Four consumer electronics companies, including Sony and Sanyo Electric, have settled a complaint that they were infringing a patent on semiconductors related to LEDs and laser diodes used in products such as mobile phones, billboards, Blu-ray disc players and data storage devices, according to lawyers for the patent holder.

Sony, Sanyo, Exceed Perseverance Electronic and Luck Light Electronics have settled a complaint brought by Gertrude Neumark Rothschild, an emeritus professor at Columbia University, according to the Dreier law firm, a New York firm representing Neumark Rothschild.

In February, Neumark Rothschild filed a patent complaint against 34 companies with the U.S. International Trade Commission (ITC), alleging that the companies had infringed her 1993 patent covering a method of producing wide band-gap semiconductors for LEDs and LDs in the blue, green, violet and ultraviolet end of the spectrum. In March, the ITC voted to investigate 31 of those companies.

Neumark Rothschild asked the ITC to ban imports of infringing devices.

The details of the agreements with Sony and the other companies were not made public, said Albert Jacobs Jr., a partner at the Dreier law firm. He called the settlements "amicable" and "satisfactory to both sides."

"These latest licensing agreements are important milestones in this case," Jacobs said. "Professor Rothschild made a seminal breakthrough in understanding the doping requirements necessary for the production of the blue, green, violet and ultraviolet LEDs and LDs on a commercial and efficient scale that are essential to today's consumer electronics, and highly deserves this recognition for her work."

The LED and LD market generates several billion dollars' worth of sales a year, the Dreier law firm said.

Spokespeople from Sony and Sanyo weren't immediately available for comment.

Earlier this year, Seoul Semiconductor, a South Korean maker of LEDs, and Taiwan's Everlight Electronics signed agreements with Neumark Rothschild, who conducted research in the 1980s and 1990s into light-emitting and laser diodes.

Other companies named in the ITC complaint include Hitachi, Matsushita Electric Industrial, LG Electronics, Nokia, Samsung Group and Toshiba.