| 摘要 |
PURPOSE:To simply attain detection with a high resolution by detecting a pattern of a monochromatic laser light beam reflected and diffracted by a diffracting plate which is stuck to a rotating body to be measured. CONSTITUTION:A diffracting plate 2 is stuck to one surface of a rotating body to be measured 1. This diffracting plate 2 is irradiated by a monochromatic laser light beam from a laser light source 3, and a reflected and diffracted pattern is detected by a photodetector 5 through a wavelength selecting filter 4. Subsequently, the output of the photodetector 5 is inputted to a flip-flop 7 and an integrator 9 through an amplifier 6, and their outputs are counted by a counter 8, and displayed by an analog indicator 10.
|
