Patent ID: 7187451

Claim:
A two-dimensional displacement measuring apparatus adapted to measure a two-dimensional displacement, comprising: a two-dimensional diffraction unit; a laser light source for providing an incident light; a beam splitter for separating said incident light into at least two beams to be incident on said two-dimensional diffraction unit so as to generate a plurality of first diffracted beams and a plurality of second-order diffracted beams from the first diffraction of said beams; a plurality of conjugate optical lenses for reflecting said first diffracted beams respectively so that said first diffracted beams return to said two-dimensional diffraction unit to generate a plurality of second diffracted beams where said second diffracted beams and said second-order diffracted beams generated as a result of the first diffraction of said beams stagger; and a plurality of interference optical dephasing modules for receiving said second diffracted beams respectively so as to separate each of said second diffracted beams into at least two signal beams by which a two-dimensional displacement is measured.