KR20200015292A - Organic light emitting display apparatus and driving method thereof - Google Patents

Abstract

Embodiments of the present invention may provide a display device capable of preventing that the image quality is deteriorated. The display device comprises: a display panel including a plurality of pixels connected to a gate line and data line, wherein the gate line and data line cross each other; a data processing unit dividing the display panel into a plurality of areas, setting compensation gain for each area, compensating an input image signal corresponding to the compensation gains, and supplying a compensation image signal; a gate drive circuit applying a gate signal to the gate line; a data drive circuit applying a data signal to the data line corresponding to the compensation image signal; and a control unit controlling the gate drive circuit and data drive circuit and receiving the compensation image signal from the data processing unit to provide the compensation image signal to the data drive circuit.

Description

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

Embodiments of the present invention relate to an organic light emitting display device and a driving method thereof.

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

The organic light emitting diode includes an adone electrode, a cathode electrode and an organic compound layer formed therebetween. The organic compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer (ETL). EIL). When a driving voltage is applied to the anode electrode and the cathode electrode, holes passing through the HTL and electrons passing through the ETL move to the emission layer EML to form excitons, and as a result, the emission layer EML Can generate visible light.

The organic light emitting diode display employing the organic light emitting diode includes an organic light emitting diode in each pixel, and brightness can be adjusted by adjusting the amount of driving current flowing through the organic light emitting diode according to the gray level of video image data. However, as the light emitting time elapses, the organic light emitting diode increases the operating point voltage (threshold voltage) of the organic light emitting diode, which may cause deterioration in luminous efficiency. In addition, when deterioration occurs, the luminance is lowered, so that unevenness is displayed, thereby deteriorating the image quality, thereby degrading the life of the display apparatus.

An object of the present embodiments is to provide an organic light emitting display device and a method of driving the same, which can increase deterioration by suppressing deterioration.

Another object of the present embodiments is to provide an organic light emitting display device and a method of driving the same, which can prevent a deterioration of image quality.

In an aspect, embodiments of the present invention provide a display panel including a plurality of pixels in which a gate line and a data line cross each other, and a display panel including a plurality of pixels connected to the gate line and the data line. A data processor for setting a correction gain and correcting an input video signal in response to the correction gain to supply a correction video signal, a gate drive circuit applying a gate signal to the gate line, and applying a data signal to the data line in response to the correction video signal An organic light emitting display device may include a control unit configured to control a data drive circuit, a gate drive circuit, and a data drive circuit, and to receive a corrected image signal from a data processor and to supply the corrected image signal to a data drive circuit.

In another aspect, embodiments of the present invention include calculating a cumulative current amount for each of a plurality of areas of a display panel, setting a correction gain for each area corresponding to the cumulative current amount, and correcting an input image signal corresponding to the correction gain. A method of driving an organic light emitting display device may include generating a corrected image signal and driving a display panel in response to the corrected image signal.

According to embodiments of the present invention, it is possible to provide an organic light emitting display device and a driving method thereof that can increase deterioration by suppressing degradation.

Further, according to embodiments of the present invention, an organic light emitting display device and a driving method thereof that can prevent deterioration of image quality are provided.

1 is a structural diagram illustrating an embodiment of an organic light emitting display device according to embodiments of the present invention.
FIG. 2 is a circuit diagram illustrating an exemplary embodiment of the subpixel illustrated in FIG. 1.
3 is a plan view illustrating a display panel divided into a plurality of regions.
4 is a graph showing a ratio of luminance and current.
5A to 5C are graphs illustrating a method of setting local gain in the data processor illustrated in FIG. 1.
6 is a graph illustrating an embodiment of a diffusion coefficient.
Figure 7a shows an example of the diffusion coefficient of the 3x3 form.
7B illustrates an example of local gain set in the display panel.
FIG. 7C shows the luminance reduction amount in each region due to the local gain of FIG. 7B.
7D shows the luminance reduction amount diffused by the local gain to which the diffusion coefficient is applied.
FIG. 8 is a graph illustrating a first peak luminance and a second peak luminance set in the data processor illustrated in FIG. 1.
9 is a structural diagram illustrating a first embodiment of the data processing unit shown in FIG. 1.
FIG. 10 is a structural diagram illustrating a second embodiment of the data processing unit shown in FIG. 1.
11A and 11B are timing diagrams illustrating an embodiment of a data signal changed by the PWM control signal shown in FIG. 10.
12 is a timing diagram illustrating a process of changing from a first peak luminance to a second peak luminance.
FIG. 13 is a flowchart illustrating a method of driving the organic light emitting display device illustrated in FIG. 1.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only to distinguish the components from other components, and the terms are not limited in nature, order, order or number of the components. When a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but between components It will be understood that the elements may be "interposed" or each component may be "connected", "coupled" or "connected" through other components.

1 is a structural diagram illustrating an embodiment of an organic light emitting display device according to embodiments of the present invention.

Referring to FIG. 1, the organic light emitting diode display 100 may include a display panel 110, a gate drive circuit 120, a data drive circuit 130, a controller 140, and a data processor 150.

In the display panel 110, a plurality of subpixels 101 may be disposed in a region where a plurality of gate lines G1,..., Gn and a plurality of data lines D1,..., Dm cross each other. The subpixel 101 may display one of red, green, and blue colors. In addition, the subpixel 101 may display white color. However, the color displayed by the subpixel 101 is not limited thereto. The subpixel 101 may include a light emitting device and a pixel circuit (not shown) for supplying a driving current to the light emitting device. The light emitting device may be an organic light emitting diode (OLED). The light emitting device may include an anode electrode and an organic light emitting diode including an anode electrode and a cathode electrode through which current flows through the organic layer and the organic layer. The pixel circuit may be connected to a power line or a wire for transmitting a signal.

The pixel circuit may be connected to a gate line transferring a gate signal and a data line transferring a data signal. In addition, the pixel circuit may receive the data signal in response to the gate signal, generate a driving current, and supply the driving current to the organic light emitting diode. In addition, the pixel circuit may be connected to a separate power line (not shown) to receive a driving voltage. However, the wiring connected to the pixel circuit is not limited thereto.

The gate drive circuit 120 may apply a gate signal to the plurality of gate lines G1,..., Gn. The gate drive circuit 120 may sequentially apply gate signals to the plurality of gate lines G1,..., Gn. Here, the gate drive circuit 120 is illustrated as being disposed on one side of the display panel 110, but is not limited thereto. The gate drive circuit 120 may be disposed on both sides of the display panel 110. When the gate drive circuit 120 is disposed on both sides of the display panel 110, one gate drive circuit 120 may be connected to an odd-numbered gate line, and the other gate drive circuit may be connected to an even-numbered gate line.

The data drive circuit 130 may receive an image signal and apply a data signal to the plurality of data lines D1,..., Dm. The video signal may include red, green, and blue data corresponding to red, green, and blue subpixels. In addition, when the subpixel includes a white subpixel, the video signal may include white data. The video signal input to the data drive circuit 130 may be a corrected video signal. The image signal may be a digital signal and the data signal may be a voltage applied to the data lines D1, ..., Dm. Here, the number of data drive circuits 130 is shown as one, but the present invention is not limited thereto, and a plurality of data drive circuits 130 may be implemented in correspondence to the resolution, size, and the like of the display panel 110. The data signal provided by the data drive circuit 130 may be transmitted to a plurality of pixels connected to the gate lines G1,..., Gn receiving the gate signal.

The controller 140 may control the gate drive circuit 120 and the data drive circuit 130. In addition, the controller 140 may supply an image signal to the data drive circuit 130. The controller 140 may receive the corrected image signal and transmit the corrected image signal to the data drive circuit 130. The controller 140 may be a timing controller.

The data processor 150 may receive an input image signal and output a corrected correction image signal to the controller 140. In addition, the input image signal and the correction image signal may include red, green, blue, and data, respectively. In addition, the data processor 150 may divide the display panel 110 into a plurality of regions, set a correction gain for each of the plurality of regions, and correct the input image signal in response to the correction gain to supply the corrected image signal. The plurality of areas divided by the data processor 150 may not be physically divided on the display panel 110 but may be areas allocated by the data processor 150. The data processor 150 may allocate each area to a memory (not shown) and store the correction gain in the allocated area.

Here, the controller 140 and the data processor 150 are illustrated as being distinct from each other, but are not limited thereto. In addition, the gate drive circuit 120, the data drive circuit 130, and the controller 140 may be implemented as integrated circuits, respectively. In addition, the controller 140 may be a timing controller. In addition, the gate drive circuit 120 may be implemented as a gate in panel (GIP) circuit disposed on a substrate on which the display panel 110 is formed and outputting a gate signal.

FIG. 2 is a circuit diagram illustrating an exemplary embodiment of the subpixel illustrated in FIG. 1.

Referring to FIG. 2, the subpixel 101 may include an organic light emitting diode OLED and a pixel circuit 101a.

The organic light emitting diode OLED may emit light by a driving current flowing corresponding to the voltage of the anode electrode and the voltage of the cathode electrode. The anode electrode of the organic light emitting diode OLED may be connected to the second node N2 and the cathode electrode may be connected to the low potential voltage EVSS. In addition, the organic light emitting diode OLED includes an organic film (not shown) and may emit red, green, and blue light corresponding to the organic film. However, it is not limited thereto.

The pixel circuit 101a may transfer a driving current to the organic light emitting diode OLED. The pixel circuit 101a includes the first transistor M1 and the second transistor in the data line DL, the first power line VL1, the second power line VL2, the gate line Gn, and the sensing line Ssen. The M2, the third transistor M3, and the capacitors C may be connected. In addition, the first transistor M1 may be a driving transistor that generates a driving signal corresponding to the data voltage Vdata corresponding to the data signal. In addition, the pixel circuit 101a may include a first switch SAM connecting the second power line VL2 and the ADC 210, and a second switch connecting the second power line VL2 and the reference voltage VREF. (SPRE) may be included.

The first transistor M1 is connected to the first voltage line VL1 through which the first electrode transfers the high potential voltage EVDD, the gate electrode is connected to the first node N1, and the second electrode is connected to the second node (M1). N2). The second node N2 may be connected to the anode electrode of the organic light emitting diode OLED. In addition, the first transistor M1 may allow a driving current to flow from the first electrode to the second electrode in response to the data voltage Vdata transmitted to the first node N1. The magnitude of the driving current may be determined by the voltage difference between the gate electrode and the second electrode. The first electrode may be a drain electrode of the first transistor M1 and the second electrode may be a source electrode. However, it is not limited thereto.

The second transistor M2 has a first electrode connected to a data line DL that transmits a data voltage Vdata, a second electrode connected to a first node N1, and a gate electrode connected to a gate line GL. Can be. The data voltage transmitted through the data line DL may be transmitted to the first node N1 in response to the gate signal transmitted through the gate line GL.

In the third transistor M3, the first electrode may be connected to the second power line VL2, the second electrode may be connected to the second node N2, and the gate electrode may be connected to the sensing line Ssen. The third transistor M3 may transfer the voltage of the second node N2 to the second power line VL2 in response to the sensing signal transmitted through the sensing line Ssen.

The capacitor C is disposed between the first node N1 and the second node N2, and may maintain the voltage of the first node N1 in response to the voltage stored in the capacitor C. The capacitor C may store a voltage corresponding to the data voltage in the first node N1.

In the pixel circuit 101a, the second power line VL2 may be connected to the ADC 210 through the first switch SAM. The ADC 210 may sense the degradation information of the first transistor M1 and / or the organic light emitting diode OLED by receiving the voltage of the second node N2.

Here, the pixel circuit 101a is illustrated as including the first to third transistors M1 to M3 and one capacitor C, but this is by way of example and the pixel circuit 201a is not limited thereto. . The ADC 230 may be included in the data drive circuit 130 of FIG. 1.

3 is a plan view illustrating a display panel divided into a plurality of regions, and FIG. 4 is a graph illustrating a ratio of luminance and current.

Referring to FIG. 3, the display panel 110 may be divided into a plurality of regions 110a. Each region 110a is illustrated as having the same size, but is not limited thereto. One area of the display panel 110 may include a plurality of subpixels. The size and number of the plurality of regions are arbitrary and are not limited thereto. In addition, the data processor 150 illustrated in FIG. 1 may set an address for each area and grasp subpixels included in an area corresponding to each address. The video signals input to the subpixels included in the area may be summed to determine the amount of current flowing in each area.

Referring to FIG. 4, the relationship between the amount of current according to the luminance of red (R), green (G), blue (B), and white (W) emitted from a red subpixel, a green subpixel, a blue subpixel, and a white subpixel Is shown. It can be seen that the color of light emitted from each subpixel increases in amount as the luminance increases. Therefore, it can be seen that the higher the luminance, the more stress the subpixel receives. Since the luminance corresponds to the gray level of the image signal, the amount of current can be checked using the magnitude of the gray level to convert the image signal input to each sub-pixel into a current. In addition, the sum of the currents flowing through the subpixels for each region may be calculated. The calculated amount of current may be accumulated for a predetermined time to check the stress that the subpixel included in the corresponding area will receive. In addition, the accumulated current amount may be used to predict an area in which degradation will occur. In order to suppress the occurrence of deterioration, a correction gain can be set for each region. That is, in the region where the cumulative current amount is high, the correction gain may be set to be large to lower the luminance to limit the flow of current, thereby suppressing the occurrence of degradation. The correction gain can lower the gradation value of the video signal. Here, although light emitted from the subpixels is illustrated as being red, green, blue, and white, the color of light emitted from the subpixels is not limited thereto.

5A to 5C are graphs illustrating a method of setting local gain in the data processor illustrated in FIG. 1.

5A through 5C, the data processor 150 calculates a cumulative current for each area allocated to the display panel 110, and calculates a first current threshold value I. TH_L and a second current threshold value for the accumulated current. I.TH_H) is set. The amount of the cumulative current corresponding to the second current threshold value I. TH_H is set larger than the amount of the accumulated current of the first current threshold value I. TH_L. If the cumulative current of the region is smaller than the first current threshold value I. TH_L, the current gain I. Gain is set to one. When the cumulative current of the region is the second current threshold value I. TH_H, the current gain I. Gain may be set to a value smaller than "1". However, the value of the set current gain I. Gain is not limited thereto. When the cumulative current has a value between the first current threshold value I. TH_L and the second current threshold value I. TH_H, the current gain I. Gain may be set to have a value smaller than one. Here, the slope of the current gain (I. Gain) is to have a predetermined slope.

The first luminance gain L. Gain1 is calculated by applying the current gain I. Gain corresponding to the calculated cumulative current amount to FIG. 5B. The first luminance gain L. Gain1 may correspond to the complexity in the region. When the complexity of the image displayed in the region is high, the luminance decrease due to the I. gain may not be recognized or may be perceived as small. Based on this, if the complexity of the image is high, the luminance change may be set large, and if the complexity of the image is low, the luminance change may be set small. Therefore, the first complexity threshold C.TH_L and the second complexity threshold C.TH_H for the complexity are set. The first complexity threshold C.TH_L corresponds to a smaller complexity than the second complexity threshold C.TH_H. Then, the current gain I. Gain corresponds to the second complexity threshold C.TH_H. For this reason, the first luminance gain L. Gain1 is set to a large value when the complexity is small, and becomes small when the complexity is low. For this reason, as the complexity decreases, the first luminance gain L. Gain1 is set larger, and when the complexity of the image in the region decreases, the first luminance gain L. Gain1 becomes larger.

The second luminance gain L. Gain2 is calculated by applying the current gain I. Gain according to the calculated cumulative current amount to FIG. 5C. The second luminance gain L. Gain2 may correspond to the luminance in the region. As the luminance of the image in the region is lower, the luminance decrease due to the current gain I.Gain is smaller. Based on this, if the luminance of the region is high, the luminance change can be set small. If the luminance of the region is low, the luminance change can be set large. Therefore, the first luminance threshold L. TH_L and the second luminance threshold L. TH_H for luminance are set. The first luminance threshold L. TH_L corresponds to a lower luminance than the second luminance threshold L. TH_H. Then, the current gain I. Gain corresponds to the first luminance threshold L. TH_L. The second luminance gain L. Gain2 has a small value when the luminance of the region is low and a large value when the luminance of the region is high. Therefore, as the luminance is lowered, the second luminance gain L. Gain2 is set smaller, and when the luminance of the image in the area is lower, the second luminance gain L. Gain2 is decreased.

In addition, one of the calculated first luminance gain L. Gain1 and the second luminance gain L. Gain2 may be selected and set as a local gain. Here, the gain having the larger value among the calculated first luminance gain L. Gain1 and the second luminance gain L. Gain2 may be set as a local gain, but is not limited thereto.

6 is a graph illustrating an embodiment of a diffusion coefficient. FIG. 7A illustrates an example of a 3x3 diffusion coefficient, FIG. 7B illustrates an example of local gain set in each region of the display panel, and FIG. 7C illustrates an amount of luminance reduction in each region due to the local gain of FIG. 7B. . 7D shows the luminance reduction amount diffused by the local gain to which the diffusion coefficient is applied. 7E shows correction gains set for each area of the display panel.

Referring to FIG. 6, the diffusion coefficient may have a center having the largest value and a smaller value toward the periphery. The diffusion coefficient can be determined by the function corresponding to the sphere. This allows the difference to be set so that the difference between the coefficients is not large. Since it is set according to the function corresponding to the sphere, the diffusion coefficient can have the largest value at the center and smaller as it moves away from the center. Therefore, the farther from the center, the smaller the magnitude of the coefficient may be.

The diffusion coefficient may be set to have a 3x3 shape as shown in FIG. 7A. However, the magnitude of the diffusion coefficient is not limited thereto. In addition, although the display panel 110 is illustrated as having a 5 × 5 area, the display panel 110 is not limited thereto.

And assuming that local gain as shown in Fig. 7B is set, the luminance reduction due to local gain in each area is shown as shown in Fig. 7C. That is, the luminance reduction amount by the local gain of the first region A is 0.2 and the luminance reduction amount of the second region B is 0.3. When the diffusion coefficient disclosed in FIG. 7A is applied to the luminance reduction amount shown in FIG. 7C, the luminance reduction amount as shown in FIG. 7D can be calculated.

Referring to FIG. 7D, the first region A has a luminance reduction amount of 0.2 and the second region B has a luminance reduction amount of 0.3. That is, the first area A and the second area B have the same amount of brightness reduction as before the diffusion coefficient is applied. However, the peripheral area of the first area A and the second area B is affected by the luminance reduction amounts 0.2 and 0.3, resulting in luminance reduction. Therefore, the difference between the luminance reduction amount of the first region A and the second region B and that of the peripheral region is reduced. By converting this, each region may calculate a correction gain as shown in FIG. 7E. Therefore, the correction gain may be a gain obtained by diffusing the local gain using a diffusion coefficient. In addition, since the correction gain is obtained by using the diffusion coefficient, the correction gain may be diffused around while the local gain itself is kept small.

8 is a graph illustrating peak luminance set in the data processor illustrated in FIG. 1.

Referring to FIG. 8, if the cumulative current amount of the current flowing in the display panel 110 is greater than or equal to a threshold, the data processor 150 may adjust the peak luminance corresponding to the first peak luminance curve Peak1 or the second peak luminance curve Peak2. You can choose.

Average picture level (APL) corresponds to a luminance average value of subpixels for each frame of an image displayed on the display panel 110 and may be displayed as a percentage. The APL may correspond to the gray value of the video signal. The data processor 150 may calculate an APL by summing video signals input in one frame. When the maximum gray level is 255, 255, 255 When the gray level of the image input to the red, green, and blue subpixels is 255, 255, 255, the image displayed on the display panel 110 may be displayed in white. The data processor 150 may calculate that the APL is 100%. When the gray level of the image displayed on the display panel 110 is gradually lowered, the APL calculated by the data processor 150 becomes smaller.

Here, the first peak luminance curve Peak1 sets the peak luminance of the subpixel to 150 nits when the APL is 100%, and sets the peak luminance of the subpixel to 500 nits when the APL is 25%. Even if the APL becomes smaller than 25%, the peak luminance of the subpixel may not be set to exceed 500 nits. However, it is not limited thereto.

If the APL is 100%, the image displayed on the display panel 110 is all white, so that an image having high luminance is displayed. In this case, when the peak luminance is lowered, visibility may be increased and power consumption may be lowered. Therefore, the peak luminance is limited to 150 nits when the APL is 100%.

When the APL is 25%, the image displayed on the display panel 110 is a dark image. Increasing the peak luminance increases the contrast difference between the dark and the bright parts in the image, making the image more clear. Therefore, as the APL decreases, the peak luminance gradually increases.

In addition, the second peak luminance curve Peak2 is set to a maximum luminance of the subpixel lower than 150 nits when the APL is 100%, and the maximum luminance of the subpixel is lower than 500 nits when the APL is 25%. When the APL is smaller than 25%, the maximum luminance of the subpixels can be prevented from exceeding a value lower than the set 500 nits.

If the risk of deterioration is not high, it may correspond to the first peak luminance curve Peak1, but if the risk of deterioration is high, the response may correspond to the second peak luminance curve Peak2. When the display panel 110 displays an image corresponding to the second peak luminance curve Peak2, less current flows than the case where the image is displayed in response to the first peak luminance curve Peak1, thereby suppressing deterioration. can do. If a threshold value of the accumulated current with respect to the current flowing through the display panel 110 is set for a predetermined time and higher than the threshold value, it may be determined that there is a high possibility of deterioration.

9 is a structural diagram illustrating a first embodiment of the data processing unit shown in FIG. 1.

Referring to FIG. 9, the data processor 150 may include a first operator 151a that calculates a cumulative current amount for each area, and a second gain that calculates correction gains for each area corresponding to the cumulative current amount calculated by the first operator 151a. The calculation unit 152a may be included. In addition, the second operation unit 152a includes a current gain corresponding to the accumulated current amount of the region, a first luminance gain of the region corresponding to the complexity and current gain of the region, and a second of the region corresponding to the luminance and current gain of the region. The luminance gain may be calculated, and local gain corresponding to the area may be set by selecting one of the first luminance gain and the second luminance gain. In addition, the second operator 152a may set a correction gain corresponding to the set local gain. In addition, the second operation unit 152a may calculate a correction gain by applying a diffusion coefficient to the local gain.

In addition, the data processor 150 may set an APL calculator 153a for calculating an APL by summing up the input video signal or the corrected video signal for each frame, and set a peak luminance corresponding to the APL calculated by the APL calculator 153a. have. The APL gain calculator 154a may further include an APL gain operator 154a for adjusting the APL gain in response to the set peak luminance.

The APL calculator 153a may receive an input video signal and calculate an APL. The APL calculator 153 may calculate an APL by summing input video signals input for each frame. Here, the APL calculator 153a receives the input image signal and calculates the APL. However, the APL calculator 153a is not limited thereto, and the APL calculator 153a may receive the corrected image signal corrected by the correction gain to calculate the APL.

The APL gain operator 154a may calculate the APL gain. By selecting the gray scale voltage according to the APL gain, the first peak luminance curve Peak1 or the second peak luminance curve Peak2 illustrated in FIG. 8 can be selected. If the accumulated current amount accumulated for a predetermined time does not exceed the threshold, the APL gain operator 154a selects APL gain as “1” to correspond to the first peak luminance curve Peak1 and accumulates the accumulated current amount for the predetermined time. When this threshold is exceeded, the APL gain may be selected to be smaller than "1" to correspond to the second peak luminance curve Peak2.

The selection of the first peak brightness curve Peak1 or the second peak brightness curve Peak2 may be achieved by adjusting the voltage of the data signal. If the APL of the image displayed on the display panel 110 is high, the voltage of the data signal input to the subpixels is set low, thereby lowering the overall luminance of the display panel 110 and reducing the APL of the image displayed on the display panel 110. When low, the overall brightness of the display panel 110 may be increased by setting a high voltage of the data signal input to the sieve pixels.

FIG. 10 is a structural diagram illustrating a second embodiment of the data processing unit shown in FIG. 1.

Referring to FIG. 10, the data processor 150 may include a first operator 151b that calculates a cumulative current amount for each area, and a second gain that calculates correction gains for each area corresponding to the cumulative current amount calculated by the first operator 151b. The calculation unit 152b may be included. Further, the second operation unit 152b includes a current gain corresponding to the accumulated current amount of the region, a first luminance gain of the region corresponding to the complexity and current gain of the region, and a second of the region corresponding to the luminance and current gain of the region. The luminance gain may be calculated, and local gain corresponding to the area may be set by selecting one of the first luminance gain and the second luminance gain. In addition, the second operator 152b may set a correction gain corresponding to the set local gain. In addition, the second operation unit 152b may calculate a correction gain by applying a diffusion coefficient to the local gain.

In addition, the data processor 150 may include an APL calculator 153b for calculating an APL by summing up the input image signal or the corrected image signal for each frame, and PWM (Pulse) for controlling the emission time of the subpixel in response to the set peak luminance. Width Modulation) may further include a control unit 154b.

The APL calculator 153b may receive an input video signal and calculate an APL. Here, although the APL calculator 153 receives the input image signal and calculates the APL, the present invention is not limited thereto, and the APL calculator 153 may receive the corrected image signal corrected by the correction gain to calculate the APL.

The PWM controller 154b may control the pulse widths of the data signals Vdata1 and Vdata2 as illustrated in FIGS. 11A and 11B. That is, when the APL calculated by the APL calculating section 153b is large, as shown in FIG. 11A, the pulse width Wd1 of the data signal Vdata1 is set short, and when the calculated APL is small, as shown in FIG. 11B. The pulse width Wd2 of the data signal Vdata2 may be set long. Therefore, when the APL of the image displayed on the display panel 110 is high, the time for which the subpixels emit light is shortened, thereby lowering the overall luminance of the display panel 110 and lowering the APL of the image displayed on the display panel 110. In this case, the luminance of the display panel 110 may be increased by setting a length of time that the sieve pixels emit light. That is, as the APL value decreases, the peak luminance increases, so that the luminance difference between the subpixels expressing low gray levels and the subpixels expressing bright colors increases in a frame, thereby increasing contrast. Therefore, the dynamic range of the display panel 110 can be improved by changing the peak luminance corresponding to the APL.

In addition, the PWM controller 154 may set the peak luminance at the first peak luminance curve Peak1 when the accumulated current flowing in the display panel 110 for a predetermined time in at least one region of the plurality of regions for a predetermined period is greater than or equal to a threshold. The second peak luminance curve Peak2 may be changed to correspond to the second peak luminance curve Peak2 lower than the first peak luminance curve Peak1. The cumulative current amount accumulates the current flowing in the display panel 110 for a preset time, and the PWM controller 154b may be transmitted from the first operator 151b. However, it is not limited thereto.

The global gain may be set according to the peak luminance curves Peak1 and Peak2 and the correction gain may be calculated based on the set global gains so as to select the first or second peak luminance curve Peak2. Computing the global gain to the correction gain may be performed by the second calculator 152. However, it is not limited thereto. The global gain may be set to a value of "1" if it is determined that the accumulated current accumulated for a predetermined time is less than or equal to the threshold, and less than "1" if it is determined that the accumulated current is greater than or equal to the threshold. However, it is not limited thereto. If the accumulated current amount is less than or equal to the threshold for a predetermined time, the global gain is set to "1" to select the first peak luminance curve Peak1.

12 is a timing diagram illustrating a process of changing from a first peak luminance to a second peak luminance.

Referring to FIG. 12, when the accumulated current amount is greater than or equal to the threshold value for a predetermined time, the global gain may be set to a value smaller than "1" and may be changed from the first peak luminance curve Peak1 to the second peak luminance curve Peak2. When the first peak luminance curve Peak1 is changed from the second peak luminance curve Peak2, an image is displayed in response to the first peak luminance curve Peak1 in one frame, and the second peak luminance curve An image may be displayed in response to the peak2). In this case, when two frames display the same image or a similar image, a luminance difference is generated between one frame and the next frame so that the user may recognize that the display panel 110 becomes dark. Recognizing that it is dark can be determined to be bad. In order to solve this problem, the display panel 110 may not be perceived to be dark by gradually changing the global gain value so that the luminance difference between the frames is not large.

If it is determined by the data processor 150 that the accumulated current is greater than or equal to the threshold, the global gain does not change during the first period Td1. After the first period Td1 has elapsed, the global gain may be decreased to gradually reduce the global gain during the second period Td2. In this case, it may take time for the plurality of frames to be displayed on the display panel 110 in the second period Td2. When the global gain decreases, the peak luminance may correspond to the second peak luminance curve Peak2.

The third period Td2 is maintained while the magnitude of the cumulative current is greater than or equal to the threshold value so that the image displayed on the display panel 110 may correspond to the second peak luminance curve Peak2. When the amount of current accumulated for a predetermined period is less than or equal to the threshold, the global gain is set to "1" so as to enter the fourth period Td4 so that the peak luminance becomes the first peak luminance curve Peak1 in the second peak luminance curve Peak2. Set to "." Since the display device according to the present invention is for predicting deterioration occurrence and suppressing deterioration occurrence by using the accumulated cumulative current amount, deterioration does not actually occur even if the accumulated current amount is more than a threshold value. Therefore, when the amount of current accumulated over a certain period again becomes below the threshold value, the global gain becomes “1” so that the peak luminance corresponds to the first peak luminance curve Peak1 so that an image may be displayed.

13 is a flowchart illustrating an embodiment of a method of driving a display device according to the present invention.

Referring to FIG. 13, the driving method of the display device 100 may calculate the cumulative current amount for each of the plurality of areas of the display panel 110. (S120) The plurality of areas are physically divided on the display panel 110. It may be an area allocated to the address by the data processing unit 150. Also, a plurality of subpixels may be included in one region. In addition, when calculating the cumulative current amount, the grayscale values corresponding to the input image signal input at a predetermined time may be summed, and the current values set to the respective grayscale values may be summed and calculated.

The correction gain may be set for each region corresponding to the accumulated current amount. (S121) When setting the correction gain, the cumulative current amount is set using the current value set in the gradation value corresponding to the input video signal. By using the coefficient, the size difference of the correction gains can be set small. When setting the correction gain, the current gain corresponding to the accumulated current amount accumulated for each region, the first luminance gain corresponding to the complexity of the region corresponding to the current gain, and the second luminance corresponding to the luminance of the region corresponding to the current gain The gain may be calculated, and one of the first luminance gain and the second luminance gain may be selected and output to correspond to the correction gain. When the brightness of the image displayed on the display panel 110 is reduced in at least one area, if the complexity is high in the area, it may not be recognized or less recognized that the brightness is reduced. Therefore, when the complexity is low, the first luminance gain is set to have a large value so that the luminance decrease is set to a small value. When the complexity is high, the first luminance gain is set to have a small value to increase the amount of the luminance decrease. Can be set. In addition, when the brightness of the image displayed on the display panel 110 is reduced in at least one area, the brightness may be recognized when the brightness is high before the brightness is lowered in the area, and when the brightness is low, the brightness may not be recognized. Can be perceived less or less. Therefore, when the luminance is high, the second luminance gain may be set to have a high value, and when the luminance is low, the second luminance gain may be set to have a low value. Then, one of the first luminance gain and the second luminance gain may be selected to be a correction gain. The correction gain may include a luminance gain having a larger value among the first luminance gain and the second luminance gain. The video signal may be corrected by the correction gain to change the amount of current flowing in each region.

In addition, a corrected video signal obtained by correcting an input video signal in response to the corrected gain may be generated, and the display panel 110 may be driven in response to the corrected video signal. The luminance of the region can be lowered, so that deterioration can be suppressed. In addition, when the image is displayed, the emission time of the display panel may be controlled in one frame section in response to an APL obtained by adding the input image signal or the correction image signal input for each frame. As a result, the luminance difference between the subpixels emitting with high gradation and the subpixels emitting with low gradation may increase, resulting in increased contrast. In addition, if the cumulative current amount is less than or equal to the threshold value in at least one of the plurality of areas for a predetermined time, the first global gain is calculated in the input image signal or the corrected image signal. The second global gain having the value may be calculated on the input image signal or the correction image signal.

The above description and the accompanying drawings are merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may combine the configurations within a range not departing from the essential characteristics of the present invention. Various modifications and variations may be made, including separation, substitution, and alteration. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: display device
110: display panel
120: gate drive circuit
130: data drive circuit
140: control unit
150: data processing unit

Claims (16)

A display panel intersecting a gate line and a data line and including a plurality of pixels connected to the gate line and the data line;
A data processor for dividing the display panel into a plurality of regions, setting a correction gain for each of the plurality of regions, and correcting an input image signal corresponding to the correction gain to supply a corrected image signal;
A gate drive circuit for applying a gate signal to the gate line;
A data drive circuit for applying the data signal to the data line in response to the corrected image signal; And
And a controller which controls the gate drive circuit and the data drive circuit and receives the corrected image signal from the data processor and supplies the corrected image signal to the data drive circuit.
The method of claim 1,
And the correction gain is set corresponding to a cumulative amount of current accumulated for each region during a preset period.
The method of claim 2,
The data processing unit includes a first operation unit for calculating the accumulated current amount for each area, and a second operation unit for calculating the correction gain for each area corresponding to the accumulated current amount calculated in the first operation unit. .
The method of claim 3,
The second operation section includes a current gain corresponding to the accumulated current amount of the region, a first luminance gain of the region corresponding to the complexity and the current gain of the region, and a luminance and the current gain of the region. Calculating a second luminance gain of the region, selecting one of the first luminance gain and the second luminance gain to set a local gain corresponding to the region, and setting the correction gain corresponding to the local gain Light emitting display device.
The method of claim 1,
The data processor may include a current gain corresponding to the accumulated current amount accumulated for each of the regions, a first luminance gain corresponding to the complexity of the region corresponding to the current gain, and a luminance of the region corresponding to the current gain. An organic light emission for calculating a second luminance gain, selecting one of the first luminance gain and the second luminance gain to set a local gain corresponding to the region, and setting the correction gain corresponding to the local gain Display.
The method of claim 5,
And the correction gain is calculated by applying a diffusion coefficient to the local gain.
The method of claim 5,
The plurality of areas includes a first area having a first local gain set and a second area neighboring the first area and having a value greater than the first local gain set, wherein the correction gain is a value of the second local gain. The organic light emitting display device as claimed in claim 1, wherein the organic light emitting display device is configured to set a correction gain correcting a difference between the first local gain and the second local gain.
The method of claim 1,
The data processor is configured to calculate an APL by summing the input video signal or the corrected video signal for each frame, and a peak luminance corresponding to the APL calculated by the APL calculator is set. And a PWM control unit for controlling the emission time of the display panel in one frame period.
The method of claim 1,
The data processor is configured to calculate an APL by summing the input video signal or the corrected video signal for each frame, and a peak luminance corresponding to the APL calculated by the APL calculator is set. And a PWM control unit for controlling the emission time of the display panel in one frame period.
The method of claim 1,
If the cumulative current flowing in the display panel in at least one of the plurality of areas is greater than or equal to a threshold value for a predetermined period, the data processing unit may set the peak luminance to a second peak luminance lower than the first peak luminance from the first peak luminance. The organic light emitting diode display of claim 1, wherein the organic light emitting display device is gradually reduced from the first peak luminance to the second peak luminance for a predetermined reduction period.
Calculating a cumulative current amount for each of a plurality of regions of the display panel;
Setting a correction gain for each region in correspondence with the accumulated current amount; And
And generating a corrected video signal by correcting an input video signal in response to the correction gain, and driving the display panel in response to the corrected video signal.
The method of claim 11,
And setting the correction gain to set a small difference between the correction gains using a diffusion coefficient.
The method of claim 11,
The calculating of the cumulative current amount may include adding a gray value corresponding to an input image signal input at a predetermined time and adding the current value to each gray value to calculate the cumulative current amount. .
The method of claim 11,
The setting of the correction gain may include: a current gain corresponding to the cumulative current amount of the region, a first luminance gain of the region corresponding to the complexity and the current gain of the region, a luminance and the current gain of the region; Calculating a second luminance gain of the corresponding region, selecting one of the first luminance gain and the second luminance gain to set a local gain corresponding to the region, and setting the correction gain corresponding to the local gain A method of driving an organic light emitting display device.
The method of claim 10,
And displaying the image by controlling the light emission time of the display panel in one frame section in response to an APL obtained by adding the input image signal or the corrected image signal input for each frame.
The method of claim 14,
The first global gain is calculated on the input image signal or the corrected image signal when the cumulative current amount is less than or equal to a threshold value in at least one of the plurality of areas for a predetermined time. And a second global gain having a low value calculated on the input image signal or the corrected image signal.

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