Patent Claims Must Be, At Least, Reasonably Definite

By Barry R. Lewin

The claims of a patent define the scope of protection. But one issue that can be bothersome is how definite the claim language has to be.

First, the statutory language requires definiteness in claims. “The 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.” 35 U.S.C. § 112 ¶ 2 (emphasis added). This has been understood to mean that the claims must have language of definiteness. In Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120 (2014), the Supreme Court articulated a test for definiteness when it held “a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention”. (emphasis added). How does one definitively determine whether reasonable certainty exists? When is claim language reasonably certain and when does it not provide reasonable certainty? This can be a vexing question, and even in her opinion in Nautilus, Justice Ginsburg noted that there are language limitations which must be taken into account when determining definiteness. (Id. at 2129).

The claims of U.S. Patent No. 7,328,845 are directed to using a graphical indicator for encoding information on the surface of an object, where the graphical indicator is “visually negligible”. In Sonix Tech. v. Publications Int’l, (Fed. Cir. 2017), the challenger asserted that the term “visually negligible” was insufficient to meet the “reasonable certainty” standard and the claims were therefore invalid. In other words, the challenger argued that it was not possible to draw a bright line between when something is visually negligible or not and therefore the claims do not meet Justice Ginsburg’s test.

In the opinion, the Federal Circuit reviewed various cases to come up with a brighter line for reasonable certainty. First, the Court recognized that to determine reasonable certainty, like claim construction, one can look to the specification for guidance. The Court noted that when the specification provided no guidance or when the term in the claim is one of degree, the claim indeed may be indefinite. These situations were viewed by the Court as resulting in a subjective understanding of the term in the claim, which does not result in reasonable certainty.  In contrast, when the specification cites examples which can be used as guidance, as it apparently did in Sonix, that information may be used to determine the presence of reasonable certainty.

While a term like “visually negligible” might have been the best descriptor, it was still challenged as indefinite. What should an inventor do? As we have been advocating relative to overcoming Alice, a robust specification is a very good thing for putting your best foot forward. Specifications need to encompass examples and the examples need to be as narrowly defined as possible. It also is beneficial to write the claims with as definitive language as possible and also include specific examples as dependent claims. Of course, the specific examples can be written with ranges, which can also be relied on in the claims.