KR102368078B1 - Organic light emitting display device and method for driving the same - Google Patents

Abstract

The present invention discloses an organic light emitting display device and a driving method thereof. The disclosed organic light emitting display device and its driving method perform sensing driving for each sub-pixel in a display panel including a plurality of sub-pixels to obtain a sensed value, and the obtained sensed value is applied to a sensing line (reference voltage line). By compensating for the deviation of the characteristic values of the existing sensing link lines, accurate data compensation and poor image quality are prevented.

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, pixels including organic light emitting diodes are arranged in a matrix form, and brightness of pixels selected by a scan signal is controlled according to a gray level of data.

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

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. However, even when a sensing value for each sub-pixel is obtained for compensating for a characteristic value deviation, there is a characteristic value deviation such as capacitance between sensing lines (eg, reference voltage lines) from which a sensing value is obtained, so there is a problem in that an accurate sensing value cannot be obtained.

As described above, although sensing driving is performed to compensate for the characteristic value deviation between sub-pixels, a changed sensing value is obtained due to the characteristic value deviation existing in the sensing lines, thereby causing a problem in image quality.

According to the present invention, after sensing driving for each sub-pixel, by compensating for a characteristic value deviation existing in a sensing line (reference voltage line) with respect to the obtained sensing value, it is possible to obtain a sensing value (sensing data) with high reliability. An object of the present invention is to provide a light emitting display device and a driving method thereof.

In addition, the present invention provides an organic light emitting display device and a method of driving the same, in which accurate data compensation and poor image quality are prevented by compensating for a characteristic value deviation existing between link lines for sensing lines with respect to a sensing value obtained by sensing driving. It serves another purpose to provide.

The organic light emitting display device of the present invention for solving the problems of the prior art as described above includes a display panel in which a plurality of data lines and a plurality of gate lines are disposed, and a plurality of subpixels are disposed in a metric type, and the plurality of data lines a data driver for driving a line, a gate driver for driving the plurality of gate lines, and a controller for controlling the data driver and the gate driver, wherein each subpixel includes an organic light emitting diode and driving the organic light emitting diode a driving transistor, a switching transistor electrically connected between a first node of the driving transistor and a data line supplying the data voltage, and a sensing transistor electrically connected between a second node of the driving transistor and a reference voltage line and a storage capacitor electrically connected between the first node and the second node of the driving transistor, and a sensing value is acquired through a sensing line to compensate for deviation in characteristics of the driving transistors disposed in each of the subpixels. and a compensator for acquiring a compensation sensing value in consideration of the deviation of the characteristic value of the sensing line with respect to the acquired sensing value, thereby enabling a highly reliable sensing value (sensing data) to be obtained.

Further, in the method of driving an organic light emitting display device of the present invention, an organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a first node of the driving transistor and a data line for supplying a data voltage are electrically connected A sub-pixel including a switching transistor configured to be a switching transistor, a sensing transistor electrically connected between a second node of the driving transistor and a reference voltage line, and a storage capacitor electrically connected between the first node and a second node of the driving transistor In the driving method of an organic light emitting display device comprising the plurality of display panels, a data driver outputting the data voltage to the data line, and a controller controlling the data driver, a difference in characteristic values of each sub-pixel is compensated for performing sensing to obtain a sensing value for each sub-pixel by performing the sensing, and obtaining a compensation sensing value by calculating the obtained sensing value and link line characteristic value information of the sensing line and compensating for data using the compensation sensing value, thereby having the effect of accurately compensating for data and preventing poor image quality.

An organic light emitting display device and a driving method thereof according to the present invention compensate for a characteristic value deviation existing in a sensing line (reference voltage line) with respect to a sensing value obtained after sensing driving of each sub-pixel, thereby providing a high-reliability sensing value (sensing data) has the effect of being able to obtain it.

In addition, the organic light emitting display device and the driving method thereof according to the present invention compensate for a characteristic value deviation existing between link lines for sensing lines with respect to a sensing value obtained by sensing driving, thereby preventing accurate data compensation and poor image quality. There is one effect.

1 is a schematic system configuration diagram of an organic light emitting display device according to the present invention.
2 is an equivalent circuit diagram of a sub-pixel of an organic light emitting diode display according to the present invention.
3 is an exemplary diagram of a sub-pixel compensation circuit of an organic light emitting diode display according to the present invention.
4 is a graph illustrating a voltage change of a sensing node or a first node of a driving transistor during a threshold voltage sensing operation of the organic light emitting diode display according to the present invention.
5 is a diagram illustrating a link area between a data driver and a display panel disposed in an organic light emitting diode display according to the present invention.
6 to 8 are diagrams for explaining a sensing operation of the organic light emitting display device according to the present invention.
9 is a graph of sensing values in which sub-pixel characteristic value deviation compensation is performed and link characteristic value deviation is not taken into account.
10 is a block diagram illustrating a structure of a compensator of an organic light emitting diode display according to the present invention.
11 to 13 are diagrams illustrating link information stored in a lookup table of the compensator according to the present invention.
14 is a graph showing compensation sensing values in consideration of both sub-pixel characteristic value deviation compensation and link characteristic value deviation according to the present invention.
15 is a flowchart illustrating a method of compensating an organic light emitting diode display by considering both sub-pixel characteristic value deviation compensation and link characteristic value deviation 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, the case in which the plural is included is 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 , in the organic light emitting diode display 100 according to the present invention, a plurality of data lines DL and a plurality of gate lines GL are disposed, and a plurality of subpixels SP are disposed in a matrix type. display panel 110, a data driver 120 that drives a plurality of data lines by supplying data voltages to the plurality of data lines, and a plurality of gate lines by sequentially supplying scan signals to the plurality of gate lines It includes a gate driver 130 that sequentially drives, a data driver 120 , and a controller 140 that controls the gate driver 130 .

The controller 140 supplies various control signals DCS and GCS 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, and converts the input image data input from the outside according to the data signal format used by the data driver 120 to convert the converted image data DATA. output and control the data drive according to the scan.

The controller 140 may be implemented by including at least one timing controller.

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 controller 140 . Here, the gate driver 130 may be referred to as a scan driver.

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.

Each gate driver integrated circuit is connected to a bonding pad of the display panel 110 by a tape automated bonding (TAB) method or a chip-on-glass (COG) method, or a gate in panel (GIP) method. It may be implemented as a type and disposed directly on the display panel 110 , or may be integrated and disposed on the display panel 110 in some cases.

Each gate driver integrated circuit 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 DATA received from the controller 140 into an analog data voltage and supplies it to the data lines, thereby driving a plurality of data lines.

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

Each source driver integrated circuit is connected to a bonding pad of the display panel 110 or connected to the display panel 110 by a tape automated bonding (TAB) method or a chip-on-glass (COG) method. It may be directly disposed or, in some cases, may be integrated and disposed on the display panel 110 .

Each source driver integrated circuit may be implemented in a Chip On Film (COF) method.

In this case, one end of each source driver integrated circuit is bonded to at least one source printed circuit board, and the other end is bonded to the display panel 110 .

Each source driver integrated circuit may include a logic unit including a shift register and a latch circuit, a digital analog converter (DAC), an output buffer, and the like, and in some cases, the characteristics ( Example: A sensing unit (sensor) for sensing characteristics of a sub-pixel may be further included to compensate for the threshold voltage and mobility of the driving transistor, the threshold voltage of the organic light emitting diode, the luminance of the sub-pixel, etc.).

On the other hand, the 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 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, as well as the data driver 120 and the gate driver 130 . In order to control the data driver 120 and the gate driver 130 by receiving a timing signal 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 output as

For example, in order to control the gate driver 130 , the controller 140 includes 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 .

Referring to FIG. 1 , the controller 140 connects the source printed circuit board to which the 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) for supplying various voltages or currents to the display panel 110 , the data driver 120 , the gate driver 130 , or controlling 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).

The source printed circuit board and the control printed circuit board mentioned above may be a single printed circuit board.

In each of the plurality of sub-pixels disposed on the display panel 110 according to the present invention, an organic light emitting diode (OLED) and circuits such as a driving transistor (DRT) and a storage capacitor for driving the organic light emitting diode (OLED) It may basically include an element.

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.

Hereinafter, a sub-pixel structure for sensing characteristic values such as threshold voltage and mobility of the driving transistor DRT, compensation for the sensed value, and data compensation using the same will be exemplarily described.

2 is an equivalent circuit diagram of a subpixel of an organic light emitting diode display according to the present invention, and FIG. 3 is an exemplary diagram of a subpixel compensation circuit of an organic light emitting display device 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) and a driving transistor (DRT) for driving the organic light emitting diode (OLED). ) and the switching transistor SWT connected between the second node N2 of the driving transistor DRT and the data line DL and transferring the data voltage Vdata to the second node N2 of the driving transistor DRT. : Switching Transistor), a storage capacitor (Cst: Storage Capacitor) that maintains a constant voltage for one frame time, and a reference supplying the first node (N1) and the reference voltage (Vref) of the driving transistor (DRT) It may include a sensing transistor (SENT) electrically connected between a reference voltage line (RVL) and the like.

Referring to FIG. 2 , an organic light emitting diode (OLED) includes 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).

As an example, the first electrode of the organic light emitting diode OLED is connected to the first node N1 of the driving transistor DRT, and the second electrode of the organic light emitting diode OLED supplies the base voltage EVSS. can be connected with

Referring to FIG. 2 , the driving transistor DRT supplies a driving current to the organic light emitting diode OLED to drive the organic light emitting diode OLED, and a first node corresponding to a source node or a drain node ( N1), a second node N2 corresponding to a gate node, and a third node N3 corresponding to a drain node or a source node.

For example, the first node N1 of the driving transistor DRT may be electrically connected to the first electrode or the second electrode of the organic light emitting diode OLED.

Also, the first node N1 of the driving transistor DRT may be electrically connected to a source node or a drain node of the sensing transistor SENT. The second node N2 of the driving transistor DRT may be electrically connected to a source node or a drain node of the switching transistor SWT, and the third node N3 is a driving voltage line supplying the driving voltage EVDD. DVL) and may be electrically connected.

Referring to FIG. 2 , the switching transistor SWT is a transistor that transfers a data voltage Vdata to an N2 node corresponding to the gate node of the driving transistor DRT, and includes the N2 node and the data line ( DL) and may be turned on by the scan signal SCAN applied to the gate node to transfer the data voltage Vdata to the N2 node of the driving transistor DRT.

Referring to FIG. 2 , the storage capacitor Cst may be electrically connected between the first node N1 and the second node N2 of the driving transistor DRT.

Referring to FIG. 2 , the sensing transistor SENT is electrically connected between the first node of the driving transistor DRT and the reference voltage line RVL, and is a sense signal SENSE, which is a type of scan signal applied to the gate node. ) can be controlled by Here, any point on the reference voltage line RVL corresponds to the sensing node Ns.

The sensing transistor SENT is turned on to apply the reference voltage Vref supplied through the reference voltage line RVL to the first node N1 of the driving transistor DRT.

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 to receive the same gate signal. 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 is a different gate line signal.

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.

In addition to deviations in characteristics between the driving transistors DRT (threshold voltage deviation, mobility deviation), as well as deviations in characteristics between the organic light emitting diodes (OLEDs) (threshold voltage deviation, etc.) may exist.

In addition, the display panel 110 is divided into an active area (A/A) and a non-active area (NA), and the reference voltage lines RVL are all the same in the active area A/A. Although the reference voltage link lines (Link regions) have different lengths, the link characteristic values have different values.

That is, since the reference voltage line RVL used as a sensing line for obtaining a sensing value also has different characteristic values in the link region, a characteristic value deviation exists between the reference voltage lines RVL.

Here, the deviation of the characteristic value of the reference voltage line RVL occurs in reference voltage link lines having different lengths, and the characteristic value may mean a value of resistance (R), inductance (L), or capacitance (Cap), and the sum of these values It may be an impedance value.

Accordingly, in the present specification, the deviation of the characteristic value between the driving transistors DRT and the deviation of the characteristic value between the organic light emitting diodes (OLED) is summed up as <subpixel characteristic value deviation>, and the deviation of the characteristic values present in the reference voltage lines RVL is calculated. It is called <Link characteristic value deviation>.

Accordingly, in the organic light emitting display device 100 according to the present invention, as shown in FIG. 3 , a sensing configuration capable of sensing the sub-pixel characteristic value deviation and a sub-pixel characteristic value deviation sensing value Vsen, for example, are driven A compensation configuration for compensating the sensed value Vsen based on <link characteristic value deviation> information additionally present in the reference voltage line RVL based on the Vth sensed value of the transistor DRT is included, and this sensing configuration and the sensing value compensation configuration It is possible to provide a sensing driving method and a data compensation method using

The organic light emitting diode display 100 according to the present invention first senses <sub-pixel characteristic value deviation> (also referred to as sub-pixel characteristic value change amount) as shown in FIG. 3 . The sensing configuration is connected through the reference voltage line (RVL) and the second switch (SW2), senses the voltage on the reference voltage line (RVL) that has become a specific voltage state through sensing driving, and converts the sensed voltage into a digital value. It may include a sensing unit 300 for outputting sensing data.

Accordingly, in some cases, the reference voltage line RVL may be referred to as a sensing line, and the reference voltage link line may be referred to as a sensing link line.

The sensing unit 300 may be implemented as an analog-to-digital converter (ADC).

Referring to FIG. 3 , sensing data output by the sensing unit 300 may be stored in the memory 310 or compensated by the compensator 320 and then stored in the memory 310 .

In addition, as shown in FIG. 3 , the organic light emitting display device 100 according to the present invention is a compensation configuration for compensating for <sub-pixel characteristic value deviation> and <link characteristic value deviation>. Compensation sensing data C-Vsen using the output sensing data Vsen and the lookup table 321 including information on the <link characteristic deviation> of the reference voltage lines RVL as shown in FIG. 10 . may include a compensator 320 that generates

That is, in the present invention, a sensing value (sensing data: Vsen) for compensating for <sub-pixel characteristic deviation> is firstly obtained by sensing driving, and then the sensing value is obtained from the compensator 320 secondarily. A compensation sensing value (compensation sensing data: C-Vsen) is generated using the <link characteristic deviation) information present in the sensing line, that is, the reference voltage line RVL, and the compensation sensing value C-Vsen is used to generate reward data.

Therefore, in the present invention, data compensation is performed in consideration of both the <sub-pixel characteristic value deviation> present in each sub-pixel and the <link characteristic value deviation> present in the reference voltage lines (RVL), thereby providing more reliable sensing driving and It has the effect of improving the picture quality.

The compensation sensing value C-Vsen may be stored in the memory 310 , and the compensation unit 320 may be included in the controller 140 .

The compensator 320 or the controller 140 uses the compensation sensing value C-Vsen calculated by the compensator 320 to change the data to be supplied to the corresponding sub-pixel and transmits the changed data to the data driver 120 . supplied with Accordingly, the subpixel characteristic value deviation and the link characteristic value deviation compensation are actually performed together.

For example, the changed data is obtained by adding the sub-pixel characteristic deviation (change amount: threshold voltage or threshold voltage change amount) to the original data, and then <link characteristic value deviation> (capacitance (Cap), inductance (L), resistance (R)) , etc.) can be multiplied.

As described above, in the organic light emitting display device and the driving method thereof according to the present invention, by compensating for a characteristic value deviation existing in a sensing line (reference voltage line) with respect to a sensing value obtained after sensing driving of each sub-pixel, reliability, There is an effect that a high sensing value (sensing data) can be obtained.

In addition, the organic light emitting display device and the driving method thereof according to the present invention compensate for a characteristic value deviation existing between link lines for sensing lines with respect to a sensing value obtained by sensing driving, thereby preventing accurate data compensation and poor image quality. one effect.

Hereinafter, a sensing principle of the threshold voltage (or threshold voltage variation) of the driving transistor DRT will be briefly described with reference to FIG. 4 .

4 is a graph illustrating a voltage change of a sensing node or a first node of a driving transistor during a threshold voltage sensing operation of the organic light emitting diode display according to the present invention.

Referring to FIG. 4 , the threshold voltage sensing operation of the organic light emitting diode display 100 according to the present exemplary embodiments may be performed through an initialization step S410 , a voltage following step S420 , and a sensing step S430 .

In the initialization step S410 , the first node N1 and the second node N2 of the driving transistor DRT are initialized to the data voltage Vdata and the reference voltage Vref, respectively.

In the initialization step S410 , the switching transistor SWT is turned on and the data voltage Vdata is applied to the second node N2 of the driving transistor DRT. And, the first switch SW1 connecting the reference voltage line RVL and the reference voltage supply node Nref is turned on, and is driven through the reference voltage line RVL and the turned-on sensing transistor SENT. The reference voltage Vref is applied to the first node N1 of the transistor DRT.

Referring to FIG. 4 , in the voltage following step S420 , the first node N1 of the driving transistor DRT is made to float. Accordingly, the voltage of the first node N1 of the driving transistor DRT increases while following the voltage of the second node N2.

The voltage of the first node N1 of the driving transistor DRT rises and becomes saturated after a certain period of time.

The sensing step S430 is a step performed when the voltage of the first node N1 of the driving transistor DRT rises and then becomes saturated.

In the sensing step S430 , the second switch SW2 is turned on, and the sensing unit 300 senses the voltage of the reference voltage line RVL.

In this case, the sensed value Vsen may be expressed as a known data voltage Vdata and a desired threshold voltage Vth (Vsen=Vdata-Vref).

That is, the sensing value Vsen is a primary value obtained by sensing driving to compensate for <sub-pixel characteristic value deviation>, and in the present invention, the compensation unit 320 sets the reference voltage line RVL with respect to the sensing value Vsen. ) of the <link characteristic value deviation> information is obtained secondary to the compensation sensing value (C-Vsen), and then data compensation is performed using it.

As described above, the present invention compensates for a characteristic value deviation existing in a sensing line (reference voltage line) with respect to an acquired sensing value after sensing driving for each sub-pixel, so that a high-reliability sensing value (sensing data) can be obtained. one effect.

5 is a diagram illustrating a link region between a data driver and a display panel disposed in an organic light emitting display device according to the present invention, and FIGS. 6 to 8 are views for explaining a sensing operation of the organic light emitting display device according to the present invention. , FIG. 9 is a graph of a sensing value in which sub-pixel characteristic value deviation compensation is performed and link characteristic value deviation is not considered.

Referring to FIGS. 5 to 9 together with FIG. 1 , a plurality of source driver integrated circuits 121 are disposed in the data driver 120 of the organic light emitting diode display 100 of the present invention.

As shown in the drawing, the source driver integrated circuit 121 may be disposed on the data driver 120 separately from the display panel 110 , or may be directly mounted on the non-display area NA of the display panel 110 . can

In the source driver integrated circuit 121 , a plurality of data lines DL and reference voltage lines RVL are disposed to correspond to respective subpixel columns of the display area A/A via a link area Link. do.

The first to nth data lines D1, D2, D3, D4, D5, D6, D7, ...Dn and the first to mth reference voltage lines RVL1, RVL2 are provided from the arbitrary source driver integrated circuit 121 . , RVL3, ..., RVLm) are drawn out and can be seen as extending to the display area A/A of the display panel 110 .

Since the data lines DL and the reference voltage lines RVL disposed in the display area A/A of the display panel 110 are formed to have the same length and width as each other, the characteristic values of resistance, inductance, or capacitance are different. have almost the same value.

However, each of the link lines disposed in the link region Link of the display panel 110 and integrally formed with the data lines DL or the reference voltage lines RVL is a source driver integrated circuit. Since they have a predetermined slope from the front end of the display area A/A from 121 , the lengths L of the link lines have different values. Due to this, the characteristic values of the link lines have a predetermined deviation from each other.

That is, the resistance (R), inductance (L), or capacitance (Cap) of each of the link lines have different values, so that the reference voltage link lines of the reference voltage lines RVL have link characteristic values. will have a deviation.

Although the drawing shows a case in which the source driver integrated circuit 121 is mounted in the non-display area N/A of the display panel 110 , the source driver integrated circuit is installed in the data driver 120 separated from the display panel 110 . Even when 121 is mounted, link lines exist in the non-display area N/A of the display panel 110 . Accordingly, the description of FIG. 5 may be equally applied even when the source driver integrated circuit 121 is mounted on the data driver 120 separated from the display panel 110 .

Referring to FIG. 5 , taking the reference voltage line RVL as an example, the link line of the first reference voltage line RVL1 has a length of L1 and the link line of the second reference voltage line RVL2 is has a length of L2, and the link line of the mth reference voltage line RVLm has a length of Lm.

Accordingly, the link characteristic value of the first reference voltage line RVL1 is equalized to capacitance and resistance values, and the values are Cap1 and R1. In addition, the link characteristic values of the second reference voltage line RVL2 become Cap2 and R2, and the link characteristic values of the mth reference voltage line RVLm become Capm and Rm. Although not clearly indicated in the drawings, the inductance (L) values also have different values, but are not indicated here.

As described above, since the link lines of the reference voltage lines RVL have different lengths, there is a <link characteristic deviation> between the reference voltage lines RVL. Due to this <link characteristic value deviation>, the subpixel characteristic value deviation Even if the sensing value Vsen for compensation is obtained, the obtained sensing value Vsen does not become an accurate sensing value due to <link characteristic deviation>.

6 to 8 , the driving method for sensing the threshold voltage of the driving transistor DRT disposed in the subpixel SP shown in FIG. 3 includes an N1 node (gate node) of the driving transistor DRT. and an initialization step (Initial) to initialize the voltage of the N2 node (source node or drain node), and a program to increase the voltage of the N2 node of the driving transistor (DRT) by floating the N2 node of the driving transistor (DRT) and a sensing step (Program, Sensing) and a sampling step (Sampling) of sensing the saturation voltage of the N2 node of the driving transistor DRT when the voltage of the N2 node of the driving transistor DRT rises and saturates.

In the initialization step Initial, the scan signal SCAN is applied to the gate node of the switching transistor SWT, and the switching transistor SWT is turned on. Also, in the programming stage, the sense signal SENSE is applied to the gate node of the sensing transistor SENT, and the sensing transistor SENT is turned on.

6 and 7 , in the initialization step Initial, the data voltage Vdata supplied to the data line DL is applied to the N1 node of the driving transistor DRT through the turned-on switching transistor SWT. do.

6 and 7 , in the initialization step Initial, the first switch SW1 is turned on and the reference voltage Vref is supplied to the reference voltage line RVL. The reference voltage Vref supplied to the reference voltage line RVL is applied to the N2 node of the driving transistor DRT through the turned-on sensing transistor SENT.

Accordingly, in the initialization step Initial, the N1 node (gate node) of the driving transistor DRT is initialized with the data voltage Vdata, and the N2 node (source node or drain node) of the driving transistor DRT is set to the reference voltage ( Vref) is initialized.

Accordingly, as shown in FIG. 7 , in the initialization step Initial, the voltage of the reference voltage line RVL corresponding to the sensing line corresponds to the reference voltage Vref.

6 and 7, in the programming and sensing steps (Program, Sensing) performed after the initialization step (Initial), the scan signal (SCAN) is continuously applied to the gate node of the switching transistor (SWT), the switching transistor ( SWT) remains on.

In addition, the sense signal SENSE is also continuously applied to the gate node of the sensing transistor SENT, so that the sensing transistor SENT may also maintain an on state.

However, in the programming step and the sensing step (Sensing), the first switch SW1 is turned off, so that the reference voltage Vref is not supplied to the reference voltage line RVL. Accordingly, the N2 node of the driving transistor DRT is floated.

Referring to FIG. 6 , as the N2 node of the driving transistor DRT floats, the voltage of the N2 node of the driving transistor DRT starts to rise from the reference voltage Vref.

The voltage increase of the N2 node of the driving transistor DRT is performed until a difference between the data voltage Vdata and the constant voltage Vth is increased.

6 to 8 , in the sensing and sampling steps, the N2 node of the driving transistor DRT is in a state in which the sense signal SENSE is applied to the gate node of the sensing transistor SENT. When the voltage is sufficiently increased, the second switch SW2 is turned on in the sampling step (Sampling), and the N2 node voltage of the driving transistor DRT is sensed through the reference voltage line RVL corresponding to the sensing line. is sensed

The sensing unit 300 includes an analog-to-digital converter (ADC), and in this case, the sensed voltage Vsen is “Vdata-Vth”.

However, as shown in FIG. 6 , the Vth sensing and compensation method of the driving transistor DRT devotes sufficient sensing time to minimize the effect on mobility, which causes a problem in that the sensing time becomes longer. , a method to reduce the sensing time has been proposed. This is because, if the sensing time is long, there is a problem in product performance.

As shown in FIG. 6 , when the sensing time is reduced, the curve of the sensing value Vsen: VN1N2 rapidly changes from the dotted line to the solid line, and the voltage VN1N2 at the N1 node and the N2 node of the driving transistor increases.

As such, when the voltage VN1N2 of the N1 node and the N2 node of the driving transistor increases, a large current I flows to the reference voltage line RVL through the sensing transistor SENT as shown in FIG. , as described with reference to FIG. 5 , different voltage drops occur in each reference voltage line RVL due to the deviation of the link characteristic value in the link line region.

Accordingly, as shown in FIG. 8 , a problem occurs that the sensing value Vsen obtained while the second switch SW2 is turned on in the sampling step varies for each reference voltage line RVL.

That is, although the threshold voltage Vth of the driving transistor DRT is normally sensed, the sensing value Vsen obtained by the sensing unit 300 is changed by <link characteristic value deviation> present in each of the reference voltage lines RVL. Therefore, an accurate sensing value (Vsen) cannot be obtained.

9 is a case in which source driver integrated circuits having 192 channels are used, and X position indicates the number of channels.

Referring to FIG. 9 , as described in FIGS. 3 and 4 , sensing driving is performed to compensate for <sub-pixel characteristic value deviation> and a sensing value Vsen, which is the threshold voltage Vth of the driving transistor DRT, is obtained. , it can be seen that each of the sensing values Vsen is different between the source driver integrated circuits. (Update) Here, Initial is the waveform of the initial sensing value Vsen.

6 and 7, when the sensing time is reduced, the voltage VN1N2 before the sensing value Vsen is obtained increases, so that the voltage drop is larger in the reference voltage line due to the link characteristic value.

That is, when the sensing time is reduced, the sensing values Vsen sensing the threshold voltage Vth of the driving transistor DRT disposed in each subpixel become large due to the <link characteristic deviation> present in the reference voltage lines RVL. deviation occurs.

In addition, if data compensation is performed based on the sensing value Vsen in which the deviation is generated, data compensation is not performed accurately and thus image quality is deteriorated.

Accordingly, as shown in FIG. 8 , in the organic light emitting display device of the present invention, the compensation unit 320 compensates the <link characteristic value deviation> of the sensing value Vsen obtained by sensing driving for <sub-pixel characteristic value deviation> compensation. By generating a compensation sensing value (Vsen) based on the .

Additional compensation for the sensed value Vsen in the compensation unit 320 will be described in detail below.

10 is a block diagram illustrating a structure of a compensating unit of an organic light emitting diode display according to the present invention, and FIGS. 11 to 13 are diagrams showing link information stored in a lookup table of the compensating unit according to the present invention.

Referring to FIGS. 10 to 13 together with FIGS. 3 and 6 , the organic light emitting display device of the present invention includes a sensing value storage unit 322 for storing the sensing value Vsen obtained by the sensing unit 300 ; As shown in FIG. 5 , a lookup table 321 for <link characteristic value deviations> of each link line in the link line region of the reference voltage line RVL, and a link characteristic value deviation of the lookup table 321 It includes a calculation unit 323 that calculates the values and the sensed value Vsen, and a compensation value generation unit 324 that generates a compensation sensed value C-Vsen based on the calculation information of the calculation unit 323 .

The lookup table 321 may include capacitance information for link lines of reference voltage lines RVL based on FIG. 5 . For example, as shown in FIG. 11 , the capacitance Cap1 of the link line L1 of the first reference voltage line RVL1, the capacitance Cap2 of the link line L2 of the second reference voltage line RVL2, It may be composed of deviation values of characteristic values composed of capacitances Capm of the link line Lm of the mth reference voltage line RVLm.

However, since this is not fixed, as in FIG. 12 , the resistance R1 of the link line L1 of the first reference voltage line RVL1 and the resistance of the link line L2 of the second reference voltage line RVL2 are (R2), may be composed of deviation values of characteristic values composed of resistors Rm of the link line Lm of the mth reference voltage line RVLm.

In addition, the impedance Z1 of the link line L1 of the first reference voltage line RVL1, the impedance Z2 of the link line L2 of the second reference voltage line RVL2, and the mth reference voltage line RVLm It may be composed of deviations of characteristic values composed of impedances Zm of the link line Lm of .

The impedance Z is a resistance concept, but here, it may be a value expressed as an absolute value in consideration of the resistance R, the inductance L, and the capacitance C formed in the link line of the reference voltage line RVL. This is because, since the sensing value Vsen primarily acquired through the reference voltage line RVL is in an analog form, a characteristic value can be given in the form of an impedance Z including a frequency concept.

Accordingly, in the organic light emitting display device of the present invention, after the sensing unit 300 acquires the sensing value Vsen, as shown in FIGS. 6 and 8 , in order to primarily compensate for the <sub-pixel characteristic value deviation>, it is The data is not compensated by using the data, and is stored in the sensing value storage unit 322 disposed in the compensation unit 320 . The sensing value Vsen passed through the sensing unit 300 may be referred to as digital sensing data, but will be described as the sensing value Vsen.

Then, as described with reference to FIGS. 5 and 11 to 13 , the calculation unit 323 calculates <link characteristic value deviation> information about the reference voltage lines RVL for obtaining the sensing value Vsen and the sensing value Vsen. calculate in

For example, the compensation sensing value C-Vsen may be obtained by multiplying the sensing value Vsen obtained by the sensing driving method by the capacitance Cap ratio information for each reference voltage line RVL of FIG. 11 . However, since this is not fixed, the capacitance (Cap) information (link characteristic value information) for each reference voltage line (RVL) is reflected in various calculation methods based on the sensed value (Vsen), and then a calculation method in which image quality deviation does not occur is selected. can

In the same manner, when the resistance (R) information or impedance (Z) information and the sensing value Vsen for each reference voltage line RVL shown in FIGS. 12 and 13 are calculated in the same manner. As such, in the present invention, various characteristic values existing in the reference voltage line (RVL: sensing line) for obtaining the sensing value Vsen can be considered, so that the characteristic value deviation compensation that has the most influence on the changed sensing value Vsen is compensated. There are advantages to being able to That is, there is an effect of more precisely compensating for the changed sensing value Vsen.

As described above, the compensation value generation unit 324 generates a compensation sensing value C-Vsen for data compensation based on the value calculated by the calculation unit 323, and compensates the data using the generated compensation value C-Vsen. The compensated data is supplied to the display panel 110 to display an image. In this case, the compensation sensed value C-Vsen generated by the compensation value generator 324 may be stored in the sensed value storage 322 or the storage 310 shown in FIG. 3 .

As described above, in the organic light emitting display device and the driving method thereof according to the present invention, by compensating for a characteristic value deviation existing in a sensing line (reference voltage line) with respect to a sensing value obtained after sensing driving of each sub-pixel, reliability There is an effect that a high sensing value (sensing data) can be obtained.

In addition, the organic light emitting display device and the driving method thereof according to the present invention compensate for a characteristic value deviation existing between sensing link lines for sensing lines with respect to a sensing value obtained by sensing driving, thereby correcting data compensation and poor image quality. has a preventive effect.

14 is a graph showing compensation sensing values in consideration of both sub-pixel characteristic value deviation compensation and link characteristic value deviation according to the present invention. The figure shows a case where source driver integrated circuits having 192 channels are used, and X position indicates the number of channels.

Referring to FIG. 14 , the sensing values Vsen for compensating for the <sub-pixel characteristic value deviation> for each sub-pixel have a more uniform graph than the initial sensing value (Initial), but the sensing values ( Vsen) it can be seen that a deviation occurs. (Update, see Fig. 9)

However, as in the present invention, the compensation sensing values C-Vsen obtained by performing <link characteristic deviation> compensation of the reference voltage line for additionally acquiring the sensing value Vsen with respect to the sensing value Vsen are the source driver integrated circuits. It can be seen that there is no deviation between them. (Invention)

That is, in the present invention, the sensing operation is performed to compensate for the normal <sub-pixel characteristic value deviation>, but the sensing value Vsen is changed due to the <link characteristic value deviation> of the sensing line (reference voltage line) that obtains the sensing value Vsen. The occurrence of deviation of the sensing value (Vsen) was prevented by additionally compensating for the

In this way, when data is compensated based on the sensing value C-Vsen from which the deviation is removed, that is, the compensation sensing value C-Vsen, and then an image is displayed on the display panel, due to the deviation of the conventional sensing value Vsen There is an effect that can remove the image quality defect that has occurred.

15 is a flowchart illustrating a method of compensating an organic light emitting diode display by considering both sub-pixel characteristic value deviation compensation and link characteristic value deviation according to the present invention.

Referring to FIG. 15 , in the sensing and driving method of the organic light emitting diode display 100 according to the present invention, sensing driving is performed to compensate for <sub-pixel characteristic value deviation> for each sub-pixel to be sensed (S1501). . Sensing for compensating for the <sub-pixel characteristic value deviation> follows the description of FIGS. 3 and 4 .

As described above, when sensing is performed to compensate for <sub-pixel characteristic deviation>, characteristic values for each sub-pixel, in this case, the threshold voltage Vth, are acquired from the reference voltage line (S1502).

Then, by using the compensator having the components shown in FIG. 10 , the sensing value Vsen and link characteristic value information present in the reference voltage line (sensing line) are calculated, and the sensing value Vsen is < Link characteristic value deviation> compensation is performed (S1503).

As described above, the <link characteristic value deviation> compensation is performed to obtain a compensated sensing value (C-Vsen), and the display panel is driven by compensating the data using the compensation (S1504, S1505).

According to the above-described sensing driving method of the present invention, after sensing for <subpixel characteristic value deviation> compensation is performed for each subpixel, <link characteristic value deviation> compensation is performed on the sensed value Vsen, thereby changing the sensing value (Vsen) can be compensated.

In this way, when the sensing value Vsen is compensated to obtain a compensated sensing value C-Vsen, data compensation is performed based on this, and thus data compensation by the sensing value Vsen that has not been compensated for <link characteristic deviation> A higher quality image can be realized.

The above description and the accompanying drawings are merely illustrative of the technical spirit 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 driver
130: gate driver
140: timing controller
300: sensor unit
320: compensation unit
321; lookup table
322: sensing value storage unit
323: arithmetic unit
324: compensation value generator

Claims (10)

a display panel in which a plurality of data lines and a plurality of gate lines are disposed, and a plurality of subpixels are disposed in a matrix type;
a data driver driving the plurality of data lines;
a gate driver driving the plurality of gate lines; and
a controller for controlling the data driver and the gate driver;
Each sub-pixel is
An organic light emitting diode, a driving transistor for driving the organic light emitting diode, a switching transistor electrically connected between a first node of the driving transistor and a data line for supplying a data voltage, a second node of the driving transistor and a reference A sensing transistor electrically connected between voltage lines, and a storage capacitor electrically connected between a first node and a second node of the driving transistor,
A sensing value is obtained through a sensing line to compensate for deviation in characteristic values of the driving transistors disposed in each sub-pixel, and a compensation sensing value is calculated in consideration of the deviation of the characteristic value of the sensing link line of the sensing line with respect to the obtained sensing value. An organic light emitting display device including a compensator to acquire. According to claim 1,
The compensation unit,
a lookup table for storing characteristic value information of each sensing line;
a sensing value storage unit for storing the sensing value;
a calculating unit for calculating the sensing value and characteristic value information of a sensing line corresponding to the sensing value;
and a compensation value generator configured to generate a compensation sensing value by using the value calculated by the calculator. According to claim 1,
The sensing line is a reference voltage line. According to claim 1,
The sensing link line characteristic value of the sensing line is any one of capacitance, resistance, and impedance of a sensing link line of the sensing line integrally disposed in a non-display area of the display panel. 5. The method of claim 4,
The sensing link line of the sensing line is a reference voltage link line of the reference voltage line. According to claim 1,
The characteristic value of the driving transistor is a threshold voltage or mobility. An organic light emitting diode, a driving transistor for driving the organic light emitting diode, a switching transistor electrically connected between a first node of the driving transistor and a data line for supplying a data voltage, a second node of the driving transistor and a reference a display panel including a plurality of subpixels including a sensing transistor electrically connected between voltage lines and a storage capacitor electrically connected between a first node and a second node of the driving transistor; A method of driving an organic light emitting display device comprising: a data driver for outputting a voltage; and a controller for controlling the data driver, the method comprising:
Sensing to compensate for the characteristic value deviation of each sub-pixel;
performing the sensing to obtain a sensed value for each subpixel;
obtaining a compensation sensing value by calculating the obtained sensing value and link line characteristic value information of the sensing line;
and compensating for data using the compensation sensing value. 8. The method of claim 7,
The characteristic value of the sensing line is any one of capacitance, resistance, and impedance of a sensing link line of the sensing line integrally disposed in a non-display area of the display panel. 9. The method of claim 8,
The method of driving an organic light emitting display device, wherein the compensation for the variation in the characteristic value of each sub-pixel is compensation for the variation in the characteristic value of a driving transistor disposed in each sub-pixel. 10. The method of claim 9,
A characteristic value of the driving transistor is a threshold voltage or mobility.

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