Coaxial displacement sensor using a lateral shear interferometer with a phase grating

Abstract As a new non-contact method of measuring object displacement, a coaxial displacement sensor using a lateral shear interferometer with a phase grating is proposed. This proposed method uses a phase grating to generate fringes for the evaluation of displacement by means of spatial frequency analysis. Compared with triangulation-based displacement sensors which are widely used for industrial applications, this sensor makes stable measurement because there is no occlusion, and it has a simpler optical system than other non-contact optical methods. The steel pin gauge was measured by the triangulation-based displacement sensor and by the proposed method respectively, and the results confirmed that stable measurement was performed in any scanning orientation of the pin gauge in the proposed method.