Aberration compensating optical element, optical system, optical pickup device, recorder and reproducer
US6865025B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 5, 2003 |
| Grant date | Mar 8, 2005 |
| Priority date | — |
| Expiry date | Dec 5, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An aberration compensating optical element includes: a diffractive structure having a plurality of ring-shaped zone steps formed into substantially concentric circles on at least one surface of the aberration compensating optical element; wherein the aberration compensating optical element is adapted for being disposed on an optical path between a light source for emitting a light having a wavelength of not more than 550 nm, and an objective lens made of a material having an Abbe constant of not more than 95.0 at a d-line; and wherein the following inequality is satisfied: Pλ1<Pλ0<Pλ2, where Pλ0 is a paraxial power (mm−1) of the aberration compensating optical element at the wavelength λ0 of the light emitted from the light source; Pλ1 is a paraxial power (mm−1) of the aberration compensating optical element at a wavelength λ1 which is 10 nm shorter than the wavelength λ0; and Pλ2 is a paraxial power (mm−1) of the aberration compensating optical element at a wavelength λ2 which is 10 nm longer than the wavelength λ0.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.