Display device and driving method thereof

Abstract

The present invention provides a display device and a driving method thereof. The display device includes: a grayscale conversion unit that adds a compensation grayscale to an input grayscale to provide an output grayscale; a data driving unit that provides a data voltage corresponding to the output grayscale; and a pixel unit including a plurality of pixels that receive the data voltage. The grayscale conversion unit includes: a voltage range conversion unit that converts the input grayscale into a converted grayscale within a voltage range; and a compensation grayscale calculation unit that calculates the compensation grayscale based on the converted grayscale.

Description

Technical Field

[0001] The present invention relates to a display device and a driving method thereof. Background Art

[0002] With the advancement of information technology, the importance of display devices as a medium between users and information has attracted much attention. In response, the use of display devices such as liquid crystal display devices (LCDs), organic light emitting display devices (OLEDs), and plasma display devices is increasing.

[0003] The data driving unit of the display device can supply data voltages to each pixel, causing the pixel to emit light at a brightness based on the data voltage, thereby displaying an image. In this case, each pixel can share a smaller number of data lines than the number of pixels and can receive the data voltages in a time-division manner.

[0004] At this time, the data voltage of each pixel may be affected by the data voltage of the adjacent pixel sharing the same data line. To solve this problem, a method of comparing the grayscales of adjacent pixels to calculate a compensated grayscale has been proposed.

[0005] However, the compensated grayscale calculated in this way is non-linear, and therefore there is a problem in that it is difficult to apply various gains required according to the structure and driving method of the display device. Summary of the Invention

[0006] The problem to be solved is to provide a display device and a driving method thereof that can calculate a linear compensation value within a voltage range and easily adapt various gains required according to the structure and driving method of the display device.

[0007] A display device according to an embodiment of the present invention includes: a grayscale conversion unit that adds a compensation grayscale to an input grayscale to provide an output grayscale; a data driving unit that provides a data voltage corresponding to the output grayscale; and a pixel unit that includes a plurality of pixels that receive the data voltage, wherein the grayscale conversion unit includes: a voltage range conversion unit that converts the input grayscale into a conversion grayscale of a voltage range; and a compensation grayscale calculation unit that calculates the compensation grayscale based on the conversion grayscale.

[0008] Alternatively, the grayscale conversion unit further includes a memory configured to output a previous converted grayscale corresponding to a previous pixel row.

[0009] Alternatively, the plurality of pixels may be respectively connected to a data line located in the first direction based on each of the pixels.

[0010] Alternatively, the grayscale conversion unit further includes a memory configured to output a previous converted grayscale corresponding to two previous pixel rows.

[0011] It may be that the plurality of pixels are divided into a plurality of first pixels and a plurality of second pixels, the plurality of first pixels are respectively connected to data lines located in a first direction based on the respective first pixels, and the plurality of second pixels are respectively connected to data lines located in a second direction based on the respective second pixels.

[0012] Alternatively, the display device further includes a data distribution unit connected to the data driving unit via a plurality of data output lines and connected to the plurality of pixels via a plurality of data lines, wherein the number of the plurality of data output lines is less than the number of the plurality of data lines.

[0013] It can be that the compensation grayscale calculation unit includes: a lookup table, which records compensation values ​​corresponding to a part of the previous transformation grayscale and a part of the transformation grayscale, and the compensation grayscale calculation unit interpolates the compensation values ​​for a part of the multiple pixels to calculate the first interpolated values.

[0014] The compensated grayscale calculation unit may calculate a second interpolation value by interpolating the first interpolation value for another portion of the pixels among the plurality of pixels.

[0015] The compensated grayscale calculation unit may convert the second interpolation value into a grayscale range and provide the converted value as the compensated grayscale.

[0016] It may be that the grayscale conversion unit further includes: a maximum brightness gain providing unit, which provides a maximum brightness gain based on the maximum brightness; the compensation grayscale calculation unit scales the second interpolation according to the maximum brightness gain, and converts the scaled second interpolation into a grayscale range to provide it as the compensation grayscale.

[0017] The maximum luminance gain providing unit may increase the maximum luminance gain as the maximum luminance increases.

[0018] It may be that the grayscale conversion unit further includes: a connection gain providing unit, which provides a connection gain for the first pixel, and the compensation grayscale calculation unit scales the second interpolation according to the connection gain, and converts the scaled second interpolation into a grayscale range to provide it as the compensation grayscale.

[0019] The connection gain providing unit may not provide a connection gain for the second pixel.

[0020] It may be that the grayscale conversion unit further includes: a regional gain providing unit, which provides a regional gain based on the position of the pixel, and the compensation grayscale calculation unit scales the second interpolation according to the regional gain, and converts the scaled second interpolation into a grayscale range to provide it as the compensation grayscale.

[0021] It may be that the pixel portion is divided into a first area, a second area, and a third area, the first area includes a plurality of pixels at a first density, the second area and the third area include a plurality of pixels at a second density higher than the first density, the pixels of the second area and the pixels of the first area are connected to the same data line, and the regional gain providing unit provides a first regional gain to the pixels of the first area, and provides a second regional gain to the pixels of the second area.

[0022] A driving method for a display device involved in one embodiment of the present invention may include: a step of converting an input grayscale into a converted grayscale within a voltage range; a step of calculating a compensated grayscale based on the converted grayscale; a step of adding the compensated grayscale to the input grayscale to provide an output grayscale; and a step of providing a data voltage corresponding to the output grayscale to multiple pixels.

[0023] It can be that the driving method also includes the following steps: referring to a lookup table, interpolating the compensation value for a part of the multiple pixels to calculate a first interpolation value, wherein the lookup table records the compensation values ​​corresponding to a part of the previous conversion grayscale corresponding to two previous pixel rows and a part of the conversion grayscale.

[0024] Alternatively, the driving method further includes the following step: interpolating the first interpolation value for another portion of the pixels to calculate a second interpolation value.

[0025] Alternatively, the driving method further includes the step of providing the second interpolation as the compensated grayscale.

[0026] Alternatively, the driving method further includes the steps of scaling the second interpolation value according to a maximum brightness gain that increases as the maximum brightness increases, and converting the scaled second interpolation value into a grayscale range to provide the compensated grayscale.

[0027] (Effects of the Invention)

[0028] The display device and the driving method thereof according to the present invention can calculate a linear compensation value within a voltage range, thereby easily adapting various gains required according to the structure and driving method of the display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A diagram for explaining a display device according to an embodiment of the present invention.

[0030] Figure 2 This is a diagram for explaining a pixel according to an embodiment of the present invention.

[0031] Figure 3 and Figure 4 This is a diagram for explaining a pixel unit and a data allocation unit according to an embodiment of the present invention.

[0032] Figure 5 This is a diagram for explaining a grayscale conversion unit according to an embodiment of the present invention.

[0033] Figure 6 This is a diagram for explaining a voltage range conversion unit according to an embodiment of the present invention.

[0034] Figure 7 and Figure 8 This is a diagram for explaining a compensation grayscale calculation unit according to an embodiment of the present invention.

[0035] Figure 9 and Figure 10 This is a diagram for explaining a maximum brightness gain providing unit according to an embodiment of the present invention.

[0036] Figure 11 and Figure 12 This is a diagram for explaining a connection gain providing unit according to an embodiment of the present invention.

[0037] Figure 13 and Figure 14 This is a diagram for explaining a regional gain providing unit according to an embodiment of the present invention.

[0038] Figure 15 It is a diagram for explaining a grayscale conversion unit according to another embodiment of the present invention.

[0039] Figure 16 It is a diagram for explaining a display device according to another embodiment of the present invention.

[0040] Figure 17 This is a diagram for explaining a pixel portion according to another embodiment of the present invention. DETAILED DESCRIPTION

[0041] Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. The present invention can be implemented in various forms and is not limited to the embodiments described herein.

[0042] In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are given the same reference numerals throughout the specification. Therefore, the reference numerals previously described may be used in other drawings.

[0043] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the sake of convenience of explanation, and the present invention is not necessarily limited to the illustrated cases. In the drawings, the thickness is exaggerated to clearly illustrate each layer and region.

[0044] Figure 1 A diagram for explaining a display device according to an embodiment of the present invention.

[0045] Reference Figure 1 A display device 10 according to an embodiment of the present invention may include a timing control unit 11 , a data driving unit 12 , a scan driving unit 13 , a pixel unit 14 , a grayscale conversion unit 15 , and a data distribution unit 16 .

[0046] The timing control unit 11 may receive input grayscale and control signals for each frame (or input image) from an external processor and provide control signals suitable for their specifications to the data driver 12, scan driver 13, etc. for frame display.

[0047] The grayscale conversion unit 15 can add a compensation grayscale to the input grayscale to provide an output grayscale. The timing control unit 11 can provide this output grayscale to the data driver 12. The grayscale conversion unit 15 can be formed as an integrated IC (integrated chip) with the timing control unit 11 or the data driver 12, or the grayscale conversion unit 15 can be formed as a separate independent IC. Alternatively, the grayscale conversion unit 15 can also be implemented by software in the timing control unit 11 or the data driver 12.

[0048] The data driver 12 can provide data voltages corresponding to the output grayscale. For example, the data driver 12 can use the output grayscale and control signals to generate data voltages to be provided to the data output lines DO1, DO2, ..., DOr. For example, the data driver 12 can sample the output grayscale using a clock signal and apply the data voltages corresponding to the output grayscale to the data output lines DO1 to DOr in units of pixel rows. A pixel row can refer to a combination of multiple pixels connected to a scan line. r can be an integer greater than 0.

[0049] The data distribution unit 16 can be connected to the data driving unit 12 via data output lines DO1-DOr, and can be connected to each pixel via data lines DL1, DL2, DL3, ..., DLn. n can be an integer greater than r. The data distribution unit 16 can be a demultiplexer. The data distribution unit 16 can selectively connect the data output lines DO1-DOr to the data lines DL1-DLn. The data lines DL1-DLn can receive data voltages from the connected data output lines DO1-DOr.

[0050] The scan driving unit 13 may receive a clock signal, a scan start signal, etc. from the timing control unit 11 , and generate scan signals to be provided to the scan lines SL1 , SL2 , SL3 , ..., SLm. m may be an integer greater than 0.

[0051] The scan driver 13 sequentially supplies scan signals with on-level pulses to the scan lines SL1 to SLm. The scan driver 13 can be implemented as a shift register and include multiple scan driver stages. The scan driver 13 generates scan signals by sequentially transmitting a scan start signal, which is in the form of an on-level pulse, to the next scan driver stage under the control of a clock signal.

[0052] The pixel portion 14 includes a plurality of pixels that receive data voltages. Each pixel PXij can be connected to a corresponding data line and a scan line. i and j can be integers greater than 0. The pixel PXij can mean a pixel in which a scan transistor is connected to the i-th scan line and the j-th data line. Each pixel can be connected to a first power line ELVDDL and a second power line ELVSSL (see Figure 2 ).

[0053] Figure 2 This is a diagram for explaining a pixel according to an embodiment of the present invention.

[0054] Reference Figure 2 The pixel PXij may be a pixel that emits light of the first color. The pixel that emits light of the second color or the third color includes substantially the same structure as the pixel PXij except for the light emitting diode LD, and therefore repeated description is omitted.

[0055] For example, the first color may be one of red, green, and blue, the second color may be one of red, green, and blue other than the first color, and the third color may be the remaining color of red, green, and blue other than the first color and the second color. Alternatively, magenta, cyan, and yellow may be used as the first to third colors instead of red, green, and blue.

[0056] The pixel PXij may include a plurality of transistors T1 , T2 , a storage capacitor Cst1 , and a light emitting diode LD.

[0057] In this embodiment, the case where the transistors T1 and T2 are P-type transistors (eg, PMOS) is shown, but those skilled in the art should be able to construct a pixel circuit with the same function using N-type transistors (eg, NMOS).

[0058] The transistor T2 has a gate electrode connected to the scan line SLi, a first electrode connected to the data line DLj, and a second electrode connected to the gate electrode of the transistor T1. The transistor T2 can be named a scan transistor.

[0059] The transistor T1 has a gate electrode connected to the second electrode of the transistor T2, a first electrode connected to the first power line ELVDDL, and a second electrode connected to the anode of the light emitting diode LD. The transistor T1 can be referred to as a driving transistor.

[0060] The storage capacitor Cst1 is connected to the first electrode and the gate electrode of the transistor T1 .

[0061] The anode of the light-emitting diode LD is connected to the second electrode of the transistor T1, and the cathode is connected to the second power supply line ELVSSL. The light-emitting diode LD can be an element that emits light of a wavelength corresponding to the first color. The light-emitting diode LD can be composed of an organic light-emitting diode or an inorganic light-emitting diode such as a micro-LED or a quantum dot light-emitting diode. In addition, the light-emitting diode LD can also be a light-emitting element composed of a composite of organic and inorganic substances. In this embodiment, only one light-emitting diode LD is shown, but multiple sub-light-emitting diodes can be connected in series, in parallel, or in series and parallel to replace the light-emitting diode LD.

[0062] When a scanning signal of a conduction level (low level) is supplied to the gate electrode of the transistor T2 via the scanning line SLi, the transistor T2 is connected to the data line DLj and the first electrode of the energy storage capacitor Cst1. Therefore, a voltage corresponding to the difference between the data voltage applied via the data line DLj and the first power supply voltage ELVDD is written into the energy storage capacitor Cst1. Figure 2 In FIG, “ELVSS” represents the second power supply voltage.

[0063] Transistor T1 allows a drive current, determined by the voltage written to storage capacitor Cst1, to flow from the first power line ELVDDL to the second power line ELVSSL. The light-emitting diode LD emits light at a brightness corresponding to the drive current. The light-emitting diode LD of each pixel can be connected between the common first power line ELVDDL and the second power line ELVSSL.

[0064] Figure 3 and Figure 4 This is a diagram for explaining a pixel unit and a data allocation unit according to an embodiment of the present invention.

[0065] Reference Figure 3 The data distribution unit 16 may include first transistors MA1, MA2, MA3, MA4, MA5, MA6, MA7, and MA8, and second transistors MB1, MB2, MB3, MB4, MB5, MB6, MB7, and MB8. The gate electrodes of the first transistors MA1 to MA8 may be connected to the first control line CLA, the first electrodes may be connected to the data output lines DO1 to DO8, and the second electrodes may be connected to the first data lines DL2, DL3, DL6, DL7, DL10, D11, DL14, and DL15 (hereinafter referred to as the first data lines DL2 to DL15). The gate electrodes of the second transistors MB1 to MB8 may be connected to the second control line CLB, the first electrodes may be connected to the data output lines DO1 to DO8, and the second electrodes may be connected to the second data lines DL1, DL4, DL5, DL8, DL9, DL12, DL13, and DL16 (hereinafter referred to as the second data lines DL1 to DL16). The number of first transistors MA1 to MA8 may be the same as the number of second transistors MB1 to MB8. In addition, the number of first data lines DL2 to DL15 may be the same as the number of second data lines DL1 to DL16. The data distribution unit 16 may be a demultiplexer with an input-to-output ratio of 1:2.

[0066] The on-periods of the first transistors MA1 to MA8 and the on-periods of the second transistors MB1 to MB8 may not overlap with each other. The timing control unit 11 may provide a control signal of an on-level to the first control line CLA and the second control line CLB so that the first transistors MA1 to MA8 and the second transistors MB1 to MB8 are alternately turned on (refer to Figure 4 ).

[0067] For example, the pixel portion 14 may include pixels PX12, PX13, PX16, PX17, PX110, PX111, PX114, PX115, PX21, PX24, PX25, PX28, PX29, PX212, PX213, PX216, PX32, PX33, PX36, PX37, PX310, PX311, PX314, PX315, PX41, PX44, PX45, PX48, PX49, PX412, PX413, and PX416 arranged in a pentile structure.

[0068] Pixels PX12 to PX115 and PX32 to PX315 connected to the first scan line SL1 and the third scan line SL3 can be connected to the first data lines DL2 to DL15. Pixels PX21 to PX216 and PX41 to PX416 connected to the second scan line SL2 and the fourth scan line SL4 can be connected to the second data lines DL1 to DL16. In this embodiment, odd-numbered pixel rows are connected to the first data lines DL2 to DL15, and even-numbered pixel rows are connected to the second data lines DL1 to DL16. In other embodiments, even-numbered pixel rows can be connected to the first data lines DL2 to DL15, and odd-numbered pixel rows can be connected to the second data lines DL1 to DL16.

[0069] In odd-numbered pixel rows, each pixel may be configured to repeat red (e.g., pixel PX12), green (e.g., pixel PX13), blue (e.g., pixel PX16), and green (e.g., pixel PX17) in sequence along the extension direction of the scan line. The extension direction of the scan line may be the first direction DR1 or the second direction DR2. At this time, in even-numbered pixel rows, each pixel may be configured to repeat blue (e.g., pixel PX21), green (e.g., pixel PX24), red (e.g., pixel PX25), and green (e.g., pixel PX28) in sequence along the extension direction of the scan line. As described above, odd and even numbers are interchangeable.

[0070] Pixels of the same color are connected to each data line. For example, blue pixels PX21 and PX41 are connected to data line DL1. Red pixels PX12 and PX32 are connected to data line DL2. Green pixels PX13 and PX33 are connected to data line DL3. Data lines DL1-DL16 may extend in a third direction DR3. The third direction DR3 may be orthogonal to the first direction DR1 or the second direction DR2.

[0071] Pixels PX12 to PX416 may be divided into first pixels PX13, PX17, PX111, PX115, PX21, PX25, PX29, PX213, PX33, PX37, PX311, PX315, PX41, PX45, PX49, and PX413 (hereinafter referred to as first pixels PX13 to PX413) and second pixels PX12, PX16, PX110, PX114, PX24, PX28, PX212, PX216, PX32, PX36, PX310, PX314, PX44, PX48, PX412, and PX416 (hereinafter referred to as second pixels PX12 to PX416). The first pixels PX13 to PX413 may be connected to data lines located in a first direction DR1 based on the first pixels PX13 to PX413, respectively. The second pixels PX12 to PX416 may be connected to data lines located in a second direction DR2 based on the second pixels PX12 to PX416, respectively. The first direction DR1 and the second direction DR2 may be opposite to each other.

[0072] When the pixels of the pixel unit 14 are arranged in rows and columns, the first pixels PX13 to PX413 and the second pixels PX12 to PX416 may be alternately arranged in the row direction (first direction DR1 or second direction DR2 ) and the column direction (third direction DR3 ).

[0073] Reference Figure 4 The scan drive unit 13 can sequentially supply on-level scan signals to the scan lines SL1, SL2, SL3, and SL4. When supplying an on-level scan signal to the scan line SL1, the data voltage DV12 for the pixel PX12 can be supplied to the data line DL2. When supplying an on-level scan signal to the scan line SL2, the data voltage DV21 for the pixel PX21 can be supplied to the data line DL1. When supplying an on-level scan signal to the scan line SL3, the data voltage DV32 for the pixel PX32 can be supplied to the data line DL2. When supplying an on-level scan signal to the scan line SL4, the data voltage DV41 for the pixel PX41 can be supplied to the data line DL1.

[0074] As the pixel unit 14 becomes higher in resolution, the period during which the data voltage can be written to each pixel tends to decrease. As a result, there may be a situation where the desired data voltage cannot be fully written to the pixel. For example, suppose the data voltage DV32 is greater than the data voltage DV12. In this case, the greater the difference between the data voltage DV32 and the data voltage DV12, the larger the data voltage DV32 is provided, so that compensation can be performed so that the desired data voltage DV32 is written to the pixel PX32. For example, suppose the data voltage DV41 is less than the data voltage DV21. In this case, the greater the difference between the data voltage DV41 and the data voltage DV21, the smaller the data voltage DV41 is provided, so that compensation can be performed so that the desired data voltage DV41 is written to the pixel PX41. This compensation can be performed by the grayscale conversion unit 15 described later, which converts the input grayscale GVi into the output grayscale GVo.

[0075] Figure 5 This is a diagram for explaining a grayscale conversion unit according to an embodiment of the present invention. Figure 6 This is a diagram for explaining a voltage range conversion unit according to an embodiment of the present invention. Figure 7 and Figure 8 This is a diagram for explaining a compensation grayscale calculation unit according to an embodiment of the present invention.

[0076] Reference Figure 5 The grayscale conversion unit 15 a according to an embodiment of the present invention may include a voltage range conversion unit 151 , a memory 152 , a compensation grayscale calculation unit 153 , and an output grayscale calculation unit 154 .

[0077] The voltage domain converter 151 can convert the input grayscale GVi into a converted grayscale VVi in a voltage domain. Figure 6 , shows a graph in which the horizontal axis represents the input grayscale Gvi and the vertical axis represents the converted grayscale VVi. The conversion of the voltage range can be realized independently for each color (red, green, blue). The voltage range conversion unit 151 may include Figure 6 The voltage range converter 151 can use the matching data to convert the input grayscale GVi into a conversion grayscale VVi in the voltage domain.

[0078] Reference Figure 6 The graph of , can be that the higher the input grayscale GVi, the lower the transformed grayscale VVi. In this case, it can be equivalent to Figure 2Assume that the transistor T1 serving as the driving transistor of the pixel PXij is of P-type. If the driving transistor of the pixel PXij is of N-type, the higher the input grayscale GVi is, the higher the conversion grayscale VVi is. Figure 6 The slope of the graph may be based on the gamma value of the gamma curve applied in the display device 10 .

[0079] The memory 152 can output the previous conversion grayscale VVpre corresponding to the previous pixel row. Figure 3 In the case shown in FIG. 1 , the memory 152 can output the previous conversion grayscale VVpre corresponding to the two previous pixel rows. However, in the case where the structure of the pixel unit 14 is as described later, Figure 17 In the case shown, the memory 152 may output a previous converted grayscale VVpre corresponding to a previous pixel row.

[0080] The compensated grayscale calculation unit 153 may calculate the compensated grayscale GC based on the converted grayscale VVi. The compensated grayscale calculation unit 153 may compare the converted grayscale VVi with the previous converted grayscale VVpre to calculate the compensated grayscale GC.

[0081] Reference Figure 7 The compensated grayscale calculation unit 153 may include a lookup table LUT that records compensation values ​​f00, f01, f10, f11, ... corresponding to a portion of the previous converted grayscale VVpre and a portion of the converted grayscale VVi. The lookup table LUT may be provided for each color. For example, the compensated grayscale calculation unit 153 may include a lookup table for red pixels, a lookup table for green pixels, and a lookup table for blue pixels.

[0082] The compensated grayscale calculation unit 153 may interpolate the compensation values ​​f00, f01, f10, f11, ... for a portion of the pixels to calculate first interpolated values. In this case, bi-linear interpolation may be used.

[0083] For example, assume that the lookup table LUT includes compensation values ​​f00, f01, f10, f11, ... corresponding to grayscales 0, 8, 40, 168, and 255 in the previous converted grayscale VVpre and grayscales 0, 8, 40, 168, and 255 in the converted grayscale VVi. In this case, assume that the previous converted grayscale VVpre is grayscale 2 and the converted grayscale VVi is grayscale 208. In this case, p can be 2-0 = 2, and q can be 208-168 = 40. In this case, an exemplary mathematical formula 1 for calculating the desired first interpolated value fpq is as follows.

[0084] [Mathematical formula 1]

[0085]

[0086] Here, LPP may be the maximum value of p, and LPQ may be the maximum value of q. In this example, LPP may be 8-0=8, and LPQ may be 255-168=87.

[0087] Reference Figure 8 Assume that first interpolated values ​​f1, f2, f3, f4, ... are calculated for representative pixels in boundary regions R1, R2, R3, and R4 of pixel unit 14. The first interpolated values ​​f1, f2, f3, f4, ... calculated for the representative pixels can be similarly applied to other pixels belonging to each boundary region R1, R2, R3, and R4. This can be achieved under the premise that the grayscale levels in a sufficiently narrow region are substantially the same. Exemplary Mathematical Formula 2 is as follows.

[0088] [Mathematical formula 2]

[0089] fxy=fpq(R1),if x≤x1and y≤y1[R1]

[0090] =fpq(R2),if x≥x2andy≤y1[R2]

[0091] =fpq(R3),if x≤x1andy≥y2[R3]

[0092] =fpq(R4),if x≥x2andy≥y2[R4]

[0093] In this case, x and y may be the coordinates of the calculation target pixel in the second direction DR2 and the third direction DR3, respectively. x1, x2, y1, and v2 may constitute the boundary coordinates of the boundary regions R1, R2, R3, and R4 and the intermediate regions R5, R6, R7, R8, and R9. fpq(R1) may be the first interpolated value of the representative pixel in boundary region R1, fpq(R2) may be the first interpolated value of the representative pixel in boundary region R2, fpq(R3) may be the first interpolated value of the representative pixel in boundary region R3, and fpq(R4) may be the first interpolated value of the representative pixel in boundary region R4. fxy is the second interpolated value of the calculation target pixel.

[0094] The compensated grayscale calculation unit 153 may interpolate the first interpolated values ​​f1, f2, f3, f4, ... for another portion of the plurality of pixels to calculate a second interpolated value. For example, the compensated grayscale calculation unit 153 may interpolate the first interpolated values ​​f1, f2, f3, f4, ... for the intermediate regions R5, R6, R7, R8, R9 between the boundary regions R1, R2, R3, R4 to calculate a second interpolated value. An exemplary mathematical formula 3 is as follows.

[0095] [Mathematical formula 3]

[0096]

[0097] The compensated grayscale calculation unit 153 may convert the second interpolation value fxy into a grayscale range to provide the compensated grayscale GC.

[0098] The output grayscale calculation unit 154 may add the compensation grayscale GC to the input grayscale GVi to provide an output grayscale GVo.

[0099] The grayscale conversion unit 15a of this embodiment can calculate linear compensation values ​​f00, f01, f10, f11, ... within the voltage range, and can realize the use of linear interpolation for grayscale / position, thereby having the advantage of reducing memory and computational costs.

[0100] Figure 9 and Figure 10 This is a diagram for explaining a maximum brightness gain providing unit according to an embodiment of the present invention.

[0101] Reference Figure 9 The grayscale conversion unit 15b according to an embodiment of the present invention may further include a maximum brightness gain providing unit 155 based on the grayscale conversion unit 15a.

[0102] The maximum brightness gain providing unit 155 can provide a maximum brightness gain Gdbv based on the maximum brightness DBV. The maximum brightness DBV can be the brightness value of the light emitted from each pixel corresponding to the maximum grayscale (for example, 255 grayscale). For example, it can be the brightness value of white light generated by a red pixel forming a dot emitting light corresponding to 255 grayscale, a green pixel emitting light corresponding to 255 grayscale, and a blue pixel emitting light corresponding to 255 grayscale. The unit of the brightness value can be nits. Therefore, the pixel unit 14 can display a partially (spatially) dark or bright image frame, but the maximum brightness of the image frame is limited to the maximum brightness DBV. This maximum brightness DBV can be manually set according to the operation of the user on the display device 10, or can be automatically set by an algorithm associated with an illuminance sensor, etc. Even if the grayscale is the same, if the maximum brightness DBV is different, the data voltage corresponding to the grayscale will become different, and therefore the luminous brightness of the pixel will also become different.

[0103] The maximum brightness gain providing unit 155 may increase the maximum brightness gain Gdbv as the maximum brightness DBV increases. Figure 10 For example, when the maximum brightness DBV is 4 Nits, the maximum brightness gain Gdbv may be set to 0. For example, when the maximum brightness DBV is 1200 Nits, the maximum brightness gain Gdbv may be set to 1.99.

[0104] The compensation grayscale calculation unit 153 may scale the second interpolation value fxy according to the maximum luminance gain Gdbv. For example, the compensation grayscale calculation unit 153 may scale the second interpolation value fxy by multiplying the maximum luminance gain Gdbv. The compensation grayscale calculation unit 153 may convert the scaled second interpolation value fxy into a grayscale range and provide the scaled second interpolation value fxy as the compensation grayscale GC.

[0105] According to this embodiment, a linear compensation value is calculated within the voltage range, thereby achieving a simple multiplication operation of the maximum brightness gain Gdbv, thereby having the advantage of reducing memory and operation costs.

[0106] Figure 11 and Figure 12 This is a diagram for explaining a connection gain providing unit according to an embodiment of the present invention.

[0107] Reference Figure 11 The grayscale conversion unit 15c according to an embodiment of the present invention may further include a connection gain providing unit 156 based on the grayscale conversion unit 15a.

[0108] The connection gain providing unit 156 may provide connection gains Gr, Gg, and Gb for the plurality of first pixels. In one embodiment, the connection gain providing unit 156 may not provide connection gains for the plurality of second pixels. In other embodiments, the connection gain providing unit 156 may provide connection gains for the plurality of second pixels, but the connection gains provided are different from the connection gains Gr, Gg, and Gb for the plurality of first pixels. The connection gain providing unit 156 may receive connection information CNI to confirm whether each pixel belongs to the first pixels PX13 to PX413 or the second pixels PX12 to PX416.

[0109] Reference Figure 12 , as referenced Figure 3As described above, the first pixels PX13 to PX413 can be connected to data lines located in a first direction DR1 based on the first pixels PX13 to PX413. The second pixels PX12 to PX416 can be connected to data lines located in a second direction DR2 based on the second pixels PX12 to PX416. The first direction DR1 and the second direction DR2 can be opposite to each other.

[0110] All pixels in the pixel unit 14 may have the same pixel circuit structure. In this case, the parasitic capacitance of the data line connected to the left side of the pixel circuit (e.g., the first direction DR1) and the data line connected to the right side of the pixel circuit (e.g., the second direction DR2) may be different. Therefore, according to this embodiment, by providing connection gains Gr, Gg, and Gb based on the configuration of the data lines and pixels, compensation for the structure of the pixel unit 14 can be performed. Different connection gains Gr, Gg, and Gb can be provided for each color.

[0111] The compensation grayscale calculation unit 153 may scale the second interpolation value fxy according to the connection gains Gr, Gg, and Gb. For example, the compensation grayscale calculation unit 153 may scale the second interpolation value fxy by multiplying the connection gains Gr, Gg, and Gb. The compensation grayscale calculation unit 153 may convert the scaled second interpolation value fxy into a grayscale range and provide the scaled second interpolation value fxy as the compensation grayscale GC.

[0112] According to this embodiment, by calculating a linear compensation value within the voltage range, a simple multiplication operation of the connection gains Gr, Gg, and Gb can be realized, thereby having the advantage of reducing memory and calculation costs.

[0113] Figure 13 and Figure 14 This is a diagram for explaining a regional gain providing unit according to an embodiment of the present invention.

[0114] Reference Figure 13 The grayscale conversion unit 15d according to an embodiment of the present invention may further include a regional gain providing unit 157 based on the grayscale conversion unit 15a.

[0115] Reference Figure 13 The regional gain providing unit 157 may provide regional gains GAR1 and GAR2 based on the position of each pixel.

[0116] Reference Figure 14 The pixel portion 14 can be divided into a first area AR1, a second area AR2, and a third area AR3. The fourth area AR4 can be considered to be the same as the third area AR3, so repeated description is omitted. Figure 3 The area can also be considered to be the same as the third area AR3, so repeated description is omitted.

[0117] The first area AR1 may include pixels at a first density. The second area AR2 and the third area AR3 may include pixels at a second density higher than the first density. That is, the number of pixels per unit area of ​​the second area AR2 and the third area AR3 may be greater than the number of pixels per unit area of ​​the first area AR1.

[0118] For example, the first area AR1 may include a transmissive region where no pixels exist but light can pass through. In such a transmissive region, various devices such as an image sensor, a camera, a fingerprint sensor, and a proximity sensor may be arranged in a non-overlapping manner on a plane.

[0119] The pixels PX421, PX424, PX425, and PX428 in the second area AR2 can be connected to the same data lines DL21, DL24, DL25, and DL28 as the pixels PX221, PX224, PX225, and PX228 in the first area AR1. Therefore, the number of pixels in the second area AR2 connected to the data lines DL21 to DL28 is less than the number of pixels in the third area AR3 connected to the data lines DL17 to DL20. Consequently, the load on the data lines DL21 to DL28 in the second area AR2 is less than the load on the data lines DL17 to DL20 in the third area AR3. Therefore, a second area gain GAR2 is required for load compensation for the pixels PX421 to PX428 in the second area AR2.

[0120] For similar reasons, the loads on the data lines DL21-DL28 in the first area AR1 are smaller than the loads on the data lines DL17-DL20 in the third area AR3. Therefore, a first area gain GAR1 is required to compensate for the load in the first area AR1. However, the pixel density in the first area AR1 is relatively low, resulting in lower brightness for the same data voltage. Therefore, brightness compensation is also required for the first area gain GAR1. Therefore, the first and second area gains GAR1 and GAR2 can differ from each other. However, the relative magnitudes of the area gains GAR1 and GAR2 can vary depending on the specifications of the display device 10. A separate area gain may not be required for the third area AR3.

[0121] Therefore, the regional gain providing unit 157 may provide a first regional gain GAR1 for each pixel in the first area AR1 and a second regional gain GAR2 for each pixel in the second area AR2. The regional gain providing unit 157 may receive region information ARI in order to determine to which of the first area AR1, the second area AR2, and the third area AR3 a pixel belongs.

[0122] The compensation grayscale calculation unit 153 may scale the second interpolated value fxy based on the regional gains GAR1 and GAR2. For example, the compensation grayscale calculation unit 153 may scale the second interpolated value fxy by multiplying the regional gains GAR1 and GAR2. The compensation grayscale calculation unit 153 may convert the scaled second interpolated value fxy into a grayscale range and provide the scaled second interpolated value fxy as the compensation grayscale GC.

[0123] According to this embodiment, by calculating a linear compensation value within the voltage range, a simple multiplication operation of the regional gains GAR1 and GAR2 can be realized, thereby having the advantage of reducing memory and calculation costs.

[0124] Figure 15 It is a diagram for explaining a grayscale conversion unit according to another embodiment of the present invention.

[0125] Reference Figure 15 The grayscale conversion unit 15e according to one embodiment of the present invention may further include a maximum luminance gain providing unit 155, a connection gain providing unit 156, and a regional gain providing unit 157 based on the grayscale conversion unit 15a. Since the maximum luminance gain providing unit 155, the connection gain providing unit 156, and the regional gain providing unit 157 are the same as those described above, repeated descriptions thereof will be omitted.

[0126] The compensation grayscale calculation unit 153 may scale the second interpolated value fxy based on the maximum luminance gain Gdbv, the connection gains Gr, Gg, Gb, and the regional gains GAR1 and GAR2. For example, the compensation grayscale calculation unit 153 may scale the second interpolated value fxy by multiplying the maximum luminance gain Gdbv, the connection gains Gr, Gg, Gb, and the regional gains GAR1 and GAR2. The compensation grayscale calculation unit 153 may convert the scaled second interpolated value fxy into a grayscale range and provide the scaled second interpolated value fxy as the compensation grayscale GC.

[0127] According to this embodiment, by calculating a linear compensation value within the voltage range, simple multiplication operations of the maximum brightness gain Gdbv, connection gains Gr, Gg, Gb, and regional gains GAR1, GAR2 can be achieved, thereby having the advantage of reducing memory and computational costs.

[0128] Figure 16 It is a diagram for explaining a display device according to another embodiment of the present invention. Figure 17 This is a diagram for explaining a pixel portion according to another embodiment of the present invention.

[0129] Reference Figure 16The display device 10 ′ according to another embodiment of the present invention differs from the display device 10 in that it does not include the data distribution unit 16 . Furthermore, the structure of the pixel unit 14 ′ is different from that of the pixel unit 14 .

[0130] Reference Figure 17 , pixels PX11 to PX48 are respectively connected to data lines located in the first direction DR1 based on the pixels PX11 to PX48. Therefore, the connection information CNI is not required, and the grayscale conversion unit 15 may not include the connection gain providing unit 156. Depending on the embodiment, the grayscale conversion unit 15 may optionally include the maximum luminance gain providing unit 155 and the regional gain providing unit 157.

[0131] As mentioned above, Figure 17 In this case, the memory 152 can output the previous transformed grayscale VVpre corresponding to a previous pixel row.

[0132] The drawings and detailed description of the invention referred to so far are merely illustrative of the present invention and are intended solely for the purpose of illustrating the present invention. They are not intended to limit the meaning or the scope of the invention as described in the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible. Therefore, the true technical scope of the present invention should be determined by the technical principles of the claims.

Claims

1. A display device comprising: A grayscale conversion unit that adds a compensation grayscale to an input grayscale to provide an output grayscale; a data driving unit, providing a data voltage corresponding to the output grayscale; as well as a pixel portion including a plurality of pixels receiving the data voltage, The grayscale conversion unit includes: a voltage range conversion unit that converts the input grayscale into a conversion grayscale within a voltage range; and a compensation grayscale calculation unit that calculates the compensation grayscale based on the conversion grayscale. The grayscale conversion unit further includes a memory for outputting the previous conversion grayscale corresponding to the two previous pixel rows. The compensation grayscale calculation unit includes a lookup table that records compensation values ​​corresponding to a portion of the previous conversion grayscale and a portion of the conversion grayscale. The compensation grayscale calculation unit interpolates the compensation value for a portion of the plurality of pixels to calculate a first interpolation value.

2. The display device according to claim 1, wherein The plurality of pixels are divided into a plurality of first pixels and a plurality of second pixels, The plurality of first pixels are respectively connected to data lines located in a first direction based on the first pixels. The plurality of second pixels are respectively connected to data lines located in a second direction based on the respective second pixels.

3. The display device according to claim 2, further comprising: a data distribution unit connected to the data driving unit via a plurality of data output lines and connected to the plurality of pixels via a plurality of data lines; The number of the plurality of data output lines is less than the number of the plurality of data lines.

4. The display device according to claim 1, wherein The compensated grayscale calculation unit interpolates the first interpolation value for another portion of the pixels to calculate a second interpolation value.

5. The display device according to claim 4, wherein The compensated grayscale calculation unit converts the second interpolation value into a grayscale range and provides the converted value as the compensated grayscale. The display device according to claim 4 , wherein: The grayscale conversion unit further includes a maximum brightness gain providing unit, which provides a maximum brightness gain based on the maximum brightness. The compensation grayscale calculation unit scales the second interpolation value according to the maximum luminance gain, and converts the scaled second interpolation value into a grayscale range to provide the scaled second interpolation value as the compensation grayscale.

7. The display device according to claim 6, wherein: The maximum luminance gain providing unit increases the maximum luminance gain as the maximum luminance increases.

8. The display device according to claim 4, wherein The grayscale conversion unit further includes a connection gain providing unit for providing a connection gain for the first pixel. The compensation grayscale calculation unit scales the second interpolation value according to the connection gain, and converts the scaled second interpolation value into a grayscale range to provide the scaled second interpolation value as the compensation grayscale.

9. The display device according to claim 8, wherein The connection gain providing section does not provide a connection gain for the second pixel.

10. The display device according to claim 4, wherein The grayscale conversion unit further includes a regional gain providing unit configured to provide a regional gain based on the position of the pixel. The compensation grayscale calculation unit scales the second interpolation value according to the regional gain, and converts the scaled second interpolation value into a grayscale range to provide the scaled second interpolation value as the compensation grayscale.

11. The display device according to claim 10, wherein: The pixel portion is divided into a first area, a second area, and a third area. the first region comprising a plurality of pixels at a first density, the second region and the third region include a plurality of pixels at a second density higher than the first density, The pixels in the second area and the pixels in the first area are connected to the same data line, The regional gain providing unit provides a first regional gain to pixels in the first region, and provides a second regional gain to pixels in the second region.

12. A method for driving a display device, comprising: The step of converting the input grayscale into a conversion grayscale of a voltage range; A step of calculating a compensation grayscale based on the transformed grayscale; adding the compensation grayscale to the input grayscale to provide an output grayscale; as well as providing a data voltage corresponding to the output grayscale to a plurality of pixels, Referring to a lookup table, a first interpolation step is calculated for a portion of the pixels among the plurality of pixels by interpolating compensation values, wherein the lookup table records a portion of the previous transformed grayscale corresponding to two previous pixel rows and the compensation values ​​corresponding to a portion of the transformed grayscale.

13. The method for driving a display device according to claim 12, further comprising the following steps: For another portion of the pixels among the plurality of pixels, the first interpolation value is interpolated to calculate a second interpolation value.

14. The method for driving a display device according to claim 13 , further comprising the following steps: The second interpolation is provided as the compensated grayscale.

15. The method for driving a display device according to claim 13, further comprising the following steps: The second interpolation value is scaled according to a maximum luminance gain that increases as the maximum luminance increases, and the scaled second interpolation value is converted into a grayscale range to be provided as the compensated grayscale.

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