The US Court of Appeals for the Federal Circuit affirmed an International Trade Commission decision finding a § 337 violation. The Court concluded that the Commission correctly found that an open-ended claim was enabled since there was an inherent upper limit and correctly construed the term “a” to mean “one or more” in finding infringement. FS.com Inc. v. International Trade Commission, Case No. 22-1228 (Fed. Cir. Apr. 20, 2023) (Moore, Prost, Hughes, JJ.)

Corning Optical Communications owns several patents directed to fiber optic technology. Corning alleged that FS violated § 337 by importing high-density fiber optic equipment that infringed the patents. In assessing infringement, the Commission construed the claim term “a front opening” to mean “an opening located in the front side of a fiber optic module (e.g., the opening depicted in Figure 13 of the [asserted] patent as having dimensions H1 and W1”) and further concluded that the term encompassed one or more openings. The Commission found that FS’s products met this requirement and therefore infringed. FS argued that certain claims were invalid because they were not enabled. The claims at issue recited “a fiber optic connection density of at least ninety-eight (98) fiber optic connections per U space” or “a fiber optic connection of at least one hundred forty-four (144) fiber optic connections per U space.” FS argued that these open-ended density ranges were not enabled because the specification only enabled up to 144 fiber optic connections per U space. The Commission rejected FS’s invalidity argument. FS appealed.

The Federal Circuit affirmed the Commission’s enablement determination. The Court explained that open-ended claims are not inherently improper and may be enabled “if there is an inherent, albeit not precisely known, upper limit and the specification enables one of skill in the art to approach that limit.” The Court found that there was an inherent upper limit of about 144 connections per U space since skilled artisans would have understood that densities substantially above 144 connections per U space were technologically infeasible. The Court further found that the specification disclosed that the maximum density achievable was 144 connections per U space and expert testimony confirmed that, despite market pressure, no commercial product has achieved a density greater than 144 connections. Considering this evidence, the Court concluded that the Commission properly found that the open-ended claims had an inherent upper limit of about 144 connections per U space and the claimed open-ended range was therefore enabled.

The Federal Circuit also affirmed the Commission’s infringement determination. The Court explained that the terms “a” or “an” in a patent claim generally mean “one or more,” unless the patentee evinces a clear intent to limit “a” or “an” to “one.” FS argued that the recitation of “front openings” in an unasserted claim showed a clear intent to limit “a front opening” in the asserted claim to a single opening. The Court rejected that argument, finding that limiting an unasserted claim to multiple openings did not show an intent to limit the asserted claim to one opening, particularly since the written description disclosed embodiments with one or more front openings. Thus, the Court found no reason to depart from the general rule that “a” front opening encompassed one or more openings.

Practice Note: Earlier this month, the Federal Circuit issued a decision in Salazar v. AT&T Mobility LLC et al., finding that while the claim term “a microprocessor” did not require that there be only one microprocessor, the subsequent limitations referring to “said microprocessor” required that at least one microprocessor be capable of performing each of the claimed functions. As a result, while the indefinite article “a” or “an” generally means “one or more,” subsequent limitations may require that a single component perform all the claimed functions.