US4339532A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Novel photosensitive silver halide emulsion and method of preparing same
Assignee: Polaroid Corp
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Filing: 1981-01-08
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Granted: 1982-07-13
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Expires: 2001-01-08
Abstract
Abstract Monodisperse, negative working photosensitive silver halide emulsions comprising grains having a uniform habit and relatively high degree of crystal disorder are prepared by precipitating silver halide in the presence of a seed emulsion which is predominantly silver chloride under conditions whereby substantially none of the silver chloride of said seed emulsion is redissolved and substantially no additional grains are formed.
Inventors
- 👤 Leo D. Corben
- 👤 Martin L. Falxa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:32
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/015; G03C1/035; G03C2001/0357
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
73 words
A method for forming a monodisperse, negative-working silver halide emulsion comprising silver chlorobromide or silver iodochlorobromide wherein said grains have a relatively high level of internal disorder in the crystal structure and a uniform habit which comprises precipitating silver halide in the presence of a monodisperse, predominantly silver chloride seed emulsion having a cubic habit under conditions wherein substantially none of the silver chloride is redissolved and substantially no additional grains are formed.
Claim 2
Independent Claim
73 words
A method for forming a monodisperse, negative-working silver halide emulsion comprising silver chlorobromide or silver iodochlorobromide wherein said grains have a relatively high level of internal disorder in the crystal structure and a uniform habit which comprises precipitating silver halide in the presence of a monodisperse, predominantly silver chloride seed emulsion having a cubic habit under conditions wherein substantially none of the silver chloride is redissolved and substantially no additional grains are formed.
Claim 3
Dependent Claim
22 words
The method as defined in claim 1 wherein said precipitation is carried out at a pAg of between about 7 and 9.
Claim 4
Dependent Claim
33 words
The method as defined in claim 1 wherein said seed emulsion is prepared by precipitating silver chloride at a pAg of about 2.5 to 6 and a pH of less than about 7.
Claim 5
Dependent Claim
19 words
The method as defined in claim 3 wherein said pAg is about 4 and said pH is about 5.6.
Claim 6
Dependent Claim
33 words
The method of claim 3 or 4 wherein said seed emulsion is not removed from the vessel in which it is formed and said precipitation of silver halide is carried out substantially immediately.
Claim 7
Dependent Claim
21 words
The method of claim 1 wherein said silver halide precipitation is carried out in the presence of an unwashed seed emulsion.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein said seed emulsion is prepared under radiation actinic to silver chloride.
Claim 9
Dependent Claim
52 words
The method of claim 1 wherein the halide of said seed emulsion comprises about 51-100% chloride, 0-49% bromide and 0 to 49% iodide, and the halide content of said silver halide precipitated in the presence of said seed comprises 75 to 100% bromide, 0 to 20% chloride and 0 to 20% iodide.
Claim 10
Dependent Claim
15 words
The method of claim 8 wherein the halide of the seed emulsion is 100% chloride.
Claim 11
Dependent Claim
14 words
The method of claim 1 wherein said seed emulsion ranges from about 0.15-2.0 μm.
Claim 12
Independent Claim
93 words
A method for forming a monodisperse, negative-working silver halide emulsion comprising silver chlorobromide or silver iodochlorobromide grains wherein said grains have a relatively high level of internal disorder and a uniform habit in the crystal structure and which comprises the steps of precipitating predominantly silver chloride grains at a pAg of about 2.6 to 6 and a pH less than about 7 and then precipitating silver halide in the presence of said silver chloride grains under conditions wherein substantially none of the silver chloride is dissolved and substantially no additional grains are formed.
Claim 13
Independent Claim
93 words
A method for forming a monodisperse, negative-working silver halide emulsion comprising silver chlorobromide or silver iodochlorobromide grains wherein said grains have a relatively high level of internal disorder and a uniform habit in the crystal structure and which comprises the steps of precipitating predominantly silver chloride grains at a pAg of about 2.6 to 6 and a pH less than about 7 and then precipitating silver halide in the presence of said silver chloride grains under conditions wherein substantially none of the silver chloride is dissolved and substantially no additional grains are formed.
Claim 14
Dependent Claim
107 words
A monodisperse, negative-working silver halide emulsion comprising silver chlorobromide or silver iodochlorobromide grains having a relatively high degree of crystal disorder and uniform habit wherein said crystal disorder measured by determining the Bragg angle for said grains and plotting β cos θ vs 2 sin θ, wherein β is the breadth of the peak (at half-height) at Bragg angle θ, provide a plot having a slope at least 2 times the slope plotted for a silver bromide grain wherein said emulsion is maintained at a temperature and in a chlorobromide environment as determined by the chloride content of said grains to prevent chloride loss from said grains.
Claim 15
Dependent Claim
107 words
A monodisperse, negative-working silver halide emulsion comprising silver chlorobromide or silver iodochlorobromide grains having a relatively high degree of crystal disorder and uniform habit wherein said crystal disorder measured by determining the Bragg angle for said grains and plotting β cos θ vs 2 sin θ, wherein β is the breadth of the peak (at half-height) at Bragg angle θ, provide a plot having a slope at least 2 times the slope plotted for a silver bromide grain wherein said emulsion is maintained at a temperature and in a chlorobromide environment as determined by the chloride content of said grains to prevent chloride loss from said grains.
Claim 16
Dependent Claim
20 words
The emulsion of claim 12 wherein said slope is at least 3 times the slope for a silver bromide grain.
Claim 17
Dependent Claim
23 words
The emulsion of claim 12 wherein the halide content of said grain comprises about 60-95% bromide; about 1-40% chloride and about 0-20% iodide.
Claim 18
Dependent Claim
13 words
The emulsion of claim 12 wherein said grains range from about 0.3-3.0 μm.
Claim 19
Dependent Claim
16 words
The emulsion of claim 12 wherein a dye image providing material is associated with said emulsion.
Claim 20
Dependent Claim
15 words
The emulsion of claim 16 wherein said dye image forming material is a dye developer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-12 | 1986-01-11 | 1986-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-12 | 1990-01-11 | 1990-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-12 | 1994-01-11 | 1994-07-13 | $7700.00 | Window Closed / Lapsed |