Method and apparatus for coupling an optical lens to a disk through a coupling medium having a relatively high index of refraction
US6236634A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 2000 |
| Grant date | May 22, 2001 |
| Priority date | — |
| Expiry date | Aug 11, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1374
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In one aspect, an optical recording system including an optical recording medium; a light source; a focusing lens that focuses light generated by the light source to form a focused beam of light directed toward the recording medium; and a coupling medium disposed between the lens and at least one portion of the optical recording medium, the coupling medium being transparent and having a refractive index greater than one. The coupling medium facilitates optical coupling between the lens and the recording medium. In another aspect, the coupling medium is disposed so that no air gap exists in the optical path between the lens and the recording medium. In another aspect, the exit surface of the lens is disposed at a distance from the recording medium that exceeds a distance that an evanescent wave of a high angle ray of the beam of light would travel after contacting air, but the system includes coupling means for coupling the ray of light from the lens to the recording medium. In another aspect, an optical recording medium is provided with at least one layer of fluid disposed atop the recording medium, the fluid being transparent and having a refractive index greater than one.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.