Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
1999-03-23
2003-10-07
Yamnitzky, Marie (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S917000, C313S504000, C313S506000
Reexamination Certificate
active
06630253
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a red-color luminescent organic electroluminescence device that can be used for a planar light source and a display device.
2. Description of Related Art
Electroluminescence devices are expected to be used for a self-emission type planar display device. Among electroluminescence devices, there are organic electroluminescence devices using an organic substance which will hereinafter be referred to as organic EL devices. These are different from an inorganic electroluminescence device which will hereinafter be referred to as an inorganic EL device in that there is no need for an alternating current driving and a high voltage, and a variety of organic compounds makes it easy to realize multi-color displays, for which reason the organic EL device is expected to be applied to a color display and a development thereof is active.
If the organic EL device is applied to a full color display, it is required to obtain three primary colors, red, green and blue. Many examples of green emission have been reported. For example, a green color device using 8-quinolinol aluminum complex has been reported in
Applied Physics Letters
, vol. 51, p. 193, 1987. A device using a diarylamine derivative is disclosed in Japanese laid-open patent publication No. 8-53397.
Many blue color luminescent devices have been reported. A blue color luminescent device using a stilbene based compound is disclosed in Japanese laid-open patent publication No. 5-295359. A blue color luminescent device using a triarylamine derivative is disclosed in Japanese laid-open patent publication No. 7-53955. A blue color luminescent device using a triarylamine derivative is disclosed in Japanese laid-open patent publication No. 7-53955. A blue color luminescent device using a triaryldiamine derivative is disclosed in Japanese laid-open patent publication No. 8-48656. A blue color luminescent device using a styrylbiphenyl compound is disclosed in Japanese laid-open patent publication No. 6-132080.
In Japanese laid-open patent publication No. 3-152897, it is disclosed that a red color luminescent organic EL device obtains a red-color luminescence by wavelength conversion of the blue color luminescence in a luminescent layer. In Japanese laid-open patent publications Nos. 7-272854, 7-288184, and 8-286033, it is disclosed that a red color fluorescent coloring matter is doped into a luminescent layer to obtain a red-color luminescence.
However, the above red-color luminescent organic EL device is insufficient in both brightness and color purity. In the above-mentioned Japanese laid-open patent publications Nos. 7-272854, 7-288184, and 8-286033, there is disclosed an organic EL device using a red-color fluorescent coloring matter along for a luminescent layer. Notwithstanding, a sufficient color purity for red-color luminescence is not obtained. It is therefore required to further improve the color purity for red-color luminescence.
It is significant that, prior to the present invention, no red-color luminescent organic EL device could be obtained which has sufficiently practicable characteristics or properties.
SUMMARY OF THE INVENTION
The present invention was made in this viewpoint and an object thereof is to provide a red-color luminescent organic EL device having high luminescent brightness and high color purity as well as being stable in use.
An organic electroluminescence device having a cathode, an anode, and at least a single organic thin film including a luminescent layer between the cathode and anode, is characterized in that at least one layer of said organic thin films contains a bis-2,5-(2-benzazoyl) hydroquinone compound represented by a general formula (1):
where each of R
1
-R
8
independently represents hydrogen atom, halogen atom, hydroxyl group, substituted or unsubstituted amino group, nitro group, cyano group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic complex ring group, substituted or unsubstituted aralkyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkoxy carbonyl group, or carboxyl group, and any two of R
1
-R
8
may form a ring and “X” represents “NH”, “O” and “S”.
It is possible that said luminescent layer comprises a mixture of the bis-2,5-(2-benzazoyl) hydroquinone compound represented by the general formula (1) and an aromatic amine compound represented by a general formula (2):
where each of Ar
1
-Ar
3
independently represents substituted or unsubstituted aromatic hydrocarbon group, or substituted or unsubstituted aromatic complex ring group, and any two of substituents possessed by Ar
1
-Ar
3
may form a ring.
It is also possible that said luminescent layer comprises a mixture of the bis-2,5-(2-benzazoyl) hydroquinone compound represented by the general formula (1) and an aromatic diamine compound represented by a general formula (3):
where each of Ar
1
-Ar
4
independently represents substituted or unsubstituted aromatic hydrocarbon group, or substituted or unsubstituted aromatic complex ring group, and “Y” represents substituted or unsubstituted arylene group, any two of substituents possessed by Ar
1
-Ar
4
may form a ring.
It is also possible that said luminescent layer comprises a mixture of the bis-2,5-(2-benzazoyl) hydroquinone compound represented by the general formula (1) and an aromatic triamine compound represented by a general formula (4):
where each of Ar
1
-Ar
6
independently represents substituted or unsubstituted aromatic hydrocarbon group, or substituted or unsubstituted aromatic complex ring group, and “Z” represents trivalent substituted or substituted aromatic hydrocarbon group or substituted or unsubstituted aromatic complex ring group, any two of substituents possessed by Ar
1
-Ar
6
may form a ring.
It is also possible that said luminescent layer comprises a mixture of the bis-2,5-(2-benzazoyl) hydroquinone compound represented by the general formula (1) and an oxime metal complex compound represented by general formula (5):
where each of R
9
-R
14
independently represents hydrogen atom, halogen atom, hydroxyl group, substituted or unsubstituted amino group, nitro group, cyano group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic complex ring group, substituted or unsubstituted aralkyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkoxy carbonyl group, or carboxyl group, any two of substituents possessed by R
9
-R
14
may form a ring, and “L1” represents substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic complex ring group, or substituted or unsubstituted aralkyl group, and “n” is the integer in the range of 1-3, and “m” is the integer in the range of 0-2, and “M” represents a metal ion of (n+m)-valence.
It is also possible that said luminescent layer comprises a mixture of the bis-2,5-(2-benzazoyl) hydroquinone compound represented by the general formula (1) and an oxime metal complex compound represented by a general formula (6):
where each of R
15
-R
26
independently represents hydrogen atom, halogen atom, hydroxyl group, substituted or unsubstituted amino group, nitro group, cyano group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic complex ring group, substituted or
Mori Kenji
Tanaka Taizou
Toguchi Satoru
NEC Corporation
Yamnitzky Marie
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