Paper
1 July 1991 Erasable compact disk utilizing phase-change material and multipulse recording method
Eiji Ohno, Kenichi Nishiuchi, Noboru Yamada, Nobuo Akahira
Author Affiliations +
Proceedings Volume 1499, Optical Data Storage '91; (1991) https://doi.org/10.1117/12.45926
Event: Optical Data Storage, 1991, Colorado Springs, CO, United States
Abstract
A feasibility of phase change media to an erasable compact disk (CD) was studied. We proposed a quadrilayered optical disk having a recording layer of Ge12Sb39Te49 thin film. The ternary material film was crystallized and also amorphized reversibly by laser irradiation of 0.7 microsecond(s) . This transition time was appropriate for the CD which revolves at 1.2-1.4 m/s. A multi-pulse (MP) recording method was also proposed to record EFM signals without teardrop shaped distortions. On the revolving disk, each recording mark of amorphous state was formed by irradiation of 'multi-pulses': a set of one preceding longer pulse and succeeding shorter pulses. Newly developed simple electric circuit for producing the MP waveform was examined to overwrite the single frequency signals of 196 kHz and 720 kHz, alternatively using only one laser beam. As a result, carrier to noise ratio (CNR) of more than 50 dB, secondary harmonic distortion (SHD) of -40 dB, and erasability of 40 dB were obtained. It was observed by a transmission electron microscope that the teardrop shaped distortion of the recording mark was reduced. Eight to fourteen modulation (EFM) signals of the audio CD format were also overwritten successfully and a clear eye-pattern was confirmed. The combination of the GeSbTe phase change media and the MP recording method will be applicable to the erasable compact disk.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Eiji Ohno, Kenichi Nishiuchi, Noboru Yamada, and Nobuo Akahira "Erasable compact disk utilizing phase-change material and multipulse recording method", Proc. SPIE 1499, Optical Data Storage '91, (1 July 1991); https://doi.org/10.1117/12.45926
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Cited by 6 scholarly publications and 1 patent.
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KEYWORDS
Compact discs

Crystals

Antimony

Laser crystals

Optical storage

Germanium antimony tellurium

Laser irradiation

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