Matsushita Electric Industrial Co, the world's largest consumer electronics maker, unveiled on Monday a recordable digital versatile disc (DVD) that stores 50 gigabytes of data per side -- more than 10 times the storage capacity of current DVDs. The maker of Panasonic and National brand goods said the new technology, which uses blue-laser light and a semi-transparent material that permits recording of data on two separate layers, can hold more than four hours of digital high-definition motion pictures on one side of a disc. Consumer electronics makers are eagerly developing faster-recording, higher-capacity DVD technology with hopes that DVD recorders will be among the hottest-selling consumer electronics in the years ahead, spurred in part by an anticipated take-off in digital high-definition television.

Rival Sony Corp announced in January its DVR-Blue technology that uses a blue laser to stuff 22.5 GB of data onto one side of a disc, although it has yet to be marketed commercially. Matsushita, which already markets a DVD-RAM recorder using conventional red-laser technology, gave no target date for bringing its blue-laser, dual-layer DVD products to market.

``This is essentially a recording device for digital high-definition TV, so we'll consider what to do while watching the timing of terrestrial digital broadcasting,'' Shin-ichi Tanaka, director of Matsushita's optical disc systems development centre, told a news conference.

Japan is expected to launch land-based digital broadcasting in 2003 and then steadily shift away from analogue over a seven-year period. Matsushita's new technology includes a special construction for the top recording layer so it would become no more or less transparent after recording, thus ensuring it would not interfere with the second layer.