Patent ID: 7634185
Filing Date: 2009-12-15
Classification: G03B

Abstract:
1. A focusing device comprising: a focus-lens driving unit configured to drive a focus lens; a control unit configured to control the focus-lens driving unit to move the focus lens through a predetermined range, to determine a state of focus on the basis of a signal output from an image pickup unit, the signal being acquired in association with movement of the focus lens through the predetermined range, and to control the focus-lens driving unit so that an image of an object is in focus; and a storing unit configured to store a position of the focus lens in focus acquired by the control unit, wherein the control unit is configured to calculate, on the basis of the position of the focus lens stored in the storing unit, a datum point of the range of movement of the focus lens and to shift the range of movement of the focus lens in response to the calculated datum point in a direction in which the object moves.