KR102429321B1 - Organic light emitting display apparatus - Google Patents

Abstract

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic light emitting display device capable of changing the size of a sensing data voltage used in a sensing operation for threshold voltage compensation performed after an image output is cut off. To this end, the organic light emitting diode display according to the present invention includes a panel, a data driver, a gate driver, and a controller. The panel includes pixels, and each of the pixels includes an organic light emitting diode and a pixel driving circuit for driving the organic light emitting diode. The data driver supplies data voltages to data lines provided in the panel, the gate driver sequentially supplies gate pulses to the gate lines, and the controller controls the data driver and the gate driver. When the power-off control signal is detected, the control unit stops the functions of outputting an image, and performs a sensing operation for compensating for a threshold voltage of a driving transistor provided in the pixel driving circuit. When the sensing operation is performed, the data voltage for sensing is supplied to the data line connected to the pixel driving circuit. The horizontal period for sensing in which the sensing data voltage is supplied to the data line is greater than the horizontal period in which the data voltage is output through the data line during the image display period in which an image is output to the panel. In addition, the sensing data voltage is supplied to the data line by at least one unit data voltage output during the sensing horizontal period.

Description

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

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device that performs a sensing operation for threshold voltage compensation according to a power-off control signal.

A Flat Panel Display Apparatus is used in various types of electronic products including mobile phones, tablet PCs, and notebook computers. A flat panel display device (hereinafter, simply referred to as a 'display device') includes a liquid crystal display device (LCD), an organic light emitting display device (OLED), and the like.

In a conventional organic light emitting diode display, a characteristic deviation such as a threshold voltage Vth of a driving transistor occurs for each pixel due to process deviation, deterioration, or the like. Accordingly, the amount of current that drives each organic light emitting diode is different, which causes a luminance deviation between pixels.

In order to solve the above problem, after the power-off control signal is detected, a sensing operation for threshold voltage compensation is performed. The sensing operation is performed immediately or after a predetermined time has elapsed after the output of the image is blocked by the power-off control signal, and is referred to as a Real Time Slow Mode. Therefore, hereinafter, the sensing operation for compensating the threshold voltage is simply referred to as OFF-RS.

FIG. 1 is a table showing values measured when OFF-RS is performed in a conventional organic light emitting display device, and FIG. 2 is a graph showing the magnitude of a sensing data voltage used in the conventional OFF-RS method. In the diagram shown in FIG. 1, (a) shows the existing threshold voltage (Vth) and the existing compensation voltage (Vcomp) measured in the manufacturing stage of the organic light emitting display device, and (b) is the conventional organic light emitting diode display used by the user. Indicates a new threshold voltage (Vth(n+1)) and an error (Verror) measured when OFF_RS is performed in the light emitting display device. In this case, it is assumed that the characteristics of the driving transistor are unchanged.

First, when an organic light emitting display device is manufactured, threshold voltages (hereinafter, simply referred to as 'existing threshold voltages') of driving transistors provided in a panel constituting the organic light emitting display device are measured and stored.

For example, as shown in FIG. 1A , when a sensing data voltage Vsen of 5V is supplied to a data line in order to measure an existing threshold voltage of a driving transistor provided in one pixel. , a sensing voltage Vs_1st of 4.991V may be measured through the sensing line. In this case, the existing threshold voltage Vth of the driving transistor may be 0.009V (=5-4.991). The control unit of the organic light emitting display device stores the existing compensation voltage Vcomp of 0.006V in the storage unit in consideration of the existing threshold voltage Vth. Since the existing compensation voltage Vcomp is stored in units of 6mV, 0.009V is converted to 0.006V, and thus 0.008V is also converted to 0.006V. In this case, if the existing threshold voltage Vth is 0.011V, the existing compensation voltage Vcomp may be 0.012V.

The organic light emitting display device in which the existing compensation voltage Vcomp is stored is sold to the user and then used by the user.

Second, when used by the user, if the OFF-RS condition is met, OFF-RS is performed. In this case, as shown in (b) of FIG. 1 , a sensing data voltage Vsen of 5 V is supplied to the data line connected to the driving transistor, and a sensing voltage Vs_2nd of 4.991 V is applied through the sensing line. can be measured. Accordingly, the variation ΔVth of the threshold voltage of the driving transistor becomes 0.009V (=5-4.991). Accordingly, the new threshold voltage Vth(n+1) of the driving transistor measured in OFF_RS becomes 0.018V (=0.009+0.009).

As described above, since it is assumed that the characteristics of the driving transistor do not change in the manufacturing stage of the organic light emitting diode display, the existing threshold voltage Vth and the new threshold voltage Vth(n+1) have the same value. should be However, an error Verror of -0.009V (=0.009-0.018) occurs between the new threshold voltage Vth(n+1) and the existing threshold voltage Vth.

The error is generated by a difference between a resolution (6mV) of a voltage for calculating the existing compensation voltage (Vcomp) and a resolution (16mV) of the sensing data voltage (Vsen).

For example, as shown in FIGS. 1 and 2 , the sensing voltage (Vs_1st) (X1) received through the sensing line in the manufacturing stage of the organic light emitting display device depends on the characteristics of the analog-to-digital converter (ADC). measured in units of 3 mV. In this case, the existing compensation voltage Vcomp (X2) is stored in the storage unit in units of 6mV. Accordingly, even if the existing threshold voltage Vth (X1) is measured to be 0.009V, the existing compensation voltage Vcomp (X2) becomes 0.006V instead of 0.009V. Also, even if the existing threshold voltage Vth (X1) is measured to be 0.007V, the existing compensation voltage Vcomp (X2) is 0.006V. When the existing threshold voltage Vth (X1) is measured to be 0.011V, the existing compensation voltage Vcomp (X2) may be 0.012V.

In addition, the existing compensation voltage Vcomp (X2) is increased in units of 6 mV, and the sensing data voltage Vsen (Y1) is supplied to the data line to measure the new threshold voltage Vth(n+1). ) is increased in units of 16mV, when the existing compensation voltage Vcomp is 6mV, 5.000V, not 5.006V, must be supplied as the sensing data voltage Vsen (Y1).

Accordingly, an error Verror is generated between the new threshold voltage Vth(n+1) measured using the sensing data voltage Vsen (Y1) and the existing threshold voltage Vth.

In addition, for the reasons described above, in the manufacturing stage of the organic light emitting diode display, driving transistors having different conventional threshold voltages Vth (X1) and different conventional compensation voltages Vcomp (X2) are turned off. When -RS is performed, it may have the same new threshold voltage Vth(n+1).

Accordingly, the external compensation values for the driving transistors having substantially different existing threshold voltages may be equal to each other. That is, an error may be included in the external compensation values.

Accordingly, even when different input image data is input to the pixels provided with the driving transistors, the controller generates the image data using the same external compensation value and transmits the image data to the data driver. The data driver generates data voltages corresponding to the image data and outputs the data voltages to data lines.

Accordingly, an image different from an image intended by the input image data may be output to the panel, and thus, a stain may be generated in the panel.

An object of the present invention, which has been proposed to solve the above problems, is to provide an organic light emitting display device capable of changing the size of a sensing data voltage used in a sensing operation for threshold voltage compensation performed after an image output is cut off. will provide

An organic light emitting diode display device according to the present invention for achieving the above technical problem is a panel including pixels, each of the pixels is provided with an organic light emitting diode and a pixel driving circuit for driving the organic light emitting diode; and a data driver supplying data voltages to data lines provided in the panel, a gate driver sequentially supplying gate pulses to gate lines provided in the panel, and a controller controlling the data driver and the gate driver. When a power-off control signal for blocking the image output from the panel is detected, the controller stops the functions of outputting an image, and performs a sensing operation for compensating a threshold voltage of a driving transistor provided in the pixel driving circuit. do. When the sensing operation is performed, a data voltage for sensing is supplied to a data line connected to the pixel driving circuit. In this case, a horizontal period for sensing in which the sensing data voltage is supplied to the data line is greater than a horizontal period in which a data voltage is output through the data line during an image display period in which an image is output to the panel. In addition, the sensing data voltage is supplied to the data line by at least one unit data voltage output during the sensing horizontal period.

According to the present invention, the difference between the existing compensation voltage calculated and stored during manufacturing of the organic light emitting display device and the sensing data voltage required for the sensing operation for threshold voltage compensation performed after the image output is cut off can be reduced. Accordingly, an error between the new threshold voltage calculated in the sensing operation and the existing threshold voltage calculated during manufacturing may be reduced.

Accordingly, according to the present invention, a sensing error in a sensing operation for threshold voltage compensation performed after an image output is cut off can be reduced.

1 is a table showing values measured when OFF-RS is performed in a conventional organic light emitting diode display.
2 is a graph showing the magnitude of the data voltage for sensing used in the conventional OFF-RS method.
3 is an exemplary view showing the configuration of an organic light emitting display device according to the present invention.
4 is an exemplary diagram illustrating a configuration of a pixel applied to an organic light emitting display device according to the present invention.
5 is an exemplary view showing the configuration of a control unit applied to the organic light emitting display device according to the present invention.
6 is an exemplary diagram illustrating a configuration of a data driver applied to an organic light emitting display device according to the present invention.
7 is an exemplary diagram illustrating a waveform of sensing data applied to an organic light emitting display device according to the present invention.
8 is a table showing values measured when OFF-RS is performed in the organic light emitting diode display according to the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and those of ordinary skill in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention, and the present invention is only defined by the scope of the claims.

It should be noted that in the present specification, in adding reference numbers to the components of each drawing, the same numbers are used for the same components, even if they are indicated on different drawings, as much as possible.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative and the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the case in which the plural is included is included unless specifically stated otherwise.

In interpreting the components, it is interpreted as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal relationship is described as 'after', 'following', 'after', 'before', etc. It may include cases that are not continuous unless this is used.

The term 'at least one' should be understood to include all possible combinations of one or more related items. For example, the meaning of 'at least one of the first item, the second item and the third item' is not only the first item, the second item, or the third item respectively, but also 2 of the first item, the second item and the third item. It means a combination of all items that can be presented from more than one.

Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each embodiment may be independently implemented with respect to each other or implemented together in a related relationship. may be

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is an exemplary view showing the configuration of an organic light emitting display device according to the present invention, FIG. 4 is an exemplary view showing the configuration of a pixel applied to the organic light emitting display device according to the present invention, and FIG. 5 is an organic light emitting display device according to the present invention. It is an exemplary diagram showing a configuration of a control unit applied to a light emitting display device, and FIG. 6 is an exemplary diagram showing a configuration of a data driver applied to an organic light emitting display device according to the present invention.

As shown in FIGS. 3 to 6 , the organic light emitting display device according to the present invention includes pixels (P) 110 , and each of the pixels 110 includes an organic light emitting diode (OLED) and the organic light emitting diode (OLED). A panel 100 including a pixel driving circuit (PDC) for driving a light emitting diode (OLED) is provided, and a data driver 300 for supplying data voltages to data lines DL1 to DLd provided in the panel 100 . , a gate driver 200 that sequentially supplies a gate pulse GP to the gate lines GL1 to GLg provided in the panel 100 , and controlling the data driver 300 and the gate driver 200 . It includes a control unit 400 and a power supply unit 500 for supplying power to the gate driver 200 , the data driver 300 , and the control unit 400 . In particular, when a power-off control signal for blocking the image output from the panel 100 is detected, the control unit 400 stops the functions of outputting the image, and drives the pixel driving circuit (PDC). A sensing operation for compensating the threshold voltage of the transistor Tdr is performed. When the sensing operation is performed, a sensing data voltage Vsen is supplied to the data line DL connected to the pixel driving circuit PDC, and the sensing data voltage Vsen is applied to the data line DL. The horizontal period (ST) for sensing supplied to Vsen) is supplied to the data line DL by at least one unit data voltage Vud output during the sensing horizontal period ST.

First, as shown in FIG. 4 , in the panel 100 , the organic light emitting diode (OLED), a driving transistor (Tdr) for controlling a current flowing through the organic light emitting diode (OLED), and the data line (DL) ) and a pixel driving circuit PDC including a switching transistor Tsw1 connected between the driving transistor Tdr and the gate line GL. In addition, signal lines that define a pixel region in which the pixels 110 are formed and supply a driving signal to the pixel driving circuit PDC are formed on the panel 100 .

In addition, a sensing transistor Tsw2 for external compensation is provided in the pixel driving circuit PDC provided in each of the pixels 110 .

First, the signal lines are the gate line GL, the sensing pulse line SPL, the data line DL, the sensing line SL, a first driving power line PLA, and a second driving power line PLB. includes

Next, the gate lines GL are formed in parallel to have a constant interval along the second direction of the panel 100 , for example, a horizontal direction.

Next, the sensing pulse lines SPL may be formed at regular intervals to be parallel to the gate lines GL. In addition, the gate line GL and the sensing pulse line SPL formed on one horizontal line may be common to form one line.

Next, the data line DL has a predetermined interval along the first direction, for example, a vertical direction, of the panel 100 to intersect each of the gate line GL and the sensing pulse line SPL. can be formed side by side. However, the arrangement structure of the data line DL and the gate line GL may be variously changed.

Next, the sensing line SL may be formed at regular intervals to be parallel to the data lines DL. However, it is not necessarily limited thereto.

At least three of the pixels 110 form one unit pixel 120 . In the following description, the present invention will be described by taking as an example a case in which four pixels 110 (a red pixel, a white pixel, a green pixel, and a blue pixel) form one unit pixel. In this case, one sensing line SL may be formed in the unit pixel. Accordingly, when d data lines DL1 to DLd are formed on a horizontal line of the panel 100 , the number k of the sensing lines SL may be d/4.

In more detail, the data lines are formed in the first direction (vertical direction) of the panel 100 , the sensing lines SL are formed in parallel with the data lines, and the sensing lines ( Each of the SLs may be connected to four pixels 110 constituting each of the unit pixels formed on one horizontal line.

Next, the first driving power line PLA may be formed at regular intervals to be parallel to the data line DL. Here, the first driving power line PLA may be formed at regular intervals to be parallel to the sensing line SL. The first driving power line PLA is connected to the power supply unit 500 to supply the first driving power EVDD supplied from the power supply unit 500 to each pixel 110 .

Next, the second driving power lines PLB may be formed at regular intervals to be parallel to each of the data lines DL1 to DLd or the gate lines GL1 to SLk. The second driving power line PLB supplies the second driving power EVSS supplied from the power supply unit 500 to each pixel 110 . For example, the second driving power lines (PLB) may be electrically grounded to a metal case (or cover) constituting the organic light emitting display device. In this case, the second driving power lines are connected to each pixel ( 110) to provide a grounding power (ground).

Next, each of the plurality of pixels 110 is formed for each pixel area defined by each of the gate lines GL1 to GLg and the data lines DL1 to DLd. Here, each of the plurality of pixels P may be any one of a red pixel, a green pixel, a blue pixel, and a white pixel.

As shown in FIG. 4 , each of the plurality of pixels 110 may include the pixel driving circuit (PDC) and an organic light emitting diode (OLED).

Finally, the pixel driving circuit PDC includes the switching transistor Tsw1, the sensing transistor Tsw2, the driving transistor Tdr, and a capacitor Cst. Here, the transistors Tsw1, Tsw2, and Tdr are thin film transistors (TFTs), and may be a-Si TFTs, poly-Si TFTs, oxide TFTs, organic TFTs, or the like.

The switching transistor Tsw1 is switched by the gate pulse GP to output the data voltage Vdata supplied to the data line DL. To this end, the switching transistor Tsw1 has a gate connected to the adjacent gate line GL, a first electrode connected to the adjacent data line DL, and a first node connected to a first node n1 that is the gate of the driving transistor Tdr. Includes 2 electrodes.

The sensing transistor Tsw2 is switched by the sensing pulse SP and supplies the reference voltage Vref supplied to the sensing line SL to the second node n2 that is the source electrode of the driving transistor Tdr. do. To this end, the sensing transistor Tsw2 includes a gate connected to the adjacent sensing pulse line SPL, a first electrode connected to the adjacent sensing line SL, and a second electrode connected to the second node n2 .

The capacitor Cst is charged with a difference voltage between the voltages supplied to each of the first and second nodes n1 and n2 according to the switching of the switching transistor Tsw1 and the sensing transistor Tsw2, respectively. The driving transistor Tdr is switched according to the voltage.

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

The organic light emitting diode OLED emits light with a luminance corresponding to the data current by emitting light by the data current supplied from the driving transistor Tdr. To this end, the organic light emitting diode OLED includes a first electrode (eg, an anode electrode) connected to the second node n2 , that is, the first electrode of the driving transistor Tdr, and the first electrode and an organic layer formed thereon and a second electrode (eg, a cathode electrode) connected to the organic layer. The second electrode of the organic light emitting diode (OLED) may be the second driving power line PLB formed on the organic layer, or may be additionally formed on the organic layer to be connected to the second driving power line PLB. can

In the above description, the structure of the pixel 110 for performing the external compensation has been described with reference to FIG. 4 , but the structure of the pixel 110 for performing the external compensation may be various in addition to the structure shown in FIG. 4 . structure can be formed.

For example, the external compensation is the amount of change in the threshold voltage or mobility of the driving transistor Tdr formed in the pixel 110 , and the amount of data voltages supplied to the unit pixel according to the change amount is calculated. means to change Accordingly, the structure of the pixel 110 may be changed in various forms so that a change amount of the threshold voltage or mobility of the driving transistor Tdr can be calculated.

In addition, for external compensation, a method of calculating a threshold voltage or mobility change amount of the driving transistor Tdr using the pixel 110 may be variously changed according to the structure of the pixel 110 . .

In more detail, the present invention relates to an organic light emitting display device that cuts off power supplied to a panel on which an image is output when it is determined that an abnormal condition occurs after image output is cut off according to a power-off control signal. Although the present invention is applied to an organic light emitting diode display configured to perform external compensation, the structure and method for performing external compensation are not directly related to the present invention. Accordingly, a pixel structure for external compensation and a method for performing external compensation may include various pixel structures and various external compensation methods currently being proposed for external compensation. For example, the structure and method of the pixel 110 for external compensation and the method of performing external compensation are applied to the structures and methods disclosed in a number of publications including Korean Patent Application Laid-Open No. 10-2013-0066449. In addition, the inventions disclosed in Application No. 10-2013-0150057 and Application No. 10-2013-0149213 filed by the present applicant may also be applied.

That is, a specific structure of a pixel for performing external compensation and a specific method of external compensation are outside the scope of the present invention. Accordingly, an example of a pixel for external compensation has been briefly described with reference to FIG. 4 , and an external compensation method is also briefly described below.

Second, the gate driver 200 sequentially supplies a gate pulse GP to the gate lines GL1 to GLg using the gate control signals GCS transmitted from the controller 400 .

Here, the gate pulse GP refers to a signal capable of turning on the switching transistor Tsw1 connected to the gate lines GL1 to GLg. A signal capable of turning off the switching transistor Tsw1 is referred to as a gate-off signal. The gate pulse GP and the gate-off signal are collectively referred to as a gate signal.

The gate driver 200 is formed independently of the panel 100 and may be connected to the panel 100 through a tape carrier package (TCP) or a flexible printed circuit board (FPCB), but a gate-in panel ( It may be directly mounted in the panel 100 using a Gate In Panel: GIP method.

Third, the power supply unit 500 supplies power to the gate driver 200 , the data driver 300 , and the control unit 400 .

Fourth, as shown in FIG. 5 , the control unit 400 uses a timing synchronization signal TSS input from the external system 900 to control the driving of the gate driver 200 . (GCS) and a data control signal DCS for controlling driving of the data driver 300 are respectively generated.

Also, in the sensing mode in which sensing for external compensation is performed, the controller 400 transmits the sensing image data to be supplied to the pixels formed on the horizontal line on which external compensation is performed to the data driver 300 . Sensing for the external compensation may be performed at various timings, for example, the external compensation may be performed during a blanking period.

The blanking period is inserted between image output periods in which images are output. That is, the blanking period means a period during which an image is not output during one frame period, and the image output period means a period during which an image is output during the one frame period. When a power-on control signal is received from the external system 300 , the organic light emitting diode display is driven, and accordingly, the one frame period is repeated to output an image.

When the power-off control signal transmitted from the external system 300 is detected, the organic light emitting display device stops functions for outputting an image. Accordingly, no image is output from the panel 100 .

However, even if the output of the image is cut off and the image is not displayed to the user, power is supplied to the organic light emitting display device for, for example, 2 to 10 minutes. The organic light emitting display device performs a sensing operation for compensating the threshold voltage of the driving transistors Tdr for 2 to 10 minutes after the output of the image is cut off. The sensing operation is performed for 2 to 10 minutes immediately after the output of the image is blocked by the power-off control signal or after a predetermined time has elapsed, and is referred to as a Real Time Slow Mode. The sensing operation for compensating the threshold voltage is referred to as OFF-RS.

The control unit 400 calculates an external compensation value based on the sensing data Sdata provided from the data driver 300 in the sensing mode, and stores the external compensation value in the storage unit 450 . In addition, the new threshold voltages and the new compensation voltages calculated in the sensing mode are stored in the storage unit 450 . Also, the existing threshold voltages and the existing compensation voltages measured when the organic light emitting diode display device is manufactured may be stored in the storage unit 450 . The storage unit 450 may be included in the control unit 400 , or may be independently formed outside the control unit 400 .

The controller 400 compensates the input image data (Ri, Gi, Bi) transmitted from the external system 900 during the image display period in which the image is output using the external compensation value to convert it into external compensation image data, or Alternatively, the input image data is rearranged without external compensation, and converted into general image data and output. The data driver 300 converts the externally compensated image data or the general image data into a data voltage Vdata, and then supplies the data voltage Vdata to the data line.

In order to perform the function as described above, the controller 400, as shown in FIG. 5, uses the timing synchronization signal TSS transmitted from the external system 900 to A data alignment unit 430 for rearranging input image data Ri, Gi, and Bi and supplying the rearranged image data to the data driver 300, the gate control signal ( GCS), a control signal generator 420 for generating the data control signal DCS and the power control signal PCS, and the pixel (Sdata) using the sensing data Sdata transmitted from the data driver 300. A determination unit 410 for calculating an external compensation value for compensating for a characteristic change of the driving transistor Tdr formed in each of 110), a storage unit 450 for storing the external compensation value, and the data arrangement An output unit 440 for outputting the image data and control signals DCS, PCS, and GCS generated by the unit 430 to the data driver 300 , the gate driver 200 , or the power supply unit 500 . includes

Fifth, the data driver 300 is connected to the data lines DL1 to DLd and the sensing lines SL1 to SLk, and according to a control signal transmitted from the control unit 400 , a sensing mode or a display mode works with The sensing mode and the display mode are executed during a period in which an image is output through the panel 100 according to the power-on control signal.

As shown in FIG. 6 , the data driver 300 includes a data voltage output unit 310 and a sensing unit 320 .

The data voltage output unit 310 is connected to the data lines DL, and the sensing unit 320 is connected to the sensing lines SL.

In the sensing mode, the sensing unit 320 supplies a reference voltage Vref to each of the sensing lines SL1 to SLk, and then receives a signal corresponding to the reference voltage Vref, A change in characteristics of the driving transistor Tdr included in the pixels P formed on the horizontal line is sensed using the signal to generate sensing data Sdata. The sensing unit 320 provides the generated sensing data Sdata to the control unit 400 . The control unit 400 calculates the external compensation value using the sensing data Sdata.

The data voltage output unit 310 converts the image data transmitted from the controller 400, ie, the external compensation image data or the general image data, into a data voltage in the sensing mode to convert the data A voltage is supplied to the data line. In the display mode, the data voltage output unit 310 transmits the image data Data supplied from the control unit 400 in units of horizontal lines by using a plurality of reference gamma voltages supplied from the reference gamma voltage supply unit. It is converted into voltage and supplied to the corresponding data line DL.

In more detail, the data voltage output unit 310 samples the image data Data of each pixel 110 input in units of one horizontal line according to the data control signal DCS, and the plurality of standards Among the gamma voltages, gamma voltages corresponding to the grayscale values of the sampling data are selected as the data voltages and supplied to the data lines DL.

In the sensing mode, the sensing unit 320 senses each sensing voltage received from the sensing lines SL1 to SLk, and generates sensing data Sdata corresponding to the sensing voltage to generate the sensing voltage Sdata, and the control unit 400 ) is provided for To this end, the sensing unit 320 may include an analog-to-digital converter that digitally converts the sensing voltage transmitted from the sensing lines SL1 to SLk to generate the sensing data Sdata. The sensing unit 320 may perform the sensing during the blanking period.

7 is an exemplary diagram illustrating a waveform of sensing data applied to the organic light emitting display device according to the present invention, and FIG. 8 is a table showing values measured when OFF-RS is performed in the organic light emitting display device according to the present invention. to be. In the diagram shown in FIG. 8, (a) shows the existing threshold voltage (Vth) and the existing compensation voltage (Vcomp) measured in the manufacturing stage of the organic light emitting display device, and (b) is the present invention used by the user. A new threshold voltage (Vth(n+1)) and an error (Verror) measured when OFF_RS is performed in the organic light emitting diode display according to FIG. In this case, it is assumed that the characteristics of the driving transistor are unchanged.

As described above, the organic light emitting display device according to the present invention includes the panel 100 , the data driver 300 , the gate driver 300 , the control unit 400 , and the power supply unit 500 . include

The external system 900 is a system for driving an electronic product to which the organic light emitting display device according to the present invention is applied.

For example, when the electronic product is a television, the external system 900 receives audio information and image information through a communication network, and receives the input image data Ri, Gi, and Bi constituting the image information. It is transmitted to the control unit 400 .

When the electronic product is a smartphone, the external system 900 receives audio information or image information through a communication network, generates various audio files and image files, and inputs the image information and the image files. The image data Ri, Gi, and Bi are transmitted to the control unit 400 .

When a power-off control signal for blocking the image output from the panel 100 is detected, the control unit 400 stops the functions of outputting the image.

For example, the controller 400 may not transmit image data to the data driver 300 or may prevent the gate driver 400 from outputting the gate pulse.

After the image output is cut off, the control unit 400 performs a sensing operation OFF-RS for compensating the threshold voltage of the driving transistor Tdr provided in the pixel driving circuit PDC.

When the sensing operation OFF-RS is performed, the sensing data voltage Vsen is supplied to the data line DL connected to the pixel driving circuit PDC.

As shown in FIG. 7 , the sensing horizontal period ST during which the sensing data voltage Vsen is supplied to the data line is the data line ( DL) is greater than the horizontal period 1H in which the data voltage Vdata is output.

In addition, the sensing data voltage Vsen is supplied to the data line DL by at least one unit data voltage Vud output during the sensing horizontal period ST.

In this case, the resolution of the unit data voltage Vud is greater than the resolution of the sensing data voltage Vsen. Here, the resolution means the amount of change in voltage.

For example, the resolution of the unit data voltage Vud is 16 mV, and the resolution of the sensing data voltage Vsen is 6 mV.

Accordingly, the unit data voltage Vud may be changed to 5.016 mV, 5.032 mV, 5.048 mV, or the like. That is, the unit data voltage Vud may increase by 16 mV or decrease by 16 mV.

Also, the sensing data voltage Vsen may be changed to 5.006V, 5.012V, 5.018V, or the like. That is, the sensing data voltage Vsen may increase by 6mV or decrease by 6mV.

In this case, in order to display an image during the image display period, the resolution of the data voltage Vdata supplied to the data line may be the same as or different from the resolution of the unit data voltage Vud.

For example, when the controller 400 generates 8-bit image data and transmits it to the data driver 300 during the image display period, the data driver 300 transmits the 8-bit image data. may be used to generate the data voltage Vdata.

When the OFF-RS is performed, if the control unit 400 transmits 8-bit unit image data to the data driver 300, the data driver uses the 8-bit unit image data to generate the unit data voltage (Vud) can be created. In this case, the resolution of the unit data voltage Vud may be the same as the resolution of the data voltage Vdata.

However, when the OFF-RS is performed, if the controller 400 transmits the unit image data to the data driver 300 using bits smaller than 8 bits, the resolution of the unit data voltage Vud is It may be different from the resolution of the data voltage Vdata.

When the sensing operation OFF-RS is performed, the control unit 400 uses the pre-stored existing threshold voltage Vth and the existing compensation voltage Vcomp to generate a new threshold voltage Vth ( n+1)) is measured.

The control unit 400 generates a new compensation voltage according to the new threshold voltage Vth(n+1), and stores the generated new compensation voltage in the storage unit 400 .

The resolution of the sensing data voltage Vsen is the same as the resolution of the existing compensation voltage Vcomp.

For example, as shown in FIG. 8 , when the resolution of the existing compensation voltage Vcomp is 6mV, the resolution of the sensing data voltage Vsen may also be 6mV. In more detail, when the existing compensation voltage Vcomp increases or decreases by 6 mV, the sensing data voltage Vsen may also increase or decrease by 6 mV.

Since the resolution of the sensing data voltage Vsen is equal to the resolution of the existing compensation voltage Vcomp, the error between the new threshold voltage Vth(n+1) and the existing threshold voltage Vth is reduced. can Accordingly, the quality of the image may be improved.

However, the resolution of the sensing data voltage Vsen is not necessarily the same as the resolution of the existing compensation voltage Vcomp. In more detail, as the resolution of the sensing data voltage Vsen and the resolution of the existing compensation voltage Vcomp become the same, the new threshold voltage Vth(n+1) and the existing threshold voltage Vth ), the resolution of the sensing data voltage Vsen may be set to have a value similar to the resolution of the existing compensation voltage Vcomp as much as possible.

In order to perform the function as described above, the control unit 400 includes the data alignment unit 430 , the control signal generation unit 420 , the determination unit 430 , the storage unit 450 , and the output. part 440 .

The data alignment unit 430 rearranges the input image data Ri, Gi, and Bi transmitted from the external system 900 and supplies the rearranged image data Data to the data driver 300 . In particular, when the sensing operation (OFF-RS) is performed, the data alignment unit 430 generates the unit image data and transmits it to the data driver. The data driver may output the unit data voltage Vud to the data line using the unit image data, and the sensing data voltage Vsen may be generated by the unit data voltage Vud.

In more detail, the data aligning unit 430 is configured to select the unit image data corresponding to the at least one unit data voltage Vud to be supplied to the data line DL during the sensing horizontal period ST. generated, and the unit image data is supplied to the data driver 300 .

The control signal generator 420 generates a gate control signal GCS for controlling the gate driver 200 and a data control signal DCS for controlling the data driver 300 .

In particular, the control signal generator 420 is configured to continuously supply the gate pulse GP to the gate line GL provided in the pixel driving circuit PDC during the sensing horizontal period ST. A gate control signal GCS may be generated and transmitted to the gate driver 200 .

The determination unit 410 determines the new threshold voltage using the sensing data Sdata transmitted from the data driver 300 . The determination unit 410 may store the new compensation voltage calculated by the new threshold voltage Vth(n+1) and the new threshold voltage Vth(n+1) in the storage unit 450 . .

As described above, while an image is output according to the turn-on control signal, the sensing unit 320 senses a threshold voltage or mobility, and transmits the sensing data (Sdata) generated by the sensing result to the control unit. (400).

In addition, the sensing unit 320 performs a sensing operation (OFF) for compensating a threshold voltage of the driving transistor Tdr provided in the pixel driving circuit PDC even while an image is not output according to the turn-off control signal. -RS). The sensing unit 320 transmits the sensing data Sdata generated by the sensing operation OFF-RS for the threshold voltage compensation to the determining unit 410 .

In more detail, the sensing data Sdata may be a signal transmitted from the sensing unit 320 while an image is being output, or may be a signal transmitted from the sensing unit 320 while an image is not being output. However, hereinafter, since the sensing operation OFF-RS for compensating the threshold voltage will be described while no image is output, the sensing data Sdata is transmitted from the sensing unit 320 while no image is output. is a signal to be The sensing data Sdata includes information related to a threshold voltage of the driving transistor Tdr.

The sensing operation (OFF-RS) is briefly summarized as follows.

When the turn-off control signal is received by the organic light emitting display device, the organic light emitting display device stops outputting an image and then performs the sensing operation OFF-RS.

In this case, the switching transistor Tsw1 and the sensing transistor Tsw2 provided in the pixel driving circuit PDC are turned on, and the data line DL provided in the pixel driving circuit PDC is connected to the unit The sensing data voltage Vsen is supplied by the data voltage.

The voltage between the gate and the source of the driving transistor Tdr is increased to a threshold voltage of the driving transistor Tdr by the sensing data voltage Vsen.

The sensing data voltage Vsen and the voltage applied to the driving transistor Tdr are transmitted to the sensing unit 320 through the sensing transistor Tsw2 and the sensing line SL. The analog-to-digital converter (ADC) provided in the sensing unit 320 converts a digital value, that is, the sensing data Sdata, and the sensing data Sdata is transmitted to the control unit 400 . In this case, the analog-to-digital converter (ADC) may calculate the digital value every 3 mV. That is, the resolution of the analog-to-digital converter (ADC) is 3mV.

The external compensation value may be calculated using the sensing data Sdata. For example, a new compensation voltage calculated by the existing compensation voltage Vcomp and the new threshold voltage Vth(n+1) may be set as the external compensation value. When the OFF-RS is terminated, the organic light emitting display device is no longer operated.

Thereafter, when the organic light emitting display device is turned on and an image is output through the panel 100 , the control unit 400 controls the input image data Ri, Gi, Bi inputted from the external system 900 . The image data Data may be generated by summing the external compensation values. Accordingly, the data voltage to which the external compensation value is added in consideration of the change in the threshold voltage of the driving transistor Tdr may be output to the panel 100 . Accordingly, even if the threshold voltage of the driving transistor Tdr is changed, a normal image may be output through the panel 100 .

Hereinafter, a method of driving an organic light emitting display device according to the present invention will be described with reference to FIGS. 3 to 8 . In the following description, the same or similar contents to those described above are omitted or simply described.

First, when the power-on control signal is received from the external system 900 , the organic light emitting diode display starts driving. Accordingly, an image is output from the panel 100 .

Next, when an abnormal condition occurs in the organic light emitting display panel 100 due to various causes and a turn-off control signal is detected or a turn-off control signal is generated by a user's operation, the controller 400 controls the A sensing operation (OFF-RS) is performed.

For example, an abnormal high voltage or a short circuit may occur in the panel 100 , and accordingly, the magnitudes of the gate high voltage and gate low voltage used to generate the gate pulse may be changed to abnormal levels. have. Also, the threshold voltage or mobility of the driving transistor Tdr may be changed to an abnormal level. Also, when the organic light emitting display device performs communication using an Embedded Clock Point-Point Interface (EPI) protocol, a lock signal may not be normally generated and received.

In this case, the organic light emitting display device detects the above-described abnormal condition by performing various protection functions. For example, the organic light emitting diode display may detect an abnormal change in a gate high voltage and a gate low voltage used to generate the gate pulse. Also, the organic light emitting display device may detect an abnormal change in the threshold voltage or mobility of the driving transistor Tdr provided in the panel 100 . Also, the organic light emitting display device may detect that a lock signal is not normally transmitted and received when communication according to the Embedded Clock Point-Point Interface (EPI) protocol is performed.

When the abnormal condition as described above is detected, the control unit 400 stops the function of outputting an image. Accordingly, no image is output from the panel 100 . In this case, a power-off control signal may be transmitted to the control unit 400 from the components detecting the abnormal condition, and the control unit 400 may detect the power-off control signal. For example, the gate driver 200 confirming that the gate high voltage or the gate low voltage is abnormal may transmit the power-off control signal to the controller 400 . Also, the data driver 300 confirming that the lock signal is abnormal may transmit the power-off control signal to the controller 400 . In addition, the data driver 300 confirming that the threshold voltage or the mobility is abnormal may transmit the power-off control signal to the controller 400 . Accordingly, the control unit 400 may detect the power-off control signal transmitted from the gate driver 200 or the data driver 300 .

In addition, the control unit 400 is configured to check information from the gate driver 200 or the data driver 300 that can confirm that the gate high voltage or the gate low voltage is abnormal and that the lock signal is abnormal. It is possible to receive available information, information confirming that the threshold voltage or the mobility is abnormal, and by analyzing the information, it is determined that the gate high voltage VGH or the gate low voltage VGH is abnormal. It may be confirmed, or it may be confirmed that the lock signal is abnormal, or that the threshold voltage or the mobility is abnormal. In this case, the control unit 400 may generate the power-off control signal by itself, and accordingly, the control unit 400 may detect the power-off control signal.

In more detail, the power-off control signal may be detected after being generated by the controller 400 itself, or may be received from external components. Accordingly, the control unit 400 may detect the power-off control signal generated by the detection of the abnormal condition, and when the power-off control signal is received, the control unit 400 stops the function of outputting an image. do.

Also, the control unit 400 may detect the power-off control signal transmitted from the external system 900 . For example, the user may turn off the power switch of an electronic product to which the present invention is applied, for example, a TV, a tablet PC, a notebook computer, and a smart phone. In this case, the external system 900 may transmit the power-off control signal to the controller 400 . When the power-off control signal transmitted from the external system 900 is detected, the control unit 400 stops the function of outputting an image.

In more detail, the power-off control signal may be detected when the abnormal condition occurs, or may be detected when the user voluntarily turns off the power switch of the electronic product to which the present invention is applied. . When the power-off control signal is detected, the control unit 400 stops the function of outputting an image.

Next, even after the output of the image is stopped, for a certain period of time, for example, 2 to 10 minutes, the power supply unit 500 , the control unit 400 , the gate driver 200 and the data driver 400 Power is supplied.

In this case, the controller 400 determines whether a condition for performing the sensing operation OFF-RS for compensating the threshold voltage of the driving transistor Tdr provided in the pixel driving circuit PDC is generated. do. For example, the controller determines a period from when the organic light emitting diode display device is turned on and starts an operation until the output of the image is stopped.

If the period exceeds a preset period, for example, 2 hours, the control unit performs the sensing operation (OFF-RS), and if it does not exceed 2 hours, the control unit does not perform the OFF-RS .

Next, if the condition for performing the sensing operation OFF-RS does not occur as a result of the determination, the power of the organic light emitting diode display is turned off. In this case, the power supplied from the external system 900 to the power supply unit 400 may be cut off.

However, the power supplied from the external system 900 may not be completely cut off. For example, when the presence or absence of a touch of the organic light emitting display device is to be determined while the organic light emitting display device does not output an image, the minimum power required for determining the touch presence is transmitted to the organic light emitting display device. can

Finally, as a result of the determination, when a condition for performing the sensing operation OFF-RS is generated, the controller 400 performs the sensing operation OFF-RS. Hereinafter, the sensing operation OFF-RS will be described.

First, before the sensing operation OFF-RS, that is, in the manufacturing stage of the organic light emitting display device, threshold voltages of driving transistors provided in a panel constituting the organic light emitting display device (hereinafter simply referred to as 'existing threshold voltage') ') are measured and stored.

For example, as shown in FIG. 8A , when the sensing data voltage Vsen of 5V is supplied to the data line to measure the existing threshold voltage of the driving transistor provided in any one pixel. , a sensing voltage Vs_1st of 4.991V may be measured through the sensing line SL. In this case, the existing threshold voltage Vth of the driving transistor may be 0.009V (=5-4.991). The control unit of the organic light emitting display device stores the existing compensation voltage Vcomp of 0.006V in the storage unit in consideration of the existing threshold voltage Vth. Since the existing compensation voltage Vcomp is stored in units of 6mV, 0.009V is converted to 0.006V, and thus 0.008V is also converted to 0.006V. In this case, if the existing threshold voltage Vth is 0.011V, the existing compensation voltage Vcomp may be 0.012V. Accordingly, the resolution of the existing compensation voltage Vcomp is 6mV.

The above-described process is performed for all of the driving transistors Tdr included in the panel 100 . Accordingly, the existing threshold voltages Vth and the existing compensation voltages Vcomp for all of the driving transistors Tdr are stored in the storage unit 450 .

Second, the organic light emitting display device in which the existing compensation voltage Vcomp is stored is sold to the user and then used by the user.

Third, when used by a user, if the OFF-RS condition is met, OFF-RS is performed. In this case, as shown in FIG. 8B , a sensing data voltage Vsen of 5.006V is supplied to the data line connected to the driving transistor.

As shown in FIG. 7 , the sensing data voltage Vsen is supplied to the data line DL during the sensing horizontal period ST.

The sensing horizontal period ST is longer than one horizontal period 1H during which the data voltage Vdata is supplied to the data line during the image display period. 7A and 7B , the horizontal period ST having a length four times the length of the one horizontal period 1H is shown as an example.

As described above, the sensing data voltage Vsen is formed by the unit data voltage Vud. 7A shows the sensing data voltage Vsen generated by one unit data voltage Vud having 5.016V and three unit data voltages having 5V. In this case, the sensing data voltage Vsen may be, for example, 5.006V. In order to generate the sensing data voltage Vsen of 5.006V, one unit data voltage Vud of 5.016V and three unit data voltages of 5V are required during the manufacturing process of the organic light emitting display device. , can be identified through various simulations and tests.

Also, FIG. 7B shows the sensing data voltage Vsen generated by three unit data voltages Vud of 5.016V and one unit data voltage of 5V. In this case, the sensing data voltage Vsen may be, for example, 5.012V. In order to generate the sensing data voltage Vsen of 5.012V, three unit data voltages Vud of 5.016V and one unit data voltage of 5V are required. In the process, it can be identified through various simulations and tests.

In more detail, the relationship between the combination of the unit data voltages Vud and the sensed data voltage Vsen may be identified through various simulations and tests during the manufacturing process of the organic light emitting display device, and the relationship The information on , is stored in the storage unit 450 .

Accordingly, the sensing data voltage may have a value of 5.006V, 5.012V, 5.018V, and the like, and accordingly, the sensing data voltage may have a resolution of 6mV.

When the sensing operation OFF-RS is performed, the control unit 400 checks the existing compensation voltage Vcomp stored in the storage unit 450 . In the example shown in FIG. 8 , since the existing compensation voltage Vcomp is 0.006V, the control unit 400 corresponds to the unit data voltage Vud required to generate the sensing data voltage Vsen of 5.006V. information is extracted from the storage unit 450 .

In this case, since three unit data voltages Vud having 5.016V and one unit data voltage Vud having 5V are required as shown in FIG. The data driver ( 300) is sent.

The data driver 300 has received three unit image data corresponding to three unit data voltages Vud of 5.016V and one unit image data corresponding to one unit data voltage Vud having 5V. ) converts the four unit image data into the four unit data voltages during the four one horizontal periods, and outputs the four unit data voltages to the data line.

Accordingly, unit data voltages as shown in (a) of FIG. 7 may be output, and finally, the sensing data voltages having 5.006V may be supplied to the data line DL.

The unit data voltage Vud is a voltage that can be output from the data driver 300 in the one horizontal period. As described above, the resolution of the unit data voltage Vud may be the same as or different from the resolution of the data voltage output to the data line during the image display period.

In this case, the switching transistor Tsw1 must be maintained in a turned-on state for the four one horizontal periods so that the sensing data voltage can be supplied through the switching transistor Tsw1 during the four one horizontal periods. do.

Accordingly, the control unit 400 generates a gate control signal so that the gate pulse capable of turning on the switching transistor Tsw1 is supplied to the gate of the switching transistor Tsw1 during the four one horizontal periods. to the gate driver 200 .

The gate driver 200 may supply the gate pulse to the switching transistor Tsw1 during the four one horizontal periods in response to the gate control signal.

For example, by varying the width of a clock input from the gate driver 200 to the pull-up transistor from which the gate pulse is outputted to a width corresponding to the four one horizontal periods, the four one horizontal periods During the period, the gate pulse may be continuously supplied to the gate of the switching transistor Tsw1.

Using the method as described above, the sensing pulse SP may also be supplied to the gate of the sensing transistor Tsw2 during the four one horizontal periods.

Accordingly, during the four one horizontal periods, the sensing transistor Tsw2 and the switching transistor Tsw1 are turned on.

Fourth, when the sensing data voltage Vsen is supplied to the data line, the voltage applied to the gate and the source of the driving transistor Tdr by the sensing data voltage Vsen is the sensing transistor Tsw2. ) and the sensing line SL are supplied to the sensing unit 320 .

In this case, the sensing unit 320 may measure a sensing voltage Vs_2nd of 4.997V as shown in FIG. 7B . As described above, the analog-to-digital converter provided in the sensing unit 320 measures the sensing voltage Vs_2nd using a resolution of 3 mV.

The sensing voltage Vs_2nd may be included in the sensing data Sdata. The sensing data Sdata is transmitted to the control unit 400 .

Fifth, the controller 400 calculates a change amount ΔVth of the threshold voltage of the driving transistor by using the sensing voltage Vs_2nd. In the above example, the amount of change ΔVth of the threshold voltage of the driving transistor Tdr may be 0.003V (=5.006-4.009).

The controller 400 may generate the new threshold voltage Vth(n+1) of the driving transistor Tdr by using the change amount ΔVth of the threshold voltage. In the above example, the new threshold voltage Vth(n+1) becomes 0.012V (=0.009+0.003).

As described above, since it is assumed that the characteristics of the driving transistor of the organic light emitting diode display do not change, the existing threshold voltage Vth and the new threshold voltage Vth(n+1) should have the same value. However, an error Verror of -0.003V (=0.009-0.012) occurs between the new threshold voltage Vth(n+1) and the existing threshold voltage Vth.

However, the error (-0.003V) is smaller than the error of -0.009V in the conventional organic light emitting diode display described with reference to FIGS. 1 and 2 .

Therefore, compared with the related art, the quality of the image may be improved.

As described above, the reason that the error (Verror) calculated in the present invention is smaller than the error calculated in the conventional organic light emitting display device is the resolution (6mV) of the voltage for calculating the existing compensation voltage (Vcomp). This is because the resolution (6 mV) of the sensing data voltage Vsen is the same.

Sixth, the control unit 400 calculates the external compensation value using the new threshold voltage Vth(n+1) measured above, and then stores the external compensation value in the storage unit 450 . is saved

Seventh, when the sensing operation (OFF-RS) is completed and the external compensation value is calculated, the power supply unit 500 is supplied to the control unit 400 , the gate driver 200 and the data driver 300 . power is cut off. Accordingly, the power supplied to the organic light emitting display device is turned off.

For example, when the control unit 400 transmits a signal indicating that the sensing operation (OFF-RS) has ended to the external system 900 , the external system 900 is supplied to the power supply unit 500 . The power can be cut off. In this case, as described above, the minimum power required for the organic light emitting display device is supplied through the power supply unit 500 , and the control unit 400 , the gate driver 200 , and the data driver 300 . At least one of them may be supplied.

Eighth, information stored in the storage unit 450 while the sensing operation OFF-RS is performed is used when the organic light emitting diode display is turned on again and driven.

Those skilled in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential characteristics thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

100: panel 200: gate driver
300: data driver 400: timing controller
110: pixel 500: power supply

Claims (5)

a panel having pixels, each of which includes an organic light emitting diode and a pixel driving circuit for driving the organic light emitting diode;
a data driver supplying data voltages to data lines provided on the panel;
a gate driver sequentially supplying gate pulses to gate lines provided on the panel; and
a control unit for controlling the data driver and the gate driver;
When a power-off control signal for blocking the image output from the panel is detected, the controller stops the functions of outputting an image, and performs a sensing operation for compensating a threshold voltage of a driving transistor provided in the pixel driving circuit do,
When the sensing operation is performed, a sensing data voltage is supplied to a data line connected to the pixel driving circuit, and an image is output to the panel during a horizontal sensing period in which the sensing data voltage is supplied to the data line. The organic light emitting diode display is greater than a horizontal period in which a data voltage is output through the data line in the image display period, and the sensing data voltage is supplied to the data line by at least one unit data voltage output in the sensing horizontal period. display device. The method of claim 1,
The resolution of the unit data voltage is greater than the resolution of the sensing data voltage. The method of claim 1,
When the sensing operation is performed, the control unit measures a new threshold voltage of the driving transistor using a pre-stored existing threshold voltage and an existing compensation voltage,
The control unit generates a new compensation voltage according to the new threshold voltage,
The resolution of the data voltage for sensing is the same as the resolution of the existing compensation voltage. 4. The method of claim 3,
The control unit is
a data alignment unit for rearranging input image data transmitted from an external system and supplying the rearranged image data to the data driver;
a control signal generator configured to generate a gate control signal for controlling the gate driver and a data control signal for controlling the data driver; and
a determination unit for determining the new threshold voltage using the sensed data transmitted from the data driver;
The data aligning unit generates unit image data corresponding to at least one unit data voltage to be supplied to the data line in the horizontal period for sensing, and supplies the unit image data to the data driver. 5. The method of claim 4,
The control signal generator generates a gate control signal for continuously supplying the gate pulse to a gate line provided in the pixel driving circuit during the horizontal period for sensing and transmits the generated gate control signal to the gate driver.

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