NONCONTACT DISPLACEMENT GAGE

PURPOSE:To measure displacement with extremely high sensitivity by detecting a superconducting current generated in a 1st member made of a superconducting material with magnetic flux from the magnetic flux generation source of a 2nd member and finding the distance between both members. CONSTITUTION:The magnetic flux generation source 3 provided to the 2nd member 2 produces magnetic flux H to the 1st member 1 and a detection part 4 detects the superconducting current generated in the member 1 with the magnetic flux H and output a signal Y corresponding to the distance X. The superconducting current generated in the member 1 is a current I generated so as to produce magnetic flux in such a direction that the magnetic flux H from the generation source 3 is prevented from entering the member 1 by Meissner effect. Consequently, the magnetic flux H can be measured by detecting the current I, and consequently the signal corresponding to the distance X is obtained. The displacement of the movable part which is even of submicrons, i.e. the distance between the 1st and 2nd members can be measured.