Patent ID: 7753602
Filing Date: 2010-07-13
Classification: G03B

Abstract:
1. A lens barrel comprising: a barrier blade configured to open and close over a photographic aperture; a barrier drive member configured to move between a closing position for causing said barrier blade to close the photographic aperture and an opening position for causing said barrier blade to open the photographic aperture, thereby driving said barrier blade between a standby position for covering the photographic aperture and an image-taking position for opening the photographic aperture; and a barrier drive spring, an amount of a charged spring force of which varies in accordance with the opening/closing operation of said barrier blade, wherein, as said barrier drive member moves from the closing position to the opening position to cause said barrier blade to perform an opening operation, the amount of the charged spring force of said barrier drive spring progressively decreases, wherein as said barrier drive member is moved to the closing position, in a state in which said barrier blade is constrained from moving toward the closing position, the amount of the charged spring force of said barrier drive spring progressively increases in accordance with the movement of said barrier drive member, wherein as said barrier blade is caused to perform the opening operation, in a state in which said barrier drive member is constrained from moving in a direction causing said barrier blade to move toward the opening position, the amount of the charged spring force of said barrier drive spring progressively increases in accordance with the opening operation of said barrier blade, and wherein said barrier drive spring is implemented by a tension coil spring, and said barrier drive member moves between the closing position and the opening operation by rotation, and causes said barrier blade to perform opening and closing operations by being brought into contact with said barrier blade during the rotation to cause said barrier blade to rotate in accordance with the rotation.