Patent ID: 8348526
Filing Date: 2013-01-08
Classification: G03B

Abstract:
1. A focal plane shutter device comprising: a shutter base plate defining an opening; a front curtain movably disposed between a first front curtain position to cover the opening and a second front curtain position to uncover 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 movably disposed between a first rear curtain position to cover the opening and a second rear curtain position to uncover 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 drive unit configured to apply a first biasing force to the first urging member to resist the urging force of the first urging member and apply a second biasing force to the second urging member to resist the urging force of the second urging member, the drive unit being further configured to hold the front curtain at the second front curtain position until application of the first biasing force to the first urging member has ended and hold the rear curtain at the first rear curtain position until application of the second biasing force to the second urging member has ended.