Display device and driving method thereof

Abstract

A display device and a driving method thereof are disclosed. The display device includes: a display panel including a plurality of pixels; a controller that determines a peak brightness based on a black duty ratio that is a ratio of a black insertion period to a sum of an image display period and the black insertion period and a target brightness, and determines gray-scale brightness information representing a plurality of brightness levels corresponding to a plurality of gray scales based on the peak brightness and a target gamma value, and generates gray-scale voltage information representing a plurality of levels corresponding to a plurality of gray scales based on a target white color coordinate and the gray-scale brightness information; a gray-scale voltage generator that generates a plurality of gray-scale voltages having a plurality of levels based on the gray-scale voltage information; and a data driver that supplies, as data voltages, a plurality of gray-scale voltages corresponding to output image data to the plurality of pixels in an image display period, and supplies a black data voltage to the plurality of pixels in a black insertion period.

Description

Technical Field

[0001] The present invention relates to a display device, and more particularly, to a display device that performs peak brightness driving and a driving method of the display device. Background Art

[0002] When displaying a motion picture on a display device such as an organic light emitting display device, image blur or motion blur may occur. To remove or reduce the image blur of these motion pictures, that is, to shorten the motion picture response time (MPRT) of the display device, a peak brightness driving method has been developed. In the peak brightness driving method, a black insertion section for displaying a black image may be inserted within a frame section, and the display panel displays an image at peak brightness to maintain a predetermined average brightness.

[0003] In such a peak brightness driving method, when the black duty ratio, which is the ratio of the black insertion section to the frame section, is changed, it is necessary to change the peak brightness according to the black duty ratio in order to maintain a constant average brightness. However, there is a problem that the gamma value of the display device is not constant as the peak brightness changes. Summary of the Invention

[0004] An object of the present invention is to provide a display device having a constant gamma characteristic even when the peak brightness is changed.

[0005] Another object of the present invention is to provide a driving method of a display device having a constant gamma characteristic even when the peak brightness is changed.

[0006] However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and various extensions can be made without departing from the spirit and scope of the present invention.

[0007] In order to achieve an object of the present invention, a display device according to the present invention includes: a display panel including a plurality of pixels; a controller configured to determine a peak brightness based on a black duty ratio which is a ratio of a black insertion period to a sum of an image display period and the black insertion period and a target brightness, and determine gray-scale brightness information representing a plurality of brightness levels corresponding to a plurality of gray-scales based on the peak brightness and a target gamma value, and generate gray-scale voltage information representing a plurality of voltage levels corresponding to the plurality of gray-scales based on a target white color coordinate and the gray-scale brightness information; a gray-scale voltage generator configured to generate a plurality of gray-scale voltages having the plurality of voltage levels based on the gray-scale voltage information; and a data driver configured to provide, during the image display period, a gray-scale voltage corresponding to output image data among the plurality of gray-scale voltages to the plurality of pixels as a data voltage, and provide a black data voltage to the plurality of pixels during the black insertion period.

[0008] In one embodiment, the plurality of pixels may display an image at a brightness corresponding to the target gamma value during the image display period.

[0009] In one embodiment, the controller may include: a peak brightness calculator configured to determine the peak brightness based on the black duty ratio and the target brightness; a gray-scale brightness calculator configured to determine the gray-scale brightness information based on the peak brightness and the target gamma value; a gray-scale voltage calculator configured to generate the gray-scale voltage information based on the target white color coordinate and the gray-scale brightness information; and a gamma block configured to store the gray-scale voltage information.

[0010] In one embodiment, the peak brightness calculator may calculate the peak brightness using the mathematical formula "PEAK_LUM = TGT_LUM / (1 - BDR)", where PEAK_LUM represents the peak brightness, TGT_LUM represents the target brightness, and BDR represents the black duty ratio.

[0011] In one embodiment, the peak brightness calculator may receive black insertion information representing the black duty ratio from an external host.

[0012] In one embodiment, the controller may further include: a data analyzer configured to analyze input image data to determine the black duty ratio and generate black insertion information representing the black duty ratio, wherein the peak brightness calculator receives the black insertion information from the data analyzer.

[0013] In one embodiment, the gray-scale - luminance calculator calculates the multiple luminances respectively corresponding to the multiple gray-scales by using the mathematical formula "GRAY_LUM = PEAK_LUM*(GRAY / MAX_GRAY)^TGT_GAMMA", where GRAY_LUM can represent luminance, PEAK_LUM represents the peak luminance, GRAY represents the gray-scale, MAX_GRAY represents the maximum gray-scale, and TGT_GAMMA represents the target gamma value.

[0014] In one embodiment, each of the multiple pixels may include a red sub-pixel, a green sub-pixel, and a blue sub-pixel. The gray-scale - luminance calculator may determine multiple red voltage levels for the red sub-pixel, multiple green voltage levels for the green sub-pixel, and multiple blue voltage levels for the blue sub-pixel respectively corresponding to the multiple gray-scales based on the target white color coordinate and the gray-scale - luminance information.

[0015] In one embodiment, the controller may further include: a data - RGB color coordinate block that stores data - RGB color coordinate information representing red color coordinates for the red sub-pixel, green color coordinates for the green sub-pixel, and blue color coordinates for the blue sub-pixel respectively corresponding to multiple data voltage levels; and a data RGB - luminance block that stores data - RGB luminance information representing red luminance for the red sub-pixel, green luminance for the green sub-pixel, and blue luminance for the blue sub-pixel respectively corresponding to the multiple data voltage levels.

[0016] In one embodiment, the gray-scale - voltage calculator may determine the multiple red voltage levels, the multiple green voltage levels, and the multiple blue voltage levels respectively corresponding to the multiple gray-scales based on the target white color coordinate, the gray-scale - luminance information, the data - RGB color coordinate information, and the data - RGB luminance information, and write gray-scale - voltage information representing the multiple red voltage levels, the multiple green voltage levels, and the multiple blue voltage levels respectively corresponding to the multiple gray-scales into the gamma block.

[0017] In one embodiment, the gray-scale voltage generator may read the gray-scale - voltage information from the gamma block and generate the multiple gray-scale voltages having the multiple voltage levels represented by the gray-scale - voltage information.

[0018] In one embodiment, the black data voltage may be the gray-scale voltage corresponding to the lowest gray-scale among the multiple gray-scale voltages.

[0019] To achieve another object of the present invention, a driving method of a display device including a plurality of pixels according to the present invention includes the following steps: determining a peak brightness based on a black duty ratio which is a ratio of a black insertion interval to the sum of an image display interval and the black insertion interval, and a target brightness; determining gray-scale - brightness information representing a plurality of brightnesses corresponding to a plurality of gray-scales based on the peak brightness and a target gamma value; generating gray-scale - voltage information representing a plurality of voltage levels corresponding to the plurality of gray-scales based on a target white color coordinate and the gray-scale - brightness information; generating a plurality of gray-scale voltages having the plurality of voltage levels based on the gray-scale - voltage information; providing, in the image display interval, a gray-scale voltage corresponding to output image data among the plurality of gray-scale voltages to the plurality of pixels as a data voltage, and providing a black data voltage to the plurality of pixels in the black insertion interval.

[0020] In one embodiment, an image that can be displayed by the plurality of pixels in the image display interval has a brightness corresponding to the target gamma value.

[0021] In one embodiment, the step of determining the peak brightness based on the black duty ratio and the target brightness may include the following steps: calculating the peak brightness using the mathematical formula "PEAK_LUM = TGT_LUM / (1 - BDR)", where PEAK_LUM represents the peak brightness, TGT_LUM represents the target brightness, and BDR represents the black duty ratio.

[0022] In one embodiment, it may further include the following step: receiving black insertion information representing the black duty ratio from an external host.

[0023] In one embodiment, it may further include the following step: analyzing input image data to determine the black duty ratio.

[0024] In one embodiment, the step of determining the gray-scale - brightness information based on the peak brightness and the target gamma value may include the following steps: calculating the plurality of brightnesses corresponding to the plurality of gray-scales using the mathematical formula "GRAY_LUM = PEAK_LUM*(GRAY / MAX_GRAY)^TGT_GAMMA", where GRAY_LUM may represent brightness, PEAK_LUM represents the peak brightness, GRAY represents the gray-scale, MAX_GRAY represents the maximum gray-scale, and TGT_GAMMA represents the target gamma value.

[0025] In one embodiment, each of the plurality of pixels may include a red sub-pixel, a green sub-pixel, and a blue sub-pixel. Wherein, the step of generating the gray-scale voltage information based on the target white color coordinate and the gray-scale luminance information may include: determining a plurality of red voltage levels for the red sub-pixel, a plurality of green voltage levels for the green sub-pixel, and a plurality of blue voltage levels for the blue sub-pixel respectively corresponding to the plurality of gray-scales based on the target white color coordinate and the gray-scale luminance information.

[0026] In one embodiment, the plurality of red voltage levels, the plurality of green voltage levels, and the plurality of blue voltage levels are determined based on the target white color coordinate, the gray-scale luminance information, data-RGB color coordinate information, and data-RGB luminance information. The data-RGB color coordinate information represents the red color coordinates for the red sub-pixel, the green color coordinates for the green sub-pixel, and the blue color coordinates for the blue sub-pixel respectively corresponding to the plurality of data voltage levels. The data-RGB luminance information may represent the red luminance for the red sub-pixel, the green luminance for the green sub-pixel, and the blue luminance for the blue sub-pixel respectively corresponding to the plurality of data voltage levels.

[0027] In the display device and the driving method of the display device according to the embodiments of the present invention, the peak luminance may be determined based on the black duty ratio and the target luminance, the gray-scale luminance information may be determined based on the peak luminance and the target gamma value, the gray-scale voltage information may be generated based on the target white color coordinate and the gray-scale luminance information, and a plurality of gray-scale voltages may be generated based on the gray-scale voltage information. Accordingly, even if the peak luminance is changed, the display device according to the embodiments of the present invention may have a certain gamma characteristic.

[0028] However, the effects of the present invention are not limited to the above-mentioned effects, and various expansions can be made without departing from the spirit and scope of the present invention. Description of the Drawings

[0029] Figure 1 is a block diagram showing a display device according to an embodiment of the present invention.

[0030] Figure 2 is a diagram for explaining an example of the operation of a display device according to an embodiment of the present invention.

[0031] Figure 3 is a block diagram showing an example of a controller included in a display device according to an embodiment of the present invention.

[0032] Figure 4It is a diagram for explaining an example of the peak brightness and gamma characteristics when a display device according to an embodiment of the present invention is driven at a black duty ratio of approximately 0%, a black duty ratio of approximately 33%, and a black duty ratio of approximately 50%.

[0033] Figure 5 It is a sequence diagram showing a driving method of a display device according to an embodiment of the present invention.

[0034] Figure 6 It is a diagram for explaining an example of peak brightness according to the black duty ratio.

[0035] Figure 7 It is a diagram for explaining an example of determining gray-scale - brightness information according to the peak brightness.

[0036] Figure 8 It is a diagram for explaining an example of data - RGB color coordinate information stored in a display device according to an embodiment of the present invention.

[0037] Figure 9 It is a diagram for explaining an example of data - RGB brightness information stored in a display device according to an embodiment of the present invention.

[0038] Figure 10 It is a block diagram showing a display device for explaining another embodiment of the present invention.

[0039] Figure 11 It is a block diagram showing an example of a controller included in a display device according to another embodiment of the present invention.

[0040] Figure 12 It is a sequence diagram showing a driving method of a display device according to another embodiment of the present invention.

[0041] Figure 13 It is a block diagram showing an electronic device including a display device according to an embodiment of the present invention.

[0042]

Reference Signs

[0043] 100, 600: Display device 110: Display panel

[0044] 120: Scan driver 130: Gray - scale voltage generator

[0045] 140: Data driver 150, 650: Controller

[0046] 200: Gamma controller 210: Gamma block

[0047] 220: Peak brightness calculator 230: Gray - scale brightness calculator

[0048] 240: Gray-scale - Voltage Calculator 250: Data - RGB Color Coordinate Block

[0049] 260: Data - RGB Luminance Block 660: Data Analyzer Detailed Implementation Manner

[0050] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the figures, and repeated descriptions of the same components are omitted.

[0051] Figure 1 is a block diagram showing a display device according to an embodiment of the present invention, Figure 2 is a diagram for explaining an example of the operation of a display device according to an embodiment of the present invention, Figure 3 is a block diagram showing an example of a controller included in a display device according to an embodiment of the present invention, Figure 4 is a diagram for explaining an example of peak luminance and gamma characteristics when a display device according to an embodiment of the present invention is driven at a black duty ratio of approximately 0%, a black duty ratio of approximately 33%, and a black duty ratio of approximately 50%.

[0052] Referring to Figure 1 , a display device 100 according to an embodiment of the present invention may include: a display panel 110 including a plurality of pixels PX; a scan driver 120 that provides a scan signal SS to the plurality of pixels PX; a gray-scale voltage generator 130 that generates a plurality of gray-scale voltages GV; a data driver 140 that provides a data voltage DV to the plurality of pixels PX based on the plurality of gray-scale voltages GV; and a controller 150 that controls the operation of the display device 100.

[0053] The display panel 110 may include a plurality of data lines, a plurality of scan lines, and a plurality of pixels PX connected to the plurality of data lines and the plurality of scan lines. In one embodiment, the display panel 110 may be an OLED display panel in which each pixel PX includes an organic light emitting diode (OLED). For example, each pixel PX may have the following 3T1C structure, but is not limited thereto. The 3T1C structure includes: a storage capacitor; a switching transistor that transfers a data voltage DV to the storage capacitor; a driving transistor that generates a driving current based on the data voltage DV stored in the storage capacitor; an organic light emitting diode that emits light based on the driving current; and an initialization transistor that connects the anode of the organic light emitting diode to an initialization line (or a sensing line). In another embodiment, each pixel PX may include a switching transistor and a liquid crystal capacitor connected to the switching transistor, and the display panel 110 may be a liquid crystal display (LCD) panel. In still another embodiment, each pixel PX may include an inorganic light emitting diode or a quantum dot light emitting diode, and the display panel 110 may be an inorganic light emitting diode display panel or a quantum dot light emitting diode display panel. However, the display panel 110 is not limited to the LCD panel, the OLED display panel, the inorganic light emitting diode display panel, and the quantum dot light emitting diode display panel, and may be any display panel.

[0054] The scan driver 120 may generate a scan signal SS based on a scan control signal SCTRL received from the controller 150, and provide the scan signal SS to the plurality of pixels PX through the plurality of scan lines. In one embodiment, although the scan control signal SCTRL may include a scan start signal and a scan clock signal, it is not limited thereto. In one embodiment, the scan driver 120 may be integrated or formed in the peripheral portion of the display panel 110. In another embodiment, the scan driver 120 may be implemented as one or more integrated circuits (ICs).

[0055] The grayscale voltage generator 130 can read grayscale-voltage information GVI representing a plurality of voltage levels corresponding to a plurality of grayscales from a gamma block (or a gamma lookup table) 210, and generate a plurality of grayscale voltages GV having the plurality of voltage levels based on the grayscale-voltage information GVI. In one embodiment, each pixel PX includes a red sub-pixel, a green sub-pixel, and a blue sub-pixel. The grayscale-voltage information GVI of the gamma block 210 can represent a red voltage level for the red sub-pixel, a green voltage level for the green sub-pixel, and a blue voltage level for the blue sub-pixel corresponding to each grayscale. The grayscale voltage generator 130 can generate a red grayscale voltage for the red sub-pixel, a green grayscale voltage for the green sub-pixel, and a blue grayscale voltage for the blue sub-pixel as the plurality of grayscale voltages GV. Also, in one embodiment, the grayscale-voltage information GVI of the gamma block 210 represents the plurality of voltage levels corresponding to all grayscales (e.g., 256 grayscales from 0-gray to 255-gray). The grayscale voltage generator 130 can generate a plurality of grayscale voltages GV corresponding to all the grayscales respectively based on the grayscale-voltage information GVI. In another embodiment, the grayscale-voltage information GVI of the gamma block 210 can represent the plurality of voltage levels corresponding to a reference grayscale that is a part of all the grayscales. The grayscale voltage generator 130 can generate a plurality of grayscale voltages GV having the plurality of voltage levels represented by the grayscale-voltage information GVI for the reference grayscale and divide the grayscale voltages GV in the reference grayscale to generate grayscale voltages GV for the grayscales between the reference grayscales. Also, in one embodiment, the grayscale voltage generator 130 can be included in the data driver 140. In another embodiment, the grayscale voltage generator 130 can be located outside the data driver 140.

[0056] The data driver 140 can receive the output image data ODAT and the data control signal DCTRL from the controller 150, receive a plurality of gray-scale voltages GV from the gray-scale voltage generator 130, and provide, in response to the data control signal DCTRL, the plurality of gray-scale voltages GV corresponding to the output image data ODAT to the plurality of pixels PX as data voltages DV through the plurality of data lines. In one embodiment, the data control signal DCTRL may include an output data enable signal, a horizontal start signal, and a load signal, but is not limited thereto. Also, in one embodiment, each frame interval of the display device 100 includes an image display interval for displaying a normal image and a black insertion interval for displaying a black image. The data driver 140 can provide, in the image display interval, the plurality of gray-scale voltages GV corresponding to the output image data ODAT to the plurality of pixels PX as data voltages DV, and can provide a black data voltage to the plurality of pixels PX in the black insertion interval. For example, although the black data voltage may be the gray-scale voltage corresponding to the lowest gray-scale among the plurality of gray-scale voltages GV, it is not limited thereto. Also, in one embodiment, the data driver 140 and the controller 150 may be implemented as a single integrated circuit, and such an integrated circuit may be referred to as a timing controller embedded data driver (TED). In another embodiment, the data driver 140 and the controller 150 may be implemented as separate integrated circuits.

[0057] The controller (e.g., a timing controller (TCON)) 150 can receive the input image data IDAT and the control signal CTRL from an external host processor (e.g., a graphics processing unit (GPU) or a graphics card). In one embodiment, the input image data IDAT may be RGB image data including red image data, green image data, and blue image data. The control signal CTRL may include black insertion information BII indicating whether black can be inserted and / or the black duty ratio. In one embodiment, although the control signal CTRL may further include a vertical synchronization signal, a horizontal synchronization signal, an input data enable signal, a master clock signal, etc., it is not limited thereto. The controller 150 can generate the output image data ODAT, the data control signal DCTRL, and the scan control signal SCTRL based on the input image data IDAT and the control signal CTRL. The controller 150 can control the operation of the data driver 140 by providing the output image data ODAT and the data control signal DCTRL to the data driver 140, and can control the operation of the scan driver 120 by providing the scan control signal SCTRL to the scan driver 120.

[0058] The display device 100 according to an embodiment of the present invention may perform peak brightness driving to remove or reduce image blur of a motion picture, that is, shorten the motion picture response time (MPRT) of the display device 100. In one embodiment, the display device 100 may insert a black insertion interval for displaying a black image within each frame interval, and display an image at a peak brightness higher than that in a case where the black insertion interval is not inserted in the image display interval for displaying a general image within each frame interval to maintain a certain average brightness. For example, as Figure 2 shown, each frame interval FP may include an image display interval IDP for displaying a general image and a black insertion interval BIP for displaying a black image. The data driver 140 may provide a data voltage DV to a plurality of pixels PX in the image display interval IDP to display the general image, and may provide the black data voltage to the plurality of pixels PX in the black insertion interval BIP to display the black image. In one embodiment, the data driver 140 may provide the data voltage DV to the plurality of pixels PX in units of a single pixel row in the image display interval IDP, and provide the black data voltage to the plurality of pixels PX in units of a plurality of pixel rows (for example, 8 pixel rows) in the black insertion interval BIP. In another embodiment, the data driver 140 may provide the black data voltage to the plurality of pixels PX in units of a single pixel row in the black insertion interval BIP.

[0059] In addition, in a case where the black insertion interval BIP is inserted, that is, in a case where the image display interval IDP is reduced, the average brightness of the display device 100 in each frame interval FP may decrease. To prevent such a decrease in the average brightness, that is, to maintain such an average brightness, the display device 100 may display an image at a peak brightness higher than that in a case where the black insertion interval BIP is not inserted in the image display interval IDP. For example, as the black insertion interval BIP increases and the image display interval IDP decreases, the display device 100 may increase the peak brightness in the image display interval IDP. For example, in a case where the brightness in a case where the black insertion interval BIP is not inserted is about 500 nit and the ratio of the black insertion interval BIP to the frame interval FP (or the sum of the image display interval IDP and the black insertion interval BIP), that is, the black duty ratio is about 50%, an image may be displayed at a peak brightness of about 1000 nit in the image display interval IDP to maintain an average brightness of about 500 nit in the frame interval FP.

[0060] However, in an existing display device that performs such peak brightness driving, gamma tuning can be performed in such a way that the existing display device has a gamma characteristic corresponding to a target gamma value at an arbitrary peak brightness (e.g., the maximum peak brightness). In this case, as the peak brightness of the existing display device decreases from the maximum peak brightness at which the gamma tuning has been performed, the gamma value of the existing display device may decrease from the target gamma value. For example, in the case where the gamma tuning is performed at a gamma value of approximately 2.2 at a peak brightness of approximately 1000 nits corresponding to a black duty ratio of approximately 50%, the existing display device may have a gamma value of approximately 2.0 at a peak brightness of approximately 750 nits corresponding to a black duty ratio of approximately 33%, and a gamma value of approximately 1.5 at a peak brightness of approximately 500 nits corresponding to a black duty ratio of approximately 0%. Accordingly, in the existing display device that performs the peak brightness driving, the gamma value may change as the peak brightness changes, and the image quality may deteriorate.

[0061] However, in the display device 100 according to an embodiment of the present invention, the controller 150 may include: a gamma controller 200 that generates gray-scale voltage information GVI corresponding to a peak brightness; and a gamma block 210 that stores the gray-scale voltage information GVI generated by the gamma controller 200. The gamma controller 200 may determine the peak brightness based on a black duty ratio and a target brightness, determine gray-scale brightness information based on the peak brightness and a target gamma value, and generate gray-scale voltage information GVI based on a target white color coordinate and the gray-scale brightness information. The gamma controller 200 may write the gray-scale voltage information GVI into the gamma block 210. The gray-scale voltage generator 130 may generate a plurality of gray-scale voltages GV based on the gray-scale voltage information GVI stored in the gamma block 210. Accordingly, even if the peak brightness is changed, the display device 100 according to an embodiment of the present invention can display an image at a brightness corresponding to a certain gamma value (i.e., the target gamma value) in the image display interval IDP. To perform these operations, as Figure 3 shown, the controller 150 of the display device 100 according to an embodiment of the present invention may include a peak brightness calculator 220, a gray-scale brightness calculator 230, a gray-scale voltage calculator 240, and a gamma block 210. In one embodiment, as Figure 3 shown, the controller 150 may further include a data-RGB color coordinate block 250 and a data-RGB brightness block 260.

[0062] The peak brightness calculator 220 may determine the peak brightness PEAK_LUM based on the black duty ratio, which is the ratio of the black insertion period BIP to the frame period FP (i.e., the sum of the image display period IDP and the black insertion period BIP), and the target brightness TGT_LUM. In one embodiment, the peak brightness calculator 220 may receive black insertion information BII representing the black duty ratio from the external host. Also, in one embodiment, the peak brightness calculator 220 may calculate the peak brightness PEAK_LUM using the mathematical formula "PEAK_LUM = TGT_LUM / (1 - BDR)", where PEAK_LUM represents the peak brightness, TGT_LUM represents the target brightness, and BDR may represent the black duty ratio. For example, when the target brightness TGT_LUM is approximately 500 nit and the black duty ratio is approximately 0%, the peak brightness calculator 220 may determine "500 / (1 - 0)", i.e., a peak brightness PEAK_LUM of approximately 500 nit. In another example, when the target brightness TGT_LUM is approximately 500 nit and the black duty ratio is approximately 33%, the peak brightness calculator 220 may determine "500 / (1 - 0.33)", i.e., a peak brightness PEAK_LUM of approximately 750 nit. In yet another example, when the target brightness TGT_LUM is approximately 500 nit and the black duty ratio is approximately 50%, the peak brightness calculator 220 may determine "500 / (1 - 0.5)", i.e., a peak brightness PEAK_LUM of approximately 1000 nit.

[0063] The gray-scale to luminance calculator 230 may determine gray-scale to luminance information GLI representing a plurality of luminances respectively corresponding to a plurality of gray-scales based on a peak luminance PEAK_LUM and a target gamma value TGT_GAMMA. In one embodiment, the gray-scale to luminance calculator 230 may calculate the plurality of luminances respectively corresponding to the plurality of gray-scales by using the mathematical formula "GRAY_LUM = PEAK_LUM * (GRAY / MAX_GRAY) ^ TGT_GAMMA", where GRAY_LUM represents luminance, PEAK_LUM represents the peak luminance, GRAY represents gray-scale, MAX_GRAY represents the maximum gray-scale, and TGT_GAMMA may represent the target gamma value. For example, in a case where the peak luminance PEAK_LUM is approximately 750 nit, the maximum gray-scale is 255 gray-scales, and the target gamma value TGT_GAMMA is approximately 2.2, the luminance corresponding to 150 gray-scale may be "750 * (150 / 255) ^ 2.2", that is, approximately 233 nit. In one embodiment, the gray-scale to luminance calculator 230 may generate gray-scale to luminance information GLI representing the plurality of luminances respectively corresponding to all gray-scales (e.g., 256 gray-scales from 0-gray-scale to 255-gray-scale). In another embodiment, the gray-scale to luminance calculator 230 may generate gray-scale to luminance information GLI representing the plurality of luminances respectively corresponding to reference gray-scales that are a part of the all gray-scales.

[0064] The gray-scale to voltage calculator 240 may generate gray-scale to voltage information GVI representing a plurality of voltage levels respectively corresponding to the plurality of gray-scales based on a target white color coordinate TGT_WCC and the gray-scale to luminance information GLI, and write the gray-scale to voltage information GVI into the gamma block 210. In one embodiment, the gray-scale to voltage calculator 240 may generate gray-scale to voltage information GVI representing the plurality of voltage levels corresponding to all the gray-scales. In another embodiment, the gray-scale to voltage calculator 240 may generate gray-scale to voltage information GVI representing the plurality of voltage levels corresponding to the reference gray-scales.

[0065] In one embodiment, each pixel PX includes a red sub-pixel, a green sub-pixel, and a blue sub-pixel. The grayscale-voltage calculator 240 can determine a plurality of red voltage levels for the red sub-pixel, a plurality of green voltage levels for the green sub-pixel, and a plurality of blue voltage levels for the blue sub-pixel respectively corresponding to the plurality of grayscales based on the target white color coordinate TGT_WCC and the grayscale-luminance information GLI. In one embodiment, the data-RGB color coordinate block 250 can store data-RGB color coordinate information DAT_RGBCCI representing red color coordinates for the red sub-pixel, green color coordinates for the green sub-pixel, and blue color coordinates for the blue sub-pixel respectively corresponding to a plurality of data voltage levels (with a certain spacing, for example, a spacing of approximately 0.01V). The data-RGB luminance block 260 can store data-RGB luminance (or luminous efficiency) information DAT_RGBLI representing red luminance (or luminous efficiency) for the red sub-pixel, green luminance (or luminous efficiency) for the green sub-pixel, and blue luminance (or luminous efficiency) for the blue sub-pixel respectively corresponding to the plurality of data voltage levels (with a certain spacing, for example, a spacing of approximately 0.01V). And the grayscale-voltage calculator 240 can determine the plurality of red voltage levels, the plurality of green voltage levels, and the plurality of blue voltage levels respectively corresponding to the plurality of grayscales based on the target white color coordinate TGT_WCC, the grayscale-luminance information GLI, the data-RGB color coordinate information DAT_RGBCCI, and the data-RGB luminance information DAT_RGBLI, and write grayscale-voltage information GVI representing the plurality of red voltage levels, the plurality of green voltage levels, and the plurality of blue voltage levels respectively corresponding to the plurality of grayscales into the gamma block 210. For example, the grayscale-voltage calculator 240 can determine the ratios of the red voltage level, the green voltage level, and the blue voltage level having the color coordinates represented by the target white color coordinate TGT_WCC at each grayscale based on the target white color coordinate TGT_WCC and the data-RGB color coordinate information DAT_RGBCCI, and determine the red voltage level, the green voltage level, and the blue voltage level having the luminance represented by the grayscale-luminance information GLI while maintaining the ratios at each grayscale based on the grayscale-luminance information GLI and the data-RGB luminance information DAT_RGBLI.

[0066] The grayscale voltage generator 130 may read grayscale-voltage information GVI from the gamma block 210 and generate a plurality of grayscale voltages GV having the plurality of voltage levels represented by the grayscale-voltage information GVI. The data driver 140 may provide the plurality of grayscale voltages GV corresponding to the output image data ODAT as data voltages DV to the plurality of pixels PX during an image display period IDP. In the display device 100 according to an embodiment of the present invention, since the grayscale-voltage information GVI is generated based on the current peak brightness PEAK_LUM, even if the peak brightness PEAK_LUM is changed, the plurality of pixels PX may display an image at a brightness corresponding to a target gamma value TGT_GAMMA during the image display period IDP. Also, the data driver 140 may provide a black data voltage to the plurality of pixels PX during a black insertion period BIP. In one embodiment, the black data voltage may be the grayscale voltage GV corresponding to the lowest grayscale (e.g., 0-grayscale) among the plurality of grayscale voltages GV.

[0067] For example, in a case where the black insertion information BII indicates a black duty ratio BDR of about 0%, as Figure 4 shown in 310, the frame period FP may have only the image display period IDP, and the peak brightness PEAK_LUM may be about 500 nits. In this case, since the grayscale-voltage information GVI is generated in a manner corresponding to the peak brightness PEAK_LUM of about 500 nits, as Figure 4 shown in 320, the plurality of grayscale voltages GV generated by the grayscale voltage generator 130 based on the grayscale-voltage information GVI may correspond to the target gamma value TGT_GAMMA (e.g., a gamma value of about 2.2). Also, in a case where the black insertion information BII indicates a black duty ratio BDR of about 33%, as Figure 4 shown in 330, the frame period FP may have an image display period IDP corresponding to about 2 / 3 of the frame period FP and a black insertion period BIP corresponding to about 1 / 3 of the frame period FP, and the peak brightness PEAK_LUM of the image display period IDP may be about 750 nits. In this case, since the grayscale-voltage information GVI is generated in a manner corresponding to the peak brightness PEAK_LUM of about 750 nits, as Figure 4 shown in 340, the plurality of grayscale voltages GV generated by the grayscale voltage generator 130 based on the grayscale-voltage information GVI may correspond to the target gamma value TGT_GAMMA (e.g., a gamma value of about 2.2). Also, in a case where the black insertion information BII indicates a black duty ratio BDR of about 50%, as Figure 4As shown in 350, the frame interval FP has an image display interval IDP corresponding to approximately 1 / 2 of the frame interval FP and a black insertion interval BIP corresponding to approximately 1 / 2 of the frame interval FP. The peak luminance PEAK_LUM of the image display interval IDP may be approximately 1000 nits. In this case, since the gray-scale voltage information GVI is generated in a manner corresponding to the peak luminance PEAK_LUM of approximately 1000 nits, as Figure 4 shown in 360, a plurality of gray-scale voltages GV generated by the gray-scale voltage generator 130 based on the gray-scale voltage information GVI may correspond to the target gamma value TGT_GAMMA (for example, a gamma value of approximately 2.2).

[0068] As described above, the display device 100 according to an embodiment of the present invention may determine the peak luminance PEAK_LUM based on the black duty ratio and the target luminance TGT_LUM, determine the gray-scale luminance information GLI based on the peak luminance PEAK_LUM and the target gamma value TGT_GAMMA, generate the gray-scale voltage information GVI based on the target white color coordinate TGT_WCC and the gray-scale luminance information GLI, and generate a plurality of gray-scale voltages GV based on the gray-scale voltage information GVI. Accordingly, even if the peak luminance PEAK_LUM is changed, the display device 100 according to an embodiment of the present invention may have a certain gamma characteristic, that is, a gamma characteristic of a certain target gamma value TGT_GAMMA.

[0069] Figure 5 is a sequence diagram showing a driving method of a display device according to an embodiment of the present invention, Figure 6 is a diagram for explaining an example of the peak luminance according to the black duty ratio, Figure 7 is a diagram for explaining an example of determining the gray-scale luminance information according to the peak luminance, Figure 8 is a diagram for explaining an example of data - RGB color coordinate information stored in a display device according to an embodiment of the present invention, Figure 9 is a diagram for explaining an example of data - RGB luminance information stored in a display device according to an embodiment of the present invention.

[0070] Referring to Figure 1 、 Figure 3 and Figure 5, in a driving method of a display device 100 including a plurality of pixels PX, a peak brightness calculator 220 may receive black insertion information BII representing a black duty ratio, which is a ratio of a black insertion period to a sum of an image display period and the black insertion period, from an external host, and may determine a peak brightness PEAK_LUM based on the black duty ratio and a target brightness TGT_LUM (S410). In an embodiment, the peak brightness calculator 220 may calculate the peak brightness PEAK_LUM using the mathematical formula "PEAK_LUM = TGT_LUM / (1 - BDR)", where PEAK_LUM represents the peak brightness, TGT_LUM represents the target brightness, and BDR may represent the black duty ratio. For example, as Figure 6 shown, when the target brightness TGT_LUM is approximately 500 nit and the black duty ratio BDR is approximately 0%, the peak brightness calculator 220 may determine "500 / (1 - 0)", that is, a peak brightness PEAK_LUM of approximately 500 nit. In another example, when the target brightness TGT_LUM is approximately 500 nit and the black duty ratio BDR is approximately 33%, the peak brightness calculator 220 may determine "500 / (1 - 0.33)", that is, a peak brightness PEAK_LUM of approximately 750 nit. In yet another example, when the target brightness TGT_LUM is approximately 500 nit and the black duty ratio BDR is approximately 50%, the peak brightness calculator 220 may determine "500 / (1 - 0.5)", that is, a peak brightness PEAK_LUM of approximately 1000 nit.

[0071] A gray-scale brightness calculator 230 may determine gray-scale brightness information GLI representing a plurality of brightness levels corresponding to a plurality of gray-scales based on the peak brightness PEAK_LUM and a target gamma value TGT_GAMMA (S420). In an embodiment, the gray-scale brightness calculator 230 may calculate the plurality of brightness levels corresponding to the plurality of gray-scales using the mathematical formula "GRAY_LUM = PEAK_LUM * (GRAY / MAX_GRAY)^TGT_GAMMA" as Figure 7 shown, where GRAY_LUM represents the brightness, PEAK_LUM represents the peak brightness, GRAY represents the gray-scale, MAX_GRAY represents the maximum gray-scale, and TGT_GAMMA may represent the target gamma value. For example, when the maximum gray-scale is 255 gray-scales (255G) and the target gamma value TGT_GAMMA is approximately 2.2, the brightness corresponding to 150 gray-scales (155G) may be "PEAK_LUM * (150 / 255)^2.2" (nit).

[0072] The grayscale-voltage calculator 240 may generate grayscale-voltage information GVI representing a plurality of voltage levels corresponding to the respective ones of the plurality of grayscales based on a target white color coordinate TGT_WCC and grayscale-luminance information GLI (S430). In one embodiment, each pixel PX includes a red sub-pixel, a green sub-pixel, and a blue sub-pixel, and the grayscale-voltage calculator 240 may generate grayscale-voltage information GVI representing a plurality of red voltage levels for the red sub-pixel, a plurality of green voltage levels for the green sub-pixel, and a plurality of blue voltage levels for the blue sub-pixel corresponding to the respective ones of the plurality of grayscales based on the target white color coordinate TGT_WCC, the grayscale-luminance information GLI, data-RGB color coordinate information DAT_RGBCCI, and data-RGB luminance information DAT_RGBLI.

[0073] In one embodiment, the data-RGB color coordinate block 250 may store data-RGB color coordinate information DAT_RGBCCI representing red color coordinates for the red sub-pixel, green color coordinates for the green sub-pixel, and blue color coordinates for the blue sub-pixel corresponding to the respective ones of a plurality of data voltage levels (with a certain spacing, for example, with a spacing of approximately 0.01V). For example, as Figure 8 shown, the data-RGB color coordinate information DAT_RGBCCI may include, as the red color coordinate CC, an X-color coordinate Rx of approximately 0.710 that is constant for the red sub-pixel according to the data voltage level DVL and a Y-color coordinate Ry of approximately 0.290 that is constant, as the green color coordinate CC, an X-color coordinate Gx of approximately 0.210 that is constant for the green sub-pixel according to the data voltage level DVL and a Y-color coordinate Gy of approximately 0.710 that is constant, and as the blue color coordinate CC, an X-color coordinate Bx of approximately 0.135 that is constant for the blue sub-pixel according to the data voltage level DVL and a Y-color coordinate By of approximately 0.005 that is constant. Additionally, although Figure 8 an example where the red, green, and blue color coordinates CC are constant for the data voltage level DVL is shown, according to an embodiment, the data-RGB color coordinate information DAT_RGBCCI may include red, green, and blue color coordinates CC that change according to the data voltage level DVL. And, in one embodiment, as Figure 9As shown, the data-RGB luminance block 260 can store data-RGB luminance (or luminous efficiency) information DAT_RGBLI of red luminance (or luminous efficiency) 510 for the red sub-pixel, green luminance (or luminous efficiency) 530 for the green sub-pixel, and blue luminance (or luminous efficiency) 550 for the blue sub-pixel according to the data voltage level DVL. For example, the grayscale-voltage calculator 240 can determine the ratios of the red voltage level, green voltage level, and blue voltage level having the color coordinates represented by the target white color coordinate TGT_WCC at each grayscale based on the target white color coordinate TGT_WCC and the data-RGB color coordinate information DAT_RGBCCI, and can determine the red voltage level, the green voltage level, and the blue voltage level that maintain the ratios at each grayscale and have the luminance represented by the grayscale-luminance information GLI based on the grayscale-luminance information GLI and the data-RGB luminance information DAT_RGBLI.

[0074] The grayscale voltage generator 130 can read grayscale-voltage information GVI from the gamma block 210 and generate a plurality of grayscale voltages GV having the plurality of voltage levels represented by the grayscale-voltage information GVI (S440). The data driver 140 can supply a plurality of grayscale voltages GV corresponding to the output image data ODAT as data voltages DV to the plurality of pixels PX in the image display period (S450), and can supply a black data voltage to the plurality of pixels PX in the black insertion period (S460). Accordingly, even if the peak luminance PEAK_LUM is changed, the image displayed by the plurality of pixels PX in the image display period can have a luminance corresponding to the target gamma value TGT_GAMMA.

[0075] Figure 10 is a block diagram showing a display device for explaining another embodiment according to the present invention, Figure 11 is a block diagram showing an example of a controller included in a display device according to another embodiment of the present invention.

[0076] Referring to Figure 10 and Figure 11 , a display device 600 according to an embodiment of the present invention may include a display panel 110, a scan driver 120, a grayscale voltage generator 130, a data driver 140, and a controller 650. The controller 650 may include a data analyzer 660, a gamma controller 200, and a gamma block 210. Except that the controller 650 does not receive black insertion information BII from an external host and includes a data analyzer 660 that analyzes the input image data IDAT to generate black insertion information BII, Figure 10The display device 600 may have a configuration and operation similar to that of Figure 1 the display device 100.

[0077] The data analyzer 660 may analyze the input image data IDAT to determine a black duty ratio that is the ratio of the black image interval to the frame interval or the sum of the image display interval and the black image interval, and may generate black insertion information BII representing the black duty ratio. In one embodiment, the data analyzer 660 may analyze the dynamic amount and / or data load of the input image data IDAT to determine the black duty ratio. For example, the data analyzer 660 may increase the black duty ratio as the dynamic amount of the input image data IDAT increases.

[0078] The peak brightness calculator 220 may receive the black insertion information BII from the data analyzer 660, and determine the peak brightness PEAK_LUM based on the black duty ratio represented by the black insertion information BII and the target brightness TGT_LUM. The gray-scale - brightness calculator 230 may determine gray-scale - brightness information GLI based on the peak brightness PEAK_LUM and the target gamma value TGT_GAMMA. The gray-scale - voltage calculator 240 may generate gray-scale - voltage information GVI based on the target white color coordinate TGT_WCC, the gray-scale - brightness information GLI, the data - RGB color coordinate information DAT_RGBCCI, and the data - RGB brightness information DAT_RGBLI. The gray-scale voltage generator 130 may generate a plurality of gray-scale voltages GV based on the gray-scale - voltage information GVI. Accordingly, even if the peak brightness PEAK_LUM is changed, the display device 600 according to an embodiment of the present invention may have a certain gamma characteristic, that is, a gamma characteristic having a certain target gamma value TGT_GAMMA.

[0079] Figure 12 is a sequence diagram showing a driving method of a display device according to another embodiment of the present invention.

[0080] Referring to Figure 10 、 Figure 11 and Figure 12 , in a driving method of a display device 100 including a plurality of pixels PX, the data analyzer 660 may analyze the input image data IDAT to determine a black duty ratio that is the ratio of the black image interval to the frame interval or the sum of the image display interval and the black image interval, and generate black insertion information BII representing the black duty ratio (S700).

[0081] The peak brightness calculator 220 may receive black insertion information BII from the data analyzer 660, and determine the peak brightness PEAK_LUM based on the black duty ratio represented by the black insertion information and the target brightness TGT_LUM (S710). The gray-scale brightness calculator 230 may determine gray-scale brightness information GLI based on the peak brightness PEAK_LUM and the target gamma value TGT_GAMMA (S720). The gray-scale voltage calculator 240 may generate gray-scale voltage information GVI based on the target white color coordinate TGT_WCC, the gray-scale brightness information GLI, the data-RGB color coordinate information DAT_RGBCCI, and the data-RGB brightness information DAT_RGBLI (S730). The gray-scale voltage generator 130 may generate a plurality of gray-scale voltages GV based on the gray-scale voltage information GVI (S740). The data driver 140 may provide the plurality of gray-scale voltages GV corresponding to the output image data ODAT as data voltages DV to the plurality of pixels PX during the image display period (S750), and provide black data voltages to the plurality of pixels PX during the black insertion period (S760). Accordingly, even if the peak brightness PEAK_LUM is changed, the image displayed by the plurality of pixels PX during the image display period may have a brightness corresponding to the target gamma value TGT_GAMMA.

[0082] Figure 13 is a block diagram of an electronic device including a display device according to an embodiment of the present invention.

[0083] Referring to Figure 13 , the electronic device 1100 may include a processor 1110, a memory device 1120, a storage device 1130, an input / output device 1140, a power supply 1150, and a display device 1160. The electronic device 1100 may further include a plurality of ports capable of communicating with a graphics card, a sound card, a memory card, a USB device, etc., or communicating with other systems.

[0084] The processor 1110 may perform specific calculations or tasks. According to an embodiment, the processor 1110 may be a microprocessor, a central processing unit (CPU), etc. The processor 1110 may be connected to other components through an address bus, a control bus, a data bus, etc. According to an embodiment, the processor 1110 may also be connected to an expansion bus such as a peripheral component interconnect (PCI) bus.

[0085] The memory device 1120 can store data required for the operation of the electronic device 1100. For example, the memory device 1120 can include non-volatile storage devices such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, phase change random access memory (PRAM), resistance random access memory (RRAM), nano floating gate memory (NFGM), polymer random access memory (PoRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), etc., and / or volatile storage devices such as dynamic random access memory (DRAM), static random access memory (SRAM), mobile DRAM, etc.

[0086] The storage device 1130 can include a solid state drive (SSD), a hard disk drive (HDD), a CD-ROM, etc. The input / output device 1140 can include an input unit such as a keyboard, a keypad, a touchpad, a touch screen, a mouse, etc., and an output unit such as a speaker, a printer, etc. The power supply 1150 can supply the power required for the operation of the electronic device 1100. The display device 1160 can be connected to other components through the bus or other communication links.

[0087] The display device 1160 may determine the peak brightness based on the black duty ratio and the target brightness, determine grayscale-brightness information based on the peak brightness and the target gamma value, generate grayscale-voltage information based on the target white color coordinates and the grayscale-brightness information, and generate a plurality of grayscale voltages based on the grayscale-voltage information. Accordingly, even if the peak brightness is changed, the display device 1160 according to an embodiment of the present invention may have a certain gamma characteristic, that is, a gamma characteristic of a certain target gamma value.

[0088] According to an embodiment, the electronic device 1100 may be any electronic device including the display device 1160 such as a mobile phone, a smart phone, a tablet computer, a virtual reality (VR) device, a digital TV, a 3D TV, a personal computer (PC), a home electronic device, a laptop computer, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital camera, a music player, a portable game console, a navigation device, etc.

[0089] Industrial Applicability

[0090] The present invention can be applied to any display device and an electronic device including the same. For example, the present invention can be applied to a mobile phone, a smart phone, a tablet computer, a VR device, a digital TV, a 3D TV, a PC, a home electronic device, a laptop computer, a PDA, a PMP, a digital camera, a music player, a portable game console, a navigation device, etc.

[0091] Although the above has been described with reference to embodiments of the present invention, those skilled in the art can understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the claims.

Claims

1. A display device, comprising: A display panel including a plurality of pixels; A controller that determines a peak brightness based on a black duty ratio which is a ratio of a black insertion period to a sum of an image display period and the black insertion period, and a target brightness, and determines gray-scale - brightness information representing a plurality of brightness levels corresponding to a plurality of gray scales based on the peak brightness and a target gamma value, and generates gray-scale - voltage information representing a plurality of voltage levels corresponding to the plurality of gray scales based on a target white color coordinate and the gray-scale - brightness information; A gray-scale voltage generator that generates a plurality of gray-scale voltages having the plurality of voltage levels based on the gray-scale - voltage information; And A data driver that provides, during the image display period, a gray-scale voltage corresponding to output image data among the plurality of gray-scale voltages to the plurality of pixels as a data voltage, and provides a black data voltage to the plurality of pixels during the black insertion period, wherein the controller calculates the peak brightness using the following mathematical formula: PEAK_LUM = TGT_LUM / (1 - BDR), where PEAK_LUM represents the peak brightness, TGT_LUM represents the target brightness, and BDR represents the black duty ratio.

2. The display device according to claim 1, wherein The plurality of pixels display an image at a brightness corresponding to the target gamma value during the image display period.

3. The display device according to claim 1, wherein The controller includes: A peak brightness calculator that determines the peak brightness based on the black duty ratio and the target brightness; A gray-scale - brightness calculator that determines the gray-scale - brightness information based on the peak brightness and the target gamma value; A gray-scale - voltage calculator that generates the gray-scale - voltage information based on the target white color coordinate and the gray-scale - brightness information; and A gamma block that stores the gray-scale - voltage information.

4. The display device according to claim 3, wherein The peak brightness calculator receives black insertion information representing the black duty ratio from an external host.

5. The display device according to claim 3, wherein The controller further includes: A data analyzer that analyzes input image data to determine the black duty ratio and generates black insertion information representing the black duty ratio, and the peak brightness calculator receives the black insertion information from the data analyzer.

6. The display device according to claim 3, wherein The gray-scale - brightness calculator calculates the plurality of brightness levels corresponding to the plurality of gray scales using the following mathematical formula: GRAY_LUM = PEAK_LUM * (GRAY / MAX_GRAY)^TGT_GAMMA, where GRAY_LUM represents the brightness, PEAK_LUM represents the peak brightness, GRAY represents the gray scale, MAX_GRAY represents the maximum gray scale, and TGT_GAMMA represents the target gamma value.

7. A driving method for a display device, the driving method being for a display device including a plurality of pixels, comprising the following steps: Determining a peak brightness based on a black duty ratio, which is a ratio of a black insertion period to a sum of an image display period and the black insertion period, and a target brightness; Determining gray-scale - brightness information representing a plurality of brightnesses corresponding to a plurality of gray-scales based on the peak brightness and a target gamma value; Generating gray-scale - voltage information representing a plurality of voltage levels corresponding to the plurality of gray-scales based on a target white color coordinate and the gray-scale - brightness information; Generating a plurality of gray-scale voltages having the plurality of voltage levels based on the gray-scale - voltage information; Providing, during the image display period, a gray-scale voltage corresponding to output image data among the plurality of gray-scale voltages to the plurality of pixels as a data voltage; And Providing a black data voltage to the plurality of pixels during the black insertion period, wherein the step of determining the peak brightness based on the black duty ratio and the target brightness includes the following steps: Calculating the peak brightness using the following mathematical formula: PEAK_LUM = TGT_LUM / (1 - BDR), where PEAK_LUM represents the peak brightness, TGT_LUM represents the target brightness, and BDR represents the black duty ratio.

8. The driving method for a display device according to claim 7, wherein An image displayed through the plurality of pixels during the image display period has a brightness corresponding to the target gamma value.

Images