PROBLEM TO BE SOLVED: To accurately stop and hold a mobile body at a plurality of positions without using a position detection sensor.SOLUTION: An SMA wire 52 is shrunken by energizing it, so that an operation lever 33a of a mobile lens frame 33 is moved in a direction to separate from a stopper 53. At the same time, an electromagnetic coil 77 is energized to move a positioning shaft 71 toward the operation lever 33a, so that the operation lever 33a of the mobile lens frame 33 is abutted against a tip of a positioning shaft 71 and held at a near point position. The SMA wire 52 is further shrunken, and at the same time the polarity of the energization current through the electromagnetic coil 77 is inverted and the positioning shaft 71 is sucked to make a super-near point position. The operation lever 33a of the mobile lens frame 33 is moved toward and held at the super-near point position. Thus, when the mobile lens frame 33 is moved in an optical axis direction, the mobile lens frame 33 can be accurately stopped and held at a plurality of positions without using a position detection sensor, thereby enabling the downsizing of the tip portion of an endoscope while suppressing the increase of the cost.COPYRIGHT: (C)2015,JPO&INPIT【課題】位置検出センサを用いることなく、複数の位置で正確に移動体を停止させて保持する。【解決手段】SMAワイヤ52に通電して収縮させ、移動レンズ枠33の操作桿部33aをストッパ53から離間する方向に移動させる。同時に、電磁コイル77に通電して位置決め軸71を操作桿部33aに向かって移動させ、移動レンズ枠33の操作桿部33aを位置決め軸71の先端に突き当て、近点位置に保持する。SMAワイヤ52を更に収縮させ、同時に電磁コイル77の通電電流の極性を反転させて位置決め軸71を吸引して超近点位置とすることで、移動レンズ枠33の操作桿部33aを超近点位置に移動させて保持する。これにより、移動レンズ枠33を光軸方向に移動させる際に、位置検出センサを用いることなく、複数の位置に正確に停止させて保持することができ、コスト上昇を抑制しつつ内視鏡先端部の小型化を図ることが可能となる。【選択図】図2
