Abstract

Recently a high density optical disk system: DVD (having about 7 times higher recording capacity than that of the conventional CD disk) has been announced to be marketed within this year. The DVD has designed to have a sufficient capacity enough to store full length movies, and is also expected to be used as a large capacity memory for the personal computer memory application. This DVD disk has a same diameter to that of the CD disk, but its substrate thickness is halved to realize the high recording density, the DVD disks are made by bonding two 0.6 mm thickness substrates back to back and we can read data from each/single side. As a DVD being a kind of optical disks, the DVD drive is assumed to have a compatibility to be able to read conventional CD disks besides DVDs, though the used optical parameters are definitely different We studied several compatible pickup head designs, and we successfully realized a truly compatible optical pickup head which overcame 2 times different substrate thickness and different recording density. We report the structure of our DVD/CD compatible pickup.

© 1996 Optical Society of America