First published in EPLAW, January 2020
This case was brought by the patentee, Technetix B.V and two licensees (the “Claimants”) against Teleste Limited (the “Defendant”), a company which manufactures electronic components. The Claimants alleged infringement of European Patent (UK) No. 1,259,079 B8 (“EP’079”) and the Defendants counterclaimed for revocation of the same patent. The Claimants did not seek to uphold the claims as centrally amended, instead making an unconditional application to amend along with a further conditional application to amend if required (the “Unconditional Claims” and “Conditional Claims” respectively).
Hacon HHJ, sitting as a judge of the High Court, held that both the Unconditional Claims and the Conditional Claims would be invalid, but that had the Unconditional Claims been valid, they would have been infringed by all three of Teleste’s products in issue.
EP’079 relates to the reduction of the generation of intermodulation products (a form of signal distortion in a cable network), thereby reducing the signal-to-noise ratio. Intermodulation products are generated when a ferrite component in a system is “saturated” (the voltage across the component ceasing to increase when a magnetising force is applied). This causes the relationship between output and input across the components to become non-linear. Saturation occurs when the ferrite component is subject to a “voltage peak” (also described as a transient energy peak) such as those caused by lightning or equipment connected to the network.
The production of intermodulation products is reduced in EP’079 by filtering out signals with a frequency below a certain cut off using a “high-pass filter”.
The characterising part of both Unconditional and Conditional claim 1 requires the high-pass filter to comprise an “LC-filter” (L and C standing for inductor and capacitor respectively) including at least one coil and one capacitor. Conditional claim 1 also includes the requirement that the LC-filter comprises two 1nF capacitors and a 3.3µH coil.
The Claimants alleged infringement of three of the Defendant’s products. The Defendant accepted that two of the three products fell within both the Unconditional and Conditional Claims, but disputed that the third product infringed the Unconditional Claims (it was not alleged to infringe the Conditional Claims).
The Defendant’s units contained “inductor first” LC-filters, which the Defendant argued were not high-pass filters within the meaning of claim 1. Hacon HHJ held that the evidence from both sides’ experts on this matter was difficult to follow and in any event addressed different points. He did not consider that either expert properly addressed the main issue of whether an inductor first filter “at least partially” prevented the generation of intermodulation products.
However, on the evidence in front of him, Judge Hacon held that even if the inductor first filter did not completely filter out the low frequency signals, it would still have the effect of “at least partially” preventing the generation of intermodulation products (he considered this was not a high hurdle to meet) and that therefore the third device did contain a high-pass filter within the meaning of claim 1 of both sets of claims.
The Defendant had also applied for a declaration of non-infringement of the Conditional Claims in relation to two hypothetical products. However, this declaration was abandoned during trial.
The Defendant alleged the Unconditional Claims lacked novelty over a US patent: US 5,390,337 (“Jelinek”). It also argued that both the Unconditional and Conditional Claims lacked inventive step over three pieces of prior art: Jelinek; a conference paper presented in May 2000 (“Mothersdale”); and another paper published in May 1999 (“Buie”).
The Judge first considered novelty of the Unconditional Claims over Jelinek. Jelinek concerned the use of a high-pass, LC, filter in amplifiers used in cable TV networks. One of the roles of the LC filter was to prevent high energy burst signals from reaching the amplifiers. It was common ground that the amplifier being protected would contain a ferrite component. The only integer not disclosed in Jelinek was the express prevention of intermodulation by the LC filter.
On the evidence before him, Judge Hacon considered that, contrary to the Defendant’s case, the link between transient energy peaks being applied across the ferrite and the consequential production of intermodulation products would have been known to the skilled person. But in any event, this did not matter, since the use of Jelinek’s LC filter to protect against the energy peaks would result in the reduction of intermodulation and therefore the Unconditional Claims lacked novelty over Jelinek (following Synthon BV v SmithKline Beecham plc.  UKHL 59).
Hacon HHJ also held the Conditional Claims to be invalid over Jelinek for lack of inventive step. The only additional feature in the Conditional Claims was that the LC filter comprises two 1nF capacitors and a 3.3µH coil. Hacon HHJ held that there was no evidence of there being any particular advantage in using inductors and capacitors with these particular characteristics and therefore the selection was arbitrary and lacking inventive step (following LG Philips LCD Co Ltd v Tatung (UK) Ltd  EWCA Civ 1774).
The Unconditional and Conditional claims were also found to lack inventive step over the two other pieces of prior art, Mothersdale and Buie. The Judge agreed with the Defendant’s broader interpretation of the disclosure of Mothersdale and Buie as the use of a blocking capacitor as a general high-pass filter to reduce intermodulation (addressing both AC and DC signals).
The Defendant argued that the skilled person would test these systems before deploying them and that if an improvement were required, it would have been obvious to use a higher order filter. Hacon HHJ agreed. He held that it was common general knowledge that an LC filter was an example of such a higher order filter, and that an LC filter would have been an obvious replacement for the blocking capacitor. This meant that the Unconditional Claims were invalid for lack of inventive step over both Mothersdale and Buie. The Conditional Claims were held to be invalid for lack of inventive step for the same reasons as in relation to Jelinek.
The final invalidity argument run by the Defendant was an added matter argument on the Conditional Claims. The Defendant argued that the additional features inserted into Claim 1 of the Conditional Claims had been taken out of the specific context in which they had been disclosed in EP’079 and therefore constituted an impermissible intermediate generalisation. Hacon HHJ agreed; he saw no reason why the skilled person would understand the disclosure of the two 1nF capacitors and a 3.3µH coil in a specific embodiment of the invention to be an exemplary disclosure of a wider class of systems.
The judgment can be found here.