Ruling that patent claims must be read in the context of the written description and the prosecution history, the U.S. Court of Appeals for the Federal Circuit affirmed a construction which limited a claim term to embodiments described in the patent’s specification. RealSource, Inc. v. Best Buy Co., et al., Case No. 07-1387 (Fed. Cir., June 23, 2008) (Young, Distr. J., sitting by designation) (non-precedential).

This case arose from the plaintiff’s appeal of a lower court’s construction of the patent claim term “ID information,” which plaintiff conceded “was dispositive of [the plaintiff’s] entire [infringement] case.” Specifically, the plaintiff appealed the lower court’s construction that the claim term “ID information” means “encrypted data, not including the card number, stored on the debit card in the form of merchant ID, store ID, or terminal ID.”

The patent in suit is directed to “gift cards,” which are issued in lieu of paper gift certificates and permit a card holder to charge purchases against the amount on the card. The plaintiff conceded that under the lower court’s construction, the defendants’ debit cards did not infringe the “ID information” limitation because none of the defendants’ cards were encoded with a merchant ID, store ID or terminal ID. Indeed, the defendants’ cards only contained a card number, data that was explicitly excluded in the lower court’s construction of the term.

On appeal, the Federal Circuit refused the plaintiff’s invitation to adopt a plain meaning construction of the disputed term, ruling that claims must be read in the context of the written description and the prosecution history (not in a vacuum. The Court found that these two sources make clear that plaintiff did not “regard its invention” to encompass cards containing only a card number.

In the prosecution history, the claims originally recited “ID property” rather than “ID information,” but the plaintiff amended the claim after objection from the patent examiner that “property” did not adequately describe something that could be stored electronically. Based on this amendment and the history of it, the Court concluded that “ID property” (as used in the patent specification) and “ID information” (as used in the claims) were interchangeable. After reviewing the specification, the Court concluded that a card number and ID property are not the same and that “a person of ordinary skill in the art would have understood card number to be excluded from the definition of ‘ID information [stored on the debit card].’”

The Court dismissed the plaintiff’s additional argument that claim differentiation compels a broader reading of “ID information.” The plaintiff argued that certain dependent claims, particularly claim “ID information,” is “selected from a group consisting of merchant ID, terminal ID, and store ID.” Thus, the plaintiff argued that the independent claims must be construed to encompass a broader category of “ID information.” The Court rebuffed that contention, ruling that “[i]f a patent’s specification make clear the scope of the claim language, claim differentiation cannot be used to broaden the claim’s scope.” The Court reasoned that “[w]hile claim differentiation may suggest that merchant ID, store ID, and terminal ID are not the only pieces of information that may qualify as “ID information,” it does not mandate that any specific piece of information -such as the card number- be included in the definition of the term.”