# US 6,720,135 B2 · Silver halide photographic emulsion and silver halide photographic material by use thereof

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- Number: US 6,720,135 B2
- Document ID: US6720135B2
- Status: Granted
- Kind: B2
- Application number: 10/439,077
- Filed: 2003-05-15
- Published: 2003-12-04
- Granted: 2004-04-13
- Earliest claimed: 2002-05-23
- Assignees: Konica Corporation
- Inventors: Toshiya Kondo; Tadanobu Sekiya
- Web page: https://patentgrep.com/patent/US6720135B2

## CPC

- G03C 1/0051: {Tabular grain emulsions}
- G03C 1/08: Sensitivity-increasing substances
- G03C 2001/0055: {Aspect ratio of tabular grains in general; High aspect ratio; Intermediate aspect ratio; Low aspect ratio}
- G03C 2001/0056: {Disclocations}
- G03C 2001/0058: {Twinned crystal}
- G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G)

## Abstract

A silver halide emulsion improved in radiation resistance is disclosed, comprising tabular grains having an average aspect ratio of 20 to 500 and an average spacing between twin planes of 10 to 160 A, and at least 80% by number of the tabular grains being accounted for by hexagonal tabular grains having an adjacent edge ratio of not less than 1.0 and less than 1.2. There is also disclosed a photographic material comprising a silver halide emulsion layer containing the tabular grains.

## Claims

### Claim 1

A silver halide photographic emulsion comprising silver halide grains, wherein at least 70% of total grain projected area is accounted for by tabular grains, the tabular grains having an average aspect ratio of 20 to 500 and an average spacing between twin planes of 10 to 160 A, and at least 80% by number of the tabular grains being accounted for by hexagonal tabular grains having an adjacent edge ratio of not less than 1.0 and less than 1.2.

### Claim 2 (depends on 1)

The silver halide emulsion of claim 1, wherein at least 50% by number of the tabular grains is accounted for by grains having at least 30 dislocation lines in fringe portions of the tabular grains.

### Claim 3 (depends on 1)

The silver halide emulsion of claim 1, wherein at least 80% by number of the tabular grains is accounted for by hexagonal grains having an adjacent edge ratio of not less than 1.0 and not more than 1.1.

### Claim 4 (depends on 1)

The silver halide emulsion of claim 1, wherein the tabular grains have an average aspect ratio of 25 to 500.

### Claim 5 (depends on 1)

The silver halide emulsion of claim 1, wherein the tabular grains have an average equivalent circle diameter of 1.0 to 50.0 μm and an average thickness of 0.005 to 0.1 μm.

### Claim 6 (depends on 1)

The silver halide emulsion of claim 1, wherein heteromorphic grains accounts for 0 to 5% by number of total grains.

### Claim 7 (depends on 1)

The silver halide emulsion of claim 1, wherein the tabular grains contain at least one selected from the group consisting of a polyvalent metal atom, polyvalent metal ion, polyvalent metal complex and polyvalent metal ion complex.

### Claim 8

A silver halide photographic emulsion comprising silver halide grains, wherein the silver halide grains have an average aspect ratio of 20 to 500 and a spacing between twin planes of 10 to 160 A, and at least 80% by number of the silver halide grains is accounted for by hexagonal tabular grains having a adjacent edge ratio of not less than 1.0 and less than 1.2.

### Claim 9

A silver halide photographic material comprising on a support at least one silver halide emulsion layer, wherein the silver halide emulsion layer comprises a silver emulsion comprising silver halide grains, and at least 70% of total grain projected area is accounted for by tabular grains, the tabular grains having an average aspect ratio of 20 to 500 and an average spacing between twin planes of 10 to 60 A, and at least 80% by number of the tabular grains being accounted for by hexagonal tabular grains having an adjacent edge ratio of not less than 1.0 and less than 1.2.