Patent Infringement —
Effective Scientist /Attorney Teams
By Edward W. Funk, Ph.D.
The question of patent infringement usually begins with the business unit and moves to discussions with the patent attorney. It is then that the scientist/engineer as an expert witness becomes part of the team.
The initial focus is the claims. First, what are the claims’ advances over the prior art? Second, the claims must be compared to the potentially infringing product or process. A patent is said to be “literally infringed” if the claims exactly describe the potential infringing product or process. This is the simplest case and technical experts are of secondary importance
The complex technical and legal area is when the product/process does not exactly “read on” the claims. This introduces the concept of “Doctrine of Equivalents.” For the scientist/engineer, it can be confusing since it is not based on a clear statute but on a large literature of judicial decisions. Scientists like laws.
Also, the more expert the technical expert, the more he will see everything as an equivalent. But then this is probably not the “person of ordinary skill in the art.” The technical expert must step back and use a perspective in considering equivalents. This requires reasonable experience in patent cases.
Durham gives a good discussion of this doctrine for the scientist/engineer in “Patent Law Essentials.” It begins with the 1853 case of Winans v. Denmead on the coal-carrying railroad car and traces cases up to present high-technology cases. In general, scientists and engineers will interpret the doctrine as broader than patent attorneys, but can also point out critical differences in function, which can differentiate products or processes. As an example, most scientists would disagree with the court on Graver Tank v. Linde Air Products (1950) in that manganese is clearly not equivalent to the claims of an “alkaline earth metal.”
This area of “equivalence” is a key area where the input of a technical expert can be crucial. The expert needs to realize that he is a resource for explaining, defining and interpreting technical information for what will be a legal and not scientific decision. The scientist/engineer and attorney team works best when the technical expert understands his role in this interpretation of patent infringement decisions based on the doctrine of equivalents.
One important technical area is the determination of whether an improvement is still an equivalent. In fact, the improvement may even be patented. Does it add anything of significance to the invention? This is often an area for a technical expert.
While the technical expert should not become involved in case law, there are several recent famous cases known to every patent lawyer, which are helpful for the technical expert to understand his role. These are: Festo Corp. v. Shokestu Kinzoka Kogko Kabushiki and Warner Jenkinson, Inc. v. Hilton Davis Chemical Co.
Festo made big changes on the use of the prosecution history to argue equivalents. Before Festo, it was clear that a patentee could not recapture claim coverage, which was given up during prosecution. However, Festo made this far more exacting in that all equivalents were surrendered when the claim was amended. This “absolute bar” to equivalents has been recently overturned by the Supreme Court; this was important enough to generate numerous articles in “The New York Times,” “Wall Street Journal,” etc.
It does, however, affect the way technical experts and patent attorneys work together. The Warner-Jenkinson case (1997) laid out many of the crucial details of when and how prosecution history can be used to determine an equivalent. The case was a simple membrane filtration and the crucial issue was the pH range. Many chemists would find that the difference in pH used (5.0) by the infringer and the value in the claims (6.0) is scientifically trivial. However, the legal issue was viewed very differently, the result being that the burden is on the patent owner to rebut the presumption that the amendment was due to reasons of patentability.
After Festo, it is presumed that making a narrowing amendment to a claim creates the presumption that the ”Doctrine of Equivalents” cannot be applied. In the recent Supreme Court decision, it was held that making a narrowing amendment to a claim element creates the presumption that the “Doctrine of Equivalents” cannot be applied; this presumption can be rebutted with suitable arguments that the equivalent issue wasn’t, in fact, surrendered. The most likely argument will be that the equivalent was unforeseeable at the time of invention. Thus, it could not have been expected that the patentee could have drafted a claim literally encompassing the alleged equivalent.
However, the recent Supreme Court decision does still greatly restrict the arguments based on prior art when, for any reason, the claim has been narrowed. This limits the scientifically valid and strong arguments of the technical expert.
These decisions suggest the importance of having the patent attorney draft claims that do not need to be amended. This, in turn, requires a detailed evaluation of the prior art to draft strong claims, which are accepted without amendment. This, in light of Festo, gives a stronger patent against infringement. For example, the set of claims should be comprehensive enough to include many different features and components that are different from the prior art and which could be disputed as equivalents. The Supreme Court stated “the patentee, as the author of the claim language, may be expected to draft claims encompassing readily known equivalents.”
The Festo decision also suggests that patent attorneys structure “means plus function” claims. This requires that the specification provide multiple alternatives of the means and a careful discussion of equivalents. This benefits from input of the inventor and possibly other technical experts in the field. One needs to broadly define potential equivalents in the specification
The role of the technical expert can be also be essential in areas of rapid technological change. For the expert witness, a summary of the Texas Instruments v. U.S. Int’l Trade Comm’n (1988) is useful background. The technical expert has knowledge of the art “at the time of the infringement” and whether that technology would have been imagined or visualized by the patentee.
This chapter concludes with an example of how the expert witness can be valuable in reviewing the patent prosecution history. First, the expert can put in clear terms what scientific evidence was presented to the patent examiner to obtain certain claims. Obviously, this information can play a major role in the interpretation of the “doctrine of equivalents” by the patent attorney.
The selected example is the interpretation of the claim in U.S. No. 4,277,344 by FilmTec for a polymeric membrane formed by the reaction of a diamine and acid chloride such that there was a “plurality of uncrosslinked groups in the product.” A review of the prosecution history estoppel showed that the claim was allowed because it was unexpected and unusual for such a reaction to have unreacted groups. Thus, those who made a similar product with an essentially fully cross-linked product would not literally infringe nor would they infringe under the doctrine of equivalents.
The technical expert can play an important role in the interpretation of scientific terms. This again is a tricky area where at times the scientific and legal interpretations vary. Often the situation is simple where the scientific terms have been defined in the specification. But, at other times they have not. As an example, take the FilmTec patent ‘344 discussed above. What is the meaning of plurality? It is not defined in the specification; Webster’s dictionary defines it as more than 1. A chemist finds that description meaningless considering the billions of reactive groups in a gram of material. The definition of “plural” is crucial to the primary claim. The expert and patent attorney must work together to address this type of issue.
The scientific expert can also be valuable in the examination of primary documents such as laboratory notebooks. The scientist/engineer will see a method of experimentation and the thinking of the inventor. The expert can also see obviously missing but logical crucial experiments or data included, which seems oddly placed. Such a review of primary documents can be crucial in a patent infringement case in terms of the patent validity. Possibly there is important data that was not presented to the examiner that would have affected the claims allowed. Or, possibly, there is a problem with the inventorship. Again, discussions between the expert and the patent attorney can have an important role in shaping the strategy in a patent infringement suit.
Successful teams of scientists/engineers are those where each understands the unique expertise of the other and where this allows a working relation to develop the strongest approach in dealing with patent infringement issues.
Dr. Edward Funk has 20 years experience with Fortune 20 companies, including Corporate Research of Exxon and Corporate Technology for Honeywell. He specializes in the area of intellectual property. He is the author of six U.S. patents, and his R&D groups have generated over 60 patents. He has a B.S. in Applied Science from Yale and a Ph.D. in Chemical Engineering from the University of California, Berkeley. He has been a consultant since 1992, and holds a Visiting Professorship at the University of Illinois.