KR20160007883A - Display device - Google Patents

Abstract

The present invention relates to a display device, and more particularly, the present invention has a technical objective to provide a display device which changes the order of colors of sensed subpixels for every sensing period. In order to accomplish this, the display device according to the present invention comprises: a panel in which subpixels constituting unit pixels are formed on every horizontal line, wherein the panel is formed such that a sensing process for an external compensation can be performed on every horizontal line; a sensing unit which, during a sensing period, performs the sensing process for external compensation on every horizontal line of the panel to collect sensing data including feature information of the subpixels, and changes the order of colors of the sensed subpixels for every sensing period; a calculating unit which determines a change of feature in each subpixel by using the sensing data to calculate an external compensation value; a control unit which transmits a control signal to the sensing unit, when a turn-off signal is received from an external system, to drive the sensing unit, rearranges input image data by using the external compensation value, when a turn-on signal is received from the external system, and outputs the rearranged output image data; and a data driver which converts the output image data to an output data voltage and supplies the output data voltage to the data lines which are formed on the panel.

Description

Display device {DISPLAY DEVICE}

The present invention relates to a display device, and more particularly, to a display device that performs 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 notebook computers. The flat panel display device includes a liquid crystal display device (LCD), a plasma display panel device (PDP), and an organic light-emitting diode display device (OLED) Electrophoretic display devices (EPDs) are also widely used.

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

That is, the organic light emitting display device is a self light emitting device that emits an organic light emitting diode by using an electron and a hole recombination to display an image, has a high response speed and low power consumption, and uses a self light emitting device Therefore, it has an excellent viewing angle. Therefore, the organic light emitting display device is attracting attention as a next generation flat panel display.

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

In order to solve the above problem, Korean Patent Laid-Open Publication No. 10-2013-0066449 (hereinafter referred to as "Prior Art Document") discloses a technique of correcting the characteristic change of driving transistors included in each sub- Compensating external compensation method is disclosed.

FIG. 1 is a view for explaining an ideal method for performing sensing for external compensation in a conventional organic light emitting diode display, and FIG. 2 is a diagram for explaining a method of performing sensing for external compensation in a conventional organic light emitting diode Fig.

In order to perform the external compensation as described above, the sub-pixels must be continuously sensed.

In the organic light emitting display, the sensing for external compensation is generally performed in units of one horizontal line. For example, a vertical blank time or an electronic product in which an organic light emitting display is mounted, between a frame and a frame, (Hereinafter simply referred to as "turn-off time") of a TV, a monitor, a smart phone, a personal computer (PC) or a tablet PC ought.

In addition, the sensing is performed for each color.

For example, when red pixels, white pixels, green pixels, and blue pixels are formed on one horizontal line, a conventional OLED display first senses threshold voltages or mobilities of red pixels And then sensing and storing the threshold voltage or mobility of the white pixels and then sensing and storing the threshold voltage or mobility of the green pixels and finally storing the threshold voltage or mobility of the blue pixels Sensing and storing. Thereafter, the above-described process is repeated for the pixels formed in the next horizontal line. That is, in the conventional OLED display, sensing is performed in a fixed order with respect to four colors.

As described above, the threshold voltage (Vth) or the mobility of the driving transistor formed in each subpixel of the OLED display device is shown in Figs. 1 (a) and 2 (a) As time goes by, it changes. Therefore, when the organic light emitting display is used by the user, the magnitude of the data voltage supplied to the sub pixels continuously through the external compensation must be compensated.

Generally, the period for sensing the mobility is shorter than the period for sensing the threshold voltage. Therefore, the period of sensing the mobility can be made at the blank time between the frame and the frame. However, since the period for sensing the threshold voltage takes 10 ms or more per line, as shown in FIG. 1 (b), the threshold voltage sensing is performed such that the organic light emitting display is turned off Timing, that is, the turn-off time.

In an organic light emitting display device to which a unit pixel including red (R), green (G), blue (B) and white (W) subpixels is applied, A sub-pixel, a white sub-pixel, a green sub-pixel, and a blue sub-pixel in that order. In this case, when the sensing for one color is completed in all the horizontal lines, the sensing data for the corresponding color is stored in the memory.

In a panel applied to an ultra high definition (UHD) organic light emitting display, 2160 horizontal lines are formed, and a sensing period for one horizontal line is about 10 ms. Therefore, 21.6s (= 2160 x 10 ms) is required for all the subpixels for one color in the panel to be sensed. Therefore, 86.4s (= 21.6s x 4) is required for all the subpixels in the panel to be sensed.

For example, if the four colors are perfectly sensed at the turn-off timing, the data voltage supplied to each subpixel can be accurately compensated. In this case, as shown in Fig. 1 (b), even if time elapses, the luminance of each subpixel can be kept constant.

However, if the user turns the electronic product on again immediately after turning off the electronic product, the sensing operation is stopped. In addition, if the user disconnects the power supply line of the electronic product from the power supply immediately after turning off the electronic product, the sensing operation is stopped.

Therefore, the sensing period of 86.4s required for the sensing operation can not always be ensured.

For example, when the electronic product is turned on again after elapse of 25 seconds after the electronic product is turned off, sensing for the red subpixels is completed, but white subpixels, green subpixels, and blue subpixels Sensing is not completed. Thus, only the external compensation value for the red subpixels can be applied to the red subpixels.

When the above operation is repeated, as shown in FIG. 2B, the luminance of the red subpixel can be maintained constant over time, but the luminance of the remaining subpixels increases with time It becomes smaller.

That is, if the above operation is repeated, in the conventional organic light emitting display, external compensation for all the subpixels is not uniform.

Also, if the degradation rates of all the color subpixels are all the same, the luminance of all the color subpixels must be reduced equally. However, in general, the luminance is lowered in the order of the green subpixel, the red subpixel, and the blue subpixel, and the white subpixel is the highest. Therefore, even if the degradation rates are the same, the brightness of the white subpixels is the greatest decrease and the brightness of the blue subpixels is the smallest.

Therefore, if the external compensation for the white subpixels is not properly performed, the quality of the image may be degraded.

However, in the conventional display device, all the subpixels are not evenly sensed and compensated, and the sensing operation considering white subpixels can not be performed.

SUMMARY OF THE INVENTION It is a general object of the present invention to provide a display device which changes the order of colors of subpixels to be sensed in each sensing period for external compensation.

According to an aspect of the present invention, there is provided a display device including: a panel having subpixels constituting unit pixels for each horizontal line, and sensing for external compensation per horizontal line; When the sensing period arrives, sensing for external compensation is performed for each horizontal line of the panel, and the sensing data including the characteristic information of the sub pixels is collected, and the order of the colors of the sub pixels to be sensed Sensing unit; A calculating unit for determining a characteristic change of each subpixel using the sensing data and calculating an external compensation value; And when the turn-off signal is received from the external system, the control unit transmits the control signal to the sensing unit to drive the sensing unit. When the turn-on signal is received from the external system, the input image data is rearranged using the external compensation value, Outputting the output image data; And a data driver converting the output image data into an output data voltage and supplying the output data voltage to the data lines formed on the panel.

According to the present invention, the function of compensating the characteristics of subpixels corresponding to all colors can be improved.

Further, according to the present invention, the function of compensating for subpixels corresponding to a color which is vulnerable to deterioration can be improved.

1 is an exemplary diagram for explaining an ideal method of performing sensing for external compensation in a conventional OLED display.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting display.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]
4 is a diagram illustrating a configuration of a control unit applied to an organic light emitting display according to an embodiment of the present invention.
5 is a diagram illustrating a configuration of a data driver applied to an organic light emitting display according to an embodiment of the present invention.
6 is a view illustrating a structure of pixels formed on a panel applied to an OLED display according to an exemplary embodiment of the present invention.
7 is a view illustrating a structure of a pixel formed on a panel applied to the organic light emitting display according to the present invention.
FIG. 8 is a flowchart illustrating a method of driving an organic light emitting display according to an embodiment of the present invention. Referring to FIG.
9 is a graph illustrating luminance characteristics of an organic light emitting display according to an embodiment of the present invention.

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 kinds of display devices using external compensation. Hereinafter, for convenience of explanation, an organic light emitting display device will be described as an example of the present invention.

FIG. 3 is a schematic view illustrating the configuration of an OLED display according to the present invention. FIG. 4 is a view illustrating a configuration of a control unit applied to the OLED display according to the present invention. 6 is a view illustrating a structure of pixels formed on a panel applied to an organic light emitting diode display according to an embodiment of the present invention. FIG. 5 is a view illustrating a structure of a pixel formed on a panel applied to an organic light emitting display according to an embodiment of the present invention.

In general, a blank time, or an electronic product equipped with an organic light emitting display, such as a TV, a monitor, a smart phone, a personal computer (PC), or a tablet PC (Hereinafter simply referred to as " turn-off time "), the sensing for real-time external compensation is performed. Here, the sensing is performed for each subpixel. In this case, the threshold voltage (Vth) or mobility of the subpixel is sensed. Particularly, when the sensing period (hereinafter, simply referred to as a sensing period) occurs at the turn-off time, the electronic product is turned on again at the turn-off time, or the turn- Immediately after the supply of power to the electronic product is interrupted, all of the subpixels may not be sensed.

In order to solve the above problem, the present invention changes the order of colors of subpixels to be sensed every sensing period for external compensation, which comes at the turn-off time, and uses the sensing data sensed during the sensing period, Compensates the data voltage supplied to the subpixels. The sensing period may be included in the blank time, or may be in the turn off time. However, for convenience of explanation, the present invention will be described below as an example in which the sensing period comes to the turn-off time.

Here, the turn-off time means a period after the user turns off the electronic product using a switch or a button. Even when the electronic product is turned off, the electronic product is connected to the power supply through the power supply line, so that the sensing for the external compensation can be performed during the turn-off time. In other words, when the user turns off the electronic product, and the turn-off time comes, it is considered that the electronic product is not driven externally. However, in the turn-off time, the organic light emitting diode display according to the present invention, which is built in the electronic product or the electronic product, can perform the sensing operation for the external compensation using the power supplied from the power supply unit have. However, if the power supply line is disconnected from the power supply unit and power is not supplied to the electronic product, the organic light emitting display according to the present invention can not perform the sensing operation at the turn-off time.

In the following description, the subpixel means a pixel which outputs red, green, blue or white light. However, the subpixels may be separated by a color filter.

The unit pixel is composed of the subpixels, and outputs white light. For example, the unit pixel may be composed of a red subpixel, a green subpixel, and a blue subpixel, or a red subpixel, a green subpixel, a blue subpixel, and a white subpixel. Hereinafter, for convenience of explanation, the present invention will be described by taking the case where the unit pixel is composed of four sub-pixels, for example, a red sub-pixel, a green sub-pixel, a blue sub-pixel and a white sub-pixel.

The sensing subpixel means a subpixel in which the characteristic is sensed. The data sensed in the sensing subpixel, that is, the data including the change amount or information of the characteristic (hereinafter simply referred to as characteristic information) is referred to as sensing data.

The horizontal line is an imaginary line perpendicular to the data line. The horizontal line may correspond to one gate line. In one horizontal line, a plurality of the unit pixels are formed.

3 to 7, subpixels 110 constituting unit pixels 120 are formed for each horizontal line, and the sensing for external compensation is horizontal The panel 100 is configured to be able to perform external compensation for each horizontal line of the panel 100 when the sensing period comes, The sensing unit 320 collects data and changes the order of the colors of the subpixels 110 sensed at each sensing period. The sensing unit 320 determines changes in the characteristics of the subpixels 110 using the sensing data, Off signal is received from an external system (not shown), a control signal is transmitted to the sensing unit 320 to drive the sensing unit 320, and a signal from the external system Turn on new A controller 400 for rearranging the input image data using the external compensation value and outputting the rearranged output image data, and a controller 400 for converting the output image data into an output data voltage, And a data driver 300 for supplying the data to the data lines. Here, the sensing unit 320, the calculating unit 410, the data arranging unit 430, the data driver 300, and the gate driver 200 are collectively referred to as a panel driving unit.

7, the panel 100 includes a pixel driving circuit (not shown) including an organic light emitting diode OLED and a driving transistor Tdr for controlling a current flowing through the organic light emitting diode OLED (PDC), and a signal line for defining a pixel region where the subpixels 110 are formed and supplying a driving signal to the pixel driving circuit PDC.

First, the signal lines are connected to a scan control line SCL, a sensing control line SSCL, a data line DL, a sensing line SL, a first driving power supply line PLA and a second driving power supply line PLB Includes.

Next, the scan control lines SCL are formed so as to be spaced apart from each other along the second direction of the panel 100, that is, the horizontal direction.

Next, the sensing control lines SSCL may be formed at regular intervals to be parallel to the scan control lines SCL. In addition, the scan control line and the sensing control line may be formed as a single line.

Next, the data lines DL are arranged to have a predetermined interval along the first direction, i.e., the longitudinal direction, of the panel 100 so as to cross the scan control line SCL and the sensing control line SSCL, .

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

The red subpixel R, the white subpixel W, the green subpixel G and the blue subpixel B in the panel 100) One unit pixel 120 is formed, as shown in FIG. In this case, one sensing line is formed in 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 is d / 4.

In other words, the data lines are formed in the first direction (vertical direction) of the panel 100, the sensing lines SL are formed in parallel with the data lines, SL are connected to four sub-pixels 110 constituting each unit pixel 120 formed on one horizontal line, as shown in FIG. 6 shows two unit pixels 120 composed of a red subpixel R, a white subpixel W, a green subpixel G, and a blue subpixel B, respectively.

Next, the first driving power supply line PLA may be formed at regular intervals to be parallel to the data lines DL. Here, the first driving power line PLA may be spaced apart from the sensing line SL at regular intervals. The first driving power supply line PLA is connected to a driving power supply unit (not shown) and supplies a first driving power supply EVDD supplied from a driving power supply unit (not shown) to each pixel P.

The second driving power line PLB is formed on the entire surface of the panel 100 or connected to the data lines DL1 to DLd or the scan control lines SL1 to SLk, Or may be formed at regular intervals to be parallel to each other. The second driving power supply line supplies a second driving power (EVSS) supplied from a driving power supply unit to each pixel P. Alternatively, the second driving power supply line may be electrically grounded to a case (or a cover) of a metal material constituting the organic light emitting display. In this case, (Ground).

Lastly, each of the plurality of subpixels (P) 110 is formed for each pixel region defined by each of the scan control lines (SCL) and the data lines (DL1 to DLd), which intersect with each other.

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

The pixel driving circuit PDC includes a first switching transistor Tsw1, a second switching transistor Tsw2, a driving transistor Tdr, and a capacitor Cst. The transistors Tsw1, Tsw2, and Tdr may be a thin film transistor (TFT), such as an a-Si TFT, a poly-Si TFT, an oxide TFT, and an organic TFT.

The first switching transistor Tsw1 is switched by the first scan pulse SP1 and outputs a data voltage Vdata supplied to the data line DL. 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 electrode connected to a gate electrode of the driving transistor Tdr lt; RTI ID = 0.0 > d1. < / RTI >

The second switching transistor Tsw2 is switched by the second scan pulse SP2 to apply 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 Supply. To this end, the second switching transistor Tsw2 includes a gate electrode connected to an adjacent sensing control line SSCL, a first electrode connected to an adjacent sensing line SL and a second electrode connected to a second node n1 .

The capacitor Cst includes electrodes connected between the gate electrode of the driving transistor Tdr and the first electrode, that is, the first and second nodes n1 and n2. 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 charges the difference voltage of the voltage supplied to the first and second nodes n1 and n2 according to the switching of the first and second switching transistors Tsw1 and Tsw2, And switches the driving transistor Tdr according to the voltage.

The driving transistor Tdr controls the amount of current flowing from the first driving power supply line PLA to the organic light emitting diode OLED by being turned on by the voltage of the capacitor Cst. The driving transistor Tdr includes a gate electrode coupled to the first node n1, a first electrode coupled to the second node n2, and a second electrode coupled to the first driving power line PLA. do.

The organic light emitting diode OLED emits light having a luminance corresponding to the data current Ioled by the data current Ioled supplied from the driving transistor Tdr. For this, the organic light emitting diode OLED includes a first electrode (for example, an anode electrode) connected to the second node n2, that is, a first electrode of the driving transistor Tdr, An organic layer (not shown) and a second electrode (e.g., a cathode electrode) connected to the organic layer. The second electrode of the organic light emitting diode may be the second driving power supply line PLB formed on the organic layer or may be additionally formed on the organic layer to be connected to the second driving power supply line PLB.

In the above description, the structure of the subpixel 110 for performing external compensation has been described with reference to FIG. 7. However, the subpixel 110 may be formed in various structures in addition to the structure shown in FIG. 7 .

For example, the external compensation is a method of calculating the amount of change in threshold voltage or mobility of the driving transistor Tdr formed in the subpixel 110, and calculating the amount of change of the data voltage supplied to the unit pixel It means to vary the size. Therefore, the structure of the sub-pixel 110 can be changed into various forms so that the threshold voltage or the variation amount of the mobility of the driving transistor Tdr can be calculated.

The method of calculating the amount of change in threshold voltage or mobility of the driving transistor Tdr using the subpixel 110 for external compensation is also variously changed according to the structure of the subpixel 110 .

More specifically, the present invention relates to an organic light emitting diode (OLED) display device performing external compensation, and more particularly, the sensing is performed at the turn-off time, and the color of the sub-pixels sensed is changed every sensing period.

In this case, the structure of the subpixel for external compensation and the method of performing the external compensation may be composed of various subpixel structures and various external compensation methods currently proposed for external compensation. For example, the structure of the subpixel for external compensation and the method of performing external compensation are disclosed in Japanese Patent Laid-Open Nos. 10-2013-0066449, 10-2014-0066830, and 10 -2014-0074662, and the like can be applied, and also the application number 10-2013-0150057 and the application number 10-2013-0149213 filed by the present applicant And the like may be applied.

That is, the specific structure of the subpixel for performing external compensation and the specific method of external compensation are outside the scope of the present invention. Thus, an example of a subpixel for external compensation has been briefly described with reference to FIG. 7, and an external compensation method is also briefly described below.

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

The sensing mode is performed at each blank time. The period during which the sensing mode is performed is referred to as a sensing period. In the sensing mode, sensing is performed sequentially for each horizontal line. In the sensing mode, an external compensation value for correcting the characteristic change of the driving transistor Tdr is calculated. In this case, the panel driver changes the order of the colors of the sub-pixels sensed during the sensing period.

In the display mode, an image is output to the panel 100. In the display mode, the input image data is converted into the compensated image data using the external compensation value, and the compensated data voltage corresponding to the compensated image data is supplied to the panel through the data line. The input image data corresponding to the subpixels for which no external compensation is required are rearranged into general image data, then converted into a general data voltage, and supplied to the panel 100 through the data lines.

The panel driving unit may control a characteristic change of the driving transistor Tdr included in each subpixel P through the first through kth sensing lines SL1 through SLk in the sensing mode, Threshold voltage and / or mobility) to generate sensing data (Sdata) including characteristic information of the driving transistor.

The panel driver calculates the external compensation value based on the sensing data Sdata and uses the external compensation value to calculate input image data Ri, Gi, Bi input from an external system (not shown) And generates compensated image data. The panel driver converts the compensated image data (DATA) into a data voltage and supplies the data voltage to the corresponding sub-pixel (P).

For example, the panel driver may drive each of the driving transistors Tdr through each of the sensing lines SL1 to SLk in order to individually compensate for a characteristic change of the driving transistors Tdr included in each subpixel P, And compensates the input image data Ri, Gi, Bi using the characteristic variation amount of each of the sensed driving transistors Tdr, and converts the compensated compensated image data into compensated data voltages To each sub-pixel (P).

When the sensing period comes, the panel driving unit performs sensing for external compensation for each horizontal line of the panel 100, collects sensing data including characteristic information of the sub pixels 110, A sensing unit 410 for changing the order of the colors of the subpixels to be sensed, a calculation unit 410 for determining a characteristic change of each subpixel 110 using the sensing data and calculating an external compensation value, When a turn-off signal is received from the system (not shown), the controller 320 transmits a control signal to the sensing unit 320 to drive the sensing unit 320. When a turn-on signal is received from the external system, A control unit 400 for rearranging the input image data and outputting the rearranged output image data by using the output image data, And a scan driver for supplying a first scan pulse SP1 and a second scan pulse SP2 to the scan control lines SCL and the sense control lines SSCL, And a gate driver 200. The sensing unit 320 may be formed in the data driver 300 or independently of the data driver 300. Hereinafter, an organic light emitting display according to an embodiment of the present invention will be described with reference to the case where the sensing unit 320 is included in the data driver 300 as shown in FIG. In this case, the data driver 300 may include a data voltage output unit 310 for supplying various data voltages to the panel and the sensing unit 320, as shown in FIG. That is, the data voltage output unit 310 is the same as the data driver 300, but when the sensing unit 320 is included in the data driver 300, And a data voltage output unit 310. However, the panel driving unit, which is applied to the organic light emitting display according to the present invention, may have various structures other than the structures described below.

The control unit 400 controls the gate driver 200 and the gate driver 200 based on a timing control signal GCS for controlling the driving of the gate driver 200 based on a timing synchronization signal TSS input from an external system And a data control signal (DCS) for controlling the driving of the data driver 300. [

In addition, in the sensing mode in which sensing for external compensation is performed, the controller 400 transmits sensing image data to be supplied to the data driver 300 as subpixels formed on a horizontal line where external compensation is performed . The sensing for the external compensation can be performed at various timings. Hereinafter, the present invention will be described with reference to the case where the external compensation is performed at the turn-off time as described above. The controller 400 calculates the external compensation value based on the sensing data Sdata provided from the data driver 300 in the sensing mode and stores the external compensation value in the memory 450. The memory 450 may be included in the controller 400 or may be independently formed outside the controller 400. A specific method for the controller 400 to perform sensing for external compensation will be described in detail below with reference to the drawings.

In the display mode in which an image is output, the controller 400 controls the input image data to be output to the external device using the external compensation value according to a calculation unit control signal transmitted from the calculation unit 410, And converts the input image data into general image data by rearranging the input image data without external compensation.

4, the control unit 400 may use the timing synchronization signal transmitted from the external system (not shown) to input the input image data transmitted from the external system (GCS), the data control signal (DCS), and the data control signal (DCS) using the timing synchronization signal, a data alignment unit 430 for rearranging the data signals and supplying the rearranged output image data to the data driver 300, A control signal generation unit 420 for generating a power control signal PCS, a calculation unit 410 for determining a characteristic change of each subpixel 110 using the sensing data and calculating an external compensation value, A memory 450 for storing an external compensation value, and various output image data generated by the data arrangement unit 430 and various control signals generated by the control signal generator 420 Wherein the call comprises a data driver 300 or the output unit 440 for output to the gate driver 200.

The calculating unit 410 determines the characteristic change of each subpixel using the sensing data, and calculates the external compensation value. For example, the calculation unit 410 senses a change in the characteristics of the driving transistor formed in the sub-pixel using the sensing data (Sdata) received from the sensing unit 320 in the sensing mode, According to the characteristic change, the external compensation value may be calculated and the external compensation value may be stored in the memory 450. The method for calculating the external compensation value by the calculation unit 410 may be applied to the methods described in the above-mentioned patent publications and application documents filed by the present applicant. That is, the calculating unit 410 may calculate the external compensation value using various methods that are currently disclosed or described in the application specification filed by the present applicant. Therefore, a detailed description thereof will be omitted. The calculation unit 410 may be formed independently of the control unit 400 or may be formed in the control unit 400 as shown in FIG. Hereinafter, the present invention will be described as an example in which the calculation unit 410 is formed in the control unit 400. [

In the display mode, the data sorting unit 430 rearranges the input image data according to the structure of the subpixels 110, and then supplies the rearranged output image data to the data driver 300. In particular, the data arrangement unit 430 may correct the input image data using the external compensation value.

For example, in a display mode in which an image is output, when the input image data corresponding to a sub-pixel for which external compensation is not required is received, the data sorting unit 430 rearranges the input image data, And generates compensation image data by compensating the input image data using the external compensation value when the input image data corresponding to the subpixel requiring external compensation is received.

That is, in the display mode, when the external compensation for the input image data is requested, the data alignment unit 430 converts the input image data into the compensation image data using the external compensation value, If external compensation for data is not required, the input image data is rearranged according to the structure of the panel and converted into the general image data.

Accordingly, the data sorting unit 430 generates the compensated image data and the general image data in the display mode. The compensated image data and the general image data are generically referred to as output image data.

The control signal generator 420 generates various control signals required in the present invention. In particular, when the turn-off signal is received from the external system, the control signal generator 420 transmits the turn-off signal to the sensing unit 320, or transmits the turn-off signal to the sensing unit 320 320 and may transmit the control signal to the sensing unit 320. However, the turn-off signal may be transmitted to the sensing unit 320 directly.

The control signal generator 420 may generate a control signal for defining the sensing sequence for the four subpixels formed in the unit pixel and transmit the control signal to the sensing unit 320. According to the control signal, the sensing unit 320 may change the order of colors of the subpixels to be sensed for each sensing period.

In the first exemplary embodiment of the present invention, the control signal generator 420 may be configured such that the sensing unit 320 first senses white sub-pixels at every sensing period to collect white sensing data, And then transmits the generated control signal to the sensing unit 320. The sensing unit 320 may generate a control signal for sensing the blue sensing data.

In this case, the control signal generation unit 420 may include a step of sensing the white sub-pixels between the sensing unit 320 and sensing the blue sub-pixels, And transmits the control signal to the sensing unit 320. The sensing unit 320 may generate a control signal for performing at least one more time.

In the second exemplary embodiment of the present invention, the control signal generator 420 generates a control signal for sequentially changing the order of the colors to be sensed at every sensing period, Unit 320 of FIG.

In this case, the control signal generator 420 senses the white subpixels before sequentially sensing the subpixels by sequentially changing the order of the hues every sensing period And generate a control signal for collecting the white sensing data, and transmit the control signal to the sensing unit 320.

However, a control signal for driving the sensing unit 320 as described above is not necessarily transmitted to the sensing unit 320. For example, the sensing unit 320 may store a control signal for driving the sensing unit 320 according to the first embodiment or the second embodiment. In this case, when the signal corresponding to the turn-off signal or the turn-off signal is transmitted from the controller 420, the sensing unit 320 is driven according to the first embodiment or the second embodiment, The sensing data can be collected.

In addition, the first embodiment or the second embodiment may be implemented by the sensing image data generated from the data arrangement unit 430. For example, when the sensing period comes, the controller 400 generates the sensing image data corresponding to the first or second exemplary embodiment and outputs the sensed image data to the data voltage output unit 310).

As described above, when one horizontal line is sensed during the sensing period, only the subpixels corresponding to one color among the unit pixels formed in the horizontal line are simultaneously sensed. In this case, only the sub-pixels to be sensed can be supplied with the sensing data voltage corresponding to the sensing image data. Therefore, the first embodiment or the second embodiment can be implemented by controlling the order of the sensing image data.

The memory 450 stores the external compensation value transmitted from the calculation unit 410 and transmits the external compensation value to the data arrangement unit 430 as described above.

The memory 450 may store various information such that the first embodiment or the second embodiment is implemented. For example, in the memory 450, information that matches the order of the colors to be sensed may be stored, or sensing image data that is matched with the order of the colors to be sensed may be stored.

The gate driver 200 sequentially generates a first scan pulse SP1 in response to a gate control signal GCS supplied from the controller 400 and sequentially supplies the first scan pulse SP1 to the scan control lines SCL. And sequentially generates a second scan pulse SP2 in response to the gate control signal GCS and sequentially supplies the second scan pulse SP2 to the sensing control lines SSCL. Here, the gate control signal GCS may include a start signal, a plurality of clock signals, and the like.

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

Lastly, the data driver 300 is connected to the data lines DL1 to DLd and the sensing lines SL1 to SLd and outputs a sensing mode or a display mode according to a control signal transmitted from the controller 400. [ . 5, when the data driver 300 includes the data voltage output unit 310 and the sensing unit 320, the data voltage output unit 310 outputs the data voltage DL to the data line DL, And the sensing unit 320 is connected to the sensing lines SL.

When the control signal corresponding to the turn-off signal or the turn-off signal is received, the sensing unit 320 supplies the reference voltage Vref to each of the sensing lines SL1 to SLk during the sensing period A sensing transistor for sensing a characteristic change of the driving transistor Tdr included in the subpixels P formed on one horizontal line to receive the sensing data Sdata by receiving a signal corresponding to the reference voltage, .

The sensing unit 320 provides the generated sensing data Sdata to the controller 400. [

To this end, the subpixels may be configured as shown in FIG.

For example, one sensing line SL is provided for each unit pixel 120 including R, G, B, and W subpixels 110 among the subpixels formed on one horizontal line Respectively. Accordingly, when one sensing data voltage is supplied through each sensing line SL, the sensing data for one subpixel of each unit pixel 120 is transmitted to the sensing unit 320. [

In the first embodiment of the present invention, the sensing unit 320 first senses white subpixels by collecting white sensing data every sensing period, senses blue subpixels at the latest, collects blue sensing data can do.

For example, during a first sensing period generated by the first turn-off signal, the sensing unit 320 may include a white sub-pixel W, a green sub-pixel G, The red subpixel R and the blue subpixel B in this order.

During the second sensing period generated by the second turn-off signal, the sensing unit 320 outputs the white subpixel W, the red subpixel R, and the green subpixel R G) and a blue sub-pixel (B). That is, in the second sensing period, the sensing sequence of the red subpixel and the green subpixel may be changed in comparison with the first sensing period. During the second sensing period generated by the second turn-off signal, the sensing unit 320 generates a white sub-pixel W, a green sub-pixel G, and a red sub- Pixel R and blue sub-pixel B in this order. That is, the sensing may be performed in the same order as the sensing sequence in the first sensing period.

 As mentioned in the prior art, even if the degradation rates are the same, the luminance of the white subpixels is the greatest dropping and the luminance of the blue subpixels is the smallest. Thus, the need for external compensation for white subpixels is the highest and the need for external compensation for blue subpixels is lowest. Therefore, in the first embodiment, in all the sensing periods, the white subpixel W is sensed with the highest priority and the blue subpixel B is sensed last. Further, in the first embodiment, in every sensing period, between the sensing period for the white subpixels and the sensing period for the blue subpixels, the green subpixel and the red subpixel may be sensed in the same order, The sensing order of the green subpixel and the red subpixel may be changed.

In the first embodiment, the sensing unit 320 senses the white sub-pixels between sensing the white sub-pixels and sensing the blue sub-pixels at least one or more times And collect the sensing data.

For example, in the first sensing period, the sensing unit 320 may sense the white subpixel, the green subpixel, the red subpixel, the white subpixel, and the blue subpixel in this order. In the second sensing period, , A white subpixel, a green subpixel, a white subpixel, a red subpixel, and a blue subpixel.

In addition to the above sequence, the sensing unit 320 may sense the subpixels in various orders between the sensing period of the white subpixels and the sensing period of the blue subpixels.

In the above description, the blue subpixels are described as being sensed at the latest, but the red subpixels may be sensed at the latest.

In the second exemplary embodiment of the present invention, the sensing unit 320 sequentially collects sensed data by sequentially changing the order of colors to be sensed at every sensing period.

For example, the sensing unit 320 may sense the white subpixel, the green subpixel, the red subpixel, and the blue subpixel in the order of the white subpixel, the red subpixel, and the blue subpixel in each unit pixel during the first sensing period, The red subpixel, the blue subpixel, the white subpixel, and the blue subpixel in each unit pixel in the order of the green subpixel, the red subpixel, the blue subpixel, and the white subpixel in each unit pixel, Pixel and a green subpixel, and during a fourth sensing period, in each unit pixel, the blue subpixel, the white subpixel, the green subpixel, and the red subpixel may be sensed in this order. According to the second embodiment, no case occurs in which only one color subpixel is intensively sensed or subpixels of either color are not consecutively sensed.

In the second embodiment, the sensing unit 320 senses white sub-pixels and collects sensing data before sequentially sensing the sub-pixels by sequentially changing the order of the hues every sensing period .

For example, the sensing unit 320 may first sense the white subpixels during the first sensing period to the fourth sensing period to collect sensing data. As described above, the luminance of the white subpixel drops most by the deterioration. Thus, in order to more fully perform the external compensation for the white subpixel, the white subpixel may be preferentially sensed at every sensing period, as described above.

The change of the sensing sequence as described above may be changed by various methods, but may be changed in particular by the order of the sensing data transmitted from the controller 400 to the data output unit 310.

For example, when the sensing period comes, the controller 400, in particular, the data arranging unit 430 generates the sensing image data corresponding to the first embodiment or the second embodiment, And transmit the sensed image data to the data voltage output unit 310.

For example, as in the first embodiment, when the white subpixel is preferentially sensed in every sensing period, the controller 400 is formed on a horizontal line to be sensed when the sensing period arrives White sensing image data corresponding to white subpixels among the subpixels, and transmits the generated white sensing image data to the data output unit 310.

While the data output unit 310 supplies the white sensing data voltages corresponding to the white sensing image data to the white sub-pixels of the horizontal line, the sensing unit 320 may include the unit pixels 120 To a sensing voltage or a reference voltage. Thereafter, the sensing unit 320 collects sensing data through the sensing lines, and transmits the sensed data to the calculating unit 410. In this case, the sensing data are white sensing data collected from the white subpixels.

The controller 400 performs the above process for all the white subpixels formed on the panel 100. [

When all the white subpixels are sensed, the controller 400 generates sensing image data corresponding to the next color and transmits the sensed image data to the sensing unit 320. The sensing unit 320 senses Sensing data may be collected from subpixels corresponding to the color of the turn.

The control unit 400 and the sensing unit 320 repeatedly perform the above process so that all the subpixels are sensed in the order as described in the first embodiment or the second embodiment, .

For this, the data voltage output unit 310 converts the output image data transmitted from the control unit 400, that is, the sensing image data, into a sensing data voltage and supplies the sensed data voltage to the data line in the sensing mode . The change in the characteristics of the driving transistor formed in the sub pixel supplied with the sensing data voltage is transmitted to the sensing unit 320 through the sensing line SL.

In the display mode, the data voltage output unit 310 outputs the output image data (image data) supplied from the control unit 400 on a horizontal line basis using a plurality of reference gamma voltages supplied from a reference gamma voltage supply unit DATA) into data voltages and supplies them to the corresponding data lines DL1 to DLd.

That is, the data voltage output unit 310 samples the output image data DATA of each subpixel P input in units of one horizontal line according to the data control signal DCS, The gamma voltage corresponding to the gray level value of the sampling data is selected as the data voltage and supplied to the data line DL of the corresponding sub pixel P.

The output image data transmitted to the data voltage output unit 310 in the display mode is the compensated image data or the general image data.

The sensing unit 320 senses voltage or current of each of the sensing lines SL1 to SLk in the sensing mode and generates sensing data Sdata corresponding to the sensing voltage or current to control the controller 400 ). For this, the sensing unit 320 may include an analog-to-digital converter for converting the sensing voltage or current transmitted from the sensing lines to digital to generate the sensing data (Sdata).

The sensing unit 320 performs the sensing process at a turn-off time at which the organic light emitting display device is turned off.

8 is a flowchart illustrating a method of driving an OLED display according to an exemplary embodiment of the present invention. FIG. 9 is a graph showing luminance characteristics of an organic light emitting diode display according to an embodiment of the present invention. FIG. 9 (a) is a graph showing an example of a state where a threshold voltage increases with time, and FIG. 9 FIG. 4 is a graph illustrating an embodiment in which the luminance of sub-pixels is compensated by the invention.

First, when the electronic product on which the OLED display according to the present invention is mounted is turned off, a turn-off signal is transmitted from the external system for driving the electronic product to the controller 400 of the OLED display . When the turn-off signal is received, the sensing unit 300 is driven according to the control of the controller 400 to collect sensing data (S602).

That is, during the sensing period, the sensing unit 320 performs sensing for external compensation for each horizontal line of the panel 100, and collects sensing data including characteristic information of the subpixels. In particular, the sensing unit 3200 may change the order of the colors of the sub-pixels sensed for each sensing period according to the first embodiment or the second example described above.

In the unit pixel 120, one sensing line is formed as shown in FIG. That is, while the reference voltage is applied to one sensing line, a data voltage is supplied only to one of the pixels forming the unit pixel, Can be detected.

In this case, the order in which the subpixels are sensed in each unit pixel may be variously changed. However, the order can be set such that the white subpixel is the most preferentially sensed or the most sensible.

Also, the order can be set so that the blue subpixels can be sensed most recently, or least sensed. In this case, when the turn-off time advances normally, since the blue sub-pixel to be sensed most later is also always sensed, the sensing number of the white sub-pixel to be sensed first and the white sub-pixel to be sensed last are the same . However, when the turn-off time is abnormally terminated, for example, when the power supply line of the electronic product is disconnected from the power supply portion at the turn-off time, or is turned on immediately after the electronic product is turned off, The white sub-pixel to be sensed can always be sensed, but the blue sub-pixel to be sensed last may not be sensed.

However, according to the present invention, even if the turn-off time is abnormally terminated, white subpixels with the greatest change in luminance performance due to deterioration can be sensed and compensated in the first order, Can be improved. Therefore, as shown in FIG. 9, the luminance of the white subpixel can be kept constant even if time passes. Accordingly, the quality of the organic light emitting display device can be maintained constantly.

In addition, according to the present invention, the remaining subpixels except the white subpixel can be sensed in different orders every sensing period. Therefore, even if the turn-off time is abnormally terminated, the remaining sub-pixels except the white sub-pixel may be sensed. Therefore, as shown in FIG. 9, the luminance of the red subpixel, the green subpixel, and the blue subpixel can be maintained constant over time. Accordingly, the quality of the organic light emitting display device can be maintained constantly.

Next, the calculating unit 410 may calculate the external compensation value using the sensing data (S606). As described above, the specific method for calculating the external compensation value can be applied to the methods described in the open patent documents and various patent documents filed by the present applicant.

In this case, the calculating unit 410 may calculate the external compensation value at the turn-off time, or may calculate the external compensation value at the turn-on time that comes after the turn-off time.

In the former case, when the white subpixels are sensed and the white sensing data is collected at the turn-off time, the sensing data of the subpixels of the other colors are collected, The external compensation value can be calculated. The calculating unit 410 may calculate the external compensation value for the subpixels corresponding to another color after the external compensation value for the white subpixels is calculated during the turnoff time have.

In the latter case, the calculating unit 410 may calculate the external compensation value for the subpixels using the sensing data collected at the turn-off time at the turn-on time that comes after the turn-off time have. In this case, if the turn-off time ends abnormally and only the sensing data for the subpixels corresponding to a specific color among the subpixels are stored in the memory 450, Only the external compensation value for the subpixels corresponding to the specific color stored in the memory 450 can be calculated.

Next, when the input image data corresponding to a sub-pixel for which external compensation is not required is received in the display mode coming after the turn-on time, the data sorting unit 430 rearranges the input image data, And generates image data.

In addition, when the input image data corresponding to a sub-pixel requiring external compensation is received, the data arrangement unit 430 compensates the input image data using the external compensation value to generate the compensated image data.

The method of generating the general image data by rearranging the input image data or generating the compensated image data by adding the specific compensation value to the input image data can be applied as it is in the conventional method. Therefore, a detailed description thereof will be omitted.

Lastly, the data driver 300 converts the general video data into a general data voltage, converts the compensated video data into a compensated data voltage, supplies the data to the data lines formed on the panel, , And an image is displayed through the panel (100).

According to the present invention, even if the threshold voltage or mobility of the driving transistor formed in the sub-pixels formed on the panel 100 is changed, the panel 100 can be normally driven.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: panel 200: gate driver
300: Data driver 400: Timing controller
110: subpixel 120: unit pixel
410: Calculator 420: Control signal generator
430: Data sorting unit 440: Output unit
450: Memory

Claims (5)

A subpixel constituting unit pixels is formed for each horizontal line, and a sensing for external compensation is formed for each horizontal line;
When the sensing period arrives, sensing for external compensation is performed for each horizontal line of the panel, and the sensing data including the characteristic information of the sub pixels is collected, and the order of the colors of the sub pixels to be sensed Sensing unit;
A calculating unit for determining a characteristic change of each subpixel using the sensing data and calculating an external compensation value;
And when the turn-off signal is received from the external system, the control unit transmits the control signal to the sensing unit to drive the sensing unit. When the turn-on signal is received from the external system, the input image data is rearranged using the external compensation value, Outputting the output image data; And
And a data driver for converting the output image data into an output data voltage and supplying the output data voltage to the data lines formed on the panel. The method according to claim 1,
The sensing unit includes:
Wherein the blue subpixels or the red subpixels are sensed at the earliest sensing the white subpixels to collect the white sensing data at every sensing period. 3. The method of claim 2,
The sensing unit includes:
Sensing the white subpixels and sensing the white subpixels during the sensing of the blue subpixels or the red subpixels at least one more time. The method according to claim 1,
The sensing unit includes:
And sequentially changes the order of the colors to be sensed in every sensing period. 5. The method of claim 4,
The sensing unit includes:
Wherein the sensing unit collects white sensing data by sensing white subpixels before sequentially sensing the subpixels by sequentially changing the order of the colors every sensing period.

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