On 12 July 2017 the Supreme Court issued a decision on a patent infringement case that rocked the patent profession. For many years we have written the most important part of the patent specification, the claim on the basis that it would be interpreted fairly literally- using what was called “purposive construction”. This was despite the fact that EPC 2000 introduced an explicit provision in the protocol to article 69 that included the provision:
for the purposes of determining the extent of protection conferred by a European patent, due account shall be taken of any element which is equivalent to an element specified in the claims.
The decision came down clearly in favour of resurrecting the doctrine of equivalents in UK law. The approach recommended by the Supreme Court was that if infringement could not be found on the basis of a normal interpretation (literal), we should go back to a slightly updated version of what have been called the Improver questions. These are now to be understood as:
- Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, i.e. the inventive concept revealed by the patent?
- would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieved substantially the same result of the invention, that it does so in substantially the same way as the invention?
- Would such a reader of the patent of concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim (s) of the patent was an essential requirement of the invention?
On 1 November, an immense gathering of English patent attorneys and litigation lawyers (including some people like myself who wear both hats) took place to listen to a panel composed of two members of the Supreme Court that had made that decision (Lord Neuberger and Lord Sumption) as well as judges from Holland the USA and Germany. After the discussion, the chairman, Prof Sir Robin Jacob asked the patent attorneys in the room whether they felt that the new ruling clarified UK law. The vast majority thought that it did not. The litigators tended towards the opposite view.
Another important aspect of the case was whether it is possible to look into the patent office file to influence the interpretation of the claim. In this respect, the Supreme Court confirmed the existing law which allows us to look at the file only in very exceptional circumstances. These situations are now specified as:
- where the point at issue was truly unclear if one confined oneself to the specification and claims of the patent, and the contents of the file unambiguously resolve the point; or
- it would be contrary to the public interest for the contents of the file to be ignored.
In the present case, the patent attorney prosecuting the case had been subjected to persistent objections from the EPO examiner that his claim amendments That prudently strove to maintain reasonably broad protection for the inventive concept, introduced added subject matter. he was therefore compelled to limit the claim excessively to the specific embodiment quoted in the specification. Even though the limitation had been made deliberately, the Supreme Court did not think that the patent attorney should be held to the literal scope. In truth, this decision should be welcomed by patent attorneys as, to some extent, it rectifies any lack of foresight in the inventors and patent agent who prepared the application. This often takes little place long before the commercial significance of the inventive concept is truly appreciated.
However, inventors and, perhaps more importantly their commercial backers, still need to focus on how that single sentence at the end of the specification is crafted. Many inventors tend to want to claim the advantages of their invention rather than its technical features and suggest vague and indefinite wording, describing the function but not the engineering. Just as in the days when we made models of inventions (before my time) it really is important to give some clarity to your claim by identifying the essential elements with specificity. It is certainly a good idea to consider what variants achieve substantially the same result when drafting the specification but, if you miss one, don’t despair. The doctrine of equivalents may well yet save you.
If you are reading a patent specification today with the intention of ‘designing round’, this decision is definitely not your friend. Those who seek to design round are trying to achieve substantially the same result in the same way as the invention. They are looking for the errors and omissions that the doctrine of equivalents might well include within the scope of the claim.