Light irradiation device, optical wireless communication system, and light irradiation method

Abstract

This light emitting device emits an emission beam from a light generation device onto an object. The light emitting device includes: an image forming optical system; an optical member that emits, toward an image plane of the image forming optical system, light which enters through the image forming optical system, and that emits the emission beam from the light generation device which enters through a conjugate plane conjugate with the image plane, toward the image forming optical system; an imaging device that captures at least a portion of an image of an object formed on the image plane by the image forming optical system; a position changing device that changes the position on the conjugate plane of the emission beam from the light generation device to change an emission position of the emission beam emitted from the image forming optical system; and a control device that controls the position changing device on the basis of imaging results of the imaging device. The control device controls the position changing device on the basis of the imaging results of the imaging device to emit the emission beam emitted from the image forming optical system onto at least a portion of the object.

Description

Light irradiation device and optical wireless communication system

[0001] The present invention relates to a light irradiation device and an optical wireless communication system.

[0002] 2. Description of the Related Art Optical communication methods using laser light are known. For example, Patent Document 1 describes an optical communication device.

[0003] U.S. Pat. No. 5,065,455

[0004] The light irradiation device of the present invention is a light irradiation device that irradiates an object with an irradiation beam from a light generating device, and includes an imaging optical system, an optical element that emits light incident through the imaging optical system toward an image plane of the imaging optical system and emits the irradiation beam from the light generating device that is incident through a conjugate plane conjugate to the image plane toward the imaging optical system, an imaging device that captures at least a portion of the image of the object formed on the image plane by the imaging optical system, a position changing device that changes the position of the irradiation beam from the light generating device on the conjugate plane and changes the irradiation position of the irradiation beam emitted from the imaging optical system, and a control device that controls the position changing device based on the imaging result of the imaging device, and the control device controls the position changing device based on the imaging result of the imaging device to irradiate at least a portion of the object with the irradiation beam emitted from the imaging optical system.

[0005] FIG. 1 is a schematic configuration diagram showing a light irradiation system according to a first embodiment. FIG. 1 is a schematic configuration diagram showing a light irradiation device according to a first embodiment. FIG. 2 is a diagram for explaining the configuration of the periphery of a light transmitting and receiving optical element according to the first embodiment. FIG. 3 is a diagram showing a first example of optical wireless communication according to the first embodiment. FIG. 4 is a diagram showing a second example of optical wireless communication according to the first embodiment. FIG. 5 is a diagram showing a third example of optical wireless communication according to the first embodiment. FIG. 6 is a schematic configuration diagram showing a modified example of the light irradiation system according to the first embodiment. FIG. 7 is a schematic configuration diagram showing a light irradiation device according to a second embodiment. FIG. 8 is a schematic configuration diagram showing a light irradiation device according to a third embodiment. FIG. 9 is a schematic configuration diagram showing a light irradiation device according to a fourth embodiment. FIG. 10 is a schematic diagram for explaining a case where a light reflection region according to the fourth embodiment is divided into light receiving and light transmitting. FIG. 11 is a schematic diagram for explaining a case where a light transmitting and receiving optical element according to the fourth embodiment is arranged at a defocus position. FIG. 11 is a schematic configuration diagram showing a light irradiation device according to a fifth embodiment. FIG. 12 is a schematic configuration diagram showing a light irradiation device according to a sixth embodiment. FIG. 13 is a diagram showing an example of a moving body according to the sixth embodiment. FIG. 14 is a schematic configuration diagram showing a light irradiation device according to a seventh embodiment. FIG. 15 is a schematic configuration diagram showing a light irradiation device according to an eighth embodiment. FIG. 13 is a schematic configuration diagram illustrating a light irradiation device according to a ninth embodiment.

[0006] Hereinafter, a light irradiation device and an optical wireless communication system according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure may differ from the scale and number of the actual structure in order to make each configuration easier to understand.

[0007] [First Embodiment] Fig. 1 is a schematic diagram showing the configuration of a light irradiation system according to a first embodiment. A light irradiation system 100 will be described with reference to the same figure. As shown in Fig. 1, the light irradiation system 100 includes a plurality of light irradiation devices 1 that irradiate an object with an irradiation beam 51. The irradiation beam 51 is an electromagnetic wave, such as light. The irradiation beam 51 broadly includes light such as ultraviolet light, infrared light, visible light, and terahertz waves (terahertz light). In the first embodiment, the irradiation beam 51 is light modulated based on information. In other words, the light irradiation device 1 transmits information by irradiating light.

[0008] The object onto which the light irradiation device 1 irradiates the irradiation beam 51 may be a part of the object onto which the light irradiation device 1 irradiates the irradiation beam 51, or may be the entire object onto which the irradiation beam 51 is irradiated. In the first embodiment, the object may be, for example, another light irradiation device 1 different from the light irradiation device itself. The light irradiation device 1 performs optical wireless communication by irradiating the other light irradiation device 1 different from the light irradiation device itself with the irradiation beam 51. The light irradiation system 100 includes a plurality of light irradiation devices 1, and thereby performs optical wireless communication between the plurality of light irradiation devices 1.

[0009] The light irradiation device 1 may be installed on a movable body. The movable body may be, for example, any robot such as a vertical articulated robot, a gimbal, a manned / unmanned vehicle, a manned / unmanned aerial vehicle, a manned / unmanned ship, a manned / unmanned submersible, or the like. An unmanned aerial vehicle may also be referred to as a drone. The light irradiation device 1 may be installed on a surface outside or inside the movable body. Here, the movable body includes a body that can be repositioned or a body whose position relative to the device itself can change. For example, in the case of a robot, even if the base part is fixed, the position of the part on the end effector side can change, so the movable body may also be referred to as a movable body. The movable body may also be referred to as a moving body.

[0010] Furthermore, the light irradiation device 1 may be fixed and installed on any surface, such as the surface of land or an artificial structure such as a building. Land includes any topography, such as a flat surface or a slope, and also includes the bottom of water, such as the bottom of the sea or a lake. Artificial structures such as buildings include civil engineering structures. The surface of an artificial structure includes the floor, wall, and ceiling of a building, as well as the outer surface of a building. Buildings are not limited to those traded as real estate, but also include those traded as movable property. Furthermore, "fixed" is not limited to cases where the object is permanently fixed, but also includes cases where the object is temporarily fixed.

[0011] In the example shown in FIG. 1 , the light irradiation system 100 includes a light irradiation device 1-1 and a light irradiation device 1-2 as the light irradiation device 1. The light irradiation device 1-1 transmits information by emitting an irradiation beam 51 to the light irradiation device 1-2, and the light irradiation device 1-2 receives the information by receiving the irradiation beam 51 emitted from the light irradiation device 1-1. Similarly, the light irradiation device 1-2 transmits information by emitting an irradiation beam 51 to the light irradiation device 1-1, and the light irradiation device 1-1 receives the information by receiving the irradiation beam 51 emitted from the light irradiation device 1-2. Here, the object may be at least a part of the device with which communication is performed. For example, for the light irradiation device 1-1, at least a part of the light irradiation device 1-2 may be an object, and for the light irradiation device 1-2, at least a part of the light irradiation device 1-1 may be an object.

[0012] FIG. 2 is a schematic diagram illustrating the configuration of a light irradiation device according to the first embodiment. The functional configuration of the light irradiation device 1 will be described with reference to the same figure. The description may be made using an xyz three-dimensional Cartesian coordinate system with x, y, and z axes. As shown in FIG. 2, the light irradiation device 1 includes an imaging optical system 10, an optical element 20, an imaging device 30, a position changing device 40, a control device 50, and a light generating device 60. The light irradiation device 1 does not necessarily have to include the light generating device 60, and the light irradiation device 1 and the light generating device 60 may be separate entities. When describing the light irradiation device 1 as an example of the above-described light irradiation device 1-1, it may be referred to as a light irradiation device 1A. Furthermore, when the above-described imaging optical system 10, optical element 20, imaging device 30, position change device 40, control device 50, and light generation device 60 are expressed as the configuration of light irradiation device 1A, they may be referred to as the imaging optical system 10A, optical element 20A, imaging device 30A, position change device 40A, control device 50A, and light generation device 60A, respectively. Similarly, they may be referred to as light irradiation device 1B, which is an example of the above-described light irradiation device 1-2. When the imaging optical system 10, optical element 20, imaging device 30, position change device 40, control device 50, and light generation device 60 are expressed as the configuration of light irradiation device 1B, they may be referred to as the imaging optical system 10B, optical element 20B, imaging device 30B, position change device 40B, control device 50B, and light generation device 60B, respectively. In the xyz three-dimensional Cartesian coordinate system, the x-axis indicates the direction of the optical axis 111 of the imaging optical system 10, and the plane formed by the y-axis and z-axis indicates a plane perpendicular to the optical axis 111 of the imaging optical system 10.

[0013] The components of the light irradiation device 1 will be described using an example in which the light irradiation device 1A and the light irradiation device 1B communicate optically wirelessly. For example, the light irradiation device 1A irradiates (transmits) light for optical wireless communication as an irradiation beam 51 to the light irradiation device 1B, which is an object. The light irradiation device 1A also receives (receives) the light for optical wireless communication (irradiation beam 51) emitted from the light irradiation device 1B. The light generating device 60A generates light (irradiation beam 51) to be irradiated to the light irradiation device 1B. The light (irradiation beam 51) generated by the light generating device 60A is emitted toward the light irradiation device 1B via the optical element 20A and the imaging optical system 10A. Details of the optical element 20 and the imaging optical system 10 will be described later. The light generating device 60A also receives the light (irradiation beam) emitted from the light irradiation device 1B via the imaging optical system 10A and the optical element 20A.

[0014] As an example, the light generating device 60 includes a communication substrate 62, an optical fiber 61, and a light transmitting and receiving optical element 41 including at least a portion of the optical fiber 61. The light transmitting and receiving optical element 41 may also be referred to as a light transmitting and receiving optical member. When the communication substrate 62, the optical fiber 61, and the light transmitting and receiving optical element 41 are expressed as components of the light generating device 60A, they may be referred to as the communication substrate 62A, the optical fiber 61A, and the light transmitting and receiving optical element 41A. Similarly, when the communication substrate 62, the optical fiber 61, and the light transmitting and receiving optical element 41 are expressed as components of the light generating device 60B, they may be referred to as the communication substrate 62B, the optical fiber 61B, and the light transmitting and receiving optical element 41B, respectively.

[0015] The communication board 62 converts one of an electrical signal for information communication and light (irradiation beam 51) for optical wireless communication into the other. For example, the communication board 62 generates light (irradiation beam 51) for optical wireless communication with the light irradiation device 1B. The communication board 62A generates light (irradiation beam 51) for optical wireless communication by converting an electrical signal for information communication into light (irradiation beam 51). Also, for example, the communication board 62A receives the irradiation beam 51 emitted from the light irradiation device 1B. The communication board 62A converts the irradiation beam 51 from the light irradiation device 1B into an electrical signal. Note that the communication board 62 may also be referred to as an optical communication board.

[0016] The optical fiber 61 transmits light (irradiation beam 51) for optical wireless communication between the communication board 62 and the light transmitting and receiving optical element 41. For example, the optical fiber 61A transmits light (irradiation beam 51) generated by the communication board 62A from the communication board 62A to the light transmitting and receiving optical element 41A. Also, for example, the optical fiber 61A transmits light (irradiation beam 51) received by the light transmitting and receiving optical element 41A from the light irradiation device 1B via the imaging optical system 10A and the optical member 20A to the communication board 62A.

[0017] The light transmitting and receiving optical element 41 emits light (illumination beam 51) incident via the optical fiber 61 toward the optical member 20. The light transmitting and receiving optical element 41 also emits light (illumination beam 51) incident via the imaging optical system 10 and the optical member 20 to the optical fiber 61. For example, the light transmitting and receiving optical element 41 includes at least an emission end of the optical fiber 61 that emits light (illumination beam 51) from the communication board 62.

[0018] For example, the light transmitting and receiving optical element 41A emits light (illumination beam 51) incident from the communication board 62A via the optical fiber 61A toward the optical member 20. The light transmitting and receiving optical element 41A emits light (illumination beam 51) incident from the light irradiation device 1B via the imaging optical system 10A and the optical member 20A to the optical fiber 61A. The light transmitting and receiving optical element 41 is also disposed on or near a conjugate plane 220 that is optically conjugate with an image plane 210 of the imaging optical system 10, which will be described later. For example, as shown in FIG. 2 , a light emitting end 223 of the light transmitting and receiving optical element 41 on the optical member 20 side is disposed slightly away from the conjugate plane 220 in a direction away from the optical member 20. Furthermore, the light emitting end 223 of the light transmitting / receiving optical element 41 on the optical member 20 side may be positioned on the conjugate plane 220 of the imaging optical system 10, or may be positioned slightly closer to the optical member 20 than the conjugate plane 220.

[0019] For example, the light transmitting and receiving optical element 41 emits light (illumination beam 51) from the optical fiber 61 toward the optical member 20 via the conjugate surface 220 of the imaging optical system 10, and also emits light (illumination beam 51) that has passed through the imaging optical system 10 and the optical member 20 and entered through the conjugate surface 220 toward the optical fiber 61. For example, the light transmitting and receiving optical element 41 is configured to be able to receive, in a stationary state, light (illumination beam 51) that has passed through the same optical path as the light (illumination beam 51) emitted from the imaging optical system 10 from the light transmitting and receiving optical element 41 through the conjugate surface 220 and the optical member 20 before being emitted from the imaging optical system 10. Note that the light transmitting and receiving optical element 41 may also be configured to receive light (illumination beam 51) that has passed through an optical path different from the optical path that the light (illumination beam 51) emitted from the imaging optical system 10 passes through the conjugate surface 220 and the optical member 20 before being emitted from the imaging optical system 10. The light transmitting and receiving optical element 41 may be composed of at least one optical member. The configuration of the light transmitting and receiving optical element 41 will be described later.

[0020] The light transmitting and receiving optical element 41 may be referred to as a light emitting unit or a light emitting device because it emits light (irradiation beam 51) to the optical member 20. Also, the light transmitting and receiving optical element 41 may be referred to as a light receiving unit or a light receiving device because it receives light (irradiation beam 51) from the optical member 20. Also, the light transmitting and receiving optical element 41 may be referred to as a light transmitting and receiving unit or a light transmitting and receiving device because it emits light (irradiation beam 51) to the optical member 20 and receives light (irradiation beam 51) from the optical member 20.

[0021] In addition, at least one of the communication board 62, the optical fiber 61, the optical member 20, and the imaging optical system 10 may be referred to as a light emitting unit or a light emitting device, not limited to the light transmitting and receiving optical element 41. In other words, it can be said that the light irradiation device 1 includes a light emitting unit or a light emitting device that emits the irradiation beam 51. In addition, the light generating device 60 may be referred to as a light emitting unit or a light emitting device. In addition, the light irradiation device 1 may be referred to as a light emitting unit or a light emitting device.

[0022] In addition, not only the light transmitting and receiving optical element 41, but also at least one of the imaging optical system 10, the optical member 20, the optical fiber 61, and the communication board 62 may be referred to as a light receiving unit or a light receiving device. In other words, it can be said that the light irradiation device 1 is equipped with a light receiving unit or a light receiving device that receives the irradiation beam 51. In addition, the light generating device 60 may be referred to as a light receiving unit or a light receiving device. In addition, the light generating device 60 may be referred to as a light receiving unit or a light receiving device. In addition, the light irradiation device 1 may be referred to as a light receiving unit or a light receiving device.

[0023] Incidentally, at least one of the imaging optical system 10, the optical member 20, the optical fiber 61, and the communication board 62 may be referred to as a light transmitting and receiving unit or a light transmitting and receiving device, without being limited to the light transmitting and receiving optical element 41. In other words, it can be said that the light irradiation device 1 includes a light transmitting and receiving unit or a light transmitting and receiving device that emits the irradiation beam 51 and receives the irradiation beam 51. Incidentally, the light generating device 60 may be referred to as a light transmitting and receiving unit, a light transmitting and receiving device, a photoelectric conversion unit, or a photoelectric conversion device. Incidentally, the light irradiation device 1 may be referred to as a light transmitting and receiving unit or a light transmitting and receiving device.

[0024] Furthermore, the light irradiation device 1 does not need to include at least one of the communication board 62, optical fiber 61, and light transmitting and receiving optical element 41 of the light generating device 60, and the light irradiation device 1 may be separate from at least one of the communication board 62, optical fiber 61, and light transmitting and receiving optical element 41.

[0025] The imaging optical system 10 forms a reduced image of at least a portion of an object on the image plane 210. In this embodiment in which the light irradiation system 100 performs optical wireless communication, the object may be the device that is the other party of the communication, i.e., at least a portion of the light irradiation device 1, as described above. The imaging optical system 10 may form a reduced image of at least a portion of the other party's light irradiation device 1 with which the optical wireless communication is performed on the image plane 210. Furthermore, the imaging optical system 10 may emit light (irradiation beam 51) for optical wireless communication emitted from the optical member 20 via the light transmitting / receiving optical element 41 toward the other party's light irradiation device 1. Furthermore, the imaging optical system 10 may receive the irradiation beam 51 from the other party's light irradiation device 1 and emit it toward the optical member 20. For example, the imaging optical system 10A may form a reduced image of at least a portion of the light irradiation device 1B on the image plane 210. The imaging optical system 10A may also emit light (irradiation beam 51) for optical wireless communication emitted from the optical member 20A via the light transmitting and receiving optical element 41A toward the light irradiation device 1B. The imaging optical system 10A may also receive the irradiation beam 51 from the light irradiation device 1B and emit it toward the optical member 20A.

[0026] An imaging device 30 is disposed near an image plane 210 of the imaging optical system 10. The imaging device 30 captures a reduced image of at least a portion of an object formed on the image plane 210. The imaging device 30 includes an imaging element 31 having a plurality of pixels arranged on the imaging surface. It can also be said that the imaging element 31 captures a reduced image of at least a portion of an object formed on the image plane 210. For example, the imaging surface of the imaging element 31 may be disposed on the image plane 210 of the imaging optical system 10. Furthermore, the imaging surface of the imaging element 31 does not have to be disposed on the image plane 210 of the imaging optical system 10, but may be disposed near the image plane 210. Note that the imaging element 31 may be an imaging element capable of outputting color image data (e.g., an RGB image sensor) or an imaging element capable of outputting monochrome image data (e.g., a monochrome image sensor).

[0027] The imaging optical system 10 does not have to form a reduced image of at least a part of the object on the image plane 210. For example, the imaging optical system 10 may be configured to form an enlarged image or an equal-size image of at least a part of the object on the image plane 210.

[0028] It is desirable that the angle of view of the imaging optical system 10 is wide, and for example, it is preferable that the maximum angle of view of the imaging optical system 10 is 170° or more. The maximum angle of view of the imaging optical system 10 on the object side may be less than 170°, for example, 60°. The angle of view of the imaging optical system 10 may be approximately 180°. When the imaging optical system 10 has an angle of view of approximately 180°, an omnidirectional camera can be configured by arranging two light irradiation devices 1 so that they face in directions that are 180° apart and face opposite each other.

[0029] The imaging optical system 10 may be telecentric on the side of the conjugate plane 220. To make the imaging optical system 10 telecentric on the side of the conjugate plane 220, for example, an aperture stop (not shown) may be provided at a predetermined position. This aperture stop does not have to be provided in the imaging optical system 10. Alternatively, the imaging optical system 10 may be telecentric on the side of the conjugate plane 220 by limiting the effective diameter of a predetermined lens constituting the imaging optical system 10 to a predetermined size.

[0030] The imaging optical system 10 may also be non-telecentric on the object side. To make the imaging optical system 10 non-telecentric on the object side, for example, an aperture stop (not shown) may be provided at a predetermined position. This aperture stop does not have to be provided in the imaging optical system 10. The imaging optical system 10 may also be non-telecentric on the object side by limiting the effective diameter of a predetermined lens constituting the imaging optical system 10 to a predetermined size. The imaging optical system 10 may also include multiple optical elements. The multiple optical elements included in the imaging optical system 10 may include well-known optical elements. For example, the imaging optical system 10 may include multiple lens elements, or may include at least one lens element and at least one reflecting element.

[0031] The optical element 20 is disposed on the image plane 210 side of the imaging optical system 10 and divides the optical path of the imaging optical system 10. Here, the imaging optical system 10 forms an image plane 210 and a conjugate plane 220 on each of the optical paths divided by the optical element 20. When the image plane 210 formed by the imaging optical system 10 is defined as a first image plane, the conjugate plane 220 may be referred to as a second image plane formed by the imaging optical system 10. It can also be said that the optical element 20 divides the optical path of the imaging optical system 10 into an optical path on the image plane 210 side of the imaging optical system 10 (an optical path from the optical element 20 to the image plane 210 when viewed from the object side) and an optical path on the conjugate plane 220 side of the imaging optical system 10 (an optical path from the optical element 20 to the conjugate plane 220 when viewed from the object side). The optical member 20, for example, emits light from the imaging optical system 10 along an optical path on the image plane 210 side to form a reduced image of at least a portion of an object on the image plane 210. The optical member 20 also receives light (illumination beam 51) for optical wireless communication emitted from the light transmitting and receiving optical element 41 along an optical path on the conjugate plane 220 side, and emits the light toward the imaging optical system 10. Here, for example, the light transmitting and receiving optical element 41 is disposed near the conjugate plane 220. In other words, it can be said that the optical member 20 emits light (illumination beam 51) from the light transmitting and receiving optical element 41 (i.e., the light generating device 60) that enters through the conjugate plane 220 toward the imaging optical system 10. Incidentally, even when the light emitting end 223 of the light transmitting and receiving optical element 41 is disposed on the conjugate plane 220 or when the light emitting end 223 is disposed slightly closer to the optical member 20 than the conjugate plane 220, the optical member 20 is considered to emit light (illumination beam 51) from the light transmitting and receiving optical element 41 (i.e., the light generating device 60) incident via the conjugate plane 220 toward the imaging optical system 10. Furthermore, the optical member 20 emits light (illumination beam 51) for optical wireless communication incident via the imaging optical system 10 along the optical path on the conjugate plane 220 side (toward the light transmitting and receiving optical element 41).

[0032] The optical member 20 may be, for example, a half mirror. In this case, the optical member 20 transmits approximately 50% of the light from the imaging optical system 10 for forming a reduced image of at least a portion of an object on the image plane 210 and emits the light along an optical path on the image plane 210 side. The optical member 20 also reflects approximately 50% of the light (illumination beam 51) for optical wireless communication that is emitted from the light transmitting and receiving optical element 41 along an optical path on the conjugate plane 220 side and emits the light toward the imaging optical system 10. The optical member 20 also reflects approximately 50% of the light (illumination beam 51) for optical wireless communication that is incident via the imaging optical system 10 and emits the light along the optical path on the conjugate plane 220 side (toward the light transmitting and receiving optical element 41).

[0033] The optical element 20 is not limited to a half mirror. The optical element 20 may be a reflective element having a reflectance other than 50%. The optical element 20 may also be a dichroic mirror. In this case, the wavelengths of the respective lights may be determined so that the light (illumination beam 51) for optical wireless communication is reflected by the dichroic mirror, and the light from the imaging optical system 10 for forming a reduced image of at least a portion of the object on the image plane 210 is transmitted. The optical element 20 may also be a polarizing beam splitter. The optical element 20 may also be called a beam splitter because it splits the optical path.

[0034] The conjugate surface 220 is a surface that is located on the opposite side of the imaging optical system 10 from the object side (the image plane 210 side) and is conjugate with the image plane 210. That is, in the imaging optical system 10, the image plane 210 and the conjugate surface 220 are conjugate. The image plane 210 may be referred to as the first conjugate surface, and the conjugate surface 220 may be referred to as the second conjugate surface. The negative x-axis direction side of the imaging optical system 10 may be referred to as the object side, and the positive x-axis direction side may be referred to as the image plane 210 side or the conjugate surface 220 side.

[0035] In this embodiment, the x-axis side of the optical element 20 is described as the image plane 210, and the y-axis side of the optical element 20 is described as the conjugate plane 220. However, the image plane 210 and the conjugate plane 220 may be configured in reverse. That is, the y-axis side of the optical element 20 may be the image plane 210, and the x-axis side of the optical element 20 may be the conjugate plane 220.

[0036] The position changing device 40 changes the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10. Specifically, the position changing device 40 may include a drive unit for changing the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220. The position changing device 40 may be a drive device for changing the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220. The position changing device 40 changes the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 by changing the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220. Note that when the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220 changes, the position at which the irradiation beam 51 enters the imaging optical system 10 via the optical element 20 changes. As the incident position of the irradiation beam 51 from the optical element 20 to the imaging optical system 10 changes, the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 changes. It can also be said that the position changing device 40 changes the irradiation direction of the irradiation beam 51 emitted from the imaging optical system 10 by changing the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220 .

[0037] The position changing device 40 may be a drive device that moves at least one of the light transmitting and receiving optical element 41, the optical member 20, the imaging optical system 10, and the imaging device 30. The position changing device 40 may be a drive device that moves the light transmitting and receiving optical element 41 relative to the optical member 20, the imaging optical system 10, and the imaging device 30. In this case, the position changing device 40 may be a well-known drive device such as a linear motor or a stepping motor that can move the light transmitting and receiving optical element 41. Note that the position changing device 40 may be a drive device that moves the optical member 20, the imaging optical system 10, and the imaging device 30 relative to the light transmitting and receiving optical element 41.

[0038] For example, the position changing device 40 may move the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111 of the imaging optical system 10 (e.g., the direction of arrow 410 shown in FIG. 2 or the x-axis or z-axis direction). For example, if the imaging optical system 10 is configured to be image-side telecentric, the position changing device 40 can also be expressed as moving the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111 on the light transmitting and receiving optical element 41 side of the imaging optical system 10. "Moving the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111 of the imaging optical system 10" may be a direction perpendicular to the optical axis 411, or a direction intersecting at an angle other than a right angle. Alternatively, the position changing device 40 can be expressed as moving the light transmitting and receiving optical element 41 in a direction parallel to the conjugate plane 220. Here, the optical axis 111 of the imaging optical system 10 may be referred to as the optical axis 111a from the optical member 20 to the conjugate plane 220, and the optical axis 111b from the optical member 20 to the image plane 210. The optical axis 111a may also be referred to as the optical axis on the conjugate plane 220 side of the imaging optical system 10. The optical axis 111b may also be referred to as the optical axis on the image plane 210 side of the imaging optical system 10. In this case, the position changing device 40 can also be said to move the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111a. The position changing device 40 can also be said to move the light transmitting and receiving optical element 41 in a direction perpendicular to the optical axis 111a. The position changing device 40 can also be said to change the position of the light transmitting and receiving optical element 41 on the plane intersecting the optical axis 111a. It can also be said that the position changing device 40 changes the position of the light transmitting and receiving optical element 41 in a plane perpendicular to the optical axis 111a. The position changing device 40 may change the position of the irradiation beam 51 from the light generating device 60 (light transmitting and receiving optical element 41) on the conjugate plane 220 by moving the light transmitting and receiving optical element 41 as described above. Note that the position changing device 40 is not limited to the light transmitting and receiving optical element 41, and may also change the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220 by moving the entire light generating device 60 as described above. Note that, as described above, since the light transmitting and receiving optical element 41 can be considered a light emitting portion, the optical axis 111a may also be referred to as the optical axis on the light emitting portion side of the imaging optical system 10. Also, as described above, since the light transmitting and receiving optical element 41 can be considered a light receiving portion, the optical axis 111a may also be referred to as the optical axis on the light receiving portion side of the imaging optical system 10.As described above, since the light transmitting and receiving optical element 41 can be regarded as a light transmitting and receiving section, the optical axis 111a may be referred to as the optical axis of the imaging optical system 10 on the light transmitting and receiving section side.

[0039] The position changing device 40 moves the irradiation position of the irradiation beam 51 in the direction of the arrow 110, for example, by moving the light transmitting and receiving optical element 41 in the direction of the arrow 410. The position changing device 40 also changes the light receiving position of the light (irradiation beam 51) for optical wireless communication emitted from the other light emitting device 1 in the optical wireless communication. The light receiving position may also be referred to as the position where the light (irradiation beam 51) from the other light emitting device 1 in the optical wireless communication is incident on the imaging optical system 10. The light receiving position may also be referred to as the position of the light transmitting and receiving optical element 41 in a direction perpendicular to the optical axis 111a. For example, the position changing device 40 changes the light receiving position of the light (irradiation beam 51) for optical wireless communication by moving the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a as described above. When the position changing device 40 moves the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111a, the optical path from the imaging optical system 10 to the light transmitting and receiving optical element 41 changes. Changing the optical path from the imaging optical system 10 to the light transmitting and receiving optical element 41 changes the light receiving position of the light (illumination beam 51) for optical wireless communication. The position changing device 40 may also move the light transmitting and receiving optical element 41 in a direction perpendicular to the optical axis 111a. The position changing device 40 may also change the position of the light transmitting and receiving optical element 41 on a plane intersecting the optical axis 111a. The position changing device 40 may also change the position of the light transmitting and receiving optical element 41 on a plane perpendicular to the optical axis 111a. The position changing device 40 may change the light receiving position of the light (illumination beam 51) for optical wireless communication by moving the light transmitting and receiving optical element 41 as described above. The position changing device 40 may change the light receiving position of the light (illumination beam 51) for optical wireless communication by moving the entire light generating device 60 as described above. It can also be said that the position changing device 40 changes the light receiving direction of the light (illumination beam 51) for optical wireless communication by moving the light transmitting and receiving optical element 41 as described above.

[0040] The position changing device 40 may move the optical member 20 relative to the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111a of the imaging optical system 10. Even in this case, it can be said that the position changing device 40 changes the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220. It can also be said that the position changing device 40 moves the optical member 20, the imaging optical system 10, and the imaging device 30 together relative to the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111a of the imaging optical system 10. It can also be said that the position changing device 40 moves the light transmitting and receiving optical element 41 and the optical member 20 individually in a direction intersecting the optical axis 111a of the imaging optical system 10. Even in this case, it can be said that the position changing device 40 changes the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220. The position changing device 40 may move the optical member 20, the imaging optical system 10, and the image capturing device 30 together in a direction intersecting the optical axis 111 a of the imaging optical system 10.

[0041] The control device 50 controls the imaging device 30 so that the imaging device 30 captures at least a portion of an image of the object. The control device 50 also controls the position changing device 40 based on the imaging result of the imaging device 30. It can also be said that the control device 50 moves the light transmitting and receiving optical element 41 using the position changing device 40 based on the imaging result of the imaging device 30. The control device 50 controls the position changing device 40 based on the position of at least a portion of the object on the image acquired by imaging by the imaging device 30 so that the irradiation beam 51 emitted from the imaging optical system 10 is incident on the imaging optical system 10 of the other light irradiation device 1 that is communicating with the optical wireless communication (i.e., so that the irradiation position of the irradiation beam 51 is the imaging optical system 10 of the other light irradiation device 1).

[0042] Here, a correspondence may be established in advance between the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a (i.e., the position on the conjugate plane 220 of the irradiation beam 51) and the position on the image acquired by the imaging device 30. For example, by establishing a correspondence between the position on the image acquired by the imaging device 30 and the irradiation position of the irradiation beam 51, a correspondence may be established between the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a and the position on the image acquired by the imaging device 30. As described above, the irradiation position of the irradiation beam 51 is determined by the position on the conjugate plane 220 of the irradiation beam 51 from the light generating device 60, i.e., the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a. Therefore, by establishing a correspondence between the position on the image acquired by the imaging device 30 and the irradiation position of the irradiation beam 51, a correspondence may be established between the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a and the position on the image acquired by the imaging device 30. The method of association will be described later.

[0043] By associating the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a with the position on the image acquired by the imaging device 30, it is possible to more accurately irradiate the irradiation beam 51 to the target position of the object recognized on the image acquired by the imaging device 30. Therefore, by controlling the position changing device 40 based on the position of at least a part of the object on the image acquired by the imaging device 30, the control device 50 can more accurately make the irradiation beam 51 emitted from the imaging optical system 10 incident on the imaging optical system 10 of the other light irradiation device 1 in the optical wireless communication.

[0044] Note that the position on the image acquired by the imaging device 30 may be referred to as the position on the imaging surface of the imaging element 31 of the imaging device 30, or may be referred to as the pixel position of the imaging element 31. For example, the control device 50A may control the position changing device 40A (may move the light transmitting and receiving optical element 41A) so that the irradiation beam 51 emitted from the imaging optical system 10A is incident on the imaging optical system 10B (i.e., so that the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10A is the imaging optical system 10B) based on the position of at least a part of the light irradiation device 1B as an object on the image acquired by imaging by the imaging device 30A.

[0045] The control device 50 may control the position change device 40 based on a characteristic part of the object detected based on the imaging result captured by the imaging device 30. The characteristic part of the object may be at least a part of the object. The characteristic part of the object may be a marker arranged on the other light irradiation device 1 that is to communicate with the optical wireless communication. In this case, the positional relationship between the marker arranged on the other light irradiation device 1 that is to communicate with the optical wireless communication and the target position to which the irradiation beam 51 of the other light irradiation device 1 is to be irradiated (for example, the imaging optical system 10 of the other light irradiation device 1) may be known.

[0046] The marker as the characteristic location of the object may be a well-known marker such as a one-dimensional barcode, a QR code (registered trademark), or an AR marker provided on the light irradiation device 1 of the other party in the optical wireless communication. The marker as the characteristic location of the object may be a location illuminated by a light-emitting unit such as an LED provided on the light irradiation device 1 of the other party in the optical wireless communication, or may be a blinking pattern of the light-emitting unit. The light-emitting unit is not limited to an LED and may be another existing light-emitting element or a light-emitting device composed of multiple light-emitting elements. The blinking pattern of the light-emitting unit may be a pattern based on a specific rule, such as Morse code. The blinking pattern of the light-emitting unit may change depending on the position of the light-emitting unit in the direction intersecting the optical axis 111a of the light-transmitting and receiving optical element 41 of the other party's light irradiation device 1 in which the light-emitting unit is provided. For example, at least one of the blinking period of the light-emitting unit and the light emission intensity when lit may be changed (i.e., the blinking pattern may be changed) depending on the position of the light-emitting unit in the direction intersecting the optical axis 111a of the light-transmitting and receiving optical element 41 of the other party's light irradiation device 1 in which the light-emitting unit is provided. Note that a predetermined blinking pattern of the light-emitting unit (e.g., at least one of a predetermined blinking cycle and a predetermined light emission intensity) may be referred to as the state of the marker. A change in the blinking pattern of the light-emitting unit may be referred to as a change in the state of the marker.

[0047] Furthermore, the marker as the characteristic location of the object may be a marker displayed on a display unit provided on the other light irradiation device 1 in optical wireless communication. The marker displayed on the display unit may be a well-known marker such as a one-dimensional barcode, a QR code (registered trademark), or an AR marker. The marker displayed on the display unit may change depending on the position in a direction intersecting with the optical axis 111a of the light transmitting and receiving optical element 41 of the other light irradiation device 1 in which the display unit is provided. For example, at least one of the shape and color of the marker displayed on the display unit may be changed depending on the position in a direction intersecting with the optical axis 111a of the light transmitting and receiving optical element 41 of the other light irradiation device 1 in which the display unit is provided (i.e., the marker displayed on the display unit may be changed). The display unit may be an existing display such as a liquid crystal display. The display state of the display unit (e.g., at least one of the shape and color of a specified marker) may be referred to as the state of the marker. A change in the display state of the display unit (e.g., a change in at least one of the shape and color of a marker) may be referred to as the change in the state of the marker. The markers as characteristic portions of the object may be any known markers as long as they can be recognized on the image acquired by the imaging device 30 .

[0048] Furthermore, the characteristic portion of the object may be at least one of an edge, a contour, and a texture of at least a part of the other light irradiation device 1 in the optical wireless communication. In this case, the positional relationship between at least one of the edge, a contour, and a texture of at least a part of the other light irradiation device 1 in the optical wireless communication and a target position to which the irradiation beam 51 of the other light irradiation device 1 is irradiated may be known.

[0049] The characteristic part of the object may be at least a part of the imaging optical system 10 of the light irradiation device 1, which is the other party in the optical wireless communication. In this case, at least a part of the imaging optical system 10 may be at least a part of the optical element closest to the object among the plurality of optical elements constituting the imaging optical system 10 (i.e., at least a part of the optical element arranged farthest from the image capture device 30 among the plurality of optical elements constituting the imaging optical system 10). The characteristic part of the object may be at least a part of a protective member covering the object side of the imaging optical system 10 of the light irradiation device 1, which is the other party in the optical wireless communication. The protective member covering the object side of the imaging optical system 10 can be considered to be part of the imaging optical system 10. This protective member may be a light-transmitting member that transmits light (irradiation beam 51) for performing the optical wireless communication.

[0050] The control device 50 may identify the position of at least a portion of an object on an image acquired by the imaging device 30 through image processing using a template matching method, an active search method, a mean shift method, a particle filter method, or the like. Identifying the Position of a Feature Location. The control device 50 may identify the position of at least a portion of an object on an image acquired by the imaging device 30 through image processing using machine learning such as deep learning. In this case, an inference device (which may also be referred to as an inference model) that receives an acquired image and outputs the position on the image of at least a portion of the object to be identified may be generated in advance using machine learning. The control device 50 may input the image acquired by the imaging device 30 into the inference device and acquire the position of at least a portion of the object on the image output from the inference device, thereby identifying the position of at least a portion of the object on the image. The position of at least a portion of the object on the image acquired by the imaging device 30 identified by the control device 50 through the above-described image processing may be the position of a feature location of the object on the image.

[0051] Based on the position of the identified characteristic location on the image, the control device 50 moves the light transmitting and receiving optical element 41 so that the irradiation beam 51 emitted from the imaging optical system 10 is incident on the other light irradiation device 1 that is communicating with the optical wireless communication. The light transmitting and receiving optical element 41 transmits light (irradiation beam 51) at the position after the movement, thereby irradiating the irradiation beam 51 to the other light irradiation device 1 that is communicating with the optical wireless communication.

[0052] For example, the above-described image processing is used to identify the position of a marker provided on the other party's light irradiation device 1 on the image acquired by the imaging device 30. Based on the identified position of the marker on the image and the positional relationship between the marker and the imaging optical system 10 of the other party's light irradiation device 1, which is the target of irradiation with the irradiation beam 51, the control device 50 may control the position changing device 40 (or move the light transmitting and receiving optical element 41) so that the irradiation beam 51 emitted from the light irradiation device 1 is incident on the imaging optical system 10 of the other party's light irradiation device 1.

[0053] In this case, the position of the light transmitting and receiving optical element 41 of the other light irradiation device 1 in a direction intersecting the optical axis 111a may be determined in advance so that the irradiation beam 51 incident on a specific position of the imaging optical system 10 of the other light irradiation device 1 is incident on the light transmitting and receiving optical element 41 of the other light irradiation device 1. Here, the light incident on the specific position of the imaging optical system 10 of the light irradiation device 1 travels along a specific optical path and is incident on a specific position of the conjugate plane 220 via the optical member 20. In other words, the incident position of the light on the conjugate plane 220 is determined by the incident position of the light on the imaging optical system 10 of the light irradiation device 1. Therefore, when the light transmitting and receiving optical element 41 is positioned so that the light incident on the specific position of the conjugate plane 220 is incident on the light transmitting and receiving optical element 41, the light incident on the specific position of the imaging optical system 10 can be received by the light transmitting and receiving optical element 41. The control device 50 may control the position changing device 40 so that the irradiation beam 51 emitted from the light irradiation device 1 is incident on a specific position of the imaging optical system 10 of the other party's light irradiation device 1 (i.e., the light transmitting and receiving optical element 41 of the other party's light irradiation device 1) based on the position on the image of the marker provided on the other party's light irradiation device 1, the positional relationship between the imaging optical system 10 of the other party's light irradiation device 1 and the marker, and a specific position of the imaging optical system 10 of the other party's light irradiation device 1 at which the irradiation beam 51 is incident. Note that the specific position of the imaging optical system 10 of the other party's light irradiation device 1 may be the center of the optical element closest to the object among the multiple optical elements constituting the imaging optical system 10, or may be a position a known distance away from the center.

[0054] Furthermore, the control device 50 may detect the state of the marker of the other light irradiation device 1 based on the imaging result of the imaging device 30, and based on the detected state of the marker, identify the position in the direction intersecting with the optical axis 111a of the light transmitting and receiving optical element 41 of the other light irradiation device 1. Here, if the position in the direction intersecting with the optical axis 111a of the light transmitting and receiving optical element 41 of the other light irradiation device 1 can be identified, the incident position on the imaging optical system 10 of the other light irradiation device 1 for making the irradiation beam 51 incident on the light transmitting and receiving optical element 41 can be identified. Therefore, the control device 50 may control the position changing device 40 so that the irradiation beam 51 emitted from the light irradiation device 1 is incident on the light transmitting and receiving optical element 41 of the other light irradiation device 1, based on the position of the marker of the other light irradiation device 1 on the image acquired by the imaging device 30, which is specified by the above-mentioned image processing, the positional relationship between the marker and the imaging optical system 10 of the other light irradiation device 1, and the incident position on the imaging optical system 10 of the other light irradiation device 1, which is specified based on the state of the detected marker. Note that the relationship between the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a of the other light irradiation device 1 and the incident position on the imaging optical system 10 of the other light irradiation device 1 for making the irradiation beam 51 incident on the light transmitting and receiving optical element 41 may be determined in advance. When detecting the blinking pattern of the light-emitting unit (for example, at least one of the blinking cycle and the light emission intensity when lit) as the state of the marker provided in the other party's light irradiation device 1, the control device 50 may detect the blinking pattern of the light-emitting unit based on multiple images (i.e., multiple images captured at different times) acquired by the imaging device 30 at a predetermined frame rate. When detecting the display state of the display unit (for example, at least one of the shape of the marker and the color of a predetermined marker) as the state of the marker, the control device 50 may detect the display state of the display unit based on images acquired by the imaging device 30.

[0055] For example, as described above, the control device 50A of the light irradiation device 1A may control the position changing device 40A so that the irradiation beam 51 emitted from the light irradiation device 1A is incident on the imaging optical system 10B, based on the position of the marker of the light irradiation device 1B on the image acquired by the imaging device 30A, which is identified by the image processing described above. Here, as described above, the positional relationship between the marker and the imaging optical system 10, which is the target to which the irradiation beam 51 is emitted, may be known. The control device 50A may control the position changing device 40A so that the irradiation beam 51 emitted from the light irradiation device 1A is incident on the light transmitting and receiving optical element 41B (i.e., the communication board 62B) via the imaging optical system 10B, based on the position of the marker of the light irradiation device 1B on the image and the positional relationship between the marker and the imaging optical system 10B, which is the target to which the irradiation beam 51 is emitted. The control device 50B of the light irradiation device 1B may control the position changing device 40B (move the light transmitting and receiving optical element 41B) so that the irradiation beam 51 from the light irradiation device 1A, which has entered the imaging optical system 10B, is incident on the light transmitting and receiving optical element 41B. For example, the control device 50B may control the position changing device 40B so that the irradiation beam 51 from the light irradiation device 1A, which has entered the imaging optical system 10B, is incident on the light transmitting and receiving optical element 41B, based on the position of the marker of the light irradiation device 1A on the image acquired by the imaging device 30B, which is identified by the image processing described above. In this case, the control device 50B is not limited to irradiating the irradiation beam 51 from the light irradiation device 1A, but may also irradiate the irradiation beam 51 so that it is incident on the light transmitting and receiving optical element 41A (i.e., the communication board 62A) of the light irradiation device 1A.

[0056] The control device 50B of the light irradiation device 1B may control the position changing device 40B so that the irradiation beam 51 emitted from the light irradiation device 1B is incident on the imaging optical system 10A, based on the position of the marker of the light irradiation device 1A on the image acquired by the imaging device 30B, which is identified by the image processing described above. Here, as described above, the positional relationship between the marker and the imaging optical system 10A, which is the target to which the irradiation beam 51 is emitted, may be known. The control device 50B may control the position changing device 40B so that the irradiation beam 51 emitted from the light irradiation device 1B is incident on the light transmitting and receiving optical element 41A (i.e., the communication board 62A) via the imaging optical system 10A, based on the position of the marker of the light irradiation device 1A on the image and the positional relationship between the marker and the imaging optical system 10A, which is the target to which the irradiation beam 51 is emitted. The control device 50A of the light irradiation device 1A may control the position changing device 40A so that the irradiation beam 51 from the light irradiation device 1B, which has entered the imaging optical system 10A, is incident on the light transmitting and receiving optical element 41A. For example, the control device 50A may control the position changing device 40A so that the irradiation beam 51 from the light irradiation device 1B, which has entered the imaging optical system 10A, is incident on the light transmitting and receiving optical element 41A, based on the position of the marker of the light irradiation device 1B on the image acquired by the imaging device 30A, which is identified by the image processing described above. In this case, the control device 50A is not limited to irradiating the irradiation beam 51 from the light irradiation device 1B, but may also irradiate the irradiation beam 51 so that it is incident on the light transmitting and receiving optical element 41B (i.e., the communication board 62B) of the light irradiation device 1B.

[0057] Furthermore, when the irradiation beam 51 from the light irradiation device 1A is incident on the light transmitting and receiving optical element 41B through the imaging optical system 10B and the light transmitting and receiving optical element 41A is stopped in a direction intersecting with the optical axis 111a of the light irradiation device 1A, and the light transmitting and receiving optical element 41B is stopped in a direction intersecting with the optical axis 111a of the light irradiation device 1B, the irradiation beam 51 from the light transmitting and receiving optical element 41B is emitted through an optical path similar to the optical path taken by the irradiation beam 51 from the light irradiation device 1A incident from the imaging optical system 10B through the optical member 20B and the conjugate surface 220 until it is received by the light transmitting and receiving optical element 41B. Therefore, when the control device 50A controls the position changing device 40A so that the irradiation beam 51 emitted from the light irradiation device 1A passes through the imaging optical system 10B and is incident on the light transmitting and receiving optical element 41B, the control device 50B does not need to control the position changing device 40B (i.e., the control device 50B does not need to move the light transmitting and receiving optical element 41B in a state where the irradiation beam 51 from the light irradiation device 1A is incident on the light transmitting and receiving optical element 41B), and the irradiation beam 51 emitted from the light irradiation device 1B is incident on the light transmitting and receiving optical element 41A. Conversely, when the control device 50B controls the position changing device 40B so that the irradiation beam 51 emitted from the light irradiation device 1B passes through the imaging optical system 10A and is incident on the light transmitting and receiving optical element 41B, the control device 50A does not need to control the position changing device 40A, and the irradiation beam 51 emitted from the light irradiation device 1A is incident on the light transmitting and receiving optical element 41B.

[0058] The control device 50B may determine the position of the light transmitting and receiving optical element 41B onto which the irradiation beam 51 from the light irradiation device 1A is incident after entering the imaging optical system 10B, without using the imaging result of the imaging device 30B. For example, the control device 50B may determine the position of the light transmitting and receiving optical element 41B by controlling the position changing device 40B to move the light transmitting and receiving optical element 41B and detecting the reception state of the irradiation beam 51 at the communication board 62B. In this case, the position of the light transmitting and receiving optical element 41B in the direction intersecting the optical axis 111a of the light irradiation device 1B may be the position when the control device 50B detects that the communication board 62B has received the irradiation beam 51 from the light irradiation device 1A. In this case, the control device 50A may irradiate the irradiation beam 51 to the light transmitting and receiving optical element 41B while the control device 50B irradiates the irradiation beam 51 to the light transmitting and receiving optical element 41A. The control device 50A may determine the position at which the irradiation beam 51 from the light irradiation device 1B, which has entered the imaging optical system 10A, is incident on the light transmitting and receiving optical element 41A, without using the imaging result of the imaging device 30A. For example, the control device 50A may determine the position of the light transmitting and receiving optical element 41A by controlling the position changing device 40A to move the light transmitting and receiving optical element 41A and detecting the reception state of the irradiation beam 51 at the communication board 62A. In this case, the position of the light transmitting and receiving optical element 41A in the direction intersecting the optical axis 111a of the light irradiation device 1A may be the position at which the control device 50A detects that the communication board 62A has received the irradiation beam 51 from the light irradiation device 1B. In this case, the control device 50B may irradiate the irradiation beam 51 to the light transmitting and receiving optical element 41B while irradiating the irradiation beam 51 to the light transmitting and receiving optical element 41A.

[0059] As described above, the control device 50A may control the position changing device 40A so that the irradiation beam 51 from the light irradiation device 1A is incident on a specific position of the imaging optical system 10B in a state where the position of the light transmitting and receiving optical element 41B in a direction intersecting the optical axis 111a of the light irradiation device 1B is positioned at a specific position so that the irradiation beam 51 incident on a specific position of the imaging optical system 10B of the light irradiation device 1B is incident on the light transmitting and receiving optical element 41B. In this case, the control device 50A may control the position changing device 40A so that the irradiation beam 51 emitted from the light irradiation device 1A is incident on a specific position of the imaging optical system 10B (i.e., the light transmitting and receiving optical element 41B) based on the position on the image of a marker provided on the light irradiation device 1B, the positional relationship between the imaging optical system 10B and the marker, and the specific position of the imaging optical system 10B on which the irradiation beam 51 is incident. The control device 50B may control the position changing device 40B so that the light transmitting and receiving optical element 41B is positioned at a specific position in a direction intersecting the optical axis 111a of the light irradiation device 1B. In this case, the control device 50B may irradiate the irradiation beam 51. The irradiation beam 51 emitted from the light irradiation device 1B is incident on the light transmitting and receiving optical element 41A of the light irradiation device 1A.

[0060] Similarly, the control device 50B may control the position changing device 40B so that the irradiation beam 51 from the light irradiation device 1B is incident on a specific position of the imaging optical system 10A in a state where the position of the light transmitting and receiving optical element 41A in a direction intersecting the optical axis 111a of the light irradiation device 1A is positioned at a specific position so that the irradiation beam 51 incident on a specific position of the imaging optical system 10A is incident on the light transmitting and receiving optical element 41A. In this case, the control device 50A may irradiate the irradiation beam 51. The irradiation beam 51 emitted from the light irradiation device 1A is incident on the light transmitting and receiving optical element 41B.

[0061] The control device 50A may determine the position of the light-emitting element 41B of the light irradiation device 1B in a direction intersecting the optical axis 111a based on the blinking pattern of the light-emitting element serving as a marker provided on the light irradiation device 1B, detected by the image processing described above. For example, the control device 50A may control the position changing device 40A so that the irradiation beam 51 emitted from the light irradiation device 1A is incident on the light-transmitting and receiving optical element 41B of the light irradiation device 1B based on the position of the light-emitting element of the light irradiation device 1B on the image acquired by the imaging device 30A, determined by the image processing described above, the positional relationship between the imaging optical system 10B and the light-emitting element of the light irradiation device 1B, and the incident position on the imaging optical system 10B, determined based on the detected blinking pattern of the light-emitting element. In this case, the control device 50B may irradiate the irradiation beam 51. The irradiation beam 51 emitted from the light irradiation device 1B is incident on the light-transmitting and receiving optical element 41A of the light irradiation device 1A. Furthermore, the relationship between the position of the light transmitting and receiving optical element 41B in the light irradiation device 1B in the direction intersecting the optical axis 111a and the incident position into the imaging optical system 10B for making the irradiation beam 51 incident on the light transmitting and receiving optical element 41B may be determined in advance.

[0062] The control device 50A may control the position changing device 40A so that the irradiation beam 51 emitted from the light irradiation device 1A is incident on the light transmitting and receiving optical element 41B, based on the position of at least one of the edges, contours, and textures of at least a part of the light irradiation device 1B on the image acquired by the imaging device 30A, which position is specified by the image processing described above. In this case, the control device 50A may control the position changing device 40A so that the irradiation beam 51 emitted from the light irradiation device 1A is incident on the light transmitting and receiving optical element 41B, based on the position of at least one of the edges, contours, and textures of at least a part of the light irradiation device 1B on the image acquired by the imaging device 30A and the positional relationship between the imaging optical system 10B and at least one of the edges, contours, and textures of the light irradiation device 1B.

[0063] At this time, the control device 50B may move the light-transmitting and receiving optical element 41B so that the irradiation beam 51 from the light irradiation device 1A incident on the imaging optical system 10B is incident on the light-transmitting and receiving optical element 41B. In this case, the control device 50B may control the position changing device 40B so that the irradiation beam 51 from the light irradiation device 1A incident on the imaging optical system 10B is incident on the light-transmitting and receiving optical element 41B based on the position of at least one of the edges, contours, and textures of at least a portion of the light irradiation device 1A on the image acquired by the imaging device 30B, which is identified by the image processing described above, and the positional relationship between the at least one of the edges, contours, and textures of the light irradiation device 1A and the imaging optical system 10A. Note that the control device 50B may irradiate the irradiation beam 51 while the irradiation beam 51 from the light irradiation device 1A is incident on the light-transmitting and receiving optical element 41B. The irradiation beam 51 emitted from the light irradiation device 1B is incident on the light-transmitting and receiving optical element 41A. As described above, at least a part of the object on the image whose position is identified by the image processing of the control device 50 described above may be different from at least a part of the object illuminated by the light illumination device 1 .

[0064] The control device 50A may control the position changing device 40A so that the irradiation beam 51 emitted from the light irradiation device 1A is incident on the imaging optical system 10B (the optical member closest to the object) based on the position of the optical member closest to the object in the imaging optical system 10B on the image acquired by the imaging device 30A, which position is determined by the image processing described above. In this case, the control device 50B may control the position changing device 40B so that the irradiation beam 51 from the light irradiation device 1A that has entered the imaging optical system 10B is incident on the light transmitting and receiving optical element 41B. The control device 50B may also irradiate the irradiation beam 51 while the irradiation beam 51 from the light irradiation device 1A is incident on the light transmitting and receiving optical element 41B. The irradiation beam 51 emitted from the light irradiation device 1B is incident on the light transmitting and receiving optical element 41A. Furthermore, the control device 50 is not limited to determining the position of the characteristic part of the object on the image acquired by the imaging device 30, but may also use the above-mentioned image processing to identify at least one of the position and orientation of the characteristic part of the object in real space based on the brightness distribution of the image acquired by the imaging device 30, and control the position changing device 40 based on the identified at least one of the position and orientation of the object in real space so that the irradiation beam 51 emitted from the imaging optical system 10 is incident on the light transmitting and receiving optical element 41 of the light irradiation device 1 of the other party in the optical wireless communication.

[0065] Here, the effects of each element of the light irradiation device 1 on the irradiation beam 51 during light transmission will be described. First, the irradiation beam 51 is generated by the light generating device 60. The irradiation beam 51 emitted from the light transmitting and receiving optical element 41 is incident on the optical member 20 from the conjugate plane 220. The optical member 20 changes the traveling direction of the incident irradiation beam 51 (for example, if the optical member 20 is a half mirror, it reflects the irradiation beam 51), and emits it toward the imaging optical system 10. The imaging optical system 10 emits the incident irradiation beam 51 toward the other light irradiation device 1, which is an example of an object.

[0066] Next, the action of each element of the light irradiation device 1 on the irradiation beam 51 when it is received will be described. First, the irradiation beam 51 irradiated from the other light irradiation device 1, which is an example of an object, is incident on the imaging optical system 10. The imaging optical system 10 emits the incident irradiation beam 51 toward the optical element 20. The optical element 20 changes the traveling direction of the incident irradiation beam 51 (for example, if the optical element 20 is a half mirror, it reflects the irradiation beam 51), and emits it toward the light transmitting and receiving optical element 41 via the conjugate surface 220. The irradiation beam 51 incident on the light transmitting and receiving optical element 41 is received by the communication board 62 via the optical fiber 61.

[0067] Next, the effects of each element provided in the light irradiation device 1 on light for forming a reduced image of at least a portion of an object on the image plane 210 will be described. Light for forming a reduced image of at least a portion of the other light irradiation device 1, which is an example of an object, on the image plane 210 is incident on the imaging optical system 10. The imaging optical system 10 forms a reduced image of at least a portion (for example, the characteristic location described above) of the other light irradiation device 1 on the image plane 210 via the optical member 20. The reduced image formed on the image plane 210 is captured by the imaging device 30.

[0068] In the present embodiment, the optical element 20 is disposed closer to the light generating device 60 than the imaging optical system 10, but the position of the optical element 20 is not limited to this example. The optical element 20 may be disposed, for example, within the imaging optical system 10, in other words, between a plurality of optical elements (a plurality of optical elements different from the optical element 20) that constitute the imaging optical system 10. Specifically, the optical element 20 may be disposed between at least one optical element of the imaging optical system 10 that is disposed on the object side with respect to the optical element 20 and at least one optical element of the imaging optical system 10 that is disposed on the image plane 210 side with respect to the optical element 20.

[0069] The optical element 20 may emit light that has passed through at least a portion of the imaging optical system 10 toward the image plane of the imaging optical system 10. The optical element 20 may emit light that has entered through at least one optical element of the imaging optical system 10 that is arranged on the object side of the optical element 20 toward at least one optical element of the imaging optical system 10 that is arranged on the image plane 210 side of the optical element 20. The light that has been emitted toward at least one optical element of the imaging optical system 10 that is arranged on the image plane 210 side of the optical element 20 may be emitted toward the image plane 210. Therefore, it can also be said that the optical element 20 emits light that has passed through at least a portion of the imaging optical system 10 toward the image plane of the imaging optical system 10. The optical element 20 may also emit light that has entered through at least one optical element of the imaging optical system 10 that is arranged on the object side of the optical element 20 toward the light generating device 60 (light transmitting and receiving optical element 41). Furthermore, the optical element 20 may emit the irradiation beam 51 from the light generating device 60 toward at least a portion of the imaging optical system 10. The optical element 20 may emit the irradiation beam 51 from the light generating device 60, which has been incident on the optical element 20, toward at least one optical element of the imaging optical system 10 that is arranged on the object side with respect to the optical element 20. The irradiation beam 51 emitted toward at least one optical element of the imaging optical system 10 that is arranged on the object side with respect to the optical element 20 may be emitted toward the object. Therefore, it can also be said that the optical element 20 emits the irradiation beam 51 from the light generating device 60 toward at least a portion of the imaging optical system 10. Note that the optical element 20 may be arranged on the object side of the imaging optical system 10. In this case, the imaging device 30 captures at least a portion of the image of the object formed on the image plane 210 by the imaging optical system 10. Furthermore, the position changing device 40 changes the incident position of the irradiation beam 51 from the light generating device 60 on the optical member 20, thereby changing the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10. The light irradiation device 1 irradiates at least a part of the object with the irradiation beam 51 emitted from the imaging optical system 10, based on the imaging result of the imaging device 30.

[0070] Since the optical element 20 may affect the state of the image formed on the image plane 210, it may also be considered to be part of the imaging optical system 10. The optical element 20 may also be considered to be included in the imaging optical system 10. In the light irradiation device 1, the optical element 20 may also be considered to be provided in the imaging optical system 10. In this case, the light irradiation device 1 may also be considered to include the imaging optical system 10, the imaging device 30, and the position changing device 40. The optical element 20 of the imaging optical system 10 may emit incident light toward the image plane 210. The optical element 20 may emit light incident through at least one optical element of the imaging optical system 10 that is arranged on the object side with respect to the optical element 20, toward at least one optical element of the imaging optical system 10 that is arranged on the image plane 210 side with respect to the optical element 20. Furthermore, light emitted toward at least one optical element of the imaging optical system 10 that is arranged on the image plane 210 side with respect to the optical element 20 may be emitted toward the image plane 210. Therefore, it can also be said that the optical element 20 of the imaging optical system 10 emits light incident on the optical element 20 toward the image plane 210. Furthermore, the optical element 20 may emit light that is incident via at least one optical element of the imaging optical system 10 that is arranged on the object side with respect to the optical element 20, toward the light generating device 60 (light transmitting / receiving optical element 41). Furthermore, the optical element 20 of the imaging optical system 10 may emit the irradiation beam 51 from the light generating device 60 toward the object. Here, the optical element 20 emits the irradiation beam 51 from the light generating device 60 that is incident on the optical element 20 toward at least one optical element of the imaging optical system 10 that is arranged on the object side with respect to the optical element 20. The illumination beam 51 emitted toward at least one optical element of the imaging optical system 10 that is arranged on the object side with respect to the optical element 20 is emitted toward the object. Therefore, it can be said that the optical element 20 of the imaging optical system 10 emits the illumination beam 51 from the light generating device 60 toward the object. The position at which the optical element 20 is arranged is not limited to the position described above. The optical element 20 may be arranged closest to the image plane 210 of the imaging optical system 10. Even in this case, the optical element 20 can be considered to be part of the imaging optical system 10.The imaging device 30 captures at least a portion of the image of an object formed on the image plane 210 by the imaging optical system 10. The position changing device 40 changes the incident position of the illumination beam 51 from the light generating device 60 onto the imaging optical system 10, thereby changing the irradiation position of the illumination beam 51 emitted from the imaging optical system 10.

[0071] 3 is a diagram illustrating an example of the configuration of the light transmitting and receiving optical element according to the first embodiment. An example of the configuration of the light transmitting and receiving optical element 41 will be described with reference to the same figure. The light transmitting and receiving optical element 41 includes at least a portion of an optical fiber 61, a Fresnel lens 42, and a collimating lens 46. An end of the optical fiber 61 is disposed near the Fresnel lens 42. For example, the light transmitting and receiving optical element 41 may include an end of the optical fiber 61 disposed near the Fresnel lens 42. It should be noted that a diffractive optical element may be used instead of the Fresnel lens.

[0072] Light for optical wireless communication (illumination beam 51) generated by the communication board 62 passes through the optical fiber 61 and enters the Fresnel lens 42. The illumination beam 51 exiting the Fresnel lens 42 enters the collimator lens 46. Here, the collimator lens 46 focuses the incident illumination beam 51 on the conjugate surface 220. After being focused at the conjugate surface 220, the illumination beam 51 exiting the collimator lens 46 diverges and enters the optical element 20. The optical element 20 emits the illumination beam 51 incident via the conjugate surface 220 toward the imaging optical system 10. Furthermore, the illumination beam 51 incident on the imaging optical system 10 from the other light irradiation device 1 in the optical wireless communication is focused at the conjugate surface 220 by the imaging optical system 10 and the optical element 20. The light (illumination beam 51) diverging via the conjugate surface 220 is collimated by the collimator lens 46 and enters the Fresnel lens 42. The light (illumination beam 51 ) emitted from the Fresnel lens 42 is converged and enters the optical fiber 61 .

[0073] The optical fiber 61 includes, for example, an optical fiber 61-1 for transmitting light (illumination beam 51) generated in the communication board 62 from the communication board 62 to the light transmitting and receiving optical element 41, and an optical fiber 61-2 for transmitting the illumination beam 51 incident on the imaging optical system 10 from the light irradiation device 1 of the other party in the optical wireless communication from the light transmitting and receiving optical element 41 to the communication board 62. In addition, the Fresnel lens 42 includes, for example, a Fresnel lens 42-1 for collimating divergent light (illumination beam 51) emitted from an end of the optical fiber 61-1 and emitting the divergent light toward the collimating lens 46, and a Fresnel lens 42-2 for converging the parallel light (illumination beam 51) from the collimating lens 46 so that the parallel light is incident on the end of the optical fiber 61-2.

[0074] With the above configuration, the light transmitting and receiving optical element 41 can receive, in a stationary state, light (illumination beam 51) incident thereon through the same optical path as the light (illumination beam 51) emitted from the imaging optical system 10, passing from the light transmitting and receiving optical element 41 through the conjugate plane 220 and the optical member 20 before being emitted from the imaging optical system 10. Therefore, as an example, in a state where the positional relationship with the other light irradiation device 1 with which it performs optical wireless communication does not change, the light irradiation device 1 can cause the irradiation beam 51 to be incident on the light transmitting and receiving optical element 41 of the other light irradiation device 1, while receiving the irradiation beam 51 emitted from the other light irradiation device 1 with the light transmitting and receiving optical element 41.

[0075] The position changing device 40 may integrally move the collimator lens 46, the Fresnel lens 42-1, the Fresnel lens 42-2, the end of the optical fiber 61-1, and the end of the optical fiber 61-2. In this case, the positional relationship between the collimator lens 46, the Fresnel lens 42-1, the Fresnel lens 42-2, the end of the optical fiber 61-1, and the end of the optical fiber 61-2 may be fixed by a structure (not shown).

[0076] At least one of the communication board 62, the optical fiber 61-1, the Fresnel lens 42-1, the collimator lens 46, the optical element 20, and the imaging optical system 10 may be referred to as a light emitting unit or a light emitting device that emits light (irradiation beam 51) through the imaging optical system 10. Also, at least one of the imaging optical system 10, the optical element 20, the collimator lens 46, the Fresnel lens 42-2, the optical fiber 61-2, and the communication board 62 may be referred to as a light receiving unit or a light receiving device that receives light (irradiation beam 51) incident through the imaging optical system 10 from the light irradiation device 1 of the other party in the optical wireless communication. The above-mentioned light receiving unit and light emitting unit can be collectively regarded as a light transmitting and receiving unit. The above-mentioned light receiving device and light emitting device can be collectively regarded as a light transmitting and receiving device.

[0077] The collimating lens 46 may be divided into a lens for converging the light (illumination beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220 and a lens for collimating the divergent light (illumination beam 51) from the conjugate plane 220 toward the Fresnel lens 42-2. In this case, at least one of at least a portion of the optical fiber 61-1 (for example, the end of the optical fiber 61-1 on the Fresnel lens 42-1 side), the Fresnel lens 42-1, and the lens for converging the light (illumination beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220 may be referred to as a light-transmitting optical element or a light-transmitting optical system. The light-transmitting optical element (light-transmitting optical system) is not limited to the above-described configuration. The light-transmitting optical element (light-transmitting optical system) may be composed of at least one other existing optical element as long as it can emit the light (illumination beam 51) from the optical fiber 61-1 toward the optical member 20A. Furthermore, at least one of the lens for collimating the light (illumination beam 51) diverging from the conjugate plane 220 toward the Fresnel lens 42-2, the Fresnel lens 42-2, and at least a portion of the optical fiber 61-2 (for example, the end of the optical fiber 61-2 on the Fresnel lens 42-2 side) may be referred to as a light-receiving optical element or a light-receiving optical system. Note that the light-receiving optical element (light-receiving optical system) is not limited to the above-described configuration. The light-receiving optical element (light-receiving optical system) may be composed of at least one other existing optical member as long as it can emit light (illumination beam 51) from the optical member 20A toward the optical fiber 61-2. At least one of the communication board 62, the optical fiber 61-1, the Fresnel lens 42-1, the lens for focusing the light (illumination beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220, the optical member 20, and the imaging optical system 10 may be referred to as a light emitting unit or a light emitting device that emits the light (illumination beam 51) via the imaging optical system 10. In other words, the light-transmitting optical element (light-transmitting optical system) may be referred to as a light emitting unit.Furthermore, at least one of the imaging optical system 10, the optical member 20, the lens for collimating the divergent light (irradiation beam 51) from the conjugate surface 220 toward the Fresnel lens 42-2, the Fresnel lens 42-2, the optical fiber 61-2, and the communication board 62 may be referred to as a light receiving unit or a light receiving device that receives the light (irradiation beam 51) incident via the imaging optical system 10 from the other light irradiator 1 in the optical wireless communication. In other words, the light receiving optical element (light receiving optical system) can be considered as the light receiving unit. Note that the above-mentioned light receiving unit (light receiving device) and light emitting unit (light emitting device) may be collectively considered as the light transmitting and receiving unit (light transmitting and receiving device).

[0078] According to the above configuration, the optical path of light (illumination beam 51) from the light-transmitting optical element through the conjugate surface 220 and the optical member 20 until it is emitted from the imaging optical system 10 is different from the optical path of light (illumination beam 51) from the imaging optical system 10 through the optical member 20 and the conjugate surface 220 until it is incident on the light-receiving optical element. Therefore, the light-transmitting and receiving optical element 41 can receive light (illumination beam 51) that is incident via an optical path different from the optical path of light (illumination beam 51) emitted from the imaging optical system 10 through the light-transmitting and receiving optical element 41 through the conjugate surface 220 and the optical member 20 until it is emitted from the imaging optical system 10. Therefore, the light irradiation device 1 can receive the irradiation beam 51 emitted from a position (for example, a position other than the predetermined position of the optical element closest to the object in the imaging optical system 10B) different from the irradiation position of the irradiation beam 51 on the other light irradiation device 1 with which it is communicating optically wirelessly (for example, a position other than the predetermined position of the optical element closest to the object in the imaging optical system 10B, i.e., a position other than the position where the irradiation beam 51 from the light irradiation device 1A is incident).

[0079] In this case, the position changing device 40 may separately move the light-transmitting optical element (the end of the optical fiber 61-1, the Fresnel lens 42-1, and a lens for converging the light (illumination beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220) and the light-receiving optical element (the lens for collimating the light (illumination beam 51) diverging from the conjugate plane 220 toward the Fresnel lens 42-2, the Fresnel lens 42-2, and the end of the optical fiber 61-2).

[0080] For example, the position changing device 40 may include a drive device that integrally moves the end of the optical fiber 61-1, the Fresnel lens 42-1, and a lens for focusing the light (illumination beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220, and a drive device that integrally moves the lens for collimating the light (illumination beam 51) diverging from the conjugate plane 220 toward the Fresnel lens 42-2, the Fresnel lens 42-2, and the end of the optical fiber 61-2. Note that the end of the optical fiber 61-1, the Fresnel lens 42-1, and the lens for focusing the light (illumination beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220 may be referred to as a light emitting unit. Furthermore, at least one of the lens for collimating the light (illumination beam 51) diverging from the conjugate plane 220 toward the Fresnel lens 42-2, the Fresnel lens 42-2, and the end of the optical fiber 61-2 may be referred to as a light receiving unit. In this case, the position changing device 40 can be considered to include a drive device that moves the light emitting portion and a drive device that moves the light receiving portion.

[0081] The positional relationship between the end of the optical fiber 61-1, the Fresnel lens 42-1, and the lens for concentrating the light (illumination beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220 may be fixed by a structure not shown. The positional relationship between the lens for collimating the light (illumination beam 51) diverged from the conjugate plane 220 toward the Fresnel lens 42-2, the Fresnel lens 42-2, and the end of the optical fiber 61-2 may be fixed by a structure not shown.

[0082] As described above, the position changing device 40 may change the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 by moving the light transmitting and receiving optical element 41 in the x-axis direction and the z-axis direction (e.g., directions perpendicular to the optical axis 111a of the imaging optical system 10) relative to the optical member 20. The control device 50 may change the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 based on the imaging result of the imaging device 30. Specifically, the control device 50 may identify the position of a characteristic part of an object on the image acquired by the imaging device 30 by the above-mentioned image processing. The control device 50 may control the position changing device 40 (or move the light transmitting and receiving optical element 41) based on the identified position of the characteristic part on the image so that the irradiation beam 51 emitted from the imaging optical system 10 is incident on the other light irradiation device 1 in the optical wireless communication. In order to more accurately irradiate the irradiation beam 51 to the target position (e.g., a specific position on the optical element closest to the object in the imaging optical system 10B) of the other light irradiation device 1 in the optical wireless communication, and to more accurately receive the irradiation beam 51 emitted from the other light irradiation device 1 in the optical wireless communication at the target position (e.g., the light transmitting and receiving optical system 41 positioned at a specific position in the direction intersecting with the optical axis 111a), at least one of the calibration of the imaging device 30 and the calibration of the light transmitting and receiving optical element 41 may be performed.

[0083] An example of calibration will now be described. First, as calibration of the imaging device 30, distortion correction of the imaging result by the imaging device 30 may be performed. Next, as calibration of the light transmitting and receiving optical element 41, correspondence may be established between the position of the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111a (i.e., the position on the conjugate plane 220 of the irradiation beam 51) and the position on the image acquired by the imaging device 30. As an example of distortion correction of the imaging result by the imaging device 30, distortion correction of the image acquired by the imaging device 30 may be performed by imaging a board on which marks of a known shape, such as a checkerboard pattern, are formed (hereinafter referred to as a calibration board) with the imaging device 30. The light irradiation device 1 may perform distortion correction of the image acquired by the imaging device 30 using a well-known method based on the imaging result of the checkerboard by the imaging device 30. For example, the light irradiation device 1 may perform distortion correction of the imaging device 30 by adjusting known image processing conditions of the imaging device 30 based on a comparison result between the imaging result of the calibration board by the imaging device 30 and the shape of a known mark formed on the calibration board. Note that the calibration of the imaging device 30 may be referred to as calibration of the imaging optical system 10 or calibration of the optical element 20, since the calibration is performed by the imaging device 30 capturing an image formed by light passing through the imaging optical system 10 and the optical element 20. Next, the light irradiation device 1 may associate the position of the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111a with the position on the image acquired by the imaging device 30. The association between the position of the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111a with the position on the image acquired by the imaging device 30 may be performed using, for example, a screen or a retroreflective surface (hereinafter simply referred to as a reflective surface).

[0084] The light irradiation device 1 may irradiate light from the light transmitting and receiving optical element 41 toward the reflective surface via the imaging optical system 10, and the imaging device 30 may receive light that is irradiated from the imaging optical system 10 toward the reflective surface and reflected by the reflective surface, thereby associating the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a with the position on the image acquired by the imaging device 30. As described above, when the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a changes, the irradiation position (irradiation direction) of the light emitted from the imaging optical system 10 changes. Therefore, when the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a changes, the reflection position on the reflective surface also changes, and therefore the incident position of the reflected light on the imaging device 30 (the imaging surface of the imaging element 31) also changes (i.e., the position of the reflected light on the image acquired by the imaging device 30 also changes). It can also be said that the light irradiation device 1 calibrates the light transmitting and receiving optical element 41 based on the position of the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111a and the position of reflected light on the image acquired by the imaging device 30. Note that the calibration of the light transmitting and receiving optical element 41 may also be referred to as calibration of the light transmitting and receiving optical element 41 and the imaging device 30, calibration of the position changing device 40, or calibration of the position changing device 40 and the imaging device 30. Note that the method of associating the position of the light transmitting and receiving optical element 41 in the direction intersecting the optical axis 111a with the position on the image acquired by the imaging device 30 is not limited to the above method using the reflecting surface.

[0085] The light irradiation device 1 may perform calibration of the imaging device 30 and calibration of the light transmitting and receiving optical element 41 using a calibration board (hereinafter referred to as a dual-purpose calibration board) on which both a mark with a known shape for the above-mentioned distortion correction and a reflective surface for calibrating the above-mentioned light transmitting and receiving optical element 41 are formed. For example, the light irradiation device 1 may be arranged so that the known mark and the reflective surface are included in the field of view of the imaging optical system 10, and may receive light reflected from the reflective surface due to irradiation of light from the imaging optical system 10 and may also image the known mark. By using the dual-purpose calibration board, calibration of the imaging device 30 and the light transmitting and receiving optical element 41 can be performed simultaneously.

[0086] By performing the above calibration, it is possible to further improve the accuracy of the irradiation position of the irradiation beam 51 at the target position of the other light irradiation device 1 in the optical wireless communication (for example, a specific position on the optical member closest to the object side of the imaging optical system 10B). Also, it is possible to further improve the accuracy of the light receiving position of the irradiation beam 51 emitted from the other light irradiation device 1 in the optical wireless communication (for example, the positioning accuracy of the light transmitting and receiving optical system 41 in the direction intersecting with the optical axis 111a). Note that the positional relationship between the imaging device 30 and the light transmitting and receiving optical element 41 may be ensured by improving the mechanical accuracy of a holding mechanism (not shown) that holds the wide-angle sensor 31 and the light transmitting and receiving optical element 41.

[0087] Next, an example of optical wireless communication performed by the light irradiation device 1 will be described with reference to FIGS. 4 to 6 . In this example, a light irradiation system 100 is configured to include a plurality of light irradiation devices 1 (e.g., light irradiation device 1A and light irradiation device 1B), and one-to-one optical wireless communication is performed between the light irradiation device 1A and the light irradiation device 1B. However, this embodiment is not limited to one example of one-to-one wireless communication, and one-to-N or N-to-M wireless communication (N and M are natural numbers greater than or equal to 1) may also be performed. Optical wireless communication is not limited to one example of bidirectional communication, and includes unidirectional communication in which only transmission or only reception is performed.

[0088] 4 is a diagram showing a first example of optical wireless communication according to the first embodiment. In the example shown in the figure, a light irradiation device 1A and a light irradiation device 1B are disposed at positions substantially opposite each other in the x-y plane. The light irradiation device 1A emits an irradiation beam 51 in the positive direction of the x-axis. The light irradiation device 1A receives the irradiation beam 51 emitted from the light irradiation device 1B in the negative direction of the x-axis. The light irradiation device 1B emits an irradiation beam 51 in the negative direction of the x-axis. The light irradiation device 1B receives the irradiation beam 51 emitted from the light irradiation device 1A in the positive direction of the x-axis.

[0089] 5 is a diagram showing a second example of optical wireless communication according to the first embodiment. In the example shown in the figure, the light irradiation device 1A and the light irradiation device 1B are installed at positions tilted by approximately 90 degrees in the x-y plane. The light irradiation device 1A emits an irradiation beam 51 in the positive direction of the x-axis. The light irradiation device 1A receives the irradiation beam 51 emitted from the light irradiation device 1B in the negative direction of the x-axis. The light irradiation device 1B emits the irradiation beam 51 in the negative direction of the x-axis. The light irradiation device 1B receives the irradiation beam 51 emitted from the light irradiation device 1A in the positive direction of the x-axis.

[0090] Here, a process will be described when the positional relationship between the light irradiation device 1A and the light irradiation device 1B, which are optically wirelessly communicated in FIG. 4 (hereinafter referred to as the positional relationship in FIG. 4 ), changes to the positional relationship between the light irradiation device 1A and the light irradiation device 1B in FIG. 5 (hereinafter referred to as the positional relationship in FIG. 5 ). In the following description, the process of the light irradiation device 1A will be described as an example. In this case, the light irradiation device 1A may be installed on the above-mentioned movable body. The positional relationship between the light irradiation device 1A and the light irradiation device 1B may change as the movable body moves. The position of not only the light irradiation device 1A but also the light irradiation device 1B may change. For example, the light irradiation device 1B may be installed on the above-mentioned movable body. The positional relationship between the light irradiation device 1A and the light irradiation device 1B may change as the movable body moves.

[0091] When the positional relationship in FIG. 4 changes to the positional relationship in FIG. 5 , the light irradiation device 1A rotates approximately −90° in the x-y plane. That is, the position of the light irradiation device 1B changes as seen from the light irradiation device 1A. When the position of the light irradiation device 1B changes as seen from the light irradiation device 1A, the position of a characteristic feature of the light irradiation device 1B (e.g., a marker placed on the light irradiation device 1B) on the image acquired by the imaging device 30A also changes. Here, the control device 50A may perform imaging using the imaging device 30A at a predetermined frame rate, and each time an image is acquired, identify the position of the characteristic feature of the light irradiation device 1B on the acquired image using the image processing described above, and control the position change device 40A so that the irradiation beam 51 from the light irradiation device 1A is incident on the communication board 62B via the imaging optical system 10B. Furthermore, the control device 50A may detect a displacement between the position of a characteristic feature of the light irradiation device 1B on an image acquired by the imaging device 30A when the positional relationship shown in FIG. 4 is in the optical wireless communication state and the position of the characteristic feature of the light irradiation device 1B on an image acquired by the imaging device 30A after the positional relationship between the light irradiation device 1A and the light irradiation device 1B has changed, and control the position changing device 40A based on the detected displacement. In this case, the control device 50A may control the position changing device 40A to apply a displacement to the light transmitting and receiving optical element 41A in a direction intersecting the optical axis 111a corresponding to the detected displacement on the image. In other words, the control device 50A may control the position changing device 40A based on the displacement of the characteristic feature of the light irradiation device 1B on an image detected from multiple images acquired at a predetermined frame rate.

[0092] The above-described processing and control by the control device 50A allows the light irradiation device 1A to continue irradiating the irradiation beam 51 to the light irradiation device 1B (communication board 60B) even if the position of the light irradiation device 1A changes, changing the positional relationship between the light irradiation device 1A and the light irradiation device 1B. In other words, even if the positional relationship between the light irradiation device 1A and the light irradiation device 1B changes, the light irradiation device 1A and the light irradiation device 1B can continue optical wireless communication. Note that the above-described processing and control associated with changes in the positional relationship between the light irradiation device 1A and the light irradiation device 1B may be performed by the control device 50B instead of the control device 50A, or may be performed by the control device 50A and the control device 50B separately.

[0093] 6 is a diagram showing a third example of optical wireless communication according to the first embodiment. In the example shown in the figure, the light irradiation device 1A and the light irradiation device 1B are installed on substantially the same y-z plane and are installed at positions facing substantially the same direction in the x-y plane. The light irradiation device 1A emits an irradiation beam 51 in the positive direction of the x-axis. The light irradiation device 1A also receives the irradiation beam 51 emitted from the light irradiation device 1B in the negative direction of the x-axis. The light irradiation device 1B also emits an irradiation beam 51 in the negative direction of the x-axis. The light irradiation device 1B also receives the irradiation beam 51 emitted from the light irradiation device 1A in the positive direction of the x-axis.

[0094] The processing performed when the positional relationship between the light irradiation device 1A and the light irradiation device 1B in FIG. 6 (hereinafter referred to as the positional relationship in FIG. 6) changes from the positional relationship in FIG. 5 where the light irradiation device 1A and the light irradiation device 1B are wirelessly communicated is described below. In the following description, the processing performed by the light irradiation device 1A is described as an example. When the positional relationship in FIG. 5 changes to the positional relationship in FIG. 6, the light irradiation device 1B rotates approximately 90° in the x-y plane. That is, the position of the light irradiation device 1B changes as viewed from the light irradiation device 1A. Similarly to the above, the control device 50A may perform imaging using the imaging device 30A at a predetermined frame rate, and each time an image is acquired, the control device 50A may identify the position of a characteristic feature of the light irradiation device 1B on the acquired image using the image processing described above, and control the position change device 40A so that the irradiation beam 51 from the light irradiation device 1A is incident on the communication board 62B. 5 in the optical wireless communication state, and the characteristic location of the light irradiation device 1B on the image acquired by the imaging device 30A after the positional relationship between the light irradiation device 1A and the light irradiation device 1B has changed, and the control device 50A may control the position changing device 40A based on the detected displacement. In this case, the control device 50A may control the position changing device 40A to apply a displacement to the light transmitting and receiving optical element 41A in a direction intersecting the optical axis 111a corresponding to the detected displacement on the image.

[0095] By the above processing of the control device 50A, even if the positional relationship between the light irradiation devices 1A and 1B changes due to a change in the position of the light irradiation device 1B, the light irradiation devices 1A and 1B can continue optical wireless communication. Note that the above processing and control associated with a change in the positional relationship between the light irradiation devices 1A and 1B may be executed by the control device 50B instead of the control device 50A, or may be executed by the control device 50A and the control device 50B separately.

[0096] In the explanation given with reference to Figures 4 to 6, we have described the case where the positional relationship between light irradiation device 1A and light irradiation device 1B changes in the xy plane, but even if the relationship changes in the yz plane or the xz plane, the optical wireless communication state between light irradiation device 1A and light irradiation device 1B can be maintained by using the same processing and control as described above.

[0097] Furthermore, in the process of changing from the positional relationship in Fig. 4 to the positional relationship in Fig. 5 and to the positional relationship in Fig. 6, the light irradiation device 1A may change the frame rate of the image captured by the imaging device 30A. For example, the light irradiation device 1A may set a frame rate higher when there is displacement of the light irradiation device 1B (e.g., the imaging optical system 10B or a marker arranged on the light irradiation device 1B) on the image captured by the imaging device 30A than when there is no such displacement.

[0098] Note that the target (object) with which the light irradiation device 1A communicates optically wirelessly is not limited to the light irradiation device 1B. For example, the target with which the light irradiation device 1A communicates optically wirelessly may be a light receiving device (described later) capable of optically wirelessly communicating with the light irradiation device 1A by receiving an irradiation beam 51 (light for optically wireless communication) from the light irradiation device 1A. For example, the target (object) with which the light irradiation device 1A communicates optically wirelessly may be a light transmitting device (described later) capable of optically wirelessly communicating with the light irradiation device 1A by irradiating an irradiation beam 51 toward the light irradiation device 1A. For example, the target (object) with which the light irradiation device 1A communicates optically wirelessly may be a light transmitting / receiving device (described later) different from the light irradiation device 1B that receives the irradiation beam 51 (light for optically wireless communication) from the light irradiation device 1A and irradiates the irradiation beam 51 toward the light irradiation device 1A.

[0099] Fig. 7 is a schematic configuration diagram showing a modified example of the light irradiation system according to the first embodiment. An optical wireless communication system 100A, which is a modified example of the light irradiation system 100, will be described with reference to the same figure. As shown in Fig. 7, the optical wireless communication system 100A includes a light irradiation device 1, a plurality of light receiving devices 81, a plurality of light transmitting devices 82, and a plurality of light transmitting and receiving devices 83. The present embodiment is not limited to this example. The optical wireless communication system 100A may include one or more light irradiation devices 1, and zero or one or more light receiving devices 81, light transmitting devices 82, and light transmitting and receiving devices 83.

[0100] The light-receiving device 81 may be a counterpart device that communicates optically wirelessly with the light irradiating device 1A. The light-receiving device 81 may include a light-receiving unit 811. The light irradiating device 1A is capable of optically wirelessly communicating with the light-receiving device 81 by causing the irradiation beam 51, which is light emitted from the light irradiating device 1A and used for optical wireless communication, to be incident on the light-receiving unit 811. The light-receiving device 81 does not need to have a configuration for irradiating the irradiation beam 51. The light-receiving unit 811 may include a communication board 62. The communication board 62 included in the light-receiving unit 811 does not need to have a configuration for generating the irradiation beam 51. In addition to the communication board 62, the light-receiving unit 811 may include at least one of the imaging optical system 10, the optical member 20, a lens for collimating light (irradiation beam 51) diverged from the conjugate surface 220 toward the Fresnel lens 42-2, the Fresnel lens 42-2, and the optical fiber 61-2. The light receiving unit 811 may have a configuration omitting the configuration for emitting the irradiation beam 51 from the light irradiation device 1. The light receiving device 81 is not limited to the above configuration, and may have an existing configuration (for example, a light receiving element that converts the received irradiation beam 51 into an electrical signal) that is capable of optical wireless communication with the light irradiation device 1A by receiving the irradiation beam 51 from the light irradiation device 1A. The light receiving device 81 may be provided with the above-mentioned characteristic parts. The positional relationship between the characteristic parts of the light receiving device 81 and the light receiving unit 811 of the light receiving device 81 may be known.

[0101] The light receiving section 811 of the light receiving device 81 is an example of an object onto which the light irradiation device 1A irradiates the irradiation beam 51. That is, the irradiation beam 51 is irradiated onto the light receiving section 811. In this example, the irradiation beam 51 may be referred to as a light beam for optical wireless communication with the light receiving device 81. The irradiation beam 51 (light beam) may also be referred to as highly directional light.

[0102] The light transmitting device 82 may be a counterpart device that communicates optically wirelessly with the light irradiation device 1A. The light transmitting device 82 may include a light transmitting unit 821. The light transmitting unit 821 may emit an irradiation beam 51 as light for optically wirelessly communicating with the light irradiation device 1A. The light irradiation device 1A is capable of optically wirelessly communicating with the light transmitting device 82 by receiving the irradiation beam 51 from the light transmitting unit 821 with a light transmitting / receiving optical element 41A (communication board 62A). The light transmitting device 82 does not need to be equipped with a configuration for receiving the irradiation beam 51. The light transmitting unit 821 may include a communication board 62. The communication board 62 included in the light transmitting unit 821 does not need to be equipped with a configuration for receiving the irradiation beam 51. In addition to the communication board 62, the light-sending unit 821 may include at least one of the optical fiber 61-1, the Fresnel lens 42-1, a lens for focusing light (illumination beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220, the optical member 20, and the imaging optical system 10. The light-sending unit 821 may be configured without a component for receiving the illumination beam 51 emitted from the light irradiation device 1. The light-sending device 82 is not limited to the above-described configuration and may include an existing component (e.g., a light-emitting element that converts an electrical signal into the illumination beam 51) that is capable of optically communicating wirelessly with the light irradiation device 1A by irradiating the illumination beam 51 to the light irradiation device 1A. The light-sending device 82 may be provided with the above-described characteristic features. The positional relationship between the characteristic features of the light-sending device 82 and the light-sending unit 821 may be known. The light-sending device 82 may also be referred to as a light-emitting device or a light-emitting unit. The light sending unit 821 may also be referred to as a light emitting device or a light emitting unit. In the following description, the irradiation beam 51, which is light incident on the light irradiation device 1 and is emitted from the light sending device 82 (light sending unit 821), will be referred to as an incident beam 52. The incident beam 52 may also be referred to as an irradiation beam 51 emitted from the light sending device 82 for optical wireless communication with the light irradiation device 1A. The incident beam 52 may also be referred to as a light beam for optical wireless communication between the light irradiation device 1A and the light sending device 82. The incident beam 52 (light beam) may also be referred to as highly directional light.

[0103] The light transmitting / receiving device 83 may include a light receiving unit 831 and a light transmitting unit 832. The light receiving unit 831 may receive the irradiation beam 51 from the light irradiation device 1A. The light transmitting unit 832 may irradiate the irradiation beam 51 to the light irradiation device 1A. The light receiving unit 831 may have the same configuration as the light receiving unit 811 described above. The light transmitting unit 832 may have the same configuration as the light transmitting unit 821 described above. As shown in FIG. 7 , the light receiving unit 831 and the light transmitting unit 832 may be arranged adjacent to each other on the light transmitting / receiving device 83, or may be arranged spaced apart. The light transmitting / receiving device 83 may have the same configuration as the light irradiation device 1 described above. In other words, at least one light transmitting / receiving device 83 may be at least one light irradiation device 1 that is a counterpart of the light irradiation device 1A that performs optical wireless communication with the light irradiation device 1A. One of the at least one light transmitting / receiving device 83 may be the light irradiation device 1B described above. The above-described characteristic parts may be provided in the light transmitting and receiving device 83. The positional relationship between the characteristic parts of the light transmitting and receiving device 83 and at least one of the light receiving unit 831 and the light transmitting unit 832 of the light transmitting and receiving device 83 may be known.

[0104] Incidentally, the irradiation beam 51, which is light incident on the light irradiation device 1 and is emitted from the light transmitting unit 832 of the light transmitting and receiving device 83, will be referred to as the incident beam 52. Incidentally, the incident beam 52 may also be referred to as the irradiation beam 51 emitted from the light transmitting unit 832 of the light transmitting and receiving device 83 for optical wireless communication with the light irradiation device 1. Incidentally, the irradiation beam 51 and the incident beam 52 may also be referred to as light beams for optical wireless communication between the light irradiation device 1A and the light transmitting and receiving device 83. Incidentally, the irradiation beam 51 (light beam) and the incident beam 52 (light beam) may also be referred to as highly directional light.

[0105] The light-transmitting device 82 may be an example of a light-transmitting and receiving device 83 including a light-receiving unit 831. In this case, the incident beam 52 is emitted from the light-transmitting and receiving device 83, and the irradiation beam 51 is irradiated onto the light-receiving unit 831. The incident beam 52 and the irradiation beam 51 may each be referred to as an optical beam for optical wireless communication between the light irradiation device 1A and the light-transmitting and receiving device 83. The light-receiving device 81 may be an example of a light-transmitting and receiving device 83 including a light-transmitting unit 821. Hereinafter, various combinations of devices in the light irradiation system 100A will be described.

[0106] First, an example will be described in which the optical wireless communication system 100A includes a light emitting device 1A and a light receiving device 81. In the optical wireless communication system 100A, the light emitting device 1A and the light receiving device 81 may communicate optically wirelessly with each other by receiving an irradiation beam 51 from the light emitting device 1A with a light receiving unit 811 of the light receiving device 81. That is, in this example, the optical wireless communication system 100A may transmit information from the light emitting device 1A to the light receiving device 81.

[0107] When optical wireless communication is performed between the light emitting device 1A and the light receiving device 81, the light emitting device 1A may be configured without a component for receiving the irradiation beam 51. For example, the light emitting device 1A may not include a lens for collimating the divergent light (irradiation beam 51) from the conjugate plane 220 toward the Fresnel lens 42-2, the Fresnel lens 42-2, and the optical fiber 61-2. For example, the light emitting device 1A may include the above-mentioned light transmitting optical element (light emitting unit) instead of the light transmitting and receiving optical element 41.

[0108] The control device 50A of the light irradiation device 1A may control the position changing device 40A so that the irradiation beam 51 from the light irradiation device 1A is incident on the light receiving unit 811 based on the position of a characteristic part of the light receiving device 81 as an object on the image acquired by the imaging device 30A (for example, a marker placed on the light receiving device 81), which is identified by the above-mentioned image processing, and the positional relationship between the characteristic part of the light receiving device 81 and the light receiving unit 811 of the light receiving device 81.

[0109] Furthermore, when the positional relationship between the light irradiation device 1A and the light receiving device 81 changes, the control device 50A may perform imaging using the imaging device 30A at a predetermined frame rate, and each time an image is acquired, identify the position of a characteristic part of the light receiving device 81 on the acquired image using the image processing described above, and control the position changing device 40A so that the irradiation beam 51 from the light irradiation device 1A is incident on the light receiving unit 811.

[0110] The control device 50A may detect the displacement of a characteristic part of the light-receiving device 81 on the image by identifying the position of the characteristic part of the light-receiving device 81 using the image processing described above for each image acquired at a predetermined frame rate. The control device 50A may control the position changing device 40A so that the irradiation beam 51 from the light irradiation device 1A is incident on the light-receiving unit 811 based on the displacement of the characteristic part on the image. By the processing and control of the control device 50A described above, even if the positional relationship between the light irradiation device 1A and the light-receiving device 81 changes, it is possible to continue optical wireless communication from the light irradiation device 1A to the light-receiving device 81. At least one of the light irradiation device 1A and the light-receiving device 81 may be installed on the movable body described above, and the positional relationship between the light irradiation device 1A and the light-receiving device 81 may be changed by moving the movable body.

[0111] Next, an example of an optical wireless communication system 100A including a light emitting device 1A and a light transmitting device 82 will be described. In the optical wireless communication system 100A, an incident beam 52 from the light transmitting device 82 may be received by an imaging optical system 10A (communication board 62A) of the light emitting device 1A, thereby enabling optical wireless communication between the light transmitting device 82 and the light emitting device 1A. That is, in this example, the optical wireless communication system 100A may transmit information from the light transmitting device 82 to the light emitting device 1A. Note that, when optical wireless communication is performed between the light emitting device 1A and the light transmitting device 82, the light emitting device 1A may be configured without a component for emitting the irradiation beam 51. For example, the light emitting device 1A may not include the optical fiber 61-1, the Fresnel lens 42-1, and a lens for focusing the light (irradiation beam 51) from the Fresnel lens 42-1 toward the conjugate plane 220. For example, the light irradiation device 1A may include the above-mentioned light receiving optical element (light receiving section) instead of the light transmitting and receiving optical element 41.

[0112] The control device 50A may control the position change device 40A so that the incident beam 52 from the light-transmitting unit 821 is incident on the imaging optical system 10A (communication board 62A) based on the position of a characteristic part of the light-transmitting device 82 as an object on the image acquired by the imaging device 30A (for example, a marker placed on the light-transmitting device 82), which is identified by the above-mentioned image processing, and the positional relationship between the characteristic part of the light-transmitting device 82 and the light-transmitting unit 821 of the light-transmitting device 82.

[0113] Furthermore, when the positional relationship between the light irradiation device 1A and the light transmitting device 82 changes, the control device 50A may perform imaging using the imaging device 30A at a predetermined frame rate, and each time an image is acquired, identify the position of a characteristic part of the light transmitting device 82 on the acquired image using the image processing described above, and control the position changing device 40A so that the incident beam 52 from the light transmitting device 82 is incident on the light transmitting and receiving optical element 41A.

[0114] The control device 50A may detect the displacement of a characteristic feature of the light-transmitting device 82 on the image by identifying the position of the characteristic feature of the light-transmitting device 82 using the image processing described above for each image acquired at a predetermined frame rate. The control device 50A may then control the position change device 40A so that the incident beam 52 from the light-transmitting device 82 is incident on the imaging optical system 10A (communication board 62A) based on the displacement of the characteristic feature on the image. The processing and control of the control device 50A described above allows for continued optical wireless communication from the light-transmitting device 82 to the light-transmitting device 1A even if the positional relationship between the light irradiation device 1A and the light-transmitting device 82 changes. At least one of the light irradiation device 1A and the light-transmitting device 82 is installed on the movable body described above, and the positional relationship between the light irradiation device 1A and the light-transmitting device 82 changes as the movable body moves.

[0115] Next, an example of an optical wireless communication system 100A including a light emitting device 1A and a light transmitting and receiving device 83 will be described. In the optical wireless communication system 100A, the light emitting device 1A may irradiate an irradiation beam 51 onto a light receiving unit 831 of the light transmitting and receiving device 83, and an incident beam 52 from a light transmitting unit 832 of the light transmitting and receiving device 83 may be received by an imaging optical system 10A (communication board 62A) of the light emitting device 1A, thereby enabling optical wireless communication between the light emitting device 1A and the light transmitting and receiving device 83. That is, in this example, the optical wireless communication system 100A may transmit and receive information between the light emitting device 1A and the light transmitting and receiving device 83.

[0116] For example, when the light receiving unit 831 and the light transmitting unit 832 are arranged adjacent to or close to each other on the light transmitting and receiving device 83, the control device 50A of the light irradiation device 1A may control the position changing device 40A so that the irradiation beam 51 is incident on the light receiving unit 831, based on the position of a characteristic part of the light transmitting and receiving device 83 as an object on the image acquired by the imaging device 30A (for example, a marker arranged on the light transmitting and receiving device 83), which is identified by the image processing described above, and the positional relationship between the characteristic part of the light transmitting and receiving device 83 and the light receiving unit 831 of the light transmitting and receiving device 83. Here, the irradiation beam 51 from the light transmitting unit 832 becomes a spread light because it is diffused to a certain extent depending on the distance from the light transmitting unit 832. Therefore, even if the control device 50A moves the light-transmitting and receiving optical element 41A so that the irradiation beam 51 is incident on the light-receiving unit 831 based on the position of the characteristic location on the image acquired by the imaging device 30A, the incident beam 52 from the light-transmitting unit 832 enters the imaging optical system 10A, passes through the optical member 20A, and is incident on the moved light-transmitting and receiving optical element 41A (i.e., is incident on the communication board 62A). Note that the control device 50A may control the position changing device 40A so that the incident beam 52 from the light-transmitting unit 832 is incident on the light-transmitting and receiving optical element 41A based on the position of the characteristic location of the light-transmitting and receiving device 83 as an object on the image acquired by the imaging device 30A, which is specified by the image processing described above, and the positional relationship between the characteristic location of the light-transmitting and receiving device 83 and the light-transmitting unit 832 of the light-transmitting and receiving device 83.

[0117] Furthermore, when the positional relationship between the light irradiation device 1A and the light transmitting and receiving device 83 changes, similar to the processing and control described above, the control device 50A performs imaging using the imaging device 30A at a predetermined frame rate, and each time an image is acquired, the position of a characteristic part of the light transmitting and receiving device 83 on the acquired image is identified using the image processing described above, and the position changing device 40A may be controlled so that the irradiation beam 51 from the light irradiation device 1A is incident on the light receiving unit 831 (or so that the incident beam 52 from the light transmitting unit 832 is incident on the light transmitting and receiving optical element 41A).

[0118] The control device 50A may detect the displacement of a characteristic part of the light transmitting and receiving device 83 on the image by identifying the position of the characteristic part of the light transmitting and receiving device 83 using the image processing described above for each image acquired at a predetermined frame rate. Then, the control device 50A may control the position changing device 40A so that the irradiation beam 51 from the light emitting device 1A is incident on the light receiving unit 831 (or so that the incident beam 52 from the light transmitting unit 832 is incident on the light transmitting and receiving optical element 41A) based on the displacement of the characteristic part on the image. The above processing and control by the control device 50A allows the light emitting device 1A and the light transmitting and receiving device 83 to continue bidirectional optical wireless communication even if the positional relationship between the light emitting device 1A and the light transmitting and receiving device 83 changes.

[0119] As described above, the light-transmitting and receiving optical system element 41A may be divided into a light-transmitting optical element and a light-receiving optical element. As described above, the position changing device 40A may include a drive device that moves the light-transmitting optical element and a drive device that moves the light-receiving optical element. In this case, the control device 50A may move the light-transmitting optical element so that the irradiation beam 51 emitted from the imaging optical system 10A via the optical member 20A is incident on the light-receiving unit 831 (i.e., may control the position changing device 40A) based on the position of the characteristic location of the light-transmitting and receiving device 83 on the image acquired by the imaging device 30A, which is identified by the image processing described above, and the positional relationship between the characteristic location of the light-transmitting and receiving device 83 and the light-receiving unit 831. Furthermore, the control device 50A may move the light-receiving optical element so that the incident beam 52 from the light-transmitting unit 832 is incident on the light-receiving optical element via the imaging optical system 10A and the optical member 20A (i.e., may control the position changing device 40A) based on the position of the characteristic part of the light-transmitting and receiving device 83 on the image acquired by the imaging device 30A, which is identified by the above-mentioned image processing, and the positional relationship between the characteristic part of the light-transmitting and receiving device 83 and the light-transmitting unit 832. By the above-mentioned processing and control of the control device 50A, even if the light-receiving unit 831 and the light-transmitting and receiving device 83 are not arranged adjacent to or close to each other, the light irradiation device 1A and the light-transmitting and receiving device 83 can perform bidirectional optical wireless communication.

[0120] In addition, when the positional relationship between the light irradiation device 1A and the light transmitting and receiving device 83 changes, the control device 50A may perform image capture using the imaging device 30A at a predetermined frame rate, and for each acquired image, identify the position of a characteristic feature of the light transmitting and receiving device 83 using the image processing described above to detect the displacement of the characteristic feature on the image. Then, based on the displacement of the characteristic feature on the image, the control device 50A may move the light transmitting optical element so that the irradiation beam emitted from the imaging optical system 10A is incident on the light receiving unit 832, or may move the light receiving optical system so that the incident beam 52 from the light transmitting unit 832 is incident on the imaging optical system 10A (communication board 62A). Through the above processing and control by the control device 50A, even if the positional relationship between the light irradiation device 1A and the light transmitting and receiving device 83 changes, the light irradiation device 1A and the light transmitting and receiving device 83 can continue bidirectional optical wireless communication. At least one of the light irradiation device 1A and the light transmitting / receiving device 83 may be installed on the movable body, and the positional relationship between the light irradiation device 1A and the light transmitting / receiving device 83 may be changed by moving the movable body.

[0121] Next, an example of an optical wireless communication system 100A including a light emitting device 1A and multiple light receiving devices 81 will be described. As an example, a case will be described in which the light emitting system 100A includes a light emitting device 1A, a first light receiving device 81-1 as an object (first object), and a second light receiving device 81-2 as an object (second object). When the optical wireless communication system 100A includes a light emitting device 1A and multiple light receiving devices 81, the light emitting device 1A may include multiple light generating devices 60A according to the number of light receiving devices 81 as objects to be irradiated. In other words, the light emitting device 1A may include multiple communication boards 62A, multiple optical fibers 61A, and multiple light transmitting and receiving optical elements 41. In this case, the light emitting device 1A can also be considered to have multiple light emitting units.

[0122] For example, if the optical wireless communication system 100A includes two light receiving devices 81 (a first light receiving device 81-1 and a second light receiving device 81-2), the light irradiating device 1A may include two light generating devices 60A (referred to as a first light generating device 60A-1 and a second light generating device 60A-2). That is, the light irradiating device 1A may include two communication boards 62A (referred to as a first communication board 62A-1 and a second communication board 62A-2), two optical fibers 61 (referred to as a first optical fiber 61-1 and a second optical fiber 61-2), and two light transmitting and receiving optical elements 41A (referred to as a first light transmitting and receiving optical element 41A-1 and a second light transmitting and receiving optical element 41A-2).

[0123] The light irradiation device 1A may emit light (referred to as a first irradiation beam 51-1) generated by the first communication board 62A-1 for optically wirelessly communicating with the first light receiving device 81-1 via the first optical fiber 61-1, the first light transmitting and receiving optical element 41A-1, the optical member 20A, and the imaging optical system 10A. The light irradiation device 1A may also emit light (referred to as a second irradiation beam 51-2) generated by the second communication board 62A-2 for optically wirelessly communicating with the second light receiving device 81-2 via the second optical fiber 61-2, the second light transmitting and receiving optical element 41A-2, the optical member 20A, and the imaging optical system 10A.

[0124] The first irradiation beam 51-1 and the second irradiation beam 51-2 may have different optical conditions. For example, the optical conditions include at least one of wavelength, frequency, phase, and polarization state. The light irradiation device 1A may generate the first irradiation beam 51-1 and the second irradiation beam 51-2 using a common communication board 62A. The light irradiation device 1A may be configured without a component for receiving the irradiation beam 51 (incident beam 52). For example, at least one of the light transmitting and receiving optical elements 41-1 and 41-2 may be the above-mentioned light transmitting optical element (i.e., the light emitting unit). The position changing device 40A moves the first light transmitting and receiving optical element 41-1 and the second light transmitting and receiving optical element 41-2 individually in a direction intersecting the above-mentioned optical axis 111a. For example, the position changing device 40A may include a drive device that moves the first light transmitting and receiving optical element 41-1 in a direction intersecting the optical axis 111a, and a drive device that moves the second light transmitting and receiving optical element 41-2 in a direction intersecting the optical axis 111a. Note that the position changing device 40A may move the first light transmitting and receiving optical element 41-1 and the second light transmitting and receiving optical element 41-2 integrally in the direction intersecting the optical axis 111a.

[0125] The first light receiving device 81-1 may include a first light receiving unit 811-1, and the second light receiving device 81-2 may include a second light receiving unit 811-2. The first light receiving device 81-1 and the second light receiving device 81-2 may each be provided with the above-described characteristic location. The characteristic location provided on the first light receiving device 81-1 and the characteristic location provided on the second light receiving device 81-2 may be distinguishable. For example, the characteristic location provided on the first light receiving device 81-1 and the characteristic location provided on the second light receiving device 81-2 may be markers with different shapes. In this case, the control device 50A may distinguishably identify the positions of the characteristic locations provided on the first light receiving device 81-1 and the second light receiving device 81-2 based on the recognition results of the respective characteristic locations provided on the two light receiving devices 81 on the image acquired by the imaging device 30A. The positional relationship between the characteristic location of the first light receiving device 81-1 and the first light receiving unit 811-1 of the first light receiving device 81-1 may be known. The positional relationship between the characteristic location of the second light receiving device 81-2 and the second light receiving unit 811-2 of the second light receiving device 81-2 may be known.

[0126] The optical wireless communication system 100A may perform optical wireless communication from the light emitting device 1A to the first light receiving device 81-1 by receiving, at the light receiving unit 811-1 of the first light receiving device 81-1, a first irradiation beam 51-1 emitted from the first light transmitting and receiving optical element 41-1 provided in the light emitting device 1A via the optical member 20A and the imaging optical system 10A. The optical wireless communication system 100A may also perform optical wireless communication from the light emitting device 1A to the second light receiving device 81-2 by receiving, at the light receiving unit 811-2 of the second light receiving device 81-2, a second irradiation beam 51-2 emitted from the second light transmitting and receiving optical element 41-2 provided in the light emitting device 1A via the optical member 20A and the imaging optical system 10A. That is, in this example, the optical wireless communication system 100A may transmit information from the light emitting device 1A to the first light receiving device 81-1 and the second light receiving device 81-2.

[0127] The control device 50A of the light irradiation device 1A may move the first light transmitting and receiving optical element 41-1 so that the irradiation beam 51 emitted from the imaging optical system 10a via the optical member 20a from the first light transmitting and receiving optical element 41-1 is incident on the first light receiving unit 811-1 (i.e., may control the position changing device 40A) based on the position of a characteristic location of the first light receiving device 81-1 as the first object (for example, a marker placed on the first light receiving device 81-1) on the image acquired by the imaging device 30A, which is identified by the above-mentioned image processing, and the positional relationship between the characteristic location of the first light receiving device 81-1 and the first light receiving unit 811-1. The control device 50A may move the second light-transmitting and receiving optical element 41-2 so that the irradiation beam 51 emitted from the imaging optical system 10a via the optical member 20a from the second light-transmitting and receiving optical element 41-2 is incident on the second light-receiving unit 811-2 (i.e., may control the position change device 40A) based on the position of a characteristic location of the second light-receiving device 81-2 as the second object (for example, a marker placed on the second light-receiving device 81-2) on the image acquired by the imaging device 30A, which is identified by the above-mentioned image processing, and the positional relationship between the characteristic location of the second light-receiving device 81-2 and the second light-receiving unit 811-2. Furthermore, based on the characteristic locations of the first light receiving device 81-1 and the second light receiving device 81-2 on the image acquired by the imaging device 30A, which have been identified by the above-mentioned image processing, the control device 50A may move the first light transmitting and receiving optical element 41-1 so that the irradiation beam 51 emitted from the imaging optical system 10a via the optical member 20a from the first light transmitting and receiving optical element 41-1 is incident on the first light receiving unit 811-1, and may move the second light transmitting and receiving optical element 41-2 so that the irradiation beam 51 emitted from the imaging optical system 10a via the optical member 20a from the second light transmitting and receiving optical element 41-2 is incident on the second light receiving unit 811-2.

[0128] Even if at least one of the positional relationships between the light irradiation device 1A and the first light receiving device 81-1 and the positional relationship between the light irradiation device 1A and the second light receiving device 81-2 changes, the control device 1A can continue the optical wireless communication from the light irradiation device 1A to the first light receiving device 81-1 and the optical wireless communication from the light irradiation device 1A to the second light receiving device 81-2 by the above-mentioned processing and control. Note that the description of the processing and control of the control device 1A will be omitted as it overlaps with the above description.

[0129] At least one of the light emitting device 1A, the first light receiving device 81-1, and the second light receiving device 81-2 may be installed on the movable body, and the movable body may move to change at least one of the positional relationship between the light emitting device 1A and the first light receiving device 81-1 and the positional relationship between the light emitting device 1A and the second light receiving device 81-2. The optical wireless communication system 100A may include two or more light emitting devices 1. For example, when two light emitting devices 1 (referred to as the first light emitting device 1A-1 and the second light emitting device 1A-2) are included, optical wireless communication may be performed from the first light emitting device 1A-1 to the first light receiving device 81-1, and optical wireless communication may be performed from the second light emitting device 1A-2 to the second light receiving device 81-2. The optical wireless communication system 100A may include three or more light receiving devices 81. In this case, optical wireless communication may be performed from the light emitting device 1A to each of the three or more light receiving devices 81. The light irradiation device 1A may have three or more light generating devices 60A. The optical wireless communication system 100A may have three or more light irradiation devices 1.

[0130] Next, an example of a case where the optical wireless communication system 100A includes a light emitting device 1 and multiple light transmitting devices 82 will be described. As an example, a case where the light emitting system 100A includes a light emitting device 1A, a first light transmitting device 82-1 as an object (first object), and a second light transmitting device 82-2 as an object (second object) will be described. When the optical wireless communication system 100A includes a light emitting device 1A and multiple light transmitting devices 82, the light emitting device 1A may include multiple light generating devices 60A in the same manner as described above, depending on the number of light transmitting devices 82 as objects to receive light. In this case, the light emitting device 1A can be considered to have multiple light receiving units.

[0131] For example, if the optical wireless communication system 100A includes two light transmitting devices 82 (a first light transmitting device 82-1 and a second light transmitting device 82-2), the light irradiating device 1A may receive light (referred to as a first incident beam 52-1) emitted from the first light transmitting device 82-1 for optical wireless communication with the light irradiating device 1A at the first communication board 62A-1 via the imaging optical system 10A, the optical member 20A, the first light transmitting and receiving optical element 41A-1, and the first optical fiber 61-1. Also, the light irradiating device 1A may receive light (referred to as a second incident beam 52-2) emitted from the second light transmitting device 82-2 for optical wireless communication with the light irradiating device 1A at the second communication board 62A-2 via the imaging optical system 10A, the optical member 20A, the second light transmitting and receiving optical element 41A-2, and the second optical fiber 61-2.

[0132] The first incident beam 52-1 and the second incident beam 52-2 may have different optical conditions. For example, the optical conditions include at least one of wavelength, frequency, phase, and polarization state. The light irradiation device 1A may receive the first incident beam 52-1 and the second incident beam 52-2 using a common communication board 62A. The light irradiation device 1A may be configured without the configuration for irradiating the irradiation beam 51. For example, at least one of the light transmitting and receiving optical elements 41-1 and 41-2 may be the above-mentioned light receiving optical element (i.e., the light receiving unit).

[0133] The position changing device 40A moves the first light transmitting and receiving optical element 41-1 and the second light transmitting and receiving optical element 41-2 individually in a direction intersecting the optical axis 111a. For example, the position changing device 40A may include a drive device that moves the first light transmitting and receiving optical element 41-1 in a direction intersecting the optical axis 111a, and a drive device that moves the second light transmitting and receiving optical element 41-2 in a direction intersecting the optical axis 111a. The position changing device 40A may also move the first light transmitting and receiving optical element 41-1 and the second light transmitting and receiving optical element 41-2 together in a direction intersecting the optical axis 111a.

[0134] The first light-transmitting device 82-1 may include a first light-transmitting unit 821-1, and the second light-transmitting device 82-2 may include a second light-transmitting unit 821-2. The first light-transmitting device 82-1 and the second light-transmitting device 82-2 may each be provided with the characteristic location described above. The characteristic location provided on the first light-transmitting device 82-1 and the characteristic location provided on the second light-transmitting device 82-2 may be distinguishable. For example, the characteristic location provided on the first light-transmitting device 82-1 and the characteristic location provided on the second light-transmitting device 82-2 may be markers with different shapes. In this case, the control device 50A may distinguishably identify the positions of the characteristic locations provided on the first light-transmitting device 82-1 and the second light-transmitting device 82-2 based on the recognition results of the respective characteristic locations provided on the two light-transmitting devices 82 on the image acquired by the imaging device 30A. The positional relationship between the characteristic features of the first light-transmitting device 82-1 and the first light-transmitting unit 821-1 of the first light-transmitting device 82-1 may be known. The positional relationship between the characteristic features of the second light-transmitting device 82-2 and the second light-transmitting unit 821-2 of the second light-transmitting device 82-2 may be known.

[0135] The optical wireless communication system 100A may perform optical wireless communication from the first light transmitting device 82-1 to the light irradiating device 1A by receiving the first incident beam 52-1 emitted from the first light transmitting unit 821-1 of the first light transmitting device 82-1 at the first communication board 62A-1 via the imaging optical system 10A, the optical member 20A, and the first light transmitting and receiving optical element 41-1 provided in the light irradiating device 1A. Also, the optical wireless communication system 100A may perform optical wireless communication from the second light transmitting device 82-2 to the light irradiating device 1A by receiving the second incident beam 52-2 emitted from the second light transmitting unit 821-2 of the second light transmitting device 82-2 at the second communication board 62A-2 via the imaging optical system 10A, the optical member 20A, and the second light transmitting and receiving optical element 41-2 provided in the light irradiating device 1A. That is, in this example, the optical wireless communication system 100A may transmit information from the first light transmitting device 82-1 and the second light transmitting device 82-2 to the light irradiation device 1A.

[0136] The control device 50A may move the first light-transmitting and receiving optical element 41-1 so that the first incident beam 52-1 emitted from the first light-transmitting unit 821-1 is incident on the first light-transmitting and receiving optical element 41-1 (first communication board 62A-1) based on the position of a characteristic part of the first light-transmitting device 82-1 as the first object (for example, a marker placed on the first light-transmitting device 82-1) on the image acquired by the imaging device 30A, which is identified by the above-mentioned image processing, and the positional relationship between the characteristic part of the first light-transmitting device 82-1 and the first light-transmitting unit 821-1 of the first light-transmitting device 82-1. The control device 50A may move the second light-transmitting and receiving optical element 41-2 so that the second incident beam 52-2 emitted from the second light-transmitting unit 821-2 is incident on the second light-transmitting and receiving optical element 41-2 (second communication board 62A-2) based on the position of a characteristic part of the second light-transmitting device 82-2 as the second object (for example, a marker placed on the second light-transmitting device 82-2) on the image acquired by the imaging device 30A, which is identified by the above-mentioned image processing, and the positional relationship between the characteristic part of the second light-transmitting device 82-2 and the second light-transmitting unit 821-2 of the second light-transmitting device 82-2. Furthermore, based on the characteristic locations of the first light-transmitting device 82-1 and the second light-transmitting device 82-2 on the image acquired by the imaging device 30A, which have been identified by the image processing described above, the control device 50A may move the first light-transmitting and receiving optical element 41-1 so that the incident beam 52-1 emitted from the first light-transmitting device 82-1 is incident on the first light-transmitting and receiving optical element 41-1 (first communication board 62A-1), and may move the second light-transmitting and receiving optical element 41-2 so that the incident beam 52-2 emitted from the second light-transmitting device 82-2 is incident on the second light-transmitting and receiving optical element 41-2 (second communication board 62A-2).

[0137] Even if at least one of the positional relationships between the light irradiation device 1A and the first light transmitting device 82-1 and the positional relationship between the light irradiation device 1A and the second light transmitting device 82-2 changes, the control device 1A can continue the optical wireless communication from the first light transmitting device 82-1 to the light irradiation device 1A and the optical wireless communication from the second light transmitting device 82-2 to the light irradiation device 1A by the above-mentioned processing and control. Note that a description of the processing and control of the control device 1A will be omitted as it overlaps with the above description.

[0138] At least one of the light irradiation device 1A, the first light transmitting device 82-1, and the second light transmitting device 82-2 may be installed on the movable body, and the movable body may move to change at least one of the positional relationship between the light irradiation device 1A and the first light transmitting device 82-1 and the positional relationship between the light irradiation device 1A and the second light transmitting device 82-2. The optical wireless communication system 100A may include two or more light irradiation devices 1. For example, when two light irradiation devices 1 are included, optical wireless communication may be performed from the first light transmitting device 82-1 to the first light irradiation device 1A-1, and optical wireless communication may be performed from the second light transmitting device 82-2 to the second light irradiation device 1A-2. The optical wireless communication system 100A may include three or more light transmitting devices 82. In this case, optical wireless communication may be performed from each of the three or more light transmitting devices 82 to the light irradiation device 1. The light irradiation device 1A may include three or more light generating devices 60A. The optical wireless communication system 100A may include three or more light irradiation devices 1.

[0139] Next, an example of an optical wireless communication system 100A including a light emitting device 1 and multiple light transmitting and receiving devices 82 will be described. As an example, a case will be described in which the light emitting system 100A includes a light emitting device 1A, a first light transmitting and receiving device 83-1 as an object (first object), and a second light transmitting and receiving device 83-2 as an object (second object). When the optical wireless communication system 100A includes a light emitting device 1A and multiple light transmitting and receiving devices 83, the light emitting device 1A may include multiple light generating devices 60A in the same manner as described above, depending on the number of light transmitting and receiving devices 83 as objects to be irradiated and received. In this case, the light emitting device 1A can be considered to have multiple light emitting units and multiple light receiving units.

[0140] For example, if the optical wireless communication system 100A includes two light transmitting and receiving devices 83 (a first light transmitting and receiving device 83-1 and a second light transmitting and receiving device 83-2), the light irradiation device 1A may emit a first irradiation beam 51-1 generated by a first communication board 62A-1 from the imaging optical system 10A, and may receive a first incident beam 52-1 emitted from the first light transmitting and receiving device 83-1 for optical wireless communication with the light irradiation device 1A by a first light transmitting and receiving optical element 41A-1 (first communication board 62A-1) via the imaging optical system 10A. In addition, the light irradiation device 1A may emit the second irradiation beam 51-2 generated by the second communication board 62A-2 from the imaging optical system 10A, and may receive the second incident beam 52-2 emitted from the second light transmitting and receiving device 83-2 for optical wireless communication with the light irradiation device 1A by the second light transmitting and receiving optical element 41A-2 (second communication board 62A-2) via the imaging optical system 10A.

[0141] The first irradiation beam 51-1 and the second irradiation beam 51-2 may have different optical conditions. The second incident beam 52-1 and the second incident beam 52-2 may have different optical conditions. The first irradiation beam 51-1 and the first incident beam 52-1 may have the same optical conditions. The second irradiation beam 51-2 and the second incident beam 52-2 may have the same optical conditions. For example, the optical conditions include at least one of wavelength, frequency, phase, and polarization state. The light irradiation device 1A may generate the first irradiation beam 51-1 and the second irradiation beam 51-2 using a common communication board 62A. The light irradiation device 1A may receive the first incident beam 52-1 and the second incident beam 52-2 using a common communication board 62A.

[0142] The position changing device 40A moves the first light transmitting and receiving optical element 41A-1 and the second light transmitting and receiving optical element 41A-2 individually in a direction intersecting the optical axis 111a. For example, the position changing device 40A may include a drive device that moves the first light transmitting and receiving optical element 41A-1 in a direction intersecting the optical axis 111a, and a drive device that moves the second light transmitting and receiving optical element 41A-2 in a direction intersecting the optical axis 111a. The position changing device 40A may also move the first light transmitting and receiving optical element 41A-1 and the second light transmitting and receiving optical element 41A-2 together in a direction intersecting the optical axis 111a.

[0143] The first light transmitting and receiving device 83-1 may include at least one of a first light receiving unit 831-1 and a first light transmitting unit 832-1, and the second light transmitting and receiving device 83-2 may include at least one of a second light receiving unit 831-2 and a second light transmitting unit 832-2. The first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 may each be provided with the above-described characteristic location. The characteristic location provided on the first light transmitting and receiving device 83-1 and the characteristic location provided on the second light transmitting and receiving device 83-2 may be distinguishable. For example, the characteristic location provided on the first light transmitting and receiving device 83-1 and the characteristic location provided on the second light transmitting and receiving device 83-2 may be markers with different shapes. In this case, the control device 50A may distinguish and identify the positions of the characteristic locations provided on the first light-transmitting and receiving device 83-1 and the second light-transmitting and receiving device 83-2 based on the recognition results of each characteristic location provided on the two light-transmitting and receiving devices 83 on the image acquired by the imaging device 30A.

[0144] The positional relationship between the characteristic location of the first light transmitting and receiving device 83-1 and at least one of the first light receiving unit 831-1 and the first light transmitting unit 832-1 of the first light transmitting and receiving device 83-1 may be known. The positional relationship between the characteristic location of the second light transmitting and receiving device 83-2 and at least one of the second light receiving unit 831-2 and the second light transmitting unit 832-2 of the second light transmitting and receiving device 83-2 may be known.

[0145] The light irradiation system 100A may perform optical wireless communication between the light irradiation device 1A and the first light transmitting and receiving device 83-1 by irradiating a first irradiation beam 51-1 emitted from a first light transmitting and receiving optical element 41A-1 provided in the light irradiation device 1A via an optical member 20A and an imaging optical system 10A onto a first light receiving unit 831-1 of the first light transmitting and receiving device 83-1, and receiving a first incident beam 52-1 from a first light transmitting unit 832-1 of the first light transmitting and receiving device 83-1 via the imaging optical system 10A, optical member 20A, and first light transmitting and receiving optical element 41A-1 provided in the light irradiation device 1A at a first communication board 62A-1.

[0146] Furthermore, the light irradiation system 100A may irradiate the second irradiation beam 51-2 emitted from the second light transmitting and receiving optical element 41A-2 provided in the light irradiation device 1A via the optical member 20A and the imaging optical system 10A onto the second light receiving unit 831-2 of the second light transmitting and receiving device 83-2, and receive the second incident beam 52-2 from the second light transmitting unit 832-2 of the second light transmitting and receiving device 83-2 via the imaging optical system 10A, the optical member 20A, and the second light transmitting and receiving optical element 41A-2 provided in the light irradiation device 1A at the second communication board 62A-2. That is, in this example, the optical wireless communication system 100A may transmit and receive information between the light irradiation device 1A and the first light transmitting and receiving device 83-1, or may transmit and receive information between the light irradiation device 1A and the second light transmitting and receiving device 83-2.

[0147] For example, if the first light receiving unit 831-1 and the first light transmitting unit 832-1 of the first light transmitting and receiving device 83-1 are arranged adjacent to or close to each other, the control device 50A may move the first light transmitting and receiving optical element 41A-1 so that the first irradiation beam 51-1 emitted from the first light transmitting and receiving optical element 41A-1 through the optical member 20A and the imaging optical system 10A is incident on the first light receiving unit 831-1, based on the position of a characteristic feature of the first light transmitting and receiving device 83-1 (e.g., a marker arranged on the first light transmitting and receiving device 83-1) on the image acquired by the imaging device 30A identified by the image processing described above and the positional relationship between the characteristic feature of the first light transmitting and receiving device 83-1 and the first light receiving unit 831-1. Here, the first irradiation beam 51-1 from the first light transmitting and receiving unit 832-1 becomes a spread-out light beam because it is diffused to a certain extent depending on the distance from the first light transmitting unit 832-1. Therefore, even if the control device 50A moves the first light-transmitting and receiving optical element 41A-1 so that the first irradiation beam 51-1 is incident on the first light-receiving unit 831-1, the first incident beam 52-1 from the first light-transmitting unit 832-1 enters the imaging optical system 10A, passes through the optical member 20A, and then enters the moved first light-transmitting and receiving optical element 41A-1 (i.e., enters the first communication board 62A-1).

[0148] Furthermore, the control device 50A may control the position changing device 40A so that the first incident beam 52-1 from the first light transmitting unit 832-1 is incident on the first light transmitting and receiving optical element 41A-1 based on the position of the characteristic part of the first light transmitting and receiving device 83-1 as an object on the image acquired by the imaging device 30A, identified by the above-mentioned image processing, and the positional relationship between the characteristic part of the first light transmitting and receiving device 83-1 and the first light transmitting unit 832-1 of the first light transmitting and receiving device 83-1.

[0149] Furthermore, when the positional relationship between the light irradiation device 1A and the first light transmitting and receiving device 83-1 changes, similar to the processing and control described above, the control device 50A may perform imaging using the imaging device 30A at a predetermined frame rate, and each time an image is acquired, the position of a characteristic part of the first light transmitting and receiving device 83-1 on the acquired image may be identified using the image processing described above, and the position changing device 40A may be controlled so that the first irradiation beam 51-1 from the light irradiation device 1A is incident on the first light receiving unit 831-1 (or so that the first incident beam 52-1 from the first light transmitting unit 832-1 is incident on the first light transmitting and receiving optical element 41A-1).

[0150] The control device 50A may detect the displacement of a characteristic feature of the first light transmitting and receiving device 83-1 on the image by identifying the position of the characteristic feature of the first light transmitting and receiving device 83-1 using the image processing described above for each image acquired at a predetermined frame rate. Based on the displacement of the characteristic feature on the image, the control device 50A may then control the position changing device 40A so that the first irradiation beam 51-1 from the light emitting device 1A is incident on the first light receiving unit 831-1 (or so that the first incident beam 52-1 from the first light transmitting unit 832-1 is incident on the first light transmitting and receiving optical element 41A-1). The above processing and control by the control device 50A allows the light emitting device 1A and the first light transmitting and receiving device 83-1 to continue bidirectional optical wireless communication even if the positional relationship between the light emitting device 1A and the first light transmitting and receiving device 83-1 changes.

[0151] As described above, the first light-transmitting and receiving optical system element 41A-1 may be divided into a light-transmitting optical element (which may be referred to as a first light-transmitting optical element in this case) and a light-receiving optical element (which may be referred to as a first light-receiving optical element in this case). As described above, the position changing device 40A may include a drive device that moves the light-transmitting optical element and a drive device that moves the light-receiving optical element. In this case, the control device 50A may move the light-transmitting optical element so that the first irradiation beam 51-1 emitted from the imaging optical system 10A via the optical member 20A is incident on the first light-receiving unit 831-1, based on the position of the characteristic location of the first light-transmitting and receiving device 83-1 on the image acquired by the imaging device 30A, which is identified by the image processing described above, and the positional relationship between the characteristic location of the first light-transmitting and receiving device 83-1 and the first light-receiving unit 831-1. The control device 50A may move the light-receiving optical element so that the first incident beam 52-1 from the first light-transmitting / receiving device 83-1 is incident on the light-receiving optical element via the imaging optical system 10A and the optical member 20A, based on the position of the characteristic location of the first light-transmitting / receiving device 83-1 on the image acquired by the imaging device 30A, which are identified by the image processing described above, and the positional relationship between the characteristic location of the first light-transmitting / receiving device 83-1 and the first light-transmitting unit 832-1. By the processing and control of the control device 50A described above, even if the first light-receiving unit 831-1 and the first light-transmitting unit 832-1 of the first light-transmitting / receiving device 83-1 are not arranged adjacent to or close to each other, the light irradiation device 1A and the first light-transmitting / receiving device 83-1 can perform bidirectional optical wireless communication.

[0152] In addition, when the positional relationship between the light irradiation device 1A and the first light transmitting and receiving device 83-1 changes, the control device 50A may perform imaging using the imaging device 30A at a predetermined frame rate and, for each acquired image, identify the position of a characteristic feature of the first light transmitting and receiving device 83-1 using the image processing described above to detect the displacement of the characteristic feature on the image. Then, based on the displacement of the characteristic feature on the image, the control device 50A may move the light transmitting optical element so that the first irradiation beam 51-1 emitted from the imaging optical system 10A is incident on the first light receiving unit 832-1, or may move the light receiving optical element so that the first incident beam 52-1 from the first light transmitting unit 832-1 is incident on the light receiving optical element via the imaging optical system 10A. Through the above processing and control by the control device 50A, even if the positional relationship between the light irradiation device 1A and the first light transmitting and receiving device 83-1 changes, the light irradiation device 1A and the first light transmitting and receiving device 83-1 can continue bidirectional optical wireless communication.

[0153] At least one of the light irradiation device 1A and the first light transmitting and receiving device 83-1 may be installed on the above-mentioned movable body, and the positional relationship between the light irradiation device 1A and the first light transmitting and receiving device 83-1 may be changed by moving the movable body. Note that the processing and control of the control device 50A when the light irradiation device 1A and the second light transmitting and receiving device 83-2 communicate optically wirelessly is similar to the processing and control of the control device 50A when the light irradiation device 1A and the first light transmitting and receiving device 83-1 communicate optically wirelessly (that is, the processing and control when the control target of the control device 50A in the above description is replaced from the first light transmitting and receiving optical element 41A-1 to the second light transmitting and receiving optical element 41A-2, and the first light transmitting and receiving device 83-1 is replaced by the second light transmitting and receiving device 83-2), and therefore a description thereof will be omitted.

[0154] The optical wireless communication system 100A may include two or more light irradiation devices 1. For example, when two light irradiation devices 1 are included, optical wireless communication may be performed between a first light irradiation device 1A-1 as the first light irradiation device and a first light transmitting and receiving device 83-1, and optical wireless communication may be performed between a second light irradiation device 1A-2 as the second light irradiation device and a second light transmitting and receiving device 83-2. The optical wireless communication system 100A may include three or more light transmitting and receiving devices 83. In this case, optical wireless communication may be performed between each of the three or more light transmitting and receiving devices 83 and the light irradiation device 1A. The light irradiation device 1A may include three or more light generating devices 60A. The optical wireless communication system 100A may include three or more light irradiation devices 1.

[0155] As described above, according to this embodiment, the light irradiation device 1 includes the imaging optical system 10, the optical element 20, the image capturing device 30, the position changing device 40, and the control device 50, and thereby irradiates an object with the irradiation beam 51 from the light generating device 60. The light irradiation device 1 includes the optical element 20, and thereby emits light incident via the imaging optical system 10 toward the image plane 210 of the imaging optical system 10, and also emits the irradiation beam 51 from the light generating device 60, which is incident via a conjugate plane 220 conjugate to the image plane 210, toward the imaging optical system 10. The light irradiation device 1 includes the image capturing device 30, and thereby captures at least a portion of the image of the object formed on the image plane 210 by the imaging optical system 10. The light irradiation device 1 includes the position changing device 40, and thereby changes the position of the irradiation beam 51 from the light generating device 60 on the conjugate plane 220, thereby changing the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10. The light irradiation device 1 includes a control device 50, which controls the position changing device 40 based on the image capture result of the image capture device 30, and irradiates at least a part of the object with the irradiation beam 51 emitted from the imaging optical system 10. Therefore, according to this embodiment, the irradiation beam 51 can be irradiated at a position corresponding to the position of the object.

[0156] Furthermore, according to the above-described embodiment, the imaging optical system 10 is telecentric on the side of the conjugate plane 220. Therefore, according to this embodiment, it is not necessary to adjust the angle of the irradiation beam 51 emitted from the light-transmitting and receiving optical element 41, and the light-transmitting and receiving optical element 41 can be easily controlled.

[0157] Furthermore, according to the above-described embodiment, the maximum angle of view of the imaging optical system 10 is equal to or greater than 170°. Therefore, the light irradiation device 1 can irradiate the irradiation beam 51 over a wide range.

[0158] Furthermore, according to the above-described embodiment, the imaging optical system 10 forms a reduced image of the object on the image plane 210. That is, the light irradiation device 1 can transmit and receive light at a field angle corresponding to the magnification of the imaging optical system 10 within the range in which the light transmitting and receiving optical element 41 can move. Therefore, the light irradiation device 1 can receive light at a wide field angle and transmit light at a wide field angle. It is also possible to increase the amount of change in the light transmission direction relative to the movement distance of the light transmitting and receiving optical element 41. Therefore, the light transmission direction can be changed quickly. Furthermore, even if the incident direction of light entering the light irradiation device 1 is changed significantly, the movement distance of the light transmitting and receiving optical element 41 can be reduced. Therefore, even if the incident direction changes significantly in a short period of time, it is easy to follow the change.

[0159] Furthermore, according to the above-described embodiment, the control device 50 controls the position changing device 40 based on the characteristic location of the object detected based on the image capturing result captured by the image capturing device 30. Therefore, the light irradiation device 1 can easily track the object even if it moves.

[0160] Furthermore, according to the above-described embodiment, the imaging device 30 has a plurality of pixels. By having a plurality of pixels, the imaging device 30 can accurately determine the position of an object.

[0161] Furthermore, according to the above-described embodiment, the light irradiation device 1 includes a light emitting unit (light transmitting and receiving optical element 41) to emit the irradiation beam 51 toward the optical member 20, and includes a position changing device 40 to move the light emitting unit in a direction intersecting with the optical axis 111 on the light emitting unit side of the imaging optical system 10. That is, the light irradiation device 1 changes the irradiation position of the irradiation beam 51 by moving the position of the light transmitting and receiving optical element 41. Therefore, according to this embodiment, the light irradiation device 1 can easily change the position at which the irradiation beam 51 is irradiated, and can easily track an object.

[0162] Furthermore, according to the above-described embodiment, the light receiving unit 831 of the light receiving device 81 is an example of an object onto which the light emitting device 1 irradiates the irradiation beam 51. That is, the irradiation beam 51 is irradiated onto the light receiving unit 831. Therefore, the light emitting device 1 can perform optical wireless communication with the light receiving device 81.

[0163] Furthermore, according to the above-described embodiment, the light irradiation device 1 includes the light receiving unit 120, and receives the incident beam 52, which is emitted from the light emitting unit (light transmitting unit) of the light transmitting device 82 as an object and enters the imaging optical system 10, via the optical member 20. Therefore, the light irradiation device 1 can easily perform optical wireless communication with the light transmitting device 82.

[0164] Furthermore, according to the above-described embodiment, the light receiving unit 120 receives the incident beam 52 via the conjugate plane 220. Therefore, according to this embodiment, by moving the light receiving unit 120 to the position imaged by the imaging device 30, the position of the light receiving unit 120 can be aligned with the position where the incident beam 52 is incident.

[0165] Furthermore, according to the embodiment described above, the incident beam 52 is an optical beam for optically communicating wirelessly between the light irradiation device 1 and the light transmitting device 82. Therefore, according to the present embodiment, the light irradiation device 1 can communicate optically wirelessly with the light transmitting device 82.

[0166] Furthermore, according to the above-described embodiment, the light transmitting device 82 is an example of a light transmitting and receiving device 83 including a light receiving unit 831, and the incident beam 52 is emitted from the light transmitting and receiving device 83, and the irradiation beam 51 is irradiated onto the light receiving unit 831. The incident beam 52 and the irradiation beam 51 are each an optical beam for optically communicating wirelessly with the light transmitting and receiving device 83. Therefore, according to this embodiment, the light irradiation device 1 can communicate optically wirelessly with the light transmitting device 82.

[0167] Furthermore, according to the above-described embodiment, an image of at least a portion of a second object different from the first object is formed on the image plane 210 by the imaging optical system 10, and the imaging device 30 captures an image of at least a portion of the first object and an image of at least a portion of the second object. That is, the imaging device 30 captures images of two objects. The light irradiation device 1 emits a first irradiation beam to the first object based on the position of the imaged first object, and emits a second irradiation beam to the second object based on the position of the imaged second object. Therefore, the light irradiation device 1 can simultaneously irradiate multiple light receiving devices 81 with irradiation beams 51.

[0168] Furthermore, according to the above-described embodiment, the first object is at least a part of the first light receiving device 81-1, and the second object is at least a part of the second light receiving device 81-2. The first irradiation beam 51-1 is irradiated onto the light receiving section (first light receiving section 811-1) of the first light receiving device 81-1, and the second irradiation beam 51-2 is irradiated onto the light receiving section (second light receiving section 811-2) of the second light receiving device 81-2. Therefore, the light irradiation device 1 can irradiate the irradiation beam 51 onto multiple light receiving devices 81 simultaneously.

[0169] Furthermore, according to the above-described embodiment, the light irradiation device 1 further includes a light receiving unit, and thereby receives the first incident beam 52-1 and the second incident beam 52-2 via the optical member 20. Therefore, the light irradiation device 1 can simultaneously receive the incident beams 52 irradiated from the plurality of light transmitting devices 82.

[0170] Furthermore, according to the above-described embodiment, the first light transmitting device 82-1 may be a first light transmitting and receiving device 83-1 including a light receiving unit 831-1, and the second light transmitting device 82-2 may be a second light transmitting and receiving device 83-2 including a light receiving unit 831-2. Therefore, according to this embodiment, the light irradiation device 1 can communicate optically wirelessly with a plurality of light transmitting and receiving devices 83.

[0171] Furthermore, according to the above-described embodiment, in the optical wireless communication system 100A, the light emitting device 1 receives the irradiation beam 51 from the light emitting device 1 at the light receiving section 811 of the light receiving device 81, thereby enabling wireless optical communication between the light emitting device 1 and the light receiving device 81. Therefore, according to the present embodiment, in the optical wireless communication system 100A, the light emitting device 1 can transmit information to the light receiving device 81.

[0172] Furthermore, according to the above-described embodiment, in the optical wireless communication system 100A, the incident beam 52 from the light transmitting device 82 is received by the light receiving unit of the light emitting device 1, thereby enabling wireless optical communication between the light transmitting device 82 and the light emitting device 1. Therefore, according to this embodiment, in the optical wireless communication system 100A, the light emitting device 1 can receive information from the light transmitting device 82.

[0173] Furthermore, according to the above-described embodiment, in the optical wireless communication system 100A, the light emitting device 1 irradiates the light receiving unit 831 of the light transmitting and receiving device 83 with the irradiation beam 51, and the light receiving unit of the light emitting device 1 receives the incident beam 52 from the light transmitting and receiving device 83, thereby enabling optical wireless communication between the light emitting device 1 and the light transmitting and receiving device 83. Therefore, according to this embodiment, in the optical wireless communication system 100A, the light emitting device 1 can transmit and receive information to and from the light transmitting and receiving device 83.

[0174] Furthermore, according to the above-described embodiment, the optical wireless communication system 100A receives the first irradiation beam 51-1 from the light emitting device 1 at the light receiving section (first light receiving section 811-1) of the first light receiving device 81-1, and receives the second irradiation beam 51-2 at the light receiving section (second light receiving section 811-2) of the second light receiving device 81-2. Therefore, according to this embodiment, the optical wireless communication system 100A can transmit information from the light emitting device 1 to multiple light receiving devices 81.

[0175] Furthermore, according to the above-described embodiment, the light receiving unit of the light irradiation device 1 receives the first incident beam 52-1 from the first light transmitting device 82-1 and the second incident beam 52-2 from the second light transmitting device 82-2, thereby wirelessly communicating optically with the first light transmitting device 82-1 and the second light transmitting device 82-2. Therefore, according to this embodiment, the light irradiation device 1 can simultaneously receive information transmitted from a plurality of light transmitting devices 82.

[0176] Furthermore, according to the above-described embodiment, the light irradiation device 1 irradiates the light receiving unit (first light receiving unit 831-1) of the first light transmitting and receiving device 83-1 with the first irradiation beam 51-1, and irradiates the light receiving unit (second light receiving unit 831-2) of the second light transmitting and receiving device 83-2 with the second irradiation beam 51-2. Therefore, according to this embodiment, the light irradiation device 1 can simultaneously transmit information to multiple light transmitting and receiving devices 83. Note that, in this embodiment, at least one of the light of the irradiation beam 51 and the incident beam 52 is not limited to light for optical wireless communication. For example, at least one of the light of the irradiation beam 51 and the incident beam 52 may be light for optical wireless power transmission. The wavelength of the light for optical wireless power transmission may be in the infrared wavelength band, the ultraviolet wavelength band, or the visible light wavelength band. The output of the light for optical wireless power transmission may be several watts, several tens of watts, or several kilowatts. As an example, when the irradiation beam 51 is light for optical wireless power supply, the light irradiation device 1A may supply power to a target device to be optically powered wirelessly (for example, at least one device of the light irradiation device 1B, the light receiving device 82, and the light transmitting and receiving device 83) by irradiating the irradiation beam 51 to the target device through processing and control by the above-mentioned control device 50. The light irradiation device 1A may also be referred to as a power supply device.

[0177] Second Embodiment FIG. 8 is a schematic diagram illustrating a light irradiation device according to a second embodiment. A light irradiation device 1C according to the second embodiment will be described with reference to the same figure. The light irradiation device 1C differs from the light irradiation device 1 in that it includes an optical system 70. The light irradiation device 1C also differs from the light irradiation device 1 in that it includes a position changer 40C instead of the position changer 40. The light irradiation device 1C may be provided with the above-described characteristic features. The light irradiation device 1C may be mounted on the above-described movable body. In the description of the light irradiation device 1C, components similar to those of the light irradiation device 1 are denoted by the same reference numerals, and their description may be omitted. FIG. 8 does not illustrate the control device 50 and part of the light generator 6 (optical fiber 61, communication board 62). In this embodiment, the light irradiation system 100 may perform optical wireless communication.

[0178] The optical system 70 may be installed between the light transmitting and receiving optical element 41 and the optical member 20. By installing the optical system 70, as shown in FIG. 8 , a first conjugate plane 221 and a second conjugate plane 222 are formed as the conjugate plane 220. As an example, the first conjugate plane 221 may be formed at the same position as the above-mentioned conjugate plane 220, or may be formed at a different position. The second conjugate plane 222 is formed between the light transmitting and receiving optical element 41 and the optical system 70 and is a plane conjugate to the first conjugate plane 221. The position changing device 40C moves the light transmitting and receiving optical element 41 to change the position of the irradiation beam 51 from the light generating device 60 on the second conjugate plane 222. It can also be said that the second conjugate plane 222 is formed between the position changing device 40C and the optical system 70.

[0179] The irradiation beam 51 from the light transmitting and receiving optical element 41 (light generating device 60) is incident on the optical system 70 via the second conjugate plane 222. Then, the irradiation beam 51 emitted from the optical system 70 is incident on the optical member 20 via the first conjugate plane 221. It can also be said that the irradiation beam 51 from the light transmitting and receiving optical element 41 is incident on the optical member 20 via the conjugate plane 220.

[0180] The position changing device 40C may change the position of the irradiation beam 51 on the second conjugate plane 222 by changing the position of the light transmitting and receiving optical element 41 on the x-z plane. Note that, since the second conjugate plane 222 is the conjugate plane 220, it can also be said that the position changing device 40C changes the position of the irradiation beam 51 on the conjugate plane 220. The position changing device 40C may change the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10. Specifically, the position changing device 40C may be a driving device for changing the position of the irradiation beam 51 from the light transmitting and receiving optical element 41 on the second conjugate plane 222. The position changing device 40C may change the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 by changing the position of the irradiation beam 51 from the light transmitting and receiving optical element 41 on the second conjugate plane 222.

[0181] When the position of the irradiation beam 51 from the light transmitting and receiving optical element 41 changes on the second conjugate plane 222, the position at which the irradiation beam 51 enters the imaging optical system 10 via the optical system 70 and the optical member 20 changes. As the incident position of the irradiation beam 51 from the optical member 20 side to the imaging optical system 10 changes, the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 changes. It can also be said that the position changing device 40C changes the position of the irradiation beam 51 from the light transmitting and receiving optical element 41 on the second conjugate plane 222, thereby changing the irradiation direction of the irradiation beam 51 emitted from the imaging optical system 10.

[0182] The position changing device 40C may be a drive device that moves the light transmitting and receiving optical element 41 of the light irradiation device 1C, similar to the position changing device 40. The position changing device 40C may be a drive device that moves the light generating device 60. The position changing device 40C may be a drive device that moves the light transmitting and receiving optical element 41 relative to the optical system 70, the optical member 20, the imaging optical system 10, and the imaging device 30. The position changing device 40C may be a well-known drive device such as a linear motor or a stepping motor that can move the light transmitting and receiving optical element 41. Note that the position changing device 40 may be a drive device that moves the optical system 70, the optical member 20, the imaging optical system 10, and the imaging device 30 relative to the light transmitting and receiving optical element 41.

[0183] Here, the optical axis 111 of the imaging optical system 10 from the optical element 20 to the second conjugate plane 222 (conjugate plane 220) may be referred to as the optical axis 111c, and the optical axis 111b from the optical element 20 to the image plane 210 may be referred to as the optical axis 111c. The optical axis 111c may also be referred to as the optical axis on the second conjugate plane 222 side (i.e., the conjugate plane 220 side) of the imaging optical system 10. The optical axis 111b may also be referred to as the optical axis on the image plane 210 side of the imaging optical system 10. In this case, the position changer 40C can also be said to move the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111c. The position changer 40C can also be said to move the light transmitting and receiving optical element 41 in a direction perpendicular to the optical axis 111c. The position changer 40C can also be said to move the light transmitting and receiving optical element 41 within a plane intersecting the optical axis 111c. The position changing device 40C may change the position of the irradiation beam 51 from the light transmitting and receiving optical element 41 on the second conjugate plane 222 by moving the light transmitting and receiving optical element 41 as described above. As described above, since the light transmitting and receiving optical element 41 can be considered as a light emitting portion, the optical axis 111c may also be referred to as the optical axis on the light emitting portion side of the imaging optical system 10. As described above, since the light transmitting and receiving optical element 41 can be considered as a light receiving portion, the optical axis 111c may also be referred to as the optical axis on the light receiving portion side of the imaging optical system 10. As described above, since the light transmitting and receiving optical element 41 can be considered as a light transmitting and receiving portion, the optical axis 111c may also be referred to as the optical axis on the light transmitting and receiving portion side of the imaging optical system 10.

[0184] The position changing device 40C may, for example, move the light transmitting and receiving optical element 41 in the direction of arrow 410 to move the irradiation position of the irradiation beam 51 in the direction of arrow 410C. The position changing device 40C also changes the light receiving position of the incident beam 51 emitted from the light emitting device 1C or the light transmitting device 82, which are the other party in the optical wireless communication. The light receiving position can also be referred to as the position where the incident beam 52 from the light emitting device 1C or the light transmitting device 82, which are the other party in the optical wireless communication, enters the imaging optical system 10. The light receiving position can also be referred to as the position of the light transmitting and receiving optical element 41 in a direction perpendicular to the optical axis 111c. For example, the position changing device 40C changes the light receiving position of the irradiation beam 51 by moving the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111c as described above. When the position changing device 40C moves the light transmitting and receiving optical element 41 in a direction intersecting the optical axis 111c, the optical path of the incident beam 52 from the imaging optical system 10 to the light transmitting and receiving optical element 41 changes. Changing the optical path from the imaging optical system 10 to the light transmitting and receiving optical element 41 changes the light receiving position of the incident beam 52. The position changing device 40 may change the light receiving position of the incident beam 52 by moving the light transmitting and receiving optical element 41 as described above. The position changing device 40C may change the light receiving position of the incident beam 52 by moving the entire light generating device 60 as described above. It can also be said that the position changing device 40C changes the light receiving direction of the incident beam 52 by moving the light transmitting and receiving optical element 41 as described above.

[0185] The optical system 70 may be telecentric on at least one of the light transmitting and receiving optical element 41 side and the optical member 20 side. For example, if the optical system 70 is telecentric on both the light transmitting and receiving optical element 41 side and the optical member 20 side, it is possible to easily align the position of the light transmitting and receiving optical element 41 on the x-z plane with at least a part of the object to be irradiated. The light transmitting and receiving optical element 41 side of the optical system 70 may also be referred to as the position changing device 40C side of the optical system 70. The light transmitting and receiving optical element 41 side of the optical system 70 may also be referred to as the second conjugate plane 222 side of the optical system 70. The optical member 20 side of the optical system 70 may also be referred to as the first conjugate plane 221 side of the optical system 70.

[0186] As shown in FIG. 8 , the optical system 70 installed between the first conjugate plane 221 and the second conjugate plane 222 may be a magnifying optical system. When the optical system 70 is a magnifying optical system, the optical system 70 forms a second conjugate plane 222 that is a magnified version of the first conjugate plane 221 at a predetermined magnification. When the optical system 70 is a magnifying optical system, the control device 50 of the light irradiation device 1C simply positions the light transmitting / receiving optical element 41 so that the incident position of the irradiation beam 51 on the second conjugate plane 222 magnified at a predetermined magnification is the desired incident position (i.e., the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 on the object is the desired irradiation position that allows optical communication). Therefore, the control device 50 (position changing device 40C) of the light irradiation device 40C can more precisely control the irradiation position on the object. In other words, the position changing device 40C can be replaced with a less expensive driving device with a larger positioning error. In other words, the control device 50 can be replaced with a less expensive control device with a larger control error.

[0187] Furthermore, when the optical system 70 is a magnifying optical system, a larger space can be secured on the x-z plane (for example, on the plane intersecting with the optical axis 111c of the imaging optical system 10), and therefore installation space for installing the light transmitting and receiving optical element 41 and the position changing device 40C can be secured on the plane perpendicular to the y-axis direction. Note that the optical system 70 is not limited to a magnifying optical system, and may be a reducing optical system or an 1x optical system.

[0188] Here, if the light irradiation device 1 does not include the optical system 70, there may be a case where space cannot be secured near the conjugate plane 220 of the optical member 20 for the position changer 40 to include a mechanism used to move the light transmitting and receiving optical element 41. As described above, according to this embodiment, by further including the optical system 70, the light transmitting and receiving optical element 41 and the position changer 40C can be positioned away from the optical member 20. Therefore, space can be secured for installing the light receiving optical element 41 and the position changer 40C.

[0189] The control device 50 of the light irradiation device 1C, like the control device 50 of the light irradiation device 1 of the first embodiment, may control the position change device 40C to perform optical wireless communication with the other light irradiation device 1C (i.e., may move the light transmitting and receiving optical element 41) based on the image capture result of at least a portion of the object by the imaging device 30. The control device 50 of the light irradiation device 1C, like the control device 50 of the light irradiation device 1 of the first embodiment, may control the position change device 40C to perform optical wireless communication with the other light irradiation device 1 of the first embodiment based on the image capture result of at least a portion of the object by the imaging device 30. The light irradiation device 1C is not limited to another light irradiation device 1C as an object, and may also be capable of optical wireless communication with the above-mentioned light receiving device 81, light transmitting device 82, or light transmitting and receiving device 83 as an object. Even in this case, the control device 50 of the light irradiation device 1C may perform optical wireless communication with the light receiving device 81, light transmitting device 82, or light transmitting and receiving device 83 by executing the same processing and control as the control device 50 of the light irradiation device 1 of the first embodiment. As an example, in the case of optical wireless communication with the light receiving device 83, the control device 50 of the light irradiation device 1C may control the position changing device 40C (i.e., may move the light transmitting and receiving optical element 41) so that the irradiation beam 51 from the light irradiation device 1C is incident on the light receiving unit 811 based on the position of a characteristic part of the light receiving device 81 (for example, a marker placed on the light receiving device 81) on the image acquired by the imaging device 30, which is identified by the image processing described above, and the positional relationship between the characteristic part of the light receiving device 81 and the light receiving unit 811 of the light receiving device 81. Note that, since the description of the processing and control by the control device 50 of the light irradiation device 1C overlaps with the description of the first embodiment, a description will be omitted.

[0190] Note that a light irradiation device 1C may be used instead of the light irradiation device 1A of the optical wireless communication system 100A of the first embodiment, and optical wireless communication may be performed between the light irradiation device 1C and zero or more light receiving devices 81, light transmitting devices 82, and light transmitting and receiving devices 83. Note that a description of the processing and control of the control device 50 of the light irradiation device 1C in this case will be omitted because it overlaps with the description of the first embodiment. Note that, as in the first embodiment, at least one of calibration of the imaging device 30 and calibration of the light transmitting and receiving optical element 41 may be performed. Note that, in this embodiment, at least one of the light of the irradiation beam 51 and the incident beam 52 is not limited to light for optical wireless communication. For example, at least one of the light of the irradiation beam 51 and the incident beam 52 may be light for optical wireless power transmission. The wavelength of the light for optical wireless power transmission may be in the infrared wavelength band, the ultraviolet wavelength band, or the visible light wavelength band. The output of the light for optical wireless power transmission may be several watts, several tens of watts, or several kilowatts. As an example, when the irradiation beam 51 is light for optical wireless power supply, the light irradiation device 1C may supply power to a target device to be optically powered wirelessly (for example, at least one device of the light irradiation device 1C, the light receiving device 82, and the light transmitting and receiving device 83) by irradiating the irradiation beam 51 to the target device through processing and control by the above-mentioned control device 50. The light irradiation device 1C may also be referred to as a power supply device.

[0191] [Third Embodiment] FIG. 9 is a schematic diagram illustrating the configuration of a light irradiation device according to a third embodiment. A light irradiation device 1D according to the third embodiment will be described with reference to the same figure. The light irradiation device 1D differs from the light irradiation device 1 in that it includes a position changing device 40D instead of the position changing device 40. The light irradiation device 1D also differs from the light irradiation device 1 in that it includes a light transmitting optical element 41D instead of the light transmitting and receiving optical element 41. The light irradiation device 1D also differs from the light irradiation device 1 in that it includes an imaging device 30D instead of the imaging device 30. The light irradiation device 1D also differs from the light irradiation device 1 in that it includes a focusing optical system 71 and a collimating lens 73. The light irradiation device 1D may be provided with the above-described characteristic features. The light irradiation device 1D may be installed on the above-described movable body. In the description of the light irradiation device 1D, components similar to those of the light irradiation device 1 are denoted by the same reference numerals, and description thereof may be omitted. 9, the control device 50 is omitted from the illustration. In this embodiment, the light irradiation device 1D may perform optical wireless communication.

[0192] In the above-described embodiments, the position change device 40 or 40C changes the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 by moving the light transmitting and receiving optical element 41 on the xz plane (for example, on the plane intersecting with the optical axis 111a or 111c on the conjugate plane side of the imaging optical system 10). However, since a mechanism for moving on a plane increases the size of the device, the present embodiment aims to reduce the size by eliminating the mechanism for moving on a plane.

[0193] The light-sending optical element 41D may include an optical fiber that emits the illumination beam 51 generated by the communication board 62 toward the collimating lens 73 described below. The light-sending optical element 41D may also include an existing optical component other than an optical fiber. The light-sending optical element 41D may be configured with at least one existing optical component as long as it can emit the illumination beam 51 from the light-sending optical element 41D and the communication board 62 toward the collimating lens 73. The light-sending optical element 41D may include, for example, the optical fiber 61-1 and Fresnel lens 42-1 described above. The position changing device 40D includes at least an incident angle changing member 72. The position changing device 40D changes the position of the illumination beam 51 from the light-sending optical element 41D (collimating lens 73) on the conjugate plane 220. The position changing device 40D may also include at least one existing optical component in addition to the incident angle changing member 72. It should be noted that the position changing device 40D may be any other existing device capable of changing the position on the conjugate plane 220 of the illumination beam 51 from the light sending optical element 41D.

[0194] The focusing optical system 71 is disposed on the optical path between the light-sending optical element 41D and the optical member 20. The focusing optical system 71 focuses the illumination beam 51 emitted from the light-sending optical element 41D. Specifically, the illumination beam 51 is focused on the conjugate plane 220. Focusing on the conjugate plane 220 broadly includes focusing near the conjugate plane. The focusing optical system 71 may be disposed on the conjugate plane 220 of the imaging optical system 10 or near the conjugate plane 220. For example, as shown in FIG. 9 , a light-emitting end 711 of the focusing optical system 71 on the optical member 20 side may be disposed slightly away from the conjugate plane 220 in the direction away from the optical member 20 (positive y-axis direction). The focusing optical system 71 may be, for example, an fθ lens. In this case, the fθ lens may be an optical system composed of at least one optical member. The focusing optical system 71 does not have to be an fθ lens and may have other projection characteristics. For example, the light-collecting optical system 71 may be an optical system having an equal solid angle projection characteristic or an orthogonal projection characteristic.

[0195] The collimating lens 73 converts the irradiation beam 51 (diffused light) emitted from the light transmitting / receiving optical element 41D into parallel light. The collimating lens 73 may be a single lens or may be composed of multiple lenses. The collimating lens 73 may also be composed of at least one lens and other optical members.

[0196] The incident angle changing member 72 reflects the illumination beam 51 emitted from the collimator lens 73 (i.e., the illumination beam 51 from the light transmitting and receiving optical element 41D) at an arbitrary angle, thereby making the illumination beam 51 incident on the focusing optical system 71 at an arbitrary incident angle. The incident angle changing member 72 can change the reflection angle of the incident illumination beam 51 (i.e., the exit angle from the incident angle changing member 72). The incident angle changing member 72 may include a reflecting element, and change the inclination angle of the reflecting element to change the reflection angle of the incident illumination beam 51 (the exit angle from the incident angle changing member 72). The incident angle changing member 72 may be, for example, a spatial light modulator such as a mirror array having a plurality of reflecting elements arranged two-dimensionally, the inclination angle of each reflecting element being changeable. In this case, the incident angle changing member 72 may be a DMD (Digital Mirror Device) as the spatial light modulator. The incident angle changing member 72 is not limited to a reflective type, and may be an existing transmissive spatial light modulator. Note that the incident angle changing member 72 is not limited to a spatial light modulator, and may be a galvanometer mirror (which may also be called a galvanometer scanner) or a polygon mirror (which may also be called a polygon scanner).

[0197] The incident angle of the illumination beam 51 onto the focusing optical system 71 is changed by changing the reflection angle of the illumination beam 51 (e.g., the inclination angle of the reflecting element of the incident angle changing member 72) using the incident angle changing member 72. The focusing optical system 71 focuses the incident illumination beam 51 toward the conjugate plane 220. Here, for example, if the focusing optical system 71 is an fθ lens, the focusing position on the conjugate plane 220 changes depending on the incident angle of the incident illumination beam 51. Therefore, the incident angle changing member 72 changes the position of the illumination beam 51 on the conjugate plane 220 by changing the incident angle of the illumination beam 51 onto the focusing optical system 71. Note that, as described above, by changing the position of the illumination beam 51 on the conjugate plane 220, it is possible to change the irradiation position of the illumination beam 51 emerging from the imaging optical system 10 via the optical member 20. That is, the position changing device 40D can change the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 by changing the reflection angle of the irradiation beam 51 at the incident angle changing member 72 (for example, the inclination angle of the reflecting element of the incident angle changing member 72). Therefore, the position changing device 40D can change the position of the irradiation beam 51 emitted from the light-sending optical element 41D (light generating device 6) on the conjugate plane 220, and change the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10.

[0198] As described above, the focusing optical system 71 contributes to changing the position of the illumination beam 51 on the conjugate plane 220, and therefore can be considered to be part of the position changing device 40D. Furthermore, the collimating lens 73 contributes to changing the position of the illumination beam 51 on the conjugate plane 220, and therefore can be considered to be part of the position changing device 40D. Therefore, the position changing device 40D can be considered to include at least one of the focusing optical system 71 and the collimating lens 73 in addition to the incident angle changing member 72. Furthermore, the collimating lens 73 contributes to changing the incident angle of the illumination beam 51 to the focusing optical system 73, and therefore can be considered to be part of the incident angle changing member 72. Therefore, the incident angle changing member 72 can be considered to include the collimating lens 73.

[0199] The light-emitting end 711 of the focusing optical system 71 may be disposed on the conjugate plane 220, or may be disposed slightly closer to the optical member 20 (toward the negative y-axis direction) than the conjugate plane 220. Even when the light-emitting end 711 of the focusing optical system 71 is disposed on the conjugate plane 220 or when the light-emitting end 711 is disposed slightly closer to the optical member 20 than the conjugate plane 220, the irradiation beam 51 emitted from the focusing optical system 71 can be considered to be incident on the optical member 20 via the conjugate plane 220. Therefore, even when the light-emitting end 711 of the focusing optical system 71 is disposed on the conjugate plane 220 or when the light-emitting end 711 is disposed slightly closer to the optical member 20 than the conjugate plane 220, the incident angle changing member 72 can be considered to change the position of the irradiation beam 51 on the conjugate plane 220 by changing the incident angle of the irradiation beam 51 on the focusing optical system 71.

[0200] The imaging device 30D is disposed near the image plane 210. The imaging device 30D can capture an image of at least a portion of an object (e.g., the other party's light transmitting and receiving device 83) formed on the image plane 210, and can also receive (photoelectrically convert) an incident beam 52 from the object (e.g., the other party's light transmitting and receiving device 83). The imaging device 30D may include an imaging element 32 having a plurality of pixels arranged on the imaging plane. At least some of the pixels provided in the imaging element 32 may each be a light receiving element capable of receiving light for forming an image of at least a portion of the object and receiving the incident beam 52 from the object. In this case, among the plurality of pixels provided in the imaging element 32, pixels (light receiving elements) capable of receiving light for forming an image of at least a portion of the object and the incident beam 52 from the object may be referred to as imaging pixels because they are capable of receiving light for forming an image of at least a portion of the object, or may be referred to as light receiving pixels because they are capable of receiving the incident beam 52 from the object. In this case, pixels (light-receiving pixels) capable of receiving incident beam 52 from an object receive incident beam 51 incident via image plane 210. In this case, image capture device 30D may be referred to as a light-receiving unit because it receives incident beam 52. Pixels (light-receiving pixels) capable of receiving incident beam 52 from an object of image capture element 32 of image capture device 30D may also be referred to as a light-receiving unit.

[0201] For example, the image sensor 32 may be an RGB sensor. In this case, the image capturing device 30D may capture an image of at least a portion of an object formed on the image plane 210 using a protocol and algorithm for distinguishing between light for forming an image of at least a portion of the object received by the RGB sensor serving as the image sensor 32 and an incident beam 52 from the object, and may receive the incident beam 52 incident from the object through the image plane 210. In this case, at least one type of pixel, an R pixel capable of receiving light in the red wavelength band, a G pixel capable of receiving light in the green wavelength band, or a B pixel capable of receiving light in the blue wavelength band, may be a light receiving element capable of receiving light for forming an image of at least a portion of the object and the incident beam 52 from the object. For example, if the R pixel is a light receiving element capable of receiving light for forming an image of at least a portion of the object and the incident beam 52 from the object, the G pixel and the B pixel may not be able to receive the incident beam 52 from the object, but may be able to receive light for forming an image of at least a portion of the object. In this case, the incident beam 52 is a light beam in a wavelength band that is at least part of the red wavelength band.

[0202] The control device 50 may distinguish between the imaging result of at least a portion of the image of the object formed on the image plane 210 and the reception result of the incident beam 52 from the object, using a protocol and an algorithm for distinguishing between light for forming an image of at least a portion of the object and the incident beam 52 from the object, based on the light reception result of the imaging device 30D (image sensor 32). The image sensor 32 does not have to be an RGB sensor. Each of the multiple pixels arranged in the image sensor 32 may be a light receiving element capable of receiving light in a wavelength band from visible light to terahertz waves, or may be a light receiving element capable of receiving light in a wavelength band from visible light to millimeter waves, or may be a light receiving element capable of receiving light in a wavelength band from visible light to infrared light.

[0203] Furthermore, some of the pixels arranged on the imaging surface of the image sensor 32 may be light-receiving elements (image-capturing pixels) capable of receiving light for forming an image of at least a portion of an object, and the other pixels may be light-receiving elements (light-receiving pixels) capable of receiving an incident beam 52 from the object. In this case, the pixels (light-receiving pixels) capable of receiving the incident beam 52 from the object receive the incident beam 51 incident via the image surface 210. In this case, the image sensor 30D can be considered a light-receiving unit because it receives the incident beam 52. The pixels (light-receiving pixels) capable of receiving the incident beam 52 from the object on the image sensor 32 of the image sensor 30D may also be referred to as a light-receiving unit. For example, the multiple pixels provided on the image sensor 32 may be arranged in a Bayer array. One pixel (e.g., one G pixel among the R pixel, G pixel, B pixel, and G pixel) of each unit pixel group in this Bayer array may be used as a light-receiving element for receiving the incident beam 52 from the object. In this case, other pixels (e.g., R pixel, G pixel, B pixel, R pixel, B pixel, and another G pixel) among the unit pixel groups in the Bayer array may be used as light receiving elements capable of receiving light for forming an image of at least a portion of the object. Note that the light receiving elements for receiving the incident beam 52 from the object are not limited to elements capable of receiving visible light (e.g., the above-mentioned green wavelength band), but may also be elements capable of receiving light in other wavelength bands (e.g., light in a wavelength band including terahertz waves used in optical wireless communication or light in a wavelength band including infrared light). Note that the imaging element 32 may be a monochrome image sensor.

[0204] The control device 50 of the light irradiation device 1D may control the position change device 40D to perform optical wireless communication with another light irradiation device 1D as an object, based on the result of capturing an image of at least a part of the object by the imaging device 30D (for example, the control device 50 may change the inclination angle of the reflecting element of the incident angle change member 72). In this case, optical wireless communication may be performed by receiving the irradiation beam 51 from the light irradiation device 1D by the light receiving unit 831 of the other light transmitting and receiving device 83, and receiving the incident beam 52 from the other light transmitting and receiving device 83 by the imaging device 30D via the image plane 210 of the imaging optical system 10 of the light irradiation device 1D. For example, the control device 50 of the light irradiation device 1D may control the position changing device 40D so that the irradiation beam 51 from the light irradiation device 1D is incident on the light receiving unit 831 (for example, the inclination angle of the reflective element of the incident angle changing member 72 may be changed) based on the position of a characteristic part of the other party's light transmitting and receiving device 83 (for example, a marker placed on the light transmitting and receiving device 83) on the image acquired by the imaging device 30D, which is identified by the above-mentioned image processing, and the positional relationship between the characteristic part of the other party's light transmitting and receiving device 83 and the light receiving unit 831.

[0205] The control device 50 of the light irradiation device 1D is not limited to the above-described processing and control, and may apply at least a part of the processing and control of the control device 50 of the first embodiment and the control device 50 of the second embodiment. The light irradiation device 1D is not limited to the light transmitting and receiving device 83 as an object, and may perform optical wireless communication with at least one of the light irradiation device 1 of the first embodiment, the light irradiation device 1C of the second embodiment, and the light irradiation device 1D of this embodiment. In this case, the processing and control of the control device 50 of the light irradiation device 1D may apply at least a part of the processing and control of the control device 50 of the light irradiation device 1 of the first embodiment, the control device 50 of the light irradiation device 1C of the second embodiment, and the control device 50 of the above-described embodiment.

[0206] The light irradiation device 1D may perform optical wireless communication with not only the light transmitting and receiving device 83 as an object but also the above-described light receiving device 81 or the above-described light transmitting device 82 as an object. Even in this case, the control device 50 of the light irradiation device 1D may perform optical wireless communication with the light receiving device 81 or the light transmitting device 82 by executing at least a part of the processing and control of the control device 50 of the light irradiation device 1 of the first embodiment, the control device 50 of the light irradiation device 1C of the second embodiment, and the control device 50 of this embodiment. The light irradiation device 1D may be used instead of the light irradiation device 1A of the optical wireless communication system 100A of the first embodiment, and optical wireless communication may be performed between the light irradiation device 1D and zero or more light receiving devices 81, light transmitting devices 82, and light transmitting and receiving devices 83, respectively. Even in the above cases, the control device 50 of the light irradiation device 1D may perform optical wireless communication with zero or more light receiving devices 81, light transmitting devices 82, and light transmitting / receiving devices 83 by executing at least a part of the processing and control of the control device 50 of the light irradiation device 1 of the first embodiment, the control device 50 of the light irradiation device 1C of the second embodiment, and the control device 50 of this embodiment. Note that the light transmitting / receiving device 83 may have the same configuration as the light irradiation device 1, the light irradiation device 1C, or the light irradiation device 1D.

[0207] For example, in the case of optical wireless communication between the light emitting device 1D and a plurality of light receiving devices 81 or a plurality of light transmitting and receiving devices 83, the light emitting device 1D may include a plurality of communication boards 62, a plurality of optical fibers 61, a plurality of light transmitting optical elements 41D, a plurality of collimating lenses 73, and a plurality of incident angle changing members 72, depending on the number of counterpart light receiving devices 81 with which the optical wireless communication is performed. In this case, the light emitting device 1D does not need to include a plurality of communication boards 62, and may generate a plurality of irradiation beams to be incident on each of the plurality of optical fibers 61 from a common communication board 62. Note that the position changing device 40D may include a plurality of incident angle changing members 72. The control device 50 of the light emitting device 1D may individually change the reflection angle of the irradiation beam 51 at each incident angle changing member 72 by controlling the position changing device 40D.

[0208] For example, if the optical wireless communication system 100A includes a light emitting device 1D and two light transmitting and receiving devices 83 (a first light transmitting and receiving device 83-1 and a second light transmitting and receiving device 83-2), the light emitting device 1D may emit a first irradiation beam 51-1 generated by the first communication board 62-1 from the imaging optical system 10 via the first light transmitting optical system 41D-1, the first collimating lens 73-1, the first incident angle changing member 72-1, and the focusing optical system 71, and the first incident beam 52-1 emitted from the first light transmitting and receiving device 83-1 for optical wireless communication with the light emitting device 1D may be received by the imaging device 30D via the imaging optical system 10. Furthermore, the light irradiation device 1D may emit the second irradiation beam 51-2 generated by the second communication board 62-2 from the imaging optical system 10 via the second light transmitting optical system 41D-2, the second collimator lens 73-2, the second incident angle changing member 72-2, and the light collecting optical system 71, and the second incident beam 52-2 emitted from the second light transmitting / receiving device 83-2 for optical wireless communication with the light irradiation device 1D may be received by the imaging device 30D via the imaging optical system 10. Note that the position changing device 40D may include a first incident angle changing member 72-1 and a second incident angle changing member 72-2.

[0209] In this case, the light irradiation system 100A may perform optical wireless communication between the light irradiation device 1D and the first light transmitting and receiving device 83-1 by irradiating the first irradiation beam 51-1 from the light irradiation device 1D to the first light receiving unit 831-1 of the first light transmitting and receiving device 83-1 and receiving the first incident beam 52-1 from the first light transmitting unit 832-1 of the first light transmitting and receiving device 83-1 with the imaging device 30D of the light irradiation device 1D. Also, the light irradiation system 100A may perform optical wireless communication between the light irradiation device 1D and the second light transmitting and receiving device 83-2 by irradiating the second irradiation beam 51-2 from the light irradiation device 1D to the second light receiving unit 831-2 of the second light transmitting and receiving device 83-2 and receiving the second incident beam 52-2 from the second light transmitting unit 832-2 of the second light transmitting and receiving device 83-2 with the imaging device 30D of the light irradiation device 1D. That is, in this example, the light irradiation device 1D may transmit and receive information to and from the first light transmitting and receiving device 83-1. The light irradiation device 1D may transmit and receive information to and from the second light transmitting and receiving device 83-2. The light irradiation device 1D may transmit and receive information to and from the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 simultaneously.

[0210] The control device 50 of the light irradiation device 1D may control the position changing device 40D so that the first irradiation beam 51-1 emitted from the light irradiation device 1D is incident on the first light receiving unit 831-1 (i.e., may change the reflection angle of the first irradiation beam 51-1 at the first incident angle changing member 72-1) based on the position of the characteristic location of the first light transmitting and receiving device 83-1 as an object on the image acquired by the imaging device 30D, which is identified by the image processing described above, and the positional relationship between the characteristic location of the first light transmitting and receiving device 83-1 and the first light receiving unit 831-1 of the first light transmitting and receiving device 83-1. The light irradiation device 1D may receive the first incident beam 52-1 from the first light transmitting unit 832-1 of the first light transmitting and receiving device 83-1 at the imaging device 30D via the imaging optical system 10.

[0211] Furthermore, the control device 50 of the light irradiation device 1D may control the position change device 40D so that the second irradiation beam 51-2 emitted from the light irradiation device 1D is incident on the second light receiving unit 831-2 based on the position of the characteristic location of the second light transmitting and receiving device 83-2 as an object on the image acquired by the imaging device 30D identified by the image processing described above and the positional relationship between the characteristic location of the second light transmitting and receiving device 83-2 and the second light receiving unit 831-2 of the second light transmitting and receiving device 83-2 (i.e., the reflection angle of the second irradiation beam 51-2 at the second incident angle change member 72-2 may be changed). The light irradiation device 1D may receive the second incident beam 52-2 from the second light transmitting unit 832-2 of the second light transmitting and receiving device 83-2 at the imaging device 30D via the imaging optical system 10.

[0212] When optical wireless communication is performed between the light irradiation device 1D and a plurality of light receiving devices 81 or a plurality of light transmitting and receiving devices 83, the light irradiation device 1D does not need to include a plurality of communication boards 62, a plurality of optical fibers 61, a plurality of light transmitting optical elements 41D, a plurality of collimating lenses 73, and a plurality of incident angle changing members 72. For example, the light irradiation device 1D may include a single communication board 81, a single optical fiber 61, a single light transmitting optical element 41D, a single collimating lens 73, and a single incident angle changing member 72. In this case, the single incident angle changing member 72 may be a spatial light modulator or a DMD as a spatial light modulator. When the optical wireless communication system 100A includes a light irradiation device 1D and two light transmitting and receiving devices 83 (a first light transmitting and receiving device 83-1 and a second light transmitting and receiving device 83-2), some of the multiple reflecting elements of the single incident angle changing member 72 (which may be referred to as a first reflecting element group) may be used to change the reflection angle (i.e., change the position of the first illumination beam 51-1 on the conjugate plane 220) so that the first illumination beam 51-1, which is part of the illumination beam 51 from the collimating lens 73, is incident on the first light receiving unit 831-1 of the first light transmitting and receiving device 83-1. In addition, the other reflecting elements (which may be referred to as a second reflecting element group) among the multiple reflecting elements of the single incident angle changing member 72 may be used to change the reflection angle (i.e., change the position of the second irradiation beam 51-2 on the conjugate plane 220) so that the second irradiation beam 51-2, which is the other part of the irradiation beam 51 from the collimator lens 73, is incident on the second light receiving section 831-2 of the second light transmitting / receiving device 83-2.

[0213] In this case, the control device 50 of the light irradiation device 1D may control the position changing device 40D so that the first irradiation beam 51-1 emitted from the light irradiation device 1D is incident on the first light receiving unit 831-1 (i.e., may change the reflection angle of the first irradiation beam 51-1 at the first reflecting element group of the incident angle changing member 72) based on the position of the characteristic location of the first light transmitting and receiving device 83-1 on the image acquired by the imaging device 30D, which is identified by the image processing described above, and the positional relationship between the characteristic location of the first light transmitting and receiving device 83-1 and the first light receiving unit 831-1 of the first light transmitting and receiving device 83-1. The light irradiation device 1D may receive the first incident beam 52-1 from the first light transmitting unit 832-1 of the first light transmitting and receiving device 83-1 at the imaging device 30D via the imaging optical system 10.

[0214] Furthermore, the control device 50 of the light irradiation device 1D may control the position change device 40D so that the second irradiation beam 51-2 emitted from the light irradiation device 1D is incident on the second light receiving unit 831-2 based on the position of the characteristic location of the second light transmitting and receiving device 83-2 as an object on the image acquired by the imaging device 30D identified by the image processing described above and the positional relationship between the characteristic location of the second light transmitting and receiving device 83-2 and the second light receiving unit 831-2 of the second light transmitting and receiving device 83-2 (i.e., may change the reflection angle of the second irradiation beam 51-2 at the second reflecting element group of the incident angle change member 72). The light irradiation device 1D may receive the second incident beam 52-2 from the second light transmitting unit 832-2 of the second light transmitting and receiving device 83-2 at the imaging device 30D via the imaging optical system 10. Furthermore, the control device 50 of the light irradiation device 1D may identify the positions of the characteristic locations of the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 on the same image acquired by the imaging device 30D using the image processing described above.

[0215] The image sensor 32 of the image sensor 30D may be configured to be able to distinguish between and receive the first incident beam 52-1 and the second incident beam 52-2. For example, the first incident beam 52-1 and the second incident beam 52-2 may have different light conditions. The light conditions include at least one of wavelength, frequency, phase, and degree of polarization. The image sensor 32 may have light receiving elements (light receiving pixels) arranged so as to be able to distinguish between the differences in the light conditions of the first incident beam 52-1 and the second incident beam 52-2. For example, when the wavelengths of the first incident beam 52-1 and the second incident beam 52-2 are different, light receiving elements capable of receiving light having the wavelength of the first incident beam 52-1 (e.g., light in a wavelength band including terahertz waves) and light receiving elements capable of receiving light having the wavelength of the second incident beam 52-2 (light in a wavelength band including infrared light) may be arranged on the imaging surface as light receiving pixels. The light receiving element capable of receiving light of the wavelength of the first incident beam 52-1 may not be able to receive light of the wavelength of the second incident beam 52-2. The light receiving element capable of receiving light of the wavelength of the second incident beam 52-2 may not be able to receive light of the wavelength of the first incident beam 52-1. The control device 50 of the light irradiation device 1D may distinguish between the first incident beam 52-1 and the second incident beam 52-2 based on the light receiving result of the imaging device 30D (imaging element 32) described above.

[0216] The control device 50 of the light irradiation device 1D may distinguish between the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 and perform optical wireless communication. For example, the control device 50 may distinguish between the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 based on an image acquired by the imaging device 30D. In this case, characteristic locations may be provided on the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 so that the characteristic locations of the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 can be distinguished from each other on the image acquired by the imaging device 30D. For example, the shape of a marker as the characteristic location of the first light transmitting and receiving device 83-1 may be different from the shape of a marker as the characteristic location of the second light transmitting and receiving device 83-2. In this case, the control device 50 may distinguish between the first light transmitting / receiving device 83-1 and the second light transmitting / receiving device 83-2 based on the shape of the marker of the first light transmitting / receiving device 83-1 and the shape of the marker of the second light transmitting / receiving device 83-2 on the image acquired by the imaging device 30D.

[0217] In addition, the control device 50 may distinguish between the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 based on the results of reception of the first incident beam 52-1 from the first light transmitting and receiving device 83-1 and the second incident beam 52-2 from the second light transmitting and receiving device 83-2 by the imaging device 30D. In this case, incident beams that allow the first incident beam 52-1 from the first light transmitting and receiving device 83-1 and the second incident beam 52-2 from the second light transmitting and receiving device 83-2 to be distinguished may be emitted from each of the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2. For example, as described above, the first incident beam 52-1 and the second incident beam 52-2 may be under different light conditions. The control device 50 may distinguish between the first light transmitting and receiving device 83-1 and the second light transmitting and receiving device 83-2 based on the difference in light conditions (e.g., difference in wavelength, as described above) between the first incident beam 52-1 from the first light transmitting and receiving device 83-1 and the second incident beam 52-2 from the second light transmitting and receiving device 83-2 received by the imaging device 30D.

[0218] Note that calibration of the imaging device 30D may be performed in the same manner as in the first embodiment. Furthermore, calibration of the incident angle changing member 72 may be performed. In the calibration of the incident angle changing member 72, the reflection angle of the irradiation beam 51 at the incident angle changing member 72 (the inclination angle of the reflecting element of the incident angle changing member 72) may be associated with a position on the image acquired by the imaging device 30D. The association of the reflection angle of the irradiation beam 51 at the incident angle changing member 72 with a position on the image acquired by the imaging device 30D may be performed, for example, using the above-mentioned reflecting surface.

[0219] For example, the light irradiation device 1D may irradiate light from the light-sending optical element 41D toward the reflective surface via the incident angle changing member 72, the light-collecting optical system 71, the optical member 20, and the imaging optical system 10, and the imaging device 30D may receive light that is irradiated toward the reflective surface from the imaging optical system 10 and reflected by the reflective surface, thereby associating the reflection angle of the irradiation beam 51 at the incident angle changing member 72 with a position on an image acquired by the imaging device 30D. As described above, when the reflection angle of the irradiation beam 51 at the incident angle changing member 72 (the inclination angle of the reflecting element of the incident angle changing member 72) changes, the irradiation position (irradiation orientation) of the light emitted from the imaging optical system 10 changes. Therefore, when the reflection angle of the irradiation beam 51 at the incident angle changing member 72 changes, the reflection position on the reflective surface also changes, and therefore the incidence position of the reflected light on the imaging device 30D (the imaging surface of the imaging element 32) also changes (i.e., the position of the reflected light on the image acquired by the imaging device 30D also changes). It can also be said that the light irradiation device 1D calibrates the incident angle changing member 72 based on the reflection angle of the irradiation beam 51 at the incident angle changing member 72 and the position of the reflected light on the image acquired by the imaging device 30D. Note that the calibration of the incident angle changing member 72 may also be referred to as calibration of the incident angle changing member 72 and the imaging device 30D, calibration of the position changing device 40D, or calibration of the position changing device 40D and the imaging device 30D.

[0220] The light irradiation device 1D may include an optical system on the optical path between the focusing optical system 71 and the incident angle changing member 72. This optical system may be an optical system that makes the pupil of the focusing optical system 71 and the incident angle changing member 72 conjugate with each other. For example, if the incident angle changing member 72 is a reflective spatial light modulator such as a DMD or a galvanometer mirror, this optical system may be an optical system that makes the pupil of the focusing optical system 71 and the reflective surface of the reflective spatial light modulator such as a DMD or the galvanometer mirror conjugate with each other. This optical system may include at least one existing optical member.

[0221] As described above, according to this embodiment, the light-concentrating optical system 71 is provided to concentrate the irradiation beam 51 emitted from the light-emitting unit of the light generating device 60, and the incident angle changing member 72 is provided to change the angle of incidence of the irradiation beam 51 on the light-concentrating optical system 71. By changing the angle of incidence of the irradiation beam 51 on the light-concentrating optical system 71, the position of the irradiation beam 51 on the conjugate plane 220 is changed (i.e., the irradiation position of the irradiation beam 51 emitted from the imaging optical system 10 is changed). Therefore, according to this embodiment, it is not necessary to move the light-transmitting and receiving optical element 41 on the x-z plane (for example, on a plane intersecting with the optical axis 111a or 111c on the conjugate plane 220 side of the imaging optical system 10). Therefore, according to this embodiment, it is possible to reduce the size of the device. Furthermore, according to this embodiment, since it is not necessary to move the light-transmitting and receiving optical element 41 on the x-z plane, it is possible to change the irradiation position of the irradiation beam 51 at high speed.

[0222] Furthermore, according to the above-described embodiment, the imaging device 30D has a plurality of imaging pixels for capturing at least a portion of an image of an object, and at least some of the plurality of imaging pixels are capable of receiving the incident beam 52. Furthermore, the imaging pixels capable of receiving the incident beam 52 receive the incident beam 52 incident via the image plane 210. Therefore, according to this embodiment, it is not necessary to move the light-transmitting and receiving optical element 41 on the x-z plane (e.g., on a plane intersecting the optical axis 111a or 111c on the conjugate plane 220 side of the imaging optical system 10) to receive the incident beam 52. Therefore, according to this embodiment, it is possible to reduce the size of the device. Furthermore, according to this embodiment, it is not necessary to move the light-transmitting and receiving optical element 41 on the x-z plane, so the incident beam 52 can be received at high speed.

[0223] Furthermore, according to the above-described embodiment, the imaging device 30D has a plurality of imaging pixels for capturing at least a portion of an image of an object, and light-receiving pixels, which are different from the imaging pixels and serve as light-receiving units for receiving the incident beam 52. Furthermore, the light-receiving pixels receive the incident beam 52 incident via the image plane 210. Therefore, according to this embodiment, it is not necessary to move the light-transmitting and receiving optical element 41 on the x-z plane to receive the incident beam 52. Therefore, according to this embodiment, it is possible to miniaturize the device. Furthermore, according to this embodiment, it is not necessary to move the light-transmitting and receiving optical element 41 on the x-z plane, so the incident beam 52 can be received at high speed.

[0224] [Fourth Embodiment] Next, a light irradiation device 1E according to a fourth embodiment will be described with reference to FIGS. 10 to 12. FIG. 10 is a schematic diagram illustrating the configuration of a light irradiation device according to the fourth embodiment. First, the schematic configuration of the light irradiation device 1E according to the fourth embodiment will be described with reference to the same figure. The light irradiation device 1E differs from the light irradiation device 1D in that it includes a light transmitting and receiving optical element 41E instead of the light transmitting optical element 41D. Furthermore, the light irradiation device 1E includes an imaging device 30E instead of the imaging device 30D. The light irradiation device 1E may be provided with the above-described characteristic features. The light irradiation device 1E may be installed on the above-described movable body. In the description of the light irradiation device 1E, components similar to those of the light irradiation device 1D are denoted by the same reference numerals, and their description may be omitted. The control device 50 is not shown in FIG. 10.

[0225] In this embodiment, the light irradiation device 1E may perform optical wireless communication.

[0226] The light transmitting and receiving optical element 41E includes at least a light transmitting optical system 412 and a light receiving optical system 413. The light transmitting and receiving optical element 41E may also be referred to as a light emitting unit, a light receiving unit, or a light transmitting and receiving unit. The light transmitting optical system 412 may include an optical fiber that emits the irradiation beam 51 generated by the communication board 62 toward the collimating lens 73. The light transmitting optical system 412 may also include an existing optical component other than an optical fiber. The light transmitting optical system 412 may be composed of at least one existing optical component as long as it can emit the irradiation beam 51 from the communication board 62 toward the collimating lens 73. The light transmitting optical system 412 may be similar to the light transmitting optical element 41D described above. The light transmitting optical system 412 may also be referred to as a light transmitting optical element or a light emitting unit. The light transmitting optical system 412 may include, for example, the optical fiber 61-1 and Fresnel lens 42-1 described above.

[0227] The light-receiving optical system 413 may include an optical fiber that emits the incident beam 52, which has been incident via the imaging optical system 10, the focusing optical system 71, the incident angle changing member 72, and the collimating lens 73, toward the communication board 62. The light-receiving optical system 413 may include an existing optical member other than the optical fiber. The light-receiving optical system 413 may be composed of at least one existing optical member as long as it can emit the incident beam 52 from the collimating lens 73 toward the communication board 62. The light-receiving optical system 413 may also be referred to as a light-receiving optical element or a light-receiving unit. The light-receiving optical system 413 may include, for example, the above-mentioned optical fiber 61-2 and Fresnel lens 42-2.

[0228] Similar to the imaging device 30 described above, the imaging device 30E is disposed near the image plane 210 of the imaging optical system 10 and captures an image of at least a portion of an object formed on the image plane 210. Similar to the imaging element 31 of the imaging device 30, the imaging device 30E includes an imaging element 33 having a plurality of pixels arranged on the imaging plane. It can also be said that the imaging element 33 captures a reduced image of at least a portion of an object formed on the image plane 210. For example, the imaging surface of the imaging element 33 may be disposed on the image plane 210 of the imaging optical system 10. Furthermore, the imaging surface of the imaging element 33 does not have to be disposed on the image plane 210 of the imaging optical system 10, but may be disposed near the image plane 210. Note that the imaging element 33 may be an imaging element capable of outputting color image data (e.g., an RGB image sensor) or an imaging element capable of outputting monochrome image data (e.g., a monochrome image sensor).

[0229] The position changing device 40E includes at least an incident angle changing member 72. The position changing device 40E changes the position of the irradiation beam 51 from the light sending optical system 412 (collimator lens 73) on the conjugate plane 220. It can also be said that the position changing device 40E changes the position of the incident beam 52 from the optical member 20 that is incident on the light receiving optical system 413 on the conjugate plane 220. The position changing device 40E may include at least one existing optical member in addition to the incident angle changing member 72. The position changing device 40E may be another existing device that can change the position of the irradiation beam 51 incident on the conjugate plane 220 from the light sending optical system 412 via the collimator lens 73. The position changing device 40E may be the same as the position changing device 40D.

[0230] The incident angle changing member 72 may be, for example, a spatial light modulator such as a mirror array having a plurality of two-dimensionally arranged reflective elements, each of which has a variable tilt angle. In this case, the incident angle changing member 72 may be a DMD (Digital Mirror Device) as a spatial light modulator. The incident angle changing member 72 is not limited to a reflective type, and may be an existing transmissive type spatial light modulator. Note that the incident angle changing member 72 is not limited to a spatial light modulator, and may be a galvanometer mirror (which may also be called a galvanometer scanner) or a polygon mirror (which may also be called a polygon scanner).

[0231] The illumination beam 51 from the light-sending optical system 413 is converted into parallel light by the collimator lens 73 and enters the incident angle changing member 72. The illumination beam 51 that has entered the incident angle changing member 72 is emitted toward an object (e.g., the opposing light-transmitting / receiving device 83) via the focusing optical system 71, the optical member 20, and the imaging optical system 10. The incident angle changing member 72 may reflect the illumination beam 51 from the light-sending optical system 412 at any angle, causing the illumination beam 51 to be incident on the focusing optical system 71 at any incident angle. The incident angle changing member 72 can change the reflection angle of the incident illumination beam 51 (e.g., the inclination angle of the reflecting element of the incident angle changing member 72).

[0232] The angle of incidence of the illumination beam 51 onto the focusing optical system 71 is changed by changing the reflection angle of the illumination beam 51 with the incident angle changing member 72. The focusing optical system 71 focuses the incident illumination beam 51 toward the conjugate plane 220. Here, for example, if the focusing optical system 71 is an fθ lens, the focusing position on the conjugate plane 220 changes depending on the angle of incidence of the incident illumination beam 51. Therefore, the control device 50 changes the position of the illumination beam 51 on the conjugate plane 220 by changing the angle of incidence of the illumination beam 51 onto the focusing optical system 71. Note that the setting of the illumination position on the object of the illumination beam 51 from the light transmitting optical system 412 by the control device 50 (i.e., control of the position changing device 40E) is similar to the setting of the illumination position on the object of the illumination beam 52 from the light transmitting and receiving optical element 41D by the control device 50 in the third embodiment described above (i.e., control of the position changing device 40D) and therefore will not be described again.

[0233] An incident beam 52 incident on the imaging optical system 10 from an object (for example, the other party's light transmitting / receiving device 83) is incident on the incident angle changing member 72 via the optical member 20 and the focusing optical system 71. The incident angle changing member 72 reflects the incident beam 52 toward the collimating lens 73. The collimating lens 73 focuses the incident beam 52 from the incident angle changing member 72 onto the light receiving optical system 412. The light focused on the light receiving optical system 412 is received by the communication board 62. By changing the reflection angle of the incident beam 52 with the incident angle changing member 72, the incident beam 52 that has passed through any position on the conjugate plane 220 can be selectively emitted toward the light receiving optical system 413 (communication board 62). Furthermore, by changing the reflection angle of the incident beam 52 with the incident angle changing member 72, it can also be said that the optical path of the incident beam 52 that enters the light receiving optical system 413 (communication board 62) from the conjugate surface 220 (optical member 20) via the incident angle changing member 72 can be selected.

[0234] The incident angle changing member 72 may pass through any position on the conjugate plane 220 and reflect the incident beam 52, which has entered via the focusing optical system 71, at any angle, so that the incident beam 52 is emitted toward the light-receiving optical system 413 (communication board 62). When the focusing position of the incident beam 52 on the conjugate plane 220 changes, the incident position of the incident beam 52 on the focusing optical system 71 changes. Here, if the focusing optical system 71 is an fθ lens, when the incident position of the incident beam 52 on the focusing optical system 71 changes, the exit angle of the incident beam 52 from the focusing optical system 71 changes. When the exit angle of the incident beam 52 from the focusing optical system 71 changes, the incident angle of the incident beam 52 on the incident angle changing member 72 changes. The control device 50 controls the position changing device 40E (incident angle changing member 72) so that the incident beam 52 enters the light receiving optical system 413 (communication board 62) via the collimator lens 73 according to the incident angle of the incident beam 52 to the incident angle changing member 72, i.e., sets the reflection angle of the incident beam 52 (for example, the inclination angle of the reflective element of the incident angle changing member 72).

[0235] Note that, depending on the positional relationship between the light emitting device 1E and an object (e.g., the counterpart light transmitting / receiving device 83), when the incident position of the incident beam 52 from the object onto the imaging optical system 10 (e.g., the optical element closest to the object in the imaging optical system 10), i.e., the light receiving position of the incident beam 52, changes, the focusing position of the incident beam 52 at the conjugate plane 220 changes. Therefore, the position changing device 40E (incident angle changing member 72) can make the incident beam 52 incident at any position on the imaging optical system 10 incident on the light receiving optical system 413 (communication board 62) by changing the reflection angle of the incident beam 52 (e.g., the inclination angle of the reflecting element of the incident angle changing member 72). Note that, it can also be said that the position changing device 40E changes the light receiving position of the incident beam 52 incident on the light receiving optical system 413 (communication board 62) by changing the reflection angle of the incident beam 52 (e.g., the inclination angle of the reflecting element of the incident angle changing member 72). As described above, at least one of the focusing optical system 71 and the collimating lens 73 contributes to changing the position of the irradiation beam 51 on the conjugate plane 220, and therefore can also be considered part of the position changing device 40E.

[0236] For example, the incident angle changing member 72 may be a DMD (Digital Mirror Device) having a plurality of reflecting elements arranged two-dimensionally, and capable of individually changing the tilt angle of each reflecting element. Here, the incident angle changing member 72 can be said to have a light reflection region capable of reflecting incident light by the plurality of reflecting elements arranged two-dimensionally. Fig. 11 is a schematic diagram illustrating a case where the light reflection region of the incident angle changing member 72 according to the fourth embodiment is divided into a light sending region 4141 that reflects at least a portion of the irradiation beam 51 from the light sending optical system 412 toward the light collecting optical system 71 and a light receiving region 4142 that reflects at least a portion of the incident beam 52 from the light collecting optical system 71 toward the light receiving optical system 413.

[0237] The division of light reception and light transmission will be described with reference to the same figure. The multiple reflective elements of the incident angle changing member 72 corresponding to the light transmission region 4141 may be used to change the reflection angle (i.e., change the position of the irradiation beam 51 on the conjugate plane 220) so that the irradiation beam 51 from the light transmission optical system 412 is incident on an object (for example, the counterpart light irradiation device 1E), and the other multiple reflective elements of the incident angle changing member 72 corresponding to the light receiving region 4142 may be used to change the reflection angle so that the incident beam 52 from the light collection optical system 71 is incident on the light receiving optical system 413 (communication board 62).

[0238] As an example, when the light irradiating device 1E and the above-described light transmitting and receiving device 83 communicate optically wirelessly, the control device 50, for example, by the above-described image processing, identifies the position of a characteristic location provided on the light transmitting and receiving device 83 (for example, a marker placed on the light transmitting and receiving device 83) on the image acquired by the imaging device 30E. Based on the position of the identified characteristic location on the image and the positional relationship between the characteristic location and the light receiving unit 831 of the light transmitting and receiving device 83, which is the target to which the irradiation beam 51 is irradiated, the control device 50 may control the position changing device 40E (i.e., set the inclination angles of the multiple reflecting elements of the incident angle changing member 72 corresponding to the light transmitting region 4141). The control device 50 may control the position changer 40E (i.e., set the inclination angles of the other multiple reflecting elements of the incident angle changer 72 corresponding to the light-receiving area 4142) so that the incident beam 52 emitted from the light-transmitting unit 832 is incident on the light-receiving optical system 413 (communication board 62) based on the position on the image of the characteristic location identified as described above and the positional relationship between the characteristic location and the light-transmitting unit 832 of the light-transmitting / receiving device 83 from which the incident beam 52 is emitted. Note that the characteristic location of the light-transmitting / receiving device 83 used when controlling the position changer 40E so that the irradiation beam 51 emitted from the irradiation device 1E is incident on the light-receiving unit 831 may be different from the characteristic location used when controlling the position changer 40E so that the incident beam 52 emitted from the light-transmitting unit 832 is incident on the light-receiving optical system 413. For example, the respective characteristic locations may be different characteristic locations (e.g., marks of different shapes or colors) arranged on the light-transmitting / receiving device 83.

[0239] In the above case, the light receiving unit 831 and the light transmitting unit 832 of the light transmitting and receiving device 83 are not limited to being arranged adjacent to or close to each other, but even if they are arranged apart, the incident beam 52 from the light transmitting unit 832 can be received by the light receiving optical system 413 (communication board 62) while the irradiation beam 51 is incident on the light receiving unit 831. Note that optical wireless communication is also possible with the above-mentioned light receiving device 81 and light transmitting device 82, not limited to the light transmitting and receiving device 83. In other words, the incident beam 52 from the light transmitting unit 821 of the light transmitting device 82 can be received by the light receiving optical system 413 (communication board 62) while the irradiation beam 51 is incident on the light receiving unit 811 of the light receiving device 81.

[0240] 12 , the light transmitting and receiving optical element 41E may be disposed at a defocus position 732. For example, an end of the light transmitting and receiving optical element 41E may be disposed at the defocus position 732. For example, the light emitting end of the optical fiber of the light transmitting optical system 412 of the light transmitting and receiving optical element 41E (the emitting end of the optical fiber that emits the irradiation beam 51 to the collimator lens 73) and the light receiving end of the optical fiber of the light receiving optical system 413 of the light transmitting and receiving optical element 41E (the light receiving end of the optical fiber that receives the incident beam 52 from the collimator lens 73) may be disposed at the defocus position 732. The light transmitting and receiving optical element 41E may be disposed at the defocus position 732, which is located further in the positive direction of the x-axis than the focus position 731 on the light transmitting and receiving optical element 41E side than the collimator lens 73. The light transmitting and receiving optical element 41E may be disposed at the defocus position, which is located further in the negative direction of the x-axis than the focus position 731. The focus position 731 may also be referred to as the focal position of the collimator lens 73. The focus position 731 may also be referred to as the focal position of the light-collecting optical system 71.

[0241] Depending on the light distribution of the irradiation beam 51 emitted from the light-transmitting optical system 412 and the light distribution of the incident beam 52 incident on the light-receiving optical system 413, a portion of the optical path of the irradiation beam 51 may overlap a portion of the optical path of the incident beam 52 in the light irradiation device 1E. In this case, the reflection angles of the irradiation beam 51 and the incident beam 52 cannot be differentiated and changed by the multiple reflecting elements corresponding to the light-transmitting region 4141 and the multiple reflecting elements corresponding to the light-receiving region 4142. Therefore, an optical element that adjusts the light distribution of the irradiation beam 51 from the light-transmitting optical system 412 may be provided on the optical path between the light-transmitting optical system 412 and the collimating lens 73 so that a portion of the optical path of the irradiation beam 51 does not overlap a portion of the optical path of the incident beam 52. This optical element may be a prism. For example, a prism (e.g., a triangular prism) having an apex angle in the positive y-axis direction may be provided on the optical path between the light-transmitting optical system 412 and the collimating lens 73. An optical element that adjusts the light distribution of the incident beam 52 incident on the light-receiving optical system 413 may be provided on the optical path between the light-receiving optical system 413 and the collimating lens 73 so that part of the optical path of the illumination beam 51 does not overlap part of the optical path of the incident beam 52. This optical element may be a prism. For example, a prism (e.g., a triangular prism) having an apex angle in the negative direction of the y-axis may be provided on the optical path between the light-receiving optical system 413 and the collimating lens 73.

[0242] The incident angle changing member 72 is not limited to a spatial light modulation element, and may be a galvanometer mirror or a polygon mirror. The light irradiation device 1E may include an optical system on the optical path between the focusing optical system 71 and the incident angle changing member 72. This optical system may be an optical system that makes the pupil of the focusing optical system 71 and the incident angle changing member 72 conjugate with each other. For example, if the incident angle changing member 72 is a reflective spatial light modulator such as a DMD or a galvanometer mirror, this optical system may be an optical system that makes the pupil of the focusing optical system 71 and the reflective surface of the reflective spatial light modulator such as a DMD or the galvanometer mirror conjugate with each other. This optical system may include at least one existing optical member.

[0243] As described above, according to this embodiment, the incident angle changing member 72 is provided to change the incident angle of the illumination beam 51 on the focusing optical system 71, and by changing the incident angle of the illumination beam 51 on the focusing optical system 71, the position of the illumination beam 51 on the conjugate plane 220 is changed (that is, the irradiation position of the illumination beam 51 emitted from the imaging optical system 10 is changed). Therefore, according to this embodiment, it is not necessary to move the light transmitting and receiving optical element 41 on the x-z plane (for example, on a plane intersecting with the optical axis 111a or 111c on the conjugate plane 220 side of the imaging optical system 10). Therefore, according to this embodiment, it is possible to reduce the size of the device. Furthermore, according to this embodiment, since it is not necessary to move the light transmitting and receiving optical element 41 on the x-z plane, it is possible to change the irradiation position of the illumination beam 51 at high speed.

[0244] As described above, according to this embodiment, the incident angle changing member 72 is provided, thereby changing the reflection angle of the incident beam 52 incident at a predetermined angle from the focusing optical system 71, and causing the incident beam 52 to be incident on the light-receiving optical system 413 (communication board 62). Therefore, according to this embodiment, it is not necessary to move the light-transmitting and receiving optical element 41 on the x-z plane (for example, on the plane intersecting with the optical axis 111a or 111c on the conjugate plane 220 side of the imaging optical system 10). Therefore, according to this embodiment, it is possible to reduce the size of the device. Furthermore, according to this embodiment, since it is not necessary to move the light-transmitting and receiving optical element 41 on the x-z plane, it is possible to change the light-receiving position of the incident beam 52 at high speed.

[0245] In this embodiment, at least one of the irradiation beam 51 and the incident beam 52 is not limited to light for optical wireless communication. For example, at least one of the irradiation beam 51 and the incident beam 52 may be light for optical wireless power transmission. The wavelength of the light for optical wireless power transmission may be in the infrared wavelength band, the ultraviolet wavelength band, or the visible light wavelength band. The output of the light for optical wireless power transmission may be several watts, several tens of watts, or several kilowatts. As an example, when the irradiation beam 51 is light for optical wireless power transmission, the light irradiation device 1D may supply power to a target device for optical wireless power transmission (e.g., at least one of the light irradiation device 1D, the light receiving device 82, and the light transmitting and receiving device 83) by irradiating the target device with the light through processing and control by the control device 50. In addition, the light irradiation device 1D may also be referred to as a power supply device.

[0246] Fifth Embodiment FIG. 13 is a schematic diagram illustrating a light irradiation device according to a fifth embodiment. A light irradiation device 1F according to the fifth embodiment will be described with reference to FIG. 13. The light irradiation device 1F differs from the light irradiation device 1D of the third embodiment in that it includes a light-sending optical element 41F instead of the light-sending optical element 41D of the light irradiation device 1D. The light irradiation device 1F also differs from the light irradiation device 1D in that it includes a collimator lens 73F. The light irradiation device 1F may be provided with the above-described characteristic features. The light irradiation device 1F may be mounted on the above-described movable body. In the description of the light irradiation device 1F, components similar to those of the light irradiation device 1D are denoted by the same reference numerals, and their description may be omitted. The control device 50 is not shown in FIG. 13.

[0247] In this embodiment, the light irradiation device 1F may perform optical wireless communication. For example, the light irradiation device 1F may perform optical wireless communication with a plurality of light receiving devices 81, a plurality of light transmitting devices 82, or a plurality of light transmitting and receiving devices 83 as objects. The light irradiation device 1F may perform optical wireless communication with at least two of the three types of devices, the light transmitting and receiving device 83, the light transmitting device 82, and the light transmitting and receiving device 83. The light irradiation device 1F may perform optical wireless communication with a plurality of light irradiation devices 1, a plurality of light irradiation devices 1C, a plurality of light irradiation devices 1D, or a plurality of light irradiation devices 1E as objects. The light irradiation device 1F may perform optical wireless communication with at least two of the four types of devices, the light irradiation device 1, the light irradiation device 1C, the light irradiation device 1D, and the light irradiation device 1E as objects. The light irradiation device 1F may be used instead of the light irradiation device 1A of the optical wireless communication system 100A of the first embodiment to perform optical wireless communication with a plurality of devices included in the optical wireless communication system 100A.

[0248] The light-sending optical element 41F may include a plurality of optical fibers that transmit the respective illumination beams 51, which are obtained by dividing the illumination beam 51 generated by the communication board 62 using a distributor (not shown), toward the corresponding collimating lenses 73F. For example, as shown in FIG. 13 , the light-sending optical element 41F may include three light-sending optical elements (a first light-sending optical element 415-1, a second light-sending optical element 415-2, and a third light-sending element 415-3). The light-sending optical element 41F may also include existing optical components in addition to the plurality of optical fibers. The light-sending optical element 41F may be composed of at least one existing optical component as long as it can emit each of the plurality of illumination beams 51 divided from the communication board 62 toward the corresponding collimating lenses 73F. The light-sending optical element 41F may also include, for example, a plurality of the above-described optical fibers 61-1 and a plurality of the above-described Fresnel lenses 42-1. Note that one optical fiber (and / or optical member) of the light-sending optical element 41F can also be considered to be the light-sending optical element 41D of the third embodiment. In other words, the light-sending optical element 41F can also be considered to include multiple light-sending optical elements 41D. Note that the number of communication boards 62 included in the light irradiation device 1F is not limited to one, and multiple boards 62 may be included. In this case, the light irradiation device 1F may include communication boards 62 corresponding to each of the multiple optical fibers of the light-sending optical element 41F. In other words, the light irradiation device 1F may include multiple communication boards 62, the number of which is the same as the number of optical fibers of the light-sending optical element 41F. In this case, the communication beams 51 generated by the respective communication boards 62 may be emitted toward the collimating lens 73F via the respective optical fibers of the light-sending optical element 41F.

[0249] The collimating lens 73F converts each of the illumination beams 51 emitted from the light-sending optical element 41F into parallel light. For example, the collimating lens 73F includes a plurality of collimating lenses that convert each of the illumination beams 51 emitted from the light-sending optical element 41F into parallel light. For example, as shown in FIG. 13 , the collimating lens 73F may include three collimating lenses (a first collimating lens 73-1, a second collimating lens 73-2, and a third collimating lens 73-3). Note that the collimating lens 73F may include existing optical components in addition to the plurality of collimating lenses. Note that one collimating lens of the collimating lens 73F can also be considered as the collimating lens 73 of the third embodiment. In other words, the collimating lens 73F can also be considered to include a plurality of collimating lenses 73.

[0250] 13, the collimator lens 73-1 may collimate the light emitted from the first light-transmitting optical element 415-1, the collimator lens 73-2 may collimate the light emitted from the second light-transmitting optical element 415-2, and the collimator lens 73-3 may collimate the light emitted from the third light-transmitting optical element 415-3. The communication board 62 may also be referred to as the light-transmitting light source. The communication board 62 and the light-transmitting optical element 41F may also be considered as a whole to be the light-transmitting light source. The communication board 62, the light-transmitting optical element 41F, and the collimator lens 73F may also be considered as a whole to be the light-transmitting light source.

[0251] The imaging device 30 identifies and independently receives the multiple incident beams 52 incident on the imaging optical system 10. The incident angle changing member 72 may be, for example, a spatial light modulator such as a mirror array having multiple reflective elements arranged two-dimensionally, with the tilt angle of each reflective element being variable. In this case, the incident angle changing member 72 may be a DMD (Digital Mirror Device) as the spatial light modulator. The incident angle changing member 72 is not limited to a reflective type, and may also be an existing transmissive type spatial light modulator. Here, a case will be described in which the light irradiation device 1F performs optical wireless communication with three light transmitting and receiving devices 83 (a first light transmitting and receiving device 83-1, a second light transmitting and receiving device 83-2, and a third light transmitting and receiving device 83-3). In this case, the light irradiation device 1F may include three collimating lenses (first collimating lens 73-1, second collimating lens 73-2, and third collimating lens 73-3) and three light-sending optical elements (first light-sending optical element 415-1, second light-sending optical element 415-2, and third light-sending element 415-3). The light irradiation device 1F may also include three communication boards (first communication board 62-1, second communication board 62-2, and third communication board 62-3) that generate irradiation beams 51 (first irradiation beam 51-1, second irradiation beam 51-2, and third irradiation beam 51-3) that are incident on the three light-sending optical elements, respectively. The incident angle changing member 72 may be a DMD (Digital Mirror Device). Here, at least some of the plurality of reflective elements of the incident angle changing member 72 (which may be referred to as a first reflective element group) may be used to change the reflection angle (i.e., change the position of the illumination beam 51 on the conjugate plane 220) so that the first illumination beam 51-1 from the first collimator lens 73-1 is incident on the first light-receiving unit 831-1 of the first light-transmitting and receiving device 83-1. At least some of the other of the plurality of reflective elements of the incident angle changing member 72 (which may be referred to as a second reflective element group different from the first reflective element group) may be used to change the reflection angle so that the second illumination beam 51-2 from the second collimator lens 73-2 is incident on the second light-receiving unit 831-2 of the second light-transmitting and receiving device 83-2.At least some of the other multiple reflective elements of the incident angle changing member 72 (which may be referred to as a third reflective element group different from the first and second reflective element groups) may be used to change the reflection angle so that the third irradiation beam 51-3 from the third collimator lens 73-3 is incident on the third light receiving unit 831-3 of the third light transmitting and receiving device 83-3.

[0252] The light irradiation device 1F may emit the first irradiation beam 51-1 generated by the first communication board 62-1 from the imaging optical system 10 via the first light-transmitting optical element 415-1, the first collimating lens 73-1, the first reflecting element group of the incident angle changing member 72, and the condensing optical system 71, and the first incident beam 52-1 emitted from the first light-transmitting and receiving device 83-1 may be received by the imaging device 30D via the imaging optical system 10. Furthermore, the light irradiation device 1F may emit the second irradiation beam 51-2 generated by the second communication board 62-2 from the imaging op...

Claims

1. A light irradiation device that irradiates an object with an irradiation beam from a light generating device, An imaging optical system; an optical member that emits light incident via the imaging optical system toward an image plane of the imaging optical system and emits the irradiation beam from the light generating device that is incident via a conjugate plane conjugate with the image plane toward the imaging optical system; an imaging device that captures at least a part of an image of the object formed on the image plane by the imaging optical system; a position changing device that changes a position of the irradiation beam from the light generating device on the conjugate plane to change an irradiation position of the irradiation beam emitted from the imaging optical system; A control device that controls the position change device based on an imaging result of the imaging device; Equipped with The control device controls the position change device based on the imaging result of the imaging device, and the light irradiation device irradiates at least a part of the object with the irradiation beam emitted from the imaging optical system.

2. The imaging optical system is telecentric on the conjugate plane side. The light irradiation device according to claim 1 .

3. The maximum angle of view of the imaging optical system is 170° or more. The light irradiation device according to claim 1 or 2.

4. The imaging optical system forms a reduced image of the object on the image plane. The light irradiation device according to claim 1 .

5. The conjugate surface is a first conjugate surface, and an optical system that forms a second conjugate surface conjugate to the first conjugate surface is further included. the illumination beam is incident on the optical member via the second conjugate surface and the first conjugate surface, The position changing device changes the position of the illumination beam in the second conjugate plane. The light irradiation device according to claim 1 .

6. The optical system between the first conjugate surface and the second conjugate surface is a magnifying optical system. The light irradiation device according to claim 5 .

7. The control device controls the position change device based on a characteristic portion of the object detected based on the imaging result. The light irradiation device according to claim 1 .

8. The imaging device has a plurality of pixels. The light irradiation device according to claim 1 .

9. the light generating device includes a light emitting unit that emits the irradiation beam, The position changing device moves the light emitting unit in a direction intersecting an optical axis of the imaging optical system on the light emitting unit side. The light irradiation device according to claim 1 .

10. a focusing optical system arranged on an optical path between a light emitting unit of the light generating device and the optical member, the focusing optical system focusing the irradiation beam emitted from the light emitting unit; The position change device has an incident angle change member that changes an incident angle of the illumination beam to the focusing optical system, and changes the position of the illumination beam on the conjugate plane by changing the incident angle of the illumination beam to the focusing optical system. The light irradiation device according to any one of claims 1 to 8.

11. the position-changing device comprises a spatial light modulator that spatially modulates the illumination beam from the light-generating device; The light pattern spatially modulated by the spatial light modulator is formed on the conjugate plane. The light irradiation device according to claim 1 .

12. The position change device further includes a conjugation optical system that optically conjugates the spatial light modulator and the conjugate surface. The light irradiation device according to claim 11.

13. the object includes a light receiving portion of a light receiving device; The irradiation beam is irradiated to the light receiving section, The irradiation beam is a light beam for optical wireless communication with the light receiving device. The light irradiation device according to claim 1 .

14. a light receiving section that receives, via the optical member, an incident beam that is emitted from a light emitting section of a light transmitting device serving as the object and that is incident on the imaging optical system; The light irradiation device according to claim 1 .

15. The light receiving unit receives the incident beam via the conjugate surface. The light irradiation device according to claim 14.

16. The position changing device changes the position of the light receiving unit or changes the exit angle of the incident beam so that the incident beam passing through the conjugate surface is incident on the light receiving unit. The light irradiation device according to claim 14 or 15.

17. The position changing device moves the light receiving unit in a direction intersecting an optical axis of the imaging optical system on the light receiving unit side. The light irradiation device according to any one of claims 14 to 16.

18. the light generating device includes a light emitting unit that emits the irradiation beam, The positional relationship between the light receiving unit and the light emitting unit is fixed, The position changing device moves the light emitting unit and the light receiving unit in a direction intersecting an optical axis of the imaging optical system on the light receiving unit side. The light irradiation device according to any one of claims 14 to 17.

19. The imaging device includes a plurality of imaging pixels for capturing at least a portion of an image of the object; a light receiving pixel as the light receiving unit for receiving the incident beam, the light receiving pixel being different from the imaging pixel; The light receiving pixels receive the incident beam incident through the image plane. The light irradiation device according to claim 14.

20. the imaging device has a plurality of imaging pixels for capturing at least a portion of an image of the object; At least a portion of the plurality of imaging pixels are capable of receiving the incident beam; The imaging pixel capable of receiving the incident beam receives the incident beam incident through the image plane.

20. The light irradiation device according to claim 14 or 19.

21. The incident beam is a light beam for optical wireless communication with the light transmitting device. The light irradiation device according to any one of claims 14 to 20.

22. the light transmitting device is a light transmitting / receiving device including a light receiving unit, The incident beam is emitted from the light transmitting / receiving device, The irradiation beam is irradiated to the light receiving section, The incident beam and the illuminating beam are optical beams for optical wireless communication with the light transmitting / receiving device. The light irradiation device according to any one of claims 14 to 21.

23. The light generating device includes a light receiving unit that receives light generated by irradiating at least a part of an object with the irradiation beam from the imaging optical system via the imaging optical system and the optical member. The light irradiation device according to claim 1 .

24. The light receiving unit receives the light generated by irradiating at least a part of the object through the conjugate surface. The light irradiation device according to claim 23.

25. the light receiving unit is a light transmitting / receiving unit that emits the irradiation beam, a focusing optical system arranged on an optical path between the light transmitting / receiving unit and the optical member, the focusing optical system focusing the irradiation beam emitted from the light transmitting / receiving unit; The position change device has an incident angle change member that changes an incident angle of the illumination beam to the focusing optical system, and changes the position of the illumination beam on the conjugate plane by changing the incident angle of the illumination beam to the focusing optical system.

25. The light irradiation device according to claim 23 or 24.

26. The light transmitting / receiving unit receives light, which is generated by irradiating at least a part of the object, traveling along an optical path of the irradiation beam, via the light collecting optical system and the incident angle changing member. The light irradiation device according to claim 25.

27. The control device calculates the distance to the object based on the light reception result at the light receiving unit.

27. The light irradiation device according to claim 23.

28. The control device calculates an orientation of the object relative to the imaging optical system based on information about the change in position in the conjugate plane by the position change device.

28. The light irradiation device according to any one of claims 23 to 27.

29. When the object is a first object, an image of at least a part of a second object different from the first object is formed on the image plane by the imaging optical system; the imaging device captures an image of at least a portion of the first object and an image of at least a portion of the second object; When the irradiation beam is a first irradiation beam, the light generating device emits a second irradiation beam different from the first irradiation beam; the position changing device changes positions of the first illumination beam and the second illumination beam from the light generating device on the conjugate plane, thereby changing the irradiation positions of the first illumination beam and the second illumination beam emitted from the imaging optical system, The control device controls the position change device based on an imaging result of the imaging device to irradiate at least a part of the first object with the first irradiation beam emitted from the imaging optical system and to irradiate at least a part of the second object with the second irradiation beam emitted from the imaging optical system. The light irradiation device according to claim 1 .

30. a focusing optical system that is disposed on an optical path between a light emitting unit of the light generating device and the optical member and focuses the first irradiation beam and the second irradiation beam emitted from the light emitting unit, The position changing device has an incident angle changing member that changes an incident angle of each of the first illumination beam and the second illumination beam onto the focusing optical system, and changes the positions of each of the first illumination beam and the second illumination beam on the conjugate plane by changing the incident angles of each of the first illumination beam and the second illumination beam onto the focusing optical system.

30. The light irradiation device according to claim 29.

31. the first object includes a light receiving portion of a first light receiving device; the second object includes a light receiving portion of a second light receiving device; the first irradiation beam is irradiated onto a light receiving portion of the first light receiving device, the second irradiation beam is irradiated onto a light receiving portion of the second light receiving device, the first irradiation beam is a light beam for optical wireless communication with the first light receiving device, The second illumination beam is a light beam for optical wireless communication with the second light receiving device.

31. The light irradiation device according to claim 29 or 30.

32. a light receiving unit that receives, via the optical member, a first incident beam that is emitted from a light emitting unit of a first light transmitting device as the first object and enters the imaging optical system, and a second incident beam that is emitted from a light emitting unit of a second light transmitting device as the second object and enters the imaging optical system, the first incident beam is an optical beam for optically wirelessly communicating with a first light transmitting device, the second incident beam is an optical beam for optical wireless communication with a second light transmitting device; 31. The light irradiation device according to claim 29 or 30.

33. the first light transmitting device is a first light transmitting / receiving device including a light receiving unit, the second light transmitting device is a second light transmitting / receiving device including a light receiving unit, The first incident beam is emitted from the first light transmitting device, The second incident beam is emitted from the second light transmitting device, the first irradiation beam is irradiated onto a light receiving unit of the first light transmitting device, the second irradiation beam is irradiated onto a light receiving unit of the second light transmitting device, the first incident beam and the first illumination beam are optical beams for optical wireless communication with the first light transmitting / receiving device, The second incident beam and the second illuminating beam are optical beams for optical wireless communication with the second light transmitting / receiving device. The light irradiation device according to claim 32.

34. The light irradiation device according to claim 13 ; The light receiving device; Equipped with The optical wireless communication system enables the light emitting device and the light receiving device to communicate optically wirelessly by receiving the irradiation beam from the light emitting device at the light receiving portion of the light receiving device.

35. The light irradiation device according to claim 21 ; The light transmitting device; Equipped with The incident beam from the light transmitting device is received by the light receiving section of the light emitting device, thereby enabling the light transmitting device and the light emitting device to communicate optically wirelessly.

36. The light irradiation device according to claim 22; The light transmitting and receiving device; Equipped with An optical wireless communication system in which the light irradiation device irradiates the irradiation beam from the light irradiation device to the light receiving section of the light transmitting and receiving device, and the incident beam from the light transmitting and receiving device is received by the light receiving section of the light irradiation device, thereby enabling optical wireless communication between the light irradiation device and the light transmitting and receiving device.

37. The light irradiation device according to claim 31 ; The first light receiving device; The second light receiving device; Equipped with An optical wireless communication system in which the light irradiation device and the first light receiving device communicate optically wirelessly by receiving the first irradiation beam from the light irradiation device at the light receiving section of the first light receiving device, and the light irradiation device and the second light receiving device communicate optically wirelessly by receiving the second irradiation beam from the light irradiation device at the light receiving section of the second light receiving device.

38. The light irradiation device according to claim 32; The first light transmitting device; The second light transmitting device; Equipped with An optical wireless communication system in which the first light transmitting device and the light emitting device communicate optically wirelessly by receiving the first incident beam from the first light transmitting device at the light receiving section of the light emitting device, and the second light transmitting device and the light emitting device communicate optically wirelessly by receiving the second incident beam from the second light transmitting device at the light receiving section of the light emitting device.

39. The light irradiation device according to claim 33; The first light transmitting and receiving device; The second light transmitting and receiving device; Equipped with The optical wireless communication system includes: the light irradiation device irradiates the first irradiation beam from the light irradiation device to the light receiving section of the first light transmitting and receiving device; the first incident beam from the first light transmitting and receiving device is received by the light receiving section of the light irradiation device, thereby enabling the light irradiation device and the first light transmitting and receiving device to communicate optically wirelessly; and the light irradiation device irradiates the second irradiation beam from the light irradiation device to the light receiving section of the second light transmitting and receiving device; and the second incident beam from the second light transmitting and receiving device is received by the light receiving section of the light irradiation device, thereby enabling the light irradiation device and the second light transmitting and receiving device to communicate optically wirelessly.

40. A light irradiation method for irradiating an object with an irradiation beam from a light generating device, comprising: an optical step of emitting light incident via an imaging optical system toward an image plane of the imaging optical system, and emitting the irradiation beam from the light generating device incident via a conjugate plane conjugate to the image plane toward the imaging optical system; an imaging step of imaging at least a part of an image of the object formed on the image plane by the imaging optical system; a position changing step of changing a position of the irradiation beam from the light generating device on the conjugate plane to change an irradiation position of the irradiation beam emitted from the imaging optical system; a control step of controlling an irradiation position of the irradiation beam emitted from the imaging optical system based on an imaging result of the imaging step; having The control step controls an irradiation position of the irradiation beam emitted from the imaging optical system based on an imaging result of the imaging step, and irradiates at least a part of the object with the irradiation beam emitted from the imaging optical system. Light irradiation method.