Optical detection device and detection method

Abstract

The invention provides a light detection device and a detection method. The light detection device comprises a light emitter array, a light detector array and a control module. The light emitter array comprises a plurality of light emitters; the light emitter is configured to output an emission signal; the optical detector array comprises a plurality of optical detectors; the light detector is configured to detect an echo signal reflected after the emission signal encounters an obstacle; wherein the light emitter array and the light detector array form a plurality of detection channels, and each detection channel comprises at least one light emitter and at least one light detector. In the one-time signal transmission process from transmitting the transmitting signals to detecting the corresponding echo signals, the control module selects the preset light emitters to emit light at the same time, the view fields of the light emitters emitting light at the same time are not overlapped within the detection distance, and crosstalk between detection channels is effectively reduced.

Description

Technical Field

[0001] This application relates to the field of optical ranging technology, and in particular to optical detection devices and detection methods. Background Technology

[0002] A lidar (Light Detection and Ranging) system is a device that detects external objects by emitting laser light and receiving the echo signal that returns after the laser light reaches the surface of the target object. Therefore, a lidar system consists of a light emitting module and a light detection module.

[0003] Currently, the optical emission module of a lidar system includes a laser array, which comprises multiple lasers; correspondingly, the optical detection module includes a photodetector array, which comprises multiple photodetectors. At least one laser and at least one photodetector form a detection channel, and each detection channel corresponds to a field of view (FOV), also known as the field angle. Typically, the number of lines in a multi-line lidar system corresponds to the number of detection channels.

[0004] However, due to the need for system miniaturization, the layout space for laser arrays and photodetector arrays becomes very limited, resulting in a compact arrangement of lasers and photodetectors. During lidar scanning, if the lasers and photodetectors operate in parallel, crosstalk between detection channels can easily occur. For example, detection channel A might receive an echo signal from a detection point C within the field of view of detection channel B, even though point C might be outside the field of view of detection channel A. This would cause point C to appear in the detection results (e.g., in a point cloud image) at a location where it was not originally present; this phenomenon is known as "ghosting."

[0005] Even with some time-division emission and detection control, it is still difficult to effectively reduce crosstalk due to the high-frequency and high-speed detection required in applications such as autonomous driving.

[0006] In particular, with high-line-count lidar becoming the mainstream product development trend in the industry, such as lidar with 32 lines or more (e.g., 32 lines, 64 lines, 128 lines, 256 lines or even higher), crosstalk will become a major obstacle to its product development. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, this application provides a photodetector and a detection method to solve the problems of the prior art.

[0008] To achieve the above and other related objectives, a first aspect of this application provides a light detection device, comprising: a light emitter array including a plurality of light emitters; the light emitters being configured to output a transmitted signal; a light detector array including a plurality of light detectors; the light detectors being configured to detect an echo signal reflected after the transmitted signal encounters an obstacle; wherein the light emitter array and the light detector array constitute a plurality of detection channels, each detection channel including at least one light emitter and at least one light detector; a control module; during a single signal transmission process of sending a transmitted signal to detect a corresponding echo signal, the control module selects a predetermined plurality of light emitters to emit light simultaneously, the fields of view of the simultaneously emitting plurality of light emitters not overlapping within the detection distance.

[0009] In some embodiments of the first aspect, the light emitter array is a one-dimensional array or a two-dimensional array; wherein, when the light emitter array is a two-dimensional array, the ratio between its dimensions in the two dimensional directions is greater than 3 or greater than 5.

[0010] In some embodiments of the first aspect, the multiple activated optical emitters in the optical emitter array form multiple detection channels in operation with the multiple activated photodetectors in the photodetector array; the optical emitter array includes multiple groups of optical emitters and / or the photodetector array includes multiple groups of photodetectors; the activated optical emitters belong to different groups of optical emitters and / or the activated photodetectors belong to different groups of photodetectors.

[0011] In some embodiments of the first aspect, each optical transmitter in each optical transmitter group and / or each photodetector in each photodetector group is activated in turn during multiple signal transmissions.

[0012] In some embodiments of the first aspect, a first isolation range is provided between two optical transmitters in the same optical transmitter group; and / or, a second isolation range is formed between photodetectors activated in two adjacent photodetector groups during the same signal transmission.

[0013] In some embodiments of the first aspect, each optical emitter group includes a predetermined number of optical emitters, and the plurality of optical emitters of the optical emitter group are integrated on at least one chip.

[0014] In some embodiments of the first aspect, a plurality of optical emitters of the optical emitter group are coupled to at least one selection unit, which selects the optical emitters based on an external signal.

[0015] In some embodiments of the first aspect, the optical emitter array comprises N columns of optical emitters staggered from each other, each column of optical emitters extending along a first direction, where N > 1; and / or, the photodetector array comprises M columns of photodetectors staggered from each other, each column of photodetectors extending along the first direction, where M > 1.

[0016] In some embodiments of the first aspect, the signal characteristics of the optical signals transmitted in each detection channel are not completely identical during the same signal transmission process.

[0017] In some embodiments of the first aspect, the optical detection device includes: a control module, configured to determine whether the signal characteristics of the echo signal detected by the optical detector match the signal characteristics of the emitted signal of the optical transmitter of the corresponding detection channel, and, when matching, use the echo signal to calculate the distance to the target object in the corresponding detection channel.

[0018] In some embodiments of the first aspect, the transmitted signal emitted by the optical transmitter includes one or more pulse signals; the dimensions of the signal characteristics include one or more combinations of wavelength, pulse width, number of pulses, pulse peak value, and inter-pulse time interval.

[0019] In some embodiments of the first aspect, the signal characteristics in the pulse width dimension include: determining whether the signal characteristics of the echo signal match the signal characteristics of the transmitted signal based on the pulse width ratio between multiple pulses.

[0020] In some embodiments of the first aspect, the signal characteristics in the signal strength dimension include: determining whether the signal characteristics of the echo signal match the signal characteristics of the transmitted signal based on the intensity ratio between multiple pulses.

[0021] In some embodiments of the first aspect, the emitted signals of the optical transmitters in different detection channels operating during the same signal transmission process have different wavelengths; each of the different detection channels has a filter unit at its front, which allows only the echo signal of the corresponding wavelength of the detection channel to pass through.

[0022] In some embodiments of the first aspect, the control module is configured to control the optical transmitter array and the optical receiver array to continuously probe a detection channel multiple times during a single signal transmission to obtain a time-of-flight value, and to compare the time-of-flight values ​​obtained from the multiple probes to determine that the detection result of the channel is valid if the comparison matches; otherwise, the detection result is discarded.

[0023] In some embodiments of the first aspect, the optical detection device includes a lidar.

[0024] To achieve the above and other related objectives, a second aspect of this application provides a method for performing light detection using a light detection device as described in any of the first aspects, comprising: activating a plurality of light transmitters in the light transmitter array to transmit transmission signals; activating a plurality of light detectors in the light detector array; wherein the activated plurality of light transmitters and the activated plurality of light detectors respectively form a plurality of detection channels in an operational state; and each activated light transmitter belongs to a different light transmitter group and / or each activated light detector belongs to a different light detector group.

[0025] In summary, the optical detection device and method provided in this application constitute multiple detection channels between the optical emitter array and the optical detector array in the optical detection device. Each detection channel includes at least one optical emitter and at least one optical detector. In one embodiment, a detection channel may consist of one optical emitter and one optical detector; in other embodiments, a detection channel may consist of one optical emitter and several optical detectors; furthermore, multiple detection channels can also be used in the same embodiment. During a single signal transmission process of sending a transmission signal to the corresponding echo signal, multiple predetermined optical emitters are selected to emit light simultaneously. The fields of view of the multiple simultaneously emitting optical emitters do not overlap within the detection distance, ensuring sufficient spatial spacing between the simultaneously operating detection channels to effectively reduce crosstalk. Attached Figure Description

[0026] Figures 1 to 3 This application presents schematic diagrams illustrating the structure of lidar that may be implemented using a photodetector in various embodiments.

[0027] Figure 4A This illustration shows a frontal view of the arrangement of the light emitter array in one embodiment of this application.

[0028] Figure 4B Shown as Figure 4A A schematic diagram of the left-side partial structure.

[0029] Figure 4C Display according to Figure 4A The example structure is a schematic diagram of the division of the optical emitter group.

[0030] Figure 4D Display according to Figure 4C A schematic diagram showing how each group of light emitters emits light through multiple detection channels.

[0031] Figure 5A This illustration shows a schematic diagram of the principle of detection using wavelength as a signal feature in one embodiment of this application.

[0032] Figure 5BThis invention presents a waveform diagram in one embodiment of the present application, characterized by pulse width as a signal feature.

[0033] Figure 5C This illustration shows a waveform diagram with the inter-pulse time interval as a signal characteristic in one embodiment of this application.

[0034] Figure 6 A schematic diagram of the circuit structure of the driving circuit of the optical emitter array in one embodiment of this application is shown.

[0035] Figure 7 The diagram shows a waveform of the trigger signal of the drive circuit in one embodiment of this application, characterized by the number of pulses.

[0036] Figures 8A to 8D The diagram illustrates different waveforms of the trigger signals of different optical emitter groups in one embodiment of this application, characterized by pulse time intervals.

[0037] Figure 9 The diagram shows a waveform of the trigger signal of a detection channel in one embodiment of this application, characterized by pulse width. Detailed Implementation

[0038] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and application systems without departing from the spirit of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0039] The embodiments of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement the application. This application may be embodied in many different forms and is not limited to the embodiments described herein.

[0040] For the purpose of clearly describing this application, devices that are not relevant to the description are omitted, and the same or similar components throughout the specification are given the same reference numerals.

[0041] Throughout this specification, when it is said that a device is "connected" to another device, this includes not only "direct connection" but also "indirect connection" by placing other components in between. Furthermore, when it is said that a device "comprises" a certain constituent element, unless otherwise stated otherwise, this does not exclude other constituent elements, but rather implies that other constituent elements may be included.

[0042] When we say that a device is "above" another device, this can mean that it is directly above the other device, or it can mean that other devices are present in between. Conversely, when we say that a device is "directly" "above" another device, there are no other devices present in between.

[0043] Although the terms first, second, etc., are used in some instances herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, descriptions such as first interface and second interface, etc. Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” indicate the presence of the stated feature, step, operation, element, component, item, kind, and / or group, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms “or” and “and / or” as used herein are interpreted as inclusive, or mean any one or any combination thereof. Thus, “A, B, or C” or “A, B, and / or C” means “any one of: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition occur only when combinations of elements, functions, steps, or operations are inherently mutually exclusive in some way.

[0044] The technical terms used herein are for reference only to specific embodiments and are not intended to limit the scope of this application. The singular form used herein includes the plural form unless the statement explicitly indicates otherwise. The word "comprising" as used in the specification means to specify a particular characteristic, region, integer, step, operation, element, and / or component, and does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0045] Terms such as "below" and "above" indicating relative space are used to more easily explain the relationship of one device relative to another in the accompanying drawings. These terms refer not only to their meaning as shown in the drawings but also to other meanings or operations of the device in use. For example, if the device in the drawings is flipped, a device previously described as "below" another device may now be described as "above" another device. Therefore, the exemplary term "below" encompasses both above and below. The device may be rotated 90° or other angles, and the terms representing relative space are interpreted accordingly.

[0046] Although not explicitly defined, all terms, including technical and scientific terms used herein, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Terms defined in commonly used dictionaries shall be further interpreted as having a meaning consistent with the relevant technical literature and the content of this present application, and shall not be over-interpreted as having an ideal or overly formulaic meaning unless otherwise defined.

[0047] As mentioned earlier, the increasing miniaturization and integration of optical emitter arrays and photodetector arrays makes it easy for crosstalk to occur between detection channels in multi-beam lidar systems using them for detection. Although crosstalk can be reduced by time-division activation, the switching time between detection channels is too short for high-beam (more than 32 beams) lidar systems, making it difficult to effectively reduce crosstalk.

[0048] In view of this, this application can provide a photodetector device, which includes a photodetector array and a photodetector array. It can select photodetectors and / or photodetectors spaced far apart in the array and activate them simultaneously, effectively reducing crosstalk between detection channels. Alternatively, it can directly cycle through the detection channels sequentially.

[0049] The optical detection device can be implemented as a lidar. Further optionally, the lidar can be, for example, a mechanical lidar with a rotating mechanism. Alternatively, it could be a lidar without a rotating mechanism.

[0050] like Figures 1 to 3 The diagram illustrates the structure of a lidar that may be implemented using a photodetector in various embodiments of this application.

[0051] like Figure 1 The diagram shows a schematic representation of the structure of a lidar 10 in one embodiment.

[0052] In this example, the lidar 10 includes a transmitting module 11 and a photodetector module 12. The transmitting module 11 includes a light transmitter array 111, which comprises multiple light transmitters 1111. The photodetector module 12 includes a photodetector array 121, which comprises multiple photodetectors 1211. In a specific example, the light transmitting module 11 may further include a driving circuit for the light transmitter array 111; the photodetector module 12 may further include circuitry for processing the echo signal (e.g., an analog-to-digital converter). However, since only the signal transmission process of the transmitted and echo signals needs to be shown, it is not illustrated or described in detail here.

[0053] exist Figure 1In the diagram, each light emitter 1111 outputs a transmission signal, which is then emitted from the lidar 10 after passing through the transmitting lens 112 (e.g., shaping / collimating). When it encounters an obstacle A, the signal is reflected to form an echo signal. The echo signal enters the lidar 10 and is detected by the photodetectors 1211 in the photodetector array 121 after passing through the receiving lens 122 (e.g., shaping / converging). It can be understood that the diagram schematically shows one light emitter 1111 and one photodetector 1211 forming a detection channel; that is, the echo signal formed by the reflection of the transmission signal from one light emitter is detected by one photodetector 1211. If there are N pairs of light emitters 1111 and photodetectors 1211, N detection channels can be formed, each corresponding to a different field of view. Optionally, the fields of view between detection channels can overlap or not overlap.

[0054] Of course, this is just one example. In other embodiments, the number of light emitters 1111 and light detectors 1211 that make up the detection channel is not fixed, and at least one light emitter 1111 can form a detection channel with at least one light detector 1211. When the light emitter 1111 and light receiver belonging to a detection channel are activated respectively, the detection channel is in working state, thereby enabling the detection of obstacle A.

[0055] In some embodiments, each light emitter 1111 can be a laser, such as a vertical-cavity surface-emitting laser (VCSEL) or an edge-emitting laser (EEL). Correspondingly, each photodetector 1211 can be implemented, for example, an avalanche photodiode (APD) or a silicon photomultiplier (SiPM). The laser can be driven to emit light by applying a driving current; a bias voltage (V0) is applied to the photodetector 1211 implemented as an avalanche photodiode (APD) or silicon photomultiplier. bias ), to activate photodetector 1211 to detect light signals.

[0056] It should be noted that, Figure 1 The optical path shown is only a schematic representation and does not actually limit the optical path structure for transmitting signals and transmitting echo signals inside the optical detection device.

[0057] like Figure 2 The diagram shown illustrates the structure of a lidar in another embodiment of this application.

[0058] Figure 2 The diagram shows a portion of the internal structure of the lidar in a horizontal plane from a top-down perspective. For clarity, the housing of the photodetector is not shown. The horizontal plane can be a plane perpendicular to the height direction of the photodetector, and may be, for example, a horizontal plane or other planes.

[0059] The lidar includes: a viewing window 21, a light emitting end 22, a light detecting end 23, a rotating component 24, a redirecting component 25, a transmitting lens 26, and a receiving lens 27, etc. The lidar can be, for example, a forward-facing lidar, as shown in the figure, with the viewing window 21 facing forward for detection.

[0060] The optical transmitter 22 includes an optical transmitter array 221, wherein the optical transmitters are used to output transmitted signals; the optical receiver includes a photodetector array 231, wherein the photodetectors are used to detect the echo signals of the transmitted signals.

[0061] The light emitting end 22 transmits signals and receives echo signals through the window 21. Exemplarily, the window 21 can be a flat surface. In other embodiments, the window 21 can also be a curved surface.

[0062] The emitting lens 26 can be disposed at the front of the light emitting end 22 to collimate and transmit the emitted signal from the light emitting end 22. Exemplarily, the emitting lens 26 can be a lens group, or a plano-convex lens equivalent to the optical effect of a lens group, with its convex surface facing the light emitting end 22. The receiving lens 27 can be disposed at the front of the light detecting end 23 to converge the passing echo signal towards the light detecting end 23. Exemplarily, the receiving lens 27 can be a lens group, or a plano-convex lens equivalent to the optical effect of a lens group, with its flat surface facing the light detecting end 23.

[0063] The rotating component 24 rotates continuously and in a controlled manner. Figure 2 The example demonstrates a one-dimensional rotation in the horizontal plane (schematically shown as counter-clockwise in the diagram), enabling scanning of the horizontal field of view (relative to the vertical field of view). It is understood that while the example above shows vertical field-of-view scanning aligned with the height of the photodetector achieved by a column-oriented light emitter, and horizontal field-of-view scanning achieved by a one-dimensional rotation of the rotating component 24, this is not a limitation. In other specific examples, the placement angle of the photodetector can also be changed, for example, compared to... Figure 2 The light emitter rotates 90 degrees to achieve, for example, vertical field scanning by one-dimensional rotation of the rotating element 24, while horizontal field scanning is achieved by the light emitter changing from "column" to "row".

[0064] For example, the rotating member 24 can be sleeved around the motor shaft so that it rotates along with the motor shaft when the motor drives it to rotate. The rotating member 24 includes at least one reflective surface used by the optical path of the transmitted signal and the optical path of the echo signal. When there is only one reflective surface, the optical path of the transmitted signal and the optical path of the echo signal can share this reflective surface; while when there are multiple reflective surfaces, the optical path of the transmitted signal and the optical path of the echo signal can also share the same reflective surface of the rotating member 24, or the transmitted optical path and the received optical path can use different reflective surfaces of the rotating member 24. Figure 2 In the example, the rotating component 24 is exemplarily shown as a rectangular body, and its two opposing side surfaces 241 and 242 can be reflective surfaces. When the rotating component 24 rotates to a preset position, such as the position shown in the figure, one reflective surface 241 deflects the emitted signal onto the viewing window 21, and then the emitted signal passes through the viewing window 21 to the environment outside the photodetector for detection; if the emitted signal encounters an obstacle and forms an echo signal, the echo signal will pass through the viewing window 21 to the reflective surface 241, be deflected by the reflective surface 241, and then reach the photodetector along the optical path of the echo signal.

[0065] The redirector 25 is located in the optical path of the transmitted signal and the optical path of the echo signal, configured to output the transmitted signal to the rotating member 24, and has a passage for the echo signal to pass through. Redirection refers to changing the direction of the input optical signal and redetermining the transmission direction of the output optical signal through optical processing methods such as reflection, refraction, and transmission. Figure 2 In the example, the redirector 25 can be implemented as a reflector, which may have a reflective surface 251. In the optical path of the emitted signal, the reflective surface 251 is used to reflect the emitted signal from the light emitting end 22 onto the rotating member 24, while the rotating member 24 is located at, for example... Figure 2 When the signal is in the middle position, its reflective surface 251 may receive the transmitted signal and deflect it to the viewing window 21, and then emit it to the outside.

[0066] exist Figure 2 In the diagram, the passage portion is shown as gaps 28 located on both sides of the redirector 25. These gaps 28 can be formed between the redirector 25 and the inner wall of the housing of the light detection device, or between the redirector 25 and other parts (e.g., supports) disposed within the housing. Figure 2 In the example structure, in the optical path of the echo signal, the echo signal is reflected by a reflective surface 1 of the rotating member 24 and transmitted to the redirecting member 25, passing through the gap 28 on the side of the redirecting member 25 and being received by the photodetector 23.

[0067] exist Figure 2In this optical detection device, both the transmitted and echo signals pass through the optical path segment between the window 21 and the rotating component 24. This means the optical paths of the transmitted and echo signals overlap between the window 21 and the rotating component 24. This overlap can refer to coaxial optical paths, where the two optical path segments have coincident optical axes, as shown by M in the figure. It is understood that both the transmitted and echo signals pass through this overlapping optical path segment within the optical detection device. This coaxial optical path structure avoids the near-range blind zone problem caused by a side-axis optical path structure (where the optical paths of the transmitted and echo signals do not overlap at all). Furthermore, under the reflection of the reflective surface 251 of the redirector 25, the optical paths of the transmitted and echo signals also overlap (coaxially) in the optical path segment with optical axis N.

[0068] Specifically, the rotating component 24 can rotate continuously to transmit signals and receive echo signals at different times, or it can reciprocate to transmit signals and receive echo signals at different times. It is understood that the rotational speed of the rotating component 24, the number of reflective surfaces, and the switching speed of adjacent light emitters affect the frame rate of the lidar point cloud detection. These factors need to be coordinated to achieve a preset frame rate. When the detection frame rate is fixed, a larger number of reflective surfaces requires a smaller rotational speed. Therefore, the rotational speed and the number of reflective surfaces of the rotating component 24 can be set according to actual detection needs. The number of reflective surfaces is also related to the structure of the rotating component 24, and can be at least two, such as 2, 3, 4, or more. In a specific example, the rotating component 24 can be a prism. The cross-section of the rotating component 24 can be axisymmetric or centrosymmetric to achieve uniform time transmission and reception of light signals. For example, with... Figure 2 If the rotating component 24 is a prism with a rectangular cross-section, its two opposite surfaces can be reflective surfaces. Alternatively, if the rotating component 24 is a prism with a square cross-section, all four of its sides can be reflective surfaces.

[0069] like Figure 3 As shown, this demonstrates for Figure 2 A schematic diagram of the structure showing the shape change of the rotating component. Figure 3 In the example shown, the rotating component 34 is a prism with an equilateral triangular cross-section, and all three of its sides can be reflective surfaces. During rotation, the three reflective surfaces can be used in turn for optical signal transmission, and there are no sides not used for optical signal transmission. It should be noted that in other examples, the rotating component can also be implemented as a prism with a more polygonal cross-section, and is not limited to the examples mentioned above.

[0070] It is understandable that the above Figures 1 to 3This illustration merely demonstrates the structures of several lidar systems to help readers understand the possible application scenarios of the proposed solution, and is not intended to limit its application to the lidar systems listed above. The following section provides a detailed explanation of the solution for reducing crosstalk between detection channels.

[0071] To clearly illustrate the staggered structure between the light emitter rows, please refer to [link / reference needed]. Figure 4A and Figure 4B .

[0072] like Figure 4A The diagram shown illustrates the frontal arrangement of the light emitter array in one embodiment of this application.

[0073] A light emitter array 41 is disposed on a circuit board 42 (PCB). The light emitter array 41 may include N columns of light emitters that are staggered from each other. Each column of light emitters extends along a first direction, forming a scan of the field of view in the first direction, where N > 1. Exemplarily, the first field of view may be the vertical field of view of a photodetector. Optionally, the fields of view of adjacent light emitters in a column may not overlap with each other. Specifically, in a column of light emitters, each light emitter corresponds to a vertical field of view, so the combination of the vertical fields of view of each light emitter in a column corresponds to the vertical field of view of that column of light emitters (the field of view of a row of light emitters can be obtained similarly), and the combination of the vertical fields of view of each column of light emitters corresponds to the vertical field of view of the photodetector. The number of light emitters is determined by the vertical field of view of the photodetector and the vertical field of view of each light emitter.

[0074] Figure 4B Shown as Figure 4A A schematic diagram of the left-side partial structure is shown. The light emitter column on the left is not aligned with the adjacent light emitter column on the right in the column direction, forming the aforementioned misalignment. More specifically, the first light emitter b1 in the right-side light emitter column is slightly lower than a1, and slightly higher than the second light emitter a2 on the left. The absolute value of the vertical field of view corresponding to a1 > the absolute value of the vertical field of view corresponding to light emitter b1 > the absolute value of the vertical field of view corresponding to a2. For example, the vertical field of view of the lidar is +30° to -30° (with the horizontal direction as 0, upward tilt as positive, and downward tilt as negative). Assuming the vertical angular resolution of the lidar is 0.2°, the light emitted by a1 is shaped by the lens (group) and emitted towards -30°, i.e., a1 corresponds to a -30° vertical field of view; b1 corresponds to a -29.8° vertical field of view; and a2 corresponds to a -29.6° vertical field of view. The absolute values ​​of the vertical field of view angles of a1, b1, and a2 are 30° > 29.8° > 29.6°, respectively. The term "misalignment" can also be understood as each laser having at least a partial non-overlapping field of view in the first direction (e.g., the vertical direction).

[0075] from Figure 4BAs can be seen from the side, b1 fills the gap between a1 and a2 in the column direction, thus making the light emitters more densely distributed in the column direction, thereby improving the vertical resolution of the photodetector. For example... Figure 4A In the array of light emitters, the vertical fields of view of all the light emitters in the column direction (corresponding to the vertical field of view) hardly overlap, and after being stitched together, they form the vertical field of view of the light detection device. This arrangement can be considered as an arrangement in one dimension in the vertical direction (1D solid-state). Similarly, in other embodiments, adjacent rows of light emitters can also be arranged in an alternating manner in the row direction, which will not be elaborated here.

[0076] on the one hand, Figure 4A The linear array of light emitters 41 shown reduces the number of light emitters and lowers costs compared to arrays such as square arrays. On the other hand, the staggered structure between adjacent light emitter columns in the linear array results in a smaller size and higher resolution compared to aligned multi-column lasers.

[0077] As described in the previous embodiments, multiple detection channels are formed between the optical transmitter array 41 and the photodetector array. During the transmission and reception of an optical signal, multiple optical transmitters in the optical transmitter array 41 are activated to emit light, and multiple photodetectors in the photodetector array are activated to perform detection, thus constituting multiple detection channels. During this process, crosstalk may occur between the detection channels operating together.

[0078] To reduce crosstalk between detection channels, in some embodiments, each row or column of optical transmitters can be divided into multiple optical transmitter banks, each containing multiple optical transmitters corresponding to multiple detection channels. During a signal transmission, when the optical transmitter array 41 is operational, optical transmitters are selected from each optical transmitter bank to emit light, avoiding the simultaneous operation of several optical transmitters in the same bank. This ensures sufficient isolation space between optical transmitters of different detection channels activated during the same signal transmission, i.e., the space occupied by the inactive optical transmitters between two activated optical transmitters, thereby reducing crosstalk. Similarly, for a photodetector array, it can also be divided into multiple photodetector banks. During a signal transmission, photodetectors are selected from different photodetector banks for activation, also forming isolation space between photodetectors of different detection channels activated during the same signal transmission, thereby reducing crosstalk.

[0079] Optionally, the grouping of the optical transmitter array 41 and the individual selection of optical transmitters to activate during a signal transmission process, as well as the grouping of the photodetector array and the individual selection of optical transmitters to activate during a signal transmission process, can be implemented individually or concurrently. When implemented concurrently, crosstalk between multiple detection channels (especially adjacent detection channels) operating simultaneously during a single signal transmission process can be reduced more effectively.

[0080] The photodetector includes a control module (e.g., implemented using an FPGA, SoC, or other ASIC) that controls the emission of light from each emitter in the photodetector array. Those skilled in the art will understand that the aforementioned grouping of the photodetector array 41 actually involves the control module selecting and controlling a predetermined number of photodetectors to emit light simultaneously (also described herein as "together"), thereby eliminating overlap between the fields of view of the simultaneously emitting photodetectors. This ensures that there is no overlap between the fields of view of the simultaneously emitting photodetectors within the detection range of the photodetector.

[0081] In some embodiments, multiple optical emitters of the optical emitter group can be integrated onto at least one chip using semiconductor processes. For example, if the optical emitter is a laser, then the chip is a laser chip. By integrating multiple optical emitters onto a single chip, the problem of large spacing between optical emitters caused by packaging individual optical emitters can be avoided. This allows for the realization of highly integrated optical emitter arrays and corresponding optical emitter groups, which is beneficial for reducing the size of the optical detection device and increasing the line density of the lidar.

[0082] In other embodiments, the entire light-emitting section can be integrated onto a single chip using semiconductor technology. By grouping the light emitters through circuit connections and controlling the emission sequence, costs can be further reduced and processing efficiency improved.

[0083] To simplify the explanation, the following illustration only uses the division of the optical emitter array 41 into optical emitter groups as an example. Figure 4C As shown, the display is based on Figure 4A The example structure is shown in the schematic diagram illustrating the division of optical emitter groups. In this example, every 8 optical emitters arranged continuously in a column form a unit, and two units (16 optical emitters) in a column form an optical emitter group, resulting in a total of 8 optical emitter groups, namely Bank0 to Bank7. Figure 4D As shown, in the transmission and reception of an optical signal, one optical transmitter in each Bank can be activated, so that eight optical transmitters emit light simultaneously in one signal transmission process, which are represented by black blocks that are different from the other blocks in the figure.

[0084] As can be seen, by grouping the light emitters and selecting each emitter to emit light, the greater the number of light emitters in each group, the larger the isolation space between the activated light emitters.

[0085] It should be noted that, Figure 4C The way the optical emitters are divided is just an example and is not the only one. For example, a bank can be formed by a unit of 8 optical emitters arranged continuously in a column, or by 3 or more units in a column, or by a bank of optical emitters arranged discretely, such as in different rows or at different positions. It is not limited to the diagram shown.

[0086] For example, adjacent rows of light emitters or groups of light emitters in a column of light emitters can also be staggered in the extending direction. For instance, in the case of a Bank in the figure, adjacent columns of Banks are seen to be staggered in the column direction. This example is similar to the staggered arrangement of light emitters in adjacent columns or rows of light emitters in order to increase resolution.

[0087] In some examples, the signal transmission process for activating each light emitter in each light emitter group and / or each light detector in each light detector group differs; that is, only one light emitter in each light emitter group is activated during a single signal transmission, and / or only one light detector in each light detector group is activated during a single signal transmission. Specifically, in one signal transmission, a1 in Bank0 is activated, b1 in Bank1 is activated, and each of the other banks selects one light emitter to activate; in the next signal transmission, a2 in Bank0 is activated, b3 in Bank1 is activated, and so on, with each of the other banks selecting another light emitter to activate. This continues until all light emitters in each bank have been activated, and then they are activated in turn again. Thus, a1 and a2 will not emit light simultaneously during a single signal transmission, and the same applies to b1 and b3.

[0088] Similarly, the individual photodetectors in each photodetector group can be activated in turn during different signal transmission processes. For example, in photodetector group Bank9, photodetectors i2 and a1 form one detection channel, and i1 and a2 form another detection channel; in Bank10, j1 and b1 form one detection channel, and j2 and b2 form another. When a1 and b1 are activated during a signal transmission process, i2 and j1 are also activated, and so on.

[0089] like Figure 4CThe display shows 8 banks, each with 16 optical transmitters, for a total of 128 optical transmitters. If one optical transmitter and one photodetector form a detection channel, there are a total of 128 detection channels, or "128 lines". During each signal transmission, 8 of the 128 detection channels work together, and all detection channels are traversed after 16 signal transmissions. Each optical transmitter can be, for example, a VCSEL laser, achieving an extremely high vertical resolution of approximately 0.2° with a vertical field of view of 25° for the lidar.

[0090] like Figure 4A , Figure 4B , Figure 4C The illustrated light emitter array is a linear array. The number of light emitters in the column and row directions corresponds to the dimensions in those directions. The figure exemplifies that the column dimension of the light emitter array is significantly larger than the row dimension, meaning the column dimension is 3 to 5 times larger than the row dimension. Those skilled in the art will understand that, similarly, in other examples, the row dimension of the light emitter array may be significantly larger than the column dimension. In other words, when the light emitter array is a two-dimensional array, the dimensions in the two dimensions are significantly different, with a ratio greater than 3 or 5. The length of these dimensions corresponds to the number of light emitters and also affects the field of view and resolution in that dimension. The dimensions in different dimensions can be selected according to the requirements of the field of view and resolution. It is understood that the above-set dimension ratios apply not only to two-dimensional light emitter arrays but also to one-dimensional light emitter arrays. The difference is that the dimension ratio of a two-dimensional light emitter array may be N:M, while the dimension ratio of a one-dimensional light emitter array is N:1.

[0091] In specific applications, optical detection devices can be implemented as lidar applied to moving vehicles (such as cars). Typically, in the field of lidar, each detection yields a detection result (such as a point cloud map), which covers the entire horizontal and vertical field of view.

[0092] In scenarios such as road driving, obstacles might be people or vehicles on the road, which are crucial for autonomous driving. Among the various detection channels of a LiDAR system, the middle detection channel has a wider field of view covering people or vehicles on the road; the closer the detection channel is to the edge, the farther away it is from these obstacles. Understandably, the light emitters in the middle region of the light emitter array belong to the middle detection channel, while the light emitters in the edge region of the light emitter array belong to the edge detection channels.

[0093] To improve the effectiveness of near-range obstacle detection, in a single detection (e.g., detection corresponding to a horizontal field of view), in addition to distance detection (e.g., 150m), the lidar can emit additional light for near-range detection (e.g., 3m). The results of distance and near-range detection are combined to obtain the final detection result. In specific examples, the near-range and distance detection actions can be implemented through different flight time windows. The flight time window refers to a flight time range, calculated as t = 2 × d / c, where t is the flight time from the emission of the light transmitter to the receipt of the echo signal, d is the obstacle distance, c is the speed of light, and 2 × d represents the round-trip distance between the emitted signal and the echo signal. For example, when detecting an object at a distance of 150 meters, the system restricts the reception of echo signals to only those received within a preset flight time range within that 150-meter distance; echo signals outside or below this preset flight time range are excluded.

[0094] In one embodiment, the distances for distance measurement and proximity measurement are complementary; for example, the distance measurement distance is set at more than 3 meters, and the proximity measurement distance is set at less than 3 meters. In other embodiments, the distance measurement and proximity measurement distances may have a small overlap; for example, the distance measurement distance is set at more than 3 meters, and the proximity measurement distance is set at less than 5 meters, with a 2-meter overlap in detection distance.

[0095] In possible examples, the distance for distance measurement could be 100-150 meters, 150-200 meters, or 200-250 meters; the distance for proximity measurement could be 3-5 meters, 5-10 meters, etc. Because different light emitters emit lasers at different angles, the spacing between the different emitted laser beams increases at long distances. Therefore, for distance measurement, a denser array of light emitters is needed to maintain the point cloud density. For proximity measurement, the density and number of light emitters can be reduced accordingly.

[0096] In possible instances, detection channels can be used with partial or complete overlap between near-range and far-range detection actions. For example, the optical emitter in the middle region of the first direction of the optical emitter array can be used for both far-range and near-range detection at 250 meters and 3 meters, respectively. In cases where far-range detection is the primary focus and near-range detection is secondary, the frequency of actions and the resources of detection channels in each detection can be tilted towards far-range detection actions, such as performing one near-range detection action after every four far-range detection actions.

[0097] In possible examples, fewer light emitters are used for close-range measurements, and the corresponding number of detection channels is also reduced. For instance, to limit close-range measurements to channels near the center of eight banks, one could select, say, fewer than 128, such as 40 light emitters. If each emitter corresponds to one detection channel, this would constitute 40 detection channels, which would then sequentially poll for the close-range measurement. Optionally, the polling method for close-range and distance-range measurements can also differ. For example, during each distance-range measurement signal transmission, multiple banks in the central area (e.g., ...) might be polled. Figure 4D In the process of transmitting a signal from one of the multiple banks in the middle area, only one channel of one bank is selected to work.

[0098] In possible instances, the distance measurement action corresponds to various detection distances, such as 150 meters and 250 meters. The closer the activated light emitter is to the center of the light emitter array, the greater the expected detection distance, meaning a larger expected detection time window. For example, a light emitter located relatively close to the center in the vertical direction provides a 250-meter distance measurement time window (window t = 2 × d / c), with an expected maximum detection range of 250 meters; a light emitter at the relatively edge provides a 150-meter distance measurement time window, with an expected maximum detection range of 150 meters.

[0099] The above-described activation methods for light emitters are merely examples and do not limit their implementation possibilities. For instance, in other examples, multiple light emitters corresponding to a vertical field of view (e.g., on the same row) can be configured, but these multiple light emitting units do not emit light simultaneously (e.g., they emit light in a polling manner), which can increase their respective lifetimes and reliability.

[0100] In some embodiments, by configuring the driving mode of the optical emitter array and the corresponding driving circuit, each optical emitter can be controlled individually; thus, it is possible to select individual optical emitters to emit light in a polling manner, or to emit light together, or to emit light in any other combination. For example, the individual optical emitters in the optical emitter array can be polled in any order, at any interval, and according to signal characteristics (such as wavelength, pulse width, number of pulses, pulse peak value, and one or more combinations of inter-pulse time intervals), thereby achieving flexible electronic scanning.

[0101] In some examples, to reduce crosstalk between detection channels, the signal characteristics of the optical signals transmitted in different detection channels operating during the same signal transmission process are not entirely the same. Each detection channel transmits an optical signal including a transmitted signal and a corresponding echo signal. The optical detection device may also include a control module (e.g., implemented using an FPGA, SoC, or other ASIC) to determine the detection channel to which a signal belongs based on its signal characteristics.

[0102] Specifically, the photodetector converts the received optical signal into an electrical signal, which, after certain signal processing (such as filtering and analog-to-digital conversion), is transmitted to the control module. The control module can determine whether the signal characteristics of the echo signal match the signal characteristics of the emitted signal from the optical transmitter of the corresponding detection channel. If a match is found, the echo signal is used for the corresponding detection channel to calculate the detection result, such as calculating the distance to the target object. In specific examples, the control module can be implemented using, for example, a microcontroller unit (MCU), a programmable gate array (FPGA), or a system-on-a-chip (SoC).

[0103] In some examples, each optical transmitter is activated by a drive signal from a driving circuit, which may be generated by the driving circuit of the optical transmitter. Optionally, the drive signal may include one or more pulsed electrical signals (e.g., periodic pulse signals), and the emitted signal of the optical transmitter will correspondingly include one or more pulsed optical signals. In relevant examples, the dimensions of the signal characteristics may include one or more combinations of wavelength, pulse width, number of pulses, pulse peak value, and inter-pulse time interval.

[0104] Optionally, based on the example that optical transmitters within the same BANK may not emit light during the same signal transmission process, in order to simplify calculation considerations, the signal characteristics of each optical transmitter within the same BANK can be set to be the same, so that each BANK has its own exclusive and different signal characteristics.

[0105] The principles of signal characteristics in various dimensions are explained through examples.

[0106] In the example using wavelength as a signal characteristic, the wavelengths of the signals emitted by each group of optical transmitters are not exactly the same. Furthermore, the optical transmitters operating during the same signal transmission process emit signals with different wavelengths. For example, BANK0, BANK1, BANK2, and BANK3 each have one optical transmitter emitting a signal during the same signal transmission process. BANK0 is configured as multiple optical transmitters emitting optical signals with wavelength λ0, and BANK1 to BANK3 are respectively configured as optical transmitters emitting optical signals with wavelengths λ1 to λ3, where λ0 ≠ λ1 ≠ λ2 ≠ λ3. Thus, in each signal transmission process, an optical transmitter is selected from each of the four banks to emit an optical signal, and the wavelengths of the signals emitted by the four optical transmitters simultaneously emitting signals during any given signal transmission process are all different.

[0107] Furthermore, the photodetector array provides photodetector groups corresponding to the photoemitting group. Each photodetector in each photodetector group can be equipped with a filter unit upstream of its optical path. Each filter unit can be configured to allow only the echo signal of the wavelength corresponding to its own detection channel to pass through, thereby filtering out the echo signals of other detection channels and ambient light interference.

[0108] As another example, such as Figure 5A As shown, the optical transmitter array is divided into n groups of optical transmitters. Each group emits a signal with a different wavelength, λ1 to λn. Therefore, the optical transmitter array can simultaneously emit up to n signals. When any number of groups from the n groups are selected for activation, the multiple transmitters emit signal beams of different wavelengths. When all n groups are activated simultaneously, in a single transmission and reception of the optical signal, each group selects one transmitter to emit a signal for detection. The emitted signal beam is emitted through a transmitting lens and reflected by the target object to form an echo signal. The wavelength of each echo signal is the same as the corresponding incident emitted signal, also λ1 to λn. The n echo signals return to the photodetector through a window and are then transmitted to the photodetector array through a receiving lens. In a photodetector array, n photodetector groups can be provided corresponding to n light emitter groups. Each photodetector in each photodetector group can be equipped with a filter unit in front of each photodetector. Each filter unit can be configured to allow only the echo signal of the wavelength corresponding to its own detection channel to pass through. During the transmission of a single optical signal, one photodetector in a photodetector group is selected to be activated, so that the n echo signals can be detected by the n photodetectors respectively, without detecting echo signals of other wavelengths, thereby reducing interference.

[0109] In the example using pulse width as a signal characteristic, each transmitted signal can contain multiple pulses, and the ratio of these pulse widths can be configured differently, such as 2:3:1:..., to serve as the signal characteristic of this transmitted signal (which can be encoded to obtain signal characteristic encoding). During the same signal transmission process, the pulse width ratios of the transmitted signals from different detection channels operating simultaneously are different. As an example, this can be achieved by using different pulse width ratios for different banks, for example... Figure 5B As shown, the transmitted signals of each optical transmitter in BANK0 contain multiple continuous pulses with a pulse width ratio of 1:2:1:..., while the transmitted signals of each optical transmitter in BANK1 contain multiple pulses with a pulse width ratio of 1:2:3:...; the pulse width ratios of other BANKs are also different. Therefore, during the same signal transmission process, the pulse width ratios of the transmitted signals from optical transmitters selected from different BANKs are different, resulting in different pulse width ratios for the echo signals generated by each. By determining whether the pulse width ratio of the echo signal is the same as the pulse width ratio of the transmitted signal of this detection channel, it can be determined whether the echo signal belongs to this detection channel. When the pulse width ratio of the echo signal is different from the pulse width ratio of the transmitted signal of this detection channel, it is filtered out as interference. Thus, by using different pulse widths as signal characteristics, the echo signals from different detection channels can be distinguished.

[0110] In examples where inter-pulse time intervals are used as signal characteristics, the inter-pulse time interval ratios of the transmitted signals from different detection channels operating simultaneously differ during the same signal transmission process. For example, this can be achieved by varying the inter-pulse time interval ratios of the transmitted signals from different banks. Figure 5C As shown, the pulse time interval ratio of the multiple consecutive pulses in the transmitted signal of the optical transmitter in BANK0 is 2:3:1:..., and the pulse time interval ratio of the multiple consecutive pulses in the transmitted signal of the optical transmitter in BANK1 is 2:2:3... Therefore, the pulse time interval ratio of the generated echo signals is also different. By determining whether the pulse time interval ratio of the echo signal matches the pulse time interval ratio of the transmitted signal of this detection channel, the echo signal attribution of different detection channels can be distinguished.

[0111] In examples where pulse count is used as a signal characteristic, the transmitted signals of different detection channels operating simultaneously contain different numbers of pulses during the same signal transmission process. For instance, the transmitted signals of optical transmitters from different banks contain different numbers of pulses, resulting in different numbers of pulses in their respective echo signals. By determining whether the number of pulses in the echo signal matches the number of pulses in the transmitted signal of the same detection channel, the attribution of the echo signals from different detection channels can be distinguished.

[0112] In examples where pulse peak value (corresponding to the peak light intensity or the peak value converted to an electrical signal) is used as a signal characteristic, the peak intensity ratios of multiple pulses contained in the transmitted signals of different detection channels operating simultaneously differ during the same signal transmission process. As an example, this is achieved by using different pulse peak intensity ratios of multiple pulses contained in the transmitted signals of optical transmitters from different banks. For instance, the pulse peak intensity ratio of multiple pulses contained in the transmitted signal of the optical transmitter in bank 0 is X:Y:Z:..., while the pulse peak intensity ratio of one or more pulses contained in the transmitted signal of the optical transmitter in bank 1 is W:X:Y... Therefore, the pulse peak intensity ratios of the generated echo signals are also different. By determining whether the pulse peak intensity ratio of the echo signal is consistent with the pulse peak intensity ratio of the transmitted signal of the same detection channel, the attribution of the echo signals from different detection channels can be distinguished.

[0113] Alternatively, the above signal characteristics can be combined to generate signal characteristics of optical signals from different detection channels.

[0114] It should be noted that the above ratios, such as pulse width ratio, pulse time interval ratio, and pulse peak intensity ratio, are integer ratios for illustrative purposes only. In practical applications, the above ratios can be any values.

[0115] It is understandable that, in various embodiments of the detection channel, one or more embodiments can be distinguished by signal characteristics. The optical detection device can be a lidar, which can poll and freely select any laser or any combination of lasers (by addressing the lasers) to achieve high-degree-of-freedom detection scanning, thereby achieving at least multiple objectives.

[0116] On the one hand, it allows for the free selection of detection targets and areas. Specifically, when the optical detection device is a lidar, it can be mounted on, for example, a moving vehicle (such as an autonomous vehicle) and move with it to perform detection. If a specific target or area of ​​interest is identified based on the point cloud data of a certain scan, then when a scan is needed again, free addressing can be used to select to activate / scan only this specific target or area of ​​interest. This can be applied to implementations such as encrypted scanning of specific targets or areas of interest.

[0117] On the other hand, it can reduce crosstalk in the detection channel. Because the specific area to be emitted or scanned can be freely selected, detection can also be performed as... Figure 4D In this embodiment, lasers with the largest possible physical spacing are selected to emit light in the same signal transmission process, which greatly reduces crosstalk in the detection channel and achieves better signal-to-noise ratio and detection effect compared with current lidar products.

[0118] On the other hand, it can reduce the number of probes required to collect point cloud data, thereby reducing the overall power consumption of the optical detection device. Because with the technological trend of increasing wire bundle density, a larger wire bundle density corresponds to higher energy consumption, which can cause additional heat dissipation and reliability issues.

[0119] In the example above, each optical transmitter in the optical transmitter array can be activated by a drive control signal from the drive circuit. Exemplarily, the signal characteristics of the transmitted signal from each optical transmitter can be determined by the signal characteristics of the drive control signal.

[0120] like Figure 6 The diagram shown illustrates the circuit structure of the driving circuit for the optical emitter array in one embodiment of this application.

[0121] The driving circuit includes:

[0122] The corresponding driver modules for the light emitters of each detection channel; and

[0123] A multiplexer (MUX) includes: an input terminal and multiple output terminals; the input terminal is used to input a drive signal (Trigger) for controlling the drive module to activate the optical transmitter; the multiple output terminals are connected one-to-one with each drive module, so that they are selected to connect with the input terminal and output the drive signal.

[0124] In the diagram, the number of drive modules is exemplarily shown as 16 corresponding to detection channels 0-15, labeled as drive modules 0-15. The diagram exemplarily shows the structure of drive module 0; the other drive modules can have the same structure. The light emitters for the 16 detection channels are labeled LD0-LD15.

[0125] The drive module includes: NMOS transistor M1, PMOS transistor M2, resistor R1, high voltage diode D1, Zener diode D2, and energy storage capacitor C.

[0126] A power supply line is provided, connected to a supply voltage HVDD. A line control unit K (which can be implemented as a switch) is connected in series in the power supply line. The input terminal of the line control unit is connected to HVDD, and its output terminal outputs HVDD1. The output terminal of the line control unit K is connected to the positive terminals of R1 and D1, the negative terminal of D2, and the source terminal of M2, respectively. The other end of resistor R1 is connected to the drain terminal of M1, and the gate terminal of M1 is connected to one output terminal of a multiplexer MUX, which is controlled to be turned on or off by a trigger. D1, D2, and R1 are connected in parallel. The negative terminal of D1 and the positive terminal of D2 are connected to the drain terminal of M1 and the gate terminal of M2. The drain terminal of M2 is connected to one end of the light emitter, and the other end of the light emitter is grounded. One end of capacitor C is connected to the power supply line, and the other end is grounded.

[0127] Optionally, the source of M1 can be used to input control signals, such as 8-bit digital signals. The source of M1 can be connected to the output of a temporary digital-to-analog converter (IDAC). The control signal is input to the input of the IDAC to be converted into an analog voltage and applied to the source of M1. This control signal controls the high or low level of the corresponding analog voltage Vgs, thereby controlling the switching state of M1 and M2. Alternatively, the source of M1 can be directly connected to a low potential, such as ground.

[0128] In the non-operating state, the line control unit K is turned on, making HVDD1=HVDD, M1 is turned off, so HVDD acts on the gate of M2, and M2 is also turned off, and the light emitter LD0 does not emit light.

[0129] In operation, the Trigger selects probe channel 0 via a multiplexer, i.e., selects drive module 0. When the Trigger is high, the corresponding line control unit K disconnects the power supply to HVDD; if the source of M1 is low, the Trigger controls M1 to conduct, pulling down the gate voltage of M2 to turn it on. C begins to discharge to maintain HVDD1, and correspondingly, a drive current is generated at the drain of M2, flowing through the light emitter LD0, driving it to emit light.

[0130] When the working state switches back to the non-working state, C continues to charge, M1 and M2 are cut off, and the light emitter LD0 does not emit light.

[0131] In some examples, the charging speed of the capacitor is relatively slow compared to the switching of the optical emitter's operating state. To support multi-pulse emission of the optical emitter (driven by a multi-pulse trigger signal), a capacitor C with a large capacitance can be used, so that the capacitor only needs to release a small portion of its stored charge to drive the optical emitter each time it emits light. Thus, even if the capacitor cannot recharge its consumed charge within the interval Δt between two emission events, the remaining charge can still drive the laser to emit light again. Since the capacitor's discharge current decreases as its charge decreases, to avoid insufficient discharge current (laser drive current) due to insufficient remaining charge when emitting light again, the capacitance of capacitor C can be optionally set to achieve a preset number of discharges, such as the discharge amount required for one emission being less than 10% of the total stored charge of capacitor C.

[0132] Therefore, it can be seen that the multi-pulse signal of the drive signal Trigger can control the emitted signal of the optical transmitter to be in the corresponding multi-pulse signal form. That is, the signal characteristics of the Trigger are related to, for example, consistent with, the signal characteristics of the emitted signal. Furthermore, by setting different signal characteristics of the Triggers for different detection channels, it is possible to achieve different emitted signals for different detection channels. Since the emitted signal and the echo signal have consistent signal characteristics, it is possible to achieve different signal characteristics of optical signals in different detection channels. Thus, it is possible to identify the detection channel to which the echo signal belongs based on signal characteristics, thereby reducing crosstalk between detection channels.

[0133] Corresponding to the previous example where the number of pulses was used as a signal characteristic, for example... Figure 7 The example shown is a dual-pulse pattern. First, Trigger1 drives the optical emitter to generate a pulse signal pulse1; after an interval of Δt, Trigger2 drives the laser again to emit pulse2. The number of pulses emitted simultaneously from multiple channels can be different; that is, different channels of optical emitters are driven by different numbers of Trigger signals to emit different numbers of optical emission signals.

[0134] For the example in which the pulse time interval is used as the signal characteristic, please refer to... Figure 7 , Figures 8A to 8D .

[0135] The pulse time interval between the multiple pulse signals contained in the optical transmitter signal is determined by the time interval of the trigger signal. Therefore, different timing codes can be used for the trigger signals corresponding to multiple optical transmitters emitting light simultaneously. Figure 7 and Figures 8A to 8D The optical pulse time interval is obtained by example based on the time interval between the rising edges of adjacent trigger pulses. The corresponding time axis (not shown) is from right to left, representing the time from the past to the present.

[0136] The light emitters belonging to different detection channels all emit, for example Figure 7 Taking the double-pulse transmission signal as an example, the Δt of the transmission signals of different detection channels are different, so as to distinguish their echo signals.

[0137] Or, as Figures 8A to 8D The diagram illustrates the possible pulse coding forms of the drive signals Trigger for BANK1 to BANK4, corresponding to different detection channels. The diagram exemplifies that each detection channel's Trigger consists of three pulses.

[0138] Specifically, in Figure 8AIn the BANK1, the Trigger includes three pulse signals: Trigger30, Trigger20, and Trigger10. The pulse time interval between Trigger30 and Trigger20 is Δt20, and the pulse time interval between Trigger20 and Trigger10 is Δt10.

[0139] exist Figure 8B In the BANK2, the Trigger includes three pulse signals: Trigger31, Trigger21, and Trigger11. The pulse time interval between Trigger31 and Trigger21 is Δt21 = Δt20, and the pulse time interval between Trigger20 and Trigger10 is Δt11 ≠ Δt10.

[0140] exist Figure 8C In the BANK3, the Trigger includes three pulse signals: Trigger32, Trigger22, and Trigger12. The pulse time interval between Trigger32 and Trigger22 is Δt21≠Δt20, and the pulse time interval between Trigger22 and Trigger12 is Δt11=Δt10.

[0141] exist Figure 8D In the BANK4, the Trigger includes three pulse signals: Trigger33, Trigger23, and Trigger13. The pulse time interval between Trigger33 and Trigger23 is Δt23≠Δt20, and the pulse time interval between Trigger22 and Trigger12 is Δt13≠Δt10.

[0142] Therefore, it can be seen that the pulse time interval ratios of the optical emission signals of the four detection channels encoded into their respective multipulses are not completely the same. They may be different for each of the four channels, different for each of the four channels, different for one of the channels (Δt1 and Δt2), or different for both of the channels (Δt1 and Δt2).

[0143] Corresponding to the previous example where pulse width was used as a signal characteristic, the pulse width ratios of multiple pulse signals in the triggers of different detection channels can be different. The pulse width of the pulse signals included in the transmitted signal varies with the pulse width of the trigger signal; the pulse width of the trigger signal can be positively correlated with the pulse width of the transmitted signal. Therefore, by changing the pulse width of the trigger signal, the multiple pulses emitted by the laser can be pulse-width encoded, such as... Figure 9 As shown. Figure 9The diagram schematically shows the waveform of a trigger in a detection channel, where the pulse width ratios of the three pulse signals Trigger1, Trigger2, and Trigger3 can be set.

[0144] It should be noted that although echo signals may exhibit variations such as pulse width expansion, the pulse widths of multiple pulse signals in the echo signal reflected from the same target object should change proportionally. Therefore, the validity of an echo can be determined based on the pulse width ratio among multiple pulse signals in the echo signal.

[0145] Corresponding to the previous example where intensity coding is used as the signal feature, its principle is similar to pulse width coding. The optical transmitter emits multiple pulses with a certain intensity ratio. The signal intensity ratios of the multiple pulses emitted by multiple lasers that emit light at the same time are different. By judging the intensity ratio of the multiple pulses in the echo, it is determined whether it is a valid echo.

[0146] In addition, combinations can be made corresponding to the signal characteristics of different dimensions mentioned above. For example, some detection channels emit double pulses, some channels emit triple pulses, and the detection channels that emit double pulses perform timing coding, pulse width coding, intensity coding, etc. between the double pulses. The detection channels that emit triple pulses also perform timing coding, pulse width coding, intensity coding, etc. between the triple pulses, so that the combined signal characteristics corresponding to the multiple channels working together are different.

[0147] In addition, to further prevent crosstalk, in some embodiments, the control module in the optical detection device can also perform the "transmit signal transmission - echo signal reception" signal transmission process twice or more consecutively for the same detection channel, and compare the time of flight (TOF) values ​​calculated from multiple (e.g., two) measurements. If the TOF values ​​obtained from multiple measurements are consistent (they can be the same or the error is below a preset threshold), the detection result of the detection channel is determined to be valid; otherwise, it is determined that the detection channel is subject to crosstalk, and the detection result is discarded.

[0148] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A lidar, comprising: An array of optical emitters, comprising multiple rows of optical emitters; The optical transmitter is configured to output a transmission signal, with one column of optical transmitters extending along a first direction and multiple columns of optical transmitters interleaved in the first direction; A photodetector array includes multiple photodetectors; the photodetectors are configured to detect the echo signal reflected from the transmitted signal; wherein the light transmitter array and the photodetector array constitute multiple detection channels, each detection channel including at least one light transmitter and at least one photodetector. A rotating component is configured to rotate in a second direction, causing the lidar to scan in the second direction; During a single signal transmission process, from sending the transmitted signal to detecting the corresponding echo signal, multiple optical emitters in the optical emitter array are activated to emit light. The optical transmitter array includes multiple optical transmitter groups, with the optical transmitters in each group located in the same column. During a single signal transmission, multiple optical transmitters activated belong to different optical transmitter groups.

2. The lidar according to claim 1, characterized in that, The light emitter array is a two-dimensional array; the ratio between the dimensions of the two-dimensional array in the two dimensions is greater than 3 or greater than 5.

3. The lidar according to claim 1, characterized in that, During the signal transmission process, multiple photodetectors in the photodetector array are activated, and multiple detection channels in operation are formed between the multiple activated light transmitters in the light transmitter array and the multiple activated photodetectors in the photodetector array; the photodetector array includes multiple photodetector groups; each activated photodetector belongs to a different photodetector group.

4. The lidar according to claim 1, characterized in that, Each optical transmitter in an optical transmitter group and / or each photodetector in an optical detector group is polled and activated during multiple signal transmissions.

5. The lidar according to claim 1, characterized in that, A first isolation range exists between two optical transmitters in an optical transmitter group; and / or, a second isolation range is formed between activated optical transmitters in two adjacent optical transmitter groups during a single signal transmission.

6. The lidar according to claim 1, characterized in that, The optical transmitter group includes a predetermined number of optical transmitters, and the predetermined number of optical transmitters of the optical transmitter group are integrated on at least one chip.

7. The lidar according to claim 6, characterized in that, A predetermined number of optical emitters in the optical emitter group are coupled to at least one driving circuit, which is configured to activate the predetermined number of optical emitters.

8. The photodetector according to claim 7, characterized in that, The driving circuit includes an energy storage capacitor, and the driving circuit is configured to open a path between the energy storage capacitor and the light emitter to activate the light emitter.

9. The lidar according to claim 1, characterized in that, The photodetector array includes multiple staggered columns of photodetectors, with one column of photodetectors extending along the first direction.

10. The lidar according to claim 1, characterized in that, Also includes: The redirector is configured to redetermine the transmission direction of the output optical signal.

11. The lidar according to claim 10, characterized in that, The redirecting element has a reflective surface.

12. The lidar according to claim 11, characterized in that, The reflective surface is configured to reflect the transmitted signal to the rotating component.

13. A detection method for lidar, characterized in that, include: Activate multiple optical transmitters in the optical transmitter array to send transmission signals; Activate multiple photodetectors in the photodetector array; The optical transmitter array includes multiple rows of optical transmitters, which are configured to output transmission signals. One row of optical transmitters extends along a first direction, and the multiple rows of optical transmitters are staggered in the first direction. The multiple activated optical transmitters and the multiple activated photodetectors form multiple detection channels in operation. The activated multiple light emitters belong to different light emitter groups.

14. A lidar, comprising: An optical transmitter array is configured to output a transmission signal. The optical transmitter array includes a first column of optical transmitters and a second column of optical transmitters. The first column of optical transmitters and the second column of optical transmitters extend along a first direction. The first column of optical transmitters and the second column of optical transmitters are located at different positions in a second direction, which is perpendicular to the first direction. A photodetector array, comprising multiple photodetectors; the photodetectors are configured to detect echo signals; The optical emitter array comprises multiple optical emitter groups, each optical emitter group comprising a predetermined number of optical emitters, and the predetermined number of optical emitters are integrated onto at least one chip. The first column of optical transmitters includes a first optical transmitter group and a second optical transmitter group, and the second column of optical transmitters includes a third optical transmitter group and a fourth optical transmitter group. Along the first direction, the first optical transmitter group and the second optical transmitter group are arranged alternately with the third optical transmitter group and the fourth optical transmitter group.

15. The lidar according to claim 14, characterized in that, The ratio of the dimensions of the light emitter array in the first direction to those in the second direction is greater than 3.

16. The lidar according to claim 14, characterized in that, The light emitter includes a vertical cavity surface-emitting laser.

17. The lidar according to claim 14, characterized in that, Also includes: The rotating component is configured to rotate in a second direction, causing the transmitted signal to scan in the second direction.

18. The lidar according to claim 14, characterized in that, During a signal transmission process, multiple optical transmitters in the optical transmitter array are activated to emit light, and multiple photodetectors in the photodetector array are activated to receive the echo signal.

19. The lidar according to claim 18, characterized in that, The plurality of lasers have at least a partial non-overlapping field of view in the first direction.

20. The lidar according to claim 18, characterized in that, Also includes: A driving circuit is configured to activate the plurality of optical emitters, the driving circuit including an energy storage capacitor configured to discharge the plurality of optical emitters.

21. The lidar according to claim 20, characterized in that, The capacity of the energy storage capacitor is sufficient to meet the requirements of a preset number of discharges.

22. The lidar according to claim 14, characterized in that, Also includes: The window is used to transmit the transmitted signal to the environment outside the lidar, and the echo signal is used to reach the interior of the lidar. The window can be flat or curved.

23. The lidar according to claim 22, characterized in that, Also includes: A rotating component is configured to rotate in a second direction, causing the transmitted signal to scan in the second direction, wherein the optical path of the transmitted signal and the optical path of the echo signal overlap between the window and the rotating component.

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