Time-of-flight ranging sensor, control module and method thereof, and electronic device

Abstract

The present application provides a time-of-flight ranging sensor and its control module and method, and electronic device. The time-of-flight ranging sensor includes a transmitting module, a receiving module, and a processing module. The transmitting module transmits multiple detection light signals to the measurement scene according to a preset time sequence within a partition detection period. The partition detection period is divided into multiple sensing periods corresponding to the detection light signals. The receiving module works in coordination according to the sensing period to sense the light signal from the measurement scene. The processing module is used to process and analyze the light sensing signal to obtain the distance information of the external object. For at least one sensing period in the partition detection period, the control module controls the start of the receiving module at a first time and the start of the transmitting module at a second time, and the second time is later than the first time. By turning on the receiving module first and then the transmitting module in at least one sensing period of the partition detection period, the influence of the pile-up effect caused by the ambient light on the ranging accuracy is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of light detection technology, and specifically to a time-of-flight ranging sensor, a control module and method thereof, and an electronic device. Background Art

[0002] At present, direct time-of-flight (dToF) is a distance measurement method that uses time-correlated single-photon counting (TCSPC) technology to measure the distance of objects in the scene. The working principle of dToF technology is simple, with a long effective detection distance, high accuracy and low energy consumption. Compared with traditional structured light and binocular stereo vision distance measurement methods, dToF has more obvious advantages, with small calculation amount of depth (ie distance) information, strong anti-interference ability and long measurement range. Time-of-flight ranging sensors, systems and lidars based on dToF technology can be applied to multiple products such as mobile phones, sweeping robots, drones, automobiles, etc., serving machine vision, autonomous driving, monitoring and identification, remote sensing mapping and AR / VR and other fields.

[0003] Since the time-of-flight ranging sensor receives ambient light while receiving the detection light signal, when the ambient light intensity is high, the probability of the photosensitive device sensing the detection light signal reflected by the target object will be reduced, thereby affecting the accuracy of the ranging. Therefore, there is a technical problem in the prior art that the ranging accuracy is easily affected by the ambient light. Summary of the invention

[0004] In view of this, multiple embodiments of the present application are directed to providing a time-of-flight ranging sensor and a control module and method thereof, and an electronic device to reduce the impact of ambient light on ranging accuracy.

[0005] According to a first aspect of the present invention, multiple embodiments of the present application provide a control module for a time-of-flight ranging sensor, the time-of-flight ranging sensor comprising a transmitting module, a receiving module and a processing module, the transmitting module transmitting a plurality of detection light signals to a measurement scene in a preset time sequence within a partition detection period, the partition detection period being divided into a plurality of sensing periods corresponding to the detection light signals, the receiving module working in coordination with the sensing periods to sense light signals from the measurement scene, the processing module being used to process and analyze light sensing signals generated corresponding to the light signals received by the receiving module to obtain a moment when the detection light signal echo is sensed by the receiving module, and to obtain distance information of an external object according to a time difference between the emission moment of the detection light signal and the moment when the reflected light signal is sensed;

[0006] Among them, for at least one sensing period in the partition detection period, the control module controls to turn on the receiving module at a first time, and controls to turn on the transmitting module at a second time, and the second time is later than the first time.

[0007] According to a second aspect of the present invention, multiple embodiments of the present application provide a time-of-flight ranging sensor, which is configured to sense external objects in a measurement scene based on the time-of-flight principle to obtain distance information of the external objects. The time-of-flight ranging sensor includes:

[0008] The transmitting module is configured to transmit a plurality of detection light signals to the measurement scene according to a preset time sequence within a partition detection period, wherein the partition detection period is divided into a plurality of sensing periods corresponding to the detection light signals;

[0009] A receiving module is configured to work together according to the sensing period to sense the optical signal from the measurement scene

[0010] a processing module configured to process and analyze the light sensing signal generated by the receiving module in response to the light signal received by the receiving module to obtain the time when the detection light signal echo is sensed by the receiving module, and obtain the distance information of the external object according to the time difference between the emission time of the detection light signal and the time when the reflection is sensed; and

[0011] Control module as previously described.

[0012] According to a third aspect of the present invention, multiple embodiments in the present application provide an electronic device, comprising: a processor, a memory and the above-mentioned time-of-flight ranging sensor, the time-of-flight ranging sensor and the memory are respectively connected to the processor, and the processor is configured to control the electronic device according to the distance information obtained by the time-of-flight ranging sensor.

[0013] According to a fourth aspect of the present invention, multiple embodiments of the present application provide a control method for a time-of-flight ranging sensor, the time-of-flight ranging sensor comprising a transmitting module and a receiving module, the transmitting module transmitting a plurality of detection light signals in a preset time sequence within a partitioned detection period, the partitioned detection period being divided into a plurality of sensing periods corresponding to the detection light signals, the receiving module working in coordination with the sensing periods to sense light signals from a measurement scene and output corresponding light sensing signals; for at least one sensing period in a partitioned detection period, the control method comprising: at a first time, turning on the receiving module of the time-of-flight ranging sensor; at a second time, turning on the transmitting module of the time-of-flight ranging sensor; wherein the second time is later than the first time.

[0014] In the multiple embodiments provided in the present application, in at least one sensing period of the partitioned detection period, the interference of ambient light on sensing is reduced by turning on the receiving module before turning on the transmitting module, thereby improving the ranging accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the circuit structure of an electronic device provided in an embodiment of the present application.

[0016] Figure 2 This is a schematic block diagram of the functional modules of the time-of-flight ranging sensor provided in an embodiment of the present application.

[0017] Figure 3 A statistical histogram of photon counts caused by ambient light provided in an embodiment of the present application.

[0018] Figure 4 A statistical histogram of photon counts generated by ambient light and detection light signals when the transmitting module and the receiving module of the time-of-flight ranging sensor provided in an embodiment of the present application are turned on synchronously, wherein a pile-up effect exists.

[0019] Figure 5 The time-of-flight ranging sensor provided in the embodiment of the present application obtains a statistical histogram of photon counts generated only by ambient light when only the receiving module is turned on, wherein a stable noise background has been formed.

[0020] Figure 6 A photon counting statistical histogram generated by the ambient light and the detection light signal when the transmitting module and the receiving module of the time-of-flight ranging sensor provided in an embodiment of the present application are asynchronously turned on.

[0021] Figure 7 This is a flow chart of a control method of a time-of-flight ranging sensor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a single-photon avalanche diode, a preparation method, a photoelectric detection device and an electronic device proposed according to the present invention are described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] The aforementioned and other technical contents, features and effects of the present invention are clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. However, the attached drawings are only for reference and illustration purposes and are not used to limit the technical solutions of the present invention.

[0024] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the statement "including one..." do not exclude the existence of other identical elements in the article or device including the elements.

[0025] An embodiment of the present application provides a control module for a time-of-flight ranging sensor, the time-of-flight ranging sensor comprising a transmitting module, a receiving module and a processing module, the transmitting module transmitting a plurality of detection light signals to a measurement scene in a preset time sequence within a partition detection period, the partition detection period being divided into a plurality of sensing periods corresponding to the detection light signals, the receiving module working in coordination with the sensing periods to sense light signals from the measurement scene, the processing module being used to process and analyze light sensing signals generated corresponding to the light signals received by the receiving module to obtain the moment when the detection light signal echo is sensed by the receiving module, and obtaining distance information of an external object according to the time difference between the emission moment of the detection light signal and the moment when the reflected light signal is sensed;

[0026] Among them, for at least one sensing period in the partition detection period, the control module controls to turn on the receiving module at a first time, and controls to turn on the transmitting module at a second time, and the second time is later than the first time.

[0027] In some embodiments, the control module determines the delay duration of the second time compared to the first time based on the ambient light intensity of the measured scene; wherein the delay duration of the second time compared to the first time may be positively correlated with the ambient light intensity.

[0028] In some embodiments, the time-of-flight ranging sensor further includes a light intensity sensor, and the control module acquires the ambient light intensity of the measurement scene through the light intensity sensor.

[0029] In some embodiments, the control module is configured to control the receiving module to be turned on separately for a preset period of time before starting a partition detection period, and determine the ambient light intensity of the measurement scene according to the count value of the light sensing signal accumulated by the receiving module during this period.

[0030] In some embodiments, the receiving module includes a single photon avalanche diode for sensing optical signals, and the delay time may be a specified multiple of the dead time of the single photon avalanche diode.

[0031] In some embodiments, the control module is configured to control the receiving module to remain turned on after being turned on at the first time in the first sensing period of the partition detection period until the partition detection period ends.

[0032] In some embodiments, the control module is configured to control the processing module to obtain the distance information based on processing and analysis of the light sensing signal generated after the emission module starts to emit the detection light signal within the sensing period.

[0033] An embodiment of the present application further provides a time-of-flight sensor, which is configured to sense an external object in a measurement scene based on the time-of-flight principle to obtain distance information of the external object. The time-of-flight ranging sensor includes:

[0034] The transmitting module is configured to transmit a plurality of detection light signals to the measurement scene according to a preset time sequence within a partition detection period, wherein the partition detection period is divided into a plurality of sensing periods corresponding to the detection light signals;

[0035] A receiving module is configured to work together according to the sensing period to sense the optical signal from the measurement scene

[0036] a processing module configured to process and analyze the light sensing signal generated corresponding to the light signal received by the receiving module to obtain the moment when the detection light signal echo is sensed by the receiving module, and to obtain the distance information of the external object based on the time difference between the emission moment of the detection light signal and the moment when the reflection is sensed; and the control module as described above.

[0037] An embodiment of the present application further provides an electronic device, comprising: a processor, a memory, and the time-of-flight ranging sensor as described above. The time-of-flight ranging sensor and the memory are respectively connected to the processor, and the processor is configured to control the electronic device according to the distance information obtained by the time-of-flight ranging sensor.

[0038] The embodiment of the present application also provides a control method for a time-of-flight ranging sensor, the time-of-flight ranging sensor comprising a transmitting module and a receiving module, the transmitting module transmitting a plurality of detection light signals in a partition detection period according to a preset time sequence, the partition detection period being divided into a plurality of sensing periods corresponding to the detection light signals, the receiving module working in coordination with the sensing periods to sense light signals from a measurement scene and output corresponding light sensing signals; for at least one sensing period in a partition detection period. The control method comprises:

[0039] At the first opportunity, start the receiving module;

[0040] At a second time, the transmitting module is turned on; wherein the second time is later than the first time.

[0041] like Figure 1 As shown, the electronic device 200 described in the electronic device embodiment of the present application may be an electronic device 200 with a ToF (Time of Flight, ToF) function, which may be used for three-dimensional information sensing or spatial distance measurement, for example, it may be used for face recognition, gesture recognition, posture or action recognition, automatic driving, machine vision, building recognition, scene recognition modeling, augmented reality (AR) / virtual reality (VR), ranging, proximity sensing, simultaneous localization and mapping (SLAM), or 3D mapping, etc. The electronic device 200 may include a smart phone, a tablet computer, a computer, a laptop computer, a desktop computer, a smart wearable device, a smart door lock, an in-vehicle electronic device, medical, aviation, automobile, unmanned vehicle, and other devices or apparatuses that require a three-dimensional information sensing function.

[0042] The electronic device 200 can be a device based on the principle of direct time of flight (dToF) or indirect time of flight (iToF). Among them, dToF technology is a distance measurement method based on time-correlated single photon counting (TCSPC) to measure the distance of objects in the scene. TCSPC can perform statistical analysis on the time information of photon events (such as the process from emission to reception of a single photon) by repeatedly emitting and receiving detection light signals to obtain relevant three-dimensional information of the target object that reflects the detection light signal.

[0043] An exemplary structure of the electronic device 200 is described below: Figure 1 As shown, the electronic device 200 may include a processor 210 and a memory 220 , and the processor 210 is connected to the memory 220 .

[0044] The processor 210 can be used to control the operation of the electronic device 200, and the processor 210 can also be called a central processing unit (CPU). The processor 210 can be an integrated circuit chip with signal processing capabilities. The processor 210 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an image processor (ISP), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The general-purpose processor can be a microprocessor or the processor 210 can also be any conventional processor, etc.

[0045] The memory 220 can be used to store computer programs, such as a random access memory (RAM), a read-only memory (ROM), or other types of storage devices. Specifically, the memory 220 may include one or more computer-readable storage media, which may be non-transitory. In some embodiments, the non-transitory computer-readable storage medium in the memory 220 is used to store at least one program code. The computer program stored in the memory 220 can be executed by the processor 210, and then the operation of the electronic device 200 can be controlled to realize related operations and functions.

[0046] Of course, the read-only memory (ROM) can be, for example, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The random access memory (RAM) is used as an external cache, and can be, for example, a static random access memory (SRAM), a dynamic random access memory (DRAM), a synchronous dynamic random access memory (SDRAM), a double data rate synchronous dynamic random access memory (DDR SDRAM), an enhanced synchronous dynamic random access memory (ESDRAM), a synchronous link dynamic random access memory (SLDRAM), and a direct RAM bus random access memory (DRRAM).

[0047] In some embodiments, the electronic device 200 may further include: a peripheral device interface 230 and at least one peripheral device. The processor 210, the memory 220 and the peripheral device interface 230 may be connected via a bus or a signal line. Each peripheral device may be connected to the peripheral device interface 230 via a bus, a signal line or a circuit board. Specifically, the peripheral device may include: one or more of a radio frequency circuit 240, a display screen 250, an audio circuit 260 and a power supply 270.

[0048] The peripheral device interface 230 may be used to connect at least one peripheral device related to I / O (Input / output) to the processor 210 and the memory 220. In some embodiments, the processor 210, the memory 220, and the peripheral device interface 230 may be integrated on the same chip or circuit board. In some other embodiments, any one or two of the processor 210, the memory 220, and the peripheral device interface 230 may be implemented on a separate chip or circuit board, which is not limited in this embodiment.

[0049] The radio frequency circuit 240 is used to receive and transmit radio frequency (RF) signals, also known as electromagnetic signals. The radio frequency circuit 240 communicates with the communication network and other communication devices through electromagnetic signals. The radio frequency circuit 240 converts electrical signals into electromagnetic signals for transmission, or converts received electromagnetic signals into electrical signals. Optionally, the radio frequency circuit 240 includes: an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a user identity module card, and the like. The radio frequency circuit 240 can communicate with other terminals through at least one wireless communication protocol. The wireless communication protocol includes, but is not limited to: the World Wide Web, a metropolitan area network, an intranet, various generations of mobile communication networks (2G, 3G, 4G and 5G), a wireless local area network and / or a wireless fidelity (Wireless Fidelity, Wi-Fi) network. In some embodiments, the radio frequency circuit 240 may also include circuits related to near field communication (NFC), which is not limited in this application.

[0050] The display screen 250 is used to display a user interface (UI). The user interface may include graphics, text, icons, videos, and any combination thereof. When the display screen 250 is a touch display screen, the display screen 250 also has the ability to collect touch signals on the surface or above the surface of the display screen 250. The touch signal may be input as a control signal to the processor 210 for processing. At this time, the display screen 250 may also be used to provide virtual buttons and / or virtual keyboards, also known as soft buttons and / or soft keyboards. In some embodiments, the display screen 250 may be one, arranged on the front panel of the electronic device 200. In other embodiments, the display screen 250 may be at least two, arranged on different surfaces of the electronic device 200 or in a folding design; in other embodiments, the display screen 250 may be a flexible display screen, arranged on a curved surface or a folding surface of the electronic device 200. Even, the display screen 250 may also be arranged in a non-rectangular irregular shape, i.e., a special-shaped screen. The display screen 250 may be prepared using materials such as a liquid crystal display (LCD), an organic light-emitting diode (OLED), and the like.

[0051] The audio circuit 260 may include a microphone and a speaker. The microphone is used to collect sound waves from the user and the environment, and convert the sound waves into electrical signals and input them into the processor 210 for processing, or input them into the radio frequency circuit 240 to achieve voice communication. For the purpose of stereo acquisition or noise reduction, there may be multiple microphones, which are respectively arranged at different parts of the electronic device 200. The microphone may also be an array microphone or an omnidirectional acquisition microphone. The speaker is used to convert the electrical signal from the processor 210 or the radio frequency circuit 240 into sound waves. The speaker may be a traditional film speaker or a piezoelectric ceramic speaker. When the speaker is a piezoelectric ceramic speaker, it can not only convert the electrical signal into sound waves audible to humans, but also convert the electrical signal into sound waves inaudible to humans for purposes such as ranging. In some embodiments, the audio circuit 260 may also include a headphone jack.

[0052] The power supply 270 is used to power various components in the electronic device 200. The power supply 270 can be an alternating current, a direct current, a disposable battery, or a rechargeable battery. When the power supply 270 includes a rechargeable battery, the rechargeable battery can be a wired rechargeable battery or a wireless rechargeable battery. A wired rechargeable battery is a battery that is charged through a wired line, and a wireless rechargeable battery is a battery that is charged through a wireless coil. The rechargeable battery can also be used to support fast charging technology.

[0053] The electronic device 200 may further include a time-of-flight ranging sensor 100. In some embodiments, the time-of-flight ranging sensor 100 may be used to implement a dToF function, sensing an external object in a measurement scene to obtain three-dimensional information of the external object.

[0054] like Figure 2 As shown, the time-of-flight ranging sensor 100 may include a transmitting module 110 , a receiving module 120 , a processing module 130 and a memory 140 .

[0055] The transmitting module 110 can be used to transmit a detection light signal to the measurement scene, part of which will be reflected by external objects in the measurement scene and returned, and the reflected detection light signal carries the three-dimensional information of the external objects in the measured scene. In some embodiments, the detection light signal can be, for example, a plurality of laser pulses emitted in sequence. The transmitting module 110 can transmit detection light signals to partitions of different orientations in the measurement scene in a time-sharing manner according to a preset scanning method for distance detection, and transmit N detection light signals to each partition according to a corresponding preset time sequence, where N is a positive integer. After completing the emission of N detection light signals to one of the partitions, the distance information of the partition can be obtained accordingly. This process can be regarded as a partition detection period, and scanning multiple partitions one by one is regarded as completing a frame of detection of the entire measurement scene, and the distance information of all partitions of the entire measurement scene can be obtained accordingly, which can be used to construct a point cloud of a frame of the entire measurement scene. That is, one frame detection of the measurement scene includes multiple partition detection periods corresponding to the partition scanning. A partition detection period can be divided into multiple sensing periods corresponding to the emission of each detection light signal. For example, if N detection light signals are emitted in a partition detection period, then a partition detection period includes N sensing periods, and each sensing period corresponds to an emission cycle of a detection light signal. It can be understood that the emission module 110 can be integrated inside the time-of-flight ranging sensor 100 or can be external. The emission module 110 can include a driving circuit 111, a light source 112, and an emission optical device 113.

[0056] The receiving module 120 can work together according to the sensing period to sense the light signal from the measurement scene and output a corresponding light sensing signal. It is understood that the light signal received by the receiving module 120 can include ambient light in the measurement scene and / or a detection light signal reflected by an external object in the measurement scene.

[0057] The receiving module 120 may include a photoelectric sensor 122 and a receiving optical device 121. Optionally, the photoelectric sensor 122 may include a single photosensitive pixel or a plurality of photosensitive pixels. A plurality of photosensitive pixels may be arranged in a pixel array. The photosensitive pixel is used to receive a light signal from a measurement scene and output a corresponding light sensing signal. The photosensitive pixel includes at least one photosensitive device. Optionally, the photosensitive device is, for example, an avalanche photodiode (APD), a single photon avalanche diode (SPAD), a silicon photomultiplier (SiPM) in which a plurality of SPADs are arranged in parallel, and / or other suitable photosensitive devices. Optionally, the plurality of photosensitive pixels may not be arranged in an array, for example, they may be arranged in an irregular manner. In the following, the photosensitive device will be introduced as a single photon avalanche diode as an example.

[0058] The processing module 130 can be used to analyze and process the light sensing signal generated corresponding to the light signal received by the receiving module 120 to obtain the time when the detection light signal echo is sensed by the receiving module 120, and obtain the three-dimensional information of the external object according to the time difference between the emission time of the detection light signal and the time when the reflection is sensed. It should be understood that all or part of the functional units of the memory 140 and / or the processing module 130 can be set in the time-of-flight ranging sensor 100, and can also be set on an electronic device equipped with the time-of-flight ranging sensor 100.

[0059] In some embodiments, the processing module 130 may include, for example, functional units such as a counting unit 131 , a statistical unit 132 , a flight time acquisition unit 133 , and a distance acquisition unit 134 .

[0060] The counting unit 131 is used to count in the corresponding time bin according to the time when the receiving module 120 receives the light signal and outputs the light sensing signal. The time bin is the minimum time unit Δt at which the counting unit records the moment when the light sensing signal is generated, which can reflect the accuracy of the time recording of the light sensing signal by the counting unit 131. The finer the time bin, the higher the accuracy of the recorded time.

[0061] Optionally, the counting unit 131 may include a time-to-digital converter (TDC) and a counting memory, wherein the counting memory has a counting storage space allocated according to the time bins. The receiving module 120 outputs a corresponding light sensing signal each time it senses a photon, and the TDC accumulates one in the counting memory of the corresponding time bin according to the generation time of the light sensing signal.

[0062] The statistical unit 132 may be configured to perform statistics on the accumulated light sensing signal counts in each corresponding time bin to generate a corresponding photon counting statistical histogram (eg, Figure 3 As shown). The horizontal axis of the photon counting statistical histogram represents the timestamp of each corresponding time bin, and the vertical axis of the photon counting statistical histogram represents the accumulated light sensing signal count value in each corresponding time bin. Optionally, the statistical unit can be a histogram circuit.

[0063] During the sensing process, a large number of ambient light photons will also be received by the receiving module 120 to generate corresponding light sensing signal counts. Since the probability of leaving counts in each time bin when the ambient light photons are sensed tends to be the same, the noise background (Noise Level) of the measurement scene is formed. In the measurement scene with high ambient light intensity, the average level of the measured noise background is relatively high, and in the scene with low ambient light, the average level of the measured noise background is relatively low. On this basis, the detection light signal reflected from the external object is received and the corresponding light sensing signal count generated is superimposed on the noise background, so that the light sensing signal count in the time bin corresponding to the moment when the detection light signal is received will be significantly higher than the light sensing signal count in other time bins, thereby forming a prominent signal peak. It can be understood that the count height of the signal peak will be affected by factors such as the optical emission power of the detection light signal, the reflectivity of the external object, and the detection range of the time-of-flight ranging sensor 100, and the width of the signal peak will be affected by factors such as the width of the emitted detection light signal, the light sensing device of the receiving module 120, and the time jitter of the TDC. Thus, the flight time acquisition unit 133 can obtain the flight time of the relevant detection light signal reflected by the external object and received by the receiving module 120 according to the time difference between the time stamp of the time bin corresponding to the peak value of the signal peak and the emission time of the relevant detection light signal generating the signal peak. The distance acquisition unit 134 can obtain the distance information between the external object reflecting the relevant detection light signal and the transmitting module 110 according to the flight time of the relevant detection light signal determined by the photon counting statistical histogram. For example, it is to measure the line distance between the external object in the scene and the position on the transmitting module 110 where the relevant detection light signal is emitted.

[0064] It should be understood that the transmitting module 110 and the receiving module 120 are arranged side by side, and the light emitting surface of the transmitting module 110 and the light incident surface of the receiving module 120 are both facing the same side of the time-of-flight ranging sensor 100. The range of the distance between the transmitting module 110 and the receiving module 120 can be, for example, 2 millimeters (mm) to 20 mm. Since the transmitting module 110 and the receiving module 120 are relatively close to each other, although the transmission path of the detection light signal from the transmitting module 110 to the external object and the return path from the external object to the receiving module 120 after reflection are not completely equal, both are much larger than the distance between the transmitting module 110 and the receiving module 120, and can be regarded as approximately equal. Therefore, the distance information between the external object and the time-of-flight ranging sensor 100 can be calculated based on the product of half of the flight time t of the detection light signal reflected back by the external object and the speed of light c.

[0065] A single-photon avalanche diode can be used as a photosensitive device of a photosensitive pixel to sense light signals from the measurement scene. A single-photon avalanche diode can have two states, one is the Geiger state and the other is the quenched state. When the single-photon avalanche diode is in the Geiger state, it can be used to detect photons. The Geiger state can be considered a working state. At this time, there is a certain probability that a photon incident on the single-photon avalanche diode will trigger an avalanche effect. Each time an avalanche effect occurs, the single-photon avalanche diode enters the quenched state and can no longer sense photons to output light sensing signals. The quenched state can be considered a non-working state. A single-photon avalanche diode in the quenched state needs to be reset before it can return to the Geiger state to continue sensing photons. The duration of the quenched state is the dead time of the photon avalanche diode. When a sensing period begins, the single-photon avalanche diodes used by the transmitting module 110 to send out detection light signals and the receiving module 120 to receive light signals are usually turned on synchronously. When the relative intensity of the ambient light is too high, a large number of single-photon avalanche diodes will be triggered to avalanche together in a short period of time at the beginning of the sensing period and enter the dead time. The generated light sensing signal counts are accumulated in several time bins at the beginning of the sensing period, forming a pile-up effect. Since the number of single-photon avalanche diodes in the receiving module 120 is limited, there will not be enough single-photon avalanche diodes left to continue sensing the returned light signal. If there is a detection light signal reflected by the target object in the returned light signal at this time, it will be missed, thereby forming a blind spot for ranging. Specifically, for example, assuming that a photosensitive pixel of the receiving module 120 includes 4 independent single-photon avalanche diodes, when only the receiving module 120 is turned on, the 4 independent single-photon avalanche diodes start working at the same time. The statistical histogram of the photon count of only ambient light can be obtained through Monte Carlo method simulation, such as Figure 3As shown. It can be seen that when the ambient light is strong, in the time bin with the initial timestamp of 1 (X=1) when the receiving module 120 is turned on, there will be an obvious very high count of 767 (Y=767), and the ambient light light sensing signal count fluctuates greatly, and even if there is a returned detection light signal, it will be submerged. If the transmitting module and the receiving module are turned on at the same time under the condition of the same ambient light intensity, the following can be obtained: Figure 4 The photon counting statistical histogram shown in the figure shows that for the detection light signal reflected back by a close object, for example, the timestamp of the time bin in which the returned detection light signal is sensed is 9. Due to the pile-up effect caused by the ambient light at the initial moment, the count is high and the fluctuation is large. It is difficult to determine the position of the corresponding signal peak formed by the detection light signal superimposed on the ambient light background, that is, there is a corresponding ranging blind area, especially in the close-range range corresponding to the time bin close to the initial moment of the sensing period. When the opening time of the receiving module 120 exceeds a certain threshold, that is, after the single-photon avalanche diode has been working for a period of time, for example, the corresponding Figure 3 In the time bin with timestamp 28, the light sensing signal count caused by ambient light tends to be stable, which means that after multiple quenching and resetting, the different single-photon avalanche diodes in the pixel resume working at randomly distributed times and are no longer synchronized like when the receiving module 120 is just turned on. At this time, the influence of ambient light is significantly reduced.

[0066] Therefore, in order to solve the problem of the distance measurement blind area caused by the pile-up effect of the time-of-flight ranging sensor 100 in a high ambient light scenario. Figure 2 As shown, the time-of-flight ranging sensor further includes a control module 150. The control module 150 is configured to control the relative start-up time of the transmitting module 110 and the receiving module 120 within a specified sensing period to reduce the pile-up effect caused by ambient light, which can improve the ranging accuracy to a certain extent.

[0067] In some embodiments, for at least one sensing period in a partition detection period, the control module 150 controls the receiving module 120 to be turned on at a first time, and controls the transmitting module 110 to be turned on at a second time, and the second time is later than the first time.

[0068] The control module 150 can be independent of the processing module 130 and the driving circuit 111. The control module 150 can send a control signal to the driving circuit 111 to control the light source 112 to emit light or turn off through the driving circuit 111. Specifically, for example, the control module 150 sends a light source turn-on signal to the driving circuit 111. After the driving circuit 111 receives the light source turn-on signal, it drives the light source 112 to emit light, thereby controlling the light-emitting module 110 to turn on. The control module 150 can control the photoelectric sensor 122 to turn on the power supply, or disconnect the power supply, to control the receiving module 120 to start working or reset. Of course, the control module 150 can also control the receiving module 120 to turn on or reset by sending a control signal to the photoelectric sensor 122.

[0069] In some embodiments, the control module 150 may be integrated into the processing module 130, so that the processing module 130 may be used as the control module 150 and realize the functions of the control module 150. Of course, in other embodiments, the control module 150 may also be integrated into the driving circuit 111, so that the driving circuit 111 may be used as the control module 150 and realize the functions of the control module 150.

[0070] In order to reduce the interference of ambient light on the detection light signal, the receiving module 120 is exposed to the ambient light in advance before the transmitting module 110 sends the detection light signal. In the case of only ambient light, there is a certain randomness in the probability that different single-photon avalanche diodes are triggered to avalanche by photons of ambient light. These random differences will be amplified after the accumulation of multiple quenching and resetting. In this way, after the receiving module 120 is turned on for a period of time, multiple single-photon avalanche diodes will be in a state of randomly staggered avalanche effects instead of being avalanched together as when the receiving module 120 is just turned on. At this time, when the transmitting module 110 is turned on at the second time, when the detection light signal emitted by the transmitting module 110 is reflected by an external object and returned to the receiving module 120, the probability that there are still single-photon avalanche diodes available to sense the returned detection light signal will be significantly increased.

[0071] A partition detection period may include a plurality of sensing periods corresponding to the emission of the detection light signal, and the transmitting module 110 may be turned on later than the receiving module 120 in at least one sensing period. For example, the transmitting module 110 may be controlled to be turned on later than the receiving module 120 in the first sensing period of the partition detection period. That is, in the first sensing period of the partition detection period, the control module 150 controls the receiving module 120 to be turned on at a first time, and controls the transmitting module 110 to be turned on at a second time later than the first time. At this time, the multiple single-photon avalanche diodes of the receiving module 120 have been randomly avalanched and requenched and reset multiple times under the action of ambient light, and their respective working states are no longer synchronized, which can significantly reduce the pile-up effect caused by the simultaneous avalanche of a large number of single-photon avalanche diodes.

[0072] It should be understood that the delay time of the second time compared to the first time can be positively correlated with the ambient light intensity. Specifically, the stronger the ambient light, the longer the delay time of the second time compared to the first time. In the case of stronger ambient light, the multiple single-photon avalanche diodes of the receiving module 120 need more time to increase the number of quenching resets, thereby increasing the randomness of the working states of different single-photon avalanche diodes to weaken the pile-up effect. In this way, when the ambient light intensity is strong, the delay time of the second time compared to the first time can be increased. In the case of weak ambient light intensity, the transmitting module 110 can be turned on earlier, that is, the delay time of the second time compared to the first time is shortened. In some embodiments, the delay time of the second time compared to the first time can be a specified multiple of the dead time of the single-photon avalanche diode, and the value range of the specified multiple is, for example, 2-15, 5-20, 10-30, etc. For example, the dead time of a single photon avalanche diode is usually 5-30ns, and the delay time of the second time compared to the first time can be 10ns-300ns. Specifically, the control module 150 controls the counting unit 131 to delay 30 time bins after the receiving module 120 starts working before starting to count the output light sensing signal to obtain the following information: Figure 5 The photon counting statistics histogram shown is from Figure 5 It can be seen that the photon count fluctuations caused by ambient light have generally stabilized at this time.

[0073] Optionally, in some embodiments, the receiving module 120 remains turned on after the first sensing period of a partition detection period is turned on until the end of the partition detection period, that is, the receiving module 120 will not stop turning on again at the connection moment between multiple sensing periods after the first sensing period, but will remain turned on until the end of the entire partition detection period. In this case, the longer the receiving module 120 is turned on, the higher the randomness of the quenching and resetting of different single-photon avalanche diodes, and the stronger the inhibitory effect on the influence of ambient light. On this basis, within a partition detection period, for multiple sensing periods after the first sensing period, since the receiving module 120 remains turned on, there is no need to turn it on again. Correspondingly, there is no need for the transmitting module 110 to be turned on later relative to the receiving module 120, but it can be turned on at any time in the corresponding sensing period according to other design requirements.

[0074] Optionally, in some other embodiments, the sensing period in which the receiving module 120 is turned on first and then the transmitting module 110 is turned on is not limited to the first sensing period of the partition detection period, but can also be the second sensing period, or the third sensing period, or any number of sensing periods. Inspired by the technical essence of this application, technicians in the relevant field can make settings according to actual needs. In some embodiments, after each sensing period ends, the transmitting module 110 and the receiving module 120 can be reset, and after each sensing period starts, the transmitting module 110 is controlled to start working later than the receiving module 120.

[0075] In some embodiments, Figure 2 As shown, the control module 150 may include a light intensity acquisition unit 151 , a delay duration determination unit 153 , an emission control unit 154 and a sensing control unit 155 .

[0076] The light intensity acquisition unit 151 can be used to acquire the intensity of ambient light. For example, in some embodiments, the time-of-flight ranging sensor 100 may further include a light intensity sensor 160, and the light intensity acquisition unit 151 is configured to control the light intensity sensor 160 to acquire the ambient light intensity of the measurement scene, and the delay duration determination unit 113 is configured to determine the delay duration of the second time compared to the first time according to the acquired ambient light intensity. The delay duration determination unit 113 can determine the delay duration according to a preset relationship between the ambient light intensity and the delay duration. Optionally, the relationship can be a calculation formula between the ambient light intensity and the delay duration, or can be a corresponding relationship between the ambient light intensity and the delay duration determined by testing and calibration.

[0077] For example, in some other embodiments, the light intensity acquisition unit 151 can also determine the intensity of the ambient light through the photon count value caused by the ambient light. Specifically, the sensing control unit 155 can control the receiving module 120 to be turned on separately for a preset period of time before starting a partition detection period. The photon count value accumulated by the receiving module 120 during this period is positively correlated with the intensity of the ambient light, so that the light intensity acquisition unit 151 can determine the intensity of the ambient light accordingly.

[0078] The sensing control unit 155 is used to control the receiving module 120 to start working at the first time corresponding to the partition detection period, and the transmitting control unit 154 is used to control the transmitting module 110 to start working at the second time corresponding to the partition detection period according to the determined delay duration. The sensing control unit 155 is also used to control the processing module 130 to obtain the distance information of the internal and external objects of the measurement scene based on the processing and analysis of the corresponding light sensing signal generated after the transmitting module 110 starts to emit the detection light signal during the sensing period. According to the above operation, the detection light signal echo superimposed on the ambient light noise background with relatively uniform and stable fluctuations can be clearly distinguished. Specifically, Figure 6 As shown, even if the object is at a close distance (time bin with timestamp X=9), a clear signal peak (peak photon count Y=1023) can be formed without being drowned by the photon count caused by ambient light, thereby avoiding the existence of a ranging blind spot in the time-of-flight ranging sensor 100 at a close distance due to the pile-up effect.

[0079] In some embodiments, all or part of the functional units in the control module 150 and / or the processing module 130 may include firmware solidified in the memory 220 or computer software code stored in the memory 220, and executed by the corresponding one or more processors 210 to control the relevant components to implement corresponding functions.

[0080] In some embodiments, some or all of the functional units in the control module 150 and / or the processing module 130 may also be implemented by hardware, for example, by any one of the following technologies or a combination thereof: a discrete logic circuit having a logic gate circuit for implementing logical functions on a data signal, a dedicated integrated circuit having a suitable combinational logic gate circuit, a programmable gate array (PGA), a field programmable gate array (FPGA), a driving circuit for a specific object, etc.

[0081] It can be understood that all or part of the functional units in the control module 150 and / or the processing module 130 can be set in the time-of-flight ranging sensor 100, for example: set on the light source 112 of the transmitting module 110, the driving circuit 111 and / or the photoelectric sensor 122 of the receiving module 120; all or part of the functional units in the control module 150 and / or the processing module 130 can also be set at other locations on the electronic device 200 except the photoelectric sensor 122, for example: set on the main circuit board of the electronic device 200.

[0082] Please refer to Figure 7 . The present application also provides a control method corresponding to the time-of-flight ranging sensor 100 of the aforementioned embodiment. The time-of-flight ranging sensor 100 includes a transmitting module 110 and a receiving module 120, the transmitting module 110 transmits a plurality of detection light signals in a preset time sequence within a partition detection period, the partition detection period is divided into a plurality of sensing periods corresponding to the detection light signals, the receiving module 120 cooperates according to the sensing period to sense the light signal from the measurement scene and outputs a corresponding light sensing signal; for at least one sensing period in a partition detection period, the control method may include the following steps.

[0083] Step S110: Start the receiving module at the first time.

[0084] Step S120: Turn on the transmitting module at a second time; wherein the second time is later than the first time.

[0085] By turning on the receiving module before turning on the transmitting module, the working states of different single-photon avalanche diodes on the receiving module have lost consistency with each other before turning on the transmitting module, thereby reducing the impact of the pile-up effect caused by the synchronous operation of the single-photon avalanche diodes on ranging.

[0086] In some embodiments, the receiving module 120 remains turned on after the first sensing period of a partition detection period is turned on until the end of the partition detection period. For multiple sensing periods after the first sensing period of a partition detection period, the transmitting module 110 no longer needs to be delayed to turn on, but can be turned on at the beginning of the corresponding sensing period.

[0087] It should be understood that the specific examples in this article are only intended to help those skilled in the art to better understand the embodiments of the present application, rather than to limit the scope of the present invention.

[0088] It can be understood that in the various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0089] It can be understood that the various embodiments described in this application can be implemented individually or in combination, and the embodiments of this application are not limited to this.

[0090] Unless otherwise stated, all technical and scientific terms used in the embodiments of the present application are the same as the meanings generally understood by those skilled in the art of the technical field of the present application. The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the scope of the present application. The term "and / or" used in the present application includes any and all combinations of one or more related listed items. The singular forms "a kind of", "above" and "the" used in the embodiments of the present application and the appended claims are also intended to include majority forms, unless the context clearly indicates other meanings.

[0091] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0092] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0093] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0094] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0095] The above is only a specific embodiment of the present application, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A control module for a time-of-flight ranging sensor, characterized in that: The time-of-flight ranging sensor includes a transmitting module, a receiving module and a processing module. The time-of-flight ranging sensor performs distance detection on partitions of different orientations in a measurement scene in a time-sharing manner according to a preset scanning mode. The detection process of one partition is regarded as a partition detection period. The transmitting module transmits a plurality of detection light signals to the corresponding partition in the measurement scene according to a preset time sequence in a partition detection period. The partition detection period is divided into a plurality of sensing periods corresponding to the detection light signals. The receiving module includes a single-photon avalanche diode for sensing light signals. The single-photon avalanche diode works in coordination according to the sensing period to sense the light signal from the corresponding partition in the measurement scene. The processing module is used to process and analyze the light sensing signal generated by the receiving module corresponding to the light signal received by the receiving module to obtain the time when the detection light signal echo is sensed by the receiving module, and obtain the distance information of the external objects in the corresponding partition according to the time difference between the emission time of the detection light signal and the time when the reflection is sensed. Among them, for at least one sensing period in the partition detection period, the control module controls to turn on the receiving module at a first time, and controls to turn on the transmitting module at a second time, and the second time is later than the first time.

2. The control module according to claim 1, characterized in that: The control circuit determines the delay duration of the second time compared to the first time according to the ambient light intensity of the measurement scene; wherein the delay duration of the second time compared to the first time is positively correlated with the ambient light intensity.

3. The control module according to claim 2, characterized in that: The time-of-flight ranging sensor further includes a light intensity sensor, and the control module acquires the ambient light intensity of the measurement scene through the light intensity sensor.

4. The control module according to claim 2, characterized in that: The control module is configured to control the receiving module to be turned on separately for a preset period of time before starting a partition detection period, and determine the ambient light intensity of the measurement scene according to the count value of the light sensing signal accumulated by the receiving module during this period.

5. The control module according to claim 2, characterized in that: The delay time is a specified multiple of the dead time of the single photon avalanche diode.

6. The control module according to claim 1, characterized in that: The control module is configured to control the receiving module to remain turned on after being turned on at the first time in the first sensing period of the partition detection period until the partition detection period ends.

7. The control module according to claim 1, characterized in that: The control module is configured to control the processing module to obtain the distance information based on processing and analysis of the light sensing signal generated after the emission module starts to emit the detection light signal within the sensing period.

8. A time-of-flight ranging sensor, characterized in that: The time-of-flight ranging sensor is configured to sense an external object in a measurement scene based on the time-of-flight principle to obtain distance information of the external object, and the time-of-flight ranging sensor includes: The transmitting module is configured to transmit a plurality of detection light signals to the measurement scene according to a preset time sequence within a partition detection period, wherein the partition detection period is divided into a plurality of sensing periods corresponding to the detection light signals; A receiving module is configured to work together according to the sensing period to sense the optical signal from the measurement scene a processing module configured to process and analyze the light sensing signal generated by the receiving module in response to the light signal received by the receiving module to obtain the time when the detection light signal echo is sensed by the receiving module, and obtain the distance information of the external object according to the time difference between the emission time of the detection light signal and the time when the reflection is sensed; and A control module as claimed in any one of claims 1 to 7.

9. An electronic device, characterized in that: include: A processor, a memory, and the time-of-flight ranging sensor as claimed in claim 8, wherein the time-of-flight ranging sensor and the memory are respectively connected to the processor, and the processor is configured to control the electronic device according to the distance information obtained by the time-of-flight ranging sensor.

10. A control method for a time-of-flight ranging sensor, characterized in that: The time-of-flight ranging sensor includes a transmitting module and a receiving module. The time-of-flight ranging sensor performs distance detection on partitions in different directions in a measurement scene in a time-sharing manner according to a preset scanning mode. The detection process of one partition is regarded as a partition detection period. The transmitting module transmits a plurality of detection light signals to a corresponding partition in the measurement scene according to a preset time sequence in a partition detection period. The partition detection period is divided into a plurality of sensing periods corresponding to the detection light signals. The receiving module includes a single-photon avalanche diode for sensing light signals. The single-photon avalanche diode works in coordination according to the sensing period to sense light signals from corresponding partitions in the measurement scene and output corresponding light sensing signals. For at least one sensing period in a partition detection period, the control method includes: At the first opportunity, start the receiving module; At a second time, the transmitting module is turned on; wherein the second time is later than the first time.

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