US5146438A
Expired / Lapsed
US
⏱️ 0.0 years remaining
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 21:56
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.
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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) | 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 |