Organic light emitting device

1. An organic light emitting device, comprising:

an organic light emitting panel displaying an image;

a drive unit receiving image data corresponding to the image and providing a data voltage corresponding to the image data to the organic light emitting panel; and

a power supply unit providing a common voltage to the organic light emitting panel,

with the common voltage being varied to correspond to a maximum luminance of the image,

wherein when the maximum luminance of the image is changed from a first luminance to a second luminance that is higher than the first luminance, the common voltage is changed from a first voltage that corresponds to the first luminance to a second voltage that corresponds to the second luminance, and

wherein a time point where a shift from the first luminance to the second luminance completes is followed by a time point where a shift from the first voltage to the second voltage completes.

2. The organic light emitting device of claim 1 , wherein if the common voltage is varied to correspond to the maximum luminance of the image, the data voltage is varied to correspond to the maximum luminance of the image, and

if grayscales of the image are constant, a difference between the common voltage and the data voltage becomes constant.

3. The organic light emitting device of claim 1 , wherein a time in which the common voltage is changed from the first voltage to the second voltage is longer than a time in which the maximum luminance is changed from the first luminance to the second luminance.

4. The organic light emitting device of claim 1 , wherein if the maximum luminance of the image is changed from a third luminance to a fourth luminance, the common voltage is changed from a third voltage that corresponds to the third luminance to a fourth voltage that corresponds to the fourth luminance, and

a time period in which the common voltage is shifted from the third voltage to the fourth voltage includes a maintenance period in which the common voltage is maintained and a change period in which the common voltage is changed.

5. The organic light emitting device of claim 4 , wherein in the change period, the common voltage is a voltage between the third voltage and the fourth voltage.

6. The organic light emitting device of claim 4 , wherein the maintenance period includes first to n-th maintenance periods arranged in a time order,

the change period includes first to (n+1)-th change periods arrange in a time order, and

the first to n-th maintenance periods and the first to (n+1)-th change periods are arranged to cross each other.

7. The organic light emitting device of claim 6 , wherein each length of the first to n-th maintenance periods is the same as a length of a unit frame of the image that is displayed on the organic light emitting panel.

8. The organic light emitting device of claim 6 , wherein each length of the first to (n+1)-th change periods is the same as a length of a unit frame of the image that is displayed on the organic light emitting panel.

9. The organic light emitting device of claim 1 , wherein if the maximum luminance of the image is changed from a fifth luminance to a sixth luminance that is lower than the fifth luminance and a difference between the fifth luminance and the sixth luminance is smaller than a hysteresis luminance, the common voltage is not changed from a voltage that corresponds to the fifth luminance.

10. The organic light emitting device of claim 9 , wherein if the maximum luminance of the image is changed from the fifth luminance to the sixth luminance and then is changed from the sixth luminance to a seventh luminance between the fifth luminance and the sixth luminance, the common voltage is not changed from the voltage that corresponds to the fifth luminance.

11. The organic light emitting device of claim 9 , wherein if the maximum luminance of the image is changed from the fifth luminance to an eighth luminance that is lower than the fifth luminance and a difference between the fifth luminance and the eighth luminance is larger than the hysteresis luminance, the common voltage is shifted from a voltage that corresponds to the fifth luminance to a voltage that corresponds to the eighth luminance.

12. The organic light emitting device of claim 9 , wherein if the maximum luminance of the image is changed in a period between the fifth luminance and a luminance that is lower than the fifth luminance as much as the hysteresis luminance, from the fifth luminance, the common voltage is not changed from a fifth voltage that corresponds to the fifth luminance.

13. The organic light emitting device of claim 1 , wherein the drive unit comprises a luminance determination unit determining the maximum luminance of the image from the image data.

14. The organic light emitting device of claim 13 , wherein the drive unit further comprises:

an offset determination unit determining an offset voltage of the data voltage from the maximum luminance; and

a data voltage generation unit generating the data voltage of a level that corresponds to the offset voltage.

15. The organic light emitting device of claim 1 , wherein the power supply unit comprises:

a common voltage determination unit determining a level of the common voltage to correspond to the maximum luminance of the image; and

a common voltage generation unit generating the common voltage to correspond to the level of the common voltage.

16. The organic light emitting device of claim 15 , wherein the power supply unit comprises a data power generation unit supplying power to the drive unit to obtain synchronization between the data voltage and the common voltage.

17. An organic light emitting device, comprising:

an organic light emitting panel displaying an image;

a drive unit receiving image data corresponding to the image and image luminance discrimination signal that includes information on a maximum luminance of the image and providing a data voltage corresponding to the image luminance discrimination signal to the organic light emitting panel; and

a power supply unit providing a common voltage to the organic light emitting panel,

with the common voltage being varied to correspond to the image luminance discrimination signal,

wherein when the maximum luminance of the image is changed from a first luminance to a second luminance that is higher than the first luminance, the common voltage is changed from a first voltage that corresponds to the first luminance to a second voltage that corresponds to the second luminance, and

wherein a time point where a shift from the first luminance to the second luminance completes is followed by a time point where a shift from the first voltage to the second voltage completes.

18. The organic light emitting device of claim 17 , wherein if the common voltage is varied to correspond to the image luminance discrimination signal, the data voltage is also varied to correspond to the maximum luminance of the image, and

if grayscales of the image are constant, a difference between the common voltage and the data voltage becomes constant.