Patent ID: 6513390
Filing Date: 2003-02-04
Classification: G01B,G01L

Abstract:
A temperature insensitive strain sensor, comprising:a strain-sensitive material adapted to be physically contacted to a surface of a workpiece; means for illuminating said strain-sensitive material with a beam of linearly polarized light at a selected polarization direction relative to strain-induced fast and slow orthogonal axes in said strain-sensitive material, said beam of linearly polarized light being substantially perpendicular to the surface of the workpiece; and detection means positioned with respect to the workpiece for measuring an intensity of at least one of a first polarization component that is parallel to said selected polarization direction and a second polarization component that is perpendicular to said selected polarization direction of said beam of linearly polarized light making at least one pass through said strain-sensitive material and processing means connected to said detection means for calculating from said intensity a difference between strains along the strain-induced fast and slow orthogonal axes in said strain-sensitive material, said difference being substantially independent of fluctuations in ambient temperature.