Patent attributes
A displacement gauge comprises an objective lens 15 that projects light onto a measurement subject 16, an exciting portion that vibrates the objective lens 15 at a preset amplitude along an optical axis direction of light passing through the objective lens 15, a position detector for detecting the position of the objective lens 15, an objective lens scan portion 52 for scanning the objective lens 15 along a plane orthogonal to the optical axis direction, an objective lens movement detecting portion 53 for detecting the moved position of the objective lens 15, an operation processing portion 58 for calculating a distribution of displacement amount within a measuring area, based on the positional information of the objective lens 15 within the measuring area detected by the objective lens movement detecting portion 53, and the displacement amounts measured at plural measuring points, and an output portion 66 for outputting the result of calculation by the operation processing portion 58.
