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:
Nov. 14, 1995
Filed:
Mar. 23, 1994
Christopher G Brickell, Mukilteo, WA (US);
Kenneth A Langland, Seattle, WA (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
The positions of objects in a holder, such as a cassette containing semiconductor wafers, are determined by a system that projects a pair of coplanar light beams through the cassette from one side. A reflector on the opposite side reflects both light beams back though the cassette and onto separate photodetectors on the one side. A computer analyzes signals from the photodetectors as the cassette is moved through the light beams. As the cassette moves the light beams are interrupted by the wafers. The relative widths and timing of pulses in the signals indicate the location of wafers in the cassette and whether a wafer is misaligned.