Patent ID: 8325348
Filing Date: 2012-12-04
Classification: G01B

Abstract:
1. A laser interferometer system for measuring roll angle of linear displacement, the laser interferometer system comprising: a laser source to produce: a mirror assembly, disposed at one side of the wedge prism assembly; an optical interferometry assembly, disposed between another side of said wedge prism assembly and the laser source; a phase detection assembly to: said optical interferometry assembly being to: the wedge prism assembly and the mirror assembly being to: said optical interferometry assembly being further to: the wedge prism assembly and the mirror assembly being further to: cause the fifth beam and the sixth beam to return back to said optical interferometry assembly along the second path, said optical interferometry assembly being further to: the third beam, the fourth beam, the fifth beam, and the sixth beam being incident on said wedge prism assembly to cause incident points of the third beam, the fourth beam, the fifth beam, and the sixth beam, to comprise four apexes of a square, spots of said third beam and the fifth beam, passing through the wedge prism assembly, being located at a diagonally arranged pair of the four apexes, and spots of said fourth beam and the sixth beam, passing through the wedge prism assembly, being located at another diagonally arranged pair of the four apexes, where said optical interferometry assembly comprises a polarizing beam splitting prism, a first quarter-wave plate, a second quarter-wave plate, and a corner cube, where the polarizing beam splitting prism being opposite to the laser source, the first quarter-wave plate being positioned between the corner cube and the polarizing beam splitting prism, the second quarter-wave plate being positioned between the polarizing beam splitting prism and the wedge prism assembly, the first quarter-wave plate and the second quarter-wave plate being in parallel with a first face and a second face of the polarizing beam splitting prism, respectively, the corner cube having an axis perpendicular to the first face, where the polarizing beam splitting prism is further to: where the seventh beam and the eighth beam exit the polarizing beam splitting prism via a fourth face of the polarizing beam splitting prism, where the seventh and eight beam pass through the second quarter-wave plate and exit the second quarter-wave plate, where, when exiting the second quarter-wave plate, the seventh beam and the eighth beam correspond to the third beam and the fourth beam, where the third beam and the fourth: where the polarizing beam splitting prism is further to: where the emitted ninth beam is to travel through the first quarter-wave plate, where, when exiting the first quarter-wave plate, the ninth beam corresponds to a tenth beam being in parallel with but at a different height from the ninth beam, where the tenth beam: where the eleventh beam and the twelfth beam are in parallel, but orthogonal, with each other and exit the polarizing beam splitting prism via the second face of the polarizing beam splitting prism, where the eleventh and twelfth beam pass through the second quarter-wave plate, where, when exiting the second quarter-wave plate, the eleventh beam and the twelfth beam correspond to said fifth beam and the sixth beam, where the fifth beam and the sixth beam: where the treatment of the fifth beam and the sixth beam within the polarizing beam splitting prism, combines the fifth beam and the sixth beam to form the second beam, and where the second beam exits the polarizing beam splitting prism via the third face of the polarizing beam splitting prism.