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US 4,365,257 AGranted
Stretched-film optical recording disc
AssigneeMinnesota Mining and Manufacturing Company
InventorSten R. Gerfast
Life of this patent
Estimating the term…
Abstract
Optical recording disc having a rigid, dimensionally-stable support which keeps a plastic film taut and flat so that an optically-recordable coating on the plastic film resists the dimensional changes and warping which it otherwise might experience if unsupported. The optically-recordable coating may include an energy-absorbing layer which develops discontinuities immediately upon impingement by a focused laser beam and thus provides DRAW capability.
Claims9
An optical recording disc comprising
- a rigid, dimensionally-stable support,
- a thin, strong, tough plastic film which is tautly secured to said support to provide a broad, generally circular, flat area which is normally not in contact with the support, and
- a thin, uniform, optically-recordable coating substantially covering said broad out-of-contact area of the plastic film, which coating is substantially free from particles greater than 0.05 micrometer and has a Light-Scattering Value as herein defined of less than 5%.
Dependencies are inferred from the claim text.