Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
1999-08-18
2003-04-22
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S917000, C428S704000, C313S504000, C313S506000
Reexamination Certificate
active
06551723
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a light-emitting element (e.g., organic electroluminescence (EL) element) material, which can convert electric energy to light to emit light and a light-emitting (luminescent) element comprising such a light-emitting element material. More particularly, the present invention relates to a light-emitting element which can be used in the art of display element, display, back light, electrophotography, illuminant, sign-board, interior, etc.
BACKGROUND OF THE INVENTION
The research and development of various display elements are now under way. Among these display elements, organic EL elements can emit light having a high luminescence at a low voltage and thus have been considered to be favorable display elements. For example, an EL element having an organic thin film formed by evaporation of an organic compound has been known (Applied Physics Letters, vol. 51, page 913, 1987). The organic EL element proposed has a laminated structure comprising an electron transporting material and a positive hole transporting material and hence exhibits drastically improved light-emitting properties as compared with the conventional single-layer type elements.
As a means for enhancing the percent emission of the foregoing laminated EL elements there has been known a process involving doping with a fluorescent dye. For example, an organic EL element doped with a coumarin dye described in “Journal of Applied Physics”, vol. 65, page 3,610, 1989 exhibits a drastically enhanced percent emission as compared with elements free of the dye. The organic EL element proposed can emit light having a desired wavelength by changing the kind of the fluorescent compound used. However, there are few compounds which can emit blue light at a high efficiency and exhibits an excellent durability.
As blue light-emitting materials for organic EL elements there have been disclosed condensed polycyclic aromatic compounds such as anthracene, pyrene and perylene (as disclosed in J. Chem. Phys., 44, 2902 (1966), Thin. Solid. Films, 99, 171 (1982)), tetraphenylbutadiene compounds (as disclosed in JP-A-59-194393 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”)), distyrylbenzene compounds (as disclosed in EP 4,672,265, EP 3,198,881, EP 3,735,582, U.S. Pat. Nos. 4,672,265, 4,725,531, 4,734,338, 4,741,976, 4,776,320, JP-A-61-37890, JP-A-1-245087, JP-A-2-247277, JP-A-2-247278, JP-A-2-209988, JP-A-3-33184, JP-A-3-84089, JP-A-3-231970, JP-A-4-117485, JP-A-4-275268, JP-A-5-17765, JP-A-5-140145), stilbene compounds (as disclosed in JP-A-2-235983, JP-A-3-47890, etc.), polyphenyl compounds (as disclosed in JP-A-3-33183), polycarbonate compounds having aromatic tertiary amine skeleton as a repeating unit (as disclosed in JP-A-5-247459), metal complexes having tropolone skeleton (as disclosed in JP-A-9-157642), and metal complexes having 2-(o-hydroxyphenyl)-benzoxazole derivative or 2-(o-hydroxyphenyl)-benzthiazole derivative as a ligand (as disclosed in JP-A-7-133483, JP-A-8-113576, JP-A-8-301877, JP-A-8-306489). However, these compounds are disadvantageous in that they exhibit a low percent emission or a deteriorated durability or color purity. Thus, these compounds cannot be put into practical use.
As electron transporting materials for organic EL elements there have been used 1, 3, 4-oxadiazole derivatives, tris (8-hydroxyquinolinate) aluminum, etc. The former material is disadvantageous in that it operates at a high driving voltage and exhibits a deteriorated durability. The latter material is disadvantageous in that it can hardly act as an electron transporting material for emission of blue light. It has thus been desired to develop an electron transporting material effective for emission of blue light.
On the other hand, an organic EL element which realizes emission of light having a high luminescence is an element having a laminate of vacuum-evaporated organic materials. Such an organic EL element is preferably prepared by coating process from the standpoint of simplification of production process, workability, increase of surface area of element, etc. However, elements prepared by the conventional coating process are inferior to elements prepared by evaporation process in luminescence and percent emission. Thus, it has been desired to enhance the luminescence and percent emission of these elements.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an organic EL element material which can emit light having a high color purity at a low driving voltage, a high luminescence and a high efficiency and exhibits an excellent stability in repeated use.
The foregoing object of the present invention will become more apparent from the following detailed description and examples.
The foregoing object of the present invention can be accomplished by the following constitutions:
(1) An organic electroluminescence element material which is a heterocyclic compound in which a 5- or 6-membered ring is condensed with a 5- to 7-membered ring.
(2) An organic electroluminescence element material which is a heterocyclic compound in which a 5-membered ring is condensed with a 5-membered ring.
(3) An organic electroluminescence element material which is a heterocyclic compound in which a 5-membered ring is condensed with a 6-membered ring.
(4) An organic electroluminescence element material which is a nitrogen-containing heterocyclic compound in which 5-membered ring is condensed with a 5-membered ring.
(5) An organic electroluminescence element material which is a nitrogen-containing heterocyclic compound in which a 5-membered ring is condensed with a 6-membered ring.
(6) An organic electroluminescence element material which is a nitrogen-containing heterocyclic compound in which a 5-membered ring is condensed with a 5-membered ring, and the nitrogen-containing heterocyclic compound has a nitrogen atom at the condensation position.
(7) An organic electroluminescence element material which is a nitrogen-containing heterocyclic compound in which a 5-membered ring is condensed with a 6-membered ring, and the nitrogen-containing heterocyclic compound has a nitrogen atom at the condensation position.
(8) An organic electroluminescence element material which is a compound represented by the following formula (I):
wherein R
11
, R
12
and R
13
each independently represents a hydrogen atom or substituent; and Z
1
represents an atomic group required to form a 5- or 6-membered ring.
(9) An organic electroluminescence element material which is a compound represented by the following formula (II):
wherein R
21
and R
22
each independently represents a hydrogen atom or substituent; and Z
2
represents an atomic group required to form a 5- or 6-membered ring.
(10) An organic electroluminescence element material which is a compound represented by the following formula (III):
wherein R
31
and R
32
each independently represents a hydrogen atom or substituent; and Z
3
represents an atomic group required to form a 5- or 6-membered ring.
(11) An organic electroluminescence element material which is a compound represented by the following formula (IV):
wherein R
41
and R
42
each independently represents a hydrogen atom or substituent; and Z
4
represents an atomic group required to form a 5- or 6-membered ring.
(12) An organic electroluminescence element material which is a compound represented by the following formula (V):
wherein R
51
represents a hydrogen atom or substituent; and Z
5
represents an atomic group required to form a 5- or 6-membered ring.
(13) An organic electroluminescence element material
which is a compound represented by the following formula (VI):
wherein R
61
represents a hydrogen atom or substituent; and Z
6
represents an atomic group required to form a 5- or 6-membered ring.
(14) An organic electroluminescence element material which is a compound represented by the following formula (VII):
wherein R
71
represents a hydrogen atom or substituent; and Z
7
rep
Igarashi Tatsuya
Okada Hisashi
Taguchi Toshiki
Fuji Photo Film Co. , Ltd.
Sughrue & Mion, PLLC
Xu Ling
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