The defendant Glasswall (IP) is the assignee of the UK designation of a European patent concerning anti-malware software. The patent had been originally applied for by a software company called Avecho.
The validity of patent may be challenged if the invention is not novel, it is obvious, or relates to excluded subject-matter such as business methods or methods of medical treatment. Information security company Clearswift commenced a revocation action against Glasswall on the basis that a US patent application and a series of bulletin board posts constituted 'prior art' that rendered Glasswall's patent invalid for obviousness. Glasswall did not counterclaim for infringement so validity was the only issue before the court.
In considering Clearswift's case, David Stone, sitting as a deputy judge in the High Court, highlighted case law in England and Wales that sets out how allegations of obviousness should be assessed by the courts.
That case law states that judges must view the allegations through the eyes of a notional person skilled in the particular 'art' to which the patent relates and identify the relevant common general knowledge of that person.
Adopting that approach, judges must identify the inventive concept of the claim in question or if that cannot readily be done, construe it, and further identify what, if any, differences exist between the claimed prior art and the inventive concept of the claim or the claim as construed. Finally, they must establish whether, viewed without any knowledge of the alleged invention as claimed, those differences constitute steps which would have been obvious to the skilled person or if they require any degree of invention.
In his ruling, the High Court judge did not accept Clearswift's claims that the disclosure in the US patent application made Glasswall's invention obvious.
Central to that finding was the fact that Glasswall's patent was for an anti-malware programme that could be used on "different file types", whereas the US patent application did not "contemplate" that, focusing as it did on managing malware delivered via two email formats. The judge also said that the way that Glasswall's 'whitelisting' system worked to filter content was "inventive". It was different from "a whitelisting system that simply lets through all known files from a known sender", he said.
The judge then considered Clearswift's arguments about the disclosures made on the Internet bulletin board.
Clearswift’s expert witness, Alexander Shipp, was an experienced anti-malware practitioner who was granted access to Avecho anti-malware software in order to test it. He posted a summary of his findings on the bulletin board and those comments, together with six other posts all pre-dating the patent’s priority date were relied upon as prior art by Clearswift. Ultimately, the judge found that the patent was not obvious when assessed against these message board posts.
"Under UK patent law, the skilled person is assumed to take an interest in the prior art in the case, so it would not count against a document if it was obscure," said intellectual property law expert Mark Marfé of Pinsent Masons, the law firm behind Out-Law.com. "Whether, having read it the skilled person would find it useful is another matter."
"In this case the judge said the skilled person 'would have been very interested in the posts', because of the claims made about the software in Avecho’s advertising material referenced in the posts and because of the reputation of the people who wrote the posts. It would have been interesting to have seen if the court’s view would have changed if the software had been tested by more 'run of the mill' software engineers," he said.
Dr Michael Schneider, a Munich-based patent law specialist at Pinsent Masons, said that courts in Germany will also generally consider the views of a notional expert on prior art before them and whether that renders the object of a patented invention obvious.