Organic light emitting display device having a resonance structure of proper internal reflection by including a light extraction reduction preventing layer
In an organic light emitting display device according to an embodiment of the present disclosure, a light extraction reduction preventing layer is disposed between a display unit disposed on a substrate and an encapsulation layer for protecting the display unit, and as a result, light emission efficiency may be improved by reducing an amount of light dissipating while light generated from an emission layer of the display unit is extracted to the outside.
1. An organic light emitting display device, comprising:
a substrate;
a first electrode disposed on the substrate;
an emission layer disposed on the first electrode;
a second electrode disposed on the emission layer;
an inorganic layer arranged on the second electrode;
a first layer disposed on the inorganic layer; and
a thin film encapsulation layer disposed on the first layer,
wherein the thin film encapsulation layer has a structure in which a plurality of inorganic layers and a plurality of organic layers are alternately laminated,
wherein a refractive index of the first layer is lower than a refractive index of the inorganic layer arranged on the second electrode and lower than a refractive index of the thin film encapsulation layer,
wherein, in a cross-sectional view, the first layer is contacted by the thin film encapsulation layer and the inorganic layer arranged on the second electrode,
wherein, in the cross-sectional view, a portion of the inorganic layer arranged on the second electrode contacts a portion of the thin film encapsulation layer,
wherein the thin film encapsulation layer directly surrounds and contacts side and top portions of the first layer that are not directly facing the inorganic layer,
wherein ends of each of the plurality of organic layers and each of the plurality of inorganic layers of the thin film encapsulation layer and the inorganic layer arranged on the second electrode contact the substrate, and
wherein the first layer is spaced apart from the substrate.
2. The organic light emitting display device of claim 1 , wherein a thickness of each of the plurality of organic layers of the thin film encapsulation layer is greater than a thickness of each of the plurality of inorganic layers of the thin film encapsulation layer.
3. The organic light emitting display device of claim 1 , wherein a refractive index of the thin film encapsulation layer is in a range of from about 1.5 to about 2.0.
4. The organic light emitting display device of claim 1 , wherein a refractive index of the first layer is in a range of 1.1 or more to less than 1.5.
5. The organic light emitting display device of claim 4 , wherein the first layer comprises at least one of CaF 2 , NaF, Na 3 AlF 6 , SiOx, AlF 3 , LiF, MgF 2 , and IF 3 .
6. The organic light emitting display device of claim 1 , wherein a thickness of the first layer is from about 20 nm to about 200 nm.
7. The organic light emitting display device of claim 1 , wherein a first major surface of the first layer is in contact with a major surface of the thin film encapsulation layer across the major surface of the thin film encapsulation layer at locations corresponding to an optical path of light produced by the emission layer and propagating to an outside of the display device, and a second and opposite major surface of the first layer is in contact with a major surface of the inorganic layer arranged on the second electrode across the major surface of the inorganic layer arranged on the second electrode at locations corresponding to an optical path of light produced by the emission layer and propagating to an outside of the display device.
8. The organic light emitting display device of claim 1 , wherein the inorganic layer arranged on the second electrode is comprised of a same material and is produced by a same process as the inorganic layers of the thin film encapsulation layer.
9. The organic light emitting display device of claim 1 , wherein:
the inorganic layer arranged on the second electrode is an ultraviolet blocking layer; and
each of the plurality of organic layers of the thin film encapsulation layer is produced by irradiating an organic precursor or monomer coating with ultraviolet radiation.
10. The organic light emitting display device of claim 1 , wherein the at least one of the plurality of organic layers of the thin film encapsulation layer is arranged directly on the first layer.
11. An organic light emitting display device, comprising:
a substrate;
a first electrode disposed on the substrate;
an emission layer disposed on the first electrode;
a second electrode disposed on the emission layer;
an inorganic layer arranged on the second electrode;
a first layer arranged on the inorganic layer arranged on the second electrode; and
a thin film encapsulation layer disposed on the first layer,
wherein the thin film encapsulation layer has a structure in which a plurality of inorganic layers and a plurality of organic layers are alternately laminated,
wherein a refractive index of the first layer is lower than a refractive index of the inorganic layer arranged on the second electrode and lower than a refractive index of the thin film encapsulation layer,
wherein in a cross-sectional view, the first layer is encapsulated between the thin film encapsulation layer and the inorganic layer arranged on the second electrode,
wherein, in the cross-sectional view, a portion of the inorganic layer arranged on the second electrode contacts a portion of the thin film encapsulation layer,
wherein the thin film encapsulation layer surrounds and contacts side and top portions of the first layer that are not directly facing the inorganic layer,
wherein ends of each of the plurality of organic layers and each of the plurality of inorganic layers of the thin film encapsulation layer and the inorganic layer arranged on the second electrode contact the substrate, and
wherein the first layer is spaced-apart from the substrate.
12. The organic light emitting display device of claim 11 , wherein a thickness of each of the plurality of organic layers of the thin film encapsulation layer is greater than a thickness of each of the plurality of inorganic layers of the thin film encapsulation layer.
13. The organic light emitting display device of claim 11 , wherein a refractive index of the thin film encapsulation layer is in a range of from about 1.5 to about 2.0.
14. The organic light emitting display device of claim 11 , wherein a refractive index of the first layer is in a range of 1.1 or more to less than 1.5.
15. The organic light emitting display device of claim 11 , wherein the first layer comprises at least one of CaF 2 , NaF, Na 3 AlF 6 , SiOx, AlF 3 , LiF, MgF 2 , and IF 3 .
16. The organic light emitting display device of claim 11 , wherein a thickness of the first layer is from about 20 nm to about 200 nm.
17. The organic light emitting display device of claim 11 , wherein the inorganic layer arranged on the second electrode is comprised of a same material and is produced by a same process as the inorganic layers of the thin film encapsulation layer.
18. The organic light emitting display device of claim 11 , wherein:
the inorganic layer arranged on the second electrode is an ultraviolet blocking layer; and
each of the plurality of organic layers of the thin film encapsulation layer is produced by irradiating an organic precursor or monomer coating with ultraviolet radiation.
19. An organic light emitting display device, comprising:
a substrate:
a first electrode disposed on the substrate;
a second electrode overlapping the first electrode:
an emission layer stacked between the first electrode and the second electrode:
an inorganic layer overlapping the second electrode;
a first layer spaced apart from the substrate and contacting the inorganic layer, a refractive index of the first layer being lower than a refractive index of the inorganic layer overlapping the second electrode; and
an encapsulation layer overlapping the first layer, a refractive index of the first layer being lower than a refractive index of the encapsulation layer,
wherein:
the encapsulation layer comprises a plurality of organic layers and a plurality of inorganic layers alternately stacked with one another;
ends of each of the plurality of organic layers and each of the plurality of inorganic layers of the thin film encapsulation layer and the inorganic layer overlapping the second electrode contact the substrate; and
the first layer is spaced-apart from the substrate.