1. High-Density Recording Capability of Five-Layered Phase-Change Optical Disc
- Author
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Hiroshi Hasegawa, Hiromichi Kobori, Maho Kuwahara, Naoki Morishita, Naomasa Nakamura, Katsutaro Ichihara, Katsumi Suzuki, and Keiichiro Yusu
- Subjects
Materials science ,Laser diode ,business.industry ,General Engineering ,General Physics and Astronomy ,Numerical aperture ,law.invention ,Lens (optics) ,Constant linear velocity ,Wavelength ,Optics ,law ,Optical recording ,business ,Optical disc ,Jitter - Abstract
High-density recording capability of the five-layered phase-change disc has been examined from the viewpoints of optical simulation and disc performance. The optical simulation showed that the temperature rise in the amorphous state balanced that in the crystal state for the case when the thickness of the lower protective layer was adjusted from 70 nm to 120 nm. Carrier-to-noise ratio (CNR), overwriting erase ratio and jitter were measured by the optical recording system using a laser diode with a wavelength of 636 nm and an objective lens of 0.6 numerical aperture. Track-pitch was fixed at 0.6 µm and bit length was varied at a linear velocity of 6 m/s. CNR of 52 dB, overwriting erase ratio of more than 35 dB, and overwriting jitter of less than 10% were obtained on both land and groove at a bit length of 0.34 µm/bit.
- Published
- 1998
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