US Patent 7978220 Optical apparatus having device for removing foreign substance

An optical apparatus includes a rectangular optical member provided on an optical axis, a supporting member configured to support the optical member, and a rectangular vibrating device stuck to the optical member close to and in parallel with one of four sides of the optical member and configured to vibrate the optical member in a wave fashion having a predetermined wavelength to have a plurality of nodes parallel with the one side. A support position at which the optical member is supported by the supporting member at a side opposite the one side of the optical member is located inward from the opposite side by ¼ the predetermined wavelength.