29 Aug 2002
Japanese companies NEC and Toshiba suggest a blue-laser DVD format that will allow backward-compatible players.
Unlike the Blu-Ray disc format, which was proposed by nine other electronics companies in February, the new proposal will use current disc-manufacturing technology and allow next-generation DVD players to play today's discs.
"This will minimize the investment required for the transition of next-generation DVD, bringing benefits to hardware and software developers, manufacturers and consumers," said the companies in a joint statement.
Toshiba, which was one of the first companies to comercialize DVDs, was notably absent from the Blu-Ray consortium.
As with Blu-Ray, NEC and Toshiba propose that the high-capacity discs use a 405 nm laser diode. But while the Blu-Ray proposal includes a 0.1 mm-thick optical transmittance protection layer, NEC and Toshiba's technology does not include this. The new proposal also uses a smaller objective lens, with a numerical aperture of 0.65 compared with Blu-Ray's 0.85.
NEC and Toshiba's format will increase the capacity of read-only DVD from 8.5 GB to 30 GB for a single-sided, dual-layer disc. The companies also say that they will shortly propose rewritable discs with a capacity of 40 GB.
The two companies have submitted their technology to the DVD Forum, an international association of hardware and software companies invloved in DVD development.
In February this year, the DVD Forum established two sub-groups to study different approaches toward developing next-generation DVD. One group is researching a technique that uses a 0.1 mm cover layer. The second, like NEC and Toshiba, is considering an approach based on the standard 0.6 mm disc substrate.
Michael Hatcher is technology editor of Opto and Laser Europe magazine.