Patent ID: 7182530
Filing Date: 2007-02-27
Classification: G03B

Abstract:
1. A shutter device comprising: a stationary plate including a plurality of driving electrodes arranged at intervals; a movable element opposing the stationary plate and including a sheet subjected to an electret-forming process for maintaining the sheet in a permanently electrically polarized state to hold constant charges; and a drive control unit configured to move the movable element using variation in electrostatic force, thereby shielding light, the electrostatic force being generated between the constant charges and charges generated in each of the driving electrodes when a voltage is applied to each driving electrode, the generated electrostatic force being varied by varying the voltage applied to each driving electrode, wherein the driving electrodes are arranged on the stationary plate with a first pitch in a start area ranging from a position at which the movable element starts to move, to a predetermined position, and a second pitch wider than the first pitch in an area other than the start area.