Nichia Corp., a supplier of such gallium-nitride devices as blue LEDs and blue lasers, has waived its worldwide rights under the so-called 404 patent.

Once deemed essential for blue-LED production, Japan's patent No. 2628404 was at the center of a high-profile dispute between Nichia and Shuji Nakamura, a onetime Nichia engineer who developed the first brightly shining blue LED in 1993. Nakamura left in 1999 and later became a professor at the University of California-Santa Barbara.

The 404 patent covers Nakamura's metal-organic chemical-vapor deposition system, which employs both horizontal and vertical gas flow. In the early '90s, it was difficult to grow quality GaN crystal on a sapphire substrate with a lattice constant different from that of GaN. Nakamura called his system the key to growing high-quality GaN crystals for long-life, bright-blue LEDs.

Nakamura and Nichia fought in the courts over the patent and ultimately settled on Nichia's paying $5 million to Nakamura as compensation for the all patents, including 404, in which he had been involved.

Why did Nichia renounce its patent right to 404 only a year after the court settlement? Katsuyuki Akutagawa, general manager of Nichia's intellectual-property department, said neither the company nor any licensee still uses it. To maintain patent rights on 404 would have cost Nichia about $44,000 by the time it expired in 2010. So Nichia decided to waive its rights, Akutagawa said.

While Akutagawa said the two-flow MOCVD system is unsuited for volume production and is no longer used, he acknowledged it was part of blue-LED production in the early phase, from 1993 to 1997.

Nichia, not surprisingly, downplays Nakamura's role, arguing that many engineers and other staffers worked to develop the blue LED and build up the GaN business. Nonetheless, Gen-ichi Shinomiya, managing director of Nichia, acknowledges it was Nakamura who selected GaN for LEDs. In the early 1990s, selenide was seen as the mainstream solution, with GaN a minor candidate. Nakamura opened the door to GaN, and Nichia's brightly emitting GaN devices changed the flow of R&D from selenide to GaN. Indeed, thanks to GaN, Nichia boosted sales more than 10 times in 12 years since 1993.

The court settlement ceded all patents to Nichia but allowed Nakamura to build on knowledge gained on the job at Nichia. Nakamura has since announced a structure for GaN devices with the potential to enable white LEDs with luminous efficiency as high as 200 lumens per watt, or more than double that of today's fluorescent lamps. Nichia has developed a white-LED device at 100 lumens/W, which equals or exceeds the figures for existing fluorescents. Sales will begin by year's end.

In the end, technology prevails. Brightly emitting blue LEDs enabled new applications and continue to illuminate people's lives.