| 摘要 |
PROBLEM TO BE SOLVED: To make a lens drive device compact by devising a space in which shape memory alloy wires are arranged. SOLUTION: First and second shape memory alloy members 31 and 32 are obtained by forming the shape memory alloy wires into coils. A lens guide rod 41 having a bearing part 45 thereon is inserted in the members 31 and 32 on both sides of it such that one end of each member is fixed to one end of a bearing part 56 and the other to a fixed cylinder. A groove row 42 is formed in the lens guide rod 41, and a plate spring 48 provided in the bearing part 45 is engaged with the groove row 42. When power is supplied to the first shape memory alloy member 32, it contracts as a result of its recovering displacement. The plate spring 48 elastically deforms by the force of the recovering displacement. Consequently, the V-shaped part 47 of the spring 48 moves over the projections of the groove row 42, so that a lens hold frame 44 moves to the image forming face side. When the supply of power is stopped, the first shape memory alloy member 31 returns to its original length as a result of its restoring displacement. However, since the V-shaped part 47 is engaged with a recess of the groove row 42, the restoring displacement is blocked and the lens hold frame 44 is locked in the position. COPYRIGHT: (C)2007,JPO&INPIT
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