Optical information medium
US6590856B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 2001 |
| Grant date | Jul 8, 2003 |
| Priority date | — |
| Expiry date | Jun 8, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/25718
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In the multi-layer information medium having a plurality of information-storing layers according to the present invention, distance between the adjacent information-storing layers is reduced with no increase in cross talk between these layers. The optical information medium has at least two information-storing layers each storing recorded information and/or servo information, and at least one of the information-storing layers is recorded or read by the recording beam or the reading beam which has passed through other information-storing layer(s). The medium has a filter layer between the adjacent information-storing layers, and in the spectral absorption characteristics in the wavelength range of 300 to 1000 nm of this filter layer, a wavelength range exhibiting an absorption of 80% or higher and a wavelength range exhibiting an absorption of 20% or lower are present.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.