Light detecting device and light detecting system

Abstract

A light detecting device according to an embodiment of the present disclosure comprises: a plurality of pixels each having a light receiving element, and including a first pixel and a second pixel each capable of outputting a first signal based on an electric current flowing through the light receiving element; a first switching circuit capable of switching a path of the first signal; and a plurality of converting circuits including a first converting circuit and a second converting circuit capable of converting the first signal, input via the first switching circuit, into a second signal, which is a digital signal. The first switching circuit is capable of outputting, to the first converting circuit or a converting circuit different from the first converting circuit, the first signal from the first pixel, and outputting, to the second converting circuit or a converting circuit different from the second converting circuit, the first signal from the second pixel.

Description

Optical detection device and optical detection system

[0001] The present disclosure relates to optical detection devices and optical detection systems.

[0002] A light receiving device has been proposed that includes a memory unit that stores correction values ​​(correction amounts) corresponding to pixel positions, and an in-plane delay correction unit that performs correction processing on a histogram created by a histogram creation unit based on the correction values ​​stored in the memory unit (Patent Document 1).

[0003] International Publication No. 2020 / 022137

[0004] In a device for detecting light, it is desirable to suppress a decrease in detection accuracy.

[0005] It is desirable to provide a light detection device that can suppress a decrease in detection accuracy.

[0006]

[0013] A photodetection device according to an embodiment of the present disclosure includes a plurality of pixels including a first pixel and a second pixel, each having a light-receiving element capable of receiving light and outputting a current, and each capable of outputting a first signal based on the current of the light-receiving element, a first switching circuit capable of switching the path of the first signal, and a plurality of conversion circuits including a first conversion circuit and a second conversion circuit capable of converting the first signal input via the first switching circuit into a second signal, which is a digital signal. The first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or a conversion circuit different from the first conversion circuit, and is capable of outputting the first signal from the second pixel to the second conversion circuit or a conversion circuit different from the second conversion circuit.

[0014] A photodetection system according to an embodiment of the present disclosure includes a light source capable of irradiating light onto an object, and a photodetection device that receives light from the object. The photodetector device includes a plurality of pixels including a first pixel and a second pixel, each having a light-receiving element capable of receiving light and outputting a current, and capable of outputting a first signal based on the current of the light-receiving element, a first switching circuit capable of switching the path of the first signal, and a plurality of conversion circuits including a first conversion circuit and a second conversion circuit capable of converting the first signal input via the first switching circuit into a second signal, which is a digital signal. The first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or a conversion circuit different from the first conversion circuit, and is capable of outputting the first signal from the second pixel to the second conversion circuit or a conversion circuit different from the second conversion circuit.

[0007] FIG. 1 is a block diagram illustrating an example of a schematic configuration of a photodetection system according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating an example of a configuration of a pixel of a photodetection device according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating another example of a configuration of a pixel of a photodetection device according to an embodiment of the present disclosure. FIG. 4 is a diagram illustrating an example of a configuration of a photodetection device according to an embodiment of the present disclosure. FIG. 5 is a diagram illustrating an example of a configuration of a signal processing unit of a photodetection device according to an embodiment of the present disclosure. FIG. 6 is a diagram illustrating an example of a configuration of a signal processing unit of a photodetection device according to an embodiment of the present disclosure. FIG. 7 is a diagram illustrating an example of signal processing by the signal processing unit of a photodetection device according to an embodiment of the present disclosure. FIG. 8 is a diagram illustrating an example of signal processing by the signal processing unit of a photodetection device according to an embodiment of the present disclosure. FIG. 9 is a diagram illustrating an example of operation of a photodetection device according to an embodiment of the present disclosure. FIG. 10 is a diagram illustrating an example of operation of a photodetection device according to an embodiment of the present disclosure. FIG. 11 is a diagram illustrating an example of operation of a photodetection device according to an embodiment of the present disclosure. FIG. 12 is a diagram illustrating an example of operation of a photodetection device according to an embodiment of the present disclosure. FIG. 13 is a diagram illustrating an example configuration of a photodetector according to an embodiment of the present disclosure. FIG. 14 is a diagram illustrating another example configuration of a photodetector according to an embodiment of the present disclosure. FIG. 15 is a diagram illustrating an example configuration of a switching circuit of a photodetector according to an embodiment of the present disclosure. FIG. 16 is a diagram illustrating another example configuration of a switching circuit of a photodetector according to an embodiment of the present disclosure. FIG. 17 is a diagram illustrating an example configuration of a photodetector according to Modification 1 of the present disclosure. FIG. 18 is a diagram illustrating an example configuration of a photodetector according to Modification 1 of the present disclosure. FIG. 19 is a diagram illustrating an example configuration of a photodetector according to Modification 2 of the present disclosure. FIG. 20 is a diagram illustrating an example configuration of a photodetector according to Modification 3 of the present disclosure. FIG. 21 is a diagram illustrating an example configuration of a photodetector according to Modification 4 of the present disclosure. FIG. 22 is a diagram illustrating an example configuration of a photodetector according to Modification 5 of the present disclosure. FIG. 23 is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 24 is an explanatory diagram illustrating an example of installation positions of an outside vehicle information detection unit and an imaging unit.

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order: 1. Embodiment 2. Modification 3. Usage example 4. Application example

[0009] 1 is a block diagram showing an example of a schematic configuration of a light detection system according to an embodiment of the present disclosure. The light detection system 300 includes a light detection device 1 and a light emitting device 2. The light detection device 1 and the light detection system 300 can be configured as a device capable of performing distance measurement, i.e., a distance measurement device or a distance measurement system. The light detection system 300 is configured to be able to perform distance measurement using, for example, a time-of-flight (TOF) method.

[0010] The photodetector 1 is a device capable of detecting incident light. The photodetector 1 has a plurality of pixels P including light-receiving elements, and is configured to receive incident light and generate a signal. The photodetector 1 is a device capable of receiving light and generating a signal, and can also be called a light-receiving device. The photodetector 1 can be configured as a distance measuring sensor, an image sensor, or the like capable of measuring distance using the TOF method.

[0011] The pixels P of the photodetector 1 include, for example, an avalanche photodiode (APD) as a light-receiving element and are configured to receive light and output a current. The light-receiving element (light-receiving unit) of each pixel P can be configured to generate a signal in response to receiving photons. The photodetector 1 generates a signal by receiving light that has passed through an optical system (not shown) including, for example, an optical lens.

[0012] The photodetector 1 is configured using, for example, a semiconductor substrate (for example, a Si (silicon) substrate, an SOI (silicon on insulator) substrate, or the like) on which light receiving elements of each pixel P are provided. The photodetector 1 has a region (pixel section 100) in which a plurality of pixels P are provided. As shown in the example in FIG. 1 , the photodetector 1 is provided with the pixel section 100 in which a plurality of pixels P are two-dimensionally arranged in a matrix. The pixel section 100 can also be said to be a pixel array in which a plurality of pixels P are arranged.

[0013] The light receiving element of each pixel P may be configured by a SPAD (single photon avalanche diode). The photodetector 1 captures incident light from a measurement object via an optical system including, for example, an optical lens. The light receiving element of the pixel P receives light from the measurement object (e.g., infrared light, visible light, etc.) and generates charges through photoelectric conversion, thereby generating a photocurrent.

[0014] The light emitting device 2 has a light source unit 200 and a control unit 220. The light source unit 200 is configured to be able to generate light (optical signals). The light source unit 200 has, for example, one or more light emitting elements and is configured to be able to irradiate light onto a measurement object. The light emitting element is an LD (Laser Diode), an LED (Light Emitting Diode), or the like, and can output light (infrared light, visible light, etc.) to the outside.

[0015] The light source unit 200 (light source) may, for example, generate laser light and emit the laser light to the outside. The light source unit 200 may be configured using a semiconductor laser element, for example, a vertical cavity surface emitting laser (VCSEL). The light emitting device 2 has a light source unit including a light emitting element (i.e., a light emitting region), and can also be called a light source device.

[0016] The control unit 220 is configured to be able to control the light source unit 200. The control unit 220 is a control circuit and is configured to be able to control the light emitting elements of the light source unit 200. The control unit 220 can also be said to be a drive unit (drive circuit) configured to be able to drive the light source unit 200 (or the light emitting elements). The control unit 220 is configured with a plurality of circuits including, for example, a timing generator, a DA conversion circuit (DAC: Digital to Analog Converter), an amplifier circuit, etc., and can control the operation of the light source unit 200.

[0017] The control unit 220 is configured to be able to control, for example, the current and voltage to the light emitting elements of the light source unit 200. The control unit 220 can supply the light source unit 200 with the current and voltage for driving the light emitting elements of the light source unit 200, and can control the light emission (for example, the light emission timing, the light emission duration, etc.) of the light emitting elements. The control unit 220 can also be called a light source control unit or a light source driving unit.

[0018] The light detection system 300 can irradiate a target with light (e.g., laser light) using the light source unit 200 and receive the light reflected by the target. In the light detection device 1, for example, reflected light (returned light) reflected by the target is incident on the pixel unit 100, and an electrical signal corresponding to the reception of the reflected light is detected. The electrical signal generated by receiving the reflected light from the target is a signal corresponding to the distance to the target.

[0019] The light detection system 300 transmits and receives light and can measure the distance to a measurement target. The light detection device 1 is configured, for example, to detect the distance to an object (subject) that is the measurement target for each pixel P and generate image data (distance image data) related to the distance to the object. The light detection device 1 can generate, for example, a depth map.

[0020] The light detection device 1 and the light detection system 300 can also be applied to a sensor capable of detecting an event, such as an event-driven sensor (called an EVS (Event Vision Sensor), an EDS (Event Driven Sensor), or a DVS (Dynamic Vision Sensor)). The light detection device 1 and the light detection system 300 can be applied to various electronic devices.

[0021] 1 , the photodetector 1 includes a pixel unit 100, a pixel control unit 110, a signal processing unit 120, and a control unit 150. At least a portion of the photodetector 1 and the light-emitting device 2 may be integrated. For example, a portion or all of the control unit 150 and the control unit 220 may be integrated. The light source unit 200 may be mounted on the photodetector 1 or provided outside the photodetector 1.

[0022] The pixel control unit 110 is configured to be able to control each pixel P of the pixel unit 100. The pixel control unit 110 is a control circuit and is configured by a plurality of circuits including, for example, a buffer, a shift register, an address decoder, etc. The pixel control unit 110 generates signals for controlling the pixels P and outputs them to each pixel P of the pixel unit 100. The pixel control unit 110 is controlled by the control unit 150 and controls the pixels P of the pixel unit 100.

[0023] The pixel control unit 110 generates signals for controlling the pixels P, such as signals for controlling a readout circuit of the pixels P, and supplies the signals to each pixel P. The pixel control unit 110 can control the reading out of pixel signals from each pixel P. The pixel control unit 110 can also be said to be a pixel driving unit (pixel driving circuit) configured to be able to drive each pixel P.

[0024] The control unit 150 is configured to be able to control each unit of the photodetector 1. The control unit 150 receives an externally provided clock, data instructing an operation mode, and the like, and can also output data such as internal information of the photodetector 1. The control unit 150 is a control circuit, and has, for example, a timing generator configured to be able to generate various timing signals.

[0025] The control unit 150 controls the driving of the pixel control unit 110, the signal processing unit 120, etc. based on various timing signals (pulse signals, clock signals, etc.) generated by the timing generator. The control unit 150 can include circuits such as a PLL (Phase Locked Loop) and a DAC (Digital to Analog Converter).

[0026] The control unit 150 is configured to, for example, supply a signal for controlling the control unit 220 to the control unit 220 and control the operation of the control unit 220. The control unit 150 can be configured to be able to control the generation process of pixel signals by the pixels P of the pixel unit 100, the timing of light irradiation by the light source unit 200, etc.

[0027] The signal processing unit 120 is a signal processing circuit configured to be able to perform signal processing. The signal processing unit 120 is configured with circuits that perform various types of signal processing on signals output from each pixel P. The signal processing unit 120 is configured to include an arithmetic circuit, a memory circuit, etc., and can perform various types of signal processing such as noise reduction processing, TD (Time to Digital) conversion processing, and counting (accumulation) processing.

[0028] The signal processing unit 120 is configured to acquire a signal from each pixel P and generate a signal related to the distance to the measurement target. For example, the signal processing unit 120 may perform various signal processing on the signal from each pixel P to generate and output distance image data representing the distance to the measurement target. The signal processing unit 120 and the control unit 150 may be configured integrally. The signal processing unit 120 and the control unit 150 may include a processor and a memory.

[0029] The signal processing unit 120 generates a signal (distance signal) indicating the distance to the measurement object based on the pixel signal. As an example, in the light detection system 300, the light source unit 200 repeatedly starts and stops emitting light, and repeatedly detects reflected light by the pixel P (i.e., light reflected from the measurement object). The signal processing unit 120 can generate and output image data (distance image data) including a distance signal for each pixel P by, for example, analyzing the pixel signals sequentially output from each pixel P through multiple distance measurements.

[0030] The pixel unit 100, pixel control unit 110, signal processing unit 120, control unit 150, etc. may be provided on a single substrate or may be provided separately on multiple substrates. The photodetector 1 may have, for example, a structure (a stacked structure) formed by stacking multiple semiconductor layers. Furthermore, at least one of the light source unit 200 and the control unit 220 may be provided on the same substrate as the pixel unit 100, etc.

[0031] 2 is a diagram illustrating an example of the configuration of a pixel of a photodetector according to an embodiment. A pixel P of the photodetector 1 includes a light-receiving element 10 and a readout circuit 20. For example, a readout circuit 20 is provided for each light-receiving element 10. Note that a readout circuit 20 may be provided for multiple light-receiving elements 10. The photodetector 1 may have a configuration in which multiple pixels P share one readout circuit 20.

[0032] The light receiving element 10 is configured to receive light and generate a signal. The light receiving element 10 is, for example, a SPAD (Single Photon Avalanche Diode) and has a multiplication region (multiplication section) capable of avalanche multiplication. The light receiving element 10 can convert incident photons into electric charges and output an electrical signal (signal S1 in FIG. 2 ) corresponding to the incident photons. The light receiving element 10 can also be referred to as a photoelectric conversion element (photoelectric conversion section) configured to be capable of photoelectrically converting light.

[0033] 2, the light receiving element 10 has one electrode, a cathode, electrically connected to a node N1 connected to the supply circuit 21 and the output circuit 25. The other electrode, an anode, of the light receiving element 10 is electrically connected to, for example, a wiring, an electrode, or the like to which a relatively low voltage is supplied.

[0034] 2, the anode of the light receiving element 10 is electrically connected to a potential line L2 serving as a power supply line. A voltage VSPAD is applied to the anode of the light receiving element 10 via the potential line L2 from a power supply unit (voltage source) capable of supplying voltage. The voltage VSPAD is, for example, a negative voltage.

[0035] The readout circuit 20 is configured to be able to output a signal based on the current of the light receiving element 10. The readout circuit 20 is configured to include circuits for reading out a signal based on the photocurrent flowing through the light receiving element 10, such as a supply circuit 21 and an output circuit 25. Note that the configuration of the readout circuit 20 is not limited to the example shown in the figure and can be changed as appropriate.

[0036] The supply circuit 21 is configured to be able to supply current and voltage to the light receiving element 10. The supply circuit 21 (supply unit) is electrically connected to the potential line L1 and is able to supply current and voltage to the light receiving element 10. The supply circuit 21 is configured, for example, by a current source that is able to supply current to the light receiving element 10. The potential line L1 is a wiring to which a predetermined potential (voltage) is applied. In the example shown in FIG. 2 , the potential line L1 is a power supply line to which a power supply voltage VH is applied.

[0037] The supply circuit 21 is, for example, configured with a transistor M1. The transistor M1 is, for example, a MOS transistor (MOSFET) having terminals of a gate, a source, and a drain. In the example shown in Fig. 2, the transistor M1 is a P-type transistor (for example, a PMOS transistor). One of the source and drain of the transistor M1, which serves as a current source, is electrically connected to a potential line L1 to which a power supply voltage VH is applied, and the other of the source and drain of the transistor M1 is electrically connected to the light receiving element 10.

[0038] The transistor M1 of the supply circuit 21 generates a current corresponding to the signal level of a signal input to its gate, and can supply the generated current to the light receiving element 10. The supply circuit 21 (supply unit) may be configured using a resistive element. The supply circuit 21 may also be configured by a switch that electrically connects or disconnects the potential line L1 and the light receiving element 10.

[0039] A voltage that is applied between the cathode and anode of the light receiving element 10 by the voltage supplied via the supply circuit 21 and the voltage VSPAD supplied by the potential line L2 can be applied, resulting in a potential difference that is larger than the breakdown voltage of the light receiving element 10. In other words, the potential difference across the light receiving element 10 can be set to a potential difference that is larger than the breakdown voltage.

[0040] When a reverse bias voltage greater than the breakdown voltage is applied to the light receiving element 10, the element 10 enters a state in which it can operate in Geiger mode. In Geiger mode, the light receiving element 10 may experience an avalanche multiplication phenomenon in response to incident photons, generating a pulsed current. In the pixel P, a signal S1 corresponding to the photocurrent flowing through the light receiving element 10 due to the incident photons is output to the output circuit 25.

[0041] For example, when avalanche multiplication occurs and the potential difference between the electrodes of the light-receiving element 10 is small, the supply circuit 21 supplies current to the light-receiving element 10. The supply circuit 21 recharges the light-receiving element 10, making it possible for the light-receiving element 10 to operate in Geiger mode again. The supply circuit 21 can recharge the light-receiving element 10 with electric charge and recharge the voltage of the light-receiving element 10.

[0042] The output circuit 25 is configured to generate a signal Sp1 based on the signal S1 generated by the light receiving element 10. The output circuit 25 can output the signal Sp1 as a voltage signal based on the current of the light receiving element 10. The output circuit 25 is configured using an inverter (INV), for example. The output circuit 25 has, for example, an input section 26 and an output section 27, and can output an inverted signal of the input signal.

[0043] 2, the output circuit 25 is configured with an INV circuit (inverter circuit). The INV circuit is configured, for example, with a PMOS transistor and an NMOS transistor connected in series between the potential line L1 and a reference potential line. The reference potential line is, for example, a wiring to which 0 V is applied as a GND voltage, i.e., a ground line (earth line).

[0044] The input section 26 of the output circuit 25 is electrically connected to, for example, the cathode of the light receiving element 10 and the supply circuit 21. In the example shown in Figure 2, the input section 26 of the output circuit 25 (i.e., the INV circuit) is electrically connected to a node N1 that connects the light receiving element 10 and the supply circuit 21.

[0045] The output circuit 25 receives the signal S1 from the light receiving element 10. The signal level of the signal S1, i.e., the voltage (potential) of the signal S1, varies depending on the current flowing through the light receiving element 10. For example, when the voltage of the signal S1 is higher than a threshold, the output circuit 25 outputs a low-level signal Sp1. When the voltage of the signal S1 is lower than the threshold, the output circuit 25 outputs a high-level signal Sp1.

[0046] 2, the INV circuit, which is the output circuit 25, transitions the voltage of the signal Sp1 from low to high when the voltage of the signal S1 becomes smaller than the threshold voltage of the INV circuit due to the reception of photons by the light receiving element 10. Furthermore, the output circuit 25 transitions the voltage of the signal Sp1 from high to low when the voltage of the signal S1 becomes larger than the threshold voltage of the INV circuit as the light receiving element 10 is recharged by the supply circuit 21.

[0047] The output circuit 25 can output the signal Sp1, which becomes a pulse signal, as a pixel signal to the signal processing unit 120 (see FIG. 1 ). In the photodetector 1, for example, the signal Sp1, which becomes a pulse signal based on the voltage of the signal S1, is output as a pixel signal by the readout circuit 20 to the signal processing unit 120.

[0048] The configuration of the output circuit 25 is not limited to the above example and can be changed as appropriate. The output circuit 25 may be configured with a buffer circuit, an AND circuit, a NAND circuit, an OR circuit, a NOR circuit, etc. The read circuit 20 may include a circuit that controls the supply circuit 21.

[0049] 3 is a diagram illustrating another example of the configuration of a pixel of a photodetector according to an embodiment. As shown in the example of FIG. 3, the readout circuit 20 may have a level conversion circuit 28 (level shifter). The readout circuit 20 is configured to include, for example, a level-down circuit (level-down unit) as the level conversion circuit 28, and converts the voltage level of the signal Sp1 before outputting it. Note that the output circuit 25 may be configured to include the level conversion circuit 28.

[0050] 4 is a diagram illustrating an example of the configuration of a photodetector according to an embodiment. The signal processing unit 120 of the photodetector 1 includes, for example, a switching circuit 121, a plurality of conversion circuits 125, and an arithmetic circuit 130, as shown in the example of FIG. 4. The switching circuit 121 is configured to be able to switch the path of a signal from a pixel P.

[0051] The switching circuit 121 is, for example, electrically connected between each pixel P of the pixel unit 100 and each conversion circuit 125, and is configured to be able to switch the transmission path of a signal output from the pixel P. The switching circuit 121 can be configured to be able to change the connection state between each pixel P and each conversion circuit 125. The switching circuit 121 can also be called a signal switching circuit or a path switching circuit.

[0052] The switching circuit 121 can switch the transmission path for each period (unit time) and transmit the pixel signal of each pixel P to each conversion circuit 125. The switching circuit 121 is configured by, for example, a multiplexer circuit (also called a selector), a switch circuit, a buffer circuit, etc.

[0053] The switching circuit 121 is configured to switch the signal path of the pixel signal (i.e., the signal Sp1) input from the pixel P at predetermined intervals (e.g., every frame or every subframe) and change the output destination of each pixel signal. As an example, the switching circuit 121 can use a multiplexer (MUX), a switch, or the like to control to which of the multiple conversion circuits 125 the pixel signal of the pixel P is output.

[0054] In the signal processing unit 120, the signal path is switched by the switching circuit 121, and for example, a conversion circuit 125 is set as an output destination of the pixel signal of each pixel P. The switching circuit 121 changes the signal path of the pixel signal Sp1 in a time-division manner (at each time interval) and outputs the signal Sp1 to the conversion circuit 125. It can also be said that the switching circuit 121 distributes the pixel signals input from the multiple pixels P of the pixel unit 100 to each conversion circuit 125.

[0055] The conversion circuit 125 is configured to be able to perform TD (Time to Digital) conversion and converts input pixel signals into digital signals. The conversion circuit 125 is provided, for example, for each pixel P or for each set of pixels P. The conversion circuit 125 is a TDC (Time to Digital Converter). The conversion circuit 125 is configured to be able to convert input pixel signals into digital signals related to the light reception timing of the pixel P.

[0056] The conversion circuit 125 is configured as a TD conversion circuit (TD conversion unit) using, for example, a flip-flop circuit, a counter circuit, etc. The conversion circuit 125 (conversion unit) is configured to convert, for example, a pixel signal, which is a pulse signal generated by the pixel P, into a digital signal corresponding to the elapsed time from when light is emitted by (the light-emitting element of) the light source unit 200 to when light is received by the light-receiving element 10 of the pixel P.

[0057] A pixel signal is input to the conversion circuit 125 from each pixel P of the pixel unit 100 via the switching circuit 121. The conversion circuit 125 performs TD conversion processing on the pixel signals, which become pulse signals sequentially read out from each pixel P. The signal Sp1, which is a pixel signal transmitted via the switching circuit 121, is subjected to TD conversion processing by the conversion circuit 125 and converted into a digital signal indicating, for example, the timing of receiving reflected light from the measurement object.

[0058] The conversion circuit 125 is configured to be able to output, as a converted pixel signal (signal Sp2), a digital signal corresponding to the time from the timing of light emission by the light source unit 200 to the timing of reception of reflected light (returned light) by the light receiving element 10. As an example, the conversion circuit 125 converts the pixel signal Sp1, which is a pulse signal, into the signal Sp2, which is a digital signal with a predetermined number of bits, and outputs it as a signal indicating the round-trip time of light (i.e., the time of flight).

[0059] The conversion circuit 125 may measure, for example, the time from the timing of light emission by the light source unit 200 to the timing of a transition (rising edge or falling edge) of a pixel signal corresponding to reception of reflected light as a count value, and generate a signal indicating the count value as a converted pixel signal. Based on the signal Sp1, the conversion circuit 125 may output, as a converted pixel signal, a signal Sp2 indicating a count value corresponding to the period from the start of irradiation of light onto the measurement object to the reception of reflected light from the measurement object.

[0060] In the signal processing unit 120, by the switching operation of the switching circuit 121 described above, for example, pixel signals from the same pixel P are transmitted to different paths and different conversion circuits 125 for each period and converted into digital signals. The pixel signals of each pixel P can be TD converted via different signal paths for each predetermined period and output to the arithmetic circuit 130.

[0061] The arithmetic circuit 130 is configured to acquire the pixel signals converted into digital signals and perform arithmetic processing. The arithmetic circuit 130 (arithmetic unit) is configured to include, for example, a logic circuit, a memory, etc. As an example, the arithmetic circuit 130 generates data regarding the light reception timing for each pixel P based on the pixel signals (i.e., the signal Sp2) output by each conversion circuit 125, and calculates the distance to the measurement target.

[0062] The arithmetic circuit 130 is configured to generate a histogram of the signal values ​​(i.e., count values) of the pixel signals for each pixel or for each predetermined number of pixels in each period (e.g., subframe) in which the signal path is set by the switching circuit 121. The arithmetic circuit 130 can, for example, integrate histograms obtained for each pixel in different periods and calculate the distance to the measurement target using the integrated histogram.

[0063] 4, the arithmetic circuit 130 includes a switching circuit 131 and a plurality of generation circuits 135. The switching circuit 131 is configured to be able to switch the path of the signal from the conversion circuit 125. The arithmetic circuit 130 includes, for example, the same number of generation circuits 135 as the number of conversion circuits 125. The switching circuit 131 can also be referred to as a signal switching circuit or a path switching circuit.

[0064] The switching circuit 131 is, for example, electrically connected between the plurality of conversion circuits 125 and the plurality of generation circuits 135, and is configured to be able to switch the path of the pixel signal transmitted from the conversion circuits 125. The switching circuit 131 can be configured to be able to change the connection state between each conversion circuit 125 and each generation circuit 135.

[0065] The switching circuit 131 can switch the transmission path every predetermined period (unit period) and transmit the pixel signal of each pixel P converted by each conversion circuit 125 to each generation circuit 135. The switching circuit 131 is configured by, for example, a multiplexer circuit, a switch circuit, a buffer circuit, etc.

[0066] The switching circuit 131 is configured to switch the signal path of the pixel signal (i.e., the signal Sp2) input via the conversion circuit 125 for each period (e.g., for each frame or subframe), and change the output destination of each pixel signal. As an example, the switching circuit 131 can use a multiplexer (MUX), a switch, or the like to control to which of the multiple generation circuits 135 the pixel signal of the pixel P is output.

[0067] In the signal processing unit 120, for example, a switching circuit 131 switches the signal path, and a generation circuit 135 is set as an output destination of the pixel signal of each pixel P. The switching circuit 131 changes the signal path of the pixel signal Sp2 to a time-division path, and outputs the signal Sp2 to the generation circuit 135. It can also be said that the switching circuit 131 distributes the pixel signals of each pixel P converted by the multiple conversion circuits 125 to the respective generation circuits 135.

[0068] The signal processing unit 120 is configured to, for example, set a pixel signal path in the switching circuit 121 as well as a pixel signal path in the switching circuit 131. As an example, the signal processing unit 120 can be configured to switch the signal path in the switching circuit 131 in conjunction with switching of the signal path in the switching circuit 121.

[0069] 5 and 6 are diagrams illustrating an example of the configuration of a signal processing unit of a photodetector according to an embodiment. Each of FIGS. 5 and 6 schematically illustrates the signal paths of pixel signals from six pixels P (referred to as pixels Pa to Pf) to six generation circuits 135 (referred to as generation circuits 135a to 135f). Also illustrated are six conversion circuits 125 (conversion circuits 125a to 125f) between each pixel P and each generation circuit 135.

[0070] Fig. 5 shows an example of a path setting (path setting A), and Fig. 6 shows another example of a path setting (path setting B). Note that the signal paths in the switching circuit 121 and the signal paths in the switching circuit 131 are not limited to the examples shown in Fig. 5 or 6, and can be set arbitrarily.

[0071] For example, in a certain period (e.g., the first subframe), the signal processing unit 120 sets a signal path in the switching circuit 121 and the switching circuit 131 as path setting A, as shown schematically by the dashed line in Fig. 5. Furthermore, in the next period (e.g., the second subframe), the signal processing unit 120 sets a signal path in the switching circuit 121 and the switching circuit 131 as path setting B, as shown schematically by the dashed line in Fig. 6.

[0072] 5 and 6 , the switching circuit 131 changes the signal path in the switching circuit 131 in accordance with the signal path in the switching circuit 121 so that, for example, pixel signals read out from the same pixel P for each period are input to the same generation circuit 135. The pixel signals output from the pixels P are transmitted to different paths and different conversion circuits 125 for each period, converted into digital signals, and transmitted to the same generation circuit 135 via the switching circuit 131.

[0073] 4 and 5, for example, includes an adder circuit, a multiplier circuit, a memory circuit, etc., and is configured as a histogram generation circuit (histogram generation unit) capable of generating a histogram of pixel signals. The generation circuit 135 is configured, for example, to generate a histogram of count values ​​corresponding to the signal values ​​of pixel signals, i.e., the round-trip time of light.

[0074] The generation circuit 135 can generate data relating to the correspondence between count values ​​corresponding to the round-trip time of light and the frequency of the count values ​​(i.e., the frequency (number) of the count values) as histogram data. As an example, the generation circuit 135 classifies the count values ​​into predetermined intervals (ranges), i.e., into bins (BINs), and generates histogram data showing the distribution of the count values ​​according to the distance to the measurement target.

[0075] The generation circuit 135 receives pixel signals from the same pixel P repeatedly during each period (e.g., subframe) via, for example, the switching circuit 131. The generation circuit 135 can collectively count multiple pixel signals (i.e., count values) measured during each period for each BIN and generate histogram data indicating the frequency (number) of the count values. For example, the count values ​​of pixels acquired via different signal paths for each predetermined period are integrated (summed) for each BIN to generate the histogram data.

[0076] The arithmetic circuit 130 is configured to be able to calculate the distance to the measurement target based on a peak value (maximum value) in a histogram of pixel signal values. For example, the arithmetic circuit 130 calculates the difference between the start time of light irradiation and the time of arrival of reflected light, i.e., the round-trip time (time of flight) of light, based on a count value (or BIN) indicating the peak value of frequency (frequency) in the histogram of pixel signals.

[0077] The arithmetic circuit 130 is configured to calculate (estimate) the distance between the light detection device 1 (or the light detection system 300) and the measurement object using, for example, the round-trip time calculated using the integrated histogram. As an example, the arithmetic circuit 130 calculates the distance to the object for each pixel P and generates a distance signal related to the distance to the object.

[0078] In the light detection system 300, the distance to the measurement object is determined based on the time it takes for light irradiated from the light source unit 200 to be reflected by the measurement object and reach the light detection device 1. The signal processing unit 120 can generate, for example, depth map data, distance image data including a distance signal for each pixel P, and output the data to the outside of the light detection device 1.

[0079] If the delay amount (i.e., delay time) differs in each path from each pixel to each TDC, skew occurs due to differences in propagation delay, and even for pixel signals that indicate the same light-receiving timing (i.e., reaction timing), there may be differences in the count values ​​after TD conversion. This may result in an error in the count value due to the propagation delay, and may reduce the distance measurement accuracy.

[0080] As described above, the photodetector 1 according to this embodiment is provided with the switching circuit 121. Therefore, it is possible to generate a histogram of pixel signals from the pixel P using a plurality of paths and the conversion circuit 125. The integrated histogram can be used to calculate the distance to the measurement target, making it possible to suppress a decrease in distance measurement accuracy.

[0081] 7 and 8 are diagrams for explaining an example of signal processing by the signal processing unit of the photodetector according to the embodiment. Fig. 7 shows an example of histograms generated by a certain generation circuit 135 (e.g., the generation circuit 135a corresponding to pixel Pa shown in Figs. 5 and 6 ) and another generation circuit 135 (e.g., the generation circuit 135b corresponding to pixel Pb shown in Figs. 5 and 6 ) among the multiple generation circuits 135 of the signal processing unit 120.

[0082] 7 and 8 show an example in which the light-receiving timing (i.e., the response timing of the light-receiving element 10) at pixel Pa and pixel Pb is the same. Also shown are distance measurement values ​​DP, which indicate count values ​​(i.e., BIN values) corresponding to the peak values ​​in each histogram, and skews Sa and Sb between the distance measurement values. These skews are caused by, for example, differences in propagation delay, and represent the difference (amount of deviation) between the distance measurement values.

[0083] The generation circuit 135 is configured to be able to generate an integrated histogram by integrating histograms obtained for each period in which a signal path is set by the switching circuit 121. In the example shown in Fig. 7, the generation circuit 135a generates histogram data D1 during a certain period, for example, during the period in which path setting A shown in Fig. 5 is set.

[0084] 7, the generation circuit 135a adds (integrates) histogram data D2 obtained during the next period, for example, the period during which path setting B shown in FIG. 6 is set, to histogram data D1 to generate histogram data D5. The generation circuit 135a can calculate the histogram data D5 by, for example, accumulating count values ​​(i.e., time information) that are pixel signals converted by the multiple conversion circuits 125 during the respective setting periods of path setting A and path setting B.

[0085] The generation circuit 135b generates histogram data D3 during a certain period, i.e., during the period when route setting A is set. The generation circuit 135b also sums (adds) histogram data D4 obtained during the next period, i.e., during the period when route setting B is set, to the histogram data D3 to generate histogram data D6.

[0086] The generation circuit 135b can calculate the histogram data D6 by, for example, accumulating count values, which are pixel signals converted by the multiple conversion circuits 125, during the respective setting periods of the route setting A and the route setting B. In the example shown in Fig. 7, a skew Sa occurs between the distance measurements DP1a to DP4a obtained from the histogram data D1 to D4 due to the difference in propagation delay of each route.

[0087] 8 also shows distance measurement values ​​DP1a to DP4a and distance measurement values ​​DP1b to DP4b including variations according to VT (Voltage Temperature) conditions (i.e., characteristic variations due to voltage and temperature). The distance measurement values ​​DP1a to DP4a and DP1b to DP4b are measured under mutually different VT conditions (VT condition C Ａ , VT condition C Ｂ The measured distance values ​​DP1a to DP4a change to the measured distance values ​​DP1b to DP4b depending on the voltage and temperature, and a skew Sb occurs between the measured distance values ​​DP1b to DP4b.

[0088] The arithmetic circuit 130 of the signal processing unit 120 is configured to be able to generate the integrated histogram data D5 and D6 as described above using the generation circuits 135a and 135b. For example, as shown in the example of Fig. 7, the arithmetic circuit 130 can generate histogram data D5 (and histogram data D6) that has the average value of the count value for route setting A and the count value for route setting B as the centroid value of the histogram.

[0089] In this manner, in this embodiment, an integrated histogram is generated, making it possible to reduce the skew between distance measurements. In the example shown in Figures 7 and 8, the skew between distance measurement value DP5a and distance measurement value DP6a obtained from histogram data D5 and D6 can be set to skew Sa', which is smaller than skew Sa. This makes it possible to reduce errors in the count values ​​caused by differences in propagation delay.

[0090] Furthermore, even when the voltage (e.g., power supply voltage) or temperature changes, the skew between the distance measurements can be suppressed, as shown by the outline arrows in Fig. 8. In the example shown in Fig. 8, the skew between the distance measurements DP5a and DP6a when the V (voltage) and T (temperature) conditions change can be set to a skew Sb' that is smaller than the skew Sb.

[0091] As described above, the photodetector 1 according to this embodiment can reduce skew caused by differences in propagation delay, thereby improving distance measurement accuracy. This embodiment can also reduce the amount of skew fluctuation associated with voltage and temperature changes. Therefore, even when correcting distance measurement values ​​by shifting the histogram after its creation, the correction process can be performed with high accuracy.

[0092] Furthermore, in this embodiment, compared to the case where a large number of memory circuits are provided for storing a large number of correction values ​​for each VT condition, it is possible to reduce the chip area of ​​the photodetector 1. Furthermore, it is possible to avoid an increase in manufacturing process time and manufacturing costs due to the need to obtain a large number of correction values ​​for each VT condition in advance.

[0093] In this embodiment, as described above, skew can be reduced by utilizing path switching. Therefore, the size of the driver (buffer) provided in each path may be reduced, and the wiring width may be reduced. This allows the circuit area of ​​the switching circuit 121, the conversion circuit 125, etc. to be reduced, and also makes it possible to reduce power consumption.

[0094] 9 to 12 are diagrams for explaining an example of the operation of the photodetector according to the embodiment. Fig. 10 is a timing chart showing an example of the operation in the case of the path setting A shown in Fig. 9. Fig. 12 is a timing chart showing an example of the operation in the case of the path setting B shown in Fig. 11. Note that the path settings shown in the figures are merely examples and can be changed as appropriate.

[0095] 9 and 11 respectively show four pixels P (pixel Pa to pixel Pd), four conversion circuits 125 (conversion circuits 125a to 125d), and four generation circuits 135 (generation circuits 135a to 135d). Note that delay times TpdA to TpdD and delay times TpdA' to TpdD' shown in FIGS. 9 to 12 are delay amounts (i.e., signal delay amounts) in the respective paths from each pixel P to each conversion circuit 125.

[0096] 10 and 12, on the same time axis, the signal Sp1 (signal Sp1a) output from pixel Pa, the signal Sp1 (signal Sp1b) output from pixel Pb, the signal Sp1 (signal Sp1a', signal Sp1b') input to conversion circuits 125a and 125b, and the BIN values ​​counted in generation circuits 135a and 135b are illustrated.

[0097] 10 and 12 also show, on the same time axis, a signal SLT indicating the timing of light emission by the light source unit 200. Figures 10 and 12 show an example in which the light reception timing (i.e., reaction timing) of pixel Pa and pixel Pb is the same. Figure 10 is a timing chart for the period of the first subframe, and Figure 11 is a timing chart for the period of the second subframe after the first subframe.

[0098] At time t1 in the first subframe period, the light source unit 200 irradiates the measurement object with light based on the light emission timing signal SLT. At time t2, the pixels Pa and Pb change the voltages of the signals Sp1a and Sp1b from low to high in response to receiving light from the measurement object. The pixels Pa and Pb output the signals Sp1a and Sp1b as pulse signals.

[0099] By setting path setting A in the first subframe, a signal Sp1a' obtained by delaying the signal Sp1a by a delay time TpdA is input to the conversion circuit 125a from pixel Pa via the switching circuit 121. The signal Sp1a' is TD converted by the conversion circuit 125a and then output to the generation circuit 135a via the switching circuit 131.

[0100] Furthermore, a signal Sp1b' obtained by delaying the signal Sp1b by a delay time Tp dB is input to the conversion circuit 125b from the pixel Pb via the switching circuit 121. The signal Sp1b' is TD converted by the conversion circuit 125b and then output to the generation circuit 135b via the switching circuit 131.

[0101] In the signal processing unit 120, the signals Sp1a' and Sp1b' are converted into different count values ​​and counted into different BINs depending on the difference between the delay times TpdA and TpdB (i.e., the propagation delay difference). In the example shown in Fig. 10, the generation circuit 135a counts the signal Sp1a' as BIN "4," and the generation circuit 135b counts the signal Sp1b' as BIN "5."

[0102] 12 , at time t11 in the second subframe period, the light source unit 200 irradiates the measurement object with light in response to the light emission timing signal SLT. At time t12, the pixels Pa and Pb change the voltages of the signals Sp1a and Sp1b from low to high in response to receiving light from the measurement object. The pixels Pa and Pb output the signals Sp1a and Sp1b, which are pulse signals.

[0103] By setting path setting B in the second subframe, a signal Sp1b' obtained by delaying the signal Sp1b by a delay time TpdB' is input to the conversion circuit 125a from pixel Pb via the switching circuit 121. The signal Sp1b' is TD converted by the conversion circuit 125a and then output to the generation circuit 135b via the switching circuit 131.

[0104] Furthermore, the conversion circuit 125b receives a signal Sp1a' obtained by delaying the signal Sp1a by a delay time TpdA' from pixel Pa via the switching circuit 121. The signal Sp1a' is TD converted by the conversion circuit 125b and then output to the generation circuit 135a via the switching circuit 131.

[0105] In the signal processing unit 120, the signals Sp1a' and Sp1b' are converted into different count values ​​and counted into different BINs depending on the difference (propagation delay difference) between the delay times TpdA' and TpdB'. In the example shown in Fig. 12, the generation circuit 135a counts the signal Sp1a' as BIN "5", and the generation circuit 135b counts the signal Sp1b' as BIN "4".

[0106] In this way, the signal processing unit 120 of the photodetector 1 can add up the count values ​​(time information) for each subframe using different paths and different conversion circuits 125 to generate an integrated histogram. Using the integrated histogram makes it possible to accurately measure the distance to the measurement target. This improves the detection accuracy of the distance signal (distance information).

[0107] 13 is a diagram illustrating an example of the configuration of a photodetector according to an embodiment. The conversion circuit 125 includes a plurality of flip-flops C1, as shown in the example of FIG. 13. The counter 126 (counter circuit) is configured to count pulses of a signal CLK, which is an input clock signal, and output a signal Sout indicating the count value to each flip-flop C1 (flip-flop circuit).

[0108] As an example, the counter 126 is provided in common to the multiple conversion circuits 125 (conversion circuits 125a to 125n). In the example shown in Fig. 13, one counter 126 is provided for the conversion circuits 125a to 125n. The counter 126 is connected in common to each conversion circuit 125, and can generate a signal Sout used for TD conversion and supply it to each conversion circuit 125. Note that the conversion circuit 125 may be configured to include the counter 126.

[0109] To the flip-flop C1, for example, a signal Sp1 is input from the pixel P via the switching circuit 121, and a signal Sout is input from the counter 126. As an example, the flip-flop C1 converts the signal Sp1, which is a pulse signal, into a signal Sp2 related to the timing of light reception at the pixel P in accordance with the signal Sout indicating the count value. The conversion circuit 125 includes a plurality of flip-flops C1, and can convert the signal Sp1, which is a pulse signal, into a signal Sp2, which is a digital signal with a predetermined number of bits, and output the signal Sp2.

[0110] 13, the conversion circuit 125n is located close to the counter 126, and the conversion circuit 125a is located far from the counter 126. The delay time (propagation delay) of the signal Sout from the counter 126 to the conversion circuit 125a is longer (larger) than the delay time of the signal Sout from the counter 126 to the conversion circuit 125n.

[0111] If the delay amount (i.e., delay time) on each path from the counter to each TDC is different, skew due to differences in propagation delay may occur, and even for pixel signals indicating the same light reception timing (reaction timing), there is a risk of differences in the count values ​​after TD conversion.The deviation in the count values ​​due to propagation delay may occur, and distance measurement accuracy may decrease.

[0112] As described above, the photodetector 1 according to this embodiment is provided with the switching circuit 121, which allows a histogram of the signal from the pixel P to be generated using a plurality of paths and the conversion circuit 125. This makes it possible to suppress deviations (errors) in the count value caused by delay time differences in the signal Sout and suppress deterioration in distance measurement accuracy.

[0113] 14 is a diagram illustrating another example of the configuration of the photodetector according to the embodiment. The conversion circuit 125 may include a flip-flop C2 (flip-flops C2a to C2n in FIG. 14). The flip-flop C2 is configured to hold (sample) the signal Sp1 of the pixel P in accordance with the input signal CLK and output the signal Sp1 to the flip-flop C1.

[0114] The flip-flop C2 is configured to sample the signal Sp1 in synchronization with the signal CLK, which is a clock signal, and output the sampled signal to the flip-flop C1. The data signal is exchanged between the flip-flop C1 and the flip-flop C2, and timing adjustments can be performed. The flip-flop C2 can also be considered a synchronization circuit (synchronization unit).

[0115] 14, a difference between the propagation delay (delay time) of the signal CLK to the flip-flop C2a and the propagation delay of the signal CLK to the flip-flop C2n may cause a discrepancy in the count value, which may result in a deterioration in distance measurement accuracy.

[0116] In this embodiment, the provision of the switching circuit 121 makes it possible to generate a histogram of the signal of the pixel P using a plurality of paths and the conversion circuit 125. This makes it possible to suppress deviations in the count value caused by delay time differences in the signal CLK and to suppress deterioration in distance measurement accuracy.

[0117] 15 is a diagram illustrating an example of the configuration of a switching circuit of a photodetector according to an embodiment. The switching circuit 121 includes, for example, a plurality of buffers 122 and a plurality of switches SW, and is configured to be able to switch the path of a signal from a pixel P, as in the example shown in FIG. 15 . By switching the connection state of each switch SW in the switching circuit 121, it is possible to change the path of the pixel signal of each pixel P.

[0118] 16 is a diagram illustrating another example of the configuration of the switching circuit of the photodetector according to the embodiment. In the photodetector 1, a plurality of conversion circuits 125 are provided corresponding to the number of pixel signals transmitted via the switching circuit 121. As an example, the conversion circuit 125 may be provided for each predetermined number of pixels P. The number of conversion circuits 125 may be less than the number of pixels P in the pixel unit 100. Note that the conversion circuit 125 may be provided for each pixel P.

[0119] [Functions and Effects] The photodetector according to this embodiment includes a plurality of pixels (pixels P) including a first pixel and a second pixel, each of which has a light-receiving element (light-receiving element 10) capable of receiving light and outputting a current and is capable of outputting a first signal (e.g., signal Sp1) based on the current of the light-receiving element, a first switching circuit (switching circuit 121) capable of switching the path of the first signal, and a plurality of conversion circuits (conversion circuits 125) including a first conversion circuit and a second conversion circuit capable of converting the first signal input via the first switching circuit into a second signal (signal Sp2), which is a digital signal. The first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or a conversion circuit different from the first conversion circuit, and is capable of outputting the first signal from the second pixel to the second conversion circuit or a conversion circuit different from the second conversion circuit.

[0120] The photodetector 1 according to this embodiment includes a switching circuit 121 that can switch signal paths. The switching circuit 121 is configured to output, for example, the signal Sp1 from pixel Pa to conversion circuit 125a or a conversion circuit 125 different from conversion circuit 125a, and to output the signal Sp1 from pixel Pb to conversion circuit 125b or a conversion circuit 125 different from conversion circuit 125b. This makes it possible to reduce skew caused by propagation delay differences. This makes it possible to realize a photodetector that can suppress degradation of detection accuracy.

[0121] Next, a modified example of the present disclosure will be described. In the following, the same components as those in the above embodiment will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0122] 17 and 18 are diagrams for explaining a configuration example of a photodetector according to a first modification of the present disclosure. In the above-described embodiment, a configuration example of the photodetector 1 has been described, but the configuration of the photodetector 1 is not limited to the above-described example. For example, the configuration of the switching circuit 121 of the photodetector 1 is not limited to the example shown in the drawings and can be modified as appropriate.

[0123] 17 , the switching circuit 121 has a plurality of demultiplexers 123 and a plurality of tri-state buffers 124, and is configured to be able to switch the path of a signal from the pixel P. For example, the signal processing unit 120 can change the path of a pixel signal from each pixel P by controlling each demultiplexer 123 (DEMUX) and each tri-state buffer 124 of the switching circuit 121.

[0124] 18 , the switching circuit 121 may be configured using a plurality of buffers 122 and a plurality of multiplexers 127. The multiplexer 127 is configured to be able to select and output some of the signals input from each of the plurality of buffers 122. The multiplexer 127 can also be called a selection circuit (selection unit). By controlling each multiplexer 127 of the switching circuit 121, the path of the pixel signal of each pixel P can be changed.

[0125] (2-2. Modification 2) FIG. 19 is a diagram for explaining a configuration example of a photodetector according to Modification 2. As shown in the example of FIG. 19, the arithmetic circuit 130 of the signal processing unit 120 may have a plurality of memories 136. The memory 136 is a storage unit (storage circuit) and is configured, for example, by an SRAM (Static Random Access Memory). The memory 136 is configured to be able to store histogram data. The arithmetic circuit 130 has memories 136 in a number corresponding to the number of generation circuits 135, for example.

[0126] 19 , the switching circuit 131 is electrically connected between each generation circuit 135 and each memory 136, and is configured to be able to switch the path of a signal from the generation circuit 135. The signal processing unit 120 is configured, for example, to set the signal path in the switching circuit 131 together with the signal path in the switching circuit 121. As an example, the signal processing unit 120 can be configured to switch the transmission path in the switching circuit 131 in conjunction with switching the transmission path in the switching circuit 121.

[0127] The switching circuit 131 changes the signal path in the switching circuit 131 in accordance with the signal path in the switching circuit 121, for example, so that the count values ​​of the same pixel P are input to and stored in the same memory 136. The pixel signal output from the pixel P is transmitted to a different path and a different conversion circuit 125 for each period, converted into a count value, and transmitted to the same memory 136 via the generation circuit 135 and the switching circuit 131.

[0128] The arithmetic circuit 130 is configured to store (accumulate) in the memory 136 histogram data obtained for each period during which the signal path is set by the switching circuit 121, and generate integrated histogram data. This modification also makes it possible to suppress a decrease in detection accuracy. The same effects as those of the above-described embodiment can be obtained.

[0129] (2-3. Modification 3) Fig. 20 is a diagram for explaining a configuration example of a photodetector according to Modification 3. At least one of the switching circuit 131 and the memory 136 may be provided outside the photodetector 1. In the example shown in Fig. 20, the switching circuit 131 and the memory 136 are provided on a chip 3. The chip 3 is a semiconductor chip, such as an application processor (AP).

[0130] 20 , the photodetector 1 includes an interface circuit 160. The interface circuit 160 (interface unit) is configured to be able to transmit an input signal. The interface circuit 160 can be configured to output, for example, the histogram data generated by the generation circuit 135 to the chip 3.

[0131] The chip 3 is configured to generate integrated histogram data by, for example, storing (retaining) histogram data obtained for each predetermined period (e.g., subframe) in the memory 136. In this modified example, it is also possible to suppress a decrease in detection accuracy. The light detection system 300 may be configured to include the chip 3.

[0132] (2-4. Modification 4) FIG. 21 is a diagram illustrating an example configuration of a photodetector according to Modification 4. The arithmetic circuit 130 may include an adder circuit 137. The adder circuit 137 (adder) is configured to be able to perform addition processing of signals Sp2 (i.e., count values) input from a plurality of conversion circuits 125. The generation circuit 135 receives the added signal Sp2 via the adder circuit 137, for example. The generation circuit 135 can generate histogram data using the signal Sp2 added by the adder circuit 137.

[0133] (2-5. Modification 5) Fig. 22 is a diagram illustrating a configuration example of a photodetector according to Modification 5. The light receiving element 10, readout circuit 20, etc. of each pixel P of the photodetector 1 may be provided separately on multiple substrates (or semiconductor layers). For example, the photodetector 1 may have a layered structure formed by stacking multiple substrates.

[0134] As an example, the photodetector 1 may be configured by stacking a substrate 101 and a substrate 102. For example, the light receiving element 10 for each pixel P may be disposed on the substrate 101, and the readout circuit 20 for each pixel P may be disposed on the substrate 102. The pixel control unit 110, the signal processing unit 120, the control unit 150, and the like described above may be provided on the substrate 102, for example.

[0135] 3. Usage Examples The above-described light detection device 1 and light detection system 300 can be used in various cases for sensing light such as visible light, infrared light, ultraviolet light, and X-rays, for example, as described below.・Devices for taking images for viewing purposes, such as digital cameras and mobile devices with camera functions. ・Devices for traffic purposes, such as in-vehicle sensors that take images of the front, rear, surroundings, and interior of a car for safe driving such as automatic stopping, and for recognizing the driver's state, surveillance cameras that monitor moving vehicles and roads, and distance measuring sensors that measure distances between vehicles. ・Devices for home appliances such as televisions, refrigerators, and air conditioners that take images of user gestures and operate the device according to those gestures. ・Devices for medical and healthcare purposes, such as endoscopes and devices that take images of blood vessels by receiving infrared light. ・Devices for security purposes, such as surveillance cameras for crime prevention and cameras for person authentication. ・Devices for beauty purposes, such as skin measuring devices that take images of the skin and microscopes that take images of the scalp. ・Devices for sports purposes, such as action cameras and wearable cameras for sports, etc. ・Devices for agricultural purposes, such as cameras to monitor the condition of fields and crops.

[0136] 4. Application Examples (Application Examples to Mobile Bodies) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0137] FIG. 23 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0138] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 23, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0139] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0140] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0141] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0142] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0143] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0144] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0145] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0146] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0147] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 23, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0148] FIG. 24 is a diagram showing an example of the installation position of the imaging unit 12031.

[0149] In FIG. 24 , the vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as the imaging unit 12031.

[0150] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The forward images acquired by the imaging units 12101 and 12105 are mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0151] 24 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0152] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0153] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on driver operation.

[0154] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0155] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0156] An example of a mobile object control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the image capturing unit 12031 of the above-described configuration. Specifically, for example, the light detection device 1 can be applied to the image capturing unit 12031. By applying the technology according to the present disclosure to the image capturing unit 12031, a high-resolution captured image can be obtained, and high-precision control using the captured image can be performed in the mobile object control system.

[0157] Although the present disclosure has been described above by giving embodiments, modifications, use examples, and application examples, the present technology is not limited to the above-described embodiments, etc., and various modifications are possible. For example, although the modifications described above have been described as modifications of the above-described embodiments, the configurations of the modifications can be combined as appropriate.

[0158] According to an embodiment of the present disclosure, a photodetector includes a plurality of pixels including a first pixel and a second pixel, each of which has a light-receiving element capable of receiving light and outputting a current, and each of which can output a first signal based on the current of the light-receiving element; a first switching circuit capable of switching the path of the first signal; and a plurality of conversion circuits including a first conversion circuit and a second conversion circuit capable of converting the first signal input via the first switching circuit into a second signal, which is a digital signal. The first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or a conversion circuit different from the first conversion circuit, and is capable of outputting the first signal from the second pixel to the second conversion circuit or a conversion circuit different from the second conversion circuit. This makes it possible to realize a photodetector that can suppress a decrease in detection accuracy.

[0159] Note that the effects described in this specification are merely examples and are not limited to those described, and other effects may also be present. Furthermore, the present disclosure may also have the following configuration: (1) A photodetection device comprising: a plurality of pixels including a first pixel and a second pixel, each having a light-receiving element capable of receiving light and outputting a current, and each capable of outputting a first signal based on the current of the light-receiving element; a first switching circuit capable of switching a path of the first signal; and a plurality of conversion circuits including a first conversion circuit and a second conversion circuit capable of converting the first signal input via the first switching circuit into a second signal, which is a digital signal, wherein the first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or a conversion circuit different from the first conversion circuit, and is capable of outputting the first signal from the second pixel to the second conversion circuit or a conversion circuit different from the second conversion circuit. (2) The photodetector according to (1), wherein the plurality of conversion circuits include the first conversion circuit, the second conversion circuit, and a third conversion circuit, and the first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or the second conversion circuit, and is capable of outputting the first signal from the second pixel to the second conversion circuit or the third conversion circuit. (3) The photodetector according to (1) or (2), wherein the conversion circuit is capable of converting the first signal into the second signal related to light reception timing. (4) The photodetector according to any one of (1) to (3), wherein the conversion circuit is a TDC (Time to Digital Converter). (5) The photodetector device according to any one of (1) to (4), wherein the first switching circuit is capable of performing a first operation of outputting the first signal of the first pixel to the first conversion circuit and outputting the first signal of the second pixel to the second conversion circuit, and a second operation of outputting the first signal of the first pixel to the conversion circuit different from the first conversion circuit and outputting the first signal of the second pixel to the conversion circuit different from the second conversion circuit.(6) The photodetector according to (5), wherein the first switching circuit is capable of performing one of the first operation and the second operation and then performing the other of the first operation and the second operation. (7) The photodetector according to any one of (1) to (6), further comprising an arithmetic circuit capable of generating first data regarding a light reception timing of the first pixel, based on the second signal of the first pixel converted by the first conversion circuit and the second signal of the first pixel converted by a conversion circuit different from the first conversion circuit. (8) The photodetector according to (7), wherein the arithmetic circuit is capable of generating the first data based on the second signal of the first pixel converted by the first conversion circuit in a first period and the second signal of the first pixel converted by a conversion circuit different from the first conversion circuit in a second period. (9) The photodetector according to (7) or (8), wherein the arithmetic circuit is capable of generating second data regarding a light reception timing of the second pixel, based on the second signal of the second pixel converted by the second conversion circuit and the second signal of the second pixel converted by a conversion circuit different from the second conversion circuit. (10) The photodetector according to (9), wherein the arithmetic circuit is capable of generating the second data, based on the second signal of the second pixel converted by the second conversion circuit in a first period and the second signal of the second pixel converted by the conversion circuit different from the second conversion circuit in a second period. (11) The photodetector according to any one of (1) to (10), further comprising a second switching circuit capable of switching a path of the second signal. (12) The photodetector according to (11), further comprising: a first generation circuit capable of generating first data relating to a timing at which the first pixel receives light, based on the second signal of the first pixel input via the second switching circuit; and a second generation circuit capable of generating second data relating to a timing at which the second pixel receives light, based on the second signal of the second pixel input via the second switching circuit.(13) The photodetector device according to (12), wherein the second switching circuit is capable of outputting the second signal of the first pixel converted by the first conversion circuit or the conversion circuit different from the first conversion circuit to the first generation circuit, and is capable of outputting the second signal of the second pixel converted by the second conversion circuit or the conversion circuit different from the second conversion circuit to the second generation circuit. (14) The photodetector device according to (12) or (13), wherein the second switching circuit is capable of performing a first operation of outputting the second signal of the first pixel converted by the first conversion circuit to the first generation circuit and outputting the second signal of the second pixel converted by the second conversion circuit to the second generation circuit, and a second operation of outputting the second signal of the first pixel converted by the conversion circuit different from the first conversion circuit to the first generation circuit and outputting the second signal of the second pixel converted by the conversion circuit different from the second conversion circuit to the second generation circuit. (15) The photodetector according to (14), wherein the second switching circuit is capable of performing one of the first operation and the second operation and then performing the other of the first operation and the second operation. (16) The photodetector according to any one of (1) to (15), wherein the light-receiving element is an avalanche photodiode. (17) The photodetector according to any one of (1) to (16), further comprising: a first substrate having the light-receiving element; and a second substrate having the first switching circuit and the conversion circuit and stacked on the first substrate. (18) The photodetector according to (17), wherein the pixel has a readout circuit provided on the second substrate, and the readout circuit is capable of outputting the first signal based on a current of the light-receiving element.(19) A photodetection system comprising: a light source capable of irradiating light onto an object; and a photodetection device that receives light from the object, wherein the photodetection device comprises a plurality of pixels including a first pixel and a second pixel, each having a light-receiving element capable of receiving light and outputting a current, and each capable of outputting a first signal based on the current of the light-receiving element; a first switching circuit that can switch the path of the first signal; and a plurality of conversion circuits including a first conversion circuit and a second conversion circuit that can convert the first signal input via the first switching circuit into a second signal that is a digital signal, wherein the first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or to a conversion circuit different from the first conversion circuit, and is capable of outputting the first signal from the second pixel to the second conversion circuit or to a conversion circuit different from the second conversion circuit.

[0160] This application claims priority based on Japanese Patent Application No. 2024-110031, filed on July 9, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0161] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

a plurality of pixels including a first pixel and a second pixel, each having a light receiving element capable of receiving light and outputting a current, and each capable of outputting a first signal based on the current of the light receiving element; a first switching circuit capable of switching a path of the first signal; a plurality of conversion circuits including a first conversion circuit and a second conversion circuit capable of converting the first signal input via the first switching circuit into a second signal which is a digital signal; Equipped with The first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or the conversion circuit different from the first conversion circuit, and outputting the first signal from the second pixel to the second conversion circuit or the conversion circuit different from the second conversion circuit. Light detection device. 　 the plurality of conversion circuits include the first conversion circuit, the second conversion circuit, and a third conversion circuit; The first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or the second conversion circuit, and is also capable of outputting the first signal from the second pixel to the second conversion circuit or the third conversion circuit. The photodetector device according to claim 1 . 　 The conversion circuit is capable of converting the first signal into the second signal related to the light receiving timing. The photodetector device according to claim 1 . 　 The conversion circuit is a TDC (Time to Digital Converter). The photodetector device according to claim 1 . 　 The first switching circuit includes: a first operation of outputting the first signal of the first pixel to the first conversion circuit and outputting the first signal of the second pixel to the second conversion circuit; a second operation of outputting the first signal of the first pixel to the conversion circuit different from the first conversion circuit and outputting the first signal of the second pixel to the conversion circuit different from the second conversion circuit; The photodetector device according to claim 1 . 　 The first switching circuit is capable of performing one of the first operation and the second operation and then performing the other of the first operation and the second operation.

6. The photodetector according to claim 5. 　 The image pickup device further includes an arithmetic circuit capable of generating first data relating to a light receiving timing of the first pixel based on the second signal of the first pixel converted by the first conversion circuit and the second signal of the first pixel converted by a conversion circuit different from the first conversion circuit. The photodetector device according to claim 1 . 　 The arithmetic circuit is capable of generating the first data based on the second signal of the first pixel converted by the first conversion circuit in a first period and the second signal of the first pixel converted by the conversion circuit different from the first conversion circuit in a second period. The photodetector device according to claim 7 . 　 The arithmetic circuit is capable of generating second data regarding a light receiving timing of the second pixel based on the second signal of the second pixel converted by the second conversion circuit and the second signal of the second pixel converted by the conversion circuit different from the second conversion circuit. The photodetector device according to claim 7 . 　 The arithmetic circuit is capable of generating the second data based on the second signal of the second pixel converted by the second conversion circuit in a first period and the second signal of the second pixel converted by the conversion circuit different from the second conversion circuit in a second period. The photodetector device according to claim 9 . 　 a second switching circuit capable of switching the path of the second signal; The photodetector device according to claim 1 . 　 a first generation circuit capable of generating first data relating to a light receiving timing of the first pixel based on the second signal of the first pixel input via the second switching circuit; a second generation circuit capable of generating second data relating to a light receiving timing of the second pixel based on the second signal of the second pixel input via the second switching circuit; Further equipped The optical detection device according to claim 11 . 　 The second switching circuit is capable of outputting the second signal of the first pixel, which has been converted by the first conversion circuit or a conversion circuit different from the first conversion circuit, to the first generation circuit, and is also capable of outputting the second signal of the second pixel, which has been converted by the second conversion circuit or a conversion circuit different from the second conversion circuit, to the second generation circuit. The optical detection device according to claim 12. 　 The second switching circuit includes: a first operation of outputting the second signal of the first pixel converted by the first conversion circuit to the first generation circuit and outputting the second signal of the second pixel converted by the second conversion circuit to the second generation circuit; a second operation of outputting the second signal of the first pixel, which has been converted by a conversion circuit different from the first conversion circuit, to the first generation circuit, and outputting the second signal of the second pixel, which has been converted by a conversion circuit different from the second conversion circuit, to the second generation circuit. The optical detection device according to claim 12. 　 The second switching circuit is capable of performing one of the first operation and the second operation and then performing the other of the first operation and the second operation.

15. The optical detection device of claim 14. 　 The light receiving element is an avalanche photodiode. The photodetector device according to claim 1 . 　 a first substrate having the light receiving element; a second substrate having the first switching circuit and the conversion circuit and stacked on the first substrate; Further equipped The photodetector device according to claim 1 . 　 the pixel has a readout circuit provided on the second substrate, The readout circuit is capable of outputting the first signal based on a current of the light receiving element.

18. The optical detection device of claim 17. 　 a light source capable of irradiating light onto an object; a light detection device that receives light from the object; Equipped with The photodetector device a plurality of pixels including a first pixel and a second pixel, each having a light receiving element capable of receiving light and outputting a current, and each capable of outputting a first signal based on the current of the light receiving element; a first switching circuit capable of switching a path of the first signal; a plurality of conversion circuits including a first conversion circuit and a second conversion circuit capable of converting the first signal input via the first switching circuit into a second signal which is a digital signal; and The first switching circuit is capable of outputting the first signal from the first pixel to the first conversion circuit or the conversion circuit different from the first conversion circuit, and outputting the first signal from the second pixel to the second conversion circuit or the conversion circuit different from the second conversion circuit. Optical detection system.

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