Last week in Siemens v Thorn1 Mr Justice Mann held that Siemens' patent was valid and infringed. Although this is newsworthy in itself, some other interesting issues arose in this case. The first relates to what the "authentic" language of a patent is for the purposes of construction. The second relates to the application of the newly amended section 68 Patents Act 1977 ("PA 77") and the bar on recovery of damages and costs in the event of non-registration of patent assignments.


This was a patent infringement action brought by Siemens against Thorn in the UK Patents Court. The patent in suit related to "a printed circuit board [PCB], having a protective coating made from an electrically insulating, thermoplastic material, and a process for manufacturing such a printed circuit board with protective coating." That is, a method of protecting PCBs once they had been made by covering the PCB with a film and then fusingthe PCB and the film. The film (or thermoplastic material) included wax to improve its flow properties. This wax was also claimed to "facilitate through-plating and soldering operations through the protective coating…" Thorn counterclaimed for revocation of the patent.

The judge found in favour of Siemens on infringement and validity. However, we report here on two specific aspects of Mann J's judgment.

Authentic language of the patent and construction

The patent in suit was a European Patent, originally filed at the European Patent Office in the German language. German was the "language of the proceedings" (for the purposes of s.80 PA 77) but an English translation was filed in accordance with s.77 PA 77.

Construction of the English terms fused (the German language patent used the words "aufgeschmolzen") and through-plating (where the German text uses the term "durchkontaktierung") was in issue. The two terms potentially meant different things depending on whether one was considering the English translation or the original German text. So which document should the court consider when construing the patent?

s.80 PA 77 sets out the status of the two documents. It states that the language of the text of the European patent or application shall be the language for the purposes of proceedings before the EPO and this language shall be the "authentic" language for the purposes of any domestic proceedings. However, s. 80 continues by stating that where the language of the proceedings is French or German, a translation into English of the specification and claims, shall be treated as the authentic text for the purposes of domestic proceedings, other than proceedings for the revocation of the patent, if the patent as translated into English confers protection which is narrower than that conferred by it in French or German. 

So, in this case for the purposes of the revocation proceedings, the German text should be construed and the English translation used for determination of infringement provided this text confers narrower protection on the patentee than that conferred by the German text. The judge stated that it was not permissible in this situation to cross-fertilise between translations and use one text to assist with the construction of the other text.

Non-registration of assignment and recovery of damages

Siemens' title in the patent in suit arose from a number of transfers in ownership effected as a result of Swiss merger proceedings. The earlier mergers were not registered within the requisite 6 month period although the last merger was. Thorn argued that all merger events should have been registered under s.33 PA 77 and, as they were not, there was a bar to Siemens' recovery of damages. Siemens' countered by stating that the bar to recovery of damages no longer applied post-amendment to s.68 PA 77 which Siemens contended acted retrospectively and that in any event the merger events were not registrable under s.33.

By way of background, s.68 PA 77 was amended last year to implement the Enforcement Directive 2004/48/EC. The amendment (which came into force on 29 April 2006) removed the bar on recovery of damages for non-registration of assignments (and other registrable transactions) and replaced it with a bar on recovery of costs or expenses, as follows:

"s.68. Where by virtue of a transaction, instrument or event to which section 33 above applies a person becomes the proprietor or one of the proprietors or an exclusive licensee of a patent and the patent is subsequently infringed, before the transaction, instrument or event is registered, in proceedings for such an infringement, the court or comptroller shall not award him costs or expenses unless -

a. the transaction, instrument or event is registered within the period of six months beginning with its date; or

b. the court or the comptroller is satisfied that it was not practicable to register the transaction, instrument or event before the end of that period and that it was registered as soon as practicable thereafter."

Did the new s.68 PA 77 have retrospective effect as argued by Siemens? The judge pointed out that there was nothing in the amendment to expressly state that it operated retrospectively. There was a presumption against the retrospective effect of legislation and there was nothing in the statute or the amending regulation to rebut that presumption.

Mann J then considered whether the Swiss merger events were registrable transactions under s.33 PA 77. The merger events in question transferred the patent in suit by operation of law under the Swiss doctrine of Universal Succession. As such, Mann J found that (regardless of how unattractive the finding may be) such events were not registrable events under s.33 PA 77. Mann J accepted that it was difficult to see why the merger events ought to fall outside s.33 PA 77 but the wording in this section was clear. As a result there does appear to be a lacuna in relation to these types of transfers of patent rights.


This case was interesting for raising the above issues on ss.80 & 68 PA 77. Practical points resulting from the decision include:

  • On the translation point, if patents have been filed at the EPO in a different language, both the translation and the original document should be construed as if they were both originals in order to ascertain whether the scope of protection is the same in each case (this is relevant for both the patentee and the alleged infringer);
  • On the s.68 PA 77 point, although Siemens escaped the old s.68 bar to damages on the basis that its transactions were not registrable, the wording of the new s.68 needs to be considered carefully before embarking on patent infringement proceedings if there is in any doubt about whether the chain of title has been registered in accordance with s.33. Under the new s.68 non-registration within the time limit means that there is a bar to recovery of costs and expenses. On the strict wording of new s.68 this bar is not limited to costs relating to infringements carried out during the period of non-registration. This is broad enough to cover all costs and expenses of the proceedings. To avoid falling prey to this provision, if there are a series of assignments that have not been registered, one practical solution may be to re-assign the patent (together with all accrued rights) intra-group and register that assignment prior to commencement of any infringement proceedings. Other safeguards should also be explored before embarking on the litigation