Patent ID: 8075143

Claim:
A foreign substance removing apparatus for removing foreign substances adhered to a surface of a plate-like light transmitting member disposed in a light ray incident path, comprising: an electromechanical energy conversion element bonded to a first plane of said light transmitting member; an elastic member bonded to a second plane of said light transmitting member so as to face said electromechanical energy conversion element, the second plane being opposite from the first plane, said elastic member enabling a bending neutral surface to be maintained inside of said light transmitting member by compensating for an amount of increase in rigidity due to said electromechanical energy conversion element being bonded to said light transmitting member; and an AC voltage applying circuit for applying an AC voltage to said electromechanical energy conversion element to cause said light transmitting member to elastically vibrate in a direction perpendicular to the planes thereof, thereby removing the foreign substances adhered to the surface of said light transmitting member; wherein said elastic member has a thickness thereof made smaller than that of said electromechanical energy conversion element when said electromechanical energy conversion element has its Young's modulus smaller than that of said elastic member so that said elastic member enables the bending neutral surface to be maintained of said light transmitting member.