Electroluminescent display device and method of manufacturing the same

1. An electroluminescent display device comprising:

a plurality of sub-pixels arranged on a substrate, the plurality of sub-pixels including sub-pixels with different colors arranged along a first direction and sub-pixels with the same color arranged along a second direction;

a light-emitting diode disposed at each sub-pixel and including a first electrode, a light-emitting layer and a second electrode;

a first bank disposed between adjacent sub-pixels along the second direction and overlapping edges of the first electrode;

a second bank having an opening corresponding to the sub-pixels arranged along the second direction and disposed between adjacent sub-pixels along the first direction; and

a third bank on side surfaces of the second bank facing each other along the second direction corresponding to the opening.

2. The electroluminescent display device of claim 1 , wherein the first and third banks have a hydrophilic property and the second bank has a hydrophobic property.

3. The electroluminescent display device of claim 2 , wherein the third bank has a higher surface energy than the first bank.

4. The electroluminescent display device of claim 1 , wherein the third bank is further formed partially on a top surface of the second bank.

5. The electroluminescent display device of claim 1 , wherein the first bank further includes a portion formed between adjacent sub-pixels along the first direction.

6. The electroluminescent display device of claim 5 , wherein the portion of the first bank formed between the adjacent sub-pixels along the first direction is formed under the second bank.

7. The electroluminescent display device of claim 1 , wherein light-emitting layers on first electrodes of the sub-pixels arranged along the second direction are connected to a light-emitting layer on the first bank between adjacent sub-pixels along the second direction to form one body.

8. The electroluminescent display device of claim 1 , wherein the emitting layer has a higher height in an edge portion of the opening of the second bank than in a center portion of the opening.

9. The electroluminescent display device of claim 1 , wherein the first bank and the second bank are formed through a half-tone mask process.

10. The electroluminescent display device of claim 1 , wherein the light-emitting layer is formed through a solution process.

11. A method of manufacturing an electroluminescent display device, the method comprising:

forming a first electrode in each sub-pixel on a substrate on which a plurality of sub-pixels including sub-pixels with different colors arranged along a first direction and sub-pixels with the same color arranged along a second direction are defined;

forming a first bank disposed between adjacent sub-pixels along the second direction, the first bank overlapping edges of the first electrode;

forming a second bank on the first bank, the second bank having an opening corresponding to the sub-pixels arranged along the second direction and disposed between adjacent sub-pixels along the first direction;

forming a photoresist pattern corresponding to the opening, the photoresist pattern covering the first electrode and the first bank and exposing the second bank;

forming a first insulating pattern and a second insulating pattern, the first insulating pattern disposed on a top surface and side surfaces of the second bank, and the second insulating pattern disposed on the photoresist pattern;

forming a third bank on the side surfaces of the second bank by removing the photoresist pattern and the second insulating pattern;

forming a solution layer in the opening and contacting the third bank;

forming a light-emitting layer by drying the solution layer; and

forming a second electrode on the light-emitting layer.

12. The method of claim 11 , further comprising selectively removing the first insulating pattern on the top surface of the second bank before forming the third bank.

13. The method of claim 11 , wherein the first and third banks have a hydrophilic property and the second bank has a hydrophobic property.

14. The method of claim 13 , wherein the third bank has a higher surface energy than the first bank.