Optical element, aberration correcting element, light converging element, objective optical system, optical pickup device, and optical information recording reproducing device
US7369481B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 15, 2004 |
| Grant date | May 6, 2008 |
| Priority date | — |
| Expiry date | May 27, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical system for use in an optical pickup apparatus comprises a first optical surface having a superposition type diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each ring-shaped zone is composed of a plurality of stepped sections stepwise, and a second optical surface having a diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each of the plurality of ring-shaped zones are divided by a stepped section to generate a diffractive light ray of diffractive order whose absolute value is not small than 1 for the light flux.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.