KR20170051785A - Organic light emitting display panel, organic light emitting display device, and the method for driving the organic light emitting display device - Google Patents

Abstract

The present invention relates to an organic light emitting display panel, an organic light emitting display, and a driving method thereof. The present invention relates to an organic light emitting display panel which improves luminance deviation and compensates for characteristic value deviation caused by the deterioration of a driving transistor included in the sub pixel of the organic light emitting display panel, and a driving method thereof. According to the present invention, it is possible to compensate for the characteristic value deviation due to the deterioration of the driving transistor, and to compensate for correct mobility in all gradations even if the shape of the I-V curve of the driving transistor is changed. The organic light emitting display further includes a data driver and a gate driver.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display panel, an organic light emitting display device, and a method of driving the same. BACKGROUND ART [0002]

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

BACKGROUND ART [0002] Organic light emitting displays (OLEDs), which have recently been spotlighted as a display device, have advantages of high response speed, high contrast ratio, luminous efficiency, brightness and viewing angle by using an organic light emitting diode (OLED)

In such an organic light emitting diode display, subpixels including an organic light emitting diode and a driving transistor for driving the organic light emitting diode are arranged in a matrix form, and the brightness of the subpixels selected by the scan signal is controlled according to data gradation.

In such an OLED display device, each circuit element such as an organic light emitting diode and a driving transistor in each sub-pixel has a unique characteristic value (e.g., threshold voltage, mobility, etc.). In each driving transistor, degradation progresses according to the driving time, and the inherent characteristic value of the driving transistor may be changed.

Accordingly, the brightness characteristics of the subpixels can be changed according to the change of the characteristic values, and when the characteristic values or the characteristic value changes between the circuit devices are different from each other, the luminance unevenness between the subpixels is caused to cause the luminance uniformity of the organic light emitting display panel to deteriorate Lt; / RTI >

In order to solve such a problem, techniques for sensing and compensating characteristic values for circuit elements in each sub-pixel have been developed.

However, the problem that the characteristic value sensing, which is necessarily required to compensate for the deviation of the characteristic value of the driving transistor, can not be precisely solved is still a problem. In particular, there is a problem that the sensing of mobility, which means the current capability of the driving transistor, is difficult to accurately perform due to various factors, and accurate compensation can not be performed.

It is an object of the present embodiments to provide an organic light emitting display panel, an organic light emitting display, and a driving method thereof that can more accurately perform sensing and compensation of a characteristic value of a driving transistor.

Another object of the present invention is to provide an organic light emitting display panel, an organic light emitting display device, and a driving method thereof, which can precisely sense and compensate a change in a characteristic value of a driving transistor in consideration of a change in shape of an IV curve indicating a characteristic value of a driving transistor .

Another object of the present invention is to improve the accuracy of characteristic value compensation of the driving transistor corresponding to the gradation data voltage by sensing and compensating the characteristic value of the driving transistor by using the voltage in the region where the driving transistor is driven for gradation representation An organic light emitting display panel, an organic light emitting display, and a driving method thereof.

In an embodiment, a plurality of data lines, a plurality of gate lines, and a plurality of sensing lines are disposed, and an organic light emitting display in which a plurality of subpixels, each including an organic light emitting diode and a driving transistor for driving the organic light emitting diode, A data driver for supplying a voltage to the plurality of data lines, and a gate driver for driving the plurality of gate lines, wherein the data driver includes a first transistor for measuring a characteristic value of the driving transistor, And outputting a second voltage during a second period for measuring a characteristic value of the driving transistor.

In this organic light emitting display, a first mobility compensation value of the driving transistor with respect to the first voltage is calculated based on a voltage sensed by the sensing line in the first period, Wherein the first mobility compensation value and the second mobility compensation value are used to calculate a second mobility compensation value of the driving transistor with respect to the second voltage based on a voltage sensed by the first mobility compensation value and the second mobility compensation value, And a memory for storing a mobility compensation value of the driving transistor calculated by the compensator for each voltage outputted in a period for measuring the characteristic value of the driving transistor, And an organic light emitting display device including the organic light emitting display device.

In the organic light emitting diode display, the compensator compensates the mobility of the driving transistor with respect to the data voltage of each gradation output from the data driver using the mobility compensation value of the driving transistor stored in the memory, Compensates the mobility of the driving transistor according to a stored mobility compensation value when the mobility compensation value of the driving transistor with respect to the gradation data voltage outputted by the driver is stored in the memory, The mobility of the driving transistor can be compensated for by using mobility compensation values for two voltages near the data voltage of each gradation among the mobility compensation values stored in the memory.

According to another aspect of the present invention, there is provided an organic light emitting diode display comprising: an organic light emitting display panel having a plurality of data lines, a plurality of gate lines, and a plurality of sensing lines arranged therein and having subpixels each including an organic light emitting diode and a driving transistor for driving the organic light emitting diode; A method of driving an OLED display device including a data driver for supplying a voltage to a plurality of data lines and a gate driver for driving the plurality of gate lines, The data driver outputting a first voltage, the data driver outputting a second voltage during a second period of measuring a characteristic value of the driving transistor, and a step of outputting a voltage sensed by the sensing line in the first period The first mobility compensation of the driving transistor with respect to the first voltage, Storing a second mobility compensation value of the driving transistor with respect to the second voltage calculated based on the voltage sensed by the sensing line in the second period, And compensating the mobility of the driving transistor for the gradation data voltage output by the data driver using the stored second mobility compensation value.

According to another embodiment of the present invention, there is provided an organic light emitting diode display panel including a plurality of data lines, a plurality of gate lines, and a plurality of sensing lines, the organic light emitting display panel including subpixels each including an organic light emitting diode and a driving transistor for driving the organic light emitting diode A data driver for supplying a voltage to the plurality of data lines, and a gate driver for driving the plurality of gate lines, the method comprising: during a first period during which a characteristic value of the driving transistor is measured The data driver outputting a first voltage; the data driver outputting a second voltage during a second period of measuring a characteristic value of the driving transistor; The first mobility compensation value of the driving transistor with respect to the first voltage is set to Calculating a second mobility compensation value of the driving transistor for the second voltage based on a voltage sensed by the sensing line in the second interval; And calculating the mobility compensation value of the driving transistor with respect to the data voltage of each gradation output from the data driver using the second mobility compensation value.

Another embodiment is directed to a liquid crystal display device including a plurality of data lines arranged in a first direction, a plurality of gate lines arranged in a second direction, a plurality of gate lines each including an organic light emitting diode and a driving transistor for driving the organic light emitting diode Wherein the data line is supplied with a first voltage during a first period for measuring a characteristic value of the driving transistor and a second voltage during a second period during which a characteristic value of the driving transistor is measured, A light emitting display panel can be provided.

According to the embodiments, it is possible to provide an organic light emitting display panel, an organic light emitting display, and a driving method thereof that can more accurately perform sensing and compensation of a characteristic value of a driving transistor.

According to these embodiments, there is provided an organic light emitting display panel, an organic light emitting display, and a driving method thereof that can accurately calculate and compensate a compensation value of a driving transistor even if a shape change of an IV curve occurs due to deterioration of a driving transistor .

According to the embodiments, the compensation value is calculated and compensated by using two or more voltages in the region where the driving transistor is driven for the gray level representation, thereby compensating for the characteristic value change of the driving transistor accurately in all the gradations. A panel, an organic light emitting display, and a driving method thereof.

1 is a schematic system configuration diagram of an organic light emitting display according to the present embodiments.
2 is an illustration of a subpixel compensation circuit of the organic light emitting display according to the present embodiments.
FIG. 3 is a diagram illustrating mobility sensing driving according to the present embodiments.
4 is a diagram for explaining the concept of mobility compensation according to the present embodiments.
FIG. 5 is a view for explaining a characteristic value change of the driving transistor according to the present embodiments.
6 is a diagram for describing a change in the characteristic value of the driving transistor according to the present embodiments in detail.
7 is a view showing another embodiment of the mobility sensing drive according to the present embodiments.
8 is a diagram illustrating an example of a section in which mobility sensing according to the present embodiments proceeds.
9 is a diagram for explaining an embodiment of mobility compensation according to the present embodiments.
10 to 12 are flowcharts illustrating a method of driving the OLED display according to the present embodiments.
13 is a view illustrating an organic light emitting display panel according to the present embodiments.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the components from other components, and the terms do not limit the nature, order, order, or number of the components. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening "or that each component may be" connected, "" coupled, "or " connected" through other components.

FIG. 1 is a schematic system configuration diagram of an organic light emitting diode display 100 according to the present embodiments.

1, the OLED display 100 includes a plurality of data lines DL and a plurality of gate lines GL, and a plurality of sub pixels (SP) A data driver 120 for driving the plurality of data lines DL; a gate driver 130 for driving the plurality of gate lines GL; a data driver 120 for driving the plurality of data lines DL; And a timing controller (T-CON, 140) for controlling the gate driver 130 and the like.

The data driver 120 drives the plurality of data lines DL by supplying a data voltage to the plurality of data lines DL.

The gate driver 130 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals to the plurality of gate lines GL.

The timing controller 140 supplies various control signals to the data driver 120 and the gate driver 130 to control the data driver 120 and the gate driver 130.

The timing controller 140 starts scanning according to the timing implemented in each frame, switches the input image data inputted from the outside according to the data signal format used by the data driver 120, and outputs the converted image data And controls the data driving at a proper time according to the scan.

The gate driver 130 sequentially supplies a scan signal of an ON voltage or an OFF voltage to the plurality of gate lines GL under the control of the timing controller 140, Respectively.

The gate driver 130 may be located on one side or both sides of the organic light emitting display panel 110 according to the driving method.

In addition, the gate driver 130 may include one or more gate driver integrated circuits.

Each gate driver integrated circuit may be connected to a bonding pad of the organic light emitting display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) Panel type and may be disposed directly on the organic light emitting display panel 110. In addition, they may be integrated in the organic light emitting display panel 110, or may be implemented in a chip on film (COF) method, which is mounted on a film connected to the organic light emitting display panel 110.

When the specific gate line is opened, the data driver 120 converts the image data received from the timing controller 140 into an analog data voltage and supplies the data voltage to the plurality of data lines DL to drive the plurality of data lines DL do.

The data driver 120 may include at least one source driver integrated circuit to drive a plurality of data lines DL.

Each source driver integrated circuit may be connected to a bonding pad of the organic light emitting display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) Or may be directly disposed on the organic light emitting display panel 110 or integrated on the organic light emitting display panel 110.

In addition, each source driver integrated circuit may be implemented in a chip-on-film (COF) manner. In this case, one end of each source driver integrated circuit is bonded to at least one source printed circuit board, and the other end is bonded to the organic light emitting display panel 110.

The timing controller 140 outputs various timing signals including a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, an input data enable (DE) signal, a clock signal CLK, (E.g., a host system).

The timing controller 140 may switch the input image data inputted from the outside in accordance with the data signal format used by the data driver 120 and output the converted image data so that the data driver 120 and the gate driver 130 A timing signal such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, an input data enable signal DE and a clock signal CLK to generate various control signals, (120) and the gate driver (130).

For example, in order to control the gate driver 130, the timing controller 140 generates a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal GOE : Gate Output Enable), and the like.

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver integrated circuits constituting the gate driver 130. The gate shift clock GSC is a clock signal commonly input to one or more gate driver integrated circuits, and controls the shift timing of the scan signal (gate pulse). The gate output enable signal GOE specifies the timing information of one or more gate driver ICs.

The timing controller 140 includes a source start pulse SSP, a source sampling clock SSC, a source output enable signal SOE, Output enable (DCS) data control signals.

Here, the source start pulse SSP controls the data sampling start timing of one or more source driver integrated circuits constituting the data driver 120. The source sampling clock SSC is a clock signal for controlling sampling timing of data in each of the source driver integrated circuits. The source output enable signal SOE controls the output timing of the data driver 120.

The timing controller 140 is connected to a source printed circuit board to which a source driver integrated circuit is bonded and a control printed circuit (not shown) connected via a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit And may be disposed on a substrate (Control Printed Circuit Board).

A power controller (not shown) for controlling various voltages or currents to supply or supply various voltages or currents to the organic light emitting display panel 110, the data driver 120, the gate driver 130, . These power controllers are also referred to as power management ICs.

Each sub-pixel disposed in the organic light emitting display panel 110 in the organic light emitting diode display 100 may include a circuit element such as an organic light emitting diode (OLED), two or more transistors, and at least one capacitor. have.

The types and the number of the circuit elements constituting each subpixel can be variously determined according to the providing function, the design method, and the like.

Each subpixel in the organic light emitting diode display panel 110 has a characteristic value such as a threshold voltage of the organic light emitting diode OLED and a characteristic value of the driving transistor driving the organic light emitting diode OLED, ), And the like.

2 is an illustration of a subpixel compensation circuit in the organic light emitting display panel 110 according to the present embodiments. And FIG. 3 is a diagram illustrating mobility sensing driving according to the present embodiments.

Referring to FIG. 2, in the organic light emitting display panel 110 according to the present embodiment, each subpixel is one of N subpixels included in i (i = 1, 2,..., 4M) .

Each subpixel includes an organic light emitting diode OLED, a driving transistor DRT for driving the organic light emitting diode OLED, and a first node N1 and a second node N2 of the driving transistor DRT. And a first transistor electrically connected between the first node N1 of the driving transistor DRT and the corresponding data line DL # i, which is controlled by the first scan signal SCAN, And a second transistor SENT which is controlled by the second scan signal SENSE and is electrically connected between the second node N2 of the driving transistor DRT and the corresponding sensing line SL, have.

The organic light emitting diode OLED comprises a first electrode (e.g., an anode electrode or a cathode electrode), an organic layer, and a second electrode (e.g., a cathode electrode or an anode electrode).

For example, the first electrode of the organic light emitting diode OLED may be connected to the second node N2 of the driving transistor DRT, and the second electrode of the organic light emitting diode OLED may be grounded have.

The driving transistor DRT is a transistor for driving the organic light emitting diode OLED by supplying driving current to the organic light emitting diode OLED and includes a second node N2 corresponding to a source node or a drain node, And a third node N3 corresponding to a drain node or a source node.

The first transistor SWT is a transistor for transferring the data voltage VDATAi to the first node N1 of the driving transistor DRT and is connected to the first node N1 of the driving transistor DRT and the data line DL # and is turned on by the first scan signal SCAN applied to the gate node to transfer the data voltage VDATAi to the first node N1 of the driving transistor DRT .

The storage capacitor Cst is electrically connected between the first node N1 and the second node N2 of the driving transistor DRT to maintain a constant voltage for one frame.

The second transistor SENT may be controlled by a second scan signal SENSE electrically connected between the second node N2 of the driving transistor DRT and the sensing line SL and applied to the gate node . The second transistor SENT may be turned on to apply the reference voltage Vref supplied through the sensing line SL to the second node N2 of the driving transistor.

The gate node of the first transistor SWT and the gate node of the second transistor SENT may be connected in common to the same gate line. In this case, the first scan signal SCAN and the second scan signal SENSE are the same gate signal.

Alternatively, the gate node of the first transistor SWT and the gate node of the second transistor SENT may be connected to different gate lines. In this case, the first scan signal SCAN and the second scan signal SENSE are different gate signals.

On the other hand, each driving transistor DRT has a characteristic value such as a threshold voltage (Vth) and a mobility. In addition, each driving transistor DRT may be degraded according to driving time, and its characteristic value may be changed.

Therefore, the difference in the degree of deterioration between the driving transistors DRT is generated according to the difference in driving time between the driving transistors DRT in each sub-pixel, and a characteristic value deviation between the driving transistors DRT may also occur.

Such a characteristic value deviation between the driving transistors DRT may cause a luminance variation between subpixels and may be a major factor causing image quality degradation.

There may be a characteristic value deviation (e.g., a threshold voltage deviation) between the organic light emitting diodes OLED as well as a characteristic value deviation (e.g., a threshold voltage deviation and a mobility deviation) between the driving transistors DRT.

In this specification, a characteristic value deviation between the driving transistors DRT and a characteristic value deviation between the organic light emitting diodes (OLED) are collectively referred to as "sub pixel characteristic value deviation ".

Therefore, in order to improve image quality, it is necessary to compensate for the deviation of sub-pixel characteristic values.

Accordingly, the OLED display 100 according to the present embodiments has a sub-pixel structure for sensing and compensating for a sub-pixel characteristic value variation as shown in FIG. The OLED display 100 according to the present embodiment includes a sensing configuration for sensing a sub-pixel characteristic value deviation for each sub-pixel and a sub-pixel characteristic value deviation compensating for a sub-pixel characteristic value deviation using a result sensed by the sensing configuration Or a compensation configuration that provides

2, the OLED display 100 according to the present embodiment includes a sensing structure for sensing a sub-pixel characteristic value deviation for each sub-pixel, and includes a switch SW And at least one analog digital converter 210 electrically connected to the sensing line SL for sensing the voltage of each sensing line SL and converting the sensed voltage value into a digital value and outputting the digital value.

Such an analog to digital converter (ADC) 210 may be included in the data driver 120. Specifically, at least one analog digital converter 210 may be included in each source driver integrated circuit included in the data driver 120.

The analog digital converter 210 senses the voltage of each sensing line SL, converts the sensed voltage value into a digital value to output sensed data, and the sensed data may be stored in the memory 220.

In addition, the organic light emitting diode display 100 according to the present embodiment has a compensation structure for compensating the deviation of the subpixel characteristic value using the result (sensing data) sensed by the analog digital converter 210 corresponding to the sensing configuration And a compensator 230 for determining a compensation value for compensating the characteristic value deviation of each subpixel based on the sensing data.

The compensator 230 may perform a process of changing data to be supplied to the corresponding subpixel according to the determined compensation value.

The compensator 230 may be included inside or outside the timing controller 140.

The timing controller 140 transfers the data changed by the compensator 230 to the corresponding source driver integrated circuit of the data driver 120.

Accordingly, a digital-to-analog converter (DAC) 240 in the source driver integrated circuit converts the data received from the timing controller 140 into a data voltage VDATAi corresponding to an analog voltage value, .

As described above, using the analog-to-digital converter 210, the compensator 230 can effectively grasp the characteristic value of each subpixel at the digital level.

By implementing the analog digital converter 210 inside the data driver 120, there is an advantage that the sensing configuration of the sub-pixel characteristic value is not separately formed in the organic light emitting display panel 110 or the printed circuit board.

Hereinafter, mobility compensation of the driving transistor DRT will be described with reference to FIG.

3, in order to sense a mobility corresponding to a current capability characteristic except a threshold voltage Vth of the driving transistor DRT, the organic light emitting display 100 includes a driving transistor DRT, The data voltage VDATAi is applied to the first node N1 and the reference voltage Vref is applied to the second node N2 of the driving transistor DRT so that the first node N1 of the driving transistor DRT, And the second node N2.

The organic light emitting diode display 100 initializes the first node N1 and the second node N2 of the driving transistor DRT and then the first node N1 of the driving transistor DRT, (N2) are all floated.

As a result, the voltages of the first node N1 and the second node N2 of the driving transistor DRT rise.

During the voltage rise, a current flows to the sensing line SL via the driving transistor DRT and the second transistor SENT, and the line capacitor Cline on the sensing line SL is charged.

The rate of this voltage rise may vary depending on the current capability of the driving transistor DRT, i.e., the mobility.

As described above, after the voltage is raised for a predetermined time, the sensing line SL and the analog-digital converter 210 are connected by the switch SW.

At this time, the analog digital converter 210 senses the voltage of the sensing line SL, that is, the voltage charged in the line capacitor Cline, and the compensator 230 senses the voltage of the driving transistor DRT based on the sensing voltage Vsen. The current capability, that is, the mobility can be relatively grasped, and a correction gain for compensating mobility can be obtained.

The above-described mobility sensing can proceed at a predetermined timing. For example, the mobility sensing can be performed in real time by allocating a predetermined time (e.g., blank time interval) when the screen is driven.

FIG. 4 illustrates a concept in which the compensator 230 according to the present embodiments compensates the mobility of the driving transistor DRT.

Referring to FIG. 4, the compensator 230 recognizes the current capability, that is, the mobility, of the driving transistor DRT based on the sensing voltage Vsen. At this time, if the mobility is higher or lower than the target mobility, the mobility deviation between the driving transistors DRT may cause image quality deterioration due to the luminance deviation.

Accordingly, the compensator 230 compares the sensed mobility with the target mobility, calculates a gain for correcting the mobility of the sensed driving transistor DRT to the target mobility, and calculates a mobility for the corresponding driving transistor DRT And calculates a compensation value.

The compensator 230 can compensate for the mobility deviation of the driving transistor DRT by performing a process of changing data to be supplied to the corresponding subpixel according to the calculated mobility compensation value.

However, accurate compensation can be performed when the characteristic value change of the driving transistor DRT is only a parallel shift of the I-V curve of the driving transistor DRT and there is no change in the shape.

5 is a view for explaining a characteristic value change of the driving transistor DRT. Reference numeral 510 denotes a case where there is only parallel movement of the IV curve according to deterioration of the driving transistor DRT. Reference numeral 520 denotes a driving transistor And the shape of the IV curve is also changed.

Referring to FIG. 5, it can be seen that the I-V curve moves to the right when deterioration progresses in the I-V curve of the initial driving transistor DRT, as shown at 510. Therefore, a mobility deviation may occur between the driving transistors DRT as it moves to the right side.

Reference numeral 520 denotes a case where a characteristic value change of the driving transistor DRT occurs not only in parallel movement of the I-V curve but also in a shape change. As shown in 520, when the deterioration progresses in the I-V curve of the initial regenerative transistor DRT, the I-V curve moves to the right and the shape of the curve is also changed.

510, the compensator 230 according to the present embodiment can compensate the characteristic value of the driving transistor DRT by a method of calculating the mobility compensation value based on the sensing voltage Vsen and compensating the data.

However, in the case of 520, there is a problem that accurate compensation can not be performed by the above-described method.

6 is a graph for explaining the case of 520. Referring to FIG. 6, the lower graph (solid line, dotted line, left Y-axis) shows the amount of current for each data voltage and the upper graph , The right Y axis) shows the ratio of the amount of current for each data voltage of the initial driving transistor DRT to the amount of current for each data voltage of the driving transistor DRT after deterioration.

6, the solid line portion of the lower graph shows the relationship between the data voltage applied to the initial driving transistor DRT and the amount of current corresponding to the applied data voltage. The dotted line portion of the lower graph shows the relationship between the data voltage applied to the driving transistor DRT after the deterioration and the amount of current corresponding to the applied data voltage. When the solid line portion and the dotted line portion of the lower graph are compared, it can be seen that the amounts of currents for the data voltages of the initial driving transistor DRT and the post-deteriorating driving transistor DRT are different.

Here, it can be seen that the difference in the amount of current for each data voltage between the initial driving transistor DRT and the post-deteriorating driving transistor DRT varies for each data voltage.

For example, the difference 610 between the amount of current of the initial driving transistor DRT and the amount of current of the driving transistor DRT after deterioration at a data voltage of 3 to 4 V and the amount of current and deterioration of the initial driving transistor DRT at a data voltage of 10 V When the difference 602 of the amount of current of the post-driving transistor DRT is compared, it can be seen that the difference is not constant.

6 shows the ratio of the amount of current for each data voltage of the initial driving transistor DRT to the amount of current for each data voltage of the driving transistor DRT after deterioration. In the data voltage of 3 to 4 V, The ratio 603 of the amount of current of the driving transistor DRT after the deterioration to the amount of current of the driving transistor DRT after the deterioration is less than the ratio 604 of the amount of the current of the initial driving transistor DRT and the amount of current of the driving transistor DRT after deterioration, You can see that big.

That is, since the amount of change of the amount of current of the initial driving transistor DRT and the amount of current of the driving transistor DRT after deterioration differs for each data voltage, the mobility of the driving transistor DRT is measured using the fixed data voltage, Compensation for the mobility for voltage may result in insufficient compensation or over compensation for each gray level.

For example, when the mobility compensation value calculated according to the amount of change in the amount of current measured at the data voltage of 10 V is applied to the data voltage of 3 to 4 V, since the amount of change in the amount of current is larger at a data voltage of 3 to 4 V, Can not be. In addition, since the amount of change in the amount of current is different from that of the data voltage of 3V to the data voltage of 3V to 4V, which is the driving region for gradation representation, the amount of change in the amount of current is different from that of the data voltage of 4V. It is not correct to compensate the data voltage of each bank by the calculated mobility compensation value.

In other words, since the amount of change in the amount of current after the deterioration of each data voltage differs, accurate sensing is difficult when the mobility of the driving transistor DRT is measured based on a single fixed sensing voltage Vsen, It may be difficult to compensate the correct mobility for all gradations.

The present embodiments propose a method for enabling accurate mobility compensation even in the case described above.

7 shows mobility compensation of the driving transistor DRT according to the present embodiments.

7, in order to sense the mobility of the driving transistor DRT, the organic light emitting display 100 displays the driving transistor DRT in the first period, which measures the mobility of the driving transistor DRT, A first data voltage DATA1 is applied to the first node N1 of the driving transistor DRT and a reference voltage Vref is applied to the second node N2 of the driving transistor DRT, Thereby initializing the second node N2.

At this time, the first data voltage VDATA1 applied to the first node N1 of the driving transistor DRT may be a voltage (for example, 3V to 5V) in a region where the subpixel is driven for gradation representation.

The organic light emitting diode display 100 initializes the first node N1 and the second node N2 of the driving transistor DRT and then the first node N1 of the driving transistor DRT, (N2) are all floated.

As a result, the voltages of the first node N1 and the second node N2 of the driving transistor DRT are raised, and the driving transistor DRT and the second transistor SENT are turned on The current flows to the sensing line SL. Then, the line capacitor Cline on the sensing line SL is charged.

The sensing line SL and the analog-digital converter 210 are connected by a switch SW after a predetermined time voltage rise.

At this time, the analog digital converter 210 senses the voltage of the sensing line SL, and the compensator 230 determines the first mobility of the driving transistor DRT based on the sensing voltage for the first data voltage VDATA1 do. Then, the compensation value according to the first mobility corresponding to the first data voltage VDATA1 is calculated, and the calculated first mobility compensation value is stored in the memory 220.

The OLED display 100 applies the second data voltage VDATA2 to the first node N1 of the driving transistor DRT in the second period for measuring the characteristic value of the driving transistor DRT, The reference voltage Vref is applied to the second node N2 of the driving transistor DRT to initialize the first node N1 and the second node N2 of the driving transistor DRT, And floats the first node N1 and the second node N2.

At this time, the second data voltage VDATA2 applied to the first node N1 of the driving transistor DRT may be a voltage (for example, 3V to 5V) in a region where the subpixel is driven for gradation representation.

The voltage of each of the first node N1 and the second node N2 of the driving transistor DRT rises and the analog digital converter 210 connected by the switch SW after a predetermined period of time is connected to the sensing line SL, The voltage of the capacitor is sensed.

The compensator 230 grasps the second mobility of the driving transistor DRT based on the sensing voltage for the second data voltage DATA2. Then, the compensation value for the second mobility corresponding to the second data voltage DATA2 is calculated, and the calculated second mobility compensation value is stored in the memory 220.

The first period and the second period for measuring the characteristic value of the driving transistor DRT mean a predetermined period of time dedicated for measuring the characteristic value at the time of driving the screen.

8 illustrates an example of measuring the mobility of the driving transistor DRT according to the present embodiments.

Referring to FIG. 8, a period for measuring a characteristic value of the driving transistor DRT may correspond to a blank time period during a screen driving. According to the embodiments, the first voltage VDATA1 is applied to the first node N1 in the first section, the second voltage VDATA2 is applied to the first node N1 in the second section, And applies the third voltage VDATA3 to the first node N1 in the third period. Therefore, it is possible to prevent an increase in the time required due to the measurement of the mobility with different voltages for each interval for measuring the characteristic value of the driving transistor DRT and the mobility measurement with various data voltages by generating and updating the compensation table.

The first voltage, the second voltage, and the third voltage may be any one of voltages in a region for driving a gray scale representation. For example, the first voltage may be 4V, the second voltage may be 3V, and the third voltage may be 5V.

The compensator 230 stores the first mobility compensation value for the first data voltage DATA1 and the second mobility compensation value for the second data voltage DATA2 in the memory 220, It is possible to compensate the mobility of the driving transistor DRT with respect to the gradation data voltage.

The mobility compensation value for each data voltage may be stored in the memory 220 as shown in Table 1 below.

Vdata 3V 4V Calculated Comp 26 30

The compensator 230 may determine the compensation value according to the data voltage outputted to express the gray level of the subpixel in the data driver 120 and compensate mobility for the data voltage.

For example, when the data driver 120 outputs a data voltage for representing the gray level of 3V, the mobility is compensated according to the mobility compensation value 26 stored in the memory 220. [

At this time, when compensating the mobility for the data voltage in which the measured value does not exist, the compensation value can be calculated using the lever rule.

For example, when the data driver 120 outputs the data voltage for representing the gray level of 3.5V, the mobility compensation value 26 for 3V and the mobility compensation value 30 for 4V are set to 28 (= 26 + ( 30-26) * (0.5 / 1)) is calculated as a mobility compensation value. That is, since the mobility compensation value 26 for 3V and the mobility compensation value 30 for 4V are stored in the memory 220, the mobility compensation value for 3.5V, which is an intermediate value between 3V and 4V, The value 28 can be calculated. Here, the mobility compensation values 26, 28, 30, etc. mean gains for compensating mobility in respective data voltages.

Therefore, according to the embodiments, the mobility compensation value is calculated by sensing two or more data voltages in the region to be driven for gradation representation, and the calculated mobility compensation value is stored to calculate the mobility for the gradation data voltage Compensated by compensating even if the IV characteristic of each gradation is changed.

FIG. 9 shows another embodiment for compensating the mobility according to the present embodiments, and shows a method of calculating the mobility compensation value without generating a compensation table in the memory 220. FIG.

Referring to FIG. 9, the mobility of the driving transistor DRT may be calculated by calculating the mobility compensation value for each data voltage by measuring the mobility of the driving transistor DRT with respect to the two data voltages, .

For example, a first voltage (for example, 5V) is applied to the first node N1 in the first period in which the mobility of the driving transistor DRT is measured. The reference voltage Vref is applied to the second node N2 to initialize the first node N1 and the second node N2 and then the first node N1 and the second node N2 are floated Floating).

When the voltage of the first node N1 and the second node N2 rises and the voltage is sensed through the sensing line SL after a predetermined time and the mobility is measured and the driving transistor DRT Of the first mobility compensation value.

Then, a second voltage (for example, 3 V) is applied to the first node N1 and a reference voltage Vref is applied to the second node N2 in the second period in which the mobility of the driving transistor DRT is measured The second mobility compensation value of the driving transistor DRT with respect to the second voltage is calculated by measuring the mobility with respect to the second voltage as described above.

Then, when compensating the mobility for the data voltage for each bank, the first mobility compensation value for the first voltage and the linear gradient of the second mobility compensation value for the second voltage are used to calculate the shift The compensation value is calculated and the mobility is compensated.

According to this, by not generating a voltage-dependent compensation table, it is possible to improve the accuracy of mobility compensation for each data voltage of each bank while minimizing an increase in the allocated memory.

FIGS. 10 to 12 are flowcharts illustrating a method of driving the OLED display 100 according to the present invention. FIG. 10 shows a process of generating a compensation table for each data voltage. Shows a process of compensating mobility using the generated compensation table. 12 illustrates a process of compensating mobility without generating a compensation table.

10 to 12 show a process of compensating mobility when the driving transistor DRT is deteriorated and the IV curve is distorted. In the initial compensation, as shown in FIG. 3, The compensation value is calculated according to the measured mobility and the mobility compensation is performed.

Referring to FIG. 10, the organic light emitting diode display 100 outputs a first voltage in a first period in which the mobility of the driving transistor DRT is measured (S1000). The first period may correspond to a blank time period when the screen is driven, and the first voltage may correspond to a voltage (for example, 3V to 5V) in a region in which the subpixel is driven to express grayscale.

After the first voltage is output and after a predetermined time, the voltage at the first node N1 of the driving transistor DRT is sensed to calculate the mobility of the driving transistor DRT and the mobility compensation value for the first voltage is calculated (S1010).

In step S1020, whether a mobility compensation value for the first voltage is stored in the memory is stored. If the compensation value for the first voltage is not stored, the compensation value for the first voltage is stored in step S1030. If there is a compensation value for the first voltage, the stored compensation value is updated to the calculated compensation value (S1040).

The organic light emitting diode display 100 outputs a second voltage in a second period for measuring the mobility of the driving transistor DRT (S1050). The second period may correspond to a blank time period during the driving of the screen, and the second voltage may correspond to a voltage (for example, 3V to 5V) in a region in which the subpixel is driven to express grayscale.

The second voltage is outputted and the voltage at the first node N1 of the driving transistor DRT is sensed after a predetermined time to calculate the mobility of the driving transistor DRT and calculate the mobility compensation value for the second voltage (S1060).

It is checked whether the mobility compensation value for the second voltage is stored in the memory 220 in step S1070. If there is no compensation value stored in the memory 220, the mobility compensation value for the second voltage is stored in step S1080. The mobility compensation value for the second voltage is updated with the calculated compensation value (S1090).

Referring to FIG. 11, the organic light emitting diode display 100 displays a mobility diagram for the data voltages of the gradation data output from the data driver 120 using the mobility compensation values for the respective data voltages stored in the memory 220 You can compensate.

The data driver 120 checks the data voltage to be output (S1100) and checks whether the mobility compensation value for the data voltage is stored in the memory 220 (S1110).

If there is a compensation value stored in the memory 220 (YES in S1120), the mobility is compensated with the compensation value (S1130). If there is no stored compensation value (NO in S1120), the compensation value is calculated using the mobility compensation value for the two voltages close to the data voltage, and the mobility is compensated (S1140).

Referring to FIG. 12, the OLED display 100 may calculate a mobility compensation value for two or more data voltages without generating a mobility compensation table for each data voltage, .

The organic light emitting display 100 outputs the first voltage in the first section of the mobility measurement of the driving transistor DRT (S1200). Then, a first compensation value for the first voltage is calculated (S1210).

In operation S1220, the second voltage is output in the second section of the mobility measurement of the driving transistor DRT, and the second compensation value for the second voltage is calculated in operation S1230.

The organic light emitting diode display 100 calculates a linear gradient of a first compensation value for the first voltage and a second compensation value for the second voltage and calculates a mobility for the gradation data voltage output from the data driver 120 The compensation value is calculated and the mobility is compensated (S1240).

13 is a graph illustrating a voltage applied to the first node N1 during the measurement of the mobility of the driving transistor DRT disposed in the organic light emitting display panel 110 and the organic light emitting display panel 110 according to the present embodiments. As shown in FIG.

Referring to FIG. 13, the organic light emitting display panel 110 according to the present embodiment includes a plurality of data lines DL arranged in a first direction, a plurality of gate lines GL arranged in a second direction, And a plurality of subpixels SP arranged in a matrix type and each including an organic light emitting diode OLED and a driving transistor DRT for driving the organic light emitting diode OLED.

13, a first data voltage (for example, 4V) is applied to the first node N1 in a first period in which the mobility of the driving transistor DRT is measured, and the mobility of the driving transistor DRT is set to A second data voltage (for example, 3 V) is applied to the first node N1 in the second section to measure the mobility of the driving transistor DRT and a third data voltage A data voltage (for example, 5V) is applied.

That is, a different voltage is applied to each section for measuring the mobility of the driving transistor DRT to measure the mobility with respect to each voltage and to calculate the compensation value. By using the mobility compensation value for each voltage, it is possible to compensate the mobility with respect to the data voltage of each gradation, so that even when the drift of the driving transistor DRT deteriorates, .

In addition, the mobility of the driving transistor DRT is measured using different voltages in the region for driving the gradation display, and compensation values are applied to compensate for correct mobility in all gradations.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. The embodiments of the present invention are not intended to limit the scope of the present invention but to limit the scope of the present invention.

100: organic light emitting display device 110: organic light emitting display panel
120: Data driver 130: Gate driver
140: timing controller 210: analog-to-digital converter
220: memory 230: compensator
240: Digital to Analog Converters

Claims (15)

An organic light emitting display panel in which a plurality of data lines, a plurality of gate lines, and a plurality of sensing lines are arranged and in which a plurality of subpixels each including an organic light emitting diode and a driving transistor for driving the organic light emitting diode are arranged;
A data driver for supplying a voltage to the plurality of data lines; And
And a gate driver for driving the plurality of gate lines,
The data driver includes:
A first voltage is outputted during a first period in which a characteristic value of the driving transistor is measured and a second voltage different from the first voltage during a second period in which a characteristic value of the driving transistor is measured, And the second section is included in different frames.
The method according to claim 1,
The first mobility compensation value of the driving transistor with respect to the first voltage is calculated on the basis of the voltage sensed by the sensing line in the first section, and the first mobility compensation value of the driving transistor is calculated based on the voltage sensed by the sensing line in the second section And calculating a second mobility compensation value of the driving transistor with respect to the second voltage, using the first mobility compensation value and the second mobility compensation value, And a compensator for calculating a compensation value.
3. The method of claim 2,
And a memory for storing a mobility compensation value of the driving transistor calculated by the compensator for each voltage outputted in a period for measuring a characteristic value of the driving transistor.
The method of claim 3,
Wherein the compensator comprises:
And compensates for the mobility of the driving transistor with respect to the data voltage for each gradation output from the data driver using the mobility compensation value of the driving transistor stored in the memory.
5. The method of claim 4,
Wherein the compensator comprises:
Compensating a mobility of the driving transistor according to a stored mobility compensation value when the mobility compensation value of the driving transistor for the gradation data voltage outputted by the data driver is stored in the memory,
And compensates mobility of the driving transistor by using a mobility compensation value for two voltages closer to the data voltage for each gradation among the mobility compensation values stored in the memory if not stored in the memory.
The method according to claim 1,
Wherein the first voltage and the second voltage are one of data voltages outputted from a region where the data driver drives for gray scale representation.
The method according to claim 1,
Wherein the period for measuring the characteristic value of the driving transistor is a period for measuring the mobility of the driving transistor.
The method according to claim 1,
Wherein the first period and the second period are blank times of frames in which the data driver outputs a data voltage for each gradation.
An organic light emitting display panel including a plurality of data lines, a plurality of gate lines, and a plurality of sensing lines, the organic light emitting display panel including subpixels each including an organic light emitting diode and a driving transistor for driving the organic light emitting diode; And a gate driver for driving the plurality of gate lines, the driving method comprising:
The data driver outputting a first voltage during a first period during which a characteristic value of the driving transistor is measured; And
Wherein the data driver outputs a second voltage different from the first voltage during a second period during which the characteristic value of the driving transistor is measured,
Wherein the first section and the second section are included in different frames.
10. The method of claim 9,
A first mobility compensation value of the driving transistor with respect to the first voltage calculated on the basis of the voltage sensed by the sensing line in the first period, and a second mobility compensation value calculated based on the voltage sensed by the sensing line in the second interval, And storing a second mobility compensation value of the driving transistor for the second voltage.
11. The method of claim 10,
Further comprising compensating for the mobility of the driving transistor with respect to the data voltage for each gradation output by the data driver using the stored first mobility compensation value and the stored second mobility compensation value, .
12. The method of claim 11,
Wherein compensating the mobility of the driving transistor comprises:
If the mobility compensation value for the same voltage as the data voltage for each gradation output from the data driver is not stored, the mobility compensation value for two voltages close to the gradation data voltage is used to calculate the mobility compensation value for the gradation data voltage And compensating the mobility of the driving transistor.
10. The method of claim 9,
Calculating a first mobility compensation value of the driving transistor with respect to the first voltage based on a voltage sensed by the sensing line in the first period;
Calculating a second mobility compensation value of the driving transistor with respect to the second voltage based on a voltage sensed by the sensing line in the second period; And
And calculating the mobility compensation value of the driving transistor with respect to the data voltage for each gradation output from the data driver using the first mobility compensation value and the second mobility compensation value, .
A plurality of data lines arranged in a first direction;
A plurality of gate lines arranged in a second direction;
A plurality of subpixels arranged respectively including an organic light emitting diode and a driving transistor for driving the organic light emitting diode,
Wherein the data line includes:
Wherein the first transistor receives a first voltage during a first period during which a characteristic value of the driving transistor is measured and a second voltage different from the first voltage during a second period during which a characteristic value of the driving transistor is measured, Wherein the second section is included in different frames.
15. The method of claim 14,
Wherein the first voltage and the second voltage are one of data voltages supplied in a region where the subpixel is driven to express grayscale.

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