Patent ID: 7196311

Claim:
A semiconductor photosensor comprising: a semiconductor substrate; a first photodiode formed on the semiconductor substrate; a second photodiode formed on the semiconductor substrate; a first amplifier circuit configured to amplify photocurrent from the first photodiode, the first amplifier circuit being formed on the semiconductor substrate; a second amplifier circuit configured to amplify photocurrent from the second photodiode, the second amplifier circuit being formed on the semiconductor substrate and having an amplifying characteristic substantially identical to that of the first photodiode; an infrared transmissive filter configured to attenuate visible light components relative to infrared light components in incident light, the infrared transmissive filter being provided on the second photodiode; and a subtraction circuit configured to output a difference between an output of the first amplifier circuit and an output of the second amplifier circuit, the subtraction circuit being formed on the semiconductor substrate, a distance from a first side face of the semiconductor substrate to a center of the first photodiode being substantially equal to a distance from a second side face of the semiconductor substrate to a center of the second photodiode, the second side face being opposed to the first side face.