EL display device utilizing light-emitting organic compounds and method for forming the same
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.
Claims18
A digital camera comprising:
- a main body;
- a display portion;
- an image receiving portion;
- and
- an operation switch,
- the display portion comprising:
- a plurality of pixels formed over a substrate, each of the plurality of pixels comprising a light-emitting element,
- wherein the light-emitting element comprises an EL layer including a light-emitting organic compound, and
- wherein the EL layer includes ionic impurities at the concentration of 0.1 ppm or lower.
A digital camera comprising:
- a main body;
- a display portion;
- an image receiving portion;
- and
- an operation switch,
- the display portion comprising:
- a plurality of pixels formed over a substrate, each of the plurality of pixels comprising a light-emitting element,
- wherein the light-emitting element comprises an EL layer including a light-emitting organic compound, and
- wherein the EL layer includes ionic impurities at the concentration of 0.01 ppm or lower.
A digital camera comprising:
- a main body;
- a display portion;
- an image receiving portion;
- and
- an operation switch,
- the display portion comprising:
- a plurality of pixels formed over a glass substrate, each of the plurality of pixels comprising a light-emitting element,
- wherein the light-emitting element comprises an EL layer including a light-emitting organic compound, and
- wherein the EL layer includes ionic impurities at the concentration of 0.1 ppm or lower and has a volume resistivity of 3×1010 Ωcm or larger.
A digital camera comprising:
- a main body;
- a display portion;
- an image receiving portion;
- and
- an operation switch,
- the display portion comprising:
- a plurality of pixels formed over a glass substrate, each of the plurality of pixels comprising a light-emitting element,
- wherein the light-emitting element comprises an EL layer including a light-emitting organic compound, and
- wherein the EL layer includes ionic impurities at the concentration of 0.01 ppm or lower and has a volume resistivity of 3×1010 Ωcm or larger.
A digital camera comprising:
- a main body;
- a display portion;
- an image receiving portion;
- and
- an operation switch,
- the display portion comprising:
- a plurality of pixels formed over a substrate, each of the plurality of pixels comprising a light-emitting element,
- wherein the light-emitting element comprises an EL layer including a light-emitting organic compound, and
- wherein the EL layer includes ionic impurities at the concentration of 0.1 ppm or lower and has a volume resistivity of 1×1011 to 1×1012 Ωcm.
A digital camera comprising:
- a main body;
- a display portion;
- an image receiving portion;
- and
- an operation switch,
- the display portion comprising:
- a plurality of pixels formed over a substrate, each of the plurality of pixels comprising a light-emitting element,
- wherein the light-emitting element comprises an EL layer including a light-emitting organic compound, and
- wherein the EL layer includes ionic impurities at the concentration of 0.01 ppm or lower and has a volume resistivity of 1×1011 to 1×1012 Ωcm.
Dependencies are inferred from the claim text.