Skip to main content
Find a Lawyer

Determining the Scope of an Invention as Written in Patent Claims: FindLaw Interview with Byron W. Cooper of Townsend and Townsend and Crew LLP

The most significant issue facing judges, lawyers and litigants in patent cases is how to determine the scope of an invention as written in the patent's claims. Patent claims can be analogized to the metes and bounds description of real property. But while the scope of real property can be determined by careful surveys, placement of fences and now, global positioning technology, inventions protected by patents are defined simply by words and words often have multiple meanings. The slightest difference in meaning in a patent's claims may determine whether or not a patent is infringed and thereby whether the owner of the patent may exclude the infringer from using the technology or obtain millions or hundreds of millions of dollars in royalties. The Federal Circuit, charged with the responsibility of interpreting patent law has had to struggle to find an objective system or procedure for construing patent claims. In fact, the question of where to look for the definition of a patent claim's terms -- dictionaries or the patent itself -- has plagued the Federal Circuit since the Court's inception in 1982.

FL: What are the competing theories of claim construction that the Federal Circuit will resolve in this case and the rationale behind them?

By agreeing to hear the Phillips v. AWH case en banc, the Federal Circuit will try to strike a balance between two fundamental, yet fundamentally opposing canons of claim construction. The first canon, articulated in Markman v. Westview Instruments, 52 F.3d 967 (1995) and Vitronics v. Conceptronic, 90 F3d. 1576 (1996) requires that patent claims be construed in light of the claims themselves, the specification, and the prosecution history (the intrinsic record). The rationale for construing claim language in the context of the intrinsic record is that it allows competitors and others in the relevant industry to determine the scope of a patent with reasonable certainty and thus serves a public "notice function."

The second canon of claim construction, found in Texas Digital v. Telegenix, 308 F.3d 1193 (2002) is that limitations may not be imported into a patent's claims from the specification. The rationale behind this second canon is that a patent's claims should be allowed their full scope and should not be limited by the patent's written description. To that end, claim terms should be construed based on their "ordinary" meaning, as they are generally used in dictionaries and treatises.

FL: How has this apparent conflict affected the patent application process?

Competing claim construction theories invite inefficiencies in the patent application process. Patent applicants can not be sure how their claims will be interpreted in future litigation during the life of the patents. Applicants can attempt to remove some ambiguity by explicitly defining terms in the claims of their applications. However, defining every term in the claims of a patent would be impractical, inefficient, and ill-advised since it may lead to narrow claims as explicit definitions in the specification may further limit, rather than expand the scope of the claims.

Uncertainty over what is the proper process for claim construction can lead some applicants to use alternate terms in varying the claims to cover every possible combination or variation. This ambiguity in the claim construction process invites both more variation in claim drafting, and more applications as applicants seek to ensure protection regardless of which competing claim construction theory is ultimately used by the courts.

FL: How has this apparent conflict affected the litigation of patent claims?

The conflict over whether and when dictionaries or the intrinsic record should be consulted to construe a patent's claim term has created confusion among lawyers and district court judges. While the Federal Circuit was established to create consistency in the patent law, different panels of the Federal Circuit have drafted divergent opinions using different approaches to claim construction. The ambiguity created by these opinions has contributed to a reversal rate of nearly 50% of all district court claim construction rulings. The inconsistency in the law insures that almost every case is litigated to the appellate level because often both sides can find ample support for their desired claim constructions. Any district court choosing one approach can only guess at which Federal Circuit panel will hear the dispute and which methodology that panel will use to decide the issues. The result is that neither the courts nor litigants have a predictable method of resolving the disputes before them, which increases the cost and duration of patent litigation. If the Federal Circuit clarifies and coordinates the two competing claim construction canons, providing an objective system or procedure for construing patent claims, it would be easier for litigators to advise their clients and for district court judges to rule with confidence in these matters.

FL: Given the current ambiguity, what should a current patent applicant do to insure that their patents will be interpreted or construed to the degree that they want?

Applicants are always advised to draft applications with claims of different types (method, apparatus, means-plus-function) and scope to insure adequate coverage of the invention and to avoid the prior art. The goal is to seek protection of one's invention by drafting claims that are ultimately construed as valid over the prior art yet have sufficient scope to fully protect the invention from future infringement. Claim interpretation has always been uncertain to some degree. In the past some have complained that means-plus-function claims were construed differently than they are construed by courts today. A good patent application will always contain claims of different types and scope so that no matter how the patent law evolves in the future it will not affect all of the claims.

FL: How do you think the Federal Circuit will rule in this case?

Given the fact-specific nature of claim construction and the range of panel opinions, the Federal Circuit will most likely attempt to structure a uniform approach which strikes a balance between making sure that patents serve their public notice function and making sure patents cover the breadth of invention intended by the inventor. Without dismissing one source or another as irrelevant, hopefully the Federal Circuit will provide judges, lawyers and litigants with the guidance they need to properly evaluate what claim terms mean. In that regard, the Federal Circuit may return to the type of analysis it first considered in Markman, emphasizing the need to first look at the claims themselves, in the context of the specification and the prosecution history and to consider dictionaries and treatises when the intrinsic record is not clear.

Was this helpful?

Response sent, thank you

Copied to clipboard