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:
Jul. 30, 1996
Filed:
Jul. 15, 1994
Carl T Ito, Scottsdale, AZ (US);
Other;
Abstract
A solder ball placement system incorporating a placement head moveable vertically toward and away from a solder ball shuttle having a plurality of solder balls positioned thereon. A corresponding plurality of pickup tubes extend from the placement head and are connected to a vacuum source for attracting and holding a corresponding solder ball. The pickup tubes are mounted for limited vertical movement with respect to the placement head to allow the individual pickup tubes to extend into the placement head varying distances to accommodate for uneven placement of solder balls such as warpage of a workpiece or shuttle. The respective pickup tubes each incorporate a collar abutting against a vibrator plate that is actuated by an ejector solenoid when the vacuum is released and the solder balls are to be placed on a workpiece. A ball sensing system incorporates a diode array having temperature sensitive PN junctions which are subjected to a heat source on one side and the cooling effect of ambient air traveling through pickup tubes on the other side. Sampling of the voltage drop across the respective diodes presents an indication of the presence or absence of solder balls on the respective pickup tubes.