ORGANIC LIGHT EMITTING DIODE DISPLAY
An organic light emitting diode (OLED) display includes a substrate, a first electrode disposed on the substrate, an organic emission layer disposed on the first electrode, a second electrode disposed on the organic emission layer, and a capping layer disposed on the second electrode, in which an optical thickness of the capping layer is in a range of about 1100 Å to about 1400 Å.
1 . An organic light emitting diode (OLED) display, comprising:
a substrate;
a first electrode disposed on the substrate;
an organic emission layer disposed on the first electrode;
a second electrode disposed on the organic emission layer; and
a capping layer disposed on the second electrode,
wherein an optical thickness of the capping layer is in a range of about 1100 Å to about 1400 Å.
2 . The OLED display of claim 1 , wherein a refractive index of the capping layer is in a range of about 1.6 to about 2.6.
3 . The OLED display of claim 2 , wherein a physical thickness of the capping layer is in a range of about 600 Å to about 730 Å when the refractive index of the capping layer is about 1.87.
4 . The OLED display of claim 1 , wherein the optical thickness is measured at a wavelength of about 550 nm.
5 . The OLED display of claim 1 , wherein the capping layer comprises an organic material or an inorganic material.
6 . The OLED display of claim 5 , wherein the capping layer comprises at least one of a triamine derivative, an arylenediamine derivative, CBP, and tris(8-hydroxyquinoline) aluminum (Alq 3 ).
7 . The OLED display of claim 1 , further comprising:
a first color pixel, a second color pixel, and a third color pixel,
wherein:
each of the first color pixel, the second color pixel, and the third color pixel comprises the first electrode, the organic emission layer, the second electrode, and the capping layer; and
the organic emission layer comprises:
a hole injection layer and a hole transporting layer disposed on the first electrode;
an emission layer disposed on the hole transporting layer, the emission layer comprising a host and a dopant; and
an electron transporting layer and an electron injection layer disposed on the emission layer.
8 . The OLED display of claim 7 , wherein the emission layer of the first color pixel comprises:
a first emission layer comprising the host; and
a second emission layer comprising the host and the dopant.
9 . The OLED display of claim 8 , wherein the first emission layer does not comprise the dopant.
10 . The OLED display of claim 9 , wherein the first color pixel is a green pixel.
11 . The OLED display of claim 8 , wherein the second emission layer is disposed on the first emission layer.
12 . The OLED display of claim 11 , wherein:
the first emission layer contacts the hole injection layer or the hole transporting layer; and
the second emission layer contacts the electron transporting layer or the electron injection layer.
13 . The OLED display of claim 8 , wherein the second emission layer is disposed between first emission layers.
14 . The OLED display of claim 13 , wherein the second emission layer is disposed in a center region of the emission layer.
15 . The OLED display of claim 13 , wherein:
the first emission layer disposed on the second emission layer contacts the hole injection layer or the hole transporting layer; and
the first emission layer disposed under the second emission layer contacts the electron transporting layer or the electron injection layer.
16 . An organic light emitting diode (OLED) display, comprising:
a substrate;
a first electrode disposed on the substrate;
an organic emission layer disposed on the first electrode;
a second electrode disposed on the organic emission layer; and
a capping layer disposed on the second electrode, the capping layer comprising a first capping layer and a second capping layer having different refractive indices from each other,
wherein:
an optical thickness of the first capping layer is in a range of about 60 Å to 210 Å; and
an optical thickness of the second capping layer is in a range of about 820 Å to about 1030 Å.
17 . The OLED display of claim 16 , wherein:
the second capping layer is disposed on the first capping layer; and
a refractive index of the second capping layer is higher than a refractive index of the first capping layer.
18 . The OLED display of claim 17 , wherein a difference between the refractive index of the first capping layer and the refractive index of the second capping layer is in a range of about 0.1 to about 1.4.
19 . The OLED display of claim 17 , wherein:
the refractive index of the first capping layer is in a range of about 1.2 to about 1.5; and
the refractive index of the second capping layer is in a range of about 1.6 to about 2.6.
20 . The OLED display of claim 19 , wherein a physical thickness of the first capping layer is in a range of about 50 Å to about 150 Å when the refractive index of the first capping layer is about 1.38.
21 . The OLED display of claim 19 , wherein a physical thickness of the second capping layer is in a range of about 400 Å to about 500 Å when the refractive index of the second capping layer is about 2.0.
22 . The OLED display of claim 16 , further comprising:
a first color pixel, a second color pixel, and a third color pixel,
wherein:
each of the first color pixel, the second color pixel, and the third color pixel comprises the first electrode, the organic emission layer, the second electrode, and the capping layer; and
the organic emission layer comprises:
a hole injection layer and a hole transporting layer disposed on the first electrode;
an emission layer disposed on the hole transporting layer, the emission layer comprising a host and a dopant; and
an electron transporting layer and an electron injection layer disposed on the emission layer.
23 . The OLED display of claim 22 , wherein:
the emission layer of the first color pixel comprises:
a first emission layer, the first emission layer comprising the host and not comprising the dopant; and
a second emission layer comprising the host and the dopant; and the first color pixel is a green pixel.