Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-11-14
2003-03-25
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S567000, C430S574000
Reexamination Certificate
active
06537742
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a spectrally sensitized silver halide photographic emulsion and a method for producing the same and, further, relates to a silver halide photographic material containing said emulsion.
BACKGROUND OF THE INVENTION
The sensitivity of a silver halide photographic material is determined by the light absorption factor of a grain, latent image forming efficiency including spectral sensitization efficiency and a minimum size of a latent image.
Of these factors, as to techniques of improving the light absorption factor of a grain, some which are known heretofore are shown below.
Techniques of high aspect ratio tabular grain emulsions disclosed in U.S. Pat. No. 5,494,789, etc., are techniques capable of increasing a dye adsorption amount per one grain because a tabular grain has a larger grain surface area, as a result, the light absorption factor can be improved. However, there are limitations in the increase of the surface area of a grain by heightening an aspect ratio and the like, therefore, a larger sized grain is necessary to improve the light absorption factor of one grain.
In addition to the above, as methods of increasing the grain surface area per one grain, methods of making a pore at a part of a grain are disclosed in JP-A-58-106532 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and JP-A-60-221320, and a ruffled grain is disclosed in U.S. Pat. No. 4,643,966. However, the forms of grains according to these methods are unstable and accompanied by extreme difficulties in practical use.
Further, U.S. Pat. No. 5,302,499 discloses that a light absorption factor can be improved by constituting the layer structure having spectral sensitization characteristics and optimal grain thicknesses. But the improvement of a light absorption factor by the optimization of the grain thicknesses is at most 10% or so.
Accordingly, for markedly improving a light absorption factor of one grain while maintaining a grain size small with a stable grain form, it is necessary to improve the light absorption factor per unit surface area of a grain. For that sake, it is necessary to heighten the adsorption density of a sensitizing dye, but a generally used spectral sensitizing dye is adsorbed onto a monolayer with almost the closest charging and is adsorbed no more.
Methods which have been proposed for a sensitizing dye to be multilayer adsorbed onto a grain surface are shown below.
In P. B. Gilman, Jr., et al.,
Photographic Science and Engineering
, Vol. 20, No. 3, p. 97 (1976), a cationic dye is adsorbed onto the first layer and an anionic dye is adsorbed onto the second layer using electrostatic power.
Further, G. B. Bird, et al., in U.S. Pat. No. 3,622,316, a plurality of dyes are multilayer adsorbed onto silver halide and sensitized by Forster type excitation energy transfer.
However, even these above-described methods could not sufficiently improve the light absorption factor per unit surface area of a silver halide grain, therefore, a further technical development has been required.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for producing a silver halide emulsion having a high light absorption factor per unit area of a grain surface and a photographic material of high sensitivity using said emulsion.
The above object of the present invention has been achieved by the following (1), (2), (3), (4), (5), (6), (7) and (8).
(1) A silver halide photographic emulsion which contains silver halide grains having light absorption strength of 100 or more, wherein said silver halide grains are preferably spectrally sensitized.
(2) A silver halide photographic material which has at least one silver halide photographic emulsion layer containing the silver halide photographic emulsion described in (1) above.
(3) A silver halide photographic emulsion which contains silver halide grains having a spectral absorption maximum wavelength of 500 nm or less and light absorption strength of 60 or more and less than 100, wherein said silver halide grains are preferably spectrally sensitized.
(4) A silver halide photographic material which has at least one silver halide photographic emulsion layer containing the silver halide photographic emulsion described in (3) above.
(5) A silver halide photographic emulsion which contains at least one dye represented by the following formula (1) or (2) in an amount equivalent to the amount of 80% or more of the saturated coated amount and the total addition amount of sensitizing dyes is equivalent to the amount of 160% or more of the saturated coated amount:
wherein R
11
and R
12
each represents an alkyl group, at least one of R
11
and R
12
is an alkyl group represented by R
13
, where R
14
represents a single bond or a divalent linking group and Y
11
represents an aryl group or a heterocyclic aromatic group, and neither R
11
nor R
12
has an anionic substituent; Z
11
and Z
12
, which may be the same or different, each represents a 5- or 6-membered nitrogen-containing heterocyclic nucleus-forming atomic group; L
11
, L
12
, L
13
, L
14
, L
15
, L
16
and L
17
each represents a methine group; p
11
and p
12
each represents 0 or 1, n
11
represents 0, 1, 2 or 3; X
11
represents a counter ion for balancing a charge; and m
11
represents a number of from 0 to 8 necessary for neutralizing a charge in the molecule;
wherein R
21
and R
22
each represents an alkyl group, at least one of R
21
and R
22
is an alkyl group represented by R
23
, where R
24
represents a single bond or a divalent linking group and Y
21
represents an aryl group or a heterocyclic aromatic group, and both R
21
and R
22
have an anionic substituent; Z
21
and Z
22
, which may be the same or different, each represents a 5- or 6-membered nitrogen-containing heterocyclic nucleus-forming atomic group; L
21
, L
22
, L
23
, L
21
, L
25
, L
26
, and L
27
each represents a methine group; p
21
and p
22
each represents 0 or 1, n
21
represents 0, 1, 2 or 3; X
21
represents a counter ion for balancing a charge; and m
21
represents a number of from 0 to 8 necessary for neutralizing a charge in the molecule.
(6) A silver halide photographic material which has at least one silver halide photographic emulsion layer containing the silver halide photographic emulsion described in (5) above.
(7) A silver halide photographic emulsion which contains at least one dye represented by formula (1) and at least one dye represented by formula (2) described in (5) above.
(8) A silver halide photographic material which has at least one silver halide photographic emulsion layer containing the silver halide photographic emulsion described in (7) above.
A sensitizing dye can be multilayer adsorbed onto the surface of a silver halide grain according to the above method, and light absorption strength by a sensitizing dye per unit area of a silver halide grain surface can be made 100 or more, only when a grain has a spectral absorption maximum wavelength of 500 nm or less, light absorption strength of 60 or more. “Light absorption strength” in the above (1) and (3) means the light absorption strength per unit surface area by a sensitizing dye except for absorption by a silver halide grain. “The light absorption strength per unit surface area by a sensitizing dye” used herein is defined as the value obtained by integrating optical density Log (I
o
/(I
o
−I)) to wave number (cm
−1
), taking the light amount incident on the unit surface area of a grain as I
0
and the light amount absorbed by the sensitizing dye at said surface as I, and the integrated range is from 5,000 cm
−1
to 35,000 cm
−1
.
When a silver halide photographic emulsion contains silver halide grains having light absorption strength of 100 or more (or light absorption strength of 60 or more when the grains have spectral absorption maximum wavelength of 500 nm or less), it is preferred that ½ or more of the entire amount of silver halide grains contained in the emulsion be silver halide grains havin
Kobayashi Katsumi
Yamashita Katsuhiro
Chea Thorl
Fuji Photo Film Co. , Ltd.
LandOfFree
Silver halide photographic emulsion and silver halide... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silver halide photographic emulsion and silver halide..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silver halide photographic emulsion and silver halide... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3068059