Display device and driving method thereof

Abstract

A display device and a driving method thereof are disclosed. The display device includes: a display area including a plurality of pixels; a peak driving determination unit configured to determine whether to perform peak driving based on an input image signal; a normal driving compensation unit including a first luminance look-up table having a first luminance as a peak luminance; a peak driving compensation unit including a second luminance look-up table having a second luminance higher than the first luminance as a peak luminance; a compensation adjustment unit configured to smooth a first luminance gamma curve corresponding to the first luminance look-up table and a second luminance gamma curve corresponding to the second luminance look-up table to generate a peak driving gamma curve, and generate a peak driving look-up table based on the peak driving gamma curve; and a signal control unit configured to generate an image data signal by applying a normal driving look-up table to a part of the display area and applying the peak driving look-up table to another part of the display area.

Description

Technical Field

[0001] The present invention relates to a display device and a driving method thereof, and more particularly, to a display device and a driving method thereof that perform peak driving. Background Art

[0002] As a device for displaying images, recently, organic light-emitting diode displays have attracted much attention.

[0003] An organic light-emitting diode display displays images using organic light-emitting diodes that emit light through the recombination of electrons and holes. The organic light-emitting diode display has a self-luminous characteristic and, unlike a liquid crystal display device, does not require an additional light source, so the thickness and weight can be reduced. In addition, the organic light-emitting diode display exhibits high-quality characteristics such as low power consumption, high brightness, and high response speed. Summary of the Invention

[0004] In order to reduce power consumption, a display device may calculate a frame load and adjust the brightness of the entire frame according to the frame load. The power consumption of the display device can be reduced by the following method: displaying an image based on a normal peak brightness when the frame load is large, and displaying an image based on a high peak brightness when the frame load is small. The peak brightness represents the brightness of an image when the image is displayed at the maximum color level. The method of displaying an image based on a high peak brightness is called peak driving, and the method of displaying an image based on a normal peak brightness lower than the peak brightness is called normal driving.

[0005] Normal driving and peak driving are applied to the entire frame. In this case, there may be a problem that the brightness of a portion that is displayed darker during normal driving increases during peak driving. If the brightness of a portion that is displayed darker increases during peak driving, the effect of reducing power consumption will be correspondingly reduced.

[0006] In addition, when the gamma of the display device is adjusted based on a high peak brightness, the gamma of the display device may decrease during normal driving. And when the gamma of the display device is adjusted based on a normal peak brightness, there may be a problem that some color levels cannot be displayed during peak driving.

[0007] The technical problem to be solved by the present invention is to provide a display device and a driving method thereof that can perform peak driving locally in a display area.

[0008] A display device according to an embodiment of the present invention includes: a display area including a plurality of pixels; a peak drive determination unit that determines whether to perform peak drive based on an input image signal; a normal drive compensation unit including a first luminance look-up table having a first luminance as a peak luminance; a peak drive compensation unit including a second luminance look-up table having a second luminance higher than the first luminance as a peak luminance; a compensation adjustment unit that smooths a first luminance gamma curve corresponding to the first luminance look-up table and a second luminance gamma curve corresponding to the second luminance look-up table to generate a peak drive gamma curve, and generates a look-up table for peak drive based on the peak drive gamma curve; and a signal control unit that applies a look-up table for normal drive to a part of the display area and applies the look-up table for peak drive to another part of the display area to generate an image data signal.

[0009] The look-up table for normal drive may be the first luminance look-up table.

[0010] The gamma value of the first luminance gamma curve may be the same as the gamma value of the second luminance gamma curve.

[0011] The peak drive determination unit may analyze a frame load based on the input image signal and determine the peak drive when the frame load is less than a reference load.

[0012] The display device may further include: a gradation analysis unit that determines a peak drive reference gradation based on the input image signal, wherein the compensation adjustment unit may smooth the first luminance gamma curve and the second luminance gamma curve based on the peak drive reference gradation to generate the peak drive gamma curve.

[0013] The gradation analysis unit may calculate an average gradation of an image based on the input image signal and determine the average gradation of the image as the peak drive reference gradation.

[0014] The gradation analysis unit may calculate a highest gradation of an image based on the input image signal and determine a gradation lower than the highest gradation of the image by a predetermined level as the peak drive reference gradation.

[0015] The gradation analysis unit may divide the display area into a plurality of blocks, select a block to perform the peak drive from the plurality of blocks, and transmit peak drive block information including information about the block to perform the peak drive to the signal control unit. The signal control unit may apply the look-up table for peak drive to the input image signal corresponding to the block to perform the peak drive among the plurality of blocks according to the peak drive block information.

[0016] The gradation analysis unit may compare the average gradation of each of the plurality of blocks with the peak drive reference gradation, and select, as the blocks to perform peak drive, the blocks in which the average gradation is greater than the peak drive reference gradation.

[0017] The gradation analysis unit may select, as the blocks to perform peak drive, the blocks in the plurality of blocks in units of regions including blocks arranged in a first direction.

[0018] A method for driving a display device according to another embodiment of the present invention includes the steps of: receiving an input image signal; determining whether to perform peak drive based on the input image signal; smoothing a first luminance gamma curve having a first luminance as a peak luminance and a second luminance gamma curve having a second luminance higher than the first luminance as a peak luminance to generate a peak drive gamma curve; generating a peak drive lookup table based on the peak drive gamma curve; applying a normal drive lookup table to the input image signal corresponding to a part of the display area and applying the peak drive lookup table to the input image signal corresponding to another part of the display area to generate an image data signal; and displaying an image according to the image data signal.

[0019] The normal drive lookup table may include values of image data signals for gradations according to the first luminance gamma curve.

[0020] The screen load may be analyzed based on the input image signal, and it may be determined to perform the peak drive when the screen load is less than a reference load.

[0021] The display area may be divided into a plurality of blocks, and the blocks to perform the peak drive may be selected from the plurality of blocks, wherein the peak drive lookup table may be applied to the input image signal corresponding to the blocks to perform the peak drive.

[0022] Each of the plurality of blocks may include at least one pixel.

[0023] The average gradation of each of the plurality of blocks may be compared with the peak drive reference gradation, and the blocks in which the average gradation is greater than the peak drive reference gradation may be selected as the blocks to perform the peak drive.

[0024] The highest gradation of each of the plurality of blocks may be compared with the peak drive reference gradation, and the blocks in which the highest gradation is greater than the peak drive reference gradation may be selected as the blocks to perform the peak drive.

[0025] The average gradation may be analyzed for each region including a part of the plurality of regions, and the regions in which the average gradation is greater than the peak drive reference gradation may be selected as the regions to perform the peak drive.

[0026] The display area may be divided into a plurality of regions including blocks arranged in a first direction. The normal driving lookup table may be applied to the input image signals corresponding to a part of the plurality of regions, and the peak driving lookup table may be applied to the input image signals corresponding to another part of the plurality of regions.

[0027] The gamma value of the first luminance gamma curve and the gamma value of the second luminance gamma curve may be the same.

[0028] The display device may perform peak driving on a part of the display area and normal driving on another part. Since peak driving and normal driving can be applied simultaneously in one screen, the brightness of the darker - displayed part in the image may not increase due to peak driving. BRIEF 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 block diagram showing a driving control unit according to an embodiment of the present invention.

[0031] Figure 3 is a graph showing a first luminance gamma curve according to an embodiment of the present invention.

[0032] Figure 4 is a graph showing a second luminance gamma curve according to an embodiment of the present invention.

[0033] Figures 5 to 7 is a graph showing a gamma curve for peak driving according to an embodiment of the present invention.

[0034] Figure 8 is a block diagram showing a display area including a region where peak driving can be locally performed according to an embodiment of the present invention.

[0035] Figure 9 is a block diagram showing a display area including a region where peak driving can be locally performed according to another embodiment of the present invention.

[0036] Figure 10 is a flowchart showing a driving method of a display device according to an embodiment of the present invention.

[0037]

REFERENCE NUMERAL DESCRIPTION

[0038] 100: Signal control unit 200: Gate driving unit

[0039] 300: Data driving unit 400: Driving control unit

[0040] 410: Peak drive determination unit 420: Normal drive compensation unit

[0041] 430: Peak drive compensation unit 440: Color level analysis unit

[0042] 450: Compensation adjustment unit 600: Display unit Detailed implementation manners

[0043] Hereinafter, multiple embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those having basic knowledge in the technical field to which the present invention pertains can easily implement it. The present invention can be implemented in various different forms and is not limited to the embodiments described herein.

[0044] Moreover, in multiple embodiments, the same reference numerals are used for components having the same configuration and are typically described in the first embodiment, and only the configurations different from the first embodiment are described in other embodiments.

[0045] To clearly illustrate the present invention, parts irrelevant to the description are omitted, and throughout the specification, the same reference numerals are given to the same or similar components.

[0046] Throughout the specification, when it is mentioned that a certain part "includes" a certain component, this does not exclude other components without particularly contrary descriptions, but means that other components may also be included.

[0047] Hereinafter, with reference to Figures 1 to 9 A display device according to an embodiment of the present invention will be described.

[0048] Figure 1 is a block diagram showing a display device according to an embodiment of the present invention. Figure 2 is a block diagram showing a drive control unit according to an embodiment of the present invention. Figure 3 is a graph showing a first luminance gamma curve according to an embodiment of the present invention. Figure 4 is a graph showing a second luminance gamma curve according to an embodiment of the present invention. Figures 5 to 7 is a graph showing a gamma curve for peak drive according to an embodiment of the present invention. Figure 8 is a block diagram showing a display area including an area where peak drive can be locally performed according to an embodiment of the present invention. Figure 9 is a block diagram showing a display area including an area where peak drive can be locally performed according to another embodiment of the present invention.

[0049] With reference to Figures 1 to 9, the display device includes a signal control unit 100, a gate driving unit 200, a data driving unit 300, a driving control unit 400, and a display unit 600. Although the case where the driving control unit 400 is arranged relatively independently of the signal control unit 100 is illustrated here, the driving control unit 400 may be included in the signal control unit 100.

[0050] The signal control unit 100 receives an input image signal ImS and a synchronization signal CONT input by an external device. The input image signal ImS includes luminance information of a plurality of pixels PX. The luminance has a predetermined number of gray levels. The synchronization signal CONT may include a horizontal synchronization signal, a vertical synchronization signal, and a main clock signal.

[0051] The signal control unit 100 generates a first driving control signal CONT1, a second driving control signal CONT2, and an image data signal DAT according to the input image signal ImS and the synchronization signal CONT. The signal control unit 100 may divide the input image signal ImS in units of frames according to the vertical synchronization signal, and divide the input image signal ImS in units of gate lines according to the horizontal synchronization signal, so as to generate the image data signal DAT.

[0052] The signal control unit 100 receives a compensation value CV and peak driving block information PBK from the driving control unit 400. The signal control unit 100 may apply the compensation value CV to the input image signal ImS to generate the image data signal DAT. The signal control unit 100 may adjust the level of the image data signal DAT according to the compensation value CV.

[0053] The signal control unit 100 transmits the first driving control signal CONT1 to the gate driving unit 200. The signal control unit 100 transmits the image data signal DAT and the second driving control signal CONT2 to the data driving unit 300.

[0054] The display unit 600 includes a plurality of pixels PX and displays an image. The area where a plurality of pixels PX are arranged to display an image is called a display area or a screen. The display unit 600 includes a plurality of signal lines connected to the plurality of pixels PX. The plurality of signal lines include a plurality of scan lines and a plurality of data lines. The plurality of scan lines may extend substantially in the row direction and be almost parallel to each other. The plurality of data lines may extend substantially in the column direction and be almost parallel to each other. The plurality of pixels PX may be arranged in an area where the plurality of scan lines and the plurality of data lines intersect. The signal lines included in the display unit 600 may be variously changed according to the structure of the plurality of pixels PX included in the display unit 600.

[0055] The gate driving unit 200 is connected to a plurality of gate lines. The gate driving unit 200 generates a plurality of gate signals G[1]-G[n] according to the first driving control signal CONT1. The plurality of gate signals G[1]-G[n] are composed of a combination of a gate-on voltage and a gate-off voltage. The gate driving unit 200 can sequentially apply the gate signals G[1]-G[n] with the gate-on voltage to the plurality of gate lines.

[0056] The data driving unit 300 is connected to a plurality of data lines. The data driving unit 300 can sample and hold the image data signal DAT according to the second driving control signal CONT2, and apply data voltages D[1]-D[m] to the plurality of data lines. The data driving unit 300 can apply the data voltages D[1]-D[m] with a predetermined voltage range to the plurality of data lines corresponding to the gate signals G[1]-G[n] with the gate-on voltage.

[0057] The driving control unit 400 receives the input image signal ImS. The driving control unit 400 provides the compensation value CV and the peak driving block information PBK to the signal control unit 100 in a manner capable of performing local peak driving according to the input image signal ImS. The peak driving block information PBK includes information about the block or region where peak driving is to be performed. The signal control unit 100 can apply the compensation value CV to a part of the blocks based on the peak driving block information PBK to generate the image data signal DAT, and can perform local peak driving accordingly.

[0058] Local peak driving is a driving method in which an image is displayed based on a first luminance in a part of the display area, and an image is displayed based on a second luminance higher than the first luminance in another part of the display area. The first luminance can be the peak luminance during normal driving, and the second luminance can be the peak luminance during peak driving.

[0059] The driving control unit 400 may include a peak driving determination unit 410, a normal driving compensation unit 420, a peak driving compensation unit 430, a color level analysis unit 440, and a compensation adjustment unit 450.

[0060] The peak driving determination unit 410 receives the input image signal ImS. The peak driving determination unit 410 analyzes the screen load based on the input image signal ImS. The screen load can be the ratio of the part of the image displayed based on the input image signal ImS to the entire screen. The peak driving determination unit 410 can determine to perform normal driving when the screen load is above the reference load, and can determine to perform peak driving when the screen load is less than the reference load. The reference load can be a predetermined value. For example, the reference load can be set to 20%, and peak driving can be determined to be performed when the part displayed at a color level greater than the 0 color level is less than 20% in the entire screen.

[0061] In the case where peak driving is determined to be executed, the peak driving determination unit 410 transmits a peak driving enable signal to the normal driving compensation unit 420 and the peak driving compensation unit 430.

[0062] The normal driving compensation unit 420 may include a first luminance lookup table having a first luminance as the peak luminance. For example, the first luminance may be 1000 nits. The first luminance lookup table may include luminance values for color levels according to the first luminance gamma curve shown in Figure 3 . Or, the first luminance lookup table may include values of the image data signal DAT for color levels according to the first luminance gamma curve. If the normal driving compensation unit 420 receives the peak driving enable signal, it may transmit the first luminance lookup table to the compensation adjustment unit 450.

[0063] The peak driving compensation unit 430 may include a second luminance lookup table having a second luminance as the peak luminance. For example, the second luminance may be 2000 nits. The second luminance lookup table may include luminance values for color levels according to the second luminance gamma curve shown in Figure 4 . Or, the second luminance lookup table may include values of the image data signal DAT for color levels according to the second luminance gamma curve. If the peak driving compensation unit 430 receives the peak driving enable signal, it may transmit the second luminance lookup table to the compensation adjustment unit 450.

[0064] The gamma value of the first luminance gamma curve and the gamma value of the second luminance gamma curve may be the same. For example, the gamma value of the first luminance gamma curve and the gamma value of the second luminance gamma curve may be the same and both be 2.2.

[0065] The color level analysis unit 440 receives the input image signal ImS. It may determine a peak driving reference color level (e.g., Figure 5 R1 of Figure 6 R2 of Figure 7 R3 of based on the input image signal ImS. The peak driving reference color level may serve as a reference for applying one of normal driving and peak driving.

[0066] For example, the color level analysis unit 440 may calculate the average color level of the image displayed in the display area based on the input image signal ImS. The color level analysis unit 440 may determine the average color level of the image as the peak driving reference color level. Or, the color level analysis unit 440 may calculate the highest color level of the image displayed in the display area and determine a color level that is a predetermined level lower than the highest color level as the peak driving reference color level.

[0067] Alternatively, the gradation analysis unit 440 may also have one or more pre-determined peak driving reference gradations, and determine as the peak driving reference gradation the peak driving reference gradation having the same value as the average gradation of the image displayed in the display area or the peak driving reference gradation having a value lower than the highest gradation. For example, when the display device can display gradations from 0 to 255, the gradation analysis unit 440 may determine the first reference gradation R1 (e.g., 32 gradations) as the low gradation as the peak driving reference gradation. Alternatively, the gradation analysis unit 440 may determine the second reference gradation R2 (e.g., 128 gradations) as the intermediate gradation as the peak driving reference gradation. Alternatively, the gradation analysis unit 440 may determine the third reference gradation R3 (e.g., 192 gradations) as the high gradation as the peak driving reference gradation.

[0068] The gradation analysis unit 440 may transfer the peak driving reference gradation to the normal driving compensation unit 420 and the peak driving compensation unit 430. The normal driving compensation unit 420 may transfer the entire first luminance lookup table to the compensation adjustment unit 450 or transfer only the values of the image data signal DAT for gradations below the peak driving reference gradation in the first luminance lookup table to the compensation adjustment unit 450 according to the peak driving reference gradation. The peak driving compensation unit 430 may transfer the entire second luminance lookup table to the compensation adjustment unit 450 or transfer only the values of the image data signal DAT for gradations greater than the peak driving reference gradation in the second luminance lookup table to the compensation adjustment unit 450 according to the peak driving reference gradation.

[0069] The compensation adjustment unit 450 generates a lookup table for peak driving based on the first luminance lookup table and the second luminance lookup table. The compensation adjustment unit 450 may Figure 3 first luminance gamma curve of Figure 4 and Figures 5 to 7 second luminance gamma curve of Figures 5 to 7 perform smoothing to generate a peak driving gamma curve as

[0070] The compensation adjustment unit 450 can smooth the first luminance gamma curve and the second luminance gamma curve based on the peak drive reference color level to generate a peak drive gamma curve. That is, the peak drive gamma curve generated from the compensation adjustment unit 450 can vary according to the value of the peak drive reference color level determined by the color level analysis unit 440. When the peak drive reference color level is the first reference color level R1, as Figure 5 shown, the gamma curve can be smoothed near the first reference color level R1 to generate a peak drive gamma curve. When the peak drive reference color level is the second reference color level R2, as Figure 6 shown, the gamma curve can be smoothed near the second reference color level R2 to generate a peak drive gamma curve. When the peak drive reference color level is the third reference color level R3, as Figure 7 shown, the gamma curve can be smoothed near the third reference color level R3 to generate a peak drive gamma curve.

[0071] The compensation adjustment unit 450 can generate a lookup table for peak drive based on the peak drive gamma curve. The lookup table for peak drive can include a compensation value CV for the color level. The compensation adjustment unit 450 transfers the compensation value CV according to the lookup table for peak drive to the signal control unit 100.

[0072] The color level analysis unit 440 can divide the display area into multiple blocks (e.g., Figure 8 and Figure 9 BK11 - BK1y, BK21 - BK2y, BK31 - BK3y,..., BKx1 - BKxy), and can analyze the average color level or the highest color level of each of the multiple blocks based on the input image signal ImS. Each of the multiple blocks can include at least one pixel. The color level analysis unit 440 can select the blocks to perform peak drive from the multiple blocks based on the average color level or the highest color level of each of the multiple blocks. The color level analysis unit 440 can compare the average color level of each of the multiple blocks with the peak drive reference color level, so as to select the blocks with an average color level greater than the peak drive reference color level as the blocks to perform peak drive. Or, the color level analysis unit 440 can compare the highest color level of each of the multiple blocks with the peak drive reference color level, so as to select the blocks with the highest color level greater than the peak drive reference color level as the blocks to perform peak drive. The color level analysis unit 440 transfers the peak drive block information PBK including information about the blocks to perform peak drive to the signal control unit 100.

[0073] As Figure 8 and Figure 9As shown, the display unit 600 may include a plurality of blocks BK11-BK1y, BK21-BK2y, BK31-BK3y, ..., BKx1-BKxy. The plurality of blocks BK11-BK1y, BK21-BK2y, BK31-BK3y, ..., BKx1-BKxy may be arranged in a matrix form with y blocks arranged in the first direction DR1 and x blocks arranged in the second direction DR2. The gradation analysis unit 440 may select a block to be subjected to peak driving from among the plurality of blocks BK11-BK1y, BK21-BK2y, BK31-BK3y, ..., BKx1-BKxy. For example, the gradation analysis unit 440 selects, as blocks to be subjected to the peak driving, a plurality of blocks selected in units of regions including blocks arranged along the first direction DR1 among the plurality of blocks BK11-BK1y, BK21-BK2y, BK31-BK3y, ..., BKx1-BKxy. The first direction DR1 may be the row direction, and the second direction DR2 may be the column direction.

[0074] Based on the peak driving block information PBK, the signal control unit 100 applies a compensation value CV according to a peak driving look-up table to an input image signal ImS corresponding to a block to be subjected to peak driving among the plurality of blocks BK11-BK1y, BK21-BK2y, BK31-BK3y, ..., BKx1-BKxy to generate an image data signal DAT. Further, the signal control unit 100 may generate an image data signal DAT without applying the compensation value CV to an input image signal ImS corresponding to a block not subjected to peak driving. The image data signal DAT to which the compensation value CV is not applied may be generated according to a first luminance look-up table. The first luminance look-up table, as a normal driving look-up table, may be stored in the signal control unit 100.

[0075] In this way, local peak driving may be performed as follows: An image is displayed for a part of the plurality of blocks BK11-BK1y, BK21-BK2y, BK31-BK3y, ..., BKx1-BKxy based on the image data signal DAT generated by applying a normal driving look-up table, and an image is displayed for another part based on the image data signal DAT generated by applying a peak driving look-up table.

[0076] In addition, the gradation analysis unit 440 may analyze the average gradation or the highest gradation for each region (zone) including a part of the plurality of blocks. As Figure 8 shown, the display unit 600 may be divided into a plurality of regions (region #1, region #2, region #3, ..., region #x) including blocks arranged along the first direction DR1. Or, as Figure 9As shown, the display unit 600 can be divided into a plurality of regions (region #1, region #2, region #3, ..., region #y) including blocks arranged along the second direction DR2.

[0077] The gradation analysis unit 440 can compare the average gradation and the peak driving reference gradation of each of the plurality of regions (region #1, region #2, region #3, ..., region #x or region #1, region #2, region #3, ..., region #y), and select the regions where the average gradation is greater than the peak driving reference gradation as the regions where peak driving is to be performed. Alternatively, the gradation analysis unit 440 can compare the highest gradation and the peak driving reference gradation of each of the plurality of regions (region #1, region #2, region #3, ..., region #x or region #1, region #2, region #3, ..., region #y), and select the regions where the highest gradation is greater than the peak driving reference gradation as the regions where peak driving is to be performed. The gradation analysis unit 440 can transfer the peak driving block information PBK including information about the regions where peak driving is to be performed to the signal control unit 100. Accordingly, the normal driving lookup table or the peak driving lookup table can be applied according to each region (region #1, region #2, region #3, ..., region #x or region #1, region #2, region #3, ..., region #y) to generate the image data signal DAT, and local peak driving can be performed.

[0078] Hereinafter, Figures 1 to 9 together with Figure 10 a driving method of the display device will be described.

[0079] Figure 10 is a flowchart showing a driving method of a display device according to an embodiment of the present invention.

[0080] Referring to Figure 10 , the display device receives an input image signal ImS (S110). The input image signal ImS includes luminance information of a plurality of pixels PX.

[0081] The display device determines to perform peak driving based on the input image signal ImS (S120). The display device can analyze the screen load based on the input image signal ImS, and determine to perform peak driving when the screen load is less than the reference load. The screen load can be the ratio of the part of the screen displaying the image based on the input image signal ImS to the entire screen. The display device can determine to perform normal driving when the screen load is above the reference load.

[0082] The display device obtains a first luminance look-up table and a second luminance look-up table (S130). The first luminance look-up table may include luminance values for color levels according to a first luminance gamma curve having the first luminance as a peak luminance. Alternatively, the first luminance look-up table may include values of the image data signal DAT for color levels according to the first luminance gamma curve. The second luminance look-up table may include luminance values for color levels according to a second luminance gamma curve having the second luminance as a peak luminance. Alternatively, the second luminance look-up table may include values of the image data signal DAT for color levels according to the second luminance gamma curve.

[0083] The display device generates a look-up table for peak driving based on the first luminance look-up table and the second luminance look-up table (S140). The display device may generate a peak driving gamma curve by smoothing the first luminance gamma curve and the second luminance gamma curve. The display device may generate a look-up table for peak driving based on the peak driving gamma curve. The look-up table for peak driving may include compensation values CV for color levels. Alternatively, the look-up table for peak driving may include values of the image data signal DAT for color levels.

[0084] The display device generates the image data signal DAT by applying the look-up table for peak driving to the input image signal ImS (S150). The image data signal DAT may be generated by applying a normal driving look-up table to the input image signal ImS corresponding to a part of the display area and applying the look-up table for peak driving to the input image signal ImS corresponding to another part of the display area. The normal driving look-up table may be the first luminance look-up table.

[0085] The display device displays an image by generating data voltages D[1]-D[m] according to the image data signal DAT and applying the data voltages D[1]-D[m] to a plurality of pixels PX (S160). That is, an image is displayed in a part of the display area according to the image data signal DAT generated by applying the normal driving look-up table, and an image is displayed in another part of the display area according to the image data signal DAT generated by applying the look-up table for peak driving, thereby performing local peak driving.

[0086] The accompanying drawings and the detailed description of the invention referred to above are only exemplary examples of the present invention, which are only used for the purpose of illustrating the present invention and are not used to limit the meaning or the protection scope of the present invention described in the claims. Therefore, those with basic knowledge in the technical field should understand that various modifications and equivalent other embodiments can be achieved therefrom. Therefore, the true protection scope of the present invention should be determined by the technical idea of the claims.

Claims

1. A display device, comprising: A display area including a plurality of pixels; A peak driving determination unit that analyzes a frame load based on an input image signal and determines to perform the peak driving when the frame load is less than a reference load; A normal driving compensation unit including a first luminance look-up table having a first luminance as a peak luminance; A peak driving compensation unit including a second luminance look-up table having a second luminance higher than the first luminance as a peak luminance; A compensation adjustment unit that smooths a first luminance gamma curve corresponding to the first luminance look-up table and a second luminance gamma curve corresponding to the second luminance look-up table to generate a peak driving gamma curve, and generates a look-up table for peak driving based on the peak driving gamma curve; And A signal control unit that generates an image data signal by applying a look-up table for normal driving to a part of the display area and applying the look-up table for peak driving to another part of the display area for an image of one frame.

2. The display device according to claim 1, wherein The look-up table for normal driving is the first luminance look-up table.

3. The display device according to claim 1, wherein The gamma value of the first luminance gamma curve is the same as the gamma value of the second luminance gamma curve.

4. The display device according to claim 1, wherein, It further includes: A gradation analysis unit that determines a peak driving reference gradation based on the input image signal, wherein the compensation adjustment unit smooths the first luminance gamma curve and the second luminance gamma curve based on the peak driving reference gradation to generate the peak driving gamma curve.

5. The display device according to claim 4, wherein The gradation analysis unit calculates an average gradation of an image based on the input image signal and determines the average gradation of the image as the peak driving reference gradation.

6. The display device according to claim 4, wherein The gradation analysis unit calculates a highest gradation of an image based on the input image signal and determines a gradation lower by a predetermined level than the highest gradation of the image as the peak driving reference gradation.

7. The display device according to claim 4, wherein The gradation analysis unit divides the display area into a plurality of blocks, selects blocks to perform the peak driving from the plurality of blocks, and transmits peak driving block information including information about the blocks to perform the peak driving to the signal control unit, The signal control unit applies the look-up table for peak driving to the input image signal corresponding to the blocks to perform peak driving among the plurality of blocks according to the peak driving block information.

8. The display device according to claim 7, wherein The gradation analysis unit compares the average gradation of each of the plurality of blocks with the peak driving reference gradation and selects blocks with an average gradation greater than the peak driving reference gradation as the blocks to perform the peak driving.

9. The display device according to claim 7, wherein The gradation analysis unit selects blocks to perform the peak driving in units of areas including blocks arranged in a first direction among the plurality of blocks.

10. A driving method for a display device, comprising the following steps: Receiving an input image signal; Analyzing a frame load based on the input image signal, and determining to perform peak driving when the frame load is less than a reference load; Smoothing a first luminance gamma curve with a first luminance as a peak luminance and a second luminance gamma curve with a second luminance higher than the first luminance as a peak luminance to generate a peak driving gamma curve; Generating a look-up table for peak driving based on the peak driving gamma curve; For an image of one frame, applying a look-up table for normal driving to the input image signal corresponding to a part of the display area, and applying the look-up table for peak driving to the input image signal corresponding to another part of the display area to generate an image data signal; And Displaying an image according to the image data signal.

11. The driving method for a display device according to claim 10, wherein The look-up table for normal driving includes values of the image data signal for color levels according to the first luminance gamma curve.

12. The driving method of the display device according to claim 10, wherein, It further comprises the following steps: Dividing the display area into a plurality of blocks, and selecting the blocks to perform the peak driving from the plurality of blocks, wherein, applying the look-up table for peak driving to the input image signal corresponding to the blocks to perform the peak driving.

13. The driving method for a display device according to claim 12, wherein Each of the plurality of blocks includes at least one pixel.

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