KR20170080889A - Organic Light Emitting Display Device and Method of Driving the same - Google Patents

Abstract

The present invention compensates by reflecting the deterioration characteristics of the device according to the position and performing consistent relative compensation over the entire area of the display panel to increase the degree of freedom of compensation and increase the life of the compensation to alleviate the stress applied to the device, will be.
To this end, according to the present invention, a timing controller for compensating a data signal so that the same luminance is displayed at all positions by varying the weight of a gain when the luminance deviation of each position is predicted using the organic light emitting diode included in the display panel, .

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting display device and a method of driving the same,

The present invention relates to an organic light emitting display and a driving method thereof.

As the information technology is developed, the market of display devices, which is a connection medium between users and information, is getting larger. Accordingly, the use of organic light emitting display (OLED) is increasing.

The organic light emitting display includes a display panel including a plurality of subpixels, a driver for outputting a drive signal for driving the display panel, and a power supply for generating power to be supplied to the display panel and the driver. The driving unit includes a scan driver for supplying a scan signal (or a gate signal) to the display panel, and a data driver for supplying a data signal to the display panel.

When a driving signal, such as a scan signal, a data signal, or the like, is supplied to the subpixels formed on the display panel, the organic light emitting display device displays the image by causing the selected subpixel to emit light. However, in the case of an organic light emitting display, the organic light emitting diode included in the display panel deteriorates with time.

Conventionally, a compensation method has been proposed in which the characteristics of the organic light emitting diode are sensed and compensation is performed corresponding to the sensed value. However, the conventional method increases the stress of the device by supplying more current to the device to compensate the brightness of the organic light emitting diode. As a result, the luminance of the organic light emitting diode temporarily appears to be compensated, but in the long term, the stress of the device is increased, and eventually, only the luminance reduction of the device is accelerated.

The present invention for solving the above-mentioned problems of the background art compensates for the deterioration characteristics of the device according to the position and performs consistent relative compensation over the entire area of the display panel to increase the degree of freedom of compensation, Is to relieve the stress and increase the reliability of compensation.

According to an aspect of the present invention, there is provided an organic light emitting display including a display panel, a driver, and a timing controller. The display panel displays the image. The driving unit drives the display panel. The timing control unit compensates the data signal so that the same luminance is displayed at all positions by varying the weight of the gain when the luminance deviation for each position is predicted using the organic light emitting diode included in the display panel.

The timing controller increases the gain when the current luminance of the organic light emitting diode is lower than the target luminance, and decreases the gain when the current luminance of the organic light emitting diode is higher than the target luminance.

The timing controller can predict and compensate for the luminance deviation of each position based on the data modeled by the temperature and the degree of deterioration of each organic light emitting diode and the image data input from the outside.

The timing control section can compensate the gain based on the average of the average or the histogram for the entire area of the display panel.

The timing controller sets the target luminance to the average luminance of the entire region of the display panel at the current point of time instead of the initial luminance, increases the gain when the current luminance of the organic light emitting diode is lower than the target luminance, and increases the current luminance of the organic light emitting diode to the target luminance The higher the gain, the lower the gain can be.

The timing controller converts the input amount of image data input from the outside, the voltage data obtained by converting the image data into the voltage, and the current data obtained by converting the image data into the current. When the luminance deviation is predicted according to the position, Different weights may be given depending on at least one of the size of the data or the size of the current data.

In another aspect, the present invention provides a method of driving an organic light emitting display. The driving method of the organic light emitting display device includes a step of preparing data modeling the degree of deterioration of the organic light emitting diode according to the temperature and the position of the organic light emitting diode through experiments, the step of generating stress data based on the image data input from outside, Converting the stress data into relative luminance information of the organic light emitting diode, setting a target relative luminance based on the average of the relative luminance of the entire display panel or the mode of the histogram, And providing a gain by the difference between the average of the luminance or the mode of the histogram and the target relative luminance.

In the step of generating the stress data, at least one of an input amount of image data input from outside, a magnitude of voltage data obtained by converting image data into a voltage, a magnitude of current data obtained by converting image data into a current, The stress data can be generated.

 In the step of providing the gain, weights of the gains may be different based on one of the input amount of the image data, the size of the voltage data, and the size of the current data.

In the step of providing the gain, the gain is increased when the current luminance of the organic light emitting diode is lower than the target luminance, and the gain is lowered when the current luminance of the organic light emitting diode is higher than the target luminance.

The present invention compensates for the deterioration characteristics of the device depending on the position and performs consistent relative compensation over the entire area of the display panel, so that the degree of freedom of compensation is high and the compensation life is increased. In addition, the present invention compensates mainly for the afterimage and smudges occurring in the entire area of the display panel, rather than compensating for luminance reduction due to deterioration, thereby relieving stress applied to the device, thereby achieving long lifetime. Further, the present invention analyzes and reflects the deterioration factor of a device in units of subpixels, thereby enhancing the reliability of compensation results. Further, since the present invention does not require a sensing circuit for compensation, the circuit and the layout of the subpixel can be simplified.

1 is a block diagram schematically showing an organic light emitting display device.
Fig. 2 is a schematic view showing the subpixel shown in Fig. 1. Fig.
3 is a flowchart illustrating a compensation scheme proposed in the related art.
4 shows an example of a conventional compensation method.
5 is a graph for explaining a change in luminance according to a conventional compensation method.
6 is a graph for explaining compensation errors due to sensing noise and the like.
7 is a graph for explaining a deterioration model tracking method according to the first embodiment of the present invention.
8 is a graph for explaining the concept of compensation according to the first embodiment of the present invention.
9 is a graph for explaining a parameter setting method according to the first embodiment of the present invention.
10 and 11 are views for explaining the compensation example of the first embodiment of the present invention.
12 is a flowchart for explaining a compensation method according to the first embodiment of the present invention;
13 is a view for explaining the difference between the conventional compensation method and the compensation method of the first embodiment.
FIG. 14 is a view for explaining the comparison between the conventional compensation method and the first embodiment before and after compensation; FIG.
15 is a flowchart for explaining a compensation method according to a second embodiment of the present invention;
16 is a flowchart for explaining a compensation method according to the third embodiment of the present invention.
17 is a flowchart for explaining a compensation method according to a fourth embodiment of the present invention;
18 is a flowchart for explaining a compensation method according to a fifth embodiment of the present invention;
FIG. 19 is a flowchart for explaining a compensation method according to a sixth embodiment of the present invention; FIG.
20 is a flowchart for explaining a compensation method according to a seventh embodiment of the present invention;
FIG. 21 is a flowchart for explaining a compensation method according to an eighth embodiment of the present invention; FIG.
22 is a flowchart for explaining a compensation method according to a ninth embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The organic light emitting display according to the present invention may be implemented in a top emission mode, a bottom emission mode, or a dual emission mode depending on the direction of light emission. Also, the display device according to the present invention can be implemented by navigation, a video player, a personal computer (PC), a wearable (watch, glasses, etc.), a mobile phone (smart phone)

FIG. 1 is a block diagram schematically showing an organic light emitting display device, and FIG. 2 is a schematic diagram showing a subpixel shown in FIG.

1, the organic light emitting display includes an image supply unit 1000, a timing control unit 170, a scan driving unit 150, a data driving unit 130, a display panel 110, and a power supply unit 140 .

The image supply unit 1000 processes the data signal and outputs it together with a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a clock signal, and the like. The image supply unit 1000 supplies a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a clock signal, and a data signal to the timing control unit 170.

The timing controller 170 receives a data signal and the like from the image supply unit 1000 and controls the operation timing of the data driver 130 and the gate timing control signal GDC for controlling the operation timing of the scan driver 150 And outputs a data timing control signal DDC. The timing controller 170 supplies a data signal DATA to the data driver 130 together with a data timing control signal DDC.

The scan driver 150 outputs a scan signal while shifting the level of the gate voltage in response to the gate timing control signal GDC supplied from the timing controller 170. The scan driver 150 includes a level shifter and a shift register. The scan driver 150 supplies the scan signals to the sub-pixels SP included in the display panel 110 through the scan lines GL1 to GLm. The scan driver 150 may be formed on the display panel 110 in the form of a gate in panel or an integrated circuit (IC). The portion of the scan driver 150 formed in a gate-in-panel manner is a shift register.

The data driver 130 samples and latches the data signal DATA in response to the data timing control signal DDC supplied from the timing controller 170 and converts the digital signal into an analog signal corresponding to the gamma reference voltage and outputs the analog signal . The data driver 130 supplies the data signals to the sub-pixels SP included in the display panel 110 through the data lines DL1 to DLn. The data driver 130 may be formed in the form of an integrated circuit (IC).

The power supply unit 140 generates a first power source EVDD and a second power source EVSS to be supplied to the display panel 110. The first power source EVDD corresponds to a high potential power source and the second power source EVSS corresponds to a low potential power source. The power supply unit 140 generates power to be supplied to the scan driver 150 and the data driver 130 as well as the power supplies EVDD and EVSS to be supplied to the display panel 110 based on the input power supplied from the outside.

The display panel 110 displays an image corresponding to the scan signal and the data signal output from the driving unit including the scan driver 150 and the data driver 130. The display panel 110 may be implemented as a flat plate, a curved surface, or a flexible plate depending on the material of the substrate. In the display panel 110, the sub-pixels SP positioned between the two substrates emit light in response to the driving current.

As shown in FIG. 2, one sub-pixel includes a switching transistor SW connected to (or formed at) an intersection of the scan line GL1 and the data line DL1 and the data supplied through the switching transistor SW And a pixel circuit (PC) that operates in response to a signal. The pixel circuit PC includes a circuit such as a driving transistor, a storage capacitor, an organic light emitting diode, and a compensation circuit for compensating the circuit.

The compensation circuit is a circuit for compensating the threshold voltage of the drive transistor and the like. The compensation circuit is composed of one or more thin film transistors, capacitors, and the like. The configuration of the compensation circuit is very various according to the compensation method, and a detailed illustration and description thereof are omitted. The thin film transistor is implemented based on low temperature polysilicon (LTPS), amorphous silicon (a-Si), oxide or organic semiconductor layers.

The organic light emitting display includes a display panel 110 and a display panel 110. The display panel 110 emits light based on scan signals and data signals output from the power supplies EVDD and EVSS output from the power supply unit 180 and the scan driver 130 and the data driver 140, A specific image is displayed.

FIG. 3 is a flow chart for explaining the conventional compensation method, FIG. 4 is an exemplary view of a conventional compensation method, FIG. 5 is a graph for explaining a luminance change according to a conventional compensation method, Which is a graph for explaining compensation errors according to the present invention.

As shown in FIGS. 3 to 6, a method of detecting deterioration of the organic light emitting diode (S110), generating compensation data (S120), and performing absolute compensation (S130) in a bottom- (See Figure 3).

According to the conventionally proposed method, the image data value of the degraded area is largely allocated by applying the gain data to the image data signal after generating the gain data for the degraded area. Accordingly, the organic light emitting diode recovers the previous luminance according to the compensation value, as shown in the luminance profile after the compensation before the compensation profile (see FIG. 4).

However, in the conventional method, the larger the degradation is, the larger the gain is applied (the more the degradation is progressed, the more the compensation gain is continuously increased (G1 -> G6)), so that the stress of the organic light emitting diode is increased . As a result, the organic light emitting diode is stressed to reduce the lifetime of the device. That is, the time required to reduce the luminance to 50% is shorter than when the compensation is not performed. (See Fig. 5)

In addition, it is difficult for the proposed method to reflect variations in the position of the display panel, and it is difficult to reflect various causes (various deterioration environmental conditions) other than the size of data applied to a specific pixel even if data is counted. As a result, compensation errors due to sensing noise and erroneous compensation (NG) are caused, and it is difficult to perform accurate compensation. (See Fig. 6)

Therefore, the conventionally proposed method increases the stress of the element by supplying more current to the element to compensate the brightness of the organic light emitting diode. As a result, the luminance of the organic light emitting diode temporarily appears to be compensated, but in the long term, the stress of the device is increased, and eventually, only the luminance reduction of the device is accelerated.

≪ Embodiment 1 >

FIG. 7 is a graph for explaining a deterioration model tracking method according to the first embodiment of the present invention. FIG. 8 is a graph for explaining the compensation concept according to the first embodiment of the present invention. 10 is a graph for explaining a parameter setting method according to the first embodiment, and FIGS. 10 and 11 are views for explaining a compensation example of the first embodiment of the present invention.

As shown in FIG. 7, the first embodiment of the present invention performs relative compensation using the degradation model tracking method of the organic light emitting diode. The deterioration model tracking method of an organic light emitting diode is a method of adjusting a parameter (a parameter of a stretched exponential decay model) of a stretched exponential decay model for predicting a deterioration life of an organic light emitting diode device, L / Lo).

As shown in FIG. 8, the first embodiment of the present invention compares the relative brightness, which varies with different stresses according to the positions of the organic light emitting diodes in the same luminance expression, with the target luminance, ). For example, the first embodiment of the present invention increases the gain when the current luminance of the organic light emitting diode existing in any first position is lower than the target luminance, but increases the current luminance such as the organic light emitting diode existing in any second position Is higher than the target luminance, the gain is lowered.

The first embodiment of the present invention differs from the first embodiment in that the gain is varied by the difference between the luminance of each position of the organic light emitting diode (the luminance deviation of each position in the same color or the same luminance expression) The weight of the gain is varied according to the position to compensate for the same luminance (refer to the current luminance after compensation) at all positions.

The parameters of the stretched exploded decay model described above are determined by reflecting current, temperature, and position information, which can be expressed by the following equation (1).

L0 (i, j) is the initial luminance per location,

L (i, j) is the current luminance per location,

τ (i, j) is a parameter that determines the rate of luminance reduction of the organic light emitting diode by position,

[theta] (i, j) is a parameter that determines the shape of the luminance reduction of the organic light emitting diode by position,

t denotes the time at which the luminance reduction proceeds.

As shown in FIG. 9 (a), the degree of deterioration of the organic light emitting diode can be estimated by modeling the current, temperature, and position information of the organic light emitting diode, and the degradation rate of the organic light emitting diode it means.

As shown in FIG. 9 (b),? Is a fixed value according to the characteristics of the organic light emitting diode, and the shape of the decrease is determined to about 50% luminance.

The first embodiment of the present invention compensates an afterimage, not deterioration of the organic light emitting diode, using the parameters described above. To this end, the first embodiment of the present invention can generate a luminance gain based on an average or a mode of a histogram for the entire area of the display panel. The target luminance is set to the average luminance of the entire area of the display panel at the current time, not the initial luminance.

Hereinafter, an example of a residual image compensation method of the organic light emitting diode according to the first embodiment of the present invention will be described with reference to FIGS. 10 and 11. FIG. In Fig. 10 and Fig. 11, for the sake of convenience of explanation, the entire area of the display panel is made up of 9 in total.

The average brightness and gain of the entire area of the display panel are obtained. Since the total area of the display panel is composed of 9 pieces, the average luminance and the gain for each area are obtained as follows.

- the average luminance of the entire area of the display panel -

L / Lo 1: 900, L / Lo 2: 780, L / Lo 3: 850,

L / Lo 4: 910, L / Lo 5: 850, L / Lo 6: 210,

L / Lo7: 340, L / Lo8: 877, L / Lo9: 716 = mean (L / Lo): 714.78

- Gain for the entire area of the display panel -

Gain1: 0.79, Gain2: 0.92, Gain3: 0.84,

Gain 4: 0.79, Gain 5: 0.84, Gain 6: 3.40,

Gain7: 2.10, Gain8: 0.82, Gain9: 0.99,

In the above example, if the initial luminance is 1000, the target luminance of the compensation is 714.78 instead of 1000. Therefore, the range of the luminance gain to be compensated is smaller than when the absolute compensation is taken.

As shown in FIG. 11, after the time T, the organic light emitting diode deteriorates deterioration with respect to the initial luminance in each region of the display panel. However, afterimage compensation of the organic light emitting diode according to the first embodiment of the present invention compensates for the same luminance (at all positions) in the entire area of the display panel.

Hereinafter, the compensation method according to the first embodiment of the present invention will be described in detail.

FIG. 12 is a flowchart for explaining a compensation method according to the first embodiment of the present invention. FIG. 13 is a view for explaining the difference between the conventional compensation method and the compensation method according to the first embodiment, And the difference between before and after compensation between the method and the first embodiment.

The image data supply step S210 is a step of receiving image data from the image supply unit or the like.

The current data conversion step S220 is a step of converting supplied image data into current data. When the image data is converted into the current data, data can be prepared which can detect the degree of deterioration of the organic light emitting diode.

The temperature and position data preparation step S235 is performed through experiments. Experimental data is required to eliminate or reduce these deviation values because display panels have process deviations. The temperature and position data information is provided as an experimental representative value that can be lowered to the process deviation in calculating the degree of deterioration of each organic light emitting diode included in the display panel and can be stored in a memory in the form of a lookup table .

The data information combining step S230 is a step of reflecting and combining current, temperature, and position information, which are parameters thereof, in order to construct a stretched exclusive decay model. The degradation degree of the organic light emitting diode can be predicted by providing the stretched personalized decay model reflecting the current, temperature, and positional information.

The stress data generation step S240 is a step of generating stress data based on a stretched exclusive decay model provided with current, temperature, and position data. The stress data is generated to track the relative luminance according to the stress received by the organic light emitting diode.

The relative luminance information conversion step S250 is a step of converting the stress data into relative luminance information. The stress data based on the stretched exponential decay model can obtain the relative luminance information that varies depending on different stresses depending on the positions of the organic light emitting diodes.

The target brightness setting step S255 is a step of setting the target relative brightness based on the relative brightness of the organic light emitting diodes and the average of the relative brightness of the entire display panel or the mode of the histogram.

The relative gain compensation value generating step S260 is a step of generating a relative gain compensation value for providing a luminance gain by a difference between the average of the relative luminance of the entire display panel (or the mode of the histogram) and the target relative luminance.

The compensated image data output step S270 is a step of compensating the image data by reflecting the relative gain compensation value to the currently supplied data and outputting the compensated image data.

In the first embodiment of the present invention, compensation values are applied while repeatedly performing the compensated image data output step (S270) from the image data supply step (S210), and the stress is continuously accumulated and the luminance change due to deterioration of the organic light emitting diode (Or tracking) the current luminance to perform relative compensation close to the current luminance. Therefore, since the stress due to the compensation acts less on the organic light emitting diode, the range of the gain compensation value does not increase over time.

The parts described in the first embodiment of the present invention are implemented by a logic circuit (algorithm) of a timing control section. The lookup table can be stored in a memory section (for example, an EEPROM) cooperating with a timing control section, A memory may be configured and interlocked with the timing controller.

As shown in Figs. 13A and 14A, absolute compensation is performed so as to approach the initial luminance. Therefore, there is a difference in the compensation range (gain compensation value) for each position, and a large deviation appears at a specific position. Accordingly, according to the conventional compensation method, the stress of the organic light emitting diode is heavily weighted depending on the position.

In addition, according to the conventional compensation method, as compensation is performed by performing absolute compensation, the gap between the life before and after the compensation and the luminance reduction rate becomes large. Also, according to the conventional compensation method, since the gain compensation value becomes larger, the bit resolution is reduced. And the more the compensation, the smaller the bit resolution, the more difficult it is to compensate precisely.

According to the first embodiment of the present invention, as shown in Figs. 13 (b) and 14 (b), relative compensation is performed so as to approach the current luminance. Therefore, although there may be slight differences in the compensation range (gain compensation value) by position, there is not a large variation. Thus, according to the first embodiment of the present invention, the stress of the organic light emitting diode is weighted and mitigated.

In addition, according to the compensation method of the first embodiment of the present invention, even when compensation is performed by performing the relative compensation, the gap between the life before and after the compensation and the luminance reduction rate hardly occurs. Further, according to the compensation method of the first embodiment of the present invention, it is possible to solve the problem that the gain compensation value becomes larger and the problem of the bit resolution being reduced. Since the bit resolution does not decrease much even if a lot of compensation is performed, detailed representation and precise compensation can be performed with a limited bit, and a large bit is not allocated for accurate compensation. That is, since the gain compensation value does not rapidly increase over time, gentle compensation performance can be maintained.

Therefore, since the compensation method of the first embodiment of the present invention does not compensate the luminance of the organic light emitting diode according to the initial luminance, it does not need to supply more current to the device, and the stress on the device can be lowered due to the compensation. As a result, it is possible to prevent and prevent the phenomenon that the luminance reduction of the device accelerates in the long term.

On the other hand, the compensation method according to the present invention is not limited to the above description, but can be achieved even if it follows the following flow or scheme. Hereinafter, other embodiments of the present invention will be described. In order to avoid duplication of the description, a description will be given mainly of the portions that differ from the first embodiment. Therefore, the parts omitted from the following description refer to the first embodiment.

FIG. 15 is a flowchart for explaining a compensation method according to a second embodiment of the present invention, FIG. 16 is a flowchart for explaining a compensation method according to the third embodiment of the present invention, FIG. 18 is a flowchart for explaining a compensation method according to a fifth embodiment of the present invention, FIG. 19 is a flowchart illustrating a compensation method according to the sixth embodiment of the present invention 20 is a flowchart for explaining a compensation method according to a seventh embodiment of the present invention, FIG. 21 is a flowchart for explaining a compensation method according to an eighth embodiment of the present invention, FIG. 22 is a flowchart 9 is a flowchart for explaining a compensation method according to a ninth embodiment of the present invention.

≪ Embodiment 2 >

As shown in Fig. 15, the compensation method according to the second embodiment of the present invention compensates in a manner similar to that of the first embodiment. However, in the second embodiment, stress data is generated using only current data.

To this end, the stress data generation step (S340) generates based on the current data. The after-image lifetime of the organic light-emitting diode is determined by the accumulation amount of the current applied to the device. Therefore, when the stress is accumulated, the stress data is generated by converting the input data into the current data and accumulating the current data.

≪ Third Embodiment >

As shown in Fig. 16, the compensation method according to the third embodiment of the present invention compensates in a manner similar to that of the first embodiment. However, in the third embodiment, stress data is generated using only voltage data, not current. The voltage data converts the input image data into voltage data according to the conversion formula.

To this end, after the voltage data conversion step S420, the stress data is generated based on the voltage data. The current flowing through the organic light emitting diode is controlled by a voltage applied to a driving transistor or the like serving as a valve. Accordingly, it can be known how much stress is accumulated in the organic light emitting diode by the voltage applied to the sub-pixel.

<Fourth Embodiment>

As shown in Fig. 17, the compensation method according to the fourth embodiment of the present invention compensates in a manner similar to that of the first embodiment. However, in the fourth embodiment, stress data is generated using the input amount of data without converting the input image data into a current.

To do this, the image data supplied from the outside is accumulated without going through the data conversion step, and stress data is generated based on the accumulated image data. The current applied to the organic light emitting diode can be adjusted to a voltage that is transmitted to the driving transistor or the like. The voltage transferred to the driving transistor determines the magnitude of the voltage depending on the input image data. Therefore, the stress data can be generated by accumulating the voltage or the current, but it can be derived even if the input image data is accumulated.

<Fifth Embodiment>

As shown in Fig. 18, the compensation method according to the fifth embodiment of the present invention compensates in a manner similar to that of the first embodiment. However, in the fifth embodiment, the stress data is accurately derived by reflecting all the characteristics of the display panel.

To do this, a step S610 of calculating all input image data (input amount of image data), voltage data, and current data is performed. The characteristics of the display panel are different for each panel, including positional deviation, temperature distribution deviation, and process-specific deviation. That is, even though the same voltage is applied to the entire area of the display panel, the brightness of the organic light emitting diode actually emitting light slightly differs.

It is possible to obtain a more accurate accumulation value by accumulating the stress data by assigning different weights to each position by analyzing information such as temperature and position corresponding to the unique characteristics of the display panel. That is, the compensation accuracy can be enhanced.

<Sixth Embodiment>

As shown in Fig. 19, the compensation method according to the sixth embodiment of the present invention compensates in a manner similar to that of the fifth embodiment. However, in the sixth embodiment, in order to increase the accuracy of the stress data generation, different weights are given according to the magnitude of the input value.

To this end, in the data information combining step S730, different weights are further reflected according to the size of input image data (input amount of image data), voltage data, and current data. Thus, the reason why the weight is given is that the accumulated relationship of the input image data, the voltage data, and the current data and the stress may not be linear. The weights previously set may be applied together with the temperature and position data, which are characteristics of the display panel, or may be applied independently.

<Seventh Embodiment>

As shown in Fig. 20, the compensation method according to the seventh embodiment of the present invention compensates in a manner similar to one of the first to sixth embodiments. However, in the seventh embodiment, a step of setting the average of the current relative luminance values to the target luminance is added.

To this end, a step S851 of setting the average of the current relative luminance values to the target luminance between the relative luminance information conversion step S850 and the target luminance setting step S855 is added. If the average of the current relative luminance value is set to the target luminance, the calculation burden is small and the luminance can be prevented from being changed abruptly when applying the afterimage compensation.

On the other hand, when the afterimage area is larger than the area having no afterimage, the average of the relative relative intensities is set to be very low and the brightness can be rather dark. In this case, the display panel may occur when the life span of the display panel is almost reached, which is not a problem in terms of afterimage compensation.

&Lt; Eighth Embodiment >

As shown in Fig. 21, the compensation method according to the eighth embodiment of the present invention compensates in a manner similar to one of the first to sixth embodiments. However, in the eighth embodiment, a step of setting the target brightness as the mode value is added.

To this end, the step S951 of setting the target luminance between the relative luminance information conversion step S950 and the target luminance setting step S955 as the mode value is added. The average of the area where the afterimage is generated and the area where no afterimage can occur may be slightly lower than the brightness when no afterimage occurs.

In this case, the compensation may cause the luminance to be slightly lowered. Therefore, if the target luminance is set to the mode value, the luminance of the region free from residual image is high, and therefore, the luminance after compensation can be prevented from being lowered even slightly.

&Lt; Example 9 &

As shown in Fig. 22, the compensation method according to the ninth embodiment of the present invention compensates in a manner similar to one of the first to eighth embodiments. However, in the ninth embodiment, a gain according to an image is added to the relative gain compensation value to reflect the changed characteristics of the driving transistor and the like to provide a gain compensation value.

To this end, a step of generating a gain according to an image to reflect the changed characteristics of the driving transistor (S1067) is performed. After the relative gain compensation value generation step (S1060), a gain according to the image is added to the relative gain compensation value (S1065).

The afterimage may be caused by the lifetime of the organic light emitting diode, but may be caused by the characteristics of the driving transistor and the like. That is, even if the lifetime of the organic light emitting diode is predicted, the afterimage may be noticeable even after the compensation if the changed characteristics of the transistor are not reflected even though it is compensated completely. However, if the gain is further applied to the image, the relative compensation gain can be adjusted (the compensation value is adjusted to be larger or smaller) and the compensating portion can be compensated by compensating the uncompensated portion of the transistor. .

As described above, the present invention compensates for the deterioration characteristics of the device depending on the position and performs consistent relative compensation over the entire area of the display panel, so that the degree of freedom of compensation is high and the compensation life is increased. In addition, the present invention compensates mainly for the afterimage and smudges occurring in the entire area of the display panel, rather than compensating for luminance reduction due to deterioration, thereby relieving stress applied to the device, thereby achieving long lifetime. Further, the present invention analyzes and reflects the deterioration factor of a device in units of subpixels, thereby enhancing the reliability of compensation results. Further, since the present invention does not require a sensing circuit for compensation, the circuit and the layout of the subpixel can be simplified.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

1000: image supply unit 170: timing control unit
150: scan driver 130:
110: display panel 140: power supply unit

Claims (10)

A display panel for displaying an image;
A driving unit for driving the display panel; And
And a timing controller for compensating the data signal so that the same luminance is displayed at all positions by varying the weight of the gain when the luminance deviation for each position is predicted using the organic light emitting diode included in the display panel, Display device. The method according to claim 1,
The timing control unit
Wherein the gain of the organic light emitting diode is increased when the current luminance of the organic light emitting diode is lower than the target luminance and the gain is lowered when the current luminance of the organic light emitting diode is higher than the target luminance. The method according to claim 1,
The timing control unit
The organic light emitting display device according to claim 1, wherein the organic light emitting diode (OLED) includes a plurality of organic light emitting diodes (OLED). 3. The method of claim 2,
The timing control unit
And compensates the gain based on an average or a mode of a histogram for the entire area of the display panel. 5. The method of claim 4,
The timing control unit
The target luminance is set to the average luminance of the entire area of the display panel at the current time instead of the initial luminance, the gain is increased if the current luminance of the organic light emitting diode is lower than the target luminance, and the current luminance of the organic light emitting diode is higher than the target luminance And the gain is lowered when the gain is higher. The method of claim 3,
The timing control unit
Wherein the image data is converted into one of an input amount of image data input from the outside, voltage data obtained by converting the image data into a voltage, current data obtained by converting the image data into a current, Wherein the weighting unit assigns different weights according to at least one of a magnitude of the voltage data or a magnitude of the current data. Preparing data by modeling the degree of deterioration of the organic light emitting diode according to temperature and position through experiments;
Generating stress data based on image data input from the outside and degree of deterioration by temperature and position;
Converting the stress data into relative luminance information of the organic light emitting diode;
Setting a target relative brightness based on an average of relative brightness of the entire display panel or a mode of a histogram; And
And providing a gain corresponding to the difference between the average of the relative luminance of the entire display panel or the mode of the histogram and the target relative luminance. 8. The method of claim 7,
In the step of generating the stress data
Based on at least one of a magnitude of an input amount of image data input from the outside, a magnitude of voltage data obtained by converting the image data into a voltage, a magnitude of current data obtained by converting the image data into a current, and a degree of deterioration And generating the stress data. 9. The method of claim 8,
In the step of providing the gain
Wherein the weight of the gain is varied based on one of an input amount of the image data, a size of the voltage data, and a size of the current data. 10. The method of claim 9,
In the step of providing the gain
Wherein the gain of the organic light emitting diode is increased when the current luminance of the organic light emitting diode is lower than the target luminance and the gain is lowered when the current luminance of the organic light emitting diode is higher than the target luminance.

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