KR100762692B1 - OLED display device and driving method thereof - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic light emitting display device and a method of driving the same, which reduces power consumption and improves image quality by limiting the amount of current flowing when the area expressing high brightness is large in the entire light emitting area. It is.

According to an embodiment of the present invention, a pixel unit includes a plurality of scan signals, a plurality of emission control signals, and a plurality of data signals to represent an image, a frame memory configured to store and output the video data in units of one frame section, and the pixels. A scan driver which transmits the scan signal and the emission control signal to a unit, a data driver which receives the video data from the frame memory, generates the plurality of data signals, and transmits the plurality of data signals to the pixel unit, and the video stored in the frame memory And a luminance controller configured to determine a limited width of luminance by using the sum of the data, wherein the luminance controller generates a sum of the video data obtained by summing the video data in one frame period, and the sum of the video data is greater than or equal to a predetermined value. If it is, the brightness of the pixel portion is limited, and the video To the sum of the data provides an organic light emitting display is lower than a predetermined value that does not limit the brightness of the pixel unit device.

Description

Organic light emitting display device and driving method thereof {ORGANIC LIGHT EMITTING DISPLAY AND DRIVING METHOD THE SAME}

1 is a structural diagram showing a light emitting display device according to the prior art.

2 is a structural diagram showing a structure of a light emitting display device according to the present invention.

3 is a structural diagram showing an example of a luminance control unit employed in the light emitting display device according to the present invention.

4A to 4D illustrate a case where the light emission ratio of the light emission signal input to the light emitting display device according to the present invention is limited to a maximum of 33%.

5A to 5D illustrate a case in which the light emission ratio of the light emission signal input to the light emitting display device according to the present invention is limited to a maximum of 50%.

*** Explanation of symbols on main parts of drawings ***

100: pixel portion 110: pixel

200: luminance controller 210: first data summing unit

220: memory unit 230: second data summing unit

240: lookup table 250: luminance control driver

260: frame memory 300: data driver

400: scan driver 500: power supply

The present invention relates to an organic light emitting display device and a driving method thereof. More specifically, the present invention relates to an organic light emitting display for reducing power consumption and improving image quality by determining a limited width of luminance corresponding to a sum of data input to a pixel unit. A display device and a driving method thereof are provided.

Recently, various flat panel display devices having a smaller weight and volume than the cathode ray tube have been developed. In particular, a light emitting display device having excellent luminous efficiency, brightness, viewing angle, and fast response speed has been attracting attention.

The organic light emitting diode is also referred to as an organic light emitting diode (OLED), and includes an anode, a cathode, and an organic light emitting layer disposed therebetween to emit light by a combination of electrons and holes.

1 is a structural diagram showing a light emitting display device according to the prior art. Referring to FIG. 1, the light emitting display device according to the related art includes a pixel unit 10, a data driver 20, a scan driver 30, and a power supply 40.

In the pixel unit 10, a plurality of pixels 11 are arranged and a light emitting element (not shown) is connected to each pixel 11. And n scan lines S1, S2, ... Sn-1, Sn formed in the row direction and transmitting the scan signals, and m data lines D1, D2, formed in the column direction and transferring the data signals. M m power supplies for transmitting the first power supply (Dm-1, Dm) and the first power supply (not shown) and the second power supply ELVss having a lower potential than the first power supply (ELVdd). 2 power supply lines (not shown) are arranged. The pixel unit 10 emits light by the scan signal, the data signal, the first power source ELVdd, and the second power source ELVss to display an image.

The data driver 20 is a means for applying a data signal to the pixel unit 10. The data driver 20 is connected to the data lines D1, D2,... Dm-1, Dm of the pixel unit 10. Connected to apply a data signal to the pixel portion 10.

The scan driver 30 is a means for sequentially outputting scan signals. The scan driver 30 is connected to the scan lines S1, S2,... Pass in a line. The data signal input from the data driver 20 is applied to a specific row of the pixel unit 10 to which the scan signal is transmitted to display an image. When all rows are sequentially selected, one frame is completed.

The power supply unit 40 transmits the first power source ELVdd and the second power source ELVss having a lower potential than the first power source ELVdd and the first power source ELVdd and the second power source ELVdd to the pixel unit 10. Due to the voltage difference of ELVss, a current corresponding to the data signal flows in each pixel 10.

In the light emitting display device configured as described above, when the image represented by the pixel portion 10 includes a large number of pixels expressing high brightness, a large amount of current flows in the pixel portion 10 and the image represented by the pixel portion 10. When a large number of pixels expressing this low luminance are included, a small current flows in the pixel portion 10.

At this time, when a large number of pixels 10 expressing high luminance are included and a large amount of current flows in the pixel portion 10, a large load is applied to the power supply 40, so that the power supply 40 needs to have a high output. There is a problem.

In addition, when a large amount of pixels 10 expressing low luminance is included and a small current flows in the pixel portion 10, the luminance difference between the brightest and the darkest luminance is small, resulting in a low contrast of the organic light emitting display device. There is this.

Therefore, the present invention was created to solve the problems of the prior art, an object of the present invention is to limit the amount of current corresponding to the sum of the data input in the interval of one frame to reduce the power consumption, easy to recognize Provided is an organic light emitting display device and a driving method thereof, in which one image has a larger limit and an image that is not easily recognized has a smaller limit so that the contrast can be increased so that a user can easily recognize the image and improve the image quality. will be.

In order to achieve the above object, a first aspect of the present invention includes a pixel unit including pixels representing an image by receiving a plurality of scan signals, a plurality of emission control signals, and a plurality of data signals; A frame memory for storing and outputting video data in units of one frame section; A scan driver transferring the scan signal and the emission control signal to the pixel unit; A data driver which receives the video data from the frame memory and generates the plurality of data signals and transmits the plurality of data signals to the pixel unit; And a luminance controller configured to determine a limited width of luminance by using the sum of the video data stored in the frame memory, wherein the frame memory stores video data corresponding to the total number of pixels of the pixel portion, When the video data of less than the number of pixels is input, only the input video data is updated and the rest is maintained. The luminance controller generates a total of the video data obtained by adding the video data in one frame period. An organic light emitting display device is provided in which the luminance of the pixel portion is limited when the sum total is equal to or greater than a predetermined value, and the luminance of the pixel portion is not limited when the sum total of the video data is equal to or less than the predetermined value.

According to a second aspect of the present invention, there is provided a display apparatus including: a pixel unit including pixels configured to express an image by receiving a plurality of scan signals, a plurality of emission control signals, and a plurality of data signals; A scan driver transferring the scan signal and the emission control signal to the pixel unit; A data driver which generates the plurality of data signals using video data and transmits the plurality of data signals to the pixel unit; A frame memory which stores the video data in units of one frame section and transmits the video data to the data driver; And a luminance control unit for limiting the luminance of the pixel unit if the sum of the video data stored in the frame memory is greater than or equal to a predetermined value, and not for limiting the luminance of the pixel unit if the sum is less than or equal to a predetermined value. Stores video data corresponding to the number of pixels, and if less video data is input than the total number of pixels of the pixel unit, only the input video data is updated and the rest is maintained, and the luminance controller controls the video in one frame section. The present invention provides an organic light emitting display device which generates a total sum of video data obtained by adding data, and sets a range in which the luminance of the pixel portion is limited according to the total sum of the video data.

According to a third aspect of the present invention, the video data is transferred to a frame memory to store video data corresponding to an interval of one frame, and the frame memory stores video data corresponding to the total number of pixels of the pixel portion, and the total of the pixel portion. Updating only the input video data when the number of video data smaller than the number of pixels is input; Summing video data stored in the frame memory to determine a total sum of video data input in one frame period; And a method of driving an organic light emitting display device for limiting luminance of a pixel portion in correspondence with the total size of the video data.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

2 is a structural diagram showing a structure of a light emitting display device according to the present invention. Referring to FIG. 2, the light emitting display device includes a pixel unit 100, a frame memory 200, a luminance controller 250, a data driver 300, a scan driver 400, and a power supply 500. .

In the pixel unit 100, a plurality of pixels 110 are arranged and a light emitting element (not shown) is connected to each pixel 110. And n scan lines S1, S2, ... Sn-1, Sn that are formed in a row direction and transmit scan signals, and n light emission control signal lines E1, E2, ... En that transfer emission control signals. -1, En), m data lines D1, D2, .... Dm-1, Dm formed in the column direction and transmitting the data signal, and a first power source delivering the first power source ELVdd to the pixel. The line L1 and the second power line L2 for transmitting the second power source ELVss to the pixel are arranged. In this case, the second power supply line L2 is equivalently represented and may be formed in the entire area of the pixel unit 100 to be electrically connected to each pixel 110.

The frame memory 200 receives video data and stores video data corresponding to a section of one frame so that the video data is transmitted to the data driver in units of frames. In this case, as many video data as the number of pixels included in the pixel unit 100 are stored in the frame memory 200. The number of video data transferred to the frame memory 200 may be transferred as the number of pixels. Less than the number of pixels can be delivered. When the number of video data is transferred by the number of pixels, the displayed screen is changed to a new screen different from the previous screen or contains more video data than the previous screen, and the number of video data is smaller than the number of pixels. In the case of being delivered, the expressed screen is less changed than the previous screen or the previous frame is maintained.

When the video data inputted when the number of video data is smaller than the number of pixels is added, the video data is added to the number less than the number of video data represented on the actual screen, and the total size of the video data is reduced. If the total size of the smaller video data is used, there is a problem in that it is limited to a range smaller than the range to be actually limited.

Therefore, in order to solve the above problems, the sum of the video data is obtained using the video data stored in the frame memory 200.

When the video data of less than the number of pixels is transferred, the frame memory 200 updates the changed part with new video data and retains the previous video data in the unchanged part. Therefore, the frame memory 200 continues to store the same number of video data as the number of pixels.

In this case, when the sum of video data is obtained using the video data stored in the frame memory 200, if one number is transferred as the number of pixels of the pixel unit 100, the sum of the video data transferred to the frame memory is summed to obtain the sum of the video data. The magnitude can then be used to determine the limit of brightness.

The luminance controller 250 outputs a luminance control signal to limit the luminance so that the luminance of the pixel unit 100 representing the image does not exceed a predetermined level. In other words, the case where the size of the video data stored in the frame memory 200 is large is higher than the case where the area emitting light with high luminance is small in the pixel unit 100. Accordingly, the luminance controller 250 increases the luminance limit when the sum of the video data stored in the frame memory 200 is large and the sum of the video data stored in the frame memory 200 is small. Reduce the limit of luminance.

For example, when the pixel unit 100 emits light in full white, the pixel unit 100 has higher luminance than otherwise. Therefore, as described above, when the pixel unit 100 emits light with high luminance, the limit of brightness is increased, and when the pixel unit 100 emits light with low luminance, the limit of brightness is reduced and the video data stored in the frame memory 200 is reduced. The luminance is adjusted to correspond to the sum of the video data by varying the luminance limit range according to the sum.

The luminance controller 250 determines the total amount of video data input in one frame, and determines that the amount of current flowing to the pixel unit 100 that emits light brightly when its size is large and flows to the pixel unit 100 when its size is small. It is judged that the amount of current is small. Therefore, the luminance controller 250 outputs a luminance control signal for limiting the luminance when the total amount of video data is greater than or equal to a predetermined value, thereby reducing the overall brightness of the image represented by the pixel unit 100 to display the luminance control signal. .

When the luminance of the pixel unit 100 is limited by the luminance controller 250, the amount of current flowing in the pixel unit 100 is limited, thereby eliminating the need for a high output power supply unit 500. In addition, when the luminance of the pixel unit 100 is not limited, the time for emitting the pixels to emit light is maintained for a long time, thereby increasing the luminance, thereby increasing the contrast ratio of the pixels to emit light and the pixels not to emit light. Therefore, when the light is not emitted at low brightness, the limit of the brightness is not small or the brightness is not limited, so the contrast ratio of the pixel unit 100 is improved.

In this case, as a method of reducing the amount of current flowing in the pixel portion 100, when the pixel emits light, the amount of current flowing in the pixel portion 100 may be reduced by reducing the time for supplying the current.

The luminance controller 250 adjusts the pulse width of the emission control signal transmitted through the emission control signal lines E1, E2, ... En-1, En to adjust the time for which the pixel unit 100 emits light. If the pulse width is long by adjusting the light emission time to emit light in the frame, the amount of current flowing into the pixel portion 100 increases, so that the overall luminance of the pixel portion 100 does not decrease. ), The amount of current flowing in is reduced so that the overall luminance of the pixel portion 100 is lowered.

Accordingly, in order to solve the above problem, the frame memory 200 is divided into a plurality of areas, and the video data is changed and transferred, and the size is stored, and the video data is not changed and the previous data is not transferred. This problem is solved by grasping the size to obtain the sum of video data represented on one screen.

The data driver 300 is a means for applying a data signal to the pixel unit 100. The data driver 300 receives video data having red, blue, and green components from the frame memory 200 to generate a data signal. The data driver 300 applies the data signal generated by being connected to the data lines D1, D2,... Dm-1, Dm of the pixel unit 100 to the pixel unit 100.

The scan driver 400 is a means for applying a scan signal and a light emission control signal to the pixel unit 100. The scan driver 400 is a scan line S1, S2, ... Sn-1, Sn and a light emission signal line E1. , E2, ... En-1, En) to transmit a scan signal and a light emission control signal to a specific row of the pixel unit 100. The data signal output from the data driver 300 is transmitted to the pixel 110 to which the scan signal is transmitted, and the pixel 110 to which the emission control signal is transmitted emits light according to the emission control signal. In addition, the emission control signal is controlled by the luminance controller 250 to adjust the emission time of the pixel 110.

The scan driver 400 may be divided into a scan driver circuit for generating a scan signal and a light emitting driver circuit for generating a light emission control signal, and the scan driver circuit and the light emitting driver circuit may be included in one component part and may be separate. It may be separated into components.

The data signal input from the data driver 300 is applied to a specific row of the pixel unit 100 to which the scan signal is transmitted, and a current corresponding to the data signal is transferred to the light emitting control signal so that the image is emitted by the light emitting device. Is displayed. At this time, if all the rows are sequentially selected, one frame is completed.

The power supply unit 500 transfers the first power source ELVdd and the second power source ELVss to the pixel unit 400, and thus, the data signal of each pixel is changed by the difference between the first power source ELVdd and the second power source ELVss. Allow current to flow. In addition, the power supply unit 500 causes a larger current to flow when emitting light with high brightness in each pixel than when emitting light with low brightness in each pixel, and when a larger current flows, power consumption increases.

3 is a structural diagram showing a connection relationship between a luminance controller and a frame memory employed in the light emitting display device according to the present invention. Referring to FIG. 3, the luminance controller 250 includes a data summing unit 260, a lookup table 270, and a luminance control driver 280. The data summing unit 260 receives video data from the frame memory 200.

The frame memory 200 receives and stores video data in units of sections of one frame. In the frame section, as many video data as the number of pixels included in the pixel unit 100 are stored.

The data summing unit 260 sums the video data stored in the frame memory 200. In general, if the video data having a high gray value is larger than the video data having a low gray value and the sum of the video data is large, it is determined that many video data having a high gray value are represented on one screen. If the sum is small, it is determined that video data having a high gray value is less represented on one screen. In addition, when a large amount of video data having a high gray value is included, a large current flows in the pixel unit 100, so that the power supply unit 500 needs to have a high output, and thus a lot of video data having a high gray value is included. If so, the luminance is limited to limit the amount of current flowing through the pixel portion 100.

In the lookup table 270, the width of the light emission section of the light emission control signal is designated according to a data value indicating the total amount of video data summed by the data summing unit 230. At this time, the width of the light emitting section is specified using the upper bits of the data representing the total sum of the video data. By using the upper five bits of the sum of the video data, it is possible to determine the degree of brightness of the pixel unit 100 in one frame.

As the sum of the sum of the video data increases, the luminance of the pixel unit 100 gradually increases, and the luminance of the pixel unit 100 is limited when the brightness of the pixel unit 100 reaches a predetermined brightness or more. In addition, as the luminance of the pixel unit 100 increases, a ratio that is gradually limited is further increased to prevent an excessive increase in the luminance of the pixel unit 100.

At this time, if the luminance is uniformly limited in accordance with the increase in the luminance of the pixel portion 100, the luminance of the pixel portion 100 may be excessively limited by the limitation of the luminance when the luminance is very high. It doesn't provide a bright screen and simply drops the overall brightness. Therefore, by setting a range that limits the luminance to the maximum, a range that is limited when the entire pixel portion 100 represents white is prevented from falling below a range that limits the luminance limitation of the pixel portion 100.

In this case, the image displayed in the light emitting display device may be classified into a case of a still image and a case of a moving image, and thus the restriction range may be changed according to the type of image.

When the sum of the video data does not exceed the predetermined size, the luminance is not limited. When the luminance is not high, the luminance is not limited.

Table 1 shows a look-up table 270 in which the emission ratio, that is, the ratio between the predetermined interval and the interval in which the luminance is emitted within one frame period, is limited to 50% of the maximum value according to the luminance of the pixel unit 100. The predetermined section may be a section of one frame or a section shorter than that.

High 5 bit value Emission rate Luminous rain Luminance Light emission control signal width 0 0% 100% 300 325 One 4% 100% 300 325 2 7% 100% 300 325 3 11% 100% 300 325 4 14% 100% 300 325 5 18% 100% 300 325 6 22% 100% 300 325 7 25% 100% 300 325 8 29% 100% 300 325 9 33% 100% 300 325 10 36% 100% 300 325 11 40% 99% 297 322 12 43% 98% 295 320 13 47% 96% 287 311 14 51% 93% 280 303 15 54% 89% 268 290 16 58% 85% 255 276 17 61% 81% 242 262 18 65% 76% 228 247 19 69% 72% 217 235 20 72% 69% 206 223 21 76% 65% 196 212 22 79% 62% 186 202 23 83% 60% 179 194 24 87% 57% 172 186 25 90% 55% 165 179 26 94% 53% 159 172 27 98% 51% 152 165 28 - - - - 29 - - - - 30 - - - - 31 - - - -

Table 1 is preferably applied when the image is a still image. The luminance is not limited when the emission rate of the pixel unit 100 is 36% or less, and the luminance is applied when the emission area ratio exceeds 36%. If the area that emits light at the maximum brightness is increased, the ratio of limiting the brightness is also increased. In this case, the emission rate is a variable determined by Equation (1).

In order to prevent the brightness from being excessively limited, the maximum emission rate is set to 50% so that even if most of the pixels in the pixel portion 100 emit light at the maximum brightness, the ratio of limiting the brightness is not 50% or less. .

In Table 1, the light emission rate of 0% does not mean that the light emission does not occur, but indicates that the upper five bits are zero because the luminance of one frame is emitted below a predetermined value.

Table 2 shows a lookup table 270 in which the luminance is limited to a maximum of 33% by setting the maximum value of the emission rate to 33% according to the luminance of the pixel unit 100.

High 5 bit value Emission rate Luminous rain Luminance Light emission control signal width 0 0% 100% 300 325 One 4% 100% 300 325 2 7% 100% 300 325 3 11% 100% 300 325 4 14% 100% 300 325 5 18% 99% 298 322 6 22% 98% 295 320 7 25% 95% 285 309 8 29% 92% 275 298 9 33% 88% 263 284 10 36% 83% 250 271 11 40% 79% 237 257 12 43% 75% 224 243 13 47% 70% 209 226 14 51% 64% 193 209 15 54% 61% 182 197 16 58% 57% 170 184 17 61% 53% 160 173 18 65% 50% 150 163 19 69% 48% 143 155 20 72% 45% 136 147 21 76% 43% 130 141 22 79% 41% 124 134 23 83% 40% 119 128 24 87% 38% 113 122 25 90% 36% 109 118 26 94% 35% 104 113 27 98% 34% 101 109 28 - - - - 29 - - - - 30 - - - - 31 - - - -

Table 2 is preferably applied when the video is a moving image. If the emission rate is less than 34%, the luminance is not limited. If the emission rate is more than 34%, the area emitting light at the maximum luminance is limited. Increasing will also increase the rate of limiting luminance. In order to prevent the brightness from being excessively limited, the maximum limiting ratio is set to 33% so that even if most of the pixels of the pixel portion 100 emit light at the maximum brightness, the rate limiting luminance is not lower than 33%.

The brightness control driver 280 receives the upper 5 bit values of the sum of the video data and outputs the brightness control signal. The luminance control signal is input to the scan driver 400 to control the scan driver 400 to output the light emission control signal according to the luminance control signal from the scan driver 400. In particular, when the scan driver 400 is divided into a scan driver circuit and a light emission control circuit, the brightness control signal is input to the light emission control circuit and outputs a light emission control signal according to the brightness control signal.

In the light emission control signal, the maximum light emission period is set to 325. Therefore, 8 bits can represent 256 types and 9 bits can represent 512 types. Therefore, in order to generate light emitting sections of the light emitting control signals shown in Table 1, it is preferable that the luminance control signals output 9 bits of signals. Do. The pulse width of the start pulse input to the scan driver may be adjusted by the luminance control signal, and the width of the emission control signal may be determined according to the change of the width of the start pulse.

4A to 4D illustrate a case where the light emission ratio of the light emission signal input to the light emitting display device according to the present invention is limited to a maximum of 33%. Fig. 4A shows the relationship between the calculated luminance ratio and the luminance ratio, and Fig. 4B shows the measured values of the luminance ratio and the luminance ratio actually measured. 4C shows the relationship between the calculated light emission rate and the current ratio, and FIG. 4D shows the relationship between the measured light emission rate and the current ratio.

Referring to FIGS. 4A and 4B, when the light emission rate is within about 30%, the luminance is maintained at a constant level so that the screen is not darkened, and when the light emission rate is about 30% or more, the brightness is gradually decreased and expressed too brightly. To prevent glare.

Referring to FIGS. 4C and 4D, when the brightness is limited, the current flows from about 30 to 35% of the amount of current flowing when the brightness is not limited, thereby reducing the load on the power supply 500. The supply unit 500 does not require high output.

5A to 5D illustrate a case in which the light emission ratio of the light emission signal input to the light emitting display device according to the present invention is limited to a maximum of 50%. Fig. 5A shows the relationship between the calculated luminance ratio and the luminance ratio mathematically, and Fig. 5B shows the measured values of the luminance ratio and the luminance ratio actually measured. 5C shows the relationship between the calculated light emission rate and the current ratio, and FIG. 5D shows the relationship between the measured light emission rate and the current ratio.

Referring to FIGS. 5A and 5B, when the emission rate is less than about 40%, the luminance is maintained at a constant level so that the screen is not darkened. When the emission rate is about 40% or more, the brightness is gradually decreased to be too bright. The glare can be prevented by preventing the expression.

Referring to FIGS. 5C and 5D, when the brightness is limited, the current flows up to about 50% of the amount of current flowing when the brightness is not limited, thereby reducing the load on the power supply 500 to reduce the load on the power supply unit. 500) does not require high power.

While preferred embodiments of the present invention have been described using specific terms, such descriptions are for illustrative purposes only and it is understood that various changes and modifications may be made without departing from the spirit and scope of the following claims. You must lose.

According to the light emitting display device and the driving method thereof according to the present invention, it is possible to reduce the power consumption by limiting the flow of current in accordance with the light emission rate of the light emitting display device, to improve the image quality and to eliminate the need for a high output power supply.

Claims (12)

A pixel unit including pixels representing an image by receiving a plurality of scan signals, a plurality of emission control signals, and a plurality of data signals; A frame memory for storing and outputting video data in units of one frame section; A scan driver transferring the scan signal and the emission control signal to the pixel unit; A data driver which receives the video data from the frame memory and generates the plurality of data signals and transmits the plurality of data signals to the pixel unit; And A luminance controller configured to determine a limited width of luminance by using the sum of the video data stored in the frame memory; The frame memory stores video data corresponding to the total number of pixels of the pixel portion, and when less video data is input than the total number of pixels of the pixel portion, only the input video data is updated and the rest is maintained. The luminance controller generates a total sum of the video data obtained by summing the video data in one frame period, and when the sum of the video data is greater than or equal to a predetermined value, limits the luminance of the pixel unit, and the sum of the video data is a predetermined value. The organic light emitting display device which does not limit the luminance of the pixel portion below. A pixel unit including pixels representing an image by receiving a plurality of scan signals, a plurality of emission control signals, and a plurality of data signals; A scan driver transferring the scan signal and the emission control signal to the pixel unit; A data driver which generates the plurality of data signals using video data and transmits the plurality of data signals to the pixel unit; A frame memory which stores the video data in units of one frame section and transmits the video data to the data driver; And If the sum of the video data stored in the frame memory is a predetermined value or more includes a brightness control unit for limiting the brightness of the pixel portion, if the predetermined value or less, does not limit the brightness of the pixel portion, The frame memory stores video data corresponding to the total number of pixels of the pixel portion, and when less video data is input than the total number of pixels of the pixel portion, only the input video data is updated and the rest is maintained. The luminance controller generates a total sum of video data obtained by adding the video data in one frame period, and a range in which the luminance of the pixel unit is limited is set differently according to the total sum of the video data. delete The method according to claim 1 or 2, And a luminance of the pixel portion adjusted by a width of the emission control signal. The method according to claim 1 or 2, The brightness control unit, A data summing unit configured to receive video data corresponding to one frame section from the frame memory and add the video data to obtain a sum of video data input in the one frame section; A lookup table that stores light emission information on a light emission time of the pixel corresponding to data corresponding to the sum of the video data; And And a brightness control driver for transmitting a brightness control signal for controlling the light emission control signal according to the light emission information. The method of claim 5, And the scan driver receives the luminance control signal and generates the emission control signal. The method of claim 6, And the scan driver is divided into a scan driver circuit for transmitting the scan signal and a light emitting control driver circuit for transmitting the light emission control signal. The method according to claim 1 or 2, An organic light emitting display device according to an embodiment, wherein the luminance is limited according to the gradation voltage of the data signal. Video data is transmitted to a frame memory to store video data corresponding to an interval of one frame, and the frame memory stores video data corresponding to the total number of pixels of the pixel portion, and the video data of the pixel portion is smaller than the total number of pixels of the pixel portion. Updating only the input video data when is input; Summing video data stored in the frame memory to determine a total sum of video data input in one frame period; And And a brightness limit of the pixel portion in correspondence with the total size of the video data. The method of claim 9, And a light emission time at which the pixel portion emits light corresponding to the total size of the video data. The method of claim 9, And determining a light emission time at which the pixel light is emitted using a look-up table in which the light emission time at which the pixel light corresponding to the sum of the video data is emitted is stored. The method of claim 9, And transmitting the video data to the frame memory and then to the data driver in the frame memory.

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