US3739359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic buffer storage
Assignee: EIDP Inc
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Filing: 1971-08-25
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Granted: 1973-06-12
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Expires: 1991-08-25
Abstract
Abstract A buffer storage system is described in which the storage element is composed of a magneto-opticmirror having a layer of a low-Curie temperature magnetic material on one face. Information can be read into the layer of low Curie temperature by thermomagnetic methods without disturbing previous information on the magneto-opticmirror, then transferred to the magnetooptic layer by a suitable transfer field (either a decaying oscillating field or a pulsed unidirectional field) at a predetermined time in response to trigger signals.
Inventors
- 👤 R Waring
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:52
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/06
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
173 words
Apparatus for the buffer storage of information comprising: i. a compound magnetic member having a first magnetic layer of a hard magnetic material and a second magnetic mirror layer having a thickness less than 1,000 A adjacent said first layer having magnetic properties including a coercivity greater than the magnetic field of signals recorded on said first magnetic layer but less than the coercivity of said first magnetic layer, said second mirror layer being within the local field generated by magnetic signals on said first magnetic layer; ii. thermomagnetic means to form magnetic images corresponding to information on said first magnetic layer without affecting said magnetic mirror layer; iii. means to apply magnetic fields to said compound magnetic member, including transfer means for intermittently applying bursts of magnetic field to said compound member in response to triggering signals to transfer magnetic images from said first magnetic layer to said mirror layer; iv. triggering means for triggering said transfer means; and v. means to read out magnetic signals on said second magnetic mirror layer.
Claim 2
Dependent Claim
173 words
Apparatus for the buffer storage of information comprising: i. a compound magnetic member having a first magnetic layer of a hard magnetic material and a second magnetic mirror layer having a thickness less than 1,000 A adjacent said first layer having magnetic properties including a coercivity greater than the magnetic field of signals recorded on said first magnetic layer but less than the coercivity of said first magnetic layer, said second mirror layer being within the local field generated by magnetic signals on said first magnetic layer; ii. thermomagnetic means to form magnetic images corresponding to information on said first magnetic layer without affecting said magnetic mirror layer; iii. means to apply magnetic fields to said compound magnetic member, including transfer means for intermittently applying bursts of magnetic field to said compound member in response to triggering signals to transfer magnetic images from said first magnetic layer to said mirror layer; iv. triggering means for triggering said transfer means; and v. means to read out magnetic signals on said second magnetic mirror layer.
Claim 3
Dependent Claim
66 words
Apparatus of claim 1 wherein said means to form magnetic images comprises an electron beam directed on said first magnetic layer, means to apply a bias magnetic field to said first magnetic layer, and means to modulate said electron beam and said magnetic bias means whereby a magnetic image is formed by the combined action of heating by the electron beam and the bias magnetic field.
Claim 4
Dependent Claim
81 words
Apparatus of claim 2 in which the means to read out the magnetic signals on said mirror layer comprises a source of polarized light adapted and arranged to project polarized light onto the surface of the mirror layer opposite said first magnetic layer, whereby the polarization of the light is modulated by the magneto-optic effect on reflection from said mirror layer, and means to detect the modulation of the polarization of the light reflected by said mirror layer from said source.
Claim 5
Dependent Claim
47 words
Apparatus of claim 3 in which said mirror layer has an easy axis of magnetization and the magnetic image is formed by modulation of the magnetization of said first magnetic layer in the plane of said first magnetic layer and parallel to the easy axis of magnetization.
Claim 6
Dependent Claim
36 words
Apparatus of claim 4 in which said biasing means is adapted and arranged to apply bursts of magnetic field to the said compound magnetic member directed along the easy axis of magnetization of said mirror layer.
Claim 7
Dependent Claim
80 words
Apparatus of claim 5 in which said bursts consists of a decaying oscillating magnetic field which has a field strength which is gradually reduced from a maximum level substantially producing magnetic saturation of said mirror layer to a minimum level which is below the coercivity of said mirror layer, whereby said mirror layer is remanently magnetized imagewise in accordance with the local surface field applied to said mirror layer by said first magnetic laYer at the time of said burst.
Claim 8
Dependent Claim
13 words
Apparatus of claim 6 additionally comprising means to premagnetize said first magnetic layer.
Claim 9
Dependent Claim
52 words
Apparatus of claim 7 wherein said means to premagnetize said first magnetic layer includes radiant electromagnetic energy means to transiently heat the magnetic material of said first magnetic layer to the vicinity of the Curie temperature and means to apply a magnetic field to said first magnetic layer during the transient heating.
Claim 10
Dependent Claim
40 words
The apparatus of claim 4 in which said biasing means is adapted and arranged to produce bursts of magnetic field directed in the plane of the mirror layer and perpendicular to the easy axis of magnetization of said mirror layer.
Claim 11
Dependent Claim
81 words
Apparatus of claim 9 in which said bursts consist of a decaying oscillating magnetic field which has a field strength which is gradually reduced from a maximum level substantially producing magnetic saturation of said mirror layer to a minimum level which is below the anisotropy field of said mirror layer, whereby said mirror layer is remanently magnetized imagewise in accordance with the local surface field applied to said mirror layer by said first magnetic layer at the time of said burst.
Claim 12
Dependent Claim
13 words
Apparatus of claim 10 additionally comprising means to premagnetize said first magnetic layer.
Claim 13
Dependent Claim
52 words
Apparatus of claim 11 wherein said means to premagnetize said first magnetic layer includes radiant electromagnetic energy means to transiently heat the magnetic material of said first magnetic layer to the vicinity of the Curie temperature and means to apply a magnetic field to said first magnetic layer during the transient heating.
Claim 14
Independent Claim
230 words
A method for the buffer storage of information which comprises; transiently heating a first magnetic layer of a compound recording member with a modulated beam of radiation under magnetic field conditions whereby a magnetic image corresponding to said information is recorded as a pattern of magnetization on said recording member, said compound recording member comprising a first hard magnetic layer and a second mirror magnetic layer having a thickness of less than 1,000 A and having a coercivity less than the coercivity of said first magnetic layer, disposed in the magnetic field of said first magnetic layer; said magnetic conditions consisting of magnetic fields less than the coercivity of said second layer, said heating being to the vicinity of the Curie temperature whereby the coercivity of said first magnetic layer is transiently reduced to a value below the strength of said fields, and applying a burst of electromagnetic radiation to said compound recording member whereby the magnetic image on said second magnetic layer is imagewise magnetized corresponding to the image on said first magnetic layer; said image on said second magnetic layer being retained while a subsequent image is recorded on said first magnetic layer, reflecting a beam of polarized light from said second magnetic layer and detecting the imagewise modulation of the plane of polarization of light reflected from said second mirror layer by the pattern of magnetization thereon.
Claim 15
Independent Claim
230 words
A method for the buffer storage of information which comprises; transiently heating a first magnetic layer of a compound recording member with a modulated beam of radiation under magnetic field conditions whereby a magnetic image corresponding to said information is recorded as a pattern of magnetization on said recording member, said compound recording member comprising a first hard magnetic layer and a second mirror magnetic layer having a thickness of less than 1,000 A and having a coercivity less than the coercivity of said first magnetic layer, disposed in the magnetic field of said first magnetic layer; said magnetic conditions consisting of magnetic fields less than the coercivity of said second layer, said heating being to the vicinity of the Curie temperature whereby the coercivity of said first magnetic layer is transiently reduced to a value below the strength of said fields, and applying a burst of electromagnetic radiation to said compound recording member whereby the magnetic image on said second magnetic layer is imagewise magnetized corresponding to the image on said first magnetic layer; said image on said second magnetic layer being retained while a subsequent image is recorded on said first magnetic layer, reflecting a beam of polarized light from said second magnetic layer and detecting the imagewise modulation of the plane of polarization of light reflected from said second mirror layer by the pattern of magnetization thereon.
Claim 16
Dependent Claim
32 words
Method of claim 13 wherein said first magnetic layer is premagnetized and said magnetization is recorded by modulating the intensity and position of said beam of radiation in accordance with said information.
Claim 17
Dependent Claim
41 words
Method of claim 14 wherein a magnetic field having a strength less than the coercivity of said second mirror layer and opposed to the premagnetization of said first magnetic layer is applied to said compound magnetic recording member during said heating.
Claim 18
Dependent Claim
55 words
Method of claim 13 wherein said first magnetic layer is initially unmagnetized and said information is recorded by modulating the intensity and position of said beam of radiation in accordance with said information while applying a magnetic field having a strength less than the coercivity of said second magnetic layer to said compound recording member.
Claim 19
Dependent Claim
48 words
Method of claim 13 wherein said beaM of radiation is scanned spatially on said recording member, while applying a magnetic field having a maximum strength less than the coercivity of said second magnetic layer to said recording member and modulating said magnetic field in accordance with said information.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |