| 摘要 |
PURPOSE:To realize an actuator for optical disk which is simple in structure, excellent in mass-productivity, and inexpensive, by driving the condenser lens in a prescribed direction by piezoelectric element. CONSTITUTION:A lens frame3 and movable piece 4, which hold a condenser 2, are coupled with each other by two piezo-electric elements 1 and 1' having a strip-like bimorph structure. When a voltage is impressed across the piezo- electric elements 1 and 1', the lens 2 moves in the direction normal to the signal pit row on a disk. A piezo-electric element 15 having a bimorph structure is composed of an outer ring part 15a, inner ring part 15b, and pieces 15c, 15c', and 15c'' connecting the ring parts 15a and 15b, and the piezo-electric elements 1 and 1' are coupled with the inner ring part 15b through a movable piece 18 and the outer ring part 15a is fixed to a box body 17. When a voltage is impressed across the piezo-electric elements 1 and 1', the inner ring part 15b moves in the direction F and, therefore, the lens 2 also moves in the same direction. |
