KR20170026929A - Organic light emitting display device and method for driving the same - Google Patents

Abstract

According to the present invention, an organic light emitting display device and a driving method thereof are disclosed. The organic light emitting display device and the driving method thereof obtain a sensing value by driving sensing for each subpixel on a display panel having a plurality of subpixels, and compensate a characteristics variation of a sensing link line present in a sensing line (reference voltage line) on the obtained sensing value, thereby having an effect of accurately compensating data and preventing an image quality defect.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) display device,

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

2. Description of the Related Art In recent years, an organic light emitting diode (OLED) display device that has been spotlighted as a display device has advantages of high response speed, high luminous efficiency, high luminance and wide viewing angle by using an organic light emitting diode (OLED)

Such an organic light emitting display device arranges pixels including organic light emitting diodes in a matrix form and controls the brightness of pixels selected by a scan signal according to data gradation.

Each subpixel disposed in the organic light emitting display panel of the organic light emitting diode display device is basically composed of a driving transistor for driving the organic light emitting diode, a switching transistor for transmitting the data voltage to the gate node of the driving transistor, And a storage capacitor serving to maintain a predetermined voltage.

Each of the sub-pixel driving transistors becomes degraded as the driving time becomes longer, and characteristic values such as threshold voltage and mobility can be changed. In addition, since the degree of deterioration may be different for each driving transistor, a characteristic value deviation between driving transistors in each sub-pixel may occur.

Since the deterioration of the organic light emitting diodes in each subpixel also progresses as the driving time increases, the characteristic values such as the 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 characteristic value deviation between the subpixels caused by the characteristic value deviation between the driving transistors and the characteristic value deviation between the organic light emitting diodes causes a luminance deviation between the subpixels, which causes a screen abnormal phenomenon such as afterimage of the screen, It is possible to cause non-uniformity.

Thus, a technique for compensating for the deviation of characteristic values between subpixels has been developed. However, even if the sensing value for each subpixel is obtained in order to compensate the characteristic value deviation, there is a characteristic value deviation such as a capacitance between the sensing line (for example, the reference voltage line) for obtaining the sensing value, and an accurate sensing value can not be obtained.

In this way, although the sensing drive is performed to compensate for the characteristic value deviation between the subpixels, a fluctuated sensing value is obtained due to the characteristic value deviation existing in the sensing lines, thereby causing a problem of causing image quality failure.

The present invention provides an organic EL display device capable of obtaining a reliable sensing value (sensing data) by compensating a characteristic value deviation existing in a sensing line (reference voltage line) with respect to an obtained sensing value after sensing driving for each subpixel Emitting display device and a method of driving the same.

The present invention also provides an organic light emitting display device and a method of driving the same that compensate for a characteristic value deviation existing between the link lines to the sensing lines with respect to a sensing value obtained by the sensing drive, There are other purposes to provide.

According to an aspect of the present invention, there is provided an OLED display device including a display panel in which a plurality of data lines and a plurality of gate lines are arranged and a plurality of subpixels are arranged in a matrix type, A gate driver for driving the plurality of gate lines, and a controller for controlling the data driver and the gate driver, wherein each of the sub pixels includes an organic light emitting diode, A switching transistor electrically connected between the first node of the driving transistor and the data line supplying the data voltage; and a sensing transistor electrically connected between the second node of the driving transistor and the reference voltage line, And a second node And a storage capacitor electrically connected between the first node and the second node, wherein a sensing value is obtained through a sensing line to compensate for characteristic deviation of driving transistors disposed in each subpixel, And a compensation unit for obtaining a compensation sensing value in consideration of a characteristic value deviation of the sensing line, thereby providing a reliable sensing value (sensing data).

According to another aspect of the present invention, there is provided a method of driving an organic light emitting diode display device including an organic light emitting diode, a driving transistor for driving the organic light emitting diode, and a data line for supplying a data voltage to the first node of the driving transistor. A sensing transistor electrically connected between a second node of the driving transistor and the reference voltage line and a storage capacitor electrically connected between the first node and the second node of the driving transistor, A data driver for outputting the data voltage to the data line, and a controller for controlling the data driver, the driving method comprising the steps of: compensating a characteristic value deviation of each subpixel And a sensing step for sensing Obtaining a sensing value for each subpixel; calculating a compensation sensing value by operating the obtained sensing value and link line characteristic value information of the sensing line; and compensating the data using the compensation sensing value By including the step, accurate data compensation and image quality defects are prevented.

The organic light emitting display device and the driving method thereof according to the present invention compensate a characteristic value deviation existing in a sensing line (reference voltage line) with respect to an obtained sensing value after sensing driving for each subpixel, (Sensing data) can be obtained.

Also, the OLED display and the driving method thereof according to the present invention compensate characteristic deviation existing between the link lines to the sensing lines with respect to the sensing value obtained by the sensing driving, thereby preventing accurate data compensation and image quality defect There is an effect.

1 is a schematic system configuration diagram of an organic light emitting diode display according to the present invention.
2 is an equivalent circuit diagram of a subpixel of an organic light emitting display according to the present invention.
3 is an exemplary diagram of a subpixel compensation circuit of an organic light emitting display according to the present invention.
4 is a graph illustrating a voltage change of a first node of a sensing node or a driving transistor in a threshold voltage sensing operation of the organic light emitting diode display according to the present invention.
5 is a view illustrating a link area between a data driver and a display panel disposed in the OLED display according to the present invention.
6 to 8 are views for explaining the sensing operation of the organic light emitting diode display according to the present invention.
9 is a graph for a sensing value that proceeds with subpixel characteristic value deviation compensation and does not consider the link characteristic value deviation.
10 is a block diagram showing the structure of the compensation unit of the organic light emitting diode display of the present invention.
11 to 13 are diagrams showing link information stored in the look-up table of the compensating unit of the present invention.
FIG. 14 is a graph illustrating compensation sensing values in which sub-pixel characteristic value deviation compensation and link characteristic value deviation are considered together according to the present invention.
FIG. 15 is a flowchart illustrating a method of compensating an OLED display in consideration of sub-pixel feature value deviation compensation and link characteristic value deviation according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if a temporal posterior relationship is described by 'after', 'after', 'after', 'before', etc., 'May not be contiguous unless it is used.

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

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

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

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

1, an OLED display 100 according to the present invention includes a plurality of data lines DL and a plurality of gate lines GL, a plurality of subpixels SP arranged in a matrix type, A data driver 120 for driving a plurality of data lines by supplying a data voltage to a plurality of data lines and a plurality of gate lines by sequentially supplying scan signals to the plurality of gate lines, A gate driver 130 that sequentially drives the controller, a controller 140 that controls the data driver 120 and the gate driver 130, and the like.

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 in accordance with the timing implemented in each frame, switches the input image data input from the outside according to the data signal format used by the data driver 120, and outputs the converted image data (DATA) And controls the data driving according to the scan.

The controller 140 may be implemented with 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.

1, the gate driver 130 may be located on only one side of the display panel 110, or may be located on both sides, depending on the driving system.

In addition, the gate driver 130 may include one or more gate driver integrated circuits.

Each gate driver integrated circuit may be 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 may be connected to a GIP (Gate In Panel) Type, and may be directly disposed on the display panel 110, and may be integrated and disposed on the display panel 110, as the case may be.

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

When the specific gate line is opened, the data driver 120 converts the image data (DATA) received from the controller 140 into analog data voltages and supplies the data voltages to the data lines to drive the 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 may be connected to a bonding pad of the display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) And may be integrated and disposed on the display panel 110 as occasion demands.

Each source driver integrated circuit can be implemented by 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 portion including a shift register, a latch circuit, etc., a digital analog converter (DAC), an output buffer, and the like, For example, a threshold voltage and a mobility of a driving transistor, a threshold voltage of an organic light emitting diode, a luminance of a subpixel, and the like).

On the other hand, the controller 140 outputs various kinds of signals including the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, the input data enable signal (DE), and the clock signal (CLK) Timing signals from the outside (e.g., the host system).

The controller 140 outputs the converted image data by switching the input image data inputted from the outside in accordance with the data signal format used by the data driver 120 and outputs the converted image data to the data driver 120 and the gate driver 130, A timing signal such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, an input DE signal and a clock signal and generates various control signals to control the data driver 120 and the gate driver 130, .

For example, in order to control the gate driver 130, the controller 140 generates a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal GOE Gate Output Enable), and the like.

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 the shift timing of the scan signal (gate pulse). The gate output enable signal GOE specifies the timing information of one or more gate driver ICs.

The controller 140 further includes a source start pulse SSP and a source sampling clock SSC to control the data driver 120 and a source output enable signal SOE And outputs various data control signals (DCS: Data Control Signals).

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 for controlling 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.

1, the 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) Lt; RTI ID = 0.0 > (Printed Circuit Board). ≪ / RTI >

A power controller (not shown) for controlling various voltages or currents to supply or supply various voltages or currents to the display panel 110, the data driver 120, the gate driver 130, . These power controllers are also referred to as power management ICs (PMICs).

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

Each of the plurality of subpixels arranged in the display panel 110 according to the present invention includes an organic light emitting diode (OLED), a driving transistor (DRT) for driving the organic light emitting diode, and a storage capacitor Device can basically be included.

The types and the number of the circuit elements constituting each subpixel can be variously determined depending on a providing function, a design method, and the like.

Hereinafter, a subpixel structure for sensing a characteristic value such as threshold voltage and mobility of the driving transistor DRT, compensating a sensing value, and compensating data using the sensing value will be described as an example.

FIG. 2 is an equivalent circuit diagram of a subpixel of the organic light emitting diode display according to the present invention, and FIG. 3 is an exemplary view of a subpixel compensation circuit of the organic light emitting diode display according to the present invention.

2, each subpixel SP disposed in the display panel 110 according to the present invention includes an organic light emitting diode OLED, a driving transistor DRT driving the organic light emitting diode OLED, A 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; A storage capacitor Cst that serves to maintain a constant voltage for one frame time, a reference voltage Vref for supplying a reference voltage Vref to the first node N1 of the driving transistor DRT, And a sensing transistor (SENT) electrically connected between a voltage line (RVL) and the like.

Referring to FIG. 2, the organic light emitting diode OLED includes a first electrode (e.g., an anode electrode or a cathode electrode), an organic layer, and a second electrode (e.g., a cathode electrode or an anode electrode).

For 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 is connected to the ground voltage Lt; / RTI >

Referring to FIG. 2, the driving transistor DRT is a transistor for driving the organic light emitting diode OLED by supplying a driving current to the organic light emitting diode OLED. The driving transistor DRT includes a first 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 the source node or the drain node of the sensing transistor SENT. The source node or the drain node of the switching transistor SWT may be electrically connected to the second node N2 of the driving transistor DRT and the third node N3 may be coupled to the driving voltage line DVL < / RTI >

2, the switching transistor SWT is a transistor for transferring the data voltage Vdata to the N2 node corresponding to the gate node of the driving transistor DRT. The N2 node of the driving transistor DRT and the data line DL and is turned on by the scan signal SCAN applied to the gate node to transfer the data voltage Vdata to the node N2 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.

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 connected to the sense node SENSE ). ≪ / RTI > Here, an arbitrary point on the reference voltage line RVL corresponds to the sensing node Ns.

The sensing transistor SENT may be 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, the scan signal SCAN and the sense signal SENSE are different gate line signals.

On the other hand, each driving transistor DRT has a characteristic value such as a threshold voltage (Vth) and a mobility. In addition, the driving transistor DRT may be degraded according to the driving time, and the characteristic value may be changed.

There may be not only a characteristic value deviation (threshold voltage deviation, mobility deviation) between the driving transistors DRT but also a characteristic value deviation (threshold voltage deviation, etc.) between the organic light emitting diodes OLED.

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

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

Here, a characteristic value deviation of the reference voltage line RVL is generated in a reference voltage link line having a different length, and the characteristic value thereof may mean a resistance R or an inductance L or a capacitance Cap value, May be an impedance value.

Therefore, in the present specification, a characteristic value deviation existing in the reference voltage lines (RVL) is referred to as a " sub-pixel characteristic value deviation ", which is a sum of the characteristic value deviation between the driving transistors (DRT) and the organic light emitting diode ≪ Link characteristic value deviation >

3, the organic light emitting display 100 according to the present invention includes a sensing structure for sensing a sub-pixel characteristic value deviation and a sub-pixel characteristic value deviation sensing value Vsen, for example, Based on the Vth sensing value of the transistor (DRT), the sensing value (Vsen) based on the information on the <link characteristic value> existing in the reference voltage line (RVL) A sensing driving method and a data compensation method can be provided.

The organic light emitting diode display 100 according to the present invention first senses a <subpixel characteristic value variation> (also referred to as a subpixel characteristic value variation amount) as shown in FIG. The sensing configuration is connected through the reference voltage line RVL and the second switch SW2 to sense a voltage on the reference voltage line RVL that has become a specific voltage state through sensing driving to convert the sensed voltage into a digital value And a sensing unit 300 for outputting sensing data.

Therefore, 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).

3, the sensing data output by the sensing unit 300 may be stored in the memory 310 or may be stored in the memory 310 after being compensated by the compensating unit 320. Referring to FIG.

3, the OLED display 100 according to the present invention has a compensation structure for compensating for the < subpixel characteristic value deviation > and the < link characteristic value deviation & The compensation sensing data C-Vsen is calculated using the output sensing data Vsen and the look-up table 321 including information on the <link characteristic value deviation> of the reference voltage lines RVL, as shown in FIG. And a compensation unit 320 for generating a compensation value.

That is, in the present invention, a sensing value (sensing data: Vsen) for compensating for the <sub-pixel characteristic deviation> is first obtained by sensing driving and then the sensing value is secondarily acquired by the compensating unit 320 (Compensation sensing data: C-Vsen) using the information on the sensing line, i.e., the link characteristic value deviation present in the reference voltage line RVL, and using the compensation sensing value C-Vsen Data is compensated.

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> existing in the reference voltage line (RVL) There is an effect of improving 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 compensation unit 320 or the controller 140 may change the data to be supplied to the corresponding sub pixel by using the compensation sensing value C-Vsen calculated by the compensation unit 320, . Accordingly, the sub-pixel characteristic value deviation and the link characteristic value deviation compensation are actually performed together.

(Capacitance Cap, inductance L, and resistance R) after the subpixel property value deviation (the amount of change: the threshold voltage or the threshold voltage variation) is added to the original data, And the like).

As described above, the OLED display according to the present invention and the driving method thereof compensate for the characteristic value deviation existing in the sensing line (reference voltage line) with respect to the obtained sensing value after sensing driving for each subpixel, It is possible to obtain a high sensing value (sensing data).

Also, the OLED display and the driving method thereof according to the present invention compensate characteristic deviation existing between the link lines to the sensing lines with respect to the sensing value obtained by the sensing driving, thereby preventing accurate data compensation and image quality defect There is an effect.

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

4 is a graph illustrating changes in voltage of a first node of a sensing node or a driving transistor in 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 OLED display 100 according to the exemplary embodiments of the present invention may proceed to an initialization step S410, a voltage follow-up 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. The first switch SW1 for connecting the reference voltage line RVL and the reference voltage supply node Nref is turned on so as to be driven through the reference voltage line RVL and the sensing transistor SENT turned- 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 floated. Accordingly, the voltage of the first node N1 of the driving transistor DRT rises 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 time.

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

The sensing value Vsen sensed at this time can be represented by a known data voltage Vdata and a threshold voltage Vth to be known (Vsen = Vdata-Vref).

That is, the sensing value Vsen is a primary value obtained by sensing driving to compensate for the sub-pixel characteristic value deviation. In the present invention, the compensation value of the reference voltage line RVL (C-Vsen) that reflects the <link characteristic value deviation> information of the target pixel (C-Vsen), and then proceeds to compensate the data using the compensation sensing value (C-Vsen).

As described above, according to the present invention, after sensing driving for each sub-pixel, the characteristic value deviation existing in the sensing line (reference voltage line) is compensated for the obtained sensing value so that a reliable sensing value There is an effect.

FIG. 5 is a view showing a link area between a data driver and a display panel disposed in the OLED display according to the present invention. FIGS. 6 to 8 are views for explaining the sensing operation of the OLED display according to the present invention , And FIG. 9 is a graph for a sensing value that proceeds with subpixel characteristic value deviation compensation and does not take into consideration the link characteristic value deviation.

Referring to FIGS. 5 to 9 together with FIG. 1, a plurality of source driver ICs 121 are arranged in a data driver 120 of the OLED display 100 of the present invention.

The source driver integrated circuit 121 may be disposed in the data driver 120 separately from the display panel 110 and may be directly mounted on the non-display area NA of the display panel 110 .

The source driver ICs 121 are arranged such that a plurality of data lines DL and reference voltage lines RVL are arranged in correspondence with respective subpixel columns of the display area A / do.

Dn, D6, D7, ..., Dn), the first to m-th reference voltage lines (RVL1, RVL2 , RVL3, ..., RVLm are drawn out and extended 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, the values of the resistance, inductance, They have almost the same value.

However, the link lines arranged in the link region (Link) of the display panel 110 and formed integrally with the data lines DL or the reference voltage lines RVL are connected to the source driver IC The lengths L of the link lines have different values since they have a predetermined inclination from the display area 121 to the front end of the display area A / A. Thus, the characteristic values of the link lines have a predetermined deviation from each other.

That is, the resistance R, inductance L, or capacitance value of each link line has a different value, so that the reference voltage link lines of the reference voltage lines RVL have a link characteristic value It will have a deviation.

Although the source driver integrated circuit 121 is mounted in the non-display area N / A of the display panel 110 in the drawing, the data driver 120, which is separate from the display panel 110, There are link lines in the non-display area N / A of the display panel 110 even when the display panel 121 is mounted. Therefore, the description of FIG. 5 can be applied to the case where the source driver integrated circuit 121 is mounted on the data driver 120 separated from the display panel 110 as well.

Referring to FIG. 5, the reference voltage line RVL is taken as an example. The link line of the first reference voltage line RVL1 has a length of L1, Has a length of L2, and the link line of the m-th reference voltage line (RVLm) has a length of Lm.

Therefore, the link characteristic value of the first reference voltage line RVL1 is equivalent to the capacitance and the resistance value, and the values are Cap1 and R1. The link characteristic values of the second reference voltage line RVL2 are Cap2 and R2, and the link characteristic values of the m-th reference voltage line RVLm are Capm and Rm. Though not clearly shown in the figure, the inductance L value also has a different value, but is not shown here.

As described above, since the lengths of the link lines of the reference voltage lines RVL are different from each other, a <link characteristic value deviation> is generated between the respective reference voltage lines RVL. Due to such <link 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 the <link characteristic value deviation>.

6 to 8, a driving method for sensing the threshold voltage of the driving transistor DRT arranged in the subpixel SP shown in FIG. 3 includes a step of applying a voltage to the N1 node (gate node) of the driving transistor DRT, And a program for increasing the voltage of the N2 node of the driving transistor DRT by floating the N2 node of the driving transistor DRT, And a sampling step of sensing the saturation voltage of the node N2 of the driving transistor DRT when the voltage of the node N2 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. In the program 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 switching transistor 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 node N2 of the driving transistor DRT through the sensing transistor SENT turned on.

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

Accordingly, as shown in Fig. 7, in the initialization step (Inital), the voltage of the reference voltage line RVL corresponding to the sensing line corresponds to the reference voltage Vref.

Referring to FIGS. 6 and 7, in the program and sensing process after the initialization (Initial), the scan signal SCAN is continuously applied to the gate node of the switching transistor SWT, SWT) remains on.

Also, the sense signal SENSE is continuously applied to the gate node of the sensing transistor SENT, so that the sensing transistor SENT can be maintained in the ON state.

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

Referring to FIG. 6, as the node N2 of the driving transistor DRT is floated, the voltage of the node N2 of the driving transistor DRT begins to rise at the reference voltage Vref.

The voltage rise 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 reached.

6 to 8, in the sensing and sampling stages, in the state where the sense signal SENSE is applied to the gate node of the sensing transistor SENT, the potential of the node N2 of the driving transistor DRT The second switch SW2 is turned on in the sampling step and the N2 node voltage of the driving transistor DRT is applied to the sensing unit 300 through the reference voltage line RVL corresponding to the sensing line, .

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

However, as shown in FIG. 6, the Vth sensing and compensation method of the driving transistor DRT takes a sufficient sensing time to minimize the influence of mobility, which leads to a problem that the sensing time becomes longer , A method for reducing the sensing time has been proposed. This is because if the sensing time becomes longer, there is a problem with the product performance.

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

As described above, when the voltages VN1N2 of the N1 and N2 nodes of the driving transistor increase, a large current I flows through the sensing transistor SENT to the reference voltage line RVL as shown in FIG. 7 As described above with reference to FIG. 5, currents flowing to the reference voltage line RVL in this manner cause different voltage drops in the reference voltage lines RVL due to the link characteristic value deviation in the link line region.

Therefore, as shown in FIG. 8, the sensing value Vsen obtained by turning on the second switch SW2 in the sampling step varies depending on each reference voltage line RVL.

That is, the sensing voltage Vsen of the driving transistor DRT is normally sensed. However, the sensing voltage Vsen obtained by the sensing unit 300 may fluctuate depending on the <link characteristic value deviation> present in each of the reference voltage lines RVL. So that an accurate sensing value (Vsen) can not be obtained.

9 shows the case where source driver integrated circuits having 192 channels are used, and X position indicates the number of channels.

Referring to FIG. 9, as described with reference to FIGS. 3 and 4, when the sensing value Vsen, which is the threshold voltage Vth of the driving transistor DRT, is obtained by advancing the sensing driving for compensating the sub-pixel characteristic value deviation , It can be seen that each sensing value (Vsen) deviates between the source driver integrated circuits (Update), where Initial is the waveform of the initial sensing value (Vsen).

As described with reference to FIGS. 6 and 7, when the sensing time is reduced, the voltage VN1N2 before acquiring the sensing value Vsen becomes large, so that the voltage drop occurs more greatly in the reference voltage line due to the link characteristic value.

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

In addition, if data compensation is performed based on the sensed value (Vsen) in which a deviation is generated, data compensation can not be accurately performed and image quality is defective.

Therefore, as shown in FIG. 8, the organic light emitting display of the present invention compensates for the sensing value Vsen obtained by sensing driving to compensate for the sub-pixel characteristic value deviation from the compensating unit 320, And compensates the data based on the compensated sensing value Vsen, thereby preventing the image quality deterioration that has been conventionally generated.

Additional compensation for the sensing value (Vsen) in the compensation unit 320 will be described in detail below.

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

10 to 13, the OLED display of the present invention includes a sensing value storage unit 322 for storing a sensing value Vsen obtained by the sensing unit 300, A lookup table 321 for the <link characteristic value deviations> of each link line in the link line area of the reference voltage line RVL and a link characteristic value deviation And a compensation value generating unit 324 for generating a compensation sensing value C-Vsen based on the operation information of the calculating unit 323. The compensation value generating unit 324 generates a compensation value C-

The lookup table 321 may be constituted by capacitance information for the link line of the reference voltage lines RVL based on FIG. 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, And the capacitance values Capm of the link line Lm of the m-th reference voltage line RVLm.

12, since the resistor R1 of the link line L1 of the first reference voltage line RVL1 and the resistor R1 of the link line L2 of the second reference voltage line RVL2 are not fixed, The resistance Rm of the link line Lm of the m-th reference voltage line RVLm, and the resistance Rm of the link line Lm of the m-th reference voltage line RVLm.

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 impedances Zm of the link line Lm of the link line Lm.

The impedance Z may be a value represented by an absolute value in consideration of both the resistance R, the inductance L and the capacitance C formed on the link line of the reference voltage line RVL. This is because the sensed value Vsen obtained primarily through the reference voltage line RVL is an analog form, and thus the characteristic value can be given in the form of impedance Z including the frequency concept.

Therefore, in order to compensate for the sub-pixel characteristic value deviation, the OLED display device of the present invention first obtains the sensing value Vsen by the sensing unit 300 as shown in FIGS. 6 and 8, And stores it in the sensing value storage unit 322 disposed in the compensation unit 320 without performing data compensation. The sensing value Vsen via the sensing unit 300 may be referred to as sensing data in a digital form, but it will be described as a sensing value Vsen.

Then, as described in FIG. 5 and FIGS. 11 to 13, the link characteristic value deviation information and the sensing value Vsen for the reference voltage lines RVL for obtaining the sensing value Vsen are calculated by the operation unit 323, .

For example, the compensation value (C-Vsen) can be obtained by multiplying the sensing value (Vsen) obtained by the sensing driving method by the capacitance ratio information per the reference voltage line (RVL) of FIG. However, since this is not fixed, the capacitance information (link characteristic value information) for each reference voltage line (RVL) is reflected in various calculation methods on the basis of the sensing value (Vsen) and then an operation method in which no image quality deviation occurs is selected .

Similarly, when calculating the resistance R information or the impedance Z information and the sensing value Vsen for each reference voltage line RVL shown in FIGS. 12 and 13, the same method can be used. As described above, in the present invention, various characteristic values existing in the reference voltage line (RVL: sensing line) for obtaining the sensing value Vsen can be taken into account, and the characteristic value deviation compensation that has the greatest effect on the changed sensing value Vsen There is an advantage to be able to do. That is, there is an effect that more precise compensation can be performed for the changed sensing value Vsen.

As described above, the compensation value generating unit 324 generates a compensation sensing value (C-Vsen) for data compensation based on the value calculated by the calculating unit 323, and compensates the data using the compensation sensing value (C-Vsen). The compensated data is supplied to the display panel 110 to display an image. At this time, the compensation value C-Vsen generated by the compensation value generating unit 324 may be stored in the sensing value storage unit 322 or the storage unit 310 shown in FIG.

As described above, the OLED display according to the present invention and the driving method thereof compensate for the characteristic value deviation existing in the sensing line (reference voltage line) with respect to the obtained sensing value after sensing driving for each subpixel, It is possible to obtain a high sensing value (sensing data).

Also, the OLED display and the driving method thereof according to the present invention compensate for a characteristic value deviation existing between sensing lines of the sensing lines with respect to a sensing value obtained by sensing driving, There is an effect to prevent.

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

14, the sensing values Vsen for compensating the sub-pixel characteristic value deviation for each subpixel have a more uniform graph than the initial sensing value Initial, but the sensing values Vsen between the source driver ICs Vsen) deviation occurs (see Update, FIG. 9).

However, as in the present invention, the compensation sensing values (C-Vsen) obtained by progressing the < link characteristic value deviation > compensation of the reference voltage line that further obtains the sensing value (Vsen) It can be seen that a deviation does not occur between the electrodes (the present invention)

That is, in the present invention, the sensing drive for compensating for the normal < subpixel characteristic value deviation > is performed, but the sensing value Vsen is changed due to the < link characteristic value deviation of the sensing line (reference voltage line) So as to prevent the deviation of the sensing value (Vsen) from being generated.

When data is compensated based on the sensed value (C-Vsen), i.e., the compensated sensing value (C-Vsen), and the image is displayed on the display panel, due to the conventional sensing value (Vsen) It is possible to eliminate the image quality defect that has occurred.

FIG. 15 is a flowchart illustrating a method of compensating an OLED display in consideration of sub-pixel feature value deviation compensation and link characteristic value deviation according to the present invention.

Referring to FIG. 15, in the sensing driving method of the OLED display 100 according to the present invention, sensing driving for compensating for sub-pixel characteristic value deviation is performed for each of the subpixels to be sensed (S1501) . The sensing for compensating the sub-pixel characteristic value deviation is performed according to the description of FIG. 3 and FIG.

As described above, when the sensing drive for compensating the sub-pixel characteristic value deviation is performed, the characteristic value for each sub-pixel, that is, the threshold voltage (Vth) sensing value Vsen is obtained from the reference voltage line (S1502).

Then, by using the compensation unit having the components shown in FIG. 10, the link characteristic value information existing in the sensing value Vsen and the reference voltage line (sensing line) is calculated, The link characteristic value deviation> compensation is advanced (S1503).

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

According to the sensing driving method of the present invention, the sensing for compensating the sub-pixel characteristic value difference is performed for each sub-pixel, and the compensation of the link characteristic value is performed for the sensing value (Vsen) (Vsen) can be compensated.

As described above, when the sensing value Vsen is compensated for and the compensation sensing value C-Vsen is obtained, data compensation is performed based on the sensing value Vsen so that the data compensation by the sensing value Vsen, A higher quality image can be realized.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the appended claims. , Separation, substitution, and alteration of the invention will be apparent to those skilled in the art. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: organic light emitting display
110: Display panel
120: Data driver
130: gate driver
140: Timing controller
300:
320:
321; Lookup table
322: Sensing value storage unit
323:
324: compensation value generating unit

Claims (10)

A display panel in which a plurality of data lines and a plurality of gate lines are arranged and a plurality of subpixels are arranged in a matrix type;
A data driver for driving the plurality of data lines;
A gate driver for driving the plurality of gate lines; And
And a controller for controlling the data driver and the gate driver,
Each of the sub-
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 the data voltage; A sensing transistor electrically connected between the reference voltage lines; and a storage capacitor electrically connected between the first node and the second node of the driving transistor,
A compensator for obtaining a sensing value through a sensing line to compensate for a characteristic value deviation of driving transistors arranged in each subpixel and obtaining a compensation sensing value by taking into consideration a characteristic value deviation of the sensing line with respect to the sensing value obtained; And an organic light emitting diode (OLED). The method according to claim 1,
Wherein the compensation unit comprises:
A lookup table for storing characteristic value information of each sensing line,
A sensing value storing unit for storing the sensing value,
A calculation unit for calculating characteristic value information of the sensing line corresponding to the sensing value and the sensing value,
And a compensation value generation unit for generating a compensation sensing value using the value calculated by the calculation unit. The method according to claim 1,
Wherein the sensing line is a reference voltage line. The method according to claim 1,
Wherein the characteristic value of the sensing line is any one of a capacitance, a resistance, and an impedance of a sensing link line of the sensing line integrally disposed in a non-display region of the display panel. 5. The method of claim 4,
Wherein the sensing link line of the sensing line is a reference voltage link line of the reference voltage line. The method according to claim 1,
Wherein a characteristic value of the driving transistor is a threshold voltage or a mobility. A switching transistor electrically connected between a first node of the driving transistor and a data line supplying a data voltage; and a second node of the driving transistor, A display panel having a plurality of subpixels including a sensing transistor electrically connected between the voltage lines and a storage capacitor electrically connected between the first node and the second node of the driving transistor; A method of driving an organic light emitting display including a data driver for outputting a voltage and a controller for controlling the data driver,
Performing sensing for compensating a characteristic value deviation of each subpixel;
The sensing is performed to obtain a sensing value for each subpixel;
Acquiring a compensation sensing value by calculating the sensing value of the sensing line and the link line characteristic value information of the sensing line;
And compensating the data using the compensation sensing value. 8. The method of claim 7,
Wherein the characteristic value of the sensing line is any one of a capacitance, a resistance, and an 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,
Wherein characteristic-value deviation compensation of each sub-pixel is characteristic-value deviation compensation of a driving transistor disposed in each sub-pixel. 10. The method of claim 9,
Wherein a characteristic value of the driving transistor is a threshold voltage or a mobility.

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