Objective optical system for optical recording media and optical pickup device using it
US7613098B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 2005 |
| Grant date | Nov 3, 2009 |
| Priority date | — |
| Expiry date | Jul 12, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective optical system focuses light from a light source onto at least two different types of optical recording media having different substrate thicknesses in order to record or reproduce information on the optical recording media by using a variable refractive power element and an objective lens. The variable refractive power element may be a liquid crystal element with concentric zones that serves as a transparent plate having no convergence effect when no voltage is applied when selecting an AOD, DVD, or CD and as a converging lens when a voltage is applied when selecting a BD. Alternately, the variable refractive power element may electrically vary the refractive index of a nanoparticle dispersion or at least one liquid of a two-liquid lens element. A diffractive optical element may be used to assist in focusing light to four recording media. An optical pickup device includes the objective optical system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.