Mitsubishi Chemical Corporation

Mitsubishi Kagaku Media Co., Ltd.

Pioneer Corporation

Michikazu Horie

Takashi Ohno

Masae Kubo

Natsuko Nobukuni

Masaaki Mizuno

Haruo Kunitomo

Hiroyuki Hoshino

Hironobu Mizuno

Hideyuki Kubo

Kenjirou Kiyono

Yutaka Kurose

Akio Okamuro

Ken-Ichi Takada

Yuki Suzuki

Yuko Okamoto

Kanako Tsuboya

Eiji Muramatsu

Hiroshi Nishiwaki

Shuuichi Maeda

Masao Komatsu

Syuichi Maeda

Kenichi Takada

Ken' Ichi Takada

Ken'Ichi Takada

Kenjiro Kiyono

An optical recording method for recording mark length-modulated information on a recording medium by using a plurality of recording mark lengths. The optical recording method comprises the steps of:

Optical recording method and optical recording medium

An information recording medium () is provided with (i) a first information recording area wherein a first track for reproducing first information based on a first track pitch is formed by a laser beam, and (ii) a second information recording area wherein a second track for reproducing second information based on a second track pitch different from the first track pitch is formed by a laser beam. The groove shape of the first track is different from the groove shape of the second track.

Information recording medium, information reproducing device and method, and apparatus and method for manufacturing information recording medium

Provided is an extremely high-density optical recording medium with excellent jitter characteristics and good recording/reproducing characteristics. An optical recording mediumcomprises a substratewith a guide groove formed therein, a layerwith a light reflection function, a recording layercomprising a dye as a main component with a light absorption function for a wavelength of recording/reproducing light in an unrecorded state, and a cover layercapable of transmitting the recording/reproducing light incident to the recording layer, in the order mentioned; an interlayercontaining at least one element selected from the group consisting of Ta, Nb, V, W, Mo, Cr and Ti, is provided between the layerwith the light reflection function and the recording layer

Optical recording medium

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

By use of a substrate which can be stably formed and has a relatively small groove depth, a very high density optical recording medium having good recording/reading characteristics is provided. In an optical recording medium of a surface incidence type, in which a reflective layer, a recording layer containing a dye as a main component and a cover layer are sequentially formed on a substrate having guide grooves formed therein, a guide groove part on a far side from a plane of incidence of a recording/reading light beam on the cover layer is set as a recording groove part, and reflected light intensity in a recorded pit portion formed in the recording groove part is increased by a phase shift and is set higher than reflected light intensity in unrecorded.

Optical recording medium and optical recording method of the same

For an optical recording medium having a phase change type recording layer on its a substrate and having as read only area and a writable area in a recording area, a data recording method is provided which records data in the writable area. This data recording method comprises a transfer step of transferring program data recorded in the read only area in a practical form to an external computer, and an execution step (step A) of automatically executing the program data in the external computer to record data in the writable area, which can facilitate manufacturing and reduce the possible of destruction or falsification of ROM data.

Data erase method for rewritable phase change type recording medium

A phase-change recording material used for an information recording medium utilizing a crystalline state as a non-recorded state and an amorphous state as a recorded state, which has the composition of the following formula (1) as the main component:(SbSn)GeTeM1&#x2003;&#x2003;formula (1)wherein each of x, y, z and w represents atomicity, x, z and w are numbers which satisfy 0.01&#x2266;x&#x2266;0.5, 0&#x2266;z&#x2266;0.3 and 0&#x2266;w&#x2266;0.1, respectively, and the element M1 is at least one element selected from the group consisting of In, Ga, Pt, Pd, Ag, rare earth elements, Se, N, O, C, Zn, Si, Al, Bi, Ta, W, Nb and V, and

Phase-change recording material used for information recording medium and information recording medium employing it

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.

In a rewritable compact disc having a wobble groove on a substrate, crystal and amorphous states of a phase-change recording layer are an unrecorded/erased state and a recorded state, respectively. When the recording layer is exposed to recording light, amorphous marks assuming the recorded state are formed. At any of 2-, 4- and 8-times velocities with respect to a reference velocity (1-times velocity) whose linear velocity is 1.2-1.4 m/s, modulation mof a recorded signal when the recording light of approximately 780 nm in wavelength irradiates the recording layer via an optical system with NA=0.5 or 0.55 is 60-80%. A topmost level Rof reflectivity of the eye pattern of the recorded signal during retrieving at the 1-times velocity is 15-25%, and a jitter of the individual length of marks and inter-mark spaces during retrieving at 1-times velocity is 35 ns or less. Recording at 8-times or higher velocities is thereby realized without any risk of impairing the read-compatibility with the conventional CD-RW specifications at least at 4-times velocity.

Rewritable optical recording medium, recording method on the same, and optical disc recording/retrieving apparatus

An optical information recording medium for recording information by a plurality of record mark lengths, wherein the shortest mark length is at most 0.5 &#x3bc;m, and a crystal state is an unrecorded or erased state and an amorphous state is a recorded state, wherein the erasing is carried out by recrystallization which substantially proceeds by crystal growth from an interface between the amorphous portion or a melt portion and a peripheral crystal portion; and an optical recording method suitable therefore. The medium of the present invention has characteristics that overwriting can be made at a high speed, the jitter of mark edge is small, mark length modulation recording can be made at a high density, and the formed mark is excellent in the stability with the lapse of time.

Optical information recording medium and optical recording method

In an optical recording method used when information is recorded in a phase-change recording layer of a large-capacity rewritable optical recording medium such as a DVD-RW, one block pulse is used as a recording pulse for forming one recording mark when a recording velocity is higher than a recording linear velocity at which the rewritable optical recording medium can be rewritten, whereas a pulse train comprised of a plurality of short pulses is used as the recording pulse for forming one recording pulse when the recording velocity is within recording linear velocities at which the rewritable optical recording medium can be rewritten, whereby high-velocity recording is realized.

Phase-change recording layer optical recording method

In a rewritable compact disc having a wobble groove on a substrate, crystal and amorphous states of a phase-change recording layer are an unrecorded/erased state and a recorded state, respectively. When the recording layer is exposed to recording light, amorphous marks assuming the recorded state are formed. At any of 2-, 4- and 8-times velocities with respect to a reference velocity (1-times velocity) whose linear velocity is 1.2&#x2013;1.4 m/s, modulation mof a recorded signal when the recording light of approximately 780 nm in wavelength irradiates the recording layer via an optical system with NA=0.5 or 0.55 is 60&#x2013;80%. A topmost level Rof reflectivity of the eye pattern of the recorded signal during retrieving at the 1-times velocity is 15&#x2013;25%, and a jitter of the individual length of marks and inter-mark spaces during retrieving at 1-times velocity is 35 ns or less. Recording at 8-times or higher velocities is thereby realized without any risk of impairing the read-compatibility with the conventional CD-RW specifications at least at 4-times velocity.

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Kanagawa, Japan

Michikazu Horie