phase-change recording

phase-change recording

[¦fāz ‚chānj ri′kȯrd·iŋ]
(computer science)
An optical recording technique that uses a laser to alter the crystalline structure of a metallic surface to create bits that reflect or absorb light when they are illuminated during the read operation.
References in periodicals archive ?
In November Sony announced ultra-density optical (UDO): a phase-change recording scheme for storing at least 40GB (20GB/side) on 5.25-inch media.
The advanced phase-change recording layer technologies also yield superior archival life and produce discs that are ideal for storing images, presentations, Internet downloads, and audio files.
In phase-change recording, the recording/erasure processes involve crystalline-amorphous atomic structural changes (atoms move around); therefore these processes are slower and more prone to wear-out phenomena.
In phase-change recording technology, a laser beam heats a thin-film material that can be in one of two states: (1) amorphous, in which there is very low reflectance, or (2) crystalline, in which there is very high reflectance.
And the phase-change recording layer is specified to sustain--for up to 1,000 rewrite cycles--the same ratio of amorphous-to-crystalline reflectivity (i.e., 18- to 30 percent) as that of replicated DVD-ROMs.
In developing the new high-capacity DVD-RAM discs, Maxell utilized optical thermal simulation to optimize the crystallization and diffusion speed of the phase-change recording layer.
In addition, Mark Edge Recording was employed in the phase-change recording layer production to increase the pit density to 0.3 micrometers and the track density to 0.60 micrometers.