Authored by E. Robert Yoches
The United States patent system has, as one of its key features, the incentive to design around others patents. This feature is one of the ways the patent laws promote the useful arts, as the United States Constitution instructs. By forcing others to avoid the claims of a patentee, the patent laws encourage creativity and innovation.
For most companies, however, the principal reason for designing around patents is to avoid infringement suits. To that end, companies must ensure that they do not waste their efforts on designs that infringe. Although there is always some risk of infringement—especially when technical or commercial realities require a design that may be close to certain claims—the goal is to minimize risk. What follows are some hints to help evaluate new designs and to decrease the chances that United States courts will find a design infringing.
II. HOW PATENTS AND PROSECUTION HISTORIES CAN POINT THE WAY TO EFFECTIVE NONINFRINGING DESIGNS
A. Claims
To assess infringement, everything starts with the claims. Patent claims contain a list of elements or limitations that define structural features or steps. The absence of any one of these limitations brings an apparatus or method outside the claims, and thus avoids infringement.
What seems like a simple task can often provide significant difficulty. Avoiding a limitation means knowing how to interpret that limitation properly. Although some claim terms have very little ambiguity, many have scopes that may require a full lawsuit to determine. To interpret claim terms properly requires a good knowledge of the rules of claim construction. Sometimes even such knowledge is not enough because the courts occasionally change the rules.
To complicate matters further, even when a limitation is not literally present, a device or method can still infringe under the Doctrine of Equivalents if the device or method has an equivalent for the missing element. The Doctrine is not available, however, if the patent contains a statement denying equivalence, or if the patent owner made an amendment or argument to the United States Patent and Trademark Office (USPTO) to obtain allowance of the claim, and that argument or amendment is inconsistent with the desired equivalence. The safest way to ensure a design does not infringe is to find limitations with defined boundaries and few or no equivalents. This requires looking to the specification of the patent or its prosecution history.
B. The Specification
Sometimes the specification of a patent specifically excludes certain features. This can happen, for example, when the specification is trying to distinguish a prior-art design, or when the specification tries to explain the superiority of the claimed invention to an alternative design. When the specification so clearly excludes certain features from a limitation, one can have confidence that a design with those features will not infringe the patent claim. A court must consider such “disclaimers” in understanding the meaning of a limitation. Disclaimers may also prevent application of the Doctrine of Equivalents if the disclaimers show no equivalence between the claimed and feature and the disclaimed subject matter.
Most patent draftsmen know to avoid disclaimers, so one seldom finds the clear and unambiguous statements necessary to avoid infringement with great confidence. Many times, disclaimers may be hidden. For example, if the specification requires that the invention meet certain conditions, such as a concentration in a chemical composition or a power level in a circuit, those conditions can effectively exclude embodiments that cannot meet those conditions.
C. The Prosecution History
It is far more common to find that the patent owner made limiting statements during prosecution in the USPTO. This is because the patent owner will often need to distinguish the claimed invention from prior art the USPTO examiner cited, which necessarily requires describing the claimed invention in limiting terms. The limiting statements may qualify as “prosecution history estoppel.” “Prosecution history estoppel” prevents a patent owner from using the Doctrine of Equivalents to reclaim subject matter the owner forfeited in arguments or amendments he made to obtain a patent. Again, there are a number of rules surrounding this concept, but if the patent owner says the claims do not include something, they probably do not literally or equivalently.D. Prior Art
Another way to avoid infringement is to “practice the prior art.” A patent claim that covers the prior art is invalid, so practicing the prior art will prevent interpreting a claim to be both valid and infringed. The problem with this approach, however, is that to be completely confident in avoiding infringement, the product or method must duplicate the prior art exactly. Otherwise, a patent owner may seize upon any differences between the prior art and the actual design to deny that a new design is in the prior art.
Because interpreting claims can be legally complex, it is important to involve a United States patent attorney in any design-around activities. Failure to do so could cause the company to spend substantial amounts of money on a design that may still infringe the claims of the patent of concern. At worst, the result would be a judgment of infringement, and damages as well as an injunction. At best, making a mistake on construing the claims would cause delays and the unnecessary expenditure of money in developing and testing a new design to replace one that may have received substantial investment. Either way, it is less expensive to involve an attorney early and regularly to ensure that the chosen design does not have infringement problems.
Ideally, a company should involve the attorney early enough in the design process to evaluate designs before they are complete. The company should also ask the attorney to evaluate any changes in design to ensure that the final design remains clear of the claims. If the attorney has been involved throughout the process, there may be no need for a formal written opinion on the final design. Such opinions are helpful, however, both to memorialize the fact that the company sought and followed legal advice, and to reduce the need to rely on memories, especially after key personnel leave the company.
Preferably, the company should seek an attorney who understands the technology at issue. This reduces the chances of an error through some sort of misunderstanding. In addition, if the company has a continuing relationship with the attorney, the attorney should notify the company of any changes in the law that may affect the opinion.
The confidence a company has that a new design is clear of a patent depends upon a proper analysis of the patent and its prosecution history. Although there are no guarantees a design will completely avoid patent claim, careful attention to rules of law can allow a company to maximize its confidence that it will not face serious problems later.
Copyright © Finnegan, Henderson, Farabow, Garrett & Dunner, LLP. This article is for informational purposes, is not intended to constitute legal advice, and may be considered advertising under applicable state laws. This article is only the opinion of the authors and is not attributable to Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, or the firm’s clients.
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