Display device

Abstract

A display device according to an embodiment of the present invention, which is intended to solve the technical problem, includes: a timing control unit that provides data including a pre-emphasis value and an image data value; and a data driving unit that supplies a pre-emphasis voltage generated based on the pre-emphasis value to a data line during a first period of a horizontal period, and supplies a data voltage generated based on the image data value to the data line during a second period of the horizontal period. The timing control unit provides data in which the pre-emphasis value changes in accordance with a screen mode selected from a plurality of screen modes having different target color coordinates.

Description

Technical Field

[0001] The present invention relates to a display device. Background Art

[0002] With the development of information technology, the importance of display devices as a medium connecting users and information is becoming increasingly prominent. As a result, the use of display devices such as liquid crystal display devices (LCDs) and organic light emitting display devices (OLEDs) is increasing.

[0003] The display device may include pixels connected to scan lines and data lines, respectively, a scan driving portion for driving the scan lines, and a data driving portion for driving the data lines.

[0004] In order to stably display an image in such a display device, data signals must be stably supplied to pixels within a predetermined time (i.e., a scanning signal supply period). However, due to increased resolution and larger panels, the data signals may not be fully charged to a desired voltage (target voltage) or discharged during the scanning signal supply period.

[0005] In order to overcome the above-mentioned problems, a method of supplying a pre-emphasis voltage has been proposed. The method of supplying the pre-emphasis voltage can reduce a driving delay time by temporarily applying a pre-emphasis voltage greater than a data voltage. Summary of the Invention

[0006] In addition, the display device can provide multiple screen modes that can change the background color to warm or cool colors, taking into account the user's viewing environment and preferences. Since the target color coordinates are set differently according to the screen mode, white balance can be applied to compensate for the target color coordinates.

[0007] However, when white balancing is applied, the RGB ratio of a chromaticity diagram (e.g., CIE 1931) is changed, and thus the data to be compensated also changes. Therefore, when data charging time is insufficient due to increased display resolution and larger panels, the linearity of color coordinates depending on the screen mode may be distorted.

[0008] The technical problem to be solved by the present invention is to provide a display device capable of maintaining the linearity of color coordinates when the screen mode of a high-resolution display panel is changed.

[0009] The technical problem to be solved by the present invention is to provide a method for driving a display device capable of maintaining the linearity of color coordinates when the screen mode of a high-resolution display panel is changed.

[0010] However, the purpose of the present invention is not limited to the above purpose, and the present invention can be expanded in various ways without departing from the scope of the invention.

[0011] A display device according to an embodiment of the present invention for solving the technical problem includes: a timing control unit that provides data including a pre-emphasis value and an image data value; and a data driving unit that supplies a pre-emphasis voltage generated based on the pre-emphasis value to a data line during a first time period of a horizontal time period, and supplies a data voltage generated based on the image data value to the data line during a second time period of the horizontal time period.

[0012] The timing control section provides data in which the pre-emphasis value is changed in accordance with one screen mode selected from a plurality of screen modes having different target color coordinates.

[0013] The plurality of screen modes may include a first screen mode having first target color coordinates, a second screen mode having second target color coordinates, and a third screen mode having third target color coordinates.

[0014] The first target color coordinates to the third target color coordinates can be defined by first and second coordinates of rectangular coordinates, the first and second coordinates of the second target color coordinates are greater than the first and second coordinates of the first target color coordinates, and the first and second coordinates of the third target color coordinates are smaller than the first and second coordinates of the first target color coordinates.

[0015] The timing control section may compare the image data value of a previous horizontal period with the image data value of a current horizontal period to determine the pre-emphasis value corresponding to the current horizontal period.

[0016] The timing control unit can calculate a first difference value between the first target color coordinates and the measured color coordinates according to the grayscale when the first screen mode is selected, and use the first difference value to calculate a first compensation value, and add the first compensation value to the pre-emphasis value; calculate a second difference value between the second target color coordinates and the measured color coordinates according to the grayscale when the second screen mode is selected, and use the second difference value to calculate a second compensation value, and add the second compensation value to the pre-emphasis value; calculate a third difference value between the third target color coordinates and the measured color coordinates according to the grayscale when the third screen mode is selected, and use the third difference value to calculate a third compensation value, and add the third compensation value to the pre-emphasis value.

[0017] The first to third compensation values ​​may be calculated using the following Mathematical Formula 1.

[0018] [Mathematical formula 1]

[0019] Compensation value = (Δy / 0.001) + (Δy-Δx) / 0.001 (where Δx is the difference between the first coordinate of the target coordinate and the first coordinate of the measured coordinate, and Δy is the difference between the second coordinate of the target coordinate and the second coordinate of the measured coordinate)

[0020] The second compensation value may be greater than or equal to the first compensation value, and the third compensation value may be less than or equal to the first compensation value.

[0021] The timing control section may determine the pre-emphasis value based on a lookup table in which the pre-emphasis values ​​corresponding to the image data value of a previous horizontal period and the image data value of a current horizontal period are recorded.

[0022] The lookup table may include a first lookup table corresponding to the first screen mode, a second lookup table corresponding to the second screen mode, and a third lookup table corresponding to the third screen mode.

[0023] The pre-emphasis values ​​included in the second lookup table may be greater than or equal to the corresponding pre-emphasis values ​​included in the first lookup table, and the pre-emphasis values ​​included in the third lookup table may be less than or equal to the corresponding pre-emphasis values ​​included in the first lookup table.

[0024] The device may further include a gamma reference voltage supply unit configured to supply a gamma reference voltage.

[0025] The gamma reference voltages may include a lowest gamma reference voltage corresponding to a lowest grayscale value and a highest gamma reference voltage corresponding to a highest grayscale value.

[0026] The data driving part may include a grayscale voltage generating part that divides the gamma reference voltage to generate a plurality of grayscale voltages.

[0027] The data driving unit may select one grayscale voltage corresponding to the pre-emphasis value from the plurality of grayscale voltages to generate the pre-emphasis voltage, and may select one grayscale voltage corresponding to the image data value from the plurality of grayscale voltages to generate the data voltage.

[0028] The device may further include: a scan driving unit that supplies scan signals through the scan lines; and a pixel unit that includes a plurality of pixels connected to the scan lines and the data lines.

[0029] A method for driving a display device according to an embodiment of the present invention for solving the technical problem includes the following steps: providing data including a pre-emphasis value and an image data value; supplying a gamma reference voltage; and supplying a pre-emphasis voltage generated based on the pre-emphasis value and the gamma reference voltage to a data line during a first time period of a horizontal time period, and supplying a data voltage generated based on the image data value and the gamma reference voltage during a second time period of the horizontal time period.

[0030] In the step of providing data including the pre-emphasis value and image data values, the pre-emphasis value is changed in accordance with one screen mode selected from a plurality of screen modes having different target color coordinates.

[0031] The plurality of screen modes may include a first screen mode having first target color coordinates, a second screen mode having second target color coordinates, and a third screen mode having third target color coordinates.

[0032] The first to third target color coordinates can be defined by first and second coordinates of rectangular coordinates, the first and second coordinates of the second target color coordinates are greater than the first and second coordinates of the first target color coordinates, and the first and second coordinates of the third target color coordinates are smaller than the first and second coordinates of the first target color coordinates.

[0033] Providing data including the pre-emphasis value and the image data value may include comparing the image data value of a previous horizontal period with the image data value of a current horizontal period to determine the pre-emphasis value corresponding to the current horizontal period.

[0034] The step of providing data including the pre-emphasis value and the image data value may further include the following steps: when the first screen mode is selected, finding a first difference value between the first target color coordinates and the measured color coordinates according to the grayscale, and using the first difference value to calculate a first compensation value, and adding the first compensation value to the pre-emphasis value; when the second screen mode is selected, finding a second difference value between the second target color coordinates and the measured color coordinates according to the grayscale, and using the second difference value to calculate a second compensation value, and adding the second compensation value to the pre-emphasis value; when the third screen mode is selected, finding a third difference value between the third target color coordinates and the measured color coordinates according to the grayscale, and using the third difference value to calculate a third compensation value, and adding the third compensation value to the pre-emphasis value.

[0035] The first to third compensation values ​​may be calculated using the following Mathematical Formula 1.

[0036] [Mathematical formula 1]

[0037] Compensation value = (Δy / 0.001) + (Δy-Δx) / 0.001 (where Δx is the difference between the first coordinate of the target coordinate and the first coordinate of the measured coordinate, and Δy is the difference between the second coordinate of the target coordinate and the second coordinate of the measured coordinate)

[0038] According to the display device of the embodiment of the present invention, data voltages are differently applied according to screen modes, thereby being able to maintain the linearity of color coordinates when the screen mode of the high-resolution display panel is changed.

[0039] According to the driving method of the display device according to the embodiment of the present invention, data voltages are applied differently according to screen modes, thereby maintaining the linearity of color coordinates when the screen mode of the high-resolution display panel is changed.

[0040] However, the effects of the present invention are not limited to the above-mentioned effects, and various extensions can be achieved without departing from the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 FIG. 1 is a diagram schematically showing the structure of a display device according to an embodiment of the present invention.

[0042] Figure 2 It shows Figure 1 A diagram of one embodiment of a pixel is shown.

[0043] Figure 3 yes Figure 1 The detailed structure diagram of the data driving unit is shown.

[0044] Figure 4is a lookup table according to an embodiment of the present invention.

[0045] Figure 5 This is a waveform diagram for explaining the pre-emphasis voltage and data voltage.

[0046] Figure 6 is the CIE 1931 (x, y) chromaticity diagram.

[0047] Figures 7a to 7c This is a diagram for explaining a phenomenon in which white balance is distorted when one screen mode is selected from a plurality of screen modes.

[0048] Figure 8 is a graph showing measured color coordinates according to grayscale measurement in one screen mode selected from a plurality of screen modes.

[0049] Figure 9 According to an embodiment Figure 1 The detailed structure of the timing control unit is shown in FIG.

[0050] Figures 10a to 10c is a lookup table created according to a screen mode according to an embodiment.

[0051] Figure 11 is a graph showing measured color coordinates of a display device that compensates for a pre-emphasis value when a screen mode is changed.

[0052] Figure 12 is a flowchart illustrating a method for driving a display device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and repeated descriptions of the same components are omitted.

[0054] Figure 1 FIG. 2 is a diagram schematically showing the structure of a display device 100 according to an embodiment of the present invention.

[0055] Reference Figure 1 The display device 100 according to an embodiment of the present invention may include a timing control unit 10 , a gamma reference voltage supply unit 20 , a data driving unit 30 , a scan driving unit 40 and a pixel unit 50 .

[0056] The timing control section 10 may receive inputs such as image data and a synchronization signal and a clock signal for controlling the display of the image data. The timing control section 10 may compensate the image data inputted from the outside to be suitable for image display of the pixel section 50, and provide the compensated data DATA to the data driving section 30. The data DATA may include an image data value for image display and a pre-emphasis value for adding pre-emphasis to the image data value.

[0057] The timing control part 10 may output a data control signal DCS for controlling the operation timing of the data driving part 30 and a scan control signal SCS for controlling the operation timing of the scan driving part 40. Furthermore, the timing control part 10 may output a voltage control signal VCS for controlling the operation timing of the gamma reference voltage supply part 20 and the voltage level of the gamma reference voltage VREF.

[0058] The gamma reference voltage supply part 20 may supply the gamma reference voltage VREF to the data driving part 30. Here, the gamma reference voltage VREF may include a lowest gamma reference voltage corresponding to the lowest grayscale value and a highest gamma reference voltage corresponding to the highest grayscale value.

[0059] In one embodiment, the gamma reference voltage supply unit 20 may be configured to include a direct current to direct current (DC-DC) converter (not shown) and a pulse width modulation (PWM) controller (not shown). Of course, in addition to these, other circuits capable of generating the gamma reference voltage VREF and changing the voltage level of the gamma reference voltage VREF may be used.

[0060] The data driver 30 may be connected to the data lines D1 to Dm and supply data signals to the pixel unit 50 via the data lines D1 to Dm. The data driver 30 may convert the data DATA supplied from the timing control unit 10 into an analog data signal (or voltage). The data driver 30 may output a grayscale voltage corresponding to the data DATA in response to the data control signal DCS from the timing control unit 10. The data DATA may include a pre-emphasis value and an image data value.

[0061] The data driving part 30 may receive the gamma reference voltage VREF from the gamma reference voltage supply part 20 .

[0062] The data driving unit 30 may supply a pre-emphasis voltage generated based on a pre-emphasis value and a gamma reference voltage VREF to the data lines D1 to Dm during a first period of the horizontal period. Furthermore, the data driving unit 30 may supply a data voltage generated based on an image data value and the gamma reference voltage VREF during a second period of the horizontal period. The data signal may include the pre-emphasis voltage and the data voltage.

[0063] In one embodiment, the data driving unit 30 may include a grayscale voltage generating unit 35 that divides the gamma reference voltage VREF to generate a plurality of grayscale voltages. However, the location of the grayscale voltage generating unit 35 is not limited thereto. In one embodiment, the grayscale voltage generating unit 35 may also be included in the gamma reference voltage supply unit 20. The data driving unit 30 may select one of the plurality of grayscale voltages corresponding to the pre-emphasis value to generate the pre-emphasis voltage, and may select one of the plurality of grayscale voltages corresponding to the image data value to generate the data voltage.

[0064] The scan driver 40 can be connected to the scan lines S1-Sn and supply scan signals to the pixel unit 50 via the scan lines S1-Sn. Specifically, the scan driver 40 can shift the gate voltage level in response to the scan control signal SCS from the timing control unit 10 while outputting the scan signals. In one embodiment, the scan driver 40 can be configured using multiple stages of circuits and sequentially supply scan signals to the scan lines S1-Sn.

[0065] The pixel unit 50 may display an image in response to data signals supplied from the data driving unit 30 and scan signals supplied from the scan driving unit 40. The pixel unit 50 may include a plurality of pixels PX connected to scan lines S1 to Sn and data lines D1 to Dm and arranged in a matrix.

[0066] Specifically, pixels PX are selected in units of horizontal lines in response to a scan signal supplied to one of the scan lines S1 to Sn. At this point, each of the pixels PX selected in response to the scan signal can receive a data signal from one of the data lines D1 to Dm connected thereto. Each of the pixels PX receiving the data signal can emit light at a predetermined brightness corresponding to the data signal. Each of the pixels PX can include sub-pixels that display red, green, and blue. However, the colors emitted by the sub-pixels are not limited to this. For example, each of the pixels PX can include sub-pixels that display red, green, blue, and white.

[0067] In order to stably display an image in the pixel unit 50, the data signal must be stably supplied to the pixel PX within a predetermined time (i.e., the period during which the scan signal is supplied). However, due to increased resolution and larger panels, the data signal may not be fully charged to the desired voltage (target voltage) or discharged during the period during which the scan signal is supplied. To compensate for this, the driving delay time can be reduced by temporarily applying a pre-emphasis voltage greater than the data voltage.

[0068] The timing control unit 10 may determine a pre-emphasis value. Specifically, the timing control unit 10 may compare the image data value of the previous horizontal period with the image data value of the current horizontal period to determine the pre-emphasis value corresponding to the current horizontal period. Furthermore, the timing control unit 10 may change a portion of the image data value to the determined pre-emphasis value.

[0069] According to one embodiment of the present invention, the timing control unit 10 can determine the pre-emphasis grayscale value based on a lookup table 15 that contains pre-emphasis values ​​corresponding to image data values ​​in a previous horizontal period and image data values ​​in a current horizontal period. The values ​​in the lookup table 15 can be set experimentally or statistically based on the debugging results of testing the display device 100.

[0070] Furthermore, the display device 100 can provide various screen modes that can change the background color displayed on the screen to warm or cool colors, taking into account the user's viewing environment and preferences. For example, if the user adjusts the background color of the display device 100 to a warmer color, the screen can emphasize yellow. Conversely, if the user adjusts the background color of the display device 100 to a cooler color, the screen can emphasize blue.

[0071] Since the display device 100 sets target color coordinates differently according to screen modes, white balance for compensating the target color coordinates may be applied. However, when white balance is applied, the RGB ratio of color coordinates (eg, CIE1931) may be changed.

[0072] When the RGB ratio of the color coordinates is changed, the timing control section 10 may change the data DATA to be provided to the data driver 30. Furthermore, in order to maintain the linearity of the color coordinates, the timing control section 10 may also change the pre-emphasis value to be provided to the data driver 30. Specifically, the timing control section 10 may provide the data DATA with a changed pre-emphasis value corresponding to a screen mode selected from a plurality of screen modes to the data driver 30.

[0073] The following will be Figure 9 A specific configuration of the timing control unit 10 that changes the pre-emphasis value according to the screen mode will be described in detail.

[0074] Figure 2 It shows Figure 1 In particular, for ease of explanation, Figure 2 The figure shows pixels connected to the n-th scan line Sn and the m-th data line Dm.

[0075] Reference Figure 2Each pixel PX may include a light emitting diode LD and a pixel circuit PC connected to a data line Dm and a scan line Sn for controlling the light emitting diode LD.

[0076] An anode electrode of the light emitting diode LD may be connected to the pixel circuit PC, and a cathode electrode thereof may be connected to the second voltage VSS.

[0077] Such a light emitting diode LD can generate light of predetermined brightness corresponding to the current supplied from the pixel circuit PC.

[0078] The light emitting diode LD may be formed using an organic light emitting diode or an inorganic light emitting diode such as a micro LED or a quantum dot light emitting diode. Furthermore, the light emitting diode LD may be a light emitting diode formed using a combination of organic and inorganic materials. Figure 2 3 shows a case where the pixel PX includes a single light emitting diode LD. However, in another embodiment, the pixel PX may include a plurality of light emitting diodes, and the plurality of light emitting diodes may be connected in series, in parallel, or in series and parallel.

[0079] When a scan signal is supplied to scan line Sn, pixel circuit PC controls the amount of current supplied to light-emitting diode LD in response to a data signal supplied to data line Dm. To this end, pixel circuit PC includes: a second transistor T2 connected between a first voltage VDD and light-emitting diode LD; a first transistor T1 connected between second transistor T2, data line Dm, and scan line Sn; and a storage capacitor Cst connected between the gate electrode of second transistor T2 and the first electrode of second transistor T2.

[0080] The first transistor T1 includes a gate electrode connected to the scan line Sn and a first electrode connected to the data line Dm.

[0081] Also, a second electrode of the first transistor T1 is connected to one side terminal of the storage capacitor Cst.

[0082] Here, the first electrode is set as one of the source electrode and the drain electrode, and the second electrode is set as the other of the source electrode and the drain electrode. For example, if the first electrode is set as the source electrode, the second electrode is set as the drain electrode.

[0083] When a scan signal is supplied from the scan line Sn, the first transistor T1 connected to the scan line Sn and the data line Dm is turned on, thereby supplying the data signal supplied from the data line Dm to the storage capacitor Cst. At this time, the storage capacitor Cst is charged with a voltage corresponding to the data signal.

[0084] The gate electrode of the second transistor T2 is connected to one terminal of the storage capacitor Cst, the first electrode of the second transistor T2 is connected to the other terminal of the storage capacitor Cst and the first voltage VDD, and the second electrode of the second transistor T2 is connected to the anode electrode of the light emitting diode LD.

[0085] The second transistor T2 controls the amount of current flowing from the first voltage VDD to the second voltage VSS via the light emitting diode LD according to the voltage value stored in the storage capacitor Cst. At this time, the light emitting diode LD generates light according to the amount of current supplied from the second transistor T2.

[0086] The description Figure 2 The pixel structure of the present invention is only one embodiment of the present invention, and the pixel PX of the present invention is not limited to the pixel structure. In fact, the pixel circuit PC can have a circuit structure capable of supplying current to the light emitting diode LD, and can select one of the various currently known structures.

[0087] Figure 3 yes Figure 1 The detailed structure diagram of the data driving unit is shown.

[0088] First, refer to Figure 3 The data driving section 30 may include a shift register section 31 , a latch section 32 , a digital-analog converter unit (DAC unit) 33 , a buffer section 34 , and a grayscale voltage generating section 35 .

[0089] The shift register section 31 shifts the source start pulse SSP supplied from the timing control section 10 according to the source shift clock SSC within one horizontal period and generates a sequential sampling signal. To this end, the shift register section 31 may be equipped with a plurality of shift registers (not shown).

[0090] The latch unit 32 may include: a first latch unit (not shown), which sequentially latches the data DATA provided from the timing control unit 10 in response to the sampling signal provided from the shift register unit 31; and a second latch unit (not shown), which parallelly latches the data of one horizontal line latched by the first latch unit at the rising time point of the source output enable signal SOE and supplies it to the DAC unit 33.

[0091] When latched data DATA is input from the latch unit 32, the DAC unit 33 generates analog data voltages corresponding to the digital data DATA and outputs them to the buffer unit 34. The DAC unit 33 receives grayscale voltages Vg0 to Vg255 from the grayscale voltage generator 35 and generates a pre-emphasis voltage Vpre and a data voltage Vdata corresponding to the data DATA. To this end, the DAC unit 33 may include multiple digital-to-analog converters (DACs).

[0092] The buffer unit 34 can supply the pre-emphasis voltage Vpre and the data voltage Vdata supplied from the DAC unit 33 to each of the data lines D1 to Dm. Although not specifically shown, the buffer unit 34 includes a plurality of output buffers (not shown) connected one-to-one to the data lines D1 to Dm. The output buffers can be configured using operational amplifiers.

[0093] The grayscale voltage generating unit 35 may divide the gamma reference voltage VREF into grayscale voltages Vg0 to Vg255. Here, the gamma reference voltage VREF may include a high gamma reference voltage VGMA_UH and a low gamma reference voltage VGMA_UL.

[0094] In one embodiment, the grayscale voltage generating unit 35 may include: a first voltage distributing unit 36 ​​for dividing the gamma reference voltage VREF to generate intermediate gamma reference voltages VGMA1 to VGMA9; and a second voltage distributing unit 37 for dividing the intermediate gamma reference voltages VGMA1 to VGMA9 to generate grayscale voltages Vg0 to Vg255.

[0095] The first voltage distribution unit 36 ​​may generate intermediate gamma reference voltages VGMA1 to VGMA9 by dividing the high gamma reference voltage VGMA_UH and the low gamma reference voltage VGMA_UL using a plurality of resistor elements connected in series.

[0096] The second voltage distribution unit 37 may generate grayscale voltages Vg0 to Vg255 by dividing each of the intermediate gamma reference voltages VGMA1 to VGMA9 using a plurality of resistor elements connected in series.

[0097] However, the data driving unit 30 and the grayscale voltage generating unit 35 are not limited to the above structure, and can be transformed into various structures to generate grayscale voltages Vg0~Vg255 from the gamma reference voltage VREF and output the pre-emphasis voltage Vpre and the data voltage Vdata based on the grayscale voltages Vg0~Vg255 and the data DATA.

[0098] Figure 4is a lookup table according to an embodiment of the present invention, Figure 5 This is a waveform diagram for explaining the pre-emphasis voltage and data voltage. Figure 6 The CIE 1931 (x, y) chromaticity diagram is a standard chromaticity diagram based on the standard color measurement system established by the International Commission on Illumination (CIE) in 1931.

[0099] First, refer to Figure 4 The vertical n columns of lookup table 15 represent image data values ​​for the current horizontal period, and the horizontal n-1 columns represent image data values ​​for the previous horizontal period. Data values ​​corresponding to the image data values ​​for the current horizontal period and the image data values ​​for the previous horizontal period represent pre-emphasis values. Furthermore, all data values ​​in lookup table 15 represent grayscale levels.

[0100] In the lookup table 15, the image data values ​​in the current horizontal period are the same as the image data values ​​in the previous horizontal period, and the data values ​​in the diagonal direction correspond to the case where the voltage level of the data signal does not change. The lower left end centered on the diagonal data values ​​corresponds to the case where the grayscale increases from a low grayscale to a high grayscale, and the upper right end centered on the diagonal direction corresponds to the case where the grayscale decreases from a high grayscale to a low grayscale.

[0101] Reference Figure 4 and Figure 5 The data driving unit 30 may supply a pre-emphasis voltage Vpre generated based on the pre-emphasis value to the data lines D1 to Dm during a first period t1 of the horizontal period 1H. Furthermore, the data driving unit 30 may supply a data voltage Vdata generated based on the image data value during a second period t2 of the horizontal period 1H. The data signal may include the pre-emphasis voltage Vpre and the data voltage Vdata.

[0102] Specifically, at a rising edge of the data signal, the pre-emphasis voltage Vpre has a higher voltage level than the data voltage Vdata.

[0103] The timing control unit 10 can determine the pre-emphasis grayscale value based on the lookup table 15 that records the pre-emphasis values ​​corresponding to the image data values ​​of the previous horizontal period and the image data values ​​of the current horizontal period. However, intermediate values ​​not recorded in the lookup table 15 can be determined by interpolation.

[0104] For example, when the image data value of the current horizontal period is 32 grayscales and the image data value of the previous horizontal period is 32 grayscales, the pre-emphasis value is determined to be 32 grayscales. Therefore, the pre-emphasis is not substantially driven.

[0105] When the image data value of the current horizontal period is 96 grayscales and the image data value of the previous horizontal period is 0 grayscales, the pre-emphasis value is determined to be 129 grayscales. That is, because the data voltage Vdata(n) of the current horizontal period is higher than the data voltage Vdata(n-1) of the previous horizontal period, pre-emphasis is driven so that the pre-emphasis voltage Vpre(n) of the current horizontal period has a voltage level higher than the data voltage Vdata(n). The pre-emphasis voltage Vpre(n) can be supplied to the data lines D1-Dm during the first period t1 of the current horizontal period, and the data voltage Vdata(n) can be supplied to the data lines D1-Dm during the second period t2.

[0106] According to one embodiment of the present invention, the display device 100 may include a plurality of screen modes. The display device 100 may change the color sense of the screen according to the set target color coordinates. The plurality of screen modes may include a first screen mode having a first target color coordinate, a second screen mode having a second target color coordinate, and a third screen mode having a third target color coordinate. For example, the first screen mode may be a standard mode (Standard Mode), the second screen mode may be a warm color mode (Warm Mode) having a red series color sense with a lower color temperature than the standard mode, and the third screen mode may be a cool color mode (Cool Mode) having a blue series color sense with a higher color temperature than the standard mode. At this time, the number of screen modes is exemplary, and for the convenience of the user, a more subdivided screen mode may be provided.

[0107] Each of the first target color coordinate, the second target color coordinate, and the third target color coordinate may be a target color coordinate for maintaining the white balance of the screen displayed by the display device 100 in each of the first screen mode, the second screen mode, and the third screen mode. The target color coordinate may be represented by a first coordinate and a second coordinate of rectangular coordinates. For example, in Figure 6 In the CIE 1931 (x, y) chromaticity diagram shown, the first coordinate can be the x-coordinate, and the second coordinate can be the y-coordinate. In this case, the curved outline of the outline corresponds to monochromatic light, and the wavelength of each monochromatic light is expressed in nanometers. Color temperature is primarily expressed in Kelvin, a standard unit. Longer wavelengths (i.e., closer to red) correspond to lower color temperatures, while shorter wavelengths (i.e., closer to blue) correspond to higher color temperatures.

[0108] According to one embodiment, the first and second coordinates of the second target color coordinates can be greater than the first and second coordinates of the first target color coordinates. Conversely, the first and second coordinates of the third target color coordinates can be smaller than the first and second coordinates of the first target color coordinates. For example, the first target color coordinates for the standard mode can be (0.284, 0.286), the second target color coordinates for the warm color mode can be (0.313, 0.329), and the third target color coordinates for the cool color mode can be (0.272, 0.278). In this case, the color coordinates of the input data DATA (or the reference color coordinates without white balancing) can be (0.292, 0.302).

[0109] In other words, the second target color coordinates of the second screen mode (or warm color mode) can be located approximately to the upper right of the first target color coordinates of the first screen mode (or standard mode) on the CIE 1931 (x, y) chromaticity diagram. Conversely, the third target color coordinates of the third screen mode (or cool color mode) can be located approximately to the lower left of the first target color coordinates of the first screen mode (or standard mode) on the CIE 1931 (x, y) chromaticity diagram. Accordingly, if the user changes the screen mode of the display device 100 from the standard mode to the warm color mode, the screen can emphasize red or yellow. Conversely, if the background color of the display device 100 is adjusted to a cool color, the screen can emphasize blue.

[0110] Figures 7a to 7c This is a diagram for explaining a phenomenon in which white balance is distorted when one screen mode is selected from a plurality of screen modes. Figure 8 is a graph showing measured color coordinates according to grayscale measurement in one screen mode selected from a plurality of screen modes.

[0111] Reference Figure 1 and Figures 7a to 7c In order to stably display an image in the pixel unit 50, it is necessary to stably supply the data signal to the pixel PX within a predetermined time (i.e., a period during which the scan signal is supplied) of 1H. However, due to an increase in resolution and a larger panel, the data signal may not be fully charged to a desired voltage (target voltage) during the period during which the scan signal is supplied.

[0112] For example, when the image data value changes from grayscale 0 to grayscale 96, if the time period of 1H for supplying the scanning signal is not sufficiently ensured, Figure 7a As shown, it may happen that the data signal does not reach the voltage corresponding to 96 grayscale, but only reaches the voltage corresponding to 92 grayscale which is 4 grayscales lower than 96 grayscale.

[0113] In addition, when the display device 100 provides multiple screen modes, in order to maintain the white balance of the screen, the target color coordinates can be applied differently according to the screen mode. That is, when the display device 100 changes the screen mode, the data DATA used to display the same image data can be changed.

[0114] For example, Figure 7b As shown in FIG. 1 , the image data displayed at 96 grayscales before the screen mode change may be displayed at 104 grayscales after the screen mode change is applied with white balance. In this case, the data signal may not reach the voltage corresponding to 104 grayscales but only reach the voltage corresponding to 92 grayscales, which is 12 grayscales lower than 104 grayscales. This means that Figure 7a Compared to the embodiment shown, the supply of data DATA required for displaying image data is even more insufficient.

[0115] On the contrary, Figure 7c As shown in FIG. 1 , it is possible that image data displayed at 96 grayscales before the screen mode is changed is displayed at 88 grayscales after the white balance is applied due to the screen mode change. In this case, it is possible that the data signal exceeds the voltage corresponding to 88 grayscales and reaches the voltage corresponding to 92 grayscales, which is 4 grayscales higher than 88 grayscales. This means that Figure 7a Compared to the illustrated embodiment, data DATA required for displaying image data is supplied in excess.

[0116] As described above, when the screen mode of the display device 100 is changed, in the case where the data DATA for displaying image data is not properly compensated, as shown in FIG. Figure 8 As shown, the linearity of the color coordinates may be destroyed.

[0117] Figure 8 is a graph showing measured color coordinates of the display device 100 in which the pre-emphasis value is not compensated when the screen mode is changed.

[0118] If the measured color coordinates are observed, it can be confirmed that the difference between the target color coordinates and the measured color coordinates is large in the low grayscale area. For example, the first target color coordinates of the first screen mode may be (0.284, 0.286). At this time, the maximum allowable coordinate Max_x of the first coordinate (or, x coordinate) of the first target color coordinate may be approximately 0.288, the minimum allowable coordinate (Min_x) of the first coordinate (or, x coordinate) of the first target color coordinate is approximately 0.278, the maximum allowable coordinate Max_y of the second coordinate (or, y coordinate) of the first target color coordinate is approximately 0.291, and the minimum allowable coordinate Min_y of the second coordinate (or, y coordinate) of the first target color coordinate is approximately 0.281. From Figure 8The graph shows that the measured color coordinates (Standard_x, Standard_y) are distorted in white balance relative to the target color coordinates in the grayscale range of 0 to 130, which exceeds the maximum allowable coordinates (Max_x, Max_y) and the minimum allowable coordinates (Min_x, Min_y).

[0119] Table 1 below shows differences between target color coordinates according to screen modes and measured color coordinates measured at a specific grayscale (eg, 32 grayscale) according to an embodiment.

[0120] [Table 1]

[0121]

[0122]

[0123] With reference to Table 1, it can be confirmed that when the lookup table corresponding to the color coordinates of the input data DATA is directly applied in the first screen mode, the second screen mode, and the third screen mode, differences occur between the target color coordinates of each screen mode and the measured color coordinates. Figure 8 As shown, at 32 grayscales, the measured color coordinates of the first screen mode (or standard mode) are (0.295, 0.297), and thus have a difference from the first target color coordinates (0.284, 0.286) equivalent to the color coordinates (0.011, 0.011).

[0124] Similarly, the measured color coordinates for the second screen mode (or warm color mode) are (0.342, 0.372), resulting in a difference of (0.029, 0.043) from the second target color coordinates (0.313, 0.329). Since the measured color coordinates for the third screen mode (or cool color mode) are (0.260, 0.270), they differ from the third target color coordinates (0.272, 0.278) by (-0.012, -0.008). Without compensating for this color coordinate difference, the white balance of the display device 100 is distorted.

[0125] Figure 9 According to an embodiment Figure 1 The detailed structure of the timing control unit is shown in FIG. Figures 10a to 10c is a lookup table created according to a screen mode according to an embodiment.

[0126] Reference Figure 9 and Figures 10a to 10c The timing control unit 10 may include a lookup table 15_T and a lookup table selection unit 16 .

[0127] According to an embodiment of the present invention, the timing control unit 10 may calculate the data DATA compensated for the difference in color coordinates, and provide the calculated data DATA to the data driving unit 30 .

[0128] For example, when the first screen mode is selected, the timing control unit 10 may determine the difference between the first target color coordinates and the measured color coordinates according to the grayscale, calculate a first compensation value using the difference, and add the first compensation value to the pre-emphasis value. Accordingly, the timing control unit 10 may provide the data DATA modified (or compensated) according to the first screen mode to the data driving unit 30.

[0129] Similarly, the timing control unit 10 can calculate the difference between the second target color coordinates and the measured color coordinates according to the grayscale when the second screen mode is selected, and use the difference value to calculate the second compensation value, and add the second compensation value to the pre-emphasis value, thereby providing the data DATA changed (or compensated) corresponding to the second screen mode to the data driving unit 30.

[0130] Furthermore, the timing control unit 10 can calculate the difference between the third target color coordinates and the measured color coordinates according to the grayscale when the third screen mode is selected, and use the difference value to calculate the third compensation value, and add the third compensation value to the pre-emphasis value, thereby providing the data DATA changed (or compensated) corresponding to the third screen mode to the data driving unit 30.

[0131] The second compensation value for the second screen mode (or warm color mode) may be greater than or equal to the first compensation value for the first screen mode (or standard mode), and the third compensation value for the third screen mode (or cool color mode) may be less than or equal to the first compensation value for the first screen mode (or standard mode). For example, the first to third compensation values ​​may be calculated using the following mathematical formula 1. The first compensation value calculated using mathematical formula 1 may be 11, the second compensation value may be 57, and the third compensation value may be -4. In this case, the first to third compensation values ​​represent grayscale levels.

[0132] [Mathematical formula 1]

[0133] Compensation value = (Δy / 0.001) + (Δy-Δx) / 0.001

[0134] (At this time, Δx is the difference between the first coordinate of the target coordinate and the first coordinate of the measured coordinate, and Δy is the difference between the second coordinate of the target coordinate and the measured coordinate)

[0135] However, when calculating the first to third compensation values, using Mathematical Formula 1 is exemplary, and the method of calculating the first to third compensation values ​​may be variously implemented in an experimental or statistical manner according to debugging results of the test display device 100 .

[0136] According to an embodiment of the present invention, the timing control section 10 may determine the pre-emphasis grayscale value based on the lookup tables 15_1 to 15_n selected by the selection section 16 from among the plurality of lookup tables 15_T.

[0137] The lookup table 15_T may include lookup tables 15_1 to 15_n for each of the screen modes. For example, the lookup table 15_1 may include a first lookup table 15_1 for a first screen mode (or standard mode), a second lookup table 15_2 for a second screen mode (or warm color mode), a third lookup table 15_3 for a third screen mode (or cool color mode), and an nth lookup table 15_n for an nth screen mode. Figure 4 The illustrated lookup table 15 may be a reference lookup table corresponding to the color coordinates of the input data DATA (or reference color coordinates to which white balance is not applied).

[0138] The pre-emphasis values ​​included in the second lookup table 15_2 may be greater than or equal to the pre-emphasis values ​​included in the corresponding first lookup table 15_1 , and the pre-emphasis values ​​included in the third lookup table 15_3 may be less than or equal to the pre-emphasis values ​​included in the corresponding first lookup table 15_1 .

[0139] Reference Figure 4 and Figures 10a to 10c , the vertical n columns of lookup tables 15, 15_1, 15_2, and 15_3 represent image data values ​​for the current horizontal time period, and the horizontal n-1 columns represent image data values ​​for the previous horizontal time period. Comparing image data values ​​corresponding to the same rows and columns, the first lookup table 15_1 is approximately 11 grayscales larger than the reference lookup table 15, the second lookup table 15_2 is approximately 57 grayscales larger than the reference lookup table 15, and the third lookup table 15_3 is approximately -4 grayscales larger than the reference lookup table 15. This means that each of the first to third compensation values ​​calculated using Mathematical Formula 1 is added to the reference lookup table 15.

[0140] The timing control section 10 may receive a lookup table selection signal SS through the lookup table selection section 16 and provide the lookup tables 15_1 ˜ 15 — n corresponding to the lookup table selection signal SS to the data driving section 30 .

[0141] According to one embodiment, the lookup table selection signal SS may be generated by an input of a user of the display device 100. However, the present invention is not limited thereto and may sense the surrounding environment through various sensors mounted on the display device 100. An application processor (not shown) of the display device 100 may select one of a plurality of screen modes based on the sensed information and may generate a lookup table selection signal SS according to the screen mode.

[0142] Figure 11 is a graph showing measured color coordinates of the display device 100 in which the pre-emphasis value is compensated when the screen mode is changed.

[0143] According to an embodiment of the present invention, the timing control unit 10 can provide data whose pre-emphasis value is changed according to a screen mode selected from a plurality of screen modes with different target color coordinates to the data driving unit 30. Therefore, it is expected that the white balance effect can be maintained across the entire grayscale.

[0144] If you observe Figure 11 The measured color coordinates shown can be confirmed to be consistent with Figure 8 Compared with the measured color coordinates shown in FIG. 1 , in the low grayscale area, the measured color coordinates (Standard_x, Standard_y) are also within the range of the maximum allowable coordinates (Max_x, Max_y) and the minimum allowable coordinates (Min_x, Min_y).

[0145] Figure 12 is a flowchart illustrating a method for driving a display device according to an embodiment of the present invention.

[0146] Reference Figure 12 In a method for driving a display device 100 according to an embodiment of the present invention, first, the timing control unit 10 compares the image data value of a previous horizontal period with the image data value of a current horizontal period (S10). Specifically, the timing control unit 10 may compare the image data value of the previous horizontal period with the image data value of the current horizontal period to determine a pre-emphasis value corresponding to the current horizontal period.

[0147] In one embodiment, the timing control unit 10 may determine the pre-emphasis grayscale value based on a lookup table 15 recording pre-emphasis values ​​corresponding to image data values ​​of a previous horizontal period and image data values ​​of a current horizontal period.

[0148] The timing control unit 10 provides data DATA including a pre-emphasis value and an image data value to the data driving unit 30 (S20). The timing control unit 10 compensates the image data input from the outside to an image suitable for displaying an image in the pixel unit 50, and provides the compensated data DATA to the data driving unit 30. The timing control unit 10 may change a portion of the image data value to the determined pre-emphasis value.

[0149] The timing control unit 10 determines whether the screen mode of the display device 100 has been changed by receiving a lookup table selection signal SS (S30). According to one embodiment, the lookup table selection signal SS may be generated by an input from a user of the display device 100. However, the present invention is not limited thereto. Various sensors mounted on the display device 100 may sense the surrounding environment. An application processor (not shown) of the display device 100 may select a screen mode from a plurality of screen modes based on the sensed information and may generate a lookup table selection signal SS according to the screen mode.

[0150] In this case, the multiple screen modes may include a first screen mode having a first target color coordinate, a second screen mode having a second target color coordinate, and a third screen mode having a third target color coordinate. For example, the first screen mode may be a standard mode, the second screen mode may be a warm mode having a reddish color temperature lower than that of the standard mode, and the third screen mode may be a cool mode having a blued color temperature higher than that of the standard mode.

[0151] When it is determined in step S30 that the screen mode has been changed, the timing control part 10 provides data including the compensated pre-emphasis value and the image data value corresponding to the changed screen mode to the data driving part 30 ( S40 ).

[0152] According to an embodiment of the present invention, the timing control unit 10 may calculate the data DATA compensated for the difference in color coordinates, and provide the calculated data DATA to the data driving unit 30 .

[0153] For example, the timing control unit 10 can determine the difference between the target color coordinates and the measured color coordinates according to the grayscale when a screen mode is selected, calculate a compensation value using the difference, and add the compensation value to the pre-emphasis value. Therefore, the timing control unit 10 can provide the data DATA modified (or compensated) according to the selected screen mode to the data driving unit 30.

[0154] For example, the compensation value may be calculated using the above-mentioned Mathematical Formula 1. In this case, the compensation value represents a gray scale level.

[0155] The timing control part 10 supplies data having a pre-emphasis value changed in accordance with one screen mode selected from a plurality of screen modes having different target color coordinates to the data driving part 30 , thereby maintaining white balance across all grayscales.

[0156] Next, the data driving part 30 supplies the pre-emphasis voltage to the data lines D1 to Dm during a first period, and supplies the data voltage during a second period ( S50 ).

[0157] The data driving part 30 may receive the gamma reference voltage VREF from the gamma reference voltage supply part 20 .

[0158] The data driving unit 30 may supply a pre-emphasis voltage generated based on a pre-emphasis value and a gamma reference voltage VREF to the data lines D1 to Dm during a first period of the horizontal period. Furthermore, the data driving unit 30 may supply a data voltage generated based on an image data value and the gamma reference voltage VREF during a second period of the horizontal period. The data signal may include the pre-emphasis voltage and the data voltage.

[0159] Although the present invention has been described above with reference to the embodiments, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the invention as described in the claims.

Claims

1. A display device comprising: a timing control unit providing data including a pre-emphasis value and an image data value; as well as a data driving unit that supplies a pre-emphasis voltage generated based on the pre-emphasis value to the data line during a first period of a horizontal period, and supplies a data voltage generated based on the image data value to the data line during a second period of the horizontal period, The timing control unit provides data for changing the pre-emphasis value in accordance with a screen mode selected from a plurality of screen modes having different target color coordinates. The timing control unit, when each of the multiple screen modes is selected, calculates a difference between the target color coordinates corresponding to the selected screen mode and the measured color coordinates according to the grayscale, calculates a compensation value using the difference value, and adds the compensation value to the pre-emphasis value.

2. The display device according to claim 1, wherein The plurality of screen modes include a first screen mode having first target color coordinates, a second screen mode having second target color coordinates, and a third screen mode having third target color coordinates.

3. The display device according to claim 2, wherein: The first target color coordinates to the third target color coordinates are defined by first and second coordinates of rectangular coordinates, the first and second coordinates of the second target color coordinates are greater than the first and second coordinates of the first target color coordinates, and the first and second coordinates of the third target color coordinates are smaller than the first and second coordinates of the first target color coordinates.

4. The display device according to claim 2, wherein The timing control section compares the image data value of a previous horizontal period with the image data value of a current horizontal period to determine the pre-emphasis value corresponding to the current horizontal period.

5. The display device according to claim 4, wherein The timing control unit obtains a first difference between the first target color coordinates and the measured color coordinates according to the grayscale when the first screen mode is selected, calculates a first compensation value using the first difference value, and adds the first compensation value to the pre-emphasis value. The timing control unit obtains a second difference value between the second target color coordinates and the measured color coordinates according to the grayscale when the second screen mode is selected, calculates a second compensation value using the second difference value, and adds the second compensation value to the pre-emphasis value. The timing control section obtains a third difference value between the third target color coordinates and the measured color coordinates according to grayscale when the third screen mode is selected, calculates a third compensation value using the third difference value, and adds the third compensation value to the pre-emphasis value. The display device according to claim 5 , wherein: The first to third compensation values ​​are calculated using the following mathematical formula 1: [Mathematical formula 1] Compensation value = (Δy / 0.001) + (Δy-Δx) / 0.001 Wherein, Δx is the difference between the first coordinate of the target coordinate and the first coordinate of the measured coordinate, and Δy is the difference between the second coordinate of the target coordinate and the second coordinate of the measured coordinate.

7. The display device according to claim 5, wherein: The second compensation value is greater than or equal to the first compensation value, and the third compensation value is less than or equal to the first compensation value.

8. The display device according to claim 2, wherein: The timing control section determines the pre-emphasis value based on a lookup table in which the pre-emphasis values ​​corresponding to the image data value of a previous horizontal period and the image data value of a current horizontal period are recorded.

9. The display device according to claim 8, wherein The lookup table includes a first lookup table corresponding to the first screen mode, a second lookup table corresponding to the second screen mode, and a third lookup table corresponding to the third screen mode.

10. The display device according to claim 9, wherein The pre-emphasis values ​​included in the second lookup table are greater than or equal to the corresponding pre-emphasis values ​​included in the first lookup table, and the pre-emphasis values ​​included in the third lookup table are less than or equal to the corresponding pre-emphasis values ​​included in the first lookup table.

11. The display device according to claim 1, wherein Also includes: Gamma reference voltage supply unit, supplies gamma reference voltage, The gamma reference voltages include a lowest gamma reference voltage corresponding to a lowest grayscale value and a highest gamma reference voltage corresponding to a highest grayscale value.

12. The display device according to claim 11, wherein The data driving unit includes a grayscale voltage generating unit that divides the gamma reference voltage to generate a plurality of grayscale voltages.

13. The display device according to claim 12, wherein: The data driving unit selects one grayscale voltage corresponding to the pre-emphasis value from the plurality of grayscale voltages to generate the pre-emphasis voltage, and selects one grayscale voltage corresponding to the image data value from the plurality of grayscale voltages to generate the data voltage.

14. The display device according to claim 1, wherein Also includes: A scan driver that supplies scan signals via scan lines; as well as The pixel portion includes a plurality of pixels connected to the scan lines and the data lines.

Images