Kazuoki Hongu

New Inorganic Write-Once Disc Using Low-Cost and Environmentally Friendly Oxynitride Materials for Multilayer Disc System

We have developed a new inorganic write-once disc using low-cost and environmentally friendly recording materials of Si oxynitride and Al oxynitride with high transmittance. Data-to-clock jitters of 5.6% for Layer 1, 5.5% for Layer 2, and 6.3% for Layer 3 of the individual single-layer discs were obtained using a limit equalizer. This newly developed recording material is immensely promising for a multilayer disc system.

A New Inorganic Write-Once Disc using Hydrogen-Containing Dielectric Recording Material for Multi-Layered Blu-ray Disc System

We have developed a completely novel inorganic write-once disc using a hydrogen-containing dielectric recording material. We demonstrate the recording characteristics of a newly developed write-once disc on the basis of the Blu-ray disc format (dual-layered, 4? speed).

A DWDD disc of 27-Gbit/in2 land-groove recording using a blue laser and side-wall-annealing technique

We realized acceptable read/write performances at a track pitch of 320 nm and a bit length of 75 nm, even with an NA of 0.65 and a wavelength of 405 nm, using side-wall-annealing. In addition to this result, we suggested the possibility of a higher linear density; that is, a jitter value of less than 15% was obtained both on land and in groove at a bit length of 60 nm, which corresponds to an areal density of 34 Gbit/in2.

System tolerance of 64-mm-diameter magneto-optical disks with a 4.7-Gigabyte capacity

We observed sufficiently wide detection tolerances in a magneto-optical (MO) drive system based on the domain-wall-displacement detection (DWDD) method. Those DWDD disks had a capacity of 4.7 Giga-byte on 64 mm diameter substrates optimized for land and groove (L/G) recording. Addressing was performed with the assistance of a one-side-wobbled groove. We investigated two types of DWDD disks i.e. the anneal-less type and the sidewall-annealed type.