The US Supreme Court will not hear Microsoft's appeal in a lawsuit that has resulted in a preliminary jury verdict of more than US$500 million for alleged patent infringement in Internet Explorer.

The court's decision not to hear the case involving Eolas Technologies, announced without comment on Monday, clears the way for proceedings to continue before a federal district judge.

The August 2003 decision from a federal jury in Chicago sent shock waves across the Internet. If Eolas and its business partner, the University of California, eventually prevail, the effects could force a redesign of Web pages that use plug-in applications like Macromedia Flash and Adobe Acrobat that run inside a Web browser.

In subsequent attempts to convince Congress to reform federal patent laws, Microsoft has cited the Eolas case as an example of "abusive litigation" that should be curbed by legislative action.

A federal appeals court in March partially reversed the original decision and sent it back to the district judge for a new trial.

Microsoft hopes that this time it will be able to show evidence about an early Web browser, called Viola, created by a computer programmer and artist named Pei Wei and demonstrated to other researchers a year before the University of California filed for its patent. The university and its spinoff company, Eolas, share the rights to a patent that they claim covers plug-ins and applets that are invoked through a Web browser.

Eolas' patent, numbered 5,838,906 and granted in November 1998, discusses a way to execute a program on a remote server and send data back to a Web browser, "thus providing the user of the client computer with interactive features."