Optical information recording apparatus including means for delaying servo gain by a predetermined time
US5138596A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 6, 1991 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Nov 6, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0941
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical information recording apparatus according to the present invention prevents the saturation of an output of an amplifier, and thereby effects stable tracking and/or focusing servo. The recording apparatus includes a device for inputting an input signal modulated between at least two levels which are not zero in accordance with recording information, a device for converging a light beam intensity modulated between at least two levels which are not zero into a spot-like shape in accordance with the input signal, for scanning a recording medium, and for recording the information, a device for detecting a signal indicative of a positional error between the light beam spot and the medium in at least one of a focusing direction and a tracking direction, a servo device for correcting the positional error on the basis of the detected signal, a device for changing a gain of the servo in accordance with an intensity level of the light beam, and a device for delaying the gain by a predetermined time corresponding to a time period for a change in the level of the input signal from a higher level to a lower level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.