Organic light emitting diode display device for improving initialization characteristics and method of driving the same
AssigneeLG Display Co., Ltd.
InventorsJung-Min Lee, Jae-Ho Sim
Life of this patent
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Abstract
An organic light emitting diode (OLED) display device and a method of driving the same are provided. A time point at which each of transistors is turned on is controlled without using an additional transistor so that a node connected to a source electrode of a driver transistor can be floated, and a node connected to a gate electrode of the driver transistor can be initialized to an initialization voltage level. Thus, initialization characteristics can be improved to enhance degradation of response characteristics and luminance, and a threshold voltage of the driver transistor and occurrence of a ripple at a high-potential voltage terminal can be compensated.
Claims27
An organic light emitting diode (OLED) display device comprising:
- a first transistor connected to a high-potential voltage terminal and a second node;
- a switching transistor connected to a data line and the second node;
- a second transistor directly connected to a drain electrode of a driver transistor and a first node;
- an emission control transistor connected to the drain electrode of the driver transistor and one electrode of an OLED;
- a third transistor connected to the one electrode of the OLED and configured to reduce a voltage applied to the one electrode of the OLED;
- and
- a first capacitor connected between the high-potential voltage terminal and the first node,
- wherein the second transistor and the third transistor simultaneously turn on in response to a sensing signal applied through a sensing line and the emission control transistor turns on in response to an emission control signal applied through an emission line so that a reference voltage lower than a high-potential voltage at the high-potential voltage terminal is applied to the first node to initialize the first node, and
- wherein the first transistor and the switching transistor are turned off during an initialization period by electrically decoupling the high-potential voltage terminal and the data line from the driver transistor.
A method of driving an organic light emitting diode (OLED) display device including a switching transistor, a driver transistor, an emission control transistor, a first transistor, a second transistor, a third transistor, a first capacitor, a second capacitor, and an OLED, the method comprising:
- initializing, during an initialization period, a first node to which a gate electrode of the driver transistor is connected, by turning on the second transistor directly connected to a drain electrode of the driver transistor and the first node, the third transistor and the emission control transistor so that a reference voltage lower than a high-potential voltage at a high-potential voltage terminal is applied to the first node, and by turning off the first transistor and the switching transistor, to electrically decouple the high-potential voltage terminal and a data line from the driver transistor;
- sensing a threshold voltage of the driver transistor, and transmitting a data voltage to the first node during turn-on operations of the switching transistor, the second
- transistor and the third transistor;
- and
- allowing the OLED to emit light during a turn-on operation of the emission control transistor, according to the driver transistor driving the OLED.
An organic light emitting diode (OLED) display device comprising:
- a substrate having a pixel;
- and
- an organic light emitting diode (OLED) on the substrate,
- wherein the pixel comprises:
- a switching transistor connected to a scan line;
- a driver transistor connected to a data line to drive the OLED;
- an emission control transistor to control emission of the OLED;
- first and second capacitors to store charges;
- and
- a first transistor, a second transistor, and a third transistor to transfer signals to the driver transistor, the second transistor directly connected to a drain electrode of the driver transistor and a first node,
- wherein the second transistor and the third transistor simultaneously turn on in response to a sensing signal applied through a sensing line and the emission control transistor turns on in response to an emission control signal applied through an emission line so that a reference voltage is applied to the first node to initialize the first node, and
- wherein the first transistor and the switching transistor are turned off during an initialization period by electrically decoupling a high-potential voltage terminal and the data line from the driver transistor.
An apparatus comprising:
- a pixel circuit comprising a six-transistor-two-capacitor (6T2C) structure including a switching transistor, a driver transistor, an emission control transistor, a first transistor, a second transistor, a third transistor, and a first node to which a gate electrode of the driver transistor is connected, during an initialization period, the second transistor directly connected to a drain electrode of the driver transistor and the first node, the emission control transistor and the second transistor and the third transistor to be simultaneously turned on so that a reference voltage lower than a high-potential voltage at a high-potential voltage terminal is applied to the first node to initialize the first node, and the switching transistor and the first transistor to be simultaneously turned off during the initialization period to reduce a current through the driver transistor by electrically decoupling the high-potential voltage terminal and a data line from the driver transistor.
Dependencies are inferred from the claim text.