Laser control device
US6683836B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 2001 |
| Grant date | Jan 27, 2004 |
| Priority date | — |
| Expiry date | Dec 23, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0062
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
When the modulation speed of the laser is increased, it is difficult to correctly detect a peak power and a bias power for controlling a laser power. The bias power current Ib is controlled by the operated value of the operation circuit 3 in accordance with the reproduction power current Ir control value of the servo amplifier 5 at the reproduction just before recording, and as for the erase power Pe, since its period is relatively long, the power is detected by the sample-hold circuit 4 and the erase power current Ie is controlled by the operation circuit 3, and the peak power PP is controlled by the operated value of the operation circuit 3 in accordance with the erase power current Ie, and therefore, a bottom hold circuit and a peak hold circuit are not required and the laser control apparatus which does not require the high-speed performance in a photodiode and a monitor circuit is realized to solve the above mentioned problem.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.