Optical head with forward and reflected light beams propagating through a dual diffraction grating device along a common path
US5684779A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1996 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Jan 11, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0912
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical head which records data onto an optical data recording medium and reproduces the data therefrom includes a laser light source, a collimator lens, an objective lens, a light splitting device arranged between the laser light source and the objective lens, for splitting the emitted light from the laser light and a reflected light from the optical data recording medium. A diffraction grating is provided to which only the reflected light split at the light splitting device is incident to, and which leads the reflected light split at the optical element onto a photo-detector. Thereby, an optical head of high effectiveness in utilization of light and low cost can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.