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Justin E. Gray

IP Litigation Attorney at Foley & Lardner LLP

Former Adjunct Professor at Northwestern University School of Law

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British Court of Appeal Provides Broad Overview of Claim Construction Principles

Ancon Ltd. v. ACS Stainless Steel Fixings Ltd., [2009] EWCA Civ 498 (Court of Appeal June 16, 2009) (Jacob, J.)

In this decision released today, the Court of Appeal contemplated the proper construction of the term "generally elliptical cone shape" for a bolt head that fit into a channel assembly. ACS argued that a proper construction of this term would at least call for "the presence in the head of at least one portion which is more or less oval." In support of its argument, ACS cited to the drawings of the patent (all of which presumably showed a generally oval portion of the head), language in the specification, and the proposition that if the patentee had intended to receive broader coverage for his claim, he could have used different language than that present in the claim.

In an opinion by Lord Justice Jacob, the Court of Appeal took this opportunity to summarize its relevant claim construction principles, which, unlike claim construction in the United States, focus on a "purposive construction." The Court recognized that patentees are often faced with the familiar problem "to describe something which, at any rate ... is new; which has not existed before and of which there may be no generally accepted definition." Ancon, ¶ 25.

In the British system, "claims are to be construed in context" and while "the extent of protection is determined by the terms of the claims ... the description and drawings shall [also] be used to interpret the claims." Id. ¶ 5(b). Claims are construed purposively, "the inventor's purpose being ascertained from the description of the claims." Id. ¶ 5(c). "Purpose is vital to the construction of the claims." Id. ¶ 5(d).

To be sure, "purpose" and "meaning" are different: "there is no presumption that the patentee necessarily intended the widest possible meaning consistent with his purpose be given to the words that he used." Id. ¶ 5(e). However, "meaning" is still important. "[I]f the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements." Id. ¶ 5(g). When a patentee uses a word "which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context ... [the ultimate question is] what does the word or phrase actually mean, when construed purposively? That can only be done on the language used, read in context." Id. ¶ 5(h).

The Court went on to discuss the relationship between "purposive construction" and the lack of doctrine of equivalents in the British system. "[P]urposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context." Id. ¶ 5(j).

Finally, the Court noted that purposive construction eschews what has been called "the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge." Id. ¶ 5(k). Over-meticulousness is not the same as carefulness: "[c]are in working out what the patentee was aiming at when he chose the words he used is absolutely necessary." Id. The compulsory question is "what would a person skilled in the art have understood the patentee to have used the language of the claim to mean?" Id. ¶ 10.

In this case itself, the Court reasoned that the purpose of the shape of the bolt head is to achieve a camming action into the corners of the channel. Therefore, the shape of the sides of the bolt are important, not the shape of the top. While the accused bolt head had a slight bevel at its base, the Court found that this fact would not matter for purposes of infringement as there was "no technical difference" between the accused bolt head and that described by the claim.

This decision provides practitioners a thorough introduction to the details of United Kingdom patent claim construction.

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