US5058099A
Expired / Lapsed
US
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Magneto-optical memory element
Assignee: Sharp Corp
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Filing: 1989-08-09
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Granted: 1991-10-15
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Expires: 2009-08-09
Abstract
Abstract A magneto-optical memory element has a multi-layer construction in the order from a side first receiving light from a light-source which includes a first transparent dielectric film, a rare earth transition metal alloy film, a second transparent dielectric film and a reflective film. The magneto-optical device uses circular dichroism effect of a magnetic mater for reading information. The rare earth transition metal alloy film has a refractive index represented by n±Δn wherein n=3.2-3.55i and Δn=0.05-0.03i. The thickness of film is about 18 to 46 nm. The second transparent dielectric film has a refractive index of 2.0±0.2 and a film thickness of 80 to 108 nm.
Inventors
- 👤 Yoshiteru Murakami
- 👤 Akira Takahashi
- 👤 Kazuo Van
- 👤 Junichiro Nakayama
- 👤 Hiroyuki Katayama
- 👤 Kouji Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:03
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/06; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10584; G11B11/10586
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
117 words
A magneto-optical memory element having a multi-layer construction and a magnetic material to produce a circular dichroism effect, comprising: a first transparent dielectric film; a rare earth transition metal alloy film positioned on said first transparent dielectric film; a second transparent dielectric film positioned on said rare earth transition metal alloy film; and a reflective film positioned on said second transparent dielectric film; said rare earth transition metal alloy film having a refractive index represented by n±Δn wherein n=3.2-3.55i and Δn=0.05-0.03i; said rare earth transition metal alloy film having a film thickness of 18 to 46 nm; said second transparent dielectric film having a refractive index of 2.0±0.2 and a film thickness of 80 to 108 nm.
Claim 2
Dependent Claim
117 words
A magneto-optical memory element having a multi-layer construction and a magnetic material to produce a circular dichroism effect, comprising: a first transparent dielectric film; a rare earth transition metal alloy film positioned on said first transparent dielectric film; a second transparent dielectric film positioned on said rare earth transition metal alloy film; and a reflective film positioned on said second transparent dielectric film; said rare earth transition metal alloy film having a refractive index represented by n±Δn wherein n=3.2-3.55i and Δn=0.05-0.03i; said rare earth transition metal alloy film having a film thickness of 18 to 46 nm; said second transparent dielectric film having a refractive index of 2.0±0.2 and a film thickness of 80 to 108 nm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-14 | 1995-04-15 | 1995-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-14 | 1999-04-15 | 1999-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-14 | 2003-04-15 | 2003-10-15 | $7700.00 | Window Closed / Lapsed |