Display device, organic light emitting display device, and head-mounted display device
A display device includes a substrate, a first display element which is disposed on the substrate, and a plurality of diffraction patterns which are disposed on a path of light emitted from the first display element and arranged along a direction with a first period. when a width of a cross section of one of the plurality of diffraction patterns is defined as a first length, the first period and the first length satisfy Inequality (1): 0.4≤ d 1/ DP 1≤1, (1) where DP 1 is the first period, and d 1 is the first length.
1. A display device comprising:
a substrate;
a pixel electrode on the substrate;
a display element emitting a light and disposed on the pixel electrode;
a common electrode on the display element;
an encapsulation layer on the common electrode;
an air between the display element and the encapsulation layer; and
a plurality of diffraction patterns on the encapsulation layer,
wherein:
the plurality of diffraction patterns includes a first diffraction pattern and a second diffraction pattern arranged along a first direction with a first period,
a width of a cross section of each of the first diffraction pattern and the second diffraction pattern is defined as a first length,
the first length and the first period satisfy Inequality (1):
0.4≤ d 1/ DP 1≤1, (1)
where DP 1 is the first period, and d 1 is the first length.
2. The display device of claim 1 , wherein the plurality of diffraction patterns further includes a third diffraction pattern, and
wherein the first diffraction pattern and the third diffraction pattern are arranged along a second direction crossing the first direction with a second period.
3. The display device of claim 1 , wherein the plurality of diffraction patterns are protruded from the encapsulation layer.
4. The display device of claim 1 , wherein the plurality of diffraction patterns are holes penetrating a diffraction pattern layer on the encapsulation layer.
5. The display device of claim 1 , wherein each of the plurality of diffraction patterns has a quadrilateral shape in a plan view,
wherein the first length is a diagonal of the first diffraction pattern.
6. The display device of claim 1 , wherein each of the plurality of diffraction patterns has a circle shape or an ellipse shape in a plan view.
7. The display device of claim 6 , wherein the first length is a diameter when each of the plurality of diffraction patterns has a circle shape in a plan view.
8. The display device of claim 1 , further comprising a protective layer on the diffraction patterns.
9. The display device of claim 1 , wherein the encapsulation layer is a glass.
10. The display device of claim 1 , wherein the encapsulation layer and the plurality of diffraction patterns comprise a same material.
11. The display device of claim 1 , wherein the plurality of diffraction patterns are arranged in a rectangular array in a plan view.
12. The display device of claim 1 , wherein each of the plurality of diffraction patterns has a first refractive index and the air has a second refractive index, wherein the first refractive index, the second refractive index, and a thickness of the first diffraction pattern satisfy Inequality (2):
( m *λ)−60 (nm)≤ A (nm)≤( m *λ)+60 (nm)
A≠Δn·t 1 (nm), (2)
where A is a value equal to or greater than (m*λ)−60 (nm) and equal to or less than (m*λ)+60 (nm), Δn=|n 1 −n 2 |, n 1 is the first refractive index, n 2 is the second refractive index, t 1 is the thickness of each of the plurality of diffraction patterns, λ is a wavelength of the light emitted from the display element, and m is an integer of 0 or more.
13. The display device of claim 1 , wherein the plurality of diffraction patterns are arranged in a hexagonal array in a plan view.
14. A display device comprising:
a substrate;
a pixel electrode on the substrate;
a display element emitting a light and disposed on the pixel electrode;
a common electrode on the display element;
an encapsulation layer on the common electrode;
an air between the display element and the encapsulation layer; and
a plurality of diffraction patterns on the encapsulation layer, and, wherein:
a first duplicate emission pattern is generated from a reference emission pattern by the plurality of diffraction patterns, and
the first duplicate emission pattern is separated from the reference emission pattern by a diffraction distance,
wherein:
the air has a second refractive index,
the encapsulation layer has a third refractive index, and
the diffraction distance satisfies an equation (6):
β
=
z
1
·
tan
[
sin
-
1
(
λ
DP
1
·
1
n
151
)
]
+
z
2
·
tan
[
sin
-
1
(
λ
DP
1
·
1
nEN
)
]
(
6
)
where β is the diffraction distance, z 1 is a shortest distance between the common electrode and the encapsulation layer, z 2 is a thickness of the encapsulation layer, DP 1 is the first period, n 151 is the second refractive index, nEN is the third refractive index, and λ is a wavelength of the light emitted from the display element.
15. A display device comprising:
a substrate;
a pixel electrode on the substrate;
a display element emitting a light and disposed on the pixel electrode;
a common electrode on the display element;
an encapsulation layer on the common electrode;
an air between the display element and the encapsulation layer; and
a plurality of diffraction patterns on the encapsulation layer,
wherein:
the plurality of diffraction patterns include a first diffraction pattern, a second diffraction pattern, and a third diffraction pattern,
the first diffraction pattern neighbors the third diffraction pattern along a first direction in a plan view, and
the first diffraction pattern neighbors the second diffraction pattern along a diagonal direction between the first direction and a second direction crossing the first direction and spaced apart from the second diffraction pattern with a predetermined distance in the plan view,
wherein:
a period between the first diffraction pattern and the second diffraction pattern is a 1a th period,
a period between the first diffraction pattern and the third diffraction pattern is a 1b th period,
a first duplicate emission pattern and a second duplicate emission pattern are generated from a reference emission pattern by the first diffraction pattern, the second diffraction pattern, and the third diffraction pattern,
the first duplicate emission pattern is separated from a reference emission pattern by a first diffraction distance,
the second duplicate emission pattern is separated from the reference emission pattern by a second diffraction distance,
the air has a second refractive index,
the encapsulation layer has a third refractive index,
the diffraction patterns have a tenth thickness, and
the first diffraction distance or the second diffraction distance is given by Equation (18):
β4
a
=
z
1
·
tan
[
sin
-
1
(
2
λ
3
·
DP
12
a
·
1
n
151
)
]
+
z
2
·
tan
[
sin
-
1
(
2
λ
3
·
DP
12
a
·
1
nEN
)
]
(
18
)
where β 4 a is the first diffraction distance or the second diffraction distance, z 1 is a shortest distance between the common electrode and the encapsulation layer, z 2 is a thickness of the encapsulation layer, DP 12 a is the lath period, DP 12 b is the 1b th period, n 151 is the second refractive index, nEN is the third refractive index, and λ is a wavelength of the light emitted from the display element.
16. The display device of claim 15 , wherein the second diffraction pattern and the third diffraction pattern are arranged to have an angle of Φ 1 with respect to the first diffraction pattern.
17. The display device of claim 16 , wherein the angle of Φ 1 is 60 degrees.
18. A display device comprising:
a substrate;
a pixel electrode on the substrate;
a display element emitting a light and disposed on the pixel electrode;
a common electrode on the display element;
an encapsulation layer on the common electrode; and
a plurality of diffraction patterns on the encapsulation layer, wherein: the plurality of diffraction patterns include a first diffraction pattern, a second diffraction pattern, and a third diffraction pattern,
a first duplicate emission pattern and a second duplicate emission pattern are generated from a reference emission pattern by the first diffraction pattern, the second diffraction pattern, and the third diffraction pattern,
the first duplicate emission pattern is separated from a reference emission pattern by a first diffraction distance, and
the second duplicate emission pattern is separated from the reference emission pattern by a second diffraction distance,
wherein:
the first diffraction pattern neighbors the third diffraction pattern along the first direction in a plan view,
the first diffraction pattern neighbors the second diffraction pattern along a diagonal direction between the first direction and the second direction and spaced apart from the second diffraction pattern with a predetermined distance in the plan view,
the second diffraction pattern and the third diffraction pattern are arranged to have an angle of ϕ 1 with respect to the first diffraction pattern,
a period between the first diffraction pattern and the second diffraction pattern is a 1a th period,
a period between the first diffraction pattern and the third diffraction pattern is a 1b th period,
the air has a second refractive index,
the encapsulation layer has a third refractive index,
the diffraction patterns have a tenth thickness, and
the first diffraction distance or the second diffraction distance is given by Equation (18):
β4
a
(
β
4
b
)
=
z
1
·
tan
[
sin
-
1
(
2
λ
3
·
DP
12
a
·
1
n
151
)
]
+
z
2
·
tan
[
sin
-
1
(
2
λ
3
·
DP
12
a
·
1
nEN
)
]
(
18
)
where β 4 a is the first diffraction distance or the second diffraction distance, z 1 is a shortest distance between the common electrode and the encapsulation layer, z 2 is a thickness of the encapsulation layer, DP 12 a is the 1a th period, DP 12 b is the 1b thλ period, n 151 is the second refractive index, nEN is the third refractive index, and λ is a wavelength of the light emitted from the display element.
19. The display device of claim 18 , wherein the angle of Φ 1 is 60 degrees.
20. The display device of claim 18 further comprising an air between the display element and the encapsulation layer.