claim 1 , wherein the phase image is set in each of the plurality of modulation areas assigned to the modulation section of the spatial light modulator to display the image at the position of the communication target corresponding to each of the plurality of modulation areas.

3. The control means The light transmitting device according to claim 1, wherein the phase image for displaying the image at the position of the communication target corresponding to each of the plurality of modulation areas assigned to the modulation section of the spatial light modulator is set for each of the plurality of communication targets.

4. The control means A light transmitting device as described in any one of claims 1 to 3, wherein a composite image obtained by combining the phase image for displaying the image and a shift image for changing the display position of the image at the position of the communication target corresponding to each of the plurality of modulation areas is set in each of the plurality of modulation areas assigned to the modulation section of the spatial light modulator.

5. The control means A light transmitting device as described in any one of claims 1 to 3, wherein a composite image obtained by combining the phase image for displaying the image, a shift image for changing the display position of the image at the position of the communication target corresponding to each of the multiple modulation areas, and a virtual lens image for enlarging and projecting the image is set in each of the multiple modulation areas assigned to the modulation section of the spatial light modulator.

6. The control means 6. The light transmitting device according to claim 1, wherein a number of the plurality of modulation regions assigned to the modulation section of the spatial light modulator is dynamically changed according to a number of the plurality of communication targets.

7. The control means A light transmitting device as described in any one of claims 1 to 6, wherein the phase images set in multiple tiles assigned to the modulation area are changed depending on the projection position of the image in the projection range so as to bring the power of the image displayed in the projection range of the image closer to a target value.

8. A light transmitting device according to any one of claims 1 to 7, a light receiving device that receives a spatial optical signal transmitted from a communication target and decodes a signal included in the received spatial optical signal; a communication control device that acquires the signal decoded by the light receiving device, and causes the light transmitting device to transmit a spatial light signal corresponding to the acquired signal.

9. A method for controlling a light transmitting device including a spatial light modulator that modulates the phase of light emitted from a light source using a modulation unit, comprising the steps of: The computer Allocating a modulation area corresponding to each of a plurality of communication targets to the modulation section of the spatial light modulator; A phase image for forming an image used in communication with the communication target at the position of the communication target is set in the modulation area; A control method for controlling the light source so that the light is irradiated onto the modulation section on which the phase image is set.

10. A program for controlling a light transmitting device including a spatial light modulator that modulates the phase of light emitted from a light source using a modulation unit, A process of allocating a modulation area corresponding to each of a plurality of communication targets to the modulation section of the spatial light modulator; A process of setting a phase image in the modulation area to form an image used in communication with the communication target at the position of the communication target; and controlling the light source so that the light is irradiated to the modulation section to which the phase image is set.

Images