A federal judge on Friday erased nearly half of the $1 billion in damages that a jury decided that Samsung Electronics should pay Apple in a high-profile trial over the smartphone and tablet computer patents.

U.S. District Court Judge Lucy Koh lowered the damages awarded to Apple Inc. by $450.5 million, saying jurors had not properly followed her instruction in calculating some of the damages. The ruling reduced Samsung Electronics' bill to just under $599 million.

Koh also ordered a new trial on Apple's allegations that Samsung stole its ideas for more than a dozen different smartphones and tablet computers.

The jury decided last year that Samsung ripped off the innovative technology used by Apple to create its revolutionary iPhone and iPad and ordered Samsung to pay Apple $1.05 billion in the latest skirmish of a global legal battle between the two tech giants.

Apple filed its patent infringement lawsuit in April 2011 and engaged legions of the country's highest-paid patent lawyers to demand $2.5 billion from its top smartphone competitor. Samsung Electronics Co. fired back with its own lawsuit seeking $399 million.

The jury found that several Samsung products illegally used such Apple creations as the "bounce-back" feature when a user scrolls to an end image, and the ability to zoom text with a tap of a finger.

The case is ultimately expected to land before the U.S. Federal Circuit Court of Appeals, the Washington-based court that decides patent disputes, if not the U.S. Supreme Court.

Nonetheless, Koh is expected to greatly shape the end result.

Samsung has mounted an aggressive post-trial attack on the verdict, raising a number of legal issues that allege the South Korean company was treated unfairly in a federal courtroom a dozen miles from Apple's Cupertino headquarters. Samsung alleges that some of Apple's patents shouldn't have been awarded in the first place and that the jury made mistakes in calculating the damage award.

Samsung has emerged as one of Apple's biggest rivals and has overtaken as the leading smartphone maker. Samsung's Galaxy line of phones run on Android, a mobile operating system that Google Inc. has given out for free to Samsung and other phone makers.

Apple and Samsung have filed similar lawsuits in eight other countries, including South Korea, Germany, Japan, Italy, the Netherlands, Britain, France and Australia.