KR102122448B1 - Organic light emitting display device and method for driving thereof - Google Patents

Abstract

The present invention relates to an organic light emitting display device capable of compensating for a threshold voltage of a switching transistor included in a pixel and a driving method thereof, wherein the organic light emitting display device according to the present invention includes an organic light emitting device and a current flowing through the organic light emitting device Supplying a data voltage to a driving transistor for controlling the driving transistor, a first node serving as a gate electrode of the driving transistor, and a voltage supplied to a reference line to a second node between the organic light emitting device and the driving transistor A display panel having a plurality of pixels including a second switching transistor; And a panel driver driving the plurality of pixels in a sensing mode or a display mode. In the sensing mode, the panel driver fixes a voltage level of a first gate high voltage supplied to a gate electrode of the second switching transistor. In addition, while changing the voltage level of the second gate high voltage supplied to the gate electrode of the first switching transistor in units of frames, the threshold voltage of the first switching transistor included in the corresponding pixel is sensed through the reference line of each pixel. It is characterized by.

Description

Organic light-emitting display device and driving method therefor{ORGANIC LIGHT EMITTING DISPLAY DEVICE AND METHOD FOR DRIVING THEREOF}

The present invention relates to an organic light emitting display device and a driving method thereof.

Recently, the importance of a flat panel display device has increased with the development of multimedia. In response to this, flat panel display devices such as liquid crystal display devices, plasma display devices, and organic light emitting display devices have been commercialized. Among these flat panel display devices, the organic light emitting display device has attracted attention as a next-generation flat panel display device because it has a high-speed response speed, low power consumption, and has no problem in viewing angle because of its own light emission.

1 is a circuit diagram illustrating a pixel structure of a general organic light emitting display device.

Referring to FIG. 1, a pixel P of a typical organic light emitting diode display includes a switching transistor Tsw, a driving transistor Tdr, a capacitor Cst, and an organic light emitting diode OLED.

The switching transistor Tsw is switched according to the scan pulse SP supplied to the scan line SL to supply the data voltage Vdata supplied to the data line DL to the driving transistor Tdr. The driving transistor Tdr is switched according to the data voltage Vdata supplied from the switching transistor Tsw, and receives the data current Ioled flowing from the driving power EVdd supplied from the driving power line to the organic light emitting diode OLED. Control. The capacitor Cst is connected between the gate terminal and the source terminal of the driving transistor Tdr to store a voltage corresponding to the data voltage Vdata supplied to the gate terminal of the driving transistor Tdr, and the driving transistor is stored at the stored voltage. Turn on (Tdr). The organic light emitting diode OLED is electrically connected between the source terminal of the driving transistor Tdr and the cathode line EVss to emit light by the data current Ioled supplied from the driving transistor Tdr. Each pixel P of the general organic light emitting display device controls the size of the data current Ioled flowing through the organic light emitting diode OLED by switching the driving transistor Tdr according to the data voltage Vdata, and thus emits organic light. By emitting the device OLED, a predetermined image is displayed.

In such a general organic light emitting display device, a threshold voltage (Vth)/mobility characteristic of the driving transistor Tdr is different according to the position of the organic light emitting display panel according to the non-uniformity of the manufacturing process of the thin film transistor. . Accordingly, even if the same data voltage Vdata is applied to the driving transistor Tdr of each pixel P in a general organic light emitting diode display, uniform image quality cannot be achieved due to variations in current flowing through the organic light emitting diode OLED. There is a problem.

In order to solve this problem, the organic light emitting display device of Korean Patent Publication No. 10-2012-0076215 (hereinafter referred to as "prior art document") adds a sensor transistor to each pixel, and a switching transistor and a sensor transistor Disclosed is an external compensation technique for compensating the threshold voltage of the driving transistor by sensing the threshold voltage of the driving transistor through a reference line connected to the sensor transistor using switching of.

However, although the threshold voltage of the driving transistor Tdr can be compensated through an external compensation technique in the organic light emitting diode display of the prior art document, the threshold voltage of the switching transistor due to voltage stress due to driving at a high temperature for a long time ( Vth) / mobility (Mobility) as the characteristics change, there is a problem that the luminance decreases, thereby reducing the life. That is, the switching transistor included in the pixel of the prior art document serves to supply the data voltage to the gate electrode of the driving transistor. When the threshold voltage of the switching transistor is changed, the driving transistor according to the change amount of the threshold voltage of the switching transistor Since the gate-source voltage of is changed, the desired data voltage cannot be supplied to the gate electrode of the driving transistor.

Accordingly, there is a need for a method capable of sensing and compensating for a threshold voltage (Vth)/mobility characteristic of a switching transistor included in each pixel.

The present invention has been devised to solve the above-mentioned problems, and an object of the present invention is to provide an organic light emitting display device and a driving method thereof to compensate for a threshold voltage of a switching transistor included in a pixel.

In addition, another technical problem of the present invention is to provide an organic light emitting display device and a driving method thereof that can simultaneously compensate for threshold voltages of a driving transistor and a switching transistor included in a pixel.

In addition to the technical problems of the present invention mentioned above, other features and advantages of the present invention are described below, or it will be clearly understood by those skilled in the art from the description and description.

The organic light emitting display device according to the present invention for achieving the above-described technical problem is to supply a data voltage to the organic light emitting element, a driving transistor for controlling the current flowing through the organic light emitting element, a first node that is the gate electrode of the driving transistor A display panel having a plurality of pixels including a first switching transistor and a second switching transistor supplying a voltage supplied to a reference line to a second node between the organic light emitting element and the driving transistor; And a panel driver driving the plurality of pixels in a sensing mode or a display mode. In the sensing mode, the panel driver fixes a voltage level of a first gate high voltage supplied to a gate electrode of the second switching transistor. In addition, while changing the voltage level of the second gate high voltage supplied to the gate electrode of the first switching transistor in units of frames, the threshold voltage of the first switching transistor included in the corresponding pixel is sensed through the reference line of each pixel. It is characterized by.

The panel driver is characterized in that the voltage level of the second gate high voltage is incrementally increased by a predetermined voltage level for each frame unit.

The panel driver senses the voltage of the reference line for each frame unit to generate sensing data of each frame, and calculates a threshold voltage of the first switching transistor included in each pixel based on the sensing data of each frame. It is characterized by.

In the sensing mode, the panel driving unit includes the driving transistor included in the corresponding pixel through the reference line of each pixel while operating the driving transistor in a saturation driving mode through switching of the first and second switching transistors. It is characterized in that the threshold voltage is sensed and stored in the memory unit.

The driving method of the organic light emitting diode display according to the present invention for achieving the above-described technical problem is an organic light emitting element, a driving transistor for controlling a current flowing through the organic light emitting element, and a data voltage at a first node as a gate electrode of the driving transistor Driving of the organic light emitting display device including a plurality of pixels having a first switching transistor supplying a voltage and a second switching transistor supplying a voltage supplied to a reference line to a second node between the organic light emitting element and the driving transistor. A method comprising: (A) driving each of the plurality of pixels in a sensing mode; And driving (B) each of the plurality of pixels in a display mode, wherein (A) fixes the voltage level of the first gate high voltage supplied to the gate electrode of the second switching transistor, and the Sensing the threshold voltage of the first switching transistor included in the pixel through the reference line of each pixel while varying the voltage level of the second gate high voltage supplied to the gate electrode of the first switching transistor in frame units. It can be made including.

In the step (A), the voltage level of the second gate high voltage may be increased step by step for each frame unit by a set voltage level.

The step (A) comprises the step of generating the sensing data of each frame by sensing the voltage of the reference line for each frame unit (A1); And calculating a threshold voltage of the first switching transistor included in each pixel based on the sensing data of each frame (A2).

The step (A) is a threshold voltage of a driving transistor included in a corresponding pixel through the reference line of each pixel while operating the driving transistor in a saturation driving mode through switching of the first and second switching transistors It may further include the step of sensing and storing in the memory unit.

According to the solution means of the said subject, this invention has the following effects.

First, by changing the gate high voltage of the scan pulse that switches the switching transistor, which serves to transfer the data voltage to the driving transistor, the change in the characteristics of the switching transistor can be sensed by using the change in the voltage transfer rate of the switching transistor.

Second, by optimizing the gate high voltage of the scan pulse based on the change in the characteristics of the switching transistor sensed by the sensing mode, a decrease in the voltage transfer rate due to the change in the threshold voltage of the switching transistor is prevented, thereby enabling the high temperature long time of the organic light emitting display device. Reliability and lifespan according to driving can be secured.

Third, it is possible to compensate for changes in characteristics of the driving transistor and the switching transistor at the same time by sensing the characteristic changes of the driving transistor and the switching transistor included in each pixel and optimizing the gate high voltage of the data and scan pulse based on this.

1 is a circuit diagram illustrating a pixel structure of a general organic light emitting display device.
2 is a view for explaining an organic light emitting display device according to an exemplary embodiment of the present invention.
3 is a diagram schematically showing a structure of each pixel illustrated in FIG. 2.
FIG. 4 is a block diagram illustrating a column driver illustrated in FIG. 2.
5 is a diagram for describing a pixel operation in a first sensing mode in an organic light emitting diode display according to an exemplary embodiment of the present invention.
6 is a driving waveform diagram of a first sensing mode in an organic light emitting diode display according to an exemplary embodiment of the present invention.
7 is a diagram for describing a pixel operation in a second sensing mode in an organic light emitting diode display according to an exemplary embodiment of the present invention.
8 is a driving waveform diagram of a second sensing mode in an organic light emitting diode display according to an exemplary embodiment of the present invention.
9 is a simulation waveform diagram in which the sensing voltage according to the variation of the second gate high voltage is measured in the present invention.
10 is a driving waveform diagram in a display mode in an organic light emitting diode display according to an exemplary embodiment of the present invention.

The meaning of the terms described in this specification should be understood as follows.

It should be understood that a singular expression includes a plurality of expressions unless the context clearly defines otherwise, and the terms "first", "second", etc. are intended to distinguish one component from another component, The scope of rights should not be limited by these terms.

It should be understood that terms such as “include” or “have” do not preclude the existence or addition possibility of one or more other features or numbers, steps, actions, components, parts or combinations thereof.

Hereinafter, preferred embodiments of the organic light emitting display device and the driving method according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram for describing an organic light emitting diode display according to an exemplary embodiment of the present invention, and FIG. 3 is a diagram schematically showing the structure of each pixel illustrated in FIG. 2.

2 and 3, an organic light emitting diode display according to an exemplary embodiment of the present invention includes a display panel 100 and a panel driver 200.

The display panel 100 includes first to m (but m is a natural number) scan control lines SL1 to SLm, first to m sensing control lines SSL1 to SSLm, and first to n (however, n is a natural number greater than m) data lines DL1 to DLn, first to nth reference lines RL1 to RLn, first to nth driving power supply lines PL1 to PLn, cathode electrodes (not shown), and It includes a plurality of pixels (P).

Each of the first to mth scan control lines SL1 to SLm is formed side by side to have a constant interval along a first direction, that is, a horizontal direction, of the display panel 100.

Each of the first to mth sensing control lines SSL1 to SSLm is formed at regular intervals to be parallel to each of the scan control lines SL1 to SLm.

The first to nth data lines DL1 to DLn cross the scan control lines SL1 to SLm and the sensing control lines SSL1 to SSLm, respectively, in the second direction of the display panel 100, that is, It is formed side by side to have a constant spacing along the longitudinal direction.

Each of the first to n-th reference lines RL1 to RLn is formed at regular intervals to be parallel to each of the data lines DL1 to DLn.

Each of the first to nth driving power lines PL1 to PLn is formed at regular intervals to be parallel to each of the data lines DL1 to DLn. Here, each of the first to nth driving power lines PL1 to PLn may be formed at regular intervals to be parallel to each of the scan control lines SL1 to SLm. Each of the first to nth driving power lines PL1 to PLn may be commonly connected to a driving power common line CPL formed on an upper side and/or a lower side of the display panel 100.

The cathode electrode may be formed as a passage on the entire surface of the display panel 100 or may be formed at regular intervals to be parallel to each of the data lines DL1 to DLn or the scan control lines SL1 to SLm. have.

Each of the plurality of pixels P is formed for each pixel area defined by each of the first to mth scan control lines SL1 to SLm and each of the first to nth data lines DL1 to DLn that cross each other. do. Here, each of the plurality of pixels P may be any one of a red pixel, a green pixel, a blue pixel, and a white pixel. One unit pixel displaying one image may include adjacent red pixels, green pixels, blue pixels, and white pixels, or may include red pixels, green pixels, and blue pixels.

Each of the plurality of pixels P may include a first switching transistor Tsw1, a second switching transistor Tsw2, a driving transistor Tdr, a capacitor Cst, and an organic light emitting diode OLED. Here, the transistors Tsw1, Tsw2, and Tdr may be a-Si TFT, poly-Si TFT, oxide TFT, or organic TFT as a thin film transistor (TFT).

The first switching transistor Tsw1 is switched by the first scan pulse SP1 to output a data voltage Vdata supplied to the data line DL. To this end, the first switching transistor Tsw1 includes a gate electrode connected to an adjacent scan control line SCL, a source electrode connected to an adjacent data line DL, and a first node that is a gate electrode of the driving transistor Tdr ( n1).

The second switching transistor Tsw2 is switched by the second scan pulse SP2 to supply a voltage Vref or Vpre supplied to the reference line RL as a second node n2 that is a source electrode of the driving transistor Tdr. To supply. To this end, the second switching transistor Tsw2 includes a gate electrode connected to the adjacent sensing control line SSCL, a source electrode connected to the adjacent reference line RL, and a drain electrode connected to the second node n2.

The capacitor Cst includes a gate electrode and a source electrode of the driving transistor Tdr, that is, first and second electrodes connected between the first and second nodes n1 and n2. The first electrode of the capacitor Cst is connected to the first node n1, and the second electrode of the capacitor Cst is connected to the second node n2. The capacitor Cst charges after charging the difference voltage of the voltage supplied to each of the first and second nodes n1 and n2 according to the switching of the first and second switching transistors Tsw1 and Tsw2, respectively. The driving transistor Tdr is switched according to the voltage applied.

The driving transistor Tdr is turned on by the voltage of the capacitor Cst to control the amount of current flowing from the driving power supply line PL to the organic light emitting diode OLED. To this end, the driving transistor Tdr includes a gate electrode connected to the first node n1, a source electrode connected to the second node n2, and a drain electrode connected to the driving power line PL.

The organic light emitting diode OLED emits light by the data current Ioled supplied from the driving transistor Tdr to emit monochromatic light having luminance corresponding to the data current Ioled. To this end, the organic light emitting device (OLED) is a first electrode (for example, an anode electrode) connected to the second node (n2), an organic layer (not shown) formed on the first electrode, and a second connected to the organic layer Electrodes (eg, cathode electrodes). At this time, the organic layer may be formed to have a structure of a hole transport layer/organic light emitting layer/electron transport layer or a structure of a hole injection layer/hole transport layer/organic light emitting layer/electron transport layer/electron injection layer. Furthermore, the organic layer may further include a functional layer for improving light emission efficiency and/or lifespan of the organic light emitting layer. In addition, the second electrode may be individually connected to each of the plurality of pixels P, or may be commonly connected to the plurality of pixels P, and low-potential power sources EVss are supplied to the second electrode.

The panel driver 200 drives the display panel 100 in a first sensing mode, a second sensing mode, or a display mode.

The first sensing mode may be defined as driving of the display panel 100 for sensing the threshold voltage of the driving transistor Tdr included in each pixel P, and the second sensing mode may include each pixel P It may be defined as driving of the display panel 100 for sensing the threshold voltage of the first switching transistor Tsw1 included in ). Here, the first and second sensing modes may be performed for each inspection process, a set period, a power-on/off timing of the organic light-emitting display device, or a user setting before shipment of the organic light-emitting display device.

The display mode includes the pixel data DATA whose threshold voltage of the driving transistor Tdr of each pixel P sensed by the sensing mode is compensated, and the first switching transistor Tsw1 of each pixel P. It may be defined as driving of the display panel 100 for displaying an image on each pixel P using a first scan pulse SP1 having a voltage level based on a threshold voltage.

In the first sensing mode, the panel driver 200 fixes the gate voltages of the first and second switching transistors Tsw1 and Tsw2 included in each pixel P to source the driving transistor Tdr. While operating in a follower mode, the source voltage of the driving transistor Tdr is sensed through the reference line RL to generate first sensing data Sdata_Tdr and based on the first sensing data Sdata_Tdr. The threshold voltage of the driving transistor Tdr of each pixel P is calculated and stored in a memory (not shown). In addition, in the first sensing mode, the panel driver 200 calculates a compensation value corresponding to a threshold voltage for the driving transistor Tdr of each pixel P stored in the memory, and calculates the compensation value and the memory. After calculating the compensation deviation value of the initial (or previous) compensation value for the driving transistor Tdr of each pixel P stored in the sub-212, the calculated compensation deviation value is the initial (or previous) compensation value Compensation data of each pixel P is added to or subtracted from and stored in the memory unit 212.

In the second sensing mode, the panel driving unit 200 fixes the gate voltage of the second switching transistor Tsw2 included in each pixel P, and the frame of the first switching transistor Tsw1 in units of frames. By varying the gate voltage stepwise, while operating the first switching transistor Tsw1 in a source follower mode, the source voltage of the driving transistor Tdr is sensed through the reference line RL, and the first switching transistor Tsw1 is sensed. The second sensing data Sdata_Tsw1 is generated, and the second sensing data Sdata_Tsw1 of each frame and the threshold voltage of the driving transistor Tdr of each pixel P stored in the memory unit 212 are generated. Threshold voltages for the first switching transistor Tsw1 of each pixel P are calculated and stored in a memory (not shown).

In the display mode, the panel driver 200 corrects input data of each pixel P based on compensation data of each pixel P stored in the memory unit 212 and corresponds to the corrected data. The first scan pulse SP1 having a voltage level set according to a threshold voltage of the first switching transistor Tsw1 stored in the memory unit 212 is supplied to the corresponding pixel P and is synchronized with the data voltage. It is supplied to the scan control line SL. The panel driver 200 may supply the second scan pulse SP2 having a reference voltage level to the sensing control line SSL at the same time as the first scan pulse SP1.

The panel driving unit 200 includes a timing control unit 210, a voltage supply unit 220, a row driving unit 230, and a column driving unit 240.

The timing control unit 210 may be configured to sense first and second threshold voltages (or mobility) of the driving transistor Tdr and the first switching transistor Tsw1 included in each pixel P at a user's set or set period. The row driver 230 and the column driver 240 are operated according to one of the second sensing modes. In addition, the timing controller 210 operates each of the row driver 230 and the column driver 240 according to a display mode for displaying an image on the display panel 100.

In the first or second sensing mode, the timing controller 210 operates the corresponding transistors Tdr and Tsw1 in a source follower mode to sense the threshold voltage of the corresponding transistors Tdr and Tsw1. For generating the pixel data DATA, control signals DCS, RCS1, RCS2 and scan pulse level data L1/L2/L3. For example, in the first sensing mode, the timing controller 210 senses pixel data DATA for sensing a threshold voltage of the driving transistor Tdr included in each pixel P of the display panel 100. And control signals DCS, RCS1, RCS2, and first scan pulse level data L1 for setting the voltage level of the first scan pulse SP1 to a reference high voltage level. In addition, in the second sensing mode, the timing controller 210 senses pixel data DATA for sensing a threshold voltage of the first switching transistor Tsw1 included in each pixel P of the display panel 100. And control signals DCS, RCS1, RCS2, and second scan pulse level data for stepwise varying the voltage level of the first scan pulse SP1 within a range lower than the reference high voltage level in frame units. (L2).

In the display mode, the timing control unit 210 stores the image data Idata of each pixel P input from an external driving system (or graphics card) in the memory unit 212. ) Compensates according to the compensation data to generate pixel data DATA of each pixel P, provides the generated pixel data DATA to the column driver 240, and an external driving system (or Graphic card) based on a timing synchronization signal (TSS) input from the row (row) driver 230 and the column (column) driver 240 for controlling each of the data control signal (DCS) and the first and the first 2 Generate low control signals (RCS1, RCS2).

In addition, the timing control unit 210 based on the threshold voltage of the first switching transistor Tsw1 included in each pixel P stored in the memory unit 212 is the voltage level of the first scan pulse SP1. The third scan pulse level data L3 for setting is generated. For example, the timing control unit 210 analyzes the threshold voltages of all the first switching transistors Tsw1 stored in the memory unit 212 to determine the maximum value, minimum value, average value, and average value of the upper values, Any one of the average value and the mode value of the lower values may be calculated as a compensation reference value, and third scan pulse level data L3 may be generated based on the calculated compensation reference value and provided to the above-described voltage supply unit 220.

In the first and second sensing modes and the display mode, the voltage supply unit 220 uses a first gate high voltage VGH and a reference low voltage level having a reference high voltage level using an input power Vin input from the outside. A gate low voltage VGL is generated, and the generated first gate high voltage VGH and the gate low voltage VGL are provided to the row driver 230.

In the first sensing mode, the voltage supply unit 220 digitally-analogizes the first scan pulse level data L1 supplied from the timing control unit 210 to a second gate high voltage having a reference high voltage level ( VGH') and provides it to the row driver 230.

In the second sensing mode, the voltage supply unit 220 digitally-analogizes the second scan pulse level data L2 supplied from the timing controller 210 to have a voltage level lower than a reference high voltage level. The second gate high voltage VGH', which is changed step by frame, is generated and provided to the row driver 230. For example, the voltage supply unit 220 increases the second gate high voltage VGH' which is stepwise increased by a set voltage such as 0.5V or 1V according to the second scan pulse level data L2 in units of frames. It can be generated and printed.

In the display mode, the voltage supply unit 220 converts the third scan pulse level data L3 supplied from the timing control unit 210 into digital-analog conversion and includes a first switching transistor included in each pixel P ( A second gate high voltage VGH' having a voltage level based on the threshold voltage of Tsw1) is generated and provided to the row driver 230. The voltage supply unit 220 may include a programmable voltage generator (not shown), and may generate the second gate high voltage VGH' through the programmable voltage generator.

The row driver 230 includes a first row control signal RCS1 supplied from the timing controller 210 and a gate low voltage VGL and a second gate high voltage supplied from the voltage supply unit 220 ( VGH') to generate first scan pulses SP1 that are sequentially supplied to the first to mth scan control lines SL1 to SLm. In addition, the row driving unit 230 includes a second row control signal RCS2 supplied from the timing controller 210 and a gate low voltage VGL and a first gate high supplied from the voltage supply unit 220. A second scan pulse SP2 that is sequentially supplied to the first to mth sensing control lines SSL1 to SSLm is generated using a voltage VGH. To this end, the row driving unit 230 according to an example includes a scan line driving unit 232 and a sensing line driving unit 234.

The scan line driver 232 is connected to one side and/or the other side of each of the first to mth scan control lines SL1 to SLm. The scan line driver 232 generates a first scan signal that is sequentially shifted based on the first row control signal RCS1, and the gate low voltage VGL and the second gate high voltage VGH'. ) To level shift the first scan signal with the first scan pulse SP1 to sequentially supply the first to mth scan control lines SL1 to SLm. For example, the scan line driver 232 may include a first shift register unit (not shown) that generates a first scan signal that is sequentially shifted based on the first row control signal RCS1, and the gate row voltage. Level shifting the first scan signal sequentially supplied from the first shift register unit using the (VGL) and the second gate high voltage (VGH') to the first scan pulse (SP1) to the first to It may include a first level shifting unit (not shown) to supply to the m-th scan control line (SL1 to SLm).

In the first sensing mode, the scan line driver 232 generates a first scan pulse SP1 of the second gate high voltage VGH' having a reference high voltage level to generate the first to mth scan control lines. (SL1 to SLm) will be sequentially supplied. In addition, in the second sensing mode, the scan line driver 232 has a voltage level lower than a reference high voltage level, but a first scan pulse of the second gate high voltage VGH', which is changed stepwise in frame units ( SP1) is generated and sequentially supplied to the first to mth scan control lines SL1 to SLm. In addition, in the display mode, the scan line driver 232 is the first of the second gate high voltage VGH' generated based on the threshold voltage of the first switching transistor Tsw1 included in each pixel P. The scan pulse SP1 is generated and sequentially supplied to the first to mth scan control lines SL1 to SLm.

The sensing line driver 234 is connected to one side and/or the other side of each of the first to mth sensing control lines SSL1 to SSLm, respectively. The sensing line driver 234 generates a second scan signal that is sequentially shifted based on the second row control signal RCS2, and the gate low voltage VGL and the first gate high voltage VGH. The second scan signal is level shifted with the second scan pulse SP2 to sequentially supply to the first to mth sensing control lines SSL1 to SSLm. For example, the sensing line driver 234 may include a second shift register unit (not shown) that generates a second scan signal that is sequentially shifted based on the second row control signal RCS2, and the gate row voltage. Levels of the second scan signal sequentially supplied from the second shift register unit by using the (VGL) and the first gate high voltage (VGH) are applied to the second scan pulse SP2 to perform the first to the first to m may include a second level shifting unit (not shown) that supplies the sensing control lines SSL1 to SSLm.

The column driver 240 is connected to the first to n-th data lines DL1 to DLn and the first to n-th reference lines RL1 to RLn to perform the first control according to the mode control of the timing controller 210. It operates in sensing mode, second sensing mode, or display mode.

In the first or second sensing mode, the column driving unit 240 is a reference line (in response to the data control signal (DCS) of the first or second sensing mode supplied from the timing control unit 210) The first or second sensing data (Sdata_Tdr/Sdata_Tsw1) is generated by sensing the source voltage of the driving transistor Tdr included in each pixel P through RL1 to RLn), and the generated first or second sensing data. (Sdata_Tdr/Sdata_Tsw1) is provided to the timing control unit 210. In addition, in the display mode, the column driver 240 responds to the data control signal DCS of the display mode supplied from the timing controller 210 to generate a data voltage Vdata in units of horizontal lines. The reference voltages Vref are supplied to the corresponding reference lines RL1 to RLn, respectively, while being supplied to the corresponding data lines DL1 to DLn. To this end, the column (column) driving unit 240, as shown in Figure 4, is configured to include a data driving unit 242, a switching unit 244, and a sensing unit 246.

The data driver 242 receives the pixel data DATA supplied from the timing controller 210 in response to the data control signal DCS supplied from the timing controller 210 according to the display mode or the sensing mode. It is converted to a data voltage and supplied to the first to nth data lines DL1 to DLn, respectively.

The switching unit 244 responds to the data control signal DCS supplied from the timing controller 210 according to the display mode, and sets the reference voltage Vref supplied from the outside to the first to nth reference lines RL1. To RLn), respectively. In addition, the switching unit 244 is a first to n-th reference to the pre-charging voltage (Vpre) supplied from the outside in response to the data control signal (DCS) supplied from the timing control unit 210 according to the sensing mode Each of the first to nth reference lines RL1 to RLn is initialized to a precharging voltage Vpre by supplying to the lines RL1 to RLn, respectively, and then each of the first to nth reference lines RL1 to RLn is sensed. Connect to the part 246. To this end, the switching unit 244 according to an example includes first to nth selector lines 244a to 244n connected to each of the first to nth reference lines RL1 to RLn and the sensing unit 246. The selectors 244a to 244n may be made of a multiplexer.

The sensing unit 246 is connected to the first to n-th reference lines RL1 to RLn through the switching unit 244 in the sensing mode, so that the voltages of the first to n-th reference lines RL1 to RLn are respectively applied. Sensing, the first or second sensing data (Sdata_Tdr/Sdata_Tsw1) corresponding to the sensed voltage is generated and provided to the timing controller 210. To this end, the sensing unit 246 includes first to nth analog-to-digital converters 246a to 246n connected to the first to nth reference lines RL1 to RLn through the switching unit 244. Can be configured.

5 is a diagram for describing a pixel operation in a first sensing mode in an organic light emitting display device according to an exemplary embodiment of the present invention, and FIG. 6 is a first in the organic light emitting display device according to an exemplary embodiment of the present invention It is a driving waveform diagram of sensing mode.

First, referring to FIGS. 2, 5, and 6, in the first sensing mode, each pixel P operates in the first to third periods t1, t2, and t3.

In the first sensing mode, the timing controller 120 generates sensing data DATA for sensing the threshold voltage of the driving transistor Tdr of each pixel P, and the column driver 240 Data control signal (DCS) for controlling each of the row driver 230 and the column driver 240 in a first sensing mode based on an input timing synchronization signal (TSS) And generate first and second row control signals RCS1 and RCS2. In addition, in the first sensing mode, the timing control unit 210 generates first scan pulse level data L1 for setting a reference high voltage level based on the gate high voltage of the first scan pulse SP1, and the voltage supply unit ( 220).

In the first sensing mode, the voltage supply unit 220 has a second gate high voltage VGH' having a reference high voltage level corresponding to the first scan pulse level data L1 supplied from the timing control unit 210. At the same time, the first gate high voltage VGH having a reference high voltage level and a gate low voltage VGL having a reference low voltage level are generated and provided to the row driver 230.

In the first sensing mode, the row driving unit 230 includes the first row control signal RCS1 and the second gate high voltage VGH' of the reference high voltage level supplied from the voltage supply unit 220. A first scan pulse SP1 is generated and supplied to the scan control line SL using a gate low voltage VGL having a reference low voltage level, and at the same time, the second low control signal RCS2 and the first gate high voltage VGH are generated. ) And the gate low voltage VGL to generate the second scan pulse SP2 and supply it to the sensing control line SSL.

In the first sensing mode, the column driver 240 is a sensing data voltage Vdata according to the driving of the data driver 243 based on the sensing pixel data DATA and the data control signal DCS. ) To the corresponding data line DL, and each pixel in a horizontal period unit through the reference line RL according to the driving of the switching unit 244 and the sensing unit 246 based on the data control signal DCS. The threshold voltage of the driving transistor Tdr included in (P) is sequentially sensed.

Hereinafter, a first sensing mode of the organic light emitting diode display according to the exemplary embodiment of the present invention will be described with reference to FIGS. 5 and 6.

In the first period t1, the first switching transistor Tsw1 is turned on by the first scan pulse SP1 of the second gate high voltage VGH' having the reference high voltage level to turn on the data line DL. The second scan pulse of the first gate high voltage VGH having the reference high voltage level, the sensing data voltage Vdata supplied to the first node n1 is supplied to the gate electrode of the driving transistor Tdr. The second switching transistor Tsw2 is turned on by SP2, and the pre-charging voltage Vpre supplied to the reference line RL is supplied to the second node n2, that is, the source electrode of the driving transistor Tdr. . At this time, the sensing data voltage Vdata has a target voltage level set to sense the threshold voltage of the driving transistor Tdr. Accordingly, during the first period t1, the source voltage of the driving transistor Tdr and the reference line RL are initialized to the pre-charging voltage Vpre.

Then, in the second period t2, each of the first and second switching transistors Tsw1 and Tsw2 is in a linear driving mode by the first gate high voltage VGH having the reference high voltage level. In the operating state, the reference line RL is switched to the floating state by the switching unit 244 of the column driver 240. Accordingly, the driving transistor Tdr operates in a saturation driving mode by the sensing data voltage Vdata, which is a bias voltage supplied to the gate electrode, thereby causing data to be transferred to the floating reference line RL. The difference voltage Vdata-Vth between the voltage Vdata and the threshold voltage Vth of the driving transistor Tdr is charged.

Then, in the third period t3, the second scan pulse SP2 of the gate low voltage VGL having a reference low voltage level while the turn-on state of the first switching transistor Tsw1 is maintained. Accordingly, the second switching transistor Tsw2 is turned off, and at the same time, the reference line RL is connected to the sensing unit 246 by the switching unit 244 of the column driving unit 240. Accordingly, the sensing unit 246 senses the voltage Vsense charged in the reference line RL, and converts the sensed voltage Vsense to analog-digital to generate the first sensing data Sdata_Tdr. Provided to the timing control unit 210.

Accordingly, the timing control unit 210 calculates the threshold voltage Vth_Tdr of the driving transistor Tdr based on the data voltage Vdata and the first sensing data Sdata_Tdr provided from the sensing unit 246. , The calculated threshold voltage Vth_Tdr of the driving transistor Tdr is stored in the memory unit 212. In this case, the threshold voltage Vth_Tdr of the driving transistor Tdr may be a voltage Vdata-Vsense minus the sensing voltage Vsense of the sensing unit 246 from the data voltage Vdata.

7 is a diagram for explaining a pixel operation in a second sensing mode in an organic light emitting display device according to an embodiment of the present invention, and FIG. 8 is a second light in the organic light emitting display device according to an embodiment of the present invention It is a driving waveform diagram of sensing mode.

First, referring to FIGS. 2, 7, and 8, in the second sensing mode, each pixel P is first to first for each of the first to i-th frames (Frame[1] to Frame[i]). It operates in three periods (t1, t2, t3).

In the second sensing mode, the timing controller 120 generates sensing data DATA for sensing the threshold voltage of the first switching transistor Tsw1 of each pixel P to generate the column driver ( Data control signal for controlling each of the row driver 230 and the column driver 240 in a first sensing mode based on an input timing synchronization signal (TSS). DCS) and the first and second row control signals RCS1 and RCS2. In addition, in the second sensing mode, the timing controller 210 generates second scan pulse level data L2 for varying the gate high voltage of the first scan pulse SP1 in units of frames, and supplies the voltage to the voltage supply unit 220. ).

In the second sensing mode, the voltage supply unit 220 generates a second gate high voltage VGH' having a voltage level corresponding to the second scan pulse level data L1 supplied from the timing control unit 210. The first gate high voltage (VGH) having a reference high voltage level and a gate low voltage (VGL) having a reference low voltage level are generated and provided to the row driver 230 at the same time as being generated in units of frames.

In the second sensing mode, the row driver 230 includes the first row control signal RCS1 and the second gate high voltage VGH' supplied in units of frames from the voltage supply unit 220. The first scan pulse SP1 is generated and supplied to the scan control line SL using the gate low voltage VGL having a reference low voltage level, and the second low control signal RCS2 and the first gate high voltage VGH are generated. ) And the gate low voltage VGL to generate the second scan pulse SP2 and supply it to the sensing control line SSL.

In the second sensing mode, the column driver 240 is a data voltage Vdata according to the driving of the data driver 243 based on the sensing pixel data DATA and the data control signal DCS. Converted and supplied to the corresponding data line DL, and each pixel in a horizontal period unit through the reference line RL according to the driving of the switching unit 244 and the sensing unit 246 based on the data control signal DCS The source voltage of the driving transistor Tdr included in (P) is sequentially sensed.

Hereinafter, a third sensing mode of the organic light emitting diode display according to the exemplary embodiment of the present invention will be described with reference to FIGS. 7 and 8.

First, in the first frame (Frame[1]) of the second sensing mode, in the first period t1, the second gate high voltage VGH' having a first voltage level lower than the reference high voltage level The first switching transistor Tsw1 is turned on by the first scan pulse SP1 and the sensing data voltage Vdata supplied to the data line DL is the first node n1, that is, the driving transistor Tdr. The second switching transistor Tsw2 is turned on by the second scan pulse SP2 of the first gate high voltage VGH having the reference high voltage level and is supplied to the reference line RL. The pre-charging voltage Vpre is supplied to the second node n2, that is, the source electrode of the driving transistor Tdr. At this time, the sensing data voltage Vdata has a target voltage level set to sense the threshold voltage of the driving transistor Tdr. Accordingly, during the first period t1, the source voltage of the driving transistor Tdr and the reference line RL are initialized to the pre-charging voltage Vpre.

Then, in the second period t2, the turn-on state of the second switching transistor Tsw2 is maintained, and the gate voltage of the first switching transistor Tsw1 is the first voltage level of the bias voltage. As the two gate high voltages VGH' are fixed, the driving transistor Tdr is turned on by the sensing data voltage Vdata. At the same time, the reference line RL is switched to the floating state by the switching unit 244 of the column driver 240. Accordingly, the first switching transistor Tsw1 operates in the saturation driving mode by the second gate high voltage VGH' of the first voltage level supplied to the gate electrode, thereby causing the reference line in the floating state ( The difference voltage Vdata-Vth between the data voltage Vdata and the threshold voltage Vth of the driving transistor Tdr is charged in the RL.

Then, in the third period T3, the second scan pulse SP2 of the gate low voltage VGL having the reference low voltage level while the turn-on state of the first switching transistor Tsw1 is maintained. Accordingly, the second switching transistor Tsw2 is turned off, and at the same time, the reference line RL is connected to the sensing unit 246 by the switching unit 244 of the column driving unit 240. Accordingly, the sensing unit 246 senses the voltage Vsense charged in the reference line RL, and converts the sensed voltage Vsense to analog-digital conversion to obtain the first frame (Frame[1]). The second sensing data Sdata_Tsw2 is generated and provided to the timing controller 210. The timing control unit 210 stores the second sensing data Sdata_Tsw2 of the first frame Frame[1] provided from the sensing unit 246 in the memory unit 212 or an internal register.

In the second frame (Frame[2]) of the second sensing mode, the second gate high voltage VGH' having a second voltage level lower than the reference high voltage level and higher than the first voltage level is obtained. Except for supplying the 1 scan pulse SP1 to the gate electrode of the first switching transistor Tsw1, the first to third sections t1 of the second frame (Frame[2]) of the second sensing mode described above are Since it is the same as t2, t3), a duplicate description thereof will be omitted.

In the second frame (Frame[2]) of the second sensing mode, the saturation driving mode is performed by the second gate high voltage VGH' of the second voltage level at which the first switching transistor Tsw1 is supplied to the gate electrode. By operating as, the voltage Vdata-Vth charged in the floating reference line RL is higher than the voltage Vdata-Vth charged in the reference line RL in the second frame Frame[2]. do. That is, when the gate voltage of the first switching transistor Tsw1 increases, the transmission rate of the sensing data voltage Vdata_sen transferred to the gate electrode of the driving transistor Tdr increases, thereby causing the source of the driving transistor Tdr. As the voltage increases, the voltage Vdata-Vth charged in the reference line RL also increases. In the second frame (Frame[2]) of the second sensing mode, the sensing unit 246 senses the voltage Vsense charged in the reference line RL and analogizes the sensed voltage Vsense. By digitally converting, the second sensing data Sdata_Tsw2 of the second frame (Frame[1]) is generated and provided to the timing controller 210, and the timing controller 210 is provided with the second sensing data 246 from the sensing unit 246. The second sensing data Sdata_Tsw2 of the two frames Frame[2] is stored in the memory unit 212 or an internal register.

In each of the third to i-th frames of the second sensing mode, the first switching transistor Tsw1 is changed by varying the second gate high voltage VGH' of the first scan pulse SP1 to be increased stepwise. The second sensing data Sdata_Tsw2 of each frame is generated by sensing the voltage Vdata-Vth charged in the reference line RL while operating in the saturation driving mode. In addition, the timing controller 210 stores the second sensing data Sdata_Tsw2 of each frame in the memory unit 212 or an internal register.

Meanwhile, the timing control unit 210 controls the voltage level of the second gate high voltage VGH' to be variable for each frame of the second sensing mode, while controlling the current frames received from the sensing unit 246. By comparing and analyzing the second sensing data Sdata_Tsw2 of each pixel P with respect to the second sensing data Sdata_Tsw2 of each pixel P with respect to the previous frame stored in the memory unit 212 or an internal register The second gate high voltage VGH' corresponding to the second sensing data Sdata_Tsw2 having the same value is detected. Then, the timing controller 210 determines the threshold voltage Vth_Tdr of the driving transistor Tdr of the corresponding pixel P stored in the memory unit 212 from the detected second gate high voltage VGH'. The subtraction (-) operation is performed, and the operation result (Vth_Tsw1-Vth_Tdr) is calculated as a threshold voltage (Vth_Tsw1) of the first switching transistor Tsw1 and stored in the memory unit 212.

In this second sensing mode, the present invention operates the first switching transistor Tsw1 in a saturation driving mode, while the second gate high voltage VGH' is changed stepwise to the reference line RL. The process of sensing the charged voltage (Vdata-Vth) is repeated over the first to i-th frames (Frame[1] to Frame[i]), and as illustrated in FIG. 9, the sensing voltage at each frame ( The threshold voltage Vth_Tsw1 of the first switching transistor Tsw1 is detected based on the voltage level of the second gate high voltage VGH' in which Vsenses are saturated. Here, FIG. 9 is a simulation waveform diagram measuring the sensing voltage Vsense according to the variation of the second gate high voltage VGH'. As a result, the present invention is based on the change in the sensing voltage Vsense due to the voltage transfer rate difference of the first switching transistor Tsw1 according to the variation of the second gate high voltage VGH', the first switching transistor Tsw1. The threshold voltage Vth_Tsw1 of is detected.

10 is a driving waveform diagram in a display mode in an organic light emitting diode display according to an exemplary embodiment of the present invention.

First, referring to FIGS. 2, 4, and 10, in the display mode, each pixel P operates in an addressing period DM_t1 and a light emitting period DM_t2.

In the display mode, the timing control unit 120 compensates data of the driving transistor Tdr of each pixel P that stores the input image data Idata of each pixel P in the memory unit 212. Correction according to the pixel data DATA of each pixel P is generated, the generated pixel data DATA is provided to the column driver 240, and is based on an input timing synchronization signal TSS. To generate the data control signal DCS and the first and second row control signals RCS1 and RCS2 for controlling each of the row driver 230 and the column driver 240 in a display mode. do. In addition, in the display mode, the timing control part 210 is the first scan pulse SP1 based on the threshold voltage of the first switching transistor Tsw1 of each pixel P stored in the memory part 212. The third scan pulse level data L3 for setting the voltage level of is generated and provided to the voltage supply unit 220.

In the display mode, the voltage supply unit 220 generates a second gate high voltage VGH' having a voltage level corresponding to the third scan pulse level data L3 supplied from the timing control unit 210. At the same time, a first gate high voltage VGH having a reference high voltage level and a gate low voltage VGL having a reference low voltage level are generated and provided to the row driver 230.

In the display mode, the row driving unit 230 has a gate having a first low control signal RCS1 and a second gate high voltage VGH' supplied from the voltage supply unit 220 and a reference low voltage level. The first scan pulse SP1 is generated and supplied to the scan control line SL using the low voltage VGL, and the second low control signal RCS2, the first gate high voltage VGH, and the gate low are generated. The second scan pulse SP2 is generated using the voltage VGL and supplied to the sensing control line SSL.

In the display mode, the column driver 240 converts the data to a data voltage Vdata according to the driving of the data driver 243 based on the pixel data DATA and the data control signal DCS. The voltage is supplied to the line DL, and the reference voltage Vref is supplied to the reference line RL according to the driving of the switching unit 244 based on the data control signal DCS.

Hereinafter, a display mode of an organic light emitting diode display according to an exemplary embodiment will be described with reference to FIGS. 3 and 10.

First, in the addressing period DM_t1, the first scan pulse SP1 of the second gate high voltage VGH' having a voltage level set based on the threshold voltage of the first switching transistor Tsw1 of the corresponding pixel P ), the first switching transistor Tsw1 is turned on, and the data voltage Vdata supplied to the data line DL is supplied to the first node n1, that is, the gate electrode of the driving transistor Tdr, and is referenced. The second switching transistor Tsw2 is turned on by the second scan pulse SP2 of the first gate high voltage VGH having the high voltage level, so that the reference voltage Vref supplied to the reference line RL is second. It is supplied to the node n2, that is, the source electrode of the driving transistor Tdr. Accordingly, the capacitor Cst connected to the first node n1 and the second node n2 is charged with the difference voltage Vdata-Vref between the data voltage Vdata and the reference voltage Vref. Here, since the first switching transistor Tsw1 is turned on by the second gate high voltage VGH' reflecting the amount of change in its threshold voltage, the data voltage Vdata of the first switching transistor Tsw1 is It is transmitted to the gate electrode of the driving transistor Tdr without being affected by the threshold voltage change. In addition, the data voltage Vdata charged in the capacitor Cst includes a compensation voltage for compensating the threshold voltage of the corresponding driving transistor Tdr.

Then, in the light emission period DM_t2, the first and second switching transistors Tsw1 and Tsw2 by the first and second scan pulses SP1 and SP2 of the gate low voltage VGL having the reference low voltage level, respectively. Are each turned off. Accordingly, the driving transistor Tdr is turned on by the voltage Vdata-Vref stored in the capacitor Cst. Accordingly, the data current Ioled determined by the difference voltage Vdata-Vref between the data voltage Vdata and the reference voltage Vref by the turned-on driving transistor Tdr is an organic light emitting diode OLED. ), the organic light emitting diode (OLED) emits light in proportion to the data current (Ioled) flowing from the driving power supply line (PL) to the second electrode (or cathode electrode). That is, in the light emission period DM_t2, when the first and second switching transistors Tsw1 and Tsw2 are turned off, a current flows through the driving transistor Tdr, and the organic light emitting diode OLED is proportional to the current. The voltage of the second node n2 rises while starting light emission, and the voltage of the first node n1 increases by the voltage of the second node n2 by the capacitor Cst, thereby increasing the voltage of the capacitor Cst. The gate-source voltage Vgs of the driving transistor Tdr is continuously maintained by the voltage so that the organic light emitting diode OLED continues to emit light until the addressing period DM_t1 of the next frame. Here, the current Ioled flowing through the organic light emitting diode OLED is not affected by a change in the threshold voltage of the corresponding driving transistor Tdr by the data voltage Vdata including the compensation voltage.

As described above, the present invention is a characteristic of the driving transistor Tdr by sensing the change in the voltage transfer rate of the first switching transistor Tsw1 included in each pixel P by varying the gate high voltage of the first scan pulse SP1. The threshold voltage of the first switching transistor Tsw1 included in each pixel P may be sensed regardless of the change.

In addition, the present invention is based on the threshold voltage of the first switching transistor Tsw1 sensed by the sensing mode to optimize the gate high voltage of the first scan pulse SP1 to change the threshold voltage of the first switching transistor Tsw1. Accordingly, it is possible to prevent a decrease in the voltage transmission rate, thereby securing reliability and lifespan due to high-temperature long-time driving of the organic light emitting display device.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes are possible without departing from the technical details of the present invention. It will be clear to those who have the knowledge of Therefore, the scope of the present invention is indicated by the following claims, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts should be interpreted to be included in the scope of the present invention.

100: display panel 210: timing control
220: power supply 230: row (row) drive
232: scan line driver 234: sensing line driver
240: row driving unit 242: data driving unit
244: switching unit 246: sensing unit

Claims (14)

An organic light emitting device, a driving transistor controlling a current flowing through the organic light emitting device, a first switching transistor supplying a data voltage to a first node as a gate electrode of the driving transistor, and a voltage supplied to a reference line are applied to the organic light emitting device And a second switching transistor that supplies a second node between the driving transistor and the second node. And
And a panel driver driving the plurality of pixels in a sensing mode or a display mode,
In the sensing mode, the panel driver fixes the voltage level of the first gate high voltage supplied to the gate electrode of the second switching transistor, and the voltage of the second gate high voltage supplied to the gate electrode of the first switching transistor. The organic light emitting display device of claim 1, wherein the threshold voltage of the first switching transistor included in the corresponding pixel is sensed through the reference line of each pixel while varying the level in units of frames. According to claim 1,
The panel driving unit increases the voltage level of the second gate high voltage for each frame unit step by step by a set voltage level. According to claim 2,
The panel driver generates sensing data of each frame by sensing the voltage of the reference line for each frame unit, and calculates a threshold voltage of the first switching transistor included in each pixel based on the sensing data of each frame. An organic light emitting display device, characterized in that. The method of claim 3,
In the sensing mode, the panel driver operates the driving transistor in a saturation driving mode through switching of the first and second switching transistors, and includes driving transistors included in the corresponding pixel through the reference line of each pixel. An organic light emitting display device, characterized in that sensing the threshold voltage and storing it in the memory unit. The method of claim 4,
The panel driving unit,
The second gate high voltage corresponding to the sensing data having the same value is detected by analyzing the sensing data of each frame in each pixel unit,
The threshold voltage of the first switching transistor is detected and stored in the memory unit according to the detected second gate high voltage of each pixel and the threshold voltage of the driving transistor of the corresponding pixel stored in the memory unit. Organic light emitting display device. The method of claim 4,
In the display mode, the panel driving unit corrects data to be supplied to each pixel based on a threshold voltage of a driving transistor of each pixel stored in the memory unit. The method according to claim 5 or 6,
In the display mode, the panel driving unit sets the voltage level of the second gate high voltage based on the threshold voltage of the first switching transistor of each pixel stored in the memory unit. An organic light emitting device, a driving transistor controlling a current flowing through the organic light emitting device, a first switching transistor supplying a data voltage to a first node as a gate electrode of the driving transistor, and a voltage supplied to a reference line are applied to the organic light emitting device In the driving method of the organic light emitting display device comprising a plurality of pixels having a second switching transistor to supply a second node between the and the driving transistor,
Driving each of the plurality of pixels in a sensing mode (A); And
And driving each of the plurality of pixels in a display mode (B),
The step (A) fixes the voltage level of the first gate high voltage supplied to the gate electrode of the second switching transistor, and frames the voltage level of the second gate high voltage supplied to the gate electrode of the first switching transistor. And sensing a threshold voltage of the first switching transistor included in the corresponding pixel through the reference line of each pixel while varying in units. The method of claim 8,
In the step (A), the voltage level of the second gate high voltage is increased step by step in units of the frame by a set voltage level. The method of claim 9,
The step (A),
Sensing the voltage of the reference line for each frame unit to generate sensing data of each frame (A1); And
And calculating a threshold voltage of the first switching transistor included in each pixel based on the sensing data of each frame (A2). The method of claim 10,
The step (A) is a threshold voltage of a driving transistor included in a corresponding pixel through the reference line of each pixel while operating the driving transistor in a saturation driving mode through switching of the first and second switching transistors And sensing and storing in the memory unit. The method of claim 11,
The step (A2),
Analyzing the sensing data of each frame in each pixel unit and detecting the second gate high voltage corresponding to the sensing data having the same value; And
And detecting the threshold voltage of the first switching transistor according to the detected second gate high voltage of each pixel and the threshold voltage of the driving transistor of the corresponding pixel stored in the memory unit and storing the threshold voltage of the first switching transistor. Method of driving an organic light emitting display device, characterized in that made by. The method of claim 12,
The step (B) comprises a step of correcting data to be supplied to each pixel based on a threshold voltage of a driving transistor of each pixel stored in the memory unit. The method of claim 12 or 13,
The step (B) further comprises setting the voltage level of the second gate high voltage based on the threshold voltage of the first switching transistor of each pixel stored in the memory unit. Method of driving the display device.

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