



Current optical disc systems are speed-capped at about 10,000 rpm (revolutions per minute.) Spin them any faster and there's a danger the discs will physically disintegrate in the drive leaving nothing but a pile of sharp plastic splinters and data that is gone forever -- and even if they don't break apart the disc can begin to wobble making reliable recording a problem, notes IDG.
Engineers at the Science and Technical Research Laboratories (STRL) of Japan's public broadcaster, NHK (Nippon Hoso Kyokai), are working on an optical disc recording system based on consumer Blu-ray Disc technology that can spin as fast as 15,000 rpm without these problems.
NHK has gotten around the stress problem by making a flexible disc that's only 0.1 millimeters thick. The disc, co-developed with Ricoh., is essentially the recording layer from a Blu-ray Disc without the 1.1 millimeter plastic substrate used to give the disc rigidity. It won't break apart at higher speeds but isn't rigid enough to be useful in a drive at any speed, says IDG. To solve this second problem a thick stabilizing plate has been added into the drive. When spun, the disc is kept steady by the stabilizer and can be used up to 15,000 rpm, said Daiichi Koide, an engineer at NHK STRL.
The new technology is needed because broadcast quality HDTV signals of the type NHK records stream at 250M bps (bits per second) making a fast-spinning optical disc a necessity, says IDG. A 1X Blu-ray Disc records at 36M bps so the new system is equivalent to 7X speed.



