Light-emitting EL display device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Toshimitsu Konuma, Mayumi Mizukami
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Abstract
By repeating a purification process of a light-emitting organic compound several times, a thin film made of the light-emitting organic compound to be used in an EL display device contains ionic impurities at the concentration of 0.1 ppm or lower and has a volume resistivity in the range of 3×1010 Ωcm or larger. By using such a thin film as a light-emitting layer in the EL device, a current caused by reasons other than the carrier recombination can be prevented from flowing through the thin film, and deterioration caused by unnecessary heat generation can be suppressed. Accordingly, it is possible to obtain an EL display device with high reliability.
Claims20
An EL display device having pixels each provided with an EL element, wherein the EL element includes a thin film comprising a light-emitting organic compound, and the thin film includes ionic impurities and has a volume resistivity of 3×1010 Ωcm or larger, and the concentration of the ionic impurities is 0.1 ppm or lower.
An EL display device having pixels each provided with a thin film transistor (TFT) and an EL element connected to the TFT, wherein the EL element includes a thin film comprising a light-emitting organic compound, and the thin film includes ionic impurities and has a volume resistivity of 3×1010 Ωcm or larger, and the concentration of the ionic impurities is 0.1 ppm or lower.
An EL display device having pixels each provided with an EL element, comprising:
- anodes arranged in stripes;
- cathodes arranged in stripes to be orthogonal to the anode;
- and
- a thin film made of a light-emitting organic compound provided between the anodes and the cathodes,
- wherein the thin film comprises ionic impurities and has a volume resistivity of 3×1010 Ωcm or larger, and
- wherein the concentration of the ionic impurities is 0.1 ppm or lower.
A method for fabricating an EL display device having pixels each provided with an EL element, comprising:
- forming a thin film comprising a light-emitting organic compound,
- wherein the thin film includes ionic impurities and has a volume resistivity of 3×1010 Ωcm or larger, and
- wherein the concentration of the ionic impurities is 0.1 ppm or lower.
An EL display device having pixels each provided with an EL element, wherein the EL element includes a thin film comprising a light-emitting organic compound, and the thin film includes ionic impurities at the concentration of 0.1 ppm or lower and has a volume resistivity of 1×1011 to 1×1012 Ωcm.
An EL display device having pixels each provided with a TFT and an EL element connected to the TFT, wherein the EL element includes a thin film comprising a light-emitting organic compound, and the thin film includes ionic impurities at the concentration of 0.1 ppm or lower and has a volume resistivity of 1×1011 to 1×1012 Ωcm.
An EL display device having pixels each provided with an EL element, comprising:
- anodes arranged in stripes;
- cathodes arranged in stripes to be orthogonal to the anode;
- and
- a thin film made of a light-emitting organic compound provided between the anodes and the cathodes,
- wherein the thin film comprises ionic impurities and has a volume resistivity of 1×1011 to 1×1012 Ωcm, and
- wherein the concentration of the ionic impurity is 0.1 ppm or lower
A method for fabricating an EL display device having pixels each provided with an EL element, comprising:
- forming a thin film comprising a light-emitting organic compound,
- wherein the thin film includes ionic impurities and has a volume resistivity of 1×1011 to 1×1012 Ωcm, and
- wherein the concentration of the ionic impurities is 0.1 ppm or lower.
Dependencies are inferred from the claim text.