Earlier this year, the US Court of Appeals for the Federal Circuit reversed a district court decision for relying on an incorrect standard for indefiniteness. (Nature Simulation Systems Inc. v. Autodesk, Inc). Now, in response to a motion for panel rehearing, the Federal Circuit modified its decision on rehearing deleting language. Nature Simulation Systems Inc. v. Autodesk, Inc., Case No. 20-2257 (Fed. Cir. Oct. 17, 2022) (Lourie, Dyk, Newman JJ.) (Dyk, J., dissenting)

Nature Simulations Systems asserted two patents against Autodesk (one a continuation-in-part of the other), both entitled “Method for Immediate Boolean Operations Using Geometric Facets.” According to the patents, the claimed methods are improvements upon a “Watson” method known in the prior art. The district court concluded that two terms—“searching neighboring triangles of the last triangle pair that holds the last intersection point” and “modified Watson method”—were invalid as indefinite based on “unanswered questions” regarding the scope of the claims posed by Autodesk’s expert. In the first reported decision, the Federal Circuit reversed. The Court held that the “unanswered questions” analysis used an incorrect legal standard, citing the specification as clarifying the scope of the claims and citing case law on deference to US Patent & Trademark Office examiners.

Following rehearing, the Federal Circuit slightly modified its decision in two primary ways but maintained its reversal of the district court’s ruling on indefiniteness.

First, the Federal Circuit added an explanation regarding how the specification answers the questions raised by Autodesk. The Court stated that “the language that the court stated ‘is not contained in the claim language’ is in the specification,” and cited a flowchart and accompanying description in the patent. The Court found fault in Autodesk’s argument because “[t]he claims set forth the metes and bounds of the invention; they are not intended to repeat the detailed operation of the method as described in the specification.”

Second, the Federal Circuit backed away from its previous reliance on deference to the examiner. In its earlier decision, the Court explained that the examiner had issued rejections for indefiniteness but withdrew them after amendments to the claims. The Court then spent a little over a page of the opinion explaining that, as official agency actors experienced in the technology and legal requirements for patentability, patent examiners are entitled to “appropriate deference.” Following rehearing, the Court removed the portion of the opinion addressing examiner deference entirely while maintaining the criticism that the district court gave “no weight to the prosecution history showing the resolution of indefiniteness by adding the designated technologic limitations to the claims.” In support, the Court cited cases holding that claims are construed in light of the specification and file history from the perspective of skilled artisans.

Judge Dyk again dissented, stating that “[t]he fact that a patent examiner introduced the indefinite language does not absolve the claims from the requirements of 35 U.S.C. § 112.” Judge Dyk argued that far from adopting a flawed “unanswered questions” analysis, the district court’s analysis was detailed and thorough and was properly performed in view of the specification. Judge Dyk found the majority’s definition of the disputed terms inconsistent with the claim itself because of differences between the claim and the disclosure in the specification. He argued that the portions of the specification cited by the majority did not address the claim limitations at issue (e.g., they did not explain what was meant by “modified Watson method” or the other limitations added in prosecution). In Judge Dyk’s view, it was only a declaration by Autodesk’s expert that raised the flawed “[c]laim language, standing alone” standard that the majority attributed to the district court—language not found in the district court’s decision.

Practice Note: This case no longer suggests that patent owners should review the file history because patent examiners may be entitled “appropriate deference.” Although the file history may still support patentability if the same invalidity argument had been raised and then withdrawn by the examiner, this case emphasizes that the specification may provide missing details not addressed by the claims.