US5420834A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical disk recorders using disks coatings close to outer surfaces with optical path extending through a thick transparent substrate
Assignee: International Business Machines Corp
•
Filing: 1994-05-24
•
Granted: 1995-05-30
•
Expires: 2014-05-24
Abstract
Abstract A magnetooptical disk has two axially space-apart translucent recording layers. Each translucent recording layer is axially closer to an outer surface of the disk than to the other recording layer. This geometry enables closely axially disposing a magnetic field biasing means to each of the recording layers from opposite axial sides of the disk, respectively. Laser beams are axially introduced into the disk to pass through one of the translucent recording layers in a defocussed state to reach a second recording layer in a focussed state. In this manner, recording in the second layer is effected by a modulated magnetic bias field using a constant intensity laser beam. Two sets of laser beams and magnetic biasing means are provided for recording on both data in both of the recording layers.
Inventors
- 👤 Blair I. Finkelstein
- 👤 Andrew A. Gaudet
- 👤 Terry W. McDaniel
- 👤 Hal J. Rosen
- 👤 Kurt A. Rubin
- 👤 Timothy C. Strand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:59
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10504; G11B11/10508; G11B11/1055; G11B11/10552; G11B11/10582; G11B11/10584; G11B11/10595; G11B11/10597; G11B13/00; G11B13/04; G11B13/045; G11B7/00; G11B2007/0003; G11B2007/0009; G11B2007/0013; G11B7/24; G11B7/2403; G11B7/24035; G11B7/24038
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
294 words
An optical disk recording/playing device having means for rotatably supporting an optical disk in a play position, the improvement including, in combination: the optical disk having a transparent annular planar substrate having a predetermined axial dimension and first and second oppositely facing surfaces; first and second axially spaced-apart translucent annular planar optically responsive recording layers respectively on said first and second oppositely facing surfaces; first and second transparent coatings respectively disposed on and covering said first and second recording layers, said first and second transparent coatings having respective axial thicknesses of an order of magnitude thinner than said predetermined axial dimension, said first and second transparent coatings respectively having first and second outwardly facing annular surfaces such that the axial spacing between said first and second recording layers is greater than the axial spacings respectively between said first and second annular surfaces and said first and second recording layers; first optical means in the device having means for supplying a laser beam to be focussed on said second recording layer through said first annular surface along a first predetermined axial path including a portion of the path being in said substrate such that said laser beam is in focus on said second recording layer and passing through the first coating and said first recording layer in a defocussed state; and first magnetic bias field means in the device disposed axially adjacent said second annular surface of the disk and being circumferentially aligned with said first predetermined path for supplying a bias magnetic field to said second recording layer simultaneously with said first optical means supplying said laser beam focussed on said second recording layer whereby signals are recorded on said second recording layer using a constant laser beam intensity and a signal-modulated magnetic field.
Claim 2
Dependent Claim
294 words
An optical disk recording/playing device having means for rotatably supporting an optical disk in a play position, the improvement including, in combination: the optical disk having a transparent annular planar substrate having a predetermined axial dimension and first and second oppositely facing surfaces; first and second axially spaced-apart translucent annular planar optically responsive recording layers respectively on said first and second oppositely facing surfaces; first and second transparent coatings respectively disposed on and covering said first and second recording layers, said first and second transparent coatings having respective axial thicknesses of an order of magnitude thinner than said predetermined axial dimension, said first and second transparent coatings respectively having first and second outwardly facing annular surfaces such that the axial spacing between said first and second recording layers is greater than the axial spacings respectively between said first and second annular surfaces and said first and second recording layers; first optical means in the device having means for supplying a laser beam to be focussed on said second recording layer through said first annular surface along a first predetermined axial path including a portion of the path being in said substrate such that said laser beam is in focus on said second recording layer and passing through the first coating and said first recording layer in a defocussed state; and first magnetic bias field means in the device disposed axially adjacent said second annular surface of the disk and being circumferentially aligned with said first predetermined path for supplying a bias magnetic field to said second recording layer simultaneously with said first optical means supplying said laser beam focussed on said second recording layer whereby signals are recorded on said second recording layer using a constant laser beam intensity and a signal-modulated magnetic field.
Claim 3
Dependent Claim
191 words
The device set forth in claim 1, further including, in combination: second optical means in the device having means for supplying a laser beam via an objective lens in a defocussed state through said second annular surface along a second predetermined axial path for focussing said laser beam on said first recording layer, said second predetermined axial path including a portion in said transparent substrate, said second axial path being circumferentially displaced from said first axial path; second magnetic bias field means in the device disposed axially adjacent said first annular surface of the disk and being circumferentially aligned with said second predetermined path for supplying a bias magnetic field to said first recording layer; and control means connected to said first optical means and to said first magnetic bias field means for simultaneously actuating said first optical means and said first magnetic bias field means for recording data on said second recording layer and being connected to said second optical means and to second magnetic bias field means for simultaneously actuating said second optical means and said second magnetic bias field means for recording data on said first recording layer.
Claim 4
Dependent Claim
60 words
The device set forth in claim 2, further including, in combination: said first and second recording layers including a predetermined portion consisting of a selected one from a group of recording layer portions comprising a read-only recording layer portion, a phase-change recording layer portion, a photochromic recording layer portion, a magnetooptical recording layer portion or a write-once recording layer portion.
Claim 5
Dependent Claim
65 words
The device set forth in claim 2, further including, in combination: said control means having data means connected to said first and second magnetic bias field means for supplying data indicating signals to said first and second magnetic bias field means for respectively modulating magnetic bias fields respectively supplied by said first and second magnetic bias field means to said second and first recording layers.
Claim 6
Dependent Claim
62 words
The device set forth in claim 1, further including, in combination: said recording layers including a recording layer having a predetermined portion selected from a group of recording layer portions comprising a read-only recording layer portion, a photochromic recording layer portion, a phase-change recording layer portion, a photochromic recording layer portion, a magnetooptical recording layer portion or a write-once recording layer portion.
Claim 7
Dependent Claim
41 words
The device set forth in claim 1, further including, in combination; each said translucent recording layers having an axial thickness of not greater than 200 Angstrom units. magnetooptical material having an axial thickness of not greater than about 200 Angstrom units.
Claim 8
Dependent Claim
153 words
In a method of recording data signals on a recording layer of an optical disk having first and second axially spaced-apart optically-translucent recording layers respectively disposed axially immediately adjacent first and second surfaces of the disk, a transparent substrate axially interposed between said recording layers for supporting said recording layers in an axially spaced-apart relationship; including steps of: shining a first laser beam along a predetermined axially extending path into the optical disk through the first surface of the disk for first axially traversing said first recording layer in a defocussed state for not heating the first layer axial traversed to a temperature at which recording occurs, then impinging said first laser beam, via said transparent substrate, on said second recording layer in a focussed state for heating the point of impingement of said laser beam on the second recording layer to a temperature at which recording occurs in said second recording layer.
Claim 9
Dependent Claim
153 words
In a method of recording data signals on a recording layer of an optical disk having first and second axially spaced-apart optically-translucent recording layers respectively disposed axially immediately adjacent first and second surfaces of the disk, a transparent substrate axially interposed between said recording layers for supporting said recording layers in an axially spaced-apart relationship; including steps of: shining a first laser beam along a predetermined axially extending path into the optical disk through the first surface of the disk for first axially traversing said first recording layer in a defocussed state for not heating the first layer axial traversed to a temperature at which recording occurs, then impinging said first laser beam, via said transparent substrate, on said second recording layer in a focussed state for heating the point of impingement of said laser beam on the second recording layer to a temperature at which recording occurs in said second recording layer.
Claim 10
Dependent Claim
60 words
The method set forth in claim 7, further including the steps of: supplying a second laser beam circumferentially displaced from said first laser beam, axially through said second annular surface in a defocussed state to impinge on said first recording layer, after passing through said transparent substrate, in a focussed state for recording predetermined data on said first recording layer.
Claim 11
Dependent Claim
62 words
The method set forth in claim 8, further including the steps of: selecting said recording layer to include a recording layer portion selected from a group of recording layer portions comprising a read-only recording layer portion, a photochromic recording layer portion, a phase-change recording layer portion, a photochromic recording layer portion, a magnetooptical recording layer portion or a write-once recording layer portion.
Claim 12
Dependent Claim
72 words
The method set forth in claim 7, further including the steps of: selecting at least a portion of one of said recording layers to consist of magnetooptical material; and magnetically axially imposing a bias magnetic field on said portion through said outer surface of the disk axially closest to the portion to be coincident with impingement of said focussed laser beam on said portion for magnetooptically recording data signals in said portion.
Claim 13
Independent Claim
158 words
The method of recording data into an optical disk having a transparent annular substrate having first and second outwardly facing annular surfaces and having a predetermined axial thickness sufficient for enabling a defocussed laser beam entering one of said surfaces to be in a focussed state at an opposite one of said surfaces, an annular magnetooptical recording layer disposed on said second annular surface, a coating disposed on said recording layer having a thickness an order of magnitude less than the axial thickness of said transparent substrate; including steps of: shining a laser beam axially into said optical disk passing first through said first surface in a defocussed state and reaching said recording layer in a focussed state; and simultaneously to shining said laser beam, imposing a magnetic bias field through said coating and circumferentially aligned with said laser beam onto said recording layer including modulating the imposed magnetic bias field for recording data in said recording layer.
Claim 14
Independent Claim
158 words
The method of recording data into an optical disk having a transparent annular substrate having first and second outwardly facing annular surfaces and having a predetermined axial thickness sufficient for enabling a defocussed laser beam entering one of said surfaces to be in a focussed state at an opposite one of said surfaces, an annular magnetooptical recording layer disposed on said second annular surface, a coating disposed on said recording layer having a thickness an order of magnitude less than the axial thickness of said transparent substrate; including steps of: shining a laser beam axially into said optical disk passing first through said first surface in a defocussed state and reaching said recording layer in a focussed state; and simultaneously to shining said laser beam, imposing a magnetic bias field through said coating and circumferentially aligned with said laser beam onto said recording layer including modulating the imposed magnetic bias field for recording data in said recording layer.
Claim 15
Dependent Claim
32 words
In the method set forth in claim 11, including a step of: selecting said recording layer to comprise magnetooptical material having an axial thickness of not greater than about 200 Angstrom units.
Claim 16
Dependent Claim
25 words
In the method set forth in claim 11, including a step of: selecting said coating to have an axial thickness of about 1200 Angstrom units.
Claim 17
Dependent Claim
28 words
In the apparatus set forth in claim 1, further including, in combination: said first and second transparent coatings each having an axial thickness of about 1200 Angstrom units.
References Cited (Backward Citations)
GB2017379A
Cited
US4737947A
Cited
US4740947A
Cited
US4807204A
Cited
EP0424809A2
Cited
EP0517490A2
Cited
US5202880A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-05-29 | 1998-11-28 | 1999-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-05-29 | 2002-11-28 | 2003-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-05-29 | 2006-11-28 | 2007-05-30 | $7700.00 | Window Closed / Lapsed |