Optical recording medium and method for eliminating berm buildup
US5741627A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 1996 |
| Grant date | Apr 21, 1998 |
| Priority date | — |
| Expiry date | May 15, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/261
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention discloses a method and an apparatus for creating an optical disc master by forming pits having ideal shapes and without berm buildup. These ideally shaped pits are improvements in the technology of disc mastering, due to the manufacturing and data playback advantages that are inherent in the ideally shaped pits. A disc substrate has a very thin partially reflective layer applied to the surface of the optical disc upon which data will be recorded. The substance used to make the partially reflective layer is normally considered opaque in more commonly occurring thicknesses. However, the partially reflective layer, is created to be so extremely thin that it becomes partially optically transparent. The partially reflective layer then has spin coated, thereon, an optically active lamina to enable the recording of data on the disc by laser means in the form of pits. The pits are created by having a laser light focusing on both the partially reflective layer and the optically active lamina, both which react to the irradiation causing a pit to be formed. The resulting pit more often than not possesses a residual raised berm area surrounding the pit, in what is considered to b…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.