Pixel and organic light emitting display using the same
A pixel capable of displaying an image with uniform brightness. The pixel includes an organic light emitting diode (OLED), a first transistor controlling an amount of current that flows from a second node coupled to a first power supply to a second power supply via the OLED to correspond to a voltage applied to a first node, a second transistor coupled between the first node and an initializing power supply, and a third transistor turned on to supply a predetermined voltage to the second node at the moment when the second transistor is turned on.
1. A pixel, comprising:
an organic light emitting diode (OLED);
a first transistor controlling an amount of current that flows from a second node coupled to a first power supply to a second power supply via the OLED in response to a voltage applied to a first node;
a second transistor coupled between the first node and an initializing power supply; and
a third transistor turned on to supply a predetermined voltage to the second node at the moment when the second transistor is turned on, the third transistor coupled between the second node and one of an nth(where n is a natural number) emission control line, and an (n-1 )th emission control line, and a gate of the second transistor and a gate of the third transistor are connected to an (n-1)th scan line.
2. The pixel as claimed in claim 1 , wherein the predetermined voltage is set as a higher voltage than a voltage of the initializing power supply.
3. The pixel as claimed in claim 1 , wherein the second transistor and the third transistor are turned on when a scan signal is supplied to the(n-1)th scan line.
4. The pixel as claimed in claim 3 , further comprising:
a fourth transistor coupled between the second node and a data line and turned on when a scan signal is supplied to an nth scan line; and
a fifth transistor coupled between the first node and a second electrode of the first transistor and turned on when the scan signal is supplied to the nth scan line.
5. The pixel as claimed in claim 4 , wherein the predetermined voltage is higher than a voltage of the scan signal.
6. The pixel as claimed in claim 3 , further comprising:
a sixth transistor coupled between the second node and the first power supply and turned off when an emission control signal is supplied to the nth emission control line; and
a seventh transistor coupled between a second electrode of the first transistor and the OLED and turned off when an emission control signal is supplied to the nth emission control line.
7. The pixel as claimed in claim 6 , wherein the predetermined voltage is a voltage of the emission control signal.
8. The pixel as claimed in claim 4 , further comprising:
a storage capacitor coupled between the first node and the first power supply; and
a boosting capacitor coupled between the nth scan line and the first node.
9. An organic light emitting display device, comprising:
a scan driver sequentially supplying scan signals to scan lines and sequentially supplying emission control signals to emission control lines;
a data driver supplying data signals to data lines; and
pixels positioned at intersections of the scan lines and the data lines,
each of the pixels positioned on an nth (n is a natural number) horizontal line comprising:
an organic light emitting diode (OLED);
a first transistor controlling an amount of current that flows from a second node coupled to a first power supply to a second power supply via the OLED in response to a voltage applied to a first node;
a second transistor coupled between the first node and an initializing power supply and turned on when a scan signal is supplied to an (n-1)th (n is a natural number) scan line; and
a third transistor turned on to supply a predetermined voltage to the second node when the scan signal is supplied to the (n-1)th scan line, the third transistor coupled between the second node and one of an nth(where n is a natural number) emission control line, and an (n-1 )th emission control line, and a gate of the second transistor and a gate of the third transistor are connected to the (n-1 )th scan line.
10. The organic light emitting display device as claimed in claim 9 , wherein the predetermined voltage is set as a higher voltage than a voltage of the initializing power supply so that an on bias voltage is applied to the first transistor.
11. The organic light emitting display device as claimed in claim 9 , wherein each of the pixels comprises:
a fourth transistor coupled between the second node and a data line and turned on when a scan signal is supplied to an nth scan line; and
a fifth transistor coupled between the first node and a second electrode of the first transistor and turned on when the scan signal is supplied to the nth scan line.
12. The organic light emitting display device as claimed in claim 11 , wherein the predetermined voltage being higher than a voltage of the scan signal.
13. The organic light emitting display device as claimed in claim 9 , further comprising:
a sixth transistor coupled between the second node and the first power supply and turned off when an emission control signal is supplied to the nth emission control line; and
a seventh transistor coupled between a second electrode of the first transistor and the OLED and turned off when an emission control signal is supplied to the nth emission control line.
14. The organic light emitting display device as claimed in claim 13 , wherein the interval of time when the emission control signal is supplied to the nth emission control line overlaps the interval of time when scan signals are supplied to the (n-1)th scan line and the nth scan line.
15. The organic light emitting display device as claimed in claim 14 , wherein the predetermined voltage is a voltage of an emission control signal supplied to the (n-1)th emission control line.
16. The organic light emitting display device as claimed in claim 14 , wherein the predetermined voltage is a voltage of the emission control signal supplied to the nth emission control line.
17. The organic light emitting display device as claimed in claim 11 , further comprising:
a storage capacitor coupled between the first node and the first power supply; and
a boosting capacitor coupled between the nth scan line and the first node.