Imaging apparatus, electronic apparatus, and imaging method

Abstract

[PROBLEM] To improve sensitivity, reduce dark current, and reduce power consumption. [SOLUTION] An imaging device includes: a photoelectric conversion unit including a plurality of photoelectric conversion elements each photoelectrically converting incident light to generate an electric signal; a detector configured to output a detection signal indicating whether a change amount of the electric signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value; a pixel signal generation unit configured to generate a pixel signal based on the electric signal; a transfer controller configured to perform control to transfer the electric signal to the pixel signal generation unit; and an analog-to-digital converter configured to convert the pixel signal into a digital signal. A low-potential side reference potential of the photoelectric conversion unit, a low-potential side reference potential of the detector, a low-potential side reference potential of the pixel signal generation unit, a low-potential side reference potential of the analog-to-digital converter, and an off potential of the transfer controller include three or more potentials having different potential levels.

Description

Technical Field

[0001] The present disclosure relates to an imaging device, an electronic device, and an imaging method. Background Art

[0002] In conventional imaging devices, a synchronous imaging element that captures image data (frames) in synchronization with a synchronization signal such as a vertical synchronization signal is generally used. This synchronous imaging element can only acquire image data within one cycle of the synchronization signal (e.g., 1 / 60 second), and is therefore not suitable for acquiring image data at high speed. Therefore, an asynchronous imaging element has been proposed, in which an event detection circuit is provided for each pixel, and the event detection circuit detects in real time for each pixel address that the amount of light of the pixel exceeds a threshold as an event (e.g., see Patent Document 1). In these imaging elements, a photodiode and a plurality of transistors for detecting events are provided for each pixel.

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: Japanese Translation of PCT International Publication No. 2016-533140 Summary of the Invention

[0006] Problems to be solved by the present invention

[0007] In the above-mentioned asynchronous imaging element, data can be generated and output at high speed compared to the synchronous imaging element. For this reason, for example, in the field of traffic, safety can be improved by performing processing of images for identifying people or obstacles at high speed. However, when the reverse bias voltage of the photodiode decreases due to voltage fluctuations such as a decrease in the power supply voltage or an increase in the ground voltage, the sensitivity of the photodiode may decrease and the dark current may increase. Therefore, there is a problem of signal quality degradation due to insufficient sensitivity and dark current. Increasing the area of ​​the photodiode can improve sensitivity and reduce dark current, but this is undesirable because it reduces the number of pixels per unit area. In addition, by sufficiently increasing the power supply voltage, sensitivity can be improved and dark current can be reduced, but power consumption is thereby increased, which is not preferred.

[0008] The present disclosure provides an imaging device, an electronic device, and an imaging method capable of improving sensitivity, reducing dark current, and reducing power consumption.

[0009] Solution to the problem

[0010] In order to solve the above-mentioned problems, according to the present disclosure, an imaging device is provided, including: a photoelectric conversion unit including a plurality of photoelectric conversion elements, each photoelectric conversion element photoelectrically converting incident light to generate an electrical signal; a detector configured to output a detection signal indicating whether the amount of change in the electrical signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value, a pixel signal generating unit configured to generate a pixel signal based on the electrical signal, a transmission controller configured to perform control of transmitting the electrical signal to the pixel signal generating unit, and an analog-to-digital converter configured to convert the pixel signal into a digital signal, wherein the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the off potential of the transmission controller include three or more potentials with different potential levels.

[0011] The potential level of the low potential side reference potential of the photoelectric conversion unit may be lower than the potential level of the low potential side reference potential of the detector.

[0012] The potential level of the low potential side reference potential of the photoelectric conversion unit may be higher than the potential level of the off potential of the transmission controller.

[0013] A potential level of the low potential side reference potential of the photoelectric conversion unit may be lower than a potential level of the low potential side reference potential of at least one of the pixel signal generation unit and the analog-to-digital converter.

[0014] At least one of the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter and the shutdown potential of the transmission controller can be a ground potential, at least one of the others can be a first reference potential having a potential level lower than the ground potential, and at least one of the others can be a second reference potential having a potential level lower than the first reference potential.

[0015] The low potential side reference potential of the photoelectric conversion unit can be the second reference potential, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit and the low potential side reference potential of the analog-to-digital converter can be the ground potential, and the shutdown potential of the transmission controller can be the second reference potential.

[0016] The ground potential may be 0 V, the first reference potential may be a negative potential, and the second reference potential may be a negative potential having a potential level lower than that of the first reference potential.

[0017] The low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the pixel signal generation unit, and the low potential side reference potential of the analog-to-digital converter may be substantially equal.

[0018] At least one of the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter and the shutdown potential of the transmission controller can be a ground potential, at least one of the others can be a first reference potential having a potential level lower than the ground potential, and at least one of the other potentials can be a second reference potential having a potential level higher than the ground potential.

[0019] The low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the pixel signal generating unit and the low potential side reference potential of the analog-to-digital converter can be the ground potential, the low potential side reference potential of the detector can be the first reference potential, and the shutdown potential of the transmission controller can be the second reference potential.

[0020] The ground potential may be 0 V, the first reference potential may be a positive potential, and the second reference potential may be a negative potential.

[0021] According to the present disclosure, there is provided an imaging device, comprising: a photoelectric conversion unit including a plurality of photoelectric conversion elements, each of which photoelectrically converts incident light to generate an electrical signal; a detector configured to output a detection signal indicating whether an amount of change in the electrical signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value; a pixel signal generating unit configured to generate a pixel signal based on the electrical signal, a transmission controller configured to perform control of transmitting the electrical signal to the pixel signal generating unit; an analog-to-digital converter configured to convert the pixel signal into a digital signal, and a potential selecting unit configured to switch a low-potential-side reference potential of the photoelectric conversion unit.

[0022] When the detector detects that the change amount exceeds a predetermined threshold, the analog-to-digital converter may convert the pixel signal into a digital signal, and the potential selection unit may select a first reference potential within a time period when the detector detects whether the change amount exceeds the predetermined threshold, and select a second reference potential having a higher potential level than the first reference potential within a time period when the analog-to-digital converter converts the pixel signal into a digital signal.

[0023] The first reference potential may be a negative potential, and the second reference potential may be a ground potential.

[0024] The low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shutdown potential of the transmission controller may include two or more potentials with different potential levels.

[0025] The low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, and the low potential side reference potential of the analog-to-digital converter may be a ground potential, and the off potential of the transmission controller may be a negative potential.

[0026] A potential generating unit configured to generate at least one of a first reference potential and a second reference potential may be included.

[0027] At least the detector may be provided on the second substrate stacked on the first substrate, and the photoelectric conversion unit is provided on the first substrate.

[0028] The back gate of the transistor in the transmission controller may be set to a potential at the same potential level as the low potential side reference potential of the photoelectric conversion unit.

[0029] According to another aspect of the present disclosure, there is provided an electronic device including: an imaging device configured to output captured image data; and

[0030] a processor configured to perform predetermined signal processing on the image data, wherein the imaging device comprises:

[0031] a photoelectric conversion unit including a plurality of photoelectric conversion elements, each of the plurality of photoelectric conversion elements performing photoelectric conversion on incident light to generate an electrical signal;

[0032] A detector configured to output a detection signal indicating whether the amount of change in the electrical signal of each of a plurality of photoelectric conversion elements exceeds a predetermined threshold value, a pixel signal generating unit configured to generate a pixel signal based on the electrical signal, a transmission controller configured to perform control of transmitting the electrical signal to the pixel signal generating unit, and an analog-to-digital converter configured to convert the pixel signal into a digital signal, wherein the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shut-off potential of the transmission controller include three or more potentials with different potential levels.

[0033] According to another aspect of the present disclosure, there is provided an imaging method, comprising: a step of photoelectrically converting incident light using a plurality of photoelectric conversion elements to generate an electrical signal; a step of outputting a detection signal indicating whether an amount of change in the electrical signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value; a step of transmitting the electrical signal; a step of generating a pixel signal based on the transmitted electrical signal; and a step of converting the pixel signal into a digital signal, wherein a low potential side reference potential at the time of photoelectric conversion, a low potential side reference potential at the time of outputting the detection signal, a low potential side reference potential at the time of generating the pixel signal, a low potential side reference potential at the time of converting the pixel signal into the digital signal, and an off potential at the time of transmitting the electrical signal include three or more potentials having different potential levels; and

[0034] Using these potentials, the steps of generating an electric signal, outputting a detection signal, transmitting the electric signal, generating a pixel signal, and converting the detection signal into a digital signal are performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a block diagram showing a configuration example of an imaging device according to the first embodiment.

[0036] Figure 2 is a diagram illustrating an example of a laminated structure of the solid-state image sensing device according to the first embodiment.

[0037] Figure 3 is a block diagram showing a configuration example of the solid-state image sensing device in the first embodiment.

[0038] Figure 4 is a block diagram showing a configuration example of a pixel array unit according to the first embodiment.

[0039] Figure 5 is a circuit diagram showing a configuration example of a pixel block according to the first embodiment.

[0040] Figure 6 is a block diagram showing a first configuration example of the address event detector.

[0041] Figure 7 is a circuit diagram showing a configuration example of a current-voltage converter according to the first embodiment.

[0042] Figure 8 is a circuit diagram showing a configuration example of a subtractor and a quantizer according to the first embodiment.

[0043] Figure 9 is a block diagram showing a configuration example of a column ADC according to the first embodiment.

[0044] Figure 10is a timing chart showing an example of the operation of the solid-state image sensing device according to the first embodiment.

[0045] Figure 11 is a flowchart illustrating an example of the operation of the solid-state image sensing device according to the first embodiment.

[0046] Figure 12 : is a diagram illustrating a low potential side reference potential and an off potential used by each unit in the imaging device according to the first embodiment.

[0047] Figure 13A is a diagram showing an example of a potential level in a case where a transfer transistor in the first embodiment is turned off.

[0048] Figure 13B is a diagram showing an example of a potential level in a case where the transfer transistor of the first embodiment is turned on.

[0049] Figure 14 is a diagram illustrating a low potential side reference potential and an off potential used by each unit in the imaging device according to the second embodiment.

[0050] Figure 15A 1 is a diagram showing an example of a potential level in a case where the transfer transistor of the second embodiment is turned off.

[0051] Figure 15B : is a diagram showing an example of the potential level in the case where the transfer transistor of the second embodiment is turned on.

[0052] Figure 16 is a diagram illustrating a low potential side reference potential and an off potential used by each unit in the imaging device according to the third embodiment.

[0053] Figure 17 is a block diagram showing a second configuration example of the address event detector.

[0054] Figure 18 is a block diagram showing a configuration example of a scanning type image forming apparatus.

[0055] Figure 19 : is a block diagram showing a schematic configuration example of a vehicle control system as an example of a mobile body control system.

[0056] Figure 20 is a diagram showing an example of the installation positions of the imaging unit and the vehicle exterior information detector. DETAILED DESCRIPTION

[0057] Hereinafter, embodiments of an imaging device, an electronic device, and an imaging method will be described with reference to the accompanying drawings. While the following primarily describes the primary configuration components of the imaging device and the electronic device, the imaging device and the electronic device may have components and functions not shown or described. The following description does not exclude configuration components and functions not shown or described.

[0058] <1. First embodiment>

[0059] [Configuration Example of Imaging Device]

[0060] Figure 1 1 is a block diagram illustrating a configuration example of an imaging device 100 according to a first embodiment of the present disclosure. The imaging device 100 includes an imaging lens 110, a solid-state image sensing device 200, a recording unit 120, and a controller 130. As the imaging device 100, a camera mounted on an industrial robot, a vehicle-mounted camera, or the like is assumed.

[0061] The imaging lens 110 condenses incident light and guides the light to the solid-state image sensing device 200. The solid-state image sensing device 200 photoelectrically converts the incident light to capture image data. The solid-state image sensing device 200 performs predetermined signal processing (such as image recognition processing) on ​​the captured image data and outputs a detection signal indicating the data and address event of the processing result to the recording unit 120 via the signal line 209. The method of generating the detection signal will be described later.

[0062] The recording unit 120 records data from the solid-state image sensing device 200. The controller 130 controls the solid-state image sensing device 200 to capture image data.

[0063] [Configuration Example of Solid-State Image Sensing Device]

[0064] Figure 2 This diagram illustrates an example of a laminated structure of a solid-state image sensing device 200 according to the first embodiment of the present disclosure. The solid-state image sensing device 200 includes a detection chip 202 and a light receiving chip 201 stacked on the detection chip 202. These chips are electrically connected via a connection such as a via. Note that in addition to vias, connections can also be made using Cu-Cu bonding or bumps.

[0065] Figure 3 1 is a block diagram showing a configuration example of the solid-state image sensing device 200 in the first embodiment of the present invention. The solid-state image sensing device 200 includes a drive circuit 211 , a signal processing unit 212 , an arbiter 213 , a column ADC 220 , and a pixel array unit 300 .

[0066] In the pixel array unit 300, a plurality of pixels are arranged in a two-dimensional grid pattern. Furthermore, the pixel array unit 300 is divided into a plurality of pixel blocks, each of which includes a predetermined number of pixels. Hereinafter, a group of pixels or pixel blocks arranged in a horizontal direction is referred to as a "row," and a group of pixels or pixel blocks arranged in a direction perpendicular to a row is referred to as a "column."

[0067] Each pixel generates an analog signal corresponding to the voltage of the photocurrent as a pixel signal. Furthermore, each pixel block detects the presence or absence of an address event based on whether the change in photocurrent exceeds a predetermined threshold. When an address event occurs, the pixel block outputs a request to arbiter 213.

[0068] The driving circuit 211 drives each pixel to output a pixel signal to the column ADC 220 .

[0069] The arbiter 213 arbitrates requests from each pixel block and sends a response to the pixel block based on the arbitration result. The pixel block that receives the response provides a detection signal indicating the detection result to the drive circuit 211 and the signal processing unit 212.

[0070] For each column of the pixel block, the column ADC 220 converts the analog pixel signal from the column into a digital signal. The column ADC 220 provides the digital signal to the signal processing unit 212.

[0071] The signal processing unit 212 performs predetermined signal processing such as correlated double sampling (CDS) processing or image recognition processing on the digital signal from the column ADC 220 . The signal processing unit 212 supplies data indicating the processing result and a detection signal to the recording unit 120 via the signal line 209 .

[0072] [Configuration Example of Pixel Array Unit]

[0073] Figure 4 1 is a block diagram showing a configuration example of a pixel array unit 300 according to a first embodiment of the present disclosure. The pixel array unit 300 is divided into a plurality of pixel blocks 310. In each pixel block 310, a plurality of pixels are arranged in I rows×J columns (I and J are integers).

[0074] Furthermore, the pixel block 310 includes a pixel signal generating unit 320, a plurality of light receiving units 330 in I rows and J columns, and an address event detector 400. The plurality of light receiving units 330 in the pixel block 310 share the pixel signal generating unit 320 and the address event detector 400. The circuit comprising the light receiving unit 330, the pixel signal generating unit 320, and the address event detector 400 at a specific coordinate then functions as a pixel at that coordinate. Furthermore, a vertical signal line VSL is wired for each column of the pixel block 310. When the number of columns in the pixel block 310 is m (m is an integer), m vertical signal lines VSL are arranged.

[0075] The light receiving unit 330 performs photoelectric conversion on incident light to generate a photocurrent. Under the control of the driving circuit 211 , the light receiving unit 330 provides the photocurrent to the pixel signal generating unit 320 or the address event detector 400 .

[0076] The pixel signal generating unit 320 generates a signal of a voltage corresponding to the photocurrent as the pixel signal SIG. The pixel signal generating unit 320 provides the generated pixel signal SIG to the column ADC 220 via the vertical signal line VSL.

[0077] The address event detector 400 detects the presence or absence of an address event based on whether the amount of change in the photocurrent from each light receiving unit 330 exceeds a predetermined threshold. Address events include, for example, a turn-on event indicating that the amount of change has exceeded an upper threshold, and a turn-off event indicating that the amount of change has fallen below a lower threshold. Furthermore, the detection signal for the address event includes, for example, one bit indicating the detection result of a turn-on event and one bit indicating the detection result of a turn-off event. Note that the address event detector 400 may also detect only a turn-on event.

[0078] When an address event occurs, the address event detector 400 provides a request for requesting transmission of a detection signal to the arbitrator 213. Then, when a response to the request is received from the arbitrator 213, the address event detector 400 provides a detection signal to the driver circuit 211 and the signal processing unit 212. Note that the address event detector 400 is an example of the detector described in the claims.

[0079] [Pixel block configuration example]

[0080] Figure 5 1 is a circuit diagram showing an example configuration of a pixel block 310 according to the first embodiment of the present disclosure. In the pixel block 310, the pixel signal generating unit 320 includes a reset transistor 321, an amplifying transistor 322, a selecting transistor 323, and a floating diffusion layer 324. The plurality of light receiving cells 330 in the pixel block 310 are commonly connected to the address event detector 400 via a connection node 340.

[0081] In addition, each light receiving unit in the light receiving unit 330 includes a transfer transistor 331, an overcurrent gate (OFG) transistor 332, and a photoelectric conversion element 333. Assuming that the number of pixels in the pixel block 310 is N (N is an integer), N transfer transistors 331, N OFG transistors 332, and N photoelectric conversion elements 333 are arranged. A transfer signal TRGn is provided by the drive circuit 211 to the gate of the nth (n is an integer from 1 to N) transfer transistor 331 in the pixel block 310. A control signal OFGn is provided to the gate of the nth OFG transistor 332 through the drive circuit 211. In this specification, the transfer transistor 331 and the OFG transistor 332 are collectively referred to as a transfer transistor 335, and the photoelectric conversion element is referred to as a photoelectric conversion unit 334.

[0082] Furthermore, for example, N-type metal oxide semiconductor (MOS) transistors are used as the reset transistor 321, the amplifying transistor 322, and the selecting transistor 323. Similarly, N-type MOS transistors are used for the transfer transistor 331 and the OFG transistor 332.

[0083] In addition, each of the photoelectric conversion elements 333 is arranged on the light receiving chip 201. All elements other than the photoelectric conversion elements 333 are arranged on the detection chip 202. It should be noted that a modified example in which a part of the elements other than the photoelectric conversion elements 333 are provided on the light receiving chip 201 is also conceivable.

[0084] The photoelectric conversion element 333 photoelectrically converts incident light to generate charge. The transfer transistor 331 transfers the charge from the corresponding photoelectric conversion element 333 to the floating diffusion layer 324 according to the transfer signal TRGn. The OFG transistor 332 provides the electrical signal generated by the corresponding photoelectric conversion element 333 to the connection node 340 according to the control signal OFGn. Here, the provided electrical signal is a photocurrent containing charge.

[0085] The floating diffusion layer 324 accumulates charge and generates a voltage corresponding to the amount of accumulated charge. The reset transistor 321 initializes the charge level of the floating diffusion layer 324 based on a reset signal from the drive circuit 211. The amplifier transistor 322 amplifies the voltage of the floating diffusion layer 324. The select transistor 323 outputs the amplified voltage signal as a pixel signal SIG to the column ADC 220 via the vertical signal line VSL based on a select signal SEL from the drive circuit 211.

[0086] When the controller 130 instructs to start detecting an address event, the driver circuit 211 drives the OFG transistors 332 of all pixels through the control signal OFGn to supply photocurrent to the connection node 340. Therefore, the total photocurrent of all light receiving units 330 in the pixel block 310 is provided to the address event detector 400.

[0087] Then, when an address event is detected in a specific pixel block 310, the driver circuit 211 turns off all the OFG transistors 332 of the block and stops supplying photocurrent to the address event detector 400. Next, the driver circuit 211 sequentially drives each transfer transistor 331 through the transfer signal TRGn to transfer charge to the floating diffusion layer 324. Thus, the pixel signal of each of the multiple pixels in the pixel block 310 is sequentially output.

[0088] In this manner, the solid-state image sensing device 200 outputs only the pixel signals of the pixel block 310 in which the address event has been detected to the column ADC 220. Therefore, compared to the case of outputting the pixel signals of all pixels, regardless of the presence or absence of the address event, the power consumption of the solid-state image sensing device 200 and the amount of image processing can be reduced.

[0089] Furthermore, since the address event detector 400 is shared by a plurality of pixels, the circuit scale of the solid-state image sensing device 200 can be reduced compared to a case where the address event detector 400 is provided for each pixel.

[0090] [Configuration Example of Address Event Detector 400]

[0091] Figure 6 4 is a block diagram showing a first configuration example of the address event detector 400 according to the first embodiment of the present disclosure. The address event detector 400 includes a current-voltage converter 410, a buffer 420, a subtractor 430, a quantizer 440, and a transmission unit 450.

[0092] The current-voltage converter 410 converts the photocurrent from the corresponding light receiving unit 330 into a logarithmic voltage signal. The current-voltage converter 410 supplies the voltage signal to the buffer 420.

[0093] The buffer 420 corrects the voltage signal from the current-voltage converter 410 and outputs the corrected voltage signal to the subtractor 430.

[0094] The subtractor 430 reduces the level of the voltage signal from the buffer 420 according to the row driving signal from the driving circuit 211. The subtractor 430 supplies the reduced voltage signal to the quantizer 440.

[0095] The quantizer 440 quantizes the voltage signal from the subtractor 430 into a digital signal and outputs the digital signal as a detection signal to the transmission unit 450 .

[0096] The transmission unit 450 transmits the detection signal from the quantizer 440 to the signal processing unit 212 and the like. When an address event is detected, the transmission unit 450 provides a request for transmitting the detection signal to the arbitrator 213. Then, when a response to the request is received from the arbitrator 213, the transmission unit 450 provides the detection signal to the driver circuit 211 and the signal processing unit 212.

[0097] [Configuration Example of Current-to-Voltage Converter]

[0098] Figure 7 : is a circuit diagram showing a configuration example of a current-voltage converter 410 according to the first embodiment of the present disclosure. The current-voltage converter 410 includes N-type transistors 411 and 413 and a P-type transistor 412. As these transistors, for example, MOS transistors are used.

[0099] The source of the N-type transistor 411 is connected to the light receiving unit 330, and its drain is connected to the power supply terminal. The P-type transistor 412 and the N-type transistor 413 are connected in series between the power supply terminal and the ground terminal. In addition, the connection node of the P-type transistor 412 and the N-type transistor 413 is connected to the gate of the N-type transistor 411 and the input terminal of the buffer 420. In addition, a predetermined bias voltage Vbias is applied to the gate of the P-type transistor 412.

[0100] The drains of the N-type transistors 411 and 413 are connected to the power supply side, and such a circuit is called a source follower. The photocurrent from the light receiving unit 330 is converted into a logarithmic voltage signal by the two source followers connected in a loop shape. In addition, the P-type transistor 412 provides a constant current to the N-type transistor 413.

[0101] [Configuration example of subtractor and quantizer]

[0102] Figure 8 4 is a circuit diagram showing a configuration example of a subtractor 430 and a quantizer 440 according to the first embodiment of the present invention. The subtractor 430 includes capacitors 431 and 433, an inverter 432, and a switch 434. In addition, the quantizer 440 includes a comparator 441.

[0103] One end of the capacitor 431 is connected to the output end of the buffer 420, and the other end is connected to the input end of the inverter 432. The capacitor 433 is connected in parallel to the inverter 432. The switch 434 opens and closes the path connecting both ends of the capacitor 433 according to the row driving signal.

[0104] The inverter 432 inverts the voltage signal input via the capacitor 431 , and outputs the inverted signal to the non-inverting input terminal (+) of the comparator 441 .

[0105] When switch 434 is turned on, voltage signal Vinit is input to the buffer 420 side of capacitor 431, and the opposite side becomes a virtual ground. For convenience, the potential of the virtual ground is set to zero. At this time, the potential Qinit accumulated in capacitor 431 is expressed by the following equation, where the capacitance of capacitor 431 is C1. On the other hand, since both ends of capacitor 433 are short-circuited, the accumulated charge is zero.

[0106] Qinit=C1×Vinit...(1)

[0107] Next, considering a case where the switch 434 is turned off and the voltage on the buffer 420 side of the capacitor 431 becomes Vafter, the charge Qafter accumulated in the capacitor 431 is expressed by the following equation.

[0108] Qafter=C1×Vafter...(2)

[0109] On the other hand, when the output voltage is Vout, the charge Q2 accumulated in the capacitor 433 is expressed by the following equation.

[0110] Q2=-C2×Vout...(3)

[0111] At this time, since the total amount of charge of the capacitors 431 and 433 does not change, the following equation holds.

[0112] Qinit=Qafter+Q2...(4)

[0113] When equations (1) to (3) are substituted into equation (4) and deformed, the following equation is obtained.

[0114] Vout=-(C1 / C2)×(Vafter-Vinit)...(5)

[0115] Equation (5) represents the subtraction operation of the voltage signal, and the gain of the subtraction result is C1 / C2. Generally, because it is desired to maximize the gain, it is preferred to design the capacitance C1 of the capacitor 431 to be large and the capacitance C2 of the capacitor 433 to be small. On the other hand, when C2 is too small, the kTC noise increases and the noise characteristics may deteriorate. Therefore, the capacity reduction of C2 is limited to the range of tolerable noise. In addition, because the address event detector 400 including the subtractor 430 is installed for each pixel block, the capacitors C1 and C2 have area limitations. Taking these into account, the values ​​of the capacitors C1 and C2 are determined.

[0116] The comparator 441 compares the voltage signal from the subtractor 430 with a predetermined threshold voltage Vth applied to the inverting input terminal (−), and outputs a signal indicating a comparison result to the transmission unit 450 as a detection signal.

[0117] Furthermore, when the conversion gain of the current-voltage converter 410 is CGIog and the gain of the buffer 420 is “1”, the gain A of the entire address event detector 400 is represented by the following equation.

[0118] [Formula 1]

[0119]

[0120] In the above equation, iphoto_n is the photovoltaic current of the n-th pixel, and the unit is, for example, ampere (A). N is the number of pixels in the pixel block 310.

[0121] [Configuration Example of Column ADC 220]

[0122] Figure 9 1 is a block diagram showing a configuration example of the column ADC 220 according to the first embodiment of the present disclosure. The column ADC 220 includes an ADC 230 for each column of pixel blocks 310. In addition, the column ADC 220 includes a reference signal generation unit 223 and an output unit 222. The reference signal generation unit 223 generates a reference signal (such as a ramp signal) and supplies the reference signal to each ADC 230. A digital-to-analog converter (DAC) or the like is used as the reference signal generation unit 223. The output unit 222 supplies the digital signal from the ADC 230 to the signal processing unit 212.

[0123] ADC 230 converts the analog pixel signal SIG supplied via the vertical signal line VSL into a digital signal. ADC 230 includes a comparator 236, a counter 237, a switch 238, and a memory 239. Comparator 236 compares the reference signal with pixel signal SIG, and counter 237 counts the count value over a period of time until the comparison result is inverted. Switch 238 provides and holds the count value in memory 239 under the control of a timing control circuit (not shown) or the like. Memory 239 provides a digital signal indicating the count value to output unit 222 under the control of a horizontal drive unit (not shown) or the like. With this configuration, pixel signal SIG is converted into a digital signal having a greater bit depth than the detection signal. For example, when the detection signal is 2 bits, the pixel signal is converted into a digital signal of 3 bits or more (16 bits, etc.). It should be noted that ADC 230 is an example of an analog-to-digital converter described in the claims.

[0124] [Operation Example of Solid-State Image Sensing Device]

[0125] Figure 10 1 is a timing chart illustrating an example of the operation of the solid-state image sensing device 200 according to the first embodiment of the present disclosure. At timing T0, when the controller 130 issues an instruction to start detecting address events, the driver circuit 211 sets all control signals OFGn to a high level and turns on the OFG transistors 332 of all pixels. Therefore, the sum of the photocurrents of all pixels is provided to the address event detector 400. On the other hand, the transfer signals TRGn are all at a low level, and the transfer transistors 331 of all pixels are in an off state.

[0126] Then, it is assumed that the address event detector 400 detects an address event and outputs a high-level detection signal at timing T1. Here, the detection signal is assumed to be a 1-bit signal indicating a detection result of a power-on event.

[0127] When receiving the detection signal, the driving circuit 211 sets all the control signals OFGn to a low level at timing T2 to stop supplying the photocurrent to the address event detector 400. In addition, the driving circuit 211 sets the selection signal SEL to a high level and sets the reset signal RST to a high level within a certain pulse period to initialize the floating diffusion layer 324. The pixel signal generating unit 320 outputs the voltage at the time of initialization as a reset level, and the ADC 230 converts the reset level into a digital signal.

[0128] At timing T3 after the reset level is converted, the driver circuit 211 provides a high-level transfer signal TRG1 for a certain pulse period, causing the first pixel to output a voltage as a signal level. The ADC 230 converts the signal level into a digital signal. The signal processing unit 212 obtains the difference between the reset level and the signal level as a net pixel signal. This process is called CDS processing.

[0129] At time T4 after the signal level is converted, the driver circuit 211 provides a high-level transfer signal TRG2 for a certain pulse period, causing the second pixel to output the signal level. The signal processing unit 212 obtains the difference between the reset level and the signal level as the net pixel signal. Thereafter, similar processing is performed, and the pixel signals of each pixel in the pixel block 310 are sequentially output.

[0130] When outputting all pixel signals, the drive circuit 211 sets all control signals OFGn to a high level and turns on the OFG transistors 332 of all pixels.

[0131] Figure 11 1 is a flowchart showing an example of the operation of the solid-state image sensing device 200 according to the first embodiment of the present disclosure. For example, when a predetermined application for detecting an address event is executed, the operation is started.

[0132] Each pixel block 310 detects the presence or absence of an address event (step S901). The driver circuit 211 determines whether an address event has occurred in any pixel block 310 (step S902). If an address event has occurred (step S902: Yes), the driver circuit 211 sequentially outputs the pixel signal of each pixel in the pixel block 310 where the address event has occurred (step S903).

[0133] In the case where there is no address event (step S902 : No), or after step S903 , the solid-state image sensing device 200 repeats step S901 and subsequent steps.

[0134] As described above, according to the first embodiment of the present disclosure, since the address event detector 400 detects the amount of change in the photoelectric current of each of the plurality (N) of photoelectric conversion elements 333 (pixels), the number of address event detectors 400 arranged can be one per N pixels. Since N pixels share one address event detector 400 in this manner, the circuit scale can be reduced compared to a configuration in which the address event detector 400 is not shared and is provided for each pixel.

[0135] Note that the above-mentioned value of N is arbitrary. For example, when there is no need to consider reduction in circuit scale, the address event detector 400 may be provided for each pixel where N=1.

[0136] In the first embodiment, the low potential side reference potential and the shutdown potential used by each unit in the imaging device 100 include three or more types of potentials having different potential levels. The low potential side reference potential and the shutdown potential are generally the ground potential GND, but in this embodiment, it is assumed that each unit in the imaging device 100 uses a potential at a potential level other than the ground potential GND.

[0137] More specifically, the low potential side reference potential of the photoelectric conversion unit 334, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit 320, the low potential side reference potential of the column ADC 220, and the shutdown potential of the transmission controller 335 include three or more potentials with different potential levels.

[0138] For example, the potential level of the low potential side reference potential of the photoelectric conversion unit 334 may be lower than the potential level of the low potential side reference potential of the address event detector 400. In addition, the potential level of the low potential side reference potential of the photoelectric conversion unit 334 may be higher than the potential level of the off potential of the transmission controller 335. In addition, the potential level of the low potential side reference potential of the photoelectric conversion unit 334 may be lower than the potential level of the low potential side reference potential of at least one of the pixel signal generation unit 320 and the column ADC 220.

[0139] Figure 12 : is a schematic diagram showing a low potential side reference potential and an off potential used by each unit in the imaging device 100 according to the first embodiment. Figure 12 An example is shown in which the low potential side reference potential and the off potential used by each unit in the imaging device 100 include three potentials having different potential levels. Figure 12 In the example of FIG, the three potentials are set to a ground potential, a first reference potential, and a second reference potential. The ground potential is, for example, 0 V, the first reference potential is a negative potential lower than the ground potential GND, and the second reference potential is a negative potential lower than the second reference potential.

[0140] The first reference potential and the second reference potential are supplied from the negative potential supply unit 235. The negative potential supply unit 235 generates the first reference potential and the second reference potential lower than the ground potential GND using, for example, a charge pump.

[0141] exist Figure 12 In the example of FIG, the low-potential side reference potential of the photoelectric conversion unit 334 is the first reference potential. In addition, the low-potential side reference potential of the address event detector 400, the low-potential side reference potential of the pixel signal generation unit 320, and the low-potential side reference potential of the column ADC 220 are the ground potential GND. The off-potential of the transmission controller 335 is the second reference potential. The transmission controller 335 includes a transmission transistor 331 and an OFG transistor 332, and the off-potential of the transmission controller 335 refers to the potential for turning off the gates of the transmission transistor 331 and the OFG transistor 332.

[0142] exist Figure 12 In the embodiment of the present invention, by setting the low-potential side reference potential of the photoelectric conversion unit 334 to the second reference potential which is a negative potential, the reverse bias voltage of the photodiode (photoelectric conversion element) in the photoelectric conversion unit 334 is increased compared to the case where the low-potential side reference potential of the photoelectric conversion unit 334 is set to the ground potential GND. Therefore, the sensitivity of the photodiode 311 is increased, and dark current can be reduced.

[0143] In addition, the back gates of the transfer transistor 331 and the OFG transistor 332 in the transfer controller 335 can be set to a negative potential Vn. Therefore, compared with the case where the potential is set to the reference potential, it is possible to prevent the threshold voltage of each transistor from becoming higher due to the substrate bias effect and the gate-source voltage of each transistor from becoming zero or less. When the gate-source voltage becomes zero or less, a normal output cannot be obtained due to the circuit configuration of the pixel signal generating unit 320. Therefore, this situation can be suppressed by providing a negative potential Vn to the back gate. As described above, the signal quality of the detection signal can be improved by increasing the sensitivity of the photodiode 311, reducing the dark current, and increasing the threshold voltage.

[0144] exist Figure 12 , the low potential side reference potential (first reference potential) of the address event detector 400 is set to a potential level higher than the low potential side reference potential (first reference potential) of the photoelectric conversion unit 334. If the low potential side reference potential of the address event detector 400 is set to be lower than the low potential side reference potential of the photoelectric conversion unit 334, sufficient reverse bias is not applied to the photodiode in the photoelectric conversion unit 334, and there is a possibility that the response is delayed due to an increase in leakage current or an increase in noise. Figure 12 As shown, by setting the low potential side reference potential of the address event detector 400 to a potential level higher than the low potential side reference potential of the photoelectric conversion unit 334, sufficient reverse bias can be applied to the photodiode, and noise can be reduced and the response speed can be improved.

[0145] When the address event detector 400 performs an address event detection process, the OFG transistor 332 in the transfer controller 335 is turned on. At this time, the transfer transistor 331 needs to be turned off. In addition, when the address event detector 400 detects an address event, the OFG transistor 332 is turned off and the transfer transistor 331 is turned on. When the transfer transistor 331 is turned on, the electrical signal (photocurrent) photoelectrically converted by the photodiode is sent to the pixel signal generation unit 320 via the transfer transistor 331 to generate a pixel signal, and then sent to the column ADC 220 to generate a digital signal.

[0146] In this way, the OFG transistor 332 and the transfer transistor 331 are exclusively turned on / off. In order to reliably make the OFG transistor 332 and the transfer transistor 331 perform exclusive operations, it is desirable to apply a positive potential to the gate of the transistor to be turned on and a negative potential to the gate of the transistor to be turned off. Figure 12 In FIG, the off potential of the transmission controller 335 is set to the second reference potential which is a negative potential.

[0147] Figure 13A and Figure 13Bis an example of specific potential levels of the low potential side reference potential and the off potential provided to each unit in the imaging device 100 according to the first embodiment. Figure 13A shows the potential level in the case where the pass transistor is turned off, and Figure 13B The potential level in the case where the transfer transistor is turned on is shown. In the case where address event detection is performed, Figure 13A , the potential level is set to the potential level. Note that Figure 13A and Figure 13B The potential levels in are examples, and various modifications are conceivable.

[0148] like Figure 13A As shown, when the transfer transistor is turned off, the anode of the photodiode is set to a negative potential of -0.6V. In addition, the gate of the transfer transistor is set to a negative potential of -1.8V. Therefore, the transfer transistor is reliably turned off. The gate of the reset transistor in the pixel signal generation unit 320 is set to 2.2V. Therefore, the reset transistor is turned on, and the charge amount of the floating diffusion layer 324 is initialized. The positive potential side reference potential of the pixel signal generation unit 320 is set to 2.8V.

[0149] Although Figure 13A Although not shown, in the case of performing address event detection, the gate of the OFG transistor is set to approximately 2.2 to 2.8 V. In addition, the low potential side reference potential of the address event detector 400 is set to the ground potential GND (0 V) higher than the anode potential of the photodiode. The positive potential side reference potential of the address event detector 400 is set to 2.2 V.

[0150] like Figure 13B As shown, when the transfer transistor is on, the anode of the photodiode is also set to -0.6 V. In addition, the gate of the transfer transistor is set to 2.2 V. The gate of the reset transistor in the pixel signal generating unit 320 is set to a negative potential of -0.6 V. The drain of the reset transistor is set to 2.2 V. The drain of the amplifying transistor 322 in the pixel signal generating unit 320 is set to 2.8 V.

[0151] Although Figure 13A Although not shown in FIG, the gate of the OFG transistor is set to -1.8 V. The low potential side reference potential of the address event detector 400 is as follows Figure 13A The ground potential GND (0V) in.

[0152] As described above, in the first embodiment, the low potential side reference potential and the shutdown potential used by each unit in the imaging device 100 include three or more types of potentials with different potential levels. Therefore, the operation of each unit in the imaging device 100 can be optimized. For example, since the low potential side reference potential of the photoelectric conversion unit 334 is set to the reference potential, the sensitivity of the photodiode can be improved and the dark current can be reduced. In addition, by setting the low potential side reference potential of the address event detector 400 to be higher than the low potential side reference potential of the photoelectric conversion unit 334, sufficient reverse bias is applied to the photodiode, so that noise reduction and improvement in response speed can be achieved. In addition, by setting the shutdown potential of the transmission controller 335 to a negative potential, the transmission transistor and the OFG transistor can reliably operate exclusively.

[0153] (Second embodiment)

[0154] Figure 14 is a diagram showing a low potential side reference potential and an off potential used by each unit in the imaging device 100 according to the second embodiment. Figure 14 In the example of FIG. 1 , three types of reference potentials having different potential levels are used as the low potential side reference potential and the off potential used by each unit in the imaging device 100, but the potential levels of the three types of reference potentials are different from those of FIG. Figure 12 More specifically, Figure 14 The potential level of the first reference potential is higher than the ground potential GND, and the potential level of the second reference potential is lower than the ground potential GND.

[0155] The second reference potential is supplied from the negative potential supply unit 235. The first reference potential is supplied from a power supply unit (not shown).

[0156] exist Figure 14 In the example of FIG, the low potential side reference potential of the photoelectric conversion unit 334, the low potential side reference potential of the pixel signal generation unit 320, and the low potential side reference potential of the column ADC 220 are the ground potential GND (0V). In addition, the low potential side reference potential of the address event detector 400 is the first reference potential, which is a positive potential. In addition, the off potential of the transmission controller 335 is the second reference potential, which is a negative potential lower than the first reference potential.

[0157] exist Figure 14In this case, since the low-potential side reference potential of the photoelectric conversion unit 334 is set to be lower than the low-potential side reference potential of the address event detector 400, the reverse bias voltage of the photodiode in the photoelectric conversion unit 334 can be sufficiently increased, and noise reduction and improvement in response speed can be achieved. In addition, since the off potential of the transmission controller 335 is set to the second reference potential, which is a negative potential lower than the first reference potential, the transmission transistor and the OFG transistor can reliably operate exclusively.

[0158] Figure 15A and Figure 15B is an example of specific potential levels of the low potential side reference potential and the off potential provided to each unit in the imaging device 100 according to the second embodiment. Figure 15A shows the potential level in the case where the pass transistor is turned off, and Figure 15B The potential level when the transfer transistor is turned on is shown.

[0159] like Figure 15A As shown, when the transfer transistor is turned off, the anode of the photodiode is set to the ground potential GND (0V) as a negative potential. In addition, the gate of the transfer transistor is set to a negative potential of -1.2V. Therefore, the transfer transistor is reliably turned off. The gate of the reset transistor in the pixel signal generating unit 320 is set to 2.8V. Therefore, the reset transistor is turned on, and the amount of charge of the floating diffusion layer 324 is initialized. The positive potential side reference potential of the pixel signal generating unit 320 is set to 2.8V. The low potential side reference potential of the address event detector 400 is set to 0.6V higher than the anode potential of the photodiode. The positive potential side reference potential of the address event detector 400 is set to 2.8V.

[0160] like Figure 15B As shown, when the transfer transistor is turned on, the anode of the photodiode is also set to the ground potential GND (0V). In addition, the gate of the transfer transistor is set to 2.8V. The gate of the reset transistor in the pixel signal generating unit 320 is set to the ground potential GND (0V). The drain of the reset transistor is set to 2.8V. The drain of the amplifying transistor 322 in the pixel signal generating unit 320 is set to 2.8V.

[0161] exist Figure 13A 、 Figure 13B 、 Figure 15A and Figure 15B , 2.2 V and 2.8 V are mixed as the positive potential side reference potential, but these are examples, and the positive potential side reference potential can be set to a specific potential.

[0162] As described above, in the second embodiment, since a positive first reference potential and a negative second reference potential are provided as the low-potential reference potential and the off-potential in addition to the ground potential GND in the imaging device 100, a low-potential reference potential of an optimal voltage level can be set in each unit of the imaging device 100, and the operation of each unit can be optimized. Specifically, by setting the low-potential reference potential of the address event detector 400 higher than the low-potential reference potential of the photoelectric conversion unit 334, a sufficient reverse bias is applied to the photodiode, thereby achieving noise reduction and improved response speed. Furthermore, by setting the off-potential of the transfer controller 335 to a negative potential, the transfer transistor and the OFG transistor can reliably operate exclusively.

[0163] In the second embodiment, only one negative potential is used as the low-potential-side reference potential and the shutdown potential, so the circuit configuration of the negative potential supply unit 235 can be simplified.

[0164] (Third embodiment)

[0165] Figure 16 is a diagram illustrating a low potential side reference potential and an off potential used by each unit in the imaging device 100 according to the third embodiment.

[0166] like Figure 16 As shown, the imaging device 100 according to the third embodiment includes a potential selection unit 336 that switches the low-potential-side reference potential of the photoelectric conversion unit 334. The potential selection unit 336 selects a first reference potential during a period in which the address event detector 400 detects whether the amount of change in the electric signal (photocurrent) photoelectrically converted by the photodiode in the address event detector 400 exceeds a predetermined threshold value, and selects a second reference potential having a higher potential level than the first reference potential during a period in which the analog-to-digital converter converts the pixel signal into a digital signal.

[0167] The low potential side reference potential and the off potential used by each unit of the imaging device 100 according to the third embodiment are respectively the first reference potential and the second reference potential having different potential levels. That is, the third embodiment has one less reference potential than the first and second embodiments.

[0168] In the third embodiment, the second reference potential is, for example, the ground potential GND (0 V), and the first reference potential is a negative potential lower in potential level than the ground potential GND. The first reference potential is supplied from the negative potential supply unit 235 .

[0169] exist Figure 16In the imaging device 100, the low-side reference potential of the address event detector 400, the low-side reference potential of the pixel signal generating unit 320, and the low-side reference potential of the column ADC 220 are the ground potential GND (second reference potential). The off potential of the transmission controller 335 is a negative potential (first reference potential).

[0170] The address event detector 400 needs to quickly detect address events based on the electrical signal photoelectrically converted by the photodiode in the photoelectric conversion unit 334. Therefore, during the period in which the address event detector 400 performs the address event detection operation, the low-potential side reference potential of the photoelectric conversion unit 334 is lowered to a negative potential to improve the sensitivity of the photodiode and reduce dark current. On the other hand, when the address event detector 400 detects an address event, the pixel signal generation unit 320 generates a pixel signal. However, since it is not necessary to increase the sensitivity of the photodiode during this period, the low-potential side reference potential of the receiving unit is set to the ground potential GND, thereby reducing power consumption.

[0171] As described above, in the third embodiment, since the low-potential side reference potential of the photoelectric conversion unit 334 is switched between the case of performing address event detection and the case of generating pixel signals, the sensitivity of the photodiode during address event detection can be improved and the dark current can be reduced, and the power consumption when generating pixel signals can be reduced.

[0172] (Fourth embodiment)

[0173] In the above-mentioned first to third embodiments, the description has been made of Figure 6 The imaging device 100 includes the address event detector 400, but the internal configuration of the address event detector 400 is not necessarily limited to Figure 6 . Figure 17 4 is a block diagram showing a second configuration example of the address event detector 400. Figure 17 As shown, the address event detector 400 according to the present configuration example includes a storage unit 460 and a controller 470 in addition to the current-voltage converter 410 , the buffer 420 , the subtractor 430 , the quantizer 440 , and the transmission unit 450 .

[0174] The storage unit 460 is provided between the quantizer 440 and the transmission unit 450, and accumulates the output of the quantizer 440 (i.e., the comparison result of the comparator 441 in the quantizer 440) based on the sampling signal supplied from the controller 470. The storage unit 460 may be a sampling circuit such as a switch, plastic, or capacitor, or may be a digital memory circuit such as a latch or a flip-flop.

[0175] The controller 470 sets the predetermined threshold voltage V thSupplied to the inverting (-) input terminal of the comparator 441. The threshold voltage V supplied from the controller 470 to the comparator 441 th Different voltage values ​​can be provided in a time-division manner. For example, the controller 470 supplies a threshold voltage V corresponding to a turn-on event indicating that the amount of change in the photocurrent exceeds the upper threshold at different timings. th1 and the threshold voltage V corresponding to the disconnection event indicating that the change amount falls below the lower threshold th2 , so that one comparator 441 can detect multiple types of address events.

[0176] For example, at the threshold voltage V corresponding to the disconnection event th2 During the period of time supplied from the controller 470 to the inverting (-) input terminal of the comparator 441, the storage unit 460 may use the threshold voltage V corresponding to the turn-on event. th1 The comparison result of the comparator 441 is accumulated. It should be noted that the storage unit 460 may be inside the pixel 30 or may be outside the pixel 30. In addition, the storage unit 460 is not an essential configuration element of the address event detector 400. That is, the storage unit 460 may be omitted.

[0177] [Image Forming Apparatus 100 According to Second Configuration Example (Scanning Method)]

[0178] Including the above Figure 6 The imaging device 10020 of the first configuration example of the address event detector 400 shown in FIG is an asynchronous imaging device 100 that reads events using an asynchronous reading method. However, the event reading method is not limited to the asynchronous reading method, but may be a synchronous reading method. The imaging device 100 to which the synchronous reading method is applied is the same scanning type imaging device 100 as a general imaging device 100 that performs imaging at a predetermined frame rate.

[0179] Figure 18 10 is a block diagram showing an example of the configuration of an imaging device 10020 according to a second configuration example, that is, a scanning-type imaging device 100 is used as the imaging device 100 in the imaging system 10 to which the technology according to the present disclosure is applied.

[0180] like Figure 18 As shown in , the imaging device 100 according to the second configuration example of the imaging device 10020 as the present disclosure includes a pixel array unit 21 , a driving unit 22 , a signal processing unit 25 , a reading area selection unit 27 , and a signal generating unit 221 .

[0181] The pixel array unit 21 includes a plurality of pixels 30. The plurality of pixels 30 outputs output signals in response to the selection signal of the read region selection unit 27. For example, Figure 7As shown, each of the plurality of pixels 30 may have a quantizer in the pixel. The plurality of pixels 30 output an output signal corresponding to the amount of change in light intensity. Figure 18 As shown, a plurality of pixels 30 may be arranged two-dimensionally in a matrix.

[0182] The driving unit 22 drives each of the plurality of pixels 30 to output a pixel signal generated in each pixel 30 to the signal processing unit 25. It should be noted that the driving unit 22 and the signal processing unit 25 are circuit units for acquiring gradient information. Therefore, in the case of acquiring only event information, the driving unit 22 and the signal processing unit 25 may not be provided.

[0183] The read region selection unit 27 selects some of the plurality of pixels 30 included in the pixel array unit 21. For example, the read region selection unit 27 selects any one or more rows from the rows included in the structure corresponding to the two-dimensional matrix of the pixel array unit 21. The read region selection unit 27 sequentially selects one or more rows in accordance with a preset cycle. In addition, the read region selection unit 27 may determine the selected region in response to a request from each pixel 30 of the pixel array unit 21.

[0184] Based on the output signals of the pixels selected by the read area selection unit 27, the signal generation unit 221 generates event signals corresponding to active pixels in the selected pixels where an event has been detected. An event is an event in which light intensity changes. An active pixel is a pixel where the change in light intensity corresponding to the output signal exceeds or falls below a preset threshold. For example, the signal generation unit 221 compares the pixel output signals with a reference signal. If the output signals are greater than or less than the reference signal, the signal generation unit 221 detects active pixels that output the output signals and generates event signals corresponding to the active pixels.

[0185] The signal generation unit 221 may include, for example, a column selection circuit that arbitrates signals entering the signal generation unit 221. Furthermore, the signal generation unit 221 may be configured to output not only information of active pixels that have detected an event, but also information of inactive pixels that have not detected an event.

[0186] The address information and time stamp information (e.g., (X, Y, T)) of the active pixel where the event has been detected are output from the signal generating unit 221 through the output line 15. However, the data output from the signal generating unit 221 may be not only the address information and time stamp information but also information in a frame format (e.g., (0, 0, 1, 0, ...)).

[0187] [Configuration example of chip structure]

[0188] As a chip (semiconductor integrated circuit) structure of the imaging device 10020 according to the above-mentioned first configuration example or second configuration example, Figure 2 As shown, a stacked chip structure can be used. The stacked chip structure, that is, the stacked structure has a structure in which at least two chips, a light receiving chip 201 as a first chip and a detection chip 202 as a second chip, are stacked. Then, Figure 4 In the circuit configuration of the pixel 30 shown, each light receiving unit 330 is arranged on the light receiving chip 201, and all components except the light receiving element 311 and components of other circuit parts of the pixel 30 are arranged on the detection chip 202. The light receiving chip 201 and the detection chip 202 are electrically connected via a connection portion such as a via (VIA), Cu-Cu bonding, or a bump.

[0189] It should be noted that here, an example has been given in which the light receiving element 311 is arranged on the light receiving chip 201 and elements other than the light receiving element 311, elements of other circuit parts of the pixel 30, etc. are arranged on the detection chip 202, but the present invention is not limited to this configuration example.

[0190] For example, in Figure 4 In the circuit configuration of the pixel 30 shown, each element of the light receiving unit 330, the reset transistor 321 of the pixel signal generating unit 320, and the floating diffusion layer 324 can be arranged in the light receiving chip 201, and the other elements can be arranged in the detection chip 202. Alternatively, some elements configuring the address event detector 400 can be arranged on the light receiving chip 201 together with each element of the light receiving unit 330, etc.

[0191] [Configuration example of column processing unit]

[0192] Figure 9 Although a configuration example is shown in which the analog-to-digital converters (ADCs) 230 are provided in the column ADCs 220 in a one-to-one correspondence with the pixel columns of the pixel array unit 21, the present invention is not limited to this configuration example. For example, the analog-to-digital converters (ADCs) 230 may be arranged in units of a plurality of pixel columns, and the analog-to-digital converters (ADCs) 230 may be used in a time-division manner between the plurality of pixel columns.

[0193] The analog-to-digital converter (ADC) 230 converts the analog pixel signal SIG supplied via the vertical signal line VSL into a digital signal having a larger number of bits than the detection signal of the above-mentioned address event. For example, when the detection signal of the address event is 2 bits, the pixel signal is converted into a digital signal of 3 bits or more (16 bits, etc.). The analog-to-digital converter (ADC) 230 supplies the digital signal generated by the analog-to-digital conversion to the signal processing unit 25.

[0194] [About the noise incident]

[0195] Incidentally, the imaging device 10020 according to the first configuration example is an asynchronous imaging device 100 called DVS, which includes, for each pixel 30, a detector (i.e., an address event detector 400) that detects, in real time for each pixel address, the amount of light of the pixel exceeding a predetermined threshold as an address event.

[0196] In the imaging device 100 according to the asynchronous first configuration example, when some event (i.e., a real event) initially occurs in a scene, data generated by the occurrence of the real event is acquired. However, in the asynchronous imaging device 100, even in a scene where no real event has occurred, there are cases where data is wastefully acquired due to noise events (false events) such as sensor noise. As a result, not only is a noise signal read, but the throughput of signal output is also reduced.

[0197] <Application Examples of Technology According to the Present Disclosure>

[0198] The technology disclosed herein can be applied to a variety of products. More specific application examples will be described below. For example, the technology disclosed herein can be implemented as a distance measuring device mounted on any type of mobile object, such as an automobile, electric vehicle, hybrid electric vehicle, motorcycle, bicycle, personal mobility, aircraft, drone, ship, robot, construction machinery, and agricultural machinery (tractor).

[0199] [Mobile Object]

[0200] Figure 19 7000 is a block diagram showing a schematic configuration example of a vehicle control system 7000, which is an example of a mobile control system to which the technology according to the present disclosure can be applied. The vehicle control system 7000 includes a plurality of electronic control units connected via a communication network 7010. Figure 19 In the example shown, a vehicle control system 7000 includes a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, a vehicle exterior information detection unit 7400, a vehicle interior information detection unit 7500, and an integrated control unit 7600. A communication network 7010 connecting the plurality of control units may be, for example, an in-vehicle communication network conforming to any standard, such as a controller area network (CAN), a local interconnect network (LIN), a local area network (LAN), or FlexRay (registered trademark).

[0201] Each control unit includes a microcomputer (processor) that performs arithmetic processing according to various programs, a storage unit that stores the programs executed by the microcomputer, parameters for various calculations, etc., and a drive circuit that drives various devices to be controlled. Each control unit includes a network I / F for communicating with other control units via the communication network 7010, and a communication I / F for communicating with devices, sensors, etc. inside and outside the vehicle through wired communication or wireless communication. Figure 19 76, as a functional configuration of integrated control unit 7600, a microcomputer 7610, a general-purpose communication I / F 7620, a dedicated communication I / F 7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I / F 7660, an audio / video output unit 7670, an in-vehicle network I / F 7680, and a storage unit 7690 are shown. Other control units similarly include a microcomputer, a communication I / F, a storage unit, and the like.

[0202] The drive system control unit 7100 controls the operation of devices related to the vehicle's drive system according to various programs. For example, the drive system control unit 7100 functions as a control device for a drive force generating device such as an internal combustion engine or a drive motor for generating the vehicle's drive force, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the vehicle's steering angle, a braking device for generating the vehicle's braking force, and the like. The drive system control unit 7100 may also function as a control device for systems such as an anti-lock braking system (ABS) or an electronic stability control (ESC).

[0203] Vehicle state detector 7110 is connected to drive system control unit 7100. Vehicle state detector 7110 includes, for example, at least one of a gyroscopic sensor for detecting the angular velocity of the vehicle body's axial rotational motion, an acceleration sensor for detecting vehicle acceleration, and sensors for detecting the amount of accelerator pedal operation, brake pedal operation, steering wheel angle, engine speed, wheel speed, and the like. Drive system control unit 7100 performs computational processing using the signals input from vehicle state detector 7110 to control the internal combustion engine, drive motor, electric power steering, brake system, and the like.

[0204] The body system control unit 7200 controls the operation of various devices installed on the vehicle body according to various programs. For example, the body system control unit 7200 functions as a control device for a keyless entry system, a smart key system, power windows, or various lights such as headlights, taillights, brake lights, blinkers, and fog lights. In this case, radio waves transmitted from a portable device that replaces keypads or signals from various switches can be input to the body system control unit 7200. The body system control unit 7200 receives these radio waves or signals and controls the vehicle's door locks, power windows, lights, and other functions.

[0205] Battery control unit 7300 controls secondary battery 7310, which serves as a power source for driving the electric motor, according to various programs. For example, information such as battery temperature, battery output voltage, or remaining battery capacity is input to battery control unit 7300 from a battery device including secondary battery 7310. Battery control unit 7300 performs arithmetic operations using these signals and controls the temperature of secondary battery 7310 or a cooling device included in the battery device.

[0206] The vehicle exterior information detection unit 7400 detects information outside the vehicle on which the vehicle control system 7000 is installed. For example, at least one of the imaging unit 7410 and the vehicle exterior information detector 7420 is connected to the vehicle exterior information detection unit 7400. The imaging unit 7410 includes at least one of a time-of-flight (ToF) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The vehicle exterior information detector 7420 includes at least one of an environmental sensor for detecting the current climate or weather and a surrounding information detection sensor for detecting another vehicle, obstacles, pedestrians, and the like around the vehicle on which the vehicle control system 7000 is installed.

[0207] For example, the environmental sensor may be at least one of a raindrop sensor for detecting rain, a fog sensor for detecting fog, a sunlight sensor for detecting sunlight levels, and a snow sensor for detecting snowfall. The surrounding information detection sensor may be at least one of an ultrasonic sensor, a radar device, a light detection and ranging, and a laser imaging detection and ranging (LIDAR) device. The imaging unit 7410 and the vehicle exterior information detector 7420 may be provided as independent sensors or devices, or may be provided as a device in which multiple sensors or devices are integrated.

[0208] here, Figure 20 is a diagram illustrating examples of the installation locations of the imaging unit 7410 and the vehicle exterior information detector 7420. Imaging units 7910, 7912, 7914, 7916, and 7918 are installed, for example, at at least one of the front nose, side mirrors, rear bumper, rear door, and upper portion of the windshield within the vehicle 7900. Imaging unit 7910 located at the front nose and imaging unit 7918 located at the upper portion of the windshield within the vehicle primarily capture images of the front of the vehicle 7900. Imaging units 7912 and 7914 located at the side mirrors primarily capture images of the sides of the vehicle 7900. Imaging unit 7916 located on the rear bumper or rear door primarily captures images of the rear of the vehicle 7900. Imaging unit 7918 located at the upper portion of the windshield within the vehicle primarily detects vehicles ahead, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.

[0209] Please note that Figure 20 The following diagram illustrates examples of the imaging ranges of the respective imaging units 7910, 7912, 7914, and 7916. Imaging range a indicates the imaging range of imaging unit 7910, located at the front nose; imaging ranges b and c indicate the imaging ranges of imaging units 7912 and 7914, respectively, located at the side mirrors; and imaging range d indicates the imaging range of imaging unit 7916, located at the rear bumper or rear door. For example, by overlapping the image data captured by imaging units 7910, 7912, 7914, and 7916, it is possible to obtain a bird's-eye view image of vehicle 7900 viewed from above.

[0210] Exterior vehicle information sensors 7920, 7922, 7924, 7926, 7928, and 7930, located on the front, rear, sides, corners, and upper portion of the windshield within vehicle 7900, may be, for example, ultrasonic sensors or radar devices. Exterior vehicle information sensors 7920, 7926, and 7930, located on the front nose, rear bumper, rear door, and upper portion of the windshield within vehicle 7900, may be, for example, LIDAR devices. These exterior vehicle information sensors 7920 to 7930 are primarily used to detect vehicles ahead, pedestrians, obstacles, and the like.

[0211] return Figure 19 , will continue to describe. The vehicle outside information detection unit 7400 enables the imaging unit 7410 to capture images outside the vehicle and receive the captured image data. In addition, the vehicle outside information detection unit 7400 receives detection information from the connected vehicle outside information detection unit 7420. In the case where the vehicle outside information detection unit 7420 is an ultrasonic sensor, a radar device, or a LIDAR device, the vehicle outside information detection unit 7400 transmits ultrasonic waves, electromagnetic waves, etc., and receives information of the received reflected waves. The vehicle outside information detection unit 7400 can perform object detection processing or distance detection processing of people, vehicles, obstacles, signs, text on the road surface, etc. based on the received information. The vehicle outside information detection unit 7400 can perform environmental recognition processing to identify rainfall, fog, road conditions, etc. based on the received information. The vehicle outside information detection unit 7400 can calculate the distance to objects outside the vehicle based on the received information.

[0212] Additionally, the vehicle exterior information detection unit 7400 can also perform image recognition processing or distance detection based on the received image data to identify people, vehicles, obstacles, signs, text on the road, etc. The vehicle exterior information detection unit 7400 can perform processing such as distortion correction and alignment on the received image data, and synthesize image data captured by different imaging units 7410 to generate bird's-eye views, panoramic images, etc. The vehicle exterior information detection unit 7400 can also use the image data captured by different imaging units 7410 to perform viewpoint transformation processing.

[0213] The in-vehicle information detection unit 7500 detects information about the interior of the vehicle. For example, a driver state detector 7510 that detects the driver's state is connected to the in-vehicle information detection unit 7500. The driver state detector 7510 may include a camera that captures the driver's image, a biometric sensor that detects the driver's biometric information, a microphone that collects audio from the vehicle interior, and the like. For example, the biometric sensor is provided on a seat surface, a steering wheel, or the like, and detects biometric information of a passenger sitting on the seat or the driver holding the steering wheel. The in-vehicle information detection unit 7500 can calculate the driver's fatigue or concentration based on the detection information input from the driver state detector 7510, or can determine whether the driver is dozing off. The in-vehicle information detection unit 7500 can perform processing such as noise cancellation on the collected audio signal.

[0214] Integrated control unit 7600 controls the overall operation of vehicle control system 7000 according to various programs. Input unit 7800 is connected to integrated control unit 7600. Input unit 7800 is implemented by, for example, a touch panel, buttons, microphone, switch, or lever operable by a passenger for input. Data obtained by performing audio recognition on audio input by the microphone can be input to integrated control unit 7600. Input unit 7800 can be, for example, a remote control device using infrared or other radio waves, or an externally connected device that corresponds to the operation of vehicle control system 7000, such as a mobile phone or personal digital assistant (PDA). Input unit 7800 can be, for example, a camera, in which case the passenger can input information through gestures. Alternatively, data obtained by detecting the movement of a wearable device worn by the passenger can be input. Furthermore, input unit 7800 can include, for example, an input control circuit that generates an input signal based on information input by the passenger using input unit 7800 and outputs the input signal to integrated control unit 7600. By operating the input unit 7800 , an occupant or the like inputs various data to the vehicle control system 7000 or instructs processing operations.

[0215] The storage unit 7690 may include a read-only memory (ROM) that stores various programs to be executed by the microcomputer and a random access memory (RAM) that stores various parameters, calculation results, sensor values, etc. In addition, the storage unit 7690 may be implemented by a magnetic storage device such as a hard disk drive (HDD), a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like.

[0216] The general communication I / F 7620 is a general communication I / F that mediates communications with various devices present in the external environment 7750. The general communication I / F 7620 can implement a cellular communication protocol such as Global System for Mobile Communications (GSM) (registered trademark), WiMAX, Long Term Evolution (LTE), or Advanced LTE (LTE-A), or another wireless communication protocol such as wireless LAN (also known as Wi-Fi (registered trademark)) or Bluetooth (registered trademark). The general communication I / F 7620 can be connected to a device (e.g., an application server or a control server) present on an external network (e.g., the Internet, a cloud network, or a company-specific network) via, for example, a base station or an access point. In addition, the general communication I / F 7620 can be connected to a terminal (e.g., a driver's terminal, a pedestrian or a store's terminal, or a machine-type communication (MTC) terminal) present near the vehicle using, for example, peer-to-peer (P2P) technology.

[0217] Dedicated communication I / F 7630 is a communication I / F that supports communication protocols developed for use in vehicles. For example, dedicated communication I / F 7630 can implement standard protocols such as Wireless Access in Vehicular Environments (WAVE) (a combination of the lower layer IEEE802.11p and the upper layer IEEE802.1609), Dedicated Short Range Communication (DSRC), or cellular communication protocols. Dedicated communication I / F 7630 typically implements V2X communication, a concept that includes one or more of vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-home communication, and vehicle-to-pedestrian communication.

[0218] Positioning unit 7640 receives a global navigation satellite system (GNSS) signal (e.g., a global positioning system (GPS) signal from a GPS satellite) from a GNSS satellite, performs positioning, and generates position information including the latitude, longitude, and altitude of the vehicle. Note that positioning unit 7640 can specify the current position by exchanging signals with a wireless access point, or can obtain position information from a terminal such as a mobile phone, PHS, or a smartphone with a positioning function.

[0219] The beacon receiving unit 7650 receives radio waves or electromagnetic waves transmitted from, for example, a wireless station installed on a road, and obtains information such as the current position, traffic congestion, closed roads, required time, etc. Note that the function of the beacon receiving unit 7650 may be included in the above-mentioned dedicated communication I / F 7630.

[0220] The onboard device I / F 7660 is a communication interface that mediates connections between the microcomputer 7610 and various onboard devices 7760 present in the vehicle. The onboard device I / F 7660 can establish a wireless connection using a wireless communication protocol such as wireless LAN, Bluetooth (registered trademark), near field communication (NFC), or wireless USB (WUSB). In addition, the onboard device I / F 7660 can establish a wired connection such as a universal serial bus (USB), a high-definition multimedia interface (HDMI) (registered trademark), or a mobile high-definition link (MHL) via a connection terminal (and, if necessary, a cable) not shown. The onboard device 7760 may include, for example, at least one of a mobile device or wearable device owned by a passenger and an information device carried in or attached to the vehicle. In addition, the onboard device 7760 may include a navigation device that searches for a route to an arbitrary destination. The onboard device I / F 7660 exchanges control signals or data signals with these onboard devices 7760.

[0221] The in-vehicle network I / F 7680 is an interface that coordinates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network I / F 7680 transmits and receives signals and the like according to a predetermined protocol supported by the communication network 7010.

[0222] The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 according to various programs based on information acquired via at least one of the general communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the vehicle-mounted device I / F 7660, and the vehicle network I / F 7680. For example, the microcomputer 7610 can calculate control target values ​​for the driving force generation device, the steering mechanism, or the braking device based on the acquired information about the interior and exterior of the vehicle, and output control commands to the drive system control unit 7100. For example, the microcomputer 7610 can perform cooperative control to implement functions of an advanced driver assistance system (ADAS), including collision avoidance or impact mitigation of vehicles, following driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, and the like. In addition, the microcomputer 7610 can perform cooperative control for purposes such as autonomous driving by controlling the driving force generating device, steering mechanism, braking device, etc. based on the information obtained around the vehicle, in which the vehicle travels autonomously without relying on the driver's operation.

[0223] Microcomputer 7610 can generate three-dimensional distance information between the vehicle and objects such as surrounding structures or people based on information acquired via at least one of general communication I / F 7620, dedicated communication I / F 7630, positioning unit 7640, beacon receiving unit 7650, in-vehicle device I / F 7660, and in-vehicle network I / F 7680, and create local map information including surrounding information of the vehicle's current location. Furthermore, microcomputer 7610 can predict danger (such as a vehicle collision, the approach of a pedestrian, etc.) or entry into a closed road based on the acquired information and generate a warning signal. The warning signal can be, for example, a signal for generating a warning sound or turning on a warning light.

[0224] The audio image output unit 7670 transmits an output signal of at least one of audio and image to an output device capable of visually or auditorily notifying an occupant of the vehicle or the outside of the vehicle of information. Figure 19 In the example of , audio speakers 7710, display units 7720 and instrument panels 7730 are shown as output devices. Display unit 7720 may include, for example, at least one of an onboard display and a head-up display. Display unit 7720 may have an augmented reality (AR) display function. The output device may be another device different from these devices, such as a wearable device, such as a headset or glasses-type display worn by a passenger, a projector or a lamp. In the case where the output device is a display device, the display device visually displays the results obtained by the various processes performed by the microcomputer 7610 or information received from another control unit in various formats (such as text, images, tables and graphics). In addition, in the case where the output device is an audio output device, the audio output device converts an audio signal including reproduced audio data, audio data, etc. into an analog signal and audibly outputs the analog signal.

[0225] It should be noted that Figure 19 In the example shown in , at least two control units connected via the communication network 7010 can be integrated into one control unit. Optionally, each control unit may include multiple control units. In addition, the vehicle control system 7000 may include another control unit (not shown). In addition, in the above description, some or all of the functions performed by any control unit can be provided to another control unit. That is to say, as long as information is sent and received via the communication network 7010, predetermined arithmetic processing can be performed by any control unit. Similarly, a sensor or device connected to any control unit can be connected to another control unit, and multiple control units can send and receive detection information to each other via the communication network 7010.

[0226] An example of a vehicle 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 units 7910, 7912, 7914, 7916, and 7918, the vehicle exterior information detectors 7920, 7922, 7924, 7926, 7928, and 7930, the driver state detector 7510, and the like in the above configuration. Specifically, the imaging device 100 of the present disclosure includes Figure 1 The imaging system 10 in FIG. 1 can be applied to these imaging units and detectors. Then, by applying the technology according to the present disclosure, the influence of noise events such as sensor noise can be mitigated, and the occurrence of real events can be reliably and quickly sensed, thereby achieving safe vehicle driving.

[0227] It should be noted that the present disclosure can have the following configurations.

[0228] (1) An imaging device comprising:

[0229] a photoelectric conversion unit including a plurality of photoelectric conversion elements, each of the plurality of photoelectric conversion elements performing photoelectric conversion on incident light to generate an electrical signal;

[0230] a detector configured to output a detection signal indicating whether an amount of change in an electric signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value;

[0231] a pixel signal generating unit configured to generate a pixel signal based on the electrical signal;

[0232] a transmission controller configured to perform control of transmitting the electrical signal to the pixel signal generating unit; and

[0233] an analog-to-digital converter configured to convert the pixel signal into a digital signal;

[0234] Among them, the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shutdown potential of the transmission controller include three or more potentials with different potential levels.

[0235] (2) The imaging device according to (1), wherein a potential level of the low potential side reference potential of the photoelectric conversion unit is lower than a potential level of the low potential side reference potential of the detector.

[0236] (3) The imaging device according to (1) or (2), wherein a potential level of the low potential side reference potential of the photoelectric conversion unit is higher than a potential level of an off potential of a transmission controller.

[0237] (4) An imaging device according to any one of (1) to (3), wherein the potential level of the low potential side reference potential of the photoelectric conversion unit is lower than the potential level of the low potential side reference potential of at least one of the pixel signal generation unit and the analog-to-digital converter.

[0238] (5) An imaging device according to any one of (1) to (4), wherein at least one of the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shutdown potential of the transmission controller is a ground potential, at least one of the others is a first reference potential having a potential level lower than the ground potential, and at least one of the others is a second reference potential having a potential level lower than the first reference potential.

[0239] (6) The imaging device according to (5), wherein the low potential side reference potential of the photoelectric conversion unit is the second reference potential,

[0240] The detector low potential side reference potential, the low potential side reference potential of the pixel signal generating unit and the low potential side reference potential of the analog-to-digital converter are ground potentials, and the off potential of the transmission controller is a second reference potential.

[0241] (7) The imaging device according to (5) or (6), wherein the ground potential is 0 V,

[0242] The first reference potential is a negative potential; and

[0243] The second reference potential is a negative potential having a potential level lower than that of the first reference potential.

[0244] (8) An imaging device according to any one of (1) to (3), wherein the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the pixel signal generation unit, and the low potential side reference potential of the analog-to-digital converter are substantially equal.

[0245] (9) An imaging device according to any one of (1) to (3) and (8), wherein at least one of the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shutdown potential of the transmission controller is a ground potential, at least one of the others is a first reference potential having a potential level lower than the ground potential, and at least one of the other potentials is a second reference potential having a potential level higher than the ground potential.

[0246] (10) The imaging device according to (9), wherein the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the pixel signal generation unit, and the low potential side reference potential of the analog-to-digital converter are ground potentials,

[0247] The low potential side reference potential of the detector is a first reference potential; and

[0248] The off potential of the transmission controller is the second reference potential.

[0249] (11) The imaging device according to (9) or (10), wherein the ground potential is 0 V,

[0250] The first reference potential is a positive potential; and

[0251] The second reference potential is a negative potential.

[0252] (12) An imaging device comprising:

[0253] a photoelectric conversion unit including a plurality of photoelectric conversion elements, each of the plurality of photoelectric conversion elements performing photoelectric conversion on incident light to generate an electrical signal;

[0254] a detector configured to output a detection signal indicating whether an amount of change in the electric signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value;

[0255] a pixel signal generating unit configured to generate a pixel signal based on the electrical signal;

[0256] a transmission controller configured to perform control to transmit the electric signal to the pixel signal generating unit;

[0257] an analog-to-digital converter configured to convert the pixel signal into a digital signal; and

[0258] a potential selection unit configured to switch a low potential side reference potential of the photoelectric conversion unit;

[0259] (13) The imaging device according to (12), wherein the analog-to-digital converter converts the pixel signal into a digital signal when the detector detects that the amount of change exceeds a predetermined threshold; and

[0260] The potential selection unit selects a first reference potential during a period when the detector detects whether the change amount exceeds a predetermined threshold, and selects a second reference potential having a potential level higher than that of the first reference potential during a period when the analog-to-digital converter converts the pixel signal into a digital signal.

[0261] (14) The imaging device according to (13), wherein the first reference potential is a negative potential, and

[0262] The second reference potential is ground potential.

[0263] (15) An imaging device according to any one of (12) to (14), wherein the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shutdown potential of the transmission controller include two or more potentials with different potential levels.

[0264] (16) The imaging device according to any one of (12) to (15), wherein the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, and the low potential side reference potential of the analog-to-digital converter are ground potentials, and

[0265] The off potential of the transmission controller is a negative potential.

[0266] (17) The imaging device according to any one of (5) to (7), (9) to (11), and (13), further including a potential generating unit configured to generate at least one of the first reference potential and the second reference potential.

[0267] (18) The imaging device according to any one of (1) to (17), wherein at least the detector is arranged on a second substrate stacked on a first substrate on which the photoelectric conversion unit is arranged.

[0268] (19) The imaging device according to any one of (1) to (18), wherein the back gate of the transistor in the transfer controller is set to a potential at the same potential level as the low potential side reference potential of the photoelectric conversion unit.

[0269] (20) An electronic device comprising:

[0270] an imaging device configured to output captured image data; and

[0271] a processor configured to perform predetermined signal processing on the image data;

[0272] The imaging device includes:

[0273] a photoelectric conversion unit including a plurality of photoelectric conversion elements, each of the plurality of photoelectric conversion elements performing photoelectric conversion on incident light to generate an electrical signal;

[0274] a detector configured to output a detection signal indicating whether an amount of change in an electric signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value;

[0275] a pixel signal generating unit configured to generate a pixel signal based on the electrical signal;

[0276] a transmission controller configured to perform control of transmitting the electrical signal to the pixel signal generating unit; and

[0277] an analog-to-digital converter configured to convert the pixel signal into a digital signal; and

[0278] Among them, the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shutdown potential of the transmission controller include three or more potentials with different potential levels.

[0279] (21) An imaging method comprising:

[0280] The step of photoelectrically converting incident light to generate an electrical signal using a plurality of photoelectric conversion elements;

[0281] a step of outputting a detection signal indicating whether the amount of change in the electric signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value;

[0282] The step of transmitting an electrical signal;

[0283] a step of generating a pixel signal based on the transmitted electrical signal; and

[0284] The step of converting pixel signals into digital signals;

[0285] wherein the low potential side reference potential in photoelectric conversion, the low potential side reference potential in outputting a detection signal, the low potential side reference potential in generating a pixel signal, the low potential side reference potential in converting a pixel signal into a digital signal, and the off potential in transmitting an electrical signal include three or more potentials having different potential levels; and

[0286] Using these potentials, the steps of generating an electric signal, outputting a detection signal, transmitting the electric signal, generating a pixel signal, and converting the detection signal into a digital signal are performed.

[0287] The various aspects of the present disclosure are not limited to the above-described embodiments, but include various modifications that can be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the above-described contents. That is, various additions, modifications, and partial deletions may be made without departing from the conceptual concept and spirit of the present disclosure obtained from the contents defined in the claims and their equivalents.

[0288] Reference Signs List

[0289] 100 Imaging Device

[0290] 110 Imaging Lens

[0291] 120 recording units

[0292] 130 controller

[0293] 200 Solid-state image sensing device

[0294] 201 optical receiver chip

[0295] 202 Detection Chip

[0296] 211 drive circuit

[0297] 212 Signal Processing Unit

[0298] 213 Arbitrator

[0299] 220 columns ADC

[0300] 221 Signal Generation Unit

[0301] 223 Reference signal generation unit

[0302] 222 output unit

[0303] 230 ADC

[0304] 235 Negative potential supply unit

[0305] 236 Comparator

[0306] 237 Counter

[0307] 238 switch

[0308] 239 Memory

[0309] 240 Differential Amplifier Circuit

[0310] 241, 242, 412 P-type transistors

[0311] 243, 244, 245, 411, 413 N-type transistors

[0312] 250 counter

[0313] 300 pixel array unit

[0314] 310 pixel blocks

[0315] 311 pixels

[0316] 312 normal pixels

[0317] 313 Address event detection pixel

[0318] 320 pixel signal generation unit

[0319] 321 Reset transistor

[0320] 322 Amplifier Transistor

[0321] 323 Select transistor

[0322] 324 floating diffusion layer

[0323] 330 light receiving unit

[0324] 331 Pass Transistor

[0325] 332 OFG transistor

[0326] 333 Photoelectric conversion element

[0327] 334 Photoelectric conversion unit

[0328] 335 Transmission Controller

[0329] 400 Address Event Detector

[0330] 410 Current-Voltage Converter

[0331] 420 Buffer

[0332] 430 Subtractor

[0333] 431, 433 capacitors

[0334] 432 Inverter

[0335] 434 switch

[0336] 440 Quantizer

[0337] 441 Comparator

[0338] 450 transmission units

[0339] 12031 Imaging unit.

Claims

1. An imaging device comprising: a photoelectric conversion unit including a plurality of photoelectric conversion elements, each of the plurality of photoelectric conversion elements photoelectrically converting incident light to generate an electrical signal; a detector configured to output a detection signal indicating whether a change amount of an electrical signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value; a pixel signal generating unit configured to generate a pixel signal based on the electrical signal; a transmission controller configured to perform control of transmitting the electrical signal to the pixel signal generating unit; as well as an analog-to-digital converter configured to convert the pixel signal into a digital signal, wherein the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generation unit, the low potential side reference potential of the analog-to-digital converter, and the off potential of the transmission controller include three or more potentials having different potential levels, The low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the pixel signal generation unit, and the low potential side reference potential of the analog-to-digital converter are equal.

2. The imaging device according to claim 1, wherein A potential level of the low potential side reference potential of the photoelectric conversion unit is lower than a potential level of the low potential side reference potential of the detector.

3. The imaging device according to claim 1, wherein The potential level of the low potential side reference potential of the photoelectric conversion unit is higher than the potential level of the off potential of the transmission controller.

4. The imaging device according to claim 1, wherein At least one of the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shutdown potential of the transmission controller is a ground potential, at least one of the others is a first reference potential having a potential level lower than the ground potential, and at least one of the others is a second reference potential having a potential level lower than the first reference potential.

5. The imaging device according to claim 4, wherein The ground potential is 0V, The first reference potential is a negative potential, and The second reference potential is a negative potential having a potential level lower than that of the first reference potential.

6. The imaging device according to claim 1, wherein At least one of the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter, and the shutdown potential of the transmission controller is a ground potential, at least one of the others is a first reference potential having a potential level higher than the ground potential, and at least one of the others is a second reference potential having a potential level lower than the ground potential.

7. The imaging device according to claim 6, wherein the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the pixel signal generation unit, and the low potential side reference potential of the analog-to-digital converter are the ground potential, The low potential side reference potential of the detector is the first reference potential, and The off potential of the transmission controller is the second reference potential.

8. The imaging device according to claim 6, wherein The ground potential is 0V, The first reference potential is a positive potential, and The second reference potential is a negative potential.

9. An imaging device comprising: a photoelectric conversion unit including a plurality of photoelectric conversion elements, each of the plurality of photoelectric conversion elements photoelectrically converting incident light to generate an electrical signal; a detector configured to output a detection signal indicating whether a change amount of an electrical signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value; a pixel signal generating unit configured to generate a pixel signal based on the electrical signal; a transmission controller configured to perform control of transmitting the electrical signal to the pixel signal generating unit; an analog-to-digital converter configured to convert the pixel signal into a digital signal; as well as a potential selection unit configured to switch a low potential side reference potential of the photoelectric conversion unit, When the detector detects that the change exceeds the predetermined threshold, the analog-to-digital converter converts the pixel signal into the digital signal, and The potential selection unit selects a first reference potential within a time period when the detector detects whether the change amount exceeds the predetermined threshold, and selects a second reference potential whose potential level is higher than that of the first reference potential within a time period when the analog-to-digital converter converts the pixel signal into the digital signal.

10. The imaging device according to claim 9, wherein The first reference potential is a negative potential, and The second reference potential is ground potential.

11. The imaging device according to claim 9, wherein The low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, the low potential side reference potential of the analog-to-digital converter and the shutdown potential of the transmission controller include two or more potentials with different potential levels.

12. The imaging device according to claim 9, wherein The low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generating unit, and the low potential side reference potential of the analog-to-digital converter are the ground potential, and The off potential of the transmission controller is a negative potential. 13 . The imaging device according to claim 9 , comprising a potential generating unit configured to generate at least one of the first reference potential and the second reference potential.

14. The imaging device according to claim 9, wherein At least the detector is arranged on a second substrate stacked on the first substrate on which the photoelectric conversion unit is arranged.

15. The imaging device according to claim 9, wherein A back gate of a transistor in the transmission controller is set to a potential of the same potential level as the low potential side reference potential of the photoelectric conversion unit.

16. An electronic device comprising: an imaging device configured to output captured image data; and a processor configured to perform predetermined signal processing on the image data; Wherein, the imaging device comprises: a photoelectric conversion unit including a plurality of photoelectric conversion elements, each of the plurality of photoelectric conversion elements performing photoelectric conversion on incident light to generate an electrical signal; a detector configured to output a detection signal indicating whether a change amount of an electrical signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value; a pixel signal generating unit configured to generate a pixel signal based on the electrical signal; a transmission controller configured to perform control of transmitting the electrical signal to the pixel signal generating unit; and an analog-to-digital converter configured to convert the pixel signal into a digital signal, and wherein the low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the detector, the low potential side reference potential of the pixel signal generation unit, the low potential side reference potential of the analog-to-digital converter, and the off potential of the transmission controller include three or more potentials having different potential levels, The low potential side reference potential of the photoelectric conversion unit, the low potential side reference potential of the pixel signal generation unit, and the low potential side reference potential of the analog-to-digital converter are equal.

17. An imaging method comprising: a step of photoelectrically converting incident light using a plurality of photoelectric conversion elements to generate an electrical signal; a step of outputting a detection signal indicating whether a change amount of an electric signal of each of the plurality of photoelectric conversion elements exceeds a predetermined threshold value; a step of transmitting the electrical signal; a step of generating a pixel signal based on the transmitted electrical signal; as well as The step of converting the pixel signal into a digital signal; wherein the low potential side reference potential during the photoelectric conversion, the low potential side reference potential when outputting the detection signal, the low potential side reference potential when generating the pixel signal, the low potential side reference potential when converting the pixel signal into a digital signal, and the off potential when transmitting the electrical signal include three or more potentials having different potential levels, and Using these potentials, the steps of generating an electric signal, outputting a detection signal, transmitting the electric signal, generating a pixel signal, and converting the detection signal into a digital signal are performed. The low potential side reference potential during the photoelectric conversion, the low potential side reference potential during the generation of the pixel signal, and the low potential side reference potential during the conversion of the pixel signal into a digital signal are equal.

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