Color organic EL display and fabrication method thereof
View Patent ↗An organic EL display and a fabrication method high in light extraction efficiency are disclosed, wherein a plurality of organic layers interposed between an emissive layer and a reflective layer can be collectively formed for a plurality of subpixels, thereby reducing the number of mask processes for a lower fabrication cost and higher productivity. The organic EL display comprises a plurality of organic EL cells classified into at least three types of blue light emission, green light emission and red light emission, each including a plurality of organic layers having an emissive layer, a reflective electrode deposited on the first main surface of the organic layers and a transparent electrode deposited on the second main surface of the organic layer. The organic EL cells for green light emission and red light emission have an optical transparent conductive film interposed between the reflective electrode and the organic layer.
1. An organic EL display comprising a plurality of organic EL cells each including:
a plurality of organic layers including an emissive layer which have a first main surface and a second main surface;
a reflective electrode deposited on the first main surface of the organic layer; and
a transparent electrode deposited on the second main surface of the organic layer;
wherein the organic EL cells are classified into at least two types by the color emitted from the emissive layer of each organic EL cell; and
wherein at least one type of the organic EL cell has an optical transparent conductive film interposed between the reflective electrode and the organic layer.
2. An organic EL display comprising a plurality of organic EL cells each including:
a plurality of organic layers including an emissive layer which have a first main surface and a second main surface;
a reflective electrode deposited on the first main surface of the organic layer; and
a transparent electrode deposited on the second main surface of the organic layer;
wherein the organic EL cells are classified into at least three types of blue light emission, green light emission and red light emission by the color emitted from the emissive layer of each organic EL cell; and
wherein at least the organic EL cells for selected one of green light emission and red light emission have an optical transparent conductive film interposed between the reflective electrode and the organic layer.
3. The organic EL display according to claim 2 , wherein each of the three types of the organic EL cells include an optical transparent conductive film interposed between the reflective electrode and the organic layer, and wherein the optical transparent conductive film of the organic EL cell for green light emission and/or red light emission is thicker than the optical transparent conductive film of the organic EL cell for blue light emission.
4. The organic EL display according to claim 2 ,
wherein the organic EL cell for green light emission and/or red light emission has a longer distance between the emissive layer and the reflective electrode layer than the organic EL cell for blue light emission.
5. The organic EL display according to claim 2 ,
wherein all of the optical transparent conductive films of the organic EL cells for green light emission and/or red light emission have a substantially same thickness.
6. The organic EL display according to claim 2 ,
wherein the organic layers have at least selected one of a hole transporting layer and/or a hole injection layer or an electron transporting layer and/or an electron injection layer on the reflective electrode side of the emissive layer, and
wherein the thickness and the material of the hole transporting layer and/or the hole injection layer or the electron transporting layer and/or the electron injection layer are substantially same for all the organic EL cells for blue light emission, green light emission and red light emission.
7. The organic EL display according to claim 1 ,
wherein the distance from the first main surface of the organic layers to the emissive layer is substantially same for all of the organic EL cells.
8. The organic EL display according to claim 2 ,
wherein the distance from the first main surface of the organic layers to the emissive layer is substantially same for all of the organic EL cells.
9. A method of fabricating an organic EL display comprising a plurality of organic EL cells each including an emissive layer and at least one function layer, the organic EL cells being classified into at least three types of blue light emission, green light emission and red light emission by the color emitted from the emissive layer, the method comprising the steps of:
preparing a substrate;
forming a plurality of reflective electrodes on the substrate;
forming an optical transparent conductive film on each of the reflective electrodes corresponding to the organic EL cell for red light emission and/or green light emission;
forming at least one function layer over the whole surface of the substrate; and
forming the emissive layers for blue light emission, green light emission and red light emission on the one function layer corresponding to the organic EL cell for blue light emission, green light emission, and red light emission respectively.