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. 08, 2014
Filed:
Jun. 02, 2010
Toon Hardeman, 's-Hertogenbosch, NL;
Toon Hardeman, 's-Hertogenbosch, NL;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
A method of determining a defect in a grid plate of an encoder-type position measurement system, the method including providing an encoder-type position measurement system to measure a position of a movable object with respect to another object, the encoder-type position measurement system including a grid plate and an encoder head, measuring a quantity of light reflected on each of the two or more detectors, using a combined light intensity of the reflected light on the two or more detectors to determine a reflectivity signal representative for the reflectivity of the grid plate at the measurement location, and determining a presence of a defect at the measurement location on the basis of the reflectivity signal of the grid plate.