Hamamatsu-photonics K.k.

Waseda University

Shunsuke Adachi

Terumasa Nagano

Shigeyuki Nakamura

Shinya Iwashina

Michito Hirayanagi

Koei Yamamoto

Takashi Baba

Ryutaro Tsuchiya

Takuya Fujita

Masanori Okada

Tsuyoshi Ohta

Hiroki Suzuki

Kenichi Sato

Shinji Ohsuka

Shogo Kamakura

Jun Kataoka

Toru Nishiyama

Tetsuya Uchiyama

Each of a plurality of cells includes at least one avalanche photodiode. A light projecting unit is arranged to project light having a cross-sectional shape whose longitudinal direction corresponds to a first direction. The light projecting unit is arranged to scan the light along a second direction intersecting the first direction such that the reflected light is incident on, among N cell groups each of which includes M cells aligned in a row direction, each cell group or each plurality of cell groups. A controller is arranged to apply, in accordance with the incidence of the reflected light, a bias voltage that makes the avalanche photodiode operate in a Geiger mode to each cell group or each plurality of cell groups, and is arranged to read signals from cells included in the cell group or the plurality of cell groups to which the bias voltage has been applied.

Photodetection device, semiconductor photodetection element, and method for driving semiconductor photodetection element

In a light detection device, switches are connected in parallel to each other. Each of the switches is connected to an APD. A read line electrically connects the switch and a signal processor to each other. The switch is configured such that a second terminal is connected to the read line and a voltage greater than or equal to a breakdown voltage is applied to the APD in a conductive state. The switch is configured such that the second terminal is not connected to the read line and a voltage greater than or equal to a breakdown voltage is applied to the APD in the conductive state. The switch is configured such that the second terminal is not connected to the read line and a voltage less than a breakdown voltage is applied to the APD in the conductive state.

Light detection device

In a light detection device, each pixel includes a plurality of APDs. Each APD forms a light receiving region and is configured to operate in a Geiger mode. The plurality of APDs forms a plurality of light receiving regions arranged in a direction along a main surface in a pixel area α occupied by a corresponding pixel among a plurality of pixels. The MOS switch circuit region overlaps with the plurality of light receiving regions when viewed from a Z-axis direction. When viewed from the Z-axis direction, the area of the MOS switch circuit region is greater than the area of one light receiving region formed in the pixel area, and less than or equal to the area of the pixel area. A plurality of APDs included in each pixel is electrically connected in parallel to each other and each is connected to a MOS switch circuit.

Light detection device with a plurality of avalanche photodiodes and MOS switch circuits

A photodetecting device includes a semiconductor substrate including a one-dimensionally distributed plurality of pixels. The photodetecting device includes, for each pixel, a plurality of avalanche photodiodes arranged to operate in Geiger mode, a plurality of quenching resistors electrically connected in series with the respective avalanche photodiodes, and a signal processing unit arranged to process output signals from the plurality of avalanche photodiodes. Light receiving regions of the plurality of avalanche photodiodes are two-dimensionally distributed for each pixel. Each signal processing unit includes a gate grounded circuit and a current mirror circuit electrically connected to the gate grounded circuit. The gate grounded circuit is electrically connected to the plurality of avalanche photodiodes of the corresponding pixel via the plurality of quenching resistors. The current minor circuit is arranged to output a signal corresponding to output signals from the plurality of avalanche photodiodes.

A photodetecting device includes a semiconductor photodetecting element including a plurality of pixels distributed two-dimensionally and a mount substrate including a plurality of signal processing units arranged to process output signals from the corresponding pixels. The semiconductor photodetecting element includes, for each of the pixels, a plurality of avalanche photodiodes arranged to operate in Geiger mode, a plurality of quenching resistors each electrically connected in series with a respective avalanche photodiodes, and a through-electrode electrically connected to the plurality of quenching resistors. Each of the signal processing units includes a current mirror circuit electrically connected to the plurality of avalanche photodiodes via the corresponding through-electrode and arranged to output a signal corresponding to output signals from the plurality of avalanche photodiodes. The number of signal processing units included on the mount substrate is more than the number of light receiving regions in each of the pixels.

Photodetecting device with weak light signal detection and low power consumption

A readout circuit for reading out an output current from a photoelectric conversion element which collectively outputs currents generated in a plurality of pixels, each of which includes an avalanche photodiode, includes a current mirror circuit configured to receive the output current and output first and second currents having magnitudes in proportion to the output current, a photon counting circuit configured to count the number of photons incident on the photoelectric conversion element on the basis of the first current, an integral circuit configured to integrate the second current to generate a voltage signal, and a signal processing unit configured to determine a magnitude of light incident on the photoelectric conversion element on the basis of a counting result output from the photon counting circuit and a magnitude of the voltage signal output from the integral circuit.

Readout circuit

A Compton camera includes a scattering detection unit, an absorption detection unit, a signal processing unit, a first shield unit, and a second shield unit. The scattering detection unit detects Compton scattering of incident radiation emitted from a radiation source. The absorption detection unit detects absorption of incident radiation that has undergone Compton scattering at the scattering detection unit. The signal processing unit obtains an image of the radiation source based on coincident detection events of Compton scattering of radiation at the scattering detection unit and absorption of radiation at the absorption detection unit. The first and second shield units are provided between the scattering detection unit and the absorption detection unit. The first shield unit selectively allows forward-scattered radiation to pass and selectively blocks back-scattered radiation.

Compton camera

A reverse bias voltage is applied to a photodiode array provided with a plurality of avalanche photodiodes operated in Geiger mode and with quenching resistors connected in series to the respective avalanche photodiodes. Electric current is measured with change of the reverse bias voltage applied, and the reverse bias voltage at an inflection point in change of electric current measured is determined as a reference voltage. A voltage obtained by adding a predetermined value to the determined reference voltage is determined as a recommended operating voltage.

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Hamamatsu, Japan

Shunsuke Adachi