Organic light emitting display device
An organic light emitting display device is provided to avoid color change due to a viewing direction. The organic light emitting display includes a light compensation layer having a refractive index different than that of an insulating layer. The organic light emitting display may be disposed at the side to which light emitted from an organic light emitting layer is entered to change the path and phase of light, thereby coinciding cavity peak phases for each wavelength of white light emitted from an organic light emitting unit.
1. An organic light emitting display device, comprising:
a substrate having a plurality of R, G, B pixels;
a thin-film transistor at each of the R, G, B pixels;
an insulating layer on the thin-film transistor having a first refractive index;
a light compensation layer on the insulating layer having a second refractive index different than the first refractive index;
a plurality of pixel electrodes on the light compensation layer at each one of the R, G, B pixels;
a light emitting unit on the respective pixel electrodes to emit light; and
common electrode on the organic light emitting units,
wherein the light compensation layer, the pixel electrode, and the organic light emitting unit in each pixel have the following relation:
∑
i
n
i
0
d
i
0
λ
b
+
n
a
d
a
λ
b
+
∑
j
n
j
w
d
j
w
λ
b
=
1.7
∼
2.5
where d 0 , d a , d w are thicknesses of the light compensation layer, pixel electrode and organic light emitting unit, respectively, n 0 , n a , n w are refractive indices of the light compensation layer, pixel electrode and organic light emitting unit, respectively, and λ b is the peak wavelength of blue-light emitted from the organic light emitting unit.
2. The organic light emitting display device of claim 1 , wherein the organic light emitting unit is a white organic emitting unit for emitting white light.
3. The organic light emitting display device of claim 2 , further comprising a R,G,B color filter layers formed respectively at each pixel of R,G,B pixels.
4. The organic light emitting display device of claim 1 , wherein the organic light emitting unit comprises;
a plurality of organic light emitting layers for emitting the light; and
at least one charge generation layer between the organic light emitting layers.
5. The organic light emitting display device of claim 4 , wherein the charge generation layer includes n-type charge generation layer for generating n-type charges and p-type charge generation layer for generating p-type charges.
6. The organic light emitting display device of claim 4 , wherein the organic light emitting unit further comprises:
an electron injection layer for injecting electrons into the organic light emitting layer;
an electron transport layer for transporting electrons injected through the electron injection layer to the organic light emitting layer;
a hole injection layer for injecting holes into the organic light emitting layer; and
a hole transport layer for transporting holes injected through the hole injection layer.
7. The organic light emitting display device of claim 1 , wherein each pixel electrode is an anode and the common electrode is a cathode.
8. The organic light emitting display device of claim 1 , wherein the pixel electrodes include a transparent conductive material and the cathode includes a metal.
9. The organic light emitting display device of claim 1 , wherein the insulating layer includes an organic insulating material.
10. The organic light emitting display device of claim 1 , wherein the light compensation layer includes a material selected from the group consisting an organic insulating material, an inorganic insulating material, and an organic metal compound.
11. The organic light emitting display device of claim 1 , wherein the light compensation layer is single layer or multi layers.
12. The organic light emitting display device of claim 1 , wherein a total thickness of the pixel electrode, light compensation layer and organic light emitting unit is 5000-6000 Å when the maximum wavelength intensity of white light emitted from the organic light emitting unit is 440-470 nm or 550-580 nm.
13. The organic light emitting display device of claim 12 , wherein the organic light emitting unit is formed with a thickness of 1000-3000 Å, and the pixel electrodes is formed with a thickness of 300-700 Å, and the organic light emitting unit is formed with a thickness of 2000-4000 Å when the maximum wavelength intensity of white light emitted from the organic light emitting unit is 440-470 nm or 550-580 nm.
14. The organic light emitting display device of claim 1 , further comprising a plurality of thin-film transistors (TFTs) formed on the substrate and a TFT covering insulating layer formed on the substrate to cover the TFTs.
15. The organic light emitting display device of claim 1 , further comprising a W pixel configured to output white light emitted from the organic light emitting unit.