| 摘要 |
PURPOSE:To stably detect vibration even if an insulator as an object to be measured is rocking by overlapping a reflection light and a reference light while converging them at the same focus position and bringing a light interference signal detection surface near a focusing position. CONSTITUTION:A reflection laser beam R2 is applied while focusing on a detection surface 26 in an objective lens 16 and is reflected at a right angle by a second polarization beam splitter 12, thus reaching a first beam splitter 24. In the first beam splitter 24, the laser beam R2 is overlapped in the same space as a reference laser beam R3 which is focused by focusing on the same detection surface 26 as the laser beam R2, thus becoming an interference laser beam R4. The laser beam R4 is guided to a surface 26 for detection of a photo/electric converter 25 and is converted from light signal to electrical signal and further vibration is converted to speed by a demodulator 27. The vibration of an insulator body is measured by this measurement and a natural frequency of an insulator 3 is analyzed by a frequency analyzer 28. |
