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US3681602A
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Device for detecting and recording electromagnetic radiation including an active magnetic element a parameter of which can be changed by the radiation
Assignee: US Philips Corp
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Filing: 1970-10-19
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Granted: 1972-08-01
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Expires: 1990-10-19
Abstract
Abstract A device for detecting and/or recording electromagnetic radiation which employs as an active element one which responds to the electromagnetic radiation by changing a magnetic parameter thereof such as anisotropy, coercivity or permeability. The active element contains metal ions of which two different energy states as regards a free electron can exist. Ions in one state can absorb energy from electromagnetic radiation to transfer across an energy threshold to the other energy state.
Inventors
- 👤 Richard William Teale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:22
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G02; G02F; G02F1/00; G02F1/0009; G02F1/0036; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/34; H01F1/342; H01F1/344; H01F1/346
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
84 words
A device for detecting and recording electromagnetic radiation comprising an active element consisting of a ferrimagnetic material a magnetic parameter of which can be changed by photons, means to expose the active element to a photon beam, and a magnetic detector to observe the magnetic parameter change, said active element having an ionic crystal structure wherein ions are present on different lattice sites whereby irradiation of the active element with electromagnetic radiation redistributes the ions which modifies the magnetic properties of the active element.
Claim 2
Independent Claim
84 words
A device for detecting and recording electromagnetic radiation comprising an active element consisting of a ferrimagnetic material a magnetic parameter of which can be changed by photons, means to expose the active element to a photon beam, and a magnetic detector to observe the magnetic parameter change, said active element having an ionic crystal structure wherein ions are present on different lattice sites whereby irradiation of the active element with electromagnetic radiation redistributes the ions which modifies the magnetic properties of the active element.
Claim 3
Dependent Claim
16 words
A device according to claim 1, wherein the magnetic parameter observed aS anisotropy, coercivity or permeability.
Claim 4
Dependent Claim
25 words
A device according to claim 2, including a magnet to apply a pre-polarizing magnetic field to the active element for a pre-polarization prior to irradiation.
Claim 5
Dependent Claim
33 words
A device according to claim 1 wherein the active element includes an iron garnet or a spinel ferrite having some iron ions in a divalent state, most being in the normal trivalent state.
Claim 6
Dependent Claim
57 words
A device according to claim 4, wherein the active element includes an iron garnet of the formula M3Fe5 3 (A Fe 2 ) O12 wherein M is an element of the rare earths or a combination thereof and wherein A is an element with a valency different from 3, while 0 delta <1 and 0 < 1.
Claim 7
Dependent Claim
16 words
A device according to claim 5, wherein M is Yttrium, A is Si and delta 0.
Claim 8
Dependent Claim
63 words
A device according to claim 4, wherein the active element includes a spinel ferrite having the formula RFe2 3 - A Fe 2 O4 wherein R is of the group consisting of Ni, Zn, Co, Mg, Mn, and (LiFe) 5 and wherein A is an element with a valency different from 3 with < or = delta <1 and < epsilon < 1.
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) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |