Organic light emitting display device and method of driving the same

1. An organic light emitting display device comprising:

an anode and a cathode separated from each other;

a plurality of organic material layers formed between the anode and the cathode, one of the organic material layers comprising an organic light emitting layer;

a light source applying an excitation pulse to the organic material layers; and

a light receiving unit measuring changes in photoluminescence (PL) signals that are emitted from the organic material layers.

2. The organic light emitting display device of claim 1 , wherein the excitation pulse emitted from the light source is applied to the organic material layers after a voltage pulse is applied between the anode and the cathode and before an electroluminescence (EL) operation starts.

3. The organic light emitting display device of claim 2 , wherein the voltage pulse, the excitation pulse, and the changes of the PL signals respectively correspond to a gate pulse applied to a gate, a source pulse applied a source, and a signal output from a drain of a photoelectric transistor.

4. The organic light emitting display device of claim 1 , wherein the organic light emitting layer is disposed between a first one of the organic material layers and a second one of the organic material layers.

5. The organic light emitting display device of claim 4 , wherein the first one of the organic material layers comprises a hole injection layer and a hole transport layer that are sequentially stacked between the anode and the organic light emitting layer.

6. The organic light emitting display device of claim 4 , wherein the second one of the organic material layers comprises an electron injection layer and an electron transport layer that are sequentially stacked between the cathode and the organic light emitting layer.

7. The organic light emitting display device of claim 4 , wherein the organic light emitting layer comprises at least one of a red light emitting layer, a green light emitting layer, and a blue light emitting layer.

8. The organic light emitting display device of claim 1 , wherein the excitation pulse has a band gap energy that is greater than that of the organic light emitting layer.

9. The organic light emitting display device of claim 1 , wherein the light receiving unit measures a change in intensity or a decay time of the PL signal emitted from each of the organic material layers.

10. The organic light emitting display device of claim 1 , further comprising a first waveguide disposed between the light source and the organic material layers for guiding the excitation pulse emitted from the light source toward the organic material layers.

11. The organic light emitting display device of claim 10 , further comprising a second waveguide disposed between the organic material layers and the light receiving unit for guiding the PL signals emitted from the organic material layers toward the light receiving unit.

12. The organic light emitting display device of claim 1 , further comprising a PL blocking layer formed on the cathode for preventing the PL signals emitted from the organic material layers from leaking.

13. The organic light emitting display device of claim 1 , wherein the excitation pulse emitted from the light source is incident to an end portion of a lower surface of the organic material layers that is closest to the light source, and the PL signals are emitted from the other end portion on the lower surface.

14. A method of driving an organic light emitting display device, which comprises an anode and a cathode separated from each other, and a plurality of organic material layers formed between the anode and the cathode, the method comprising:

applying a voltage pulse between the anode and the cathode;

applying a predetermined excitation pulse to the organic material layers from a light source after the application the voltage pulse and before an electroluminescence (EL) operation starts; and

measuring changes in photoluminescence (PL) signals emitted from the organic material layers.

15. The method of claim 14 , wherein the voltage pulse, the excitation pulse, and the changes of the PL signals respectively correspond to a gate pulse applied to a gate, a source pulse applied to a source, and a signal output from a drain in a photoelectric transistor.

16. The method of claim 14 , wherein the excitation pulse emitted from the light source has a band gap energy that is greater than that of the organic light emitting layer.

17. The method of claim 14 , wherein the step of measuring changes in the PL signals comprising measuring a change in intensity or a decay time of the PL signals.

18. The method of claim 14 , wherein each of a width of the excitation pulse and a width of the PL signal is less than a width of the voltage pulse.

19. A method of driving an organic light emitting display device, which comprises an anode and a cathode separated from each other, a plurality of organic material layers formed between the anode and the cathode, a light source applying a predetermined excitation pulse to the organic material layers, and a light receiving unit measuring changes in photoluminescence (PL) signals that are emitted from the organic material layers, the method comprising:

applying a predetermined voltage pulse between the anode and the cathode;

applying the predetermined excitation pulse to the organic material layers from the light source;

measuring changes in PL signals that are emitted from the organic material layers using the light receiving unit; and

starting an electroluminescence (EL) operation in the organic light emitting layer.