US4849952A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetooptical information recording apparatus having intensified magnetic flux applying means
Assignee: Canon Inc
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Filing: 1986-09-16
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Granted: 1989-07-18
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Expires: 2006-09-16
Abstract
Abstract A magnetooptical information recording apparatus is provided with a device for irradiating a magnetooptical recording medium with a light beam, and a device for applying a bias magnetic field to a portion, irradiated by the light beam, of the magnetooptical recording medium. The applying device is provided with a yoke member having a first projecting portion positioned in the vicinity of the irradiated portion and a second projecting portion spaced from the first projecting portion in a direction along the surface of the recording medium, wherein the distance of the second projecting portion from the first projecting portion at a closer side to the recording medium is smaller than that at a farther side to the recording medium.
Inventors
- 👤 Makoto Shiho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:54
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10534; G11B11/10536
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
142 words
A magnetooptical information recording apparatus comprising: means for irradiating a magnetooptical recording medium with a light beam; and means for applying a bias magnetic field to a portion of said magnetooptical recording medium irradiated with said light beam, said means for applying comprising a yoke member having a coil wound thereon and including a first projecting portion adapted to be positioned in the vicinity of said irradiated portion, and a pair of second projecting portions positioned at opposite sides of said first projecting portion in a direction along the surface of said recording medium, wherein the distance between each of said second projecting portions and said first projecting portion at a position close to sad recording medium is smaller than the distance between each of said second projecting portions and said first projecting portion at a position farther from said recording medium.
Claim 2
Dependent Claim
142 words
A magnetooptical information recording apparatus comprising: means for irradiating a magnetooptical recording medium with a light beam; and means for applying a bias magnetic field to a portion of said magnetooptical recording medium irradiated with said light beam, said means for applying comprising a yoke member having a coil wound thereon and including a first projecting portion adapted to be positioned in the vicinity of said irradiated portion, and a pair of second projecting portions positioned at opposite sides of said first projecting portion in a direction along the surface of said recording medium, wherein the distance between each of said second projecting portions and said first projecting portion at a position close to sad recording medium is smaller than the distance between each of said second projecting portions and said first projecting portion at a position farther from said recording medium.
Claim 3
Dependent Claim
55 words
A magnetooptical information recording apparatus according to claim 1, satisfying a relation: 0.5d≦δ≦5d wherein d is the distance between the first projecting portion and said magnetooptical recording medium, and δ is the distance between at least one of said second projecting portions and said first projecting portion at the position close to said recording medium.
Claim 4
Dependent Claim
19 words
A magnetooptical information recording apparatus according to claim 2, wherein said distance δ is equal to the distance d.
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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) | 1992-07-17 | 1993-01-16 | 1993-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-17 | 1997-01-16 | 1997-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-17 | 2001-01-16 | 2001-07-18 | $7700.00 | Window Closed / Lapsed |