KR102307725B1 - Apparatus for generating gray scale voltage and apparatus for driving data for display and display apparatus comprising the same - Google Patents

Abstract

The present invention provides a gray voltage generator capable of changing a specific gray voltage to a desired voltage level, a data driving device for a liquid crystal display device including the same, and a liquid crystal display device, wherein the gray voltage generator according to the present invention includes a plurality of resistors. a voltage generator that divides a plurality of reference gamma voltages and a plurality of gamma adjustment voltages to output a plurality of gray voltages using It may include a node selector.

Description

Apparatus for generating gradation voltage, data driving apparatus for display including same, and display apparatus

The present invention relates to a display device, and more particularly, to a display device capable of changing a specific grayscale voltage to a desired voltage level.

A general liquid crystal display device uses the characteristics of liquid crystal in which light transmittance changes according to a data voltage, and is widely used because it can be driven at a low voltage and consumes little power.

In the liquid crystal display device, an expressible gray range is set by the number of bits of digital image data, and a gray voltage corresponding to the number of bits of digital image data is required to display the gray level.

As the number of bits of digital image data used in a liquid crystal display device increases and a larger number of gray voltages are required, it is difficult to generate all gray voltages from the outside of the data driver and apply them to the data driver. For example, when the number of bits of digital image data is 6 bits, the data driver divides a plurality of reference gamma voltages supplied from the outside by dividing the resistors to generate 64 positive and negative grayscale voltages based on the common voltage. It generates and uses digital image data to convert analog data voltage and supply it to each pixel of the liquid crystal display panel.

The level of the gray voltage is not linearly increased or decreased in order to correct the non-linear light transmittance of the liquid crystal to ensure uniform light transmittance, but is increased or decreased according to a non-linearly set gamma curve.

A typical liquid crystal display device may directly change a gradation voltage corresponding to each of the plurality of reference gamma voltages by changing each of the plurality of reference gamma voltages outside the data driver, but a reference fixed inside the data driver by dividing the resistance A specific grayscale voltage between gamma voltages cannot be changed outside the data driver.

Therefore, since the general liquid crystal display device relies on each adjustment of a plurality of reference gamma voltages during gamma tuning for changing the gamma curve or improving image quality such as color difference, it is possible to change a specific gray level voltage to a desired voltage level. However, there is a problem in that it is impossible to generate a grayscale voltage that matches the set gamma curve.

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a gray voltage generating device capable of changing a specific gray voltage to a desired voltage level, a data driving device for a display including the same, and a display device.

According to an aspect of the present invention, there is provided an apparatus for generating a grayscale voltage by using a plurality of resistors to divide a plurality of reference gamma voltages and a plurality of gamma adjustment voltages to output a plurality of grayscale voltages; A node selector may include a node selector that selects a node to which a plurality of gamma adjustment voltages are respectively supplied from among the nodes between the plurality of resistors.

According to the means for solving the above problem, according to the present invention, a gray level voltage matching a desired gamma curve can be generated by directly externally changing the voltage level of a specific desired gray level voltage among a plurality of gray level voltages, and through this, the afterimage of the display device is generated. and color difference can be improved.

In addition to the effects of the present invention mentioned above, other features and advantages of the present invention will be described below or will be clearly understood by those of ordinary skill in the art from such description and description.

1 is a block diagram schematically illustrating an apparatus for generating a grayscale voltage according to an exemplary embodiment of the present invention.
FIG. 2 is a circuit diagram illustrating the first voltage generator shown in FIG. 1 .
FIG. 3 is a circuit diagram for explaining the second voltage generator shown in FIG. 1 .
FIG. 4 is a view for explaining a third voltage generator and a node selector shown in FIG. 1 .
FIG. 5 is a diagram for explaining the node selector shown in FIGS. 1 and 4 .
6 is a diagram schematically illustrating a display device according to the present invention.
7 is a block diagram schematically illustrating a data driver illustrated in FIG. 6 .

The meaning of the terms described herein should be understood as follows.

The singular expression is to be understood as including the plural expression unless the context clearly defines otherwise, and the terms "first", "second", etc. are used to distinguish one element from another, The scope of rights should not be limited by these terms. It should be understood that terms such as “comprise” or “have” do not preclude the possibility of addition or existence of one or more other features or numbers, steps, operations, components, parts, or combinations thereof. The term “at least one” should be understood to include all possible combinations from one or more related items. For example, the meaning of "at least one of the first, second, and third items" means 2 of the first, second, and third items as well as each of the first, second, or third items. It means a combination of all items that can be presented from more than one. The term "on" is meant to include not only cases in which a certain component is formed directly on top of another component, but also a case in which a third component is interposed between these components.

Hereinafter, a preferred example of a driving device for a liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

1 is a block diagram schematically illustrating an apparatus for generating a grayscale voltage according to an exemplary embodiment of the present invention.

Referring to FIG. 1 , an apparatus for generating a gray voltage according to an embodiment of the present invention generates a plurality of gray voltages GV0 to GV63, and includes a maximum gray voltage GV63 and an intermediate gray level among the plurality of gray voltages GV0 to GV63. The voltage level of each of the voltage GV32 and the minimum gradation voltage GV0 is directly changed externally, and the desired specific gradation voltage between the maximum gradation voltage GV63 and the half gradation voltage GV32 and the minimum gradation voltage GV0 is obtained. The voltage level can be changed directly externally. To this end, the gray voltage generator includes first to third voltage generators 110 , 120 , and 130 , a node selection signal generator 140 , and a node selector 150 .

The first voltage generator 110 generates a plurality of reference gamma voltages RGV1 , RGV2 , and RGV3 having different voltage levels, and converts the generated reference gamma voltages RGV1 , RGV2 , and RGV3 to a third voltage. output to the generator 130 . For example, the first voltage generator 110 may generate a voltage level corresponding to each of the maximum gray voltage GV63, the intermediate gray voltage GV32, and the minimum gray voltage GV0 among the plurality of gray voltages GV0 to GV63. The first to third reference gamma voltages RGV1 , RGV2 , and RGV3 may be generated.

The first voltage generator 110 divides first and second driving voltages Vdd and Vss having different voltage levels to generate first to third reference gamma voltages RGV1, RGV2, and RGV3. can As shown in FIG. 2 , the first voltage generator 110 according to an example includes a first variable resistor VR1 to which a first driving voltage Vdd is applied, and a first variable resistor VR1 to which a second driving voltage Vss is applied. It may include a second variable resistor VR2, and first and second voltage dividing resistors DR1 and DR2 connected in series between the first variable resistor VR1 and the second variable resistor VR2. The first voltage generator 110 according to this example includes first to third references generated at a node between the series-connected variable resistors VR1 and VR2 and the voltage dividing resistors DR1 and DR2 through resistance division between them. Each of the gamma voltages RGV1, RGV2, and RGV3 is output. Here, each of the first and second voltage-dividing resistors DR1 and DR2 illustrated in FIG. 2 may be replaced with a voltage-dividing resistor series in which a plurality of voltage-dividing resistors are connected in series. As described above, the voltage level of each of the first to third reference gamma voltages RGV1 , RGV2 , and RGV3 in the first voltage generator 110 is set in advance by the first variable resistor VR1 and/or the second variable resistor (VR2) can be changed according to each resistance value.

Referring back to FIG. 1 , the second voltage generator 120 includes a plurality of reference gamma voltages, that is, a plurality of gamma adjustment voltages having voltage levels between the first to third reference gamma voltages RGV1 , RGV2 , and RGV3 . (GAV1 to GAV4) is generated, and a plurality of generated gamma adjustment voltages GAV1 to GAV4 are output to the node selector 150 . That is, the second voltage generator 120 includes first and second gamma adjustment voltages GAV1 and GAV2 having different voltage levels between the first reference gamma voltage RGV1 and the second reference gamma voltage RGV2; and third and fourth gamma adjustment voltages GAV3 and GAV4 having different voltage levels between the second reference gamma voltage RGV2 and the third reference gamma voltage RGV3, respectively.

As an example, the second voltage generator 120 includes a maximum grayscale voltage GV63, a middle grayscale voltage GV32, and a minimum grayscale voltage GV0 to GV63 output from the third voltage generator 130 . Each of the first to fourth gamma adjustment voltages GAV1 to GAV4 is generated so that the voltage levels of the gray voltages GV1 to GV31 and GV33 to GV62 between the gray voltage GV0 match the voltage level of the desired gamma curve. can do. As another example, the second voltage generator 120 may include the remaining grayscale voltages except for the maximum grayscale voltage GV63, the intermediate grayscale voltage GV32, and the minimum grayscale voltage GV0 output from the third voltage generator 130 . Each of the first to fourth gamma adjustment voltages GAV1 to GAV4 may be generated to change a desired specific grayscale voltage from among the GV1 to GV31 and GV33 to GV62 to a desired voltage level. As a result, each of the first to fourth gamma adjustment voltages GAV1 to GAV4 may be a specific grayscale voltage selected during external gamma tuning for image quality improvement such as improvement of an afterimage and/or color difference of a display device.

The second voltage generator 120 may divide the first and second driving voltages Vdd and Vss to generate first to fourth gamma adjustment voltages GAV1 to GAV4. As shown in FIG. 3 , the second voltage generator 120 according to an example may include first to fourth voltage division circuits 121 to 124 .

Each of the first to fourth voltage division circuits 121 to 124 includes a third variable resistor VR3 to which the first driving voltage Vdd is applied, and a fourth variable resistor VR4 to which the second driving voltage Vss is applied. ), and a contact CP connected to the third variable resistor VR3 and the fourth variable resistor VR4. Each of the first to fourth variable resistance columns 121 to 124 is contacted according to voltage distribution of the first and second driving voltages Vdd according to the resistance values of the third and fourth variable resistors VR3 and VR4. The gamma adjustment voltage generated at (CP) is output. Here, the resistance values of the third and fourth variable resistors VR3 and VR4 may be set to different values for each of the first to fourth voltage division circuits 121 to 124 . That is, each of the third and fourth variable resistors VR3 and VR4 for each of the voltage division circuits 121 to 124 applies the first to fourth gamma adjustment voltages GAV1 to GAV4 corresponding to the gray scale voltage selected during the gamma tuning. It can have a resistance value to generate.

As described above, each of the first to fourth voltage division circuits 121 to 124 includes variable resistors VR3 and VR4, so that the present invention provides a gamma adjustment voltage by changing the resistance values of the variable resistors VR3 and VR4. can be set to a desired voltage level, and through this, a desired specific grayscale voltage using the gamma adjustment voltage can be changed to a desired voltage level.

Referring back to FIG. 1 , the third voltage generator 130 divides a plurality of reference gamma voltages RGV1 , RGV2 , and RGV3 and a plurality of gamma adjustment voltages GAV1 to GAV4 through a plurality of resistors to obtain a plurality of voltages. of the grayscale voltages GV0 to GV63 and output the plurality of generated grayscale voltages GV0 to GV63. Here, the plurality of grayscale voltages GV0 to GV63 are supplied to a digital-analog converter (not shown) of the data driving integrated circuit. The data driving integrated circuit is connected to a data line of a display panel in the display device, and serves to convert input digital image data into an analog data voltage and supply it to the data line. The digital-to-analog converter selects one grayscale voltage corresponding to digital image data from among the plurality of grayscale voltages GV0 to GV63 and outputs the selected grayscale voltage as a data voltage.

As shown in FIG. 4 , the third voltage generator 130 according to an example includes a resistance column 131 for grayscale voltages formed of a plurality of resistors R connected in series. Here, each of the plurality of resistors R is electrically connected in series, and may have different resistance values or the same resistance value.

The resistance column 131 for the gray voltage includes first to third reference nodes RN1, RN2, and RN3 to which a plurality of reference gamma voltages, that is, the first to third reference gamma voltages RGV1, RGV2, and RGV3 are respectively supplied. , and first to fourth node groups NG1, NG2, NG3, and NG4 provided between the first to third reference nodes RN1, RN2, and RN3.

The first reference node RN1 is provided at the upper end of the resistance column 131 for the grayscale voltage. At the first reference node RN1 , the first reference gamma voltage RGV1 supplied from the first voltage generator 110 is output as the maximum grayscale voltage GV63 .

The second reference node RN2 is provided in the middle of the resistance column 131 for the grayscale voltage. At the second reference node RN2 , the second reference gamma voltage RGV2 supplied from the first voltage generator 110 is output as the half-gray voltage GV32 .

The third reference node RN3 is provided at the lower end of the resistance column 131 for the gray voltage. At the third reference node RN3 , the third reference gamma voltage RGV3 supplied from the first voltage generator 110 is output as the minimum grayscale voltage GV0 .

The first and second node groups NG1 and NG2 are provided between the first and second reference nodes RN1 and RN2.

The first node group NG1 includes a plurality of first voltage adjustment nodes 1N1 to 1N16 provided between a plurality of resistors R connected in series to the first reference node RN1. For example, the first node group NG1 may have 16 first voltage adjustment nodes 1N1 to 1N16. In this case, the first node group NG1 includes 16 first voltage adjustment nodes 1N1. ~ 1N16), 16 gray voltages (GV48 ~ GV62) are output.

The second node group NG2 includes a plurality of second voltage adjustment nodes 2N1 to provided between a plurality of resistors R connected in series between the first node group NG1 and the second reference node RN2. 2N15). For example, the second node group NG2 may have 15 second voltage regulation nodes 2N1 to 2N15. In this case, the second node group NG2 includes 15 second voltage regulation nodes 2N1. ~ 2N15), 15 grayscale voltages (GV33 ~ GV47) are output. Meanwhile, the first voltage adjustment node 1N16 of the first node group NG1 closest to the second node group NG2 may be shared with the second node group NG2, and in this case, the The two-node group NG2 has 16 second voltage regulation nodes 1N16, 2N1 to 2N15, and thus 16 gray-scale voltages GV33 to GV48 through the 16 second voltage regulation nodes 1N16, 2N1 to 2N15. ) can be printed.

The third and fourth node groups NG3 and NG4 are provided between the second and third reference nodes RN2 and RN3.

The third node group NG3 includes a plurality of third voltage adjustment nodes 3N1 to 3N15 provided between a plurality of resistors R connected in series to the second reference node RN2. For example, the third node group NG3 may have 15 third voltage regulation nodes 3N1 to 3N15. In this case, the third node group NG3 includes 15 third voltage regulation nodes 3N1. ~ 3N15), 15 grayscale voltages (GV17 ~ GV31) are output.

The fourth node group NG4 includes a plurality of fourth voltage adjustment nodes 4N1 to provided between a plurality of resistors R connected in series between the third node group NG3 and the third reference node RN3. 4N16). For example, the fourth node group NG4 may have 16 fourth voltage regulation nodes 4N1 to 4N16. In this case, the fourth node group NG4 includes 16 fourth voltage regulation nodes 4N1. ~ 4N16), 16 grayscale voltages (GV1 ~ GV16) are output.

Meanwhile, the fourth voltage adjustment node 4N1 of the fourth node group NG4 closest to the third node group NG3 may be shared by the third node group NG3. In this case, the first The three-node group NG3 has 16 third voltage regulation nodes 3N1 to 3N15 and 4N1, and thus 16 grayscale voltages GV16 to GV31 through the 16 third voltage regulation nodes 3N1 to 3N15 and 4N1. ) can be printed.

Referring back to FIG. 1 , the node selection signal generator 140 generates a plurality of node selection group signals NGS1 to NGS4 including a plurality of node selection signals, and the generated plurality of node selection group signals NGS1 to NGS1 . NGS4) is supplied to the node selector 150 . The node selection signal generator 140 according to an example generates first to fourth node selection group signals NGS1 to NGS4 having first to fourth node selection signals having a preset high logic state or a low logic state. The output may be made of any one of a resistor (not shown), a dip switch (not shown), and a resistor circuit (not shown) having a voltage division resistance column. Here, the node selection signal generator 140 and the first and second voltage generators 110 and 120 may be provided on the same printed circuit board (not shown). The printed circuit board may be a data printed circuit board or a control board of a display device connected to a data driving integrated circuit.

In response to each of the plurality of node selection group signals NGS1 to NGS4, the node selector 150 selects the plurality of gamma adjustment voltages ( Each of GAV1 to GAV4 selects a voltage adjustment node to be supplied, and supplies the gamma adjustment voltages GAV1 to GAV4 corresponding to the selected voltage adjustment node. That is, the node selector 150 performs external gamma tuning for image quality improvement such as improvement of an afterimage and/or color difference of a display device through a change of a specific grayscale voltage. The gamma adjustment voltages GAV1 to GAV4 are directly supplied to the voltage adjustment node corresponding to the specific gray level voltage among the voltage adjustment nodes, thereby changing the voltage level of the specific gray level voltage.

As shown in FIGS. 1 and 4 , the node selector 150 according to an example includes a plurality of selectors 151 to 154 , and more specifically, the first to fourth selectors 151 to 154) may be included.

Each of the first to fourth selectors 151 to 154 selects any one of the plurality of voltage adjustment nodes NA included in the corresponding node group NG for the node selection group signal NGS. ), and a corresponding gamma adjustment voltage GAV is supplied to the selected voltage adjustment node NA. That is, the first selector 151 supplies the first gamma adjustment voltage GAV1 to any one of the plurality of first voltage adjustment nodes 1N1 to 1N16 included in the first node group NG1 . The second selector 152 supplies a second gamma adjustment voltage GAV2 to any one of a plurality of second voltage adjustment nodes 2N1 to 2N15 included in the second node group NG2. In addition, the third selector 153 supplies the third gamma adjustment voltage GAV3 to any one of the plurality of third voltage adjustment nodes 3N1 to 3N15 included in the third node group NG3. The fourth selector 154 supplies the fourth gamma adjustment voltage GAV4 to any one of the plurality of fourth voltage adjustment nodes 4N1 to 4N16 included in the fourth node group NG4.

As shown in FIG. 5 , the first selector 151 according to an example includes one input terminal IT, a plurality of output terminals OT1 to OT16, a selection signal inversion unit 150a, and a switching signal generation. It includes a unit 150b, and a plurality of switching elements SD1 to SD16.

The input terminal IT is connected to the first voltage divider circuit 121 of the second voltage generator 120 . The first gamma adjustment voltage GAV1 generated by the first voltage divider circuit 121 is supplied to the input terminal IT.

The plurality of output terminals OT1 to OT16 are one-to-one connected to the plurality of first voltage adjustment nodes 1N1 to 1N16 included in the first node group NG1. The first gamma adjustment voltage GAV1 supplied to the input terminal IT is output to any one of the plurality of output terminals OT1 to OT16.

The selection signal inverting unit 150a is inverted with each of the first to fourth node selection signals NS1 to NS4 included in the first node selection group signal NGS1 supplied from the node selection signal generating unit 140 . First to fourth inverted node selection signals NS1' to NS4' are generated, and first to fourth node selection signals NS1 to NS4 and first to fourth inverted node selection signals NS1' to NS4' are generated. output together. The selection signal inverting unit 150a according to an example may include first to fourth inverters IN1 to IN4 that invert the logic states of the first to fourth node selection signals NS1 to NS4, respectively.

The switching signal generator 150b is configured to generate a plurality of switching signals SS1 to SS16 based on the first to fourth node selection signals NS1 to NS4 and the first to fourth inverted node selection signals NS1′ to NS4′. ) is created. That is, the switching signal generator 150b receives the first to fourth node selection signals NS1 to NS4 and the first to fourth inverted node selection signals NS1' to NS4' supplied to correspond to the 4-bit truth table. The first to sixteenth switching signals SS1 to SS16 may be generated by a 4-bit logic combination. The switching signal generator 150b according to an example includes first to sixteenth logic gates AG1 to AG16.

Each of the first to sixteenth logic gates AG1 to AG16 is in a 4-bit truth table among the first to fourth node selection signals NS1 to NS4 and the first to fourth inverted node selection signals NS1' to NS4'. The switching signals SS1 to SS16 are generated by performing an OR operation on the correspondingly supplied node selection signals. For example, the first logic gate AG1 generates a first switching signal SS1 by performing an AND operation on the first to fourth inverted node selection signals NS1' to NS4', and the second logic gate (AG2) generates a second switching signal (SS2) by performing an OR operation on the first node selection signal (NS1) and the second to fourth inverted node selection signals (NS2', NS3', NS4'), 15 logic gate AG15 generates a fifteenth switching signal SS15 by performing an OR operation on the first inverted node selection signal NS1' and the second to fourth node selection signals NS2, NS3, and NS4, The sixteenth logic gate AG16 may perform an AND operation on the first to fourth node selection signals NS1 , NS2 , NS3 , and NS4 to generate the sixteenth switching signal SS16 .

The selection signal inverting unit 150a and the switching signal generating unit 150b are based on the first to fourth node selection signals NS1, NS2, NS3, and NS4 included in the first node selection group signal NGS1. It may be a 4×16 decoder generating the first to sixteenth switching signals SS1 to SS16.

Each of the plurality of switching elements SD1 to SD16 is commonly connected to the input terminal IT, and is connected to a corresponding output terminal among the plurality of output terminals OT1 to OT16. Each of the plurality of switching elements SD1 to SD16 is turned on according to a corresponding switching signal SS1 to SS16 and corresponds to the first gamma adjustment voltage GAV1 supplied to the input terminal IT. output to the output terminal. Accordingly, the first gamma adjustment voltage GAV1 is switched on through any one of the plurality of switching elements SD1 to SD16 turned on according to the first to sixteenth switching signals SS1 to SS16. It is output to the output terminal connected to the device.

Each of the second to fourth selectors 152 , 153 , and 154 according to an example includes the first to fourth node selection signals NS1 , NS2 , and NS3 included in the corresponding node selection group signals NGS2 , NGS3 , and NGS4 . , NS4) is the same as the above-described first selector 151 except for generating a plurality of switching signals and outputting a corresponding gamma adjustment voltage according to the plurality of switching signals. to be omitted.

As described above, in the gray voltage generating apparatus according to the present invention, the maximum gray voltage GV63 having a voltage level fixed by the first to third reference gamma voltages RGV1, RGV2, and RGV3 among the plurality of gray voltages GV0 to GV63. ) and the voltage level of a specific desired grayscale voltage between the intermediate grayscale voltage GV32 and the minimum grayscale voltage GV0 is directly changed from the outside to generate a grayscale voltage that matches the desired gamma curve. It can improve afterimage and color difference. In particular, the gray voltage generating apparatus according to the present invention may obtain a plurality of gray voltages GV0 to GV63 by fixing voltage levels of the maximum gray voltage GV63, the intermediate gray voltage GV32, and the minimum gray voltage GV0, respectively. It can be easily matched to the gamma curve.

Meanwhile, the plurality of gray voltages GV0 to GV63 output from the gray voltage generator according to the present invention described above may be used as gray voltages of the organic light emitting display device.

Furthermore, the plurality of gray voltages GV0 to GV63 output from the gray voltage generator according to the present invention described above may be used as a plurality of positive gray voltages for the liquid crystal display device. Additionally, the gray voltage generating apparatus according to the present invention described above may additionally output a plurality of gray voltages used as a plurality of negative gray voltages for the liquid crystal display device. To this end, the first voltage generator 110 additionally generates fourth to sixth reference gamma voltages symmetrical to the first to third reference gamma voltages based on the common electrode voltage, and the third voltage generator (130). The second voltage generator 120 additionally generates fifth to eighth gamma adjustment voltages that are symmetrical with the first to fourth gamma adjustment voltages based on the common electrode voltage, and transmits the fifth to eighth gamma adjustment voltages to the third voltage generator 130 . supply The resistance column 131 for gray voltage of the third voltage generator 130 is provided between fourth to sixth reference nodes to which fourth to sixth reference gamma voltages are respectively supplied, and the fourth to sixth reference nodes. It further includes fifth to eighth node groups. The node selection signal generator 140 additionally generates fifth to eighth node selection group signals. The node selector 150 selects one voltage adjustment node corresponding to the fifth to eighth node selection group signal from among the voltage adjustment nodes for each fifth to eighth node group, and selects a fifth voltage adjustment node corresponding to the selected voltage adjustment node. to an eighth gamma adjustment voltage is supplied.

6 is a diagram schematically illustrating a display device according to the present invention.

Referring to FIG. 6 , the display device according to the present invention includes a display panel 200 , a timing controller 300 , a gate driver 400 , first and second voltage generators 110 and 120 , and a node selection signal generator. 140 , and a data driver 500 .

The display panel 200 includes a plurality of pixels P formed in each pixel area defined by intersections of a plurality of gate lines GL and a plurality of data lines DL.

Each of the plurality of pixels P includes a thin film transistor T connected to a gate line GL and a data line DL, a liquid crystal capacitor C1 connected to the thin film transistor T, and a storage capacitor C2. includes

The liquid crystal capacitor C1 includes a pixel electrode connected to the thin film transistor T and a common electrode parallel to the pixel electrode with a liquid crystal layer interposed therebetween. The liquid crystal capacitor C1 drives the liquid crystal molecules of the liquid crystal layer according to an electric field formed by the data voltage Vdata supplied to the pixel electrode and the common electrode voltage Vcom supplied to the common electrode.

The storage capacitor C2 stores the data voltage Vdata supplied through the thin film transistor T, and provides the charged data voltage Vdata to the liquid crystal capacitor C1 when the thin film transistor T is turned off. The voltage charged in the capacitor C1 is maintained until the data voltage Vdata of the next frame is supplied. Here, the storage capacitor C1 may be formed by overlapping the pixel electrode and the common electrode, or may be formed by overlapping the pixel electrode and the previous gate line.

The timing controller 300 receives a timing synchronization signal TSS and digital image data Idata from an external driving system (eg, a graphic card). The timing controller 300 aligns the input digital image data Idata based on the timing synchronization signal TSS to suit the pixel arrangement structure of the display panel 200 , and arranges the aligned pixel data R, G, and B). is provided to the data driver 500 . In addition, the timing controller 300 controls the gate control signal GCS for controlling the driving timing of the gate driver 400 and data control for controlling the driving timing of the data driver 500 based on the timing synchronization signal TSS. Generate a signal DCS. Here, the gate control signal GCS may include a gate start pulse and a plurality of gate shift clocks. In addition, the data control signal DCS may include a source start pulse, a source sampling clock, a source output enable, and a polarity control signal.

The gate driver 400 generates a gate pulse GP in response to a gate control signal GCS supplied from the timing controller 300 , that is, a gate start pulse and a plurality of gate shift clocks, and generates the gate pulse GP. ) is sequentially supplied to the plurality of gate lines GL. The gate driver 400 according to an example may be mounted on a gate flexible circuit film (not shown) and connected to the plurality of gate lines GL through the gate flexible circuit film. The gate driver 400 according to another example is not mounted on the gate flexible circuit film, but is mounted on the display panel 200 in the form of a chip by a chip on glass method, or is mounted on a gate in panel (Gate In Panel). ) method may be directly formed on the display panel 200 at the same time as the formation process of the thin film transistor.

The first voltage generator 110 generates a plurality of reference gamma voltages RGV and provides it to the data driver 500 , which is the same as described above, and thus a redundant description thereof will be omitted.

The second voltage generator 120 generates a plurality of gamma adjustment voltages GAV and provides them to the data driver 500 , which is the same as described above, and thus a redundant description thereof will be omitted.

The node selection signal generator 140 generates a plurality of node selection group signals NGS including a plurality of node selection signals and provides them to the data driver 500 , which is the same as described above, and thus overlaps therewith. A description will be omitted.

The timing controller 300 , the first and second voltage generators 110 and 120 , and the node selection signal generator 140 may be provided on the same printed circuit board 310 . The printed circuit board 310 may be a data printed circuit board connected to the data driver 500 or a control board.

The data driver 500 supplies the data voltage Vdata to the data line DL of the display panel 200 . That is, the data driver 500 includes a data control signal DCS and pixel data R, G, and B from the timing controller 300 , a plurality of reference gamma voltages RGV from the first voltage generator 110 , A plurality of gamma adjustment voltages GAV are supplied from the second voltage generator 120 , and a plurality of node selection group signals NGS are supplied from the node selection signal generator 140 , respectively. Accordingly, the data driver 500 generates a plurality of grayscale voltages according to the plurality of reference gamma voltages RGV, the plurality of gamma adjustment voltages GAV, and the plurality of node selection group signals NGS, while generating the data control signal ( DCS), the pixel data R, G, and B are sampled, and a grayscale voltage corresponding to the sampled sampled data is selected from among a plurality of grayscale voltages and output as the data voltage Vdata. As such, the data driver 500 may be a data driver integrated circuit connected to the data line DL.

7 is a block diagram schematically illustrating a data driver illustrated in FIG. 6 .

6 and 7, the data driving unit 500 according to the present invention includes a signal control unit 510, a grayscale voltage generation unit 530, a digital processing unit 550, an analog processing unit 570, and an output buffer unit ( 590).

The signal controller 510 receives the data control signal DCS and the pixel data R, G, and B supplied from the timing controller 300 , and the received data control signal DCS and the pixel data R, G , B) is output.

The gray voltage generator 530 includes a plurality of reference gamma voltages RGV supplied from the first voltage generator 110 and a plurality of gamma adjustment voltages GAV supplied from the second voltage generator 120 . , and a plurality of positive grayscale voltages PGV and a plurality of negative grayscale voltages NGV are generated and output based on the plurality of node selection group signals NGS supplied from the node selection signal generator 140 . . To this end, the gray voltage generator 530 includes a gray voltage output unit 532 and a node selector 534 .

The gray voltage output unit 532 includes a plurality of reference gamma voltages (RGV) through a resistance string for gray voltages including a plurality of resistors connected in series to include a plurality of node groups having a plurality of reference nodes and a plurality of voltage adjustment nodes. ) and the plurality of gamma adjustment voltages GAV, symmetric with respect to the common electrode voltage, and 63 positive grayscale voltages PGV and 63 corresponding to the total number of grayscales of the pixel data R, G, and B. Negative negative grayscale voltages NGV are generated. Since the gray-scale voltage output unit 532 is the same as the third voltage generator shown in FIGS. 1 and 4 , a redundant description thereof will be omitted. Accordingly, the gray voltage output unit 532 operates in the same manner as the above-described third voltage generator 130 to generate 63 positive gray voltages PGV and, although not shown, the positive gray voltage PGV. ), 63 negative grayscale voltages NGV symmetrical with 63 positive grayscale voltages PGV are generated based on the common electrode voltage.

The node selector 534 selects a voltage adjustment node to which the gamma adjustment voltage GAV is to be supplied from among a plurality of voltage adjustment nodes for each node group in response to each of the plurality of node selection group signals NGS, and selects the selected voltage adjustment node A gamma adjustment voltage (GAV) is supplied to the

The digital processing unit 550 sequentially generates sampling signals according to the source start pulse SSP and the source shift signal SSC supplied from the signal control unit 510 , and the pixel data R supplied from the signal control unit 510 . , G, and B) are sequentially sampled according to the sampling signal, and then the sampled data Sdata sampled according to the source output enable signal SOE is simultaneously output to the analog processing unit 570 .

The analog processing unit 570 uses the plurality of positive grayscale voltages PGV and the plurality of negative grayscale voltages NGV supplied from the grayscale voltage generator 530 to generate sampling data ( Sdata) into positive and negative data voltages Vdata, and then selects and outputs positive or negative data voltages Vdata according to the polarity control signal POL supplied from the signal controller 510 output to the buffer unit 590 .

The output buffer unit 590 buffers the data voltage Vdata supplied from the analog processing unit 570 and outputs it to the corresponding data line DL.

As described above, the display device according to the present invention can generate a gradation voltage that matches a desired gamma curve by including the gradation voltage generator according to the present invention, thereby reducing the afterimage and color difference displayed on the display panel 200 . can be improved

Meanwhile, in the above description, the display panel 200 has been described as a liquid crystal display panel including a liquid crystal layer, but the present invention is not limited thereto, and the display panel 200 may be an organic light emitting display panel. In this case, the gray voltage generator 530 of the above-described data driver 500 generates a plurality of gray voltages GV0 to GV63 in the same manner as the third voltage generator shown in FIGS. 1 and 4 .

Also, in the above description, it has been described that the gray voltage generator and the gray voltage generator output 64 gray voltages, but the present invention is not limited thereto. A gradation voltage corresponding to the number of gradations may be generated. In addition, in the above description, it has been described that each node group consists of 16 voltage control nodes and an externally changeable gamma control voltage is directly supplied to any one of the 16 voltage control nodes through the node selector, but the present invention is not limited thereto. Each node group is composed of 8i (where i is a natural number greater than or equal to 2) voltage adjustment nodes according to the total number of grayscales of the digital image data, and the gamma adjustment voltage is selected from any of the 8i voltage adjustment nodes through the above-described node selector. can be supplied directly to one.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes are possible without departing from the technical matters of the present invention. It will be clear to those who have the knowledge of Therefore, the scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

110: first voltage generator 120: second voltage generator
121, 122, 123, 124: voltage divider circuit 130: third voltage generator
131: resistance column for gradation voltage 140: node selection signal generator
150, 534: node selection unit 150a: selection signal inverting unit
150b: switching signal generator 151, 152, 153, 154: selector
200: display panel 300: timing control unit
400: gate driver 500: data driver
530: gray voltage generator 532: gray voltage output unit
550: digital processing unit 570: analog processing unit

Claims (13)

a first voltage generator outputting a plurality of reference gamma voltages having different voltage levels;
a second voltage generator configured to generate a plurality of gamma adjustment voltages having different voltage levels among the plurality of reference gamma voltages;
a third voltage generator for voltage-dividing the plurality of reference gamma voltages and the plurality of gamma adjustment voltages through a plurality of resistors to output a plurality of grayscale voltages;
a node selection signal generator outputting a plurality of node selection group signals; and
a node selector configured to select a node to which the plurality of gamma adjustment voltages are respectively supplied from among the nodes between the plurality of resistors in response to each of the plurality of node selection group signals;
The second voltage generator includes a plurality of voltage division circuits for generating each of the plurality of gamma adjustment voltages, and each of the plurality of voltage division circuits includes a plurality of variable resistors. The method of claim 1,
The first voltage generator generates the plurality of reference gamma voltages having voltage levels corresponding to the maximum grayscale voltage, the intermediate grayscale voltage, and the minimum grayscale voltage from among the plurality of grayscale voltages, and supplies the generated reference gamma voltages to the third voltage generator; Gradation voltage generator. 3. The method of claim 2,
and each of the plurality of voltage division circuits divides first and second driving voltages having different voltage levels through a plurality of series-connected variable resistors to generate a corresponding gamma adjustment voltage. 4. The method of claim 3,
The third voltage generator includes a resistor string for grayscale voltage to which the plurality of resistors are connected in series,
The resistance heat for the gradation voltage is,
a plurality of reference nodes to which the plurality of reference gamma voltages are respectively supplied; and
a plurality of node groups having a plurality of voltage regulation nodes provided between the plurality of reference nodes;
and a gamma adjustment voltage is supplied from the node selector to any one of the plurality of voltage adjustment nodes for each node group. 5. The method of claim 4,
The node selection unit includes a plurality of selection units,
Each of the plurality of selection units selects any one voltage adjustment node from among a plurality of voltage adjustment nodes included in a corresponding node group according to the node selection group signal, and supplies the gamma adjustment voltage to the selected voltage adjustment node, Gradation voltage generator. 6. The method of claim 5,
Each of the plurality of selection units,
one input terminal to which a gamma adjustment voltage is supplied from the second voltage generator;
a plurality of output terminals connected one-to-one to the plurality of voltage regulation nodes;
a switching signal generator configured to generate a plurality of switching signals based on a corresponding node selection group signal; and
a plurality of switching elements commonly connected to the input terminal and individually connected to the plurality of output terminals, each of which is switched by the plurality of switching signals to output a gamma adjustment voltage supplied to the input terminal to an output terminal; , a gradation voltage generator. a digital processing unit for sampling and outputting input digital image data;
a gradation voltage generator generating a plurality of gradation voltages;
an analog processing unit that converts the sampling data into data voltages using the plurality of grayscale voltages; and
an output buffer unit for outputting the data voltage;
The gradation voltage generator,
It receives a plurality of reference gamma voltages having different voltage levels and a plurality of gamma adjustment voltages having voltage levels between the plurality of reference gamma voltages, and receives a plurality of reference gamma voltages and a plurality of gamma adjustment voltages through a plurality of resistors a gradation voltage output unit that divides the voltage and outputs the plurality of gradation voltages; and
and a node selector configured to select a node to which the plurality of gamma adjustment voltages are respectively supplied from among the nodes between the plurality of resistors in response to each of a plurality of node selection group signals. 8. The method of claim 7,
The gray voltage output unit includes a resistance string for gray voltage in which the plurality of resistors are connected in series,
The resistance heat for the gradation voltage is,
a plurality of reference nodes to which the plurality of reference gamma voltages are respectively supplied; and
a plurality of node groups having a plurality of voltage regulation nodes provided between the plurality of reference nodes;
and a gamma adjustment voltage is supplied from the node selector to any one of the plurality of voltage adjustment nodes for each node group. 9. The method of claim 8,
The node selection unit includes a plurality of selection units,
Each of the plurality of selection units selects any one voltage adjustment node from among a plurality of voltage adjustment nodes included in a corresponding node group according to the node selection group signal, and supplies the gamma adjustment voltage to the selected voltage adjustment node, Data driver for display. 10. The method of claim 9,
Each of the plurality of selection units,
one input terminal to which a corresponding gamma adjustment voltage is supplied;
a plurality of output terminals connected one-to-one to the plurality of voltage regulation nodes;
a switching signal generator configured to generate a plurality of switching signals based on a corresponding node selection group signal; and
a plurality of switching elements commonly connected to the input terminal and individually connected to the plurality of output terminals, each of which is switched by the plurality of switching signals to output a gamma adjustment voltage supplied to the input terminal to an output terminal; A data driving device for a display. display panel;
a data driver supplying a data voltage to a data line of the display panel;
a first voltage generator outputting a plurality of reference gamma voltages having different voltage levels;
a second voltage generator configured to generate a plurality of gamma adjustment voltages having voltage levels between the plurality of reference gamma voltages; and
and a node selection signal generator for outputting a plurality of node selection group signals,
The data driving unit has the data driving device for display according to any one of claims 7 to 10,
The second voltage generator includes a plurality of voltage division circuits for generating each of the plurality of gamma adjustment voltages, and each of the plurality of voltage division circuits includes a plurality of variable resistors. 12. The method of claim 11,
the first voltage generator generates the plurality of reference gamma voltages having voltage levels corresponding to each of a maximum grayscale voltage, an intermediate grayscale voltage, and a minimum grayscale voltage from among the plurality of grayscale voltages and supplies the generated reference gamma voltages to the grayscale voltage output unit Device. 13. The method of claim 12,
Each of the plurality of voltage divider circuits divides first and second driving voltages having different voltage levels through a plurality of series-connected variable resistors to generate a corresponding gamma adjustment voltage.

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