Organic light-emitting diode (OLED) display capable of controlling light transmittance

1. An organic light-emitting diode (OLED) display, comprising:

at least one pixel including a first region that emits light and a second region configured to selectively transmit external light received from one side of the OLED display so as to be emitted from an opposing side of the OLED display;

at least one thin film transistor (TFT) formed in the first region of the pixel;

an insulating layer formed over the TFT;

at least one first electrode formed in the first region of the pixel over the insulating layer;

at least one organic layer formed over the first electrode;

a second electrode formed over the organic layer;

at least one third electrode corresponding to the pixel, wherein the third electrode is formed in the second region of the pixel;

at least one solvent placed over the third electrode, wherein the solvent selectively blocks the external light from being transmitted through the OLED display based at least in part on an electric field; and

a fourth electrode formed over the solvent,

wherein a transmission opening is formed in the insulating layer in the second region of the pixel,

wherein the solvent is placed in the transmission opening,

wherein the at least one TFT comprises i) an active layer and ii) a gate electrode insulated from the active layer, and

wherein the at least one third electrode is disposed on a same layer as the active layer.

2. The OLED display of claim 1 , wherein the first electrode is a light reflecting electrode and the third electrode is a light transmitting electrode.

3. The OLED display of claim 1 , wherein the first region of the pixel comprises i) a circuit including the TFT and ii) an emission area including the first electrode and wherein the circuit region and the emission area substantially overlap each other.

4. The OLED display of claim 2 , wherein the fourth and second electrodes are integrally formed.

5. The OLED display of claim 1 , wherein the first and third electrodes are light transmitting electrodes.

6. The OLED display of claim 1 , wherein the first region of the pixel comprises i) a circuit including the TFT and ii) an emission area including the first electrode and wherein the circuit region and the emission area are adjacent to each other.

7. The OLED display of claim 5 , wherein the fourth and second electrodes are separately formed.

8. The OLED display of claim 1 , wherein the OLED display is further configured to respectively generate electric fields i) between the first and second electrodes and ii) between the third and fourth electrodes, wherein when the OLED display generates the electric field between the first and second electrodes, the OLED display does not generate the electric field between the third and fourth electrodes and wherein when the OLED display does not generate the electric field between the first and second electrodes, the OLED display generates the electric field between the third and fourth electrodes.

9. The OLED display of claim 8 , wherein when the electric field is not generated between the third and fourth electrodes, a light blocking area of the solvent is at a maximum and when the electric field is generated by the third and fourth electrodes, the light blocking area of the solvent is at a minimum.

10. The OLED display of claim 1 , wherein the solvent comprises black oil.

11. The OLED display of claim 10 , wherein a surface of the third electrode and a surface of the fourth electrode which contact the black oil are hydrophobic.

12. The OLED display of claim 1 , wherein the at least one pixel includes a plurality of pixels.

13. The OLED display of claim 12 , wherein the second electrode and the fourth electrode formed over the solvent for all of the pixels.

14. The OLED display of claim 12 , wherein each of the third electrodes corresponds to one of the pixels.

15. The OLED display of claim 12 , wherein each of the third electrodes corresponds to at least two adjacent pixels.

16. An organic light-emitting diode (OLED) display, comprising:

at least one pixel including a first region that emits light and a second region configured to selectively transmit external light received from one side of the OLED display so as to be emitted from an opposing side of the OLED display;

at least one first electrode formed in the first region of the pixel;

at least one organic layer formed over the first electrode;

a second electrode formed over the organic layer;

at least one third electrode corresponding to the pixel, wherein the third electrode is formed in the second region of the pixel;

at least one solvent placed over the third electrode in the second region, wherein the solvent selectively blocks the external light from being transmitted through the OLED display based at least in part on an electric field;

a fourth electrode formed over the at least one solvent;

a gate insulating layer;

an interlayer insulating layer formed over the gate insulating layer;

a passivation layer formed over the interlayer insulating layer; and

a pixel defining layer formed over the passivation layer,

wherein a transmission opening is formed in each of the gate insulating layer, the interlayer insulating layer, the passivation layer, and the pixel defining layer in the second region of the pixel, and

wherein the at least one solvent is placed in the transmission opening.