Light detection device and light detection system

Abstract

A light detection device according to an embodiment of the present disclosure includes a light receiving element capable of receiving light and outputting a current, a control circuit capable of outputting a first signal and a second signal, a connection circuit provided between the light receiving element and a first potential line and controlled by the first signal, and a detection circuit capable of outputting a third signal based on the current from the light receiving element according to the second signal.

Description

Technical Field

[0001] This disclosure relates to optical detection devices and optical detection systems. Background Technology

[0002] A photoelectric conversion device is proposed, which is provided with multiple pixels, each including an avalanche diode (APD) (Patent Document 1).

[0003] Reference List

[0004] Patent documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-106660 Summary of the Invention

[0006] Improvements in the performance of devices for detecting light are desired.

[0007] The goal is to provide a light detection device with excellent performance.

[0008] The light detection apparatus of this disclosure includes: a light receiving element configured to receive light and output current; a control circuit configured to output a first signal and a second signal; a coupling circuit disposed between the light receiving element and a first potential line and controlled by the first signal; and a detection circuit configured to output a third signal based on the current of the light receiving element in response to the second signal.

[0009] The light detection system according to embodiments of this disclosure includes: a light source configured to emit light onto an object; and a light detection device for receiving light from the object. The light detection device includes: a light receiving element configured to receive light and output current; a control circuit configured to output a first signal and a second signal; a coupling circuit disposed between the light receiving element and a first potential line and controlled by the first signal; and a detection circuit configured to output a third signal based on the current of the light receiving element in response to the second signal. Attached Figure Description

[0010] Figure 1 This is a diagram illustrating an embodiment of a schematic configuration of a light detection system according to an embodiment of the present disclosure.

[0011] Figure 2 This is a diagram illustrating an embodiment of the pixel configuration of a light detection device according to an embodiment of the present disclosure.

[0012] Figure 3 This is a timing diagram illustrating an operational embodiment of a light detection system according to an embodiment of the present disclosure.

[0013] Figure 4This is a diagram illustrating another configuration embodiment of the pixels of the light detection device according to an embodiment of the present disclosure.

[0014] Figure 5 This is a timing diagram illustrating an operational embodiment of a light detection system according to an embodiment of the present disclosure.

[0015] Figure 6 This is a diagram illustrating an embodiment of the pixel configuration of the light detection device according to a variation of Example 1 of this disclosure.

[0016] Figure 7 This is a diagram illustrating another configuration embodiment of the pixels of the light detection device according to a variation of Example 1 of this disclosure.

[0017] Figure 8 This is a diagram illustrating a configuration embodiment of the light detection device according to a variation of this disclosure, Example 2.

[0018] Figure 9 This is a diagram illustrating a configuration embodiment of the light detection device according to a variation of this disclosure, Example 2.

[0019] Figure 10A This is a diagram illustrating another configuration embodiment of the light detection device according to Variation 2 of this disclosure.

[0020] Figure 10B This is a diagram illustrating another configuration embodiment of the light detection device according to Variation 2 of this disclosure; Figure 11 This is a diagram illustrating a configuration embodiment of the light detection device according to Variation 3 of this disclosure.

[0021] Figure 12 This is a diagram illustrating another configuration embodiment of the light detection device according to Variation 3 of this disclosure.

[0022] Figure 13 This is a diagram illustrating a configuration embodiment of the light detection device according to Variation 4 of this disclosure.

[0023] Figure 14 This is a diagram illustrating a configuration embodiment of the light detection device according to Variation 5 of this disclosure.

[0024] Figure 15 This is a timing diagram showing an operational embodiment of the light detection device according to Modification 5 of this disclosure.

[0025] Figure 16A This is a diagram illustrating an embodiment of the arrangement of pixels in a light detection device according to a variation of 6 of this disclosure.

[0026] Figure 16BThis is a diagram illustrating an embodiment of the arrangement of pixels in a light detection device according to a variation of 6 of this disclosure.

[0027] Figure 16C This is a diagram illustrating an embodiment of the arrangement of pixels in a light detection device according to a variation of 6 of this disclosure.

[0028] Figure 16D This is a diagram illustrating an embodiment of the arrangement of pixels in a light detection device according to a variation of 6 of this disclosure.

[0029] Figure 17 This is a diagram illustrating an embodiment of the configuration of the light detection device according to Variation 7 of this disclosure.

[0030] Figure 18A This is a diagram illustrating an embodiment of the configuration of the light detection device according to Variation 7 of this disclosure.

[0031] Figure 18B This is a diagram illustrating an embodiment of the configuration of the light detection device according to Variation 7 of this disclosure.

[0032] Figure 19A This is a diagram illustrating another configuration embodiment of the light detection device according to Variation 7 of this disclosure.

[0033] Figure 19B This is a diagram illustrating yet another configuration embodiment of the light detection device according to Variation 7 of this disclosure.

[0034] Figure 19C This is a diagram illustrating yet another configuration embodiment of the light detection device according to Variation 7 of this disclosure.

[0035] Figure 19D This is a diagram illustrating yet another configuration embodiment of the light detection device according to Variation 7 of this disclosure.

[0036] Figure 20 This is a diagram illustrating an embodiment of the pixel configuration of the light detection device according to Variation 8 of this disclosure.

[0037] Figure 21 This is a block diagram illustrating an embodiment of a schematic configuration of a vehicle control system.

[0038] Figure 22 This is a diagram illustrating an embodiment of the installation location of the vehicle exterior information detection unit and the imaging unit. Detailed Implementation

[0039] With reference to the accompanying drawings, embodiments of the present disclosure will be described in detail below. It should be noted that the description is given in the following order.

[0040] 1. Implementation Method

[0041] 2. Variations

[0042] 3. Examples of Use

[0043] 4. Practical Application Examples

[0044] <1. Implementation Method>

[0045] Figure 1 This is a schematic diagram illustrating an embodiment of a light detection system according to an embodiment of the present disclosure. The light detection system 200 includes a light detection device 1, a light source controller 210, and a light source 220. The light detection device 1 is a device configured to detect incident light. The light detection device 1 includes a plurality of pixels P, each pixel P including a light receiving element, and is configured to receive incident light and generate a signal.

[0046] The light-receiving element of pixel P in the light detection device 1 is, for example, an avalanche photodiode (APD), and is configured to receive light and output current. Each light-receiving element (light receiver) of pixel P can be configured to generate a signal in response to the reception of photons. For example, the light detection device 1 receives light that has passed through an optical system (not shown) including an optical lens and generates a signal.

[0047] The light detection device 1 includes, for example, a semiconductor substrate (e.g., a silicon substrate) on which a plurality of pixels P are disposed. As an embodiment, the light detection device 1 has a region (pixel section 100) in which the plurality of pixels P are arranged in a matrix in two dimensions. The pixel section 100 of the light detection device 1 is a pixel array of the plurality of arranged pixels P.

[0048] Each pixel P's light-receiving element may include a single-photon avalanche diode (SPAD). The light detection device 1 receives incident light from the object being measured via an optical system including optical lenses. The light-receiving element can receive light (such as infrared or visible light) from the object being measured, generate an electric charge through photoelectric conversion, and produce a photocurrent.

[0049] The optical detection device 1 can be configured as a range sensor, image sensor, etc. The optical detection device 1 is configured to perform distance measurement, and is configured to perform distance measurement, for example, using a time-of-flight (TOF) method. As an example, the optical detection device 1 is used as a range sensor capable of performing distance measurement using the TOF method.

[0050] The light source 220 is configured to generate light (optical signal). The light source 220 includes, for example, one or more light-emitting elements and is configured to emit light toward the object being measured. The light-emitting elements are, for example, laser diodes (LDs), light-emitting diodes (LEDs), etc., and can output light (such as infrared light or visible light) to the outside.

[0051] As an example, the light source 220 (light source unit) can generate laser light and output the laser light to the outside. The light source 220 may include a semiconductor laser device such as a vertical cavity surface emitting laser (VCSEL).

[0052] The light source controller 210 is configured to control the light source 220. The light source controller 210 is a driver (driving circuit) for driving the light source 220. As an example, the light source controller 210 includes multiple circuits such as a digital-to-analog converter (DAC), amplifier circuitry, etc., and can perform control over the operation of the light source 220. For example, the light source controller 210 is configured to control the current and voltage to the light-emitting element of the light source 220.

[0053] The light source controller 210 can provide current and voltage to the light source 220 for driving the light-emitting element of the light source 220, and control the light emission of the light source 220 (e.g., timing of light emission, duration of light emission, etc.). The light source controller 210 can be referred to as a light source driver configured to drive the light source 220 (the light-emitting element). It should be noted that all or part of the light source 220 and the light source controller 210 can be configured as a whole as a light source device (light source unit).

[0054] The light detection system 200 can cause the light source 220 to emit light (e.g., laser) toward the object being measured and receive the light reflected from the object. In the light detection device 1, for example, the reflected light (return light) reflected by the object being measured enters the pixel unit 100, and an electrical signal in response to the reception of the reflected light is detected. The electrical signal generated by receiving the reflected light from the object being measured becomes a signal corresponding to the distance to the object being measured.

[0055] The light detection system 200, including the light detection device 1, can perform light transmission and reception to measure the distance to a measurement object. As an example, the light detection device 1 is configured to detect the distance to the object (the measurement object) at each pixel P and generate image data (distance image data) regarding the distance to the object. For example, the light detection device 1 can generate a depth map.

[0056] It should be noted that the optical detection device 1 can also be used as a sensor configured to detect events, such as an event-driven sensor (called an event vision sensor (EVS), event-driven sensor (EDS), dynamic vision sensor (DVS), etc.). The optical detection device 1 and the optical detection system 200 can be applied to various electronic devices.

[0057] As an example, the light detection device 1 includes (as in...) Figure 1(In the embodiment shown) Pixel unit 100, pixel controller 110, signal processor 112, and controller 113. It should be noted that the light detection device 1 may include a light source controller 210. Furthermore, the light source 220 may be installed in the light detection device 1 or may be located outside the light detection device 1.

[0058] Pixel controller 110 is configured to control each pixel P of pixel unit 100. Pixel controller 110 is a control circuit and includes multiple circuits, such as buffers, shift registers, and address decoders. Pixel controller 110 (control circuit) includes, for example, a pulse generation circuit. Pixel controller 110 generates signals for controlling pixel P and outputs these signals to each pixel P of pixel unit 100. Pixel controller 110 is controlled by controller 113 and performs control of pixels P of pixel unit 100.

[0059] For example, pixel controller 110 generates signals for controlling pixels P, such as signals for controlling the readout circuitry of pixel P, and provides these signals to each pixel P. Pixel controller 110 can perform control of reading pixel signals from each pixel P. Pixel controller 110 can be described as being configured to drive a pixel driver (pixel driver circuitry) for each pixel P. It should be noted that pixel controller 110 and controller 113 can be collectively referred to as pixel controllers.

[0060] The controller 113 is configured to control each unit of the light detection device 1. The controller 113 can receive data such as clock signals and command operation modes from external sources, and output data such as internal information of the light detection device 1. The controller 113 is a control circuit and includes, for example, a timing generator configured to generate various timing signals.

[0061] The controller 113 performs control of the drive pixel controller 110, signal processor 112, etc., based on various timing signals (pulse signals, clock signals, etc.) generated by the timing generator. The controller 113 may include circuitry such as phase-locked loops (PLLs) and digital-to-analog converters (DACs).

[0062] Furthermore, the controller 113 is used to provide signals to the light source controller 210 to control the operation of the light source controller 210. The controller 113 can be configured to control the processing of pixel signals generated by pixel P in the pixel unit 100, the timing of light emission from the light source 220, etc.

[0063] Signal processor 112 is a signal processing circuit and is configured to perform signal processing. Signal processor 112 includes circuitry that performs various signal processing on signals output from each pixel P. Signal processor 112 includes arithmetic circuitry, memory circuitry, etc., and is capable of performing various signal processing operations, such as noise reduction processing, time-to-digital (TD) conversion processing, and counting (accumulation) processing.

[0064] Signal processor 112 is configured to acquire the signal of each pixel P and generate and output a signal relating to the distance to the object being measured. For example, signal processor 112 may perform various signal processing operations on the signal of each pixel P and generate and output distance image data representing the distance to the object being measured. It should be noted that signal processor 112 and controller 113 may be configured as a single unit. Signal processor 112 and controller 113 may include a processor and a memory.

[0065] For example, as in Figure 1 In the illustrated embodiment, the signal processor 112 includes a computing unit 120 and a storage unit 130. The storage unit 130 is a storage circuit and includes multiple memories (storage cells). The storage unit 130 is, for example, a frame memory, and stores (records) the pixel signal of each pixel P on a frame-by-frame basis. The computing unit 120 can control the writing of data to and reading of data from the storage unit 130.

[0066] The calculation unit 120 is used to acquire the pixel signal of pixel P and perform signal processing on the pixel signal. For example, the calculation unit 120 is configured to generate a signal (distance signal) about the distance to the measured object based on the pixel signal. In the light detection system 200, for example, the emission and cessation of light from the light source 220 are repeatedly performed, and the detection of reflected light (return light) from pixel P is repeatedly performed. The calculation unit 120 can analyze the pixel signals sequentially output from each pixel P through multiple distance measurements, thereby generating and outputting image data (distance image data) including the distance signal through each pixel P.

[0067] The calculation unit 120 includes, for example, a histogram generator 125 and is configured to generate histograms of pixel signals. As an embodiment, the histogram generator 125 (histogram generation circuit) is configured to generate histograms of signal values ​​of pixel signals (i.e., counts of the light turnaround time for each pixel P).

[0068] Histogram generator 125 can generate histogram data showing the correspondence between count values ​​based on light turnaround time and the frequency (quantity) of the count values, and stores this data, for example, in storage unit 130. As an example, histogram generator 125 divides the count values ​​into predetermined intervals (ranges), i.e., into categories (bins), and generates histogram data indicating the distribution of the count values ​​based on the distance to the object being measured.

[0069] The calculation unit 120 is configured to calculate the distance to the object being measured based on the peak value (maximum value) in the histogram of the pixel signal values. For example, based on the pixel signal value (count value) of the peak value in the histogram indicating the frequency of the pixel signal, the calculation unit 120 calculates (estimates) the difference between the start time of light emission and the arrival time of the returning light, i.e., the turnaround time (time of flight) of the light.

[0070] The calculation unit 120 is configured to calculate, for example, the distance between the light detection device 1 and the object being measured using the calculated turnaround time. The calculation unit 120 calculates the distance to the object for each pixel P and generates a distance signal regarding the distance to the object. The distance to the object is found based on the time taken for light emitted from the light source 220 and reflected by the object to reach the light detection device 1. The signal processor 112 enables the calculation unit 120 to generate distance image data including the distance signal for each pixel P and outputs the distance image data to the outside of the light detection device 1.

[0071] It should be noted that the pixel unit 100, pixel controller 110, signal processor 112, controller 113, etc., described above can be disposed in one substrate, or can be disposed separately in multiple substrates. The light detection device 1 may have, for example, a structure in which multiple semiconductor layers are stacked on top of each other (stacked structure). It should be noted that all or some of the pixel controller 110, signal processor 112, and controller 113 can be configured as a whole.

[0072] Figure 2 This is a diagram illustrating an embodiment of the pixel configuration of a light detection device according to an implementation. A pixel P of the light detection device 1 includes a light receiving element 10 and a readout circuit 20. The light receiving element 10 is configured to receive light and generate a signal. For example, a readout circuit 20 is provided for each light receiving element 10.

[0073] The light receiving element 10 is, for example, a single-photon avalanche diode (SPAD) and has a multiplication region (multiplier) that enables avalanche multiplication. The light receiving element 10 can convert incident photons into electrical charges and output a signal S1 as an electrical signal based on the incident photons. It should be noted that the light receiving element 10 can be described as a photoelectric conversion element (photoelectric converter) configured to convert photoelectric signals into light.

[0074] The readout circuit 20 is configured to output a current signal based on the photocurrent of the photoreceiving element 10. The readout circuit 20 includes circuitry for reading a signal based on the photocurrent flowing through the photoreceiving element 10, such as a coupling circuit 30, an output circuit 40, and a detection circuit 50.

[0075] A coupling circuit 30 is disposed between the light-receiving element 10 and the potential line L1, and is configured to recharge the light-receiving element 10. The potential line L1 is a wiring supplied with a predetermined potential (voltage). Figure 2 In the embodiment shown, the potential line L1 is a power line supplied with a power supply voltage VDD. The coupling circuit 30 is electrically coupled to the power line supplied with the power supply voltage VDD and can supply current and voltage to the light receiving element 10.

[0076] The coupling circuit 30 is controlled by the signal CK1 and configured to perform recharging of the light receiving element 10. The pixel controller 110 can output the signal CK1 to control the coupling circuit 30 and control the recharging of the light receiving element 10. For example, the pixel controller 110 can provide the signal CK1 as a pulse signal to the coupling circuit 30 and control the timing of the recharging of the light receiving element 10.

[0077] The coupling circuit 30 includes, for example, a switch and is electrically coupled in series between the light-receiving element 10 and the potential line L1. As an embodiment, the coupling circuit 30 is configured to electrically couple or decouple the potential line L1 from the light-receiving element 10 based on a signal CK1 input from the pixel controller 110. The coupling circuit 30 may be referred to as a control circuit for controlling recharging.

[0078] The coupling circuit 30 includes, for example, a switch that electrically couples or decouples the power supply line from the light receiving element 10. For example, the coupling circuit 30 includes a P-type transistor (e.g., a PMOS transistor). For example, in the transistor of the coupling circuit 30, one source and the other drain are electrically coupled to the power supply line provided with the power supply voltage VDD, and the other is electrically coupled to the light receiving element 10.

[0079] For example, the pixel controller 110 repeatedly outputs the signal CK1 as a pulse signal to the coupling circuit 30, and puts the coupling circuit 30 into a conducting state at predetermined time intervals. The pixel controller 110 can perform periodic recharging (i.e., timed recharging) of the light receiving element 10 by controlling the coupling circuit 30.

[0080] For example, the optical receiving element 10 is electrically coupled to a power supply line, electrodes, etc., that allows a predetermined voltage to be supplied. Figure 2 In the embodiment shown, the cathode, which is one of the electrodes of the light receiving element 10, is electrically coupled to the coupling circuit 30. The anode, which is the other electrode of the light receiving element 10, is coupled to the reference potential line side.

[0081] The anode of the light-receiving element 10 is electrically connected to, for example, wiring, electrodes, etc., which are supplied with a relatively low power supply voltage. Figure 2 In the embodiment shown, a voltage VSP is supplied to the anode of the light-receiving element 10 from a power supply unit (voltage source) configured to provide voltage (current) via a potential line L2, which serves as a power supply line. The voltage VSP is, for example, a negative voltage.

[0082] Due to the voltage provided through coupling circuit 30 and the voltage VSP provided through potential line L2, a voltage with a potential difference greater than the breakdown voltage of light receiving element 10 can be applied between the cathode and anode of light receiving element 10. That is, the potential difference between the two ends of light receiving element 10 can be set to a potential difference greater than the breakdown voltage.

[0083] When a reverse bias voltage greater than the breakdown voltage is supplied, the photoreceiving element 10 enters an adaptation state to operate in Geiger mode. In Geiger mode, the photoreceiving element 10 may experience avalanche multiplication in response to the incident photon, and a pulsed current may be generated. In pixel P, a signal S1 based on the photocurrent flowing through the photoreceiving element 10 due to the incident photon is output to the output circuit 40.

[0084] After avalanche multiplication has occurred and the potential difference between the electrodes of the light receiver 10 has become less than the breakdown voltage, the coupling circuit 30 enters the conducting state, which allows the light receiver 10 to re-enter the mating state for operation in Geiger mode. The coupling circuit 30 can recharge the charge to the light receiver 10 and recharge the voltage of the light receiver 10.

[0085] Output circuit 40 is configured to generate signal P1 based on signal S1 generated by light receiving element 10. Output circuit 40 can output signal P1, which is a voltage signal based on the current of light receiving element 10. For example, output circuit 40 includes an inverter. Output circuit 40 includes, for example, input unit 41 and output unit 42, and can output an inverted signal of the input signal.

[0086] For example, the input unit 41 of the output circuit 40 is electrically coupled to the cathode of the photoreceiving element 10 and the coupling circuit 30. Figure 2 In the illustrated embodiment, the input unit 41 of the output circuit 40 is electrically coupled to node N1, which couples the light receiving element 10 and the coupling circuit 30. The output unit 42 of the output circuit 40 is electrically coupled to the detection circuit 50. It should be noted that the output circuit 40 may include circuits such as AND circuits, NAND circuits, OR circuits, or NOR circuits.

[0087] A signal S1 from the photodetector 10 is input to the output circuit 40. The signal level of signal S1 (i.e., the voltage (potential) of signal S1) varies depending on the current flowing through the photodetector 10. For example, when the voltage of signal S1 is higher than a threshold, the output circuit 40 outputs a low-level signal P1. Conversely, when the voltage of signal S1 is lower than the threshold, the output circuit 40 outputs a high-level signal P1. The output circuit 40 can output signal P1 to the detection circuit 50 based on the voltage of signal S1.

[0088] The detection circuit 50 includes, for example, logic circuitry such as a flip-flop. A signal CK2 is input from the pixel controller 110 to the detection circuit 50. The detection circuit 50 is configured to output a current signal P2 based on the current of the light receiving element 10 in response to the signal CK2. For example, the detection circuit 50 is configured to sample and output a data signal synchronized with the signal CK2 as a pulse signal.

[0089] exist Figure 2 In the embodiment shown, signal P1 is input from output circuit 40 to detection circuit 50. For example, in response to signal CK2 as a clock signal (or enable signal), detection circuit 50 performs sampling of signal P1 as a data signal and outputs signal P2 based on signal P1. Synchronized with signal CK2, detection circuit 50 can acquire and hold signal P1 and output signal P2 according to signal P1.

[0090] Pixel controller 110 can provide signals CK1 and CK2 to pixel P to control the operation of pixel P. For example, pixel controller 110 is configured to change the timing to output signals CK1 and CK2. Pixel controller 110 can repeatedly output signal CK1 as a pulse signal to coupling circuit 30 and perform recharging of photoreceiving element 10 at predetermined time intervals.

[0091] For example, pixel controller 110 adjusts the timing to output signal CK2 (which is a pulse signal), thereby setting the timing for detection circuit 50 to generate and output signal P2. Pixel controller 110 is configured to change the time period from the timing of transition to signal CK1 to the timing of transition to signal CK2. During the time period from the timing of transition to signal CK1 (i.e., recharge timing) to the timing of transition to signal CK2, detection circuit 50 can output signal P2 based on signal P1.

[0092] In pixel P of the light detection device 1, for example, the time period from the transition timing of signal CK1 (e.g., the falling edge of signal CK1) to the transition timing of signal CK2 (e.g., the rising edge of signal CK2) is the detection time period in pixel P, that is, the time period of light detection performed by the light receiving element 10. By controlling signals CK1 and CK2, the detection time period (i.e., binary bits) can be changed.

[0093] Figure 3 This is a timing diagram illustrating an operational embodiment of the optical detection system according to an implementation. Figure 3 The timing diagram shows signals CK1, CK2, and the detection period (bin) on the horizontal axis. Additionally, examples of emitted light and reflected light from the object being measured are schematically illustrated. Figure 3 When signal CK1 is set to low level, coupling circuit 30 enters the conduction state and performs recharging of optical receiving element 10.

[0094] In the optical detection device 1, such as in Figure 3 In the example shown, CK1, as a pulse signal, is periodically input from pixel controller 110 to coupling circuit 30, and periodic recharging is performed. In response to the rising edge of signal CK2, detection circuit 50 generates and outputs signal P2 indicating whether light reception is present or absent during the detection period. Pixel controller 110 can change the length (bin width) of the detection period by adjusting the rising timing of signal CK2.

[0095] As an example, the pixel controller 110 can be set to a short detection period t. shortbin and long detection period t 1ongbin Detection period t shortbin This refers to a detection period, for example, used for measurements at short distances, and is suitable for measurements taken when the reflected light arrives early (i.e., at a relatively short distance from the object being measured). Detection period t 1ongbin For example, it is a detection period for measuring at intermediate to long distances, and it is a detection period suitable for measuring when the arrival time of reflected light is late (i.e., when the distance to the object being measured is relatively long).

[0096] Pixel controller 110 sets, for example, the detection period t by adjusting the rise time of signal CK2. shortbin and during the detection period t shortbin The subsequent detection period t 1ongbin .exist Figure 3 In the embodiment shown, during the detection period t shortbin Then set multiple detection time periods t 1ongbin It should be noted that, if in Figure 3 In the embodiment indicated by the dashed line, the pixel controller 110 is able to appropriately adjust the detection time period t. shortbin The length.

[0097] The pixel P of the light detection device 1 sequentially outputs, for example, signals P2a and P2b, where signal P2a is generated during the detection period t. shortbinThe signal P2 indicates whether the reflected light is received or not, and the signal P2b is received during the detection period t. longbin The signal P2 indicates whether the reflected light is received or not. The signal processor 112 can acquire signals P2a and P2b output from each pixel P and calculate the distance to the object being measured.

[0098] The signal processor 112 uses signals (e.g., signals P2a and P2b) output from each pixel P for each detection period to determine whether the distance to the object being measured is short or medium to long. Furthermore, based on the determined results, the signal processor 112 can find the distance to the object by calculating the arrival timing of the reflected light through centroid calculation or similar methods.

[0099] Figure 4 This is a diagram illustrating another configuration embodiment of the pixels of the light detection device according to an implementation method. (As shown in...) Figure 4 In the embodiment shown, the readout circuit 20 for pixel P may include an AND circuit 55 and a counter 60. A signal P2 from the detection circuit 50 and a signal CK2 from the pixel controller 110 are input to the AND circuit 55.

[0100] Counter 60 is configured to count signals based on the current of the optical receiving element 10. Figure 4 In the illustrated embodiment, signal Pout, which is the output signal of AND circuit 55, is input to counter 60. Based on signal Pout, counter 60 counts signal P2 during the period when signal CK2 is high. Counter 60 can count the number of pulses of signal Pout based on the current of optical receiving element 10 and output a signal indicating the count value.

[0101] Figure 5 This is a timing diagram illustrating an operational embodiment of the optical detection system according to an implementation. Figure 5 In this diagram, signals S1, CK1, P1, CK2, P2, Pout, and the count value of counter 60 are shown on the same time axis. It should be noted that... Figure 5 In the diagram, the timing of photons incident on the light receiving element 10 is schematically shown by the dashed arrow.

[0102] In the optical detection device 1, such as in Figure 5 In the embodiment shown, signal CK1 is periodically switched from high to low by pixel controller 110, and a recharge period is set. The period from the falling timing of signal CK1 to the rising timing of signal CK2 is the detection period.

[0103] In response to the reception of photons in the light-receiving element 10, the detection circuit 50 outputs signal P2 to the counter 60 as signal Pout via the AND circuit 55. For example, the counter 60 can count the number of pulses of signal Pout to obtain a count value, and output a digital signal indicating the count value to the signal processor 112 (see...). Figure 1 ).

[0104] As described above, the pixel controller 110 of the light detection device 1 is configured to control the signal CK1 provided to the coupling circuit 30 and perform periodic recharging of the light receiving element 10. Furthermore, the pixel controller 110 is configured to control the signal CK2 provided to the detection circuit 50 and change the detection period. In this embodiment, dead time can be disregarded, which allows for the accurate generation of a histogram indicating the count value for each detection period (bin).

[0105] When performing short-distance measurements, for example, the pixel controller 110 sets the bin width (the length of the detection period) to a short value, thereby appropriately adjusting the distance measurement range and improving the accuracy of the distance measurement. Furthermore, when performing measurements from intermediate to long distances, for example, the pixel controller 110 sets the bin width to a long value, thereby expanding the distance measurement range. This allows for accurate short-distance measurements while ensuring a good distance measurement range on the long-distance side.

[0106] [Functions and Effects]

[0107] The light detection apparatus (light detection apparatus 1) according to this embodiment includes: a light receiving element (light receiving element 10) configured to receive light and output current; a control circuit (pixel controller 110) configured to output a first signal and a second signal (e.g., signal CK1 and signal CK2); a coupling circuit (coupling circuit 30) disposed between the light receiving element and a first potential line (potential line L1) and controlled by the first signal; and a detection circuit (detection circuit 50) configured to output a third signal (signal P2) based on the current of the light receiving element in response to the second signal.

[0108] The light detection apparatus 1 according to this embodiment includes: a pixel controller 110 configured to output signals CK1 and CK2; a coupling circuit 30 controlled by signal CK1; and a detection circuit 50 configured to output signal P2 in response to signal CK2. In this embodiment, the recharging and detection periods can be controlled, thus enabling a light detection apparatus with excellent performance.

[0109] Subsequently, variations of this disclosure are described. In the following, components similar to those in the above embodiments are assigned the same reference numerals, and their descriptions are omitted accordingly.

[0110] <2. Variations>

[0111] (2-1. Variation Example 1)

[0112] Figure 6 This is a diagram illustrating an embodiment of the pixel configuration of the light detection apparatus according to a variation of 1 of the present disclosure. The pixels P of the light detection apparatus 1 include, as shown in the diagram... Figure 6 The transistor Tr1 is shown. Furthermore, the photodetector 1 may include a voltage generator 140. Transistor Tr1 is a voltage-limiting transistor and is referred to as a clamping transistor. It should be noted that transistor Tr1 can be configured as part of the readout circuit 20.

[0113] Voltage generator 140 is a voltage generation circuit configured to generate a voltage and is configured to output a predetermined voltage (potential) to transistor Tr1. For example, voltage generator 140 may be provided shared by multiple pixels P. It should be noted that voltage generator 140 may be disposed separately from pixel controller 110, or it may be disposed within pixel controller 110.

[0114] For example, voltage generator 140 is configured to generate a bias voltage and provide the generated bias voltage to the gate of transistor Tr1. Voltage generator 140 includes, for example, a boost converter, a buck converter, etc. Voltage generator 140 may be referred to as a bias generation circuit (bias generator) configured to generate a bias voltage.

[0115] Transistor Tr1 is electrically coupled between the light-receiving element 10 and the coupling circuit 30. As an example, transistor Tr1 includes a PMOS transistor and is series-coupled between node N1, which is coupled to the coupling circuit 30, and the light-receiving element 10. Transistor Tr1 includes, for example, a thick gate insulating film and is configured as a high-voltage transistor.

[0116] One of the source and drain of transistor Tr1, for example, the source of transistor Tr1 is electrically coupled to coupling circuit 30 and output circuit 40. The other of the source and drain of transistor Tr1, for example, the drain of transistor Tr1 is electrically coupled to photoreceiving element 10. For example, a constant bias voltage is provided to the gate of transistor Tr1 by voltage generator 140.

[0117] In this modified example, transistor Tr1 is disposed between the light receiving element 10 and the coupling circuit 30, which allows a low-voltage transistor to be used as the transistor coupled to the source side of transistor Tr1. For example, the transistors included in the coupling circuit 30, the transistors included in the output circuit 40, and the transistors included in the detection circuit 50 can each be configured with a transistor having a thin gate insulating film.

[0118] This can reduce the gate capacitance of the transistor input to signal CK1 and the gate capacitance of the transistor input to signal CK2, and can also make the amplitude (voltage amplitude) of signals CK1 and CK2 smaller. Therefore, the signal speed of signals CK1 and CK2 can be increased, which enables high-speed operation.

[0119] Figure 7 This is a diagram illustrating another configuration embodiment of the pixels of the light detection device according to Modification 1. The light detection device 1 may include a power supply unit 145, such as... Figure 7 As shown in the diagram, power supply unit 145 is configured to supply a predetermined voltage. In one embodiment, power supply unit 145 is electrically coupled to the drain of transistor Tr1 and the photoreceiving element 10.

[0120] exist Figure 7 In the embodiment shown, the power supply unit 145 is electrically coupled to the potential line L3 (power line) to which the supplied voltage VRL is located, and is configured to supply the voltage VRL to the drain side of the transistor Tr1, i.e., the cathode side of the photoreceiving element 10. The voltage VRL is, for example, the voltage value between the power supply voltage VDD and the voltage VSP.

[0121] For example, when the cathode voltage of the light receiver 10 drops in response to photons incident on the light receiver 10, the power supply unit 145 supplies voltage VRL to the cathode of the light receiver 10. In this case, the potential difference between the two ends of the light receiver 10 becomes less than the breakdown voltage, and the light receiver 10 can be placed in a state where avalanche multiplication does not occur.

[0122] For example, by supplying voltage VRL to the light-receiving element 10, avalanche multiplication can be prevented from recurring during the detection period, and power consumption can be suppressed. This further saves power compared to the case where current flows from the potential line L1, which is supplied with power supply voltage VDD, to the anode side of the light-receiving element 10, which is supplied with voltage VSP.

[0123] (2-2. Variation Example 2)

[0124] Figure 8 and Figure 9 This is a diagram illustrating an embodiment of the configuration of the light detection device according to Modified Example 2. The pixel P of the light detection device 1 may have... Figure 8 The configuration shown is illustrated. The light detection device 1 includes, as shown... Figure 9 The processor 70 is shown. The readout circuit 20 of pixel P is configured to output the signal Pout to the processor 70.

[0125] Processor 70 (processing circuitry) includes, for example, multiple counters 60 (in... Figure 9The processor 70 includes counters 60a to 60n and a selector 65. For example, a processor 70 is provided for each pixel P or multiple pixels P. As an embodiment, the processor 70 includes multiple counters 60 corresponding to the number of settings (detection periods) of the bins.

[0126] Selector 65 is configured to output the signal Pout from pixel P to a selected counter 60 among a plurality of counters 60. Selector 65 can be configured to switch the output destination of signal Pout. Selector 65 is selection circuitry, such as including a shift register. As an example, as in... Figure 9 In the embodiment shown, selector 65 includes multiple flip-flops and multiple AND circuits.

[0127] For example, selector 65 outputs signal Pout to the selected counter 60 in response to signal BIN_CLK, which is a clock signal. Signal Pout is input to counter 60 selected by selector 65, and a counting operation is performed in response to signal Pout. Note that all or part of the readout circuit 20 and processor 70 of pixel P can be configured as a single unit. For example, readout circuit 20 may include processor 70.

[0128] Figure 10A This is a diagram illustrating another configuration embodiment of the light detection device according to Modification 2. The light detection device 1 may include an output circuit 66. The output circuit 66 is configured, for example, for a plurality of pixels P, and is configured to output a signal Poutx based on a plurality of signals Pout. The output circuit 66 includes, for example, an OR circuit. The output circuit 66 may be configured to output a signal Poutx obtained by adding the plurality of signals Pout.

[0129] exist Figure 10A In the embodiment shown, output circuit 66 is provided for and electrically coupled to four pixels P. Each signal Pout of the four pixels P is input to output circuit 66. Output circuit 66 can output signal Poutx as a signal where the four signals Pout are combined to processor 70.

[0130] In processor 70, signal Poutx is input to counter 60 selected by selector 65, and counter 60 performs a counting operation in response to signal Poutx. For example, in multiple pixels P (in Figure 10A In the case where any one of the four pixels P has detected light, the count value increases, which can improve the detection probability of reflected light.

[0131] It should be noted that, if in Figure 10B In the example shown, output circuit 66 can be provided in processor 70 (processing circuitry). Figure 10BIn the illustrated embodiment, the processor 70 includes an output circuit 66, a selector 65, a counter 60, etc.

[0132] (2-3. Variation Example 3)

[0133] Figure 11 This is a diagram illustrating an embodiment of the configuration of the light detection apparatus according to Modification 3. The processor 70 can be configured to count the number of pixels that have received light based on a signal Pout from a plurality of pixels P. For example, the processor 70 is configured to count two or more pixels in response to a single pulse signal caused by the signal CLK. As an embodiment, the processor 70 can count multiple values ​​(e.g., "0" to "2") in response to a single pulse.

[0134] Processor 70 includes output circuitry 66, selector 65, and multiple counters 60. Output circuitry 66 includes, for example, shift registers, selectors, AND circuits, EXOR circuits, etc. For example, output circuitry 66 includes shift registers 67a and 67b.

[0135] Shift registers 67a and 67b each include half the number of triggers for a predetermined number of pixels P. The individual signals Pout of the plurality of pixels P, including pixel Pa, are input to shift register 67a, and the individual signals Pout of the plurality of pixels P, including pixel Pb, are input to shift register 67b.

[0136] For example, in response to the signal CLK, which is a clock signal, shift register 67a stores the signal Pout input from each pixel P coupled to shift register 67a. Furthermore, in response to the signal CLK, shift register 67a sequentially outputs the stored signal Pout of each pixel P as the signal SR1.

[0137] For example, in response to the signal CLK, which is a clock signal, shift register 67b stores the signal Pout input from each pixel P coupled to shift register 67b. Furthermore, in response to the signal CLK, shift register 67b sequentially outputs the stored signal Pout of each pixel P as signal SR2.

[0138] Output circuit 66 generates signals c and s based on signal SR1 from shift register 67a and signal SR2 from shift register 67b, and outputs them to selector 65. For example, as in Figure 11 In the embodiment shown, the signal c and signal s indicating the sum of the signal SR1 and signal SR2 can be output by the AND circuit and the EXOR circuit, respectively.

[0139] Selector 65 is configured to output signals c and s, which are input from output circuit 66, as signals c_bin and s_bin to a selected counter 60 among a plurality of counters 60. For example, selector 65 (selection circuit) outputs signals c_bin and s_bin to the selected counter 60 in response to signal BIN_CLK, which is a clock signal.

[0140] In processor 70, signals c_bin and s_bin are input to counter 60 selected by selector 65, and a counting operation is performed in response to signals c_bin and s_bin. For example, when signal c_bin is low (i.e., the value of signal c_bin is "0") and signal s_bin is high (i.e., the value of signal s_bin is "1"), signal CLK is input as signal s_cnt to the flip-flop that holds the value of LSB therein, thereby incrementing by "+1".

[0141] Furthermore, when signal c_bin is high (i.e., the value of signal c_bin is "1") and signal s_bin is low (the value of signal s_bin is "0"), signal CLK is input as signal s_cnt to the flip-flop that holds the value of (LSB+1) therein, thereby performing an increment of "+2".

[0142] In this way, the light detection device 1 according to this modification can add the signals of multiple pixels P and increment the added value. For example, a single pulse signal caused by the signal CLK allows the light detection device 1 to count "0", "1" or "2". In the light detection device 1, the number corresponding to the number of responding pixels (i.e., the number corresponding to the number of pixels that have received light) can be counted, and the S / N ratio can be improved.

[0143] It should be noted that the configuration of the light detection device 1 is not limited to the above embodiment and can be appropriately changed. For example, the light detection device 1 can be configured to add the signals of three or more pixels and count using the summed value. For example, the processor 70 can be configured to use a signal composed of signals of four or more pixels combined to perform increments.

[0144] Figure 12 This is a diagram illustrating another configuration embodiment of the light detection device according to Variation 3. The output circuit 66 includes, for example, shift registers 67a, 67b, 67c, and 67d. Each of shift registers 67a to 67d includes as many flip-flops as one-quarter the number of the predetermined number of pixels P. The processor 70 may include a bit selector 68 (bit selection circuit).

[0145] For example, shift register 67a extracts the signal Pout input from each pixel P coupled to shift register 67a, and sequentially outputs the signal Pout of each pixel P as signal SR1. Furthermore, shift register 67b obtains the signal Pout input from each pixel P connected to it, and sequentially outputs the signal Pout of each pixel P as signal SR2.

[0146] Furthermore, shift register 67c extracts the signal Pout from each pixel P input coupled to shift register 67c, and sequentially outputs the signal Pout of each pixel P as signal SR3. In addition, shift register 67d extracts the signal Pout from each pixel P input coupled to shift register 67d, and sequentially outputs the signal Pout of each pixel P as signal SR4.

[0147] Output circuit 66 generates signals c3, c2, and c1 based on signals SR1 to SR4 from shift registers 67a to 67d, and outputs them to selector 65. Output circuit 66 includes, for example, a 4-input adder and can output signals c3, c2, and c1 indicating the sum of signals SR1 to SR4.

[0148] Selector 65 is configured to output signals c3, c2, and c1 from output circuit 66 as selected counters 60 among a plurality of counters 60 as signals c3_bin, c2_bin, and c1_bin. For example, selector 65 outputs signals c3_bin to c1_bin to the selected counter 60 in response to signal BIN_CLK.

[0149] In processor 70, signals c3_bin to c1_bin are input to counter 60 selected by selector 65, and a counting operation is performed in response to signals c3_bin to c1_bin. Bit selector 68 controls signals sel0, sel1a, sel1b, and sel2 to be supplied to counter 60 based on the signal values ​​of signals c3_bin to c1_bin.

[0150] For example, when signals c3_bin, c2_bin, and c1_bin are low and high, bit selector 68 sets signal sel0 high and signal sel1b high. Furthermore, bit selector 68 sets signals sel1a and sel2 low. In this case, signal CLK is input as signal clk0 to the flip-flop that holds the value of the LSB, thus performing an increment of "+1".

[0151] With signal c3_bin low, signal c2_bin high, and signal c1_bin low, bit selector 68 sets signals sel1a and sel1b high. Additionally, bit selector 68 sets signals sel0 and sel2 low. In this case, signal CLK is input as signal clk1 to the flip-flop holding a value of (LSB+1), thus performing a +2 increment.

[0152] With signal c3_bin low, signal c2_bin high, signal c1_bin high, and signal s_lsb (LSB data) low, bit selector 68 sets signals sel0, sela, and sel1b high. Additionally, bit selector 68 sets signal sel2 low.

[0153] In this configuration, signal CLK is input as signal clk0 to a flip-flop that holds the LSB value. Additionally, signal CLK is input as signal clk1 to a flip-flop that holds the value of (LSB+1). The LSB value is inverted (in this case, +1), and the value of (LSB+1) is incremented by "+1", thus incrementing counter 60 by "+3".

[0154] When signals c3_bin, c2_bin, c1_bin, and s_lsb are all low, bit selector 68 sets signals sel0 and sel2 to high. Conversely, bit selector 68 sets signals sel1a and sel1b to low.

[0155] In this configuration, signal CLK is input as signal clk0 to the flip-flop holding the LSB value. Additionally, signal CLK is input as signal clk2 to the flip-flop holding the value (LSB+2). The LSB value is inverted (in this case, -1), and the value of (LSB+2) is incremented by "+1", thus incrementing counter 60 by "+3".

[0156] Furthermore, when signal c3_bin is high, signal c2_bin is low, and signal c1_bin is low, bit selector 68 sets signal sel2 high and signals sel0 and sel1a low. In this case, signal CLK is input as signal clk2 to the flip-flop holding the value (LSB+2) therein, thereby performing an increment of "+4".

[0157] (2-4. Variation Example 4)

[0158] Figure 13 This diagram illustrates an embodiment of the configuration of the light detection device according to Modification 4. The light detection device 1 has multiple operating modes. For example, as operating modes, the light detection device 1 has a first mode and a second mode. In the first mode, the light detection device 1 performs processing to count the output signals of each pixel P. In the second mode, the light detection device 1 can add the output signals of multiple pixels P and perform processing to count the added signals.

[0159] For example, such as Figure 13 As described above, the optical detection device 1 may include a switching circuit 69 in addition to the output circuit 66 and selector 65 already described. For example, the switching circuit 69 may include multiple selectors (multiplexers). The switching circuit 69 may be configured to switch signal paths.

[0160] For example, selector 65 outputs signal Poutx to a selector within switching circuit 69, which is connected to counter 60 selected by selector 65. As described above, signal Poutx is a signal based on signals Pout of multiple pixels, and is obtained by, for example, adding four signals Pout together.

[0161] For example, the selector of the switching circuit 69 is configured to output either the signal Pout input from pixel P or the signal Pout input from selector 65 to counter 60. Figure 13 In the embodiment shown, the switching circuit 69 can output the signal Pout or the signal Poutx to the counter 60 based on the signal s_mode.

[0162] In the first mode, for example, the signal s_mode is high, so the switching circuit 69 outputs the individual signals Pout of pixel P to separate counters 60. Multiple pixels P (in...) Figure 13 In this setup, the corresponding signals Pout of the four pixels P are counted by separate counters 60. In the light detection device 1, one pixel P is associated with one counter 60, which allows the output signals of all pixels P to be counted.

[0163] In the second mode, for example, the signal s_mode is at a low level, so the switching circuit 69 outputs the signal Poutx to the counter 60 selected by the selector 65. In the light detection device 1, for example, counting can be performed by the counter 60 selected by each detection period (cell), and the count value can be obtained for each detection period.

[0164] (2-5. Variation Example 5)

[0165] Figure 14This is a diagram used to explain an embodiment of the configuration of the light detection device according to Modification 5. As shown in... Figure 14 In the embodiment shown, the light detection device 1 includes switches SW1 and SW2. Switches SW1 and SW2 are provided for each pixel P (or each counter 60). For example, switches SW1 and SW2 are electrically coupled between signal line Ls and counter 60, and signal line Ls is coupled to signal processor 112, which includes computing unit 120 and storage unit 130.

[0166] Each of switches SW1 and SW2 includes, for example, a transistor. Switches SW1 and SW2 are each controlled to be on or off by a signal input from pixel controller 110. Pixel controller 110 can perform the process of reading out a signal indicating the count value held in counter 60 to signal line Ls.

[0167] For example, pixel controller 110 controls switch SW1, causing counter 60 to output a signal indicating the value of the most significant bit (MSB) to calculation unit 120. Alternatively, pixel controller 110 may control switch SW2, causing counter 60 to output a signal indicating the value of the remaining bits other than the MSB to calculation unit 120.

[0168] Figure 15 This is a timing diagram showing an operational embodiment of the light detection device according to Modification 5. Figure 15 In the same timeline, the count value of counter 60, the MSB of the count value, the read MSB, the read all bit data, and the value of the MSB stored in the frame memory are schematically shown. Furthermore, in Figure 15 In the diagram, the timing of reading the MSB from counter 60 is represented by a dashed line.

[0169] As in Figure 15 In the example shown, the pixel controller 110 can read only the MSB value from the counter 60 during the exposure period and store the MSB value in the storage unit 130 (frame memory), and read "Ndata", which is the value of all bits of the counter 60 after the exposure period. For example, the counter 60 is configured to not be reset if its count value reaches "Nmax (maximum value)" and to start counting again from "0". As an example, the number of times the count value of the counter 60 reaches Nmax is stored in the storage unit 130.

[0170] For example, the pixel controller 110 can base its operation on the fact that the count value has reached Nmax (in Figure 15 In the embodiment shown, the total value is calculated by the number of times n=3, “Ndata” as the value of all bits, and the following equation (1).

[0171] Total value = Ndata + n Nmax (1)

[0172] By configuring the light detection device 1 as described above, the number of bits required for the counter 60 can be reduced, which allows for a smaller area of ​​the counter 60. Furthermore, power consumption can be reduced. In this modified example, both reduced power consumption and smaller circuit area can be achieved.

[0173] (2-6. Variation Example 6)

[0174] Figures 16A to 16D This is a diagram illustrating an embodiment of the pixel arrangement of the light detection apparatus according to Modification 6. For example, the plurality of pixels P provided in the pixel section 100 of the light detection apparatus 1 include pixels that receive infrared light (IR pixels) and pixels that receive visible light. The IR pixels include light receiving elements 10 and are configured to receive and photoelectrically convert infrared light.

[0175] Embodiments of pixels that receive visible light include pixels (R pixels) provided with filters that allow red (R) light to pass through, pixels (G pixels) provided with filters that allow green (G) light to pass through, and pixels (B pixels) provided with filters that allow blue (B) light to pass through. For example, each of the R pixels, G pixels, and B pixels includes a light receiving element 10 and is configured to receive and photoelectrically convert incident light.

[0176] The color filter set in pixel P is not limited to primary color (RGB) filters, but can also be a complementary color filter such as cyan (Cy), magenta (Mg), yellow (Ye). IR pixels may include filters that allow infrared light to pass through. In addition, all or some pixels may not have filters set as needed.

[0177] In pixel section 100, for example, such as Figures 16A to 16C The illustrated embodiment repeatedly arranges multiple IR pixels, multiple R pixels, multiple G pixels, and multiple B pixels. As an example, the IR pixels can be arranged to replace some of the RGB pixels arranged in a Bayer array. It should be noted that the arrangement of pixel P is not limited to the embodiment shown in the figures, and any other arrangement is possible.

[0178] In the light detection device 1, for example, the IR pixel is configured to generate a pixel signal with an IR component and can be used for distance measurement via the TOF method. The R pixel, G pixel, and B pixel are configured to generate pixel signals with R components, G components, and B components, respectively.

[0179] In the light detection device 1, IR pixels and RGB pixels are provided, which allows for the simultaneous acquisition of visible light hue values ​​and distance measurement. By using the pixel signal of each pixel, the light detection device 1 is able to obtain an image (e.g., an RGB image) indicating both the object image and the distance image.

[0180] In the optical detection device 1, such as in Figure 16D In the embodiment shown, IRG pixels can be provided over the entire area of ​​the pixel section 100. By arranging IR pixels over the entire area of ​​the pixel section 100, the spatial resolution as a ranging sensor can be improved.

[0181] (2-7. Variation Example 7)

[0182] Figure 17 , Figure 18A and Figure 18B This is a diagram illustrating an embodiment of the configuration of the light detection device according to Modification 7. The light detection device 1 may have a stacked structure in which multiple semiconductor layers are stacked on top of each other. Figure 17 , Figure 18A and Figure 18B In the embodiment described herein, the light detection device 1 includes a first layer 101 and a second layer 102. The light detection device 1 has a configuration in which the first layer 101 and the second layer 102 are stacked on top of each other. The first layer 101 and the second layer 102 are stacked so that they overlap each other.

[0183] The photodetector 1 comprises multiple substrates (e.g., first layer 101 and second layer 102) including semiconductor substrates (e.g., silicon substrates or SOI substrates). For example, the first layer 101 (first layer) is provided with a photoreceiving element 10 for each pixel P of the pixel portion 100. In the first layer 101, as in... Figure 18A or Figure 18B In the embodiments shown, a plurality of light receiving elements 10 may be configured to be aligned in the horizontal direction (row direction) and the vertical direction (column direction).

[0184] The second layer 102 includes, for example, a readout circuit 20 for each pixel P, a pixel controller 110, etc. Figure 18A or Figure 18B The illustrated embodiment provides a readout circuit 20 for a region of a pixel P. A pixel controller 110 is provided, for example, in the peripheral region of a plurality of readout circuits 20 arranged in a matrix.

[0185] The light-receiving element 10 of each pixel P is disposed in the first layer 101, and the readout circuit 20, etc., is disposed in the second layer 102; therefore, the area of ​​the light-receiving element 10 can be secured, and the light detection device 1 can be more highly integrated. For example, as Figure 18AIn the embodiment shown, the pixel controller 110 can be arranged along the long side of the pixel section 100 (pixel array).

[0186] By placing the pixel controller 110 on the long side of the pixel unit 100, the wiring impedance (load capacitance, load resistance, etc.) of the wiring (such as the wiring for transmitting signal CK1 and the wiring for transmitting signal CK2) can be reduced. Therefore, the detection period of each pixel P can be accurately set.

[0187] Pixel controller 110 can be as follows Figure 18B The embodiment shown is provided along the short side of pixel segment 100. The signal processor 112, controller 113, etc., described above can be located in the second layer 102, or can be located in a different layer than the second layer 102.

[0188] Figures 19A to 19D This is a diagram used to explain another configuration embodiment of the light detection device according to Modification 7. The light detection device 1 may include a first layer 101, a second layer 102, and a third layer 103. The second layer 102 is disposed, for example, between the first layer 101 and the third layer 103. The light detection device 1 may have a structure in which the first layer 101, the second layer 102, and the third layer 103 are stacked on top of each other.

[0189] exist Figure 19A In the illustrated embodiment, the second layer 102 is provided with transistor Tr1 (clamping transistor) and voltage generator 140. Furthermore, the third layer 103 is provided with readout circuitry 20 for each pixel P and pixel controller 110. The transistor Tr1, acting as a high-voltage transistor, is arranged in the second layer 102, while the transistors of the readout circuitry 20, acting as low-voltage transistors, are arranged in the third layer 103, which improves area efficiency.

[0190] Voltage generator 140 can be arranged in the third layer 103, such as Figure 19B As shown. Furthermore, like transistor Tr1, the power supply unit 145 described above may include a high-voltage transistor. Therefore, like transistor Tr1, the power supply unit 145 including a high-voltage transistor can be arranged in the second layer 102. In this case, area efficiency can be improved.

[0191] As in Figure 19C or Figure 19D In the example shown, the readout circuit 20 can be separately configured in the second layer 102 and the third layer 103. For example, as Figure 19C As shown, the coupling circuit 30 and the output circuit 40 can be arranged in the second layer 102. Furthermore, for example, as... Figure 19DAs shown, the coupling circuit 30, output circuit 40, detection circuit 50, and AND circuit 55 can be arranged in the second layer 102.

[0192] exist Figure 19C or Figure 19D In the embodiment shown, compared to the case where the coupling circuit 30 and the output circuit 40 are arranged in the third layer 103, the capacitance between the second layer 102 and the third layer 103 (e.g., the capacitance added to node N1) can be reduced, and power consumption can be lowered. The generation of unwanted parasitic capacitances can be suppressed, and timing adjustments can be prevented from becoming difficult.

[0193] (2-8. Variation Example 8)

[0194] Figure 20 This is a diagram used to explain an embodiment of the pixel configuration of the light detection device according to Modified Example 8. Figure 20 In the embodiment shown, the cathode of the light receiving element 10 is electrically connected to the potential line L1. Furthermore, the anode of the light receiving element 10 is electrically coupled to the coupling circuit 30 and the output circuit 40.

[0195] The coupling circuit 30 includes, for example, an NMOS transistor and is electrically coupled in series between the photoreceiving element 10 and the potential line L2. The output circuit 40 may include, for example, a buffer. In this variation, the same effects as those described in the above embodiments can be achieved.

[0196] <3. Usage Examples>

[0197] For example, the light detection device 1 and the light detection system 200 described above can be used in various situations where light (such as visible light, infrared light, ultraviolet light, or X-rays) is sensed: Devices that take pictures for viewing, such as digital cameras, mobile devices with camera functions, etc.

[0198] Devices used in transportation include, for example, vehicle sensors that capture images of the front, rear, surrounding environment, and interior of a car to enable safe driving, such as automatic stopping and driver status recognition; surveillance cameras that monitor moving vehicles and roads; and distance sensors that measure distances between vehicles or other objects.

[0199] Devices used in home appliances, such as televisions, refrigerators, and air conditioners, are configured to capture the user's gestures in order to perform operations on the appliances based on those gestures; Devices used for healthcare and wellness, such as endoscopes and devices for angiography using infrared light.

[0200] Security devices, such as surveillance cameras for crime prevention and cameras for human authentication.

[0201] Devices used for beauty purposes, such as skin measuring instruments that take images of the skin, microscopes that take images of the scalp, etc.

[0202] Devices for sports, such as action cameras or wearable cameras used for sports activities.

[0203] Devices used in agriculture, such as cameras used to monitor the condition of fields or crops.

[0204] <4. Practical Application Examples>

[0205] (Practical application examples of mobile bodies)

[0206] The technology according to this disclosure (the technology) can be used in a variety of products. For example, the technology according to this disclosure can be implemented as a device mounted on any type of mobile body, such as a car, electric vehicle, hybrid electric vehicle, motorcycle, bicycle, personal mobility device, airplane, drone, ship, or robot.

[0207] Figure 21 This is a block diagram illustrating an example of a schematic configuration of a vehicle control system, which serves as an example of a mobile body control system to which the technology according to embodiments of this disclosure can be applied.

[0208] The vehicle control system 12000 includes multiple electronic control units interconnected via a communication network 12001. Figure 21 In the illustrated embodiment, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. Furthermore, examples of the functional configuration of the integrated control unit 12050 include a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface (I / F) 12053.

[0209] The drive system control unit 12010 controls the operation of devices related to the vehicle's drive system according to various programs. For example, the drive system control unit 12010 is used as a control device for drive force generating devices (such as internal combustion engines, drive motors, etc.) that generate drive force for the vehicle, drive force transmission mechanisms that transmit drive force to the wheels, steering mechanisms that adjust the vehicle's steering angle, and braking devices that generate braking force for the vehicle.

[0210] The body system control unit 12020 controls the operation of various devices supplied to the vehicle body according to various programs. For example, the body system control unit 12020 serves as a control device for keyless entry systems, smart key systems, power windows, or various lights such as headlights, taillights, brake lights, turn signals, fog lights, etc. In this case, radio waves or signals from various switches, which are alternatives to buttons, can be input to the body system control unit 12020. The body system control unit 12020 receives these input radio waves or signals and controls the vehicle's door locking devices, power windows, lights, etc.

[0211] The exterior information detection unit 12030 detects information about the exterior of the vehicle, including the vehicle control system 12000. For example, an imaging unit 12031 is connected to the exterior information detection unit 12030. The exterior information detection unit 12030 causes the imaging unit 12031 to capture images of the exterior of the vehicle and receives the captured images. In addition, the exterior information detection unit 12030 can also perform processing based on the received images, such as detecting people, vehicles, obstacles, signs, text on the road surface, etc., or detecting their distance.

[0212] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output an electrical signal as an image, or it can output an electrical signal as information about the measured distance. Furthermore, the light received by the imaging unit 12031 can be visible light, or it can be invisible light such as infrared light.

[0213] The in-vehicle information detection unit 12040 detects information about the interior of the vehicle. The in-vehicle information detection unit 12040 is connected, for example, to a driver state detection unit 12041 that detects the driver's state. The driver state detection unit 12041 includes, for example, a camera that captures images of the driver. Based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or concentration level, or determine whether the driver is drowsy.

[0214] The microcomputer 12051 can calculate control target values ​​for the drive force generating device, steering mechanism, or braking device based on information about the vehicle's interior or exterior obtained by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control designed to realize functions of an advanced driver assistance system (ADAS), including collision avoidance or shock absorption for the vehicle, following driving based on following distance, maintaining vehicle speed, collision warning, lane departure warning, etc.

[0215] In addition, the microcomputer 12051 can control the drive force generation device, steering mechanism, braking device, etc., based on the information about the outside or inside of the vehicle obtained by the external information detection unit 12030 or the internal information detection unit 12040, so as to perform cooperative control for autonomous driving, which enables the vehicle to drive autonomously without relying on the driver's operation.

[0216] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on information about the exterior of the vehicle obtained by the exterior information detection unit 12030. For example, the microcomputer 12051 can perform cooperative control aimed at preventing glare by controlling the headlights to switch from high beam to low beam based on the position of the vehicle in front or oncoming vehicle detected by the exterior information detection unit 12030.

[0217] The sound / image output unit 12052 sends an output signal of at least one of sound and image to an output device capable of visually or audibly notifying the vehicle occupants or the outside of the vehicle of information. Figure 21 In the embodiments, the audio speaker 12061, the display unit 12062, and the instrument panel 12063 are shown as output devices. For example, the display unit 12062 may include at least one of an on-board display and a head-up display.

[0218] Figure 22 This is a schematic diagram depicting an embodiment of the mounting position of the imaging unit 12031.

[0219] exist Figure 22 In the imaging unit 12031, there are imaging units 12101, 12102, 12103, 12104 and 12105.

[0220] Imaging units 12101, 12102, 12103, 12104, and 12105 are, for example, located on the front nose, side mirrors, rear bumper, and rear door of vehicle 12100, and on the upper part of the windshield inside the vehicle. Imaging unit 12101 located on the front nose inside the vehicle and imaging unit 12105 located on the upper part of the windshield primarily acquire images of the front of vehicle 12100. Imaging units 12102 and 12103 located on the side mirrors primarily acquire images of the sides of vehicle 12100. Imaging unit 12104 located on the rear bumper or rear door primarily acquires images of the rear of vehicle 12100. Imaging unit 12105 located on the upper part of the windshield inside the vehicle is mainly used to detect vehicles, pedestrians, obstacles, signals, traffic signs, lanes, etc., ahead.

[0221] Incidentally, Figure 22 An embodiment of the imaging range of imaging units 12101 to 12104 is described. Imaging range 12111 represents the imaging range of imaging unit 12101 installed at the front nose. Imaging ranges 12112 and 12113 represent the imaging ranges of imaging units 12102 and 12103 installed at the side mirrors, respectively. Imaging range 12114 represents the imaging range of imaging unit 12104 installed at the rear bumper or rear door. For example, a bird's-eye view of the vehicle 12100 viewed from above is obtained by superimposing image data captured by imaging units 12101 to 12104.

[0222] At least one of the imaging units 12101 to 12104 may have the function of obtaining distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of multiple imaging elements, or may be an imaging element having pixels for phase difference detection.

[0223] For example, the microcomputer 12051 can determine the distance to each three-dimensional object within the imaging range 12111 to 12114 and the time change of the distance (relative speed relative to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. This allows it to extract objects existing on the vehicle 12100's travel path, traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., equal to or greater than 0 km / h). Furthermore, the microcomputer 12051 can preset a following distance to stay ahead of the preceding vehicle and execute automatic braking control (including follow-stop control), automatic acceleration control (including follow-start control), etc. Therefore, cooperative control for autonomous driving can be executed, enabling the vehicle to drive autonomously without relying on driver operation.

[0224] For example, the microcomputer 12051 can classify three-dimensional object data related to three-dimensional objects into three-dimensional object data such as two-wheeled vehicles, standard-sized vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from imaging units 12101 to 12104, extract the classified three-dimensional object data, and use the extracted three-dimensional object data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around vehicle 12100 as obstacles that the driver of vehicle 12100 can visually recognize and obstacles that the driver of vehicle 12100 cannot visually recognize. Then, the microcomputer 12051 determines a collision risk indicating the risk of collision with each obstacle. If the collision risk is equal to or higher than a set value and therefore there is a possibility of collision, the microcomputer 12051 outputs a warning to the driver via audio speaker 12061 or display unit 12062, and performs forced deceleration or evasive steering via drive system control unit 12010. The microcomputer 12051 can thereby assist driving to avoid collisions.

[0225] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. The microcomputer 12051 can identify a pedestrian, for example, by determining whether a pedestrian exists in the images captured by the imaging units 12101 to 12104. This pedestrian identification is performed, for example, by extracting feature points from the images captured by the imaging units 12101 to 12104, which are infrared cameras, and by performing pattern matching processing on a series of feature points representing the outline of an object to determine whether it is a pedestrian. When the microcomputer 12051 determines that a pedestrian exists in the images captured by the imaging units 12101 to 12104 and thus identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 such that a square outline for emphasis is displayed superimposed on the identified pedestrian. The sound / image output unit 12052 can also control the display unit 12062 such that an icon representing the pedestrian is displayed at a desired location.

[0226] An embodiment of a mobile body control system applying the technology according to embodiments of the present disclosure has been described above. The technology according to embodiments of the present disclosure can be applied to, for example, the imaging unit 12031 in the aforementioned components. Specifically, for example, imaging device 1, etc., can be applied to the imaging unit 12031. Applying the technology according to the present disclosure to the imaging unit 12031 enables the acquisition of high-resolution captured images. This allows high-precision control to be performed using the captured images in the mobile body control system.

[0227] The present disclosure has been described above with reference to embodiments, modifications, usage examples, and practical application examples; however, the present technology is not limited to the above embodiments and various modifications can be made. For example, the above modifications have been described as modifications of the above embodiments; furthermore, the corresponding configurations of the modifications can be appropriately combined.

[0228] The light detection device according to an embodiment of this disclosure includes: a light receiving element configured to receive light and output current; a control circuit configured to output a first signal and a second signal; a coupling circuit disposed between the light receiving element and a first potential line and controlled by the first signal; and a detection circuit configured to output a third signal based on the current of the light receiving element in response to the second signal. Therefore, a light detection device with excellent performance can be realized.

[0229] It should be noted that the effects described in this specification are merely embodiments; the effects of this disclosure are not limited to those described in the specification, and this disclosure may have other effects. Furthermore, this disclosure may have the following configurations. (1)

[0231] A light detection device, comprising: A light receiving element is configured to receive light and output current. The control circuit is configured to output a first signal and a second signal; A coupling circuit is disposed between the optical receiving element and the first potential line and is controlled by a first signal; and The detection circuit is configured to output a third signal based on the current of the photoreceiving element in response to the second signal. (2)

[0233] According to the optical detection device in (1), wherein, The control circuit is configured to output a first signal to control the coupling circuit and to control the recharging of the optical receiving element. (3)

[0235] According to the optical detection device of (1) or (2), wherein, The control circuit is configured to output the first signal as a pulse signal. (4)

[0237] According to any one of (1) to (3) of the optical detection device, wherein, The control circuit is configured to output a second signal as a pulse signal. (5)

[0239] According to any one of (1) to (4) of the optical detection device, wherein, The control circuit is configured to change the output timing of the second signal. (6)

[0241] According to any one of (1) to (5) of the optical detection device, wherein, The control circuit is configured to change the time period from the transition timing of the first signal to the transition timing of the second signal. (7)

[0243] According to any one of (1) to (6) of the optical detection device, wherein, The control circuit is configured to repeatedly output a first signal as a pulse signal, and The control circuit is configured to repeatedly output a second signal as a pulse signal. (8)

[0245] According to any one of (1) to (7) of the optical detection device, wherein, The control circuit is configured to perform control that changes the time period from the transition timing of the first signal to the transition timing of the second signal. (9)

[0247] According to any one of (1) to (8) of the optical detection device, wherein, The detection circuit is configured to output a third signal in sync with the second signal. (10)

[0249] According to any one of (1) to (9) of the optical detection device, wherein, The first potential line is the power supply line, and The coupling circuit includes a switch that is electrically coupled in series between the optical receiving element and the first potential line. (11)

[0251] According to any one of (1) to (10) of the optical detection device, wherein, The detection circuit includes a trigger. (12)

[0253] The light detection device according to any one of (1) to (11) further includes: The output circuit is configured to output a voltage signal based on the current of the photodetector to the detection circuit. (13)

[0255] According to the optical detection device of (12), wherein, The detection circuit is configured to output a third signal based on the voltage signal during the time period from the transition timing of the first signal to the transition timing of the second signal. (14)

[0257] According to the light detection device of (12) or (13), wherein, The output circuit includes an inverter. (15)

[0259] The light detection device according to any one of (1) to (14) further includes: The counter is configured to count the third signal. (16)

[0261] The light detection device according to any one of (1) to (15) further includes: The processing circuit is configured to perform a count based on the third signal of each pixel, corresponding to the number of pixels that have received light. (17)

[0263] According to the optical detection device of (16), wherein, The processing circuit is configured to perform two or more counts in response to a pulse signal. (18)

[0265] The light detection device according to any one of (1) to (17) further includes: A transistor electrically coupled between a light-receiving element and a coupling circuit and including a gate supplied with a predetermined voltage. (19)

[0267] The light detection device according to any one of (1) to (18) further includes: The first layer includes multiple optical receiving elements; and The second layer includes one or more of the control circuit, coupling circuit, and detection circuit, and is configured to be stacked on the first layer. (20)

[0269] The light detection device according to any one of (1) to (19) further includes: The first pixel performs photoelectric conversion on infrared light; and The second pixel performs photoelectric conversion on visible light. (twenty one)

[0271] According to any one of (1) to (20) of the optical detection device, wherein, The light-receiving element is an avalanche photodiode. (twenty two)

[0273] A light detection system, comprising: A light source is configured to emit light toward an object; and A light detection device receives light from an object. The optical detection device includes: A light-receiving element is configured to receive light and output current. The control circuit is configured to output a first signal and a second signal. A coupling circuit is disposed between the light receiving element and the first potential line and is controlled by a first signal. The detection circuit is configured to output a third signal based on the current of the photoreceiving element in response to the second signal.

[0274] This application claims the benefit of Japanese priority patent application JP2024-023460, filed with the Japan Patent Office on February 20, 2024, the entire contents of which are incorporated herein by reference.

[0275] Those skilled in the art will understand that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents.

Claims

1. A light detection device, comprising: A light receiving element is configured to receive light and output current. The control circuit is configured to output a first signal and a second signal; A coupling circuit is disposed between the optical receiving element and the first potential line and is controlled by a first signal; as well as The detection circuit is configured to output a third signal based on the current of the optical receiving element in response to the second signal.

2. The optical detection device according to claim 1, wherein, The control circuit is configured to output the first signal to control the coupling circuit and to control the recharging of the optical receiving element.

3. The optical detection device according to claim 1, wherein, The control circuit is configured to output the first signal as a pulse signal.

4. The optical detection device according to claim 1, wherein, The control circuit is configured to output the second signal as a pulse signal.

5. The optical detection device according to claim 4, wherein, The control circuit is configured to change the output timing of the second signal.

6. The optical detection device according to claim 1, wherein, The control circuit is configured to change the time period from the transition timing of the first signal to the transition timing of the second signal.

7. The optical detection device according to claim 1, wherein, The control circuit is configured to repeatedly output the first signal as a pulse signal, and The control circuit is configured to repeatedly output the second signal as a pulse signal.

8. The optical detection device according to claim 1, wherein, The control circuit is configured to perform control that changes the time period from the transition timing of the first signal to the transition timing of the second signal.

9. The optical detection device according to claim 1, wherein, The detection circuit is configured to output the third signal synchronously with the second signal.

10. The optical detection device according to claim 1, wherein, The first potential line is a power supply line, and The coupling circuit includes a switch connected in series between the optical receiving element and the first potential line.

11. The optical detection device according to claim 1, wherein, The detection circuit includes a trigger.

12. The optical detection device according to claim 1, further comprising: The output circuit is configured to output a voltage signal based on the current of the optical receiving element to the detection circuit.

13. The optical detection device according to claim 12, wherein, The detection circuit is configured to output the third signal based on the voltage signal during the time period from the transition timing of the first signal to the transition timing of the second signal.

14. The optical detection device according to claim 12, wherein, The output circuit includes an inverter.

15. The optical detection device according to claim 1, further comprising: A counter is configured to count the third signal.

16. The optical detection device according to claim 1, further comprising: The processing circuit is configured to perform a count based on the third signal for each pixel, corresponding to the number of pixels that have received light.

17. The optical detection device according to claim 16, wherein, The processing circuit is configured to perform two or more counts in response to a pulse signal.

18. The optical detection device according to claim 1, further comprising: A transistor electrically coupled between the light-receiving element and the coupling circuit and including a gate supplied with a predetermined voltage.

19. The optical detection device according to claim 1, further comprising: The first layer includes multiple optical receiving elements; as well as The second layer includes one or more of the control circuit, the coupling circuit, and the detection circuit, and is configured to be stacked on the first layer.

20. The optical detection device according to claim 1, further comprising: The first pixel performs photoelectric conversion on infrared light; as well as The second pixel performs photoelectric conversion on visible light.

21. The optical detection device according to claim 1, wherein, The light-receiving element is an avalanche photodiode.

22. A light detection system, comprising: The light source is configured to emit light toward the object; as well as A light detection device receives light from the object. The optical detection device includes: A light-receiving element is configured to receive light and output current. The control circuit is configured to output a first signal and a second signal. A coupling circuit, disposed between the light-receiving element and the first potential line and controlled by the first signal, and The detection circuit is configured to output a third signal based on the current of the optical receiving element in response to the second signal.

Images