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. 17, 2001
Filed:
Jul. 09, 1999
Robert Innes, Berkeley, CA (US);
William A. Eckes, Castro Valley, CA (US);
Etec Systems, Inc., Hayward, CA (US);
Abstract
A laser beam or other parallel light beam divides at a beamsplitter into sample and reference beams. The sample beam reflects from a reflective surface back to the beamsplitter, and the reference beam reflects from a retroreflector back to the beamsplitter. The beams are then directed into a telescope. The angle between sample and reference beams at the telescope is proportional to the angle between the laser beam and the normal to the reflective surface. The telescope collects both sample beam and reference beam and transforms each beam into a sharply defined point image. The lateral separation between the two point images is proportional to the magnification of the telescope and to the angle formed at the telescope between the sample beam and the reference beam. If the reflective surface is accurately aligned relative to the laser beam, then the two point images are substantially superposed on one another. Alignment is performed by adjusting the orientation of the reflective surface, until the lateral separation between the two point images reaches zero or a predetermined value.