Abstract

Owing to progress in high density disc technology and digital video compression technology, it has become possible to playback digital videos for more than two hours with a 120 mm diameter disc. The standard for DVD (digital video disc), which had two systems in the beginning, has now been standardized to one system. The characteristics of DVD are that a red laser diode and an objective lens with a numerical aperture (NA) of 0.6 have been adopted to read high density discs, and that a 0.6 mm disc thickness has been used to secure allowance for disc tilt.

© 1996 Optical Society of America