Patent US5146438A successfully refreshed from Google Patents.
US5146438A
Expired / Lapsed
US
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Method of making double-sided magneto-optical disks having reduced birefringence
Assignee: Philips and Du Pont Optical Co
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Filing: 1990-05-30
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Granted: 1992-09-08
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Expires: 2010-05-30
Abstract
Abstract The invention is directed to a two-sided magneto-optical recording disk having reduced birefringence comprising a pair of single-sided magneto-optical recording disks, the entire recording sides of which are adhered together by means of a continuous layer of polymeric adhesive. An external mechanical laminating pressure in a vacuum is applied to the non-information areas of the a magneto-optical disk.
Inventors
- 👤 Fred J. Harper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:37
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; B; B29; B29C; B29C65/00; B29C65/48; B29C65/50; B29C65/78; B29C65/7802; B29C65/7805; B29C65/7808; B29C65/7811; B29C66/00; B29C66/01; B29C66/05; B29C66/10; B29C66/11; B29C66/112; B29C66/1122; B29C66/40; B29C66/41; B29C66/45; B29C66/452; B29C66/80; B29C66/82; B29C66/826; B29C66/8266; B29C66/82661; B29C66/83; B29C66/832; B29C66/8322; B29C65/4805; B29C65/481; B29C65/4815; B29C65/4825; B29C66/70; B29C66/71; B29K; B29K2995/00; B29K2995/0018; B29K2995/0031; B29K2995/0032; B29L; B29L2017/00; B29L2017/001; B29L2017/003; B29L2017/005
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
141 words
A method for making two-sided magneto-optic recording disks having reduced birefringence comprising the sequential steps of (a) forming two single-sided magneto-optical recording disks each comprising a flat dimensionally stable transparent substrate having a center hole, a recording side of which contains a central non-information area annular to the center hole, an intermediate information area coated with a magnetic recording material adjacent to the central non-information area, and a peripheral non-information area adjacent to the information area; (b) applying a continuous layer of compliant adhesive evenly across the surface of the recording side of both optical recording disks; and (c) laminating the adhesive-coated surfaces of both single-side disks to each other in a vacuum with the application of external mechanical pressure of 0.03-0.7 kg/cm 2 only to the non-information areas, thus forming an adhesive barrier between the recording sides of both disks.
Claim 2
Independent Claim
141 words
A method for making two-sided magneto-optic recording disks having reduced birefringence comprising the sequential steps of (a) forming two single-sided magneto-optical recording disks each comprising a flat dimensionally stable transparent substrate having a center hole, a recording side of which contains a central non-information area annular to the center hole, an intermediate information area coated with a magnetic recording material adjacent to the central non-information area, and a peripheral non-information area adjacent to the information area; (b) applying a continuous layer of compliant adhesive evenly across the surface of the recording side of both optical recording disks; and (c) laminating the adhesive-coated surfaces of both single-side disks to each other in a vacuum with the application of external mechanical pressure of 0.03-0.7 kg/cm 2 only to the non-information areas, thus forming an adhesive barrier between the recording sides of both disks.
Claim 3
Dependent Claim
28 words
The method of claim 1 in which the adhesive layer is in the form of a two-sided pressure-sensitive adhesive tape inserted between the recording side of the disks.
Claim 4
Dependent Claim
16 words
The method of claim 1 in which an adhesive layer is applied separately to both disks.
Claim 5
Dependent Claim
17 words
The method of claim 1 in which the recording side of the disks has a protective coating.
Claim 6
Dependent Claim
17 words
The method of claim 1 in which the non-recording side of the disk has a protective coating.
Claim 7
Dependent Claim
13 words
The method of claim 1 wherein the adhesive is a hot melt adhesive.
Claim 8
Dependent Claim
96 words
A two-sided magneto-optic recording disk having reduced birefringence comprising a pair of single-sided magneto-optic recording disks each comprising a flat dimensionally stable transparent substrate having a center hole, a recording side of which contains a central non-information area, an intermediate information area coated with magnetic recording material and a peripheral non-information area, the entire recording side of the single-sided recording disks being adhered together by means of a continuous layer of polymeric adhesive applied by the imposition of mechanical laminating pressure in a vacuum of 0.03-0.7 kg/cm 2 only upon the non-information areas of the disks.
Claim 9
Dependent Claim
96 words
A two-sided magneto-optic recording disk having reduced birefringence comprising a pair of single-sided magneto-optic recording disks each comprising a flat dimensionally stable transparent substrate having a center hole, a recording side of which contains a central non-information area, an intermediate information area coated with magnetic recording material and a peripheral non-information area, the entire recording side of the single-sided recording disks being adhered together by means of a continuous layer of polymeric adhesive applied by the imposition of mechanical laminating pressure in a vacuum of 0.03-0.7 kg/cm 2 only upon the non-information areas of the disks.
References Cited (Backward Citations)
US4432002A
Cited
US4449138A
Cited
US4740947A
Cited
US4911968A
Cited
US4954379A
Cited
US4731620A
Cited
US4892606A
Cited
US4909871A
Cited
US4834819A
Cited
US4847827A
Cited
US4939011A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-08 | 1996-03-09 | 1996-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-08 | 2000-03-09 | 2000-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-08 | 2004-03-09 | 2004-09-08 | $7700.00 | Window Closed / Lapsed |