JP2009080499A - Liquid crystal display device, its driving device, and its driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the brightness of backlight while avoiding addition of circuits and restraining power consumption to a low level. <P>SOLUTION: A timing control part divides the RGB gradation level of an image into at least three levels (S100), counts and compares each number of picture extraction data of R, G, and B, respectively to which one picture frame is applied from outside as reference contained in the divided level (S200, S300, S400), adjusts the voltage applied to a backlight driving part in response to the comparison, and adjusts the brightness level. The timing control part adjusts the brightness level per one picture frame. As for a screen concentrating to locally high gradations (or screen requiring high contrast) or a screen with many high gradations as a whole (or screen requiring high brightness), the timing control part heightens the brightness of backlight while otherwise, it maintains the brightness normally (S210, S320, S410, S510). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, a driving device thereof, and a method thereof, and more particularly, for changing the luminance of a backlight and the gamma characteristic of a signal transmission system according to an input video state to be displayed by the liquid crystal display device. The present invention relates to a liquid crystal display device having an adaptive brightness enhancement function, a driving device thereof, and a method thereof. In order to reduce misunderstandings of terms in the description, in principle, an analog signal applied to a display device is described as an image signal, and an original signal (input signal) to be displayed is described as a video signal. The original signal is generally in a digital format, and becomes an image signal by DA conversion (main part of gradation voltage generation).

  Generally, CCFL (Cold Cathode Fluorescent Lamp) used as a light source for LCD has an inversely proportional relationship between luminance and life in terms of its characteristics. In other words, the lifetime is shortened when driving with a high current to increase the luminance, but on the other hand, it is difficult to achieve a high luminance because the driving must be performed with a low current to extend the lifetime. However, in reality, high brightness and long life are required at the same time in most cases from the viewpoint of product application.

  In order to meet such demands, when a screen that requires special high brightness is displayed when driving at a certain brightness in a general LCD screen state, the backlight is temporarily A technology is applied in which the active area is expanded in accordance with the luminance to be displayed by passing a high current through the lamp.

  In addition, the amount of current used by the display element varies depending on the image displayed on the screen of the LCD itself. For example, in a normally white mode in which liquid crystal molecules are rearranged in the direction of an electric field with application of a voltage to block incident light, the power consumed by the panel generally increases as the number of bright pixels on the screen increases. On the other hand, the power consumed by the panel tends to increase as the number of dark pixels increases. Using such a tendency, a method of controlling the current value of the lamp in conjunction with the power consumed by the panel is mainly used.

  However, when such a technique is applied, the current consumed by the panel must be detected, and this must be modified to match the variable range of the luminance control signal of the power converter that drives the backlight. There is a problem that an additional circuit must be formed.

  In addition, since the luminance is controlled for all screens, there is a problem that power consumption must be higher than when the luminance is controlled only for the screens that need to be controlled.

  Therefore, the present invention is to solve such a conventional problem, and an object of the present invention is to determine the luminance of the backlight according to the gradation level of video data to be displayed in units of one video frame. It is an object of the present invention to provide a liquid crystal display device having an adaptive brightness adjustment function for controlling the brightness.

  Another object of the present invention is to provide a driving device for a liquid crystal display device having an adaptive brightness adjustment function for controlling the brightness of a backlight in accordance with the gradation level of video data to be displayed.

  Another object of the present invention is to provide a driving method of a driving device for a liquid crystal display device having the adaptive luminance adjustment function.

  A liquid crystal display device according to one aspect of the present invention includes an LCD panel, a backlight unit that illuminates the LCD panel with a luminance corresponding to a backlight driving voltage, and a driving device. The driving device includes a gate driver that outputs a scanning signal to the LCD panel, a data driver that outputs an image signal to the LCD panel, a power converter that outputs a backlight driving voltage to the backlight unit, and an external input. The power converter outputs a signal for outputting a scanning signal to the gate driver, and outputs a signal for outputting an image signal to the data driver according to the video signal and timing signal to be outputted, and the power converter Has a timing control unit for outputting a backlight control signal for instructing the level of the backlight drive voltage.

  The timing control unit includes a video inquiry unit and a luminance control unit. The video inquiry unit checks the characteristics of the video signal to determine whether the video type indicated by the video signal is a moving video or a stop video, and the determined video type is a stop video In this case, a first video discrimination signal is output, and when the discriminated video type is a moving video, a second video discrimination signal is output. When the first video determination signal is input, the luminance control unit outputs a backlight control signal for instructing a level of the backlight driving voltage maintained constant, and inputs the second video determination signal In this case, a backlight control signal for instructing the level of the backlight drive voltage that is adjusted according to the level of luminance required by the video signal is output.

  The video inquiry unit includes a storage unit, a frame coefficient unit, a data comparison unit, and a video discrimination unit. The storage unit stores the video signal. The frame coefficient unit extracts a first data set corresponding to each of a plurality of unit cells included in the screen of the LCD panel from the kth frame of the video signal, stores the first data set in the storage unit, and (k + N ) Extract a second data set corresponding to each of the plurality of unit cells from the second frame, store the second data set in the storage unit, and output the first data set and the second data set from the storage unit. . The data comparison unit compares the first data set and the second data set corresponding to the same unit cell, and outputs a first signal if they are equal and outputs a second signal if they are different. To do. The video discriminating unit determines the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. In response, either the first video discrimination signal or the second video discrimination signal is output.

  The video discriminating unit includes the data comparison unit indicating a comparison result between the first data set and the second data set corresponding to each of the unit cells arranged in the first direction among the plurality of unit cells. It is checked whether all the signals are the second signals, and if all the checked signals are the second signals, a second video discrimination signal is output, and any one of the checked signals is the first signal. If it is not two signals, it is checked whether or not the number of second signals included in the series of signals from the data comparison unit is equal to or greater than a predetermined number, and the number of second signals is equal to or greater than the predetermined number. If it is, the second video discrimination signal is output, and if it is less than the predetermined number, the first video discrimination signal is output.

  A driving method of a liquid crystal display device according to one aspect of the present invention is a method for driving a liquid crystal display device that includes an LCD panel and a backlight unit that illuminates the LCD panel, and is provided in a screen of the LCD panel. Selecting a plurality of unit cells from, and extracting and storing a first data set corresponding to each of the plurality of unit cells from a k-th frame of a video signal input to the liquid crystal display device from the outside. , Extracting and storing a second data set corresponding to each of the plurality of unit cells from the (k + N) th frame of the video signal, the first data set corresponding to the same unit cell, and the second data set. Comparing the data sets and setting the first value as the first comparison value if they are equal, and setting the second value as the first comparison value if they are different; Checking whether or not the first comparison value is the second value for all of the unit cells arranged in the first direction among the unit cells, the first comparison value for all of the unit cells arranged in the first direction. Is a second value, the step of determining that the type of video indicated by the video signal is a moving video, and the first comparison value is not the second value for any of the unit cells arranged in the first direction Checking whether or not the number of first comparison values, which are second values among the first comparison values for all of the plurality of unit cells, is greater than or equal to a predetermined number, the number of the first comparison values Is greater than or equal to the predetermined number, it is determined that the video type indicated by the video signal is a moving video, and when the number of the first comparison values is less than the predetermined number, Determining that the type of video to be displayed is a stop video; Is determined to be a moving image, the image is displayed on the LCD panel while controlling the luminance of the backlight unit in units of frames according to the luminance level required by the video signal. And displaying the image on the LCD panel while maintaining the brightness of the backlight unit constant when it is determined that the type of the image indicated by the image signal is a stop image.

  A liquid crystal display device according to another aspect of the present invention includes an LCD panel, a backlight unit that illuminates the LCD panel with a luminance corresponding to a backlight driving voltage, and a driving device. The driving device includes a gate driver that outputs a scanning signal to the LCD panel, a data driver that outputs an image signal to the LCD panel, a power converter that outputs a backlight driving voltage to the backlight unit, and an external input. The power converter outputs a signal for outputting a scanning signal to the gate driver, and outputs a signal for outputting an image signal to the data driver according to the video signal and timing signal to be outputted, and the power converter Has a timing control unit for outputting a backlight control signal for instructing the level of the backlight drive voltage.

  The timing control unit includes a video inquiry unit and a luminance control unit. The video inquiry unit checks the characteristics of the video signal to determine whether the video type indicated by the video signal is a moving video or a stop video, and the determined video type is a stop video In this case, a first video discrimination signal is output, and when the discriminated video type is a moving video, a second video discrimination signal is output. When the first video determination signal is input, the luminance control unit outputs a first backlight control signal for instructing a level of the backlight driving voltage maintained constant, and the second video determination signal Is input, a second backlight control signal for instructing the level of the backlight driving voltage adjusted in accordance with the level of luminance required by the video signal is output.

  The video inquiry unit includes a storage unit, a frame coefficient unit, a data comparison unit, and a video discrimination unit. The storage unit stores the video signal. The frame coefficient unit extracts a first data set corresponding to each of a plurality of unit cells from the kth frame of the video signal and stores the first data set in the storage unit, and the plurality of unit data from the (k + N) th frame. A second data set corresponding to each unit cell is extracted and stored in the storage unit, and the first data set and the second data set are output from the storage unit. The data comparison unit compares the first data set and the second data set corresponding to the same unit cell, and outputs a first signal if they are equal and outputs a second signal if they are different. To do. The video discriminating unit determines the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. In response, either the first video discrimination signal or the second video discrimination signal is output.

  The video discriminating unit checks whether or not the series of signals are all second signals, and if the checked signals are all second signals, outputs a second video discriminating signal. If any of the received signals is not the second signal, it is checked whether or not the number of the second signals included in the series of signals is equal to or greater than a predetermined number, and the number of the second signals is When the number is greater than or equal to the predetermined number, the second video discrimination signal is output, and when the number is less than the predetermined number, the first video discrimination signal is output.

  The timing control unit divides gradation data included in one frame of the video signal into at least three groups according to the gradation level, and the first group having the highest gradation level and the lowest gradation level. The gradation data is counted for each of the second groups, and the number of gradation data included in the first group is equal to or greater than the first ratio with respect to the total number of gradation data included in one frame of the video signal. And the number of gradation data included in the second group is equal to or greater than the second ratio with respect to the total number, the level of the backlight driving voltage indicated by the second backlight control signal is set. The gradation level indicated by the gradation data having a low gradation level among the gradation data included in the video signal is converted to be lower than usual.

  A driving method of a liquid crystal display device according to another aspect of the present invention is a method for driving a liquid crystal display device including an LCD panel and a backlight unit that illuminates the LCD panel. Selecting a plurality of unit cells from the screen; (b) selecting a first data set corresponding to each of the plurality of unit cells from the k-th frame of the video signal input to the liquid crystal display device from the outside. Extracting and storing; (c) extracting and storing a second data set corresponding to each of the plurality of unit cells from the (k + N) th frame of the video signal; and (d) the same unit cell. The first data set corresponding to the first data set is compared with the second data set, and if they are equal, the first value is set as the first comparison value, and if they are different, the second value is set as the first comparison value. As value (E) determining that the video type indicated by the video signal is a moving video when the first comparison value is the second value for all of the plurality of unit cells; If the first comparison value is not the second value for any of the plurality of unit cells, the step of checking whether or not the number of the first comparison values, which are the second values, is equal to or greater than a predetermined number, (g) When the number of first comparison values is greater than or equal to the predetermined number, it is determined that the video type indicated by the video signal is a moving image, and when the number of first comparison values is less than the predetermined number Determining that the video type indicated by the video signal is a stop video; (h) luminance determined by the video signal when the video type indicated by the video signal is determined to be a moving video; The brightness of the backlight unit according to the height of each frame Controlling, displaying the video on the LCD panel; and (i) controlling the brightness of the backlight unit to be constant when it is determined that the video type indicated by the video signal is a stop video. And displaying an image on the LCD panel.

  In step (h), (h-1) gradation data included in one frame of the video signal is divided into at least three groups according to the gradation level, and the first group and the highest gradation level are divided. (G-2) counting gradation data for each of the second group having the lowest tone level; (h-2) the number of gradation data included in the first group included in one frame of the video signal; Checking whether the total number of tone data is greater than or equal to a first ratio; (h-3) the number of gradation data included in the first group is greater than or equal to the first ratio relative to the total number If there is, a step of checking whether the number of gradation data included in the second group is equal to or greater than a second ratio with respect to the total number, and (h-4) included in the second group The total number of gradation data If it is the second ratio or for comprising the step of converting the luminance of the backlight unit higher than normal levels, the gradation level indicated by the gradation level lower gray scale data even lower.

  A liquid crystal display device according to still another aspect of the present invention includes an LCD panel, a backlight unit that illuminates the LCD panel with a luminance corresponding to a backlight driving voltage, and a driving device. The driving device includes a gate driver that outputs a scanning signal to the LCD panel, a data driver that outputs an image signal to the LCD panel, a power converter that outputs a backlight driving voltage to the backlight unit, and an external input. The power converter outputs a signal for outputting a scanning signal to the gate driver, and outputs a signal for outputting an image signal to the data driver according to the video signal and timing signal to be outputted, and the power converter Has a timing control unit for outputting a backlight control signal for instructing the level of the backlight drive voltage.

  The timing control unit includes a video inquiry unit and a luminance control unit. The video inquiry unit checks the characteristics of the video signal to determine whether the video type indicated by the video signal is a moving video or a stop video, and the determined video type is a stop video In this case, a first video discrimination signal is output, and when the discriminated video type is a moving video, a second video discrimination signal is output. When the first video determination signal is input, the luminance control unit outputs a backlight control signal for instructing a level of the backlight driving voltage maintained constant, and inputs the second video determination signal In this case, a backlight control signal for instructing the level of the backlight drive voltage that is adjusted according to the level of luminance required by the video signal is output.

  The video inquiry unit includes a storage unit, a frame coefficient unit, a data comparison unit, and a video discrimination unit. The storage unit stores the video signal. The frame coefficient unit extracts a first data set corresponding to each of a plurality of unit cells included in the screen of the LCD panel from the kth frame of the video signal, stores the first data set in the storage unit, and (k + N ) The second data set corresponding to each of the plurality of unit cells is extracted from the first frame and stored in the storage unit, and the first direction among the plurality of unit cells is extracted from the (k + N + M) th frame. A third data set corresponding to each of the unit cells arranged in a row is extracted and stored in the storage unit, and the first data set, the second data set, and the third data set are output from the storage unit. . The data comparison unit compares the first data set and the second data set corresponding to the same unit cell, or compares the second data set and the third data set corresponding to the same unit cell. If both are equal, the first signal is output, and if they are different, the second signal is output. The video discriminating unit determines the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. In response, either the first video discrimination signal or the second video discrimination signal is output, and the comparison result between the second data set and the third data set is obtained for each of the unit cells arranged in the first direction. Depending on whether each of the signals from the data comparison unit is a first signal or a second signal, the frame coefficient unit includes the first data set, the second data set, and the third data. At least one of the sets is extracted again.

  Whether the video discriminating unit is the second signal for all the series of signals from the data comparing unit indicating the comparison result between the first data set and the second data set for all of the plurality of unit cells. If all the checked signals are second signals, a second video discrimination signal is output. If any of the checked signals is not a second signal, the series of signals are output. Whether the number of second signals included in the signal is equal to or greater than a predetermined number, and if the number of the second signals is equal to or greater than the predetermined number, a second video discrimination signal is output, If the number is less than the predetermined number, the first video discrimination signal is output.

  The video discriminating unit is configured such that a series of signals from the data comparing unit indicating the comparison results between the second data set and the third data set for all the unit cells arranged in the first direction are all second signals. If the video signal has already been determined to be a moving image, the third data set is repeated in the frame coefficient section every time the video signal advances M frames. A series of signals from the data comparison unit indicating the comparison results between the second data set and the third data set for all of the unit cells arranged in the first direction are extracted at least twice. If the signal is repeated, the frame coefficient unit extracts all of the first data set, the second data set, and the third data set again.

  In the video discriminating unit, a signal from the data comparing unit indicating a comparison result between the second data set and the third data set for any of the unit cells arranged in the first direction is not the second signal. In this case, among the unit cells arranged in the first direction, the signal from the data comparison unit indicating the comparison result between the second data set and the third data set for the unit cell at the intermediate point is the first signal. And if it is already determined that the video type indicated by the video signal is a stop video, the frame coefficient portion repeatedly extracts the third data set every time the video signal advances M frames, At least twice, the signal from the data comparison unit indicating the comparison result between the second data set and the third data set for the unit cell at the intermediate point is the first signal. After the loop is possible, the Frame coefficient unit, the first data set, the second data set, and all is extracted again the third data set.

  A driving method of a liquid crystal display device according to still another aspect of the present invention is a method for driving a liquid crystal display device including an LCD panel and a backlight unit that illuminates the LCD panel, and (a) the LCD panel Selecting a plurality of unit cells from the screen of (b), (b) a first data set corresponding to each of the plurality of unit cells from the k-th frame of the video signal input to the liquid crystal display device from the outside. (C) extracting and storing a second data set corresponding to each of the plurality of unit cells from the (k + N) th frame of the video signal; and (d) the same unit. The first data set corresponding to the cell and the second data set are compared, and if they are equal, the first value is set as the first comparison value, and if they are different, the second value is set to the first value. Comparison value and (E) determining that the video type indicated by the video signal is a moving video when the first comparison value is the second value for all of the plurality of unit cells; (f) If the first comparison value is not the second value for any one of the plurality of unit cells, checking whether the number of the first comparison values as the second value is equal to or greater than a predetermined number; (g) When the number of the first comparison values is equal to or greater than the predetermined number, it is determined that the video type indicated by the video signal is a moving image, and the number of the first comparison values is less than the predetermined number (H) determining that the video type indicated by the video signal is a stop video; and (h) if the video type indicated by the video signal is determined to be a moving video, the video signal is requested by the video signal. The brightness of the backlight unit is set to one frame according to the brightness level. (I) When it is determined that the video type indicated by the video signal is a stop video, the luminance of the backlight unit is controlled to be constant. (J) displaying a video on the LCD panel; (j) from the (k + N + M) th frame of the video signal, a third data set corresponding to each of the unit cells arranged in the first direction among the plurality of unit cells. Is extracted and compared with the second data set corresponding to the same unit cell, and if they are equal, the first value is set as the second comparison value, and if they are different, the second value is set as the second comparison value. (K) determining that the second comparison value is the second value for all the unit cells arranged in the first direction, and that the video type indicated by the video signal is already a moving video. If it is While maintaining the determination, the video signal is further advanced by M frames and the step (j) is repeated, and the second comparison value is the second value for all the unit cells arranged in the first direction at least twice. Is repeated, the process returns to the step (b) from the next frame of the video signal, and (l) the second comparison value is not the second value for any of the unit cells arranged in the first direction. In this case, among the unit cells arranged in the first direction, it is determined that the second comparison value for the unit cell at the intermediate point is the first value, and that the video type indicated by the video signal is already the stop video. If so, the video signal is further advanced by M frames while the determination is maintained, and the step (j) is repeated, and the second comparison value for the unit cell at the intermediate point is the first value at least twice. Is repeated From the next frame of the video signal, returning to the step (b), and (m) among the unit cells arranged in the first direction, the second comparison value is the second comparison value for the unit cell at the intermediate point. If the second comparison value is not the second value for any other unit cell, the process returns to step (b) from the next frame of the video signal. including.

  According to such a liquid crystal display device and its driving device and method, it is more suitable for the grayscale voltage level of the video data than the conventional technique of detecting the current value of the video data and adjusting the luminance of the backlight. A higher contrast can be realized by controlling the luminance of the backlight.

  Further, the luminance level of the backlight can be controlled by selecting a plurality of specific portions from the display screen and tracking and observing changes in the video data.

  Hereinafter, examples will be described so that those having ordinary knowledge can easily implement the present invention.

  FIG. 1 is a diagram for explaining a liquid crystal display device according to an embodiment of the present invention.

  Referring to FIG. 1, a liquid crystal display device according to an embodiment of the present invention includes a liquid crystal display module 100 including an LCD panel 110 and a backlight unit 120, a timing control unit 200, a gate driver 300, a data driver 400, and a backlight. A liquid crystal display module driving device including a power converter 500 and a grayscale voltage generator 600 is included.

  The LCD panel 110 is composed of a plurality of pixel electrodes configured in an mxn matrix type, and each pixel electrode is provided with a switching element. When a gate voltage (or scanning signals G1, G2,..., Gn) provided from the gate driver 300 is applied to the switching element of the corresponding pixel through the gate line, the data voltage provided from the data driver 400 through the data line. In response to (or pixel signals, D1, D2,..., Dm), the corresponding pixel electrode is driven, and an image is displayed using the backlight unit 120 on the back of the LCD panel as a light source.

  The timing control unit 200 includes a data coefficient unit 210, a first summation unit 220, a second summation unit 230, a comparison unit 240, a memory control unit 250, and an SRAM unit 260, and is particularly relevant to the description of one embodiment of the present invention. In other words, the gradation data of each RGB is separated into three gradation level groups and counted in one frame unit.

  Roughly described, the timing control unit 200 applies a drive voltage higher than a normal drive voltage to the backlight power converter 500 when a large number of bright gradation video data is included in one counted frame. As described above, the power converter such as the backlight power converter 500 including the inverter or the like is controlled to increase the luminance.

  In addition, when a large amount of dark grayscale video data is included in one counted frame, a normal drive voltage is applied to the backlight power converter 500 to maintain brightness and brightness while the liquid crystal display The gradation voltage applied to the module 100 is adjusted to control the darker luminance level.

  More specifically, the data coefficient unit 210 includes an R data coefficient unit 212, a G data coefficient unit 214, and a B data coefficient unit 216, each of which includes one data discrimination unit, two counters, and two adders. The number of RGB gradation data of the image applied from an external graphic controller (not shown) is counted, and the high-level RGB gradation data (R3, G3, B3) is counted. 1 is output to the summing unit 220, or low-level gradation data (R1, G1, B1) is counted and output to the second summing unit 230.

  Then, the data discrimination | determination part 212-1, the 1st counter 212-3, the 2nd counter 212-5, the 1st adder 212-7, and the 2nd adder 212-9 which comprise R data coefficient part 212 are mentioned as an example. The present invention will be described in more detail.

  The data discriminating unit 212-1 checks the gradation level of the input R video data, and if it is discriminated that the R data has a high gradation level, the data discriminating unit 212-1 adds it to the first counter 212-3, When it is checked that the R data is the key level, it is added to the second counter 212-5.

  The first counter 212-3 receives and counts the high gradation level R data provided from the data determination unit 212-1 and provides the counted number to the first summer 212-7. -5 receives and counts the low gray level R data and provides the counted number to the second summer 212-9.

  The first summer 212-7 calculates the number of R data having a high gradation level for each frame period according to one vertical synchronization signal (Vsync) according to the count number provided from the first counter 212-3. The second adder 212-9 adds the count number provided from the second counter 212-5 to one frame period according to one vertical synchronization signal (Vsync). The number of R data having a low gradation level is summed up every time and output to the second summing unit 230.

  The first summing unit 220 receives the number of RGB video data of high gradation levels from the data coefficient unit 210 in units of one frame, adds them to the comparison unit 240, and the second summing unit 230 The number of RGB image data of low gradation levels is received from the coefficient unit 210 in units of one frame, added together, and provided to the comparison unit 240.

  The comparison unit 240 includes the number of high gradation level RGB data input from the first summation unit 220 and the low gradation level RGB input from the second summation unit 230 for each frame period. When it is determined that the number of video data for each of RGB with a high gradation level is relatively larger than the number of video data for each of RGB with a low gradation level by comparing with the number of video data, the backlight A luminance control signal 241 for controlling the power converter 500 to apply a high drive voltage is output to increase the luminance. In the opposite case, a luminance control signal 241 for applying a normal driving voltage to the backlight power converter 500 is output.

  At this time, when the luminance control signal 241 for applying a normal driving voltage is output, low gradation data is converted to a lower gradation in order to compensate for the bright backlight. The brightness control signal 241 to be controlled is output to the memory control unit 250.

  The memory control unit 250 provides the RGB unit digital video data provided from a graphic controller (not shown) to the SRAM unit 260. If video data in a specific range is displayed, low-gradation RGB video data is compensated for lower backlight RGB video data (R ′, R ′, G ′, B ′) are extracted and output to the SRAM unit 260. Here, the ROM 255 used as a look-up table (LUT) has been described as an example in which the ROM 255 is installed outside the timing control unit 200. I will.

  The SRAM unit 260 includes a first SRAM 262 that stores R data provided from the memory control unit 250, a second SRAM 264 that stores G data, and a third SRAM 266 that stores B data. , G ′, B ′) and provide the adapted RGB video data (RA, GA, BA) to the data driver 400.

  At this time, when the luminance control signal 241 having a low gradation level is input from the comparison unit 240, the low gradation data is converted to a lower gradation in order to compensate for the bright backlight. The control signal 251 is output to the gradation voltage generator 600.

  The gradation voltage generator 600 forms a gradation in conjunction with the number of bits of R, G, and B data applied from an external graphic controller and applies the gradation to the data driver 400. The gate driver 300 is connected to the data driver 400. It plays a role of guiding so that data transmitted to the pixel can be transmitted to the pixel. Of course, if a signal 251 for controlling the conversion to a lower gradation is input from the memory control unit 250 of the timing control unit 200, a gradation lower than the normal gradation is generated and output to the date driver 400. To do.

  The data driver 400 is also referred to as a source driver, but receives each of the adapted RGB video data (RA, GA, BA) applied from the timing control unit 200, stores it in a shift register (not shown), and stores the data Is transmitted to the LCD panel 110, a voltage corresponding to each data is selected by D / A conversion and the voltage is transmitted to the LCD panel 110.

  As described above, when the backlight of the liquid crystal display device is driven, a screen that concentrates locally on a high gradation (or a screen that requires high contrast) or a screen that has a high overall gradation (or In the case of a screen that requires high brightness, the brightness of the backlight can be increased, and in other cases, the brightness can be maintained normally to further increase the contrast during video display.

  Hereinafter, the operation of the liquid crystal display device having the adaptive brightness adjustment function according to the present invention will be described in more detail.

  FIG. 2 is a diagram for explaining a general number of data by gradation.

  As shown in FIG. 2, the gradation distribution of an image includes the number of data having a specific gradation (for example, 45/64 gradation) or more and data having another specific gradation (for example, 32/64 gradation) or less. It can be easily determined by counting and comparing the number. Here, the 45/64 gradation or the 32/64 gradation is a gradation in which each luminance becomes 1/2 or 1/4 as compared with the maximum luminance when the gamma value of the display is 2. Those skilled in the art will be able to change such values.

  An example of a method for determining a video whose luminance should be increased will be described. First, the number of data of 45/64 gradations or more is 5% or 3%, and the number of data of 32/64 gradations or more is first. In the case of 10 times or more, the luminance of the backlight and low gradation data are subjected to gradation conversion.

  Hereinafter, an embodiment will be described in which the luminance of the backlight according to the present invention is changed in accordance with the image to be driven and is driven in four stages.

  FIG. 3 is a flowchart for explaining a liquid crystal display method having an adaptive brightness adjustment function according to an embodiment of the present invention.

  Referring to FIG. 3, first, the gradation data of the video is divided into groups of A for 45/64 gradations or more, B for 45/64 to 32/64 gradations, and C for 32/64 gradations or less. Then, the gradation numbers are counted (step S100).

  Next, it is checked whether A / (A + B + C) is 0.08 or more and C / A satisfies the condition of 5 or more (step S200). The backlight lamp current value or the on / off duty ratio of the lamp current is controlled so as to be 600 nits (or cd / m2) (step S210), and gradation conversion of low gradation data is performed (step S220). .

  In step S200, if A / (A + B + C) is 0.08 or more and C / A does not satisfy the condition of 5 or more, A / (A + B + C) is 0.05 or more and C / A is 10 or more. It is checked whether or not the condition is satisfied (step S300), and if the condition is satisfied, the backlight lamp current value or the lamp current on / off duty ratio is controlled so that the brightness of full white is 450 nits. In step S310, gradation conversion of low gradation data is performed (step S320).

  If the second condition is not satisfied in step S300, it is checked whether A / (A + B + C) is 0.03 or more and C / A satisfies 20 or more (step S400). When the three conditions are satisfied, the lamp current value of the backlight or the on / off duty ratio of the lamp current is controlled so that the brightness of full white is 300 nits (step S410), and gradation conversion of low gradation data is performed. Implement (step S420).

  If the third condition is not satisfied in step S400, the backlight lamp current value or the on / off duty ratio of the lamp current is controlled so that the full white luminance is 200 nits (step S510). The tone conversion of tone data is performed (step S520).

  As described above, the gradation data of the video is divided into A (45/65 gradations), B (45/64 gradations to 32/64 gradations), and C (32/64 gradations or less). The number of gradations is counted, the numbers of A, B, and C are compared, and the brightness is controlled in four stages to control the brightness of the brightness. The luminance classification is 45/64 gradation and 32/64 gradation when the gradation is 1/2 and 1/4 with respect to the case where the gamma value is 2, respectively. There are, but not limited to such numbers.

  Actually, in the case of an LCD panel, when the luminance of the backlight increases, the luminance of the low gradation pixels also increases at the same time. Therefore, unless these gradations are further reduced, the same brightness as when the backlight does not increase the brightness cannot be maintained. It can be said that the range has increased.

  Now, an example of gradation change will be described with reference to FIGS. 4 and 5 by taking two of the four steps (when the luminance is 450 nits and 200 nits) as an example.

  FIG. 4 is a diagram for explaining the luminance by gradation before tuning and the luminance by gradation after tuning according to the present invention.

  As shown in FIG. 4, when there is no gradation correction of the LCD panel, the gradation brightness when the backlight brightness is adjusted to the panel brightness of 200 nits and 450 nits and the gradation when the gradation tuning is performed. Brightness.

  When the tone tuning is performed without correcting the tone of the LCD panel, the same brightness as before the brightness becomes brighter at the lower tone, even though the brightness of the backlight becomes brighter. Can be confirmed.

  FIG. 5 is a diagram illustrating gradation tuning in consideration of a change in luminance of the backlight according to the present invention.

  As shown in FIG. 5, the dark portion is further darkened, and at the same time, the brightness of the bright portion is kept the same, so that the contrast during video display can be further increased.

  That is, the contrast at 200 nits is 350 to 400: 1, but the effective contrast at the time of actual moving image display is about 1000: 1 at the maximum.

  As described above, in a moving image, a certain number of video data is generally concentrated in a high gradation, but most of the video data is concentrated in the vicinity of a low gradation. In order to make an image with a large number of gradations appear more conspicuous, in one embodiment of the present invention, an increase in brightness of the backlight is controlled. At the same time, in the embodiment of the present invention for low gradation video data, the data is changed to a gradation lower than the original gradation to compensate for the increased backlight luminance. .

  In the case of video data having a continuous gradation distribution other than such video, it is not necessary to increase the brightness of the backlight regardless of power consumption.

  Also, when a luminance control signal is sent to the backlight power converter through a simple calculation of digital data, it is not necessary to configure a separate circuit according to an embodiment of the present invention. There is no such additional cost.

  As described above, when trying to reproduce a moving image such as a TV or a DVD on the liquid crystal display device, the embodiment of the present invention is very effective. However, generally expensive LCD TV (TV / monitor combined use) has the role of PC TV and has utility as a personal monitor. That is, when an LCD TV to which the digital adaptive brightness adjustment function according to the embodiment of the present invention is applied is used as a monitor, there is a very high possibility that problems will occur.

  For example, if you perform document work or web surfing on an LCD TV with a digital adaptive brightness adjustment function, it may cause excessive brightness and may cause eye fatigue. There is a problem that the brightness level of the LCD screen changes drastically.

  Thus, in order to remove eye fatigue and excessive luminance level change, it is necessary to arbitrarily turn on / off the digital adaptive luminance adjustment function through an external operation.

  Therefore, in another embodiment of the present invention, the characteristics of an externally input video signal are analyzed, and the input video is a video signal for TV, video player, DVD, etc., or on a monitor. A video identification method for identifying whether a stop video signal is used and automatically turning on / off a digital adaptive brightness adjustment function according to an embodiment of the present invention, and to realize the video identification method Provided are a liquid crystal display device and a driving device thereof.

  In general, a video signal for a TV or a video player is a medium in which an actual video is stored in a camera and is converted into an analog or digital signal to be transmitted or recorded. Therefore, even if a limited fixed portion for each frame of the video is converted into a digital or analog signal, a difference occurs in a minute portion between frames.

  In addition, the signal based on the stop video is generated on the basis of a digital device. If this is expressed on a digital signal processing medium such as an LCD monitor, the frame may be different unless the screen is artificially changed. The fine gradation part has the same value.

  FIG. 6 is a diagram for explaining a liquid crystal display device having an adaptive brightness adjustment function according to another embodiment of the present invention, and FIG. 7 is a diagram for explaining a unit cell set according to the present invention. is there.

  1 and 6, a liquid crystal display device having an adaptive brightness adjustment function according to another embodiment of the present invention includes a liquid crystal display module 100, a timing controller 200, a gate driver (or scan driver) 300, and a data driver. 400, the backlight power converter 500, and the gray voltage generator 600, which perform the same operation as in FIG. 1, are not shown and described.

  The timing control unit 200 disclosed in another embodiment of the present invention includes a data coefficient unit 210, a first summation unit 220, a second summation unit 230, a comparison unit 240, a video inquiry unit 270, and a brightness control unit 280. Components that perform the same operations as in FIG. 1 are given the same drawing numbers, and descriptions thereof are also omitted.

  The video inquiry unit 270 includes a frame coefficient unit 272, a storage unit 274, a data comparison unit 276, and a video discrimination unit 278, and checks whether the characteristics of the input video data is a moving video or a stop video. The video discrimination signal 271 that differs depending on the checked video is output.

  More specifically, the frame coefficient unit 272 extracts first data sets corresponding to a plurality of unit cells from the video data of the k-th frame input from the outside, and stores them first in the storage unit 274, and (k + N) When video data of the th frame is input, the second data set corresponding to a plurality of unit cells is extracted and stored in the storage unit 274, and then the first data set and the second data set are combined with the data comparison unit. 276.

  Here, as shown in FIG. 7, the plurality of unit cells are 3 * 3 pixel blocks including one pixel, and the first unit cell corresponds to the center of the screen of the video data to be displayed on the LCD panel. Point (E), second point (B) corresponding to the center of the upper end of the screen, third point (H) corresponding to the center of the lower end of the screen, and fourth point corresponding to the left side of the middle end of the screen (D) It is preferable that the 5th point (F) corresponding to the right side of a screen middle edge part is included.

  In addition, a sixth point (A) corresponding to the left side of the upper end of the screen, a seventh point (C) corresponding to the right side of the upper end of the screen, an eighth point (G) corresponding to the left side of the lower end of the screen, A ninth point (I) corresponding to the right side of the lower end of the screen may be further included.

  In FIG. 7, the pixel blocks are arranged at 1/6 or 1/2 with respect to the upper and lower ends, the left and right sides of the screen as an example. The gist of the present invention is not limited by numerical values.

  The storage unit 274 includes a memory or a register, and stores each video data corresponding to the unit cell from the frame coefficient unit 272.

  The data comparison unit 276 compares the first data set and the second data set from the frame coefficient unit 272 and provides the video discrimination unit 278 with the first signal or the second signal as a data comparison signal. For example, when the first data set and the second data set are the same when compared between video data corresponding to a specific cell, the first signal is set to “0” and output, and if different, Is set to '1' as the second signal and output. Here, the first signal and the second signal to be set have been described with “0” and “1” as an example, but “1” and “0” can also be set, and other values should be set. You can also.

  When “0” is input as the first signal from the data comparison unit 276, the image determination unit 278 determines that the image is a stop image, and outputs the first image determination signal to the luminance control unit 280, and the second signal. When “1” is input, the video is determined to be a moving video and a second video discrimination signal is output to the luminance control unit 280.

  The luminance control unit 280 includes a backlight luminance processing unit 282, a memory / gamma control unit 284, and a ROM 286, and backlight control corresponding to the backlight luminance signal based on the first video determination signal or the second video determination signal. Output signal and signal for gamma voltage control.

  In more detail, the backlight luminance processing unit 282 sends a first control signal unrelated to the backlight luminance signal to the power converter 500 when the first video determination signal is input from the video inquiry unit 270. When a second video discrimination signal is input from the video inquiry unit 270, a second control signal corresponding to the backlight luminance signal is output to the power converter 500.

  When the first control signal is input, the memory / gamma control unit 284 receives a gamma voltage from the ROM 286 that stores a corrected gamma voltage or a constant gamma voltage regardless of the backlight luminance signal. The voltage is extracted and output, and when the second control signal is input, the gamma voltage corrected based on the backlight luminance signal is output to the gamma processing unit 290.

  The gamma processing unit 290 includes a gamma voltage corrected based on the backlight luminance signal provided from the memory / gamma control unit 284, a gamma voltage corrected regardless of the backlight luminance signal, or a constant value of gamma. The voltage is received and provided to the data driver 400. Here, it has been described that the gamma processing unit 290 is configured separately from the timing control unit 200, but may be included in the timing control unit 200.

  As described in the other embodiments of the present invention, the characteristics of video data input from the outside are examined, and when it is determined that the video is a stop video, the liquid crystal display device can be used as a monitor. it can. That is, by stopping the brightness enhancement function according to the embodiment of the present invention and always providing a constant brightness signal based on an external reference signal or a constant brightness signal set to itself, a stable screen is output. Thus, power consumption can be saved and the contrast of the screen can be maintained.

  In addition, when the characteristics of the input video data are determined to be moving images, the liquid crystal display device can be used as a TV, a video player, a DVD, or the like. The increase function can be activated to output high luminance by the luminance increase signal, and the contrast of the screen can be maintained.

  At this time, one method for checking whether the video data is a stop video or a moving video is divided into a plurality of unit cells in one frame and displayed by comparing data signals for each frame at regular intervals. Checking whether the screen is a stop image or a moving image.

  Hereinafter, a method for checking whether an input image is a moving image or a stop image will be described in detail with reference to the accompanying drawings.

  8A to 8B are flowcharts for explaining a driving method of a liquid crystal display device having an adaptive brightness adjustment function according to another embodiment of the present invention.

  8A and 8B, first, as shown in FIG. 7, a plurality of unit cells displayed in one frame are set (step S610).

  Next, the first data set obtained by extracting the video data corresponding to the unit cell from the currently input frame is stored (step S615). The first data set stored at this time can be data corresponding to 9 points, or data corresponding to 5 points corresponding to each point of the cross pattern.

  Next, it is checked whether or not N frames have passed (step S620). If N frames have passed, a second data set obtained by extracting video data corresponding to the unit cell from the input frames is stored. The first data set and the second data set that have already been stored are compared, and the first comparison data is stored (step S625).

  Next, it is checked whether or not the first data set is the same as the second data set (step S630), and if it is checked that it is the same, it is set to '0' as the first comparison data ( In step S632), when it is checked that they are different, the first comparison data is set to '1' (step S634).

  Next, it is checked whether or not the output value of the horizontal direction comparison data, for example, all three points are “1” (step S640), and even if there is one output value of the horizontal direction comparison data, it is not “1”. In step S645, it is checked whether four or more of the comparison data are “1”. Here, checking the output value of the horizontal direction comparison data has been described as an example, but it is also possible to check the output value of the vertical direction comparison data.

  If four or more of the comparison data is '1' in step S645, it is determined as a moving image (step S650), and if four or more are not '1', it is determined as a stop image (step S652). If all the output values of the horizontal or vertical comparison data are “1” in S640, it is determined as a moving image (step S654).

  After steps S650, S652, and S654, it is checked whether M (where M is a positive integer larger than N) frames have passed (step S660). If M frames have passed, input is performed. The third data set obtained by extracting the video data corresponding to the unit cell from the frame to be stored is stored, the second data set is compared with the third data set, and the second comparison data is stored (step S665).

  Next, it is checked whether or not the second comparison data is “1” and the setting screen satisfies a first condition that is a moving image (step S670). If the first condition is satisfied, the step S670 is performed. It is checked whether or not is performed twice (step S675). If it is checked in step S675 that the step S670 has been performed twice, the process is fed back to step S615. If it is checked that the process has not been performed twice, the process is fed back to step S660. Here, the case where the step S670 is performed twice when the first condition is satisfied has been described as an example, but the case where the step S670 is performed three times or more may be exemplified.

  If the second comparison data is not “1” and the setting screen is not a moving image in step S670, the second comparison data is “0” and the setting screen is a stop image. It is checked whether the condition is satisfied (step S680). If the second condition is satisfied, it is checked whether the step S680 is performed twice (step S685). If it is checked in step S685 that the step S680 has been performed twice, the process returns to step S615. If it is checked that the process has not been performed twice, the process returns to step S660.

  Although the foregoing has been described with reference to preferred embodiments of the invention, those skilled in the art will recognize that the invention is within the scope and spirit of the invention as defined by the appended claims. It will be understood that various modifications and changes can be made.

  As described above, according to the embodiment of the present invention, the grayscale voltage level of the RGB video data forming one frame is checked in the liquid crystal display device. When it is determined that the luminance level is high according to the number of checked gradation voltage levels, the backlight luminance is controlled to be higher than the general level, and when it is determined that the luminance level is low, the general level is set. Maintain the backlight brightness. At the same time, by performing gradation conversion of low gradation data, higher contrast can be realized.

  In other words, if the screen concentrates on high gradation locally (or a screen that requires high contrast) or the screen has many high gradations overall (or a screen that requires high brightness), the back If the brightness of the light is increased, and otherwise, the brightness is kept normal, the contrast of the liquid crystal display device can be increased or the dynamic range can be increased.

  According to another embodiment of the present invention, a plurality of specific portions of the display screen are selected, and the characteristics of the displayed image are defined by tracking and observing changes in the image data. The digital AI according to the embodiment of the present invention, that is, whether the video data is a moving image or a still image and whether or not to use a backlight control function is determined, and the luminance level of the backlight is controlled. can do.

  Further, according to another embodiment of the present invention, it is possible to determine whether or not the digital AI is applicable, and thereby to control the output of the corrected gamma voltage level. By controlling the brightness level of the backlight and the output control of the corrected gamma voltage level, the contrast of the display screen can be adjusted, and the power consumption when the corresponding liquid crystal display device displays a stop video, etc. Can be saved.

The figure for demonstrating the liquid crystal display device by one Example of this invention. Diagram for explaining general number of data by gradation 6 is a flowchart for explaining a liquid crystal display method according to an embodiment of the present invention. The figure for demonstrating the brightness | luminance classified by gradation before tuning by this invention, and the brightness | luminance classified by gradation after tuning The figure which showed the gradation tuning which considered the luminance change of the backlight by this invention FIG. 6 is a diagram for explaining a liquid crystal display device according to another embodiment of the present invention. The figure for demonstrating the unit cell set by this invention 7 is a flowchart for explaining a driving method of a liquid crystal display device according to another embodiment of the present invention. 7 is a flowchart for explaining a driving method of a liquid crystal display device according to another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Liquid crystal display module 110 LCD panel 120 Backlight part 200 Timing control part 210 Data coefficient part 212 R Data coefficient part 212-1 Data discrimination | determination part 212-3 1st counter 212-5 2nd counter 212-7 1st adder 212 -9 2nd adder 214 G data coefficient part 216 B data coefficient part 220 1st summation part 230 2nd summation part 240 Comparison part 241 Luminance control signal 250 Memory control part 251 Gradation conversion control signal 255, 286 ROM
260 SRAM portion 262 First SRAM
H.264 second SRAM
266 Third SRAM
270 Video inquiry unit 271 Video discrimination signal 272 Frame coefficient unit 274 Storage unit 276 Data comparison unit 278 Video discrimination unit 280 Brightness control unit 282 Backlight brightness processing unit 284 Memory / gamma control unit 290 Gamma processing unit 300 Gate driver 400 Data driver 500 Backlight inverter (power converter)
600 gradation voltage generator

Claims (9)

LCD panel,
A backlight unit that illuminates the LCD panel with a luminance according to a backlight driving voltage;
A gate driver that outputs a scanning signal to the LCD panel;
A data driver for outputting an image signal to the LCD panel;
A power converter that outputs a backlight driving voltage to the backlight unit; and
In response to an externally input video signal and timing signal, the gate driver outputs a signal for outputting a scanning signal, the data driver outputs a signal for outputting an image signal, and A timing control unit that outputs a backlight control signal for instructing the level of the backlight drive voltage to the power converter;
A liquid crystal display device having
The timing controller is
The characteristics of the video signal are checked to determine whether the video type indicated by the video signal is a moving video or a stop video. If the determined video type is a stop video, the first type is determined. A video inquiry unit that outputs a video discrimination signal, and outputs a second video discrimination signal when the type of the discriminated video is a moving video; and
When the first video discrimination signal is input, a backlight control signal for instructing the level of the backlight driving voltage maintained constant is output, and when the second video discrimination signal is input, A luminance control unit that outputs a backlight control signal for instructing a level of a backlight driving voltage that is adjusted according to the level of luminance required by the video signal;
Including
The video inquiry unit
A storage unit for storing the video signal;
A first data set corresponding to each of a plurality of unit cells included in the screen of the LCD panel is extracted from the kth frame of the video signal and stored in the storage unit, and from the (k + N) th frame. Extracts a second data set corresponding to each of the plurality of unit cells, stores the second data set in the storage unit, and outputs the first data set and the second data set from the storage unit;
A data comparison unit that compares the first data set and the second data set corresponding to the same unit cell, and outputs a first signal if they are equal, and outputs a second signal if they are different; as well as,
The first video according to the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. A video discriminating section for outputting either the discrimination signal or the second video discrimination signal;
Including
The video discriminating unit includes the data comparison unit indicating a comparison result between the first data set and the second data set corresponding to each of the unit cells arranged in the first direction among the plurality of unit cells. It is checked whether all the signals are the second signals, and if all the checked signals are the second signals, a second video discrimination signal is output, and any one of the checked signals is the first signal. If it is not two signals, it is checked whether or not the number of second signals included in the series of signals from the data comparison unit is equal to or greater than a predetermined number, and the number of second signals is equal to or greater than the predetermined number. A second video discrimination signal is output when the number is less than the predetermined number, and a first video discrimination signal is output when the number is less than the predetermined number,
Liquid crystal display device. LCD panel and
A backlight unit that illuminates the LCD panel with a luminance according to a backlight driving voltage;
An apparatus for driving a liquid crystal display device having
A gate driver that outputs a scanning signal to the LCD panel;
A data driver for outputting an image signal to the LCD panel;
A power converter that outputs a backlight driving voltage to the backlight unit; and
In response to an externally input video signal and timing signal, the gate driver outputs a signal for outputting a scanning signal, the data driver outputs a signal for outputting an image signal, and A timing control unit that outputs a backlight control signal for instructing the level of the backlight drive voltage to the power converter;
Have
The timing controller is
The characteristics of the video signal are checked to determine whether the video type indicated by the video signal is a moving video or a stop video. If the determined video type is a stop video, the first type is determined. A video inquiry unit that outputs a video discrimination signal, and outputs a second video discrimination signal when the type of the discriminated video is a moving video; and
When the first video discrimination signal is input, a backlight control signal for instructing the level of the backlight driving voltage maintained constant is output, and when the second video discrimination signal is input, A luminance control unit that outputs a backlight control signal for instructing a level of a backlight driving voltage that is adjusted according to the level of luminance required by the video signal;
Including
The video inquiry unit
A storage unit for storing the video signal;
A first data set corresponding to each of a plurality of unit cells included in the screen of the LCD panel is extracted from the kth frame of the video signal and stored in the storage unit, and from the (k + N) th frame. Extracts a second data set corresponding to each of the plurality of unit cells, stores the second data set in the storage unit, and outputs the first data set and the second data set from the storage unit;
A data comparison unit that compares the first data set and the second data set corresponding to the same unit cell, and outputs a first signal if they are equal, and outputs a second signal if they are different; as well as,
The first video according to the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. A video discriminating section for outputting either the discrimination signal or the second video discrimination signal;
Including
The video discriminating unit includes the data comparison unit indicating a comparison result between the first data set and the second data set corresponding to each of the unit cells arranged in the first direction among the plurality of unit cells. It is checked whether all the signals are the second signals, and if all the checked signals are the second signals, a second video discrimination signal is output, and any one of the checked signals is the first signal. If it is not two signals, it is checked whether or not the number of second signals included in the series of signals from the data comparison unit is equal to or greater than a predetermined number, and the number of second signals is equal to or greater than the predetermined number. A second video discrimination signal is output when the number is less than the predetermined number, and a first video discrimination signal is output when the number is less than the predetermined number,
Driving device for liquid crystal display device. A method for driving a liquid crystal display device including an LCD panel and a backlight unit that illuminates the LCD panel,
Selecting a plurality of unit cells from the screen of the LCD panel;
Extracting and storing a first data set corresponding to each of the plurality of unit cells from a k-th frame of a video signal input to the liquid crystal display device from the outside;
Extracting and storing a second data set corresponding to each of the plurality of unit cells from the (k + N) th frame of the video signal;
The first data set and the second data set corresponding to the same unit cell are compared, and if they are equal, the first value is set as the first comparison value, and if they are different, the second value is set. Setting as a first comparison value,
Checking whether the first comparison value is the second value for all of the unit cells arranged in the first direction among the plurality of unit cells;
Determining that the type of video indicated by the video signal is a moving video when the first comparison value is a second value for all of the unit cells arranged in the first direction;
If the first comparison value is not the second value for any of the unit cells arranged in the first direction, the first comparison value that is the second value among the first comparison values for all of the plurality of unit cells. Checking whether the number of is greater than or equal to a predetermined number,
When the number of the first comparison values is equal to or greater than the predetermined number, it is determined that the video type indicated by the video signal is a moving image, and the number of the first comparison values is less than the predetermined number The step of determining that the type of video indicated by the video signal is a stop video,
When it is determined that the video type indicated by the video signal is a moving video, the LCD panel controls the luminance of the backlight unit in units of one frame according to the luminance level required by the video signal. Displaying video on the screen, and
When it is determined that the video type indicated by the video signal is a stop video, displaying the video on the LCD panel while maintaining the brightness of the backlight unit constant;
A method for driving a liquid crystal display device, comprising: LCD panel,
A backlight unit that illuminates the LCD panel with a luminance according to a backlight driving voltage;
A gate driver that outputs a scanning signal to the LCD panel;
A data driver for outputting an image signal to the LCD panel;
A power converter that outputs a backlight driving voltage to the backlight unit; and
In response to an externally input video signal and timing signal, the gate driver outputs a signal for outputting a scanning signal, the data driver outputs a signal for outputting an image signal, and A timing control unit that outputs a backlight control signal for instructing the level of the backlight drive voltage to the power converter;
A liquid crystal display device having
The timing controller is
The characteristics of the video signal are checked to determine whether the video type indicated by the video signal is a moving video or a stop video. If the determined video type is a stop video, the first type is determined. A video inquiry unit that outputs a video discrimination signal, and outputs a second video discrimination signal when the type of the discriminated video is a moving video; and
When the first video discrimination signal is input, the first backlight control signal for instructing the level of the backlight drive voltage maintained constant is output, and when the second video discrimination signal is input. A luminance control unit that outputs a second backlight control signal for indicating a level of a backlight driving voltage that is adjusted according to the level of luminance required by the video signal;
Including
The video inquiry unit
A storage unit for storing the video signal;
A first data set corresponding to each of a plurality of unit cells is extracted from the kth frame of the video signal and stored in the storage unit, and from the (k + N) th frame to each of the plurality of unit cells. A corresponding second data set is extracted and stored in the storage unit, and a frame coefficient unit that outputs the first data set and the second data set from the storage unit;
A data comparison unit that compares the first data set and the second data set corresponding to the same unit cell, and outputs a first signal if they are equal, and outputs a second signal if they are different; as well as,
The first video according to the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. A video discriminating section for outputting either the discrimination signal or the second video discrimination signal;
Including
The video discriminating unit checks whether or not the series of signals are all second signals, and if the checked signals are all second signals, outputs a second video discriminating signal. If any of the received signals is not the second signal, it is checked whether or not the number of the second signals included in the series of signals is equal to or greater than a predetermined number, and the number of the second signals is When the number is equal to or greater than the predetermined number, a second video determination signal is output. When the number is less than the predetermined number, the first video determination signal is output.
The timing control unit divides gradation data included in one frame of the video signal into at least three groups according to the gradation level, and the first group having the highest gradation level and the lowest gradation level. The gradation data is counted for each of the second groups, and the number of gradation data included in the first group is equal to or greater than the first ratio with respect to the total number of gradation data included in one frame of the video signal. And the number of gradation data included in the second group is equal to or greater than the second ratio with respect to the total number, the level of the backlight driving voltage indicated by the second backlight control signal is set. The gradation level indicated by the gradation data having a low gradation level among the gradation data included in the video signal is converted to be lower than the normal one.
Liquid crystal display device. LCD panel and
A backlight unit that illuminates the LCD panel with a luminance according to a backlight driving voltage;
An apparatus for driving a liquid crystal display device having
A gate driver that outputs a scanning signal to the LCD panel;
A data driver for outputting an image signal to the LCD panel;
A power converter that outputs a backlight driving voltage to the backlight unit; and
In response to an externally input video signal and timing signal, the gate driver outputs a signal for outputting a scanning signal, the data driver outputs a signal for outputting an image signal, and A timing control unit that outputs a backlight control signal for instructing the level of the backlight drive voltage to the power converter;
Have
The timing controller is
The characteristics of the video signal are checked to determine whether the video type indicated by the video signal is a moving video or a stop video. If the determined video type is a stop video, the first type is determined. A video inquiry unit that outputs a video discrimination signal, and outputs a second video discrimination signal when the type of the discriminated video is a moving video; and
When the first video discrimination signal is input, the first backlight control signal for instructing the level of the backlight drive voltage maintained constant is output, and when the second video discrimination signal is input. A luminance control unit that outputs a second backlight control signal for indicating a level of a backlight driving voltage that is adjusted according to the level of luminance required by the video signal;
Including
The video inquiry unit
A storage unit for storing the video signal;
A first data set corresponding to each of a plurality of unit cells is extracted from the kth frame of the video signal and stored in the storage unit, and from the (k + N) th frame to each of the plurality of unit cells. A corresponding second data set is extracted and stored in the storage unit, and a frame coefficient unit that outputs the first data set and the second data set from the storage unit;
A data comparison unit that compares the first data set and the second data set corresponding to the same unit cell, and outputs a first signal if they are equal, and outputs a second signal if they are different; as well as,
The first video according to the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. A video discriminating section for outputting either the discrimination signal or the second video discrimination signal;
Including
The video discriminating unit checks whether or not the series of signals are all second signals, and if the checked signals are all second signals, outputs a second video discriminating signal. If any of the received signals is not the second signal, it is checked whether or not the number of the second signals included in the series of signals is equal to or greater than a predetermined number, and the number of the second signals is When the number is equal to or greater than the predetermined number, a second video determination signal is output. When the number is less than the predetermined number, the first video determination signal is output.
The timing control unit divides gradation data included in one frame of the video signal into at least three groups according to the gradation level, and the first group having the highest gradation level and the lowest gradation level. The gradation data is counted for each of the second groups, and the number of gradation data included in the first group is equal to or greater than the first ratio with respect to the total number of gradation data included in one frame of the video signal. And the number of gradation data included in the second group is equal to or greater than the second ratio with respect to the total number, the level of the backlight driving voltage indicated by the second backlight control signal is set. The gradation level indicated by the gradation data having a low gradation level among the gradation data included in the video signal is converted to be lower than the normal one.
Driving device for liquid crystal display device. A method for driving a liquid crystal display device including an LCD panel and a backlight unit that illuminates the LCD panel,
(A) selecting a plurality of unit cells from the screen of the LCD panel;
(B) extracting and storing a first data set corresponding to each of the plurality of unit cells from a k-th frame of a video signal input to the liquid crystal display device from the outside;
(C) extracting and storing a second data set corresponding to each of the plurality of unit cells from the (k + N) th frame of the video signal;
(D) The first data set and the second data set corresponding to the same unit cell are compared, and if both are equal, the first value is set as the first comparison value; Setting the value of as a first comparison value,
(E) determining that the type of video indicated by the video signal is a moving video when the first comparison value is the second value for all of the plurality of unit cells;
(F) if the first comparison value is not the second value for any of the plurality of unit cells, the step of checking whether the number of the first comparison values as the second value is equal to or greater than a predetermined number;
(G) When the number of the first comparison values is equal to or greater than the predetermined number, it is determined that the video type indicated by the video signal is a moving image, and the number of the first comparison values is less than the predetermined number. If it is, the step of determining that the video type indicated by the video signal is a stop video,
(H) When it is determined that the type of video indicated by the video signal is a moving video, while controlling the luminance of the backlight unit in units of one frame according to the level of luminance required by the video signal, Displaying an image on the LCD panel; and
(I) when it is determined that the video type indicated by the video signal is a stop video, displaying the video on the LCD panel while controlling the brightness of the backlight unit to be constant;
Including
Stage (h)
(H-1) The gradation data included in one frame of the video signal is divided into at least three groups according to the gradation level, and the first group having the highest gradation level and the first having the lowest gradation level. Counting gradation data for each of the two groups;
(H-2) Checking whether the number of gradation data included in the first group is equal to or greater than a first ratio with respect to the total number of gradation data included in one frame of the video signal. ,
(H-3) When the number of gradation data included in the first group is equal to or greater than the first ratio with respect to the total number, the number of gradation data included in the second group is the total number. Checking whether it is greater than or equal to the second ratio, and
(H-4) When the number of gradation data included in the second group is equal to or greater than the second ratio with respect to the total number, the luminance of the backlight unit is set higher than a normal level, and the gradation level Converting the gradation level indicated by the low gradation data to a lower level,
A method for driving a liquid crystal display device, comprising: LCD panel,
A backlight unit that illuminates the LCD panel with a luminance according to a backlight driving voltage;
A gate driver that outputs a scanning signal to the LCD panel;
A data driver for outputting an image signal to the LCD panel;
A power converter that outputs a backlight driving voltage to the backlight unit; and
In response to an externally input video signal and timing signal, the gate driver outputs a signal for outputting a scanning signal, the data driver outputs a signal for outputting an image signal, and A timing control unit that outputs a backlight control signal for instructing the level of the backlight drive voltage to the power converter;
A liquid crystal display device having
The timing controller is
The characteristics of the video signal are checked to determine whether the video type indicated by the video signal is a moving video or a stop video. If the determined video type is a stop video, the first type is determined. A video inquiry unit that outputs a video discrimination signal, and outputs a second video discrimination signal when the type of the discriminated video is a moving video; and
When the first video discrimination signal is input, a backlight control signal for instructing the level of the backlight driving voltage maintained constant is output, and when the second video discrimination signal is input, A luminance control unit that outputs a backlight control signal for instructing a level of a backlight driving voltage that is adjusted according to the level of luminance required by the video signal;
Including
The video inquiry unit
A storage unit for storing the video signal;
A first data set corresponding to each of a plurality of unit cells included in the screen of the LCD panel is extracted from the kth frame of the video signal and stored in the storage unit, and from the (k + N) th frame. Extracts a second data set corresponding to each of the plurality of unit cells and stores the second data set in the storage unit. From the (k + N + M) th frame, the unit cells arranged in the first direction among the plurality of unit cells. A third coefficient set corresponding to each extracted and stored in the storage unit, a frame coefficient unit for outputting the first data set, the second data set, and the third data set from the storage unit;
Compare the first data set and the second data set corresponding to the same unit cell, or compare the second data set and the third data set corresponding to the same unit cell, and both are equal. A data comparison unit that outputs a first signal in the case and a second signal in the case of different, and
The first video according to the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. The data comparison unit that outputs either a discrimination signal or a second video discrimination signal and indicates a comparison result between the second data set and the third data set for each of the unit cells arranged in the first direction. Depending on whether each of the signals from the first signal or the second signal is in the frame coefficient portion, at least one of the first data set, the second data set, and the third data set A video discriminating unit for extracting again,
Including
Whether the video discriminating unit is the second signal for all the series of signals from the data comparing unit indicating the comparison result between the first data set and the second data set for all of the plurality of unit cells. If all the checked signals are second signals, a second video discrimination signal is output. If any of the checked signals is not a second signal, the series of signals are output. Whether the number of second signals included in the signal is equal to or greater than a predetermined number, and if the number of the second signals is equal to or greater than the predetermined number, a second video discrimination signal is output, If the number is less than the predetermined number, the first video discrimination signal is output,
The video discriminating unit is configured such that a series of signals from the data comparing unit indicating the comparison results between the second data set and the third data set for all the unit cells arranged in the first direction are all second signals. If the video signal has already been determined to be a moving image, the third data set is repeated in the frame coefficient section every time the video signal advances M frames. A series of signals from the data comparison unit indicating the comparison results between the second data set and the third data set for all of the unit cells arranged in the first direction are extracted at least twice. If it is repeated as a signal, the frame coefficient unit again extracts all of the first data set, the second data set, and the third data set,
In the video discriminating unit, a signal from the data comparing unit indicating a comparison result between the second data set and the third data set for any of the unit cells arranged in the first direction is not the second signal. In this case, among the unit cells arranged in the first direction, the signal from the data comparison unit indicating the comparison result between the second data set and the third data set for the unit cell at the intermediate point is the first signal. And if it is already determined that the video type indicated by the video signal is a stop video, the frame coefficient portion repeatedly extracts the third data set every time the video signal advances M frames, At least twice, the signal from the data comparison unit indicating the comparison result between the second data set and the third data set for the unit cell at the intermediate point is the first signal. After the loop is possible, the Frame coefficient unit, the first data set, the second data set, and all is extracted again the third data set,
Liquid crystal display device. LCD panel and
A backlight unit that illuminates the LCD panel with a luminance according to a backlight driving voltage;
An apparatus for driving a liquid crystal display device having
A gate driver that outputs a scanning signal to the LCD panel;
A data driver for outputting an image signal to the LCD panel;
A power converter that outputs a backlight driving voltage to the backlight unit; and
In response to an externally input video signal and timing signal, the gate driver outputs a signal for outputting a scanning signal, the data driver outputs a signal for outputting an image signal, and A timing control unit that outputs a backlight control signal for instructing the level of the backlight drive voltage to the power converter;
Have
The timing controller is
The characteristics of the video signal are checked to determine whether the video type indicated by the video signal is a moving video or a stop video. If the determined video type is a stop video, the first type is determined. A video inquiry unit that outputs a video discrimination signal, and outputs a second video discrimination signal when the type of the discriminated video is a moving video; and
When the first video discrimination signal is input, a backlight control signal for instructing the level of the backlight driving voltage maintained constant is output, and when the second video discrimination signal is input, A luminance control unit that outputs a backlight control signal for instructing a level of a backlight driving voltage that is adjusted according to the level of luminance required by the video signal;
Including
The video inquiry unit
A storage unit for storing the video signal;
A first data set corresponding to each of a plurality of unit cells included in the screen of the LCD panel is extracted from the kth frame of the video signal and stored in the storage unit, and from the (k + N) th frame. Extracts a second data set corresponding to each of the plurality of unit cells and stores the second data set in the storage unit. From the (k + N + M) th frame, the unit cells arranged in the first direction among the plurality of unit cells. A third coefficient set corresponding to each extracted and stored in the storage unit, a frame coefficient unit for outputting the first data set, the second data set, and the third data set from the storage unit;
Compare the first data set and the second data set corresponding to the same unit cell, or compare the second data set and the third data set corresponding to the same unit cell, and both are equal. A data comparison unit that outputs a first signal in the case and a second signal in the case of different, and
The first video according to the number of second signals included in a series of signals from the data comparison unit indicating a comparison result between the first data set and the second data set for all of the plurality of unit cells. The data comparison unit that outputs either a discrimination signal or a second video discrimination signal and indicates a comparison result between the second data set and the third data set for each of the unit cells arranged in the first direction. Depending on whether each of the signals from the first signal or the second signal is in the frame coefficient portion, at least one of the first data set, the second data set, and the third data set A video discriminating unit for extracting again,
Including
Whether the video discriminating unit is the second signal for all the series of signals from the data comparing unit indicating the comparison result between the first data set and the second data set for all of the plurality of unit cells. If all the checked signals are second signals, a second video discrimination signal is output. If any of the checked signals is not a second signal, the series of signals are output. Whether the number of second signals included in the signal is equal to or greater than a predetermined number, and if the number of the second signals is equal to or greater than the predetermined number, a second video discrimination signal is output, If the number is less than the predetermined number, the first video discrimination signal is output,
In the video discriminating unit, all signals from the data comparing unit indicating comparison results between the second data set and the third data set for all the unit cells arranged in the first direction are all second signals. And, if it is already determined that the video type indicated by the video signal is a moving video, the frame coefficient unit repeatedly extracts the third data set every time the video signal advances M frames. The signals from the data comparison unit indicating the comparison results between the second data set and the third data set for all the unit cells arranged in the first direction at least twice are all second signals. If the above is repeated, the frame coefficient unit is allowed to extract all of the first data set, the second data set, and the third data set again,
In the video discriminating unit, a signal from the data comparing unit indicating a comparison result between the second data set and the third data set for any of the unit cells arranged in the first direction is not the second signal. In this case, among the unit cells arranged in the first direction, the signal from the data comparison unit indicating the comparison result between the second data set and the third data set for the unit cell at the intermediate point is the first signal. And if it is already determined that the video type indicated by the video signal is a stop video, the frame coefficient portion repeatedly extracts the third data set every time the video signal advances M frames, At least twice, the signal from the data comparison unit indicating the comparison result between the second data set and the third data set for the unit cell at the intermediate point is the first signal. After the loop is possible, the Frame coefficient unit, the first data set, the second data set, and all is extracted again the third data set,
Driving device for liquid crystal display device. A method for driving a liquid crystal display device including an LCD panel and a backlight unit that illuminates the LCD panel,
(A) selecting a plurality of unit cells from the screen of the LCD panel;
(B) extracting and storing a first data set corresponding to each of the plurality of unit cells from a k-th frame of a video signal input to the liquid crystal display device from the outside;
(C) extracting and storing a second data set corresponding to each of the plurality of unit cells from the (k + N) th frame of the video signal;
(D) The first data set and the second data set corresponding to the same unit cell are compared, and if both are equal, the first value is set as the first comparison value; Setting the value of as a first comparison value,
(E) determining that the type of video indicated by the video signal is a moving video when the first comparison value is the second value for all of the plurality of unit cells;
(F) if the first comparison value is not the second value for any of the plurality of unit cells, the step of checking whether the number of the first comparison values as the second value is equal to or greater than a predetermined number;
(G) When the number of the first comparison values is equal to or greater than the predetermined number, it is determined that the video type indicated by the video signal is a moving image, and the number of the first comparison values is less than the predetermined number. If it is, the step of determining that the video type indicated by the video signal is a stop video,
(H) When it is determined that the type of video indicated by the video signal is a moving video, while controlling the luminance of the backlight unit in units of one frame according to the level of luminance required by the video signal, Displaying an image on the LCD panel;
(I) when it is determined that the video type indicated by the video signal is a stop video, displaying the video on the LCD panel while controlling the brightness of the backlight unit to be constant;
(J) A third data set corresponding to each of the unit cells arranged in the first direction is extracted from the (k + N + M) th frame of the video signal to correspond to the same unit cell. Comparing with the second data set, if both are equal, setting the first value as the second comparison value; otherwise, setting the second value as the second comparison value;
(K) When the second comparison value is the second value for all the unit cells arranged in the first direction, and the video type indicated by the video signal has already been determined to be a moving video. While maintaining the determination, the video signal is further advanced by M frames and the step (j) is repeated, and the second comparison value is the second value for all the unit cells arranged in the first direction at least twice. If this is repeated, the process returns to the step (b) from the next frame of the video signal;
(L) If the second comparison value is not the second value for any of the unit cells arranged in the first direction, the second comparison value for the unit cell at the middle point among the unit cells arranged in the first direction is If it is determined that the video type indicated by the video signal is a stop video, the video signal is further advanced by M frames while maintaining the determination, and the step (j) is performed. Repeatedly, if it is repeated at least twice that the second comparison value for the unit cell at the intermediate point is the first value, the process returns to the step (b) from the next frame of the video signal; as well as,
(M) Of the unit cells arranged in the first direction, the second comparison value is the second value for the unit cell at the intermediate point, but the second comparison value is the second value for any other unit cell. If the value is not 2, the process returns to the step (b) from the next frame of the video signal;
A method for driving a liquid crystal display device, comprising:

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