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.

Keywords

• Phase grating
• Lateral shear interferometer
• Displacement sensor