A few new Federal Circuit opinions were released and designated as precedential, to cover the interpretation of terms in claims. This is somewhat surprising given the breadth of consistent case law on the issue, confirming that “[w]ords of a claim ‘are generally given their ordinary and customary meaning’ as understood by a person of ordinary skill in the art in question” in light of the specification, claims, and understanding of one of ordinary skill in the field. Indeed, these new cases- Kamstrup A/S v. Axioma Metering UAB and Sound View Innovations, LLC v. Hulu, LLC – do not affect this dogma. These cases do however, look into extrinsic evidence to resolve ambiguities in the claim language, including the prosecution history and specification. The Federal Circuit handled a very similar issue recently with Simo Holdings Inc. v. Hong Kong UCloudlink Network Technol. Ltd., where the Court analyzed claim limitation construction based on the specification.
Kamstrup involves a product-by-process claim covering a flow meter housing, and issues surrounding the functional and structural features imparted by that limitation, even if those features are not explicitly part of the claim. The Court began with the claim language, confirming the claim used product-by-process language, and then consulted the specification, the prosecution history, and any extrinsic evidence to help interpret the product-by-process limitation. It was ultimately determined that there was no information in the specification, prosecution history, or any other evidence that provided structural or functional features for that limitation. Further, the Court found portions of the specification, cited by the patentee, that purportedly provided additional practical limitations on the structure, were narrower than the claims and due to differences in scope failed to provide patentable scope to the limitation. Additional arguments by the patentee related to interpreting the structure were also disregarded for “read[ing] in a negative limitation that is at odds with the claim language” in one instance and lacking an identified portion of the specification in another instance.
Soundview reviewed claim language that was found to be ambiguous. The case involves data transmission, and focused on the meaning of concurrent buffering of data. The Court began with a review of the claim itself, noting that viewing the entire claim in context implicitly requires the same buffer be used. The Court next consulted the specification, noting that the specification does not describe using a separate buffer, while it does describe an embodiment using one buffer. The prosecution history was analyzed, where the limitation at issue was added in response to an anticipatory reference and to which the applicant argued the cited reference undertakes sequential buffering (clearing a buffer followed by filling it) and referencing the specification’s concurrent single buffer embodiment to support the new claim language. The Court found the statements made during prosecution, as well as the citation to the specification, would be interpreted by one of ordinary skill in the art to distinguish the cited reference from the application.
These cases illustrate the manner of claim construction- first analyzing the terms of the claims, in their entirety, followed by resolving ambiguity through looking to the specification and application prosecution, then extrinsic evidence. In Simo Holdings Inc., the specification was used to interpret claim terms, where the Court noted
we stated that “[w]e normally do not interpret claim terms in a way that excludes embodiments disclosed in the specification,” we explained the important qualifiers: “At leas[t] where claims can reasonably [be] interpreted to include a specific embodiment, it is incorrect to construe the claims to exclude that embodiment, absent probative evidence [to] the contrary.”
However, the Court noted that this does not mean all embodiments must be covered by a claim or that a preferred embodiment must be covered. The language of the claim controls, and a patentee can disclaim certain meanings or embodiments of the invention through sufficiently clear language in the claim.
The cases underscore the importance, first most of having clear language in the claims. However, the drafted claims can have ambiguity based on the circumstances, and arguments can always find ambiguity in some aspect of a claim. Second, the importance of the specification is also critically important. As noted by the Federal Circuit, the courts look first to the plain language of the claim, followed by the specification. Thus, having the appropriate embodiments in the specification are important to help inform on ambiguous language, as well as proper description of the features. Some applications overstate the features of an invention or embodiment, or in the instance of Simo Holdings Inc. understate the features, which can result in an interpretation of the claims that can result in an invalid patent under novelty or obviousness, or an unintendedly narrow patent that does not cover a competitor. Third, the arguments used during prosecution need to be carefully crafted, with the broadest statements of a cited reference addressed to ensure the courts do not interpret the application prosecution as disclaiming claim scope.