Patent ID: 8061909

Claim:
A barrier device that is provided in front of an image pickup optical system to open and close an aperture of the image pickup optical system, comprising: a pair of principal blade members adapted to be arranged facing each other so as to be able to open and close; a plurality of pairs of auxiliary blade members adapted to be driven to open and close interlocked with open-close operations of said respective one pair of principal blade members; a barrier driving member adapted to rotate around an optical axis of the image pickup optical system in order to open and close said one pair of principal blade members; and a pair of barrier driving springs adapted to be disposed between said barrier driving member and said respective one pair of principal blade members, and to force said barrier driving member and said respective one pair of principal blade members to pull each other in a direction to close said principal blade members, wherein the open-close operations of said principal blade members are performed using spring forces of said barrier driving springs as said barrier driving member rotates.