Light detection system, light detection method, and lidar system

Abstract

The application provides an optical detection system, an optical detection method and a laser radar system, which can be applied to the fields of optical communication, laser radar, laser radar positioning, laser radar ranging, image processing and the like. The system comprises a beam splitting surface, a first light beam reflecting surface, a second light beam reflecting surface, two detector arrays and a readout circuit. The first light beam reflecting surface and the second light beam reflecting surface are respectively used for reflecting two mixed light beams after the mixed light beams of the echo light and the local oscillator light pass through the beam splitting surface; the two detector arrays are respectively used for converting the two mixed light beams into electrical signals; and the readout circuit is used for processing the electrical signals output by the two detector arrays, wherein the spacing between the detector arrays, the spacing between the light beam reflecting surfaces and the beam splitting surface and the spacing between the parallel light beam reflecting surfaces are related. The detection is realized by using two coherent signals, and the detection sensitivity of the echo light signal can be improved and the detection distance can be increased without relying on the size of the echo light energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optics, in particular to an optical detection system, an optical detection method and a laser radar system. BACKGROUND

[0002] As an active sensor, the laser radar is an indispensable key part in the fields of automatic driving, robots, unmanned aerial vehicles and the like. The laser radar is generally composed of a laser, a transmitting optical module, a receiving optical module, a detector and a signal processing module. The laser emits a light pulse with a fixed period, which is reflected by a target object and then received by the detector. The flight time of the light pulse is calculated, and the distance of the target object is solved.

[0003] In the prior art, the detector array directly detects the intensity of the received light signal and outputs an electrical signal. A significant disadvantage of direct intensity detection is its low detection sensitivity. In particular, in the application of Flash laser radar, since the laser beam is a divergent surface light beam irradiated onto the target object, the light echo energy received by each pixel in the detector array will be very low. If direct intensity detection is used, the ranging range of the Flash laser radar will be very limited. SUMMARY

[0004] The present application provides an optical detection system, an optical detection method and a laser radar system, so as to improve the detection sensitivity and increase the detection range.

[0005] In a first aspect, an optical detection system is provided, which comprises: a beam splitting surface, a first light beam reflecting surface, a second light beam reflecting surface, a first detector array, a second detector array and a readout circuit; the beam splitting surface is used for combining the received echo light and the local oscillator light to obtain a first mixed light beam and a second mixed light beam; the first light beam reflecting surface is used for reflecting the first mixed light beam so that the first mixed light beam is input to the first detector array; the second light beam reflecting surface is used for reflecting the second mixed light beam so that the second mixed light beam is input to the second detector array; the first detector array is used for converting the first mixed light beam into a first electrical signal; the second detector array is used for converting the second mixed light beam into a second electrical signal; the readout circuit is used for processing the first electrical signal output by the first detector array and the second electrical signal output by the second detector array, and outputting the processed result; wherein the spacing between the first detector array and the second detector array corresponds to the spacing between the beam splitting surface and the first light beam reflecting surface parallel thereto, and the spacing between the two second light beam reflecting surfaces parallel to each other.

[0006] Based on the above technical solution, after the echo light and the local light are optically combined and mixed, a plurality of mixed light beams (such as a first mixed light beam and a second mixed light beam) are obtained, and the plurality of mixed light beams are input into a plurality of detector arrays, such as the first mixed light beam being input into a first detector array and the second mixed light beam being input into a second detector array. Each detector array performs photoelectric conversion, and the converted electrical signals are input into a readout circuit. The readout circuit performs a series of processes on the input electrical signals, thereby realizing heterodyne coherent detection. Using the two coherent signals to realize detection can not completely rely on the size of the optical echo energy, and can improve the detection sensitivity of the echo light signal and increase the detection distance.

[0007] In addition, the mixed light after the optical combination and mixing is reflected by the light beam reflection surface and input into the detector array. Specifically, after the mixed light is reflected by the light beam reflection surface, it is incident into the detector array through the light beam exit end surface. Therefore, the spacing between the light beam exit end surfaces can be flexibly adjusted by adjusting the position of the light beam reflection surface, so that the optical axis spacing of the plurality of parallel light beams output by the plurality of light beam exit end surfaces can be flexibly adjusted. In addition, the design, processing and installation of the light beam reflection surface are flexible and convenient.

[0008] In addition, the spacing between the detector arrays corresponds to the spacing between the beam splitting surface and the first light beam reflection surface parallel thereto, and the spacing between the two second light beam reflection surfaces parallel thereto. That is, the position of the light beam reflection surface is related to the spacing between the detector arrays. Alternatively, it can also be understood that based on the position of the light beam reflection surface (such as the spacing between the light beam reflection surface and the beam splitting surface, the spacing between the light beam reflection surfaces), the spacing between the detector arrays is determined so that the mixed light beam can be input into the detector array; or, based on the spacing between the detector arrays, the position of the light beam reflection surface (such as the spacing between the light beam reflection surface and the beam splitting surface, the spacing between the light beam reflection surfaces) is determined so that the mixed light beam can be input into the detector array through the reflection of the light beam reflection surface. Therefore, by adjusting the position of the light beam reflection surface, the spacing between the detector arrays can be adjusted, or based on the known spacing between the detector arrays, the position of the light beam reflection surface can be adjusted, which has stronger applicability.

[0009] In combination with the first aspect, in some implementations of the first aspect, the propagation direction of the first mixed light beam is parallel to the propagation direction of the second mixed light beam.

[0010] Based on the above technical solution, the light beams input into the two detector arrays through the light beam reflection surface are parallel, which is easy for optical processing and back-end chip manufacturing.

[0011] With reference to the first aspect, in some implementations of the first aspect, a propagation direction of the first mixed light beam is perpendicular to a light-sensitive surface of the first detector array, and a propagation direction of the second mixed light beam is perpendicular to a light-sensitive surface of the second detector array.

[0012] With reference to the first aspect, in some implementations of the first aspect, the beam splitting surface is configured to reflect and transmit the received echo light and the received local light; the first mixed light beam is a light beam after the reflected echo light and the transmitted local light are combined, and the second mixed light beam is a light beam after the transmitted echo light and the reflected local light are combined.

[0013] Based on the above technical solution, the echo light and the local light can be combined and mixed by the beam splitting surface.

[0014] With reference to the first aspect, in some implementations of the first aspect, a difference between an optical path of the first mixed light beam from the beam splitting surface to the first detector array and an optical path of the second mixed light beam from the beam splitting surface to the second detector array is related to a heterodyne period and a speed of light.

[0015] With reference to the first aspect, in some implementations of the first aspect, a difference between an optical path of the first mixed light beam from the beam splitting surface to the first detector array and an optical path of the second mixed light beam from the beam splitting surface to the second detector array is less than (heterodyne period * speed of light / f), where f is a constant.

[0016] For example, f can be 25. That is, the difference between the optical path of the first mixed light beam from the beam splitting surface to the first detector array and the optical path of the second mixed light beam from the beam splitting surface to the second detector array is less than (heterodyne period * speed of light / 25).

[0017] With reference to the first aspect, in some implementations of the first aspect, a difference between an optical path of the first mixed light beam from the beam splitting surface to the first detector array and an optical path of the second mixed light beam from the beam splitting surface to the second detector array is less than or equal to 1 centimeter.

[0018] For example, the optical path between the beam splitting surface and the first detector array of the first mixed light beam is the same as the optical path between the beam splitting surface and the second detector array of the second mixed light beam.

[0019] Based on the above technical solution, by making the optical path between the multi-path mixed light beams and the respective input detector arrays of the beam splitting surface satisfy certain conditions, the design is flexible, and subsequent processing can be ensured.

[0020] With reference to the first aspect, in some implementations of the first aspect, the light detection system can include one or more of the first beam reflection surfaces; and / or, the light detection system can include one or more of the second beam reflection surfaces.

[0021] With reference to the first aspect, in some implementations of the first aspect, any two of the first beam reflection surfaces are parallel or perpendicular to each other; and / or, any two of the second beam reflection surfaces are parallel or perpendicular to each other.

[0022] With reference to the first aspect, in some implementations of the first aspect, a spacing between the first detector array and the second detector array corresponds to a spacing between the first beam reflection surface and the beam splitting surface, and a spacing between two parallel second beam reflection surfaces, including:

[0023] The spacing between the first detector array and the second detector array, the spacing between the first beam reflection surface and the beam splitting surface, and the spacing between two parallel second beam reflection surfaces satisfy the following relationship:

[0024] H0+H6-M<L<H0+H6+M, or, (H0-H3)+(H6-H9)-M<L<(H0-H3)+(H6-H9)+M;

[0025] wherein L represents a center distance between the first detector array and the second detector array; H0 represents a spacing between the beam splitting surface and the first beam reflection surface parallel to the beam splitting surface; H6 represents a longest spacing between two parallel second beam reflection surfaces; H3 represents a shortest spacing between two parallel first beam reflection surfaces; H9 represents a shortest spacing between two parallel second beam reflection surfaces; and M represents a cross-sectional spot size of the first mixed beam and the second mixed beam.

[0026] For example, L=H0+H6.

[0027] For example, L=(H0-H3)+(H6-H9).

[0028] For example, H0=H6. In this case, L=2·H0.

[0029] For example, H0=H6, and H3=H9. In this case, L=2·(H0-H3).

[0030] In some implementations of the first aspect, a distance between any two of the first beam reflection surfaces is greater than or equal to a cross-sectional spot size of the first mixed light beam, and a distance between any two of the second beam reflection surfaces is greater than or equal to a cross-sectional spot size of the second mixed light beam.

[0031] Based on the above technical solution, the spot sizes of the mixed light beams can cover all pixels of the detector arrays.

[0032] In some implementations of the first aspect, the first mixed light beam is input to a same plane as a plane in which the second mixed light beam is input to the second detector array.

[0033] Based on the above technical solution, the multiple mixed light beams are incident on the respective corresponding detector arrays through the same plane, which facilitates the manufacturing of the detector array chips and the readout circuit chips (wafers for manufacturing the chips and printed circuit boards (PCBs) for connecting the chips are both in a plane), facilitates integration, and reduces engineering installation complexity.

[0034] In some implementations of the first aspect, a number of single-tube detectors in the first detector array is the same as a number of single-tube detectors in the second detector array.

[0035] Based on the above technical solution, the number of single-tube detectors in each detector array is the same, which can reduce circuit complexity. For example, a single-detector output end on the first detector array and a single-detector output end on the second detector array can be commonly input to a same signal demodulation unit on the readout circuit.

[0036] In some implementations of the first aspect, the first detector array and the second detector array are connected to the readout circuit.

[0037] Based on the above technical solution, the multiple detector arrays (for example, two detector arrays) share one readout circuit. Therefore, the number of readout circuits and circuit complexity can be reduced, and costs can be reduced.

[0038] In some implementations of the first aspect, the readout circuit includes multiple signal demodulation units; each signal demodulation unit is connected to one single-tube detector in the first detector array and one single-tube detector in the second detector array, and each signal demodulation unit is configured to process an electrical signal output by the single-tube detector connected to the signal demodulation unit.

[0039] With reference to the first aspect, in some implementations of the first aspect, the readout circuit includes a plurality of signal demodulation units; each single-tube detector in the first detector array is connected to a first end of a first switch, and each single-tube detector in the second detector array is connected to a first end of a second switch; each signal demodulation unit is connected to second ends of the plurality of first switches in the first detector array and second ends of the plurality of second switches in the second detector array; and the second ends of the plurality of first switches are connected in parallel, and the second ends of the plurality of second switches are connected in parallel.

[0040] According to the above technical solution, at each moment, only the switches of a certain column or a certain row can be turned off, so that the signals output by the detectors connected to the turned-off switches of the column or the row are input to the signal demodulation units.

[0041] In a second aspect, a light detection method is provided, which is applied to a light detection system including a beam splitting surface, a first light beam reflecting surface, a second light beam reflecting surface, a first detector array, a second detector array, and a readout circuit. The light detection method includes: combining received echo light and local oscillator light to obtain a first mixed light beam and a second mixed light beam; reflecting the first mixed light beam by the first light beam reflecting surface and inputting the first mixed light beam to the first detector array; reflecting the second mixed light beam by the second light beam reflecting surface and inputting the second mixed light beam to the second detector array; converting the first mixed light beam into a first electrical signal by the first detector array; converting the second mixed light beam into a second electrical signal by the second detector array; processing the first electrical signal output by the first detector array and the second electrical signal output by the second detector array by the readout circuit, and outputting a processed result; and the spacing between the first detector array and the second detector array corresponds to the spacing between the beam splitting surface and the first light beam reflecting surface parallel to the beam splitting surface, and the spacing between the two second light beam reflecting surfaces parallel to each other.

[0042] With reference to the second aspect, in some implementations of the second aspect, the propagation direction of the first mixed light beam is parallel to the propagation direction of the second mixed light beam.

[0043] With reference to the second aspect, in some implementations of the second aspect, the propagation direction of the first mixed light beam is perpendicular to the light-sensitive surface of the first detector array, and the propagation direction of the second mixed light beam is perpendicular to the light-sensitive surface of the second detector array.

[0044] With reference to the second aspect, in some implementations of the second aspect, the beam splitting surface reflects and transmits the received echo light, and reflects and transmits the received local light; the first mixed light beam is a light beam after the reflected echo light and the transmitted local light are combined, and the second mixed light beam is a light beam after the transmitted echo light and the reflected local light are combined.

[0045] With reference to the second aspect, in some implementations of the second aspect, a difference between an optical path of the first mixed light beam from the beam splitting surface to the first detector array and an optical path of the second mixed light beam from the beam splitting surface to the second detector array is related to a heterodyne period and a speed of light.

[0046] With reference to the second aspect, in some implementations of the second aspect, a difference between an optical path of the first mixed light beam from the beam splitting surface to the first detector array and an optical path of the second mixed light beam from the beam splitting surface to the second detector array is less than (heterodyne period * speed of light / f), where f is a constant.

[0047] With reference to the second aspect, in some implementations of the second aspect, a difference between an optical path of the first mixed light beam from the beam splitting surface to the first detector array and an optical path of the second mixed light beam from the beam splitting surface to the second detector array is less than or equal to 1 centimeter.

[0048] For example, an optical path between the first mixed light beam and the first detector array is the same as an optical path between the second mixed light beam and the second detector array.

[0049] With reference to the second aspect, in some implementations of the second aspect, any two of the first light beam reflecting surfaces are parallel to each other or perpendicular to each other; and / or, any two of the second light beam reflecting surfaces are parallel to each other or perpendicular to each other.

[0050] With reference to the second aspect, in some implementations of the second aspect, a distance between the first detector array and the second detector array corresponds to a distance between the first light beam reflecting surface and the beam splitting surface, and a distance between two parallel second light beam reflecting surfaces, including:

[0051] The distance between the first detector array and the second detector array, the distance between the first light beam reflecting surface and the beam splitting surface, and the distance between the two parallel second light beam reflecting surfaces satisfy the following relationship:

[0052] H0+H6-M < L < H0+H6+M, or, (H0-H3)+(H6-H9)-M < L < (H0-H3)+(H6-H9)+M;

[0053] wherein L represents a center distance between the first detector array and the second detector array; H0 represents a distance between the beam splitting surface and the first beam reflecting surface parallel to the beam splitting surface; H6 represents a longest distance between two second beam reflecting surfaces parallel to each other; H3 represents a shortest distance between two first beam reflecting surfaces parallel to each other; H9 represents a shortest distance between two second beam reflecting surfaces parallel to each other; and M represents a cross-sectional spot size of the first mixed beam and the second mixed beam.

[0054] For example, L = H0+H6.

[0055] For example, L = (H0-H3)+(H6-H9).

[0056] For example, H0 = H6. In this case, L = 2·H0.

[0057] For example, H0 = H6, and H3 = H9. In this case, L = 2·(H0-H3).

[0058] With reference to the second aspect, in some implementations of the second aspect, a distance between any two first beam reflecting surfaces is greater than or equal to the cross-sectional spot size of the first mixed beam, and a distance between any two second beam reflecting surfaces is greater than or equal to the cross-sectional spot size of the second mixed beam.

[0059] With reference to the second aspect, in some implementations of the second aspect, a plane in which the first mixed beam enters the plane in which the first detector array is located, and a plane in which the second mixed beam enters the plane in which the second detector array is located are the same plane.

[0060] With reference to the second aspect, in some implementations of the second aspect, a number of single-tube detectors in the first detector array is the same as a number of single-tube detectors in the second detector array.

[0061] With reference to the second aspect, in some implementations of the second aspect, the first detector array and the second detector array are both connected to the readout circuit.

[0062] With reference to the second aspect, in some implementations of the second aspect, the readout circuit includes a plurality of signal demodulation units; each signal demodulation unit is connected to one single-tube detector in the first detector array and one single-tube detector in the second detector array, and each signal demodulation unit processes an electrical signal output by the single-tube detector connected to the signal demodulation unit.

[0063] With reference to the second aspect, in some implementations of the second aspect, the readout circuit includes a plurality of signal demodulation units; each single-tube detector in the first detector array is connected to a first end of a first switch, and each single-tube detector in the second detector array is connected to a first end of a second switch; each signal demodulation unit is connected to second ends of the plurality of first switches in the first detector array and second ends of the plurality of second switches in the second detector array; and the second ends of the plurality of first switches are connected in parallel, and the second ends of the plurality of second switches are connected in parallel.

[0064] In a third aspect, a laser radar system is provided, which includes a transmitting module and a receiving module. The transmitting module is configured to transmit a light beam. The receiving module is configured to receive the light beam and perform the light detection method according to the second aspect.

[0065] For example, the transmitting module is configured to transmit a light beam to obtain a return light and a local light. The receiving module includes a beam splitting module, a first light beam reflecting module, a second light beam reflecting module, a first conversion module, a second conversion module, and a processing module. The beam splitting module is configured to combine the received return light and local light to obtain a first mixed light beam and a second mixed light beam. The first reflecting module is configured to reflect the first mixed light beam so that the first mixed light beam is input to the first conversion module. The second reflecting module is configured to reflect the second mixed light beam so that the second mixed light beam is input to the second conversion module. The first conversion module is configured to convert the first mixed light beam into a first electrical signal. The second conversion module is configured to convert the second mixed light beam into a second electrical signal. The processing module is configured to process the first electrical signal and the second electrical signal. The distance between the first conversion module and the second conversion module corresponds to the distance between the beam splitting module and the first light beam reflecting module parallel to the beam splitting module, and the distance between the two second light beam reflecting modules.

[0066] For example, the light beam module is configured to perform the steps performed by the beam splitting surface in the light detection system according to the first aspect.

[0067] For example, the first conversion module is configured to perform the steps performed by the first detector array in the light detection system according to the first aspect.

[0068] For example, the second conversion module is configured to perform the steps performed by the second detector array in the light detection system according to the first aspect.

[0069] The processing module is configured to perform the steps performed by the readout circuit in the light detection system according to the first aspect.

[0070] In a fourth aspect, a computer readable storage medium is provided, which stores a computer program. When the computer program is executed by an apparatus, the apparatus is caused to perform the processing steps in the first aspect to the third aspect, such as photoelectric conversion, processing of signals, etc.

[0071] In a fifth aspect, a computer program product is provided, which contains instructions. When the instructions are executed by a computer, the apparatus is caused to perform the processing steps in the first aspect to the third aspect, such as photoelectric conversion, processing of signals, etc. BRIEF DESCRIPTION OF DRAWINGS

[0072] Figure 1 A schematic block diagram of a lidar system is shown.

[0073] Figure 2 A schematic block diagram of a lidar system according to an embodiment of the present application is shown.

[0074] Figure 3 A schematic block diagram of an area array balanced receiver according to an embodiment of the present application is shown.

[0075] Figure 4 A schematic block diagram of an area array balanced receiver according to an embodiment of the present application is shown.

[0076] Figure 5 A schematic block diagram of an area array balanced receiver according to another embodiment of the present application is shown.

[0077] Figure 6 A schematic block diagram of an area array balanced receiver according to another embodiment of the present application is shown.

[0078] Figure 7 A schematic block diagram of an optical analog front end according to an embodiment of the present application is shown.

[0079] Figure 8 A schematic block diagram of an optical analog front end according to another embodiment of the present application is shown.

[0080] Figure 9 A schematic block diagram of an optical analog front end according to another embodiment of the present application is shown.

[0081] Figure 10 A schematic diagram of connection of two detector arrays and a ROIC according to an embodiment of the present application is shown.

[0082] Figure 11A schematic diagram showing the connection between two detector arrays and ROIC according to another embodiment of this application is shown.

[0083] Figure 12 A schematic diagram of two detector arrays and an optical simulation front end according to another embodiment of this application is shown.

[0084] Figure 13 A schematic structural diagram of a single signal demodulation unit in a ROIC provided according to an embodiment of this application is shown.

[0085] Figure 14 A schematic diagram of an iTOF lidar based on heterodyne coherent detection provided according to an embodiment of this application is shown.

[0086] Figure 15 A schematic block diagram of a lidar system applicable to embodiments of this application is shown.

[0087] Figure 16 A schematic block diagram of a photodetector method provided according to an embodiment of this application is shown. Detailed Implementation

[0088] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0089] LiDAR (light detection and ranging), as an active sensor, is an indispensable key component in fields such as autonomous driving, robotics, and drones. For example... Figure 1 As shown, a lidar system generally consists of a laser, a transmitting optical module, a receiving optical module, a detector, and a signal processing module. The laser emits light pulses with a fixed period. After being reflected by the target object and received by the detector, the flight time of the light pulse is calculated to determine the distance to the target object. Simply put, lidar can be used as a ranging system. Its working principle is roughly as follows: a light source (usually a laser) emits a beam of light (i.e., laser) towards the target object. The target object reflects this light, and the detector receives the reflected light. A timer (such as a system clock) calculates the time difference between the light reflection and reception. Based on this time difference and the speed of light, the target distance can be calculated.

[0090] The laser radar performs 3D ranging imaging on a target object through a light beam scanning mechanism. Currently, common scanning methods include: light beam scanning through a mechanical motor, light beam scanning through a micro-mirror, or light beam scanning through a micro-electro-mechanical system (MEMS) micro-mirror. The light beam scanning methods in the various laser radars shown above all have rotating or vibrating components, and it is still difficult to achieve miniaturization, vehicle-grade anti-vibration performance, and service life requirements.

[0091] In addition, there is also a solution of using a Flash laser radar system for ranging. The solution includes a laser, a light beam expansion element, a receiving lens, and a detector array. The light beam emitted by the laser forms a surface light beam after passing through the optical expansion element, the surface light beam is reflected after irradiating the target object and is received by the receiving optical lens group into the detector array. The detector array directly detects the intensity of the received light signal and outputs an electrical signal, and forms a 3D point cloud image after rear-end data processing. The existing Flash laser radar system uses floodlight irradiation and a 2D detector array for receiving, without any moving parts, and has high reliability.

[0092] However, in the prior art, the light echo signal is mainly converted into an electrical signal based on direct intensity detection. A significant disadvantage of direct intensity detection is its low detection sensitivity. Especially in Flash laser radar applications, since the laser beam is a divergent surface light beam irradiating the target object, the light echo energy (power) received by each pixel in the detector array will be very low. If direct intensity detection is used, it will result in a very limited ranging range of the Flash laser radar.

[0093] Therefore, the embodiments of the present application provide a solution that can improve detection sensitivity and increase the ranging range. The solution provided by the embodiments of the present application can be applied to the fields of optical communication, light beam scanning, laser radar, laser radar positioning, laser radar ranging, image processing, etc.

[0094] The various embodiments provided by the present application will be described in detail below with reference to the accompanying drawings.

[0095] Figure 2 A schematic block diagram of a laser radar system according to an embodiment of the present application is shown.

[0096] As shown in Figure 2 , the light beam emitted by the laser is expanded into a surface light beam after passing through the transmitting lens, and the surface light beam irradiates the target object. The target object reflects the surface light beam, and the reflected echo light is received by the receiving lens and irradiates the surface array balanced receiver together with the frequency-shifted local oscillator light emitted by the laser. Through a series of processes of the surface array balanced receiver, the 3D image of the target object is output.

[0097] It should be understood that the area array balanced receiver is only one possible naming, for example, it can also be called an optical detection system, and the naming does not limit the protection scope of the embodiments of the present application, and the naming capable of achieving the same function is applicable to the embodiments of the present application. In the following, the area array balanced receiver is mainly taken as an example for description.

[0098] Figure 3 A schematic block diagram of an area array balanced receiver provided by an embodiment of the present application is shown.

[0099] As shown in Figure 3 , the area array balanced receiver includes but is not limited to an optical analog front end (OAFE), two sensor arrays and a read out integrated circuit (ROIC).

[0100] The optical analog front end can be used for optical beam combining and mixing (or optical mixing) of the echo light and the local oscillator light. For example, the optical analog front end includes a beam splitting surface (or a beam splitting surface of a light beam), which is used for beam combining of the received echo light and the local oscillator light to obtain two mixed light beams, such as a first mixed light beam and a second mixed light beam. The optical analog front end can also include one or more first light beam reflecting surfaces and one or more second light beam reflecting surfaces. The first light beam reflecting surface is used for reflecting the first mixed light beam so that the first mixed light beam is input to the first sensor array; the second light beam reflecting surface is used for reflecting the second mixed light beam so that the second mixed light beam is input to the second sensor array.

[0101] The two sensor arrays, such as the first sensor array and the second sensor array, can each complete photoelectric conversion, in other words, the photoelectric conversion of the optical signal is independently completed in each pixel of the two sensor arrays. The ROIC performs a series of processing on the electrical signal output by the sensor array, and finally outputs a 3D image of the target object. It can be understood that the local oscillator light and the echo light are obtained after a series of processing of the laser emitted by the laser. For example, the laser emitted by the laser is divided into two lasers by a beam splitter, one of which is used as the local oscillator light after a frequency shifter; the other laser is used as the emitted light to irradiate the target object, and is used as the echo light after being reflected by the target object. The local oscillator light and the echo light can refer to the existing description, which is not limited.

[0102] Based on the embodiments of the present application, a laser radar based on heterodyne coherent detection is provided. Specifically, the return light and the local light can be optically combined and mixed after mixing, and then input into a plurality of detector arrays. Each detector array respectively performs photoelectric conversion, and inputs the converted electrical signal to an ROIC. The ROIC performs a series of processing on the input electrical signal, thereby realizing heterodyne coherent detection (or also referred to as optical heterodyne detection). Through the embodiments of the present application, the return light and the local light are used for detection, which does not need to completely rely on the size of the optical return energy (power), and can improve the detection sensitivity of the return light signal and increase the detection distance.

[0103] It should be understood that Figure 3 The surface array balanced receiver shown is only illustrative, and is not limited thereto. For example, the surface array balanced receiver can also include other modules. For example, the surface array balanced receiver can also include a mirror group. The mirror group, which can also be referred to as a beam shaping mirror group, can include but is not limited to: an optical lens, a microlens array. Through the mirror group, the local light can be shaped into a parallel light beam, such as a line beam or a surface beam; and the return light can also be shaped into a parallel light beam, such as a line beam or a surface beam.

[0104] It should also be understood that the number of detector arrays can be greater than or equal to 2. For ease of understanding, Figure 2 The two detector arrays are mainly used as an example for illustrative description, and are not limited thereto, for example, a larger number of detector arrays can also be designed, such as 2n detector arrays, n is an integer greater than 1 or equal to 1.

[0105] Figures 4 to 6 Several possible schematic structure diagrams of the surface array balanced receiver are shown.

[0106] The following describes the aspects. The schemes described in the following aspects can be used alone or in combination, and are not limited thereto.

[0107] Aspect 1, optical analog front end.

[0108] Optionally, the optical analog front end includes a beam splitting (BS) surface, or can also be referred to as a splitting surface. The beam splitting surface can split the light incident on the surface, such as partially reflecting and partially transmitting. For example, the beam splitting surface splits the light incident on the surface, 50% reflection, 50% transmission, and the reflected light produces Phase shift.

[0109] Through the beam splitting surface, the return light and the local light can be optically combined and mixed. For ease of description, in the embodiments of the present application, the light after optical combination and mixing is referred to as mixed light.

[0110] In one possible implementation, echo light is incident on a beam splitting surface from one beam incident end surface, and the beam splitting surface transmits a1 % of the echo light and reflects a2 % of the echo light, where a1 and a2 are both greater than 0 and less than 100, and a1 + a2 ≤ 100. Local oscillator light is incident on the beam splitting surface from another beam incident end surface, and the beam splitting surface transmits b2 % of the local oscillator light and reflects b1 % of the local oscillator light, where b1 and b2 are both greater than 0 and less than 100, and b1 + b2 ≤ 100.

[0111] It should be noted that, in actual communication, the optical signal can be lost, and thus a1 + a2 ≤ 100 and b1 + b2 ≤ 100. For example, in some cases, a1 + a2 = 100 and b1 + b2 = 100 in the case of no loss.

[0112] The number of beam splitting surfaces is not limited. In one example, the optical analog front end can include one beam splitting surface, which outputs two mixed lights after optically combining and mixing the echo light and the local oscillator light, for example, one mixed light from each side of the beam splitting surface. The scheme of this example is simple and easy to implement, and has a relatively low cost. It should be understood that the optical analog front end can also include multiple beam splitting surfaces, each of which outputs two mixed lights after optically combining and mixing the echo light and the local oscillator light. Hereinafter, one beam splitting surface is mainly exemplarily described.

[0113] Optionally, the optical analog front end includes a beam reflecting surface. The mixed light after the optical combining and mixing is reflected by the beam reflecting surface and input to the detector array.

[0114] The number of beam reflecting surfaces is not limited. In one example, the optical analog front end can include two beam reflecting surfaces. Each beam reflecting surface corresponds to one detector array, that is, the mixed light input to the detector array is reflected by one beam reflecting surface and then input to the corresponding detector array. In another example, the optical analog front end can include more than two beam reflecting surfaces. One or more beam reflecting surfaces correspond to one detector array, that is, the mixed light input to the detector array is reflected by one or more beam reflecting surfaces and then input to the corresponding detector array.

[0115] In the embodiments of the present application, the optical axis interval of the multiple light beams input to the detector array can be adjusted by adjusting the position of the beam reflecting surface. Specifically, the mixed light is reflected by the beam reflecting surface and then input to the detector array through the beam exit end surface. Therefore, the interval between the beam exit end surfaces can be flexibly adjusted by adjusting the position of the beam reflecting surface, so that the optical axis interval of the multiple parallel light beams output by the multiple beam exit end surfaces can be flexibly adjusted.

[0116] The positions of the beam-splitting surface and the beam-reflecting surface, and the positions of the beam-reflecting surface and the beam-reflecting surface can be flexibly designed according to actual needs.

[0117] In an example, the positions of the beam-splitting surface and the beam-reflecting surface can be parallel, or can be perpendicular, or can be that the beam-splitting surface is perpendicular to part of the beam-reflecting surface and parallel to part of the beam-reflecting surface.

[0118] In another example, the positions of the beam-reflecting surface and the beam-reflecting surface can be parallel, or can be perpendicular, or can be that one beam-reflecting surface is perpendicular to part of the beam-reflecting surface and parallel to part of the beam-reflecting surface.

[0119] In another example, when the beam-splitting surface is parallel to the plurality of beam-reflecting surfaces, the distance between the beam-splitting surface and each beam-reflecting surface can be the same or different.

[0120] In another example, when the plurality of beam-reflecting surfaces are parallel, the distance between any two adjacent beam-reflecting surfaces can be the same or different.

[0121] In another example, when the beam-splitting surface is parallel to the beam-reflecting surface, and the beam-reflecting surface is parallel to the beam-reflecting surface, the distance between the beam-splitting surface and the beam-reflecting surface, and the distance between the beam-reflecting surface and the beam-reflecting surface, can be the same or different.

[0122] Figures 7 to 9 Several possible structures of the optical simulation front end are exemplarily listed.

[0123] A possible structure is shown in Figure 7 .

[0124] In the optical simulation front end shown in Figure 7 , one beam-splitting surface and three beam-reflecting surfaces can be included. To distinguish, the three beam-reflecting surfaces are respectively denoted as beam-reflecting surface 1 (such as Ref1 in Figure 7 ), beam-reflecting surface 2 (such as Ref2 in Figure 7 ), and beam-reflecting surface 3 (such as Ref3 in Figure 7 ).

[0125] The positions of the beam-splitting surface and the beam-reflecting surface, and the positions of the beam-reflecting surface and the beam-reflecting surface can be flexibly designed according to actual needs.

[0126] As shown in Figure 7As shown, the beam splitting surface is parallel to the beam reflecting surface 1, the beam splitting surface is perpendicular to the beam reflecting surface 2, and the beam reflecting surface 2 is parallel to the beam reflecting surface 3. For example, the horizontal distance between the beam splitting surface and the beam reflecting surface 1 is H0, and the horizontal distance between the beam reflecting surface 2 and the beam reflecting surface 3 is H6. The specific values of H0 and H6 are not limited, for example, the horizontal distance between the beam splitting surface and the beam reflecting surface 1 and the horizontal distance between the beam reflecting surface 2 and the beam reflecting surface 3 are the same, such as both H0. For example, H0≥H2, H6≥H2, and H1, H2, H6 are all greater than or equal to M. In the embodiments of the present application, M represents the cross-sectional spot size of the parallel light beam.

[0127] Optionally, the optical path of the mixed light from the beam splitting surface to the beam exit end surface can satisfy certain conditions, as long as it does not affect the subsequent processing of the electrical signal.

[0128] For example, the optical path of the mixed light from the beam splitting surface to the beam exit end surface can be the same. For example, the optical path of the mixed light from the beam splitting surface to the beam exit end surface is equal to the length of the beam reflecting surface 2, that is, H2. Figure 7 For example, the vertical distance between the beam exit end surface 1 and the beam entrance end surface 1 is equal to the vertical distance between the beam exit end surface 2 and the beam entrance end surface 1, that is, both are H1+H2. Thus, the optical path from the beam splitting surface to the beam exit end surface 1 can be guaranteed to be equal to the optical path from the beam splitting surface to the beam exit end surface 2.

[0129] For another example, the optical path of the mixed light from the beam splitting surface to the beam exit end surface can also be different.

[0130] For example, the optical path of the mixed light from the beam splitting surface to the beam exit end surface can be designed to satisfy a certain range, such as less than or equal to a preset threshold. The size of the preset threshold is not strictly limited, for example, the preset threshold can be 1 centimeter.

[0131] For another example, the optical path of the mixed light from the beam splitting surface to the beam exit end surface is related to the heterodyne period and the speed of light. For example, the optical path of the mixed light from the beam splitting surface to the beam exit end surface is less than (T*c / f), where T represents the heterodyne period, c represents the speed of light in the atmosphere, and f is a constant. For example, f can be 25.

[0132] It should be understood that the above is only an exemplary description, and in actual application, the optical path of the mixed light from the beam splitting surface to the beam exit end surface can be designed according to the needs.

[0133] Optionally, the plurality of beam exit end surfaces are in the same plane. For example, Figure 7 As shown, the beam exit end surface 1 and the beam exit end surface 2 are in the same plane. Through this design, it is easy to manufacture the detector array chip and the ROIC chip (the wafer for manufacturing the chip and the PCB board for connecting the chip are both a plane), easy to integrate, and reduce the complexity of engineering installation.

[0134] use Figure 7 In the case of the optical analog front end shown, the structure of the area array balanced receiver can be as follows: Figure 4 As shown. Figure 4 As shown, a balanced array receiver may include, but is not limited to: mirror group 1 and mirror group 2, an optical analog front end, two detector arrays (such as detector array 1 and detector array 2), and readout circuitry. From Figure 4 As can be seen, the local oscillator light can be shaped into a parallel beam, such as a line beam or a surface beam, through mirror group 1; the echo light can be shaped into a parallel beam, such as a line beam or a surface beam, through mirror group 2.

[0135] One possible implementation involves the local oscillator beam and the echo beam being processed by mirror group 1 and mirror group 2, and then incident on the optical simulation front end in a parallel beam form (including but not limited to line beams and surface beams; this embodiment mainly uses a surface beam as an example) at mutually perpendicular angles. After optical beam combining and mixing at the beam splitting surface, two mixed beams are output, denoted as S. PD1 and S PD2 S PD1 After being reflected by one beam reflecting surface, it is incident on detector array 1; S PD2 After being reflected by two beam reflecting surfaces, the light enters the detector array 2.

[0136] Another possible structure, such as Figure 8 As shown.

[0137] exist Figure 8 The optical simulation front end shown may include one beam splitter and seven beam reflecting surfaces. For distinction, these seven beam reflecting surfaces are denoted as beam reflecting surface 1 (e.g., ...). Figure 8 Ref1 in the middle), beam reflecting surface 2 (such as Ref1), beam reflecting surface 2 Figure 8 Ref2 in the middle), beam reflecting surface 3 (such as ... Figure 8 Ref3 in the middle), beam reflecting surface 4 (such as ... Figure 8 Ref4 in the middle), beam reflecting surface 5 (such as ... Figure 8 Ref5 in the middle), beam reflecting surface 6 (such as ... Figure 8 Ref6 in the middle), beam reflecting surface 7 (such as Figure 8 (Ref7 in the text).

[0138] The positions of the beam splitting surface and the beam reflecting surface, as well as the positions of the beam reflecting surface and the beam reflecting surface, can be flexibly designed according to actual needs.

[0139] like Figure 8As shown, the beam splitter is parallel to beam reflecting surface 1, and the horizontal distance can be denoted as H0. Beam reflecting surface 1 is perpendicular to beam reflecting surface 2, i.e., the angle between them is 90°. Beam reflecting surface 2 is parallel to beam reflecting surface 3, and the horizontal distance can be denoted as H3. The beam splitter is perpendicular to beam reflecting surface 4, i.e., the angle between them is 90°. Beam reflecting surface 4 is parallel to beam reflecting surface 5, and the horizontal distance can be denoted as H0. Beam reflecting surface 5 is perpendicular to beam reflecting surface 6, i.e., the angle between them is 90°. Beam reflecting surface 6 is parallel to beam reflecting surface 7, and the horizontal distance can be denoted as H3. Figure 8 As shown, among beam reflecting surfaces 4, 5, 6, and 7, the longest distance H6 between two parallel beam reflecting surfaces is the distance between beam reflecting surface 4 and beam reflecting surface 5, and the shortest distance H9 between two parallel beam reflecting surfaces is the distance between beam reflecting surface 6 and beam reflecting surface 7. Wherein, H0≥H2, H6≥H2, H3≤H0-M / 2, H9≤H6-M / 2, and H1, H2, H3, H4, H6, and H9 are all greater than or equal to M.

[0140] For example, the optical path length of the mixed light from the beam splitting surface to the beam exit surface can be the same. Figure 8 For example, the perpendicular distance between the beam exit face 1 and the beam incident face 1 is H2+H1+H4, and the perpendicular distance between the beam exit face 2 and the beam incident face 1 is H1+H2+H4. It should be understood that the optical path length of the mixed light from the beam splitting surface to the beam exit face can also be different, and this is not limited.

[0141] Optionally, the exit faces of multiple beams are on the same plane. For example... Figure 8 As shown, beam exit face 1 and beam exit face 2 are on the same plane.

[0142] use Figure 8 In the case of the optical analog front end shown, the structure of the area array balanced receiver can be as follows: Figure 5 As shown. Figure 5 As shown, a balanced array receiver may include, but is not limited to: mirror group 1 and mirror group 2, an optical analog front end, two detector arrays (such as detector array 1 and detector array 2), and readout circuitry. From Figure 5 As can be seen, the local oscillator light can be shaped into a parallel beam, such as a line beam or a surface beam, through mirror group 1; the echo light can be shaped into a parallel beam, such as a line beam or a surface beam, through mirror group 2.

[0143] One possible implementation involves the local oscillator beam and the echo beam being processed by mirror group 1 and mirror group 2, and then incident on the optical simulation front end as parallel beams at mutually perpendicular angles. After optical beam combining and mixing at the beam splitter, two mixed beams are output, denoted as S. PD1 and S PD2 SPD1 After being reflected by three beam reflecting surfaces, the light is incident on detector array 1; S PD2 After being reflected by the four beam reflecting surfaces, the light enters the detector array 2.

[0144] Another possible structure, such as Figure 9 As shown.

[0145] Figure 9 The structure shown is Figure 8 The structures shown are similar, except that in Figure 9 In the structure shown, H3 has been increased. Regarding... Figure 9 The structure can be referenced from... Figure 8 The description of the structure will not be repeated here.

[0146] use Figure 9 In the case of the optical analog front end shown, the structure of the area array balanced receiver can be as follows: Figure 6 As shown. Figure 6 As shown, a balanced array receiver may include, but is not limited to: mirror group 1 and mirror group 2, an optical analog front end, two detector arrays (such as detector array 1 and detector array 2), and readout circuitry. From Figure 6 As can be seen, the local oscillator light can be shaped into a parallel beam, such as a line beam or a surface beam, through mirror group 1; the echo light can be shaped into a parallel beam, such as a line beam or a surface beam, through mirror group 2.

[0147] One possible implementation involves the local oscillator beam and the echo beam being processed by mirror group 1 and mirror group 2, and then incident on the optical simulation front end as parallel beams at mutually perpendicular angles. After optical beam combining and mixing at the beam splitter, two mixed beams are output, denoted as S. PD1 and S PD2 S PD1 After being reflected by three beam reflecting surfaces, the light is incident on detector array 1; S PD2 After being reflected by the four beam reflecting surfaces, the light enters the detector array 2.

[0148] In this embodiment, the position of the beam reflecting surface is related to the spacing between the detector arrays. For example, compared to Figure 8 ,exist Figure 9 In the structure shown, H3 and H6 are increased. Increasing H3 and H6 reduces the horizontal distance between the beam exit face 1 and the beam exit face 2, thereby reducing the distance between the optical axes of the emitted parallel beams, and ultimately reducing the center distance between detector array 1 and detector array 2. Therefore, the spacing between the detector arrays can be adjusted by adjusting the position of the beam reflecting surface, or the position of the beam reflecting surface can be adjusted based on the known spacing between the detector arrays. Specifically, this will be explained below in conjunction with the detector array details.

[0149] Figures 7 to 9 Several possible structures for optical simulation front-ends are listed, but no strict limitations are imposed; any structure falling under the above categories is acceptable. Figures 7 to 9 Any deformation of any structure falls within the protection scope of the embodiments of this application. For example, it can be modified... Figure 8 The structure shown can be modified, such as by increasing H3 or H6.

[0150] Based on the above scheme, the optical simulation front end allows for parallel beams incident on multiple detector arrays (e.g., two detector arrays), facilitating optical fabrication and back-end chip manufacturing. Furthermore, the spacing between the beam exit faces can be flexibly adjusted by changing the position of the beam reflecting surface, thereby flexibly adjusting the optical axis spacing of the multiple parallel beams output from the multiple beam exit faces. This approach makes the design, fabrication, and installation of the optical simulation front end more flexible and convenient. Moreover, since the position of the beam reflecting surface is related to the spacing between the detector arrays, it also reduces the requirements for the spacing between the back end and multiple detector arrays (e.g., two detector arrays), broadening its applicability.

[0151] The above examples illustrate the optical analog front-end scheme; the following section describes the scheme for the detector array.

[0152] Aspect 2, detector array.

[0153] In a balanced array receiver structure, multiple detector arrays can be designed, each array performing its own photoelectric conversion and outputting an electrical signal. For example, in this embodiment, these multiple detector arrays can be referred to as a balanced detector array. The photosensitive surfaces of the multiple detector arrays can be perpendicular to the incident direction of the mixed light. Figures 4 to 6 As shown, S PD1 After reflection by the beam reflecting surface, the light is incident on detector array 1. Detector array 1 targets S. PD1 Perform photoelectric conversion and output an electrical signal to the ROIC; S PD2 After being reflected by the beam reflecting surface, the light is incident on detector array 2. Detector array 2 targets S. PD2 It performs photoelectric conversion and outputs an electrical signal to ROIC.

[0154] As an example and not a limitation, the detector can be a photodetector (PD). A photodetector can use the photoelectric effect of materials to convert an input optical signal into an electrical signal output.

[0155] Optionally, the number of detector arrays can be greater than or equal to 2. For ease of understanding, this application embodiment mainly uses 2 detector arrays as an example for illustrative purposes. To distinguish them, these 2 detector arrays are referred to as detector array 1 and detector array 2.

[0156] Optionally, multiple detector arrays can also be located on the same horizontal plane. This approach facilitates the manufacturing of detector array chips and ROIC chips (the wafers for manufacturing the chips and the PCB boards for connecting the chips are all on the same plane), facilitates integration, and reduces engineering installation complexity.

[0157] Optionally, multiple detector arrays can adopt the same design, or in other words, multiple identical detector arrays can be designed within a balanced array receiver structure. It should be understood that in practical applications, different detector arrays can also be designed according to actual needs, and this is not limited.

[0158] Optionally, each detector array has the same number of pixels, that is, each detector array has the same number of single-tube detectors.

[0159] There are many ways to connect the detector array and the signal demodulation unit in the ROIC. Two possible design methods are introduced below.

[0160] Possible design approach 1: The output of each pair of pixels in detector array 1 and detector array 2 can be connected to the signal demodulation unit in the ROIC. In other words, the output of a single detector on detector array 1 and the output of a single detector on detector array 2 are input to the same signal demodulation unit in the ROIC, such as... Figure 10 As shown.

[0161] In a possible design approach 2, the output terminals of multiple pixels in detector array 1 and multiple pixels in detector array 2 can be connected to the signal demodulation unit in the ROIC. In other words, the multiple detector output terminals on detector array 1 and the multiple detector output terminals on detector array 2 are input to the same signal demodulation unit in the ROIC, such as... Figure 11 As shown.

[0162] For example, based on possible design approach 2, it can be implemented using a switch, such as Figure 11 As shown. Figure 11 As shown, each single-tube detector in detector array 1 is connected to one end of a switch, which, for distinction, is referred to as the first end of the first switch. Similarly, each single-tube detector in detector array 2 is connected to one end of a switch, which, for distinction, is referred to as the first end of the second switch. The other ends of the switches to which the single-tube detectors in each row or column of detector array 1 are connected in parallel (referred to as the second end of the first switch) and connected to the signal demodulation unit on the ROIC. Similarly, the other ends of the switches to which the single-tube detectors in each row or column of detector array 2 are connected in parallel (referred to as the second end of the second switch) and connected to the signal demodulation unit on the ROIC. As an example, as... Figure 11As shown, in detector array 1, the other ends of the switches connected to the single-tube detectors in each row are connected in parallel and then connected to the signal demodulation unit on the ROIC; in detector array 2, the other ends of the switches connected to the single-tube detectors in each row are also connected in parallel and then connected to the same signal demodulation unit. In this way, at any given time, or each time, only the switches of a certain column or row can be turned off, so that the signal output from the detector connected to the switch of that closed column or row is input to the back-end ROIC signal demodulation unit.

[0163] It should be understood that Figure 10 and Figure 11 Two possible structures for the detector array are listed, but no strict limitations are imposed. Any structure falling into the above categories is permissible. Figure 10 or Figure 11 All variations of the structure shown fall within the protection scope of the embodiments of this application. For example, it may also include a larger number of detector arrays.

[0164] As an example, and not a limitation, the circuit delays can be consistent, so that the electrical signals output from different detectors arrive at the signal demodulation unit as simultaneously as possible. The signal demodulation unit in the ROIC is used to perform a series of processing on the electrical signals, which will be explained below in conjunction with the introduction to the ROIC.

[0165] For ease of description, in the embodiments of this application, L is used to represent the spacing between detector array 1 and detector array 2, such as Figure 10 The distance L shown is an example, not a limitation. The center-to-center distance between detector array 1 and detector array 2 can be used to represent the spacing between detector array 1 and detector array 2. It should be understood that other ways of representing the spacing between detector array 1 and detector array 2 are also applicable to the embodiments of this application. The following description mainly uses the center-to-center distance between detector array 1 and detector array 2 as an example.

[0166] Optionally, the spacing between detector array 1 and detector array 2 is equal to the spacing between the optical axes of the two parallel beams output from the two beam exit faces. For example... Figures 4 to 6 As shown, L and S PD1 and S PD2 The optical axes are spaced equally.

[0167] In this embodiment, the position of the beam reflecting surface is related to the spacing between the detector arrays. Alternatively, the spacing between the detector arrays corresponds to the spacing between the beam reflecting surfaces, and / or the spacing between the beam reflecting surface and the beam splitting surface.

[0168] In one possible design, the spacing between the detector arrays, the spacing between the beam splitting surface and the beam reflecting surface parallel thereto, and the spacing between the two parallel beam reflecting surfaces correspond to each other. For example, the spacing between the detector arrays, the spacing between the beam reflecting surface and the beam splitting surface, and the spacing between the two parallel beam reflecting surfaces can satisfy the following relationship:

[0169] H0+H6-M<L<H0+H6+M, or, (H0-H3)+(H6-H9)-M<L<(H0-H3)+(H6-H9)+M.

[0170] For example, L=H0+H6, or, L=(H0-H3)+(H6-H9);

[0171] wherein L represents the center distance between the detector arrays; H0 represents the spacing between the beam splitting surface and the first beam reflecting surface parallel thereto; H6 represents the longest spacing between the two parallel second beam reflecting surfaces; H3 represents the shortest spacing between the two parallel first beam reflecting surfaces; and H9 represents the shortest spacing between the two parallel second beam reflecting surfaces.

[0172] It should be understood that, in actual products, the spacing between the detector arrays or the size of the detector arrays can be designed based on the structure of the optical simulation front end, such as based on the positions of the beam reflecting surfaces. The specific value of L is not strictly limited, as long as the mixed beam can be input to the detector arrays by designing the value of L.

[0173] The following will be described in two cases.

[0174] In one case, H0=H6, and H3=H9.

[0175] For example, as shown in FIG. 1, the optical simulation front end can be designed as shown in FIG. 2. Figure 7 For example, as shown in FIG. 1, the optical simulation front end can be designed as shown in FIG. 2. Figure 4 In this example, H0=H6, and L=2·H0. As can be seen from FIG. 2 and FIG. 3, in this example, L Figure 4 Figure 7 In this example, L min =2·H2, that is, H0=H2, and L=2·H2.

[0176] In this example, by adjusting the horizontal distance H0 between the beam splitting surface and the beam reflecting surface 1, and the horizontal distance H0 between the beam reflecting surface 2 and the beam reflecting surface 3 in the optical simulation front end, the center distance L of the detector array 1 and the detector array 2 can be changed. Alternatively, the optical simulation front end can also be designed according to the existing size of the detector array.

[0177] For another example, as shown in FIG. 4, the optical simulation front end can be designed as shown in FIG. 5. Figure 8 ​As shown in the optical analog front end, the planar balanced receiver structure can be as shown in Figure 5 In this example, H0=H6, H3=H9, and L=2(H0-H3).

[0178] In this example, the center distance of the detector array 1 and the detector array 2 can be changed by adjusting the size of H0 or H3 alone, or adjusting the size of H0 and H3 simultaneously. Alternatively, the optical analog front end can also be designed according to the existing detector array scale and size. For example, increasing H3 can reduce L, as shown in Figure 9 and the planar balanced receiver structure as shown in Figure 4 .

[0179] In another case, H0≠H6, H3≠H9.

[0180] An example is taken from the optical analog front end as shown in Figure 12 and the structure of the detector array. In the optical analog front end as shown in Figure 12 , 1 beam splitting surface and 11 beam reflecting surfaces can be included. For distinction, the 11 beam reflecting surfaces are respectively referred to as beam reflecting surface 1 (such as Ref1 in Figure 12 ), beam reflecting surface 2 (such as Ref2 in Figure 12 ), beam reflecting surface 3 (such as Ref3 in Figure 12 ), beam reflecting surface 4 (such as Ref4 in Figure 12 ), beam reflecting surface 5 (such as Ref5 in Figure 12 ), beam reflecting surface 6 (such as Ref6 in Figure 12 ), beam reflecting surface 7 (such as Ref7 in Figure 12 ), beam reflecting surface 8 (such as Ref8 in Figure 12 ), beam reflecting surface 9 (such as Ref9 in Figure 12 ), beam reflecting surface 10 (such as Ref 10 in Figure 12 ), and beam reflecting surface 11 (such as Ref 11 in Figure 12 ). As shown in Figure 12 , among the beam reflecting surface 6, the beam reflecting surface 7, the beam reflecting surface 8, the beam reflecting surface 9, the beam reflecting surface 10, and the beam reflecting surface 11, the longest distance H6 between the two parallel beam reflecting surfaces is the distance between the beam reflecting surface 6 and the beam reflecting surface 7, and the shortest distance H9 between the two parallel beam reflecting surfaces is the distance between the beam reflecting surface 10 and the beam reflecting surface 11. Among the beam reflecting surface 1, the beam reflecting surface 2, the beam reflecting surface 3, the beam reflecting surface 4, and the beam reflecting surface 5, the shortest distance H3 between the two parallel beam reflecting surfaces is the distance between the beam reflecting surface 4 and the beam reflecting surface 5.

[0181] In this example, the center distance L between detector array 1 and detector array 2 can be changed by adjusting the horizontal distance H0 between the beam splitter and beam reflecting surface 1 in the optical simulation front end, and the spacing between the beam reflecting surfaces (such as H3, H6, H9). Alternatively, the optical simulation front end can be designed according to the existing detector array size and dimensions.

[0182] It should be understood that the above two cases are merely illustrative examples and are not intended to limit the scope of the design. For example, it is also possible to design H0 = H6 and H3 ≠ H9; or, it is also possible to design H0 ≠ H6 and H3 = H9, etc., without limiting the scope of the design.

[0183] It should also be understood that the above examples are merely illustrative and are not intended to be limiting. For example, L and M can satisfy certain relationships, such as L being less than or equal to M, etc. Figure 6 As shown ( Figure 6 In this context, L can be equal to M; or L can be greater than M, such as... Figure 4 or Figure 5 As shown. L can also be equal to M. As an example rather than a limitation, we can design H3 = H0 - M / 2 and H9 = H0 - M / 2, then L can reach the minimum value M.

[0184] It should also be understood that the specific correspondence between L and H0, H3, H6, and H9 is not strictly limited. For example, L = f(H0), or L = f(H3), or L = f(H6), or L = f(H9), etc., are not limited in this respect. As long as the position of the beam reflecting surface is designed so that the mixed beam can be input into the detector array, it is applicable to the embodiments of this application.

[0185] Based on the above scheme, the structure of the optical simulation front end can be flexibly designed according to the size of the detector array and the center-to-center distance. In practical applications, the center-to-center distance between the two detector arrays can be minimized as much as possible, depending on the size of the detector array and the processing capability. This helps to reduce the size of the detector array and ROIC, thereby reducing costs and improving integration.

[0186] The above examples illustrate the solutions for optical analog front-ends and detector arrays. The following section introduces the solution for ROIC.

[0187] Aspect 3, ROIC.

[0188] ROICs can be connected to detector arrays to read out the electrical signals converted by the detector arrays in a specific manner for subsequent processing. ROICs can operate in various modes, including but not limited to: serial readout pixel by pixel, serial readout column by column, serial readout row by row, parallel readout pixel by pixel, parallel readout column by column, and parallel readout row by row.

[0189] Optionally, the number of ROICs can be less than or equal to the number of detector arrays. For example, two detector arrays can share one ROIC. This reduces the number of ROICs and circuit complexity, thereby lowering costs.

[0190] The ROIC includes multiple signal demodulation units.

[0191] As an example, the number of signal demodulation units on the ROIC is equal to the number of pixels on detector array 1 and detector array 2, such as... Figure 10 As shown, the output of each pair of pixels in detector array 1 and detector array 2 can be connected to a signal demodulation unit in ROIC. Therefore, the number of signal demodulation units on ROIC is equal to the number of pixels on detector array 1 and the number of pixels on detector array 2.

[0192] Another example is that the number of signal demodulation units on the ROIC is less than the number of pixels on detector array 1 and detector array 2, such as... Figure 11 As shown, the output terminals of multiple pixels in detector array 1 and multiple pixels in detector array 2 can be connected to a signal demodulation unit in ROIC. Therefore, the number of signal demodulation units on ROIC can be less than the number of pixels on detector array 1 or less than the number of pixels on detector array 2.

[0193] Each signal demodulation unit on the ROIC may include, but is not limited to, modules containing differential, DC blocking, envelope detection, delay, multiplication / mixing, integration, and analog-to-digital converter (ADC) modules, such as... Figure 13 As shown, the electrical signal passes through the signal demodulation unit and data processing in the ROIC, outputting a 3D image of the target object.

[0194] like Figure 13 As shown, the electrical signal I output by the i-th pixel in detector array 1 PD1_i The electrical signal I output by the i-th pixel in detector array 2 PD2_i Connected to the ROIC signal demodulation unit. In the demodulation unit, the signal first passes through a differential circuit, outputting (I... PD1_i -I PD2_i ) or (I PD2_i -I PD1_i Then, the differential output passes through a DC blocking circuit to eliminate the DC component. Next, the DC-blocked output passes through an envelope detector circuit to extract the envelope signal. The reference electrical signal (cos[w]) m The delay signal (cos[w]) is obtained by passing through a delay module, with the delay amount denoted as x. m(t+x)). The delayed drive signal and the aforementioned envelope signal enter the mixer / multiplier circuit. The mixer / multiplier output enters the integrator circuit to obtain the integral value. The integral value is sampled and digitized by the ADC, and then processed by back-end signal processing to solve for the time of flight. An ADC is an electronic component that converts an input analog electrical signal into a digital signal output, which is then used for digital signal processing.

[0195] It should be understood that the above is merely an illustrative example, and no strict limitations are made on the specific processing flow or the various modules included in the signal demodulation unit. For example, the signal demodulation unit may include more modules. Furthermore, the aforementioned modules may be replaced with other modules capable of achieving the same function. Also, some steps may be added or removed from the above processing steps, as long as the flight time can be calculated at the end.

[0196] Based on the above scheme, multiple detector arrays can share a single ROIC, which helps reduce the number of ROICs and circuit complexity, thereby reducing costs.

[0197] It should be understood that the solutions described in each of the above aspects can be used individually or in combination, without limitation. For example, in a lidar system, the optical analog front-end solution as described in aspect 1, the detector array solution as described in aspect 2, and the ROIC solution as described in aspect 3 can be used. As another example, in a lidar system, the optical analog front-end solution described in aspect 1 can be used, while the detector array solution and the ROIC solution can be flexibly designed based on the optical analog front-end solution. As yet another example, in a lidar system, the detector array solution described in aspect 2 can be used, while the solution for how the mixed light is input into the detector array and how the electrical signal is processed can be flexibly designed according to actual needs.

[0198] The preceding sections introduced the optical analog front-end, detector array, and ROIC solutions. For ease of understanding, the complete process of a balanced array receiver is briefly described below.

[0199] A specific example, with Figure 4 The illustrated array balanced receiver is used as an example for explanation. Figure 4 The structure of the optical analog front end in the area array balanced receiver shown is as follows: Figure 7 As shown. In practical applications, the processing of a balanced array receiver may include the following steps.

[0200] Step 1: The local oscillator light and the echo light are incident on the optical simulation front end.

[0201] Local oscillator (e.g., denoted as E) LO) After the mirror group 1 processing, the parallel light beam is incident to the optical simulation front end at mutually perpendicular angle directions. The echo light (as denoted by E S ) After the mirror group 2 processing, the parallel light beam is incident to the optical simulation front end at mutually perpendicular angle directions.

[0202] Referring to the optical simulation front end shown in Figure 7 , the local oscillator light is incident from the light beam incident end face 1, and the echo light is incident from the light beam incident end face 2.

[0203] The light beam splitting face left side optical path part: a1% transmitted echo light and b1% reflected local oscillator light are combined to obtain S PD1 . Both a1 and b1 are numbers greater than 0 and less than 100. Referring to the optical simulation front end shown in Figure 7 , S PD1 is output from the light beam exit end face 1 after being reflected by the light beam reflection face 1, and is still a parallel plane light beam. In an example, assuming that a1 and b1 are both 50,

[0204] The light beam splitting face right side optical path part: a2% reflected echo light and b2% transmitted local oscillator light are combined to obtain S PD2 . Both a2 and b2 are numbers greater than 0 and less than 100, and a1+a2≤100, b1+b2≤100. For example, a1 and a2 are both 50; or for example, b1 and b2 are both 50. Referring to the optical simulation front end shown in Figure 7 , S PD2 is output from the light beam exit end face 2 after being reflected by the light beam reflection face 2 and the light beam reflection face 3, and is still a parallel plane light beam. In an example, assuming that a2 and b2 are both 50,

[0205] Step 2, the combined light is incident to the detector array.

[0206] The combined light is output in parallel from the two light beam exit ends of the optical simulation front end. The combined light S PD1 propagates in parallel with the combined light S PD2 . S PD1 is incident to the detector array 1, S PD2 is incident to the detector array 2, and S PD1 is incident in a direction perpendicular to the light sensitive surface of the detector array 1, S PD2 is incident in a direction perpendicular to the light sensitive surface of the detector array 2.

[0207] In an example, the optical axes of the parallel plane light beam S PD1 and the parallel plane light beam S PD2 are separated by a distance equal to the center separation of the detector array 1 and the detector array 2.

[0208] For example, S PD1 The optical path length from the beam splitter surface to detector array 1 is equal to S. PD2 The optical path from the beam splitter surface to the detector array 2.

[0209] For example, a parallel plane beam S PD1 The spot size covers all pixels of detector array 1, and the parallel beam S PD2 The spot size covers all pixels of detector array 2.

[0210] Step 3: The detector array performs photoelectric conversion.

[0211] Each pixel in detector array 1 will receive light S PD1 Converting to an electrical signal, without loss of generality, let's assume the electrical signal output by the i-th pixel in detector array 1 is I. PD1_i .

[0212] Each pixel in detector array 2 will receive light S PD2 Converted into an electrical signal. Without loss of generality, assume that the electrical signal output by the i-th pixel in detector array 2 is I. PD2_i .

[0213] Step 4: The electrical signal output by the detector array is input to the ROIC.

[0214] The output of each pair of pixels in detector array 1 and detector array 2 is connected to the signal demodulation unit in the ROIC array. Figure 11 The following explanation uses a single signal demodulation unit structure in the ROIC shown as an example. Step 4 may include the following steps.

[0215] (1) The electrical signal I output by the i-th pixel in detector array 1 PD1_i The electrical signal I output by the i-th pixel in detector array 2 PD2_i Connect to the ROIC signal demodulation unit.

[0216] (2) In the signal demodulation unit, the signal first passes through a differential circuit, and the output (I) is then processed. PD1_i -I PD2_i ) or (I PD2_i -I PD1_i ).

[0217] (3) The above differential output passes through a DC blocking circuit to eliminate the DC component, and the output I... BPD .

[0218] (4) The above DC blocking output is passed through the envelope detector circuit to extract the envelope signal I. BPD_env .

[0219] (5) The reference electrical signal is delayed by a delay module with a delay amount of x, resulting in the delayed drive signal cos[w]. m (t+x)]. This delayed drive signal is related to the aforementioned envelope signal I. BPD_env Enter the mixer / multiplier circuit.

[0220] (6) The above mixing / multiplication output enters the integrating circuit to obtain the integral value C(x). The delay amount of the delay module is set to x0 = 0. (T m (where is the period of the envelope signal mentioned above). Four integral values ​​are obtained: C0 = C(x0), C1 = C(x1), C2 = C(x2), and C3 = C(x3).

[0221] (7) The above four integral values ​​are sampled and digitized by the ADC, and then processed by the back-end signal to solve for the flight time.

[0222] Through the above steps, a 3D image of the target object can be output.

[0223] For details not described in the above steps, please refer to the descriptions in aspects 1 to 3 above, which will not be repeated here.

[0224] The above text combined Figure 4 This section introduces the optical simulation front-end, detector array, and ROIC processing workflow. The following section combines... Figure 14 This paper introduces a specific process of a lidar based on heterodyne coherent detection provided in the embodiments of this application.

[0225] First, the laser emitted by the laser is split into two laser beams by the beam splitter.

[0226] After passing through the frequency shifter, one laser beam becomes the local oscillator E. LO , After frequency shifting, the local oscillator light is shaped into a parallel beam by a mirror group and then input into a balanced array receiver.

[0227] The other laser beam, after passing through an intensity modulator, becomes the emitted beam A. S ·cos(w m ·t)·exp[j·w c ·t], the modulation (driving) electrical signal of the intensity modulator is cos(w m ·t). Simultaneously, the driver generates a reference electrical signal that is input to the area array balanced receiver.

[0228] Among them, w IF This indicates the frequency shift amount produced by the frequency shifter. m This indicates the modulation frequency, typically in the range of kHz to MHz. T m Indicates the modulation period. wc represents the frequency of the optical carrier, for example, the frequency of the optical wave of a 905 nanometer (nm) wavelength laser is about 331 THz, 331 THz = 3.31 x 10 14 Hz. j is the imaginary unit. A LO represents the amplitude of the local oscillator light, A S represents the amplitude of the echo light.

[0229] Second, the echo light reflected by the target object passes through the receiving lens and is shaped into a parallel light beam, and is input into the area array balanced receiver.

[0230] The echo light reflected by the target object passes through the receiving lens and is shaped into a parallel light beam, and is input into the area array balanced receiver. S , The echo light reflected by the target object passes through the receiving lens and is shaped into a parallel light beam, and is input into the area array balanced receiver.

[0231] Third, the echo light and the local oscillator light are incident on the area array balanced receiver.

[0232] The processing of the area array balanced receiver can refer to steps 1 to 4 described above, and will not be described here again.

[0233] Fourth, output the 3D image.

[0234] Through the above steps, the distance of the target object can be obtained.

[0235] The above Figure 14 The above describes an example of a possible process for measuring distance by laser radar, which is not strictly limited. In actual applications, other operations can be added in the above steps according to actual needs.

[0236] In the above embodiments, the time of flight is mentioned several times. In the embodiments of the present application, the time of flight is indirect time of flight (iTOF). iTOF is a distance measurement method, for example, the time of flight of a wave (such as an optical wave) can be solved by the phase difference between the emitted wave (such as an optical wave) and the received wave (such as an optical wave) reflected by the target object. Wherein, Δφ represents that the phase delay generated by the signal once returning to the measuring line is less than π; c represents the speed of light in the atmosphere. Since the direct measurement quantity of this method is the phase difference, not the time difference, it is called indirect time of flight.

[0237] It should be understood that in some of the above embodiments, the specific values mentioned with respect to the distance, such as the specific values of H1, H2, H3, H4, M, L, etc., are not strictly limited. In actual applications, the corresponding values can be designed according to the needs.

[0238] It should also be understood that in some of the above embodiments, the example is exemplarily described by taking 2 detector arrays as an example, and the example is not limited thereto. For example, a larger number of detector arrays can also be included.

[0239] It should also be understood that in some of the above embodiments, the example is exemplarily described by mainly taking H0=H6 and H3=H9 as an example, and the example is not limited thereto. The case of H0≠H6 and / or H3≠H9 is also applicable to the embodiments of the present application.

[0240] It should also be understood that in some of the above embodiments, the example is exemplarily described by taking 2 beam incidence end faces and 2 beam emission end faces as an example, and the example is not limited thereto. For example, a larger number of beam incidence end faces and beam emission end faces can also be included. In addition, the beam incidence end face and the beam emission end face are defined for the convenience of description, and the naming does not limit the protection scope of the embodiments of the present application.

[0241] It should also be understood that in some of the above embodiments, some corresponding relationships are listed, such as L=2H0. In actual application, there can be a slight offset, such as L=2H0+Δ.

[0242] It should also be understood that in some of the above embodiments, as shown in the structure of Figures 4 to 6 The detector array (such as the detector array 1 and the detector array 2) is consistent with the width of the beam propagation region, and the example is not strictly limited thereto. For example, the width of the detector array (such as the detector array 1 and the detector array 2) can be greater than the width of the beam propagation region, as long as the beam can be input to the detector array. For another example, the width of the detector array (such as the detector array 1 and the detector array 2) can be less than the width of the beam propagation region, as long as the beam can be input to the detector array.

[0243] It should also be understood that the division of the functional modules of the optical analog front end, the detector array, the readout circuit and the like in the embodiments of the present application is illustrative, and in actual implementation, there can be another division mode. In an example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. For example, the mirror group can also belong to the module of the optical analog front end. In another example, each functional module can be divided according to each function, or two or more functions can be integrated in one module. In addition, each of the above modules can be realized in the form of hardware or in the form of a software functional module.

[0244] It should also be understood that the specific structure listed above, such as the structure of the area array balanced receiver shown in Figures 4 to 6 For another example, Figures 7 to 9 the structure of the optical analog front end shown in Figures 10 to 12The structure of the two detector arrays shown is exemplary, and any variation of the structure described above or any structure that can achieve the functions described above falls within the protection scope of the embodiments of the present application. For example, Figure 15 A schematic diagram of a laser radar system 1500 suitable for the embodiments of the present application is shown. As Figure 15 The laser radar system 1500 described can include a transmitting module 1510 and a receiving module 1520. The transmitting module 1510 is configured to transmit a light beam. The receiving module 1520 is configured to process a received light beam.

[0245] By way of example, the transmitting module 1510 is configured to transmit a light beam to obtain echo light and local light.

[0246] By way of example, the receiving module 1520 includes a beam splitting module 1521, a first light beam reflection module 1522, a second light beam reflection module 1523, a first conversion module 1524, a second conversion module 1525, and a processing module 1526.

[0247] In one possible manner, the beam splitting module 1521 is configured to combine the received echo light and local light to obtain a first path mixed light beam and a second path mixed light beam; the first light beam reflection module 1522 is configured to reflect the first path mixed light beam so that the first path mixed light beam is input to the first conversion module 1524; the second light beam reflection module 1523 is configured to reflect the second path mixed light beam so that the second path mixed light beam is input to the second conversion module 1525; the first conversion module 1524 is configured to convert the first path mixed light beam into a first path electrical signal; the second conversion module 1525 is configured to convert the second path mixed light beam into a second path electrical signal; and the processing module 1526 is configured to process the first path electrical signal and the second path electrical signal; wherein the distance between the first conversion module 1524 and the second conversion module 1525 corresponds to the distance between the beam splitting module 1521 and the first light beam reflection module 1522 parallel thereto, and the distance between the two second light beam reflection modules 1523 parallel to each other.

[0248] The beam splitting module 1521, the first light beam reflection module 1522, and the second light beam reflection module 1523 can be used to achieve the functions of the optical analog front end described above, and the specific form or structure of the beam splitting module 1521, the first light beam reflection module 1522, and the second light beam reflection module 1523 is not limited.

[0249] The first conversion module 1524 and the second conversion module 1525 can be configured to perform photoelectric conversion. The first conversion module 1524 and the second conversion module 1525 can be configured to implement the functions of the detector arrays described above, for example, the first conversion module 1524 is configured to implement the functions of the first detector array, and the second conversion module 1525 is configured to implement the functions of the second detector array. The specific form or structure of the first conversion module 1524 and the second conversion module 1525 is not limited.

[0250] The processing module 1526 can be configured to perform a series of processing on the output electrical signals. For example, the processing module 1526 can be configured to perform a series of processing on the first electrical signal output by the first conversion module 1524 and the second electrical signal output by the second conversion module 1525. The processing module 1526 can be configured to implement the functions of the readout circuit described above, and the specific form or structure of the processing module 1526 is not limited.

[0251] It should be understood that Figure 15 The laser radar system 1500 shown is described by way of example by dividing various functional modules corresponding to various functions, and the division of modules in the laser radar system 1500 is illustrative and is only a logical functional division. In actual implementation, there can be another division manner. In addition, the laser radar system 1500 can further include other more modules, and the laser radar system 1500 is not limited in this regard.

[0252] Based on the above technical solutions, the detection sensitivity of the laser radar, especially the Flash laser radar system, can be improved, the problem of low detection sensitivity of the prior art is solved, and the detection range of the laser radar, especially the Flash laser radar, is increased.

[0253] Each embodiment described herein can be an independent solution or can be combined according to the inherent logic, and these solutions all fall within the protection scope of the present application.

[0254] The device embodiments of the present application are described in detail above in combination with Figures 2 to 15 The method embodiments of the present application are described in detail below in combination with Figure 16 The description of the device side and the description of the method side correspond to each other, and the repeated description is appropriately omitted for brevity.

[0255] Figure 16 is a schematic flowchart of the light detection method provided by some embodiments of the present application. Figure 16 The method 1600 can be performed by the area array balanced receiver mentioned above. The method 1600 can include the following steps.

[0256] 1610, the received echo light and the local oscillator light are combined to obtain a first mixed light beam and a second mixed light beam;

[0257] 1620, the first mixed light beam is reflected by the first light beam reflecting surface and input to the first detector array;

[0258] 1630, the second mixed light beam is reflected by the second light beam reflecting surface and input to the second detector array;

[0259] 1640, the first detector array converts the first mixed light beam into a first electrical signal;

[0260] 1650, the second detector array converts the second mixed light beam into a second electrical signal, wherein the spacing between the first detector array and the second detector array corresponds to the spacing between the beam splitting surface and the first light beam reflecting surface parallel to the beam splitting surface, and the spacing between the two second light beam reflecting surfaces parallel to each other;

[0261] 1660, the readout circuit processes the first electrical signal output by the first detector array and the second electrical signal output by the second detector array, and outputs the processed result.

[0262] In some embodiments, the first mixed light beam and the second mixed light beam are parallel light beams.

[0263] In some embodiments, the propagation direction of the first mixed light beam is perpendicular to the light-sensitive surface of the first detector array, and the propagation direction of the second mixed light beam is perpendicular to the light-sensitive surface of the second detector array.

[0264] In some embodiments, the beam splitting surface reflects and transmits the received echo light, and reflects and transmits the received local light; the first mixed light beam is the light beam after the reflected echo light and the transmitted local light are combined, and the second mixed light beam is the light beam after the transmitted echo light and the reflected local light are combined.

[0265] In some embodiments, the difference between the optical path from the beam splitting surface to the first detector array of the first mixed light beam and the optical path from the beam splitting surface to the second detector array of the second mixed light beam is related to the heterodyne period and the speed of light; or the difference between the optical path from the beam splitting surface to the first detector array of the first mixed light beam and the optical path from the beam splitting surface to the second detector array of the second mixed light beam is less than (heterodyne period * speed of light / f), wherein f is a constant.

[0266] In some embodiments, any two first light beam reflecting surfaces are parallel or perpendicular to each other; and / or, any two second light beam reflecting surfaces are parallel or perpendicular to each other.

[0267] In some embodiments, the spacing between the first detector array and the second detector array corresponds to the spacing between the beam splitting surface and the first light beam reflecting surface parallel to the beam splitting surface, and the spacing between the two second light beam reflecting surfaces parallel to each other, including the spacing between the first detector array and the second detector array, the spacing between the beam splitting surface and the first light beam reflecting surface parallel to the beam splitting surface, and the spacing between the two second light beam reflecting surfaces parallel to each other, satisfy the following relationship:

[0268] (H0-H3)+(H6-H9)-M<L<(H0-H3)+(H6-H9)+M;

[0269] wherein L represents the center distance between the first detector array and the second detector array; H0 represents the spacing between the beam splitting surface and the first light beam reflecting surface parallel to the beam splitting surface; H6 represents the longest spacing between the two second light beam reflecting surfaces parallel to each other; H3 represents the shortest spacing between the two first light beam reflecting surfaces parallel to each other; H9 represents the shortest spacing between the two second light beam reflecting surfaces parallel to each other; and M represents the cross-sectional spot size of the first mixed light beam or the second mixed light beam.

[0270] In some embodiments, the spacing between any two first light beam reflecting surfaces is greater than or equal to the cross-sectional spot size of the first mixed light beam, and the spacing between any two second light beam reflecting surfaces is greater than or equal to the cross-sectional spot size of the second mixed light beam.

[0271] In some embodiments, the plane in which the first mixed light beam is input to the first detector array and the plane in which the second mixed light beam is input to the second detector array are the same plane.

[0272] In some embodiments, the number of single-tube detectors in the first detector array and the number of single-tube detectors in the second detector array are the same.

[0273] In some embodiments, the first detector array and the second detector array are both connected to a readout circuit.

[0274] In some embodiments, the readout circuit includes a plurality of signal demodulation units; each signal demodulation unit is connected to one single-tube detector in the first detector array and one single-tube detector in the second detector array, and each signal demodulation unit processes the electrical signal output by the single-tube detector connected to the signal demodulation unit.

[0275] In some embodiments, the readout circuit includes a plurality of signal demodulation units; each single-tube detector in the first detector array is connected to a first end of a first switch, and each single-tube detector in the second detector array is connected to a first end of a second switch; each signal demodulation unit is connected to a second end of the plurality of first switches in the first detector array and a second end of the plurality of second switches in the second detector array; wherein the second ends of the plurality of first switches are connected in parallel, and the second ends of the plurality of second switches are connected in parallel.

[0276] The embodiments of the present application further provide a computer readable storage medium, which stores computer instructions for implementing the method executed by the optical detection system in the above embodiments.

[0277] For example, the computer program is executed by the detector array, so that the detector array can implement the conversion of the photoelectric signal.

[0278] For another example, the computer program is executed by the readout circuit (such as the signal demodulation unit), so that the readout circuit (such as the signal demodulation unit) can implement the processing of the signal.

[0279] The embodiments of the present application further provide a computer program product including instructions, which are executed by a computer to implement the processing steps in the above embodiments.

[0280] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the explanation and beneficial effects of the related content in any of the above methods can refer to the corresponding device embodiments provided above, and will not be repeated here.

[0281] The embodiments of the present application do not particularly limit the specific structure of the execution subject of the method provided by the embodiments of the present application, as long as the execution subject can perform detection according to the method provided by the embodiments of the present application by running the program in which the code of the method provided by the embodiments of the present application is recorded. For example, the execution subject of the method provided by the embodiments of the present application can be each module in the optical detection system, or a functional module in the each module which can call and execute the program.

[0282] In the embodiments described above, all or some of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or some of the embodiments can be implemented in the form of a computer program product storing computer program instructions. When the computer program instructions are loaded into and executed by a computer, all or some of the procedures or functions described in the embodiments of the present application are performed. The computer can be a general purpose computer, a special purpose computer, a computer network, or another programmable apparatus. The computer program instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer program instructions can be transmitted from a website, a computer, a server or a data center to another website, computer, server or data center through a wired (for example, coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (for example, infrared, wireless, microwave, etc.) manner. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media. The available media can be a magnetic medium (for example, floppy disk, hard disk, magnetic tape), an optical medium (for example, digital video disc (DVD)), or a semiconductor medium (for example, solid state disk (SSD)) and the like.

[0283] Those skilled in the art can appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. A skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0284] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0285] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiment of the present application according to actual needs.

[0286] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0287] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An optical detection system, characterized by Comprising: a beam splitting surface, a first beam reflecting surface, a second beam reflecting surface, a first detector array, a second detector array and a readout circuit; the beam splitting surface is configured to combine the received echo light and the local oscillator light to obtain a first mixed light beam and a second mixed light beam; the first beam reflecting surface is configured to reflect the first mixed light beam so that the first mixed light beam is input to the first detector array; the second beam reflecting surface is configured to reflect the second mixed light beam so that the second mixed light beam is input to the second detector array; the first detector array is configured to convert the first mixed light beam into a first electrical signal; the second detector array is configured to convert the second mixed light beam into a second electrical signal; the readout circuit is configured to process the first electrical signal output by the first detector array and the second electrical signal output by the second detector array, and output the processed result; wherein the spacing between the first detector array and the second detector array corresponds to the spacing between the beam splitting surface and the first beam reflecting surface parallel thereto, and the spacing between the two parallel second beam reflecting surfaces; wherein the difference between the optical path from the beam splitting surface to the first detector array of the first mixed light beam and the optical path from the beam splitting surface to the second detector array of the second mixed light beam is related to the heterodyne period and the speed of light.

2. The optical detection system according to claim 1, wherein: the propagation direction of the first mixed light beam is parallel to the propagation direction of the second mixed light beam.

3. The optical detection system according to claim 1, wherein: the propagation direction of the first mixed light beam is perpendicular to the light-sensitive surface of the first detector array, and the propagation direction of the second mixed light beam is perpendicular to the light-sensitive surface of the second detector array.

4. The optical detection system according to any one of claims 1 to 3, wherein: the beam splitting surface is configured to reflect and transmit the received echo light, and reflect and transmit the received local oscillator light; the first mixed light beam is the light beam after the reflected echo light and the transmitted local oscillator light are combined, and the second mixed light beam is the light beam after the transmitted echo light and the reflected local oscillator light are combined.

5. The optical detection system according to any one of claims 1 to 3, wherein: a difference between an optical path of the first hybrid light beam from the beam splitting face to the first array of detectors and an optical path of the second hybrid light beam from the beam splitting face to the second array of detectors is less than: a heterodyne period * the speed of light f wherein, f is a constant.

6. The optical detection system according to any one of claims 1 to 3, wherein: any two of the first beam reflecting surfaces are parallel or perpendicular to each other; and / or any two of the second beam reflecting surfaces are parallel or perpendicular to each other.

7. The optical detection system according to any one of claims 1 to 3, wherein the spacing between the first detector array and the second detector array corresponds to the spacing between the beam splitting surface and the first beam reflecting surface parallel thereto, and the spacing between the two parallel second beam reflecting surfaces, comprising: ​ The distance between the first probe array and the second probe array, the distance between the beam splitting surface and the first beam reflecting surface parallel to the beam splitting surface, and the distance between the two second beam reflecting surfaces parallel to each other satisfy the following relationship: , or ; Wherein, L represents the center distance between the first probe array and the second probe array; H0 represents the distance between the beam splitting surface and the first beam reflecting surface parallel to the beam splitting surface; H6 represents the longest distance between the two second beam reflecting surfaces parallel to each other; H3 represents the shortest distance between the two first beam reflecting surfaces parallel to each other; H9 represents the shortest distance between the two second beam reflecting surfaces parallel to each other; M represents the cross-sectional spot size of the first mixed beam or the second mixed beam.

8. The optical detection system of any one of claims 1 to 3, wherein, The distance between any two first beam reflecting surfaces is greater than or equal to the cross-sectional spot size of the first mixed beam, and the distance between any two second beam reflecting surfaces is greater than or equal to the cross-sectional spot size of the second mixed beam.

9. The light detection system according to any one of claims 1 to 3, wherein The plane where the first mixed beam is input to the first probe array and the plane where the second mixed beam is input to the second probe array are the same plane.

10. The light detection system according to any one of claims 1 to 3, wherein The number of single-tube detectors in the first probe array is the same as the number of single-tube detectors in the second probe array.

11. The light detection system according to any one of claims 1 to 3, wherein The first probe array and the second probe array are both connected to the readout circuit.

12. The optical detection system of any one of claims 1 to 3, wherein, The readout circuit includes a plurality of signal demodulation units; Each signal demodulation unit is connected to one single-tube detector in the first probe array and one single-tube detector in the second probe array. Each signal demodulation unit is configured to process the electrical signal output by the single-tube detector connected to the signal demodulation unit.

13. The light detection system according to any one of claims 1 to 3, wherein The readout circuit includes a plurality of signal demodulation units; Each single-tube detector in the first probe array is connected to the first end of a first switch, and each single-tube detector in the second probe array is connected to the first end of a second switch. Each signal demodulation unit is connected to the second end of a plurality of first switches in the first probe array and the second end of a plurality of second switches in the second probe array. The second ends of the plurality of first switches are connected in parallel, and the second ends of the plurality of second switches are connected in parallel.

14. A method of optical detection, the method comprising: The light detection method is applied to a light detection system, which includes a beam splitting surface, a first beam reflecting surface, a second beam reflecting surface, a first probe array, a second probe array, and a readout circuit. The light detection method includes: Combining the received echo light and the local oscillator light to obtain a first mixed beam and a second mixed beam; The first mixed light beam is reflected by the first light beam reflecting surface and input to the first detector array; The second mixed light beam is reflected by the second light beam reflecting surface and input to the second detector array; The first detector array converts the first mixed light beam into a first electrical signal; The second detector array converts the second mixed light beam into a second electrical signal; The readout circuit processes the first electrical signal output by the first detector array and the second electrical signal output by the second detector array and outputs a processed result; The spacing between the first detector array and the second detector array corresponds to the spacing between the beam splitting surface and the first light beam reflecting surface parallel thereto and the spacing between the two parallel second light beam reflecting surfaces. The difference between the optical path of the first mixed light beam from the beam splitting surface to the first detector array and the optical path of the second mixed light beam from the beam splitting surface to the second detector array is related to the heterodyne period and the speed of light.

15. The optical detection method according to claim 14, wherein: The propagation direction of the first mixed light beam is parallel to the propagation direction of the second mixed light beam.

16. The optical detection method of claim 14, wherein, The propagation direction of the first mixed light beam is perpendicular to the light-sensitive surface of the first detector array, and the propagation direction of the second mixed light beam is perpendicular to the light-sensitive surface of the second detector array.

17. The optical detection method according to any one of claims 14 to 16, wherein: The beam splitting surface reflects and transmits the received echo light and reflects and transmits the received local light; The first mixed light beam is the light beam after the reflected echo light and the transmitted local light are combined, and the second mixed light beam is the light beam after the transmitted echo light and the reflected local light are combined.

18. The optical detection method according to any one of claims 14 to 16, wherein: a difference between an optical path of the first hybrid light beam from the beam splitting face to the first array of detectors and an optical path of the second hybrid light beam from the beam splitting face to the second array of detectors is less than: a heterodyne period * the speed of light f wherein, f is a constant.

19. The optical detection method according to any one of claims 14 to 16, wherein: Any two first light beam reflecting surfaces are parallel or perpendicular to each other; and / or Any two second light beam reflecting surfaces are parallel or perpendicular to each other.

20. The optical detection method according to any one of claims 14 to 16, wherein: The spacing between the first detector array and the second detector array corresponds to the spacing between the beam splitting surface and the first light beam reflecting surface parallel thereto and the spacing between the two parallel second light beam reflecting surfaces, including: The spacing between the first detector array and the second detector array, the spacing between the beam splitting surface and the first light beam reflecting surface parallel thereto, and the spacing between the two parallel second light beam reflecting surfaces satisfy the following relationship: , or ; Wherein, L represents the center distance between the first probe array and the second probe array; H0 represents the distance between the beam splitting surface and the first beam reflecting surface parallel to it; H6 represents the longest distance between the two parallel second beam reflecting surfaces; H3 represents the shortest distance between the two parallel first beam reflecting surfaces; H9 represents the shortest distance between the two parallel second beam reflecting surfaces; M represents the cross-sectional spot size of the first or second mixed light beam.

21. The optical detection method of any one of claims 14-16, wherein, The distance between any two first beam reflecting surfaces is greater than or equal to the cross-sectional spot size of the first mixed light beam, and the distance between any two second beam reflecting surfaces is greater than or equal to the cross-sectional spot size of the second mixed light beam.

22. The optical detection method of any one of claims 14-16, wherein, The first mixed light beam is input into the plane where the first probe array is located, and the second mixed light beam is input into the plane where the second probe array is located.

23. The light detection method of any one of claims 14-16, wherein: The number of single-tube detectors in the first probe array is the same as the number of single-tube detectors in the second probe array.

24. The light detection method of any one of claims 14-16, wherein: The first probe array and the second probe array are both connected to the readout circuit.

25. The optical detection method of any one of claims 14-16, wherein, The readout circuit includes a plurality of signal demodulation units; Each signal demodulation unit is connected to one single-tube detector in the first probe array and one single-tube detector in the second probe array, Each signal demodulation unit processes the electrical signal output by the single-tube detector connected to it.

26. The light detection method of any one of claims 14-16, wherein: The readout circuit includes a plurality of signal demodulation units; Each single-tube detector in the first probe array is connected to the first end of a first switch, and each single-tube detector in the second probe array is connected to the first end of a second switch; Each signal demodulation unit is connected to the second end of a plurality of first switches in the first probe array and the second end of a plurality of second switches in the second probe array; Wherein, the second ends of the plurality of first switches are connected in parallel, and the second ends of the plurality of second switches are connected in parallel.

27. A lidar system, comprising: The laser radar system includes a transmitting module and a receiving module, The transmitting module is configured to emit a light beam; The receiving module is configured to receive the light beam and perform the light detection method of any one of claims 14-26.

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