The US ITC has said that that they are set to probe some 30 companies including Sony for the alleged breaches.

The commission said on its Web site on Thursday that the products involved are short-wavelength light-emitting diodes and laser diodes used in such electronics as handheld mobile devices, traffic lights and high-definition DVD players.

The move is based on a complaint filed in February by Columbia University Professor Emeritus Gertrude Neumark Rothschild, who is seeking to block imports into the United States of a range of products that she said were infringing her patent.

Besides Sony, companies cited in the ITC announcement include Nokia, Motorola, LG Electronics, and Panasonic maker Matsushita Electric Industrial Co Ltd

A Sony spokesman said the consumer electronics maker could not as the investigation is ongoing.