Patent ID: 9605949
Date: 2017-03-28
CPC Classifications: G01B,G01J

Claim:
1. A displacement sensor comprising: a light source unit configured to apply measuring light in a direction oblique to a surface including a measurement region of a planar measured object; a spectroscope configured to measure a spectral distribution of the measuring light reflected by the measurement region; a feature amount extracting module configured to extract a feature amount of the spectral distribution; and a displacement calculating module configured to calculate a displacement of the measurement region based on the extracted feature amount and a relation between the displacement and a feature amount acquired previously, wherein the light source unit includes a light source configured to emit light with a wavelength of a predetermined range, and an optical element in which a transmission wavelength or a reflection wavelength changes according to an incidence angle or an incidence position, wherein the measuring light is light whose wavelength changes according to an emission direction, which is generated by applying the light from the light source to the optical element obliquely at an angle where an optical axis of the light source is constant, wherein a wavelength distribution is generated on the surface including the measurement region by the measuring light so that the light reflected from the measurement region is changed according to the displacement of the planar measured object, and wherein the feature amount is a peak wavelength or a peak frequency of the spectral distribution.