Light extraction transparent substrate for organic el element, and organic el element using the same

Abstract

A light extraction transparent substrate for an organic EL element includes a transparent supporting substrate; a diffraction grating having a first concavity and convexity layer having first concavities and convexities formed on a surface thereof, which is located on a surface of the transparent supporting substrate, and a microlens having a second concavity and convexity layer having second concavities and convexities formed on a surface thereof, which is located on a surface of the transparent supporting substrate. When a Fourier-transformed image is obtained by performing two-dimensional fast Fourier transform processing on a concavity and convexity analysis image obtained by analyzing the shape of each of the first and second concavities and convexities by use of an atomic force microscope, the Fourier-transformed image shows a circular or annular pattern substantially centered at an origin at which an absolute value of wavenumber is 0 μm.