Photoelectric detection device, multi-channel photoelectric detection system and lidar including the thereof

Abstract

This application discloses a photoelectric detection device, a multi-channel photoelectric detection system, and a lidar including the same. The photoelectric detection device includes: a photodetector; a first port configured as the cathode of the photodetector; a second port configured as the anode of the photodetector; a third port configured as a reference voltage port, wherein a gating circuit is provided between the first port and the third port and connected in parallel with the photodetector, and the photodetector is connected to the gating circuit through a signal coupling capacitor; and a fourth port configured as an output port, wherein the fourth port is connected to the gating circuit.

Description

Technical Field

[0001] This invention relates to the field of photoelectric detection technology, and in particular to a photoelectric detection device with a multi-channel photoelectric detection system. Background Technology

[0002] Single-photon detectors, as highly sensitive photoelectric detection devices at the photon counting level, have wide applications in quantum communication, LiDAR, fluorescence spectroscopy analysis, medical imaging, and high-energy physics experiments. With the development of these technologies, the performance requirements for single-photon detectors are constantly increasing, particularly in areas such as multi-channel parallel detection, time resolution, signal readout efficiency, and system integration, where they face significant challenges.

[0003] Currently, single-photon avalanche diode (SPAD) arrays are one of the main technological approaches for realizing single-photon detection. Among them, silicon photomultiplier tubes (SiPMs) are widely used due to their advantages such as high gain, low operating voltage, and insensitivity to magnetic fields. Existing SiPM devices are mainly divided into two types: traditional two-port devices and improved three-port devices. Two-port devices have a simple structure, but their signal readout methods are limited; three-port devices add a fast output port, improving the signal readout speed, but still cannot directly solve the channel isolation problem in multi-channel parallel readout.

[0004] When constructing a single-photon detector array, it is often necessary to address the signal readout problem of parallel channels. Existing technologies mostly employ external analog switching circuits to achieve time-division multiplexing of multi-channel signals. For example, common lidar systems use external multiplexers to sequentially select different detector channels. While this approach is feasible, it increases system complexity, signal delay, and noise introduction, while also reducing time resolution.

[0005] Furthermore, existing single-photon detectors face challenges in multi-channel applications, including signal crosstalk, increased timing jitter, and limited readout speed. Particularly in high-density integrated detector arrays, insufficient isolation between channels leads to signal interference, reducing detection accuracy; while complex selection switch networks introduce additional parasitic capacitance, prolonging signal rise time and impacting the overall system response speed and time resolution.

[0006] Therefore, there is an urgent need for a novel single-photon detector structure design that can achieve a simplified multi-channel signal readout architecture while maintaining high sensitivity and fast response characteristics, reducing dependence on external control circuits, improving system integration, and ensuring good isolation performance between multiple channels. Summary of the Invention

[0007] This application provides a photoelectric detection device and a multi-channel photoelectric detection system. Utilizing a four-port design, the conduction or cutoff of the gating circuit can be controlled by the bias voltage between the cathode and the reference voltage port. This achieves a simplified multi-channel signal readout architecture while maintaining high sensitivity and fast response characteristics, reducing dependence on external control circuits, improving system integration, and ensuring good isolation performance between multiple channels.

[0008] The first aspect of this application discloses a photoelectric detection device, comprising: a photodetector; a first port configured as the cathode of the photodetector; a second port configured as the anode of the photodetector; a third port configured as a reference voltage port, wherein a gating circuit is provided between the first port and the third port and connected in parallel with the photodetector, and the photodetector is connected to the gating circuit through a signal coupling capacitor; and a fourth port configured as an output port, wherein the fourth port is connected to the gating circuit.

[0009] According to the photoelectric detection device of this application, by embedding the gating circuit between the cathode of the photodetector and the reference voltage port, and using a signal coupling capacitor to couple the detection signal, a high degree of integration of photoelectric detection and channel gating functions is achieved. This structure fundamentally simplifies the design of multi-channel systems, avoids the complex wiring, signal integrity degradation, and additional power consumption problems caused by traditional external switch matrices, and lays the foundation for building compact and efficient multi-channel detection arrays.

[0010] In the photoelectric detection device disclosed in this application, the gating circuit is configured such that when the first port has a positive bias voltage relative to the third port, the gating circuit is turned on, and the pulse signal output by the photodetector can be output to the fourth port through the signal coupling capacitor; when the first port has a reverse bias voltage relative to the third port, the gating circuit is turned off, and the pulse signal output by the photodetector cannot be output to the fourth port through the signal coupling capacitor.

[0011] According to the photoelectric detection device of this application, the core control logic of the gating circuit is defined: the polarity of the relative bias voltage between the first port (cathode) and the third port (reference voltage port) is used to control the on / off state of the signal path. This voltage control method is direct and efficient, requiring no complex logic control unit. The channel can be quickly turned on and off simply by adjusting the cathode bias voltage, resulting in a fast response speed and a simple and reliable control circuit.

[0012] In the photoelectric detection device disclosed in this application, the gating circuit includes a gating switch and a voltage divider resistor. When the gating switch is turned on, the internal resistance value is less than the resistance value of the voltage divider resistor. When the gating switch is turned off, the isolation capacitance value is less than the junction capacitance value of the photodetector.

[0013] The photoelectric detection device according to this application provides a specific and easily implementable circuit architecture by defining the gating circuit as including a gating switch and a voltage divider resistor. It also reduces the loss of the photodetector's output signal and does not affect the output of other channels connected in parallel when the gating circuit is turned off. The voltage divider resistor can be used to precisely set and adjust the driving conditions of the gating switch, ensuring its reliable operation under a specified voltage.

[0014] In the photoelectric detection device disclosed in this application, the selection switch is a diode, the voltage divider resistor includes a first resistor and a second resistor, the positive terminal of the diode is connected to the first port through the first resistor, and the negative terminal of the diode is connected to the third port through the second resistor.

[0015] The photoelectric detection device according to this application uses a diode as a selection switch in combination with a specific voltage divider resistor configuration, which is a preferred and low-cost specific circuit scheme for the selection circuit control logic. This structure utilizes the unidirectional conductivity of the diode to realize the on / off function under the polarity control of the bias voltage, and the circuit is simple and has stable performance.

[0016] In the photoelectric detection device disclosed in this application, the signal coupling capacitor and the fourth port are respectively connected to the two ends of the selection switch.

[0017] According to the photoelectric detection device of this application, the signal coupling capacitor and the signal output port are respectively connected to the two ends of the gating switch, which ensures that the pulse signal generated by the photoelectric detector can be coupled to the output port through the signal coupling capacitor only when the gating switch is turned on. This achieves precise synchronization between signal transmission and gating control, and effectively isolates the influence of DC bias on the output signal.

[0018] In the photoelectric detection device disclosed in this application, the photoelectric detector is a single-photon avalanche diode or a silicon photomultiplier tube.

[0019] According to the photoelectric detection device of this application, the photoelectric detector is specifically defined as a single-photon avalanche diode (SPAD) or a silicon photomultiplier tube (SiPM), which clarifies the direct application value of this solution in the field of high sensitivity and weak light detection.

[0020] The photoelectric detection device disclosed in this application further includes a signal processing circuit. The input terminal of the signal processing circuit is connected to the fourth port and is used to amplify and / or shape the pulse signal output by the photoelectric detector.

[0021] According to the photoelectric detection device of this application, by adding subsequent signal processing circuitry, the weak pulse signal output by the photodetector can be amplified and shaped, thereby improving the signal-to-noise ratio and edge quality, making it more suitable for subsequent digital processing, long-distance transmission, or precise time measurement.

[0022] In the photoelectric detection device disclosed in this application, the signal processing circuit includes: an amplifier, the input of which is connected to the fourth port; a signal comparator or LVDS interface driver, the input of which is connected in parallel to the output of the amplifier; wherein the signal comparator or LVDS interface driver is configured to have different DC threshold levels for extracting over-threshold time information at different time points from the amplified pulse signal.

[0023] According to the photoelectric detection device of this application, by configuring a comparator or LVDS interface driver, the threshold time information can be extracted from the amplified pulse output signal to achieve fine calibration with sub-nanosecond time resolution; without adding delay line hardware, the sampling time point can be flexibly set by simply adjusting the DC threshold (-Vth) of each channel, effectively suppressing the timing deviation between channels, and significantly improving the timing accuracy and system adaptability in applications such as time-correlated single-photon counting (TCSPC).

[0024] The second aspect of this application discloses a multi-channel photoelectric detection system, comprising M groups, each group having N of the aforementioned photoelectric detection devices. All photoelectric detection devices share a second port and a third port. The N photoelectric detection devices in each group are connected in parallel and share a first port. The Nth photoelectric detection device in each group shares a fourth port. M is an integer greater than or equal to 2, and N is an integer greater than or equal to 1.

[0025] According to the multi-channel photoelectric detection system of this application, the multi-channel system adopts the architecture of "common anode-common reference voltage (common ground)-grouped cathode / output". The independent and controllable gating mechanism of each group of channels supports a flexible time-division multiplexing readout strategy, which maintains excellent signal isolation while ensuring high channel density, and provides a highly integrated, low-cost and easily expandable hardware implementation solution for the detection array.

[0026] A third aspect of this application discloses a lidar, including the aforementioned multi-channel photoelectric detection system.

[0027] The lidar according to this application provides a detection solution with high integration, high channel density, rapid gating, and high-precision time measurement potential, which helps to achieve overall optimization of lidar system performance, size, cost, and reliability. Attached Figure Description

[0028] Figure 1This is a circuit diagram of one embodiment of the photoelectric detection device involved in this application;

[0029] Figure 2 This is a circuit diagram of another embodiment of the photoelectric detection device involved in this application;

[0030] Figure 3 This is a schematic diagram of the signal processing circuit involved in this application;

[0031] Figure 4 This is a circuit diagram of one embodiment of the multi-channel photoelectric detection system involved in this application;

[0032] Figure 5 This is a circuit diagram of another embodiment of the multi-channel photoelectric detection system involved in this application. Detailed Implementation

[0033] The present application will be further described below with reference to specific embodiments and accompanying drawings. It is to be understood that the illustrative embodiments of this disclosure are merely for explaining the present application and not for limiting it. Furthermore, for ease of description, the accompanying drawings show only the parts relevant to the present application, and not all of the structures or processes.

[0034] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with preferred embodiments, this does not mean that the features of this invention are limited to this embodiment. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of this application. To provide a thorough understanding of this application, many specific details will be included in the following description. This application may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0035] Unless the context otherwise specifies, the terms “contains,” “has,” and “includes” are synonyms. The phrase “A / B” means “A or B.” The phrase “A and / or B” means “(A and B) or (A or B).”

[0036] It should be understood that although terms such as "first," "second," etc., may be used herein to describe various components, units, or data, these components, units, or data should not be limited by these terms. These terms are used merely to distinguish one feature from another. For example, without departing from the scope of the exemplary embodiments, a first feature may be referred to as a second feature, and similarly, a second feature may be referred to as a first feature.

[0037] It should be understood that although directional terms such as "up," "down," "left," and "right" may be used here to describe the positional relationship between the various components, these directional terms are only for the convenience of understanding and are not intended to limit the scope of protection of this application.

[0038] It should be noted that in this specification, similar reference numerals and letters in the accompanying drawings indicate similar items. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0040] Figure 1 This is a circuit diagram of one embodiment of the photoelectric detection device involved in this application. Figure 1 In the illustrated embodiment, the photodetector includes a photodetector 1, a first port 2 configured as the cathode of the photodetector 1, a second port 3 configured as the anode of the photodetector 1, and a third port 4 configured as a reference voltage port (G). It should be noted that the reference voltage port can be a ground port, i.e., the reference voltage is 0, or it can be a port providing any reference voltage from 0 to Vov, where Vov is the overvoltage of the photodetector, i.e., the difference between the operating bias voltage and its own breakdown voltage. A gating circuit is configured between the first port 2 and the third port 4, connected in parallel with the photodetector 1. The photodetector 1 is connected to the gating circuit through a signal coupling capacitor 6. The fourth port 5 is configured as an output port (OUT) and connected to the gating circuit.

[0041] A gating circuit is located between the first port 3 and the third port 4, connected in parallel with the photodetector 1. This gating circuit includes a gating switch and voltage divider resistors. Specifically, as shown... Figure 1 In the illustrated embodiment, the selection switch is a diode 8, and the voltage divider resistors include a first resistor 7 and a second resistor 8. The anode of diode 8 is connected to the first port 2 through the first resistor, and the cathode of diode 8 is connected to the third port 4 through the second resistor. The signal coupling capacitor 6 connects the photodetector 1 to the cathode terminal of diode 8. When photodetector 1 receives light / photon irradiation under reverse bias voltage, it generates a pulse signal. This pulse signal is coupled and transmitted to the selection circuit through the signal coupling capacitor 6, and then output through the fourth port 5 of the diode 8 connected to the anode in the selection circuit.

[0042] When a bias voltage that is positive relative to the third port 4 is applied to the first port 2 (i.e., the voltage at the first port 2 is higher than the voltage at the third port 4), and the bias voltage exceeds the forward conduction voltage of diode 8, diode 8 conducts forward. At this time, the pulse signal generated by photodetector 1 is coupled through signal coupling capacitor 6 and passes through the conducting diode 8, outputting a voltage pulse signal from the fourth port 5. The internal resistance of diode 8 when it is conducting is less than the resistance values ​​of the first resistor 7 and the second resistor 9. The resistance values ​​of the first resistor 7 and the second resistor 9 can be selected as 1 kiloohm, or adjusted according to the magnitude of the bias voltage, to ensure the operating performance of diode 8 and reduce the loss of the pulse signal generated by photodetector 1.

[0043] When a bias voltage that is negative or zero relative to the third port 4 is applied to the first port 2 (i.e., the voltage at the first port 2 is lower than or equal to the voltage at the third port 4), the bias voltage of the photodetector 1 decreases, its detection capability weakens, and the diode 8 is in a cutoff state due to zero or reverse bias, exhibiting extremely high impedance. At this time, even if the photodetector 1 can generate a weak pulse signal, it will be blocked by the high-impedance diode 8 and cannot be transmitted to the fourth port 5. Furthermore, the capacitance of the isolation capacitor when the diode 8 is in the cutoff state is less than the junction capacitance of the photodetector 1, therefore it will not affect the output signals of other channels.

[0044] In this application, it is preferred that the internal resistance of the diode when it is in the conducting state is much smaller than the resistance of the first resistor and the second resistor, and the capacitance of the isolation capacitor when the diode is in the cut-off state is much smaller than the capacitance of the junction capacitance of the photodetector. Here, "much smaller" means that the two values ​​differ by at least one order of magnitude, that is, by 10 times or more. Preferably, they can differ by two orders of magnitude, that is, by 100 times or more.

[0045] In a preferred embodiment of this application, photodetector 1 can be a SPAD, which is a photodiode operating in Geiger mode at a voltage much higher than its breakdown voltage. A single photon can trigger an avalanche current pulse, achieving single-photon detection. Photodetector 1 can also be a SiPM, which is an integrated circuit of multiple SPAD units connected in parallel. Its total output current is proportional to the number of triggering units (i.e., the number of photons), thus possessing both single-photon sensitivity and photon number resolution. However, the photodetector of this application is not limited to the above two cases; other devices operating under reverse bias voltage conditions can also be selected, such as ordinary avalanche photodiodes (APDs) or photomultiplier tubes (PMs).

[0046] It should be further noted that the switching device in this application is not limited to a diode. Other semiconductor devices that can replace a diode to achieve forward conduction and reverse cutoff, which can be easily conceived by those skilled in the art, are also within the scope of protection of this application, such as metal-oxide-semiconductor field-effect transistors (MOSFETs), junction field-effect transistors (JFETs), or bipolar junction transistors (BJTs).

[0047] Figure 2 This is a circuit diagram of another embodiment of the photoelectric detection device involved in this application. Figure 2 The illustrated embodiments and Figure 1 The difference lies in that photodetector 1 is connected to the positive terminal of diode 8 in the gating circuit via signal coupling capacitor 6, and the fourth port 5 is connected to the negative terminal of diode 8. In other words, the signal coupling capacitor 6 and the fourth port 5, used for pulse signal coupling of photodetector 1, are respectively connected to the two ends of a switching switch, and signal output is achieved by switching the switch on or off.

[0048] Figure 3 This is a schematic diagram of the signal processing circuit involved in this application. Figure 3 As shown, the signal processing circuit includes an amplifier 10 and a signal comparator 12. The input terminal of the amplifier 10 is connected to the fourth port of the photodetector, and the input terminal of the signal comparator 12 is connected in parallel to the output terminal of the amplifier 10 through a voltage divider resistor. The amplifier 10 linearly amplifies the small-amplitude pulse signal V_in output by the photodetector, outputting a higher signal-to-noise ratio amplified pulse signal V_amp. By adjusting the resistance value of the voltage divider resistor, the DC level of the signal comparator 12 can be adjusted to -Vth, thereby recording the moment when the amplified pulse signal V_amp crosses the threshold Vth, which is used as the reception time of the echo optical signal.

[0049] It should be noted that an LVDS interface driver can also be used to replace the signal comparator to achieve the same function.

[0050] This application also provides a multi-channel photoelectric detection system. Figure 4 This is a circuit diagram of one embodiment of the multi-channel photoelectric detection system involved in this application. Figure 4As shown, the multi-channel photodetector system includes four or more groups of photodetectors 21-24, each group comprising two photodetectors connected in parallel, forming an eight-channel photodetector system. The eight photodetectors share the same second port and the same third port, meaning all photodetectors share the cathode and reference voltage port. The two parallel photodetectors in each group share a first port, i.e., they share the anode. The first photodetector in each group shares a fourth port, and the second photodetector in each group shares another fourth port; that is, the first, third, fifth, and seventh photodetectors share the first output port (OUT1), and the second, fourth, sixth, and eighth photodetectors share the second output port (OUT2). By sequentially applying a positive bias voltage to the cathodes of each group of photodetectors, the two photodetectors in each group can be sequentially selected, thereby simultaneously outputting two pulse signals. Figure 4 The embodiment shows a 4×2 eight-channel photoelectric detection system that outputs two pulse signals each time. However, this application is not limited to this. The multi-channel photoelectric detection system provided in this application can also be an M×N multi-channel photoelectric detection system, including N output ports, and outputs N pulse signals each time.

[0051] Figure 5 This is a circuit diagram of another embodiment of the multi-channel photoelectric detection system involved in this application. Figure 5 The illustrated embodiments and Figure 4 The difference is that the photodetector is connected to the positive terminal of the diode in the gating circuit through a signal coupling capacitor, and the fourth port is connected to the negative terminal of the diode.

[0052] This application also provides a lidar comprising the multi-channel photoelectric detection system described above. In this lidar, each photoelectric detection device in the multi-channel photoelectric detection system corresponds to one or a column of lidar receiving pixels. The lidar control system, according to a preset scanning sequence, dynamically adjusts the bias voltage applied to the first port 4 of each group of photoelectric detection devices to time-division select different groups of photoelectric detection devices, thereby achieving orderly reception of echo light signals from different field-of-view areas. The selected photoelectric detection device receives the echo light signal, generates a pulse output signal, amplifies and performs multi-threshold discrimination processing to obtain the arrival time data of the echo light signal, and sends it to the lidar's signal processor for calculating the target distance and further constructing a point cloud image.

[0053] This application proposes a four-port photodetector device and system, which integrates a voltage-controlled gating switch (such as a diode) with the photodetector body (e.g., SPAD / SiPM) in the cathode circuit, achieving a high degree of integration between the photodetector unit and the channel gating function. According to the technical solution of this application, the external analog switch matrix and independent control logic required in traditional multi-channel detection systems are eliminated. The signal path can be directly controlled by adjusting the bias voltage of the photodetector cathode. This structure allows a single photodetector unit to output a high-impedance state when not selected, thus allowing the outputs of multiple detectors to be directly connected in parallel without isolation devices. This significantly reduces the number of physical signal traces and back-end processing channels in array applications, significantly reducing system complexity, power consumption, and cost. This technology provides a compact, efficient, and reliable receiver hardware solution for applications such as lidar that require high-density, multi-channel, fast gating, and accurate ranging.

[0054] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Where there is no conflict, the embodiments and features described in the embodiments of this application can be combined with each other. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A photoelectric detection device, characterized in that, include: Photodetector; The first port is configured as the cathode of the photodetector; The second port is configured as the anode of the photodetector; The third port is configured as a reference voltage port. A gating circuit is provided between the first port and the third port and connected in parallel with the photodetector. The photodetector is connected to the gating circuit through a signal coupling capacitor. The fourth port is configured as an output port and is connected to the gating circuit.

2. The photoelectric detection device according to claim 1, characterized in that, The gating circuit is configured such that when the first port has a positive bias voltage relative to the third port, the gating circuit is turned on, and the pulse signal output by the photodetector can be output to the fourth port through the signal coupling capacitor; when the first port has a reverse bias voltage relative to the third port, the gating circuit is turned off, and the pulse signal output by the photodetector cannot be output to the fourth port through the signal coupling capacitor.

3. The photoelectric detection device according to claim 2, characterized in that, The selection circuit includes a selection switch and a voltage divider resistor. When the selection switch is turned on, its internal resistance is less than that of the voltage divider resistor. When the selection switch is turned off, its isolation capacitance is less than that of the junction capacitance of the photodetector.

4. The photoelectric detection device according to claim 3, characterized in that, The selector switch is a diode, and the voltage divider resistor includes a first resistor and a second resistor. The positive terminal of the diode is connected to the first port through the first resistor, and the negative terminal of the diode is connected to the third port through the second resistor.

5. The photoelectric detection device according to claim 3, characterized in that, The signal coupling capacitor and the fourth port are respectively connected to the two ends of the gating switch.

6. The photoelectric detection device according to any one of claims 1 to 5, characterized in that, The photodetector is a single-photon avalanche diode or a silicon photomultiplier tube.

7. The photoelectric detection device according to any one of claims 1 to 5, characterized in that, It also includes a signal processing circuit, the input of which is connected to the fourth port, for amplifying and / or shaping the pulse signal output by the photodetector.

8. The photoelectric detection device according to claim 7, characterized in that, The signal processing circuit includes: An amplifier, the input of which is connected to the fourth port; A signal comparator or LVDS interface driver, the input of which is connected in parallel to the output of the amplifier; The signal comparator or LVDS interface driver is configured to have different DC threshold levels to extract threshold-crossing information at different time points from the amplified pulse signal.

9. A multi-channel photoelectric detection system, characterized in that, The device comprises M groups, each containing N photoelectric detection devices according to any one of claims 1 to 8. All photoelectric detection devices share a second port and a third port. The N photoelectric detection devices in each group are connected in parallel and share a first port. The Nth photoelectric detection device in each group shares a fourth port. M is an integer greater than or equal to 2, and N is an integer greater than or equal to 1.

10. A lidar, characterized in that, Including the multi-channel photoelectric detection system according to claim 9.

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