Laser power control of an optical head with a plurality of beam sources
US5469423A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 1994 |
| Grant date | Nov 21, 1995 |
| Priority date | — |
| Expiry date | Jun 2, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1398
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording apparatus which reduces light loss by expanding the laser beam diameters irradiated from a plurality of beam sources, and reducing the expanded beam diameters immediately before focusing the beams onto an information recording/reproducing medium to make the beams circular, thereby minimizing deviation of the laser beam from the optical axis. An optical system for use in recording apparatus with a multi-beam optical head provided with a plurality of laser beam sources in a fixed unit which reduces light loss by minimizing deviation of the laser beam from the optical axis, and also by maintaining the laser power of each laser beam at a predetermined intensity independent of changes in distance between the fixed unit half and the moving unit half of the optical system by detecting intensities of the laser beams focused on a recording medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.