| 摘要 |
PURPOSE:To detect the number of revolution of a rotating body surely by providing a part for absorbing light and a part for reflecting the same alternately on said body, and providing a detection part disposed with photodetector concentrically around a light emitting element. CONSTITUTION:Reflecting materials 1 are adhered at a specified interval to a rotating body A having no reflectivity and photodetector 3 are disposed concentrically around a light emitting element 2 so as to face oppositely to the reflection material. The light emitting from the element 2 is reflected by the material A and is detected with the photodetector 3. The number of revolution is detected with the photodetector, and further the direction where the body A causes a change in angle is measured in responding that which detector 3 detects the reflected light. The number of revolution is thus detected surely even if the body A causes oscillation, strain, uneven rotation, inclination, etc. |
