Hitachi Maxell, Limited

Akira Kashiwakura

Makoto Iimura

Makoto Miyamoto

Katsusuke Shimazaki

Masafumi Yoshihiro

Reiji Tamura

Naoki Kitagaki

Hiroshi Shirai

Yoshihiro Ikari

Kazuyoshi Adachi

Hisanori Sugiyama

Mayumi Kurokawa

Sonoko Onodera

Kazuyo Umezawa

Yutaka Watanabe

Shin-Itsu Kinoshita

Norio Oota

A phase-change optical recording medium capable of performing recording and reproduction at a high speed is provided, in which a reproduced signal output is not only sufficiently large but the phase-change optical recording medium also has excellent repeated rewriting performance. An interface layer, which is composed of a Ge&#x2014;Si&#x2014;N-based material, is formed on at least a surface of one side of a recording layerof the phase-change optical recording medium. Accordingly, even when a phase-change material having a high melting point, for example, a Bi&#x2014;Ge&#x2014;Te-based phase-change material is used for the recording layer, it is possible to provide the phase-change optical recording medium in which the reproduced signal output is sufficiently large and the repeated rewriting performance is excellent.

Phase-change optical recording medium

A write-once optical information recording medium is provided that is capable of realizing a high transfer rate and a method of recording and reproducing information on and from the optical information recording medium. The optical information recording medium is constructed by stacking a reflective layer, a first dielectric layer, a recording layer, a write-protect layer, a second dielectric layerand a transparent cover layeron a polycarbonate substrate. The recording layeris made of a phase-change material, and the cover layeris made of UV curing resin. The recording layeris irradiated with a laser beam with a wavelength of 500 nm or less to change from a crystalline phase to an amorphous phase. The write-protect layerprevents the recording layerfrom changing back to the crystalline phase from the amorphous phase, formed by the phase change.

Optical information recording medium and method of recording and reproducing information on and from optical information recording medium

A magnetooptic recording medium which includes a substrate and a magnetooptic recording film thereon, the substrate having a surface comparted into a plurality of tracks on which magnetooptic recording signals are recorded, and a part of the tracks, selected from the plurality of tracks, including clusters of pre-pits wherein a variation of a change in light amount due to local birefringence in the vicinity of the pre-pits is not more than 20% with respect to a change in light amount in the absence of the local birefringence, when signals from the tracks with recorded magnetooptic recording signals are measured by changes in light amount on the basis of Kerr rotational angles of reflected light from the medium, which magnetooptic recording medium can be effectively used for a ZCAV system.

Magnetooptic recording medium

Growing community of inventors

Moriya, Japan

Akira Kashiwakura