| 摘要 |
PURPOSE:To obtain the device which can execute a correction of the misalignment quantity of an image formation point on the photodetecting surface and a correction of a distortion of a distance measuring operation output caused by a bias current of a detecting circuit by adjusting electrically the bias current of the circuit. CONSTITUTION:A detecting circuit 22 superposes a photocurrent which a photodetector 1 photodetects a reflecting light beams and generates, on a bias current and detects it. An arithmetic output circuit 23 calculates distance information of an object from an output of the photocurrent which has been superposed on the bias current and outputs it. Also, a bias current ratio setting circuits constituted of transistors 12, 15 and 18 and diodes 13, 14, and sets a bias current ratio so as to be proportional to a reciprocal number of a distance of the object to be photographed extending over the whole area of a distance measuring range. In such a way, a fact that the distance measurement becomes impossible due to a relative misalignment between the photodetector 1 and a light projecting element 68 and a distortion of a distance measuring operation output caused by the bias current of the circuit 22 is corrected by setting the bias current ratio, and a linear relation of the reciprocal number of the distance of the object and the operation output is held. |
