Information recording disk, its production method and recording apparatus
US5548454A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1990 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Jan 25, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B23/0035
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In the information recording disk, the positioning signal of the information convertor is provided permanently, as a change in shape or material, to the front and reverse surfaces of the disk substrate and their eccentric distances from the center position is made to be smaller than half the repeating unit length of the positioning signal of the information convertor in the radial direction. The start position of the positioning signal in the circumferential direction is preferably made to be coincident on the front and reverse surfaces of the disk substrate within 10 .mu.m. The position reference for aligning the position in the radial direction or the position reference for aligning the rotation angle position in the circumferential direction is preferably disposed on the inner diameter portion or outer diameter portion of the disk substrate, respectively, and these position references can be accomplished by disposing at least one notch on the inner or outer peripheral edge portion of the disk substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.