Organic electroluminescent display device with an upper electrode in contact with a lower electrode
In an organic EL display device, a resistance of a cathode electrode of OLEDs is substantially reduced while maintaining a higher opening ratio of pixels as an entire display area. A reference power supply line is formed on a glass substrate, and receives a reference potential for driving the OLED. The OLED is formed on the glass substrate where the reference power supply line is formed, and has a structure in which a lower electrode, an organic material layer, and an upper electrode that is a cathode electrode common to plural pixels are laminated on each other in the order from the bottom. In some of the plural pixels, a cathode contact that penetrates through the organic material layer, and electrically connects the upper electrode to the reference power supply line is formed within an opening area corresponding to a W sub-pixel.
1. An organic electroluminescent display device comprising:
a substrate;
a plurality of pixels formed on the substrate, each of the pixels including a lower electrode, a light emitting layer, and an upper electrode;
a bank partitioning the pixels and exposing the lower electrode;
a line formed on the substrate and under the lower electrode; and
an insulating film located between the line and the lower electrode,
wherein at least one of the pixels has a hole which penetrates through the light emitting layer and exposes the lower electrode, the hole being located where the lower electrode is exposed by the bank,
the insulating film has a contact hole which is different from the hole and overlaps the hole in plan view,
the lower electrode is on and in physical contact with the line at the contact hole,
the hole does not project into the insulating film,
the upper electrode is on and in physical contact with the lower electrode at the hole,
the upper electrode is electrically connected to the line via the lower electrode at the hole, and
the at least one of the pixels has a first sub pixel which includes a light emitting area and a second sub pixel which includes a non-emitting area corresponding to the hole and does not include a light emitting area.
2. The organic electroluminescent display device according to claim 1 , wherein the line supplies the upper electrode with a common voltage.
3. The organic electroluminescent display device according to claim 1 , wherein the upper electrode is common to the plurality of pixels.
4. The organic electroluminescent display device according to claim 1 , wherein the bank has a first opening which exposes the light emitting area and a second opening which exposes the non-emitting area in one of the pixels.
5. The organic electroluminescent display device according to claim 1 , wherein the plurality of pixels includes basic pixels and irregular pixels,
each of the irregular pixels has the first sub pixel and the second sub pixel,
the first sub pixel includes the hole,
and
each of the basic pixels does not include the hole.
6. The organic electroluminescent display device according to claim 1 , wherein
the lower electrode has an exposed region which is exposed by the hole,
the light emitting layer has an end region corresponding to an outer periphery of the hole,
the bank has a side surface surrounding the exposed region, and
the end region is located on the side surface.
7. An organic electroluminescent display device comprising:
a substrate;
a plurality of pixels formed on the substrate and arranged in a matrix, each of the pixels including a lower electrode, a light emitting layer, and an upper electrode which is common to the plurality of pixels;
a bank partitioning the pixels and exposing the lower electrode;
a line formed on the substrate and under the lower electrode, and supplying the upper electrode with a common voltage; and
an insulating film located between the line and the lower electrode,
wherein the pixels include first pixels and second pixels,
each of the first pixels emit light where the lower electrode is exposed by the bank,
each of the second pixels have a hole which penetrates through the light emitting layer and does not project into the insulating film, the hole being located where the lower electrode is exposed by the bank,
the upper electrode is on and in physical contact with the lower electrode at the hole in each of the second pixels,
the upper electrode is electrically connected to the line via the lower electrode at the hole in each of the second pixels,
the plurality of pixels includes basic pixels and irregular pixels,
each of the irregular pixels has a first sub pixel and at least one second sub pixel,
the first sub pixel includes the hole,
the second sub pixel does not include the hole, and
each of the basic pixels does not include the hole.
8. The organic electroluminescent display device according to claim 7 , wherein a plurality of lines including the line are formed on the substrate and under the lower electrode, and supply the upper electrode with a common voltage,
the plurality of lines extends in a first direction, and arranged in a second direction,
each of the lines overlaps some of the pixels arranged in the first direction, and
the overlapped pixels include at least one of the second pixels.
9. The organic electroluminescent display device according to claim 7 , wherein the insulating film has a contact hole which is different from the hole and overlaps the hole in plan view, and
the lower electrode is on and in physical contact with the line at the contact hole.
10. The organic electroluminescent display device according to claim 7 , wherein
the lower electrode has an exposed region which is exposed by the hole,
the light emitting layer has an end region corresponding to an outer periphery of the hole,
the bank has a side surface surrounding the exposed region, and
the end region is located on the side surface.