Optical data recording apparatus producing a laser beam having a diameter larger than optical media groove width
US5982739A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 17, 1994 |
| Grant date | Nov 9, 1999 |
| Priority date | — |
| Expiry date | Oct 17, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/24079
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an optical data recording media provided with a recording layer which changes its optical characteristics by the difference of heat history of heating and cooling by the irradiation of the laser light to a transparent substrate on which tracking channels have been formed. The width of an extruded or concave region formed by the tracking channels on the substrate is narrower than the diameter of the laser beam being used for recording, erasing and reading. Thereby, a problem which is associated with the recording frequency-dependent erasing efficiency in a case where the pulse width modulation method is used as the modulation method, can be solved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.