| 摘要 |
PURPOSE:To control focusing swiftly in spite of the case of extreme deviation from the focusing state by providing main image pickup element and subimage pickup element on the optical path of an image forming optical system, arithmetically processing the sharpness signals thereof, and generating a control signal for position regulation of the optical system. CONSTITUTION:The image of an object is formed on a main image pickup element 21 by means of an image pickup lens 11, and is also projected to subimage pickup elements 31, 41 disposed at the front focus and the rear focus by means of a beam splitter 12. The outputs thereof go through high-pass filters 22-42, gates 23-43, detectors 24-44, and crest values P, Q, R are inputted to a controller 50. The output of the detector 24 is extractred by the gate 25 synchronously with the elements 31, 41. In the controller 50, logical operations are excuted, and by the output signal W thereof, the lens 11 is driven via a driving mechanism 61, and the position of the lens 11 is inputted via a position detector 62 to the controller 50. Thereby, the focusing is controlled swiftly in spite of the case of extreme deviation from the fucusing state. |
