| 摘要 |
PURPOSE:To provide a compact and lightweight lens shifting device and enable gentle movement of a lens by providing a rotary feeding member to shift a lens frame along the optical axis of the lens, and by rotating the rotary feeding member stepwise by means of a piezoelectric element. CONSTITUTION:A lens holding frame 2 to hold a lens 1 is supported and guided by means of guide bars 3, 4. A screw of a sleeve 2a which is integrally formed with the lens holding frame 2 is engaged with a screw of the guide bar 3. A lamination type piezoelectric element 5 consists of a piezoelectric element of longitudinal effect type and a piezoelectric element of shear or transverse effect type, and arrangement is made so that the lamination type piezoelectric element may not be brought into contact with the guide bar 3 while it is not actuated. Application of the intermittent voltage to the piezoelectric element 5 allows the piezoelectric element 5 to be intermittently brought into contact against the external circumferential surface of the guide bar 3 which is also used as a feeding screw of the lens holding frame 2, resulting in rotation of the guide bar 3 and movement of the lens holding frame 2 stepwise. |
