Optical detection device and detection method

Abstract

The optical detection device and detection method include an optical transmitter array (111), an optical detector array (121), and a control module. The optical transmitter array (111) includes a plurality of optical transmitters (1111), and the optical transmitters (1111) are configured to output a transmission signal. The optical detector array (121) includes a plurality of optical detectors (1211), and the optical detectors (1211) are configured to detect an echo signal reflected after the transmission signal encounters an obstacle, where the optical transmitter array (111) and the optical detector array (121) form a plurality of detection channels, and each detection channel includes at least one optical transmitter (1111) and at least one optical detector (1211). During one signal transmission process from transmitting a transmission signal to detecting a corresponding echo signal, the control module selects a predetermined number of optical transmitters (1111) to emit light simultaneously, and the fields of view of the multiple optical transmitters (1111) that emit light simultaneously do not overlap within the detection distance, thereby effectively reducing crosstalk between detection channels.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This patent application claims priority to a Chinese patent application filed on April 30, 2021, bearing application number 202110489107.7, for the invention "Optical detection device and detection method," and also claims priority to a Chinese patent application filed on May 31, 2021, bearing application number 202110606696.2, for the invention "Optical detection device and detection method," all of which are incorporated herein by reference.

[0002] The present application relates to the technical field of optical ranging, and in particular to optical detection devices and detection methods. [Background technology]

[0003] Laser radar is a device that realizes external detection by emitting a laser and receiving an echo signal that returns when the laser reaches the surface of a target. Therefore, a laser radar comprises an optical transmitting module and an optical detecting module.

[0004] Currently, the optical transmission module of a laser radar includes a laser device array containing multiple laser devices, and the optical detection module accordingly includes an optical detector array containing multiple optical detectors. At least one laser device and at least one optical detector form a detection channel, and each detection channel corresponds to a field of view (FOV), also known as a viewing angle. Usually, the number of lines in a so-called multi-line laser radar corresponds to the number of detection channels.

[0005] However, due to the requirement for system miniaturization, the layout space for the laser device array and the optical detector array is very limited, and the layout of the laser device and the optical detector must be compact. When a laser radar scans, if each laser device and each optical detector operate in parallel, crosstalk is likely to occur between the detection channels. For example, a detection channel A receives an echo signal of a detection point C obtained within the field of view of detection channel B, but the detection point C may be outside the field of view of detection channel A. As a result, C may appear in a position where it does not actually exist in the detection result (e.g., in a point cloud map). This situation is called a "ghost" phenomenon.

[0006] However, in laser radar applications such as autonomous driving, high-frequency and high-speed detection is required, so even if time-division emission and detection are controlled to some extent, it remains difficult to effectively reduce the effects of crosstalk.

[0007] In particular, for high-beam laser radars, such as laser radars with 32 lines or more (e.g., 32 lines, 64 lines, 128 lines, 256 lines, or more), which are the mainstream product development trend in the industry, the crosstalk problem is a major obstacle to the development of such products. Summary of the Invention

[0008] In view of the above-mentioned deficiencies of the prior art, the present application provides an optical detection device and detection method that solves the problems of the prior art.

[0009] In order to achieve the above and other related goals, a first aspect of the present application provides an optical detection device including: an optical transmitter array including a plurality of optical transmitters configured to output a transmission signal; an optical detector array including a plurality of optical detectors configured to detect an echo signal reflected after the transmission signal encounters an obstacle, wherein the optical transmitter array and the optical detector array form a plurality of detection channels, each detection channel including at least one optical transmitter and at least one optical detector; and a control module that selects and causes a predetermined plurality of optical transmitters to emit light simultaneously during a single signal transmission process from transmitting a transmission signal to detecting a corresponding echo signal, wherein the field of view of the plurality of optical transmitters that emit light simultaneously does not overlap within the detection distance.

[0010] In some embodiments of the first aspect, the optical transmitter array is a one-dimensional array or a two-dimensional array, and when the optical transmitter array is a two-dimensional array, the ratio of the dimensions in the two dimensions is greater than 3 or greater than 5.

[0011] In some embodiments of the first aspect, a plurality of activated optical transmitters in the optical transmitter array form a plurality of active detection channels with a plurality of activated optical detectors in the optical detector array, the optical transmitter array includes a plurality of optical transmitter groups, and / or the optical detector array includes a plurality of optical detector groups, and each of the activated optical transmitters belongs to a different optical transmitter group, and / or each of the activated optical detectors belongs to a different optical detector group.

[0012] In some embodiments of the first aspect, each optical transmitter in each optical transmitter group and / or each optical detector in each optical detector group is activated in turn over multiple signal transmission processes.

[0013] In some embodiments of the first aspect, there is a first separation range between two optical transmitters in the same optical transmitter group, and / or a second separation range is formed between activated optical detectors in two adjacent optical detector groups during the same signal transmission process.

[0014] In some embodiments of the first aspect, each optical transmitter group includes a predetermined number of optical transmitters, and a plurality of optical transmitters of the optical transmitter group are integrated on at least one chip.

[0015] In some embodiments of the first aspect, a plurality of optical transmitters of the optical transmitter group are coupled to at least one selection unit, the selection unit performing selection of the optical transmitters in response to an external signal.

[0016] In some embodiments of the first aspect, the optical transmitter array includes N rows of optical transmitters offset from one another, each row of optical transmitters extending along a first direction, and N>1; and / or the optical detector array includes M rows of optical detectors offset from one another, each row of optical detectors extending along the first direction, and M>1.

[0017] In some embodiments of the first aspect, the signal characteristics of the optical signals transmitted through each detection channel during the same signal transmission process are not completely the same.

[0018] In some embodiments of the first aspect, the optical detection device includes a control module that determines whether the signal characteristics of the echo signal detected by the optical detector match the signal characteristics of the transmitted signal from the optical transmitter of the corresponding detection channel, and if so, uses the echo signal in the corresponding detection channel to calculate the distance to the target.

[0019] In some embodiments of the first aspect, the transmission signal transmitted by the optical transmitter includes one or more pulse signals, and the signal characteristic dimensions include one or more combinations of wavelength, pulse width, number of pulses, pulse peak, and time interval between pulses.

[0020] 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 ratio of pulse widths between multiple pulses.

[0021] In some embodiments of the first aspect, the signal characteristics in the signal intensity dimension include determining whether the signal characteristics of the echo signal match the signal characteristics of the transmitted signal based on an intensity ratio between multiple pulses.

[0022] In some embodiments of the first aspect, the wavelengths of the transmitted signals from the optical transmitters in different detection channels operating in the same signal transmission process are different, and an optical filter unit is provided in front of the optical detector of each operating different detection channel to pass only the echo signal of the wavelength corresponding to that detection channel.

[0023] In some embodiments of the first aspect, the control module controls the optical transmitter array and the optical receiver array to continuously detect one detection channel multiple times during one signal transmission process to obtain time-of-flight values, and compares the time-of-flight values ​​detected multiple times. If the comparison results are consistent, it determines that the detection result of the channel is valid; otherwise, it discards the detection result.

[0024] In some embodiments of the first aspect, the light detection device includes a laser radar.

[0025] To achieve the above and other related goals, a second aspect of the present application provides a method for optical detection using an optical detection device described in any one of the first aspect, comprising the steps of activating a plurality of optical transmitters in the optical transmitter array to transmit a transmission signal, and activating a plurality of optical detectors in the optical detector array, wherein the activated plurality of optical transmitters form a plurality of detection channels in an active state with a plurality of activated optical detectors, each of which belongs to a different optical transmitter group and / or each of which belongs to a different optical detector group.

[0026]

[0003] In accordance with the above, in the optical detection device and detection method provided herein, multiple detection channels are configured between the optical transmitter array and the optical detector array in the optical detection device, and each detection channel includes at least one optical transmitter and at least one optical detector. In one embodiment, one detection channel may be configured with one optical transmitter and one optical detector. In another embodiment, one detection channel may be configured with one optical transmitter and multiple optical detectors. Multiple types of detection channel configurations may also be used in the same embodiment. During a single signal transmission process from transmitting a transmission signal to detecting a corresponding echo signal, multiple predetermined optical transmitters are selected to emit light simultaneously, and the fields of view of the multiple simultaneously emitting optical transmitters do not overlap within the detection distance. This provides sufficient spatial separation between simultaneously operating detection channels, effectively reducing crosstalk. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a structural schematic diagram of a laser radar that can be realized by the optical detection device in several embodiments of the present application; [Figure 2] 1 is a structural schematic diagram of a laser radar that can be realized by the optical detection device in several embodiments of the present application; [Figure 3] 1 is a structural schematic diagram of a laser radar that can be realized by the optical detection device in several embodiments of the present application; [Figure 4A] 1 is a front view of an arrangement structure of an optical transmitter array according to an embodiment of the present application; [Figure 4B] FIG. 4B is a schematic left side view of a portion of the structure of FIG. 4A. [Figure 4C] FIG. 4B is a structural schematic diagram of optical transmitter grouping based on the exemplary structure of FIG. 4A. [Figure 4D] FIG. 4D is a schematic diagram showing that each group of optical transmitters divided according to FIG. 4C emits light in multiple detection channels once. [Figure 5A] 1 is a schematic diagram illustrating the principle of detection using wavelength as a signal feature in an embodiment of the present application; [Figure 5B] FIG. 2 is a schematic diagram of a waveform in which the pulse width is a signal feature in an embodiment of the present application. [Figure 5C] FIG. 2 is a schematic diagram of a waveform in which the time interval between pulses is a signal feature in one embodiment of the present application. [Figure 6] FIG. 2 is a circuit structure diagram of a driving circuit for an optical transmitter array in an embodiment of the present application; [Figure 7] FIG. 10 is a schematic diagram showing the waveform of a trigger signal of a driving circuit in which the number of pulses is a signal characteristic in an embodiment of the present application. [Figure 8A] 1A and 1B are schematic diagrams of different waveforms of trigger signals of different optical transmitter groups with pulse time intervals as signal features in one embodiment of the present application; [Figure 8B] 1A and 1B are schematic diagrams of different waveforms of trigger signals of different optical transmitter groups with pulse time intervals as signal features in one embodiment of the present application; [Figure 8C] 1A and 1B are schematic diagrams of different waveforms of trigger signals of different optical transmitter groups with pulse time intervals as signal features in one embodiment of the present application; [Figure 8D] 1A and 1B are schematic diagrams of different waveforms of trigger signals of different optical transmitter groups with pulse time intervals as signal features in one embodiment of the present application; [Figure 9] 1 is a schematic diagram of the waveform of a trigger signal of one detection channel with pulse width as a signal characteristic in one embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0028] In the following, embodiments of the present application will be described using specific examples, but those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application may be implemented or applied in further different specific embodiments, and various modifications or changes may be made to each detail of the specification based on different perspectives and applications without departing from the spirit of the present application. It should be noted that, where not inconsistent, the examples and features in the examples in the present application can be combined with each other.

[0029] The present application may be embodied in various different forms and is not limited to the embodiments described herein.

[0030] For clarity in describing this application, parts that are not relevant to the description will be omitted, and the same or similar components will be labeled with the same reference numerals throughout the specification.

[0031] Throughout this specification, when a component is described as being "connected" to another component, it includes not only the case where the component is "directly connected" but also the case where the component is "indirectly connected" through an intervening element. Furthermore, when a component is described as "comprising" a certain component, it does not mean that the component excludes other components, but that the component may further include other components, unless otherwise specified.

[0032] When a component is described as being "on" another component, it may be directly on top of the other component, but there may be other components between them. Conversely, when a component is described as being "directly on" another component, it means that there are no other components between them.

[0033] In some instances, terms such as "first," "second," etc. are used herein to describe various elements, but these elements should not be limited by these terms. These terms are merely used to distinguish one element from another. Examples include descriptions such as "first interface" and "second interface." It should be noted that, as used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context dictates otherwise. It should be further understood that the terms "including" and "including" specify the presence of stated features, steps, operations, elements, components, items, types, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, types, and / or groups. The terms "or" and "and / or," as used herein, are intended to be inclusive or mean any one or any combination. 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, or A, B, and C." Exceptions to this definition can occur only when combinations of elements, features, steps, or operations are in some way inherently mutually exclusive.

[0034] The terminology used herein describes particular embodiments only and is not intended to limit the present application. As used herein, the singular forms "a," "an," and "the" include the plural forms unless the phrase clearly indicates otherwise. The term "comprising" as used in the specification is intended to embody certain properties, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other properties, regions, integers, steps, operations, elements, and / or components.

[0035] Relative spatial terms, such as "below," "above," and the like, may be used to more easily describe the relationship of one part shown in the figures to another part. Such terms include other orientations or operations of the device in use in addition to the orientation shown in the figures. For example, if the device in the figures were turned over, parts described as being "below" other parts would also be described as being "above" other parts. Thus, the exemplary term "below" includes both above and below. The device may be rotated 90 degrees or at other angles, and the relative spatial terms would be interpreted accordingly.

[0036] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. Terms defined in commonly used dictionaries are additionally interpreted as having a meaning consistent with the relevant technical literature and the contents of this disclosure, but should not be interpreted in an ideal or very formal sense unless defined.

[0037] As mentioned above, due to the increasing degree of miniaturization of optical transmitter arrays and optical detector arrays, multi-beam laser radars that use them for detection operations are prone to crosstalk between detection channels during detection. Although crosstalk can be reduced using a time-division activation method, due to the requirements of high-beam (more than 32 lines) laser radars, the switching time between detection channels is too short, making it difficult to effectively reduce crosstalk.

[0038] In view of this, the present application provides the following optical detection device, which includes an optical transmitter array and an optical receiver array, and can simultaneously activate optical transmitters and / or optical detectors that are widely spaced in the array, effectively reducing crosstalk between detection channels, and can directly and sequentially cycle through the detection channels.

[0039] The optical detection device may be realized as a laser radar. Optionally, the laser radar may be, for example, a mechanical laser radar having a rotation mechanism, or may be a laser radar without a rotation mechanism.

[0040] 1 to 3 are structural schematic diagrams of a laser radar that can be realized as a light detection device in several embodiments of the present application.

[0041] FIG. 1 is a structural schematic diagram of a laser radar 10 according to an embodiment.

[0042] In this example, the laser radar 10 includes a transmitting module 11 and an optical detection module 12. Here, the transmitting module 11 includes an optical transmitter array 111, which includes a plurality of optical transmitters 1111. The detection module 12 includes an optical detector array 121, which includes a plurality of optical detectors 1211. In a specific example, the optical transmitting module 11 may further include a drive circuit for the optical transmitter array 111, and the optical detection module 12 may further include a circuit for processing echo signals (e.g., an analog-to-digital converter, etc.); however, illustration and description thereof will be omitted here as it is only necessary to show the signal transmission process of the transmission signal and the echo signal.

[0043] 1, each optical transmitter 1111 outputs a transmission signal, which passes through the transmitting lens 112 (e.g., shaped / collimated) before being emitted from the laser radar 10. When it encounters an obstacle A, it is reflected to form an echo signal. The echo signal enters the laser radar 10, passes through the receiving lens 122 (e.g., shaped / focused), and is then detected by each optical detector 1211 in the optical detector array 121. In the illustration, one optical transmitter 1111 and one optical detector 1211 are schematically shown to constitute one detection channel. That is, the echo signal generated by the reflection of the transmission signal from one optical transmitter is detected by one optical detector 1211. It can be understood that if there are N pairs of optical transmitters 1111 and optical detectors 1211, N corresponding detection channels can be formed, and each detection channel can correspond to a different field of view. Optionally, the fields of view between the detection channels may or may not overlap.

[0044] Of course, this is just one example, and in other embodiments, the number of optical transmitters 1111 and optical detectors 1211 that make up a detection channel may vary, and at least one optical transmitter 1111 may form a detection channel with at least one optical detector 1211. When the optical transmitter 1111 and the optical receiver that belong to one detection channel are activated and operating, the detection channel is in an active state, and detection of obstacle A can be realized.

[0045] In some embodiments, each optical transmitter 1111 may be a laser device such as a Vertical Cavity Surface Emitting Laser (VCSEL) or an Edge Emitting Laser (EEL). Correspondingly, each photodetector 1211 may be realized by, for example, an avalanche photodiode (APD) or a silicon photomultiplier (SiPM). Here, the laser device can be driven to emit light by applying a driving current to the laser device, and a bias voltage (V bias ) activates the photodetector 1211 to detect the optical signal.

[0046] It should be noted that the optical path shown in FIG. 1 is merely a schematic representation, and is not limited to the optical path structure of the transmission signal and the optical path structure of the echo signal transmission within the optical detection device.

[0047] FIG. 2 shows a structural schematic diagram of a laser radar in another embodiment of the present application.

[0048] 2 shows a plan view of a portion of the internal structure of a laser radar in a lateral plane. For clarity, the housing of the optical detection device is not shown in the figure. The lateral plane may be a plane perpendicular to the height direction of the optical detection device, for example, a horizontal plane or other plane.

[0049] The laser radar includes a window 21, an optical transmitting end 22, an optical detecting end 23, a rotating member 24, a redirecting member 25, a transmitting lens 26, and a receiving lens 27. The laser radar may be, for example, a forward-facing laser radar, and as shown in the schematic arrangement in the figure, the window 21 is detecting toward the front.

[0050] The optical transmitting end 22 includes an optical transmitter array 221, in which the optical transmitters are used to output transmission signals, and the optical receiving end includes an optical detector array 231, in which the optical detectors are used to detect echo signals of the transmission signals.

[0051] The optical transmitting end 22 transmits a transmission signal and receives an echo signal through the window 21. For example, the window 21 may be a flat window. In other embodiments, the window 21 may have a curved structure.

[0052] The transmitting lens 26 may be provided in front of the optical transmitting end 22 to collimate the transmission signal of the optical transmitting end 22 before transmitting it. Exemplarily, the transmitting lens 26 may be a lens group or a plano-convex lens equivalent to the optical effect of a lens group, with its convex surface facing the optical transmitting end 22. The receiving lens 27 may be provided in front of the optical detecting end 23 to focus the passed echo signal to the optical detecting end 23. Exemplarily, the receiving lens 27 may be a lens group or a plano-convex lens equivalent to the optical effect of a lens group, with its flat surface facing the optical detecting end 23.

[0053] The rotating member 24 rotates continuously under control, and in the example of FIG. 2, this is shown as one-dimensional rotation in a horizontal plane (counterclockwise, as indicated by the arrow in the figure), thereby enabling scanning of a horizontal field of view (relative to the vertical field of view). In the above example, vertical field scanning is achieved by optical transmitters arranged in a column, which corresponds to the height direction of the optical detection device, and horizontal field scanning is achieved by one-dimensional rotation of the rotating member 24 in the horizontal direction, but it can be understood that this is not limited to this. In other specific examples, the arrangement angle of the optical detection device may be changed, for example, by rotating the rotating member 24 90 degrees compared to FIG. 2 to achieve vertical field scanning by one-dimensional rotation and horizontal field scanning by optical transmitters changed from "columns" to "rows."

[0054] For example, the rotating member 24 may be fitted onto the rotating shaft of a motor, so that it can rotate along with the rotating shaft when the motor drives the rotating shaft 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. If 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. If there are multiple reflective surfaces, the optical path of the transmitted signal and the optical path of the echo signal may share the same reflective surface of the rotating member 24, or the optical path of the transmitted signal and the optical path of the received signal may use different reflective surfaces of the rotating member 24. In the example of FIG. 2, the rotating member 24 is illustratively shown as a rectangle, and its two opposing vertical surfaces 241 and 242 may be reflective surfaces. When the rotating member 24 rotates to a predetermined position, for example, the position shown in the figure, one reflective surface 241 deflects the transmitted signal toward the window 21, and the transmitted signal passes through the window 21 and is emitted into the environment outside the optical detection device for detection. When the transmitted signal encounters an obstacle and an echo signal is formed, the echo signal passes through the window 21 and reaches the reflecting surface 241, and after being deflected by the reflecting surface 241, reaches the optical detector along the optical path of the echo signal.

[0055] The redirecting member 25 is located in the optical path of the transmission signal and the optical path of the echo signal, and is configured to form a passage for outputting the transmission signal to the rotating member 24 and for passing the echo signal. The redirection refers to a method of processing the optical signal by optical reflection, refraction, transmission, etc., which can change the direction of the input optical signal and re-determine the transmission direction of the output optical signal. In the example of FIG. 2, the redirecting member 25 may be realized as a reflector which may have one reflecting surface 251. In the optical path of the transmission signal, the reflecting surface 251 is used to reflect the transmission signal emitted from the optical transmitting end 22 to the rotating member 24. When the rotating member 24 is in the position shown in FIG. 2, the reflecting surface 251 can receive the transmission signal, deflect it to the window 21, and then emit it to the outside.

[0056] 2, the passing portions are shown as gaps 28 on the two near sides of the redirecting member 25, and the gaps 28 may be formed between the redirecting member 25 and the inner wall of the housing of the optical detection device or between another part (e.g., a bracket, etc.) provided in the housing. In the example structure of FIG. 2, in the optical path of the echo signal, the echo signal is reflected by one reflective surface 1 of the rotating member 24 and transmitted to the redirecting member 25, passes through the gaps 28 on the near sides of the redirecting member 25, and is received by the optical detection end 23.

[0057] In FIG. 2, both the transmitted signal and the echo signal pass through the optical path portion between the window 21 and the rotating member 24, i.e., the optical paths of the transmitted signal and the echo signal overlap between the window 21 and the rotating member 24. The overlapping may refer to the optical paths being coaxial, i.e., the two optical path portions have overlapping optical axes, as indicated by M in the figure. It can be seen that both the transmitted signal and the echo signal pass through overlapping optical path portions within this optical detection device, and this coaxial optical path structure can avoid the short-distance blind spot problem caused by a paraxial optical path structure (where the optical path of the transmitted signal and the optical path of the echo signal do not overlap at all). Furthermore, under the reflective effect of the reflecting surface 251 of the redirecting member 25, the optical paths of the transmitted signal and the echo signal also overlap (are coaxial) at the optical path portion N.

[0058] Specifically, the rotating member 24 can continuously rotate to transmit and receive echo signals at different times, or it can reciprocate to transmit and receive echo signals at different times. The number of rotations of the rotating member 24, the number of reflective surfaces, and the light-emitting switching speed of adjacent optical transmitters can affect the frame rate of laser radar point cloud detection. It is understood that cooperation of these elements is required to achieve a predetermined frame rate. For a given detection frame rate, the greater the number of reflective surfaces, the smaller the required number of rotations. As can be seen, the number of rotations and the number of reflective surfaces of the rotating member 24 can be set according to actual detection requirements. The number of reflective surfaces is also related to the structure of the rotating member 24 and may be at least two, for example, two, three, four, or more. In a specific example, the rotating member 24 may be a prism. The cross-section of the rotating member 24 may be axially symmetrical or centrosymmetrical to achieve uniform time transmission and reception of optical signals. For example, if the rotating member 24 in Fig. 2 is a prism with a rectangular cross section, two opposing surfaces can be used as reflective surfaces. Alternatively, if the rotating member 24 is a prism with a square cross section, all four side surfaces can be used as reflective surfaces.

[0059] Figure 3 shows a schematic diagram of a structure in which the shape of the rotating member in Figure 2 has been changed. In Figure 3, the rotating member 34 shown is a prism with a cross section of an equilateral triangle, and all three of its sides can be reflective surfaces. During rotation, the three reflective surfaces can be used alternately and continuously to transmit optical signals, and no side is unused for transmitting optical signals. It should be noted that in other examples, the rotating member may be realized as a prism with a more polygonal cross section, and is not limited to the above example.

[0060] It should be understood that Figures 1 to 3 merely show the structures of several types of laser radars to help readers understand the possible application scenarios of the solution of the present application, and are not limited to the laser radars listed above. The solution of the present application for reducing crosstalk between detection channels will be described in detail below.

[0061] For a clearer explanation of the offset structure between the rows of optical transmitters, please refer to Figures 4A and 4B together.

[0062] FIG. 4A is a schematic front view of the arrangement structure of an optical transmitter array in one embodiment of the present application.

[0063] The optical transmitter array 41 is mounted on a circuit board (PCB) 42. The optical transmitter array 41 may include N rows of optical transmitters offset from one another, each extending along a first direction and scanning a field of view in the first direction, where N>1. Exemplarily, the field of view in the first direction may be the vertical field of view of the optical detection device. Optionally, the fields of view of adjacent optical transmitters in a row may not overlap. Specifically, each optical transmitter in a row of optical transmitters corresponds to a vertical field of view, so that the combination of the vertical field of view of each optical transmitter in a row corresponds to the vertical field of view of the optical transmitter row (the field of view of the optical transmitter row can be obtained similarly), and the combination of the vertical field of view of each optical transmitter row corresponds to the vertical field of view of the optical detection device. The number of optical transmitters is determined by the vertical field of view of the optical detector and the vertical field of view of each optical transmitter.

[0064] Figure 4B shows a schematic left-side view of a portion of the structure shown in Figure 4A. The left-hand optical transmitter column and the adjacent right-hand optical transmitter column are not aligned in the column direction, forming the offset described above. More specifically, the first optical transmitter b1 in the right-hand optical transmitter column is slightly lower than a1 and slightly higher than the second left-hand optical transmitter a2. Here, the absolute value of the vertical field of view corresponding to a1 > the absolute value of the vertical field of view corresponding to optical transmitter b1 > the absolute value of the vertical field of view corresponding to a2. For example, the vertical field of view of a laser radar is +30° to -30° (horizontal is 0, upward diagonal is a positive value, and downward diagonal is a negative value). The vertical angular resolution of the laser radar is 0.2°. The light transmitted by a1 is shaped by the lens(es) and then transmitted to -30°. That is, a1 corresponds to a vertical field of view of -30°, b1 corresponds to a vertical field of view of -29.8°, and a2 corresponds to a vertical field of view of -29.6°. The absolute values ​​of the vertical field angles of a1, b1, and a2 are 30°>29.8°>29.6°, respectively. By offset, it may be understood that the fields of view of the lasers do not overlap at least partially in a first direction (e.g., vertical direction).

[0065] As can be seen from Figure 4B, when viewed from the side, b1 fills the gap between a1 and a2 in the column direction, thereby providing a denser distribution of the optical transmitters in the column direction and improving the vertical resolution of the optical detection device. For example, in the optical transmitter array of Figure 4A, the vertical fields of view of all the optical transmitters in the column direction (corresponding to the vertical field of view) barely overlap, and after being stitched together, they constitute the vertical field of view of the optical detection device. Such an array may be considered a one-dimensional array (1D solid-state) in the vertical direction. Similarly, in other embodiments, adjacent rows of optical transmitters may be alternately arranged in the row direction, which will not be described here.

[0066] On the one hand, the optical transmitter array 41 arranged in a linear array as shown in Fig. 4A reduces the number of optical transmitters and reduces costs compared to, for example, a square array, etc. On the other hand, the structure in which adjacent optical transmitter rows are staggered in a linear array has smaller dimensions and achieves higher resolution compared to aligned multiple rows of lasers.

[0067] As described in the previous embodiment, multiple detection channels are formed between the optical transmitter array 41 and the optical detector array, and in one optical signal transmission and reception, multiple optical transmitters in the optical transmitter array 41 are activated to emit light, and multiple optical detectors in the optical detector array are activated to perform detection, thereby forming multiple detection channels. In this process, crosstalk may occur between the detection channels that operate together.

[0068] To reduce crosstalk between detection channels, in some embodiments, each optical transmitter row or column can be divided into multiple optical transmitter banks, each containing multiple optical transmitters and corresponding to multiple detection channels. During a single signal transmission, when the optical transmitter array 41 is activated, a separate optical transmitter from each optical transmitter bank is selected to emit light, preventing multiple optical transmitters in the same bank from simultaneously activating. This ensures sufficient separation between activated optical transmitters of different detection channels during a single signal transmission, i.e., the space occupied by each inactivated optical transmitter between two activated optical transmitters, thereby reducing crosstalk. Similarly, the optical detector array can be divided into multiple optical detector banks, and each optical detector from each different optical detector bank can be selected and activated during a single signal transmission. Similarly, separation between activated optical detectors of different detection channels during a single signal transmission can be achieved, thereby reducing crosstalk.

[0069] Alternatively, either one of the grouping of the optical transmitter array 41 and the selection of each optical transmitter to be activated in a single signal transmission process and the grouping of the optical detector array and the selection of each optical detector to be activated in a signal transmission process may be selected, or both may be performed. Implementing both can more effectively reduce crosstalk between multiple detection channels (especially adjacent detection channels) that operate together in a single signal transmission process.

[0070] The light detection device includes a control module (e.g., an FPGA, SoC, or other ASIC implementation) that can be used to control the emission of each transmitter in the light transmitter array. As will be understood by those skilled in the art, the grouping scheme for the light transmitter array 41 described above actually involves the control module selecting and controlling a predetermined number of light transmitters to emit light simultaneously (also referred to as "together" in the specification), thereby eliminating overlap between the fields of view of the predetermined number of light transmitters that emit light simultaneously, and realizing no overlap between the fields of view of the predetermined number of light transmitters that emit light simultaneously within the detection range of the light detection device.

[0071] In some embodiments, the optical transmitters of the optical transmitter group can be integrated into at least one chip using a semiconductor process. For example, if the optical transmitter is a laser device, the chip is a laser device chip. By integrating multiple optical transmitters into one chip, the problem of large spacing between optical transmitters caused by packaging each single optical transmitter can be avoided, and a highly integrated optical transmitter array and corresponding optical transmitter group can be realized, contributing to reducing the volume of the optical detection device and improving the laser radar line density.

[0072] In some other embodiments, the entire light-emitting part can be integrated into one chip by semiconductor processing, and the optical transmitters can be grouped and the transmission order controlled by circuit connection, which can further reduce costs and improve processing efficiency.

[0073] For simplicity, the following description will be limited to the optical transmitter grouping for the optical transmitter array 41. FIG. 4C shows a schematic diagram of the optical transmitter grouping structure based on the exemplary structure of FIG. 4A. In this example, every eight optical transmitters arranged consecutively in a column direction constitute one unit, and two units in one column, or 16 optical transmitters, constitute one optical transmitter group, forming a total of eight optical transmitter groups, i.e., Bank0 to Bank7. As shown in FIG. 4D, one optical transmitter in each bank can be selected and activated for one optical signal transmission / reception. Therefore, eight optical transmitters emit light simultaneously during one signal transmission process, and are represented by black blocks distinct from the other blocks in the figure.

[0074] As can be seen from the above, by dividing the optical transmitters into groups and selecting each optical transmitter to emit light, the greater the number of optical transmitters included in each optical transmitter group, the greater the separation space between activated optical transmitters.

[0075] It should be noted that the optical transmitter grouping scheme shown in Fig. 4C is merely exemplary and is not limited to the illustrated scheme. For example, one bank may be composed of eight optical transmitters arranged consecutively in the column direction in the figure, or three or more units in one column may be composed of one bank, or an indefinite number of optical transmitters arranged discretely in different rows or positions may be composed of one bank, etc.

[0076] For example, the optical transmitter groups in adjacent optical transmitter rows or columns may be arranged alternately in the extension direction. For example, if one unit in the figure is one bank, it can be seen that the banks in adjacent columns are arranged with a staggered interval in the column direction. This example is similar to the staggered arrangement of optical transmitters in adjacent optical transmitter columns or rows described above for the purpose of increasing resolution.

[0077] In some examples, the signal transmission process in which each optical transmitter in each optical transmitter group and / or each optical detector in each optical detector group is activated varies. That is, only one optical transmitter in each optical transmitter group is activated during a single signal transmission process, and / or only one optical detector in each optical detector group is activated during a single signal transmission process. Specifically, in one signal transmission process, a1 in Bank0 is activated, b1 in Bank1 is activated, and one optical transmitter is selected and activated from each of the other banks. In the next signal transmission process, a2 in Bank0 is activated, b3 in Bank1 is activated, and so on, selecting and activating another optical transmitter from each of the other banks. After all optical transmitters in each bank have been activated, activation is repeated, taking turns. In this way, a1 and a2 do not emit light simultaneously during a single signal transmission process, and the same applies to b1 and b3.

[0078] Similarly, photodetectors in each photodetector group may be activated alternately during different signal transmission processes. For example, photodetector i2 in photodetector group Bank9 corresponds to photodetector a1 and forms one detection channel with photodetector a2, and photodetector j1 in Bank10 forms one detection channel with photodetector b1, and photodetector j2 forms one detection channel with photodetector b2. During one signal transmission process, when photodetectors a1 and b1 are activated, photodetectors i2 and j1 are also activated, and so on.

[0079] Figure 4C shows eight banks, each with 16 optical transmitters, for a total of 128 optical transmitters. When one optical transmitter and one optical detector constitute one detection channel, there are a total of 128 detection channels, or "128 lines." During each signal transmission, eight of the 128 detection channels operate together, and all detection channels are traversed through 16 signal transmissions. Each optical transmitter can employ, for example, a VCSEL laser device, which can achieve a very high vertical resolution of approximately 0.2° when the laser radar's vertical field of view is 25°.

[0080] The optical transmitter array shown in the examples of FIGS. 4A, 4B, and 4C is in the form of a linear array. The number of optical transmitters in the column and row directions corresponds to the column and row dimensions. In the figures, the column dimension of the optical transmitter array is shown to be significantly larger than the row dimension, i.e., the ratio of the column dimension to the row dimension is 3 times or more. As will be understood by those skilled in the art, in other examples, the row dimension of the optical transmitter array can also be significantly larger than the column dimension. In other words, when the optical transmitter array is a two-dimensional array, the dimensions in the two dimensions are significantly different, and the ratio between the two dimensions is greater than 3 or greater than 5. Whether the dimension is long or short corresponds to whether the number of optical transmitters is large or small and is also related to the field of view and resolution in the corresponding dimension. Different dimensions can be selected according to the field of view and resolution requirements. It can be understood that the dimensional ratios set out above apply not only to two-dimensional optical transmitter arrays but also to one-dimensional optical transmitter arrays, the difference being that the dimensional ratio of a two-dimensional optical transmitter array may be N:M, while the dimensional ratio of a one-dimensional optical transmitter array is N:1.

[0081] In a specific application scenario, the optical detection device can be realized as a laser radar applied to a moving vehicle (e.g., a car). Typically, in the field of laser radar, each detection produces one detection result (e.g., one point cloud map), which covers the entire horizontal and vertical field of view.

[0082] For example, in a road driving scene, obstacles may be people or vehicles on the road surface, which are very important for unmanned driving. Among the detection channels of a laser radar, the field of view of the central detection channel covers more people and vehicles on the road surface, and the closer a detection channel is to the edge, the farther it is from the obstacles on the road surface. It can be understood that the optical transmitters in the central region of the optical transmitter array belong to the central detection channel, and the optical transmitters in the edge regions of the optical transmitter array belong to the edge detection channel.

[0083] To improve short-range obstacle detection, laser radar can emit additional light for short-range measurement (e.g., 3 m) in addition to long-range measurement (e.g., 150 m) during a single detection (e.g., detection corresponding to one horizontal field of view). The long-range and short-range measurement results are then combined to obtain the detection result. In a specific example, short-range and long-range measurement operations can be achieved using different time-of-flight windows. A time-of-flight window refers to a time-of-flight range, calculated as t = 2 × d / c, where t is the time of flight from when the optical transmitter transmits a signal to when it receives an echo signal, d is the obstacle distance, c is the speed of light, and twice d represents the round-trip distance between the transmitted signal and the echo signal. For example, when detecting an object at a distance of 150 m, only echo signals obtained within a preset time-of-flight range within the 150 m range are received, and echo signals that are beyond or below this preset time-of-flight range are excluded.

[0084] In one embodiment, the long-range and short-range distances are complementary, for example, the long-range distance is greater than 3 m and the short-range distance is less than 3 m. In another embodiment, the long-range and short-range distances may overlap slightly, for example, the long-range distance is greater than 3 m and the short-range distance is less than 5 m, with the long-range and short-range distances having an overlapping detection distance of 2 m.

[0085] In possible examples, the distance corresponding to long-distance ranging operation may be 100m to 150m, or 150m to 200m, or 200m to 250m, and the distance corresponding to short-distance ranging operation may be 3m to 5m, 5m to 10m, etc. The lasers transmitted by different optical transmitters are emitted at different angles, and the spacing between different transmitted laser beams becomes larger when the distance is long. Therefore, when performing long-distance ranging operation, it is necessary to use more densely packed optical transmitters to ensure the density of the point cloud. When performing short-distance ranging, the density and number of optical transmitters can be reduced accordingly.

[0086] In a possible example, the short-range ranging operation and the long-range ranging operation can use detection channels that overlap partially or completely, for example, the optical transmitter in the central region in the first direction of the optical transmitter array is used for a long-range ranging distance of 250 m and a short-range ranging distance of 3 m. When long-range ranging is the main focus and short-range ranging is secondary, the frequency of operation in each detection and the resources of the detection channel can be biased toward the long-range ranging operation, for example, four long-range ranging operations followed by one short-range ranging operation.

[0087] In a possible example, during short-distance measurement, fewer optical transmitters are used, and the number of corresponding detection channels is correspondingly reduced. For example, for short-distance measurement, the selection may be limited to only channels close to the central region of the eight banks, e.g., a portion of <128 optical transmitters (e.g., 40) may be selected. If each optical transmitter corresponds to one detection channel, 40 detection channels are formed, and the 40 detection channels are polled in sequence to perform short-distance measurement. Optionally, the short-distance measurement and long-distance measurement operations may also differ in the channel polling method. For example, during one signal transmission process for each long-distance measurement operation, optical transmitters of one channel each from multiple banks in the central region (e.g., banks 2, 3, 4, and 5 in FIG. 4D) are selected and operated together. During one signal transmission process for each short-distance measurement operation, only one channel in one of the multiple banks in the central region is selected and operated.

[0088] In a possible example, there are multiple detection distances corresponding to the long-distance ranging operation, such as 150 m and 250 m. The closer an activated optical transmitter is to the center of the optical transmitter array, the farther the corresponding expected detection distance, i.e., the larger the expected detection time window. As an example, an optical transmitter closer to the center in the vertical center region of FIG. 4C provides a ranging time window of 250 m (window t = 2 × d / c) and is expected to be detectable at 250 m at the farthest, while an optical transmitter located relatively closer to the edge provides a ranging time window of 150 m and is expected to be detectable at 150 m at the farthest.

[0089] The above-mentioned activation methods of the optical transmitters are merely examples and are not intended to limit the scope of the present invention. For example, in other examples, multiple optical transmitters (e.g., in the same row) corresponding to one vertical field of view can be arranged, but the multiple light-emitting units do not emit light simultaneously (e.g., polling light emission), thereby increasing the service life and reliability of each light-emitting unit.

[0090] In some embodiments, the drive scheme of the optical transmitter array and corresponding driver circuits can be configured to provide individual control over each optical transmitter therein, so that the optical transmitters can be polled to emit light, emitted together, or any other combination of light emission schemes. For example, the optical transmitters in the optical transmitter array can be polled in any order, interval, signal characteristic (e.g., one or more combinations of wavelength, pulse width, number of pulses, pulse peak, and time interval between pulses), etc., thereby providing flexible electronic scanning (e-scanning).

[0091] In some examples, to reduce crosstalk between detection channels, the signal characteristics of the optical signals transmitted to each detection channel operating in the same signal transmission process are not completely identical. Here, the optical signals transmitted to each detection channel include a transmission signal and a corresponding echo signal. The optical detection device may further include a control module (e.g., implemented using an FPGA, SoC, or other ASIC) that can be used to determine the detection channel to which a signal belongs based on the signal characteristics.

[0092] Specifically, the optical detector converts the received optical signal into an electrical signal, and after undergoing certain signal processing (e.g., filtering, analog-to-digital conversion, etc.), transmits the electrical signal to the control module, which determines whether the signal characteristics of the echo signal match those of the signal transmitted by the optical transmitter of the corresponding detection channel, and if so, uses the echo signal in the corresponding detection channel to calculate the detection result, such as calculating the target distance, etc. In a specific example, the control module can be realized by, for example, a microcontroller unit (MCU), a programmable gate array (FPGA), or a system-on-chip (SoC).

[0093] In some examples, each optical transmitter is activated by a drive signal from a drive circuit, and the drive signal may be generated by the drive circuit of the optical transmitter. Optionally, the drive signal may include one or more pulsed electrical signals (e.g., periodic pulse signals), and thus the transmitted signals of the optical transmitters correspondingly include one or more pulsed optical signals. In corresponding examples, the signal characteristic dimensions may include one or more combinations of wavelength, pulse width, pulse number, pulse peak, and time interval between pulses.

[0094] Alternatively, in order to simplify calculations, based on the example where optical transmitters in the same bank do not need to emit light during the same signal transmission process, the signal characteristics of each optical transmitter in the same bank can be set to be the same, so that each bank has its own unique signal characteristics that are different from each other.

[0095] The principle of signal features of different dimensions will be explained by an example.

[0096] In an example where wavelength is a signal characteristic, the wavelengths of the transmitted signals from each optical transmitter group are not completely the same, and furthermore, the optical wavelengths of the transmitted signals from optical transmitters operating in the same signal transmission process are different. For example, BANK0, BANK1, BANK2, and BANK3 each have one optical transmitter transmitting a signal in the same signal transmission process, where BANK0 is a plurality of optical transmitters transmitting an optical signal with wavelength λ0, and correspondingly, BANK1 to BANK3 are optical transmitters transmitting optical signals with wavelengths λ1 to λ3, respectively, where λ0 ≠ λ1 ≠ λ2 ≠ λ3. Thus, in each signal transmission process, one optical transmitter is selected from each of the four banks to transmit an optical signal, and the wavelengths of the signals emitted by the four optical transmitters transmitting signals together in any signal transmission process are all different.

[0097] Furthermore, in the optical detector array, optical detector groups corresponding to the optical transmitter groups may be provided, and an optical filter unit may be provided upstream of the optical path of each optical detector in each optical detector group, and each optical filter unit may be configured to allow only echo signals of a wavelength corresponding to the detection channel to pass, thereby filtering out echo signals of other detection channels and interference from ambient light.

[0098] As another example, as shown in FIG. 5A, an optical transmitter array is divided into n optical transmitter groups. The optical wavelengths of the transmission signals of each optical transmitter group are different, λ1 to λn, respectively. This makes the optical transmitter array suitable for simultaneously transmitting up to n transmission signals. When optical transmitters from any of the n optical transmitter groups are selected and activated, the multiple optical transmitters transmitting together can emit signal beams of different wavelengths. When n optical transmitter groups are selected to be activated together, in one optical signal transmission and reception, each optical transmitter selects one optical transmitter to transmit a signal for detection. The transmission signal beam passes through the transmitting lens and is reflected by the target to form an echo signal. The wavelength of each echo signal is the same as the corresponding incident transmission signal, λ1 to λn. The n echo signals pass through the window, return to the optical detection device, pass through the receiving lens, and are transmitted to the optical detection array. In the optical detector array, n optical detector groups can be provided corresponding to n optical transmitter groups, and an optical filter unit can be provided in front of each optical detector in each optical detector group, and each optical filter unit can be configured to allow only echo signals of a wavelength corresponding to the detection channel to pass through. By selecting and activating one optical detector from one optical detector group in one optical signal transmission, the n optical detectors can each detect n echo signals without detecting echo signals of other wavelengths, thereby reducing interference.

[0099] In an example where pulse width is the signal characteristic, each transmission signal may include multiple pulses, and the ratio of these pulse widths may be set differently, for example, 2:3:1:..., which can be used as the signal characteristic of the transmission signal (and can be encoded to obtain a signal characteristic code). In the same signal transmission process, the pulse width ratios of the transmission signals of different detection channels operating together may be different. For example, this can be achieved by setting different pulse width ratios for different banks. For example, as shown in FIG. 5B, the multiple consecutive pulses included in the transmission signals of each optical transmitter in BANK 0 have a pulse width ratio of 1:2:1:..., and the multiple pulses included in the transmission signals of each optical transmitter in BANK 1 have a pulse width ratio of 1:2:3:..., and the pulse width ratios of each of the other banks are also different. Therefore, in the same signal transmission process, the pulse width ratios of the transmission signals of optical transmitters selected from different banks will be different from each other, and the pulse width ratios of the echo signals generated by each will also be different. By determining whether the pulse width ratio of the echo signal is the same as the pulse width ratio of the transmission signal of the main detection channel, it can be determined whether the echo signal belongs to the main detection channel. If the pulse width ratio of the echo signal is different from the pulse width ratio of the transmission signal of the main detection channel, it is filtered out as an interference signal. Thus, by using different pulse widths as signal characteristics, it is possible to distinguish between echo signals belonging to different detection channels.

[0100] In an example where the inter-pulse time interval is a signal feature, the ratio of the inter-pulse time intervals of the transmission signals of different detection channels operating together in the same signal transmission process is different. For example, this can be achieved by making the ratio of the inter-pulse time intervals of the transmission signals of different banks different. For example, as shown in Figure 5C, the ratio of the inter-pulse time intervals of multiple consecutive pulses included in the transmission signal of the optical transmitter in bank 0 is 2:3:1, and the ratio of the inter-pulse time intervals of multiple consecutive pulses included in the transmission signal of the optical transmitter in bank 1 is 2:2:3. As a result, the ratio of the inter-pulse time intervals of the echo signals generated by each is also different. The echo signals belonging to different detection channels can be distinguished by determining whether the ratio of the inter-pulse time intervals of the echo signals matches the ratio of the inter-pulse time intervals of the transmission signals of this detection channel.

[0101] In the case where the number of pulses is the signal characteristic, the numbers of pulses contained in the transmission signals of different detection channels operating together in the same signal transmission process are different. For example, the numbers of pulses contained in the transmission signals of the optical transmitters of different banks are different, and therefore the number of pulses in the echo signals generated by each is also different. The echo signals of different detection channels can be distinguished by determining whether the number of pulses in the echo signal matches the number of pulses in the transmission signal of the detection channel.

[0102] In an example where pulse peaks (corresponding to optical intensity peaks or peaks converted into electrical signals) are used as signal features, the ratios of the peak intensities of multiple pulses contained in the transmission signals of different detection channels operating together in the same signal transmission process are different. For example, this can be achieved by making the ratios of the pulse peak intensities of multiple pulses contained in the transmission signals of optical transmitters in different banks different. For example, the pulse peak ratios of the multiple pulses contained in the transmission signals of the optical transmitter in bank 0 are X:Y:Z:..., and the pulse peaks of one or more pulses contained in the transmission signals of the optical transmitter in bank 1 are all W:X:Y.... As a result, the pulse peak ratios of the echo signals generated by each are also different, and the belonging of the echo signals of different detection channels can be distinguished by determining whether the pulse peak intensity ratios of the echo signals match the pulse peak intensity ratios of the transmission signals of this detection channel.

[0103] Additionally, the above signal characteristics can be combined to produce signal characteristics for optical signals of different detection channels.

[0104] It should be noted that for the above ratios, such as the pulse width ratio, the pulse interval ratio, and the pulse peak intensity ratio, the integer ratios are merely exemplary, and in actual applications, the ratios may be any numerical values.

[0105] In one or more of the various embodiments in which the associated detection channel is distinguished by the signal characteristics, it can be understood that the optical detection device may be a laser radar, and that highly flexible detection scanning can be achieved by polling or freely selecting any one laser device or any combination of laser devices (addressable by the laser device), thereby achieving at least multiple objectives.

[0106] On the other hand, it is possible to realize free selection of detection targets and areas. Specifically, if the optical detection device is a laser radar, it can be mounted on a moving vehicle (e.g., an intelligent driving vehicle, etc.) and perform detection as it moves. If a specific target or area of ​​interest is identified based on point cloud data in a certain scan, the next time it is necessary to scan again, it is possible to select only this specific target or area of ​​interest to be turned on / scanned through free addressing. For example, this can be applied to implementing encrypted scanning of a specific target or area of ​​interest.

[0107] On the other hand, crosstalk between detection channels can be reduced. Because the specific light-emitting or scanning area can be freely selected, laser devices with as large a physical distance as possible can be selected during detection, as in the embodiment of FIG. 4D, and light can be emitted during the same signal transmission process. This significantly reduces crosstalk between detection channels, achieving a higher signal-to-noise ratio and detection effect than current laser radar products.

[0108] On the other hand, it can also reduce the number of detections required to collect point cloud data and reduce the overall power consumption of the optical detection device, because with the technological trend of increasing the number of lines, the larger the number of lines, the higher the corresponding energy consumption, which causes extra heat dissipation and reliability problems.

[0109] In the above example, each optical transmitter in the optical transmitter array can be activated by a drive control signal of a drive circuit. Illustratively, the signal characteristics of the transmission signal of each optical transmitter can be determined by the signal characteristics of the drive control signal.

[0110] FIG. 6 shows a schematic circuit diagram of a driving circuit for an optical transmitter array in one embodiment of the present application.

[0111] The drive circuit a driving module corresponding to each optical transmitter belonging to each detection channel; and a multiplexer MUX including an input terminal to which a drive signal Trigger for controlling the drive module to activate the optical transmitter is input, and a plurality of output terminals connected in one-to-one correspondence to each drive module, and selected to be connected to the input terminal and output the drive signal.

[0112] In the drawing, the number of driver modules is exemplarily shown as 16, corresponding to detection channels 0 to 15, and are labeled as driver modules 0 to 15. The structure of driver module 0 is exemplarily shown in the drawing, and the other driver modules may have the same structure. The optical transmitters of the 16 detection channels are labeled LD0 to LD15.

[0113] The driving module includes an NMOS tube M1, a PMOS tube M2, a resistor R1, a high-voltage diode D1, a constant-voltage diode D2, and an energy storage capacitor C.

[0114] A power supply line is provided, accessing the power supply voltage HVDD. A line control unit K (which may be realized by a switch) is connected in series to the power supply line. The input terminal of the line control unit accesses HVDD and its output terminal outputs HVDD1. The output terminal of the line control unit K is connected to R1, the positive terminal of D1, the negative terminal of D2, and the source electrode of M2, respectively. The other terminal of resistor R1 is connected to the drain electrode of M1, and the grid electrode of M1 is connected to one output terminal of multiplexer MUX, which is controlled by Trigger to be turned on or off. D1, D2, and R1 are connected in parallel, and the negative terminal of D1 and the positive terminal of D2 are connected to the drain electrode of M1 and the grid electrode of M2. The drain electrode of M2 is connected to one terminal of the optical transmitter, and the other terminal of the optical transmitter is grounded. One terminal of capacitor C is connected to the power supply line and the other terminal is grounded.

[0115] Alternatively, a control signal, such as an 8-bit digital signal, can be input to the source electrode of M1. The source electrode of M1 can be connected to the output terminal of a transient digital-to-analog converter (IDAC). The control signal is input to the input terminal of the transient digital-to-analog converter, converted into an analog voltage, and applied to the source electrode of M1. The level of the analog voltage corresponding to this control signal controls Vgs, which in turn controls the open / closed states of M1 and M2. Alternatively, the source electrode of M1 can be directly connected to a low potential, for example, grounded.

[0116] In the inactive state, the line control unit K is turned on, HVDD1=HVDD, M1 is turned off and HVDD acts on the M2 grid electrode, M2 is also turned off and the optical transmitter LD0 does not emit light.

[0117] In the working state, Trigger selects detection channel 0 through the multiplexer, that is, strobe driving module 0. When Trigger is at high potential, the corresponding line control unit K cuts off the power of HVDD, and when the source electrode of M1 is at low potential, Trigger controls M1 to turn on, and reduces the voltage of the grid electrode of M2 to turn on M2. C starts discharging to maintain HVDD1, and accordingly generates a driving current at the drain electrode of M2 to flow through the optical transmitter LD0 and drive its light emission.

[0118] When the active state is switched to the inactive state, C continues to charge, M1 and M2 are turned off, and the optical transmitter LD0 does not emit light.

[0119] In some cases, the charging speed of the capacitor is slow relative to the switching of the optical transmitter's operating state. To support multi-pulse emission of the optical transmitter (when the trigger is a multi-pulse signal), a capacitor C with a large capacitance can be used. This allows the capacitor to drive the optical transmitter and emit light by discharging only a small portion of its stored power each time light is emitted. Even if the capacitor cannot recharge the power consumed during the time interval Δt between two light emissions, the remaining power can be used to drive the laser again. Because the capacitor's discharge current decreases as the power decreases, to avoid the discharge current (the driving current of the laser device) being too small due to low remaining power in the capacitor when the next light is emitted, the capacitance of the capacitor C can be selectively set to discharge a predetermined number of times. For example, the amount of discharge required to drive one light emission can be within 10% of the total stored power of the capacitor C.

[0120] As can be seen from this, the multi-pulse signal of the driving signal Trigger can control the transmission signal of the optical transmitter to the form of a corresponding multi-pulse signal, i.e., the signal characteristics of Trigger are related to, e.g., match, the signal characteristics of the transmission signal. Furthermore, by setting different signal characteristics of Trigger for different detection channels, different transmission signals can be achieved for different detection channels. Because the transmission signal and the echo signal have the same signal characteristics, the signal characteristics of the optical signals in different detection channels can be different, thereby realizing that the detection channel to which the echo signal belongs can be determined based on the signal characteristics, and crosstalk between detection channels can be reduced.

[0121] For example, the double pulse example shown in Figure 7 corresponds to the example where the number of pulses is used as a signal feature. First, Trigger 1 drives the optical transmitter to generate pulse signal pulse 1, and after a time interval Δt, Trigger 2 drives the laser device again to generate pulse pulse 2. The number of pulses of multiple channels that emit light together can be different; that is, the optical transmitters of different channels are driven by different numbers of trigger signals to transmit light-emitting signals with different numbers of pulses.

[0122] For the above example where pulse time intervals are used as signal features, reference can be made to FIG. 7 and FIGS. 8A-8D.

[0123] The pulse time intervals between the multiple pulse signals included in the optical transmitter signal are determined by the time intervals between the trigger signals. Therefore, different sequences can be coded for the trigger signals corresponding to multiple optical transmitters that emit light together. In Figures 7 and 8A-8D, the optical pulse time intervals are illustratively obtained based on the time intervals between the rising edges of adjacent trigger pulses, and the corresponding time axes (not shown) from right to left indicate time from the past to the present.

[0124] For example, optical transmitters belonging to different detection channels all transmit double-pulse transmission signals, such as those shown in FIG. 7, but the Δt of the transmission signals of different detection channels are different to distinguish their echo signals.

[0125] 8A to 8D show possible pulse coding forms of the driving signals Trigger of BANK1 to BANK4 corresponding to different detection channels, respectively, in which it is exemplarily shown that the Trigger of each detection channel includes three pulses.

[0126] Specifically, in FIG. 8A, Trigger of BANK1 includes three pulse signals, Trigger30, Trigger20, and Trigger10, and the pulse time interval between Trigger30 and Trigger20 is Δt20, and the pulse time interval between Trigger20 and Trigger10 is Δt10.

[0127] In FIG. 8B, Trigger of BANK2 includes three pulse signals, Trigger31, Trigger21, and Trigger11, and the pulse time interval between Trigger31 and Trigger21 is Δt21=Δt20, and the pulse time interval between Trigger20 and Trigger10 is Δt11≠Δt10.

[0128] In FIG. 8C, Trigger of BANK3 includes three pulse signals, Trigger32, Trigger22, and Trigger12, and the pulse time interval between Trigger32 and Trigger22 is Δt21≠Δt20, and the pulse time interval between Trigger22 and Trigger12 is Δt11=Δt10.

[0129] In FIG. 8D, Trigger of BANK4 includes three pulse signals, Trigger33, Trigger23, and Trigger13, and the pulse time interval between Trigger33 and Trigger23 is Δt23≠Δt20, and the pulse time interval between Trigger22 and Trigger12 is Δt13≠Δt10.

[0130] As can be seen from the above, the light emission signals of the four detection channels are coded so that the ratios of the pulse time intervals of each multi-pulse are not exactly the same, and Δt1 may be different, Δt2 may be different, either Δt1 or Δt2 may be different, or both Δt1 and Δt2 may be different, etc.

[0131] In the above example where pulse width is a signal characteristic, the ratio of the pulse widths of the multiple pulse signals in the Trigger of different detection channels may be different. The pulse width of the pulse signal included in the transmission signal varies with the pulse width of the Trigger signal, and the pulse width of the Trigger signal may have a positive correlation with the pulse width of the transmission signal. Therefore, as shown in Figure 9, by changing the pulse width of the Trigger signal, the multiple pulses emitted by the laser device can have pulse width coding. Figure 9 shows a schematic waveform diagram of the Trigger of one detection channel, and the pulse width ratios among the three pulse signals Trigger1, Trigger2, and Trigger3 included therein are configurable.

[0132] It should be noted that although there may be variations such as pulse broadening in the echo signal, in the echo signal reflected from the same target, the pulse widths of multiple pulse signals should change at equal ratios, and therefore, it is possible to determine whether or not an echo is valid depending on the ratio of the pulse widths between the multiple pulse signals in the echo signal.

[0133] The principle of the above example in which intensity coding is used as a signal feature is the same as pulse width coding, in that the optical transmitter transmits a transmission signal of multiple pulses at a specific intensity ratio, and the ratio of the signal intensities of the multiple pulses emitted by multiple lasers emitting light together is different, and the multi-pulse intensity ratio of the echo is determined to determine whether it is a valid echo.

[0134] In addition, the signal features of different dimensions can be combined. For example, some detection channels emit double pulses, some channels emit triple pulses, some detection channels that emit double pulses perform sequence coding, pulse width coding, intensity coding, etc. between the double pulses, and some detection channels that emit triple pulses also perform sequence coding, pulse width coding, intensity coding, etc. between the triple pulses, so that the combined signal features corresponding to the multiple channels operating together can be different from one another.

[0135] In addition, to further prevent crosstalk, in some embodiments, the control module in the optical detection device can further continuously perform the signal transmission process of "sending a transmitted signal - receiving an echo signal" more than once for the same detection channel, and compare the time of flight (TOF) values ​​calculated by measuring multiple times (e.g., twice). If the time of flight values ​​measured multiple times match (the same or the error may be less than a preset threshold), it determines that the detection result of the detection channel is valid; otherwise, it determines that the detection channel is affected by crosstalk and discards the detection result.

[0136] The above examples are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Those skilled in the art may modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical concept disclosed in the present application should be included in the claims of the present application.

Claims

1. an optical transmitter array including a plurality of optical transmitters configured to output transmission signals, the optical transmitter array including N mutually offset rows of optical transmitters, the optical transmitters in each row extending along a first direction, N>1; the optical transmitter array including a plurality of optical transmitter groups, each of the plurality of optical transmitter groups including a plurality of units each including one or more optical transmitters, spaced apart from each other in a corresponding row along the first direction; first and second optical transmitter groups adjacent to each other among the plurality of optical transmitter groups being spaced apart from each other along a second direction perpendicular to the first direction and being offset from each other along the first direction; and one optical transmitter in the second optical transmitter group being located between a first optical transmitter in a first unit of the first optical transmitter group and a second optical transmitter in a second unit of the first optical transmitter group along the first direction; an optical detector array including a plurality of optical detectors configured to detect echo signals reflected after the transmitted signal encounters an obstacle, the optical transmitter array and the optical detector array forming a plurality of detection channels, each detection channel including at least one optical transmitter and at least one optical detector; a control module for selecting a plurality of predetermined optical transmitters to emit light simultaneously in a single signal transmission process from transmission of a transmission signal to detection of a corresponding echo signal, wherein the fields of view of the predetermined plurality of optical transmitters selected to emit light simultaneously are separated from each other within a detection distance; An optical detection device comprising:

2. 2. The optical detection device of claim 1, wherein the optical transmitter array is a two-dimensional array, the ratio of the dimensions of the two dimensions being greater than 3 or greater than 5.

3. The optical detection device of claim 1, wherein a plurality of activated optical transmitters in the optical transmitter array form a plurality of active detection channels with a plurality of activated optical detectors in the optical detector array, the optical detector array includes a plurality of optical detector groups, and each of the activated optical transmitters belongs to a different optical transmitter group and / or each of the activated optical detectors belongs to a different optical detector group.

4. An optical detection device as described in claim 1, characterized in that each optical transmitter in each of the optical transmitter groups and / or each optical detector in each of the different optical detector groups is activated alternately during multiple signal transmission processes.

5. 2. The optical detection device according to claim 1, characterized in that it has a first separation space between two activated optical transmitters in two adjacent optical transmitter groups and / or a second separation space is formed between activated optical detectors in two adjacent optical detector groups during the same signal transmission process.

6. 2. The optical detection device of claim 1, wherein each optical transmitter group includes a predetermined number of optical transmitters, and the optical transmitters of the optical transmitter groups are integrated into at least one chip.

7. 2. The optical detection device according to claim 1, wherein a plurality of optical transmitters of the optical transmitter group are coupled to at least one selection unit, the selection unit being adapted to select an optical transmitter according to an external signal.

8. 2. The optical detection device of claim 1, wherein the optical detector array includes M mutually offset rows of optical detectors, each row of optical detectors extending along the first direction, and M>1.

9. 2. The optical detection device according to claim 1, wherein the signal characteristics of the optical signals transmitted through each detection channel are not completely the same during the same signal transmission process.

10. 10. The optical detection device of claim 9, wherein the control module is adapted to determine whether the signal characteristics of the echo signal detected by the optical detector match the signal characteristics of the signal transmitted by the optical transmitter of the corresponding detection channel, and if so, to use the echo signal in the corresponding detection channel to calculate the distance to the target.

11. 10. The optical detection device of claim 9, wherein the transmission signal transmitted by the optical transmitter includes one or more pulse signals, and the signal characteristic dimensions include one or more combinations of wavelength, pulse width, number of pulses, pulse peak, and time interval between pulses.

12. The optical detection device of claim 11, wherein 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 ratio of pulse widths between multiple pulses.

13. The optical detection device of claim 9, wherein the signal characteristics in the signal intensity 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.

14. 2. The optical detection device of claim 1, wherein the wavelengths of the transmitted signals of the optical transmitters in different detection channels operating in the same signal transmission process are different, and an optical filter unit is provided in front of the optical detector of each operating different detection channel to pass only the echo signal of the wavelength corresponding to the detection channel.

15. 2. The optical detection device of claim 1, further comprising a control module for controlling the optical transmitter array and the optical receiver array to continuously detect one detection channel multiple times during one signal transmission process to obtain time-of-flight values, comparing the time-of-flight values ​​detected multiple times, and determining that the detection result of the detection channel is valid if the comparison results are consistent, or discarding the detection result if not.

16. 10. The optical detection device of claim 1, including a laser radar.

17. activating a plurality of optical transmitters in the optical transmitter array to transmit a transmit signal; activating a plurality of photodetectors in the photodetector array; Including, A method for performing optical detection using an optical detection device described in any one of claims 1 to 16, characterized in that the activated optical transmitters form multiple detection channels in an active state with the activated optical detectors, respectively, and each of the activated optical transmitters belongs to a different optical transmitter group, and / or each of the activated optical detectors belongs to a different optical detector group.

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