First published in EPLAW, February 2019
This case was brought by the patentee, Technetix B.V (and two licensees) claiming infringement of UK Patent No. 2,382,473 B (“UK’473”), a patent relating to cable tap units used in the distribution of signals over a cable network.
The Claimants were not seeking to uphold UK’473 as granted, but had instead made an unconditional application to amend. The Claimants accepted that only amended claim 1 was independently valid. The Defendant, a technology company which sells equipment to provide cable TV or internet signal to subscribers, argued that UK’473 (as amended) lacked novelty and inventive step over two pieces of prior art. The Defendant also raised a Formstein defence in the event that it was held to infringe under the doctrine of equivalents.
The Defendant alleged UK’473 was invalid for lack of novelty and inventive step over two US patents: US 5,058,198 (“Rocci”) and US 6,292,371 (“Toner”). In response, the Claimants argued that the skilled person would not interpret the claim in such a way that would mean it was anticipated by either Rocci or Toner. This was because such a construction would result in the claim being anticipated by the common general knowledge. The Claimants then cited Floyd LJ’s judgment in Adaptive Spectrum and Signal Alignment Inc v British Telecommunications plc  EWCA Civ 1462 to support their argument that the Court should be slow to construe claim 1 in a way that would render it anticipated by or obvious over the common general knowledge at the priority date.
Hacon HHJ disagreed with the Claimants and held that each case should be decided on its own facts. He considered Floyd LJ’s finding in Adaptive Spectrum to be more nuanced than the Claimants had suggested, and interpreted Floyd LJ as saying that the skilled person would have difficulties making any assumptions about what prior art the patentee had considered when drafting the claims. Ultimately, Hacon HHJ held that when construing a claim under normal construction, the Court should merely read the claims through the eyes of the skilled person who would have the common general knowledge in mind. Following this approach, Hacon HHJ found claim 1 to be anticipated by both Rocci and Toner.
In the event that the Claimants were correct in their construction of claim 1, Hacon HHJ then addressed inventive step over the cited prior art. In cross examination, the Claimants’ expert had conceded that it would have been obvious to modify both Rocci and Toner to remove the alleged differences between the Claimants’ construction of the claim and these pieces of prior art. Consequently, claim 1 was not inventive over either Rocci or Toner.
Turning to infringement, the alleged infringing product was referred to as the “Tap Bank”. Hacon HHJ held that the Tap Bank did not fall within the scope of claim 1 on a normal construction, as it was missing features falling under two of the integers. He therefore considered infringement under the doctrine of equivalents and found that the Defendant’s product did fall within the scope of claim 1 under the doctrine of equivalents.
The Defendant had also argued that if the Tap Bank was known in the prior art, or constituted an obvious modification of the prior art, the Defendant was entitled to a defence to infringement. Hacon HHJ referred to this as the “Formstein defence”, after the decision from the German Federal Supreme Court in which this type of defence originated. He noted that it was not just the German Courts which had developed a Formstein type defence, but explained that the Dutch had a similar defence (indicating that the principles also work in a non-bifurcated system). Similarly, he noted the principle of “ensnarement” in the US: that the doctrine of equivalents cannot be applied in such a way that it would ensnare the prior art.
In considering whether such a defence could apply under English law, Hacon HHJ went back to the long established principle in English patent law that the patentee should not be able to prevent a person from doing that which they had lawfully been doing before the patent in issue was granted (as per Lord Hoffmann in Merrell Dow Pharmaceuticals Inc v H. N. Norton & Co Ltd  RPC 76 (the “Merrell Dow principle”)). Hacon HHJ considered that a Formstein type defence could reconcile the Merrell Dow principle with the doctrine of equivalents and that he could not rule out the possibility that the UK Supreme Court or the Court of Appeal might introduce a Formstein defence into English law.
Without actually seeking to introduce such a defence, he considered the issues as though this defence could apply. He held, albeit obiter, that the Tap Bank was obvious over the common general knowledge and so, if the Formstein defence did exist under English law, it would be available to the Defendant.
The judgment can be found here.