PURPOSE: To measure displacement variables in a wide range accurately without influences of external disturbance such as temperature change by fitting one optical fiber for incident light and two optical fibers for detecting interference fringes to one end surface of a glass body.
CONSTITUTION: One incident optical fiber 22 and two interference fringe detecting optical fibers 23-1, 23-2 are fitted to one end surface 24 of the cylindrical glass body 21 so that respective end parts are oppositely fixed on the end surface 24. One the other hand, the opposite end surface 25 opposed to the end surface 24 to which the optical fibers are fitted is used as a reflecting surface for converting incident light into reference light. The opposite end surface 25 is oppositely arranged to a measured surface 26 of which displacement variable is to be measured. Thus, the displacement variables in a wide range can be accurately measured without influence such as temperature change.
OOUCHI CHIGUSA
ITOU SHIGENORI
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