Recording reproducing optical system, objective lens, and aberration correcting optical element
US7327663B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2003 |
| Grant date | Feb 5, 2008 |
| Priority date | — |
| Expiry date | Apr 22, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A recording reproducing optical system for an optical information recording medium is provided with a light source; an objective lens; and an aberration correcting optical element provided on an optical path between the light source and the objective lens. The objective lens includes an aspherical surface and one diffractive surface on which a diffractive structure structured by a plurality of concentric ring-shaped zonal steps is formed and the objective lens is a plastic lens structured in one element in one group. The aberration correcting optical element comprises at least one plastic lens on which a diffractive structure structured by a plurality of concentric ring-shaped zonal steps is formed. The following formulas are satisfied: PD1>0 (PD1 is a diffractive power (mm−1)), PD2<0 (PD2 is a diffractive power (mm−1)) and PR2>0 (PR2 is a refractive power (mm−1) as a refractive lens).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.