Duel-layer optical scanner with non-periodic phase structure element of birefringent material for different wavefront aberration compensation of orthogonally polarized radiation beams
US6947368B2 · kind B2 · utility
5Cited by
7References
22Claims
0Family size
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Key dates
| Filing date | Dec 7, 2001 |
| Grant date | Sep 20, 2005 |
| Priority date | — |
| Expiry date | Jan 29, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical scanning device for scanning a dual-layer optical record carrier with dual orthogonally polarized radiation beams. The device having a spherical aberration compensation optical subsystem including a switchable liquid crystal cell of birefringent material for altering different optical paths lengths provided by a phase structure of stepped annular zones.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.