Life on Pemetrexed: Hit by the DoE pendulum swinging back

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Case No. S2018_006 | Decision of 8 February 2019

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The plaintiff in this infringement case is CSEM, the patentee of EP 1 422 436 B1; see Swissreg and the EPO register for further bibliographic information about the patent in suit.

CSEM sued Cendres+Métaux Microtech AG and Cendres+Métaux SA for infringement of EP’436. The attacked embodiment is the CMK1 movement that features a hairspring made of silicon:

CMMT‘s CMK1 movement

Interestingly, the decision also notes that EP’436 had already been challenged in a nullity case at the FPC, i.e. O2012_015. That case had been settled after the second ordinary judge Tobias Bremi had provided expert opinions in his capacity as judge-rapporteur; these opinions had held that the patent was valid.

Ulysse Nardin logo

O2012_015 apparently is the case L’ AGEFI had reported about already back in 2013: This was an earlier dispute with Sigatec (a joint-venture of Mimotec and Ulysse Nardin). A hearing in O2012_015 had been announced on the FPC’s website twice (for 21 October 2013 and 29 November 2013), but the announcement disappeared in both instances well before the hearing. That fits nicely with L’AGEFI’s report on Friday, 29 November 2013 that the settlement had been reached a few days in advance of the hearing scheduled for exactly that Friday (‘ce vendredi’). Note that Ulysse Nardin had apparently been the first brand to introduce a silicon component in a wristwatch, with a silicon escapement in ‘The Freak’ of 2001:

Ulysse Nardin’s ‘The Freak’ (2001)

Infringement of the patent

CSEM asserted the patent only to the extent of independent claim 1 (features 1.1 to 1.7) in combination with dependent claim 2 (feature 2); i.e., the following features are at stake, in English (translation) and French (language of the proceedings of the patent):

  English translation French (orig.)
1.1 A hairspring intended to equip the balance wheel of a mechanical timepiece and Ressort spiral destiné à équiper le balancier d’une pièce d’horlogerie mécanique et
1.2 in the form of a spiraled rod (10) cut from an {001} single-crystal silicon plate formé d’un barreau (10) en spirale issu du découpage d’une plaque {001} de silicium monocristallin
1.3 having a first thermal coefficient (C1) and a second thermal coefficient (C2) of its spring constant C présentant des premier (C1) et deuxième (C2) coefficients thermiques de sa constante de rappel C,
1.4 the turns of said hairspring having a width w and a thickness t les spires dudit ressort spiral ayant une largeur w et une épaisseur t,
1.5 said rod comprises a silicon core (12) and ledit barreau comportant une âme (12) en silicium et
1.6 an external layer (14) of thickness ξ formed around the silicon core une couche externe (14) d’épaisseur ξ formée autour de l’âme en silicium et
1.7 made of a material having a first thermal coefficient of the Young’s modulus of opposite sign to that of the silicon constituée d’un matériau présentant un premier coefficient thermique du module d’Young de signe opposé à celui du silicium
2 said external layer (14) is made of amorphous silicon oxide (SiO2). ladite couche externe (14) est réalisée en oxyde de silicium (SiO2) amorphe
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The defendants argued that the highlighted features in 1.2 were not fulfilled in the attacked embodiment, i.e. that i) the spiraled rod is not ‘cut from’ a silicon plate, but rather worked out by way of a plasma-assisted etching method ; and ii) the orientation of the silicon plate is not {001}, but rather {110}.

With respect to the feature ‘cut from’, the decision holds in ¶22 that a proper construction in view of the specification shows that this feature is not limited to a cutting process in a narrow literal sense, but rather has to be understood in the sense of ‘working out’. Both parties had apparently not put forward any construction of the feature. Still, claim construction is a question of law. The decision holds that the defendant’s assumption is mistaken that the court must not construe the ‘cut out’ feature in the sense of ‘working out’ in the absence of an allegation to that effect by the plaintiff:

Da die Auslegung des Patentanspruchs eine Rechtsfrage ist, geht die Annahme der Beklagten fehl, das Gericht dürfe den Anspruch mangels entsprechenden Vortrags der Klägerin nicht so auslegen, dass er auch etwas anderes als einen Schneidprozess erfasst.

With respect to the orientation of the silicon plate, things are getting interesting. It was beyond dispute that there is an outer layer of SiO2 around the silicon core in the attacked embodiment. See the microscopic images of a broken hairspring in ¶11 of the decision:

Broken hairspring; enlarged microscopic images (left: 4’000x; right: 15’000x)

The decision notes that it is not possible to spot features 1.5-1.7 without destroying / breaking the hairspring. This was apparently undisputed and/or known to the court (‘[u]nbestritten respektive gerichtsnotorisch’).

CSEM did not dispute that the orientation of the silicon plate was not {001}, but rather {110}. Thus, only infringement under the doctrine of equivalents (DoE) was at stake, from the very beginning. An interesting factual setup for applying the DoE, in particular in a world after ‘Pemetrexed’.

Firstly, the decision recalls the checklist that the FPC applies in the assessment of infringement under the DoE in Switzerland, with reference to O2015_018 (¶60). Indeed, the same wording of the three questions has already been used in O2015_015 (in French language), i.e.:

Q1: Same effect (‘Gleichwirkung’)

In conjunction with the other technical features of the patent claim, does the modified feature objectively fulfil the same function as the claimed feature?

Erfüllt das abgewandelte Merkmal im Zusammenwirken mit den übrigen technischen Merkmalen des Patentanspruchs objektiv die gleiche Funktion wie das beanspruchte Merkmal?

Q2: Accessibility (‘Auffindbarkeit’)

Is the same function obvious for the skilled person from an objective point of view, taking into account the teaching of the patent, when the features are exchanged?

Ist die Gleichwirkung für den Fachmann bei objektiver Betrachtung unter Berücksichtigung der Lehre des Patents offensichtlich, wenn die Merkmale ausgetauscht sind?

Q3: Equal value (‘Gleichwertigkeit’)

Does the skilled person who has read the patent objectively come to the conclusion that the patentee has formulated the claim — for whatever reason — so narrowly that he does not claim protection for an embodiment that has the same effect (Q1, above) and is accessible (Q2, above)?

Gelangt der Fachmann bei objektiver Lektüre der Patentschrift zum Schluss, der Patentinhaber habe den Anspruch — aus welchen Gründen auch immer — so eng formuliert, dass er den Schutz für eine gleichwirkende und auffindbare Ausführung nicht beansprucht?

Further, the genesis and the prosecution history of the patent is not decisive for claim construction and, thus, for the scope of the claims:

Die Entstehungsgeschichte bzw. das Erteilungsverfahren ist für die Auslegung der Patentansprüche und damit auch für die Bestimmung des Schutzbereichs grundsätzlich nicht massgebend.

Interestingly, the defendants did not really challenge that both the first and the second question were to be answered in the affirmative. Thus, it all boils down to the ‘right’ assessment of only the third question, and/or whether the applicant has waived any rights to claim infringement under the DoE.

In a first step, the decision analyses what the skilled person concludes from the patent specification itself in respect of the relevance of the orientation of the silicon plate. The orientation is mentioned quite often. But it is held that the skilled person does not get any indication from the patent specification per se that the patentee has formulated the claim so narrowly that he does not claim protection for an embodiment of same function (Q1) that is accessible (Q2). In particular, from an obvious point of view, it cannot be inferred from the claim — even when taking the description into account — that conformity with the primary wording is one of the essential requirements of the invention.

The aftermath of ‘Pemetrexed’

Boom! Welcome to the post-‘Pemetrexed’ world. Would you have guessed that before the Supreme Court decisions in Germany, the U.K. and Switzerland?

After having dealt with the patent as such, the decision also assesses whether the applicant might somehow have waived his right during prosecution to now allege infringement under the DoE. Therefore, one may well consider the prosecution history.

The decision emphasizes that from an amendment of the claims, wherein the attacked embodiment was literally covered by the originally filed claims but is no longer literally covered by the amended claims, it cannot automatically be concluded that the applicant intended to waive protection for this embodiment. Rather, the reason for the amendment is decisive. Only if the amendment was made to overcome objections relating to the attacked embodiment — e.g. in view of free prior art for the attacked embodiment — one may conclude that the applicant has waived protection for equivalents of the amended feature. The Swiss Supreme Court in 4A_208/2017 (¶5.5.8) had referred to and agreed with the corresponding 'Pemetrexed' judgment of the German Supreme Court which had held in ¶68 that

[…] if the amendment was made with regard to formal requirements […] or if it is not sufficiently clear for what reason it was made, a selection decision […] cannot normally be assumed.

Further, the decision holds that a waiver of protection for equivalents could be assumed if the specification of the patent shows (at least) two concrete embodiments with which the inventive effect can be achieved, but only one of these embodiments is reflected in the claim (see 4A_208/2017 (¶5.5.4), with reference to X-ZR 29/15 of the German Supreme Court (hn).

Now, how did that play out in the present case?

The prosecution history does not make clear why the orientation of the silicon plate that had originally been specified in dependent claim 2 had later been included in claim 1. The independent claim had been re-drafted after receipt of the search report on the application as filed. The search report mentioned two documents of category ‘X’ (highly relevant), including JP 06-117470 A. But the subsequent limitation of claim 1 also included yet further features of claims 3 and 4, and the applicant’s submission to the EPO of 12 November 2004 lacks any explanation as to the motivation of the amendment. Because the two ‘X’ documents were considered relevant for the patentability of claims 1 and 2 only (which indicates that the features of claim 2 did not appear to be a sufficient limitation) and because only the features of claim 4 were included in the characterizing part of the amended claim, the skilled person cannot easily assume that the limitation to the orientation {001} was made in order to delimit the subject matter of the patent from the prior art. For this purpose, the inclusion of the features of claims 3 and 4 while omitting the features of claim 2, would have been sufficient. With the further limitation, the applicant possibly wanted to pro-actively an anticipated objection of undue extension of subject-matter (Art. 123(2) EPC) or insufficiency of disclosure (Art. 83 EPC). It is therefore not sufficiently clear why the specific limitation had been made.

Further, the decision emphasizes that the limitation did not distinguish the claimed subject-matter from the free prior art for the attacked embodiment. JP 06-117470 A does not reveal an outer layer that encloses the silicon core as it is in the attacked design. It therefore does not represent a free prior art for the attacked embodiment. Even if one were to assume that the limitation would have been made to distinguish the invention from JP 06-117470 A — which is not sufficiently clear — it cannot in any case be said that the limitation was made with regard to the free prior art for the attacked embodiment. The skilled person therefore cannot and must not assume that patent protection is not sought for embodiments of same effect (Q1) which are accessible for him as a skilled person, with knowledge of the invention (Q2).

What remains to be dealt with in accordance with ‘Okklusionsvorrichtung‘ and ‘Diglycidylverbindung‘ (and as confirmed in 'Pemetrexed') is the question of whether or not there was a situation of, in simple terms:

What is (specifically disclosed but) not claimed is disclaimed.

The decision holds that the patent does not reveal at least two specific embodiments of which only one is claimed. The unique specific embodiment that is disclosed uses silicon wafers of orientation {001}. The defendants have pointed out that the plaintiff admitted (apparently in the written proceedings before the FPC) that the patent when read together with JP 06-117470 A taught the expert that the three crystal orientations of the silicon plate were of same effect for the purposes of the invention. However, this was of no avail. It only establishes that Q2 has to be answered in the affirmative, i.e. that the same effect of the replacing feature had been accessible for the skilled person. It does not mean that specific embodiments were disclosed in the specification of the patent itself. The mere fact that the applicant could have recognized that silicon plates of orientation {110} have the same effect as those of orientation {001} in the context of the invention is not sufficient. Otherwise protection under the DoE for replacing features of same effect (Q1), which could be readily found by the skilled person (Q2), would be excluded because of the third question — what cannot be it:

Dass die Anmelderin hätte erkennen können, dass Siliziumplatten der Orientierung {110} für die Erfindung gleich wirken wie solche der Orientierung {001}, genügt nicht. Denn sonst wäre ein äquivalenter Schutz für gleichwirkende Lösungen, die für den Fachmann auffindbar waren, wegen der dritten Frage ausgeschlossen, was dazu führen würde, dass es keine auffindbaren gleichwirkenden Lösungen gäbe, die als äquivalent zur beanspruchten Lösung zu betrachten wären.

Anyway, it appears that the mentioning of JP 06-117470 A had only been introduced in the specification during prosecution, after receipt of the search report; the respective paragraph [0008] of the patent as granted is missing in the application as filed.

In sum, the patent to the extent asserted was held to be infringed under the DoE.

Validity of the patent

Novelty was not an issue. But the defendants argued for obviousness as a plea in defense. They proposed EP 732 635 A1 as closest prior art in the assessment of obviousness. The plaintiff disagreed with that choice and argued that EP'635 was totally unsuitable (‘denkbar ungeeignet’) — but did not propose a better one. In any event, the decision holds that EP'635 is not totally unsuitable in that it does not lead to an undue ex post facto analysis. Thus, for that it had been relied upon by the defendants, it has to be assessed; ¶24.

The decision holds that EP'635 did not disclose features 1.2, 1.7 and 2. Next, the decision defines the objective technical problem as follows:

[T]o further develop the hairspring of a balance with a view to increasing the accuracy of a mechanical movement equipped with it, even under external influences on the same.

The decision holds that EP'635 is not of much help in solving the objective technical problem. First, because EP'635 already claims to provide items that are insensitive to temperature influences; see EP'635 in col. 4, l. 45-48. Second, EP'635 is primarily about anchors, not hairsprings.

The defendants relied on US 5,783,973 and US 2002/0104475 A1 to bring in the distinguishing features, but both attempts failed.

In sum, the subject-matter of claim 1 was held to be non-obvious; the same applies to the subject-matter of the combination of claim 1 with dependent claim 2.

Interim injunctive relief

Having established that a valid claim is infringed, the decision turns to the requirements for interim injunctive relief.

The decision holds that it was not made plausible that Cendres+Métaux SA, the parent company of Cendres+Métaux Microtech AG, actually contributed to the infringement. The plaintiff’s request for interim injunctive relief against Cendres+Métaux SA was thus dismissed.

The defendant’s also argued that there was no threat of a not easily reparable harm for CSEM since it is only the licensor of the patent to the ‘consortium’, and that license was exclusive. In turn, CSEM argued that the license fee was based on a royalty per unit (‘Stücklizenzgebühr’) and that it acted as a second source of supply for hairsprings according to the patent in suit, which was held sufficient to establish a not easily reparable harm.

Horage logo

Finally, was the matter (still) relatively urgent? CSEM argued to have gained positive knowledge of the infringement only in August 2018, while the defendants argued that CSEM should / could have known since as early as 2013. Indeed, e.g. Andreas Felsl mentioned in an interview in 2013 that the new movement

did not encroach on existing patents. We did all we could to avoid being taken to court.

Screenshot from (visited 23 February 2019)

The decision holds that CSEM had no reason to make further inquiries due to the above statement. The infringement is not obvious from public documents,  and there is no obligation to acquire and destroy potentially infringing embodiments in the market in order to be able to prove an infringement. Therefore, CSEM cannot be blamed for having abusively waited with the request until September 2018 and thereby forfeited its right to interim injunctive relief.

Food for thought

  1. How much patent / legal knowledge does the skilled person have?

What I find interesting is that the decision walks the reader through each and every occasion where the patent specification deals with the orientation of the silicon plate in ¶36, and holds that the skilled person attributes the explanations in [0023], [0025], [0028], [0030] and [0031] of EP’436 to the specific embodiment only, and will not consider them to be directly relevant for the assessment of the scope of protection.

Further, the skilled person also draws conclusions from the fact that a feature is placed in the so-called characterizing part of an independent claim; see ¶39.

Really? Why is that?

The skilled person had been defined as a a micromechanic specialised in the field of mechanical watchmaking, working in a team with a physicist specialising in microfabrication techniques; ¶20. How comes that these tech people have the patent / legal skills to distinguish between a general, binding teaching in a patent on the one hand, and the merely explanatory examples on the other hand? The aforementioned paragraphs are not introduced with a wording like ‘non-limiting examples’ or sth similar to that effect. The distinction between limiting and non-limiting teachings in a patent requires quite some patent / legal experience, but no such qualification is apparent from the definition of the skilled person.

Similarly, I doubt that the skilled person(s) as they had been defined are aware of the dos and don’ts of claim drafting, e.g. the distinction between the preamble and the characterizing part of a claim and how to place the features therein.

  1. Which effect(s) is/are to be taken into account in the assessment of Q1?

Specifically with respect to the first question, the present decision refers to the Supreme Court decision 143 III 666 — Pemetrexed (¶5.3.3) and the FPC’s decisions S2013_001 — Drospirenon (hn) as well as O2014_002 — Urinalventil (¶ But the exact wording of the first question is not taken from any of the referenced decisions. In particular, the Supreme Court held in 143 III 666 that the allegedly infringing embodiment must achieve all those effects which, according to the skilled person’s understanding, are to be achieved by the attacked embodiment with the individual technical features of the claim per se and in their interaction (emphasis added):

Die abgewandelte Ausführungsform muss alle diejenigen Wirkungen erzielen, die nach dem Verständnis des Fachmanns mit den einzelnen technischen Merkmalen des Patentanspruchs für sich und in ihrem Zusammenwirken erzielt werden sollen.

This does not necessarily imply that the modified feature of the allegedly infringing embodiment has only one single function or effect. A feature may well, and in my perception typically does, have more than just one single function or effect. S2013_001 does not provide any further clarification in that respect, either; the wording of Q1 in the hn is even shorter, and also uses the singular: Does the replacing feature objectively fulfil the same function? Finally, O2014_002 only refers to the ‘relevant’ function of the feature in ¶, thus implicitly accepting that there may well be other (potentially less relevant?) functions — and subsequently indeed only discusses one single function.

Moreover, Q1 only refers to the function or effect of the replacing feature. In my reading, this adresses the function or effect of that feature per se only, but does not readily address the interaction of that feature with the other features in the attacked embodiment, and the function(s) or effect(s) of the attacked embodiment as a whole.

I am very much looking forward to a decision that actually expands a bit more on the effect(s) that is/are to be considered in Q1 under the DoE.

Reported by Philippe KNÜSEL and Martin WILMING


Case No. S2018_006 | Decision of 8 February 2019

CSEM Centre Suisse d’Electronique et de Microtechnique SA


  1. Cendres+Métaux Microtech AG
  2. Cendres+Métaux SA

Panel of Judges:

  • Dr. Mark SCHWEIZER
  • Dr. Philipp RÜFENACHT
  • Dr. Lorenzo PARRINI


  • Dr. Philipp RÜFENACHT

Court Clerk:


Representative(s) of Plaintiff:

  • Dr. Andri HESS (Homburger)

Representative(s) of Defendant:

  • Dr. Demian STAUBER (Rentsch Partner)
  • Fabio VERSOLATTO (Rentsch Partner)


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EP 1 422 436 B1

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