Beam transmission system

Abstract

[Problem] To provide a beam transmission system capable of making it easy to recognize an irradiation position of a beam. [Solution] A beam transmission system 100 for transmitting a beam to a mobile body 2 comprises: a first emission part 11 that emits a detection beam to a reception part 21 included in the mobile body 2; an imaging element 12 that is provided between the first emission part 11 and the mobile body 2 and that controls a path of the detection beam; and a second emission part 13 that emits a transmission beam to the reception part 21. The imaging element 12 is characterized by being provided such that the intensity distribution of the detection beam shows that the intensity increases as the radial distance from the central axis c increases along a first direction from the second emission part 13 toward the reception part 21.

Description

Beam Delivery System

[0001] The present invention relates to a beam delivery system for delivering a beam to a moving object.

[0002] In recent years, research and development of non-terrestrial networks (NTNs) utilizing unmanned aerial vehicles such as drones and high altitude platform stations (HAPSs) has been attracting attention. Furthermore, in lunar exploration, research and development toward practical use of lunar gateways, lunar orbiting satellites, and lunar rovers in outer space has begun to accelerate, primarily among domestic and international research institutes and private companies. Along with this active movement, there is a demand for efficient and stable energy supply methods for unmanned aerial vehicles, lunar rovers, and the like, and techniques such as those disclosed in Patent Document 1 and Non-Patent Document 1 have been proposed.

[0003] For example, in conventional beam transmission technology, the detection and transmission beams are treated as a single beam. A quadrant photo diode (QD) sensor is used to detect the receiving photo diode (PD) on the receiving side. There are two methods: one is to estimate the center position of the beam from the difference in the amount of light received by the four diodes in the QD sensor, and then return this information to the transmitting side to control the beam direction; the other is to use this information to control the beam direction on the receiving side.

[0004] JP 2013-148626 A

[0005] Yoshinori Arimoto, "Design and Performance Evaluation of Free-Space Optical Communication System Using Single-Mode Fiber Coupling," IEICE Transactions on Electronics, Information and Communication Engineers, Vol. J91-C, No. 1, pp. 38-49, 2008.

[0006] When using the above-mentioned beams for detection, there are cases where a narrow-angle beam is used and cases where a wide-angle beam is used. Figure 6(a) shows the configuration of a beam transmission technology when a conventional narrow-angle beam Bn is used, and Figure 6(b) shows the configuration of a beam transmission technology when a conventional wide-angle beam Bw is used.

[0007] Here, when using the narrow-angle beam Bn emitted from the emission unit 511 of the emission device 501 shown in FIG. 6( a), the irradiation area of ​​the narrow-angle beam Bn needs to be narrower than the size of the QD sensor 521 of the moving object 502. However, if the irradiation area is too narrow, it is difficult for the narrow-angle beam Bn to accurately irradiate the QD sensor 521, which has the disadvantage of making it difficult to detect the position information of the narrow-angle beam Bn. This also makes it difficult to capture and track the moving object 502 using the narrow-angle beam Bn. Furthermore, if the narrow-angle beam Bn misses the QD sensor 521, it becomes necessary to perform beam capture and tracking again.

[0008] On the other hand, when using a wide-angle beam Bw emitted from the emitter 511 of the emitter 501 shown in FIG. 6(b), the irradiation area of ​​the wide-angle beam Bw becomes wider, making it easier to capture and track the moving object 502. However, because the irradiation area of ​​the wide-angle beam Bw becomes too wide, there is no difference in the amount of light received by the QD sensor 521, making it difficult to recognize the position information of the wide-angle beam Bw. Furthermore, since only a portion of the widened beam is received, the efficiency of beam transmission decreases. Therefore, if the beam divergence angle is increased, problems other than the recognition of the beam irradiation position may occur. These problems are not described or suggested in Patent Document 1 or Non-Patent Document 1, making it difficult to solve the above problems.

[0009] SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned problems, and has as its object to provide a beam delivery system that makes it easy to recognize the irradiation position of a beam.

[0010] In order to solve the above-mentioned problems, the inventors have invented a beam transmission system for transmitting a beam to a moving body. A first emitter emits a detection beam to a receiver included in the moving body. An imaging element is provided between the first emitter and the moving body and controls the path of the detection beam. A second emitter emits a transmission beam to the receiver. The imaging element is provided so that the intensity distribution of the detection beam becomes stronger as it moves away in the radial direction from a central axis along a first direction from the second emitter toward the receiver.

[0011] The beam transmission system of the first invention is a beam transmission system that transmits a beam to a moving body, and comprises: a first emitter that emits a detection beam to a receiving unit included in the moving body; an imaging element that is provided between the first emitter and the moving body and controls the path of the detection beam; and a second emitter that emits a transmission beam to the receiving unit, wherein the imaging element is provided so that the intensity distribution of the detection beam becomes stronger as it moves away radially from a central axis along a first direction from the second emitter toward the receiving unit.

[0012] A beam transmission system according to a second aspect of the present invention is the beam transmission system of the first aspect, characterized in that the beam divergence angle of the transmission beam is smaller than the beam divergence angle of the detection beam.

[0013] The beam transmission system of the third invention is characterized in that, in the second invention, the path of the detection beam is separated from the path of the transmission beam, and the imaging element includes a first element provided on the path of the detection beam and a second element provided on the path of the transmission beam.

[0014] A beam transmission system according to a fourth aspect of the present invention is the beam transmission system of the second aspect, characterized in that the wavelength of the detection beam is different from the wavelength of the transmission beam.

[0015] A beam transmission system according to a fifth aspect of the present invention is any one of the first to fourth aspects of the present invention, characterized in that the receiving unit includes a receiving diode that receives the detection beam and the transmission beam.

[0016] According to the first to fifth aspects of the present invention, the imaging element is arranged so that the intensity distribution of the detection beam becomes stronger as it moves away in the radial direction from the central axis along the first direction from the second emitter toward the receiver. This makes it easier to determine the irradiation position of the detection beam compared to when the maximum value of the intensity distribution of the detection beam is set at the central axis. This makes it easier to recognize the irradiation position of the beam. Furthermore, for example, it is possible to improve the transmission efficiency of the beam.

[0017] In particular, according to the second aspect of the present invention, the beam divergence angle of the transmission beam is smaller than that of the detection beam. This makes it easier to identify the beam irradiation position without reducing the beam intensity transmitted to the receiving unit. This makes it easier to identify the beam irradiation position and enables high efficiency beam transmission.

[0018] In particular, according to the third aspect of the present invention, the imaging element includes a first element provided on the path of the detection beam and a second element provided on the path of the transmission beam, which allows the paths of the beams to be controlled independently, making it easier to adjust the beam irradiation positions.

[0019] In particular, according to the fourth aspect of the present invention, the wavelength of the detection beam is different from the wavelength of the transmission beam, which makes it easier for the moving object to recognize the difference between the beams, thereby reducing misidentification when the beams are emitted simultaneously.

[0020] In particular, according to the fifth aspect of the present invention, the receiver includes a receiving diode for receiving the detection beam and the transmission beam. This simplifies the mobile body compared to when a diode is provided for each beam. This makes it easier to recognize the beam irradiation position and allows the mobile body to be made smaller.

[0021] FIG. 1 is a schematic diagram showing an example of a beam delivery system according to this embodiment. FIG. 2 is a flowchart showing an example of a beam delivery method according to this embodiment. FIG. 3(a) is a schematic diagram showing an example of a first emission step and a control step, and FIG. 3(b) is a schematic diagram showing an example of a second emission step. FIG. 4(a) is a schematic diagram showing a first modified example of the beam delivery system according to this embodiment, and FIG. 4(b) is a schematic diagram showing a second modified example of the beam delivery system according to this embodiment. FIG. 5 is a schematic diagram showing a third modified example of the beam delivery system according to this embodiment. FIGS. 6(a) and 6(b) are schematic diagrams showing conventional examples of beam delivery systems.

[0022] An example of a beam delivery system 100 and a beam delivery method according to an embodiment of the present invention will be described in detail below. Fig. 1 is a schematic diagram showing an example of a beam delivery system 100 according to this embodiment.

[0023] (Beam transmission system 100) The beam transmission system 100 transmits a beam to a mobile object 2, as shown in FIG. 1, for example. The beam transmission system 100 can be used, for example, to realize a terrestrial or non-terrestrial network for the mobile object 2. In the beam transmission system 100, energy is transmitted through space in the form of a beam. The transmitted energy is used as electrical energy in the form of almost direct current. In addition to the above, the transmitted energy can be converted into carrier wave energy for communication and modulated with transmission information for use. The beam transmission system 100 makes it easier to recognize the beam irradiation position compared to conventional systems. Furthermore, the beam transmission system 100 makes it possible to improve the transmission efficiency of beams, which is expected to result in improved communication conditions, for example.

[0024] The mobile object 2 represents, for example, a flying object such as a drone, HAPS, or satellite, or a mobile device spaced apart from the ground, such as a lunar rover. The mobile object 2 may also represent, for example, a vehicle such as an automobile traveling on the ground. The beam delivery system 100 is more effective when used in environments where communication, energy supply, and the like are more difficult than on the ground, such as the flying object or a mobile device spaced apart from the ground.

[0025] The various beams (detection beam Bf and transmission beam Bs) emitted toward the moving body 2 are electromagnetic waves such as light, terahertz waves, millimeter waves, and microwaves, and can be set arbitrarily depending on the application. The transmission beam Bs is used to supply energy to the moving body 2. The transmission beam Bs can play a role similar to that of known beam transmission technologies such as communications, and can be used by converting it into the energy of a carrier wave for communications and modulating it with transmission information.

[0026] The beam delivery system 100 includes a first emitting unit 11, an imaging element 12, and a second emitting unit 13. The beam delivery system 100 may include, for example, at least one of a control unit 3 and a beam switching mechanism 14. The beam delivery system 100 includes, for example, an emitting device 1 including the first emitting unit 11 and the imaging element 12, and a moving body 2.

[0027] The first emitter 11 emits a detection beam Bf to the receiver 21 included in the moving object 2. A known laser diode, for example, is used as the first emitter 11. The first emitter 11 has a size of, for example, about 5 to 10 mm, but can be set to any size depending on the application. Note that the distance from the first emitter 11 to the receiver 21 is approximately 100 m or less when a drone is used as the moving object 2, for example, but can be set to any distance depending on the type of moving object 2 and the characteristics of the beam.

[0028] For example, a plurality of first emitting units 11 may be provided (two in FIG. 1 ). The plurality of first emitting units 11 are provided, for example, around the second emitting unit 13. In this case, it is possible to more easily achieve acquisition and tracking of the detection beam Bf compared to the case where one first emitting unit 11 is used.

[0029] The imaging element 12 is provided between the first emission unit 11 and the moving body 2. The imaging element 12 controls the path of the detection beam Bf. For example, a biconvex lens or a known lens can be used as the imaging element 12. The imaging element 12 may be provided by combining a plurality of lenses, for example. The size of the imaging element 12 is, for example, about 5 to 10 cm, but can be set to any size depending on the application.

[0030] 3(a), the imaging element 12 is arranged so that the intensity distribution Bfi of the detecting beam Bf becomes stronger as it moves away in the radial direction from the central axis c along the first direction from the second emitting unit 13 toward the receiving unit 21. This makes it easier to determine the irradiation position of the detecting beam Bf compared to when the maximum value of the intensity distribution Bfi of the detecting beam Bf is set at the central axis c. This makes it easier to recognize the irradiation position of the beam.

[0031] The second emitting unit 13 emits a transmission beam Bs to the receiving unit 21. For example, a known laser diode is used as the second emitting unit 13. The second emitting unit 13 has a size of, for example, about 5 to 10 mm, but can be set to any size depending on the application.

[0032] The divergence angle of the transmission beam Bs is smaller than the divergence angle of the detection beam Bf, for example. In this case, the irradiation position of the detection beam Bf can be easily recognized without reducing the intensity of the transmission beam Bs emitted toward the receiver 21.

[0033] For example, the driving power of the second emitting unit 13 is greater than the driving power of the first emitting unit 11. Even in this case, the irradiation position of the detection beam Bf can be easily recognized without reducing the intensity of the transmission beam Bs emitted toward the receiving unit 21.

[0034] The receiver 21 receives the detection beam Bf and the transmission beam Bs. A QD sensor or a known diode can be used as the receiver 21 depending on the application. The receiver 21 has a size of, for example, about 5 to 10 cm, but can be set to any size depending on the application.

[0035] The receiver 21 includes, for example, one receiving diode for receiving the detection beam Bf and the transmission beam Bs. In this case, the mobile object 2 can be simplified compared to a case where two diodes are provided corresponding to each of the beams Bf and Bs. This makes it possible to mitigate the impact on mobile objects 2 that have strict weight restrictions, such as unmanned aerial vehicles such as drones and HAPS, lunar rovers, satellites, etc. The mobile object 2 may acquire information such as the intensity of each of the beams Bf and Bs received via the receiver 21 and transmit the information to the emitter 1 using known transmission technology.

[0036] For example, the control unit 3 controls the irradiation position of the detection beam Bf relative to the receiving unit 21. The control unit 3 may be provided as a beam control mechanism 31 in the emission device 1, or may be provided as a position control mechanism 32 in the moving body 2, for example.

[0037] For example, if the emitting device 1 is provided with a beam control mechanism 31, the radial distance from the central axis c and the degree of the intensity distribution Bfi of the detecting beam Bf may be controlled. This makes it possible to easily set the intensity distribution Bfi that makes it easy to recognize the beam irradiation position according to the distance from the emitting device 1 to the moving object 2.

[0038] For example, if the moving object 2 is provided with a position control mechanism 32, the receiving unit 21 may be controlled to optimize the irradiation position of the detection beam Bf. This makes it possible to easily set the irradiation position of the detection beam Bf according to the characteristics of each moving object 2 when using the detection beam Bf under the same conditions for multiple moving objects 2.

[0039] For example, the beam switching mechanism 14 switches between emitting the detection beam Bf and emitting the transmission beam Bs, making it possible to prevent interference between the detection beam Bf and the transmission beam Bs.

[0040] (Beam Delivery Method) Next, an example of a beam delivery method according to an embodiment of the present invention will be described. The beam delivery method includes a first emission step S110, a control step S120, and a second emission step S130, as shown in Fig. 2, for example. The beam delivery method is performed using a beam delivery system 100, for example.

[0041] <First Emission Step S110> In the first emission step S110, as shown in Fig. 3A, for example, a detection beam Bf is emitted to the receiving unit 21 included in the moving object 2. The detection beam Bf is emitted from, for example, a plurality of first emission units 11.

[0042] <Control Step S120> In control step S120, the transmission path of the detecting beam Bf is controlled via the imaging element 12 provided between the first emitter 11 and the moving object 2. In control step S120, the transmission path of the detecting beam Bf may be controlled, for example, by changing the emission direction of the detecting beam Bf from the first emitter 11 or by changing the installation conditions (e.g., angle, etc.) of the imaging element 12. Note that in control step S120, the transmission path of the detecting beam Bf may be controlled using, for example, the above-mentioned control unit 3.

[0043] The imaging element 12 is arranged so that the intensity distribution Bfi of the detecting beam Bf becomes stronger as it moves away from the central axis c in the radial direction. At this time, the transmission path of the detecting beam Bf is controlled so that the power received by the receiving unit 21 is minimized. This makes it easier to position the receiving unit 21 so that it overlaps with the central axis c, which indicates the minimum position of the intensity distribution Bfi.

[0044] <Second Emitting Step S130> In the second emitting step S130, as shown in Fig. 3B, for example, a transmission beam Bs is emitted to the receiving unit 21. The transmission beam Bs is emitted, for example, from the second emitting unit 13 and irradiated onto the receiving unit 21 via the imaging element 12. The second emitting step S130 is performed after switching between the emission of the detection beam Bf and the emission of the transmission beam Bs using, for example, the beam switching mechanism 14.

[0045] In the second emission step S130, for example, the maximum value of the intensity distribution Bsi of the transmission beam Bs is set to the central axis c, which makes it easier to accurately irradiate the transmission beam Bs to the receiving unit 21 that is arranged so as to overlap with the central axis c.

[0046] By performing the above-described steps, the beam transmission method of this embodiment is completed.

[0047] As described above, the beam transmission method has a major feature in that it uses a specially shaped detection beam Bf to efficiently detect the receiver 21, and then uses a transmission beam Bs to supply energy, communicate, etc. In particular, the transmission beam Bs can be converted into carrier wave energy for communication and modulated with transmission information for use. Furthermore, for example, the mobile unit 2 on the receiving side can have a simple configuration, which can lead to a reduction in the mass of the mobile unit 2.

[0048] (First Modification of Beam Delivery System 100) Next, a first modification of the beam delivery system 100 in this embodiment will be described. The difference between the above-described embodiment and the first modification is that the detection beam Bf and the transmission beam Bs are operated simultaneously. Note that a description of the same content as in the above-described embodiment will be omitted.

[0049] 4A, the detection beam Bf and the transmission beam Bs may be emitted simultaneously. In this case, in the beam transmission method, for example, the first emission step S110 and the second emission step S130 may be performed simultaneously, followed by the control step S120. Note that the same wavelength may be used for the detection beam Bf and the transmission beam Bs.

[0050] (Second Modification of Beam Delivery System 100) Next, a second modification of the beam delivery system 100 in this embodiment will be described. The difference between the above-described embodiment and the second modification is that different wavelengths are used for the detection beam Bf and the transmission beam Bs. Note that a description of the same content as in the above-described embodiment will be omitted.

[0051] 4B, the receiver 21 includes a transmission receiving element 21 a, a detection receiving element 21 b, and a filter 21 c. One or more of the detection receiving element 21 b and the filter 21 c may be provided.

[0052] The transmission receiving element 21a receives the transmission beam Bs. The detection receiving element 21b receives the detection beam Bf and is provided, for example, near the transmission receiving element 21a. The detection receiving element 21b is provided, for example, at least either above or below the transmission receiving element 21a. The filter 21c is provided on the surface of the detection receiving element 21b and suppresses the transmission beam Bs from passing through.

[0053] (Third Modification of Beam Delivery System 100) Next, a third modification of the beam delivery system 100 of this embodiment will be described. The difference between the above-described embodiment and the third modification is that the imaging element 12 includes different lenses for the beams Bf and Bs. Note that a description of the same content as in the above-described embodiment will be omitted.

[0054] 5, the path of the detecting beam Bf is separated from the path of the transmitting beam Bs. The imaging element 12 includes a detecting lens 12a (first element) and a transmitting lens 12b (second element), and may also include, for example, an auxiliary lens 12c.

[0055] As the detection lens 12a and the transmission lens 12b, for example, a biconvex lens or known lenses can be used. The auxiliary lens 12c controls only the path of the detection beam Bf. As the auxiliary lens 12c, for example, multiple lenses are provided at positions sandwiching the central axis c (for example, a pair of lenses positioned above and below the first emission part 11 along the central axis c). As the auxiliary lens 12c, for example, a doughnut-shaped lens exhibiting a hollow shape is used. In addition to the above, the auxiliary lens 12c may be replaced by a known lens capable of forming a ring-shaped (hollow) beam, such as an axicon lens. Each of the lenses 12a, 12b, and 12c may be provided by combining multiple lenses, for example.

[0056] The detection lens 12a is provided on the path of the detection beam Bf and is separated from, for example, the path of the transmission beam Bs. The transmission lens 12b is provided on the path of the transmission beam Bs and is separated from, for example, the path of the detection beam Bf. The auxiliary lens 12c is provided on the path of the detection beam Bf and is separated from, for example, the path of the transmission beam Bs. The lenses 12a, 12b, and 12c are provided, for example, from the emitting device 1 toward the moving body 2 in the order of the auxiliary lens 12c, the detection lens 12a, and the transmission lens 12b. In this case, the second emitting unit 13 is provided between the detection lens 12a and the transmission lens 12b.

[0057] In the above case, the detection beam Bf emitted from the first emitter 11 forms a hollow beam via the auxiliary lens 12c, and then forms multiple beams via the detection lens 12a, which are irradiated onto, for example, the detection receiving element 21b. Also, the transmission beam Bs emitted from the second emitter 13 is irradiated onto, for example, the transmission receiving element 21a via the transmission lens 12b. This allows the above-mentioned beam transmission method to be implemented with only one first emitter 11, which can lead to lower power consumption and cost reductions.

[0058] According to the above-described embodiment, the imaging element 12 is provided so that the intensity distribution Bfi of the detecting beam Bf becomes stronger as it moves away in the radial direction from the central axis c along the first direction from the second emitting unit 13 toward the receiving unit 21. This makes it easier to determine the irradiation position of the detecting beam Bf compared to when the maximum value of the intensity distribution Bfi of the detecting beam Bf is set at the central axis c. This makes it easier to recognize the irradiation position of the beam. Furthermore, for example, it becomes possible to improve the transmission efficiency of the beam.

[0059] Furthermore, according to the above-described embodiment, the beam divergence angle of the transmission beam Bs is smaller than the beam divergence angle of the detection beam Bf. This makes it easier to recognize the beam irradiation position without reducing the beam intensity transmitted to the receiver 21. This makes it easier to recognize the beam irradiation position and enables high efficiency beam transmission.

[0060] Furthermore, according to the above-described embodiment, the control unit 3 controls the irradiation position of the detecting beam Bf with respect to the receiving unit 21. This makes it possible to easily adjust the irradiation position of the beam.

[0061] Furthermore, according to the above-described embodiment, the imaging element 12 includes a first element (detection lens 12a) provided on the path of the detection beam Bf and a second element (transmission lens 12b) provided on the path of the transmission beam Bs. This allows the paths of the beams Bf and Bs to be controlled independently. This makes it possible to more easily adjust the beam irradiation positions.

[0062] Furthermore, according to the above-described embodiment, the wavelength of the detection beam Bf is different from the wavelength of the transmission beam Bs. This makes it easier for the moving object 2 to recognize the difference between the beams Bf and Bs. This makes it possible to prevent erroneous recognition when the beams Bf and Bs are emitted simultaneously.

[0063] Furthermore, according to the above-described embodiment, the receiver 21 includes a receiving diode for receiving the detection beam Bf and the transmission beam Bs. This simplifies the mobile object 2 compared to a case where a diode is provided for each beam. This makes it easier to recognize the beam irradiation position and also enables the mobile object 2 to be made smaller.

[0064] The operation of at least one of the above-described emission device 1 and mobile object 2 may be performed using known electronic devices including, for example, a processor such as a CPU (Central Processing Unit) and a storage device such as a RAM (Random Access Memory), and each of steps S110, S120, and S130 in the beam transmission method may be performed using known processing techniques using known electronic devices. The first emission step S110, the control step S120, and the second emission step S130 may be performed at any timing. For example, they may be performed at different times, or at least two steps may be performed simultaneously.

[0065] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0066] DESCRIPTION OF SYMBOLS 1: Emitting device 11: First emitting section 12: Imaging element 12a: Detection lens 12b: Transmission lens 12c: Auxiliary lens 13: Second emitting section 14: Beam switching mechanism 2: Mobile body 21: Receiving section 21a: Transmission receiving element 21b: Detection receiving element 21c: Filter 3: Control section 31: Beam control mechanism 32: Position control mechanism 100: Beam transmission system 501: Emitting device 502: Mobile body 511: Emitting section 521: QD sensor Bf: Detection beam Bfi: Intensity distribution Bn: Narrow-angle beam Bs: Transmission beam Bsi: Intensity distribution Bw: Wide-angle beam S110: First emitting step S120: Control step S130: Second emission step c: Central axis

Claims

1. A beam transmission system for transmitting a beam to a moving body, comprising: a first emission unit that emits a detection beam to a receiving unit included in the moving body; a pixel element provided between the first emission unit and the moving body for controlling a path of the detection beam; and a second emission unit that emits a transmission beam to the receiving unit, wherein the pixel element is provided such that an intensity distribution of the detection beam is strongly shown as it moves radially away from a central axis along a first direction from the second emission unit toward the receiving unit. A beam transmission system characterized by this.

2. The beam transmission system according to claim 1, wherein a beam divergence angle of the transmission beam is smaller than a beam divergence angle of the detection beam.

3. The path of the detection beam is separated from the path of the transmission beam, and the pixel element includes: a first element provided on the path of the detection beam; and a second element provided on the path of the transmission beam. The beam transmission system according to claim 2, characterized by this.

4. The beam transmission system according to claim 2, wherein a wavelength of the detection beam is different from a wavelength of the transmission beam.

5. The receiving unit includes a receiving diode that receives the detection beam and the transmission beam. The beam transmission system according to any one of claims 1 to 4, characterized by this.

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