Information reading and recording apparatus
US6944111B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 2002 |
| Grant date | Sep 13, 2005 |
| Priority date | — |
| Expiry date | Oct 28, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An information reading and recording apparatus includes a super-resolution cut-off filter having an annular metal reflection film at its center portion and disposed immediately before one of two objective lenses with a higher NA. When reading DVD, the one objective lens with a higher NA with the super-resolution cut-off filter disposed therebefore is positioned at the optical path. When reading CD, the other objective lens with a lower NA is positioned at the optical path. The laser beam reflected by a disk follows backward the incoming optical path to pass through a half mirror, and is received by a photo-detector to be converted into an electrical signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.