| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a focus detector capable of properly detecting focuses of optical systems. <P>SOLUTION: The focus detector comprises: an imaging unit 22 for imaging images by optical systems 31, 32 and 33 including focus adjustment optical systems, and outputting image signals; a phase difference detection unit provided on a light receiving surface of the imaging unit 22 to repeatedly detect the shift amount of image surfaces by the optical systems 31, 32 and 33; a contrast detection unit for detecting focus states of the optical systems 31, 32 and 33 on the basis of the image signals outputted from the imaging unit 22; a drive unit 36 for driving the focus adjustment optical system 32 in optical axis directions of the optical systems 31, 32 and 33; and a control unit 21 for executing scan driving making the phase difference detection unit and the contrast detection unit detect the focus states of the optical systems 31, 32 and 33 while making the drive unit 36 drive the focus adjustment optical system 32 in a prescribed direction when reliability of the shift amount detected by the phase difference detection unit is continuously less than a prescribed first threshold for a prescribed number of times as a result that the phase difference detection unit is made to detect the focus states of the optical systems 31, 32 and 33. <P>COPYRIGHT: (C)2013,JPO&INPIT |
