| 摘要 |
PURPOSE:To exactly prevent hunting which is apt to occur in case of low luminance, by providing a circuit for making a driving direction signal invalid for a prescribed time even if said signal is outputted, once it has been decided to be in a focusing state. CONSTITUTION:A luminous flux which has passed through the right and left halves of a focusing lens 11 forms an image on CCDs 16A, 16B. A picture signal is stores in memories 22A, 22B through binary-encoders 21A, 21B, its data is made to take correlation by a correlator 23, focusing or nonfocusing is decided from a peak position of a correlation output by a peak detector 24, also a moving direction of the lens 11 is decided, and a focusing signal and a driving signal are sent to a driving circuit 31 at the time of focusing and nonfocusing, respectively. When the focusing signal C is sent from a magnitude comparator 131 of a driving direction detector 25, even if driving signals (a), (b) are outputted, a hunting preventing circuit 50 makes them invalid for a prescribed time, and stops a motor 32 through the driver 31. In this way, hunting of the motor 32 is prevented exactly. |
