Global Patent Index - EP 0699949 A1

EP 0699949 A1 19960306 - Ultrathin tabular grain emulsions with dopants at selected locations

Title (en)

Ultrathin tabular grain emulsions with dopants at selected locations

Title (de)

Emulsionen mit ultradünnen tafelförmigen Körnern und Dotierungsmitteln auf ausgewählten Stellen

Title (fr)

Emulsions aux grains tabulaires ultraminces avec des dopants sur des places sélectionnées

Publication

EP 0699949 A1 19960306 (EN)

Application

EP 95420238 A 19950821

Priority

  • US 29743094 A 19940826
  • US 29656294 A 19940826
  • US 29719594 A 19940826
  • US 35925194 A 19941219
  • US 44113295 A 19950515

Abstract (en)

A chemically and spectrally sensitized ultra-thin tabular grain emulsion is disclosed including tabular grains (a) having ä111ü major faces, (b) containing greater than 70 mole percent bromide, based on silver, (c) accounting for greater than 90 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 mu m, and (e) exhibiting an average thickness of less than 0.07 mu m. Improved sensitivity is observed when the surface chemical sensitization sites include silver halide protrusions of a face centered cubic crystal lattice structure forming epitaxial junctions with the tabular grains and having a higher overall solubility than at least that portion of the tabular grains forming epitaxial junctions with the protrusions and a sensitivity enhancing combination of dopants are contained in the silver halide grains including a first sensitivity enhancing dopant capable of providing shallow electron trapping sites and a second sensitivity enhancing selenium dopant. To further enhance sensitivity, one of the sensitivity enhancing dopants is restricted to the tabular grains while the other is restricted to the silver halide epitaxy.

IPC 1-7

G03C 1/005; G03C 1/08

IPC 8 full level

G03C 1/035 (2006.01); G03C 1/005 (2006.01); G03C 1/08 (2006.01); G03C 1/09 (2006.01); G03C 1/10 (2006.01); G03C 1/46 (2006.01)

CPC (source: EP)

G03C 1/0051 (2013.01); G03C 1/08 (2013.01); G03C 1/46 (2013.01)

Citation (applicant)

Citation (search report)

Designated contracting state (EPC)

DE FR GB

DOCDB simple family (publication)

EP 0699949 A1 19960306; EP 0699949 B1 20000607; DE 69517373 D1 20000713; DE 69517373 T2 20010208; JP H08101472 A 19960416

DOCDB simple family (application)

EP 95420238 A 19950821; DE 69517373 T 19950821; JP 21773695 A 19950825