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:
Feb. 25, 2003
Filed:
Dec. 01, 1999
Bryan Kok Ann Ngoi, Singapore, SG;
Fan Hua, Singapore, SG;
Nanyang Technological University, Singapore, SG;
Abstract
A method and apparatus is disclosed for non-contact, on-line inspection of objects including a ball grid array package by means of a shadow moiré technique combined with a novel flash phase-shifting method. The grid pitch size, ball height, ball diameter, missing ball, coplananity can be determined or measured within several seconds. The apparatus includes a camera for viewing the object, a plurality of light sources arranged in a line for illuminating the object to be inspected, a frame grabber for capturing images of the object, an I/O adapter card for controlling the light sources and a personal computer for data processing. The individual components are integrated into system which provides a three dimensional map which is obtained quantitatively using a novel algorithm. The system can provide coplananity data, as well as data relating to grid pitch, ball height, ball diameter, and missing ball information.