| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an automatic focusing device capable of adjusting a focusing position at a high speed while keeping certain precision. <P>SOLUTION: The automatic focusing device is equipped with a line exposure type imaging element (CMOS image sensor) which converts an optical image formed through a focus lens into an image signal, a lens drive section which moves the focus lens along the optical axis, an AF detection section which calculates an AF evaluated value based upon an image signal of an evaluation region previously set in an imaging region obtained by the imaging element, an exposure time calculating means of calculating the shortest exposure time T<SB>exp</SB>such that an exposure period of the evaluation region does not overlap a drive period of the focus lens based upon a time corresponding to the vertical width of the evaluation region and a drive time T<SB>m</SB>of the focus lens needed for one frame of the imaging region, and a control section which controls the imaging element and lens drive section according to the calculated shortest exposure time T<SB>exp</SB>. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
