Patent ID: 7367722

Claim:
A shutter device comprising: a first shutter unit including a first stationary plate with a plurality of driving electrodes arranged with a first predetermined pitch, and a first movable element opposing the first stationary plate, the first movable element including a sheet subjected to an electret-forming process; and a second shutter unit including a second stationary plate with a plurality of driving electrodes arranged with a second predetermined pitch, and a second movable element opposing the second stationary plate, the second movable element including a sheet subjected to an electret-forming process, and wherein the plurality of driving electrodes arranged with the first and second predetermined pitches are arranged on the first and second stationary plates with a first pitch in a start area ranging from a position at which the first and second moveable elements start to move, to a predetermined position, and with a second pitch in an area other than the start area; and a pitch of the first pitch interval in the start area is narrower than a pitch of the second pitch interval which is in an area other than the start area.