Under the U.S. Patent laws, claims must particularly point out and distinctly claim what the inventor understands her invention to be. Up until three years ago, the inquiry for determining indefiniteness was to ask whether claims were amendable to construction, or insolubly ambiguous. If the latter was true, then the claims were invalid as indefinite. But the Supreme Court weighed in on the standard in 2014, rejecting it. In order to provide clear notice of the boundaries of the claim, the correct inquiry was to ask whether—in view of the intrinsic record—one skilled in the art would understand the scope of the claims with “reasonable certainty.”
What are some lessons to take away from how the Nautilus standard has been applied?
First, subjective claim language should be viewed as a red flag.
In a case involving a patented bone fixation system, the claims required that one system component be of a “substantially different construction” than another. The limitation had been added during prosecution, to avoid the prior art. Years later, a defendant in a patent infringement suit attempted to initiate an inter partes review of the patent claims, only to have its petition denied. Why? Because the Patent Office was of the view that the limitation rendered the claims indefinite. In litigation, the patent holder proposed that the term “construction” referred to a component’s shape or structure, offering expert testimony that relied on a subset of the patent’s figures. Yet there was nothing in the patent to direct anyone to those figures in particular. Moreover, there was no teaching regarding the distinction between a “difference,” and a “substantial difference.” Thus, one of ordinary skill in the art would not know when components fell within the scope pf the claims.
Subjective terms are not always fatal though. In a case about biocompatible polymers, a disputed limitation related to an “observable change” to the polymer. Claims are not indefinite just because they require an observer to make a visual judgment. Here, the claim language itself explained that an “observable change” indicated crosslinking, and that the gel had reached a predetermined thickness. Dependent claims provided additional guidance by reciting specific examples of what type of an “observable change” must be visible. For example, the “observable change” should result in not being able to see a pattern in a substrate surface through the polymer, or in not being able to see a substrate at all. Though the phrase “observable change” did not appear in the specification, the patent set forth several examples of how to determine when a gel had achieved a predetermined thickness. Accordingly, one skilled in the art would have known what an “observable change” looked like, and when it had occurred.
Second, measurements can be tricky.
In a case about a multiple sclerosis therapy, manufacturing claims required that a co-polymer have a certain “molecular weight.” The trouble for the patent holder was that three different, chromatographic measurement methods would lead to three different molecular weights. A molecular weight measured by one method may fall within the claim scope, while that determined by the other two methods might not. The specification was not helpful, as it did not even acknowledge the different possible methodologies. Patentee’s expert admitted that there was no plain meaning in the field. And the patentee, itself, had adopted different meanings, at different times, during the prosecution of related patent applications.
Patent holders have faced similar difficulties in other cases such as Otsuka Pharm. Co. v. Torrent Pharm. Ltd. and Integra Lifesciences Corp., Integra Lifesciences Sales LLC, Confluent Surgical, Inc., and Incept LLC,. v. Hyperbranch Medical Technology, Inc. An expert in one case valiantly attempted to explain the meaning of “molecular weight” by reference to the Sigma Aldrich catalogue. It took him nine steps to get there, however, and none of the steps in his analysis appeared anywhere in the patent.
By contrast, claims directed to surgical shears were not indefinite, even though they recited clamping the arms of the shears to achieve a certain pressure measurement. Patentee’s expert had explained when the pressure measurement must be taken, and how the pressure should be measured. He had relied on basic mathematical and physics principals, tying their application to the patent specification.
Third, the Patent Office does not apply the Nautilus standard.
Rather, it asks whether a claim contains words or phrases, the meaning of which are unclear. The test is more stringent because an inventor may amend claims during prosecution (or during AIA proceedings). Accordingly, there is a lower tolerance for ambiguity. Consistent with the public notice function of patents, if an inventor can clarify claim language, she should do so.
