Organic electroluminescent display panel with auxiliary electrodes, method for manufacturing the same, and display device using the same

1. An organic electroluminescent display panel, comprising:

a plurality of sub-pixels, wherein each of the plurality of sub-pixels comprises:

a planarization layer;

a pixel electrode formed on the planarization layer;

an auxiliary electrode coated by the planarization layer, wherein the auxiliary electrode is continuous and the pixel electrode overlaps the auxiliary electrode;

a pixel defining layer covering at least a part of a marginal region of the pixel electrode to define a pixel defining opening exposing at least a part of the pixel electrode,

wherein the planarization layer defines a plurality of contact holes extending to a top surface of the planarization layer to have the auxiliary electrode in direct contact with the pixel electrode through each of the plurality of contact holes,

wherein the plurality of contact holes surround the pixel defining opening, and

an array substrate,

wherein the planarization layer is formed on the array substrate, and orthographic projections of the plurality of contact holes on the array substrate are all located within an orthographic projection of the auxiliary electrode on the array substrate.

2. The organic electroluminescent display panel of claim 1 , wherein the orthographic projections of the plurality of contact holes on the array substrate are all located within an orthographic projection of the pixel defining layer.

3. The organic electroluminescent display panel of claim 1 , wherein the planarization layer is patterned by a patterning process to form the plurality of contact holes surrounding the pixel defining opening.

4. The organic electroluminescent display panel of claim 1 , wherein a distance from the planarization layer to a top surface of the pixel defining layer is greater than a distance from the planarization layer to a top surface of the pixel electrode.

5. The organic electroluminescent display panel of claim 1 , wherein a distribution density of the plurality of contact holes in a central region of the display panel is greater than that in a frame-adjacent region of the display panel.

6. The organic electroluminescent display panel of claim 1 , wherein the each of the plurality of contact holes has a first end away from the auxiliary electrode and a second end adjacent to the auxiliary electrode, and a radial size of the each of the plurality of contact holes is gradually reduced from the first end to the second end.

7. The organic electroluminescent display panel of claim 1 , wherein the each of the plurality of contact holes is filled with a pixel electrode material to contact the pixel electrode with the auxiliary electrode.

8. The organic electroluminescent display panel of claim 1 , wherein the planarization layer comprises a first planarization layer and a second planarization layer stacked one by one, the auxiliary electrode is disposed on the first planarization layer and covered by the second planarization layer, and the second planarization layer defines the plurality of contact holes to expose a part of the auxiliary electrode.

9. The organic electroluminescent display panel of claim 1 , wherein the auxiliary electrode includes a first auxiliary electrode and a second auxiliary electrode spaced from each other along an up-to-down direction and disposed in the planarization layer, the second auxiliary electrode contacts the pixel electrode via the plurality of contact holes, and the planarization layer further defines a joint hole to have the first auxiliary electrode and the second auxiliary electrode joined to each other.

10. The organic electroluminescent display panel of claim 9 , wherein the plurality of contact holes and the joint hole are staggered with each other in a direction parallel to an array substrate of the display panel.

11. The organic electroluminescent display panel of claim 9 , wherein the pixel electrode and the auxiliary electrode are joined to each other via the plurality of contact holes to form a three-dimensional network structure to support the pixel electrode.

12. A display device, comprising:

an organic electroluminescent display panel, comprising:

a sub-pixel, wherein the sub-pixel comprises:

a planarization layer;

a pixel electrode formed on the planarization layer;

an auxiliary electrode coated by the planarization layer, wherein the auxiliary electrode is continuous and the pixel electrode overlaps the auxiliary electrode;

a pixel defining layer covering at least a part of a marginal region of the pixel electrode to define a pixel defining opening exposing at least a part of the pixel electrode,

wherein the planarization layer defines a plurality of contact holes extending to a top surface of the planarization layer to have the auxiliary electrode directly contacted with the pixel electrode through each of the plurality of contact holes, wherein the plurality of contact holes surround the pixel defining opening; and

an array substrate,

wherein the planarization layer is formed on the array substrate, and orthographic projections of the plurality of contact holes on the array substrate are all located within an orthographic projection of the auxiliary electrode on the array substrate; and a control unit configured to transmit a display signal to the organic electroluminescent display panel.

13. The display device of claim 12 , wherein the orthographic projections of the plurality of contact holes on the array substrate are all located within an orthographic projection of the pixel defining layer.

14. The display device of claim 12 , wherein the planarization layer is patterned by a patterning process to form the plurality of contact holes surrounding the pixel defining opening.

15. The display device of claim 12 , wherein a distance from the planarization layer to a top surface of the pixel defining layer is greater than a distance from the planarization layer to a top surface of the pixel electrode.

16. A method for manufacturing a sub-pixel of an organic electroluminescent display panel, comprising:

providing an array substrate;

forming an auxiliary electrode and a planarization layer, wherein the planarization layer is configured to coat the auxiliary electrode and define a plurality of contact holes extending to a top surface of the planarization layer, wherein the auxiliary electrode is continuous; and

forming a pixel electrode on the planarization layer, wherein the pixel electrode overlaps the auxiliary electrode, and

directly contacting the auxiliary electrode with the pixel electrode via each of the plurality of contact holes,

forming a pixel defining layer on the planarization layer to cover at least a part of a marginal region of the pixel electrode to define a pixel defining opening exposing at least a part of the pixel electrode, wherein the plurality of contact holes surround the pixel defining opening, and wherein the planarization layer is formed on the array substrate, and orthographic projections of the plurality of contact holes on the array substrate are all located within an orthographic projection of the auxiliary electrode on the array substrate.

17. The method of claim 16 , wherein the forming the auxiliary electrode and the planarization layer comprises: forming a first planarization layer; forming the auxiliary electrode on the first planarization layer; and forming a second planarization layer on the first planarization layer to coat the auxiliary electrode.

18. The method of claim 16 , after the forming the pixel electrode on the planarization layer, further comprising: filling the each of the plurality of contact holes with a pixel electrode material.