Measurement of Microdeformation by Transparent-Type Diffraction Moire Interferometry Using Light Control Plate

Abstract

Moire interferometry is a method of measuring submicron displacement distribution using two or four collimated beams incident to a specimen diffraction grating. In this paper, in order to form these two or four beams, a transparent diffraction grating is used. Two types of transparent diffraction moire interferometry are developed. One uses oblique incident beams for measuring one-dimensional displacement. The other uses normal incident beams for measuring one- or two-dimensional displacement components. In the latter, the 0th-order diffraction beam is noise. This noise is removed using light control plates which were developed recently. By using this diffraction moire interferometry, a compact system for microdeformation measurement is developed.