Victor Company of Japan, Limited

Kenji Tokui

Hiroshi Tabata

Ikuo Matsumoto

Kenichi Shimomai

Kazuo Yonehara

Yoshiteru Matsubayashi

Shinji Higuchi

Masashi Yoshikawa

Yuji Ohata

Jyunji Oshita

Data is recorded in a phase-change optical storage medium having data layers. A first recording pulse sequence is generated for recording to a first data layer located most remote from a beam-incident surface. The first sequence has a recording pulse carrying an erasing power and a recording power rising from the erasing power, and a cooling pulse carrying a bottom power lower than the erasing power. A second recording pulse sequence is generated for recording to a second data layer. The second sequence has recording pulse carrying an erasing power and a recording power rising from the erasing power, a cooling puse carrying a bottom power lower than the erasing power, and an erasing top pulse carrying an erasing top power higher than the erasing power.

Optical recording method, optical recording apparatus and optical storage medium

A phase-change optical storage medium has a substrate and a recording layer having a plurality of tracks for storing information. A material of which the recording layer is made has been initialized in a crystalline state in which an amplitude of a tracking-detection signal is smaller than a saturation value of the amplitude, the tracking-detection signal being obtained by receiving a reflected beam from the recording layer when the recording layer is irradiated with a laser beam in an off-track state while the optical storage medium is being rotated.

Phase-change optical recording medium having tracking signal smaller than saturation value

A phase-change optical storage medium has a substrate, and a recording layer, to be recorded on which is at least one recorded mark representing information to be recorded by irradiating a recording light beam onto the recording layer in accordance with a recording pulse pattern of recording pulses rising from an erasing power and formed between a recording power larger than the erasing power and a bottom power smaller than the erasing power and of erasing pulses rising from the bottom power to the erasing power. The expressions (1) and (2): 1.00&#x3c;(R/R)&#x3c;1.15 . . . (1), 1.05&#x3c;(R/R)&#x3c;1.20 . . . (2) are satisfied for the recording layer, in which Ris a reflectivity exhibited by an un-recorded section of the recording layer, on which no data has ever been recorded, when irradiated with a reproducing light beam, Ris a reflectivity exhibited by the un-recorded section when irradiated with the reproducing light beam, after irradiated once with the recording light beam in accordance with the recording pulse pattern, and Ris a reflectivity exhibited by the un-recorded section when irradiated with the reproducing light beam, after irradiated nine times with the recording light beam in accordance with the recording pulse pattern.

Phase-change recording medium having the relation between pulse patterns and reflectivity of un-recorded section

Information to be recorded is recorded in a recording layer of a phase-change optical storage medium. The information to be recorded is modulated to generate modulated data. Desired mark-length data is generated based on the modulated data. Generated further based on the mark-length data is a recording pulse pattern of recording pulses rising from an erasing power and formed between a recording power larger than the erasing power and a bottom power smaller than the erasing power and of erasing pulses rising from the bottom power to the erasing power. A recording light beam is then irradiated onto the recording layer in accordance with the recording pulse pattern to record at least one recorded mark representing the information to be recorded. Used in recording is an optimum erasing power, as the erasing power, the optimum erasing power satisfying an expression (1): 1.000&#x3c;(R/R)&#x3c;1.030 . . . (1) in which Ris a reflectivity exhibited by an un-recorded section of the recording layer, on which no data has ever been recorded, when irradiated with a reproducing light beam, and Ris a reflectivity exhibited by the un-recorded section when irradiated with the reproducing light beam after irradiated once with a beam having the erasing power.

An optical disk consists of a first laminated layer structure and a second laminated layer structure. The first structure has a first transparent substrate having a first surface and a second surface on both sides thereof, provided on the first surface being a light-incident plane via which a light beam is to be incident in recording or reproduction, formed alternately on the second surface being a plurality of first lands and first grooves, and a first organic-dye recording layer formed on the second surface to cover the first lands and grooves. The second structure has a second substrate, alternately formed on which are a plurality of second lands and second grooves, a reflective film formed on the second transparent substrate to cover the second lands and grooves, and a second organic-dye recording layer formed on the reflective film to face the second transparent substrate. The first and the second structures are bonded to each other via a bonding layer so that the first and second recording layers are provided between the first and second substrates. A formula &#x3b1;&#x2267;cos(20/Tb) is satisfied in which Tb is a thickness of the reflective film formed on a bottom of each second groove and &#x3b1;is an angle between a plane passing through an upper surface of each second land and a side wall of each second groove.

Optical storage medium

The present invention provides a thin magnetic tape for allowing a long play without degrading electro-magnetic transfer characteristics and mechanical strength of the magnetic tape. The magnetic tape comprises a base film, an an under layer provided on the base film, and a magnetic layer containing magnetic particles coated on the under layer. The under layer contains magnetic plate-particles each having a configuration such that a ratio of a major axis to a minor axis observed in a plate-like surface is preferred to be approximately 1 and a ratio of the major axis to a thickness off the magnetic particles is to be 5.about.10 so that the under layer has Young's modulus of not less than 2.0.times.10.sup.10 N/m.sup.2 in a longitudinal direction of the magnetic tape and has virtually the same value in a traversing direction thereof. The magnetic plate-particles have an easy axis of magnetization in a longitudinal direction of the magnetic tape to improve the electro-magnetic transfer characteristics and mechanical strength thereof by forming magnetic flux coupling between the magnetic plate-particles in the under layer and the magnetic particles in the magnetic layer.

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Hitachinaka, Japan

Kenji Tokui