Patent ID: 6805500
Filing Date: 2004-10-19
Classification: G03B

Abstract:
A focal-plane shutter for digital still cameras, comprising:two base plates provided with a blade chamber between the two base plates, each having an aperture for exposure at about a center; a plurality of arms pivotally mounted to one of the two base plates; and a shutter blade group having at least one blade pivotally supported by a plurality of joint shanks with respect to the plurality of arms, placed in the blade chamber so that heads of the joint shanks project toward a photographer side, wherein the plurality of arms have a surface hardness of 500-600 Hv, wherein, of the two base plates, a base plate placed on the photographer side has at least one convex portion on an object-side surface thereof, the convex portion being plated with metal so as to have a surface hardness of 450-500 Hv and the arms come in slide contact with the convex portion and are shifted toward the object side immediately before each of the heads of the joint shanks, which had moved from inside the aperture, has reached a position at an edge of the aperture in an actuation of the shutter blade group.