Organic light emitting diode display device and method of driving the same
Discussed is an OLED display device that can compensate for the deviation of a threshold voltage and also prevent deterioration of an OLED, and a method of driving the same, wherein the OLED display device includes first to fifth transistors, a driving transistor including gate, source and drain electrodes, a capacitor for sensing a threshold voltage of the driving transistor, and an OLED.
1. An organic light emitting diode (OLED) display device, comprising:
a first transistor configured to supply a data voltage to a first node according to a scan signal;
a second transistor connected to the first node and a second node supplied with a high-level source voltage, and configured to connect the first node and the second node to each other according to a first control signal;
a driving transistor having a gate electrode connected to a third node, a source electrode connected to the second node, and a drain electrode connected to a fourth node;
a capacitor connected between the first node and the third node, and configured to sense a threshold voltage of the driving transistor;
a third transistor configured to connect the third node and the fourth node to each other according to a second control signal;
a fourth transistor connected to the fourth node and a fifth node, and configured to connect the fourth node and the fifth node to each other according to the first control signal;
an OLED connected to the fifth node; and
a fifth transistor configured to supply an initialization voltage to the fifth node according to the second control signal,
wherein a light emission of the OLED is controlled according to a difference voltage between the high-level source voltage and the data voltage, and
wherein, when the second to fifth transistors are turned on and the first transistor is turned off, the initialization voltage is applied to the fifth node, the first and second nodes are connected to each other, the fourth and fifth nodes are connected to each other, and the third and fourth nodes are connected to each other.
2. The OLED display device of claim 1 , wherein the first transistor is turned on by the scan signal applied through a scan line, the second and fourth transistors are turned on by the first control signal applied through a first control line, and the third and fifth transistors are turned on by the second control signal applied through a second control line.
3. The OLED display device of claim 1 , wherein the second control signal is supplied to a gate electrode of the fifth transistor, and the initialization voltage is supplied to a source electrode of the fifth transistor.
4. The OLED display device of claim 1 , wherein, when the first, third and fifth transistors are turned on and the second and fourth transistors are turned off, the data voltage is applied to the first node, the initialization voltage is applied to the fifth node, and the third and fourth nodes are connected to each other.
5. The OLED display device of claim 4 , wherein a voltage of the third node is a voltage equal to the sum of a high-level source voltage and the threshold voltage of the driving transistor.
6. The OLED display device of claim 4 , wherein, when the second and fourth transistors are turned on and the first, third and fifth transistors are turned off, the first and second nodes are connected to each other, and the fourth and fifth nodes are connected to each other, and the OLED emits light.
7. A method of driving an organic light emitting diode (OLED) display device which includes first to fifth transistors, a driving transistor, a capacitor, and an OLED, the method comprising:
performing an operation in which, while the second to fifth transistors are turned on and the first transistor is turned off, a second node, supplied with a high-level source voltage, corresponding to a source electrode of the driving transistor is connected to a first node corresponding to one end of the capacitor, a third node corresponding to the other end of the capacitor and also simultaneously corresponding to a gate electrode of the driving transistor is connected to a fourth node corresponding to a drain electrode of the driving transistor, the fourth node is connected to a fifth node corresponding to an anode electrode of the OLED, and an initialization voltage supplied to the fifth transistor is applied to the fifth node;
performing an operation in which, while the first, third and fifth transistors are turned on and the second and fourth transistors are turned off, a data voltage supplied to the first transistor is applied to the first node, the initialization voltage is applied to the fifth node, and the third and fourth nodes are connected to each other; and
performing an operation in which, while the second and fourth transistors are turned on and the first, third and fifth transistors are turned off, the first and second nodes are connected to each other, and the fourth and fifth nodes are connected to each other, and the OLED emits light according to a difference voltage between the high-level source voltage and data voltage.
8. The method according to claim 7 , wherein the first transistor is turned on by a scan signal applied through a scan line, the second and fourth transistors are turned on by a first control signal applied through a first control line, and the third and fifth transistors are turned on by a second control signal applied through a second control line.