Erasable optical data storage medium and method and apparatus for recording data on the medium
AssigneeOptical Data, Inc.
InventorsClyde D. Feyrer, N. Ross Gordon, W. Eugene Skiens
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Abstract
An erasable optical data storage medium including a substrate and a dual layer of a first material and a second material on the substrate. The dual layer is susceptible to expansion and contraction, to writing data thermally, to erasing data thermally and mechanically, and to reading data optically, the first material and the second material, respectively, being bonded together and remaining in the same physical state upon the expansion and relaxation of the dual layer. Methods and apparatus are also disclosed for recording data bits on the medium.
Claims13
A method of writing data in an optical data storage medium having a first layer of an elastic first material and a second layer of a second material having a glass transition temperature, said method comprising:
- (a) heating said first material to thermally expand said first material within its elastic limit;
- (b) raising said second material above its glass transtion temperature permitting said expanding first material to deform said second layer;
- (c) cooling said medium so that said second material falls below its glass transition temperature while said first material is in expanded condition;
- and
- (d) causing said second layer to hold said first material in expanded condition, storing mechanical energy in said layers.
A method of writing data in an optical data storage medium having a first layer of a first material and a second layer of a second material, said method comprising:
- (a) heating said first material to thermally expand said first material;
- (b) permitting said expanding first material to deform said second layer causing an optically detectable deformation;
- (c) cooling said medium;
- (d) causing said second layer to hold said first material in stretched expanded condition, storing mechanical energy in said layers;
- and
- (e) wherein said first material is adpated to substantially absorb radiant energy of a first preselected wavelength, said method including generating a laser beam of said first preselected wavelength and causing it to pass substantially through said second layer and be absorbed by said first material.
A method of writing data in an optical data storage medium having a first layer of a first material and a second layer of a second material, said method comprising:
- (a) heating said first material to thermally expand said first material;
- (b) permitting said expanding first material to deform said second layer causing an opticallyh detectable deformation;
- (c) cooling said medium;
- (d) causing said second layer to hold said first material in stretched expanded condition, storing mechanical energy in said layers;
- and
- (e) wherein said first and second materials are amorphous.
Dependencies are inferred from the claim text.