The US Patent and Trademarks Office (USPTO) has issued a preliminary ruling that an Eolas patent on browser technology allegedly infringed by Microsoft’s Internet Explorer (IE) is invalid.

Eolas last year won a court victory, when a US jury ordered Microsoft to pay $520.6m in settlements for infringing the patent. Microsoft lodged an appeal, and claimed the patent would force it to change the way IE processes web page plug-ins.

World Wide Web Consortium (W3C) director Tim Berners-Lee subsequently called on the USPTO to review Eolas’ patent, saying it could cause widespread and irreparable harm to the web and innocent users. Berners-Lee said object embedding technology has been part of the HTML standard since the earliest days of the web.

A USPTO spokesperson said yesterday because prior art existed in this case, it had prompted a director ordered re-examination of Eolas’ patent. The patent is now undergoing re-examination, in a process that can take up to 21 months. Eolas has 60 days to refute the preliminary findings.

The USPTO said in 19% of cases, disputed patents are found unpatentable in director ordered re-examinations, while 13% are upheld. In 68% of cases, one or more elements of a claim are changed.

This article is based on material originally published by ComputerWire