English High Court: Sony Communications International AB v SSH Communications Security Corporation

Background

Recent experience in the UK Patents Court has shown that the validity of patents for genuine inventions in the telecommunications field will be upheld and infringement found. Patents for merely the obvious will be revoked. In the SSH case, Sony evidently took the view that European Patent (UK) to 2 254 311 ("EP 311") fell into the latter category. Sony commenced an action seeking revocation in the UK court. EP 311 had a priority date of 1999 and related to an aspect of accessing wide area networks, such as the internet and was particularly concerned with ensuring the Internet Protocol Security protocol suite could be used reliably and securely through a Network Address Translator (intermediate nodes acting as gateways between a private network and e.g. the internet).

Sony's claim prompted SSH to counterclaim for infringement, alleging that certain Sony Xperia devices infringed EP 311. As is usual in the UK, the claim for revocation and the infringement counterclaim were tried at the same time.

On 10 October 2016, the English Patents Court (Roger Wyand QC, sitting as a Deputy High Court judge) gave judgment in the case. It illustrates two particular aspects of UK patent litigation; (1) amendment during litigation; and (2) the approach to obviousness arguments based on common general knowledge alone.

Amendment during litigation

In the UK, the court has power, in infringement and revocation proceedings, to allow amendments to the patent in suit. The patentee thus has the opportunity, subject to the usual principles about basis and clarity, of seeking to frame a revised claim that, on the one hand, better distinguishes the invention from the prior art but, on the other, still catches the alleged infringement. The amendments can be either conditional (i.e. the patentee intends to defend the claims as granted) or unconditional. The allowability of the amendments (whether or not they add matter, are clear and/or cure any invalidity) will be decided at the same time as the main trial. In the case of amendments that involve a rewriting of the claims (e.g. an insertion of wording from the description), it is important from the patentee's perspective that proposed amendments are tabled in a timely manner and it is not left too late.

Here, SSH put forward three sets of conditional amendments in the proceedings, the first introducing limitation into all the claims that corresponded with these specific embodiment of EP 311, the second adding...