KR102492335B1 - Organic light-emitting display device, and compensation method of organic light-emitting display device - Google Patents

Abstract

The present embodiments relate to a compensation technology for an organic light emitting display device, and more particularly, calculates an n-th mobility compensation value from an n-th mobility sensing value and senses a th mobility compensation value in an n+1 th mobility sensing section. The n+1 th mobility sensing data of the driving transistor is generated based on the calculated n th mobility compensation value so that the n+1 mobility sensing value has a certain ratio according to the mobility characteristics. The present invention relates to an organic light emitting display device that outputs an output to a section and calculates an n+1 th mobility compensation value from an n+1 th mobility sensing value, and a compensation method thereof.

Description

Organic light emitting display device and its compensation method

The present embodiments relate to a compensation technology of an organic light emitting display device displaying an image.

Recently, an organic light emitting display device that has been in the limelight as a display device uses an organic light-emitting diode (OLED) that emits light by itself, and has advantages such as fast response speed, luminous efficiency, luminance, and viewing angle.

In such an organic light emitting display device, subpixels including organic light emitting diodes are arranged in a matrix form, and brightness of subpixels selected by a scan signal is controlled according to gray levels of data.

Each subpixel of the organic light emitting display device may include an organic light emitting diode and a driving transistor driving the organic light emitting diode.

Meanwhile, the driving transistor in each subpixel has unique characteristics such as threshold voltage and mobility. The unique characteristics of each of these driving transistors may change as degradation progresses according to driving time.

Because of this, a difference in the degree of deterioration between driving transistors occurs according to a difference in driving time between driving transistors in each subpixel, and characteristic value deviations between driving transistors may also occur.

The characteristic value deviation between the driving transistors may cause a luminance deviation between subpixels, which may be a major factor in deteriorating image quality.

Accordingly, various technologies have been developed to compensate for deviations in characteristic values between driving transistors.

Nevertheless, the problem of inability to accurately sense characteristic values, which is essential for compensating for variation in characteristic values between driving transistors, is still not being solved.

In particular, it is difficult to accurately perform sensing of mobility, which means the current capability of the driving transistor, due to various factors.

An object of the present embodiments is to provide an organic light emitting display device capable of more accurate mobility compensation and a compensation method thereof.

Another object of the present embodiments is to provide an organic light emitting display device capable of suppressing both a luminance deviation due to initial mobility characteristic deviation and a luminance change due to mobility characteristic change, and a method for compensating the same.

In one aspect, the present embodiments provide a display panel having a plurality of data lines, a plurality of gate lines and a plurality of subpixels, a data driver driving the plurality of data lines, and a display panel driving the plurality of gate lines. An organic light emitting display device including a gate driver and a controller controlling the data driver and the gate driver may be provided.

In such an organic light emitting display device, each subpixel includes an organic light emitting diode, a driving transistor driving the organic light emitting diode, and a storage capacitor electrically connected between a first node and a second node of the driving transistor.

The organic light emitting display device may further include a sensing unit that senses the voltage of the first node of the driving transistor in a mobility sensing period of the driving transistor and outputs a digital mobility sensing value for the sensed voltage. there is.

In the nth mobility sensing period of the driving transistor, the sensing unit senses the voltage of the first node of the driving transistor to output the nth mobility sensing value, and in the n+1th mobility sensing period of the driving transistor, The n+1 th mobility sensing value may be output by sensing a voltage of a first node of the driving transistor.

The controller calculates an n-th mobility compensation value from the n-th mobility sensing value, and the n + 1 th mobility sensing value sensed in the n + 1 th mobility sensing section has a certain ratio according to the mobility characteristic, Based on the calculated n-th mobility compensation value, n+1-th mobility sensing data is generated and output to the n+1-th mobility sensing section of the driving transistor, and the n+1-th mobility sensing data is calculated from the n+1-th mobility sensing value. A mobility compensation value may be calculated.

In another aspect, the present embodiments may include generating mobility sensing data for sensing mobility of a driving transistor in a subpixel, outputting the mobility sensing data to a data driver, and using the mobility sensing data. receiving a mobility-sensed value corresponding to a result of sensing the mobility of a driving transistor in a sub-pixel; calculating a mobility compensation value based on the mobility-sensed value; and updating a mobility compensation value previously stored in a memory with the calculated mobility compensation value.

In this compensation method, in the step of generating the mobility sensing data, the mobility sensing value sensed in the mobility sensing section based on the previously calculated mobility compensation value has a certain ratio according to the mobility characteristic. It can also generate data for sensing.

According to the present embodiments as described above, it is possible to provide an organic light emitting display device capable of more accurate mobility compensation and a compensation method thereof.

In addition, according to the present embodiments, it is possible to provide an organic light emitting display device capable of suppressing both the luminance deviation due to the initial mobility characteristic deviation and the luminance change due to the mobility characteristic change, and a method for compensating the same.

1 is a system configuration diagram of an organic light emitting display device according to the present embodiments.
2 is an exemplary diagram of a sub-pixel structure of an organic light emitting display device according to the present embodiments.
3 is a diagram illustrating another sub-pixel structure and a compensation circuit of an organic light emitting display device according to the present embodiments.
4 is a diagram illustrating a threshold voltage sensing driving method of a driving transistor in an organic light emitting display device according to the present embodiments.
5 is a diagram illustrating a mobility sensing driving method of a driving transistor in an organic light emitting display device according to example embodiments.
6 is a diagram exemplarily illustrating sequences of threshold voltage sensing and mobility sensing in an organic light emitting display device according to the present embodiments.
7 is a timing diagram illustrating threshold voltage sensing and mobility sensing in an organic light emitting display device according to the present embodiments.
8A is a diagram for explaining generation of mobility sensing data for mobility sensing driving and calculation of a mobility compensation value based on a mobility sensing value in an organic light emitting display device according to the present embodiments.
8B illustrates compensating image data for displaying an image with a mobility compensation value α_comp′ calculated based on a mobility sensing value α_sen in the organic light emitting display device 100 according to the present embodiments. It is a drawing for
9 is a diagram illustrating mobility compensation through mobility sensing and reduction of mobility deviation according to mobility compensation in the organic light emitting display device according to the present embodiments.
10 is a graph showing a relationship between mobility sensing values according to mobility characteristics for all subpixels of the same color in an organic light emitting display panel and after mobility compensation in an organic light emitting display device 100 according to the present embodiments. is a diagram showing the relationship between mobility sensing values according to mobility characteristics.
FIG. 11 is a diagram illustrating a relationship between luminance according to mobility characteristics when an image is displayed in a display section by applying the relationship between mobility sensing values according to mobility characteristics after mobility compensation of FIG. 10 .
12 is a graph showing a relationship between mobility sensing values according to a change in mobility characteristics and mobility compensation for all subpixels of the same color in an organic light emitting display panel in the organic light emitting display device 100 according to the present embodiments. Hereafter, it is a diagram showing the relationship between a mobility sensing value and luminance according to mobility characteristics.
13 is a graph illustrating a relationship between a mobility sensing value according to a change in mobility characteristics and a result after mobility compensation for any one subpixel in an organic light emitting display panel in the organic light emitting display device 100 according to the present embodiments. It is a diagram showing the relationship between mobility sensing values according to mobility characteristics.
FIG. 14 is an organic light emitting display according to the present embodiments, when an image is displayed in a display section by applying the relationship between mobility sensing values according to mobility characteristics after the mobility compensation of FIG. In the apparatus 100, the relationship between the mobility sensing value according to the mobility characteristic change for any one subpixel in the organic light emitting display panel, and the mobility sensing value and luminance according to the mobility characteristic after mobility compensation It is a diagram showing the relationship.
16 is a graph showing a relationship between mobility sensing values according to a change in mobility characteristics and mobility compensation for all subpixels of the same color in the organic light emitting display panel in the organic light emitting display device 100 according to the present embodiments. Hereafter, it is a diagram showing the relationship between a mobility sensing value and luminance according to mobility characteristics.
FIG. 17A shows generation of mobility sensing data for mobility sensing driving shown in FIG. 16 and mobility compensation based on the mobility sensing value α_sen in the organic light emitting display device 100 according to the present embodiments. It is a diagram for explaining the calculation of the value (α_comp').
FIG. 17B shows image data for displaying an image with the mobility compensation value α_comp′ calculated based on the mobility sensing value α_sen shown in FIG. 16 in the organic light emitting display device 100 according to the present embodiments. It is a drawing for explaining compensation.
18 is a flowchart of a compensation method of the organic light emitting display device 100 according to the present embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention are described in detail below with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

Also, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present invention. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is or may be directly connected to that other element, but intervenes between each element. It will be understood that may be "interposed", or each component may be "connected", "coupled" or "connected" through other components.

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

Referring to FIG. 1 , in an organic light emitting display device 100 according to the present embodiments, a plurality of data lines DL and a plurality of gate lines GL are disposed, and a plurality of sub pixels (SP) The organic light emitting display panel 110, the data driver 120 driving the plurality of data lines DL, the gate driver 130 driving the plurality of gate lines GL, and the data driver 120 ) and the controller 140 controlling the gate driver 130.

The controller 140 controls the data driver 120 and the gate driver 130 by supplying various control signals to the data driver 120 and the gate driver 130 .

The controller 140 starts scanning according to the timing implemented in each frame, converts input image data input from the outside to suit the data signal format used by the data driver 120, and outputs the converted image data. , data drive is controlled at an appropriate time according to the scan.

The controller 140 may be a timing controller used in a typical display technology or a control device that further performs other control functions including a timing controller.

The data driver 120 drives the plurality of data lines DL by supplying data voltages to the plurality of data lines DL. Here, the data driver 120 is also referred to as a 'source driver'.

The gate driver 130 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals to the plurality of gate lines GL. Here, the gate driver 130 is also referred to as a 'scan driver'.

The gate driver 130 sequentially supplies scan signals of an on voltage or an off voltage to the plurality of gate lines GL under the control of the controller 140 .

When a specific gate line is opened by the gate driver 130, the data driver 120 converts the image data received from the controller 140 into analog data voltages and supplies them to a plurality of data lines DL.

The data driver 120 is located on only one side (eg, upper or lower side) of the organic light emitting display panel 110 in FIG. : upper side and lower side) may be located both.

The gate driver 130 is located on only one side (eg, the left or right side) of the organic light emitting display panel 110 in FIG. Example: left and right) may be located on both sides.

The above-described controller 140 includes various types of input image data, including a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input data enable (DE) signal, a clock signal (CLK), and the like. Receive timing signals from outside (e.g. host system).

The controller 140 converts the input image data input from the outside to suit the data signal format used by the data driver 120 and outputs the converted image data, as well as the data driver 120 and the gate driver 130. In order to control, the data driver 120 and the gate driver 130 generate various control signals by receiving timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input DE signal, and a clock signal. output as

For example, in order to control the gate driver 130, the controller 140 includes a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE: It outputs various gate control signals (GCS: Gate Control Signal) including 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 shift timing of scan signals (gate pulses). The gate output enable signal GOE specifies timing information of one or more gate driver integrated circuits.

In addition, the controller 140, in order to control the data driver 120, a source start pulse (SSP: Source Start Pulse), a source sampling clock (SSC: Source Sampling Clock), a source output enable signal (SOE: Source Output It outputs various data control signals (DCS) including Enable) and the like.

Here, the source start pulse SSP controls 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 that controls sampling timing of data in each source driver integrated circuit. The source output enable signal SOE controls output timing of the data driver 120 .

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

Each source driver integrated circuit (SDIC) is attached 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) method. It may be connected to, directly disposed on the organic light emitting display panel 110, or may be integrated and disposed on the organic light emitting display panel 110 in some cases. In addition, each source driver integrated circuit (SDIC) may be implemented in a Chip On Film (COF) method mounted on a film connected to the organic light emitting display panel 110 .

Each source driver integrated circuit (SDIC) may include a latch circuit, a digital to analog converter (DAC), an output buffer, and the like.

In some cases, each source driver integrated circuit (SDIC) may further include an analog to digital converter (ADC).

The gate driver 130 may include at least one gate driver integrated circuit (GDIC).

Each gate driver integrated circuit (GDIC) is 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) method, or is connected to a gate in panel (GIP) method. ) type and directly disposed on the organic light emitting display panel 110, or may be integrated and disposed on the organic light emitting display panel 110 in some cases. In addition, each gate driver integrated circuit (GDIC) may be implemented in a chip on film (COF) method mounted on a film connected to the organic light emitting display panel 110 .

Each gate driver integrated circuit (GDIC) may include a shift register, a level shifter, and the like.

The organic light emitting display device 100 according to the present embodiments includes at least one source printed circuit board (S-PCB) required for circuit connection to at least one source driver integrated circuit (SDIC) and It may include a control printed circuit board (C-PCB) for mounting control parts and various electric devices.

At least one source driver integrated circuit (SDIC) may be mounted on the at least one source printed circuit board (S-PCB), or a film having at least one source driver integrated circuit (SDIC) mounted may be connected.

On the control printed circuit board (C-PCB), the controller 140 for controlling operations of the data driver 120 and the gate driver 130, the organic light emitting display panel 110, the data driver 120, and the gate driver A power controller that supplies various voltages or currents to 130 or the like or controls various voltages or currents to be supplied may be mounted.

The at least one source printed circuit board (S-PCB) and the control printed circuit board (C-PCB) may be circuitically connected through at least one connecting member.

Here, the connecting member may be a flexible printed circuit (FPC) or a flexible flat cable (FFC).

At least one source printed circuit board (S-PCB) and one control printed circuit board (C-PCB) may be integrated into one printed circuit board.

Each subpixel SP disposed on the organic light emitting display panel 110 may include a circuit element such as a transistor.

For example, each sub-pixel SP may include circuit elements such as organic light-emitting diodes (OLEDs) and driving transistors for driving them.

The type and number of circuit elements constituting each sub-pixel SP may be variously determined according to a provided function and a design method.

2 is an exemplary diagram of a sub-pixel structure of the organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 2 , in the organic light emitting display device 100 according to the present embodiments, each subpixel basically includes an organic light-emitting diode (OLED) and an organic light emitting diode (OLED). The driving transistor (DRT: Driving Transistor), the switching transistor (SWT: Switching Transistor) for transferring the data voltage to the second node (N2) corresponding to the gate node of the driving transistor (DRT), and the image signal voltage It may include a storage capacitor (Cstg) that maintains a corresponding data voltage or a corresponding voltage for one frame time.

An organic light emitting diode (OLED) may include a first electrode (eg, an anode electrode), an organic layer, and a second electrode (eg, a cathode electrode).

The driving transistor DRT drives the organic light emitting diode (OLED) by supplying a driving current to the organic light emitting diode (OLED).

The first node N1 of the driving transistor DRT may be electrically connected to the first electrode of the organic light emitting diode OLED, and may be a source node or a drain node. The second node N2 of the driving transistor DRT may be electrically connected to a source node or a drain node of the switching transistor SWT and may be a gate node. The third node N3 of the driving transistor DRT may be electrically connected to a driving voltage line (DVL) supplying the driving voltage EVDD, and may be a drain node or a source node.

The driving transistor DRT and the switching transistor SWT may be implemented as n-type or p-type as in the example of FIG. 2 .

The switching transistor SWT is electrically connected between the data line DL and the second node N2 of the driving transistor DRT, and can be controlled by receiving the scan signal SCAN to the gate node through the gate line. .

The switching transistor SWT may be turned on by the scan signal SCAN to transfer the data voltage Vdata supplied from the data line DL to the second node N2 of the driving transistor DRT.

The storage capacitor Cstg may be electrically connected between the first node N1 and the second node N2 of the driving transistor DRT.

The storage capacitor Cstg is not a parasitic capacitor (eg, Cgs or Cgd) that is an internal capacitor existing between the first node N1 and the second node N2 of the driving transistor DRT, but It is an external capacitor intentionally designed outside the driving transistor (DRT).

Meanwhile, in the case of the organic light emitting display device 100 according to the present exemplary embodiments, as the driving time of each subpixel SP is increased, circuit elements such as an organic light emitting diode (OLED) and a driving transistor (DRT) Degradation may proceed.

Accordingly, inherent characteristic values (eg, threshold voltage, mobility, etc.) of circuit elements such as organic light emitting diodes (OLEDs) and driving transistors (DRTs) may change.

A change in the characteristic value of such a circuit element causes a change in luminance of a corresponding subpixel. Accordingly, the change in the characteristic value of a circuit element may be used as the same concept as the change in luminance of a subpixel.

In addition, the degree of change in characteristic values between circuit elements may be different depending on the degree of deterioration of each circuit element.

Differences in characteristic values between circuit elements cause luminance deviations between subpixels. Accordingly, the characteristic value deviation between circuit elements may be used as the same concept as the luminance deviation between subpixels.

The above-described change in luminance of a subpixel and deviation in luminance between subpixels may cause problems such as deterioration in accuracy of luminance expressive power of a subpixel or occurrence of an abnormal screen phenomenon.

Here, the characteristic value of the circuit element (hereinafter, also referred to as “sub-pixel characteristic value”) may include, for example, the threshold voltage and mobility of the driving transistor DRT. In some cases, the organic light emitting diode (OLED) may include a threshold voltage of

The organic light emitting display device 100 according to the present embodiments includes a sensing function for sensing (measuring) a subpixel luminance change and a luminance deviation between subpixels (variation in characteristic values of circuit elements and deviations in characteristic values between circuit elements), and sensing results. It is possible to provide a compensation function for compensating for subpixel luminance change and luminance deviation between subpixels.

The organic light emitting display device 100 according to the present embodiments includes a subpixel structure suitable for the sensing and compensating function for a subpixel luminance change and a luminance deviation between subpixels, and a sensing and compensating structure. Compensation circuit included.

3 is an exemplary view of another sub-pixel structure and compensation circuit of the organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 3 , each subpixel disposed on the organic light emitting display panel 110 according to the present embodiments includes, for example, an organic light emitting diode (OLED), a driving transistor (DRT), a switching transistor (SWT), and a storage device. In addition to the capacitor Cstg, a sensing transistor (SENT) may be further included.

Referring to FIG. 3 , the sensing transistor SENT is electrically connected between the first node N1 of the driving transistor DRT and a reference voltage line (RVL) supplying a reference voltage (Vref). connected, and can be controlled by receiving a sensing signal SENSE, which is a kind of scan signal, as a gate node.

The sensing transistor SENT is turned on by the sensing signal SENSE and applies the reference voltage Vref supplied through the reference voltage line RVL to the first node N1 of the driving transistor DRT.

Also, the sensing transistor SENT may be used as one of the voltage sensing paths for the first node N1 of the driving transistor DRT.

Meanwhile, the scan signal SCAN and the sensing signal SENSE may be separate gate signals. In this case, the scan signal SCAN and the sensing signal SENSE may be respectively applied to the gate node of the switching transistor SWT and the gate node of the sensing transistor SENT through different gate lines.

In some cases, the scan signal SCAN and the sensing signal SENSE may be the same gate signal. In this case, the scan signal SCAN and the sensing signal SENSE may be commonly applied to the gate node of the switching transistor SWT and the gate node of the sensing transistor SENT through the same gate line.

Referring to FIG. 3 , the organic light emitting display device 100 according to the present exemplary embodiments senses a change in subpixel characteristic values (a driving transistor characteristic value, an organic light emitting diode characteristic value) and/or a deviation between subpixel characteristic values to sense data. A sensing unit 310 that outputs , a memory 320 that stores sensing data, and a compensation unit that performs a compensation process for compensating for changes in subpixel characteristic values and/or deviations between subpixel characteristic values using the sensing data ( 330) and the like.

The sensing unit 310 may be implemented by including at least one analog to digital converter (ADC).

Each analog to digital converter (ADC) may be included inside the source driver integrated circuit (SDIC), and in some cases may be included outside the source driver integrated circuit (SDIC).

The compensating unit 330 may be included inside the controller 140 and, in some cases, may be included outside the controller 140 .

Sensing data output from the sensing unit 310 may be, for example, in a Low Voltage Differential Signaling (LVDS) data format.

In the organic light emitting display device 100 according to the present embodiments, in order to control sensing driving, that is, the voltage application state of the first node N1 of the driving transistor DRT in the subpixel SP is a subpixel characteristic value. In order to control a state necessary for sensing, a first switch SW1 and a second switch SW2 may be further included.

Whether or not to supply the reference voltage Vref to the reference voltage line RVL may be controlled through the first switch SW1.

When the first switch SW1 is turned on, the reference voltage Vref is supplied to the reference voltage line RVL and connected to the first node N1 of the driving transistor DRT through the turned-on sensing transistor SENT. ) can be authorized.

Meanwhile, when the voltage of the first node N1 of the driving transistor DRT becomes a voltage state reflecting the subpixel characteristic value, a reference voltage line (which may be of equal potential to the first node N1 of the driving transistor DRT) RVL) may also become a voltage state reflecting subpixel characteristic values. At this time, a voltage reflecting the subpixel characteristic value may be charged in the line capacitor Csen formed on the reference voltage line RVL.

When the voltage of the first node N1 of the driving transistor DRT becomes a voltage state reflecting the subpixel characteristic value, the second switch SW2 is turned on, and the sensing unit 310 and the reference voltage line RVL are turned on. this can be connected.

Accordingly, the sensing unit 310 senses the voltage of the reference voltage line RVL, that is, the voltage of the first node N1 of the driving transistor DRT, which is a voltage state reflecting the subpixel characteristic value. Here, the reference voltage line (RVL) is also described as a “sensing line”.

For example, one such reference voltage line RVL may be disposed in each subpixel column, or one in each of two or more subpixel columns.

For example, if one pixel is composed of 4 sub-pixels (red sub-pixel, white sub-pixel, green sub-pixel, blue sub-pixel), the reference voltage line RVL is composed of 4 sub-pixel columns (red sub-pixel column). , a white subpixel column, a green subpixel column, and a blue subpixel column) may be arranged one by one for each pixel column including.

When the sensing unit 310 is connected to the reference voltage line RVL, the voltage of the first node N1 of the driving transistor DRT (the voltage of the reference voltage line RVL or the line on the reference voltage line RVL) The voltage charged in the capacitor Csen) is sensed.

The voltage sensed by the sensing unit 310 is a voltage value (Vdata-Vth or Vdata-ΔVth) including the threshold voltage (Vth) or threshold voltage deviation (ΔVth) of the driving transistor (DRT), or the driving transistor (DRT). It may be a voltage value for sensing the mobility of .

Below, threshold voltage sensing driving and mobility sensing driving of the driving transistor DRT will be briefly described.

First, a threshold voltage sensing driving method for the driving transistor DRT will be briefly described with reference to FIG. 4 .

4 is a diagram illustrating a threshold voltage sensing driving method of a driving transistor in an organic light emitting display device according to the present embodiments.

Referring to FIG. 4 , when the driving transistor DRT is driven for sensing the threshold voltage, the first node N1 and the second node N2 of the driving transistor DRT drive the reference voltage Vref and the threshold voltage sensing, respectively. It is initialized with the data voltage (Vdata) for

Thereafter, the first switch SW1 is turned off, and the first node N1 of the driving transistor DRT floats.

Accordingly, the voltage of the first node N1 of the driving transistor DRT rises.

When the voltage of the first node N1 of the driving transistor DRT rises for a predetermined time, the range of the rise gradually decreases and becomes saturated.

The saturated voltage of the first node N1 of the driving transistor DRT may correspond to a difference between the data voltage Vdata and the threshold voltage Vth or a difference between the data voltage Vdata and the threshold voltage deviation ΔVth. .

When the voltage of the first node N1 of the driving transistor DRT is saturated, the second switch SW2 of the sensing unit 310 is turned on and connected to the reference voltage line RVL.

Accordingly, the sensing unit 310 senses the saturated voltage of the first node N1 of the driving transistor DRT.

The voltage Vsen sensed by the sensing unit 310 is a voltage obtained by subtracting the threshold voltage Vth from the data voltage Vdata (Vdata-Vth) or a voltage obtained by subtracting the threshold voltage deviation (ΔVth) from the data voltage (Vdata) ( Vdata-ΔVth).

Next, a mobility sensing driving method for the driving transistor DRT will be briefly described with reference to FIG. 5 .

Referring to FIG. 5 , when the mobility sensing is driven, the first node N1 and the second node N2 of the driving transistor DRT are connected to a reference voltage Vref and a data voltage Vdata for driving the mobility sensing. initialized

Thereafter, the first switch SW1 is turned off, and the first node N1 of the driving transistor DRT is floated.

Accordingly, the voltage of the first node N1 of the driving transistor DRT rises.

In this case, the rate of increase of the voltage of the first node N1 of the driving transistor DRT represents the current capability of the driving transistor DRT, that is, the mobility α.

Accordingly, the voltage at the first node N1 of the driving transistor DRT rises more rapidly as the driving transistor DRT has a higher current capability (mobility).

Here, the rate of increase of the voltage of the first node N1 of the driving transistor DRT is the voltage variation ΔV for a certain period of time and corresponds to the slope shown in FIG. 5 .

When a predetermined time elapses after the first node N1 of the driving transistor DRT is floated, the second switch SW2 of the sensing unit 310 is turned on and connected to the reference voltage line RVL.

At this time, the sensing unit 310 controls the increased voltage of the first node N1 of the driving transistor DRT, that is, the voltage of the first node N1 of the driving transistor DRT, in which the voltage is increased for a predetermined period of time. The voltage of the line capacitor Csen on the reference voltage line RVL, in which the voltage rises along with the rise, is sensed.

That is, the voltage Vsen corresponding to the current Ids flowing through the driving transistor DRT is stored in the line capacitor Csen, and the sensing unit 310 senses the voltage Vsen stored in the line capacitor Csen. is to do

At this time, the mobility α of the driving transistor DRT may be inversely proportional to the square of the data voltage Vdata and proportional to the line capacitance Csen and the sensing voltage Vsen, as shown in Equation 1 below.

Even through Equation 1 above, it can be seen that the higher the mobility α is, the higher the sensing voltage Vsen is sensed.

According to the threshold voltage or mobility sensing drive of the above-described method, the sensing unit 310 converts the sensed voltage Vsen into a sensed value corresponding to a digital value for threshold voltage sensing or mobility sensing, and converts the converted Sensing data including sensing values is generated and output.

Sensing data output from the sensing unit 310 may be stored in the memory 320 or provided to the compensating unit 330 .

The compensator 330 outputs the characteristic values (eg, threshold voltage, mobility) or the driving transistor DRT in a corresponding subpixel based on the sensing data stored in the memory 320 or provided by the sensing unit 310. A characteristic value change (eg, threshold voltage change, mobility change) of , and a characteristic value compensation process may be performed.

Here, the change in the characteristic value of the driving transistor DRT may mean a change in current sensing data based on previous sensing data or a change in current sensing data based on reference data for mobility sensing.

Here, by comparing characteristic values or changes in characteristic values between the driving transistors DRT, deviations in characteristic values between the driving transistors DRT can be grasped. When the change in the characteristic value of the driving transistor DRT means that the current sensing data is changed based on the reference data for mobility sensing, the variation in the characteristic value between the driving transistors DRT from the change in the characteristic value of the driving transistor DRT (that is, the sub-pixel luminance deviation).

The characteristic value compensation process may include a threshold voltage compensation process for compensating the threshold voltage of the driving transistor DRT and a mobility compensation process for compensating for the mobility of the driving transistor DRT.

The threshold voltage compensation process calculates a compensation value to compensate for the threshold voltage or threshold voltage deviation (threshold voltage change), stores the calculated compensation value in the memory 320, or converts the corresponding image data (Data) into the calculated compensation value. It may include processing to change the .

The mobility compensation process calculates a compensation value for compensating for mobility or mobility deviation (mobility change), stores the calculated compensation value in the memory 320, or converts the corresponding image data (Data) into the calculated compensation value. It may include processing to change the .

Referring to FIG. 3 , the compensator 330 changes image data (Data) through threshold voltage compensation processing or mobility compensation processing, and supplies the changed data to the corresponding source driver integrated circuit (SDIC) in the data driver 120. can do it

Accordingly, the corresponding source driver integrated circuit (SDIC) converts the changed data into data voltage through the digital-to-analog converter 340 and supplies it to the corresponding subpixel, so that the subpixel characteristic value compensation (threshold voltage compensation, mobility compensation) is actually It will be done.

As such sub-pixel characteristic value compensation is performed, the luminance deviation between sub-pixels is reduced or prevented, thereby improving image quality.

FIG. 6 is a diagram exemplarily illustrating the order of threshold voltage sensing and mobility sensing in the organic light emitting display device 100 according to the present embodiments, and FIG. 7 is the organic light emitting display device 100 according to the present embodiments. It is an exemplary timing diagram of threshold voltage sensing and mobility sensing in .

Referring to FIG. 6 , the organic light emitting display device 100 according to the present exemplary embodiments may perform sensing of the mobility of the driving transistor DRT after sensing the threshold voltage of the driving transistor DRT.

Below, it is assumed that sensing of the threshold voltage of the driving transistor DRT is performed before sensing the mobility of the driving transistor DRT.

Accordingly, before the mobility of the driving transistor DRT is sensed, a compensation value for the threshold voltage of the driving transistor DRT is calculated, and the threshold voltage compensation value is reflected in mobility sensing data.

Sensing the threshold voltage of the driving transistor DRT takes a relatively long time compared to sensing the mobility of the driving transistor DRT because the voltage saturation time of the first node N1 of the driving transistor DRT is required. .

Considering this point, for example, as shown in FIG. 7 , sensing of the threshold voltage of the driving transistor DRT may be performed after a power-off signal is generated according to a user input and the like, while the image is not driven.

The sensing of the mobility of the driving transistor DRT may be performed even after a power-off signal is generated, but may be performed even during image driving, considering that it takes a short time.

Accordingly, as shown in FIG. 7 , sensing of the mobility of the driving transistor DRT may be performed after the power-on signal is generated.

Also, as shown in FIG. 7 , mobility of the driving transistor DRT may be sensed for every blank time between active times based on the vertical synchronization signal Vsync.

For example, the mobility of the driving transistor DRT in one subpixel may be sensed during one blank time, and in some cases, the mobility of the driving transistor DRT in two or more subpixels may be sensed. this may proceed.

FIG. 8A shows the generation of mobility sensing data for mobility sensing driving and the mobility compensation value α_comp′ based on the mobility sensing value α_sen in the organic light emitting display device 100 according to the present embodiments. It is a diagram for explaining the calculation of

Referring to FIG. 8A , the controller 140 of the organic light emitting display device 100 according to the present embodiments generates mobility sensing data for mobility sensing driving in a mobility sensing section, and the data driver 120 provided by

The data driver 120 generates a data voltage Vdata′ for mobility sensing through digital-to-analog conversion of mobility sensing data. However, below, the data voltage for mobility sensing is described as Vdata', and the data voltage used to generate the data voltage Vdata' for mobility sensing is described as Vdata.

Referring to FIG. 8A, a process of generating mobility sensing data will be described in terms of a voltage expression method.

Data for mobility sensing is generated based on reference data for mobility sensing, a previously stored threshold voltage compensation value (Vth_comp), and a previously stored mobility compensation value (α_comp).

The mobility sensing data voltage (Vdata') obtained by converting the mobility sensing data into analog is the reference sensing data voltage (Vdata) corresponding to the mobility sensing reference data, the threshold voltage compensation value (Vth_comp), and the mobility compensation. It may be expressed as a value (α_comp) or the like. However, the threshold voltage compensation value (Vth_comp) and the mobility compensation value (α_comp) are expressed without distinction between a digital value and an analog value for convenience of description.

More specifically, the data voltage Vdata' for mobility sensing is expressed as in Equation 2 below.

In Equation 2, g' is a gain (Gain) multiplied by the data voltage (Vdata) for reference mobility sensing, and this gain g' is D corresponding to the coefficient for optimizing mobility compensation and (α_comp - 1 ) and adding 1 to it.

In the mobility sensing period, the mobility sensing data voltage Vdata′ expressed as described above is generated and supplied to the second node N2 of the driving transistor DRT in the subpixel where mobility is to be sensed. .

In the mobility sensing period, the sensing unit 310 senses the voltage of the first node N1 of the driving transistor DRT, the voltage of which is increased according to the current capability of the driving transistor DRT, through the line capacitor Csen. do.

The sensing unit 310 obtains the mobility sensing value α_sen through analog-to-digital conversion of the sensing voltage Vsen, and provides it to the controller 140 .

The controller 140 calculates a mobility compensation value α_comp′ for the driving transistor DRT in a corresponding subpixel based on the mobility sensing value α_sen.

More specifically, as shown in Equation 3 below, the controller 140 multiplies the difference between the mobility sensing value α_sen and the reference mobility sensing value α_ref by a predetermined coefficient (-r) to measure the mobility sensing deviation. Calculate (Δα).

As shown in Equation 4 below, the controller 140 divides the mobility sensing deviation Δα by a predetermined constant k (Δα/k) and the previously calculated and stored mobility compensation value (α_comp). In addition, a new mobility compensation value (α_comp') may be calculated.

The controller 140 updates the existing mobility compensation value α_comp stored in the memory 320 to the newly calculated mobility compensation value α_comp′.

8B illustrates compensating image data for displaying an image with a mobility compensation value α_comp′ calculated based on a mobility sensing value α_sen in the organic light emitting display device 100 according to the present embodiments. It is a drawing for

Referring to FIG. 8B , a process of generating image data will be described using a voltage expression method.

Referring to FIG. 8B , in a display period in which an image is displayed within an active time based on a vertical synchronization signal Vsync, a subpixel SP displays an image. To display an image, the controller 140 generates compensated image data based on image data input from the outside according to Equation 2, a pre-stored threshold voltage compensation value (Vth_comp), and a pre-stored mobility compensation value (α_comp). do. In other words, the controller 140 generates compensated image data by using Equation 2 in the same way as generating the data voltage Vdata' for mobility sensing.

In this case, the previously stored mobility compensation value α_comp is the mobility compensation value α_comp updated with the mobility compensation value α_comp′ calculated by Equation 4. Therefore, the compensated image data is affected by the updated mobility compensation value (α_comp), and the luminance of the image displayed in the display section is affected by the mobility compensation value (α_comp).

Applying the mobility sensing method described above, mobility compensation according to a change (increase or decrease) in mobility and how the mobility changes through such mobility compensation will be briefly reviewed with reference to FIG. 9 .

9 is a diagram illustrating mobility compensation through mobility sensing and mobility deviation reduction according to the mobility compensation in the organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 9 , in a first mobility sensing period for any one subpixel, at a time point when the voltage of the first node N1 of the driving transistor DRT rises for a certain period of time (time indicated by a dotted line), the sensing unit 310 ) senses the voltage of the first node N1 of the driving transistor DRT. At this time, the sensed voltage (Vsen) is different according to the mobility (α).

Based on the fact that the mobility α of the driving transistor DRT does not change, when the mobility α increases, the sensing voltage Vsen increases, and when the mobility α decreases (decreases), the sensing voltage Vsen increases. The voltage Vsen is lowered.

When the sensing voltage Vsen increases because the mobility α of the driving transistor DRT increases, the mobility compensation value α compensation value decreases.

When the sensing voltage Vsen is lowered due to the decrease in the mobility α of the driving transistor DRT, the compensation value for the mobility α is increased.

When the next second mobility is sensed for the same subpixel using the mobility compensation value adjusted and calculated as described above, the same sensing voltage Vsen may be sensed. That is, it can be seen that the mobility is also compensated.

10 is a graph showing a relationship between mobility sensing values according to mobility characteristics for all subpixels of the same color in an organic light emitting display panel and after mobility compensation in an organic light emitting display device 100 according to the present embodiments. is a diagram showing the relationship between mobility sensing values according to mobility characteristics. FIG. 11 is a diagram illustrating a relationship between luminance according to mobility characteristics when an image is displayed in a display section by applying the relationship between mobility sensing values according to mobility characteristics after mobility compensation of FIG. 10 . 12 is a graph showing a relationship between mobility sensing values according to a change in mobility characteristics and mobility compensation for all subpixels of the same color in an organic light emitting display panel in the organic light emitting display device 100 according to the present embodiments. Hereafter, it is a diagram showing the relationship between a mobility sensing value and luminance according to mobility characteristics.

Referring to FIG. 10 , in a first mobility sensing period (eg, an initial sensing period in which mobility is not compensated before product release), all subpixels of the same color in the organic light emitting display panel 110 (for example, , R, W, G, and B subpixels), the mobility sensing value according to the mobility characteristics of the driving transistor DRT included in the subpixels has a constant rate that increases linearly. At this time, in the initial sensing period, the driving transistor DRT included in all subpixels of the same color (for example, one subpixel among R, W, G, and B subpixels) of the organic light emitting display panel 110 moves. The degree characteristic may mean an initial distribution of mobility of the driving transistor DRT.

In other words, when the mobility characteristic of the driving transistor DRT increases, the sensing value of the mobility of the driving transistor DRT also increases linearly. At this time, the fact that the mobility sensing value according to the mobility characteristic of the driving transistor DRT has a certain rate at which it increases linearly means that the slope of the mobility sensing value according to the mobility characteristic of the driving transistor DRT has a specific size. means that

When the mobility characteristic of the driving transistor DRT is high (high α), the mobility compensation value (α compensation value) is less than 1 (α compensation value < 1). Conversely, when the mobility characteristic of the driving transistor DRT is low (low α), the mobility compensation value (α compensation value) is greater (α compensation value > 1).

At this time, the mobility compensation value calculated by applying the optimal coefficient D value (optimal D in FIGS. If the following second mobility is sensed for all subpixels of the same color in the organic light emitting display panel 110 in the second mobility sensing period (for example, an update sensing period using a mobility compensation value) using Mobility sensing values according to mobility characteristics of driving transistors DRT included in all subpixels of the same color in the organic light emitting display panel 110 have the same value. Having the same value means that the slope of the mobility sensing value according to the mobility characteristics of the driving transistor DRT is 0. In this case, that the slope is 0 may mean that the value is within a range that does not substantially affect when the mobility compensation value is calculated using the mobility sensing value (the same below).

Referring to FIG. 12 , the second mobility sensing (updated mobility sensing) is a method of correcting a mobility compensation value based on a sensed sensing value, and since a coefficient D is applied when sensing an updated mobility, the coefficient D is affected. If the coefficient D is an optimal value, the updated mobility sensing value is equally sensed and the mobility compensation value is not modified.

On the other hand, by applying a smaller coefficient D value (smaller D in FIGS. 10 and 12) than the optimal D value (optimal D in FIGS. 10 and 12), the data voltage Vdata' for mobility sensing is calculated by Equation 2. When the following second mobility is sensed for all subpixels of the same color in the organic light emitting display panel 110 in the second mobility sensing period using the calculated mobility compensation value, the organic light emitting display panel ( 110), the mobility sensing value according to the mobility characteristics of the driving transistor DRT included in all subpixels of the same color increases linearly.

Conversely, movement calculated by adjusting the data voltage (Vdata') for mobility sensing by Equation 2 by applying a coefficient D value (D large) larger than the optimal coefficient D value (D optimal in FIGS. 10 and 12) When the next second mobility is sensed for all subpixels of the same color in the organic light emitting display panel 110 in the second mobility sensing period using the degree compensation value, the same color in the organic light emitting display panel 110 is sensed. The mobility sensing value according to the mobility characteristics of the driving transistor DRT included in all subpixels of is linearly reduced.

In other words, when the coefficient D is small, mobility compensation is insufficient during mobility sensing, and mobility characteristics are weakly sensed in the mobility sensing value, resulting in a larger deviation in the mobility compensation value. If the coefficient D is large, mobility compensation is excessive during mobility sensing, and mobility characteristics are sensed inversely to the mobility sensing value, resulting in a small deviation in the mobility compensation value.

In this case, as shown in FIGS. 11 and 12, if the image data is compensated by applying the mobility compensation value obtained by applying the updated mobility sensing value to the display section, the luminance will be the same regardless of the mobility characteristics (in FIG. 12). optimal) can be obtained.

13 is a graph illustrating a relationship between a mobility sensing value according to a change in mobility characteristics and a result after mobility compensation for any one subpixel in an organic light emitting display panel in the organic light emitting display device 100 according to the present embodiments. It is a diagram showing the relationship between mobility sensing values according to mobility characteristics. FIG. 14 is a diagram illustrating a relationship between luminance according to mobility characteristics when an image is displayed in a display section by applying the relationship between mobility sensing values according to mobility characteristics after mobility compensation of FIG. 13 .

Referring to FIG. 13, according to a change in the mobility characteristics of a driving transistor DRT included in any one subpixel in an n-th mobility sensing period (for example, an update sensing period in which mobility is compensated at a specific point in time after product launch). The mobility sensing value has a constant rate that increases linearly. In this case, the change in the mobility characteristics of the driving transistor DRT included in any one sub-pixel in the organic light emitting display panel 110 in the update sensing period is a change in the mobility of the driving transistor DRT due to a change in temperature or the like. means smaller.

That is, when the mobility characteristic of the driving transistor DRT increases, the sensing value of the mobility of the driving transistor DRT also increases linearly.

When the mobility characteristic of the driving transistor DRT is high (high α), the mobility compensation value (α compensation value) is less than 1 (α compensation value < 1). Conversely, when the mobility characteristic of the driving transistor DRT is low (low α), the mobility compensation value (α compensation value) is greater (α compensation value > 1).

At this time, by applying the D value that optimizes the mobility compensation and adjusting the mobility sensing data voltage (Vdata') by Equation 2, using the mobility compensation value calculated, the n + 1 mobility sensing section (eg For example, when the next n+1 th mobility sensing is performed for any one subpixel in the organic light emitting display panel 110 in the update sensing period using the mobility compensation value calculated in the n th mobility sensing period, The same value (the slope of the mobility sensing value according to the mobility characteristics of the driving transistor DRT) 0) has

That is, when a mobility characteristic is changed due to a temperature change or the like, the mobility sensing value is changed, and the mobility compensation value is corrected with the mobility sensing value. Finally, the mobility compensation value is accurately corrected so that the same current flows through the driving transistor to the sensing line in the n+1 th mobility sensing period.

When the nth mobility is sensed, if the D value (varies for each product model, but generally the optimized D = 1) is optimized for the mobility deviation and the mobility compensation is performed when the n+1th mobility is sensed, the same current flows. values are sensed the same.

However, as shown in FIG. 14, when image data is compensated by applying a mobility compensation value obtained by applying an updated mobility sensing value to a display section, in reality, the luminance is not the same even if the current flowing during mobility sensing is the same. don't This is because the current may increase more than the increase in the mobility sensing value when the subpixel emits light in the display period due to the nonlinearity of the voltage-current characteristic of the driving transistor, the temperature characteristic of the organic light emitting diode, and the effect of the switching transistor. Similarly, when a subpixel emits light in the display period, the current may decrease more than the decrease in the mobility sensing value. Therefore, even if the mobility sensing values converge to the same value during the n+1th mobility sensing, the luminance may not converge in the display section.

15 is a graph illustrating a relationship between a mobility sensing value according to a change in a mobility characteristic for any one subpixel in an organic light emitting display panel in an organic light emitting display device 100 according to the present embodiments, and after mobility compensation. It is a diagram showing the relationship between a mobility sensing value and luminance according to mobility characteristics.

Referring to FIG. 15 , a mobility compensation value is modified in the same way for a change in mobility characteristics. The difference is that the luminance is not the same according to the change in the mobility characteristics despite the mobility compensation when using the optimum D, in which the mobility sensing values are the same.

In summary with reference to FIGS. 12 and 15 , if the coefficient D is optimized according to the initial distribution, the luminance deviation caused by the initial distribution can be equalized, but the effect on the luminance change caused by the mobility characteristic change is small. If the coefficient D is modified small in accordance with the change in mobility characteristics due to temperature change or the like, the initial luminance deviation is reversed. That is, the luminance of a pixel having a high mobility characteristic is lowered.

Since the initial dispersion and change of the mobility characteristics are different phenomena, the coefficient D applied to the organic light emitting display panel 110 is the same color even though the optimum D for improving the initial dispersion and change of the mobility characteristics is different. It is necessary to apply a gradation D that satisfies both conditions since there is only one gradation D for the sub-pixels R, G, B, and W.

Hereinafter, an organic light emitting display device to which an optimum D that can simultaneously improve initial distribution and change of mobility characteristics and a method for compensating for the same will be described.

16 is a graph showing a relationship between mobility sensing values according to a change in mobility characteristics and mobility compensation for all subpixels of the same color in the organic light emitting display panel in the organic light emitting display device 100 according to the present embodiments. Hereafter, it is a diagram showing the relationship between a mobility sensing value and luminance according to mobility characteristics.

Referring to FIG. 16 , the mobility sensing value according to the change in the mobility characteristics of the driving transistor DRT included in all subpixels of the same color in the n-th mobility sensing period has a constant rate of increasing linearly. In other words, when the mobility characteristic of the driving transistor DRT increases, the sensing value of the mobility of the driving transistor DRT also increases linearly.

The calculated n-th mobility compensation value is multiplied by a coefficient D for optimizing the mobility compensation, and based on the corrected n-th mobility compensation value, n+1-th mobility sensing data is generated. At this time, the mobility calculated by adjusting the data voltage Vdata' for mobility sensing by Equation 2 by applying a coefficient D value (small D in FIG. 16) smaller than the optimal coefficient D value (D optimal in FIG. 16). When the next n+1th mobility sensing is performed for all subpixels of the same color in the organic light emitting display panel 110 in the n+1th mobility sensing period using the compensation value, the organic light emitting display panel 110 Mobility sensing values according to the mobility characteristics of the driving transistor DRT included in all subpixels of the same color have a constant ratio. In this case, the n+1 th mobility sensing value sensed in the n+1 th mobility sensing section has a constant ratio that increases linearly according to mobility characteristics.

At this time, the coefficient D value for optimizing the mobility compensation of the data voltage (Vdata') for mobility sensing is the same ratio as the n+1th mobility sensing value sensed in the n+1th mobility sensing section according to the mobility characteristics. It has a value smaller than the coefficient D for optimizing the mobility compensation used to have (D optimal in FIG. 16).

In the n+1th mobility sensing period, an n+1th mobility compensation value (smaller D in FIG. 16 ) is calculated from the n+1th mobility sensing value.

Similarly, the next n+2th mobility sensing for all subpixels of the same color in the organic light emitting display panel 110 is performed in the n+2th mobility sensing period by using the n+1th mobility compensation value. In this way, the mobility sensing values according to the mobility characteristics of the driving transistor DRT included in all subpixels of the same color in the organic light emitting display panel 110 converge linearly.

Based on the calculated n+1th mobility compensation value, image data of a subpixel displaying an image is compensated and output to a display section. Sub-pixels have the same luminance (optimum) according to mobility characteristics in the display period.

Hereinafter, in the organic light emitting display device 100 according to the present embodiments, the relationship between the mobility sensing values according to the change in mobility characteristics for all subpixels of the same color in the organic light emitting display panel, and after mobility compensation The relationship between a mobility sensing value and luminance according to mobility characteristics will be described with reference to FIGS. 17A and 17B.

The sensing unit 310 senses the voltage of the first node of the driving transistor during the n-th mobility sensing period of the driving transistor to output an n-th mobility sensing value, and outputs an n+1-th mobility sensing period of the driving transistor. In this case, the voltage of the first node of the driving transistor is sensed to output an n+1 th mobility sensing value.

As shown in FIG. 17A, the controller 140 calculates an n-th mobility compensation value from the n-th mobility sensing value, and the n+1-th mobility sensing value sensed in the n+1-th mobility sensing section. Based on the calculated n-th mobility compensation value to have a constant ratio according to the mobility characteristics, n+1 mobility sensing data is generated and output to the n+1-th mobility sensing section of the driving transistor, and An n+1 th mobility compensation value is calculated from the +1 mobility sensing value. As described above, the fact that the n+1 th mobility sensing value sensed in the n+1 th mobility sensing period has a constant ratio according to the mobility characteristic means that the mobility sensing value according to the mobility characteristic of the driving transistor DRT. This means that the gradient of the mobility sensing value has a specific size.

As a result, the n+1 th mobility sensing value sensed in the n+1 th mobility sensing section has a constant ratio that increases linearly according to mobility characteristics. As an example, it has been described that the n+1 th mobility sensing value has a constant rate that increases linearly according to the mobility characteristics, but the n+1 th mobility sensing value has a constant rate that increases linearly according to the mobility characteristics. , but may have a constant rate that increases nonlinearly, for example, in a cubic function.

The controller 140 multiplies the calculated n-th mobility compensation value by a coefficient for optimizing mobility compensation, and generates n+1-th mobility sensing data based on the corrected n-th mobility compensation value. As an example, it has been described that the calculated n-th mobility compensation value is multiplied by a coefficient for optimizing mobility compensation to modify the n-th mobility compensation value to generate n+1-th mobility sensing data, but the present invention Not limited.

In Equation 5, g' is a gain (Gain) multiplied by the reference mobility sensing data voltage (Vdata), and this gain g' corresponds to D' corresponding to a coefficient smaller than the optimal coefficient D value and (α_comp - It can be calculated by multiplying by 1) and adding 1.

As shown in FIG. 17B , the controller 140 compensates the image data of the subpixel displaying the image based on the calculated n+1 th mobility compensation value and outputs the compensated image data to the data driver 120 in the display section. The data driver 120 outputs compensated image data to a corresponding subpixel. The corresponding sub-pixel emits luminance corresponding to the compensated image data. The subpixels have the same luminance (optimal in FIG. 16) according to mobility characteristics in the display period.

At this time, the controller 140 compares the previously stored target mobility sensing value (target in FIG. 16) having a predetermined ratio according to the mobility characteristics and the nth mobility sensing value, and if they do not match, the nth mobility sensing value is corrected. The n-th mobility compensation value is calculated, and n+1-th mobility sensing data Vdata' is generated based on the corrected n-th mobility compensation value. In other words, when the n+1th mobility sensing data (Vdata') is generated, the mobility compensation value is corrected and corrected by comparing the target mobility sensing value pre-stored in the memory 320 with the actually sensed mobility sensing value. Based on the obtained mobility compensation value, next mobility sensing may be performed. The controller 140 compares the pre-stored target mobility sensing value having a predetermined ratio according to the mobility characteristics with the n-th mobility sensing value, and if they match, the n-th mobility compensation value is obtained without modification from the n-th mobility sensing value. and, based on the n-th mobility compensation value, n+1-th mobility sensing data Vdata' is generated.

Also, according to the present embodiments, the organic light emitting display device 100 can suppress both the luminance deviation due to the initial mobility characteristic deviation and the luminance change due to the mobility characteristic change.

Meanwhile, below, the compensation method of the organic light emitting display device 100 according to the above-described embodiments will be briefly described again.

18 is a flowchart of a compensation method of the organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 18 , the compensation method of the organic light emitting display device 100 according to the present embodiments includes the steps of generating mobility sensing data for sensing the mobility of a driving transistor DRT in a subpixel SP. (S810), outputting the mobility sensing data to the data driver 120 (S820), and the mobility sensing result of the driving transistor (DRT) in the subpixel (SP) using the mobility sensing data Receiving a corresponding mobility sensing value α_sen (S830), calculating a mobility compensation value α_comp' based on the mobility sensing value α_sen, and using the calculated mobility compensation value α_comp'. Updating the mobility compensation value α_comp previously stored in the memory 320 (S840) and the like may be included.

In the step of generating mobility sensing data (S810), the mobility sensing value α_sen sensed in the mobility sensing section based on the previously calculated mobility compensation value moves to have a certain ratio according to the mobility characteristic. It also generates data for sensing (Vdata'). As described above, the mobility sensing value α_sen sensed in the mobility sensing section has a constant ratio that increases linearly according to mobility characteristics.

Meanwhile, in the step of generating mobility sensing data (S810), mobility sensing is performed based on the mobility compensation value corrected by multiplying the previously calculated mobility compensation value (α_comp) by a coefficient D for optimizing mobility compensation. data (Vdata') is generated. At this time, as described above, the coefficient D for optimizing the mobility compensation is a value smaller than the coefficient for optimizing the mobility compensation used so that the mobility sensing values sensed in the mobility sensing section have the same ratio according to the mobility characteristics. have

Meanwhile, according to the step of outputting the mobility sensing data to the data driver 120 (S820), in the step of calculating the mobility compensation value (α_comp') based on the mobility sensing value (α_sen) (S2150), the movement The mobility compensation value α_comp′ for the subpixel SP may be calculated based on the degree sensing value α_sen.

In addition, a step of compensating image data (data) of a subpixel displaying an image based on the calculated mobility compensation value (α_comp') and outputting the image data to a display section is further included. At this time, the sub-pixels have the same luminance according to the mobility characteristics in the display period.

Meanwhile, a step of comparing a pre-stored target mobility sensing value (target) having a predetermined ratio according to a mobility characteristic and a previously calculated mobility sensing value (α_sen) may be further included. In the step of generating mobility sensing data (S810), if the target mobility sensing value (target) and the previously calculated mobility sensing value (α_sen) do not match, from the previously calculated mobility sensing value (α_sen) A modified mobility compensation value α_comp' is calculated, and mobility sensing data is generated based on the modified mobility compensation value α_comp'.

Using the above compensation method, it is possible to suppress both the luminance deviation due to the initial mobility characteristic deviation and the luminance change due to the mobility characteristic change.

According to the present embodiments as described above, it is possible to provide an organic light emitting display device 100 capable of more accurate mobility compensation and a compensation method thereof.

In addition, according to the present embodiments, it is possible to provide an organic light emitting display device 100 capable of suppressing both the luminance deviation due to the initial mobility characteristic deviation and the luminance change due to the mobility characteristic change, and a compensation method therefor. can

In addition, according to the present embodiments, it is possible to provide an organic light emitting display device 100 capable of maintaining the same luminance of an image despite a change in mobility characteristics in a display period and a compensation method thereof.

The above description and accompanying drawings are only illustrative of the technical idea of the present invention, and those skilled in the art can combine the configuration within the range that does not deviate from the essential characteristics of the present invention. , various modifications and variations such as separation, substitution and alteration will be possible. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the following claims, and all technical ideas within the equivalent range should be construed as being included in 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: controller

Claims (12)

a display panel on which a plurality of data lines and a plurality of gate lines are disposed and a plurality of subpixels are disposed;
a data driver driving the plurality of data lines;
a gate driver driving the plurality of gate lines; and
a controller controlling the data driver and the gate driver;
Each subpixel,
An organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a storage capacitor electrically connected between a first node and a second node of the driving transistor,
A sensing unit configured to sense a voltage of a first node of the driving transistor in a mobility sensing period of the driving transistor and output a mobility sensing value in digital form with respect to the sensed voltage;
The sensing unit,
In an n-th mobility sensing period of the driving transistor, a voltage at a first node of the driving transistor is sensed to output an n-th mobility sensing value;
In an n+1th mobility sensing period of the driving transistor, a voltage at a first node of the driving transistor is sensed to output an n+1th mobility sensing value;
The controller,
An n-th mobility compensation value is calculated from the n-th mobility sensing value, and the n + 1-th mobility sensing value sensed in the n + 1-th mobility sensing period has a predetermined ratio according to mobility characteristics, Based on the calculated n-th mobility compensation value, n+1-th mobility sensing data is generated and output to the n+1-th mobility sensing section of the driving transistor, and the n+1-th mobility sensing data is the first Calculate the n + 1 mobility compensation value,
The organic light emitting display device of claim 1 , wherein the n+1 th mobility sensing value increases at the constant rate other than 0 according to distribution of mobilities of driving transistors included in the plurality of subpixels. According to claim 1,
The organic light emitting display device of claim 1 , wherein the n+1 th mobility sensing value sensed in the n+1 th mobility sensing period has a constant ratio that increases linearly according to mobility characteristics. According to claim 2,
The controller,
An organic light emitting display device that compensates for image data of the subpixel displaying an image based on the calculated n+1 th mobility compensation value and outputs it to a display section. According to claim 3,
The organic light emitting display device of claim 1 , wherein the subpixels have the same luminance according to mobility characteristics in the display period. According to claim 1,
The controller,
Generating the n+1th mobility sensing data based on the n-th mobility compensation value corrected by multiplying the calculated n-th mobility compensation value by a coefficient for optimizing mobility compensation;
The coefficient for optimizing the mobility compensation optimizes the mobility compensation used so that the n+1 th mobility sensing value sensed in the n+1 th mobility sensing period has the same ratio according to mobility characteristics. An organic light emitting display device having a value smaller than a coefficient for According to claim 1,
The controller,
A pre-stored target mobility sensing value having a predetermined ratio according to a mobility characteristic is compared with the n th mobility sensing value, and if they do not match, a corrected n th mobility compensation value is calculated from the n th mobility sensing value, An organic light emitting display device generating data for sensing the n+1 th mobility based on the corrected n th mobility compensation value. generating mobility sensing data for sensing mobility of a driving transistor in a subpixel;
outputting the mobility sensing data to a data driver;
receiving a mobility sensing value corresponding to a mobility sensing result of a driving transistor in the subpixel using the mobility sensing data;
Calculating a mobility compensation value based on the mobility sensing value; and
Updating a mobility compensation value previously stored in a memory with the calculated mobility compensation value;
In the step of generating the mobility sensing data, the mobility sensing data that is sensed in the mobility sensing section based on the previously calculated mobility compensation value has a predetermined ratio according to the mobility characteristic. generates,
The method of claim 1 , wherein the mobility sensing value sensed in the mobility sensing period increases at the constant rate other than 0 according to the distribution of mobility of driving transistors included in the plurality of subpixels. According to claim 7,
The compensation method of the organic light emitting display device, wherein the mobility sensing value sensed in the mobility sensing section has a constant ratio that increases linearly according to mobility characteristics. According to claim 8,
Compensating for the image data of the sub-pixel displaying an image based on the calculated mobility compensation value and outputting the compensated image data to a display section. According to claim 9,
The compensation method of the organic light emitting display device wherein the subpixels have the same luminance according to mobility characteristics in the display period. According to claim 7,
In the step of generating data for the mobility sensing,
Generating the mobility sensing data based on the mobility compensation value modified by multiplying the previously calculated mobility compensation value by a coefficient for optimizing mobility compensation;
The coefficient for optimizing the mobility compensation has a smaller value than the coefficient for optimizing the mobility compensation used so that the mobility sensing values sensed in the mobility sensing section have the same ratio according to the mobility characteristics. Compensation method of organic light emitting display device. According to claim 7,
Further comprising the step of comparing the previously calculated mobility sensing value with a pre-stored target mobility sensing value having a predetermined ratio according to the mobility characteristic,
In the step of generating data for the mobility sensing,
If the target mobility sensing value and the previously calculated mobility sensing value do not match, a modified mobility compensation value is calculated from the previously calculated mobility sensing value, and the mobility compensation value is calculated based on the modified mobility compensation value. Compensation method of organic light emitting display device generating data for sensing.

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