Liquid crystal optical phased array based transmit module, lidar, device, and method

Abstract

The application discloses a kind of based on liquid crystal optical phased array emission module, related method and equipment.The method includes controller and several emission units, each emission unit includes light emitting unit, collimating device, polarizing device, LCOPA unit;Light emitting unit is arranged on the focal plane of collimating device;By selecting the light emitting unit light emitting in different emission units on focal plane to obtain the light beam that is propagated along corresponding different directions after LCOPA unit;Collimating device collimates the light beam that light emitting unit emits;Polarizing device adjusts the polarization state of collimated light beam to the same polarization state;LCOPA unit in different emission units is arranged along first direction, and is configured to realize the deflection of multiple consecutive angles in second direction to the light beam that light emitting unit emits;Controller controls the light emitting time of light emitting unit in different emission units and the deflection angle of LCOPA unit to light beam in different emission units.Reduce the high reverse expansion phenomenon of laser scanning, improve sensing accuracy.

Description

Technical Field

[0001] This invention relates to the field of depth sensing technology, and in particular to a transmitting module, lidar, device, and method based on a liquid crystal optical phased array. Background Technology

[0002] LiDAR (Light Detection and Ranging) is a light detection and ranging device that uses infrared lasers to sense the distance to surrounding objects and creates 3D point cloud images by combining the sensed orientation information. LiDAR can be classified in many ways according to different scanning schemes, receiving components, and ranging principles, including mechanical, semi-solid-state, and pure solid-state LiDAR.

[0003] The earliest lidar used a mechanical scanning method, characterized by a vertically arranged laser generator and receiver that rotated 360° driven by mechanical components, allowing for a comprehensive scan of the surrounding environment. The biggest advantage of mechanical lidar is its simple principle and large field of view. However, the separate components result in high costs, and the high-frequency rotation and complex mechanical structure lead to an average failure time of only 1,000-3,000 hours, which is insufficient to meet the minimum 13,000-hour requirement for automotive-grade equipment.

[0004] Semi-solid-state lidar uses rotating mirrors or micromechanical galvanometers (MEMS) to deflect the laser beam for field-of-view scanning. Internally, only the rotating mirror or galvanometer rotates, while the laser and sensor remain stationary. Semi-solid-state lidar offers significantly improved system integration and reduced costs, but its scanning field of view is smaller than that of mechanical lidar (not 360°). Due to the presence of rotating components, its long-term reliability remains relatively low. Furthermore, when the lidar is placed inside a car cabin, the low-frequency noise from its rotation can cause discomfort.

[0005] Solid-state LiDAR has no internal mechanical structure and scans the field of view by deflecting the beam using either a flash or a liquid crystal polarization grating (LCPG). Solid-state LiDAR largely solves the problems associated with mechanical and semi-solid-state LiDAR, meets automotive-grade reliability requirements, and offers advantages such as small size, high integration, and good stability.

[0006] However, current pure solid-state lidar solutions are not yet mature, and the overall cost is also high. Specifically, the main radar has a long ranging range, the floodlight emission requires high power, and large-area array light sources are not feasible. Liquid crystal polarization gratings face the dual problems of slow response speed and low optical efficiency. Furthermore, the large interval between adjacent light deflection angles makes it impossible to directly achieve high light deflection accuracy. Therefore, a large number of light-emitting units are needed to emit beams from different angles to the liquid crystal polarization grating to improve the deflection accuracy of the final projected beam. Summary of the Invention

[0007] In view of the above problems, the present invention is proposed to provide a liquid crystal optical phased array-based emission module, related methods and devices that overcome or at least partially solve the above problems.

[0008] In a first aspect, embodiments of the present invention provide a transmitting module based on a liquid crystal optical phased array, comprising: a controller, a collimating device, a polarizing device, and multiple transmitting units, each transmitting unit comprising a light-emitting unit and a corresponding liquid crystal optical phased array unit;

[0009] The collimating device is used to collimate the light beam emitted by the light-emitting unit;

[0010] The polarization device is used to adjust the polarization state of the light beam emitted by the light-emitting unit before it enters the liquid crystal optical phased array unit.

[0011] The light-emitting unit is disposed on the focal plane of the collimating device; by selecting light-emitting units at different positions on the focal plane to emit light, a scanning beam emitted in different directions after being deflected by the corresponding liquid crystal optical phased array unit is obtained.

[0012] The controller is used to control the light-emitting unit to emit light during the corresponding detection period and to control the deflection angle of the light beam by the corresponding liquid crystal optical phased array unit in the same emitting unit, so as to scan the corresponding sub-region in the field of view.

[0013] In some embodiments, the liquid crystal optical phased array units in the plurality of transmitting units are discretely arranged liquid crystal optical phased array devices; or

[0014] The liquid crystal optical phased array unit in the plurality of transmitting units is a liquid crystal optical phased array region on an integral liquid crystal optical phased array device that can be independently controlled.

[0015] In some embodiments, the plurality of light-emitting units are divided into several light-emitting groups, each light-emitting group including at least one light-emitting unit, and the controller is configured to control the light-emitting units to emit light in the corresponding detection time period according to the divided light-emitting groups, each light-emitting group corresponding to a different detection time period, and the different detection time periods are set sequentially.

[0016] In some embodiments, the light-emitting unit is a light-emitting unit in a planar array light source or a linear array light source.

[0017] In some embodiments, the working period of the liquid crystal optical phased array unit includes a deflection angle adjustment period and a light emission ranging period;

[0018] The controller is configured to control the liquid crystal optical phased array unit to maintain the corresponding light deflection angle unchanged during the light emission ranging period, and to switch the light deflection angle during the deflection angle adjustment period.

[0019] The emission ranging period of the liquid crystal optical phased array unit at least partially overlaps with the detection period of the emission of the corresponding emission unit in the same emission unit.

[0020] In some embodiments, each liquid crystal optical phased array unit corresponding to a light-emitting unit within the same light-emitting group has the same light-emitting ranging period and the same deflection angle adjustment period; or...

[0021] Each liquid crystal optical phased array unit corresponding to a light-emitting unit of a different light-emitting group has a different light-emitting ranging period and a different deflection angle adjustment period.

[0022] In some embodiments, within a detection period corresponding to the same light-emitting group, the light-emitting times of different light-emitting units in the same light-emitting group are not exactly the same.

[0023] In some embodiments, the controller is configured to control the light-emitting unit to emit light pulses in multiple rounds according to a preset time sequence within a corresponding detection period. A detection period includes multiple pulse periods corresponding to multiple rounds of light pulse emission. The controller also controls multiple light-emitting units in the same light-emitting group to emit one light pulse in one pulse period to complete one round of light pulse emission. The light-emitting units in the same light-emitting group emit light pulses at different times in one pulse period.

[0024] In some embodiments, the controller is configured to control that the individual light-emitting units within the same light-emitting group emit light pulses at different times during at least one pulse period.

[0025] In some embodiments, the controller is further configured to control the same light-emitting unit to emit light pulses at times during multiple pulse periods within a detection period, with each pulse period having a corresponding time delay relative to a reference time of its respective pulse period, and the length of the time delay corresponding to each pulse period varying randomly.

[0026] In some embodiments, the pulse period includes a light emission adjustment interval with a preset duration, and the times at which multiple light emission units of the same light emission group emit light pulses within a pulse period are randomly set within the light emission adjustment interval of that pulse period.

[0027] In some embodiments, the timing of the emitted light pulses by multiple light-emitting units in the same light-emitting group within a corresponding detection period is determined in the following manner:

[0028] A set of random number sequences is generated for a pulse period within the corresponding detection period. The random number sequence includes multiple random numbers that correspond one-to-one with multiple light-emitting units. These random numbers serve as the random duration of the delay between the time when each of the multiple light-emitting units emits a light pulse and the reference time of the pulse period. The value of the random duration is greater than or equal to zero and less than or equal to the preset duration of the light emission adjustment interval.

[0029] The timing at which multiple light-emitting units emit light pulses within the pulse period is determined based on the random duration, so as to control the multiple light-emitting units to emit light pulses at randomly set time intervals within the pulse period.

[0030] In some embodiments, the timing of the emitted light pulses by multiple light-emitting units in the same light-emitting group within a corresponding detection period is determined in the following manner:

[0031] A set of random number sequences is generated for each light-emitting unit. The random number sequence includes multiple random numbers that correspond one-to-one with multiple pulse periods of the light-emitting unit within the detection period. These random numbers are used as random durations of the time when the light-emitting unit emits a light pulse within the corresponding pulse period, relative to the reference time of the pulse period. The value of the random duration is greater than or equal to zero and less than or equal to the preset duration of the light emission adjustment interval.

[0032] The timing of light emission by the light-emitting unit within the corresponding multiple pulse periods is determined based on the random duration, so as to control multiple light-emitting units in the same light-emitting group to emit light pulses at randomly set time intervals within a pulse period.

[0033] In some embodiments, within the detection period corresponding to the same light-emitting group, the timing at which at least two light-emitting units emit light pulses within a pulse period has a time difference, and the time difference formed by the at least two light-emitting units in different pulse periods varies randomly.

[0034] In some embodiments, within the detection period corresponding to the same light-emitting group, the times at which multiple light-emitting units of the same light-emitting group emit light pulses within a pulse period form multiple time differences, and the time differences formed by the multiple light-emitting units of the same light-emitting group in different pulse periods vary randomly.

[0035] In some embodiments, within a detection period corresponding to the same light-emitting group, each light-emitting unit in the same light-emitting group has the same light emission time, and the light deflection angles set by each liquid crystal optical phased array unit belonging to the same emission unit as each light-emitting unit in the same light-emitting group are not exactly the same during the detection period.

[0036] In some embodiments, the plurality of light-emitting units are arranged in an array, and the controller is further configured to regard at least a portion of the light-emitting units located in each of the N columns as a light-emitting group; or to regard at least a portion of the light-emitting units located in each of the N rows as a light-emitting group; wherein, N is an integer greater than or equal to 1.

[0037] In some embodiments, the array positions of different light-emitting units in the same row or column within the same light-emitting group are not continuous, and are separated from each other by light-emitting units from at least one other light-emitting group.

[0038] In some embodiments, the light beams emitted by the same light-emitting unit during different detection periods are deflected by the corresponding liquid crystal optical phased array unit at different light deflection angles to correspond to the same scanning partition within the scanning field of view; wherein, each light deflection angle corresponds to scanning a sub-region within the same scanning partition;

[0039] The light beams emitted by different light-emitting units are deflected by the corresponding liquid crystal optical phased array units to correspond to different scanning zones within the scanning field of view.

[0040] In some embodiments, the liquid crystal optical phased array unit is configured as a one-dimensional deflecting beam, and the scanned sub-regions are arranged one-dimensionally along a preset direction within the scanning partition corresponding to the liquid crystal optical phased array; or...

[0041] The liquid crystal optical phased array unit is configured as a two-dimensional deflection beam, and the scanned sub-region is arranged in two dimensions within the scanning partition corresponding to the liquid crystal optical phased array unit.

[0042] In some embodiments, the liquid crystal optical phased array unit is a transmissive liquid crystal optical phased array or a reflective liquid crystal optical phased array.

[0043] In some embodiments, a temperature control device is also included to control the temperature of the liquid crystal optical phased array unit within the normal operating temperature range;

[0044] The temperature control device is a device with heating function; or the temperature control device is a device with both heating and cooling functions.

[0045] In a second aspect, embodiments of the present invention provide a lidar, including a receiving module and a transmitting module as described above. The receiving module includes a plurality of sensing partitions corresponding to a plurality of light-emitting units. The sensing partitions are configured to receive light signals returned from a sub-region scanned by a corresponding light-emitting unit.

[0046] The controller is also used to control the sensing partition to turn on during the detection period of the corresponding light-emitting unit.

[0047] Thirdly, embodiments of the present invention provide an electronic device including the lidar as described above.

[0048] Fourthly, embodiments of the present invention provide a laser radar scanning method based on a liquid crystal optical phased array, implemented through a transmitting module including a collimating device, a polarizing device, and multiple transmitting units. Each transmitting unit includes a light-emitting unit and a corresponding liquid crystal optical phased array unit, wherein the light-emitting unit is disposed on the focal plane of the collimating device; the method includes:

[0049] According to a preset sequence, the light-emitting units at different positions on the focal plane emit light beams during the corresponding detection period. The light beams are collimated by a collimating device and their polarization state is adjusted by a corresponding polarization device before being projected onto the corresponding liquid crystal optical phased array unit.

[0050] The deflection angle of the beam is controlled by the corresponding liquid crystal optical phased array unit to scan the corresponding sub-region in the field of view.

[0051] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0052] The emitting module provided in this invention allows each emitting unit to scan multiple sub-regions at different angles within the field of view in a time-division manner through a corresponding LCOPA unit. Compared to the existing FLASH mode where each emitting unit scans a sub-region at one angle, fewer emitting units are required to scan the entire field of view. Similarly, the LCOPA unit provides finer beam deflection angles than the LCPG. While the LCPG requires multiple emitting units incident from different directions to achieve a finer deflection angle, each LCOPA unit only needs one emitting unit to achieve high-precision angle deflection scanning, requiring fewer emitting units than the LCPG. Therefore, the light source cost of this invention is lower than that of existing technologies. Furthermore, the scanning angle of each LCOPA unit can be independently controlled, allowing for more flexible settings of the scanning order of different emitting units for corresponding angle sub-regions within the field of view.

[0053] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0054] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0055] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0056] Figure 1 This is a schematic diagram of an optional structure of the transmitting module in an embodiment of the present invention.

[0057] Figure 2 This is a schematic diagram of an optional structure of the transmitting module in an embodiment of the present invention.

[0058] Figure 3 This is a schematic diagram of an optional structure of the transmitting unit in an embodiment of the present invention.

[0059] Figure 4 This is a schematic diagram of the structure of a vertically transmissive liquid crystal optical phased array in an embodiment of the present invention.

[0060] Figure 5 This is a schematic diagram of an optional structure of the transmitting unit in an embodiment of the present invention.

[0061] Figure 6 This is a schematic diagram of the structure of the reflective liquid crystal optical phased array in an embodiment of the present invention.

[0062] Figure 7 This is a schematic diagram illustrating the principle of partition scanning in an embodiment of the present invention.

[0063] Figure 8 This is one of the schematic diagrams of the light-emitting unit emitting light in a partitioned manner in an embodiment of the present invention.

[0064] Figure 9 This is the second schematic diagram of the light-emitting unit emitting light in a partitioned manner in an embodiment of the present invention.

[0065] Figure 10 This is a schematic diagram illustrating one timing implementation method according to an embodiment of this application.

[0066] Figure 11 This is a schematic diagram illustrating another timing implementation method according to an embodiment of this application.

[0067] Figure 12 This is a schematic diagram illustrating another timing implementation method according to an embodiment of this application.

[0068] Figure 13 This is a schematic diagram of the structure of the lidar in an embodiment of the present invention.

[0069] Figure 14 This is a flowchart of a laser emission method based on a liquid crystal optical phased array in an embodiment of the present invention.

[0070] Explanation of reference numerals in the attached figures:

[0071] 1. Transmitting unit; 2. Controller; 100. Transmitting module; 200. Receiving module;

[0072] 11. Light-emitting unit; 12. Collimating device; 13. Polarizing device; 14. LCOPA unit;

[0073] 1401, Common electrode layer; 1402, First liquid crystal layer; 1403, Discrete electrode layer; 1404, First glass layer; 1405, Second glass layer;

[0074] 1411, Substrate; 1412, Reflective electrode layer; 1413, First alignment layer; 1414, Second liquid crystal layer; 1415, Second alignment layer; 1416, ITO electrode layer; 1417, Third glass layer; 1418, Fourth glass layer. Detailed Implementation

[0075] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0076] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0077] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0078] To address the issues of high-frequency dilation that exist in existing solid-state lidar scanning technologies, the inventors of this application conducted an in-depth study on the reasons why lidar is prone to "high-reflectivity dilation" when sensing highly reflective targets. They discovered that this is mainly due to the strong reflection and scattering effect of high-reflectivity objects on laser light. The reflected light is too strong and scatters in the receiving lens, causing pixels near the receiving pixel corresponding to the target object to also receive stray light of considerable intensity. After processing, this is displayed as a point cloud of objects at the same distance.

[0079] Since scattering is unavoidable, the inventors of this application have discovered that reducing the number of pixels working simultaneously and maximizing the distance between pixels working simultaneously can effectively mitigate the impact of "high back-expansion". Based on this, this invention provides a solution for the high back-expansion problem of pure solid-state lidar by using a liquid crystal optical phased array combined with a light source partitioning emission.

[0080] The solution provided in this application uses a light source partitioning emission scheme combined with a liquid crystal optical phased array to achieve ranging scanning in the vertical and horizontal directions of a pure solid-state main radar. It achieves high angular resolution while satisfying a wide field of view. This scheme can replace the mechanical rotating components in semi-solid-state lidar, improving the radar's stability. The emission scheme using a light source partitioning emission scheme combined with a liquid crystal optical phased array provided in this application can meet the scanning requirements of pure solid-state lidar, achieving sufficient beam deflection angle and covering a sufficient scanning range while solving the problem of high back-expansion.

[0081] Liquid Crystal Optical Phased Array (LCOPA) is a technique that utilizes the electro-optic properties of liquid crystal materials to achieve precise beam deflection. It modulates a laser beam using the birefringence effect of the liquid crystal material, altering the rotational state of the liquid crystal molecules by changing the applied electric field. This alters the refractive index of the liquid crystal, creating optical path differences and phase differences between different unit beams, ultimately achieving the reconstruction and precise control of the array beam's isophase planes. LCPPA offers advantages such as low-voltage chip driving, megapixel array design, large-aperture effective modulation, fast liquid crystal material response, wide optical band operation, ultra-low power consumption, and ultra-small size and weight. Compared to OPA based on silicon photonics technology, it is more mature and has higher optical efficiency.

[0082] This invention provides a transmitting module based on a liquid crystal optical phased array, the structure of which is as follows: Figure 1 and Figure 2 As shown, it includes: a controller 2, a collimating device 12, a polarizing device 13 and several emitting units 1, each emitting unit 1 including a light-emitting unit 11 and a corresponding liquid crystal optical phased array (LCOPA) unit 14;

[0083] The light-emitting unit 11 is disposed on the focal plane of the collimating device 12; by selecting the light-emitting unit in different emitting units on the focal plane to emit light, a beam of light propagating in different directions after passing through the LCOPA unit is obtained;

[0084] Collimation device 12 is used to collimate the light beam emitted by light-emitting unit 11;

[0085] Polarizing device 13 is used to adjust the polarization state of the collimated beam to the same polarization state;

[0086] The LCOPA units 14 in different emitting units 1 are arranged along the first direction and configured to deflect the light beam emitted by the emitting unit 11 at multiple consecutive angles in the second direction.

[0087] The controller 14 is used to control the light emission time of the light-emitting unit 11 in different emitting units 1, and to control the deflection angle of the light beam by the LCOPA unit 14 in different emitting units 1.

[0088] In some optional embodiments, the above-mentioned transmitting module, wherein the collimating device, polarizing device, and LCOPA unit in different transmitting units can be designed separately or as a single unit. For example, optionally, the LCOPA unit 14 in several transmitting units 1 are discretely arranged LCOPAs, or the LCOPA unit 14 in several transmitting units 1 is a single integrated LCOPA; optionally, the collimating device 12 in several transmitting units 1 are discretely arranged collimating lenses, or the collimating device 12 in several transmitting units 1 is a single integrated collimating lens; optionally, the polarizing device 13 in several transmitting units 1 are discretely arranged polarizers, or the polarizing device 13 in several transmitting units 1 is a single integrated polarizer.

[0089] in Figure 1 Taking the split design as an example, Figure 2 Take integrated design as an example. In practical applications, some components can be designed separately, while others can be designed as a single unit. For example, collimation devices can be designed as a single unit, while LCOPA units can be designed separately. Different combinations of designs can be chosen according to the actual application requirements.

[0090] In some optional embodiments, multiple light-emitting units in the above-described emission module together constitute a light source, which can be a planar array light source or a linear array light source. Each light-emitting unit can be one or more light-emitting units in a planar array light source or a linear array light source. To further reduce the high-reflection expansion problem, the emission time of the light-emitting units can be controlled so that, within a detection period, the emission times of at least two adjacent light-emitting units are different.

[0091] Optionally, when a light-emitting unit includes a light-emitting unit, a corresponding light-emitting unit includes an LCOPA unit; each LCOPA unit deflects the light beam emitted by the light-emitting unit at multiple consecutive angles in the second direction to achieve continuous scanning in the second direction, and achieves continuous scanning in the first direction by emitting light through multiple arranged light-emitting units respectively.

[0092] When a light-emitting unit includes more than one light-emitting unit, correspondingly, an emitting unit also includes more than one LCOPA unit. One light-emitting unit is paired with one LCOPA unit, and the LCOPA units in the same emitting unit are arranged along the second direction. Each LCOPA unit deflects the light beam emitted by the light-emitting unit at multiple consecutive angles in the second direction, achieving continuous scanning of a portion of the region in the second direction. Continuous scanning in the second direction is achieved through multiple light-emitting units arranged in the same emitting unit, while continuous scanning in the first direction is achieved by the multiple light-emitting units emitting light separately.

[0093] In some optional embodiments, the LCOPA unit in the above-mentioned transmitting module can adopt different types of LCOPA, such as, but not limited to, vertical transmission liquid crystal optical phased array, reflective liquid crystal optical phased array, etc.

[0094] Optional, see Figure 3 The transmitting unit shown is an example of a vertically transmissive liquid crystal optical phased array. An exemplary structure of a vertically transmissive liquid crystal optical phased array can be found in [reference needed]. Figure 4 As shown, the structure includes a common electrode layer 1401, a first liquid crystal layer 1402, and a discrete electrode layer 1403 comprising multiple discrete electrodes arranged sequentially. By applying different voltages to different discrete electrodes, the liquid crystal molecules in the liquid crystal regions corresponding to different discrete electrodes rotate at different angles, thereby enabling different liquid crystal regions to achieve different deflection angles for the unit beam. By modulating the deflection angles of multiple unit beams in the beam, the deflection angle of the beam in the LCOPA unit is controlled. Optionally, glass protective layers can be provided outside the two electrode layers, such as a first glass layer 1404 above the common electrode layer 1401 and a second glass layer 1405 below the discrete electrode layer 1403.

[0095] The deflection angle of the beam by the above-mentioned vertical transmission liquid crystal optical phased array is θ=arcsin(ΔL / W), where ΔL is the optical path difference between adjacent unit beams, and W is the distance between two adjacent discrete electrodes; where ΔL=d*Δn, d is the thickness of the liquid crystal layer in LCOPA, and Δn is the refractive index difference between the liquid crystal units corresponding to two adjacent discrete electrodes; correspondingly, the phase difference between adjacent unit beams is: ΔΦ / 2π=ΔL / λ=2d*Δn / λ.

[0096] See Figure 3 As shown, the liquid crystal layer consists of two layers of glass and two layers of electrodes. The upper electrode is a common electrode layer covering the entire surface, typically made of ITO material. The lower electrode is a discrete electrode layer composed of multiple discrete electrodes, which can modulate the liquid crystal in different regions to achieve different deflection angles of the light beam. Specifically, by applying different voltage values ​​to different discrete electrodes, the rotation of liquid crystal molecules in different regions is different, and the refractive index changes accordingly, thus resulting in different final deflection angles of the light beam.

[0097] Initially, the liquid crystal in each region is in a flat state. When a voltage is applied to some discrete electrodes, the liquid crystal molecules rotate. Different voltages cause the liquid crystal molecules to rotate at different angles, thus changing the state of the liquid crystal molecules in the regions corresponding to different discrete electrodes. The time it takes for the liquid crystal molecules to reach a stable state after rotation following the application of voltage is called the liquid crystal reversal time.

[0098] Each discrete electrode of an LCOPA unit corresponds to a liquid crystal region that can deflect one unit of the incident beam, ultimately achieving deflection of the entire incident beam. An LCOPA has multiple discrete electrodes, and the liquid crystal molecules in the liquid crystal region corresponding to each discrete electrode can be flipped to any angle, not limited to parallel or perpendicular. The deflection of liquid crystal molecules in different regions can be different. For an LCOPA unit (or a section corresponding to one light-emitting unit in an integrated LCOPA unit), the more electrodes, the more precise the control of the beam deflection angle, and the higher the accuracy of the deflection angle.

[0099] See Figure 4 As shown, when a beam of light is incident on an LCOPA cell, different discrete electrodes within the LCOPA cell correspond to different unit beams, such as unit beams 1, 2, 3, 4, 5, 6, 7, and 8 in the figure. Assuming the liquid crystal layer thickness of the LCOPA cell is d, and the refractive index difference between the liquid crystal regions corresponding to adjacent discrete electrodes is Δn, then the optical path difference between adjacent unit beams is ΔL = d * Δn, corresponding to a phase difference ΔΦ / 2π = ΔL / λ = d * Δn / λ. According to Huygens wave theory, the outgoing light direction is an equiphase surface; therefore, the outgoing angle θ = arcsin(ΔL / W) can be calculated from the pitch W of the discrete electrodes, where W is the distance to the two adjacent discrete electrodes. The final deflection direction of the beam is related to the sign of the phase difference. For example, Figure 4 The phase of beam 2 in the middle unit is greater than the phase of beam 1 after passing through the liquid crystal. At this time, the phase difference is positive, that is, ΔΦ is positive. Therefore, the beam is deflected to the right after passing through the LCOPA to satisfy the equiphase surface. Similarly, if ΔΦ is negative, the emitted beam is deflected to the left.

[0100] Figure 4The LCOPA unit has eight discrete electrodes, corresponding to eight unit beams. The phases of unit beams 1, 2, 3, 4, 5, 6, 7, and 8 are π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, and 2π, respectively. The phase difference of the eight unit beams is combined to form a larger beam, which is the output beam. Adjusting the phase difference of each unit beam and the mixing effect determines the overall direction of the output beam. In other words, the voltages of the eight partitioned electrodes work together to achieve the final deflection direction of the incident beam, resulting in the final output beam.

[0101] It is worth noting that the discrete unit beams indicated by the red arrows in the diagram are for illustrative purposes only. In reality, the same collimated and polarized beam with a larger diameter is perpendicularly incident on the liquid crystal phased array to satisfy the coherence of the interference. Therefore, the actual optical path is as follows: laser light is emitted from the source laser, passes through the collimating lens and polarizer, and then incident on the LCOPA for deflection. (See [link to LCOPA deflection process]). Figure 3 As shown. The incident beam of the LCOPA unit can be incident perpendicularly or obliquely. The light-emitting unit is set at the focal plane of the collimating lens, and the light-emitting unit can be the light-emitting unit in a two-dimensional light source.

[0102] In the aforementioned transmitting unit, LCOPA is used to achieve beam deflection. Since LCOPA has phase requirements, the phase design will be different if different polarized light is incident. If there are several types of polarized light and they are not modulated by a polarizer, the phase of the unit beam may be different, which means that LCOPA cannot be modulated with a single phase. Therefore, for cases with different polarization directions, a polarizer is needed to adjust the polarization state to make it uniform.

[0103] Optional, see Figure 5 The transmitting unit shown is an example of a reflective liquid crystal optical phased array. An exemplary structure of a reflective liquid crystal optical phased array can be found in [reference needed]. Figure 6 As shown,

[0104] The reflective liquid crystal optical phased array includes a substrate 1411, a reflective electrode layer 1412 comprising several discrete electrodes, a first alignment layer 1413, a second liquid crystal layer 1414, a second alignment layer 1415, and an ITO electrode layer 1416 arranged sequentially. By applying different voltages to different discrete electrodes, the liquid crystal molecules in the liquid crystal regions corresponding to different discrete electrodes rotate at different angles, thereby enabling different liquid crystal regions to achieve different reflection angles of the unit beam. By modulating the deflection angles of multiple unit beams in the beam, the deflection angle of the beam in the LCOPA unit is controlled. Optionally, glass protective layers can be respectively provided outside the two electrode layers, such as a third glass layer 1417 above the ITO electrode layer 1416 and a fourth glass layer 1418 below the substrate 1411.

[0105] The working principle of a reflective liquid crystal optical phased array (LCD) differs from that of a vertically transmitting LCD. In a reflective LCD, the incident light beam is fed back through reflective electrodes, passing through the liquid crystal layer twice. (See also...) Figure 6 As shown, V1 and V2 are two discrete electrodes in the reflective electrode array, and they also function as reflectors. Since the light beam passes through the liquid crystal twice from incident to exit, the optical path difference between adjacent unit beams is correspondingly doubled. Therefore, the deflection angle θ of the light beam in the above-mentioned reflective liquid crystal optical phased array is θ = arcsin(ΔL / W), where ΔL is the optical path difference between adjacent unit beams, and W is the distance between two adjacent discrete electrodes; the optical path difference between adjacent unit beams ΔL = 2d * Δn, where d is the thickness of the liquid crystal layer in the LCOPA, and Δn is the difference in refractive index between the liquid crystal units corresponding to the two adjacent discrete electrodes; correspondingly, the phase difference between adjacent unit beams is: ΔΦ / 2π = ΔL / λ = 2d * Δn / λ. In the figure, Lin represents the incident light, and Lou represents the reflected light.

[0106] LCOPA is an active type with electrodes on both sides, allowing for phase control of each liquid crystal region. Therefore, the deflection angle can be continuously varied. Compared to LCPG, it enables continuous angle adjustment, accommodating both large and small angle deflections in practical applications, thus achieving a wider range of angle variations and greater angular resolution. When used in lidar, this emission module enables more precise scanning, supporting both coarse and fine scans. A single emitting unit can continuously scan multiple positions, and a single emitting unit can include one or more emitting units, significantly reducing the number of emitting units in the light source.

[0107] The response speed of liquid crystal materials is typically on the order of milliseconds. Each deflection at a different angle requires a new voltage to drive the liquid crystal molecules. Therefore, at a frame rate of 10Hz, the number of angles a single LCOPA can deflect is limited. To address this, a single scan (single deflection angle) usually involves emitting a large light spot and enabling multiple pixels to work simultaneously, such as multiple rows or columns of pixels working together, to reduce the number of light deflections required for a single frame measurement. However, this exacerbates the high-reflection dilatation phenomenon.

[0108] This application proposes a liquid crystal phased array (LCD) partitioned emission scheme to address high reflection dilatation. It divides simultaneously operating pixels into multiple partitions based on spatial relationships, with pixels within the same partition spatially clustered and continuous. To achieve this, the system requires multiple sets of light-emitting units as light sources, combined with an LCOPA (Liquid Crystal Optical Amplifier) ​​to realize partitioned emission. During reception, pixels at specific locations on the SPAD (Semiconductor Display Panel) chip are activated one-to-one. As mentioned above, a single emission unit can utilize an independent collimating lens, polarizer, and LCOPA unit, for example... Figure 1 As shown in the diagram. Multiple transmitting units can also share an integrated collimating lens, polarizer, and LCOPA unit, for example... Figure 2 As shown in the diagram, each emitting unit can independently control the emission time, optical power, pulse width, and optical deflection angle of its emitting unit. Figure 1 and Figure 2 The diagram illustrates a scenario where four groups of emitting units can emit light in separate zones. Each group can independently control the emission time of its light source. Although the emitting units shown in the diagram are discrete light sources, the light source could also be a large-area array or a linear array, with each region (i.e., each unit) operating independently. Similarly, an LCOPA unit could be a single area array or a linear array, with each region operating independently.

[0109] See Figure 7 In the illustrated embodiment, each light-emitting unit is called a zone light source. The light beam emitted by the zone light source is deflected by a corresponding LCOPA unit to scan the corresponding scanning zone within the field of view. Moreover, a zone light source can switch between scanning different scanning zones by changing the deflection angle of the light beam by the LCOPA unit at different times. Eight zone light sources correspond to eight scanning zones within the scanning field of view. The eight scanning zones are arranged from top to bottom along a first direction (shown as vertical in the figure), and the eight zone light sources are also arranged along the first direction. Multiple sub-zones within a scanning zone are arranged along a second direction (shown as horizontal in the figure). By controlling the deflection angle of the LCOPA in the emitting unit, scanning is performed one by one.

[0110] To further reduce high-reverse expansion, the emission time of each light-emitting unit can be controlled so that the emission times of two adjacent light-emitting units are as different as possible.

[0111] See Figure 8 and Figure 9 As shown, the LCOPA of the above-mentioned transmitting module is configured to include a deflection angle adjustment period and a light emission ranging period;

[0112] The controller is configured to control the liquid crystal optical phased array unit to maintain the corresponding light deflection angle unchanged during the light emission ranging period, and to switch the light deflection angle during the deflection angle adjustment period.

[0113] The emission ranging period of the liquid crystal optical phased array unit at least partially overlaps with the detection period of the emission of the corresponding emission unit in the same emission unit.

[0114] Each light-emitting unit emits light during the light emission ranging period. The LCOPA deflects the light beam during the light emission ranging period. During the deflection angle adjustment period, the deflection angle of the LCOPA unit on the light beam is changed by changing the voltage applied to the electrodes on both sides of the LCOPA.

[0115] In some optional embodiments, the emission ranging time period and the deflection angle adjustment time period are the same for each LCOPA unit. Correspondingly, the detection time period for each emission unit is the same, and the detection time period for each emission unit corresponds to the laser ranging time period of the corresponding LCOPA unit; see [link to documentation]. Figure 8 As shown, taking the four LCOPA units corresponding to the four light-emitting units as an example, the deflection angle adjustment periods of the four LCOPA units are synchronously aligned, and the light emission ranging periods are also synchronously aligned.

[0116] In some optional embodiments, at least two LCOPA units have different emission ranging periods, at least two LCOPA units have different deflection angle adjustment periods, and correspondingly, at least two emission units have different detection periods. Each emission unit's detection period corresponds to the laser ranging period of its corresponding LCOPA unit. See also Figure 9 As shown, taking the four LCOPA units corresponding to the four light-emitting units as an example, the deflection angle adjustment periods of the four LCOPA units are staggered in time, and the light emission ranging periods are also staggered in time.

[0117] When the above-mentioned emission module scans the field of view, completing one scan of the field of view can be regarded as a detection frame. A detection frame includes multiple detection periods, and a detection period includes multiple pulse periods corresponding to multiple light pulses. One light pulse is emitted in one pulse period. Several light-emitting units start emitting light at the same time in one pulse period; or the time when the light-emitting unit starts emitting light in one pulse period is delayed by a random time relative to the start time of the pulse period. At least two light-emitting units emit light pulses at different times in one pulse period.

[0118] Optionally, the light-emitting units emit light pulses at different times within at least one pulse period. For example... Figure 9 As shown, by configuring the pulse emission times of each light-emitting unit to be different, the mutual interference of the received beams of adjacent receiving units in the receiving array can be avoided as much as possible, thereby minimizing the occurrence of high back expansion phenomenon.

[0119] See Figure 7 As shown, the field of view can be divided into several scanning zones, which are arranged along a first direction, and several sub-zones within each scanning zone are arranged along a second direction. One light-emitting unit corresponds to scanning one scanning zone. The light beam emitted by the same light-emitting unit during different detection periods is deflected at different angles by the LCOPA unit and then projected onto several sub-zones of the same scanning zone within the field of view. Figure 7 The small squares in the image; different light-emitting units emit light separately during the same detection period and are deflected by the LCOPA unit at the same or different angles to be projected onto different scanning zones within the field of view. For example Figure 7 In this process, different scanning zones are scanned within a single detection period. The light beams emitted by different light-emitting units can scan sub-zones corresponding to different positions within those scanning zones. For example... Figure 7 One column in the array; it can also scan sub-partitions in different locations within different scan partitions, for example... Figure 7 The gray squares in the middle.

[0120] In some embodiments, the light beams emitted by the same light-emitting unit during different detection periods are deflected by the corresponding liquid crystal optical phased array unit at different light deflection angles to correspond to the same scanning partition within the scanning field of view; wherein, each light deflection angle corresponds to scanning a sub-region within the same scanning partition; the light beams emitted by different light-emitting units are deflected by the corresponding liquid crystal optical phased array unit to correspond to different scanning partitions within the scanning field of view.

[0121] In some embodiments, the liquid crystal optical phased array unit is configured as a one-dimensional deflected beam, and the scanned sub-regions are arranged one-dimensionally along a preset direction within the scanning partition corresponding to the liquid crystal optical phased array; or, the liquid crystal optical phased array unit is configured as a two-dimensional deflected beam, and the scanned sub-regions are arranged two-dimensionally within the scanning partition corresponding to the liquid crystal optical phased array unit.

[0122] In some embodiments, the above-mentioned transmitting module further includes a temperature control device, which encloses the LCOPA unit and is used to control the temperature of the LCOPA unit within the normal operating temperature range; the temperature control device is a device with heating function; or the temperature control device is a device with both heating and cooling functions.

[0123] In one possible implementation, the multiple light-emitting units of the emitting module can be divided into several light-emitting groups. A controller can be used to control the light-emitting units in each light-emitting group to emit light pulses in a preset order within their respective detection time periods. Each light-emitting group corresponds to a different detection time period, and these different detection time periods are set sequentially. Within the detection time period corresponding to the same light-emitting group, the light-emitting units in that group emit light pulses at different times. The controller is configured to control the light-emitting units to emit light pulses in multiple rounds according to a preset time sequence within the corresponding detection time period. One detection time period includes multiple pulse periods corresponding to multiple rounds of light pulse emission. The controller also controls multiple light-emitting units in the same light-emitting group to emit one light pulse in one pulse period to complete one round of light pulse emission. The different light-emitting units within the same light-emitting group emit light pulses at different times within one pulse period.

[0124] Within a detection period corresponding to the same light-emitting group, each light-emitting unit in the same light-emitting group has the same light emission time, and the light deflection angles set by each liquid crystal optical phased array unit belonging to the same emission unit as each light-emitting unit in the same light-emitting group are not exactly the same within the detection period.

[0125] The plurality of light-emitting units are arranged in an array, and the controller is further configured to regard at least a portion of the light-emitting units located in each of the N columns as a light-emitting group; or to regard at least a portion of the light-emitting units located in each of the N rows as a light-emitting group; wherein, N is an integer greater than or equal to 1.

[0126] The array positions of different light-emitting units in the same row or column within the same light-emitting group are not continuous, and are separated from each other by light-emitting units from at least one other light-emitting group.

[0127] The method of controlling the light-emitting units in each light-emitting unit to emit light pulses in a preset order during corresponding detection time periods includes: controlling multiple light-emitting units in the same light-emitting group to emit multiple rounds of light pulses in a preset time sequence during the corresponding detection time periods. Each detection time period includes multiple pulse segments corresponding to the multiple rounds of light pulse emission. Each light-emitting unit emits one light pulse within one pulse segment to complete one round of light pulse emission. At least two light-emitting units emit light pulses at different times within one pulse segment. Further optionally, the method controls that each light-emitting unit emits light pulses at different times within at least one pulse segment.

[0128] Specifically, one light-emitting unit corresponds to one detection period. During the first detection period, multiple light-emitting units in the first light-emitting group emit light in parallel; during the second detection period, the light-emitting units of the second light-emitting unit emit light in parallel; during the Nth detection period, the light-emitting units of the Nth light-emitting unit emit light in parallel. And so on, with each light-emitting unit emitting light serially in a preset order.

[0129] For each detection period, the emission pulse times of at least two light-emitting units in the light-emitting unit are different. The reset time of the matching quenching circuit is used to ensure that the corresponding pixel blocks do not interfere with each other when collecting sensing information, so as to ensure that the reflected signal corresponds one-to-one with the emitted pulse.

[0130] Reference Figure 10 The emission timing diagram shown is as follows. Figure 10 In the process, the light-emitting unit of the emitting module is divided into N light-emitting units, referred to as group 1 to group N. Figure 10 The square wave waveforms in the timing diagrams labeled as light-emitting units 1 to N represent the detection periods of the first group (called the first detection period), the detection periods of the second group (called the second detection period), ... the detection periods of the Nth group (called the Nth detection period), respectively; the pulse signals in the timing waveforms of light-emitting units numbered 1 to M represent the light pulses emitted by light-emitting units numbered 1 to M, respectively.

[0131] During these N detection periods, the light-emitting units of each group are always powered on during the corresponding detection period, but only emit light when emitting light pulses.

[0132] Within the detection period corresponding to each light-emitting group, each light-emitting unit in that group will emit multiple rounds of light pulses, with each round of emission occurring within a pulse period (denoted by T). (Refer to...) Figure 10 As shown, during the detection period corresponding to the pulse waveform of the first group, M light-emitting units emit light in multiple different pulse periods (using T1 to T2). num Within a given pulse period (T1), multiple light pulses (let's say num) are emitted. Different ranging periods are indicated by dashed lines. For example, in the first pulse period T1, each of the M emitting units emits one light pulse (i.e., lights up once). In the second pulse period T2, each of the M emitting units emits another light pulse, and so on. It should be understood that within a single pulse period, one or more of the M emitting units may not emit light. The number of times a emitting unit emits light within a single unit can be determined based on factors such as the pixel count and ranging frame rate of the applicable lidar.

[0133] Within each pulse period, the timing of light pulse emission by multiple light-emitting units in the light-emitting group can be randomly set. This random setting achieves the effect of counting and diverging crosstalk signals. To ensure sufficient flight time for the light pulses within the ranging range, the beginning of each pulse period has a preset duration of light emission adjustment interval. Within this preset adjustment interval, the multiple light-emitting units in the same light-emitting group randomly set their respective light pulse emission times. In other words, the timing of light pulse emission by multiple light-emitting units in the same light-emitting group within a single pulse period is randomly set within the light emission adjustment interval of that pulse period.

[0134] The light emission adjustment interval is located at the beginning of the pulse period and has a preset duration, for example, its duration is set to the upper limit of the time delay between the time of light pulse emission and the start time of the pulse period.

[0135] Optionally, the controller is used to control the time when the same light-emitting unit emits light pulses in multiple pulse periods within a detection period, with a corresponding time delay relative to the reference time of each pulse period, and the length of the time delay corresponding to each pulse period varies randomly.

[0136] There are several ways to randomly set the timing of light pulse emission. For example, within the light emission adjustment range of a pulse period, the timing of light pulse emission by multiple light-emitting units of the same light-emitting group is randomly set during that pulse period.

[0137] Within a single pulse of light emission duration, some light-emitting units in the same light-emitting group may emit light at the same time, while others may emit light at different times. Alternatively, within a single pulse, the emission times of each light-emitting unit in the same group may be different from each other.

[0138] Based on this, refer to Figure 10 As shown, within each pulse period of the same light-emitting group, the timing of the light pulses emitted by different light-emitting units can be different. The controller is configured to control that the timing of the light pulses emitted by each light-emitting unit in the same light-emitting group is different within at least one pulse period. By staggering the emission times of each light-emitting unit, the crosstalk signals between different light-emitting units are dispersed, thus solving the problem of crosstalk between multiple light-emitting units.

[0139] Alternatively, within a certain pulse period of the same light-emitting group, among the M light-emitting units, some units emit light pulses at different times (the majority), while other units emit light pulses at the same time. That is... Figure 10During a certain pulse period, the starting time of the emitted light pulses corresponding to the light-emitting units numbered 1 to M may be different for some light-emitting units, while the starting time of the emitted pulses for some light-emitting units may be the same.

[0140] In one embodiment, within the detection period corresponding to the same light-emitting group, there may also be instances where the time at which the same light-emitting unit emits light pulses during at least two pulse periods has the same time interval relative to the start time of each pulse period.

[0141] In this embodiment, for a certain light-emitting unit, for example... Figure 10 For the light-emitting unit corresponding to number 1 in the diagram, the time at which the light-emitting unit emits a light pulse in each pulse period, relative to the start time of that pulse period (T1~T in the diagram), is... num The time intervals (shown by the dashed lines in the diagram) can all be different, or they can be from T1 to T2. num Within a portion of the pulse period, the time intervals relative to the start time of that pulse period are different from each other, while within another portion of the pulse period, the time intervals relative to the start time of that pulse period are the same from each other.

[0142] In one embodiment, the controller of the lidar is further configured to control a light-emitting unit to emit multiple light pulses within a detection period corresponding to the light-emitting unit, wherein the multiple light pulses have a randomly set time interval.

[0143] Reference Figure 10 As shown, viewed laterally from a certain light-emitting unit, its temperature ranges from T1 to T2. num The light pulses were emitted num times, and the time interval between these light pulses could be randomly generated.

[0144] The specific method for randomly setting the time of emitting light pulses can also be that the emission time of each light-emitting unit is different within one of the pulse periods, and the emission times of different light-emitting units form a time difference with each other; furthermore, corresponding to different pulse periods, the time difference formed between the emission times of at least two different light-emitting units in the same light-emitting group can be randomly varied, and the variation range is within the light emission adjustment range.

[0145] In one embodiment, within the detection period corresponding to the same light-emitting group, the times at which at least two light-emitting units emit light pulses within a pulse period have a time difference, and the time difference formed by the at least two light-emitting units in different pulse periods varies randomly.

[0146] In one embodiment, within the detection period corresponding to the same light-emitting group, the times at which multiple light-emitting units of the same group emit light pulses within a pulse period form corresponding time differences. These time differences between the multiple light-emitting units in different pulse periods vary randomly. Unlike the previous embodiment, where the time differences between at least two light-emitting units in different pulse periods varied randomly, implying that some light-emitting units might have equal time differences in different pulse periods, in this embodiment, the time differences between multiple light-emitting units emitting light pulses within a pulse period within the same light-emitting group are randomly varied. That is, the time difference between the times when multiple light-emitting units emit light pulses in the previous pulse period may be different from the time difference between the times when multiple light-emitting units emit light pulses in the next pulse period.

[0147] The time difference between the times when the light pulses are emitted by the multiple light-emitting units mentioned above refers to the time difference between the emission times of any two light-emitting units in the same light-emitting group within the same ranging period (the time difference is a value greater than or equal to zero, i.e., the value obtained by subtracting the earlier emission time from the later emission time).

[0148] For example, within a certain pulse period of the detection time of the same light-emitting group, from a longitudinal perspective, there is a time difference between the light pulses emitted by different light-emitting units. (This is still referred to as...) Figure 10 As shown, for example, the light-emitting units numbered 1 to M can have a time difference with each other during the time period T1, and moreover, during T1, T2...T num The time difference between these light-emitting units varies randomly during different pulse periods. That is, the time difference between each light-emitting unit in T1 may be different from the time difference between these light-emitting units in T2 and T3.

[0149] The aforementioned time difference may also result in some pulse periods being the same, while other pulse periods are different; as long as it satisfies the requirement of random variation.

[0150] In one embodiment, in order to facilitate the determination of the light emission time of the light-emitting unit within each pulse period, in this embodiment of the invention, the random variation range of the above-mentioned time difference is greater than or equal to zero and less than or equal to the preset duration of the light emission adjustment interval.

[0151] The specific method for randomly setting the timing of the emitted light pulses can also be as follows: for a certain light-emitting unit, the emission time of the light-emitting unit is different in each pulse period of a detection period; or the emission time of the light-emitting unit is the same in some pulse periods of a detection period, while the emission time is different in other pulse periods (satisfying the random condition).

[0152] The timing of light pulses emitted by multiple light-emitting units in the same light-emitting group during the pulse period can be randomly set. Correspondingly, the delay time of light pulses emitted by multiple light-emitting units in a pulse period relative to the start time of the pulse period can be determined by generating random numbers.

[0153] Specifically, in one embodiment, the lidar controller is configured to determine the timing of light pulse emission from multiple light-emitting units of the same light-emitting group within a corresponding detection period by means of:

[0154] A set of random number sequences is generated for each pulse period. The random number sequence includes multiple random numbers that correspond one-to-one with multiple light-emitting units. These random numbers serve as the random duration of the time when each of the multiple light-emitting units emits a light pulse within the pulse period, relative to the start time of the pulse period. The value of the random duration is greater than or equal to zero and less than or equal to the preset duration of the light emission adjustment interval.

[0155] The timing at which multiple light-emitting units emit light pulses within the pulse period is determined based on a random duration, so as to control the multiple light-emitting units to emit light pulses correspondingly within the pulse period.

[0156] In this embodiment, a random sequence is generated and assigned a value independently for each pulse period of each light-emitting unit before each pulse period.

[0157] That is, before each pulse period, a corresponding random number sequence is generated for the corresponding pulse period, and then each random number in the random number sequence is assigned to the random duration of the light pulse delay emitted by each light-emitting unit 1 within the pulse period.

[0158] The method of generating corresponding random sequences independently for different pulse periods may result in overlap of random numbers generated in different pulse periods. That is, the following may be possible: within different ranging durations, the random durations corresponding to the same light-emitting unit or different light-emitting units may be equal, but most light-emitting units 111 can satisfy the condition that the random durations are not equal within the same ranging duration or within different ranging durations.

[0159] In other embodiments, a random sequence of random durations corresponding to all pulse periods within the detection period can be generated and assigned values ​​at once.

[0160] Specifically, the lidar controller is configured to generate multiple sets of random number sequences at once for multiple pulse periods corresponding to the detection period, and before each pulse period, determine the time when the multiple light-emitting units emit light pulses respectively in that pulse period based on one of the random number sequences.

[0161] Alternatively, for multiple pulse periods, a random number sequence containing the delay duration of each light-emitting unit across all pulse periods can be pre-generated. Figure 10 For example, a random number sequence containing M×num random numbers can be pre-generated, and each data point in this random number sequence can be assigned to, for example... Figure 10 Each light-emitting unit 1 to M in the middle is in T1 to T num The random durations of the intermediate delay.

[0162] After assigning the value, you can use the corresponding random duration in different pulse periods.

[0163] In one embodiment, a random number sequence can be generated independently for each pulse period of each emitting unit. Specifically, the lidar controller is configured to determine the timing of the emitted light pulses of multiple emitting units in the same emitting group within the corresponding detection period in the following manner:

[0164] A set of random number sequences is generated for each light-emitting unit. The random number sequence includes multiple random numbers that correspond one-to-one with multiple pulse periods of the light-emitting unit. These random numbers are used as random durations of the time when the light-emitting unit emits a light pulse within the corresponding pulse period, relative to the start time of the pulse period. The random duration ranges from greater than or equal to zero to less than or equal to the preset duration of the light-emitting adjustment interval.

[0165] The timing of the light-emitting unit emitting light pulses within the corresponding multiple pulse periods is determined based on the random duration, so as to control the light-emitting unit to emit light pulses sequentially within the multiple pulse periods.

[0166] The embodiments of the present invention are not limited to the method of generating random number sequences, nor to the specific implementation of assigning random number sequences to random durations.

[0167] Figure 10 The random duration of medium delay is displayed through a grid, from Figure 10 As can be seen from both horizontal and vertical perspectives, during the detection period of Group 1, each emitting unit exhibits different pulse durations from T1 to T2. num Each random duration of the intermediate delay can be randomly generated.

[0168] The controller can control the random duration corresponding to the time when each light-emitting unit emits a light pulse, starting from the reference time of the pulse period, for each pulse period, so as to obtain the time when each light-emitting unit emits a light pulse within the pulse period.

[0169] Taking the first pulse period T1 as an example, during the first pulse period, the time when the light-emitting units numbered 1, 2, ... M emit light pulses is delayed by a random duration relative to the start time of T1. The magnitude of the random duration of the delay is represented by grid lines, and the width of the grid lines represents the length of the random duration.

[0170] Because the delay time of the light-emitting unit relative to the start time of the pulse period varies randomly within the pulse period, the timing of the light pulse emitted by the light-emitting unit within the pulse period also varies randomly. Figure 12 It can be seen that in the first group, the time when each light-emitting unit numbered 1 to M emits a light pulse is randomly changed within the same pulse period, and / or, in the entire detection period of the first group, the time when the light-emitting unit emits a light pulse is also randomly changed within each pulse period.

[0171] The generation of the above-mentioned random number sequence can refer to existing random number generation methods. Common random number generation methods include the following: pseudo-random number generation algorithms, such as linear congruential methods, which simulate random number sequences through a deterministic calculation process or use physical phenomena (such as thermal noise, radioactive decay, etc.) to generate real random numbers, etc. The embodiments of this invention do not limit this.

[0172] For the same light-emitting group, the delay duration of each light-emitting unit in each pulse period can be determined by generating a random number sequence. Different light-emitting units use their respective random numbers as their delay duration in different pulse periods.

[0173] According to the above method, correspondingly, starting from the beginning of each pulse period, after a corresponding random delay, the transmission time of the light-emitting unit within each pulse period is determined.

[0174] The duration of each pulse period is greater than or equal to the sum of the upper limit of the random duration and the flight time. The flight time is the time required for the sensing light to travel back and forth across the ranging range.

[0175] Each pulse period consists of two parts: the random duration of the delay and the flight time. In order to meet the delay duration requirements of each light-emitting unit, the pulse period can be set to a reasonable length, which is greater than or equal to the sum of the upper limit of the random duration of each block in the same group and the flight time that meets the ranging requirements.

[0176] Reference Figure 11 As shown, Figure 11 Only the details of the first pulse period, T1, are shown. Other pulse periods are similar. Multiple pulse periods, such as T1, constitute the detection period for a given luminescent unit.

[0177] In terms of luminescence timing, refer to Figure 11 As shown, within each pulse period, each light-emitting unit is provided with a corresponding charging period (represented by Tchg1~TchgN) and a light pulse (the pulse signal corresponding to Trig1~TrigN) located after the charging period.

[0178] The timing of the emission pulse of each light-emitting unit within each pulse period is delayed by a random duration (represented by grid lines) relative to the end of the charging period.

[0179] This random duration can be determined in a similar way to the aforementioned random duration determination method, such as by generating a random number sequence and then assigning a value to the random duration. For specific implementation methods, please refer to the aforementioned embodiments, which will not be repeated here.

[0180] This invention also provides a lidar, the structure of which is as follows: Figure 13 As shown, it includes a receiving module 200 and the aforementioned transmitting module 100. The receiving module 200 includes multiple sensing partitions, which are configured to receive light signals returned from the area scanned by the light-emitting unit.

[0181] Controller 2 is also used to control the sensing partition to turn on during the detection period of the corresponding light-emitting unit.

[0182] This invention provides an electronic device including the aforementioned lidar.

[0183] Based on the same inventive concept, this invention provides a laser emission method based on a liquid crystal optical phased array, implemented through an emission module comprising multiple emission units, each emission unit including a light-emitting unit, a collimating device, a polarizing device, and an LCOPA unit; the method flow is as follows: Figure 14 As shown, it includes the following steps:

[0184] Step S101: Control the light-emitting units to emit light beams, which are then collimated by a collimating device and adjusted to the same polarization state by a corresponding polarization device before being projected onto the corresponding LCOPA unit. The light-emitting units are positioned on the focal plane of the collimating device, and the LCOPA units in different emitting units are arranged along the first direction;

[0185] Step S102: The controlled LCOPA unit deflects the beam at multiple consecutive angles in the second direction to scan a scanning zone within the field of view. Different light-emitting units are configured to scan multiple scanning zones arranged along the first direction, respectively.

[0186] The emitting unit used in the above method is a light-emitting unit in a planar array light source or a linear array light source.

[0187] The LCOPA is configured to include a deflection angle adjustment period and a light emission ranging period. Each light-emitting unit emits light during the light emission ranging period, and the LCOPA deflects the beam during this period. During the deflection angle adjustment period, the deflection angle of the LCOPA unit on the beam is changed by altering the voltage applied to the electrodes on both sides of the LCOPA. The detection period of each light-emitting unit corresponds to the laser ranging period of the corresponding LCOPA unit.

[0188] Optionally, each liquid crystal optical phased array unit corresponding to a light-emitting unit in the same light-emitting group has the same light-emitting ranging period and the same deflection angle adjustment period.

[0189] Optionally, each liquid crystal optical phased array unit corresponding to the light-emitting unit of different light-emitting groups has a different light-emitting ranging period and a different deflection angle adjustment period.

[0190] In step S102 above, the controlled LCOPA unit deflects the beam at multiple consecutive angles in the second direction to scan a scanning zone within the field of view, including:

[0191] By applying different voltages to different discrete electrodes, the liquid crystal molecules in the liquid crystal regions corresponding to the different discrete electrodes rotate at different angles, so that different liquid crystal regions achieve different deflection angles to the unit beam. By modulating the deflection angles of multiple unit beams in the beam, the deflection angle of the entire beam in the LCOPA unit is controlled, so that the beam achieves multiple consecutive angle deflections in the second direction to scan a scanning zone in the field of view.

[0192] Figure 7 Taking an 8-group zonal emission system as an example, each group corresponds to a portion of the radar's field of view. For instance, one group of zonal emission corresponds to a line in the vertical direction of the lidar, while horizontal scanning is achieved by deflecting the lidar at different angles using the LCOPA. Since each zonal emission can independently control its deflection angle, at any given moment, the fields of view illuminated by different zonal emission systems can be spatially separate. Figure 7 As shown in the medium gray blocks, the scan positions can also be continuous. Preferably, the scan positions of the partitioned emission should be separated as much as possible to reduce high back-dilation.

[0193] In addition to spatially separating pixels that work simultaneously, the detection time of each pixel can also be designed to reduce high inverse dilatation. Figure 8 The operating timing of an optional embodiment is illustrated, taking four-group zonal emission as an example. Since liquid crystal flip-modulation requires response time, the operation of the lidar can be divided into a liquid crystal deflection modulation period and a emission ranging period. Figure 8The LCOPA units in the central zone simultaneously flip to change the light deflection angle, followed by multiple laser pulses emitted during the ranging period. The corresponding pixels receive the echo signals to calculate the target distance. Although the ranging periods of the zone-based emission overlap, the emission of multiple pulses from different zones is pseudo-random, which can eliminate high back dilation to some extent.

[0194] Furthermore, since the liquid crystal flip-modulation of each zone occupies most of the time, while the emission and ranging period is relatively short, the timing can be controlled to allow different zones to emit lasers at staggered times to illuminate the field of view. That is, while some zones are performing liquid crystal modulation, other zones are emitting lasers to illuminate the field of view for ranging, as described above. Figure 9 Another alternative embodiment is that the pixels of different partitions are not only spatially separated but also temporally separated, which can further reduce the occurrence of optical crosstalk and reduce interference problems such as high inversion dilation.

[0195] Optionally, controlling the light-emitting units to emit light beams includes: controlling the light-emitting units in each of the light-emitting units to emit light pulses in a preset order during corresponding detection time periods, with each light-emitting unit corresponding to a different detection time period, and the different detection time periods being set sequentially, wherein, within the detection time period corresponding to the same light-emitting group, at least two light-emitting units in the light-emitting unit emit light pulses at different times.

[0196] Optionally, controlling the light-emitting units in each of the light-emitting units to emit light pulses in a preset order during their respective detection time periods includes:

[0197] Multiple light-emitting units in the same light-emitting group are controlled to emit multiple rounds of light pulses according to a preset time sequence during the corresponding detection period. A detection period includes multiple pulse periods corresponding to the multiple rounds of light pulse emission. Multiple light-emitting units emit one light pulse in one pulse period to complete one round of light pulse emission. At least two light-emitting units emit light pulses at different times in one pulse period.

[0198] Optionally, the time when the same light-emitting unit emits light pulses in multiple pulse periods within a detection period has a corresponding time delay relative to the reference time of each pulse period, and the length of the time delay corresponding to each pulse period varies randomly.

[0199] Optionally, the pulse period includes a light emission adjustment interval with a preset duration, and the times when multiple light emission units of the same light emission group emit light pulses within a pulse period are randomly set within the light emission adjustment interval of the pulse period.

[0200] Optionally, the timing of the emitted light pulses by multiple light-emitting units in the same light-emitting group within the corresponding detection period can be determined in the following manner:

[0201] A set of random number sequences is generated for a pulse period within the corresponding detection period. The random number sequence includes multiple random numbers that correspond one-to-one with multiple light-emitting units. These random numbers serve as the random duration of the time when each of the multiple light-emitting units emits a light pulse within the pulse period, relative to the reference time of the pulse period. The value of the random duration is greater than or equal to zero and less than or equal to the preset duration of the light emission adjustment interval.

[0202] The timing at which multiple light-emitting units emit light pulses within the pulse period is determined based on the random duration, so as to control the multiple light-emitting units to emit light pulses at randomly set time intervals within the pulse period.

[0203] Optionally, the timing of the emitted light pulses by multiple light-emitting units in the same light-emitting group within the corresponding detection period can be determined in the following manner:

[0204] A set of random number sequences is generated for each light-emitting unit. The random number sequence includes multiple random numbers that correspond one-to-one with multiple pulse periods of the light-emitting unit within the detection period. These random numbers are used as random durations of the time when the light-emitting unit emits a light pulse within the corresponding pulse period, relative to the reference time of the pulse period. The value of the random duration is greater than or equal to zero and less than or equal to the preset duration of the light emission adjustment interval.

[0205] The timing of light emission by the light-emitting unit within the corresponding multiple pulse periods is determined based on the random duration, so as to control multiple light-emitting units in the same light-emitting group to emit light pulses at randomly set time intervals within a pulse period.

[0206] Optionally, controlling at least two light-emitting units in the same light-emitting group to emit light pulses at different times within a pulse period includes:

[0207] Within at least one pulse period, the timing at which each light-emitting unit emits a light pulse is different.

[0208] Optionally, within the detection period corresponding to the same light-emitting group, at least two light-emitting units emit light pulses at times with a time difference within a pulse period, and the time difference formed by the at least two light-emitting units in different pulse periods varies randomly.

[0209] Optionally, within the detection period corresponding to the same light-emitting group, the times at which multiple light-emitting units of the light-emitting group emit light pulses within a pulse period form multiple corresponding time differences, and the time differences formed by the multiple light-emitting units of the light-emitting group in different pulse periods vary randomly.

[0210] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0211] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0212] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A transmitting module based on a liquid crystal optical phased array, characterized in that, It includes a controller, a collimating device, a polarizing device, and multiple emitting units, each of which includes a light-emitting unit and a corresponding liquid crystal optical phased array unit; The collimating device is used to collimate the light beam emitted by the light-emitting unit; The polarization device is used to adjust the polarization state of the light beam emitted by the light-emitting unit before it enters the liquid crystal optical phased array unit. The light-emitting unit is disposed on the focal plane of the collimating device; by selecting light-emitting units at different positions on the focal plane to emit light, a scanning beam emitted in different directions after being deflected by the corresponding liquid crystal optical phased array unit is obtained. The controller is used to control the light-emitting unit to emit light during the corresponding detection period and to control the deflection angle of the light beam by the corresponding liquid crystal optical phased array unit in the same emitting unit, so as to scan the corresponding sub-region in the field of view. The plurality of light-emitting units are divided into several light-emitting groups, each light-emitting group including at least one light-emitting unit, and the controller is configured to control the light-emitting units to emit light in the corresponding detection time period according to the divided light-emitting groups, each light-emitting group corresponding to a different detection time period, and the different detection time periods are set sequentially. Within a detection period corresponding to the same light-emitting group, each light-emitting unit in the same light-emitting group has the same light emission time, and the light deflection angles set by each liquid crystal optical phased array unit belonging to the same emission unit as each light-emitting unit in the same light-emitting group are not exactly the same within the detection period.

2. The transmitting module as described in claim 1, characterized in that, The liquid crystal optical phased array units in the plurality of transmitting units are discretely arranged liquid crystal optical phased array devices; or The liquid crystal optical phased array unit in the plurality of transmitting units is a liquid crystal optical phased array region on an integral liquid crystal optical phased array device that can be independently controlled.

3. The transmitting module as described in claim 1, characterized in that, The light-emitting unit is a light-emitting unit in a planar array light source or a linear array light source.

4. The transmitting module as described in claim 1, characterized in that, The working period of the liquid crystal optical phased array unit includes a deflection angle adjustment period and a light emission ranging period; The controller is configured to control the liquid crystal optical phased array unit to maintain the corresponding light deflection angle unchanged during the light emission ranging period, and to switch the light deflection angle during the deflection angle adjustment period. The emission ranging period of the liquid crystal optical phased array unit at least partially overlaps with the detection period of the emission of the corresponding emission unit in the same emission unit.

5. The transmitting module as described in claim 4, characterized in that, Each liquid crystal optical phased array unit corresponding to a light-emitting unit within the same light-emitting group has the same light-emitting ranging period and the same deflection angle adjustment period; or... Each liquid crystal optical phased array unit corresponding to a light-emitting unit of a different light-emitting group has a different light-emitting ranging period and a different deflection angle adjustment period.

6. The transmitting module as described in claim 1, characterized in that, Within a detection period corresponding to the same light-emitting group, the light-emitting times of different light-emitting units in the same light-emitting group are not exactly the same.

7. The transmitting module as described in claim 6, characterized in that, The controller is configured to control the light-emitting unit to emit light pulses in multiple rounds according to a preset time sequence within the corresponding detection period. One detection period includes multiple pulse periods corresponding to multiple rounds of light pulse emission. And control multiple light-emitting units in the same light-emitting group to emit a light pulse respectively in a pulse period to complete a round of light pulse emission. The times when different light-emitting units in the same light-emitting group emit light pulses in a pulse period are not exactly the same.

8. The transmitting module as described in claim 7, characterized in that, The controller is configured to control that, within at least one pulse period, the individual light-emitting units in the same light-emitting group emit light pulses at different times.

9. The transmitting module as described in claim 7, characterized in that, The controller is further configured to control the same light-emitting unit to emit light pulses at times during multiple pulse periods within a detection period, with each pulse period having a corresponding time delay relative to a reference time of its respective pulse period, and the length of the time delay corresponding to each pulse period varying randomly.

10. The transmitting module as described in claim 7, characterized in that, The pulse period includes a light emission adjustment interval with a preset duration. The times at which multiple light emission units of the same light emission group emit light pulses within a pulse period are randomly set within the light emission adjustment interval of that pulse period.

11. The transmitting module as described in claim 10, characterized in that, The timing of light pulse emission from multiple light-emitting units in the same light-emitting group during a corresponding detection period is determined using the following method: A set of random number sequences is generated for a pulse period within the corresponding detection period. The random number sequence includes multiple random numbers that correspond one-to-one with multiple light-emitting units. These random numbers serve as the random duration of the delay between the time when each of the multiple light-emitting units emits a light pulse and the reference time of the pulse period. The value of the random duration is greater than or equal to zero and less than or equal to the preset duration of the light emission adjustment interval. The timing at which multiple light-emitting units emit light pulses within the pulse period is determined based on the random duration, so as to control the multiple light-emitting units to emit light pulses at randomly set time intervals within the pulse period.

12. The transmitting module as described in claim 10, characterized in that, The timing of light pulse emission from multiple light-emitting units in the same light-emitting group during a corresponding detection period is determined using the following method: A set of random number sequences is generated for each light-emitting unit. The random number sequence includes multiple random numbers that correspond one-to-one with multiple pulse periods of the light-emitting unit within the detection period. These random numbers are used as random durations of the time when the light-emitting unit emits a light pulse within the corresponding pulse period, relative to the reference time of the pulse period. The value of the random duration is greater than or equal to zero and less than or equal to the preset duration of the light emission adjustment interval. The timing of light emission by the light-emitting unit within the corresponding multiple pulse periods is determined based on the random duration, so as to control multiple light-emitting units in the same light-emitting group to emit light pulses at randomly set time intervals within a pulse period.

13. The transmitting module as described in claim 7, characterized in that, Within the detection period corresponding to the same light-emitting group, at least two light-emitting units emit light pulses at times with a time difference within a pulse period, and the time difference formed by the at least two light-emitting units in different pulse periods varies randomly.

14. The transmitting module as described in claim 7, characterized in that, Within the detection period corresponding to the same light-emitting group, the times at which multiple light-emitting units of the same light-emitting group emit light pulses within a pulse period form multiple time differences with each other, and the time differences formed by the multiple light-emitting units of the same light-emitting group in different pulse periods vary randomly.

15. The transmitting module as described in claim 1, characterized in that, The plurality of light-emitting units are arranged in an array, and the controller is further configured to treat at least a portion of the light-emitting units located in each of the N columns as a light-emitting group. Alternatively, at least a portion of the light-emitting units located in each of the N rows can be considered as a light-emitting group; where N is an integer greater than or equal to 1.

16. The transmitting module as described in claim 1, characterized in that, The array positions of different light-emitting units in the same row or column within the same light-emitting group are not continuous, and are separated from each other by light-emitting units from at least one other light-emitting group.

17. The transmitting module as described in claim 7, characterized in that, The light beams emitted by the same light-emitting unit during different detection periods are deflected by the corresponding liquid crystal optical phased array unit at different light deflection angles to correspond to the same scanning partition within the scanning field of view; wherein, each light deflection angle corresponds to scanning a sub-region within the same scanning partition; The light beams emitted by different light-emitting units are deflected by the corresponding liquid crystal optical phased array units to correspond to different scanning zones within the scanning field of view.

18. The transmitting module as described in claim 17, characterized in that, The liquid crystal optical phased array unit is configured as a one-dimensional deflected beam, and the scanned sub-regions are arranged one-dimensionally along a preset direction within the scanning partition corresponding to the liquid crystal optical phased array; or, The liquid crystal optical phased array unit is configured as a two-dimensional deflection beam, and the scanned sub-region is arranged in two dimensions within the scanning partition corresponding to the liquid crystal optical phased array unit.

19. The transmitting module as described in claim 1, characterized in that, The liquid crystal optical phased array unit is a transmissive liquid crystal optical phased array or a reflective liquid crystal optical phased array.

20. The transmitting module as described in any one of claims 1-19, characterized in that, It also includes a temperature control device for controlling the temperature of the liquid crystal optical phased array unit within the normal operating temperature range; The temperature control device is a device with heating function; or the temperature control device is a device with both heating and cooling functions.

21. A lidar, comprising a receiving module and a transmitting module as described in any one of claims 1-20, wherein the receiving module includes a plurality of sensing partitions disposed corresponding to a plurality of light-emitting units, the sensing partitions being configured to receive light signals returned from a sub-region scanned by a corresponding light-emitting unit; The controller is also used to control the sensing partition to turn on during the detection period of the corresponding light-emitting unit.

22. An electronic device comprising the lidar as described in claim 21.

23. A laser radar scanning method based on a liquid crystal optical phased array, characterized in that, This is achieved through a transmitting module comprising a collimator, a polarizing device, and multiple transmitting units. Each transmitting unit includes a light-emitting unit and a corresponding liquid crystal optical phased array unit. The light-emitting unit is disposed on the focal plane of the collimator. The method includes: According to a preset sequence, light-emitting units at different positions on the focal plane emit light beams during corresponding detection periods. The light beams are collimated by a collimating device and their polarization states are adjusted by a corresponding polarizing device before being projected onto the corresponding liquid crystal optical phased array unit. The multiple light-emitting units are divided into several light-emitting groups, each light-emitting group including at least one light-emitting unit. The controller is configured to control the light-emitting units to emit light according to the divided light-emitting groups during corresponding detection periods. Each light-emitting group corresponds to a different detection period, and the different detection periods are set sequentially. Within a detection period corresponding to the same light-emitting group, each light-emitting unit in the same light-emitting group has the same light-emitting time, and the light deflection angles set by each liquid crystal optical phased array unit belonging to the same emission unit as each light-emitting unit in the same light-emitting group are not exactly the same within the detection period. The deflection angle of the beam is controlled by the corresponding liquid crystal optical phased array unit to scan the corresponding sub-region in the field of view.

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