Patent ID: 7537798

Claim:
A method of manufacturing an organic EL device, the method comprising: forming a first electrode layer in a predetermined pattern on an insulating substrate; forming an organic film comprising at least a patterned emission layer on the first electrode layer; and forming a second electrode layer in a predetermined pattern on the organic film; wherein the organic film and/or the second electrode layer are/is deposited using a deposition mask frame assembly, the deposition mask frame assembly comprising: a flat mask comprising a flat thin plate in which a predetermined pattern of apertures is formed, the flat mask having a first flat surface extending over an entire area of the flat mask, and a second flat surface extending over the entire area of the flat mask, the second flat surface being separated from the first flat surface by a thickness of the mask; a flat frame supporting the first flat surface of the flat mask so that the flat mask is tensed and the first flat surface remains flat; and a flat cover mask supporting the second flat surface of the flat mask so that the second flat surface remains flat; and wherein the flat mask, the flat frame, and the flat cover mask are held together by welds.