| 摘要 |
<p>A charge generated in response to the quantity of the incident light into the photodiodes PD is accumulated in an integrating capacitor of an integrating circuit 10 , and a voltage V<SUB>10 </SUB>in response to the quantity of the accumulated charge is outputted. The voltage V<SUB>10 </SUB>is inputted into a comparison circuit 20 and is compared with a prescribed threshold voltage therein. When the inputted voltage reaches the threshold voltage, a saturation signal F<SUB>1 </SUB>showing the same is outputted. A certain quantity of charge whose polarity is inverse to that of the charge accumulated in the integrating capacitor of the integrating circuit 10 is injected into the integrating n capacitor by the charge injecting circuit 30 on the basis of the saturation signal. The number of times of the voltage V<SUB>10</SUB>, which is outputted from the integrating circuit 10 , reaching the threshold voltage is counted by the counting circuit 40 on the basis of the saturation signal outputted from the comparison circuit 20 , wherein a quantity of incident light is detected on the basis of the counted made by the counting circuit 40 and the output voltage value from the integrating circuit 10.</p> |
