KR102281009B1 - Orgainc emitting diode display device and method for driving the same - Google Patents

Abstract

The present invention relates to an OLED display device capable of optimizing mobility compensation using different mobility compensation coefficients in a display mode and a sensing mode, and a driving method thereof.
An OLED display device and a driving method thereof according to the present invention are characterized in that a sensing mobility compensation coefficient applied to data in the sensing mode is set to a different value from a display mobility compensation coefficient applied to data in the display mode. .

Description

Organic light emitting diode display device and driving method therefor {ORGAINC EMITTING DIODE DISPLAY DEVICE AND METHOD FOR DRIVING THE SAME}

The present invention relates to an organic light emitting diode (OLED) display device, in particular, an OLED display device capable of optimizing mobility compensation using different mobility compensation coefficients in a display mode and a sensing mode, and the same It's about how to drive.

Recently, as flat panel displays that display images using digital data, liquid crystal displays (LCDs) using liquid crystals, OLED displays using OLEDs, and electrophoretic displays (EPDs) using electrophoretic particles are used. ), etc., for example.

Among them, the OLED display device is a self-luminous device that emits light from an organic light emitting layer by recombination of electrons and holes, and is expected as a next-generation display device because of its high luminance, low driving voltage, and ultra-thin film.

Each of the plurality of pixels or sub-pixels constituting the OLED display device includes an OLED element composed of an organic light emitting layer between an anode and a cathode, and a pixel circuit independently driving the OLED element.

The pixel circuit includes a switching thin film transistor (TFT) that supplies a data voltage to charge a voltage corresponding to the data voltage in the storage capacitor, and controls the current according to the voltage charged in the storage capacitor to supply the OLED device. Including a driving TFT and the like, the OLED element generates light proportional to the current. The current supplied to the OLED element is affected by driving characteristics such as the threshold voltage (Vth) and mobility of the driving TFT.

However, the threshold voltage or mobility of the driving TFT has a difference for each sub-pixel due to various causes. For example, there is a difference in the initial threshold voltage and mobility of the driving TFT for each sub-pixel due to process variation, etc., and the difference occurs for each sub-pixel due to deterioration of the driving TFT that occurs over the lapse of driving time. For this reason, the current for each sub-pixel for the same data is non-uniform, resulting in a luminance non-uniformity problem. To solve this problem, the OLED display uses an external compensation method for compensating for data by sensing the driving characteristics of the driving TFT.

For example, the external compensation method senses the voltage (or current) representing the driving characteristics of each driving TFT, calculates compensation values for compensating for the threshold voltage and mobility of the driving TFT based on the sensed values, and stores them in a memory or After updating, the data to be supplied to each sub-pixel is compensated using the stored compensation value.

However, there is a problem in that the mobility deviation is overcompensated when the mobility compensation value for each driving TFT is applied to data. This is because the gate-source voltage (Vgs) of the driving TFT with respect to the data voltage for each gray level changes nonlinearly.

In order to solve this problem, the present applicant in Patent Document 1 below, the data transfer efficiency (Data Transfer Efficiency; hereinafter DTE) defined as the ratio of the input data voltage (Vdata) to the gate-source voltage (Vgs) of the driving TFT during light emission was calculated through a simulation program and applied as a mobility compensation coefficient to prevent overcompensation when compensating for mobility deviation, an apparatus and method for compensating for image quality of an OLED display device were proposed.

However, the mobility compensation coefficient (DTE) presented in Patent Document 1 below is optimized for image display and has a problem in that it does not fit into the sensing mode. This is because conditions for driving the driving TFT are different even when the same data voltage is used in the display mode and the sensing mode. Specifically, since the initialization voltage supplied to the source node of the driving TFT is different in the display mode and the sensing mode, the gate-source voltage (Vgs) of the driving TFT for the same data voltage is different in the display mode and the sensing mode. am.

Accordingly, when the conventional mobility compensation coefficient (DTE) optimized for image display is applied to the data voltage in the sensing mode, the mobility compensation is not optimized, and thus the accuracy of the mobility sensing value and the mobility compensation value using the same decreases. . Accordingly, there is a problem in that image quality deteriorates due to unevenness and the like due to mobility compensation with poor accuracy.

Patent Document 1: Unexamined Patent Publication No. 10-2014-0119980 (2014.10.13)

The present invention has been devised to solve the above-described problems, and the object of the present invention is to provide an OLED display device capable of optimizing mobility compensation using different mobility compensation coefficients in a display mode and a sensing mode, and the same. to provide a driving method.

Another object of the present invention is to provide an OLED display device capable of further optimizing mobility compensation by detecting and applying a mobility compensation coefficient for sensing optimized according to panel characteristics and a driving method thereof.

In order to solve the above problems, in an OLED display device and a driving method thereof according to an embodiment of the present invention, a mobility compensation coefficient for sensing applied to data in a sensing mode is a mobility compensation coefficient for display applied to data in a display mode. and is set to a different value.

The OLED display includes a display panel including a plurality of sub-pixels having different colors, compensation information for compensating for characteristics of each sub-pixel, and at least one of a mobility compensation coefficient for display and a mobility compensation coefficient for sensing. The stored memory and data to be supplied to each sub-pixel in display mode are compensated by applying compensation information and display mobility compensation coefficient, and in sensing mode, data is compensated and compensated by applying compensation information and sensing mobility compensation coefficient. and a data processing unit that senses characteristics of each sub-pixel using the obtained data and updates correction information by using a sensed value sensed from each sub-pixel.

The mobility compensation coefficient for sensing is stored in one of a memory and a register of the data processing unit.

The compensation information stored in the memory includes a mobility compensation value for compensating for the mobility characteristic of the driving TFT of each sub-pixel, a threshold voltage compensation value for compensating a threshold voltage of the driving TFT, and a reference value when updating the mobility compensation value. It includes a mobility reference value for each color used as The display mobility compensation coefficient is set according to voltage data for each color and each gradation. The sensing mobility compensation coefficient is set for each color according to at least one sensing data, or is set for each color according to the at least one sensing data for each panel.

When a voltage corresponding to the compensated data is supplied to the gate node of the driving TFT, initialization voltages applied to other nodes of the driving TFT are different from each other in the sensing mode and the display mode.

The data processing unit includes a compensation unit and a data driver. In the display mode, the compensator compensates data by applying a mobility compensation value, a display mobility compensation coefficient, and a threshold voltage compensation value, and supplies the compensated data to a corresponding sub-pixel through a data driver. In the sensing mode, the compensator compensates data by applying a mobility compensation value, a sensing mobility compensation coefficient, and a threshold voltage compensation value, supplies the compensated data to a corresponding sub-pixel through a data driver, and outputs the data from the corresponding sub-pixel The detected signal is sensed through the data driver to detect a mobility sensed value, and a mobility compensation value is updated using an error value between the mobility sensed value and the mobility reference value.

The data processing unit updates the mobility of each sub-pixel by applying an initial mobility sensing value of each sub-pixel, and any one of the mobility compensation coefficients, the mobility compensation value, and the threshold voltage compensation value. By using the sensing mobility compensation coefficient detection unit for detecting the sensing mobility compensation coefficient is further provided.

The mobility compensation coefficient detector for sensing applies any one of the mobility compensation coefficients in the sensing mode before shipment of the product, and the first slope of the first straight line representing the relationship between the updated mobility sensed value and the initial mobility sensed value , calculates a second inclination of a second straight line representing the relationship of the first inclination to the mobility compensation coefficient, and detects a mobility compensation coefficient at a point where the first inclination becomes “0” in the second straight line. and set as the mobility compensation coefficient for sensing.

The mobility compensation coefficient detector for sensing connects a first point having a mobility compensation coefficient of “0” and a first slope of “1” and a second point indicating any one of the mobility compensation coefficients and the calculated first slope. A second inclination is calculated from the relationship of the second straight line.

The compensator updates and senses the mobility of each sub-pixel for each color by applying a sensing mobility compensation coefficient, a mobility compensation value, and a threshold voltage compensation value in the sensing mode before product shipment, and the updated mobility sensing value for each color. This converging value is set as the mobility reference value for each color and stored in the memory.

The OLED display device and the method for driving the same according to the present invention can improve the accuracy of the sensing value and the compensation value by sensing the mobility characteristics of each sub-pixel by applying a compensation coefficient for sensing different from the compensation coefficient for display in the sensing mode. The picture quality can be improved.

In addition, the OLED display device and the method for driving the same according to the present invention calculate the compensation coefficient for sensing optimized for each panel, and thus apply the optimal compensation coefficient for sensing according to the characteristics of the panel as well as the data voltage for sensing to move each sub-pixel. Since the accuracy of the sensed value and the compensation value can be improved by sensing the degree characteristic, the image quality can be improved.

In addition, the OLED display device and the driving method thereof according to the present invention update the mobility compensation value through the update sensing to which the compensation coefficient optimized for sensing is applied, so that the temperature and light-sensitive mobility characteristics can be sensed and compensated at high speed. there is.

Accordingly, in the OLED display device and the driving method according to the present invention, the accuracy of the mobility compensation value is improved by applying the compensation coefficient for sensing optimized for each panel and improving the convergence characteristic of the sensing values with respect to the reference value (average value) during update sensing. It can be improved, so the picture quality can be improved.

1 is a graph illustrating, for example, a mobility compensation coefficient for voltage data applied to an OLED display device according to the prior art.
2 is a block diagram schematically illustrating an OLED display device according to an embodiment of the present invention.
FIG. 3 is an equivalent circuit diagram illustrating the R/W/B/G subpixel structure shown in FIG. 2 by way of example.
4 is a diagram illustrating an example of a real-time sensing period in an OLED display device according to an embodiment of the present invention.
FIG. 5 is a block diagram specifically illustrating an internal configuration of the image processing unit shown in FIG. 2 .
6 is a diagram illustrating a method of driving an OLED display in a sensing mode and a display mode in stages according to an embodiment of the present invention.
7 is a graph illustrating, for example, a mobility compensation coefficient for voltage data applied to a sensing mode in an OLED display device according to an embodiment of the present invention.
8 is a flowchart illustrating a method of detecting a mobility compensation coefficient for sensing in an OLED display device according to another embodiment of the present invention in stages.
9 is a graph illustrating a relationship between an initial mobility sensed value and an updated mobility sensed value according to a plurality of compensation coefficients.
10 is a graph illustrating a relationship between a first slope with respect to a mobility compensation coefficient.
11 is a block diagram illustrating an internal configuration of an image processing unit of an OLED display device according to another exemplary embodiment of the present invention.
12 is a view showing the convergence characteristic of the updated sensing value of the OLED display device according to the present invention compared with the conventional one.

Prior to the description of the embodiment of the present invention, a specific cause of the mobility compensation coefficient (DTE) optimized for image display in the OLED display device according to the prior art does not fit into the sensing mode will be first examined.

The current Ids of the driving TFT supplied to the OLED element in each sub-pixel may be defined by Equation 1 below.

<Equation 1>

Ids = α(Vgs - Vth) ²

Here, α is a proportional coefficient including the mobility of the driving TFT and the channel width (W)/length (L) component, Vgs is the gate-source voltage of the driving TFT, and Vth is the threshold voltage of the driving TFT. Since the threshold voltage (Vth) and mobility (α) of each driving TFT are different, the threshold voltage and mobility of each driving TFT are sensed, and the threshold voltage compensation value (Vth) and the mobility compensation value ( α_cmp) is calculated and stored.

The method of sensing the mobility (α) includes the initial sensing method of determining the mobility compensation value (α_cmp) by initially sensing the mobility (α) as it is, and the mobility (α_cmp) using the mobility compensation value (α_cmp) stored in real time. and an update sensing method of updating the mobility compensation value α_cmp by sensing the error of the mobility α after compensating for α).

For a uniform pixel current, the voltage data Vdata is compensated as in Equation 2 below using the stored threshold voltage compensation value Vth and the mobility compensation value α_cmp.

<Equation 2>

MVdata = g×Vdata+Vth

where g = DTE×(α_cmp-1)+1

As shown in Equation 2, the gain value g is calculated through a predetermined operation using the mobility compensation value α_cmp and the mobility compensation coefficient DTE, and then the gain value g is converted into voltage data Vdata. The voltage data Vdata is compensated by multiplying by and adding the threshold voltage compensation value Vth.

The mobility compensation coefficient DTE is multiplied by the mobility compensation value α_cmp in order to prevent overcompensation of the mobility. As shown in FIG. 1 , the mobility compensation coefficient DTE is variable according to the gray level, that is, the voltage data Vdata for each gray level. It is a Vdata function that does 1 shows the mobility compensation coefficient (DTE) set according to the voltage data (Vdata) of the B subpixel among red (hereinafter R), white (hereinafter W), green (hereinafter G), and blue (hereinafter B) subpixels. This is the graph shown as an example. As shown in FIG. 1 , the mobility compensation coefficient DTE for the voltage data Vdata for each gradation is calculated in advance for each color and stored in the memory in the form of a look-up table (hereinafter referred to as LUT).

When the voltage data MVdata compensated by Equation 2 is converted into an analog voltage and supplied to the driving TFT of the corresponding subpixel, the current Ids of the driving TFT may be expressed by Equation 3 below.

<Equation 3>

Ids = α×(MVdata-Voffset-Vth) ²

In Equation 3, Voffset denotes an offset component including an initialization voltage supplied to the source node of the driving TFT and a kickback voltage indicating an amount of change in the gate-source voltage (Vgs) by the parasitic capacitor of the driving TFT. Therefore, "MVdata-Voffset" means the driving voltage (Vgs) of the driving TFT.

In a display mode for displaying an image and a real-time sensing mode for updating and sensing the mobility compensation value (α_cmp), the OLED display device according to the prior art has a threshold voltage compensation value (Vth) stored in a memory and a mobility compensation value (α_cmp) , compensates the voltage data Vdata as in Equation 2 using the mobility compensation coefficient DTE, and drives the corresponding sub-pixel using the compensated voltage data MVdata.

In the sensing mode, when the data voltage MVdata is supplied to the gate node of the driving TFT, an initialization voltage different from that in the display mode is supplied to the source node of the driving TFT. For this reason, in the sensing mode and the display mode, even when the same voltage data MVdata is used, the offset component Voffset including the initialization voltage and the kickback voltage of the source node is different, so that the gate-source voltage Vgs of the driving TFT is will be different from each other.

The mobility compensation coefficient (DTE) is used by calculating the ratio of the voltage data (Vdata) to the gate-source voltage (Vgs) of the driving TFT. It is also a Vgs function that varies according to the gate-source voltage (Vgs). Therefore, even if the voltage data Vdata is the same, if the gate-source voltage Vgs of the driving TFT is different, the mobility compensation coefficient DTE must also be applied differently.

However, the OLED display device according to the prior art moves in the sensing mode by applying the mobility compensation coefficient (DTE) optimized for the display mode to the sensing mode as it is, even though the Vgs for the same Vdata are different in the sensing mode and the display mode. There is a problem in that the image quality is deteriorated due to the decrease in the accuracy of the degree compensation.

In order to solve the problems of the prior art, the OLED display device according to the present invention has a mobility compensation coefficient (DTE) different from the display mode in the sensing mode in consideration of the different Vgs for the same Vdata in the sensing mode and the display mode. Suggest ways to apply

Hereinafter, preferred embodiments of the present invention will be described.

2 is a block diagram schematically illustrating an OLED display device according to an embodiment of the present invention.

The OLED display shown in FIG. 2 includes a timing controller 10 including a control signal generating unit 100 and an image processing unit 200 , a memory M, a data driver 20 , a gate driver 30 , and a display. A panel 40 and the like are provided. Here, the image processing unit 200 and the data driver 20 may be expressed as a data processing unit.

The image processing unit 200 may be built into the timing controller 10 as shown in FIG. 2 and configured as a single IC, or may be configured as a separate IC separated from the timing controller 10 (not shown). In this case, the timing controller 10 ) may be connected between the image processing unit 200 and the data driver 20 . Hereinafter, a case in which the timing controller 10 includes the image processing unit 200 will be described as an example.

In the memory M, compensation information set according to the characteristics of each sub-pixel for a uniform current of each sub-pixel, that is, a threshold voltage compensation value Vth for compensating the threshold voltage of each driving TFT, and mobility of the driving TFT The mobility compensation value (α_cmp) for compensating for the deviation is stored in the form of LUT.

Compensation information (Vth, α_cmp) is preset based on a sensing value of sensing the threshold voltage and mobility of each driving TFT before shipment of the product and is stored in the memory M. After the product is shipped, the compensation information (Vth, α_cmp) stored in the memory M is updated by sensing the characteristics of each sub-pixel again through the sensing mode every desired driving time. At least one desired time including the boot time at power-on, the end time at power-off, and the blanking period of each frame, the sensing mode is executed to update the compensation information (Vth, α_cmp) stored in the memory M there is.

For example, since the mobility of each driving TFT is affected by external environmental conditions, such as temperature and light, it is sensed and stored in the memory M at at least one of the booting time and the blanking period of each frame during power-on. The mobility compensation value α_cmp may be updated. The threshold voltage of each driving TFT may be sensed at each end time during power-off, and the threshold voltage compensation value Vth stored in the memory M may be updated. The following sensing mode will be described using a real-time sensing mode for updating the mobility compensation value α_cmp as an example.

In addition, in the memory M, the display mobility compensation coefficient DTE1 used together with the mobility compensation value α_cmp when the voltage data is corrected in the display mode is preset for each color and each gradation (for each voltage data). is stored in the form of LUT, and an average value (α_avg) of the initially sensed mobility as a reference value used when updating the mobility compensation value (α_cmp) is preset for each color and stored. The LUT of the display mobility compensation coefficient DTE1 is stored in advance for each color by experimentally calculating the ratio of the voltage data Vdata to the gate-source voltage Vgs of the driving TFT in the display mode.

In particular, the mobility compensation coefficient DTE1 for display and the other mobility compensation coefficient DTE2 for sensing are set and stored in the memory M in advance. The sensing mobility compensation coefficient DTE2 is experimentally stored for each color by experimentally calculating the ratio of the sensing voltage data Vdata to the gate-source voltage Vgs of the driving TFT in the sensing mode. Alternatively, the mobility compensation coefficient DTE2 for sensing may be stored in a register built in the timing controller 10 rather than in the external memory M.

Since the sensing mode uses fixed voltage data for sensing (Vdata) for each panel, the mobility compensation coefficient for sensing (DTE2) is not in the same LUT form as the mobility compensation coefficient for display (DTE1), but fixed voltage data for sensing (Vdata). ) may be set as a fixed coefficient and stored, or may be set and stored as a fixed coefficient for voltage data Vdata for sensing for each color.

Table 1 below shows, for example, the mobility compensation coefficient DTE2 for sensing with respect to the voltage data Vdata set optimized for the sensing mode, and FIG. 3 is a graph showing Table 1 below.

Vdata DTE2 4V 1.043 5V 0.943 6V 0.865 7V 0.816 8V 0.766 9V 0.743 10V 0.723

In the sensing mode, since voltage data (Vdata) fixed for each panel is used, one sensing mobility compensation coefficient (DTE2) corresponding to the voltage data (Vdata) is stored and used in the memory (M) or an internal register. .

1 and 3, the display mobility compensation coefficient (DTE) shown in FIG. 1 has a characteristic of gradually increasing in the voltage data (Vdata) 4V to 10V section, while the sensing shown in FIG. It can be seen that the mobility compensation coefficient DTE2 has a characteristic of gradually decreasing as opposed to FIG. 1 in the range of 4V to 10V of the voltage data Vdata. Accordingly, the present invention sets the display mobility compensation coefficient DTE and the sensing mobility compensation coefficient DTE2 for the same voltage data Vdata differently according to the gate-source voltage Vgs of the driving TFT. Save.

In the timing controller 10 , the control signal generator 100 controls the driving timings of the data driver 20 and the gate driver 30 using a plurality of timing signals input to an external system (not shown), respectively. A control signal and a gate control signal are generated and output to the data driver 20 and the gate driver 30 . For example, the control signal generator 100 controls the driving timing of the data driver 20 using a plurality of timing signals such as a clock signal, a data enable signal, a horizontal synchronization signal, and a vertical synchronization signal from an external system. a plurality of data control signals including a source start pulse, a source shift clock, a source output enable signal, and the like, and a plurality of gates including a gate start pulse and a gate shift clock for controlling the driving timing of the gate driver 30 . It generates and outputs a control signal.

In the timing controller 10 , the image processing unit 200 compensates image data input from an external system using the compensation information Vth and α_cmp and the mobility compensation coefficients DTE1 and DTE2 of the memory M, and compensates the data is output to the data driver 20 . The image processing unit 200 updates the compensation information Vth and α_cmp of the memory M by processing the sensing information of each subpixel sensed through the data driver 20 according to a predetermined operation.

In particular, the image processing unit 200 uses the display mobility compensation coefficient DTE1 when compensating for data in the display mode, and compensating for the sensing mobility set differently from the display mobility compensation coefficient DTE1 when compensating for data in the sensing mode. The coefficient (DTE2) is used.

In addition, in order to reduce power consumption, the image processing unit 200 determines the peak luminance according to the image of each frame using the input image data, calculates the total current, and determines the high potential voltage according to the peak luminance and the total current. It is also supplied to the data driver 20 .

In addition, when R/G/B data is input as image data to an external system, the image processing unit 200 converts the R/G/B data into R/G/B/W data through a predetermined operation to convert the above-described image. available for processing.

The data driver 20 converts the data supplied from the timing controller 10 into an analog data signal by using the data control signal supplied from the timing controller 10 in the display mode and the sensing mode, and supplies it to the display panel 40 . do. The data driver 20 converts digital data into analog data voltages using a gamma voltage set from a built-in gamma voltage generator (not shown).

In addition, the data driver 20 converts the digital high potential voltage supplied from the current controller 210 of the timing controller 10 into an analog high potential voltage in the display mode and the sensing mode, or converts the digital high potential voltage into an analog high potential voltage according to the digital high potential voltage. The voltage is adjusted and supplied to the display panel 40 . The gamma voltage generator generates a gamma voltage set including a plurality of gamma voltages by dividing the analog high potential voltage through a resistor string.

Also, in the sensing mode, the data driver 20 converts a voltage (or current) sensed from each subpixel of the display panel 50 through a sensing line into a digital sensing value and supplies it to the timing controller 10 . Any one of a data line, a reference line, and a power line connected to each sub-pixel may be used as a sensing line for outputting a current including characteristics of each sub-pixel to the data driver 20 .

The data driver 20 is composed of at least one data drive IC and is mounted on a circuit film such as a tape carrier package (TCP), a chip on film (COF), a flexible print circuit (FPC), and the like, and a TAB on the display panel 40 . It may be attached using a tape automatic bonding method or may be mounted on a non-display area of the display panel 40 using a chip on glass (COG) method.

The gate driver 30 drives a plurality of gate lines of the display panel 40 using a gate control signal supplied from the timing controller 10 . The gate driver 30 supplies a scan pulse of a gate-on voltage in a corresponding scan period to each gate line using a gate control signal, and supplies a gate-off voltage in the remaining period. The gate driver 30 may receive a gate control signal directly from the timing controller 10 or may receive a gate control signal from the timing controller 10 via the data driver 20 .

The gate driver 30 is composed of at least one gate drive IC, is mounted on a circuit film such as TCP, COF, FPC, etc. and is attached to the display panel 40 in a TAB method or is not displayed on the display panel 40 in a COG method. It can be mounted on the area. In contrast, the gate driver 30 is formed in the non-display area of the TFT substrate together with the TFT array formed in the pixel array of the display panel 40 to form a gate in panel (GIP) type embedded in the display panel 40 . can be

The display panel 40 includes a matrix-type pixel array. Each pixel of the pixel array is comprised of R/W/B/G subpixels. Alternatively, each pixel may comprise R/G/B subpixels.

FIG. 4 is an equivalent circuit diagram illustrating the R/W/B/G sub-pixel structure shown in FIG. 2 by way of example.

The R/W/B/G sub-pixels are respectively connected to the data lines DL1 to DL4 , share a pair of gate lines GL1 and GL2 , and share a reference line RL. Alternatively, although not shown, the R/W/B/G sub-pixels may share one gate line or may be respectively connected to different reference lines. A pair of data lines DL1 and DL2 are arranged in parallel between the R/W subpixels, and the other pair of data lines DL3 and DL4 are arranged in parallel between the B/G subpixels.

One power supply line PL disposed on the left side of the R subpixel is commonly connected with the R/W subpixels, and another power supply line PL disposed on the right side of the G subpixel is commonly connected with the B/G subpixels. A high potential voltage (EVDD) is supplied.

Each of the R/W/B/G sub-pixels includes an OLED device, first and second switching TFTs ST1 and ST2, a driving TFT DT, and a storage capacitor Cst to independently drive the OLED device A pixel circuit is provided.

The first and second switching TFTs ST1 and ST2 and the driving TFT DT are an amorphous silicon (a-Si) TFT, a poly-Si TFT, an oxide TFT, or an organic TFT. etc. may be used.

The OLED element has an anode connected to the driving TFT DT, a cathode connected to the low potential voltage EVSS, and a light emitting layer between the anode and the cathode. The anode is formed independently for each sub-pixel, but the cathode is formed so that all sub-pixels share it. The light emitting layer may include a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, an electron injection layer, etc. sequentially stacked between the anode and the cathode, and a functional layer for improving the luminous efficiency and / or lifespan of the organic light emitting layer. may include more. In the OLED device, when a positive bias is applied between the anode and the cathode, electrons from the cathode are supplied to the organic light emitting layer via the electron injection layer and the electron transport layer, and holes from the anode are transferred to the organic light emitting layer via the hole injection layer and the hole transport layer. is supplied Accordingly, the organic light emitting layer emits light proportional to the amount of current supplied from the driving TFT DT by emitting a fluorescent or phosphorescent material by recombination of supplied electrons and holes.

The first switching TFT ST1 is driven by the scan signal of one gate line GL1 to supply the data voltage Vdata from the corresponding data line DL to the gate node of the driving TFT DT. The second switching TFT ST2 is driven by the scan signal of the other gate line GL2 to supply the reference voltage Vref from the corresponding reference line RL as an initialization voltage to the source node of the driving TFT DT. The second switching TFT ST2 is further used as a path for outputting the current from the driving TFT DT to the reference line RL in the sensing mode.

The storage capacitor Cst is connected between the gate node and the source node of the driving TFT DT. The storage capacitor Cst is a voltage difference between the data voltage Vdata supplied to the gate node through the first switching TFT ST1 and the reference voltage Vref supplied to the source node through the second switching TFT ST2. Vdata-Vref) is charged and supplied to the driving voltage Vgs of the driving TFT DT.

The driving TFT DT controls the current supplied from the high potential voltage EVDD supply line PL according to the driving voltage Vgs supplied from the storage capacitor Cst, thereby controlling the current Ids proportional to the driving voltage Vgs. ) to the OLED device to make the OLED device emit light.

Since the second switching TFT ST2 of each of the R/W/B/G sub-pixels shares one reference line RL, the characteristics of each of the R/W/B/G sub-pixels are different at different times. It may be sensed through the shared reference line RL. For example, when the characteristic of any one of the R/W/B/G sub-pixels is sensed, the data voltage for sensing is supplied to the sub-pixel to be driven, while the other sub-pixels have an off voltage ( black data voltage) may be supplied to be turned off.

5 is a diagram illustrating an example of a real-time sensing period of an OLED display device according to the present invention.

Referring to FIG. 5 , each frame includes a writing period and a blanking period. In each writing period, image data is written to each subpixel line sequentially. In each blanking period, the compensation information of the memory M is updated by sensing the characteristics of the sub-pixels for one horizontal line.

For example, in the blanking period of n frames, the α compensation value (α_cmp) of the subpixels is updated in the memory M by sensing the characteristics of the subpixels of n lines, and n+1 in the blanking period of the n+1 frame. The α compensation value (α_cmp) of the subpixels is updated in the memory M by sensing the characteristics of the subpixels of the line, and the characteristics of the subpixels of the n+2 line are sensed in the blanking period of the n+2 frame to the memory ( In M), the α compensation value (α_cmp) of the corresponding subpixels is updated.

Meanwhile, in each blanking period, sub-pixels of a corresponding horizontal line may be separated by color and sensed. For example, when the display panel has N horizontal lines, R subpixels are sensed in units of horizontal lines every blanking period of N frames, and then W subpixels are configured in units of horizontal lines every blanking period of N frames. Then, after sensing the B subpixels in the same way, the G subpixels may be sensed.

FIG. 6 is a block diagram specifically illustrating an internal configuration of the image processing unit 200 illustrated in FIG. 2 .

The image processing unit 200 illustrated in FIG. 6 includes a current control unit 210 , a data conversion unit 220 , a compensation unit 230 , and the like. In addition, the image processing unit 200 converts R/G/B data input from an external system into R/G/B/W data through a predetermined operation and outputs a four-color conversion unit (not shown) to the current control unit 210 . not) may be additionally included.

The current controller 210 determines the peak luminance and total current of each frame by using image data input from an external system, determines a high potential voltage according to the peak luminance and the total current, and supplies it to the data driver 20 .

The current control unit 210 detects the number of pixels having peak luminance in each frame, that is, an average picture level (hereinafter referred to as APL) indicating an area occupied by white pixels in one screen, using grayscale data as input image data, , determine the peak luminance according to the detected APL. The current controller 210 determines the peak luminance corresponding to the APL by using the LUT in which the peak luminance for the APL is previously stored in an internal memory (not shown). In order to reduce power consumption, the peak luminance is determined to be inversely proportional to the APL. That is, a relatively small peak luminance is determined as the APL is larger (brighter image), and a relatively large peak luminance is determined as the APL is small (darker image).

In addition, the current controller 210 calculates the total current for each frame by summing the current values for the grayscale data by using the LUT in which the current values for each R/G/B/W grayscale data are previously stored in the internal memory. The current controller 210 adjusts the peak luminance determined according to the APL according to the total current to determine the final peak luminance, determines the high potential voltage corresponding to the final peak luminance, and outputs it to the data driver 20 . Also, the current controller 210 outputs grayscale data to the data converter 220 .

The data converter 220 converts grayscale data, which is image data input from the current controller 210 , into voltage data, and outputs the converted grayscale data to the compensator 230 . Specifically, the data conversion unit 220 converts the R/G/B/W grayscale data using a LUT in which voltage data for each R/G/B/W grayscale data is previously stored in an internal memory (not shown). It is converted into R/G/B/W voltage data and output to the compensator 230 . Since all of the compensation information Vth and α_cmp stored in the memory M are voltage values, image data, which is grayscale data, is converted into voltage data for compensation using them.

The compensator 230 compensates the voltage data input from the data converter 220 in the sensing mode and the display mode by using the compensation information stored in the memory M, and outputs the compensated voltage data to the data driver 20 . do. Also, the compensator 230 updates compensation information of the memory M by using a sensing value sensed from each subpixel of the display panel 40 through the data driver 20 in the sensing mode. In particular, the compensator 230 uses the display mobility compensation coefficient DTE1 for data compensation in the display mode, and uses the sensing mobility compensation coefficient DTE2 for data compensation in the sensing mode.

Specific operations of the compensation unit 230 in the sensing mode and the display mode will be described with reference to FIG. 7 .

7 is a flowchart illustrating a driving method in a sensing mode and a display mode of an OLED display device according to an embodiment of the present invention in stages.

Referring to FIG. 7A , in the sensing mode, the compensator 230 reads the mobility compensation value α_cmp and the sensing mobility compensation coefficient DTE2 of the corresponding sub-pixel from the memory M, and the following equation The same operation as 4 is performed to calculate the gain value (g), and the voltage data for sensing using the calculated gain value (g) and the threshold voltage compensation value (Vth) of the corresponding sub-pixel read from the memory (M) ( Vdata) and output the compensated voltage data MVdata to the data driver 20 (S12).

<Equation 4>

g = DTE2×(α_cmp - 1) + 1

MVdata = g×Vdata + Vth

Subsequently, the data driver 20 converts the compensated voltage data MVdata into an analog data voltage and supplies it to the data line DL, and also supplies the reference voltage Vref2, which is an initialization voltage, to the reference line RL and the corresponding sub After driving the pixel, the current output from the corresponding sub-pixel is sensed (S14).

In the corresponding subpixel shown in FIG. 4 , the storage capacitor Cst includes the data voltage MVdata supplied from the data line DL through the first switching TFT ST1 and the second switching TFT ST2 from the reference line RL. ) by charging the difference voltage (MVdata-Vref2 = Vgs) of the reference voltage Vref2 supplied through the driving TFT (DT), the driving TFT (DT) is a current proportional to the gate-source voltage (Vgs) to output

The data driver 20 senses a voltage corresponding to a current output from the driving TFT DT of the corresponding sub-pixel to the reference line RL through the second switching TFT ST2, converts it into digital sensing information, and converts it to a compensating unit ( 230) is supplied. The data driver 20 causes the current output from the driving TFT DT to the reference line RL through the second switching TFT ST2 to be stored as a voltage in a capacitor connected in parallel with the reference line RL, and then the capacitor voltage is converted into digital sensing information and supplied to the compensator 230 .

Next, the compensator 230 processes the sensing information from the data driver 20 to update the mobility compensation value α_cmp (S16).

The compensator 230 detects the mobility sensed value α_sen from the sensed information from the data driver 20, and reads the mobility sensed value α_sen and the memory M as a reference value as shown in Equation 5 below. After calculating the mobility error value Δα, which is the difference from the obtained mobility average value α_avg, the mobility compensation value α_cmp is updated using the mobility error value Δα.

<Equation 5>

Δα = α_sen - α_avg

α_cmp' = α_cmp + Δα/γ

The compensator 230 corrects the mobility compensation value α_cmp by adding the mobility error value Δα and the mobility compensation value α_cmp read from the memory M, and the corrected mobility compensation value α_cmp ') is stored in the memory M to update the mobility compensation value α_cmp. At this time, the compensator 230 calculates the ratio (Δα/γ) of the mobility error value (Δα) and the predetermined proportional coefficient (γ) as shown in Equation (5) to calculate the correction value (Δα/γ) to be actually used. Then, the mobility compensation value (α_cmp) is updated by adding the correction value (Δα/γ) to the mobility compensation value (α_cmp). The predetermined proportional coefficient γ is preset by the designer to be variable according to the characteristics of the product model (eg, sensing voltage, sensing period, etc.). For example, when Δα changes by 8 when the mobility compensation value α_cmp changes by 1, the proportional coefficient γ is set to 1.

Referring to FIG. 7B , in the display mode, the compensator 230 reads the updated mobility compensation value α_cmp′ and the display mobility compensation coefficient DTE1 of the corresponding subpixel from the memory M. A gain value (g') is calculated by performing an operation as in Equation 6 below, and the calculated gain value (g') and the threshold voltage compensation value (Vth) of the corresponding sub-pixel read from the memory M are used to calculate the gain value (g'). The display voltage data Vdata is compensated, and the compensated voltage data MVdata' is output to the data driver 20 (S22).

<Equation 6>

g' = DTE1×(α_cmp' - 1) + 1

MVdata' = g'×Vdata + Vth

The data driver 20 converts the voltage data MVdata' compensated by the compensation unit 230 into an analog signal and supplies it to each sub-pixel, so that the display panel 40 displays an image (S24).

The data driver 20 supplies the data voltage MVdata' to the data line DL, and also supplies the reference voltage Vref1, which is an initialization voltage, to the reference line RL. In the corresponding subpixel shown in FIG. 4 , the storage capacitor Cst includes the data voltage MVdata′ supplied from the data line DL through the first switching TFT ST1 and the second switching TFT ST1 from the reference line RL. The driving TFT DT is driven by charging the difference voltage MVdata'-Vref1 = Vgs of the reference voltage Vref1 supplied through ST2), and the driving TFT DT is proportional to the gate-source voltage Vgs. The current is output to the OLED device to make the OLED device emit light.

As described above, the OLED display device according to the present invention achieves optimal mobility compensation in the display mode and the sensing mode by using the mobility compensation coefficient for display optimized for the display mode and the mobility compensation coefficient for sensing optimized for the sensing mode. can be done Accordingly, the accuracy of the mobility compensation is improved, thereby improving the image quality.

On the other hand, in the OLED display device according to the present invention, since the sensing voltage data for each panel is fixed in the sensing mode, the mobility compensation coefficient for sensing for the sensing voltage data is also preset and stored as a fixed coefficient. Therefore, there is a further need for a method of detecting by tracking the mobility compensation coefficient for sensing optimized for each panel. This means that the voltage data for sensing is set differently for each panel in consideration of the distribution of the mobility sensed from the panel, and even if the voltage data for sensing is the same, the optimum sensing mobility compensation coefficient required for each panel due to panel deviation is Because it can be different.

Hereinafter, a method and apparatus for detecting a mobility compensation coefficient for sensing in an OLED display device according to another embodiment of the present invention will be described.

8 is a flowchart illustrating a method of detecting a mobility compensation coefficient for sensing in an OLED display device according to another exemplary embodiment in a step-by-step manner.

The method for detecting a mobility compensation coefficient for sensing of an OLED display device according to the present invention samples a specific line to obtain a mobility compensation coefficient (DTE) in which the slope of the updated mobility sensed value with respect to the initial mobility sensed value is close to “0”. detect The detected mobility compensation coefficient is set as the mobility compensation coefficient for sensing of the corresponding panel and stored in the register. Mobility compensation coefficients for sensing are detected for each color and stored in a register. The method of detecting the mobility compensation coefficient for sensing of the OLED display device is performed before product shipment, but may be executed even after product shipment if necessary.

In step 32 ( S32 ), any one of the mobility compensation coefficients (DTE) is applied to perform mobility update sensing for any one sampling line, and the updated mobility sensing value α_sen' for each subpixel of the sampling line is performed. ) is detected.

^{The mobility compensation value (α_cmp = {α_avg/α_sen} 1/2} ) is calculated using the initial mobility sensing value (α_sen) for each subpixel from the memory and the mobility average value (α_avg) for each color as a reference value, and the mobility A gain value (g = DTE × (α_cmp - 1) + 1) of each sub-pixel is calculated using the compensation value (α_cmp) and any one of the mobility compensation coefficients (DTE). The data voltage Vdata is compensated by multiplying the calculated gain value g by the data voltage Vdata and adding a threshold voltage compensation value Vth for each sub-pixel from the memory. The updated mobility sensing value α_sen for each subpixel of the sampling line is driven by driving each subpixel of the sampling line using the compensated data voltage MVdata, and then sensing a voltage corresponding to a current output from each subpixel. ') is detected.

In step 34 ( S34 ), a first slope of a straight line representing the updated mobility sensed value α_sen′ with respect to the initial mobility sensed value α_sen is calculated.

Referring to FIG. 9 , it can be seen that the first slope of the updated mobility sensed value α_sen′ with respect to the initial mobility sensed value α_sen of the sampling line is different according to the mobility compensation coefficient DTE.

In the case of initial sensing, the mobility compensation value required for each sub-pixel is calculated by sensing the initial mobility distribution. In the case of update sensing, the mobility compensation value calculated in the initial sensing is applied to the voltage data, so the mobility for each sub-pixel is The scatter is reduced and it has the characteristic of converging to a constant value. The mobility compensation coefficient (DTE) affects the degree of convergence of the update sensing by adjusting the mobility compensation value calculated in the initial sensing. As a result of examining the relationship between the mobility of the initial sensing and the mobility of the updater sensing, it can be seen that the slope varies according to the mobility compensation coefficient (DTE) as shown in FIG. 9. When the slope is “0”, the convergence characteristic of the update sensing is You can tell it's in the best condition. Accordingly, the optimal sensing mobility compensation coefficient DTE may be calculated using a straight line that is a correlation between the first slope indicating the degree of convergence of the update sensing and the mobility compensation coefficient DTE.

In step 36 (S36), the second slope of the straight line representing the first slope with respect to the mobility compensation coefficient DTE is calculated, and the mobility of the point where the first slope corresponds to “0” in the straight line having the second slope. The compensation factor (DTE) is calculated, set as the optimal sensing DTE, and stored in a register.

As a result of examining the change trend of the first slope according to the six mobility compensation coefficients (DTE) shown in FIG. 9, it can be seen that the first slope with respect to the mobility compensation coefficient (DTE) has a linear relationship as shown in FIG. could

Therefore, it is not necessary to detect all of the first slopes for a plurality of mobility compensation coefficients (DTEs) as shown in FIG. 9, and only the first slopes for any one mobility compensation coefficient (DTE) are calculated, and FIG. The second slope of the straight line representing the first slope with respect to the mobility compensation coefficient DTE and the mobility compensation coefficient DTE of a point at which the first slope is “0” may be calculated using this.

Specifically, in FIG. 10 , when the mobility compensation coefficient (DTE) is “0”, it is the same as when no mobility compensation is performed, so the updated mobility sensed value α_sen' with respect to the initial mobility sensed value α_sen. The first slope of is unconditionally “1”, and the corresponding first point P1 is fixed as the reference point. A second point P2 corresponding to a first slope for any one of the mobility compensation coefficients DTE detected in step 34 (S34) is detected, and the first and second points P1 and P2 are connected. Calculate the second slope of the straight line. Using the second slope between the first and second points P1 and P2, the mobility compensation coefficient DTE of the third point P3 where the first slope corresponds to “0” as in Equation 7 below Calculated and set as the optimal sensing mobility compensation coefficient (DTE), and stored in the register.

<Equation 7>

Optimal sensing DTE = -1/second slope

For example, if the DTE of P2 is 0.8 and the first slope is 0.03, then the second slope is (0.03-1)/(0.8-0) = -1.2125, and the DTE of P3 is -1/-1.2152 = 0.8247 .

Steps 32 to 36 (S32 to S36) described above are repeatedly executed for each color, so that the optimal sensing mobility compensation coefficient (DTE) for each panel is set for each color and stored in a register.

As described above, since the OLED display device according to the present invention has a characteristic deviation for each panel, it is possible to detect and apply a sensing mobility compensation coefficient optimized for each panel.

11 is a block diagram illustrating an internal configuration of an image processing unit 200' of an OLED display device according to another embodiment of the present invention.

In contrast to the image processing unit 200 shown in FIG. 6 , the image processing unit 200 ′ shown in FIG. 11 has the same components except for additionally including the sensing DET detection unit 240 , so the overlapping components are identical. A description of the components will be omitted.

The sensing DTE detection unit 240 detects the sensing DTE optimized for each panel by color by executing the sensing DTE detection method shown in FIG. 8 , and the memory M or the image processing unit 200 ′, that is, the timing controller 10 ( FIG. 2 ). ) is stored in the built-in register (R). The sensing DTE detection unit 240 samples a specific line and detects a mobility compensation coefficient (DTE) having a first slope of an updated mobility sensed value close to “0” for each color, and registers (R) save to The sensing mobility compensation coefficient for each color optimized for each panel is applied during real-time mobility update sensing.

Meanwhile, in the sensing mode before product shipment, the compensator 230 updates and senses the mobility of each sub-pixel for each color by applying the sensing mobility compensation coefficient, the mobility compensation value, and the threshold voltage compensation value, and the color A value at which the updated mobility sensing values for each color converge may be set as a mobility reference value for each color and stored in the register M.

12 is a diagram illustrating a comparison of the convergence characteristics of update sensing when the conventional display mobility compensation coefficient is applied and the case in which the sensing mobility compensation coefficient of the present invention is applied.

Referring to FIG. 12A , as a result of updating and sensing the mobility of the white subpixels by applying the conventional display mobility compensation coefficient, it can be seen that the sensed values of the mobility have various values and are distributed.

Referring to FIG. 12(b), as a result of updating and sensing the mobility of white sub-pixels by applying the mobility compensation coefficient for sensing according to the present invention, it can be seen that the sensed values of the mobility converge to almost the same value. there is. Accordingly, the convergence value of the mobility for each color sensed by applying the mobility compensation coefficient for sensing for each color according to the present invention is stored in the register as a mobility reference value for each color (that is, the average value of the mobility for each color) during real-time compensation. can be used by

As described above, the OLED display device according to the present invention can improve the accuracy of the sensing value and the compensation value by sensing the mobility characteristics of each sub-pixel by applying a compensation coefficient for sensing different from the compensation coefficient for display in the sensing mode. Therefore, the picture quality can be improved.

In addition, the OLED display device according to the present invention senses the mobility characteristics of each sub-pixel by calculating the compensation factor for sensing optimized for each panel and applying the compensation factor for sensing optimized according to the characteristics of the panel as well as the data voltage for sensing. By doing so, the accuracy of the sensing value and the compensation value can be improved, so that the image quality can be improved.

In addition, the OLED display device according to the present invention can sense and compensate for mobility characteristics sensitive to temperature and light at high speed by updating the mobility compensation value through update sensing to which a compensation coefficient optimized for sensing is applied.

Accordingly, the OLED display device according to the present invention improves the accuracy of the mobility compensation value by applying the compensation coefficient for sensing optimized for each panel and improving the convergence characteristic of the sensing values with respect to the reference value (average value) during update sensing. The picture quality can be improved.

In the above, it has been shown and described as a specific embodiment to illustrate the technical idea of the present invention, but the present invention is not limited to the same configuration and operation as the specific embodiment as described above, and various modifications do not depart from the technical spirit of the present invention. It can be implemented within the scope. Accordingly, such modifications should be considered to fall within the scope of the present invention, and the scope of the present invention should be determined by the following claims.

10: timing controller 20: data driver
30: gate driver 40: display panel
100: control signal generating unit 200, 200': image processing unit
210: current control unit 220: data conversion unit
230: compensation unit 240: sensing DTE detection unit
M: memory R: register

Claims (18)

An organic light emitting diode (OLED) display device, characterized in that the mobility compensation coefficient for sensing applied to data in the sensing mode is set to a different value from the mobility compensation coefficient for display applied to the data in the display mode. The method according to claim 1,
A display panel including a plurality of subpixels having different colors;
a memory storing compensation information for compensating for characteristics of each sub-pixel, and at least one of the display mobility compensation coefficient and the sensing mobility compensation coefficient;
In the display mode, the data to be supplied to each sub-pixel is compensated by applying the compensation information and the display mobility compensation coefficient, and in the sensing mode, the data is compensated by applying the compensation information and the sensing mobility compensation coefficient. and a data processing unit that compensates for , senses a characteristic of each sub-pixel using the compensated data, and updates the compensation information using a sensed value sensed from each sub-pixel;
The sensing mobility compensation coefficient is stored in one of the memory and the register of the data processing unit. 3. The method according to claim 2,
The compensation information stored in the memory includes a mobility compensation value for compensating for mobility characteristics of a driving thin film transistor (hereinafter, TFT) of each sub-pixel, a threshold voltage compensation value for compensating a threshold voltage of the driving TFT, and Includes a mobility reference value for each color used as a reference value when updating the mobility compensation value,
The display mobility compensation coefficient is set according to voltage data for each color and each gradation,
The sensing mobility compensation coefficient is set for each color according to at least one sensing data, or is set for each color according to the at least one sensing data for each panel. 3. The method according to claim 2,
When a voltage corresponding to the compensated data is supplied to a gate node of the driving TFT, an initialization voltage applied to another node of the driving TFT is different from each other in the sensing mode and the display mode. 4. The method according to claim 3,
The data processing unit includes a compensation unit and a data driver,
the compensation unit
In the display mode, the data is compensated by applying the mobility compensation value, the display mobility compensation coefficient, and the threshold voltage compensation value, and the compensated data is supplied to the corresponding sub-pixel through the data driver;
In the sensing mode, the data is compensated by applying the mobility compensation value, the sensing mobility compensation coefficient, and the threshold voltage compensation value, and the compensated data is supplied to the corresponding sub-pixel through the data driver, OLED, characterized in that a signal output from a pixel is sensed through the data driver to detect a mobility sensed value, and the mobility compensation value is updated using an error value between the mobility sensed value and the mobility reference value. display device. 6. The method of claim 5,
The data processing unit
The initial mobility sensing value of each sub-pixel and the updated mobility sensing value obtained by sensing the mobility of each sub-pixel by applying any one mobility compensation coefficient, the mobility compensation value, and the threshold voltage compensation value are used and a mobility compensation coefficient detector for sensing to detect the mobility compensation coefficient for sensing. 7. The method of claim 6,
The sensing mobility compensation coefficient detection unit
In the sensing mode before product shipment,
calculating a first slope of a first straight line representing the relationship between the updated mobility sensed value and the initial mobility sensed value by applying any of the mobility compensation coefficients,
calculating a second inclination of a second straight line representing the relationship of the first inclination to the mobility compensation coefficient;
and detecting a mobility compensation coefficient at a point where the first slope becomes “0” on the second straight line and setting it as the sensing mobility compensation coefficient. 8. The method of claim 7,
The sensing mobility compensation coefficient detection unit
The second point connecting a first point where the mobility compensation coefficient is “0” and the first slope is “1”, and a second point indicating the calculated first slope with any one of the mobility compensation coefficients The OLED display device, characterized in that the second inclination is calculated from the linear relationship. 9. The method according to any one of claims 5 to 8,
the compensation unit
In the sensing mode before product shipment,
The value at which the updated mobility sensing value for each color converges by sensing the mobility of each subpixel for each color by applying the mobility compensation coefficient for sensing, the mobility compensation value, and the threshold voltage compensation value for each color OLED display device, characterized in that it is set as a mobility reference value and stored in the memory. Compensate the data by applying the mobility compensation coefficient for display in display mode,
and compensating for the data by applying a mobility compensation coefficient for sensing different from the mobility compensation coefficient for display in a sensing mode. 11. The method of claim 10,
compensating for data to be supplied to each sub-pixel by applying compensation information of each sub-pixel stored in the memory in the display mode and the mobility compensation coefficient for display;
In the sensing mode
compensating for the data by applying the compensation information of each sub-pixel stored in the memory and the mobility compensation coefficient for sensing stored in any one of the memory and the register;
sensing a characteristic of each sub-pixel using the compensated data;
and updating the compensation information by using a sensed value sensed from each of the sub-pixels. 12. The method of claim 11,
The compensation information stored in the memory includes a mobility compensation value for compensating for the mobility characteristic of the driving TFT of each sub-pixel, a threshold voltage compensation value for compensating a threshold voltage of the driving TFT, and the mobility compensation value. Includes a mobility reference value for each color that is used as a reference value when updating,
The display mobility compensation coefficient is set according to voltage data for each color and each gradation,
The sensing mobility compensation coefficient is set for each color according to at least one sensing data, or is set for each color according to the at least one sensing data for each panel. 12. The method of claim 11,
When the voltage corresponding to the compensated data is supplied to the gate node of the driving TFT, the initialization voltage applied to the other node of the driving TFT is different in the sensing mode and the display mode. method. 13. The method of claim 12,
In the sensing mode,
compensating for the data by applying the mobility compensation value, a sensing mobility compensation coefficient, and a threshold voltage compensation value, and supplying the compensated data to drive a corresponding sub-pixel;
detecting a mobility sensing value by sensing a signal output from the driven sub-pixel;
and updating the mobility compensation value by using an error value between the mobility sensing value and the mobility reference value. 15. The method of claim 14,
The initial mobility sensing value of each sub-pixel, the updated mobility sensing value obtained by sensing the mobility of each sub-pixel by applying any one mobility compensation coefficient, the mobility compensation value, and the threshold voltage compensation value are used. and detecting the mobility compensation coefficient for sensing. 16. The method of claim 15,
The step of detecting the mobility compensation coefficient for sensing comprises:
In the sensing mode before product shipment,
calculating a first slope of a first straight line representing a relationship between the updated mobility sensed value and the initial mobility sensed value by applying any one of the mobility compensation coefficients;
calculating a second inclination of a second straight line representing the relationship of the first inclination to the mobility compensation coefficient;
and detecting a mobility compensation coefficient at a point where the first slope becomes “0” on the second straight line and setting it as the sensing mobility compensation coefficient. 17. The method of claim 16,
Calculating the second slope of the second straight line comprises:
The second point connecting a first point where the mobility compensation coefficient is “0” and the first slope is “1”, and a second point indicating the calculated first slope with any one of the mobility compensation coefficients and calculating the second inclination from the linear relationship. 18. The method according to any one of claims 14 to 17,
In the sensing mode before product shipment,
sensing the mobility of each sub-pixel for each color by applying the sensing mobility compensation coefficient, the mobility compensation value, and the threshold voltage compensation value;
The method of driving an OLED display device according to claim 1, further comprising: setting a value at which the updated mobility sensing value for each color converges according to the sensing result as the mobility reference value for each color and storing the value in the memory.

Images