Organic light emitting display device

1. An organic light emitting display device which displays an image in a first mode with a first driving frequency or an image in a second mode with a second driving frequency lower than the first driving frequency, the organic light emitting display device comprising:

a pixel unit including pixels to display the image in the first mode or the image in the second mode; and

a scan driver which supplies scan signals to the pixels through scan lines,

wherein a first image in the second mode is changed to a second image different from the first image in the second mode,

wherein the second image is displayed immediately after the first image with the first driving frequency during a predetermined period, and the second image is displayed with the second driving frequency after the predetermined period, and

wherein the second image to be displayed with the first driving frequency during the predetermined period and the second image to be displayed with the second driving frequency after the predetermined period are the same as each other.

2. The organic light emitting display device of claim 1 , wherein the predetermined period is an initial portion of an entire display period of the second image,

wherein the second image is displayed with the second driving frequency during a remaining portion of the entire display period of the second image, and

wherein the image in the second mode including the second image is a static image.

3. The organic light emitting display device of claim 2 , further comprising:

a first scan driver which supplies a first scan signal to first scan lines; and

a second scan driver which supplies a second scan signal to second scan lines,

wherein the pixels are coupled to the first scan lines and the second scan lines.

4. The organic light emitting display device of claim 3 , wherein

when the organic light emitting display device displays an image with the first driving frequency, the first scan driver repeatedly supplies the first scan signal to each of the first scan lines during every first unit frame period corresponding to the first driving frequency, and

when the organic light emitting display device displays the image with the first driving frequency, the second scan driver repeatedly supplies the second scan signal to each of the second scan lines during every first unit frame period.

5. The organic light emitting display device of claim 4 , wherein

when the organic light emitting display device displays an image with the second driving frequency, the first scan driver supplies k first scan signals to each of the first scan lines during a second unit frame period corresponding to the second driving frequency, wherein k is a natural number, and

when the organic light emitting display device displays the image with the second driving frequency, the second scan driver supplies j second scan signals to each of the second scan lines during the second unit frame period, wherein j is a natural number less than k.

6. The organic light emitting display device of claim 5 , wherein

the second unit frame period includes a first period and a second period,

when the organic light emitting display device displays the image with the second driving frequency, the second scan driver supplies the second scan signal to the second scan lines during the first period.

7. The organic light emitting display device of claim 6 , wherein the first period is equal to the first unit frame period.

8. The organic light emitting display device of claim 6 , wherein the second scan driver does not supply the second scan signal during the second period.

9. The organic light emitting display device of claim 6 , further comprising:

a data driver which supplies a data signal to data lines coupled to the pixels,

wherein the data driver supplies the data signal to be synchronized with the second scan signal.

10. The organic light emitting display device of claim 9 , wherein the data driver supplies a voltage of a reference power source to the data lines during a portion of the second unit frame period.

11. The organic light emitting display device of claim 6 , wherein the second period is longer than the first period.

12. The organic light emitting display device of claim 3 , wherein the first scan signal has a first voltage, and the second scan signal has a second voltage different from the first voltage.

13. The organic light emitting display device of claim 12 , wherein

each of pixels located on an i-th horizontal line comprises:

an organic light emitting diode; and

a pixel circuit coupled to an anode electrode of the organic light emitting diode, wherein

the pixel circuit controls an amount of current flowing through the organic light emitting diode, and

i is a natural number.

14. The organic light emitting display device of claim 13 , wherein the pixel circuit comprises:

a first transistor which controls an amount of current flowing from a first power source coupled to a first electrode thereof to a second power source via the organic light emitting diode, wherein the amount of the current is corresponding to a voltage of a node coupled to a gate electrode thereof;

a second transistor coupled between a data line and the first electrode of the first transistor, wherein the second transistor is turned on when an i-th first scan signal is supplied thereto;

a third transistor coupled between a second electrode of the first transistor and the node, wherein the third transistor is turned on when an i-th second scan signal is supplied thereto; and

a fourth transistor coupled between the node and an initialization power source, wherein the fourth transistor is turned on when an (i−1)-th second scan signal is supplied thereto.

15. The organic light emitting display device of claim 14 , wherein

the first transistor and the second transistor are P-type transistors, and

the third transistor and the fourth transistor are N-type oxide semiconductor transistors.

16. The organic light emitting display device of claim 15 , wherein the pixel circuit further includes:

a fifth transistor coupled between the first power source and the first transistor;

a sixth transistor coupled between the first transistor and the organic light emitting diode; and

a seventh transistor coupled between the initialization power source and the organic light emitting diode.

17. The organic light emitting display device of claim 16 , wherein the fifth transistor, the sixth transistor and the seventh transistor are P-type transistors.

18. The organic light emitting display device of claim 16 , wherein

the fifth transistor and the sixth transistor are P-type transistors, and

the seventh transistor is an N-type oxide semiconductor transistor.

19. A method of driving an organic light emitting display device which displays an image with a first driving frequency or with a second driving frequency lower than the first driving frequency, the method comprising:

displaying a first static image with the second driving frequency;

displaying a second static image immediately after the first static image with the first driving frequency during a predetermined period to change the first static image to the second static image; and

displaying the second static image with the second driving frequency immediately after the predetermined period,

wherein the second static image is displayed with the first driving frequency during the predetermined period, and the second static image is displayed with the second driving frequency after the predetermined period, and

wherein the second static image to be displayed with the first driving frequency during the predetermined period and the second static image to be displayed with the second driving frequency after the predetermined period are the same as each other.