KR20080094261A - Lcd and drive method thereof - Google Patents

Abstract

An LCD(Liquid Crystal Display) and a driving method thereof are provided to prevent flickers due to a brightness difference between frames by increasing a brightness of the frame according to brightness values of respective pixels of an input frame. An LCD includes a frame processor(120), a timing controller(130), and a data driver(140). The frame processor multiplies a frame frequency of an input frame and generates multiplied odd-numbered and even-numbered frames. The frame processor increases or decreases brightness values of the odd-numbered and even-numbered frames by using low gradation conversion values and high gradation conversion values according to an APL(Average Picture Level) of the pixels of the input frame. The timing controller controls driving timings of the odd-numbered and even-numbered frames having the converted gradation values from the frame processor. The data driver continuously drives an LCD panel during the multiplied odd-numbered and even-numbered frames under the control of the timing controller.

Description

Liquid crystal display and driving method thereof

1 is an equivalent circuit diagram of each pixel formed in a general liquid crystal display device.

2 is a block diagram of a liquid crystal display device according to an exemplary embodiment of the present invention.

3 is a block diagram of the frame processor shown in FIG.

4 is a gamma curve curve set in the lookup table of FIG. 3.

Explanation of symbols on the main parts of the drawings

100: liquid crystal display device 110: liquid crystal display panel

120: frame handler 121: memory

122: frequency conversion controller 123: luminance value calculator

124: comparator 125: signal generator

126: Lookup Table 127: Gradation Converter

130: timing controller 140: data driver

150: gate driver 160: gamma reference voltage generator

170: backlight assembly 180: inverter

190: common voltage generator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a driving method thereof capable of increasing or decreasing a luminance value of a frame to which a frame frequency is assigned according to a luminance value of each pixel of an input frame.

A liquid crystal display device displays an image by adjusting light transmittance of liquid crystal cells according to a video signal, and an active matrix type liquid crystal display device in which a switching element is formed for each liquid crystal cell enables active control of the switching element. This is advantageous for video implementation. As the switching element used in the active matrix liquid crystal display device, a thin film transistor (hereinafter referred to as TFT) is mainly used as shown in FIG. 1.

Referring to FIG. 1, an active matrix type liquid crystal display converts digital input data into an analog data voltage based on a gamma reference voltage and supplies it to the data line DL and simultaneously supplies scan pulses to the gate line GL. The liquid crystal cell Clc is charged.

The gate electrode of the TFT is connected to the gate line GL, the source electrode is connected to the data line DL, and the drain electrode of the TFT is a pixel electrode of the liquid crystal cell Clc and one electrode of the storage capacitor Cst. Is connected to.

The common voltage Vcom is supplied to the common electrode of the liquid crystal cell Clc.

The storage capacitor Cst charges a data voltage applied from the data line DL when the TFT is turned on, thereby maintaining a constant voltage of the liquid crystal cell Clc.

When the scan pulse is applied to the gate line GL, the TFT is turned on to form a channel between the source electrode and the drain electrode so that the voltage on the data line DL is applied to the pixel electrode of the liquid crystal cell Clc. Supply. At this time, the liquid crystal molecules of the liquid crystal cell Clc modulate the incident light by changing the arrangement by the electric field between the pixel electrode and the common electrode.

A general liquid crystal display having pixels having a circuit structure as described above is driven at 60 Hz but has a problem that motion blur occurs due to a low frame frequency. The technique of double speed of the frame frequency to drive the 120Hz.

In the description of the frame frequency double speed technology, two frames are continuously driven within a predetermined time by using one frame input from the system, and one frame among the generated frames is displayed brightly and the other Darken the frame.

In the conventional liquid crystal display device having such a frame frequency double speed technology, the flicker due to the luminance difference between the frames is generated by converting the entire brightness of the doubled odd frame and the entire brightness of the even-numbered frame to a stepped wave form. Have a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device and a driving device capable of increasing or decreasing a luminance value of a frame to which a frame frequency is assigned according to the luminance value of each pixel of an input frame. To provide a way.

Another object of the present invention is to increase or decrease the luminance value of a frame to which the frame frequency is doubled according to the luminance value of each pixel of the input frame, thereby preventing flicker caused by the luminance difference between the frames during double-speed driving of the frame frequency. There is provided a liquid crystal display and a driving method thereof.

In order to achieve the above object, the liquid crystal display device of the present invention doubles the frame frequency of an input frame to generate an odd-numbered frame and even-numbered frame, and according to an average luminance value of pixels of the input frame. A frame processor for increasing and decreasing luminance values of the assigned odd-numbered frame and even-numbered frame by using low gray scale conversion values and predetermined high gray scale conversion values; A timing controller controlling driving timing of the assigned odd-numbered frame and the even-numbered frame having the gray scale value converted by the frame processor; And a data driver which drives the assigned odd-numbered frame and even-numbered frame to the liquid crystal display panel continuously within a predetermined time period under the control of the timing controller.

The frame processor may include a memory for temporarily storing the input frame; The frame notification signal '1' and the assigned even-numbered frame for displaying the assigned odd-numbered frame in succession while simultaneously outputting the assigned odd-numbered frame and even-numbered frame by speeding the frame frequency of the input frame stored in the memory. A frequency conversion controller for sequentially outputting a frame notification signal '0' indicating a frame; A luminance value calculator configured to calculate an average luminance value of the pixels of the input frame; The luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value is output by comparing the luminance value of each pixel of the assigned odd-numbered frame with the calculated average luminance value, and the assigned excellent value A comparator for comparing the luminance value of each pixel of the first frame with the magnitude of the calculated average luminance value and outputting a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value; A signal generator for generating a gradation conversion control signal '0' or '1' using the luminance difference notification signal and the frame notification signal; Store predetermined low gray level conversion values and the predetermined high gray level conversion values, which are selectively used for gray level conversion of each of the assigned odd-numbered frame and even-numbered frame, and according to the gray level conversion control signal; A look-up table for selectively outputting low gray scale conversion values and high gray scale conversion values; And a gray level value of each pixel of the odd-numbered frame and the even-numbered frame using the predetermined low gray level conversion values or the predetermined high gray level conversion values selectively output from the lookup table according to the gray level conversion control signal. It includes a gradation conversion unit for converting.

A driving method of a liquid crystal display of the present invention includes the steps of: generating a radix-numbered frame and even-numbered frame by speeding a frame frequency of an input frame; Increasing or decreasing luminance values of the assigned odd-numbered frame and even-numbered frame using predetermined low gray level conversion values and predetermined high gray level conversion values according to average luminance values of pixels of the input frame; And continuously driving the assigned odd-numbered frame and the even-numbered frame having the increased and decreased luminance value to the liquid crystal display panel within a predetermined time.

A driving method of a liquid crystal display of the present invention includes the steps of temporarily storing an input frame; The frame notification signal '1' and the assigned even-numbered frame indicating consecutively generated odd-numbered frames and assigned even-numbered frames by speeding the frame frequency of the stored input frame and simultaneously displaying the assigned odd-numbered frames. Sequentially generating a frame notification signal '0' indicating a; Calculating an average luminance value of the pixels of the input frame; Comparing the luminance value of each pixel of the assigned odd frame with the calculated average luminance value, a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value is generated. Comparing the luminance value of each pixel of the first frame with the calculated average luminance value and generating a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value; Generating a gray scale conversion control signal '0' or '1' using the luminance difference notification signal and the frame notification signal; Selectively outputting the predetermined low gray level conversion values and high gray level conversion values according to the gray level conversion control signal; And converting the gray level values of each pixel of the assigned odd-numbered frame and even-numbered frame using the predetermined low gray level conversion values or the predetermined high gray level conversion values according to the gray level conversion control signal.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 2, in the liquid crystal display device 100 of the present invention, a thin film transistor for driving the liquid crystal cell Clc at the intersection of the data lines DL1 to DLm and the gate lines GL1 to GLn. A liquid crystal display panel 110 having a thin film transistor (TFT), a frame processor 120 sequentially outputting the odd-numbered frame and the even-numbered frame by speeding the frame frequency of the input frame, and the frame processor 120. The timing controller 130 for controlling the driving timing of the odd-numbered frame and the even-numbered frame assigned to the second frame and the odd-numbered frame and the even-numbered frame assigned according to the frame drive control signal from the timing controller 130 are fixed. In response to the data driver 140 and the gate driving control signal GDC supplied from the timing controller 130 to continuously drive the liquid crystal display panel 110 within a time period. Generating a pulse in order to be provided with a gate driver 150 for supplying to the gate lines (GL1 to GLn).

In addition, the liquid crystal display device 100 of the present invention generates a gamma reference voltage and supplies the gamma reference voltage generator 160 for supplying the data driver 140 to the liquid crystal display panel 110. The common electrode of the liquid crystal cell Clc of the liquid crystal display panel 110 by generating the backlight assembly 170, the inverter 180 for applying a driving voltage and current to the backlight assembly 170, and the common voltage Vcom. It is provided with a common voltage generator 190 for supplying to.

In the liquid crystal display panel 110, liquid crystal is injected between two glass substrates. The data lines DL1 to DLm and the gate lines GL1 to GLn are orthogonal to the lower glass substrate of the liquid crystal display panel 110. TFTs are formed at intersections of the data lines DL1 to DLm and the gate lines GL1 to GLn. The TFT supplies the data on the data lines DL1 to DLm to the liquid crystal cell Clc in response to the scan pulse. The gate electrodes of the TFTs are connected to the gate lines GL1 to GLn, and the source electrodes of the TFTs are connected to the data lines DL1 to DLm. The drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell Clc and the storage capacitor Cst.

The TFT is turned on in response to the scan pulse supplied to the gate terminal via the gate lines GL1 to GLn. When the TFT is turned on, video data on the data lines DL1 to DLm is supplied to the pixel electrode of the liquid crystal cell Clc.

The frame processor 120 doubles the frame frequency of the frame input from the system to generate the odd-numbered and even-numbered frames and calculate an average luminance value of the pixels of the input frame. The frame processor 120 increases or decreases the luminance values of the odd-numbered frame and the even-numbered frame using the predetermined low gray level conversion values and the predetermined high gray level conversion values according to the calculated average brightness value. )

The timing controller 130 outputs the assigned odd-numbered and even-numbered frames having the gray scale value converted by the frame processor 120 to the data driver 140 and simultaneously controls the frame driving timing of the data driver 140. do. In addition, the timing controller 130 uses the horizontal / vertical synchronization signals H and V from the system in response to the clock signal CLK from the system to generate the data drive control signal DDC and the gate drive control signal GDC. Are generated and supplied to the data driver 140 and the gate driver 150, respectively. The data driving control signal DDC includes a source shift clock SSC, a source start pulse SSP, a polarity control signal POL, a source output enable signal SOE, and the gate driving control signal GDC. ) Includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable (GOE), and the like.

The data driver 140 continuously processes the odd-numbered frame and the even-numbered frame having the grayscale value assigned and converted by the frame processor 120 in response to the data driving control signal DDC from the timing controller 130 within a predetermined time. By driving to the liquid crystal display panel 110.

The gate driver 150 sequentially generates scan pulses in response to the gate driving control signal GDC supplied from the timing controller 130 and supplies them to the gate lines GL1 to GLn. In particular, the gate driver 150 sequentially scans the scan pulses during the driving period of the odd-numbered frame assigned to the odd-numbered frame and the odd-numbered frame assigned by the frame processor 120 to the gate lines GL1 to GLn. Scan pulses are sequentially supplied to the gate lines GL1 to GLn during the driving period of the even-numbered frame once again assigned after supplying the power to the.

The gamma reference voltage generator 160 receives the high potential power voltage VDD to generate a positive gamma reference voltage and a negative gamma reference voltage and output the generated negative voltage to the data driver 140. The data driver 140 samples and latches digital video data (such as RGB or RGBW) supplied from the timing controller 130, and then displays the liquid crystal display based on the gamma reference voltage supplied from the gamma reference voltage generator 160. The liquid crystal cell Clc of the panel 110 is converted into an analog data voltage capable of expressing grayscale and supplied to the data lines DL1 to DLm.

The backlight assembly 170 is disposed on the rear surface of the liquid crystal display panel 110 and emits light by driving voltage and current supplied from the inverter 180 to irradiate light to each pixel of the liquid crystal display panel 110.

The inverter 180 converts the square wave signal generated therein into a triangular wave signal and compares the triangular wave signal with a DC power supply voltage VCC supplied from the system to generate a burst dimming signal proportional to the comparison result. . When the burst dimming signal is generated, the driving IC (not shown) in the inverter 180 controls the generation of the AC voltage and the current supplied to the backlight assembly 170 according to the burst dimming signal.

The common voltage generator 190 receives the high potential power voltage VDD to generate the common voltage Vcom and supplies the common voltage Vcom to the common electrodes of the liquid crystal cells Clc of each pixel of the liquid crystal display panel 110.

3 is a block diagram of the frame processor shown in FIG. 2.

Referring to FIG. 3, the frame processor 120 doubles a memory 121 for temporarily storing a frame of a first frame frequency input from a system and a frame frequency of an input frame stored in the memory 121. Frequency conversion control part that outputs the odd frame and even-numbered frame continuously and simultaneously outputs the frame notification signal '1' indicating the odd-numbered frame and the frame notification signal '0' indicating the even-numbered frame. (122), a luminance value calculator 123 for calculating an average luminance value of the pixels of the input frame, and a magnitude of the compared luminance is displayed by comparing the luminance value of each pixel of the assigned frame with the calculated average luminance value. A comparator 124 for outputting a luminance difference notification signal '1' or '0', a luminance difference notification signal from the comparator 124 and a frame notification signal from the frequency conversion controller 122. Using the signal generator 125 to generate the gradation conversion control signal '0' or '1', and the low and high gray level conversion values of each pixel of the frame, and then output the signal to the signal generation unit 125. A look-up table (LUT) 126 for selectively outputting predetermined low gray level conversion values and high gray level conversion values according to the gray level conversion control signal of the control unit; and a lookup table according to the gray level conversion control signal from the signal generator 125. A gray level conversion unit 127 for converting the gray level values of each pixel of the odd-numbered frame and the even-numbered frame assigned by using predetermined low gray level conversion values or predetermined high gray level conversion values selectively outputted from 126. do.

The memory 121 may be implemented as a virtual memory as a memory device for storing frame information, and temporarily stores a frame input from a system.

When the current frame is input from the system, the frequency conversion control unit 122 reads and outputs the input frame stored in the storage unit 121 twice continuously within a predetermined time to double the frame frequency of the input frame. That is, the frequency conversion control unit 122 doubles the input frame of the first frame frequency and sequentially outputs the odd-numbered frame of the doubled second frame frequency and the even-numbered frame of the doubled second frame frequency. Here, the frequency conversion control unit 122 doubles the frame frequency by a dynamic data insertion (DDI) method.

When the current frame is input from the system, the frequency conversion controller 122 converts the first frame frequency of 60 Hz to the second frame frequency of 120 Hz, but is not limited thereto. For example, the frequency conversion controller 122 may be configured to convert the first frame frequency of 50 Hz to the second frame frequency of 60 Hz.

The frequency conversion controller 122 outputs the framed odd numbered frame and outputs a frame notification signal '1' indicating the framed odd number to the signal generator 125 and outputs the assigned even numbered frame. The frame notification signal '0' indicating the even-numbered frame assigned to the output is simultaneously output to the signal generator 125.

The luminance value calculator 123 calculates the luminance value of each pixel of the frame input from the system, and then calculates the calculated quotient as the average luminance value of the pixels of the input frame.

The comparator 124 compares the luminance value of each pixel of the odd frame assigned by the frequency conversion control unit 122 with the average luminance value calculated by the luminance value calculating unit 123 to display the magnitude of the compared luminance value. The luminance difference notification signal '1' or '0' is output. Subsequently, the comparator 124 compares the luminance value of each pixel of the even-numbered frame assigned by the frequency conversion control unit 122 with the magnitude of the average luminance value calculated by the luminance value calculating unit 123 to compare the luminance value. The luminance difference notification signal '1' or '0' indicating the magnitude is output.

According to the present invention, when the luminance value of each pixel of the assigned frame is smaller than the calculated average luminance value, the comparator 124 outputs the luminance difference notification signal '0'. In addition, when the luminance value of each pixel of the assigned frame is greater than the calculated average luminance value, the comparator 124 outputs the luminance difference notification signal '1'. However, the present invention is not limited thereto, but the technical spirit of the present invention may be implemented in the same manner.

The signal generator 125 may control the first input terminal connected to the output terminal of the frequency conversion controller 122, the second input terminal connected to the output terminal of the comparator 124, and the lookup table 126 and the gray scale converter 127. An exclusive logic gate XOR having an output terminal commonly connected to the terminal CON is provided.

The exclusive logic gate (XOR) performs an exclusive logic sum logic operation on the luminance difference notification signal inputted from the comparator 124 through the first input terminal and the frame notification signal inputted from the frequency conversion controller 122 through the second input terminal. Generate the conversion control signal '0' or '1'.

More specifically, when the luminance difference notification signal '0' and the frame notification signal '0' are simultaneously input or the luminance difference notification signal '1' and the frame notification signal '1' are simultaneously input, the exclusive logic gate XOR is input. An exclusive logic sum logic operation of the luminance difference notification signal and the frame notification signal is performed to output the gray scale conversion control signal '0'. On the contrary, when the luminance difference notification signal '0' and the frame notification signal '1' are simultaneously input or the luminance difference notification signal '1' and the frame notification signal '0' are simultaneously input, the exclusive logic gate XOR is input to the input luminance. An exclusive logic sum logic operation of the difference notification signal and the frame notification signal is performed to output the gray scale conversion control signal '1'.

The lookup table 126 stores the low gray level conversion value and the high gray level conversion value of each pixel selectively used for the gray level conversion of each pixel of the odd-numbered and even-numbered frames as shown in FIG. 4. Here, predetermined low gray level conversion values used for low gray level conversion of each pixel of the assigned odd-numbered frame or the even-numbered even frame are stored in the lookup table 126 in the gamma curve form as shown in FIG. 4 (A). . The predetermined high gray level conversion values used for the high gray level conversion of each pixel of the assigned odd-numbered frame or the assigned even-numbered frame are stored in the lookup table 126 in the gamma curve form as shown in FIG. 4 (B). .

When the gray scale conversion control signal '1' is input from the signal generator 125, the lookup table 126 outputs predetermined low gray scale conversion values to the input terminal IN1 of the gray scale converter 127 in response to the signal. do. On the contrary, when the gray scale conversion control signal '0' is input from the signal generator 125, the lookup table 126 transfers the predetermined high gray scale conversion values to the input terminal IN2 of the gray scale converter 127. Output However, the present invention is not limited thereto, and the technical spirit of the present invention may be embodied in the same manner even if the present invention is implemented to the contrary.

The gray scale converter 127 is connected to the control terminal CON connected to the output terminal of the signal generator 125, the input terminal IN1 connected to the output terminal of the lookup table 126, and the output terminal of the frequency conversion controller 122. Input terminal IN2 and an output terminal OUT connected to the input terminal of the timing controller 130.

The gray level conversion process of the gray level conversion unit 127 will be described in more detail as follows.

When the frequency conversion controller 122 outputs the assigned odd frame, the signal generator 125 outputs a gradation conversion control signal '1' or '0', and at the same time, the lookup table 120 controls the gradation conversion. In response to the signal '1' or '0', predetermined low gradation conversion values as shown in Fig. 4A or predetermined high gradation conversion values as shown in Fig. 4B are output.

If the result of the comparison by the comparator 124 is that the luminance value of each pixel of the odd-numbered frame is smaller than the calculated average luminance value, the comparator 124 outputs a luminance difference notification signal '0', in which case the signal generator Reference numeral 125 outputs the gray scale conversion control signal '1' to the control terminal CON of the lookup table 126 and the gray scale converter 127. At this time, the lookup table 120 outputs predetermined low gray level conversion values as shown in FIG. 4A to the input terminal IN1 of the gray level conversion unit 127 in response to the gray level conversion control signal '1'. At the same time, the odd-numbered frame assigned by the frequency conversion control unit 122 is input to the input terminal IN2 of the gray level conversion unit 127. In this case, the gradation converting unit 127 subtracts a predetermined low gradation conversion value of the corresponding pixel from the luminance value of each pixel of the odd-numbered frame assigned in response to the gradation conversion control signal '1', and the odd-numbered frame is assigned. Decreases the luminance value of the pixels. Here, since the predetermined low gray scale conversion value is set to correspond one-to-one to each pixel of the doubled odd frame, the luminance value reduction by the grayscale converter 127 is performed for each pixel of the doubled odd frame.

On the contrary, if the luminance value of each pixel of the odd-numbered frame assigned by the comparator 124 is larger than the calculated average luminance value, the comparator 124 outputs a luminance difference notification signal '1', in which case the signal The generation unit 125 outputs the gray scale conversion control signal '0' to the lookup table 126 and the control terminal CON of the gray scale conversion unit 127. At this time, the lookup table 120 outputs the predetermined high gray level conversion values as shown in FIG. 4B to the input terminal IN1 of the gray level conversion unit 127 in response to the gray level conversion control signal '0'. At the same time, the odd-numbered frame assigned by the frequency conversion control unit 122 is input to the input terminal IN2 of the gray level conversion unit 127. In this case, the gradation converter 127 adds a predetermined high gradation conversion value of the pixel corresponding to the luminance value of each pixel of the odd-numbered frame assigned in response to the gradation conversion control signal '0' to add the odd-numbered frame. Increases the luminance value of the pixels. Since the predetermined high gray level conversion value is set to correspond one-to-one to each pixel of the doubled odd frame, the brightness value increase by the gray level converter 127 is performed for each pixel of the doubled odd frame.

When the frequency conversion controller 122 outputs the even-numbered frame, the signal generator 125 outputs the gray scale conversion control signal '1' or '0', and at the same time, the lookup table 120 In response to the conversion control signal '1' or '0', predetermined low gradation conversion values as shown in Fig. 4A or predetermined high gradation conversion values as shown in Fig. 4B are output.

If the luminance value of each pixel of the even-numbered frame assigned by the comparator 124 is smaller than the calculated average luminance value, the comparator 124 outputs a luminance difference notification signal '0', in which case the signal generator In operation 125, the gray scale conversion control signal '0' is output to the lookup table 126 and the control terminal CON of the gray scale conversion unit 127. At this time, the lookup table 120 outputs the predetermined high gray level conversion values as shown in FIG. 4B to the input terminal IN1 of the gray level conversion unit 127 in response to the gray level conversion control signal '0'. At the same time, the even-numbered frame assigned by the frequency conversion controller 122 is input to the input terminal IN2 of the grayscale converter 127. In this case, the gradation converting unit 127 adds a predetermined high gradation conversion value of the pixel corresponding to the luminance value of each pixel of the even-numbered frame doubled in response to the gradation conversion control signal '0' to distribute the even-numbered frame Increases the luminance value of the pixels. Here, since the predetermined high gray scale conversion value is set to correspond one-to-one to each pixel of the even-numbered even-numbered frame, the brightness value increase by the grayscale conversion unit 127 is performed for each pixel of the even-numbered even-numbered frame.

In contrast, if the luminance value of each pixel of the even-numbered frame assigned by the comparator 124 is larger than the calculated average luminance value, the comparator 124 outputs a luminance difference notification signal '1', in which case the signal The generation unit 125 outputs the gray scale conversion control signal '1' to the lookup table 126 and the control terminal CON of the gray scale conversion unit 127. At this time, the lookup table 120 outputs predetermined low gray level conversion values as shown in FIG. 4A to the input terminal IN1 of the gray level conversion unit 127 in response to the gray level conversion control signal '1'. At the same time, the even-numbered frame assigned by the frequency conversion controller 122 is input to the input terminal IN2 of the grayscale converter 127. In this case, the gradation converting unit 127 subtracts a predetermined low gradation conversion value of the pixel corresponding to the luminance value of each pixel of the even-numbered frame assigned in response to the gradation conversion control signal '1'. Decreases the luminance value of the pixels. Here, since the predetermined low gray scale conversion value is set to correspond one-to-one to each pixel of the even-numbered even-numbered frame, the luminance value reduction by the gray scale conversion unit 127 is performed for each pixel of the even-numbered even-numbered frame.

Meanwhile, the method of increasing or decreasing the luminance value of the present invention is not limited to the above-described implementation, and the technical spirit of the present invention is the same even if the luminance values of the odd-numbered frame and the even-numbered frame are increased or decreased as described above. Is implemented.

As disclosed above, the present invention symmetrically increases or decreases the luminance values of the odd-numbered frame and the even-numbered frame according to the luminance value of each pixel of the input frame, thereby causing the luminance difference between the frames during double-speed driving of the frame frequency. It is possible to prevent the flicker.

As described above, the present invention increases or decreases the luminance value of a frame to which the frame frequency is doubled according to the luminance value of each pixel of the input frame, thereby preventing flicker caused by the luminance difference between frames during double-speed driving of the frame frequency. can do.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

Claims (32)

The frame frequency of the input frame is doubled to generate odd-numbered and even-numbered frames, and the predetermined low gray level conversion values and predetermined high gray level conversion values are generated according to average luminance values of the pixels of the input frame. A frame processor for increasing or decreasing the luminance values of the assigned odd-numbered frame and the even-numbered frame; A timing controller controlling driving timing of the assigned odd-numbered frame and the even-numbered frame having the gray scale value converted by the frame processor; And According to the control of the timing controller, the data driver to drive the assigned odd-numbered frame and even-numbered frame to the liquid crystal display panel continuously within a predetermined time. Liquid crystal display comprising a. The method of claim 1, The frame processor, A memory for temporarily storing the input frame; The frame notification signal '1' and the assigned even-numbered frame for displaying the assigned odd-numbered frame in succession while simultaneously outputting the assigned odd-numbered frame and even-numbered frame by speeding the frame frequency of the input frame stored in the memory. A frequency conversion controller for sequentially outputting a frame notification signal '0' indicating a frame; A luminance value calculator configured to calculate an average luminance value of the pixels of the input frame; The luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value is output by comparing the luminance value of each pixel of the assigned odd-numbered frame with the calculated average luminance value, and the assigned excellent value A comparator for comparing the luminance value of each pixel of the first frame with the magnitude of the calculated average luminance value and outputting a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value; A signal generator for generating a gradation conversion control signal '0' or '1' using the luminance difference notification signal and the frame notification signal; Store predetermined low gray level conversion values and the predetermined high gray level conversion values, which are selectively used for gray level conversion of each of the assigned odd-numbered frame and even-numbered frame, and according to the gray level conversion control signal; A look-up table for selectively outputting low gray scale conversion values and high gray scale conversion values; And The gray level value of each pixel of the assigned odd-numbered frame and even-numbered frame is obtained by using the predetermined low gray level conversion values or the predetermined high gray level conversion values selectively output from the lookup table according to the gray level conversion control signal. Gradation converter to convert Liquid crystal display comprising a. The method of claim 2, The frequency conversion control unit simultaneously outputs the frame notification signal '1' indicating the odd-numbered frame assigned when outputting the assigned odd-numbered frame, and outputs the assigned even-numbered frame. And simultaneously outputting the frame notification signal '0' indicating the even-numbered frame. The method of claim 3, wherein The luminance value calculator calculates a luminance value of each pixel of the input frame and then calculates an average of the calculated luminance values as an average luminance value of the pixels of the input frame. Device. The method of claim 4, wherein And the comparator outputs the luminance difference notification signal '0' when the luminance value of each pixel of the assigned odd-numbered frame or even-numbered frame is smaller than the calculated average luminance value. The method of claim 5, wherein And the comparator outputs the luminance difference notification signal '1' when the luminance value of each pixel of the assigned odd-numbered frame or even-numbered frame is larger than the calculated average luminance value. The method of claim 6, The signal generator, An exclusive logic gate having a first input terminal connected to an output terminal of the frequency conversion controller, a second input terminal connected to an output terminal of the comparator, and an output terminal commonly connected to the lookup table and a control terminal of the gray scale conversion unit. Liquid crystal display comprising a. The method of claim 7, wherein The exclusive logic gate controls the gray level conversion when the luminance difference notification signal '0' and the frame notification signal '0' are simultaneously input or the luminance difference notification signal '1' and the frame notification signal '1' are simultaneously input. And a signal '0'. The method of claim 8, When the luminance difference notification signal '0' and the frame notification signal '1' are simultaneously input or the luminance difference notification signal '1' and the frame notification signal '0' are simultaneously input, the exclusive logic sum gate controls the gray level conversion. And a signal '1'. The method of claim 9, And the look-up table outputs the predetermined low gray level conversion values to the gray level conversion unit when the gray level conversion control signal '1' is input. The method of claim 10, And the lookup table outputs the predetermined high gray level conversion values to the gray level conversion unit when the gray level conversion control signal '0' is input. The method of claim 11, The gray level converting unit converts the predetermined low gray level conversion values according to the gray level conversion control signal '1' when the attached odd-numbered frame, the gray level conversion control signal '1', and the predetermined low gray level conversion values are input. And reducing the luminance value of each pixel of the assigned odd frame. The method of claim 11, The gradation converter is configured to convert the predetermined high gradation conversion values according to the gradation conversion control signal '0' when the assigned odd frame, the gradation conversion control signal '0', and the predetermined high gradation conversion values are input. And increasing a luminance value of pixels of the assigned odd frame. The method of claim 11, The gradation converter is configured to convert the predetermined high gradation conversion values according to the gradation conversion control signal '0' when the assigned even-numbered frame, the gradation conversion control signal '0', and the predetermined high gradation conversion values are input. And increasing the luminance value of the pixels of the even-numbered frame. The method of claim 11, The gray level converting unit may convert the predetermined low gray level conversion values according to the gray level conversion control signal '1' when the assigned even-numbered frame, the gray level conversion control signal '1', and the predetermined low gray level conversion values are input. And reducing the luminance value of the pixels of the even-numbered frame. A memory for temporarily storing an input frame; The frame frequency of the input frame stored in the memory is doubled to continuously output the doubled odd frame and the doubled even frame, and at the same time, the frame notification signal '1' and the doubled even frame to display the doubled odd frame. A frequency conversion controller for sequentially outputting a frame notification signal '0' indicating the second frame; A luminance value calculator configured to calculate an average luminance value of the pixels of the input frame; The luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value is output by comparing the luminance value of each pixel of the assigned odd-numbered frame with the calculated average luminance value, and the assigned excellent value A comparator for comparing the luminance value of each pixel of the first frame with the magnitude of the calculated average luminance value and outputting a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value; A signal generator for generating a gradation conversion control signal '0' or '1' using the luminance difference notification signal and the frame notification signal; Store predetermined low gray level conversion values and the predetermined high gray level conversion values, which are selectively used for gray level conversion of each of the assigned odd-numbered frame and even-numbered frame, and according to the gray level conversion control signal; A look-up table for selectively outputting low gray scale conversion values and high gray scale conversion values; And The gray level value of each pixel of the assigned odd-numbered frame and even-numbered frame is obtained by using the predetermined low gray level conversion values or the predetermined high gray level conversion values selectively output from the lookup table according to the gray level conversion control signal. Gradation converter to convert Liquid crystal display comprising a. Generating a doubled odd numbered frame and an even numbered frame by speeding the frame frequency of the input frame; Increasing or decreasing luminance values of the assigned odd-numbered frame and even-numbered frame using predetermined low gray level conversion values and predetermined high gray level conversion values according to average luminance values of pixels of the input frame; And Driving the assigned odd-numbered frame and the even-numbered frame having the increased or decreased luminance value continuously to a liquid crystal display panel within a predetermined time; Method of driving a liquid crystal display comprising a. The method of claim 17, The assigned frame generation step, Temporarily storing the input frame; Speeding the frame frequency of the stored input frame to generate the assigned odd-numbered frame and even-numbered frame; And Generating a frame notification signal '1' indicating the assigned odd-numbered frame and a frame notification signal '0' indicating the assigned even-numbered frame; Method of driving a liquid crystal display comprising a. The method of claim 18, The brightness value increment step, Calculating an average luminance value of the pixels of the input frame; Generating a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value by comparing the luminance value of each pixel of the assigned odd frame with the calculated average luminance value; Generating a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value by comparing the luminance value of each pixel of the assigned even-numbered frame with the calculated average luminance value; Generating a gray scale conversion control signal '0' or '1' using the luminance difference notification signal and the frame notification signal; Selectively outputting predetermined low gray scale conversion values and predetermined high gray scale conversion values according to the gray scale conversion control signal; And Converting the gradation value of each pixel of the assigned odd-numbered frame and even-numbered frame using the predetermined low gradation conversion values or the predetermined high gradation conversion values according to the gradation conversion control signal. Method of driving a liquid crystal display comprising a. The method of claim 19, In the frame notification signal generation step, Generating the frame notification signal '1' indicating the assigned odd-numbered frame when the assigned odd-numbered frame is generated, and displaying the assigned even-numbered frame when the even-numbered even-numbered frame is generated. And a frame notification signal '0'. The method of claim 20, In the brightness value calculating step, And after calculating the luminance value of each pixel of the input frame, calculating the average value of the calculated luminance values as the average luminance value of the pixels of the input frame. The method of claim 21, In the luminance difference notification signal generating step, And when the luminance value of each pixel of the assigned odd-numbered frame or even-numbered frame is smaller than the calculated average luminance value, the luminance difference notification signal '0' is generated. The method of claim 22, In the luminance difference notification signal generating step, And when the luminance value of each pixel of the assigned odd-numbered frame or even-numbered frame is larger than the calculated average luminance value, the luminance difference notification signal '1' is generated. The method of claim 23, In the gradation conversion control signal generating step, When the luminance difference notification signal '0' and the frame notification signal '0' are simultaneously generated or the luminance difference notification signal '1' and the frame notification signal '1' are simultaneously generated, the gradation conversion control signal '0' is generated. A driving method of a liquid crystal display device, characterized in that generated. The method of claim 24, In the gradation conversion control signal generating step, When the luminance difference notification signal '0' and the frame notification signal '1' are simultaneously generated or the luminance difference notification signal '1' and the frame notification signal '0' are simultaneously generated, the gray scale conversion control signal '1' is generated. A driving method of a liquid crystal display device, characterized in that generated. The method of claim 25, In the predetermined low gradation conversion value generating step, And outputting the predetermined low gray level conversion values when the gray level conversion control signal '1' is generated. The method of claim 26, In the predetermined high gradation conversion value generating step, And outputting the predetermined high gradation conversion values when the gradation conversion control signal '0' is generated. The method of claim 27, In the step of increasing or decreasing the brightness value, When the assigned odd-numbered frame and the gradation conversion control signal '1' are generated and the predetermined low gradation conversion values are output, the predetermined low gradation conversion values are used according to the gradation conversion control signal '1'. And a luminance value of each pixel of the assigned odd frame is reduced. The method of claim 27, In the step of increasing or decreasing the brightness value, When the assigned odd-numbered frame and the gradation conversion control signal '0' are generated and the predetermined high gradation conversion values are output, the predetermined high gradation conversion values are used according to the gradation conversion control signal '0'. A method of driving a liquid crystal display device, characterized in that to increase the luminance value of the pixels of the assigned odd frame. The method of claim 27, In the step of increasing or decreasing the brightness value, When the even-numbered even frame and the gradation conversion control signal '0' are generated and the predetermined high gradation conversion values are output, the predetermined high gradation conversion values are used according to the gradation conversion control signal '0'. And increasing the luminance value of the pixels of the even-numbered frame. The method of claim 27, In the step of increasing or decreasing the brightness value, When the even-numbered even frame and the gradation conversion control signal '1' are generated and the predetermined low gradation conversion values are output, the predetermined low gradation conversion values are used according to the gradation conversion control signal '1'. A method of driving a liquid crystal display device, characterized by reducing the luminance value of the pixels of the even-numbered frame. Temporarily storing the input frame; The frame notification signal '1' and the assigned even-numbered frame indicating consecutively generated odd-numbered frames and assigned even-numbered frames by speeding the frame frequency of the stored input frame and simultaneously displaying the assigned odd-numbered frames. Sequentially generating a frame notification signal '0' indicating a; Calculating an average luminance value of the pixels of the input frame; Comparing the luminance value of each pixel of the assigned odd frame with the calculated average luminance value, a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value is generated. Comparing the luminance value of each pixel of the first frame with the calculated average luminance value and generating a luminance difference notification signal '1' or '0' indicating the magnitude of the compared luminance value; Generating a gray scale conversion control signal '0' or '1' using the luminance difference notification signal and the frame notification signal; Selectively outputting the predetermined low gray level conversion values and high gray level conversion values according to the gray level conversion control signal; And Converting the gradation value of each pixel of the assigned odd-numbered frame and even-numbered frame using the predetermined low gradation conversion values or the predetermined high gradation conversion values according to the gradation conversion control signal. Method of driving a liquid crystal display comprising a.

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