阅读说明：本技术 发光显示装置及感测其劣化的方法 (Light emitting display device and method of sensing deterioration thereof ) 是由 金河中 于 2021-06-08 设计创作，主要内容包括：公开了一种发光显示装置及感测其劣化的方法。所述发光显示装置包括：显示面板,所述显示面板包括高电位电源电压线、低电位电源电压线和多个像素,每个像素包括驱动晶体管和有机发光二极管；时序控制器,在感测模式中配置为：根据通过对于每个像素累积图像数据而获得的累积图像数据的大小产生N个感测图像,并且将N个感测图像中的至少一个感测图像显示在所述显示面板上并获得有机发光二极管的劣化量,其中N是自然数；和劣化感测单元,配置为：通过在显示面板上显示至少一个感测图像的状态下按每个面板或按面板中的每个区域感测电学物理量来估测有机发光二极管的劣化量,并且将有机发光二极管的劣化量提供至时序控制器。(A light emitting display device and a method of sensing degradation thereof are disclosed. The light emitting display device includes: a display panel including a high potential power voltage line, a low potential power voltage line, and a plurality of pixels, each pixel including a driving transistor and an organic light emitting diode; a timing controller configured to, in a sensing mode: generating N sensing images according to a size of accumulated image data obtained by accumulating image data for each pixel, and displaying at least one of the N sensing images on the display panel and obtaining a deterioration amount of the organic light emitting diode, where N is a natural number; and a degradation sensing unit configured to: the method includes estimating a degradation amount of the organic light emitting diode by sensing an electrical physical quantity per panel or per region in the panel in a state where at least one sensed image is displayed on the display panel, and providing the degradation amount of the organic light emitting diode to the timing controller.)

1. A light emitting display device comprising:

a display panel including a high potential power voltage line, a low potential power voltage line, and a plurality of pixels, each pixel including a driving transistor and an organic light emitting diode;

a timing controller configured in a sensing mode to: generating N sensing images according to a size of accumulated image data obtained by accumulating image data for each pixel, where N is a natural number, and displaying at least one of the N sensing images on the display panel and obtaining a deterioration amount of an organic light emitting diode; and

a degradation sensing unit configured to: estimating a degradation amount of the organic light emitting diode by sensing an electrical physical quantity per panel or per region in a panel in a state where the at least one sensed image is displayed on the display panel, and providing the degradation amount of the organic light emitting diode to the timing controller.

2. The light-emitting display device according to claim 1, wherein the accumulated image data is obtained by accumulating source image data supplied from a system for each pixel.

3. The light-emitting display device according to claim 1, wherein the accumulated image data is obtained by accumulating, for each pixel, compensated image data obtained by compensating a source image data based on a threshold voltage of a driving transistor of each pixel or an electron mobility of the driving transistor of each pixel.

4. The light emitting display device according to claim 1, wherein the timing controller comprises:

an accumulation calculator configured to receive source image data from a host system and cumulatively calculate the source image data for each pixel;

an arranging unit configured to compare the accumulated image data calculated by the accumulation calculator and arrange pixels in order of a size of the accumulated image data; and

a generation unit configured to: generating a first sensing image by selecting pixels from first to nth based on a size of the accumulated image data among the pixels arranged by the arrangement unit; generating a second sensing image by selecting pixels from (n +1) th to 2n th based on a size of the accumulated image data among the pixels arranged by the arrangement unit; and generating an nth sensed image by selecting pixels from ((N-1) N +1) th to nth based on a size of the accumulated image data among the pixels arranged by the arrangement unit in the same manner, where N is a natural number.

5. The light emitting display device according to claim 1, wherein the timing controller comprises:

an accumulation calculator configured to receive compensation image data obtained by compensating a source image data based on a threshold voltage of a driving transistor or an electron mobility of the driving transistor and accumulatively calculate the compensation image data for each pixel;

an arranging unit configured to compare the accumulated compensated image data for each pixel calculated by the accumulation calculator and to arrange the pixels in order of a size of the accumulated compensated image data; and

a generation unit configured to: generating a first sensing image by selecting pixels from first to nth based on a size of the accumulated compensated image data among the pixels arranged by the arrangement unit; generating a second sensing image by selecting pixels from (n +1) th to 2n th based on a size of the accumulated compensated image data among the pixels arranged by the arrangement unit; and generating an nth sensed image by selecting pixels from ((N-1) N +1) th to Nn th based on a size of the accumulated compensated image data among the pixels arranged by the arrangement unit in the same manner, where N is a natural number.

6. The light-emitting display device according to any one of claims 4 and 5, wherein, to generate each sensed image, the generation unit sets a high gradation value as a data value in a selected pixel and sets a black value as a data value in an unselected pixel.

7. The light-emitting display device according to any one of claims 4 and 5, wherein the timing controller further comprises:

a storage unit configured to store the N sensed images generated by the generation unit; and

an output unit configured to read at least one of the N sensed images stored in the storage unit and supply the read sensed image to a data driver according to control of the timing controller.

8. The light-emitting display device according to any one of claims 4 and 5, wherein the arranging unit arranges the accumulated image data or the accumulated compensated image data of each pixel in order from largest to smallest based on a size of the accumulated image data or the accumulated compensated image data.

9. The light-emitting display device according to claim 1, wherein the degradation sensing unit comprises:

a first switching device configured to supply a high potential power supply voltage to a high potential power supply voltage line of the display panel according to a first control signal in a display mode;

a voltage/current converter configured to convert the high potential power supply voltage into a current;

a second switching device configured to supply the current converted by the voltage/current converter to the high-potential power supply voltage line according to a second control signal in the sensing mode; and

an analog-to-digital converter configured to convert a voltage of a high-potential power supply voltage line of the display panel into a digital signal and supply the converted digital signal to the timing controller in the sensing mode.

10. The light emitting display device of claim 1, wherein the timing controller, in the sensing mode, is further configured to: the threshold voltage of the driving transistor of each pixel or the electron mobility of the driving transistor of each pixel is sensed by a reference voltage line connected to each pixel, respectively.

11. A light emitting display device according to claim 1, wherein the degradation sensing unit is further configured to estimate the degradation amount of the organic light emitting diode by sensing the electrical physical quantity and converting the sensed data into a digital signal.

12. A method of sensing degradation of a light emitting display device, the method comprising:

accumulating the image data for each pixel;

generating N sensed images by arranging pixels in order of the size of the accumulated image data and selecting a predetermined number of pixels as one image, where N is a natural number;

displaying at least one of the N sensed images on a display panel; and

estimating a degradation amount of the organic light emitting diode by sensing the electrical physical quantity per panel or per region in the panel in a state where the at least one sensed image is displayed on the display panel.

13. The method of claim 12, wherein generating the N sensed images comprises:

generating a first sensing image by selecting pixels from first to nth based on a size of the accumulated image data among the arranged pixels, where n is a natural number;

generating a second sensing image by selecting pixels from (n +1) th to 2n th based on a size of the accumulated image data among the arranged pixels;

generating an nth sensing image by selecting pixels from ((N-1) N +1) th to Nn th based on a size of the accumulated image data among the arranged pixels in the same manner;

setting the high gray value to a data value in the selected pixel; and

the black value is set to the data value in the unselected pixel.

14. The method of claim 12, wherein accumulating image data for each pixel comprises: source image data is received from a host system and cumulatively computed for each pixel.

15. The method of claim 12, wherein accumulating image data for each pixel comprises: compensation image data obtained by compensating source image data received from a host system based on a threshold voltage of a driving transistor of each pixel or an electron mobility of the driving transistor of each pixel is cumulatively calculated for each pixel.

16. The method of claim 12, wherein estimating the amount of degradation of the organic light emitting diode comprises:

displaying the at least one sensed image by supplying a high potential power supply voltage to a high potential power supply voltage line of the display panel; and

supplying a current to a high-potential power supply voltage line of the display panel and sensing a voltage of the high-potential power supply voltage line of the display panel.

17. The method of claim 12, further comprising:

sequentially displaying the N sensed images on the display panel; and

the degradation amount of the N organic light emitting diodes is estimated by sensing the electrical physical quantity per panel or per region in the panel in a state where each sensed image is displayed.

18. The method of claim 12, wherein arranging the pixels in order of size of the accumulated image data comprises: the accumulated image data of each pixel is arranged in order from the largest to the smallest based on the size of the accumulated image data.

19. The method of claim 12, wherein estimating the amount of degradation of the organic light emitting diode comprises: estimating the degradation amount of the organic light emitting diode by sensing the electrical physical quantity per panel or per region in a panel in a state where the at least one sensed image is displayed on the display panel and converting the sensed data into a digital signal.

Technical Field

The present invention relates to a light emitting display device capable of performing degradation compensation by sensing a degradation rate (degradation rate) of each light emitting display panel or region due to process deviation and a method of sensing degradation of the light emitting display device.

Background

In the information society, a large number of techniques have been developed in the field of display devices for displaying visual information as images. Among display apparatuses, an organic light emitting display apparatus displays an image using a self light emitting device such as an organic light emitting diode.

The organic light emitting display device has a fast response speed due to the use of a self-light emitting device that emits light in a light emitting layer by recombination of electrons and holes, has high luminance and low driving voltage at the same time and can be ultra-thin, and can be realized in a free shape, and thus attracts attention as a next generation display.

The organic light emitting display device includes: a display panel including data lines, scan lines, and a plurality of sub-pixels formed at intersections between the data lines and the scan lines; a gate driver for supplying a scan signal to the scan lines; and a data driver for supplying a data voltage to the data lines.

Each sub-pixel includes an organic light emitting diode and a pixel circuit for independently driving the organic light emitting diode. The pixel circuit includes: a driving transistor for adjusting an amount of current supplied to the organic light emitting diode according to a voltage of the gate electrode; and a scan transistor for supplying a data voltage of the data line to a gate electrode of the driving transistor in response to a scan signal of the scan line.

The threshold voltage of the driving transistor is different for each pixel due to process variation during the manufacture of the organic light emitting display device or degradation of the driving transistor due to long-term driving. That is, when the same data voltage is applied to the pixels, the current supplied to each organic light emitting diode needs to be constant, but even if the same data voltage is applied to the pixels, the current supplied to the organic light emitting diode may vary for each pixel due to the difference in threshold voltage of the driving transistor between the pixels. The organic light emitting diode is also deteriorated due to long-term driving, and in this case, the luminance of the organic light emitting diode is also changed for each pixel. Thus, even if the same data voltage is applied to the pixels, the luminance of light emitted from the organic light emitting diode varies for each pixel. To overcome this problem, a compensation method for compensating for the threshold voltage of the driving transistor and the degradation of the organic light emitting diode is provided.

An external compensation method is used to compensate for the threshold voltage of the driving transistor and the degradation of the organic light emitting diode. The external compensation method is a method of applying a preset data voltage to a pixel, sensing a source voltage of a driving transistor through a preset sensing line according to the preset data voltage, converting the sensed voltage into sensing data, which is digital data, using an analog-to-digital converter, and compensating digital video data to be supplied to the pixel according to the sensing data.

This conventional compensation method is to compensate each organic light emitting diode on the assumption that the same degradation occurs in each display panel or within one display panel.

However, since the degradation rate is different for each display panel or for each region within one display panel due to process variations of the organic light emitting diode, there is a problem in that a compensation error occurs and image sticking (image sticking) occurs when a degradation amount is calculated and compensated based on the same standard degradation model.

Disclosure of Invention

Accordingly, it is an object of the present invention to provide a light emitting display device and a method of sensing degradation thereof, which estimates a degradation level by sensing an electrical physical quantity per display panel or per region in a single panel and compensates the values per panel or per region in a single panel, thereby overcoming a compensation error due to a process deviation.

In one aspect, the present invention provides a light emitting display device including: a display panel, a timing controller, and a degradation sensing unit. The display panel includes a high potential power voltage line, a low potential power voltage line, and a plurality of pixels, each including a driving transistor and an organic light emitting diode. The timing controller may be configured in a sensing mode to: generating N (N is a natural number) sensing images according to a size of accumulated image data obtained by accumulating image data for each pixel, displaying at least one of the N sensing images on the display panel and obtaining a degradation amount of an organic light emitting diode. The degradation sensing unit may be configured to: estimating a degradation amount of an organic light emitting diode by sensing an electrical physical quantity per panel or per region in a panel in a state where the at least one sensed image is displayed on the display panel, and providing the degradation amount of the organic light emitting diode to the timing controller.

The image data may be source image data provided from a host system or compensated image data obtained by compensating the source image data based on a threshold voltage of a driving transistor of each pixel or electron mobility of the driving transistor of each pixel.

The timing controller may include: an accumulation calculator configured to receive the source image data or the compensation image data from the host system and accumulatively calculate image data for each pixel; an arranging unit configured to compare the accumulated image data calculated by the accumulation calculator and arrange pixels in order of a size of the accumulated image data; and a generating unit configured to: generating a first sensing image by selecting pixels from first to nth (n is a natural number) based on a size of the accumulated image data among the pixels arranged by the arrangement unit; generating a second sensing image by selecting pixels from (n +1) th to 2n th based on a size of the accumulated image data among the pixels arranged by the arrangement unit; and generating an nth sensed image by selecting pixels from ((N-1) N +1) th to Nn th pixels based on a size of the accumulated image data among the pixels arranged by the arrangement unit in the same manner.

To generate each sensed image, the generation unit may set a high gray value as a data value in a selected pixel and may set a black value as a data value in an unselected pixel.

The timing controller may further include: a storage unit configured to store the N sensed images generated by the generation unit; and an output unit configured to read at least one of the N sensing images stored in the storage unit and supply the read sensing image to a data driver according to control of the timing controller.

The degradation sensing unit may include: a first switching device configured to supply a high potential power supply voltage to a high potential power supply voltage line of the display panel according to a first control signal in a display mode; a voltage/current converter configured to convert the high potential power supply voltage into a current; a second switching device configured to supply the current converted by the voltage/current converter to the high-potential power supply voltage line according to a second control signal in the sensing mode; and an analog-to-digital converter configured to convert a voltage of a high-potential power supply voltage line of the display panel into a digital signal and supply the converted digital signal to the timing controller in the sensing mode.

In another aspect, the present invention provides a method of sensing degradation of a light emitting display device, comprising: accumulating the image data for each pixel; generating N (N is a natural number) sensed images by arranging pixels in order of the size of the accumulated image data and selecting a predetermined number of pixels as one image; displaying at least one of the N sensed images on a display panel; and estimating a degradation amount of the organic light emitting diode by sensing the electrical physical quantity per panel or per region in the panel in a state where the at least one sensed image is displayed on the display panel.

Generating the N sensed images may include: generating a first sensing image by selecting pixels from first to nth (n is a natural number) based on a size of the accumulated image data among the arranged pixels; generating a second sensing image by selecting pixels from (n +1) th to 2n th based on a size of the accumulated image data among the arranged pixels; generating an nth sensing image by selecting pixels from ((N-1) N +1) th to Nn th based on a size of the accumulated image data among the arranged pixels in the same manner; setting the high gray value to a data value in the selected pixel; and setting the black value to the data value in the unselected pixel.

Estimating the degradation amount of the organic light emitting diode includes: displaying a sensing image by supplying a high potential power voltage to a high potential power voltage line of the display panel; and supplying a current to a high-potential power voltage line of the display panel and sensing a voltage of the high-potential power voltage line of the display panel.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

In the drawings:

fig. 1 is a schematic block diagram showing a configuration of a light emitting display device according to an embodiment of the present invention;

fig. 2 is a plan view of an organic light emitting display device according to an embodiment of the present invention;

fig. 3 is a circuit diagram showing a pixel, a source driver IC, a reference voltage generating unit, and an analog-to-digital converter according to an embodiment of the present invention;

fig. 4 is a waveform diagram illustrating a scan signal, a sensing signal, a first switch control signal, a second switch control signal, a gate voltage, and a source voltage supplied to a pixel in a first sensing mode according to the present invention;

fig. 5 is a circuit diagram of fig. 3 illustrating a driving state in the first period of fig. 4;

fig. 6 is a circuit diagram of fig. 3 illustrating a driving state in the second period of fig. 4;

fig. 7 is a graph showing a luminance change of each organic light emitting diode according to time for explaining a second sensing mode in the organic light emitting display device according to the present invention;

fig. 8 is a diagram illustrating a detailed configuration of a timing controller (T-con) for obtaining a degradation degree of an organic light emitting diode OLED according to the present invention;

fig. 9 is a diagram for explaining a method of selecting a sensed image according to the present invention;

fig. 10 is a view for explaining a method of generating sensed image data according to the present invention;

fig. 11 is a circuit diagram of a degradation sensing unit of a light emitting display device according to the present invention;

fig. 12 is a graph showing a display mode and a second sensing mode in the light emitting display device according to the present invention, a first control signal and a second control signal applied to the degradation sensing unit, a driving region of the driving transistor, and a driving state of the high-potential power supply voltage line of the display panel;

fig. 13 is a diagram of a distribution of degradation sensing values using a degradation sensing method according to a comparative example;

fig. 14 is a diagram of a distribution of degradation sensing values using the degradation sensing method according to the present invention.

Detailed Description

In order to obtain a sufficient understanding of the present invention, its advantages, and the objects obtained by its implementation, reference will be made to the accompanying drawings which illustrate exemplary embodiments of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly and completely providing the invention and fully conveying the concept of the invention to those skilled in the art.

Shapes, sizes, ratios, angles, numbers, etc., disclosed in the drawings for describing the embodiments of the present invention are merely exemplary, and the present invention is not limited thereto. Like reference numerals refer to like elements throughout. In the following description of the present invention, when it is determined that detailed description of known related art may unnecessarily obscure the subject matter of the present invention, detailed description thereof will be omitted.

As used herein, the terms "comprising," "having," "including," and the like are intended to mean that additional components may be added, unless the term "only" is used.

Elements in various embodiments of the present invention should be construed to include error margins even if not explicitly stated.

When an element is referred to as being "on," "above," "below," and "beside" an element in describing positional relationships, another element may be disposed between the elements unless the terms "directly next" or "directly" are explicitly used.

When an element is referred to as being "after," "then," and "before" an element in describing a temporal relationship, the events may not be sequential unless the terms "immediately" or "directly" are explicitly used.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and a second element could be termed a first element, without departing from the teachings of the present invention.

The terms "x-axis direction", "y-axis direction" and "z-axis direction" should not be construed merely to mean that the relationship therebetween is a strictly perpendicular geometric relationship, but rather that these terms have a broader orientation within the scope of the construction according to the invention being functionally operable.

The term "at least one" should be understood to include all combinations of one or more of the associated items. For example, the meaning of "at least one of a first item, a second item, and a third item" can refer to all combinations of two or more items selected from the first item, the second item, and the third item, as well as each of the first item, the second item, and the third item.

With regard to the following description of the present invention, the features of the exemplary embodiments of the present invention may be combined in part or in whole. As will be clearly understood by those skilled in the art, various interactions and operations are technically possible. The exemplary embodiments may be implemented independently or in combination.

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

Fig. 1 is a block diagram illustrating a configuration of a light emitting display device according to an embodiment of the present invention. Fig. 2 is a plan view of an organic light emitting display device according to an embodiment of the present invention. Fig. 3 is a circuit diagram showing a pixel, a source driver IC, a reference voltage generating unit, and an analog-to-digital converter according to an embodiment of the present invention.

As shown in fig. 1 and 2, the organic light emitting display device according to an embodiment of the present invention may include a display panel 10, a data driver 20, a gate driver 40, a source printed circuit board (S-PCB)50, a timing controller (T-con)60, a degradation sensing unit 65, an external compensation circuit (or digital data compensation unit) 70, a reference voltage generator (or voltage supply unit) 80, and a Control Printed Circuit Board (CPCB) 90.

The display panel 10 may include a display area DA and a non-display area NDA. The display area DA may be an area where the pixels P are formed to display an image. The non-display area NDA may be an area disposed around the display area DA. The display panel 10 may include data lines D1 to Dm (m is a positive integer equal to or greater than 2), reference voltage lines R1 to Rp (p is a positive integer equal to or greater than 2), scan lines S1 to Sn (n is a positive integer equal to or greater than 2), and sensing signal lines SE1 to SEn. The data lines D1 to Dm and the reference voltage lines R1 to Rp may cross the scan lines S1 to Sn and the sensing signal lines SE1 to SEn, respectively. The data lines D1 to Dm and the reference voltage lines R1 to Rp may be arranged in parallel with each other. The scan lines S1 to Sn and the sensing signal lines SE1 to SEn may be arranged in parallel with each other.

Each pixel P may be connected to any one of the data lines D1 to Dm, any one of the reference voltage lines R1 to Rp, any one of the scan lines S1 to Sn, and any one of the sensing signal lines SE1 to SEn. The pixels P may be disposed on the lower substrate 11 of the display panel 10. Each pixel P may include an Organic Light Emitting Diode (OLED) and a plurality of transistors for supplying current to the Organic Light Emitting Diode (OLED).

The data driver 20 may include a plurality of source driver ics (sdics) 21. Each of the plurality of source driver ICs 21 may receive the compensated digital video data CDATA, the sensed image data SDATA, and the data timing control signal DCS from the timing controller (T-con) 60. The plurality of source driver ics (sdics) 21 may be connected to the data lines D1 to Dm and may supply data voltages to the data lines D1 to Dm. A plurality of source driver ics (sdics) 21 may be respectively mounted on the flexible films 22.

Each flexible film 22 may be a tape carrier package or a chip on film. The flexible membrane 22 may bend or flex. Each flexible membrane 22 may be attached to the lower substrate 11 and a source printed circuit board (S-PCB) 50. Each of the flexible films 22 may be attached to the lower substrate 11 using a Tape Automated Bonding (TAB) method using an anisotropic conductive film, and thus the plurality of source driver ics (sdic)21 may be connected to the data lines D1 to Dm. The source printed circuit board (S-PCB)50 may be connected to a Control Printed Circuit Board (CPCB)90 through a flexible cable 91.

The data driver 20 may be connected to the reference voltage lines R1 to Rp and may sense a threshold voltage of a driving transistor or an electron mobility of the driving transistor of each pixel P. The data driver 20 may generate the sensing data SD using the sensed voltage and may provide the sensing data SD to the external compensation circuit 70.

The gate driver 40 may include a scan signal output unit 41 and a sensing signal output unit 42.

The scan signal output unit 41 may be connected to the scan lines S1 through Sn. The scan signal output unit 41 may provide scan signals to the scan lines S1 through Sn according to a scan timing control signal SCS input from the timing controller 60.

The sensing signal output unit 42 may be connected to the sensing signal lines SE1 to SEn. The sensing signal output unit 42 may supply sensing signals to the sensing signal lines SE1 to SEn according to a sensing timing control signal SENS input from the timing controller 60.

The scan signal output unit 41 and the sensing signal output unit 42 may include a plurality of transistors and may be directly formed on the non-display area NDA of the display panel 10 using a gate driver in panel (GIP) method. Alternatively, the scan signal output unit 41 and the sensing signal output unit 42 may be formed in the form of a driving chip and may be mounted on a flexible film connected to the display panel 10.

The timing controller 60 may receive source image data and timing signals from a host system. The timing signals may include a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a dot clock. The host system may be any of a computer system, a TV system, a set-top box, and a portable terminal such as a tablet or cellular phone.

The timing controller 60 may perform various image processes for correcting image quality and compensating for degradation of the light emitting device by accumulating the source image data.

The timing controller 60 may perform various image processes for correcting image quality and compensating for degradation of the light emitting device by accumulating the compensated image data.

In order to estimate the degree of degradation by the entire area of the display panel 10 or by each area, the timing controller 60 may accumulate data of each pixel of the display panel based on source image data or compensation image data, may arrange the accumulated data in order of the size of the accumulated data of each pixel, may generate N sensed image data (N is a natural number) composed of pixel blocks having a predetermined number N (N is a natural number) from the largest accumulated data or may select a predetermined number N (N is a natural number) of pixels as one image to generate N sensed images, and may store the N sensed image data in a memory (not shown, refer to the storage unit 74 of fig. 8).

In order to obtain the degradation degree by the entire area of the display panel 10 or by each area, the timing controller 60 may supply the N sensed image data stored in the memory to the data driver 20, may display each of the N sensed image data on the display panel 10, and may obtain the degradation degree each time each of the N sensed image data is displayed. A method of obtaining the degree of degradation each time each of the N pieces of sensed image data is displayed will be described in detail below.

The timing controller 60 may generate timing control signals for controlling operation timings of the data driver 20, the scan signal output unit 41, and the sensing signal output unit 42. The timing control signal may include: a data timing control signal DCS for controlling the operation timing of the data driver 20, a scan timing control signal SCS for controlling the operation timing of the scan signal output unit 41, and a sense timing control signal SENS for controlling the operation timing of the sense signal output unit 42.

The timing controller 60 may output the compensated digital video data CDATA from the external compensation circuit 70, the sensed image data generated from the accumulated data, and the data timing control signal DCS to the data driver 20. The timing controller 60 may output the scan timing control signal SCS to the scan signal output unit 41. The timing controller 60 may output the sensing timing control signal SENS to the sensing signal output unit 42. The timing controller 60 may output switch control signals SCS1 and SCS2 for controlling the switches SW1 and SW2 of the data driver 20.

The timing controller 60 may control the organic light emitting display device according to the present invention in any one of a display mode, a first sensing mode for sensing a threshold voltage of the driving transistor or an electron mobility of the driving transistor, and a second sensing mode for sensing degradation of the Organic Light Emitting Diode (OLED).

The display mode may be a mode in which the pixel P emits light by applying a data voltage based on the compensated image data CDATA to the pixel P.

In the first sensing mode, the threshold voltage of the driving transistor or the electron mobility of the driving transistor of each pixel P may be sensed through the reference voltage lines R1 to Rp connected to the pixels P, respectively.

In the second sensing mode, a data voltage based on N pieces of sensed image data SDATA generated from the accumulated data may be supplied and displayed on the pixels P through the data driver 20, and a degradation degree, i.e., a degradation level, of the OLED may be estimated per panel or per area in the panel by sensing an electrical physical quantity (ELVDD current/voltage) and converting it into a digital signal. Compensation errors due to process variations of the OLED can be overcome by applying the degradation value estimated per panel or per region in the panel. According to the present invention, only the method of estimating (sensing) the degree of deterioration based on N pieces of sensed image data SDATA is described.

The first and second sensing modes may be performed before the organic light emitting display device is powered off, may be performed as soon as the organic light emitting display device is powered on, or may be performed in a predetermined period in a state where the organic light emitting display device is powered on.

The external compensation circuit 70 may generate the compensated image data by compensating the source image data based on the sensing data SD obtained by sensing the threshold voltage of the driving transistor or the electron mobility of the driving transistor. The external compensation circuit 70 may output the compensated digital video data CDATA to the timing controller 60.

The external compensation circuit 70 may include a memory for storing the sensing data SD. The memory of the external compensation circuit 70 may be a non-volatile memory, such as an electrically erasable programmable read-only memory (EEPROM). The external compensation circuit 70 may be installed in the timing controller 60.

The reference voltage generator 80 may generate a reference voltage and may supply the reference voltage to the data driver 20 or a plurality of source driver ics (sdics) 21 included in the data driver 20. The reference voltage generator 80 may generate a low voltage or a high voltage for setting a sensing voltage range in the sensing mode. The reference voltage generator 80 may generate driving voltages required for driving the organic light emitting display device according to the present invention in addition to the reference voltages and may supply the generated voltages to components requiring the voltages.

The degradation sensing unit 65 may estimate (sense) the degradation amount by supplying at least one of the N sensed image data SDATA generated by the timing controller 60 to the data driver 20, and sensing an electrical physical quantity (ELVDD current/voltage) per panel or per region in the panel in a state where a sensed image is displayed on the display panel and converting the sensed data into a digital signal.

The detailed configuration of the degradation sensing unit 65 will be described below.

The timing controller 60, the external compensation circuit 70, and the reference voltage generator 80 may be mounted on a Control Printed Circuit Board (CPCB) 90. The Control Printed Circuit Board (CPCB)90 may be connected to the source printed circuit board (S-PCB)50 through a flexible cable 91.

The organic light emitting display device according to the embodiment of the invention may convert the source image video DATA into the compensated digital video DATA CDATA using the sensing DATA SD obtained by sensing the threshold voltage of the driving transistor or the electron mobility of the driving transistor in the first sensing mode. As a result, according to the present invention, the threshold voltage of the driving transistor of each pixel P and the electron mobility of the driving transistor of each pixel P can be compensated.

Fig. 3 is a circuit diagram showing a pixel P, SDIC 21, a reference voltage generator 80, and an analog-to-digital converter (ADC)140 according to an embodiment of the present invention.

For convenience of description, FIG. 3 shows only pixels connected to the jth (j is a positive integer satisfying 1. ltoreq. j.ltoreq.m) data line Dj, the jth reference voltage line Rj, the kth (k is a positive integer satisfying 1. ltoreq. k.ltoreq.n) scan line Sk, and the kth sense signal line SEk, SDIC 21, reference voltage generator 80, ADC 140, first switch SW1, and second switch SW 2.

Referring to fig. 3, the pixel P may include an organic light emitting diode OLED, a driving transistor DT, a first switching transistor ST1, a second switching transistor ST2, and a storage capacitor Cst.

The organic light emitting diode OLED may emit light according to the current supplied through the driving transistor DT. The organic light emitting diode OLED may include an anode, a hole transport layer, an organic light emitting layer, an electron transport layer, and a cathode. In the organic light emitting diode OLED, when a voltage is applied to the anode and the cathode, holes and electrons may move to the organic light emitting layer through the hole transport layer and the electron transport layer, respectively, and may combine with each other in the organic light emitting layer to emit light. The anode electrode of the organic light emitting diode OLED may be connected to the source electrode of the driving transistor DT, and the cathode electrode may receive a low potential power supply voltage ELVSS lower than the high potential power supply voltage ELVDD.

The driving transistor DT may adjust a current flowing from the line of the high potential power supply voltage ELVDD to the organic light emitting diode OLED according to a difference voltage between the gate electrode and the source electrode thereof. A gate electrode of the driving transistor DT may be connected to a first electrode of the first switching transistor ST1, a source electrode of the driving transistor DT may be connected to an anode electrode of the organic light emitting diode OLED, and a drain electrode of the driving transistor DT may be connected to the high-potential power supply voltage line ELVDD.

The first switching transistor ST1 may be turned on according to a kth scan signal of the kth scan line Sk to connect the jth data line Dj to the gate electrode of the driving transistor DT. A gate electrode of the first switching transistor ST1 may be connected to the kth scan line Sk, a first electrode of the first switching transistor ST1 may be connected to the gate electrode of the driving transistor DT, and a second electrode of the first switching transistor ST1 may be connected to the jth data line Dj.

The second switching transistor ST2 may be turned on according to a sensing signal of the kth sensing signal line SEk to connect the jth reference voltage line Rj to the source electrode of the driving transistor DT. A gate electrode of the second switching transistor ST2 may be connected to the kth sensing signal line SEk, a first electrode of the second switching transistor ST2 may be connected to the jth reference voltage line Rj, and a second electrode of the second switching transistor ST2 may be connected to the source electrode of the driving transistor DT.

The first electrode of each of the first and second switching transistors ST1 and ST2 may be a source electrode, and the second electrode of each of the first and second switching transistors ST1 and ST2 may be a drain electrode, but it should be noted that the present invention is not limited thereto. That is, the first electrode of each of the first and second switching transistors ST1 and ST2 may be a drain electrode, and the second electrode of each of the first and second switching transistors ST1 and ST2 may be a source electrode.

The storage capacitor Cst may be formed between the gate electrode and the source electrode of the driving transistor DT. The storage capacitor Cst may store a difference voltage between the gate voltage and the source voltage of the driving transistor DT.

Each of the driving transistor DT, the first switching transistor ST1, and the second switching transistor ST2 may be formed as a thin film transistor. Fig. 3 illustrates that the driving transistor DT, the first switching transistor ST1 and the second switching transistor ST2 take the form of N-type Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), but it should be noted that the present invention is not limited thereto. Each of the driving transistor DT, the first switching transistor ST1, and the second switching transistor ST2 may be a P-type MOSFET.

The SDIC 21 may convert the compensated image data (or the compensated digital video data) CDATA into a data voltage according to the data timing control signal DCS in the display mode and may supply the data voltage to the data line Dj. The display mode may be a mode in which the pixel P emits light to display an image. The data voltage may be a voltage for emitting light having a predetermined brightness in the organic light emitting diode OLED of the pixel P.

The SDIC 21 may convert the sensed image data SDATA into a sensed data voltage according to the data timing control signal DCS in the sensing mode and may supply the sensed data voltage to the data line Dj.

The first sensing mode may be any one of a threshold voltage compensation mode for sensing a source voltage of the driving transistor DT so as to compensate for a threshold voltage of the driving transistor of each pixel P and a mobility compensation mode; the mobility compensation mode is for sensing the source voltage of the driving transistor DT in order to compensate for the electron mobility of the driving transistor of each pixel P.

The ADC 140 may convert the voltage sensed from the reference voltage line Rj into sensing data SD, i.e., digital data, in the first sensing mode, and may output the sensing data SD to the external compensation circuit 70.

The first switch SW1 may be connected between the reference voltage line Rj and the reference voltage generator 80 and may switch the connection between the reference voltage line Rj and the reference voltage generator 80. The first switch SW1 may be turned on and off according to a first switch control signal SCS1 output from the timing controller 60. When the first switch SW1 is turned on according to the first switch control signal SCS1, the reference voltage line Rj may be connected to the reference voltage generator 80, and thus the reference low voltage generated by the reference voltage generator 80 may be supplied to the reference voltage line Rj.

The second switch SW2 may be connected between the reference voltage line Rj and the ADC 140, and may switch the connection between the reference voltage line Rj and the ADC 140. The second switch SW2 may be turned on and off according to a second switch control signal SCS2 output from the timing controller 60. When the second switch SW2 is turned on according to the second switch control signal SCS2, the reference voltage lines Rj may be connected to the ADC 140, and thus the threshold voltage of the driving transistor of each pixel P may be sensed through each of the reference voltage lines Rj.

Fig. 4 is a waveform diagram illustrating the scan signal SCANk, the sensing signal SENSk, the first switching control signal SCS1, the second switching control signal SCS2, the gate voltage Vg, and the source voltage Vs supplied to the pixel P in the first sensing mode.

In the first sensing mode, one frame period may include a first period t1 and a second period t 2. The first period t1 may be the time taken to initialize the source electrode of the driving transistor DT to the reference voltage VREF. The second period t2 may be a time taken to apply the sensing data voltage SVdata to the gate electrode of the driving transistor DT and sense the source voltage of the driving transistor DT.

The kth scan signal SCANk of the kth scan line Sk may be supplied as the gate-on voltage Von during the second period t 2. Although an example in which the kth scan signal SCANk of the kth scan line Sk is supplied as the gate-off voltage Voff during the first period t1 is described, the kth scan signal SCANk may also be supplied as the gate-on voltage Von. The kth sensing signal SENSk of the kth sensing signal line SEk may be supplied as the gate-on voltage Von during the first and second periods t1 and t 2. The first and second switching transistors ST1 and ST2 of the pixel P may be turned on according to the gate-on voltage Vcon and may be turned off according to the gate-off voltage Voff.

The first switch control signal SCS1 may be provided as the first logic level voltage V1 during the first period t1 and may be provided as the second logic level voltage V2 during the second period t 2. The second switch control signal SCS2 may be provided as the second logic level voltage V2 during the first period t1 and may be provided as the first logic level voltage V1 during the second period t 2. Each of the first switch SW1 and the second switch SW2 may be turned on according to a first logic level voltage and may be turned off according to a second logic level voltage.

Fig. 5 is a circuit diagram of fig. 3, which illustrates a driving state in the first period of fig. 4.

The first switching transistor ST1 may be turned off according to a kth scan signal SCANk supplied to a gate-off voltage Voff of the kth scan line Sk during the first period t 1. The second switching transistor ST2 may be turned on according to the kth sensing signal SENSk of the gate-on voltage Von supplied to the kth sensing signal line SEk. The first switch SW1 may be turned on according to the first switch control signal SCS1 of the first logic level voltage V1 during the first period t 1. The second switch SW2 may be turned off according to the second switch control signal SCS2 of the second logic level voltage V2.

Since the first switch SW1 is turned on during the first period t1, the reference voltage VREF may be supplied from the reference voltage generator 80 to the jth reference voltage line Rj. Since the second switching transistor ST2 is turned on during the first period t1, the reference voltage VREF of the jth reference voltage line Rj may be supplied to the source electrode of the driving transistor DT. That is, the source electrode of the driving transistor DT may be initialized to the reference voltage VREF.

Fig. 6 is a circuit diagram of fig. 3, which illustrates a driving state in the second period of fig. 4.

During the second period t2, the first switching transistor ST1 may be turned on according to the kth scan signal SCANk of the gate-on voltage Von supplied to the kth scan line Sk. The second switching transistor ST2 may be turned on according to the kth sensing signal SENSk of the gate-on voltage Von supplied to the kth sensing signal line SEk. During the second period t2, the first switch SW1 may be turned off according to the first switch control signal SCS1 of the second logic level voltage V2. The second switch SW2 may be turned on according to the second switch control signal SCS2 of the first logic level voltage V1.

Since the first switch SW1 is turned off during the second period t2, the reference voltage VREF may not be supplied to the jth reference voltage line Rj. Since the second switch SW2 is turned on during the second period t2, the jth reference voltage line Rj may be connected to the ADC 140. Since the first switching transistor ST1 is turned on during the second period t2, the sensing data voltage SVdata may be provided to the gate electrode of the driving transistor DT. Since the second switching transistor ST2 is turned on during the second period t2, the source electrode of the driving transistor DT may be connected to the ADC 140 through the jth reference voltage line Rj.

Since a voltage difference Vgs (SVdata-VREF) between the gate electrode and the source electrode of the driving transistor DT is greater than the threshold voltage Vth of the driving transistor DT during the second period t2, the driving transistor DT may allow a current to flow.

The source voltage of the driving transistor DT may be raised to "VREF + α". α may vary according to the threshold voltage of the driving transistor DT and the electron mobility of the driving transistor DT. Thus, a voltage obtained by reflecting the threshold voltage of the driving transistor DT or the electron mobility of the driving transistor DT may be sensed in the source electrode of the driving transistor DT during the second period t 2.

Fig. 7 is a graph showing a luminance change of each organic light emitting diode according to time for explaining a second sensing mode in the organic light emitting display device according to the present invention.

In fig. 7, a first organic light emitting diode OLED1 and a second organic light emitting diode OLED2 are illustrated.

As in the case where the organic light emitting diode degrades at a standard degradation rate (i.e., a degradation rate predicted in a standard OLED degradation model), the luminance of the first organic light emitting diode OLED1 decreases over time.

The luminance of the second organic light emitting diode OLED2 decreases over time at a higher rate than the standard degradation rate (i.e., the degradation rate predicted in the standard OLED degradation model).

The second organic light emitting diode OLED2 may be an organic light emitting diode OLED disposed in an area that is easily deteriorated due to its design or a defect of an internal organic light emitting layer, or an area used at high luminance compared to other areas on the display panel 10, or an area that remains in an on state for a relatively long time and is rapidly deteriorated. After the first driving time T1 elapses, the luminance reduction Δ L' of the second organic light emitting diode OLED2 due to the degradation thereof may be greater than the luminance reduction Δ L of the first organic light emitting diode OLED1 due to the degradation thereof, compared to the initial luminance LV _ INI.

In general, the degradation rate of the organic light emitting diode OLED may be different for each display panel 10 due to process variation of the organic light emitting diode OLED, and may also be different for each region in a single display panel 10. Thus, when degradation compensation is performed by estimating the degradation degree of a plurality of display panels 10 or a plurality of regions in a single display panel 10 using a degradation rate model represented by one standard degradation rate, the amount of degradation estimated in the degradation model may be different from the actual degradation degree of the display panel 10. When there is a difference in the degree of deterioration, a deterioration compensation error occurs and image sticking also occurs after the deterioration is compensated for.

Therefore, a method of estimating the degree of degradation of the organic light emitting diode OLED by supplying a data voltage to the data driver 20 according to N pieces of sensing image data SDATA generated from the accumulated data to display a sensing image in the second sensing mode and by sensing the degradation level of the LED as an electrical physical quantity (ELVDD current/voltage) per panel or per region in the panel will be described below.

Fig. 8 is a diagram illustrating a detailed configuration of the timing controller 60 for obtaining the degree of degradation of the organic light emitting diode OLED according to the present invention. Fig. 9 is a diagram for explaining a method of selecting a sensed image according to the present invention. Fig. 10 is a view explaining a method of generating sensed image data according to the present invention.

As shown in fig. 8, the timing controller 60 may include: an accumulation calculator 71, the accumulation calculator 71 receiving source image data from the host system and accumulatively calculating the source image data for each pixel; an arranging unit 72 that arranges the accumulated image data calculated by the accumulation calculator 71 in order of the size of the accumulated image data for each pixel by the arranging unit 72; a generation unit 73, the generation unit 73 generating N (N is a natural number) sensed images (or sensed image data) using a predetermined amount N (N is a natural number) of pixels as one block from the accumulated image data having the largest size based on the arrangement order of the arrangement unit 72; a storage unit 74, the storage unit 74 storing the N sensed image data generated by the generation unit 73; and an output unit 75, the output unit 75 sequentially outputting the N sensed images SDATA stored in the storage unit 74 to the data driver 20.

Here, the operations of the arranging unit 72 and the generating unit 73 will be described in more detail below.

That is, as shown in fig. 9, the arranging unit 72 may arrange the accumulated image data of each pixel in order from the largest to the smallest based on the size of the accumulated image data. The generation unit 73 may select accumulated image data from the first to nth based on the size of the accumulated image data as the first sensing image. The generation unit 73 may select accumulated image data from (n +1) th to 2n th based on the size of the accumulated image data as the second sensed image. In the same manner, the generation unit 73 can select accumulated image data from ((N-1) N +1) th to Nn th based on the size of the accumulated image data as the nth sensed image.

As shown in fig. 10, in each selected sensed image, N sensed image data may be generated by setting a high gray G255 value as a data value in a selected pixel and a black G0 value as a data value in an unselected pixel.

Fig. 11 is a circuit diagram of a degradation sensing unit of a light emitting display device according to the present invention. Fig. 12 is a graph showing a display mode and a second sensing mode in the light emitting display device according to the present invention, a first control signal EL1 and a second control signal EL2 applied to the degradation sensing unit, a driving region of the driving transistor, and a driving state of the high-potential power supply voltage line of the display panel.

The degradation sensing unit 65 may estimate (sense) the degree of degradation by sensing an electrical physical quantity (ELVDD current/voltage) per panel or per region in the panel in a state where a sensed image is displayed on the display panel and converting it into a digital signal.

Accordingly, as shown in fig. 11, the degradation sensing unit 65 may include: a first switching device SW1, the first switching device SW1 supplying a high potential power voltage ELVDD to a high potential power voltage line of the display panel 10 in accordance with the first control signal EL1 in the display mode; a voltage/current converter 62, the voltage/current converter 62 converting the high potential power supply voltage ELVDD into a current i _ ELVDD; a second switching device SW2, the second switching device SW2 supplying a high-potential current i _ ELVDD to the high-potential power voltage line of the display panel 10 according to the second control signal EL2 in the second sensing mode; and an analog-to-digital converter (ADC)61, the ADC 61 converting a voltage of the high-potential power supply voltage line of the display panel 10 into a digital signal in the second sensing mode and supplying it to the timing controller 60. In fig. 11, anodes of the first to k-th organic light emitting diodes OLED1 to OLEDk are connected to the first to k-th driving transistors DT1 to DTk, respectively. As an example, the present invention may sequentially display N sensing images on a display panel, and may estimate the degradation amount of N organic light emitting diodes by sensing an electrical physical quantity per panel or per region in the panel in a state where each sensing image is displayed.

As shown in fig. 12, in the display mode, the first switching device SW1 controlled according to the first control signal EL1 may be turned on, and the second switching device SW2 controlled according to the second control signal EL2 may be turned off.

In the sensing mode, the first switching device SW1 controlled according to the first control signal EL1 may be turned off, and the second switching device SW2 controlled according to the second control signal EL2 may be turned on.

In the display mode, the driving transistor DT of each pixel P may be driven in a saturation region according to the high potential power supply voltage ELVDD applied to the high potential power supply voltage line of the display panel 10 through the first switching device SW 1.

In the sensing mode, the current i _ ELVDD supplied to the high potential power voltage line of the display panel 10 through the second switching device SW2 is sufficiently small, and thus the driving transistor DT of each pixel P of the display panel 10 may be driven in a linear region.

Regarding the driving of the panel ELVDD input terminal, in the display mode, the display panel may perform voltage driving according to the high potential power supply voltage ELVDD; in the sensing mode, the display panel may be current-driven according to the current i _ ELVDD.

In the sensing mode, the display panel 10 displays a sensing image, and thus only selected pixels (driving transistors) selected to generate the sensing image may be turned on, and the remaining unselected pixels may be turned off.

The method of generating N sensed image data and sensing the degradation amount of the OLED (sensing mode) as described above will be described in more detail below.

The accumulation calculator 71 of the timing controller 60 may receive source image data from the host system and may cumulatively calculate the source image data for each pixel.

According to another embodiment, instead of the source image data from the host system, the accumulation calculator 71 may receive compensation image data obtained by the external compensation circuit 70 compensating the source image based on the threshold voltage of the driving transistor or the electron mobility of the driving transistor, and may accumulatively calculate the compensation image data for each pixel.

The arrangement unit 72 may compare the accumulated compensated image data calculated by the accumulation calculator 71 and may arrange the pixels in order of the size of the accumulated compensated image data. That is, as described with reference to fig. 9, the pixels may be arranged from the maximum to the minimum based on the size of the accumulated image data.

The generation unit 73 may select pixels from the first to nth pixels based on the size of the accumulated image data among the pixels arranged by the arrangement unit 72 and may generate the first sensed image. The generation unit 73 may select pixels from (n +1) th to 2n th based on the size of the accumulated image data among the pixels arranged by the arrangement unit 72 and may generate the second sensed image. In the same manner, the generation unit 73 may select pixels from ((N-1) N +1) th to Nn th based on the size of the accumulated image data among the pixels arranged by the arrangement unit 72 and may generate an nth sensed image.

As shown in fig. 10, in each generated sensed image, N sensed image data may be generated by setting a high gray G255 value as a data value in a selected pixel and setting a black G0 value as a data value in an unselected pixel.

The generated N sensed image data may be stored in the storage unit 74.

The timing controller 60 may control the output unit 75 in a second sensing mode for sensing degradation of the organic light emitting diode OLED.

The output unit 75 may read at least one of the N sensed image data stored in the storage unit 74 and may provide it to the data driver 20.

The data driver 20 may display the sensed image data output from the output unit 75 on the display panel 10.

That is, the timing controller 60 may turn on the first switching device SW1 of the degradation sensing unit 65 according to the first control signal EL1 to supply the high potential power voltage ELVDD to the high potential power voltage line of the display panel 10, and the timing controller 60 may control the data driver 20 to supply the sensed image data to the data line of the display panel 10 and display the corresponding sensed image.

Needless to say, as shown in fig. 1, when a sensed image is displayed, the scan signal output unit 41 and the sensing signal output unit 42 of the gate driver 40 may supply scan signals to the scan lines S1 to Sn and may supply sensing signals to the sensing signal lines SE1 to SEn according to the control of the timing controller 60.

As described above, the sensed image may be displayed on the display panel 10, and the timing controller 60 may turn off the first switching device SW1 of the degradation sensing unit 65 according to the first control signal EL1 and may turn on the second switching device SW2 of the degradation sensing unit 65 according to the second control signal EL 2.

Thus, since the current i _ ELVDD is supplied to the high potential power voltage line of the display panel 10 through the second switching device SW2 and is sufficiently small, the driving transistor DT of each pixel P of the display panel 10 may be driven in a linear driving.

In this case, the ADC 61 may convert the voltage of the high-potential power supply voltage line of the display panel 10 into a digital signal and may supply the converted digital signal to the timing controller 60 as the degradation amount of the OLED.

In this process, the output unit 75 may sequentially supply the N sensed image data stored in the storage unit 74 to the data driver 20 and may sense the degradation amount of the OLED for each sensed image while displaying each sensed image.

In the light emitting display device and the method of sensing degradation thereof according to the present invention as described above, the distribution of sensing values between sensing images may be increased and the difference in sensing values between sensing images is higher, and thus a degradation sensing error may be reduced as compared to the comparative example.

Fig. 13 is a diagram of a distribution (frequency of occurrence) of degradation sensing values using the degradation sensing method according to the comparative example. Fig. 14 is a diagram of a distribution (frequency of occurrence) of degradation sensing values using the degradation sensing method according to the present invention.

As shown in fig. 13 and 14, all of the sensing values in the degradation sensing methods according to the comparative example and the present invention may correspond to an average degradation level in the OLED corresponding to the pixels included in the sensed image. However, the degradation sensing methods according to the comparative example and the present invention are different in the degradation uniformity of the OLED corresponding to the pixel included in the sensed image.

When deterioration of sensed images is sensed using the deterioration sensing method according to the comparative example, highly deteriorated pixels and less deteriorated pixels coexist in each sensed image, the sensed value corresponds to an average value of the deterioration levels of these pixels, and cannot be distinguished between the sensed images. That is, as shown in fig. 13, the sensing value distribution range between the sensed images is not large.

In contrast, since each sensed image using the degradation sensing method according to the present invention is an image formed by selecting only pixels corresponding to a constant degradation level in the degradation level distribution of the entire panel, larger sensed values of the sensed image may be sensed sequentially from the maximum among the values of the accumulated data, the sensed value distribution between the sensed images may be increased, and the sensed value difference between the sensed images may be higher, and thus the degradation compensation algorithm using these values may reduce errors compared to the degradation sensing method according to the comparative example.

The light emitting display device and the method of sensing degradation thereof according to the embodiments of the present invention having the aforementioned features may have the following effects.

According to the present invention, since each sensed image is an image formed by selecting only pixels corresponding to a constant degradation level in the degradation level distribution of the entire panel, larger sensing values of the sensed image can be sensed sequentially from the maximum among the values of the accumulated data, the sensing value distribution between the sensed images can be increased, and the sensing value difference between the sensed images can be high, and thus the degradation compensation algorithm using these values can reduce errors.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.