Display device
A display device includes: a substrate; a display element on the substrate; a capping layer on the display element; an optical layer on the capping layer, and including: a first optical layer on the display element; and a second optical layer on the first optical layer; and a thin film encapsulation layer on the optical layer, and including: a first inorganic encapsulation layer on the second optical layer; an auxiliary layer on the first inorganic encapsulation layer; an organic encapsulation layer on the auxiliary layer; and a second inorganic encapsulation layer on the organic encapsulation layer. A refractive index of the second optical layer is smaller than a refractive index of the capping layer, and a refractive index of the first optical layer is between the refractive index of the second optical layer and the refractive index of the capping layer.
1. A display device comprising:
a substrate;
a display element on the substrate;
a capping layer on the display element;
an optical layer on the capping layer, and comprising:
a first optical layer on the display element; and
a second optical layer on the first optical layer; and
a thin film encapsulation layer on the optical layer, and comprising:
a first inorganic encapsulation layer on the second optical layer;
an auxiliary layer on the first inorganic encapsulation layer;
an organic encapsulation layer on the auxiliary layer; and
a second inorganic encapsulation layer on the organic encapsulation layer,
wherein a refractive index of the second optical layer is smaller than a refractive index of the capping layer, and
wherein a refractive index of the first optical layer is between the refractive index of the second optical layer and the refractive index of the capping layer.
2. The display device of claim 1 , wherein the refractive index of the first optical layer is in a range from 1.62 to 1.89, and a thickness of the first optical layer is in a range from 20 nm to 60 nm.
3. The display device of claim 2 , wherein the refractive index of the second optical layer is in a range from 1.45 to 1.62, and a thickness of the second optical layer is in a range from 40 nm to 100 nm.
4. The display device of claim 1 , wherein the refractive index of the capping layer is in a range from 1.6 to 2.3, and a thickness of the capping layer is in a range from 30 nm to 120 nm.
5. The display device of claim 1 , wherein a thickness of the auxiliary layer is in a range from 30 nm to 100 nm, and a thickness of the first inorganic encapsulation layer is in a range from 400 nm to 2200 nm.
6. The display device of claim 5 , wherein:
the auxiliary layer is interposed between the first inorganic encapsulation layer and the organic encapsulation layer,
a refractive index of the first inorganic encapsulation layer is greater than a refractive index of the auxiliary layer, and
the refractive index of the auxiliary layer is between the refractive index of the first inorganic encapsulation layer and a refractive index of the organic encapsulation layer.
7. The display device of claim 6 , wherein the refractive index of the auxiliary layer satisfies:
min( n 1, n 2)+| n 2− n 1|×0.25< n 3<min( n 1, n 2)+| n 2− n 1|×0.75,
where n3 represents the refractive index of the auxiliary layer, n1 represents the refractive index of the first inorganic encapsulation layer, n2 represents the refractive index of the organic encapsulation layer, min(n1, n2) represents a minimum value of n1 or n2, and |n2−n1| represents an absolute value of a difference between n2 and n1.
8. The display device of claim 1 , wherein each of the first inorganic encapsulation layer and the auxiliary layer comprises an inorganic insulating material.
9. The display device of claim 1 , further comprising:
a lower layer interposed between the auxiliary layer and the organic encapsulation layer.
10. The display device of claim 9 , wherein:
a refractive index of the auxiliary layer is greater than a refractive index of the organic encapsulation layer, and
a refractive index of the lower layer is between the refractive index of the auxiliary layer and the refractive index of the organic encapsulation layer.
11. The display device of claim 10 , wherein the refractive index of the auxiliary layer satisfies:
min( n 1, n 2)+| n 2− n 1|×0.25< n 3<min( n 1, n 2)+| n 2− n 1|×0.75,
where n3 represents the refractive index of the auxiliary layer, n1 represents a refractive index of the first inorganic encapsulation layer, n2 represents the refractive index of the lower layer, min(n1, n2) represents a minimum value of n1 or n2, and |n2−n1| represents an absolute value of a difference between n2 and n1.
12. The display device of claim 10 , wherein:
the refractive index of the lower layer is 0.05 less than the refractive index of the organic encapsulation layer, and
the lower layer comprises an inorganic insulating material.
13. The display device of claim 12 , wherein:
the lower layer and the auxiliary layer comprises an inorganic insulating material comprising a silicon element, a nitrogen element, and an oxygen element, and
an oxygen content of the lower layer is greater than an oxygen content of the auxiliary layer.
14. The display device of claim 1 , wherein the first inorganic encapsulation layer comprises a plurality of stacked films.
15. A display device comprising:
a substrate;
organic light emitting diodes on the substrate;
a capping layer on the organic light emitting diodes;
an optical layer on the capping layer, and comprising:
a first optical layer on the organic light emitting diodes; and
a second optical layer on the first optical layer; and
a thin film encapsulation layer on the optical layer to encapsulate the organic light emitting diodes, and comprising:
a first inorganic encapsulation layer on the second optical layer;
an auxiliary layer on the first inorganic encapsulation layer;
an organic encapsulation layer on the auxiliary layer; and
a second inorganic encapsulation layer on the organic encapsulation layer,
wherein a refractive index of the second optical layer is smaller than a refractive index of the capping layer, and
wherein a refractive index of the first optical layer is between the refractive index of the second optical layer and the refractive index of the capping layer.
16. The display device of claim 15 , wherein:
the refractive index of the first optical layer is in a range from 1.62 to 1.89,
a thickness of the first optical layer is in a range from 20 nm to 60 nm,
the refractive index of the second optical layer is in a range from 1.45 to 1.62, and
a thickness of the second optical layer is in a range from 40 nm to 100 nm.
17. The display device of claim 16 , wherein:
the refractive index of the capping layer is in a range from 1.6 to 2.3, and
a thickness of the capping layer is in a range from 30 nm to 120 nm.
18. The display device of claim 15 , wherein:
a thickness of the auxiliary layer is in a range from 30 nm to 100 nm, and
a thickness of the first inorganic encapsulation layer is in a range from 400 nm to 2200 nm.
19. The display device of claim 18 , wherein:
the auxiliary layer is interposed between the first inorganic encapsulation layer and the organic encapsulation layer,
a refractive index of the first inorganic encapsulation layer is greater than a refractive index of the auxiliary layer,
the refractive index of the auxiliary layer is between the refractive index of the first inorganic encapsulation layer and a refractive index of the organic encapsulation layer, and
the refractive index of the auxiliary layer satisfies:
min( n 1, n 2)+| n 2− n 1|×0.25< n 3<min( n 1, n 2)+| n 2− n 1|×0.75,
where n3 represents the refractive index of the auxiliary layer, n1 represents the refractive index of the first inorganic encapsulation layer, n2 represents the refractive index of the organic encapsulation layer, min(n1, n2) represents a minimum value of n1 or n2, and |n2−n1| represents an absolute value of a difference between n2 and n1.
20. The display device of claim 15 , wherein each of the first inorganic encapsulation layer and the auxiliary layer comprises an inorganic insulating material.