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US4497006A
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Magneto-optic recording/playback head assembly
Assignee: Sharp Corp
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Filing: 1982-02-02
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Granted: 1985-01-29
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Expires: 2002-02-02
Abstract
Abstract There is disclosed a head assembly for use in a magneto-optic recording/playback system which includes a memory medium having a magnetic coating having a magnetic anisotropy in a vertical direction. A light beam is applied to the memory medium for recording and reproduction of information. The head assembly includes a polarizing prism and a Faraday effect element in an optical path for the light beam. There is needed only the single polarizer.
Inventors
- 👤 Toshihisa Deguchi
- 👤 Kenji Ohta
- 👤 Akira Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:57
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
69 words
A head assembly for use in a magneto-optic recording/playback system, said system including a memory medium having a magnetic coating having a magnetic anisotropy in a vertical direction and wherein a light beam is applied to the memory medium for recording and reproduction of information, said head assembly comprising a polarizing prism and a Faraday effect element comprising a glass plate in an optical path for said light beam.
Claim 2
Dependent Claim
69 words
A head assembly for use in a magneto-optic recording/playback system, said system including a memory medium having a magnetic coating having a magnetic anisotropy in a vertical direction and wherein a light beam is applied to the memory medium for recording and reproduction of information, said head assembly comprising a polarizing prism and a Faraday effect element comprising a glass plate in an optical path for said light beam.
Claim 3
Dependent Claim
20 words
The head assembly of claim 1, wherein said Faraday effect element comprises a glass plate having an amorphous molecular structure.
Claim 4
Dependent Claim
20 words
The head assembly of claim 1, wherein said Faraday effect element comprises a glass plate surrounded by a cylindrical magnet.
Claim 5
Dependent Claim
20 words
The head assembly of claim 3, wherein said magnet develops a magnetic field in a direction parallel to said path.
References Cited (Backward Citations)
US3838907A
Cited
US4409631A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-29 | 1988-07-30 | 1989-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-29 | 1992-07-30 | 1993-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-29 | 1996-07-30 | 1997-01-29 | $7700.00 | Window Closed / Lapsed |