AUTOMATIC CAMERA FOCUSING MECHANISM

摘要

PURPOSE:To obtain an automatic focusing mechanism for a camera for performing a focusing action at high speed by starting the driving of a photographic lens from the computation starting time of a correlative value and stopping the movement of the lens when sequentially computed correlative value becomes a minimum (or maximum) value. CONSTITUTION:Image sensors 10 and 11 photoelectrically converts an optical image from an object and generates analog signals R(t) and B(t) corresponding to a pair of pattern of the optical image, which are inputted in an analog correlative computing element 12. When the correlative computation is started in the analog correlative computing element 12, a polarity change discrimination circuit 13 and a driving circuit 14 move the photographic lens from an initial position in a specified direction at specified speed at said starting time. When the correlative value obtained by the computing element 12 becomes the minimum (or maximum), the driving of the lens is stopped, so that focusing action can be completed at high speed without a delay simultaneously with the processing of the correlative computation.