Apple, Sony and four other companies were sued by Graphics Properties Holdings Inc, formerly known as Silicon Graphics, for allegedly infringing a patent through their sale of mobile phones and other electronic devices.

The has claimed that the technology firms have infringed patents for a process that turns text and images into pixels displayed on screens.

The defendants are Apple, Samsung, Sony, LG Electronics, HTC and Research in Motion (RIM).

A letter written by GPH's lawyers to the US International Trade Commission (ITC) says the dispute centres on three patents filed in February 1998, November 2003 and November 2004.

The documents discuss a "hardwired supercomputer data processing apparatus" - a graphics program designed to improve the quality of images shown on a screen, and a wide aspect ratio LCD screen with a high resolution display.

According to the lawsuits, the devices that infringe GPH's intellectual property include the Apple iPhone; the LG Thrill; the HTC EVO4G; the Blackberry Torch and PlayBook; the Samsung Galaxy S and S II; and the Sony Xperia Play.

Silicon Graphics filed for bankruptcy in 2009.

RIM's representatives wrote to their letter to ITC: "The Blackberry Torch and PlayBook devices provide a combination of features that may not be available on any competing product and are essential for certain public interest applications, including security and medical applications. Accordingly, any exclusion of RIM's accused devices will adversely affect public health, safety, and welfare in the United States."

Apple's submission said: "This broadly worded scope of GPH's proposed investigation reaches numerous devices and components, most of which have no connection to the asserted patents.To the best of Apple's knowledge, GPH neither develops nor manufacturers any product, including any product that competes with the devices that would be subject to any exclusion order."

"Across all of the patent claims sought to be asserted by GPH against all of the proposed respondents, the only product categories for which specific alleged unfair acts are detailed are smartphones, tablet computers, and televisions containing LCD panels with wide aspect ratios," Samsung said. "The currently-requested investigation, however, would reach not only products in those categories but the far broader universe of 'Consumer Electronics And Display Devices And Products Containing Same'", the Korean company added.