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 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,
wherein 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, and
wherein each of the plurality of diffraction patterns has a first refractive index and further comprising an intermediate layer which is disposed on the plurality of diffraction patterns and has a second refractive index, wherein the first refractive index, the second refractive index, and a thickness of one of the plurality of diffraction patterns satisfy Inequality (4):
( m *λ)−60 (nm)≤ A (nm)≤( m *λ)+60 (nm)
A≠Δn·t 1 (nm), (4)
where 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 one of the plurality of diffraction patterns, λ is a wavelength of the light emitted from the first display element, and m is an integer of 0 or more.
2. The display device of claim 1 , further comprising an encapsulation layer which is disposed between the first display element and the plurality of diffraction patterns.
3. The display device of claim 2 , wherein the encapsulation layer is a glass substrate.
4. The display device of claim 3 , wherein the plurality of diffraction patterns comprise the same material as that of the encapsulation layer.
5. The display device of claim 2 , wherein the encapsulation layer comprises at least one of an organic layer and an inorganic layer.
6. The display device of claim 2 , wherein the plurality of diffraction patterns generate a reference emission pattern and a first duplicate emission pattern by diffracting the light emitted from the first display element.
7. The display device of claim 6 , wherein luminance of the first duplicate emission pattern is 3% or more of luminance of the reference emission pattern.
8. The display device of claim 6 , wherein when a distance between the reference emission pattern and the first duplicate emission pattern is defined as a diffraction distance and a distance between the first display element and the plurality of diffraction patterns is defined as a separation distance, the diffraction distance satisfies Equation (2):
β
=
z
·
tan
[
sin
-
1
(
λ
DP
1
·
1
nEN
)
]
,
(
2
)
where β is the diffraction distance, z is the separation distance, DP 1 is the first period, λ is a wavelength of the light emitted from the first display element, and nEN is a refractive index of the encapsulation layer.
9. The display device of claim 6 , further comprising a second display element which is disposed on the substrate, wherein the second display element displays the same color as that of the first display element, and when a distance between the first display element and the second display element is defined as an inter-display element distance and a distance between the reference emission pattern and the first duplicate emission pattern is defined as a diffraction distance, the inter-display element distance and the diffraction distance satisfy Inequality (3):
0.1≤β/ PP 1≤1.9, (3)
where PPI is the inter-display element distance, and β is the diffraction distance.
10. The display device of claim 1 , wherein a cross-sectional shape of each of the plurality of diffraction patterns comprises at least one of a circular shape and a quadrilateral shape.
11. An organic light emitting display device comprising:
a substrate;
a first organic light emitting element which is disposed on the substrate;
an encapsulation layer which is disposed on the first organic light emitting element; and
a plurality of diffraction patterns which are disposed on the encapsulation layer and generate a reference emission pattern and a first duplicate emission pattern by diffracting light emitted from the first organic light emitting element,
wherein the plurality of diffraction patterns are arranged along a direction with a first period, and when a distance between the reference emission pattern and the first duplicate emission pattern is defined as a diffraction distance and a distance between the first organic light emitting element and the plurality of diffraction patterns is defined as a separation distance, the diffraction distance satisfies Equation (1):
β
=
z
·
tan
[
sin
-
1
(
λ
DP
1
·
1
nEN
)
]
,
(
1
)
where β is the diffraction distance, z is the separation distance, DP 1 is the first period, λ is a wavelength of the light emitted from the first organic light emitting element, and nEN is a refractive index of the encapsulation layer.
12. The organic light emitting display device of claim 11 , wherein 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 (2):
0.4≤ d 1/ DP 1≤1, (2)
where DP 1 is the first period, and d 1 is the first length.
13. The organic light emitting display device of claim 12 , further comprising an intermediate layer which is disposed on the plurality of diffraction patterns and has a first refractive index and wherein each of the plurality of diffraction patterns has a second refractive index, wherein the first refractive index, the second refractive index, and a thickness of one of the plurality of diffraction patterns satisfy Inequality (3):
( m *λ)−60 (nm)≤ A (nm)≤( m *λ)+60 (nm)
A≠Δn·t 1 (nm), (3)
where 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 one of the plurality of diffraction patterns, λ is the wavelength of the light emitted from the first organic light emitting element, and m is an integer of 0 or more.
14. The organic light emitting display device of claim 13 , wherein luminance of the first duplicate emission pattern is 3% or more of luminance of the reference emission pattern.
15. The organic light emitting display device of claim 11 , further comprising a second organic light emitting element which is disposed on the substrate, wherein the second organic light emitting element emits light of the same color as that of light emitted from the first organic light emitting element, and when a distance between the first organic light emitting element and the second organic light emitting element is defined as an inter-organic light emitting element distance, the inter-organic light emitting element distance and the diffraction distance satisfy Inequality (4):
0.1≤β/ PP 1≤1.9, (4)
where PPI is the inter-organic light emitting element distance, and β is the diffraction distance.
16. The organic light emitting display device of claim 11 , wherein the encapsulation layer is a glass substrate.
17. The organic light emitting display device of claim 11 , wherein the encapsulation layer comprises at least one of an organic layer and an inorganic layer.
18. A head-mounted display device comprising:
a display unit which comprises a first display element and a plurality of diffraction patterns disposed on a path of light emitted from the first display element; and
a lens unit which is disposed on the path of the light emitted from the display unit,
wherein the plurality of diffraction patterns are arranged along a direction with a first period, and 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,
wherein the plurality of diffraction patterns generate a reference emission pattern and a first duplicate emission pattern by diffracting the light emitted from the first display element,
wherein an effective emission area ratio is defined as a ratio of the area of emission patterns existing in a region to the area of the region,
wherein the emission patterns used to calculate the effective emission area ratio include both the reference emission pattern and the first duplicate emission pattern.
19. The head-mounted display device of claim 18 , further comprising an encapsulation layer which is disposed between the first display element and the plurality of diffraction patterns.
20. The head-mounted display device of claim 19 , wherein the encapsulation layer is a glass substrate.
21. The head-mounted display device of claim 19 , wherein the encapsulation layer comprises at least one of an organic layer and an inorganic layer.
22. The head-mounted display device of claim 21 , wherein the display unit further comprises a protective layer which is disposed on the plurality of diffraction patterns to cover the plurality of diffraction patterns.
23. The head-mounted display device of claim 19 , wherein the plurality of diffraction patterns generate a reference emission pattern and a first duplicate emission pattern by diffracting the light emitted from the first display element.
24. The head-mounted display device of claim 23 , wherein when a distance between the reference emission pattern and the first duplicate emission pattern is defined as a diffraction distance and a distance between the first display element and the plurality of diffraction patterns is defined as a separation distance, the diffraction distance satisfies Equation (2):
β
=
z
·
tan
[
sin
-
1
(
λ
DP
1
·
1
nEN
)
]
,
(
2
)
where β is the diffraction distance, z is the separation distance, DP 1 is the first period, λ is a wavelength of the light emitted from the first display element, and nEN is a refractive index of the encapsulation layer.
25. The head-mounted display device of claim 23 , wherein the display unit further comprises a second display element which displays the same color as that of the first display element, and when a distance between the first display element and the second display element is defined as an inter-display element distance and a distance between the reference emission pattern and the first duplicate emission pattern is defined as a diffraction distance, the inter-display element distance and the diffraction distance satisfy Inequality (3):
0.1≤β/ PP 1≤1.9, (3)
where PPI is the inter-display element distance, and β is the diffraction distance.
26. The head-mounted display device of claim 18 , further comprising an intermediate layer which is disposed between the plurality of diffraction patterns and the lens unit and has a first refractive index and wherein each of the plurality of diffraction patterns has a second refractive index, wherein the first refractive index, the second refractive index, and a thickness of one of the plurality of diffraction patterns satisfy Inequality (4):
( m *λ)−60 (nm)≤ A (nm)≤( m *λ)+60 (nm)
A≠Δn·t 1 (nm), (4)
where 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 one of the plurality of diffraction patterns, λ is the wavelength of the light emitted from the first display element, and m is an integer of 0 or more.
27. The head-mounted display device of claim 18 , wherein a cross-sectional shape of each of the plurality of diffraction patterns comprises at least one of a circular shape and a quadrilateral shape.
28. A head-mounted display device comprising:
a first display element;
a second display element which displays the same color as that of the first display element;
a plurality of diffraction patterns which are disposed on a path of light emitted from the first and second display elements and generate a reference emission pattern and a first duplicate emission pattern by diffracting light emitted from the first display element; and
an intermediate layer which is disposed on the plurality of diffraction patterns and has a first refractive index,
wherein the plurality of diffraction patterns are arranged along a direction with a first period and each have a second refractive index, wherein 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) below, when a distance between the reference emission pattern and the first duplicate emission pattern is defined as a diffraction distance and a distance between the first display element and the plurality of diffraction patterns is defined as a separation distance, the diffraction distance satisfies Equation (2) below, when a distance between the first display element and the second display element is defined as an inter-display element distance, the inter-display element distance and the diffraction distance satisfy Inequality (3) below, and the first refractive index, the second refractive index, and a thickness of one of the plurality of diffraction patterns satisfy Inequality (4) below:
0.4≤ d 1/ DP 1≤1, (1)
where DP 1 is the first period, and d 1 is the first length,
β
=
z
·
tan
[
sin
-
1
(
λ
DP
1
·
1
nEN
)
]
,
(
2
)
where β is the diffraction distance, z is the separation distance, DP 1 is the first period, λ is a wavelength of the light emitted from the first display element, and nEN is a refractive index of an encapsulation layer,
0.1≤β/ PP 1≤1.9, (3)
where PPI is the inter-display element distance, and β is the diffraction distance,
( m *λ)−60 (nm)≤ A (nm)≤( m *λ)+60 (nm)
A≠Δn·t 1 (nm), (4)
where 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 one of the plurality of diffraction patterns, λ is the wavelength of the light emitted from the first display element, and m is an integer of 0 or more.