KR102063989B1 - Organic light emitting display device and method of driving the same - Google Patents

Abstract

The present invention relates to an organic light emitting display device, and converts a P1 gray of P1 input image data corresponding to a P1 pixel into a P1 'gray larger than the P1 gray when a video data is input, and a P2 input corresponding to a P2 pixel. And a driver for converting the P2 gray of the image data into P2 'gray smaller than the P2 gray to drive the P1 pixel and the P2 pixels.

Description

Organic light emitting display device and its driving method {ORGANIC LIGHT EMITTING DISPLAY DEVICE AND METHOD OF DRIVING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device and a driving method thereof, which can solve a problem in which an afterimage occurs due to deterioration of an organic light emitting display panel.

Flat panel display devices (FPDs) are used in various types of electronic products, including mobile phones, tablet PCs, and notebook computers. The flat panel display device includes a liquid crystal display device (LCD), a plasma display panel device (PDP) and an organic light emitting display device (OLED). Display devices (EPDs) are also widely used.

Among them, OLEDs use self-light emitting devices that emit light by themselves, and thus have advantages such as fast response speed, high luminous efficiency, high luminance, and large viewing angle.

1 is an exemplary view showing a state in which a bright image and a dark image are output to an organic light emitting display panel applied to a conventional organic light emitting display device, and FIG. 2 is a view showing an organic light emitting display panel applied to a conventional organic light emitting display device. It is an exemplary figure for demonstrating the principle which the afterimage resulting from deterioration produces.

Since the organic light emitting diode display uses an organic light emitting diode (OLED), which is a self-luminous element, deterioration may occur due to various causes. If deterioration occurs and a deterioration difference between each pixel occurs, a difference in brightness and color is recognized, and a permanent afterimage remains.

Due to the self-luminous property of the organic light emitting diode OLED, when the same data of high brightness persists in the organic light emitting diode, deterioration of the organic light emitting diode occurs and the shape of the deteriorated pixels is recognized as an afterimage.

The afterimage becomes worse as the organic light emitting diode (OLED) deteriorates, and it is recognized that the organic light emitting diode has reached the end of its life at the point where the decrease in brightness is perceived by a human.

For example, in the organic light emitting display panel illustrated in FIG. 1A, a dark image, that is, a data voltage corresponding to about 50 gray is continuously supplied to a first region corresponding to 10. After the bright image, that is, the data voltage corresponding to the maximum gray 255 is continuously supplied to the second region corresponding to 20, as shown in FIG. 1B, the same data voltage is applied to the first region. When the same is supplied to the second region 20 and the second region 20, the second region 20 is expressed with a luminance lower than that of the first region 10. That is, the second region 20 driven for a long time with bright luminance deteriorates more than the first region 10, resulting in a dark afterimage.

As described above, an afterimage, in which a specific region is further degraded and is darker than a region in which degradation is not severe, may generally appear in an organic light emitting display device.

For example, as shown in (a) of FIG. 2, when a logo or various subtitles (hereinafter, simply referred to as 'logo') expressed at a very bright luminance is continuously output in a constant area X for a long time, The organic light emitting diode OLED of the area X in which the logo is output may deteriorate more than other areas. In this case, as shown in (b) of FIG. 2, even after the logo disappears, afterimage may occur, in which the area X appears darker.

In other words, it is impossible for all pixels of the organic light emitting display panel to be driven at the same luminance for a predetermined time. That is, a difference in driving time and luminance may occur for each pixel constituting the organic light emitting display panel. This difference may cause a difference in deterioration of the organic light emitting diodes formed in each pixel. When the organic light emitting diodes deteriorate differently, a phenomenon in which the output luminance decreases with respect to the input signal may occur in a pixel in which the deterioration is much progressed. In this case, even if all the pixels of the organic light emitting display panel are driven simultaneously with the data voltage corresponding to the same gray, the output luminance of each pixel may be different according to the difference in the degree of deterioration of the organic light emitting diode. The difference in luminance is represented by an afterimage.

Various compensation methods are used to prevent an afterimage caused by a difference in the degree of deterioration of the organic light emitting diode. However, even after the conventional compensation methods, the afterimage is not easily removed.

In particular, in order to reduce the afterimage caused by the difference in the degree of deterioration of the organic light emitting diode, a method of reducing the deterioration of the organic light emitting diode has been mainly studied. However, by the method of reducing the deterioration of the organic light emitting diode, the afterimage generated in the organic light emitting display panel cannot be easily removed.

The present invention has been proposed to solve the above-described problem, and the organic light emitting display device capable of eliminating an afterimage generated in the organic light emitting display panel by causing each pixel constituting the organic light emitting display panel to be further deteriorated. And it is a technical subject to provide the driving method.

In the organic light emitting display device according to the present invention for achieving the above technical problem, P1 pixels and P2 pixels for outputting the same color are formed adjacent to each other in the vertical direction of the horizontal lines formed in parallel with the gate lines An organic light emitting display panel; And converting P1 gray of the P1 input image data corresponding to the P1 pixel into P1 'gray larger than the P1 gray, and converting P2 gray of the P2 input image data corresponding to the P2 pixel to P2' smaller than the P2 gray. And a driving unit converting the P1 pixels and the P2 pixels to gray.

The organic light emitting display device driving method according to the present invention for achieving the above technical problem corresponds to the P1 pixels and P2 pixels outputting the same color, which are formed adjacent in the vertical direction of the horizontal lines parallel to the gate lines. Receiving input P1 input image data and P2 input image data; And converting P1 gray of the P1 input image data into P1 'gray larger than the P1 gray, and converting P2 gray of the P2 input image data into P2' gray smaller than the P2 gray, thereby converting the P1 pixel and the Driving the P2 pixels.

According to the present invention, since the difference in the degree of deterioration between the organic light emitting diodes constituting the pixels is reduced, the afterimage generated due to the difference in the degree of deterioration of the organic light emitting diodes can be reduced.

1 is a diagram illustrating a state in which a bright image and a dark image are output to an organic light emitting display panel applied to a conventional organic light emitting display device.
FIG. 2 is an exemplary diagram for describing a principle in which an afterimage caused by deterioration is generated in an organic light emitting display panel applied to a conventional organic light emitting display device.
3 is a configuration diagram of an organic light emitting display device according to an embodiment of the present invention.
4 is a flowchart illustrating an embodiment of a method of driving an organic light emitting display device according to the present invention;
5 and 6 are exemplary diagrams for describing a method of driving a panel by an organic light emitting display device driving method according to the present invention.
7 is a graph illustrating an example of deterioration of the organic light emitting display device and the conventional organic light emitting display device driving method according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

3 is a configuration diagram of an organic light emitting display device according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the organic light emitting diode display according to the present invention includes an organic light emitting display panel 100 including a plurality of pixels 110 and a driving unit for driving the organic light emitting display panel 100. . In the organic light emitting display panel 100, a pixel P 110 is formed at each intersection of the gate lines GL1 to GLg and the data lines DL1 to DLd. In addition, the driver is formed in the panel 100 and the gate driver 200 for sequentially supplying gate pulses to the gate lines GL1 to GLg formed in the organic light emitting display panel 100. A data driver 300 for supplying a data voltage to the data lines DL1 to DLd, and a timing controller 400 for controlling functions of the gate driver 200 and the data driver 300. .

First, in the organic light emitting display panel 100, pixels P 110 are formed in regions where a plurality of gate lines GL and a plurality of data lines DL cross each other. In the present invention, the gray of the pixel is changed in the pixel unit.

The pixel 110 may be one unit pixel or any one of a red subpixel, a green subpixel, and a blue subpixel constituting the unit pixel. In detail, the pixel 110 described below may be one unit pixel including the red subpixel, the green subpixel, and the blue subpixels, or the red subpixel and the green subpixel. Pixel, or blue sub-pixels. However, hereinafter, the present invention will be described with an example in which the pixel 110 is any one of the red subpixel, the green subpixel, and the blue subpixel. Accordingly, the present invention described below may be equally applied even when the pixel 110 is a unit pixel including the red subpixel, the green subpixel, and the blue subpixels.

In particular, the P1 and P2 pixels outputting the same color are formed adjacent to each other in the vertical direction of the horizontal lines formed parallel to the gate lines. That is, the horizontal line is an imaginary line formed parallel to the gate line, and a plurality of horizontal lines are formed in the vertical direction of the organic light emitting display panel 100.

For example, a plurality of pixels including the P1 pixel are formed in a first horizontal line of the horizontal lines, and a plurality of pixels including the P2 pixel are formed in a second horizontal line adjacent to the first horizontal line. The pixels are formed.

In this case, the P1 pixel and the P2 pixel are disposed in the organic light emitting display panel 100 to be adjacent to each other in the vertical direction. In detail, the P1 and P2 pixels output the same color, and the P1 and P2 pixels are formed on different horizontal lines adjacent to each other, and the P1 and P2 pixels are vertically disposed. It is formed to be adjacent to each other.

Each of the pixels 110 includes an organic light emitting diode (OLED) for outputting light and a pixel circuit 111 for driving the organic light emitting diode, as shown in the enlarged circle 1 of FIG. 3. do.

First, the organic light emitting diode includes a lower substrate, an anode formed on the lower substrate, an organic light emitting portion formed on the anode, and a cathode formed on the organic light emitting layer. .

The anode outputs light by a current transmitted by the driving transistor TFT2 formed in the pixel circuit 111, and an upper substrate is bonded to an upper end of the cathode. The anode may be composed of a transparent conductive material, for example, Indium Tin Oxide (ITO) (hereinafter simply referred to as 'ITO'). The cathode may also be composed of the ITO. In addition, one of the anode and the cathode may be formed of a metal thin film, for example, an aluminum thin film that performs a reflecting plate function. The organic light emitting diode may include a top emission method in which light generated by the organic light emitting diode is emitted to the outside through the upper substrate, and the light generated by the organic light emitting diode is used as the lower substrate. It can also be configured in a bottom emission (Bottom Emission) method that is emitted to. The top emission method or the bottom emission method may be determined depending on whether the reflector is formed on the anode or on the cathode.

The organic light emitting unit may include a hole transport layer (HTL), an emission material layer (EML), and an electron transport layer (ETL). In order to improve the luminous efficiency of the organic light emitting unit, a hole injection layer (HIL) may be formed between the cavity anode 118a and the hole transport layer HTL, and the cathode and the electron transport may be formed. An electron injection layer (EIL) may be formed between the films ETL.

The structure and function of the organic light emitting diode OLED are the same as the structure and function of the organic light emitting diode currently applied to a general organic light emitting diode display, and thus a detailed description thereof is omitted.

Second, the pixel circuit 111 may be connected to the data line DL and the gate line GL to store at least two transistors TR1 and TR2 and storage for controlling the organic light emitting diode OLED. It may be configured to include a capacitor (Cst).

The anode of the organic light emitting diode OLED is connected to the first power source VDD of the pixel circuit 111, and the cathode is connected to the second power source VSS of the pixel circuit 111. The organic light emitting diode OLED outputs light having a predetermined luminance in response to a current supplied from the driving transistor TR2.

The pixel circuit 111 controls the amount of current supplied to the organic light emitting diode OLED according to a data voltage supplied to the data line DL when a scan pulse is supplied to the gate line GL. .

To this end, the driving transistor TR2 is connected between the first power source VDD and the anode of the organic light emitting diode OLED, and the switching transistor TR1 is connected to the driving transistor TR2 and the data. It is connected between the line DL and the gate line GL.

Since the structure and function of the pixel circuit 111 are the same as the structure and function of the pixel circuit currently applied to an organic light emitting display device, a detailed description thereof will be omitted.

Next, the timing controller 400 may include a gate control signal GCS for controlling the gate driver 200 by using a vertical synchronization signal, a horizontal synchronization signal, and a clock supplied from an external system (not shown), and The data control signal DCS for controlling the data driver 300 is output.

The timing controller 400 samples the input image data input from the external system and rearranges the input image data, and supplies the rearranged digital image data to the data driver 300.

That is, the timing controller 400 rearranges input image data supplied from the external system, transmits the rearranged digital image data to the data driver 300, and horizontally synchronizes the clock supplied from the external system. A gate control signal (GCS) and the data driver 300 for controlling the gate driver 200 using a signal, a vertical synchronization signal (the clock and the signals are simply referred to as timing signals), and a data enable signal. Generates a data control signal (DCS) for controlling and transmits it to the gate driver 200 and the data driver 300.

In order to achieve the above object, the timing controller 400, the receiving unit for receiving the input image data and the various signals as described above from the external system, the input image data of the signals received from the receiving unit The image data processor for generating the rearranged digital image data and the gate for controlling the gate driver 200 and the data driver 300 by using the signals received from the receiver. A control signal generator for generating a control signal GCS and the data control signals DCS, and the image data and the control signals generated by the image data processor, the data driver 300 or the gate driver 200. It may be configured to include a transmitter for outputting.

In particular, the timing controller 400 converts P1 gray of the P1 input image data corresponding to the P1 pixel among the input image data input from the external system, into P1 'gray larger than the P1 gray, The P2 gray of the P2 input image data corresponding to the P2 pixel is converted into P2 'gray smaller than the P2 gray, thereby driving the P1 pixel and the P2 pixels. Such a function may be executed in the image data processor.

In addition, the timing controller 400 analyzes the input image data transmitted from the external system in at least one frame unit, and outputs a moving image to the organic light emitting display panel 100 by the input image data. If it is determined, the P1 'gray and the P2' gray are driven to drive the P1 pixel and the P2 pixel.

For example, the timing controller 400 may distinguish each frame by using at least one of the various signals input to the timing controller 400, and may input the input image data in units of at least one frame. The analysis may determine whether a video is output or a still image is output by the input image data.

This determination may be made by using whether the number of input image data having the same or similar value among the input image data forming at least two or more frames is larger than a preset number. Can be done. The determination may be made by the receiver, the image data processor, or a determiner formed between the receiver and the image data processor.

However, when it is determined that the video is output to the organic light emitting display panel 100 by the input image data, the timing controller 400 sets the P1 'gray to a value equal to or corresponding to the P1 gray. And converts the P2 'gray to a value equal to or corresponding to the P2 gray.

In addition, the timing controller 400 may set the P1 'gray and the P2' gray differently according to whether the sum of the luminances of the P1 gray and the P2 gray is greater than a preset reference luminance.

For example, the timing controller 400 determines whether the sum luminance of the P1 gray and the P2 gray is greater than a preset reference luminance, and when the timing controller 400 is larger, converts the P1 'gray to the maximum gray, and The P1 pixel and the P2 pixel may be driven by converting the P2 'gray smaller than the P2 gray. In addition, the timing controller 400 determines whether the sum of the luminances of the P1 gray and the P2 gray is greater than a preset reference luminance, and when the sum is less than or equal to, the luminance of the P1 pixel corresponds to the sum luminance. The P1 gray may be converted to the P1 'gray and the P2' gray may be converted to 0 so as to have luminance, thereby driving the P1 pixel and the P2 pixel.

Here, the reference luminance may be any one of luminance of light output through the P1 pixel and the P2 pixel. For example, the reference luminance may be luminance when a data voltage corresponding to 255 gray is output to each of the P1 and P2 pixels. Accordingly, the reference luminance may be set in a manufacturing process of the organic light emitting display device according to the present invention and then stored in a memory inside the timing controller or outside the timing controller.

The function may be executed in the image data processor.

In addition, the timing controller 400 converts P1 gray of the P1 input image data to P1 'gray smaller than the P1 gray when the preset first conversion period arrives using a timer, and inputs the P2. P2 gray of the image data may be converted into P2 'gray larger than the P2 gray to drive the P1 pixel and the P2 pixels. In addition, the timing controller 400 resets the timer after the preset second conversion period after the first conversion period, and then resets the P1 gray of the P1 input image data to P1 larger than the P1 gray. When the first conversion period arrives, the process of driving the P1 pixels and the P2 pixels by converting to gray and converting P2 gray of the P2 input image data to P2 smaller than the P2 gray You can repeat until.

The timing controller 400 may configure the timer using at least one of the signals input from the external system. That is, the timer performs a function of determining the first conversion period or the second conversion period using the signals.

The first conversion period and the second conversion period may be set in units of frames, or may be set in minutes, hours, or days. Information about the first conversion period and the second conversion period may be stored in a memory inside the timing controller or outside the timing controller.

In detail, the timing controller 400, more specifically, the image data processing unit may include the P1 input image data to be output as the P1 pixel when the image output to the organic light emitting panel 100 is a video. The P1 gray is converted into the P1 'gray to generate P1 image data having the P1' gray. The image data processing unit converts the P2 gray of the P2 input image data to be output as the P2 pixel into the P2 'gray to generate P2 image data having the P2' gray. The timing controller 400 transmits the P1 image data and the P2 image data to the data driver 300.

Specific functions of the timing controller will be described in detail below with reference to FIGS. 4 to 6.

Next, the data driver 300 converts the image data input from the timing controller 400 into an analog data voltage, so that one horizontal line of data voltage is supplied every horizontal period in which the scan pulse is supplied to the gate line. Is supplied to the data lines. That is, the data driver 300 converts the image data into a data voltage using gamma voltages supplied from a gamma voltage generator (not shown) and outputs the data voltages to the data lines.

That is, the data driver 300 generates a sampling signal by shifting a source start pulse SSP from the timing controller 400 according to a source shift clock SSC. The data driver 300 latches the image data input according to the source shift clock SSC according to a sampling signal, converts the image data into a data voltage, and then supplies the source output enable SOE. The data voltage is supplied to the data lines in horizontal line units in response to a signal.

To this end, the data driver 300 may include a shift register unit, a latch unit, a digital analog converter, an output buffer, and the like.

The shift register unit outputs a sampling signal using data control signals received from the timing controller 400.

The latch unit latches the digital image data sequentially received from the timing controller 400, and simultaneously outputs the digital image data to the digital analog converter.

The digital-analog converter converts the image data transmitted from the latch unit into a data voltage and outputs the converted data voltage. That is, the digital-to-analog converter converts the image data into the data voltage and outputs the data voltages to the data lines using a gamma voltage supplied from the gamma voltage generator (not shown).

The output buffer outputs the data voltage transmitted from the digital analog converter to the data lines DL of the panel according to the source output enable signal SOE transmitted from the timing controller 400. .

Particularly, among the image data transmitted from the timing controller 400 to the data driver 300, the P1 image data output as the P1 pixel includes information about the P1 'gray, and the P2 pixel. The output P2 image data includes information on the P2 'gray.

The data driver 300 generates a P1 'data voltage corresponding to the P1' gray and transmits it to the P1 pixel, and generates a P2 'data voltage corresponding to the P2' gray and transmits the data voltage to the P2 pixel.

Lastly, the gate driver 200 sequentially supplies scan pulses to the gate lines GL1 to GLg of the panel 100 in response to the gate control signal input from the timing controller 400. Accordingly, the switching transistors formed in each subpixel of the corresponding horizontal line to which the scan pulse is input may be turned on, and an image may be output to each pixel 110.

That is, the gate driver 200 shifts a gate start pulse (GSP) transmitted from the timing controller 400 according to a gate shift clock (GSC), and sequentially shifts the gate lines. Scan pulses having a gate-on voltage are supplied to GL1 to GLg. In addition, the gate driver 200 supplies a gate-off voltage to the gate lines GL1 to GLn for the remaining period during which the scan pulse is not supplied.

The gate driver 200 may be formed to be independent of the panel 100 and may be configured to be electrically connected to the panel 100 in various ways. However, the gate may be mounted in the panel 100. It may be configured by a gate in panel (GIP) method. In this case, the gate control signal for controlling the gate driver 200 may be a start signal VST and a gate clock GCLK.

In addition, in the above description, the data driver 300, the gate driver 200, and the timing controller 400 are described as independently configured, but at least one of the data driver 300 or the gate driver 200 may be used. One may be integrally formed with the timing controller 400. In the following description, the gate driver 200, the data driver 300, and the timing controller 400 are collectively referred to as a panel driver.

4 is a flowchart illustrating a method of driving an organic light emitting display device according to an exemplary embodiment of the present invention, and FIGS. 5 and 6 are exemplary views illustrating a method of driving a panel by the method of driving an organic light emitting display device according to the present invention. .

First, in the method of driving the organic light emitting display device according to the present invention, the time T is reset by the timer (402). The timer may be configured using at least one of the signals input from the external system. The timing controller 400 resets the time T to be used in the timer.

Second, the driver, in particular, the timing controller 400 corresponds to the P1 pixels and the P2 pixels that output the same color, which are formed to be adjacent to each other in the vertical direction of the horizontal lines parallel to the gate lines. The P1 input image data and the P2 input image data are received from the external system (404).

The P1 pixel P1 and the P2 pixel P2 are adjacent to each other in the vertical direction as illustrated in FIG. 5. In FIG. 5, only the P1 pixel P1 and the P2 pixel P2 are illustrated, but a plurality of pixels are formed in the organic light emitting panel 100 in a direction parallel to the P1 pixel P1. Also, a plurality of pixels are formed in a direction parallel to the P2 pixels P2. In this case, the pixels formed parallel to the P1 pixels P1 and P1 pixels P1 are formed on the first horizontal line, and the P2 pixels P2 and P2 pixels P2 are formed on the first horizontal line. Pixels formed in parallel with each other are formed in the second horizontal line. Hereinafter, for convenience of description, the first horizontal line is called an odd line, and the second horizontal line is called an even line.

The P1 input image data may include various information including gray and color of an image to be output as the P1 pixel.

Third, the timing controller 400 converts the P1 gray of the P1 input image data into P1 'gray larger than the P1 gray, and converts the P2 gray of the P2 input image data to P2' smaller than the P2 gray. The gray pixel is driven to drive the P1 pixel and the P2 pixels. The process is described in more detail as follows.

First, the timing controller 400 analyzes the input image data transmitted from the external system in at least one frame unit so that a video is output to the organic light emitting display panel 100 by the input image data. It is determined whether it is determined (406).

Next, when it is determined that the still image is output to the organic light emitting display panel 100, the timing controller 400 may include the P1 input image data and the P2 input image data, and the P1 image data and the P1 input image data. Convert to P2 image data. In this case, the P1 image data includes the P1 'gray having the same value as the P1 gray, and the P2 image data includes the P2' gray having the same value as the P2 gray. In this case, the P1 'gray and the P2' gray may be a value increased by the same ratio from the P1 gray and the P2 gray or may be a value reduced by the same ratio.

The timing controller 400 transmits the P1 image data and the P2 image data to the data driver 300.

The data driver 300 converts the P1 image data into the P1 data voltage and supplies the P1 data voltage to the P1 pixel while the scan pulse is supplied to a gate line corresponding to the first horizontal line. do. The data driver 300 converts the P2 image data into the P2 data voltage, and then converts the P2 data voltage to the P2 pixel while the scan pulse is supplied to a gate line corresponding to the second horizontal line. To feed.

Next, when it is determined that the video is output to the organic light emitting display panel 100, the timing controller 400 calculates the summed luminance B_sum of the P1 gray and the P2 gray (416). . The sum luminance B_sum is a sum value of the luminance B-P1 of light output from the P1 pixel by the P1 gray and the luminance B_P2 of light output from the P2 pixel by the P2 gray. 4, the sum luminance is calculated by simply summing the luminance B-P1 of the light output from the P1 pixel and the luminance B_P2 of the light output from the P2 pixel by the P2 gray. Although the sum luminance is calculated by a complicated calculation formula.

For example, light having the maximum luminance (for example, 500 nits (nt)) is output from the P1 pixel, and light having the maximum luminance (500 nits (nt)) is output from the P2 pixel. The P1 and P2 pixels do not output a luminance (1000 nits) corresponding to twice the maximum luminance. However, hereinafter, for convenience of explanation, except for special cases, the present invention will be described as the sum of the luminance of the light output from the two pixels being the sum luminance.

Accordingly, the timing controller 400 may add luminances of grays used in the organic light emitting display panel and summed luminances of light output by two grays of the grays to calculate the aggregated luminance B_sum. You can use a lookup table that stores information about these fields. In addition, the timing controller 400 may use the calculation formula for calculating the sum luminance using two grays, and the sum luminance of the light output from the P1 pixel and the P2 pixel by the P1 gray and the P2 gray. (B_sum) can be calculated. The lookup table may be stored in the timing controller 400 or in a memory outside the timing controller 400.

For example, a sum luminance when light corresponding to the P1 gray and the P2 gray is output may be stored in the lookup table, and the timing controller may include the sum luminance (B_sum) in the lookup table. Can be extracted.

As another example, the lookup table may store a sum of luminance when light having a size similar to that of the P1 gray and light corresponding to a gray having a size aborted with the P2 gray is output. In this case, the timing controller 400 extracts the sum luminance stored in the lookup table, and then corrects the sum luminance using a predetermined calculation formula, thereby adding sum luminance by the P1 gray and the P2 gray. B_sum) can be calculated.

As another example, the timing controller calculates the sum of the luminances B_sum of the P1 gray and the P2 grays by using a calculation formula for calculating the sum of the luminances of the two grays using two grays. can do.

Next, the timing controller 400 determines whether the sum luminance B_sum is larger than the preset reference luminance B_ref (418). As described above, the reference luminance may be a luminance when a data voltage corresponding to 255 gray is output to each of the P1 and P2 pixels. The reference luminance may be a luminance when a data voltage corresponding to 255 gray (G = 255), which is the maximum gray of the pixels, is output to the P1 pixel or the P2 pixel.

Next, as a result of the determination, when the sum luminance B_sum is greater than the preset reference luminance B_ref, the timing controller 400 maximizes the P1 'gray as shown in FIG. 5. After converting to gray, converting the P2 'gray to smaller than the P2 gray, and using the P1 data voltage corresponding to the P1' gray and the P2 data voltage corresponding to the P2 'gray, the P1 pixel (P1) and the P2 pixel P2 are driven (420).

For example, hereinafter, as shown in FIG. 5, it is assumed that the reference luminance B_ref is a maximum value of luminances output from the pixels, and the reference luminance B_ref is 100%. In addition, the P1 gray G_P1 outputted to the P1 pixel P1 is 220, the luminance B_P1 of light outputted to the P1 pixel P1 by the P1 gray G_P1 is 80%, and the P2. It is assumed that the P2 gray G_P2 outputted to the pixel P2 is 200 and the luminance B_P2 of light outputted to the P2 pixel P2 by the P2 gray G_P2 is 70%.

In this case, the sum of the luminance of the light output from the two pixels does not coincide with the sum of the two luminances B_P1 and B_P2. Hereinafter, for convenience of description, the two pixels P1 and P2. The summation of the luminances B_P1 and B_P2 of the light output from the X) becomes the summed luminance B_sum.

Under the assumptions described above, when the sum luminance B_sum of the P1 gray and the P2 gray is 150%, the sum luminance B_sum has a value larger than the reference luminance B_ref. That is, the luminance output from the two pixels is greater than the reference luminance.

In this case, the timing controller 400 converts the P1 'gray G_P1' to the maximum gray 255 and converts the P2 'gray G_P2' to be smaller than the P2 gray G_P2. The P1 pixel P1 and the P2 pixel P2 are formed by using the P1 data voltage corresponding to the P1 'gray G_P1' and the P2 data voltage corresponding to the P2 'gray G_P2'. Drive it.

In the P1 pixel P1, the maximum brightness B_P1 '= B_max = 100% is output by the P1' gray G_P1 'corresponding to the maximum gray 255. In the P2 pixel P2, A luminance B_P2 '= B_sum-B_max = 50% corresponding to the P2' gray G_P2 'is output.

In this case, the overall luminance (150%) due to the light output from the two pixels P1 and P2 is unchanged, and the luminance of the P1 pixel P1 is increased from 80% to 100%, and the P2 The luminance of the pixel P2 was reduced to 50%. That is, the luminance B_P2 '= 50% of the P2 pixel P2 may be a value obtained by subtracting the maximum luminance B_P1' = B_max = 100% from the sum luminance B_sum.

Therefore, if the above process is continuously generated, deterioration may occur severely in the organic light emitting diode constituting the P1 pixel P1.

Finally, when the sum luminance B_sum is less than or equal to the preset reference luminance B_ref, the timing controller 400 displays the P1 pixel as shown in FIG. 6. The P1 gray G_P1 is converted into the P1 'gray G_P1' and the P2 'gray G_P2' is converted to 0 such that the luminance B_P1 'of (P1) has a brightness corresponding to the sum luminance. In operation 422, the P1 pixel P1 and the P2 pixel P2 are driven (424).

For example, hereinafter, as shown in FIG. 6, it is assumed that the reference luminance B_ref is a maximum value of luminances output from the pixels, and the reference luminance B_ref is 100%. In addition, the P1 gray G_P1 outputted to the P1 pixel P1 is 60, the luminance B_P1 of light outputted to the P1 pixel P1 by the P1 gray G_P1 is 40%, and the P2. It is assumed that the P2 gray G_P2 output to the pixel P2 is 30, and the brightness B_P2 of light output to the P2 pixel P2 by the P2 gray G_P2 is 30%.

In this case, the sum of the luminance of the light output from the two pixels does not coincide with the sum of the two luminances B_P1 and B_P2. Hereinafter, for convenience of description, the two pixels P1 and P2. The summation of the luminances B_P1 and B_P2 of the light output from the X) becomes the summed luminance B_sum.

Under the assumptions described above, when the sum luminance B_sum of the P1 gray and the P2 gray is 70%, the sum luminance B_sum has a smaller value than the reference luminance B_ref. That is, the luminance output from the two pixels is smaller than the reference luminance.

In this case, the timing controller 400 sets the P1 gray (G_P1 = 60) to the P1 'gray (G_P1' = 200) such that the luminance of the P1 pixel has a brightness corresponding to the sum luminance (70%). The P2 'gray (G_P2' = 40) is converted to 0 (422) to drive the P1 pixel (P1) and the P2 pixel (P2) (424).

In the P1 pixel P1, a luminance B_P1 '= 70% larger than the luminance output by the P1 gray G_P1 = 60 is output by the P1' gray G_P1 '= 200, and the P2 In the pixel P2, the luminance B_P2 'becomes zero.

In this case, the overall luminance (70%) due to the light output from the two pixels P1 and P2 is unchanged, and the luminance of the P1 pixel P1 is increased from 40% to 70%, and the P2 The luminance of the pixel P2 was reduced from 30% to 0%.

Therefore, if the above process is continuously generated, deterioration may occur severely in the organic light emitting diode constituting the P1 pixel P1.

The present invention, as described above, by increasing the luminance of any one of the two pixels adjacent to each other than the original brightness, thereby deteriorating the pixels with increased brightness more quickly, to reduce the afterimage generated by degradation It is characterized by.

However, by the above process, only one pixel of the two pixels, that is, the P1 pixel, emits light with high luminance, so that only the P1 pixel is deteriorated. Therefore, assuming that the P1 pixel is formed in the odd line, only the pixels formed in the odd line deteriorate. In this case, the degree of deterioration of the pixels formed in the odd line and the pixels formed in the even line may be different. Accordingly, an afterimage may occur due to the odd line and the even line.

In order to prevent this, the present invention repeatedly increases the luminance of the P1 pixel, thereby increasing the degradation of the P1 pixel, and increasing the luminance of the P2 pixel, thereby increasing the degradation of the P2 pixel. I'm doing it.

That is, according to the present invention, when it is determined that the preset first conversion period T1 has not arrived by using a timer (406), P1 gray of the P1 input image data is changed to P1 'gray larger than the P1 gray. Converting P2 gray of the P2 input image data into P2 'gray smaller than the P2 gray to drive the P1 pixel and the P2 pixels (408, 412, 416, 418, 420, 422), If it is determined that the first conversion period has arrived (406), P1 gray of the P1 input image data is converted into P1 'gray smaller than the P1 gray, and P2 gray of the P2 input image data is converted into the P2 gray. Driving the P1 pixel and the P2 pixels by converting to a larger P2 'gray (410, 412, 416, 418, 420, 422) and after the first conversion period, a second preset conversion period T2 When it arrives (426), the timer is reset and the P1 input image is reset. P1 gray of the data is converted into P1 'gray larger than the P1 gray, and P2 gray of the P2 input image data is converted into P2' gray smaller than the P2 gray to drive the P1 pixel and the P2 pixels. The process may be repeated until the first conversion period arrives.

First, when it is determined that the preset first conversion period T1 has not arrived (406), the timing controller 400 executes the above-described process as it is.

In this case, the timing controller 400 defines pixels of odd lines as the P1 pixels and pixels of even lines as the P2 pixels (4008).

Therefore, while the first conversion period T1 does not arrive, the luminance of the P1 pixel becomes higher than the luminance of the P2 pixel through the processes described with reference to FIGS. 5 and 6. As a result, deterioration of pixels formed in the odd-numbered lines including the P1 pixel proceeds.

Second, when it is determined that the first conversion period has arrived (406), the timing controller 400 defines an even line of pixels as the P1 pixel and an odd line of pixels as the P2 pixel ( 410).

In this case, the timing controller 400 converts P1 gray of the P1 input image data to P1 'gray smaller than the P1 gray, and converts P2 gray of the P2 input image data to P2' larger than the P2 gray. The gray pixel is driven to drive the P1 pixel and the P2 pixels.

Therefore, the luminance of the P2 pixel becomes higher than the luminance of the P1 pixel through the processes described with reference to FIGS. 5 and 6 for a predetermined period after the first conversion period T1 arrives. As a result, deterioration of pixels formed in the even lines is performed, including the P2 pixel.

Third, when the preset second conversion period T2 arrives after the first conversion period T1 (426), the timing controller 400 resets the timer (402), and then the P1 input image. Converting the P1 gray of the data to P1 'gray larger than the P1 gray, and converting the P2 gray of the P2 input image data to P2' gray smaller than the P2 gray to drive the P1 pixel and the P2 pixels. The process is repeated until the first conversion period T1 comes again.

That is, the timing controller 400 increases the luminance of the P1 pixels formed in the odd lines until the first conversion period T1 arrives, thereby increasing the P1 pixels formed in the odd lines. It degrades more than the P2 pixels formed in even lines.

In addition, the timing controller 400 may determine whether the P2 pixels formed in the even lines are 426 until the second conversion period T2 arrives after the first conversion period T1 arrives. By increasing the luminance, the P2 pixels formed on the even lines are further degraded than the P1 pixels formed on the odd lines.

In addition, when the second conversion period T2 arrives (426), the timing controller 400 resets the timer again, and P1 pixels formed on the odd lines are formed on even lines. Worse than the P2 pixels.

The timing controller 400 repeats the above-described processes during the first conversion period and the second conversion period, thereby forming P1 pixels formed in the odd lines and the even lines. All of the P2 pixels present can deteriorate faster.

Since the pixels deteriorate faster than pixels formed in a general organic light emitting display, afterimages due to differences in degree of deterioration may be reduced.

7 is a graph illustrating an example of deterioration of the organic light emitting display device according to the present invention and a method of driving the conventional organic light emitting display device. In FIG. 7, a graph shown as a diamond-shaped point and displayed as a "existing driving method" is a graph of deterioration by a conventional organic light emitting display driving method, and is shown as a dot in a square shape and represented by a "Pixel bininig method". The graph is a graph of deterioration according to the present invention.

The organic light emitting display device driving method according to the present invention described above is summarized as follows.

First, in the present invention, the sum of the luminances Ri1 + Ri2 when driving two adjacent pixels of the same color is less than or equal to the luminance R = 1 when driving only one pixel separately. In this case, only one pixel is driven to be equal to the sum of luminances Ri1 + Ri2 when the two adjacent pixels are driven, and the other one is not driven.

Second, if the sum of the luminances Ri1 + Ri2 when driving two adjacent pixels of the same color is larger than the luminance R = 1 when driving only one pixel separately, Pixel is driven at 100%, and the other pixel is the sum of luminance when driving both pixels (Ri1 + Ri2) minus the luminance when driving one pixel at 100% ( Drive as much as Ri1 + Ri2-1).

Third, the present invention converts a sequence of pixels of increasing luminance and pixels of decreasing luminance when a certain period of time passes. Thus, a pixel whose luminance has been increased during the first period is reduced in brightness during the second period, and a pixel whose luminance has been decreased during the first period is increased in brightness during the second period.

In the conventional organic light emitting display device driving method, deterioration proceeds by the same deterioration curve as in the conventional driving method shown in FIG. 7. That is, when the organic light emitting display panel is driven by the conventional driving method, since each of the pixels is driven, the average value of the degree of deterioration of the entire organic light emitting display panel is shown by the conventional driving method shown in FIG. It is calculated like a curve.

However, when the organic light emitting display panel is driven by the pixel binning method of the present invention, since two adjacent pixels of the same color are driven differently, the average value of the degree of deterioration according to the present invention is conventional. It is calculated to be different from the deterioration curve of.

The average value of the degree of deterioration according to the present invention can be calculated as follows. The following

In the description, Rix and R0x are normalized digital luminance values of the pixels Pix, P0x, where Rix is the brightness before conversion, ROX is the brightness after conversion, Pix is the pixel before conversion, and POx is after conversion Pixels.

First, if the sum of luminance (Ri1 + Ri2) when driving two adjacent pixels of the same color is all equal to or smaller than the luminance (R = 1) when driving only one pixel separately 100%, Among the luminances R01 and R02 changed by the invention, R01 = Ri1 + Ri2 = 2 * Ri1 (Ri1 = Ri2), and R02 = 0. Therefore, the degree of deterioration of the pixel 1 P01 after conversion has a deterioration value corresponding to twice the driving luminance of the pixel 1 Pi1 before conversion, and the degree of deterioration of the pixel 2 P02 after conversion is 0%. do.

Second, if the sum (Ri1 + Ri2) of the luminance when driving two adjacent pixels of the same color is all greater than the luminance (R = 1) when driving only one pixel separately 100%, R01 = 1 among the luminances R01 and R02 changed by this, and R02 = Ri1 + Ri2-1. Therefore, the degree of deterioration of pixel 1 (P01) after conversion is 100%, and the degree of deterioration of pixel 2 (P02) after conversion is equal to the remaining drive luminance after subtracting 100% from the driving luminance of pixel 1 (Pi1) before conversion. The corresponding degradation degree value is also.

By degrading the two deterioration values calculated as described above, the deterioration degree when driven by the driving method according to the present invention can be calculated.

As can be seen from FIG. 7, the organic light emitting display device is driven by the organic light emitting display device driving method according to the present invention rather than the organic light emitting display device is driven by the conventional organic light emitting display device driving method. At the same luminance, the relative average degradation is generally higher.

That is, the relative average deterioration degree according to the present invention is further improved by the deterioration curve when the organic light emitting display device is driven by the present invention is above the deterioration curve by the conventional organic light emitting display device driving method. It can be seen that high.

In general, afterimages due to deterioration occur because deterioration proceeds more in a region having a higher driving luminance than a peripheral region. Therefore, the present invention can reduce the afterimage by increasing the degree of deterioration of the organic light emitting diodes overall and reducing the difference in the degree of deterioration of each pixel.

In detail, according to the present invention, deterioration of the organic light emitting diodes forming each pixel may proceed more quickly. Accordingly, the difference in degradation of the organic light emitting diodes constituting the organic light emitting display panel is reduced. As the difference in deterioration of each region of the organic light emitting display panel decreases, afterimages due to the difference in deterioration may be reduced.

That is, the present invention is a method of controlling the luminance of two adjacent pixels of the same color in order to reduce the degree of afterimage, which is generated by driving respective regions of the organic light emitting display panel to output different luminance. . According to the present invention, the level of deterioration of each region of the organic light emitting display panel is quickly leveled, so that the difference in deterioration of the respective regions can be reduced, and accordingly, afterimages due to deterioration can be reduced.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

100 panel 200 gate driver
300: data driver 400: timing controller

Claims (10)

An organic light emitting display panel in which P1 pixels and P2 pixels that output the same color are formed adjacent to each other in a vertical direction of horizontal lines formed parallel to the gate lines; And
If it is determined that the video is output to the organic light emitting display panel by analyzing the input image data in at least one frame unit, the P1 gray of the P1 input image data corresponding to the P1 pixel is smaller than the P1 gray. An organic light source including a driving unit which converts the P2 gray of the P2 input image data corresponding to the P2 pixel to a smaller P2 'gray than the P2 gray, and drives the P1 pixel and the P2 pixels Light emitting display device. delete The method of claim 1,
The driving unit,
And the P1 'gray and the P2' gray are set differently according to whether the sum of the luminances of the P1 gray and the P2 gray is larger than a preset reference luminance. The method of claim 1,
The driving unit,
It is determined whether the sum of the luminances of the P1 gray and the P2 gray is greater than a predetermined reference luminance, and when large, the P1 'gray is converted to the maximum gray, and the P2' gray is converted to be smaller than the P2 gray, Driving the P1 pixel and the P2 pixel;
In the case of being smaller or equal, the P1 gray is converted into the P1 'gray and the P2' gray is converted to 0 so that the luminance of the P1 pixel has the luminance corresponding to the sum luminance, and the P1 pixel and the P2 pixel are converted into zero. And an organic light emitting display device. The method of claim 1,
The driving unit,
When a preset first conversion period arrives using a timer, P1 gray of the P1 input image data is converted into P1 'gray smaller than the P1 gray, and P2 gray of the P2 input image data is converted into P2 gray. Convert to larger P2 'gray to drive the P1 pixels and the P2 pixels,
After the first conversion period, when the preset second conversion period arrives, the timer is reset, and then P1 gray of the P1 input image data is converted into P1 'gray larger than the P1 gray, and the P2 input image is reset. Converting the P2 gray of the data into a P2 'gray smaller than the P2 gray to drive the P1 pixels and the P2 pixels until the first conversion period arrives. Device. The method of claim 1,
The P1 pixel and each of the P2 pixels,
A unit pixel consisting of a red subpixel, a green subpixel, and a blue subpixel, or
The organic light emitting display device of any one of a red sub pixel, a green sub pixel, and a blue sub pixel. Receiving P1 input image data and P2 input image data corresponding to P1 pixels and P2 pixels outputting the same color, which are formed adjacent in the vertical direction of horizontal lines parallel to the gate lines; And
If it is determined that the video is output to the organic light emitting display panel by analyzing the input image data in at least one frame unit, P1 gray of the P1 input image data is converted into P1 'gray larger than the P1 gray. And converting P2 gray of the P2 input image data into P2 'gray smaller than the P2 gray to drive the P1 pixel and the P2 pixels. delete The method of claim 7, wherein
The driving of the P1 pixel and the P2 pixels may include:
Determining whether a sum luminance of the P1 gray and the P2 gray is greater than a preset reference luminance;
As a result of the determination, converting the P1 'gray to the maximum gray and converting the P2' gray smaller than the P2 gray to drive the P1 pixel and the P2 pixel; And
As a result of the determination, when the size is smaller than or equal to, the P1 gray is converted into the P1 'gray and the P2' gray is converted to 0 so that the luminance of the P1 pixel has the luminance corresponding to the sum luminance. And driving the P2 pixel. The method of claim 7, wherein
The driving of the P1 pixel and the P2 pixels may include:
If it is determined that the preset first conversion period has not arrived using a timer, P1 gray of the P1 input image data is converted into P1 'gray larger than the P1 gray, and P2 gray of the P2 input image data is converted. Converting the P1 pixel and the P2 pixels to P2 'gray smaller than the P2 gray;
If it is determined that the first conversion period has arrived, P1 gray of the P1 input image data is converted into P1 'gray smaller than the P1 gray, and P2 gray of the P2 input image data is larger than P2 gray. 'Converting to gray to drive the P1 pixels and the P2 pixels; And
After the first conversion period, when the preset second conversion period arrives, the timer is reset, and then P1 gray of the P1 input image data is converted into P1 'gray larger than the P1 gray, and the P2 input image is reset. Converting the P2 gray of the data into P2 'gray smaller than the P2 gray to drive the P1 pixels and the P2 pixels until the first conversion period arrives. How to drive the device.

Images