US4683176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical magnetic recording member
Assignee: Ulvac Inc
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Filing: 1984-08-15
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Granted: 1987-07-28
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Expires: 2004-08-15
Abstract
Abstract An optical magnetic recording member comprising a perpendicular-type magnetic film which is provided on a reflection film, and is made of a mixture of a ferromagnetic metal Me and a dielectric material.
Inventors
- 👤 Kyuzo Nakamura
- 👤 Yoshifumi Ota
- 👤 Tsutomu Asaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:52
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; H; H01; H01F; H01F10/00; H01F10/08; H01F10/10; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
96 words
An optical magnetic recording member comprising: (a) a composite semi-transparent perpendicular-type magnetic film made of a mixture of a ferromagnetic material and a dielectric material; (b) a reflection film formed on the perpendicular-type magnetic film; and (c) a transparent substrate for supporting said magnetic film and said reflection film, wherein the refractive index of the composite semi-transparent perpendicular-type magnetic film is larger than the refractive index of the transparent substrate, wherein the reflection film is made of a soft magnetic material or a metallic perpendicular-type magnetic film selected from the group consisting of Co--Cr and Tb--Fe.
Claim 2
Dependent Claim
96 words
An optical magnetic recording member comprising: (a) a composite semi-transparent perpendicular-type magnetic film made of a mixture of a ferromagnetic material and a dielectric material; (b) a reflection film formed on the perpendicular-type magnetic film; and (c) a transparent substrate for supporting said magnetic film and said reflection film, wherein the refractive index of the composite semi-transparent perpendicular-type magnetic film is larger than the refractive index of the transparent substrate, wherein the reflection film is made of a soft magnetic material or a metallic perpendicular-type magnetic film selected from the group consisting of Co--Cr and Tb--Fe.
Claim 3
Dependent Claim
22 words
An optical magnetic recording member as claimed in claim 1, wherein the substrate is adjacent to the composite semi-transparent perpendicular-type magnetic film.
Claim 4
Dependent Claim
51 words
An optical magnetic recording member as claimed in claim 1, wherein the ferromagnetic metal is selected from the group consisting of Fe, Co, Ni and their alloys, and the dielectric material is selected from the group consisting of oxides of Co, Fe, Ni, Al, Ti, Zr, Si, and fluorides of Mg.
Claim 5
Dependent Claim
21 words
An optical magnetic recording member as claimed in claim 1, wherein the reflection film is made of a soft magnetic material.
Claim 6
Dependent Claim
29 words
An optical magnetic recording member as claimed in claim 1, wherein the reflection film is a metallic perpendicular-type magnetic film selected from the group consisting of Co--Cr, and Tb--Fe.
Claim 7
Dependent Claim
40 words
An optical magnetic recording member as claimed in claim 1, wherein the composite semi-transparent perpendicular-type magnetic film is of such a film thickness to minimize the reflection factor of said optical magnetic recording member at any given reproducing laser wavelength.
Claim 8
Dependent Claim
29 words
An optical magnetic recording member as claimed in claim 1, wherein a transparent insulation material film is interposed between the transparent substrate and the composite semi-transparent perpendicular-type magnetic film.
Claim 9
Dependent Claim
22 words
An optical magnetic recording member as claimed in claim 7, wherein the transparent insulation material film is made of SiO 2 .
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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) | 1990-07-27 | 1991-01-26 | 1991-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-27 | 1995-01-26 | 1995-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-27 | 1999-01-26 | 1999-07-28 | $7700.00 | Window Closed / Lapsed |