A U.S. appeals court upheld a patent infringement finding against BlackBerry (search) e-mail device maker Research In Motion Ltd. (RIMM) Tuesday, but struck down part of the ruling and sent it back to a lower court for further proceedings.

Shares of Waterloo, Ontario-based RIM soared more than 10 percent on news that a decision had been reached, but erased those gains after the court released details of the decision. Trading was then halted.

Analysts offered widely divided opinions on whether the decision was mainly positive or negative for RIM.

The U.S. Court of Appeals for the Federal Circuit (search) said a lower court had "correctly found infringement" in the case that pitted RIM against patent holding company NTP Inc (search).

But the appeals court concluded the lower court had misconstrued the term "originating processor", which was used in several of the claims at issue, and sent it back to the lower court to determine if the verdict should be modified.

"According to legal experts that we've already consulted on this, this is a resounding victory for NTP," said one Toronto-based analyst who follows the firm.

But a second analyst said RIM would benefit because it would get a second opportunity to make its case.

"I guarantee you RIM and NTP will both claim victory or partial victory," the second analyst said.

Tim Biggam, chief options strategist with Man Financial, said the stock jumped at first because the ruling initially appeared favorable to RIM as it appeared the case will be going back to court and "in essence will be reopened."

The news spurred huge trading of RIM options. By midafternoon, roughly 50,000 calls and 44,000 puts changed hands across the six U.S. options exchange, more than three times its average daily volume, market research firm Track Data said.

"RIM options activity has been frantic," said Jeff Shaw, head options trader at Interactive Brokers Group unit Timber Hill.

Closely held U.S.-based patent holding company NTP successfully sued RIM in 2002 for patent infringement, a ruling that RIM has appealed. A U.S. court last year issued an injunction banning BlackBerry sales in the United States, but stayed that injunction pending the outcome of the appeal.

The appeal was heard on June 7 by three judges on the U.S. Court of Appeals for the Federal Circuit.