| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a photo-detection device of a small size and good sensitivity. <P>SOLUTION: A photo-detection device 10, in which cathode terminals of photodiodes 1 and 2 with different spectroscopic characteristics or a photodiode 1 provided with an optical filter and a photodiode 2 provided with a light shielding layer are open ended, detects light intensity in a desired wavelength region from a differential component of electric charges accumulated in the photodiodes during a fixed period of time. Since the photodiodes 1 and 2 accumulate electric charges, the photodiodes can accumulate and obtain electric charges required for detection even in the case where a photoelectric current is small, whereby semiconductor devices forming the photodiodes 1 and 2 can be miniaturized and enhanced in detection performance thereof. Furthermore, an electric charge accumulation time is made variable according to the light intensity so that a wide dynamic range can be realized, elements necessary for differential component detection are intermittently driven at the time of detecting the differential component so that electric power consumption can be suppressed, or an output is averaged so that the influence of a flicker can be reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT |
