Phase compensator and compatible optical pickup using the phase compensator
US7180846B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 2002 |
| Grant date | Feb 20, 2007 |
| Priority date | — |
| Expiry date | Jun 15, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A compatible optical pickup for recording and/or reproducing information on/from multiple kinds of optical discs having different thicknesses by selectively using source lights of respective different wavelengths corresponding to a kind of disc and using a common objective lens. At least one phase compensator, which compensates a phase of a light having a particular wavelength to correct for spherical aberration due to a thickness difference between the kinds of optical discs and/or chromatic aberration due to a wavelength difference between the required source lights, is positioned between the source lights and an entrance pupil of the objective lens. Each phase compensator compensates light of at least one wavelength and passes light of at least one other wavelength without significant relative phase alteration. By using two phase compensators, the optical pickup may be made compatible with at least three kinds of optical discs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.