Optical scanning device with a selective optical diaphragm
US6707779B2 · kind B2 · utility
1Cited by
4References
24Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 2, 2001 |
| Grant date | Mar 16, 2004 |
| Priority date | — |
| Expiry date | Feb 25, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/139
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical scanning device comprising means for scanning optical record carriers of predetermined different formats, such as CDs and DVDs, using scanning at different numerical apertures provided by an optical diaphragm. The optical diaphragm comprises cholesteric liquid crystal material of one or more selected helical pitches which provide the diaphragm with desired wavelength- and/or polarization-selective characteristics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.