A light detecting device includes first pixel circuitry including a first avalanche photodiode, and second pixel circuitry including a second avalanche photodiode, a first delay circuit including an input coupled to a cathode of the second avalanche photodiode, a first circuit including a first input coupled to the cathode of the second avalanche photodiode, and a second input coupled to an output of the first delay circuit. The light detecting device includes a control circuit coupled to an output of the first circuit and configured to control a potential of an anode of the first avalanche photodiode based on the output of the first circuit. The control circuit is configured to control a potential of an anode of the second avalanche photodiode based on the output of the first circuit.

In a light detection device and a distance measuring system that obtain a distance from a round-trip time of light, a distance measurement error is reduced while a dead time is shortened. A logic gate outputs an output signal on the basis of a result of comparison between an input voltage depending on a voltage of one terminal of the cathode or the anode of an avalanche photodiode and a predetermined threshold voltage. A voltage limiting transistor limits the input voltage. A rapid charging transistor, in which a film thickness of a gate oxide film is less than that of the voltage limiting transistor, supplies a charging current to the avalanche photodiode in accordance with a predetermined pulse signal. A pulse generation unit generates the pulse signal on the basis of the output signal and supplies the pulse signal to the rapid charging transistor.

A light-receiving apparatus (1a) includes a counting unit (11), a setting unit (12), and an acquiring unit (13). The counting unit is configured to measure a detection number of times that represents the number of times incidence of a photon to a light-receiving element has been detected within an exposure period and to output a counted value. The setting unit is configured to set a cycle of updating time information in accordance with an elapsed time during the exposure period. The acquiring unit is configured to acquire the time information indicating a time at which the counted value reaches a threshold before the exposure period elapses.

A multispectral sensor array can include a combination of ranging sensor channels (e.g., LIDAR sensor channels) and ambient-light sensor channels tuned to detect ambient light having a channel-specific property (e.g., color). The sensor channels can be arranged and spaced to provide multispectral images of a field of view in which the multispectral images from different sensors are inherently aligned with each other to define an array of multispectral image pixels. Various optical elements can be provided to facilitate imaging operations. Light ranging/imaging systems incorporating multispectral sensor arrays can operate in rotating and/or static modes.

An imaging device may include single-photon avalanche diodes (SPADs). To improve the sensitivity and signal-to-noise ratio of the SPADs, light scattering structures may be formed in the semiconductor substrate to increase the path length of incident light through the semiconductor substrate. To mitigate crosstalk, multiple rings of isolation structures may be formed around the SPAD. An outer deep trench isolation structure may include a metal filler such as tungsten and may be configured to absorb light. The outer deep trench isolation structure therefore prevents crosstalk between adjacent SPADs. Additionally, one or more inner deep trench isolation structures may be included. The inner deep trench isolation structures may include a low-index filler to reflect light and keep incident light in the active area of the SPAD.

A method of building a moving average histogram of photon times of arrival includes, for each time interval in first and second subsets of time intervals, latching a time reference corresponding to a time of receipt of an avalanche timing output signal of a single-photon avalanche diode (SPAD), and advancing a count stored at a memory address corresponding to the latched time reference. The memory address corresponds to a range of time references. The method further includes reading and clearing a first set of counts after the first subset of time intervals; phase-shifting the sequence of time references with respect to a set of memory addresses after the first subset of time intervals; reading and clearing a second set of counts after the second subset of time intervals; and building the moving average histogram using at least the first and second sets of counts.

A photon detection device including: a silicon photomultiplier (SiPM) configured to generate a detected signal when the SiPM absorbs a photon; an amplifier; and a transmission line stub between the SiPM and amplifier input. The SiPM connection is configured to transmit the detected signal to the amplifier and a transmission line stub is also configured to receive the SiPM signal and generate a time-delayed reflected signal back into the amplifier input; wherein the amplifier is configured to amplify a combination of the detected signal and the time-delayed reflected signal. The end of the transmission line stub is terminated with a complex impedance that can simultaneously absorb some components of the SiPM pulse response, and reflect others.

A light receiving device of the present disclosure includes: a pixel array unit having a plurality of pixels 50.sub.1 to 50.sub.4 each including a light receiving unit 50.sub.1 to 50.sub.4 that generates a signal according to reception of photons; a first switch unit that 61.sub.1 to 61.sub.4 recharges the light receiving unit 50.sub.1 to 50.sub.4; and a recharge control unit 64 that controls the first switch unit 61.sub.1 to 61.sub.4 according to output of the light receiving unit 50.sub.1 to 50.sub.4, and the recharge control unit 64 is shared among the plurality of pixels 50.sub.1 to 50.sub.4. By this sharing of the recharge control unit 64, since the circuit area of the circuit unit 60 per pixel can be reduced, the aperture ratio can be increased while miniaturizing the pixel 50. Preferably, the recharge control unit 64 includes a four-input OR circuit 641 and a recharge signal generation circuit 642. The OR circuit 641 obtains the OR of the logic signals retrieved from each cathode electrode of the SPAD sensors 50.sub.1 to 50.sub.4 supplied through the comparators 63.sub.1 to 63.sub.4. The OR output of the OR circuit 641 is supplied to the recharge signal generation circuit 642. The recharge signal generation circuit 642 generates the recharge signal RCHG by delaying the OR output of the OR circuit 641 by a predetermined delay time, and supplies the recharge signal RCHG to the first switch units 61.sub.1 to 61.sub.4. As a result, the recharge control unit 64 performs the recharge control in response to the OR signal of the logic signal whose logic is inverted at the time when photons are incident on one or more of the SPAD sensors 50.sub.1 to 50.sub.4. Furthermore, a distance measuring device of the present disclosure includes: a light source that irradiates an object to be measured with light; and a light receiving device that receives light reflected by the object to be measured, and the light receiving device includes the light receiving device having the above configuration.

An avalanche photodiode sensor according to an embodiment includes a first semiconductor substrate and a second semiconductor substrate bonded to a first surface of the first semiconductor substrate, wherein the first semiconductor substrate includes a plurality of photoelectric conversion portions arranged in a matrix and an element separation portion for element-separating the plurality of photoelectric conversion portions from each other, the plurality of photoelectric conversion portions include a first photoelectric conversion portion, the element separation portion has a first element separation region and a second element separation region, the first photoelectric conversion portion is arranged between the first element separation region and the second element separation region, the first semiconductor substrate further includes a plurality of concave-convex portions arranged on a second surface opposite to the first surface and arranged between the first element separation region and the second element separation region, and the second semiconductor substrate includes a reading circuit connected to each of the photoelectric conversion portions.

An imaging device includes a sensor array with a number of pixels. In an embodiment, the imaging device can be operated by capturing a first low-spatial resolution frame using a subset of pixels of the sensor array and then capturing a second low-spatial resolution frame using the same subset of pixels of the sensor array. A first depth map is generated using raw pixel values of the first low-spatial resolution frame and a second depth map is generated using raw pixel values of the second low-spatial resolution frame. The first depth map can be compared to the second depth map to determine whether an object has moved in a field of view of the imaging device.