PROBLEM TO BE SOLVED: To provide a rotary drive mechanism for a light beam deflector with small size and with less failure and noise.SOLUTION: An eye refractive power measurement apparatus, which includes: a projection optical system that projects a measurement index on the fundus of an eye a receiving optical system that receives an index image formed by the reflection of the measurement index on the fundus of the eye and an eye refractive power measuring optical system that receives the index image to measure eye refractive power, includes a rotary drive unit, including: the light beam deflector that is disposed in the optical path of the eye refractive power measuring optical system and in a position that is out of the conjugate position of a pupil a rotor that is provided with the light beam deflector on an inner peripheral surface a stator that is provided through a bearing on the outer peripheral surface of the rotor and rotates the rotor around the optical axis of the optical measurement system a drive control means that continuously rotates the rotor in a certain direction with respect to the stator and a second magnet that attracts the rotor and the stator in an approaching direction to each other with respect to the direction of the optical axis when the rotor is rotated.COPYRIGHT: (C)2013,JPO&INPIT【課題】 小型で故障や騒音の少ない光束偏向部材の回転駆動機構となる。【解決手段】 被検眼眼底に測定指標を投光する投光光学系と、測定指標の眼底での反射により形成される指標像を受光する受光光学系と、その指標像を受光して眼屈折力を測定する眼屈折力測定光学系を有する眼屈折力測定装置において、眼屈折力測定光学系の光路に配置され、かつ瞳孔と共役位置から外れた位置に配置された光束偏向部材と、光束偏向部材が内周面に設けられた回転子と、回転子の外周面にベアリングを介して設けられ測定光学系の光軸を中心に回転子を回転させる固定子と、回転子を固定子に対して一定方向に連続的に回転させる駆動制御手段と、回転子の回転時において光軸方向に関して回転子と固定子が接近する方向に吸着させるための第2の磁石と、を備える回転駆動ユニットを備える。【選択図】 図5
