Patent ID: 7755686

Claim:
A physical quantity distribution detecting apparatus comprising: a sensor array in which a plurality of unit sensors for sensing physical quantity are two-dimensionally arranged in a matrix, each unit sensor generating an analog signal; and analog-to-digital conversion means that includes a plurality of comparators for comparing the analog signal read from the unit sensor with a reference signal, the analog-to-digital conversion means generating a digital signal by measuring a period of time or measuring a signal corresponding to the period of time of each comparison output of the plurality of comparators, wherein, each of the plurality of comparators includes a differential input unit that compares the corresponding analog signal with the reference signal and an inverted buffer unit that inverts the polarity of an output of the differential input unit, each differential input unit is coupled to its corresponding inverted buffer unit by a signal line, and each of the plurality of comparators includes at least one capacitor element connected between its signal line and a constant-voltage line, the constant voltage line being coupled to the differential input unit and the inverted buffer unit.