Appeal No. 2003-1246
Application 08/393,617
attacks molybdenum" (Specification at 1, ll. 30-32). Appellants'
specification also mentions a number of U.S. patents which
disclose solder glasses that apparently do not require the use of
platinum. These patents include U.S. Patent 3,588,315, which
describes binary glasses such as antimony borate and ternary
glass compositions of antimony borate with the addition of small
amounts of molybdenum trioxide or tungsten trioxide, and
4,492,814; 4,521,641; and 4,493,944 (Snell et al.), which
disclose antimony borate systems which respectively also include
5% of BiO3, V2O3, and PbO and have melting points at about 350° C
(Specification at 1, l. 32 to p. 2, l. 4). The specification
then explains (at 2, ll. 6-8) that "[r]ecently, it has been
discovered that lamps which operate at higher wattages and which
have higher operating seal temperatures (i.e., above 400° C) have
not been adequately protected from moly-foil oxidation, resulting
in premature lamp failures."
Appellants' solution is a solder glass which comprises by
weight about 60 to 67% Sb2O3 (antimony trioxide), about 27 to 32%
B2O3 (boron trioxide), and from greater than 0 to 10% ZnO (zinc
oxide). The melting point ranges from 380° C to 466° C,
depending on the amount of ZnO, as shown in the graph in Figure 2
(Specification at 3, ll. 29-30). Because Appellants' solder
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