Laser emitting device, laser emitting method, and laser wireless charging system

Abstract

A laser emission device (41), a laser emission method, and a laser wireless charging system are disclosed. The laser emission device (41) includes a detection and control module (414, 415), a pump source (411), a first group of reflecting mirrors (413), a gain medium (412), and a beam deflection module (416) arranged on an optical path. The gain medium (412) is pumped by the pump source (411) to emit fluorescence, and is excited by the resonance of the fluorescence between the first group of reflecting mirrors (413) and a laser receiving device (42) to emit laser light. The beam deflection module (416) deflects the fluorescence or laser light emitted by the gain medium (412) and reflects the fluorescence or laser light reflected by the laser receiving device (42) back into the gain medium (412). The detection and control module (414, 415) adjusts the beam deflection module (416) to a plurality of preset emission angles, detects the light intensity of the fluorescent or laser light at the plurality of preset emission angles and the light spot position of the laser light on the detection and control module (414, 415), and if the light intensity is greater than a first threshold at any of the preset emission angles, adjusts the emission angle of the beam deflection module (416) based on the light spot position, thereby expanding the range in which the laser emitting device tracks the laser receiving device (42) in the wireless charging field.

Description

[Technical field]

[0001] This application claims priority to Chinese Patent Application No. 202011204598.8, entitled "Laser Emission Apparatus, Laser Emission Method and Laser Wireless Charging System," filed with the State Intellectual Property Office of China on November 2, 2020, the entire contents of which are incorporated herein by reference.

[0002] Technical Field The present application relates to the field of laser wireless charging, and in particular to a laser emitting device, a laser emitting method, and a laser wireless charging system. [Background technology]

[0003] Laser wireless charging technology is a long-distance wireless charging technology. Specifically, a laser emitting device emits laser light to a laser receiving device, and after receiving the laser light, the laser receiving device converts the laser light into electrical energy for charging.

[0004] In practical applications, the laser receiver moves relative to the laser emitter, so the laser emitter needs to scan and track the position of the laser receiver. For a laser wireless charging system in which the laser emitter and the laser receiver transmit the laser light by forming resonance, the range in which the laser emitter emits the laser light is very small due to the stability limit of the resonance. As a result, it is highly likely that the laser receiver cannot receive the laser light. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE DISCLOSURE The embodiments of the present application provide a laser emitting device, a laser emitting method, and a laser wireless charging system for extending the range in which a laser emitting device tracks a laser receiving device. [Means for solving the problem]

[0006] In order to achieve the aforementioned objectives, the following technical solutions are used in the embodiments of this application.

[0007] According to a first aspect, a laser emission device is provided, including a detection and control module, a pump source, a first group of reflectors arranged on an optical path, a gain medium, and a beam deflection module. The gain medium is pumped by the pump source to emit fluorescence, and is excited by resonance of the fluorescence between the first group of reflectors and a laser receiving device to emit laser light. The beam deflection module is configured to emit the fluorescence or laser light emitted by the gain medium, and emit the fluorescence or laser light reflected by the laser receiving device into the gain medium. The detection and control module is configured to: sequentially adjust the beam deflection module to multiple preset emission angles, i.e., scan the laser receiving device by emitting the laser light in a specific area; detect the light intensity of the fluorescence or laser light at multiple preset emission angles and the light spot position of the laser light on the detection module; and adjust the emission angle of the beam deflection module based on the light spot position when the light intensity is greater than a first threshold at any preset emission angle, i.e., when the laser light generates resonance between the first reflecting mirror group and the laser receiving device, so that the laser light emitted by the beam deflection module is directed to the laser receiving device, i.e., fine adjustment is performed. According to the laser emitting device provided in this embodiment of the present application, the beam deflection module can adjust the emission angle of the laser light at a large angle and does not need to be limited by the reflection range of the reflecting mirror and the stability of the resonant cavity. Therefore, the emission range of the laser light of the laser emitting device can be expanded.

[0008] In one possible implementation, the detection and control module includes a control module and a detection module, and the control module is configured to adjust the emission angle of the beam deflection module in a direction that reduces the deviation between the light spot position and the center of the detection module until the absolute value of the deviation between the light spot position and the center of the detection module is equal to or less than a second threshold. This implementation discloses how the control module specifically controls the emission angle of the beam deflection module in a finer manner. The closer the light spot position is to the center of the detection module, the higher the power of the laser light is.

[0009] In a preferred implementation, the beam deflection module includes a first galvanometer scanner and a second galvanometer scanner, the fluorescence or laser light from the gain medium is reflected by the first galvanometer scanner and the second galvanometer scanner in sequence and then emitted, and the fluorescence or laser light emitted from the laser emitter is reflected by the second galvanometer scanner and the first galvanometer scanner in sequence and then returned to the gain medium; the control module adjusts the emission angle of the beam deflection module by controlling the rotation angle of the first galvanometer scanner and the second galvanometer scanner. This implementation discloses a possible structure of the beam deflection module. The scanning angle may be adjusted by adjusting the rotation angle of the first galvanometer scanner and the second galvanometer scanner, or the direction of the laser light emitted by the laser emitter may be fine-tuned to be directed to the laser receiver.

[0010] In one possible implementation, the laser emitting device further includes a first lens group, the first lens group is disposed on an optical path between the gain medium and the beam deflection module, and the first lens group is configured to adjust the working distance and the field of view of the stable region of the laser light. The stability of the resonant cavity at different distances and different angular ranges can be changed by changing the optical parameters of the first lens group, such as the focal length or zoom-in ratio of the lens. For example, a smaller zoom-in ratio indicates a shorter working distance of the stable zone, but a larger field of view of the stable zone. A larger zoom-in ratio indicates a longer working distance of the stable zone, but a smaller field of view of the stable zone. In another example, a longer focal length indicates a longer working distance of the stable zone, but a smaller field of view of the stable zone. A shorter focal length indicates a shorter working distance of the stable zone, but a larger field of view of the stable zone.

[0011] In one possible implementation, the laser emitting device further includes a partial reflector, the partial reflector is disposed on the optical path between the gain medium and the beam deflection module, and the partial reflector can partially reflect the fluorescence or laser light to the gain medium. The partial reflector can partially reflect the fluorescence or laser light of the first wavelength to the gain medium, thereby reducing the pumping power threshold of the resonant cavity of the laser light of the first wavelength. The optical intensity of the fluorescence reflected by the partial reflector is weak, and the reflectivity of the partial reflector multiplied by the gain coefficient of the gain medium is less than 1, so that no resonance is formed between the partial reflector and the first reflector in the absence of reflection by the laser receiving device. When the laser receiving device reflects the light of the first wavelength, the gain in the resonant cavity is greater than the loss, and a resonance may be generated in the resonant cavity, and the laser light of the first wavelength may be emitted.

[0012] In one possible implementation, the pump source and the gain medium are located together as an electrically pumped semiconductor gain chip, which can reduce the volume of the laser emitting device.

[0013] According to a second aspect, there is provided a laser emission method applied to a laser emission device according to any of the first aspect and the implementation of the first aspect, the method including: sequentially adjusting a beam deflection module of the laser emission device to a plurality of preset emission angles; detecting the light intensity of the fluorescent light or laser light at the plurality of preset emission angles and the light spot position of the laser light in a detection and control module of the laser emission device; and adjusting the emission angle of the beam deflection module based on the light spot position, so that the laser light emitted by the beam deflection module is directed to a laser receiving device if the light intensity is greater than a first threshold at any preset emission angle.

[0014] In one possible implementation, the step of adjusting the emission angle of the beam deflection module based on the light spot position includes: adjusting the emission angle of the beam deflection module in a direction that reduces the deviation between the light spot position and the center of the detection module of the detection control module until the absolute value of the deviation between the light spot position and the center of the detection module is less than or equal to a second threshold.

[0015] According to a third aspect, a laser wireless charging system is provided, the laser wireless charging system including a laser emitting device and a laser receiving device according to any of the first aspect and the implementation of the first aspect. The laser receiving device includes a second reflector group, a laser photovoltaic cell, a power conversion circuit, and a load circuit. The second reflector group is configured to reflect a portion of the fluorescent light or laser light from the beam deflection module of the laser emitting device back to the beam deflection module and transmit another portion to the laser photovoltaic cell; the power conversion circuit is configured to perform power conversion on the electric energy from the laser photovoltaic cell and output the electric energy to the load circuit.

[0016] For the technical effects of the second and third aspects, please refer to the technical effects of the first aspect and any of the implementations of the first aspect, and the details will not be repeated here. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram of the architecture of a laser wireless charging system according to an embodiment of the present application.

[0018] [Diagram 2] FIG. 1 is a schematic diagram of a laser principle according to an embodiment of the present application.

[0019] [Diagram 3] 1 is a schematic diagram of a reflector group structure according to an embodiment of the present application;

[0020] [Figure 4] FIG. 2 is a schematic diagram of the architecture of a laser wireless charging system according to an embodiment of the present application.

[0021] [Diagram 5] FIG. 1 is a schematic diagram of a fluorescence range and a viewing range according to an embodiment of the present application.

[0022] [Figure 6] 3 is a schematic diagram of the architecture of a laser wireless charging system according to an embodiment of the present application.

[0023] [Figure 7] FIG. 4 is a schematic diagram of the architecture of a laser wireless charging system according to an embodiment of the present application.

[0024] [Figure 8] 5 is a schematic diagram of the architecture of a laser wireless charging system according to an embodiment of the present application.

[0025] [Figure 9] 1 is a schematic diagram of a structure of a laser emitting device according to an embodiment of the present application;

[0026] [Figure 10] 2 is a schematic diagram of the structure of a laser emitting device according to an embodiment of the present application.

[0027] [Figure 11] 3 is a schematic diagram of a structure of a laser emitting device according to an embodiment of the present application.

[0028] [Figure 12] FIG. 2 is a schematic diagram of a structure of a four-quadrant photodetector according to an embodiment of the present application.

[0029] [Figure 13] FIG. 2 is a schematic diagram of controlling the rotation angles of a first galvanometer scanner and a second galvanometer scanner according to an embodiment of the present application.

[0030] [Figure 14] FIG. 2 is a schematic diagram of a scanning scheme according to an embodiment of the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Laser wireless energy transmission technology is a technology in which a laser emitter uses laser light as a carrier wave to transmit energy to the outside, and a laser receiver receives the laser light and converts it into electrical energy. Compared with electromagnetic wireless energy transmission technology, laser wireless energy transmission technology has better directivity and longer transmission distance.

[0032] Laser wireless energy transmission technology is applied to charge the laser receiving device, which is This is called laser wireless charging technology. As shown in Fig. 1, the laser wireless charging system includes a laser emitting device 11 and a laser receiving device 12. The laser receiving device 12 includes a laser photovoltaic cell 121, a power conversion circuit 122, and a load circuit 123. The laser emitting device 11 generates a laser light of a specific wavelength, the laser photovoltaic cell 121 converts the laser light energy into electrical energy after receiving the laser light, and the power conversion circuit 122 converts the voltage generated by the laser photovoltaic cell into a voltage required by the load circuit 123 to supply power to the load circuit 123.

[0033] The laser emitting device may be a device capable of emitting laser light, such as a laser wireless charger or a laser emitting tower. The laser receiving device may be a device capable of receiving laser light and converting the laser light into electrical energy, such as a mobile phone or an electric car.

[0034] Laser emitting devices are usually evolved from lasers, so we will first explain the basic operating principles of lasers.

[0035] As shown in Fig. 2, a laser includes a pump source 21, a gain medium (also called working material) 22, and a resonant cavity 23. The pump source 21 is used as an energy source and is configured to provide energy to the gain medium 22. The gain medium 22 is pumped to emit and amplify laser light of a specific wavelength. The laser light oscillates within the resonator 23, oscillating back and forth and building up within the gain medium 22. The laser light is then output from one end of the resonant cavity 23.

[0036] The pump source 21 includes an optical pump source, an electrical pump source, etc. A typical pump source is a semiconductor laser pump source that performs the conversion from electrical energy to optical energy.

[0037] Types of gain medium 22 include liquids, gases, and solids, where liquids include, for example, organic solutions, gases include, for example, carbon dioxide, and solids include, for example, semiconductors, crystalline materials (e.g., neodymium-doped yttrium aluminum garnet (Nd:YAG) crystals), and the like.

[0038] The resonant cavity 23 contains two mirror groups, and photons are reflected back and forth between the two mirror groups, continuously inducing stimulated emission in the gain medium, generating laser light with high optical intensity. The mirror groups are used to return the incident light along the original path or parallel to it. One mirror group in the resonant cavity is a total reflector, and the other mirror group is a partial reflector, so that a part of the laser light can be output from the other side of the partial reflector.

[0039] As shown in Fig. 3, the structure of the reflecting mirror group is not limited in the present application. The reflecting mirror group may be, for example, a corner reflector shown in Fig. 3A, a mirror group including a convex lens and a plane mirror shown in Fig. 3B, a mirror group including a convex lens and a concave mirror shown in Fig. 3C, a substantially spherical retroreflector with a refractive index of 1.9 to 2.1 shown in Fig. 3D, or the like.

[0040] The processes by which photons are emitted by the gain medium 22 include spontaneous emission and stimulated emission, so that the light emitted by the gain medium 22 also includes fluorescent and laser light.

[0041] After the gain medium 22 is pumped by the pump source 21, a population inversion of the upper energy levels occurs (i.e., the amount of atoms in the higher energy level E2 is greater than the amount of atoms in the lower energy level E1), and the particles in the inverted upper energy level can emit photons and return to the ground state. This process is spontaneous emission, and the light is fluorescence. If the resonant cavity 23 does not form a resonance, the spontaneous fluorescence is dominant, and the spontaneous fluorescence has a solid angle of 4π (i.e., non-directional emission in all directions).

[0042] After the resonant cavity starts to resonate, the gain medium 22 is stimulated by the fluorescence reflected in the resonant cavity, amplifies the light, and continues to emit the light in the original direction. This process is stimulated emission. The amplified light is laser light, and the emission direction of the amplified light is the same as the direction of the incident light. Therefore, the amplified light has good directionality. When the resonant cavity starts to resonate, the spontaneous emission is greatly weakened, the intensity of the fluorescence decreases, and the intensity of the laser light increases.

[0043] The laser including two reflector groups is used in the field of laser wireless charging. As shown in FIG. 4, an embodiment of the present application provides a laser wireless charging system including a laser emitting device 41 and a laser receiving device 42. The laser emitting device 41 includes a pump source 411, a gain medium 412, and a first reflector group 413. The laser receiving device 42 includes a laser photovoltaic cell 421, a power conversion circuit 422, a load circuit 423, and a second reflector group 424. The power conversion circuit 422 includes a direct current-direct current (DC-DC) circuit 4221, and optionally further includes a maximum power point tracking (MPPT) circuit 4222.

[0044] The operating principle of the laser wireless charging system is as follows.

[0045] The first reflecting mirror group 412 and the second reflecting mirror group 424 form a resonant cavity. The first reflecting mirror group 412 is a full reflecting mirror, and the second reflecting mirror group 424 is a partial reflecting mirror. The pump source 411 is used as an energy source to provide energy for the gain medium 412. The gain medium 412 is pumped to emit and amplify a laser light of a specific wavelength. The laser light oscillates and travels back and forth in the resonant cavity, and a part of the laser light is emitted from the other side of the second reflecting mirror group 412. After receiving the laser light, the laser photovoltaic cell 421 converts the laser light energy into electrical energy, and the power conversion circuit 422 converts the voltage generated by the laser photovoltaic cell into a voltage required by the load circuit 423 to supply power to the load circuit 423.

[0046] The MPPT circuit 4222 in the power conversion circuit 422 is configured to perform maximum power tracking so that the laser photovoltaic cell 421 outputs maximum power, and the MPPT 4222 is usually a boost circuit. The DC-DC circuit 4221 is configured to convert the voltage output by the MPPT circuit 4222 into a voltage required by the load circuit. The DC-DC circuit 4221 may be a circuit having a voltage conversion function such as a buck circuit, a boost circuit, or a buck-boost circuit.

[0047] The reflector can return the incident light along the original path or parallel within a certain range, so as long as the first reflector group, the second reflector group and the gain medium are approximately in a straight line, the energy transmission can be achieved, and the automatic positioning and tracking of the laser receiving device can be achieved within a certain range. If a person enters the optical path, the laser light will stop resonating in the resonant cavity, so no harm will be caused to the person.

[0048] However, due to the limited reflection range of the reflecting mirror and the limited stability of the resonant cavity, the scanning and tracking range is not large enough. As shown in FIG. 5, the gain medium 412 is pumped to emit fluorescence within a certain fluorescence range. Limited by the stability of the resonant cavity, the second reflecting mirror group 424 cannot form a resonant cavity with the first reflecting mirror group 413 within the entire fluorescence range, but instead can form a resonant cavity with the first reflecting mirror group 413 within a field of view range that is smaller than the fluorescence range. When the second reflecting mirror group 424 (i.e., the laser receiving device 42) moves within the field of view range, the laser light is received due to resonance. When the second reflecting mirror group 424 (i.e., the laser receiving device 42) moves outside the field of view range, the resonance stops and the laser light cannot be received.

[0049] Therefore, an embodiment of the present application provides another laser wireless charging system. A beam deflection module is added to the laser emitting device to expand the viewing range. The laser receiving device is scanned within the viewing range. The laser emitting device detects the light intensity of the fluorescent or laser light and the light spot position on the detection module. When the laser receiving device is within the viewing range, the laser emitting device and the laser receiving device form a resonant cavity, and the laser emitting device generates laser light. In this case, the light intensity of the laser light is stronger than the threshold value to implement coarse positioning. Then, the laser emitting device adjusts the beam deflection module according to the light spot position of the laser light on the detection module to adjust the laser power generated by the laser emitting device. The beam deflection module can adjust the emission angle of the laser light by a large angle, and the limitations of the reflection range of the reflector and the stability of the resonant cavity are eliminated. Therefore, the laser light emission range of the laser emitting device can be expanded, and the range in which the laser emitting device tracks the laser receiving device is expanded.

[0050] 6 to 8, based on the laser wireless charging system shown in FIG. 4, the laser emitting device 41 may include a detection and control module (including a control module 414 and a detection module 415), a pump source 411, a first reflecting mirror group 413, a gain medium 412, and a beam deflection module 416 sequentially arranged on the optical path of the resonant cavity. The control module 414 is electrically connected to the detection module 415, the pump source 411, and the beam deflection module 416.

[0051] Optionally, as shown in Figures 7 and 8, the laser emitting device 41 may further include a proportional beam splitter 417 disposed within the resonant cavity, which may be disposed on the optical path between the gain medium 412 and the beam deflection module 416 (Figure 7) or on the optical path between the first group of reflecting mirrors 413 and the gain medium 412 (Figure 8).

[0052] Optionally, as shown in Figures 6 to 8, the laser emitting device 41 may further include a first lens group 418, which may be disposed on the optical path between the gain medium 412 and the beam deflection module 416.

[0053] Optionally, as shown in Figures 6 to 8, the laser emitting device 41 may further include a partial reflector 419, which may be disposed on the optical path between the gain medium 412 and the beam deflection module 416.

[0054] The functions of all components are explained below.

[0055] The gain medium 412 is pumped by the pump source 411 to emit fluorescence of a first wavelength (e.g., 1064 nm) to the first reflecting mirror group 413 and the beam deflection module 416. After reflecting the fluorescence of the first wavelength from the gain medium 412 back to the gain medium, the first reflecting mirror group 413 may emit the fluorescence through the beam deflection module 416 and emit the fluorescence to the laser receiving device 42. After reflecting the fluorescence of the first wavelength emitted from the outside of the device (e.g., reflected from the laser receiving device 42) back to the gain medium 412, the beam deflection module 416 transmits the fluorescence to the first reflecting mirror group 413. When no resonance is formed between the laser receiving device 42 and the laser emitting device 41, the gain medium 412 emits fluorescence, and part of the fluorescence is reflected by the beam deflection module 416 to the outside of the laser emitting device 41, and the part of the fluorescence is very weak and safe for the human body.

[0056] The gain medium 412 is further excited by the resonance of the fluorescence between the first reflecting mirror group 413 and the laser receiving device 42 (second reflecting mirror group 424), and a laser beam is emitted. Similar to the fluorescence, after reflecting the first wavelength laser beam from the gain medium 412 back to the gain medium, the first reflecting mirror group 413 may emit the laser beam through the beam deflection module 416 and emit the laser beam to the laser receiving device 42. After reflecting the first wavelength laser beam emitted from outside the device (e.g., reflected from the laser receiving device 42) back to the gain medium 412, the beam deflection module 416 transmits the laser beam to the first reflecting mirror group 413.

[0057] Optionally, the pump source 411 and the gain medium 412 may be located separately, as shown in Figures 9 and 10. For example, the pump source 411 may be an optical pump source, which emits pump light of a second wavelength (e.g., 808 nm) to the gain medium 412. The gain medium 412 is excited by the pump light of the second wavelength to emit fluorescent or laser light of a first wavelength to the first mirror group 413 and the beam deflection module 416.

[0058] Optionally, the pump source 411 and the gain medium 412 may be collocated, as shown in Figure 11. For example, the pump source 411 and the gain medium 412 may be electrically pumped semiconductor gain chips.

[0059] Optionally, as shown in Figures 9-11, the first reflecting mirror group 413 may include a convex lens F1 and a plane mirror M1. A distance L1 between the convex lens F1 and the plane mirror M1 is approximately equal to a focal length f1 of the convex lens F1, and a distance L2 between the convex lens F1 and the gain medium is approximately equal to the focal length f1 of the convex lens F1.

[0060] Also, as shown in FIG. 9 and FIG. 10, a high transmission coating (e.g., an anti-reflective (AR) high transmission coating) for the second wavelength may be grown on both sides of the plane mirror M1, and a high reflection coating (e.g., a high-reflective (HR) low transmission coating) for the first wavelength may be grown on one side (the reflective surface) of the plane mirror M1. Also, high transmission coatings for the first and second wavelengths may be grown on both sides of the convex lens F1. In this way, the pump light of the second wavelength emitted by the pump source 411 can be irradiated to the gain medium 412 through the plane mirror M1 and the convex lens F1, and the fluorescent or laser light of the first wavelength emitted by the gain medium 412 is reflected back to the gain medium 412.

[0061] Optionally, as shown in Figures 9 and 10, a first side of the gain medium 412 may have high transmission coatings for the first and second wavelengths grown, and a second side of the gain medium 412 may have high transmission coatings for the first wavelength and high reflection coatings for the second wavelength grown. The first side of the gain medium 412 is the side facing the first group of reflecting mirrors 413, and the second side of the gain medium 412 is the opposite side to the first side. In this way, pump light of the second wavelength can enter the gain medium 412 from the first side without leaking from the second side, and fluorescent or laser light of the first wavelength can be emitted from the first side and the second side, or to the first side and the second side.

[0062] Optionally, as shown in Fig. 6, the first reflecting mirror group 413 is further configured to transmit a portion of the fluorescent or laser light of the first wavelength to the detection module 415. For example, as shown in Fig. 11, the flat mirror M1 may be a partially reflecting mirror. For example, the transmittance may be 5% and the reflectance may be 95%. A high transmittance film for the first wavelength may be grown on both sides of the convex lens F1 so that a portion of the fluorescent or laser light of the first wavelength can be transmitted to the detection module 415 through the flat mirror M1.

[0063] 11, a highly transparent film for the first wavelength may be grown on the entrance surface (also called the exit surface) of the gain medium 412, and a highly reflective film for the first wavelength may be grown on the reflective surface (the interface surface with the pump source 411) of the gain medium 412. This allows the fluorescence or laser light of the first wavelength to be emitted from the gain medium, or the fluorescence or laser light of the first wavelength to be emitted into the gain medium, and reduces loss of the fluorescence or laser light of the first wavelength in the gain medium.

[0064] The proportional beam splitter 417 is configured to transmit the portion (e.g., 4%) of the fluorescent or laser light of the first wavelength to the detection module 415, and the other portion (e.g., 96%) is reflected at a specific angle. The reflected portion resonates between the first reflecting mirror group 413 and the beam deflection module 416. For example, as shown in Fig. 9 and Fig. 10, the proportional beam splitter 417 may be a partial reflector at a non-perpendicular angle (e.g., 45 degrees) to the laser light and with a specific transmittance (e.g., 4%) or reflectance (e.g., 96%). When a resonance is formed between the laser emitting device and the laser receiving device, the proportional beam splitter 417 has a specific transmittance, so that a portion of the laser light of the first wavelength reflected from the laser receiving device 42 is transmitted through the proportional beam splitter 417 to the detection module 415.

[0065] The detection and control module is configured to: sequentially adjust the beam deflection module to multiple preset emission angles, i.e., scan the laser receiving device by emitting the laser light in a specific area; detect the light intensity of the fluorescence or laser light at multiple preset emission angles and the light spot position of the laser light on the detection and control module; and adjust the emission angle of the beam deflection module based on the light spot position when the light intensity is greater than a first threshold at any preset emission angle, i.e., when the laser light generates resonance between the first reflector group 413 and the second reflector group 424 of the laser receiving device, so that the laser light emitted by the beam deflection module is directed to the laser receiving device, i.e., fine adjustment is performed. The closer the light spot position is to the center of the detection and control module, the higher the power of the laser light is.

[0066] The detection module 415 is configured to detect the light intensity of the fluorescent light or laser light of the first wavelength and the light spot position of the laser light on the detection module 415. Due to the presence of a field of view, the light spot position of the laser light irradiated on the light receiving surface of the detection module 415 is not fixed. The detection module 415 may include, for example, a position sensitive device (PSD), an infrared camera, and a four-quadrant photoelectric detector or photodiode (PD).

[0067] Optionally, to avoid spurious light interference with the light spot position detection, a bandpass filter for a first wavelength, for example a bandpass filter of 1064 nm, may be placed on the surface of the detection module 415, or a bandpass coating film for the first wavelength is grown on the surface of the detection module 415. In this way, only light around the first wavelength can be detected by the detection module 415, and light of other wavelengths cannot be detected by the detection module 415.

[0068] 6 and 11, in one possible implementation, when the laser emitting device 41 does not include a proportional beam splitter 417, the detection module 415 may be disposed on the light transmitting side of the first reflecting mirror group 413. The first reflecting mirror group 413 may transmit a portion of the fluorescent light or laser light of the first wavelength to the detection module 415, which detects the light intensity and light spot position of the fluorescent light or laser light of the first wavelength.

[0069] In another possible implementation, as shown in Figures 7 to 10, when the laser emitting device 41 includes a proportional beam splitter 417, the proportional beam splitter 417 is configured to transmit a portion of the fluorescent light or laser light of the first wavelength to the detection module 415. The detection module 415 detects the light intensity of the fluorescent light or laser light of the first wavelength and the light spot position of the laser light on the detection module 415.

[0070] The detection principle of the detection module 415 is described below.

[0071] For example, a four-quadrant photoelectric detector is used as an example. As shown in FIG. 12, the four-quadrant photoelectric detector is a photoelectric detection device formed by arranging four PDs with the same performance based on the four quadrants (A, B, C, D) of a Cartesian coordinate system. When the surface of the four-quadrant photoelectric detector is irradiated with fluorescence or laser light, the PD in each quadrant generates a current, and the current signal is converted into a voltage signal for sampling through an external circuit. When the center of the four-quadrant photoelectric detector is irradiated with fluorescence or laser light, the PD output currents in the four quadrants are the same. The PD output current in quadrant A is Ia, the PD output current in quadrant B is Ib, the PD output current in quadrant C is Ic, and the PD output current in quadrant D is Id. The magnitude of the current corresponds to the light intensity of the fluorescence or laser light. The coordinates (δ) of the center of the light point are expressed as follows: X , δ Y ) is expressed by the following equations (1) and (2).

number

[0072] When Ia + Id = Ic + Ib, that is, when the sum of the currents on the left side of the X-axis is equal to the sum of the currents on the right side of the X-axis, the centroid of the light spot is located on the Y-axis, that is, the X-axis coordinate of the centroid of the light spot is represented by x = 0.

[0073] When Ia + Ib = Ic + Id, that is, when the sum of the currents above the Y-axis is equal to the sum of the currents below the Y-axis, the centroid of the light spot is located on the X-axis, that is, the Y-axis coordinate of the centroid of the light spot is represented by y = 0.

[0074] When Ia + Id > Ib + Ic, that is, when the sum of the currents on the right side of the X-axis is greater than the sum of the currents on the left side of the X-axis, the centroid of the light spot is located on the positive half-axis of the X-axis, that is, the X-axis coordinate of the centroid of the light spot is represented by x > 0.

[0075] When Ib + Ic > Ia + Id, that is, when the sum of the currents on the left side of the X-axis is greater than the sum of the currents on the right side of the X-axis, the centroid of the light spot is located on the negative half-axis of the X-axis, that is, the X-axis coordinate of the centroid of the light spot is represented by x < 0.

[0076] When Ia + Ib > Ic + Id, that is, when the sum of the currents above the Y-axis is greater than the sum of the currents below the Y-axis, the centroid of the light spot is located on the positive half-axis of the Y-axis, that is, the Y-axis coordinate of the centroid of the light spot is represented by y > 0.

[0077] When Ia + Ib < Ic + Id, that is, when the sum of the currents below the Y-axis is greater than the sum of the currents above the Y-axis, the centroid of the light spot is located on the negative half-axis of the Y-axis, that is, the Y-axis coordinate of the centroid of the light spot is represented by y < 0.

[0078] Based on the above method, the light intensity of fluorescence or laser light and the position of the light spot can be roughly obtained.

[0079] For example, the detection module 415 is used as an example of a PD. A four-quadrant photoelectric detector may be formed using multiple PDs. The principle of the four-quadrant photoelectric detector formed using multiple PDs is the same as that of the four-quadrant photoelectric detector. Details are not repeated here again.

[0080] For example, it is used as an example that the detection module 415 is an infrared camera. The infrared camera transmits the captured image to the control module 414, and the control module 414 may obtain the brightness and the light spot position of the fluorescent light or laser light of the first wavelength. The brightness may represent the light intensity. For example, the bright area in the image is the light spot position, and the corresponding light intensity may be obtained by extracting the brightness value of the light spot position.

[0081] For example, the detection module 415 is used as an example. The receiving surface of the PSD is approximately square, with a side length of L.

[0082] In one possible implementation, the PSD may output four signals: X1, X2, Y1, and Y2. X1 and X2 are voltage signals converted from the photocurrent generated by the light spot detection performed by two electrodes on the X-axis of the PSD. Y1 and Y2 are voltage signals converted from the photocurrent generated by the light spot detection performed by two electrodes on the Y-axis of the PSD.

[0083] In another possible implementation, the PSD may output three signals: XC, YC, and OUTH1, where XC, YC, and OUTH1 are related to X1, X2, Y1, and Y2 as XC=(X2+Y1)-(X1+Y2), YC=(X2+Y2)-(X1+Y1), and OUTH1=X1+X2+Y1+Y2.

[0084] The light spot position of the light spot in the X direction can be obtained by calculating XC / OUTH1×L / 2, and the light spot position of the light spot in the Y direction can be obtained by calculating YC / OUTH1×L / 2. The coordinate origin is the center of the light receiving surface of the PSD, and OUTH1 is the intensity of the light spot. Therefore, the detection module 415 may detect the intensity and the light spot position of the fluorescent light or laser light of the first wavelength.

[0085] Optionally, as shown in FIG. 9-FIG. 11, the beam deflection module 416 may include a first galvanometer scanner 4161 and a second galvanometer scanner 4162. Optionally, a high-reflectivity film (e.g., a high-reflective (HR) low-transmittance film) for the first wavelength may be grown on the surface of the first galvanometer scanner 4161 and the second galvanometer scanner 4162. The fluorescence or laser light of the first wavelength from the gain medium 412 is reflected by the first galvanometer scanner 4161 and the second galvanometer scanner 4162 in sequence and then emitted, and the fluorescence or laser light of the first wavelength emitted from the laser emitter is reflected by the second galvanometer scanner 4162 and the first galvanometer scanner 4161 in sequence and transmitted back to the gain medium 412. The control module 414 adjusts the emission angle of the beam deflection module 416 by controlling the rotation angles of the first galvanometer scanner 4161 and the second galvanometer scanner 4162 .

[0086] As shown in Fig. 9, when the positions of the first galvano scanner 4161 and the second galvano scanner 4162 are fixed, an approximately cone-shaped fluorescence range is formed, and the field of view range is smaller than the fluorescence range. As shown in Fig. 13, the coordinates of the center of the fluorescence range projected onto a plane perpendicular to the motor rotation axis of the first galvano scanner 4161 are (x, y), d is the distance from the second galvano scanner 4162 to the plane, e is the distance between the centers of the first galvano scanner 4161 and the second galvano scanner 4162, and the rotation angle is f. Here, the rotation angle θx of the first galvano scanner 4161 around the X-axis satisfies Equation 3, and the rotation angle of the second galvano scanner 4162 around the Y-axis satisfies Equation 4:

number

[0087] Therefore, the emission angle of the beam deflection module 416 can be adjusted to control the scanning path by controlling the rotation angles of the first galvanometer scanner 4161 and the second galvanometer scanner 4162. For example, there are several possible scanning paths as shown in FIG. 14. The scanning path may be a step-by-step scan from the center to the periphery as shown in FIG. 14A, a step-by-step scan from the periphery to the center as shown in FIG. 14B, a step-by-step scan by rows as shown in FIG. 14C, a step-by-step scan by columns as shown in FIG. 14D, or a diagonal step-by-row scan as shown in FIG. 14E. This is not limited in the present application. It should be noted that in order to avoid the occurrence of dead zones, the scanning step should be controlled so that the scanning step is less than the width of the field of view.

[0088] The partial reflector 419 can partially reflect the fluorescent light or laser light of the first wavelength to the gain medium 412, thereby lowering the pumping power threshold of the resonant cavity of the laser light of the first wavelength. Since the light intensity of the fluorescent light reflected by the partial reflector 419 is weak and the reflectivity of the partial reflector 419 multiplied by the gain coefficient of the gain medium 412 is less than 1, no resonance is formed between the partial reflector 419 and the first reflector 415 in the absence of reflection by the laser receiving device 42. When the laser receiving device 42 reflects the light of the first wavelength, the gain in the resonant cavity is greater than the loss, and a resonance may be generated in the resonant cavity, and the laser light of the first wavelength may be emitted.

[0089] The first lens group 418 can adjust the field of view of the laser light of the first wavelength, the field of view includes the working distance and the field of view of the stable zone. The stability of the resonant cavity at different distances and different angle ranges can be changed by changing the optical parameters of the first lens group 418, for example, the focal length or zoom-in ratio of the lens. For example, a smaller zoom-in ratio indicates a shorter working distance of the stable zone, but a larger field of view of the stable zone. A larger zoom-in ratio indicates a longer working distance of the stable zone, but a smaller field of view of the stable zone. In another example, a longer focal length indicates a longer working distance of the stable zone, but a smaller field of view of the stable zone. A shorter focal length indicates a shorter working distance of the stable zone, but a larger field of view of the stable zone.

[0090] 10, the first lens group 418 may include a convex lens F2 and a convex lens F3. The positional relationship between the partial reflecting mirror 419 and each lens in the first lens group is not limited in the present application. For example, the partial reflecting mirror 419 may be disposed between the convex lens F2 and the convex lens F3, or may be disposed outside the first lens group on the side closer to the convex lens F2, or may be disposed outside the first lens group on the side closer to the convex lens F3.

[0091] Optionally, the first focus of the convex lens F2 may be located on the gain medium 412 (e.g., may be located at the center of the gain medium 412). Note that if the laser emitting device 41 includes a proportional beam splitter 417, the first focus of the convex lens F2 may be located on the gain medium 412 after being reflected by the proportional beam splitter 417. The second focus of the convex lens F2 may coincide with the first focus of the convex lens F3, which may be located on a reflective surface of the beam deflection module 416 (e.g., a reflective surface of the first galvanometer scanner 4161).

[0092] The operating principle of the laser emission device 41 is as follows.

[0093] The control module 414 controls the pump source 411 as a first pump intensity, and sequentially adjusts the beam deflection module 416 to multiple preset emission angles to scan the target area. At this time, the laser emitter 41 emits fluorescence, and this process is a rough positioning process. Since the laser emitter 41 has a certain viewing range, when the laser receiver 42 is outside the viewing range, no resonance is formed in the resonant cavity, and there is no obvious light spot on the detection module 415.

[0094] If the control module 415 detects through the detection module 415 that the intensity of the fluorescence or laser light of the first wavelength is greater than the first threshold at the any preset emission angle, it is considered that the laser receiving device 42 is within the field of view of the laser emitting device 41, and a resonance is formed between the laser emitting device 41 and the laser receiving device 42. In this case, the laser emitting device 41 emits a laser light, and the coarse positioning process is completed. In this case, the light point may be located at the edge position of the detection module 415. The laser emitting device 41 also transmits energy to the laser receiving device 42 through the laser light, but the laser power is low.

[0095] The control module 414 controls the pump source 411 as the second pump intensity and adjusts the emission angle of the beam deflection module 416 based on the light spot position of the laser light of the first wavelength. Specifically, the control module 414 adjusts the emission angle of the beam deflection module 416 in a direction in which the deviation between the light spot position and the center of the detection module 415 becomes smaller until the absolute value of the deviation between the light spot position and the center of the detection module 415 becomes equal to or smaller than a second threshold. For example, the second threshold may be 100 micrometers.

[0096] If the light spot position is deviated from the center of the detection module 415, the detection module 415 sends the deviation to the control module 414, and the control module 414 adjusts the beam deflection module 416 so that the deviation is eliminated. That is, the control module 414 adjusts the beam deflection module 416 so that the optical axis of the laser emitting device 41 faces the laser receiving device 42. In this case, the light spot position is located at the center position of the detection module 415, and in this case, the laser emitting device 41 transmits energy to the laser receiving device 42 through the laser light, and the laser power is the highest.

[0097] Optionally, after the beam deflection module 416 is adjusted to the target emission angle, if the control module 415 detects that the light intensity of the first wavelength of the fluorescent light or the laser light is less than a second threshold, the control module 414 controls the pump source 411 as a first pump intensity and adjusts the beam deflection module 416 to multiple emission angles sequentially, i.e., the laser emitting device 41 loses track of the laser receiving device 42, and the coarse positioning is performed again. The second threshold is less than or equal to the first threshold.

[0098] Whether the light spot position is located at the center position of the detection module 415 can be determined in the following manner of the detection module 415.

[0099] If the detection module 415 is a four-quadrant photodetector or PD, the currents of the PD in the four quadrants are the same, ie, Ia=Ib=Ic=Id.

[0100] If the detection module 415 is an infrared camera, the bright area is located in the center of the image.

[0101] If the detection module 415 is a PSD, XC / OUTH1×L / 2 and YC / OUTH1×L / 2 are equal to the coordinates of the coordinate origin.

[0102] The second pump intensity and the first pump intensity can be the same or different. In one possible implementation, the first pump intensity is smaller than the second pump intensity, i.e., in the scanning process, the scanning is performed by using a smaller pump intensity to reduce the power consumption in the coarse positioning process. The laser emitting device 41 transmits energy to the laser receiving device 42 through the laser light, and transmits the energy with a large power to improve the transmission efficiency. Alternatively, the second pump intensity is adjusted based on the required power fed back by the laser receiving device 42.

[0103] The present application provides a laser emission device, a laser emission method, and a laser wireless charging system. The laser emission device includes a control module, a detection module, a pump source, a first reflecting mirror group arranged in a resonant cavity, a gain medium, and a beam deflection module. The control module is electrically connected to the detection module, the pump source, and the beam deflection module. The gain medium is pumped by the pump source to emit fluorescence, and is excited by the resonance of the fluorescence between the first reflecting mirror group and the laser receiving device to emit laser light. The beam deflection module emits the fluorescence or laser light emitted by the gain medium, and emits the fluorescence or laser light reflected by the laser receiving device into the gain medium. The control module is configured to adjust the beam deflection module to a plurality of preset emission angles, and the detection module is configured to detect the light intensity of the fluorescence or laser light and the light spot position of the laser light on the detection module, and if the light intensity is greater than a first threshold at any preset emission angle, the control module is further configured to adjust the emission angle of the beam deflection module based on the light spot position. The beam deflection module can adjust the laser light emission angle by a large angle and does not need to be limited by the reflection range of the reflecting mirror and the stability of the resonant cavity, so the laser light emission range of the laser emission device can be increased.

[0104] Those skilled in the art may recognize that the units and algorithm steps described with reference to the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered to go beyond the scope of this application.

[0105] Those skilled in the art can clearly understand that for the sake of convenience, the detailed operation processes of the above-mentioned systems, devices and units may be referred to the corresponding processes in the above-mentioned method embodiments, and the details will not be described again here.

[0106] In some embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other ways. For example, the device embodiments described are merely examples. For example, the division into units is merely a logical division of functions, and may be other divisions in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not implemented. In addition, the shown or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces. Indirect couplings or communication connections between devices or units may be implemented electronically, mechanically, or in other ways.

[0107] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, and may be located in one location or distributed over multiple network units. Some or all of those units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0108] In addition, the functional units in the embodiments of the present application may be integrated into one processing unit, each of the units may exist physically alone, or two or more units may be integrated into one unit.

[0109] The above description is merely a specific implementation of the present application, and is not intended to limit the scope of protection of the present application. Any variations or replacements that are easily conceived by those skilled in the art within the technical scope disclosed in this application shall fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims.

Claims

1. A laser emission device for a laser wireless charging system, the device having: a detection and control module, a pump source, a first reflector group disposed on an optical path, a gain medium, and a beam deflection module; the gain medium is pumped by the pump source to emit fluorescence and excited by resonance of the fluorescence between the first mirror group and a laser receiver to emit laser light; the beam deflection module is configured to emit the fluorescent light or the laser light emitted by the gain medium and emit the fluorescent light or the laser light reflected by the laser receiver into the gain medium; The detection and control module: Sequentially adjusting the beam deflection module to a plurality of preset emission angles; Detecting the light intensity of the fluorescent light or the laser light at the plurality of preset emission angles and a light spot position of the laser light at the detection and control module; and adjusting the emission angle of the beam deflection module based on the light spot position, so that the laser light emitted by the beam deflection module is directed toward the laser receiving device when the light intensity is greater than a first threshold at any preset emission angle. Laser emitting device.

2. the detection and control module includes a control module and a detection module; The control module is configured to adjust the emission angle of the beam deflection module in a direction that reduces the deviation between the light spot position and the center of the detection module until the absolute value of the deviation between the light spot position and the center of the detection module is less than or equal to a second threshold.

2. The laser emitting device of claim 1.

3. 3. The laser emitting device of claim 1, wherein the detection and control module comprises a control module, and the beam deflection module comprises a first galvanometer scanner and a second galvanometer scanner, the fluorescence or the laser light from the gain medium is sequentially reflected by the first galvanometer scanner and the second galvanometer scanner and then emitted, and the fluorescence or the laser light emitted from the laser emitting device is sequentially reflected by the second galvanometer scanner and the first galvanometer scanner and then transmitted back to the gain medium; and the control module adjusts the emission angle of the beam deflection module by controlling the rotation angles of the first galvanometer scanner and the second galvanometer scanner.

4. 4. The laser emitting device according to claim 1, wherein the detection and control module comprises a detection module, and the laser emitting device further comprises a proportional beam splitter arranged in the optical path, the proportional beam splitter configured to transmit a portion of the fluorescence or the laser light to the detection module, and the detection module configured to detect a light intensity and a light spot position of the portion of the fluorescence or the laser light.

5. 5. The laser emitting apparatus of claim 4, wherein the proportional beam splitter is disposed in the optical path between the gain medium and the beam deflection module.

6. 5. The laser emitting device of claim 4, wherein the proportional beam splitter is disposed in the optical path between the first group of mirrors and the gain medium.

7. 4. The laser emitter according to claim 1, wherein the detection and control module comprises a detection module, and the first reflecting mirror group is further configured to transmit a portion of the fluorescence or the laser light to the detection module, and the detection module is configured to detect a light intensity and a light spot position of the fluorescence or the laser light.

8. 8. The laser emitting device according to claim 1, further comprising a first lens group arranged in the optical path between the gain medium and the beam deflection module, the first lens group being configured to adjust a working distance and a field of view of a stable region of the laser light.

9. 9. The laser emitting device according to claim 1, further comprising a partial reflecting mirror, the partial reflecting mirror being arranged in the optical path between the gain medium and the beam deflection module, the partial reflecting mirror being capable of partially reflecting the fluorescence or the laser light to the gain medium.

10. 10. A laser emitting device according to claim 1, wherein the pump source and the gain medium are arranged together as an electrically pumped semiconductor gain chip.

11. 11. The laser emitting device according to claim 1, wherein the detection and control module comprises a detection module, the detection module comprising a position sensitive device PSD, an infrared camera and a four-quadrant photodetector or photodiode.

12. 12. The laser emitter according to claim 1, wherein the first reflecting mirror group is a corner reflector, a mirror group having a convex lens and a plane mirror, a mirror group having a convex lens and a concave mirror, or a substantially spherical retroreflector having a refractive index of 1.9 to 2.

1.

13. A laser emission method for application to a laser emission device according to any one of claims 1 to 12, comprising: Sequentially adjusting a beam deflection module of the laser emission device to a plurality of preset emission angles; detecting the light intensity of the fluorescent light or the laser light at the plurality of preset emission angles and the light spot position of the laser light at the detection and control module of the laser emission device; and adjusting an emission angle of the beam deflection module based on the light spot position, so that the laser light emitted by the beam deflection module is directed toward the laser receiving device when the light intensity is greater than a first threshold at any preset emission angle. method.

14. The step of adjusting the emission angle of the beam deflection module based on the light spot position includes: adjusting the emission angle of the beam deflection module in a direction that reduces the deviation between the light spot position and the center of the detection module of the detection and control module until the absolute value of the deviation between the light spot position and the center of the detection module of the detection and control module is equal to or less than a second threshold value; The method of claim 13.

15. 13. A laser wireless charging system having a laser emitting device and the laser receiving device described in any one of claims 1 to 12, wherein the laser receiving device has a second reflecting mirror group, a laser photovoltaic cell, a power conversion circuit, and a load circuit, the second reflecting mirror group being configured to reflect a portion of the fluorescent light or laser light from the beam deflection module of the laser emitting device back to the beam deflection module and transmit another portion to the laser photovoltaic cell; and the power conversion circuit being configured to perform power conversion on the electrical energy from the laser photovoltaic cell and output the electrical energy to the load circuit.

Images