KR102461389B1 - Organic Light Emitting Display Device And Driving Method Of The Same - Google Patents

Abstract

The present invention relates to an organic light emitting display device in which a time required for update compensation can be shortened while satisfying compensation accuracy by using a sequential sensing method for each color and a simultaneous sensing method for each unit pixel in parallel.
The organic light emitting display device according to the present invention senses electrical characteristics of driving TFTs for all sub-pixels of a display panel according to a color-by-color sequential sensing method, outputs a first sensed value, and uses a simultaneous sensing method for each unit pixel. Accordingly, a sensing unit that senses a change in electrical characteristics of a driving TFT for all unit pixels provided in the display panel and outputs a second sensed value, and a memory based on a difference between the first sensed value and the reference sensed value and a compensation parameter updater configured to update a stored compensation parameter and update the compensation parameter based on a difference between the second sensed value and the reference sensed value.

Description

Organic Light Emitting Display Device And Driving Method Of The Same

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device capable of compensating for variations in electrical characteristics of a driving TFT, and a driving method thereof.

The active matrix type organic light emitting diode display includes an organic light emitting diode (hereinafter, referred to as "OLED") that emits light by itself, and has advantages of fast response speed, luminous efficiency, luminance and viewing angle.

OLED, which is a self-luminous device, includes an anode electrode and a cathode electrode, and an organic compound layer (HIL, HTL, EML, ETL, EIL) formed therebetween. The organic compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and an electron injection layer (Electron Injection layer, EIL). When a driving voltage is applied to the anode and cathode electrodes, holes passing through the hole transport layer (HTL) and electrons passing through the electron transport layer (ETL) are moved to the light emitting layer (EML) to form excitons, and as a result, the light emitting layer (EML) is produces visible light.

The organic light emitting display device arranges pixels including OLEDs in a matrix form and adjusts the luminance of the pixels according to the gray level of video data. Each of the pixels includes a driving element that controls a driving current flowing through the OLED according to a voltage applied between the gate electrode and the source electrode, that is, a driving thin film transistor (TFT). The electric characteristics of the driving TFT change with temperature or deterioration. If the electrical characteristics of the driving TFT are different for each pixel, the luminance between the pixels for the same video data is different, so it is difficult to realize a desired image.

An external compensation technique is known to compensate for changes in electrical characteristics for a driving TFT. The external compensation technique senses the electrical characteristics of the driving TFT and modulates digital video data based on the sensing result.

1 shows a conventional first real-time compensation process (hereinafter, CSM compensation process) for compensating for a change in electrical characteristics of a driving TFT. Referring to FIG. 1 , in the conventional CSM compensation process, a sensing operation is performed in a vertical blank period VB excluding an image display period DP among one image frame. In the conventional CSM compensation process, one color belonging to one display line is sensed for every one image frame by using a vertical blank period (VB). In this method, sub-pixels belonging to one unit pixel are individually sensed in units of color. Hereinafter, such a sensing method is referred to as a “sequential sensing method for each color”. The CSM compensation process sequentially or non-sequentially (or randomly) senses all electrical characteristics of the driving TFTs of all sub-pixels positioned on 2160 display lines on the basis of Ultra High Definition (UHD) resolution, and then drives A compensation parameter for compensating for a change in the electrical characteristics of the TFT is simultaneously updated for all sub-pixels.

2 shows a sequential sensing method for each color applied to the conventional CSM compensation process. In Fig. 2, “D-TFT” denotes a driving TFT.

As shown in FIG. 2 , when each unit pixel UPXL consists of a red sub-pixel PR, a green sub-pixel PG, a blue sub-pixel PB, and a white sub-pixel PW, the sequential sensing method for each color is 1 A total of 4 sensing operations are required to sense the display line. In the color-by-color sequential sensing method, the red sub-pixels PR positioned on the first display line are simultaneously sensed during the first sensing, and the green sub-pixels PG positioned on the first display line are simultaneously sensed during the second sensing. In the third sensing, the blue sub-pixels PB positioned on the first display line are simultaneously sensed, and during the fourth sensing, the white sub-pixels PW positioned on the first display line are simultaneously sensed. In this sequential sensing method for each color, since a total of four sensing operations are required to sense one display line, the time it takes to update the compensation parameters of all sub-pixels of the display panel is inevitably long.

According to the sequential sensing method for each color, the time required for one-time update compensation for all sub-pixels is 72 seconds based on UHD resolution as shown in FIG. 3 requires 12 minutes of compensation time. The time required for update compensation increases as the area of the display panel increases and the resolution increases. In an organic light emitting diode display having a large area and high resolution, a new method for reducing the time required for update compensation while satisfying compensation accuracy to some extent is required.

Accordingly, it is an object of the present invention to provide an organic light emitting display device capable of reducing the time required for update compensation while satisfying compensation accuracy by using a sequential sensing method for each color and a simultaneous sensing method for each unit pixel in parallel, and a method for driving the same is to do

In order to achieve the above object, an organic light emitting display device according to the present invention generates a hybrid sensing control signal, and sequentially senses sub-pixels belonging to one unit pixel and sharing one sensing line in units of color in a color-by-color sequential sensing method; , a sensing control unit controlling a simultaneous sensing method for each unit pixel for simultaneously sensing at least some of the sub-pixels belonging to the one unit pixel, and driving all sub-pixels provided in the display panel according to the sequential sensing method for each color A first sensed value is output by sensing the electrical characteristics of the TFT, and a second sensing value is output by sensing the electrical characteristics of the driving TFT for all unit pixels provided in the display panel according to the simultaneous sensing method for each unit pixel. a sensing unit, a memory for respectively storing a reference sensing value and a compensation parameter for each sub-pixel, the difference between the first sensed value and the reference sensed value, and the difference between the second sensed value and the reference sensed value and a compensation parameter updater configured to update the compensation parameter based on the compensation parameter.

After outputting the second sensing value, the sensing unit senses the electrical characteristics of the driving TFTs for all unit pixels included in the display panel at least once more at least one more time according to the simultaneous sensing method for each unit pixel to perform a third The sensed value is output, and the compensation parameter updater further updates the compensation parameter based on a difference between the third sensed value and the reference sensed value.

After outputting the third sensed value, the sensing unit senses the electrical characteristics of the driving TFTs for all sub-pixels of the display panel once more according to the sequential sensing method for each color to obtain a fourth sensed value. output, and the compensation parameter update unit further updates the compensation parameter based on a difference between the fourth sensed value and the reference sensed value.

The compensation parameter updater sets a compensation rate for each color in advance, and applies the compensation ratio for each color when updating the compensation parameter.

The organic light emitting display device according to the present invention is updated and compensated through the compensation parameter and generates on-level sensing data for turning on the driving TFT and off-level sensing data for turning off the driving TFT. It further includes a data compensator supplied to the sensing unit.

In addition, in the method of driving an organic light emitting display device according to the present invention, a first sensing value is obtained by sensing electrical characteristics of a driving TFT for all sub-pixels provided in a display panel according to a sequential sensing method for each color, and the first sensing value is obtained. 1 updating a compensation parameter stored in a memory based on a difference between a sensing value and a preset reference sensing value; obtaining a second sensed value by sensing A method of sequentially sensing sub-pixels sharing a sensing line in units of color is shown, and the simultaneous sensing method for each unit pixel simultaneously senses at least some of the sub-pixels belonging to one unit pixel.

The present invention can reduce the time required for update compensation while satisfying the accuracy of compensation by using the sequential sensing method for each color and the simultaneous sensing method for each unit pixel in parallel. In particular, the present invention sequentially updates the compensation parameters stored in the memory to a desired target value through a plurality of compensation processes, but during the first compensation, the CSM compensation process according to the sequential sensing method for each color is performed to satisfy the compensation accuracy. In the case of the remaining compensation, the time required for compensation can be reduced by performing a USM compensation process according to the simultaneous sensing method for each unit pixel.

1 to 3 are diagrams for explaining a conventional CSM compensation process in which a sequential sensing method for each color is applied to compensate for a change in electrical characteristics of a driving TFT.
4 is a view showing an organic light emitting display device according to an embodiment of the present invention.
5 is a diagram illustrating an example of a configuration of a source driver IC including a sensing unit and a pixel array;
6 is a diagram showing an example of a configuration of sub-pixels constituting a pixel array;
7 and 8 are diagrams illustrating a configuration example of the sensing unit shown in FIG. 5 .
9 is a view showing the configuration of the present invention capable of implementing a hybrid sensing method by using a sequential sensing method for each color and a simultaneous sensing method for each unit pixel in parallel;
10 is a diagram showing an example of a sequential sensing method for each color for implementing a CSM compensation process.
11 is a diagram illustrating an example of a simultaneous sensing method for each unit pixel for implementing a USM compensation process.
12 and 13 are diagrams showing examples of compensation technology of the present invention to which a hybrid sensing method is applied.
14 is a view showing a comparison of the time required for update compensation of the present invention and the prior art.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. 4 to 14 .

4 shows an organic light emitting display device according to an embodiment of the present invention. 5 shows a configuration example of a source driver IC including a current sensing unit and a pixel array. 6 shows a configuration example of pixels constituting a pixel array. And, FIGS. 7 and 8 show a configuration example of the sensing unit shown in FIG. 5 .

4 to 8 , an organic light emitting diode display according to an embodiment of the present invention may include a display panel 10 , a timing controller 11 , a data driving circuit 12 , and a gate driving circuit 13 . have.

In the display panel 10 , a plurality of data lines and sensing lines 14A and 14B and a plurality of gate lines 15 cross each other, and sub-pixels P are arranged in a matrix form in each cross area. Make up a pixel array. The gate lines 15 include a plurality of first gate lines 15A to which the scan control signal SCAN is supplied, and a plurality of second gate lines 15B to which the sensing control signal SEN is supplied. can do. However, although not shown in the drawings, when the scan control signal SCAN and the sensing control signal SEN are unified, the first and second gate lines 15A and 15B may be replaced with one gate line.

Each sub-pixel P is disposed on any one of the data lines 14A, on any one of the sensing lines 14B, on any one of the first gate lines 15A, and on the second gate lines 15B. ) can be connected to any one of the The sub-pixels P constituting the pixel array include a red sub-pixel for displaying red, a green sub-pixel for displaying green, a blue sub-pixel for displaying blue, and a white sub-pixel for displaying white. do. Four sub-pixels including a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel may constitute one unit pixel UPXL. However, the configuration of the unit pixel UPXL is not limited thereto. Four sub-pixels P belonging to the same unit pixel UPXL may be commonly connected to one sensing line 14B. In other words, a plurality of sub-pixels P belonging to the same unit pixel UPXL may share one sensing line 14B. However, although not shown in the drawings, a plurality of sub-pixels P constituting the same unit pixel UPXL may be independently connected to different sensing lines. Each of the sub-pixels P receives a high potential driving voltage EVDD and a low potential driving voltage EVSS from a power generator (not shown).

The sub-pixel P of the present invention may include an OLED, a driving TFT DT, a storage capacitor Cst, a first switch TFT ST1, and a second switch TFT ST2. The TFTs may be implemented as a P type, an N type, or a hybrid type in which a P type and an N type are mixed. In addition, the semiconductor layer of the TFT may include amorphous silicon, polysilicon, or oxide.

The OLED includes an anode electrode connected to the source node Ns, a cathode electrode connected to the input terminal of the low potential driving voltage EVSS, and an organic compound layer positioned between the anode electrode and the cathode electrode. The organic compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and an electron injection layer (Electron Injection layer, EIL) may be included.

The driving TFT DT controls the magnitude of the source-drain current (hereinafter, referred to as Ids) of the driving TFT DT input to the OLED according to the gate-source voltage (hereinafter, referred to as Vgs). The driving TFT DT has a gate electrode connected to the gate node Ng, a drain electrode connected to the input terminal of the high potential driving voltage EVDD, and a source electrode connected to the source node Ns. The storage capacitor Cst is connected between the gate node Ng and the source node Ns to maintain the Vgs of the driving TFT DT for a certain period of time. The first switch TFT ST1 switches an electrical connection between the data line 14A and the gate node Ng according to the scan control signal SCAN. The first switch TFT ST1 includes a gate electrode connected to the first gate line 15A, a drain electrode connected to the data line 14A, and a source electrode connected to the gate node Ng. The second switch TFT ST2 switches an electrical connection between the source node Ns and the sensing line 14B according to the sensing control signal SEN. The second switch TFT ST2 includes a gate electrode connected to the second gate line 15B, a drain electrode connected to the sensing line 14B, and a source electrode connected to the source node Ns.

The organic light emitting diode display of the present invention having such a pixel array employs an external compensation technology. The external compensation technology senses the electrical characteristics of the driving TFT DT and corrects the input video data RGB according to the sensed value. The electrical characteristics of the driving TFT mean the threshold voltage of the driving TFT and electron mobility of the driving TFT.

The organic light emitting display device of the present invention performs an image display operation and an external compensation operation. The external compensation operation may be performed in the vertical blanking period during the image display operation, in the power-on sequence period before the image display starts, or in the power-off sequence period after the image display is finished. The vertical blank period is a period in which image data is not written, and is arranged between vertical active periods in which image data for one frame is written. The power-on sequence period refers to a period from when the driving power is turned on until an image is displayed. The power-off sequence period means a period from when the image display is finished until the driving power is turned off.

The timing controller 11 operates the data driving circuit 12 based on timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a dot clock signal DCLK, and a data enable signal DE. A data control signal DDC for controlling timing and a gate control signal GDC for controlling an operation timing of the gate driving circuit 13 are generated. The timing controller 11 temporally separates a period in which image display is performed and a period in which external compensation is performed, and control signals (DDC, GDC) for image display and control signals (DDC, GDC) for external compensation can be created differently.

The gate control signal GDC includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal (Gate Output Enable, GOE), and the like. The gate start pulse GSP is applied to the gate stage that generates the first scan signal to control the gate stage so that the first scan signal is generated. The gate shift clock GSC is a clock signal commonly input to the gate stages and is a clock signal for shifting the gate start pulse GSP. The gate output enable signal GOE is a masking signal that controls outputs of the gate stages.

The data control signal DDC includes a source start pulse (SSP), a source sampling clock (SSC), and a source output enable signal (SOE). The source start pulse SSP controls the data sampling start timing of the data driving circuit 12 . The source sampling clock SSC is a clock signal that controls the sampling timing of data in each of the source drive ICs based on a rising or falling edge. The source output enable signal SOE controls the output timing of the data driving circuit 12 .

The timing controller 11 may implement a hybrid sensing method by further generating a hybrid sensing control signal in the operation period for external compensation and controlling the sequential sensing method for each color and the simultaneous sensing method for each unit pixel in parallel. The timing controller 11 corrects the compensation parameter stored in the memory 16 based on the digital sensing value SD according to the hybrid sensing method, and then compensates the input digital video data RGB through the compensation parameter to generate pixels. It is possible to compensate for variations in the electrical characteristics of the inter-drive TFT. The timing controller 11 may transmit the compensated digital video data RGB to the data driving circuit 12 in an operation period for displaying an image. Also, the timing controller 11 may transmit, to the data driving circuit 12 , the on-level sensing data that is updated and compensated through the compensation parameter in the operation period for external compensation. Also, the timing controller 11 may transmit off-level sensing data to the data driving circuit 12 in an operation period for external compensation. Here, both the on-level sensing data and the off-level sensing data are for hybrid sensing.

The data driving circuit 12 includes at least one source driver integrated circuit (IC) (SDIC). The source driver IC (SDIC) includes a latch array (not shown), a plurality of digital-analog converters 121 (hereinafter referred to as DAC) connected to each data line 14A, and each sensing line 14B through a sensing channel. ) and a plurality of sensing units 122 connected to each other.

The latch array latches digital video data input from the timing controller 11 based on the data control signal DDC and supplies it to the DAC. The DAC may convert digital video data RGB input from the timing controller 11 into an image display data voltage and supply it to the data lines 14A during an image display operation. During an external compensation operation, the DAC generates on-level sensing data as an on-level sensing data voltage and supplies it to the data lines 14A, and generates off-level sensing data as an off-level sensing data voltage. Thus, it can be supplied to the data lines 14A.

The sensing unit 122 supplies the initialization voltages Vref and Vpre to the sensing line 14B based on the data control signal DDC, or an analog sensing value (electrical of the driving TFT) input through the sensing line 14B. characteristic value) can be sampled and supplied to an analog-to-digital converter (ADC). The sensing unit 122 may be implemented as a voltage sensing type as shown in FIG. 7 or as a current sensing type as shown in FIG. 8 . Among them, the current sensing type using a current integrator (CI) is advantageous in relatively reducing the sensing time because it enables low current and high speed sensing.

The voltage sensing type sensing unit 122 of FIG. 7 senses the voltage stored in the line capacitor LCa of the sensing line 14B in response to Ids of the driving TFT DT, and includes an initialization switch SW1, a sampling switch ( SW2), and a sample and hold unit S/H. The initialization switch SW1 switches an electrical connection between the input terminal of the initialization voltage Vref and the sensing line 14B according to the initialization control signal PRE. The sampling switch SW2 switches an electrical connection between the sensing line 14B and the sample and hold unit S/H according to the sampling control signal SAM. When the source node voltage of the driving TFT changes according to the Ids of the driving TFT DT, the sample-and-hold unit S/H generates a line capacitor ( After sampling and holding the source node voltage of the driving TFT (DT) stored in the LCa) as an analog sensing value, it is transferred to the ADC.

The current sensing type sensing unit 122 of FIG. 8 directly senses the Ids of the driving TFT transmitted through the sensing line 14B, and may include a current integrator CI and a sample & hold unit SH. The current integrator CI integrates current information flowing in through the sensing line 14B to generate an analog sensing value Vsen. The current integrator (CI) is an amplifier (AMP) including an inverting input terminal (-) receiving the Ids of the driving TFT from the sensing line 14B, a non-inverting input terminal (+) receiving an initialization voltage (Vpre), and an output terminal ), an integrating capacitor Cfb connected between the inverting input terminal (-) and the output terminal of the amplifier AMP, and a reset switch RST connected to both ends of the integrating capacitor Cfb. The current integrator (CI) is connected to the ADC through the sample & hold part (SH). The sample & hold unit SH samples the analog sensed value (Vsen) output from the amplifier (AMP) and stores the sampling switch (SAM) in the sampling capacitor (Cs), and the sensed value (Vsen) stored in the sampling capacitor (Cs). It may include a holding switch (HOLD) for transferring to the ADC.

The gate driving circuit 13 generates a scan control signal SCAN for an image display operation and an external compensation operation based on the gate control signal GDC, and then supplies it to the first gate lines 15A. The gate driving circuit 13 generates a sensing control signal SEN for an image display operation and an external compensation operation based on the gate control signal GDC, and then supplies it to the second gate lines 15B. The gate driving circuit 13 may be directly formed on the non-display area of the display panel 10 .

The memory 16 stores a reference sensing value and a compensation parameter for each sub-pixel, respectively. The reference sensed value is a sensing result of all sub-pixels performed in the product shipping stage, and refers to an initial sensed value of all sub-pixels before deterioration. The reference sensed value serves as a reference for determining a change in electrical characteristics of the driving TFT DT. The compensation parameter is a value continuously updated by an external compensation operation. The compensation parameter includes a ? component for compensating for a change in threshold voltage of the driving TFT DT and an ? component for compensating for a change in electron mobility of the driving TFT DT.

9 shows the configuration of the present invention capable of implementing a hybrid sensing method by using a sequential sensing method for each color and a simultaneous sensing method for each unit pixel in parallel.

Referring to FIG. 9 , the present invention includes a sensing control unit 11A to implement a hybrid sensing method, sensing units 12 and 13 for performing a sensing operation according to the hybrid sensing method, and a sensing value according to the hybrid sensing method ( SD1 to SDk, k is a positive integer greater than or equal to 2), the compensation parameter update unit 11B for updating the compensation parameters (Φ,α), the reference sensing value (SD-REF) and the updated compensation parameters (Φ, a memory 16 for storing α). The present invention may further include a data compensator 11C to implement a hybrid sensing method.

The sensing control unit 11A generates a hybrid sensing control signal HSCON and sequentially senses sub-pixels belonging to one unit pixel UPXL and sharing one sensing line in units of color, in a color-by-color sequential sensing method, and one unit pixel It is possible to control a simultaneous sensing method for each unit pixel that simultaneously senses sub-pixels belonging to .

The sensing units 12 and 13 may include the data driving circuit 12 and the gate driving circuit 13 described above. The sensing units 12 and 13 sense electrical characteristics of the driving TFTs DT for all sub-pixels included in the display panel 10 according to a color-by-color sequential sensing method to compensate the first sensing value SD1 as a compensation parameter. The second sensing value SD2 is outputted to the update unit 11B, and the electrical characteristics of the driving TFTs DT for all unit pixels provided in the display panel 10 are sensed according to the simultaneous sensing method for each unit pixel. It can output to the compensation parameter updater 11B. In addition, after the sensing units 12 and 13 output the second sensing value SD2 , the driving TFT (DT) for all unit pixels provided in the display panel 10 according to the simultaneous sensing method for each unit pixel may be sensed at least once more and output the third sensed value SD3 to the compensation parameter updater 11B. Here, the first sensed value SD1 is to satisfy the accuracy of compensation to some extent, and the second and third sensed values SD2 and SD3 are to shorten the time required for update compensation.

Meanwhile, after the sensing units 12 and 13 output the third sensing value SD3 , the driving TFT DT for all sub-pixels included in the display panel 10 according to a color-by-color sequential sensing method is controlled by the sensing units 12 and 13 . By sensing the electrical characteristic once more and outputting the fourth sensed value SD4 to the compensation parameter updater 11B, the accuracy of compensation may be further increased.

The compensation parameter update unit 11B includes a reference sensing value SD-REF read-out from the first area 16A of the memory 16 and first sensing values input from the sensing units 12 and 13 . The compensation parameters Φ and α may be first updated based on the difference between SD1 and stored in the second area 16B of the memory 16 . Subsequently, the compensation parameter updater 11B reads out the reference sensing value SD-REF from the first area 16A of the memory 16 and the second inputted from the sensing units 12 and 13 . Based on the difference between the sensed values SD2 , the primary update compensation parameters Φ and α previously stored in the second region 16B of the memory 16 may be secondarily updated. Subsequently, the compensation parameter update unit 11B includes the reference sensing value SD-REF read-out from the first area 16A of the memory 16 and the third input from the sensing units 12 and 13 . Based on the difference between the sensed values SD3 , the secondary update compensation parameters Φ and α previously stored in the second region 16B of the memory 16 may be thirdly updated. Subsequently, the compensation parameter update unit 11B reads out the reference sensing value SD-REF from the first area 16A of the memory 16 and the fourth input from the sensing units 12 and 13 . Based on the difference between the sensed values SD4 , the third update compensation parameters Φ and α previously stored in the second area 16B of the memory 16 may be updated fourth.

Meanwhile, the second sensed value SD2 and the third sensed value SD3 are obtained in units of the unit pixel UPXL, respectively, and correspond to the average of the sensed values of the sub-pixels included in the unit pixel UPXL. . That is, the second sensing value SD2 obtained from the specific unit pixel UPXL corresponds to the average of the sensing values of the sub-pixels belonging to the unit pixel UPXL, and the third sensing value SD2 obtained from the specific unit pixel UPXL. The value SD3 corresponds to an average of sensing values of sub-pixels belonging to the unit pixel UPXL. Accordingly, the compensation parameter update unit 11B performs a pre-experimental test in order to ensure that the compensation parameters Φ,α are not updated secondarily or tertiarily in units of unit pixels UPXL, but are secondarily or tertiarily updated in units of sub-pixels. You can set the compensation rate for each color in advance. For example, when the compensation parameter update unit 11B sets the compensation ratio of the green sub-pixel to 1, the compensation ratio of the red sub-pixel is 1.4, the compensation ratio of the blue sub-pixel is 1.5, and the compensation ratio of the white sub-pixel is 1.4. can be set. The compensation rate for each color may be set differently according to the model and specification of the display panel. The compensation parameter update unit 11B applies the compensation rate for each color at the time of the second or third update of the compensation parameters (Φ,α) for all sub-pixels, so that the compensation according to the simultaneous sensing method for each unit pixel is performed. A decrease in accuracy can be prevented as much as possible.

The data compensator 11C has an on-level sensing data SDATA-ON capable of turning on the driving TFT DT and an off-level sensing data SDATA capable of turning off the driving TFT DT. -OFF) can be generated and supplied to the sensing units 12 and 13 . Here, the on-level sensing data SDATA-ON may be updated and compensated through the compensation parameters Φ,α. Among the compensation parameters (Φ,α), the Φ component may be added as an offset value to the on-level sensing data (SDATA-ON), and among the compensation parameters (Φ,α), the α component is the on-level sensing data (SDATA-ON). ON) can be multiplied by the gain value. Accordingly, the on-level sensing data SDATA-ON may be applied in different sizes to sub-pixels having different electrical characteristics of the driving TFT DT. When the on-level sensing data (SDATA-ON) is changed to the update compensation method, faster compensation is possible and the compensation accuracy is increased. However, the on-level sensing data SDATA-ON is not individually controlled in units of sub-pixels according to the update compensation method, but may be applied to all sub-pixels with the same value. On the other hand, the off-level sensing data SDATA-OFF is selected from among the one unit pixel UPXL so that the sequential sensing method for each color is smoothly implemented, that is, only one sub-pixel is selectively sensed in one unit pixel UPXL. As it is applied to the remaining non-sensing subpixels, there is no need to apply an update compensation scheme. Accordingly, the off-level sensing data SDATA-OFF may be applied to all non-sensing sub-pixels with the same value.

The on-level sensing data SDATA-ON is converted into an on-level sensing data voltage (VON in FIGS. 10 and 11 ) through the sensing units 12 and 13 and is applied to the sensing target sub-pixels. , the off-level sensing data (SDATA-OFF) is converted to an off-level sensing data voltage (VOFF in FIGS. 10 and 11 ) through the sensing units 12 and 13 and then applied to non-sensing target sub-pixels. do.

10 shows an example of a sequential sensing method for each color for implementing a CSM compensation process. 11 shows an example of a simultaneous sensing method for each unit pixel for implementing a USM compensation process. And, FIGS. 12 and 13 show examples of compensation technology of the present invention to which a hybrid sensing method is applied.

10 , when each unit pixel UPXL is composed of a red sub-pixel PR, a green sub-pixel PG, a blue sub-pixel PB, and a white sub-pixel PW, for implementing the CSM compensation process In the sequential sensing method for each color, a total of 4 sensing operations are required to sense one display line. In the sequential sensing method for each color, the on-level sensing data voltage VON is applied only to the red sub-pixels PR positioned on the first display line during the first sensing, and only the red sub-pixels PR are sensed at the same time. In the second sensing, an on-level sensing data voltage VON is applied only to the green sub-pixels PG belonging to one display line to simultaneously sense only the green sub-pixels PG, and the third time During sensing, the on-level sensing data voltage VON is applied only to the blue sub-pixels PB belonging to one display line to simultaneously sense only the blue sub-pixels PB, and for the fourth sensing, one display line The on-level sensing data voltage VON is applied only to the white sub-pixels PW belonging to the minute, and only the white sub-pixels PW are simultaneously sensed. This sequential sensing method for each color can individually sense all sub-pixels, so the sensing accuracy is high, but the sensing time is long.

11 , when each unit pixel UPXL consists of a red sub-pixel PR, a green sub-pixel PG, a blue sub-pixel PB, and a white sub-pixel PW, the second real-time compensation process (hereinafter , CSM compensation process) requires only one sensing operation in total to sense one display line. In the simultaneous sensing method for each unit pixel, an on-level sensing data voltage (VON) is applied to all sub-pixels (PR, PG, PB, PW) positioned on one display line during one-time sensing to apply one unit pixel (UPXL). ), the sub-pixels PR, PG, PB, and PW are simultaneously sensed. This simultaneous sensing method for each unit pixel simultaneously senses four sub-pixels (PR, PG, PB, PW) belonging to the same unit pixel (UPXL), so the sensing time is reduced to 1/4 compared to the sequential sensing method for each color. can be reduced

Meanwhile, the simultaneous sensing method for each unit pixel of the present invention simultaneously senses all of the sub-pixels belonging to the same unit pixel UPXL, as well as a plurality of sub-pixels (eg, two or three). Simultaneous sensing may be included. In this case, a total of two sensing operations may be required to sense one display line, and the time required for sensing may be reduced to 1/2 compared to the sequential sensing method for each color.

In the present invention, the CSM compensation process according to the sequential sensing method for each color and the USM compensation process according to the simultaneous sensing method for each unit pixel are performed in parallel in consideration of the accuracy of compensation and the compensation time.

According to the present invention, the compensation parameter stored in the memory may be converged to a desired target value through a plurality of (eg, 10) compensation processes as shown in FIGS. 12 and 13 . Here, the desired target value means a value capable of completely compensating for changes in electrical characteristics of the driving TFT. In particular, the present invention may perform the CSM compensation process during the first compensation in order to satisfy the accuracy of compensation as shown in FIGS. 12 and 13 , but is not limited thereto. During the first compensation, the USM compensation process may be performed first. However, if the CSM compensation process is performed first, the compensation parameter may quickly approach a desired target value.

According to the present invention, when the compensation parameter approaches a desired target value through the first CSM compensation process, the compensation parameter may be further corrected through the subsequent 9 USM compensation processes as shown in FIG. 12 . If 72 seconds are required to perform the CSM compensation process once based on UHD resolution, the USM compensation process can be performed only once in 18 seconds. Accordingly, in the case of FIG. 12 , the total time required for compensation is 3 minutes and 54 seconds, which means that the time required for update compensation is approximately 67.5 compared to the conventional CSM compensation process performed only 10 times (total time required for compensation is 12 minutes). % can be shortened.

According to the present invention, in order to increase the accuracy of compensation, the first compensation process and the last compensation process among the multiple compensation processes may be selected as the CSM compensation process, and a plurality of USM compensation processes may be inserted between the CSM compensation processes. For example, according to the present invention, as shown in FIG. 13 , the CSM compensation process may be performed during the first and tenth compensation, and the USM compensation process may be performed during the second to ninth compensation. In this case, when the compensation parameter approaches the desired target value through the first CSM compensation process, the compensation parameter is further corrected through the subsequent second to ninth USM compensation processes, followed by the 10th CSM compensation process Finally, the compensation parameter can be precisely calibrated. In the case of FIG. 13, the total time required for compensation is 288 seconds, which can reduce the time required for update compensation by approximately 60% compared to the conventional CSM compensation process performed only 10 times (total time required for compensation is 12 minutes). means there is

Meanwhile, although not shown in the drawings, some of the second to ninth USM compensation processes of FIGS. 12 and 13 may be replaced with the CSM compensation process in order to further increase the accuracy of compensation. The replacement number may be appropriately selected in consideration of the accuracy of compensation and compensation time.

14 shows a comparison of the time required for update compensation of the present invention and the prior art. In FIG. 14 , “TY1” is the voltage sensing type sensing unit of FIG. 7 and indicates a method of compensating for the threshold voltage change of the driving TFT, and “TY2” is the current sensing type sensing unit of FIG. A method of compensating for all changes in electron mobility is shown.

Referring to FIG. 14 , in the present invention, 5 CSM compensation processes and 5 USM compensation processes can be performed in parallel, and in this case, the total time required for update compensation is approximately equal to that of performing the conventional CSM compensation process 10 times. It can be shortened by 37.5%. In addition, in the present invention, 3 CSM compensation processes and 7 USM compensation processes can be performed in parallel, and in this case, the total time required for update compensation can be reduced by approximately 52.5% compared to the conventional CSM compensation process performed only 10 times. can In addition, the present invention can perform one CSM reward process and nine USM reward processes in parallel, and in this case, the total time required for update compensation can be reduced by approximately 67.5% compared to performing only the conventional CSM reward process 10 times. can

As described above, according to the present invention, the time required for update compensation can be reduced while satisfying the accuracy of compensation by using the sequential sensing method for each color and the simultaneous sensing method for each unit pixel in parallel. In particular, the present invention sequentially updates the compensation parameters stored in the memory to a desired target value through a plurality of compensation processes, but during the first compensation, the CSM compensation process according to the sequential sensing method for each color is performed to satisfy the compensation accuracy. In the case of the remaining compensation, the time required for compensation can be reduced by performing a USM compensation process according to the simultaneous sensing method for each unit pixel. The present invention selects the first compensation process and the last compensation process among multiple compensation processes as the CSM compensation process, and inserts multiple USM compensation processes between the CSM compensation processes, thereby reducing compensation time and improving compensation accuracy. can be raised further.

Those skilled in the art from the above description will be able to see that various changes and modifications can be made without departing from the technical spirit of the present invention. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

10: display panel 11: timing controller
12: data driving circuit 13: gate driving circuit
14A: data line 14B: sensing line
15: gate line 16: memory
11A: sensing control unit 11B: compensation parameter update unit
11C: data compensation unit 12,13: sensing unit

Claims (10)

A color-by-color sequential sensing method for generating a hybrid sensing control signal and sequentially sensing sub-pixels belonging to one unit pixel and sharing one sensing line in color units, and simultaneously sensing at least some of the sub-pixels belonging to the one unit pixel a sensing control unit for controlling a simultaneous sensing method for each unit pixel;
In the first sensing, the electric characteristics of the driving TFTs for all sub-pixels provided in the display panel are sequentially sensed according to the color-by-color sequential sensing method to output a first sensed value, followed by the first sensing. a sensing unit configured to simultaneously sense electrical characteristics of driving TFTs for all unit pixels of the display panel according to the simultaneous sensing method for each unit pixel and output a second sensing value during the second sensing;
a memory for storing a reference sensing value and a compensation parameter for each of the sub-pixels; and
and a compensation parameter updater configured to update the compensation parameter based on a difference between the first sensed value and the reference sensed value and a difference between the second sensed value and the reference sensed value. The method of claim 1,
At the third sensing time after outputting the second sensing value, the sensing unit measures the electrical characteristics of the driving TFTs for all unit pixels included in the display panel at least once according to the simultaneous sensing method for each unit pixel. Simultaneously, more sensing is performed to output a third sensed value,
The compensation parameter update unit additionally updates the compensation parameter based on a difference between the third sensed value and the reference sensed value. 3. The method of claim 2,
At the fourth sensing time after outputting the third sensing value, the sensing unit sequentially measures the electrical characteristics of the driving TFTs for all sub-pixels of the display panel according to the color-by-color sequential sensing method once more. and output a fourth sensed value,
The compensation parameter update unit additionally updates the compensation parameter based on a difference between the fourth sensed value and the reference sensed value. 3. The method of claim 1 or 2,
The compensation parameter update unit sets a compensation rate for each color in advance, and applies the compensation ratio for each color when the compensation parameter is updated. 2. The method of claim 1,
A data compensator that is updated and compensated through the compensation parameter, generates on-level sensing data capable of turning on the driving TFT and off-level sensing data capable of turning off the driving TFT, and supplies it to the sensing unit. Further comprising an organic light emitting display device. During the first sensing, a first sensing value is obtained by sequentially sensing the electrical characteristics of the driving TFTs for all sub-pixels provided in the display panel according to a sequential sensing method for each color, and the first sensing value and a preset value are obtained. updating a compensation parameter stored in a memory based on a difference between reference sensed values; and
In the second sensing following the first sensing, electrical characteristics of driving TFTs for all unit pixels provided in the display panel are simultaneously sensed according to a simultaneous sensing method for each unit pixel to obtain a second sensing value, updating the compensation parameter based on a difference between the second sensed value and the reference sensed value;
The sequential sensing method for each color indicates a method for sequentially sensing sub-pixels belonging to one unit pixel and sharing one sensing line in units of color, and the simultaneous sensing method for each unit pixel is at least among the sub-pixels belonging to the one unit pixel. A driving method of an organic light emitting display device representing a method of simultaneously sensing a portion. 7. The method of claim 6,
In the third sensing following the second sensing, the electrical characteristics of the driving TFTs for all unit pixels provided in the display panel are simultaneously sensed at least once more according to the simultaneous sensing method for each unit pixel, and the third sensing method is performed. The method of driving an organic light emitting display device further comprising: acquiring a sensed value and further updating the compensation parameter based on a difference between the third sensed value and the reference sensed value. 8. The method of claim 7,
In the fourth sensing following the third sensing, the electric characteristics of the driving TFTs for all sub-pixels included in the display panel are sequentially sensed once more according to the sequential sensing method for each color, and the fourth sensing value and further updating the compensation parameter based on a difference between the fourth sensed value and the reference sensed value. 8. The method of claim 6 or 7,
In the updating of the compensation parameter, a compensation ratio for each color is set in advance, and the compensation ratio for each color is applied when the compensation parameter is updated. 7. The method of claim 6,
In order to implement the sequential sensing method for each color and the simultaneous sensing method for each unit pixel,
The organic light emitting display device comprising the step of being updated and compensated through the compensation parameter and generating on-level sensing data capable of turning on the driving TFT and off-level sensing data capable of turning off the driving TFT. driving method.

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