Optical data recording disc with protrusion between clamping area and center hole
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsKazuhiro Hayashi, Eiji Ohno, Masanari Mohri
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Abstract
A disc-shaped optical data recording medium has a signal recording layer for reading and/or writing data using light, and a 10 μm to 200 μm thick transparent protective layer disposed over the signal recording layer. The optical data recording medium includes a protrusion projecting from a surface of the transparent protective layer on a light-incidence surface side to which light is emitted to the signal recording layer. The protrusion is disposed in an area between a center hole and a clamping area where the optical data recording medium is held when reading and/or writing data in the signal recording layer.
Claims3
An optical disc with a center hole, the optical disc comprising:
- a signal substrate;
- a signal recording layer for storing data;
- a transparent protective layer having a 10 μm to 200 μm thickness disposed over said signal recording layer;
- and
- a protrusion projecting from a surface of said transparent protective layer, wherein a signal area of the optical disc is located over said signal recording layer,
- a clamping area of the optical disc is located between the signal area and the center hole, and
- said protrusion is disposed at an area of the optical disc between the center hole and the clamping area,
- wherein the center hole has a 15 mm diameter,
- the optical disc has a 120 mm outside diameter, and
- the clamping area is located between a 22 mm diameter and a 33 mm diameter.
Dependencies are inferred from the claim text.