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US 6,603,733 B2Granted
Optical information medium
AssigneeTDK Corporation
InventorsTakuya Tsukagoshi, Jiro Yoshinari
Life of this patent
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AssigneeTDK Corporation
InventorsTakuya Tsukagoshi, Jiro Yoshinari
Estimating the term…
An optical information disk with an excellent mechanical precision is provided. Also provided is a multi-layer optical disk having a plurality of data layers wherein every data layer exhibits sufficient properties in reading. In addition, such multi-layer optical disk is provided at a low cost. The optical information comprises a disk-shaped substrate or a pair of disk-shaped substrates, and at least one annular data layer for storing at least recorded information and at least one annular resin layer disposed on said disk-shaped substrate or between said pair of disk-shaped substrates. In this medium, at least one of the substrate(s) has a configuration such that its surface facing toward the data layer is convex, and at least one of said resin layer(s) is formed such that it is thicker near its outer periphery compared to the region near its inner periphery.
An optical information medium comprising a disk-shaped substrate or a pair of disk-shaped substrates, and at least one annular data layer for storing at least recorded information and at least one annular resin layer disposed on said disk-shaped substrate or between said pair of disk-shaped substrates, wherein
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the…:…
Laminated discs: adhesion or bonding, e.g. specific adhesive layers
Recording layers: multiple laminated recording layers
Layers; Shape, structure or physical properties thereof: substrates
Term ended 2 Mar 2022 (estimated)
1. Field of the Invention
This invention relates to an optical disk.
2. Prior Art
FIG. 1 is a cross-sectional view of the optical information medium according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the optical information medium according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view of the optical information medium according to another embodiment of the present invention.
The information medium to which the present invention is applied has a data layer. A “data layer” is the layer wherein record marks and pits carrying the recorded information are present, and a tracking servo pattern comprising projections and depressions such as grooves and pits may also be formed on the data layer. It is also possible to provide a servo layer formed with tracking servo pattern independently from the data layer where no tracking servo pattern is formed. In the present invention, the term “information-storing layer” may be used to refer to both the data layer and the servo layer.
In the present invention, the beam used in the reading of the data layer and the recording of the data layer is designated the “data beam” and the beam used in the reading of the servo layer is designated the “servo beam”. The “recording/reading beam” of the present invention is a concept including the data beam and the servo beam.
The “multi-layer information medium” of the present invention is a medium comprising a plurality of information-storing layers, and which includes an information-storing layer whose recording and/or reading is accomplished by the recording/reading beam which has passed through other information-storing layer(s).