Optical data recording device
US4789977A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1986 |
| Grant date | Dec 6, 1988 |
| Priority date | — |
| Expiry date | Nov 6, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1353
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical data recording device for focusing a laser beam on a recording medium for storing and reading out information therefrom. The device is characterized by using a high efficiency holographic grating as a polarization beam splitter. In a forward collimated light path the holographic grating diffracts a light beam from a laser on an objective lens. The beam is reflected from the surface towards the recording medium and transmitted through the grating onto a light detector. The grating further provides for correcting a typical elliptical light beam shape from the laser to a circular beam shape as well as for correcting the astigmatism typically found in the wave fronts emitting from a laser diode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.