US3905040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic domain storage disk
Assignee: US Philips Corp
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Filing: 1974-01-16
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Granted: 1975-09-09
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Expires: 1994-01-16
Abstract
Abstract A storage system uses a plate of magnetic material having a twodimensional regular array of positions in which a domain can each time be written and read by light radiation. The plate rotates at a uniform speed, while positioning members can be selectively controlled in the radial direction. The light is generated, for example, by a laser.
Inventors
- 👤 Matti Nillo Tapani Otala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:26
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/38; G11B23/40; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11C; G11C13/00; G11C13/04; G11C13/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
A storage system comprising a plate of magnetic material in which digital information can be stored in the form of domains, a plurality of magnetically active elements for determining a number of domain positions, write means from storing domains under the influence of thermal action of electromagnetic radiation, means for maintaining a magnetic bias field whose magnitude determines the domain dimension, the improvement wherein said plate is located on a rotatable disk, drive means for rotating said disk At a substantially uniform speed, said write means including read means for retrieving said information by electromagnetic radiation, and positioning members for selectively addressing the radial position of a domain on said disk.
Claim 2
Dependent Claim
111 words
A storage system comprising a plate of magnetic material in which digital information can be stored in the form of domains, a plurality of magnetically active elements for determining a number of domain positions, write means from storing domains under the influence of thermal action of electromagnetic radiation, means for maintaining a magnetic bias field whose magnitude determines the domain dimension, the improvement wherein said plate is located on a rotatable disk, drive means for rotating said disk At a substantially uniform speed, said write means including read means for retrieving said information by electromagnetic radiation, and positioning members for selectively addressing the radial position of a domain on said disk.
Claim 3
Dependent Claim
69 words
A storage system as claimed in claim 1, wherein said plate comprises recesses in the layer of magnetic material which form, together with said positions, a regular array which is arranged according to at least substantially circular tracks, said recesses being arranged according to centering tracks, centering means being provided by means of which electromagnetic radiation can be projected on said centering tracks and can be detected after reflection.
Claim 4
Dependent Claim
36 words
A storage system as claimed in claim 1, wherein said positioning means comprises a logic member, means for supplying said reflected electromagnetic radiation to said logic member, said radial position being addressable by said logic member.
Claim 5
Dependent Claim
33 words
A storage system as claimed in claim 1, wherein said means for maintaining a magnetic bias field comprise a layer of permanent magnetic material which is provided on said plate of magnetic material.
Claim 6
Dependent Claim
26 words
A storage system as claimed in claim 1, wherein said magnetically active elements contain dot-like soft-magnetic material which is deposited on the plate of magnetic material.
Claim 7
Dependent Claim
64 words
A storage system as claimed in claim 1, wherein the operating temperature of said plate of magnetic material is below its compensation temperature, characterized in that said write means comprise a preheater and a light source which can be modulated, the said light source not being capable but light source and preheater together being capable of locally raising the temperature to the compensation temperature.
Claim 8
Dependent Claim
94 words
A storage system as claimed in claim 1, wherein the operating temperature of said plate of magnetic material lies below its compensation temperature, characterized in that said write means comprise a magnetic field generator and a light source which can be modulated, in which the temperature of the plate of magnetic material can be locally increased to the compensation temperature which is dependent of the magnet field strength by cooperation of the additional magnetic field generated by the magnetic field generator, which counteracts the magnetic bias field, and the radiation of said light source.
Claim 9
Dependent Claim
60 words
A storage disk to be used in a storage system as claimed in claim 1, wherein the storage disk can be removed from the storage system together with means incorporated therein for maintaining a magnetic bias field, the storage disk comprising mechanical centering means which can cooperate in a centring manner with non-removable second centering means of the storage system.
Claim 10
Dependent Claim
53 words
A storage cassette to be used in a storage system as claimed in claim 1, wherein it can be removed from the system, together with means for maintaining a magnetic bias field in the interior thereof which are incorporated therein, and that it contains a storage disk in which domains can be formed.
References Cited (Backward Citations)
US3793639A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |