KR20170080330A - Organic light emitting diode display and driving circuit thereof - Google Patents

Abstract

The present invention provides a display device for supplying a data voltage by compensating for a voltage variation of a reference voltage line. Specifically, such a display device includes a panel, a gate driver, a storage, and a data driver. A first pixel and a second pixel sharing the reference voltage line are disposed on the panel. The gate driver supplies the turn-on voltage to the sensing transistors of the first and second pixels connected to the reference voltage line in the N (N is a natural number) horizontal period. The storage unit stores the voltage variation of the reference voltage line due to the turn-on of the second pixel sensing transistor. Then, the data driver supplies the data voltage compensated in accordance with the voltage variation amount to the first pixel in the Nth horizontal period.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode (OLED) display device and a driving circuit for the OLED display device.

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

BACKGROUND ART [0002] As an information-oriented society develops, there have been various demands for apparatuses for displaying images. Recently, a liquid crystal display device, a plasma display panel, an organic light- Various display devices such as an image display device and an image display device are used as devices for displaying images.

Of these various display devices, organic light emitting display devices have advantages of high response speed, high luminous efficiency, luminance and viewing angle by using an organic light emitting diode (OLED) which emits light by themselves, .

The OLED display includes an organic light emitting diode (OLED), a driving transistor (DRT), a switching transistor (SWT), and a sensing transistor (SENT).

The source node of the driving transistor DRT located in each pixel is electrically connected to the anode electrode of the organic light emitting diode OLED. The gate node of the driving transistor DRT is electrically connected to the source node or the drain node of the switching transistor SWT. The drain node of the driving transistor DRT is electrically connected to a driving voltage line (DVL) for supplying a driving voltage.

The switching transistor SWT is located between the gate node of the driving transistor DRT and the data line. The switching transistor SWT is turned on by the scan signal SCAN to transfer the data voltage supplied to the data line to the gate node of the driving transistor DRT.

The sensing transistor SENT is located between the source node of the driving transistor DRT and the reference voltage line. The sensing transistor SENT is turned on by the sensing signal SENSE to transmit the reference voltage supplied to the reference voltage line to the source node of the driving transistor DRT.

When the data voltage is formed at the gate node of the driving transistor DRT by turning on the switching transistor SWT in this pixel structure and the reference voltage is formed at the source node of the driving transistor DRT by turning on the sensing transistor SENT , A gate-source voltage is formed in the driving transistor DRT with the magnitude of the data voltage-reference voltage. The luminance of the organic light emitting diode OLED is determined by the gate-source voltage magnitude of this driving transistor DRT.

Meanwhile, the organic light emitting diode (OLED) includes an anode electrode, an organic layer, and a cathode electrode, and a short circuit may occur between the anode electrode and the cathode electrode due to a foreign substance or defect. In such a case, a defect such as a dark spot may be visually recognized in a pixel where a short circuit occurs. Then, the voltage (reference voltage) of the reference voltage line connected to the pixel can be lowered.

The anode of the organic light emitting diode OLED is connected to the reference voltage line through the sensing transistor SENT. When the organic light emitting diode OLED is short-circuited, the voltage of the reference voltage line connected to the shorted organic light emitting diode OLED Reference voltage) falls. The falling of the voltage (reference voltage) of this reference voltage line may cause defects of other pixels.

Unlike the data voltage, the reference voltage need not have a different size for each pixel, so that two or more pixels in the organic light emitting display can receive the same reference voltage simultaneously through one reference voltage line. However, in the reference voltage sharing structure, when the organic light emitting diode OLED of a specific pixel is short-circuited, the voltage (reference voltage) of the reference voltage line is lowered to the shorted organic light emitting diode OLED, The reference voltages of other shared pixels can also be lowered.

When the reference voltage falls, when the same data voltage is supplied, the gate-source voltage of the driving transistor DRT becomes relatively larger. The higher the gate-source voltage, the higher the luminance, and the unintended increase in luminance can be seen as a failure to the user.

In view of the foregoing, it is an object of the present invention to provide a technique for compensating for the influence of a reference voltage fluctuated in accordance with a defect of a specific pixel on another pixel when a plurality of pixels share a reference voltage.

In order to achieve the above object, in one aspect, the present invention provides a display device for supplying a data voltage by compensating for a voltage variation amount of a reference voltage line. Specifically, such a display device includes a panel, a gate driver, a storage, and a data driver. A first pixel and a second pixel sharing the reference voltage line are disposed on the panel. The gate driver supplies the turn-on voltage to the sensing transistors of the first and second pixels connected to the reference voltage line in the N (N is a natural number) horizontal period. The storage unit stores the voltage variation of the reference voltage line due to the turn-on of the second pixel sensing transistor. Then, the data driver supplies the data voltage compensated in accordance with the voltage variation amount to the first pixel in the Nth horizontal period.

In another aspect, the present invention provides a driving circuit for compensating a data voltage of a first pixel and a second pixel sharing a reference voltage line. Such a drive circuit includes a storage unit and a data driver. The storage unit stores a voltage variation amount of the reference voltage line in accordance with the connection of the second pixel and the reference voltage line, and the data driver decreases the voltage variation amount in the horizontal period in which the first pixel and the second pixel are simultaneously connected to the reference voltage line. And supplies the data voltage to the first pixel.

As described above, according to the present invention, when a plurality of pixels share a reference voltage, it is possible to compensate for the influence of a reference voltage which varies according to a defect of a specific pixel on other pixels.

1 is a schematic system configuration diagram of a display apparatus according to an embodiment.
2 is a diagram showing two pixels sharing a reference voltage.
FIG. 3 is a view showing waveforms of a scan signal and a sensing signal supplied to the pixels of FIG. 2. FIG.
4 is a diagram showing that a defect occurs in one of the pixels sharing the reference voltage.
5 is a view showing waveforms of a scan signal, a sensing signal, and a reference voltage supplied to the pixels of FIG.
6 is a simplified flowchart of a method of compensating an organic light emitting display according to an embodiment.
7 is a view showing a voltage formed on an anode electrode of an organic light emitting diode when a test current is supplied to a normal pixel.
8 is a diagram showing a voltage formed on an anode electrode of an organic light emitting diode when a test current is supplied to a defective pixel.
9 is a diagram showing voltages formed on the anode electrodes of defective pixels when the data driver supplies data voltages to defective pixels.
10 is a flowchart illustrating a method of calculating a voltage variation amount of an OLED display according to an exemplary embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected." In the same context, when an element is described as being formed on an "upper" or "lower" side of another element, the element may be formed either directly or indirectly through another element As will be understood by those skilled in the art.

1 is a schematic system configuration diagram of a display apparatus according to an embodiment.

1, the OLED display 100 may include a panel 110, a gate driver 120, a data driver 130, a timing controller 140, and a storage unit 150.

A plurality of data lines DL, a plurality of gate lines GL and a plurality of reference voltage lines RVL are arranged on the panel 110, Pixel) may be disposed.

The gate driver 120 may supply a turn-on voltage or a turn-off voltage to the gate line GL in accordance with a control signal of the timing controller 140. [ The gate line GL may be composed of a switching gate line GLa and a sensing gate line GLb.

The gate driver 120 may control the connection between the data line DL and each pixel SP by inputting a scan signal to the switching gate line GLa. The gate driver 120 may control the connection between the reference voltage line RVL and each pixel SP by inputting a sensing signal to the sensing gate line GLb.

The data driver 130 may convert the image data received from the timing controller 140 into an analog data voltage and supply the data voltage to the data line DL.

The data driver 130 may supply the reference voltage to each pixel SP through the reference voltage line RVL. The data voltage supplied through the data line DL to which a driving transistor DRT (to be described later) is arranged with reference to FIG. 2 and the reference voltage supplied through the reference voltage line RVL The gate-source voltage of the driving transistor can be formed.

The data driver 130 can sense the characteristic value or the characteristic variation amount of each pixel SP through the reference voltage line RVL. The reference voltage line RVL may be referred to as a sensing line (SL) in terms of sensing the characteristic value of each pixel SP. The data driver 130 may further include an ADC (Analog Digital Converter) connected to the reference voltage line RVL to sense the characteristic value of each pixel SP. The data driver 130 may further include a switch arrangement and supply a reference voltage to the reference voltage line RVL according to the timing control or sense the characteristic value of the pixel SP through the ADC.

The timing controller 140 may supply various control signals to the gate driver 120 and the data driver 130. The timing controller 140 may convert image data received from a host (not shown) into a format suitable for the data driver 130, and then transmit the image data to the data driver 130.

The storage unit 150 may store information necessary for compensating the data voltage. The timing controller 140 may compensate the image data using the information stored in the storage unit 150 and transmit the compensated image data to the data driver 130. [

Meanwhile, the plurality of pixels SP disposed in the panel 110 may share a reference voltage.

As described above, the data voltage and the reference voltage can form the gate-source voltage of the driving transistor DRT located in each pixel SP. The gate-source voltage of the driving transistor DRT determines the driving current of the driving transistor DRT and this driving current can determine the luminance of the organic light emitting diode OLED.

The data driver 130 controls the brightness of each pixel SP by controlling the gate-source voltage of the driving transistor DRT. Generally, the data driver 130 controls the data voltage supplied to the data line DL, The gate-source voltage of the transistor Q3 is controlled.

The reference voltage can be fixed to a constant value because the data voltage fluctuates for the luminance control. The data driver 130 may determine the data voltage to be a value relative to the reference voltage under the assumption that the reference voltage is fixed.

When the reference voltage is fixed, the plurality of pixels SP can share the reference voltage. The plurality of pixels SP can receive the same reference voltage at the same time.

A series of pixels SP arranged in a direction X parallel to the gate line GL can share a reference voltage. For example, when red (R), green (G), blue (B) and white (W) pixels are arranged in the gate line direction (X) , The blue (B) pixel, and the white (W) pixel may share a reference voltage.

As another example, a series of pixels SP arranged in the direction crossing the gate line GL or in the direction Y parallel to the reference voltage line RVL may share the reference voltage.

2 is a diagram showing two pixels sharing a reference voltage.

Referring to FIG. 2, the first pixel SP1 and the second pixel SP2, which are arranged in a direction Y parallel to the reference voltage line RVL, share the same reference voltage line RVL.

Each pixel SP includes an organic light emitting diode (OLED), a driving transistor (DRT) driving the organic light emitting diode (OLED), a driving transistor A switching transistor SWT for transferring the data voltage to the gate node N2 of the driving transistor DRT, a storage capacitor Cstg for maintaining the data voltage for one frame time, And a sensing transistor SENT (Sense Transistor) for transmitting the reference voltage Vref to the source node N1.

The organic light emitting diode OLED may include 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).

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

The source node N1 of the driving transistor DRT may be electrically connected to the first electrode of the organic light emitting diode OLED. The gate node N2 of the driving transistor DRT may be electrically connected to the source node or the drain node of the switching transistor SWT. The drain node N3 of the driving transistor DRT may be electrically connected to a driving voltage line DVL that supplies the driving voltage EVDD.

The driving transistor DRT and the switching transistor SWT may be either N-type or P-type as in the example of FIG.

The switching transistor SWT is located between the data line DL and the gate node N2 of the driving transistor DRT and can be controlled by receiving the scan signal SCAN through the switching gate line GLa.

The switching transistor SWT is turned on by the scan signal SCAN to connect the data line DL to the gate node N2 of the driving transistor DRT. The switching transistor SWT may transfer the data voltage Vdata supplied to the data line DL to the gate node N2 of the driving transistor DRT.

The storage capacitor Cstg is located between the source node N1 and the gate node N2 of the driving transistor DRT.

The storage capacitor Cstg may be a parasitic capacitor (e.g., Cgs, Cgd) that is an internal capacitor existing between the source node N1 and the gate node N2 of the driving transistor DRT, And may be an external capacitor that is intentionally designed outside the transistor DRT.

The sensing transistor SENT is located between the reference voltage line RVL and the source node N1 of the driving transistor DRT and can be controlled by receiving the sensing signal SENSE through the sensing gate line GLb.

The sensing transistor SENT is turned on by the sensing signal SENSE to connect the reference voltage line RVL to the source node of the driving transistor DRT. The sensing transistor SENT may transmit the reference voltage Vref supplied to the reference voltage line RVL to the source node N1 of the driving transistor DRT.

The switching transistor SWT is turned on so that the data voltage Vdata is supplied to the gate node N2 of the driving transistor DRT and the sensing transistor SENT is turned on to supply the reference voltage Vcc to the source node N1 of the driving transistor DRT. (Vref) is supplied, a voltage corresponding to the data voltage-reference voltage (Vdata-Vref) is formed as the gate-source voltage of the driving transistor DRT.

FIG. 3 is a view showing waveforms of a scan signal and a sensing signal supplied to the pixels of FIG. 2. FIG.

Referring to FIGS. 2 and 3, the scan signal SCAN supplies a turn-on voltage for one horizontal period 1H and the sense signal SENSE supplies a turn-on voltage during two horizontal periods 2H.

A parasitic capacitor Cp is formed in parallel in the organic light emitting diode OLED located in each pixel SP. The reference voltage Vref supplied to the source node N1 of the driving transistor DRT can maintain a stable state after all of these parasitic capacitors Cp are charged. Since the source node voltage of the driving transistor DRT reaches such a stable state, the gate driving unit can supply the sensing signal SENSE during which the turn-on voltage is formed during the two horizontal periods 2H, because it may take a certain time. Such driving is also referred to as 2H driving.

On the other hand, the first pixel SP1 is supplied with the turn-on voltage as the scan signal SCAN (n) in the N (N is a natural number) horizontal period, the second pixel SP2 is supplied with the scan signal (SCAN (n + 1)). On the side of the gate driver, the gate driver supplies the turn-on voltage to the switching transistor SWT of the first pixel SP1 in the Nth horizontal period, and the turn-on voltage of the second pixel SP2 And supplies a turn-on voltage to the switching transistor SWT.

The turn-on voltage of the sensing signal SENSE may be supplied one horizontal period earlier than the turn-on voltage of the scan signal SCAN. Accordingly, the first pixel SP1 may be supplied with the sensing signal SENSE in the N- And a turn-on voltage is supplied to the signal SENSE (n). The second pixel SP2 may be supplied with the turn-on voltage as the sensing signal SENSE (n + 1) in the Nth horizontal period and the N + 1th horizontal period.

From the side of the gate driver, the gate driver supplies the turn-on voltage to the sensing transistor SENT of the first pixel SP1 in the (N-1) th horizontal period and the Nth horizontal period. The gate driver supplies the turn-on voltage to the sensing transistor SENT of the second pixel SP2 in the Nth horizontal period and the (N + 1) th horizontal period.

Since the sensing signal SENSE supplies the turn-on voltage during the two horizontal periods 2H, the first pixel SP1 and the second pixel SP2, to which the turn-on voltage of the scan signal SCAN is continuously supplied, (RVL) during the Nth horizontal period in FIG. 3).

On the other hand, when two or more pixels are connected to one reference voltage line RVL at the same time, if a short circuit occurs in one of the two or more pixels, the voltage of the reference voltage line RVL falls, The voltage drop of the line RVL may be affected.

4 is a diagram showing that a defect occurs in one of the pixels sharing the reference voltage.

Referring to FIG. 4, a failure occurs in the organic light emitting diode OLED of the second pixel SP2 due to a short circuit.

The organic light emitting diode OLED may include an anode electrode, an organic layer, and a cathode electrode, and a short circuit may occur between the anode electrode and the cathode electrode.

In general, when the organic light emitting diode OLED does not emit light, the organic light emitting diode OLED may be regarded as a capacitor. The parasitic capacitor Cp is formed in parallel in the organic light emitting diode OLED. When the organic light emitting diode OLED does not emit light, only such a parasitic capacitor Cp can be seen. On the other hand, if a short circuit occurs in the organic light emitting diode OLED, the organic light emitting diode OLED can be regarded as a resistor Rs.

The anode electrode of the organic light emitting diode OLED is connected to the reference voltage line RVL according to the sensing signal SENSE and the reference voltage Vref is transmitted to the anode electrode of the organic light emitting diode OLED. At this time, when the organic light emitting diode OLED is viewed as the capacitor Cp, the current supplied from the reference voltage line RVL charges the capacitor Cp. After the charging is completed, the voltage of the capacitor Cp becomes the reference voltage Vref.

On the other hand, when the organic light emitting diode OLED is regarded as the resistor Rs due to the short circuit of the organic light emitting diode OLED, a voltage lower than the reference voltage Vref is formed at the anode electrode of the organic light emitting diode OLED. The reference voltage line RVL has a line resistance. The line resistance and the resistance of the organic light emitting diode OLED act like a voltage divider so that the anode electrode of the organic light emitting diode OLED and the reference voltage line RVL are supplied with a reference voltage A voltage lower than Vref is formed.

The reference voltage Vref lowered by the short circuit of the organic light emitting diode OLED may affect other pixels sharing the reference voltage Vref.

5 is a view showing waveforms of a scan signal, a sensing signal, and a reference voltage supplied to the pixels of FIG.

Referring to FIGS. 4 and 5, since a short circuit occurs in the organic light emitting diode OLED located in the second pixel SP2, the reference voltage line RVL is connected to the second pixel SP2, And the (N + 1) th horizontal period, the reference voltage Vref is lowered.

The first pixel SP1 and the second pixel SP2 are simultaneously driven in 2H so that the first pixel SP1 and the second pixel SP2 are simultaneously applied to the reference voltage line RVL in the Nth horizontal period, And receives the same reference voltage Vref. Accordingly, the falling of the reference voltage Vref in the Nth horizontal period also affects the first pixel SP1.

The current driving the organic light emitting diode OLED is determined by the gate-source voltage of the driving transistor DRT, and the gate-source voltage is determined by the difference between the data voltage Vdata and the reference voltage Vref. However, when the reference voltage Vref is lowered, the gate-source voltage is increased, so that the driving current supplied to the organic light emitting diode OLED also increases.

The organic light emitting diode display 100 according to an exemplary embodiment of the present invention can reduce the variation of the reference voltage Vref in order to eliminate the influence of the drop of the reference voltage Vref due to the failure of the second pixel SP2 on the first pixel SP1, And compensates the data voltage for the first pixel SP1 by the voltage difference DELTA Vr and outputs the compensated data voltage.

6 is a simplified flowchart of a method of compensating an organic light emitting display according to an embodiment.

6, when the organic light emitting diode display 100 (for example, the timing controller 140) compensates the image data for the first pixel SP1, the first pixel SP1 is a defective pixel - And determines whether the second pixel SP2 is simultaneously connected to the reference voltage line RVL in a specific horizontal period (S602).

When it is determined that the first pixel SP1 is connected to the reference voltage line RVL simultaneously with the defective pixel in a specific horizontal period at the same time (Yes in S602), the organic light emitting diode display 100 determines that The data voltage is compensated (S604).

At this time, the organic light emitting diode display 100 stores the voltage variation amount? Vr of the reference voltage Vref due to the defective pixel, and the data voltage Vref for the first pixel SP1 according to the voltage variation amount? (Vdata) can be compensated.

In particular, when the timing controller 140 performs the compensation function in the OLED display 100, the timing controller 140 compensates the image data of the first pixel SP1 according to the voltage variation amount? Vr And may transmit the compensated image data to the data driver 130. [ The data driver 130 may convert the compensated image data into a data voltage and output the data voltage.

On the other hand, the organic light emitting diode display 100 can store the voltage fluctuation amount DELTA Vr of the reference voltage Vref by the defective pixel in the storage unit 150 and the like. The voltage fluctuation amount DELTA Vr may be a predetermined value during the manufacturing process or may be a value calculated or measured during operation of the organic light emitting display 100. [

Hereinafter, an embodiment for calculating the voltage fluctuation amount DELTA Vr during the operation of the organic light emitting display device 100 will be described with reference to Figs. 7 to 10. Fig.

The organic light emitting display 100, for example, the data driver 130 may supply a test current to each pixel SP and measure a voltage across the organic light emitting diode OLED according to a test current. Alternatively, the organic light emitting diode display 100 may supply the test current to each pixel SP and measure the source node voltage of the driving transistor DRT according to the test current. Then, the organic light emitting diode display 100 calculates the voltage fluctuation amount DELTA Vr of the reference voltage line RVL using the measured voltage - for example, the voltage across the organic light emitting diode or the source node voltage of the driving transistor - .

FIG. 7 is a view showing a voltage formed on an anode electrode of an organic light emitting diode when a test current is supplied to a normal pixel, and FIG. 8 is a view showing a voltage formed on an anode electrode of the organic light emitting diode when a test current is supplied to a defective pixel. to be.

The OLED display 100, for example, the data driver 130, may supply a test current Id to each pixel SP. The test current Id may be, for example, a constant current.

The organic light emitting diode display 100 may supply the test current Id to the anode electrode of the organic light emitting diode OLED through the driving transistor DRT. At this time, the driving transistor DRT and the organic light emitting diode OLED may be connected in series. In this structure, the test current Id supplied to the driving transistor DRT is transmitted to the anode electrode of the organic light emitting diode OLED through the drain node N3 and the source node N1 of the driving transistor DRT .

The test current Id transferred to the anode electrode of the organic light emitting diode OLED charges the parasitic capacitor Cp connected in parallel with the organic light emitting diode OLED.

In FIG. 7, the graph on the right represents the time-to-voltage magnitude of the voltage (Vsen) supplied to the anode electrode of the organic light emitting diode (OLED) to which the test current Id is supplied.

A normal organic light emitting diode (OLED) may appear as a capacitor until a voltage higher than the threshold voltage is supplied to the anode electrode, and a voltage Vsen formed in the anode electrode may be increased to a constant value as shown in FIG. 7 .

Meanwhile, the pixel shown in FIG. 8 is a pixel in which the anode electrode and the cathode electrode of the organic light emitting diode OLED are short-circuited. When the organic light emitting diode OLED is short-circuited, the organic light emitting diode OLED may be regarded as a resistor Rs.

The organic light emitting diode display 100 may supply the test current Id to the anode electrode of the organic light emitting diode OLED through the driving transistor DRT with respect to the defective pixel.

At this time, the organic light emitting diode OLED appears as a resistor Rs according to a short circuit of the organic light emitting diode OLED, and a voltage Vsen formed on the anode electrode of the organic light emitting diode OLED is divided into a test current Id The resistance Rs of the organic light emitting diode OLED is saturated.

Referring to FIGS. 7 and 8, the organic light emitting diode display 100 is formed at an anode electrode of the organic light emitting diode OLED at a certain time point T1 after supplying a test current Id to the driving transistor DRT. The source node voltage of the driving transistor DRT may be observed on the other side of the voltage Vsen to determine whether the pixel SP is a normal pixel or a defective pixel.

In addition, the organic light emitting diode display 100 (for example, the timing controller 140) may use the test current Id and the anode electrode voltage Vsen - or the source node voltage - to calculate the voltage variation of the reference voltage line RVL (? Vr) can be calculated. For example, the organic light emitting diode display 100 may calculate the short circuit resistance Rs of the pixel SP of the organic light emitting diode OLED by dividing the source node voltage Vsen by the test current Id. The organic light emitting diode display 100 can calculate the voltage variation amount? Vr of the reference voltage line RVL according to the shorting resistor Rs.

9 is a diagram showing voltages formed on the anode electrodes of defective pixels when the data driver supplies data voltages to defective pixels.

9, defects are generated in the pixels SP located at the coordinates (X1, Y1) with respect to the direction Y parallel to the direction X intersecting the reference voltage line RVL, Is shown as a resistance Rs.

The data driver 130 supplies the reference voltage Vref through the reference voltage line RV. At this time, since the pixel SP is viewed as the shorting resistor Rs, A voltage corresponding to the voltage division of the series resistance is formed at the anode electrode of the transistor.

Specifically, the voltage Vsen formed on the anode electrode of the organic light emitting diode can be determined according to the following equation.

[Equation 1]

Vsen = Vref x Rs / (Rs + Rln)

In Equation 1, Rln is the line resistance of the reference voltage line RVL.

The reference voltage line RVL is disposed across the non-display area NA and the display area AA of the panel 110. At this time, the line resistance Rln of the reference voltage line RVL is non- (Rlink) located in the display area AA and a part located in the display area AA. The portion of the line resistance Rln located in the display area AA can be calculated by multiplying the line resistance r_ref of the pixel size unit by the Y direction coordinate of the pixel in FIG. 9 by Y1-.

&Quot; (2) "

Vsen = Vref x Rs / (Rs + Rln) = Vref x Rs / (Rs + Rlink + Y1 x r_ref)

The organic light emitting diode display 100, for example, the timing controller 140 may calculate a source voltage Vsen of a driving transistor or a voltage Vsen formed on the anode electrode of the organic light emitting diode according to Equation (2).

Specifically, the organic light emitting diode display 100 may calculate and store the short circuit resistance Rs of the defective pixel by the method described with reference to FIG. The organic light emitting diode display 100 displays the magnitude of the reference voltage Vref supplied to the reference voltage line RVL, the line resistance Rlink of the reference voltage line RVL in the non-display area NA, The line resistance r_ref of the pixel size unit in the display area AA of the voltage line RVL can be stored in advance.

The organic light emitting diode display 100 uses the pre-stored values and the first direction (Y direction) coordinates of the defective pixel to calculate the voltage Vsen formed on the anode electrode of the organic light emitting diode or the source The node voltage can be calculated.

When the source node voltage of the driving transistor is calculated, the OLED display 100 can calculate the voltage variation (DELTA Vr) of the reference voltage line RVL using this source node voltage.

&Quot; (3) "

Vr = Vref - Vsen

10 is a flowchart illustrating a method of calculating a voltage variation amount of an OLED display according to an exemplary embodiment of the present invention.

10, the organic light emitting diode display 100 (for example, the data driver 130) outputs a test current Id to each pixel SP (S1002), and the organic light emitting diode The voltage formed at the anode electrode or the voltage Vsen formed at the source node of the driving transistor can be measured (S1004).

Then, the OLED display 100 (e.g., the timing controller 140) can determine whether the pixel is defective based on the measured voltage Vsen (S1006). For example, when the voltage Vsen measured at a specific point in time is lower than a predetermined set voltage, the OLED display 100 may determine that the pixel is defective.

The organic light emitting diode display 100 calculates the short circuit resistance Rs of the pixel in accordance with the measured voltage Vsen and the test current Id, The voltage variation amount DELTA Vr of the reference voltage line RVL can be calculated (S1008).

The organic light emitting diode display 100 may store the coordinates of the defective pixel and the voltage variation amount DELTA Vr due to the defective pixel (S1010). At this time, the coordinates of the defective pixel and the voltage variation amount? Vr can be stored in the storage unit 150 in the form of a look-up table.

As described with reference to FIGS. 7 to 10, the organic light emitting diode display 100 can calculate the voltage variation amount? Vr of the reference voltage line RVL caused by the defective pixel. The OLED display 100 can compensate the data voltage or image data of the pixels sharing the reference voltage with the defective pixel by using the voltage variation amount? Vr.

For example, the organic light emitting diode display 100 may compensate the data voltage of the other pixel by decreasing the data voltage by the voltage variation amount? Vr of the reference voltage. Specifically, when the first pixel and the second pixel are simultaneously connected to the reference voltage line (RVL) in the Nth horizontal period and the second pixel has a defect due to a short circuit, the organic light emitting diode display (100) The voltage variation amount DELTA Vr of the reference voltage line RVL can be calculated in advance and the data voltage for the first pixel can be compensated for by the voltage variation amount DELTA Vr. Alternatively, the organic light emitting diode display 100 may compensate the image data so that the data voltage for the first pixel is compensated for by the voltage variation amount? Vr.

The magnitude of the driving current supplied to the organic light emitting diode is determined by the difference between the gate voltage and the source voltage of the driving transistor. At this time, a data voltage is supplied to the gate node of the driving transistor, and a reference voltage is transmitted to the source node. In this structure, when the reference voltage fluctuates due to a defect of a specific pixel as described above, the organic light emitting display according to the embodiment compensates the data voltage by the variation of the reference voltage, so that the gate- To maintain a constant value.

According to this embodiment, it is possible to compensate the influence of the reference voltage fluctuated according to the defects of the specific pixel on other pixels.

It is to be understood that the terms "comprises", "comprising", or "having" as used in the foregoing description mean that the constituent element can be implanted unless specifically stated to the contrary, But should be construed as further including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. 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.

Claims (11)

A panel in which a first pixel and a second pixel sharing a reference voltage line are disposed;
A gate driver for supplying a turn-on voltage to the sensing transistor of the first pixel and the second pixel connected to the reference voltage line in N (N is a natural number) horizontal period;
A storage unit for storing a voltage variation of the reference voltage line due to the turn-on of the second pixel sensing transistor; And
A data driver for supplying a data voltage compensated for the voltage variation to the first pixel in the Nth horizontal period,
. The method according to claim 1,
Wherein the gate driver comprises:
On voltage is supplied to the sensing transistors of the first pixel and the second pixel in the Nth horizontal period and the (N + 1) th horizontal period,
In the Nth horizontal period, a turn-on voltage is supplied to the switching transistor of the first pixel connected to the first data line,
And supplies a turn-on voltage to the switching transistor of the second pixel connected to the second data line in the (N + 1) -th horizontal period. The method according to claim 1,
Wherein each of the first pixel and the second pixel includes:
A driving transistor, a sensing transistor for connecting the source node of the driving transistor and the reference voltage line, a switching transistor for connecting a gate node of the driving transistor to a data line, and an organic light emitting diode connected to a source node of the driving transistor / RTI > The method of claim 3,
Wherein the second pixel comprises:
A display device comprising an organic light emitting diode in which an anode electrode and a cathode electrode are short-circuited. The method of claim 3,
And a timing controller for transmitting the compensated image data to the data driver in accordance with the amount of voltage variation,
The data driver may include:
And converting the compensated image data to generate the compensated data voltage. 6. The method of claim 5,
The data driver may include:
The method comprising: supplying a test current to the driving transistor of the first pixel and the second pixel, measuring a source node voltage of each driving transistor,
The timing controller includes:
And calculates a voltage variation amount of the reference voltage line using the test current and the source node voltage. The method according to claim 6,
The timing controller includes:
Dividing the source node voltage of the second pixel by the test current to calculate a short circuit resistance of the second pixel with respect to the organic light emitting diode, and calculating a voltage variation of the reference voltage line according to the short circuit resistance. 8. The method of claim 7,
The timing controller includes:
Wherein Rs is a short-circuit resistance, Rlink is a line resistance of a portion located in a non-display region of the reference voltage line, and r_ref Is a line resistance in a pixel size unit of a portion located in the display region of the reference voltage line, and Y is a first direction coordinate of the second pixel.
? Vr = Vref x (Rlink + Yxr_ref) / (Rs + Rlink + Yxr_ref) A driving circuit for compensating a data voltage of a first pixel and a second pixel sharing a reference voltage line,
A storage unit for storing a voltage variation amount of the reference voltage line according to a connection between the second pixel and the reference voltage line; And
A data driver for supplying a data voltage reduced by the voltage variation amount to the first pixel in a horizontal period in which the first pixel and the second pixel are simultaneously connected to the reference voltage line,
. 10. The method of claim 9,
And a timing controller for compensating the image data for the first pixel according to the voltage variation amount and transmitting the compensated image data to the data driver. 11. The method of claim 10,
Wherein each of the first pixel and the second pixel includes:
A driving transistor, a sensing transistor for connecting the source node of the driving transistor and the reference voltage line, a switching transistor for connecting a gate node of the driving transistor to a data line, and an organic light emitting diode connected to a source node of the driving transistor and,
The data driver may include:
A source driver circuit for supplying a test current to the driving transistors of the first pixel and the second pixel and measuring a source node voltage of each driving transistor,
The timing controller includes:
And calculates a voltage variation amount of the reference voltage line using the test current and the source node voltage.

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