Acousto-optic deflection module, distance measuring device and electronic equipment based on diffuser beam expansion

Abstract

The present application provides an acousto-optic deflection module based on diffuser beam expansion, comprising a light source module, an acousto-optic deflection module, a converging optical device, a liquid crystal polarization grating module and a diffuser. The light source module comprises a light emitting unit and a super lens for collimating a light beam. The acousto-optic deflection module deflects a light beam to a plurality of different preset deflection angles within a preset first deflection angle range along a first direction according to the frequency of an applied sound wave. The converging optical device is configured to converge the deflected light beam. The liquid crystal polarization grating module is configured to further deflect the deflected and converged light beam by corresponding different preset deflection angles at a plurality of moments to form sensing light beams with different emission directions. The diffuser expands the divergence angle of the sensing light beam along the second direction to form a long strip sensing light beam, the length direction of which is parallel to a second direction perpendicular to the first direction. The present application also provides a distance measuring device and an electronic device.

Description

Technical Field

[0001] The present application belongs to the field of photoelectric detection, and in particular relates to an acousto-optic deflection module, a distance measuring device and an electronic device based on diffuser beam expansion. Background Art

[0002] The Time of Flight (ToF) measurement principle calculates the distance and other three-dimensional information of an object based on the flight time of the detection light reflected by the object in the measurement scene. Due to the advantages of long sensing distance, high accuracy and low energy consumption, ToF measurement is widely used in consumer electronics, smart driving, AR / VR and other fields.

[0003] The detection device that uses the ToF measurement principle for ranging has a limited field of view, and needs to obtain a larger detection range by continuously changing the emission direction of the detection light for scanning. At present, one way to change the emission direction of the detection light is to use a mechanical structure to rotate the detection device. However, this method often requires multiple discrete components to be assembled into a mechanical rotation structure. The optical path debugging and assembly of the transmission / reception are complex, and the mechanical rotation structure is also prone to damage and misalignment. In addition, the large size of the mechanical rotation structure affects the appearance of the terminal device using it. Another way to change the emission direction of the detection light is a hybrid solid-state solution, which mainly uses a vibrating component to drive the optical component to change the emission direction of the detection light. Although the cost and size of the hybrid solid-state solution are significantly reduced compared to the mechanical rotation solution, the reliability of the system is still low because the vibrating component is also prone to damage, which limits the application scenarios of the detection device. Summary of the invention

[0004] In view of this, the present application provides an acousto-optic deflection module, a distance measuring device and an electronic device based on diffuser beam expansion that can improve the problems of the prior art.

[0005] In a first aspect, the present application provides an acousto-optic deflection module based on diffuser beam expansion, which is configured to emit a sensing light beam for three-dimensional information detection to a detection range, and includes:

[0006] Light source module, including:

[0007] one or more light emitting units configured to emit a light beam; and

[0008] A superlens configured to collimate the light beam emitted by the light emitting unit;

[0009] an acousto-optic deflection module configured to receive the collimated light beam and deflect the light beam to a plurality of different preset deflection angles within a preset first deflection angle range along a first direction according to an applied acoustic wave frequency;

[0010] A converging optical device configured to converge the light beam deflected by the acousto-optic deflection module;

[0011] A liquid crystal polarization grating module is configured to further deflect the deflected and converged light beams at different preset deflection angles at multiple times to form sensing light beams with different emission directions; and

[0012] A diffuser is arranged on the light-emitting side of the liquid crystal polarization grating module, and a microstructure capable of modulating a light beam is formed on the diffuser. The diffuser is configured to expand the divergence angle of the sensing light beam along the second direction to form a long strip sensing light beam, and the direction in which the sensing light beam has a maximum size is defined as its length direction. The length direction of the long strip sensing light beam is parallel to the second direction, and the second direction and the first direction are arranged perpendicular to each other.

[0013] In a second aspect, the present application provides a distance measuring device configured to detect the distance of an object within a preset detection range. The distance measuring device includes a receiving module, a processing circuit, and the acousto-optic deflection module as described above. The receiving module is configured to sense the light signal from the detection range and output a corresponding light sensing signal, and the processing circuit is configured to analyze and process the light sensing signal to obtain three-dimensional information of the object within the detection range.

[0014] In a third aspect, the present application provides an electronic device, comprising an application module and the distance measuring device as described above. The application module is configured to implement corresponding functions according to the detection result of the distance measuring device.

[0015] Beneficial effects of this application:

[0016] Compared with the deflection of the sensing light beam through mechanical rotation schemes and hybrid solid-state schemes, the present application realizes continuous deflection of the sensing light beam within a preset deflection angle range through a pure solid-state acousto-optic deflection module, which does not rely on the rotation and vibration of components and has the beneficial effects of better reliability and compact size. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings.

[0018] Figure 1 A schematic diagram of functional modules of an electronic device provided in one embodiment of the present application.

[0019] Figure 2 for Figure 1 A schematic diagram of functional modules of an embodiment of the ranging device described in FIG.

[0020] Figure 3 for Figure 2Schematic diagram of a statistical histogram obtained by the processing circuit described in .

[0021] Figure 4 for Figure 2 A schematic diagram of a portion of the optical path of an embodiment of the acousto-optic deflection module described in FIG.

[0022] Figure 5 for Figure 2 A schematic diagram of a portion of the optical path of another embodiment of the acousto-optic deflection module described in FIG.

[0023] Figure 6 for Figure 2 A schematic diagram of a portion of the optical path of another embodiment of the acousto-optic deflection module described in FIG.

[0024] Figure 7 for Figure 2 Schematic diagram of the structure of the acousto-optic deflection module described in.

[0025] Figure 8 for Figure 4 Schematic diagram of the structure of the LCPG unit in the LCPG module described in .

[0026] Fig. 9 A schematic diagram of the structure of a binary cascaded LCPG module provided in one embodiment of the present application.

[0027] Fig.10 A schematic diagram of the structure of a binary-like cascaded LCPG module provided in one embodiment of the present application.

[0028] Fig.11 A schematic diagram of the structure of a ternary cascaded LCPG module provided in one embodiment of the present application.

[0029] Fig.12 A schematic diagram of the structure of a binary cascaded passive LCPG unit provided in one embodiment of the present application.

[0030] Fig.13 for Figure 2 A structural schematic diagram of an embodiment of the acousto-optic deflection module described in FIG.

[0031] Fig.14 for Figure 2 A structural schematic diagram of another embodiment of the acousto-optic deflection module described in .

[0032] Fig.15 This is a signal timing diagram of a distance measuring device provided in an embodiment of the present application when performing detection.

[0033] Fig.16 A schematic diagram of the structure of a ranging device provided in one embodiment of the present application as an automotive laser radar. DETAILED DESCRIPTION

[0034] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. In the description of the present application, it should be understood that the terms "first" and "second" are only used for description and cannot be understood as indicating or implying relative importance or implicitly indicating the number or arrangement order of the indicated technical features. Thus, the technical features defined as "first" and "second" may explicitly or implicitly include one or more of the technical features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0035] In the description of this application, it should be noted that, unless otherwise clearly specified or limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] The disclosure below provides many different embodiments or examples to implement the different structures of the present application. In order to simplify the disclosure of the present application, only the components and settings of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the present application. In addition, the present application may reuse reference numerals and / or reference letters in different examples, and this repetition is to simplify and clearly state the present application, which itself does not indicate the specific relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and materials provided in the description below are only examples for implementing the technical solutions of the present application, but those of ordinary skill in the art should be aware that the technical solutions of the present application may also be implemented by other processes and / or other materials not described below.

[0037] Further, described features, structures can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided so that the embodiments of the present application can be fully understood. However, those skilled in the art will appreciate that, even without one or more of the specific details, or adopting other structures, components etc., the technical scheme of the present application can also be put into practice. In other cases, known structures or operations are not shown or described in detail to avoid blurring the key points of the present application.

[0038] The embodiment of the present application provides an acousto-optic deflection module based on diffuser beam expansion, which is configured to emit a sensing light beam for three-dimensional information detection to a detection range, and includes a light source module, an acousto-optic deflection module, a converging optical device, a liquid crystal polarization grating module and a diffuser. The light source module includes one or more light-emitting units and a super lens, the light-emitting unit is configured to emit a light beam, and the super lens is configured to collimate the light beam emitted by the light-emitting unit. The acousto-optic deflection module is configured to receive the collimated light beam and deflect the light beam to a plurality of different preset deflection angles along a first direction within a preset first deflection angle range according to the applied sound wave frequency. The converging optical device is configured to converge the light beam deflected by the acousto-optic deflection module. The liquid crystal polarization grating module is configured to further deflect the deflected and converged light beams at corresponding different preset deflection angles at multiple times to form sensing light beams with different emission directions. The diffuser is arranged on the light-emitting side of the liquid crystal polarization grating module, and a microstructure capable of modulating a light beam is formed on the diffuser, and is configured to expand the divergence angle of the sensing light beam along the second direction to form a long strip sensing light beam, and the direction in which the sensing light beam has a maximum size is defined as its length direction, and the length direction of the long strip sensing light beam is parallel to the second direction, and the second direction and the first direction are arranged perpendicular to each other.

[0039] Optionally, in some embodiments, the first direction is a horizontal direction, and the second direction is a vertical direction; or, the first direction is a vertical direction, and the second direction is a horizontal direction.

[0040] Optionally, in some embodiments, the diffuser is a refractive diffuser, and the microstructure realizes the function of expanding the divergence angle of the sensing light beam along a preset direction by refracting the passing light beam.

[0041] Optionally, in some embodiments, the diffuser is a diffraction diffuser, and the microstructure realizes the function of expanding the divergence angle of the sensing light beam along a preset direction by diffracting the passing light beam.

[0042] Optionally, in some embodiments, a plurality of preset deflection angles of the light beam deflected by the liquid crystal polarization grating module form an arithmetic progression according to a preset first angle interval, and the first deflection angle range is greater than or equal to the first angle interval.

[0043] Optionally, in some embodiments, the liquid crystal polarization grating module includes a plurality of liquid crystal polarization grating units arranged in sequence along the exit direction of the light beam, each liquid crystal polarization grating unit includes a liquid crystal half-wave plate and a liquid crystal polarization grating plate, and the deflection angle of the passing light beam by the liquid crystal polarization grating plates increases step by step in the order of being arranged in sequence along the exit direction of the light beam in a natural number power of two, and the value of the natural number is the serial number of the liquid crystal polarization grating plate minus one, and the liquid crystal polarization grating module controls the preset deflection angle of the light beam after passing through the liquid crystal polarization grating plate by changing the diffraction state of the light beam passing through the liquid crystal polarization grating plate.

[0044] Optionally, in some embodiments, the liquid crystal polarization grating module includes a plurality of liquid crystal polarization grating units arranged in sequence along the exit direction of the light beam, each liquid crystal polarization grating unit includes a liquid crystal half-wave plate and a liquid crystal polarization grating plate, and the deflection angle of the passing light beam by the liquid crystal polarization grating plates increases step by step in the order of being arranged in sequence along the exit direction of the light beam in a natural number power of three, and the value of the natural number is the serial number of the liquid crystal polarization grating plate minus one, and the liquid crystal polarization grating module controls the preset deflection angle of the light beam after passing through the liquid crystal polarization grating plate by changing the diffraction state of the light beam passing through the liquid crystal polarization grating plate.

[0045] Optionally, in some embodiments, the liquid crystal polarization grating module includes a liquid crystal half-wave plate and a plurality of liquid crystal polarization grating plates arranged in sequence along the exit direction of the light beam, and the deflection angle of the light beam by the liquid crystal polarization grating plates gradually increases in the order of arrangement in sequence along the exit direction of the light beam, and the difference in the deflection angle of the light beam between one liquid crystal polarization grating plate and an adjacent previous liquid crystal polarization grating plate increases step by step in the order of arrangement in sequence along the exit direction of the light beam by a natural number power of two, and the value of the natural number is the serial number of the liquid crystal polarization grating plate minus one, and the liquid crystal polarization grating module controls the preset deflection angle of the light beam after passing through the liquid crystal polarization grating plate by changing the diffraction state of the light beam passing through the liquid crystal polarization grating plate.

[0046] Optionally, in some embodiments, the light source module further includes a beam reduction optical device, which is configured to reduce the light beam collimated by the superlens to a preset size before transmitting it to the acousto-optic deflection module.

[0047] Optionally, in some embodiments, the light source module further includes a linear polarizer, which is arranged on the optical path of the light beam before it enters the acousto-optic deflection module and is configured to convert the light beam into linear polarized light with a preset polarization state before entering the acousto-optic deflection module.

[0048] Optionally, in some embodiments, the light source module further includes a polarization beam splitter, a polarization direction adjustment member and a light guide member, the polarization beam splitter is arranged on the optical path before the light beam enters the acousto-optic deflection module, the polarization beam splitter decomposes the passing light beam into a first polarized beam and a second polarized beam, the first polarized beam has a first polarization direction, and the second polarized beam has a second polarization direction different from the first polarization direction, the light guide member is configured to guide the propagation direction of the first polarized beam or the second polarized beam, or to guide the propagation direction of both the first polarized beam and the second polarized beam, so that the first polarized beam and the second polarized beam are respectively incident on the acousto-optic deflection module along different optical paths, and the polarization direction adjustment member is configured to change the polarization direction of the first polarized beam or the second polarized beam, so that both enter the acousto-optic deflection module with the same preset polarization direction.

[0049] Optionally, in some embodiments, there is a preset time difference between the moments when the decomposed first polarized light beam and the second polarized light beam respectively arrive at the acousto-optic deflection module.

[0050] Optionally, in some embodiments, the first polarized light beam propagates through the polarization beam splitter to the acousto-optic deflection module along the main optical axis where the incident direction of the light beam is located when the light beam is incident on the polarization beam splitter, and the polarization direction adjusting member is arranged on the main optical axis and is configured to change the first polarization direction of the first polarized light beam to the second polarization direction.

[0051] Optionally, in some embodiments, after passing through the polarization beam splitter, the second polarized light beam propagates to the acousto-optic deflection module along a side branch light path that deviates from the main optical axis where the incident direction of the light beam is located when it is incident on the polarization beam splitter, and the polarization direction adjusting component is arranged on the side branch light path, and is configured to change the second polarization direction of the second polarized light beam into the first polarization direction.

[0052] Optionally, in some embodiments, the polarization direction adjusting member includes a liquid crystal layer, and is configured to change the polarization direction of the passing light beam by adjusting the orientation of liquid crystal molecules in the liquid crystal layer.

[0053] Optionally, in some embodiments, the second polarized light beam enters the acousto-optic deflection module along a direction parallel to the first polarized light beam after being guided by the light guide, and the incident points of the first polarized light beam and the second polarized light beam on the acousto-optic deflection module are both located within a preset incident area on the acousto-optic deflection module.

[0054] The embodiment of the present application also provides a distance measuring device, which is configured to detect three-dimensional information of an object within a preset detection range, including the above-mentioned acousto-optic deflection module, and also includes a receiving module and a processing circuit. The distance measuring device also includes a receiving module and a processing module, the receiving module is configured to sense the light signal from the detection range and output a corresponding light sensing signal, and the processing module is configured to analyze and process the light sensing signal to obtain the three-dimensional information of the object within the detection range.

[0055] An embodiment of the present application also provides an electronic device, which includes the distance measuring device. The electronic device implements the corresponding function based on the three-dimensional information obtained by the distance measuring device. The electronic device is, for example, a mobile phone, a car, a robot, an access control / monitoring system, a smart door lock, a drone, etc. The three-dimensional information is, for example, proximity information, depth information, distance information, coordinate information, etc. of an object within the detection range. Among them, the three-dimensional information can be used, for example, in 3D modeling, face recognition, automatic driving, machine vision, monitoring, drone control, augmented reality (AR) / virtual reality (VR), simultaneous localization and mapping (SLAM), object proximity judgment and other fields, and the present application does not limit this.

[0056] The distance measuring device may be, for example, a laser radar, which may be used to obtain three-dimensional information of objects within the detection range. The laser radar is used, for example, in the fields of intelligent driving vehicles, intelligent driving aircraft, 3D printing, VR, AR, service robots, etc. Taking an intelligent driving vehicle as an example, a laser radar is set in the intelligent driving vehicle, and the laser radar can scan the surrounding environment by quickly and repeatedly emitting a laser beam to obtain point cloud data reflecting the morphology, position and movement of one or more objects in the surrounding environment. Specifically, the laser radar emits a laser beam to the surrounding environment, and receives an echo beam reflected by each object in the surrounding environment. The distance / depth information of each object is determined by calculating the time delay (i.e., the flight time) between the emission time of the laser beam and the return time of the echo beam. At the same time, the laser radar can also determine the angle information describing the orientation of the laser beam detection range, combine the distance / depth information of each object with the angle information of the laser beam, and generate a three-dimensional map including each object in the scanned surrounding environment, and the three-dimensional map can be used to guide the intelligent driving of the unmanned vehicle.

[0057] Hereinafter, embodiments in which the distance measuring device is applied to electronic equipment will be described in detail with reference to the accompanying drawings.

[0058] Figure 1It is a schematic diagram of functional modules of the distance measuring device provided in an embodiment of the present application applied to an electronic device. Figure 2 It is a schematic diagram of the functional modules of the distance measuring device provided in the embodiment of the present application.

[0059] Reference Figure 1 and Figure 2 , the electronic device 1 includes a distance measuring device 10. The distance measuring device 10 can detect an object 2 within a detection range to obtain three-dimensional information of the object 2. The detection range can be defined as a three-dimensional space range in which the distance measuring device 10 can effectively detect three-dimensional information, which can also be referred to as the field of view of the distance measuring device 10. The three-dimensional information is, for example, but not limited to, one or more of the proximity information of the object 2, the depth information of the surface of the object 2, the distance information of the object 2, and the spatial coordinate information of the object 2.

[0060] The electronic device 1 may include an application module 20, which is configured to perform preset operations or implement corresponding functions according to the detection results of the distance measuring device 10, such as but not limited to: judging whether an object 2 appears in a preset detection range in front of the electronic device 1 according to the proximity information of the object 2; or controlling the movement of the electronic device 1 to avoid obstacles according to the distance information of the object 2; or implementing 3D modeling, face recognition, machine vision, etc. according to the depth information of the surface of the object 2. The electronic device 1 may also include a storage medium 30, which may provide support for the storage needs of the electronic device 1 and / or the distance measuring device 10 during operation. The electronic device 1 may also include a processor 40, which may provide support for the data processing needs of the electronic device 1 and / or the distance measuring device 10 during operation.

[0061] Optionally, in some embodiments, the distance measuring device 10 may be, for example, a dToF measuring device for three-dimensional information sensing based on the direct time of flight (dToF) principle. The dToF measuring device may emit a sensing beam within a detection range and receive a sensing beam reflected by an object 2 within the detection range. The time difference between the emission time and the reception time of the reflected sensing beam is called the flight time t of the sensing beam. The three-dimensional information of the object 2 may be obtained by calculating half of the distance traveled by the sensing beam within the flight time t. , where c is the speed of light.

[0062] Optionally, in some other embodiments, the distance measuring device 10 may also be an indirect time of flight (iToF) measuring device that performs three-dimensional information sensing based on the indirect time of flight (iToF) measurement principle. The iToF measuring device obtains the three-dimensional information of the object 2 by comparing the phase difference between the sensing light beam when it is emitted and when it is reflected back and received.

[0063] In the following embodiments of the present application, the distance measuring device 10 is mainly described as a dToF measurement device as an example.

[0064] Alternatively, if Figure 2 As shown, the distance measuring device 10 includes an acoustic-optical deflection module 12, a receiving module 14 and a processing circuit 15. The acoustic-optical deflection module 12 is configured to emit a sensing light beam to the detection range to detect the three-dimensional information of the object 2 within the detection range, wherein part of the sensing light beam will be reflected by the object 2 and returned, and the sensing light beam reflected back carries the three-dimensional information of the object 2, wherein part of the sensing light beam reflected back can be sensed by the receiving module 14 to obtain the three-dimensional information of the object 2. The receiving module 14 is configured to sense the light signal from the detection range and output the corresponding light sensing signal, and the three-dimensional information detection of the object 2 within the detection range can be realized by analyzing the light sensing signal. It can be understood that the light signal sensed by the receiving module 14 can be a photon, for example, including the photon of the sensing light beam reflected back by the object 2 within the detection range and the photon of the ambient light within the detection range. The processing circuit 15 is configured to analyze and process the light sensing signal to obtain the moment when the sensing light beam is sensed by the receiving module 14, and obtain the three-dimensional information of the object 2 according to the time difference between the emission moment of the sensing light beam and the moment when the sensing light beam is reflected back.

[0065] The processing circuit 15 may be disposed on the distance measuring device 10. Optionally, in some other embodiments, all or part of the functional units of the processing circuit 15 may also be disposed on the electronic device 1.

[0066] Optionally, the sensing light beam may be a laser pulse with a preset frequency. The acousto-optic deflection module 12 is configured to periodically emit the laser pulse as the sensing light beam at a preset frequency within a detection frame.

[0067] Optionally, the sensing light beam is, for example, visible light, infrared light or near infrared light, and the wavelength range is, for example, 390 nanometers (nm)-780 nm, 700 nm-1400 nm, 800 nm-1000 nm, 900 nm-1600 nm.

[0068] Please also read Figure 2 and Figure 3 , Figure 3 for Figure 2 Schematic diagram of a statistical histogram obtained by the processing circuit 15. Optionally, in some embodiments, the processing circuit 15 may include a timing unit 152, a statistical unit 154, a flight time acquisition unit 156 and a three-dimensional information acquisition unit 158.

[0069] The timing unit 152 is configured to determine the receiving time when the receiving module 14 senses the light signal. The distance measuring device 10 emits multiple sensing light beams through the acousto-optic deflection module 12 during the detection process. The timing unit 152 starts timing each time the acousto-optic deflection module 12 emits a sensing light beam to record the receiving time when the receiving module 14 senses the light signal between two adjacent sensing light beam emissions. During this period, the receiving module 14 outputs a corresponding light sensing signal each time it receives a light signal. The timing unit 152 records the receiving time of the sensed light signal according to the light sensing signal output by the receiving module 14, and counts in the time bin corresponding to the receiving time to form a corresponding light signal count. Among them, the time bin is the minimum time unit Δt at which the timing unit 152 records the moment when the light sensing signal is generated, which can reflect the accuracy of the timing unit 152 in recording the time of the light signal. The finer the time bin, the higher the accuracy of the recorded time. Optionally, the timing unit 152 can realize the timing function through a time-to-digital converter (TDC) 1522. The TDC 1522 may be connected to the corresponding photosensitive pixel 142, and may be configured to record the reception time of the sensed light signal according to the light sensing signal generated by the corresponding photosensitive pixel 142. For example, the TDC 1522 may be synchronously triggered to start timing each time the sensing light beam is emitted, and then stop timing in response to the light sensing signal generated by the corresponding photosensitive pixel 142, and the timing period may be used as the reception time of the light signal corresponding to the light sensing signal that stimulates the light sensing signal.

[0070] Optionally, in some embodiments, the timing unit 152 may include a counting memory 1524, which has a counting storage space allocated according to the time bins, and each time the TDC 1522 records the reception time of an optical signal, it accumulates one in the counting storage space of the corresponding time bin.

[0071] The statistical unit 154 is configured to count the accumulated optical signal counts in each time bin to obtain a statistical histogram that can reflect the distribution of the number of optical signals sensed by the receiving module 14 over time. Figure 3 As shown, the horizontal axis of the statistical histogram represents the timestamp of each corresponding time bin, and the vertical axis of the statistical histogram represents the accumulated optical signal count value in each corresponding time bin. Optionally, the statistical unit 154 may include a histogram circuit 1544 (see Figure 2 ), the histogram circuit 1544 is configured to count the light signal counts in each time bin to generate a statistical histogram. It should be understood that the statistical unit 154 performs statistical analysis on the corresponding accumulated light signal counts during multiple emission of the sensing light beam in one detection frame. In order to make the counts have mathematical statistical significance, the emission times of the sensing light beam in one detection frame may be as many as hundreds, thousands, tens of thousands, hundreds of thousands, or even millions of times.

[0072] During the sensing process, a large number of ambient light photons will also be sensed by the receiving module 14 to generate corresponding light signal counts. The probability of these ambient light photons being sensed and leaving counts in each time bin tends to be the same, forming a noise background (Noise Level) within the detection range. In scenes with high ambient light intensity, the average level of the noise background measured is relatively high, and in scenes with low ambient light, the average level of the noise background measured is relatively low. On this basis, the light signal count generated by the sensing light beam reflected from the object 2 is sensed and superimposed on the noise background, so that the light signal count in the time bin corresponding to the moment when the sensing light beam is sensed will be significantly higher than the light signal count in other time bins, thereby forming a prominent signal peak. It can be understood that the height of the count value of the signal peak will be affected by factors such as the optical power of the sensing light beam, the reflectivity of the object 2, and the detection range of the ranging device 10, and the width of the signal peak will be affected by factors such as the pulse width of the emitted sensing light beam, the photoelectric conversion element of the receiving module 14, and the time jitter of the TDC1522. Thus, the flight time acquisition unit 156 can obtain the flight time of the relevant sensing light beam reflected by the object 2 according to the time difference between the time stamp t1 of the time bin corresponding to the peak value of the signal peak and the emission time t0 of the relevant sensing light beam generating the signal peak. The three-dimensional information acquisition unit 158 ​​can be configured to obtain the three-dimensional information between the object 2 reflecting the sensing light beam and the distance measuring device 10 according to the flight time of the sensing light beam determined by the statistical histogram, for example: the distance between the object 2 within the detection range and the distance measuring device 10.

[0073] It should be understood that the acousto-optic deflection module 12 and the receiving module 14 are arranged side by side, the light-emitting surface of the acousto-optic deflection module 12 and the light-entering surface of the receiving module 14 are both facing the same side of the distance measuring device 10, and the distance between the acousto-optic deflection module 12 and the receiving module 14 can be, for example, 2 mm to 20 mm. Since the acousto-optic deflection module 12 and the receiving module 14 are relatively close to each other, although the emission path of the sensing light beam from the acousto-optic deflection module 12 to the object 2 and the return path from the object 2 to the receiving module 14 after reflection are not completely equal, both are much larger than the distance between the acousto-optic deflection module 12 and the receiving module 14, and can be regarded as approximately equal. Therefore, the distance between the object 2 and the distance measuring device 10 can be calculated according to the product of half of the flight time t of the sensing light beam reflected back by the object 2 and the speed of light c.

[0074] The receiving module 14 may include a photoelectric sensor 140 and a receiving optical device 144. The receiving optical device 144 is disposed on the light incident side of the photoelectric sensor 140 and is configured to transmit the optical signal from the detection range to the photoelectric sensor 140 for sensing. For example, in some embodiments, the receiving optical device 144 includes a receiving lens (not shown). Optionally, the receiving lens may include a lens or multiple lenses. The photoelectric sensor 140 is configured to sense the optical signal transmitted from the detection range through the receiving optical device 144 and output a corresponding optical sensing signal.

[0075] Optionally, in some embodiments, the receiving module 14 may also include a peripheral circuit (not shown) composed of one or more devices such as a signal amplifier and an analog-to-digital converter (ADC), and the peripheral circuit may be partially or fully integrated in the photoelectric sensor 140.

[0076] Optionally, in some embodiments, the photoelectric sensor 140 includes, for example, a single photosensitive pixel 142 or includes a plurality of photosensitive pixels 142 to form a photosensitive pixel array. The detection range of the distance measuring device 10 may include a plurality of detection areas respectively located at different positions. Optionally, the photosensitive pixel 142 of the photoelectric sensor 140 has a corresponding detection area in the detection range, and the light signal returned from the detection area is propagated to the corresponding photosensitive pixel 142 through the receiving optical device 144 for sensing. That is, the detection area corresponding to the photosensitive pixel 142 can be regarded as the spatial range covered by the field of view formed by the photosensitive pixel 142 through the receiving optical device 144. It should be understood that the light signal returned from the detection area includes the sensing light beam projected to the detection area and reflected back by the object 2 located in the detection area, and also includes photons of ambient light from the detection area.

[0077] Optionally, one of the photosensitive pixels 142 may include a single photoelectric conversion device or multiple photoelectric conversion devices. The photoelectric conversion device is configured to sense the received light signal and convert it into a corresponding electrical signal as the light sensing signal output. The photoelectric conversion device is, for example, a single photon avalanche diode (SPAD), an avalanche photon diode (APD), a silicon photomultiplier (SiPM) with multiple SPADs connected in parallel, and / or other suitable photoelectric conversion elements.

[0078] like Figure 2 As shown, in some embodiments, the acousto-optic deflection module 12 includes a light source module 122, an acousto-optic deflection module 124 and a secondary deflection module 126. The light source module 122 is configured to emit a light beam, and the acousto-optic deflection module 124 is configured to deflect the light beam within a preset first deflection angle range according to the applied sound wave frequency. The light beam emitted by the light source module 122 is deflected along a first direction to a plurality of different preset deflection angles, and the secondary deflection module 126 is configured to deflect the light beam deflected by the acousto-optic deflection module 124 within a preset second deflection angle range. The inner side is further deflected by a preset angle along the first direction to form sensing light beams with different emission directions corresponding to different deflection angles. It should be understood that the first direction here refers to the deflection direction of the light beam, which is different from the emission direction of the light beam. The deflection direction of the light beam can be understood as the direction of the change trend when the emission direction of the light beam is changed.

[0079] like Figure 4As shown, in some embodiments, the light source module 122 includes one or more light-emitting units 1220 and a super lens 1222. The light-emitting unit 1220 is configured to emit a light beam, and the super lens 1222 is arranged on the light-emitting side of the light-emitting unit 1220, and is configured to collimate the light beam emitted by the light-emitting unit 1220. Optionally, the light-emitting unit 1220 can be a light-emitting structure in the form of a vertical cavity surface emitting laser (Vertical Cavity Surface Emitting Laser, referred to as VCSEL, which can also be translated as a vertical resonant cavity surface emitting laser), an edge emitting laser (Edge Emitting Laser, EEL), a light emitting diode (Light Emitting Diode, LED), a laser diode (Laser Diode, LD), a fiber laser, etc. Among them, the edge emitting laser can be a Fabry Perot (Fabry Perot, FP) laser, a distributed feedback (Distribute Feedback, DFB) laser, an electro-absorption modulated laser (Electro-absorption Modulated, EML), etc., and the embodiments of the present application are not limited to this.

[0080] Optionally, the light source module 122 is configured to emit a strip light beam, and the strip light beam can be understood as a light beam whose size along a preset direction is significantly larger than the size in other directions. For the convenience of description, the direction with the largest size can be defined as the length direction of the strip light beam. For example, the shape of the strip light beam can be a slender rectangle, that is, the shape of the light spot of the strip light beam irradiated on the projection surface is a slender rectangle, and the slender rectangle has a pair of long sides and a pair of short sides, and the extension direction of the long side is the length direction of the strip light beam. It should be understood that the shape of the strip light beam is not limited to a slender rectangle, for example, it can also be a long strip with arcs at both ends. If the acousto-optic deflection module 124 deflects the light beam passing through along the first direction, the length direction of the strip light beam emitted by the light source module 122 is parallel to the second direction, and the second direction is perpendicular to the first direction. Optionally, the first direction is a horizontal direction, and the second direction is a vertical direction; or, the first direction is a vertical direction, and the second direction is a horizontal direction.

[0081] Optionally, the multiple light-emitting units 1220 on the light source module 122 can be arranged in a long strip array, and the light beams emitted by each are modulated by the metalens 1222 to form a strip beam that propagates in a collimated manner along the optical axis. It should be understood that the metalens in this application, also known as a supersurface lens or a superstructure lens, is a structural array formed by arranging a large number of sub-wavelength-sized structural units on a two-dimensional plane. The shape, size and macroscopic arrangement of the two-dimensional array of the structural units are designed to achieve modulation of the optical properties of the passing light beam, such as amplitude, phase, wavelength, and polarization state. Since the metalens is a planar optical device and is relatively thin, the light beam passing through the metalens will not cause problems such as spherical aberration.

[0082] Optionally, in some embodiments, the light source module 122 may further include a beam reduction optical device 1223, which may be used to narrow the cross-sectional size of the light beam, that is, the size of the light beam on the cross section perpendicular to the propagation direction of the light beam. The beam reduction optical device 1223 may be disposed in the optical path before the light beam enters the acousto-optic deflection module 124, and is configured to reduce the light beam collimated by the metalens 1222 to a preset size before transmitting it to the acousto-optic deflection module 124. Since the incident area of ​​the acousto-optic deflection module 124 for receiving the light beam has a certain size, in order to allow the light beam incident to the acousto-optic deflection module 124 to enter from the incident area, it is necessary to modulate the light beam to a size matching the incident area before transmitting the light beam to the acousto-optic deflection module 124. It should be understood that in other embodiments, if the size of the light beam emitted by the light emitting unit 1220 after collimation meets the requirements of the incident acousto-optic deflection module 124, the beam reduction optical device 1223 may also be omitted.

[0083] Optionally, in some embodiments, the light source module 122 may further include a linear polarizer 1221. The linear polarizer 1221 is disposed on the optical path before the light beam enters the acousto-optic deflection module 124, and is configured to convert the light beam into linear polarized light with a preset polarization state before entering the acousto-optic deflection module 124. It should be understood that in other embodiments, if other optical elements can convert the light beam into linear polarized light with a preset deflection state before the light beam is transmitted to the acousto-optic deflection module 124, the linear polarizer 1221 may also be omitted.

[0084] exist Figure 4 In the embodiment of the present invention, the beam reduction optical device 1223 is disposed between the metalens 1222 and the linear polarizer 1221. Optionally, in other embodiments, the arrangement order of the beam reduction optical device 1223 and the linear polarizer on the optical path can be interchanged, as long as both are disposed in the optical path before the light beam enters the acousto-optic deflection module 124, and the present application does not impose any specific limitation on this.

[0085] Optionally, in some embodiments, Figure 4-Figure 6As shown, the light source module 122 may also include a polarization beam splitter 1224, a polarization direction adjusting member 1226 and a light guide 1228. The polarization beam splitter 1224 is disposed on the optical path before the light beam enters the acousto-optic deflection module 124, and decomposes the passing light beam into a first polarized light beam and a second polarized light beam, wherein the first polarized light beam has a first polarization direction, and the second polarized light beam has a second polarization direction. The second polarization direction is different from the first polarization direction, for example, the first polarization direction and the second polarization direction are mutually orthogonal. The light guide 1228 is configured to guide the propagation direction of the first polarized light beam or the second polarized light beam, or to guide both the first polarized light beam and the second polarized light beam, so that the first polarized light beam and the second polarized light beam are incident on the acousto-optic deflection module 124 along different optical paths, respectively. The polarization direction adjusting member 1226 is configured to change the polarization direction of the first polarized light beam or the second polarized light beam, so that both enter the acousto-optic deflection module 124 with the same preset polarization direction.

[0086] Specifically, for example, the polarization beam splitter 1224 can be a polarizing prism formed by combining two calcite right-angle prisms along an inclined surface, such as a Glan-Foucault prism. The first polarized light beam propagates to the acousto-optic deflection module 124 along the principal optical axis of the incident direction when the light beam enters the polarization beam splitter 1224 through the combined interface of the polarization beam splitter 1224. The second polarized light beam is reflected by the combined interface of the polarization beam splitter 1224 and deviates from the principal optical axis of the incident direction of the light beam, and then guided by the light guide 1228 to propagate to the acousto-optic deflection module 124 along the side branch optical path deviating from the principal optical axis. It should be noted that the principal optical axis here refers to the direction in which different optical devices in the acousto-optic deflection module 12 are aligned with each other along their respective optical axes, which can be understood as the propagation direction of the light beam emitted by the light emitting unit 1220 that has not changed after being collimated and passing through each optical device in sequence, such as the direction of the zero-order light beam after the light beam passes through the acousto-optic deflection module 124.

[0087] It should be understood that, in some other embodiments, the first polarized light beam and the second polarized light beam decomposed by the polarization beam splitter 1224 may not propagate along the main optical axis where the incident direction of the light beam is located, but instead are guided by the light guide 1228 and propagate along different optical paths to the acousto-optic deflection module 124.

[0088] Optionally, the polarization direction adjusting member 1226 includes a liquid crystal layer, and the polarization direction of the light beam passing through can be changed by adjusting the orientation of the liquid crystal molecules in the liquid crystal layer. Figure 5 As shown, the polarization direction adjusting member 1226 may be disposed on the main optical axis along the direction in which the light beam is incident on the polarization beam splitter 1224, and is configured to change the first polarization direction of the first polarized light beam into a second polarization direction. Figure 6 As shown, the polarization direction adjusting member 1226 may also be disposed on the side branch light path, and configured to change the second polarization direction of the second polarized light beam into the first polarization direction.

[0089] like Figure 5 As shown, the light guide 1228 is, for example, a plurality of reflective optical elements, which guides the second polarized light beam through multiple reflections to enter the acousto-optic deflection module 124 in a direction parallel to the first polarized light beam. Optionally, in some other embodiments, the light guide 1228 may also be an optical fiber.

[0090] Optionally, by reasonably setting the first optical path of the first polarized light beam on the main optical axis and the second optical path of the second polarized light beam on the side branch optical path, the moments when the first polarized light beam and the second polarized light beam after decomposition arrive at the acousto-optic deflection module 124 respectively can have a preset time difference. The time difference between the first polarized light beam and the second polarized light beam obtained by decomposing the same light beam emitted by the corresponding light emitting unit 1220 and arriving at the acousto-optic deflection module 124 respectively can be equal to the emission period of the sensing light beam pulse periodically emitted by the acousto-optic deflection module 12, that is, the time interval between two sensing light beam pulses emitted successively. Therefore, the corresponding light emitting unit 1220 can emit one light beam to obtain two sensing light beam pulses emitted by the acousto-optic deflection module 12.

[0091] It should be understood that by arranging a polarization beam splitter 1224 and a corresponding polarization direction adjusting member 1226 and a light guide 1228 in the optical path of the acousto-optic deflection module 12, not only can the light beam emitted by the light-emitting unit 1220 meet the polarization state requirements of the incident acousto-optic deflection module 124, but the separated second polarized light beam can also be fully utilized for detection, thereby improving the utilization efficiency of the light-emitting power of the acousto-optic deflection module 12.

[0092] like Figure 7 As shown, in some embodiments, the acousto-optic deflection module 124 includes an acousto-optic interaction medium 1241 and an acoustic wave generator 1242. The acousto-optic interaction medium 1241 has a preset light incident surface 1244, a light exit surface 1246, and an acoustic wave incident surface 1248. The acoustic wave generator 1242 is disposed on the acoustic wave incident surface 1248, and is configured to generate an acoustic wave propagating along a preset direction in the acousto-optic interaction medium 1241. The light beam emitted by the light source module 122 enters the acousto-optic interaction medium 1241 from the light incident surface 1244 along a preset incident angle, and the acousto-optic interaction medium 1241 is deflected by the acoustic wave in the propagation direction of the light beam, and the deflected light beam is emitted from the light exit surface 1246.

[0093] The incident angle may be defined as the angle between the incident direction of the light beam and the normal direction of the light incident surface 1244. Optionally, in some embodiments, the material of the acousto-optic interaction medium 1241 is tellurium dioxide. The incident angle is in the range of 2-10 degrees, and there is a preset off-axis angle between the propagation direction of the sound wave in the tellurium dioxide crystal and the lattice direction [1, 1, 0] of the tellurium dioxide crystal. (Not shown in the picture).

[0094] Optionally, in some embodiments, the sound wave generator 1242 may be a piezoelectric transducer, which generates ultrasonic waves to propagate into the acousto-optic interaction medium 1241 to deflect the propagation direction of a light beam passing through the acousto-optic interaction medium 1241 along a preset incident angle.

[0095] It should be understood that the propagation of sound waves in the acousto-optic interaction medium 1241 will cause the refractive index inside the acousto-optic interaction medium 1241 to change. By properly configuring the parameters, the incident light beam can undergo anomalous Bragg diffraction in the acousto-optic interaction medium 1241 under the action of the sound wave, and the propagation direction of the diffracted light beam formed is deflected compared to the propagation direction of the incident light beam. The deflection angle The frequency of the sound wave Into a relational formula: ,in, is the exit angle of the diffracted beam, representing the propagation direction of the diffracted beam, is the incident angle of the incident light beam, representing the propagation direction of the incident light beam, are the wavelengths of the incident and diffracted beams, represents the refractive index of the acousto-optic interaction medium 1241, is the off-axis angle The relevant function value is denoted as The above-mentioned parameters of reasonable configuration include the wavelength, polarization state, incident angle, propagation direction of the incident light beam, the frequency and propagation direction of the sound wave, etc. Therefore, by changing the frequency of the sound wave applied to the acousto-optic interaction medium 1241, the deflection angle of the light beam passing through the acousto-optic interaction medium 1241 can be controlled. When the frequency of the sound wave changes to , the deflection angle of the beam changes accordingly, that is, the scanning angle is .

[0096] It should be noted that the above deflection angle and scanning angle All refer to the angles inside the acousto-optic interaction medium 1241. In practical applications, the angles outside the acousto-optic interaction medium 1241 are used. According to the law of refraction, the angles outside the acousto-optic interaction medium 1241 need to be multiplied by the corresponding refractive index factor. In addition, since it takes time for sound waves to propagate, when the frequency of the sound waves changes from Just started to change to When the acoustic-optic interaction medium 1241 changes from the acoustic wave frequency in the local area close to the acoustic wave generator 1242 to Switch to , the deflection angle of the beam changes from become , the sound wave frequency and the deflection angle of the light beam in the rest of the acousto-optic interaction medium 1241 have not changed yet. If the sound wave propagates through the entire area where the light beam passes through in the acousto-optic interaction medium 1241, that is, the width of the acousto-optic interaction medium 1241, the time required is called the sound wave transit time. After the transit time, the sound wave frequency in the entire acousto-optic interaction medium 1241 changes from becomes , the deflection angle of the beam is completely transformed into Therefore, when the frequency of the sound wave is adjusted to change the deflection angle of the light beam, the deflection time required for the light beam to complete one deflection is It can be considered as equal to the transit time and deflection time of the sound wave The calculation satisfies the following relationship: ,in, is the width of the acousto-optic interaction medium 1241, is the off-axis angle The relevant function value is denoted as .

[0097] The wave vectors between the diffracted light beam, the incident light beam and the sound wave in the acousto-optic interaction medium 1241 need to satisfy the momentum matching condition to form a stable and coherent diffracted light beam in the acousto-optic interaction medium 1241. The incident angle of the light beam that produces anomalous Bragg diffraction will change with the change of the sound wave frequency. However, in practical applications, the incident angle of the light beam in the acousto-optic interaction medium 1241 remains unchanged. As the sound wave frequency changes, the momentum matching condition no longer holds. The farther it deviates from the momentum matching condition, the more the diffraction efficiency decreases. The sound wave frequency range that can effectively complete the anomalous Bragg diffraction is called the Bragg bandwidth. Optionally, in some embodiments, the wavelength of the sensing light beam is 905 nm, the material of the acousto-optic interaction medium 1241 is tellurium dioxide crystal, and the Bragg bandwidth of the corresponding acousto-optic deflection module 124 is about 30 megahertz (MHz), the scanning angle is about 40 milliradians (mrad), that is, about 2.3 degrees, and the deflection time required to complete a beam deflection is about 1.5 MHz. About 10 microseconds ( ), the accuracy of the change of the sound wave frequency is about 30 kilohertz (KHz), and the corresponding accuracy of the change of the scanning angle is about 0.04 mrad. The use of anomalous Bragg diffraction to realize acousto-optic deflection in a tellurium dioxide crystal requires that the incident light beam has a right-handed e-light component. Optionally, if the incident light beam is linearly polarized e-light, the diffracted light beam emitted after the acousto-optic deflection is linearly polarized o-light; if the incident light beam is right-handed circularly polarized light, the diffracted light beam emitted after the acousto-optic deflection is left-handed circularly polarized light. The utilization rate of the emitted diffracted light beam is determined by the ellipticity of the right-handed e-light of the intrinsic mode of the incident light beam, and the ellipticity of the right-handed e-light of the intrinsic mode is determined by the wavelength of the incident light, the incident angle and the material properties of the acousto-optic interaction medium 1241.

[0098] The acousto-optic deflection module 124 can deflect the passing light beam with high precision, but the angle range of the deflected light beam is too small, so a secondary deflection module 126 can be provided on the light-exiting side of the acousto-optic deflection module 124 to further deflect the light beam deflected by the acousto-optic deflection module 124 along the first direction to meet the requirements of high-precision scanning at a large angle. It should be understood that the angle range of the deflected light beam by the secondary deflection module 126 is relatively large, which can at least meet the application requirements of large-angle scanning scenes.

[0099] like Figure 4-Figure 6 As shown, in some embodiments, the secondary deflection module 126 can be a liquid crystal polarization grating (LCPG) module. The LCPG module 126 is disposed on the light-emitting side of the acousto-optic deflection module 124, and is configured to further deflect the light beam deflected by the acousto-optic deflection module 124 at multiple times to form a sensing light beam with different emission directions. The length direction of the strip light beam emitted by the light source module 122 is the second direction, the acousto-optic deflection module 124 deflects the strip light beam along the first direction, and the LCPG module 126 further deflects the strip light beam deflected by the acousto-optic deflection module 124 along the first direction within a larger second deflection angle range. It should be understood that the multiple preset deflection angles of the LCPG module 126 form an arithmetic progression according to the preset angle intervals, and the angle intervals can be regarded as the angle tolerance of the arithmetic progression. The first deflection angle range of the light beam by the acousto-optic deflection module 124 is Thus, the acousto-optic deflection module 124 can fine-tune the deflection angle of the light beam to the left or right with a higher deflection accuracy based on each light beam deflection angle of the LCPG module 126, and such fine-tuning of the light beam deflection angle can cover the angular interval between every two adjacent light beam deflection angles of the LCPG module 126, so that the light beam can be deflected for scanning with a higher deflection accuracy of the acousto-optic deflection module 124 within a larger second deflection angle range.

[0100] like Figure 8 As shown, the LCPG module 126 includes at least one liquid crystal polarization grating (LCPG) sheet 1261. The LCPG sheet 1261 is configured to diffract light beams incident in different polarization states to deflection angles corresponding to different diffraction orders. The LCPG module 126 controls the deflection angle of the LCPG sheet 1261 to the passing light beam by changing the diffraction state of the LCPG sheet 1261 and / or the polarization state of the light beam when it is incident on the LCPG sheet 1261. Optionally, the LCPG module 126 can change the diffraction state of the LCPG sheet 1261 to the passing light beam by applying a voltage to change the liquid crystal orientation in the LCPG sheet 1261. For example, when the incident light beam is circularly polarized light and the phase delay of the LCPG sheet 1261 is When the polarization state of the incident light beam and the phase delay of the LCPG plate 1261 are odd multiples, the diffraction light beam formed after passing through the LCPG plate 1261 can be switched between the deflection angles corresponding to the zeroth order, the positive first order and the negative first order of the grating, and the deflection angle corresponding to each diffraction order is determined by the grating period of the LCPG plate 1261: ,in, is the incident wavelength, is the grating period, m = 1, 0, -1, represent the incident angle and the exit angle of the light beam respectively.

[0101] Optionally, the LCPG module 126 may further include a liquid crystal half-wave plate 1262 to control the polarization state of the light beam incident on the LCPG sheet 1261. By adjusting the liquid crystal half-wave plate 1262 to change the polarization state of the light beam when it is incident on the LCPG sheet 1261 and by applying a voltage to the LCPG sheet 1261 to change the diffraction state of the LCPG sheet 1261, the light beam passing through the LCPG sheet 1261 can be deflected to a deflection angle corresponding to the zero order, the positive first order, and the negative first order. The liquid crystal half-wave plate 1262 and the LCPG sheet 1261 of the LCPG module 126 can be used in multiple cascades. By combining and cascading multiple LCPG sheets 1261 with different grating periods and controlling the voltage applied to the liquid crystal half-wave plate 1262 and the LCPG sheet 1261, the deflection angle range of the light beam and the number of deflection angles of the light beam can be increased.

[0102] Alternatively, if Fig. 9 As shown, in some embodiments, the multiple liquid crystal half-wave plates 1262 and LCPG sheets 1261 of the LCPG module 126 can be cascaded in a binary manner. The LCPG module 126 includes a plurality of LCPG units 1260 arranged in sequence along the emission direction of the light beam, each LCPG unit 1260 includes a liquid crystal half-wave plate 1262 and an LCPG sheet 1261, and the deflection angle of the light beam by the LCPG sheet 1261 increases step by step in the order of being arranged in sequence along the emission direction of the light beam, and the value of the natural number is the serial number of the LCPG unit 1260 minus one. Correspondingly, the deflection angle of the LCPG module 126 to the passing light beam is a multiple of the minimum deflection angle of the LCPG sheet 1261 to the passing light beam, and the value of the multiple is the serial number of the LCPG unit 1260 minus one to the power of two.

[0103] Specifically, if the LCPG module 126 includes M LCPG units 1260, each LCPG unit 1260 includes a liquid crystal half-wave plate 1262 and an LCPG plate 1261. The M LCPG units 1260 are arranged in sequence along the emission direction of the light beam, and the deflection angle of the passing light beam increases step by step in the order of arrangement in a natural number power of two. That is, the first LCPG unit 1260 closest to the light incident side has the smallest deflection angle of the passing light beam, and the last LCPG unit 1260 closest to the light exit side has the largest deflection angle of the passing light beam. Assuming that the deflection angle of the first LCPG unit 1260 to the passing light beam is r, the deflection angles of the passing light beam of the M LCPG units 1260 arranged in sequence along the emission direction of the light beam are respectively Correspondingly, the entire LCPG module 126 including M LCPG units 1260 can deflect the passing light beam by an angle of It can be seen that the beam deflection angle that the LCPG module 126 can provide is a multiple of the minimum deflection angle r of a single LCPG unit 1260 for the passing light beam, and the multiple is a natural number, and the maximum value of the natural number is two to the Mth power minus one, where M is the number of LCPG units 1260 included in the LCPG module 126. The angular interval between adjacent deflection levels is r, that is, the angular intervals between the multiple preset deflection angles of the passing light beam by the LCPG module 126 are distributed in an arithmetic progression, and the angular intervals can be regarded as the angular tolerance of the arithmetic progression, and the deflection accuracy of the passing light beam is r. Therefore, the second deflection angle range of the passing light beam by the LCPG module 126 based on the cascade of binary LCPG units 1260 is and the total number of different deflection angles that can be provided The relational expression is , , wherein r is the minimum deflection angle of the passing light beam among the M LCPG units 1260 , and M is the total number of LCPG units 1260 in the LCPG module 126 .

[0104] It should be understood that, according to the diffraction characteristics of the LCPG sheet 1261, the polarization state of the light beam when incident can be left-handed circularly polarized light or right-handed circularly polarized light, depending on the grating vector direction of the LCPG sheet 1261 and the predefined deflection direction. Circularly polarized light can be generated by linearly polarized light or non-polarized light. If the light beam emitted by the light source module 122 is linearly polarized light, it can be converted into circularly polarized light through a quarter wave plate; if the light emitted by the light source module 122 is non-polarized light or partially polarized light, it can be first converted into linearly polarized light through a polarizer, and then converted into circularly polarized light through a quarter wave plate. Therefore, the light source module 122 may also include a polarizer to adjust the polarization state of the emitted light beam to the corresponding circularly polarized light.

[0105] Alternatively, if Fig.10As shown, in some embodiments, the liquid crystal half-wave plate 1262 and multiple LCPG sheets 1261 of the LCPG module 126 can be cascaded in a quasi-binary manner. The LCPG module 126 includes a liquid crystal half-wave plate 1262 and multiple LCPG sheets 1261 arranged in sequence along the exit direction of the light beam, and the deflection angle of the light beam by the LCPG sheet 1261 increases step by step in the order of sequential arrangement along the exit direction of the light beam, and the difference between the deflection angle of the light beam by one LCPG sheet 1261 and the adjacent previous LCPG sheet 1261 increases step by step in the order of sequential arrangement along the exit direction of the light path in the order of two natural numbers, and the value of the natural number is the serial number of the LCPG sheet 1261 minus one. Correspondingly, the deflection angle of the passing light beam by the LCPG module 126 is a multiple of the minimum deflection angle of the passing light beam by the LCPG sheet 1261 therein, and the value of the multiple is two to the power of the serial number of the LCPG sheet 1261 minus one.

[0106] Specifically, the LCPG module 126 of the quasi-binary cascade includes a liquid crystal half-wave plate 1262 and M LCPG plates 1261. The liquid crystal half-wave plate 1262 is arranged in front of the M LCPG plates 1261 along the exit direction of the light beam, and the M LCPG plates 1261 are arranged in sequence along the exit direction of the light beam and the deflection angle of the passing light beam increases step by step in the order of sequential arrangement. That is, the first LCPG plate 1261 closest to the light incident side has the smallest deflection angle of the passing light beam, and the last LCPG plate 1261 closest to the light exit side has the largest deflection angle of the passing light beam. Assuming that the deflection angle of the first LCPG plate 1261 to the passing light beam is r, the deflection angles of the M LCPG plates 1261 arranged in sequence along the exit direction of the light beam to the passing light beam are respectively: The difference between the deflection angle of the light beam of one LCPG sheet 1261 and the adjacent previous LCPG sheet 1261 is arranged in the order along the emission direction of the light beam: , that is, it increases step by step in the form of a natural number of two, and the value of the natural number is the serial number of the LCPG sheet 1261 minus one. Correspondingly, the entire LCPG module 126 including M LCPG sheets 1261 can deflect the passing light beam by an angle of It can be seen that the beam deflection angle that the LCPG module 126 can provide is a multiple of the minimum deflection angle r of a single LCPG sheet 1261 for the passing light beam, and the multiple is a natural number, the maximum value of the natural number is two to the Mth power minus one, and M is the number of LCPG sheets 1261 included in the LCPG module 126. The angular interval between the preset deflection angles of adjacent levels is r, that is, the angular intervals between the multiple preset deflection angles of the passing light beam by the LCPG module 126 are in an arithmetic progression, and the deflection accuracy of the passing light beam is r, and the angular interval r can be regarded as the angular tolerance of the arithmetic progression. Therefore, the second deflection angle range of the passing light beam by the LCPG module 126 based on the cascade of quasi-binary LCPG sheets 1261 is and the total number of different deflection angles that can be provided The relational expression is: , , wherein r is the minimum deflection angle of the passing light beam among the M LCPG sheets 1261 , and M is the total number of LCPG sheets 1261 in the LCPG module 126 .

[0107] Compared with the binary cascaded LCPG unit 1260, the quasi-binary cascaded liquid crystal half-wave plate 1262 and LCPG plate 1261 can set the desired beam deflection angle by the angle difference of deflecting the light beam in different directions, thereby reducing the required number of liquid crystal half-wave plates 1262 and having a higher beam transmittance.

[0108] Alternatively, if Fig.11 As shown, in some embodiments, the liquid crystal half-wave plate 1262 and the LCPG sheet 1261 of the LCPG module 126 can be cascaded in a three-valued manner. The LCPG module 126 includes a plurality of LCPG units 1260 arranged in sequence along the emission direction of the light beam, each LCPG unit 1260 includes a liquid crystal half-wave plate 1262 and an LCPG sheet 1261, and the deflection angle of the light beam by the LCPG sheet 1261 increases step by step in the order of being arranged in sequence along the emission direction of the light beam in a natural number power of three, and the value of the natural number is the serial number of the LCPG unit 1260 minus one. Correspondingly, the deflection angle of the LCPG module 126 to the passing light beam is a multiple of half of the minimum deflection angle of the LCPG sheet 1261 to the passing light beam, and the value of the multiple is the serial number of the LCPG unit 1260 minus one to the power of three.

[0109] Specifically, if the LCPG module 126 includes M LCPG units 1260, each LCPG unit 1260 includes a liquid crystal half-wave plate 1262 and an LCPG plate 1261. The M LCPG units 1260 are arranged in sequence along the emission direction of the light beam, and the deflection angle of the passing light beam increases step by step in the order of the sequential arrangement in the form of a natural number of three. That is, the first LCPG unit 1260 closest to the light incident side has the smallest deflection angle of the passing light beam, and the last LCPG unit 1260 closest to the light exit side has the largest deflection angle of the passing light beam. Assuming that the deflection angle of the first LCPG unit 1260 to the passing light beam is r, the deflection angles of the passing light beam of the M LCPG units 1260 arranged in sequence along the emission direction of the light beam are respectively Correspondingly, the entire LCPG module 126 including M LCPG units 1260 can deflect the passing light beam by an angle of It can be seen that the beam deflection angle that the LCPG module 126 can provide is a multiple of half of the minimum deflection angle r of a single LCPG unit 1260 for the passing light beam, and the multiple is a natural number, and the maximum value of the natural number is three to the Mth power minus one, where M is the number of LCPG units 1260 included in the LCPG module 126. The angular interval between the preset deflection angles of adjacent levels is r, that is, the angular intervals between the multiple preset deflection angles of the passing light beam by the LCPG module 126 are distributed in an arithmetic progression, and the deflection accuracy of the passing light beam is r, and the angular interval can be regarded as the angular tolerance of the arithmetic progression. Therefore, the second deflection angle range of the passing light beam by the LCPG module 126 based on the cascade of the three-valued LCPG units 1260 is and the total number of different deflection angles that can be provided The relational expression is: , , wherein r is the minimum deflection angle of the passing light beam among the M LCPG units 1260 , and M is the total number of LCPG units 1260 in the LCPG module 126 .

[0110] Compared with the binary cascaded LCPG unit 1260, the ternary cascaded LCPG unit 1260 requires fewer liquid crystal devices under the same beam deflection accuracy and deflection range, so the ternary cascaded LCPG unit 1260 has a higher beam transmittance.

[0111] It should be understood that the LCPG sheet 1261 in the above-mentioned embodiments is an active LCPG sheet 1261 provided with electrodes that can adjust its effect on the passing light beam by whether a voltage is applied. Optionally, in some other embodiments, the LCPG sheet 1261 may also be a passive LCPG sheet 1261 without an electrode. Since the passive LCPG sheet 1261 is always in a diffraction state without applying a voltage, it will deflect the passing light beam to different directions symmetrically distributed compared to the incident direction according to the polarization state of the passing light beam by a preset deflection angle, corresponding to the positive first-order diffraction and negative first-order diffraction of the LCPG sheet 1261 to the passing light beam. The polarization state of the light beam passing through the passive LCPG sheet 1261 can be adjusted by matching a liquid crystal half-wave plate 1262 on the light-entering side of the passive LCPG sheet 1261.

[0112] Alternatively, if Fig.12 As shown, in some embodiments, the LCPG module 126 includes M passive LCPG units 1260, each of which includes a liquid crystal half-wave plate 1262 and a passive LCPG plate 1261. The M passive LCPG units 1260 are arranged in binary cascade, and the M passive LCPG units 1260 are arranged in sequence along the emission direction of the light beam, and the deflection angle of the passing light beam increases step by step in the order of arrangement in a natural number power of two. That is, the first passive LCPG unit 1260 closest to the light incident side has the smallest deflection angle of the passing light beam, and the last passive LCPG unit 1260 closest to the light exit side has the largest deflection angle of the passing light beam. Assuming that the deflection angle of the first passive LCPG unit 1260 to the passing light beam is r, the deflection angles of the passing light beam of the M passive LCPG units 1260 arranged in sequence along the emission direction of the light beam are respectively Correspondingly, the entire LCPG module 126 including M passive LCPG units 1260 can deflect the passing light beam by an angle of It can be seen that the beam deflection angle that the LCPG module 126 can provide is an odd multiple of the minimum deflection angle r of a single LCPG for the passing beam, and the maximum value of the odd number is two to the Mth power minus one, where M is the number of passive LCPG units 1260 included in the LCPG module 126. The angular interval between the preset deflection angles of adjacent levels is 2r, that is, the angular intervals between the multiple preset deflection angles of the passing beam by the LCPG module 126 are distributed in an arithmetic progression, and the deflection accuracy of the passing beam is 2r. The angular interval can be regarded as the angular tolerance of the arithmetic progression. Therefore, the second deflection angle range of the passing beam by the passive LCPG unit 1260 based on the binary cascade is 2r. and the total number of different deflection angles that can be provided The relational expression is: , , wherein r is the minimum deflection angle of the passing light beam among the M passive LCPG units 1260 , and M is the total number of passive LCPG units 1260 in the LCPG module 126 .

[0113] Compared with the above-mentioned active LCPG unit 1260, the passive LCPG unit 1260 does not need to adjust the voltage to change the liquid crystal state of the passive LCPG film 1261 during use. It only needs to change the voltage applied to the liquid crystal half-wave plate 1262 to achieve the corresponding control of the light beam deflection angle, which has the beneficial effects of fast response speed and simple driver program.

[0114] In order to ensure that the liquid crystal molecular material in the LCPG sheet 1261 can work normally, it is necessary to control the temperature of the LCPG module 126 to be within a certain temperature range. Fig.13 As shown, the LCPG module 126 may further include a temperature control unit 1263, which is configured to control the temperature of the LCPG unit 1260 within a preset temperature range. The temperature range of normal operation of the liquid crystal material is 0-70°C. When in a low temperature environment, the temperature control unit 1263 heats up the LCPG unit 1260; when in a high temperature environment, the temperature control unit 1263 cools down the LCPG unit 1260.

[0115] When multiple LCPG units 1260 are cascaded, the influence of the grating vector direction of the LCPG sheet 1261 on the light beam deflection can also be considered. The LCPG sheets 1261 with different grating vector directions will have different deflection directions for light beams with the same polarization state. For example, the LCPG sheet 1261 with a first grating vector direction deflects the incident left-handed circularly polarized light to a deflection angle corresponding to the first diffraction order, while the LCPG sheet 1261 with a second grating vector direction opposite to the first grating vector direction deflects the incident left-handed circularly polarized light to a deflection angle corresponding to the first diffraction order. Therefore, by matching the grating vector directions of the LCPG sheets 1261, a cascade method for deflecting the light beam in different directions can be obtained. If the grating vector directions of two adjacent LCPG sheets 1261 are the same, when a circularly polarized light beam passes through the two LCPG sheets 1261, since the LCPG sheets 1261 will change the polarization state of the passing light beam, the deflection direction of the passing light beam by the latter LCPG sheet 1261 will be opposite to the deflection direction of the light beam by the former LCPG sheet 1261, and the total deflection angle of the light beam after passing through the two LCPG sheets 1261 is the difference between the deflection angles of the two LCPG sheets 1261; if the grating vector directions of the two LCPG sheets 1261 are opposite, when the circularly polarized light passes through the two LCPG sheets 1261, the deflection direction of the light beam by the latter LCPG sheet 1261 is the same as the deflection direction of the light beam by the former LCPG sheet 1261, and the total deflection angle of the light beam after passing through the two LCPG sheets 1261 is the sum of the deflection angles of the two LCPG sheets 1261. Thus, when multiple LCPG sheets 1261 are cascaded, multiple different deflection angles of the light beam can be obtained by setting the grating vector direction of each LCPG sheet 1261, so that the deflection angle of the light beam can be controlled more flexibly in a cascaded manner of multiple LCPG sheets 1261. It should be understood that the grating vector direction of the LCPG sheet 1261 depends on the arrangement direction of the liquid crystal molecules in the LCPG sheet 1261.

[0116] like Figure 4-Figure 6 As shown, in some embodiments, the acousto-optic deflection module 12 may further include a beam adjuster 123. The beam adjuster 123 may be disposed between the acousto-optic deflection module 124 and the LCPG module 126, and is configured to adjust the beam before entering the LCPG module 126.

[0117] Optionally, the beam adjustment member 123 may include a converging optical device for converging the light beam deflected by the acousto-optic deflection module 124. The converging optical device may be, for example, a single converging lens or a lens combination consisting of a plurality of converging lenses. In the case where the divergence angle of the light beam is large after the acousto-optic deflection, it is necessary to appropriately reduce the divergence angle of the light beam through the converging optical device before the light beam enters the LCPG module 126 to improve the directivity of the formed sensing light beam. It should be understood that in some embodiments, if the divergence angle of the light beam after deflection by the acousto-optic deflection module 124 is small, the converging optical device may also be omitted.

[0118] Since the acousto-optic deflection module 124 and the LCPG module 126 both deflect the light beam along the first direction, only one-dimensional scanning of the light beam over the detection range can be achieved. Fig.14 As shown, in some embodiments, the acousto-optic deflection module 12 further includes a diffuser 129. The diffuser 129 is disposed on the light-emitting side of the LCPG module 126, and a microstructure capable of modulating the light beam is formed on the diffuser 129, and is configured to expand the divergence angle of the light beam along the second direction to form a long strip sensing light beam, and the direction in which the sensing light beam has the largest size is defined as its length direction, and the length direction of the long strip sensing light beam is parallel to the second direction, and the second direction is perpendicular to the first direction.

[0119] Optionally, the diffuser 129 is a refractive diffuser, and the microstructure realizes the function of expanding the divergence angle of the sensing light beam along a preset direction by refracting the passing light beam. Optionally, the diffuser 129 may also be a diffractive diffuser, and the microstructure realizes the function of expanding the divergence angle of the sensing light beam along a preset direction by diffracting the passing light beam.

[0120] In order to conveniently describe the scanning method of the long strip sensing light beam, as shown in FIG. Fig.14 As shown, the propagation direction of the zero-order light beam that has not been deflected after passing through the acousto-optic deflection module 124 and the LCPG module 126 is taken as the Y axis, the horizontal direction is the X axis, and the vertical direction is the Z axis. An orthogonal rectangular coordinate system is established, and the horizontal plane is the XOY plane, and the vertical plane is the YOZ plane. Fig.14 In the embodiment of the present invention, the first direction is the horizontal direction, that is, the long strip sensing light beam emitted by the acousto-optic deflection module 12 is deflected along the horizontal direction where the X-axis is located, and the second direction is the vertical direction, that is, the length direction of the long strip sensing light beam formed by the expansion divergence angle of the diffuser 129 is parallel to the vertical direction where the Z-axis is located. The process of the long strip sensing light beam being deflected along the X-axis under the action of the acousto-optic deflection module 124 and the LCPG module 126 can realize two-dimensional scanning in the horizontal direction and the vertical direction. It should be understood that the above coordinate system can also be established in Figure 4-Figure 6It is convenient to describe the propagation of the light beam in the optical path.

[0121] It should be understood that, in some other embodiments, the first direction may also be a vertical direction, and the second direction may also be a horizontal direction. That is, the long strip sensing light beam emitted by the acousto-optic deflection module 12 is deflected along the vertical direction where the Z axis is located, and the length direction of the long strip sensing light beam formed by expanding the divergence angle through the diffuser 129 is parallel to the horizontal direction where the Y axis is located. The long strip sensing light beam can realize two-dimensional scanning in the vertical and horizontal directions during the deflection along the Z axis under the action of the acousto-optic deflection module 124 and the LCPG module 126.

[0122] like Figure 2 As shown, the distance measuring device 10 further includes a control circuit 18, and the control circuit 18 is configured to control the acousto-optic deflection module 12 to emit a sensing light beam to scan the detection range, and control the receiving module 14 to cooperate with the scanning of the sensing light beam to sense the light beam returned from the detection range. Optionally, in some embodiments, the control circuit 18 may include a light source control unit 182, an acousto-optic deflection control unit 184, an LCPG control unit 186, and a sensing control unit 188.

[0123] The light source control unit 182 is configured to control the light emitting unit 1220 to periodically emit sensing beam pulses at a preset frequency. As mentioned above, in order to make the time-correlated single photon counting method used in dToF measurement have mathematical statistical significance, the light source control unit 182 controls the corresponding light emitting unit 1220 to emit multiple sensing beam pulses at a preset frequency within a detection frame, such as dozens, hundreds, thousands, tens of thousands, or even millions, and the time period between two adjacent sensing beam pulses can be defined as an emission period or an emission cycle of the sensing beam pulse.

[0124] The sensing control unit 188 is configured to control the photosensitive pixels 142 to perform sensing in a sensing period corresponding to the emission period of the relevant light emitting unit 1220, so as to count in response to the light signal returned from the detection range. Since the light emitting unit 1220 periodically emits the sensing light beam pulse at a preset frequency, the corresponding photosensitive pixels 142 periodically perform sensing at the same preset frequency as the emission period under the control of the sensing control unit 188. Optionally, the sensing control unit 188 can also control some of the photosensitive pixels 142 to cooperate with the receiving optical device 144 to correspondingly sense the light signals returned from different preset directions.

[0125] The LCPG control unit 186 is configured to control the LCPG module 126 to rotate within a second deflection angle range. The passing light beam is deflected by a preset deflection angle, and the deflected angle is arranged in an arithmetic progression according to a preset angle interval r. Optionally, the LCPG control unit 186 controls the deflection angle of the passing light beam by adjusting the voltage applied to the corresponding LCPG unit 1260 in the LCPG module 126. It should be understood that, as mentioned above, the corresponding relationship between the deflection angle of the passing light beam and the applied voltage signal of the LCPG units 1260 of different cascade modes is different. The LCPG control unit 186 can select the voltage control signal to be applied according to the cascade mode of the LCPG units 1260 adopted by the LCPG module 126 and the angle at which the sensing light beam is currently to be deflected.

[0126] The acoustic-optical deflection control unit 184 is configured to control the acoustic-optical deflection module 124 to deflect in a corresponding first deflection angle range. As mentioned above, the acousto-optic deflection control unit 184 can control the deflection angle of the passing light beam by the acousto-optic deflection module 124 by adjusting the frequency of the sound wave applied to the acousto-optic interaction medium 1241. The acousto-optic deflection module 124 changes the deflection time required for the light beam to be deflected once. It is about 10 microseconds. It should be understood that for each beam deflection angle, the acousto-optic deflection module 12 needs to emit multiple sensing beam pulses to detect the distance information in the direction irradiated by the beam deflection angle, and the corresponding photosensitive pixels 142 on the receiving module 14 work synchronously to sense the light signal returned from this direction. The number of sensing beam pulses emitted by the acousto-optic deflection module 12 along different beam deflection angles may be different. For example, the number of sensing beam pulses emitted along the direction may be set according to the farthest distance detection value that the ranging device 10 needs to meet in the direction irradiated by each beam deflection angle. Similarly, the photosensitive pixels 142 on the receiving module 14 configured to sense the light signal in this direction may set the number of sensing time periods within a detection frame according to the farthest distance detection value that needs to be met in this direction.

[0127] When in use, the LCPG control unit 186 can control the LCPG module 126 to be configured in a preset second deflection angle range. The coarse deflection angle of the inner pair of light beams is arranged in an arithmetic progression according to a preset angle interval r, and the angle interval r is the coarse deflection accuracy of the LCPG module 126. The acousto-optic deflection control unit 184 controls the acousto-optic deflection module 124 to deflect the light beam within a first deflection angle range centered on the deflected coarse deflection angle. The preset sound and light deflection accuracy Fine-tune the beam deflection angle. For each preset deflection angle after the corresponding light beam is deflected by the acousto-optic deflection module 124 and the LCPG module 126, the light source control unit 182 controls the light emitting unit 1220 to periodically emit sensing beam pulses in the direction corresponding to the beam deflection angle according to a preset frequency and number of times, and the sensing control unit 188 controls the corresponding photosensitive pixels 142 to synchronously sense the light signal returned from the direction corresponding to the beam deflection angle, so as to perform three-dimensional detection of the direction corresponding to the beam deflection angle.

[0128] Compared with the deflection of the sensing light beam achieved through mechanical rotation solutions and hybrid solid-state solutions, the present application achieves quasi-continuous deflection of the sensing light beam within a preset deflection angle range through a purely solid-state acousto-optic deflection module 124 and an LCPG module 126, without relying on the rotation and vibration of components, and has the beneficial effects of better reliability and compact size.

[0129] Please also read Figure 2 , Fig.13 and Fig.15In some embodiments, the acousto-optic deflection module 12 periodically emits laser pulses as sensing beams according to a preset frequency, and the laser pulses are formed into sensing beams and projected to the detection range through emitting optical devices such as the acousto-optic deflection module 124, the LCPG module 126, and the diffuser 129, that is, the sensing beam can be a periodic pulse beam with a preset frequency. The acousto-optic deflection module 12 can emit multiple laser pulses in one detection frame, and the time period between the emission moments of two adjacent laser pulses can be defined as an emission period of the laser pulse. The corresponding photosensitive pixel 142 configured to sense the detection area irradiated by the laser pulse has a sensing period corresponding to the emission period. For example, the corresponding photosensitive pixel 142 periodically performs sensing according to the same preset frequency as the emission period, and the sensing period has a start time and an end time consistent with the emission period. At the same time as each laser pulse is emitted, the photosensitive pixel 142 starts to sense the photons returned from the detection range, and the timing unit 152 determines the reception time of the photosensitive pixel 142 sensing the light signal according to the light sensing signal generated by the corresponding photosensitive pixel 142 sensing the photon. The statistical unit 154 performs counting statistics in the corresponding time bins according to the light signal reception time determined by the timing unit 152 in multiple sensing time periods of a detection frame to generate a corresponding statistical histogram. The length of the sensing time period is at least greater than the flight time required for the photon to travel back and forth to the corresponding detection area to meet the farthest distance detection value, so as to ensure that the photons reflected from the farthest distance detection value can be sensed and counted. Optionally, in some embodiments, the length of the sensing time period can be set accordingly according to the farthest distance detection value required by the detection area. For example, the sensing time period length of the photosensitive pixel 142 is positively correlated with the farthest distance detection value that the detection area to be detected is required to meet. For the detection area with a larger farthest distance detection value, the sensing time period of the photosensitive pixel 142 implementing the corresponding detection is longer; for the detection area with a smaller farthest distance detection value, the sensing time period of the photosensitive pixel 142 implementing the corresponding detection is shorter.

[0130] Optionally, in some embodiments, all or part of the functional units in the control circuit 18 and / or the processing circuit 15 may be firmware solidified in the storage medium 30 or computer software code stored in the storage medium 30, and executed by one or more corresponding processors 40 to control related components to implement corresponding functions. The processor 40 is, for example but not limited to, an application processor (AP), a central processing unit (CPU), a microcontroller (MCU), etc. The storage medium 30 includes, but is not limited to, flash memory, electrically erasable programmable read only memory (EEPROM), programmable read only memory (PROM), a hard disk, etc.

[0131] Optionally, in some embodiments, the processor 40 and / or the storage medium 30 may be disposed in the distance measuring device 10, for example, integrated on the same circuit board as the acousto-optic deflection module 12 or the receiving module 14. Optionally, in some other embodiments, the processor 40 and / or the storage medium 30 may also be disposed at other locations of the electronic device 1, for example, on the main circuit board of the electronic device 1.

[0132] Optionally, in some embodiments, part or all of the functional units of the control circuit 18 and / or the processing circuit 15 may also be implemented by hardware, for example, by any one of the following technologies or a combination thereof: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, a dedicated integrated circuit having a suitable combinational logic gate circuit, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It is understandable that the above hardware for implementing the functions of the control circuit 18 and / or the processing circuit 15 may be arranged in the distance measuring device 10. The above hardware for implementing the functions of the control circuit 18 and / or the processing circuit 15 may also be arranged at other locations of the electronic device 1, for example, on the main circuit board of the electronic device 1.

[0133] like Fig.16 As shown, in some embodiments, the distance measuring device 10 is, for example, a laser radar, and the electronic device 1 is, for example, a car. The laser radar can be installed at multiple different positions on the car to detect the distance information of objects within the surrounding range of the car and implement driving control accordingly.

[0134] Compared with laser radars that use mechanical rotation and hybrid solid-state methods to achieve sensing beam scanning, the laser radar provided in the present application uses a purely solid-state acousto-optic deflection module 124 and a secondary deflection module 126 to achieve deflection scanning of the sensing beam. Since it no longer needs to rely on rotating or vibrating parts, it has higher reliability and a more compact structure, is easier to pass strict vehicle regulations, and has less impact on the appearance of the car.

[0135] It should be noted that the technical solution to be protected by the present application may satisfy only one of the above embodiments or multiple embodiments at the same time, that is, an embodiment formed by a combination of one or more of the above embodiments also falls within the protection scope of the present application.

[0136] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0137] It should be understood that the various parts of the embodiments of the present application can be implemented with hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple functional units can be implemented with software or firmware stored in a storage medium and executed by a suitable instruction execution system. For example, if implemented with hardware, as in another embodiment, it can be implemented with any one of the following technologies known in the art or their combination: a discrete logic circuit with a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit with a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0138] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An acousto-optic deflection module based on diffuser beam expansion, characterized in that: The module is configured to emit a sensing light beam for three-dimensional information detection to a detection range, and the acousto-optic deflection module provides the sensing light beam for a laser radar as a distance measuring device provided on a vehicle, and comprises: Light source module, including: one or more light emitting units configured to emit a light beam; and A superlens configured to collimate the light beam emitted by the light emitting unit; an acousto-optic deflection module configured to receive the collimated light beam and deflect the light beam to a plurality of different preset deflection angles within a preset first deflection angle range along a first direction according to an applied acoustic wave frequency; A converging optical device is configured to converge the light beam deflected by the acousto-optic deflection module; a liquid crystal polarization grating module is configured to further deflect the deflected and converged light beam at different preset deflection angles at multiple times to form sensing light beams with different emission directions; and a diffuser, arranged at the light-emitting side of the liquid crystal polarization grating module, the diffuser having a microstructure capable of modulating a light beam, configured to expand the divergence angle of the sensing light beam along the second direction to form a long strip sensing light beam, the direction in which the sensing light beam has a maximum size is defined as its length direction, the length direction of the long strip sensing light beam is parallel to the second direction, and the second direction and the first direction are arranged perpendicular to each other; The light source module further includes a polarization beam splitter, a polarization direction adjusting member and a light guide member. The polarization beam splitter is arranged on the optical path before the light beam enters the acousto-optic deflection module. The polarization beam splitter decomposes the passing light beam into a first polarization beam and a second polarization beam. The first polarization beam has a first polarization direction, and the second polarization beam has a second polarization direction different from the first polarization direction. The light guide member is configured to guide the propagation direction of the first polarization beam or the second polarization beam, or guide the propagation directions of both the first polarization beam and the second polarization beam, so that the first polarization beam and the second polarization beam are respectively incident on the acousto-optic deflection module along different optical paths. The polarization direction adjusting member is configured to change the polarization direction of the first polarization beam or the second polarization beam, so that both enter the acousto-optic deflection module with the same preset polarization direction. The moments when the decomposed first polarization beam and the second polarization beam respectively arrive at the acousto-optic deflection module have a preset time difference. The acousto-optic deflection emission module periodically emits sensing beam pulses according to a preset frequency. The time difference is equal to the time interval between two sensing beam pulses emitted successively. The length of the time interval is at least greater than the flight time required for the photon to travel back and forth to the corresponding detection area to meet the maximum distance detection value.

2. The acousto-optic deflection module according to claim 1, characterized in that: The first direction is a horizontal direction, and the second direction is a vertical direction; or The first direction is a vertical direction, and the second direction is a horizontal direction.

3. The acousto-optic deflection module according to claim 1, characterized in that: The diffuser is a refractive diffuser, and the microstructure realizes the function of expanding the divergence angle of the sensing light beam along a preset direction by refracting the passing light beam.

4. The acousto-optic deflection module according to claim 1, characterized in that: The diffuser is a diffraction diffuser, and the microstructure realizes the function of expanding the divergence angle of the sensing light beam along a preset direction by diffracting the passing light beam.

5. The acousto-optic deflection module according to claim 1, characterized in that: The liquid crystal polarization grating module deflects a plurality of preset deflection angles of the light beam to form an arithmetic progression according to a preset first angle interval, and the first deflection angle range is greater than or equal to the first angle interval.

6. The acousto-optic deflection module according to claim 1, characterized in that: The liquid crystal polarization grating module comprises a plurality of liquid crystal polarization grating units sequentially arranged along the exit direction of the light beam, each liquid crystal polarization grating unit comprises a liquid crystal half-wave plate and a liquid crystal polarization grating plate, the deflection angle of the passing light beam by the liquid crystal polarization grating plates increases step by step in the order of being sequentially arranged along the exit direction of the light beam in the form of a natural number of two, the value of the natural number is the sequence number of the liquid crystal polarization grating plates minus one, and the liquid crystal polarization grating module controls the preset deflection angle of the light beam after passing through the liquid crystal polarization grating plates by changing the diffraction state of the light beam passing through the liquid crystal polarization grating plates.

7. The acousto-optic deflection module according to claim 1, characterized in that: The liquid crystal polarization grating module comprises a plurality of liquid crystal polarization grating units sequentially arranged along the emitting direction of the light beam, each liquid crystal polarization grating unit comprises a liquid crystal half-wave plate and a liquid crystal polarization grating plate, the deflection angle of the passing light beam by the liquid crystal polarization grating plates increases step by step in the order of being sequentially arranged along the emitting direction of the light beam in the form of a natural number to the power of three, the value of the natural number being the sequence number of the liquid crystal polarization grating plates minus one, and the liquid crystal polarization grating module controls the preset deflection angle of the light beam after passing through the liquid crystal polarization grating plates by changing the diffraction state of the light beam passing through the liquid crystal polarization grating plates.

8. The acousto-optic deflection module according to claim 1, characterized in that: The liquid crystal polarization grating module comprises a liquid crystal half-wave plate and a plurality of liquid crystal polarization grating plates which are sequentially arranged along the emitting direction of the light beam. The deflection angle of the light beam by the liquid crystal polarization grating plates gradually increases in the order in which they are sequentially arranged along the emitting direction of the light beam. The difference in the deflection angle of the light beam by one liquid crystal polarization grating plate and the adjacent previous liquid crystal polarization grating plate increases step by step in the order in which they are sequentially arranged along the emitting direction of the light beam in the form of a natural number to the power of two. The value of the natural number is the sequence number of the liquid crystal polarization grating plate minus one. The liquid crystal polarization grating module controls the preset deflection angle of the light beam after passing through the liquid crystal polarization grating plate by changing the diffraction state of the light beam passing through the liquid crystal polarization grating plate.

9. The acousto-optic deflection module according to claim 1, characterized in that: The light source module further includes a linear polarizer, which is disposed on the optical path of the light beam before it enters the acousto-optic deflection module and is configured to convert the light beam into linear polarized light with a preset polarization state before it enters the acousto-optic deflection module.

10. The acousto-optic deflection module according to claim 1, characterized in that: The light source module further includes a beam reduction optical device, which is configured to reduce the light beam collimated by the superlens to a preset size before transmitting it to the acousto-optic deflection module.

11. The acousto-optic deflection module according to claim 1, characterized in that: The first polarized light beam is transmitted through the polarization beam splitter to the acousto-optic deflection module along the main optical axis where the incident direction of the light beam is when it enters the polarization beam splitter. The polarization direction adjusting member is arranged on the main optical axis and is configured to change the first polarization direction of the first polarized light beam to the second polarization direction.

12. The acousto-optic deflection module according to claim 1, characterized in that: After passing through the polarization beam splitter, the second polarized light beam propagates to the acousto-optic deflection module along a side branch light path that deviates from the main optical axis where the incident direction of the light beam is located when it is incident on the polarization beam splitter. The polarization direction adjusting component is arranged on the side branch light path and is configured to change the second polarization direction of the second polarized light beam into the first polarization direction.

13. The acousto-optic deflection module according to claim 11 or 12, characterized in that: The polarization direction adjusting member includes a liquid crystal layer, and is configured to change the polarization direction of the passing light beam by adjusting the orientation of liquid crystal molecules in the liquid crystal layer.

14. The acousto-optic deflection module according to claim 1, characterized in that: After being guided by the light guide, the second polarized light beam enters the acousto-optic deflection module in a direction parallel to the first polarized light beam, and the incident points of the first polarized light beam and the second polarized light beam on the acousto-optic deflection module are both located within a preset incident area on the acousto-optic deflection module.

15. A distance measuring device, characterized in that: The device is configured to detect three-dimensional information of an object within a preset detection range, and includes an acousto-optic deflection module as described in any one of claims 1 to 14. The ranging device also includes a receiving module and a processing module. The receiving module is configured to sense light signals from within the detection range and output corresponding light sensing signals. The processing module is configured to analyze and process the light sensing signals to obtain three-dimensional information of the object within the detection range.

16. An electronic device, characterized in that: The electronic device comprises the distance measuring device as claimed in claim 15, and further comprises an application module, wherein the application module is configured to implement corresponding functions according to the detection result of the distance measuring device.

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