MEASUREMENT OF MICRODEFORMATION BY TRANSPARENT-TYPE DIFFRACTION MOIREINTERFEROMETRY USING LIGHT CONTROL PLATE

Moire interferometry is a method of measuring submicron displacement d istribution 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 transp arent 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 displ acement components. In the latter, the 0th-order diffraction beam is n oise. This noise is removed using light control plates which were deve loped recently. By using this diffraction moire interferometry, a comp act system for microdeformation measurement is developed.