US5784352A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for accessing data on multilayered optical media
Assignee: Massachusetts Institute of Technology
•
Filing: 1997-08-19
•
Granted: 1998-07-21
•
Expires: 2017-08-19
Abstract
Abstract Apparatus and methods for accessing data on a multilayered optical storage medium. The apparatus uses the time-of-flight of illumination directed to and reflected by the layers of the optical medium to access data stored on a desired layer of the medium. More particularly, alterations in illumination reflected from the desired layer are detected to access data stored on the layer. In accordance with embodiments of the invention utilizing interferometric techniques, the time-of-flight of a reference illumination is adjusted to cause interference of the reference illumination with the illumination reflected from the layer which contains the data to be accessed. Alternatively, and in accordance with embodiments of the invention utilizing non-interferometric techniques, the time-of-flight of illumination reflected by the layer which contains the data to be accessed is selected to permit data stored on the desired layer to be accessed.
Inventors
- 👤 Eric A. Swanson
- 👤 Stephen R. Chinn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:22
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/0065; A; A61; A61B; A61B5/00; A61B5/0059; A61B5/0062; A61B5/0066; B; B82; B82Y; B82Y15/00; G01; G01B; G01B11/00; G01B11/24; G01B11/2441; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/4795; G02; G02B; G02B27/00; G02B27/42; G02B27/4233; G02B27/4238; G02B5/00; G02B5/18; G02B5/1828; G11B7/002; G11B7/0037; G11B7/005; G11B7/08; G11B7/085; G11B7/08547; G11B7/08564; G11B7/09; G11B7/0908; G11B7/12; G11B7/125; G11B7/126; G11B7/128; G11B7/135; G11B7/1353; G11B7/14; G11B7/24; A61B5/44; A61B5/441; G11B2007/0003; G11B2007/0009; G11B2007/0013; G11B7/0945; H; H01; H01S; H01S5/00; H01S5/10; H01S5/14; H01S5/141
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
55 words
A system for reading data comprising: a medium containing said data, said data disposed on at least one layer; a source of illumination, said illumination incident upon said medium; and a time-of-flight device for selecting said at least one layer and measuring alteration of said incident illumination caused by data on at least one layer.
Claim 2
Independent Claim
55 words
A system for reading data comprising: a medium containing said data, said data disposed on at least one layer; a source of illumination, said illumination incident upon said medium; and a time-of-flight device for selecting said at least one layer and measuring alteration of said incident illumination caused by data on at least one layer.
Claim 3
Dependent Claim
13 words
The system of claim 1 wherein said time-of-flight detector is an interferometric detector.
Claim 4
Independent Claim
13 words
The system of claims 2 wherein said interferometric detector is a Michelson interferometer.
Claim 5
Independent Claim
19 words
The system of claims 2 wherein said interferometric detector is a Michelson interferometer with a variable reference path length.
Claim 6
Dependent Claim
15 words
The method of claim 2 wherein said source of illumination is a constant envelope source.
Claim 7
Dependent Claim
18 words
The system of claim 5 wherein said source of illumination is a continuous wave short coherence length source.
Claim 8
Dependent Claim
18 words
The system of claim 5 wherein said source of illumination has a frequency chirp on an optical carrier.
Claim 9
Dependent Claim
23 words
The system of claim 7 wherein said at least one predetermined layer is selected by modulating said frequency chirp on said optical carrier.
Claim 10
Dependent Claim
13 words
The system of claim 2 wherein said illumination is an intensity modulated source.
Claim 11
Dependent Claim
14 words
The system of claim 9 wherein said source of illumination is a pulsed source.
Claim 12
Dependent Claim
39 words
The system of claim 2 wherein said interferometric detector includes a frequency shifter which modulates a carrier frequency of light in one arm of said interferometric detector with respect to light in a second arm of said interferometric detector.
Claim 13
Dependent Claim
25 words
The system of claim 2 wherein said interferometer further includes a movable mirror, said mirror being movable to select said at least one predetermined layer.
Claim 14
Dependent Claim
13 words
The system of claim 1 wherein said time-of-flight detector is a non-interferometric detector.
Claim 15
Dependent Claim
15 words
The system of claim 13 wherein said non-interferometric detector is an optical time delay detector.
Claim 16
Dependent Claim
22 words
The system of claim 13 wherein said non-interferometric detector correlates the frequency of detected intensity from said data with a reference signal.
Claim 17
Dependent Claim
15 words
The system of claim 13 wherein said source of illumination is an intensity modulated source.
Claim 18
Dependent Claim
14 words
The system of claim 16 wherein said source of illumination is a pulsed source.
Claim 19
Dependent Claim
21 words
The system of claim 16 wherein said source of illumination is an intensity modulated illumination source whose modulation is frequency chirped.
Claim 20
Dependent Claim
24 words
The system of claim 1 wherein said measurement of said alteration of said incident illumination is performed on a plurality of predetermined layers simultaneously.
Claim 21
Dependent Claim
37 words
The system of claim 1 wherein said system further comprises a plurality of time-of-flight detectors and said measurement of said alteration of said incident illumination is performed on a plurality of locations on said predetermined layer simultaneously.
Claim 22
Dependent Claim
22 words
The system of claim 1 wherein said alteration of said incident illumination is selected from the group consisting of reflectivity and polarization.
Claim 23
Dependent Claim
27 words
The system of claim 1 wherein said alteration of said incident illumination has a plurality of discrete values arising from a single spatial location of said layer.
Claim 24
Dependent Claim
16 words
The system of claim 1 wherein said time-of-flight device is a Mirau interference objective lens unit.
Claim 25
Dependent Claim
23 words
The system of claim 1 wherein said medium comprises a plurality of layers and said data is disposed on said plurality of layers.
Claim 26
Dependent Claim
26 words
The system of claim 1 wherein said medium is a unitary structure and said data is disposed in a plurality of layers within said unitary medium.
Claim 27
Independent Claim
66 words
A method of accessing data comprising the steps of: illuminating, with incident light, a medium containing data, said data being disposed on at least one layer; selecting said at least one layer in accordance with time-of-flight of said light to and from said medium; and detecting said data from at least one layer by detection of alteration of said incident light as altered by said data.
Claim 28
Independent Claim
66 words
A method of accessing data comprising the steps of: illuminating, with incident light, a medium containing data, said data being disposed on at least one layer; selecting said at least one layer in accordance with time-of-flight of said light to and from said medium; and detecting said data from at least one layer by detection of alteration of said incident light as altered by said data.
Claim 29
Dependent Claim
11 words
The method of claim 26 wherein said detection is performed interferometrically.
Claim 30
Dependent Claim
14 words
The method of claim 27 wherein said detection is performed with a Michelson interferometer.
Claim 31
Dependent Claim
20 words
The method of claim 27 wherein said detection is performed with a Michelson interferometer with a variable reference path length.
Claim 32
Dependent Claim
15 words
The method of claim 27 wherein said illumination is performed using a constant envelope source.
Claim 33
Dependent Claim
18 words
The method of claim 30 wherein said constant envelope source is a continuous wave short coherence length source.
Claim 34
Dependent Claim
16 words
The method of claim 30 wherein said illumination has a frequency chirp on an optical carrier.
Claim 35
Dependent Claim
17 words
The method of claim 27 wherein said illumination is performed by pulsing the intensity of said source.
Claim 36
Dependent Claim
30 words
The method of claim 27 further comprising the step of frequency shifting light in one arm of an interferometric detector with respect to a second arm of said interferometric detector.
Claim 37
Dependent Claim
23 words
The method of claim 27 further comprising the step of moving a mirror in an interferometer to select said at least one layer.
Claim 38
Dependent Claim
11 words
The method of claim 26 wherein said detection is performed non-interferometrically.
Claim 39
Dependent Claim
15 words
The method of claim 36 wherein said detection is performed by optical time delay reflectometry.
Claim 40
Dependent Claim
21 words
The method of claim 36 wherein said detection is performed by frequency correlating the detected intensity of the altered incident illumination.
Claim 41
Dependent Claim
17 words
The method of claim 26 wherein said illumination is performed by intensity modulating a source of illumination.
Claim 42
Dependent Claim
15 words
The method of claim 39 wherein the intensity of said source of illumination is pulsed.
Claim 43
Dependent Claim
20 words
The method of claim 39 wherein said illumination is performed by frequency chirp of an intensity modulation of said source.
Claim 44
Dependent Claim
21 words
The method of claim 26 wherein said at least one layer is selected using a frequency chirp of an optical carrier.
Claim 45
Dependent Claim
17 words
The method of claim 26 wherein said detecting is performed on a plurality of predetermined layers simultaneously.
Claim 46
Dependent Claim
21 words
The method of claim 26 wherein said detecting is performed on a plurality of locations on a single predetermined layer simultaneously.
Claim 47
Dependent Claim
23 words
The method of claim 26 wherein said detected alteration of said incident light is selected from the group consisting of reflectivity and polarization.
Claim 48
Dependent Claim
26 words
The method of claim 26 wherein said alteration of said incident illumination has a plurality of discrete values arising from single spatial location of said layer.
Claim 49
Dependent Claim
23 words
The method of claim 26 wherein said medium comprises a plurality of layers and said data is disposed on said plurality of layers.
Claim 50
Dependent Claim
26 words
The method of claim 26 wherein said medium is a unitary structure and said data is disposed on a plurality of layers within said unitary medium.
Claim 51
Independent Claim
57 words
A system for accessing data comprising: a medium containing data disposed on at least one layer; a source of illumination, said illumination incident upon said medium; and an interferometric detector including an optical frequency shifter, said interferometric detector providing a reference path length corresponding to a predetermined layer on which said data is disposed to be accessed.
Claim 52
Independent Claim
57 words
A system for accessing data comprising: a medium containing data disposed on at least one layer; a source of illumination, said illumination incident upon said medium; and an interferometric detector including an optical frequency shifter, said interferometric detector providing a reference path length corresponding to a predetermined layer on which said data is disposed to be accessed.
Claim 53
Dependent Claim
35 words
The system of claim 49 wherein said interferometric detector further comprises a movable mirror in a reference arm, said mirror being movable to select said predetermined layer in said medium containing data to be accessed.
Claim 54
Dependent Claim
23 words
The system of claim 49 wherein said medium comprises a plurality of layers and said data is disposed on said plurality of layers.
Claim 55
Dependent Claim
22 words
The system of claim 49 wherein said medium is a unitary structure and said data is disposed on said plurality of layers.
Claim 56
Dependent Claim
47 words
A multilayered medium for use in a data accessing system using time-of-flight detection and focussing optics, said medium comprising a plurality of layers, wherein the minimum thickness of each of said plurality of layers requires the use of both time-of-flight and focussing optics to access said layers.
Claim 57
Dependent Claim
47 words
A multilayered medium for use in a data accessing system using time-of-flight detection and focussing optics, said medium comprising a plurality of layers, wherein the minimum thickness of each of said plurality of layers requires the use of both time-of-flight and focussing optics to access said layers.
Claim 58
Dependent Claim
33 words
The multilayered medium of claim 53 wherein the minimum thickness of each of said plurality of layers is less than the minimum thickness permitted by the point-spread function of the focussing optics alone.
References Cited (Backward Citations)
US3912391A
Cited
US3905703A
Cited
US4969142A
Cited
JPS61227237A
Cited
JPS61240447A
Cited
US5097464A
Cited
US5121376A
Cited
EP0446063A1
Cited
US5218594A
Cited
EP0511023A1
Cited
US5251198A
Cited
JPH0749306A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-07-20 | 2002-01-19 | 2002-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-07-20 | 2006-01-19 | 2006-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-07-20 | 2010-01-19 | 2010-07-21 | $7700.00 | Window Closed / Lapsed |