US4599714A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photo-magnetic reproducing apparatus
Assignee: Canon Inc
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Filing: 1983-05-16
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Granted: 1986-07-08
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Expires: 2003-05-16
Abstract
Abstract Disclosed is a photo-magnetic reproducing apparatus in which an incident light beam polarized in a predetermined direction enters a recording medium on which information is magnetically recorded. The light beam from the recording medium is split into two light beams, and a signal containing the information therein is detected from one of the split light beams, while a signal not containing the information therein is detected from the other of the split light beams. The detected two signals are differentiated to thereby obtain an information reproducing signal.
Inventors
- 👤 Kiyonobu Endo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:46
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10541; G11B11/10543; G11B11/10502; G11B11/10515; G11B7/00; G11B7/004; G11B7/005
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
165 words
A photo-magnetic information reproducing apparatus comprising: means for causing a light beam polarized in a predetermined direction to be incident on a recording medium on which information is magnetically recorded; an analyzer; first detecting means positioned for receiving a part of the light beam transmitted from the recording medium through said analyzer, the polarized condition of the light beam being modulated according to the information recorded on the recording medium, said first detecting means further photoelectrically converting said part of the light beam to obtain a first detected signal; second detecting means positioned for receiving the remaining part of the light beam transmitted from the recording medium without passing through said analyzer, said second detecting means photoelectrically converting said remaining part of the light beam to obtain a second detected signal; and means for differentiating said first and second detected signals obtained by said first and second detecting means respectively thereby to obtain an information reproducing signal representing said information recorded on the recording medium.
Claim 2
Dependent Claim
165 words
A photo-magnetic information reproducing apparatus comprising: means for causing a light beam polarized in a predetermined direction to be incident on a recording medium on which information is magnetically recorded; an analyzer; first detecting means positioned for receiving a part of the light beam transmitted from the recording medium through said analyzer, the polarized condition of the light beam being modulated according to the information recorded on the recording medium, said first detecting means further photoelectrically converting said part of the light beam to obtain a first detected signal; second detecting means positioned for receiving the remaining part of the light beam transmitted from the recording medium without passing through said analyzer, said second detecting means photoelectrically converting said remaining part of the light beam to obtain a second detected signal; and means for differentiating said first and second detected signals obtained by said first and second detecting means respectively thereby to obtain an information reproducing signal representing said information recorded on the recording medium.
Claim 3
Dependent Claim
43 words
A photo-magnetic information reproducing apparatus according to claim 1, further comprising light beam splitting means for splitting the light beam transmitted from said recording medium to direct said part thereof and said remaining part thereof to said first and second detecting means, respectively.
Claim 4
Dependent Claim
60 words
A photo-magnetic reproducing apparatus according to claim 2, wherein said light beam splitting means is a polarizing beam splitter having the characteristic of relatively increasing the polarization component, of the light beam travelling toward said first detecting means, which is in a direction perpendicular to said predetermined direction, as compared with the polarization component which is in said predetermined direction.
References Cited (Backward Citations)
JPS5525881A
Cited
US4451863A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-07 | 1990-01-06 | 1990-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-07 | 1994-01-06 | 1994-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-07 | 1998-01-06 | 1998-07-08 | $7700.00 | Window Closed / Lapsed |