KR102484869B1 - Organic light emitting display device and method for driving organic light emitting display device - Google Patents

Abstract

The present embodiments relate to an organic light emitting display device and a driving method of the organic light emitting display device, and a reference voltage output from a data driver is transferred from a timing controller to a data driver at the timing of transition from a blank period in which no image data voltage is output to an active period. By comparing the voltage output with the voltage output and adjusting the data voltage level of some sections of the blank section according to the comparison result, the ripple of the reference voltage occurring at the timing of transition from the blank section to the active section is improved and due to the ripple of the reference voltage It is possible to improve a horizontal band defect at an upper portion of an organic light emitting display panel.

Description

Organic light emitting display device and method of driving the organic light emitting display device

The present embodiments relate to an organic light emitting display device and a method of driving the organic light emitting display device.

An organic light emitting display device that has recently been in the limelight as a display device uses organic light emitting diodes (OLEDs) that emit light by itself, and thus has advantages of fast response speed, high contrast ratio, luminous efficiency, luminance, and viewing angle.

Such an organic light emitting display device includes an organic light emitting display panel including subpixels in which a plurality of gate lines and a plurality of data lines are disposed and disposed in an area where the gate lines and data lines intersect, and a gate driving the plurality of gate lines. It includes a driver, a data driver for supplying data voltages to a plurality of data lines, a timing controller for controlling driving of the gate driver and the data driver, and the like. It includes a driving transistor for driving.

The data driver not only supplies data voltages to a plurality of data lines disposed on the organic light emitting display panel, but also to a plurality of voltage lines disposed on the organic light emitting display panel, such as a driving voltage line and a reference voltage line, corresponding to each voltage line. supply voltage to

At this time, the timing controller outputs a reference voltage to the data driver for the voltage output by the data driver to each voltage line, and the data driver supplies voltage to each voltage line based on the voltage output by the timing controller. do.

However, when a ripple occurs in the voltage supplied by the data driver to the driving voltage line or the reference voltage line, it affects the current flowing in the organic light emitting diode (OLED) disposed in the subpixel to A gray scale according to a data voltage may not be accurately expressed.

For example, in order to compensate for a change in a characteristic value due to degradation of a driving transistor disposed in a subpixel, mobility of a driving transistor is measured in a blank period in which an image data voltage is not output.

In this case, the voltage applied to the driving transistor may be reduced by the ripple voltage of the reference voltage line for sensing the mobility of the driving transistor when the image data voltage is output after the blank period. This leads to a decrease in current flowing through the organic light emitting diode, and accordingly, a horizontal band defect occurs at an upper portion of the organic light emitting display panel.

Therefore, there is a need for a solution to the problem that a grayscale according to a data voltage supplied to a data line cannot be accurately expressed due to a ripple generated in a voltage line associated with the data line, and screen defects occur.

An object of the present embodiments is to provide an organic light emitting display device in which ripple of a voltage supplied to a voltage line disposed on an organic light emitting display panel is improved and a method for driving the organic light emitting display device.

An object of the present embodiments is to provide an organic light emitting display device and a method of driving the organic light emitting display device capable of accurately expressing a gray level according to a data voltage by improving ripple of a voltage line associated with a data line.

An object of the present embodiments is an organic light emitting display device in which ripple of a voltage generated after a period in which mobility of a driving transistor disposed in a subpixel of the organic light emitting display device is measured is improved, and driving of the organic light emitting display device. to provide a way

In one embodiment, a data driver supplies voltages corresponding to each voltage line to a plurality of voltage lines disposed on an organic light emitting display panel, and a first voltage, which is a reference voltage output from the data driver, is output by the data driver. and a timing controller that compares a second voltage output by the data driver according to the first voltage with the first voltage, and sets a data voltage level of a blank section in which no image data voltage is output according to the comparison result. can provide.

In the organic light emitting display device, the timing controller may divide the blank period into a first period and a second period and set a data voltage level of the second period according to a result of comparing the first voltage and the second voltage. If there is a difference between the voltage and the second voltage, the data voltage level of the second section may be increased and set, and if the first voltage and the second voltage are the same, the data voltage level of the second section may be maintained.

In the organic light emitting display device, the timing controller may compare the second voltage output at a point in time when the blank period is changed to a period in which the image data voltage is output, with the first voltage.

In another embodiment, the step of outputting a first voltage, which is a standard of the voltage output by the data driver, to the data driver, and comparing the second voltage output by the data driver according to the first voltage with the first voltage; A method of driving an organic light emitting display device may include setting a data voltage level of a blank section in which no image data voltage is output according to a comparison result between the first voltage and the second voltage.

In another embodiment, a voltage output unit outputs a first voltage that is a reference of a voltage output by a data driver, a comparator that compares a second voltage output by the data driver according to the first voltage with the first voltage, and a It is possible to provide a timing controller including a control unit that sets a data voltage level of a blank section in which no image data voltage is output according to a result of comparison between the first voltage and the second voltage.

According to the present embodiments, a ripple of a voltage supplied to a voltage line disposed on an organic light emitting display panel is improved so that a gray scale according to a data voltage can be accurately expressed.

According to the present embodiments, the organic light emitting display panel at the time when the image data voltage is output by improving the ripple of the voltage generated after the period of measuring the mobility of the driving transistor disposed in the subpixel of the organic light emitting display panel. It is possible to improve the transverse band defect occurring at the upper end of the

1 is a diagram showing a schematic configuration of an organic light emitting display device according to the present embodiments.
2 is a diagram showing an example of a sub-pixel structure disposed on an organic light emitting display panel according to the present embodiments.
3 and 4 are diagrams for explaining mobility measurement of a driving transistor in a subpixel according to the present embodiments.
5 is a diagram for explaining a ripple voltage generated after a period in which mobility of a driving transistor in a subpixel is measured according to the present embodiments.
6 is a diagram showing a schematic configuration of an organic light emitting display device that improves ripple voltage according to the present embodiments.
7 and 8 are diagrams for explaining an example of a method of improving a ripple voltage in an organic light emitting display device according to the present embodiments.
9 is a flowchart illustrating a process of a method of driving an organic light emitting display device according to the present exemplary embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention are described in detail below with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is or may be directly connected to that other element, but intervenes between each element. It will be understood that may be "interposed", or each component may be "connected", "coupled" or "connected" through other components.

1 shows a schematic configuration of an organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 1 , in an organic light emitting display device 100 according to the present embodiments, a plurality of gate lines GL and a plurality of data lines DL are disposed, and the gate lines GL and data lines DL An organic light emitting display panel 110 including a plurality of subpixels (SP) disposed in the crossing area, a gate driver 120 driving a plurality of gate lines (GL), and a plurality of data lines (DL). It includes a data driver 130 for supplying a data voltage, and a timing controller (T-CON, 140) for controlling the gate driver 120 and the data driver 130.

The gate driver 120 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals to the plurality of gate lines GL.

The gate driver 120 sequentially supplies scan signals of an on voltage or an off voltage to the plurality of gate lines GL under the control of the timing controller 140 to generate the plurality of gate lines GL. run sequentially.

The gate driver 120 may be located on only one side or both sides of the organic light emitting display panel 110 according to a driving method.

In addition, the gate driver 120 may include one or more gate driver integrated circuits.

Each gate driver integrated circuit is connected to a bonding pad of the organic light emitting display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method, or It can be implemented as a GIP (Gate In Panel) type and directly disposed on the organic light emitting display panel 110 . In addition, it may be integrated and disposed on the organic light emitting display panel 110, or may be implemented in a chip on film (COF) method mounted on a film connected to the organic light emitting display panel 110.

The data driver 130 drives the plurality of data lines DL by supplying data voltages to the plurality of data lines DL.

When a specific gate line GL is opened, the data driver 130 converts the image data received from the timing controller 140 into analog data voltages and supplies them to the plurality of data lines DL, thereby providing a plurality of data lines DL. ) to drive

The data driver 130 may include at least one source driver integrated circuit to drive a plurality of data lines DL.

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

In addition, each source driver integrated circuit may be implemented in a Chip On Film (COF) method. In this case, one end of each source driver integrated circuit is bonded to at least one source printed circuit board, and the other end is bonded to the organic light emitting display panel 110 .

The timing controller 140 controls the driving of the gate driver 120 and the data driver 130 by supplying various control signals to the gate driver 120 and the data driver 130 .

The timing controller 140 starts scanning according to the timing implemented in each frame, converts externally input image data according to the data signal format used by the data driver 130, and outputs the converted image data. and controls data driving at an appropriate time according to the scan.

The timing controller 140 includes various timing signals including a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input data enable (DE) signal, and a clock signal (CLK) together with input image data. are received from outside (e.g. host system).

The timing controller 140 converts the input image data input from the outside to suit the data signal format used by the data driver 130 and outputs the converted image data, as well as the gate driver 120 and the data driver 130. ), receive timing signals such as the vertical sync signal (Vsync), the horizontal sync signal (Hsync), the input data enable signal (DE), and the clock signal (CLK), and generate various control signals to generate gate drivers (120) and the data driver (130).

For example, the timing controller 140 may include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE) to control the gate driver 120 . : Gate Output Enable) and various gate control signals (GCS: Gate Control Signal) are output.

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver integrated circuits constituting the gate driver 120 . The gate shift clock (GSC) is a clock signal commonly input to one or more gate driver integrated circuits and controls shift timing of scan signals (gate pulses). The gate output enable signal GOE specifies timing information of one or more gate driver integrated circuits.

In addition, the timing controller 140, in order to control the data driver 130, a source start pulse (SSP: Source Start Pulse), a source sampling clock (SSC: Source Sampling Clock), a source output enable signal (SOE: Source It outputs various data control signals (DCS: Data Control Signal) including Output Enable) and the like.

Here, the source start pulse SSP controls data sampling start timing of one or more source driver integrated circuits constituting the data driver 130 . The source sampling clock (SSC) is a clock signal that controls sampling timing of data in each source driver integrated circuit. The source output enable signal SOE controls output timing of the data driver 130 .

The timing controller 140 is a source printed circuit board bonded with a source driver integrated circuit and a control printed circuit connected through a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit (FPC). It may be disposed on a board (Control Printed Circuit Board).

On such a control printed circuit board, a power controller (not shown) supplies various voltages or currents to the organic light emitting display panel 110, the gate driver 120, and the data driver 130 or controls various voltages or currents to be supplied. more can be placed. Such a power controller is also referred to as a power management integrated circuit.

Each subpixel SP disposed on the organic light emitting display panel 110 may include a circuit element such as a transistor.

For example, in the organic light emitting display panel 110, each subpixel SP is composed of an organic light emitting diode (OLED) and a circuit element such as a driving transistor (DRT) for driving the organic light emitting diode (OLED). may have been

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

2 illustrates an example of a sub-pixel (SP) structure of the organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 2 , in the organic light emitting display device 100 according to the present embodiments, each subpixel SP includes an organic light emitting diode OLED and a driving transistor DRT for driving the organic light emitting diode OLED. ) and a sensing transistor (SENT: Sensing Transistor) electrically connected between the first node (N1) of the driving transistor (DRT) and a reference voltage line (RVL) supplying a reference voltage (Vref: Reference Voltage). ), a switching transistor (SWT) electrically connected between the second node N2 of the driving transistor DRT and the data line DL supplying the data voltage Vdata, and the driving transistor DRT It is configured to include a storage capacitor (Cst: Storage Capacitor) electrically connected between the first node (N1) and the second node (N2) of the.

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

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

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

The sensing transistor SENT may be turned on by a gate signal to apply the reference voltage Vref to the first node N1 of the driving transistor DRT.

Also, when the sensing transistor SENT is turned on, it may be used as a voltage sensing path for the first node N1 of the driving transistor DRT.

When turned on by the gate signal, the switching transistor SWT transfers the data voltage Vdata supplied through the data line DL to the second node N2 of the driving transistor DRT.

In this case, the sensing transistor SENT and the switching transistor SWT may be connected to different gate lines GL to be separately controlled on-off or connected to the same gate line GL to be controlled.

The storage capacitor Cst is electrically connected between the first node N1 and the second node N2 of the driving transistor DRT to generate a data voltage Vdata corresponding to the image signal voltage or a voltage corresponding thereto. It can be maintained for one frame time.

Meanwhile, in the case of the organic light emitting display device 100 according to the present exemplary embodiments, as the driving time of each subpixel SP is increased, circuit elements such as an organic light emitting diode (OLED) and a driving transistor (DRT) Degradation may proceed.

Accordingly, inherent characteristic values (eg, threshold voltage, mobility, etc.) of circuit elements such as organic light emitting diodes (OLEDs) and driving transistors (DRTs) may change.

Such a change in the characteristic value of a circuit element causes a change in the luminance of the corresponding sub-pixel (SP), and the difference in the change in the characteristic value between the circuit elements due to the difference in the degree of deterioration between the circuit elements causes a luminance deviation between the sub-pixels (SP) and an organic light emitting display. This may cause deterioration in luminance uniformity of the panel 110 .

Here, the characteristic value of the circuit element includes the threshold voltage or mobility of the driving transistor DRT, and may also include the threshold voltage of the organic light emitting diode OLED.

The organic light emitting display device 100 according to the present embodiments includes a sensing function for sensing a characteristic value variation between subpixels SP or a characteristic value deviation between subpixels SP and a sensing result to detect subpixel SPs. A compensation function for compensating for the characteristic value of may be provided.

Hereinafter, a process of measuring and compensating for mobility among characteristic values of the driving transistor DRT in the organic light emitting display device 100 according to the present embodiments will be described with reference to FIGS. 2 to 4 .

Referring to FIG. 2 , in the organic light emitting display device 100 according to the present embodiments, in order to measure the mobility of the driving transistor DRT, a sensing reference voltage is applied to the first node N1 of the driving transistor DRT. The first node N1 and the second node N2 of the driving transistor DRT are connected by applying Vref and applying the data voltage Vdata for sensing and driving to the second node N2 of the driving transistor DRT. ) is initialized.

In the organic light emitting display device 100, after initializing the first node N1 and the second node N2 of the driving transistor DRT, the first node N1 and the second node of the driving transistor DRT are initialized. Floating all (N2).

Accordingly, the voltages of the first node N1 and the second node N2 of the driving transistor DRT increase, respectively, and the speed of this voltage increase depends on the current capability of the driving transistor DRT, that is, the mobility. may vary depending on

That is, as shown in FIG. 3, the voltage of the first node N1 rises, and after the voltage rises for a certain period of time, the voltage of the first node N1 is measured through the reference voltage line RVL. and the mobility of the driving transistor DRT can be determined based on the measured voltage.

The above-described mobility sensing may be performed at a predetermined timing, and, for example, as shown in FIG. 4 , it may be performed in real time by allocating a blank period, which is a period in which an image data voltage is not output when the screen is driven.

The organic light emitting display device 100 may compensate for a mobility deviation between the driving transistors DRT by calculating and applying a gain for compensating the mobility based on the measured mobility of the driving transistors DRT.

However, in the process of performing such mobility measurement and compensation, a ripple voltage of the reference voltage line (RVL) may be generated, and the ripple voltage of the reference voltage line (RVL) of the first node (N1) A screen defect of the organic light emitting display device 100 may be caused by affecting the voltage.

FIG. 5 shows that ripples are generated in the reference voltage Vref at the time of transition from a blank period in which mobility of the driving transistor DRT is measured to an active period.

Referring to FIG. 5 , the gate start pulse GSP is a signal that controls the operation start timing of the gate driver 120, and represents the point at which the gate driver 120 starts outputting a scan signal to the gate line GL. . 501 of FIG. 5 indicates the start point of the output of the scan signal, and indicates that the scan signal is output to the first gate line GL of the image displayed on the organic light emitting display panel 110 .

When the scan signal is output to the gate line GL, the data voltage Vdata is supplied to the data line DL according to the timing of the scan signal.

That is, an image data voltage for displaying an image is supplied through the data line DL according to the timing of the gate start pulse GSP, as shown in 503 .

A section before the image data voltage is supplied to the data line DL is a blank section, in which the black data voltage is supplied to the data line DL, and mobility of the driving transistor DRT is sensed in the blank section.

At the time of transition from the blank period to the active period where the image data voltage is output, the range of variation between the level of the data voltage (Vdata) output in the blank period and the level of the data voltage (Vdata) output in the active period is large, so that the reference voltage ( Ripple occurs in Vref) as in 502.

When a ripple occurs in the reference voltage Vref, the voltage at the first node N1 of the driving transistor DRT rises, and the data voltage Vdata applied to the second node N2 of the driving transistor DRT ), since the voltage of the first node N1 of the driving transistor DRT increases in a constant state, the voltage across the driving transistor DRT decreases.

As the voltage applied to the driving transistor DRT decreases, the current flowing through the organic light emitting diode OLED decreases, and the decrease in current flowing through the organic light emitting diode OLED causes a decrease in luminance. Therefore, a horizontal band defect occurs due to a decrease in luminance of the upper portion of the organic light emitting display panel 110 .

That is, the luminance of the organic light emitting diode (OLED) is lowered due to the ripple of the reference voltage (Vref) generated when the image data voltage is passed from the blank period to the active period. There is a problem in that the gray level according to the supplied data voltage Vdata cannot be accurately expressed.

The present embodiments provide a method of improving the ripple of the reference voltage Vref generated at the timing of transition from a blank period, which is a period for measuring the mobility of the driving transistor DRT, to an active period, and furthermore, data Provided is an organic light emitting display device 100 that improves image quality defects due to ripples generated from a voltage line associated with a line DL.

6 illustrates a schematic configuration of an organic light emitting display device 100 in which ripples generated in voltage lines are improved according to the present exemplary embodiments.

Referring to FIG. 6 , the organic light emitting display device 100 includes an organic light emitting display panel 110 , a gate driver 120 , a data driver 130 and a timing controller 140 .

A plurality of gate lines GL and a plurality of data lines DL are disposed in the organic light emitting display panel 110, and a plurality of voltage lines supplied with voltages output from the data driver 130 in addition to the data lines DL. (e.g. driving voltage line, reference voltage line) are arranged.

The gate driver 120 outputs a scan signal to drive the plurality of gate lines GL disposed on the organic light emitting display panel 110, and the data driver 130 receives the control signal and voltage received from the timing controller 140. Accordingly, voltages corresponding to each voltage line are supplied to the voltage lines disposed on the organic light emitting display panel 110 .

The timing controller 140 converts the video data received from the outside into the data signal format used by the data driver 120 and outputs it, and generates various control signals to operate the gate driver 120 and the data driver 130. to control

The timing controller 140 according to the present embodiments provides a function of improving ripple of a voltage line disposed on the organic light emitting display panel 110, and includes a control unit 141, a voltage output unit 142, A comparator 143 and a memory 144 may be included.

The controller 141 of the timing controller 140 outputs various control signals for driving the gate driver 120 and the data driver 130, and converts the voltage that is a reference voltage to the voltage output by the data driver 130 into a voltage. It is transmitted to the data driver 130 through the output unit 142 .

For example, the control unit 141 converts input image data according to the data signal format used by the data driver 130 so that the data driver 130 can output image data received from the outside, and outputs the data signal. The reference voltage Vref output from the driver 130 is designated and transmitted to the voltage output unit 142 .

The voltage output unit 142 outputs the voltage output from the data driver 130 to the data driver 130 according to the command of the control unit 141, and the data driver 130 is disposed on the organic light emitting display panel 110. A reference voltage (first voltage) of voltages output to the data line DL, the driving voltage line DVL, the reference voltage line RVL, etc. is output to the data driver 130.

The data driver 130 outputs a plurality of voltages disposed on the organic light emitting display panel 110 according to the first voltage received from the voltage output unit 142 when the gate line GL is driven by the gate driver 120 . A voltage (second voltage) corresponding to each voltage line is output as a voltage line.

For example, the image data voltage is supplied to the data line DL in accordance with the scan signal of the gate driver 120, and the reference voltage Vref is supplied to the reference voltage line ( RVL).

That is, when the control unit 141 of the timing controller 140 designates a first voltage that is a reference for the voltage output from the data driver 130 and transfers it to the data driver 130 through the voltage output unit 142, the data The driver 130 outputs a second voltage to a voltage line disposed on the organic light emitting display panel 110 according to the first voltage.

Accordingly, the first voltage and the second voltage should be at the same level, but may not be at the same level when a ripple occurs in the voltage output from the data driver 130 .

In the present embodiments, in order to improve such ripple, the voltage output unit 142 of the timing controller 140 supplies the second voltage, which is supplied from the data driver 130 to the voltage line disposed on the organic light emitting display panel 110. ) is compared with the first voltage output by

In the comparator 143 of the timing controller 140, the voltage output unit 142 outputs, to the data driver 130, a first voltage serving as a reference for the voltage output by the data driver 130, and according to the first voltage When the data driver 130 outputs the second voltage to the voltage line disposed on the organic light emitting display panel 110, the first voltage and the second voltage are received and levels of the two voltages are compared.

The comparator 143 transfers the result of comparing the first voltage and the second voltage to the control unit 141, and the control unit 141 adjusts the voltage level required to improve the ripple according to the received comparison result. .

In this case, the second voltage is a voltage supplied to the reference voltage line RVL disposed on the organic light emitting display panel 110 at a point in time when the data driver 130 passes from a blank period in which no image data voltage is output to an active period. can

That is, as described above, since the fluctuation range of the data voltage Vdata output from the data driver 130 is large at the time of transition from the blank period to the active period, the ripple of the reference voltage Vref occurs. The reference voltage Vref output at the time of transition from the period to the active period may be compared with the first voltage output from the voltage output unit 142 .

The control unit 141 may adjust the voltage level to improve ripple according to the comparison result between the first voltage and the second voltage, and may increase the data voltage level of some of the blank sections.

Specifically, the blank period is divided into a first period and a second period according to time order, and the data voltage level of the second period is adjusted according to the comparison result between the first voltage and the second voltage.

If there is a difference between the first voltage and the second voltage, since the voltage output from the data driver 130 is not the same as the voltage output by the voltage output unit 142, it can be seen that ripple has occurred. Therefore, if there is a difference between the first voltage and the second voltage, the data voltage level of the second section is increased by a predetermined level in the blank section.

If the data voltage level immediately before the start of the active period is increased, the range of fluctuation of the data voltage level at the time of transition from the blank period to the active period is reduced, thereby improving the ripple generated in the reference voltage (Vref). can

Thereafter, if the levels of the first voltage and the second voltage are the same as a result of comparing the first voltage and the second voltage, the data voltage level of the second section in the blank section is stored in the memory 144, and the blank is blanked according to the stored data voltage level. Controls the data voltage level of the section. Accordingly, the ripple of the reference voltage Vref generated at the time of transition from the blank period to the active period can be improved.

That is, in the present embodiments, while comparing the first voltage output from the voltage output unit 142 of the timing controller 140 and the second voltage output from the data driver 130, the blank period prevents ripple from occurring. This is a method of setting the data voltage level in , and this enables control to a data voltage level suitable for the corresponding panel regardless of the deviation that exists for each organic light emitting display panel 110 .

7 illustrates an example in which the control unit 141 of the timing controller 140 according to the present exemplary embodiments adjusts the data voltage level of the blank section according to the comparison result between the first voltage and the second voltage.

Referring to FIG. 7 , the control unit 141 compares the first voltage and the second voltage, and if there is a difference between the first voltage and the second voltage, the control unit 141 adjusts the data voltage level of a part of the blank section.

For example, the data voltage level in the blank section is set by increasing the data voltage level of the second section right before the image data voltage is output in the first section and the second section, which are divided according to the time order of the blank section. .

Accordingly, as shown in FIG. 7 , by increasing the level of the data voltage in the second section in the blank section, the range of variation in the data voltage at the timing of transition from the blank section to the active section can be reduced.

The control unit 141 raises the data voltage level of the second section in the blank section when there is a difference between the first voltage and the second voltage, and increases the data voltage level of the second section when there is no difference between the first voltage and the second voltage. maintain the voltage level.

By storing the data voltage level of the second section when there is no difference between the first voltage and the second voltage in the memory 144 and then controlling the data voltage level in the blank section according to the stored data voltage level, It is possible to prevent ripples generated from the reference voltage Vref from occurring at the timing of transition from the period to the active period. Therefore, when the image data voltage is output, the horizontal band defect at the upper part of the screen caused by the ripple of the reference voltage Vref can be improved.

FIG. 8 shows how ripple generated in the reference voltage Vref is improved by adjusting the data voltage level of the second section in the blank section according to the present embodiments.

Referring to FIG. 8 , according to a result of comparing the first voltage and the second voltage in the comparator 143 of the timing controller 140, the controller 141 determines the data voltage in a part of the blank section in which image data is not output. Adjust the level to 803.

Accordingly, in step 801 when the gate line GL is driven, the ripple generated in the reference voltage Vref can be improved as shown in step 802 .

Meanwhile, the present embodiments have been described focusing on the method of improving the ripple generated in the reference voltage (Vref) at the timing of transition from the blank period in which the image data voltage is not output to the active period, but the reference voltage (Vref) In addition, the ripple of other voltage lines connected to the data line DL can be improved in the same way to improve the effect of the ripple of the other voltage lines on the data voltage.

For example, the voltage output unit 142 of the timing controller 140 outputs a driving voltage EVDD of 24V to the data driver 130, and the comparator 143 outputs a driving voltage line DVL of the data driver 130. The voltage output as ) is compared with 24V, which is the voltage output by the voltage output unit 142.

At this time, if the voltage output from the data driver 130 is different from the 24V output from the voltage output unit 142, the controller 141 of the timing controller 140 controls the level of the driving voltage EVDD or the data voltage Vdata. ), the voltage output from the data driver 130 may be output at a constant level.

9 is a flowchart illustrating a process of a driving method of the organic light emitting display device 100 according to the present exemplary embodiments.

The timing controller 140 of the organic light emitting display device 100 converts a first voltage, which is a reference voltage supplied from the data driver 130 to a voltage line disposed on the organic light emitting display panel 110, to the data driver 130. It is output as (S900).

In this case, the first voltage may be the reference voltage Vref supplied to the reference voltage line RVL or the driving voltage EVDD supplied to the driving voltage line DVL.

The timing controller 140 compares the second voltage output from the data driver 130 according to the first voltage with the first voltage (S910).

As a result of comparing the first voltage and the second voltage, if a difference between the first voltage and the second voltage exists (S920), output to the data driver 130 to reduce the difference between the first voltage and the second voltage The voltage level is adjusted (S930).

For example, the second voltage is the reference voltage (Vref) supplied to the reference voltage line (Vref), and the data driver 130 outputs a voltage, the data voltage level of a part of the blank section may be adjusted according to a result of comparing the second voltage with the first voltage.

By adjusting the data voltage level of some sections in the blank section, the second voltage output by the data driver 130 at the time of transition from the blank section to the active section is the same as the first voltage, and the reference voltage generated at that time The ripple of (Vref) can be improved.

As a result of comparing the first voltage and the second voltage, if the first voltage and the second voltage are the same (S920), the currently set data voltage level is stored and the data voltage level is controlled according to the stored value (S940). Ripple of a voltage line disposed on the organic light emitting display panel 110 can be improved by controlling the level of a data voltage suitable for the light emitting display panel 110 .

According to the present embodiments, the output voltage of the timing controller 140 and the output voltage of the data driver 130 are compared at the time of transition from the blank period, which is the mobility measurement period of the driving transistor DRT, to the active period, and the comparison result The ripple of the reference voltage (Vref) generated at the time of transition from the blank period to the active period is improved by adjusting the data voltage level of some sections in the blank period according to It is possible to improve the transverse band defects that occur in

In addition, according to the present embodiments, when the voltage output by the timing controller 140 and the voltage output by the data driver 130 do not match, the output voltage of the data driver 130 is adjusted by adjusting the voltage level. to be able to control

The above description is merely illustrative of the technical idea of the present invention, and various modifications and variations will be possible to those skilled in the art without departing from the essential characteristics of the present invention. Since the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to explain, the scope of the technical idea of the present invention is not limited by these embodiments.

100: organic light emitting display device 110: organic light emitting display panel
120: gate driver 130: data driver
140: timing controller 141: control unit
142: voltage output unit 143: comparator
144: memory

Claims (13)

a data driver supplying a voltage corresponding to each voltage line to a plurality of voltage lines disposed on the organic light emitting display panel; and
The data driver outputs a first voltage, which is a reference for a voltage output to a reference voltage line among the plurality of voltage lines, to the data driver, and a second voltage output by the data driver according to the first voltage is the second voltage. 1 voltage, and sets a data voltage level supplied to one or more data lines among the plurality of voltage lines in a blank period in which the video data voltage is not output according to the comparison result.
An organic light emitting display device comprising a.
According to claim 1,
The timing controller,
The organic light emitting display device divides the blank period into a first period and a second period, and sets a data voltage level of the second period according to a comparison result between the first voltage and the second voltage.
According to claim 2,
The timing controller,
and if a difference between the first voltage and the second voltage exists, setting the data voltage level of the second section by increasing it by a predetermined level.
According to claim 2,
The timing controller,
and maintaining the data voltage level of the second section when the first voltage and the second voltage are equal to each other.
According to claim 1,
The timing controller,
An organic light emitting display device that compares the second voltage output with the first voltage at a point in time when the blank period is changed to a period in which the image data voltage is output.
outputting, by the data driver, a first voltage that is a reference voltage of a voltage output to a reference voltage line among a plurality of voltage lines by the data driver;
comparing a second voltage output from the data driver with the first voltage according to the first voltage; and
Setting a data voltage level supplied to a data line in a blank period in which no image data voltage is output according to a result of comparison between the first voltage and the second voltage.
A method of driving an organic light emitting display device comprising:
According to claim 6,
The step of comparing a second voltage output from the data driver according to the first voltage with the first voltage,
comparing the second voltage output by the data driver with the first voltage when a blank period in which the image data voltage is not output is changed to a period in which the image data voltage is output.
According to claim 6,
The step of setting the data voltage level of the blank section in which the image data voltage is not output,
and dividing the blank period into a first period and a second period, and increasing and setting a data voltage level of the second period when there is a difference between the first voltage and the second voltage.
According to claim 8,
The step of setting the data voltage level of the blank section in which the image data voltage is not output,
A method of driving an organic light emitting display device maintaining a data voltage level of the second section when the first voltage and the second voltage are equal to each other.
a voltage output unit outputting a first voltage that is a reference voltage of a voltage output to a reference voltage line among a plurality of voltage lines by the data driver;
a comparator comparing a second voltage output from the data driver with the first voltage according to the first voltage; and
The control unit sets the level of the data voltage supplied to the data line in the blank section in which the video data voltage is not output according to the comparison result between the first voltage and the second voltage.
A timing controller comprising a.
According to claim 10,
The control unit,
The timing controller divides the blank period into a first period and a second period, and sets a data voltage level of the second period according to a comparison result between the first voltage and the second voltage.
According to claim 11,
The control unit,
When a difference between the first voltage and the second voltage exists, the timing controller increases and sets the data voltage level of the second section.
According to claim 10,
The timing controller further includes a memory configured to store the data voltage level of the blank period set by the control unit.

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