KR102120124B1 - Organic light emitting display device - Google Patents

Abstract

The present invention provides an organic light emitting display device capable of sensing a threshold voltage of a switching transistor included in a pixel. The organic light emitting display device according to the present invention includes a first switching transistor, a second switching transistor, a driving transistor, and A display panel including a plurality of pixels having an organic light emitting element; A column driver configured to sense the threshold voltage of one of the driving transistors and the first and second switching transistors included in each pixel through the reference line to generate sensing data; And a timing control unit that changes at least one of a high voltage and a low voltage of each of the first and second scan pulses based on the sensing data.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device capable of compensating for a threshold voltage of a transistor included in a pixel.

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 uses a switching of the driving transistor Tdr according to the data voltage Vdata, and the data current Ioled flowing from the driving power supply EVdd to the organic light emitting diode OLED is used. By controlling the size, the organic light emitting device (OLED) emits light to display a predetermined image.

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 in the case of a general organic light emitting display device, even when the same data voltage Vdata is applied to the driving transistor Tdr for each pixel P, it is impossible to implement a uniform image quality due to variations in current flowing through the organic light emitting diode OLED. There is this.

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 switching transistor and the sensor transistor are each due to voltage stress due to long driving. As the threshold voltage (Vth) / mobility (Mobility) characteristics change, there is a problem that the luminance decreases, thereby reducing the life. That is, since 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 desired data voltage can be supplied to the gate electrode of the driving transistor. There will be no. In addition, since the sensor transistor included in each pixel of the prior art document serves to initialize the voltage of the source electrode of the driving transistor, when the threshold voltage of the sensor transistor is changed, the source voltage of the driving transistor can be initialized to a desired level. There will be no.

2A is a graph showing a current flowing through an organic light emitting device with respect to a data voltage according to a change in threshold voltage of a sensor transistor, and FIG. 2B is a graph showing a deviation of a data voltage according to a change in threshold voltage of a sensor transistor to be.

2A and 2B, it can be seen that as the threshold voltage Vth of the sensor transistor is positively shifted, the current flowing through the organic light emitting device for each of the data voltages Vdata1 to Vdata9 decreases. have. In addition, it can be seen that the higher the voltage level of the data voltages Vdata1 to Vdata9 is, the higher the deviation (ㅿVdata) of the data voltage is due to the change in the threshold voltage Vth of the sensor transistor.

As a result, in the prior art literature, a luminance variation for each pixel is generated due to a variation in the threshold voltage (Vth) of the sensor transistor for each pixel as well as a variation in the threshold voltage (Vth) of the driving transistor for each pixel, and thus there is a problem that image quality deteriorates. .

The present invention has been made to solve the above-mentioned problems, and it is a technical problem to provide an organic light emitting display device capable of sensing a threshold voltage of a switching transistor included in a pixel.

Another object of the present invention is to provide an organic light emitting display device capable of compensating for a threshold voltage of a switching transistor included in a pixel.

Further, another object of the present invention is to provide an organic light emitting display device capable of improving image quality degradation due to a threshold voltage variation of each of the driving transistor and the switching transistor included in the 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 diode display according to the present invention for achieving the above technical problem is supplied to a first switching transistor and a sensing control line that output a data voltage supplied to a data line according to a first scan pulse supplied to a scan control line A second switching transistor outputting a reference voltage supplied to a reference line according to a second scan pulse, a driving transistor outputting a data current corresponding to a difference voltage between the data voltage and the reference voltage, and emitting light by the data current A display panel including a plurality of pixels having an organic light emitting element; In the sensing mode, the sensing voltage is sensed by supplying the data voltage to the data line and sensing threshold voltages of any one of the driving transistor and the first and second switching transistors included in each pixel through the reference line. Column driving unit for generating a; In the display mode, the pixel data corresponding to the image data is supplied to the column driver, and at least one of the high voltage and the low voltage of each of the first and second scan pulses is variable based on the sensing data. A timing control unit generating first and second scan pulse level data; The first high voltage and the first low voltage of the first scan pulse are generated based on the first scan pulse level data, and the second high voltage of the second scan pulse is based on the second scan pulse level data. And a voltage supply unit generating a second low voltage; And generating the first scan pulse using the first high voltage and the first low voltage and supplying the first scan pulse to the scan control line, and generating the second scan pulse using the second high voltage and the second low voltage. In addition, a row driver may be supplied to the sensing control line.

In the sensing mode, the timing controller generates the first and second scan pulse level data for operating one of the driving transistor and the first and second switching transistors in a source follower mode. Can be.

The timing control unit may calculate a compensation reference value based on sensing data of all pixels formed on the display panel, and generate the first and second scan pulse level data based on the calculated compensation reference value.

The timing control unit includes a scan pulse level data generation unit, and the scan pulse level data generation unit is a driving time calculation unit for calculating a driving time of the first or second switching transistor; And a threshold voltage change amount corresponding to the calculated driving time of the first or second switching transistor based on the sensing data of the first or second switching transistor, and the first threshold voltage change amount. And a scan pulse level setting unit generating second scan pulse level data.

The scan pulse level setting unit uses a relational expression for deriving a change in threshold voltage of the first or second switching transistor with respect to the driving time of the first or second switching transistor, or the first or second with respect to the driving time The threshold voltage variation may be calculated using a look-up table in which the threshold voltage variation of the switching transistor is mapped.

The organic light emitting diode display according to the present invention for achieving the above technical problem is supplied to a first switching transistor and a sensing control line that output a data voltage supplied to a data line according to a first scan pulse supplied to a scan control line A second switching transistor outputting a reference voltage supplied to a reference line according to a second scan pulse, a driving transistor outputting a data current corresponding to a difference voltage between the data voltage and the reference voltage, and emitting light by the data current A display panel including a plurality of pixels having an organic light emitting element; A timing control unit controlling the plurality of pixels in a sensing mode or a display mode; In response to control of the timing controller according to the sensing mode, the first scan pulse for driving the first switching transistor to be driven in a linear driving mode is generated and supplied to the scan control line, and at the same time, the second switching transistor is saturated. A row driver generating the second scan pulse for driving in a driving mode and supplying the second scan pulse to the sensing control line; And in response to control of the timing controller according to the sensing mode, supply a sensing data voltage to the data line, and sense the threshold voltage of the second switching transistor through the reference line to generate sensing data. It may include a column driver provided to the control unit.

The timing controller calculates a threshold voltage of the second switching transistor by subtracting and calculating a voltage corresponding to the sensing data from a high voltage of the second scan pulse, and based on the threshold voltage of the second switching transistor. The voltage level of the scan pulse can be varied.

The column driver responds to the control of the timing controller according to the sensing mode, supplies a sensing data voltage to the data line, and senses threshold data by sensing a threshold voltage of the driving transistor through the reference line. It can be generated and additionally provided to the timing controller.

In the display mode, the timing control unit corrects input data based on a threshold voltage of the driving transistor sensed by the sensing mode and a threshold voltage of the second switching transistor to generate pixel data, and generates the column data. The driver may convert the pixel data into a data voltage in response to control of the timing controller according to the display mode and supply the data to the data line.

The timing control unit firstly corrects image data based on a threshold voltage of the driving transistor to generate correction data, and secondly corrects the correction data based on the threshold voltage of the second switching transistor and the correction data to perform the correction. Pixel data can be generated.

The timing controller extracts a threshold voltage of the second switching transistor and a coefficient of a quadratic equation corresponding to the correction data from a look-up table, and calculates a quadratic equation using the extracted coefficient of the quadratic equation and the correction data The correction data is second-corrected to generate the pixel data, and the look-up table includes a first order coefficient and a second coefficient of the second variable of the second equation set for each correction data for each threshold voltage of the second switching transistor. The coefficient of the variable and the coefficient of the 0th order variable may be mapped.

The timing control unit extracts a threshold voltage of the second switching transistor and a characteristic compensation value corresponding to the correction data from a look-up table, and performs the second correction on the correction data using the extracted characteristic compensation value to obtain the pixel data. The characteristic compensation value preset for each correction data may be mapped to each threshold voltage of the second switching transistor in the look-up table.

The scan control line and the sensing control line are electrically connected to each other, and the first scan pulse or the second scan pulse may be supplied to the scan control line and the sensing control line connected to each other.

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

First, the threshold voltage of the switching transistor included in each pixel may be sensed by supplying different scan pulses to the switching transistor included in the pixel.

Second, the threshold voltage of the driving transistor for each pixel is sensed, and the threshold voltage of the switching transistor is compensated by varying the voltage level of the scan pulse supplied to the switching transistor included in each pixel based on the sensed threshold voltage of the driving transistor, Through this, it is possible to prevent a decrease in luminance due to a change in the threshold voltage of the switching transistor and to extend the life.

Third, the threshold voltage of the switching transistor for each pixel is sensed, and the voltage level of the scan pulse supplied to the switching transistor is varied according to the threshold voltage variation according to the driving time of the switching transistor based on the sensed threshold voltage of the switching transistor. The voltage stress can be reduced to extend the life.

Fourth, the threshold voltages of the driving transistors and the second switching transistors for each pixel are sensed, and the data voltages are corrected based on the threshold voltages of the sensed driving transistors and the second switching transistors. Due to the threshold voltage variation of the second switching transistor for each pixel, luminance variation for each pixel may be minimized, thereby improving image quality.

1 is a circuit diagram illustrating a pixel structure of a general organic light emitting display device.
2A is a graph showing a current flowing through an organic light emitting device with respect to a data voltage according to a threshold voltage change amount of a sensor transistor in a prior art document.
2B is a graph showing variations in data voltage according to a threshold voltage change amount of a sensor transistor in a prior art document.
3 is a view for explaining an organic light emitting display device according to a first example of the present invention.
4 is a diagram schematically showing the structure of each pixel illustrated in FIG. 3.
FIG. 5 is a block diagram illustrating a column driver shown in FIG. 2.
6 is a diagram schematically showing an organic light emitting display device according to a first example of the present invention.
7 is a driving waveform diagram in a sensing mode in the organic light emitting diode display according to the first example of the present invention.
8 is a driving waveform diagram in a display mode in an organic light emitting diode display according to a first example of the present invention.
9A to 9D are graphs for explaining a variation of a high voltage and a low voltage of a scan pulse in the organic light emitting diode display according to the first example of the present invention.
10 is a diagram schematically showing an organic light emitting display device according to a second example of the present invention.
11 is a driving waveform diagram in a sensing mode in the organic light emitting diode display according to the second example of the present invention.
12 is a diagram schematically showing an organic light emitting display device according to a third example of the present invention.
13 is a driving waveform diagram in a sensing mode in an organic light emitting diode display according to a third example of the present invention.
14 is a driving waveform diagram in a sensing mode in a modified example of the organic light emitting diode display according to the third example of the present invention.
15 is a block diagram illustrating an example of a timing controller for generating scan pulse level data in the organic light emitting diode display according to the second or third example of the present invention.
16 is a block diagram illustrating another example of a timing control unit for generating scan pulse level data in the organic light emitting diode display according to the second or third example of the present invention.
17 is a block diagram illustrating a timing control unit of an organic light emitting diode display according to a fourth example of the present invention.
18 is a flowchart illustrating a method of driving an organic light emitting diode display according to a first example of the present invention.
19 is a flowchart illustrating a method of driving an organic light emitting display device according to a second or third example of the present invention.
20 is a flowchart illustrating a method of driving an organic light emitting display device according to a fourth example of the present invention.
21A is a diagram illustrating a histogram of a threshold voltage map and a threshold voltage level of a driving transistor for each pixel sensed by a sensing mode according to the present invention.
21B is a diagram illustrating a histogram of a threshold voltage map and a threshold voltage level of the second switching transistor for each pixel sensed by the sensing mode according to the present invention.
22 is a graph showing variations in data voltage according to a threshold voltage change amount of the second switching transistor in the organic light emitting diode display according to the fourth example 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. It should be understood that the term “at least one” includes all possible combinations from one or more related items. For example, the meaning of "at least one of the first item, the second item, and the third item" means 2 of the first item, second item, or third item, as well as the first item, second item, and third item, respectively Any combination of items that can be presented from more than one dog.

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

3 is a diagram for describing an organic light emitting diode display according to a first example of the present invention, and FIG. 4 is a diagram schematically showing a structure of each pixel illustrated in FIG. 3.

3 and 4, an organic light emitting display device according to a first example of the present invention includes a display panel 110, a timing control unit 120, a voltage supply unit 130, a row driver 140, and It includes a column (column) driving unit 150.

The display panel 110 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 nth (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 at regular intervals along a first direction of the display panel 110, that is, a horizontal direction.

Each of the first to mth sensing control lines SSL1 to SSLm is formed at regular intervals in parallel with 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 110, that is, It is formed side by side at regular intervals along the longitudinal direction.

Each of the first to n-th reference lines RL1 to RLn is formed at regular intervals in parallel with each of the data lines L1 to DLn.

Each of the first to nth driving power lines PL1 to PLn is formed at regular intervals in parallel with each of the data lines DL1 to DLn. Each of the first to nth driving power lines PL1 to PLn may be commonly connected to a driving power common line CPL formed in upper and/or lower non-display areas of the display panel 110. Optionally, each of the first to nth driving power lines PL1 to PLn may be formed at regular intervals parallel to each of the scan control lines SL1 to SLm, in which case the driving power common line ( CPL) may be formed on the left and/or right non-display areas of the display panel 110.

The cathode electrode may be formed in a passage on the entire surface of the display panel 110 or may be formed in a line shape parallel to each of the data lines DL1 to DLn or the scan control lines SL1 to SLm. have.

Each of the plurality of sub-pixels P 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 intersecting each other. Is formed. Here, each of the plurality of sub-pixels P may be any one of a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel. One unit pixel displaying one image may include adjacent red sub-pixels, green sub-pixels, blue sub-pixels, and white sub-pixels, or may include red, green, 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 is a gate electrode connected to an adjacent scan control line SCL, a first electrode connected to an adjacent data line DL, and a first node that is a gate electrode of the driving transistor Tdr. and a second electrode connected to (n1). Here, the first and second electrodes of the first switching transistor Tsw1 may be a source electrode or a drain electrode according to the direction of the current.

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 an adjacent sensing control line SSL, a first electrode connected to an adjacent reference line RL, and a second electrode connected to a second node n2. do. Here, the first and second electrodes of the second switching transistor Tsw2 may be a source electrode or a drain electrode according to the direction of the current.

The capacitor Cst includes first and second electrodes connected between the gate electrode and the source electrode of the driving transistor Tdr, that is, 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 voltage 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 voltage 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 timing control unit 120 may have a threshold voltage (or mobility) of one of the first switching transistor Tsw1, the second switching transistor Tsw2, and the driving transistor Tdr for each pixel P at a user's setting or set period. ), the row driver 140 and the column driver 150 are operated in a sensing mode according to a sensing mode for sensing. In addition, the timing control unit 120 operates the row driving unit 140 and the column driving unit 150 in a display mode in a display section for displaying an image on the display panel 110. In addition, the timing control unit 120 has high voltages VGH1 and VGH2 and low voltages VGL1 of the first and second scan pulses SP1 and SP2 according to the display mode or the sensing mode. , VGL2) generate first and second scan pulse level data SPLD1 and SPLD2 for setting each voltage level.

In the sensing mode, the timing control unit 120 operates the corresponding transistor in a source follower mode according to the sensing mode, thereby controlling pixel data DATA and a control signal for sensing a threshold voltage of the corresponding transistor Tdr. A first for generating (DCS, RCS1, RCS2) and setting the voltage levels of the high voltages (VGH1, VGH2) and low voltages (VGL1, VGL2) of the first and second scan pulses (SP1, SP2). And second scan pulse level data SPLD1, SPLD2. For example, the timing controller 120 according to the first example controls and controls pixel data DATA for sensing the threshold voltage of the driving transistor Tdr for each pixel P of the display panel 110 based on the sensing mode. In addition to generating the signals DCS, RCS1 and RCS2, first and second scan pulse level data SPLD1 and SPLD2 are generated. The timing controller 120 according to the second example may include pixel data DATA and control signals for sensing the threshold voltage of the first switching transistor Tsw1 for each pixel P of the display panel 110 based on the sensing mode. DCS, RCS1, RCS2) are generated, and first and second scan pulse level data SPLD1, SPLD2 are generated. The timing controller 120 according to the third example may include pixel data DATA and control signals for sensing the threshold voltage of the second switching transistor Tsw2 for each pixel P of the display panel 110 based on the sensing mode. DCS, RCS1, RCS2) are generated, and first and second scan pulse level data SPLD1, SPLD2 are generated. The timing controller 120 according to the fourth example is configured to sequentially sense threshold voltages of the driving transistors Tdr and the second switching transistors Tsw2 for each pixel P of the display panel 110 based on the sensing mode. The pixel data DATA and the control signals DCS, RCS1 and RCS2 are generated, and the first and second scan pulse level data SPLD1 and SPLD2 are generated.

In the display mode, the timing control unit 120 according to the first example arranges image data Idata input from an external driving system (or graphics card) to match the driving of the display panel 110, thereby pixel data. (DATA) is generated, the generated pixel data (DATA) is provided to the column driver 150, and based on a timing synchronization signal (TSS) input from an external drive system (or graphics card). Data control signals DCS and first and second row control signals RCS1 and RCS2 are generated to control each of the row driver 140 and the column driver 150. At the same time, the timing controller 120 according to the first example may sense data Sdata or display panel 110 of a pixel P included in a horizontal line group including at least one horizontal line of the display panel 110. Based on the sensing data Sdata of all the pixels P formed in ), one of the maximum value, the minimum value, the average value, the average value of the upper values, and the average value of the lower values is calculated as a compensation reference value, and calculated. Based on the compensation reference value, at least one of the high voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2 of the first and second scan pulses SP1 and SP2 every frame or at least one horizontal line. First and second scan pulse level data SPLD1 and SPLD2 for varying levels may be generated.

In the display mode, the timing controller 120 according to the second example generates compensation data for each pixel P based on sensing data Sdata for each pixel P sensed by the sensing mode, and compensates the compensation. The pixel data DATA is corrected according to data and provided to the column driver 150, and the data control signal DCS and the first and second row control signals RCS1 and RCS2 are generated. At the same time, based on the compensation reference value, the first and the first and second voltage levels for varying at least one of the high voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2 of the first and second scan pulses SP1 and SP2. 2 scan pulse level data SPLD1 and SPLD2 may be generated.

In the display mode, the timing controller 120 according to the third example provides the pixel data DATA to which the compensation data is reflected or not, to the column driver 150, and to the compensation reference value. First and second scan pulse level data for varying the voltage level of at least one of the high voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2 of the first and second scan pulses SP1 and SP2 based on the (SPLD1, SPLD2) can be generated.

In the display mode, the timing control unit 120 according to the fourth example is driven based on sensing data Sdata of the first and/or second switching transistors Tsw1 and Tsw2 sensed by the sensing mode. According to the driving time of the first and/or second switching transistors Tsw1, Tsw2 using a relational expression for calculating a change in the threshold voltage of the switching transistor over time or a look-up table to which a characteristic compensation value for the driving time is mapped First and second scan pulse level data SPLD1 and SPLD2 for varying the voltage level of at least one of the high voltages VGH1 and VGH2 of the first and second scan pulses SP1 and SP2 and the low voltages VGL1 and VGL2. ).

In the display mode, the timing controller 120 according to the fifth example calculates and calculates a characteristic compensation value for each pixel based on the sensing data Sdata of the driving transistor Tdr for each pixel sensed by the sensing mode. The pixel-specific characteristic compensation value is reflected in the pixel-specific image data (Idata) to generate pixel-specific correction data (DATA) and provides it to the column driver 150, and the first and second scan pulses SP1 , First and second scan pulse level data SPLD1 and SPLD2 for setting the high voltages VGH1 and VGH2 of SP2 and the low voltages VGL1 and VGL2 as reference voltage levels, respectively.

The voltage supply unit 130 separately generates each of the first high voltage VGH1 and the first low voltage VGL1 of the first scan pulse SP1 based on the first scan pulse level data SPLD1. At the same time, each of the second high voltage VGH2 and the second low voltage VGL2 of the second scan pulse SP2 is individually generated based on the second scan pulse level data SPLD2. The voltage supply unit 130 according to an example converts each of the first and second scan pulse level data SPLD1 and SPLD2 into digital-analog and converts the first high voltage VGH1 and the first low voltage VGL1, The second high voltage VGH2 and the fourth low voltage VGL2 may include four programmable voltage generators (not shown) that individually generate each. The voltage supply unit 130 according to another example includes a pulse width modulator (not shown) that generates a pulse width modulated signal based on each of the first and second scan pulse level data SPLD1 and SPLD2, and a pulse width modulated signal The first high voltage VGH1, the first low voltage VGL1, the second high voltage VGH2, and the second low voltage VGL2, respectively, are individually generated from the input power source Vin. It may include four DC-DC converters (not shown).

In the display mode, the voltage supply unit 130 according to the first example is the first high voltage VGH1 of the reference high voltage level based on the first scan pulse level data SPLD1 supplied from the timing control unit 120. ) And the first low voltage VGL1 of the reference low voltage level, respectively, and the second high voltage VGH2 and the reference low voltage level of the reference high voltage level based on the second scan pulse level data SPLD2. Each of the second row voltages VGL2 may be generated and provided to the row driver 140. In this case, the timing control unit 120 may not generate the first and second scan pulse level data SPLD1 and SPLD2, and accordingly, the voltage supply unit 130 may first and second scan pulse levels The first and second high voltages VGH1 and VGH2 of the set reference high voltage level and the first and second low voltages VGL1 and VGL2 of the reference low voltage level are generated, respectively, without data SPLD1 and SPLD2 to generate the low. (row) can be provided to the driving unit 140.

In the display mode, the voltage supply unit 130 according to the second example is the first high voltage of the reference high voltage level based on the first scan pulse level data SPLD1 supplied from the timing control unit 120 ( VGH1) and the second scan supplied from the timing controller 120 at the same time while varying the voltage level of at least one of the first row voltage VGL1 of the reference low voltage level and providing it to the row driver 140. The row driver is configured to vary at least one voltage level of the second high voltage VGH2 of the reference high voltage level and the second low voltage VGL2 of the reference low voltage level based on pulse level data SPLD2. (140).

The row driving unit 140 includes a first row control signal RCS1 supplied from the timing controller 120 and a first high voltage VGH1 and a first row voltage supplied from the voltage supply unit 130 ( VGL1) sequentially generates first scan pulses SP1 and sequentially supplies the first to mth scan control lines SL1 to SLm. In addition, the row driving unit 140 includes a second row control signal RCS2 supplied from the timing control unit 120 and a second high voltage VGH2 and a second row supplied from the voltage supply unit 130. The second scan pulse SP2 is sequentially generated based on the voltage VGL2 and sequentially supplied to the first to mth sensing control lines SSL1 to SSLm. Here, each of the row control signals RCS1 and RCS2 may include a start signal and a plurality of clock signals.

The row driver 140 according to an example includes a scan line driver 142 and a sensing line driver 144.

The scan line driver 142 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 142 generates a first scan signal that is sequentially shifted based on the first row control signal RCS1, and generates the first high voltage VGH1 and the first low voltage VGL1. The first scan signal is level shifted with a first scan pulse SP1 to sequentially supply to the first to mth scan control lines SL1 to SLm. For example, the scan line driver 142 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 first high The first to mth scan control lines by level shifting the first scan signal sequentially supplied from the first shift register unit using the voltage VGH1 and the first low voltage VGL1 to the first scan pulse It may be made to include a first level shifting unit (not shown) to supply to (SL1 to SLm).

The sensing line driver 144 is connected to one side and/or the other side of each of the first to mth sensing control lines SSL1 to SSLm. The sensing line driver 144 generates a second scan signal that is sequentially shifted based on the second row control signal RCS2, and generates the second high voltage VGH2 and the second low voltage VGL2. The second scan signal is level shifted with the second scan pulse SP2 to sequentially supply to the first to mth scan control lines SL1 to SLm. For example, the sensing line driver 144 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 second high. Levels of the second scan signal supplied sequentially from the second shift register unit using the voltage VGH2 and the second low voltage VGL2 are shifted to the second scan pulse SP2 to perform the first to mth operations. It may include a second level shifting unit (not shown) to supply to the sensing control line (SSL1 to SSLm).

The column driver 150 is connected to the first to nth data lines DL1 to DLn and operates in a display mode and a sensing mode according to mode control of the timing controller 120.

In the display mode, the column driver 150 generates a data voltage Vdata in units of horizontal lines based on the pixel data DATA and the data control signal DCS supplied from the timing controller 120. While supplying to the corresponding data lines DL1 to DLn, the reference voltage Vref is supplied to the corresponding reference lines RL1 to RLn. In the sensing mode, the column driver 150 switches first for each pixel P in response to sensing data DATA and a data control signal DCS for each pixel supplied from the timing controller 120. The sensing voltage Sdata is generated by sensing a threshold voltage of one of the transistor Tsw1, the second switching transistor Tsw2, and the driving transistor Tdr, and the generated sensing data Sdata is transmitted to the timing controller 120. to provide. To this end, the column (column) driving unit 150, as shown in Figure 5, is configured to include a data driving unit 152, a switching unit 154, and a sensing unit 156.

The data driver 152 receives the pixel data DATA supplied from the timing controller 120 in response to the data control signal DCS supplied from the timing controller 120 according to the display mode or the sensing mode. It is converted to the data voltage Vdata and supplied to the first to nth data lines DL1 to DLn, respectively.

The switching unit 154 responds to the data control signal DCS supplied from the timing control unit 120 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 154 may generate a pre-charging voltage Vpre supplied from the outside in response to the pre-charging switch signal supplied from the timing controller 120 according to the sensing mode. To RLn) to initialize each of the first to n-th reference lines RL1 to RLn to a pre-charging voltage Vpre, respectively, in response to the sampling switch signal, respectively to the first to n-th reference lines RL1 to RLn Is connected to the sensing unit 156. To this end, the switching unit 154 according to an example includes first to nth reference lines RL1 to RLn and first to nth selectors 154a to 154n connected to the sensing units 156, respectively. The selectors 154a to 154n may be made of a multiplexer.

The sensing unit 156 is connected to the first to n-th reference lines RL1 to RLn through the switching unit 154 in the sensing mode, so that the voltages of the first to n-th reference lines RL1 to RLn are respectively applied. It senses and generates sensing data Sdata corresponding to the sensed voltage and provides it to the timing controller 120. To this end, the sensing unit 156 includes first to nth analog-to-digital converters 156a to 156n connected to the first to nth reference lines RL1 to RLn through the switching unit 154. Can be configured.

The organic light emitting display device according to the first example of the present invention senses the threshold voltage of the driving transistor Tdr for each pixel P to generate sensing data Sdata, and senses data for each pixel P data Based on ), the voltage level of the scan pulses SP1 and SP2 supplied to each pixel P is varied to at least one threshold of the first switching transistor Tsw1 and the second switching transistor Tsw2 for each pixel P. Voltage can be compensated.

In addition, the organic light emitting diode display according to the first example of the present invention has a high voltage VGH1 of the first and second scan pulses SP1 and SP2 based on the first and second scan pulse level data SPLD1 and SPLD2. , VGH2) and the low voltages VGL1 and VGL2, respectively, to sense the threshold voltage of the first switching transistor Tsw1 or the second switching transistor Tsw2 for each pixel P.

The organic light emitting diode display according to the first example of the present invention senses the threshold voltage of the first switching transistor Tsw1 or the second switching transistor Tsw2 for each pixel P to generate sensing data Sdata. The threshold voltage of the first switching transistor Tsw1 and/or the second switching transistor Tsw2 may be compensated based on the sensing data Sdata for each pixel P.

Hereinafter, an organic light emitting display device according to a first example of the present invention will be described with reference to FIGS. 6 and 7.

6 is a diagram schematically showing an organic light emitting display device according to a first example of the present invention, and FIG. 7 is a driving waveform diagram in a sensing mode in the organic light emitting display device according to a first example of the present invention.

The sensing mode of the organic light emitting display device according to the first example of the present invention will be described with reference to FIGS. 6 and 7 as follows.

First, in the sensing mode, the organic light emitting diode display according to the first example of the present invention operates the driving transistor Tdr included in the pixel P in a source follower mode to threshold the driving transistor Tdr. The voltage is sensed. To this end, the above-described timing control unit 120 is a data control signal (DCS) for driving the pixel (P) in the first to third periods (t1, t2, t3), the first and second row control signal (RCS1) , RCS2) is generated and supplied to the above-described row driver 140 and column driver 150, and at the same time, the sensing pixel data DATA which is a bias voltage supplied to the gate electrode of the driving transistor Tdr. To generate and supply it to the column driver 150.

The row driver 140 converts each of the first and second switching transistors Tsw1 and Tsw2 into a linear driving mode during the sensing mode in response to the first and second row control signals RCS1 and RCS2. To operate, the same voltage levels are generated to supply the first and second scan pulses SP1 and SP2 to the scan control line SL and the sensing control line SSL, respectively. That is, the row driver 140 first scans having the first high voltage VGH1 during the first to third periods t1, t2, and t3 in response to the first row control signal RCS1. The first high voltage VGH1 is generated during the first and second periods t1 and t2 in response to the second low control signal RCS2 while generating the pulse SP1 and supplying it to the scan control line SL. The second scan pulse SP2 having the second high voltage VGH2 having the same voltage level and the second low voltage VGL2 during the third period t3 is generated and supplied to the sensing control line SSL.

The data driver 152 of the column driver 150 converts the pixel data DATA into a sensing bias voltage Vdata in response to the data control signal DCS, such that the first to third periods ( Data lines DL are supplied during t1, t2, and t3). At the same time, the switching unit 154 of the column driving unit 150 supplies the pre-charging voltage Vpre to the reference line RL during the first period t1 in response to the pre-charging switch signal. , Floating the reference line RL during the second period t2, and then sensing the reference line RL during the third period t3 in response to the sampling switch signal 156. Connect to. Accordingly, the sensing unit 156 senses the voltage of the reference line RL during the third period t3, and converts the sensed voltage to analog-digital conversion to generate sensing data Sdata to generate the timing control unit. (120).

In this sensing mode, the operation of each pixel P of the first to third periods t1, t2, and t3 according to the driving of each of the row driver 140 and the column driver 150 is performed. The explanation is as follows.

First, in the first period t1, the first switching transistor Tsw1 is turned on by the first scan pulse SP1 of the first high voltage VGH1 to supply the data voltage to the data line DL. (Vdata) is supplied to the gate electrode of the first node n1, that is, the driving transistor Tdr, and the second switching transistor Tsw2 is turned by the second scan pulse SP2 of the second high voltage VGH2. The pre-charge voltage Vpre that is turned on and 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 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 electrode of the driving transistor Tdr and the reference line RL are initialized to a pre-charging voltage Vpre.

Then, in the second period t2, the turn-on state of the first switching transistor Tsw1 is maintained by the first scan pulse SP1 of the first high voltage VGH1, so that the driving transistor Tdr is The gate voltage is fixed to the data voltage Vdata. At this time, the reference line RL is floated by the switching unit 154 of the column driver 150. Accordingly, the driving transistor Tdr operates in a saturation driving mode by a data voltage Vdata, which is a bias voltage supplied to the gate electrode, thereby causing the data voltage ( The difference voltage Vdata-Vth between Vdata) and the threshold voltage Vth of the driving transistor Tdr is charged.

Then, in the third period T3, while the first switching transistor Tsw1 is maintained in the turn-on state by the first scan pulse SP1 of the first high voltage VGH1, the second low The second switching transistor Tsw2 is turned off by the second scan pulse SP2 of the voltage VGL2, and at the same time, the reference line RL is the switching unit 154 of the column driver 150 ) Is connected to the sensing unit 156. Accordingly, the sensing unit 156 senses the voltage Vsense(RL) of the reference line RL, and converts the sensed voltage Vsense(RL) to analog-digital conversion to generate sensing data Sdata. Solution timing controller 120. Accordingly, the timing control unit 120 calculates and calculates a threshold voltage Vth of the driving transistor Tdr based on the data voltage Vdata and the sensing data Sdata provided from the sensing unit 156. Threshold voltage data corresponding to the threshold voltage Vth of the driven driving transistor Tdr is stored in the memory 122. In this case, the threshold voltage Vth of the driving transistor Tdr may be a voltage obtained by subtracting the sensing voltage Vsense(RL) of the sensing unit 156 from the data voltage Vdata.

8 is a driving waveform diagram in a display mode in an organic light emitting diode display according to a first example of the present invention.

The display mode of the organic light emitting diode display according to the first example of the present invention will be described with reference to FIGS. 6 and 8.

First, in the display mode, the timing controller 120 is based on the threshold voltage data of the driving transistor Tdr for each pixel P sensed by the sensing mode described above and stored in the memory 122. Voltage levels of the high voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2 of the first and second scan pulses SP1 and SP2 switching the first and second switching transistors Tsw1 and Tsw2 for each First and second scan pulse level data SPLD1 and SPLD2 for setting respectively are generated. Then, the voltage supply unit 130, as described above, based on the first and second scan pulse level data (SPLD1, SPLD2) supplied from the timing control unit 120, the first high voltage (VGH1), the first Each of the first low voltage VGL1, the second high voltage VGH2, and the second low voltage VGL2 is generated and provided to the row driver 140.

Then, in the display mode, the timing controller 120 generates first and second row control signals RCS1 and RCS2 for driving the pixel P to the addressing period DM_t1 and the light emission period DM_t2. By supplying to the above-mentioned row driver 140, the pixel data DATA and the data control signal DCS are generated and supplied to the column driver 150.

The row driver 140 has a voltage level of a first high voltage VGH1 supplied from the voltage supply unit 130 during the addressing period DM_t1 in response to the first row control signal RCS1. During the light emission period DM_t2, the first scan pulse SP1 having the voltage level of the first low voltage VGL1 supplied from the voltage supply unit 130 is generated and supplied to the scan control line SL, and at the same time 2 has a voltage level of the second high voltage VGH2 supplied from the voltage supply unit 130 during the addressing period DM_t1 in response to the low control signal RCS2, and the voltage supply unit 130 during the light emission period DM_t2 ) Generates a second scan pulse SP2 having a voltage level of the second low voltage VGL2 and supplies it to the sensing control line SSL.

The column driver 150 converts the data voltage Vdata to the addressing period DM_t1 according to the driving of the data driver 152 based on the pixel data DATA and the data control signal DCS. ) To the data line DL. At the same time, the column driver 150 is a reference voltage Vref to the reference line RL during the addressing period DM_t1 according to the driving of the above-described switching unit 154 based on the data control signal DCS. ).

In the display mode, the operation of the pixel P of each of the addressing period DM_t1 and the light emission period DM_t2 according to the driving of each of the row driving unit 140 and the column driving unit 150 will be described. As follows.

First, in the addressing period DM_t1, the first switching transistor Tsw1 is turned on by the first scan pulse SP1 of the first high voltage VGH1 to supply the data voltage DL to the data line DL. Vdata) is supplied to the first node n1, that is, the gate electrode of the driving transistor Tdr, and the second switching transistor Tsw2 is turned on by the second scan pulse SP2 of the second high voltage VGH2. The reference voltage Vref that is turned on and supplied to the reference line RL is supplied to the second 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. In the addressing period DM_t1, each of the first and second switching transistors Tsw1 and Tsw2 is a scan pulse SP1 of the high voltages VGH1 and VGH2 set based on the threshold voltage of the sensed driving transistor Tdr. , SP2), whereby each of the reference voltages Vref of the data voltages Vdata is affected by threshold voltages of the first and second switching transistors Tsw1 and Tsw2, respectively. It is supplied to the nodes (n1, n2).

Then, in the light emission period DM_t2, the first switching transistor Tsw1 is turned off by the first scan pulse SP1 of the first low voltage VGL1, and the second low voltage VGL2 is turned off. The second switching transistor Tsw2 is turned off by the second scan pulse SP2 so that the driving transistor Tdr is turned on by the voltage Vdata-Vref stored in the capacitor Cst. Accordingly, the turned-on driving transistor Tdr supplies the data current Ioled determined by the difference voltage Vdata-Vref between the data voltage Vdata and the reference voltage Vref to the light emitting device OLED. By doing so, the light emitting element 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 light emitting element OLED emits light in proportion to the current. The voltage of the second node n2 rises while starting, and the voltage of the first node n1 increases by the voltage of the capacitor Cst by the voltage rise of the second node n2 by the capacitor Cst. The gate-source voltage Vgs of the driving transistor Tdr is continuously maintained so that the light emitting device OLED continues to emit light until the addressing period DM_t1 of the next frame.

9A to 9D are diagrams for explaining a variation of a high voltage and a low voltage of a scan pulse supplied to each of the scan control line and the sensing control line in the organic light emitting display device according to the first example of the present invention.

First, as will be described later, since the change in threshold voltages of the driving transistors Tdr for each pixel P formed in the display panel 110 and the first and second switching transistors Tsw1 and Tsw2 are similar, the present invention The organic light emitting display according to the first example of the first and second scan pulses SP1 and SP2 supplied to each pixel P based on the threshold voltage data of the driving transistor Tdr sensed through the sensing mode. The threshold voltages of the first and second switching transistors Tsw1 and Tsw2 are compensated by varying the voltage levels of the high voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2, respectively. To this end, the timing controller 120 is based on threshold voltage data for each pixel P stored in the memory 122, among the maximum value, the minimum value, the average value, the average value of the upper values, and the average value of the lower values. Any one is calculated as a compensation reference value, and based on the calculated compensation reference value, first and second scan pulse level data SPLD1 and SPLD2 are respectively generated and provided to the above-described voltage supply unit 130, or in the memory 122. By comparing the reference threshold voltage data for the driving transistor Tdr for each pixel P and the threshold voltage data for each sensed pixel P, the direction of change of the threshold voltage is detected, and the direction of change of the detected threshold voltage First and second scan pulse level data SPLD1 and SPLD2 are respectively generated based on the compensation reference value, and are provided to the above-described voltage supply unit 130.

Specifically, the timing control unit 120 includes scan pulse level data corresponding to voltage levels of the high voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2 of the scan pulses SP1 and SP2 for the compensation reference value. Each of the first and second scan pulse level data SPLD1 and SPLD2 corresponding to the compensation reference value may be generated using the mapped look-up table.

As an example, each of the first and second scan pulse level data SPLD1 and SPLD2 has a voltage level of each of a high voltage and a low voltage of the scan pulses SP1 and SP2, as shown in FIG. 9A. It may be set to be upward according to the compensation reference value Ref_Vth.

As another example, each of the first and second scan pulse level data SPLD1 and SPLD2 has a reference voltage of the low voltages VGL1 and VGL2 of the scan pulses SP1 and SP2, respectively, as illustrated in FIG. 9B. It is set to be fixed at a level, and the voltage levels of each of the high voltages VGH1 and VGH2 of the scan pulses SP1 and SP2 may be set to be increased according to the compensation reference value Ref_Vth.

As another example, each of the first and second scan pulse level data SPLD1 and SPLD2 has a reference voltage of high voltages VGH1 and VGH2 of scan pulses SP1 and SP2, as shown in FIG. 9C. It is fixed to a level, and the voltage levels of each of the low voltages VGL1 and VGL2 of the scan pulses SP1 and SP2 may be set to be increased according to the compensation reference value Ref_Vth.

As another example, when the characteristic change direction of the driving transistor Tdr is a positive shift, as illustrated in FIG. 9D, each of the first and second scan pulse level data SPLD1 and SPLD2 is The voltage levels of the high voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2 of the scan pulses SP1 and SP2 may be set to be downward according to the compensation reference value Ref_Vth. Here, each of the first and second scan pulse level data SPLD1 and SPLD2 has the high voltages VGH1 and VGH2 of the scan pulses SP1 and SP2 fixed to a reference high voltage level regardless of the compensation reference value Ref_Vth. It can be set as possible.

When the characteristic change direction of the driving transistor Tdr is a negative shift, as shown in FIG. 9D, each of the first and second scan pulse level data SPLD1 and SPLD2 is the scan pulse SP1. , The voltage levels of the high voltages VGH1 and VGH2 of SP2 and the low voltages VGL1 and VGL2 may be set to be increased according to the compensation reference value Ref_Vth. Here, each of the first and second scan pulse level data SPLD1 and SPLD2 has the low voltages VGL1 and VGL2 of the scan pulses SP1 and SP2 fixed to a reference low voltage level regardless of the compensation reference value Ref_Vth. It can be set as possible.

10 is a diagram schematically showing an organic light emitting display device according to a second example of the present invention, and FIG. 11 is a driving waveform diagram in a sensing mode in the organic light emitting display device according to a second example of the present invention.

The sensing mode of the organic light emitting diode display according to the second example of the present invention will be described with reference to FIGS. 10 and 11 as follows.

First, in the sensing mode, the organic light emitting diode display according to the second example of the present invention operates the first switching transistor Tsw1 included in the pixel P in a source follower mode to operate the first switching transistor ( The threshold voltage of Tsw1) is sensed. To this end, the above-described timing control unit 120 is a data control signal (DCS) for driving the pixel (P) in the first to third periods (t1, t2, t3), the first and second row control signal (RCS1) , RCS2) is generated and supplied to the above-mentioned row driver 140 and column driver 150, and at the same time, the sensing pixel data for operating the driving transistor Tdr in a saturation driving mode ( DATA) (for example, the maximum grayscale value) is generated and supplied to the column driver 150. In addition, the timing controller 120 linearly converts the first scan pulse level data SPLD1 and the second switching transistor Tsw2 for applying a bias voltage to the gate electrode of the first switching transistor Tsw1. Each of the second scan pulse level data SPLD2 for operating in the driving mode is generated and supplied to the voltage supply unit 130.

The voltage supply unit 130 generates the first high voltage VGH1 and the first low voltage VGL1 based on the first scan pulse level data SPLD1 and supplies them to the row driver 140 at the same time. A second high voltage VGH2 higher than the first high voltage VGH1 and a second low voltage VGL2 lower than the first low voltage VGL1 are generated based on the second scan pulse level data SPLD2. It supplies to the row driving unit 140. For example, the first high voltage VGH1 is 3 to 6V, the first low voltage VGL1 is -6V, the second high voltage VGH2 is 23V, and the second low voltage VGL2 is- It can be 7V.

The row driver 140 has a first high voltage VGH1 during the first to third periods t1, t2, and t3 of the sensing mode described above in response to the first row control signal RCS1. While generating the first scan pulse SP1 and supplying it to the scan control line SL, in response to the second low control signal RCS2, the second high voltage during the first and second periods t1 and t2 ( VGH1), and generates a second scan pulse SP2 having a second low voltage VGL2 during the third period t3 and supplies it to the sensing control line SSL.

The column driver 150 converts the data voltage Vdata according to the driving of the data driver 152 based on the pixel data DATA and the data control signal DCS to the first to third. The data lines DL are supplied during the periods t1, t2, and t3. At the same time, the column driver 150 precharges the reference line RL during the first period t1 according to the driving of the switching unit 154 based on the data control signal DCS. After supplying (Vpre), the reference line RL is floated for the second period t2, and then the reference line RL is sensed for the third period t3. 156). Accordingly, the sensing unit 156 senses the voltage of the reference line RL during the third period t3, and converts the sensed voltage to analog-digital conversion to generate sensing data Sdata to generate the timing control unit. (120).

In this sensing mode, the operation of each pixel P of the first to third periods t1, t2, and t3 according to the driving of each of the row driver 140 and the column driver 150 is performed. The explanation is as follows.

First, in the first period t1, the first switching transistor Tsw1 is turned on by the first scan pulse SP1 of the first high voltage VGH1 to supply the data voltage to the data line DL. (Vdata) is supplied to the gate electrode of the first node n1, that is, the driving transistor Tdr, and the second switching transistor Tsw2 is turned by the second scan pulse SP2 of the second high voltage VGH2. The pre-charge voltage Vpre that is turned on and supplied to the reference line RL is supplied to the second node n2, that is, the source electrode of the driving transistor Tdr. Accordingly, during the first period t1, the source electrode of the driving transistor Tdr and the reference line RL are initialized to a pre-charging voltage Vpre.

Then, in the second period t2, since the turn-on state of the first switching transistor Tsw1 is maintained by the first scan pulse SP1 of the first high voltage VGH1, the driving transistor Tdr is In the state where the turn-on state is maintained by the data voltage Vdata, the gate voltage of the first switching transistor Tsw1 is fixed to the first high voltage VGH1 that is the bias voltage. At the same time, the reference line RL is floated by the switching unit 154 of the column driving unit 150. Accordingly, the first switching transistor Tsw1 operates in a saturation driving mode by the first high voltage VGH1, which is a bias voltage supplied to the gate electrode, and thereby the reference line RL in the floating state. ) Is charged by subtracting the voltages VGH1-Vth_Tsw1-Vth_Tdr of the first high voltage VGH1 from the threshold voltage Vth_Tsw1 of the first switching transistor Tsw1 and the threshold voltage Vth_Tdr of the driving transistor Tdr. .

Then, in the third period T3, while the first switching transistor Tsw1 is maintained in the turn-on state by the first scan pulse SP1 of the first high voltage VGH1, the second low The second switching transistor Tsw2 is turned off by the second scan pulse SP2 of the voltage VGL2, and at the same time, the reference line RL is the switching unit 154 of the column driver 150 ) Is connected to the sensing unit 156. Accordingly, the sensing unit 156 senses the voltage Vsense(RL) of the reference line RL, and converts the sensed voltage Vsense(RL) to analog-digital conversion to generate sensing data Sdata. Solution timing controller 120. Accordingly, the timing control unit 120 may include a threshold voltage Vth, the first high voltage VGH1, and the sensing unit 156 of the driving transistor Tdr of the corresponding pixel P stored in the memory 122. The threshold voltage Vth of the first switching transistor Tsw1 is calculated based on the sensing data Sdata provided from the threshold voltage data corresponding to the calculated threshold voltage Vth of the first switching transistor Tsw1. Is stored in the memory 122. As a result, the threshold voltage Vth of the first switching transistor Tsw1 is the threshold voltage Vth_Tdr of the driving transistor Tdr and the sensing voltage of the sensing unit 156 at the first high voltage VGH1. It can be the voltage minus Vsense(RL)).

In the display mode of the organic light emitting diode display according to the second example of the present invention, the above-described compensation reference value is calculated based on the threshold voltage Vth of the first switching transistor Tsw1 for each sensed pixel P And changing the first high voltage VGH1 and the first low voltage VGL1 of the first scan pulse SP1 based on the compensation reference value calculated as shown in any one of FIGS. 9A to 9D. 6 and 8 are the same as the display mode of the organic light emitting display device according to the first example of the present invention described above, so a duplicate description thereof will be omitted. Furthermore, each of the second high voltage VGH2 and the second low voltage VGL2 of the second scan pulse SP2 in the display mode of the organic light emitting diode display according to the second example of the present invention is variable according to the compensation reference value. It might be.

12 is a diagram schematically showing an organic light emitting display device according to a third example of the present invention, and FIG. 13 is a driving waveform diagram in a sensing mode in the organic light emitting display device according to a third example of the present invention.

A sensing mode of the organic light emitting diode display according to the third example of the present invention will be described with reference to FIGS. 12 and 13 as follows.

First, in the sensing mode, the organic light emitting display device according to the third example of the present invention operates the second switching transistor Tsw2 included in the pixel P in a source follower mode to operate the second switching transistor ( The threshold voltage of Tsw2) is sensed. To this end, the above-described timing control unit 120 is a data control signal (DCS) for driving the pixel (P) in the first to third periods (t1, t2, t3), the first and second row control signal (RCS1) , RCS2) and supplying the above-described row driver 140 and column driver 150 while simultaneously sensing pixel data for sensing to operate the driving transistor Tdr in a linear driving mode ( DATA) (for example, the maximum grayscale value) is generated and supplied to the column driver 150. In addition, the timing control unit 120 may be applied to the first scan pulse level data SPLD1 and the gate electrode of the second switching transistor Tsw2 for operating the first switching transistor Tsw1 in a linear driving mode. Each of the second scan pulse level data SPLD2 for applying a bias voltage is generated and supplied to the voltage supply unit 130.

The voltage supply unit 130 generates the first high voltage VGH1 and the first low voltage VGL1 based on the first scan pulse level data SPLD1 and supplies them to the row driver 140 at the same time. A second high voltage VGH2 lower than the first high voltage VGH1 and a second low voltage VGL2 higher than the first low voltage VGL1 are generated based on the second scan pulse level data SPLD2. It supplies to the row driving unit 140. For example, the first high voltage VGH1 is 23V, the first low voltage VGL1 is -7V, the second high voltage VGH2 is 3-6V, and the second low voltage VGL2 is- It can be 6V.

The row driver 140 has a first high voltage VGH1 during the first to third periods t1, t2, and t3 of the sensing mode described above in response to the first row control signal RCS1. While generating the first scan pulse SP1 and supplying it to the scan control line SL, in response to the second low control signal RCS2, the second high voltage during the first and second periods t1 and t2 ( VGH1), and generates a second scan pulse SP2 having a second low voltage VGL2 during the third period t3 and supplies it to the sensing control line SSL.

The column driver 150 converts the data voltage Vdata according to the driving of the data driver 152 based on the pixel data DATA and the data control signal DCS to the first to third. The data lines DL are supplied during the periods t1, t2, and t3. At the same time, the column driver 150 precharges the reference line RL during the first period t1 according to the driving of the switching unit 154 based on the data control signal DCS. After supplying (Vpre), the reference line RL is floated for the second period t2, and then the reference line RL is sensed for the third period t3. 156). Accordingly, the sensing unit 156 senses the voltage of the reference line RL during the third period t3, and converts the sensed voltage to analog-digital conversion to generate sensing data Sdata to generate the timing control unit. (120).

In this sensing mode, the operation of each pixel P of the first to third periods t1, t2, and t3 according to the driving of each of the row driver 140 and the column driver 150 is performed. The explanation is as follows.

First, in the first period t1, the first switching transistor Tsw1 is turned on by the first scan pulse SP1 of the first high voltage VGH1 to supply the data voltage to the data line DL. (Vdata) is supplied to the gate electrode of the first node n1, that is, the driving transistor Tdr, and the second switching transistor Tsw2 is turned by the second scan pulse SP2 of the second high voltage VGH2. The pre-charge voltage Vpre that is turned on and supplied to the reference line RL is supplied to the second node n2, that is, the source electrode of the driving transistor Tdr. Accordingly, during the first period t1, the source electrode of the driving transistor Tdr is initialized to the pre-charging voltage Vpre.

Then, in the second period t2, since the turn-on state of the first switching transistor Tsw1 is maintained by the first scan pulse SP1 of the first high voltage VGH1, the driving transistor Tdr is The driving power EVdd that is turned on by the data voltage Vdata and supplied to the driving power line PL is supplied to the second node n2, that is, the drain electrode of the second switching transistor Tsw2. Further, the gate voltage of the second switching transistor Tsw2 is fixed to the second high voltage VGH2 which is a bias voltage. At the same time, the reference line RL is floated by the switching unit 154 of the column driving unit 150. Accordingly, the second switching transistor Tsw2 operates in a saturation driving mode by the second high voltage VGH2, which is a bias voltage supplied to the gate electrode, thereby causing the reference line RL in the floating state. ) Is charged with the difference voltage VGH2-Vth of the second high voltage VGH2 and the threshold voltage Vth of the second switching transistor Tsw2.

Then, in the third period T3, while the first switching transistor Tsw1 is maintained in the turn-on state by the first scan pulse SP1 of the first high voltage VGH1, the second low The second switching transistor Tsw2 is turned off by the second scan pulse SP2 of the voltage VGL2, and at the same time, the reference line RL is the switching unit 154 of the column driver 150 ) Is connected to the sensing unit 156. Accordingly, the sensing unit 156 senses the voltage Vsense(RL) of the reference line RL, and converts the sensed voltage Vsense(RL) to analog-digital conversion to generate sensing data Sdata. Solution timing controller 120. Accordingly, the timing control unit 120 sets the threshold voltage Vth of the second switching transistor Tsw2 based on the second high voltage VGH2 and the sensing data Sdata provided from the sensing unit 156. The threshold voltage data corresponding to the calculated threshold voltage Vth of the second switching transistor Tsw2 is stored in the memory 122. As a result, the threshold voltage Vth of the second switching transistor Tsw2 may be a voltage obtained by subtracting the sensing voltage Vsense(RL) of the sensing unit 156 from the second high voltage VGH2.

In the display mode of the OLED display according to the third example of the present invention, the above-described compensation reference value is calculated based on the threshold voltage Vth of the second switching transistor Tsw2 for each sensed pixel P And changing the second high voltage VGH2 and the second low voltage VGL2 of the second scan pulse SP2 based on the compensation reference value calculated as shown in any one of FIGS. 9A to 9D. 6 and 8 are the same as the display mode of the organic light emitting display device according to the first example of the present invention described above, so a duplicate description thereof will be omitted. Furthermore, each of the first high voltage VGH1 and the first low voltage VGL1 of the first scan pulse SP1 in the display mode of the organic light emitting diode display according to the third example of the present invention is variable according to the compensation reference value. It might be.

Meanwhile, in the organic light emitting display device according to the third example of the present invention, the first switching transistor Tsw1 is switched by the first scan pulse SP1 supplied to the scan control line SL, and the second switching Although the transistor Tsw2 is described as being switched by the second scan pulse SP2 supplied to the sensing control line SSL, the present invention is not limited thereto, and in the modified example of the organic light emitting display device according to the third example of the present invention Either one of the scan control line SL and the sensing control line SSL may be omitted, and in the following description, it is assumed that the sensing control line SSL is omitted or is electrically connected to the scan control line SL. .

In the modified example, the first and second switching transistors Tsw1 and Tsw2 may be simultaneously switched by the scan pulse SP supplied to the scan control line SL, as shown in FIG. 14. Here, in the sensing mode, the scan pulse SP may be formed of the same high voltage VGH2 and low voltage VGL2 as the second scan pulse SP2. Also, in the display mode, each of the high voltage and the low voltage of the scan pulse SP may be varied according to the compensation reference value.

In the modified example of the organic light emitting display device according to the third example of the present invention, in the sensing mode or the display mode, the first and second switching transistors Tsw1 and Tsw2 are simultaneously driven by the one scan pulse SP. Except for being switched, since it is the same as the sensing mode or the display mode described above with reference to FIGS. 12 and 13, redundant description thereof will be omitted.

In this modification of the organic light emitting display device according to the third example of the present invention, the sensing line driver 144 of the row driver 140 described above can be omitted, thereby reducing circuit cost, The plurality of sensing control lines SSL1 to SSLm formed on the display panel 110 may be omitted, thereby increasing the aperture ratio of each pixel P.

On the other hand, although not shown, the organic light emitting display device according to the fourth example of the present invention corresponds to the threshold voltage of the driving transistor Tdr for each pixel P through the sensing mode of the first organic light emitting display device ( After storing the first threshold voltage data for each P) in the memory 122, the pixels corresponding to the threshold voltage of the second switching transistor Tsw2 for each pixel P through the sensing mode of the third organic light emitting display device described above. The second threshold voltage data for each (P) is stored in the memory 122. Then, in the organic light emitting display device according to the fourth example of the present invention, in the display mode, the first characteristic compensation value for each pixel P is calculated based on the first threshold voltage data for each pixel P stored in the memory 122. At the same time, the second characteristic compensation value for each pixel P is calculated based on the second threshold voltage data for each pixel P stored in the memory 122, and then the first and second characteristics for each pixel P are calculated. Compensation data DATA is generated and displayed on each pixel P by reflecting the compensation value to the image data Idata of the corresponding pixel P. Accordingly, the organic light emitting diode display according to the fourth example of the present invention is not only the luminance deviation according to the threshold voltage deviation of the driving transistor Tdr for each pixel, but also the luminance deviation according to the threshold voltage deviation of the second switching transistor Tsw2 for each pixel. Can compensate at the same time.

15 is a block diagram illustrating an example of a timing controller for generating scan pulse level data in the organic light emitting diode display according to the second or third example of the present invention.

First, each of the first and second switching transistors Tsw1 and Tsw2 for each pixel P has a threshold voltage (Vth)/mobility characteristic changed in a forward or reverse direction due to a voltage stress due to driving. Can be. The change in characteristics of the first and second switching transistors Tsw1 and Tsw2 may be derived through a relational expression according to the driving time or may be derived through a look-up table to which a characteristic change amount according to the driving time is mapped. Accordingly, the timing control unit 120, in the display mode, the driving time based on the sensing data Sdata of the first and/or second switching transistors Tsw1 and Tsw2 sensed by the sensing mode described above. High of the first and second scan pulses SP1 and SP2 using a relational expression for calculating the threshold voltage change of the switching transistors Tsw1 and Tsw2 or a lookup table in which the threshold voltage change amount for the driving time is mapped. First and second scan pulse level data SPLD1 and SPLD2 for varying voltage levels of the voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2 are generated.

Referring to FIG. 15, in the organic light emitting display device according to the second or third example of the present invention, the timing control unit 120 according to an example is driven time of the first and/or second switching transistors Tsw1 and Tsw2 It may be configured to include a scan pulse level data generation unit 125 for generating the first and second scan pulse level data (SPLD1, SPLD2) by using a relational expression for calculating the threshold voltage change for.

The scan pulse level data generation unit 125 may include a driving time calculation unit 125a and a scan pulse level setting unit 125b.

The driving time calculation unit 125a calculates a driving time DT of the first and/or second switching transistors Tsw1 and Tsw2 by counting a timing synchronization signal TSS, that is, a vertical synchronization signal or a horizontal synchronization signal. .

The scan pulse level setting unit 125b through calculation of a relational expression in which the driving time DT of the first and/or second switching transistors Tsw1 and Tsw2 supplied from the driving time calculator 125a is a variable The first and/or second switching transistors Tsw1 and Tsw2 calculate threshold voltage changes, and the calculated first and/or second switching transistors Tsw1 and Tsw2 based on the threshold voltage variation. Scan pulse level data SPLD1 and SPLD2 are generated. Here, the relational expression may be individually set for each of the first and second switching transistors Tsw1 and Tsw2. This relational expression analyzes threshold voltage data for each driving time of each of the first and/or second switching transistors Tsw1 and Tsw2 collected by the above-described sensing mode performed in the inspection process before shipment of the product of the organic light emitting diode display. Can be derived through

The organic light emitting display device according to the second or third example of the present invention has the voltage of the scan pulses SP1 and SP2 according to the driving time DT of the first and/or second switching transistors Tsw1 and Tsw2. By changing the level, the voltage stress of the first and/or second switching transistors Tsw1, Tsw2 during initial driving of the first and/or second switching transistors Tsw1, Tsw2 is reduced, and the first and And/or the threshold voltage change of the second switching transistors Tsw1 and Tsw2 may be compensated.

16 is a block diagram illustrating another example of a timing control unit for generating scan pulse level data in the organic light emitting diode display according to the second or third example of the present invention.

Referring to FIG. 16, in the organic light emitting diode display device according to the second or third example of the present invention, the timing control unit 120 according to another example is a driving time of the first and/or second switching transistors Tsw1 and Tsw2 And a scan pulse level data generation unit 125 generating first and second scan pulse level data SPLD1 and SPLD2 using a look-up table to which a threshold voltage variation (TVV) corresponding to is mapped. Can be.

The scan pulse level data generation unit 125 may include a driving time calculation unit 125a, a scan pulse level setting unit 125b, and a look-up table (LUT).

The driving time calculation unit 125a calculates a driving time DT of the first and/or second switching transistors Tsw1 and Tsw2 by counting a timing synchronization signal TSS, that is, a vertical synchronization signal or a horizontal synchronization signal. .

The look-up table (LUT) analyzes a change amount and a change direction of threshold voltage data of the first and/or second switching transistors Tsw1 and Tsw2 for each pixel sensed by the sensing mode through a preliminary experiment in units of driving time. The threshold voltage change amount TVV corresponding to the driving time of the first and/or second switching transistors Tsw1 and Tsw2 derived by is mapped.

The scan pulse level setting unit 125b corresponds to the driving time DT of the first and/or second switching transistors Tsw1 and Tsw2 supplied from the driving time calculator 125a in the look-up table LUT. The corresponding threshold voltage change amount TVV is extracted, and the first and second scan pulse level data SPLD1, based on the threshold voltage change amount TVV of the extracted first and/or second switching transistors Tsw1 and Tsw2, SPLD2). Here, the look-up table LUT may be provided separately for each of the first and second switching transistors Tsw1 and Tsw2. The look-up table (LUT) is a threshold for each driving time of each of the first and/or second switching transistors Tsw1 and Tsw2 collected by the above-described sensing mode performed in an inspection process before product shipment of the organic light emitting display device. It can be derived through analysis of voltage data.

The organic light emitting display device according to the second or third example of the present invention reduces voltage stress of the first and/or second switching transistors Tsw1 and Tsw2 during initial driving, and the first and And/or the threshold voltage change of the second switching transistors Tsw1 and Tsw2 may be compensated.

17 is a block diagram illustrating a timing control unit of an organic light emitting diode display according to a fourth example of the present invention.

Referring to FIG. 17, the timing controller 120 of the organic light emitting diode display according to the fourth example of the present invention operates the above-described column driver 150 and row driver 140 in a sensing mode. , The sensing data Sdata provided from the column driver 150 by the sensing mode is stored in the memory 122.

In the display mode, the timing controller 120 includes first threshold voltage data Vth_Tdr of the driving transistor Tdr for each pixel P stored in the memory 122 and a second threshold voltage of the second switching transistor Tsw2. Based on the data Vth_Tsw2, image data Idata for each pixel P is corrected to generate pixel data DATA for each pixel and supplied to the column driver 150 described above. To this end, the timing control unit 120 includes a data processing unit 127.

The data processing unit 127 according to an example may include a data alignment unit 127a, a look-up table 127b, and a data correction unit 127c.

The data alignment unit 127a arranges image data Idata input from an external driving system (or graphics card) to match the driving of the display panel 110 to generate pixel-specific input data Idata'. .

The look-up table 127b stores the second characteristic compensation value θ set for each correction data for each threshold voltage data Vth_Tsw2 of the second switching transistor Tsw2. Here, the second characteristic compensation value θ is set through a pre-simulation process that compensates for a variation in data voltage with respect to a change in the threshold voltage data Vth_Tsw2 of the second switching transistor Tsw2, and the threshold voltage data ( Vth_Tsw2) is set for each correction data.

The data correction unit 127c is sensed by the first threshold voltage data Vth_Tdr of the driving transistor Tdr for each pixel P stored in the memory 122 and sensed by the previous sensing mode, and sensed by the first sensing mode. Based on the deviation between the initial threshold voltage data of the driving transistor Tdr for each pixel P stored in the memory 122, a pixel-by-pixel compensation for compensating for a change in the threshold voltage of the driving transistor Tdr for each pixel P After calculating the one characteristic compensation value, the input data Idata' of the corresponding pixel P is first-corrected using the calculated first characteristic compensation value for each pixel P to generate pixel-specific correction data. Then, the data correction unit 127c is the second threshold voltage data Vth_Tsw2 of the second switching transistor Tsw2 for each pixel P sensed by the previous sensing mode and stored in the memory 122, and corresponding correction data. The second characteristic compensation value (θ) for each pixel (P) corresponding to is extracted from the look-up table (127b), and the second characteristic compensation value (θ) for each pixel (P) is used for the corresponding pixel (P). The correction data is secondly corrected to generate pixel data DATA for each pixel, and then the generated pixel data DATA for each pixel is supplied to the column driver 150 described above.

The data processing unit 127 according to another example may include a data alignment unit 127a, a look-up table 127b, and a data correction unit 127c.

The data alignment unit 127a arranges image data Idata input from an external driving system (or graphics card) to match the driving of the display panel 110 to generate pixel-specific input data Idata'. .

The look-up table 127b includes coefficients (a, b, c) of a quadratic equation (y=ax ² +bx+c) set for each correction data for each threshold voltage data Vth_Tsw2 of the second switching transistor Tsw2, That is, the coefficient (a) of the secondary variable, the coefficient (b) of the primary variable, and the coefficient (or constant) (b) of the 0th variable are stored. Here, the coefficients (a, b, c) of the quadratic equation are set through a pre-simulation process for compensating the deviation of the data voltage with respect to the change in the threshold voltage data (Vth_Tsw2) of the second switching transistor Tsw2, The threshold voltage data Vth_Tsw2 is set for each correction data.

The data correction unit 127c is sensed by the first threshold voltage data Vth_Tdr of the driving transistor Tdr for each pixel P stored in the memory 122 and sensed by the previous sensing mode, and sensed by the first sensing mode. Based on the deviation between the initial threshold voltage data of the driving transistor Tdr for each pixel P stored in the memory 122, a pixel-by-pixel compensation for compensating for a change in the threshold voltage of the driving transistor Tdr for each pixel P After calculating the one characteristic compensation value, the input data Idata' of the corresponding pixel P is firstly corrected using the calculated first characteristic compensation value for each pixel P to generate pixel-specific correction data. Then, the data correction unit 127c is the second threshold voltage data Vth_Tsw2 of the second switching transistor Tsw2 for each pixel P sensed by the previous sensing mode and stored in the memory 122 and corresponding correction data. The coefficients (a, b, c) of the quadratic equation for each pixel (P) corresponding to are extracted from a look-up table (127b), and the coefficients (a, b,) of the quadratic equation for each pixel (P) extracted c) and generating pixel data DATA for each pixel through calculation of a quadratic equation using the correction data of the corresponding pixel P, and then generating the generated pixel data DATA for each pixel by using the above-described column driver ( 150).

18 is a flowchart illustrating a method of driving an organic light emitting display device according to a first example of the present invention, which relates to a method of driving an organic light emitting display device according to examples 1 to 3 of the present invention described above.

The driving method of the organic light emitting diode display according to the first example of the present invention will be described with reference to FIG. 18 in connection with FIG. 6.

First, each pixel P of the display panel 110 is driven in the first to third periods t1, t2, and t3 under the control of the above-described timing control unit 120 according to the sensing mode, so that each pixel P is The driving transistor Tdr is operated in a source follower mode to sense a threshold voltage of the driving transistor Tdr for each pixel P through the reference line RL to generate sensing data Sdata. (Sdata) is stored in the memory 122 (S210).

Then, the above-described compensation reference value for the display panel 110 is calculated based on the threshold voltage data of the driving transistor Tdr for each pixel P sensed by the sensing mode and stored in the memory 122 (S220). ).

Then, a look-up table in which scan pulse level data corresponding to voltage levels of the high voltages VGH1 and VGH2 and the low voltages VGL1 and VGL2 of the scan pulses SP1 and SP2 for the compensation reference values are mapped is mapped. Each of the first and second scan pulse level data SPLD1 and SPLD2 corresponding to the compensation reference value is generated using (S230).

Then, based on the first and second scan pulse level data SPLD1 and SPLD2, respectively, the first high voltage VGH1 of the first scan pulse SP1 as shown in any one of FIGS. 9A to 9D. ) And the first low voltage VGL1 and the second high voltage VGH2 and the second low voltage VGL2 of the second scan pulse SP2 (S240 ).

Then, as shown in FIG. 8, while supplying the first scan pulse SP1 of the first high voltage VGH1 to the scan control line SL, the second scan of the second high voltage VGH2 The pulse SP2 is supplied to the sensing control line SSL, and the data voltage Vdata corresponding to the image data is supplied to the data line DL of the display panel 110 so as to synchronize with the image to each pixel P. Is displayed (S250).

Meanwhile, when FIG. 18 is combined with FIG. 10, in the driving method of the organic light emitting diode display according to the second example of the present invention, in step S210 described above, the first switching transistor Tsw1 for each pixel P is a source follower ( source follower) mode to sense the threshold voltage of the first switching transistor Tsw1 for each pixel P through the reference line RL to generate sensing data Sdata and store it in the memory 122, as described above. In step S220, all are the same except that the compensation reference value for the display panel 110 is calculated based on the threshold voltage data of the first switching transistor Tsw1 for each pixel P stored in the memory 122. Redundant description of this will be omitted.

Meanwhile, when FIG. 18 is combined with FIG. 12, in the driving method of the organic light emitting diode display according to the third example of the present invention, in step S210 described above, the second switching transistor Tsw2 for each pixel P is a source follower ( source follower) mode to sense the threshold voltage of the second switching transistor Tsw2 for each pixel P through the reference line RL to generate sensing data Sdata and store it in the memory 122, as described above. In step S220, all are the same except that the compensation reference value for the display panel 110 is calculated based on the threshold voltage data of the second switching transistor Tsw2 for each pixel P stored in the memory 122. Redundant description of this will be omitted.

Meanwhile, when FIG. 18 is combined with FIG. 14, the driving method of the organic light emitting diode display according to the third example of the present invention includes the first and second switching transistors Tsw1 and Tsw2 for each pixel P in step S210 described above. ) May switch one scan pulse SP at the same time.

19 is a flowchart illustrating a method of driving an organic light emitting display device according to a modification of the second or third example of the present invention, which is an organic example according to a modification of the second or third example of the present invention illustrated in FIG. 15. A method of driving a light emitting display device or a method of driving an organic light emitting display device according to another modification of the second or third example of the present invention illustrated in FIG. 16.

The driving method of the organic light emitting display device according to the modification of the second or third example of the present invention will be described with reference to FIG. 19 in connection with FIG. 15 or 16.

First, each pixel P of the display panel 110 is driven in the first to third periods t1, t2, and t3 under the control of the above-described timing control unit 120 according to the sensing mode, so that each pixel P is Threshold voltages of the first or second switching transistors Tsw1 and Tsw2 for each pixel P through the reference line RL by operating the first or second switching transistors Tsw1 and Tsw2 in a source follower mode Sensing to generate the sensing data (Sdata), and stores the sensing data (Sdata) in the memory (122) (S310).

Then, the threshold voltage of the switching transistor with respect to the driving time based on the threshold voltage data of the first or second switching transistors Tsw1 and Tsw2 for each pixel P sensed by the sensing mode and stored in the memory 122. A lookup table (LUT) in which a threshold voltage variation is mapped to a relational expression or a driving time for calculating the variation is prepared (S320).

Then, the timing synchronization signal TSS, that is, the vertical synchronization signal or the horizontal synchronization signal is counted to calculate the driving time DT of the first and/or second switching transistors Tsw1 and Tsw2 (S330).

Then, the first and/or second switching transistor Tsw1 corresponding to the driving time DT of the first and/or second switching transistors Tsw1 and Tsw2 using a relational expression or a look-up table LUT The threshold voltage change amount of Tsw2) may be calculated, and the first and second scan pulse level data SPLD1 and SPLD2 may be generated based on the calculated threshold voltage change amount (S340).

Then, based on the first and second scan pulse level data SPLD1 and SPLD2, respectively, the first high voltage VGH1 of the first scan pulse SP1 as shown in any one of FIGS. 9A to 9D. ) And the first low voltage VGL1 and the second high voltage VGH2 and the second low voltage VGL2 of the second scan pulse SP2 (S350 ).

Then, as shown in FIG. 8, while supplying the first scan pulse SP1 of the first high voltage VGH1 to the scan control line SL, the second scan of the second high voltage VGH2 The pulse SP2 is supplied to the sensing control line SSL, and the data voltage Vdata corresponding to the image data is supplied to the data line DL of the display panel 110 so as to synchronize with the image to each pixel P. Is displayed (S360).

20 is a flowchart for explaining a method of driving an organic light emitting display device according to a fourth example of the present invention, which is a driving of the organic light emitting display device according to a fourth example of the present invention including the timing controller shown in FIG. 17. It's about how.

Referring to FIG. 20 in connection with FIG. 17, a method of driving an organic light emitting display device according to a fourth example of the present invention will be described.

First, each pixel P of the display panel 110 is driven in the first to third periods t1, t2, and t3 under the control of the above-described timing control unit 120 according to the sensing mode, so that each pixel P is The driving transistor Tdr is operated in a source follower mode to sense the threshold voltage of the driving transistor Tdr for each pixel P through the reference line RL to generate sensing data Sdata (S410). The first threshold voltage data Vth_Tdr for each pixel P corresponding to the sensing data Sdata of the driving transistor Tdr for each sensed pixel P is stored in the memory 122 (S420).

Then, each pixel P of the display panel 110 is driven in the first to third periods t1, t2, and t3 under the control of the above-described timing controller 120 according to the sensing mode, and the pixel P By operating the second second switching transistor Tsw2 in a source follower mode, the threshold voltage of the second switching transistor Tsw2 for each pixel P is sensed through the reference line RL to sense data Sdata. Create (S430), and stores the second threshold voltage data (Vth_Tsw2) for each pixel (P) corresponding to the sensing data (Sdata) of the second switching transistor (Tsw2) for each sensed pixel (P) in the memory 122. (S440).

Then, input image data Idata' for each pixel is generated by aligning input image data Idata according to a display mode to match the driving of the display panel 110, and pixels P stored in the memory 122 Based on the threshold voltage data Vth_Tdr of the star driving transistor Tdr and the threshold voltage data Vth_Tsw2 of the second switching transistor Tsw2, the input data Idata' for each pixel is corrected to obtain the pixel data DATA for each pixel. It is created (S450).

In step S450 according to an example, the first threshold voltage data Vth_Tdr for each pixel P sensed by the previous sensing mode and stored in the memory 122 and the pixel sensed by the first sensing mode and stored in the memory 122 The first characteristic compensation value for each pixel P for compensating for the change in the threshold voltage of the driving transistor Tdr for each pixel P is calculated based on the deviation between the initial threshold voltage data of the driving transistor Tdr for each P Next, the image data Idata of the corresponding pixel P is firstly corrected using the calculated first characteristic compensation value for each pixel P to generate correction data for each pixel. Subsequently, the second threshold voltage data Vth_Tsw2 of the second switching transistor Tsw2 for each pixel P sensed by the immediately preceding sensing mode and stored in the memory 122 and the first pixel for each pixel P corresponding to the correction data 2 The characteristic compensation value θ is extracted from the look-up table 127b, and the correction data of the corresponding pixel P is second-compensated by using the extracted second characteristic compensation value θ for each pixel P, for each pixel Pixel data DATA is generated.

In step S450 according to another example, the first threshold voltage data Vth_Tdr for each pixel P sensed by the previous sensing mode and stored in the memory 122 and the pixel sensed by the first sensing mode and stored in the memory 122 The first characteristic compensation value for each pixel P for compensating for the change in the threshold voltage of the driving transistor Tdr for each pixel P is calculated based on the deviation between the initial threshold voltage data of the driving transistor Tdr for each P Next, the image data Idata of the corresponding pixel P is firstly corrected using the calculated first characteristic compensation value for each pixel P to generate correction data for each pixel. Subsequently, the second threshold voltage data Vth_Tsw2 of the second switching transistor Tsw2 for each pixel P sensed by the previous sensing mode and stored in the memory 122 and the pixels P corresponding to the correction data The coefficients (a, b, c) of the quadratic equation are extracted from a look-up table (127b), and the coefficients (a, b, c) of the quadratic equation for each pixel (P) extracted and the corresponding pixel (P) Pixel data DATA for each pixel is generated according to the calculation result of the quadratic equation using the correction data.

Then, the first and second scan pulses SP1 and SP2 set to the reference high voltage level and the reference low voltage level are supplied to the corresponding scan control line SL and the sensing control line SSL, and each pixel is synchronized with it. An image is displayed on each pixel P by supplying a data voltage Vdata corresponding to the pixel data DATA to the data line DL of the display panel 110 (S460). Here, one scan pulse SP set to a reference high voltage level and a reference low voltage level may be simultaneously supplied to the scan control line SL and the sensing control line SSL.

21A is a diagram showing a histogram of a threshold voltage map and a threshold voltage level of a driving transistor for each pixel sensed by the sensing mode according to the present invention, and FIG. 21B is for each pixel sensed by the sensing mode according to the present invention This is a diagram showing a histogram of a threshold voltage map and a threshold voltage level of the second switching transistor.

21A and 21B, it can be seen that the threshold voltage (Vth_Tsw2) map characteristic and histogram of the second switching transistor for each pixel are similar to the threshold voltage (Vth_Tdr) map characteristic and histogram of the driving transistor.

Accordingly, since the change in the threshold voltage (Vth_Tdr) of the driving transistor included in each pixel and the change in the threshold voltage (Vth_Tsw2) of the second switching transistor are similar to each other, the threshold voltage (Vth_Tdr) of the driving transistor for each pixel is sensed through the sensing mode. , Threshold voltage of the second switching transistor by varying the second high voltage VGH2 of the second scan pulse SP2 supplied to the second switching transistor of each pixel based on the threshold voltage Vth_Tdr of the sensed driving transistor Vth_Tsw2) can be compensated.

22 is a graph showing variations in data voltage according to a threshold voltage change amount of the second switching transistor in the organic light emitting diode display according to the fourth example of the present invention.

As can be seen from FIG. 22, it can be seen that the variation (ㅿVdata) of the data voltage according to the threshold voltage (Vth_Tsw2) of the second switching transistor is minimized for each data voltage (Vdata1 to Vdata9).

Accordingly, the organic light emitting display device according to the fourth example of the present invention corrects the data voltage according to the change amount of the threshold voltages Vth_tdr and Vth_Tsw2 of each of the driving transistor and the second switching transistor, thereby not only the deviation of the threshold voltage of the driving transistor for each pixel but also the pixel The luminance variation of each pixel is minimized due to the threshold voltage variation of the second second switching transistor, thereby improving image quality.

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.

110: display panel 120: timing control
122: memory 125: scan pulse level data generation unit
127: data processing unit 127a: data alignment unit
127b: look-up table 127c: data correction unit
130: power supply 140: row (row) drive unit
142: scan line driver 144: sensing line driver
150: row driving unit 152: data driving unit
154: switching unit 156: sensing unit

Claims (14)

A first switching transistor that outputs a data voltage supplied to the data line according to the first scan pulse supplied to the scan control line, and a second voltage output to the reference line according to the second scan pulse supplied to the sensing control line. A display panel including a plurality of pixels having two switching transistors, a driving transistor outputting a data current corresponding to a difference voltage between the data voltage and the reference voltage, and an organic light emitting element emitting light by the data current;
In the sensing mode, the sensing voltage is sensed by supplying the data voltage to the data line and sensing threshold voltages of any one of the driving transistor and the first and second switching transistors included in each pixel through the reference line. Column driving unit for generating a;
In the display mode, the pixel data corresponding to the image data is supplied to the column driver, and at least one of the high voltage and the low voltage of each of the first and second scan pulses is variable based on the sensing data. A timing control unit generating first and second scan pulse level data;
The first high voltage and the first low voltage of the first scan pulse are generated based on the first scan pulse level data, and the second high voltage of the second scan pulse is based on the second scan pulse level data. And a voltage supply unit generating a second low voltage; And
The first scan pulse is generated and supplied to the scan control line using the first high voltage and the first low voltage, and the second scan pulse is generated using the second high voltage and the second low voltage. An organic light emitting display device including a row driver supplying the sensing control line. According to claim 1,
The timing controller generates the first and second scan pulse level data for operating one of the driving transistor and the first and second switching transistors in a source follower mode in the sensing mode. Organic light emitting display device. According to claim 2,
The timing control unit calculates a compensation reference value based on sensing data of all pixels formed on the display panel, and generates the first and second scan pulse level data based on the calculated compensation reference value. The method according to any one of claims 1 to 3,
The timing controller includes a scan pulse level data generator,
The scan pulse level data generation unit,
A driving time calculating unit calculating a driving time of the first or second switching transistor; And
Based on the sensing data of the first or second switching transistor, a threshold voltage change amount corresponding to the calculated driving time of the first or second switching transistor is calculated, and the first and second switching voltages are calculated according to the calculated threshold voltage change amount. And a scan pulse level setting unit generating second scan pulse level data. The method of claim 4,
The scan pulse level setting unit uses a relational expression for deriving a change in threshold voltage of the first or second switching transistor with respect to the driving time of the first or second switching transistor, or the first or second with respect to the driving time An organic light emitting display device for calculating the amount of change in the threshold voltage using a look-up table to which the amount of change in the threshold voltage of the switching transistor is mapped. A first switching transistor that outputs a data voltage supplied to the data line according to the first scan pulse supplied to the scan control line, and a second voltage output to the reference line according to the second scan pulse supplied to the sensing control line. A display panel including a plurality of pixels having two switching transistors, a driving transistor outputting a data current corresponding to a difference voltage between the data voltage and the reference voltage, and an organic light emitting element emitting light by the data current;
A timing control unit controlling the plurality of pixels in a sensing mode or a display mode;
In response to control of the timing controller according to the sensing mode, the first scan pulse for driving the first switching transistor to be driven in a linear driving mode is generated and supplied to the scan control line, and at the same time, the second switching transistor is saturated. A row driver generating the second scan pulse for driving in a driving mode and supplying the second scan pulse to the sensing control line; And
In response to control of the timing controller according to the sensing mode, a sensing voltage is supplied to the data line, and a sensing voltage is generated by sensing a threshold voltage of the second switching transistor through the reference line to generate the sensing data. An organic light emitting display device including a column driver provided in the display. The method of claim 6,
The high emission voltage of the second scan pulse is lower than the high voltage of the first scan pulse. The method of claim 6,
The timing controller calculates a threshold voltage of the second switching transistor by subtracting and calculating a voltage corresponding to the sensing data from a high voltage of the second scan pulse, and based on the threshold voltage of the second switching transistor. An organic light emitting display device that varies a voltage level of a scan pulse. The method of claim 6,
The column driver responds to the control of the timing controller according to the sensing mode, supplies a sensing data voltage to the data line, and senses threshold data by sensing a threshold voltage of the driving transistor through the reference line. An organic light emitting display device generated and additionally provided to the timing controller. The method of claim 9,
In the display mode, the timing controller generates pixel data by correcting input data based on a threshold voltage of the driving transistor sensed by the sensing mode and a threshold voltage of the second switching transistor,
The column driving unit converts the pixel data into a data voltage in response to control of the timing controller according to the display mode and supplies the data to the data line. The method of claim 10,
The timing control unit,
Compensation data is generated by firstly correcting input data based on a threshold voltage of the driving transistor,
An organic light emitting display device that generates the pixel data by performing secondary correction on the correction data based on a threshold voltage of the second switching transistor and the correction data. The method of claim 11,
The timing controller extracts a threshold voltage of the second switching transistor and a coefficient of a quadratic equation corresponding to the correction data from a look-up table, and calculates a quadratic equation using the extracted coefficient of the quadratic equation and the correction data To perform the second correction of the correction data to generate the pixel data,
The look-up table is an organic light emitting display device in which coefficients of a secondary variable, a coefficient of a primary variable, and a coefficient of a zero-order variable are mapped in advance for each correction data for each threshold voltage of the second switching transistor. . The method of claim 11,
The timing control unit extracts a threshold voltage of the second switching transistor and a characteristic compensation value corresponding to the correction data from a look-up table, and performs the second correction on the correction data using the extracted characteristic compensation value to obtain the pixel data. Create,
The look-up table is an organic light emitting display device in which the characteristic compensation value preset for each correction data is mapped to each threshold voltage of the second switching transistor. The method according to any one of claims 9 to 13,
The scan control line and the sensing control line are electrically connected to each other,
The first scan pulse or the second scan pulse is supplied to the scan control line and the sensing control line connected to each other.

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