Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2000-03-22
2002-08-27
Yamnitzky, Marie (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S917000, C313S504000, C313S506000
Reexamination Certificate
active
06440586
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a compound suitable for use for a filter dye, a color conversion filter, a photographic material, a sensitizing dye, a dye for pulp-dyeing, a laser dye, a fluorescent medicine for a medical diagnosis, a luminous device, etc. Particularly, the present invention relates to a material for a luminous device for use in planar light sources and displays, and to a luminous device of high luminance. More specifically, the invention relates to the luminous material capable of emitting sharp green to red light of high luminance, high luminous efficiency and high color purity with low voltage application, and to a luminous device using the luminous material.
BACKGROUND OF THE INVENTION
Prospects of a luminous device in which organic materials are used are promising as a solid luminescent type inexpensive and large area full color display device and development has been tried variously. A luminous device generally comprises a pair of counter electrodes and a luminous layer interposed between the electrodes. When an electric field is impressed between the electrodes, electrons are injected from the cathode and positive holes are injected from the anode, and the electrons and positive holes are recombined in the luminous layer. A phenomenon of emitting energy as light when energy level is returned from conduction band to valence band is luminescence.
Luminous devices so far been used require high driving voltage and emission luminance and luminous efficiency are low, and characteristic deterioration is remarkable, so have not been put to practical use yet. An organic luminous device comprising lamination of thin layers containing an organic compound having high fluorescent quantum efficiency capable of emitting light with low voltage of 10 V or lower has been reported (
Applied Physics Letters
, Vol. 51, p. 913 (1987)) and attracting public attention in recent years. According to this technique, high luminance green light emission can be obtained by using a metal chelate complex as the electron-transporting layer, a fluorescent band layer as the luminous layer, and an amine compound as the positive hole-transporting layer, as a result, luminance has reached several 1,000 cd/m
2
with direct current voltage of 6 to 7 V. However, further improvement of luminance and development of luminous device of high luminous efficiency have been required in the light of a practical luminous device. Further, when taking into consideration the utilization of a luminous device as a full color display and a light source, it is necessary to get three primary colors or a white color in practical use. A device capable of emitting a desired color by doping a fluorescent dye is reported (
Journal of Applied Physics
, Vol. 65, p. 3610 (1989)). This technique is particularly effective for red luminescence in which extinction due to concentration is large and a fluorescent dye alone is used with difficulty as the luminous layer, and high color purity and high luminance have been attained in red luminescence. However, when a device doped with a dye is produced by deposition, there have been problems such that characteristics of devices are difficult to be reproduced from the aspect of its manufacturing process and that since the durability of the dye is low, the luminance is reduced or the color changes after being used for a long period of time. To cope with these problems, development of the material which functions as an electric charge-transporting material and a luminous material in one has been desired. However, with materials so far been developed, when a fluorescent dye is used in high concentration as an electric charge-transporting material, there have been problems that emission with high luminance is difficult as extinction due to concentration and that characteristics of devices are deteriorated due to agglomeration of the fluorescent dye with the lapse of time. Therefore, from the viewpoint of the simplification of producing step and the stability of performance of a device, a luminous material having good color purity and capable of using a dye alone as the luminous layer, in particular, a non-doping type luminous material capable of attaining good chromaticity and luminance even when a dye is used alone as the luminous layer has so far been desired.
On the other hand, luminous devices which have realized high luminance emission are laminated devices formed by vacuum deposition of organic materials, but from the viewpoint of simplification of producing step, processability, and realization of large area devices, it is desired to produce devices by a coating system. However, devices produced by a coating system so far been used are inferior to those produced by a vapor deposition system in luminance and luminous efficiency, therefore, high luminance and luminescence with high efficiency have been left as the problems to be solved. In addition, with devices produced by coating an organic low molecular weight compound dispersed in a polymer binder, uniform planar luminescence for a long period of time is difficult due to the agglomeration of the organic low molecular weight compound.
Further, in recent years, various materials having fluorescence have been used for a filter dye, a color conversion filter, a dye for a photographic material, a sensitizing dye, a dye for pulp-dyeing, a laser dye, a fluorescent medicine for a medical diagnosis, a material for a luminous device, etc., and demand for such materials has been increased. However, compounds having high fluorescent color purity and high fluorescent intensity are less, therefore, the development of a novel material has been desired.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide a material for a luminous device capable of emitting light with high luminance and high efficiency, excellent in stability at repeated use, and capable of uniform and planar emission with low voltage driving, and to provide a luminous device using the material.
A second object of the present invention is to provide a compound having high fluorescent intensity and high fluorescent color purity.
A third object of the present invention is to provide a luminous material capable of attaining emission with high luminance and high luminous efficiency even in the form of non-doping type, and to provide a luminous device using the material.
A fourth object of the present invention is to provide a material for a luminous device having high luminescent color purity, and to provide a luminous device using the material.
Other objects and effects of the present invention will become more apparent from the following description.
The present invention relates to the following compounds:
a compound represented by formula (I):
wherein R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
and R
8
each represents a hydrogen atom or a substituent; X represents O, S or N—R, wherein R represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group; Y represents O, S or CQ
1
(Q
2
), wherein Q
1
and Q
2
each represents a hydrogen atom or a substituent, at least either one of them represents an electron attractive group, and Q
1
and Q
2
may be linked to each other to form a ring; and Z is represented by the following formula (II):
wherein R
a
and R
b
each represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, and at least one combination of R
a
and R
b
, R
a
and R
1
, and R
b
and R
2
may be linked to each other to form a ring; M represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, a heterocyclic group or a cation;
a compound represented by formula (I-a):
wherein R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
and R
8
each represents a hydrogen atom or a substituent; X represents O, S or N—R, wherein R represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group; Ar
a
and Ar
b
each represents an aryl group or an aromatic heterocyclic group, and at least one combination of Ar
a
and A
Igarashi Tatsuya
Okada Hisashi
Yanagi Terukazu
Fuji Photo Film Co. , Ltd.
Yamnitzky Marie
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