Optical pickup
US6594091B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 2001 |
| Grant date | Jul 15, 2003 |
| Priority date | — |
| Expiry date | Dec 3, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/13925
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to an optical pickup having a constant numerical aperture even if spherical aberration is compensated for. The optical pickup is used in an information recording and/or reproducing machine. The information recording and/or reproducing machine records and/or reproduces information in a recording medium upon radiation of a light beam from a light source. The optical pickup includes a condensing optical system for condensing the light beam from the light source onto a recording layer of the recording medium. The condensing optical system includes an object lens. The condensing optical system also includes an aperture positioned about a focal length of the object lens apart from a position of a principal incidence plane of the object lens toward the light source along an optical axis of the condensing optical system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.