US5087340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making magneto-optical recording disk
Assignee: Pioneer Corp
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Filing: 1990-10-10
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Granted: 1992-02-11
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Expires: 2010-10-10
Abstract
Abstract A magneto-optical recording disk comprises a transparent substrate on which a magneto-optical recording layer made of a rare earth-transition metal alloy having an uniaxial magnetic anisotropy is sandwiched by a pair of dielectric layers is characterized that the dielectric layers are deposited in an amorphous state by means of a low pressure sputtering method.
Inventors
- 👤 Nobuaki Onagi
- 👤 Shinichiro Suzuki
- 👤 Seiro Fujii
- 👤 Takahiro Kobayashi
- 👤 Takamasa Yoshikawa
- 👤 Masayasu Yamaguchi
- 👤 Kiyohide Ogasawara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:42
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
187 words
A method of manufacturing a magneto-optical recording disk comprising a magneto-optical recording layer made of an amorphous rare earth-transition metal alloy having a uniaxial magnetic anisotropy in the normal direction of said layer, said magneto-optical recording layer disposed between at least one pair of dielectric layers made of zinc sulfide and formed over a transparent substrate, which comprises the steps of: introducing said transparent substrate into an airtight vacuum chamber of a thin film forming apparatus for conducting a sputtering method so that said substrate is positioned in a substantially vacuum atmosphere; sputter depositing zinc sulfide onto said substrate under an Argon pressure of 0.2 through 1.0 mTorr, whereby a first zinc sulfide layer is produced in an amorphous state; sputter depositing a rare earth-transition metal amorphous alloy onto said first zinc sulfide layer, whereby a magneto-optical recording layer is produced; sputter depositing zinc sulfide onto said magneto-optical recording layer under an Argon pressure of 0.2 through 1.0 mTorr, whereby a second zinc sulfide layer is produced in an amorphous state, and wherein the manufactured magneto-optical recording disk has a high C/N ratio greater than 65 dB.
Claim 2
Independent Claim
187 words
A method of manufacturing a magneto-optical recording disk comprising a magneto-optical recording layer made of an amorphous rare earth-transition metal alloy having a uniaxial magnetic anisotropy in the normal direction of said layer, said magneto-optical recording layer disposed between at least one pair of dielectric layers made of zinc sulfide and formed over a transparent substrate, which comprises the steps of: introducing said transparent substrate into an airtight vacuum chamber of a thin film forming apparatus for conducting a sputtering method so that said substrate is positioned in a substantially vacuum atmosphere; sputter depositing zinc sulfide onto said substrate under an Argon pressure of 0.2 through 1.0 mTorr, whereby a first zinc sulfide layer is produced in an amorphous state; sputter depositing a rare earth-transition metal amorphous alloy onto said first zinc sulfide layer, whereby a magneto-optical recording layer is produced; sputter depositing zinc sulfide onto said magneto-optical recording layer under an Argon pressure of 0.2 through 1.0 mTorr, whereby a second zinc sulfide layer is produced in an amorphous state, and wherein the manufactured magneto-optical recording disk has a high C/N ratio greater than 65 dB.
Claim 3
Dependent Claim
15 words
A method recording disk according to claim 1 wherein said Argon pressure is 0.3 mTorr.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-02-10 | 1995-08-12 | 1996-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-10 | 1999-08-12 | 2000-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-10 | 2003-08-12 | 2004-02-11 | $7700.00 | Window Closed / Lapsed |