US3838907A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetisable material for detecting or recording electromagnetic radiation
Assignee: US Philips Corp
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Filing: 1972-12-26
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Granted: 1974-10-01
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Expires: 1992-12-26
Abstract
Abstract A device for detecting electromagnetic radiation and for recording by means of electromagnetic radiation which employs an active element of a ferrimagnetic material having a garnet or spinel structure, which is kept in the dark and responds to irradiation with electromagnetic radiation, particularly infrared and X-ray radiation, by increasing at an essentially constant temperature below the Curie-point the coercivity or decreasing the permeability thereof.
Inventors
- 👤 U Enz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:35
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10515; G01; G01T; G01T1/00; G01T1/16; G02; G02F; G02F1/00; G02F1/01; G02F1/09; G03; G03G; G03G5/00; G03G5/16; G11B11/10532; G11B11/10534; G11B11/10539; G11B11/10541; G11B11/10543; G11B11/11
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
156 words
A device for detecting electro-magnetic radiation and recording by means of electromagnetic radiation comprising an active element of ferrimagnetic material having a garnet or spinel structure having a given coercive force and a given permeability in the dark, a source of electromagnetic radiation for providing a radiation beam of a wavelength smaller than 1 X 10 5 m, means for directing the radiation beam onto the active element to produce therein a change in coercive force or magnetic permeability, a first magnet to apply to the active element during or after exposure a magnetic field and read-out means including a source for providing a linearly polarized light beam of a wavelength and intensity which does not affect the magnetic properties of the active element, means allowing the polarized light beam to impinge on the active element, and a detector which is responsive to the rotation of the plane of polarisation in the transmitted or reflected beam.
Claim 2
Independent Claim
156 words
A device for detecting electro-magnetic radiation and recording by means of electromagnetic radiation comprising an active element of ferrimagnetic material having a garnet or spinel structure having a given coercive force and a given permeability in the dark, a source of electromagnetic radiation for providing a radiation beam of a wavelength smaller than 1 X 10 5 m, means for directing the radiation beam onto the active element to produce therein a change in coercive force or magnetic permeability, a first magnet to apply to the active element during or after exposure a magnetic field and read-out means including a source for providing a linearly polarized light beam of a wavelength and intensity which does not affect the magnetic properties of the active element, means allowing the polarized light beam to impinge on the active element, and a detector which is responsive to the rotation of the plane of polarisation in the transmitted or reflected beam.
Claim 3
Dependent Claim
22 words
A device according to claim 1, wherein infrared light is used for recording and wherein visible light is used for reading out.
Claim 4
Dependent Claim
21 words
A device according to claim 1, wherein X-rays are used for recording and wherein visible light is used for reading out.
Claim 5
Dependent Claim
39 words
A device according to claim 3, wherein the active element is present in the form of a thin layer, applied to the inner surface of a hollow hemisphere, in the centre of which a crystal may be rotatably positioned.
Claim 6
Dependent Claim
18 words
A device according to claim 1, including erasing means comprising a heat source for heating the active element.
References Cited (Backward Citations)
US3447851A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |