To satisfy the definiteness requirement of Section 112(b), the claims of a patent must particularly point out and distinctly claim the subject matter of the invention. 35 U.S.C. § 112(b) (a patent's “specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention”). Patent claims must “inform, with reasonable certainty, those skilled in the art about the scope of the invention.” Nautilus, 134 S. Ct. at 2124 (emphasis added). “The claims, when read in light of the specification and the prosecution history, must provide objective boundaries for those of skill in the art.” Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364, 1371 (Fed. Cir. 2014) (citing Nautilus, 134 S. Ct. at 2130).

In Niazi Licensing Corp. v. St. Jude Med. S.C., Inc., No. 21-1864 (Fed. Cir. Apr. 11, 2022), the Court of Appeals for the Federal Circuit considered whether the relative claim terms “resilient” and “pliable” were indefinite or not.

The asserted patent, U.S. Patent No. 6,638,268 (“the `268 patent”), was directed to a double catheter used to cannulate the coronary sinus. An excerpt from a representative patent claim (with the words “resilient” and “pliable” emphasized) is reproduced below:

1. 1. A double catheter, comprising:

an outer, resilient catheter having shape memory and a hook shaped distal end configured for cannulation of the coronary sinus with at least one curved bend;

an inner, pliable catheter slidably disposed in the outer catheter and of greater length than the outer catheter so that a distal end portion of the inner catheter can be extended or retracted from a distal end opening of the outer catheter to vary the overall length of the double catheter . . . .

The district court had held that the claim terms “resilient” and “pliable” were indefinite; but the Federal Circuit disagreed, finding the terms broad but not uncertain.

With regards to the term “resilient,” other claim language such as “shape memory,” “sufficient stiffness,” and other resilient materials also described in the specification, was found to provide guidance such that “a person of ordinary skill reading the claims and written description would know of exemplary materials that can be used to make a resilient outer catheter, i.e., one that has shape memory and stiffness such that it can return to its original shape.”

The Federal Circuit also found guidance in the patent specification's examples of a “pliable” inner catheter (such as a “soft material such as silicone” and “explaining that the inner catheter is more flexible than the outer”).

A skilled artisan, viewing the written description as a whole, could readily differentiate between a “resilient” outer catheter and a “pliable” inner catheter. And, as explained above, the written description provides objective boundaries for determining whether a catheter is “resilient” or “pliable.”

The Federal Circuit cited Sonix Technologies Co. v. Publ'ns Int'l, Ltd., 844 F.3d 1370 (Fed. Cir. 2017) and Enzo Biochem, Inc. v. Applera Corp., 599 F.3d 1325 (Fed. Cir. 2010) in support of this intrinsic evidence approach. The Federal Circuit also relied on the extrinsic evidence of dictionary definitions to “confirm that the terms ‘resilient' and ‘pliable' would have had broad but understood meanings to a skilled artisan.”

Because using words of degree may raise questions of indefiniteness, having a detailed explanation with examples in the specification can provide guidance in construing such relative terms in a patent claim with “reasonable certainty.” Relative terms or adjectives also may be described in connection with an objective functional outcome. In evaluating the use of a relative term in a patent claim, one should consider whether that relative term is as definite as the art permits.

The attorneys at Thomas P. Howard, LLC are experienced in prosecuting and litigating patents nationwide including in Colorado.