| 摘要 |
PURPOSE:To curtail remarkably the number of parts without requiring a complicated driving force transfer mechanism such as a gear, a pulley, a wire, etc., by using a linear motor as a driving source for moving a lens. CONSTITUTION:Feed is executed to a coil 52 of an electromagnet 5 which has been provided in the inside of a needle 2, a moving magnetic field is formed, it is operated on a stator 3, and between the stator and a needle 8, a resiliency is generated. The respective magnetic pole tooth 31 and 51 of the stator 3 and the electromagnet 5 are formed by shifting a pitch, and by selecting successively and energizing coil, the resiliency can be used as a thrust of one direction. By controlling a voltage and a frequency of electric power supplied to the electromagnet 5, magnitude of the thrust can be controlled, and this thrust is transferred directly to a lens body 1a as a driving force, and can be moved to a position corresponding to a set converting magnification. In this way, a complicated driving force transfer means is not required for moving a lens, and also the device can be constituted of a single linear motor, therefore, the curtailment of the number of parts and the reduction of cost can be realized.
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