Polarization beam splitter-based light beam deflection module, detection device and electronic equipment

Abstract

The application provides a polarization beam splitter-based light beam deflection module for emitting a sensing light beam to a detection range, comprising a light source module, a polarization beam splitter, a light guide, a polarization direction adjusting member and an acousto-optic deflection module. The light source module emits a light beam. The polarization beam splitter decomposes the light beam into first and second polarized light beams with different polarization directions. The light guide is configured to guide the propagation direction of the first or second polarized light beam or the propagation direction of both the first and second polarized light beams, so that the two respectively enter the acousto-optic deflection module along different light paths. The polarization direction adjusting member is used to change the original polarization direction of the first or second polarized light beam, so that the two enter the acousto-optic deflection module with the same polarization direction. The acousto-optic deflection module is used to deflect the first and second polarized light beams by a plurality of different deflection angles in a first direction within a first deflection angle range according to the applied acoustic wave frequency. The application also provides a detection device and an electronic equipment.

Description

Technical Field

[0001] This application belongs to the field of optoelectronic detection, and in particular relates to a beam deflection module, detection device and electronic equipment based on a polarization beam splitter. Background Technology

[0002] Time-of-Flight (ToF) measurement works by calculating three-dimensional information such as the distance to an object based on the time it takes for the detected light reflected from the object in the measurement scene to travel. Due to its advantages such as long sensing distance, high accuracy, and low power consumption, ToF measurement is widely used in consumer electronics, autonomous driving, AR / VR, and other fields.

[0003] Distance measurement devices using the Time-of-Flight (ToF) principle have limited field of view, requiring continuous scanning by changing the emission direction of the detection light to achieve a wider detection range. Currently, one method for changing the emission direction involves using a mechanical rotating structure. However, this method often requires multiple discrete components assembled into a mechanical rotating structure, resulting in high complexity in the debugging and assembly of the transmitting / receiving optical paths. The mechanical rotating structure is also prone to damage and inaccuracy, and its large size affects the appearance of the terminal equipment using it. Another method is a hybrid solid-state solution, which primarily uses a vibrating component to drive the optical component to change the emission direction of the detection light. While the hybrid solid-state solution significantly reduces cost and size compared to the mechanical rotating solution, the system's reliability remains low due to the vulnerability of the vibrating component, limiting the application scenarios of the detection device. Summary of the Invention

[0004] In view of this, this application provides a beam deflection module, detection device and electronic device based on a polarization beam splitter that can improve the problems of the prior art.

[0005] In a first aspect, this application provides a beam deflection module based on a polarization beam splitter, configured to emit a sensing beam for three-dimensional information detection into a detection range. The module includes a light source module, a polarization beam splitter, and an acousto-optic deflection module arranged sequentially along the beam propagation direction.

[0006] The light source module is configured to emit a light beam;

[0007] The polarization beam splitter is disposed in the optical path before the light beam enters the acousto-optic deflection module, and is configured to decompose the passing light beam into a first polarized beam with a first polarization direction and a second polarized beam with a second polarization direction, wherein the first polarization direction is different from the second polarization direction.

[0008] The beam deflection module further includes a light guide and a polarization direction adjustment component. The light guide is configured to guide the propagation direction of the first polarized beam or the second polarized beam, or to guide both the first polarized beam and the second polarized beam, so that the first polarized beam and the second polarized beam are incident on the acousto-optic deflection module along different optical paths. The polarization direction adjustment component is configured to change the first polarization direction of the first polarized beam or the second polarization direction of the second polarized beam, so that both enter the acousto-optic deflection module with the same preset polarization direction.

[0009] The acousto-optic deflection module is configured to deflect the first polarized beam and the second polarized beam at multiple different preset deflection angles within a preset first deflection angle range and along a preset first direction, according to the applied acoustic wave frequency.

[0010] Secondly, this application provides a detection device configured to perform distance detection on an object located within a preset detection range. The detection device includes a receiving module, a processing circuit, and a beam deflection module as described above. The receiving module is configured to sense light signals from within the detection range and output corresponding light-sensing signals, and the processing circuit is configured to analyze and process the light-sensing signals to obtain three-dimensional information of the object within the detection range.

[0011] Thirdly, this application provides an electronic device, including an application module and a detection device as described above. The application module is configured to perform corresponding functions based on the detection results of the detection device.

[0012] The beneficial effects of this application are:

[0013] Compared to mechanical rotation schemes and hybrid solid-state schemes for deflecting the sensing beam, this application achieves continuous deflection of the sensing beam within a preset deflection angle range using a purely solid-state acousto-optic deflection module. This eliminates the need for component rotation and vibration, resulting in better reliability and a more compact size. Attached Figure Description

[0014] The features and advantages of the present invention will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0015] Figure 1 This is a schematic diagram of the functional modules of an electronic device provided in an embodiment of this application;

[0016] Figure 2 for Figure 1 A functional module diagram of one embodiment of the detection device described herein;

[0017] Figure 3 for Figure 2A schematic diagram of the statistical histogram obtained by the processing circuit described above;

[0018] Figure 4 for Figure 2 A partial optical path diagram of an embodiment of the beam deflection module described herein;

[0019] Figure 5 for Figure 2 A partial optical path diagram of another embodiment of the beam deflection module described herein;

[0020] Figure 6 for Figure 2 A schematic diagram of an embodiment of the beam deflection module described herein;

[0021] Figure 7 for Figure 2 A schematic diagram of the acousto-optic deflection module described above;

[0022] Figure 8 for Figures 4-5 The secondary deflection module described herein is a schematic diagram of the superlens structure;

[0023] Figure 9 for Figures 4-5 The secondary deflection module described herein is a schematic diagram of the optical path of the projection optical system;

[0024] Figure 10 for Figures 4-5 The secondary deflection module described herein is a schematic diagram of the optical path of another embodiment of the projection optical system;

[0025] Figure 11 for Figures 4-5 The secondary deflection module described herein is a schematic diagram of the LCPG module.

[0026] Figure 12 This is a schematic diagram of the structure of a binary cascaded LCPG module provided in an embodiment of this application;

[0027] Figure 13 This is a schematic diagram of the structure of a binary cascaded LCPG module provided in an embodiment of this application;

[0028] Figure 14 A schematic diagram of the structure of a ternary cascaded LCPG module provided in an embodiment of this application;

[0029] Figure 15 A schematic diagram of the structure of a binary cascaded passive LCPG unit provided in an embodiment of this application;

[0030] Figure 16 for Figure 2 A schematic diagram of an embodiment of the beam deflection module described herein;

[0031] Figure 17 for Figure 2 A partial optical path diagram of another embodiment of the beam deflection module described herein;

[0032] Figure 18 for Figures 16-17 The beam expansion module described herein is a schematic diagram of an embodiment of a cylindrical beam expander lens;

[0033] Figure 19 for Figure 18 Side view optical path diagram of the cylindrical beam expander lens described above;

[0034] Figure 20 for Figures 16-17 The beam expansion module described herein is a schematic diagram of another embodiment of a cylindrical beam expander lens;

[0035] Figure 21 for Figure 20 Side view optical path diagram of the cylindrical beam expander lens described above;

[0036] Figure 22 for Figures 16-17 A schematic diagram of another embodiment of the beam extension module described herein;

[0037] Figure 23 A schematic diagram of another embodiment of the beam deflection module described herein;

[0038] Figure 24 A signal timing diagram of the detection device provided in an embodiment of this application during detection;

[0039] Figure 25 The detection device provided in one embodiment of this application is a structural schematic diagram of an automotive lidar. Detailed Implementation

[0040] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote 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 this application, and should not be construed as limiting this application. In the description of this application, it should be understood that the terms "first" and "second" are used for description only and should not be construed as indicating or implying relative importance or implicitly specifying the number or order of the indicated technical features. Thus, technical features defined with "first" and "second" may explicitly or implicitly include one or more of the stated technical features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integrated connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, only specific examples of components and settings are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or reference letters may be repeated in different examples; such repetition is for the purpose of simplifying and clearly describing this application and does not in itself indicate a specific relationship between the various embodiments and / or settings discussed. Moreover, the various specific processes and materials described below are merely examples for implementing the technical solutions of this application; however, those skilled in the art should recognize that the technical solutions of this application can also be implemented using other processes and / or other materials not described below.

[0043] Furthermore, the described features and structures can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced even without one or more of the specific details described, or with other structures, components, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring the focus of this application.

[0044] This application provides a beam deflection module based on a polarization beam splitter, configured to emit a sensing beam for three-dimensional information detection into a detection range. It includes a light source module, a polarization beam splitter, and an acousto-optic deflection module arranged sequentially along the beam propagation direction. The light source module is configured to emit the beam. The polarization beam splitter is disposed on the optical path before the beam enters the acousto-optic deflection module and is configured to decompose the passing beam into a first polarized beam with a first polarization direction and a second polarized beam with a second polarization direction, the first polarization direction being different from the second polarization direction. The beam deflection module further includes a light guide and a polarization direction adjustment component. The light guide is configured to guide the propagation direction of either the first polarized beam or the second polarized beam, or both, so that the first polarized beam and the second polarized beam are incident on the acousto-optic deflection module along different optical paths. The polarization direction adjustment component is configured to change the first polarization direction of the first polarized beam or the second polarization direction of the second polarized beam, so that both enter the acousto-optic deflection module with the same preset polarization direction. The acousto-optic deflection module is configured to deflect the first polarized beam and the second polarized beam at multiple different preset deflection angles within a preset first deflection angle range and along a preset first direction, according to the applied acoustic wave frequency.

[0045] Optionally, in some embodiments, the light beam emitted by the light source module is a bar-shaped collimated beam, and the direction in which the bar-shaped collimated beam has the largest size is defined as its length direction. The length direction of the bar-shaped collimated beam is parallel to a preset second direction, and the second direction is perpendicular to the first direction.

[0046] 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.

[0047] Optionally, in some embodiments, a superlens is further included, configured to further deflect and shape the beam deflected by the acousto-optic deflection module along the first direction by a preset angle, so as to form sensing beams with different exit directions corresponding to different deflection angles.

[0048] Optionally, in some embodiments, the superlens extends the divergence angle of the transmitted light beam along a second direction to form an elongated sensing light beam, the second direction being perpendicular to the first direction.

[0049] Optionally, in some embodiments, the superlens extends the divergence angle of the transmitted light beam along the first direction, such that the respective sensing beams formed at different deflection angles partially overlap each other in their respective far-field irradiated regions along the first direction.

[0050] Optionally, in some embodiments, a projection optical system is further included, configured to project the light beam deflected by the acousto-optic deflection module along a preset emission direction corresponding to the beam deflection angle within the detection range to form the sensing beam; wherein the light beam deflected by the acousto-optic deflection module passes through a corresponding area on the focal plane of the projection optical system and is then projected by the projection optical system, and the corresponding area moves on the focal plane as the beam deflection angle changes.

[0051] Optionally, in some embodiments, the focal plane is located between the acousto-optic deflection module and the projection optical system, and the corresponding area on the focal plane serves as a secondary light source area to emit the sensing beam.

[0052] Optionally, in some embodiments, a liquid crystal polarization grating module is further included, configured to further deflect the light beam deflected by the acousto-optic deflection module by a corresponding preset deflection angle at multiple times to form the sensing light beam.

[0053] Optionally, in some embodiments, the liquid crystal polarization grating module deflects multiple preset deflection angles of the beam in an arithmetic sequence according to a preset first angular interval, wherein the range of the first deflection angle is greater than or equal to the first angular interval.

[0054] Optionally, in some embodiments, a beam expansion module is further included, disposed on the light-emitting side of the projection optical system or the liquid crystal polarization grating module. The beam expansion module is configured to expand the sensing beam along a divergence angle in a second direction to form an elongated sensing beam, wherein the second direction is perpendicular to the first direction.

[0055] Optionally, in some embodiments, the beam expansion module includes a refractive diffuser with a microstructure formed on it that can modulate the beam. The microstructure expands the sensing beam divergence angle along a preset direction by refracting the beam.

[0056] Optionally, in some embodiments, the beam expansion module includes a diffraction diffuser with a microstructure formed on it that can modulate the beam. The microstructure expands the sensing beam divergence angle along a preset direction by diffracting the beam.

[0057] Optionally, in some embodiments, the beam expansion module includes a cylindrical beam expander lens, the cylindrical beam expander lens including an optical surface bent along the second direction to expand the divergence angle of the sensed beam along the second direction.

[0058] Optionally, in some embodiments, the beam expansion module further includes a collimating lens and an emitting lens. The collimating lens is disposed on the incident side of the cylindrical beam expander and is configured to collimate the sensing beam projected by the projection optical system along the optical axis before it enters the cylindrical beam expander. The emitting lens is disposed on the exit side of the cylindrical beam expander and is configured to re-emit the sensing beam, whose divergence angle has been expanded by the cylindrical beam expander, along the direction in which the sensing beam was originally projected from the projection optical system.

[0059] Optionally, in some embodiments, the light source module further includes a beam-shrinking optics device configured to reduce the light beam to a preset size before transmitting it to the acousto-optic deflection module.

[0060] Optionally, in some embodiments, the first polarized beam and the second polarized beam, after being decomposed, arrive at the acousto-optic deflection module at a preset time difference.

[0061] Optionally, in some embodiments, when the first polarized beam is incident on the polarization beam splitter, the principal optical axis containing the incident direction propagates through the polarization beam splitter to the acousto-optic deflection module. The polarization direction adjustment element is disposed on the principal optical axis and configured to change the first polarization direction of the first polarized beam to the second polarization direction.

[0062] Optionally, in some embodiments, after the second polarized beam passes through the polarization beam splitter, it propagates along a side path of the main optical axis that deviates from the incident direction of the beam when it enters the polarization beam splitter to the acousto-optic deflection module. The polarization direction adjustment element is disposed on the side path and is configured to change the second polarization direction of the second polarized beam to the first polarization direction.

[0063] Optionally, in some embodiments, the polarization direction adjustment element includes a liquid crystal layer configured to change the polarization direction of the passing light beam by adjusting the orientation of liquid crystal molecules within the liquid crystal layer.

[0064] Optionally, in some embodiments, the second polarized beam is guided by the light guide and enters the acousto-optic deflection module in a direction parallel to the first polarized beam, and the incident points of the first polarized beam and the second polarized beam on the acousto-optic deflection module are both located within a preset incident area on the acousto-optic deflection module.

[0065] Embodiments of this application also provide a detection device configured to perform three-dimensional information detection on objects located within a preset detection range. The device includes the beam deflection module described above, a receiving module, and a processing circuit. The detection device further 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 objects within the detection range.

[0066] Embodiments of this application also provide an electronic device including the aforementioned detection device. The electronic device performs corresponding functions based on the three-dimensional information obtained by the detection device. Examples of such electronic devices include: mobile phones, automobiles, robots, access control / monitoring systems, smart locks, and drones. The three-dimensional information includes, for example, proximity information, depth information, distance information, and coordinate information of objects within the detection range. This three-dimensional information can be used, for example, in fields such as 3D modeling, facial recognition, autonomous driving, machine vision, monitoring, drone control, augmented reality (AR) / virtual reality (VR), simultaneous localization and mapping (SLAM), and object proximity detection; this application does not limit its application to these fields.

[0067] The detection device can be, for example, a lidar (LiDAR), used to obtain three-dimensional information of objects within the detection range. LiDAR is applied in fields such as autonomous vehicles, autonomous aircraft, 3D printing, VR, AR, and service robots. Taking an autonomous vehicle as an example, a lidar is installed in the vehicle. The lidar scans the surrounding environment by rapidly and repeatedly emitting laser beams to obtain point cloud data reflecting the shape, position, and movement of one or more objects in the environment. Specifically, the lidar emits a laser beam into the surrounding environment and receives the echo beams reflected back by various objects in the environment. By calculating the time delay (time of flight) between the emission time of the laser beam and the return time of the echo beams, the distance / depth information of each object is determined. Simultaneously, the lidar can also determine the angular information describing the orientation of the laser beam's detection range. Combining the distance / depth information of each object with the angular information of the laser beam generates a three-dimensional map including all objects in the scanned surrounding environment. This three-dimensional map can guide the autonomous driving of the vehicle.

[0068] Hereinafter, embodiments of the detection device applied to electronic devices will be described in detail with reference to the accompanying drawings.

[0069] Figure 1This is a schematic diagram of the functional modules of the detection device provided in this application embodiment applied to an electronic device. Figure 2 This is a schematic diagram of the functional modules of the detection device provided in the embodiments of this application.

[0070] Reference Figure 1 and Figure 2 The electronic device 1 includes a detection device 10. The detection device 10 can detect objects 2 within a detection range to obtain three-dimensional information about the objects 2. The detection range can be defined as the three-dimensional spatial range within which the detection device 10 can effectively perform three-dimensional information detection, or it can be referred to as the field of view of the detection device 10. The three-dimensional information includes, but is not limited to, one or more of the following: proximity information of the object 2, depth information of the surface of the object 2, distance information of the object 2, and spatial coordinate information of the object 2.

[0071] The electronic device 1 may include an application module 20, which is configured to perform preset operations or implement corresponding functions based on the detection results of the detection device 10. For example, but not limited to: determining whether an object 2 is within a preset detection range in front of the electronic device 1 based on its proximity information; or controlling the movement of the electronic device 1 to avoid obstacles based on the distance information of the object 2; or realizing 3D modeling, face recognition, machine vision, etc., based on the depth information of the object 2's surface. The electronic device 1 may also include a storage medium 30, which supports the storage needs of the electronic device 1 and / or the detection device 10 during operation. The electronic device 1 may also include a processor 40, which supports the data processing needs of the electronic device 1 and / or the detection device 10 during operation.

[0072] Optionally, in some embodiments, the detection device 10 may be, for example, a dToF measurement device for three-dimensional information sensing based on the direct time of flight (dToF) principle. The dToF measurement device can emit a sensing beam within the detection range and receive the sensing beam reflected back from the 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 can be obtained by calculating half the distance traveled by the sensing beam within the flight time t. Where c is the speed of light.

[0073] Alternatively, in some other embodiments, the detection device 10 may also be an iToF measurement device that uses the indirect time-of-flight (iToF) measurement principle to sense three-dimensional information. The iToF measurement device obtains the three-dimensional information of the object 2 by comparing the phase difference between when the sensing beam is emitted and when it is reflected back and received.

[0074] In the embodiments described below, the detection device 10 is mainly used as a dToF measuring device for illustration.

[0075] Optionally, such as Figure 2 As shown, the detection device 10 includes a beam deflection module 12, a receiving module 14, and a processing circuit 15. The beam deflection module 12 is configured to emit a sensing beam into a detection range to detect the three-dimensional information of an object 2 within that range. A portion of the sensing beam is reflected back by the object 2, carrying the three-dimensional information of the object 2. A portion of the reflected sensing beam 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 light signals from the detection range and output corresponding photosensitive signals. By analyzing these photosensitive signals, the three-dimensional information of the object 2 within the detection range can be detected. It is understood that the light signals sensed by the receiving module 14 can be photons, including photons from the sensing beam reflected back from the object 2 within the detection range and photons from ambient light within the detection range. The processing circuit 15 is configured to analyze and process the photosensitive signals to obtain the moment the sensing beam is sensed by the receiving module 14, and to obtain the three-dimensional information of the object 2 based on the time difference between the emission time and the time of reflection of the sensing beam.

[0076] The processing circuit 15 may be disposed on the detection 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.

[0077] Optionally, the sensing beam can be a laser pulse with a preset frequency. The beam deflection module 12 is configured to periodically emit the laser pulse as a sensing beam at a preset frequency within a detection frame.

[0078] Optionally, the sensing beam is, for example, visible light, infrared light or near-infrared light, with a wavelength range of, for example, 390 nm-780 nm, 700 nm-1400 nm, 800 nm-1000 nm, 900 nm-1600 nm.

[0079] Please refer to the following: Figure 2 and Figure 3 , Figure 3 for Figure 2 A schematic diagram of the statistical histogram obtained by the processing circuit 15 described above. Optionally, in some embodiments, the processing circuit 15 may include a timing unit 152, a statistics unit 154, a time-of-flight acquisition unit 156, and a three-dimensional information acquisition unit 158.

[0080] The timing unit 152 is configured to determine the reception time of the light signal sensed by the receiving module 14. During the detection process, the detection device 10 emits multiple sensing beams through the beam deflection module 12. The timing unit 152 starts timing each time the beam deflection module 12 emits a sensing beam to record the reception time of the light signal sensed by the receiving module 14 between two adjacent sensing beam emissions. During this period, the receiving module 14 outputs a corresponding photosensitive signal for each light signal received. The timing unit 152 records the reception time of the sensed light signal based on the photosensitive signal output by the receiving module 14 and counts it in a time bin corresponding to the reception time, forming a corresponding light signal count. The time bin is the smallest time unit Δt used by the timing unit 152 to record the moment the photosensitive signal is generated, reflecting the accuracy of the timing unit 152's time recording of the light signal; a finer time bin indicates higher accuracy. Optionally, the timing unit 152 can implement the timing function using a Time-to-Digital Converter (TDC) 1522. The TDC1522 can be connected to a corresponding photosensitive pixel 142 and is configured to record the reception time of the sensed light signal based on the light sensing signal generated by the corresponding photosensitive pixel 142. For example, the TDC1522 is synchronously triggered to start timing each time a sense beam is emitted, and subsequently stops timing in response to the light sensing signal generated by the corresponding photosensitive pixel 142, and the time period of timing is taken as the reception time of the corresponding light signal that triggered the light sensing signal.

[0081] Optionally, in some embodiments, the timing unit 152 may include a counting memory 1524, which has counting storage space allocated according to the time bins. Each time the TDC 1522 records the reception time of an optical signal, it increments by one in the counting storage space of the corresponding time bin.

[0082] The statistical unit 154 is configured to count the cumulative optical signals within each time slot to obtain a statistical histogram reflecting the distribution of the number of optical signals sensed by the receiving module 14 over time. For example, Figure 3 As shown, the horizontal axis of the statistical histogram represents the timestamp of each corresponding time bin, and the vertical axis represents the cumulative optical signal count value within 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 statistically analyze the optical signal counts within each time bin to generate a statistical histogram. It should be understood that the statistical unit 154 performs statistical analysis on the cumulative optical signal counts corresponding to multiple transmissions of the sensing beam within a detection frame. To ensure the counts have mathematical statistical significance, the number of transmissions of the sensing beam within a detection frame can be as many as hundreds, thousands, tens of thousands, hundreds of thousands, or even millions.

[0083] During the sensing process, a large number of ambient light photons are also sensed by the receiving module 14, generating corresponding optical signal counts. The probability of these ambient light photons being sensed and leaving a count in each time slot tends to be the same, forming a noise level within the detection range. In scenarios with high ambient light intensity, the average level of the measured noise level is relatively high; in scenarios with low ambient light intensity, the average level of the measured noise level is relatively low. Based on this, the optical signal count generated by the sensing beam reflected from object 2 is superimposed on the noise level, making the optical signal count in the time slot corresponding to the moment the sensing beam is sensed significantly higher than the optical signal count in other time slots, thus forming a prominent signal peak. It is understood that the height of the signal peak count is affected by factors such as the optical power of the sensing beam, the reflectivity of object 2, and the detection range of the detection device 10; the width of the signal peak is affected by factors such as the pulse width of the emitted sensing beam, the photoelectric conversion element of the receiving module 14, and the timing jitter of the TDC1522. Therefore, the time-of-flight acquisition unit 156 can obtain the flight time of the relevant sensing beam reflected back by the object 2 based on the time difference between the timestamp t1 of the time bin corresponding to the peak value of the signal peak and the emission time t0 of the relevant sensing beam that generated the signal peak. The three-dimensional information acquisition unit 158 ​​can be configured to obtain three-dimensional information between the object 2 reflecting the sensing beam and the detection device 10 based on the flight time of the sensing beam determined by the statistical histogram, such as the distance between the object 2 and the detection device 10 within the detection range.

[0084] It should be understood that the beam deflection module 12 and the receiving module 14 are arranged side by side, with the light-emitting surface of the beam deflection module 12 and the light-incident surface of the receiving module 14 both facing the same side of the detection device 10. The distance between the beam deflection module 12 and the receiving module 14 can range from, for example, 2 mm to 20 mm. Since the beam deflection module 12 and the receiving module 14 are relatively close, although the emission path of the sensing beam from the beam deflection module 12 to the object 2 and the return path after reflection from the object 2 to the receiving module 14 are not exactly equal, both are much larger than the distance between the beam deflection module 12 and the receiving module 14, and can be considered approximately equal. Therefore, the distance between the object 2 and the detection device 10 can be calculated based on the product of half the flight time t of the sensing beam reflected back from the object 2 and the speed of light c.

[0085] The receiving module 14 may include a photoelectric sensor 140 and a receiving optics 144. The receiving optics 144 is disposed on the light-incident side of the photoelectric sensor 140 and configured to transmit light signals from the detection range to the photoelectric sensor 140 for sensing. For example, in some embodiments, the receiving optics 144 includes a receiving lens (not shown). Optionally, the receiving lens may include one or more lenses. The photoelectric sensor 140 is configured to sense the light signals transmitted from the detection range via the receiving optics 144 and output a corresponding photosensitizing signal.

[0086] Optionally, in some embodiments, the receiving module 14 may further include peripheral circuitry (not shown) consisting of one or more devices such as signal amplifiers and analog-to-digital converters (ADCs), which may be partially or wholly integrated into the photoelectric sensor 140.

[0087] Optionally, in some embodiments, the photoelectric sensor 140 may include a single photosensitive pixel 142 or a plurality of photosensitive pixels 142 forming a photosensitive pixel array. The detection range of the detection device 10 may include a plurality of detection regions located at different positions. Optionally, the photosensitive pixels 142 of the photoelectric sensor 140 have corresponding detection regions within the detection range, and the light signal returned from the detection region is propagated through the receiving optics 144 to the corresponding photosensitive pixel 142 for sensing. That is, the detection region corresponding to the photosensitive pixel 142 can be regarded as the spatial range covered by the field of view formed by the receiving optics 144 of the photosensitive pixel 142. It should be understood that the light signal returned from the detection region includes the sensing beam that is projected onto the detection region and reflected back by the object 2 located within the detection region, as well as photons of ambient light from the detection region.

[0088] 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 photosensitized signal output. The photoelectric conversion device may be, for example, a single-photon avalanche diode (SPAD), an avalanche photodiode (APD), a silicon photomultiplier (SiPM) consisting of multiple SPADs connected in parallel, and / or other suitable photoelectric conversion elements.

[0089] like Figure 2 As shown, in some embodiments, the beam deflection module 12 includes a light source module 122, a polarization beam splitter 1224, an acousto-optic deflection module 124, and a secondary deflection module 126 arranged sequentially along the beam propagation direction. The light source module 122 is configured to emit a beam. The polarization beam splitter 1224 is disposed in the optical path before the beam enters the acousto-optic deflection module 124, and is configured to decompose the 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, which is different from the first polarization direction; for example, the first polarization direction and the second polarization direction are orthogonal to each other. The acousto-optic deflection module 124 is configured to deflect within a preset first deflection angle range according to the applied sound wave frequency. The first and second polarized beams are deflected by multiple different preset polarization angles along a preset first direction. The secondary deflection module 126 is configured to deflect the beams deflected by the acousto-optic deflection module 124 within a preset second deflection angle range. The beam is further deflected by a preset angle along the first direction to form sensing beams with different emission directions for different deflection angles. It should be understood that the first direction here refers to the deflection direction of the beam, which is different from the emission direction of the beam. The deflection direction of the beam can be understood as the direction in which the trend of change is indicated when the emission direction of the beam is changed.

[0090] like Figure 4 and Figure 5As shown, the beam deflection module 12 further includes a light guide 1228 and a polarization direction adjustment component 1226. The light guide 1228 is configured to guide the propagation direction of a first polarized beam or a second polarized beam, or both, so that the first polarized beam and the second polarized beam are incident on the acousto-optic deflection module 124 along different optical paths. The polarization direction adjustment component 1226 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 124 with the same preset polarization direction.

[0091] Specifically, for example, the polarizing beam splitter 1224 can be a polarizing prism formed by combining two calcite right-angle prisms with their inclined surfaces facing each other, such as a Glan-Foucault prism. The first polarized beam propagates along the principal optical axis of the beam incident direction through the combination interface of the polarizing beam splitter 1224 to the acousto-optic deflection module 124. The second polarized beam is reflected by the combination interface of the polarizing beam splitter 1224 and deviates from the principal optical axis of the beam incident direction, and is then guided by the light guide 1228 to propagate along a side optical path deviating from the principal optical axis to the acousto-optic deflection module. It should be noted that the principal optical axis here refers to the direction in which the different optical devices in the beam deflection module 12 are aligned with each other along their respective optical axes. It can be understood as the propagation direction of the beam emitted by the light-emitting unit 1220 after collimation, which remains unchanged after passing through each optical device in sequence, such as the direction of the zero-order beam after the beam passes through the acousto-optic deflection module 124.

[0092] It should be understood that in some other embodiments, the first polarized beam and the second polarized beam obtained by the polarization beam splitter 1224 may not propagate along the principal optical axis where the beam incident direction is located, but are guided by the light guide 1228 and propagate along different optical paths to the acousto-optic deflection module 124 respectively.

[0093] Optionally, the polarization direction adjustment element 1226 includes a liquid crystal layer, and the polarization direction of the light beam can be changed by adjusting the orientation of the liquid crystal molecules within the liquid crystal layer. For example... Figure 4 As shown, the polarization direction adjustment element 1226 can be disposed on the main optical axis of the beam deflection module 12 and is configured to change the first polarization direction of the first polarized beam to a second polarization direction. Optionally, as... Figure 5 As shown, the polarization direction adjustment element 1226 can also be disposed on the side branch optical path and configured to change the second polarization direction of the second polarized beam to the first polarization direction.

[0094] like Figure 4As shown, the light guide 1228 is, for example, a plurality of reflective optical elements, which guide the second polarized beam into the acousto-optic deflection module 124 in a direction parallel to the first polarized beam through multiple reflections. Optionally, in some other embodiments, the light guide 1228 may also be an optical fiber.

[0095] Optionally, by reasonably setting the first optical path length of the first polarized beam along the main optical axis and the second optical path length of the second polarized beam along the side optical path, a preset time difference can be achieved between the arrival times of the decomposed first polarized beam and the second polarized beam at the acousto-optic deflection module 124. The time difference between the arrival times of the first polarized beam and the second polarized beam, obtained from the decomposition of the same beam emitted by the corresponding light-emitting unit 1220, at the acousto-optic deflection module 124 can be equal to the emission period of the periodic emission of the sensing beam pulses by the beam deflection module 12, i.e., the time interval between two successively emitted sensing beam pulses. Thus, two sensing beam pulses emitted by the beam deflection module 12 can be obtained by emitting a beam once from the corresponding light-emitting unit 1220.

[0096] It should be understood that by setting a polarization beam splitter 1224 and corresponding polarization direction adjustment component 1226 and light guide component 1228 in the optical path of the beam deflection module 12, not only can the 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 beam can also be fully utilized for detection, thereby improving the utilization efficiency of the light-emitting power of the beam deflection module 12.

[0097] Optionally, such as Figure 6 As shown, in some embodiments, the light source module 122 is configured to emit a strip beam. The strip beam can be understood as a beam whose shape along a predetermined direction has a dimension significantly larger than its dimensions in other directions. For ease of description, the direction with the largest dimension can be defined as the length direction of the strip beam. For example, the shape of the strip beam can be a long rectangle, meaning the light spot illuminating the projection surface is a long rectangle with a pair of long sides and a pair of short sides. The extension direction of the long sides is the length direction of the strip beam. It should be understood that the shape of the strip beam is not limited to a long rectangle; for example, it can also be a long strip with rounded ends. If the acousto-optic deflection module 124 deflects the beam along the first direction, the length direction of the strip 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 horizontal, and the second direction is vertical; or, the first direction is vertical, and the second direction is horizontal.

[0098] Please refer to this again. Figure 4 or Figure 5The light source module 122 may include one or more light-emitting units 1220, which are configured to emit light beams. The light-emitting unit 1220 may be a vertical-cavity surface-emitting laser (VCSEL), an edge-emitting laser (EEL), a light-emitting diode (LED), a laser diode (LD), a fiber laser, or other similar light-emitting structures. The edge-emitting laser may be a Fabry-Perot (FP) laser, a distributed feedback (DFB) laser, an electro-absorption modulated (EML) laser, etc., and this embodiment does not limit the specific type of laser used.

[0099] Optionally, the multiple light-emitting units 1220 on the light source module 122 can be arranged in a long strip array, and the emitted light beam can be collimated into a strip beam propagating parallel to the optical axis. Optionally, the light source module 122 can use optical devices such as superlenses or cylindrical lenses to collimate the light beam emitted by the light-emitting units 1220, so as to improve the collimation of the strip beam emitted by the light source module 122.

[0100] Optionally, such as Figure 4 As shown, in some embodiments, the light source module 122 may further include a beam-shrinking optics device 1223, which can be used to narrow the cross-sectional size of the light beam, that is, the size of the light beam in a cross-section perpendicular to the beam propagation direction. The beam-shrinking optics device 1223 can be disposed in the optical path before the light beam enters the acousto-optic deflection module 124, and is configured to first shrink the collimated strip beam emitted by the light source module 122 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 ensure that all light beams incident on the acousto-optic deflection module 124 can enter from the incident area, the light beam needs to be modulated to a size matching the incident area before being transmitted to the acousto-optic deflection module 124. It should be understood that in other embodiments, if the collimated size of the light beam emitted by the light source module 122 already meets the requirements of the incident acousto-optic deflection module 124, the beam-shrinking optics device 1223 may also be omitted.

[0101] like Figure 7As shown, in some embodiments, the acousto-optic deflection module 124 includes an acousto-optic interaction medium 1241 and a sound wave generator 1242. The acousto-optic interaction medium 1241 has a preset light-incident surface 1244, a light-exit surface 1246, and a sound wave incident surface 1248. The sound wave generator 1242 is disposed on the sound wave incident surface 1248 and configured to generate sound waves propagating in a preset direction within 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 at a preset incident angle. Under the action of the sound waves, the acousto-optic interaction medium 1241 deflects the propagation direction of the light beam, and the deflected light beam exits from the light-exit surface 1246.

[0102] The incident angle can be defined as the angle between the incident direction of the light beam and the normal direction of the incident surface 1244. Optionally, in some embodiments, the material of the acousto-optic interaction medium 1241 is tellurium dioxide (TeO2), the incident angle ranges from 2 to 10 degrees, and there is a preset off-axis angle θ 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. α (Not shown in the image).

[0103] Optionally, in some embodiments, the acoustic wave generator 1242 may be a piezoelectric transducer, which generates ultrasonic waves that propagate into the acousto-optic interaction medium 1241 to deflect the propagation direction of the light beam passing through the acousto-optic interaction medium 1241 at a preset incident angle.

[0104] It should be understood that the propagation of sound waves within the acousto-optic interaction medium 1241 causes a change in the refractive index of the medium. By appropriately configuring parameters, anomalous Bragg diffraction can be achieved in the acousto-optic interaction medium 1241 under the influence of sound waves. The propagation direction of the resulting diffracted beam is deflected relative to the propagation direction of the incident beam, and the deflection angle α is related to the frequency f of the sound wave by the following formula:

[0105]

[0106] Where, θ d Let θ be the exit angle of the diffracted beam, and θ represent the propagation direction of the diffracted beam. i Let be the incident angle of the incident beam, represent the propagation direction of the incident beam, λ be the wavelength of the incident beam and the diffracted beam, n represent the refractive index of the acousto-optic interaction medium 1241, and V be the off-axis angle θ. α The relevant function value is denoted as V = V(θ). aThe parameters configured above include the wavelength, polarization state, incident angle, and propagation direction of the incident beam, as well as the frequency and propagation direction of the sound wave. Therefore, by changing the frequency of the sound wave applied to the acousto-optic interaction medium 1241, the deflection angle of the beam passing through the medium can be controlled. When the frequency of the sound wave changes by Δf, the deflection angle of the beam changes accordingly, i.e., the scanning angle is...

[0107] It should be noted that the deflection angle α and scanning angle Δα mentioned above refer to the angle inside the acousto-optic interaction medium 1241. In actual applications, the angle outside the acousto-optic interaction medium 1241 is used. According to the law of refraction, the angle outside the acousto-optic interaction medium 1241 needs to be multiplied by the corresponding refractive index factor. Furthermore, since sound wave propagation takes time, when the sound wave frequency just begins to change from f1 to f2, the sound wave frequency in the acousto-optic interaction medium 1241, which is immediately adjacent to the sound wave generator 1242, switches from f1 to f2, and the beam deflection angle changes from α1 to α2. The sound wave frequency and beam deflection angle in the remaining parts of the acousto-optic interaction medium 1241 have not yet changed. If the sound wave propagates through the entire area traversed by the beam within the acousto-optic interaction medium 1241, i.e., 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 f1 to f2, and the beam deflection angle completely changes to α2. Therefore, when adjusting the sound wave frequency to change the beam deflection angle, the deflection time τ required for the beam to complete one deflection can be considered equal to the sound wave transit time. The calculation of the deflection time τ satisfies the following relationship:

[0108]

[0109] Where W is the width of the acousto-optic interaction medium 1241, and V is the off-axis angle θ. α The relevant function value is denoted as V = V(θ). a ).

[0110] In the acousto-optic interaction medium 1241, the wave vectors of the diffracted beam, the incident beam, and the sound wave need to satisfy the momentum matching condition in order to form a stable and coherent diffracted beam within the acousto-optic interaction medium 1241. The incident angle of the beam that produces anomalous Bragg diffraction changes with the frequency of the sound wave. However, in practical applications, the incident angle of the beam in the acousto-optic interaction medium 1241 remains constant. As the frequency of the sound wave changes, the momentum matching condition no longer holds. The further the beam deviates from the momentum matching condition, the greater the decrease in diffraction efficiency. The range of sound wave frequencies that can effectively complete anomalous Bragg diffraction is called the Bragg bandwidth. Optionally, in some embodiments, the wavelength of the sensing 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 approximately 30 MHz, the scanning angle is approximately 40 milliradians (mrad), or approximately 2.3 degrees, the deflection time τ required to complete one beam deflection is approximately 10 microseconds (μs), the change accuracy of the acoustic wave frequency is approximately 30 kHz, and the corresponding change accuracy of the scanning angle is approximately 0.04 mrad. Achieving acousto-optic deflection within the tellurium dioxide crystal using anomalous Bragg diffraction requires the incident beam to have a right-handed e-ray component. Optionally, if the incident beam is linearly polarized e-ray, the diffracted beam emitted after acousto-optic deflection is linearly polarized o-ray; if the incident beam is right-handed circularly polarized, the diffracted beam emitted after acousto-optic deflection is left-handed circularly polarized. The utilization rate of the outgoing diffracted beam is determined by the ellipticity of the intrinsic mode right-handed e-beam of the incident beam, which in turn is determined by the wavelength of the incident light, the incident angle, and the material properties of the acousto-optic interaction medium 1241.

[0111] The acousto-optic deflection module 124 can deflect the passing light beam with high precision, but the angle range of the deflected beam is too small. Therefore, a secondary deflection module 126 can be set on the light-emitting side of the acousto-optic deflection module 124 to further deflect the light beam after it has been deflected by the acousto-optic deflection module 124 along the first direction to meet the requirements of large-angle, high-precision scanning. It should be understood that the secondary deflection module 126 deflects the light beam over a relatively large angle range, which can at least meet the application requirements of large-angle scanning scenarios.

[0112] Optionally, such as Figure 6 As shown, in some embodiments, the secondary deflection module 126 may be a superlens 1260, configured to deflect the light beam deflected by the acousto-optic deflection module 124 within a preset second deflection angle range. The beam is further deflected by a preset angle along the first direction and shaped to form sensing beams with different exit directions corresponding to different deflection angles. It should be understood that the metalens in this application, also known as metasurface lenses or meta-lenses, are structural arrays formed by arranging a large number of subwavelength structural units on a two-dimensional plane. Through the design of the shape, size, and macroscopic arrangement of the structural units and the two-dimensional array, the optical characteristics such as amplitude, phase, wavelength, and polarization state of the passing beam are modulated. Since the metalens are planar optical devices and relatively thin, beams passing through the metalens do not suffer from problems such as spherical aberration. Multiple light modulation sections are formed on the metalens 1260, arranged sequentially along the beam deflection direction. Beams passing through the multiple light modulation sections are deflected by different preset deflection angles before exiting. The light modulation sections are elongated, with their length direction perpendicular to the first direction. For example... Figure 8 As shown, the superlens 1260 includes an incident light side 1260a and an exit light side 1260b arranged opposite to each other. Each light modulation section has a corresponding incident light area and an exit light area on the incident light side 1260a and the exit light side 1260b, respectively. After the light beam enters the superlens 1260 from the incident light area of ​​one light modulation section, it is modulated and exits from the corresponding exit light area of ​​the same light modulation section at a preset deflection angle. Thus, the light beam, after being initially deflected by the acousto-optic deflection module 124, illuminates the incident light area of ​​the corresponding light modulation section on the superlens 1260 according to its different deflection angle, and after being modulated, exits from the corresponding exit light area of ​​the light modulation section at a preset deflection angle.

[0113] The superlens 1260 further deflects the light beam and can also reshape it, for example, but not limited to, expanding the divergence angle of the light beam along the first direction, or expanding the divergence angle of the light beam along the second direction, or expanding the divergence angle of the light beam along both the first and second directions. Since the first direction is the deflection direction by which the acousto-optic deflection module 124 and the superlens 1260 change the light beam emission angle, the superlens 1260 expanding the divergence angle of the light beam along the first direction allows the areas illuminated by the various sensing beams formed at different deflection angles in the far field to overlap along the first direction, thereby filling the angular gaps between adjacent deflection angles by the superlens 1260. Also, since both the acousto-optic deflection module 124 and the superlens 1260 deflect the light beam along the first direction, the superlens 1260 expanding the divergence angle of the light beam along the second direction allows the emitted light beam to form a long, strip-shaped sensing beam with its length direction parallel to the second direction. Therefore, the beam deflection module 12 only needs to deflect the elongated sensing beam in one dimension along the first direction to complete the scanning of the two-dimensional region defined by the first and second directions.

[0114] To facilitate the description of the scanning method of the elongated sensing beam, the propagation direction of the undeflected zero-order beam after passing through the acousto-optic deflection module 124 and the superlens 1260 can be taken as the Y-axis, the horizontal direction as the X-axis, and the vertical direction as the Z-axis. An orthogonal rectangular coordinate system can be established, with the horizontal plane as the XOY plane and the vertical plane as the YOZ plane. For example... Figure 6 As shown, in some embodiments, the first direction is the horizontal direction, that is, the elongated sensing beam emitted by the beam deflection module 12 is deflected along the horizontal direction of the X-axis, and the second direction is the vertical direction, that is, the length direction of the elongated sensing beam emitted after being expanded by the superlens 1260 is parallel to the vertical direction of the Z-axis. The process of the elongated sensing beam being deflected along the X-axis under the action of the acousto-optic deflection module 124 and the superlens 1260 can realize two-dimensional scanning in both the horizontal and vertical directions. It should be understood that the above coordinate system can also be established on Figures 4-5 This is to facilitate the description of the propagation of the light beam in the optical path.

[0115] 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 elongated sensing beam emitted by the beam deflection module 12 is deflected along the vertical direction of the Z-axis, and the length direction of the elongated sensing beam is parallel to the horizontal direction of the Y-axis. During the process of the elongated sensing beam being deflected along the Z-axis under the action of the acousto-optic deflection module 124 and the superlens 1260, two-dimensional scanning in both the vertical and horizontal directions can be achieved.

[0116] Specifically, in some embodiments, if the superlens 1260 deflects the light beam along the first direction, the second deflection angle range... With a divergence angle of ±30°, totaling 60°, and the beam's spread angle along the second direction extended to 25°, the emitted elongated sensing beam, when deflected along the first direction, can achieve a two-dimensional scan of the detection range of 60° × 25°. Correspondingly, if the acousto-optic deflection module 124 deflects the beam along the first direction within a first deflection angle range... With a deflection angle of 2.3° and a deflection accuracy of 0.1°, the beam deflected by the acousto-optic deflection module 124 has 23 different deflection angles, which can be configured to illuminate the 23 optical modulation units correspondingly arranged on the superlens 1260. The deflected beam emitted after modulation by each optical modulation unit covers a field of view of 2.6°×25°. That is, the divergence angle of the beam extending along the first direction through the superlens 1260 is 2.6°, and the divergence angle extending along the second direction is 25°.

[0117] Optionally, in some embodiments, the secondary deflection module 126 can be a projection optical system configured to project the beam deflected by the acousto-optic deflection module 124 along a preset emission direction corresponding to the detection range to form the sensing beam. The length direction of the strip beam emitted by the light source module 122 is the second direction, the acousto-optic deflection module 124 deflects the strip beam along the first direction, and the projection optical system 126 projects the strip beam deflected by the acousto-optic deflection module 124 along a preset emission direction corresponding to the detection range to form a strip-shaped sensing beam. It should be understood that the preset emission direction of the projection sensing beam projected by the projection optical system 126 is deflected by a larger angle than the incident direction of the strip beam after being deflected by the acousto-optic deflection module 124 and incident on the projection optical system 126 along the first direction. Moreover, there is a corresponding positive correlation between the deflection angle of the preset emission direction and the incident angle of the strip beam after being deflected by the acousto-optic deflection module 124. For example, the larger the incident angle between the incident direction of the deflected strip beam and the optical axis of the projection optical system 126, the larger the emission angle between the emission direction of the strip beam projected by the projection optical system 126 and the optical axis of the projection optical system 126 will be.

[0118] like Figure 9 As shown, the projection optical system 126 is disposed on the light-emitting side of the acousto-optic deflection module 124 and is configured to project the light beam deflected by the acousto-optic deflection module 124 out in a preset emission direction that further deflects it along a first direction, forming the sensing light beam. The emission direction of the sensing light beam emitted after being deflected by the projection optical system 126 is related to the deflection angle of the light beam after passing through the acousto-optic deflection module 124. The focal plane of the projection optical system 126 is located between the projection optical system 126 and the acousto-optic deflection module 124. The light beam deflected by the acousto-optic deflection module 124 passes through the corresponding area on the focal plane of the projection optical system 126 before being projected out by the projection optical system 126.

[0119] According to the Huygens-Fresnel principle, the region through which the light beam passes on the focal plane of the projection optics system 126 during propagation can serve as a secondary light source. The emitted light wave is deflected by the projection optics system 126 to form the sensing beam. Therefore, the region through which the light beam deflected by the acousto-optic deflection module 124 passes on the focal plane of the projection optics system 126 during propagation can be defined as the secondary light source region 125 formed by the light beam at that deflection angle on the focal plane. By adjusting the frequency of the acoustic wave applied to the acousto-optic interaction medium 1241, the secondary light source region 125 formed by the light beam deflected by the acousto-optic deflection module 124 can be moved on the focal plane of the projection optics system 126. The light beam generated by the secondary light source region 125 is then projected by the projection optics system 126 to form the sensing beam. The projection direction of the sensing beam also deflects accordingly as the secondary light source region 125 moves on the focal plane, thereby achieving a sensing beam within a preset second deflection angle range. A one-dimensional, large-angle, continuous sensing beam scan is performed along the first direction. Because the beam is further deflected along the first direction during projection by the projection optics system 126, the second deflection angle range... It will be within the range of the first deflection angle. Larger.

[0120] The light beams deflected at different angles by the acousto-optic deflection module 124 will form multiple secondary light source regions 125 arranged sequentially on the focal plane. The secondary light source region 125 formed by the beam with the larger deflection angle is relatively closer to the edge of the focal plane, while the secondary light source region 125 formed by the beam with the smaller deflection angle is relatively closer to the center of the focal plane. That is, if an imaging surface is placed on the focal plane, the light beams deflected at different angles by the acousto-optic deflection module 124 will form far-field spots corresponding to the locations of the multiple secondary light source regions 125 on the focal plane. The far-field spot formed by the beam with the largest deflection angle is located at the outermost edge of the multiple far-field spot locations on the focal plane, while the far-field spot formed by the undeflected or smallest deflection angle is located at the middle position of the multiple far-field spot locations on the focal plane.

[0121] Optionally, in some embodiments, by reasonably setting the positional relationship between the acousto-optic deflection module 124 and the projection optical system 126, the two adjacent secondary light source regions 125 formed on the focal plane of the projection optical system 126 before and after the acousto-optic deflection module 124 performs the minimum achievable angle deflection of the light beam (i.e., the deflection accuracy of the light beam by the acousto-optic deflection module 124) are tangent to each other. That is, if an imaging surface is placed on the focal plane, the two far-field light spots formed at different positions on the focal plane before and after the acousto-optic deflection module 124 performs the minimum angle deflection of the light beam are tangent to each other. It should be understood that in other embodiments, the regions on the focal plane of the projection optical system 126 before and after the acousto-optic deflection module 124 performs the minimum angle deflection of the light beam can also be separated or partially overlapped.

[0122] To facilitate the explanation of the quantitative relationship between the deflection angle of the light beam by the acousto-optic deflection module 124 and the emission angle of the deflected light beam projected by the projection optical system 126, it is assumed that the focal length of the projection optical system 126 is f, the distance between the focal plane of the projection optical system 126 and the center of the acousto-optic deflection module 124 is l, and the deflection accuracy of the light beam by the acousto-optic deflection module 124 is δα. Then, the center-to-center distance d ≈ l·δα between the two adjacent secondary light source regions 125 formed on the focal plane before and after the minimum achievable angle δα deflection by the acousto-optic deflection module 124, and the deflection accuracy ψ of the sensing light beam formed after projection by the projection optical system 126, is ψ = d / f. If the aperture of the secondary light source region 125 formed on the focal plane of the projection optical system 126 after the light beam deflected by the acousto-optic deflection module 124 is a, then the divergence angle φ of the sensing light beam formed after projection by the projection optical system 126 is φ = a / f. It should be understood that, for the sake of illustration, Figure 9 Only the light rays passing through the optical center of the projection optics system 126 are shown in the image. The acousto-optic deflection module 124 and the projection optics system 126 work together to achieve a second deflection angle range for the light beam. The number of secondary light source regions 125 formed on the focal plane of the projection optical system 126 by light beams deflected at different angles by the acousto-optic deflection module 124 is related to the deflection accuracy δα of the light beam by the acousto-optic deflection module 124.

[0123] Optionally, in some embodiments, the projection optical system 126 includes a projection lens 1260, which is a convex lens, and the focal plane of the convex lens is the focal plane of the projection optical system 126. Since the secondary light source region 125 formed on the focal plane is equivalent to a light source disposed on the focal plane emitting light to the convex lens, according to the imaging principle of a convex lens, the sensing beam formed by beams with the same deflection angle after passing through the convex lens and projected along a preset direction is a parallel beam. It should be understood that the projection optical system 126 can be a single lens or a lens combination including multiple lenses. If the projection optical system 126 is a lens combination of multiple lenses, the focal plane is the equivalent focal plane of the lens combination.

[0124] It should be understood that, when balancing the functionality and application performance requirements of the acousto-optic deflection module 124, the distance l between the focal plane of the projection optical system 126 and the center of the acousto-optic deflection module 124 will be relatively long, which is detrimental to module miniaturization. For example... Figure 10 As shown, in some embodiments, the beam deflection module 12 may further include a reflector 127. The beam deflected by the acousto-optic deflection module 124 is first reflected by the reflector 127 and then passes through the focal plane of the projection optical system 126 before being projected out by the projection optical system 126. In this case, the optical axis of the acousto-optic deflection module 124 is defined as the first optical axis, and the optical axis of the projection optical system 126 is defined as the second optical axis. The first optical axis and the second optical axis are not on the same straight line, but can form a preset angle with each other. Thus, the distance l between the focal plane of the projection optical system 126 and the center of the acousto-optic deflection module 124 can be divided into a first part l1 along the first optical axis and a second part l2 along the second optical axis, so that the length of the distance l in a single direction is reduced. Moreover, the length of each part of the distance l in different directions can be adjusted by changing the position and tilt angle of the reflector 127, which is beneficial to the miniaturization design of the module. Optionally, the first optical axis of the acousto-optic deflection module 124 and the second optical axis of the projection optical system 126 are arranged perpendicular to each other.

[0125] Optionally, 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 by different preset deflection angles to form sensing beams with different emission directions. The length direction of the strip beam emitted by the light source module 122 is the second direction. The acousto-optic deflection module 124 deflects the strip beam along the first direction, and the LCPG module 126 further deflects the strip beam deflected by the acousto-optic deflection module 124 along the first direction within a larger second deflection angle range. The LCPG module 126 deflects the light beam at multiple different preset deflection angles to form a strip-shaped sensing beam. It should be understood that the multiple preset deflection angles of the LCPG module 126 form an arithmetic sequence according to preset angular intervals, where the angular intervals can be considered as the angular tolerance of the arithmetic sequence. The first deflection angle range of the light beam by the acousto-optic deflection module 124 is... The angle interval is greater than or equal to the stated angle interval. Therefore, the acousto-optic deflection module 124 can finely adjust the beam deflection angle left and right with high deflection accuracy based on each beam deflection angle of the LCPG module 126. This fine adjustment of the beam deflection angle can cover the angle interval between every two adjacent beam deflection angles of the LCPG module 126, thereby enabling a larger second deflection angle range. The internal acousto-optic deflection module 124 deflects the beam with high deflection accuracy for scanning.

[0126] like Figure 11As 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 with different polarization states to deflection angles corresponding to different diffraction orders. The LCPG module 126 controls the deflection angle of the light beam by the LCPG sheet 1261 by changing the diffraction state of the LCPG sheet 1261 and / or the polarization state of the light beam incident on the LCPG sheet 1261. Optionally, the LCPG module 126 can change the diffraction state of the light beam by applying a voltage to change the liquid crystal orientation in the LCPG sheet 1261. For example, when the incident beam is circularly polarized and the phase retardation of the LCPG plate 1261 is an odd multiple of π, the polarization state of the incident beam and the phase retardation of the LCPG plate 1261 can be set so that the diffracted beam formed after passing through the LCPG plate 1261 switches between the deflection angles corresponding to the zeroth, positive first, and negative first diffraction orders of the grating. The deflection angle corresponding to each diffraction order is determined by the grating period of the LCPG plate 1261. Where λ is the incident wavelength, Λ is the grating period, m = 1, 0, -1, θ in ,θ out These represent the incident angle and the exit angle of the light beam, respectively.

[0127] Optionally, the LCPG module 126 may further include a liquid crystal half-wave plate 1262 to control the polarization state of the beam incident on the LCPG plate 1261. By adjusting the liquid crystal half-wave plate 1262 to change the polarization state of the beam incident on the LCPG plate 1261, and by applying a voltage to the LCPG plate 1261 to change the diffraction state of the LCPG plate 1261, the beam passing through the LCPG plate 1261 can be deflected to the deflection angles corresponding to the zeroth, positive first, and negative first diffraction orders. Multiple liquid crystal half-wave plates 1262 and LCPG plates 1261 of the LCPG module 126 can be cascaded. By combining and cascading multiple LCPG plates 1261 with different grating periods and controlling the voltage applied to the liquid crystal half-wave plate 1262 and LCPG plate 1261, the range of beam deflection angles and the number of beam deflection angles can be increased.

[0128] Optionally, such as Figure 12As shown, in some embodiments, the plurality of liquid crystal half-wave plates 1262 and LCPG plates 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 sequentially along the emission direction of the light beam. Each LCPG unit 1260 includes a liquid crystal half-wave plate 1262 and an LCPG plate 1261. The deflection angle of the LCPG plate 1261 to the light beam increases progressively in the order of their arrangement along the emission direction of the light beam, with the value being the index of the LCPG unit 1260 minus one. Correspondingly, the deflection angle of the LCPG module 126 to the light beam is a multiple of the minimum deflection angle of the LCPG plate 1261 to the light beam, where the multiple is the power of the index of the LCPG unit 1260 minus one.

[0129] Specifically, the LCPG module 126 includes M LCPG units 1260, each LCPG unit 1260 including a liquid crystal half-wave plate 1262 and an LCPG sheet 1261. The M LCPG units 1260 are arranged sequentially along the beam emission direction, and the deflection angle of the beam increases progressively in ascending order of power of two. That is, the first LCPG unit 1260 closest to the incident light side has the smallest deflection angle of the beam, while the last LCPG unit 1260 closest to the emitting light side has the largest deflection angle. Assuming the deflection angle of the first LCPG unit 1260 is r, the deflection angles of the M LCPG units 1260 arranged sequentially along the beam emission direction are ±r, ±2r, ±4r, ..., ±2r, respectively. M-1 r. Correspondingly, the entire LCPG module 126, including M LCPG units 1260, can deflect the passing beam by angles of 0, ±r, ±2r, ±3r…, ±(2 M -1)·r, it can be seen that the beam deflection angle provided by the LCPG module 126 is a multiple of the minimum deflection angle r of a single LCPG unit 1260 on the beam. The multiple is a natural number, with the maximum value being 2 to the power of M minus 1, 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 multiple preset deflection angles of the LCPG module 126 on the beam are distributed in an arithmetic sequence. The angular interval can be regarded as the angular tolerance of the arithmetic sequence, and the deflection accuracy of the beam is r. Therefore, the second deflection angle range of the LCPG module 126 on the beam based on the cascaded binary LCPG units 1260 is... The relationship between Ω and the total number of different deflection angles that can be provided is expressed as:

[0130]

[0131] Ω=(2 M+1 -1)

[0132] Where r is the minimum deflection angle of the passing beam among the M LCPG units 1260, and M is the total number of LCPG units 1260 in the LCPG module 126.

[0133] It should be understood that, based on the diffraction characteristics of the LCPG sheet 1261, the polarization state of the incident light beam can be either left-handed or right-handed circularly polarized light, depending on the grating vector direction of the LCPG sheet 1261 and a predefined deflection direction. Circularly polarized light can be generated from linearly polarized or unpolarized light. If the light beam emitted by the light source module 122 is linearly polarized, it can be converted into circularly polarized light by passing through a quarter-wave plate. If the light emitted by the light source module 122 is unpolarized or partially polarized, it can first be converted into linearly polarized light by passing through a polarizer, and then converted into circularly polarized light by passing through a quarter-wave plate. Therefore, the light source module 122 may also include a polarization device to adjust the polarization state of the emitted light beam to the corresponding circularly polarized light.

[0134] Optionally, such as Figure 13 As shown, in some embodiments, the liquid crystal half-wave plate 1262 and multiple LCPG plates 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 plates 1261 arranged sequentially along the beam emission direction. The deflection angle of the LCPG plates 1261 relative to the beam increases progressively according to their sequential arrangement along the beam emission direction. The difference between the deflection angle of one LCPG plate 1261 and its adjacent preceding LCPG plate 1261 increases progressively in the order of their sequential arrangement along the light path emission direction, each increasing by a power of two. The value of this power is the index of the LCPG plate 1261 minus one. Correspondingly, the deflection angle of the LCPG module 126 relative to the beam is a multiple of the minimum deflection angle of the LCPG plate 1261 relative to the beam, where the multiple is the power of two (LCPG plate index) minus one.

[0135] Specifically, the binary cascaded LCPG module 126 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 beam emission direction. The M LCPG plates 1261 are arranged sequentially along the beam emission direction, and their deflection angles to the beam increase progressively according to their arrangement. That is, the first LCPG plate 1261 closest to the light-incident side has the smallest deflection angle to the beam, while the last LCPG plate 1261 closest to the light-exit side has the largest deflection angle. Assuming the deflection angle of the first LCPG plate 1261 to the beam is r, the deflection angles of the M LCPG plates 1261 arranged sequentially along the beam emission direction are: ±r, ±3r, ±7r,…, ±(2 M -1)r. The difference in beam deflection angle between one of the LCPG plates 1261 and the adjacent LCPG plate 1261, arranged sequentially along the beam emission direction, is: ±2 1 r,±2 2 r,±2 3 r,…,±2 M-1 r, that is, increasing progressively by powers of 2, where the value of the natural number is the index of the LCPG chip 1261 minus one. Correspondingly, the entire LCPG module 126, including M LCPG chips 1261, can deflect the beam at angles of 0, ±r, ±2r, ±3r…, ±(2πr / 2πr). M -1)·r, it can be seen that the beam deflection angle provided by the LCPG module 126 is a multiple of the minimum deflection angle r of a single LCPG sheet 1261 on the beam. The multiple is a natural number, with the maximum value being 2 to the power of M minus 1, where 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 interval between multiple preset deflection angles of the LCPG module 126 on the beam is an arithmetic sequence, and the deflection accuracy of the beam is r. The angular interval r can be regarded as the angular tolerance of the arithmetic sequence. Therefore, the second deflection angle range of the LCPG module 126 on the beam based on the cascaded quasi-binary LCPG sheets 1261 is... The relationship between Ω and the total number of different deflection angles that can be provided is expressed as:

[0136]

[0137] Ω=(2 M+1 -1)

[0138] Where r is the minimum deflection angle of the passing beam among the M LCPG plates 1261, and M is the total number of LCPG plates 1261 in the LCPG module 126.

[0139] Compared to the binary cascaded LCPG unit 1260, the liquid crystal half-wave plate 1262 and LCPG plate 1261, which are cascaded in a quasi-binary manner, can set the desired beam deflection angle by deflecting the beam in different directions by the angle difference, thereby reducing the number of liquid crystal half-wave plates 1262 required and having higher beam transmittance.

[0140] Optionally, such as Figure 14 As shown, in some embodiments, the liquid crystal half-wave plate 1262 and LCPG plate 1261 of the LCPG module 126 can be cascaded in a ternary manner. The LCPG module 126 includes a plurality of LCPG units 1260 arranged sequentially along the beam emission direction. Each LCPG unit 1260 includes a liquid crystal half-wave plate 1262 and an LCPG plate 1261. The deflection angle of the LCPG plate 1261 relative to the beam increases progressively in the order of their arrangement along the beam emission direction, each increasing by a power of three. The value of the power of three is the index of the LCPG unit 1260 minus one. Correspondingly, the deflection angle of the LCPG module 126 relative to the beam is a multiple of half the minimum deflection angle of the LCPG plate 1261 relative to the beam, where the multiple is the power of three minus one.

[0141] Specifically, the LCPG module 126 includes M LCPG units 1260, each LCPG unit 1260 including a liquid crystal half-wave plate 1262 and an LCPG sheet 1261. The M LCPG units 1260 are arranged sequentially along the beam emission direction, and the deflection angle of the beam increases progressively in ascending order of power three. That is, the first LCPG unit 1260 closest to the light-incident side has the smallest deflection angle of the beam, while the last LCPG unit 1260 closest to the light-exit side has the largest deflection angle. Assuming the deflection angle of the first LCPG unit 1260 is r, then the deflection angles of the M LCPG units 1260 arranged sequentially along the beam emission direction are ±r, ±3r, ±9r, ..., ±3r, respectively. M-1 r. Correspondingly, the entire LCPG module 126, including M LCPG units 1260, can deflect the passing beam by an angle of r. It can be seen that the beam deflection angle provided by the LCPG module 126 is a multiple of half the minimum deflection angle r of a single LCPG unit 1260 on the beam. The multiple is a natural number, with the maximum value being 3 to the power of M minus 1, 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 multiple preset deflection angles of the LCPG module 126 on the beam are distributed in an arithmetic sequence, and the deflection accuracy of the beam is r. The angular interval can be regarded as the angular tolerance of the arithmetic sequence. Therefore, the second deflection angle range of the LCPG module 126 based on the cascaded three-valued LCPG units 1260 on the beam is... The relationship between Ω and the total number of different deflection angles that can be provided is expressed as:

[0142]

[0143] Ω = 3 M

[0144] Where r is the minimum deflection angle of the passing beam among the M LCPG units 1260, and M is the total number of LCPG units 1260 in the LCPG module 126.

[0145] Compared to the binary cascaded LCPG unit 1260, the ternary cascaded LCPG unit 1260 requires fewer liquid crystal devices to achieve the same beam deflection accuracy and deflection range, thus the ternary cascaded LCPG unit 1260 has higher beam transmittance.

[0146] It should be understood that the LCPG sheet 1261 in the above embodiments is an active LCPG sheet 1261 with electrodes that can adjust its effect on the passing light beam by whether or not a voltage is applied. Optionally, in some other embodiments, the LCPG sheet 1261 may also be a passive LCPG sheet 1261 without electrodes. Since the passive LCPG sheet 1261 is always in a diffraction state without voltage, it will deflect the passing light beam to different directions symmetrically distributed relative to the incident direction by a preset deflection angle according to the polarization state of the passing light beam, corresponding to the positive first-order diffraction and negative first-order diffraction of the passing light beam by the LCPG sheet 1261, respectively. The polarization state of the light beam passing through the passive LCPG sheet 1261 can be adjusted by using a liquid crystal half-wave plate 1262 on the light-incident side of the passive LCPG sheet 1261.

[0147] Optionally, such as Figure 15As shown, in some embodiments, the LCPG module 126 includes M passive LCPG units 1260, each passive LCPG unit 1260 including a liquid crystal half-wave plate 1262 and a passive LCPG sheet 1261. The M passive LCPG units 1260 are arranged in a binary cascade, and the M passive LCPG units 1260 are arranged sequentially along the beam emission direction, with the deflection angle of the beam increasing progressively in a power of two according to the order of their arrangement. That is, the first passive LCPG unit 1260 closest to the light-incident side has the smallest deflection angle of the beam, while the last passive LCPG unit 1260 closest to the light-exit side has the largest deflection angle of the beam. Assuming that the deflection angle of the first passive LCPG unit 1260 is r, then the deflection angles of the M passive LCPG units 1260 arranged sequentially along the beam emission direction are ±r, ±2r, ±4r, ..., ±2r, respectively. M-1 r. Correspondingly, the entire LCPG module 126, including M passive LCPG units 1260, can deflect the beam at angles of ±r, ±3r, ±5r…, ±(2 M -1)·r, it can be seen that the beam deflection angle provided by the LCPG module 126 is an odd multiple of the minimum deflection angle r of a single LCPG on the beam, and the maximum value of the odd multiple is 2 to the power of M minus 1, 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 LCPG module 126 on the beam are distributed in an arithmetic sequence, and the deflection accuracy of the beam is 2r. The angular interval can be regarded as the angular tolerance of the arithmetic sequence. Therefore, the second deflection angle range of the beam based on the binary cascaded passive LCPG units 1260 is... The relationship between Ω and the total number of different deflection angles that can be provided is expressed as:

[0148]

[0149] Ω=2 M

[0150] Where r is the minimum deflection angle of the passing beam among the M passive LCPG units 1260, and M is the total number of passive LCPG units 1260 in the LCPG module 126.

[0151] Compared to the active LCPG unit 1260 mentioned above, the passive LCPG unit 1260 does not require voltage adjustment to change the liquid crystal state of the passive LCPG plate 1261 during use. It only needs to change the voltage applied to the liquid crystal half-wave plate 1262 to achieve the control of the corresponding beam deflection angle, which has the advantages of fast response speed and simple driver program.

[0152] To ensure the proper functioning of the liquid crystal molecules within the LCPG sheet 1261, the temperature of the LCPG module 126 needs to be controlled to maintain it within a specific temperature range. Optionally, in some embodiments, such as... Figure 16 As shown, the LCPG module 126 may further include a temperature control unit, which is configured to control the temperature of the LCPG unit 1260 within a preset temperature range. The normal operating temperature range of the liquid crystal material is 0–70°C. In a low-temperature environment, the temperature control unit heats up the LCPG unit 1260; in a high-temperature environment, the temperature control unit cools down the LCPG unit 1260.

[0153] When cascading multiple LCPG units 1260, the influence of the grating vector direction of the LCPG sheet 1261 on beam deflection can also be considered. LCPG sheets 1261 with different grating vector directions will deflect beams with the same polarization state in different directions. For example, an LCPG sheet 1261 with a first grating vector direction will deflect incident left-handed circularly polarized light by the deflection angle corresponding to the positive first diffraction order, while an LCPG sheet 1261 with a second grating vector direction opposite to the first grating vector direction will deflect incident left-handed circularly polarized light by the deflection angle corresponding to the negative first diffraction order. Therefore, by matching the grating vector directions of the LCPG plates 1261, a cascaded method for deflecting the beam in different directions can be obtained. If the grating vector directions of two adjacent LCPG plates 1261 are the same, when a circularly polarized beam passes through these two LCPG plates 1261, since the LCPG plates 1261 will change the polarization state of the passing beam, the deflection direction of the passing beam by the latter LCPG plate 1261 will be opposite to the deflection direction of the beam by the former LCPG plate 1261. The total deflection angle of the beam after passing through the two LCPG plates 1261 is the difference between the deflection angles of the two LCPG plates 1261. If the grating vector directions of the two LCPG plates 1261 are opposite, when the circularly polarized light passes through these two LCPG plates 1261, the deflection direction of the beam by the latter LCPG plate 1261 is the same as the deflection direction of the beam by the former LCPG plate 1261. The total deflection angle of the beam after passing through the two LCPG plates 1261 is the sum of the deflection angles of the two LCPG plates 1261. Therefore, 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, making the control of the deflection angle of the light beam more flexible when multiple LCPG sheets 1261 are cascaded. 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.

[0154] like Figures 4-5 As shown, in some embodiments, the beam deflection module 12 may further include a beam adjustment element 123. The beam adjustment element 123 may be disposed between the acousto-optic deflection module 124 and the projection optics system 126, and is configured to adjust the beam before it enters the projection optics system 126.

[0155] Optionally, the beam adjustment element 123 may include a converging optics 123 configured to converge the beam polarized by the acousto-optic deflection module 124.

[0156] For example, the converging optics 123 can be disposed between the acousto-optic deflection module 124 and the superlens 1260 to converge the light beam deflected by the acousto-optic deflection module 124. As mentioned above, the incident side 1260a of the superlens 1260 has incident areas corresponding to different light modulation sections. The light beam deflected by the acousto-optic deflection module 124 at a predetermined angle needs to be incident into the corresponding incident area to be further deflected at a pre-designed angle. If the divergence angle of the light beam emitted after deflection by the acousto-optic deflection module 124 is too large, a portion of it will exceed the corresponding incident area when it illuminates the incident side 1260a of the superlens 1260 and cannot be effectively utilized, resulting in a waste of optical power. Therefore, the converging optics 123 can converge the light beams at various deflection angles emitted after deflection by the acousto-optic deflection module 124 to the corresponding incident areas on the incident side 1260a of the superlens 1260, thereby improving the utilization rate of the light beam. Optionally, the converging optical device 123 can achieve the beam-converging function by using a lens or a lens combination of multiple lenses, or by using a superlens; this application does not impose specific limitations on this. It should be understood that in some embodiments, if the divergence angle of the beam emitted from the acousto-optic deflection module 124 is small, or if the distance between the acousto-optic deflection module 124 and the superlens 1260 is close, beams with different deflection angles can be uniformly irradiated within the corresponding incident area of ​​the incident side 1260a of the superlens 1260, then the converging optical device 123 can also be omitted.

[0157] For example, the converging optics 123 can be disposed between the acousto-optic deflection module 124 and the focal plane of the projection optics system 126, so as to reduce the divergence angle of the beam when it passes through the focal plane of the projection optics system 126 by converging the beam, thereby reducing the size of the projection optics system 126 that needs to be configured, for example, reducing the size of the projection lens 1260. Figure 16 As shown, the beam deflected by the acousto-optic deflection module 124 forms sequentially arranged secondary light source regions 125 on the focal plane of the projection optical system 126 for each deflection angle. The divergence angle of the beam affects the space occupied by all the secondary light source regions 125 on the focal plane, thus determining the size of the projection optical system 126. For beams with large divergence angles after acousto-optic deflection, the divergence angle needs to be appropriately reduced before the beam enters the projection optical system 126 to reduce the size of the required projection optical system 126. It should be understood that in some embodiments, if the divergence angle of the beam deflected by the acousto-optic deflection module 124 is small, the converging optics can be omitted.

[0158] Optionally, the beam adjustment component 123 may include an LCPG module, which is disposed between the acousto-optic deflection module 124 and the focal plane of the projection optics system 126. The LCPG module is configured to further deflect the beam deflected by the acousto-optic deflection module 124 by a preset deflection angle to expand the beam deflection angle range before entering the projection optics system 126, thereby shortening the distance l between the focal plane of the projection optics system 126 and the center of the acousto-optic deflection module 124 while achieving the same beam scanning performance. Since the angular interval between different preset deflection angles of the beam by the LCPG module is relatively large, by configuring the deflection angle interval of the beam by the LCPG module and the first deflection angle range of the beam by the acousto-optic deflection module 124, If the LCPG module is sufficient, the deflection angle range of the acousto-optic deflection module 124 for the light beam can be multiplied. It should be understood that the LCPG module includes at least one LCPG sheet, and the cascading method between different LCPG sheets can be binary, quasi-binary, or ternary, and this application does not limit this.

[0159] It should be understood that, in some embodiments, the beam adjustment element 123 may also include both a converging optics and an LCPG module.

[0160] Since both the acousto-optic deflection module 124 and the secondary deflection module 126 deflect the light beam along the first direction, only a one-dimensional scan of the detection range by the light beam can be achieved. To achieve a two-dimensional scan of the detection range by the sensing light beam, such as... Figure 17 As shown, in some embodiments, the beam deflection module 12 further includes a beam expansion module 129. The beam expansion module 129 is disposed on the light-emitting side of the secondary deflection module 126, that is, on the side of the secondary deflection module 126 facing away from the acousto-optic deflection module 124, or in other words, the secondary deflection module 126 is located between the acousto-optic deflection module 124 and the beam expansion module 129. The beam expansion module 129 is configured to expand the beam along a second direction at a divergence angle to form an elongated sensing beam. The direction in which the sensing beam has its maximum size is defined as its length direction. The length direction of the elongated sensing beam is parallel to the second direction, and the second direction is perpendicular to the first direction.

[0161] Optionally, the beam expansion module 129 may include a diffuser sheet on which microstructures capable of modulating the beam are formed. The diffuser sheet is configured to expand the beam along the divergence angle of the second direction to form an elongated sensing beam. The direction in which the sensing beam has the largest size is defined as its length direction. The length direction of the elongated sensing beam is parallel to the second direction, and the second direction is perpendicular to the first direction.

[0162] Optionally, the diffuser is a refractive diffuser, and the microstructure achieves the function of expanding the divergence angle of the sensing beam along a preset direction by refracting the passing beam. Optionally, the diffuser can also be a diffractive diffuser, and the microstructure achieves the function of expanding the divergence angle of the sensing beam along a preset direction by diffracting the passing beam.

[0163] Optionally, the beam expansion module 129 may include a cylindrical beam expander lens 1290. Please refer to [further details omitted]. Figures 18-21 The cylindrical beam expander 1290 includes an optical surface curved along the beam expansion direction to bend the beam passing through the cylindrical beam expander 1290 along the beam expansion direction. In some embodiments, the beam expansion direction is a vertical direction, i.e., the Z-axis direction in the coordinate system described above. It should be understood that the curvature of the optical surface along the beam expansion direction can be described by the changes in curvature and / or slope of points arranged sequentially along the beam expansion direction on the optical surface in a predetermined direction.

[0164] like Figure 18 and Figure 19 As shown, in some embodiments, the cylindrical beam expander 1290 can be a plano-concave cylindrical lens. Using an orthogonal rectangular coordinate system established with the beam scanning direction as the X-axis, the beam expansion direction as the Z-axis, and the zero-order sensing beam emission direction as the Y-axis as a reference, the shape of the plano-concave cylindrical lens can be described accordingly. The plano-concave cylindrical lens includes an incident surface 1292 and an exit surface 1294 sequentially arranged along the Y-axis where the zero-order sensing beam emission direction is located. At least one of the incident surface 1292 and the exit surface 1294 is an optical surface curved along the beam expansion direction. Optionally, the incident surface 1292 is an inwardly concave curved surface recessed towards the Y-axis where the zero-order sensing beam emission direction is located, which can serve as the optical surface through which the cylindrical beam expander 1290 bends the beam. Optionally, in some embodiments, the incident surface 1292 has a varying curvature along the Z-axis where the beam expansion direction is located. That is, the curvature of each point on the incident surface 1292 changes with the coordinate of that point on the Z-axis along the beam propagation direction, such as... Figure 19 As shown, the incident light surface 1292 has a corresponding curved section 1295 on the cross-section formed by the YOZ plane of the coordinate system where the point is located. The curvature at this point refers to the curvature along the tangent direction of the curved section 1295 at that point. It should be understood that the cross-section forming the curved section 1295 can also be a plane perpendicular to the beam scanning direction.

[0165] Optionally, in some embodiments, the light-incident surface 1292 remains straight along the horizontal direction, and the intersection line between the light-incident surface 1292 and the plane parallel to the horizontal X-axis is a straight line, that is, the line connecting two points aligned along the horizontal X-axis on the light-incident surface 1292 is a straight line. However, this application is not limited thereto; in other embodiments, the intersection line between the light-incident surface 1292 and the plane parallel to the horizontal X-axis may also be a curve.

[0166] Optionally, the light-emitting surface 1294 can be a plane perpendicular to the Y-axis where the zero-order sensing beam is emitted. However, this application is not limited thereto. In some other embodiments, the light-emitting surface 1294 can also be a non-planar surface, or the light-emitting surface 1294 can also be a plane that is not perpendicular to the Y-axis where the zero-order sensing beam is emitted.

[0167] like Figure 20 and Figure 21 As shown, in some embodiments, the cylindrical beam expander 1290 can be a plano-convex cylindrical lens. Using an orthogonal rectangular coordinate system established with the beam scanning direction as the X-axis, the beam expansion direction as the Z-axis, and the zero-order sensing beam emission direction as the Y-axis as a reference, the shape of the plano-convex cylindrical lens can be described accordingly. The plano-convex cylindrical lens includes an incident surface 1292 and an exit surface 1294 sequentially arranged along the Y-axis where the zero-order sensing beam emission direction is located. At least one of the incident surface 1292 and the exit surface 1294 is an optical surface curved along the beam expansion direction. Optionally, the incident surface 1292 is an outwardly convex surface convex away from the Y-axis where the zero-order sensing beam emission direction is located, which can serve as the optical surface through which the cylindrical beam expander 1290 bends the beam. Optionally, in some embodiments, the incident surface 1292 has a varying curvature along the Z-axis where the beam expansion direction is located. That is, the curvature of each point on the incident surface 1292 changes with the coordinate of that point on the Z-axis along the beam propagation direction, such as... Figure 20 As shown, the incident light surface 1292 has a corresponding curved section 1295 on the cross-section formed by the YOZ plane of the coordinate system where the point is located. The curvature at this point refers to the curvature along the tangent direction of the curved section 1295 at that point. It should be understood that the cross-section forming the curved section 1295 can also refer to a plane perpendicular to the beam scanning direction.

[0168] Optionally, in some embodiments, the light-incident surface 1292 remains straight along the horizontal direction, and the intersection line between the light-incident surface 1292 and the plane parallel to the horizontal direction (i.e., the X-axis direction) is a straight line. That is, the line connecting two points aligned along the horizontal direction (i.e., the X-axis direction) on the light-incident surface 1292 is a straight line. However, this application is not limited to this; in other embodiments, the intersection line between the light-incident surface 1292 and the plane parallel to the horizontal direction (i.e., the X-axis direction) may also be a curve.

[0169] Optionally, the light-emitting surface 1294 can be a plane perpendicular to the emission direction of the zero-order sensing beam (i.e., the Y-axis direction). However, this application is not limited thereto. In some other embodiments, the light-emitting surface 1294 may also be non-planar, or the light-emitting surface 1294 may not be perpendicular to the emission direction of the zero-order sensing beam (i.e., the Y-axis direction).

[0170] like Figure 19 and Figure 21 As shown, optionally, the optical axis of the cylindrical beam expander 1290 is set along the direction of the zero-order sensing beam (i.e., the Z-axis direction), and the zero-order sensing beam is located at the middle position of the angle range of the beam deflected by the acousto-optic deflection module 124. Since the acousto-optic deflection module 124 only deflects the beam along the first direction, the beam deflected by the acousto-optic deflection module 124 is located at the middle position of the detection range when viewed from an angle perpendicular to the first direction. The divergence angle of the beam along the beam expansion direction after being expanded by the cylindrical beam expander 1290 is symmetrically distributed about the optical axis of the cylindrical beam expander 1290. If the divergence angle of the beam along the beam expansion direction after being expanded by the cylindrical beam expander 1290 is 2θ, then the maximum deviation angle of the beam from the optical axis after being bent by the cylindrical beam expander 1290 is θ, and θ satisfies the following relationship:

[0171]

[0172] Where D is the diameter of the beam, and f is the focal length of the cylindrical beam expander 1290. For example, if the divergence angle of the sensing beam expanded by the beam expander 1290 is preset to reach 70 degrees, then θ = 0.61 rad, and the focal length...

[0173] It should be understood that the curvature variation of the incident surface 1292 of the cylindrical beam expander 1290 along the beam expansion direction can be set according to any one or more combinations of factors such as the beam diameter when the sensing beam is incident, the divergence angle of the sensing beam after being expanded by the cylindrical beam expander 1290, the refractive index of the material of the cylindrical beam expander 1290, and the thickness of the cylindrical beam expander 1290 along the Y-axis where the zero-order sensing beam emission direction is located.

[0174] Optionally, in some other embodiments, the curvature of the incident surface 1292 of the cylindrical beam expander 1290 along the Z-axis of the beam expansion direction can also be described by the slope variation of various points distributed along the beam expansion direction on the incident surface 1292. For example... Figure 19 As shown, the YOZ plane is defined by the Z-axis where the beam expansion direction is located and the Y-axis where the emission direction of the zero-order beam is located. Within the cross-section formed by the cylindrical beam expander 1290 through the YOZ plane, the incident surface 1292 of the cylindrical beam expander 1290 corresponds to a first curved section 1295. The slope of each point on this first curved section 1295 varies according to the Y-axis coordinate of that point. That is, within the cross-section of the cylindrical beam expander 1290 perpendicular to the beam scanning direction, the slope of each point on the first curved section 1295 formed by the incident surface 1292 varies with the position of that point on the Y-axis where the beam expansion direction is located. Taking the cylindrical beam expander 1290 as a plano-concave cylindrical lens as an example, the incident surface 1292 is a concave curved surface that is recessed towards the emission direction of the zero-order beam. The slope of each point on the first curved section 1295 formed by the incident surface 1292, distributed from top to bottom along the Z-axis where the beam expansion direction is located, gradually decreases. That is, the slope of each point on the incident surface 1292 varies with the position of that point on the Z-axis along the beam propagation direction. For example... Figure 21 As shown, taking the cylindrical beam expander lens 1290 as a plano-convex cylindrical lens as an example, the light-incident surface 1292 is an outwardly convex surface protruding away from the direction of the zero-order sensing beam. The slope of each point distributed along the Z-axis of the first curved section 1295 formed by the light-incident surface 1292 from top to bottom gradually increases along the beam expansion direction. That is, the slope of each point on the light-incident surface 1292 varies with the position of that point on the Y-axis of the beam expansion direction.

[0175] like Figure 22 As shown, in some embodiments, the beam expansion module 129 includes a collimating lens 1291, a cylindrical beam expander lens 1290, and an emitting lens 1293, which are arranged sequentially along the emission direction of the zero-order beam. Optionally, the optical axes of the collimating lens 1291, the cylindrical beam expander lens 1290, and the emitting lens 1293 are arranged along the same straight line to form the optical axis of the beam expansion module 129. The optical axis of the beam expansion module 129 is aligned with the emission direction of the zero-order beam of the acousto-optic deflection module 124. The zero-order beam refers to the beam located at the middle angle within the beam deflection angle range of the acousto-optic deflection module 124. It should be understood that the emission direction of the zero-order beam is also the straight line direction along which the optical axis of the acousto-optic deflection module 124 is located.

[0176] The collimating lens 1291 is configured to collimate the light beam emitted after being deflected by the acousto-optic deflection module 124 along a direction parallel to the optical axis of the cylindrical beam expander lens 1290. Optionally, in some embodiments, the collimating lens 1291 is a thin convex lens.

[0177] The cylindrical beam expander 1290 is configured to expand the divergence angle of the beam collimated by the collimating lens 1291 along a predetermined second direction. The cylindrical beam expander 1290 includes an optical surface curved along the beam expansion direction to bend the beam passing through the cylindrical beam expander 1290 along the beam expansion direction. Optionally, in some embodiments, the cylindrical beam expander 1290 can be a cylindrical lens, such as those described above. Figure 18 and Figure 19 Plano-concave cylindrical lenses or Figure 20 and Figure 21 The plano-convex cylindrical lens, as described herein, will not be elaborated further. The plano-concave and plano-convex cylindrical lenses remain flat along the X-axis containing the beam scanning direction. However, since the collimating lens 1291 has already collimated the beam along the optical axis, the incident direction of the collimated beam is perpendicular to the beam scanning direction maintained flat by the plano-concave and plano-convex cylindrical lenses. Therefore, the collimated beam will not be distorted after being expanded by the plano-concave or plano-convex cylindrical lens.

[0178] The emitting lens 1293 is configured to emit the beam whose divergence angle has been expanded by the cylindrical beam expander 1290 along the direction originally emitted from the acousto-optic deflection module 124, as the sensing beam of the detection device 10. Since the beam collimated by the collimating lens 1291 is incident on the cylindrical beam expander 1290 along the Y-axis, which is parallel to the optical axis or the direction of emission of the zero-order beam, and the cylindrical beam expander 1290 remains flat along the X-axis, which is the direction of beam scanning, the beam incident parallel to the optical axis is expanded by the cylindrical beam expander 1290 only along the beam expansion direction, and its projection on the XOY plane defined by the beam scanning direction and the direction of emission of the zero-order beam remains parallel. In this case, although the expanded beam will not be distorted, it cannot reflect the emission angle after being deflected by the acousto-optic deflection module 124. Therefore, the emitting lens 1293 can deflect the expanded beam back to the original direction emitted from the acousto-optic deflection module 124. Optionally, in some embodiments, the emitting lens 1293 is a thin concave lens.

[0179] It should be understood that the lenses mentioned in the above description of the embodiments of this application, such as projection lens 1260, collimating lens 1291, cylindrical beam expander lens 1290 and emitting lens 1293, can be a single lens or a lens group including multiple lenses. This application does not make specific limitations in this regard.

[0180] Therefore, it can be seen that by first collimating the beams deflected in different directions by the acousto-optic deflection module 124 and then expanding the beams using the cylindrical beam expander lens 1290, the beam distortion caused by passing through the plano-concave cylindrical lens or the plano-convex cylindrical lens from different angles can be reduced.

[0181] To facilitate the description of the scanning method of the elongated sensing beam, as follows: Figure 17 As shown, taking the propagation direction of the undeflected zero-order beam after passing through the acousto-optic deflection module 124 and the secondary deflection module 126 as the Y-axis, the horizontal direction as the X-axis, and the vertical direction as the Z-axis, an orthogonal rectangular coordinate system is established. The horizontal plane is then the XOY plane, and the vertical plane is the YOZ plane. Figure 17 In this embodiment, the first direction is the horizontal direction, meaning the elongated sensing beam emitted by the beam deflection module 12 is deflected along the horizontal direction of the X-axis. The second direction is the vertical direction, meaning the length direction of the elongated sensing beam formed by the beam expansion module 129 expanding the divergence angle is parallel to the vertical direction of the Z-axis. The process of the elongated sensing beam deflecting along the X-axis under the action of the acousto-optic deflection module 124 and the secondary deflection module 126 can realize two-dimensional scanning in both the horizontal and vertical directions. It should be understood that the above coordinate system can also be established on... Figures 4-5 This is to facilitate the description of the propagation of the light beam in the optical path.

[0182] 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 elongated sensing beam emitted by the beam deflection module 12 is deflected along the vertical direction of the Z-axis, and the length direction of the elongated sensing beam formed by the beam expansion module 129 expanding the divergence angle is parallel to the horizontal direction of the Y-axis. During the process of the elongated sensing beam being deflected along the Z-axis under the action of the acousto-optic deflection module 124 and the projection optics system 126, two-dimensional scanning in the vertical and horizontal directions can be achieved.

[0183] Optionally, in embodiments where the secondary deflection module 126 is a superlens or a projection optical system, the detection device 10 further includes a control circuit 18 (see...). Figure 2 The control circuit 18 is configured to control the beam deflection module 12 to emit a sensing beam to scan the detection range, and to control the receiving module 14 to sense the beam returning from the detection range in conjunction with the scanning of the sensing beam. Optionally, in some embodiments, the control circuit 18 may include a light source control unit, an acousto-optic deflection control unit, and a sensing control unit.

[0184] The light source control unit 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 mathematically statistically meaningful, the light source control unit controls the corresponding light-emitting unit 1220 to emit multiple sensing beam pulses at a preset frequency within a detection frame, such as tens, hundreds, thousands, tens of thousands, or even millions. The time interval between the emission times of two adjacent sensing beam pulses can be defined as one emission period of the sensing beam pulse.

[0185] The sensing control unit is configured to control the photosensitive pixel 142 to perform sensing during the sensing period corresponding to the emission period of the corresponding light-emitting unit 1220, in order to count in response to the light signal returned from the detection range. Since the light-emitting unit 1220 periodically emits sensing beam pulses at a preset frequency, the corresponding photosensitive pixel 142, under the control of the sensing control unit, periodically performs sensing at the same preset frequency as the emission period. Optionally, the sensing control unit may also control some of the photosensitive pixels 142 to cooperate with the optical device 144 to sense light signals returned from preset different directions.

[0186] The acousto-optic deflection control unit is configured to control the acousto-optic deflection module 124 within a corresponding first deflection angle range. The beam passing through the optical system is deflected by a preset deflection angle. As mentioned earlier, the acousto-optic deflection control unit can control the deflection angle of the passing beam by the acousto-optic deflection module 124 by adjusting the frequency of the sound waves applied to the acousto-optic interaction medium 1241. The deflection time τ required for the acousto-optic deflection module 124 to change the beam deflection angle once is approximately 10 microseconds. It should be understood that for each beam deflection angle, the beam deflection module 12 needs to emit multiple sensing beam pulses to detect the distance information in the direction illuminated by that beam deflection angle, and the corresponding photosensitive pixels 142 on the receiving module 14 work synchronously to sense the light signal returning from that direction. The number of sensing beam pulses emitted by the beam deflection module 12 along different beam deflection angles can be different. For example, the number of sensing beam pulses emitted along the direction can be set according to the maximum distance detection value that the detection device 10 needs to satisfy in the direction of illumination at each beam deflection angle. Similarly, the photosensitive pixel 142 configured to sense the light signal in the direction on the receiving module 14 can be set to the number of sensing time periods within a detection frame according to the maximum distance detection value that needs to be satisfied in the direction.

[0187] In use, the acoustic-optical deflection control unit controls the acoustic-optical deflection module 124 to operate within the corresponding first deflection angle range. The light beam is deflected with a preset acousto-optic deflection precision δ. For each preset deflection angle of the light beam, the light source control unit controls the light-emitting unit 1220 to periodically emit sensing beam pulses in the direction corresponding to the deflection angle of the light beam according to a preset frequency and number of times. The sensing control unit controls the corresponding photosensitive pixel 142 to synchronously sense the light signal returned from the direction corresponding to the deflection angle of the light beam, so as to perform three-dimensional detection in the direction corresponding to the deflection angle of the light beam.

[0188] Optionally, in embodiments where the secondary deflection module 126 is an LCPG module, the detection device 10 further includes a control circuit 18. The control circuit 18 is configured to control the beam deflection module 12 to emit a sensing beam to scan the detection range, and to control the receiving module 14 to sense the beam returning from the detection range in conjunction with the scanning of the sensing beam. Optionally, in some embodiments, the control circuit 18 may include a light source control unit, an acousto-optic deflection control unit, an LCPG control unit, and a sensing control unit.

[0189] The light source control unit 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 mathematically statistically meaningful, the light source control unit controls the corresponding light-emitting unit 1220 to emit multiple sensing beam pulses at a preset frequency within a detection frame, such as tens, hundreds, thousands, tens of thousands, or even millions. The time interval between the emission times of two adjacent sensing beam pulses can be defined as one emission period of the sensing beam pulse.

[0190] The sensing control unit is configured to control the photosensitive pixel 142 to perform sensing during the sensing period corresponding to the emission period of the corresponding light-emitting unit 1220, in order to count in response to the light signal returned from the detection range. Since the light-emitting unit 1220 periodically emits sensing beam pulses at a preset frequency, the corresponding photosensitive pixel 142, under the control of the sensing control unit, periodically performs sensing at the same preset frequency as the emission period. Optionally, the sensing control unit may also control some of the photosensitive pixels 142 to cooperate with the optical device 144 to sense light signals returned from preset different directions.

[0191] The LCPG control unit is configured to control the LCPG module 126 within a second deflection angle range. The LCPG control unit deflects the passing light beam by a preset deflection angle, with the deflection angles arranged in an arithmetic sequence according to preset angular intervals r. Optionally, the LCPG control unit 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 correspondence between the deflection angle of the passing light beam and the applied voltage signal differs for LCPG units 1260 with different cascade configurations. The LCPG control unit can select the voltage control signal to be applied based on the cascade configuration of the LCPG units 1260 used in the LCPG module 126 and the current desired deflection angle of the sensed light beam.

[0192] The acousto-optic deflection control unit is configured to control the acousto-optic deflection module 124 within a corresponding first deflection angle range. The beam passing through the optical system is deflected by a preset deflection angle. As mentioned earlier, the acousto-optic deflection control unit can control the deflection angle of the passing beam by the acousto-optic deflection module 124 by adjusting the frequency of the sound waves applied to the acousto-optic interaction medium 1241. The deflection time τ required for the acousto-optic deflection module 124 to change the beam deflection angle once is approximately 10 microseconds. It should be understood that for each beam deflection angle, the beam deflection module 12 needs to emit multiple sensing beam pulses to detect the distance information in the direction illuminated by that beam deflection angle, and the corresponding photosensitive pixels 142 on the receiving module 14 work synchronously to sense the light signal returning from that direction. The number of sensing beam pulses emitted by the beam deflection module 12 along different beam deflection angles can be different. For example, the number of sensing beam pulses emitted along the direction can be set according to the maximum distance detection value that the detection device 10 needs to satisfy in the direction of illumination at each beam deflection angle. Similarly, the photosensitive pixel 142 configured to sense the light signal in the direction on the receiving module 14 can be set to the number of sensing time periods within a detection frame according to the maximum distance detection value that needs to be satisfied in the direction.

[0193] In use, the LCPG control unit can control the LCPG module 126 to be configured within a preset second deflection angle range. The coarse deflection angle of the beam is adjusted, and the coarse deflection angles are arranged in an arithmetic sequence according to a preset angle interval r, where the angle interval r is the coarse deflection accuracy of the LCPG module 126. The acousto-optic deflection control unit controls the acousto-optic deflection module 124 within a first deflection angle range centered on the already deflected coarse deflection angle. The beam deflection angle is finely adjusted using a preset acousto-optic deflection precision δ. For each preset deflection angle of the beam after deflection by the acousto-optic deflection module 124 and the LCPG module 126, the light source control unit 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. The sensing control unit controls the corresponding photosensitive pixel 142 to synchronously sense the light signal returned from the direction corresponding to the beam deflection angle, so as to perform three-dimensional detection in the direction corresponding to the beam deflection angle.

[0194] Compared to deflecting the sensing beam through mechanical rotation and hybrid solid-state methods, this application achieves quasi-continuous deflection of the sensing beam within a preset deflection angle range using a pure solid-state acousto-optic deflection module 122 and a secondary deflection module 126. This eliminates the need for component rotation and vibration, resulting in better reliability and a more compact size.

[0195] Please refer to the following: Figure 2 , Figure 23 and Figure 24In some embodiments, the beam deflection module 12 periodically emits laser pulses as a sensing beam at a preset frequency. The laser pulses are projected onto the detection range by emitting optics such as the acousto-optic deflection module 124, the secondary deflection module 126, and the beam expansion module 129. That is, the sensing beam can be a periodic pulse beam with a preset frequency. The beam deflection module 12 can emit multiple laser pulses within one detection frame, and the time interval between the emission times 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 illuminated by the laser pulse has a sensing period corresponding to the emission period. For example, the corresponding photosensitive pixel 142 performs sensing periodically at the same preset frequency as the emission period, and the sensing period has the same start and end times as the emission period. Simultaneously with the emission of each laser pulse, the photosensitive pixel 142 begins to sense photons returning from the detection range, and the timing unit 152 determines the reception time of the light signal sensed by the photosensitive pixel 142 based on the light sensing signal generated by the photons sensed by the corresponding photosensitive pixel 142. The statistics unit 154 performs counting statistics within corresponding time bins based on the light signal reception time determined by the timing unit 152 during multiple sensing periods in a detection frame, thereby generating a corresponding statistical histogram. The length of the sensing period is at least greater than the flight time required for a photon to travel to and from the corresponding detection area at the furthest detection distance, ensuring that photons reflected back from the furthest detection distance can be sensed and counted. Optionally, in some embodiments, the length of the sensing period can be set according to the required furthest detection distance of the detection area. For example, the sensing period length of the photosensitive pixel 142 is positively correlated with the furthest detection distance required for the corresponding detection area. For detection areas with larger furthest detection distances, the sensing period of the photosensitive pixel 142 performing the corresponding detection is longer; for detection areas with smaller furthest detection distances, the sensing period of the photosensitive pixel 142 performing the corresponding detection is shorter.

[0196] Optionally, in some embodiments, all or part of the functional units in the control circuit 18 and / or processing circuit 15 may be firmware embedded 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 the relevant components to achieve the corresponding functions. The processor 40 may be, for example, but not limited to, an application processor (AP), a central processing unit (CPU), a microcontroller (MCU), etc. The storage medium 30 may include, but is not limited to, flash memory, electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), hard disk, etc.

[0197] Optionally, in some embodiments, the processor 40 and / or storage medium 30 may be disposed within the detection device 10, for example, integrated on the same circuit board as the beam deflection module 12 or the receiving module 14. Optionally, in other embodiments, the processor 40 and / or storage medium 30 may also be disposed in other locations on the electronic device 1, such as on the main circuit board of the electronic device 1.

[0198] Optionally, in some embodiments, some or all of the functional units of the control circuit 18 and / or processing circuit 15 may also be implemented in hardware, for example, by any one or a combination of the following techniques: discrete logic circuits having logic gates for implementing logic functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc. It is understood that the hardware used to implement the functions of the control circuit 18 and / or processing circuit 15 may be located within the detection device 10. The hardware used to implement the functions of the control circuit 18 and / or processing circuit 15 may also be located in other locations on the electronic device 1, such as on the main circuit board of the electronic device 1.

[0199] like Figure 25 As shown, in some embodiments, the detection device 10 is, for example, a lidar, and the electronic device 1 is, for example, a car. The lidar can be installed in multiple different locations on the car to detect the distance information of objects within the car's surrounding area and thereby enable driving control.

[0200] Compared to lidar that uses mechanical rotation and hybrid solid-state methods to achieve sensing beam scanning, the lidar provided in this application uses a pure solid-state acousto-optic deflection module 124 and a secondary deflection module 126 to achieve sensing beam deflection scanning. Since it no longer relies on rotating or vibrating components, it has higher reliability and a more compact structure, is easier to pass strict automotive-grade requirements, and has less impact on the appearance of the car.

[0201] It should be noted that the technical solution to be protected by this application may satisfy only one of the above embodiments or simultaneously satisfy multiple of the above embodiments. In other words, embodiments composed of one or more of the above embodiments also fall within the protection scope of this application.

[0202] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with the said embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0203] It should be understood that various parts of the embodiments of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple functional units can be implemented using software or firmware stored in a storage medium and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0204] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A beam deflection module based on a polarization beam splitter, characterized in that, Configured to emit a sensing beam for three-dimensional information detection within a detection range, it includes a light source module, a polarization beam splitter, an acousto-optic deflection module, and a superlens arranged sequentially along the beam propagation direction. The light source module is configured to emit a light beam; The polarization beam splitter is disposed in the optical path before the light beam enters the acousto-optic deflection module, and is configured to decompose the passing light beam into a first polarized beam with a first polarization direction and a second polarized beam with a second polarization direction, wherein the first polarization direction is different from the second polarization direction. The beam deflection module further includes a light guide and a polarization direction adjustment component. The light guide is configured to guide the propagation direction of the first polarized beam or the second polarized beam, or to guide both the first polarized beam and the second polarized beam, so that the first polarized beam and the second polarized beam are incident on the acousto-optic deflection module along different optical paths. The polarization direction adjustment component is configured to change the first polarization direction of the first polarized beam or the second polarization direction of the second polarized beam, so that both enter the acousto-optic deflection module with the same preset polarization direction. The acousto-optic deflection module is configured to deflect the first polarized beam and the second polarized beam at multiple different preset deflection angles within a preset first deflection angle range and along a preset first direction, according to the applied sound wave frequency; wherein the beam emitted by the light source module is a bar-shaped collimated beam, the direction in which the bar-shaped collimated beam has its maximum size is defined as its length direction, the length direction of the bar-shaped collimated beam is parallel to a preset second direction, and the second direction is perpendicular to the first direction; and The superlens is configured to further deflect and shape the light beam deflected by the acousto-optic deflection module along the first direction by a preset angle, so as to form sensing light beams with different exit directions corresponding to different deflection angles.

2. The beam deflection module as described in claim 1, characterized in that, The first direction is horizontal, and the second direction is vertical; or The first direction is the vertical direction, and the second direction is the horizontal direction.

3. The beam deflection module as described in claim 1, characterized in that, The superlens extends the divergence angle of the passing beam along the second direction to form the elongated sensing beam, the second direction being perpendicular to the first direction.

4. The beam deflection module as described in claim 1, characterized in that, The superlens extends the divergence angle of the transmitted light beam along the first direction, so that the respective sensing light beams formed along different deflection angles partially overlap each other in their respective far-field irradiated regions along the first direction.

5. The beam deflection module as described in claim 1, characterized in that, The system further includes a projection optical system configured to project the beam deflected by the acousto-optic deflection module along a preset emission direction corresponding to the beam deflection angle within the detection range to form the sensing beam; wherein the beam deflected by the acousto-optic deflection module passes through a corresponding area on the focal plane of the projection optical system and is then projected by the projection optical system, and the corresponding area moves on the focal plane as the beam deflection angle changes.

6. The beam deflection module as described in claim 5, characterized in that, The focal plane is located between the acousto-optic deflection module and the projection optical system, and the corresponding area on the focal plane serves as a secondary light source area to emit the sensing beam.

7. The beam deflection module as described in claim 1, characterized in that, It further includes a liquid crystal polarization grating module, configured to further deflect the light beam deflected by the acousto-optic deflection module at multiple times by corresponding preset deflection angles to form the sensing light beam.

8. The beam deflection module as described in claim 7, characterized in that, The liquid crystal polarization grating module deflects the beam at multiple preset deflection angles in an arithmetic sequence according to a preset first angular interval, wherein the range of the first deflection angle is greater than or equal to the first angular interval.

9. The beam deflection module as described in claim 5, characterized in that, The system further includes a beam expansion module disposed on the light-emitting side of the projection optical system. The beam expansion module is configured to expand the sensing beam along the divergence angle of a second direction to form an elongated sensing beam. The second direction is perpendicular to the first direction.

10. The beam deflection module as described in claim 7, characterized in that, The device further includes a beam expansion module disposed on the light-emitting side of the liquid crystal polarization grating module. The beam expansion module is configured to expand the sensing beam along the divergence angle of the second direction to form the elongated sensing beam. The second direction is perpendicular to the first direction.

11. The beam deflection module as described in claim 9 or 10, characterized in that, The beam expansion module includes a refractive diffuser, on which a microstructure capable of modulating the beam is formed. The microstructure achieves the function of expanding the sensing beam divergence angle along a preset direction by refracting the beam.

12. The beam deflection module as described in claim 9 or 10, characterized in that, The beam expansion module includes a diffraction diffuser plate, on which a microstructure capable of modulating the beam is formed. The microstructure achieves the function of expanding the sensing beam divergence angle along a preset direction by diffracting the beam.

13. The beam deflection module as described in claim 9, characterized in that, The beam expansion module includes a cylindrical beam expander lens, which includes an optical surface that is bent along the second direction to expand the divergence angle of the sensed beam along the second direction.

14. The beam deflection module as described in claim 13, characterized in that, The beam expansion module further includes a collimating lens and an emitting lens. The collimating lens is disposed on the incident light side of the cylindrical beam expander and is configured to collimate the sensing beam projected by the projection optical system along the optical axis before it enters the cylindrical beam expander. The emitting lens is disposed on the exit light side of the cylindrical beam expander and is configured to re-emit the sensing beam, whose divergence angle has been expanded by the cylindrical beam expander, along the direction in which the sensing beam was originally projected from the projection optical system.

15. The beam deflection module as described in claim 1, characterized in that, The light source module further includes a beam-shrinking optics device, which is configured to reduce the light beam to a preset size before transmitting it to the acousto-optic deflection module.

16. The beam deflection module as described in claim 1, characterized in that, The first polarized beam and the second polarized beam, after being decomposed, arrive at the acousto-optic deflection module at a preset time difference.

17. The beam deflection module as described in claim 1, characterized in that, When the first polarized beam is incident on the polarization beam splitter, the principal optical axis containing the incident direction propagates through the polarization beam splitter to the acousto-optic deflection module. The polarization direction adjustment component is disposed on the principal optical axis and is configured to change the first polarization direction of the first polarized beam to the second polarization direction.

18. The beam deflection module as described in claim 1, characterized in that, After passing through the polarization beam splitter, the second polarized beam propagates along a side path of the main optical axis that deviates from the incident direction of the beam when it enters the polarization beam splitter, and then to the acousto-optic deflection module. The polarization direction adjustment component is disposed on the side path and is configured to change the second polarization direction of the second polarized beam to the first polarization direction.

19. The beam deflection module as described in claim 1, 17, or 18, characterized in that, The polarization direction adjustment device includes a liquid crystal layer and is configured to change the polarization direction of the passing light beam by adjusting the orientation of the liquid crystal molecules within the liquid crystal layer.

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

21. A detection device, characterized in that, The device is configured to perform three-dimensional information detection on objects within a preset detection range, including a beam deflection module as described in any one of claims 1-20. The detection device further 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 objects within the detection range.

22. An electronic device, characterized in that, Including the detection device as described in claim 21, the electronic device further includes an application module configured to perform corresponding functions based on the detection results of the detection device.

Images