Two years from now the world's smallest optical disc will let your cellphone store five two-hour movies, squirrel away 25,000 digital photos or hoard 48 hours of MP3 music.
New Scientist has learned that the electronics company Philips has been secretly researching the technology in Britain at its research centre in Southampton. It uses a miniature optical disc that records, plays back and erases data using the same precision blue lasers that are being developed for the next generation of high-definition video recorders.
The Philips disc has no catchy name yet, so the system is known as SFFO, short for Small Form Factor Optical. In Japan last week, Philips demonstrated SFFO discs to convince sceptics that it really is possible to store four gigabytes on a three-centimetre disc, and to make a drive as small as a memory card that can read it reliably.
SFFO spun off from Philips's work on Blu-ray, the emerging standard for a system that will use blue lasers to record high-definition TV pictures on DVD-sized discs. Blu-ray is backed by a group of leading firms, including Panasonic, Pioneer, Philips, Samsung, Sharp and Sony.
The three-centimetre disc will be the same thickness as a DVD, but the phase-change material that records the data will be a mere 0.1 millimetres thick, compared to 0.6 millimetres for DVDs. Philips says this should mean there is less risk of beam distortion if the disc tilts when the portable device gets jogged. Portable DVD players will not play smoothly if jogged.
This jog-resistance is helped by making the glass and polymer lens that focuses the laser only 1.3 millimetres wide, just one-third the size of the lens in a DVD recorder. This means the optics need be only one-tenth the mass of their counterpart in a DVD, light enough for an electromagnet to keep them steady.
The drive is currently 0.5 centimetres thick, 5.6 centimetres long and 3.4 centimetres wide. The first versions of the disc will store one gigabyte on each side, but the dual-layer coating already used for DVDs will double the capacity to four gigabytes in total.
Wayne Fletcher at Philips's Southampton lab says SFFO will be ready for sale in two years. Chris Buma, who heads Philips's optical division at Eindhoven in the Netherlands, says discs can be made for "a few cents". The drives will initially cost around £70 but this is expected to fall.
Philips says it was "just coincidence" that DataPlay of Colorado, US, a firm offering a rival micro disc technology, hit a cash crisis just as Philips decided to come clean about its SFFO technology. DataPlay is designed to record just 250 megabytes per side of a 3.2-centimetre disc, but so far without the option to erase and reuse the disc.