Mitsubishi Kagaku Media Co., Ltd.

Mitsubishi Chemical Corporation

Akio Okamuro

Takashi Ohno

Michikazu Horie

Hiroyuki Hoshino

Masae Kubo

Masaaki Mizuno

Kenjirou Kiyono

Toshifumi Kawano

Jun Kanehira

A rewritable optical recording medium including: a substrate having a guide groove formed thereon, a phase-change type recording layer, a portion in a crystalline state of the phase-change type recording layer corresponds to an unrecorded or erased state, and a portion in an amorphous state of the phase-change type recording layer corresponds to a recorded state, so that an amorphous mark corresponding to the recorded state is formed upon irradiation with a recording laser beam. The phase-change type recording layer contains Sb as a main component, and further contains Ge and/or Te, a content of Ge is from 1 atomic % to 30 atomic %, and a content of Te is from 10 atomic % to 30 atomic %, and in the phase-change type recording layer, Sb/Te is at least 4.5, and the atomic ratio of Ge to Te is from 1:3 to 1:20.

Rewritable optical recording medium and optical recording method

A rewritable optical recording medium includes a substrate and a phase-change type recording layer. A portion in a crystalline state corresponds to an unrecorded or erased state, and a portion in an amorphous state correspond to a recorded state, to record EFM modulated information by forming amorphous marks by irradiating the recording layer with a recording laser beam, and the recording is carried out by irradiating a recording laser beam having a wavelength of about 780 nm through an optical system having a numerical aperture NA of 0.5 or 0.55, at 24-times velocity or 32-times velocity of the reference velocity.

The present invention provides CD-RW which makes high velocity recording at a level of at least 24-times velocity possible, rewritable DVD which makes high velocity recording at a level of at least 6-times velocity possible, and a recording method therefor, while maintaining interchangeability with conventional CD-RW standards and rewritable DVD standards. A rewritable optical recording medium comprising a substrate and a phase-change type recording layer, wherein a portion in a crystalline state corresponds to an unrecorded or erased state, and a portion in an amorphous state correspond to a recorded state, to record EFM modulated information by forming amorphous marks by irradiating the recording layer with a recording laser beam, and wherein recording is carried out by irradiating a recording laser beam having a wavelength of about 780 nm through an optical system having a numerical aperture NA of 0.5 or 0.55, at 24-times velocity or 32-times velocity of the reference velocity, where the reference velocity (1-time velocity) is a linear velocity of from 1.2 m/s to 1.4 m/s, modulation mof record signals is from 60% to 80%, the top value Rof the reflectivity of the high pattern is from 15% to 25%, and jitters are at most 35 nsec.

An optical recording medium simultaneously having higher recording characteristics and storage stability than ever, is obtained. An optical recording medium comprising at least a phase change recording layer, a first diffusion preventing layer, a second diffusion preventing layer and a protective layer formed in this order on a substrate, characterized in that the first diffusion preventing layer and the second diffusion preventing layer comprise a non-gas element and nitrogen and/or oxygen as the main components, the non-gas element in each of the first diffusion preventing layer and the second diffusion preventing layer, is the same, and the content (atomic %) of nitrogen and/or oxygen contained in the second diffusion preventing layer, is larger than the content (atomic %) of nitrogen and/or oxygen contained in the first diffusion preventing layer.

Optical recording medium

A magneto-optical recording medium having a writing layer, a switching layer and a readout layer on a substrate, wherein a magnetization direction corresponding to information is written in the writing layer, and the magnetization direction of the writing layer is transferred to the readout layer by a magnet static coupling force from the writing layer at a temperature of at least room temperature, and wherein the writing layer is composed of a plurality of layers which are made of alloys of a rare earth metal and a transition metal and which are exchange-coupled one another, including a layer having rare earth metal dominant magnetization at room temperature and a layer having transition metal dominant magnetization at room temperature.

Growing community of inventors

Tokyo, Japan

Akio Okamuro