A U.S. judge asked that the chief executives of Apple Inc and Samsung Electronics Co Ltd speak to each other at least once on the phone before a jury begins deliberating next week in the high-stakes patent trial between the two tech giants.

"It's time for peace," U.S. District Judge Lucy Koh said on Wednesday in a San Jose, California, federal court, just miles from Apple's headquarters.

Apple and Samsung are going toe-to-toe in a patents dispute mirroring a struggle for industry supremacy between the two rivals that control more than half of worldwide smartphone sales.

Apple accuses Samsung of copying the design and some features of itsiPad and iPhone, and is asking for a sales ban in addition to monetary damages. South Korea's Samsung, which is trying to expand in the United States, says Apple infringed several patents, including some for its key wireless technology.

The U.S. trial is now in its third week. Before the jury was brought into the courtroom on Wednesday, Koh told attorneys for the companies that they had succeeded in raising awareness about the importance of their intellectual property rights.

Top executives from both companies had participated in mediation with a U.S. magistrate judge before trial, but Koh asked them to explore settlement once again.

The nine-member jury is scheduled to begin deliberations next week.

"I see risks here for both sides," Koh said.

The case in U.S. District Court, Northern District of California, is Apple Inc v. Samsung Electronics Co Ltd et al, No. 11-1846.