Metal fusion bonding – Process – Metal to nonmetal with separate metallic filler
Reexamination Certificate
1999-07-01
2001-07-03
Ryan, Patrick (Department: 1725)
Metal fusion bonding
Process
Metal to nonmetal with separate metallic filler
C420S555000
Reexamination Certificate
active
06253988
ABSTRACT:
BACKGROUND
Windshields and rear windows of vehicles such as automobiles often include electrical devices located within or on the glass. Typically, the electrical devices are antennas or defrosters. In order to provide an electrical connection to such an electrical device, a small area of metallic coating is applied to the glass which is electrically connected to the electrical device. An electrical connector for connecting to a lead or the lead itself is then soldered to the metallic coating on the glass. The solder typically used has a melting point of about 193° C. (380° F.) and requires about 750-800 watt seconds of energy to melt the solder. Heat of this magnitude flows to the glass and often damages the glass in regions near the solder joint, for example, causing cracking.
SUMMARY OF THE INVENTION
The present invention is directed to a solder composition that has a considerably lower melting temperature than solder compositions currently available for soldering to glass. As a result, when the present invention solder composition is employed for soldering components onto a windshield or rear window, the amount of heat that flows to the glass is low enough so that the glass experiences little or no damage. The solder composition of the present invention has a mixture of elements including indium, tin and silver. Less than about 75% of the solder composition by weight is tin.
In preferred embodiments, more than about 25% of the solder composition by weight is indium. More typically, less then about 50% of the composition by weight is tin and more than about 50% of the composition by weight is indium. The solder composition includes the element copper and preferably, the elements within the solder composition have a weight percentage of about 65% indium, about 30% tin, about 4.5% silver and about 0.5% copper. A preferred range of the weight percentage of the solder composition is 64.35%-65.65% indium, 29.7%-30.3% tin, 4.05%-4.95% silver and 0.25%-0.75% copper. The solder composition preferably contains no more than about 0.75% antimony, about 0.08% gold, about 0.2% lead, about 0.08% aluminum, about 0.03% arsenic, about 0.005% cadmium, about 0.005% zinc, about 0.25% bismuth, about 0.02% iron and about 0.005% nickel. The solder composition preferably has a liquidus of about 121° C. and a solidus of about 118° C.
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Antaya Technologies Corporation
Hamilton Brook Smith & Reynolds PC
Ryan Patrick
Stoner Kiley
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