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, 2015
Filed:
Jun. 30, 2011
Mingwu Bai, Blacksburg, VA (US);
Ming Chen, Blacksburg, VA (US);
Mingwu Bai, Blacksburg, VA (US);
Ming Chen, Blacksburg, VA (US);
Other;
Abstract
A plurality of laser positioning units are used to position an X-Y stage. In each laser positioning unit, a mirror constantly reflects laser beam to an optical position sensor, where the mirror is integrally mounted on a rotation unit which is integrally mounted on X-Y stage, where the laser diode is mounted on another rotation unit. Each rotation unit includes a fine rotation stage and a coarse rotation stage. When moving the X-Y stage, fine stages constantly rotate mirror or/and laser to reflect the laser beam onto the optical position sensor, the amount of rotations and geometry of position of laser and mirror gives precisely the position of moving stage. The fine stages and coarse stages in different laser positioning units work alternatively to position the stage, and the fine stages are calibrated if coarse stages moves.