Optical head and optical information recorder/reproducer
US7773468B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 11, 2006 |
| Grant date | Aug 10, 2010 |
| Priority date | — |
| Expiry date | Oct 1, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Fifth order spherical aberration in addition to third order spherical aberration for an optical information recording medium of which thickness of a light transmission layer changes greatly is corrected. An objective lens collects a laser beam emitted from a semiconductor laser on an optical information recording medium. A spherical aberration correcting portion corrects spherical aberration generated according to a thickness of the light transmission layer of the optical information recording medium, in which the spherical aberration correcting portion includes a collimator lens, a lens holder and a stepping motor for correcting the third order spherical aberration and a liquid crystal element and an applied voltage control portion for correcting the fifth order spherical aberration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.