In its decision Medinol vs Abbot, the Dutch supreme court has clarified the law on use of claim construction to import limitations that are not present in the literal meaning of a patent claim.
The court held that a variant of the subject matter within the literal scope of protection should be excluded from protection if, from the perspective of the skilled person at the priority (filing)date, the problem solved by inventive contribution did not exist for that variant. This was justified by the “fair protection” consideration from the protocol on claim construction of the European patent convention (EPC). Under the protocol, this consideration could be used not only to broaden but also to narrow protection. The court observed that the case law of the boards of appeal of the European patent office (EPO) on claim construction was not relevant for the national courts because it did not concern the infringement context.
The problem for an improved stent
The case in question concerned a tube shaped stent with successive mesh patterns on the surface of the tube, each having a periodic layout around the circumference on the tube. The invention added a specified type of connection between successive patterns. In the patent’s description, connections between patterns had periods that were 180 degrees out of phase, but the claim arguably did not exclude in-phase patterns. Nevertheless the court excluded this from protection.
The court held that claim construction had to be performed from the perspective of a skilled person at the priority (filing) date. The patent stated the problem to minimize shrinking of the stent. According to the court, at the priority date the skilled person would find that this problem did not arise for in-phase stents and hence application to such stents was outside the essence of the invention. Based on this, claim construction excluded in-phase stents from protection. It was irrelevant whether the problem did actually exist for in-phase stents if the skilled person could know this only after the priority date.
Essence of the invention
The Dutch supreme court has a long tradition of using the “essence of the invention” or “inventive contribution” as instrument for establishing the scope of patent protection. For a long time, case law obliged courts to determine the essence of the invention as a starting point for establishing the scope of protection, for both claim construction and equivalents protection without distinction. This case law has since gradually been whittled down, eventually reducing the “essence of the invention” to merely “a viewpoint” for claim construction, which some saw as its demise.
The Medinol decision shows that this viewpoint can still be solely dispositive for claim construction. Because the essence of the invention included solution of a problem of out-of-phase stents, not in-phase stents, the supreme court confirmed that claim construction excluded the latter from patent protection. This was held to be consistent with the EPC protocol on claim construction, because that protocol explicitly extends the role of claim construction beyond merely clarifying claim terms. The supreme court distinguished claim construction from equivalents protection, which involved the perspective of the skilled person at the priority date and the date of infringement respectively. Hence post-priority discoveries about existence of the problem for in-phase stents were irrelevant for claim construction.
Although the court depicts it as merely “a viewpoint”, the “essence of the invention” seems inevitably dispositive when it is used to limit the scope of protection, at least if the patent does not describe the excluded variant. When the “essence of the invention” is used to extend protection, other viewpoints like those involving legal certainty for third parties might prevail, e.g. in the case of subject matter that was clearly left unclaimed or distinction from the prior art. But the court did not suggest viewpoints that could overrule the “essence of the invention” when it is used to narrow protection.
The decision is in line with the worldwide policy trend against patent protection of subject matter that is not explicitly supported by a patent. Perhaps, patentees may derive some consolation from the fact that the “essence of the invention” enables enforcement of this policy by claim construction rather than by complete invalidation, at least if it may be assumed that claim construction using the essence of the invention also applies for decisions on validity.