KR102460539B1 - Organic light emitting display panel, organic light emitting display device, source driver ic, operating method of the source driver ic, and driving method of the organic light emitting display device - Google Patents

Abstract

In the present exemplary embodiments, each sub-pixel is controlled by an organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a first scan signal, and is electrically connected between a first node of the driving transistor and a data line. a transistor, a second transistor controlled by the second scan signal and electrically connected between the second node of the driving transistor and a ground node, and a first capacitor electrically connected between the first node and the second node of the driving transistor An organic light emitting display device comprising: an organic light emitting display panel disposed thereon; and a switch circuit electrically connecting one of a first switch node to which a data voltage is input and a second switching node connected to an analog-to-digital converter to a data line; A driving method, a source driver integrated circuit including a switch circuit, and an operating method thereof. According to the present exemplary embodiments, characteristics of the organic light emitting diode and the driving transistor may be sensed and compensated in real time while an image is displayed on the screen, and a panel design structure and a panel manufacturing process may be simplified.

Description

Organic light emitting display panel, organic light emitting display device, source driver integrated circuit, source driver integrated circuit operation method, and organic light emitting display device driving method SOURCE DRIVER IC, AND DRIVING METHOD OF THE ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present embodiments relate to an organic light emitting display panel, an organic light emitting display device, a source driver integrated circuit, a method of operating a source driver integrated circuit, and a method of driving an organic light emitting display device.

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 organic light emitting diodes 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.

In such an organic light emitting display panel, each sub-pixel includes an organic light emitting diode and a driving transistor for driving the organic light emitting diode.

Meanwhile, as the driving time of the organic light emitting display panel increases, deterioration of the organic light emitting diode and the driving transistor disposed in each sub-pixel of the organic light emitting display panel may proceed.

According to the driving of each subpixel of the organic light emitting display panel, unique characteristic values of the organic light emitting diode and the driving transistor disposed in each subpixel may be changed.

The driving time may be different for each subpixel, and accordingly, the degree of deterioration of the organic light emitting diode and the driving transistor disposed in each subpixel may also be different. , driving transistors) may have a characteristic value deviation.

The variation in the characteristic values between circuit elements of the sub-pixels may cause a luminance variation between the sub-pixels, which may be a major factor in significantly lowering image quality.

Accordingly, sensing and compensation technology for compensating for variation in characteristic values between circuit elements of sub-pixels is being developed.

The conventional sensing and compensation technology separately uses a sensing line for sensing the characteristic value of the circuit element of the sub-pixel in order to compensate for the deviation of the characteristic value between the circuit elements of the sub-pixel.

Due to the use of such a sensing line, the aperture ratio of the organic light emitting display panel may be lowered and the panel design and process may be complicated.

In addition, the sensing driving (particularly, the threshold voltage sensing driving of the driving transistor) for sensing the characteristic value of the circuit element (organic light emitting diode, driving transistor) of each sub-pixel is performed in real time while the image is displayed on the screen due to the driving characteristics. There are also problems that make it difficult to proceed.

It is an object of the present embodiments to provide a sub-pixel structure that enables sensing driving while deleting an existing sensing line.

Another object of the present embodiments is to simplify the panel design structure and the panel manufacturing process.

Another object of the present embodiments is to sense and compensate the characteristics of circuit elements (organic light emitting diodes and driving transistors) of each sub-pixel in real time while an image is displayed on a screen.

Another object of the present embodiments is not to sense the sensing point for sensing the characteristic of the circuit element of each sub-pixel, but to detect the voltage change of the gate node of the driving transistor coupled to the sensing point that is changed through constant current sensing. It detects and calculates the current flowing through the driving transistor to sense the characteristic value of the circuit element.

In one aspect, the present embodiments provide an organic light emitting display panel in which a plurality of subpixels defined by a plurality of data lines and a plurality of gate lines are arranged, a data driver driving the plurality of data lines, and a plurality of gate lines It is possible to provide an organic light emitting display device including a gate driver for driving the display.

In the organic light emitting diode display, each of the plurality of sub-pixels is controlled by an organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a first scan signal, and is electrically connected between a first node of the driving transistor and a data line. a first transistor connected to A first capacitor may be included.

In addition, the organic light emitting diode display may further include a switch circuit electrically connecting one of a first switch node to which a data voltage is input and a second switching node connected to the analog-to-digital converter to the data line.

When the first switch node and the data line are connected by the switch circuit, the data voltage input to the first switch node may be supplied to the data line.

In addition, when the second switch node and the data line are connected by the switch circuit, the analog-to-digital converter may sense the voltage of the data line.

Also, in the organic light emitting display device, a display driving section and a sensing driving section may be alternately performed during image display.

In another aspect, the present embodiments may provide an organic light emitting display panel in which a plurality of sub-pixels defined by a plurality of data lines and a plurality of gate lines are arranged.

Each subpixel of the organic light emitting display panel is controlled by an organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a first scan signal, and is electrically connected between a first node of the driving transistor and a data line. The first transistor, the second transistor controlled by the second scan signal and electrically connected between the second node and the ground node of the driving transistor, and the second transistor electrically connected between the first node and the second node of the driving transistor 1 may contain a capacitor.

In such an organic light emitting display panel, between the first section in which the organic light emitting diode emits light and the second section in which the organic light emitting diode emits light, the voltage of the first node and the second node of the driving transistor in the non-emission state of the organic light emitting diode This rising section may exist.

In another aspect, a data voltage output unit for outputting a data voltage to the first switch node, an analog-to-digital converter electrically connected to the second switch node, and one of the first switch node and the second switching node are electrically connected to the data line It is possible to provide a source driver integrated circuit including a switch circuit for connecting the .

In such a source driver integrated circuit, when the first switch node and the data line are connected by the switch circuit, the data voltage output unit may supply the data voltage to the data line through the first switch node.

In the source driver integrated circuit, when the second switch node and the data line are connected by the switch circuit, the analog-to-digital converter converts the voltage of the data line into a digital value through the second switch node and outputs the converted digital value. .

In another aspect, the present embodiments may provide a digital-to-analog converter and a method of operating a data driver including the analog-to-digital converter.

The method of operating the data driver includes the steps of electrically connecting a digital-to-analog converter to a data line to output a data voltage to the data line, and electrically connecting the analog-to-digital converter to the data line to convert the voltage of the data line into a digital value. and outputting the converted digital value.

In another aspect, in the present embodiments, a plurality of subpixels are arranged including an organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a switching transistor electrically connected between a gate node of the driving transistor and a data line. A method of driving an organic light emitting display device including an organic light emitting display panel and a data driver driving a data line can be provided.

The driving method of the organic light emitting display device includes a first step of outputting a first data voltage to a data line, a second step of increasing the voltage of the gate node of the driving transistor for a first time, and a gate node of the driving transistor. A third step of first sensing the increased voltage through a data line, a fourth step of outputting a second data voltage to the data line, a fifth step of increasing the voltage of the gate node of the driving transistor for a second time; , a sixth step of secondarily sensing the increased voltage of the gate node of the driving transistor through the data line, the voltage and the first time sensed primarily in the third step, and the voltage and the second sensed second in the sixth step A seventh step of calculating threshold voltage information and mobility information of the driving transistor based on the 3 time period may be included.

According to the present embodiments as described above, it is possible to provide a sub-pixel structure that enables sensing driving while deleting an existing sensing line.

According to the present embodiments, it is possible to simplify the panel design structure and the panel manufacturing process.

According to the present exemplary embodiments, characteristics of circuit elements (organic light emitting diodes and driving transistors) of each sub-pixel may be sensed and compensated in real time while an image is displayed on the screen.

According to the present embodiments, the voltage change of the gate node of the driving transistor coupled to the sensing point changed through constant current sensing is detected, rather than the sensing point for sensing the characteristic of the circuit element of each sub-pixel. It is possible to sense the characteristic value of the circuit element by predicting the current flowing through the driving transistor.

1 is a schematic system configuration diagram of an organic light emitting diode display according to example embodiments.
2 is an exemplary diagram of a sub-pixel circuit of the organic light emitting diode display according to the first embodiment.
3 is an exemplary diagram of a compensation circuit of the organic light emitting diode display according to the first embodiment.
4 is a diagram illustrating a gate driving sequence of the organic light emitting diode display according to the first exemplary embodiment.
5 is a diagram illustrating characteristic curves of a driving transistor and an organic light emitting diode of an organic light emitting diode display according to the present exemplary embodiment.
6 is an example of a sensing driving period of the organic light emitting diode display according to the present embodiments.
7 is an exemplary diagram of a sub-pixel circuit of an organic light emitting diode display according to the second exemplary embodiment.
8 is a view illustrating a display driving section and a sensing driving section of the organic light emitting diode display according to the second exemplary embodiment.
9 is a diagram illustrating a gate driving sequence in a display driving period of a subpixel circuit of an organic light emitting diode display according to the second exemplary embodiment.
10 is a driving timing diagram in a display driving period of a sub-pixel circuit of an organic light emitting diode display according to the second exemplary embodiment.
11 is a diagram illustrating a gate driving sequence in a sensing driving period of a subpixel circuit of an organic light emitting diode display according to the second exemplary embodiment.
12 is a driving timing diagram in a sensing driving period of a sub-pixel circuit of an organic light emitting diode display according to the second exemplary embodiment.
13 is a graph illustrating a voltage change at a second node of a driving transistor in an organic light emitting diode emission period within a display driving period of a subpixel circuit of an organic light emitting diode display according to the second exemplary embodiment.
14 is a graph illustrating a voltage change of a second node of a driving transistor in an organic light emitting diode driving period within a sensing driving period of a subpixel circuit of an organic light emitting diode display according to the second exemplary embodiment.
15 is a diagram illustrating a source driver integrated circuit of an organic light emitting diode display according to a second exemplary embodiment.
16 is a flowchart illustrating a method of operating a source driver integrated circuit of an organic light emitting diode display according to the second exemplary embodiment.
17 is a flowchart illustrating a method of driving an organic light emitting display device according to the second exemplary embodiment.

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 schematic system configuration diagram of an organic light emitting diode display 100 according to the present exemplary embodiments.

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 and a plurality of gate lines are disposed. The organic light emitting display panel 110 in which a plurality of sub pixels (SP) defined by the gate line GL are arranged, the data driver 120 driving the plurality of data lines DL, and the plurality of The gate driver 130 for driving the gate line GL may be included.

Also, the organic light emitting diode display 100 according to the present exemplary embodiments may further include a controller 140 for controlling the data driver 120 and the gate driver 130 .

The controller 140 may supply 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 controller 140 may be implemented as a component separate from the data driver 120 , or may be implemented as an integrated circuit together with the data driver 120 .

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 be implemented by including at least one source driver integrated circuit (SDIC).

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 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 be implemented by including at least one gate driver integrated circuit (GDIC).

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

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.

As shown in FIG. 1 , the data driver 120 may be located only on one side (eg, upper or lower side, or left or right side) of the organic light emitting display panel 110 , and in some cases, a driving method or a panel design method It may be located on both sides (eg, upper and lower sides, or left and right, etc.) of the organic light emitting display panel 110 , depending on the circumstances.

As shown in FIG. 1 , the gate driver 130 may be located only on one side (eg, left or right side or upper side or lower side) of the organic light emitting display panel 110 , and in some cases, a driving method and a panel design. It may be located on both sides (eg, left and right, or upper and lower) of the organic light emitting display panel 110 according to a method or the like.

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 .

Each sub-pixel SP arranged in the organic light emitting display panel 110 includes an organic light emitting diode (OLED), which is a self-emissive element, and a driving transistor for driving the organic light emitting diode (OLED). It is composed of circuit elements such as

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 circuit of the organic light emitting diode display 100 according to the first exemplary embodiment.

Referring to FIG. 2 , in the organic light emitting diode display 100 according to the first embodiment, each sub-pixel SP basically includes an organic light emitting diode (OLED) and a driving device for driving the organic light emitting diode (OLED). A driving transistor (DRT), 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 data voltage corresponding to an image signal voltage or A first capacitor (C1: Storage Capacitor) for maintaining a voltage corresponding thereto for one frame time may be included.

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

A ground voltage EVSS may be applied to the second electrode of the organic light emitting diode OLED.

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

The driving transistor DRT has a first node N1 , a second node N2 , and a third node N3 .

The first node N1 of the driving transistor DRT is a node corresponding to a gate node and may be electrically connected to a source node or a drain node of the first transistor T1 .

The second node N2 of the driving transistor DRT 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 of the driving transistor DRT is a node to which the driving voltage EVDD is applied, and may be electrically connected to a driving voltage line (DVL) that supplies the driving voltage EVDD, and has a drain. It can be a node or a source node.

The driving transistor DRT and the first transistor T1 may be implemented as an n-type or a p-type as in the example of FIG. 2 .

The first transistor T1 is electrically connected between the data line DL and the first node N1 of the driving transistor DRT, and is controlled by receiving the first scan signal SCAN1 as a gate node through the gate line. can be

The first transistor T1 is turned on by the first scan signal SCAN1 to transfer the data voltage Vdata supplied from the data line DL to the first node N1 of the driving transistor DRT. can

The first capacitor C1 may be electrically connected between the first node N1 and the second node N2 of the driving transistor DRT.

The first capacitor C1 is not a parasitic capacitor (eg, Cgs, Cgd) which is an internal capacitor existing between the first node N1 and the second node N2 of the driving transistor DRT. , an external capacitor intentionally designed outside the driving transistor DRT.

On the other hand, in the case of the organic light emitting diode display 100 , as the driving time of each subpixel SP increases, deterioration of circuit elements such as the organic light emitting diode OLED and the driving transistor DRT is progressed. can

Accordingly, a unique characteristic value of a circuit element such as an organic light emitting diode (OLED) or a driving transistor (DRT) may change. Here, the intrinsic characteristic value of the circuit element may include a threshold voltage of the organic light emitting diode (OLED), a threshold voltage of the driving transistor (DRT), mobility of the driving transistor (DRT), and the like.

A change in a characteristic value of a circuit element may cause a change in luminance of a corresponding sub-pixel. Accordingly, the change in the characteristic value of the circuit element can be used in the same concept as the change in the luminance of the sub-pixel.

In addition, the degree of change in the characteristic value between the circuit elements may be different from each other according to the difference in the degree of deterioration of each circuit element.

The difference in the degree of change in the characteristic value between the circuit elements may cause a deviation in the characteristic value between the circuit elements, which may cause a luminance deviation between sub-pixels. Accordingly, the characteristic value deviation between circuit elements may be used as the same concept as the luminance deviation between sub-pixels.

A change in the characteristic value of a circuit element (change in the luminance of sub-pixels) and a deviation in the characteristic value between circuit elements (a luminance deviation between sub-pixels) cause problems such as lowering the accuracy of the luminance expression of the sub-pixels or causing screen abnormalities. can do it

The organic light emitting display device 100 according to the present exemplary embodiments may provide a sensing function for sensing a characteristic value of a sub-pixel and a compensation function for compensating for a characteristic value of the sub-pixel by using the sensing result.

In the present specification, sensing the characteristic value of the sub-pixel means sensing a characteristic value or a change in characteristic value of a circuit element (driving transistor (DRT), organic light-emitting diode (OLED)) in the sub-pixel, or a circuit element (driving transistor ( DRT) and organic light emitting diode (OLED)) may mean sensing a characteristic value deviation.

In the present specification, compensating for a characteristic value of a sub-pixel means making a characteristic value or a characteristic value change of a circuit element (a driving transistor (DRT), an organic light emitting diode (OLED)) in the sub-pixel to a predetermined level, or making a circuit element (driving It may mean reducing or eliminating the characteristic value deviation between the transistor (DRT) and the organic light emitting diode (OLED).

The organic light emitting diode display 100 according to the present exemplary embodiments may include a sub-pixel circuit (sub-pixel structure) suitable for providing a sensing function and a compensation function, and a compensation circuit including a sensing and compensation structure. have.

Accordingly, as shown in FIG. 2 , each subpixel disposed in the organic light emitting display panel 110 according to the first exemplary embodiment includes, for example, an organic light emitting diode (OLED), a driving transistor (DRT), and a first transistor. In addition to T1 and the first capacitor C1, a second transistor T2 may be further included.

Referring to FIG. 2 , the second transistor T2 is electrically connected between the second node N2 of the driving transistor DRT and a reference voltage line (RVL) supplying a reference voltage (Vref). , and may be controlled by receiving the second scan signal SCAN2 as a gate node.

By further including the above-described second transistor T2 , the voltage state of the second node N2 of the driving transistor DRT in the subpixel SP may be effectively controlled.

The second transistor T2 is turned on by the second scan signal SCAN2 to apply the reference voltage Vref supplied through the reference voltage line RVL to the second node N2 of the driving transistor DRT. approve it

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.

Meanwhile, the first scan signal SCAN1 and the second scan signal SCAN2 may be separate gate signals. In this case, the first scan signal SCAN1 and the second scan signal SCAN2 are respectively applied to the gate node of the first transistor T1 and the gate node of the second transistor T2 through different gate lines. may be

In some cases, the first scan signal SCAN1 and the second scan signal SCAN2 may be the same gate signal. In this case, the first scan signal SCAN1 and the second scan signal SCAN2 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. .

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

Referring to FIG. 3 , the organic light emitting diode display 100 according to the first exemplary embodiment includes an analog-to-digital converter (ADC) that generates and outputs sensed data through voltage sensing in order to identify a characteristic value of a sub-pixel, and an analog The digital converter (ADC) may include a compensating unit 300 that performs a compensation process for compensating for the characteristic value of the sub-pixel based on the characteristic value of the sub-pixel by using the sensed data output, and the like, It may further include a memory (not shown) for storing the sensing data and for storing the compensation value calculated according to the compensation processing result.

For example, an analog-to-digital converter (ADC) may be included in each source driver integrated circuit (SDIC) implementing the data driver 120 , and in some cases, the source driver integrated circuit (SDIC) may be included outside of

The compensator 300 may be included inside the controller 140 , and in some cases, may be included outside the controller 140 .

The sensing data output from the analog-to-digital converter (ADC) may be, for example, in a low voltage differential signaling (LVDS) data format.

Referring to FIG. 3 , the organic light emitting diode display 100 according to the present exemplary embodiments includes an initialization switch SPRE that controls whether a reference voltage Vref is applied to a reference voltage line RVL, and a reference voltage line. It may include a sampling switch (SAM) that controls whether the connection between the (RVL) and the analog-to-digital converter (ADC) is made.

The initialization switch SPRE is driven so that the second node N2 of the driving transistor DRT in the subpixel SP enters a voltage state that reflects a desired characteristic value of a circuit element (a characteristic value of the driving transistor or organic light emitting diode). A switch for controlling a voltage application state of the second node N2 of the transistor DRT.

When the initialization switch SPRE is turned on, the reference voltage Vref is supplied to the reference voltage line RVL through the turned-on second transistor T2 to the second node N2 of the driving transistor DRT. ) can be approved.

The sampling switch SAM is turned on and electrically connects the reference voltage line RVL and the analog-to-digital converter ADC.

The sampling switch SAM has an on-off timing such that it is turned on when the second node N2 of the driving transistor DRT in the subpixel SP reaches a voltage state that reflects the desired characteristic value of the circuit element. Controlled.

When the sampling switch SAM is turned on, the analog-to-digital converter ADC may sense the voltage of the connected reference voltage line RVL.

When the analog-to-digital converter ADC senses the voltage of the reference voltage line RVL, when the second transistor T2 is turned on, if the resistance component of the driving transistor DRT can be ignored, the analog-to-digital converter The voltage sensed by the ADC may correspond to the voltage of the second node N2 of the driving transistor DRT.

The voltage sensed by the analog-to-digital converter ADC may correspond to the voltage of the reference voltage line RVL, that is, the voltage of the second node N2 of the driving transistor DRT.

Also, the voltage of the second node N2 of the driving transistor DRT may correspond to the voltage of the first electrode of the organic light emitting diode OLED.

If a line capacitor is present on the reference voltage line RVL, the voltage sensed by the analog-to-digital converter ADC may be a voltage charged in the line capacitor on the reference voltage line RVL.

Here, the reference voltage line RVL is also referred to as a sensing line.

For example, the voltage sensed by the analog-to-digital converter (ADC) is a voltage value (Vdata-Vth or Vdata-ΔVth) including a threshold voltage (Vth) or a threshold voltage deviation (ΔVth) of the driving transistor (DRT), where: Vdata is a data voltage for sensing driving) or a voltage value for sensing the mobility of the driving transistor DRT.

Meanwhile, as an example, one reference voltage line RVL may be disposed in each subpixel column, or may be disposed in each of two or more subpixel columns.

For example, if one pixel is composed of 4 sub-pixels (red sub-pixel, white sub-pixel, green sub-pixel, and blue sub-pixel), the reference voltage line RVL has 4 sub-pixel columns (red sub-pixel columns). , one for each pixel column including a white subpixel column, a green subpixel column, and a blue subpixel column).

As such, in the case of the organic light emitting diode display 100 according to the first embodiment, since the reference voltage RVL must be disposed for sensing the characteristic value of the driving transistor DRT or the organic light emitting diode OLED, the organic light emitting display The design of the panel 110 may be complicated and the aperture ratio may also be reduced.

4 is a diagram illustrating a gate driving sequence of the organic light emitting diode display 100 according to the first exemplary embodiment. However, this is a case in which the first scan signal SCAN1 and the second scan signal SCAN2 are individually controlled.

Meanwhile, the first scan signal SCAN1 may have a turn-on level voltage for turning on the first transistor T1, and a turn-off level voltage for turning off the first transistor T1. may have

In addition, the second scan signal SCAN2 may have a turn-on level voltage for turning on the second transistor T2, and a turn-off level voltage for turning off the second transistor T2. may have

Depending on the transistor type (n-type or p-type), in each of the scan signals SCAN1 and SCAN2, the turn-on level voltage may be a high level voltage or a low level voltage, and the turn-off level voltage may be a low level voltage or a high level voltage. It may be a level voltage.

Hereinafter, for convenience of description, a case in which a turn-on level voltage is a high level voltage and a turn-off level voltage is a low level voltage in each of the scan signals SCAN1 and SCAN2 will be described as an example.

Referring to FIG. 4 , during the display driving period (normal driving period), the first scan signal SCAN1 and the second scan signal SCAN2 are turned-on level voltages (eg, high level) in the same period or overlapping period. voltage) and may be changed to a turn-off level voltage (eg, a low level voltage).

During the display driving period (the normal driving period), the organic light emitting diode OLED may emit light in a period in which the first scan signal SCAN1 and the second scan signal SCAN2 have turn-off level voltages.

Referring to FIG. 4 , during a driving period (eg, an OLED characteristic sensing driving period) for sensing a characteristic value (eg, a threshold voltage) of the organic light emitting diode (OLED), the first scan signal SCAN1 is a turn-off level voltage (eg, : It is changed from low level voltage) to turn-on level voltage (eg high level voltage).

During the period in which the first scan signal SCAN1 has the turn-on level voltage, the second scan signal SCAN2 is changed to the turn-on level voltage and then changed back to the turn-off level voltage.

And, when the first scan signal SCAN1 is changed to a turn-off level voltage, the second scan signal SCAN2 is changed to a turn-on level voltage once more and then changed to a turn-off level voltage again.

During the OLED characteristic sensing driving period illustrated in FIG. 4 , the waveform change of the first scan signal SCAN1 and the second scan signal SCAN2 is only an example, and the second node N2 of the driving transistor DRT emits organic light. If only the voltage of the second node N2 of the driving transistor DRT can be sensed after allowing the characteristic value of the diode OLED (eg, characteristic value related to the degree of deterioration such as the threshold voltage) to be reflected , the gate driving sequence may be variously modified.

Referring to FIG. 4 , a first scan signal SCAN1 and a second scan signal during a driving period (DRT characteristic value Φ sensing driving period) for sensing pi (Φ) related to a threshold voltage among characteristic values of the driving transistor DRT SCAN2 may have a turn-on level voltage (eg, a high level voltage) in the same section or an overlapping section and then change to a turn-off level voltage (eg, a low level voltage).

During the DRT characteristic value Φ sensing driving period illustrated in FIG. 4 , the waveform change of the first scan signal SCAN1 and the second scan signal SCAN2 is only an example, and the second node N2 of the driving transistor DRT is driven After allowing the threshold voltage to be reflected among the characteristic values of the transistor DRT, if only the voltage of the second node N2 of the driving transistor DRT can be sensed, the gate driving sequence can be variously modified. have.

During the DRT characteristic value Φ sensing driving period, the second node N2 of the driving transistor DRT is in a floating state and a period in which the voltage rises is required.

Accordingly, while the first scan signal SCAN1 has the turn-on level voltage, the second scan signal SCAN2 may change from the turn-on level voltage to the turn-off level voltage. Accordingly, the second node N2 of the driving transistor DRT may be in a floating state so that the voltage may increase, and the voltage may be saturated during the rise.

Of course, during the DRT characteristic value Φ sensing driving period, during the period in which the first scan signal SCAN1 has the turn-on level voltage, the second scan signal SCAN2 may also have the turn-on level voltage. In this case, in order to float the second node N2 of the driving transistor DRT, the initialization switch SRPE may be turned off.

Referring to FIG. 4 , during a driving period (DRT characteristic value α sensing driving period) for sensing alpha (α) related to mobility among characteristic values of the driving transistor DRT, a first scan signal SCAN1 and a second scan signal ( SCAN2) is also changed to the turn-on level voltage, only the first scan signal SCAN1 is changed to the turn-off level voltage, and then, after a predetermined time has elapsed, the second scan signal SCAN2 is also turned off It can be changed to a level voltage.

During the DRT characteristic value α sensing driving period illustrated in FIG. 4 , the waveform change of the first scan signal SCAN1 and the second scan signal SCAN2 is only an example, and the second node N2 of the driving transistor DRT is driven The gate driving sequence may be variously modified if only the voltage of the second node N2 of the driving transistor DRT can be sensed after the mobility among the characteristic values of the transistor DRT can be detected. .

During the DRT characteristic value α sensing driving period, the second node N2 of the driving transistor DRT is in a floating state and a period in which the voltage rises is required.

Accordingly, when the first scan signal SCAN1 is changed to the turn-off level voltage, the second scan signal SCAN2 may also be changed to the turn-off level voltage. Accordingly, the second node N2 of the driving transistor DRT may be in a floating state and a voltage may increase.

After the voltage of the second node N2 of the driving transistor DRT rises for a predetermined time, the voltage of the second node N2 of the driving transistor DRT is sensed, and the driving transistor DRT is based on the sensed voltage. mobility can be observed.

Of course, during the DRT characteristic value α sensing driving period, in the period in which the second scan signal SCAN2 has a turn-on level voltage, if it is desired to float the second node N2 of the driving transistor DRT, the initialization switch ( SRPE) may be turned off to make the second node N2 of the driving transistor DRT float.

The threshold voltage and mobility of the above-described driving transistor DRT are sensed and compensated through a separate sensing driving.

5 is a diagram illustrating characteristic curves of a driving transistor DRT and an organic light emitting diode OLED of the organic light emitting diode display 100 according to the present exemplary embodiments.

The threshold voltage and mobility of the driving transistor DRT may be sensed and compensated for through individual sensing driving.

The current equation of the driving transistor DRT may be expressed as Equation 1 below.

In Equation 1, Isat is a current flowing through the driving transistor DRT, Vdata is a data voltage for sensing driving, and Vs is a voltage of the second node (N2, in the case of a source node) of the driving transistor DRT, Φ is a component related to the threshold voltage of the driving transistor DRT, and α is a component related to the mobility of the driving transistor DRT.

Referring to FIG. 5 , the driving transistor DRT and the organic light emitting diode OLED have characteristic curves that are correlated with each other. Sensing and compensating for the characteristic value of DRT should be performed after the sensing and compensation of the characteristic value of the driving transistor DRT is completed.

6 are examples of a sensing driving period of the organic light emitting display device 100 according to the present exemplary embodiments.

Referring to FIG. 6 , in the organic light emitting diode display 100 according to the present exemplary embodiments, when a power-on signal is generated, the characteristic value of the driving transistor DRT in each sub-pixel disposed in the organic light emitting display panel 110 is obtained. can sense This sensing process is called "On-Sensing Process".

In addition, when a power-off signal is generated, the characteristic value of the driving transistor DRT in each sub-pixel disposed in the organic light emitting display panel 110 is sensed before an off-sequence such as power-off is performed. may be Such a sensing process is referred to as an "off-sensing process".

In addition, after the power-on signal is generated, the characteristic value of the driving transistor DRT in each sub-pixel disposed in the organic light emitting display panel 110 may be sensed every blank time during display driving. Such a sensing process is referred to as a "real-time sensing process".

The real-time sensing process may be performed at each blank time between active times based on the vertical synchronization signal Vsync.

According to the first embodiment, since the threshold voltage sensing Vth of the driving transistor DRT requires a voltage saturation time of the second node N2 of the driving transistor DRT, movement of the driving transistor DRT is required. Compared to mobility sensing, it takes a relatively long time.

In consideration of this, according to the first embodiment, for example, the threshold voltage sensing of the driving transistor DRT may be performed while the display is not driven after a power-off signal is generated according to a user input or the like.

That is, the threshold voltage sensing of the driving transistor DRT may be performed through an off-sensing process.

Meanwhile, according to the first embodiment, for example, sensing the mobility of the driving transistor DRT may be performed even after the power-off signal is generated, but considering that it takes a short time, before the display driving starts or It can be performed in real time even while the display is being driven.

That is, the mobility sensing of the driving transistor DRT may be performed as an on-sensing process before a power-on signal is generated and the display starts driving, or a real-time sensing process every blank time during display driving. (Real-Time Sensing Process).

In the case of the organic light emitting display device 100 according to the first embodiment, for the purpose of compensating for characteristics of the organic light emitting diode (OLED) and the driving transistor (DRT), user convenience decreases, panel design difficulty increases, and panel aperture ratio decreases can cause etc.

Accordingly, in the present specification, a function of sensing and compensating the characteristic values of the organic light emitting diode (OLED) and the driving transistor (DRT) is provided in real time during driving, and the characteristic change of the circuit elements (OLED, DRT) is compensated for in real time, A second embodiment capable of reducing the panel design difficulty and increasing the panel opening ratio is provided.

7 is an exemplary diagram of a sub-pixel circuit of the organic light emitting diode display 100 according to the second exemplary embodiment.

Referring to FIG. 7 , in the organic light emitting diode display 100 according to the second embodiment, each of the plurality of sub-pixels SP defined by the plurality of data lines DL and the plurality of gate lines GL includes: It may include an organic light emitting diode (OLED), a driving transistor (DRT), a first transistor (T1), a second transistor (T2), a first capacitor (C1), and the like.

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

Here, the first electrode is an electrode electrically connected to a source node or a drain node of the driving transistor DRT, and may be an anode electrode or a cathode electrode. The second electrode is an electrode to which the ground voltage EVSS is applied, and may be a cathode electrode or an anode electrode.

The driving transistor DRT is a transistor for driving the organic light emitting diode OLED, and may include a first node N1 , a second node N2 , and a third node N3 .

The first node N1 of the driving transistor DRT may be a gate node.

The second node N2 of the driving transistor DRT may be a source node or a drain node, and may be electrically connected to the first electrode of the organic light emitting diode OLED.

The third node N3 of the driving transistor DRT may be a drain node or a source node, and may be electrically connected to the driving voltage line DVL and to which the driving voltage EVDD may be applied.

The first transistor T1 is turned on or off by the first scan signal SCAN1 , and may be electrically connected between the first node N1 of the driving transistor DRT and the data line DL.

That is, the drain node or the source node of the first transistor T1 is electrically connected to the data line DL, and the source node or the drain node of the first transistor T1 is the first node N1 of the driving transistor DRT. ) can be electrically connected to.

The first transistor T1 is turned on to transfer the data voltage Vdata to the first node N1 of the driving transistor DRT.

The second transistor T2 is controlled on-off by the second scan signal SCAN2 and may be electrically connected between the second node N2 of the driving transistor DRT and the ground node GND.

That is, the drain node or source node of the second transistor T2 is electrically connected to the ground node GND, and the source node or the drain node of the ground node GND is the second node N2 of the driving transistor DRT. ) can be electrically connected to.

The first capacitor C1 is electrically connected between the first node N1 and the second node N2 of the driving transistor DRT, and serves to maintain a constant voltage for a predetermined time (eg, one frame time). It may be a storage capacitor that does

As described above, the sub-pixel circuit according to the second embodiment is different from the sub-pixel circuit according to the first embodiment, and the reference voltage line RVL is electrically connected to the drain node or the source node of the second transistor T2. ) does not exist. As a result, the number of signal wirings in the organic light emitting display panel 110 is reduced, so that the panel design and manufacturing process can be simplified, and the panel aperture ratio can be increased.

Meanwhile, the driving transistor DRT, the first transistor T1 , and the second transistor T2 may be an n-type transistor or a p-type transistor.

The first capacitor C1 is not a parasitic capacitor (eg, Cgs, Cgd) which is an internal capacitor existing between the first node N1 and the second node N2 of the driving transistor DRT. , an external capacitor intentionally designed outside the driving transistor DRT.

Meanwhile, the second capacitor component C2 may be present in the first electrode (eg, an anode electrode) of the organic light emitting diode (OLED).

Referring to FIG. 7 , in the organic light emitting display device 1000 according to the second embodiment, a first switch node Na to which a data voltage Vdata is input and a second switching node Nb connected to the analog-to-digital converter ADC ) may include a switch circuit 700 electrically connecting one of them to the data line DL.

Such a switch circuit 700 may be included in the data driver 120 .

That is, the switch circuit 700 may be included in the source driver integrated circuit SDIC implementing the data driver 120 .

The switch circuit 700 may connect the first switch node Na and the data line DL at a required time in the display driving period or the sensing driving period.

The switch circuit 700 may connect the second switch node Nb and the data line DL at a necessary time in the sensing driving period.

Referring to FIG. 7 , when the first switch node Na and the data line DL are connected by the switch circuit 700 , data input from the data voltage output unit VOUT to the first switch node Na The voltage Vdata may be supplied to the data line DL.

Referring to FIG. 7 , when the second switch node Nb and the data line DL are connected by the switch circuit 700 , the analog-to-digital converter ADC senses the voltage Vsen of the data line DL. can do.

In the switch circuit 700 , a switching operation may be controlled by the controller 140 .

On the other hand, the switch circuit 700 illustrated in FIG. 7 is implemented with one switch, and alternatively, it may be configured with two switches.

That is, the switch circuit 700 includes a first switch (not shown) for controlling the connection between the first switch node Na connected to the data voltage output unit VOUT and the data line DL, and the analog-to-digital converter ADC. ) may be configured to include a second switch (not shown) for controlling the connection between the second switch node Nb connected to the data line DL and the data line DL.

Meanwhile, the data voltage output unit VOUT may be a digital-to-analog converter (DAC) or an output buffer for outputting an analog voltage output from the digital-to-analog converter (DAC).

When the analog-to-digital converter ADC senses the voltage Vsen of the data line DL, it may mean that the voltage Vsen of the data line DL is converted to a digital value.

The analog-to-digital converter (ADC) outputs the converted digital value (sensing value).

A digital value (sensed value) output from the analog-to-digital converter ADC may be transmitted to the compensator 710 or stored in a memory (not shown).

The compensator 710 performs a compensation process of calculating a compensation value for compensating for a characteristic value of a driving transistor (DRT) or an organic light emitting diode (OLED) based on a digital value (sensed value) transmitted or stored in a memory. can do.

The compensator 710 has a configuration corresponding to that of the compensator 300 of FIG. 3 .

According to the above-described switch circuit 700 , the data line DL may serve as a data voltage transfer path and as a voltage sensing path. That is, by the switch circuit 700 , the data line DL may serve as a data voltage transfer path at one point in time and serve as a voltage sensing path at another time point.

8 is a diagram illustrating a display driving section and a sensing driving section of the organic light emitting display device 100 according to the second exemplary embodiment.

Referring to FIG. 8 , the organic light emitting display device 100 according to the second embodiment may perform sensing driving in real time during display driving.

That is, in the organic light emitting diode display 100 according to the second embodiment, before the power-off signal is generated, the display driving period and the sensing driving period may be alternately performed.

Here, the sensing driving includes a threshold voltage sensing driving of the driving transistor DRT (DRT characteristic value Φ sensing driving), a mobility sensing driving of the driving transistor DRT (DRT characteristic α sensing driving), and an organic light emitting diode (OLED). It may include at least one of organic light emitting diode characteristic value sensing driving (OLED characteristic value sensing driving) for sensing a characteristic value (eg, a threshold voltage) of .

As described above, by performing sensing driving during image display, that is, sensing driving in real time, there is an advantage in that it is not necessary to spend a separate time for sensing driving after the power-off signal is generated.

When the sensing driving is performed after the power-off signal is generated, there is a problem in that the sensing driving is not normally performed due to the user's act of unplugging the power cable.

However, when sensing driving is performed in real time, there is also an advantage of stably performing sensing driving.

9 is a diagram illustrating a gate driving sequence in a display driving section of a sub-pixel circuit of the organic light emitting diode display 100 according to the second embodiment, and FIG. 10 is the organic light emitting display device 100 according to the second embodiment. It is a driving timing diagram in the display driving period of the sub-pixel circuit of . However, hereinafter, for convenience of description, it is assumed that the first node N1 of the driving transistor DRT is a gate node and the second node N2 of the driving transistor DRT is a source node.

9 and 10 , the display driving section may include a preparation section S910 , a data input section S920 , and an organic light emitting diode light emitting section S930 .

9 and 10 , during the preparation period S910 , the first scan signal SCAN1 and the second scan signal SCAN2 are turn-off level voltages.

9 and 10 , during the data input period S920 , the first scan signal SCAN1 and the second scan signal SCAN2 may be changed to turn-on level voltages.

During the data input period S920 , the switch circuit 700 may connect the data line DL and the first switch node Na.

Accordingly, the data voltage Vdata1 is supplied to the data line DL. In addition, the data voltage Vdata1 supplied to the data line DL may be applied to the first node N1 of the driving transistor DRT through the turned-on first transistor T1 .

Accordingly, during the data input period S920 , the voltage Vg at the gate node of the driving transistor DRT may become the data voltage Vdata1 .

Also, during the data input period S920 , the second transistor T2 is turned on by the second scan signal SCAN2 of the turn-on level voltage, and through the second transistor T2 , the ground node GDN ) may be the ground voltage and the voltage Vs of the source node of the driving transistor DRT may be the ground voltage.

9 and 10 , during the organic light emitting diode emission period S930 , the first scan signal SCAN1 and the second scan signal SCAN2 are changed to a turn-off level voltage.

Accordingly, the gate voltage Vg and the source voltage Vs of the driving transistor DRT increase while maintaining a voltage difference.

When a predetermined time elapses after the voltage rise, when the source voltage Vs of the driving transistor DRT becomes a voltage state at which current can flow through the organic light emitting diode OLED, that is, the organic light emitting diode turn-on voltage or higher In this case, current flows to the organic light emitting diode (OLED), so that the organic light emitting diode (OLED) can emit light.

The sub-pixel circuit (sub-pixel structure) according to the second embodiment shown in FIG. 7 may also enable normal display driving.

11 is a diagram illustrating a gate driving sequence in a sensing driving period of a sub-pixel circuit of the organic light emitting diode display 100 according to the second embodiment, and FIG. 12 is the organic light emitting display device 100 according to the second embodiment. It is a driving timing diagram in the sensing driving period of the sub-pixel circuit of .

Referring to FIGS. 11 and 12 , a sensing driving period that proceeds after the organic light emitting diode light emitting period S930 of the display driving period is performed.

That is, the sensing driving section proceeds between the organic light emitting diode light emitting section (S930) of the display driving section and the preparation section (S910) of the display driving section, the organic light emitting diode characteristic sensing section (S1020), the discharging section (S1030), and charging It may include a section S1040, an organic light emitting diode driving section S1050, and a driving transistor characteristic sensing section S1060.

In addition, after the driving transistor characteristic sensing period ( S1060 ), a preparation period ( S910 ) of the display driving period may proceed.

Meanwhile, the organic light emitting diode light emitting section S930 of the display driving section and the preparation section S910 of the display driving section may be regarded as including the sensing driving section.

In this case, the organic light emitting diode emission section S930 of the display driving section may be referred to as the sensing driving preparation section S1010 of the sensing driving section. Also, the preparation section S910 of the display driving section may be referred to as the sensing driving end section S1070 of the sensing driving section.

Briefly describing the switching operation of the switch circuit 700 during the sensing driving period, during the organic light emitting diode characteristic sensing period S1020 and the driving transistor characteristic sensing period S1060, the switch circuit 700 is connected to the data line DL. and the second switch node Nb. And, during the charging period ( S1040 ), the switch circuit 700 connects the data line DL and the first switch node Na.

During the discharge period S1030 and the organic light emitting diode driving period S1050 , the switch circuit 700 may connect any of the first switch node Na and the second switch node Nb to the data line DL. Also, it is not necessary to connect the first switch node Na and the second switch node Nb to the data line DL.

11 and 12 , during the organic light emitting diode characteristic sensing period S1020 , the first scan signal SCAN1 is a turn-on level voltage, and the second scan signal SCAN2 is a turn-off level voltage.

During the organic light emitting diode characteristic sensing period S1020 , the switch circuit 700 does not connect the first switch node Na and the data line DL.

Accordingly, the data line DL corresponds to the voltage Vg of the gate node N1 of the driving transistor DRT.

The voltage Vg of the gate node N1 of the driving transistor DRT is displayed in the data voltage Vdata1 applied to the gate node N1 of the driving transistor DRT in the data input period S920 of the display driving period. It may be a voltage obtained by adding a voltage change amount (ΔV=Vs-ground voltage=Vs) of the gate node N1 and the source node N2 of the driving transistor DRT during the organic light emitting diode emission period S930 of the driving period.

That is, the voltage (Vdata1+Vs) of the data line DL in the organic light emitting diode characteristic sensing period S1020 is higher than the voltage Vdata1 of the data line DL in the data input period S920 of the display driving period. During the light emitting period S930 of the light emitting diode, the voltage change amount of the gate node N1 and the source node N2 of the driving transistor DRT may be as high as ΔV=Vs-ground voltage=Vs.

Accordingly, during the organic light emitting diode characteristic sensing period ( S1020 ), the voltage state of the first electrode (anode electrode) of the organic light emitting diode (OLED) reflecting the degree of deterioration (the degree of afterimage) of the organic light emitting diode (OLED) is the data line. (DL) can be reflected.

Meanwhile, during the organic light emitting diode characteristic sensing period ( S1020 ), the data line DL has a fairly large capacitor component. Accordingly, it may appear that the gate voltage Vg and the source voltage Vs of the driving transistor DRT do not increase.

During the organic light emitting diode characteristic sensing period ( S1020 ), at a certain point in time, the switch circuit 700 may connect the second switch node Nb and the data line DL.

Accordingly, the analog-to-digital converter ADC may sense the voltage Vdata1+Vs of the data line DL.

The sensed voltage (Vdata1+Vs) may reflect the degree of deterioration of the organic light emitting diode (OLED) (ie, the degree of generating an afterimage on the screen).

The compensator 710 predicts Vs from the digital value of the voltage (Vdata1+Vs) sensed by the analog-to-digital converter (ADC), and can determine the degree of deterioration (that is, the residual image) of the organic light emitting diode (OLED) from this. have.

That is, the compensator 710 receives the driving transistor (Vdata1+ΔV=Vdata1+Vs-ground voltage=Vdata1+Vs) from the voltage (Vdata1+ΔV=Vdata1+Vs-ground voltage=Vdata1+Vs) sensed by the analog-to-digital converter (ADC) in the organic light emitting diode characteristic sensing period S1020. The voltage change amount of the first node N1 of the DRT is calculated, and the voltage change amount (ΔV=Vs-ground voltage=Vs) of the second node N2 of the driving transistor DRT is predicted based on this. The degree of deterioration (ie, the degree of afterimage) of the light emitting diode (OLED) can be grasped.

As described above, the organic light emitting diode display 100 according to the second exemplary embodiment may determine the degree of deterioration (ie, the afterimage degree) of the organic light emitting diode OLED even through the voltage sensing of the data line DL.

11 and 12 , during the discharging period S1030 , the first scan signal SCAN1 is a turn-off level voltage, and the second scan signal SCAN2 is a turn-on level voltage.

Also, during the discharge period S1030 , the voltage of the first electrode (anode electrode) of the organic light emitting diode OLED, that is, the voltage Vs of the source node of the driving transistor DRT may be discharged.

Also, during the discharging period S1030 , the switch circuit 700 may connect the data line DL and the first switch node Na.

Accordingly, the data voltage Vdata2 may be applied to the data line DL.

11 and 12 , during the charging period S1040 , the first switch node Na and the data line DL are connected by the switch circuit 700 .

As described above, the first switch node Na and the data line DL may be connected during the discharging period S1030 or the charging period S1040 .

During the charging period S1040 , the first scan signal SCAN1 is a turn-on level voltage, and the second scan signal SCAN2 is a turn-on level voltage.

Accordingly, the voltage Vg of the gate node N1 of the driving transistor DRT may become the corresponding data voltage Vdata2.

Here, the gate voltage (Vg=Vdata2) of the driving transistor DRT may be a data voltage capable of compensating for a degree of deterioration (ie, an afterimage degree) of the organic light emitting diode (OLED).

During the charging period S1040 , the corresponding data voltage Vdata2 and the ground voltage are respectively applied to the gate node N1 and the source node N2 of the driving transistor DRT, so that the first capacitor C1 is charged.

That is, during the charging period S1040 , the potential difference between the gate node N1 and the source node N2 of the driving transistor DRT is fixed to the corresponding data voltage (Vdata2-ground voltage=Vdata2).

11 and 12 , during the organic light emitting diode driving period S1050 , the first scan signal SCAN1 may be a turn-off level voltage, and the second scan signal SCAN2 may be a turn-off level voltage. .

Accordingly, both the gate node N1 and the source node N2 of the driving transistor DRT are floated, maintaining the potential difference Vdata2 between the gate node N1 and the source node N2 of the driving transistor DRT. , the gate voltage Vg and the source voltage Vs of the driving transistor DRT increase simultaneously.

11 and 12 , during the driving transistor characteristic sensing period S1060 , the first scan signal SCAN1 is a turn-on level voltage, and the second scan signal SCAN2 is a turn-off level voltage.

During the driving transistor characteristic sensing period S1060 , the first transistor T1 is turned on by the first scan signal SCAN1 of the turn-on level voltage, and the data line DL is connected to the driving transistor DRT. may correspond to the voltage Vg of the gate node N1 of

Here, the voltage of the data line DL corresponding to the voltage Vg of the gate node N1 of the driving transistor DRT is applied to the gate node N1 of the driving transistor DRT in the charging period S1040. A voltage obtained by adding the data voltage Vdata2 and the increase in voltage variation (ΔV=Vs-ground voltage=Vs) of the source node N2 and the gate node N1 of the driving transistor DRT during the organic light emitting diode driving period S1050 . It may correspond to (Vdata2+Vs).

Accordingly, the voltage Vdata2+ΔV=Vdata2+Vs of the data line DL during the driving transistor characteristic sensing period S1060 may be higher than the voltage Vdata2 of the data line DL during the charging period S1040. have.

Accordingly, during the driving transistor characteristic sensing period S1060 , the voltage Vs of the source node N2 of the driving transistor DRT through which the characteristic value of the driving transistor DRT can be grasped is the gate node of the driving transistor DRT. It may be reflected in the data line DL through (N1).

During the driving transistor characteristic sensing period S1060 , the switch circuit 700 may connect the second switch node Nb and the data line DL.

The switch circuit 700 may connect the data line DL to the second switch node Nb in advance during the organic light emitting diode driving period S1050 .

During the driving transistor characteristic sensing period S1060 , the second switch node Nb and the data line DL are connected by the switch circuit 700 , so that the analog-to-digital converter ADC senses the voltage of the data line DL. can do.

At this time, the voltage (Vdata2+Vs) sensed by the analog-to-digital converter (ADC) includes a voltage change amount (ΔV=Vs-ground voltage=Vs) that is increased during the organic light emitting diode driving period ( S1050 ).

The compensator 710 receives the voltage (Vdata2+ΔV=Vdata2+Vs) sensed by the analog-to-digital converter ADC during the driving transistor characteristic sensing period S1060 of the first node N1 of the driving transistor DRT. A voltage change (ΔV=Vs-ground voltage=Vs) is detected (calculated), and a voltage change (ΔV=Vs-ground voltage=Vs) of the second node N2 of the driving transistor DRT is predicted (calculated) from this. )can do.

As described above, in the organic light emitting diode display 100 according to the second exemplary embodiment, the characteristics of the driving transistor DRT can also be detected through the voltage sensing of the data line DL.

The organic light emitting diode emission section S930 within the display driving section and the organic light emitting diode driving section S1050 within the sensing driving section having similar driving characteristics will be described again with reference to FIGS. 13 and 14 .

13 is a diagram illustrating a second node N2 (source node) of the driving transistor DRT in an organic light emitting diode emission period S930 within a display driving period of a subpixel circuit of the organic light emitting diode display 100 according to the second exemplary embodiment. It is a graph showing the voltage change.

Referring to FIG. 13 , during the organic light emitting diode emission period S930 within the display driving period, the voltage Vs of the source node corresponding to the second node N2 of the driving transistor DRT increases, as described above. do.

When the voltage Vs of the source node of the driving transistor DRT is equal to or greater than the turn-on voltage Vf of the organic light emitting diode OLED, the organic light emitting diode OLED is turned on and starts to emit light.

14 illustrates a voltage change at the second node N2 of the driving transistor DRT in the organic light emitting diode driving period S1050 within the sensing driving period of the subpixel circuit of the organic light emitting diode display 100 according to the second exemplary embodiment. is the graph shown.

Referring to FIG. 14 , during the organic light emitting diode driving period S1050 within the sensing driving period, the voltage Vs of the source node corresponding to the second node N2 of the driving transistor DRT increases, as described above. do.

Unlike the organic light emitting diode light emitting section S930, in the organic light emitting diode driving section S1050 within the sensing driving section, the organic light emitting diode (OLED) is not emitted for sensing the characteristic value of the driving transistor DRT, and the driving transistor Change the voltage (Vs) of the source node of (DRT).

Accordingly, during the organic light emitting diode driving period S1050 within the sensing driving period, only until the turn-on voltage Vf of the organic light emitting diode OLED is reached for a predetermined time Δt, the source node of the driving transistor DRT is After the voltage Vs is changed, the organic light emitting diode driving period S1050 ends, and the driving transistor characteristic sensing period S1060 proceeds to perform voltage sensing.

On the other hand, as described above, the compensator 710, the voltage (Vdata2+ΔV=Vdata2+Vs) sensed by the analog-to-digital converter (ADC) during the driving transistor characteristic sensing period (S1060) is converted from a digital value, A voltage change amount (ΔV=Vs-ground voltage=Vs) of the source node N2 of the driving transistor DRT for a predetermined time Δt may be determined.

Here, the voltage change amount (ΔV=Vs) of the source node N2 of the driving transistor DRT for a predetermined time Δt corresponds to the mobility component α of the driving transistor DRT, and the driving transistor DRT can be used to calculate the mobility component (α) of

Also, as will be described later, a voltage change amount ΔV=Vs for a predetermined time Δt may be used to calculate a threshold voltage component Φ of the driving transistor DRT.

As described above, even in the sub-pixel circuit (sub-pixel structure) according to the second embodiment shown in FIG. 7 , normal sensing driving can be enabled, and when an image is displayed on the screen, that is, in real time, driving is performed. The threshold voltage and mobility of the transistor DRT may be sensed and compensated, and an afterimage compensation may also be provided.

More specifically, the compensating unit 710 performs the organic light emitting diode driving section (S1050) and the driving transistor characteristic sensing section (S1060) twice, and the driving transistor (DRT) obtained in the driving transistor characteristic sensing section (S1060). A first current value I1 and a second current value I2 are calculated based on the voltage change ΔV and the voltage change time Δt of the second node N2, respectively, and the first current value I1 and the second current value I1 Based on the current value I2, the mobility information α and the threshold voltage information Φ of the driving transistor DRT may be calculated.

As described above, while sensing the gate voltage Vg of the driving transistor DRT through the data line DL, not only the mobility information α of the driving transistor DRT but also the threshold voltage information Φ are sensed. can compensate you.

A method of calculating the mobility information α and the threshold voltage information Φ of the driving transistor DRT using the sensing result obtained in the driving transistor characteristic sensing section S1060 performed twice will be described in more detail below.

In the organic light emitting display device 100 according to the second exemplary embodiment, the voltage of the gate node of the driving transistor DRT coupled by the source voltage Vs of the driving transistor DRT changed through constant current sensing. A change can be detected and the current flowing through the driving transistor DRT can be predicted through calculation.

By performing the driving transistor characteristic sensing section S1060 twice, that is, using the voltage results sensed two times of constant current, the compensation values for alpha (α) and pi (Φ), which are characteristic values for the driving transistor DRT, are It can be predicted by calculation.

First, the current I(OLED) flowing through the organic light emitting diode OLED may be expressed as Equation 2 below.

In Equation 2, I(OLED) is a current flowing through the organic light emitting diode (OLED), and C2 is a capacitance component formed between the first electrode (eg, anode electrode) of the organic light emitting diode (OLED) and the ground node. It can be a known value.

In Equation 2, ΔV is the voltage increase during the organic light emitting diode driving period S1050 from the data voltage Vdata2 applied to the gate node N1 of the driving transistor DRT in the charging period S1040, so that the driving transistor characteristics It corresponds to the amount of voltage change of the gate node N1 of the driving transistor DRT before voltage sensing is performed in the sensing period S1060 . Δt is a time at which the voltage change amount ΔV of the gate node N1 of the driving transistor DRT occurs.

The driving transistor characteristic sensing period S1060 is performed twice to sense the voltage of the data line DL.

The gate node of the driving transistor DRT by subtracting the known data voltage Vdata from the voltage (Vsen1=Vdata+ΔV1) of the data line DL first sensed through the first driving transistor characteristic sensing period S1060 The voltage change amount ΔV1 of (N1) can be found.

By substituting the calculated ΔV1 and the predetermined Δt into Equation 2, I(OLED), which is the current flowing through the organic light emitting diode (OLED), can be calculated as I1 (=C2*ΔV1/Δt).

The gate node of the driving transistor DRT by subtracting the known data voltage Vdata from the voltage (Vsen2=Vdata+ΔV2) of the data line DL sensed secondary through the second driving transistor characteristic sensing period S1060 The voltage change amount ΔV2 of (N1) can be found.

By substituting the determined ΔV2 and the predetermined Δt into Equation 2 above, I(OLED), which is the current flowing through the organic light emitting diode (OLED), can be calculated as I2 (=C2*ΔV2/Δt).

In other words, two voltage variations (ΔV1, ΔV2) are calculated from the two sensing results (Vsen1, Vsen2) through two steps of the driving transistor characteristic sensing section S1060, and the two voltage variations (ΔV1, ΔV2) Two types of I(OLED), I1 (=C2*ΔV1/Δt) and I2 (=C2*ΔV2/Δt) can be calculated from

Meanwhile, the current I(DRT) flowing through the driving transistor DRT may be expressed as in Equation 3 below.

In Equation 3, α corresponds to the mobility component of the driving transistor DRT, and Φ corresponds to the threshold voltage component of the driving transistor DRT. Vdata-Vs may correspond to a compensation data voltage (Vdata2 in FIG. 12 ) that compensates for characteristics of the organic light emitting diode (OLED).

As in the graph shown in FIG. 5 , the current I (OLED) flowing through the organic light emitting diode (OLED) is the same as the current I (DRT) flowing through the driving transistor (DRT).

By using this relationship, the characteristic values α and Φ of the driving transistor DRT can be calculated.

For example, when the data voltage used in the primary sensing is 10V and the data voltage used in the secondary sensing is 8V, the following equation 4 has two unknowns (α, Φ). It can be expressed as an equation.

By solving these simultaneous equations, two unknowns (α, Φ) can be obtained.

As described above, the display driving sections ( S910 , S920 , S930 ) proceed, the sensing driving sections ( S1020 , S1030 , S1040 , S1050 , and S1060 ) proceed, followed by the display driving sections ( S910 , S920 , S930 ). can proceed.

Between the first section S930 in which the organic light emitting diode (OLED) emits light and the second section S930 in which the organic light emitting diode (OLED) emits light, the driving transistor DRT in the non-emission state of the organic light emitting diode (OLED) ), there may be a section S1050 in which the voltages of the first node N1 and the second node N2 rise.

According to the above description, it can be seen that the driving for sensing the characteristic value of the driving transistor DRT is performed while the image is displayed.

15 is a diagram illustrating a source driver integrated circuit SDIC of the organic light emitting display device 100 according to the second exemplary embodiment.

Referring to FIG. 15 , the source driver integrated circuit SDIC of the organic light emitting diode display 100 according to the second embodiment includes a data voltage output unit that outputs a data voltage Vdata to a first switch node Na. VOUT), the analog-to-digital converter (ADC) electrically connected to the second switch node (Nb), and one of the first switch node (Na) and the second switching node (Nb) is electrically connected to the data line (DL) It may include a switch circuit 700 and the like.

When the first switch node Na and the data line DL are connected by the switch circuit 700 , the data voltage output unit VOUT is transferred to the data line DL through the first switch node Na to the data voltage ( Vdata) can be supplied.

When the second switch node Nb and the data line DL are connected by the switch circuit 700 , the analog-to-digital converter ADC converts the voltage of the data line DL to a digital value through the second switch node Nb. to output the converted digital value.

Meanwhile, the data voltage output unit VOUT may be a digital-to-analog converter (DAC) or an output buffer for outputting an analog voltage output from the digital-to-analog converter (DAC).

When the above-described source driver integrated circuit SDIC is used, the data line DL drives the data line DL to serve as a data voltage transfer path at a certain point in time, and at another point in time, the data line DL receives a voltage. It can be controlled to act as a sensing path.

Meanwhile, the data voltage output unit VOUT may be a digital-to-analog converter (DAC) or an output buffer for outputting an analog voltage output from the digital-to-analog converter (DAC).

16 is a flowchart illustrating a method of operating the data driver 120 of the organic light emitting diode display 100 according to the second exemplary embodiment.

Referring to FIG. 16 , in an operation method of a source driver integrated circuit (SDIC) implementing a data driver 120 including a digital-to-analog converter and an analog-to-digital converter (ADC), image data is converted to a data voltage corresponding to an analog voltage. A step (S1610) of electrically connecting the converting digital-to-analog converter (DAC) to the data line (DL) to output a data voltage to the data line (DL) (S1610), and electrically connecting the analog-to-digital converter (ADC) to the data line (DL) and converting the voltage of the data line DL into a digital value and outputting the converted digital value ( S1620 ).

Using the above-described operating method of the source driver integrated circuit SDIC, the data line DL drives the data line DL to serve as a data voltage transfer path at one point in time, and at another point in time, the data line DL ) can be controlled to act as a voltage sensing path.

17 is a flowchart of a driving method of the organic light emitting display device 100 according to the second exemplary embodiment.

Referring to FIG. 17 , the organic light emitting diode display 100 according to the second exemplary embodiment includes an organic light emitting diode (OLED), a driving transistor (DRT) for driving the organic light emitting diode (OLED), and a driving transistor (DRT). ), an organic light emitting display panel 110 in which a plurality of subpixels SP including a switching transistor (a first transistor T1 ) electrically connected between the gate node of the DL and the data line DL are arranged; It may include a data driver 120 for driving (DL).

The driving method of the organic light emitting display device 100 according to the second embodiment includes a first step S1710 of outputting a first data voltage 1st Vdata to a data line DL, and a driving transistor DRT. A second step (S1720) of increasing the voltage of the gate node (N1) for a predetermined first time period (S1720), and the first sensing of the increased voltage of the gate node (N1) of the driving transistor (DRT) through the data line (DL) A third step (S1730), a fourth step (S1740) of outputting a second data voltage (2nd Vdata) to the data line (DL), and the voltage of the gate node (N1) of the driving transistor (DRT) for a second time A fifth step (S1750) of increasing the voltage during the second step (S1750), a sixth step (S1760) of secondary sensing the increased voltage of the gate node N1 of the driving transistor DRT through the data line (DL), and a third step A seventh step (S1770) of calculating threshold voltage information and mobility information of the driving transistor DRT based on the primary sensed voltage, the voltage secondarily sensed in the first time and the sixth step, and the third time (S1770), etc. may include

The above-described driving method is a driving method related to a method of predicting compensation values for alpha (α) and pi (Φ), which are characteristic values of the driving transistor DRT, through calculation using Equations 2 and 3 .

Steps S1710 and S1740 may correspond to step S1040.

Steps S1720 and S1750 may correspond to step S1050.

Steps S1730 and S1760 may correspond to step S1060.

In step S1770, the driving transistor characteristic sensing section S1060 is performed twice, that is, by using the result of the two constant current sensed voltages, the characteristic values of the driving transistor DRT are alpha (α) and pi (Φ). It is a step of predicting the compensation value through calculation.

As described above, it is possible not only to sense the mobility of the driving transistor DRT, but also without the process of saturating the voltage of the second node N2 of the driving transistor DRT. The threshold voltage can be obtained through an arithmetic process. Accordingly, the characteristic value sensing of the driving transistor DRT may be performed in real time while the image is displayed.

According to the present embodiments as described above, it is possible to provide a sub-pixel structure that enables sensing driving while deleting an existing sensing line.

According to the present embodiments, it is possible to simplify the panel design structure and the panel manufacturing process.

According to the present exemplary embodiments, characteristics of circuit elements (organic light emitting diodes and driving transistors) of each sub-pixel may be sensed and compensated in real time while an image is displayed on the screen.

According to the present embodiments, the voltage change of the gate node of the driving transistor coupled to the sensing point changed through constant current sensing is detected, rather than the sensing point for sensing the characteristic of the circuit element of each sub-pixel. A characteristic value of a circuit element can be sensed by estimating the current flowing through the driving transistor.

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: timing controller

Claims (14)

an organic light emitting display panel in which a plurality of sub-pixels defined by a plurality of data lines and a plurality of gate lines are arranged;
a data driver driving the plurality of data lines; and
a gate driver driving the plurality of gate lines;
Each of the plurality of sub-pixels,
An organic light emitting diode, a driving transistor for driving the organic light emitting diode, a first transistor controlled by a first scan signal and electrically connected between a first node of the driving transistor and a data line, and a second scan signal Controlled by, a second transistor electrically connected between the second node of the driving transistor and a ground node, and a first capacitor electrically connected between the first node and the second node of the driving transistor,
A switch circuit electrically connecting one of a first switch node to which a data voltage is input and a second switch node connected to an analog-to-digital converter to the data line;
When the first switch node and the data line are connected by the switch circuit, the data voltage input to the first switch node is supplied to the data line;
When the second switch node and the data line are connected by the switch circuit, the analog-to-digital converter senses the voltage of the data line. According to claim 1,
An organic light emitting display device in which a display driving section and a sensing driving section are alternately performed during image display. 3. The method of claim 2,
The display driving section includes a preparation section, a data input section, and an organic light emitting diode light emitting section,
During the preparation period,
The first scan signal and the second scan signal are turn-off level voltages,
During the data input period,
the switch circuit connects the data line and the first switch node,
The first scan signal and the second scan signal are changed to a turn-on level voltage,
During the organic light emitting diode light emitting period,
The first scan signal and the second scan signal are changed to a turn-off level voltage,
Then, when a predetermined time elapses, the organic light emitting diode emits light. 4. The method of claim 3,
The sensing driving section that proceeds after the organic light emitting diode light emitting section of the display driving section,
Including an organic light emitting diode characteristic sensing section, a discharging section, a charging section, an organic light emitting diode driving section and a driving transistor characteristic sensing section,
After the driving transistor characteristic sensing period, the preparation period of the display driving period proceeds,
During the organic light emitting diode characteristic sensing period,
The first scan signal is a turn-on level voltage, the second scan signal is a turn-off level voltage, the switch circuit connects the second switch node and the data line, and the analog-to-digital converter provides the data Senses the line voltage,
During the discharge period,
The first scan signal is a turn-off level voltage, the second scan signal is a turn-on level voltage,
During the charging period,
The first switch node and the data line are connected by the switch circuit, the first scan signal is a turn-on level voltage, the second scan signal is a turn-on level voltage,
During the organic light emitting diode driving period,
The first scan signal is a turn-off level voltage, the second scan signal is a turn-off level voltage,
During the driving transistor characteristic sensing period,
The first scan signal is a turn-on level voltage, the second scan signal is a turn-off level voltage, the switch circuit connects the second switch node and the data line, and the analog-to-digital converter provides the data An organic light emitting display device that senses a line voltage. 5. The method of claim 4,
In the organic light emitting diode characteristic sensing period, the voltage of the data line is
An organic light emitting diode display having a higher voltage than the voltage of the data line in the data input period of the display driving period. 5. The method of claim 4,
and a compensator configured to calculate a voltage change amount of the first node of the driving transistor from the voltage sensed by the analog-to-digital converter in the organic light emitting diode characteristic sensing period. 5. The method of claim 4,
During the driving transistor characteristic sensing period, the voltage of the data line is
An organic light emitting diode display that is higher than a voltage of the data line during the charging period. 5. The method of claim 4,
and a compensator configured to calculate a voltage change of the second node of the driving transistor from the voltage sensed by the analog-to-digital converter during the characteristic sensing period of the driving transistor. 9. The method of claim 8,
The compensation unit,
Calculate a first current value and a second current value from the voltage change and voltage change time of the second node of the driving transistor obtained in the driving transistor characteristic sensing period performed twice,
An organic light emitting display device for calculating mobility information and threshold voltage information of the driving transistor based on the first current value and the second current value. An organic light emitting display panel in which a plurality of sub-pixels defined by a plurality of data lines and a plurality of gate lines are arranged, the organic light emitting display panel comprising:
Each of the plurality of sub-pixels,
an organic light emitting diode,
a driving transistor for driving the organic light emitting diode;
a first transistor controlled by a first scan signal and electrically connected between a first node of the driving transistor and a data line;
a second transistor controlled by a second scan signal and electrically connected between a second node of the driving transistor and a ground node;
and a first capacitor electrically connected between a first node and a second node of the driving transistor. 11. The method of claim 10,
Between a first section in which the organic light emitting diode emits light and a second section in which the organic light emitting diode emits light,
An organic light emitting display panel having a section in which voltages of the first node and the second node of the driving transistor increase in the non-emission state of the organic light emitting diode. delete delete delete

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