Method of making double-sided magneto-optical disks having reduced birefringence
AssigneeE. I. Du Pont de Nemours and Company
InventorFred J. Harper
Life of this patent
Estimating the term…
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.
Claims7
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.sup.2 only to the non-information areas, thus forming an adhesive barrier between the recording sides of both disks.
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.sup.2 only upon the non-information areas of the disks.
Dependencies are inferred from the claim text.