Image position detector

摘要

An image position detector includes a light receiving element for receiving an image of an object and for producing an electric signal generated by the image, and a signal processing circuit for processing the electric signal and for producing a position signal representing a position of the image on the light receiving element. The light receiving element is defined by a semiconductor device having an n-type substrate and p-type region formed in the substrate. A current generated between the n-type substrate and p-type region is in relation to the distance to the image from the p-type region. The signal processing circuit receives the generated current and determines the position of the image by the level of the generated current.