Ricoh Company, Ltd.

Wedg Co., Ltd.

Yukio Ide

Makoto Harigaya

Hiroko Iwasaki

Yoshiyuki Kageyama

Katsuyuki Yamada

Hiroshi Deguchi

Yujiro Kaneko

Masaetsu Takahashi

Yoshitaka Hayashi

Michiaki Shinotsuka

Narihito Kojima

Itaru Fujimura

Kohichi Ohshima

Yuki Nakamura

Michiharu Abe

Hiroshi Nagame

Eiji Noda

Kenichi Aihara

Fumiya Ohmi

Kyohji Hattori

Takashi Rokutanzono

Michihisa Takahashi

Masako Kunita

Osamu Nonoyama

Naoki Yoshida

Tadafumi Tatewaki

Teruyuki Ohnuma

Hideo Sakurai

Shinji Nousho

Seiichi Ohseto

Kouichi Ohshima

Michiaki Shinozuka

Shinji Nosho

Shoji Nitta

Yoshiyuki Kageyma

An information recording and erasing apparatus configured to record information on and erase other information from a thermo-sensitive recording medium which medium is capable of heat-reversible coloring and discoloring, the information recording and erasing apparatus includes an erasing unit configured to move the thermo-sensitive recording medium from one side to another side, heat the thermo-sensitive recording medium, and erase the other information recorded in the thermo-sensitive recording medium; and a recording unit provided in a direction perpendicular to a moving direction of the thermo-sensitive recording medium with the erasing unit, the recording unit being configured to record the information in the thermo-sensitive recording medium where the other information is erased by the erasing unit.

Information recording and erasing apparatus

A sputtering target contains a target material including as constituent elements Ag, In, Te and Sb with the respective atomic percents (atom. %) of &#x3b1;, &#x3b2;, &#x3b3; and &#x3b4; thereof being in the relationship of 0.5&#x2266;&#x3b1;&#x3c;8, 5&#x2266;&#x3b3;&#x2266;23, 17&#x2266;&#x3b3;&#x2266;38, 32&#x2266;&#x3b4;&#x2266;73, &#x3b1;&#x2266;&#x3b3;, and &#x3b1;+&#x3b2;+&#x3b3;+&#x3b4;=100, and a method of producing the above sputtering target is provided.

Method of producing a sputtering target

A method of initializing a phase-change optical information recording medium is provided, using an optical system incorporating a semiconductor laser device. The laser device is characterized by a specified spatial power distribution. In a spatial distribution of the laser power focused on the recording medium, in the direction perpendicular to guide tracks the laser device preferably has less average smaller in both end regions of the spatial distribution, which have each 10% of the width at half maximum of the distribution, than the average in the center region of the full width at half maximum of the distribution.

Initialization of phase-change optical recording medium

A sputtering target contains a target material including as constituent elements Ag, In, Te and Sb with the respective atomic percents (atom. %) of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 0.5&lE;&agr;<8, 5&lE;&bgr;&lE;23, 17&lE;&ggr;&lE;38, 32&lE;&dgr;&lE;73, &agr;&lE;&bgr;, and &agr;&plus;&bgr;&plus;&ggr;&plus;&dgr;&equals;100, and a method of producing the above sputtering target is provided. An optical recording medium includes a recording layer containing a phase-change recording material which includes as constituent elements Ag, In, Te and Sb with the respective atomic percents of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 1&lE;&agr;<6, 7&lE;&bgr;&lE;20, 20&lE;&ggr;&lE;35, 35&lE;&dgr;&lE;70, and &agr;&plus;&bgr;&plus;&ggr;&plus;&dgr;&equals;100, and is capable of recording and erasing information by utilizing the phase change of the recording material in the recording layer. A method of forming the above recording layer for the optical recording medium is also provided. In addition, there is provided an optical recording method using the above-mentioned phase-change optical recording medium.

A sputtering target for fabricating a recording layer of a phase-change type optical recording medium contains a compound or mixture including as constituent. elements Ag, In, Te and Ob with the respective atomic percent (atom. %) of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 2&lE;&agr;&lE;30, 3&lE;&bgr;&lE;30, 10&lE;&ggr;&lE;50, 15&lE;&dgr;&lE;83 and &agr;&plus;&bgr;&plus;&ggr;&plus;&dgr;&equals;100, and a method of producing the above sputtering target is provided. A phase-change type optical recording medium includes a recording layer containing as constituent elements Ag, In, To and Sb with the respective atomic percent of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 0<&agr;&lE;30, 0<&bgr;&lE;30, 10&lE;&ggr;&lE;50, 10&lE;&dgr;&lE;80, and &agr;&plus;&bgr;&plus;&ggr;&plus;&dgr;&equals;100, and is capable of recording and erasing information by utilizing the phase changes of a recording material in the recording layer. A method of fabricating the above phase-change type optical recording medium is also provided.

Sputtering target, method of producing the target, optical recording medium fabricated by using the sputtering target, and method of fabricating the optical recording medium

Sputtering target, method of producing the target, optical recording medium fabricated by using the sputtering target, and method of forming recording layer for the optical recording medium

A sputtering target for fabricating a recording layer of a phase-change type optical recording medium contains a compound or mixture including as constituent elements Ag, In, Te and Sb with the respective atomic percent (atom. %) of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 2&lE;&agr;&lE;30, 3&lE;&bgr;&lE;30, 10&lE;&ggr;&lE;50, 15&lE;&dgr;&lE;83 and &agr;&plus;&bgr;&plus;&ggr;&plus;&dgr;&equals;100, and a method of producing the above sputtering target is provided. A phase-change type optical recording medium includes a recording layer containing as constituent elements Ag, In, Te and Sb with the respective atomic percent of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 0<&agr;&lE;30, 0<&bgr;&lE;30, 10&lE;&ggr;&lE;50, 10&lE;&dgr;&lE;80, and &agr;&plus;&bgr;&plus;&ggr;&plus;&dgr;&equals;100, and is capable of recording and erasing information by utilizing the phase changes of a recording material in the recording layer. A method of fabricating the above phase-change type optical recording medium is also provided.

A sputtering target for fabricating a recording layer of a phase-change type optical recording medium contains a compound or mixture including as constituent elemets Ag, In, Te and Sb with the respective atomic percent (atom. %) of .alpha., .beta., .gamma. and .delta. thereof being in the relationship of 2.ltoreq..alpha..ltoreq.30, 3.ltoreq..beta..ltoreq.30, 10.ltoreq..gamma..ltoreq.50, 15.ltoreq..delta..ltoreq.83 and .alpha.+.beta.+.gamma.+.delta.=100, and a method of producing the above sputtering target is provided. A phase-change type optical recording medium includes a recording layer containing as constituent elements Ag, In, Te and Sb with the respective atomic percent of .alpha., .beta., .gamma. and .delta. thereof being in the relationship of 0&lt;.alpha..ltoreq.30, 0&lt;.beta..ltoreq.30, 10.ltoreq..gamma..ltoreq.50, 10.ltoreq..delta..ltoreq.80, and .alpha.+.beta.+.gamma.+.delta.=100, and is capable of recording and erasing information by utilizing the phase changes of a recording material in the recording layer. A method of fabricating the above phase-change type optical recording medium is also provided.

Sputtering target, method of producing the target, optical recording

An optical information recording medium capable of recording information, reproducing recorded information, erasing recorded information, and rewriting recorded information, is composed of a substrate, a recording layer formed on the substrate, the recording layer including as the main component a four-component phase-change recording material comprising Ag, In, Te and Sb, and containing a crystalline phase composed of the microcrystallites of AgSbTe.sub.2 at the erasure of recorded information, an upper heat resistant protective layer formed on the recording layer, the upper heat resistant protective layer including a heat resistant material with a thermal conductivity of 1.0 W/cm.deg or more, and an optical reflecting layer formed on the upper heat resistant protective layer. Optical information can be recorded in this recording medium by applying a laser beam to the recording layer through the substrate at a linear velocity of disc rotation of 1.2 to 5.6 m/sec.

Optical information recording medium and recording method by use of the

A sputtering target, for forming a recording layer of an optical recording medium in which information is written and erased through a transition between two phases by utilizing electromagnetic wave energy, consists of a heat-treated and sintered composition represented by the formula:

Heat treated and sintered sputtering target

A sputtering target for fabricating a recording layer of a phase-change type optical recording medium contains a compound or mixture including as constituent elements Ag, In, Te and Sb with the respective atomic percent (atom.%) of .alpha., .beta., .gamma.and .delta.thereof being in the relationship of 2.ltoreq..alpha..ltoreq.30, 3.ltoreq..beta..ltoreq.30, 10.ltoreq..gamma..ltoreq.50, 15.ltoreq..delta..ltoreq.83 and .alpha.+.beta.+.gamma.+.delta.=100, and a method of producing the above sputtering target is provided. A phase-change type optical recording medium includes a recording layer containing as constituent elements Ag, In, Te and Sb with the respective atomic percent of .alpha., .beta., .gamma.and .delta.thereof being in the relationship of 0&lt;.alpha..ltoreq.30, 0&lt;.beta..ltoreq.30, 10.ltoreq..gamma..ltoreq.50, 10.ltoreq..delta..ltoreq.80, and .alpha.+.beta.+.gamma.+.delta.=100, and is capable of recording and erasing information by utilizing the phase changes of a recording material in the recording layer. A method of fabricating the above phase-change type optical recording medium is also provided.

Sputtering target for producing optical recording medium

When recording data according to the PWM recording system by modulating signals, pulse modulation for pulse modulation for recording for recording a 0 signal or the like having a signal width of nT (T: Clock time) after modulation is a continuous electro-magnetic wave at a power level e, a record signal pulse array for recording a 1 signal or the like having a signal width of nT after modulation comprises a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which a low level pulse at a power level b and a high power pulse at a power level c having a time width T in total alternately appear (n-n') times in all with a duty ratio y, and a pulse section op having a time width z and a power level d, and x, y, z are integers satisfying the conditions of 0.5 T.ltoreq.x.ltoreq.2 T, 0.4.ltoreq.y.ltoreq.0.6 and 0.5 T.ltoreq.z.ltoreq.1 T, and n' is a positive integer which is equal to or smaller than n, and controls are provided so that the condition of (a and c)&gt;e &gt;(b and d) is satisfied.

Phase-change optical recording method using pulse width modulation

When recording data according to the PWM recording system by modulating signals, pulse modulation for pulse modulation for recording for recording a 0 signal or the like having a signal width of nT (T: Clock time) after modulation is a continuous electro-magnetic wave at a power level e, a record signal pulse array for recording a 1 signal or the like having a signal width of nT after modulation comprises a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which a low level pulse at a power level b and a high power pulse at a power level c having a time width T in total alternately appear (n-n') times in all with a duty ratio y, and a pulse section op having a time width z and a power level d, and x, y, z are integers satisfying the conditions of 0.5T .ltoreq.x.ltoreq.2T, 0.4.ltoreq.y.ltoreq.0.6 and 0.5T.ltoreq.z.ltoreq.1T, and n' is a positive integer which is equal to or smaller than n, and controls are provided so that the condition of (a and c)&gt;e&gt;(b and d) is satisfied.

Phase-change type optical recording and reproducing method

A sputtering target contains a target material including as constituent elements Ag, In, Te and Sb with the respective atomic percents (atom. %) of .alpha., .beta., .gamma. and .delta. thereof being in the relationship of 0.5.ltoreq..alpha.&lt;8, 5.ltoreq..beta..ltoreq.23, 17.ltoreq..gamma..ltoreq.38, 32.ltoreq..delta..ltoreq.73, .alpha..ltoreq..beta., and .alpha.+.beta.+.gamma.+.delta.=100, and a method of producing the above sputtering target is provided. An optical recording medium includes a recording layer containing a phase-change recording material which includes as constituent elements Ag, In, Te and Sb with the respective atomic percents of .alpha., .beta., .gamma. and .delta. thereof being in the relationship of 1.ltoreq..alpha.&lt;6, 7.ltoreq..beta..ltoreq.20, 20.ltoreq..gamma..ltoreq.35, 35.ltoreq..delta..ltoreq.70, and .alpha.+.beta.+.gamma.+.delta.=100, and is capable of recording and erasing information by utilizing the phase change of the recording material in the recording layer. A method of forming the above recording layer for the optical recording medium is also provided. In addition, there is provided an optical recording method using the above-mentioned phase-change optical recording medium.

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Mishima, Japan

Yukio Ide