Compact discs could be history within five years, superseded by a new generation of fingertip-sized memory tabs with no moving parts.

Scientists say each paper-thin device could store more than a gigabyte of information - equivalent to 1,000 high quality images - in one cubic centimetre of space.

Experts have developed the technology by melding together organic and inorganic materials in a unique way.

They say it could be used to produce a single-use memory card that permanently stores data and is faster and easier to operate than a CD.

It's claimed that turning the invention into a commercially viable product might take as little as five years.

The card would not involve any moving parts, such as the laser and motor drive required by compact discs. Its secret is the discovery of a previously unknown property of a commonly used conductive plastic coating.

US scientists at Princeton University, New Jersey, and computer giants Hewlett-Packard combined the polymer with very thin-film, silicon-based electronics.

The device would be like a standard CD-R (CD-recordable) disc in that writing data onto it makes permanent changes and can only be done once. But it would also resemble a computer memory chip, because it would plug directly into an electronic circuit and have no moving parts.

A report in the journal Nature described how the researchers identified a new property of a polymer called PEDOT.

PEDOT, which is clear and conducts electricity, has been used for years as an anti-static coating on photographic film. Researchers looked at ways of using PEDOT to store digital information. In the new memory card, data in the form of ones and zeroes would be represented by polymer pixels.

When information is recorded, higher voltages at certain points in the circuit grid would "blow" the PEDOT fuses at those points. As a result, data is permanently etched into the device. A blown fuse would from then on be read as a zero, while an unblown one that lets current pass through is read as a one.