Patent US4639816A successfully refreshed from Google Patents.
US4639816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magneto-optical recording medium
Assignee: Canon Inc
•
Filing: 1983-09-26
•
Granted: 1987-01-27
•
Expires: 2003-09-26
Abstract
Abstract This specification discloses a magneto-optical recording medium, comprising a substrate; a magnetic film formed on the substrate and having an axis of easy magnetization perpendicular to the film surface; and an arrangement for establishing a reflection factor of not more than 10% at the surface of the magnetic film.
Inventors
- 👤 Yasuo Tomita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:54
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10591; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
105 words
A magneto-optical recording medium which is adapted for use in a reading system in which a linearly polarized light beam is projected on said medium whereby a light beam reflected by said medium is detected by a photoconductor, said photoconductor having a multiplying function, said magneto-optical recording medium comprising: a substrate; a magnetic film formed on said substrate, said magnetic film having an axis of easy magnetization perpendicular to the magnetic film surface; and a dielectric material layer formed on and in contact with said magnetic film to establish a reflection factor at the magnetic film surface, said reflection factor being about 10% or less.
Claim 2
Dependent Claim
105 words
A magneto-optical recording medium which is adapted for use in a reading system in which a linearly polarized light beam is projected on said medium whereby a light beam reflected by said medium is detected by a photoconductor, said photoconductor having a multiplying function, said magneto-optical recording medium comprising: a substrate; a magnetic film formed on said substrate, said magnetic film having an axis of easy magnetization perpendicular to the magnetic film surface; and a dielectric material layer formed on and in contact with said magnetic film to establish a reflection factor at the magnetic film surface, said reflection factor being about 10% or less.
Claim 3
Dependent Claim
43 words
A magneto-optical recording medium according to claim 1, wherein said dielectric material layer comprises a dielectric material regulating layer consisting of a higher refractive index dielectric material, and a dielectric material alternately-layered structure having alternately layered higher and lower refractive index dielectric layers.
Claim 4
Dependent Claim
36 words
A magneto-optical recording medium according to claim 1, further comprising means for increasing the reflection factor at the back side of the magnetic surface, with respect to the light which has passed through said magnetic film.
Claim 5
Dependent Claim
42 words
A magneto-optical recording medium according to claim 3, wherein said means for increasing the reflection factor comprises a dielectric material multi-layered film provided on the back side of said magnetic film and having alternately layered higher and lower refractive index dielectric materials.
Claim 6
Dependent Claim
25 words
A magneto-optical recording medium according to claim 1, further comprising a protective layer provided on one side of said magnetic film opposite to said substrate.
Claim 7
Dependent Claim
22 words
A magneto-optical recording medium according to claim 1, further comprising a heat insulating layer provided between said substrate and said magnetic film.
References Cited (Backward Citations)
US4412264A
Cited
US4390600A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-26 | 1990-07-28 | 1991-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-26 | 1994-07-28 | 1995-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-26 | 1998-07-28 | 1999-01-27 | $7700.00 | Window Closed / Lapsed |