KR101032437B1 - Driving Method and Driving Device of Liquid Crystal Display - Google Patents

Abstract

The present invention relates to a driving method of a liquid crystal display device which can improve image quality by changing data corresponding to an image attribute.

A method of driving a liquid crystal display according to an embodiment of the present invention includes determining an image attribute of data input from the outside, selecting a lookup table corresponding to the image attribute, and changing a gray scale value of the data corresponding to the lookup table. It includes.

Description

Driving method and driving device of liquid crystal display device {Method and Apparatus of Driving Liquid Crystal Display}             

1 is a view showing a driving device of a conventional liquid crystal display device.

FIG. 2 is a diagram illustrating a gamma voltage supplied from a gamma voltage supply unit shown in FIG. 1.

3 is a view showing a driving device of a liquid crystal display according to another embodiment of the related art.

4 is a diagram illustrating a gamma voltage supplied from a gamma voltage supply unit illustrated in FIG. 3.

5 is a view showing a driving device of a liquid crystal display device according to an embodiment of the present invention;

6A to 6D are diagrams illustrating an example of a histogram generated by the image analyzer illustrated in FIG. 5.

FIG. 7 illustrates a lookup table included in the memory illustrated in FIG. 5; FIG.

FIG. 8 is a diagram illustrating a gamma voltage supplied from a gamma voltage supply unit illustrated in FIG. 5.

9A and 9B are views illustrating a process of updating a lookup table with the lookup table storage shown in FIG. 5;

10 is a view showing a driving device of a liquid crystal display device according to another embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

2,12,32 LCD panel 4,14,34 Data driver

6,16,36: Gate driver 8,18,38: Gamma voltage supply

10, 20, 40: timing controller 22, 24: gamma voltage unit

26,42 input unit 28,44 image analysis unit

30,52: control unit 46: memory

48: lookup table storage unit 50: data conversion unit

80: delay unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method and a driving device of a liquid crystal display device. More particularly, the present invention relates to a driving method and a driving device of a liquid crystal display device capable of improving image quality by changing data corresponding to image attributes.

The liquid crystal display device displays an image by adjusting light transmittance of liquid crystal cells according to a video signal. The liquid crystal display device is implemented in an active matrix type in which switching elements are formed in each cell, and is applied to display devices such as computer monitors, office equipment, and cellular phones. As a switching element used in an active matrix liquid crystal display device, a thin film transistor (hereinafter, referred to as TFT) is mainly used.

1 schematically shows a driving device of a conventional liquid crystal display.

Referring to FIG. 1, in a driving apparatus of a conventional liquid crystal display, m × n liquid crystal cells Clc are arranged in a matrix type, m data lines D1 to Dm and n gate lines G1 to A liquid crystal panel 2 having Gn intersected and a TFT formed at an intersection thereof, a data driver 4 for supplying a data signal to the data lines D1 to Dm of the liquid crystal panel 2, and gate lines. A data driver using a gate driver 6 for supplying a scan signal to the G1 to Gn, a gamma voltage supply unit 8 for supplying a gamma voltage to the data driver 4, and a synchronization signal supplied from the outside (4) and a timing controller 10 for controlling the gate driver 6 is provided.

The liquid crystal panel 2 includes a plurality of liquid crystal cells Clc disposed in a matrix at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn. Each TFT formed in the liquid crystal cell Clc supplies a data signal supplied from the data lines D1 to Dm to the liquid crystal cell Clc in response to a scan signal supplied from the gate line G. In addition, a storage capacitor Cst is formed in each of the liquid crystal cells Clc. The storage capacitor Cst is formed between the pixel electrode of the liquid crystal cell Clc and the front gate line, or is formed between the pixel electrode of the liquid crystal cell Clc and the common electrode line to maintain a constant voltage of the liquid crystal cell Clc. Let's do it. The liquid crystal cell Clc displays a predetermined image corresponding to the data signal supplied from the data lines D1 to Dm.

The timing controller 10 rearranges data supplied from the outside to match the resolution of the liquid crystal panel 2 and supplies the data to the data driver 4. The timing controller 10 generates a gate control signal GCS for controlling the gate driver 6 and a data control signal DCS for controlling the data driver 4 by using a synchronization signal supplied from the outside. do.

The gamma voltage supply unit 8 supplies a plurality of analog gamma voltages to the data driver 4. Here, the gamma voltage supply unit 8 generates a positive gamma voltage and a negative gamma voltage having a predetermined slope as shown in FIG. 2 in response to the characteristics of the liquid crystal panel 2.

The gate driver 6 sequentially supplies scan pulses to the gate lines G1 to Gn in response to the gate control signal GCS from the timing controller 10 to supply a horizontal signal to the liquid crystal panel 2. Select a line.

The data driver 4 converts the data supplied to itself in response to the data control signal DCS from the timing controller 10 to an analog gamma voltage (data signal) corresponding to the gray scale value, and this data signal. Is supplied to the data lines D1 to Dm. Here, the data driver 4 generates a data signal using any one of the analog gamma voltages corresponding to the data among the plurality of analog gamma voltages supplied from the gamma voltage supply unit 8.                         

In detail, the data driver 4 selects a voltage value of any one of the analog gamma voltages supplied from the gamma voltage supply unit 8 in response to the gray level of data as shown in FIG. 2. The selected voltage signal is supplied to the data lines D1 to Dm as a data signal. Then, the image of the luminance corresponding to the gray level of the data is displayed on the liquid crystal panel 2. However, such a conventional liquid crystal display device is difficult to display a vivid image because the voltage corresponding to the gray level is always selected regardless of the image characteristics of the data.

In order to overcome this problem, a liquid crystal display according to another exemplary embodiment of the present invention has been proposed as shown in FIG. 3.

Referring to FIG. 3, a driving apparatus of a liquid crystal display according to another exemplary embodiment includes m × n liquid crystal cells Clc arranged in a matrix, m data lines D1 to Dm, and n gates. Liquid crystal panel 12 having lines G1 through Gn intersected and TFTs formed at the intersection thereof, and data driver 14 for supplying a data signal to data lines D1 through Dm of the liquid crystal panel 12. And a gate driver 16 for supplying a scan signal to the gate lines G1 to Gn, a gamma voltage supply unit 18 for supplying a gamma voltage to the data driver 14, and a synchronization signal supplied from the outside. And a timing controller 20 for controlling the data driver 14 and the gate driver 16 by using.

The liquid crystal panel 12 includes a plurality of liquid crystal cells Clc arranged in a matrix at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn. Each TFT formed in the liquid crystal cell Clc supplies a data signal supplied from the data lines D1 to Dm to the liquid crystal cell Clc in response to a scan signal supplied from the gate line G. In addition, a storage capacitor Cst is formed in each of the liquid crystal cells Clc. The storage capacitor Cst is formed between the pixel electrode of the liquid crystal cell Clc and the front gate line, or is formed between the pixel electrode of the liquid crystal cell Clc and the common electrode line to maintain a constant voltage of the liquid crystal cell Clc. Let's do it. The liquid crystal cell Clc displays a predetermined image corresponding to the data signal supplied from the data lines D1 to Dm.

The timing controller 20 rearranges the data supplied from the outside to the data driver 14 according to the resolution of the liquid crystal panel 12 and controls the gate driver 16 and the data driver 14. The gate control signal GSC and the data control signal DCS are generated. The timing controller 20 supplies a control signal corresponding to the characteristic of the image to the gamma voltage supply unit 18.

To this end, the timing controller 20 may include an input unit 26 for receiving data and a synchronization signal from the outside, and an image analyzer 28 for determining characteristics of data supplied from the input unit 26. And a controller 30 for rearranging data supplied from the image analyzer 28 and generating a gate control signal GSC and a data control signal DCS using a synchronization signal. .

The input unit 26 receives data and a synchronization signal from the outside, and supplies the received data and the synchronization signal to the image analyzer 28.

The image analyzer 28 analyzes an image characteristic of the data supplied from the input unit 26 and supplies a control signal corresponding to the analyzed image characteristic to the gamma voltage supply unit 18. For example, when it is determined that the image characteristic of the supplied data is a dark image, the image analyzer 28 supplies a control signal corresponding to the dark image signal to the gamma voltage supply unit 18.

The controller 30 rearranges the data supplied from the image analyzer 28 and supplies the data to the data driver 14. In addition, the controller 30 controls the gate control signal GCS for controlling the gate driver 16 and the data control signal for controlling the data driver 14 using the synchronization signal supplied from the image analyzer 28. DCS).

The gamma voltage supply unit 18 supplies a plurality of analog gamma voltages to the data driver 14. The gamma voltage supply unit 18 includes a first gamma voltage unit 22 and a second gamma voltage unit 24 to supply data signals having different voltage levels in response to the same data.

As shown in FIG. 4, the first gamma voltage unit 22 supplies a predetermined first gamma voltage Gamma1 corresponding to the image characteristic of the data to the data driver 14. The second gamma voltage unit 24 supplies a second gamma voltage Gamma2 having a voltage value higher than the first gamma voltage Gamma1 to the data driver 14.

For example, when a control signal corresponding to a dark image signal is input from the image analyzer 28, the gamma voltage supply unit 18 supplies the second gamma voltage Gamma2 to the data driver 14. In other words, the gamma voltage supply unit 18 supplies a second gamma voltage Gamma2 having a high slope (high voltage difference) at low gray levels when a control signal corresponding to a dark image signal is input. When the second gamma voltage Gamma2 having a high gradient at a low gray level is supplied to the data driver 14, the difference in input-to-output ratio at a low gray level at the time of converting the data signal becomes large, thereby improving contrast.

The gate driver 16 sequentially supplies scan pulses to the gate lines G1 to Gn in response to the gate control signal GCS from the timing controller 20 to supply a horizontal signal to the liquid crystal panel 12. Select a line.

The data driver 14 converts the data supplied to itself in response to the data control signal DCS from the timing controller 20 into a data signal corresponding to the gray scale value, and converts the data signal into data lines (i. D1 to Dm). Here, the data driver 14 generates a data signal using the first gamma voltage Gamma1 or the second gamma voltage Gamma2 supplied from the gamma voltage supply unit 18. That is, the data driver 14 generates a data signal using the first gamma voltage Gamma1 or the second gamma voltage Gamma2 corresponding to the image characteristic of the data, and accordingly, in another conventional embodiment, Contrast is improved and a lively image can be displayed.

However, in the liquid crystal display according to another exemplary embodiment as described above, since the voltage value of the data signal is changed by using the gamma voltage supplied from the gamma voltage supply unit 18, different voltages may be supplied in response to various image characteristics. There is no problem. In detail, in order to display a lively image in the liquid crystal panel 12, gamma voltages having different voltage levels must be supplied corresponding to a plurality of image characteristics (for example, 100). However, in another conventional embodiment, a plurality of gamma voltage units must be added to supply gamma voltages at different voltage levels in response to a plurality of image characteristics.

Each of the gamma voltage units includes a plurality of voltage dividers in order to divide a predetermined voltage value to generate a plurality of voltage levels. That is, since each of the gamma voltage units includes a plurality of voltage divider resistors, the gamma voltage units occupy a predetermined area during installation, thereby limiting the number of gamma voltage units that may be included in the gamma voltage supply unit 18. In fact, in another conventional embodiment, four gamma voltage parts (positive polarity 2 and negative polarity 2) are provided inside the gamma voltage supply unit 18. As such, even though four gamma voltage units are installed in the gamma voltage supply unit 18, the gamma voltage supply unit 18 occupies a large area, which makes installation difficult. In addition, since the gamma voltage units having a plurality of voltage divider resistors have a high cost, the manufacturing cost increases further in another conventional embodiment.

Accordingly, an object of the present invention is to provide a driving method and a driving device of a liquid crystal display device which can improve image quality by changing data corresponding to an image attribute.

In order to achieve the above object, a method of driving a liquid crystal display device according to an embodiment of the present invention arranges data input from the outside into a histogram corresponding to a gray scale value, and generates at least one control signal corresponding to the arrangement form of the histogram. Determining an image attribute of data input from the image; selecting a lookup table corresponding to the image attribute; and changing a gray value of the data corresponding to the lookup table. The selecting may include storing a plurality of lookup tables in advance according to the arrangement of the histogram, and selecting at least one of the plurality of lookup tables in response to the control signal.

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The arranging of the histogram generates one histogram corresponding to the gray value of the red, green, and blue data.

Selecting at least one or more of the plurality of lookup tables corresponds to one histogram and selects one lookup table.

The step of changing the gray value of the data uses a single lookup table to change the gray value of the red, green, and blue data.

The arranging of the histogram generates three histograms corresponding to the gray values of the red, green, and blue data.

Selecting at least one or more of the plurality of lookup tables

Three lookup tables are selected corresponding to the one histogram.

The step of changing the gray scale value of the data uses three lookup tables to change the gray scale of the red, green, and blue data, respectively.

In the determining of the video attribute of the data, the image attribute is determined using data of one frame.

The step of changing the gray scale value of the data is to change the gray scale value of the data of the n-th frame by using a lookup table selected corresponding to the n-2 (n is a natural number) frame data.

In the determining of the image attribute of the data, the image attribute is determined using some data of one frame of data.

The step of changing the gray scale value of the data is to change the gray scale value of the data of the n-th frame by using a lookup table selected corresponding to the n-1 (n is a natural number) frame data.

The changing of the grayscale value of the data may further include delaying the n-th frame data until a lookup table corresponding to the n-th frame data is selected.

The arranging the histogram may include converting red, green, and blue data into luminance values, and generating a histogram by arranging the luminance values to correspond to grayscale values.

The method may further include converting the data having the gray level changed into a data signal that is an analog voltage value and supplying the data signal to the data lines.

According to an exemplary embodiment of the present invention, a method of driving a liquid crystal display device includes inputting data from an external source to a timing controller, acquiring image attributes of externally input data from a timing controller, and generating control signals corresponding to the identified image attributes. A step of supplying a lookup table from a memory installed outside the timing controller in response to a control signal, storing the lookup table inside the timing controller, and gradation of the data using the lookup table stored in the timing controller. Changing the value.

The determining of the image attribute may include generating at least one histogram of the data corresponding to the grayscale value in the image analyzer.

The memory stores a plurality of lookup tables corresponding to various arrangements of the histogram in advance.

The lookup table stored in the memory is updated according to the resolution of the liquid crystal panel and the driving environment of the liquid crystal panel.

The memory supplies at least one lookup table to a timing controller in response to a control signal among a plurality of lookup tables.

The method further includes generating a gamma voltage from the gamma voltage supply unit and converting data whose gray level value is changed in the data driver into a data signal using the gamma voltage.

The driving apparatus of the liquid crystal display of the present invention includes a memory in which a plurality of lookup tables are stored, and a timing controller for changing a gray value of data supplied from the outside using at least one lookup table stored in the memory, wherein the timing controller The control unit includes an input unit for receiving data supplied from the outside; An image analyzer for identifying an image attribute of data supplied from an input unit and generating a control signal corresponding to the identified image attribute; A lookup table storage unit storing at least one lookup table supplied from a memory; A data converter for changing a gray level value of data using at least one lookup table stored in a lookup table storage unit; And a control unit for relocating the data whose gradation value has been changed and supplying the data driver.

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The image analyzer generates one histogram by arranging red, green, and blue data corresponding to grayscale values, and generates a control signal corresponding to the arrangement of the generated histogram.

The memory supplies a lookup table of one of the plurality of lookup tables to the lookup table storage in response to a control signal.

The image analyzer generates three histograms by arranging red, green, and blue data corresponding to the respective gray levels, and generates three control signals corresponding to the three histograms.

The memory supplies three lookup tables of the plurality of lookup tables to the lookup table storage in response to the three control signals.

The image analyzer converts red, green, and blue data into luminance components, generates a histogram corresponding to the gray levels of the converted luminance components, and generates a control signal corresponding to the arrangement of the generated histograms.

The storage capacity of the lookup table storage unit is set smaller than that of the memory.

A gamma voltage supply unit receiving an analog gamma voltage; And a data driver for generating data signals by receiving data whose gray scale value is changed and selecting an analog gamma voltage corresponding to the gray scale value of the input data.

The image analyzer detects an image attribute using data of one frame.

The image analyzer detects an image attribute by using some data of one frame of data.

A delay unit is provided between the input unit and the data converter to delay data until the lookup table is supplied to the lookup table storage unit.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 5 to 10.

5 is a view showing a driving device of a liquid crystal display according to an embodiment of the present invention.

Referring to FIG. 5, in the driving apparatus of the liquid crystal display according to the exemplary embodiment of the present invention, m × n liquid crystal cells Clc are arranged in a matrix type, m data lines D1 to Dm and n gates are provided. The liquid crystal panel 32 where the lines G1 to Gn cross and the TFT is formed at the intersection thereof, and the data driver 34 for supplying a data signal to the data lines D1 to Dm of the liquid crystal panel 32. And a gate driver 36 for supplying a scan signal to the gate lines G1 to Gn, a gamma voltage supply unit 38 for supplying a gamma voltage to the data driver 34, and a synchronization signal supplied from the outside. And a timing controller 40 for controlling the data driver 34 and the gate driver 36 and changing the gradation value of the data in response to the image attribute.

The liquid crystal panel 32 includes a plurality of liquid crystal cells Clc disposed in a matrix at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn. Each TFT formed in the liquid crystal cell Clc supplies a data signal supplied from the data lines D1 to Dm to the liquid crystal cell Clc in response to a scan signal supplied from the gate line G. In addition, a storage capacitor Cst is formed in each of the liquid crystal cells Clc. The storage capacitor Cst is formed between the pixel electrode of the liquid crystal cell Clc and the front gate line, or is formed between the pixel electrode of the liquid crystal cell Clc and the common electrode line to maintain a constant voltage of the liquid crystal cell Clc. Let's do it. The liquid crystal cell Clc displays a predetermined image corresponding to the data signal supplied from the data lines D1 to Dm.

The gamma voltage supply unit 38 supplies a plurality of analog gamma voltages to the data driver 34. In fact, the gamma voltage supply unit 38 generates a positive gamma voltage and a negative gamma voltage having a predetermined slope as shown in FIG. 2 in response to the characteristics of the liquid crystal panel 32, and generates the generated positive gamma voltage and negative polarity. The gamma voltage is supplied to the data driver 34.

The gate driver 36 sequentially supplies scan pulses to the gate lines G1 to Gn in response to the gate control signal GCS supplied from the timing controller 40 to supply the data signal. Select the horizontal line.

The data driver 34 converts the data supplied to itself into a data signal corresponding to the gray scale value in response to the data control signal DCS supplied from the timing controller 40, and converts the data signal into data lines. It is supplied to (D1 to Dm). Here, the data driver 34 selects a specific gamma voltage among the plurality of gamma voltages from the gamma voltage supply unit 38 in response to the gray value of the data, and uses the selected gamma voltage as the data signal. Dm).

The timing controller 40 determines an image characteristic of data supplied from the outside and adjusts a gray value of the data so that an optimal image can be displayed in response to the image characteristic. In addition, the timing controller 40 rearranges and supplies the data to the data driver 34 according to the resolution of the liquid crystal panel 32, and controls the gate driver 36 and the data driver 34. A signal GCS and a data control signal DCS are generated.

To this end, the timing controller 40 includes an input unit 42, an image analyzer 44, a lookup table storage unit 48, a data converter 50, and a controller 52. In addition, the driving apparatus of the liquid crystal display of the present invention includes a memory 46 installed outside the timing controller 40 and connected to the image analyzer 44 and the lookup table storage 48.

The input unit 42 receives data and a synchronization signal from the outside. The input unit 42 that receives the data data supplies the data to the image analyzer 44.

The image analyzer 44 determines an image attribute of the data supplied from the input unit 42 and supplies a control signal corresponding to the identified image attribute to the memory 46. Various methods may be used to determine an image attribute of data in the image analyzer 44. For example, the image analyzer 44 may generate a histogram by arranging data of one frame or partial data of one frame so as to correspond to a gray level as illustrated in FIGS. 6A to 6D. Here, the shape of the histogram is variously displayed corresponding to the image attribute of the data. In addition, the image analyzer 44 may generate a histogram as shown in FIGS. 6A to 6D by converting one frame of R, G, and B data into luminance components. The image analyzer 44 separately analyzes image attributes of each of the red (R), green (G), and blue (B) data, and transmits three control signals to the memory 46 in response to the analyzed image characteristics. Can supply

The image analyzer 44 generating the histogram supplies a control signal corresponding to the histogram generated by the image analyzer 44 to the memory 46. In this case, the image analyzer 44 stores in advance the analysis data of a plurality of (eg, 100) histograms, and compares the histogram generated by the user with the previously stored analysis data to obtain the most similar (or identical) analysis data. The control signal corresponding to the control signal is supplied to the memory 46. The memory 46 may generate three lookup tables (LUTs) when the respective control signals corresponding to the red (R), green (G), and blue (B) data are input from the image analyzer 44. Update to storage 48.

As shown in FIG. 7, i (i is a natural number) lookup tables LUT1,..., And LuTi are stored in the memory 46. For example, 100 lookup tables (LUTs) are stored in the memory 46 to correspond to 100 image characteristics. The memory 46 supplied with the control signal from the image analyzer 44 supplies the lookup table LUT corresponding to the control signal to the lookup table storage 48.

The lookup table (LUT) stored in the memory 46 is determined experimentally so that an optimal image can be displayed in response to various image attributes. For example, the memory 46 stores a lookup table (LUT) in which an input-to-output ratio can be improved at low gray levels corresponding to data of a dark image attribute. The memory 46 stores a lookup table (LUT) in which an input-to-output ratio can be improved at high gray levels corresponding to data of bright image attributes. In fact, a plurality of lookup tables (LUTs) corresponding to various image attributes are stored in the memory 46. In addition, since the memory 46 is installed outside the timing controller 40, the contents of the lookup table LUT may be changed in response to user convenience, resolution and external conditions of the liquid crystal panel 32. That is, in the present invention, the gray level of the image displayed on the liquid crystal panel 32 can be easily adjusted by changing only the contents of the lookup table LUT stored in the memory 46.

Since a plurality of lookup tables (LUTs) are stored in the memory 46, the memory 46 is selected as a storage device having a high capacity. For example, the resolution of the input image is 10 bit and 100 different lookup tables (LUTs) are applied to the red (R), green (G), and blue (B) data. Assuming that the lookup table stores enough, about 3Mbit storage capacity is needed. Therefore, in the present invention, the memory 46 is provided outside the timing controller 40 so that the timing controller 40 can be integrated into one chip, and the look-up table necessary for changing the gray level of the data is provided inside the timing controller 40. A lookup table storage unit 48 is installed in which only the LUT) is stored.

The lookup table storage unit 48 stores the lookup table (LUT) supplied from the memory 46. For example, if one lookup table (LUT) is supplied from the memory 46 regardless of the red (R), green (G), and blue (B) data, the lookup table storage unit 48 provides one lookup table. (LUT) is stored. When three lookup tables (LUTs) are supplied from the memory 46 corresponding to each of red (R), green (G), and blue (B), three lookup tables (LUTs) are stored in the lookup table storage unit 48. do. Here, the lookup table storage unit 48 has less storage capacity than that of the memory 46 because only three lookup tables (LUTs) are stored.

The data conversion unit 50 modulates the gray value of the data supplied from the input unit 42 using the lookup table LUT stored in the lookup table storage unit 48. In detail, the look-up table LUT is stored in the gray value of the output data corresponding to the gray value of the input data. For example, if the output gradation value corresponding to the input gradation "1" is "2", the data conversion unit 50 outputs the data "2" when the data of the gradation of "1" is input. The gray value of the data is modulated to have a gray value of. When one lookup table (LUT) is stored in the lookup table storage unit 48, the data converter 50 uses one lookup table (LUT) for red (R), green (G), and blue (B) data. Modulate it. In addition, when three lookup tables (LUTs) are stored in the lookup table storage unit 48, the data converter 50 may convert red (R), green (G), and blue (B) data into different lookup tables (LUTs). Modulate using.

The controller 52 rearranges the data supplied from the data converter 50 and supplies the data to the data driver 34. In addition, the controller 52 generates and supplies a gate control signal GCS to the gate driver 36, and generates and supplies a data control signal DCS to the data driver 34.                     

The data driver 34 converts data supplied from the controller 52 into data signals and supplies the data signals to the data lines D1 to Dm. Here, the voltage value of the data signal generated by the data driver 34 is determined differently from the voltage value corresponding to the data input from the outside. For example, assuming that the original gray level of the data input to the timing controller 40 is "32", the data driver 34 should select a voltage of 8.2 [V] as the data signal as shown in FIG. . However, since the gray level of the data is changed using the lookup table LUT stored in the lookup table storage 48, the timing controller 40 selects a voltage different from 8.2 [V]. That is, assuming that the gray scale of "32" is changed to "40" in the timing controller 40, the data driver 34 selects a voltage of 8.4 [V] as the data signal. If the gray level of " 32 " is changed to " 28 " in the timing controller 40, the data driver 34 selects a voltage of 7.8 [V] as the data signal.

That is, in the present invention, a voltage value corresponding to the data using the gamma voltage supply unit 38 having one voltage curve for changing the gray level of the data input from the outside using the lookup table LUT. (Data signal) can be set in various ways. In particular, since the memory 46 stores a plurality of lookup tables corresponding to a plurality of image attributes, the memory 46 may display an optimal image corresponding to various image attributes. In addition, in the present invention, since the voltage value of the data signal can be changed by controlling the gray level of the data, the gamma voltage supply part 38 includes a gamma voltage part having one characteristic curve as shown in FIG. You can save money.                     

9A is a diagram illustrating a process of updating a lookup table with a lookup table storage.

9A, first, data supplied from the input unit 42 is supplied to the data conversion unit 50 without delay. That is, the data converter 50 sequentially processes data of n-1 frames (n-1 F), n frames (n F), n + 1 frames (n + 1), and n + 2 frames (n + 2). Supplied by. When data for n-1 frames (n-1 F) is supplied from the input unit 42, the image analyzer 44 analyzes image attributes of data for n-1 frames (n-1 F) and analyzes the data. The control signal corresponding to the generated video attribute is supplied to the memory 46. The memory 46 then updates the lookup table (LUT) corresponding to data for n-1 frames (n-1F) to the lookup table storage unit 48.

When data of n-1 frames (n-1 F) is stored in the lookup table storage unit 48, data for the n + 1th frame (n + 1) is supplied to the data conversion unit 50. Thereafter, the data conversion unit 50 changes the gray level of the data of the n + 1 th frame n + 1 using the lookup table LUT corresponding to the n-1 frame n-1 F. Then, the gray scale changed data is supplied to the controller 52. That is, in the present invention, the gray level of the data for n + 2 frames (n + 2 F) is changed by using the lookup table (LUT) corresponding to the data for n frames (n F). .

Thus, even if the gray level of the data of n + 2 frames (n + 2F) is changed by using the lookup table (LUT) corresponding to the data of n frames (n F), the liquid crystal panel ( In 32), an optimum image can be displayed. In fact, the data of multiple frames (for example, 60F) included in one second have a similar (or identical) image attribute to each other, and thus a lookup table corresponding to n frames (n F) of data. The gray level of data for n + 2 frames (n + 2F) can be changed using (LUT).

On the other hand, when the gray level of the data of n + 2 frames (n + 2F) is changed by using the lookup table (LUT) corresponding to the data of n frames (n F), the frame memory is used. There is no addition, and thus an increase in manufacturing cost can be prevented.

9B is a diagram illustrating another embodiment in which the lookup table is updated with a lookup table storage.

Referring to FIG. 9B, first, data supplied from the input unit 42 is supplied to the data conversion unit 50 without delay. That is, the data converter 50 sequentially processes data of n-1 frames (n-1 F), n frames (n F), n + 1 frames (n + 1), and n + 2 frames (n + 2). Supplied by. When data for n-1 frames (n-1 F) is supplied from the input unit 42, the image analyzer 44 analyzes image attributes of some data among data for n-1 frames (n-1 F). The control signal corresponding to the analyzed image attribute is supplied to the memory 46. In other words, the input unit 42 generates a histogram using only some of the data for n-1 frames (n-1 F) and analyzes the image attribute using the generated histogram.

The memory 46 supplied with the control signal updates the lookup table LUT corresponding to the control signal to the lookup table storage 48.

When the lookup table (LUT) corresponding to the data of the n-1 frame (n-1 F) is stored in the lookup table storage unit 48, the data for the nth frame (n + 1) is used by the data conversion unit 50. Is supplied. That is, since the time required for image analysis by the image analyzer 44 is shortened, the gray level of the data of the current frame n can be changed by using a frame n-1 delayed lookup table LUT.

In practice, the data conversion unit 50 changes the gray level of the data of the nth frame n by using the lookup table LUT corresponding to the n-1 frame n-1 F, and the gray level changed data. (data) is supplied to the control unit 52. That is, in the present invention, the gray level of the data of n + 1 frames (n + 1 F) is changed by using the lookup table (LUT) corresponding to the data of n frames (n F). .

Meanwhile, in the present invention, as shown in FIG. 10, a delay unit 80 may be additionally provided between the input unit 42 and the data conversion unit 50. The delay unit 80 delays the data until the image attribute is analyzed by the image analyzer 44 and the lookup table LUT corresponding to the analyzed image attribute is stored in the lookup table storage 48. Let's go. As described above, when the data is delayed in the delay unit 80, the gray level of the data of the nth frame may be changed by using a lookup table (LUT) corresponding to the image attribute of the nth frame.

As described above, according to the driving method and driving apparatus of the liquid crystal display according to the present invention, since the image attribute of the data is grasped and the gray scale value of the data is changed in correspondence with the identified image attribute, an optimal image is obtained from the liquid crystal panel. I can display it. In the present invention, since the voltage value of the data signal is adjusted by changing only the gray scale value of the data, the gamma voltage supply unit can generate one positive gamma voltage and a negative gamma voltage, thereby preventing an increase in manufacturing cost. can do. In addition, in the present invention, since the gray level of the data is changed by using a plurality of lookup tables that are determined experimentally so that an optimal image is displayed, it can easily correspond to image attributes of various data. In addition, in the present invention, by changing the contents of the lookup table stored in the memory, the liquid crystal panel can easily adjust the image of the liquid crystal panel corresponding to the resolution and the driving environment. In the present invention, since the image attribute result of the data of the n-1 or n-2 frames is applied to the data of the nth frame, an additional frame memory is not provided, and thus manufacturing cost is prevented from rising. can do.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (34)

Arranging data input from the outside into a histogram corresponding to the gray scale value, generating at least one control signal corresponding to the arrangement form of the histogram, and identifying an image property of the data input from the outside; Selecting a lookup table corresponding to the image attribute; Changing a gray value of the data corresponding to the lookup table; The selecting of the lookup table may include storing a plurality of lookup tables in advance in accordance with the arrangement of the histogram, and selecting at least one of the plurality of lookup tables in response to the control signal. A method of driving a liquid crystal display device, characterized in that. delete delete The method of claim 1, Deploying to the histogram is A method of driving a liquid crystal display device, characterized in that one histogram is generated corresponding to the gray value of red, green, and blue data. The method of claim 4, wherein Selecting at least one or more of the plurality of lookup tables And a lookup table is selected corresponding to the one histogram. The method of claim 5, Changing the gray value of the data And a gray value of the red, green, and blue data is changed using the one lookup table. The method of claim 1, Deploying to the histogram is 3. A method of driving a liquid crystal display device, characterized in that three histograms are generated corresponding to the gray level values of each of red, green, and blue data. The method of claim 7, wherein Selecting at least one or more of the plurality of lookup tables And three lookup tables are selected corresponding to the one histogram. The method of claim 8, Changing the gray value of the data And a gray level of the red, green, and blue data is changed using the three lookup tables. The method of claim 1, Identifying the image attribute of the data A method of driving a liquid crystal display device, characterized in that the image property is grasped using data of one frame. The method of claim 10, Changing the gray value of the data and a gray value of the data of the nth frame is changed using a lookup table selected in correspondence with the n-2 (n is a natural number) frame data. The method of claim 1, Identifying the image attribute of the data A method of driving a liquid crystal display device, characterized in that the image property is grasped using some data of one frame of data. The method of claim 12, Changing the gray value of the data and a gray value of the data of the nth frame is changed by using a lookup table selected corresponding to the n-1 (n is a natural number) frame data. The method of claim 1, Changing the gray value of the data and delaying the n-th frame data until the look-up table corresponding to the n-th frame data is selected. The method of claim 1, Deploying to the histogram is Converting red, green, and blue data into luminance values, And generating the histogram by arranging the luminance value so as to correspond to the gray scale value. The method of claim 1, Converting the data of which the gray value is changed into a data signal that is an analog voltage value; And supplying the data signal to the data lines. Inputting data into the timing controller from the outside; Identifying an image attribute of data input from the outside by the timing controller; Generating a control signal corresponding to the identified image attribute; Supplying a lookup table from a memory installed outside the timing controller in response to the control signal; Storing the lookup table inside the timing controller; And changing the gray value of the data by using the stored lookup table in the timing controller. The method of claim 17, Identifying the video attribute And generating at least one histogram of the data corresponding to the grayscale value in the image analyzer. The method of claim 18, And a plurality of lookup tables corresponding to various arrangements of the histogram are stored in the memory in advance. The method of claim 19, The look-up table stored in the memory is updated according to the resolution of the liquid crystal panel and the driving environment of the liquid crystal panel. The method of claim 19, And the memory supplies at least one lookup table to the timing controller in response to the control signal from among the plurality of lookup tables. The method of claim 17, Generating a gamma voltage from the gamma voltage supply unit; And converting data in which the gray scale value is changed into a data signal by using the gamma voltage in a data driver. A memory in which a plurality of lookup tables are stored; A timing controller configured to change a gray value of data supplied from the outside using at least one lookup table stored in the memory; The timing controller, An input unit for receiving data supplied from the outside; An image analyzing unit for identifying an image attribute of the data supplied from the input unit and generating a control signal corresponding to the identified image attribute; A lookup table storage unit storing at least one lookup table supplied from the memory; A data converter for changing a gray value of the data by using the at least one lookup table stored in the lookup table storage unit; And a control unit for rearranging the data whose gray level value is changed and supplying the data to the data driver. delete 24. The method of claim 23, And the image analyzing unit generates one histogram by arranging red, green, and blue data corresponding to the gray scale value, and generates a control signal corresponding to the arrangement of the generated histogram. 26. The method of claim 25, And the memory supplies a look-up table of a plurality of look-up tables to the look-up table storage in response to the control signal. 24. The method of claim 23, The image analyzer generates three histograms by arranging red, green, and blue data corresponding to respective gray levels, and generates three control signals corresponding to the generated three histograms. Drive system. 28. The method of claim 27, And the memory supplies three lookup tables of a plurality of lookup tables to the lookup table storage in response to the three control signals. 24. The method of claim 23, The image analyzer converts red, green, and blue data into luminance components, generates a histogram corresponding to the gray levels of the converted luminance components, and generates a control signal corresponding to the arrangement of the generated histograms. Driving device of liquid crystal display device. 24. The method of claim 23, And a storage capacity of the lookup table storage unit is set smaller than that of the memory. 24. The method of claim 23, A gamma voltage supply unit receiving an analog gamma voltage; And a data driver for inputting data whose gray scale value is changed and generating a data signal by selecting the analog gamma voltage in response to the gray scale value of the input data. 24. The method of claim 23, And the image analyzing unit grasps the image attribute using data of one frame. 24. The method of claim 23, And the image analyzing unit detects the image attribute by using some data of one frame of data. 24. The method of claim 23, And a delay unit disposed between the input unit and the data conversion unit to delay the data until the lookup table is supplied to the lookup table storage unit.

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