KYOTO -- Kyoto-based Rohm Corp., one of Japan's largest makers of electronic components, is locked in a legal wrangle with Nichia Corp. of Anan, Tokushima Prefecture, over patents related to blue light-emitting diodes and blue lasers.

Blue LEDs and blue lasers constitute two of the most important electronic breakthroughs of the past decade.

Rohm filed suit in the Kyoto District Court on July 2, claiming Nichia had infringed on a patent related to blue LEDs that Rohm has started supplying to firms that include Sony Corp. and Matsushita Electric Industrial Co.

The suit is the latest in a series of recent legal steps taken by Rohm, Nichia and other firms in Japan and the U.S.

The firms are jockeying for position prior to the mass-marketing of products ranging from cellphone displays to digital video discs that incorporate these technologies. But the suits may delay the arrival of DVD players that can record up to 10 hours of video and audio information by months, sources said.

Although Rohm and Nichia have discussed cross-licensing patents -- most of which are held by Nichia -- the latter has staunchly refused to share patents that it feels are fundamental to its trade.

LEDs emit noncoherent light and are used mainly in electronic equipment displays and indicators. Lasers emit coherent light and have a very narrow beam.

Blue lasers are much narrower than red lasers, and thus can carve out more information on smaller media.

Currently, no DVDs on the market feature blue lasers, according to Bob Thompson of Nichia America.

"In most cases, the technology (for blue lasers and LEDs) is proprietary now as people are trying to determine the appropriateness and longevity of the devices, meaning how long they function in various environments," he said.

"Therefore, we can't project how long it will take before, for example, DVDs incorporating blue lasers will reach the marketplace."

Blue LEDs and lasers were invented in Nichia's labs in 1993 by Shuji Nakamura, then the firm's chief engineer. Using a catalyst of Gallium nitride (GaN), which was considered a dead end by many at that time, Nakamura was able to produce a constant blue light at room temperature that was as bright as emissions in the red spectrum.

With other larger companies having long sought to achieve this landmark breakthrough, Nichia has since filed more than 100 patents related to Nakamura's work.

In 1999, Nakamura abruptly left Nichia, claiming to be dissatisfied with the constraints his employers had imposed on him and their lack of recognition of his achievements.

He is now a professor at the College of Engineering at the University of California at Santa Barbara and a consultant for Cree Inc., a U.S.-based manufacturer of semiconductor materials that entered into a technical alliance with Rohm last year.

Nakamura has been named in a separate lawsuit that Nichia has brought against Cree and North Carolina State University. Nichia claims he has revealed trade secrets to its competitors. Nakamura said, however, that he has not yet been asked to submit documents in the case and has not been called to testify.

In the most recent suit filed, Rohm asserts that Nichia has violated its patent on technology that reduces the power used by LEDs by 10 percent.

A similar suit was filed by Rohm against Nichia in the U.S. last year but was withdrawn on June 18 after an unfavorable ruling by the International Trade Commission.

The ITC is now investigating Rohm at Nichia's behest over a possible breach of U.S. antitrust legislation.

"The market for blue laser and LED applications will be in the billions of dollars," said Gerhard Fasol, president of Eurotechnology in Tokyo and coauthor a book on blue lasers with Nakamura.

"These lawsuits are very expensive. People are spending on these lawsuits because the money involved is far bigger," he said.

Rohm and Nichia declined comment on the pending suits, which may delay the release of their most recent LED products, originally planned for this summer.

The delay comes at a time when Rohm and other Kansai-based high-tech firms have had to revise their earnings forecasts downward.

Last month, Rohm announced that its orders had fallen 22 percent due to a continuing slump in demand for electronic products. This contrasts sharply with last year, when the electronics giant posted record profits.