Michiaki Shinotsuka

Structural Analysis of Ag–In–Sb–Te Phase-Change Material

The Ag–In–Sb–Te system is widely used for phase-change discs such as compact disc rewritable (CD-RW) and rewritable digital versatile disc (DVD+RW). To clarify the effect of Ag and In in the Ag–In–Sb–Te system, we studied the local structure of Ag–In–Sb–Te phase-change material by extended X-ray absorption fine structure (EXAFS). The results suggest that the existence of Ag contributes to the thermal stability of amorphous marks and existence of In contributes to high-speed phase-change.

High-Density and High-Data-Transfer-Rate Optical Disk with Blue Laser Diode and Ag-In-Sb-Te Phase-Change Material

We studied phase-change recording using a 405 nm blue laser diode, an objective lens of numerical aperture (NA)=0.6 and Ag–In–Sb–Te phase-change material. We report land and groove recording on a conventional disk structure with a 0.6-mm-thick and 120-mm-diameter PC substrate. We confirmed the possibility of achieving a high density, 12 GB capacity and a high data-transfer rate of 30 Mbps, corresponding to that of a read-only digital versatile disk (DVD-ROM) under the conditions of 6.5 m/s recording speed, 0.18 µm/bit linear density (minimum mark length 0.27 µm) and 0.42 µm trackpitch.

Potentiality of the Ag-In-Sb-Te phase change recording material for high density erasable optical discs

The feasibility of using Ag-In-Sb-Te phase change material for high density of directly overwritable optical discs has been studied. A linear density of 0.34 μm /bit with a track pitch of 0.74 μm is confirmed to be achievable with a light source wavelength of 680 nm, with an objective lens NA of 0.60 and the criteria of data-to-data jitter of less than 14% of the channel bit length. The recording characteristics are also studied using an optical system with a 635 nm red laser diode in order to investigate the attainment of a linear density of 0.267 μm/bit which is equivalent to the DVD-ROM (read only memory) specification.

Semi transparent Recording Stack with Fast-Crystallization Phase-Change Material for Dual-Layer Optical Disk

We report the experimental results of a semi transparent recording stack with a fast-crystallization (FC) phase-change material for a dual-layer optical disk, using a pickup with a blue laser diode at 405 nm and a lens numerical aperture (NA) of 0.85 to achieve the highest capacity. The transmittance of 47% and the clock-to-data jitter of approximately 9% were obtained from the semi transparent recording stack. We confirmed that the FC phase-change material could be applied to a high-capacity dual-layer recording system.

High-speed blue-laser recording on the double-decker phase change disk with high-reliability

In this paper, we report the feasibility of 100 Mbps data transfer-rate with high reliability and wide-power margin that media can apply to double-deck high density recording of 42 GB capacity corresponding to an optical recording disk system (K. Schep et al, ISOM Tech. Dig., p. 210, 2000) using a blue laser diode at 405 nm, and NA (numerical aperture) of 0.85.

100-Mbps high-speed phase-change recording with blue laser

We have studied a phase-change recording with a blue laser diode wavelength (405nm), an objective lens (NA 0.85) and Ag-In-Sb-Te system phase change material. We report land and groove recording on a 0.1mm thin cover disk structure, and 120mm-diameter polycarbonate substrate. Finally we confirmed the possibility of high data transfer-rate 100Mbps and high-density 20.9GB corresponding to those of a new optical recording system (DVR) (1) at the condition of recording velocity 17m/s, linear density of 0.130 micrometers /bit and 0.35 micrometers track-pitch.