Short wavelength optical disk head having a changeable aperture
US5281797A · kind A · utility
76Cited by
3References
10Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1992 |
| Grant date | Jan 25, 1994 |
| Priority date | — |
| Expiry date | Dec 23, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disk head having a short wavelength light source has an aperture diaphragm placed in the course of its focusing optical system which can change its aperture diameter depending on the pit size on an optical disk in order to allow recording on and reproducing from not only a short wavelength optical disk, but also a long wavelength optical disk. The aperture diameter is made larger for the smaller pit size and vice versa, and the light source output is adjusted depending on the aperture diameter so that the light amount coming from the disk surface to a photodetector cannot be changed with the aperture diameter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.