KR102449681B1 - Organic light emitting display panel, organic light emitting display device and the method for driving the same - Google Patents

Abstract

The present embodiments relate to an organic light emitting display panel, an organic light emitting display device, and a driving method thereof, and are electrically connected to the same reference voltage line in order to shorten a time for sensing threshold voltages of driving transistors of all sub-pixels. When sensing and driving the subpixels located in the subpixel column, the gate node and the source node of the driving transistor are collectively initialized, and the voltage of the source node of the driving transistor is increased to reflect the threshold voltage. Following) operation is performed simultaneously, and the sampling process for actually sensing the voltage of the source node of the driving transistor reflecting the threshold voltage is sequentially performed, so that the subpixels located in the same subpixel column have the threshold for the driving transistor. The present invention relates to an organic light emitting display panel, an organic light emitting display device, and a method of driving the same, which can quickly sense a voltage.

Description

Organic light emitting display panel, organic light emitting display device, and driving method thereof

The present embodiments relate to an organic light emitting display panel, an organic light emitting display device, and a driving method thereof.

Recently, an organic light emitting display device, which has been spotlighted as a display device, has advantages of fast response speed, high luminous efficiency, luminance, and viewing angle by using an organic light emitting diode (OLED) that emits light by itself.

In such an organic light emitting display device, sub-pixels including an organic light emitting diode and a driving transistor for driving the same are arranged in a matrix form, and the brightness of the sub-pixels selected by a scan signal is controlled according to a gray level of data.

Meanwhile, as the driving time of each sub-pixel increases, a threshold voltage, which is a unique characteristic of a driving transistor in each sub-pixel, may change. A change in the threshold voltage of the driving transistor causes a change in luminance of the corresponding sub-pixel.

Also, since the driving time between each sub-pixel may be different from each other, a threshold voltage deviation between the driving transistors may occur.

The threshold voltage deviation between the driving transistors may cause a luminance deviation between sub-pixels to deteriorate the image quality of the organic light emitting display panel.

Accordingly, technologies for sensing and compensating the threshold voltage of the driving transistor are being developed.

However, conventional techniques have a problem in that it takes too long to sense the threshold voltages for the driving transistors of all sub-pixels disposed in the organic light emitting display panel.

As described above, if it takes a long time to sense the threshold voltages of the driving transistors of all sub-pixels disposed in the organic light emitting display panel, all sub-pixels are driven during sensing due to various unexpected reasons such as power cut off. Problems such as inability to sense the transistor may occur, and thus, a screen abnormality may occur.

An object of the present exemplary embodiments is to provide an organic light emitting display panel, an organic light emitting display device, and a driving method thereof, which can shorten a time for sensing the threshold voltages of driving transistors of all sub-pixels.

Another object of the present exemplary embodiments is to collectively initialize a gate node and a source node of a driving transistor, and to simultaneously initialize a gate node and a source node of a driving transistor when sensing and driving subpixels located in a subpixel column electrically connected to the same reference voltage line. A source-following operation in which the voltage rises so that the voltage reflects the threshold voltage is performed at once, and the sampling process for actually sensing the voltage of the source node of the driving transistor that reflects the threshold voltage is sequentially performed An object of the present invention is to provide an organic light emitting display panel, an organic light emitting display device, and a driving method thereof, which can quickly sense a threshold voltage for a driving transistor of sub-pixels located in the same sub-pixel column.

In one aspect, in the present embodiments, a plurality of data lines and a plurality of reference voltage lines are disposed in a first direction, a plurality of gate lines are disposed in a second direction, and are formed by a plurality of data lines and a plurality of gate lines. An organic light emitting display panel in which a plurality of defined sub-pixels are arranged in a matrix type, a data driver driving a plurality of data lines, a gate driver driving a plurality of gate lines, and a reference voltage line are electrically connected through a sampling switch It is possible to provide an organic light emitting display device including a connected sensing unit.

In such an organic light emitting diode display, each sub-pixel includes an organic light emitting diode, a driving transistor for driving the organic light emitting diode, a first transistor electrically connected between a first node of the driving transistor and a data line, and a second transistor of the driving transistor. It may include a second transistor electrically connected between the second node and the reference voltage line, and a storage capacitor electrically connected between the first node and the second node of the driving transistor.

In the organic light emitting diode display, during the sensing period, the data driver simultaneously supplies the sensing data voltage to the subpixels located in the same subpixel column and also supplies the reference voltage to the subpixels located in the same subpixel column.

In the organic light emitting diode display, during the sensing period, the sensing unit may be sequentially connected to subpixels positioned in the same subpixel column according to sequential switching operations of the sampling switch.

In another aspect, the present embodiments are defined by a plurality of data lines arranged in a first direction, a plurality of gate lines arranged in a second direction, a plurality of data lines and a plurality of gate lines, and arranged in a matrix type. It is possible to provide an organic light emitting display panel including a plurality of sub-pixels.

In such an organic light emitting display panel, each sub-pixel includes an organic light emitting diode, a driving transistor for driving the organic light emitting diode, a first transistor electrically connected between a first node of the driving transistor and a data line, and a first transistor of the driving transistor. It may include a second transistor electrically connected between the second node and the reference voltage line, and a storage capacitor electrically connected between the first node and the second node of the driving transistor.

In such an organic light emitting display panel, in subpixels located in the same subpixel column, during a sensing period, the first transistor and the second transistor are turned on together, and then the second transistor is turned off together, and then, thereafter, the second transistor is turned off. The transistor may be sequentially turned on and then turned off.

In another aspect, in the present embodiments, a plurality of sub-pixels defined by a plurality of data lines and a plurality of gate lines are arranged in a matrix type, and each sub-pixel has an organic light emitting diode, a driving for driving the organic light emitting diode A transistor, a first transistor electrically connected between the first node of the driving transistor and the data line, a second transistor electrically connected between the second node of the driving transistor and the reference voltage line, and between the first node and the second node of the driving transistor Provided is a method of driving an organic light emitting display device including an organic light emitting display panel having a storage capacitor electrically connected thereto, a data driver driving a plurality of data lines, and a gate driver driving the plurality of gate lines. .

This driving method includes a batch initialization step of turning on both the first transistor and the second transistor of subpixels positioned in the same subpixel column, and batch tracking of turning off the second transistor of subpixels positioned in the same subpixel column together. and a sequential sampling step of sequentially turning on and then turning off second transistors of subpixels located in the same subpixel column.

According to the present exemplary embodiments as described above, it is possible to provide an organic light emitting display panel, an organic light emitting display device, and a driving method thereof capable of reducing the time required for sensing the threshold voltages of the driving transistors of all sub-pixels.

Also, according to the present embodiments, when sensing and driving subpixels located in a subpixel column electrically connected to the same reference voltage line, the gate node and the source node of the driving transistor are collectively initialized, and the source node of the driving transistor is simultaneously initialized. A source-following operation in which the voltage rises to reflect the threshold voltage is performed at once, and the sampling process for actually sensing the voltage of the source node of the driving transistor reflecting the threshold voltage is sequentially performed It is possible to provide an organic light emitting display panel, an organic light emitting display device, and a driving method thereof, which can quickly sense a threshold voltage for a driving transistor of sub-pixels positioned in the same sub-pixel column.

1 is a system configuration diagram of an organic light emitting diode display according to example embodiments.
2 is an exemplary diagram of a sub-pixel structure of an organic light emitting display panel according to the present exemplary embodiment.
3 is an exemplary diagram of a compensation circuit of an organic light emitting diode display according to example embodiments.
4 is a diagram for explaining a threshold voltage sensing method for a driving transistor of an organic light emitting diode display according to the present exemplary embodiment.
5 and 6 are diagrams for explaining a procedure for sensing all sub-pixels of the organic light emitting display panel according to the present exemplary embodiment.
7 is a flowchart of a bundle sensing method of an organic light emitting diode display according to the present exemplary embodiment.
8 is a diagram illustrating operation timings of two transistors T1 and T2 in each subpixel positioned in the same subpixel column and operation timings of main switches during bundle sensing of the organic light emitting diode display according to the present exemplary embodiments; , is a diagram showing the voltage change of the second node of the driving transistor in each subpixel located in the same subpixel column.
FIG. 9 is a diagram illustrating a batch initialization step during bundle sensing of the organic light emitting diode display according to the present exemplary embodiments.
10 is a diagram illustrating a batch tracking step during bundle sensing of the organic light emitting diode display according to the present embodiments.
11 to 14 are diagrams illustrating sequential sampling steps during bundle sensing of the organic light emitting diode display according to the present embodiments.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It should be understood that each component may be “interposed” or “connected,” “coupled,” or “connected” through another component.

1 is a system configuration diagram of an organic light emitting diode display 100 according to the present exemplary embodiment.

Referring to FIG. 1 , in the organic light emitting diode display 100 according to the present exemplary embodiments, a plurality of data lines DL and a plurality of gate lines GL are disposed, and a plurality of data lines DL and a plurality of data lines DL are disposed. The organic light emitting display panel 110 in which a plurality of subpixels SP defined by the gate line GL are arranged in a matrix type, the data driver 120 driving the plurality of data lines DL, and the plurality of It includes a gate driver 130 for driving the gate line GL, a data driver 120 , and a controller 140 for controlling the gate driver 130 .

In the organic light emitting display panel 110 , a plurality of data lines DL are disposed in a first direction (eg, a column direction) and a plurality of gate lines GL are disposed in a second direction (eg, a row direction).

In the organic light emitting display panel 110 , not only a plurality of data lines DL, but also a plurality of reference voltage lines (RVL) and a plurality of driving voltage lines (DVD) are disposed in a first direction. can be

The controller 140 supplies various control signals to the data driver 120 and the gate driver 130 to control the data driver 120 and the gate driver 130 .

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

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

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

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

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

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

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

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

Although the data driver 120 is located only on one side (eg, upper or lower side) of the organic light emitting display panel 110 in FIG. 1 , both sides (eg, the organic light emitting display panel 110 ) according to a driving method and a panel design method. : It may be located both above and below).

Although the gate driver 130 is located only on one side (eg, left or right) of the organic light emitting display panel 110 in FIG. 1 , the gate driver 130 is located on both sides of the organic light emitting display panel 110 according to a driving method, a panel design method, etc. For example, it can be located on both the left and right side).

The above-described controller 140, along with the input image data, a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input data enable (DE: Data Enable) signal, various types including a clock signal (CLK), etc. Timing signals are received from the outside (eg host system).

The controller 140 receives timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input DE signal, and a clock signal to control the data driver 120 and the gate driver 130, Various control signals are generated and output to the data driver 120 and the gate driver 130 .

For example, in order to control the gate driver 130 , the controller 140 may include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE). Various gate control signals (GCS: Gate Control Signal) including Gate Output Enable) are output.

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver integrated circuits constituting the gate driver 130 . The gate shift clock GSC is a clock signal commonly input to one or more gate driver integrated circuits and controls shift timing of a scan signal (gate pulse). The gate output enable signal GOE specifies timing information of one or more gate driver integrated circuits.

In addition, the controller 140 controls the data driver 120 , a source start pulse (SSP), a source sampling clock (SSC), and a source output enable signal (SOE: Source Output). Enable) and output various data control signals (DCS: Data Control Signal).

Here, the source start pulse SSP controls the data sampling start timing of one or more source driver integrated circuits constituting the data driver 120 . The source sampling clock SSC is a clock signal that controls sampling timing of data in each of the source driver integrated circuits. The source output enable signal SOE controls the output timing of the data driver 120 .

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

Each source driver integrated circuit SDIC is connected to a bonding pad of the organic light emitting display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method. It may be connected to or directly disposed on the organic light emitting display panel 110 , or may be integrated and disposed on the organic light emitting display panel 110 in some cases. In addition, each source driver integrated circuit SDIC may be implemented in a Chip On Film (COF) method mounted on a film connected to the organic light emitting display panel 110 .

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

Each source driver integrated circuit SDIC may further include an analog-to-digital converter (ADC) in some cases.

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

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

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

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

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

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

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

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

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

Each subpixel SP disposed in the organic light emitting display panel 110 may include circuit elements such as transistors.

For example, each sub-pixel SP includes circuit elements such as an organic light emitting diode (OLED) and a driving transistor for driving the organic light emitting diode (OLED).

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

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

Referring to FIG. 2 , in the organic light emitting diode display 100 according to the present exemplary embodiments, each sub-pixel includes an organic light emitting diode (OLED) and a driving transistor for driving the organic light emitting diode (OLED). (DRT: Driving Transistor), a first transistor T1 for transferring a data voltage to a first node N1 corresponding to a gate node of the driving transistor DRT, and a second node ( N2) and a second transistor T2 electrically connected between a reference voltage line (RVL) supplying a reference voltage (Vref), and a data voltage corresponding to the image signal voltage or corresponding It may be configured by including a storage capacitor (Cstg: Storage Capacitor) that maintains the voltage for one frame time.

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

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

In the driving transistor DRT, the first node N1 may be electrically connected to a source node or a drain node of the first transistor T1 and may be a gate node. The second node N2 may be electrically connected to the first electrode of the organic light emitting diode OLED, and may be a source node or a drain node. The third node N3 may be electrically connected to a driving voltage line (DVL) that supplies the driving voltage EVDD, and may be a drain node or a source node.

The first transistor T1 may be electrically connected between the data line DL and the first node N1 of the driving transistor DRT, and may be controlled by receiving the scan signal SCAN as a gate node through the gate line. have.

The first transistor T1 is turned on by the scan signal SCAN to transfer the data voltage Vdata supplied from the data line DL to the first node N1 of the driving transistor DRT. .

The second transistor T2 may be controlled by receiving a sensing signal SENSE, which is a type of scan signal, as a gate node.

The second transistor T2 is turned on by the sensing signal SENSE to apply the reference voltage Vref supplied through the reference voltage line RVL to the second node N2 of the driving transistor DRT. .

Also, the second transistor T2 may be used as one of the voltage sensing paths for the second node N2 of the driving transistor DRT.

The driving transistor DRT, the first transistor T1 , and the second transistor T2 may be implemented as an n-type or a p-type as illustrated in FIG. 2 .

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

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

Meanwhile, the scan signal SCAN and the sensing signal SENSE may be separate gate signals. In this case, the scan signal SCAN and the sensing signal SENSE may be respectively applied to the gate node of the first transistor T1 and the gate node of the second transistor T2 through different gate lines.

In some cases, the scan signal SCAN and the sensing signal SENSE may be the same gate signal. In this case, the scan signal SCAN and the sensing signal SENSE may be commonly applied to the gate node of the first transistor T1 and the gate node of the second transistor T2 through the same gate line.

Meanwhile, in the case of the organic light emitting diode display 100 according to the present exemplary embodiments, as the driving time of each sub-pixel SP increases, the threshold voltage, which is a unique characteristic of the driving transistor DRT in each sub-pixel SP, decreases. can change

A change in the threshold voltage of the driving transistor DRT causes a change in the luminance of the corresponding sub-pixel SP.

In addition, since the driving time between the respective subpixels SP may be different from each other, a threshold voltage deviation may occur between the driving transistors DRT, thereby causing a luminance deviation between the subpixels.

Accordingly, the organic light emitting diode display 100 according to the present exemplary embodiments includes a “sensing function” for sensing a threshold voltage (or a threshold voltage change) of each driving transistor DRT or a threshold voltage deviation between the driving transistors DRT; , it is possible to provide a “compensation function” for compensating for a threshold voltage deviation between the driving transistors DRT or a luminance deviation between the sub-pixels SP using the sensing result.

The organic light emitting diode display 100 according to the present exemplary embodiments may include the compensation circuit illustrated in FIG. 3 to provide a sensing function and a compensation function.

3 is an exemplary diagram of a compensation circuit of the organic light emitting diode display 100 according to the present exemplary embodiment.

Referring to FIG. 3 , the organic light emitting diode display 100 according to the present exemplary embodiments senses a change in a threshold voltage of a driving transistor DRT or a threshold voltage deviation between the driving transistors DRT, and a sensing unit outputs sensed data. 310), a memory 320 for storing sensed data, and a compensating unit ( 330) and the like.

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

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

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

The sensing data output from the sensing unit 310 may be, for example, in a low voltage differential signaling (LVDS) data format.

The organic light emitting diode display 100 according to the present exemplary embodiments may further include an initialization switch SPRE and a sampling switch SAM to control a threshold voltage sensing state.

The initialization switch SPRE switches the connection between the reference voltage supply node Nref and the reference voltage line RVL.

When the initialization switch SPRE is turned on, when the reference voltage supply node Nref and the reference voltage line RVL are connected, the reference voltage Vref is supplied to the reference voltage line RVL.

When the initialization switch SPRE is turned on and the second transistor T2 is also turned on, the reference voltage Vref is supplied to the reference voltage line RVL to turn on the turned-on second transistor T2. through the second node N2 of the driving transistor DRT.

The sampling switch SAM switches the connection between the reference voltage line RVL and the sensing unit 310 .

On the other hand, when the voltage of the second node N2 of the driving transistor DRT reaches a voltage state that reflects the threshold voltage of the driving transistor DRT, it may be equal to the second node N2 of the driving transistor DRT. The voltage of the reference voltage line RVL may also be in a voltage state reflecting the threshold voltage of the driving transistor DRT.

In this case, a voltage reflecting the threshold voltage of the driving transistor DRT may be charged in the line capacitor Cp formed on the reference voltage line RVL.

When the voltage of the second node N2 of the driving transistor DRT reaches a voltage state reflecting the threshold voltage of the driving transistor DRT, the sampling switch SAM is turned on, and the sensing unit 310 and the reference voltage are turned on. A line RVL may be connected.

Accordingly, the sensing unit 310 senses the voltage of the reference voltage line RVL, which is the threshold voltage of the driving transistor DRT or a voltage state reflecting the change thereof.

That is, when the sensing unit 310 is connected to the reference voltage line RVL, it is the voltage of the second node N2 of the driving transistor DRT, which is the voltage of the reference voltage line RVL or the voltage on the reference voltage line RVL. The voltage charged in the line capacitor Cp is sensed.

The voltage sensed by the sensing unit 310 may be a voltage value Vdata-Vth or Vdata-ΔVth including a threshold voltage Vth or a threshold voltage deviation ΔVth of the driving transistor DRT.

Hereinafter, the threshold voltage sensing driving of the driving transistor DRT will be briefly described.

4 is a diagram for explaining a threshold voltage sensing method for the driving transistor DRT of the organic light emitting diode display 100 according to the present exemplary embodiment.

The threshold voltage sensing driving of the driving transistor DRT includes an initialization step of applying a positive voltage to each of the first node N1 and the second node N2 of the driving transistor DRT, and the second of the driving transistor DRT. A tracking step in which the voltage of the node N2 tracks a voltage reflecting the threshold voltage Vth, and a sampling step of sensing a voltage reflecting the threshold voltage Vth are performed.

In the initialization step, each of the second node N2 and the first node N1 of the driving transistor DRT is initialized to the reference voltage Vref and the threshold voltage sensing driving data voltage Vdata.

Thereafter, the tracking phase starts as the initialization switch SPRE is turned off and the second node N2 of the driving transistor DRT is floated. At this time, the second transistor T2 may be turned off.

In the tracking step, the voltage of the second node N2 of the driving transistor DRT rises.

The voltage of the second node N2 of the driving transistor DRT rises and then gradually decreases and becomes saturated.

The saturated voltage of the second node N2 of the driving transistor DRT may correspond to the difference between the data voltage Vdata and the threshold voltage Vth or the difference between the data voltage Vdata and the threshold voltage deviation ΔVth. .

As described above, the sampling step may be performed after the point in time when the voltage of the second node N2 of the driving transistor DRT is saturated.

When the sampling step is performed, when the voltage of the second node N2 of the driving transistor DRT is saturated, the sensing unit 310 senses the saturated voltage of the second node N2 of the driving transistor DRT.

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

The sensing unit 310 converts the sensed voltage Vsen into a digital value for threshold voltage sensing, and generates and outputs sensing data including the converted digital value (sensing value).

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

The compensator 330 may determine the threshold voltage of the driving transistor DRT in the corresponding sub-pixel based on sensing data stored in the memory 320 or provided from the sensing unit 310 , and may perform a threshold voltage compensation process.

Here, the change in the threshold voltage of the driving transistor DRT may mean that the current sensed data is changed based on the previous sensed data or that the current sensed data is changed based on the reference sensed data.

Here, by comparing the threshold voltage or the threshold voltage change between the driving transistors DRT, the threshold voltage deviation between the driving transistors DRT can be recognized.

In the threshold voltage compensation process, a compensation value for compensating for a threshold voltage or a threshold voltage deviation (threshold voltage change) is calculated, and the calculated compensation value is stored in the memory 320, or the image data (Data ) may be included.

The compensator 330 may change the image data Data through the threshold voltage compensation process and supply the changed data to the corresponding source driver integrated circuit SDIC in the data driver 120 .

Accordingly, the corresponding source driver integrated circuit SDIC converts the data changed by the compensator 330 into a data voltage through a digital-to-analog converter (DAC) 340 and supplies it to the corresponding sub-pixel. Voltage compensation is actually done.

As the threshold voltage characteristic value compensation is performed, image quality may be improved by reducing or preventing a luminance deviation between sub-pixels.

Meanwhile, in the organic light emitting display device 100 according to the present exemplary embodiments, after a power-off signal is generated according to a user input, the threshold voltage of the driving transistor DRT in each subpixel disposed in the organic light emitting display panel 110 . can be sensed.

5 and 6 are diagrams for explaining a procedure for sensing all sub-pixels disposed on the organic light emitting display panel 110 according to the present exemplary embodiment.

One reference voltage line RVL may be disposed in each subpixel column, or may be disposed in each of two or more subpixel columns.

As shown in FIG. 5 , when one pixel is composed of four sub-pixels, one reference voltage line RVL may be arranged in every four sub-pixel columns.

Referring to FIG. 5 , when there are 4m sub-pixel columns C1, C2, ..., C4m in the organic light emitting display panel 110, m (=4m/4) reference voltage lines RVL1, RVL2, ..., RVLm) may be deployed.

For example, when one pixel is composed of a red sub-pixel (R), a white sub-pixel (W), a blue sub-pixel (B), and a green sub-pixel (G), the reference voltage line RVL is a red sub-pixel column ( C1, C5, …, C4m-3), white subpixel column (C2, C6, …,C4m-2), blue subpixel column (C3, C7, …, C4m-1), green subpixel column (C4, C8 and C4m), one pixel column may be disposed.

As shown in FIG. 5 , when the reference voltage line RVL is shared by the four sub-pixels R, W, B, and G, sensing of the four sub-pixels R, W, B, and G is performed. cannot be done at the same time.

Referring to FIG. 6 , when a sensing driving period in which all threshold voltages of all sub-pixels disposed on the organic light emitting display panel 110 are sensed starts, sensing driving is performed in units of sub-pixel rows.

That is, when the sensing driving of the subpixels positioned in each subpixel row is completed, the sensing driving of the subpixels positioned in the next subpixel row is performed.

5 and 6, in the first sub-pixel row R1, m red sub-pixels R are simultaneously sensed using m reference voltage lines RVL1, RVL2, ..., RVLm, and then , m simultaneously sensing m white sub-pixels W using m reference voltage lines RVL1, RVL2, …, RVLm, and then using m reference voltage lines RVL1, RVL2, …, RVLm. The m blue subpixels B are simultaneously sensed, and then, the m green subpixels G are simultaneously sensed using the m reference voltage lines RVL1, RVL2, ..., RVLm.

In the second subpixel row R2, m red subpixels R are simultaneously sensed using m reference voltage lines RVL1, RVL2, ..., RVLm, and thereafter, m reference voltage lines RVL1, RVL2, …, RVLm) are used to simultaneously sense m white sub-pixels W, and then, m blue sub-pixels B are used to sense m reference voltage lines RVL1, RVL2, …, RVLm. Simultaneous sensing is performed, and then, m green subpixels G are simultaneously sensed using m reference voltage lines RVL1, RVL2, ..., RVLm.

In this way, for m red subpixels (R), m white subpixels (W), m blue subpixels (B), m green subpixels (G) located in the last subpixel row Rn When sensing is completed, all threshold voltages of the driving transistors DRT in all sub-pixels located in the organic light emitting display panel 110 are sensed.

As described above, in order to sense all threshold voltages of the driving transistors DRT in all subpixels disposed in the organic light emitting display panel 110 , the voltage of the second node N2 of the driving transistor DRT is Because it takes a long time to saturate and the threshold voltage sensing driving is performed in units of sub-pixel rows, a fairly long time is required.

As described above, if it takes a long time to sense the threshold voltages of the driving transistors of all sub-pixels disposed in the organic light emitting display panel, all sub-pixels are driven during sensing due to various unexpected reasons such as power cut off. Problems such as inability to sense the transistor may occur, and thus, a screen abnormality may occur.

Accordingly, the present embodiments provide a bundle sensing method capable of shortening the sensing time by simultaneously performing sensing driving for subpixels located in the same subpixel column.

7 is a flowchart of a bundle sensing method of the organic light emitting display device 100 according to the present exemplary embodiments, and FIG. 8 is a bundle sensing method of the organic light emitting display device 100 according to the present exemplary embodiments. ), the operation timing of the two transistors T1 and T2 of each of the subpixels SP1, SP2, ... , SPn located in the same subpixel column and the operation timing of the main switches SPRE and SAM, It is a view showing the voltage change of the second node N2 of the driving transistor DRT of each of the sub-pixels SP1, SP2, ..., SPn located in the sub-pixel column. It is a view showing a batch initialization step when the light emitting display device 100 senses the bundle. 14 to 14 are diagrams illustrating sequential sampling steps during bundle sensing of the organic light emitting diode display 100 according to the present exemplary embodiments.

The organic light emitting diode display 100 according to the present exemplary embodiments provides a bundle sensing method for simultaneously performing sensing driving on the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column.

Meanwhile, the threshold voltage sensing includes an initialization process of initializing the first node N1 and the second node N2 of the driving transistor DRT to the data voltage Vdata and the reference voltage Vref, and the driving transistor DRT. A tracking process of increasing the voltage of the second node N2 to a voltage reflecting the threshold voltage and a sampling process of actually sensing the voltage reflecting the threshold voltage through the reference voltage line RVL are performed.

In this regard, the bundle sensing method according to the present embodiments includes an initialization process and a tracking process for the subpixels SP1, SP2, ..., SPn located in the same subpixel column, as shown in FIG. 8 . Together, the sampling process proceeds sequentially.

Referring to FIG. 7 , in the bundle sensing method of the organic light emitting diode display 100 according to the present exemplary embodiments, subpixels SP1, SP2, ... , SPn, n located in the same subpixel column are A batch initialization step S710 of turning on both the first transistor T1 and the second transistor T2 (a natural number equal to or greater than 2), and the subpixels SP1 and SP2 located in the same subpixel column. Batch tracking step S720 of turning off the second transistor T2 of ... , SPn together, and subpixels SP1, SP2, ... , SPn located in the same subpixel column ) may include a sequential sampling step ( S730 ) of sequentially turning on and then turning off the second transistor T2 .

The on-off of the first transistor T1 is controlled by the scan signal SCAN, and the on-off of the second transistor T2 is controlled by the sensing signal SENSE.

According to the above-described driving method, initialization and tracking of the sub-pixels SP1, SP2, ... , SPn located in the same sub-pixel column are collectively performed and sampling is sequentially performed, so that the sub-pixels located in the same sub-pixel column are sub-pixels. The total time taken to sense all the pixels SP1, SP2, ..., SPn can be greatly reduced.

In the batch initialization step S710 in which the initialization process for the subpixels SP1, SP2, ... , SPn located in the same subpixel column is performed together, the data of the organic light emitting diode display 100 according to the present embodiments The driver 120 supplies the sensing data voltage Vdata to the sub-pixels SP1, SP2, ..., SPn located in the same sub-pixel column, and also supplies the sensing data voltage Vdata to the sub-pixels SP1 and SP2 located in the same sub-pixel column. , ... , SPn) is supplied with the reference voltage (Vref).

That is, in the batch initialization step S710 , the data driver 120 uses the first node N1 of the driving transistor DRT of the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column. The sensing data voltage Vdata is supplied together, and the reference voltage Vref is applied to the second node N2 of the driving transistor DRT of the subpixels SP1, SP2, ..., SPn located in the same subpixel column. can be supplied together.

According to the operation of the data driver 120 , the driving transistor DRT included in the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column electrically connected to the same reference voltage line RVL is reduced. The first node N1 and the second node N2 may be collectively initialized.

8 and 10 , in the batch tracking step S720 in which the tracking process for the subpixels SP1, SP2, ..., SPn located in the same subpixel column is performed together, the subpixels located in the same subpixel column The second node N2 of the driving transistor DRT of the pixels SP1, SP2, ..., SPn is collectively floated to increase the voltage.

That is, if it is assumed that the second node N2 of the driving transistor DRT is a source node, in the batch tracking step S720 , the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column are The driving transistor DRT simultaneously performs a source following operation.

In this way, the second node N2 of the driving transistor DRT of the subpixels SP1, SP2, ..., SPn positioned in the same subpixel column is collectively floated to simultaneously increase the voltage, that is, The tracking process, which takes the most time when sensing the threshold voltage, is simultaneously performed on the sub-pixels SP1, SP2, ..., SPn located in the same sub-pixel column, so that the sub-pixels SP1, SP2, . .. , SPn), the time taken to sense all the threshold voltages of the driving transistor (DRT) can be greatly reduced.

In the sequential sampling step S730 of sequentially performing the sampling process for the subpixels SP1, SP2, ... , SPn located in the same subpixel column, the sampling switch SAM sequentially performs a switch operation, The sensing unit 310 is sequentially connected to the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column according to the sequential switching operation of the sampling switch SAM.

As described above, the initialization process and tracking process for the sub-pixels SP1, SP2, ... , SPn located in the same sub-pixel column that can be electrically connected to the same reference voltage line RVL are performed simultaneously and By sequentially performing the sampling process (sensing process), the sensing driving of the sub-pixels SP1, SP2, ... , SPn located in the same sub-pixel column can be performed together, so that the organic light emitting display panel 110 . It is possible to greatly reduce the total time required to sense all the subpixels disposed in .

8 and 11 to 14 , in the sequential sampling step S730 , the second transistor T2 of the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column is sequentially applied. Turn it on and then turn it off.

When the second transistor T2 of one of the sub-pixels SP among the sub-pixels SP1, SP2, ..., SPn located in the same sub-pixel column is turned on, the sensing unit 310 is turned on. senses the voltage of the reference voltage line RVL.

At this time, the voltage Vsen sensed by the sensing unit 310 is a voltage Vdata-Vth or Vdata reflecting the threshold voltage of the driving transistor DRT in the subpixel including the turned-on second transistor T1 . -ΔVth).

As described above, the sampling process for actually sensing the threshold voltage of the driving transistor DRT of the sub-pixels SP1, SP2, ..., SPn connected to the same reference voltage line RVL is sequentially performed, Threshold voltages of the sub-pixels SP1, SP2, ..., SPn located in the same sub-pixel column can be distinguished from each other and accurately sensed.

In the sequential sampling step S730 , the sensing unit 310 detects the threshold voltages of the driving transistors DRT of the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column through sequential sampling. The reflected voltages (Vsen_1, Vsen_2, …, Vsen_n) are sensed several times through the reference voltage line (RVL), and n sensing voltages (Vsen_1, Vsen_2, …, Vsen_n) obtained in this way are converted into digital values. Transmits sensing data including values.

On the other hand, in the batch initialization step S710 and the batch tracking step S720 for bundle sensing, the switching operation of the initialization switch SPRE connected between the reference voltage Vref supply node and the reference voltage line RVL is as follows. same.

8 and 9 , the initialization switch SPRE causes the data driver 120 to supply the reference voltage Vref to the subpixels SP1, SP2, ..., SPn located in the same subpixel column. When, that is, the batch initialization step (S710) is turned on (Turn-On).

Referring to FIG. 8 , in the initialization switch SPRE, after the data driver 120 supplies the reference voltage Vref to the subpixels SP1, SP2, ..., SPn located in the same subpixel column, That is, after the batch initialization step ( S710 ), it is turned off.

According to the above-described switching operation of the initialization switch SPRE, the batch initialization step S710 may be controlled to start, and the batch initialization step S710 may be terminated and the batch tracking step S720 may be controlled to start.

Below, in relation to the batch initialization step S710 , the batch tracking step S720 , and the sequential sampling step S730 for bundle sensing, subpixels SP1 located in the same subpixel column connected to the same reference voltage line RVL How the second transistor T2 of , SP2, ... , SPn operates on-off will be described.

Referring to FIG. 8 , the second transistors T2 of the subpixels SP1 , SP2 , ... , SPn positioned in the same subpixel column are all turned on for batch initialization.

Thereafter, the second transistor T2 of the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column turns off the initialization switch SPRE for batch tracking (source following operation) All are turned off (Turn-Off) at the time.

After the second transistor T2 of the subpixels SP1, SP2, ..., SPn located in the same subpixel column is turned off at the turn-off point of the initialization switch SPRE, the After a certain period of time has elapsed, it is sequentially turned on and then turned off.

In other words, in the batch initialization step S710 and the batch tracking step S720 , the second transistors T2 of the subpixels SP1 , SP2 , ... , SPn located in the same subpixel column are turned on together. turns off together.

In the sequential sampling step S730, among the subpixels SP1, SP2, ..., SPn located in the same subpixel column, SP1, SP2, ... , SPn is turned off when the second transistor T2 is turned on.

8 and 11 to 14 , the operation timing of the second transistor T2 of each of the subpixels SP1 , SP2 , ... , SPn positioned in the same subpixel column is determined by the sampling switch SAM It corresponds to the switching operation timing of

As described above, according to the on-off operation of the second transistor T2 of the sub-pixels SP1, SP2, ..., SPn connected to the same reference voltage line RVL, batch initialization and batch tracking By enabling (source following) and sequential sampling, the driving transistors DRT of the sub-pixels SP1, SP2, ... , SPn connected to the same reference voltage line RVL through a single sensing operation ) of the threshold voltage can be sensed.

Referring to FIG. 8 , the gate signal SCAN applied to the gate node of the first transistor T1 and the gate signal SENSE applied to the gate node of the second transistor T2 are connected to the gate shift clock GSC. can be controlled by

The frequency F1 of the gate shift clock GSC in the batch initialization step S710 and the batch tracking step S720 and the frequency F2 of the gate shift clock signal GSC in the sequential sampling step S730 are mutually can be different.

For example, the frequency F1 of the gate shift clock GSC in the batch initialization step S710 and the batch tracking step S720 is the frequency F2 of the gate shift clock signal GSC in the sequential sampling step S730 . higher than

As described above, by controlling the gate signals SCAN and SENSE of the first transistor T1 and the second transistor T2, bundle sensing through batch initialization, batch tracking (source following), and sequential sampling can be provided efficiently.

The organic light emitting display panel 110 to which the bundle sensing driving according to the present embodiments is applied includes a plurality of data lines DL disposed in a first direction, a plurality of gate lines GL disposed in a second direction, and , a plurality of subpixels SP defined by a plurality of data lines DL and a plurality of gate lines GL and arranged in a matrix type.

Each subpixel SP includes an organic light emitting diode OLED, a driving transistor DRT for driving the organic light emitting diode OLED, a first node N1 of the driving transistor DRT, and a data line DL ), a first transistor T1 electrically connected between ) and a storage capacitor (Cstg) electrically connected between the first node (N1) and the second node (N2).

During the sensing period, in the subpixels SP1, SP2, ... , SPn located in the same subpixel column, the first transistor T1 and the second transistor T2 are turned on together ( S710), then, the second transistor T2 is turned off together (S720), and thereafter, the second transistor T2 is sequentially turned on (Turn-On) and then turned off (S720). (Turn-Off) becomes (S730).

As described above, the threshold voltages of the driving transistors DRT of the sub-pixels SP1, SP2, ..., SPn located in the same sub-pixel column are measured in the same sensing driving process (initialization and tracking process performed at the same time period). It is possible to provide the organic light emitting display panel 110 that can be obtained together through one-time sensing driving).

According to the present embodiments as described above, the organic light emitting display panel 110, the organic light emitting display device ( 100) and a driving method thereof.

Also, according to the present exemplary embodiments, when sensing and driving subpixels located in a subpixel column electrically connected to the same reference voltage line RVL, the gate node N1 and the source node N2 of the driving transistor DRT to collectively initialize , and a source following operation in which the voltage rises so that the voltage of the source node N2 of the driving transistor DRT reflects the threshold voltage Vth is performed at once, and the threshold The sampling process for actually sensing the voltage of the source node N2 of the driving transistor DRT reflecting the voltage Vth is sequentially performed, so that the subpixels located in the same subpixel column have a threshold for the driving transistor DRT. It is possible to provide the organic light emitting display panel 110, the organic light emitting display device 100, and a driving method thereof that enable the voltage Vth to be quickly sensed.

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

100: organic light emitting display device
110: organic light emitting display panel
120: data driver
130: gate driver
140: controller

Claims (10)

A plurality of data lines and a plurality of reference voltage lines are disposed in a first direction, a plurality of gate lines are disposed in a second direction, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines are matrix type. an organic light emitting display panel disposed as
a data driver driving the plurality of data lines;
a gate driver driving the plurality of gate lines; and
A sensing unit electrically connected to the reference voltage line through a sampling switch,
Each sub-pixel is
an organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a first transistor electrically connected between a first node of the driving transistor and a data line; a second transistor electrically connected between a second node of the driving transistor and a reference voltage line; and a storage capacitor electrically connected between the first node and the second node of the driving transistor,
During the sensing period,
the data driver supplies a sensing data voltage together to subpixels located in the same subpixel column, and supplies a reference voltage to the subpixels located in the same subpixel column together;
The sensing unit is sequentially connected to the subpixels positioned in the same subpixel column according to the sequential switching operation of the sampling switch. According to claim 1,
Further comprising an initialization switch connected between the reference voltage supply node and the reference voltage line,
The initialization switch is
is turned on when the data driver supplies the reference voltage together to the subpixels located in the same subpixel column;
After the data driver supplies the reference voltage to the subpixels located in the same subpixel column, the organic light emitting diode display is turned off. 3. The method of claim 2,
the second transistor of subpixels located in the same subpixel column,
All turned off at the turn-off time of the initialization switch,
An organic light emitting diode display that is sequentially turned on and then turned off after a predetermined time has elapsed from the turn-off point of the initialization switch. According to claim 1,
The operation timing of the second transistor of each of the sub-pixels located in the same sub-pixel column is,
An organic light emitting diode display corresponding to a timing of a switching operation of the sampling switch. a plurality of data lines arranged in a first direction;
a plurality of gate lines arranged in a second direction; and
a plurality of subpixels defined by a plurality of data lines and a plurality of gate lines and arranged in a matrix type;
Each sub-pixel is
organic light emitting diode;
a driving transistor for driving the organic light emitting diode;
a first transistor electrically connected between a first node of the driving transistor and a data line;
a second transistor electrically connected between a second node of the driving transistor and a reference voltage line; and
a storage capacitor electrically connected between the first node and the second node of the driving transistor;
The sensing period includes a batch initialization period, a batch tracking period, and a sequential sampling period,
During the batch initialization period, the first transistor of each of the subpixels located in the same subpixel column is turned on together, and the second transistor of each of the subpixels located in the same subpixel column is turned on together;
After the batch initialization period, during the batch tracking period, the second transistors of each of the subpixels located in the same subpixel column are turned off together;
After the batch tracking period, during the sequential sampling period, the second transistor of each of the subpixels positioned in the same subpixel column is sequentially turned on and then turned off. A plurality of subpixels defined by a plurality of data lines and a plurality of gate lines are arranged in a matrix type, and each subpixel includes an organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a first node of the driving transistor and a first transistor electrically connected between the data line, a second transistor electrically connected between the second node of the driving transistor and a reference voltage line, and a storage capacitor electrically connected between the first node and the second node of the driving transistor. A driving method of an organic light emitting display device comprising: an organic light emitting display panel disposed thereon; a data driver driving the plurality of data lines; and a gate driver driving the plurality of gate lines;
a batch initialization step of turning on the first transistor and the second transistor of subpixels located in the same subpixel column together;
a batch tracking step of turning off the second transistors of the subpixels located in the same subpixel column together; and
and a sequential sampling step of sequentially turning on and then turning off the second transistor of the subpixels located in the same subpixel column. 7. The method of claim 6,
In the batch initialization step, the data driver,
a data voltage for sensing is supplied to the first node of the driving transistor of the sub-pixels located in the same sub-pixel column;
A method of driving an organic light emitting display device in which a reference voltage is also supplied to a second node of the driving transistor of the subpixels located in the same subpixel column. 7. The method of claim 6,
In the batch tracking step,
The second node of the driving transistor of the sub-pixels located in the same sub-pixel column is collectively floated to increase the voltage. 7. The method of claim 6,
In the sequential sampling step,
The second transistors of the subpixels located in the same subpixel column are sequentially turned on and then turned off,
When the second transistor of one of the sub-pixels among the sub-pixels positioned in the same sub-pixel column is turned on, the driving method of the organic light emitting display device senses the voltage of the reference voltage line. 7. The method of claim 6,
The gate signal applied to the gate node of the first transistor and the gate signal applied to the gate node of the second transistor are controlled by a gate shift clock,
The frequency of the gate shift clock in the batch initialization step and the batch tracking step and the frequency of the gate shift clock signal in the sequential sampling step are different from each other.

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