BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a photoelectric conversion device.

Description of the Related Art

As photon detection elements, an avalanche photodiode (APD) or a single photon avalanche diode (SPAD) that multiplies charges generated by incidence of a photon with avalanche breakdown is known. These photon detection elements are utilized for image capturing or ranging as a photon count sensor that counts detected photons. In general, a pixel of a sensor using a SPAD is formed of a photon detection element, a quench element, a waveform shaper, and a signal processing circuit. The avalanche current occurring when the photon detection element detects a photon causes a voltage drop at the quench element, and a detection signal is generated. The detection signal is shaped into a pulsed waveform by the waveform shaper and input to the signal processing circuit. Japanese Patent Application Laid-Open No. H07-067043 discloses that the operation of the pixel is controlled by a control signal, thereby a count range is effectively expanded, and the dynamic range is expanded.

However, the function of the signal processing circuit disclosed in Japanese Patent Application Laid-Open No. H07-067043 is limited to counting of a detection signal as with the conventional photon count sensor.

SUMMARY OF THE INVENTION

The present invention intends to provide a photoelectric conversion device that can perform various calculation processes at a signal processing circuit.

According to one aspect of the present invention, provided is a photoelectric conversion device including a plurality of pixels arranged in an array to form a plurality of rows and a plurality of columns. Each of the plurality of pixels includes a photon detection element that outputs an output signal generated by avalanche multiplication in accordance with incidence of a photon, a quench element connected to the photon detection element, a waveform shaper that is connected to the photon detection element and generates a detection signal based on the output signal, and a signal processing circuit that performs signal processing on the detection signal output from the waveform shaper. The signal processing circuit includes a counting unit that performs a counting process of counting the detection signal output from the waveform shaper and a calculation unit that performs a predetermined calculation process on a count result output from the counting unit.

Further, according to another aspect of the present invention, provided is a photoelectric conversion device including a plurality of pixels arranged in an array to form a plurality of rows and a plurality of columns. Each of the plurality of pixels includes a photon detection element that outputs an output signal generated by avalanche multiplication in accordance with incidence of a photon, a quench element connected to the photon detection element, a waveform shaper that is connected to the photon detection element and generates a detection signal based on the output signal, and a signal processing circuit that performs signal processing on the detection signal output from the waveform shaper. The signal processing circuit includes a calculation unit that performs a predetermined calculation process on the detection signal output from the waveform shaper and a counting unit that performs a counting process on a calculation result output from the calculation unit.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

