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US4803660A Expired / Lapsed US ⏱️ 0.0 years remaining

Optical recording medium

Assignee: Toshiba Corp
•
Filing: 1987-02-24
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Granted: 1989-02-07
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Expires: 2007-02-24
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Abstract

Abstract In an optical memory of phase transition type such that information is recorded or erased by reversibly changing the phase of a thin recording film between equilibrium phase and non-equilibrium phase in response to a laser beam, the memory is formed with a recording film comprising as the main component an intermetallic compound with a melting point between 300 DEG to 800 DEG C. in accordance with a binary target co-sputtering technique. Since the phase transition temperature of the recording film is higher than room temperatures, the recorded film can stably be kept in non-equilibrium phase state for a long time. Further, since the melting point thereof is lower than 800 DEG C., it is possible to record or erase information in or from the medium in response to a relatively small power laser beam.

Inventors

  • 👤 Tadashi Kobayashi
  • 👤 Katsumi Suzuki
  • 👤 Naomasa Nakamura

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 15:23
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B7/266; G11B7/241; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24304; G11B2007/24308; G11B2007/24312; G11B2007/24314; G11B2007/24316; G11B7/004; G11B7/0045; G11B7/00454

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 102 words
An optical recording medium of phase transition type comprising: (a) a substrate; and (b) a recording layer supported on said substrate, said recording layer comprising more than 80% by volume of an intermetallic compound having one kind of crystalline structure in an intermediate solid phase with a melting point between 300° to 800° C. capable of undergoing phase-changing from an equilibrium phase to a non-equilibrium phase when said recording layer is heated by a laser beam and then quenched, and from a non-equilibrium phase to an equilibrium phase when said recording layer is heated by a laser beam and then cooled gradually.
Claim 2
Dependent Claim 102 words
An optical recording medium of phase transition type comprising: (a) a substrate; and (b) a recording layer supported on said substrate, said recording layer comprising more than 80% by volume of an intermetallic compound having one kind of crystalline structure in an intermediate solid phase with a melting point between 300° to 800° C. capable of undergoing phase-changing from an equilibrium phase to a non-equilibrium phase when said recording layer is heated by a laser beam and then quenched, and from a non-equilibrium phase to an equilibrium phase when said recording layer is heated by a laser beam and then cooled gradually.
Claim 3
Dependent Claim 35 words
The optical recording medium as set forth in claim 1, wherein said intermetallic compound has a normal valency compound selected from the group consisting of AuSn, AuIn 2 , InSb, BiTe, SnAs CaSb, and GeTe.
Claim 4
Dependent Claim 59 words
The optical recording medium as set forth in claim 1, wherein said intermetallic compound has a size factor compound selected from the group consisting of AuPb 2 , PdGa 5 , KPb 2 , Au 2 Pb, KBi 2 , MgZn 2 , Mg 2 Ba, Au 2 Bi, Mg 2 Sr, Mg 2 Ca, and MuSn 2 .
Claim 5
Dependent Claim 39 words
The optical recording medium as set forth in claim 1, wherein said intermetallic compound has an electron compound selected from the group consisting of MgTl 2 , LiPb, CuGa 2 , Cu 5 Cd 8 , MgHg and AuZn.
Claim 6
Dependent Claim 24 words
The optical recording medium as set forth in claim 1, wherein said recording material comprises an intermetallic compound more than 80% by volume percentage.

References Cited (Backward Citations)

US3530441A Cited
US3696344A Cited
US3971874A Cited
EP0158804A1 Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-02-07 1992-08-08 1993-02-07 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-02-07 1996-08-08 1997-02-07 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-02-07 2000-08-08 2001-02-07 $7700.00 Window Closed / Lapsed

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