Salazar v. AT&T Mobility — Patents

Q: Does 'a' still mean 'one or more' in patent claims?

Yes. The Federal Circuit reaffirmed in Salazar v. AT&T Mobility that the indefinite article 'a' generally means 'one or more' in open-ended claims using 'comprising,' and that a later use of the definite article 'said' does not by itself change that general rule.

Q: So why did Salazar lose on claim construction?

Because the claim later referred to 'said microprocessor' performing several specific functions. The court held that 'said microprocessor' must refer back to the same one or more microprocessors introduced earlier, and that at least one single microprocessor must be capable of performing all of the recited functions, not different processors each doing one task.

The Federal Circuit reaffirmed that 'a microprocessor' can mean one or more, but held that 'said microprocessor' requires a single processor capable of performing every recited function.

A patent claim’s fate can turn on two of the smallest words in English. In Salazar v. AT&T Mobility LLC, 64 F.4th 1311 (Fed. Cir. 2023), decided April 5, 2023, the Federal Circuit confronted whether “a microprocessor,” later referenced as “said microprocessor,” required a single chip to perform every function the claim recited or allowed different processors to divide the work. Writing for a panel that included Judges Schall and Stark, Judge Stoll affirmed the district court’s construction and the resulting judgment of noninfringement: while “a” generally means “one or more,” the subsequent “said microprocessor” must refer to the same processor, and at least one microprocessor must be capable of performing all of the recited functions. The case is now a fixture in patent-drafting guidance.

At a glance

Case: Salazar v. AT&T Mobility LLC, No. 2021-2320, 64 F.4th 1311 (Fed. Cir. Apr. 5, 2023).
Court: U.S. Court of Appeals for the Federal Circuit; opinion by Judge Stoll, joined by Judges Schall and Stark.
Posture: Appeal from a judgment of noninfringement in the Eastern District of Texas, challenging the construction of “a microprocessor” / “said microprocessor.”
Holding: “A” means “one or more” in a comprising claim, and “said” does not alter that, but “said microprocessor” refers to the same one or more microprocessors, requiring at least one single microprocessor capable of performing all the recited functions.
Significance: Clarified the interplay between indefinite and definite articles and antecedent basis, with major implications for how functional claim elements are drafted.

Joe Salazar asserted U.S. Patent No. 5,802,467, directed to technology for two-way wireless and wired communication of sound, voice, and data, including command, control, and sensing functions. The claim at issue recited “a microprocessor” and then required “said microprocessor” to perform several distinct operations — generating, creating, and retrieving functions. The dispute was whether those functions could be parceled out among multiple microprocessors in an accused device, or whether one microprocessor had to be able to do them all.

”A” means one or more

Salazar’s central argument invoked a familiar canon. In open-ended claims using the transitional phrase “comprising,” the indefinite article “a” or “an” carries the meaning “one or more” unless the claim language, specification, or prosecution history evinces a clear intent to limit it to a single instance. On that point, the Federal Circuit agreed with Salazar. The court reaffirmed that “a microprocessor” does not mean exactly one microprocessor; it means one or more. It further confirmed that the later use of the definite article “said” does not, by itself, convert the earlier “a” into a singular requirement. So far, the canon favored the patentee.

That much of the opinion is unremarkable and consistent with decades of Federal Circuit precedent. The novelty lies in what the court did next with the antecedent-basis relationship between “a microprocessor” and “said microprocessor.”

The “said” twist and antecedent basis

The decisive move was the court’s treatment of “said microprocessor.” Because “said” refers back to its antecedent, the phrase “said microprocessor” must point to the same “one or more” microprocessors introduced earlier in the claim. Crucially, the court held that this antecedent relationship requires that at least one single microprocessor be capable of performing each of the recited functions. The claim did not permit different microprocessors to each perform only one of the generating, creating, and retrieving tasks; a single microprocessor had to be able to do all of them.

The court illustrated the point with a now-frequently-quoted analogy: “For a dog owner to have ‘a dog that rolls over and fetches sticks,’ it does not suffice that he have two dogs, each able to perform just one of the tasks.” In other words, “one or more” describes how many of the element may exist, but the functional limitations attach to a single instance that must satisfy all of them. The plurality permitted by “a” does not let the claim spread its required functions across separate components.

Why noninfringement followed

Under that construction, infringement required the accused devices to contain at least one microprocessor capable of performing all of the recited functions. Salazar had effectively argued for a reading in which any combination of processors, collectively performing the functions, would infringe. The court rejected that approach as inconsistent with the antecedent-basis logic of “said microprocessor.” Applying the proper construction, the Federal Circuit affirmed the judgment of noninfringement, conducting its claim construction review de novo and finding no error in the district court’s reasoning.

The result is a precise and somewhat counterintuitive lesson. The patentee won the abstract proposition — “a” means “one or more” — but lost the case, because the functional requirements tied to “said microprocessor” demanded a single component that could do everything. The decision underscores that the indefinite-article canon governs quantity, not the allocation of recited functions among components.

Open questions

How broadly does the antecedent rule reach? Salazar concerned “a”/“said” with stacked functional limitations; how the logic applies to other element types and claim formats will develop case by case.
Can careful drafting fully avoid the trap? The opinion implies separate recitation of components solves the problem, but real claims often must balance breadth against this constraint.
What about means-plus-function and system claims? The interaction of this construction principle with § 112(f) and multi-component system claims remains to be fully mapped.

Implications

Mind antecedent basis when stacking functions. Tying several functions to a single “said” element can require one component to perform them all, narrowing the claim.
“A” controls quantity, not allocation. “One or more” tells you how many of an element may exist; it does not let the recited functions be split across separate instances.
Recite components separately when needed. To let different parts perform different tasks, introduce and reference them as distinct claim elements.
Audit existing portfolios. Claims drafted with “a [component]” followed by “said [component]” performing multiple functions may be narrower than intended.
Construction can decide the case. Here a correct but narrow construction produced noninfringement, a reminder that claim language choices carry direct litigation consequences.

Frequently asked questions

Does “a” still mean “one or more” in patent claims? Yes. The Federal Circuit reaffirmed in Salazar v. AT&T Mobility that the indefinite article “a” generally means “one or more” in open-ended claims using “comprising,” and that a later use of the definite article “said” does not by itself change that general rule.

So why did Salazar lose on claim construction? Because the claim later referred to “said microprocessor” performing several specific functions. The court held that “said microprocessor” must refer back to the same one or more microprocessors introduced earlier, and that at least one single microprocessor must be capable of performing all of the recited functions, not different processors each doing one task.

What is the drafting lesson from Salazar? Be deliberate about antecedent basis. If you want different components to perform different functions, recite them separately rather than tying multiple functions back to a single “said” element. Using “a” plus “said” can require one component to do everything, narrowing the claim and creating noninfringement risk.