WASHINGTON (AFP) - The US Supreme Court on Tuesday (Dec 6) tossed out a US$399 million (S$566 million) patent award from Samsung over copying Apple's iPhone design, sending the case back to a lower court.

The justices ruled 8-0 that Samsung should not be required to forfeit the entire profits from its smartphones for infringement on design components, in a case closely watched by the tech industry.

The 11-page ruling found that the US$399 million penalty - one element of a major patent infringement case - was inappropriate because it represented "Samsung's entire profit from the sale of its infringing smartphones" for copying the iPhone's "rectangular front face with rounded edges and a grid of colorful icons on a black screen."

But the court stopped short of delving into details of the degree to which the patent infringement should affect the penalty.

"The parties ask us to go further and resolve whether, for each of the design patents at issue here, the relevant article of manufacture is the smartphone, or a particular smartphone component," Justice Sonia Sotomayor wrote in the opinion.

"Doing so would require us to set out a test for identifying the relevant article of manufacture ... and to parse the record to apply that test in this case."

The court sent the case back to the appellate court in Washington to resolve the details of the case.