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:
Oct. 29, 1996
Filed:
Apr. 19, 1995
Louis J Stans, Setauket, NY (US);
Christopher F Lynch, White Plains, NY (US);
Photocircuits Corporation, Glen Cove, NY (US);
Abstract
The apparatus and method operate by first generating a set of amplitudes for a constant current pulse. Each amplitude in the set is associated with one conductor on the reference printed circuit board and represents the amplitude which generates a determined voltage rise in that one conductor that is within a set range of a desired voltage rise for that one conductor. Each determined voltage rise representing the difference between a first voltage drop reading and a subsequent voltage drop reading taken across each conductor while the constant current pulse is applied. Once the set of amplitudes is generated, the apparatus and method generate a set of test voltage rises. Each test voltage rise is associated with one conductor on the test printed circuit board and represents the difference between the first and the subsequent voltage drop readings taken across that one conductor when the constant current pulse with the amplitude from the set of amplitudes for the corresponding conductor on the reference printed circuit board is applied to that one conductor. Once the test voltage rises are generated, then the apparatus and method compare the test voltage rise for each conductor on the test printed circuit board against the desired voltage rise for the corresponding conductor on the reference printed circuit board to determine if the test voltage rise exceeds the desired voltage rise. If the test voltage rise exceeds the desired voltage rise, then the apparatus and method identity the conductor as defective. The test apparatus and method may multiply each reference voltage rise in the set of reference voltage rises by a set factor to establish a table of adjusted reference voltage rises and then use the adjusted set of reference voltage rises when comparing and evaluating the test voltage rises.