| 摘要 |
PURPOSE:To change the quantity of electricity supplied to a generating element and to maintain the sensitivity of detection constant by providing a feedback circuit from the output of a displacement output circuit connected to the output of a responding element to the power supply part for the generating element and controlling the power supply part. CONSTITUTION:A displacement detecting part 10 is so arranged as to move relatively with an object to be detected. The part 10 consists of a beam generating element, a beam responding element and a holed plate. These elements are so constituted as to face a light emitting element 2, a photodetector 4 and a holed plate 9. A feedback circuit 13 is provided from the output of a displacement output circuit 5 to the power feed part 12 of the element 2. The average value components -DC components in the displacement displaying signal are integrated by the integrator 18 by the circuit 13 and the conductivity of the part 15 is decreased by the value corresponding to the integrated value. Thus the quantity of electricity supplied to the generating element is changed and the sensitivity of detection is made constant. |
