Toshiki Aoi

Optical Phase Change Disc without Bulk Laser Initialization and a Quick Bulk Initialization Structure

Optical phase change discs without bulk laser initialization were produced. When an Sb film was partially separated by more than 7 nm from a V added Ag–In–Sb–Te alloy film, the as-deposited reflectivity of the disc was almost the same as that of a disc with an initial alloy film after annealing by bulk laser erasing. Further, the recording and overwriting properties of the discs without bulk laser erasing were estimated. The recording jitter of the 1–7 frequency modulation signal increased during the first 2 or 3 overwriting iterations and then saturated at less than 3.5 ns until 30,000 overwriting iterations at a linear constant velocity of 12 m/s. Additionally, the disc could be initialized at the overwriting speed.

Reversible Read-Write-Erase Properties of Styrene Oligomer Optical Recording Media

Optical recording media consisting of a thermoplastic oligomer resin blended with a photoabsorbing pigment permit heat-mode pit writing without corona discharge, as well as heat erasure and rewriting. The properties of recording layers consisting of styrene oligomers having number-average molecular weights (Mn) of 400 or 3000 blended with copper phthalocyanine or anthraquinone pigment, when subjected to recording and playback operations with a helium-neon (He–Ne) laser, are investigated. In addition, full-surface heat erasure, and scanning heat erasure are discussed. Pits with an outside diameter of 2.5 µm were recorded (writing time, 2 µsec) with a 10 mW He–Ne laser light. A readout signal contrast (ratio of reflected light intensity in the absence of pits to that in the presence of pits) of 3 was obtained.