KR102045807B1 - Organic light emitting display and method of driving the same - Google Patents

Abstract

The present invention relates to an organic light emitting display device and a driving method thereof capable of reducing manufacturing cost by reducing memory for external compensation, and reducing power consumption and heat generation.
An organic light emitting display device according to an embodiment of the present invention includes a display panel in which a plurality of pixels are arranged; A gate driver supplying a scan signal and a sensing signal to the plurality of pixels; A data driver supplying a data voltage to the plurality of pixels and sensing characteristics of the plurality of pixels; A compensation memory storing compensation data for compensating for degradation of the plurality of pixels; Compensation data of all the pixels stored in the compensation memory is divided into two frame periods and loaded by 1/2 to compensate image data of 1/2 pixels of all pixels in the first frame period, and the remaining 1 / in the second frame period. A time division compensator for compensating image data of two pixels; And a timing controller configured to drive the gate driver and the data driver in a driving mode and a sensing mode, and supply frame data of the frame unit including the compensated image data and the uncompensated image data to the data driver.

Description

Organic light emitting display device and driving method thereof {ORGANIC LIGHT EMITTING DISPLAY 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 method of driving the same, which reduce manufacturing cost by reducing memory for external compensation, and reduce power consumption and heat generation.

Among the flat panel display devices, the organic light emitting display device is attracting attention as a next-generation display device because of the advantages of high response speed, low power consumption, high resolution, and large screen.

The organic light emitting display device is characterized in that the threshold voltage Vth of the driving TFT shifts (deteriorates) because image data (data voltage) is applied to the driving TFT DT for a long time. As a method for compensating for shifting of the threshold voltage Vth of the driving TFT DT, there are an internal compensation method for performing compensation inside the pixel and an external compensation method for compensating outside the pixel.

1 is a circuit diagram illustrating a pixel structure of a conventional organic light emitting display device. 1 illustrates a pixel of an organic light emitting display device that compensates for deterioration of a driving TFT by an external compensation method.

Referring to FIG. 1, each pixel of the display panel includes an organic light emitting diode OLED that emits light by an input data current Ioled, and a pixel circuit PC for driving the organic light emitting diode OLED. . The pixel circuit PC includes a first switching TFT ST1, a second switching TFT ST2, a driving TFT DT, and a capacitor Cst.

The first switching TFT ST1 is switched in accordance with a scan signal (gate driving signal) supplied to the gate line GL. The first switching TFT ST1 is turned on and the data voltage Vdata supplied to the data line DL is supplied to the driving TFT DT.

The driving TFT DT is switched according to the data voltage Vdata supplied from the first switching transistor ST1. The data current Ioled flowing to the organic light emitting diode OLED is controlled by switching of the driving TFT DT.

The capacitor Cst is connected between the gate terminal and the source terminal of the driving TFT DT. The capacitor Cst stores a voltage corresponding to the data voltage Vdata supplied to the gate terminal of the driving TFT DT. The driving TFT DT is turned on using the voltage stored in the capacitor Cst.

The organic light emitting diode OLED is electrically connected between the source terminal of the driving TFT DT and the cathode power supply VSS. The organic light emitting diode OLED emits light by the data current Ioled supplied from the driving TFT DT.

For external compensation, a sensing signal line SL formed in the same direction as the gate line GL is formed. A second switching TFT ST2 is formed to be switched according to the sense signal applied to the sensing signal line SL. The ADC (analog to digital converter) of the drive IC senses the data current Ioled supplied to the organic light emitting diode OLED by switching of the second switching TFT ST2.

In the organic light emitting diode display according to the related art, the size of the data current Ioled flowing from the first driving power supply VDD to the organic light emitting diode OLED is switched by switching the driving TFT DT according to the data voltage Vdata. To control. Through this, an image is displayed by emitting an organic light emitting diode OLED of each pixel.

However, there is a problem in that the threshold voltage Vth / mobility characteristics of the driving TFT DT are different for each pixel according to the nonuniformity of the TFT manufacturing process. As a result, even when the same data voltage Vdata is applied to the driving TFT DT of each pixel, variations in the current flowing through the organic light emitting diode OLED are generated, which makes it impossible to realize uniform image quality.

In addition, when the threshold voltage Vth of the driving TFT DT is shifted and the threshold voltage Vth of the driving TFT DT is shifted beyond a certain range by driving for a long time according to the display of the image, a uniform image quality can be realized. There will be no.

2 is a view for explaining the problem of the external compensation method of the organic light emitting display device according to the prior art.

Referring to FIG. 2, a memory in which compensation data is stored is provided in an organic light emitting display device. In the memory, initial compensation data that compensates for the threshold voltage Vth and mobility characteristics of the driving TFT DT of all the pixels is stored when the product is shipped. In addition, real-time compensation data generated by real-time sensing during driving is reflected in the initial compensation data, and compensation data reflecting the initial compensation data and the real-time compensation data is stored in the memory.

Here, a sensing signal is supplied to one horizontal line among all the lines in a blank section between the frames (when driving at 120 Hz, about 350us) to perform real time sensing in units of one horizontal line, and 1 Real-time compensation data of each pixel may be generated in units of horizontal lines and stored in a memory.

The compensation data stored in the memory is output to be synchronized with the source image data input when the display is driven, and the data voltage corresponding to the compensated image data is supplied to each pixel by reflecting the compensation data to the source image data.

When source image data with Full-HD resolution and 120Hz driving frequency is input, 4 pixels of compensation data (one pixel is composed of RGBW sub-pixel) per clock to synchronize the source image data with the compensation data, and 256bit bandwidth (bandwidth), it should be possible to output the compensation data at the frequency of 80Mhz.

To this end, the memory requires a 32-bit bandwidth and a transmission speed of 640 Mbps, and in the prior art, two DDR2 memories having a 16-bit bandwidth and an 80 MHz frequency are bundled to form a memory for storing and outputting compensation data. .

As described above, the price of the product increases due to the two DDR2 memories, and the power consumption of the memory and the timing controller increases because the two DDR2 memories are driven at high speed. In addition, the number of pins of the timing controller is increased to transmit and receive data between the two DDR2 memories and the timing controller, thereby complicating the design of the driving circuit and increasing the manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an organic light emitting display device and a driving method thereof capable of reducing manufacturing costs by reducing a memory for external compensation.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an organic light emitting display device and a driving method thereof capable of reducing power consumption and heat generation of a memory for external compensation.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above-described problems, and provides an organic light emitting display device capable of simplifying circuit design and reducing manufacturing costs by reducing the number of pins of a timing controller connected to a memory for external compensation. It is a task.

In addition to the technical task of the present invention mentioned above, other features and advantages of the present invention will be described below, or from such description and description will be clearly understood by those skilled in the art.

An organic light emitting display device according to an embodiment of the present invention for achieving the above object is a display panel in which a plurality of pixels are arranged; A gate driver supplying a scan signal and a sensing signal to the plurality of pixels; A data driver supplying a data voltage to the plurality of pixels and sensing characteristics of the plurality of pixels; A compensation memory storing compensation data for compensating for degradation of the plurality of pixels; Compensation data of all the pixels stored in the compensation memory is divided into two frame periods and loaded by 1/2 to compensate image data of 1/2 pixels of all pixels in the first frame period, and the remaining 1 / in the second frame period. A time division compensator for compensating image data of two pixels; And a timing controller configured to drive the gate driver and the data driver in a driving mode and a sensing mode, and supply frame data of the frame unit including the compensated image data and the uncompensated image data to the data driver.

According to an aspect of the present invention, there is provided a driving method of an organic light emitting display device, the method comprising: loading compensation data of 1/2 pixels among compensation data of all pixels in a first frame period; A second step of compensating image data of 1/2 pixels of all pixels by using the compensation data loaded in the first step; A third step of loading compensation data of the remaining 1/2 pixels except the compensation data loaded in the first frame period in a second frame period; And compensating for the image data of the remaining 1/2 pixels of the entire pixels by using the compensation data loaded in the second frame period.

The organic light emitting diode display and the driving method thereof according to an embodiment of the present invention can reduce the manufacturing cost by reducing the memory for external compensation.

The organic light emitting diode display and the driving method thereof according to the embodiment of the present invention can reduce power consumption and heat generation by reducing a memory for external compensation.

The number of pins of the timing controller connected to the memory for external compensation of the organic light emitting display device according to the embodiment of the present invention can simplify the circuit design and reduce the manufacturing cost.

In addition, other features and advantages of the present invention may be newly understood through the embodiments of the present invention.

1 is a circuit diagram illustrating a pixel structure of a conventional organic light emitting display device.
2 is a view for explaining the problem of the external compensation method of the organic light emitting display device according to the prior art.
3 is a schematic view of an organic light emitting display device according to an embodiment of the present invention.
4 is a diagram illustrating a pixel structure, a data driver, a timing controller, and a memory of an organic light emitting display device according to an exemplary embodiment of the present invention.
5 and 6 illustrate a time division compensator and a driving method thereof of an organic light emitting diode display according to an exemplary embodiment of the present invention.
FIG. 7 is a diagram illustrating a luminance conversion lookup table (LUT) of an organic light emitting diode display according to an exemplary embodiment.
8 to 13 illustrate a method of driving an organic light emitting display device according to an exemplary embodiment of the present invention.

In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components have the same number as much as possible even though they are displayed on different drawings.

On the other hand, the meaning of the terms described herein will be understood as follows.

A singular expression should be understood to include a plurality of expressions unless the context clearly indicates otherwise, and the terms "first", "second", and the like are intended to distinguish one component from another. The scope of the rights shall not be limited by these terms.

It is to be understood that the term "comprises" or "having" does not preclude the existence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.

The term "at least one" should be understood to include all combinations which can be presented from one or more related items. For example, the meaning of "at least one of the first item, the second item, and the third item" means two items of the first item, the second item, and the third item, as well as two items of the first item, the second item, and the third item, respectively. A combination of all items that can be presented from more than one.

The organic light emitting display device according to the embodiment of the present invention can reduce the memory for external compensation to reduce the manufacturing cost, power consumption and heat generation. Hereinafter, a preferred embodiment of a method of driving an organic light emitting display device according to the present invention to which an external compensation scheme is applied will be described in detail with reference to the accompanying drawings.

3 is a view schematically illustrating an organic light emitting display device according to an embodiment of the present invention, and FIG. 4 is a view illustrating a pixel structure, a data driver, a timing controller, and a memory of the organic light emitting display device according to an embodiment of the present invention. Drawing.

3 and 4, an organic light emitting display device according to an exemplary embodiment of the present invention includes a display panel 100 and a driving circuit unit.

The display panel 100 includes a plurality of gate lines GL, a plurality of sensing signal lines SL, a plurality of data lines DL, a plurality of driving power lines PL, and a plurality of reference voltage lines RL. The plurality of pixels P are defined by these lines.

The plurality of pixels P includes an organic light emitting diode OLED and a pixel circuit PC for emitting the organic light emitting diode OLED.

The difference voltage Vdata-Vref between the data voltage Vdata and the reference voltage Vref is charged in the capacitor Cst connected between the gate electrode and the source electrode of the driving TFT DT. The driving TFT DT is switched using the charging voltage of the capacitor Cst. The organic light emitting diode OLED emits light by the data current Ioled input via the driving TFT DT.

Each of the plurality of pixels P may be formed of any one of a red pixel, a green pixel, a blue pixel, and a white pixel. One unit pixel displaying an image may include an adjacent red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel. .

The plurality of pixels P is formed in the pixel area defined in the display panel 100. To this end, the display panel 100 includes a plurality of gate lines GL, a plurality of sensing signal lines SL, a plurality of data lines DL, a plurality of driving power lines PL, and a plurality of pixels to define pixel regions. The reference voltage line RL is formed.

The plurality of gate lines GL and the plurality of sensing signal lines SL may be formed in the first direction (eg, in a horizontal direction) in the display panel 100. In this case, a scan signal (gate driving signal) is applied from the gate driver 300 to the gate line GL. In addition, a sensing signal sense is applied from the gate driver 300 to the sensing signal line SL.

The plurality of data lines DL may be formed in a second direction (eg, a vertical direction) to intersect the plurality of gate lines GL and the plurality of sensing signal lines SL. In this case, the data line DL is supplied with the data voltage Vdata from the data driver 200 of the driving circuit unit. The data voltage Vdata has a voltage level to which a compensation voltage corresponding to the shift of the threshold voltage Vth of the driving TFT DT of the pixel P is added. The compensated image data generated by reflecting the compensation data in the compensation data and the source data generated by sensing the pixels will be described later.

The plurality of reference voltage lines RL are formed in parallel with each of the plurality of data lines DL. The display reference voltage Vpre_r or the sensing precharging voltage Vpre_s may be selectively supplied to the reference voltage line RL from the data driver 200.

The display reference voltage Vpre_r is supplied to each reference voltage line RL during the data charging period of each pixel P. The sensing precharging voltage Vpre_s may be supplied to the reference voltage line RL during a sensing period in which the threshold voltage / mobility of the driving TFT DT of each pixel P is sensed.

The plurality of driving power lines PL may be formed to be parallel to the gate line GL. The first driving power source VDD is supplied to the pixel P through the driving power line Pl.

The pixel circuit PC of each pixel P includes a first switching TFT ST1, a second switching TFT ST2, the driving TFT DT, and a capacitor Cst. Here, the TFTs ST1, ST2, and DT may be N-type TFTs, and may be a-Si TFTs, poly-Si TFTs, oxide TFTs, organic TFTs, or the like. However, the present invention is not limited thereto, and the TFTs ST1, ST2, and DT may be a-Si TFT, poly-Si TFT, Oxide TFT, Organic TFT, or the like as a P-type TFT.

The gate electrode of the first switching TFT ST1 is connected to the gate line GL, the source electrode (first electrode) is connected to the data line DL, and the drain electrode (second electrode) is the driving TFT ( It is connected to the 1st node n1 connected with the gate electrode of DT.

The first switching TFT ST1 is turned on according to a scan signal of a gate-on voltage level supplied to the gate line GL. When the first switching TFT ST1 is turned on, the data voltage Vdata supplied to the data line DL is supplied to the gate electrode of the first node n1, that is, the driving TFT DT.

The gate electrode of the second switching TFT ST2 is connected to the sensing signal line SL, the source electrode (first electrode) is connected to the reference voltage line RL, and the drain electrode is connected to the driving TFT DT. The organic light emitting diode OLED is connected to the second node n2 connected thereto.

The second switching TFT ST2 is turned on according to a sensing signal sense of a gate-on voltage level supplied to the sensing signal line SL. When the second switching TFT ST2 is turned on, the display reference voltage Vpre_r or the sensing precharging voltage Vpre_s supplied to the reference voltage line RL is supplied to the second node n2.

The capacitor Cst is connected between the gate electrode and the source electrode of the driving TFT DT. That is, the first electrode of the capacitor Cst is connected to the first node n1, and the second electrode of the capacitor Cst is connected between the second node n2. The capacitor Cst charges the difference voltage between the voltages supplied to each of the first node n1 and the second node n2, and then switches the driving TFT DT according to the charged voltage.

The gate electrode of the driving TFT DT is connected in common to the drain electrode of the first switching TFT ST1 and the first electrode of the capacitor Cst. The drain electrode of the driving TFT DT is connected to the driving power supply line PL. The source electrode of the driving TFT DT is connected to the second node. That is, the source electrode of the driving TFT DT is commonly connected to the drain electrode of the second switching TFT ST2, the second electrode of the capacitor Cst, and the anode of the organic light emitting diode OLED.

The driving TFT DT is turned on by the voltage charged in the capacitor Cst for each light emission period, thereby controlling the amount of current flowing from the first driving power supply VDD to the organic light emitting diode OLED.

The organic light emitting diode OLED emits light by the data current Ioled supplied from the driving TFT DT of the pixel circuit PC to emit monochromatic light having a luminance corresponding to the data current Ioled. To this end, the organic light emitting diode OLED may be formed on an anode electrode (not shown) connected to the second node n2 of the pixel circuit PC, an organic layer (not shown) formed on the anode electrode, and formed on the organic layer. And a cathode electrode (not shown) to which the second driving power source VSS is supplied.

The driving circuit unit includes a data driver 200, a gate driver 300, a timing controller 400, a time division compensation unit 410, and a compensation memory 500.

The timing controller 400 displays the input image by operating the data driver 200 and the gate driver 300 in a driving mode based on the timing synchronization signal TSS. In addition, the data driver 200 and the gate driver 300 are operated in the sensing mode to sense the threshold voltage / mobility of the driving TFT DT of each pixel.

To this end, the timing controller 400 generates a data control signal DCS and a gate control signal GCS based on the timing synchronization signal TSS. The data driver 200 and the gate driver 300 operate in a driving mode or a sensing mode by using the data control signal DCS and the gate control signal GCS. The timing synchronization signal TSS may be a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable DE, a clock DCLK, and the like.

The gate control signal GCS for controlling the gate driver 300 may include a gate start signal and a plurality of clock signals. The data control signal DCS for controlling the data driver 200 may include a data start signal, a data shift signal, and a data output signal.

The gate driver 300 operates in the driving mode and the sensing mode according to the mode control of the timing controller 400. The gate driver 300 is connected to the plurality of gate lines GL and the plurality of sensing signal lines SL. The gate driver 300 is formed in the form of an integrated circuit (IC) and connected to the display panel 100 through a flexible cable, or the substrate of the display panel 100 together with the transistor forming process of each pixel P. It may also be formed directly on.

In the driving mode, the gate driver 300 generates a scan signal having a gate-on voltage level every one horizontal period according to the gate control signal GCS supplied from the timing controller 400. The gate driver 300 sequentially supplies the generated scan signal scan to the plurality of gate lines GL.

In addition, the gate driver 300 is connected to each of the plurality of driving power lines PL1 to PLm and supplies driving power VDD supplied from an external power supply unit (not shown) to the plurality of driving power lines PL1 to PLm. Supply.

The scan signal scan has a gate-on voltage level during the data charging period of each pixel P. The scan signal scan has a gate-off voltage level during the light emission period of each pixel P. FIG. The gate driver 300 may be a shift register that sequentially outputs a scan signal scan.

In addition, in the sensing mode, the gate driver 300 generates a sense signal having a gate-on voltage level for each of an initialization period and a detection voltage charging period of each pixel P. The sensing signal is sequentially supplied to the plurality of sensing signal lines SL.

For example, the pixel may be sensed in units of one horizontal line, and in the sensing mode, the gate driver 300 sequentially supplies a sense signal for each horizontal line from the top to the bottom. Through this, the entire horizontal line is sequentially sensed one line from the top down.

As shown in FIGS. 3 and 4, the data driver 200 is connected to the plurality of data lines DL1 to DLn, and operates in a display mode and a sensing mode according to mode control of the timing controller 400.

The driving mode for displaying an image can be driven in a data charging period in which each pixel is charged with a data voltage and in a light emission period in which the organic light emitting diode OLED emits light. The sensing mode may be driven by an initialization period for initializing each pixel, a sensing voltage charging period, and a sensing period.

The data driver 200 includes a data voltage generator 210 and a switch 220.

The data voltage generator 210 converts the input image data into a data voltage Vdata and supplies the data voltage to the data line DL. In this case, the initial compensation data and the real-time compensation data are reflected, and the image data compensated by the compensation data stored in the compensation memory 500 is supplied to the data voltage generator 210. The compensated image data of one frame does not include a compensation value of source image data of all pixels. The source image data of pixels corresponding to 1/2 of all the pixels is compensated and input, and the source image data of pixels corresponding to 1/2 is input without compensation.

The data voltage generator 210 includes a shift register, a latch unit, a gray voltage generator, a digital-to-analog converter (DAT), and an output unit.

The shift register generates a sampling signal, and the latch unit latches the pixel data according to the sampling signal. The gray voltage generator generates a plurality of gray voltages using the plurality of reference gamma voltages, and the digital-to-analog converter DAC converts the gray voltages corresponding to the pixel data latched among the plurality of gray voltages to the data voltage Vdata. Select with) to print. The output unit outputs the data voltage Vdata.

The switching unit 220 includes a plurality of first switches 222 and a plurality of second switches 224.

In the driving mode, the plurality of first switches 222 switch the data voltage Vdata or the reference voltage Vpre_d to supply the data line DL.

In the sensing mode, the plurality of second switches 224 switch the display reference voltage Vpre_r or the sensing precharging voltage Vpre_s to supply the reference voltage line RL. The reference voltage line RL supplied with the sensing precharging voltage Vpre_s is floated through the second switch 224. Thereafter, the reference voltage line RL is connected to the sensing data generator 420 to sense the corresponding pixel.

For example, in a driving mode in which an image is displayed, the image is displayed by supplying a data voltage Vdata according to the image data from the first data line to the last data line during a period of N frames. In this case, the display reference voltage Vpre_r is supplied to the reference power line RL.

A plurality of second switches 224 are switched in a blank period between n frames and n + 1 frames to supply sensing precharging voltage Vpre_s to one reference power line RL or a plurality of reference power lines RL. do. For example, the sensing precharging voltage Vpre_s may be supplied at −1V to + 1V.

Thereafter, the reference voltage line RL is floated through the second switch 224. Thereafter, the reference voltage line RL is connected to the sensing data generator 420 to sense the corresponding pixel. In this case, the voltage sensed from the reference voltage line RL may be determined as a ratio of the current flowing in the driving TFT DT and the capacitance of the reference voltage line RL according to a time change. The sensing data includes data corresponding to the threshold voltage / mobility of the driving TFT DT of each pixel P.

Thereafter, the sensing data of each pixel is converted into real-time compensation data by the sensing data generator 420, and the real-time compensation data is reflected in the initial compensation data stored in the compensation memory 500.

The compensation memory 500 stores compensation data of all pixels (one pixel is composed of four sub-pixels RGBW). Here, the compensation data is the real-time compensation data is reflected in the initial compensation data.

The initial compensation data is generated and stored in the compensation memory 500 before the product is released in order to compensate for characteristic variations in the threshold voltage Vth and mobility of the driving TFT DT formed in all the pixels. The initial compensation data is generated by sensing the characteristic variation of the threshold voltage Vth and the mobility of the driving TFT DT formed in all the pixels after the display panel is manufactured and before the product is shipped. The initial compensation data is stored in the compensation memory 500 before shipping.

The real-time compensation data is generated by sensing a characteristic change of the driving TFT formed in all pixels in real time while the organic light emitting display device is driven. The compensation data is continuously updated by reflecting real-time compensation data generated by sensing pixels in real time in the initial compensation data stored in the compensation memory 500.

The organic light emitting display device of the present invention does not compensate source image data of all pixels, compensates image data of 1/2 pixels among all pixels in a first frame period, and images of remaining 1/2 pixels in a second frame period. Compensate your data. In this way, the compensation data of all pixels stored in the compensation memory 500 are loaded in half by dividing the data into two frame periods, and the source image data is compensated based on the compensation data of the loaded 1/2 pixels.

When source image data with Full-HD resolution and 120Hz driving frequency is input, 4 pixels of compensation data (one pixel is composed of RGBW sub-pixel) per clock to synchronize the source image data with the compensation data, and 256bit bandwidth (bandwidth), it should be possible to output the compensation data at the frequency of 80Mhz.

In the prior art, in order to output the compensation data at the 256-bit bandwidth and the 80-MHz frequency, the 16-bit bandwidth and the DDR2 memory are bundled to output the compensation data at the 320-MHz frequency (640 Mbps) at the 32-bit bandwidth.

On the other hand, the compensation memory 500 of the organic light emitting display device of the present invention is composed of one DDR2 memory having a 16-bit bandwidth and 320Mhz (640Mbps) frequency. Therefore, the DDR2 memory for configuring the compensation memory 500 may be reduced to 1/2 to reduce manufacturing costs, and power consumption required for driving the compensation memory 500 and the timing controller 400 may be reduced.

Referring back to FIG. 4, the timing controller 400 generates real-time compensation data, stores the compensation data in the compensation memory 500, and compensates the source image data with the compensation data stored in the compensation memory 500. To this end, the timing controller 400 includes a time division compensator 410 and a sensing data generator 420.

The sensing data generator 420 converts the sensing data (analog voltage) generated by sensing the voltage charged in the reference voltage line RL and converts the real-time compensation data in a digital form into the memory 500. In this case, the voltage sensed from the reference voltage line RL may be determined as a ratio of the current flowing in the driving TFT DT and the capacitance of the reference voltage line RL according to a time change. The sensing data includes data corresponding to the threshold voltage / mobility of the driving TFT DT of each pixel P.

The time division compensation unit 410 reflects the compensation data in the source image data so that the compensated image data is supplied to the data driver 200. The compensation of the image data is performed by applying the loaded compensation data to the source image data of 1/2 of the pixels in which the compensation data is loaded among all the pixels. In this case, compensation data is not applied to the source image data every frame for each pixel, and compensation data is applied to the source image data every two frames so that the compensation value of the compensation data is doubled to be reflected in the source image data.

5 and 6 illustrate a time division compensator and a driving method thereof of an organic light emitting diode display according to an exemplary embodiment of the present invention.

5 and 6, the time division compensation unit 410 loads the compensation data of all pixels stored in the compensation memory 500 by dividing them into two frame periods by 1/2. At this time, in the first frame period, compensation data of 1/2 pixels among the compensation data of all pixels is loaded to compensate for image data of 1/2 pixels of all pixels.

In the second frame period, even the compensation data of 1/2 pixels of the compensation data of all pixels is loaded to compensate for the image data of the remaining 1/2 pixels. That is, all pixels are compensated in a time division manner, and image data of pixels corresponding to 1/2 of all pixels is compensated in one frame period.

To this end, the time division compensation unit 410 includes a selection unit 412, a luminance conversion lookup table 414, a compensation unit 416, and an output unit 418.

The selector 410 determines whether to compensate the source image data of the odd pixels or the source image data of the even pixels among the source image data input to the timing controller 400 according to the odd / even pixel selection signal input from the timing controller 400. Choose.

FIG. 7 is a diagram illustrating a luminance conversion lookup table (LUT) of an organic light emitting diode display according to an exemplary embodiment.

6 and 7, the compensation unit 416 loads compensation data of odd pixels or even pixels to be compensated according to an odd / even pixel selection signal from the compensation memory 500.

When the odd pixel selection signal is input, the image data is compensated by reflecting the compensation data of the odd pixels in the source image data of the odd pixels among the source image data of all pixels, and the source image data of the odd pixels is not compensated.

On the contrary, when the even pixel selection signal is input, the image data is compensated by reflecting the compensation data of the even pixels in the source image data of the even pixels among the source image data of all pixels, and the source image data of the odd pixels is not compensated.

The compensator 416 calculates a voltage V corresponding to the gray of the compensation data of the odd or even pixels using the luminance conversion lookup table 414 shown in FIG. 7. The compensation luminance L value is calculated according to the voltage value. The compensation voltage value Vth_L × 2_V corresponding to twice the compensation luminance Vth_L × 2 of the calculated compensation luminance value is calculated.

Thereafter, the compensation data corresponding to the compensation voltage value is reflected in the source image data, and the compensated image data is output through the output unit 418. In this case, the compensated data is reflected in the source image data of 1/2 selected pixels among the source image data of all pixels, and the compensated image data is output. The source image data of the other half pixels not selected is output as it is without compensation.

As an example, in the first frame period, compensation data of odd pixels among all pixels is loaded from the compensation memory 500. The image data is compensated by applying compensation data of the odd pixels loaded from the compensation memory 500 to the source image data of the odd pixels among the source image data of all pixels.

On the other hand, compensation data of even pixels among all the pixels in the first frame period is not loaded in the compensation memory 500. The source image data of the even pixels of the source image data of all pixels is output without being compensated.

Subsequently, in the second frame period, compensation data of even pixels among all the pixels is loaded in the compensation memory 500. The image data is compensated by applying compensation data of the even pixels loaded from the compensation memory 500 to the source image data of the even pixels among the source image data of all pixels.

On the other hand, compensation data of odd pixels among all the pixels in the second frame period are not loaded in the compensation memory 500. The source image data of the odd pixels is output as it is without compensating among the source image data of all pixels.

As such, when the compensated image data is output, the compensation data Vth_L × 2_V is generated with the luminance Vth_L × 2 corresponding to twice the compensation luminance calculated for 1/2 of the pixels. When the generated compensation data is reflected in the source image data, the average brightness perceived by the viewer's eyes in two frame periods becomes equal to the brightness Vth_L corresponding to the compensation data loaded from the compensation memory 500.

Accordingly, the time division compensation unit 410 of the present invention loads compensation data of pixels corresponding to one-half of all pixels from the compensation memory 500, thereby reducing the bandwidth of the compensation memory 500 compared to the prior art. Can be reduced to / 2. That is, even when the compensation memory 500 outputs compensation data of pixels corresponding to 1/2 of all pixels with a bandwidth of 256 bits and a frequency of 40 MHz, compensation driving can be performed without loss of the compensation data.

According to an embodiment of the present disclosure, a method of driving an organic light emitting display device includes: a first step of loading compensation data of 1/2 pixels among compensation data of all pixels in a first frame period, and the compensation loaded in the first step A second step of compensating image data of 1/2 pixels among all pixels using data, and loading compensation data of the remaining 1/2 pixels in the second frame period except the compensation data loaded in the first frame period And compensating the image data using the third step and a fourth step of compensating the image data of the remaining half of the pixels using the compensation data loaded in the second frame period.

8 to 13 illustrate a method of driving an organic light emitting display device according to an exemplary embodiment of the present invention. Hereinafter, exemplary embodiments of a method of driving an organic light emitting display device according to the present invention will be described with reference to FIGS. 8 to 13.

<Method of Driving Compensation in the First Frame Period>

Referring to FIG. 8, when source image data of the first frame is input, a pixel to be compensated is selected from all pixels (S10). In FIG. 8, it is assumed that odd pixels are selected among all pixels as pixels to which image data compensation is to be applied.

Thereafter, among the input source image data, image data to which compensation data is applied is distinguished. That is, the source image data of the odd pixels and the source image data of the even pixels are distinguished (S11).

Subsequently, since the application of the compensation data is not selected, the source image data of the even pixels is output as it is (even_Vdata) without compensation (S12).

Meanwhile, since the application of the compensation data is selected for the source image data of the odd pixels, the compensation data of the odd pixels is loaded from the compensation data of all the pixels stored in the compensation memory 500 (S13). In this case, compensation data of even pixels stored in the compensation memory 500 is not loaded in order to reduce the bandwidth of the compensation memory 500 and the number of DDR2 memories.

Subsequently, a voltage V value corresponding to gray of the source image data of the odd pixels is calculated using the luminance conversion lookup table 414 illustrated in FIG. 7. The luminance value according to the voltage value of the source image data of the odd pixels is calculated. In addition, a voltage V value Vdata corresponding to the gray of the compensation data of the odd pixels is calculated. The luminance value Vdata + Vth corresponding to the voltage value of the compensation data of the odd pixels is calculated (S14).

Subsequently, a difference between the luminance value Vdata + Vth of the compensation data of the odd pixels and the luminance value Vdata of the source image data of the odd pixels is obtained to calculate a compensation luminance Vth_L of the odd pixels (S15).

Thereafter, the output luminance Vdata'_L of the odd pixels is calculated by multiplying the calculated compensation luminance value by 2 times (S16).

Thereafter, a compensation voltage value Vth_L × 2_V corresponding to an output luminance that is twice the compensation luminance value is calculated (S17).

Thereafter, compensation data corresponding to the compensation voltage value Vth_L × 2_V is output as compensation data of source image data of the odd pixels (S18).

Thereafter, the compensation data of the odd pixel is reflected in the source image data of the odd pixel to compensate for the image data of the odd pixel (S19).

Thereafter, one frame of compensated image data is composed of the compensated odd pixel image data and the uncompensated even pixel image data, and the compensated image data of one frame is supplied to the data driver 200.

Referring to FIG. 10, when the compensation data of the odd pixels is loaded from the compensation memory 500 in the first frame period, and the source image data of the odd pixels is compensated with a luminance value that is twice the compensation luminance of the compensation data, compensation is performed. The bandwidth of the memory 500 may be reduced by 1/2 compared to the related art.

In addition, when the odd pixels are compensated with a luminance value Vth_L × 2 that is twice the compensation luminance according to the compensation data of the odd pixels loaded from the compensation memory 500, the average brightness perceived by the viewer's eyes in two frame periods. Is equal to the luminance Vth_L corresponding to the compensation data loaded from the compensation memory 500.

Therefore, even when the compensation data of the odd pixels corresponding to 1/2 of the entire pixels are output at a frequency in the compensation memory 500 with a bandwidth of 1/2 compared to the prior art, the compensation driving is performed without loss of the compensation data. Can be.

<Compensation Driving Method in Second Frame Period>

9, when source image data of the second frame is input, a pixel to be compensated is selected from all pixels (S20). In FIG. 9, it is assumed that even pixels are selected among all pixels as pixels to which image data compensation is to be applied.

Thereafter, among the input source image data, image data to which compensation data is applied is distinguished. That is, the source image data of the odd pixels and the source image data of the even pixels are distinguished (S21).

Thereafter, since the application of the compensation data is not selected, the source image data of the odd pixels is output as it is without compensation (odd_Vdata) (S22).

Meanwhile, since the application of the compensation data is selected for the source image data of the even pixels, the compensation data of the even pixels is loaded from the compensation data of all pixels stored in the compensation memory 500 (S23). In this case, in order to reduce the bandwidth of the compensation memory 500 and the number of DDR2 memories, compensation data of the odd pixels stored in the compensation memory 500 is not loaded.

Subsequently, a voltage V value corresponding to gray of the source image data of the even pixels is calculated using the luminance conversion lookup table 414 illustrated in FIG. 7. The luminance value is calculated according to the voltage value of the source image data of the even pixels. In addition, a voltage V value Vdata corresponding to gray of the compensation data of the even pixels is calculated. The luminance value Vdata + Vth corresponding to the voltage value of the compensation data of the even pixels is calculated (S24).

Thereafter, a difference between the luminance value Vdata + Vth of the compensation data of the even pixels and the luminance value Vdata of the source image data of the even pixels is obtained to calculate a compensation luminance VTH_L value of the even pixels (S25).

Thereafter, the output luminance Vdata'L of the even pixels is calculated by multiplying the calculated compensation luminance value by two times (S26).

Subsequently, a compensation voltage value Vth_L × 2_V corresponding to an output luminance that is twice the compensation luminance value is calculated (S27).

Thereafter, compensation data corresponding to the compensation voltage value Vth_L × 2_V is output as compensation data of source image data of the even pixels (S28).

Thereafter, the compensation data of the even pixel is reflected in the source image data of the even pixel to compensate for the image data of the even pixel (S29).

Thereafter, one frame of compensated image data is composed of the image data of the compensated even pixel and the image data of the uncompensated odd pixel, and the compensated image data of one frame is supplied to the data driver 200.

Referring to FIG. 11, when the compensation data of the even pixels is loaded from the compensation memory 500 in the second frame period, and the source image data of the even pixels is compensated with a luminance value that is twice the compensation luminance of the compensation data, compensation is performed. The bandwidth of the memory 500 may be reduced by 1/2 compared to the related art.

In addition, if the even pixels are compensated with a luminance Vth_L × 2 value corresponding to twice the compensation luminance according to the compensation data of the even pixels loaded from the compensation memory 500, the average brightness perceived by the viewer's eyes in two frame periods. Is equal to the luminance Vth_L corresponding to the compensation data loaded from the compensation memory 500.

Therefore, even when outputting compensation data of even pixels corresponding to one-half of all pixels at a frequency in the compensation memory 500 with a bandwidth of 1/2 compared to the prior art, compensation driving is performed without loss of compensation data. Can be.

As another embodiment of the method of driving the organic light emitting display device, referring to FIGS. 12 and 13, image data of 1/2 pixels of all pixels is compensated in the first frame period, and the remaining 1 in the second frame period. Compensate image data of the / 2 pixels. In this way, the compensation data of all pixels stored in the compensation memory 500 are loaded in half by dividing the data into two frame periods, and the source image data is compensated based on the compensation data of the loaded 1/2 pixels.

<Compensation driving method of first frame period  >

As illustrated in FIG. 12, in the first frame period, compensation data of odd pixels is not loaded from the compensation memory 500 among compensation pixels 500 among pixels arranged in the first horizontal line. Load from. Compensating the source image data of the odd pixels based on the compensation data of the odd pixels loaded in the compensation memory 5000. In this case, the method described above with reference to FIGS. Compensation data used for compensation may be generated.

Subsequently, the compensation data of the odd pixels among the pixels arranged on the second horizontal line is loaded from the compensation memory 500 without loading the compensation data of the even pixels in the compensation memory 500 to compensate for the source image data of the even pixels. do. In this case, compensation data used for compensation of the source image data of the even pixels may be generated by applying the same method described above with reference to FIGS. 5 to 11.

As described above, in the first frame period, the source image data of all pixels among the pixels arranged in the odd horizontal line is compensated, and the source image data of the even pixels is not compensated. Further, the source image data of the even pixels is compensated among the appeals arranged in the even horizontal line, and the source image data of the odd pixels is not compensated.

<Compensation Driving Method in Second Frame Period>

As shown in FIG. 13, in the second frame period, the compensation data of the odd pixels among the pixels arranged in the first horizontal line are not loaded in the compensation memory 500, and the compensation data of the even pixels is compensated in the compensation memory 500. To load). Compensating the source image data of the even pixels based on the compensation data of the even pixels loaded in the compensation memory 5000. In this case, the method described above with reference to FIGS. Compensation data used for compensation may be generated.

Subsequently, the compensation data of the even pixels among the pixels arranged on the second horizontal line is loaded from the compensation memory 500 without loading the compensation data of the odd pixels in the compensation memory 500, thereby compensating the source image data of the odd pixels. do. In this case, compensation data used for compensation of the source image data of the even pixels may be generated by applying the same method described above with reference to FIGS. 5 to 11.

As described above, in the second frame period, the source image data of all the pixels among the pixels arranged in the odd horizontal line is compensated, and the source image data of the even pixels is not compensated. Further, the source image data of the even pixels is compensated among the appeals arranged in the even horizontal line, and the source image data of the odd pixels is not compensated.

As shown in FIGS. 12 and 13, when the source image data of the odd pixels and the source image data of the even pixels are compensated in a lattice pattern, the average luminance perceived by the viewer's eyes in the two frame period is measured in the compensation memory 500. It becomes equal to the luminance Vth_L corresponding to the loaded compensation data.

In addition, by alternately performing compensation of the odd pixels and the even pixels on a frame basis, flicker may be prevented due to the luminance difference between the pixels to which compensation is applied and the pixels to which compensation is not applied.

Therefore, even when the compensation data of the pixels corresponding to one-half of the entire pixels at the frequency in the compensation memory 500 with a bandwidth of 1/2 compared to the prior art, the compensation driving can be performed without loss of the compensation data. have.

In the above description, it has been described that the compensation data Vth_L2_V is generated by applying the luminance Vth_L2 corresponding to twice the compensation luminance value calculated for 1/2 of the pixels. One of the embodiments has been described. The compensation data Vth_L × 2_V may be generated by setting an offset value of a ratio relative to the compensation luminance. In this case, the offset value has a larger value than the compensation luminance value.

Those skilled in the art to which the present invention pertains will understand that the above-described 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 detailed 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: display panel 200: data driver
300: gate driver 400: timing controller
410: time division compensation unit 420: sensing data generation unit
500: memory

Claims (14)

A display panel in which a plurality of pixels are arranged;
A gate driver supplying a scan signal and a sensing signal to the plurality of pixels;
A data driver supplying a data voltage to the plurality of pixels and sensing characteristics of the plurality of pixels;
A compensation memory storing compensation data for compensating for degradation of the plurality of pixels;
The compensation data of all the pixels stored in the compensation memory are divided into two frame periods and loaded by 1/2 so that the image data of 1/2 pixels of all pixels in the first frame period is reflected to the compensation data stored in the compensation memory. After the compensation, the compensated luminance value is compensated to have twice the luminance value, and the image data of the remaining 1/2 pixels is compensated by reflecting the compensation data stored in the compensation memory in the second frame period, and then compensated. A time division compensation unit for compensating for the luminance value to have twice the luminance value; And
And a timing controller configured to drive the gate driver and the data driver in a driving mode and a sensing mode, and supply image data in a frame unit including compensated image data and uncompensated image data to the data driver. An organic light emitting display device. According to claim 1,
The time division compensation unit in one frame period,
And compensate for the compensation data loaded from the compensation memory in the source image data of 1/2 pixels among all pixels, and output the source image data of the remaining 1/2 pixels without compensating them. According to claim 1,
The time division compensation unit is arranged in a first frame period.
And compensating and outputting image data of the odd pixels among all the pixels by loading compensation data of the odd pixels in the compensation memory, and outputting the image data of the even pixels without compensating them. According to claim 1,
The time division compensation unit is arranged in a second frame period,
And compensating and outputting image data of the even pixels among all the pixels by loading compensation data of the even pixels in the compensation memory, and outputting the image data of the odd pixels without compensating them. According to claim 1,
The time division compensation unit is arranged in a first frame period.
Compensating the image data of the odd pixels among the pixels arranged in the odd horizontal line by loading only the compensation data of the odd pixels among the pixels arranged in the odd horizontal line in the compensation memory,
And only the compensation data of the even pixels among the pixels arranged in the even horizontal line is loaded from the compensation memory to compensate for the image data of the even pixels among the pixels arranged in the even horizontal line. According to claim 1,
The time division compensation unit is arranged in a second frame period,
Compensating the image data of the even pixels among the pixels arranged in the odd horizontal line by loading only the compensation data of the even pixels among the pixels arranged in the odd horizontal line,
And only compensation data of odd pixels among pixels arranged in an even horizontal line is loaded from the compensation memory to compensate image data of odd pixels among pixels arranged in an even horizontal line. According to claim 1,
The time division compensation unit,
Calculating a compensation luminance value to a voltage value corresponding to gray of the compensation data loaded from the compensation memory,
Calculating a compensation voltage value corresponding to a luminance value twice the compensation luminance value,
And generating compensation data corresponding to the compensation voltage value to compensate for image data of 1/2 of all pixels. Loading compensation data of 1/2 pixels among compensation data of all pixels in a first frame period;
A second step of compensating image data of 1/2 pixels of all pixels by using the compensation data loaded in the first step, and then compensating the compensated luminance value to have a luminance value of 2 times;
A third step of loading compensation data of the remaining 1/2 pixels except the compensation data loaded in the first frame period in a second frame period; And
A fourth step of compensating for the image data of the remaining 1/2 pixels among all the pixels by using the compensation data loaded in the second frame period, and then compensating the compensated luminance value to have a luminance value of 2 times; A method of driving an organic light emitting display device, characterized in that. The method of claim 8,
And compensates by reflecting the compensation data loaded from the compensation memory to the source image data of 1/2 pixels of all pixels in one frame period, and outputs the source image data of the remaining 1/2 pixels without compensation. A method of driving a light emitting display device. The method of claim 8,
In the first frame period,
Load compensation data of the odd pixels from the compensation memory to compensate and output image data of the odd pixels among all pixels,
The image data of the even pixels are output without compensating. The method of claim 8,
In the second frame period,
Loading compensation data of the even pixels in the compensation memory to compensate and output image data of the even pixels among all pixels,
The image data of the odd pixels is output without compensating the driving method of the organic light emitting display device. The method of claim 8,
In the first frame period,
Compensating the image data of the odd pixels among the pixels arranged in the odd horizontal line by loading only the compensation data of the odd pixels among the pixels arranged in the odd horizontal line,
A method of driving an organic light emitting display device, characterized by compensating image data of even pixels among pixels arranged in an even horizontal line by loading only compensation data of even pixels among pixels arranged in an even horizontal line. The method of claim 8,
In the second frame period,
Compensating the image data of the even pixels among the pixels arranged in the odd horizontal line by loading only the compensation data of the even pixels among the pixels arranged in the odd horizontal line,
And only the compensation data of the odd pixels among the pixels arranged in the even horizontal line is loaded from the compensation memory to compensate for the image data of the odd pixels among the pixels arranged in the even horizontal line. The method of claim 8,
Compensation luminance value is calculated to a voltage value corresponding to gray of the compensation data loaded from the compensation memory,
Calculating a compensation voltage value corresponding to a luminance value twice the compensation luminance value,
And generating compensation data corresponding to the compensation voltage value to compensate for image data of 1/2 of all pixels.

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