Battle intensifies over blue LEDs and violet lasers
By Paul Kallender and Yoshiko Hara , EE Times
May 16, 2001 (1:17 PM)
URL: eetimes.com
TOKYO — Rohm Co., Nichia Corp. and Cree Inc. are engaged in an intensifying round of patent-infringement disputes in the United States that underscore the anticipated growth in demand for gallium-nitride devices — blue LEDs and violet lasers.
Last December Rohm (Kyoto, Japan) filed a complaint before the International Trade Commission (ITC) and the United States District Court for the Eastern District of Pennsylvania, claiming that Nichia had infringed on its blue LED-related patents. Although Rohm has now filed a motion before the ITC to withdraw that complaint, the company has vowed to fight on in separate litigation.
"It is very rare for a litigant to withdraw like this," said Kiyoshi Komatsu, a sales manager at Nichia in Japan. "We'd also like to ask them why they did it," he said.
In rebuttal, a Rohm spokesman in Kyoto said the "ITC's investigation rather focuses on how to protect domestic industries, but we want to focus on the patent issue to make the infringement clear."The spokesman added, "We want to resume the investigation in Pennsylvania as early as possible." But Pennsylvania has suspended its investigation while it waits for a ruling from the ITC.
Komatsu of Nichia, however, said the withdrawal significantly strengthens Nichia's position as both Nichia and Rohm, together with Cree (Durham, N.C.) vie to carve out positions in the growing gallium-nitride semiconductor diode market.
Nichia has more than a 50 percent share of the global half-billion-dollar gallium-nitride-based LED market, Komatsu said. While that market amounted to $572 million in 2000, it is due to nearly triple in size to $1.4 billion in 2005 and to reach $2.3 billion by 2009, according to research by market analyst firm Strategies Unlimited. "We were strong before and this shows our strength," said Komatsu.
"We believe the motion to withdraw removes any doubt that the ITC complaint was frivolous and that manufacturers in the United States will have ongoing access to Nichia's LEDs," said Noboru Tazaki, manager-director and general manager of Nichia's Optoelectronics Products Division. "This turn of events also eliminates concern over the availability of violet and blue laser diodes in the United States," he added, claiming that Nichia is the world's only supplier of those products.
Blue LED claims
Rohm, on the other hand, has been sending warning letters for about two years to Nichia, claiming that Nichia is infringing on Rohm's patents on blue LEDs, said the Rohm spokesman. "We proposed to Nichia a cross-licensing contract. It is ideal to expand the market, because blue LEDs cannot be made without Nichia's patents. But we have not received an affirmative answer," said the Rohm spokesman. Thus, the company took action in the United States first to clarify the patent-infringement issue, he said.
The new round of disputes began last Dec. 15, just after Rohm agreed to form a technical alliance with Cree to jointly develop gallium-nitride (GaN) blue LEDs and violet lasers, merging Rohm's device structure design and Cree's silicon-carbide (SiC) substrate technology. As part of the deal, the two companies signed a five-year exclusive licensing agreement granting Cree rights to Rohm's U.S. LED and semiconductor laser patents.
The fight began last September, however, when Cree, together with North Carolina University, sued Nichia, claiming that Nichia was infringing on its lateral epitaxial overgrowth (LEO) technology. The U.S. Patent No. 6,051,849, entitled "Gallium Nitride Semiconductor Structures Including a Lateral Gallium Layer That Extends From An Underlying Gallium Nitride Layer," was issued to North Carolina State University in April 2000 and was licensed to Cree exclusively.
Shuji Nakamura, who was Nichia's chief researcher before he left in 1999, reported in his thesis that "an epitaxially laterally overgrown GaN (Elog) technology" played the key role in generating a defectless substrate and enabled Nichia's diodes to clear the 10,000-hour life milestone in November 1998. A decision on whether LEO and Elog are the same technology has yet to be reached. Elog technology has been used in Nichia's laser diodes since then.
Rohm joined the battle last December to protect Cree's rights as the exclusive licensee of Rohm's patents. Rohm took a double-barreled approach, filing patent-infringement lawsuits against Nichia and Nichia America Corp. before the ITC and the United States District Court for the Eastern District of Pennsylvania.
The patents cover technologies used to generate the clad layers of optical devices in adequate thicknesses. GaN blue LEDs and violet laser diodes use those technologies to emit high-power light with low voltage, according to Rohm.
On Dec. 21, 2000, Nichia countered by filing a suit in the U.S. District Court for the Eastern District of North Carolina against North Carolina State University, Cree and Nakamura.
Nakamura is currently a professor in the Materials Department at the University of California, Santa Barbara. In addition to his duties as a professor, last November Nakamura signed on as a part-time researcher with Cree Lighting Co., a Cree subsidiary.
Nichia's countersuit charged all three parties with patent infringement and trade secret theft. The patents and trade secrets cover methods of manufacturing and design for GaN-based LEDs, laser diodes and electronics, according to Nichia.
Nichia's countersuit focused especially on Cree's employment of Nakamura, which led to the "inevitable" disclosure of trade secrets by Nakamura to Cree. Nichia asserted that Cree hired Nakamura because of his knowledge, which had been acquired during his 20 years at Nichia.
Nichia's patent portfolio
Nichia has in its portfolio an overwhelming number of patents covering blue LED and violet laser technology. Nakamura developed the GaN-based devices when he worked as Nichia's chief researcher.
Nichia, which had been a manufacturer of phosphor materials, used Nakamura's developments to successfully diversify into the optoelectronic device business, which became its mainstay. When Nakamura left the company, Nichia retained ownership of all of the patents connected to his research.
The media reported that Nichia's conservative management did not give Nakamura enough incentives in spite of his impressive achievements, and Nakamura did not refute those reports.
While Nichia acknowledged that Nakamura's contributions made the company the world leader in GaN-based devices, it asserted that Nakamura was working on Nichia's behalf as an employee, and was provided with the money, facilities and materials to do so. Further, the company claims that he is still bound by the nondisclosure contract he signed when he first joined the company in 1979. |
