Light extraction member and organic light emitting diode including the same
A light extraction member includes a plurality of unit lenses arranged on one surface thereof. Each of the unit lenses comprises a combination of two or more kinds of conic lenses.
1. A light extraction member comprising a plurality of unit lenses arranged on one surface thereof,
wherein each of the unit lenses comprises a first conic lens forming a lower part of the unit lens and a second conic lens forming an upper part of the unit lens; and
wherein the first conic lens has a lens shape expressed as [Equation 1], and the second conic lens has a lens shape expressed as [Equation 2]:
y
=
H
1
-
x
2
/
r
1
1
+
1
-
(
1
+
k
1
)
(
1
/
r
1
)
2
x
2
[
Equation
1
]
where r 1 represents a curvature radius at a virtual vertex of the first conic lens, k 1 represents a conic constant of the first conic lens, and H 1 represents a height from the bottom surface of the first conic lens to the virtual vertex, and
y
=
H
2
-
x
2
/
r
2
1
+
1
-
(
1
+
k
2
)
(
1
/
r
2
)
2
x
2
+
y
0
[
Equation
2
]
where r 2 represents a curvature radius at the vertex of the second conic lens, k 2 represents the conic constant of the second conic lens, H 2 represents a height from the bottom surface of the second conic lens to the vertex, and y 0 represents a height from the bottom surface of the first conic lens to a position where the diameter of the bottom surface of the second conic lens is equalized to the diameter of the cross-section of the first conic lens.
2. The light extraction member of claim 1 , wherein the pitch between the unit lenses ranges from 20 to 500 μm.
3. The light extraction member of claim 1 , wherein the height of the unit lenses ranges from 10 to 100% of the pitch between the unit lenses.
4. The light extraction member of claim 1 , wherein the unit lenses are arranged in a honeycomb structure.
5. The light extraction member of claim 1 , wherein the diameter of the bottom surface of the first conic lens ranges from 80 to 116% of the pitch between the unit lenses.
6. The light extraction member of claim 1 , wherein the diameter of the bottom surface of the second conic lenses ranges from 40 to 80% of the diameter of the bottom surface of the first conic lens.
7. The light extraction member of claim 1 , wherein r 1 ranges from 0.1 to 200% of the diameter of the bottom surface of the first conic lens.
8. The light extraction member of claim 1 , wherein k 1 ranges from −25 to −1.2.
9. The light extraction member of claim 1 , wherein r 2 has a different value from r 1 .
10. The light extraction member of claim 9 , wherein r 2 ranges from 50 to 3000% of the diameter of the bottom surface of the second conic lens.
11. The light extraction member of claim 1 , wherein k 2 has a different value from k 1 .
12. The light extraction member of claim 11 , wherein k 2 ranges from −2.5 to 0.
13. An organic light emitting diode (OLED) comprising the light extraction member of claim 1 .