Court Says Record More Important Than Dictionaries in Interpreting Patent Claims

Terms used in patents are more important in interpreting their scope than reliance on external sources such as dictionaries, the Federal Circuit Court of Appeals recently ruled in a highly anticipated en banc decision.

The court in Phillips v. AWH attempted to simplify patent interpretation by giving greater certainty to the boundaries of exclusivity granted in a patent. Impacting millions of issued patents in all areas of technology, the court introduced a standard methodology to interpret patent claims.

Ostensibly, the decision will enable businesses to more accurately determine both the value of their patents and their potential liability regarding patents of others. It also provides guidelines to patent applicants to ensure their inventive subject matter is adequately covered in their patent.

While the decision does not represent a substantial change in patent law, it does lessen the grey area of uncertainty in patents.

Scope of Patents

A patent is akin to a contract between an inventor and the government granting the inventor a limited monopoly to the invention. By statute, a patent must contain a specification, which describes the inventive subject matter.

The specification is further required to conclude with claims, which define the specific metes and bounds of the invention, i.e., describing what a patent owner is entitled to exclude others from making, using or selling. The claims give notice regarding what others are forbidden to make, use or sell.

The claims of a patent are somewhat analogous to the boundaries of property in real estate. While real estate boundaries may be precisely marked by cartographic means, the words of patent claims are often subject to many interpretations. Differing interpretations have great significance, such as between infringement and non-infringement of a patent.

The main issue in Phillips was whether the public notice function of patent claims is better served by referencing primarily sources external to the patent – such as general sources like dictionaries – or by looking primarily internally to the patentee’s use of the claim language in the specification.

The patent in Phillips concerns modular, steel-shell panels that can be welded together to form vandalism-resistant walls. The panels are useful in building prisons because they are load-bearing and impact-resistant. The claim language in dispute concerned certain support structures called “baffles,” and how they are oriented.

The defendant, AWH Corporation, sought a restrictive interpretation of this claim language based on the baffle orientations shown in the specification.

The patent claim record, primarily the patent specification, has long been recognized as the primary source of interpreting patent claims. But in 2002 the Federal Circuit created a competing canon of claim interpretation in Texas Digital Systems, Inc. v. Telegenix by placing greater emphasis on the dictionary definitions of claim terms, and assigning a less prominent role to the intrinsic evidence of the specification and the patent application’s file history with the patent office.

Look to ‘Intrinsic Evidence’

The Phillips decision, however, rejected the methodology used in Texas Digital, stating that it placed too much reliance on dictionary definitions, and too little reliance on intrinsic evidence. Applying their methodology to the claims in the Phillips patent, the court read the claims of the patent broadly, rejecting the restrictive interpretation proposed by AWH Corporation.

While the court in Phillips recognized the value of consulting dictionaries to ascertain the ordinary and accustomed meaning of a claim term, it disagreed with the Texas Digital claim interpretation approach, which advocated reading the intrinsic record only as a check on the dictionary meaning of a claim term.

Noting the expansive array of dictionary definitions, the court indicated that elevating the dictionary to such prominence focuses the inquiry on the abstract meaning of words rather than on the meaning of the claim terms within the context of the patent.

The Phillips decision also established a formula to interpret patent claims in due diligence proceedings so as to properly examine potential patent infringement. The formula starts by giving claim terms the ordinary and customary meaning that a person of “skill in the art” would understand that term to mean as of the filing date of the patent. The meaning of the claim term must be in viewed in the context of the entire patent, including the specification.

The inquiry could possibly end there if there is a widely accepted meaning of commonly understood words. If the meaning of the claim terms is still not readily apparent, however, the court would then look to the sources available to the public that show what a person of skill in the art would have understood the disputed claim language to mean.

The sources include, in order of importance:

• the words and context of the claims themselves;

• the remainder of the specification, which is noted as the single best guide to the meaning of a disputed term;

• the prosecution history of the patent;

• extrinsic evidence concerning relevant scientific principles, the meaning of technical terms, and the state of the art.

Implications of the Decision

By stating that a patentee’s own use of language is the single best guide to claim interpretation, the decision also underscored the importance of patent applicants expressly defining their claim terms in order to avoid future misinterpretations.

A patentee is permitted to be their own lexicographer, provided that the definition is not contrary to the commonly accepted meaning of the term.

Entities with substantial interest in building patent portfolios should implement policies to ensure that important claim terms are expressly defined in patent applications.

This gives business concerns more information regarding the value of patents, and thus provides for more informed decisions regarding licensing and enforcement of patent, as well as avoiding liability.

While the court recognized that there is no magic formula for conducting claim construction, and that a court is not barred from considering any particular sources or required to analyze sources in any specific sequence, the Phillips decision nonetheless provides the most comprehensive methodology of claim interpretation to date, and ensures the prominence of the patentee to use his or her own language to determine the meaning of patent claim language.