| 摘要 |
PURPOSE:To enable a stable detection for a long time with limited transmission loss of light signals by providing a condenser lens facing a plurality of discs having equi-space grooves on the circumference thereof. CONSTITUTION:Equi-space grooves are provided on the circumferences of discs 2a and 2b firmly mounted at both ends of a rotating shaft system 1 and lens systems 6a and 6d at ends of optical fibers 3a, 3b and 3c at the position facing the grooves. The lens systems 6a and 6b and the lens systems 6c and 6d are shifted only by about 1/4 pitch circumferentially with respect to the projections of the discs and a pulse signal from a light source unit 4b is detected with a vibration detector 5b as electrical signal proportional to the relative torsion angle between the discs 2a and 2b. In this manner, a condenser lens system is provided at an open section of a fiber to produce a pulse light thereby simplifying the detection circuit with limited transmission loss of light signals and thus, a stable detection can be done free from effect of the intensity of light. |
