Earlier this month, the Patent Trial and Appeal Board (PTAB) of the U.S. Patent and Trademark Office (USPTO) changed a number of decisions to "informative" status.  An informative decision reflects "the Board's general consensus on recurring issues and guidance to examiners, appellants, patent owners, or petitioners in areas where parties routinely misapply the law" (see PTAB's Designations for Opinions)

One of these opinions is Ex Parte Jung, initially published in March of last year.  In it, the PTAB clarifies how a certain commonly-used claiming technique could be construed as either in the conjunctive or disjunctive depending on the disclosure of the specification.  While this interpretation is not new and dates back to a 2004 Federal Circuit opinion, many practitioners still use similar language in claims with the intent for these claims to be interpreted in the disjunctive only.  Therefore, it is worth revisiting this case.

The relevant sections of a representative claim recite (formatted for clarity and with emphasis added):

    receiving, by the control point, one or more scene objects comprising the scene to be played back from the media server in response to the request, each scene object including metadata representing at least one of
        a precedence relation indicating the scene object's location in a sequence of scene objects and
        a connection relation indicating one or more scene objects capable of replacing the scene object, the connection relation including at least one of
            a connection branch and
            a contents connection list having a first group identification...

This claim was rejected as obvious over a combination of two references.  The Applicant took the position that the first reference failed to teach what the Examiner relied upon it for, a "connection relation including at least one of a connection branch and a contents connection list."  The Applicant further took the position that the second reference also failed to teach that feature, as well as "at least one of a precedence relation indicating the scene object's location in a sequence of scene objects and a connection relation indicating one or more scene objects."

Getting straight to the point, the PTAB stated that the plain meaning of claim language in the form of "at least one of A and B" is conjunctive and such language should be interpreted as "at least one of A and at least one of B."  This interpretation was set forth by the Federal Circuit in SuperGuide Corp. v. DirecTV Enters., Inc., and is based on the principle (from Strunk and White's Elements of Style) that "an article of a preposition applying to all the members of the series must either be used only before the first term or else be repeated before each term."

Such a construction, however, does not apply when "the patent's claims, specification, or prosecution history necessitate a broader meaning."  Thus, in some situations, "at least one of A and B" is properly construed in the disjunctive as "at least one of A or B."  For example, if the specification suggests that only one of A or B is to be selected, then the disjunctive interpretation should be applied.

In the case at hand, the Examiner interpreted the first instance of "at least one" in the claim as referring to either a precedence relation or a connection relation.  But the Examiner did not support this interpretation with any reasoning.  Thus, the PTAB instead applied plain and ordinary meaning per SuperGuide to find that this term should have been interpreted as conjunctive.  The PTAB wrote: "like any claim construction straying from the ordinary meaning, the Examiner should set forth the reasoning for such an interpretation, including citations and explanations of relevant portions of the claims, specification, or prosecution history."  Furthermore, the PTAB's analysis of the specification resulted in a conclusion that while both a conjunctive and disjunctive interpretation was supported therein, there was no "clear definition or disavowal which would compel a disjunctive construction."

Regarding the second instance of "at least one" in the claim, the PTAB found support for a disjunctive interpretation.  But, it stated that "neither the claims nor the remainder of the Specification ever suggest that a connection branch and a contents connection list must be mutually exclusive . . . [t]hus, nothing compels interpreting 'and' to mean 'or' contrary to its ordinary meaning."

Therefore, both instances of "at least one" were properly construed as conjunctive.  As a result, the PTAB reversed the Examiner's obviousness rejections, as the PTAB's claim construction was sufficiently narrower than that of the Examiner to avoid reading on the cited references.  The irony here, however, is that the narrower construction of "at least one of a connection branch and a contents connection list" was not adequately supported by the specification.  Consequently, the claims were rejected under 35 U.S.C. § 112, first paragraph for lack of written description.

The practice tip here is that a claim term in the form of "at least one of A and B" will be interpreted in the conjunctive unless the Applicant clearly requires a disjunctive interpretation.  Nonetheless, numerous practitioners are unaware of SuperGuide and still expect such a term to mean "A or B."  A safe bet for those who wish to claim in the conjunctive or disjunctive is to use "A and B" or "A or B", respectively.  With appropriate support in the specification, of course.

Ex parte Dong (PTAB 2018)
Panel: Administrative Patent Judges MacDonald, Horner, and Engle
Decision on Appeal by Administrative Patent Judge MacDonald