Patent US4807218A successfully refreshed from Google Patents.
US4807218A
Expired / Lapsed
US
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System for recording digital information using a regular array of discrete micromirrors
Assignee: MICROMIRROR Corp A CO CORP
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Filing: 1987-08-27
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Granted: 1989-02-21
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Expires: 2007-08-27
Abstract
Abstract A digital recording medium formed of a thermoplastic substrate having a regular array of microscopic optically-alterable mirrors each by a mesa projecting from one surface. The parallel rows of the mirrors are the same distance apart as the mirrors in each row. A layer of transparent plastic over the mirrors provides dust protection. The medium can be formed 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. 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. The mirrors are scanned diagonally across the rows that make up the array. Scanning is accomplished by reciprocating movement of the medium.
Inventors
- 👤 Arthur M. Gerber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:45
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: 16
Claim 1
Independent Claim
128 words
A system for recording digital information comprising a laser beam source, a recording medium having a substrate, and an array of equally spaced, discrete, immediately detectable alterable micromirrors arranged in equally spaced parallel rows, each of said micromirrors having in its unaltered state a reflectivity of at least twenty percent of the laser beam produced by said source, and being capable of recording at least one bit of digital information, said laser beam source being capable of sufficient intensity to immediately reduce the reflectivity of a micromirror of said medium exposed to said beam, scanning means arranged to focus said laser beam successively on and identify individual micromirrors of said medium, and modulation means arranged to modulate said beam in accordance with the digital information to be recorded.
Claim 2
Independent Claim
128 words
A system for recording digital information comprising a laser beam source, a recording medium having a substrate, and an array of equally spaced, discrete, immediately detectable alterable micromirrors arranged in equally spaced parallel rows, each of said micromirrors having in its unaltered state a reflectivity of at least twenty percent of the laser beam produced by said source, and being capable of recording at least one bit of digital information, said laser beam source being capable of sufficient intensity to immediately reduce the reflectivity of a micromirror of said medium exposed to said beam, scanning means arranged to focus said laser beam successively on and identify individual micromirrors of said medium, and modulation means arranged to modulate said beam in accordance with the digital information to be recorded.
Claim 3
Dependent Claim
111 words
The system as claimed in claim 1 wherein said scanning means is arranged to focus said beam successively on the individual micromirrors, and said modulation means is arranged to change the intensity of said beam between two levels of intensity in accordance with the information to be recorded, one of said levels being of sufficient intensity to produce an immediately detectable reduction in the reflectivity of one of said micromirrors as a result of exposure to said scanning beam, and the other of said levels being of an intensity that causes no significant reduction in the refelectivity of a micromirror as a result of exposure to said laser beam during scanning.
Claim 4
Dependent Claim
16 words
The system as claimed in claim 1 wherein said laser beam source is a diode laser.
Claim 5
Dependent Claim
14 words
The system as claimed in claim 1 wherein each of said micromirrors is flat.
Claim 6
Dependent Claim
34 words
the system as claimed in claim 1 wherein each of said micromirrors is supported by thermoplastic material and in which said reduction in reflectivity is the result of heat deformation of siad thermoplastic material.
Claim 7
Dependent Claim
29 words
The system as claimed in claim 5 including a plurality of spaced, discrete projections extending from one surface of said thermoplastic material and each supporting one of said micromirrors.
Claim 8
Dependent Claim
23 words
The system as claimed in claim 5 wherein each of said micromirors has a maximum surface dimension between about one and 2.5 micrometers.
Claim 9
Dependent Claim
16 words
The system as claimed in claim 5 wherein each of said micromirrors comprises a metal-containing film.
Claim 10
Dependent Claim
73 words
The system as claimed in claim 6 wherein said medium comprises a sheet of plastic having formed integrally therewith an array of parallel rows of discrete mesas equally spaced in said rows and each supporting one of said micromirrors, each of said micromirrors being capable of being destroyed by a single pulse of focused energy less than 200 nanojoules per square micrometer thereby to form a depository for one bit of digital information.
Claim 11
Dependent Claim
61 words
The system as claimed in claim 6 wherein in the unaltered state each of said micromirrors has a reflectivity between 20 and 55 percent, and in an altered state has a reflectivity substantially less than in the unaltered state, the number and location of said micromirrors having areduced reflectivity that is a function of the digital information recorded on said medium.
Claim 12
Dependent Claim
24 words
The system as claimed in claim 5 wherein said scanning means is arranged to scan said rows along parallel paths diagonal to said rows.
Claim 13
Dependent Claim
22 words
A system as claimed in claim 11 wherein said scanning means is arranged to scan along said paths successively in opposite directions.
Claim 14
Dependent Claim
35 words
The system as claimed in claim 11 wherein each of said micromirrors is a metal-containing film having a reflectivity of at least 20 percent and a maximum surface dimension between about one and 2.5 micrometers.
Claim 15
Dependent Claim
37 words
The system as claimed in claim 13 wherein said substrate has a reference surface and an array of parallel rows of mesas equally spaced within said rows extending from said surface, each supporting one of said micromirrors.
Claim 16
Dependent Claim
14 words
The system as claimed in claim 14 including a transparent layer overlying said micromirrors.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |