Cubical grain silver iodochloride emulsions and processes for their preparation
US5736310A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 1996 |
| Grant date | Apr 7, 1998 |
| Priority date | — |
| Expiry date | May 17, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/40
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Radiation sensitive emulsions are disclosed comprised of silver iodochloride grains having three pairs of equidistantly spaced parallel {100} crystal faces and containing from 0.05 to 3 mole percent iodide, based on total silver, in a controlled, non-uniform iodide distribution forming a core containing at least 50 percent of total silver, a surface shell, and a sub-surface shell that contains a maximum iodide concentration and provides, when the emulsion is exposed to 390 nm electromagnetic radiation at 10.degree. K., stimulated fluorescent emissions in the range of from 450 to 470 nm and at 500, the stimulated fluorescent emission in the range of from 450 to 470 nm having a peak intensity more than twice the stimulated fluorescent emission intensity at 500 nm. The emulsion is prepared by a process wherein a) grains accounting for at least 50 percent of total silver forming the silver iodochloride grains are grown in the dispersing medium, (b) while employing the grains as substrates for further grain growth, locating crystal lattice variances in the grains by the incorporation of iodide to form a first shell having a higher local iodide concentration than any other grain portion,…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.