Display device and driving method thereof

Abstract

A display device and a driving method thereof are provided. The display device includes: a plurality of pixels receiving a data voltage based on a conversion grayscale; and a grayscale converter that calculates a first compensation offset based on positions of the plurality of pixels and an input grayscale for the plurality of pixels, converts the first compensation offset into a second compensation offset according to a maximum brightness weight based on an input maximum brightness, and calculates a conversion grayscale by applying the second compensation offset to the input grayscale.

Description

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0017200 filed on February 12, 2020, in the Korean Intellectual Property Office, and Korean Patent Application No. 10-2020-0118662 filed on September 15, 2020, in the Korean Intellectual Property Office, the disclosure of each of which is incorporated herein by reference in its entirety. Technical Field

[0002] Aspects of example embodiments of the present disclosure generally relate to a display device and a method of driving the display device. Background Art

[0003] As information technology develops, the importance of display devices as a connection medium between users and information increases. Therefore, for example, display devices such as liquid crystal display devices, organic light emitting display devices, and plasma display devices are increasingly used.

[0004] The display device may include a plurality of pixels, and the pixels may use at least one common power voltage. The voltage drop amount (eg, IR drop amount) of the power voltage of each pixel may differ from one another depending on the position and grayscale value of the pixel.

[0005] Therefore, various structures and methods for compensating for this voltage drop have been discussed. However, there is a trade-off between power consumption and display quality due to the compensation for the voltage drop.

[0006] The above information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute prior art. Summary of the Invention

[0007] One or more exemplary embodiments of the present disclosure are directed to providing a display device capable of improving display quality and reducing power consumption while compensating for a voltage drop amount of a power voltage by using at least one of an input maximum brightness and an on-pixel ratio, and a driving method of the display device.

[0008] According to one or more example embodiments of the present disclosure, a display device includes: a plurality of pixels configured to receive a data voltage based on a conversion grayscale; and a grayscale converter configured to calculate a first compensation offset based on positions of the plurality of pixels and an input grayscale for the plurality of pixels, convert the first compensation offset into a second compensation offset according to a maximum brightness weight based on an input maximum brightness, and calculate the conversion grayscale by applying the second compensation offset to the input grayscale.

[0009] In example embodiments, when the input maximum brightness is less than a first threshold, the maximum brightness weight may increase as the input maximum brightness increases, and when the input maximum brightness is greater than the first threshold, the maximum brightness weight may decrease as the input maximum brightness increases.

[0010] In an example embodiment, when the input maximum brightness is greater than a first threshold and less than a second threshold that is greater than the first threshold, the maximum brightness weight may correspond to a positive number; when the input maximum brightness corresponds to the second threshold, the maximum brightness weight may correspond to 0; and when the input maximum brightness is greater than the second threshold, the maximum brightness weight may correspond to a negative number.

[0011] In an example embodiment, the grayscale converter may include: a first lookup table including positions of the plurality of pixels and voltage drop amounts for a reference grayscale for the plurality of pixels; a voltage drop amount calculator configured to calculate the voltage drop amount of the input grayscale based on the first lookup table and the input grayscale; and a compensation offset calculator configured to calculate a first compensation offset corresponding to the voltage drop amount of the input grayscale.

[0012] In an example embodiment, the grayscale converter may further include: a maximum brightness weight provider configured to provide a maximum brightness weight corresponding to the input maximum brightness; a compensation offset converter configured to provide a second compensation offset by converting the first compensation offset according to the maximum brightness weight; and a conversion grayscale calculator configured to calculate a conversion grayscale by applying the second compensation offset to the input grayscale.

[0013] In example embodiments, the grayscale converter may further include a maximum brightness converter configured to provide the maximum brightness weight provider with a converted input maximum brightness converted based on the input grayscale and the input maximum brightness.

[0014] In an example embodiment, a maximum brightness converter may include: a target pattern detector configured to provide a pattern detection signal when a turn-on pixel ratio of an input grayscale is less than a reference ratio; a target brightness detector configured to provide a brightness detection signal when the input maximum brightness is within a reference brightness range; and a maximum brightness shifter configured to provide a converted input maximum brightness by converting the input maximum brightness when receiving the pattern detection signal and the brightness detection signal.

[0015] In example embodiments, the maximum brightness shifter may be configured to provide a conversion input maximum brightness by gradually increasing the input maximum brightness according to time.

[0016] In example embodiments, the maximum brightness converter may further include a frame counter configured to provide a count number by counting frames, and the maximum brightness shifter may be configured to provide the converted input maximum brightness by gradually increasing the input maximum brightness according to the count number.

[0017] In an example embodiment, the grayscale converter may further include a turn-on pixel weight provider configured to provide a turn-on pixel weight corresponding to the turn-on pixel ratio of the input grayscale, and the compensation offset converter may be configured to provide a second compensation offset by converting the first compensation offset according to the maximum brightness weight and the turn-on pixel weight.

[0018] In example embodiments, when the on-pixel ratio is less than a first threshold ratio, the on-pixel weight may increase as the on-pixel ratio increases.

[0019] In an example embodiment, when the on-pixel ratio is greater than a second threshold ratio that is greater than the first threshold ratio, the on-pixel weight may decrease as the on-pixel ratio increases, and when the on-pixel ratio is between the first threshold ratio and the second threshold ratio, the on-pixel weight may have a maximum value.

[0020] In example embodiments, the grayscale converter may further include an on-pixel ratio calculator configured to calculate the on-pixel ratio by applying a weight to an average value of the input grayscale for each color.

[0021] In example embodiments, the grayscale converter may further include a maximum brightness limiter configured to limit an increase in the second compensation offset when the on-pixel ratio decreases to a reference ratio or less.

[0022] According to one or more example embodiments of the present disclosure, a method for driving a display device includes: calculating a first compensation offset based on a position of a pixel and an input grayscale for the pixel; converting the first compensation offset into a second compensation offset according to a maximum brightness weight based on the input maximum brightness; calculating a converted grayscale by applying the second compensation offset to the input grayscale; and providing a data voltage to the pixel based on the converted grayscale.

[0023] In example embodiments, when the input maximum brightness is less than a first threshold, the maximum brightness weight may increase as the input maximum brightness increases, and when the input maximum brightness is greater than the first threshold, the maximum brightness weight may decrease as the input maximum brightness increases.

[0024] In an example embodiment, when the input maximum brightness is greater than a first threshold and less than a second threshold greater than the first threshold, the maximum brightness weight may correspond to a positive number, when the input maximum brightness corresponds to the second threshold, the maximum brightness weight may correspond to 0, and when the input maximum brightness is greater than the second threshold, the maximum brightness weight may correspond to a negative number.

[0025] In an example embodiment, the method may further include: generating a pattern detection signal when a ratio of on-pixels of an input grayscale is less than a reference ratio; generating a brightness detection signal when the input maximum brightness is within a reference brightness range; and converting the input maximum brightness when the pattern detection signal and the brightness detection signal are generated.

[0026] In an exemplary embodiment, in the step of converting the input maximum brightness, the converted input maximum brightness may be provided by gradually increasing the input maximum brightness according to time.

[0027] In an example embodiment, the method may further include providing a count number by counting frames, and in the converting the input maximum brightness, the converted input maximum brightness may be provided by gradually increasing the input maximum brightness according to the count number. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other aspects and features of the present disclosure will become more apparent to those skilled in the art from the following detailed description of example embodiments with reference to the accompanying drawings.

[0029] Figure 1 is a diagram illustrating a display device according to an embodiment of the present disclosure.

[0030] Figure 2 is a diagram illustrating pixels according to an embodiment of the present disclosure.

[0031] Figures 3 and 4 is a graph showing the brightness of a pattern according to frame data when the grayscale converter does not operate.

[0032] Figure 5 is a diagram illustrating a grayscale converter according to an embodiment of the present disclosure.

[0033] Figures 6 to 8 It shows that Figure 5 FIG2 is a diagram showing the brightness of a pattern according to frame data when the grayscale converter operates.

[0034] Figure 9 is a diagram illustrating an operation of a maximum luminance weight provider according to an embodiment of the present disclosure.

[0035] Figures 10 and 11 It shows that Figure 9The maximum brightness weight provider shown in FIG operates according to the brightness of the pattern of frame data.

[0036] Figure 12 is a diagram illustrating a grayscale converter according to another embodiment of the present disclosure.

[0037] Figures 13 and 14 is a diagram illustrating a maximum brightness converter according to an embodiment of the present disclosure.

[0038] Figures 15 and 16 is a diagram illustrating a maximum luminance converter according to another embodiment of the present disclosure.

[0039] Figure 17 is a diagram illustrating a grayscale converter according to another embodiment of the present disclosure.

[0040] Figure 18 is a diagram illustrating a turned-on pixel weight provider according to an embodiment of the present disclosure.

[0041] Figure 19 is a diagram illustrating a grayscale converter according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] Hereinafter, example embodiments will be described in more detail with reference to the accompanying drawings, in which like reference numerals always refer to like elements. However, the present disclosure may be implemented in a variety of different forms and should not be construed as being limited to the embodiments shown herein. On the contrary, these embodiments are provided as examples so that the present disclosure will be thorough and complete and will fully convey the aspects and features of the present disclosure to those skilled in the art. Therefore, processes, elements and techniques that are unnecessary for those of ordinary skill in the art to fully understand the aspects and features of the present disclosure may not be described. Unless otherwise stated, like reference numerals represent like elements throughout the drawings and written description, and therefore descriptions thereof may not be repeated.

[0043] In the accompanying drawings, for the sake of clarity, the relative size and / or thickness of elements, layers and regions may be exaggerated and / or simplified. For ease of explanation, spatial relative terms such as "under ... ", "below ... ", "below ... ", "below ... ", "above ... ", "above " can be used to describe the relationship between an element or feature and another (other) element or feature as shown in the figure. It will be understood that spatial relative terms are intended to include different orientations of the device in use or operation except for the orientation depicted in the figure. For example, if the device in the figure is flipped, the element or feature described as "under" or "under" or "below" other elements or features will then be positioned as "above" the other elements or features. Therefore, the example terms "under ... " and "below ... " can include both above and below orientations. The device can be positioned in addition (for example, rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0044] It will be understood that although the terms "first," "second," "third," etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Thus, a first element, first component, first region, first layer, or first part described below may be named a second element, second component, second region, second layer, or second part without departing from the spirit and scope of the present disclosure.

[0045] It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, the element or layer can be directly on, directly connected to, or directly coupled to the other element or layer, or one or more intervening elements or layers may be present. For example, when an electrode or wire is referred to as being “connected to” or “coupled to” another electrode or wire, the electrode or wire can be “directly” connected or coupled to the other electrode or wire, or it can be “indirectly” connected or coupled to the other electrode or wire with one or more intermediate electrodes or intermediate layers interposed therebetween. Additionally, it will be understood that when an element or layer is referred to as being “between” two elements or layers, the element or layer can be the only element or layer between the two elements or layers, or one or more intervening elements or intermediate layers may also be present.

[0046] The terms used herein are for the purpose of describing specific embodiments, and are not intended to be limitations of the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular "one" and "one (kind / person)" are also intended to include plural forms. It will also be understood that when the terms "comprises", "comprising" and "having" are used in this manual, the features, integral bodies, steps, operations, elements and / or components stated are described, but one or more other features, integral bodies, steps, operations, elements, components and / or their groups are not excluded from existence or addition. As used herein, the term "and / or" includes any combination and all combinations of one or more of the relevant listed items. When the expression such as "at least one (kind / person) in ... " is after a column of elements (elements), what is modified is the element (element) of the entire column, and the individual elements (element) in the column are not modified.

[0047] As used herein, the terms "substantially," "approximately," and similar terms are used as terms of approximation rather than terms of degree, and are intended to account for the inherent deviations in measurements or calculations that one of ordinary skill in the art would recognize. Furthermore, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure." As used herein, the term "using" and variations thereof may be considered synonymous with the term "utilizing" and variations thereof, respectively. Furthermore, the term "exemplary" is intended to mean an example or illustration.

[0048] The electronic or electrical devices and / or any other related devices or components according to the various embodiments of the present disclosure described herein (e.g., grayscale converter, voltage drop calculator, compensation offset calculator, compensation offset converter, conversion grayscale calculator, maximum brightness weight provider, maximum brightness converter, target pattern detector, target maximum brightness detector, maximum brightness shifter, frame counter, on-pixel weight provider, on-pixel ratio calculator, maximum brightness limiter, etc.) can be implemented using any suitable hardware, firmware (e.g., a dedicated integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of these devices can be formed on an integrated circuit (IC) chip or on separate IC chips. In addition, the various components of these devices can be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on a substrate. In addition, the various components of these devices can be processes or threads that run on one or more processors, execute computer program instructions in one or more computing devices, and interact with other system components to perform the various functions described herein. The computer program instructions are stored in a memory that can be implemented in a computing device using a standard memory device (such as, for example, a random access memory (RAM)). The computer program instructions may also be stored in other non-transitory computer-readable media, such as, for example, a CD-ROM, a flash drive, etc. In addition, those skilled in the art will recognize that, without departing from the spirit and scope of the exemplary embodiments of the present disclosure, the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices.

[0049] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will also be understood that terms (such as those defined in common dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an idealized or overly formal sense, unless expressly defined as such herein.

[0050] Figure 1 is a diagram illustrating a display device according to an embodiment of the present disclosure.

[0051] Reference Figure 1 , a display device 10 according to one or more embodiments of the present disclosure may include a timing controller 11 , a data driver 12 , a scan driver 13 , a pixel unit (eg, a pixel panel or a pixel layer) 14 , and a grayscale converter 15 .

[0052] The timing controller 11 may receive input grayscale and control signals for each frame from an external processor. The input grayscale for a frame may be referred to as frame data. For the purpose of frame display, the timing controller 11 may provide appropriate control signals to the data driver 12, the scan driver 13, etc. according to their specifications.

[0053] The grayscale converter 15 may provide a converted grayscale obtained by converting an input grayscale. The timing controller 11 may provide the converted grayscale to the data driver 12. The grayscale converter 15 may be configured as an integrated chip (IC) integrated with the timing controller 11, or may be configured as a separate IC. In some embodiments, the grayscale converter 15 may be implemented as software in the timing controller 11.

[0054] The data driver 12 may generate data voltages to be supplied to the data lines DL1, DL2, DL3, ..., and DLn by using the conversion grayscale and the control signal, where n may be an integer greater than 0. For example, the data driver 12 may sample the conversion grayscale using a clock signal and apply the data voltage corresponding to the conversion grayscale to the data lines DL1 to DLn in units of pixel rows. A pixel row may refer to a group of pixels connected to one scan line (e.g., a group of pixels connected to the same scan line).

[0055] The scan driver 13 may generate scan signals to be provided to the scan lines SL1 , SL2 , SL3 , . . . , and SLm by receiving a clock signal and / or a scan start signal, etc., from the timing controller 11 , where m may be an integer greater than 0.

[0056] The scan driver 13 may sequentially supply a scan signal having an on-level pulse to the scan lines SL1 to SLm. The scan driver 13 may be configured in the form of a shift register and may include a plurality of scan stages. For example, the scan driver 13 may generate a scan signal by sequentially transmitting a scan start signal in the form of an on-level pulse to the next scan stage under the control of a clock signal.

[0057] The pixel unit 14 includes a plurality of pixels. Each pixel can be connected to a corresponding data line and a corresponding scan line. For example, the ijth pixel PXij (where i and j can be integers greater than 0) can refer to a pixel in which its scan transistor is connected to the i-th scan line and the j-th data line. The pixels can be commonly connected to a first power line ELVDDL and a second power line ELVSSL (for example, see Figure 2 ).

[0058] Figure 2 is a diagram illustrating pixels according to an embodiment of the present disclosure.

[0059] Reference Figure 2 , the pixel PXij may be a pixel for emitting light of a first color. Other pixels (e.g., pixels for emitting light of a second color or a third color) may include components that are the same or substantially the same as those of the pixel PXij, except for the color emitted by its light emitting diode LD, and therefore, a redundant description thereof may not be repeated.

[0060] For example, in some embodiments, the first color may be one of red, green, and blue, the second color may be another color of red, green, and blue that is different from the first color, and the third color may be another color of red, green, and blue that is different from the first and second colors. In other embodiments, instead of red, green, and blue, the first to third colors may be any suitable colors of magenta, cyan, and yellow.

[0061] The pixel PXij may include a plurality of transistors T1 and T2 (eg, first and second transistors T1 and T2 ), a storage capacitor Cst1 , and a light emitting diode LD.

[0062] Although Figure 2 The case where the transistors T1 and T2 are implemented as P-type transistors (such as, for example, PMOS transistors), is shown, but the present disclosure is not limited thereto, and a person skilled in the art may use other types of transistors (such as, for example, N-type transistors (e.g., NMOS transistors)) to design pixel circuits that perform the same or substantially the same functions.

[0063] A gate electrode of the transistor (e.g., the second transistor) T2 may be connected to the scan line SLi, a first electrode of the transistor T2 may be connected to the data line DLj, and a second electrode of the transistor T2 may be connected to the gate electrode of the transistor (e.g., the first transistor) T1. The transistor T2 may be referred to as a scan transistor, a switching transistor, etc.

[0064] A gate electrode of transistor (eg, first transistor) T1 may be connected to a second electrode of transistor T2, a first electrode of transistor T1 may be connected to the first power line ELVDDL, and a second electrode of transistor T1 may be connected to an anode of light emitting diode LD. Transistor T1 may be referred to as a driving transistor.

[0065] The storage capacitor Cst1 connects the first electrode of the transistor T1 and the gate electrode of the transistor T1 to each other.

[0066] The anode of the light emitting diode LD may be connected to the second electrode of the transistor T1, and the cathode of the light emitting diode LD may be connected to the second power line ELVSSL. The light emitting diode LD may be an element for emitting light having a wavelength corresponding to the first color. The light emitting diode LD may be configured as an organic light emitting diode, an inorganic light emitting diode, a quantum dot / well light emitting diode, etc. Although in Figure 2 Only one light emitting diode LD is shown in FIG. 1 , but the present disclosure is not limited thereto, and in some embodiments, a plurality of sub-light emitting diodes may be connected in series, in parallel, or in series and parallel to form the light emitting diode LD.

[0067] When a scan signal having a turn-on level (e.g., a low level) is supplied to the gate electrode of the transistor T2 through the scan line SLi, the transistor T2 connects the first electrode of the storage capacitor Cst1 to the data line DLj. Therefore, a voltage corresponding to a difference between a data voltage applied through the data line DLj and a first power voltage ELVDD applied through the first power line ELVDDL can be charged in the storage capacitor Cst1.

[0068] The transistor T1 allows a driving current determined according to a voltage charged in the storage capacitor Cst1 to flow from the first power line ELVDDL to the second power line ELVSSL via the light emitting diode LD. The light emitting diode LD emits light having a desired brightness corresponding to the amount of the driving current.

[0069] Figure 3 and Figure 4 is a graph showing the brightness of a pattern according to frame data when the grayscale converter does not operate.

[0070] Reference Figure 3 , the pixel unit 14 is exemplarily shown as being in the following state: a first pixel among the multiple pixels emits light corresponding to a white grayscale (e.g., a white grayscale value or a white grayscale), and a second pixel among the multiple pixels other than the first pixel does not emit light to correspond to a black grayscale (e.g., a black grayscale value or a black grayscale).

[0071] For example, a first input grayscale for a first pixel may correspond to a white grayscale, and a second input grayscale for a second pixel may correspond to a black grayscale.The first frame data may include the first input grayscale and the second input grayscale.

[0072] The ratio of the first pixel among the plurality of pixels may be referred to as an on-pixel ratio OPR. For example, the ratio of the number of pixels displaying white grayscale (e.g., the number of first pixels) among the total number of pixels may be 65%. In this case, the on-pixel ratio OPR of the first frame data may be 65%.

[0073] However, the present disclosure is not limited to the on-pixel ratio OPR determined by using only pixels displaying white grayscale and pixels displaying black grayscale. For example, the on-pixel ratio OPR may be defined as shown in the following equation 1.

[0074] Equation 1:

[0075] OPR(%)=((AVG_R×WR+AVG_G×WG+AVG_B×WB) / MG)×100

[0076] In Equation 1, AVG_R may correspond to the average value of red grayscale in the first frame data, WR may correspond to the first weight, AVG_G may correspond to the average value of green grayscale in the first frame data, WG may correspond to the second weight, AVG_B may correspond to the average value of blue grayscale in the first frame data, WB may correspond to the third weight, and MG may correspond to the maximum grayscale value.

[0077] For example, each of the red grayscale values ​​may be one of values ​​from 0 to 255, each of the green grayscale values ​​may be one of values ​​from 0 to 255, and each of the blue grayscale values ​​may be one of values ​​from 0 to 255. In this case, MG may be 255.

[0078] Each of the first weight WR, the second weight WG, and the third weight WB can be set to 1 / 3. In another embodiment, each of the first weight WR, the second weight WG, and the third weight WB can correspond to the brightness contribution rate of the corresponding color. For example, the first weight WR can be set to 0.2, the second weight WG can be set to 0.7, and the third weight WB can be set to 0.1. In another embodiment, when an algorithm for minimizing or reducing power consumption is applied, the third weight WB corresponding to blue (e.g., blue color or blue grayscale) can be set to the highest. The sum of the first weight WR, the second weight WG, and the third weight WB can be 1.

[0079] According to the above-described Equation 1, the on-pixel ratio OPR may be calculated for various types (eg, all types) of frame data.

[0080] Before the display device 10 is shipped, a tuning process may be performed on the display device 10 to compensate for process variations and signal differences based on pixel positions. If this tuning process is not performed, speckles may be observed in the image. It has been found that the on-pixel ratio (OPR) of frame data most commonly viewed by users when using the display device 10 is approximately 65%. Therefore, in some embodiments, the display device 10 may be shipped after the tuning process is performed using frame data having an on-pixel ratio (OPR) of 65%.

[0081] Due to takt time limitations, the input maximum brightness used in the tuning process may correspond to some of the input maximum brightness that can be used by the user.

[0082] The input maximum brightness may be the brightness value of light emitted from a pixel corresponding to a maximum grayscale (e.g., a maximum grayscale value or a maximum grayscale). For example, the input maximum brightness may be the brightness of white light generated when the pixels of the pixel unit 14 (e.g., all pixels in the pixel unit 14) emit light corresponding to a white grayscale. The unit of brightness may be expressed in nits. The input maximum brightness may be referred to as a display brightness value DBV.

[0083] The pixel unit 14 can display a locally (e.g., spatially) dark or bright image, but the maximum brightness of the image is limited to the input maximum brightness. The input maximum brightness can be manually set by a user operation or automatically set by an algorithm associated with a brightness sensor or the like.

[0084] Although the value of the input maximum brightness may vary depending on the implementation (e.g., product), in some embodiments, the maximum value of the input maximum brightness may be, for example, 1200 nits, and the minimum value of the input maximum brightness may be, for example, 4 nits. Because the data voltage for some grayscales (e.g., for a specific grayscale) may vary (e.g., may vary) according to the input maximum brightness, the emission brightness of the pixel may also vary (e.g., may also vary).

[0085] exist Figure 3 In the embodiment, it is assumed that the maximum input brightness is 1200 nits. Therefore, in this case, when the on-pixel ratio OPR is 65% and the maximum input brightness is 1200 nits, the user can view the image of the first frame data that is optimally tuned in the display device 10.

[0086] Reference Figure 4 , the pixel unit 14 is exemplarily shown as being in the following state: the second pixel in addition to the first pixel also emits light corresponding to the white grayscale. For example, the first input grayscale for the first pixel may correspond to the white grayscale, and the second input grayscale for the second pixel may correspond to the white grayscale. In other words, in Figure 4 In the example, the on-pixel ratio OPR may be 100%.

[0087] Although the input maximum brightness is 1200 nits, the pixel unit 14 displays an image of 1000 nits. This situation occurs when the IR drop of the power voltages ELVDD and ELVSS increases according to the increase in the on-pixel ratio OPR (for example, the increase in the load). Therefore, although the user can set the input maximum brightness to 1200 nits, the maximum brightness actually displayed in the image will change according to the on-pixel ratio OPR of the frame data (for example, it will change according to the on-pixel ratio OPR of the frame data). For example, as the on-pixel ratio OPR becomes greater than 65%, the maximum brightness displayed in the image will become less than 1200 nits. In addition, for example, as the on-pixel ratio OPR becomes less than 65%, the maximum brightness displayed in the image will become greater than 1200 nits. Therefore, although the user can set the input maximum brightness (for example, the same input maximum brightness), the user will view images with different maximum brightness (for example, unequal maximum brightness) according to the on-pixel ratio OPR (for example, according to the load).

[0088] Figure 5 is a diagram illustrating a grayscale converter according to an embodiment of the present disclosure. Figures 6 to 8 It shows that Figure 5 FIG2 is a diagram showing the brightness of a pattern according to frame data when the grayscale converter operates.

[0089] Reference Figure 5 The grayscale converter 15a according to one or more example embodiments of the present disclosure may include a voltage drop amount calculator 151, a compensation offset calculator 152, a compensation offset converter 153, a conversion grayscale calculator 154, a first lookup table 155, and a maximum brightness weight provider 156.

[0090] The grayscale converter 15a may calculate a first compensation offset COFS based on the pixel position and the input grayscale GVi for the pixel, convert the first compensation offset COFS into a second compensation offset COFSm, and calculate a conversion grayscale GVo by applying the second compensation offset COFSm to the input grayscale GVi. The grayscale converter 15a may convert the first compensation offset COFS into the second compensation offset COFSm based on the maximum brightness weight Wdbv based on the input maximum brightness DBVi. The pixel may receive a data voltage based on the conversion grayscale GVo.

[0091] The first lookup table 155 may include the pixel location and the voltage drop amount IRDr of the reference grayscale for the pixel. The voltage drop amount IRDr of the reference grayscale may correspond to the IR drop amount. The first lookup table 155 may be implemented using a memory or other suitable storage medium. As described above, due to takt time limitations, organizing the first lookup table 155 corresponding to all input maximum luminances DBVi and all input grayscales GVi may be inefficient. Therefore, the first lookup table 155 may be organized based on reference grayscales corresponding to some of the available input grayscales GVi and reference input maximum luminances corresponding to some of the available input maximum luminances DBVi.

[0092] The voltage drop amount calculator 151 may calculate the voltage drop amount IRD of the input grayscale GVi with reference to the first lookup table 155 and the input grayscale GVi. The voltage drop amount calculator 151 may calculate the voltage drop amount IRD based on a difference between the input grayscale GVi and a reference grayscale.

[0093] In another embodiment, the voltage drop calculator 151 may also receive the input maximum brightness DBVi. In this case, in addition to the difference between the input grayscale GVi and the reference grayscale, the voltage drop calculator 151 may also calculate the voltage drop IRD based on the difference between the input maximum brightness DBVi and the reference input maximum brightness.

[0094] The compensation offset calculator 152 may calculate a first compensation offset COFS corresponding to the voltage drop amount IRD. For example, the first compensation offset COFS may increase as the voltage drop amount IRD increases. According to an embodiment, when the on-pixel ratio OPR of the frame data is greater than a reference on-pixel ratio (e.g., 65%), the first compensation offset COFS may correspond to a positive number. Furthermore, when the on-pixel ratio OPR of the frame data is less than the reference on-pixel ratio, the first compensation offset COFS may correspond to a negative number.

[0095] The maximum brightness weight provider 156 may provide a maximum brightness weight Wdbv corresponding to the input maximum brightness DBVi. The maximum brightness weight provider 156 may increase the maximum brightness weight Wdbv as the input maximum brightness DBVi increases.

[0096] Reference Figure 6, the reference maximum brightness weight Wdbvt can be set to 1, and the reference maximum brightness weight Wdbvt enables the pixel unit 14 to present the reference brightness Nitst with the reference input maximum brightness DBVt at the tuning time. The on-pixel ratio OPR at the tuning time can be referred to as the reference on-pixel ratio (e.g., 65%). For example, when the input maximum brightness DBVi is greater than the reference input maximum brightness DBVt, the maximum brightness weight provider 156a can provide a maximum brightness weight Wdbv greater than 1. When the input maximum brightness DBVi is less than the reference input maximum brightness DBVt, the maximum brightness weight provider 156a can provide a maximum brightness weight Wdbv less than 1.

[0097] The compensation offset converter 153 can provide the second compensation offset COFSm by converting the first compensation offset COFS according to the maximum brightness weight Wdbv. For example, the compensation offset converter 153 can provide the second compensation offset COFSm by multiplying the first compensation offset COFS by the corresponding maximum brightness weight Wdbv. Therefore, when the input maximum brightness DBVi is equal to the reference input maximum brightness DBVt, the first compensation offset COFS and the second compensation offset COFSm can be the same or substantially the same as each other. When the input maximum brightness DBVi is greater than the reference input maximum brightness DBVt, the absolute value of the second compensation offset COFSm can be greater than the absolute value of the first compensation offset COFS. When the input maximum brightness DBVi is less than the reference input maximum brightness DBVt, the absolute value of the second compensation offset COFSm can be less than the absolute value of the first compensation offset COFS.

[0098] The conversion grayscale calculator 154 may calculate the conversion grayscale GVo by applying the second compensation offset COFSm to the input grayscale GVi. For example, the conversion grayscale calculator 154 may calculate the conversion grayscale GVo for each pixel by adding the input grayscale GVi to the corresponding second compensation offset COFSm.

[0099] Figure 7 and Figure 8 It shows that Figure 5 FIG2 is a diagram showing the brightness of a pattern according to frame data when the grayscale converter operates.

[0100] Reference Figure 7 , even when the on-pixel ratio OPR of the frame data is 100%, the pixel unit 14 can display an image with a brightness of 1200 nits. In other words, because the on-pixel ratio OPR is greater than the reference on-pixel ratio (e.g., 65%), the first compensation offset COFS and the second compensation offset COFSm can correspond to positive numbers, and the conversion grayscale GVo can be greater than the input grayscale GVi.

[0101] Reference Figure 8 , even when the on-pixel ratio OPR of the frame data is 10%, the pixel unit 14 can display an image with a brightness of 1200 nits. In other words, because the on-pixel ratio OPR is less than the reference on-pixel ratio (e.g., 65%), the first compensation offset COFS and the second compensation offset COFSm may correspond to negative numbers, and the conversion grayscale GVo may be less than the input grayscale GVi.

[0102] According to one or more exemplary embodiments of the present disclosure, Figure 3 and Figure 4 Unlike the situation shown in , when the user sets the input maximum brightness (e.g., the same input maximum brightness), the user can view an image with the same or substantially the same maximum brightness (e.g., equal or substantially equal maximum brightness) even when the on-pixel ratio OPR (e.g., load) changes.

[0103] like Figure 7 As shown in FIG, when the on-pixel ratio OPR is 100%, in order for the pixel unit 14 to display an image with 1200 nits, the difference between the first power voltage ELVDD and the second power voltage ELVSS is large (e.g., very large). However, it is difficult to set the second power voltage ELVSS sufficiently low and / or to set the first power voltage ELVDD sufficiently high.

[0104] Figure 9 is a diagram illustrating an operation of a maximum luminance weight provider according to an embodiment of the present disclosure.

[0105] When the input maximum brightness DBVi is less than the first threshold DBVc1, the maximum brightness weight provider 156d according to one or more embodiments of the present disclosure may increase the maximum brightness weight Wdbv as the input maximum brightness DBVi increases. In addition, when the input maximum brightness DBVi is greater than the first threshold DBVc1, the maximum brightness weight provider 156d may decrease the maximum brightness weight Wdbv as the input maximum brightness DBVi increases.

[0106] Furthermore, when the input maximum brightness DBVi is greater than the first threshold DBVc1 and less than the second threshold DBVc2, the maximum brightness weight Wdbv may correspond to a positive number. When the input maximum brightness DBVi corresponds to (e.g., is equal to or substantially equal to) the second threshold DBVc2, the maximum brightness weight Wdbv may correspond to (e.g., may be equal to or substantially equal to) 0. Furthermore, when the input maximum brightness DBVi is greater than the second threshold DBVc2, the maximum brightness weight Wdbv may correspond to a negative number. The second threshold DBVc2 may be greater than the first threshold DBVc1.

[0107] Figure 10 and Figure 11 It shows that Figure 9 The maximum brightness weight provider shown in FIG operates according to the brightness of the pattern of frame data.

[0108] According to the reference Figure 9 The described maximum brightness weight provider 156d allows the user to view an image having a uniform or substantially uniform maximum brightness even when the on-pixel ratio OPR changes, when the input maximum brightness DBVi set by the user is less than the first threshold DBVc1.

[0109] For example, when the pixels (e.g., all pixels) of the pixel unit 14 are configured to have a first pixel and a second pixel other than the first pixel, the first frame data may include a first input grayscale for the first pixel and a second input grayscale for the second pixel. The first input grayscale may correspond to a white grayscale (e.g., a white grayscale value or a white grayscale), and the second input grayscale may correspond to a black grayscale (e.g., a black grayscale value or a black grayscale). The on-pixel ratio OPR of the first frame data may be referred to as a first ratio. Assume that the input maximum brightness DBVi has a first value less than a first threshold DBVc1. The brightness of the light emitted from the first pixel is assumed to be the first brightness.

[0110] For example, the second frame data may include a first input grayscale for the first pixel and a second input grayscale for the second pixel. The first input grayscale may correspond to a white grayscale, some of the second input grayscales may correspond to a white grayscale, and others of the second input grayscales may correspond to a black grayscale. The on-pixel ratio OPR of the second frame data may be referred to as a second ratio. In other words, the second ratio of the second frame data may be greater than the first ratio of the first frame data. Assume that the input maximum brightness DBVi has a first value. The brightness of the light emitted from the first pixel may be a second brightness that is equal to or substantially equal to the first brightness. In addition, the brightness of the light corresponding to the white grayscale emitted from the second pixel may be the second brightness. In other words, when the input maximum brightness DBVi is less than the first threshold DBVc1, the image may have a uniform or substantially uniform maximum brightness regardless of the on-pixel ratio OPR.

[0111] according to Figure 9 According to the maximum brightness weight provider 156d shown in FIG, when the input maximum brightness set by the user is greater than the first threshold DBVc1, the user can view images with various maximum brightnesses according to the on-pixel ratio OPR.

[0112] For example, when the first frame data is input to the display device 10, the input maximum brightness DBVi has the second value instead of the first value and the on-pixel ratio OPR is the first ratio, the first pixel may emit light having a third brightness (eg, Figure 11The second value may be greater than the first value. For example, the second value may be greater than the first threshold DBVc1.

[0113] For example, when the second frame data is input to the display device 10, the input maximum brightness DBVi has a second value and the on-pixel ratio OPR is a second ratio, the first pixel may emit light having a fourth brightness (e.g., 800 nits) lower than the third brightness (e.g., see FIG. Figure 10 ). The second ratio may be greater than the first ratio.

[0114] According to this embodiment, for a high input maximum brightness DBVi, power consumption can be reduced at a high on-pixel ratio OPR (see, for example, Figure 10 ), and can increase the maximum brightness at low on-pixel ratio OPR (see, for example, Figure 11 The increase in maximum brightness allows for contrast (e.g., extreme contrast) between dark and bright areas of the display, and thus, may be desirable for high dynamic range (HDR) technology. Thus, the increase in maximum brightness may be useful for image effects such as, for example, stars shining in the night sky.

[0115] When the input maximum brightness DBVi is greater than the first threshold DBVc1, as shown in FIG. Figure 7 As described above, due to the hardware limitations and / or other limitations of the display device 10, it is difficult to provide an image with uniform or substantially uniform maximum brightness regardless of the on-pixel ratio OPR. Therefore, it may be more desirable to Figure 10 and Figure 11 The effect shown in .

[0116] exist Figure 10 In the example, because the first compensation offset COFS corresponds to a positive number, the second compensation offset COFSm, obtained by multiplying the maximum luminance weight Wdbv, which corresponds to a negative number, becomes a negative number. Therefore, the converted grayscale GVo can become smaller than the input grayscale GVi. For example, when the input maximum luminance DBVi corresponds to 1200 nits as the maximum value DBVma and the on-pixel ratio OPR is 100%, the image can have a maximum luminance of 800 nits.

[0117] exist Figure 11 In the example, because the first compensation offset COFS corresponds to a negative number, the second compensation offset COFSm, multiplied by the negative maximum luminance weight Wdbv, becomes a positive number. As a result, the converted grayscale GVo can become greater than the input grayscale GVi. For example, when the input maximum luminance DBVi corresponds to the maximum value DBVma and the on-pixel ratio OPR is 10%, the image can have a maximum luminance of 1800 nits.

[0118] Figure 12is a diagram illustrating a grayscale converter according to another embodiment of the present disclosure.

[0119] Figure 12 The grayscale converter 15b shown in FIG can be used with Figure 5 The grayscale converter 15a shown in FIG is different in that: Figure 12 The grayscale converter 15b further includes a maximum luminance converter 157. Therefore, differences therebetween may be mainly described hereinafter, and redundant descriptions of the same or substantially the same components thereof may not be repeated.

[0120] The maximum brightness converter 157 may provide the conversion input maximum brightness DBVo to the maximum brightness weight provider 156 , and the conversion input maximum brightness DBVo may be converted based on the input grayscale GVi and the input maximum brightness DBVi.

[0121] Figure 13 and Figure 14 is a diagram illustrating a maximum brightness converter according to an embodiment of the present disclosure.

[0122] Reference Figure 13 , the maximum brightness converter 157 a according to one or more embodiments of the present disclosure may include a target maximum brightness detector 1571 , a target pattern detector 1572 , and a maximum brightness shifter 1573 .

[0123] When the input maximum brightness DBVi belongs to the reference brightness range DBVr (eg, has a value within the reference brightness range DBVr), the target maximum brightness detector 1571 may provide a brightness detection signal TDBV. For example, the reference brightness range DBVr may be less than the first threshold DBVc1.

[0124] When the on-pixel ratio OPR of the input grayscale GVi is less than a reference ratio, the target pattern detector 1572 may provide a pattern detection signal TPAT.

[0125] When the maximum brightness shifter 1573 receives the pattern detection signal TPAT and the brightness detection signal TDBV, the maximum brightness shifter 1573 may provide a converted input maximum brightness DBVo by converting the input maximum brightness DBVi.

[0126] In other words, according to the target maximum brightness detector 1571 and the target pattern detector 1572, frame data for contrast emphasis, such as, for example, stars twinkling in the night sky, can be detected. For frame data, even when the input maximum brightness DBVi is less than the first threshold DBVc1, the input maximum brightness DBVi is increased, thereby achieving and presenting the image according to the maximum brightness detector 1571 and the target pattern detector 1572. Figure 9 and Figure 11 The effect of the embodiment shown in .

[0127] Figure 15 and Figure 16 is a diagram illustrating a maximum luminance converter according to another embodiment of the present disclosure.

[0128] Reference Figure 15 ,and Figure 13 Compared to the maximum brightness converter 157a shown in FIG. Figure 15 The maximum brightness converter 157b according to one or more embodiments of the present disclosure may further include a frame counter 1574. Therefore, differences therebetween may be mainly described hereinafter, and redundant descriptions of identical or substantially identical components thereof may not be repeated.

[0129] The frame counter 1574 may provide a count number FCN by performing frame counting. A vertical synchronization signal (eg, a VSYNC signal) may be used for frame counting.

[0130] The maximum brightness shifter 1573 may provide the converted input maximum brightness DBVo′ by gradually increasing the input maximum brightness DBVi according to time. For example, the maximum brightness shifter 1573 may provide the converted input maximum brightness DBVo′ by gradually increasing the input maximum brightness DBVi according to the count number FCN.

[0131] When the input maximum brightness is converted (e.g., suddenly or directly) to the input maximum brightness DBVo (e.g., without considering the count number FCN), the user may see changes in the brightness of the image, such as flickering. According to this embodiment, the final converted input maximum brightness DBVo' is provided by gradually increasing the input maximum brightness DBVi according to time (e.g., according to the count number FCN), thereby reducing the user's discomfort.

[0132] According to an embodiment, when at least one of the pattern detection signal TPAT and the brightness detection signal TDBV is not generated, it may be desirable to convert the input maximum brightness DBVo back to the input maximum brightness DBVi before the conversion. The second speed at which the input maximum brightness DBVo decreases to the input maximum brightness DBVi before the conversion may be higher than the first speed at which the input maximum brightness DBVi increases to the input maximum brightness DBVo. For example, when the first speed is 3DBV / 100DBV, the second speed may be 5DBV / 100DBV. Thus, it is possible to prevent or reduce an undesirable (e.g., unnecessary) emphasis effect.

[0133] Figure 17 is a diagram illustrating a grayscale converter according to another embodiment of the present disclosure.

[0134] and Figure 5 Compared with the grayscale converter 15a shown in FIG. Figure 17 The grayscale converter 15c shown in FIG may further include an on-pixel ratio calculator 158 and an on-pixel weight provider 159. Therefore, differences therebetween may be mainly described hereinafter, and redundant descriptions of the same or substantially the same components thereof may not be repeated.

[0135] The on-pixel ratio calculator 158 may calculate the on-pixel ratio OPR by applying a weight to the average value of the input grayscale GVi for each color. For example, the on-pixel ratio calculator 158 may calculate the on-pixel ratio OPR according to Equation 1 above.

[0136] The on-pixel weight provider 159 may provide an on-pixel weight Wopr corresponding to the on-pixel ratio OPR of the input grayscale GVi.

[0137] The compensation offset converter 153 may provide a second compensation offset COFSm by converting the first compensation offset COFS according to the maximum luminance weight Wdbv and the on-pixel weight Wopr. For example, the compensation offset converter 153 may calculate the second compensation offset COFSm by multiplying the first compensation offset COFS by the maximum luminance weight Wdbv and the on-pixel weight Wopr.

[0138] Figure 18 is a diagram illustrating a turned-on pixel weight provider according to an embodiment of the present disclosure.

[0139] For example, when the on-pixel ratio OPR is less than the first threshold ratio CR1, the on-pixel weight provider 159 may increase the on-pixel weight Wopr as the on-pixel ratio OPR increases.

[0140] For example, when the on-pixel ratio OPR is greater than the second threshold ratio CR2, the on-pixel weight provider 159 may reduce the on-pixel weight Wopr as the on-pixel ratio OPR increases. The second threshold ratio CR2 may be greater than the first threshold ratio CR1.

[0141] For example, when the on-pixel ratio OPR is between the first threshold ratio CR1 and the second threshold ratio CR2, the on-pixel weight provider 159 may provide the on-pixel weight Wopr having a maximum value.

[0142] According to this embodiment, it is possible to further emphasize Figure 10 and Figure 11 The effect of the embodiment shown in .

[0143] Figure 19 is a diagram illustrating a grayscale converter according to another embodiment of the present disclosure.

[0144] and Figure 17Compared with the grayscale converter 15c shown in FIG. Figure 19 The grayscale converter 15d shown in FIG may further include a maximum brightness limiter 160. Therefore, differences therebetween may be mainly described hereinafter, and redundant descriptions of the same or substantially the same components thereof may not be repeated.

[0145] When the on-pixel ratio OPR decreases to a reference ratio or less, the maximum brightness limiter 160 may limit the increase of the second compensation offset COFSm. For example, when the on-pixel ratio OPR decreases to a reference ratio or less, the maximum brightness limiter 160 may provide a stuck signal STUCK to the compensation offset converter 153. When the compensation offset converter 153 receives the stuck signal STUCK, the compensation offset converter 153 may limit the second compensation offset COFSm to a reference value or less.

[0146] According to the present embodiment, it is possible to prevent or reduce the situation where excessive brightness appears in an image having a low on-pixel ratio OPR.

[0147] In a display device and a driving method of the display device according to one or more example embodiments of the present disclosure, display quality may be improved and power consumption may be reduced while compensating for a voltage drop amount of a power voltage by using at least one of input maximum brightness and an on-pixel ratio.

[0148] Although some example embodiments have been described, it will be readily appreciated by those skilled in the art that various modifications in the example embodiments are possible without departing from the spirit and scope of the present disclosure. It will be understood that, unless otherwise described, the description of features or aspects in each embodiment should generally be considered to be applicable to other similar features or aspects in other embodiments. Therefore, it will be apparent to those skilled in the art that the features, characteristics and / or elements described in conjunction with a specific embodiment can be used alone or in combination with the features, characteristics and / or elements described in conjunction with other embodiments, unless otherwise specifically stated. Therefore, it will be understood that the foregoing is an illustration of various example embodiments and should not be construed as being limited to the specific example embodiments disclosed herein, and that various modifications to the disclosed example embodiments and other example embodiments are intended to be included within the spirit and scope of the present disclosure as defined in the appended claims and their equivalents.

Claims

1. A display device, comprising: a plurality of pixels configured to receive a data voltage based on a converted grayscale; as well as Grayscale converter, configured as: calculating a first compensation offset based on positions of the plurality of pixels and input grayscales for the plurality of pixels; converting the first compensation offset into a second compensation offset according to a maximum brightness weight based on an input maximum brightness; and calculating the converted grayscale by applying the second compensation offset to the input grayscale, Wherein: when the input maximum brightness is less than a first threshold, the maximum brightness weight increases as the input maximum brightness increases; and when the input maximum brightness is greater than the first threshold, the maximum brightness weight decreases as the input maximum brightness increases, and Wherein: when the input maximum brightness is greater than the first threshold and less than a second threshold that is greater than the first threshold, the maximum brightness weight corresponds to a positive number; when the input maximum brightness corresponds to the second threshold, the maximum brightness weight corresponds to 0; and when the input maximum brightness is greater than the second threshold, the maximum brightness weight corresponds to a negative number.

2. The display device according to claim 1, wherein The grayscale converter comprises: a first lookup table including the positions of the plurality of pixels and voltage drop amounts for reference grayscales for the plurality of pixels; a voltage drop amount calculator configured to calculate a voltage drop amount of the input grayscale according to the first lookup table and the input grayscale; and A compensation offset calculator is configured to calculate the first compensation offset corresponding to the voltage drop amount of the input grayscale.

3. The display device according to claim 2, wherein: The grayscale converter further includes: a maximum brightness weight provider, configured to provide the maximum brightness weight corresponding to the input maximum brightness; a compensation offset converter configured to provide the second compensation offset by converting the first compensation offset according to the maximum luminance weight; and A conversion grayscale calculator is configured to calculate the conversion grayscale by applying the second compensation offset to the input grayscale.

4. The display device according to claim 3, wherein The grayscale converter further includes a maximum brightness converter configured to provide the maximum brightness weight provider with a converted input maximum brightness converted based on the input grayscale and the input maximum brightness.

5. The display device according to claim 4, wherein The maximum brightness converter comprises: a target pattern detector configured to provide a pattern detection signal when a ratio of on-pixels of the input grayscale is less than a reference ratio; an object brightness detector configured to provide a brightness detection signal when the input maximum brightness is within a reference brightness range; and The maximum brightness shifter is configured to provide the converted input maximum brightness by converting the input maximum brightness when receiving the pattern detection signal and the brightness detection signal. The display device according to claim 5 , wherein: The maximum brightness shifter is configured to provide the converted input maximum brightness by gradually increasing the input maximum brightness according to time.

7. The display device according to claim 6, wherein: The maximum brightness converter further includes a frame counter configured to provide a count number by counting frames, and The maximum brightness shifter is configured to provide the converted input maximum brightness by gradually increasing the input maximum brightness according to the counted number.

8. The display device according to claim 3, wherein The grayscale converter further includes a turn-on pixel weight provider configured to provide a turn-on pixel weight corresponding to a turn-on pixel ratio of the input grayscale, and The compensation offset converter is configured to provide the second compensation offset by converting the first compensation offset according to the maximum brightness weight and the on-pixel weight.

9. The display device according to claim 8, wherein When the on-pixel ratio is less than a first threshold ratio, the on-pixel weight increases as the on-pixel ratio increases.

10. The display device according to claim 9, wherein When the on-pixel ratio is greater than a second threshold ratio greater than the first threshold ratio, the on-pixel weight decreases as the on-pixel ratio increases, and When the on-pixel ratio is between the first threshold ratio and the second threshold ratio, the on-pixel weight has a maximum value.

11. The display device according to claim 8, wherein The grayscale converter further includes an on-pixel ratio calculator configured to calculate the on-pixel ratio by applying a weight to an average value of the input grayscale for each color.

12. The display device according to claim 8, wherein The grayscale converter further includes a maximum brightness limiter configured to limit an increase in the second compensation offset when the on-pixel ratio decreases to a reference ratio or less.

13. A method for driving a display device, the method comprising: calculating a first compensation offset based on a position of a pixel and an input grayscale for the pixel; converting the first compensation offset into a second compensation offset according to a maximum brightness weight based on an input maximum brightness; calculating a converted grayscale by applying the second compensation offset to the input grayscale; as well as providing a data voltage to the pixel based on the converted grayscale, Wherein: when the input maximum brightness is less than a first threshold, the maximum brightness weight increases as the input maximum brightness increases; and when the input maximum brightness is greater than the first threshold, the maximum brightness weight decreases as the input maximum brightness increases, and Wherein: when the input maximum brightness is greater than the first threshold and less than a second threshold that is greater than the first threshold, the maximum brightness weight corresponds to a positive number; when the input maximum brightness corresponds to the second threshold, the maximum brightness weight corresponds to 0; and when the input maximum brightness is greater than the second threshold, the maximum brightness weight corresponds to a negative number.

14. The method according to claim 13, further comprising: generating a pattern detection signal when the on-pixel ratio of the input grayscale is less than a reference ratio; When the input maximum brightness is within the reference brightness range, generating a brightness detection signal; as well as When the pattern detection signal and the brightness detection signal are generated, the input maximum brightness is converted.

15. The method according to claim 14, wherein In the step of converting the input maximum brightness, the converted input maximum brightness is provided by gradually increasing the input maximum brightness according to time.

16. The method according to claim 15, further comprising: Provides the number of counts by counting frames, Wherein, in the step of converting the input maximum brightness, the converted input maximum brightness is provided by gradually increasing the input maximum brightness according to the counted number.

Images