Not Always Obvious to Optimize Claimed Variables

Examiners commonly rely upon optimization to support their conclusions of obviousness. The CAFC has recognized that “[t]he normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.” In re Peterson, 315 F.3d 1325, 1330, 65 USPQ2d 1379, 1382-83 (Fed. Cir. 2003). However, a particular parameter must first be recognized as a result-effective variable, i.e., a variable which achieves a recognized result, before the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977).

A recent BPAI decision in Ex parte Collison (Appeal 2010-002734, in application serial no. 11/284,178, decision issued February 29, 2012) illustrates deficiencies to look for when evaluating an obviousness rejection supported by an optimization rational.

The claim at issue in Ex parte Collison described a floor structure made of a wood laminate that included “a single polyethylene layer vapor barrier having a thickness of between 0.5 to about 1.0 mil.” The Examiner cited several references in an obviousness rejection, which disclose: “a weakness of laminate flooring is moisture resistance and high sound transmission due to foot traffic;” a rubber buffering sheet used in wood flooring; “rubber and polyethylene are equivalent materials known in the vapor barrier art;” and examples of “polyethylene foam or rubber foam having a thickness of [59 to about 275 mils]” that provides “improved soundproofing and excellent waterproofing.” The Examiner agreed that the cited references fail to disclose a “vapor barrier having a thickness of between 0.5 to about 1.0 mil.” The Examiner reasoned that it would have been obvious to modify the prior art vapor barrier to have a thickness inside the claimed range because discovering the optimum or workable ranges involves only routing skill in the art.

The Board reversed the Examiner’s obviousness rejection. The Board stated “the Examiner has not established that a polyethylene layer having a thickness between about 0.5 to about 1.0 mil was recognized to be a result-effective variable as a vapor barrier” (emphasis added). While the prior art taught a polyethylene foam layer that provides improved soundproofing and excellent waterproofing (as noted above), the prior art reference only disclosed that the polyethylene foam layer was tested for soundproofing, and not for their properties as a vapor barrier. The Board concluded that the prior art

does not disclose a minimum dimension of thickness for the [polyethylene foam layer] that is sufficient to perform both soundproofing and waterproofing, or reasoning for significantly lowering thickness of the [polyethylene foam layer] to about 1 mil. More importantly, it is simply unknown whether a floor structure having the claimed vapor barrier would result from combining and optimizing teachings and variables of the references.

Lessons learned from Ex parte Collison are that optimization is not a per se rule, and that the cited prior art needs to evidence that the variable was recognized to be a result-effective variable for the claimed purpose. In Ex parte Collison, recognition of being a result-effective variable for soundproofing was not applicable to being a vapor barrier.