Appeal 2007-0128
Reexamination Control 90/006,208
Patent 5,573,648
Claim 13
Atwood claim 13 depends from claim 1 and requires that the diameter of the
sensing and counter electrodes be about 10 mm and that the protonic conductive
electrolyte membrane have a thickness of about 0.17 mm.
As to the dimensions of the membrane, the Examiner states that it would
have been obvious to utilize a membrane having the particular size as Dempsey
teaches a membrane having a size of 0.3 mm and one skilled in the art would
recognize that a thinner membrane provides for reduced internal resistance.
Atwood disagrees with the Examiner that finding the optimal membrane thickness
requires only routine skill in the art. According to Atwood, Dempsey fails to
provide an explanation of the “numerous considerations” that would have to be
taken into account to optimize the membrane thickness.
Dempsey teaches that the purpose of the membrane is to separate the sensing
and counter electrodes and allow for the passage of positively charged ions while
rejecting the passage of negatively charged ions. (Dempsey, col. 6, ll. 45-51).
While Atwood claims a membrane thickness of 0.17 mm, Dempsey Example 4
employs describes a cell membrane formed from 0.3 mm thick NAFION ®. Grot
however, teaches that its electrodes provide superior properties as compared to
those described in Dempsey. Grot further teaches that the thickness of the
membrane typically ranges from 25 to 175 microns, i.e., .025 to .175 mm, a range
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