Sanyo Electric Co., Ltd. announced that it developed new blue-violet semiconductor laser diodes with improved light-emission characteristics. According to Sanyo, the laser can realize stable light emission characteristics and low price, which have been required for next generation DVDs.
The blue-violet semiconductor laser has a shorter wavelength than that of the red semiconductor lasers that are used for the current DVD reading/writing. As the laser light wavelength becomes shorter, the bit spot generated by the laser on the surface of CD/DVD discs can be made smaller in its size.
Regarding the CD/DVD recording, the capacity of data recording on a CD/DVD disc depends on its recording bit size. If the recording bit spots are smaller, capacity of data can be recorded more on the CD/DVD discs.
The new technology, the company said, will realize next-generation DVDs to have capacity as large as five to six times the current DVDs. So far, the blue-violet lasers developed and manufactured by other makers have unstable light emission characteristics and high manufacturing costs. Sanyo has improved these shortcomings through developing the laser elements with a new structure.
The major laser characteristics are as follows: 1) the light output power of 5mW, 2) the threshold current of 40mA, 3) the operation current of 45mA, and 4) the laser oscillation wavelength of 405nm. The laser oscillation wavelength of 405nm is the same as that of the large capacity optical disc video format "Blu-ray Disc," which was recently announced jointly by nine leading companies including Matsushita Electric Industrial Co., Ltd., Sony Corp., and others.
While it has no relation to the activities of the Blu-ray Disc standard, Sanyo said it intends to promote the lasers to the makers trying to commercialize the DVDs based on the standard. Sanyo plans to start shipping the samples during this autumn, and volume manufacturing in April 2003. At this stage, Sanyo made no comment on its costs, only added, "We hope to lower its costs to the same level of red lasers in a near future."