The German Federal Supreme Court has established a three-step-test to determine infringement under the doctrine of equivalence. According to this test, the third step (“equivalence”) requires that the considerations of the skilled person for finding the surrogate, equivalent means are based on the patent claim and the patent specification in such a manner that the skilled person considers the differing embodiment with its modified means as a technical solution which is equivalent to the technical teaching of the patent. However, there is no such equivalency if the wording of the claim shows that the patent applicant decided to select a specific means for achieving a certain effect while abandoning other surrogate means – namely the attacked means – which are disclosed in the patent specification as being capable of achieving the same effect (cf. Federal Supreme Court, GRUR 2011, 701 – Okklusionsvorrichtung; Federal Supreme Court, GRUR 2012, 45 – Diglycidverbindung). The Dusseldorf Appeal Court now clarifies that such a decision to select specific means from a set of alternatives and to abandon the alternatives may only be assumed if the patent specification shows that the patent applicant was aware of the alternative means achieving the same effect and consciously decided not to claim these alternative means.

In the case at hand, the plaintiff was the owner of the German part of European Patent 1 199 020 B1 (“patent-in-suit”) concerning a hinge for a toilet seat for securing a toilet seat assembly to a ceramic body. The hinge in accordance with claim 1 of the patent-in-suit included an adapter member with an approximately cylindrical base body in which a radial blind bore was formed for insertion on a gudgeon (feature 4.3 of claim 1). The defendant produced and distributed various toilet seat assemblies with hinges. One of these assemblies (“attacked embodiment I”) included an adapter member with a radial blind bore, whereas two of the defendant’s assemblies (“attacked embodiment II” and “III”) included adapter members with a stepped bore, going all through the adapter members.

The plaintiff filed an infringement suit with the Dusseldorf District Court asserting literal infringement of claim 1 of the patent-in-suit by the defendant’s attacked embodiment I and equivalent infringement by the attacked embodiments II and III. The Dusseldorf District Court decided in favor of the plaintiff as far as literal infringement by the attacked embodiment I was concerned, but dismissed the complaint with regard to the alleged equivalent infringement by the attacked embodiments II and III. Notably, it was undisputed among both parties that the adapter members of the attacked embodiments II and III did not include a radial blind bore, and, therefore, literal infringement of claim 1 was out of the question. Equivalent infringement in view of the attacked embodiments II and III was also denied by the Dusseldorf District Court:

According to the aforesaid three-step-test, there is a patent infringement under the doctrine of equivalence, if the attacked embodiment does not make literal use of a certain feature of the patent claim, but provides a surrogate means which is equivalent to this feature of the patent claim. The surrogate means in question must meet the following conditions: (1) The surrogate means of the attacked embodiment must have an “equal effect” as compared with the feature of the patent claim which is not literally realized. This means, the problem of the invention must be solved with means having objectively identical effects. (2) The surrogate means must be “obvious” to a skilled person at the priority date. This means that the skilled person must be able to discover the surrogate means as having identical effects without any inventive considerations and on the basis of his expert knowledge. (3) The skilled person must consider the surrogate means as being “equivalent” to the teaching claimed in the patent. This means that the considerations of the skilled person for finding the surrogate, equivalent means must be based on the patent claim and the patent specification in such a manner that the skilled person considers the differing embodiment with its modified means as a technical solution which is equivalent to the technical teaching of the patent. However, there is no such equivalency if the wording of the claim shows that the patent applicant decided to select a specific means for achieving a certain effect while abandoning other surrogate means – namely the attacked means – which are disclosed in the patent specification as being capable of achieving the same effect.

The Dusseldorf District Court held that the third requirement was not fulfilled since claim 1 of the patent-in-suit explicitly referred to a “blind bore” (i.e. a bore which does not go all through the drilled material), while the specification of the patent-in-suit mentioned various kinds of bores, for example “bores” in general, and, more specifically, “blind bores”, “(drilled-)through bores” and “stepped bores”. Therefore, the Court regarded the use of the term “blind bore” in feature 4.3 of claim 1 as a selective decision (“Auswahlentscheidung”), excluding the attacked embodiments II and III with its “stepped (through-)bores” from equivalent infringement. In the present decision, the Dusseldorf Appeal Court affirmed the Dusseldorf District Court’s judgment as far as literal infringement of claim 1 by the attacked embodiment I was concerned, but set aside the District Court’s judgment as far as it dismissed the action in view of the alleged equivalent infringement of claim 1 by the attacked embodiments II and III.

With respect to the third requirement under the doctrine of equivalence (“equivalence”), the Dusseldorf Appeal Court outlined that special circumstances need to be at hand for excluding “obvious” surrogate means having the “same effect” from patent protection under the doctrine of equivalence. Generally, such special circumstances may only be assumed if the patent specification shows that the patent applicant was aware of the alternative means achieving the same effect and consciously decided not to claim these alternative means (“selective decision”; “Verzichtssachverhalt”). The Dusseldorf Appeal Court stated that, in the case at hand, the skilled person can detect from the functional term “formed for insertion on a gudgeon” contained in claim 1 that according to the patent claim the function of the bore is decisive. When reading the patent specification the skilled person cannot find a hint that – for realizing said function – the technical teaching of the patent-in-suit depends on a bore with a closed bottom, meaning a “blind bore”. Instead, according to the patent specification, the technical teaching depends on the fact that the radial bore is formed for insertion of a gudgeon and that the radial bore provides a stop for preventing the gudgeon from slipping through. In the case at hand, various kinds of bores were mentioned in the specification – however, they were not mentioned in the context of the relevant feature 4.3 of claim 1, i.e. as means to mount the hinge to the ceramic body. Against this background, the Court did not see hints in the patent-in-suit suggesting that the patent applicant was aware of “stepped (through-)bores” having the same, equivalent technical effect. Thus, the Court denied a selective decision of the patent applicant excluding “stepped (through-)bores” from (equivalent) patent protection. The Court further explained that a selective decision of the patentee against certain alternative means – by not mentioning them in the wording of the claim – could also not be inferred from the fact that these alternative means were so obvious to the skilled person that the patent applicant must have known of them.

Therefore, the Dusseldorf Appeal Court found equivalent infringement, in the case at hand.

The present decision of the Dusseldorf Appeal Court is remarkable and fortunately clarifies the recent case law of the German Federal Supreme Court on the doctrine of equivalence (cf. Federal Supreme Court GRUR 2011, 701 – Okklusionsvorrichtung; Federal Supreme Court GRUR 2012, 45 – Diglycidverbindung). In view of the Federal Supreme Court’s decisions “Okklusionsvorrichtung” and “Diglycidverbindung” and respective case law of Dusseldorf Appeal Court, it has been claimed by many practitioners in the field of patent law that patent infringement under the doctrine of equivalence was “dead”. In fact, in the last few years, no case of established equivalent infringement has been reported in Germany. With respect to the existing case law, it has been claimed by practitioners that there was no equivalent patent infringement if the surrogate means is mentioned in the patent specification. Allegedly, only if the surrogate means is not mentioned in the specification, there was no “selective decision” with respect to the means specified in the wording of the claim. This approach made things complicated as the surrogate means might not be “obvious” for the skilled person if it is not mentioned in the specification at all. Thus, the Dusseldorf Appeal Court’s statements that a “selective decision” can only be assumed under special circumstances are highly appreciated. Thus, the present decision might encourage plaintiffs to argue equivalent infringement more often again.

The present decision should be carefully considered when applying for a patent and drafting the claim and the specification: Surrogate means should either be included in the scope of literal patent protection by skillfully phrasing the wording of the claim(s), or – if this is not possible – they should not be mentioned in the patent specification at all. In the latter case, it should be considered whether the function of the claimed means can be mentioned in the wording of the claim and whether such function can be further illustrated in the patent specification. The chance of gaining patent protection under the doctrine of equivalence by means of a precise description of the function should outweigh the risk of including determinations allegedly limiting the scope of protection. In the absence of accepted generic terms for describing the means and the function, the patent applicant may create its own terminology, in this regard. In this context, it should be noted that, under German Patent law, the patent is regarded to be its own “dictionary” and is to be understood out of itself (Federal Supreme Court GRUR 1999, 692 – Spannschraube).