US4811331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Medium for recording digital information using an array of equally spaced micromirrors
Assignee: MICROMIRROR Corp A CO CORP
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Filing: 1987-08-20
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Granted: 1989-03-07
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Expires: 2007-08-20
Abstract
Abstract A digital recording medium formed of a thermoplastic substrate having an array of parallel rows of equally-spaced microscopic optically-alterable mirrors each supported by a mesa projecting from one surface. A layer of transparent plastic over the mirrors provides dust protection. The medium can be formed also from a single transparent thermoplastic substrate with an array of indentations in a first surface. The bottom of each indentation is coated with a reflective material. When viewed from the opposite surface of the substrate, the indentations become mesas. The micromirrors are formed of a composite of gold and silicon dioxide. Recording is by exposure to a laser beam that reduces the reflectivity of selected mirrors. After exposure to the recording laser beam, the mirrors retain enough reflectivity to be distinguishable from the intervening valleys. The mirrors serve as timing and tracking markers prior to and during recording, and during read-out. The area and location of each information bit is determined prior to recording: not as a result of the recording process. Scanning may be accomplished by reciprocating movement of the medium.
Inventors
- 👤 Arthur M. Gerber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:55
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B7/004; G11B7/0045; G11B7/00455; G11B7/007; G11B7/013; G11B7/08; G11B7/09; G11B7/2407; G11B7/24085
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
120 words
A medium for recording digital information comprising a substrate having an array of rows of discrete micromirrors, said rows being equally spaced from each other and said micromirrors being equally spaced within said rows, substantially all of said micromirrors in the unaltered state having a reflectivity of at least 20% and being individually capable of immediately detectable reduction in reflectivity by exposure to a single pulse of focused energy of less than 200 nanojoules per square micrometer thereby to become a depository for at least one bit of digital information, the specific area and position of each of said micromirrors subject to reduction in reflectivity by said focused energy being pre-defined individually identifiable prior to the exposure to such energy.
Claim 2
Independent Claim
120 words
A medium for recording digital information comprising a substrate having an array of rows of discrete micromirrors, said rows being equally spaced from each other and said micromirrors being equally spaced within said rows, substantially all of said micromirrors in the unaltered state having a reflectivity of at least 20% and being individually capable of immediately detectable reduction in reflectivity by exposure to a single pulse of focused energy of less than 200 nanojoules per square micrometer thereby to become a depository for at least one bit of digital information, the specific area and position of each of said micromirrors subject to reduction in reflectivity by said focused energy being pre-defined individually identifiable prior to the exposure to such energy.
Claim 3
Dependent Claim
45 words
The medium as claimed in claim 1 wherein said substrate if formed of transparent material having therein an array of depressions of uniform depth extending inwardly from one surface thereof, and each of said micromirrors is positioned at the bottom of one of said depressions.
Claim 4
Dependent Claim
28 words
The medium as claimed in claim 1 wherein said rows of micromirrors are equally spaced by a distance equal to the distance between adjacent micromirrors in said rows.
Claim 5
Dependent Claim
26 words
The medium as claimed in claim 1 wherein the minimum distance between said micromirrors is not significantly less than the maximum surface dimension of said micromirrors.
Claim 6
Dependent Claim
22 words
The medium as claimed in claim 1 wherein each of said micromirrors has an area between about 0.7 and four square micrometers.
Claim 7
Dependent Claim
40 words
The medium as claimed in claim 1 wherein said substrate comprises a flexible thermoplastic and including a plurality of mesas formed integrally with said substrate and each supporting one of said micromirrors, said mesas defining a plurality of valleys therebetween.
Claim 8
Dependent Claim
18 words
The medium as claimed in claim 1 wherein each of said micromirrors is formed of a metal-containing film.
Claim 9
Dependent Claim
19 words
The medium as claimed in claim 7 wherein said film is a composite of a metal and a silicate.
Claim 10
Dependent Claim
18 words
The medium as claimed in claim 8 wherein said film is a composite of gold and silicon dioxide.
Claim 11
Dependent Claim
37 words
The medium as claimed in claim 1 including a plurality of spaced discrete mesas extending from said reference surface, each supporting one of said micromirrors, and wherein each of said micromirrors is formed of a metal-containing film.
Claim 12
Dependent Claim
28 words
The medium as claimed in claim 6 wherein the reflectivity of said micromirrors in both the altered and unaltered state is greater than the reflectivity from the valleys.
Claim 13
Dependent Claim
22 words
The medium as claimed in claim 10 wherein each of said micromirrors has an area no greater than about five square micrometers.
Claim 14
Dependent Claim
90 words
A digital recording medium comprising a transparent thermoplastic substrate having first and second opposing surfaces, said first surface having therein a plurality of rows of equally spaced depressions, a plurality of optically-alterable micromirrors each formed on the bottom of one of said depressions, each of said micromirrors having a reflectivity of at least 20 percent of laser light focused upon it through said second surface of said substrate, wherein each of said micromirrors having its reflectivity reduced significantly by a laser beam having an energy level less than 200 nanojoules.
Claim 15
Dependent Claim
90 words
A digital recording medium comprising a transparent thermoplastic substrate having first and second opposing surfaces, said first surface having therein a plurality of rows of equally spaced depressions, a plurality of optically-alterable micromirrors each formed on the bottom of one of said depressions, each of said micromirrors having a reflectivity of at least 20 percent of laser light focused upon it through said second surface of said substrate, wherein each of said micromirrors having its reflectivity reduced significantly by a laser beam having an energy level less than 200 nanojoules.
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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) | 1992-03-06 | 1992-09-05 | 1993-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-06 | 1996-09-05 | 1997-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-06 | 2000-09-05 | 2001-03-07 | $7700.00 | Window Closed / Lapsed |