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US 7,065,034 B2Granted
Optical disc and apparatus for manufacturing a master disc therefor
AssigneePioneer Corporation
InventorMasahiro Katsumura
Life of this patent
Estimating the term…
Abstract
A master-disc-manufacturing apparatus includes an electron-beam emitting portion for emitting an electron beam, an electron-beam converging portion for converging an electron beam, a retarding voltage applying portion for applying a substrate with a negative potential having a magnitude of decelerating the electron beam, and a vacuum atmosphere producing portion for evacuating a chamber to produce a vacuum atmosphere therein.
Claims1
An optical disc comprising:
- a disc substrate;
- a land and a groove spirally or concentrically formed on the disc substrate wherein the groove has a line width stretched in a radial direction of said disc substrate;
- and prepits formed on the land or the groove, wherein each of the prepits has an internal diameter stretched in a tangential direction of said disc substrate, characterized in that said internal diameter of the prepit is shorter than said line width of the groove,
- wherein said line width of the groove is in a range of v<h≦3v wherein h denotes the line width and v denotes the internal diameter of the prepit, and
- wherein said internal diameter of the prepit is in a range of from 100 nm to 300 nm.
2 more elements
Dependencies are inferred from the claim text.