Appeal 2007-0128
Reexamination Control 90/006,208
Patent 5,573,648
metals or metal oxides. Additionally, one of ordinary skill in the art would have
been motivated to form electrodes having the claimed percentages of carbon black
and platinum with a tetrafluoroethylene copolymer as Grot, Uchida and
Vanderborgh all teach that such electrodes are known in the art to generate
electrical current in the presence of gaseous reactions and as Grot and Uchida
explicitly identify their electrodes as suitable for use in gas sensing applications.
Claim 6
Atwood claim 6 depends from claim 1 and further requires that the gas
sensor membrane be composed of a solid, perfluorinated ion-exchange polymer.
(Appeal Br., p. 68, claim 6). Atwood argues that no combination of the cited
references teaches or suggests the gas sensor of claim 6.
Atwood=s argument is not well understood. Dempsey specifically states
that perfluorocarbon sulfonic acid membranes are the preferred solid polymer
electrolyte ion-exchange membrane material. (Dempsey, col. 6, ll. 45-62).
Dempsey states that the perfluorocarbon sulfonic acid membranes provide
excellent ion exchange capacity, are highly stable, and have excellent thermal
stability. (Id.). Dempsey’s preferred perfluorocarbon membrane is a hydrated
copolymer of
polytetrafluoroethylene (PTFE) and polysulfonyl fluoride vinyl ether containing
pendant sulfonic acid groups sold under the NAFION trade designation. (Id. at
col. 6, line 66 to col. 7, line 16).
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