Device for writing and/or reading optical recording medium of various designs
US6285641A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1998 |
| Grant date | Sep 4, 2001 |
| Priority date | — |
| Expiry date | Sep 3, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2019/121
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A device for writing to and/or reading from optical recording media having different structures is described, for example, a device which is suitable both for writing to/reading from digital videodisks (DVD) and conventional CD's. Provision is made for measuring the intensity of each peak in the mirror signal while the objective lens is moving to the recording medium. The intensity e.g. at the instant of the positive-negative crossing of the focus error signal is taken in this case. The type of optical recording medium is determined from the time characteristic and/or the height distribution of the peaks. In order to identify the type of optical recording medium, different properties of the optical recording medium are taken into account, such as reflectivity of the corresponding reflective surface, reduced intensity modulation due to spherical aberration, time characteristic and the like.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.