KR102416750B1 - Organic light emitting display device and the method for driving the same - Google Patents

Abstract

The organic light emitting display device of the present invention includes a sensing unit for acquiring a plurality of sensing values in a sensing driving for sensing a degree of deterioration of an organic light emitting diode, and determining whether the plurality of sensing values are included within a preset sensing voltage range. By including a determination unit and a final sensed value determination unit that selects any one of a plurality of sensed values as a final sensed value according to the result of the determination unit, the sensed value overflows or underflows the sensing voltage range It has the effect of preventing compensation errors and screen quality degradation caused by having
In addition, the method for driving an organic light emitting display device of the present invention obtains a plurality of sensing values in a sensing section and selects and compensates for all sensing values included in a preset sensing voltage range, thereby preventing compensation errors and screen quality degradation. It works.

Description

Organic light emitting display device and driving method thereof

The present invention relates to an organic light emitting display device and a driving method thereof.

Recently, an organic light emitting display device, which has been in the spotlight as a display device, has advantages such as fast response speed, 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 brightness of sub-pixels selected by a scan signal is controlled according to a gray level of data.

Each sub-pixel disposed on the display panel of the organic light emitting diode display basically includes a driving transistor for driving an organic light emitting diode, a switching transistor for transferring a data voltage to a gate node of the driving transistor, and maintaining a constant voltage for one frame time. It may be configured to include a storage capacitor, etc., which serves to serve.

The driving transistor in each sub-pixel may be deteriorated as the driving time increases, and thus characteristic values such as threshold voltage and mobility may change. Also, since the degree of deterioration may be different for each driving transistor, a characteristic value deviation between driving transistors in each subpixel may occur.

The organic light emitting diodes in each sub-pixel also deteriorate as the driving time increases, so characteristic values such as threshold voltage may change and the degree of deterioration between the organic light emitting diodes may be different. Deviations may occur.

As described above, the deviation of the characteristic value between the sub-pixels caused by the deviation of the characteristic value between the driving transistors and the deviation of the characteristic value between the organic light emitting diodes causes the luminance deviation between the sub-pixels to cause a screen abnormality such as a screen afterimage or the luminance of the display panel. may cause unevenness.

Accordingly, a technology for compensating for a characteristic value deviation between sub-pixels has been developed. In the compensation method, first, the organic light emitting diode display is sensed and driven to sense the characteristic value of the driving transistor or the organic light emitting diode of the subpixel, and then the sensed value Vsen is obtained, and data to be applied to the subpixel based on the sensed value Vsen. This is done in a way that compensates for

In particular, the voltage range of the sensing value Vsen obtained by sensing the characteristic value of the sub-pixel is fixed to a certain range due to a limitation of a source driver integrated circuit (SDIC).

However, when the sensed value obtained by sensing is not within the sensing voltage range to compensate the characteristic value between the driving transistors and the characteristic value due to deterioration of the organic light emitting diode, a compensation error occurs such as data compensation with an incorrect value.

Such a compensation error causes an abnormality in the screen, such as a screen afterimage remaining on the display panel, and deteriorates image quality.

The present invention obtains a plurality of sensing values and selects and compensates a sensing value within a sensing voltage range among the obtained sensing values, so that the sensing value overflows or has a value below the sensing voltage range. An object of the present invention is to provide an organic light emitting display device that prevents a compensation error and screen quality degradation and a driving method thereof.

An organic light emitting display device of the present invention for solving the problems of the prior art as described above includes an organic light emitting diode, a display panel including a plurality of sub-pixels each having a driving transistor for driving the organic light emitting diode, and the display panel. A plurality of sensing driving units including a gate driver supplying a scan signal, a data driver supplying a data voltage to the display panel, and a timing controller controlling the gate driver and the data driver, for sensing the degree of deterioration of the organic light emitting diode. A sensing unit obtaining a sensed value, a determining unit determining whether the plurality of sensing values are within a preset sensing voltage range, and selecting any one of a plurality of sensing values as a final sensing value according to a result of the determining unit By including a final sensed value determining unit that has the effect of preventing compensation errors and screen quality deterioration caused by the sensed value exceeding the sensing voltage range or having a value below the sensing voltage range

In addition, the method for driving an organic light emitting display device of the present invention includes a display panel including an organic light emitting diode, a plurality of sub-pixels each having a driving transistor for controlling the organic light emitting diode, and a gate for supplying a scan signal to the display panel A method of driving an organic light emitting display device comprising: a driving unit; a data driving unit supplying a data voltage to the display panel; and a timing controller controlling the gate driving unit and the data driving unit. The driving includes: acquiring a plurality of sensing values in a sensing section; comparing and determining whether the acquired sensing values are included in a preset sensing voltage range; when all of the sensing values are included in a preset sensing voltage range; or By including the step of selecting a final sensed value according to the case that only one is included, and performing data compensation based on the selected final sensed value, the sensed value overflows or underflows the sensed voltage range It has the effect of preventing compensation errors and screen quality deterioration caused by having it.

An organic light emitting display device and a driving method thereof according to the present invention obtain a plurality of sensed values and select and compensate a sensed value within a sensed voltage range from among the obtained sensed values, so that the sensed value overflows the sensed voltage range. ) or has an underflow value, which has the effect of preventing compensation errors and screen quality degradation.

1 is a schematic system configuration diagram of an organic light emitting display device according to the present invention.
2 is an exemplary diagram of a sub-pixel structure of an organic light emitting diode display according to the present invention.
3 is a diagram illustrating distributions of sensing values of an organic light emitting diode display.
4 is a diagram for explaining a principle of acquiring a normal sensing value according to a sensing driving of an organic light emitting diode display according to the present invention.
5 is a block diagram illustrating a sensing and compensation system according to the present invention.
6 is a diagram illustrating control signals and voltage waveforms for each section in sensing driving of the organic light emitting display device according to the present invention.
7A to 7C are diagrams illustrating sensing driving of the organic light emitting diode display according to the present invention.
8 is a diagram illustrating a state in which a plurality of sensing values are acquired in sensing driving of the organic light emitting diode display according to the present invention.
9 is a diagram illustrating a specific embodiment of FIG. 8 .
10 and 11 are diagrams showing changes in voltage and current according to the degree of deterioration of the organic light emitting diode.
12 is a flowchart illustrating sensing driving of an organic light emitting diode display according to the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative and the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, cases including the plural are included unless otherwise explicitly stated.

In interpreting the components, it is construed as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, when the temporal relationship is described as 'after', 'following', 'after', 'before', etc., 'immediately' or 'directly' Unless ' is used, cases that are not continuous may be included.

Although the first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

Each feature of the various embodiments of the present invention can be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other or implemented together in a related relationship. may be

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. And in the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals refer to like elements throughout.

1 is a schematic system configuration diagram of an organic light emitting display device according to the present invention.

Referring to FIG. 1 , the organic light emitting diode display 100 according to the present invention includes a plurality of data lines (DL1 to DLm, m is a natural number greater than or equal to 2) and a plurality of gate lines (GL1 to GLn, n is a natural number greater than or equal to 2). is disposed, the display panel 110 in which a plurality of sub-pixels are arranged in a matrix type, the data driver 120 for driving the plurality of data lines DL1 to DLm, and the plurality of gate lines GL1 to GLn It includes a gate driver 130 for driving, a data driver 120 , and a timing controller 140 for controlling the gate driver 130 .

The data driver 120 drives the plurality of data lines DL1 to DLm by supplying data voltages to the plurality of data lines DL1 to DLm. Here, the data driver 120 is also referred to as a source driver.

The gate driver 130 sequentially drives the plurality of gate lines GL1 to GLn by sequentially supplying scan signals to the plurality of gate lines GL1 to GLn. Here, the gate driver 130 is also referred to as a scan driver.

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

The timing controller 140 starts scanning according to the timing implemented in each frame, converts 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 and control the data operation at an appropriate time according to the scan.

The gate driver 130 sequentially drives the plurality of gate lines by sequentially supplying a scan signal of an on voltage or an off voltage to the plurality of gate lines under the control of the timing controller 140 . .

The gate driver 130 may be positioned on only one side of the display panel 110 as shown in FIG. 1 or, in some cases, on both sides, according to a driving method.

Also, the gate driver 130 may include one or more gate driver integrated circuits (GDICs).

Each of the one or more gate driver integrated circuits included in the gate driver 130 may include a shift register, a level shifter, and the like.

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

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

Each source driver integrated circuit included in the data driver 120 may include a logic unit including a shift register and a latch circuit, a digital analog converter (DAC), an output buffer, and the like. Accordingly, a sensing unit (eg, an analog It may further include an analog digital converter (ADC).

Meanwhile, the timing controller 140 includes a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input data enable (DE: Data Enable) signal, a clock signal (CLK), etc. together with the input image data. It receives various timing signals from the outside (eg, host system).

The timing controller 140 converts 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, as well as the data driver 120 and the gate driver 130 . ), the data driver 120 and the gate driver 130 receive timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input DE signal, and a clock signal to generate various control signals. ) is output.

For example, the timing controller 140 controls the gate driver 130 , a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE). : Outputs various gate control signals (GCS: Gate Control Signal) including Gate Output Enable).

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 timing 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 .

Referring to FIG. 1 , the timing controller 140 includes a source printed circuit board to which a source driver integrated circuit is bonded and a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit (FPC). It may be disposed on a control printed circuit board connected through the

A power controller (not shown) that supplies various voltages or currents to the display panel 110 , the data driver 120 , and the gate driver 130 or controls various voltages or currents to be supplied is further disposed on the control printed circuit board can be Such a power controller is also referred to as a power management integrated circuit (PMIC).

Each of the plurality of sub-pixels disposed on the display panel 110 according to the present invention may be composed of, for example, circuit elements such as an organic light emitting diode (OLED), two or more transistors, and at least one capacitor. have.

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

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

Referring to FIG. 2 , each subpixel SP disposed on the display panel 110 according to the present invention includes an organic light emitting diode (OLED), a driving transistor (DRT), and a switching transistor (SWT). , a sensing transistor (SENT), a storage capacitor (Cst), and the like.

As shown in FIG. 2 , a subpixel structure including three transistors DRT, SWT, and SENT and one capacitor Cst is referred to as a 3T (Transistor) 1C (Capacitor) structure.

Referring to FIG. 2 , an organic light emitting diode (OLED) may include, for example, a first electrode (eg, an anode or cathode electrode), an organic layer, and a second electrode (eg, a cathode electrode or an anode electrode).

For example, the first electrode of the organic light emitting diode (OLED) is connected to an N2 node (eg, a source node or a drain node) of the driving transistor (DRT), and the second electrode of the organic light emitting diode (OLED) is connected to the ground voltage (EVSS). ) can be approved.

Referring to FIG. 2 , the driving transistor DRT is a transistor that supplies a driving current to the organic light emitting diode OLED to drive the organic light emitting diode OLED, and a driving voltage line that supplies a driving voltage EVDD. DVL) and the first electrode of the organic light emitting diode (OLED) may be electrically connected.

The driving transistor DRT, for example, includes an N1 node (first node) corresponding to a gate node, an N2 node (second node) corresponding to a source node or a drain node, and a drain node or a source node. It has an N3 node (the third node).

Referring to FIG. 2 , the switching transistor SWT is a transistor for transferring the data voltage Vdata to the N1 node of the driving transistor DRT, and supplies the N1 node and the data voltage Vdata of the driving transistor DRT. are electrically connected between the data lines DL.

The switching transistor SWT may be turned on by the scan signal SCAN applied to the gate node to transmit the data voltage Vdata to the N1 node corresponding to the gate node of the driving transistor DRT.

Referring to FIG. 2 , the storage capacitor Cst is a capacitor that maintains a constant voltage for one frame time, and is electrically connected between the N1 node and the N2 node of the driving transistor DRT.

Referring to FIG. 2 , the sensing transistor SENT applies an initialization voltage Vpre to the N2 node of the driving transistor DRT or is involved in voltage sensing of the N2 node of the driving transistor DRT, and is driven. It is electrically connected between the N2 node of the transistor DRT and a reference voltage line (RVL) supplying the initialization voltage Vpre.

The sensing transistor SENT is turned on by a sense signal SENSE, which is a type of scan signal applied to the gate node, and applies the initialization voltage Vpre supplied through the reference voltage line RVL to the driving transistor DRT. It can be granted to the N2 node of

Meanwhile, referring to FIG. 2 , the gate node of the switching transistor SWT and the gate node of the sensing transistor SENT may be electrically connected to the same gate line. In other words, the gate signals SCAN and SENSE may be commonly applied to the gate node of the switching transistor SWT and the gate node of the sensing transistor SENT through one and the same gate line. In this case, the scan signal SCAN and the sense signal SENSE are the same gate signal.

Alternatively, the gate node of the switching transistor SWT and the gate node of the sensing transistor SENT may be electrically connected to different gate lines. In this case, each of the scan signal SCAN and the sense signal SENSE may be separately applied to the gate node of the switching transistor SWT and the gate node of the sensing transistor SENT through different gate lines.

Meanwhile, as shown in FIG. 2 , the reference voltage line RVL operates the first switch SW1 according to the switch control signal SPRE to receive the initialization voltage.

A line capacitor Cline may be formed on the reference voltage line RVL.

Meanwhile, each driving transistor DRT has characteristic values such as a threshold voltage (Vth) and mobility. Also, the characteristic value of the driving transistor DRT may be changed as deterioration proceeds according to the driving time.

For this reason, a difference in the degree of deterioration may exist between the driving transistors DRT in each sub-pixel, and a deviation in characteristic values between the driving transistors DRT in each sub-pixel may exist.

A characteristic value deviation between the driving transistors DRT in each sub-pixel may cause a luminance deviation between the respective sub-pixels, which may be a major factor causing image quality deterioration.

In addition to the characteristic deviation (eg, threshold voltage deviation, mobility deviation) between the driving transistors (DRT), the characteristic value deviation ( Example: threshold voltage deviation, etc.) may also exist.

The above-described deviation in characteristic values between the driving transistors DRT and deviation in the characteristic values between the organic light emitting diodes (OLED) corresponds to the deviation in the characteristic values of sub-pixels, and is a factor that causes luminance deviation between sub-pixels and inhibits luminance uniformity. becomes this

Accordingly, in order to improve the image quality, compensation for the sub-pixel characteristic value deviation is required.

Accordingly, each sub-pixel in the display panel 110 according to the present invention has a sub-pixel structure capable of being sensed, as shown in FIG. 2 .

In addition, as shown in FIG. 2 , the organic light emitting display device 100 according to the present invention is a sensing configuration for sensing a characteristic value or a characteristic value deviation of each sub-pixel, and the second switch SW2 is configured to transmit a sampling control signal ( SAM) and may further include an analog-to-digital converter (ADC) electrically connected to the reference voltage line RVL.

The analog-to-digital converter (ADC) senses the voltage of the reference voltage line (RVL), converts the sensed sensed value (Vsen: sensed voltage value) to a digital value, generates sensed data, and converts the generated sensed data to a digital value. may be transmitted to the timing controller 140 .

Sensing the voltage of the reference voltage line RVL by the analog-to-digital converter ADC has the same effect as sensing the voltage of the N2 node of the driving transistor DRT when the sensing transistor SENT is turned on.

Here, the voltage of the N2 node of the driving transistor DRT reflects the characteristic values (eg, threshold voltage, mobility) of the driving transistor DRT and the characteristic values (eg, threshold voltage) of the organic light emitting diode (OLED). It can be voltage. In the present invention, the organic light emitting diode (OLED) deterioration sensing driving for compensating for a case in which a characteristic value is changed due to deterioration of the organic light emitting diode (OLED) will be mainly described.

3 is a diagram illustrating distributions of sensing values of an organic light emitting diode display.

Referring to FIG. 3 , in general, a sensing voltage range capable of sensing a characteristic value of a subpixel of an organic light emitting display device is fixed to a certain range due to a voltage range limitation of the source driver integrated circuit SDIC. Therefore, when the sensing value (Vsen) obtained through sensing driving is located within the sensing voltage range, accurate compensation is performed, but when it exceeds the sensing voltage range, a compensation error occurs in which data compensation is performed with an incorrect compensation value. .

As shown in FIG. 3 , a case in which the distribution of the sensing value Vsen exceeds the upper and lower limits of the sensing voltage range is referred to as an overflow and an underflow, respectively. Therefore, when a part of the distribution region of the sensing value Vsen exceeds the upper limit of the sensing voltage range, since the sensing value Vsen in the excess range exceeds the sensing voltage range, an accurate compensation value corresponding to the sensing value Vsen is obtained. This cannot be done, resulting in a compensation error.

In addition, when a part of the distribution region of the sensing value Vsen exists below the lower limit of the sensing voltage range, the sensing value Vsen below the lower limit also cannot obtain an accurate compensation value, resulting in a compensation error. As such, when a compensation error occurs due to overflow or underflow of the sensing value Vsen, accurate compensation data for deterioration of the organic light emitting diode cannot be obtained, and thus screen quality is deteriorated.

4 is a diagram for explaining a principle of acquiring a normal sensing value according to a sensing driving of an organic light emitting diode display according to the present invention.

Referring to FIG. 4 , driving of the organic light emitting diode display includes driving for displaying an image and sensing driving for sensing characteristic values of sub-pixels. As shown in the figure, the sensing value (Vsen: sensing voltage) obtained according to the sensing driving has linearity that increases in proportion to the time T in the sensing section.

The organic light emitting display device of the present invention sequentially acquires the sensing value Vsen two or more times in a sensing section, and takes a sensing value Vsen included in the sensing voltage range among the acquired sensing values Vsen, The compensation error due to overflow or underflow of the sensing value (Vsen) was improved and the screen quality was improved.

That is, as shown in FIG. 4 , a first sensing value Vsen1 and a second sensing value Vsen2 are obtained at time points t1 and t2 in the sensing section, and the obtained first and second sensing values Vsen1, Among Vsen2), a second sensing value Vsen2 existing within the sensing voltage range was selected, and data compensation was performed to prevent image quality deterioration due to overflow or underflow of the sensing value.

5 is a block diagram illustrating a sensing and compensation system according to the present invention.

Referring to FIG. 5 together with FIG. 1 , the organic light emitting diode display 100 of the present invention includes a sensing and compensation system 500 . The sensing and compensation system 100 may be disposed inside or outside the typing controller 140 . The sensing and compensation system 500 includes a sensing unit 501 that acquires a plurality of sensing values Vsen in a sensing step for sensing a degree of deterioration of an organic light emitting diode (OLED), and a sensing unit 501 A determination unit 502 that determines whether the plurality of sensing values Vsen is included within a preset sensing voltage range, and a final selection of any one of the plurality of sensing values Vsen according to the result of the determination unit 502 It includes a sensed value determiner 503 and a compensator 504 that performs data compensation based on the final sensed value determined by the final sensed value determiner 503 . Accordingly, the ADC described with reference to FIG. 2 may be disposed between the final sensed value determiner 503 and the compensator 504 .

More specifically, when sensing driving is performed on the organic light emitting display device 100 of the present invention, the sensing unit 501 sequentially applies a plurality of sampling control signals SAM in a sensing section to obtain a plurality of sensing values. (Vsen) is sensed. Accordingly, in the present invention, sampling for obtaining the sensed value Vsen in the sensing section may be performed together.

When the sensing unit 501 acquires a plurality of sensing values Vsen, the determining unit 502 determines whether voltages corresponding to the sensing values Vsen are included in a preset sensing voltage range.

For example, when two first sensing values Vsen1 and second sensing values Vsen2 are obtained, the determination unit 502 sets the first sensing value Vsen1 and the second sensing value Vsen2 in advance. It is compared and judged whether it is included in the sensing voltage range.

Then, the final sensing value determining unit 503 finally selects any one of the first sensing value Vsen1 and the second sensing value Vsen2 based on the information of the determining unit 502 . In this case, when only one of the first and second sensed values Vsen1 and Vsen2 is included in the sensing voltage range, the included sensed value is selected, and all of the first and second sensed values Vsen1 and Vsen2 are sensed. When it is included in the voltage range, a value having a larger sensed value (sensing voltage) is selected from among the first and second sensed values Vsen1 and Vsen2.

As such, when a sensed value is selected by the final sensed value determiner 503 , it is provided to the compensator 504 , and then data compensation is performed based on the selected final sensed value.

As described above, in the present invention, by acquiring two or more sensing values in the sensing step for sensing the degree of deterioration of the organic light emitting diode, the sensed value exceeds or exceeds the sensing voltage range. Occurs when obtained It has the effect of preventing possible compensation errors and screen quality degradation.

6 is a view showing control signals and voltage waveforms for each section in sensing driving of the organic light emitting display device according to the present invention, and FIGS. 7A to 7C are views showing sensing driving of the organic light emitting display device according to the present invention. to be.

6 to 7C , in the organic light emitting diode (OLED) deterioration sensing driving of the organic light emitting diode display 100 according to the present invention, an initialization period (Tint) in which an initialization step is performed, and a tracking period (Ttrac) in which the boosting step is performed ), and a sensing and sampling section (Tsen&Tsam) in which the sensing step and the sampling step are performed together.

In the initialization period Tint, the scan signal SCAN, the sense signal SENSE, and the switch control signal SPRE are applied at an on level, and the sampling control signal SAM is applied at an off level. As a result, as shown in FIG. 7A , the sensing data voltage Vdata_SEN is applied to the N1 node N1 of the driving transistor DRT, and the initialization voltage Vpre is applied to the N2 node N2 of the driving transistor DRT. It is applied through (RVL) and the sensing transistor (SENT).

In the tracking period Ttrac, only the switch control signal SPRE is applied at an on level, and the scan signal SCAN, the sense signal SENSE, and the sampling control signal SAM are applied at an off level.

As a result, as shown in FIG. 7B , the N1 node N1 and the N2 node N2 of the driving transistor DRT float, and the current between the N3 node N3 and the N2 node (drain-source node) of the driving transistor DRT (Ids) is applied to the organic light emitting diode (OLED). The potential of the N2 node N2 (source node) is boosted by the drain-source node current Ids of the driving transistor DRT, and the N1 node N1 electrically coupled to the source node N2 is also boosted. is boosted When the potential of the source node N2 is higher than the operating point voltage of the organic light emitting diode OLED, the organic light emitting diode OLED is turned on.

When the organic light emitting diode (OLED) is turned on, the potential of the N2 node N2 varies according to the degree of degradation, and the potential of the N1 node N1 also varies according to the degree of degradation.

Meanwhile, in the tracking section Ttrac, the scan signal SCAN may be applied to the off level simultaneously with the sense signal SENSE, but as shown in FIG. 6 , the scan signal SCAN is delayed than the sense signal SENSE. It may be applied at an off level.

In this way, there is an effect that the degree of deterioration of the organic light emitting diode (OLED) is reflected to some extent in advance in the N2 node (source node) at the initial point of the boosting step.

In the sensing and sampling period Tsen&Tsam, the sense signal SENSE is applied to an on level, and the switch control signal SPRE maintains an on level for a predetermined period and then is inverted to an off level. Then, the scan signal SCAN is applied at an off level.

In particular, in the sensing driving of the organic light emitting display device of the present invention, the sampling control signal SAM maintains the off level in the sensing and sampling period Tsen&Tsam, and then the on level is sequentially applied twice, so that the first sensing value Vsen1 is and the second sensing value Vsen2.

Referring to FIG. 7C , the voltage VN1N2 between the N1 node and the N2 node of the driving transistor DRT is set according to the degree of deterioration of the organic light emitting diode OLED, and the set voltage between the N1 node and the N2 node is set. The current Ids between the N3 node and the N2 node of the driving transistor DRT determined according to (VN1N2) is stored in the line capacitor Cline of the reference voltage line RVL.

Since the N2 node (source node) of the driving transistor DRT is floated after the initialization voltage Vpre is applied again, when the potential of the N2 node N2 is lowered, the N1 node is affected by the coupling of the storage capacitor Cst. The potential is also lowered. In this case, the degree to which the potential of the N1 node N1 is lowered may vary depending on the degree of deterioration of the organic light emitting diode (OLED).

In other words, the degree of deterioration of the organic light emitting diode (OLED) is expressed as a potential difference between the N1 node N1, and the voltage difference at the N1 node N1 induces a voltage difference between VN1N2 of the driving transistor DRT and depends on the degree of deterioration. The current flowing through the reference voltage line RVL is different.

This current is stored in the line capacitor Cline of the reference voltage line RVL. When the current flowing through the reference voltage line RVL decreases in proportion to deterioration, the voltage stored in the line capacitor Cline also decreases. When the charging slope of the voltage stored in the line capacitor Cline is large, the current flowing through the reference voltage line RVL is large, which means that the deterioration degree of the organic light emitting diode OLED is small.

Conversely, when the charging slope of the voltage stored in the line capacitor Cline is small, the current flowing through the reference voltage line RVL is small, which means that the degree of deterioration of the organic light emitting diode OLED is large.

Referring to FIG. 6 , it can be seen that the slope of the voltage charged in the line capacitor Cline of the reference voltage line RVL varies depending on before (solid line) and after degradation (dotted line). Expanding this, the slope of the charged voltage may vary according to the degree of deterioration of the organic light emitting diode (OLED) disposed in each sub-pixel.

In the present invention, the first sensing value Vsen1 and the second sensing value Vsen2 are sequentially sensed twice in the sensing and sampling period Tsen&Tsam, that is, the voltage charged in the line capacitor Cline of the reference voltage line RVL. ) is obtained.

The first sensed value Vsen1 may have different voltage values before and after deterioration, and the second sensed value Vsen2 may also have different voltages before and after deterioration. Accordingly, both the first and second sensed values Vsen1 and Vsen2 may be located in the sensing voltage range according to the voltage gradient charged in the line capacitor Cline, and either one is located at an overflow or underflow position. can do. Accordingly, when one sensing value is obtained through one sampling operation, a compensation error occurs if the obtained sensing value is not included in the sensing voltage range.

In the present invention, the first sensed value (Vsen1) and the second sensed value (Vsen2) are obtained using the point that the sensed value (sensing voltage) has linearity that increases with time, and then the sensing and compensation system of FIG. The final sensed value was determined according to the process described in , to prevent compensation errors and screen quality degradation that may occur when the sensed value exceeds or falls below the sensing voltage range.

8 is a diagram illustrating a state in which a plurality of sensing values are acquired in sensing driving of an organic light emitting diode display according to the present invention, and FIG. 9 is a diagram illustrating a specific embodiment of FIG. 8 , and FIGS. 10 and 11 . is a diagram showing changes in voltage and current according to the degree of deterioration of the organic light emitting diode.

First, referring to FIGS. 10 and 11 together with FIG. 7C , the organic light emitting diode OLED emits light by the voltage VN1N2 between the N1 node and the N2 node of the driving transistor DRT, and N2 of the driving transistor DRT. The voltage at the node N2 is determined according to a voltage division rule between the first resistor R1 of the driving transistor DRT and the second resistor R2 of the organic light emitting diode OLED.

When the organic light emitting diode OLED is deteriorated, the second resistance R2 is increased, and the voltage of the N2 node of the driving transistor DRT is detected according to the increased second resistance R2. In addition, as shown in FIG. 11, since the current Ids between the N3 node and the N2 node of the driving transistor DRT decreases due to deterioration, the voltage between VN1N2 becomes smaller after deterioration than before deterioration (A- >B).

Accordingly, since the magnitude of the voltage stored in the line capacitor Cline of the reference voltage line RVL is also charged to a small value according to the degree of degradation, as shown in FIG. 8 , the sensing and sampling period Tsen&Tsam according to the degree of degradation. The slope of the voltage charged in the line capacitor Cline is different. For example, the slope of the solid line is the slope of the voltage charged in the line capacitor Cline before degradation of the organic light emitting diode (OLED), and the slope of the dotted line is the slope of the line capacitor Cline after the degradation of the organic light emitting diode (OLED) is charged. As shown in the figure, the first sensed value Vsen1 has a different value depending on the degree of deterioration if the gradient of the applied voltage is the same.

Similarly, the second sensing value Vsen2 has a different value according to the degree of deterioration of the organic light emitting diode (OLED). That is, when the organic light emitting diode display drives the display, the degree of deterioration of the organic light emitting diode (OLED) disposed in each sub pixel varies due to a difference (gradation difference) in data voltages supplied to each sub pixel.

Referring to FIG. 9 , there is shown a graph in which the slopes of the voltage charged in the line capacitor Cline of the reference voltage line RVL are different according to the degree of deterioration of the organic light emitting diode (OLED) (①②③④).

It can be seen that the voltage slope of ① has the largest and sequentially decreases, and the voltage gradient of ④ is the smallest. In FIG. 9, when the sensing voltage range is 0.5 [V] to 3.5 [V], and the time of the sensing and sampling period (Tsen&Tsam) is 80 [㎲], the first sensing value at 40 [㎲] and 80 [㎲] (Vsen1) and the second sensed value (Vsen2) are sampled.

When the slope of the voltage charged in the line capacitor Cline of the reference voltage line RVL is equal to ①, only the first sensing value Vsen1 is the upper limit of the sensing voltage range of 3.5 [V], and the second sensing value Vsen2 ) is 7[V], and it can be seen that overflow occurred. Accordingly, in this case, data compensation is performed by selecting the first sensing value Vsen1 obtained by sampling at 40 [μs] as the final sensing value.

When the slope of the voltage charged in the line capacitor Cline is equal to ②, since both the first sensed value Vsen1 and the second sensed value Vsen2 are within the sensing voltage range, in this case, the first sensed value Vsen1 and Data compensation is performed by selecting a value having a high voltage among the second sensing values Vsen2 as the final sensing value. Therefore, the second sensing value Vsen2: 3.5 [V] obtained by sampling at 80 [㎲] is selected as the final sensing value.

Even in case of ③, both the first sensing value (Vsen1) obtained by sampling at 40 [㎲] and the second sensing value (Vsen2) obtained by sampling at 80 [㎲] are within the sensing voltage range, so the voltage of the sensed value is Compensation is performed by selecting a high second sensed value (Vsen2) of 80[µs] as the final sensed value.

In the case of ④, the first sensing value (Vsen1) obtained by sampling at 40 [㎲] is an underflow located below the lower limit of the sensing voltage range, and the second sensing value (Vsen2) obtained by sampling at 80 [㎲] is the lower limit of the sensing voltage range, 0.5[V]. Accordingly, data compensation is performed by selecting the second sensing value Vsen2 included in the sensing voltage range as the final sensing value.

As described above, in the present invention, a plurality of sensing values are obtained by using a point in which the voltage gradient charged in the line capacitor Cline is different according to the degree of deterioration of the organic light emitting diode, and then a sensing value included in the sensing voltage range is selected. By doing so, compensation errors and screen quality deterioration caused by the sensed value not falling within the sensing voltage range were prevented.

12 is a flowchart illustrating sensing driving of the organic light emitting diode display according to the present invention.

12 , in the sensing driving of the organic light emitting diode display according to the present invention, in the sensing step for sensing the degree of deterioration of the organic light emitting diode (OLED), sampling signals are applied twice to obtain a first sensed value (Vsen1) and a second value (Vsen1). 2 The sensed value Vsen2 is acquired (S1101). In this case, the second sampling signal can be supplied by dividing the time of the sensing and sampling section (Tsen&Tsam) of the present invention by two, and when a plurality of sensing values are obtained by applying a plurality of sampling signals, the sensing and sampling section (Tsen&Tsam) The sampling signals may be supplied by equally dividing the time of .

As above, when the first sensed value (Vsen1) and the second sensed value (Vsen2) are obtained, it is compared and determined whether the first and second sensed values (Vsen1, Vsen2) are included within a preset sensing voltage range ( S1102).

Then, any one of the first and second sensed values Vsen1 and Vsen2 is selected and determined as the final sensed value (S1103). In this case, when both the first and second sensing values Vsen1 and Vsen2 are included in the sensing voltage range, a sensing value having a large voltage is selected as the final sensing value. In addition, when only one of the first and second sensing values Vsen1 and Vsen2 is included in the sensing voltage range, the included sensing value is selected as the final sensing value.

As described above, when the final sensed value among the sensed values is determined, data compensation is performed based on this to drive the organic light emitting diode display (S1104).

As described above, the organic light emitting display device and the method for driving the same according to the present invention acquire a plurality of sensing values and select and compensate a sensing value within a sensing voltage range from among the acquired sensing values, so that the sensed value changes the sensing voltage range. It has an effect of preventing compensation errors and screen quality degradation caused by having an overflow or underflow value.

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. Accordingly, 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 scope equivalent thereto should be construed as being included in the scope of the present invention.

100: organic light emitting display device
110: display panel
120: data driving unit
130: gate driver
140: timing controller
500: sensing and compensation system

Claims (9)

a display panel including an organic light emitting diode and a plurality of sub-pixels each having a driving transistor for driving the organic light emitting diode;
a gate driver supplying a scan signal to the display panel;
a data driver supplying a data voltage to the display panel; and
a timing controller for controlling the gate driver and the data driver;
A sensing unit which acquires a plurality of sensing values in a sensing driving for sensing the degree of deterioration of the organic light emitting diode;
a determination unit for determining whether the plurality of sensing values are included within a preset sensing voltage range;
and a final sensing value determining unit that selects any one of a plurality of sensing values as a final sensing value according to the result of the determining unit,
The plurality of sensing values include a first sensing value and a second sensing value sequentially acquired over time in one sensing section of the sensing driving,
An organic light emitting diode display having different values from the first sensed value and the second sensed value. According to claim 1,
The organic light emitting display device further comprising a compensator for performing data compensation based on the final sensed value selected by the final sensed value determiner. delete According to claim 1,
The final sensing value determiner selects a sensing value included in the sensing voltage range as the final sensing value when only one of the voltages of the first sensing value and the second sensing value is included in a preset sensing voltage range. . According to claim 1,
When the voltages of the first sensed value and the second sensed value are all included in a preset sensing voltage range, the final sensed value determiner uses a sensed value with a higher voltage among the first and second sensed values as the final sensed value. Organic light emitting display of choice. A display panel including an organic light emitting diode, a plurality of sub-pixels each having a driving transistor for controlling the organic light emitting diode, a gate driver supplying a scan signal to the display panel, and data supplying a data voltage to the display panel A method of driving an organic light emitting display device comprising: a driver; and a timing controller for controlling the gate driver and the data driver;
Sensing driving for sensing the degree of deterioration of the organic light emitting diode,
acquiring a plurality of sensing values in a sensing section;
comparing and determining whether the acquired sensing values are within a preset sensing voltage range;
selecting a final sensed value according to a case in which all of the sensed values are included in a preset sensing voltage range or only one of the sensed values; and
and performing data compensation based on the selected final sensing value.
The step of acquiring a plurality of sensing values in the sensing section includes:
and acquiring a first sensed value and a second sensed value sequentially having different values over time in one sensing section. delete 7. The method of claim 6,
When any one of the first and second sensing values is included in a preset sensing voltage range, the organic light emitting display driving method of selecting the included sensing value as a final sensing value. 7. The method of claim 6,
When the first and second sensing values are both included in a preset sensing voltage range, a sensing value having a higher voltage among the first and second sensing values is selected as a final sensing value.

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