Patent ID: 7773145
Filing Date: 2010-08-10
Classification: G03B

Abstract:
1. An auto focus unit, comprising: a pursuit block that pursues movements of a targeted object within a frame of an entire image to be photographed; a scanning area setting block that designates at least a part of an object-area as a scanning area at a first time, an image of the targeted object being at said object-area within said frame of said entire image, said scanning area being used for focusing an image of an object on a light-receiving surface, said scanning area setting block resets said scanning area after said first time to a new location within said frame of said entire image to which said targeted object has moved; a change area setting block that designates an area of a predetermined size, based on the location of said targeted object within said frame of said entire image, as a change area at said first time, the scanning area being smaller than the change area and being included in the change area, the change area and the scanning area being separately designated, a time period during which the scanning area is designated at least partially overlaps with a time period during which the change area is designated; a permission block that controls said scanning area setting block to again reset said scanning area when said location, to which said targeted object has moved, within said frame of said entire image after said first time, is outside of said change area; and a lens driver that drives a focus lens to move so that an optical image of said scanning area is focused upon said light-receiving surface.