Digital Equipment Corporation

Sandia National Laboratories

Terri Giversen

Nile F Hartman

James L Jellison

Floyd M Hosking

Mark D Stratton

Jimmy R Reed

Bruce Short

Fred Yost

A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time.

Solderability test system

The present invention is a method and an apparatus for the precise quantitative measurement of the magnitude of force exerted at the points of contact on a high density electrical interconnect that quantitatively determines the magnitude of the force. The invention includes the steps of establishing a pressing relationship between a photoelastic material and the high density interconnect, coupling plane-polarized light into the photoelastic material stressed as a result of the pressing relationship with the high density interconnect, coupling of the polarized light being at 45 degrees with the direction of pressing, capturing an image of the fringe pattern of the plane polarized light exiting the stressed photoelastic material, the fringe pattern comprising of fringes wherein the number of fringes varies with the magnitude of the pressing force, and counting the number of fringes produced to determine the magnitude of force exerted on the photoelastic member.

Optical force sensor for high density planar electrical interconnects

Growing community of inventors

Beverly, MA, United States of America

Terri Giversen