Patent EP0158804A1 successfully refreshed from Google Patents.
EP0158804A1
Expired / Lapsed
EP
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Apparatus for information recording and reproducing
Assignee: Hitachi Ltd
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Filing: 1985-03-06
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Granted: —
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Expires: 2005-03-06
Abstract
Abstract The invention concerns to a method and an apparatus for recording and reproducing information, which are carried out by using a recording medium made of a metal or alloy having phases different in their crystalline structures at at least two temperature regions in the solid state and capable of causing phase transformation by heating and quenching. Information such as signals, letters, patterns and symbols are recorded in a distinctive manner and erased by making use of a change in the spectral reflectance owing to the phase transformation. Rewriting can be made easily by making use of the nergy of a light beam such as a laser beam.
Inventors
- 👤 Tetsuro Minemura
- 👤 Hisashi Ando
- 👤 Isao Ikuta
- 👤 Yoshiaki Kita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 15:23
CPC Classifications
G; G11; G11B; G11B7/00; G11B9/00; G11B9/10; G11B7/004; G11B7/0055; G11B7/00557; G11B7/24; G11B7/241; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24308
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
45 words
An information recording and reproducing apparatus characterized by comprising a recording medium which has at least two kinds of crystalline structures in the solid state and which can maintain one of said crystalline structures obtained in one temperature region even in the other temperature region.
Claim 2
Dependent Claim
45 words
An information recording and reproducing apparatus characterized by comprising a recording medium which has at least two kinds of crystalline structures in the solid state and which can maintain one of said crystalline structures obtained in one temperature region even in the other temperature region.
Claim 3
Dependent Claim
49 words
An information recording and reproducing apparatus as claimed in claim 1, wherein said recording medium is made of a metal or alloy which is capable of maintaining a crystalline structure at a high temperature region even in a low temperature region by being super-cooled from said high temperature region.
Claim 4
Dependent Claim
105 words
An information recording and reproducing apparatus as claimed in claim 1, wherein said recording medium is made of a crystalline metal or alloy capable of causing a phase transformation, said metal or alloy having at least two phases of different crystalline structures at different temperature regions in solid state, said apparatus further comprising a heating means and a reproducing means capable of recording and erasing informations such as signals, letters, patterns and symbols by making use of a change in the spectral reflectance owing to the transformation from one phase to another phase which in turn is caused by the operation of said heating means.
Claim 5
Dependent Claim
99 words
An information recording and reproducing apparatus as claimed in claim 2, wherein said recording medium is made of a metal or alloy which can have a low-temperature crystalline structure obtained in a low-temperature region and a high-temperature crystalline structure obtained in a high-temperature region, said high-temperature crystalline being formed by heating said recording medium at least partially to said high-temperature region and capable of being maintained even in said low-temperature region when said metal or alloy is quenched, said high-temperature crystalline structure and said low-temperature crystalline structure exhibiting different spectral reflectances thereby allowing recording, erasion and reproduction of information.
Claim 6
Dependent Claim
86 words
An information recording and reproducing apparatus as claimed in claim 2, wherein said recording medium is made of a metal or alloy which maintains the high-temperature crystalline structure in the low-temperature region, said high-temperature crystalline structure being transformable at least partially into the low-temperature crystalline structure when said metal or alloy is heated to a temperature higher than the temperature maintaining said high-temperature crystalline structure followed by a cooling, said transformation causing a change in the spectral reflectance thus allowing recording, erasion and reproduction of information.
Claim 7
Dependent Claim
42 words
An information recording and reproducing apparatus as claimed in claim 1, wherein said recording medium is a metal or alloy mainly composed of metals selected from elements belonging to groups Ib to VIIb and VIII of the periodic table or transition metals.
Claim 8
Dependent Claim
79 words
An information recording and reproducing apparatus according to claim 6, wherein said recording medium is made of a Cu-base alloy containing at least one of Al, Ga, In, Sb, Si, Sn and Zn, said Cu-base alloy having a high-temperature crystalline structure including S-phase formed and maintained in a low-temperature region as a result of heating followed by a quenching, and a low-temperature crystalline structure including a-phase, said high-temperature crystalline structure and said low-temperature crystalline structure exhibiting different spectral reflectances.
Claim 9
Dependent Claim
28 words
An information recording and reproducing apparatus as claimed in claim 7, wherein the martensitic transformation temperature of S-phase in said recording medium is lower than the room temperature.
Claim 10
Dependent Claim
38 words
An information recording and reproducing apparatus as claimed in claim 7, wherein said recording medium is made of a material containing at least one of transition metals, B, C, Bi, Ge, Ag, Cd, Au, Pb, Be and Mg.
Claim 11
Dependent Claim
29 words
An information recording and reproducing apparatus as claimed in claim 1, wherein said recording medium is a foil or film formed by quench-solidification directly from gaseous or liquid phase.
Claim 12
Dependent Claim
23 words
An information recording and reproducing apparatus as claimed in claim 1, wherein said recording medium is a thin film formed on a substrate.
Claim 13
Dependent Claim
37 words
An information recording and reproducing apparatus as claimed in claim 1, wherein said recording medium is a powder which is applied to the surface of a substrate so as to form a thin film on said substrate.
Claim 14
Dependent Claim
29 words
An information recording and reproducing apparatus as claimed in claim 1, wherein said recording medium is divided into fine segments of a size corresponding to the unit of recording.
Claim 15
Dependent Claim
41 words
An information recording and reproducing apparatus as claimed in claim 1, wherein either one of the heating means for recording and the heating means for erasion is a laser beam or electron beam, while the reproducing means is a laser beam.
Claim 16
Dependent Claim
63 words
An optical disc comprising a thin film of recording medium formed on a tracking groove in a substrate, said thin film being made of a metal or alloy which has at least two kinds of crystalline structures in the solid state, said metal or alloy being capable of holding the crystalline structure formed in one temperature region even in the other temperature region.
Claim 17
Dependent Claim
63 words
An optical disc comprising a thin film of recording medium formed on a tracking groove in a substrate, said thin film being made of a metal or alloy which has at least two kinds of crystalline structures in the solid state, said metal or alloy being capable of holding the crystalline structure formed in one temperature region even in the other temperature region.
Claim 18
Dependent Claim
26 words
An optical disc according to claim 15, wherein said recording medium is protected by a coating film of material which causes no chemical change by heating.
Claim 19
Independent Claim
158 words
A method of recording, reproducing and erasing information having the steps of: preparing a recording medium made of a material which has at least two kinds of crystalline structures in the solid state and which is capable of maintaining the crystalline structure obtained in one temperature region even in the other temperature region; locally heating the recording medium to form the high-temperature crystalline structure followed by a super-cooling so as to maintain the thus formed crystalline structure even after being cooled to the lower-temperature region thus recording the desired information; applying a light beam to the recorded portion of the recording medium so as to detect any difference in the optical characteristics between said locally heated portion and a portion which was not heated, thus reproducing the recorded information; and heating the recorded portion of the recording medium to a temperature which is lower than the temperature of said local heating for recording, thus erasing the recorded information.
Claim 20
Independent Claim
158 words
A method of recording, reproducing and erasing information having the steps of: preparing a recording medium made of a material which has at least two kinds of crystalline structures in the solid state and which is capable of maintaining the crystalline structure obtained in one temperature region even in the other temperature region; locally heating the recording medium to form the high-temperature crystalline structure followed by a super-cooling so as to maintain the thus formed crystalline structure even after being cooled to the lower-temperature region thus recording the desired information; applying a light beam to the recorded portion of the recording medium so as to detect any difference in the optical characteristics between said locally heated portion and a portion which was not heated, thus reproducing the recorded information; and heating the recorded portion of the recording medium to a temperature which is lower than the temperature of said local heating for recording, thus erasing the recorded information.
Claim 21
Dependent Claim
33 words
A memory material having at least two kinds of crystalline structures in the solid state and capable of maintaining the crystalline structure obtained in one temperature region even in the other temperature region.
Claim 22
Dependent Claim
33 words
A memory material having at least two kinds of crystalline structures in the solid state and capable of maintaining the crystalline structure obtained in one temperature region even in the other temperature region.
References Cited (Backward Citations)
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