Method for making a broadband reflective laser recording and data storage medium with absorptive underlayer
US4312938A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1980 |
| Grant date | Jan 26, 1982 |
| Priority date | — |
| Expiry date | Oct 17, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/165
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A broadband laser recording and data storage medium for direct read after writing, formed from a photosensitive silver-halide emulsion in four steps. First, a non-saturating actinic radiation exposure is used to create latent images. A normal photographic development is used to produce a medium of gray neutral density. The surface of the remaining silver halide is fogged in a water or alcohol based solution to create a very thin layer of silver precipitating nuclei on the surface. Finally, a single-step, negative silver diffusion transfer process is used to dissolve the unexposed and undeveloped silver halide, forming silver ion complexes. These complexes are transported by diffusion transfer to the sites of the silver precipitating nuclei and the filamentary silver on the surface, where the silver complexes are reduced to metallic silver on both the nuclei and the filamentary silver to form a high concentration of non-filamentary silver particles at the surface of a low melting temperature colloid matrix which is highly reflective of light and electrically non-conducting.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.