Light Extraction Film for EL Elements, Surface Light Emitting Body, and Method for Producing Light Extraction Film for EL Elements

Abstract

A light extraction film for EL elements enables a surface light emitting body to have a good balance between suppression of emission angle dependence of the wavelength of emitted light and improvement of light extraction efficiency and luminance in the normal direction. A surface light emitting body has improved light extraction efficiency and luminance in the normal direction, while being suppressed in emission angle dependence of the wavelength of emitted light. A light extraction film for EL elements comprises a recessed and projected structure having a plurality of spherical projections, each containing a resin and fine particles added into the resin. The content of the fine particles in the spherical projections is 22-55% by mass, and the average maximum diameter (Aave) of the bottom portions of the spherical projections and the volume average particle diameter (P) of the fine particles satisfy the following mathematical formula (1). Aave/P≧5  (1)

Dependencies are inferred from the claim text.