Optical pickup apparatus, objective lens, apparatus for reproducing and/or recording optical information recording medium
US6687209B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 2001 |
| Grant date | Feb 3, 2004 |
| Priority date | — |
| Expiry date | Jul 9, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup apparatus for at least two kinds of optical information recording media, comprises a first light source; a second light source; an optical converging system; and a photo detector. An optical element of the optical converging system comprises a first region including an optical axis and a second region adjoining the first region and locating at the outside of the first region, the first region is a refractive surface and the second region is a diffractive surface. When a first light flux passes through the second region, the light amount of n-th order diffracted ray of the first light flux is larger than that of any other order diffracted ray of the first light flux, and when a second light flux passes through the second region of the optical element, the light amount of n-th order diffracted ray of the second light flux is larger than that of any other order diffracted ray of the second light flux, where n is an integer except 0.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.