Abstract

The newly agreed high-density read-only format, DVD, adopts two 0.6 mm disks attached back to back as a standard, in order to allow the optical system to have more tilt angle margin, with high numerical aperture (NA) objective lens. On the other hand, the conventional CD family disks are 1.2 mm thick, single side. Since diffraction-limited spot quality is essential to read the preformed pit signals with sufficient accuracy, spherical aberration caused by the disk plate must be corrected appropriately. We have proposed the new optical head with aperture-control capability using liquid crystal shutter (LCS), which can play both CDs and DVDs with single objective lens which is corrected for only DVD disk thickness.

© 1996 Optical Society of America