The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 18, 1982
Filed:
May. 14, 1979
Ruediger F Rauskolb, Palo Alto, CA (US);
Optimetrix Corporation, Mountain View, CA (US);
Abstract
A pair of position control circuits is employed for controlling the position of an interferometrically controlled stage along orthogonal X and Y axes of motion of the stage. Each of these position control circuits is provided with a variable phase shifter responsive to a reference signal and a control signal for producing an output signal of the same frequency as the reference signal but shifted in phase as determined by the control signal, and with a phase detector responsive to the output signal from the variable phase shifter and to a measurement signal obtained from the interferometrically controlled stage for producing a position control signal proportional to the difference in phase between those signals. The sum and the difference of the position control signals of selected phase produced by these position control circuits are employed to extend the resolution of the position control circuits.