Light emitting display device and driving method thereof

Abstract

Disclosed are a light-emitting display device and a driving method thereof. The present invention provides a light-emitting display device including a display panel, comprising a red sub-pixel, a green sub-pixel, a blue sub-pixel and a white sub-pixel; a driver configured to drive the display panel; and a timing controller configured to control the driver, wherein when the display panel displays an image, a W peak luminance from the white sub-pixel is higher than a sum of RGB peak luminances from the red sub-pixel, the green sub-pixel and the blue sub-pixel.

Description

TECHNICAL FIELD

[0001] The present application relates to a light emitting display apparatus and a driving method thereof. BACKGROUND

[0002] With the development of information technology, the market for display apparatuses, which are a medium for connecting users and information, is growing. Accordingly, display apparatuses such as light emitting display (LED) apparatuses, quantum dot display (QOD) apparatuses, and liquid crystal display (LCD) apparatuses are increasingly used.

[0003] The above-described display apparatus includes a display panel including sub-pixels, a driver outputting a driving signal for driving the display panel, a power supply generating power to be supplied to the display panel or the driver, and the like.

[0004] In the above-described display apparatus, when a driving signal (e.g., a scan signal and a data signal) is supplied to a sub-pixel formed in the display panel, the selected sub-pixel transmits light or directly emits light, thereby displaying an image. SUMMARY

[0005] An object of the present application is to reduce power consumption while implementing image quality enhancement for increasing W luminance in consideration of color additivity.

[0006] To achieve these objects and other advantages and in accordance with the purpose of the present application, as embodied and broadly described herein, a light emitting display apparatus includes a display panel including a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel, a driver configured to drive the display panel, and a timing controller configured to control the driver, wherein a W peak luminance from the white sub-pixel is higher than a sum of RGB peak luminances from the red sub-pixel, the green sub-pixel, and the blue sub-pixel when the display panel displays an image.

[0007] The timing controller can calculate at least one of a first average image level not considering a chroma component and a second average image level considering the chroma component from an input image when calculating an average image level of an image to be displayed on the display panel.

[0008] The timing controller can generate a peak luminance control signal for controlling the W peak luminance to be higher than the sum of the RGB peak luminances based on the second average image level.

[0009] The second average image level can be calculated based on the following equation, second average image level = (total pixel sum(MAX(R, G, B) / 255x((MAX(R, G, B)-(1-chroma gain)xMIN(R, G, B)) / MAX(R, G, B))) / total pixel count)x100, where the total pixel sum is the sum of all pixels, the MAX(R, G, B) is the maximum value of the RGB data signal, the MIN(R, G, B) is the minimum value of the RGB data signal, the chroma gain is a gain value according to a chroma component, and the total pixel count is a count value of all pixels.

[0010] The timing controller can generate a peak luminance control signal for independently controlling W luminance from the white sub-pixel and independently controlling RGB luminance from the red sub-pixel, the green sub-pixel, and the blue sub-pixel, respectively.

[0011] When a predetermined number of white images exist in an input image, the timing controller can generate a peak luminance control signal for reducing W luminance from the white sub-pixel without changing RGB luminance from the red sub-pixel, the green sub-pixel, and the blue sub-pixel.

[0012] When a predetermined number of white images exist in an input image, the timing controller can generate a peak luminance control signal for increasing W luminance from the white sub-pixel without changing RGB luminance from the red sub-pixel, the green sub-pixel, and the blue sub-pixel.

[0013] When a predetermined number of white images exist in an input image, the timing controller can generate a peak luminance control signal for reducing W luminance from the white sub-pixel without increasing RGB luminance from the red sub-pixel, the green sub-pixel, and the blue sub-pixel.

[0014] When a predetermined number of white images exist in an input image, the timing controller can generate a peak luminance control signal for increasing W luminance from the white sub-pixel without reducing RGB luminance from the red sub-pixel, the green sub-pixel, and the blue sub-pixel.

[0015] In another aspect of the present application, a method of driving a light emitting display apparatus including a display panel including red, green, blue and white sub-pixels, a driver for driving the display panel, and a timing controller for controlling the driver, the method includes calculating at least one of a first average image level not considering chroma components and a second average image level considering chroma components from an input image, and generating a peak luminance control signal based on the first average image level or the second average image level, wherein a W peak luminance from the white sub-pixel is higher than a sum of RGB peak luminances from the red, green and blue sub-pixels when the display panel displays an image.

[0016] The second average image level can be calculated based on the following equation, second average image level = (total pixel sum(MAX(R, G, B) / 255x((MAX(R, G, B)-(1-chroma gain)xMIN(R, G, B)) / MAX(R, G, B))) / total pixel number)x100, wherein the total pixel sum is a sum of all pixels, the MAX(R, G, B) is a maximum value of RGB data signals, the MIN(R, G, B) is a minimum value of the RGB data signals, the chroma gain is a gain value according to chroma components, and the total pixel number is a count value of all pixels.

[0017] In another aspect of the present application, a light emitting display apparatus includes a display panel including red, green, blue and white sub-pixels, a driver configured to drive the display panel, and a timing controller configured to control the driver, calculates an average image level considering chroma components from an input image, and generates a peak luminance control signal based on the average image level, the peak luminance control signal for controlling a W peak luminance from the white sub-pixel to be higher than a sum of RGB peak luminances from the red, green and blue sub-pixels.

[0018] The display panel can display an image in which the W peak luminance is higher than the sum of the RGB peak luminances in response to the peak luminance control signal.

[0019] The average image level can be calculated based on the following equation, Average image level = (Total pixel sum(MAX(R, G, B) / 255x((MAX(R, G, B)-(1- chroma gain)xMIN(R, G, B)) / MAX(R, G, B))) / Total pixel count)x100, where the total pixel sum is a sum of all pixels, the MAX(R, G, B) is a maximum value of the RGB data signal, the MIN(R, G, B) is a minimum value of the RGB data signal, the chroma gain is a gain value according to a chroma component, and the total pixel count is a count value of all pixels. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a block diagram schematically illustrating a light emitting display apparatus, and Figure 2 is a configuration diagram schematically illustrating Figure 1 the sub-pixels shown.

[0021] Figure 3 and Figure 4 is a diagram for explaining a configuration of a gate-in-panel type scan driver, Figure 5A and Figure 5B is a diagram showing an arrangement example of a gate-in-panel type scan driver.

[0022] Figures 6 to 9 is a diagram for describing a light emitting display apparatus according to an embodiment of the present application, Figure 10 is a diagram showing a peak luminance control curve for explaining a peak luminance control method according to an embodiment compared with a peak luminance control method according to a comparative example, and Figures 11 to 14 is a diagram showing a luminance control curve for explaining a difference between a peak luminance control method according to a comparative example and a peak luminance control method according to an embodiment.

[0023] Figures 15 to 18 is an example diagram showing a difference between a peak luminance control method according to a comparative example and a peak luminance control method according to an embodiment. DETAILED DESCRIPTION

[0024] The display apparatus according to the present application can be implemented as a television, a video player, a personal computer (PC), a home theater, a car electronics, a smart phone, etc., but the present application is not limited thereto. The display apparatus according to the present application can be implemented as a light emitting display (LED) apparatus, a quantum dot display (QOD) apparatus, a liquid crystal display (LCD) apparatus, etc. However, for convenience of description, a light emitting display apparatus based on direct light emission of inorganic light emitting diodes or organic light emitting diodes will be exemplarily illustrated below.

[0025] Figure 1 is a block diagram schematically illustrating a light emitting display apparatus, Figure 2is schematically shown Figure 1 a configuration diagram of subpixels shown.

[0026] As Figure 1 and Figure 2 As shown, the light emitting display apparatus can include an image provider 110, a timing controller 120, a scan driver 130, a data driver 140, a display panel 150, a power supply 180, etc.

[0027] The image provider (group or host system) 110 can output various driving signals along with an image data signal provided from the outside or an image data signal stored in an internal memory. The image provider 110 can provide a data signal and various driving signals to the timing controller 120.

[0028] The timing controller 120 can output a gate timing control signal GDC for controlling an operation timing of the scan driver 130, a data timing control signal DDC for controlling an operation timing of the data driver 140, and various synchronization signals (a vertical synchronization signal Vsync and a horizontal synchronization signal Hsync). The timing controller 120 can provide the data signal DATA provided from the image provider 110 to the data driver 140 together with the data timing control signal DDC. The timing controller 120 can take the form of an integrated circuit (IC) and be mounted on a printed circuit board, but is not limited thereto.

[0029] The scan driver 130 can output a scan signal (or a scan voltage) in response to the gate timing control signal GDC provided from the timing controller 120. The scan driver 130 can provide the scan signal to subpixels included in the display panel 150 through gate lines GL1 to GLm. The scan driver 130 can take the form of an IC, or can be directly formed on the display panel 150 in a gate-in-panel structure, but is not limited thereto.

[0030] The data driver 140 can sample and latch the data signal DATA in response to the data timing control signal DDC provided from the timing controller 120, convert a digital data signal into an analog data voltage based on a gamma reference voltage, and output the analog data voltage. The data driver 140 can provide the data voltage to subpixels included in the display panel 150 through data lines DL1 to DLn. The data driver 140 can take the form of an IC, and be mounted on the display panel 150 or mounted on a printed circuit board, but is not limited thereto.

[0031] The power supply 180 can generate first power having a high potential and second power having a low potential based on external input power supplied from the outside, and output the first power and the second power through a first power line EVDD and a second power line EVSS. The power supply 180 can generate and output a voltage required to drive the scan driver 130 (e.g., a gate voltage including a gate high voltage and a gate low voltage) and a voltage required to drive the data driver 140 (a drain voltage including a drain voltage and a half drain voltage) as well as the first power and the second power.

[0032] The display panel 150 can display an image in response to a driving signal including a scan signal and a data voltage, the first power, the second power, etc. The sub-pixel of the display panel 150 directly emits light. The display panel 150 can be manufactured based on a substrate (e.g., glass, silicon, polyimide, etc.) having rigidity or flexibility. Further, the sub-pixel emitting light can include red, green, and blue pixels, or include red, green, blue, and white pixels.

[0033] For example, one sub-pixel SP can be connected to a first data line DL1, a first gate line GL1, a first power line EVDD, and a second power line EVSS, and can include a pixel circuit including a switching transistor, a driving transistor, a capacitor, an organic light emitting diode, etc. Since the sub-pixel SP used in the light emitting display apparatus directly emits light, the circuit structure is complex. Further, there are various compensation circuits for compensating for deterioration of the driving transistor for providing a driving current required to drive the organic light emitting diode emitting light and the organic light emitting diode. Therefore, it is noted that the sub-pixel SP is simply shown in the form of a block.

[0034] Meanwhile, in the above description, the timing controller 120, the scan driver 130, the data driver 140, etc. are described as separate components. However, according to an implementation method of the light emitting display apparatus, one or more of the timing controller 120, the scan driver 130, and the data driver 140 can be integrated into one IC.

[0035] Figure 3 and Figure 4 is a diagram for explaining a configuration of an in-panel gate type scan driver, Figure 5A and Figure 5B is a diagram showing an arrangement example of the in-panel gate type scan driver.

[0036] As Figure 3As shown, the in-panel gate type scan driver 130 can include a shift register 131 and a level shifter 135. The level shifter 135 can generate a driving clock signal Clk and a start signal Vst based on signals and voltages output from the timing controller 120 and the power supply 180. The driving clock signal Clk can be generated in the form of J different phases (J is an integer equal to or greater than 2), such as 2 phases, 4 phases, or 8 phases.

[0037] The shift register 131 operates based on the signals Clks and Vst output from the level shifter 135, and can output scan signals Scan[1] to Scan[m] for turning on or off transistors formed in the display panel. The shift register 131 can take the form of a thin film on the display panel, in a panel gate structure.

[0038] As shown in Figure 3 and Figure 4 , unlike the shift register 131, the level shifter 135 can be independently configured as an IC, or can be included in the power supply 180. However, this is merely an example, and the present application is not limited thereto.

[0039] As shown in Figure 5A and Figure 5B , the shift registers 131a and 131b outputting scan signals in the in-panel gate type scan driver can be disposed in the non-display area NA of the display panel 150. The shift registers 131a and 131b can be disposed in the left and right non-display areas NA of the display panel 150 as shown in Figure 5A , or can be disposed in the upper and lower non-display areas NA of the display panel 150 as shown in Figure 5B . Although examples in which the shift registers 131a and 131b are disposed in the non-display area NA are shown in Figure 5A and Figure 5B , the present application is not limited thereto.

[0040] Figures 6 to 9 is a diagram for explaining a light emitting display apparatus according to an embodiment of the present application, Figure 10 is a graph showing a peak luminance control curve for explaining a peak luminance control method according to an embodiment compared with a peak luminance control method according to a comparative example, and Figures 11 to 14 is a graph showing a luminance control curve for describing a difference between a peak luminance control method according to a comparative example and a peak luminance control method according to an embodiment.

[0041] As shown in Figure 6As shown, the light emitting display apparatus according to an embodiment of the present application can display an image based on a display panel 150 including pixels PIX arranged in a matrix form. One pixel PIX provided in the display panel 150 can include a red sub-pixel SPr, a green sub-pixel SPg, a blue sub-pixel SPb, and a white sub-pixel SPw.

[0042] As shown in (a) to (e), the arrangement order of the red sub-pixel SPr, the green sub-pixel SPg, the blue sub-pixel SPb, and the white sub-pixel SPw included in one pixel PIX can be changed according to the implementation method of the display panel. Figure 7

[0043] As shown in (a) to (e), the arrangement order of the red sub-pixel SPr, the green sub-pixel SPg, the blue sub-pixel SPb, and the white sub-pixel SPw included in one pixel PIX can be changed according to the implementation method of the display panel. Figure 6 Figure 8 As shown, the timing controller 120 can process red, green, and blue data signals (hereinafter referred to as RGB data signals) RGB applied from the image provider 110 to convert them into white, red, green, and blue data signals (hereinafter referred to as WRGB data signals) WRGB and output the WRGB data signals WRGB. In order to drive the display panel 150 including the red sub-pixel SPr, the green sub-pixel SPg, the blue sub-pixel SPb, and the white sub-pixel SPw, the WRGB data signals need to be generated from the RGB data signals by the image processing of the timing controller 120 as described above.

[0044] In addition, the timing controller 120 can output a peak luminance control signal PLCS for changing the gamma voltage values GMA output from the gamma unit 145. The data driver 140 can generate data voltages to be applied to the display panel based on the WRGB data signals WRGB output from the timing controller 120 and the gamma voltage values GMA output from the gamma unit 145. Therefore, in order to control the peak luminance of the display panel, the peak luminance control signal PLCS needs to be generated in response to the image processing of the timing controller 120.

[0045] As shown, the timing controller 120 can perform various types of image processing in order to generate the peak luminance control signal PLCS as well as the white, red, green, and blue data signals WRGB. To this end, the timing controller 120 can include a degamma unit 121, a data conversion unit 122, an image processing unit 123, an average image level calculation unit 124, a saturation control unit 125, a peak luminance control unit 126, a chroma current control unit 127, a chroma peak control unit 128, etc. Figure 9

[0046] ​​​The de-gamma unit 121 can perform de-gamma processing on the RGB data signal RGB included in a frame. The de-gamma unit 121 can perform de-gamma processing on the received inverse gamma data to prevent bit overflow that can be caused during an operation of converting the RGB data signal RGB inputted from the outside into the RGBW data signal RGBW to convert the inverse gamma into a linear form, and then perform bit stretching. The de-gamma unit 121 can perform the bit stretching using a de-gamma look-up table, but is not limited thereto.

[0047] The data conversion unit 122 can be used to convert the RGB data signal RGB outputted through the de-gamma unit 121 into the RGBW data signal RGBW. The data conversion unit 122 can convert the RGB data signal RGB into the RGBW data signal RGBW based on a conversion formula set therein.

[0048] The image processing unit 123 can be used to perform various types of image processing on the RGBW data signal RGBW outputted through the data conversion unit 122. The image processing unit 123 can add or subtract a gain or a specific weight for compensating for the RGBW data signal RGBW. Meanwhile, the data conversion unit 122 and the image processing unit 123 can be integrated as one, and can be referred to as an algorithm processing unit.

[0049] The average image level calculation unit 124 can be used to calculate an average image level by calculating an average representative value of the RGB data signal RGB outputted through the de-gamma unit 121. The average image level calculation unit 124 can calculate the average image level from the RGB data signal RGB or from a YCbCr data signal converted from the RGB data signal RGB.

[0050] The average image level calculation unit 124 can recalculate the average representative value calculated in advance for each specific frame so that the same average image level is applied to a plurality of frames in order to reduce flicker or the like.

[0051] The chroma control unit 125 can be selectively associated with the average image level calculation unit 124 so that a chroma component is further considered during calculation of the average image level. The chroma control unit 125 can have a quantitative chroma component value CHRO depending on the chroma component after extracting and image-processing the chroma component from the RGB data signal RGB.

[0052] The chroma control unit 125 can transmit the chroma component value CHRO to the average picture level calculation unit 124 or can not transmit the chroma component value CHRO to the average picture level calculation unit 124 to be selectively associated with the average picture level calculation unit 124. According to the selective association with the chroma control unit 125, the average picture level calculation unit 124 can calculate a first average picture level APL not considering the chroma component and a second average picture level CAPL considering the chroma component. When the chroma control unit 125 is associated, the average picture level calculation unit 124 calculates the second average picture level CAPL based on the following equation.

[0053] CAPL = (Total Pixel Sum(MAX(R, G, B) / 255 x ((MAX(R, G, B) - (1 - Chroma Gain) x MIN(R, G, B)) / MAX(R, G, B)) / Total Pixel Number) x 100

[0054] In the above equation, the Total Pixel Sum is a sum of all pixels, MAX(R, G, B) is a maximum value of the RGB data signal, MIN(R, G, B) is a minimum value of the RGB data signal, the Chroma Gain is a gain value depending on the chroma component, and the Total Pixel Number is a count value of all pixels. In the above equation, the Chroma Gain can be 0.0 to 1.0.

[0055] It can be determined from the above equation that the chroma component value CHRO transmitted from the chroma control unit 125 to the average picture level calculation unit 124 can correspond to the gain value depending on the chroma component.

[0056] The chroma current control unit 127 and the chroma peak control unit 128 can be selectively associated with the peak luminance control unit 126 so that the current according to the chroma and the peak luminance according to the chroma are controlled when the average picture level calculation unit 124 calculates the second average picture level CAPL.

[0057] The chroma current control unit 127 and the chroma peak control unit 128 generate reference values so that, when the peak luminance control unit 126 generates the peak luminance control signal PLCS, the current value CAPC according to the second average picture level and the peak luminance value CAPP according to the second average picture level are further considered and thus can be integrated into the chroma control unit 125.

[0058] The peak luminance control unit 126 can control the peak luminance of each frame using the first average picture level APL or the second average picture level CAPL calculated by the average picture level calculation unit 124. The peak luminance control unit 126 can output the peak luminance control signal PLCS for changing the gamma voltage value output from the gamma unit based on the first average picture level APL or the second average picture level CAPL.

[0059] Because the control method according to the embodiment controls peak brightness by quantizing chromaticity components, a higher W brightness compared to conventional W brightness can be achieved even if the RGB pure color area is reduced. Therefore, the control method according to the embodiment can increase W brightness while reducing the RGB pure color area and simultaneously reduce power consumption.

[0060] like Figure 10 As shown, in the control method according to the comparative example, the peak brightness PL is determined based on a first average image level (APL) that does not consider chroma components. On the other hand, in the control method according to the embodiment, the peak brightness PL is determined based on a second average image level (CAPL) that considers chroma components. Meanwhile, it should be noted that, for a better understanding of this embodiment, Figure 10 The magnified peak brightness curve of W is shown.

[0061] The control method according to the embodiment can independently control the non-color and color components, so that when the W peak brightness is changed, the RGB peak brightness is maintained without decreasing or changing. Furthermore, in the control method according to this embodiment, the RGB peak brightness and W peak brightness do not change together but change independently; however, the RGB peak brightness and W peak brightness can change according to a correction variable or according to the gain value of the chromaticity component.

[0062] like Figures 11 to 13 As shown, the control method according to the embodiment can achieve the same RGB peak brightness as the comparative example. However, as Figure 14 As shown, compared with the comparative example (reference) Figure 14 Compared to the control methods of the Implementation Method (CAPL), Comparative Example (APL), and Reference Comparative Example (APL), the control method according to the implementation method can increase the peak brightness of W, thereby achieving a peak output corresponding to the efficiency of the elements formed in the display panel. That is, the control method according to this implementation method can control W independently to achieve maximum efficiency without RGB control.

[0063] Typically, while methods for displaying images based on RGBW subpixels can utilize the high efficiency of W subpixels (high-efficiency subpixels) without color filters, it is desirable to consider color additive properties in order to maximize the use of the high efficiency of W subpixels. Therefore, the control method according to the implementation takes into account the chromaticity component values ​​related to color additive properties to calculate an average image level, so as to maximize the high efficiency of W subpixels and adjust the peak brightness of the RGBW subpixels accordingly.

[0064] The following will explain the differences between the control method according to the comparative example and the control method according to the implementation method when each of the RGBW sub-pixels represents a full-size pattern.

[0065] In the comparative example, the image can be expressed with R=20 nit, G=70 nit, B=10 nit, and W=100 nit to match the color ratio. That is, in the comparative example, the relationship of "R peak luminance + G peak luminance + B peak luminance = W peak luminance" can be set such that the sum of the RGB peak luminances is the same as the W peak luminance.

[0066] On the other hand, in the embodiment, the luminance of RGB can be controlled to be lower, and the luminance of W can be controlled to be higher, for example, R=10 nit, G=35 nit, B=5 nit, and W=200 nit, and the luminance of RGB and W can be independently controlled. That is, the embodiment can set the relationship of "R peak luminance + G peak luminance + B peak luminance < W peak luminance", in which the W peak luminance is higher than the sum of the RGB peak luminances.

[0067] Note that the luminance variation width of RGBW can be differently set according to the product to which the display apparatus is applied. Also, it should be noted that, during actual output, the corresponding luminance can be automatically changed according to the output image associated with the chromaticity by an internal algorithm. Also, the luminance W of the display panel can be changed according to the chromaticity.

[0068] The control method according to the embodiment is a method of controlling the luminance according to the chromaticity. Thus, when the display apparatus is driven by the control method according to the embodiment, the W luminance can be higher than the luminance during the default operation (normal operation) when the chromaticity is low. For example, when the luminance in the product is set to 150 nit, when the control method according to the embodiment is used, a luminance of 250 nit or more can be implemented. Also, when operating by the control method according to the embodiment, even if the R luminance set in the product is 50 nit, the image can be displayed at 25 nit because the RGB luminance can be simultaneously reduced.

[0069] Hereinafter, the difference between the control method according to the comparative example and the control method according to the embodiment will be explained when a specific image (for example, an image in which the gray scale of an RGB-based rainbow pattern is gradually changed) is displayed on the display panel and then the luminance is changed.

[0070] In the comparative example, when the image representing the same gray scale in one frame of image is measured, the sum of the RGB luminances (or the sum of the RGB peak luminances) can be different from the W luminance (or the W peak luminance). This is because the luminance is varied in such a way that the RGB luminance or the W luminance is forcibly increased or decreased regardless of the color additivity in the comparative example.

[0071] On the other hand, in this embodiment, when images representing the same gray scale in one frame of image are measured, the sum of RGB luminances (or the sum of RGB peak luminances) can be equal to the W luminance (or the W peak luminance). This is because the luminance is changed (the sum of RGB luminances corresponds to the W luminance) in consideration of color additivity, so that the relationship of RGB luminance = W luminance is maintained in this embodiment.

[0072] Hereinafter, the difference between the peak luminance control method according to the comparative example and the peak luminance control method according to the embodiment will be explained in the presence of a small amount of W images (including the case where no W image is present) and in the presence of a large amount of W images.

[0073] Figures 15 to 18 is an example diagram showing the difference between the peak luminance control method according to the comparative example and the peak luminance control method according to the embodiment.

[0074] When a small amount of W images is present as in the first example of Figure 15 , because independent control can be performed, only the W luminance is reduced without changing the RGB luminance in the control method (CAPL) according to the embodiment, whereas both the RGB luminance and the W luminance can be reduced in the control method (APL) according to the comparative example.

[0075] When a large amount of W images is present as in the second example of Figure 16 , because independent control can be performed, only the W luminance is increased without changing the RGB luminance in the control method (CAPL) according to the embodiment, whereas both the RGB luminance and the W luminance can be increased in the control method (APL) according to the comparative example.

[0076] When a small amount of W images is present as in the third example of Figure 17 , because independent control can be performed, the W luminance can be reduced without increasing the RGB luminance in the control method (CAPL) according to the embodiment, whereas both the RGB luminance and the W luminance can be reduced in the control method (APL) according to the comparative example.

[0077] When a large amount of W images is present as in the fourth example of Figure 18 , because independent control can be performed, the W luminance can be increased without reducing the RGB luminance in the control method (CAPL) according to the embodiment, whereas both the RGB luminance and the W luminance can be increased in the control method (APL) according to the comparative example.

[0078] Referring to Figures 15 to 18In the peak luminance control method according to this embodiment, the luminance of an image closer to W can increase according to chroma, in an example. In this case, since RGB has a peak luminance curve lower than that of W, the luminance can decrease as the chroma increases. In other words, when the chroma is high, the luminance can follow the pure color curve. Simply put, it can be defined as "W image: chroma = 0 -> low APL -> luminance increases" and "RGB image: chroma = 100 -> high APL -> pure color PLC sets luminance."

[0079] However, when the W image and the RGB image are presented together, unlike the above example, the RGB luminance can also increase according to the W luminance. That is, the RGB luminance can also increase simultaneously with the W luminance. This operation is possible because at least one of a first average image level not considering the chroma component and a second average image level considering the chroma component can be calculated according to the input image, and the luminance can be controlled based on the calculated average image level.

[0080] As described above, the present application has the effect of increasing the full white luminance in a range in which the lifespan can be maintained without reducing the picture quality according to the chroma of the input data signal by using the high efficiency characteristics of the W sub-pixel. In addition, the present application has the effect of reducing power consumption while implementing image quality enhancement for increasing the luminance, considering color additivity.

[0081] Cross Reference to Related Applications

[0082] This application claims the benefit of Korean Patent Application No. 10-2021-0193365, filed December 30, 2021, which is hereby incorporated by reference as if fully set forth herein.

Claims

1. A light emitting display apparatus, the light emitting display apparatus comprising: a display panel including red, green, blue and white sub-pixels; a driver configured to drive the display panel; and a timing controller configured to control the driver; wherein, when the display panel displays an image, a W peak luminance from the white sub-pixel is higher than a sum of RGB peak luminances from the red, green and blue sub-pixels, wherein the timing controller calculates at least one of a first average image level not considering a chroma component and a second average image level considering the chroma component from an input image when calculating an average image level for an image to be displayed on the display panel. the timing controller generates a peak luminance control signal for controlling the W peak luminance to be higher than the sum of the RGB peak luminances based on the second average image level.

2. The light-emitting display device according to claim 1, wherein the second average image level is calculated based on the following equation, 3. The light-emitting display device according to claim 1, wherein Second average image level = (Total pixel sum(MAX(R, G, B) / 255 x ((MAX(R, G, B) - (1 - chroma gain) x MIN(R, G, B)) / MAX(R, G, B))) / Total pixel number) x 100, wherein the Total pixel sum is a sum of all pixels, the MAX(R, G, B) is a maximum value of RGB data signals, the MIN(R, G, B) is a minimum value of the RGB data signals, the chroma gain is a gain value according to a chroma component, and the Total pixel number is a count value of all pixels. the timing controller generates a peak luminance control signal for independently controlling a W luminance from the white sub-pixel and independently controlling RGB luminances from the red, green and blue sub-pixels, respectively.

4. The light-emitting display device according to claim 1, wherein when there are a predetermined number of white images in an input image, the timing controller generates a peak luminance control signal for reducing the W luminance from the white sub-pixel without changing the RGB luminances from the red, green and blue sub-pixels.

5. The light-emitting display device according to claim 1, wherein when there are a predetermined number of white images in an input image, the timing controller generates a peak luminance control signal for increasing the W luminance from the white sub-pixel without changing the RGB luminances from the red, green and blue sub-pixels.

6. The light-emitting display device according to claim 1, wherein when there are a predetermined number of white images in an input image, the timing controller generates a peak luminance control signal for reducing the W luminance from the white sub-pixel instead of increasing the RGB luminances from the red, green and blue sub-pixels.

7. The light-emitting display device according to claim 1, wherein when there are a predetermined number of white images in an input image, the timing controller generates a peak luminance control signal for increasing the W luminance from the white sub-pixel instead of reducing the RGB luminances from the red, green and blue sub-pixels.

8. The light-emitting display device according to claim 1, wherein ​ 9. A method of driving a light emitting display device, the light emitting display device comprising: a display panel including red sub-pixels, green sub-pixels, blue sub-pixels, and white sub-pixels; a driver configured to drive the display panel; and a timing controller configured to control the driver, to calculate an average image level taking into account a chroma component from an input image, and to generate a peak luminance control signal based on the average image level, the peak luminance control signal being for controlling a W peak luminance from the white sub-pixels to be higher than a sum of RGB peak luminances from the red sub-pixels, the green sub-pixels, and the blue sub-pixels. the display panel displays an image in which the W peak luminance is higher than the sum of the RGB peak luminances in response to the peak luminance control signal. the average image level is calculated based on the following formula, average image level = (total pixel sum(MAX(R, G, B) / 255 x ((MAX(R, G, B) - (1 - chroma gain)) x MIN(R, G, B)) / MAX(R, G, B))) / total pixel number) x 100, 10. The method of claim 9, wherein, where the total pixel sum is a sum of all pixels, the MAX(R, G, B) is a maximum value of RGB data signals, the MIN(R, G, B) is a minimum value of the RGB data signals, the chroma gain is a gain value according to a chroma component, and the total pixel number is a count value of all pixels.

11. A light emitting display device, the light emitting display device comprising: a display panel including red sub-pixels, green sub-pixels, blue sub-pixels, and white sub-pixels; a driver configured to drive the display panel; and a timing controller configured to control the driver, to calculate an average image level taking into account a chroma component from an input image, and to generate a peak luminance control signal based on the average image level, the peak luminance control signal being for controlling a W peak luminance from the white sub-pixels to be higher than a sum of RGB peak luminances from the red sub-pixels, the green sub-pixels, and the blue sub-pixels. the display panel displays an image in which the W peak luminance is higher than the sum of the RGB peak luminances in response to the peak luminance control signal. the average image level is calculated based on the following formula, 12. The light-emitting display device according to claim 11, wherein average image level = (total pixel sum(MAX(R, G, B) / 255 x ((MAX(R, G, B) - (1 - chroma gain)) x MIN(R, G, B)) / MAX(R, G, B))) / total pixel number) x 100, 13. The light-emitting display device according to claim 11, wherein where the total pixel sum is a sum of all pixels, the MAX(R, G, B) is a maximum value of RGB data signals, the MIN(R, G, B) is a minimum value of the RGB data signals, the chroma gain is a gain value according to a chroma component, and the total pixel number is a count value of all pixels. ​ ​

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