KR102470373B1 - Organic light emitting display device - Google Patents

Abstract

An object of the present invention is to perform external compensation using a sensing value received from a randomly selected horizontal line, to start a blanking time at a point immediately before addressing for sensing, and to set three horizontal lines according to the sensing horizontal line. An organic light emitting display device that converts input image data into sensing region compensation image data using sensing region compensation values corresponding to N regions. To this end, the organic light emitting display device according to the present invention includes a panel, a sensing unit, a control unit, a data driver, and a gate driver. The sensing unit collects sensing data by performing sensing for external compensation on a randomly selected horizontal line among the horizontal lines. The control unit determines a characteristic change of each subpixel using the sensing data, calculates an external compensation value, and uses sensing area compensation values corresponding to areas set along the horizontal line where the sensing is performed to input Image data is converted into sensing area compensation image data. The data driver outputs a sensing area compensation data voltage corresponding to the sensing area compensation image data to a data line formed in the panel. The gate driver sequentially outputs gate pulses to gate lines provided in the panel. The sensing region compensation value is different for each region.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device capable of performing external compensation through a sensing line.

Flat Panel Display Devices (FPDs) are used in various types of electronic products, including mobile phones, tablet PCs, and laptop computers. Flat panel displays include Liquid Crystal Display Device (LCD), Plasma Display Panel Device (PDP), and Organic Light-Emitting Diode Display Device (OLED). An electrophoretic display device (EPD) is also widely used.

Of these, the organic light emitting display device (OLED) uses a self-emitting element that emits light by itself, and thus has advantages such as fast response speed, high luminous efficiency, high luminance, and large viewing angle.

An organic light emitting display device is a self-luminous device that displays an image by emitting light from an organic light emitting diode using recombination of electrons and holes. have an angle of view Accordingly, the organic light emitting display device is attracting attention as a next-generation flat panel display device.

However, in a conventional organic light emitting display device, characteristic variations such as a threshold voltage (Vth) and mobility of a driving transistor occur for each pixel due to process variation, deterioration, and the like. Therefore, the amount of current driving each organic light emitting diode is different, and as a result, a luminance deviation occurs between pixels.

In order to solve the above problem, Korean Patent Laid-open Publication No. 10-2013-0066449 (hereinafter referred to as "prior art document") compensates for the characteristic change of the driving transistor included in each pixel through correction of input image data. An external compensation method is disclosed.

1 is an exemplary diagram illustrating a driving method of an organic light emitting display panel proposed in the development stage of the present invention. In FIG. 1 , the vertical axis represents upper and lower portions of the organic light emitting display panel. Accordingly, FIG. 1 shows an organic light emitting display panel having 2160 horizontal lines. In Fig. 1, the horizontal axis represents time. Assuming that one frame period is 8.3 ms, Fig. 1 shows three frame periods.

Conventionally, an external compensation value is generated by sensing the mobility or threshold voltage of each pixel included in one horizontal line during blanking time between frames during driving of the organic light emitting display device. This method is referred to as a high-speed sensing method during driving.

However, when the above-described high-speed sensing method during driving is used, a luminance difference may occur between the lines because the points at which the light is emitted again after the blanking time are different according to the horizontal lines. To solve this problem, a method of changing the blanking time to a point in time just before addressing for sensing has been proposed. This method is referred to as a progressive sensing method.

However, when the progressive sensing method is used, since the horizontal lines are sequentially changed, a phenomenon in which the horizontal lines are visible to the user's eyes may occur. To solve this problem, a random progressive sensing method as shown in FIG. 1 has been proposed.

In an organic light emitting display device using a random progressive sensing method, as shown in FIG. 1 , blanking time starts immediately before addressing for sensing, and horizontal lines may be randomly changed.

In an organic light emitting display device using a random progressive sensing method, three regions may be generated as shown in FIG. 1 .

The first area (a) represents an area disposed above the horizontal line where sensing is performed in the current frame period and disposed above the horizontal line where sensing is performed in the next frame period.

The second area (b) represents an area disposed below the horizontal line where sensing is performed in the current frame period and disposed above the horizontal line where sensing is performed in the next frame period.

The third area (c) represents an area disposed above the horizontal line where sensing is performed in the current frame period and disposed below the horizontal line where sensing is performed in the next frame period.

In addition, there may be an area disposed below the horizontal line where sensing is performed in the current frame period and disposed below the horizontal line where sensing is performed in the next frame period. The characteristics of the region are the same as those of the first region (a).

As described above, the emission maintenance period is different in the three regions a, b, and c. For example, in FIG. 1, pixels included in the third region (c) have the longest emission duration, pixels in the first region (a) have the next longest emission duration, and second region (b) ) has the shortest emission maintenance period of the pixels included in .

A difference in luminance between the regions may occur due to the difference in the emission maintenance period as described above.

An object of the present invention proposed to solve the above problems is to perform external compensation using a sensing value received from a randomly selected horizontal line, start a blanking time at the point immediately before addressing for sensing, and An organic light emitting display device that converts input image data into sensing area compensation image data using sensing area compensation values corresponding to three areas set along the horizontal line formed by the above.

An organic light emitting display device according to the present invention for achieving the above technical problem includes a panel, a sensing unit, a control unit, a data driver and a gate driver. Subpixels are provided on the panel along virtual horizontal lines corresponding to the gate lines. The sensing unit collects sensing data by performing sensing for external compensation on a randomly selected horizontal line among the horizontal lines. The control unit determines a characteristic change of each subpixel using the sensing data, calculates an external compensation value, and uses sensing area compensation values corresponding to areas set along the horizontal line where the sensing is performed to input Image data is converted into sensing area compensation image data. The data driver outputs a sensing area compensation data voltage corresponding to the sensing area compensation image data to a data line formed in the panel. The gate driver sequentially outputs gate pulses to gate lines provided in the panel. The sensing region compensation value is different for each region.

According to the present invention, when external compensation is performed in real time, a phenomenon in which a luminance difference is generated in each area of a panel according to the position of a horizontal line at which sensing is performed can be reduced.

According to the present invention, as block dim or flicker is reduced, image quality can be improved.

1 is an exemplary diagram illustrating a driving method of an organic light emitting display panel proposed in the development stage of the present invention.
2 is an exemplary diagram schematically illustrating the configuration of an organic light emitting display device according to the present invention;
3 is an exemplary view showing the configuration of a control unit applied to an organic light emitting display device according to the present invention;
4 is an exemplary view showing the configuration of a data driver applied to an organic light emitting display device according to the present invention;
5 is an exemplary view showing the structure of pixels formed in a panel applied to an organic light emitting display device according to the present invention;
6 is an exemplary view showing the structure of pixels formed in a panel applied to an organic light emitting display device according to the present invention;
7 is an exemplary view showing the configuration of a gate driver applied to an organic light emitting display device according to the present invention;
8 is a flowchart of an embodiment of a method of driving an organic light emitting display device according to the present invention.
9 is an exemplary diagram illustrating a method of driving an organic light emitting display device according to the present invention.

Advantages and features of the present invention, and methods for achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only the present embodiments make the disclosure of the present invention complete, and those skilled in the art in the art to which the present invention belongs It is provided to fully inform the person of the scope of the invention, and the invention is only defined by the scope of the claims.

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

Since the shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining the embodiment of the present invention are exemplary, the present invention is not limited to the matters shown. Like reference numbers designate like elements throughout the specification. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

In interpreting the components, even if there is no separate explicit description, it is interpreted as including the error range.

In the case of a description of a positional relationship, for example, 'on top of', 'on top of', 'at the bottom of', 'next to', etc. Or, unless 'directly' is used, one or more other parts may be located between the two parts.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal precedence relationship is described in terms of 'after', 'following', 'next to', 'before', etc. It can also include non-continuous cases unless is used.

The term 'at least one' should be understood to include all conceivable combinations from one or more related items. For example, 'at least one of the first item, the second item, and the third item' means not only the first item, the second item, or the third item, but also two of the first item, the second item, and the third item. It means a combination of all items that can be presented from one or more.

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

Each feature of the various embodiments of the present invention can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each embodiment can be implemented independently of each other or can be implemented together in an association relationship. may be

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention can be applied to various types of display devices using external compensation. Hereinafter, for convenience of description, an organic light emitting display device will be described as an example of the present invention.

2 is an exemplary diagram schematically illustrating the configuration of an organic light emitting display device according to the present invention, FIG. 3 is an exemplary diagram showing the configuration of a control unit applied to the organic light emitting display device according to the present invention, and FIG. FIG. 5 is an exemplary view showing the structure of pixels formed in a panel applied to the organic light emitting display device according to the present invention, and FIG. It is an exemplary view showing the structure of a pixel formed on a panel applied to an organic light emitting display device according to the present invention, and FIG. 7 is an exemplary view showing the structure of a gate driver applied to an organic light emitting display device according to the present invention.

An object of the present invention is to reduce a phenomenon in which a luminance difference is generated in each area of a panel according to a position of a horizontal line where sensing is performed when external compensation is performed in real time.

In particular, the present invention relates to an organic light emitting display device using a random progressive sensing method. In an organic light emitting display device using a random progressive sensing method, threshold voltages or mobility of subpixels are sensed on horizontal lines randomly selected according to a predetermined order among virtual horizontal lines corresponding to gate lines. . The horizontal line means a virtual line parallel to at least one gate line.

In addition, in an organic light emitting display device using a random progressive sensing method, during one frame period in which gate pulses are output to all gate lines included in a panel, a gate pulse output to one gate line is delayed so that an image signal is generated. In the blanking time when output is not performed, the threshold voltage or mobility is sensed.

Accordingly, the blanking time during which video is not output is included in one frame period. During the blanking time, the organic light emitting display is driven in a sensing mode.

In an organic light emitting display device using a random progressive sensing method, three regions may be generated. The first area indicates an area disposed above the horizontal line where sensing is performed in the current frame period and disposed above the horizontal line where sensing is performed in the next frame period. The second area represents an area disposed below the horizontal line where sensing is performed in the current frame period and disposed above the horizontal line where sensing is performed in the next frame period. The third area represents an area disposed above the horizontal line where sensing is performed in the current frame period and disposed below the horizontal line where sensing is performed in the next frame period. In addition, there may be a fourth area disposed below the horizontal line where sensing is performed in the current frame period and disposed below the horizontal line where sensing is performed in the next frame period. However, the characteristics of the fourth region are the same as those of the first region (a). Therefore, the present invention will be described below using the above three areas as examples.

As described above, the emission maintenance period is different in the three regions, and thus, a luminance difference may occur between the regions.

The present invention is to prevent a phenomenon in which a luminance difference is generated for each region in an organic light emitting display device using a random progressive sensing method, in which luminance varies according to positions of three regions set along a horizontal line where sensing is performed. .

To this end, in the present invention, external compensation is performed using a sensing value received from a randomly selected horizontal line, and a blanking time starts at a point immediately before addressing for sensing. In the present invention, input image data is converted into sensing region compensation image data using sensing region compensation values corresponding to three regions set along the horizontal line where the sensing is performed. According to the present invention, a luminance difference between regions does not occur.

As shown in FIGS. 2 to 7 , the organic light emitting display device according to the present invention includes subpixels 110 composed of organic light emitting diodes along virtual horizontal lines corresponding to the gate lines GL1 to GLg. A panel 100 equipped with , a sensing unit 320 that collects sensing data by performing sensing for external compensation on a randomly selected horizontal line among the horizontal lines, and each subpixel using the sensing data. A control unit for determining a characteristic change of , calculating an external compensation value, and converting input image data into sensing region compensation image data using sensing region compensation values corresponding to regions set along the horizontal line where the sensing is performed ( 400), a data driver 300 outputting a sensing region compensation data voltage corresponding to the sensing region compensation image data to a data line DL formed in the panel 100 and provided in the panel 100 The gate driver 200 sequentially outputs gate pulses to the gate lines GL1 to GLg. In this case, the sensing area compensation value is different for each area. Here, the sensing unit 320 may be included in the data driver 300 or configured independently of the data driver 300 . Hereinafter, an organic light emitting display device in which the sensing unit 320 is included in the data driver 300 will be described as an example of the present invention. The sensing unit 320, the control unit 400, the data driver 300, and the gate driver 200 are collectively referred to as a panel driver.

First, as shown in FIG. 6 , the panel 100 defines subpixels 110 and a pixel area in which the subpixels 110 are formed and supplies a driving signal to a pixel driving circuit PDC. Signal lines DL, PLA, PLB, SL, and SCL are formed. Each of the subpixels 110 includes an organic light emitting diode (OLED) and the pixel driving circuit (PDC). The pixel driving circuit PDC includes a driving transistor Tdr controlling current flowing through the organic light emitting diode OLED.

First, the signal lines include a scan control line (SCL), a data line (DL), a sensing line (SL), a first driving power supply line (PLA) and a second driving power supply line (PLB).

Next, the scan control lines SCL are formed parallel to each other at regular intervals along the second direction of the panel 100, that is, in the horizontal direction. 6, one gate electrode of the first switching transistor Tsw1 for controlling light emission of the organic light emitting diode (OLED) and one gate electrode of the second switching transistor Tsw2 for sensing the characteristic change of the driving transistor Tdr. Although the sub-pixel 110 commonly connected to the scan control line SCL is shown, the gate electrode of the first switching transistor Tsw1 and the gate electrode of the second switching transistor Tsw2 are different from each other. It can be connected to the scan control line.

For example, a gate electrode of the first switching transistor Tsw1 may be connected to a first scan control line, and a gate electrode of the second switching transistor Tsw2 may be connected to a second scan control line. In this case, when the first switching transistor Tsw1 is turned on, the second switching transistor Tsw2 may be turned off, and when the first switching transistor Tsw1 is turned off, the first switching transistor (Tsw2) can be turned on.

Next, the data lines DL may be formed parallel to each other at regular intervals along the first direction of the panel 100, that is, in the vertical direction, to cross the scan control line SCL.

Next, the sensing lines SL may be formed parallel to the data lines DL at regular intervals.

At least three of the subpixels 110 form one unit pixel 120 . In the following description, as shown in FIG. 5 , four subpixels 110 (red subpixel R, white subpixel W, green subpixel G and blue subpixel B) The present invention will be described taking a case in which this one unit pixel 120 is formed as an example. In this case, one sensing line SL may be commonly connected to the unit pixel 120 . Therefore, when d data lines DL1 to DLd are formed on the horizontal line of the panel 100, the number k of the sensing lines SL becomes d/4.

More specifically, the data lines DL1 to DLd are formed in the first direction (vertical direction) of the panel 100, and the sensing lines SL are formed parallel to the data lines. 5, each of the sensing lines SL is connected to at least three subpixels 110 constituting each of the unit pixels 120 formed on one horizontal line, have. However, the sensing line may be provided for each subpixel.

Next, the first driving power line PLA may be formed parallel to the data line DL at regular intervals. Here, the first driving power line PLA may be formed at regular intervals parallel to the sensing line SL. The first driving power line PLA is connected to a driving power supply unit to supply first driving power EVDD supplied from the driving power supply unit to each subpixel 110 .

Next, the second driving power line PLB is formed as a tube on the entire surface of the panel 100 or parallel to each of the data lines DL1 to DLd or the scan control lines SCL. It may be formed at regular intervals. The second driving power line PLB supplies the second driving power EVSS supplied from the driving power supply to each subpixel 110 . Optionally, the second driving power line may be electrically grounded to a metal case (or cover) constituting the organic light emitting display device. In this case, the second driving power line is grounded to each subpixel 110. Provides power (ground).

Finally, each of the plurality of subpixels 110 is formed in each pixel area defined by each of the scan control lines SCL and each of the data lines DL1 to DLd, which cross each other. Here, each of the plurality of subpixels 110 may be any one of a red subpixel, a green subpixel, a blue subpixel, and a white subpixel.

As shown in FIG. 5 , one unit pixel 120 may include adjacent red subpixels, white subpixels, green subpixels, and blue subpixels, or may include red subpixels, green subpixels, and blue subpixels. can In FIG. 5 , two unit pixels 120 composed of a red subpixel R, a white subpixel W, a green subpixel G, and a blue subpixel B are shown.

As shown in FIG. 6 , each of the plurality of subpixels 110 may include a pixel driving circuit (PDC) and an organic light emitting diode (OLED).

The pixel driving circuit PDC includes a first switching transistor Tsw1, a second switching transistor Tsw2, a driving transistor Tdr, and a capacitor Cst. Here, the transistors Tsw1, Tsw2, and Tdr are thin film transistors (TFTs), and may be a-Si TFTs, poly-Si TFTs, oxide TFTs, organic TFTs, and the like.

The first switching transistor Tsw1 is switched by the gate pulse SP and outputs the data voltage Vdata supplied to the data line DL. To this end, the first switching transistor Tsw1 includes a gate electrode connected to an adjacent scan control line SCL, a first electrode connected to an adjacent data line DL, and a first node that is the gate electrode of the driving transistor Tdr ( and a second electrode connected to n1).

The second switching transistor Tsw2 is switched by a gate pulse and supplies the reference voltage Vref supplied to the sensing line SL to the second node n2 which is the source electrode of the driving transistor Tdr. To this end, the second switching transistor Tsw2 includes a gate electrode connected to a scan control line SCL, a first electrode connected to an adjacent sensing line SL, and a second electrode connected to a second node n2.

The capacitor Cst includes electrodes connected between the gate electrode of the driving transistor Tdr and the first electrode, ie, first and second nodes n1 and n2. For example, a first electrode of the capacitor Cst is connected to the first node n1, and a second electrode of the capacitor Cst is connected to the second node n2. The capacitor Cst is charged with the difference voltage between the voltages supplied to the first and second nodes n1 and n2 according to the switching of the first and second switching transistors Tsw1 and Tsw2, respectively. The driving transistor Tdr is switched according to the voltage.

The driving transistor Tdr is turned on by the voltage of the capacitor Cst to control the amount of current flowing from the first driving power line PLA to the organic light emitting diode OLED. To this end, the driving transistor Tdr includes a gate electrode connected to the first node n1, a first electrode connected to the second node n2, and a second electrode connected to a first driving power line PLA. do.

The organic light emitting diode OLED emits light by the data current Ioled supplied from the driving transistor Tdr and emits light having a luminance corresponding to the data current Ioled. To this end, the organic light emitting diode OLED is formed on the second node n2, that is, a first electrode (eg, an anode electrode) connected to the first electrode of the driving transistor Tdr, and the first electrode. It includes an organic layer and a second electrode (eg, a cathode electrode) connected to the organic layer. The second electrode of the organic light emitting diode may be the second driving power line PLB formed on the organic layer or may be additionally formed on the organic layer to be connected to the second driving power line PLB.

In the above description, the structure of the subpixel 110 for performing external compensation is described with reference to FIG. 6, but the subpixel 110 may be formed in various structures other than the structure shown in FIG. .

For example, external compensation refers to the amount of change in the threshold voltage or mobility of the driving transistor Tdr formed in the subpixel 110, and the amount of data voltage supplied to the unit pixel according to the amount of change. It means changing the size. Accordingly, the structure of the subpixel 110 may be changed in various forms so that the amount of change in the threshold voltage or mobility of the driving transistor Tdr can be calculated.

In addition, for external compensation, a method of calculating the amount of change in the threshold voltage or mobility of the driving transistor Tdr using the subpixel 110 may be variously changed according to the structure of the subpixel 110. can

More specifically, the present invention is to prevent a phenomenon in which a luminance difference is generated between areas set according to the position of a horizontal line where sensing for external compensation is performed in an organic light emitting display device that performs external compensation. . Accordingly, a subpixel structure for external compensation and a method for performing the external compensation may be selected from various subpixel structures and various external compensation methods currently proposed for external compensation. For example, the structure and method of the subpixel for the external compensation and the method for performing the external compensation may be applied to structures and methods disclosed in a number of published patents including Patent Publication No. 10-2013-0066449. In addition, the invention disclosed in Application No. 10-2013-0150057 and Application No. 10-2013-0149213 filed by the present applicant may be applied.

That is, a specific structure of a subpixel for performing external compensation and a specific method of external compensation are outside the scope of the present invention. Accordingly, an example of a subpixel for external compensation has been briefly described with reference to FIG. 6, and an external compensation method is also briefly described below.

Second, the panel driver operates the panel 100 in a sensing mode or a display mode.

The sensing mode means a driving mode of a blank time in which an image is not displayed. That is, the sensing mode means a driving mode during a sensing period. In each of the frame periods, the start time of the blanking time is randomly changed in each frame period. In the sensing mode, an external compensation value for correcting a change in characteristics of the driving transistor Tdr is calculated.

The display mode means a driving mode during a period in which the sensing is not performed. In the display mode, an image is output to the panel 100 . In the display mode, input image data is converted into externally compensated image data using an external compensation value, and an externally compensated data voltage corresponding to the externally compensated image data is supplied to the panel through a data line.

In the sensing mode, the panel driver changes characteristics (eg, threshold voltage or mobility) of the driving transistors Tdr included in each subpixel 110 through each of the first to kth sensing lines. ) is sensed to generate sensing data (Sdata).

The panel driver calculates the external compensation value based on the sensing data Sdata, and corrects the input image data ID input from an external system using the external compensation value to obtain externally compensated image data. generate The panel driver converts the externally compensated image data into an externally compensated data voltage and supplies it to a corresponding subpixel 110 .

For example, the panel driver senses a change in the characteristics of each of the driving transistors Tdr included in each subpixel 110 through each of the sensing lines to individually compensate for the change in the characteristics of the driving transistors Tdr included in each subpixel 110 . and compensates for the input image data (ID) using the sensed change in characteristics of each of the driving transistors (Tdr), and converts the compensated externally compensated image data into externally compensated data voltages so that each subpixel 110 supplied with

As shown in FIGS. 2 to 4 , the panel driving unit includes a sensing unit 320 that collects sensing data Sdata by performing sensing for external compensation for each horizontal line of the panel 100, the sensing data A calculation unit 410 that calculates an external compensation value by determining a characteristic change of each subpixel using (Sdata), using sensing area compensation values corresponding to three areas set along the horizontal line where the sensing is performed. The data arranging unit 430 converts the input image data ID into sensing region compensation image data, and the sensing region compensation data voltage corresponding to the sensing region compensation image data is formed on the panel 100 A data driver 300 outputs to a data line and outputs a sensing data voltage to the data line when the sensing is performed, and a gate driver 200 supplies gate signals GS to the scan control lines SCL includes

Here, the data aligning unit 430 may be formed in the control unit 400 that controls the data driver 300 and the gate driver 200 . The calculation unit 410 may be included in the control unit 400 or may be formed independently of the control unit 400 . The controller 400 includes a control signal generator 420 that generates various control signals DCS and GCS, and the control signals generated from the control signal generator 420 are transmitted to the gate driver 200 and the data driver. 300 or the output unit 440 for transmitting sensing area compensation image data (Data) generated from the data aligning unit 430 to the data driver 300 may be further included.

The sensing unit 320 may be formed in the data driver 300 or may be formed independently of the data driver 300 . Hereinafter, as shown in FIG. 4, the sensing unit 320 is included in the data driver 300, and the calculating unit 410, as shown in FIG. 3, the controller 400 ) as an example, the organic light emitting display device according to the present invention will be described.

In this case, as shown in FIG. 4 , the data driver 300 may include a data voltage output unit 310 supplying various data voltages Vdata to the panel and the sensing unit 320. . However, the panel driving unit applied to the organic light emitting display device according to the present invention may be formed in various structures other than the structure described below.

First, the controller 400 generates a gate control signal (GCS) for controlling driving of the gate driver 200 and driving of the data driver 300 based on a timing synchronization signal (TSS) input from an external system. Each generates a data control signal (DCS) for controlling.

In addition, the control unit 400 transmits, to the data driver 300 , sensing image data to be supplied to pixels formed on a horizontal line where external compensation is performed.

Sensing for the external compensation is performed during the blanking time. The start time of the blanking time is different for each frame period. The starting point of the blanking time is randomly preset and stored in the storage unit 450 .

In the sensing mode in which the sensing is performed, the control unit 400 calculates the external compensation value based on the sensing data Sdata provided from the data driver 300, and stores the external compensation value in the storage unit 450. save to The storage unit 450 may be included in the control unit 400 or may be independently formed outside the control unit 400 .

The control unit 400 converts the input image data into sensing area compensation image data (Data) using external compensation values and sensing area compensation values corresponding to three areas set according to the horizontal line where the sensing is performed. let it

As described above, the areas are arranged on top of the horizontal line where sensing is performed in the current frame period, and the first area is arranged on top of the sensing line where sensing is performed in the next frame period. A second area disposed at the bottom of the horizontal line formed and disposed at the top of the horizontal line where sensing is performed in the next frame period, disposed at the top of the horizontal line where sensing is performed in the current frame period, and where sensing is performed in the next frame period It includes a region disposed at the lower end of the horizontal line and a fourth region disposed at the lower end of the horizontal line where sensing is performed in the current frame period and disposed at the lower end of the horizontal line where sensing is performed in the next frame period. Here, the characteristics of the fourth region are the same as those of the first region. Therefore, in the following, the present invention will be described taking the first region, the second region, and the third region as an example.

When the input image data is received, the controller 400 determines a region corresponding to the input image data among the three regions (first to third regions), and compensates for the sensing region corresponding to the region. A value is applied to the input image data and converted into the sensing area compensation image data (Data).

In addition, when the input image data is received, the controller 400 determines a region corresponding to the input image data among the three regions (first to third regions). The control unit 400 applies a sensing area compensation value corresponding to the area and an external compensation value corresponding to a subpixel to which the input image data is to be output to the input image data to obtain the sensing area compensation image data (Data). convert The controller outputs the sensing area compensation image data Data to the data driver 300 (or the data voltage output unit 310).

The data driver 300 (or the data voltage output unit 310) outputs a data voltage corresponding to the sensing area compensation image data to a data line formed in the panel every horizontal period.

Therefore, when there is no external compensation value corresponding to the subpixel to which the input image data ID is to be output, the sensing region compensation image data Data is obtained by using the input image data ID and the sensing region compensation value. is created

When an external compensation value corresponding to a subpixel to which the input image data ID is to be output is calculated, the sensing area compensation image data Data includes the input image data ID, the external compensation value, and the sensing area compensation value. created using values.

In order to perform the above function, the control unit 400, as shown in FIG. 3, uses the timing synchronization signal (TSS) transmitted from the external system to input image data (transmitted from the external system) ID) rearranged using at least one of an external compensation value and a sensing region compensation value, and a data aligning unit 430 for supplying the rearranged sensing region compensation image data (Data) to the data driver 300, the timing The control signal generation unit 420 for generating the gate control signal (GCS), the data control signal (DCS), and the power control signal (PCS) using a synchronization signal, and the data driver 300 transmits the A calculation unit 410 for calculating an external compensation value for compensating for a change in the characteristics of the driving transistor formed in each of the pixels using the sensing data Sdata; Various sensing area compensation image data (Data) and various control signals (DCS, GCS) generated in the storage unit 450 for storing the sensing area compensation value and the data sorting unit 430 are stored in the data driver 300. ) or an output unit 440 for outputting to the gate driver 200.

The calculation unit 410 determines the characteristic change of each subpixel using the sensing data, and calculates the external compensation value. For example, in the sensing mode performed at the blanking time, the calculation unit 410 senses a characteristic change of the organic light emitting diodes using the sensing data Sdata. The calculation unit 410 may calculate the external compensation value according to the characteristic change and store the external compensation value in the storage unit 450 .

The data aligning unit 430 uses a timing synchronization signal (TSS) transmitted from the external system to set at least one of an external compensation value and a sensing region compensation value for the input image data (ID) transmitted from the external system. After realigning using the sensor, the rearranged sensing area compensation image data Data is supplied to the data driver 300 .

The control signal generation unit 420 performs a function of generating various control signals required in the present invention.

As described above, the storage unit 450 stores the sensing area compensation value and the external compensation value transmitted from the calculation unit 410 and transmits them to the data sorting unit 430. do. Also, the storage unit 450 stores the order of horizontal lines to be sensed. The order may be randomly preset. For example, when the number of gate lines is 2160, sensing is performed on subpixels connected to the 10th gate line in the first frame period, and sensing is performed on subpixels connected to the 25th gate line in the second frame period. Sensing may be performed for subpixels connected to the 1000th gate line in the third frame period. That is, in the present invention, random means that the order of horizontal lines that are sensed is not sequentially performed from the top (or bottom) of the panel to the bottom, but in an irregular order. However, a random order is preset and stored in the storage unit 450 . Accordingly, the control unit 400 can know the horizontal line on which sensing is performed.

As described above, the controller 400 randomly selects a horizontal line to be sensed for external compensation in each frame period according to a preset order.

The sensing area compensation values applied to subpixels included in any one of the three areas may be the same.

However, the sensing area compensation values applied to subpixels included in any one of the three areas may be different. For example, the sensing area compensation values applied to subpixels included in any one area may differ according to at least one of colors and grays of input image data corresponding to the subpixels. . In this case, the sensing area compensation values applied to subpixels included in any one of the areas are reference sensing area compensation values commonly applied to all subpixels included in any one area. value, and an auxiliary sensing region compensation value that is changed according to at least one of color and gray of the input image data corresponding to the subpixel provided in any one of the regions.

Next, the gate driver 200 sequentially generates gate pulses in response to the gate control signal GCS supplied from the controller 400 and sequentially supplies them to the scan control lines SCL.

Here, the gate control signal GCS may include a start signal and a plurality of clock signals.

While the gate pulse is not output to the gate line, a turn-off signal for turning off the first switching transistor Tsw1 connected to the gate line is output to the gate line. The gate pulse and the turn-off signal are collectively referred to as a gate signal GS.

The gate driver 200 may be directly formed on the panel 100 together with the thin film transistor formation process of each subpixel 110, or may be formed in the form of an integrated circuit (IC) and mounted on the panel. have.

A type in which the gate driver 200 is directly formed on the panel 100 is referred to as a Gate In Panel (GIP) type. As shown in FIG. 7 , the GIP type gate driver 200 may include a plurality of stages (Satage1 to Stage g). In the stages, the gate pulses GP1 to GPg are sequentially output.

The gate pulse output from the previous stage may serve to drive the subsequent stage. In this case, at least one other stage may be provided between the front stage and the rear stage.

The gate driver 200 may perform a function of delaying a gate pulse output to a gate line corresponding to the horizontal line on which the sensing is performed until the sensing is completed.

To this end, the gate driver 200 may include a delay unit 210 that delays a gate pulse output from a previous stage and supplied to a subsequent stage. The delay unit 210 may be driven according to a gate pulse control signal (GPCS) transmitted from the control unit 400 .

For example, a gate pulse output from a previous stage and supplied to a subsequent stage where sensing is performed is not supplied to the subsequent stage by the delay unit 210 . During a sensing period in which the gate pulse is not supplied to the subsequent stage, the controller 400 may sense subpixels provided on a horizontal line corresponding to a gate line connected to the subsequent stage to calculate an external compensation value. .

When the sensing period ends, the delay unit 210 supplies the gate pulse to the subsequent stage. Accordingly, a gate pulse is supplied to subpixels provided on a horizontal line corresponding to the gate line connected to the next stage, and the subpixels output an image.

The delay unit 210 may be configured in various forms capable of performing the functions described above.

Next, the data driver 300 is connected to the data lines DL1 to DLd and the sensing lines, and operates in a sensing mode or a display mode according to a control signal transmitted from the controller 400 . As shown in FIG. 4 , when the data driver 300 includes the data voltage output unit 310 and the sensing unit 320, the data voltage output unit 310 is connected to the data line DL. , and the sensing unit 320 is connected to the sensing lines SL.

The sensing unit 320 supplies a reference voltage to each of the sensing lines in the sensing mode. Then, the sensing unit 320 receives an analog signal corresponding to the reference voltage. The sensing unit 320 converts the analog signal into a digital signal, that is, the sensing data Sdata. The sensing unit 320 transmits the sensing data to the calculating unit 410 . Accordingly, changes in characteristics of the driving transistors Tdr included in the subpixels 110 formed on one horizontal line may be sensed.

To this end, the subpixels may be configured as shown in FIG. 5 . For example, one sensing line SL is provided for each unit pixel 120 composed of R, G, B, and W subpixels 110 among subpixels formed on one horizontal line. is formed Accordingly, when one sensing data voltage is supplied through each sensing line SL, sensing data for one subpixel of each unit pixel 120 is transmitted to the sensing unit 320 . Since one unit pixel 120 is formed of four subpixels, when four sensing data voltages are supplied through the sensing line SL, all subpixels formed on one horizontal line Sensing data may be generated. Sensing data for all subpixels formed on the one horizontal line is transmitted to the calculation unit 410, and the calculation unit 410 uses the sensing data to perform external compensation for the subpixels. value can be calculated.

In the sensing mode, the data voltage output unit 310 converts the output image data transmitted from the control unit 400, ie, the sensing image data, into a sensing data voltage and supplies it to the data line. The data voltage output unit 310 generates sensing area compensation image data DATA supplied from the control unit 400 in units of horizontal lines using a plurality of reference gamma voltages supplied from the reference gamma voltage supply unit in the display mode. is converted into a sensing area compensation data voltage and supplied to the corresponding data lines DL1 to DLd.

The data voltage output unit 310 samples the sensing area compensation image data DATA of each subpixel 110 input in units of one horizontal line according to the data control signal DCS, and the plurality of reference gamma voltages. Among them, a gamma voltage corresponding to a grayscale value of sampling data is selected as the sensing region compensation data voltage and supplied to the corresponding data line DL of each subpixel 110 .

Finally, in the sensing mode, the sensing unit 320 senses the voltage of each of the sensing lines, generates sensing data Sdata corresponding to the sensing voltage, and provides the generated sensing data Sdata to the control unit 400 . To this end, the sensing unit 320 may include an analog-to-digital converter that converts the sensing voltage transmitted from the sensing lines into digital to generate the sensing data Sdata.

The sensing unit 320 performs the sensing during a blanking time when data voltages are not output to data lines during one frame period.

In other words, the sensing unit 320 does not output an image signal because the gate pulse output to any one gate line is delayed during the one frame period during which the gate pulse is output to all of the gate lines. The sensing is performed at the blanking time, which is not specified.

8 is a flowchart of an embodiment of a method of driving an organic light emitting display device according to the present invention, and FIG. 9 is an exemplary diagram illustrating a method of driving an organic light emitting display device according to the present invention. In FIG. 9 , the vertical axis represents upper and lower portions of the organic light emitting display panel. Accordingly, FIG. 9 shows an organic light emitting display panel having 2160 horizontal lines. In FIG. 9 , the horizontal axis represents time. Assuming that one frame period is 8.3 ms, Fig. 1 shows three frame periods. However, since FIG. 9 is for explaining the three areas (x, y, z) described above, the frame periods shown in FIG. 9 do not represent a temporal order. For example, in terms of the first area (x) and the second area (y), a period between 0 and 8.3 ms is the current frame period, and a period between 8.3 and 16.6 ms is the next frame period. Also, from the perspective of the third region (z), the period between 8.3 and 16.6 ms is the current frame period, and the period between 16.6 and 24.9 ms is the next frame period. In the following description, the same or similar contents as those described above are omitted or simply described.

First, the sensing area compensation values are stored in the storage unit 450 for each of the three areas (S702).

The three regions described above may be divided as shown in FIG. 9 .

The first area (x) represents an area disposed above the horizontal line where sensing is performed in the current frame period and disposed above the horizontal line where sensing is performed in the next frame period.

The second area y represents an area disposed below the horizontal line where sensing is performed in the current frame period and disposed above the horizontal line where sensing is performed in the next frame period.

The third area z represents an area disposed above the horizontal line where sensing is performed in the current frame period and disposed below the horizontal line where sensing is performed in the next frame period.

In addition, there may be a fourth area disposed below the horizontal line where sensing is performed in the current frame period and disposed below the horizontal line where sensing is performed in the next frame period. However, the characteristics of the fourth region are the same as those of the first region (x). Accordingly, the present invention will be described below using the three regions (x, y, z) as examples.

The sensing region compensation value is a value for compensating for luminance deviation of the three regions. The sensing region compensation value is changed according to the input image data, and may be used when luminance of the input image data is calculated. More specifically, the voltage added to or subtracted from the input image data as a result of the luminance calculation based on the sensing region compensation value may vary depending on the input image data.

The sensing area compensation value is calculated using various information calculated when the sensing for the external compensation is actually executed in the manufacturing process of the panel 110 or calculated through various simulations, and then the It may be stored in the storage unit 450 .

First, the sensing area compensation values are different for each of the three areas. For example, as shown in FIG. 9 , based on the first area (x), the light emission period of the second area (y) is smaller than the light emission period of the first area (x); The light emission period of the third region (z) is longer than the light emission period of the first region (x).

Therefore, when the sensing area compensation value applied to the subpixels in the first area (x) has a value that does not change the luminance of the subpixels in the first area (y), the second area The sensing area compensation value applied to the subpixels included in (y) may have a value that increases the luminance of the subpixels provided in the second area (y). In this case, the sensing area compensation value applied to the subpixels included in the third area z may have a value that reduces the luminance of the subpixels included in the third area z.

Second, the sensing area compensation values applied to subpixels included in any one of the areas may be the same.

Third, the sensing area compensation values applied to subpixels included in any one of the areas are reference sensing area compensation values commonly applied to all subpixels included in any one area. , and an auxiliary sensing region compensation value that is changed according to at least one of color and gray of the input image data corresponding to the subpixel provided in any one of the regions.

For example, even if the sensing area compensation values are applied to subpixels included in one area, the sensing area compensation values may be different depending on the gray of the input image data corresponding to the subpixel, and the horizontal Sensing area compensation values may be different according to the position of the line in the panel, and sensing area compensation values may be different according to the color corresponding to the input image data corresponding to the subpixel, and the input image data corresponding to the subpixel Sensing area compensation values may be different according to at least one of gray, a position of a horizontal line including a subpixel, and a color corresponding to a subpixel.

To elaborate, even if the sensing area compensation values correspond to subpixels included in one area, the sensing area compensation values may be different according to the color of the input image data. For example, the compensation value for the R input image data corresponding to the R subpixel is 0.01V, the compensation value for the W input image data corresponding to the W subpixel is 0.013V, and the G input image data corresponding to the G subpixel A compensation value for B may be 0.011V, and a compensation value for B input image data corresponding to B subpixel may be 0.009V.

Also, even if the sensing area compensation values correspond to subpixels included in one area, the sensing area compensation values may be different according to the gray of the input image data.

In addition, even if the sensing area compensation values correspond to subpixels included in one area, the sensing area compensation values may be different according to the position of a horizontal line where a subpixel to which input image data is to be output is formed.

In addition, even if the sensing area compensation values correspond to subpixels included in one area, the sensing area compensation values may be different according to at least two of the gray of the input image data, the position of the horizontal line, and the color. . As described above, since the sensing area compensation value can be variously changed according to the gray of the input image data, the position of the horizontal line, and the color, the sensing area compensation value is calculated by considering all of the above information. can

Next, in the blanking time, that is, in the sensing mode, a data voltage is sequentially supplied to subpixels constituting one unit pixel 120, and a change in characteristics of driving transistors formed in each of the pixels is sensed. . That is, sensing for external compensation is performed on a randomly selected horizontal line (S704).

In this case, as shown in FIG. 5 , one sensing line may be formed in the unit pixel 120 . That is, while the reference voltage is applied to one sensing line, the data voltage is supplied to only one data line among the pixels forming the unit pixel, and thus the driving transistor formed in the subpixel to which the data voltage is supplied. A change in the characteristics of can be detected.

The calculator 410 may calculate the external compensation value using the sensing data. As a specific method of calculating the external compensation value, as described above, methods described in published patent documents and various patent documents applied by the present applicant may be applied.

As shown in FIG. 9 , the sensing mode is executed at a blank time included in one frame period. One frame period may be 8.3 ms, for example, as shown in FIG. 9 .

During the blanking time, data voltages are not output to the data lines. However, since the data voltage already charged in each subpixel formed on each horizontal line HL is continuously maintained, an image can be output through the panel even during the blanking time.

However, since the sensing data voltage for the sensing is supplied to the subpixels formed on the horizontal line where the sensing is performed, in the subpixels formed on the horizontal line where the sensing is performed, the sensing data voltage for the sensing is supplied at the blanking time. An image may not be output during the blanking time.

Next, the control unit 400, in particular, the data aligning unit 430 rearranges the input image data (ID) transmitted from the external system using the sensing region compensation values to generate the sensing region compensation image data, , The sensing region compensation image data is transmitted to the data voltage output unit 310 .

For example, when the sensing area compensation value applied to the subpixels in the first area (x) has a value that does not change the luminance of the subpixels in the first area (y), the two The sensing area compensation value applied to the subpixels included in the second area y may have a value that increases the luminance of the subpixels included in the second area y. In this case, the sensing area compensation value applied to the subpixels included in the third area z may have a value that reduces the luminance of the subpixels included in the third area z.

Therefore, the luminance of the second region (y) having a shorter emission time than the first region (x) may be increased, and the luminance of the third region (z) having a longer emission time than the first region (x) may decrease. It can be. Accordingly, a luminance difference in the three areas (x, y, z) does not occur.

An example of a method of generating the sensing area compensation image data by using the sensing area compensation value by the controller 400 is as follows.

First, the emission duty of the first region (x) may be a total of 8.3 ms, including an active period and a blanking period (Duty: Active (8 ms) + Blank (0.3 ms) = 8.3 ms). ms). In this case, the relationship between the input luminance data (LDATA) of the input image data input to the controller 400 and the output luminance data (LDATA') of the sensing region compensation image data output from the controller 400 is the corresponding region LDATA' = LDATA x Scale_x multiplied by the weight (Scale_x), and since the emission duty consists of an active period and a blanking period, Scale_x may be 1.

에 의해 생성된 값이다.where [1] is

is the value generated by

Second, the emission duty of the second region y corresponds to the active period, and thus may be 8 ms in total. In this case, LDATA' = LDATA x Scale_y, and Scale_y may be (8.3/8) (Duty: Active = 8ms).

에 의해 생성된 값이다.where [8.3/8] is

is the value generated by

Third, the emission duty of the third region (z) may include an active period and twice as many blanking periods (Duty: Active + 2 x Blank). In this case, LDATA' = LDATA x Scale_z, and Scale_z may be (8.3/8.6).

에 의해 생성된 값이다.where [8.3/8.6] is

is the value generated by

Finally, the data voltage output unit 310 outputs the sensing area compensation data voltage to which the sensing area compensation value is applied to the subpixels of the horizontal line on which sensing is not performed (S706).

That is, the data voltage output unit 310 converts the sensing area compensation image data transmitted from the control unit 400 into a sensing area compensation data voltage, and then outputs the sensing area compensation data voltage to a data line.

The present invention is summarized as follows.

The present invention is to improve BlockDim, which occurs due to differences in the duration of light emission of frames between vertical blocks due to differences in sensing lines of previous/current/later frames during random progressive sensing.

To this end, the present invention predicts the frame emission duration time between blocks of the current frame using the information of the previous / present / future sensing lines, and in order to correct the difference in luminance according to the emission duration time, different weights for luminance between blocks, That is, it is characterized in that a sensing area compensation value is given.

Here, it can be expressed as final luminance between blocks = light emission duration X weight.

In this case, each scale (weight) can be classified into three types by a combination of Active Time and Blank TIme, as described above.

The final output compares the Sensing Line of the previous / current / next frame, applies the scale value to the block status, and the formula for obtaining the final output is as follows.

Those skilled in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing its technical spirit or essential features. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and 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
110: sub-pixel 120: unit pixel
410: calculation unit 420: control signal generation unit
430: data sorting unit 440: output unit
450: storage unit 310: data voltage output unit
320: sensing unit

Claims (10)

a panel having subpixels along virtual horizontal lines corresponding to the gate lines;
a sensing unit configured to collect sensing data by performing sensing for external compensation on a randomly selected horizontal line among the horizontal lines;
Using the sensing data, a characteristic change of each subpixel is determined to calculate an external compensation value, and input image data is obtained using sensing area compensation values corresponding to areas set along the horizontal line where the sensing is performed. a control unit for converting sensing area compensation image data;
a data driver outputting a sensing area compensation data voltage corresponding to the sensing area compensation image data to a data line formed in the panel; and
a gate driver sequentially outputting gate pulses to gate lines provided in the panel;
The sensing region compensation value is different for each region. According to claim 1,
These areas are
Arranged at the top of the horizontal line where sensing is performed in the current frame period and arranged at the top of the sensing line where sensing is performed in the next frame period, or arranged at the bottom of the horizontal line where sensing is performed in the current frame period and in the next frame A first area disposed at the lower end of the horizontal line where sensing is performed in the period;
A second area disposed below the horizontal line where sensing is performed in the current frame period and disposed above the horizontal line where sensing is performed in the next frame period; and
An organic light emitting display device including a third region disposed above a horizontal line where sensing is performed in a current frame period and disposed below a horizontal line where sensing is performed in a next frame period. According to claim 1,
The control unit,
An organic light emitting display device that randomly selects a horizontal line to be sensed for external compensation in each frame period according to a preset order. According to claim 1,
The control unit,
When the input image data is received, determining a region corresponding to the input image data among the regions, and converting the input image data into the sensing region compensated image data using a sensing region compensation value corresponding to the region organic light emitting display. According to claim 1,
The control unit,
When the input image data is received, a region corresponding to the input image data is determined among the regions, and a sensing region compensation value corresponding to the region and an external compensation value corresponding to a subpixel to which the input image data is to be output are determined. converting the input image data into the sensing area compensation image data using
wherein the data driver outputs a sensing area compensation data voltage corresponding to the sensing area compensation image data to a data line formed on the panel every horizontal period. According to claim 1,
The sensing area compensation values applied to subpixels included in any one of the areas are identical to the organic light emitting display device. According to claim 1,
The sensing area compensation values applied to subpixels included in any one of the areas,
A reference sensing area compensation value commonly applied to all subpixels provided in any one area, and
An organic light emitting display device comprising an auxiliary sensing region compensation value that is changed according to at least one of color and gray of input image data corresponding to a subpixel provided in any one of the regions. According to claim 1,
The sensing unit performs the sensing during a blanking time when an image signal is not output because a gate pulse output to one gate line is delayed during one frame period during which the gate pulse is output to all of the gate lines. organic light emitting display. According to claim 1,
The gate driver,
An organic light emitting display device that delays a gate pulse output to a gate line corresponding to the horizontal line on which the sensing is performed until the sensing is completed. According to claim 2,
When the sensing area compensation value applied to the subpixels in the first area has a value that does not change the luminance of the subpixels in the first area, it is applied to the subpixels in the second area. The sensing area compensation value has a value that increases the luminance of the subpixels provided in the second area, and the sensing area compensation value applied to the subpixels provided in the third area has a value provided in the third area. An organic light emitting display device having a value for reducing luminance of subpixels.

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