| 摘要 |
PURPOSE:To eliminate a need for a mechanism finely changing an optical path length and to reduce the size of the device by applying respective driving signals of respective circuits detecting a focus/non-focus state to a piezo-electric actuator while superimposing them on each other. CONSTITUTION:A video signal from an imaging device 20 is distributed to an out-of-focus detection circuit 24 and a camera circuit 43. The circuit 42 extracts the high frequency component of the video signal with a BPF, discriminates the focus/non-focus state based on the obtained value and supplies focusing information corresponding to it to an actuator driving circuit 44. The circuit 44 converts the focusing information into an actuator driving signal and applies it to a piezo-electric actuator 30. The driving signal from a fine oscillation driving signal generator 45 is superimposed on the driving signal from the circuit 44 and applied to the actuator 30 by an adder 46. Thus, since the actuator 30 serves both as a mechanism making focusing and as a mechanism finely changing the optical path length for obtaining a necessary image signal for detecting focusing, the number of items serving as driving mechanisms can be reduced. |
