Sony believes that by modifying the manufacture of CDs it can double their capacity to a maximum of 1.3GB by 2001.

The company said yesterday that it would begin licensing 'double-density' CD technology this September in conjunction with Philips Electronics. CD drives (ROM, RW, etc.) would require little or no modification to be brought in line with the higher capacity discs, the company said.

The disc manufacturing process would change to allow the track pitch to be changed to 1.6 microns, and the pit length to 0.833 microns. The optics would have to be redesigned with the lens' numerical aperture set to 0.5 for both recording and playback, but the recorded light's wavelength would stay at 780nm.

Additionally, the error correction scheme would be slightly modified, and the address format expanded, Sony said.

"Right now, the 650MB capacity [of a CD-ROM disc] is a rather tough sell compared to a standard hard drive," said Masataka Ogawa, vice-president of business planning at Sony.

The new discs are likely to be priced comparably with DVDs, and although there is no official timetable yet, the products could be available by the end of the year.®