Flat panel display with high efficiency and method of fabricating the same
View Patent ↗An organic light emitting device is disclosed. In one embodiment, the organic light emitting device includes red (R), green (G) and blue (B) lower electrodes formed on a substrate. R, G, B organic thin film layers are formed on the R, G, B lower electrodes, respectively. Additionally, an upper single or multilayer electrode is formed over the substrate. Portions of the upper electrode that correspond to the R, G, B organic thin film layers, respectively, are formed to each have a different thickness. Various methods for forming the upper electrode using a fine metal mask, a halftone mask, and single and multiple photolithography processes are also disclosed.
1. A method of forming an organic light emitting device having R, G, B unit pixels, in which the R, G, B unit pixels comprise R, G, B lower electrodes formed on a substrate, R, G, B organic thin film layers each formed on the R, G, B lower electrodes, and an upper electrode formed over the substrate, the method comprising the steps of:
forming the upper electrode, the upper electrode being formed by:
forming a first upper electrode material on the substrate; and
forming a second upper electrode material on the first upper electrode material, the second upper electrode material having portions, each portion having a different thickness that corresponds to one of the R, G, B unit pixels,
wherein forming the second upper electrode material includes:
forming on portions of the first upper electrode material that corresponds to the R, G, B organic thin film layers, one or more first layers, each of the first layers having a different thickness that corresponds to one of the R, G, B unit pixels, respectively; and
forming a second layer in a uniform thickness on the first layer and the first upper is electrode material.
2. The method of claim 1 , wherein the first layers for the R, G, and B unit pixels of the second upper electrode material are deposited using a fine metal mask so that each of the R, G, and B unit pixels has the different thickness.
3. The method of claim 1 , wherein the first layers for the R, G, and B unit pixels of the second upper electrode material are patterned by three-time repetition of a photolithography so that each of the R, G, and B unit pixels has the different thickness.
4. The method of claim 1 , wherein the first layers for the R, G, and B unit pixels of the second upper electrode material are patterned by a single photolithography process using a halftone mask so that each of the R, G, and B unit pixels has the different thickness.
5. The method of claim 1 , wherein an emitting light is emitted in direction of the upper electrode.
6. A method of forming an organic light emitting device with R, G, B unit pixels, in which the R, G, B unit pixels comprise R, G, B lower electrodes formed on a substrate, R, G, B organic thin film layers each formed in the R, G, B lower electrodes, and an upper electrode formed over the substrate, the method comprising the steps of:
forming the upper electrode, the upper electrode being formed by:
forming a first upper electrode material on the substrate; and
forming a second upper electrode material on the first upper electrode material, the second upper electrode material having portions, each portion having a different thickness that corresponds to one of the R, G, B unit pixels,
wherein forming the second upper electrode material includes:
forming in a uniform thickness on the first upper electrode material a first layer; and
forming second layers for the R, G, B unit pixels on portions of the first layer that correspond to the R, G, B organic thin film layers, one or more second layers, so that each of the R, G, and B unit pixels has the different thickness.
7. The method of claim 6 , wherein the second layers for the R, G, and B unit pixels of the second upper electrode material are deposited using a fine metal mask so that each of the R, G, and B unit pixels has the same thickness.
8. The method of claim 6 , wherein the second layers for the R, G, and B unit pixels of the second upper electrode material are patterned by three-time repetition of a photolithography process so that each of the R, G, and B unit pixels has the different thickness.
9. The method of claim 6 , wherein the second layers for the R, G, and B unit pixels of the second upper electrode material are patterned by a single photolithography process using a halftone mask so that each of the R, G, and B unit pixels has the different thickness.
10. The method of claim 6 , wherein an emitting light is emitted in direction of the upper electrode.