Patent · US Active

Objective lens and optical pickup comprising the objective lens

US8054734B2 · kind B2 · utility

0Cited by

2References

15Claims

0Family size

Assignee

Thomson Licensing · FR

Inventors

Stephan Knappmann · Zimmern ob Rottweil, DE
Joachim Knittel · Tuttlingen, DE
Juergen Moessner · Brigachtal, DE

Key dates

Filing date	Aug 23, 2010
Grant date	Nov 8, 2011
Priority date	—
Expiry date	Aug 23, 2030

Classification

Technology area (CPC G)Physics
CPC primaryG11B2007/13727
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

Optical pickup 24 for operation in the far-field and in the near-field mode comprising a movable part 26 having an objective lens 2 comprising a solid immersion lens 4 and a multifocal lens 6, which are both disposed on a common optical axis A. The multifocal lens 6 comprises a central zone 8 and a peripheral zone 10 being circumferential to the central zone 8. The peripheral zone is adapted to constitute an optical system for a far-field mode. The central zone 8 of the multifocal lens 6 together with the solid immersion lens 4 are adapted to constitute an optical system for a near-field mode. The solid immersion lens and the multifocal lens are adapted to be moved in unison. A method for operating an optical pickup 24 comprises a first approach to a surface 21 of an optical storage medium 22 with the movable part 26 to reach a far-field working distance DF based on a focus control using an optical system for working in the far-field mode, and a subsequent approach to the surface 21 of the optical storage medium 22 which is performed by lowering the far-field working distance DF to a smaller near-field working distance NF.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.