Organic light emitting diode (OLED) display and driving method thereof
Provided is an organic light emitting diode (OLED) display which includes a driving circuit and pixels arranged on pixel rows. In a (j−1)-th horizontal period, the driving circuit samples a threshold voltage of a driving Transistor (DT) of each pixel arranged on the (j−1)-th pixel row, and initializes a voltage of a gate electrode of a driving TFT of each pixel arranged on the j-th pixel row. In addition, in a j-th horizontal period, the driving circuit samples a threshold voltage of the driving TFT of each pixel arranged on the j-th pixel row.
1. An organic light emitting diode (OLED) display comprising:
a display panel in which a plurality of pixels arranged on n number of pixel rows including a j-th pixel row, wherein n and j are integers and j is equal to or smaller than n, first to second scan lines connected to pixels in each pixel row, an emission line, a reference voltage line, and a data line are arranged; and
a driving circuit comprising a gate driver that supplies a scan signal to each pixel row through the first and second scan lines respectively, and that supplies an emission signal to the emission line and a data driver that supplies data voltages to the data line,
wherein each of the plurality of pixels comprises:
a driving Transistor (DT) including a gate electrode connected to a node A, a source electrode connected to a node B, and a drain electrode connected to a high-potential driving voltage input terminal;
a first transistor connected to the node A and a node B, and capable of being turned on turned on by the first scan signal received through the first scan line;
a second transistor connected to the node B and a node C connected to an anode electrode of an OLED, and capable of being turned on by the emission signal received through the emission line;
a third transistor connected to the node C and the reference voltage line, and capable of being turned on by the first scan signal;
a fourth transistor connected to the node D and the reference voltage line, and capable of being turned on by the emission signal;
a fifth transistor connected to the node D and the data line, and capable of being turned on by the second scan signal received through the second scan line; and
a storage capacitor including a first electrode connected to the node A, and a second electrode connected to a node D; and
wherein, in a (j−1)-th horizontal period during which the scan signal is supplied to a (j−1)-th pixel row, the driving circuit samples a threshold voltage of the driving transistor in each pixel arranged on the (j−1)-th pixel row, and initializes a voltage of the gate electrode of the driving transistor in each pixel arranged on the j-th pixel row.
2. The OLED display of claim 1 , wherein, in a j-th horizontal period during which the scan signal is supplied to the j-th pixel row, the data driver supplies the data voltage to pixels arranged on the j-th pixel row.
3. An organic light emitting diode (OLED) display comprising:
a display panel in which a plurality of pixels arranged on n number of pixel rows including a j-th pixel row, wherein n and j are integers and j is equal to or smaller than n, first to second scan lines connected to pixels in each pixel row, an emission line, a reference voltage line, and a data line are arranged;
a gate driver that supplies first and second scan signals to the first and second scan lines, respectively, and that supplies an emission signal to the emission line; and
a data driver that supplies a data voltage to the data line,
wherein each of the plurality of pixels comprises:
a driving Transistor (DT) including a gate electrode connected to a node A, a source electrode connected to a node B, and a drain electrode connected to a high-potential driving voltage input terminal;
a first transistor connected to the node A and a node B, and capable of being turned on turned on by the first scan signal received through the first scan line;
a second transistor connected to the node B and a node C connected to an anode electrode of an OLED, and capable of being turned on by the emission signal received through the emission line;
a third transistor connected to the node C and the reference voltage line, and capable of being turned on by the first scan signal;
a fourth transistor connected to the node D and the reference voltage line, and capable of being turned on by the emission signal;
a fifth transistor connected to the node D and the data line, and capable of being turned on by the second scan signal received through the second scan line; and
a storage capacitor including a first electrode connected to the node A, and a second electrode connected to a node D.
4. The OLED display of claim 3 , wherein:
in a (j−1)-th horizontal period during which the first scan signal is supplied to a (j−1)-th pixel row,
a fourth transistor of each pixel arranged on the j-th pixel row initializes the node D in accordance with the emission signal, and
first and third transistors of each pixel arranged on the j-th pixel row are turned on by the first scan signal, and a second transistor of each pixel arranged on the j-th pixel row is turned on by the emission signal, so that the node A is initialized to a reference voltage.
5. The OLED display of claim 4 , wherein:
in a j-th horizontal period during which the first scan signal is supplied to the j-th pixel row,
the first transistor of each pixel arranged on the j-th pixel row is turned on by the first scan signal and thereby establishes a diode connection of the nodes A and B, so that the node A is charged to a high-potential driving voltage which is supplied from the high-potential driving voltage input terminal.
6. The OLED display of claim 5 , wherein, in the j-th horizontal period, a fifth transistor of each pixel arranged on the j-th pixel row is turned on by the second scan signal, so that the node D is charged to the data voltage.
7. The OLED display of claim 6 , wherein, in a (j+1)-th horizontal period during which the first scan signal is supplied to a (j+1)-th pixel row, the fourth transistor of each pixel arranged on the j-th pixel row is turned on by the emission signal, so that the nodes D is charged to the reference voltage.
8. The OLED display of claim 7 ,
wherein, in the (j+1)-th horizontal period, the second transistor of each pixel arranged on the j-th pixel row connects the nodes B and C in response to the emission signal, and
wherein the OLED emits a light with a voltage variance of the node D being reflected to the node A when the j-th horizontal period proceeds into the (j+1)-th horizontal period.
9. The OLED display of claim 3 , wherein at least one of the second to fifth transistors has a double-gate structure.
10. A driving method of an organic light emitting diode (OLED) display comprising: a display panel in which a plurality of pixels arranged on n number of pixel rows including a j-th pixel row, wherein n and j are integers and j is equal to or smaller than n, first to second scan lines connected to pixels in each pixel row, an emission line, a reference voltage line, and a data line are arranged; a gate driver that supplies first and second scan signals to the first and second scan lines, respectively, and that supplies an emission signal to the emission line; and a data driver that supplies a data voltage to the data line, wherein each of the plurality of pixels comprises: a driving Transistor (DT) including a gate electrode connected to a node A, a source electrode connected to a node B, and a drain electrode connected to a high-potential driving voltage input terminal; a first transistor connected to the node A and a node B, and capable of being turned on turned on by the first scan signal received through the first scan line; a second transistor connected to the node B and a node C connected to an anode electrode of an OLED, and capable of being turned on by the emission signal received through the emission line; a third transistor connected to the node C and the reference voltage line, and capable of being turned on by the first scan signal; a fourth transistor connected to the node D and the reference voltage line, and capable of being turned on by the emission signal; a fifth transistor connected to the node D and the data line, and capable of being turned on by the second scan signal received through the second scan line; and a storage capacitor including a first electrode connected to the node A, and a second electrode connected to a node D, the driving method comprising:
in a (j−1)-th horizontal period during which a scan signal is supplied to a (j−1)-th pixel row through its first scan line, a threshold voltage of a driving thin film transistor (TFT) of each pixel arranged on the (j−1)-th pixel row is sampled, and a voltage of a gate electrode of a driving TFT of each pixel arranged on the j-th pixel row is initialized;
in a j-th horizontal period during which the scan signal is supplied to the j-th pixel row through its first scan line, a threshold voltage of the driving TFT of each pixel arranged on the j-th pixel row is sampled, and a data voltage is charged in each pixel arranged on the j-th pixel row; and
in a (j+1)-th horizontal period during which the scan signal is supplied to a (j+1)-th pixel row through its first scan line, an OLED in each pixel arranged on the j-th pixel row is caused to emit a light according to the data voltage charged.