Optics: measuring and testing – By polarized light examination – With light attenuation
Patent
1996-12-30
1998-11-10
Font, Frank G.
Optics: measuring and testing
By polarized light examination
With light attenuation
356390, 356237, 250237G, 25055939, 25055946, 364556, 364570, 382149, G01B 1130, G01B 1100, G01N 2100
Patent
active
058352236
ABSTRACT:
A system for measuring surface characteristics of an electronic interconnection component, such as a printed circuit board, by analyzing shadow moire patterns. Printed circuit boards are carried on a continuous conveyor under a grating. For each printed circuit board, a shadow moire fringe pattern is created in response to a determination that the printed circuit board is properly located under a grating and within the field of view of a camera. Fringes of the shadow moire fringe pattern are quantified over one or a multiple of analysis paths to determining if the printed circuit board is unacceptably warped, in which case a signal is generated. For each printed circuit board, multiple images can be captured and mathematically combined, by image subtraction, to produce an enhanced shadow moire fringe pattern that is analyzed for warpage.
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Chiu-Ching Tsang et al., "Real Time Measurement of Printed Wiring Board Flatness in a Simulated Manufacturing Environment," Believed to be known . . . by others within the meaning of 35 U.S.C. .sctn. 102 (a) before Dec. 30, 1996, Georgia Institute of Technology publication.
Brochure describing Series 800 System provided by Dickerson Vision Technologies of Atlanta, Georgia, Believed to be known . . . by others within the meaning of 35 U.S.C. .sctn. 102 (a) before Dec. 30, 1996.
Hassell Patrick B.
Zwemer Dirk A.
Electronic Packaging Services, Ltd.
Font Frank G.
Vierra-Eisenberg Jason D.
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