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Claim Construction and Additional Limitations

The U.S. Court of Appeals (COA), in ABS Global, Inc. v. Cytonome/ST, LLC, No. 22-1761 (Fed. Cir. Oct. 19, 2023), reversed a Patent Trial and Appeal Board (Board) determination upholding the claims of U.S. Patent No. 10,583,439 titled “Hydrodynamic Focusing Apparatus and Methods.” In making this determination, the COA reversed the Board’s determination that a sample stream, as recited in independent claim 1, had a singular-only meaning, not allowing for a plurality of streams or a split stream.

In construing a sample stream as singular-only, the Board concluded that a plural-allowing scope would be inconsistent with dependent claim 2’s requirement that a focusing fluid be introduced into the flow channel symmetrically with respect to a centerline of the sample stream. In making this construction, the Board reasoned that only one centerline may exist on the substrate of the claimed device and that this centerline must lie within the sample fluid and not within a focusing fluid that has split the sample fluid. Moreover, the Board seems to have relied on the drawings that show only a single centerline for a pair of streams or the branches of a split stream.

In construing a sample stream as plural-allowing, the COA first notes that “at least in an open-ended ‘comprising’ claim, use of ‘a’ or ‘an’ before a noun naming an object” requires that the phrase be construed to “one or more unless the context sufficiently indicates otherwise.” LiteNetics, LLC v. Nu Tsai Capital LLC, 60 F.4th 1335, 1346 (Fed. Cir. 2023) at 1345; Salazar v. AT&T Mobility LLC, 64 F.4th 1311, 1315 (Fed. Cir. 2023) at 1315; Convolve, Inc. v. Compaq Computer Corp., 812 F.3d 1313, 1321 (Fed. Cir. 2016); Baldwin Graphic Systems, Inc. v.Siebert, Inc., 512 F.3d 1338, 1342–43 (Fed. Cir. 2008) at 1342–43. The COA further notes that this is the “general rule” and that an exception “only arises where the language of the claims themselves, the specifications, or the prosecution history necessitates a departure from the rule.” Baldwin, 512 F.3d at 1343.

Second, the COA notes that the specification states, “For purposes of the present disclosure, the term ‘a’ or ‘an’ entity refers to one or more of that entity. As such, the terms ‘a’ and ‘an’, ‘one or more’ and ‘at least one’ can be used interchangeably herein.” The COA further notes that “where the specification instructs as to the meaning of a claim term, the inventor’s lexicography governs.” Grace Instrument Industries, LLC v. Chandler Instruments Co., 57 F.4th 1001, 1010 (Fed. Cir. 2023) (quoting Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc)); see Thorner v. Sony Computer Entertainment America LLC, 669 F.3d 1362, 1365 (Fed. Cir. 2012); Martek Biosciences Corp. v. Nutrinova, Inc., 579 F.3d 1363, 1380 (Fed. Cir. 2009).

n view of these claim construction rules, the COA held that the specification did not supply “a clear and manifest disavowal” of the plural-allowing construction or totally negate it. Martek, 579 F.3d at 1380 and 1383. Specifically, the singular meaning is not demanded by the disclosed embodiments described solely as examples. Nor has it been shown an operational impossibility or something comparable that requires rejecting the plural-allowing meaning.

Accordingly, it is important not to read limitations into the claims which are not clearly and manifestly defined in the claims, specification, and drawings.


John Laurence TCP Law, Trademark Patent Copyright Lawyer

TCP Law focuses on helping individuals and businesses develop, secure, and enforce their intellectual property rights.

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