Patent ID: 8872089

Claim:
A solid-state image sensing device comprising: a first photoelectron storage unit for storing a photoelectron that is generated by photoelectric conversion during a first exposure period in which only ambient light is detected for a predetermined time while a subject is not illuminated with an emitted light by an illuminating unit for illuminating the subject for measuring a distance to the subject; a second photoelectron storage unit for storing a photoelectron that is generated by photoelectric conversion during a second exposure period for the predetermined time, including a period during which the emitted light reflected from the subject and the ambient light are detected; and an AD converter for converting an analog signal into a digital signal, wherein the AD converter includes: a first comparator for comparing a reference voltage supplied from a reference voltage generator for generating the reference voltage, the level of which gradually varies, and a first analog signal from the first photoelectron storage unit with each other, and outputting a signal depending on the first analog signal; a second comparator for comparing the reference voltage supplied from the reference voltage generator and a second analog signal from the second photoelectron storage unit with each other, and outputting a signal depending on the second analog signal; a differential circuit for determining a difference between the signal depending on the first analog signal and the signal depending on the second analog signal, and outputting a differential signal representing the difference; and a first counter circuit for counting pulses of a pulse train depending on the differential signal, and converting the differential signal into a digital signal.