Collector, ranging system and method of manufacturing a collector

Abstract

The application belongs to the technical field of optics, and provides a collector, a ranging system and a method for manufacturing the collector. The collector comprises k shared TDC circuits, a pixel array comprising a plurality of macro-pixels, the number of the macro-pixels being at least s times the number of the shared TDC circuits, each macro-pixel comprising one or more pixels, the pixel array being configured to comprise at least two sub-pixel arrays, each sub-pixel array comprising m rows and n columns of macro-pixels, and each macro-pixel in each sub-pixel array being connected to a different shared TDC circuit, so that all the macro-pixels in the pixel array share the k shared TDC circuits, s is a positive integer greater than 1, n and m are positive integers greater than or equal to 1, and the product of n and m is k. The embodiment of the application can make the ranging system compatible with multiple scanning modes by using shared TDC circuits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optics, and particularly relates to a collector, a ranging system and a method for manufacturing a collector. BACKGROUND

[0002] The ranging system refers to a distance measurement system, which may refer to a laser radar in some scenarios. The laser radar can be divided into a mechanical laser radar, a full solid-state laser radar and a hybrid solid-state laser radar according to a scanning mode.

[0003] The collector of the full solid-state laser radar generally includes a receiving chip (pixel array), and the pixel array is connected with a time-to-digital convertor (TDC) circuit to process a photon signal of the pixel by the TDC circuit to realize ranging. During ranging, a laser is generally emitted by a transmitter, and a light signal reflected by a target is collected by a corresponding pixel on the pixel array to generate a photon signal. A mode in which part or all of the pixels in the pixel array are turned on is referred to as a scanning mode. The scanning mode of the pixel array can be commonly divided into one-dimensional scanning (such as shown in FIG. 1) and two-dimensional scanning (such as shown in FIG. 2). Figure 1a Figure 1b In the related art, only one scanning mode can be executed by using the pixel array, and the connection relationship between the TDC circuit and the pixel array determines the selectable scanning mode of the pixel array in the measurement process, and a receiving chip compatible with multiple scanning modes has not yet appeared. In the conventional practice, a TDC circuit is generally allocated to each pixel to realize arbitrary control of the pixel array, but this design will cause high cost and large volume of the receiving chip. SUMMARY

[0004] Embodiments of the present application provide a collector, a ranging system and a method for manufacturing a collector, which can enable the ranging system to be compatible with multiple scanning modes by using shared TDC circuits.

[0005] A first aspect of embodiments of the present application provides a collector, including: k shared TDC circuits; a pixel array including a plurality of macro-pixels, the number of the macro-pixels being at least s times the number of the shared TDC circuits, each of the macro-pixels including one or more pixels; wherein the pixel array is configured to include at least two sub-pixel arrays, each of the sub-pixel arrays including m rows x n columns of the macro-pixels, each of the macro-pixels in each of the sub-pixel arrays being connected with a different shared TDC circuit, so that at least two of the macro-pixels in the pixel array are connected with one shared TDC circuit; wherein s is a positive integer greater than 1, n and m are positive integers greater than or equal to 1, and the product of n and m is k.

[0006] ​The second aspect of the embodiment of the present application provides a ranging system, comprising: a transmitter, a collector as described in the first aspect, and a control and processing circuit connected with the transmitter and the collector; wherein the transmitter comprises a light source array composed of a plurality of light emitting elements, for emitting a laser beam to a target; the collector is used for collecting the laser beam reflected by the target; the control and processing circuit is used for synchronously controlling the transmitter and the collector, and calculating the flight time of the laser beam from emission to collection to obtain the distance of the target.

[0007] The third aspect of the embodiment of the present application provides a ranging system, comprising: a transmitter, a collector, and a control and processing circuit; the transmitter comprises a light source array composed of a plurality of light emitting elements, for emitting a laser beam to a target; the collector comprises a pixel array composed of a plurality of macro-pixels, the pixel array is configured to contain at least two sub-pixel arrays, each sub-pixel array comprises m rows and n columns of macro-pixels, and each macro-pixel comprises one or more pixels; the control and processing circuit comprises a preset k shared TDC circuit; wherein each macro-pixel in the sub-pixel array is connected with different shared TDC circuits respectively, and all the macro-pixels share k shared TDC circuits; wherein n and m are positive integers greater than or equal to 1, and the product of n and m is k.

[0008] The fourth aspect of the embodiment of the present application provides a method for manufacturing a collector, comprising: providing k shared TDC circuits; configuring two sub-pixel arrays composed of m rows and n columns of macro-pixels according to the k shared TDC circuits, wherein the product of n and m is k; setting each macro-pixel in any one of the sub-pixel arrays to be connected with different shared TDC circuits respectively; and configuring a plurality of sub-pixel arrays to form a pixel array.

[0009] In the embodiments of the present application, the collector can include k shared TDC circuits; a pixel array including a plurality of macro-pixels, the number of macro-pixels being at least s times the number of shared TDC circuits, each macro-pixel including one or more pixels; the pixel array is configured to include at least two sub-pixel arrays, each sub-pixel array including m rows x n columns of macro-pixels, each macro-pixel in each sub-pixel array being connected to a different shared TDC circuit, so that at least two macro-pixels in the pixel array are connected to one shared TDC circuit; wherein s is a positive integer greater than 1, n and m are positive integers greater than or equal to 1, and the product of n and m is k. In one aspect, the same shared TDC circuit can be connected between macro-pixels, thereby reducing the number of TDC circuits. Macro-pixels connected to different shared TDC circuits can be turned on at the same time. Since the pixel array includes at least two sub-pixel arrays each including m rows x n columns of macro-pixels, all macro-pixels in any one of the sub-pixel arrays can be controlled to be turned on. Turning on all macro-pixels in one of the sub-pixel arrays is a scanning mode. Therefore, the distance measuring system can be compatible with multiple scanning modes. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0011] Figure 1a is a schematic diagram of one-dimensional scanning in the related art;

[0012] Figure 1b is a schematic diagram of two-dimensional scanning in the related art;

[0013] Figure 2 is a structural schematic diagram of a distance measuring system provided by the embodiments of the present application;

[0014] Figure 3 is a structural schematic diagram of a first pixel array provided by the embodiments of the present application;

[0015] Figure 4 is a structural schematic diagram of a second pixel array provided by the embodiments of the present application;

[0016] Figure 5 is a structural schematic diagram of a third pixel array provided by the embodiments of the present application;

[0017] Figure 6 is a structural schematic diagram of a distance measuring system provided by the embodiments of the present applicationFigure Two ;

[0018] Figure 7 Wall surface light spot distribution schematic diagram when the transmitter provided by the embodiment is provided with a distortion lens;

[0019] Figure 8 Receiving light spot distribution schematic diagram when the collector provided by the embodiment is provided with a distortion lens;

[0020] Figure 9 Structural schematic diagram of a light source array provided by the embodiment of the application;

[0021] Figure 10 Timing schematic diagram of the light source array firing provided by the embodiment of the application;

[0022] In the drawings, various reference signs represent:

[0023] 11-transmitter; 12-collector; 110-light source array; 120-pixel array. DETAILED DESCRIPTION

[0024] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] The ranging system, i.e., the distance measurement system, can refer to a laser radar in some scenarios. The laser radar can be divided into a mechanical laser radar, a full solid-state laser radar and a hybrid solid-state laser radar according to the scanning mode. The collector of the full solid-state laser radar generally includes a receiving chip (pixel array), and the pixel array is connected with a Time to Digital Convertor (TDC) circuit to process the photon signal of the pixel by the TDC circuit, so as to realize ranging. During ranging, the laser is generally emitted by the transmitter, and the corresponding pixel on the pixel array is activated to detect the reflection light of the target on the laser to generate a photon signal. The manner of controlling part or all of the pixels in the pixel array to be turned on is referred to as a scanning mode, and the scanning mode of the pixel array can be commonly divided into one-dimensional scanning and two-dimensional scanning. The one-dimensional scanning refers to that one column or one row of pixels can be simultaneously controlled to be turned on, as shown in FIG. 1, and the two-dimensional scanning refers to that a block of multiple rows x multiple columns of pixels can be simultaneously controlled to be turned on, as shown in FIG. 2. Figure 1a Figure 1b

[0026] ​​In the related art, only one scanning mode can be performed by using a pixel array, and the connection relationship between the TDC circuit and the pixel array determines the selectable scanning mode of the pixel array in the measurement process. There is no receiving chip that can be compatible with multiple scanning modes. If different scanning modes are to be performed by using the same pixel array, a TDC circuit needs to be allocated to each pixel to achieve arbitrary control of the pixel array. However, this design will cause the receiving chip to have a high cost and a large size, which is not conducive to miniaturization design.

[0027] To solve the above technical problems, the present application provides a shared connection mode of macro-pixels and TDC circuits, and thus designs a collector and a ranging system.

[0028] To illustrate the technical solutions of the present application, specific embodiments are described below.

[0029] Figure 2 A structure diagram of a ranging system provided by an embodiment of the present application is shown. In the embodiment of the present application, the ranging system can include a transmitter 11 and a collector 12. In some embodiments, the ranging system can further include a control and processing circuit (not shown in the figure) connected to the transmitter 11 and the collector 12.

[0030] The transmitter 11 is also referred to as a projection module (TX module), which includes a plurality of light emitting elements. The light emitting elements are used to emit laser beams to a target. The target can be any object within the FOV of the ranging system, such as a person, a vehicle, etc. The laser beams are reflected by the target to form reflected light incident on the collector 12 after irradiating the target. The collector 12 is also referred to as a receiving module (RX module), which can be used to collect the laser beams reflected by the target to generate a photon signal. The control and processing circuit can be used to synchronously control the transmitter 11 and the collector 12, process the photon signal, calculate the flight time of the laser beams from emission to collection, and obtain the distance between the target and the ranging system to achieve ranging.

[0031] In the embodiments of the present application, the collector 12 described above can include a preset k shared TDC circuits and a pixel array 120 composed of a plurality of macro-pixels, the number of macro-pixels in the pixel array 120 being an integer multiple of the number of shared TDC circuits. Each macro-pixel includes one or more pixels, and each pixel is a single photon avalanche diode (SPAD). Since the reflected light is incident on the pixel array 120 to form a light spot, the size of the light spot is larger than the photosensitive area of a single pixel, and therefore a plurality of pixels are usually combined together to collect the photon signals in the reflected light spot, and these pixels activated at the same time to receive the same light spot constitute a macro-pixel. Usually, when setting, the light-emitting elements have a one-to-one correspondence with the macro-pixels, that is, the light signals emitted by each light-emitting element are incident in the corresponding macro-pixel.

[0032] It should be understood that the total number of macro-pixels in the pixel array 120 and the total number of shared TDC circuits k can be selected according to actual conditions, and preferably the total number of macro-pixels is s x k, and s and k can be positive integers greater than 1.

[0033] Figure 3 The structure of the pixel array 120 of the collector 12 is shown. A collector includes k shared TDC circuits and a pixel array 120, the pixel array including a plurality of macro-pixels, the number of macro-pixels being at least s times the number of shared TDC circuits, each macro-pixel including one or more pixels; the pixel array is configured to include at least two sub-pixel arrays, each sub-pixel array including m rows x n columns of the macro-pixels, each macro-pixel in each sub-pixel array being connected to a different shared TDC circuit, so that at least two macro-pixels in the pixel array are connected to one shared TDC circuit; wherein s is a positive integer greater than 1, n and m are positive integers greater than or equal to 1, and the product of n and m is k.

[0034] Each grid represents a macro-pixel, and the numbers on each grid represent the shared TDC circuits connected to the macro-pixel, and the same numbers represent the same shared TDC circuit. In the embodiments of the present application, the pixel array 120 can include at least two sub-pixel arrays composed of m rows x n columns of macro-pixels, each macro-pixel in any one of the sub-pixel arrays in the pixel array 120 being connected to a different shared TDC circuit, and all the macro-pixels in the pixel array 120 sharing k shared TDC circuits. Figure 3The solid-line boxes 31, 32, and 33 in FIG. 1 represent a sub-pixel array. Here, n and m are positive integers greater than or equal to 1, and the product of n and m is k. For example, when the total number of shared TDC circuits k is 9, 9 = 1 x 9 = 3 x 3 = 9 x 1. Thus, the first sub-pixel array can be a sub-pixel array composed of 1 row x 9 columns of macro-pixels, the second sub-pixel array can be a sub-pixel array composed of 3 rows x 3 columns of macro-pixels, and the third sub-pixel array can be a sub-pixel array composed of 9 rows x 1 column of macro-pixels. When configuring the pixel array, two of the sub-pixel arrays can be selected to design the pixel array 120. For example, the first and second sub-pixel arrays are selected to design the pixel array 120, as shown in FIG. 1, and the 81 macro-pixels in the pixel array 120 share the 9 shared TDC circuits. Figure 3

[0035] In some embodiments, the collector 12 can further include a pixel driving circuit connected to the pixel array 120. The pixel driving circuit can be used to configure the j macro-pixels in the pixel array 120 to be turned on, so that the j macro-pixels turned on are used as working pixels. Here, j is a positive integer greater than or equal to 1 and less than or equal to k, and the j working pixels are connected to different shared TDC circuits. That is, the macro-pixels connected to different shared TDC circuits can be turned on at the same time under the driving of the pixel driving circuit. The working pixels are in a working state, and the j working pixels in the working state can be used for detection and collection of reflected light to generate a photon signal. The shared TDC circuits connected to the j working pixels can be used to process the photon signal of the corresponding working pixel (i.e., the connected working pixel).

[0036] It should be noted that one TDC circuit can only receive the sampling signal (photon signal) of one macro-pixel, and it should be understood that the aforementioned scanning mode refers to the simultaneous turning on of one or more macro-pixels for scanning. Thus, when j is equal to 1, the pixel array 120 can perform point scanning; when j is greater than 1, the pixel array 120 can simultaneously perform multi-point scanning. Moreover, when j is equal to k, since the pixel array 120 includes at least two sub-pixel arrays composed of m rows x n columns of macro-pixels, all macro-pixels in any one of the sub-pixel arrays can be controlled to be turned on. Turning on all macro-pixels in one of the sub-pixel arrays is a scanning mode, and in this case, the distance measuring system can be compatible with multiple scanning modes.

[0037] The foregoing example of the total number of shared TDC circuits k being 9 is continued. As shown in FIG. 2, the connection mode of the pixel array 120 is different from that of the pixel array 120 in FIG. 1. Thus, the 81 macro-pixels share the 9 shared TDC circuits. Figure 3 Figure 3 ​​As shown in the solid line frame 31, the scanning mode is row scanning (one-dimensional scanning); it is also possible to actuate a block (multiple rows × multiple columns) of macro pixels for scanning at a time, such as Figure 3 As shown in the solid-line boxes 32 and 33, the scanning method is block scanning (two-dimensional scanning). The row of macropixels or block of macropixels mentioned here corresponds to a sub-pixel array described above. Actuating a row of macropixels or a block of macropixels refers to turning on any row or block (multiple rows x multiple columns) of macropixels in pixel array 120.

[0038] Figure 3 In the implementation manner, when designing the collector, the total number k of shared TDC circuits is first determined to be 9. According to the factorization 9=1×9=3×3=9×1, two matrix sub-area configurations are arbitrarily selected to set corresponding to two different scanning modes. For example, 1 row×9 columns and 3 rows×3 columns are selected for setting. Then, the row scan is a row of 9 macro pixels, and the block scan is 3 rows×3 columns of macro pixels. The pixel array 120 can be filled as shown in the following table. Then, the spaces in the table are filled to ensure that the pixels in each matrix sub-area are connected to different shared TDC circuits, and the following is obtained. Figure 3 The connection between the pixel array 120 and the shared TDC circuit is shown. In addition, this application does not limit whether multiple rows or blocks of macro pixels need to be scanned in a certain scanning order.

[0039]

[0040]

[0041] Figure 4 The total number k of shared TDC circuits is 9. Figure 3 Another different connection method, for example, select 1 row × 9 columns and 9 rows × 1 column to set. This connection method can realize row scanning (such as Figure 4 41 in the solid line frame) and column scan (as shown in FIG. Figure 4 (shown in the solid line frame 42 in FIG) two one-dimensional scanning modes. Of course, as Figure 4 As shown, this connection method can also achieve 3 rows × 3 columns of block scanning in some areas (such as Figure 4 (as shown in the solid line box 43 in the figure), and this block scanning can be achieved in any 3-row × 3-column matrix sub-region. Therefore, when manufacturing the collector 12, the macro pixels and the shared TDC circuit can be connected according to the requirements of the two sub-pixel arrays (two scanning modes). After manufacturing, the resulting collector 12 can sometimes have more than two scanning modes.

[0042] It should be understood that according to the preset total number k of shared TDCs, k can be factorized, and the design requirements of two sub-pixel arrays are selected according to the factorization, so as to determine the connection relationship between the macro-pixels and the shared TDCs when the required at least two scanning modes are implemented. The formed one pixel array 120 (the total number of macro-pixels is less than or equal to k rows x k columns) can also form a larger pixel array 120 by copying. For example, as shown in Figure 5 if there are 32 shared TDCs, a pixel array 120 composed of 16 rows x 16 columns of macro-pixels can be configured. Specifically, the 32 shared TDCs can be factorized into 1 x 32, 2 x 16, 4 x 8, 8 x 4, 16 x 2, and 32 x 1. According to the above decomposition forms, any two matrix sub-regions with the number of rows less than or equal to 4 and the number of columns less than or equal to 16 are selected to configure a small pixel array composed of 4 rows x 16 columns of macro-pixels. The small pixel array is copied multiple times to form a large pixel array, for example, a pixel array 120 composed of 16 rows x 16 columns of macro-pixels is formed by four small pixel arrays each composed of 4 rows x 16 columns of macro-pixels. At this time, 2 rows x 16 columns of macro-pixels can be actuated for scanning, and 4 rows x 8 columns of macro-pixels can be actuated for scanning.

[0043] It can be understood that the number of times of copying is not strictly limited, and the pixel resolution of the collector can be determined according to the number of times of copying, for example Figure 5 The pixel resolution after copying 4 times in the embodiment is 16*16, and the pixel resolution after copying n times is n*16. More preferably, when a higher pixel resolution of the collector is required, the pixel array 120 as a whole can also be copied, for example, copying once forms a pixel array of 16 rows x 32 columns, that is, the pixel array includes two pixel arrays 120, and the pixel resolution of the collector is expanded to one time of the original. By analogy, copying n times expands to n times of the original.

[0044] In the embodiments of the present application, on the one hand, the same shared TDC circuit can be connected between the macro-pixels, thereby reducing the number of TDC circuits. The macro-pixels connected with different shared TDC circuits can be started at the same time. Since the pixel array 120 includes at least two sub-pixel arrays each composed of m rows x n columns of macro-pixels, all the macro-pixels in any one of the sub-pixel arrays can be controlled to be started. Starting all the macro-pixels in one of the sub-pixel arrays is one scanning mode. Therefore, the distance measuring system is compatible with multiple scanning modes.

[0045] In combination with the embodiment shown in Figures 3 to 5 The present application also provides a method for manufacturing the collector 12, comprising:

[0046] The k shared TDC circuits are provided; two sub-pixel arrays each composed of m rows and n columns of macro-pixels are configured according to the k shared TDC circuits, wherein the product of n and m is k; each macro-pixel in any one of the sub-pixel arrays is connected to a different shared TDC circuit; and a plurality of sub-pixel arrays are configured to form a pixel array.

[0047] Specifically, the k shared TDC circuits are connected to all macro-pixels of the pixel array 120 of the collector 12, wherein each macro-pixel includes one or more pixels, the pixel array 120 includes at least two sub-pixel arrays each composed of m rows and n columns of macro-pixels, each macro-pixel in any one of the sub-pixel arrays of the pixel array 120 is connected to a different shared TDC circuit, and all macro-pixels of the pixel array 120 share the k shared TDC circuits, wherein n and m are both positive integers greater than or equal to 1, and the product of n and m is k.

[0048] Some specific configurations of the distance measuring system are described below.

[0049] Specifically, the transmitter 11 can include a light source array 110 composed of a plurality of light emitting elements, the light source array 110 can be used to emit a laser beam, which can refer to a pulsed light beam. At least part of the pulsed light beam is reflected by the target to form reflected light incident on the pixel array 120 of the collector 12. The aforementioned pixel array 120 is used to collect photons in the reflected light and output a photon signal. The control and processing circuit can control the light source array 110 and the pixel array 120, thereby synchronously controlling the transmitter 11 and the collector 12. Based on the trigger signal of the light source array 110 and the trigger signal of the pixel array 120, the distance measuring system can calculate the time of flight Δt between the emission of the laser beam from the transmitter 11 and the collection of the reflected light by the collector 12, i.e., the time of flight Δt required for the photon to be emitted and received. At this time, the distance d between the target and the distance measuring system can be estimated as d = (c x Δt) / 2, wherein c represents the speed of light.

[0050] The transmitter 11, collector 12, and control and processing circuit in the ranging system are described in detail below. In some embodiments of the present application, the transmitter 11 may include components such as a light source array 110, an emitting optical element, and a driver. The light source array 110 may be a vertical cavity surface emitting laser (VCSEL) array. Specifically, the light source array 110 may be a VCSEL array light source chip that generates multiple VCSEL light sources on a single semiconductor substrate. In some embodiments, the emitting optical element may include one or more of a diffractive optical element (DOE), a lens, a reflector, a galvanometer, and a microlens array. Under the control of the control and processing circuit, the light source array 110 may emit a pulsed light beam at a certain frequency (pulse period). The pulsed light beam is emitted through the lens and ultimately projects onto the target scene to form an illumination spot. The frequency can be set according to the measured distance. Preferably, the emitting optical element can be configured to include a lens with distortion, i.e., an anamorphic lens. In this case, the emission field angle of the light beam emitted by the light source array after passing through the anamorphic lens is greater than the emission field angle without the anamorphic lens.

[0051] The collector 12 may include components such as a pixel array 120, a pixel driving circuit, a filtering unit, and a receiving optical element. The pixel array 120 may include multiple macropixels that collect photons. Each macropixel may include one or more pixels, and each pixel may be a single-photon device that collects photons, such as a SPAD or a silicon photomultiplier (SiPM). Specifically, the pixel array 120 may be composed of multiple SPADs, which may respond to incident single photons and output a photon signal indicating the corresponding arrival time of the received photon at each SPAD. Objects within the target scene reflect the laser light leaving the transmitter 11, forming reflected light that is incident on the collector 12. The reflected light entering the collector 12 passes through the receiving optical element and is incident on the pixel array 120 to form reflected light. The fact that a working pixel on the pixel array 120 collects a photon is considered a photon detection event and outputs a photon signal. Preferably, the receiving optical element may be configured to include a lens with distortion, i.e., an anamorphic lens. In this case, the collector's field of view is greater than when the anamorphic lens is not included.

[0052] The ranging system can further include a readout circuit coupled to the pixel array 120, which can include one or more of a signal amplifier, a time-to-digital converter circuit (TDC circuit), an analog to digital converter (ADC), a memory, a histogram circuit, etc. In embodiments of the present application, the readout circuit can be integrated with the pixel array 120 as part of the collector 12. The readout circuit can be configured to acquire and process the photon signals from the working pixels coupled to the pixel array 120 to determine the time-of-flight At between the emission of the laser light from the emitter 11 and the collection of the reflected light by the collector 12.

[0053] In one embodiment, upon receiving the photon signals from the working pixels, the TDC circuit can determine the time-of-flight At based on the photon signals and send an update signal to the histogram circuit to instruct the histogram circuit to generate or update a histogram for recording the time-of-flight. For example, the TDC circuit can generate a time code representing the time-of-flight information, find a corresponding location in the histogram in the histogram circuit using the time code, and cause the storage unit at the corresponding location in the histogram circuit to store a value of “1”. Each storage unit can be a time bin. After a number of cycles of time-of-flight measurement, the histogram can be read out from the histogram circuit, which contains the time-of-flight of the laser light beam from emission to collection.

[0054] The control and processing circuit is coupled to the emitter and the collector, receives the histogram and processes the histogram to calculate the time-of-flight of the laser light beam from emission to collection, and calculates the distance of the target based on the time-of-flight.

[0055] It should be noted that, as shown in Figure 6 The ranging system can include a distortion lens in the emitter 11 and / or the collector 12, which is configured to distort the light beam incident to the lens to change the FOV of the outgoing light beam. The type of distortion generated by the distortion lens can be selected according to the actual situation, and the lens distortion configured by the distortion lens located on the emitter 11 and the collector 12 can be negative distortion (also known as barrel distortion).

[0056] In some embodiments of the present application, the distortion lens can only be provided in the emitter 11, in which case the spot pattern projected by the light source array 110 in the field of view is distorted, and the laser light beam emitted from the emitter has a first field of view larger than a second field of view, both of which refer to the projection FOV. The second field of view refers to the field of view of the laser light emitted from the emitter when the emitter does not include a distortion lens, which can be the FOV of the laser light beam directly projected, or the FOV of the light beam projected after passing through a lens without distortion. Please refer to Figure 7 , Figure 7The light spot distribution diagram of the laser projection on the wall surface is shown, the projection FOV (71) is expanded after the distortion lens, and the receiving FOV (72) of the collector 12 is fixed in the region of interest. The edge light spot (such as the light spot 73) outside the receiving FOV can not be sampled, and therefore the light emitting element corresponding to the edge light spot can be controlled to be turned off. At this time, the collector 12 is not provided with a distortion lens, and the emitter 11 is provided with a distortion lens. In this case, the chip target surface area (the area of the light source array 110) of the emitter 11 can be reduced, and the chip target surface area (the area of the pixel array 120) of the collector 12 can be increased, so that the edge light spot is sampled, and the detection field of view range is increased by increasing the receiving FOV.

[0057] In other embodiments, only the collector 12 can be provided with a distortion lens. In this case, the reflected light in the third field of view will enter the collector 12, wherein the third field of view is greater than the fourth field of view, and the third field of view and the fourth field of view both refer to the projection FOV. Specifically, the fourth field of view is the collection field of view corresponding to the collector 12 without the distortion lens, and the third field of view is the collection field of view corresponding to the collector 12 with the distortion lens. As shown in the figure, the negative distortion will expand the receiving FOV (81) without changing the focal length of the lens. At this time, in order to make the projection FOV of the emitter 11 the same as the receiving FOV, the chip target surface area of the emitter 11 can be greater than the chip target surface area of the collector 12. Figure 8

[0058] In another embodiment, the emitter 11 and the collector 12 can both be provided with a lens distortion. Compared with the case without the distortion lens, the projection FOV and the receiving FOV are both increased. The FOV is expanded by using the lens distortion, and therefore the chip target surface area of the emitter 11 and the chip target surface area of the collector 12 can be reduced. The distortion coefficients of the distortion lenses located on the emitter 11 and the collector 12 can be consistent, and the focal lengths of the emitter 11 and the collector 12 can be different. The specific values can be set according to the actual situation, and the application does not limit this.

[0059] In some embodiments, the chip target surface area of the emitter 11 can be smaller than the chip target surface area of the collector 12. In combination with the distortion lens, the cost of the emitter 11 can be reduced while keeping the FOV size unchanged.

[0060] It can be understood that the lenses need to be provided in the emitter 11 and the collector 12 to modulate the light beams, and the corresponding emission field of view and collection field of view are affected by the area of the light source array and the pixel array and the focal length of the lens. The embodiments of the application can change the emission field of view angle and the collection field of view angle by adding distortion to the lens without changing these factors, which is simple and efficient.

[0061] ​In some embodiments of the present application, the light source array 110 described above comprises a plurality of sub-arrays; the control and processing circuit can be used to control any one sub-array to emit a laser beam, which can include a plurality of light emitting elements, each corresponding to a macro-pixel; accordingly, the control and processing circuit can synchronously control the j working pixels in the collector 12 corresponding to the light emitting elements to collect the laser beam to realize sequential scanning such as row scanning and column scanning. Specifically, the control and processing circuit can be used to send a third trigger signal to the emitter 11 to control any one sub-array of the light source array 110 to emit a laser beam. Moreover, the control and processing circuit can control the light source array 110 to emit laser beams from a plurality of light emitting elements far away at the same time while keeping the number of light emitting elements turned on unchanged, thereby reducing the light emitting element opening integration to reduce the heat integration generated during light emission and increase the service life of the emitter 11.

[0062] For example, referring to the light source array 110 shown in Figure 9 , the original sub-array (a total of 10x12 light emitting elements) composed of light emitting elements in the 1# and 2# regions needs to emit light, and now the sub-array (10x6 light emitting elements respectively) composed of light emitting elements in the 1# and K# regions can be controlled to emit light. At this time, the heat energy will not be concentrated in the region composed of 1# and 2#, which can effectively increase the service life of the emitter 11, and since the number of light emitting elements opened is the same, the resolution of the ranging system will not be affected.

[0063] In some embodiments of the present application, the pixel array 120 described above can include a plurality of pixels, each sub-array of the light source array 110 is associated with a gating region, each gating region contains at least one macro-pixel, and the macro-pixels in the gating region are respectively connected to different shared TDC circuits, and preferably each gating region corresponds to a sub-pixel array. Specifically, the number of light emitting elements in the sub-array corresponds to the number of macro-pixels in the gating region, and preferably considering the parallax existing in the ranging system itself, the number of macro-pixels is greater than the number of light emitting elements. After the control and processing circuit controls a certain sub-array to emit a laser beam, it can also be used to send a second trigger signal to the collector 12 to control all macro-pixels in the gating region associated with the sub-array emitting the laser beam to be turned on, so that the turned-on macro-pixels collect the reflected light signal.

[0064] In the ranging system, according to the TCSPC detection principle, one ranging of the target often needs the transmitter 11 to continuously emit a plurality of pulsed light beams, i.e. a pulse sequence, and the adjacent pulses have the same pulse period. In order to further reduce the thermal integration, the control and processing circuit can also be used to send a first trigger signal to the transmitter 11 to control the transmitter to emit the pulse sequence, the first trigger signal is a modulated signal, and the modulated pulse sequence can contain p groups of pulses, each group of pulses contains at least one pulse, and the time interval between adjacent two groups of pulses is the same or different, so as to control the light source array 110 to intermittently emit the laser light beam according to the modulated signal.

[0065] Figure 10 The timing diagram of the light source array 110 firing (emitting a laser light beam) is shown, wherein each rectangular column can represent one pulse, i.e. emitting a laser light beam. Based on the first trigger signal, the light source array 110 can continue to emit pulses after a few cycles of rest after continuously emitting a few laser light beams, so that the thermal energy is reduced in the rest period, and the thermal integration is reduced. For example, the time interval between the adjacent two times of continuously emitting the initial laser light can be 400 ns, and the rest period can be m times of 400 ns, and m is greater than 1.

[0066] In the embodiments of the present application, another ranging system is also provided, which is different from the ranging system shown in the foregoing in that the readout circuit (including the TDC circuit) can also be part of the control and processing circuit.

[0067] Specifically, the ranging system can include a transmitter 11, a collector 12, and a control and processing circuit; the collector 12 includes a pixel array 120 composed of a plurality of macro-pixels, the pixel array 120 contains at least two sub-pixel arrays, each sub-pixel array includes m rows × n columns of macro-pixels, and each macro-pixel includes one or more pixels. The control and processing circuit includes a preset k shared TDC circuit, wherein the number of macro-pixels is at least s times the number of shared TDC circuits, each macro-pixel in each sub-pixel array is connected to a different shared TDC circuit, so that at least two macro-pixels in the pixel array are connected to one shared TDC circuit; wherein s is a positive integer greater than 1, n and m are positive integers greater than or equal to 1, and the product of n and m is k.

[0068] In addition, the ranging system can further include a pixel driving circuit connected with the pixel array 120, configured to control the j macro-pixels in the pixel array 120 to be turned on simultaneously, so as to take the macro-pixels turned on simultaneously as working pixels. The j working pixels can be used to collect reflected light to generate a photon signal, wherein the j working pixels are respectively connected with different macro-pixels of the shared TDC circuit. The control and processing circuit can be configured to process the photon signal of the corresponding working pixel through the shared TDC circuit connected with the j working pixels, so as to realize ranging based on the photon signal.

[0069] It should be understood that the readout circuits (including the TDC circuit) of the two ranging systems are located in different positions, but have the same implementation and working principle, and the detailed description can refer to the description of the other ranging system, which will not be described herein.

[0070] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A collector, characterized in that: include: k shared TDC circuits, where k is a positive integer greater than 1; a pixel array, the pixel array comprising a plurality of macropixels, the number of the macropixels being at least s times the number of the shared TDC circuits, each of the macropixels comprising one or more pixels, and the pixels constituting one macropixel being configured to be activated simultaneously to receive the same light spot; The pixel array is configured to include at least two sub-pixel arrays, each sub-pixel array includes m rows×n columns of the macropixels, and m or n are different for different sub-pixel arrays; each macropixel in each sub-pixel array is connected to a different shared TDC circuit, so that at least two macropixels in the pixel array are connected to one shared TDC circuit in common; Wherein, s is a positive integer greater than 1, n and m are both positive integers greater than or equal to 1, and the product of n and m is k.

2. The collector according to claim 1, wherein: configuring j macro-pixels in the pixel array to be simultaneously turned on as working pixels to collect reflected light to generate photon signals, wherein the j working pixels are respectively connected to different shared TDC circuits; The shared TDC circuits respectively connected to the j working pixels are used to process the photon signals of the corresponding working pixels.

3. The collector according to claim 2, characterized in that: The collector further includes a histogram circuit connected to the shared TDC circuit; The shared TDC circuit receives the photon signal of the corresponding working pixel, determines the flight time from the laser emission from the emitter to the reflected light collected by the collector, and sends an update signal to the histogram circuit to instruct the histogram circuit to generate or update a histogram for recording the flight time.

4. The collector according to claim 2, characterized in that: The collector further includes a pixel driving circuit connected to the pixel array; The pixel driving circuit is used to control j macro-pixels in the pixel array to be turned on simultaneously, so that the macro-pixels turned on simultaneously serve as the working pixels.

5. A ranging system, characterized in that: include: A transmitter, a collector according to any one of claims 1 to 4, and a control and processing circuit connected to the transmitter and the collector; The transmitter includes a light source array composed of a plurality of light-emitting elements for emitting a laser beam toward a target; The collector is used to collect the laser beam reflected by the target; The control and processing circuit is used to synchronously control the emitter and the collector, and calculate the flight time of the laser beam from emission to collection to obtain the distance of the target.

6. The distance measurement system according to claim 5, wherein: The light source array includes a plurality of sub-arrays; The control and processing circuit is used to control any one of the sub-arrays to emit the laser beam; and synchronously control j working pixels in the collector to collect the laser beam.

7. The distance measurement system according to claim 6, wherein: The control and processing circuit is further configured to send a first trigger signal to the transmitter to control the transmitter to transmit a pulse sequence, wherein the pulse sequence comprises p groups of pulses, each group of pulses comprises at least one pulse, and the time intervals between two adjacent groups of pulses are the same or different.

8. The distance measurement system according to any one of claims 5 to 7, wherein: The emitter and / or the collector comprises a distorting lens; Wherein, when the transmitter includes the distorting lens, the transmitting field angle of the transmitter is greater than the transmitting field angle when the distorting lens is not included; When the collector includes a distortion lens, the collection field angle of the collector is greater than the collection field angle when the collector does not include the distortion lens.

9. A ranging system, characterized in that: Including transmitter, collector, and control and processing circuits; The transmitter includes a light source array composed of a plurality of light-emitting elements for emitting a laser beam toward a target; The collector includes a pixel array composed of a plurality of macro pixels, the pixel array is configured to include at least two types of sub-pixel arrays, each of the sub-pixel arrays includes m rows×n columns of the macro pixels, and different types of sub-pixel arrays have different m or n; each macro pixel includes one or more pixels, and the pixels constituting a macro pixel are configured to be activated simultaneously to receive the same light spot; The control and processing circuit includes k shared TDC circuits; The number of the macropixels is at least s times the number of the shared TDC circuits, and each of the macropixels in the subpixel array is connected to a different shared TDC circuit, so that at least two macropixels in the pixel array are connected to one shared TDC circuit. Wherein, s and k are both positive integers greater than 1, n and m are both positive integers greater than or equal to 1, and the product of n and m is k.

10. A method for manufacturing a collector, characterized in that: include: Providing k shared TDC circuits, where k is a positive integer greater than 1; Two sub-pixel arrays consisting of m rows and n columns of macropixels are configured according to the k shared TDC circuits, where m or n are different in different sub-pixel arrays; the number of macropixels is at least s times the number of shared TDC circuits, each macropixel includes one or more pixels, and the pixels constituting one macropixel are configured to be activated simultaneously to receive the same light spot, wherein s is a positive integer greater than 1, n and m are both positive integers greater than or equal to 1, and the product of n and m is k; Setting each of the macro pixels in any one of the sub-pixel arrays to be connected to a different shared TDC circuit; A plurality of the sub-pixel arrays are arranged to form a pixel array.

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