KR20190142124A - Sensing method of organic light emitting diode display device - Google Patents

Abstract

The present invention relates to a method for simultaneously sensing mobility of a driving TFT of sub pixels of at least two lines, and more specifically, to a sensing method for an organic light emitting diode display device, which increases a sensing current to reduce sensing time. To this end, the sensing method for an organic light emitting diode display device, which is configured such that the mobility of a driving TFT may be sensed by one reference signal line in m number of sub pixels successively aligned in a horizontal direction, comprises: a step that (m-1) number of sub pixels are selected among the m number of sub pixels, wherein an m number of combinations are selected such that the combinations of the selected (m-1) number of sub pixels may not be overlapped (Here, m is a natural number of 3 or more); a step that the current of the driving TFT of the selected (m-1) number of sub pixels of each combination is simultaneously sensed; a step that the sensed current of the m number of combinations is added up; and a step that the current of the driving TFT of each sub pixel is calculated by subtracting the sensed current value of each combination from the added-up sensed current value.

Description

SENSING METHOD OF ORGANIC LIGHT EMITTING DIODE DISPLAY DEVICE}

The present invention relates to a sensing method of an organic light emitting diode display device capable of sensing mobility of a driving TFT in a short time.

Recently, a display device for displaying an image using digital data includes a liquid crystal display (LCD) using a liquid crystal, an organic light emitting diode (OLED) display using an organic light emitting diode, and an electrophoretic particle. Electrophoretic Display (EPD) is a typical example.

Among these, an OLED display device is a self-luminous device that emits an organic light emitting layer by recombination of electrons and holes. The OLED display device is expected to be a next-generation display device because of its high brightness, low driving voltage, and ultra-thin film.

Each pixel constituting the OLED display device includes an OLED element and pixel circuits that independently drive the OLED element. The pixel circuit adjusts the brightness of the OLED device by adjusting a current Ids of the driving thin film transistor (TFT) driving the OLED device according to the driving voltage Vgs corresponding to the image data.

The OLED display device has a current value (Ids) compared to the driving voltage (Vgs) of the same gray level when the characteristics of the subpixels are uneven due to the threshold voltage (hereinafter referred to as Vth) and mobility of the driving TFT that vary depending on process variation, driving environment, and driving time. Since the brightness irregularity phenomenon may occur.

In order to solve this problem, the OLED display mainly uses a technique of sensing the characteristics of the subpixel and compensating for the variation of the characteristics of the subpixel based on the sensing result.

The threshold voltage change amount of the driving TFT and the method and period for sensing the change amount of mobility of the driving TFT are respectively different.

In the sensing method for extracting the change in the threshold voltage Vth of the driving TFT, the driving TFT is operated in a source follower method, and then the source voltage of the driving TFT is sensed to determine the amount of change in the threshold voltage of the driving TFT based on the sensing voltage. Detect. The amount of change in the threshold voltage of the driving TFT is determined according to the magnitude of the sensing voltage, thereby obtaining an offset value for data compensation. In this sensing method, since the sensing operation must be performed after the gate-source voltage Vgs of the driving TFT operated by the source follower method reaches a saturation state, the sensing time is long and the sensing speed is high. It is slow.

The sensing method for extracting the change in mobility (μ) of the driving TFT is a constant voltage (Vdata) higher than the threshold voltage of the driving TFT in the gate of the driving TFT in order to define the current capability characteristic except the threshold voltage (Vth) of the driving TFT. + X, where X is a voltage according to offset value compensation) to turn on the driving TFT, and in this state, the source voltage Vs of the driving TFT charged for a predetermined time is input as the sensing voltage. The amount of change in mobility of the driving TFT is determined according to the magnitude of the sensing voltage, thereby obtaining a gain value for data compensation. Since the sensing method is performed while the driving TFT is turned on, the sensing time is short and the sensing speed is high.

The method of sensing the mobility of the driving TFT may be performed in the blank period within the image display driving period because the sensing speed is faster than that of the sensing threshold voltage of the driving TFT.

However, in the conventional method for sensing the mobility of the driving TFT, since the mobility of the driving TFT is sensed line by line, the sensing current is low and the time for sensing the mobility of the driving TFT is long, so that the mobility of the driving TFT is increased. There was a limit to accurate sensing.

Accordingly, there is a problem in that image quality defects such as horizontal lines are generated due to a decrease in the accuracy of compensation using the mobility sensing value of the driving TFT.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and the sensing of the organic light emitting diode display device which can reduce the sensing time by increasing the sensing current by simultaneously sensing the mobility of the driving TFTs of at least two lines of sub pixels. The purpose is to provide a method.

According to an aspect of the present invention, there is provided a method of sensing an organic light emitting diode display, wherein m subpixels arranged in a horizontal direction are configured to sense mobility of a driving TFT by one reference signal line. In the sensing method of the organic light emitting diode display, selecting (m-1) subpixels of m subpixels, but m combinations are selected so that the combination of the selected (m-1) subpixels do not overlap Step, where m is a natural number of at least 3; Simultaneously sensing current of the driving TFTs of the selected (m-1) sub-pixels of each combination; Summing the sensed currents of the m combinations; And calculating the current of the driving TFT of each sub-pixel by subtracting the sensed current value of each combination from the summed sensing current value.

A voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected (m-1) subpixels, and a voltage of 0V or no voltage is applied to the data lines of the other subpixels. It features.

In addition, the sensing method of the organic light emitting diode display according to the present invention for achieving the above object, while selecting three of the sub-pixels among the four sub-pixels arranged in a horizontal direction, the selected three sub-pixels Selecting a combination of four such that the combination of the two does not overlap; Simultaneously sensing currents of the driving TFTs of the selected three sub-pixels of each combination; Summing the sensed currents of the four combinations; And subtracting the sensed current values of each combination from the sum of the sensed current values to calculate the current of the driving TFT of each sub-pixel.

A voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected three subpixels, and a voltage of 0V or no voltage is applied to the data lines of the other subpixels.

In addition, the sensing method of the organic light emitting diode display according to the present invention for achieving the above object, while selecting two of the sub-pixels among the four sub-pixels arranged in a horizontal direction, the selected two sub-pixels Selecting a combination of six such that the combination of the two does not overlap; Simultaneously sensing current of the driving TFTs of the selected two sub-pixels of each combination; Summing the six combinations of sensed currents; And selecting and summing three sensed currents among the six combination sensed currents to calculate four sets of summing currents so that the sensed currents of the three subpixels do not overlap. And calculating the current of the driving TFT of each sub-pixel by subtracting each set of sum currents from the sum of the six combinations of sensed current values.

A voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected two subpixels, and a voltage of 0V or no voltage is applied to the data lines of the remaining two subpixels.

In addition, in the sensing method of the organic light emitting diode display according to the present invention for achieving the above object, while selecting two sub-pixels of the three sub-pixels arranged in a horizontal direction, two selected sub-pixels Selecting a combination of three such that the combination of the two does not overlap; Simultaneously sensing current of the driving TFTs of the selected two sub-pixels of each combination; Summing the three combined sensed currents; And subtracting the sensed current values of each combination from the sum of the sensed current values to calculate the current of the driving TFT of each sub-pixel.

A voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected two subpixels, and a voltage of 0V or no voltage is applied to the data lines of the other subpixels.

The sensing method of the OLED display device according to the exemplary embodiment of the present invention has the following effects.

First, since the current of the driving TFTs of at least two sub-pixels is sensed simultaneously as in the present invention, the sensed current is high, so that the current of the driving TFTs can be sufficiently sensed within the blank period without lengthening the sensing period. Therefore, sensing noise due to lack of sensing time can be reduced.

Second, when the currents of the driving TFTs of the at least two subpixels are sensed at the same time, the sensed current is high, and thus the sensing period can be shortened, thereby reducing the sensing time.

1 is a block diagram schematically illustrating a configuration of an OLED display device according to an exemplary embodiment of the present invention.
2 is an equivalent circuit diagram illustrating one subpixel circuit according to an exemplary embodiment of the present invention.
3 is a timing diagram of a scan pulse, a sensing signal, a sampling signal, a reference voltage, and a sensing voltage during sensing driving according to the present invention.
4A through 4D are equivalent circuit diagrams illustrating a plurality of subpixel circuits according to a first exemplary embodiment of the present invention.
5 is an equivalent circuit diagram illustrating a plurality of subpixel circuits according to a second exemplary embodiment of the present invention.
6A through 6C are equivalent circuit diagrams illustrating a plurality of subpixel circuits according to a first exemplary embodiment of the present invention.
7 is a graph showing a change in current value of the driving TFT according to the present invention.

Hereinafter, an organic light emitting diode display and a sensing method thereof according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram schematically showing the configuration of an OLED display device according to an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram illustrating the configuration of one sub-pixel shown in FIG. 1, and FIG. The timing diagram of the scan pulse, the sensing signal sense, the sampling signal sam, the reference voltage ref, and the sensing voltage Vref during the sensing driving.

Referring to FIG. 1, an OLED display according to an exemplary embodiment may include a display panel 100, a gate driver 200, a data driver 300, a timing controller 400, a memory 500, and a power supply 600. Include.

The display panel 100 displays an image through a pixel array in which sub-pixels SP are arranged in a matrix. The basic pixel may include at least three subpixels among white (W), red (R), green (G), and blue (B) subpixels. For example, the base pixel may be a subpixel of an R / G / B combination, a subpixel of a W / R / G combination, a subpixel of a B / W / R combination, or a subpixel of a G / B / W combination. Or sub-pixels of a W / R / G / B combination.

Referring to FIG. 2, each sub-pixel SP is connected between a high potential driving voltage (first driving voltage; EVDD) line PW1 and a low potential driving voltage (second driving voltage; EVSS) line PW2. Pixel circuit including at least the connected OLED element 10 and the first and second switching TFTs ST1 and ST2 and the driving TFT DT and the storage capacitor Cst to independently drive the OLED element 10. It is provided. In the meantime, various configurations different from those of FIG. 2 may be applied to the pixel circuit.

As the switching TFTs ST1 and ST2 and the driving TFT DT, an amorphous silicon (a-Si) TFT, a poly-Si TFT, an oxide TFT, an organic TFT, or the like may be used. Can be.

The OLED element 10 includes an anode connected to the source node N2 of the driving TFT DT, a cathode connected to the EVSS line PW2, and an organic light emitting layer between the anode and the cathode. The anode may be independent for each subpixel, but the cathode may be a common electrode shared by all subpixels. In the OLED device 10, when a driving current is supplied from the driving TFT DT, electrons from the cathode are injected into the organic light emitting layer, holes from the anode are injected into the organic light emitting layer, and electrons are emitted from the organic light emitting layer. And emitting light of fluorescent or phosphorescent material by recombination of holes, thereby generating light having a brightness proportional to the current value of the driving current.

The first switching TFT ST1 is driven by the first gate signal SCAN supplied from the gate driver 200 to the first gate line GLn1, and the data line DL from the data driver 300. The data voltage Vdata is supplied to the gate node N1 and the storage capacitor Cst of the driving TFT DT.

The second switching TFT ST2 is driven by the second gate signal SENSE supplied from the gate driver 200 to the second gate line GLn2, and the reference line REF from the data driver 300. The reference voltage Vref supplied to is supplied to the source node N2 of the driving TFT DT. In addition, when each sub-pixel SP is driven in the sensing mode, the second switching TFT ST2 outputs the current supplied from the driving TFT DT to the floating reference line REF.

The storage capacitor Cst connected between the gate node N1 and the source node N2 of the driving TFT DT is gated through the first and second switching TFTs ST1 and ST2 turned on during the scan period. The difference voltage between the data voltage Vdata and the reference voltage Vref supplied to the node N1 and the source node N2 is charged to the driving voltage Vgs of the driving TFT DT, and the first and second switching are performed. The charged driving voltage Vgs is held during the light emission period in which the TFTs ST1 and ST2 are turned off.

The driving TFT DT controls the current supplied from the EVDD line PW1 according to the driving voltage Vgs supplied from the storage capacitor Cst, thereby controlling the driving current determined by the driving voltage Vgs. The OLED element 10 is made to emit light by supplying with.

In the mode of sensing the characteristic of the driving TFT DT, the driving TFT DT is connected to the data line DL from the data driver 300 during the scan period of the first and second gate signals SCAN and SENSE. And a sensing data voltage Vdata supplied through the first switching TFT ST1 and a reference voltage Vref supplied through the reference line REF and the second switching TFT ST2. The current of the driving TFT DT reflecting the driving characteristics Vth (mobility) of the driving TFT DT is a line capacitor of the reference line REF (Cref of FIGS. 4A to 4D) through the second switching TFT ST2. ) And is sensed by the analog-to-digital converter (see FIG. 3) of the data driver 300.

The gate driver 200 receives a gate control signal from the timing controller 400 to drive a plurality of gate lines of the display panel 100. The gate driver 200 supplies a gate-on voltage pulse to a corresponding gate line in a driving (scan) period of each gate line, and supplies a gate-off voltage in a non-driving period. The gate driver 200 may be disposed on both sides of the display panel 100, and the delay of the gate signal may be reduced by simultaneously supplying gate signals from both sides of each gate line.

The gate driver 200 includes a plurality of gate integrated circuits (ICs) that divide and drive gate lines, and each gate IC is individually mounted on a circuit film such as a chip on film (COF) to display the display panel 100. It may be attached to one side or both sides of the. Alternatively, the gate driver 200 may be formed in a gate in panel (GIP) type which is directly formed in the non-display area of the substrate together with the TFT array of the pixel array of the panel 100 and embedded in the panel 100. .

The data driver 300 converts the data supplied from the timing controller 400 into an analog data voltage using the data control signal supplied from the timing controller 400 and supplies the data voltage to the display panel 100. do. The data driver 300 converts digital data into an analog data voltage using a gamma voltage for each gray level supplied from a gamma voltage generator.

When the data driver 300 is in a sensing mode under the control of the timing controller 400, the data driver 300 drives each subpixel by supplying a sensing data voltage to a data line and drives driving characteristics of the driven subpixel SP. The pixel current representing the Vth, mobility, Vth, etc. of the driving TFT is sensed as a voltage through the reference line REF, converted into digital sensing information (sensing data), and provided to the timing controller 400.

The data driver 300 may include a plurality of data ICs that divide and drive data lines, and each data IC may be mounted on each circuit film and attached to the display panel 100.

The power supply unit 600 generates and outputs various driving voltages (EVDD, EVSS, etc.) necessary for the timing controller 400, the gate driver 200, the data driver 300, and the display panel 100 using the input voltage. . For example, the power supply unit 600 may drive the driving voltages EVDD and EVSS and the reference voltage Vref supplied to the display panel 100 through the data driver 300, the data driver 300, the timing controller 400, and the like. Generates the driving voltage of the supplied digital circuit, the driving voltage of the analog circuit supplied to the data driver 300, the gate on voltage (gate high voltage) and gate off voltage (gate low voltage) used in the gate driver 200. Can be supplied.

Compensation information for each subpixel to be used in the timing controller 400 is stored in the memory 500, and is updated by using a sensing result of each subpixel obtained through a real-time sensing operation during the driving of the OLED display device. . For example, the compensation information of each subpixel may include a mobility compensation value of each subpixel for compensating for the variation in mobility of the driving TFTs between the subpixels, a Vth compensation value of each subpixel for compensating the Vth of the driving TFT, and the like. It includes.

The timing controller 400 receives image data and basic timing control signals from an external system. The system may be any one of a system of a portable terminal such as a computer, a TV system, a set top box, a tablet or a mobile phone. The basic timing control signals may include a dot clock, a data enable signal, a vertical sync signal, a horizontal sync signal, and the like.

The timing controller 400 drives the data driver 300 and the gate driver 200 using basic timing control signals supplied from the outside and timing setting information (start timing, pulse width, etc.) stored in an internal register. It generates and supplies data control signals and gate control signals that control timing, respectively.

For example, the gate control signals may include a gate start pulse (GSP) and a gate shift clock (GSC) for controlling a scan operation of the gate driver 200, and an output period of the gate signal. And a gate output enable (GOE). The data control signals include a source start pulse (SSP) and a source shift clock (SSC) for controlling a shift register operation in the data driver 300, and a source output for determining a data output period of the output buffer unit. It may include an Source Output Enable (SOE) signal.

The timing controller 400 compensates the image data to be supplied to each sub-pixel SP using a compensation value stored in the memory 500, and supplies the compensated image data to the data driver 300. The timing controller 400 may further perform various image processing for deterioration compensation of the OLED element 10, power consumption reduction, and the like.

The timing controller 400 may control the OLED display to operate in a sensing mode when it is determined that sensing is required by receiving a sensing command from a system or determining whether the panel needs sensing. The timing controller 400 may determine the sensing timing of the panel 100 by using bidirectional communication with the system or by driving time by itself.

In the sensing mode, the timing controller 400 controls the OLED display device to operate in the sensing mode, so that the characteristics (eg, Vth, of the driving TFT) of each subpixel of the display panel 100 are controlled through the data driver 300. Mobility, Vth of the OLED, etc.) and the compensation information for each sub-pixel stored in the memory 500 is updated using the sensing result.

For example, the timing controller 400 changes the mobility of the driving TFT sensitive to the driving environment such as temperature and light by using information sensed from a linear section in which the source voltage increases by driving the driving TFT in each sub-pixel. Is calculated and the mobility compensation value of each sub-pixel stored in the memory 500 is updated using the calculation result. The mobility sensing for updating the mobility compensation value operates in a fast mode in which the sensing time is relatively short. Therefore, the on sensing mode (ON RF) allocated to the power-on period is mainly used, and each frame of the display operation is performed. At least one of the real-time sensing mode (RT) assigned to the blank period of.

The timing controller 400 senses the Vth of the driving TFT by using the information of sensing the section in which the driving TFT is driven and the source voltage reaches the saturation state in each subpixel, and stores each of the Vths of the driving TFT in the memory 500 by using the sensing result. Update the Vth compensation value of the subpixel. The Vth compensation value compensates for the Vth deviation of the driving TFT between the subpixels and compensates for the Vth shifted by electrical stress as the driving time elapses. Since the Vth sensing for updating the Vth compensation value operates in a slow mode in which a sensing time is longer than that in the above-described fast mode, the Vth sensing may be mainly performed in an off sensing mode (OFF RS) allocated to a power off period.

As described above, the mobility sensing method of the driving TFT corresponds to a scan pulse and a sensing signal sense for the first gate line GLn1 and the second gate line GLn2, respectively. The first and second gate signals are applied in a high state and a reference voltage is supplied to the reference line REF. The driving TFT is turned on by applying a constant voltage Vdata higher than the threshold voltage of the driving TFT DT to the data line.

The first gate signal scan and the reference voltage ref are applied in a low state, and after a predetermined time, the sampling signal sam is made high to sense the current of the driving TFT.

However, since only the current of the driving TFT of one sub-pixel is sensed, the sensing current is low and the sensing time is long, and the sensing time is insufficient when sensing the mobility of the driving TFT in the blank period.

Accordingly, the present invention can simultaneously sense the mobility of the driving TFTs of a plurality of subpixels to increase the sensing current to shorten the sensing time, and to sufficiently secure the mobility sensing time of the driving TFT in the blank period.

4A through 4D are equivalent circuit diagrams illustrating a plurality of subpixel circuits according to a first exemplary embodiment of the present invention.

As shown in FIG. 4A to FIG. 4D, the configuration of each subpixel R, G, B, and W has a high potential driving voltage line EVDD and a low potential driving voltage line EVSS as described with reference to FIG. 2. At least a first and second switching TFTs ST1 and ST2 and a driving TFT DT and a storage capacitor Cst to independently drive the OLED device OLED connected to each other and the OLED device OLED. A pixel circuit is provided.

In addition, in the circuit configuration of the organic light emitting diode display according to the present invention, four sub-pixels R, G, B, and W that are continuously arranged in the horizontal direction are driven by one reference line Vref. DT) mobility is configured to be sensed.

In this configuration, the sensing method of the organic light emitting diode display according to the first embodiment of the present invention senses the current of the driving TFT of the three sub-pixels among the four sub-pixels (R, G, B, W) at the same time Repeatedly, it will be described in more detail with reference to Figures 4A to 4D as follows.

First, when the current of one driving TFT is sensed for each of the subpixels R, G, B, and W, the currents of the driving TFTs of each of the subpixels R, G, B, and W are ir, ig, ib, and iw. ) And the sensing values (VsenR, VsenG, VsenB, VsenW) are shown in Equation 1 below.

Here, t is a sensing time and c is a capacitance of the line capacitor Cref of the reference line REF.

As described above, in the sensing method of the organic light emitting diode display according to the first exemplary embodiment of the present invention, the current of the driving TFTs of the three subpixels among the four subpixels R, G, B, and W is simultaneously sensed. In order to repeat the above, four selections are required to prevent the selected combination from overlapping when selecting three subpixels among the four subpixels R, G, B, and W. FIG.

Accordingly, a case in which three subpixels are selected differently will be described below with reference to FIGS. 4A to 4D.

As shown in FIG. 4A, when the scan signal and the sense signal are high, each data line of the R subpixel R, the G subpixel G, and the B subpixel B is shown. The voltages Vdata R, Vdata G, and Vdata B for sensing the mobility of the driving TFTs are applied, and a voltage of 0V or no voltage is applied to the data line of the W subpixel W (Vblk). As shown in FIG. 3, after a predetermined time, when the current of the driving TFTs of the R, G, and B subpixels R, G, and B is simultaneously sensed through an ADC through a reference line Ref, The sensing value Vsen1 is shown in [Equation 2].

In addition, as shown in FIG. 4B, when the scan signal and the sense signal are high, the R subpixel R, the G subpixel G, and the W subpixel W Voltages Vdata R, Vdata G, and Vdata W for sensing the mobility of the driving TFTs are applied to each data line, and a voltage of 0V or no voltage is applied to the data lines of the B subpixel W ( Vblk). As shown in FIG. 3, after a predetermined time, when a current of the driving TFT of the R, G, and W subpixels R, G, and W is simultaneously sensed through the reference line through the reference line, a sensing value is detected. (Vsen2) is the same as [Equation 3].

As shown in FIG. 4C, when the scan signal and the sense signal are high, each data of the R subpixel R, B subpixel B, and W subpixel W is generated. Voltages Vdata R, Vdata B, and Vdata W for sensing the mobility of the driving TFTs are applied to the line, and a voltage of 0 V is not applied to the data line of the G subpixel G (Vblk). . As shown in FIG. 3, after a predetermined time, when the current of the driving TFTs of the R, B, and W subpixels R, B, and W is simultaneously sensed through the ADC through the reference line ref. , The sensing value (Vsen3) is the same as [Equation 4].

As shown in Fig. 4D, when the scan signal is high, each data line of the G subpixel G, the B subpixel B, and the W subpixel W has a mobility of a driving TFT. Voltages for sensing (Vdata G, Vdata B, and Vdata W) are applied, and a voltage of 0V or no voltage is applied to the data line of the R subpixel R (Vblk). As shown in FIG. 3, after a predetermined time, when a current of the driving TFTs of the G, B, and W subpixels G, B, and W is simultaneously sensed through the reference line through the reference line, a sensing value is sensed. (Vsen4) is the same as [Equation 5].

In this way, three subpixels among four subpixels are selected over four times to simultaneously sense currents of the driving TFTs of the selected three subpixels. In addition, Equation 6 may be obtained by adding Equations 2 to 5, which are the sensing values Vsen1, Vsen2, Vsen3, and Vsen4 sensed over four times.

In addition, multiplying each of Equations 2 to 5 by Equation 7 gives Equations 7 to 10.

Then, by subtracting [Equation 7] from [Equation 6], the current value iw of the driving TFT of the W subpixel W can be obtained as shown in [Equation 11].

In the same manner, by subtracting [Equation 8] from [Equation 6] above, the current value ib of the driving TFT of the B subpixel B can be obtained as shown in [Equation 12].

In the same manner, by subtracting [Equation 9] from [Equation 6] above, the current value ig of the driving TFT of the G subpixel G can be obtained as shown in [Equation 13].

In the same manner, by subtracting [Equation 10] from Equation 6 above, the current value ir of the driving TFT of the R subpixel R can be obtained as shown in Equation 14.

As described above, the circuit is arranged such that the mobility of the driving TFT DT is sensed by one reference signal line Vref such that four subpixels R, G, B, and W arranged in the horizontal direction are sensed. When configured, three subpixels among four subpixels R, G, B, and W are selected, and a voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected three subpixels, After applying a voltage of 0V or no voltage to the data line of the other subpixel, the current of the driving TFTs of the selected three subpixels is sensed simultaneously.

In this way, the selected three sub-pixels are repeatedly selected four times to be different from each other, and the currents of the driving TFTs DT of the three selected sub-pixels are sensed and stored at the same time. The current values are added, and the current value sensed each time is subtracted from the summed current value to calculate the current of the driving TFTs of the respective subpixels.

The gain compensation value of the driving TFTs of the respective sub fill cells is determined.

Meanwhile, as shown in FIGS. 4A to 4D, four subpixels R, G, B, and W that are continuously arranged in the horizontal direction are moved by the driving signal DT by one reference signal line Vref. Even when the circuit is configured to sense the figure, the mobility of the driving TFTs of the plurality of subpixels may be sensed in another manner.

5 is an equivalent circuit diagram illustrating a plurality of subpixel circuits for explaining a sensing method of an organic light emitting diode display according to a second exemplary embodiment of the present invention.

4A to 4D, three subpixels among four subpixels R, G, B, and W are selected, and a voltage for sensing the mobility of the driving TFT in the data lines of the selected three subpixels. After applying and applying a voltage of 0V to the data line of the other sub-pixel or no voltage, the current of the driving TFTs of the three selected sub-pixels is sensed at the same time.

However, in the sensing method of the organic light emitting diode display according to the second exemplary embodiment of the present invention, as shown in FIG. 5, two subpixels among four subpixels R, G, B, and W are selected. In addition, a voltage for sensing the mobility of the driving TFT is applied to the data lines of the two selected sub pixels, and a voltage of 0 V is applied or no voltage is applied to the data lines of the remaining two sub pixels. The current of the driving TFT of the sub pixel can be sensed at the same time.

That is, as shown in FIG. 5, when the scan signal is high, each data line of the R subpixel R and the G subpixel G has a voltage Vdata R for sensing the mobility of the driving TFT. , Vdata G), and a voltage of 0V or no voltage is applied to the data lines of the B subpixel B and the W subpixel W (Vblk). After a certain time, when the current of the driving TFTs of the R and G subpixels are sensed simultaneously through the ADC through the reference line, the sensing value Vsen1 can be obtained as shown in [Equation 15].

Although the above-described process is repeated, although not shown in the drawings, voltages Vdata R and Vdata B for sensing the mobility of the driving TFT are provided in each of the data lines of the R subpixel R and the B subpixel B. FIG. Is applied to the data lines of the G subpixel B and the W subpixel W, or a voltage of 0 V is not applied (Vblk). After a certain time, when the current of the driving TFTs of the R and B subpixels R and B is simultaneously sensed through the ADC through the reference line, the sensing value Vsen2 may be obtained as shown in Equation 16 below.

In addition, voltages Vdata R and Vdata W for sensing the mobility of the driving TFTs are applied to each data line of the R subpixel R and the W subpixel W, and the G subpixel G and B A voltage of 0V or no voltage is applied to the data line of the subpixel B (Vblk). After a predetermined time, when the current of the driving TFTs of the R and W subpixels R and W is simultaneously sensed through the ADC through the reference line, the sensing value Vsen3 may be obtained as shown in Equation 17.

In addition, voltages Vdata G and Vdata B for sensing the mobility of the driving TFTs are applied to each data line of the G subpixel G and the B subpixel B, and the R subpixels R and W are applied. A voltage of 0V or no voltage is applied to the data line of the subpixel W (Vblk). After a predetermined time, when the current of the driving TFTs of the G and B subpixels G and B is simultaneously sensed through the ADC through the reference line, the sensing value Vsen4 may be obtained as shown in Equation 18.

In addition, voltages Vdata G and Vdata W for sensing the mobility of the driving TFT are applied to each data line of the G subpixel G and the W subpixel W, and the R subpixels R and B A voltage of 0V or no voltage is applied to the data line of the subpixel B (Vblk). After a certain time, when the current of the driving TFTs of the G and W subpixels G and W is simultaneously sensed through the ADC through the reference line, the sensing value Vsen5 may be obtained as shown in Equation 19.

In addition, voltages Vdata B and Vdata W for sensing the mobility of the driving TFTs are applied to the data lines of the B subpixel B and the W subpixel W, and the R subpixels R and G are applied. A voltage of 0V or no voltage is applied to the data line of the subpixel G (Vblk). After a certain time, when the current of the driving TFTs of the B and W subpixels B and W is simultaneously sensed through the ADC through the reference line, the sensing value Vsen6 may be obtained as shown in Equation 20.

Then, the sum of Equation 15 to Equation 20 is as follows.

In addition, when [Equation 15], [Equation 16] and [Equation 18] is summed, Equation 22 is obtained.

In addition, when [Equation 15], [Equation 17] and [Equation 19] is summed, Equation 23 is as follows.

In addition, when [Equation 16], [Equation 17] and [Equation 20] is summed, Equation 24 is as follows.

In addition, when [Equation 18], [Equation 19] and [Equation 20] is summed, Equation 25 is as follows.

Then, by subtracting [Equation 22] from [Equation 21], the current value iw of the driving TFT of the W subpixel W can be obtained as shown in [Equation 26].

In addition, by subtracting [Equation 23] from [Equation 21], the current value ib of the driving TFT of the B subpixel B can be obtained as shown in [Equation 27].

In addition, by subtracting [Equation 24] from Equation 21, the current value ig of the driving TFT of the G subpixel G can be obtained as shown in Equation 28.

In addition, by subtracting [Equation 25] from Equation 21, the current value ir of the driving TFT of the R subpixel R can be obtained as shown in Equation 29.

In this manner, two subpixels of the four subpixels R, G, B, and W are selected, and a voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected two subpixels. The voltage of 0V is not applied to the data lines of the remaining two sub pixels.

In this case, the selected two subpixels are repeatedly selected six times to be different from each other, and the currents of the driving TFTs DT of the two selected subpixels are simultaneously sensed and stored, and the current value sensed by the sixth time is sensed. And adding the currents sensed by 3 out of 6 to not overlap each other, overturning the addition 4 times, and adding the current values sensed by 6 to the above value. The current of the driving TFTs of the subpixels may be calculated by subtracting the sum of the current sensed by step 3.

The gain compensation value of the driving TFTs of the respective sub fill cells is determined.

Meanwhile, in FIGS. 4A to 4D and 5, four sub-pixels R, G, B, and W arranged in a horizontal direction in succession are moved by the reference signal line Vref. Although the circuit of the OLED display is configured to be sensed, the present invention is not limited thereto.

That is, even when the circuit of the OLED display device is configured such that the mobility of the driving TFT DT is sensed by one reference signal line Vref such that three or five or more subpixels continuously arranged in the horizontal direction are sensed. The sensing method of the organic light emitting diode display of the present invention can be applied.

6A through 6C are equivalent circuit diagrams illustrating a plurality of subpixel circuits for describing a sensing method of an organic light emitting diode display according to a third exemplary embodiment of the present invention.

6A to 6C, an OLED display in which three subpixels R, G, and B arranged in a horizontal direction are sensed by one reference signal line Vref such that the mobility of the driving TFT DT is sensed. Circuit diagram of the device.

In the sensing method of the organic light emitting diode display according to the third exemplary embodiment of the present invention, the current of the driving TFTs of the two subpixels among the three subpixels R, G, and B is simultaneously sensed. Three selections are required in order to prevent the selected combination from overlapping when selecting two subpixels among the R subpixels R, G, and B.

Accordingly, a case in which two subpixels are selected differently will be described below with reference to FIGS. 6A to 6C.

As shown in FIG. 6A, when the scan signal is high, voltages Vdata R and Vdata for sensing the mobility of the driving TFT are applied to each data line of the R subpixel R and the G subpixel G. FIG. G) is applied and a voltage of 0V is not applied to the data line of the B subpixel B (Vblk). After a predetermined time, when the current of the driving TFTs of the R and G subpixels R and G is simultaneously sensed through the ADC through the reference line, the sensing value Vsen1 is expressed by Equation 30.

In addition, as shown in FIG. 6B, when the scan signal is high, each data line of the R subpixel R and the B subpixel B has a voltage Vdata R for sensing the mobility of the driving TFT. , Vdata B), and a voltage of 0V or no voltage is applied to the data line of the G subpixel G (Vblk). After a certain time, when the current of the driving TFTs of the R and B subpixels R and B is simultaneously sensed through the ADC through the reference line, the sensing value Vsen2 is expressed by Equation 31.

In addition, as shown in FIG. 6C, when the scan signal is high, each data line of the G subpixel G and the B subpixel B has a voltage Vdata G for sensing the mobility of the driving TFT. , Vdata B) is applied and a voltage of 0V is not applied to the data line of the R subpixel R (Vblk). After a predetermined time, when the current of the driving TFTs of the G and B sub pixels G and B is simultaneously sensed through the reference line through the reference line, the sensing value Vsen3 is expressed by Equation 32.

Equation 30 can be obtained by summing the above Equations 30 to 32.

Then, multiplying each of Equation 30 to Equation 32 by 2 yields Equations 34 to 36.

Then, by subtracting [34] from [33], the current value ib of the driving TFT of the B subpixel B can be obtained as shown in [37].

In the same manner, by subtracting Equation 35 from Equation 33, the current value ig of the driving TFT of the G subpixel GB can be obtained as shown in Equation 38.

In the same manner, by subtracting [Equation 36] from [Equation 33], the current value ir of the driving TFT of the R sub pixel R can be obtained as shown in [Equation 39].

As described above, a circuit may be configured such that the mobility of the driving TFT DT is sensed by one reference signal line Vref such that three subpixels R, G, and B arranged in a horizontal direction are arranged in succession. In this case, two subpixels of the three subpixels R, G, and B are selected, and the selected two subpixels are repeatedly selected three times so that the combination of the selected two subpixels is different from each other. A voltage for sensing the mobility of the driving TFT is applied, and no voltage is applied to the data line of the other subpixel.

In this manner, three times are selected, the currents of the driving TFTs DT of the two selected sub-pixels are sensed and stored at the same time, the current values sensed by the three times are summed, and each time is sensed from the summed current values. The current value of the driving TFT of each subpixel is calculated by subtracting the current value.

The gain compensation value of the driving TFTs of the respective sub fill cells is determined.

Meanwhile, in FIGS. 4A to 4D, 5, and 6A to 6C, three or four sub pixels arranged in a horizontal direction are sensed by one reference signal line Vref to sense the mobility of the driving TFT DT. Although the circuit configured to be described above has been described, the present invention is not limited thereto, and the circuit configured to sense the mobility of the driving TFT DT by one reference signal line Vref is arranged in five or more subpixels arranged in a horizontal direction. The features of the invention can be applied.

For example, when five sub pixels arranged in a horizontal direction are configured to sense the mobility of the driving TFT DT by one reference signal line Vref, as described with reference to FIGS. 4A to 4D, Four subpixels of the five subpixels are selected, a voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected four subpixels, and a voltage of 0 V is applied to the data line of the other subpixel. After applying or not applying a voltage, the current of the driving TFT DT of the selected four sub-pixels is simultaneously sensed.

This process is selected five times so that the combination of the four subpixels are different from each other to simultaneously sense the current of the driving TFT DT of the selected four subpixels.

The sub-cells calculated by calculating the current values of the driving TFTs of the sub-pixels by summing the current sensed current values of the four sub-pixels in total and subtracting the sensed current values from the summed-up current values each time. Determine the gain compensation value of the driving TFT of these.

Of course, even when the five sub pixels arranged in the horizontal direction are configured to sense the mobility of the driving TFT DT by one reference signal line Vref, as described with reference to FIG. 5, the five sub pixels. Select three subpixels, apply a voltage for sensing the mobility of the driving TFT to the data lines of the selected three subpixels, and apply a voltage of 0V to the data lines of the remaining two subpixels. After not applying, the current of the driving TFT DT of the selected three sub pixels may be sensed at the same time, and the current value of the driving TFT of each sub pixel may be calculated through a calculation process. However, it is inefficient than selecting four of the five sub pixels.

Therefore, when m subpixels arranged in a horizontal direction are configured to sense the mobility of the driving TFT DT by one reference signal line Vref, (m-1) of m subpixels The subpixels are selected, a voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected (m-1) subpixels, and a voltage of 0V is applied or the voltage is applied to the data lines of the other subpixels. After not applying, the current of the driving TFT DT of the selected (m-1) sub-pixels is simultaneously sensed. Where m is a natural number equal to or greater than 3.

In this process, m combinations of (m-1) subpixels are selected a total of m times to sense currents of the driving TFTs DT of the selected (m-1) subpixels simultaneously.

Then, m simultaneous sensed current values are added and subtracted each time from the summed current value to calculate the current value of the driving TFT of each sub-pixel, and thus the gain compensation of the driving TFT of each sub-pillar cell is calculated. Determine the value.

As described above, the sensing method of the OLED display device according to the exemplary embodiment of the present invention has the following effects.

7 is a graph illustrating a sensing time comparison according to a sensing method of an OLED display device of the present invention.

As shown in FIG. 7, when sensing the current of the driving TFT of one sub-pixel, the sensed current is low, and thus the sensing period needs to be lengthened, so that time is insufficient for sensing the current of the driving TFT within the blank period.

However, since the current of the driving TFTs of the at least two sub pixels is sensed simultaneously as in the present invention, the sensed current is high, so that the current of the driving TFTs can be sufficiently sensed within the blank period without lengthening the sensing period. Therefore, sensing noise due to lack of sensing time can be reduced.

In addition, when the currents of the driving TFTs of the at least two subpixels are sensed at the same time, the sensed current is high, so that the sensing period can be relatively shortened, thereby reducing the sensing time.

The above description is merely illustrative of the present invention, and various modifications may be made by those skilled in the art without departing from the technical spirit of the present invention. Therefore, the embodiments disclosed in the specification of the present invention are not intended to limit the present invention. The scope of the present invention should be construed by the claims below, and all techniques within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: panel 200: gate driver
300: data driver 400: timing controller
500: memory 600: power supply

Claims (11)

A sensing method of an organic light emitting diode display device, wherein m subpixels arranged in a horizontal direction are sensed so that mobility of a driving TFT is sensed by one reference signal line.
selecting (m-1) subpixels of the m subpixels, wherein m combinations are selected so that the combination of the selected (m-1) subpixels does not overlap, where m is a natural number of 3 or more;
Simultaneously sensing current of the driving TFTs of the selected (m-1) sub-pixels of each combination;
Summing the sensed currents of the m combinations; And
And calculating the current of the driving TFT of each sub-pixel by subtracting the sensed current value of each combination from the sum of the sensed current values. The method according to claim 1,
A voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected (m-1) subpixels, and a voltage of 0V or no voltage is applied to the data lines of the other subpixels. A sensing method of an organic LED display device. Selecting three subpixels among four subpixels sequentially arranged in the horizontal direction, and selecting a combination of four such that the combination of the selected three subpixels does not overlap;
Simultaneously sensing currents of the driving TFTs of the selected three sub-pixels of each combination;
Summing the sensed currents of the four combinations; And
And calculating the current of the driving TFT of each sub-pixel by subtracting the sensed current value of each combination from the sum of the sensed current values. The method according to claim 3,
A voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected three subpixels, and a voltage of 0V is applied or no voltage is applied to the data lines of the other subpixels. Sensing method of LED display device. The method according to claim 3,
Said four subpixels having R, G, B and W subpixels, said four combinations comprising a first combination of selecting R, G and B subpixels, a second combination of selecting R, G and W subpixels, A third combination of selecting R, B, and W subpixels, and a fourth combination of selecting G, B, and W subpixels,
Simultaneously sensing currents of the driving TFTs of the selected sub-pixels of each combination to calculate respective sensing values Vsen1, Vsen2, Vsen3, and Vsen4 of the first to fourth combinations,
The current (ir, ig, ib, iw) of the driving TFT of each sub pixel is calculated by the following Equation.

Selecting two subpixels among four subpixels sequentially arranged in the horizontal direction, and selecting a combination of six so that the combination of the selected two subpixels does not overlap;
Simultaneously sensing current of the driving TFTs of the selected two sub-pixels of each combination;
Summing the six combinations of sensed currents; And
Selecting and summing three combinations of sensed currents among the six combinations of sensed currents to calculate four sets of summing currents so that the sensed currents of the three subpixels do not overlap;
And calculating the current of the driving TFT of each sub-pixel by subtracting each set of sum currents from the sum of the sum values of the six combinations. The method according to claim 6,
A voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected two subpixels, and a voltage of 0V is applied or no voltage is applied to the data lines of the remaining two subpixels. Sensing method of LED display device. The method according to claim 6,
The four subpixels have R, G, B and W subpixels, and the six combinations comprise a first combination of R and G subpixels, a second combination of R and B subpixels, and a R and W subpixel. The pixels have a third combination selected, a fourth combination selected G and B sub pixels, a fifth combination selected G and W sub pixels, and a sixth combination selected B and W sub pixels,
Simultaneously sensing currents of the driving TFTs of the selected sub-pixels of each combination to calculate respective sensing values Vsen1, Vsen2, Vsen3, Vsen4, Vsen5, and Vsen6 of the first to sixth combinations,
The current (ir, ig, ib, iw) of the driving TFT of each sub pixel is calculated by the following Equation.

Selecting two subpixels of three subpixels sequentially arranged in a horizontal direction, and selecting a combination of three so that the combination of the selected two subpixels does not overlap;
Simultaneously sensing current of the driving TFTs of the selected two sub-pixels of each combination;
Summing the three combined sensed currents; And
And calculating the current of the driving TFT of each sub-pixel by subtracting the sensed current value of each combination from the sum of the sensed current values. The method according to claim 9,
A voltage for sensing the mobility of the driving TFT is applied to the data lines of the selected two subpixels, and a voltage of 0V is applied or no voltage is applied to the data lines of the other subpixels. Sensing method of LED display device. The method according to claim 9,
Wherein the three subpixels have R, G and B subpixels, the three combinations comprise a first combination of selecting R and G and B subpixels, a second combination of selecting R and B subpixels, and G and B A third combination of selecting subpixels,
Simultaneously sensing the currents of the driving TFTs of the selected sub-pixels of each combination to calculate respective sensing values Vsen1, Vsen2, and Vsen3 of the first to third combinations,
The current (ir, ig, ib) of the driving TFT of each sub pixel is calculated by the following Equation.

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