| 摘要 |
PURPOSE:To prevent the mixing of electromagnetic noise, by fixing one of the polarizer and detector arranged in front of the light source in a dark box while making the other freely rotatable and photoelectrically converting the light signal guided from the detector to the outside of the dark box by an optical fiber. CONSTITUTION:The beam signal from the beam source 2 provided to the central part of one end of a sensor main body 1 is converted to parallel beam 3 which is, in turn, passed through the polarizer 5 fixed to the main body 1. The detector 6 provided in front of the polarizer 5 is suspended from the ceiling of the main body 1 in a freely revolvable manner and a buffer device is formed of a spring 7, a dash pot 8 and a wt. 9. In a usual state generating no vibration, the optical axis of the detector 6 is inclined by 45 deg. with respect to that of the polarizer 5. The beam passed through the detector 6 is converged to the input terminal of an optical fiber 11 by a lens 10 and guided to a beam receiving part 12 to be photoelectrically converted. Even when the polarizer 5 is made movable and the detector 6 is fixed, the same result is obtained. When the main body 1 is mounted to a vibration generating part, vibration is detected on the basis of the quantity of beam passing through the detector. By this method, an error due to electromagnetic noise is prevented.
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