JP7469220B2 - Light-emitting display device and method for driving the same - Google Patents

Description

The present invention relates to a light-emitting display device and a method for driving a light-emitting display device.

In recent years, there has been a demand for light-emitting display devices capable of providing stable, high-quality displays.
In conventional light-emitting display devices, it is difficult to provide a stable, high-quality display due to degradation of the elements.

Patent Document 1, which is an example of the conventional technology, discloses a technology for sensing the deterioration of an OLED element.
In the technology disclosed in Patent Document 1, in an OLED pixel in which a plurality of sub-pixels share a single reference voltage line and a scan TFT (Thin Film Transistor) and a sensing TFT are connected to a common gate line, degradation of the OLED element of a selected sub-pixel is sensed.

Korean Patent Publication No. 10-2017-0021406

However, with the above-mentioned conventional technology, the sensing value fluctuates with the change in threshold voltage caused by degradation of the sensing TFT, making it difficult to accurately sense the degradation of the OLED element.

In view of the above, the present invention aims to provide a technology for accurately sensing the deterioration of OLED elements.

One aspect of the present invention that solves the above-mentioned problems and achieves the object is a method for driving a light-emitting display device having a plurality of sub-pixels, each of which is provided with a scan TFT, a sensing TFT, and a drive TFT, the gates of the scan TFT and the sensing TFT are connected to a common scan line, and the source or drain of the sensing TFT is connected to a reference voltage supply and a sensing detection line common to other sub-pixels, and the method includes turning on one drive TFT of the plurality of sub-pixels that share the reference voltage supply and sensing detection line, and maintaining the drive TFTs of the other sub-pixels in an off state, setting the voltage of the scan line lower than the gate voltage of the one drive TFT that is turned on and higher than the voltage of the cathode of the light-emitting element, and sensing the threshold voltage of the sensing TFT with the reference voltage supply and sensing detection line.

In the above configuration, the compensation value of the light-emitting element is calculated using the threshold voltage of the sensing TFT, and the compensation value of the light-emitting element is used to compensate for degradation of the light-emitting element, thereby making it possible to compensate for degradation of the light-emitting element.

The method for driving a light-emitting display device having the above-described configuration further includes compensating for degradation of the pixel by compensating for degradation of the other sub-pixels, and sequentially compensating for degradation of the pixels arranged in a matrix by sequentially compensating for degradation of the pixels, thereby making it possible to compensate for degradation of the light-emitting display device.

Alternatively, one aspect of the present invention is a light-emitting display device that includes a panel including a normal drive and a sensing drive; and at least three sub-pixels in the panel that emit different colors, each of the at least three sub-pixels including a pixel circuit and a light-emitting element, and in the sensing drive, one of the at least three sub-pixels is applied with a higher data voltage than the other sub-pixels.

In the light-emitting display device having the above configuration, the sensing drive may be performed during a power-off sequence period.

In the light-emitting display device having the above configuration, the sensing drive may include an initialization period, a light-emitting period, and a sensing period.

In the light-emitting display device having the above configuration, during the initialization period, a data voltage that turns on the driving TFT of one of the sub-pixels is applied, and a data voltage of 0 V is applied to the other sub-pixels.

In the light-emitting display device having the above configuration, during the light-emitting period, the light-emitting element of one of the sub-pixels may be made to emit light, and the light-emitting element of the other sub-pixel may be made not to emit light.

The light-emitting display device having the above configuration may further include a reference voltage supply and sensing detection line electrically connected to the at least three sub-pixels, and a voltage of 0 V may be applied to the reference voltage supply and sensing detection line during the light-emitting period.

The present invention makes it possible to accurately sense the deterioration of OLED elements.

FIG. 1 is a block diagram showing an overall configuration of a light emitting display device according to an embodiment. FIG. 2 is a diagram showing a pixel circuit of a pixel. FIG. 3 is a flowchart showing the operation of compensating for deterioration of the light emitting display device shown in FIG. FIG. 4A is a flowchart showing the correction of the compensation value of the OLED element to which the above-mentioned technique is applied, and FIG. 4B is a flowchart showing the display operation of image data using the corrected compensation value. FIG. 5 is a timing chart of steps S21 to S23 in FIG. 6A is a diagram showing the change over time of the detection voltage when the threshold voltage change of the transistor is ΔVth=0 V during the sensing period, and FIG. 6B is a diagram showing the change over time of the detection voltage when the threshold voltage change of the transistor is ΔVth=1 V during the sensing period. FIG. 7 is a diagram showing the operation of the sub-pixels and the sensing units in the initialization period. FIG. 8 is a diagram showing the operation of the sub-pixels and the sensing units during the light emission period. FIG. 9 is a diagram showing the operation of the sub-pixels and the sensing units during the sensing period.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
However, the present invention should not be construed as being limited to the following embodiments.

<Embodiment>
FIG. 1 is a block diagram showing the overall configuration of a light-emitting display device 100 according to the present embodiment.
The light emitting display device 100 shown in FIG. 1 includes a timing controller 110, a data line driving circuit 120, a gate line driving circuit 130, a memory unit 140, and a plurality of pixels 200 arranged in a matrix (m rows x n columns).
The pixel 200 includes a sub-pixel 200R, a sub-pixel 200W, a sub-pixel 200B, and a sub-pixel 200G.
In addition, the light emitting display device 100 is supplied with a low potential voltage VSS.
An example of the low potential voltage VSS is the ground voltage (=0 V).

The timing controller 110 drives the data line driving circuit 120 and the gate line driving circuit 130 by outputting control signals to them based on the timing synchronization signal TSS and the data current Idata.
Here, the timing synchronization signal TSS includes a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a clock signal, and the like.

The data line driving circuit 120 is a driving circuit that outputs signals to the connected data signal lines DataR, DataW, DataB, and DataG to drive them based on control signals from the timing controller 110, and supplies a reference voltage Vref to the reference voltage supply and sensing detection line Ref.
In addition, the data line driving circuit 120 supplies a reference voltage and detects the voltage of the sensing detection line Ref during sensing.

The gate line driving circuit 130 is a driving circuit that outputs a signal to the scan signal line Scan to drive it based on a control signal from the timing controller 110, and supplies a high potential voltage VDD to the high potential voltage line Vdd.

The memory unit 140 stores at least the degradation data for each subpixel or the average of all subpixels in the panel.

In addition, the light-emitting display device 100 has sub-pixels SP(R), SP(W), SP(G) and SP(B) defined by data signal lines DataR, DataW, DataG, DataB, a reference voltage supply and sensing detection line Ref, a high potential voltage line Vdd and a scan signal line Scan, which are arranged in a matrix.
Each of the sub-pixels 200 includes a light-emitting element and a pixel circuit for causing the light-emitting element to emit light.
The light emitting element emits light in response to a current flowing from a high potential voltage line Vdd of a high potential voltage VDD to a low potential voltage line Vss of a low potential voltage VSS via a drive transistor included in a pixel circuit.

The sub-pixels may operate differently during normal driving for image display and during sensing driving for degradation sensing.
The sensing drive is a drive for sensing the deterioration of the OLED element.
The sensing drive can be performed during a vertical blank period during image display, during a power-on sequence period before the start of image display, or during a power-off sequence period after the end of image display.
The vertical blanking period is a period during which image data is not written, and is disposed in each vertical active section during which one frame's worth of image data is written.
The power-on sequence period is the period from when the driving power supply is turned on until an image is displayed.
The power-off sequence period is a period from the end of image display in response to reception of an off signal by the light-emitting display device until the driving power supply is turned off.

FIG. 2 is a diagram showing a pixel circuit of the pixel 200.
The pixel 200 shown in FIG. 2 includes a sub-pixel 200R, a sub-pixel 200W, a sub-pixel 200B, and a sub-pixel 200G.

The sub-pixel 200R includes transistors 201R, 202R, and 203R, which are N-type TFTs, a capacitance element 204R, and a light-emitting element 205R.
Here, the transistor 201R is a scan TFT, the transistor 202R is a drive TFT, and the transistor 203R is a sensing TFT.
Furthermore, the capacitive element 204R is a storage capacitor.

The light emitting element 205R includes an anode connected to the drive transistor, a cathode connected to the low potential voltage line Vss, and a light emitting layer between the anode and cathode, and emits red light.
The light-emitting layer includes an electron injection layer, an electron transport layer, an organic light-emitting layer, a hole transport layer, and a hole injection layer, which are stacked in this order between a cathode and an anode.
In light-emitting element 205R, when a positive bias is applied between the anode and 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 supplied to the organic light-emitting layer via the hole injection layer and the hole transport layer.
In the organic light-emitting layer, the supplied electrons and holes recombine to cause a fluorescent or phosphorescent substance to emit light with a luminance proportional to the current density.
On the other hand, when a negative bias is applied to the light emitting element 205R, it functions as a capacitive element that accumulates electric charges.

FIG. 2 also shows a reference voltage supply and sensing detection line Ref, data signal lines DataR, DataW, DataB, and DataG, a scan signal line Scan, a high potential voltage line Vdd, and a low potential voltage line Vss.
As shown in FIG. 2, in pixel 200, the reference voltage supply and sensing detection line Ref and the scan signal line Scan are shared among sub-pixels 200R, 200W, 200B, and 200G, and data signal lines DataR, DataW, DataB, and DataG are provided corresponding to each of the sub-pixels 200R, 200W, 200B, and 200G.

A high-potential voltage line Vdd that supplies a high-potential voltage VDD and a low-potential voltage line Vss that supplies a low-potential voltage VSS that is lower than the high-potential voltage VDD are each set to a fixed potential.
The reference voltage supply and sensing detection line Ref supplies a reference voltage Vref that is lower than the high potential voltage VDD and greater than or equal to the low potential voltage VSS.
That is, VDD>Vref>VSS.

In addition, the sub-pixel 200R includes a first node N1R and a second node N2R.
The first node N1R is connected to one of the source and drain of the transistor 201R, the gate of the transistor 202R, and one electrode of the capacitor 204R.
The second node N2R is connected to one of the source and drain of the transistor 202R, one of the source and drain of the transistor 203R, the other electrode of the capacitor 204R, and the anode of the light-emitting element 205R.

The gate of the transistor 201R is connected to the scan signal line Scan, one of the source and drain is connected to the first node N1R, and the other of the source and drain is connected to the data signal line DataR.
The gate of the transistor 202R is connected to a first node N1R, one of the source and drain is connected to a second node N2R, and the other of the source and drain is connected to the high potential voltage line Vdd.
The gate of the transistor 203R is connected to the scan signal line Scan, one of the source and drain is connected to the second node N2R, and the other of the source and drain is connected to the reference voltage supply and sensing detection line Ref.
One electrode of the capacitance element 204R is connected to a first node N1R, and the other electrode is connected to a second node N2R.
The anode of the light-emitting element 205R is connected to the second node N2R, and the cathode is connected to the low potential voltage line Vss.

The sub-pixels 200W, 200B, and 200G have the same configuration as the sub-pixel 200R.
The sub-pixel 200W includes transistors 201W, 202W, and 203W, which are N-type thin film transistors (TFTs), a capacitance element 204W, and a light-emitting element 205W.
The sub-pixel 200B includes transistors 201B, 202B, and 203B, which are N-type thin film transistors (TFTs), a capacitance element 204B, and a light-emitting element 205B.
The sub-pixel 200G includes transistors 201G, 202G, and 203G, which are N-type thin film transistors (TFTs), a capacitance element 204G, and a light-emitting element 205G.
Here, the transistors 201W, 201B, and 201G are scan TFTs, the transistors 202W, 202B, and 202G are drive TFTs, and the transistors 203W, 203B, and 203G are sensing TFTs.
Moreover, the capacitive elements 204W, 204B, and 204G are storage capacitors.
The light emitting elements 205W, 205B, and 205G each include an anode connected to the drive transistor, a cathode connected to the low potential voltage line Vss, and a light emitting layer between the anode and the cathode.
Light emitting element 205W emits white light, light emitting element 205G emits green light, and light emitting element 205B emits blue light.

The sub-pixel 200W includes a first node N1W and a second node N2W.
The first node N1W is connected to one of the source and drain of the transistor 201W, the gate of the transistor 202W, and one electrode of the capacitor 204W.
The second node N2W is connected to one of the source and drain of the transistor 202W, one of the source and drain of the transistor 203W, the other electrode of the capacitor 204W, and the anode of the light-emitting element 205W.

The gate of transistor 201W is connected to the scan signal line Scan, one of the source and drain is connected to the first node N1W, and the other of the source and drain is connected to the data signal line DataW.

The gate of transistor 202W is connected to a first node N1W, one of the source and drain is connected to a second node N2W, and the other of the source and drain is connected to a high potential voltage line Vdd.

The gate of transistor 203W is connected to the scan signal line Scan, one of the source drains is connected to the second node N2W, and the other of the source drains is connected to the reference voltage supply and sensing detection line Ref.

One electrode of the capacitance element 204W is connected to the first node N1W, and the other electrode is connected to the second node N2W.

The anode of the light-emitting element 205W is connected to the second node N2W, and the cathode is connected to the low-potential voltage line Vss.

The sub-pixel 200B includes a first node N1B and a second node N2B.
The first node N1B is connected to one of the source and drain of the transistor 201B, the gate of the transistor 202B, and one electrode of the capacitor 204B.
The second node N2B is connected to one of the source and drain of the transistor 202B, one of the source and drain of the transistor 203B, the other electrode of the capacitor 204B, and the anode of the light-emitting element 205B.

The gate of transistor 201B is connected to the scan signal line Scan, one of the source drains is connected to the first node N1B, and the other of the source drains is connected to the data signal line DataB.

The gate of transistor 202B is connected to a first node N1B, one of the source and drain is connected to a second node N2B, and the other of the source and drain is connected to a high potential voltage line Vdd.

The gate of transistor 203B is connected to the scan signal line Scan, one of the source drains is connected to the second node N2B, and the other of the source drains is connected to the reference voltage supply and sensing detection line Ref.

One electrode of the capacitance element 204B is connected to the first node N1B, and the other electrode is connected to the second node N2B.

The anode of light-emitting element 205B is connected to the second node N2B, and the cathode is connected to the low potential voltage line Vss.

The sub-pixel 200G includes a first node N1G and a second node N2G.
The first node N1G is connected to one of a source and a drain of the transistor 201G, the gate of the transistor 202G, and one electrode of the capacitor 204G.
The second node N2G is connected to one of a source and a drain of the transistor 202G, one of a source and a drain of the transistor 203G, the other electrode of the capacitor 204G, and the anode of the light-emitting element 205G.

The gate of transistor 201G is connected to the scan signal line Scan, one of the source and drain is connected to the first node N1G, and the other of the source and drain is connected to the data signal line DataG.

The gate of transistor 202G is connected to a first node N1G, one of the source and drain is connected to a second node N2G, and the other of the source and drain is connected to a high potential voltage line Vdd.

The gate of transistor 203G is connected to the scan signal line Scan, one of the source drains is connected to the second node N2G, and the other of the source drains is connected to the reference voltage supply and sensing detection line Ref.

One electrode of the capacitance element 204G is connected to the first node N1G, and the other electrode is connected to the second node N2G.

The anode of the light-emitting element 205G is connected to the second node N2G, and the cathode is connected to the low-potential voltage line Vss.

Next, the operation of the deterioration compensation will be described.
FIG. 3 is a flowchart illustrating a degradation sensing operation of the light emitting display device 100 shown in FIG.
Degradation compensation for the light-emitting display device 100 shown in FIG. 1 is performed by sensing degradation of sub-pixel 200W (S1), sensing degradation of sub-pixel 200R (S2), sensing degradation of sub-pixel 200B (S3), and sensing degradation of sub-pixel 200G (S4), and repeating these steps until all pixels are completed.
The order of steps S1 to S4 may be interchanged.
Next, a compensation value is calculated from the sensed value, the compensation value is corrected, and when displaying, data voltages are output to the data signal lines DataR, DataW, DataB, and DataG according to the corrected compensation value.

FIG. 4A is a flowchart showing the correction of the compensation value of the OLED element to which the above-mentioned technique is applied, and FIG. 4B is a flowchart showing the display operation of image data using the corrected compensation value.
First, the subpixel is initialized (S21), the light-emitting element of the subpixel is caused to emit light (S22), the threshold voltage of the sensing TFT is sensed by detecting the voltage of the second node in the subpixel (S23), and the compensation value is modified based on the sensing result in S23 (S24).
In this way, a corrected OLED compensation value is obtained.
When displaying image data, image data is input (S31), OLED compensation is performed using the compensation value corrected in S24 for the input image data (S32), and a data line voltage is output based on the compensated value (S33).

Next, steps S21 to S23 in the flow chart shown in FIG. 4A will be described with reference to a timing chart.
FIG. 5 is a timing chart of steps S21 to S23 in FIG.
The pixel circuit shown in FIG. 2 is driven in sequence during an initialization period, a light emission period, and a sensing period, as shown in FIG.
Here, the description focuses on the sub-pixel 200W.

FIG. 7 is a diagram illustrating the operations of the sub-pixels 200W, 200R, 200B, and 200G and the sensing unit 300 during the initialization period.
FIG. 8 is a diagram showing the operations of the sub-pixels 200W, 200R, 200B, and 200G and the sensing unit 300 during the light emission period.
FIG. 9 is a diagram showing the operation of the sub-pixels 200W, 200R, 200B, and 200G and the sensing unit 300 during the sensing period.

The sensing unit 300 includes a first switch 301, a second switch 302, and an ADC (analog-to-digital converter) 303, and is provided in the data line driving circuit 102, for example.
When the first sensing switch 301 is turned on, the reference voltage supply and sensing detection line Ref is configured to have the reference voltage Vref.
When the second sensing switch 302 is turned on, the reference voltage supply and sensing detection line Ref is configured to be connected to the ADC 303 .
The ADC 303 converts the detected analog sensing voltage into a digital sensing value and transmits it to the timing controller 110 .

<Initialization period>
During the initialization period, the data signal lines DataR, DataG, and DataB are set to, for example, 0 V, the data signal line DataW is set to, for example, 6 V, and the scan signal line Scan is set to, for example, 22 V so that the transistors 201R, 201W, 201B, 201G, 203R, 203W, 203B, and 203G are turned on.
Here, 6V of the data signal line DataW is a voltage for turning on the driving TFT of the subpixel 200W on the data signal line DataW, and may be a voltage for compensating for deviation in electrical characteristics of the driving TFT in normal driving.
As a result, the transistors 202R, 202B, and 202G are turned off, and the transistor 202W is turned on.

As shown in FIG. 7, in the initialization period, the scan signal line Scan is set to, for example, 22 V, which turns on the transistors 201W and 203W included in the sub-pixel 200W to be sensed.
During the initialization period, the first sensing switch 301 is turned on and the second sensing switch 302 is turned off.
The first node N1W is a voltage obtained by dropping the voltage 6V of the data line DataW through the transistor 201W, and is charged to, for example, 5V.

<Light Emitting Period>
During the light emission period, the scan signal line Scan is set to, for example, -6 V to turn off 201R, 201W, 201B, 201G, 203R, 203W, 203B, and 203G.
Since the first nodes N1R, N1B, and N1G are at 0V, the transistors 202R, 202B, and 202G are turned off.
Here, the data signal lines DataR, DataB, and DataG are in a state of 0V, and the data signal line DataW is set to, for example, 16V.
Since the voltage of the first node N1W is 5V, the transistor 202W is turned on, and a current flows from the high potential voltage line Vdd to the second node N2R.
This causes the voltage at the anode of the light emitting element 205W to rise, causing the light emitting element 205W to emit light.
At this time, the light emission is barely noticeable to the viewer because the light emission luminance is low and the light emission time is very short.

As shown in FIG. 8, during the light emission period, the scan signal line Scan is set to, for example, −6 V, which turns off the transistors 201W and 203W included in the sub-pixel 200W to be sensed.
During the light emission period, the first sensing switch 301 maintains the ON state, and the second sensing switch 302 maintains the OFF state.
Since the gate of the transistor 202W is charged to 5 W during the initialization period, the transistor 202W turns on and the light emitting element 205 emits light.

<Sensing period>
During the sensing period, the voltage of the scan signal line Scan is set to, for example, 4V, lower than the gate voltage of the transistor 202W (for example, 5V) and higher than the cathode voltage of the light-emitting element (for example, 0V).
The data signal lines DataR, DataB, and DataG are maintained at 0V.
When the reference voltage supply and sensing detection line Ref is in a floating state, a current flows from the second node N2R to the reference voltage supply and sensing detection line Ref.
The voltage of the reference voltage supply and sensing detection line Ref rises to a value obtained by subtracting the threshold voltage of the transistor 203W from the voltage of the scan signal line Scan (4V), that is, 3V if the threshold voltage of the transistor 203W is 1V.

9, during the sensing period, the scan signal line Scan is set to a voltage lower than the gate voltage of the transistor 202W (for example, 5 V) and higher than the voltage of the cathode of the light-emitting element (for example, 0 V). Here, it is set to 4 V, for example.
During the sensing period, the first sensing switch 301 is turned off, and the second sensing switch 302 maintains the off state.
As a result, the reference voltage supply and sensing detection line Ref is in a floating state,
Since the transistor 203W is on, the voltage of the reference voltage supply and sensing detection line Ref rises to a value obtained by subtracting the threshold voltage of the transistor 203W from the voltage of the scan signal line Scan, 4V.
When the second sensing switch 302 is turned on, the voltage of the line capacitor LCa of the reference voltage supply and sensing detection line Ref is sampled by the ADC 303 as a sensing voltage.

Figure 6 (A) is a diagram showing the change over time of the detection voltage during the sensing period when the initial threshold voltage Vth of transistor 203W is 0.5 V and the threshold voltage change ΔVth is 0 V, and Figure 6 (B) is a diagram showing the change over time of the detection voltage during the sensing period when the threshold voltage change ΔVth of transistor 203W is 1 V.
6A and 6B, the horizontal axis represents time, and the vertical axis represents the reference voltage supply and the detection voltage which is the sensing value on the sensing detection line Ref.
Comparing the detected voltages in FIGS. 6(A) and (B), the detected voltage rises more steeply in FIG. 6(A) than in FIG. 6(B).
Furthermore, when comparing the reference voltage supply and the detection voltage on the sensing detection line Ref at the same time, for example 6 ms, with the start of the sensing period in Figures 6 (A) and (B) set to 0, the detection voltage in Figure 6 (A) is 3.4121 V, and the detection voltage in Figure 6 (B) is 2.4376 V.
As shown in FIGS. 6A and 6B, when the threshold voltage change ΔVth of the sensing TFT is 0V, the change in the detection voltage with time is steeper than when the threshold voltage change ΔVth of the sensing TFT is 1V.
In addition, the threshold voltage of the sensing TFT can be estimated from the difference in the detected voltage at a predetermined time point after the increase in the detected voltage with respect to time change has almost reached saturation, for example, at 6 ms, 8 ms, and 10 ms.
After the increase in the detection voltage with respect to time changes becomes substantially saturated, the difference in the detection voltage with respect to time changes remains at a substantially constant value.

In conventional technology, the threshold voltage of the sensing TFT is fixed, but in practice, when compensating for degradation of the light-emitting element, the effect of the threshold voltage of the sensing TFT must be taken into account.

According to this embodiment, the threshold voltage of the sensing TFT is estimated, and the estimated threshold voltage is used to accurately sense the degradation of the OLED element.
Therefore, it is possible to appropriately compensate for deterioration of the light-emitting element.

The present invention is not limited to the above-described embodiment, but also includes various modifications in which components are added, deleted, or converted from the above-described configuration.

100 Light emitting display device 110 Timing controller 120 Data line driving circuit 130 Gate line driving circuit 140 Memory unit 200 Pixel 200R, 200W, 200G, 200B Sub-pixel 201R, 201W, 201G, 201B, 202R, 202W, 202G, 202B, 203R, 203W, 203G, 203B Transistor 204R, 204W, 204G, 204B Capacitor element 205R, 205W, 205G, 205B Light emitting element 300 Sensing unit 301 First switch 302 Second switch 303 ADC

Claims (9)

A method for driving a light emitting display device in which pixels having a plurality of sub-pixels, each of which is provided with a scanning TFT, a sensing TFT and a driving TFT, are arranged in a matrix, wherein gates of the scanning TFT and the sensing TFT are connected to a common scan line, one of a source and a drain of the scanning TFT is connected to a data signal line, the gate of the driving TFT is connected to the other of the source and drain of the scanning TFT, one of the source and drain of the driving TFT is connected to a high potential voltage line common to other sub-pixels, one of the source and drain of the sensing TFT is connected to a reference voltage supply and sensing detection line common to other sub-pixels , and the other of the source and drain of the sensing TFT is connected to the other of the source and drain of the driving TFT,
The light emitting display device is driven in a normal drive for displaying an image and a sensing drive for sensing deterioration,
The driving method includes:
a first step of turning on a driving TFT of one sub-pixel among a plurality of sub-pixels having a common reference voltage supply and sensing detection line, and maintaining driving TFTs of other sub-pixels in an off state;
a second step of setting the voltage of the scan line lower than the gate voltage of the driving TFT of the one sub-pixel that is turned on and higher than the voltage of the cathode of the light-emitting element;
a third step of sensing a threshold voltage of the sensing TFT by the reference voltage supply and sensing detection line ;
The method for driving a light-emitting display device , wherein the first step, the second step, and the third step are executed in this order during the sensing driving . calculating a compensation value of the light emitting device using a threshold voltage of the sensing TFT;
The method of claim 1 , further comprising: compensating for deterioration of the light emitting element using the compensation value of the light emitting element. 3. Compensating for deterioration of the pixel by compensating for deterioration of the other sub-pixels using the method for driving a light-emitting display device according to claim 2;
The method for driving a light-emitting display device further includes sequentially compensating for deterioration of the pixels arranged in a matrix by sequentially compensating for deterioration of the pixels. A panel including a normal drive and a sensing drive; and
comprising at least three sub-pixels in the panel, each of which emits a different color;
Each of the at least three sub-pixels includes a pixel circuit and a light emitting element;
the pixel circuit includes a scanning TFT, a sensing TFT, and a driving TFT, wherein gates of the scanning TFT and the sensing TFT are connected to a common scan line, one of a source and a drain of the scanning TFT is connected to a data signal line, the gate of the driving TFT is connected to the other of the source and the drain of the scanning TFT, one of the source and the drain of the driving TFT is connected to a high potential voltage line common to other sub-pixels, one of the source and the drain of the sensing TFT is connected to a reference voltage supply and sensing detection line common to other sub-pixels, and the other of the source and the drain of the sensing TFT is connected to the other of the source and the drain of the driving TFT,
In the sensing driving, a data voltage higher than that of the other subpixels is applied to one subpixel of the at least three subpixels, and the driving TFT of the one subpixel of the at least three subpixels is turned on while the driving TFT of the other subpixels is turned off;
In a sensing period of the sensing drive, a gate voltage of the sensing TFT of one of the at least three subpixels is made lower than a gate voltage of the driving TFT of the one subpixel, and a gate voltage of the sensing TFT is made higher than a cathode voltage of the light-emitting element, thereby sensing a threshold voltage of the sensing TFT . The light-emitting display device according to claim 4, wherein the sensing drive is performed during a power-off sequence period. The light-emitting display device according to claim 4, wherein the sensing drive includes an initialization period, a light-emitting period, and the sensing period. The light emitting display device according to claim 6 , wherein in the initialization period, a data voltage that turns on the driving TFT of the one sub-pixel is applied, and a data voltage of 0 V is applied to the other sub-pixels. The light-emitting display device according to claim 6 , wherein, during the light-emitting period, the light- emitting element of the one sub-pixel emits light, and the light - emitting element of the other sub-pixel does not emit light. The light emitting display device of claim 6 , wherein a voltage of 0 V is applied to the reference voltage supply and sensing detection lines during the light emitting period.

Images