KR102113613B1 - Organic Light Emitting Display Device and Driving Method the same - Google Patents

Abstract

The present invention is a cognitive gain control unit for adjusting the gain of the RGB data signal so that the color is controlled based on the color difference (ΔEab) reflecting the human cognitive characteristics; A data control unit for converting the RGB data signal to an RGBW data signal and compensating for the RGBW data signal; And it provides an organic light emitting display device including a display panel for displaying an image based on the RGBW data signal.

Description

Organic light emitting display device and driving method thereof {Organic Light Emitting Display Device and Driving Method the same}

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

An organic light emitting device used in an organic light emitting display device is a self-light emitting device in which a light emitting layer is formed between two electrodes. In the organic electroluminescent device, electrons and holes are injected into the emission layer from electron injection electrodes (cathode) and hole injection electrodes (anode), respectively, and excitons in which the injected electrons and holes are combined are excited. It is a device that emits light when it falls from the ground to the ground state.

In the organic light emitting display device, when a scan signal, a data signal, and a power supply are supplied to sub-pixels arranged in a matrix form, a transistor included in the selected sub-pixel is driven. In addition, the organic light emitting diode emits light corresponding to the current formed at this time, thereby displaying an image.

Some of the organic light emitting display devices have an organic light emitting display device (hereinafter abbreviated as RGBW OLED) having a sub-pixel structure including red, green, blue and white in order to prevent luminance deterioration and color deterioration while increasing light efficiency. ).

In RGBW OLED, the RGB sub-pixel uses a color filter, while the W sub-pixel does not use a color filter. For example, assuming that the transmittance of the color filter is 50%, the W sub-pixel has at least twice the efficiency of the RGB sub-pixel.

The RGBW OLED has an advantage in that power consumption can be lowered according to the use ratio of the W sub-pixel because the light emission efficiency of the W sub-pixel is higher than that of the RGB sub-pixel. The RGBW OLED proposed in the related art determines the use ratio of the W sub-pixel with a fixed value experimented on the basis of a specific evaluation image and reflects this to control power consumption. For example, the high gradation of the RGB sub-pixels is reduced to an experimental value to reduce the usage of the RGB sub-pixels, and the lowered luminance is compensated through the W sub-pixels.

However, the conventionally proposed method calculates the usage of the W sub-pixel through the subjective evaluation of the experimenter, so the W sub-pixel is excessively used due to the parameter calculation error, resulting in deterioration in image quality or insufficient use of the W sub-pixel, thereby reducing power consumption. There is a problem that is ineffective.

The present invention for solving the above-described problems of the background technology is to reduce the power consumption by controlling the color to minimize the perception of color change. In addition, the present invention is to reduce power consumption by adjusting the amount of light (or usage) of a sub-pixel in response to characteristics of an image, such as whether it is a still image or a moving image, complexity of an image, and degree of chromaticity of an image.

The present invention as a solution to the above-described problems is a cognitive gain control unit for adjusting the gain of the RGB data signal so that the color is controlled based on the color difference (ΔEab) reflecting the cognitive characteristics of the person; A data control unit for converting the RGB data signal to an RGBW data signal and compensating for the RGBW data signal; And it provides an organic light emitting display device including a display panel for displaying an image based on the RGBW data signal.

The cognitive gain control unit varies the gain control of the RGB data signal between the still image and the video by reflecting the cognitive characteristics of the person, but in the case of a video, the gain of the RGB data signal can be differentially increased or decreased according to movement.

The cognitive gain control unit calculates the chromaticity (or saturation) for the RGB data signal, calculates the gain for chromaticity, calculates the color difference for the RGB data signal, calculates the color difference gain, and calculates the RGB data signal. In addition to calculating the motion value to determine whether is a moving picture or a still image, the gain for the motion value is calculated, and the cognitive gain control unit synthesizes the gain for chromaticity, color difference, and motion value to gain the RGB data signal. Can be adjusted.

The cognitive gain control unit calculates the edge to determine the degree of complexity of the RGB data signal, and calculates the gain for the edge. The cognitive gain control unit controls the chromaticity, color difference, edge, and motion values. The gain of the RGB data signal can be adjusted by synthesizing the gains.

The cognitive gain control unit calculates the chromaticity (or saturation) for the RGB data signal, as well as the first parameter calculation unit for calculating the gain for the chromaticity, and the chromaticity difference for the RGB data signal, and the gain for the color difference. A second parameter calculation unit for calculating, a third parameter calculation unit for calculating a motion value for determining whether the RGB data signal is a moving picture or a still image, and a gain for a motion value, and an RGB data signal In addition to calculating an edge to determine the degree of complexity, a fourth parameter calculating unit may calculate a gain for the edge.

The cognitive gain control unit may include a power consumption reduction gain calculation unit that adjusts the gain of the RGB data signal as a result of summing the gains obtained from at least one of the first to fourth parameter calculation units.

The cognitive gain control unit gains the RGB data signal so that the emission amount (or usage amount) of the sub-pixels included in the display panel is varied according to whether it is a still image or a video, the complexity of the image and the chromaticity (or saturation degree) of the image. Can be adjusted.

The first parameter calculator may calculate a maximum value and a minimum value among RGB data signals, and calculate chromaticity as a difference value obtained by subtracting the minimum value from the maximum value.

The second parameter calculator may calculate the color difference by calculating chromaticity coefficient values, red coefficient values, green coefficient values, blue coefficient values, and constant values through regression analysis.

In another aspect, the present invention includes calculating a chroma (or saturation) for an RGB data signal and calculating a gain for the chroma; Calculating a color difference for the RGB data signal and calculating a gain for the color difference; Calculating a motion value for determining whether the RGB data signal is a video or a still image, and calculating a gain for the motion value; Calculating an edge and calculating a gain for the edge to determine the degree of complexity of the RGB data signal; And adjusting the gain of the RGB data signal with a result of combining at least one of a gain for chromaticity, a gain for chrominance, a gain for motion value, and a gain for edge. Gives

In the step of calculating the gain for the chromaticity, the maximum and minimum values of the RGB data signals may be calculated, and the chromaticity may be calculated as a difference value obtained by subtracting the minimum value from the maximum value.

The step of calculating the gain for the color difference may calculate the color difference by calculating chromaticity coefficient values, red coefficient values, green coefficient values, blue coefficient values, and constant values through regression analysis.

The present invention has the effect of reducing power consumption by controlling the color so that the perception of color change is minimized in an organic light emitting display device (hereinafter abbreviated as RGBW OLED) having a sub-pixel structure including red, green, blue, and white. have. In addition, the present invention has an effect of reducing power consumption by adjusting the amount of light (or usage) of sub-pixels in response to characteristics of an image such as whether it is a still image or a moving image, complexity of an image, and degree of chromaticity of an image.

1 is a schematic configuration diagram of an organic light emitting display device according to an embodiment of the present invention.
2 is a modified example of the cognitive gain control unit and the data control unit.
3 is an exemplary circuit configuration of a sub-pixel.
4 is a schematic cross-sectional hierarchical diagram of a sub-pixel.
5 is an example of various arrangements of sub-pixels.
6 is a view for explaining the concept of compensated light emission of a sub-pixel.
7 is a configuration diagram showing a partial configuration of an organic light emitting display device according to an embodiment of the present invention.
8 is a block diagram showing the cognitive gain control unit of FIG. 7.
9 is a block diagram showing the data control unit of FIG. 7;
10 is a graph showing the relationship between power consumption and movement according to gain control of the cognitive gain control unit.
11 is a graph showing the relationship between power consumption and movement when the cognitive gain control unit differentially increases or decreases according to movement when adjusting the gain.
12 to 14 are views showing a light emission form of the RGBW sub-pixel according to the gain control of the cognitive gain control unit.
15 is a flowchart illustrating a method of driving an organic light emitting display device according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, specific details for the practice of the present invention will be described.

1 is a schematic configuration diagram of an organic light emitting display device according to an exemplary embodiment of the present invention, FIG. 2 is a modified example diagram of a cognitive gain control unit and a data control unit, and FIG. 3 is an exemplary circuit configuration of a sub-pixel. , FIG. 4 is a schematic cross-sectional hierarchical diagram of sub-pixels, FIG. 5 is a diagram illustrating various arrangements of sub-pixels, and FIG. 6 is a view for explaining the concept of compensation light emission of a sub-pixel.

1, the organic light emitting display device according to an embodiment of the present invention includes an image processing unit 110, a cognitive gain control unit 120, a data control unit 130, a timing control unit 140, data The driving unit 150, the gate driving unit 160 and the display panel 170 are included.

The image processing unit 110 outputs a data enable signal DE in addition to the RGB data signal RGB supplied from the outside. The image processing unit 110 may output one or more of a vertical synchronization signal, a horizontal synchronization signal, and a clock signal in addition to the data enable signal DE, but these signals are omitted for convenience of description.

The cognitive gain control unit 120 and the data control unit 130 are composed of separate logic blocks or as shown in the image processing unit 110 or FIG. 2 (b) as shown in FIG. 2 (a). Likewise, it is included in the timing control unit 140. The description of the cognitive gain control unit 120 and the data control unit 130 will be described below.

The timing control unit 140 receives the RGBW data signal RGBW from the data control unit 130. The timing control unit 140 receives a driving signal including a data enable signal DE, a vertical synchronization signal, a horizontal synchronization signal, and a clock signal in addition to the RGBW data signal RGBW from the data adjustment unit 130. The driving signal including the data enable signal DE, the vertical synchronization signal, the horizontal synchronization signal, and the clock signal may be output from the image processing unit 110 rather than the data adjustment unit 130.

The timing control unit 140 is a gate timing control signal GDC for controlling the operation timing of the gate driver 160 based on the driving signal and a data timing control signal DDC for controlling the operation timing of the data driver 150. Output The timing controller 140 outputs an RGBW data signal RGBW in response to the gate timing control signal GDC and the data timing control signal DDC generated based on the driving signal.

The data driving unit 150 samples and latches the RGBW data signal RGBW supplied from the timing control unit 140 in response to the data timing control signal DDC supplied from the timing control unit 140, converts it to a gamma reference voltage, and outputs it. do. The data driver 150 outputs an RGBW data signal RGBW through the data lines DL1 to DLn. The data driver 150 is formed in the form of an integrated circuit (IC).

The gate driver 160 outputs a gate signal while shifting the level of the gate voltage in response to the gate timing control signal GDC supplied from the timing controller 140. The gate driver 160 outputs a gate signal through the gate lines GL1 to GLm. The gate driver 160 is formed in the form of an integrated circuit (IC) or a gate-in-panel method on the display panel 170.

The display panel 170 increases red light efficiency, and prevents red color sub-pixels SPr, green sub-pixels SPg, blue sub-pixels SPb, and white sub-pixels SPw (hereinafter referred to as "brightness") and prevents color deterioration. RGBW sub-pixels). That is, one pixel is composed of RGBW sub-pixels (SPr, SPg, SPb, SPw).

As illustrated in FIG. 3, one sub-pixel includes a switching transistor SW, a driving transistor DR, a capacitor Cst, a compensation circuit CC, and an organic light emitting diode OLED. The organic light emitting diode OLED operates to emit light according to the driving current formed by the driving transistor DR. The switching transistor SW operates to switch the data signal supplied through the first data line DL1 to be stored as a data voltage in the capacitor Cst in response to the gate signal supplied through the first gate line GL1. The driving transistor DR operates to flow driving current between the first power supply line VDD and the ground line GND according to the data voltage stored in the capacitor Cst. The compensation circuit CC compensates for the threshold voltage of the driving transistor DR. The compensation circuit CC is composed of one or more transistors and capacitors. The configuration of the compensation circuit CC is very diverse, so detailed examples and descriptions thereof are omitted.

One sub-pixel is composed of a 2T (Transistor) 1C (Capacitor) structure including a switching transistor SW, a driving transistor DR, a capacitor Cst, and an organic light emitting diode OLED. However, when the compensation circuit CC is added, it is composed of 3T1C, 4T2C, and 5T2C. The sub-pixel having the above structure is formed in a top-emission method, a bottom-emission method or a dual-emission method depending on the structure.

Meanwhile, the RGBW sub-pixels SPr, SPg, SPb, and SPw are implemented by using a white organic light emitting diode (WOLED) and RGB color filters (CFr, CFg, CFb). The method of using a white organic light emitting diode (WOLED) and RGB color filters (CFr, CFg, CFb) is as follows.

As illustrated in FIG. 4, the RGBW sub-pixels SPr, SPg, SPb, and SPw include a transistor unit TFT, RGB color filters CFr, CFg, CFb, and a white organic light emitting diode (WOLED). On the other hand, the white sub-pixel SPw includes a transistor portion TFT and a white organic light emitting diode (WOLED). The RGB sub-pixels SPr, SPg, and SPb convert white light emitted from the white organic light emitting diode WOLED into red, green, and blue, and thus include RGB color filters CFr, CFg, and CFb. Unlike this, the white sub-pixel SPw emits white light emitted from the white organic light emitting diode WOLED as it is, and thus a color filter is not included.

The method using RGBW sub-pixels (SPr, SPg, SPb, SPw) deposits a white light-emitting material on all sub-pixels, unlike the method in which red, green and blue light-emitting materials are deposited on each sub-pixel independently. For this reason, this method can be enlarged without using a fine metal mask. In addition, assuming that the transmittance of the color filter is 50%, the W sub-pixels have at least twice the efficiency of the RGB sub-pixels, and thus the lifespan can be extended and the power consumption can be lowered according to the use ratio of the W sub-pixels.

The display panel 170 may variously arrange sub-pixels to improve color purity or expressive power, as well as to match a target color coordinate. For example, the display panel 170 may have a structure arranged in the order of RGBW sub-pixels SPr, SPg, SPb, and SPw as shown in FIG. 5A. In addition, the display panel 170 may have a structure arranged in the order of WRGB sub-pixels SPw, SPr, SPg, and SPb, as shown in FIG. 5B. In addition, the display panel 170 may have a structure arranged in the order of WGBR sub-pixels SPw, SPg, SPb, and SPr as shown in FIG. 5C. In addition, the display panel 170 may have a structure arranged in the order of the RWGB sub-pixels SPr, SPw, SPg, and SPb as shown in FIG. 5D. In addition, the display panel 170 may have a structure arranged in the order of BGWR sub-pixels SPb, SPg, SPw, and SPr as shown in FIG. 5E. The display panel 170 may have sub-pixel structures arranged in various orders in addition to the examples shown and described above.

The organic light emitting display device described above uses RGBW sub-pixels (SPr, SPg, SPb, and SPw) to display desired color coordinates on the display panel 170, as well as W sub-pixels (SPw) and RGB sub-pixels (SPr, SPg) , SPb) is partially or fully compensated. For example, as shown in FIG. 6 (a), the RG sub-pixels SPr and SPg are compensated for light emission so that a desired white color coordinate (White) is expressed on the display panel 170. As another example, the GB sub-pixels SPg and SPb are compensated for light emission as well as the W sub-pixel SPw as shown in FIG. 6B so that a desired white color coordinate (White) is expressed on the display panel 170.

Hereinafter, descriptions of these organic light emitting display devices according to some embodiments of the present invention will be described.

FIG. 7 is a block diagram showing a part of the organic light emitting display device according to an embodiment of the present invention, FIG. 8 is a block diagram showing the cognitive gain control unit of FIG. 7, and FIG. 9 is a data control unit of FIG. 7 It is a block diagram.

As shown in FIG. 7, the organic light emitting display device according to the exemplary embodiment of the present invention includes a cognitive gain control unit 120, a data control unit 130, an optical compensation memory unit 135, and a timing control unit 140. ), A data driving unit 150 and a gamma unit 155 are included. The cognitive gain control unit 120, the data control unit 130, the optical compensation memory unit 135, the timing control unit 140, the data driving unit 150, and the gamma unit 155 will be described schematically as follows. same.

The cognitive gain control unit 120 adjusts and outputs the gain of the RGB data signal RGB supplied from the image processing unit. The cognitive gain control unit 120 controls the color based on the color difference (ΔEab) reflecting the cognitive characteristics of the person when adjusting the gain of the RGB data signal RGB to lower the power consumption of the display panel. At this time, the cognitive gain control unit 120 varies the gain control of the data signal RGB between the still image and the video by reflecting the cognitive characteristics of the person, but in the case of a video, the gain of the data signal RGB is different according to the movement Increases or decreases.

The data control unit 130 converts the RGB data signal RGB supplied from the cognitive gain control unit 120 into an RGBW data signal RGBW and outputs the converted RGB data signal RGBW. The data control unit 130 converts the RGB data signal RGB into an RGBW data signal RGBW, and calculates and compensates the actual light emission ratio of the converted RGBW data signal RGBW and the amount of light emission of the sub-pixel to compensate. do.

For example, the data control unit 130 uses RGBW sub-pixels SPr, SPg, SPb, and SPw to display the desired color coordinates on the display panel, and W sub-pixels SPw and RGB sub-pixels SPr, SPg, SPb. Compensate light emission of some or all of them. On the other hand, in the case of the RGB data signal (RGB) supplied from the cognitive gain control unit 120, since the gain is adjusted, the data control unit 130 compensates with reference to this when converting data.

The data adjusting unit 130 refers to a RGB data signal (RGB) and a lookup table stored in the optical compensation memory unit 135 as well as data conversion and compensation, and a luminance control signal (PLCS) for controlling luminance by at least one frame. Produces and prints

The timing control unit 140 outputs an RGBW data signal RGBW corresponding to the gate timing control signal GDC and the data timing control signal DDC generated based on the driving signal supplied from the image processing unit or the data adjustment unit. .

The gamma unit 155 outputs a gamma voltage GMAV capable of changing gamma in response to the luminance control signal PLCS supplied from the data adjusting unit 130. The gamma unit 155 may use a programmable gamma unit that can increase design freedom, but is not limited thereto.

The data driving unit 150 converts the RGBW data signal RGBW supplied from the timing control unit 140 to the gamma voltage GMAV supplied from the gamma unit 155 and converts the digital system data signal into an analog system and displays the panel. Output to The data driver 150 converts the RGBW data signal RGBW in response to the gamma voltage GMAV supplied from the gamma unit 155. Therefore, the luminance is adjusted in response to the luminance control signal PLCS supplied from the data adjusting unit 130.

As illustrated in FIG. 8, the cognitive gain control unit 120 includes a chroma calculation unit 120a and Chroma Cal, a color difference calculation unit 120b and ΔEab Cal, and a motion calculation unit 120c and Motion Cal. Data converter (120d, RGB TO Y), chroma gain calculator (120e, Chroma Gain), color difference gain calculator (120f, △ Eab Gain), motion gain calculator (120g, Motion Gain), edge calculator (120h) , Edge Cal), power consumption reduction gain calculation unit 120i (CPR Gain), and edge gain calculation unit 120j (Edge Gain).

The chroma calculation unit 120a calculates chroma (or saturation) for the RGB data signal RGB supplied from the image processing unit. The chroma calculation unit 120a calculates a maximum value and a minimum value among the RGB data signals RGB and calculates chromaticity as a difference value obtained by subtracting the minimum value from the maximum value.

The chroma calculation unit 120a has a maximum value and a minimum value among all RGB data signals RGB included in one frame data. After selecting, the average value is taken for each RGB data signal (RGB), and the chromaticity can be obtained as the difference value obtained by subtracting the minimum value from the maximum value. When the chroma calculation technique is expressed as an expression, the maximum value "Max = max (R, G, B)", the minimum value "Min = min (R, G, B)", and the chromaticity "Chroma = Max-Min" are expressed.

The chroma calculator 120a supplies the calculated chromaticity information to the color difference calculator 120b and the chroma gain calculator 120e. The chroma gain calculator 120e calculates a gain for the chromaticity based on the chromaticity information calculated by the chroma calculator 120a. The gain value for chromaticity is calculated according to an algorithm determined internally. The chroma gain calculating unit 120e supplies the chroma power gain to the gain calculating unit 120i when power consumption is calculated. The chroma calculation unit 120a and the chroma gain calculation unit 120e calculate a gain for chromaticity, and thus are collectively defined as a first parameter calculation unit.

The color difference calculating unit 120b calculates a color difference for the RGB data signal RGB supplied from the image processing unit. The color difference calculating unit 120b calculates the chromaticity coefficient value (Coeff_Chroma), the red coefficient value (Coeff_R), the green coefficient value (Coeff_G), the blue coefficient value (Coeff_B), and the constant value (Constant) through regression analysis. Can be calculated.

Regression analysis is a technique that not only considers the linear relationship between the independent variable and the dependent variable, but also predicts how the dependent variable changes as the independent variable changes. It is possible to calculate the color difference ΔEab for the signal RGB. When the color difference calculation technique is expressed as a formula, it is expressed as "△ Eab = Coeff_Chroma * Coeff_Chroma + Coeff_R * R + Coeff_G * G + Coeff_B * B + Constant".

How to express the color difference (△ Eab): △ Eab and △ Euv are the definitions of the Uniform Color Space established in 1976, and △ Eab is widely used. The color difference (△ Eab) may also be expressed as "△ Eab = √ ((△ L) 2 + (△ a) 2 + (△ b) 2)", where L is the brightness and a is +, the color of red And-indicates the degree of green color. And if b is +, it indicates the degree of color of yellow, and if-, it indicates the degree of color of blue.

In general, it is reported that a person perceives a change in color when the ΔEab value is 3 or more in a still image, and recognizes a change in color when the ΔEab value is 8 or more in a still image. That is, a person's perspective differs in the degree of perception of a change in color according to a still image and a video.

The color difference calculation unit 120b supplies the calculated color difference information to the color difference gain calculation unit 120f. The color difference gain calculation unit 120f calculates a gain based on the color difference information calculated by the color difference calculation unit 120b and the gain for a motion value calculated by the motion gain calculation unit 120g.

The reason that the color difference gain calculator 120f refers to the gain for the motion value when calculating the gain for the color difference information is to vary the color difference gain according to the motion. When the gain is calculated in this way, the gain of the data signal RGB can be differentially increased or decreased according to the movement. The color difference gain calculating unit 120f supplies the gain to the power consumption reduction unit 120i when the gain for the color difference according to the movement is calculated. Since the color difference calculating unit 120b and the color difference gain calculating unit 120f calculate the gain for the color difference, it is collectively defined as the second parameter calculation unit.

The motion calculation unit 120c calculates whether the RGB data signal RGB supplied from the image processing unit is a still image or a video, as well as an absolute value according to a motion in the case of a video. The motion calculator 120c calculates an average picture level (APL) based on the motion of the image and determines whether the RGB data signal (RGB) supplied from the image processor is a still image or a video based on the calculated average luminance level. Judge whether or not.

The motion calculator 120c determines whether the motion is a difference value obtained by subtracting the current average luminance level (current_APL) from the previous average luminance level (previous_APL). If the technique for calculating the presence or absence of motion is expressed as a formula, it is expressed as "Motion = ABS (previous_APL-present_APL)".

The motion calculator 120c supplies the motion value calculated according to the motion to the motion gain calculator 120g. The motion gain calculator 120g calculates a gain for the motion value based on the motion value calculated by the motion calculator 120c. The motion gain calculator 120g supplies a gain for the calculated motion value to the color difference gain calculator 120f. Since the motion calculator 120c and the motion gain calculator 120g calculate the gain for the motion value, they are collectively defined as the third parameter calculator.

The first data conversion unit 120d converts the RGB data signal RGB supplied from the image processing unit into a color space capable of calculating luminance. The first data conversion unit 120d converts the RGB data signal RGB into a color space of YUV, Y-Pr-Pb, YCbCr or Y'CbCr and calculates luminance from them. The first data conversion unit 120d supplies the calculated luminance information to the edge calculation unit 120h.

The edge calculator 120h calculates the edge information of the image (or image) based on the data-converted color space. The edge calculating unit 120h may calculate the number of edges of the entire image through a partial feature extraction technique, for example, a 3 * 3 Sobel Filter.

When the number of edges of an image (or image) is calculated using the edge calculator 120h, the degree of complexity of the corresponding image can be determined. Humans are less aware of the color changes that appear in complex images (or images). Therefore, when calculating the edge information, it is possible to lower the power consumption by varying the gain according to the complexity of the image (or image).

The edge calculating unit 120h supplies the calculated edge information to the edge gain calculating unit 120j. The edge gain calculating unit 120j calculates the edge gain based on the edge information and supplies the calculated edge gain to the power consumption reduction gain calculating unit 120i. The edge calculating unit 120h and the edge gain calculating unit 120j calculate the gain for the edge, and thus are collectively defined as the fourth parameter calculating unit.

The power consumption reduction gain calculating unit 120i calculates a gain that controls the color of the RGB data signal RGB so as to lower the power consumption of the display panel in response to the characteristics of the image. The power consumption reduction gain calculating unit 120i calculates a gain that controls the color of the RGB data signal RGB as a result of combining chromaticity gain, color difference gain, and edge gain. However, the part for calculating the edge gain may be omitted or deleted as necessary.

The gain of the power consumption reduction gain calculating unit 120i controls the gain of the data signal RGB between the still image and the video to be variable, and in the case of the video, the gain of the data signal RGB is differentially adjusted according to the movement. Increase or decrease.

The power consumption reduction gain calculating unit 120i corrects the data signal RGB to minimize human perception in still images by comprehensively reflecting parameters related to human perception characteristics, and the data signal ( RGB) to calculate the gain that can be corrected. That is, the power consumption reduction gain calculator 120i basically uses a color difference (ΔEab) that reflects a person's cognitive characteristics when adjusting the gain of the RGB data signal as a reference parameter, and comprehensive arithmetic method along with other related parameters. Adjust the gain of the RGB data signal.

Based on this, when the signal was corrected so that human perception was minimized in the still image, the experiment result was found to be able to lower the power consumption by about 2% to 5%. And, when the signal is corrected so that human perception is minimized in the video, the experimental result was found to be able to lower the power consumption by about 4% to 10%. However, the above result may be different depending on the characteristics of the data signal, the method of calculating the gain, and the type of the parameter, and thus should be interpreted as an example.

9, the data control unit 130 includes a second data conversion unit (130a, RGB to RGBW), a data compensation unit (130b, LIMO) and a peak luminance control unit (130c, Peak Luminance Control) .

The second data conversion unit 130a converts the RGB type data signal RGB supplied from the power consumption reduction gain calculation unit 120i into an RGBW type data signal RGBW. The reason for converting the RGB-type data signal RGB to the RGBW-type data signal RGBW by using the second data converter 130a is to drive the display panel including the RGBW sub-pixels.

The data compensation unit 130b compensates based on an algorithm (or equation) determined therein, so that a color is expressed in a desired target color coordinate on the display panel, and the RGBW type data signal (RGBW) supplied from the second data conversion unit 130a Compensates. When the color coordinate of W displayed on the display panel is different from the target value by the compensation of the data compensation unit 130b, one or more of the remaining RGBs additionally participate in light emission. That is, when the color coordinates of the W sub-pixels are different from the target value, the data compensation unit 130b serves to set the color coordinates different from the target value to a desired color coordinate by emitting the remaining RGB as much as necessary.

The peak luminance control unit 130c generates and outputs a luminance control signal (PLCS) for controlling luminance by at least one frame by referring to the average luminance level and the look-up table stored in the optical compensation memory unit 135. The peak luminance control unit 130c controls luminance in a plurality of frame units (for each frame bundle) using the average luminance level.

Meanwhile, the data adjustment unit 130 may further include other devices in addition to the second data conversion unit 130a, RGB to RGBW, data compensation unit 130b, LIMO and peak luminance control unit 130c, Peak Luminance Control described above. Can be. In addition, although the cognitive gain control unit 120 and the data control unit 130 are described as being separated from each other, they may be integrated into one.

Hereinafter, a description related to the cognitive gain control unit is added to help understand the embodiments of the present invention.

FIG. 10 is a graph showing the relationship between power consumption and motion according to gain control of the cognitive gain control unit, and FIG. 11 shows a relationship between power consumption and motion when differentially increasing or decreasing according to movement when adjusting the gain of the cognitive gain control unit. It is the graph shown.

As illustrated in FIG. 10, according to the gain control function of the cognitive gain control unit, power consumption corresponds to P3 in the case of M1 where movement is relatively small compared to M2 and M3. P3 consumes higher power than P1 and P2. According to the gain control function of the cognitive gain control unit, the power consumption corresponds to P1 in the case of M3 where the movement is relatively large compared to M1 and M2. P1 consumes less power than P2 and P3.

As described above, a person exhibits a high cognitive ability for color change in an image with little or no motion (still image) and a low cognitive ability for a color change in a relatively moving image (video).

Therefore, the cognitive gain control unit lowers one or more of chromaticity, color difference, and edge gain for images with little or no movement. On the other hand, the cognitive gain control unit increases one or more of chromaticity, color difference, and edge gain for an image with a lot of motion. That is, since the cognitive gain control unit adjusts the gain in the above manner, it is possible to reduce power consumption within a range in which a person does not feel a decrease in display quality.

As illustrated in FIG. 11, according to the gain control function of the cognitive gain control unit, power consumption may be adjusted step-by-step (stepped) according to whether there is a lot of movement or not. For example, even in the case of the same video, there are differences in the amount of motion in the N-1th frame and the Nth frame even though there are many motions and the motions are divided into frames with little motion and many motions.

The cognitive gain control unit can calculate and determine this by various parameters described above, so in detail, it increases or decreases power consumption by increasing or decreasing one or more of chromaticity, color difference, and edge gain in steps (stepwise) depending on whether there is a lot of movement or not. You can save.

12 to 14 are views showing a light emission form of the RGBW sub-pixel according to the gain control of the cognitive gain control unit.

12, the RGBW sub-pixel RGBW was intended to emit light in the form of (a), but emits light in the form of (b) by adjusting the gain of the cognitive gain control unit. By adjusting the gain of the cognitive gain control unit, the light emission amount of the W sub-pixel increases while the light emission amount of the RB sub-pixel RB decreases. At this time, the emission reduction amount of the RB sub-pixel RB may be the same or different.

As illustrated in FIG. 13, the RGBW sub-pixel RGBW was intended to emit light in the form of (a), but emits light in the form of (b) by adjusting the gain of the cognitive gain control unit. By adjusting the gain of the cognitive gain control unit, the emission amount of the W sub-pixel increases while the emission amount of the RGB sub-pixel RGB decreases. At this time, the emission reduction amount of the RGB sub-pixel RGB may be the same or different.

As shown in FIG. 14, the RGBW sub-pixel RGBW was intended to emit light in the form of (a), but emits light in the form of (b) by adjusting the gain of the cognitive gain control unit. By adjusting the gain of the cognitive gain control unit, the emission amount of the W sub-pixel decreases while the emission amount of the G sub-pixel G increases. At this time, the increase amount of light emission of the G sub-pixel G may be the same or different.

Meanwhile, FIGS. 12 to 14 are not limited to this, because the RGBW sub-pixels are only provided to help understand how the RGBW sub-pixel emits light according to the gain control of the cognitive gain control unit.

Hereinafter, a method of driving an organic light emitting display device according to an embodiment of the present invention will be described.

15 is a flowchart illustrating a method of driving an organic light emitting display device according to an embodiment of the present invention.

As illustrated in FIG. 15, the driving method of the organic light emitting display device starts from the chroma calculation step (S110, Chroma Cal) and proceeds in the order of the RGB data signal correction step (S200, RGB correction with CPR gain). However, the illustrated steps are arranged in time series for convenience of explanation, and do not necessarily have to be progressed in the corresponding order.

In the chroma calculation step (S110, Chroma Cal), the chromaticity (or saturation) of the RGB data signal supplied from the image processing unit is calculated. In the chroma calculation step (S110), the maximum and minimum values of the RGB data signals are calculated, and chromaticity is calculated as a difference value obtained by subtracting the minimum value from the maximum value.

In the chroma calculation step (S110), the maximum and minimum values of the RGB data signals are extracted, and the chromaticity of each pixel is calculated using the difference between the maximum value and the minimum value. When the chroma calculation technique is expressed as an expression, the maximum value "Max = max (R, G, B)", the minimum value "Min = min (R, G, B)", and the chromaticity "Chroma = Max-Min" are expressed.

In the color difference calculation steps (S120, ΔEab Cal), the color difference for the RGB data signal supplied from the image processing unit is calculated. In the step of calculating the color difference (S120), the color difference is calculated by calculating the chromaticity coefficient value (Coeff_Chroma), the red coefficient value (Coeff_R), the green coefficient value (Coeff_G), the blue coefficient value (Coeff_B), and the constant value (Constant) through regression analysis. Can be calculated.

Regression analysis is a technique that not only considers the linear relationship between the independent variable and the dependent variable, but also predicts how the dependent variable changes as the independent variable changes. It is possible to calculate the color difference (ΔEab) for the signal. When the color difference calculation technique is expressed as a formula, it is expressed as "△ Eab = Coeff_Chroma * Coeff_Chroma + Coeff_R * R + Coeff_G * G + Coeff_B * B + Constant".

How to express the color difference (△ Eab): △ Eab and △ Euv are the definitions of the Uniform Color Space established in 1976, and △ Eab is widely used. The color difference (△ Eab) may also be expressed as "△ Eab = √ ((△ L) 2 + (△ a) 2 + (△ b) 2)", where L is the brightness and a is +, the color of red And-indicates the degree of green color. And if b is +, it indicates the degree of color of yellow, and if-, it indicates the degree of color of blue.

In general, it is reported that a person perceives a change in color when the ΔEab value is 3 or more in a still image, and recognizes a change in color when the ΔEab value is 8 or more in a still image. That is, a person's perspective differs in the degree of perception of a change in color according to a still image and a video.

In the motion calculation step (S130, Motion Cal), whether the RGB data signal supplied from the image processing unit is a still image or a video, as well as a video, the absolute value according to the motion is calculated. In the motion calculation step (S130), an average picture level (APL) is calculated based on the motion of the image, and it is determined whether the RGB data signal supplied from the image processing unit is a still image or a video based on the calculated average luminance level. do.

In the motion calculation step (S130), it is determined whether the motion is a difference value obtained by subtracting the current average luminance level (current_APL) from the previous average luminance level (previous_APL). If the technique for calculating the presence or absence of motion is expressed as a formula, it is expressed as "Motion = ABS (previous_APL-present_APL)".

In the edge calculation step (S140, Edge Cal), the RGB data signal supplied from the image processing unit is converted into a color space capable of calculating luminance, and edge information of an image (or image) is calculated based on the data-converted color space. . In the edge calculating step (S140), the number of edges of the entire image may be calculated through a partial feature extraction technique, for example, a 3 * 3 Sobel Filter.

By calculating the number of edges of an image (or image) using a feature extraction technique such as a Sobel Filter, the degree of complexity of the image can be determined. Humans are less aware of the color changes that appear in complex images (or images). Therefore, when calculating the edge information, it is possible to lower the power consumption by varying the gain according to the complexity of the image (or image).

In the chroma gain calculation step (S150, Chroma Gain), the gain for the chromaticity is calculated based on the chromaticity information calculated in the chroma calculation step (S110). The gain value for chromaticity is calculated according to an algorithm determined internally.

In the motion gain calculation step (S160, Motion Gain), the gain for the motion value is calculated based on the motion value calculated by the motion calculation step (S130). The gain for the motion value is calculated according to an algorithm determined internally.

In the color difference gain calculation steps S170 and ΔEab Gain, the gain is calculated based on the color difference information calculated by the color difference calculation step S120 and the gain of the motion value calculated by the motion gain calculation step S160. The reason for referring to the gain for the motion value when calculating the gain for the color difference information in the color difference gain calculating step S170 is to vary the color difference gain according to the motion. When the gain is calculated in this way, the gain of the data signal can be differentially increased or decreased according to the movement.

In the edge gain calculation step (S180, Edge Gain), the edge gain is calculated based on the edge information. If the gain is varied according to the degree of complexity of the image (or image) based on the edge information, power consumption can be reduced.

In the step of calculating the power consumption reduction gain (S190, CPR Gain), the gain of controlling the color of the RGB data signal is calculated to reduce the power consumption of the display panel in response to the characteristics of the image. In the step of calculating the power consumption reduction gain (S190), a gain for controlling the color of the RGB data signal is calculated as a result of combining chromaticity gain, color difference gain, and edge gain.

In the step of calculating the power consumption reduction gain (S190), the color difference (△ Eab) reflecting the cognitive characteristics of the person is basically used as a reference parameter when adjusting the gain of the RGB data signal. Adjust the gain of the data signal. However, the part for calculating the edge gain may be omitted or deleted as necessary. Reduction in power consumption The gain of the RGB data signal between the still image and the video is variably adjusted by the gain calculated in the gain calculation step (S190), and in the case of a video, it is differentially increased or decreased according to movement.

In the RGB data signal correction step (S200, RGB correction with CPR Gain), data signals are corrected so that human perception is minimized in still images by comprehensively reflecting parameters related to human perception characteristics, and data are minimized to minimize human perception in movies. Correct the signal.

The RGB data signal corrected as described above is corrected into an RGBW data signal through various image processing processes, and then supplied to the display panel. At this time, the peak luminance is also changed based on the corrected RGB data signal. Accordingly, the display panel adjusts the amount of light emission (or usage) of the RGB sub-pixels according to whether it is a still image or a video, the complexity of the image, and the chromaticity (or saturation degree) of the image, so that an effect of reducing power consumption can be expected. do. On the other hand, among the images displayed on the display panel, there is an image with high saturation, such as a pattern. When such an image is input, the emission amount (consumption) of the W sub-pixel may not be controlled for chromaticity control.

The present invention has the effect of reducing power consumption by controlling colors to minimize perception of color changes in an organic light emitting display device (hereinafter abbreviated as RGBW OLED) having a sub-pixel structure including red, green, blue, and white. There is. In addition, the present invention has an effect of reducing power consumption by adjusting the amount of light (or usage) of sub-pixels in response to characteristics of an image such as whether it is a still image or a moving image, complexity of an image, and degree of chromaticity of an image.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the technical configuration of the present invention described above is in other specific forms without changing the technical spirit or essential features of the present invention by those skilled in the art to which the present invention pertains. It will be understood that it can be practiced. Therefore, the above-described embodiments are to be understood in all respects as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. In addition, all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention.

110: image processing unit 120: cognitive gain control unit
130: data control unit 140: timing control unit
150: data driver 160: gate driver
170: display panel
120a, Chroma Cal: Chroma output
120b, △ Eab Cal: Chrominance calculation unit
120c, Motion Cal: Motion calculator
120d, RGB TO Y: 1st data conversion unit
120e, Chroma Gain: Chroma gain calculator
120f, △ Eab Gain: Chrominance gain calculator
120g, Motion Gain: Motion gain calculation unit
120h, Edge Cal: Edge calculator
120i, CPR Gain: Power consumption reduction gain calculation unit
120j, Edge Gain: Edge gain calculator

Claims (13)

A cognitive gain control unit that adjusts the gain of the RGB data signal so that the color is controlled based on a color difference (ΔEab) reflecting a human cognitive characteristic;
A data control unit for converting the RGB data signal to an RGBW data signal and compensating for the RGBW data signal; And
And a display panel for displaying an image based on the RGBW data signal,
The cognitive gain control unit
The chroma (or saturation) for the RGB data signal is calculated, and the gain for the chroma is calculated,
Calculate the color difference for the RGB data signal and calculate the gain for the color difference,
A motion value for determining whether the RGB data signal is a moving picture or a still image is calculated, and a gain for the motion value is calculated,
An edge is calculated to determine the degree of complexity of the RGB data signal, and a gain is calculated for the edge,
The gain of the RGB data signal is adjusted to a result obtained by combining at least one of the gain for the chromaticity, the gain for the chrominance, the gain for the motion value, and the gain for the edge,
The gain of the RGB data signal varies depending on whether the RGB data signal is a moving picture or a still image, but in the case of the moving picture, the gain of the RGB data signal is differentially increased or decreased according to movement. Device. delete delete delete According to claim 1,
The cognitive gain control unit
A first parameter calculation unit for calculating a chroma (or saturation) for the RGB data signal and calculating a gain for the chroma,
A second parameter calculation unit for calculating a color difference for the RGB data signal and calculating a gain for the color difference;
A third parameter calculating unit for calculating a motion value for determining whether the RGB data signal is a moving picture or a still image, and calculating a gain for the motion value;
An organic electroluminescent display device comprising a fourth parameter calculator for calculating an edge and calculating a gain for the edge to determine the complexity of the RGB data signal. The method of claim 5,
The cognitive gain control unit
An organic electroluminescent display device comprising a power consumption reduction gain calculating unit for adjusting the gain of the RGB data signal as a result obtained by combining gains obtained from at least one of the first to fourth parameter calculation units. The method of claim 6,
The cognitive gain control unit
Adjusting the gain of the RGB data signal so that the emission amount (or usage amount) of the sub-pixels included in the display panel is varied according to whether it is a still image or a video, the complexity of the image, and the chromaticity (or saturation degree) of the image. Organic light emitting display device, characterized in that. The method of claim 5,
The first parameter calculation unit
An organic light emitting display device comprising calculating the maximum value and the minimum value among the RGB data signals and calculating the chromaticity as a difference value obtained by subtracting the minimum value from the maximum value. The method of claim 5,
The second parameter calculation unit
An organic electroluminescence display device characterized by calculating a color difference by calculating chromaticity coefficient values, red coefficient values, green coefficient values, blue coefficient values, and constant values through regression analysis. Calculating a chroma (or saturation) for the RGB data signal and calculating a gain for the chroma;
Calculating a color difference for the RGB data signal and calculating a gain for the color difference;
Calculating a motion value for determining whether the RGB data signal is a video or a still image, and calculating a gain for the motion value;
Calculating an edge to determine the degree of complexity of the RGB data signal and calculating a gain for the edge; And
And adjusting the gain of the RGB data signal to a result obtained by combining at least one of the gain for the chromaticity, the gain for the chrominance, the gain for the motion value, and the gain for the edge,
The gain of the RGB data signal varies depending on whether the RGB data signal is the video or the still image, but in the case of the video, an organic electric field characterized in that the gain of the RGB data signal is differentially increased or decreased according to movement. Method of driving a light emitting display device. The method of claim 10,
The step of calculating the gain for the chromaticity
A method of driving an organic light emitting display device, comprising calculating a maximum value and a minimum value among the RGB data signals and calculating a chromaticity as a difference value obtained by subtracting the minimum value from the maximum value. The method of claim 10,
The step of calculating the gain for the color difference is
A method of driving an organic light emitting display device characterized by calculating a color difference by calculating chromaticity coefficient values, red coefficient values, green coefficient values, blue coefficient values, and constant values through regression analysis. According to claim 1,
The cognitive gain control unit
In order to reduce power consumption of the display panel, one or more of the chromaticity, the chrominance for the RGB data signal and the gain for the edge are increased or decreased step by step (stepped) according to whether the movement is large or small. Organic electroluminescent display device.

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