Light detection device and light detection system

Abstract

To provide a light detection device capable of improving detection performance.SOLUTION: A light detection device according to one embodiment of the present disclosure comprises: a light receiving element capable of receiving light and outputting an electric current; and a first output circuit having a P-type transistor, an N-type transistor, and a resistor element electrically connected in series between the first power line and the reference potential line, and capable of outputting a first signal based on the current of the light receiving element.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to light detection devices and systems. [Background technology]

[0002] 2. Description of the Related Art A light detecting device has been proposed that includes a plurality of pixels each having a light receiving element configured using a SPAD (Single Photon Avalanche Diode) (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-24138 A Summary of the Invention [Problem to be solved by the invention]

[0004] In optical detection devices, it is desirable to improve detection performance.

[0005] It is desirable to provide a light detection device that has good detection performance. [Means for solving the problem]

[0006] An optical detection device according to one embodiment of the present disclosure includes a photodetector capable of receiving light and outputting a current, and a first output circuit having a P-type transistor, an N-type transistor, and a resistor element electrically connected in series between a first power supply line and a reference potential line, and capable of outputting a first signal based on the current of the photodetector. An optical detection system according to an embodiment of the present disclosure includes a light source capable of irradiating an object with light, and an optical detection device that receives light from the object. The optical detection device includes a light receiving element capable of receiving light and outputting a current, and a first output circuit having a P-type transistor, an N-type transistor, and a resistor electrically connected in series between a first power supply line and a reference potential line, and capable of outputting a first signal based on the current of the light receiving element. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of a schematic configuration of a light detection system according to an embodiment of the present disclosure. [Diagram 2] 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. [Diagram 3] FIG. 3 is a timing chart illustrating an example of the operation of the photodetector according to the embodiment of the present disclosure. [Figure 4] FIG. 4 is a timing chart illustrating an example of the operation of the photodetector according to the embodiment of the present disclosure. [Diagram 5] FIG. 5 is a diagram for explaining an example of the operation of the photodetector according to the embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram illustrating a configuration example of a light detection device according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating a configuration example of a light detection device according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram illustrating a configuration example of a light detection device according to an embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram illustrating another configuration example of a photodetector according to an embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram illustrating another configuration example of a photodetector according to an embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram illustrating another configuration example of a photodetector according to an embodiment of the present disclosure. [Figure 12A]FIG. 12A is a diagram for explaining a configuration example of a light detection device according to Modification 1 of the present disclosure. [Figure 12B] FIG. 12B is a diagram for explaining a configuration example of the photodetector according to the first modification of the present disclosure. [Figure 13] FIG. 13 is a diagram for explaining a configuration example of a light detection device according to Modification 2 of the present disclosure. [Figure 14A] FIG. 14A is a diagram for explaining another configuration example of the photodetector according to the second modification of the present disclosure. [Figure 14B] FIG. 14B is a diagram for explaining another configuration example of the photodetector according to the second modification of the present disclosure. [Figure 15] FIG. 15 is a diagram for explaining a configuration example of a light detection device according to the third modification of the present disclosure. [Figure 16] FIG. 16 is a diagram for explaining a configuration example of a light detection device according to the third modification of the present disclosure. [Figure 17] FIG. 17 is a diagram for explaining a configuration example of a light detection device according to the fourth modification of the present disclosure. [Figure 18] FIG. 18 is a diagram for explaining a configuration example of a light detection device according to the fourth modification of the present disclosure. [Figure 19] FIG. 19 is a diagram for explaining a configuration example of a light detection device according to the fifth modification of the present disclosure. [Figure 20] FIG. 20 is a block diagram showing an example of a schematic configuration of a vehicle control system. [Figure 21] FIG. 21 is an explanatory diagram showing an example of the installation positions of the vehicle outside information detection unit and the imaging unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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. Variations 3. Usage example 4. Application Examples

[0009] <1. Preferred embodiment> 1 is a 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 200 includes a light detection device 1, a light source control unit 210, and a light source 220. The light detection device 1 is a device capable of detecting incident light. The light detection device 1 has a plurality of pixels P including light receiving elements, and is configured to receive incident light and generate a signal.

[0010] The light receiving element of the pixel P of the light detection device 1 is, for example, an APD (Avalanche Photo Diode) and is 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 a photon. The light detection device 1 receives light that has passed through an optical system (not shown) including an optical lens, for example, and generates a signal.

[0011] The photodetection device 1 is configured using, for example, a semiconductor substrate (e.g., a silicon substrate) on which a plurality of pixels P are provided. As an example, the photodetection device 1 has a region (pixel section 100) in which the plurality of pixels P are two-dimensionally arranged in a matrix. The pixel section 100 of the photodetection device 1 is a pixel array in which the plurality of pixels P are arranged.

[0012] The light receiving element of each pixel P may be composed of a SPAD (single photon avalanche diode). The light detection device 1 captures incident light from a measurement object via an optical system including an optical lens. The light receiving element receives light from the measurement object (e.g., infrared light, visible light, etc.) and generates charges by photoelectric conversion, thereby generating a photocurrent.

[0013] The light detection device 1 can be configured as a distance measurement sensor, an image sensor, etc. The light detection device 1 is a device capable of performing distance measurement, and is configured to perform distance measurement by a Time Of Flight (TOF) method, for example. The light detection device 1 is applied as a distance measurement sensor capable of measuring distance by the TOF method, for example.

[0014] The light source 220 is configured to generate light (optical signal). The light source 220 has, for example, a plurality of light emitting elements, and is configured to be able to irradiate light onto a measurement target. The light emitting elements are, for example, LD (Laser Diode), LED (Light Emitting Diode), etc., and can output light (infrared light, visible light, etc.) to the outside.

[0015] In the light source 220, a plurality of light emitting elements may be arranged two-dimensionally in a matrix. As an example, the light source 220 (light source unit) may generate laser light and emit the laser light to the outside. The light source 220 may be configured using a semiconductor laser element, for example, a vertical cavity surface emitting laser (VCSEL).

[0016] The light source control unit 210 is configured to be able to control the light source 220. The light source control unit 210 is a drive unit (drive circuit) and configured to drive the light source 220. The light source control unit 210 is configured by a plurality of circuits including, for example, a DA conversion circuit (DAC: Digital to Analog Converter), an amplifier circuit, and the like, and can control the operation of the light source 220. The light source control unit 210 is configured to be able to control, for example, the current and voltage to the light emitting element of the light source 220.

[0017] The light source control unit 210 can supply the light source 220 with a current and a voltage for driving each light emitting element of the light source 220, and control light emission by the light source 220 (e.g., light emission timing, light emission time, etc.). The light source control unit 210 can also be said to be a light source driving unit configured to be able to drive the light source 220 (its light emitting elements). Note that the light source 220 and a part or all of the light source control unit 210 may be configured integrally as a light source device (light source unit).

[0018] The light detection system 200 can irradiate a measurement object with light (e.g., laser light) using a light source 220 and receive the light reflected by the measurement object. In the light detection device 1, for example, reflected light (return light) reflected by the measurement object 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 measurement object is a signal corresponding to the distance to the measurement object.

[0019] A light detection system 200 including the light detection device 1 can transmit and receive light and measure the distance to a measurement target. The light detection device 1 is configured to be able to detect the distance to an object (subject) that is the measurement target for each pixel P, for example, 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 can also be applied as a sensor capable of detecting an event, for example, an event-driven sensor (called an EVS (Event Vision Sensor), an EDS (Event Driven Sensor), a DVS (Dynamic Vision Sensor), etc.). The light detection device 1 and the light detection system 200 can be applied to various electronic devices.

[0021] 1, the photodetector 1 includes a pixel unit 100, a pixel control unit 111, a signal processing unit 112, and a control unit 113. The photodetector 1 may include a light source control unit 210. The light source 220 may be mounted on the photodetector 1 or may be provided outside the photodetector 1.

[0022] The pixel control unit 111 is configured to be able to control each pixel P of the pixel unit 100. The pixel control unit 111 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 111 generates a signal for controlling the pixel P, and outputs the signal to each pixel P of the pixel unit 100. The pixel control unit 111 is controlled by the control unit 113, and controls the pixel P of the pixel unit 100.

[0023] The pixel control unit 111 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 111 can control reading out pixel signals from each pixel P. The pixel control unit 111 can also be called a pixel driving unit configured to be able to drive each pixel P. The pixel control unit 111 and the control unit 113 can also be called a pixel control unit together.

[0024] The control unit 113 is configured to be able to control each unit of the photodetector 1. The control unit 113 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 113 is a control circuit, and has, for example, a timing generator configured to be able to generate various timing signals.

[0025] The control unit 113 performs drive control of the pixel control unit 111 and the signal processing unit 112, etc., based on various timing signals (pulse signals, clock signals, etc.) generated by a timing generator. The control unit 113 can include circuits such as a PLL (Phase Locked Loop), a DAC (Digital to Analog Converter), etc.

[0026] The control unit 113 is configured to supply a signal for controlling the light source control unit 210 to the light source control unit 210 and control the operation of the light source control unit 210. The control unit 113 can be configured to be capable of controlling the generation process of a pixel signal by the pixel P of the pixel unit 100, the timing of light irradiation by the light source 220, and the like.

[0027] The signal processing unit 112 is a signal processing circuit and is configured to be able to execute signal processing. The signal processing unit 112 is configured with circuits that perform various types of signal processing on signals output from each pixel P. The signal processing unit 112 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 112 is configured to acquire a signal from each pixel P, and generate and output a signal related to the distance to the measurement target. For example, the signal processing unit 112 may perform various signal processing on the signal from each pixel, and generate and output distance image data indicating the distance to the measurement target. The signal processing unit 112 and the control unit 113 may be configured integrally. The signal processing unit 112 and the control unit 113 may include a processor and a memory.

[0029] 1, the signal processing unit 112 has, for example, a conversion unit 70 and a calculation unit 80. Note that the signal processing unit 112 may have a pulse shaping circuit configured to shape a pixel signal that becomes a pulse signal read out from the pixel P. The pulse shaping circuit may be provided for each pixel P or for each set of multiple pixels P, for example.

[0030] The conversion unit 70 is configured to be able to convert an input pixel signal into a digital signal related to the timing of light reception at the pixel P. The conversion unit 70 is configured, for example, by a TDC (Time to Digital Converter) circuit. The conversion unit 70 is configured, for example, to convert a pixel signal, which is a pulse signal generated by the pixel P, into a digital signal corresponding to the elapsed time from when the light source 220 emits light to when the light receiving element of the pixel P receives light.

[0031] The conversion unit 70 is configured using a flip-flop circuit, a delay circuit (e.g., a delay buffer), a counter circuit, etc. The conversion unit 70 is a TD conversion unit (TD conversion circuit), and is provided, for example, for each pixel P or for each set of pixels P. Pixel signals that become pulse signals sequentially read out from each pixel P are subjected to, for example, TD conversion processing by the conversion unit 70, and are converted into digital signals that indicate the timing of receiving reflected light from the measurement target.

[0032] The conversion unit 70 (conversion circuit) can output, as a converted pixel signal, a digital signal corresponding to the time from when light is emitted by the light source 220 to when the reflected light (returned light) is received by the light receiving element. As an example, the conversion unit 70 converts the pixel signal, which is a pulse signal, into 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 flight time).

[0033] The conversion unit 70 may measure the time from the start of light irradiation by the light source 220 to the transition timing (rising edge or falling edge) of the pixel signal corresponding to the reception of the reflected light, and generate a signal indicating the count value as the converted pixel signal. Based on the pulse signal output from the pixel P, the conversion unit 70 may output a signal indicating a count value corresponding to the period from the start of light irradiation of the measurement object to the reception of the reflected light from the measurement object as the converted pixel signal.

[0034] In the light detection system 200, for example, the light source 220 repeatedly emits and stops emitting light, and the pixel P repeatedly detects reflected light (returned light). In the light detection device 1, pixel signals sequentially output from each pixel P by multiple distance measurements are each converted into a digital signal by conversion processing in the conversion unit 70.

[0035] The calculation unit 80 is configured to acquire pixel signals of the pixels P and perform signal processing. The calculation unit 80 is configured to generate a signal related to the distance to a measurement object (distance signal) based on the pixel signals converted by the conversion unit 70, for example. The calculation unit 80 can generate and output image data including a distance signal for each pixel P (distance image data) by analyzing the pixel signals of each pixel P.

[0036] The calculation unit 80 has, for example, a histogram generation unit 85, and is configured to be able to generate a histogram of the pixel signal, which is a digital signal converted by the conversion unit 70. The histogram generation unit 85 (histogram generation circuit) is configured, for example, to generate, for each pixel P, a histogram of the signal value of the pixel signal, i.e., the count value corresponding to the round-trip time of light.

[0037] The histogram generating unit 85 can generate data on the correspondence between the count value corresponding to the round trip time of light and the frequency (number) of the count value as histogram data, and store it in an internal memory or the like of the signal processing unit 112. For example, the histogram generating unit 85 classifies the count values ​​for each predetermined section (range), i.e., for each bin (BIN), and generates histogram data showing the distribution of the count values ​​according to the distance to the measurement target.

[0038] The calculation unit 80 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 calculation unit 80 calculates (estimates) the difference between the start time of light irradiation and the arrival time of reflected light, that is, the round trip time (time of flight) of light, based on the pixel signal value (count value) whose frequency in the histogram of pixel signals indicates a peak value.

[0039] The calculation unit 80 is configured to calculate the distance between the light detection device 1 and the measurement object using, for example, the calculated round trip time. The calculation unit 80 calculates the distance to the object for each pixel P and generates a distance signal related to the distance to the object. The distance to the measurement object is obtained based on the time it takes for light irradiated from the light source 220 to be reflected by the measurement object and reach the light detection device 1. The signal processing unit 112 can generate distance image data including the distance signal for each pixel P using the calculation unit 80 and output it to the outside of the light detection device 1.

[0040] The pixel section 100, pixel control section 111, signal processing section 112, control section 113, etc. may be provided on one substrate, or may be provided separately on multiple substrates. The photodetector 1 may have a structure (a laminated structure) formed by stacking multiple substrates. Some or all of the pixel control section 111, signal processing section 112, and control section 113 may be integrally configured.

[0041] 2 is a diagram showing an example of the configuration of a pixel of a photodetector according to an embodiment. A pixel P of the photodetector 1 has a light receiving element 10 (light receiving element) and a readout circuit 20. For example, the readout circuit 20 is provided for each light receiving element 10. The 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.

[0042] The light receiving element 10 is configured to receive light and generate a signal. The light receiving element 10 is 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 a signal S1 that is an electrical signal corresponding to the incident photons. The light receiving element 10 can also be called a photoelectric conversion element (photoelectric conversion section) configured to be capable of photoelectrically converting light.

[0043] 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 includes circuits for reading out a signal based on the photocurrent flowing through the light receiving element 10, such as a supply unit 30, a first output circuit 40, a second output circuit 50, and the like.

[0044] The supply unit 30 is configured to be able to supply current and voltage to the light receiving element 10. The supply unit 30 (supply circuit) is electrically connected to a power supply line L1a to which a power supply voltage VDDH is applied, and is able to supply current and voltage to the light receiving element 10. The supply unit 30 is a charging unit (charging circuit), and is configured, for example, by a current source that is able to supply current to the light receiving element 10.

[0045] The supply unit 30 may be configured using a P-type transistor (e.g., a PMOS transistor), for example. For example, one of the source and drain of the transistor of the supply unit 30 is electrically connected to a power supply line to which a power supply voltage VDDH is applied, and the other of the source and drain of the transistor M3 is electrically connected to the light receiving element 10. The supply unit 30 may be configured using a resistive element. The supply unit 30 may also be configured by a switch that electrically connects or disconnects the power supply line and the light receiving element 10.

[0046] The supply unit 30 supplies a current to the light receiving element 10, for example, when avalanche multiplication occurs and the potential difference between the electrodes of the light receiving element 10 is smaller than the breakdown voltage. The supply unit 30 recharges the light receiving element 10, and makes the light receiving element 10 capable of operating in the Geiger mode again. The supply unit 30 can also be called a recharge unit (recharge circuit). The supply unit 30 can recharge the light receiving element 10 with an electric charge and recharge the voltage of the light receiving element 10.

[0047] The light receiving element 10 is electrically connected to, for example, a power supply line, an electrode, etc. capable of supplying a predetermined voltage. In the example shown in Fig. 2, one electrode of the light receiving element 10, which is a cathode, is electrically connected to a power supply line L1a to which a power supply voltage VDDH is supplied via a supply unit 30. The other electrode of the light receiving element 10, which is an anode, is connected to the reference potential line side.

[0048] The 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 power supply voltage is supplied. In the example shown in Fig. 2, a power supply voltage (voltage VSP in Fig. 2) is applied to the anode of the light receiving element 10 via a power supply line L1b from a power supply unit (voltage source) capable of supplying a voltage (current). The voltage VSP is, for example, a negative voltage.

[0049] A voltage that is a potential difference larger than the breakdown voltage of the light receiving element 10 can be applied between the cathode and anode of the light receiving element 10 by the voltage supplied via the supply unit 30 and the voltage VSP supplied by the power supply line L1b. That is, the potential difference across the light receiving element 10 can be set to a potential difference larger than the breakdown voltage.

[0050] When a reverse bias voltage larger than the breakdown voltage is applied to the light receiving element 10, the light receiving element 10 is operable in the Geiger mode. In the light receiving element 10 in the Geiger mode, an avalanche multiplication phenomenon occurs in response to the incidence of a photon, and a pulse-like current may be generated. In the pixel P, a signal S1 corresponding to the photocurrent flowing through the light receiving element 10 due to the incidence of a photon is output to the first output circuit 40.

[0051] The first output circuit 40 is configured to generate a signal S11 based on the signal S1 generated by the light receiving element 10. In the example shown in Fig. 2, the first output circuit 40 includes an inverter. The first output circuit 40 is configured using a transistor M1, a transistor M2, and a resistor element R electrically connected in series. The first output circuit 40 has an input section 41 and an output section 42, and can output an inverted signal of an input signal.

[0052] The second output circuit 50 is configured to generate a signal S12 based on the signal S11 output by the first output circuit 40. In the example shown in Fig. 2, the second output circuit 50 includes an inverter. The second output circuit 50 is configured using a transistor M3 and a transistor M4 electrically connected in series. The second output circuit 50 has an input section 51 and an output section 52, and can output an inverted signal of an input signal.

[0053] Each of the transistors M1 to M4 is a MOS transistor (MOSFET) having a gate, a source, and a drain terminal. The transistors M1 and M3 are N-type transistors (NMOS transistors in FIG. 2). The transistors M2 and M4 are P-type transistors (PMOS transistors in FIG. 2).

[0054] The gates of the transistors M1 and M2 are electrically connected to each other and constitute an input section 41. The gates of the transistors M1 and M2 are electrically connected to the light receiving element 10. The source of the transistor M2 is electrically connected to a power supply line L1a to which a power supply voltage VDDH is supplied. The drains of the transistors M1 and M2 are electrically connected to each other and constitute an output section 42.

[0055] The source of the transistor M1 is electrically connected to the reference potential line L2b. The reference potential line L2b is, for example, a ground line. A specific potential, for example, a GND potential (ground potential), is supplied to the reference potential line L2b. In the example shown in FIG. 2, the reference potential line L2b is a wiring to which a voltage VSS (for example, 0 V) ​​is applied.

[0056] The gates of the transistors M3 and M4 are electrically connected to each other and form an input section 51. The gates of the transistors M3 and M4 are electrically connected to the first output circuit 40. The source of the transistor M4 is electrically connected to a power supply line L2a to which a power supply voltage VDDL is supplied. The power supply voltage VDDL is, for example, a voltage lower than the power supply voltage VDDH.

[0057] The source of the transistor M3 is electrically connected to the reference potential line L2b. The drain of the transistor M3 and the drain of the transistor M4 are electrically connected to each other to form an output section 52. The above-mentioned first output circuit 40 is, for example, a first-stage output circuit and can also be called a first amplifier circuit. The second output circuit 50 is, for example, a second-stage output circuit and can also be called a second amplifier circuit. The first output circuit 40 and the second output circuit 50 may each be configured by an AND circuit, an OR circuit, or the like.

[0058] The input section 41 of the first output circuit 40 is electrically connected to, for example, the cathode of the light receiving element 10 and the supply section 30. The output section 42 of the first output circuit 40 is electrically connected to the input section 51 of the second output circuit 50. In the example shown in FIG. 2, the input section 41 of the first output circuit 40 is electrically connected to a node N1 that connects the light receiving element 10 and the supply section 30. In addition, the output section 42 of the first output circuit 40 is electrically connected to a node N2 that connects the first output circuit 40 and the second output circuit 50.

[0059] 2, node N1 is a part of the input section 41 of the first output circuit 40, and serves as an input node of the first output circuit 40. Node N2 is a part of the input section 51 of the second output circuit 50, and serves as an input node of the second output circuit 50. Node N2 is also a part of the output section 42 of the first output circuit 40, and serves as an output node of the first output circuit 40. Node N1 and node N2 can each be considered as a connection node.

[0060] The transistor M1, the transistor M2, and the resistor R of the first output circuit 40 are electrically connected between the power supply line L1a and the reference potential line L2b. The resistor R is electrically connected in series between the transistor M1 and the transistor M2. In the example shown in FIG. 2, the resistor R is electrically connected between the transistor M2 and the node N2.

[0061] The resistive element R is, for example, a resistor (resistive member) such as a poly resistor or a metal resistor. The resistive element R may be formed using polysilicon (Poly-Si) or a metal material such as tungsten (W) or titanium (Ti). The resistive element R may be a resistive element (substrate resistor) provided on a semiconductor substrate. For example, the resistive element R (substrate resistor) may be formed by doping (adding) impurities to a silicon substrate. The resistive element R may be made of a metal compound (metal oxide, metal nitride, etc.) or other materials.

[0062] The resistance element R may be configured using a transistor. The resistance element R may be configured using a transistor having a gate to which a predetermined voltage (bias voltage) is supplied. The resistance element R may be configured using a diode-connected transistor. The resistance element R may have a configuration in which a plurality of resistors are connected in series or in parallel.

[0063] The first output circuit 40 receives a signal S1 from the light receiving element 10. The signal level of the signal S1, i.e., the voltage (electric potential) of the signal S1, changes 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 first output circuit 40 outputs a low-level signal S11. Also, when the voltage of the signal S1 is lower than the threshold, the first output circuit 40 outputs a high-level signal S11. The first output circuit 40 can output the signal S11 based on the voltage of the signal S1 to the second output circuit 50.

[0064] The second output circuit 50 receives the signal S11 from the first output circuit 40. The signal level of the signal S12 output by the second output circuit 50, i.e., the voltage of the signal S12, changes according to the signal S11. For example, when the voltage of the signal S11 is higher than a threshold, the second output circuit 50 outputs a low-level signal S12. When the voltage of the signal S11 is lower than a threshold, the second output circuit 50 outputs a high-level signal S12. The second output circuit 50 can output the signal S12, which is a pulse signal based on the voltage of the signal S11, to the signal line L10.

[0065] 2, the inverter serving as the first output circuit 40 transitions the voltage of the signal S11 from a low level to a high level when the voltage of the signal S1 becomes smaller than the inverter's threshold voltage due to reception of a photon by the light receiving element 10. In this case, the inverter serving as the second output circuit 50 transitions the voltage of the signal S12 from a high level to a low level when the voltage of the signal S11 becomes larger than the inverter's threshold voltage.

[0066] Furthermore, when the voltage of the signal S1 becomes larger than the threshold voltage of the inverter as the light receiving element 10 is recharged by the supply unit 30, the first output circuit 40 transitions the voltage of the signal S11 from high level to low level. In this case, when the voltage of the signal S11 becomes smaller than the threshold voltage of the inverter, the second output circuit 50 transitions the voltage of the signal S12 from low level to high level. In this way, the second output circuit 50 can output the signal S12, which becomes a pulse signal, as a pixel signal to the signal processing unit 112 (see FIG. 1) via the signal line L10.

[0067] The time from the voltage drop between the electrodes of the light receiving element 10 due to the reception of photons to the voltage rise between the electrodes of the light receiving element 10 due to recharging is the dead time. The dead time can also be said to be the period during which quenching and recharging are performed. The dead time is, for example, the period from the rising timing to the falling timing of the signal S11, which is the output signal of the first output circuit 40, that is, the time corresponding to the high-level pulse width of the signal S11.

[0068] 2, the dead time corresponds to, for example, the period from when the voltage of the signal S11 exceeds the threshold voltage of the second output circuit 50 until the voltage of the signal S11 falls to or below the threshold voltage of the second output circuit 50. If the dead time is long, the photodetector 1 may not be able to perform photodetection with high accuracy.

[0069] Therefore, in the photodetector 1 according to this embodiment, the first output circuit 40 has a resistive element R electrically connected in series to the transistor M1 and the transistor M2. This makes it possible to shorten the transition time of the signal S11 of the first output circuit 40. For example, it is possible to shorten the period until the voltage of the signal S11 drops to or below the threshold voltage of the second output circuit 50. It is possible to shorten the dead time and suppress a decrease in the accuracy of photodetection. The photodetector 1 according to this embodiment will be further described below.

[0070] Fig. 3 is a timing chart for explaining an example of the operation of the photodetector according to the embodiment. An example of the operation of the photodetector 1 will be explained with reference to the timing chart of Fig. 3 and Fig. 2 etc. Fig. 3 shows a schematic diagram of a signal S1, a current I1 flowing through a resistive element R, a signal S11, and a signal S12 on the same time axis.

[0071] In the period from time t1 to time t2, when photons are incident on the light receiving element 10 and avalanche multiplication occurs, the current flowing through the light receiving element 10 increases and the potential difference between the cathode and anode of the light receiving element 10 decreases. In the example shown in Figures 2 and 3, the cathode voltage of the light receiving element 10 decreases and the voltage of the signal S1 input to the first output circuit 40 decreases.

[0072] During the period from time t1 to time t2, the potential difference between the electrodes of the light receiving element 10 becomes smaller than the breakdown voltage, and thus avalanche multiplication is stopped (quenched). The first output circuit 40 transitions the voltage of the signal S11 from a low level to a high level as the voltage of the signal S1 drops. The second output circuit 50 transitions the voltage of the signal S12 from a high level to a low level in response to the voltage of the signal S11.

[0073] In the period from time t2 to time t3, when a current (recharge current) is supplied from the supply unit 30 to the light receiving element 10, the potential difference between the electrodes of the light receiving element 10 increases. In the example shown in Figures 2 and 3, the cathode voltage of the light receiving element 10, i.e., the voltage of the signal S1, increases.

[0074] When the potential difference between the electrodes of the light receiving element 10 becomes larger than the breakdown voltage, the light receiving element 10 becomes capable of operating in the Geiger mode again. The first output circuit 40 changes the voltage of the signal S11 from high level to low level as the voltage of the signal S1 increases. The second output circuit 50 changes the voltage of the signal S12 from low level to high level as the voltage of the signal S11 decreases.

[0075] If the first output circuit 40 does not have the resistive element R, the time required for the voltage of the signal S11 to drop below the threshold voltage Vt of the second output circuit 50 may be longer, as shown typically by the dashed line A1 in Fig. 3. The dead time may be increased due to the delay time (amount of delay) in the first output circuit 40. For this reason, for example, as shown typically by the dashed line A2 in Fig. 4, the signal S12 that becomes a pulse signal in response to reception of light from the measurement target may not be appropriately generated, and accurate light detection may not be possible.

[0076] As described above, the photodetector 1 according to this embodiment is provided with the resistive element R. Therefore, as shown by the solid line in Fig. 3, it is possible to shorten the time until the voltage of the signal S11 drops to or below the threshold voltage Vt of the second output circuit 50. By providing the resistive element R in the first output circuit 40, the current I1, which becomes the through current, flows through the resistive element R, and it is possible to accelerate the voltage drop of the signal S11. It is possible to shorten the time until the voltage of the signal S11 reaches (changes to) the threshold voltage Vt of the second output circuit 50.

[0077] In this manner, in this embodiment, by providing the resistive element R, it is possible to realize a short dead time. As shown by the solid line in Fig. 4, the signal S12 that becomes a pulse signal can be appropriately generated, and light detection can be performed with high accuracy. It is possible to appropriately measure the distance to a plurality of nearby objects.

[0078] Furthermore, in the photodetector 1, the resistive element R is electrically connected between the transistor M1 and the transistor M2. This makes it possible to prevent the gate-source voltages of the transistors M1 and M2 from decreasing, thereby making it possible to effectively reduce the dead time.

[0079] Fig. 5 is a diagram for explaining an example of the operation of the photodetector according to the embodiment. Fig. 5(A) shows an example of a case where distance measurement of a person to be measured is performed using an electronic device (e.g., a smartphone) to which the photodetector 1 is applied. Fig. 5(B) shows a schematic example of histogram data obtained by the photodetector 1.

[0080] As described above, the photodetector 1 has a resistive element R, and can achieve a low dead time. This allows the photodetector 1 to capture reflected light (signal light) from a person behind an automatic door that is a semitransparent body such as glass, for example, as shown in Figs. 5(A) and (B), and generate histogram data. In the example shown in Fig. 5(B), the photodetector 1 can properly measure the distance to the automatic door and the distance to the person. It is possible to realize a photodetector with high discrimination performance.

[0081] Fig. 6 is a diagram showing a configuration example of a photodetector according to an embodiment. The photodetector 1 may have a layered structure in which a plurality of substrates are stacked. In the example shown in Figs. 6(A) and (B), the photodetector 1 has a first substrate 101 and a second substrate 102. The photodetector 1 has a layered structure in which the first substrate 101 and the second substrate 102 are stacked. The first substrate 101 and the second substrate 102 are stacked on top of each other.

[0082] The multiple substrates (first substrate 101 and second substrate 102 in FIG. 6) of the photodetector 1 are composed of semiconductor substrates (e.g., silicon substrate, SOI substrate, etc.). As an example, the first substrate 101 and the second substrate 102 are bonded together by bonding between metal electrodes made of Cu, i.e., Cu-Cu bonding. The first substrate 101 and the second substrate 102 may be connected via a TSV (Through Silicon Via). The circuit of the first substrate 101 and the circuit of the second substrate 102 are electrically connected, for example, via a through electrode. Note that the multiple substrates may be stacked using bumps (e.g., microbumps).

[0083] Fig. 6(A) shows an example of a planar configuration of the first substrate 101 of the light detection device 1. Fig. 6(B) shows an example of a planar configuration of the second substrate 102 of the light detection device 1. For example, the light receiving elements 10 of each pixel P of the pixel section 100 are provided on the first substrate 101. On the first substrate 101, as in the example shown in Fig. 6(A), a plurality of light receiving elements 10 may be arranged in a horizontal direction (row direction) which is a first direction, and a vertical direction (column direction) which is a second direction perpendicular to the first direction.

[0084] On the second substrate 102, for example, as shown in the example of Fig. 6(B), a readout circuit 20, a signal processing unit 112, a control unit 113, etc. are provided for each pixel P. As shown in Fig. 6(A) and (B), the readout circuit 20 is provided for the region of one pixel P. The signal processing unit 112 and the control unit 113, etc. are arranged, for example, in peripheral regions of a plurality of readout circuits 20 arranged in a matrix.

[0085] 7(A) and (B), the readout circuit 20 may be provided for a region of multiple pixels P that share the readout circuit 20. In the example shown in Figures 7(A) and (B), the readout circuit 20 is disposed for a region of four pixels Pa to Pd, each of which includes a light receiving element 10.

[0086] The above-mentioned resistive element R may be provided, for example, on a substrate (semiconductor substrate) on which each transistor of the readout circuit 20 is provided. As an example, the resistive element R may be a substrate resistor formed by doping an impurity into a semiconductor substrate. The resistive element R may also be provided in a wiring layer on the semiconductor substrate (semiconductor layer).

[0087] Fig. 8 is a diagram for explaining a configuration example of a photodetector according to an embodiment. As an example, the resistive element R may be provided in a wiring layer between a plurality of substrates (semiconductor layers). In the example shown in Fig. 8, the resistive element R is formed in a wiring layer 121 provided between a first substrate 101 and a second substrate 102. The resistive element R may be made of, for example, a metal material such as tungsten (W) or titanium (Ti), polysilicon (Poly-Si), or the like.

[0088] The resistive element R may be provided in the wiring layer 121 or 122 as in the example shown in FIG. 8. The resistive element R may be provided in the second substrate 102. The resistive element R may be composed of a poly resistor or a transistor. The resistive element R may be provided in the first substrate 101.

[0089] 9 to 11 are diagrams showing other configuration examples of the photodetector according to the embodiment. The light receiving element 10 and readout circuit 20 of each pixel P, the signal processing unit 112, the control unit 113, etc. may be provided on one semiconductor substrate (first substrate 101 in FIG. 9) as in the example shown in FIG. 9. Also, as in the example shown in FIG. 9, a conversion unit 70, which is a TDC circuit, may be arranged for each pixel P.

[0090] The photodetector 1 may have a first substrate 101, a second substrate 102, and a third substrate 103, as in the example shown in FIG. 10 or FIG. 11. For example, a signal processing unit 112, a control unit 113, and the like may be arranged on the third substrate 103, as in the example shown in FIG. 10(C) or FIG. 11(C). Note that, as shown in FIG. 11(C), a conversion unit 70 may be provided for each pixel P. In the example shown in FIG. 11, the signal processing unit 112 and the control unit 113 are arranged in the peripheral region of a plurality of conversion units 70 arranged two-dimensionally.

[0091] [Actions and Effects] The photodetection device (photodetection device 1) of this embodiment includes a photodetector (photodetector 10) capable of receiving light and outputting a current, and a first output circuit (first output circuit 40) having a P-type transistor (transistor M2), an N-type transistor (transistor M1), and a resistor (resistance element R) electrically connected in series between a first power supply line (e.g., power supply line L1a) and a reference potential line (reference potential line L2b), and capable of outputting a first signal (signal S11) based on the current of the photodetector.

[0092] In the photodetector 1 according to this embodiment, the first output circuit 40 has a resistive element R electrically connected in series to the transistors M1 and M2. This makes it possible to reduce the dead time. It is possible to realize a photodetector with good detection performance.

[0093] Next, a modified example of the present disclosure will be described. In the following, the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0094] <2. Modifications> (2-1. Variation 1) 12A and 12B are diagrams for explaining a configuration example of a photodetector according to Modification 1 of the present disclosure. The resistive element R may be configured using a transistor M5 as in the example shown in FIG. 12A or 12B. By configuring the resistive element R using a transistor, it is possible to implement the resistive element R in a relatively small area. In the example shown in FIG. 12A, the transistor M5 has a gate to which a predetermined voltage (potential) is applied, and can form a resistive element (resistor).

[0095] 12B, the resistor element R is configured by a diode-connected transistor M5. By providing the diode-connected transistor M5, the voltage amplitude of the signal S11 can be suppressed, and the dead time can be reduced. In the case of this modification, the same effects as those of the above-mentioned embodiment can be obtained.

[0096] (2-2. Variation 2) In the above-described embodiment, a configuration example of the pixel P and the readout circuit 20 has been described, but this is merely an example, and the configurations of the pixel P and the readout circuit 20 are not limited to the above-described example. Fig. 13 is a diagram for explaining a configuration example of a photodetector according to Modification 2. For example, as in the example shown in Fig. 13, the resistive element R of the first output circuit 40 may be electrically connected in series between the power supply line L1a and the transistor M2.

[0097] Fig. 14A is a diagram for explaining another example of the configuration of the photodetector according to Modification 2. In the example shown in Fig. 14A, the cathode of the light receiving element 10 is electrically connected to the power supply line L1b. The anode of the light receiving element 10 is electrically connected to the supply unit 30 and the first output circuit 40. For example, a voltage VSP is applied to the cathode of the light receiving element 10 via the power supply line L1b from a power supply unit (power supply circuit) capable of supplying a voltage. The voltage VSP is, for example, a positive voltage.

[0098] In the example shown in Fig. 14A, the resistive element R is electrically connected between the transistor M1 and the node N2. Note that, as in the example shown in Fig. 14B, the resistive element R may be electrically connected between the transistor M1 and the reference potential line L2b. In the case of the photodetector 1 according to this modification, the provision of the resistive element R can also prevent the dead time from increasing. It is possible to suppress deterioration of the accuracy of photodetection.

[0099] (2-3. Variation 3) 15 and 16 are diagrams for explaining a configuration example of a photodetector according to Modification 3. As in the example shown in FIG. 15 or 16, the first output circuit 40 may have a multi-stage circuit (e.g., an inverter). The first output circuit 40 may output a signal S11 amplified by the multi-stage circuit. For example, as in the example shown in FIG. 15, the resistive element R may be electrically connected in series between the transistor M1c and the transistor M2c in the third stage of the multiple stages.

[0100] 16, the resistor element R may be electrically connected in series between the first-stage transistor M1a and the transistor M2a. This modification can also provide the same effects as those of the above-described embodiment. Each of the first output circuit 40 and the second output circuit 50 may have multiple stages of circuits.

[0101] (2-4. Variation 4) In the above-mentioned embodiment and modified examples, configuration examples of the first output circuit 40 have been described, but the configuration of the first output circuit 40 is not limited to the above-mentioned examples. Figures 17 and 18 are diagrams for explaining a configuration example of a photodetector according to modified example 4. The first output circuit 40 may have a configuration of a NAND circuit, as in the example shown in Figure 17 or Figure 18.

[0102] The pixel control unit 111 (see FIG. 1) is configured to supply, for example, a signal EN serving as an enable signal to the first output circuit 40, and control the output of a signal from the first output circuit 40. For example, when the signal EN serving as a control signal is at a high level, the first output circuit 40 is capable of generating a signal S11 and outputting it to the second output circuit 50. The first output circuit 40 may have a configuration of a NOR circuit. The second output circuit 50 may have a configuration of a NAND circuit, a NOR circuit, or the like.

[0103] (2-5. Variation 5) FIG. 19 is a diagram for explaining a configuration example of a photodetector according to Modification 5. The first output circuit 40 and the second output circuit 50 may be electrically connected to different reference potential lines. In the example shown in FIG. 19, the first output circuit 40 is electrically connected to the reference potential line L2b. Moreover, the second output circuit 50 is electrically connected to the reference potential line L3b. In this case, it is possible to suppress the noise component of the IR drop caused by the shoot-through current from propagating between the first output circuit 40 and the second output circuit 50.

[0104] <3. Usage example> The above-described light detection device 1 and light detection system 200 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. ·Digital cameras, mobile devices with camera functions, and other devices that take images for viewing purposes - Devices used for traffic purposes, such as on-board sensors that take pictures of the front, rear, surroundings, and interior of a vehicle for safe driving (such as automatic stopping) and for recognition of the driver's condition, surveillance cameras that monitor moving vehicles and roads, and distance measuring sensors that measure distances between vehicles, etc. - A device used in home appliances such as televisions, refrigerators, and air conditioners to capture user gestures and operate the appliances according to those gestures. -Medical and healthcare equipment, such as endoscopes and devices that take blood vessel images using infrared light - Equipment used for security purposes, such as surveillance cameras for crime prevention and cameras for person authentication - Cosmetic devices such as skin measuring devices that take pictures of the skin and microscopes that take pictures of the scalp - Devices used for sports, such as action cameras and wearable cameras for sports use Agricultural equipment such as cameras for monitoring fields and crop conditions

[0105] <4. Application Examples> (Example of application to moving objects) 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 moving body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, etc.

[0106] FIG. 20 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a moving object control system to which the technology according to the present disclosure can be applied.

[0107] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 20, 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, as functional configurations of the integrated control unit 12050, a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053 are illustrated.

[0108] 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.

[0109] The body system control unit 12020 controls the operation of various devices mounted on 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 head lamps, back lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals of various switches transmitted from a portable device that replaces a key may be input to the body system control unit 12020. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, and the like of the vehicle.

[0110] 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 an image outside the vehicle and receives the captured image. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for a person, a car, an obstacle, a sign, or characters on a road surface, based on the received image.

[0111] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according 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.

[0112] 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.

[0113] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the outside-of-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output a control command 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 avoiding or mitigating a vehicle collision, following a vehicle based on the distance between vehicles, maintaining vehicle speed, warning a vehicle collision, or warning a vehicle from leaving a lane.

[0114] 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 the driver's operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0115] 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-vehicle 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-vehicle information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

[0116] The audio / image output unit 12052 transmits at least one output signal of audio and image to an output device capable of visually or audibly notifying information to passengers in the vehicle or the outside of the vehicle. In the example of Fig. 20, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as the output device. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

[0117] FIG. 21 is a diagram showing an example of the installation position of the imaging unit 12031.

[0118] In FIG. 21, a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as an imaging unit 12031.

[0119] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the upper part of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The images of the front acquired by the imaging units 12101 and 12105 are mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

[0120] 21 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, an overhead image of the vehicle 12100 viewed from above is obtained by superimposing the image data captured by the imaging units 12101 to 12104.

[0121] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera made up of a plurality of imaging elements, or may be an imaging element having pixels for detecting a phase difference.

[0122] For example, the microcomputer 12051 can extract, as a preceding vehicle, a three-dimensional object that is the closest three-dimensional object on the travel path of the vehicle 12100 and travels at a predetermined speed (for example, 0 km / h or more) in approximately the same direction as the vehicle 12100, by calculating the distance to each three-dimensional object in the imaging ranges 12111 to 12114 and the change over time of this distance (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. Furthermore, the microcomputer 12051 can set a vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including follow-up stop control) and automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of automatic driving that travels autonomously without relying on the driver's operation.

[0123] For example, the microcomputer 12051 classifies and extracts three-dimensional object data on 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. Then, the microcomputer 12051 determines a collision risk indicating 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.

[0124] At least one of the imaging 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 or not a pedestrian is present in the captured images of the imaging units 12101 to 12104. The recognition of such a pedestrian is performed, for example, by a procedure of extracting feature points in the captured images of the imaging units 12101 to 12104 as infrared cameras, and a procedure of performing pattern matching processing on a series of feature points that indicate the contour of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

[0125] 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 imaging unit 12031 among the configurations described above. Specifically, for example, the light detection device 1 can be applied to the imaging unit 12031. By applying the technology according to the present disclosure to the imaging unit 12031, a high-definition captured image can be obtained, and high-precision control using the captured image can be performed in the mobile object control system.

[0126] Although the present disclosure has been described above by giving embodiments, modifications, examples of use, and application examples, the present technology is not limited to the above-described embodiments, etc., and various modifications are possible. For example, although the above-described modifications have been described as modifications of the above-described embodiments, the configurations of the modifications can be appropriately combined.

[0127] A photodetector according to an embodiment of the present disclosure includes a light receiving element capable of receiving light and outputting a current, and a first output circuit having a P-type transistor, an N-type transistor, and a resistor electrically connected in series between a first power supply line and a reference potential line, and capable of outputting a first signal based on the current of the light receiving element, thereby making it possible to realize a photodetector having good detection performance.

[0128] In addition, the effects described in this specification are merely examples and are not limited to the description, and other effects may be obtained. In addition, the present disclosure may have the following configurations. (1) a light receiving element capable of receiving light and outputting a current; a first output circuit including a P-type transistor, an N-type transistor, and a resistor element electrically connected in series between a first power supply line and a reference potential line, and capable of outputting a first signal based on a current of the light receiving element; A light detection device comprising: (2) The resistive element is electrically connected in series between the P-type transistor and the N-type transistor. The light detection device according to (1) above. (3) The resistive element is electrically connected between the P-type transistor and a first node to which the first signal is output. The optical detection device according to (1) or (2). (4) a second output circuit capable of outputting a second signal based on the first signal; the light receiving element has a cathode electrically connected to the first output circuit; the resistive element is electrically connected between the P-type transistor and a first node to which the first signal is output, and is electrically connected to the N-type transistor via the first node; The second output circuit is electrically connected to the first node. The optical detection device according to any one of (1) to (3). (5) the light receiving element has a cathode electrically connected to the first output circuit; The resistive element is electrically connected between the first power supply line and the P-type transistor. The optical detection device according to any one of (1) to (3). (6) a second output circuit capable of outputting a second signal based on the first signal; the light receiving element has an anode electrically connected to the first output circuit; the resistive element is electrically connected between the N-type transistor and a first node to which the first signal is output, and is electrically connected to the P-type transistor via the first node; The second output circuit is electrically connected to the first node. The optical detection device according to (1) or (2). (7) the light receiving element has an anode electrically connected to the first output circuit; The resistive element is electrically connected between the N-type transistor and the reference potential line. The optical detection device according to (1) or (2). (8) The P-type transistor and the N-type transistor each have a gate electrically connected to the light receiving element. The optical detection device according to any one of (1) to (7). (9) The light receiving element further includes a supply circuit capable of supplying a current thereto. The photodetector according to any one of (1) to (8). (10) The first output circuit has an inverter including the P-type transistor and the N-type transistor. The photodetector according to any one of (1) to (9) above. (11) a second output circuit electrically connected to the first output circuit and capable of outputting a second signal based on the first signal; The second output circuit is electrically connected to a second power supply line different from the first power supply line. The optical detection device according to any one of (1) to (10) above. (12) a first substrate having a plurality of the light receiving elements; a second substrate having a plurality of the first output circuits and stacked on the first substrate; Further equipped The photodetector according to any one of (1) to (11) above. (13) a second output circuit electrically connected to the first output circuit and capable of outputting a second signal based on the first signal; The second substrate has a plurality of the second output circuits. The light detection device according to (12) above. (14) The first output circuit and the second output circuit are provided for each of the light receiving elements or for each of a plurality of the light receiving elements. The optical detection device according to (13) above. (15) Further provided is a third substrate having a signal processing section capable of performing signal processing. The photodetector according to any one of (12) to (14) above. (16) a second output circuit electrically connected to the first output circuit and capable of outputting a second signal based on the first signal; the third substrate has a plurality of the second output circuits; The signal processing unit is capable of performing signal processing of the second signal. The optical detection device according to (15) above. (17) The resistance element is formed using a transistor. The photodetector according to any one of (1) to (16) above. (18) The reference potential line is a ground line. The photodetector according to any one of (1) to (17) above. (19) The light receiving element is an avalanche photodiode. The photodetector according to any one of (1) to (18) above. (20) A light source capable of irradiating light onto an object; a light detection device that receives light from the object; Equipped with The light detection device includes: a light receiving element capable of receiving light and outputting a current; a first output circuit including a P-type transistor, an N-type transistor, and a resistor element electrically connected in series between a first power supply line and a reference potential line, and capable of outputting a first signal based on a current of the light receiving element; have Optical detection system. [Explanation of symbols]

[0129] 1...photodetection device, 10...photoreceiving element, 20...readout circuit, 30...supply section, 40...first output circuit, 50...second output circuit, 100...pixel section, 101...first substrate, 102...second substrate, 103...third substrate, 112...signal processing section, 200...photodetection system, 210...light source control section, 220...light source.

Claims

1. a light receiving element capable of receiving light and outputting a current; a first output circuit including a P-type transistor, an N-type transistor, and a resistor element electrically connected in series between a first power supply line and a reference potential line, and capable of outputting a first signal based on a current of the light receiving element; A light detection device comprising:

2. The resistive element is electrically connected in series between the P-type transistor and the N-type transistor.

2. The optical detection device according to claim 1.

3. The resistive element is electrically connected between the P-type transistor and a first node to which the first signal is output.

2. The optical detection device according to claim 1.

4. a second output circuit capable of outputting a second signal based on the first signal; the light receiving element has a cathode electrically connected to the first output circuit; the resistive element is electrically connected between the P-type transistor and a first node to which the first signal is output, and is electrically connected to the N-type transistor via the first node; The second output circuit is electrically connected to the first node.

2. The optical detection device according to claim 1.

5. the light receiving element has a cathode electrically connected to the first output circuit; The resistive element is electrically connected between the first power supply line and the P-type transistor.

2. The optical detection device according to claim 1.

6. a second output circuit capable of outputting a second signal based on the first signal; the light receiving element has an anode electrically connected to the first output circuit; the resistive element is electrically connected between the N-type transistor and a first node to which the first signal is output, and is electrically connected to the P-type transistor via the first node; The second output circuit is electrically connected to the first node.

2. The optical detection device according to claim 1.

7. the light receiving element has an anode electrically connected to the first output circuit; The resistive element is electrically connected between the N-type transistor and the reference potential line.

2. The optical detection device according to claim 1.

8. The P-type transistor and the N-type transistor each have a gate electrically connected to the light receiving element.

2. The optical detection device according to claim 1.

9. The light receiving element further includes a supply circuit capable of supplying a current thereto.

2. The optical detection device according to claim 1.

10. The first output circuit has an inverter including the P-type transistor and the N-type transistor.

2. The optical detection device according to claim 1.

11. a second output circuit electrically connected to the first output circuit and capable of outputting a second signal based on the first signal; The second output circuit is electrically connected to a second power supply line different from the first power supply line.

2. The optical detection device according to claim 1.

12. a first substrate having a plurality of the light receiving elements; a second substrate having a plurality of the first output circuits and stacked on the first substrate; Further equipped 2. The optical detection device according to claim 1.

13. a second output circuit electrically connected to the first output circuit and capable of outputting a second signal based on the first signal; The second substrate has a plurality of the second output circuits.

13. The optical detection device of claim 12.

14. The first output circuit and the second output circuit are provided for each of the light receiving elements or for each of a plurality of the light receiving elements.

14. The optical detection device of claim 13.

15. Further provided is a third substrate having a signal processing section capable of performing signal processing.

13. The optical detection device of claim 12.

16. a second output circuit electrically connected to the first output circuit and capable of outputting a second signal based on the first signal; the third substrate includes a plurality of the second output circuits, The signal processing unit is capable of performing signal processing of the second signal.

16. The optical detection device of claim 15.

17. The resistance element is formed using a transistor.

2. The optical detection device according to claim 1.

18. The reference potential line is a ground line.

2. The optical detection device according to claim 1.

19. The light receiving element is an avalanche photodiode.

2. The optical detection device according to claim 1.

20. A light source capable of irradiating light onto an object; a light detection device that receives light from the object; Equipped with The light detection device includes: a light receiving element capable of receiving light and outputting a current; a first output circuit including a P-type transistor, an N-type transistor, and a resistor element electrically connected in series between a first power supply line and a reference potential line, and capable of outputting a first signal based on a current of the light receiving element; have Optical detection system.

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