Pickup for optical disc
US4733943A · kind A · utility
39Cited by
2References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1983 |
| Grant date | Mar 29, 1988 |
| Priority date | — |
| Expiry date | Nov 17, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1353
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A pickup system for an optical disc reading/recording apparatus in which a micro Fresnel lens, formed with concentric circular gratings, is used in place of an optical element, such as an objective lens, for focussing and collimating light beams from a semiconductor light source. The pickup system so formed is light in weight, easily miniaturized, and inexpensive to manufacture. The micro Fresnel lens can be formed as an integral unit with the semiconductor laser by mounting the lens in a window of the case of the semiconductor laser.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.