Optical data recording disc with protrusion between clamping area and center hole
AssigneePanasonic Corporation
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.
Claims9
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 thickness of 10 μm to 200 μm disposed over said signal recording layer;
- and
- a protrusion projecting from a surface of said transparent protective layer, wherein
- the optical disc has a clamping area adapted to be held when reading and/or writing data in the signal recording layer, and
- said protrusion is disposed at an area of the optical disc between the center hole and the clamping area,
- wherein the data is recorded to and/or read from the signal recording layer using an optical head with a numeric aperture of 0.85 to 0.9, and
- a wavelength of light for recording and/or reading the data in said signal recording layer is 410 nm or less.
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 thickness of 10 μm to 200 μm disposed over said signal recording layer;
- and
- a protrusion projecting from a surface of said transparent protective layer, wherein
- the optical disc has a clamping area adapted to be held when reading and/or writing data in the signal recording layer, and
- said protrusion is disposed at an area of the optical disc between the center hole and the clamping area,
- wherein the data is recorded to and/or read from the signal recording layer using an optical head with a numeric aperture of 0.7 to 0.9, and
- a wavelength of light for recording and/or reading the data in said signal recording layer is 405 nm or less.
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 thickness of 10 μm to 200 μm disposed over said signal recording layer;
- and
- a protrusion projecting from a surface of said transparent protective layer, wherein
- the optical disc has a clamping area adapted to be held when reading and/or writing data in the signal recording layer, and
- said protrusion is disposed at an area of the optical disc between the center hole and the clamping area,
- wherein the data is recorded to and/or read from the signal recording layer using an optical head with a numeric aperture of 0.85 to 0.9, and
- a wavelength of light for recording and/or reading the data in said signal recording layer is 405 nm or less.
Dependencies are inferred from the claim text.