Laser noise elimination circuit and optical disc device
US7590157B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 2004 |
| Grant date | Sep 15, 2009 |
| Priority date | — |
| Expiry date | Nov 24, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1263
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A laser noise elimination circuit raises the gain of a first TIA and at the same time reflected light from an optical disc of a laser beam is subjected to photoelectric conversion by means of a photo detector and a second TIA to obtain an RF signal. Then, the direct current component of the FPD signal obtained by photoelectric conversion of part of the laser beam by means of another photo detector and the first TIA is cut out by a high pass filter and then subtracted by a subtracter. The gain of the first TIA is raised in a read mode of operation for reading data from the optical disc and lowered in a write mode of operation for writing data onto the optical disc so as to always effectively eliminate only the laser noise from the RF signal and prevent the circuit from being saturated in a write mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.