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US 10,651,415 B2Granted
Organic EL (electroluminescent) device
AssigneeToppan Printing Co., Ltd.
InventorsAkihito Kagotani, Toshiki Toda
Life of this patent
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Abstract
An organic EL (electroluminescent) device includes a translucent substrate, a transparent electrode, a luminescent layer, and a cathode placed over one surface of the translucent substrate, and a light extraction film having unevenness placed on the other surface. The surface of the cathode facing the luminescent layer has a plurality of recesses or protrusions. The Fourier transform image of the surface of the cathode facing the luminescent layer has a surface plasmon absorption suppression area including a spatial frequency v obtained from Eq. (I) and a light scattering area not including spatial frequencies equal to or greater than the spatial frequency v.
Claims20
An organic EL device, comprising:
- a translucent substrate having a first surface and a second surface opposite to the first surface;
- a transparent electrode formed on the first surface of the translucent substrate;
- a cathode having a surface on which a plurality of recesses or protrusions are formed;
- a luminescent layer formed between the transparent electrode and the cathode and facing the surface of the cathode having the recesses or protrusions;
- and
- a light extraction film positioned on the second surface of the translucent substrate and having unevenness,
- wherein the cathode has the recesses or protrusions formed such that the surface has a Fourier transform image which includes at least one surface plasmon absorption suppression area having a spatial frequency v and at least one light scattering area that does not include a spatial frequency equal to or greater than the spatial frequency v, and the spatial frequency v is obtained from Equation (I)
- ν
- =
- 1
- λ
- ⨯
- Re
-
- (
- ɛ
- 1
- ⨯
- ɛ
- 2
- ɛ
- 1
- +
- ɛ
- 2
- )
- (
- I
- )
- where ε1 is a relative permittivity of the luminescent layer, ε2 is a relative permittivity of the cathode, Re( ) is a function for extracting a real part of a complex number, and λ is a central wavelength of an emission spectrum of the luminescent layer, the at least one surface plasmon absorption suppression area includes the spatial frequency v in a range of from v2 to v1, and the at least one light scattering area does not include a spatial frequency in the range of from v2 to v1, where the spatial frequency v1 is a spatial frequency obtained by substituting λ of Equation (I) with λ1 obtained by Equation (II)
- λ1=k×λmin (II),
- the spatial frequency v2 is a spatial frequency obtained by substituting λ of Equation (I) with λ2 satisfying λ1<λ2 and obtained by Equation (III)
- λ2=(1/k)×λmax (III),
- λmin is a minimum wavelength satisfying S(λ)>S(λp)/100, λmax is a maximum wavelength satisfying S(λ)>S(λp)/100, k is a real number larger than 0.8, λp is a peak wavelength of the emission spectrum of the luminescent layer, and S(λ) is an intensity at the central wavelength λ.
31 more elements
An organic EL device, comprising:
- a translucent substrate having a first surface and a second surface opposite to the first surface;
- a transparent electrode formed on the first surface of the translucent substrate;
- a cathode having a surface on which a plurality of recesses or protrusions are formed;
- a luminescent layer formed between the transparent electrode and the cathode and facing the surface of the cathode having the recesses or protrusions;
- and
- a light extraction film positioned on the second surface of the translucent substrate and having unevenness,
- wherein the cathode has the recesses or protrusions formed such that the surface has a Fourier transform image which includes at least one surface plasmon absorption suppression area having a spatial frequency v and at least one light scattering area that does not include a spatial frequency equal to or greater than the spatial frequency v, and the spatial frequency v is obtained from Equation (I)
- ν
- =
- 1
- λ
- ⨯
- Re
-
- (
- ɛ
- 1
- ⨯
- ɛ
- 2
- ɛ
- 1
- +
- ɛ
- 2
- )
- (
- I
- )
- where ε1 is a relative permittivity of the luminescent layer, ε2 is a relative permittivity of the cathode, Re( ) is a function for extracting a real part of a complex number, and λ is a central wavelength of an emission spectrum of the luminescent layer, the luminescent layer has the emission spectrum having a plurality of emission peak wavelengths λp1 . . . λpn, and the surface plasmon absorption suppression area includes spatial frequencies vp1 . . . vpn obtained by substituting λ of Equation (I) with λp1 . . . λpn.
27 more elements
An organic EL device, comprising:
- a translucent substrate having a first surface and a second surface opposite to the first surface;
- a transparent electrode formed on the first surface of the translucent substrate;
- a cathode having a surface on which a plurality of recesses or protrusions are formed;
- a luminescent layer formed between the transparent electrode and the cathode and facing the surface of the cathode having the recesses or protrusions;
- a light extraction film positioned on the second surface of the translucent substrate and having unevenness;
- and
- an uneven structure layer having a plurality of protrusions or recesses and formed such that the uneven structure layer, the transparent electrode, the luminescent layer, and the cathode are positioned in an order thereof,
- wherein the cathode has the recesses or protrusions formed such that the surface has a Fourier transform image which includes at least one surface plasmon absorption suppression area having a spatial frequency v and at least one light scattering area that does not include a spatial frequency equal to or greater than the spatial frequency v, and the spatial frequency v is obtained from Equation (I)
- ν
- =
- 1
- λ
- ⨯
- Re
-
- (
- ɛ
- 1
- ⨯
- ɛ
- 2
- ɛ
- 1
- +
- ɛ
- 2
- )
- (
- I
- )
- where ε1 is a relative permittivity of the luminescent layer, ε2 is a relative permittivity of the cathode, Re( ) is a function for extracting a real part of a complex number, and λ is a central wavelength of an emission spectrum of the luminescent layer.
28 more elements
Dependencies are inferred from the claim text.