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:
Sep. 11, 2001
Filed:
Apr. 30, 1999
Paul Dutta-Choudhury, Franklin, MA (US);
Len Picard, Newtonville, MA (US);
Yasunari Tosa, Arlington, MA (US);
Cognex Corporation, Natick, MA (US);
Abstract
Methods and apparatuses are disclosed for defining a locus of viable points on an elongated object, such as a locus of viable bond points on a lead of a lead frame. The locus guides the bond point positioning of a wire bonder so that the number of unacceptable wire bonds is reduced. The locus is a region adapted to receive a bond, and is defined such that for any bond centered therein, the probability of forming an unacceptable bond is reduced by offsetting the locus from at least a portion of the lead edge(s) by a minimum-offset distance. The minimum-offset distance is based on various factor(s), such as user tolerance and bond width. Further, the definition of the locus is independent of lead shape, and consequently works with a variety of lead shapes. The locus can also have various shapes for a single lead, and the shapes can vary depending on the application. The method and apparatus herein disclosed describe a variety of methods to detect the leads and define the size, position, and shape of the locus during training. Preferably, the lead tip is also detected so that the locus can be defined based on an offset from the front of the lead. During operation, characteristics of the locus and/or the target bond point are used to relocate the lead and refine the target bond/point before bonding. Alternative embodiments disclosed include inspecting the leads.