US 7,580,208 B2
Focus adjustment apparatus
Naoto Nakahara, Saitama (Japan)
Assigned to Hoya Corporation, Tokyo (Japan)
Filed on Nov. 29, 2006, as Appl. No. 11/564,468.
Claims priority of application No. P2005-348366 (JP), filed on Dec. 01, 2005.
Prior Publication US 2007/0127138 A1, Jun. 07, 2007
Int. Cl. G02B 7/02 (2006.01)
U.S. Cl. 359—824  [359/811] 13 Claims
OG exemplary drawing
 
1. A focus adjustment apparatus comprising:
an imaging device which captures object images via a photographing lens;
a lens driving device which moves a focusing lens group included in said photographing lens along an optical axis thereof;
a manual focus adjustment device which actuates said lens driving device to move said focusing lens group in response to a manual operation;
a focus detection device which causes said imaging device to capture an object image to determine a contrast value thereof each time said focusing lens group moves along said optical axis by a predetermined amount of movement while said focusing lens group is moved via said lens driving device due to said manual operation, and which detects an in-focus position of said focusing lens group in accordance with contrast values detected by said focus detection device at different lens positions on said optical axis of said focusing lens group; and
a controller which moves said focusing lens group to said in-focus position via said lens driving device if a deviation exists between a stopped position of said focusing lens group and said in-focus position when said focusing lens group stops moving in response to a release of said manual operation.