Photoelectric conversion element, light receiving device, light receiving system, and distance measuring device

A light receiving device that acquires luminance information of incident light, comprising:

• a photoelectric conversion element, which detects and converts the incident light into photoelectrons;
• a charge accumulating unit for accumulating photoelectrons generated by the photoelectric conversion element;
• a capacitor that stores the photoelectrons at a fixed time period;
• a charge discharging unit that discharges the photoelectrons;
• a first metal-oxide-semiconductor (MOS)-type switching element disposed between the charge accumulating unit and the capacitor for causing the photoelectrons accumulated in the charge accumulating unit to migrate toward the capacitor;
• and
• a second MOS-type switching element disposed between the charge accumulating unit and the charge discharging unit for controlling discharge of the photoelectrons from the charge accumulating unit to the charge discharging unit,
• wherein the photoelectric conversion element comprises:
• an embedded photodiode embedded in a semiconductor substrate;
• and
• a plurality of MOS diodes having electrodes formed on the semiconductor substrate with an insulator therebetween,
• wherein the embedded photodiode has a comb-like shape when viewed from an upper surface thereof, in which plural branch portions are branched from one portion,
• the electrodes of the MOS diodes are nested, respectively, between the plural branch portions of the embedded photodiode when viewed from the upper surface thereof, and
• the photoelectrons from the photoelectric conversion element are transferred to the capacitor by selectively controlling opening or closing of the first MOS-type switching element and the second MOS-type switching element, wherein luminance information of incident light is acquired based on a charge amount of the photoelectrons transferred to the capacitor.