Miniature disk packs more data

21 Jun 2002

Philips unveils a miniature optical memory device that stores 1 Gbyte of data.

Philips has developed an optical disk drive that uses a blue laser diode to store 1 Gbyte of data on a 3 cm diameter disk.

The Netherlands-based electronics giant plans to use the technology in portable devices such as digital cameras, personal digital assistants and mobile phones.

The device's storage capacity, 1.5 times that of standard 10 cm CD-ROMs, means that it will be able to store thousands of high-resolution digital images or digital music files.

Philips says that the 5.6 x 3.4 x 0.75 cm sized prototype drive has already successfully played back MP3 music data in tests. The firm intends to make the drive even smaller in the future.

Unlike conventional optical disk drives, the Philips invention uses a plastic lens rather than a glass optic to focus the blue laser beam onto the disk. According to Philips, the plastic component is the smallest objective lens ever used for blue-laser recording and allows a reduction in the height of the drive from 12.5 to 7.5 mm.

Coen Liedenbaum, who has led work on the drive at Philips, said that the key development was configuring the lens to reduce the laser beam diameter, thus allowing more information to be squeezed onto the disk.

The device, which employs a Nichia laser emitting at 405 nm, works in read-only mode at the moment. However, Liedenbaum told Optics.org: "The plan is to develop a fully-fledged rewritable drive."

Liedenbaum added that further miniaturization would be necessary before commercial products incorporating the device are possible. "We need to go from a prototype to a product, which can take some time," he said.

This will demand scaling down the optics further, and reducing the drive height to just 5 mm. The company is yet to decide whether to license the technology or to use it for Philips products only.

Author
Michael Hatcher is technology editor of Opto and Laser Europe magazine.