Michio Miura

Highly reliable 7-GB, 1.2- to 2.2-MB/s, 12-inch write-once optical disk

In order to extend an application area of 12 inch write once optical disks, both a larger data capacity and higher data transfer rate are required, which in turn requires more advanced reliability and durability. This paper describers a double sided 7GB twelve inch diameter disk suitable for high data transfer (1.2-2.2 MB/s) application. A storage data capacity is increased by using both the pit- edge method and the Modified Constant Angular Velocity (MCAV) method. The corrosion resistant Te based ternary alloy recording layer has an excellent pit length characteristics and less thermal interference, which results in wide jitter margin in the pit edge detection. The high speed disk rotation gives the high data transfer rate. Acceleration tests prove a disk life longer than 45 years.

Optical Head Using Astigmatic Micro PBS For 3.5 Inch Magneto-Optical Disk Drives

It is required that a drive for a 3.5 inch (90 mm) magneto-optical (MO) disk should be the same size as that of a floppy disk so that it can be installed into the host computers drive slot instead of the floppy disk drive. We realized a compact-size optical head for the 3.5 inch disk drives by developing an astigmatic micro PBS (polarized beam splitter) as an analyzer. The astigmatic micro PBS (ASPBS) has both a polarizing function for the MO detection and an astigmatic function for the focus detection. And our optical head is based on the discrete block servo format (DBF).