Nine of the world's largest electronics companies have joined forces to help commercialize a next-generation optical disk system called Blu-ray disk.

They plan to release a specification for the blue-laser-based system within months. The format is aimed initially at recording high-definition TV video, but the system offers more data storage (27GB) than available on existing DVD formats (4.7GB).

Because blue lasers have a shorter wavelength than the red lasers employed in CD players and existing DVD players, the laser beams can be focused on smaller areas of the disk surface. This means each bit of data can be stored on a smaller surface area, increasing disk capacity.

The Blu-ray disk group includes six of the ten companies that worked to develop the DVD format: Hitachi, Panasonic, Philips, Pioneer, Sony and Thomson Multimedia. Also involved are Sharp, LG Electronics and Samsung.

The group expects disks to be available in three similar sizes: 23.3GB, 25GB and 27GB. These sizes reflect the different aims of the companies involved.

A notable absentee from the group is Toshiba, which currently chairs the DVD Forum, the industry body that promotes and extends existing DVD standards.