Power receiving device, power supply device, optical power supply system

Abstract

To suppress the effect of irradiating power feeding light on which space transmission is performed.SOLUTION: An optical power feeding system 1B is designed to feed power from a power feeding device 110B to a power reception device 310B by means of space transmission of power feeding light 112. The power feeding device 110B has a light-emitting unit 111 that outputs the power feeding light 112 and an adjusting unit 150B that adjusts the beam diameter of the power feeding light 112 in a variable manner. The power reception device 310B has a light-receiving unit 311 that converts the received power feeding light 112 to power and a response unit 350B that responds to the power feeding device 110B in accordance with the suitability of the beam diameter of the power feeding light 112. The adjusting unit 150B progressively reduces the beam diameter of the power feeding light 112 from the beginning of its output and stops the reduction on the basis of the response.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a power receiving device, a power supply device, and an optical power supply system. [Background technology]

[0002] Recently, optical power supply systems have been studied in which electric power is converted into light (called power supply light) and transmitted, and the power supply light is converted into electrical energy for use as electric power. In view of the risk of damage to external objects when high-powered power supply light is irradiated onto them, conventional optical power supply systems have taken the following measures.

[0003] That is, conventional optical power supply systems have a configuration in which a first reflector and a second reflector are placed at both ends of an optical fiber, a semiconductor optical amplifier is placed between the first reflector and one end of the optical fiber, and an optical receiving module is placed outside the second reflector (see, for example, Patent Document 1). In the optical power supply system described above, two reflectors located on either side of the optical fiber and a semiconductor optical amplifier form a laser resonator, and the laser light (power supply light) output from the laser resonator is received by an optical receiving module and converted into electrical energy. On the other hand, if the optical fiber becomes disconnected and the laser light leaks outside, the first and second reflecting mirrors will no longer be able to resonate, and the power of the leaked laser light will be reduced and neutralized. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 032148 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when optical fibers are used in an optical power supply system, loss in the power supply light becomes large, and therefore, in recent years, power supply by space transmission has been considered. However, the conventional optical power supply system described above requires an optical fiber as an essential component, and therefore has a problem in that the influence of irradiation with power supply light cannot be suppressed in an optical power supply system that performs spatial transmission.

[0006] The present disclosure aims to suppress the influence of irradiation with power supply light that is transmitted through space. [Means for solving the problem]

[0007] The optical power supply system according to the present disclosure includes: An optical power supply system that supplies power from a power supply device to a power receiving device by spatial transmission of power supply light, the power supply device includes a light emitting unit that outputs the power supply light and an adjusting unit that variably adjusts a beam diameter of the power supply light, the power receiving device includes a light receiving unit that converts the received power supply light into electric power, and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light and stops the reduction based on the response. 、 The response unit makes the response based on the output of the light receiving unit. . Another optical power supply system according to the present disclosure includes: An optical power supply system that supplies power from a power supply device to a power receiving device by spatial transmission of power supply light, the power supply device includes a light emitting unit that outputs the power supply light and an adjusting unit that variably adjusts a beam diameter of the power supply light, the power receiving device includes a light receiving unit that converts the received power supply light into electric power, and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light and stops the reduction based on the response, The light emitting section is a semiconductor laser in which a semiconductor material constituting a semiconductor region that exhibits an optical-electrical conversion effect is used as a laser medium with a laser wavelength of 500 nm or less. Another optical power supply system according to the present disclosure includes: An optical power supply system that supplies power from a power supply device to a power receiving device by spatial transmission of power supply light, the power supply device includes a light emitting unit that outputs the power supply light and an adjusting unit that variably adjusts a beam diameter of the power supply light, the power receiving device includes a light receiving unit that converts the received power supply light into electric power, and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light and stops the reduction based on the response, The light receiving section is a photoelectric conversion element in which a semiconductor material constituting a semiconductor region that exhibits a light-to-electricity conversion effect is used as a laser medium with a laser wavelength of 500 nm or less.

[0008] The power supply device according to the present disclosure comprises: A power supply device that supplies power to a power receiving device by spatial transmission of power supply light, a light emitting unit that outputs the power supply light; and an adjusting unit that variably adjusts the beam diameter of the power supply light, The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light, and stops the reduction based on a response obtained in response to the beam diameter of the power supply light. 、 The light-emitting section is a semiconductor laser in which the semiconductor material constituting the semiconductor region that produces the optical-electrical conversion effect is used as a laser medium with a laser wavelength of 500 nm or less. .

[0009] The power receiving device according to the present disclosure comprises: The beam diameter of the power supply light is gradually reduced from the start of output. A power receiving device that receives power through spatial transmission of power supply light from a power supply device, a light receiving unit that converts the received power supply light into electric power; and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The response unit transmits a response to the power supply device indicating that the beam diameter of the power supply light is appropriate based on the power obtained by converting the power supply light by the light receiving unit. . [Effects of the Invention]

[0010] According to the present disclosure, it is possible to reduce the influence of irradiation with power supply light that performs spatial transmission. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of an optical power supply system according to a first embodiment of the present disclosure. [Figure 2] FIG. 10 is a configuration diagram of an optical power supply system according to a second embodiment of the present disclosure. [Figure 3] FIG. 10 is a configuration diagram of an optical power supply system according to a third embodiment of the present disclosure. [Figure 4] 4(A) to 4(C) are explanatory diagrams showing appropriate values ​​for the beam diameter of the power supply light. [Figure 5] 5(A) and 5(B) are explanatory diagrams showing abnormal patterns of the receiving state of the power supply light. [Figure 6] 10 is a flowchart showing the output control of the power supply light performed by the control device of the adjustment unit. [Figure 7]FIG. 10 is a configuration diagram of an optical power supply system according to a fourth embodiment of the present disclosure. [Figure 8] FIG. 10 is a configuration diagram of an optical power supply system according to a fifth embodiment of the present disclosure. [Figure 9] FIG. 10 is a configuration diagram of an optical power supply system according to a sixth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0013] (1) System Overview [First embodiment] As shown in FIG. 1, an optical power supply system 1A of this embodiment includes a power supply device (PSE: Power Sourcing Equipment) 110 and a power receiving device (PD: Powered Device) 310. The power supply device 110 is a device that converts electric power into optical energy and supplies the converted energy, and the power receiving device 310 is a device that receives optical energy and converts the optical energy into electric power.

[0014] In order to eliminate energy loss due to optical fiber transmission, the optical power supply system 1A supplies power from the power supply device 110 to the power receiving device 310 via spatial transmission of power supply light. This type of optical power supply method is called PoA (Power over Air). Note that spatial transmission here refers to transmission of power supply light in a state where only space exists, without an optical fiber being placed in the spatial transmission section between the power supply device 110 and the power receiving device 310. In this case, the space may be a vacuum state, or may contain air or other gases. In each of the following embodiments, unless otherwise specified, a case where the atmosphere exists between the power supply device 110 and the power receiving device 310 is illustrated.

[0015] Furthermore, the entire transmission path of the power supply light 112 between the power supply device 110 and the power receiving device 310 does not have to be configured as a spatial transmission section. For example, part of the transmission path may be configured as an optical fiber, and the remaining part may be configured as a spatial transmission path. However, in each of the following embodiments, unless otherwise specified, a case will be illustrated in which the entire transmission path of the power supply light between the power supply device and the power receiving device is configured as a spatial transmission section.

[0016] In addition, the transmission path of the power supply light between the power supply device 110 and the power receiving device 310 may be provided with a partition wall, protective fence, etc. to isolate the transmission path from the surroundings, but in each of the embodiments shown below, unless otherwise specified, examples are given of cases where such partition wall, protective fence, etc. are not provided.

[0017] The power supply device 110 includes a power supply semiconductor laser 111 as a light emitting section. The power supply device 110 is connected to a power source, and the power supply semiconductor laser 111 and the like are electrically driven. The power supply semiconductor laser 111 oscillates with the power from the power supply and outputs power supply light 112 . The power supply light 112 from the power supply device 110 propagates through the air and is input to the power receiving device 310 .

[0018] The power receiving device 310 includes a photoelectric conversion element 311 as a light receiving section. The photoelectric conversion element 311 converts the power supply light 112 transmitted through the air into electric power. The electric power converted by the photoelectric conversion element 311 is used as the driving power required within the power receiving device 310. Furthermore, the power receiving device 310 can output the electric power converted by the photoelectric conversion element 311 to an external device.

[0019] The semiconductor material constituting the semiconductor region that provides the light-to-electricity conversion effect of the power supply semiconductor laser 111 and the photoelectric conversion element 311 is a semiconductor having a short laser wavelength of 500 nm or less. Semiconductors with short laser wavelengths have a large band gap and high photoelectric conversion efficiency, which improves the photoelectric conversion efficiency on both the power generation side and the power receiving side of optical power supply, thereby improving the optical power supply efficiency. For this purpose, the semiconductor material may be, for example, a semiconductor material of a laser medium with a laser wavelength (fundamental wave) of 200 to 500 nm, such as diamond, gallium oxide, aluminum nitride, or GaN. In addition, a semiconductor having a band gap of 2.4 eV or more is used as the semiconductor material. For example, semiconductor materials for the laser medium, such as diamond, gallium oxide, aluminum nitride, and GaN, having a band gap of 2.4 to 6.2 eV, may be used. Note that the longer the wavelength of laser light, the better the transmission efficiency, and the shorter the wavelength, the better the photoelectric conversion efficiency. Therefore, for long-distance transmission, a semiconductor material for the laser medium with a laser wavelength (fundamental wave) of greater than 500 nm may be used. Furthermore, if photoelectric conversion efficiency is prioritized, a semiconductor material for the laser medium with a laser wavelength (fundamental wave) of less than 200 nm may be used. These semiconductor materials may be applied to either the power supply semiconductor laser 111 or the photoelectric conversion element 311. This improves the photoelectric conversion efficiency on the power supply side or the power receiving side, thereby improving the optical power supply efficiency.

[0020] As described above, the optical power supply system 1A transmits the power supply light 112 through space without using optical fiber as the transmission path. Generally, when optical fiber is used as the transmission path for the power supply light 112, the loss is about 30 dB / km, but when transmitted through space, the loss can be reduced to about 1 dB / km. Furthermore, when the semiconductor material constituting the semiconductor region that produces the optical-electrical conversion effect of the power supply semiconductor laser 111 is a semiconductor having a short laser wavelength of 500 nm or less, and when a semiconductor material for the laser medium such as diamond, gallium oxide, aluminum nitride, or GaN with a laser wavelength (fundamental wave) of 200 to 500 nm is used, loss in the optical fiber tends to occur depending on the length of the transmission distance, but in the case of spatial transmission, it is possible to significantly reduce loss.

[0021] Furthermore, optical fiber is not used as the transmission path for the power supply light 112, but rather, space transmission is performed using the air. Therefore, there is no restriction on the handling power regulated for optical fiber, and the power supply light 112 can be output with a large output, making it possible to supply more power to the power receiving device 310.

[0022] Second Embodiment As shown in FIG. 2, the optical power supply system 1 of this embodiment includes a power over air (PoA) system that performs spatial transmission and an optical communication system, and is equipped with a first data communication device 100 including a power supply device (PSE: Power Sourcing Equipment) 110, an optical fiber cable 200, and a second data communication device 300 including a power receiving device (PD: Powered Device) 310. The power supply device 110 includes a power supply semiconductor laser 111. In addition to the power supply device 110, the first data communication device 100 includes a transmitting unit 120 that performs data communication, and a receiving unit 130. The first data communication device 100 corresponds to a data terminal equipment (DTE), a repeater, or the like. The transmitting unit 120 includes a signal semiconductor laser 121 and a modulator 122. The receiving unit 130 includes a signal photodiode 131.

[0023] The optical fiber cable 200 includes an optical fiber 250 that forms a transmission path for signal light.

[0024] The power receiving device 310 includes a photoelectric conversion element 311. The second data communication device 300 includes, in addition to the power receiving device 310, a transmitting unit 320, a receiving unit 330, and a data processing unit 340. The second data communication device 300 corresponds to a power end station or the like. The transmitting unit 320 includes a signal semiconductor laser 321 and a modulator 322. The receiving unit 330 includes a signal photodiode 331. The data processing unit 340 is a unit that processes a received signal. Furthermore, the second data communication device 300 is a node in a power supply network. Alternatively, the second data communication device 300 may be a node that communicates with other nodes.

[0025] The first data communication device 100 is connected to a power source, and the power supply semiconductor laser 111, the signal semiconductor laser 121, the modulator 122, the signal photodiode 131, etc. are electrically driven. The first data communication device 100 is a node in a power supply network. Alternatively, the first data communication device 100 may be a node that communicates with other nodes. The power supply semiconductor laser 111 oscillates with the power from the power supply and outputs power supply light 112 .

[0026] The photoelectric conversion element 311 converts the spatially transmitted power supply light 112 into electric power. The electric power converted by the photoelectric conversion element 311 is used as driving power for the transmitting unit 320, the receiving unit 330, and the data processing unit 340, as well as for driving power required for other components in the second data communication device 300. Furthermore, the second data communication device 300 may be capable of outputting the electric power converted by the photoelectric conversion element 311 to an external device.

[0027] On the other hand, a modulator 122 of the transmitting section 120 modulates a laser beam 123 from a signal semiconductor laser 121 based on transmission data 124 and outputs the modulated laser beam 123 as a signal beam 125 . The signal photodiode 331 of the receiving section 330 demodulates the signal light 125 transmitted through the optical fiber cable 200 into an electrical signal and outputs it to the data processing unit 340. The data processing unit 340 transmits data represented by the electrical signal to the node, and at the same time receives data from the node and outputs it to the modulator 322 as transmission data 324. A modulator 322 of the transmitting section 320 modulates a laser beam 323 from a signal semiconductor laser 321 based on transmission data 324 and outputs the modulated laser beam 323 as a signal beam 325 . The signal photodiode 131 of the receiving unit 130 demodulates the signal light 325 transmitted through the optical fiber cable 200 into an electrical signal and outputs it. Data represented by the electrical signal is transmitted to the node, while data from the node is transmitted as transmission data 124.

[0028] (2) Application of a configuration that optimizes the beam diameter of the power supply light Next, an optical power supply system to which a configuration for optimizing the beam diameter of the power supply light 112 is applied will be described. In each embodiment described below, the same components as those in the first or second embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0029] Third Embodiment FIG. 3 is a configuration diagram showing an optical power supply system 1B according to a third embodiment, to which a configuration for optimizing the beam diameter of the power supply light 112 is applied. The optical power supply system 1B of the third embodiment includes a power supply device 110B and a power receiving device 310B.

[0030] The power supply device 110B includes a power supply semiconductor laser 111 and an adjusting section 150B that variably adjusts the beam diameter of the power supply light 112. The power receiving device 310B includes a photoelectric conversion element 311 and a response unit 350B that responds to the power supply device 110B depending on whether the beam diameter of the power supply light 112 is appropriate.

[0031] The adjustment unit 150B has an optical element 151B that changes the beam diameter of the power supply light 112 of the power supply semiconductor laser 111, a control device 152B that controls the optical element 151B, and a response receiving unit 153B that receives a response indicating the appropriate state of the beam diameter from the response unit 350B of the power receiving device 310B.

[0032] The optical element 151B is configured by, for example, a beam expander, a variable-focus lens, etc. The optical element 151B has a plurality of lenses arranged along the optical axis of the power supply light 112 and an actuator that moves some of the lenses in the optical axis direction. By controlling the position of the movable lens in the optical axis direction by the actuator, the beam diameter of the power supply light 112 can be adjusted arbitrarily. The actuator may be an actuator whose movement amount can be arbitrarily controlled based on an external control command, such as a stepping motor or a voice coil motor. The adjuster 150B may also be configured to include a collimator lens, which can collimate the power supply light 112 to be output, and can adjust the beam diameter of the power supply light 112 made of the collimated light.

[0033] The control device 152B controls the power supply semiconductor laser 111 and the optical element 151B, and can control the output and stop of the power supply light 112 to the power supply semiconductor laser 111, and adjust the beam diameter of the power supply light 112 by the optical element 151B. The control device 152B may be configured from a microcomputer or a sequencer that uses analog or digital circuits.

[0034] The response receiving unit 153B is made up of, for example, a photodiode, receives the signal light 112B that is the response from the responding unit 350B of the power receiving device 310B, demodulates it into an electric signal, and outputs it to the control device 152B. The signal light 112B from the responder 350B of the power receiving device 310B may be a response indicating the appropriate state of the beam diameter, a notification of an abnormality in the light receiving state of the power supply light 112, or a notification of permission to resume the power supply light 112 from a stopped state. These will be described later.

[0035] The response section 350B has a signal semiconductor laser 351B that outputs laser light as the signal light 112B, a control device 352B that causes the signal semiconductor laser 351B to output the signal light 112B in accordance with predetermined conditions, and a standby power supply 353B.

[0036] The control device 352B monitors the power output by the photoelectric conversion element 311 in response to the received power supply light 112, and determines whether the beam diameter of the power supply light 112 is appropriate and whether there is an abnormality in the light reception state. Then, based on the above-mentioned judgment results, the control device 352B controls the signal semiconductor laser 351B to output a signal light 112B as a response indicating the appropriate state of the beam diameter or a notification of an abnormality in the light receiving state of the power supply light 112. The control device 352B may be configured from a microcomputer, or may be configured from a sequencer that uses analog or digital circuits.

[0037] The standby power supply 353B is a power supply for causing the signal semiconductor laser 351B to output the signal light 112B as a notification of the abnormality in the light receiving state of the power supply light 112 when an abnormality occurs in the light receiving state of the power supply light 112. If an abnormality occurs in the light receiving state of the power supply light 112, there is a risk that the signal semiconductor laser 351B will not be able to obtain power from the power supply light 112 to output the signal light 112B, so in such a case, the standby power supply 353B supplies power. The standby power supply 353B may be a primary battery, a secondary battery, or a capacitor. When the standby power supply 353B is configured as a secondary battery or a capacitor, it may be configured to charge when the power supply light 112 is received.

[0038] 4(A) to 4(C) are explanatory diagrams showing the appropriate value of the beam diameter s of the power supply light 112. FIG. The power supply semiconductor laser 111 emits power supply light 112 with a constant output. As shown in Figures 4(A) and 4(B), if the beam diameter s of the power supply light 112 at the photoelectric conversion element 311 of the power receiving device 310B is larger than the light receiving surface 311a of the photoelectric conversion element 311 of the power receiving device 310B, part of the power supply light 112 is not converted into electric power, and the optical power supply efficiency decreases. On the other hand, when the beam diameter s of the power supply light 112 is smaller than the light receiving surface 311a of the photoelectric conversion element 311, the entire power supply light 112 can be converted into electric power.

[0039] On the other hand, when the beam diameter s of the power supply light 112 becomes smaller, the energy density in the irradiation range becomes higher, so if a foreign object (substance) enters the irradiation range of the power supply light 112, the irradiated area may be damaged by heat generation. Therefore, as shown in Fig. 4(C), by setting the beam diameter s of the power supply light 112 to the maximum diameter within the range that fits within the light receiving surface 311a of the photoelectric conversion element 311, it is possible to maintain high optical power supply efficiency and suppress the influence of foreign matter. In other words, it can be said that the optimum value for the beam diameter s of the power supply light 112 in Fig. 4(C) is the maximum diameter within the range that fits within the light receiving surface 311a of the photoelectric conversion element 311.

[0040] 5A and 5B are explanatory diagrams showing abnormal patterns of the receiving state of the power supply light 112. FIG. If a foreign object h enters the spatial path of the power supply light 112 from the power supply semiconductor laser 111 of the power supply device 110B to the photoelectric conversion element 311 of the power receiving device 310B, the output of the photoelectric conversion element 311 will be significantly reduced depending on whether the power supply light 112 is completely blocked as shown in Figure 5(A) or a portion of the power supply light 112 is blocked as shown in Figure 5(B). Therefore, the control device 152B of the response unit 350B of the power receiving device 310B monitors the output of the photoelectric conversion element 311 after the start of power supply, and determines whether an abnormality has occurred in the light receiving state of the power supply light 112 shown in Figure 5(A) or Figure 5(B). The control device 152B may set a threshold value for the output of the photoelectric conversion element 311 and determine that an abnormality has occurred in the light receiving state if the output falls below the threshold value, or may set a threshold value for the rate of decrease in the output of the photoelectric conversion element 311 and determine that an abnormality has occurred in the light receiving state if the rate of decrease in the output of the photoelectric conversion element 311 exceeds the threshold value.

[0041] FIG. 6 is a flowchart showing the output control of the power supply light 112 performed by the control device 152B of the adjustment unit 150B. The control performed by the control device 152B of the adjustment section 150B and the corresponding control performed by the control device 352B of the response section 350B will be described in detail with reference to FIGS. 4(A) to 6. FIG.

[0042] First, the control device 152B of the adjustment unit 150B controls the optical element 151B of the adjustment unit 150B so that the beam diameter becomes an initial value that is clearly larger than the light receiving surface 311a of the photoelectric conversion element 311, and starts outputting the power supply light 112 (step S1). In the control device 152B, when the vertical and horizontal widths of the light receiving surface 311a of the photoelectric conversion element 311 are known, a value larger than either the vertical or horizontal width is registered as the initial value. In addition, when the vertical and horizontal widths of the light receiving surface 311a are not known, a value larger than a value that can be taken within the range of common technical knowledge for the photoelectric conversion element 311 of the power receiving device 310B is registered as the initial value in the control device 152B.

[0043] Then, the control device 152B starts irradiating the power supply light 112 and controls the optical element 151B to gradually reduce the beam diameter of the power supply light 112 (step S3). At this time, as shown in FIG. 4(A), on the power receiving device 310B side, the power supply light 112 is also irradiated to the outside of the light receiving surface 311a of the photoelectric conversion element 311, so the amount of power output from the photoelectric conversion element 311 is smaller than the output of the power supply light 112. Furthermore, as shown in FIG. 4B, when the beam diameter of the power supply light 112 is gradually reduced, the density of the power supply light 112 on the light receiving surface 311a gradually increases, and therefore the amount of power output from the photoelectric conversion element 311 gradually increases.

[0044] When the photoelectric conversion element 311 starts receiving the power supply light 112, the control device 352B of the response unit 350B receives power and monitors the change in the power output by the photoelectric conversion element 311 from the start of receiving the power supply light 112. Then, as the beam diameter of the power supply light 112 gradually decreases, as shown in FIG. 4(C), when the beam diameter of the power supply light 112 reaches a size that fits within the inner range of the light receiving surface 311a (the appropriate value of the beam diameter of the power supply light 112 described above), the power output by the photoelectric conversion element 311 stops increasing gradually and becomes constant. When the control device 352B of the response unit 350B detects that the gradual increase in the power output by the photoelectric conversion element 311 has stopped, it recognizes that the beam diameter of the power supply light 112 has become a size that fits within the inner range of the light receiving surface 311a, and controls the signal semiconductor laser 351B to output signal light 112B as a response indicating the appropriate state of the beam diameter.

[0045] On the other hand, after the start of reduction of the beam diameter of the power supply light 112, the control device 152B of the adjustment unit 150B monitors the reception of the signal light 112B from the responder 350B by the response receiver 153B (step S5). If reception of the signal light 112B is not detected, the beam diameter of the power supply light 112 continues to be reduced, and if reception of the signal light 112B is detected, it is recognized that the beam diameter of the power supply light 112 has reached the appropriate value, and the control device 152B stops reducing the beam diameter of the power supply light 112 by the optical element 151B and maintains the beam diameter at the appropriate value (step S7).

[0046] After outputting the signal light 112B as a response indicating the appropriate state of the beam diameter, the control device 352B of the response unit 350B monitors the power output by the photoelectric conversion element 311 for a drop or sudden drop in power due to the interruption of the power supply light 112 by a foreign object h as shown in FIG. 5(A) or the partial blocking of the power supply light 112 by a foreign object h as shown in FIG. 5(B). When a drop or sudden drop in power is detected, the control device 352B of the response unit 350B causes the signal semiconductor laser 351B to output a signal light 112B as a notification that the power supply light 112 is abnormal in its receiving state.

[0047] On the other hand, after the control to maintain the beam diameter of the power supply light 112 at an appropriate value, the control device 152B of the adjustment unit 150B again monitors the reception of the signal light 112B from the responder 350B by the response receiver 153B (step S9). Then, when reception of the signal light 112B is detected again, the occurrence of an abnormality in the light receiving state of the power supply light 112 is recognized, and the control device 152B stops the output of the power supply light 112 from the power supply semiconductor laser 111 (step S11).

[0048] Thereafter, the control device 152B of the adjustment unit 150B periodically outputs the power supply light 112 from the power supply semiconductor laser 111 for a short time to check whether or not the power supply can be resumed (step S13).

[0049] In response to this, the control device 352B of the response unit 350B monitors whether or not there is power due to reception of the power supply light 112 by the photoelectric conversion element 311 using power supplied from the backup power source 353B, since power supply by the power supply light 112 is stopped and power supply is lost. At this point, if the abnormality in the light receiving state, such as the blocking of the power supply light 112 by the foreign object h shown in FIG. 5(A) or the partial blocking of the power supply light 112 by the foreign object h shown in FIG. 5(B), has been resolved, the power supply light 112 is received to confirm whether power supply can be resumed, and a certain level of power is detected from the photoelectric conversion element 311. Therefore, the control device 352B of the response unit 350B can recognize that the abnormality in the light receiving state of the power supply light 112 has been resolved, and causes the signal semiconductor laser 351B to output the signal light 112B as a notice of permission to resume.

[0050] Meanwhile, the control device 152B of the adjustment unit 150B monitors the reception of the signal light 112B from the response unit 350B by the response receiving unit 153B every time it outputs the power supply light 112 to check whether power supply can be resumed (step S15). If the signal light 112B is not received from the responder 350B, the process returns to step S13 and the power supply light 112 is output to check whether power supply can be resumed. If reception of the signal light 112B from the responder 350B is detected, the process returns to step S7 and restarts output of the power supply light 112 with the above-mentioned appropriate value of the beam diameter.

[0051] As described above, in the optical power supply system 1B, the optical element 151B of the adjustment unit 150B gradually reduces the beam diameter of the power supply light 112 from the start of output of the power supply light 112, and controls to stop the reduction based on the signal light 112B obtained as a response depending on whether the beam diameter of the power supply light 112 is appropriate. This allows the beam diameter of the power supply light 112 to be optimized, and makes it possible to reduce or suppress the effect of foreign matter h that has entered the irradiation range of the power supply light 112 while maintaining high optical power supply efficiency.

[0052] Furthermore, in the optical power supply system 1B, the power receiving device 310B has a response unit 350B that responds depending on whether the beam diameter of the power supply light 112 is appropriate. Therefore, the power receiving device 310B can determine whether the beam diameter is appropriate, and the beam diameter of the power supply light 112 can be easily monitored, thereby enabling better optimization of the beam diameter of the power supply light 112. In particular, the response unit 350B responds based on the output of the photoelectric conversion element 311, so that it is possible to detect whether the beam diameter of the power supply light 112 is appropriate by utilizing an existing configuration, thereby eliminating the need for a dedicated detection device, reducing the number of parts, thereby reducing costs, and enabling effective use of device resources.

[0053] Furthermore, in the optical power supply system 1B, the power receiving device 310B is provided with a response unit 350B that functions as a notification unit that notifies the power supply device 110B of an abnormality in the light receiving state of the power supply light 112 in the photoelectric conversion element 311, and the power supply device 110B stops outputting the power supply light 112 in response to the notification. Therefore, if the abnormality in the light receiving state is caused by a foreign object h that has entered the irradiation range of the power supply light 112, the irradiation of the power supply light 112 onto the foreign object h can be quickly stopped, and in this case too, it is possible to reduce or suppress the impact of the foreign object h that has entered the irradiation range of the power supply light 112.

[0054] In the optical power supply system 1B of the third embodiment, a configuration is exemplified in which the signal light 112B for response, abnormality notification, and restart permission is transmitted between the adjustment unit 150B and the response unit 350B by spatial transmission, but the signal light 112B may also be transmitted using optical fiber. Furthermore, the response, abnormality notification, and restart permission notification between the adjustment unit 150B and the response unit 350B are not limited to optical signals, and may be sent by radio communication or wired communication using electrical signals.

[0055] [Fourth embodiment] 7 is a configuration diagram showing an optical power supply system 1C according to a fourth embodiment, which employs a configuration for optimizing the beam diameter of the power supply light 112. In the fourth embodiment, the same components as those in the other embodiments already described are designated by the same reference numerals, and redundant description will be omitted.

[0056] The optical power supply system 1C includes a power supply device 110C and a power receiving device 310C.

[0057] The power supply device 110C includes a power supply semiconductor laser 111 and an adjustment unit 150C that variably adjusts the beam diameter of the power supply light. The power receiving device 310C includes a photoelectric conversion element 311 and a response unit 350C that responds to the power supply device 110C depending on whether the beam diameter of the power supply light 112 is appropriate.

[0058] The adjustment unit 150C has an optical element 151B that changes the beam diameter of the power supply light 112 of the power supply semiconductor laser 111, a control device 152C that controls the optical element 151B, and a response receiving unit 153C that receives responses and notifications from the response unit 350C of the power receiving device 310C.

[0059] The response from the response unit 350C of the power receiving device 310C is made by the signal light 112C consisting of reflected light of the power supply light 112. For this reason, the response receiving unit 153C of the adjustment unit 150C is made up of a photoelectric conversion element or a photodiode that receives the signal light 112C and inputs a detection signal to the control device 152C.

[0060] The control device 152C controls the power supply semiconductor laser 111 and the adjustment unit 150B, and the control over these and the processing performed when the response receiving unit 153C receives the signal light 112C are the same as those of the control device 152B described above. This control device 152C may also be configured from a microcomputer, or may be configured from a sequencer that uses analog or digital circuits.

[0061] The response unit 350C has a reflecting device 351C equipped with a movable reflector that reflects the power supply light 112 toward the response receiving unit 153C of the adjustment unit 150C, a control device 352C that controls the reflecting device 351C, and a standby power supply 353B.

[0062] The control device 352C determines whether the beam diameter of the power supply light 112 is appropriate and whether there is an abnormality in the light receiving state, using the same method as the control device 352B described above. The control device 352C may also be configured from a microcomputer, or may be configured from a sequencer that uses analog or digital circuits.

[0063] The reflecting device 351C is disposed in front of the light receiving surface 311a of the photoelectric conversion element 311, and supports the reflector movably between a reflecting position inside the transmission path of the power supply light 112 and a retracted position outside the transmission path. The reflecting device 351C has an actuator that moves the reflector between the two positions, and the control device 352C controls the movement of the reflector to each position. The reflector in the reflecting position can reflect the power supply light 112 from the power supply device 110C toward the response receiving section 153C of the adjustment section 150C, and can transmit the signal light 112C as reflected light to the adjustment section 150C.

[0064] With the above configuration, the response unit 350C also functions as a notification unit that notifies the power supply device 110C of an abnormality in the light receiving state of the power supply light 112.

[0065] With the above configuration, the optical power supply system 1C can perform the same control as the output control of the power supply light 112 shown in FIG. 6 performed by the control device 152B of the adjustment unit 150B of the optical power supply system 1B. However, if an abnormality in the light receiving state occurs in which the power supply light 112 is completely blocked as shown in Fig. 5(A), it is not possible to transmit the signal light 112C consisting of the reflected light of the power supply light 112 (in the case of the abnormality in the light receiving state as shown in Fig. 5(B), it is possible to transmit the signal light 112C). Therefore, when controlling the output of the power supply light 112 in the optical power supply system 1C, the processes from step S9 onwards in Fig. 6 may be omitted.

[0066] With the above configuration, the optical power supply system 1C has the same technical effect as the optical power supply system 1B, and the responder 350C does not require a component for communication such as a signal semiconductor laser, etc. This reduces the consumption of power obtained from the power supply light 112, making it possible to supply power for other purposes.

[0067] Fifth Embodiment 8 is a configuration diagram showing an optical power supply system 1D according to a fifth embodiment, which employs a configuration for optimizing the beam diameter of the power supply light 112. In the fifth embodiment, only the differences from the optical power supply system 1C will be described, and the same components as those in the other embodiments already described will be assigned the same reference numerals and redundant description will be omitted.

[0068] The optical power supply system 1D differs from the optical power supply system 1C in that a reflector 351D serving as a response unit is provided around the light receiving surface 311a of the photoelectric conversion element 311 of the power receiving device. The reflector 351D is arranged at the outer edge of the light receiving surface 311a of the photoelectric conversion element 311 so that there is almost no gap between the reflector 351D and the outer edge of the light receiving surface 311a, and is configured so that all of the power supply light 112 irradiated to the outside of the light receiving surface 311a is reflected toward the response receiving unit 153C of the adjustment unit 150C.

[0069] In the optical power supply system 1D, when the output of the power supply light 112 starts, the power supply light 112 irradiated to the outside of the light-receiving surface 311a is reflected by the reflector 351D, and the reflected light is incident on the response receiving unit 153C of the adjustment unit 150C as the signal light 112D. Therefore, while the signal light 112D is detected by the response receiving unit 153C, the control device 152C can recognize that the beam diameter of the power supply light 112 is larger than the appropriate value. Then, as the power supply light 112 gradually shrinks, it fits within the light receiving surface 311a, is not reflected by the reflector 351D, the signal light 112D is no longer detected by the response receiving unit 153C, and the control device 152C can recognize that the beam diameter of the power supply light 112 has reached the appropriate value. In other words, the disappearance of the signal light 112D corresponds to a response indicating that the beam diameter of the power supply light 112 has reached the appropriate value. When this response is received, the reduction of the beam diameter of the power supply light 112 is stopped, and control is performed to maintain the beam diameter at an appropriate value.

[0070] The optical power supply system 1D can optimize the beam diameter of the power supply light 112 through the above control, and can obtain technical effects by optimizing the beam diameter, similar to the optical power supply system 1C. Furthermore, with the above configuration, the optical power supply system 1D can have the response unit configured only with the reflector 351D, which simplifies the configuration of the response unit and eliminates power consumption by the response unit, significantly reducing the consumption of power obtained from the power supply light 112 and making it possible to supply more power for other uses.

[0071] Sixth Embodiment FIG. 9 is a configuration diagram showing an optical power supply system 1E according to a sixth embodiment to which a configuration for optimizing the beam diameter of the power supply light 112 is applied. The optical power supply system 1E of the sixth embodiment is configured by adding an adjustment unit 150E to the first data communication device 100 in the optical power supply system 1 of the second embodiment, and giving the second data communication device 300 the functions of a response unit and a notification unit. In the following description, only the differences between the optical power supply system 1E and the optical power supply system 1 will be described.

[0072] The adjustment unit 150E includes the optical element 151B and a control device 152E that controls the optical element 151B and the semiconductor laser 111 for power supply. The control device 152E executes the same output control of the power supply light 112 (FIG. 6) as the control device 152B of the optical power supply system 1B described above.

[0073] In the optical power supply system 1E, the processes performed by the response unit (processing to monitor the change in the power output by the photoelectric conversion element 311 from the start of reception of the power supply light 112, which is executed in conjunction with the output control of the power supply light 112, processing to monitor abnormalities in the light reception state of the power supply light 112, and processing to determine whether the abnormality in the light reception state has been resolved) are performed by the data processing unit 340 possessed by the second data communication device 300. Furthermore, the response from the responding unit indicating the appropriate state of the beam diameter from the power receiving device 310 of the second data communication device 300, and the notification of an abnormality in the light receiving state of the power supply light 112 and the notification of permission to resume the power supply light 112 from a stopped state, are made by signal light 325 emitted by the transmitting unit 320 of the second data communication device 300. These signals are received by the receiving unit 130 of the first data communication device 100 and input to the control device 152E. As a result, the control device 152E can execute the same output control of the power supply light 112 (FIG. 6) as the control device 152B described above.

[0074] With the above configuration, the optical power supply system 1E can achieve the same technical effects as the optical power supply system 1B.

[0075] In the optical power supply system 1E, the transmitting unit 320 includes the modulator 322, and the modulator 322 can transmit the signal light 325 to the adjusting unit 150E by including information for individually identifying the response indicating the appropriate beam diameter, the notification of an abnormality in the light receiving state of the power supply light 112, and the notification of permission to resume the power supply light 112 from a stopped state. In this way, the adjusting unit 150E, upon receiving the signal light 325, can identify whether the received signal light 325 indicates a response indicating the appropriate beam diameter, the notification of an abnormality in the light receiving state of the power supply light 112, or the notification of permission to resume the power supply light 112 from a stopped state. In the optical power supply system 1B described above, the response indicating the appropriate state of the beam diameter, the notification of an abnormality in the light-receiving state, and the notification of permission to resume all use the same signal light 112B. The control device 152B is configured to execute control corresponding to each response or notification depending on the processing step (timing) in which the signal light 112B was received, without determining whether the received signal light 112B is a response indicating the appropriate state of the beam diameter, a notification of an abnormality in the light-receiving state, or a notification of permission to resume. In contrast, if the modulator 322 of the optical power supply system 1E is capable of individually distinguishing between the response indicating the appropriate state of the beam diameter, the notification of an abnormality in the light receiving state of the power supply light 112, and the notification of permission to resume the power supply light 112 from a stopped state, there is no longer any restriction that these responses or notifications must be sent only at a predetermined processing step (timing), so that the judgment of whether the beam diameter of the power supply light 112 is appropriate and the judgment of an abnormality in the light receiving state can both be performed at any timing, making it possible to quickly control them.

[0076] In the sixth embodiment, the signal light 125, 325 is transmitted through the optical fiber cable 200, but the signal light 125, 325 may also be transmitted through space.

[0077] [others] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. For example, instead of using the entire transmission path of the power supply light 112 for spatial transmission, part of the transmission path may be configured using optical fiber and the remaining part may be configured for spatial transmission. In this case, it is preferable to provide optical element 151B closest to power supply device 110 in the spatial transmission section. Furthermore, for example, the transmitting units 120 and 320 modulate the laser light by a so-called external modulation method in which the laser light output from the signal semiconductor laser is modulated by a modulator, but the laser light may also be modulated by a so-called direct modulation method in which the signal semiconductor laser directly modulates the laser light and outputs it.

[0078] An embodiment of the present disclosure will be described below. (1) An optical power supply system that supplies power from a power supply device to a power receiving device by spatial transmission of power supply light, the power supply device includes a light emitting unit that outputs the power supply light and an adjusting unit that variably adjusts a beam diameter of the power supply light, the power receiving device includes a light receiving unit that converts the received power supply light into electric power, and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light and stops the reduction based on the response.

[0079] (2) In the optical power supply system of (1), The response unit makes the response based on the output of the light receiving unit.

[0080] (3) In the optical power supply system of (1) or (2) above, a notification unit that notifies the power supply device of an abnormality in the receiving state of the power supply light at the light receiving unit, In response to the notification, the power supply device stops outputting the power supply light.

[0081] (4) In any one of the optical power supply systems (1) to (3) above, The light emitting section is a semiconductor laser in which a semiconductor material constituting a semiconductor region that exhibits an optical-electrical conversion effect is used as a laser medium with a laser wavelength of 500 nm or less.

[0082] (5) In any one of the optical power supply systems (1) to (4) above, The light receiving section is a photoelectric conversion element in which a semiconductor material constituting a semiconductor region that exhibits a light-to-electricity conversion effect is used as a laser medium with a laser wavelength of 500 nm or less.

[0083] (6) A power supply device that supplies power to a power receiving device by spatial transmission of power supply light, a light emitting unit that outputs the power supply light; and an adjusting unit that variably adjusts the beam diameter of the power supply light, The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light, and stops the reduction based on a response obtained in response to the beam diameter of the power supply light.

[0084] (7) In the power supply device of (6) above, The light emitting section is a semiconductor laser in which a semiconductor material constituting a semiconductor region that exhibits an optical-electrical conversion effect is used as a laser medium with a laser wavelength of 500 nm or less.

[0085] (8) A power receiving device that receives power through spatial transmission of power supply light from a power supply device, a light receiving unit that converts the received power supply light into electric power; and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; When the beam diameter of the power supply light from the start of output is gradually reduced by the power supply device, the response unit responds to the power supply device in accordance with the beam diameter of the power supply light.

[0086] (9) In the power receiving device of (6) above, The responding unit makes the response in accordance with the electric power obtained by converting the power supply light by the light receiving unit.

[0087] (10) In the power receiving device of (8) or (9) above, The light receiving section is a photoelectric conversion element in which a semiconductor material constituting a semiconductor region that exhibits a light-to-electricity conversion effect is used as a laser medium with a laser wavelength of 500 nm or less. [Explanation of symbols]

[0088] 1,1A~1E Optical power supply system 100 First data communication device 110, 110B, 110C Power supply device 111 Power supply semiconductor laser (light emitting part) 112 Power supply light 112B,112C,112D signal light 120 Transmission Department 125 Signal Light 130 Receiving unit 131 Signal photodiode 150B,150C,150E Adjustment section 151B Optical Elements 152B, 152C, 152E control device 153B, 153C Response receiving unit 200 fiber optic cable 250 optical fiber 300 Second data communication device 310, 310B, 310C Power receiving device 311 Photoelectric conversion element 311a Photosensitive surface 320 Transmission Department 321 Signal Semiconductor Laser 322 Modulator 323 Laser Light 325 Signal Light 330 Receiving unit 340 Data Processing Unit 350B, 350C Response section 351B Signal Semiconductor Laser 351C Reflector 351D Reflector (Response Unit) 352B, 352C control device h Foreign matter s beam diameter

Claims

1. An optical power supply system that supplies power from a power supply device to a power receiving device by spatial transmission of power supply light, the power supply device includes a light emitting unit that outputs the power supply light and an adjusting unit that variably adjusts a beam diameter of the power supply light, the power receiving device includes a light receiving unit that converts the received power supply light into electric power, and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light and stops the reduction based on the response, The response unit performs the response based on the output of the light receiving unit.

2. An optical power supply system that supplies power from a power supply device to a power receiving device by spatial transmission of power supply light, the power supply device includes a light emitting unit that outputs the power supply light and an adjusting unit that variably adjusts a beam diameter of the power supply light, the power receiving device includes a light receiving unit that converts the received power supply light into electric power, and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light and stops the reduction based on the response, The light-emitting unit is an optical power supply system in which a semiconductor material constituting a semiconductor region that exhibits an optical-electrical conversion effect is a semiconductor laser that uses a laser medium with a laser wavelength of 500 nm or less.

3. An optical power supply system that supplies power from a power supply device to a power receiving device by spatial transmission of power supply light, the power supply device includes a light emitting unit that outputs the power supply light and an adjusting unit that variably adjusts a beam diameter of the power supply light, the power receiving device includes a light receiving unit that converts the received power supply light into electric power, and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light and stops the reduction based on the response, The light receiving section is an optical power supply system in which a semiconductor material constituting a semiconductor region that exhibits an optical-electrical conversion effect is a photoelectric conversion element that serves as a laser medium with a laser wavelength of 500 nm or less.

4. a notification unit that notifies the power supply device of an abnormality in the receiving state of the power supply light at the light receiving unit, The optical power supply system according to claim 1 , wherein the power supply device stops outputting the power supply light in response to the notification.

5. A power supply device that supplies power to a power receiving device by spatial transmission of power supply light, a light emitting unit that outputs the power supply light; and an adjusting unit that variably adjusts the beam diameter of the power supply light, The adjusting unit gradually reduces the beam diameter from the start of output of the power supply light, and stops the reduction based on a response obtained in response to the beam diameter of the power supply light; The light-emitting section is a semiconductor laser in which a semiconductor material constituting a semiconductor region that produces an optical-electrical conversion effect is used as a laser medium with a laser wavelength of 500 nm or less.

6. A power receiving device that receives power by spatial transmission of power supply light from a power supply device that outputs power supply light while gradually reducing the beam diameter of the power supply light from the start of output, a light receiving unit that converts the received power supply light into electric power; and a response unit that responds to the power supply device depending on whether the beam diameter of the power supply light is appropriate; The power receiving device wherein the response unit transmits a response to the power supply device indicating that the beam diameter of the power supply light is appropriate based on the electric power converted from the power supply light by the light receiving unit.

7. 7. The power receiving device according to claim 6, wherein the light receiving section is a photoelectric conversion element in which a semiconductor material constituting a semiconductor region that exhibits a light-to-electricity conversion effect is used as a laser medium with a laser wavelength of 500 nm or less.

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