| 摘要 |
PROBLEM TO BE SOLVED: To improve light extraction efficiency by effectively mitigating surface plasmon absorption in a cathode of organic EL lighting.SOLUTION: An organic EL element comprises: a translucent substrate including a first face and a second face; a transparent electrode and a cathode that are formed on the first face; a luminescent layer that is provided between the transparent electrode and the cathode; and a light extraction film that is disposed on the second face and has ruggedness. A plurality of recesses or projections are included on a surface of the cathode closer to the luminescent layer. In the organic EL element, a Fourier transformation image on the surface of the cathode closer to the luminescent layer includes: one or more surface plasmon absorption suppression regions including a spatial frequency ν that is calculated by a formula (I) (in the formula, εis a dielectric constant of the luminescent layer, εis a dielectric constant of the cathode, Re() is a function that extracts a real part of a complex and λ is a central wavelength of an emission spectrum of the luminescent layer), and one or more light scattering regions not including a spatial frequency equal to or higher than the spatial frequency ν.SELECTED DRAWING: None |
