Recorder and antireflective record blank having an optically passive transparent layer
US4195312A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 1978 |
| Grant date | Mar 25, 1980 |
| Priority date | — |
| Expiry date | Feb 24, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/25715
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical record blank structure comprises a disc-shaped substrate (e.g., glass), a layer of light-reflective material (e.g., aluminum) overlying a surface of the disc-shaped substrate, a coating of a transparent material (e.g., silicon dioxide) overlying the light-reflective layer and a coating of a moderately absorptive material (e.g., an organic dye such as fluorescein) overlying the dielectric coating. The coating parameters are chosen to establish an antireflective condition to a recording light beam incident on the disc surface. The transparent coating thickness is selected such that the transparent coating is optically passive to the recording light beam, i.e., the thickness of the transparent coating is selected to be an integer multiple of the half-wavelength of the recording light beam wavelength in the transparent material. With this structure the efficiency of energy coupling into the absorptive coating is enhanced by the antireflective condition, the reflective surface of the substrate and the thickness of the transparent coating.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.