US 4,825,430 A · Erasable optical data storage medium having an embedded servo track and a subsurface recording interface

Abstract

An erasable optical data storage medium has an embedded servo track and a subsurface recording interface. An erasable recording structure having two dyed polymer layers is separated from the servo track by a compression layer. The servo track is formed in a hard substrate which provides mechanical support for the medium. The medium is adapted to form non-vesicular data bumps projecting into the compression layer when exposed to a write laser beam of predetermined wavelength projected through the substrate and compression layer. The embedded servo track and recording interface are sufficiently close to each to be read simultaneously in the same focal plane.

Claims16

Dependent claims

An optical data storage medium comprising:

(a) a substrate;
(b) a recording structure;
(c) a compression layer intermediate said substrate and said recording structure;
(d) said substrate and said compression layer defining a first interface, said medium including a servo track formed at said first interface;
(e) said recording structure including a retention layer and an expansion layer integrally bonded to each other, said retention layer arranged adjacent to said compression layer defining a recording interface therewith;
and
(g) said retention layer and said expansion layer defining a second interface, the thickness of said retention layer being such that the respective reflectance from said recording interface and said second interface constructively interfere with each other for light of predetermined wavelength.

4 more elements

Dependencies are inferred from the claim text.

Erasable optical data storage medium having an embedded servo track and a subsurface recording interface

Life of this patent

Erasable optical data storage medium having an embedded servo track and a subsurface recording interface

Life of this patent

Abstract

Claims16