EP0239974A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Magneto-optical recording medium
Assignee: NEC Home Electronics Ltd
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Filing: 1987-03-30
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Granted: —
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Expires: 2007-03-30
Abstract
Abstract The magneto-optical recording medium structure comprises a transparent substrate (l0), a primary protective layer (ll) formed on the transparent substrate (l0), a magneto-optical recording layer (l2) made from material having the magneto-optical effect formed on the primary protective layer (ll), and a protective layer (l3) formed on the recording layer (l2). The primary protective layer (ll) and the protective layer (l3) are formed from Y₂O₃ (yttrium oxide) and/or a higher or lower Y₂O₃ oxide.
Inventors
- 👤 Katsuda Shinichi
- 👤 Matsumoto Takayuki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 01:34
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
75 words
A magneto-optical recording medium for recording information comprising: a transparent substrate (l0); first protecting means (ll) for protecting said transparent substrate (l0); means (l2) for recording information; second protecting means (l3) for protecting said recording means (l2), wherein said recording means (l2) is provided between said first (ll) and second protecting means (l3), and said first (ll) and second protecting means (l3) are made from one of Y₂O₃ and/or a higher or lower Y₂O₃ oxide.
Claim 2
Dependent Claim
75 words
A magneto-optical recording medium for recording information comprising: a transparent substrate (l0); first protecting means (ll) for protecting said transparent substrate (l0); means (l2) for recording information; second protecting means (l3) for protecting said recording means (l2), wherein said recording means (l2) is provided between said first (ll) and second protecting means (l3), and said first (ll) and second protecting means (l3) are made from one of Y₂O₃ and/or a higher or lower Y₂O₃ oxide.
Claim 3
Dependent Claim
26 words
A magneto-optical recording medium as claimed in claim l, wherein refractive indexes of said first (ll) and second protecting means (l3) are set at over l.8.
Claim 4
Dependent Claim
22 words
A magneto-optical recording medium as claimed in claim 2, wherein said refractive indexes are set within the range of l.86 ∼ l.95.
Claim 5
Dependent Claim
33 words
A magneto-optical recording medium as claimed in one of the preceding claims, wherein the crystal structure of Y₂O₃ and/or a higher or lower Y₂O₃ oxide is of a rare earth oxide C type.
Claim 6
Dependent Claim
30 words
A magneto-optical recording medium as claimed in claim 4, wherein a ratio of the crystal face (440) in the crystal structure is higher than that of the crystal face (332).
Claim 7
Dependent Claim
29 words
A magneto-optical recording medium as claimed in claim 5, wherein the ratio of the crystal face (440) is over l/30 time higher than that of the crystal face (222).
Claim 8
Dependent Claim
35 words
A magneto-optical recording medium as claimed in claim l, wherein the thickness of said first protecting means (ll) is adjusted to λ/4 or approximately odd times the wavelength λ/4 of a laser beam for use.
Claim 9
Dependent Claim
19 words
A magneto-optical recording medium of one of the preceding claims, wherein the substrate (l0) is made from PC (polycarbonate).
References Cited (Backward Citations)
No citation records indexed.
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