Watch Your Language! PTAB De-Designates Previously “Informative” Opinion on Claim Construction
The Patent Trial and Appeal Board recently designated a new group of opinions “informative.” In addition to precedential (i.e., binding decisions that the Board must follow) and nonprecedential (i.e., nonbinding decisions that may carry some persuasive weight, but the Board is not required to follow) decisions, the Board’s third category of informative decisions represent opinions that the Board is not required to follow even though their persuasive value may be greater than that of a nonprecedential decision.
In Ex parte Jung et al., No. 2016-008290, 2017 Pat App. LEXIS 2490 (P.T.A.B. March 22, 2017), the Board interpreted the claim language “at least one of [A] and [B],” which was used several times in the claims on appeal. The Board acknowledged that this phrasing was susceptible to multiple interpretations: (1) the narrower “at least one of A and at least one of B” and (2) the broader “at least one of A or at least one of B.” It suggested that the claims themselves, the disclosure in the specification, and the prosecution history may illuminate which interpretation is appropriate for a given situation. Analyzing decisions from its controlling authority, the Federal Circuit, the Board held that the meaning of the phrase “at least one of [A] and [B]” must be presumed to be “at least one of A and at least one of B,” and the Examiner had not provided any rationale for applying the definition “at least one of A or at least one of B.” Looking to the specification, the Board found embodiments disclosed that had only one of the two relevant elements and embodiments that had both elements for some of the claim terms. For others, it found only embodiments having one of the two elements, and stated that the description did not suggest that the two elements were mutually exclusive. It held that the phrases in this appeal must be interpreted to mean “at least one of A and at least one of B.”
After imposing that interpretation, the Board issued a new ground of rejection. It concluded that the specification did not adequately support the claim language because the claims, as interpreted, required “at least one of A and at least one of B,” and for certain elements the specification only disclosed that A or B could be used.
The Board’s decision could be criticized for being circular; it notes that the claim language is susceptible to multiple interpretations, finds that the specification discloses embodiments supporting both interpretations for some elements and the broader interpretation for other elements, imposes the narrower interpretation in both situations, and concludes that the disclosure of alternatives is inadequate to support claiming their combination. It could also be criticized for not considering whether the claims could mean “at least one of A, at least one of B, or at least one of A and at least one of B.” Perhaps the claims should have been rejected as indefinite because they did not clearly and unambiguously specify what they did and did not cover. Regardless, this decision serves as a reminder to patent applicants, patent owners, and patent practitioners that claim language should be scrutinized and drafted carefully to ensure that the claims actually cover what they are intended to cover and that their terms are not susceptible to misinterpretation.
Edit: Since originally publishing this post, the Board stripped the “informative” designation from this opinion. Regardless of its status before the Board, it remains a good reminder that patent claims must be carefully drafted to ensure that they cannot be misconstrued.
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