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

Abstract

The present application discloses a laser emitting device, a laser emitting method and a laser wireless charging system, which relate to the field of wireless charging and are used to expand the range of the laser emitting device tracking the laser receiving device. The laser emitting device comprises: a detection control module, a pump source, a first reflector group arranged on the optical path, a gain medium and a beam deflection module; the gain medium is pumped by the pump source to emit fluorescence, and stimulated by the fluorescence to resonate between the first reflector group and the laser receiving device to emit laser; the beam deflection module emits the fluorescence or laser emitted by the gain medium and injects the fluorescence or laser reflected by the laser receiving device into the gain medium; the detection control module adjusts the beam deflection module to multiple preset emission angles; detects the light intensity of the fluorescence or laser at multiple preset emission angles and the spot position of the laser on the detection control module; if the light intensity at any preset emission angle is greater than the first threshold, the emission angle of the beam deflection module is adjusted according to the spot position.

Description

Technical Field

[0001] 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 Art

[0002] Laser wireless charging technology is a long-distance wireless charging technology, that is, a laser emitting device emits laser to a laser receiving device, and the laser receiving device receives the laser and converts it into electrical energy for charging.

[0003] In practical applications, since the laser receiving device is mobile relative to the laser emitting device, the laser emitting device needs to scan and track the position of the laser receiving device. For a laser wireless charging system in which the laser emitting device and the laser receiving device transmit laser light by forming resonance, the range of the laser emitted by the laser emitting device is very small due to the stability limitation of the resonance, making it easy for the laser receiving device to fail to receive the laser light. Summary of the invention

[0004] The embodiments of the present application provide a laser emitting device, a laser emitting method and a laser wireless charging system, which are used to expand the range in which the laser emitting device tracks the laser receiving device.

[0005] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0006] In the first aspect, a laser emitting device is provided, comprising: a detection control module, a pump source, and a first reflector group, a gain medium and a beam deflection module arranged on an optical path; the gain medium is used to emit fluorescence under the pumping of the pump source, and to emit laser under the resonance of the fluorescence between the first reflector group and the laser receiving device; the beam deflection module is used to emit the fluorescence or laser emitted by the gain medium, and to inject the fluorescence or laser reflected by the laser receiving device into the gain medium. The detection control module is used to: sequentially adjust the beam deflection module to multiple preset emission angles, that is, to scan the laser receiving device by emitting laser in a certain area. Detect the light intensity of the fluorescence or laser at multiple preset emission angles, and the spot position of the laser on the detection module; if the light intensity at any preset emission angle is greater than the first threshold, that is, the laser resonates between the first reflector group and the laser receiving device, then adjust the emission angle of the beam deflection module according to the spot position, so that the laser emitted by the beam deflection module is aligned with the laser receiving device, that is, fine adjustment is performed. The laser emitting device provided in the embodiment of the present application can improve the emission range of the laser of the laser emitting device because the beam deflection module can adjust the emission angle of the laser at a large angle and is not subject to the reflection range limitation of the reflector and the stability limitation of the resonant cavity.

[0007] In a possible implementation, the detection control module includes a control module and a detection module, and the control module adjusts the emission angle of the beam deflection module in a direction of reducing 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. This implementation discloses how the control module specifically finely controls the emission angle of the beam deflection module, and the closer the light spot position is to the center of the detection module, the greater the power of the laser.

[0008] In a possible implementation, the beam deflection module includes a first galvanometer and a second galvanometer; the fluorescence or laser from the gain medium is reflected by the first galvanometer and the second galvanometer in turn and then emitted, and the fluorescence or laser emitted from the outside of the laser emitting device is reflected by the second galvanometer and the first galvanometer in turn and then transmitted back 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 and the second galvanometer. This implementation discloses a possible structure of the beam deflection module, and the scanning angle can be adjusted by adjusting the rotation angle of the first galvanometer and the second galvanometer, and the direction of the laser emitted by the laser emitting device can also be finely adjusted to align with the laser receiving device.

[0009] In a possible implementation, the laser emitting device further includes a first lens group, which is disposed on the optical path between the gain medium and the beam deflection module, and is used to adjust the starting distance and starting angle range of the laser. By changing the optical parameters of the first lens group, such as the focal length or magnification of the lens, the stability of the resonant cavity at different distances and angle ranges can be changed. For example, the smaller the magnification, the closer the starting distance, but the larger the starting angle range; the larger the magnification, the longer the starting distance, but the smaller the starting angle range. For another example, the longer the focal length, the longer the starting distance, but the smaller the starting angle range; the shorter the focal length, the shorter the starting distance, but the larger the starting angle range.

[0010] In a possible embodiment, the laser emitting device further includes a partial reflector, which is disposed on the optical path between the gain medium and the beam deflection module, and the partial reflector can partially reflect fluorescence or laser light toward the gain medium. The partial reflector can partially reflect fluorescence or laser light of the first wavelength toward the gain medium, thereby reducing the starting pumping threshold of the laser light of the first wavelength. The fluorescence light intensity reflected by the partial reflector is relatively weak, and the reflectivity of the partial reflector multiplied by the gain coefficient of the gain medium is less than 1, so that when there is no reflection from the laser receiving device, no resonance is formed between the partial reflector and the first reflector. When the laser receiving device reflects light of the first wavelength, the gain in the resonant cavity is greater than the loss, and resonance can be generated in the resonant cavity and the laser light of the first wavelength is emitted.

[0011] In a possible implementation, the pump source and the gain medium are combined into an electrically pumped semiconductor gain chip, which can reduce the volume of the laser emitting device.

[0012] In a second aspect, a laser emission method is provided, which is applied to a laser emission device such as the first aspect and any embodiment thereof, the method comprising: adjusting a beam deflection module of the laser emission device to a plurality of preset emission angles in sequence; detecting the light intensity of the fluorescence or laser at a plurality of preset emission angles, and the spot position of the laser on a detection control module of the laser emission device; if the light intensity at any preset emission angle is greater than a first threshold, adjusting the emission angle of the beam deflection module according to the spot position, so that the laser emitted by the beam deflection module is aligned with a laser receiving device.

[0013] In a possible implementation, the emission angle of the beam deflection module is adjusted according to the light spot position, including: adjusting the emission angle of the beam deflection module in the direction of reducing 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.

[0014] In a third aspect, a laser wireless charging system is provided, comprising a laser emitting device and a laser receiving device as in the first aspect and any embodiment thereof; the laser receiving device comprises a second reflector group, a laser photovoltaic cell, a power conversion circuit and a load circuit; the second reflector group is used to reflect a part of the fluorescence or laser from the beam deflection module of the laser emitting device back to the beam deflection module, and transmit the other part to the laser photovoltaic cell; the power conversion circuit is used to convert the electric energy from the laser photovoltaic cell into power and output it to the load circuit.

[0015] Regarding the technical effects of the second and third aspects, refer to the technical effects of the first aspect and any of its embodiments, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the architecture of a laser wireless charging system provided in an embodiment of the present application Figure 1 ;

[0017] Figure 2 A schematic diagram of a laser principle provided in an embodiment of the present application;

[0018] Figure 3 A schematic structural diagram of a reflector assembly provided in an embodiment of the present application;

[0019] Figure 4 A schematic diagram of the architecture of a laser wireless charging system provided in an embodiment of the present application Figure 2 ;

[0020] Figure 5A schematic diagram of a fluorescence range and an oscillation range provided in an embodiment of the present application;

[0021] Figure 6 A schematic diagram of the architecture of a laser wireless charging system provided in an embodiment of the present application Figure 3 ;

[0022] Figure 7 A schematic diagram of the architecture of a laser wireless charging system provided in an embodiment of the present application Figure 4 ;

[0023] Figure 8 A schematic diagram of the architecture of a laser wireless charging system provided in an embodiment of the present application Figure 5 ;

[0024] Fig. 9 A schematic diagram of a laser emitting device provided in an embodiment of the present application Figure 1 ;

[0025] Fig.10 A schematic diagram of a laser emitting device provided in an embodiment of the present application Figure 2 ;

[0026] Fig.11 A schematic diagram of a laser emitting device provided in an embodiment of the present application Figure 3 ;

[0027] Fig.12 A schematic diagram of the structure of a four-quadrant photoelectric detector provided in an embodiment of the present application;

[0028] Fig.13 A schematic diagram of controlling the rotation angle of a first galvanometer and a second galvanometer provided in an embodiment of the present application;

[0029] Fig.14 A schematic diagram of a scanning method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] Laser wireless energy transmission technology refers to a technology in which a laser transmitting device transmits energy outward using laser as a carrier, and a laser receiving device receives 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.

[0031] The application of laser wireless energy transmission technology to charge laser receiving devices is called laser wireless charging technology. Figure 1As shown, 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 of a certain wavelength, and the laser photovoltaic cell 121 converts the laser energy into electrical energy after receiving the laser. The power conversion circuit 122 converts the voltage generated by the laser photovoltaic cell into the voltage required by the load circuit 123, thereby supplying power to the load circuit 123.

[0032] The laser emitting device may be a laser wireless charger, a laser transmitting tower or other equipment capable of emitting lasers, and the laser receiving device may be a mobile phone, an electric car or other equipment capable of receiving lasers and converting them into electrical energy.

[0033] Laser emitting devices are generally evolved from lasers, so the basic working principle of lasers is described first:

[0034] like Figure 2 As shown, the laser includes a pump source 21, a gain medium (also called a working substance) 22 and a resonant cavity 23. The pump source 21 is used as an energy source 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 back and forth in the resonant cavity 23 and is enhanced in the gain medium 22. Then, the laser light is output at one end of the resonant cavity 23.

[0035] The pump source 21 includes an optical pump source, an electric pump source, etc. A commonly used pump source is a semiconductor laser pump source, which realizes the conversion from electrical energy to light energy.

[0036] The types of gain medium 22 include liquid, gas and solid. Liquid includes, for example, organic solution, gas includes, for example, carbon dioxide, solid includes, for example, semiconductor, crystal material (such as neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal), etc.

[0037] The resonant cavity 23 includes two reflector groups. Photons are reflected back and forth between the two reflector groups and continuously induce stimulated radiation in the gain medium, thereby generating high-intensity laser light. The reflector group is used to return the incident light along the original path or in parallel. One reflector group in the resonant cavity is made into a total reflector, and the other reflector group is made into a partial reflector, so that part of the laser light can be output from the other side of the partial reflector.

[0038] like Figure 3 As shown, the present application does not limit the structure of the reflector assembly, which may be, for example: Figure 3 The retroreflector shown in A in the figure, Figure 3 The mirror group shown in B includes a convex lens and a plane mirror. Figure 3 The lens assembly shown in C in FIG. 1 includes a convex lens and a concave mirror, or, Figure 3The near-spherical reflector with a refractive index greater than or equal to 1.9 and less than or equal to 2.1 shown in D, etc.

[0039] The process of gain medium 22 emitting photons includes spontaneous emission and stimulated emission, and the light emitted by gain medium 22 also includes fluorescence and laser:

[0040] After the gain medium 22 is pumped by the pump source 21, the upper energy level particle number inversion occurs (i.e., the number of atoms on the high energy level E2 is greater than the number of atoms on the low energy level E1), and the inverted upper energy level particles can emit a photon to return to the ground state. This process is spontaneous radiation, and this light is fluorescence. When the resonant cavity 23 does not form resonance, spontaneous radiation fluorescence is dominant, and the spontaneous radiation fluorescence has a solid angle of 4π (i.e., it is emitted in all directions and has no directionality).

[0041] When the resonant cavity begins to resonate, the gain medium 22 is excited by the fluorescence reflected in the resonant cavity, amplifies the light and continues to emit in the original direction. This process is stimulated emission. The amplified light is laser, and its emission direction is the same as the direction of the incident light, so it has good directionality. When the resonant cavity begins to resonate, the spontaneous radiation will be greatly weakened, the fluorescence intensity will decrease, and the laser intensity will increase.

[0042] The above laser including two reflector groups is applied to the field of laser wireless charging, such as Figure 4 As shown, 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, and 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, also includes a maximum power point tracking (MPPT) circuit 4222.

[0043] The working principle of this laser wireless charging system is as follows:

[0044] The first reflector group 412 and the second reflector group 424 form a resonant cavity, wherein the first reflector group 412 is a total reflector and the second reflector group 424 is a partial reflector. The pump source 411, as an energy source, provides energy to the gain medium 412. The gain medium 412 emits and amplifies laser light of a specific wavelength under the pumping. The laser light oscillates back and forth in the resonant cavity, and a portion of the laser light is emitted from the other side of the second reflector group 412. After receiving the laser light, the laser photovoltaic cell 421 converts the laser energy into electrical energy, and the power conversion circuit 422 converts the voltage generated by the laser photovoltaic cell into the voltage required by the load circuit 423, thereby supplying power to the load circuit 423.

[0045] The MPPT circuit 4222 in the power conversion circuit 422 is used to achieve maximum power tracking, so that the laser photovoltaic cell 421 outputs the maximum electric power, and the MPPT 4222 is generally a boost circuit. The DC-DC circuit 4221 is used to convert the voltage output by the MPPT circuit 4222 into the voltage required by the load circuit, and the DC-DC circuit 4221 can be a buck circuit, a boost circuit, or a buck-boost circuit, etc., which have a voltage conversion function.

[0046] Since the reflector can return the incident light along the original path or in parallel within a certain range, as long as the first reflector group, the second reflector group and the gain medium are approximately in a straight line, energy transmission can be achieved, and automatic positioning and tracking of the laser receiving device within a certain range can be achieved. When someone enters the optical path, the resonance of the laser in the resonant cavity stops, so it will not cause harm to people.

[0047] However, due to the reflection range of the reflector and the stability of the resonant cavity, the scanning and tracking range is not very large. Figure 5 As shown, the gain medium 412 emits fluorescence within a certain fluorescence range when pumped. Limited by the stability of the resonant cavity, the second reflector group 424 cannot form a resonant cavity with the first reflector group 413 within the fluorescence range, but can form a resonant cavity with the first reflector group 413 within an oscillation range smaller than the fluorescence range. When the second reflector group 424 (i.e., the laser receiving device 42) moves within the oscillation range, the laser is received due to resonance. When the second reflector group 424 (i.e., the laser receiving device 42) moves out of the oscillation range, the laser cannot be received due to the cessation of resonance.

[0048] To this end, an embodiment of the present application provides another laser wireless charging system, in which a beam deflection module is added to the laser emitting device to expand the oscillation range, and the laser receiving device is scanned within the oscillation range. The laser emitting device detects the light intensity of the fluorescence or laser and the position of the light spot on the detection module. When the laser receiving device is within the oscillation range, the laser emitting device and the laser receiving device form a resonant cavity, and the laser emitting device generates laser. At this time, the light intensity of the laser is greater than the threshold, so as to achieve coarse positioning. Then the laser emitting device adjusts the beam deflection module according to the position of the light spot of the laser on the detection module, so as to adjust the laser power generated by the laser emitting device. Since the beam deflection module can adjust the emission angle of the laser at a large angle, it breaks through the reflection range limitation of the reflector and the stability limitation of the resonant cavity, so that the emission range of the laser of the laser emitting device can be improved, and the range of the laser emitting device tracking the laser receiving device can be expanded.

[0049] like Figure 6-Figure 8 As shown, in Figure 4 Based on the laser wireless charging system shown in the figure: the laser emitting device 41 may include: a detection control module (including a control module 414 and a detection module 415), a pump source 411, and a first reflector group 413, a gain medium 412 and a beam deflection module 416 which are 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.

[0050] Optional, such as Figure 7 and Figure 8 As shown, the laser emitting device 41 may further include a proportional beam splitter 417 disposed in the resonant cavity, and the proportional beam splitter 417 may be disposed on the optical path between the gain medium 412 and the beam deflection module 416 ( Figure 7 ), or, it can be arranged on the optical path between the first reflector group 413 and the gain medium 412 ( Figure 8 ).

[0051] Optional, such as Figure 6-Figure 8 As shown, the laser emitting device 41 may further include a first lens group 418 , and the first lens group 418 may be disposed on an optical path between the gain medium 412 and the beam deflection module 416 .

[0052] Optional, such as Figure 6-Figure 8 As shown, the laser emitting device 41 may further include a partial reflector 419 , and the partial reflector 419 may be disposed on the optical path between the gain medium 412 and the beam deflection module 416 .

[0053] The functions of each device are described below:

[0054] The gain medium 412 is used to be pumped by the pump source 411 and emit fluorescence of a first wavelength (e.g., 1064 nm) to the first reflector group 413 and the beam deflection module 416. After the first reflector group 413 reflects the fluorescence of the first wavelength from the gain medium 412 back to the gain medium, it is emitted through the beam deflection module 416 and can be emitted to the laser receiving device 42. The beam deflection module 416 reflects the fluorescence of the first wavelength injected from outside the device (e.g., reflected from the laser receiving device 42) back to the gain medium 412 and transmits it to the first reflector group 413. When the laser receiving device 42 does not resonate with the laser emitting device 41, the gain medium 412 will emit fluorescence, and part of the fluorescence will be reflected by the beam deflection module 416 to the outside of the laser emitting device 41. This part of the fluorescence is very weak and safe for the human body.

[0055] The gain medium 412 is also used to emit laser light by being stimulated by the resonance between the first reflector group 413 and the laser receiving device 42 (the second reflector group 424). Similar to fluorescence, the first reflector group 413 reflects the laser light of the first wavelength from the gain medium 412 back to the gain medium, and then emits it through the beam deflection module 416, and can be directed to the laser receiving device 42. The beam deflection module 416 reflects the laser light of the first wavelength injected from the outside of the device (for example, reflected from the laser receiving device 42) back to the gain medium 412, and then transmits it to the first reflector group 413.

[0056] Optional, such as Fig. 9 and Fig.10 As shown, the pump source 411 and the gain medium 412 can be arranged separately. For example, the pump source 411 can be an optical pump source. The pump source 411 emits pump light of a second wavelength (e.g., 808 nm) to the gain medium 412. The gain medium 412 is stimulated by the pump light of the second wavelength and emits fluorescence or laser of a first wavelength to the first reflector group 413 and the beam deflection module 416.

[0057] Optional, such as Fig.11 As shown, the pump source 411 and the gain medium 412 may be combined and arranged, for example, the pump source 411 and the gain medium 412 may be electrically pumped semiconductor gain chips.

[0058] Optional, such as Figure 9-11 As shown, the first reflector group 413 may include a convex lens F1 and a plane mirror M1. The distance L1 between the convex lens F1 and the plane mirror M1 is approximately equal to the focal length f1 of the convex lens F1, and the distance L2 between the convex lens F1 and the gain medium is approximately equal to the focal length f1 of the convex lens F1.

[0059] Optional, such as Fig. 9 and Fig.10As shown, high-transmittance films for the second wavelength (e.g., anti-reflective and high-transmittance (AR) films) can be grown on both sides of the plane mirror M1, and high-reflection films for the first wavelength (e.g., high-reflection and low-transmittance (HR) films) can be grown on one side (reflective surface) of the plane mirror M1. High-transmittance films for the first wavelength and the second wavelength can be grown on both sides of the convex lens F1. 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 fluorescence or laser of the first wavelength emitted by the gain medium 412 is reflected back to the gain medium 412.

[0060] Optional, such as Fig. 9 and Fig.10 As shown, a high-transmittance film for the first wavelength and the second wavelength may be grown on the first side of the gain medium 412, and a high-transmittance film for the first wavelength and a high-reflection film for the second wavelength may be grown on the second side of the gain medium 412. The first side of the gain medium 412 is the side facing the first reflector group 413, and the second side of the gain medium 412 is the opposite side of the first side. This allows the pump light of the second wavelength to enter the gain medium 412 from the first side without leaking from the second side, while the fluorescence or laser of the first wavelength can be emitted or injected from the first side and the second side.

[0061] Optional, such as Figure 6 As shown, the first reflector group 413 is also used to transmit a portion of the fluorescence or laser light of the first wavelength to the detection module 415. Fig.11 As shown, the plane mirror M1 can be a partial reflector, for example, the transmittance can be 5% and the reflectance can be 95%. High-transmittance films for the first wavelength are grown on both sides of the convex lens F1, so that part of the fluorescence or laser of the first wavelength can be transmitted to the detection module 415 through the plane mirror M1.

[0062] Optional, such as Fig.11 As shown, the incident surface (or exit surface) of the gain medium 412 can be grown with a high-transmittance film for the first wavelength, and the reflection surface (the interface with the pump source 411) of the gain medium 412 can be grown with a high-reflection film for the first wavelength. This allows the fluorescence or laser of the first wavelength to enter or exit the gain medium, and reduces the loss of the fluorescence or laser of the first wavelength in the gain medium.

[0063] The proportional beam splitter 417 is used to transmit a portion (e.g., 4%) of the fluorescence or laser light of the first wavelength to the detection module 415, and another portion (e.g., 96%) is reflected at a certain angle, and the reflected portion resonates between the first reflector group 413 and the beam deflection module 416. For example, Fig. 9 and Fig.10As shown, the proportional beam splitter 417 can be a partial reflector with a non-perpendicular angle (e.g., 45 degrees) to the laser and with a certain transmittance (e.g., 4%) or reflectance (e.g., 96%). When the laser emitting device and the laser receiving device resonate, since the proportional beam splitter 417 has a certain transmittance, a portion of the laser light of the first wavelength reflected from the laser receiving device 42 will be transmitted to the detection module 415 through the proportional beam splitter 417.

[0064] The detection control module is used to adjust the beam deflection module to multiple preset emission angles in sequence, that is, to scan the laser receiving device by emitting laser in a certain area. The light intensity of the fluorescence or laser at multiple preset emission angles, as well as the spot position of the laser on the detection control module are detected. If the light intensity at any preset emission angle is greater than the first threshold, that is, the laser resonates between the first reflector group 413 and the second reflector group 424 of the laser receiving device, the emission angle of the beam deflection module is adjusted according to the spot position, so that the laser emitted by the beam deflection module is aligned with the laser receiving device, that is, fine adjustment is performed, and the closer the spot position is to the center of the detection control module, the greater the power of the laser.

[0065] The detection module 415 is used to detect the light intensity of the fluorescence or laser of the first wavelength, and the spot position of the laser on the detection module 415. Due to the existence of the oscillation range, the spot position of the laser irradiated to the 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, a four-quadrant photodetector or a photodiode (PD), etc.

[0066] Optionally, in order to avoid interference of stray light on the detection of the light spot position, a bandpass filter for the first wavelength, such as a 1064nm bandpass filter, may be provided on the surface of the detection module 415, or a bandpass coating for the first wavelength may be grown on the surface of the detection module 415. In this way, only light near the first wavelength can be detected by the detection module 415, while light of other wavelengths will not be detected by the detection module 415.

[0067] In a possible implementation, Figure 6 and Fig.11 As shown, when the laser emitting device 41 does not include the proportional beam splitter 417, the detection module 415 can be set on the light-transmitting side of the first reflector group 413, and the first reflector group 413 can transmit a part of the fluorescence or laser of the first wavelength to the detection module 415, and the detection module 415 detects the light intensity and spot position of the fluorescence or laser of the first wavelength.

[0068] In another possible implementation, Figure 7-10As shown, when the laser emitting device 41 includes a proportional beam splitter 417, the proportional beam splitter 417 is used to transmit a portion of the fluorescence or laser of the first wavelength to the detection module 415, and the detection module 415 detects the light intensity of the fluorescence or laser of the first wavelength, as well as the spot position of the laser on the detection module 415.

[0069] The detection principle of the detection module 415 is described below:

[0070] For example, the detection module 415 is a four-quadrant photoelectric detector. Fig.12 As shown, the four-quadrant photodetector is a photoelectric detection device in which four PDs with exactly the same performance are arranged in four quadrants (A, B, C, and D) of rectangular coordinates. When fluorescence or laser irradiates the surface of the four-quadrant photodetector, the PD in each quadrant will generate current, and the current signal is converted into a voltage signal through an external circuit for sampling. When fluorescence or laser irradiates the center of the four-quadrant photodetector, the output current of the PDs in the four quadrants is the same. Assume that the output current of the PD in quadrant A is Ia, the output current of the PD in quadrant B is Ib, the output current of the PD in quadrant C is Ic, and the output current of the PD in quadrant D is Id. The current size corresponds to the light intensity of the fluorescence or laser. The coordinates of the center of mass of the light spot (δ X ,δ Y ) is as follows: Formula 1 and Formula 2:

[0071]

[0072]

[0073] When Ia+Id=Ic+Ib, that is, 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 x of the centroid of the light spot is 0.

[0074] When Ia+Ib=Ic+Id, that is, the sum of the currents on the upper side of the Y axis is equal to the sum of the currents on the lower side of 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 y=0.

[0075] When Ia+Id>Ib+Ic, that is, 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 x of the centroid of the light spot>0.

[0076] When Ib+Ic>Ia+Id, that is, 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 x of the centroid of the light spot is <0.

[0077] When Ia + Ib > Ic + Id, that is, the sum of the currents on the upper side of the Y-axis is greater than the sum of the currents on the lower side of the Y-axis, the centroid of the light spot is located on the positive semi-axis of the Y-axis, that is, the Y-axis coordinate y of the centroid of the light spot is > 0.

[0078] When Ia + Ib < Ic + Id, that is, the sum of the currents on the lower side of the Y-axis is greater than the sum of the currents on the upper side of the Y-axis, the centroid of the light spot is located on the negative semi-axis of the Y-axis, that is, the Y-axis coordinate y of the centroid of the light spot is < 0.

[0079] The light intensity of fluorescence or laser and the position of the light spot can be roughly obtained in the above manner.

[0080] Exemplarily, taking the detection module 415 as a PD, a quadrant photodetector can be formed by multiple PDs, and its principle is the same as that of the quadrant photodetector, which will not be repeated here.

[0081] Exemplarily, taking the detection module 415 as an infrared camera. The infrared camera sends the captured image to the control module 414, and the control module 414 can analyze the image to obtain the brightness and the position of the light spot of the fluorescence or laser of the first wavelength. Among them, the brightness can represent the light intensity. For example, the bright area in the image is the position of the light spot, and by extracting the brightness value of this light spot position, the corresponding light intensity can be obtained.

[0082] Exemplarily, taking the detection module 415 as a PSD. The receiving surface of the PSD is approximately square with a side length of L.

[0083] In a possible implementation manner, the PSD can output four signals X1, X2, Y1, and Y2. X1 and X2 are the voltage signals converted from the photocurrents generated by the light spot detected by the two electrodes on the X-axis of the PSD, and Y1 and Y2 are the voltage signals converted from the photocurrents generated by the light spot detected by the two electrodes on the Y-axis of the PSD.

[0084] In another possible implementation manner, the PSD can output three signals XC, YC, and OUTH1. Among them, XC, YC, and OUTH1 have the following relationship with X1, X2, Y1, and Y2: XC = (X2 + Y1) - (X1 + Y2), YC = (X2 + Y2) - (X1 + Y1), OUTH1 = X1 + X2 + Y1 + Y2.

[0085] Calculating XC / OUTH1 * L / 2 can obtain the light spot position of the light spot in the X direction, and calculating YC / OUTH1 * L / 2 can obtain the light spot position of the light spot in the Y direction. Among them, the coordinate origin is the center of the receiving surface of the PSD, and OUTH1 is the intensity of the light spot. Therefore, the detection module 415 can detect the intensity and the position of the light spot of the fluorescence or laser of the first wavelength.

[0086] Optionally, as Figure 9-11As shown, the beam deflection module 416 may include a first galvanometer 4161 and a second galvanometer 4162. Optionally, a high-reflection film (e.g., a high-reflection, low-transmittance (HR) film) for the first wavelength may be grown on the surface of the first galvanometer 4161 and the second galvanometer 4162. The fluorescence or laser of the first wavelength from the gain medium 412 is reflected by the first galvanometer 4161 and the second galvanometer 4162 in turn and then emitted, and the fluorescence or laser of the first wavelength injected from the laser emitting device is reflected by the second galvanometer 4162 and the first galvanometer 4161 in turn and then 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 angle of the first galvanometer 4161 and the second galvanometer 4162.

[0087] like Fig. 9 As shown, when the positions of the first galvanometer 4161 and the second galvanometer 4162 are fixed, a nearly conical fluorescence range will be formed, and the oscillation range will be smaller than the fluorescence range. Fig.13 As shown, it is assumed that the coordinates of the center of the fluorescence range projected on the plane perpendicular to the motor rotation axis of the first galvanometer 4161 are (x, y), d is the distance from the second galvanometer 4162 to the plane, and e is the distance between the centers of the first galvanometer 4161 and the second galvanometer 4162. Then the rotation angle θx of the first galvanometer 4161 on the X axis satisfies Formula 3, and the rotation angle of the second galvanometer 4162 on the Y axis satisfies Formula 4:

[0088]

[0089] θy=arctan(y / d) Formula 4

[0090] Therefore, the emission angle of the beam deflection module 416 can be adjusted by controlling the rotation angle of the first galvanometer 4161 and the second galvanometer 4162, thereby controlling the scanning path. Fig.14 As shown in the figure, there are several possible scanning paths. The scanning path can be Fig.14 The scanning step by step from the center to the periphery as shown in A in the figure, or it can be Fig.14 The scanning step by step from the periphery to the center as shown in B, or it can be Fig.14 The scan is performed row by row as shown in C, or it can be Fig.14 The column-by-column step scan shown in D, or it can be Fig.14 The step-by-step scanning in the oblique row shown in E is not limited in this application. It should be noted that in order to avoid blind areas, the scanning step should be controlled so that the scanning step is smaller than the width of the oscillation range.

[0091] The partial reflector 419 can partially reflect the fluorescence or laser of the first wavelength to the gain medium 412, thereby reducing the pumping threshold of the laser of the first wavelength. The fluorescence reflected by the partial reflector 419 is relatively weak, and the reflectivity of the partial reflector 419 multiplied by the gain coefficient of the gain medium 412 is less than 1, so that when there is no reflection from the laser receiving device 42, no resonance is formed between the partial reflector 419 and the first reflector 415. 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 resonance can be generated in the resonant cavity and the laser of the first wavelength is emitted.

[0092] The first lens group 418 can adjust the starting range of the laser of the first wavelength, and the starting range includes the starting distance and the starting angle range. By changing the optical parameters of the first lens group 418, such as the focal length or magnification of the lens, the stability of the resonant cavity at different distances and angle ranges can be changed. For example, the smaller the magnification, the closer the starting distance, but the larger the starting angle range; the larger the magnification, the longer the starting distance, but the smaller the starting angle range. For another example, the longer the focal length, the longer the starting distance, but the smaller the starting angle range; the shorter the focal length, the shorter the starting distance, but the larger the starting angle range.

[0093] For example, Fig.10 As shown, the first lens group 418 may include a convex lens F2 and a convex lens F3. The present application does not limit the positional relationship between the partial reflector 419 and each lens in the first lens group. For example, the partial reflector 419 may be disposed between the convex lens F2 and the convex lens F3, or disposed outside the first lens group on a side close to the convex lens F2, or disposed outside the first lens group on a side close to the convex lens F3.

[0094] Optionally, the first focus of the convex lens F2 may be located on the gain medium 412 (for example, at the center of the gain medium 412). It should be noted 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, and the second focus of the convex lens F3 may be located on the reflection surface of the beam deflection module 416 (for example, on the reflection surface of the first galvanometer 4161).

[0095] The working principle of the laser emitting device 41 is as follows:

[0096] The control module 414 controls the pump source 411 to the first pump intensity, and adjusts the beam deflection module 416 to multiple preset emission angles in turn to scan the target area. At this time, the laser emitting device 41 emits fluorescence. This process is a coarse positioning process. Since the laser emitting device 41 has a certain oscillation range, when the laser receiving device 42 is outside the oscillation range, the resonant cavity does not form resonance, and there is no obvious light spot on the detection module 415.

[0097] If at any preset emission angle, the control module 415 detects through the detection module 415 that the light intensity of the fluorescence or laser of the first wavelength is greater than the first threshold, it is considered that the laser receiving device 42 is within the oscillation range of the laser emitting device 41, and the laser emitting device 41 has formed a resonance with the laser receiving device 42. At this time, the laser emitting device 41 emits laser to complete the rough positioning process. At this time, the light spot may be located at the edge of the detection module 415. Although the laser emitting device 41 also transmits energy to the laser receiving device 42 through laser, the laser power is relatively low.

[0098] The control module 414 controls the pump source 411 to be the second pump intensity, and adjusts the emission angle of the beam deflection module 416 according to the spot position of the laser of the first wavelength. Specifically, the control module 414 adjusts the emission angle of the beam deflection module 416 in the direction of reducing the deviation between the spot position and the center of the detection module 415 until the absolute value of the deviation between the spot position and the center of the detection module 415 is less than or equal to a second threshold value, which may be 100 microns, for example.

[0099] When the spot position deviates 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 to eliminate the deviation. In other words, the control module 414 adjusts the beam deflection module 416 so that the optical axis of the laser emitting device 41 is directly opposite to the laser receiving device 42. At this time, the spot position is located at the center of the detection module 415. At this time, the laser emitting device 41 transmits energy to the laser receiving device 42 through the laser, and the laser power is the highest.

[0100] Optionally, after adjusting the beam deflection module 416 to the target emission angle, if the control module 415 detects that the light intensity of the fluorescence or laser of the first wavelength is less than the second threshold, the control module 414 controls the pump source 411 to the first pump intensity, and sequentially adjusts the beam deflection module 416 to multiple emission angles, that is, the laser emitting device 41 loses the laser receiving device 42, and re-rough positioning is performed. The second threshold is less than or equal to the first threshold.

[0101] If the light spot is located at the center of the detection module 415, the detection module 415 can determine the location by:

[0102] If the detection module 415 is a four-quadrant photodetector or PD, the currents of the four quadrants of the PD are the same, ie, Ia=Ib=Ic=Id.

[0103] If the detection module 415 is an infrared camera, the bright area is located at the center of the image.

[0104] If the detection module 415 is PSD, XC / OUTH1*L / 2 and YC / OUTH1*L / 2 are equal to the coordinates of the coordinate origin.

[0105] The second pump intensity may be the same as or different from the first pump intensity. In a possible implementation, the first pump intensity is less than the second pump intensity, that is, during the scanning process, scanning is performed with a smaller pump intensity to reduce the power consumption of the coarse positioning process; the laser emitting device 41 transmits energy to the laser receiving device 42 through laser, and transmits energy with a higher power to improve the transmission efficiency. Alternatively, the second pump intensity is adjusted according to the required power fed back by the laser receiving device 42.

[0106] The embodiments of the present application provide a laser emitting device, a laser emitting method and a laser wireless charging system, wherein the laser emitting device includes: a control module, a detection module, a pump source, and a first reflector group, a gain medium and a beam deflection module arranged in a resonant cavity; the control module is electrically connected to the detection module, the pump source and the beam deflection module; the gain medium is used to emit fluorescence when pumped by the pump source, and to emit laser when stimulated by the resonance of the fluorescence between the first reflector group and the laser receiving device; the beam deflection module is used to emit the fluorescence or laser emitted by the gain medium, and to inject the fluorescence or laser reflected by the laser receiving device into the gain medium; the control module is used to adjust the beam deflection module to multiple preset emission angles in sequence; the detection module is used to detect the light intensity of the fluorescence or laser, and the spot position of the laser on the detection module; the control module is also used to adjust the emission angle of the beam deflection module according to the spot position if the light intensity is greater than the first threshold at any preset emission angle. Since the beam deflection module can adjust the laser emission angle at a large angle, it is not subject to the reflection range limitation of the reflector and the stability limitation of the resonant cavity, so the emission range of the laser of the laser emitting device can be improved.

[0107] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0108] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0109] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0110] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0111] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0112] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A laser emitting device, characterized in that: include: A detection control module, a pump source, and a first reflector group, a gain medium and a beam deflection module arranged on the optical path; The gain medium is used to emit fluorescence when pumped by the pump source, and to emit laser when stimulated by the resonance of the fluorescence between the first reflector group and the laser receiving device; The beam deflection module is used to emit the fluorescence or laser emitted by the gain medium, and to inject the fluorescence or laser reflected by the laser receiving device into the gain medium; The detection control module is used to: sequentially adjusting the beam deflection module to a plurality of preset emission angles; Detecting the light intensity of the fluorescence or the laser at the plurality of preset emission angles, and the spot position of the laser on the detection control module; If the light intensity is greater than a first threshold at any preset emission angle, adjusting the emission angle of the beam deflection module according to the light spot position so that the laser emitted by the beam deflection module is aligned with the laser receiving device; The detection control module includes a control module and a detection module, and the control module is used to adjust the emission angle of the beam deflection module in the direction of reducing 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 according to claim 1, characterized in that: The detection control module includes a control module, and the beam deflection module includes a first galvanometer and a second galvanometer; the fluorescence or laser from the gain medium is reflected by the first galvanometer and the second galvanometer in turn and then emitted, and the fluorescence or laser emitted from outside the laser emitting device is reflected by the second galvanometer and the first galvanometer in turn and then transmitted back 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 and the second galvanometer.

3. The laser emitting device according to claim 1 or 2, characterized in that: The detection control module includes a detection module, and the laser emitting device also includes a proportional beam splitter arranged on the optical path, and the proportional beam splitter is used to transmit a part of the fluorescence or laser to the detection module; the detection module is used to detect the light intensity and spot position of a part of the fluorescence or laser.

4. The laser emitting device according to claim 3, characterized in that: The proportional beam splitter is arranged on the optical path between the gain medium and the beam deflection module.

5. The laser emitting device according to claim 3, characterized in that: The proportional beam splitter is arranged on an optical path between the first reflector group and the gain medium.

6. The laser emitting device according to claim 1 or 2, characterized in that: The detection control module includes a detection module. The first reflector group is also used to transmit a part of the fluorescence or laser to the detection module. The detection module is used to detect the light intensity and spot position of the transmitted fluorescence or laser.

7. The laser emitting device according to claim 1 or 2, characterized in that: The laser emitting device further comprises a first lens group, which is arranged on the optical path between the gain medium and the beam deflection module, and is used to adjust the oscillation distance and oscillation angle range of the laser.

8. The laser emitting device according to claim 1 or 2, characterized in that: The laser emitting device further comprises a partial reflector, which is arranged on the optical path between the gain medium and the beam deflection module, and can partially reflect the fluorescence or laser toward the gain medium.

9. The laser emitting device according to claim 1 or 2, characterized in that: The pump source and the gain medium are collectively configured as an electrically pumped semiconductor gain chip.

10. The laser emitting device according to claim 1 or 2, characterized in that: The detection control module includes a detection module, and the detection module includes a position sensor PSD, an infrared camera, a four-quadrant photoelectric detector or a photodiode.

11. The laser emitting device according to claim 1 or 2, characterized in that: The first reflector group is a corner cone reflector, a mirror group including a convex lens and a plane mirror, a mirror group including a convex lens and a concave mirror, or a near-spherical reflector with a refractive index greater than or equal to 1.9 and less than or equal to 2.

1.

12. A laser emitting method, characterized in that: Applied to the laser emitting device according to any one of claims 1 to 11, the method comprises: sequentially adjusting the beam deflection module of the laser emitting device to a plurality of preset emitting angles; Detecting the light intensity of the fluorescence or the laser at the plurality of preset emission angles, and the spot position of the laser on the detection control module of the laser emission device; If the light intensity is greater than a first threshold at any preset emission angle, the emission angle of the beam deflection module is adjusted according to the light spot position so that the laser emitted by the beam deflection module is aligned with the laser receiving device.

13. A laser wireless charging system, characterized in that: It comprises a laser emitting device and a laser receiving device as described in any one of claims 1 to 11; the laser receiving device comprises a second reflector group, a laser photovoltaic cell, a power conversion circuit and a load circuit; the second reflector group is used to reflect a part of the fluorescence or laser from the beam deflection module of the laser emitting device back to the beam deflection module, and transmit the other part to the laser photovoltaic cell; the power conversion circuit is used to convert the electric energy from the laser photovoltaic cell into power and output it to the load circuit.

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