| 摘要 |
PURPOSE: To eliminate the necessity of a mechanical vibration system without influence of the disturbance of a commercial frequency to a measurement signal by providing a polarizer, a stepping motor for driving to vibrate the polarizer, and control means for reciprocating the motor. CONSTITUTION: A polarizer 30 is rotated by a stepping motor 48 until a vane 42 is just introduced into a light barrier 40 so that a reference position sensor 44 responds. Then, this position is reversely rotated by the number of stationary steps by a stepping motor. The position thus obtained is specified as the zero point position of a rotor 12. The rotor (not shown) is periodically rotated from the zero point position to the right and left under the suitable control of the motor 48. The frequency of the rotating motion is remarkably different from the commercial frequency, and the polarizer 30 or hence the polarized surface of a measured optical beam 45 is rotated corresponding to the rotation of the rotor. |
