Claims
- 1. An optical recording medium comprising in the following order:
- a substrate;
- a dielectric layer formed on the substrate;
- a reading layer formed on the dielectric layer;
- a recording layer mutually exchange-coupled to the reading layer;
- a layer made of lower thermal conductivity materials having a thermal conductivity of less than a value of 2.times.10.sup.6 erg/(s.multidot.cm.multidot.deg) and formed on the recording layer;
- a heat sink layer made of higher thermal conductivity materials having a thermal conductivity of more than a value of 5.times.10.sup.6 erg/(s.multidot.cm.multidot.deg) and formed on the layer made of lower thermal conductivity materials; and
- wherein the combined thickness of the reading and recording layers is at least 80 nm.
- 2. The optical recording medium as defined in claim 1, wherein at least one intermediate layer is interposed between said reading layer and said recording layer.
- 3. The optical recording medium as defined in claim 1, wherein said reading and recording layers are capable of detecting reading signals from a lower temperature area within an optical spot at the time of reading information.
- 4. The optical recording medium as defined in claim 1, wherein said reading and recording layers are capable of detecting reading signals from a higher temperature area within an optical spot at the time of reading information.
- 5. The optical recording medium as defined in claim 1, wherein said reading and recording layers are capable of detecting reading signals from an area between a lower temperature area and higher temperature area within an optical spot at the time of reading information.
- 6. The optical recording medium as defined in claim 1, wherein more than one of the reading and recording layers is made of an amorphous material with perpendicular magnetization comprised of a rare-earth metal and transition metal as principal components.
- 7. The optical recording medium as defined in claim 1, wherein the reading layer has a magnetic coercive force of less than 1 koe.
- 8. The optical recording medium as defined in claim 1, wherein more than one of the reading and recording layers is composed of an amorphous perpendicular magnetization layer having a thermal conductivity of less than a value of 1.times.10.sup.6 erg/(s.multidot.cm.multidot.deg).
- 9. The optical recording medium as defined in claim 1, wherein more than one of the reading and recording layers includes a nonmetallic material.
- 10. The optical recording medium as defined in claim 1, wherein said heat sink layer made of higher thermal conductivity materials is made of:
- a metal composed of a material selected from the group consisting of A1, Ag, Au, Be, Mg, Mo, W, and Rh; or
- an alloy of two or more elements selected from the group consisting of A1, Ag, Au, Be, Mg, Mo, W, and Rh; or
- an intermetallic compound composed of two or more elements selected from the group consisting of A1, Ag, Au, Be, Mg, Mo, W, and Rh.
- 11. The optical recording medium as defined in claim 1, wherein said lower thermal conductivity material is composed of a material selected from the group consisting of silicon oxide, zinc sulfide, zinc selenite, tantalum oxide, silicon nitride, aluminum nitride, 2 MgO-SiO.sub.2, and mixtures thereof.
- 12. The optical recording medium as defined in claim 1, wherein the substrate is provided with a track pitch having a value of less than 1.3 .mu.m.
- 13. An optical recording medium comprising:
- a substrate;
- a dielectric layer formed on the substrate;
- a reading layer formed on the dielectric layer;
- a switching layer formed on the reading layer;
- a recording layer formed on the switching layer;
- a lower thermal conductivity layer made of a material having a thermal conductivity of less than 2.times.10.sup.6 erg/(s.multidot.cm.multidot.deg) formed on the recording layer;
- a heat sink layer made of a material having a thermal conductivity of more than 5.times.10.sup.6 erg/(s.multidot.cm.multidot.deg) formed on the lower thermal conductivity layer; and
- wherein the combined thickness of the reading and recording layers is at least 80 nm.
- 14. An optical recording medium comprising:
- a substrate;
- a dielectric layer formed on the substrate;
- a reading layer formed on the dielectric layer;
- a read assistant layer formed on the reading layer;
- a switching layer formed on the read assistant layer;
- a recording layer formed on the switching layer;
- a lower thermal conductivity layer made of a material having a thermal conductivity of less than 2.times.10.sup.6 erg/(s.multidot.cm.multidot.deg) formed on the recording layer;
- a heat sink layer made of a material having a thermal conductivity of more than 5.times.10.sup.6 erg/(s.multidot.cm.multidot.deg) formed on the lower thermal conductivity layer; and
- wherein the combined thickness of the reading and recording layers is at least 80 nm.
Priority Claims (1)
Number |
Date |
Country |
Kind |
4-291081 |
Oct 1992 |
JPX |
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Parent Case Info
This application is a continuation of now abandoned application, Ser. No. 08/143,044, filed Oct. 29, 1993.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4310899 |
Bresterbus et al. |
Jan 1982 |
|
4628485 |
Tanaka et al. |
Dec 1986 |
|
4814238 |
Tanaka et al. |
Mar 1989 |
|
Foreign Referenced Citations (4)
Number |
Date |
Country |
258978 |
Mar 1988 |
EPX |
60-7633 |
Jan 1985 |
JPX |
3-054741 |
Mar 1991 |
JPX |
3-105738 |
May 1991 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
143044 |
Oct 1993 |
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