EP0186911A2
Expired / Lapsed
EP
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Reversible memory system
Assignee: Toshiba Corp
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Filing: 1985-12-27
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Granted: —
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Expires: 2005-12-27
Abstract
Abstract in a reversible memory system, a pulsed laser beam generated from a laser unit is directed to a recording layer (2) formed on a substrate 1. The recording layer (2) essentially consists of a recording medium, for example, an iron-nickel alloy containing iron as a mayor component and 27 to 30 atomic % of nickel, which undergoes martensite transformation from a low-temperature phase (D) to a high-temperature phase (E) at a predetermined temperature Af and which undergoes a stress-induced transformation (a 2 ) at a characteristic temperature Md. When a region of the recording layer is irradiated with the laser beam having a predetermined intensity, the region undergoes a stress-induced transformation (a 2 ) so that the region is changed from the high temperature phase (A) to the low temperature phase (8).
Inventors
- 👤 Sumio C/O Patent Division Ikegawa
- 👤 Yoshiaki C/O Patent Division Terashima
- 👤 Nobuaki C/O Patent Division Yasuda
- 👤 Katsutarou C/O Patent Division Ichihara
- 👤 Shuichi C/O Patent Division Komatsu
- 👤 Shinji C/O Patent Division Arai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 17:32
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/0045; G11B7/00454; G11B11/00; G11B11/10; G11B11/105; G11B11/16; G11B11/18; G11B11/20; G11B5/00; G11B7/24; G11B7/241; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24306; G11B2007/24308; G11B2007/2431
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
177 words
l. A reversible memory system characterized by comprising: a substrate (1, 21) having a given surface; a recording layer (2, 22) formed on the given surface of said substrate (1, 21) and consisting of a recording medium (2, 22) which undergoes martensitic transformation from a first to a second phase at a predetermined temperature or upon application of pressure, and which undergoes a stress-induced transformation (a 2 ) in a region in which a pressure is applied at a temperature equal to a characteristic temperature Md or less, the region in which the pressure is applied undergoing a transformation from the first to the second phase; means (13) for generating a pulsed laser beam; means (14, 15) for directing the laser beam toward said recording layer in a recording mode, so as to allow the region in said recording layer (2, 22) irradiated with the laser beam to undergo a stress-induced transformation (a 2 ); and detecting means (16, 17) for detecting whether a region in said recording layer (2) is in the first or second phase.
Claim 2
Dependent Claim
29 words
A system according to claim 1, characterized in that said recording medium (2, 22) is converted from the second phase to the first phase by a martensitic reverse transformation.
Claim 3
Dependent Claim
36 words
A system according to claim 1, characterized in that the overall recording medium (2, 22) is gradually heated and is thereafter gradually cooled so as to be converted from the second phase to the first phase.
Claim 4
Dependent Claim
51 words
A system according to claim 1, characterized in that a portion of said recording medium (2, 22) is irradiated with a laser beam and is locally and gradually heated and is then gradually cooled so that said recording medium (2, 22) is converted from the second phase to the first phase.
Claim 5
Dependent Claim
41 words
A system according to claim 1, characterized in that said recording medium (2, 22) essentially consists of an iron-nickel alloy containing iron as a major component, 27 to 34% by weight of nickel, and 0 to 2% by weight of carbon.
Claim 6
Dependent Claim
34 words
A system according to claim 1, characterized in that said recording medium (2, 22) essentially consists of an iron-nickel alloy containing iron as a major component and 27 to 30 atomic % of nickel.
Claim 7
Dependent Claim
41 words
A system according to claim 1, characterized in that said recording medium (2, 22) essentially consists of a copper-aluminum alloy containing copper as a major component, 9 to 15% by weight of aluminum, and 0 to 5% by weight of nickel.
Claim 8
Dependent Claim
24 words
A system according to claim 1, characterized in that said recording medium (2, 22) has different colors in the first and the second phases.
Claim 9
Dependent Claim
48 words
A system according to claim 1, characterized by further comprising a transparent dielectric layer (23, 23-1, 23-2) formed on a substrate (1, 21) together with said recording layer (2, 22), the laser beam being radiated to said recording layer (2, 22) through said dielectric layer (23, 23-1, 23-2).
Claim 10
Dependent Claim
56 words
A system according to claim 9, characterized in that said recording medium (2, 22) essentially consists of a copper-aluminum alloy containing copper as a major component and 9 to 15% by weight of aluminum, and said transparent dielectric film (23, 23-1, 23-2) essentially consists of silicon nitride and has a thickness of 40 to 140 nm.
Claim 11
Dependent Claim
43 words
A system according to claim 9, characterized in that said recording medium (2, 22) essentially consists of a copper-aluminum alloy contaning copper as a main component and 9 to 15% by weight of aluminum and has a thickness of 15 to 40 nm.
Claim 12
Dependent Claim
78 words
A system according to claim 1, characterized by further comprising a reflection film (24) for reflecting light formed on opposite side of a light incident surface of said recording layer (2, 22) and said transparent dielectric film (23, 23-1, 23-2), said recording layer (2, 22) transmits the laser beam, the transmitted laser beam is reflected by said reflection film (24), and the laser beam reflected by said reflection film (24) becomes incident on said recording layer (2, 22).
Claim 13
Dependent Claim
55 words
A system according to claim 12, characterized in that said recording medium (2, 22) essentially consists of a copper-aluminum alloy containing copper as a major component and 9 to 15% by weight of aluminum, and said transparent dielectric film (23, 23-1, 23-2) consists of silicon nitride and has a thickness of 40 to 140 nm.
Claim 14
Dependent Claim
43 words
A system according to claim 12, characterized in that said recording medium (2, 22) essentially consists of a copper-aluminum alloy containing copper as a major component and 9 to 15% by weight of aluminum and has a thickness of 15 to 40 nm.
References Cited (Backward Citations)
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