Organic EL display and manufacturing method thereof
An organic EL display comprises an element substrate, an organic EL element formed on the element substrate, comprising an organic layer including a light emitting layer and a pair of electrode layers disposed on both sides of the organic layer. The organic layer comprises a first organic material. The organic EL display further comprises a capping layer comprising a second organic material having a glass transition point lower than one of the first organic material and a protective layer on the capping layer.
1. An organic EL display comprising:
an organic EL element comprising an organic layer including a light emitting layer, and a pair of electrode layers on both upper and lower sides of the organic layer, the organic layer comprising a first organic material;
a capping layer on the organic EL element, comprising a second organic material having a glass transition point lower than that of the first organic material;
a protective layer on the capping layer; and
a partition wall around the organic EL element, wherein
the capping layer covers at least a lower part of the partition wall while an upper part of the partition wall is exposed from the capping layer,
the capping layer has an optical thickness to resonate a traveling wave of light traveling from the capping layer toward the protective layer and a reflective wave of light traveling from an upper layer of the electrode layers toward the protective layer, and
the capping layer lies in a region enclosed in the partition wall and is interposed between the protective layer and the organic EL element.
2. An organic EL display according to claim 1 , wherein a difference in refractive indexes between the capping layer and the protective layer is within 0.7.
3. An organic EL display according to claim 1 , further comprising:
a circuit layer configured to control light emission of the organic EL element; and
a planarizing layer covering the circuit layer;
wherein the organic EL element is formed on the planarizing layer and a part of the protective layer is formed on the planarizing layer; and
wherein the capping layer has an extended portion on the planarizing layer, the extended portion covering at least a lower part of a second foreign matter between the protective layer and the planarizing layer while an upper part of the second foreign matter is exposed from the extended portion.
4. An organic EL display according to claim 3 , further comprising:
an element substrate comprising the circuit layer;
a cover substrate disposed on the element substrate to be opposite to the element substrate; and
a sealing material disposed between the element substrate and cover substrate, surrounding the organic EL element;
wherein the capping layer is formed inside a region surrounded by the sealing material.
5. An organic EL display according to claim 3 , further comprising:
an element substrate comprising the circuit layer;
a cover substrate disposed on the element substrate to be opposite to the element substrate; and
a sealing material disposed between the element substrate and cover substrate, contacting the protective layer on the organic EL element.
6. An organic EL display according to claim 1 , wherein the lower part of the partition wall is the lower side surface thereof.
7. An organic EL display according to claim 3 , wherein the lower part of the second foreign matter is the lower side surface thereof.
8. An organic EL display according to claim 1 , wherein the capping layer is in a thickness of 50 to 200 nm.