Patent US5910263A successfully refreshed from Google Patents.
US4497007A
Expired / Lapsed
US
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Magneto-optical storage process
Assignee: Emtec Magnetics GmbH
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Filing: 1982-03-12
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Granted: 1985-01-29
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Expires: 2002-03-12
Abstract
Abstract This invention relates to a magneto-optical storage and playback process for travelling information carriers, by recording on a magnetizable information carrier (1) in the form of a tape, disc or roller while the carrier is in motion, said information carrier having information areas which are larger than 0.2 μm and smaller than 20 μm in one direction of the information plane, the process being carried out by the production of a geometrical structure (4) by the action of the magnetic fields of the recorded information on particles whose greatest length is less than 0.1 μm, preferably 0.02 μm, and by optical scanning of these structures in which light of wavelength 0.38 to 0.8 μm is diffracted on the surface of the moving information carrier (1) and diffraction images are produced which serve for the interpretation of the information.
Inventors
- 👤 Joachim Greiner
- 👤 Burkhard Nippe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:29
CPC Classifications
G; G03; G03G; G03G19/00; G11; G11B; G11B11/00; G11B11/10; G11B11/105
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
245 words
A process for recording and retrieving information of a travelling information carrier including a layer having a magnetic pigment embedded in a binder convertible into a liquid state by chemical or thermal action, the volume filling factor of said layer being less than 0.25 μm and the thickness of the layer equal to or less than 2μ, or two magnetic layers on a substrate, consisting of a lower layer for receiving the magnetic information having pigment or metal, having a layer thickness less than 10 μm and a coercive field greater than 8 kAm -1 and an upper layer, convertible into a liquid state for production of the diffraction structures by the leakage fields of the lower layer, and containing extremely soft magnetic pigment particles and having a coercive field of less than 4 Acm -1 , comprising the steps of (a) recording on said magnetizable information carrier in the form of a tape, disc or roller by modulating it during its movement with information areas which in one direction of the information plane are greater than 0.2 μm and smaller than 20 μm; (b) producing a geometrical structure by the action of the magnetic fields of the recorded information on particles of whose greatest longitudinal dimension is less than 0.1 μm, and (c) optical scanning said structure, defracting light of wavelength 0.38 to 0.8 μm on the surface of the moving information carrier and producing diffraction images which serve for interpretation of the information.
Claim 2
Dependent Claim
245 words
A process for recording and retrieving information of a travelling information carrier including a layer having a magnetic pigment embedded in a binder convertible into a liquid state by chemical or thermal action, the volume filling factor of said layer being less than 0.25 μm and the thickness of the layer equal to or less than 2μ, or two magnetic layers on a substrate, consisting of a lower layer for receiving the magnetic information having pigment or metal, having a layer thickness less than 10 μm and a coercive field greater than 8 kAm -1 and an upper layer, convertible into a liquid state for production of the diffraction structures by the leakage fields of the lower layer, and containing extremely soft magnetic pigment particles and having a coercive field of less than 4 Acm -1 , comprising the steps of (a) recording on said magnetizable information carrier in the form of a tape, disc or roller by modulating it during its movement with information areas which in one direction of the information plane are greater than 0.2 μm and smaller than 20 μm; (b) producing a geometrical structure by the action of the magnetic fields of the recorded information on particles of whose greatest longitudinal dimension is less than 0.1 μm, and (c) optical scanning said structure, defracting light of wavelength 0.38 to 0.8 μm on the surface of the moving information carrier and producing diffraction images which serve for interpretation of the information.
Claim 3
Dependent Claim
25 words
The process as claimed in claim 1, characterised in that recording is carried out using a linear gap so that linear diffraction grids are formed.
Claim 4
Dependent Claim
18 words
In the process as claimed in claim 1 forming a reflection grid together with producing said geometrical structure.
Claim 5
Dependent Claim
26 words
The process as claimed in claim 3, characterised in that recording on an information carrier takes place thermomagnetically by heating above the blocking or Curie temperature.
Claim 6
Dependent Claim
20 words
The process as claimed in claim 4, characterised in that a beam, preferably a laser beam, is used for recording.
Claim 7
Dependent Claim
18 words
The process as claimed in claim 5, characterised in that the information carrier is premagnetised in one direction.
Claim 8
Dependent Claim
28 words
The process as claimed in claim 1, characterised in that recording on a magnetic information carrier is carried out by a binary process with positive to negative saturation.
Claim 9
Dependent Claim
34 words
The process as claimed in claim 1, characterised in that a recording is applied to a magnetic information carrier and is subsequently subjected to a solution of small magnetisable particles which form a structure.
Claim 10
Dependent Claim
35 words
The process as claimed in claim 8, characterised in that the structures formed by the particles are fixed by treatment using a bath or by being sprayed with a soluble or insoluble film forming substance.
Claim 11
Dependent Claim
39 words
The process as claimed in claim 1, characterised in that after production of the magnetic structural arrangement necessary for diffraction, the magnetic information is erased and fresh information is recorded, and the leakage fields thereby produced are magnetically scanned.
Claim 12
Dependent Claim
63 words
The process as claimed in claim 1, characterised in that the information carrier used is a material consisting of a magnetic carrier carrying an original recording, on which carrier movable magnetizable particles are arranged in space at different densities according to the leakage field of the original recording and the resulting layer is subsequently stripped from the carrier which carries the original recording.
Claim 13
Dependent Claim
26 words
The process as claimed in claim 1, characterised in that scanning of the diffraction grid is carried out using monochromatic light, in particular, a laser beam.
Claim 14
Dependent Claim
41 words
The process as claimed in claim 12, characterised in that when scanning is carried out, the angle of diffraction is determined by light-sensitive elements, in particular by optico-electrical transducers situated in the transverse range of the angle of the diffracted light.
Claim 15
Dependent Claim
62 words
The process as claimed in claim 12 characterised in that the process of scanning, the diffracted beam is focussed by an optical system on a point or a line on or at which is situated a light-sensitive element, and in that a neutral wedge is situated in front of the light-sensitive element, whereby different brightness values are associated with the various angles.
Claim 16
Dependent Claim
38 words
The process as claimed in claim 12, characterised in that during scanning, the brightness of the monochromatic source of light is controlled by additional information and that the resulting modulation is also used in the process of scanning.
Claim 17
Dependent Claim
46 words
The process as claimed in claim 1, characterised in that in the process of scanning, the diffraction structures are exposed to a wide band of spectral light, preferably white light, at a fixed angle and in that the diffraction wavelength is scanned at a fixed angle.
Claim 18
Dependent Claim
32 words
The process as claimed in claim 16, characterised in that when white light is used, proportionality exists between the wavelength of light and the magnetic wavelength laid down on the information carrier.
Claim 19
Dependent Claim
36 words
The process as claimed in claims 12 or 16, characterised in that when scanning is carried out with monochromatic or white light, only those diffracted wavelengths belonging to the first diffraction maximum are used for playback.
Claim 20
Dependent Claim
37 words
The process as claimed in claim 17, characterised in that the upper wavelength λ 2 of the wavelength range used for scanning is equal to twice the value of the lower wavelength λ 1 of this range.
Claim 21
Dependent Claim
39 words
The process as claimed in claim 19, characterised in that the light used for scanning has wavelengths in the range of from 0.4 μm to 0.8 μm and the recorded wavelength has values in the range of from ##EQU7##
Claim 22
Dependent Claim
38 words
The process as claimed in claim 16, characterised in that a filter which reproduces the scanned colours at a different intensity is used and in that the intensity is converted into an electric signal by an optico-electrical transducer.
Claim 23
Dependent Claim
23 words
The process as claimed in claim 18, characterised in that intensity fluctuations of the source of light are used for transmitting additional information.
Claim 24
Dependent Claim
23 words
The process as claimed in claim 1, characterised in that a sensor which responds to the wavelength of the diffracted light is used.
Claim 25
Dependent Claim
14 words
The process as claimed in claim 1 wherein said pigment consists of isometric particles.
Claim 26
Dependent Claim
24 words
The process as claimed in claim 1 wherein the information carrier contains a pigment having a coercive field greater than 24 kAm -1 .
Claim 27
Dependent Claim
19 words
The process as claimed in claim 1 wherein simultaneously recording on said carrier and producing said geometrical structure occurs.
Claim 28
Dependent Claim
27 words
The process as claimed in claim 1 including permeating a substrate of the carrier with light and forming a transmission grid together with producing said geometrical structure.
Claim 29
Dependent Claim
24 words
The process as claimed in claim 1 wherein the lower information layer has a magnetically preferred axis perpendicular to the surface of the layer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-29 | 1988-07-30 | 1989-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-29 | 1992-07-30 | 1993-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-29 | 1996-07-30 | 1997-01-29 | $7700.00 | Window Closed / Lapsed |