KR102473136B1 - Compensation method for organic light emitting display device - Google Patents

Abstract

The compensation method of the organic light emitting display device of the present invention first measures the threshold voltage value by sampling, then measures all the threshold voltage values in a shorter time and adds an offset by the gap of the sampling measurement to obtain high-speed It is characterized by proceeding with external compensation.
Accordingly, the present invention provides an effect capable of reducing a tact time for compensation.

Description

Compensation method of organic light emitting display device {COMPENSATION METHOD FOR ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present invention relates to a compensation method for an organic light emitting display device, and more particularly, to a compensation method for an organic light emitting display device that can be applied to compensation for image quality inspection after a cell process and/or compensation in a module process. .

In general, the electronic display device is increasing its importance as a means of transmitting visual information, and at the same time, the size of the industry is expanding in the realization of the information society. Diversification of information represented by the word multimedia makes the need for electronic display devices clearer. At the same time, the demand for electronic display devices is becoming stronger with a large screen, high resolution, excellent visibility, and economical efficiency. In particular, low voltage and low power consumption are required as essential conditions for portable information devices.

As one of these electronic display devices, the liquid crystal display (LCD), which has expanded its application market due to its thinness, light weight, and low power consumption, is not only rapidly expanding its demand, but also recently as consumers' living standards have improved. High-definition products with increasingly larger sizes are required.

As another electronic display device, an organic light emitting display device is superior in a viewing angle and a contrast ratio compared to a liquid crystal display device because it is a self-luminous type. In addition, since a backlight is not required, it is possible to be lightweight and thin, and is advantageous in terms of power consumption. In addition, there are advantages in that DC low voltage driving is possible and response speed is fast.

An organic light emitting display device includes an organic light emitting diode.

An organic light emitting diode includes an anode as a pixel electrode, a cathode as a common electrode, and an organic layer formed therebetween.

At this time, the organic layer includes a hole transport layer, an electron transport layer, and a light emitting layer interposed between the hole transport layer and the electron transport layer.

When positive (+) and negative (-) voltages are applied to the anode and cathode, respectively, in the organic light emitting diode configured as described above, holes that have passed through the hole transport layer and electrons that have passed through the electron transport layer are moved to the light emitting layer to generate excitons. form In addition, when the exciton transitions from an excited state to a ground state, that is, a stable state, light of a predetermined wavelength is generated.

An organic light emitting display device displays an image by arranging sub-pixels on which organic light emitting diodes having the above-described structure are formed in a matrix form and selectively controlling the sub-pixels with a data voltage and a scan voltage.

At this time, the organic light emitting display device is divided into a passive matrix type and an active matrix type using a thin film transistor as a switching element. Among them, the active matrix method selects a sub-pixel by selectively turning on a thin film transistor, which is an active element, and maintains light emission of the sub-pixel with a voltage maintained in a storage capacitor.

In general, for large-sized high-definition products such as TV models, compensation for image inspection in the auto probe process is in progress. That is, in order to realize a uniform screen before image inspection, a process of measuring/compensating the threshold voltage for each pixel is performed in the auto probe process.

1 is a flowchart sequentially showing a compensation method of a general organic light emitting display device.

At this time, FIG. 1 shows a compensation method for an ultra high definition television (UHD Television) having a pixel count of 3840×2160 as an example.

Referring to FIG. 1 , for example, an external compensation process takes about 2 s to prepare for sensing (S110).

Next, sensing is performed for all pixels with a sensing time of 20 ms, for example (S120).

In this case, the total sensing time is about 173 s (sensing time (20 ms) × number of gate lines (2160) × number of colors (4)).

Next, the threshold voltage value measured by total sensing is input to an external computer through communication, and it takes about 52 s (S130).

Next, the measured threshold voltage value is recalled/processed and input to a memory such as a double data rate (DDR) SDRAM (S140, S150).

At this time, it takes about 5 s to calculate the threshold voltage value, and about 28 s to input the memory, so that the entire external compensation process takes about 260 s.

As such, sensing time consumes the most time in the external compensation process, and in the past, sensing time has been reduced from 60ms to 30ms and 20ms. However, when the sensing time is reduced to 20 ms or less, defects appearing at 20 ms are not detected, resulting in poor defect determination consistency. That is, as the sensing time decreases, the measured threshold voltage value decreases, so the voltage to be compensated increases, and the screen is lit differently from the screen compensated for 30 ms, and the defect appears differently.

The present invention is to solve the above problems, and an object of the present invention is to provide a compensation method for an organic light emitting display device capable of performing external compensation at high speed.

Other objects and features of the present invention will be described in the following constitution of the invention and claims.

In order to achieve the above object, a compensation method of an organic light emitting display device according to an embodiment of the present invention includes calculating an offset value using an average value of threshold voltages measured through sampling sensing and total sensing; and It may be configured to include the step of correcting the calculated offset value by adding it to the threshold voltage measured by performing the total sensing.

In this case, the sampling sensing is performed for some gate lines, and the total sensing is performed for all pixels in a shorter sensing time than the sampling sensing.

The sampling sensing may proceed with a sensing time of 20 ms.

The sampling and sensing may be performed by selecting some gate lines in a partial region among all gate lines.

The total sensing may proceed with a sensing time of 5 ms.

After performing the sampling and sensing, a step of calculating an average value of the measured threshold voltages may be further included.

In this case, after performing the total sensing, calculating an average value of the measured threshold voltages may be further included.

In this case, the step of calculating the offset value may be calculated by subtracting the average value of the threshold voltages measured through the total sensing from the average value of the threshold voltages measured through the sampling sensing.

A step of performing a lighting test after performing external compensation by correcting the threshold voltage may be further included.

In this case, the lighting inspection may be performed in an auto probe process for quality inspection after a cell process or may be performed in a compensation process after attaching a driver IC during a module process.

As described above, the compensation method of the organic light emitting display device according to an embodiment of the present invention first samples and measures the threshold voltage value and then measures all the threshold voltage values in a shorter time to offset by the gap of the sampling measurement It is characterized in that external compensation is performed at high speed by adding an off-set.

Accordingly, the present invention provides an effect of reducing the existing external compensation tak time by about 50% from about 260s to 131s.

1 is a flowchart sequentially showing a compensation method of a general organic light emitting display device;
2 schematically shows an organic light emitting display device according to an embodiment of the present invention;
3 is a diagram showing a sensing principle for extracting a threshold voltage change of a driving TFT as an example;
4 is a diagram showing a sensing principle for extracting a change in mobility of a driving TFT as an example;
5 is a flowchart sequentially showing an inspection process of an organic light emitting display device according to an embodiment of the present invention.
6 is a diagram showing an external compensation system of an organic light emitting display device according to an exemplary embodiment of the present invention.
7 is a flowchart sequentially showing a compensation method of an organic light emitting display device according to an embodiment of the present invention.
8 is a graph showing results of sampling sensing as an example;
9 is a graph showing results of total sensing as an example;
10 is a graph showing a result of applying an offset according to sampling sensing to a result of total sensing as an example.
11A to 11D are graphs showing correlation coefficients according to changes in sensing time as examples.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of a compensation method for an organic light emitting display device according to the present invention will be described in detail so that those skilled in the art can easily implement it.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various forms different from each other, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention pertains. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification. The sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of explanation.

When an element or layer is referred to as “on” or “on” another element or layer, it includes both cases where another element or layer is intervening as well as directly on another element or layer. do. On the other hand, when an element is referred to as “directly on” or “directly on”, it indicates that no other element or layer is intervening.

The spatially relative terms "below, beneath", "lower", "above", "upper", etc., refer to one element or component as shown in the drawing. It can be used to easily describe the correlation between and other elements or components. Spatially relative terms are to be understood as terms encompassing different orientations of elements in use or operation in addition to the directions shown in the figures. For example, when flipping elements shown in the figures, elements described as “below” or “beneath” other elements may be placed “above” the other elements. Thus, the exemplary term “below” may include directions of both below and above.

Terminology used herein is for describing the embodiments, and therefore is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, "comprise" and/or "comprising" means that a stated component, step, operation, and/or element is the presence of one or more other components, steps, operations, and/or elements. or do not rule out additions.

2 is a diagram schematically showing an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2 , an organic light emitting display device according to an embodiment of the present invention includes a display panel 110, a timing controller 111, a data driving circuit 112, a gate driving circuit 113, and a memory 116. can be provided

In the display panel 110, a plurality of data lines 114a, sensing lines 114b, and a plurality of gate lines 115 intersect, and pixels P are arranged in a matrix form at each intersection. . The gate lines 115 may include a plurality of first gate lines to which scan control signals are sequentially supplied and a plurality of second gate lines to which sensing control signals are sequentially supplied.

Each pixel P is connected to one of the data lines 114a, one of the sensing lines 114b, one of the first gate lines, and one of the second gate lines. can Each pixel P is connected to the data line 114a in response to the scan control signal input through the first gate line and connected to the sensing line 114b in response to the sensing control signal input through the second gate line. can

Each of the pixels P may receive a high potential driving voltage and a low potential driving voltage from a power generator (not shown).

The pixel P may include an organic light emitting diode (OLED) and a driving TFT for driving the OLED. The driving TFT may be implemented as a p-type or as an n-type. Also, the semiconductor layer of the driving TFT may be made of amorphous silicon, polysilicon or oxide.

Each of the pixels P may operate differently during normal driving for realizing a display image and sensing driving for sensing a threshold voltage change value. The sensing drive of the present invention may be performed for a predetermined time during a power-on process or during a predetermined time during a power-off process. However, the present invention is not limited thereto.

The sensing drive may be performed by one operation of the data driving circuit 112 and the gate driving circuit 113 under the control of the timing controller 111 .

The data driving circuit 112 includes at least one data driver IC (Integrated Circuit). Although not shown, the data driver IC includes a plurality of digital-to-analog converters (hereinafter referred to as DACs) connected to each data line 114a, a plurality of sensing units connected to each sensing line 114b, and the sensing units selectively analog-to-analog converters. A mux unit connected to a digital converter (hereinafter referred to as ADC) and a shift register that sequentially turns on switches of the mux unit by generating a selection control signal may be provided.

During sensing operation, the DAC generates sensing data voltages under the control of the timing controller 111 and supplies them to the data lines 114a. Meanwhile, the DAC may generate data voltages for image display under the control of the timing controller 111 during normal driving and supply them to the data lines 114a.

Each sensing unit may be connected to the sensing line 114b one-to-one. Each sensing unit may supply a reference voltage to the sensing line 114b or a sensing voltage charged in the sensing line 114b to the ADC under the control of the timing controller 111 .

The ADC may convert a sensing voltage selectively input through the mux unit into a digital sensing value and transmit the converted digital sensing value to the timing controller 111 .

The gate driving circuit 113 may generate scan control signals suitable for sensing driving and normal driving under the control of the timing controller 111 and then supply the scan control signals to the first gate lines in a row-sequential manner. The gate driving circuit 113 may generate sensing control signals suitable for sensing driving and normal driving under the control of the timing controller 111 and then supply the sensing control signals to the second gate lines in a row-sequential manner.

The timing controller 111 operates the data driving circuit 112 based on timing signals such as a vertical sync signal (Vsync), a horizontal sync signal (Hsync), a dot clock signal (DCLK), and a data enable signal (DE). A data control signal DDC for controlling the timing and a gate control signal GDC for controlling the operation timing of the gate driving circuit 113 may be generated. The timing controller 111 separates normal driving and sensing driving based on predetermined reference signals (driving power enable signal, vertical synchronization signal, data enable signal, etc.), and generates a data control signal (DDC) and gate for each drive. A control signal GDC may be generated. In addition, the timing controller 111 may further generate related switching control signals CON to operate internal switches of each sensing unit according to normal driving and sensing driving.

The timing controller 111 may transmit first compensation data corresponding to the data voltage for sensing to the data driving circuit 112 during sensing driving. Here, the first compensation data reflects a compensation value capable of compensating for a change in the threshold voltage of the driving TFT sensed in the previous sensing period. The timing controller 111 may transmit the second compensation data RGB corresponding to the data voltage for image display to the data driving circuit 112 during normal driving. Here, a compensation value capable of compensating for a change in the threshold voltage of the driving TFT sensed in the previous sensing period is reflected in the second compensation data RGB.

The timing controller 111 may derive a threshold voltage change value of the driving TFT based on the digital sensing voltage Vsen transmitted from the data driving circuit 112 during sensing driving and store it in the memory 116 .

3 is a diagram showing a sensing principle for extracting a threshold voltage change of a driving TFT as an example.

4 is a diagram showing a sensing principle for extracting a change in mobility of a driving TFT as an example.

An active matrix type organic light emitting display device includes an organic light emitting diode (OLED) that emits light by itself, and has advantages such as fast response speed, high luminous efficiency, luminance, and viewing angle.

As described above, in the organic light emitting display device, pixels each including an OLED are arranged in a matrix form, and luminance of the pixels is adjusted according to a gray level of video data. Each of the pixels includes a driving TFT to control a driving current flowing through the OLED.

Electrical characteristics of the driving TFT, such as threshold voltage and mobility, are preferably designed identically in all pixels, but in reality, the electrical characteristics of the driving TFT are non-uniform for each pixel due to process conditions, driving environments, and the like. For this reason, the driving current according to the same data voltage is different for each pixel, and as a result, a luminance deviation occurs between the pixels. In order to solve this problem, an image quality compensation technology is implemented to reduce luminance non-uniformity by sensing characteristic parameters (threshold voltage, mobility) of a driving TFT from each pixel and appropriately correcting input data according to the sensing result.

Referring to FIG. 3, as an example, sensing method 1 for extracting a change in the threshold voltage (Vth) of the driving TFT (DT) operates the driving TFT (DT) in a source follower manner, and then the driving TFT (DT ) of the source voltage Vs as the sensing voltage Vsen, and based on the sensing voltage Vsen, the amount of change in the threshold voltage of the driving TFT DT can be detected.

The amount of change in the threshold voltage of the driving TFT is determined according to the magnitude of the sensing voltage Vsen, through which an offset value for data compensation is obtained. In this sensing method 1, the voltage Vgs between the gate and source of the driving TFT (DT) operated in the source follower method reaches a saturation state (ie, the current between the drain and source of the driving TFT (DT) is Since the sensing operation must be performed after the sensing operation is performed (when it becomes zero), the time required for sensing is long and the sensing speed is slow. This sensing method 1 is referred to as a slow mode sensing method.

Referring to FIG. 4, in the sensing method 2 for extracting the change in mobility (μ) of the driving TFT (DT), in order to define the current capability characteristics excluding the threshold voltage (Vth) of the driving TFT (DT), the driving TFT ( A constant voltage higher than the threshold voltage of the driving TFT (DT) (Vdata+X, where X is the voltage according to offset value compensation) is applied to the gate of the driving TFT (DT) to turn on the driving TFT (DT), and in this state, a constant The source voltage Vs of the driving TFT DT charged during the time is received as the sensing voltage Vsen. The amount of change in the mobility of the driving TFT is determined according to the magnitude of the sensing voltage Vsen, through which a gain value for data compensation is obtained. Sensing method 2 is characterized in that the time required for sensing is short and the sensing speed is fast because it is performed while the driving TFT is turned on. This sensing method 2 is referred to as a fast mode sensing method.

The slow mode sensing method requires a sufficient sensing period because the sensing speed is slow. That is, in the slow mode sensing method for sensing the threshold voltage of the driving TFT, an image is displayed during the first sensing period, that is, in response to a power off command signal from the user, so that the sensing time can be sufficiently allocated without being recognized by the user. It has no choice but to be performed from the end until the driving power is turned off. On the other hand, in the fast mode sensing method for sensing the mobility of the driving TFT, since the sensing speed is fast, the image is displayed during the second sensing period, that is, after the driving power is turned on in response to the power-on command signal from the user. It may be performed before the image display drive period or in vertical blank periods within the image display driving period.

The external compensation method according to the present invention may be performed when measuring the above-described slow mode sensing data.

In particular, the compensation method of the organic light emitting display device according to the present invention is characterized in that the total tak time for compensation is reduced by reducing the sensing time of the threshold voltage value by about 35% through sampling.

The external compensation method according to the present invention can be applied not only to an auto probe process for image quality inspection after a cell process, but also to a compensation process during a module process, that is, after attaching a driver IC.

Hereinafter, an auto probe inspection process after a cell process of an organic light emitting display device according to the present invention will be described in detail with reference to drawings.

5 is a flowchart sequentially showing an inspection process of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 5 , the display panel that has undergone the cell process may be loaded into a sub table of a predetermined auto probe inspection equipment (S210).

At this time, as an example, a display panel having a large size of 55 inches to 65 inches and a UD resolution of 3840×2160 is taken as an example.

For reference, UHD is also called '4K resolution' or 'UD resolution', and UHD is filmed at a resolution four times higher than FHD (Full HD) (3840 × 2160), so it is clear enough to make a normal screen feel like a stereoscopic image. do.

Next, the display panel loaded on the sub table is fixed in place by a clamp or the like (S220), and the ID of the display panel can be read by a radio frequency identification (RFID) reader or the like (S230).

Next, the display panel loaded on the sub table may be transferred to the work table for inspection (S240).

For example, the auto probe inspection equipment includes a work table for loading and aligning display panels of an organic light emitting display device, a work stage for seating the work table, a probe block for lighting inspection of display panels, and a block stage for mounting the probe block. can be configured to include However, the present invention is not limited thereto, and auto probe inspection equipment having various configurations may be used.

At this time, the display panel transported to the work table may be placed on the work table and aligned through a predetermined aligning unit (S250).

Then, through the auto probe inspection equipment, electrical signals are applied to a plurality of pads configured in the display panel of the organic light emitting display device to perform a lighting test. Specifically, lighting of the display panel, external compensation, and lighting by the inspector The inspection may proceed in order (S261, S262, S263; S260).

External compensation may be performed by measuring the threshold voltage of the driving TFT of each pixel through sensing and then inputting the deviation to the source voltage. After such compensation, a uniform image can be observed, so that a stain, PD (Point Defect), or threshold voltage value can be determined.

The display panel for which lighting inspection has been performed in this way may be unloaded for a subsequent process after being transported from the work table to the sub table (S270).

6 is a diagram showing an external compensation system of an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 6 , the external compensation system 200 according to an embodiment of the present invention is a basic environment for external compensation before proceeding with a lighting inspection, for example, a display panel 210 and a control printed circuit board (PCB). 220, a PC to OLED T-con (POT) 230, an interface PCB 240, and a PC 250 including software.

The control PCB 220 serves to transmit data to the source IC by adding a compensation value to the input image, and uses a large-capacity T-con (Timing controller) and multiple memories of NAND, DDR, and EEPROM to implement the compensation algorithm. can At this time, additional power is required for compensation and sensing operations.

The POT (230) serves to change the data received from the PC (250) into an LVDS format that the T-con can receive. etc. can be used.

The external compensation PC 250 is a communication board and is connected to the T-con of the control PCB 220 to measure the threshold voltage of the pixel using separate software.

7 is a flowchart sequentially showing a compensation method of an organic light emitting display device according to an embodiment of the present invention, and shows a method of implementing a 20 ms compensation screen with a 5 ms sensing time as an example.

At this time, FIG. 7 shows a compensation method for a UHD television having a pixel count of 3840×2160 as an example.

Referring to FIG. 7 , for example, an external compensation process may take about 2 s to prepare for sensing (S310).

Thereafter, sampling and sensing may be performed by selecting some gate lines in a partial region among all gate lines (S320).

For example, the threshold voltage may be measured by performing sampling sensing with a sensing time of 20 ms for 50 gate lines.

In this case, a sensing time of about 4 s is required, and the sensing time for all existing pixels is 20 ms × 2160 × 4, which takes about 173 s.

After sampling and sensing are performed, an average value of the measured threshold voltages may be calculated.

8 is a graph showing the results of sampling sensing as an example. Selecting 10 gate lines from 5 areas out of 2160 gate lines and performing sampling sensing with a sensing time of 20 ms for a total of 50 gate lines, the threshold voltage shows the result of the measurement.

In this case, in FIG. 8, the horizontal axis represents the gate line number, and the vertical axis represents the threshold voltage value.

Referring to FIG. 8 , as a result of performing sampling sensing with a sensing time of 20 ms for a total of 50 gate lines, the average value of the threshold voltage was measured to be about 322.

Next, an offset value may be calculated by performing total sensing with a sensing time of, for example, 5 ms for all pixels (S330).

At this time, it takes about 43 s to perform total sensing with a sensing time of 5 ms.

After all sensing is performed, an average value of the measured threshold voltages may be calculated.

9 is a graph showing the result of total sensing as an example, and shows the result of measuring the threshold voltage by performing total sensing with a sensing time of 5 ms for 2160 gate lines.

In this case, in FIG. 9, the horizontal axis represents the number of the gate line, and the vertical axis represents the threshold voltage value.

Referring to FIG. 9, as a result of performing total sensing with a sensing time of 5 ms for all 2160 gate lines, the average value of the threshold voltage was measured to be about 117. Accordingly, the difference from the average value of 322 of sampling sensing, that is, the offset value, was 205 is calculated as

Next, the threshold voltage value is corrected by applying (and adding to) the calculated offset value to the total sensing result of 5 ms, that is, to the threshold voltage measured by performing all sensing, which may take about 1 s (S340).

10 is a graph showing a result of applying an offset according to sampling sensing to a result of total sensing as an example.

In this case, in FIG. 10, the horizontal axis represents the number of the gate line, and the vertical axis represents the threshold voltage value.

Referring to FIG. 10, it can be seen that a 20 ms compensation screen can be implemented with a 5 ms sensing time by correcting the threshold voltage value by applying the calculated offset value to the threshold voltage measured by performing total sensing with a 5 ms sensing time.

This compensation method is possible because the correlation coefficient is similar even when the sensing time is changed from the existing 30 ms to 20 ms, 10 ms, and 5 ms.

11A to 11D are graphs showing correlation coefficients according to changes in sensing time as examples.

In this case, FIGS. 11A, 11B, 11C, and 11D show correlation coefficients of sensing times of 20 ms, 10 ms, 5 ms, and 1 ms with respect to sensing times of 30 ms, respectively.

Referring to FIGS. 11A to 11D , it can be seen that even when the sensing time is changed from the existing 30 ms to 20 ms, 10 ms, and 5 ms, the correlation coefficients are similar at about 0.991, 0.991, and 0.985, respectively. That is, it can be seen that the sensing time of 20 ms and the threshold voltage measurement value of 5 ms have a high correlation.

However, in the case of a sensing time of 1 ms, it is impossible to use because sensing is not performed.

Next, the corrected threshold voltage value is input to an external computer through communication, and it may take about 52 s (S350).

Thereafter, the corrected threshold voltage value may be recalled/processed and input to a memory such as a DDR SDRAM (S360 and S370).

At this time, it takes about 5 s to calculate the threshold voltage value, and about 28 s to input the memory, so that the entire external compensation process takes about 131 s. This means that the tak time of the compensation process can be reduced by up to 50% compared to the existing 260s.

For reference, 'DDR' is an abbreviation of 'Double Data Rate', and 'DDR SDRAM' transmits data twice with one clock signal, which is the standard when a command is entered or data is output. It refers to next-generation high-speed DRAM with increased transmission speed. Compared to the existing SDRAM, which transmits or receives data once per signal, the data transmission speed is more than twice as fast.

Next, after external compensation is performed by correcting the threshold voltage, a lighting test may be performed.

At this time, the lighting inspection may be performed in an auto probe process for quality inspection after the cell process, or may be performed in a compensation process after attaching a driver IC during a module process.

Although many details are specifically described in the above description, this should be interpreted as an example of a preferred embodiment rather than limiting the scope of the invention. Therefore, the invention should not be defined according to the described examples, but should be defined according to the scope of the claims and the scope of the claims.

200: external compensation system 210: display panel
220: Control PCB 230: POT
240: Interface PCB 250: PC

Claims (10)

A compensation method for an organic light emitting display device including a display panel in which a plurality of data lines and sensing lines and a plurality of gate lines intersect and pixels are disposed in each intersection area, the method comprising:
performing sampling sensing on some of the gate lines;
performing total sensing on all pixels with a shorter sensing time than the sampling sensing;
Calculating an offset value using an average value of threshold voltages measured through the sampling sensing and the total sensing; and
Comprising the step of correcting the calculated offset value by adding it to the threshold voltage measured by performing the total sensing;
The plurality of gate lines may include a plurality of first gate lines to which scan control signals are sequentially supplied; and a plurality of second gate lines to which sensing control signals are sequentially supplied;
Each pixel of the pixels is connected to one of the data lines, to one of the sensing lines, to one of the first gate lines, and to one of the second gate lines;
Each pixel of the pixels is connected to a data line in response to the scan control signal input through the first gate line, and connected to a sensing line in response to the sensing control signal input through the second gate line. Compensation method of electroluminescence display device. The method of claim 1 , wherein the sampling and sensing are performed with a sensing time of 20 ms. The compensation method of claim 1 , wherein the sampling and sensing are performed by selecting some gate lines in a partial region among all gate lines. The method of claim 1 , wherein the total sensing is performed with a sensing time of 5 ms. The method of claim 1 , further comprising calculating an average value of the measured threshold voltages after performing the sampling and sensing. 6. The method of claim 5, further comprising calculating an average value of the measured threshold voltages after performing the total sensing. 7. The method of claim 6, wherein calculating the offset value comprises:
A compensation method for an organic light emitting display device that calculates a value obtained by subtracting the average value of the threshold voltages measured through the total sensing from the average value of the threshold voltages measured through the sampling sensing. The method of claim 1 , further comprising the step of performing a lighting test after performing external compensation by correcting the threshold voltage. The method of claim 8 , wherein the lighting inspection is performed in an auto probe process for inspecting image quality after a cell process. 9. The method of claim 8, wherein the lighting inspection is performed in a compensation process after attaching a driver IC in a module process.

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