US4637953A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetooptical recording medium with laminated anti-reflection film
Assignee: Canon Inc
•
Filing: 1984-05-29
•
Granted: 1987-01-20
•
Expires: 2004-05-29
Abstract
Abstract A magnetooptical recording medium is provided which comprises (a) a light-transmissive substrate formed of a material selected from the group consisting of plastic and glass, (b) a multilayer film disposed on said light-transmissive substrate, and multilayer film being formed by alternate lamination in three or more odd number of a high-refractive film composed of a high-refractive material and a low-refractive film containing SiO 2 as the main constituent and the film in contact with said light-transmissive substrate being a high refractive film, and (c) a recording magnetic layer disposed on said multilayer film, recording on said magnetic film being performed by a light beam transmitting said substrate and said multilayer.
Inventors
- 👤 Mitsuharu Sawamura
- 👤 Susumo Ito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:08
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10593; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/261
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
155 words
A magnetooptical recording medium comprising: (a) a light transmissive substrate formed of a material selected from the group consisting of plastic and glass; (b) a multilayer film disposed on said light-transmissive substrate, said multilayer film having an odd number of layers of at least 3 in number and being formed by alternate lamination of a high-refractive film which is a binary vapor-deposited film comprising a mixture of Ta 2 O 5 and ZrO 2 , and a low-refractive film containing SiO 2 as the main constitutent and the film in contact with said light-tramissive substrate being a high refractive film, wherein each of the layers of said multilayer film has an optical thickness of λ/4, where λ is a wave length of recording and readout light; and (c) a recording magnetic layer disposed on said multilayer film wherein recording on said magnetic film is performed by a light beam traversing said substrate and said multilayer.
Claim 2
Dependent Claim
155 words
A magnetooptical recording medium comprising: (a) a light transmissive substrate formed of a material selected from the group consisting of plastic and glass; (b) a multilayer film disposed on said light-transmissive substrate, said multilayer film having an odd number of layers of at least 3 in number and being formed by alternate lamination of a high-refractive film which is a binary vapor-deposited film comprising a mixture of Ta 2 O 5 and ZrO 2 , and a low-refractive film containing SiO 2 as the main constitutent and the film in contact with said light-tramissive substrate being a high refractive film, wherein each of the layers of said multilayer film has an optical thickness of λ/4, where λ is a wave length of recording and readout light; and (c) a recording magnetic layer disposed on said multilayer film wherein recording on said magnetic film is performed by a light beam traversing said substrate and said multilayer.
Claim 3
Dependent Claim
22 words
The magnetooptical recording medium according to claim 1, in which said magnetic recording layer is a quaternary amorphous thin film comprising Gd-Tb-Fe-Co.
Claim 4
Dependent Claim
154 words
A magnetooptical recording medium comprising: (a) a light transmissive substrate formed of a material selected from the group consisting of plastic and glass; (b) a multilayer film disposed on said light-transmissive substrate, said multilayer film having an odd number of layers of at least 3 in number and being formed by alternate lamination of a high-refractive film which is a binary vapor-deposited film comprising a mixture of Nb 2 O 5 and ZrO 2 , and a low-refractive film contaiing SiO 2 as the main constituent and film in contact with said light-transmissive substrate being a high refractive film, wherein each of the layers of said multilayer film has an optical thickness of λ/4, where λ is a wave length of recording and readoug light; and (c) a recording magnetic layer disposed on said multilayer film wherein recording on said magnetic film is performed by a light beam traversing said substrate and said multilayer.
Claim 5
Dependent Claim
154 words
A magnetooptical recording medium comprising: (a) a light transmissive substrate formed of a material selected from the group consisting of plastic and glass; (b) a multilayer film disposed on said light-transmissive substrate, said multilayer film having an odd number of layers of at least 3 in number and being formed by alternate lamination of a high-refractive film which is a binary vapor-deposited film comprising a mixture of Nb 2 O 5 and ZrO 2 , and a low-refractive film contaiing SiO 2 as the main constituent and film in contact with said light-transmissive substrate being a high refractive film, wherein each of the layers of said multilayer film has an optical thickness of λ/4, where λ is a wave length of recording and readoug light; and (c) a recording magnetic layer disposed on said multilayer film wherein recording on said magnetic film is performed by a light beam traversing said substrate and said multilayer.
Claim 6
Dependent Claim
22 words
The magnetooptical recording medium according to claim 3 in which said magnetic recording layer is a quaternary amorphous thin film comprising Gd-Tb-Fe-Co.
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) | 1990-01-19 | 1990-07-21 | 1991-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-19 | 1994-07-21 | 1995-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-19 | 1998-07-21 | 1999-01-20 | $7700.00 | Window Closed / Lapsed |