A Phase Change Rewritable (PCR) optical disk has advantages, such as direct overwritability and high speed random access suitable for non-linear video editing, but it is necessary to increase both recording rate and capacity in order to realize high quality and long time digital video storage systems. For this purpose, this paper proposes a new Double-sided 4-head MCAV (DMCAV) method and a Mark Edge Recording (MER) technique with a 30cm diameter PCR disk.

A rewritable digital video disc recorder, using four optical heads on both sides of a 30cm disk which improves the data transfer rate up to 128Mbps for phase change rewritable media, has been developed.We achieved 19GB large capacity which realizes 20 minute Composite digital video signal recording, with new double sided multi-head MCAV method and high density mark edge recording. INTRODUCTTONA Phase Change Rewritable (PCR) optical disk has a number of advantages, among which capability of direct overwriting and elimination of the conventional need for the magnetic head are particularly attractive for video disk recorder over Magneto-Optical (MO) disk. The conventional PCR disk systems, however, lacked in both capacity and rate for long-time, high quality digital video recording.Hence, the purpose of our present study was to develop a large capacity, high transfer rate technology that permit longtime recording of high quality digital video. The new technique we have developed has the following features.At first, the recording method, unique to our development, consists of the combination of a total of four optical heads to access both sides of a disk with the Modified Constant Angular Velocity (MCAV) method. With this development both recording capacity and rate have been achieved at the same time.At second, the technique has proven that the use of both sides of a 30-cm disk achieves the recording rate of 128 Mbps and the capacity of 19 GB when combined with density improvement by the mark edge recording method. As results of these, we have realized high quality, non-compressed Composite digital video recording for 20 minutes.This paper describes the technique, focusing on the recording method and format to be used for recording on the optical disk and on signal processing procedures. O-8194-1671-1/94/$6.OO SPIE Vol. 2338 Optical Data Storage (1994) / 137 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/01/2015 Terms of Use: http://spiedl.org/terms

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We have realized a V-grooved optical disc that achieves an increase in recording density over conventional optical discs. This report describes the results of our research : namely, its fabrication process and optical read-out method.The features of the V-grooved optical disc system are:1.2mm, NA must be limited to a maximum of 0.6.