Patent ID: 8167507

Claim:
A focal plane shutter device comprising: a shutter base plate defining an opening; a front curtain configured to move between a first front curtain position in which the front curtain covers the opening and a second front curtain position in which the front curtain is moved away from the opening; a first urging member configured to apply an urging force to the front curtain to move the front curtain from the first front curtain position to the second front curtain position; a rear curtain configured to move between a first rear curtain position in which the rear curtain covers the opening and a second rear curtain position in which the rear curtain is moved away from the opening; a second urging member configured to apply an urging force to the rear curtain to move the rear curtain from the second rear curtain position to the first rear curtain position; and a charge mechanism configured to apply a first biasing force to resist the urging force of the first urging member and a second biasing force to resist the urging force of the second urging member, the first biasing force terminating at a different time than the second biasing force.