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:
Apr. 28, 1992
Filed:
Jul. 16, 1990
Dana H Brown, Rochester, MN (US);
Timothy J Chainer, Mahopac, NY (US);
Wayne J Sohn, Teaneck, NJ (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A laser (10) provides an output beam to an interferometer (12). A portion of the output beam is directed by a beamsplitter to a receiver (18) as a reference beam while the remaining portion of the output beam passes through the beamsplitter and impinges on a plane mirror reflective surface (14a) mounted upon or integrally formed with or upon a surface of a body of interest, such as rotary actuator or arm (14). The arm has a fixed center of rotation O and rotates through an angular range indicated by theta-max. Phi is the angle of incidence of the laser beam with the arm in its original position when theta equals zero. .vertline.OC.vertline. and .vertline.CD.vertline. are distances which locate the intersection point between the arm and the laser beam relative to the center of rotation O when theta equals zero. A corner cube (16) is located at a convergence plane and returns all reflected beams back to the plane mirror and hence to the receiver via the interferometer. The interferometer and receiver operate to provide a determination of the position of the arm relative to a reference position, the determined position being used to cause a servo track or tracks to be written upon a medium at a desired position.