Credit: Reuters/Dado Ruvic
Men are silhouetted against a video screen with an Samsung logo as they pose with an Apple iPhone 4 smartphone in this photo illustration taken in the central Bosnian town of Zenica, May 17, 2013.
The three-judge panel questioned whether Apple should or could be required to prove that one feature of a product such as a smart phone is the driver of consumer demand for that product.
The Federal Circuit last year rejected Apple's request for a pretrial sales ban against Samsung's Galaxy Nexus phone.
The case is Apple Inc v. Samsung Electronics Co Ltd, Federal U.S. Circuit Court of Appeals, No. 13-1129.
(Reporting by Alina Selyukh; Editing by Ros Krasny and Vicki Allen)
