Optical information medium having high resolution beyond a diffraction limit and reading method
US6965556B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 2000 |
| Grant date | Nov 15, 2005 |
| Priority date | — |
| Expiry date | Aug 16, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/24
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an optical information medium having an information bearing surface having projections and depressions and/or capable of forming recorded marks, a functional layer is added. The information borne on the information bearing surface can be read by using reading light of a wavelength longer than 4NA·PL wherein PL is the minimum size of the projections and depressions or the recorded marks and NA is the numerical aperture of a reading optical system, setting the power of the reading light within such a range that the functional layer does not change its complex index of refraction, and irradiating the reading light to the information bearing surface constructed by the functional layer or to the information bearing surface through the functional layer or to the functional layer through the information bearing surface. The medium enables reading at a high resolution beyond the diffraction limit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.