Flexible organic EL panel
With chemically-strengthened thin glass substrates provided with an alkali barrier film, if the light-absorbing or light-scattering nature of the alkali barrier film itself has lowered the light extraction efficiency, or if the surface of the alkali barrier film is insufficiently flat, there may consequently be an increase in leakage current of an organic EL element and a decrease in reliability, leaving room for improvement. Instead of such an alkali barrier film, by providing an organic EL panel with a barrier film of the present invention and also with an organic EL element on a chemically-strengthened thin glass substrate with a specific light extraction structure therebetween, the glass substrate having one principal surface that includes a smooth region of the present invention, a high-performance organic EL panel can be obtained without compromising the organic EL properties.
1. A flexible organic EL panel, comprising a chemically strengthened thin-plate glass base material having an average thickness of 2 mm or less and an organic EL element, and having a light-emitting region corresponding to the organic EL element on a light-emitting surface thereof,
wherein an element-forming substrate comprising an alkali barrier film comprising an amorphous silica-based film is formed on an entire surface of one main surface of the chemically strengthened thin-plate base material, and the organic EL element is formed in contact with an element-forming region of the alkali barrier film;
the alkali barrier film has a smooth surface region on a surface in the side in contact with the organic EL element; and further
the smooth surface region has a surface smoothness of Ra of 5 nm or less and includes the element-forming region in plan view.
2. The flexible organic EL panel according to claim 1 , wherein the alkali barrier film further comprises a photocurable resin-containing flattening layer between the amorphous silica-based film and the organic EL element in the smooth surface region, in plan view.
3. The flexible organic EL panel according to claim 2 , wherein the flattening layer is a light scattering flattening layer containing fine particles of a transparent metal oxide having a refractive index of 1.8 or more.
4. The flexible organic EL panel according to claim 2 , wherein the alkali barrier film further comprises an uneven layer in the element-forming region in plan view between the chemically strengthened thin-plate glass base material and the amorphous silica-based film, the uneven layer comprising at least one selected from the group consisting of a thermoplastic resin and glass frit, and the uneven layer having an uneven surface in the amorphous silica-based film side.
5. The flexible organic EL panel according to claim 4 , wherein the uneven layer is an acrylic resin-based uneven layer comprising an acrylic resin as a main component.