Patent ID: 6795122
Filing Date: 2004-09-21
Classification: H04N

Abstract:
A focal-plane shutter for digital still cameras, comprising:a first blade and a second blade, each having a plurality of arms pivotally mounted on a shutter base plate and at least one blade component pivotally supported thereby; a first-blade driving member constructed and arranged to be actuated by a biasing force of a first-blade driving spring to open an exposure aperture through said first blade in an exposure operation; a second-blade driving member constructed and arranged to be actuated by a biasing force of a second-blade driving spring to close said exposure aperture through said second blade in the exposure operation; a first-blade retaining member and a second-blade retaining member, constructed and arranged to retain, immediately before a start of the exposure operation, said first-blade driving member and said second-blade driving member at positions where to start the exposure operation and to release, upon the start of the exposure operation, retaining forces of said first-blade driving member and said second-blade driving member respectively, at a preset timing; and a cocking member having a first pressing portion and a second pressing portion, wherein, in a movement from an initial position toward a cocked position, said cocking member actuates, via said second pressing portion, said second-blade driving member against said biasing force of said second-blade driving spring to open said exposure aperture by said second blade while said first blade is kept withdrawn from said exposure aperture by said biasing force of said first-blade driving spring, said cocking member is stopped once at a temporary stop position where said exposure aperture is opened by said second blade, and said cocking member is then moved, in photographing, from said temporary stop position to said cocked position so that said first-blade driving member is actuated by said first pressing portion to close said exposure aperture via said first blade against said biasing force of said first-blade driving spring while said second blade is kept withdrawn from said exposure aperture by the second pressing member, and after said exposure aperture is closed by said first blade, said cocking member is restored to said initial position from said cocked position before the start of the exposure operation by said first-blade driving member and said second-blade driving member.