US3787825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic domain store
Assignee: US Philips Corp
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Filing: 1972-11-06
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Granted: 1974-01-22
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Expires: 1992-11-06
Abstract
Abstract A magnetic store comprising a plate of magnetic material which has a compensation temperature for magnetization, and in which domains are situated in one of two possible positions of functionally determined bit locations. The displacement of a domain from a first position to a second position, or vice versa, is effected under the influence of a thermal-energy carrying beam, which can be positioned on at least one of the bit locations at a time. When the bit locations are heated, the section of a domain becomes strip-like. During cooling a magnetic field is applied which has a direction such that the relevant domain, assuming its original shape again, will be situated in the desired position of the two possible positions. Detection of the information contents is effected by means of light, which is transmitted through a mask which covers half the area of each bit location. The first and second domain positions are defined by elements of a readily magnetizable material or by an additional plate which is filled with domains.
Inventors
- 👤 F Dejonge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:57
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/02; G11; G11C; G11C13/00; G11C13/04; G11C13/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
233 words
A magnetic store comprising a plate of magnetic material on which functionally determined bit locations are provided, each bit location having two positions for each said bit location, and one domain which has a mainly circular section, said magnetic store comprising transport means for controlled displacement of the domain from one of said two positions to the other of said two positions in a chosen bit location, and detection means for detecting the presence of a domain in one of the two positions of a bit location, said plate of magnetic material furthermore having a compensation temperature for magnetization and surrounded by means for keeping the plate at a substantially constant temperature, a radiation source and a beam deflection and addressing system also being provided, said radiation source supplying a thermal-energy carrying beam which is positioned on at least one bit location at a time, and by means of which a quantity of heat is applied to the bit location in a temperature range above the compensation temperature, said heat causing the domain to change from a mainly circular section to a mainly strip-like section, there further being provided a magnetic field source supplying a magnetic field for situating a domain during the cooling in one of said two positions of the bit location thus heated, the relevant domain then changing over again from a mainly strip-like section to a mainly circular section.
Claim 2
Dependent Claim
233 words
A magnetic store comprising a plate of magnetic material on which functionally determined bit locations are provided, each bit location having two positions for each said bit location, and one domain which has a mainly circular section, said magnetic store comprising transport means for controlled displacement of the domain from one of said two positions to the other of said two positions in a chosen bit location, and detection means for detecting the presence of a domain in one of the two positions of a bit location, said plate of magnetic material furthermore having a compensation temperature for magnetization and surrounded by means for keeping the plate at a substantially constant temperature, a radiation source and a beam deflection and addressing system also being provided, said radiation source supplying a thermal-energy carrying beam which is positioned on at least one bit location at a time, and by means of which a quantity of heat is applied to the bit location in a temperature range above the compensation temperature, said heat causing the domain to change from a mainly circular section to a mainly strip-like section, there further being provided a magnetic field source supplying a magnetic field for situating a domain during the cooling in one of said two positions of the bit location thus heated, the relevant domain then changing over again from a mainly strip-like section to a mainly circular section.
Claim 3
Dependent Claim
47 words
The magnetic store as claimed in claim 1, wherein for defining two positions for a domain, there is provided for each bit location, at the area of the bit location, at least one element of a material which can be readily magnetized by said magnetic field source.
Claim 4
Dependent Claim
80 words
The magnetic store as claimed in claim 1 wherein a plurality of said plates of magnetic material are used, at least one bit location at a time being accessible to a beam from the radiation source as a result of said deflection and addressing system and the use of the beam distribution means, so that a said number of domains can be displaced as well as determining their presence in either of the two positions of their relevant bit locations.
Claim 5
Dependent Claim
87 words
The magnetic store of claim 1, wherein an additional plate of magnetic material is provided for defining a first and a second domain position for one domain in each bit location, said additional plate comprising a domain for each of the first and second domain positions in said plate of magnetic material, interaction between domains in the additional plate and domains of said plate of magnetic material ensuring that the latter plate domains are situated in one of the two positions of each bit location thus created.
Claim 6
Dependent Claim
117 words
The magnetic store as claimed in claim 1, wherein said detection means for detecting the presence of a domain in one of the two positions comprises: a light source, the beam of which can be positioned on at least one bit location at a time, the plane of polarization of the light transmitted through the plate or reflected thereby being rotated if it encounters a domain in the plate; a mask which covers, at least in protection, all of either one of the two positions of the bit locations; and at least one light detector by means of which a rotation of the plane of polarization of the light which has passed said mask can be detected.
Claim 7
Dependent Claim
35 words
The magnetic store as claimed in claim 5, wherein for each bit location a light detector is provided by means of which, the information contents of the plate of magnetic material can be made visible.
Claim 8
Dependent Claim
77 words
The magnetic store as claimed in claim 5 wherein said light source is a radiation source for transmitting said thermal-energy carrying beam, the quantity of heat which is applied per bit location, for detection of the positions of the domains in the plate of magnetic material, being smaller than the quantity of heat which is applied per bit location, when a domain is moved from one of said two positions to the other of said two positions.
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) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |