Objective lens for optical pick-up apparatus and optical pick-up apparatus
US6747812B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 18, 2002 |
| Grant date | Jun 8, 2004 |
| Priority date | — |
| Expiry date | Nov 18, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens for use in an optical pickup apparatus in which first and second light sources are provided on a same flat surface, converges each of the light fluxes from the first and second light sources onto an information recording plane through each of transparent substrates of a first and second optical information recording mediums and has a coma aberration of 0.015 &lgr;1 rms or less when recording or reproducing information is conducted for the first optical information recording medium, and a coma aberration of 0.015 &lgr;2 rms or less when recording or reproducing information is conducted for the second optical information recording medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.