Patent US3665431A successfully refreshed from Google Patents.
US3665431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magneto-optic transducer
Assignee: International Business Machines Corp
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Filing: 1970-06-25
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Granted: 1972-05-23
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Expires: 1990-06-25
Abstract
Abstract Disclosed herein is a new magneto-optic transducer which orients the transfer film non-parallel to the record storage medium with only an edge of the transfer film adjacent the record storage medium. The magneto-optic transducer also provides a reflecting surface adjacent the surface of the record storage medium on either side of the transfer film so that the magneto-optic Kerr or Faraday Effect may be utilized with the transducer. Furthermore, the reflecting surface permits a focused light beam to be directed near the edge of the transfer film adjacent the storage medium.
Inventors
- 👤 John K Alstad
- 👤 John D Armitage Jr
- 👤 Geoffrey Bate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:29
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10541; G11B11/10543; G11B11/10547; G02; G02F; G02F1/00; G02F1/01; G02F1/09
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
186 words
A magneto-optic transducer for converting variations in magnetization in a magnetic storage medium into variations in a light beam comprising: a first light transparent member mounted with a first face adjacent to and a second face non-parallel to the surface of the magnetic storage medium; a second light transparent member mounted with a first face adjacent to and a second face non-parallel to the surface of the magnetic storage medium; a thin magneto-optic transfer film mounted between said second faces of said transparent members whereby said film is nonparallel to the surface of the magnetic storage medium; said film having one edge adjacent the surface of the storage medium so that said film is magnetized in accordance with the magnetization in the area of the storage medium adjacent the edge of said film; said light transparent members having an index of refraction such that total internal reflection will occur at the faces of said members adjacent the magnetic storage medium whereby light can enter said first member, magneto-optically interact with magnetization in said film and be reflected back out of either said first or second member.
Claim 2
Dependent Claim
186 words
A magneto-optic transducer for converting variations in magnetization in a magnetic storage medium into variations in a light beam comprising: a first light transparent member mounted with a first face adjacent to and a second face non-parallel to the surface of the magnetic storage medium; a second light transparent member mounted with a first face adjacent to and a second face non-parallel to the surface of the magnetic storage medium; a thin magneto-optic transfer film mounted between said second faces of said transparent members whereby said film is nonparallel to the surface of the magnetic storage medium; said film having one edge adjacent the surface of the storage medium so that said film is magnetized in accordance with the magnetization in the area of the storage medium adjacent the edge of said film; said light transparent members having an index of refraction such that total internal reflection will occur at the faces of said members adjacent the magnetic storage medium whereby light can enter said first member, magneto-optically interact with magnetization in said film and be reflected back out of either said first or second member.
Claim 3
Dependent Claim
30 words
The magneto-optic transducer of claim 1 wherein said light transparent members have faces normal to the light path of the light beam as the light enters and leaves the transducer.
Claim 4
Dependent Claim
35 words
The magneto-optic transducer of claim 1 wherein said light transparent members have a curvature on the faces adjacent the magnetic storage medium so that flying height between the medium and the transducer may be reduced.
Claim 5
Dependent Claim
39 words
The magneto-optic transducer of claim 1 wherein said light transparent members have slots cut in the faces of said members adjacent the magnetic storage medium so that the flying height between the medium and the transducer may be reduced.
Claim 6
Dependent Claim
21 words
The magneto-optic transducer of claim 1 wherein said thin film is multilayered having Alternate layers of ferromagnetic material and dielectric material.
Claim 7
Dependent Claim
68 words
The magneto-optic transducer of claim 1 and in addition a reflective film attached to the faces of the light transparent members adjacent the magnetic storage medium whereby total internal reflection will still occur irrespective of close contact between the storage medium and the faces of said members or irrespective of the angle of incidence of the light beam on the faces of said members adjacent the storage medium.
Claim 8
Dependent Claim
29 words
The magneto-optic transducer of claim 1 and in addition a source of bias magnetic field to aid the transfer of magnetization from the storage medium to the transfer film.
Claim 9
Dependent Claim
116 words
A magneto-optic transducing element for converting variations in magnetization into variations in a light beam comprising: a magneto-optic transfer film mounted 90* + or - 15* to the surface of the magnetic source medium being read out, said film being approximately 200 to 500 Angstrom units thick; a light transparent member bonded to one side of said film and having a first face normal to a light path which has an angle of incidence to the thin film of 42* + or - 5*, said light transparent member also having a second face normal to the path of the light reflected first from the thin film and subsequently from the bottom of the light transparent member.
Claim 10
Dependent Claim
116 words
A magneto-optic transducing element for converting variations in magnetization into variations in a light beam comprising: a magneto-optic transfer film mounted 90* + or - 15* to the surface of the magnetic source medium being read out, said film being approximately 200 to 500 Angstrom units thick; a light transparent member bonded to one side of said film and having a first face normal to a light path which has an angle of incidence to the thin film of 42* + or - 5*, said light transparent member also having a second face normal to the path of the light reflected first from the thin film and subsequently from the bottom of the light transparent member.
Claim 11
Dependent Claim
61 words
The magneto-optic transducing element of claim 8 and in addition a second light transparent member bonded to the other side of said thin film for internally reflecting light passed through the thin film, said second member having a face normal to the path of the light passed by said film and reflected from the bottom of said second light transparent member.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |