US4729805A
Expired / Lapsed
US
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Recording medium annealing process
Assignee: 3M Co
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Filing: 1986-08-11
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Granted: 1988-03-08
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Expires: 2006-08-11
Abstract
Abstract Stretched surface recording disk (SD) 10 comprises an annular support 12 having raised annular ridges 42 and 28 at its inside and outside diameters 22 and 30 with a base portion 24 in between the two ridges, and an annular recording medium film 14 held in radial tension and stretched across the base portion by adhering the film to attachment surfaces 48 and 36 near the inside and outside diameters respectively. The SD is annealed twice during manufacture to relieve stress in the stretched film 14. This annealing results in SD essentially free from track anisotropy and stress distribution anisotropy in the plane of the disk. As a result, data tracks are more stable than in previous SD, track density can be greater, and the SD is generally more reliable.
Inventors
- 👤 Jerry L. Alexander
- 👤 Sankar B. Narayan
- 👤 Sten R. Gerfast
- 👤 Charles E. Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:15
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/0014; G11B23/0021; G11B23/005; G11B5/00; G11B5/74; G11B5/82; G11B5/825; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/91
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
158 words
A process for annealing a stretched surface recording disk comprising a rigid annular support, having at least two concentric raised annular reference surfaces and an annular polymeric film, having a recording layer, attached to the support and stretched between and supported by the raised annular reference surfaces, said process comprising: A. annealing a polymeric film which has been fixed in radial tension, at a temperature above its glass transition temperature for a time sufficient to obtain a substantial absence of anisotropic stress distribution in the film; B. bonding the annealed film from step A to the annular support at or near the inside and outside diameters of the support; and C. annealing the product of step B, at a temperature above the glass transition temperature of the polymeric film but below the temperature which would cause warping of the annular support, for a time sufficient to obtain a substantial absence of anisotropic stress distribution in the polymeric film.
Claim 2
Dependent Claim
158 words
A process for annealing a stretched surface recording disk comprising a rigid annular support, having at least two concentric raised annular reference surfaces and an annular polymeric film, having a recording layer, attached to the support and stretched between and supported by the raised annular reference surfaces, said process comprising: A. annealing a polymeric film which has been fixed in radial tension, at a temperature above its glass transition temperature for a time sufficient to obtain a substantial absence of anisotropic stress distribution in the film; B. bonding the annealed film from step A to the annular support at or near the inside and outside diameters of the support; and C. annealing the product of step B, at a temperature above the glass transition temperature of the polymeric film but below the temperature which would cause warping of the annular support, for a time sufficient to obtain a substantial absence of anisotropic stress distribution in the polymeric film.
Claim 3
Dependent Claim
23 words
The process of claim 1 wherein step B is performed by bonding the annealed film to the annular support using a thermosetting adhesive.
Claim 4
Dependent Claim
53 words
The process of claim 1 wherein step B is performed by using an adhesive selected from the group consisting of acrylate and methacrylate functional adhesives which are curable by radiation, said adhesive being applied inbetween the polymeric film and the annular support, and curing said adhesive by exposing it to electron beam radiation.
Claim 5
Dependent Claim
31 words
The process of claim 3 wherein the adhesive is selected from the group consisting of acrylated epoxy resins, acrylated bisphenol A resins, polyester acrylate resins, acrylated urethane resina and alkyd acrylates.
Claim 6
Dependent Claim
44 words
The process of cIaim 3 wherein the electron beam irradiation process of step B is performed using an inert atmosphere having less than 60 ppm oxygen, and the annealed film and annular support are exposed to no more than about 10 Mrad of radiation.
Claim 7
Dependent Claim
44 words
The process of cIaim 3 wherein the electron beam irradiation process of step B is performed using an inert atmosphere having less than 60 ppm oxygen, and the annealed film and annular support are exposed to no more than about 10 Mrad of radiation.
Claim 8
Dependent Claim
30 words
The process of claim 1 wherein step A is carried out at conditions selected from: 16 hours of annealing at 66° C. or 3 minutes of annealing at 166° C.
Claim 9
Dependent Claim
30 words
The process of claim 1 wherein step C is carried out at conditions selected from: 4 mintues of annealing at 93° C. or 36 hours of anneling at 66° C.
Claim 10
Dependent Claim
201 words
A process for annealing a stretched surface recording disk comprising a rigid annular support, having at least two concentric raised annular reference surfaces and an annular polymeric film, having a recording layer, attached to the support and stretched between and supported by the raised annular reference surfaces, said process comprising: A. annealing a polymeric film which has been fixed in radial tension, at a temperature above its glass transition temperature for a time sufficient to obtain a substantial absence of anisotropic stree distribution in the film; B. bonding the annealed film from step A to the annular support at or near the inside and outside diameters of the support; and C. annealing the product of step B in an oven by placing the product of step B within a temperature dampening chamber within an oven, said temperature dampening chamber consisting essentially of a container larger than the annular support and a holding means for holding the product of step B, and maintaining temperature above the glass transition temperature of the polymeric film but below the temperature which would cause warping of the annular support, for a time sufficient to obtain a substantial absence of anisotropic stress distribution in the polymeric film.
Claim 11
Dependent Claim
201 words
A process for annealing a stretched surface recording disk comprising a rigid annular support, having at least two concentric raised annular reference surfaces and an annular polymeric film, having a recording layer, attached to the support and stretched between and supported by the raised annular reference surfaces, said process comprising: A. annealing a polymeric film which has been fixed in radial tension, at a temperature above its glass transition temperature for a time sufficient to obtain a substantial absence of anisotropic stree distribution in the film; B. bonding the annealed film from step A to the annular support at or near the inside and outside diameters of the support; and C. annealing the product of step B in an oven by placing the product of step B within a temperature dampening chamber within an oven, said temperature dampening chamber consisting essentially of a container larger than the annular support and a holding means for holding the product of step B, and maintaining temperature above the glass transition temperature of the polymeric film but below the temperature which would cause warping of the annular support, for a time sufficient to obtain a substantial absence of anisotropic stress distribution in the polymeric film.
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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) | 1991-03-08 | 1991-09-07 | 1992-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-08 | 1995-09-07 | 1996-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-08 | 1999-09-07 | 2000-03-08 | $7700.00 | Window Closed / Lapsed |