The Federal Circuit reversed a district court’s decision finding that claims of a computer-aid-design (CAD) patent indefinite under 35 U.S.C. § 112(b).

The patent was an improvement to a known Boolean operation for analyzing and representing three-dimensional geometric shapes (“the Watson method”). The patent boasted that its “modified Watson method” provides simplicity and flexibility compared with prior methods and is easier to program and implement.

The claim was directed to a “method that performs immediate Boolean operations using geometric facets of geometric objects” and recited steps including “searching neighboring triangles of the last triangle pair that holds the last intersection point” and “splitting each triangle through which an intersection line passes using modified Watson method.”

Interestingly, the examiner at the U.S. Patent and Trademark Office (PTO) had flagged the claim for indefiniteness during prosecution and accepted an amendment of the claim that addressed the examiner’s concerns. Faced with this history, the district court saw the question as:  “if the PTO issues a patent after amendment to clarify an indefinite term, but an expert later opines that a [person having ordinary skill in the art] POSITA would not understand the term, how does the Court determine whether the term is indefinite? The only way to do so here is to look at each argument [presented by the patent challenger] to see if [the patent challenger] raises any unanswered questions.” The district court also felt that the answers to the questions must be found “in the claims,” notwithstanding that the question could be answered by reading the specification of the patent.

The majority of the panel, in an opinion authored by Judge Newman and joined by Judge Lourie, found that the district court committed legal error in framing the inquiry as whether a patent challenger could raise “unanswered questions” regarding the patent claim. The Federal Circuit instructed that “[c]laim language, standing alone” was not the proper way to resolve questions of indefiniteness. Instead, “[p]atent claims are viewed and understood in light of the specification, the prosecution history, and other relevant evidence, as would have allowed a skilled artisan to know the scope of the claimed invention with reasonable certainty.” Using this framework, the Federal Circuit found answers to the questions raised by the patent challenger in the specification. Also, the Federal Circuit criticized the district court's failure to address the prosecution history concerning the amendment of the claim to overcome indefiniteness, stating that “[a]ctions by PTO examiners are entitled to appropriate deference as official agency actions, for the examiners are deemed to be experienced in the relevant technology as well as the statutory requirements for patentability.”

Judge Dyk dissented. He felt that the district court performed the correct legal analysis and stated that the “fact that a patent examiner introduced the indefinite language does not absolve the claims from the requirements of 35 U.S.C. § 112.”