Objective lens and optical data storage apparatus comprising the objective lens
US8036094B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 20, 2010 |
| Grant date | Oct 11, 2011 |
| Priority date | — |
| Expiry date | Aug 20, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens is described, which is switchable between a far-field mode and a near-field mode. The objective lens comprises a lens, an optical element having a variable refractive index and a solid immersion lens, which are disposed on a common optical axis, wherein the optical element is arranged at a convex side of the solid immersion lens and has a top and a bottom surface arranged adjacent to each other in a direction of the optical axis, the bottom surface having a concave shape that is adapted to the shape of the convex side of the solid immersion lens and the top surface having a curvature that is lower than a curvature of the convex side of the solid immersion lens, and wherein a difference between a refractive index of the optical element and the solid immersion lens is small in the far-field mode so that the solid immersion lens and the optical element act substantially as a single optical element in the far-field mode, whereas the difference is large in the near-field mode so that the optical effect of the solid immersion lens is significant in the near-field mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.