NEC shows prototype dual DVD/HD-DVD drive

NEC has demonstrated for the first time a prototype optical disc drive that uses a single optical head to read DVDs and discs recorded in a blue-laser format that is awaiting final approval as the next-generation DVD standard.

Conventional DVDs require the use of a red laser to read and write data from the disc, while the next-generation format makes use of a blue laser to do the same job. It's this laser that is one of the keys to the greater storage capacity of High Definition and High Density DVD (HD-DVD). However, it can't be used to read current DVDs so future optical disc players won't be able to read both kinds of disc without the development of a combined optical head.

The drive demonstrated by NEC on Thursday at a Tokyo news conference was only capable of reading data, but the company said the same technology could be used to make a read/write head.

Development of a common head for both DVD formats is only one of a number of steps that needs to be taken before such drives begin appearing in products. At present the largest hurdle remaining is the ratification of the format itself, said Hiroshi Inada, senior manager of NEC's optical recording technology center, in an interview following the demonstration.

NEC and Toshiba Corp. jointly developed the AOD (Advanced Optical Disc) system and recently submitted it to the DVD Forum for approval as a next-generation DVD format. Discussions towards final approval of the format are currently under way and version 0.9 of the format has been approved. It specifies a 20G-byte rewritable disc and read-only discs in two capacities: 15G bytes in a single layer or 30G in two layers.

NEC is continuing to work on the optical head, enabling a data recording function and expanding its compatibility to include CDs, which use a red laser of a different frequency to DVD. An optical head compatible with CD, DVD and HD-DVD and capable of both read and write operations is expected to be developed in the first half of next year, Inada said.

Work on a recordable (write-once) version of HD-DVD is also under way, he said.