Appeal 2007-1798
Application 10/347,666
(id.)
We agree with the Examiner that the discovery of an optimum value
of a result effective variable is within the skill of the art. In re Boesch, 617
F.2d 272, 276, 205 USPQ 215, 219 (CCPA 1980). As Appellants explain,
silicates have been used in the art for aluminium anodization (Specification
5: ¶ 00013). In addition, Appellants explain that
[s]ilicates are known to react with the surface of the aluminum.
Due to the local gradient effects in the vicinity of the
liquid/aluminium interface the pH decreases. The gradient
caused by a lower pH causes high inconsistent doping of the
surface since the silicates become increasing[ly] more insoluble
as pH decreases. The inconsistent doping is manifest in
unpredictable changes in the eventual capacitor. Sodium
silicate is typically used at a pH of approximately 10.5 to
reduce the occurrence of premature precipitation.
(id.) As Appellants explain “[t]he skilled artisan has therefore been limited
to the use of silicates, at a high pH wherein high uncontrollable silicate
incorporation occurs. . . .” (Specification 5: ¶ 00014).
Accordingly, we agree with the Examiner that a person of ordinary
skill in the art would have recognized that when silicates are used to coat
aluminum, the pH of an electrolyte composition is a results effective
variable. If the pH of the composition is too low, the silicates will become
insoluble. If the pH of the composition is too high uncontrollable silicate
incorporation occurs. Therefore, we agree with the Examiner’s assertion
that a person of ordinary skill in the art would have found it prima facie
obvious to optimize the pH of the electrolyte composition.
In sum, we find that the Examiner’s evidence and reasoning supports
a prima facie case of obviousness. Accordingly, the burden of coming
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