Method and apparatus for detecting light from a multilayered object
US6577584B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Apr 27, 2000 |
| Grant date | Jun 10, 2003 |
| Priority date | — |
| Expiry date | Apr 27, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1387
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for reproducing signals from a multi-layer structured recording object wherein a linearly polarized laser beam illuminate the multi-layer structured object, such as a phase change recording medium via an objective lens system having an effective numerical aperture greater than 0.6. A light beam reflective from the object is passed to a filtering mask disposed to receive the reflected light beam. The filtering mask includes a first area that has a first transmissivity and a second area having a second transmissivity different than the first transmissivity. The reflected laser beam passed through the filtering mask is detected to reproduce signals from the recording medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.