EP0096504A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Aurous archival record films for digital data storage
Assignee: Unisys Corp
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Filing: 1983-05-24
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Granted: —
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Expires: 2003-05-24
Abstract
Abstract An optical data storage system is contemplated, one employing a data-modulated writing laser beam and a non-erasing reading laser (L) beam of predetermined wavelength. Improved optical media for such systems are described, these characterized by multiple layers whose optical characteristics and thickness are chosen to accommodate a prescribed writing and reading energy and wavelength and so provide an anti-reflection condition for unrecorded portions of the medium and a relatively higher reflectivity for recorded portions. A preferred optical medium includes a highly reflective aluminum layer, (3) a relatively transparent dielectric spacer layer (4) overlying the reflective layer, and an Au-Sn absorber layer (5) overlying the nucleation layer, the absorber layer (5) being rendered in island configuration, adapted to be so affected by the contemplated write beam as to "agglomerate" and better transmit the read beam.
Inventors
- 👤 Craig Martin Shevlin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 11:37
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24306; G11B2007/24308; G11B2007/24312; G11B2007/24314; G11B2007/24316; G11B7/252; G11B7/257; G11B2007/25705; G11B2007/2571; G11B2007/25715; G11B7/253; G11B7/2533; G11B7/258; G11B7/2585
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
187 words
In an optical data storage system, the combination comprising: an archival optical recording medium on a dielectric substrate layer; means for providing recording radiation of a prescribed wavelength; means for modulating said radiation to present a prescribed minimum write-energy level in accordance with applied data; means for focusing the so-modulated radiation in a prescribed beam upon said recording medium; and means providing for relative movement between the focused recording beam and said recording medium; said recording medium being adapted for read-out with a like radiation beam, of reduced power level however, the medium comprising at least one ultra-thin, discontinuous layer of gold alloy absorber material deposited in island form so as to be "agglomerated" upon application of said beam at said write-energy level at prescribed bit sites of said medium whereby to alter an optical characteristic thereof during said movement, for detection by associated read-out means; said island-film presenting well separated "islands" of the absorber material having an average width very considerably smaller than the width of said beam, the gold alloy comprising a minor portion of tin, sufficient to promote improved adhesion to the substrate layer.
Claim 2
Dependent Claim
187 words
In an optical data storage system, the combination comprising: an archival optical recording medium on a dielectric substrate layer; means for providing recording radiation of a prescribed wavelength; means for modulating said radiation to present a prescribed minimum write-energy level in accordance with applied data; means for focusing the so-modulated radiation in a prescribed beam upon said recording medium; and means providing for relative movement between the focused recording beam and said recording medium; said recording medium being adapted for read-out with a like radiation beam, of reduced power level however, the medium comprising at least one ultra-thin, discontinuous layer of gold alloy absorber material deposited in island form so as to be "agglomerated" upon application of said beam at said write-energy level at prescribed bit sites of said medium whereby to alter an optical characteristic thereof during said movement, for detection by associated read-out means; said island-film presenting well separated "islands" of the absorber material having an average width very considerably smaller than the width of said beam, the gold alloy comprising a minor portion of tin, sufficient to promote improved adhesion to the substrate layer.
Claim 3
Dependent Claim
136 words
The invention in accordance with claim 1, including means for providing a reading radiation beam having a predetermined wavelength and a width corresponding with that of said record beam, and wherein said means for focusing and said means providing for relative movement are also employed for, respectively, focusing the reading beam upon said medium and for providing said relative movement; and wherein said alteration in optical characteristic of said medium is chosen and adapted, in conjunction with the energy-level and wavelength of said reading beam such that, during relative movement between the focused reading beam and said medium, the radiation reflected from said medium varies in accordance with the so-recorded data, the read-energy level of said reading beam additionally being chosen so that it does not significantly affect the subsequent readability of said data-indicating optical alterations.
Claim 4
Dependent Claim
161 words
In an optical data storage system, the combination comprising: an archival optical medium having data recorded thereon as a series of optically detectable changes in said medium; means for providing a reading radiation beam having a predetermined wavelength and write-energy level; means for focusing said reading beam on said medium; and means providing for relative movement between the focused reading beam and said medium; said medium comprising at least one discontinuous layer of gold alloy absorber material deposited in island form on a dielectric substrate means so as to "agglomerate" upon application of said reading beam at said write-energy level at prescribed bit sites of said medium whereby to so detectably alter an optical characteristic thereof during said movement as to accommodate a prescribed detection by associated read-out means, said layers presenting well-segmented "islands" of the absorber materials the islands having an average width considerably smaller than the width of said beam; said gold alloy including a minor portion of tin.
Claim 5
Dependent Claim
161 words
In an optical data storage system, the combination comprising: an archival optical medium having data recorded thereon as a series of optically detectable changes in said medium; means for providing a reading radiation beam having a predetermined wavelength and write-energy level; means for focusing said reading beam on said medium; and means providing for relative movement between the focused reading beam and said medium; said medium comprising at least one discontinuous layer of gold alloy absorber material deposited in island form on a dielectric substrate means so as to "agglomerate" upon application of said reading beam at said write-energy level at prescribed bit sites of said medium whereby to so detectably alter an optical characteristic thereof during said movement as to accommodate a prescribed detection by associated read-out means, said layers presenting well-segmented "islands" of the absorber materials the islands having an average width considerably smaller than the width of said beam; said gold alloy including a minor portion of tin.
Claim 6
Dependent Claim
136 words
An archival optical medium for use in an optical data storage system capable of providing a data-modulated focused write-beam of recording radiation on said medium, while providing relative movement therebetween, said beam being data-modulated to present pulses of prescribed write-energy representing data bits; said medium comprising at least one layer of gold alloy absorber material deposited in discontinuous island form on a dielectric layer so as to be "agglomerated" upon application of said beam pulses at prescribed bit sites thereon whereby to detectably alter an optical characteristic there during said movement so as to facilitate read-out by prescribed associated optical detect means, the island-layers so formed presenting well-segmented "islands" of absorber material having an average width considerably smaller than the width of said beam; said gold alloy including sufficient tin to improve adhesion and optical properties.
Claim 7
Dependent Claim
136 words
An archival optical medium for use in an optical data storage system capable of providing a data-modulated focused write-beam of recording radiation on said medium, while providing relative movement therebetween, said beam being data-modulated to present pulses of prescribed write-energy representing data bits; said medium comprising at least one layer of gold alloy absorber material deposited in discontinuous island form on a dielectric layer so as to be "agglomerated" upon application of said beam pulses at prescribed bit sites thereon whereby to detectably alter an optical characteristic there during said movement so as to facilitate read-out by prescribed associated optical detect means, the island-layers so formed presenting well-segmented "islands" of absorber material having an average width considerably smaller than the width of said beam; said gold alloy including sufficient tin to improve adhesion and optical properties.
Claim 8
Dependent Claim
139 words
The invention in accordance with claim 1, 2, 3 or 4, wherein said radiation is from a laser source; wherein said medium comprises a plurality of layers including a reflective layer, a radiation=transparent dielectric spacer layer overlying said reflective layer, and an absorber layer, or layers, in island form overlying said spacer layer, the thicknesses and optical characteristics of said layers and the optically detectable changes of said absorber layer(s) being chosen, in conjunction with the energy-level and wavelength of the associated reading laser such that, during relative movement between the focused reading laser beam and said medium, the reading laser reflects a read-beam from said medium which will vary in accordance with the data so recorded, the intensity of said-read beam additionally being chosen so as to not significantly degrade the subsequent readability of the so-altered optical characteristic.
Claim 9
Dependent Claim
22 words
The invention in accordance with claim 5 wherein said absorber island layers are deposited by evaporation from a melt in a vacuum.
Claim 10
Dependent Claim
26 words
The invention in accordance with claim 6 wherein the overall thickness of said absorber island layers is the order of a few hundred Angstroms or less.
Claim 11
Dependent Claim
14 words
The invention in accordance with claim 7, wherein said polymer spacer layer comprises polytetrafluoroethylene.
Claim 12
Dependent Claim
53 words
The invention in accordance with claims 2, 3 or 4, wherein the medium is fabricated by providing an anti-reflection base on which the island layers are deposited, whereby a prescribed minimal reflectance is exhibited by unrecorded portions of the medium, said base including a transparent polymer surface for deposition of the absorber layers.
Claim 13
Dependent Claim
22 words
The invention as recited in claim 9, wherein said island layers are deposited only until yielding a prescribed initial minimal reflectance value.
Claim 14
Dependent Claim
19 words
The invention as recited in claim 10, wherein the island layers are so vapor deposited while monitoring reflectance thereof.
Claim 15
Dependent Claim
53 words
The invention as recited in claims 1,3 or 4, wherein said island layers are so deposited on a polymer substrate and are thus adapted to conserve write energy incident on said bit sites during such recording whereby to facilitate low-powerllow-temperature recording, without. need to heat the absorber material to its bulk melting temperature.
Claim 16
Dependent Claim
41 words
The invention as recited in claims 1,..3 or 4, wherein the average size and spacing of the islands so rendered is selected and adapted to facilitate such "agglomeration" during such recording whereby to significantly shift reflectance at each so-recorded bit site.
Claim 17
Dependent Claim
38 words
The invention as recited in claims 1, 3 or 4, wherein the island layers are so formed as to yield such changes upon recording, yet without necessarily involving any significant expulsion of absorber material from a recorded bit-site.
Claim 18
Dependent Claim
36 words
The invention as recited in claim 1, 3 or 4, wherein the island layers are covered with a protective defocusing overcoat and are deposited upon a clear thermally-insulative polymer serving as part of an anti-reflective base.
Claim 19
Dependent Claim
38 words
The invention as recited in claim 15, wherein a tin strike is first deposited on the polymer; then an antimony strike, then one or more deposits of gold as a gold alloy, all deposits being in island form.
Claim 20
Independent Claim
183 words
A method of fabricating an archival medium for optical data storage medium for use in an optical storage system, the system providing a data-modulated laser write-beam of predetermined wavelength and prescribed write-energy with this beam to be focused upon said medium while relative movement is provided therebetween, said method including the steps of: providing a reflective support means having thereon a prescribed clear polymer spacer layer; and depositing at least one thin strike of tin or a tin alloy in island-form over said spacer layer; depositing one or more layers of gold or a gold alloy on the tin islands; the thicknesses and optical characteristics of said layers being chosen so that, at said write- wavelength, an anti-reflection condition will prevail on unrecorded portions of said medium; the thicknesses and optical characteristics of said layers being further chosen so that said data-modulation of the write-beam applies a prescribed write-pulse at said write-energy at selected bit-sites of said absorber layers, irradiating each such site sufficient to detectably disturb the anti-reflection condition thereat and so alter its optical characteristics as to facilitate prescribed optical read-out.
Claim 21
Independent Claim
183 words
A method of fabricating an archival medium for optical data storage medium for use in an optical storage system, the system providing a data-modulated laser write-beam of predetermined wavelength and prescribed write-energy with this beam to be focused upon said medium while relative movement is provided therebetween, said method including the steps of: providing a reflective support means having thereon a prescribed clear polymer spacer layer; and depositing at least one thin strike of tin or a tin alloy in island-form over said spacer layer; depositing one or more layers of gold or a gold alloy on the tin islands; the thicknesses and optical characteristics of said layers being chosen so that, at said write- wavelength, an anti-reflection condition will prevail on unrecorded portions of said medium; the thicknesses and optical characteristics of said layers being further chosen so that said data-modulation of the write-beam applies a prescribed write-pulse at said write-energy at selected bit-sites of said absorber layers, irradiating each such site sufficient to detectably disturb the anti-reflection condition thereat and so alter its optical characteristics as to facilitate prescribed optical read-out.
Claim 22
Dependent Claim
34 words
The invention in accordance with claim 17, wherein said absorber layers are deposited by vapor deposition only until a prescribed low-reflectance level is first detected; and wherein an antimony strike follows the tin strike.
Claim 23
Independent Claim
203 words
A method of preparing improved archival radiation- recording record blanks wherein an information layer is disposed on polymeric substrate means and is adapted to record digital data bits by application of a radiant energy write-beam of prescribed write-energy and wavelength, this method including the steps of: depositing gold or gold alloy "absorber material" in insular form to a prescribed relatively miniscule depth on the substrate means such as to constitute a discontinuous record-film exhibiting an array of separated "islands" and having a prescribed virginal-reflectance so as to appear "optically- continuous" to said write-beam; whereby such a write-beam may be so applied to "bit sites" therein and be data-modulated to apply prescribed write-pulses at said write-energy at selected sites and there induce a prescribed "agglomeration" of the absorber islands to make the film appear more discontinuous optically and optically- apertured there, and to thereby shift the detected reflectance of each so-written site to represent said data; the absorber material being selected and so vapor-deposited, in conjunction with the surrounding optical/thermal environment, as to so "agglomerate"; this absorber island deposit being preceded however by a light island-strike of tin, sufficient to promote good adhesion to the polymeric substrate means and to promote improved optical properties.
Claim 24
Independent Claim
203 words
A method of preparing improved archival radiation- recording record blanks wherein an information layer is disposed on polymeric substrate means and is adapted to record digital data bits by application of a radiant energy write-beam of prescribed write-energy and wavelength, this method including the steps of: depositing gold or gold alloy "absorber material" in insular form to a prescribed relatively miniscule depth on the substrate means such as to constitute a discontinuous record-film exhibiting an array of separated "islands" and having a prescribed virginal-reflectance so as to appear "optically- continuous" to said write-beam; whereby such a write-beam may be so applied to "bit sites" therein and be data-modulated to apply prescribed write-pulses at said write-energy at selected sites and there induce a prescribed "agglomeration" of the absorber islands to make the film appear more discontinuous optically and optically- apertured there, and to thereby shift the detected reflectance of each so-written site to represent said data; the absorber material being selected and so vapor-deposited, in conjunction with the surrounding optical/thermal environment, as to so "agglomerate"; this absorber island deposit being preceded however by a light island-strike of tin, sufficient to promote good adhesion to the polymeric substrate means and to promote improved optical properties.
Claim 25
Dependent Claim
35 words
The method as recited in claim 19, wherein the substrate means comprises an optical anti-reflective substrate and wherein said absorber and tin material is vapor-deposited thereon only until a prescribed low-level virginal reflectance first appears.
Claim 26
Dependent Claim
21 words
The invention as recited in claim 20, wherein the tin strike is followed by a like antimony strike in insular form.
Claim 27
Independent Claim
210 words
A method of providing a recording blank for use over relatively long archival life with a low-power recording radiation source, this source providing a write beam at a given wavelength and relatively low write-energy, the method comprising: providing a polymeric substrate having a recording portion exhibiting prescribed optical and thermal characteristics at the given wavelength; applying a light strike of tin to the substrate in prescribed insular form; applying a prescribed information coating of gold or a gold alloy in insular form on the tin, on said portion of said substrate, this material exhibiting a prescribed absorptivity and as-deposited "virgin- reflectance" at the given wavelength, while also being adapted to be shifted to a prescribed "read-out reflectance" on reception of a writing pulse at said write-energy, this corresponding to information to be recorded on prescribed "bit-sites" on the coating; the tin and gold coatings being deposited as one or more ultra-thin discontinuous island layers formed into separated island globs so dimensioned and so separated as to exhibit a prescribed virgin- reflectance, while also being adapted to "agglomerate" upon application of said write-energy .pulse and to thus shift in reflectance to said read-out reflectance level, and thereby afford good detected read-out contrast by comparison with the non-recorded areas exhibiting said virginal-reflectance.
Claim 28
Independent Claim
210 words
A method of providing a recording blank for use over relatively long archival life with a low-power recording radiation source, this source providing a write beam at a given wavelength and relatively low write-energy, the method comprising: providing a polymeric substrate having a recording portion exhibiting prescribed optical and thermal characteristics at the given wavelength; applying a light strike of tin to the substrate in prescribed insular form; applying a prescribed information coating of gold or a gold alloy in insular form on the tin, on said portion of said substrate, this material exhibiting a prescribed absorptivity and as-deposited "virgin- reflectance" at the given wavelength, while also being adapted to be shifted to a prescribed "read-out reflectance" on reception of a writing pulse at said write-energy, this corresponding to information to be recorded on prescribed "bit-sites" on the coating; the tin and gold coatings being deposited as one or more ultra-thin discontinuous island layers formed into separated island globs so dimensioned and so separated as to exhibit a prescribed virgin- reflectance, while also being adapted to "agglomerate" upon application of said write-energy .pulse and to thus shift in reflectance to said read-out reflectance level, and thereby afford good detected read-out contrast by comparison with the non-recorded areas exhibiting said virginal-reflectance.
Claim 29
Dependent Claim
49 words
The method of claim 22, wherein the substrate is made anti-reflective and where said gold or gold alloy islands are vapor-deposited to a depth just sufficient to render a "first minimum reflectance" as the virginal reflectance, being adapted to so agglomerate as to form relatively fewer, further- separated "islands".
Claim 30
Dependent Claim
30 words
The method as recited in claim 23, wherein the substrate includes a polytetrafluorene spacer and subjecten reflector surface, those being adapted to form a "tri-layer" with the superposed metal island-layers.
Claim 31
Dependent Claim
31 words
The invention as recited in claim 24 wherein the insular tin strike is followed by a like insular strike of antimony on which the gold or gold alloy islands are deposited.
References Cited (Backward Citations)
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