KR101214658B1 - Appratus and method for driving LCD - Google Patents

Abstract

The present invention provides a driving device of a liquid crystal display device that can linearly convert a gray level value of a still image or video frame in a liquid crystal display device that doubles the frame frequency. Frequency converting means for continuously outputting the same frames in the apparatus; Frame determination means for determining whether the input frame is a still image or a moving image frame and outputting a still image notification signal or a moving image notification signal according to a determination result; First gray level converting means for converting the gray level values of pixels of the same frames continuously input within the predetermined time from the frequency converting means through one gray level transition; And second gray level converting means for converting the gray level values of pixels of the same frames input from the first gray level converting means through linear grayscale transition steps in response to the still image alert signal or the video alert signal.

LCD, Still image, Video, Frame, Gradation, Linear

Description

Driving apparatus of liquid crystal display device and driving method thereof {Appratus and method for driving LCD}

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

2 is a configuration diagram of a general liquid crystal display device.

3 is a configuration diagram of a driving device of a liquid crystal display device according to an exemplary embodiment of the present invention.

4A and 4B are gradation conversion characteristic diagrams by the first gradation converter in Fig. 3;

5A and 5B are gradation conversion characteristic diagrams by the second gradation converter in Fig. 3;

FIG. 6 is a configuration diagram of the frequency converter in FIG. 3. FIG.

7 is a configuration diagram of a frame discriminator in FIG. 3.

8 is a configuration diagram of a first gradation converter in FIG. 3;

9 is a configuration diagram of a second gradation converter in FIG. 3;

10 is a flowchart illustrating a method of driving a liquid crystal display according to an embodiment of the present invention.

FIG. 11 is a flowchart illustrating a frame frequency conversion process in FIG. 10 in detail; FIG.

FIG. 12 is a flowchart illustrating a detailed grayscale conversion process in FIG. 10; FIG.

FIG. 13 is a flowchart illustrating a process of generating a notification signal in FIG. 10; FIG.

14A and 14B are detailed flowcharts illustrating the linear gray scale conversion process of FIG. 10.

Explanation of symbols on the main parts of the drawings

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

120: data driver 130: gate driver

140: gamma reference voltage generator 150: backlight assembly

160: inverter 170: common voltage generator

180: gate driving voltage generator 190: timing controller

200: driving device of the liquid crystal display 210: frequency converter

220: frame discriminator 230: first gradation converter

240: second gradation converter

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a driving device and a driving method of a liquid crystal display device capable of linearly converting a gray level value of a still image or a moving image frame in a liquid crystal display device having a double frame frequency.

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 connected to the pixel electrode of the liquid crystal cell Clc and one electrode of the storage capacitor Cst. Connected.

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

The storage capacitor Cst serves to charge the data voltage applied from the data line DL when the TFT is turned on to maintain the voltage of the liquid crystal cell Clc constant.

When a 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 to apply a voltage on the data line DL 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 configuration of a general liquid crystal display device having pixels having such a structure will be described with reference to FIG. 2.

2 is a configuration diagram of a general liquid crystal display device.

Referring to FIG. 2, the liquid crystal display device 100 includes a thin film transistor TFT for driving data lines DL1 to DLm and gate lines GL1 to GLn and driving the liquid crystal cell Clc at an intersection thereof. A liquid crystal display panel 110 having a thin film transistor, a data driver 120 for supplying data to the data lines DL1 to DLm of the liquid crystal display panel 110, and a gate of the liquid crystal display panel 110. A gate driver 130 for supplying scan pulses to the lines GL1 to GLn, a gamma reference voltage generator 140 for generating a gamma reference voltage and supplying it to the data driver 120, and a liquid crystal display panel 110. ) Generates a backlight assembly 150 for irradiating light, an inverter 160 for applying an alternating voltage and current to the backlight assembly 160, and a common voltage Vcom to generate liquid crystals of the liquid crystal display panel 110. A common voltage generator 170 for supplying the common electrode of the cell Clc, A timing for controlling the gate driving voltage generator 180 for generating the high voltage VGH and the gate low voltage VGL and supplying the gate voltage 130 to the gate driver 130, and for controlling the data driver 120 and the gate driver 130. The controller 190 is provided.

In the liquid crystal display panel 110, liquid crystal is injected between two glass substrates. On the lower glass substrate of the liquid crystal display panel 110, the data lines DL1 to DLm and the gate lines GL1 to GLn are orthogonal. 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 data driver 120 supplies data to the data lines DL1 to DLm in response to the data driving control signal DDC supplied from the timing controller 190, and digital video data supplied from the timing controller 190. After sampling and latching the RGB, the liquid crystal cell Clc of the liquid crystal display panel 110 is converted into an analog data voltage capable of expressing gray scale based on the gamma reference voltage supplied from the gamma reference voltage generator 140. Supply to the data lines DL1 to DLm.

The gate driver 130 sequentially generates scan pulses, that is, gate pulses, in response to the gate driving control signal GDC and the gate shift clock GSC supplied from the timing controller 190, thereby providing the gate lines GL1 to GLn. To feed. The gate driver 130 determines the high level voltage and the low level voltage of the scan pulse in accordance with the gate high voltage VGH and the gate low voltage VGL supplied from the gate drive voltage generator 180, respectively.

The gamma reference voltage generator 140 receives a high potential power supply voltage VDD to generate a positive gamma reference voltage and a negative gamma reference voltage and output the same to the data driver 120.

The backlight assembly 150 is disposed on the rear surface of the liquid crystal display panel 110 and emits light by an AC voltage and a current supplied from the inverter 160 to irradiate light to each pixel of the liquid crystal display panel 110.

The inverter 160 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 a burst dimming signal determined according to an internal square wave signal is generated, a driving IC (not shown) for controlling the generation of AC voltage and current in the inverter 160 is supplied to the backlight assembly 150 according to the burst dimming signal. Control the generation of alternating voltage and current.

The common voltage generator 170 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.

The gate driving voltage generator 180 receives the high potential power voltage VDD to generate the gate high voltage VGH and the gate low voltage VGL to supply the gate driver 130 to the gate driver 130. Here, the gate driving voltage generation unit 180 generates a gate high voltage VGH that is greater than or equal to the threshold voltage of the TFTs provided in each pixel of the liquid crystal display panel 110, and the gate low voltage that is less than or equal to the threshold voltage of the TFT. VGL). The gate high voltage VGH and the gate low voltage VGL generated in this way are used to determine the high level voltage and the low level voltage of the scan pulse generated by the gate driver 130, respectively.

The timing controller 190 supplies digital video data RGB, which is supplied from a digital video card (not shown), to the data driver 120, and also horizontal / vertical synchronization signals H and V according to the clock signal CLK. The data driving control signal DDC and the gate driving control signal GDC may be generated and supplied to the data driver 120 and the gate driver 130, 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 a gate driving control signal GDC. ) Includes a gate start pulse (GSP) and a gate output enable (GOE).

The liquid crystal display device 100 having such a configuration and function is generally driven at 60 Hz, but in recent years, a technique for driving the liquid crystal display device 100 at 120 Hz has been developed in order to improve moving images.

When the liquid crystal display 100 is driven at 120 Hz, gray data conversion is performed while maintaining the average luminance of two frames the same as that of one frame when driven at 60 Hz. Flicker is visible to the naked eye due to the alternating display of low gray on the screen.

The present invention has been made to solve the above problems, and an object of the present invention is to drive a liquid crystal display device capable of linearly converting a gray level value of a still image or a video frame in a liquid crystal display device having a double frame frequency. An apparatus and a driving method are provided.

SUMMARY OF THE INVENTION An object of the present invention is to provide a driving device and a driving method of a liquid crystal display device capable of continuously driving the same frames in which gray levels are linearly converted within a predetermined time in a liquid crystal display device having a double frame frequency.

An object of the present invention is to continuously drive the same frame in which the gray level is linearly converted within a predetermined time in a liquid crystal display device that doubles the frame frequency, thereby preventing the screen flicker caused by the sudden gray level conversion A driving device and a driving method of a display device are provided.

A driving device of the liquid crystal display device of the present invention for achieving the above object, frequency conversion means for continuously receiving the frame to convert the frame frequency to output the same frame within a predetermined time; Frame determination means for determining whether the input frame is a still image or a moving image frame and outputting a still image notification signal or a moving image notification signal according to a determination result; First gray level converting means for converting the gray level values of pixels of the same frames continuously input within the predetermined time from the frequency converting means through one gray level transition; And second gray level converting means for converting the gray level values of pixels of the same frames input from the first gray level converting means through linear grayscale transition steps in response to the still image alert signal or the video alert signal.

The frequency converting means may include: a storage unit for temporarily storing an input frame; And a frequency conversion controller configured to temporarily store the input frame in the storage unit, double the first frame frequency to the second frame frequency, and continuously read and output the frame in the storage unit within a predetermined time.

The frame discrimination unit may include a storage unit for storing one or more previous frames of the input current frame; A frame discrimination controller configured to store the previous frame in the storage unit, and read out the previous frame as the current frame is input to control determination of an image state of the current frame; A system value calculation unit for calculating gray level difference values of corresponding pixels of the previous frame and the current frame under the control of the frame determination unit; An adder for adding the calculated gray level differences according to the control of the frame discrimination controller; And the second gray level conversion by generating the still image notification signal or the video notification signal according to a comparison result by comparing the addition value added by the adding unit with a predetermined reference gray value under the control of the frame discrimination controller. And a notification signal generator for outputting the means.

The notification signal generator, when the addition value is smaller than the predetermined reference gradation value, judging the current frame as a still image frame to generate the still image notification signal and outputs to the second tone conversion means. do.

The notification signal generator, when the addition value is greater than the predetermined reference gray value, determine the current frame as a video frame, characterized in that for generating the video notification signal and outputs to the second gray scale conversion means.

The gray level value calculating unit may calculate gray level differences between the current frame and corresponding pixels of one previous frame. Alternatively, the gray value calculation unit may calculate gray level differences between the current frame and corresponding pixels of at least two previous frames.

The first gradation converting means includes: a gradation detector for detecting gradation values of pixels of the same frames continuously input from the frequency converting means within a predetermined time; A gray scale calculator for calculating a low gray scale conversion value and a high gray scale converted value to be converted by using the gray scale value detected by the gray scale detector and a predetermined reference gray scale value; A first gradation conversion unit for converting gradations of pixels of the odd and even frames among the same input frames to the calculated low gradation conversion value and the high gradation conversion value at one time; And a second gray level conversion unit for converting the gray levels at once from the calculated low gray level conversion value and the high gray level conversion value to the gray level values of the pixels of the odd and even frames, respectively.

The gradation calculator calculates the low gradation value by subtracting a predetermined reference gradation value from the detected gradation value, and simultaneously calculates the high gradation value by adding the predetermined reference gradation value to the detected gradation value. It is characterized by.

The first grayscale converter converts the grayscales of the pixels of the odd-numbered frame to the low grayscale conversion value at once and converts the grayscales of the pixels of the even-numbered frame into the low grayscale conversion value. It is characterized by converting to high gradation by shifting the value at once.

The second gray scale conversion unit converts the gray scale at once from the calculated low gray scale conversion value to the gray scale values of the pixels of the odd frame, and at the same time, the gray scale of the pixels of the even frame from the calculated high gray scale conversion value. It is characterized by converting the gradation at once up to the value.

The second gradation converting means calculates a difference value between the detected gradation value and the calculated low gradation conversion value or the high gradation conversion value, and calculates a unit transition value using the difference value and a predetermined number of transition times. Transition step calculation unit for; The gray level of the pixels of the odd-th video frame is shifted by the calculated unit transition value over the predetermined number of transitions, and converted into the calculated low gray level conversion value, and the gray level of the pixels of the even-th video frame is converted to the predetermined number. A video grayscale conversion unit for shifting the calculated unit transition value by the number of transitions and converting the calculated high grayscale conversion value to the calculated high gray scale conversion value; And converting the calculated low gray scale conversion value by the calculated unit transition value over the predetermined number of transitions, and converting the calculated low gray scale conversion value into gray scale values of pixels of the odd-numbered still image frame, and converting the calculated high gray scale conversion value. And a still image gradation converter for shifting by the calculated unit transition value over the number of transitions and converting the calculated unit transition values into gradation values of pixels of the even-numbered still image frame.

The transition step calculating unit divides the calculated difference value by the predetermined number of transitions, calculates the quotient as the unit transition value, and outputs the gradation value to the video grayscale conversion unit and the still image grayscale conversion unit.

The video grayscale conversion unit alternately shifts the gray levels of the pixels of the odd and even video frames by the calculated unit transition value over the predetermined number of transitions, and counts the number of transitions every gray level transition. It features.

When the gray level of the pixels of the radix video frame is converted into the calculated low gray level conversion value, the video gray level converting unit converts the gray levels of the pixels of the radix video frame if the number of transitions and the predetermined number of transitions are the same. The gray scale transition is stopped by determining that the calculated low gray scale conversion value has been converted.

The video grayscale conversion unit converts the grayscales of the pixels of the even-th video frame to the calculated high grayscale conversion value, and if the counted transition number is equal to the predetermined transition number, the grayscales of the pixels of the even-numbered video frame are equal. The gray scale transition is stopped by determining that the converted high gray value is converted to the calculated high gray scale conversion value.

The still image gradation converting unit alternately shifts the calculated low gradation conversion value and the high gradation conversion value by the calculated unit transition value over the predetermined number of transitions, and counts the number of transitions for each gradation transition. It is characterized by.

The still image gradation converting unit converts the calculated low gradation conversion value into gradation values of pixels of the odd-numbered still image frame, and the calculated low gradation conversion value is equal to the counted transition number. The grayscale transition is stopped by determining that the grayscale value of the pixels of the odd-numbered still image frame has been converted.

The still image gradation converting unit converts the calculated high gradation conversion value into gradation values of the pixels of the even-numbered still image frame, and the calculated high gradation conversion value is equal to the counted transition number. The grayscale transition is stopped by determining that the pixels of the even-th still image frame are converted to grayscale values.

According to the present invention, when the current frame is input while the previous frame is stored, converting the first frame frequency to the second frame frequency to generate the same frames continuously driven within a predetermined time; Translating and converting the grayscale values of the pixels of the generated frames to be driven at the second frame frequency at one time; Determining whether the current frame is a still image or a video frame using the previous frame and generating a still image notification signal or a video notification signal according to a determination result; And in response to the video notification signal or the still image notification signal, converting the gray level values of pixels of the frames whose gray levels are converted in the gray level conversion step through linear gray level transition steps.

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

3 is a configuration diagram of a driving device of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the driving apparatus 200 of the liquid crystal display device of the present invention includes a frequency converter 210 for receiving a frame, converting a frame frequency, and continuously outputting the same frames, and the input frame being a still image. Or a frame determiner 220 for outputting a still image notification signal or a video notification signal according to a determination result, and a gray value of pixels of frames continuously input within a predetermined time from the frequency converter 210 according to the determination result. Linearly convert the gradation values of the pixels of the still image frames continuously input within a predetermined time from the gradation converter 210 in response to the still image notification signal and the first gradation converter 230 for converting the gradation through one gradation transition. The gradation transition is performed through the gradation transition stages and output to the frame output stage or from the gradation converter 210 in response to the video notification signal. And a second gray scale converter 240 for linearly converting gray values of pixels of continuously input video frames within a predetermined time and outputting the gray scale values to the frame output terminal.

The frequency converter 210 temporarily stores the input frame, doubles the first frame frequency to the second frame frequency, and continuously reads the stored frame twice within a predetermined time to output the first frame converter 230. . Here, the frequency converter 210 doubles the frame frequency by a dynamic data insertion (DDI) method. More specifically, the frequency converter 210 temporarily stores the input current frame and reads the same frame twice within a predetermined time so that the same frames are continuously Output it.

When the current frame is input through the frame input terminal, the frequency converter 210 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 converter 210 may be implemented to convert the first frame frequency of 50 Hz to the second frame frequency of 60 Hz.

The frame discriminator 220 stores the previous frame of the input current frame, reads the previous frame as the current frame is input, and calculates gray level differences between the previous frame and the corresponding pixels of the current frame. Subsequently, the frame discriminator 220 adds the calculated gradation difference values, compares the added value with a predetermined reference gradation value, and generates a still image notification signal or a video notification signal according to a comparison result to generate a second gradation converter ( 240).

The first gradation converter 230 detects gradation values of pixels of the same frames continuously input from the frequency converter 210 within a predetermined time, and then converts the gradation values using the detected gradation values and a predetermined reference gradation value. The low gray scale conversion value and the high gray scale conversion value are calculated. Subsequently, the first gray scale converter 230 converts the gray scales by converting the gray scales of the pixels of the odd and even frames to the low gray scale conversion value and the high gray scale conversion value at once, and converts the gray scales. The gray level is converted at a time from the value and the high gray level conversion value to the gray level values of the pixels of the odd and even frames, and the gray level is converted and output to the second gray scale converter 240. As shown in FIG. 4A, the first grayscale converter 230 rapidly converts the grayscale value 'DG' of the pixel of the inputted odd frame to the low grayscale converted value 'LG', and simultaneously inputs the even-numbered frame. The grayscale value 'DG' of the pixel of D is rapidly converted to the high gray scale conversion value 'HG'. As shown in FIG. 4B, the second gray level converter 230 rapidly converts the gray level from the calculated low gray level conversion value 'LG' to 'DG', which is the gray level value of the pixel of the odd frame, and simultaneously calculates the high gray level. The gray level is rapidly converted from the gray level conversion value 'HG' to 'DG', which is a gray level value of the pixel of the even frame.

The second gradation converter 240 calculates a difference value between the gradation value detected by the first gradation converter 230 and the calculated low gradation conversion value or high gradation conversion value, and then uses the difference value and the predetermined number of transition times. To calculate the unit transition value. When the unit transition value is calculated as described above, the second gray scale converter 240 converts the gray levels of the pixels of the radix-th video frame by the unit transition value calculated over a predetermined number of transitions, and converts them to the low gray scale conversion value calculated. The gray level of the pixels of the first video frame is shifted by the unit transition value calculated over a predetermined number of transitions, and then converted to the high gray level conversion value, which is calculated. In addition, the second gray scale converter 240 converts the calculated low gray scale conversion value by a unit transition value calculated over a predetermined number of transitions, converts the gray scale values into pixels of the odd-numbered still image frame, and calculates the high gray scale conversion. The value is shifted by the unit transition value calculated over a predetermined number of transition times, and is converted to the grayscale value of the pixels of the even-numbered still image frame and output to the frame output terminal. As shown in FIG. 5A, the second grayscale converter 240 linearly decreases the grayscale value 'DG' of the pixel of the odd-numbered video frame by a calculated unit transition value over a predetermined number of transition times. The high gray scale conversion value calculated by converting the gray scale conversion value 'LG' and linearly increasing the gray scale value 'DG' of the pixel of the even-th input video frame input by the calculated unit transition value over a predetermined number of transition times. Convert to 'HG'. As shown in FIG. 5B, the second gray scale converter 240 linearly increases the calculated low gray scale conversion value 'LG' by the calculated unit transition value over a predetermined number of transition times, and thereby radix-th still image frame. Converts the gradation value 'DG' of the pixel of the pixel into linearly and linearly decreases the calculated high gradation conversion value 'HG' by the calculated unit transition value over a predetermined number of transitions, To DG '.

6 is a configuration diagram of the frequency converter in FIG. 3.

Referring to FIG. 6, the frequency converter 210 temporarily stores an input frame in a storage unit 211, temporarily stores an input frame in the storage unit 211, and stores a first frame frequency in a second frame. And a frequency conversion control unit 212 for continuously reading out and outputting the frame of the storage unit 211 within a predetermined time by speeding at a frequency.

The storage unit 211 may be implemented as a virtual memory as a memory device for storing frame information. The storage unit 211 temporarily stores the current frame written by the frequency conversion control unit 212.

When the current frame is input through the frame input terminal, the frequency conversion controller 212 temporarily stores the current frame in the storage unit 211, reads the frame of the storage unit 211 twice within a predetermined time, and continuously performs the first gradation. By outputting to the converter 230, the first frame frequency is converted into the second frame frequency.

FIG. 7 is a configuration diagram of the frame discriminator in FIG. 3.

Referring to FIG. 7, the frame discriminator 220 stores a storage unit 221 for storing one or more previous frames of the input current frame, stores the previous frame in the storage unit 221, and inputs the current frame. The gray level difference value between the corresponding frame of the previous frame and the current frame according to the control of the frame determination unit 222 and the frame determination unit 222 for reading out the previous frame and controlling the determination of the image state of the current frame. An addition unit 224 for adding the tone difference values calculated by the even value calculation unit 223 under the control of the even-value calculation unit 223 and the frame discrimination control unit 222; According to the control of the frame discrimination controller 222, the addition value added by the adder 224 and the predetermined reference gray value are compared to generate a first selection signal or a second selection signal according to a comparison result, and the multiplexer ( Output to 240) And a selection signal generating section 225 for group.

The storage unit 221 stores one or more previous frames written by the frame determination controller 222.

The frame discrimination control unit 222 stores the previous frame in the storage unit 221 and then, when the current frame is input through the frame input terminal, reads one or more previous frames from the storage unit 221 to determine one or more previous frames and the current frame. The gradation value calculation unit 223 outputs the gradation value. When the gray scale difference values calculated from the gray scale calculator 223 are input, the frame determination controller 222 transfers the calculated gray scale difference values to the adder 224. When the added value added from the adder 224 is input, the frame discrimination controller 222 transfers the inputted added value to the selection signal generator 225.

Even if the current frame and the previous frame are input from the frame discrimination controller 222, the value calculating unit 223 calculates gray level differences between the pixels corresponding to the previous frame and the current frame and outputs the gray level differences to the frame discrimination controller 222. .

Although the present invention is implemented such that the value calculating unit 223 calculates the gray level difference values using one previous frame and the current frame, the present invention is not limited thereto. It may be implemented to calculate gray level differences using the frames and the current frame. In this case, the frame discrimination control unit 222 reads a plurality of previous frames from the storage unit 221 and transfers the previous frames to the value calculating unit 223.

When the gray level difference values calculated by the gray level calculation unit 223 are input, the adder 224 adds all of the gray level difference values and outputs the added value to the frame discrimination controller 222.

When the addition value added by the adder 224 is input, the notification signal generator 225 compares this addition value with a predetermined reference gray value and generates a still image notification signal or a video notification signal according to a comparison result. Output to the second gray scale converter 240. If the result of the comparison is smaller than the predetermined reference gray value, the notification signal generator 225 determines the current frame as a still image frame, generates a still image notification signal '0', and outputs it to the second gray scale converter 240. do. If the result of the comparison is greater than the predetermined reference gray value, the notification signal generator 225 determines the current frame as a video frame, generates a video notification signal '1', and outputs it to the second gray scale converter 240.

FIG. 8 is a configuration diagram of the first gradation converter in FIG. 3.

Referring to FIG. 8, the first gray scale converter 230 may include a gray scale detector 231 and a gray scale detector 231 for detecting gray scale values of pixels of the same frames continuously input from the frequency converter 230 within a predetermined time. Gradation calculator 232 for calculating the low gradation value and the high gradation value to be converted by using the gradation value detected by the reference value and the predetermined reference gradation value, and the pixels of the odd and even frames. The first gray level converting unit 223 and the gray level calculating unit 232 for converting the gray level by converting the gray level to the low gray level conversion value and the high gray level conversion value calculated by the gray level calculating unit 232 at once And a second grayscale conversion unit 234 for converting the grayscale by converting the grayscale values of the pixels of the odd and even frames at once from the low gray scale conversion value and the high gray scale conversion value calculated by each.

The gray scale detector 231 detects gray scale values of pixels of the same frames continuously input from the frequency converter 210 within a predetermined time period, and outputs the gray scale values to the gray scale calculator 232.

The gray scale calculator 232 calculates a low gray scale converted value to be converted by subtracting a predetermined reference gray value from the gray scale value detected by the gray scale detector 231, and simultaneously detects the gray scale detected by the gray scale value detector 231. A predetermined reference gradation value is added to the value to calculate a high gradation conversion value to be converted. For example, when the gradation value detected by the gradation detector 231 is '50 gradation 'and the predetermined reference gradation value is' 8 gradation ', the gradation calculator 232 selects from the detected gradation value '50 gradation'. The reference gray scale value '8 gray scales' is calculated by subtracting the reference gray scale value' 8 gray scales', and the predetermined gray scale value '8 gray scales' is added to the detected gray scale value '50 gray scales'. 58 gray levels' are calculated and output to the first and second gray level converters 233 and 234.

The first grayscale converter 233 converts the grayscales of pixels of the odd frame among the same frames continuously input within a predetermined time period to the low grayscale conversion value calculated by the grayscale calculator 232 to convert the grayscales into low grayscales. At the same time, the gradation of the pixels of the even-numbered frame is shifted to the high gradation conversion value calculated by the gradation calculator 232, converted into high gradation, and output to the second gradation converter 240. Here, the first gray level converter 233 rapidly converts the grays of the pixels of the odd frame to low grays through a single transition, and also converts the grays of the pixels of the even-numbered frames to high grays through a single transition. Convert sharply For example, when the gray value of the pixel of the inputted odd frame is '50 gray 'and the calculated low gray conversion value is '42 gray', the first grayscale converter 233 may determine the pixel of the input odd frame. Sharply converts gradation to 42 gradations In addition, when the gray value of the pixel of the even-numbered frame is '50 gray 'and the calculated high gray level conversion value is '58 -gradation', the first gray level converter 233 adjusts the gray level of the pixel of the input even-numbered frame. Rapidly convert to 58 gradations.

The gray level conversion method of the first gray level conversion unit 233 will be described with reference to FIG. 4A. The first gray level conversion unit 233 calculates the gray level value 'DG' of the pixel of the inputted odd frame. The value 'LG' is rapidly converted, and at the same time, the gray level value 'DG' of the pixel of the even-numbered frame input is rapidly converted into the calculated high gray level conversion value 'HG'.

The second grayscale converter 234 shifts the grayscales of pixels of the odd frame among the same frames continuously input within a predetermined time period from low to high grayscale and outputs the grayscale converter 240 to the second grayscale converter 240. The gray level is rapidly converted from the low gray level conversion value calculated by (232) to the gray level values of the pixels of the odd frame. At the same time, the second grayscale converter 234 shifts the grayscales of pixels of the even-numbered frame from the high grayscale to the low grayscale and outputs the grayscale converter 240 to the second grayscale converter 240. The gray level is rapidly converted from the high gray level conversion value to the gray level value of the pixels of the even-numbered frame. Here, the second gray level converter 234 rapidly converts the gray level from the low gray level conversion value calculated through a single transition to the gray level values of pixels of the odd frame, and also the high gray level calculated through a single transition. The gray level is rapidly converted from the converted value to the gray level value of the pixels of the even frame. For example, if the gray level value of the pixel of the inputted odd frame is '50 gray level 'and the calculated low gray level conversion value is '42 gray level', the second gray level conversion unit 234 may use an odd number based on the calculated low gray level converted value. The gray level is rapidly converted to '42 gray level 'which is the gray level value of the pixel of the first frame. In addition, when the gray value of the pixel of the input even-numbered frame is '50 gray 'and the calculated high gray conversion value is '58 gray', the second grayscale conversion unit 234 calculates the high gray conversion value '58 gray '. The gray level is rapidly converted into '50 gray levels', which are gray level values of the pixels of the even-th frame.

The gray scale conversion method of the second gray scale converter 234 will be described with reference to FIG. 4B. The second gray scale converter 234 is a gray scale value of the pixel of the odd frame in the calculated low gray scale conversion value 'LG'. The gray level is rapidly converted to 'DG', and the gray level is rapidly converted from the calculated high gray level conversion value 'HG' to 'DG', which is the gray level value of the pixel of the even frame.

FIG. 9 is a configuration diagram of the second gradation converter in FIG. 3. However, among the terms described below, the detected grayscale value is a grayscale value of pixels of the same frames input, and the calculated low grayscale converted value is a grayscale detected as the grayscale value calculated by the first grayscale converter 230. The gradation value to be converted to a low gradation value, and the calculated high gradation conversion value is a gradation value to be converted into a high gradation value detected as the gradation value calculated by the first gradation converter 230. .

Referring to FIG. 9, the second gray scale converter 240 calculates a difference value between the gray scale value detected by the first gray scale converter 230 and the calculated low gray scale conversion value or high gray scale conversion value, and then the difference value. And a transition step calculation unit 241 for calculating a unit transition value by using a predetermined number of transitions, and a step transition value calculated by shifting the gray levels of pixels of the odd-numbered video frame by unit transition values calculated over a predetermined number of transition times. A video tone conversion unit 242 for converting up to a low gray level conversion value and converting the gray levels of pixels of the even-th video frame by a unit transition value calculated over a predetermined number of transitions to a high gray level conversion value calculated; The calculated low gray level conversion value is shifted by the unit transition value calculated over a predetermined number of transitions, and converted into the gray level values of the pixels of the odd-numbered still image frame. Be provided with a still image of the gradation conversion section (243) for each transition was calculated as a value converted to the unit of transition gradation values of pixels of the solid-th still image frames over a number of transitions.

When the gray scale is converted by the first gray scale converter 230 and the same programs are continuously input, the transition stage calculating unit 241 detects the gray scale value detected by the first gray scale converter 230 and the calculated low gray scale converted value. After calculating the difference value of the high gradation conversion value, the difference value calculated to calculate the unit transition value is divided by a predetermined number of transitions, and the quotient is calculated as the unit transition value, and the moving image gradation converter 242 and the still image gradation are calculated. Output to the converter 243. For example, when the gray value detected by the first gray converter 230 is '50 gray ', the calculated low gray converted value is '42 gray', and the calculated high gray converted value is '58 gray ', The step calculator 241 calculates a difference value '8 gradation' between the detected gray value '50 gradation 'and the calculated low gradation conversion value '42 gradation' or the high gradation conversion value '50 gradation '. When the predetermined number of transition stages is set to '8', the transition stage calculating unit 241 divides the calculated difference value '8 gradations' by the predetermined transition number '8' and unit the share '1 gradation'. Calculate by value.

When the video notification signal '1' is input from the frame discriminator 220, the video grayscale conversion unit 242 transitions the grayscales of pixels of the odd video frame by a unit transition value calculated over a predetermined number of transition times. It converts the low gradation conversion value and converts the gradations of pixels of the even-th video frame by the unit transition value calculated over a predetermined number of transitions to the high gradation conversion value. The grays of the pixels of the frame are alternately shifted by the unit transition value calculated over a predetermined number of transitions, and the number of transitions is counted for each grayscale transition.

That is, the video grayscale conversion unit 242 shifts the gray level of the pixels of the odd-numbered video frame by one unit transition value to low gray level, counts the number of transition times, and then converts the gray level of the pixels of the even-numbered video frame to high gray level. Transition one time by the unit transition value and count the number of transition times. After the grays of the pixels of the odd and even video frames are sequentially shifted once, the video grayscale conversion unit 242 once again transitions the grays of the pixels of the odd video frames by a unit transition value to low gray scale. After counting the number of transitions, the gray level of the pixels of the even-th video frame is shifted by a unit transition value once in a high gray level, and the number of transition times is counted. As described above, the transition process of low and high gradations is alternately and continuously performed, the video gradation converter 242 converts the gradations of pixels of the odd video frame to the calculated low gradation conversion value and simultaneously The gradation of the pixels is converted to the calculated high gradation conversion value. Here, the video grayscale conversion unit 242 counts the number of transitions each time the gray level of pixels of the odd-numbered video frame is shifted to the low gray level by the unit transition value, and the gray level of the pixels of the even-th video frame is increased by the unit transition value. Each time a transition is made with a high gradation, the number of transitions is counted, and a comparison is made between the counted transitions and a predetermined number of transitions. As a result of the comparison, when the number of transitions for the odd-numbered video frame is the same, the video grayscale conversion unit 242 determines that the gray-level value of the pixels of the odd-numbered frame is changed to the calculated low gray-scale conversion value and stops the grayscale transition. As a result of the comparison, when the number of transitions for the even-th video frame is the same, the video grayscale conversion unit 242 determines that the gray-scale value of the pixels of the even-numbered frame is changed to the calculated high-grayscale conversion value and stops the grayscale transition. When the gray level conversion of the pixels of the odd and even frames is completed through the linear transition steps, the video gray level conversion unit 242 may perform the linear and even numbered video frames having the linear gray level converted within a predetermined time. Continuously output to the frame output stage.

For example, the gradation value detected by the first gradation converter 230 is 50 gradations, the calculated low gradation conversion value is 42 gradations, and the calculated high gradation conversion value is 58 gradations. When the transition number of times is set to '8 times' and the calculated unit transition value is '1 gradation', a process of converting the gradation values of the pixels of the video frame will be described as an example.

The video gray scale conversion unit 242 linearly reduces the 50 gray levels of the pixels of the odd-numbered video frame by the calculated unit transition value '1 gray scale' over a predetermined number of transition times '8 times'. Low gradation calculated by converting to 42 gradations and linearly increasing the 50 gradations of pixels of the even-th video frame by a calculated unit transition value of 1 gradation over a predetermined number of transition times of 8 gradations. Converts the converted value to '58 gradation 'and outputs it to the frame output terminal. Here, the video grayscale conversion unit 242 counts the number of transitions each time 50 grays of the pixels of the odd video frame are reduced by the unit transition value '1 gray', and the 50 grays of the pixels of the even video frame are united. Each time the number of transitions is increased by one gradation, the number of transitions is counted, and a comparison is made whether the counted number of transitions is equal to a predetermined transition number of 'eight times'. As a result of the comparison, when the number of transitions for the radix-th video frame is 'eight times', the video grayscale conversion unit 242 determines that 50 grays of the pixels of the radix-th video frame are changed to the calculated low grayscale conversion value '42th gray'. Stop the tone transition. As a result of the comparison, when the number of transitions for the even-th video frame is' eight times', the video gradation converter 242 determines that 50 gradations of pixels of the even-most video frame are changed to the calculated high gradation value '58 gradations'. Stop the tone transition. In this case, the grayscale conversion of the video grayscale conversion unit 242 will be described with reference to FIG. 5A. The video grayscale conversion unit 242 calculates the unit grayscale value 'DG' of the pixel of the inputted odd video frame. Linearly decreases by '1 gradation' over a predetermined number of transition times '8 times' and converts it to the low gradation conversion value 'LG' that is calculated, and simultaneously converts the gradation value 'DG' of the pixel of the even-th input video frame. The calculated unit transition value '1 gradation' is linearly increased over a predetermined number of transition times '8 times' and converted into the calculated high gradation conversion value 'HG'.

When the still image notification signal '0' is input from the frame discriminator 220, the still image gray scale conversion unit 243 shifts the calculated low gray scale conversion value by the unit transition value calculated over a predetermined number of transition times. Converting the gray level value of the pixels of the still image frame, and simultaneously converting the calculated high gray level conversion value by the unit transition value calculated over a predetermined number of transition times to the gray level value of the pixels of the even-numbered still image frame. The low gray conversion value and the high gray conversion value calculated are alternately shifted by the unit transition value calculated over a predetermined number of transitions, and the number of transitions is counted for each gray level transition.

That is, the still image gradation converting unit 243 increases the calculated low gradation conversion value once by a unit transition value in the direction of the gradation value of the pixels of the odd-numbered still image frame, counts the number of transitions, and then calculates the calculated high gradation The converted value is decreased once by the unit transition value in the direction of the gradation value of the pixels of the even-numbered still image frame, and the number of transitions is counted. After the calculated low gray level conversion value and the high gray level conversion value are sequentially shifted once, the still image gray level conversion unit 243 once again converts the calculated low gray level conversion value in the direction of the gray level value of the pixels of the odd-numbered still image frame. After increasing the unit transition value once and counting the number of transition times, the calculated high gradation conversion value is decreased once by the unit transition value in the direction of the gradation value of the pixels of the even-numbered still image frame and counted. As described above, by successively performing a transition process between low and high gradations, the still image gradation converter 243 converts the calculated low gradation conversion value into gradations of pixels of the odd-numbered still image frame and simultaneously calculates the high gradation. The converted value is converted into the gray level of the pixels of the even-numbered still image frame. Here, the still image gradation conversion unit 243 counts the number of transitions each time the calculated low gradation conversion value is increased by the unit transition value in the gradation direction of the pixels of the odd-numbered still image frame, and the calculated high gradation conversion value is obtained. The number of transitions is counted each time by decreasing the unit transition value in the gradation direction of the pixels of the even-numbered still image frame, and a comparison is made between the counted transition number and the predetermined transition number. When the number of transitions for the low gray scale conversion value calculated as the result of the comparison is the same, the still image gray scale conversion unit 243 determines that the calculated low gray scale conversion value is changed to the gray scale values of the pixels of the odd-numbered still image frame, and then performs the gray level transition. Stop. If the number of transitions to the calculated high gradation value is the same, the still image gradation converter 243 determines that the calculated high gradation value is changed to the gradation value of the pixels of the even-numbered still image frame, and then performs gradation transition. Stop. When the gray level conversion value and the high gray level conversion value calculated as described above are completed through the linear transition steps, the still image gray level conversion unit 243 converts the odd-numbered and even-numbered still image frames in which the gray level is linearly converted. Outputs to the frame output stage continuously within a certain time.

For example, the gradation value detected by the first gradation converter 230 is 50 gradations, the calculated low gradation conversion value is 42 gradations, and the calculated high gradation conversion value is 58 gradations. When the transition number of times is set to '8 times' and the calculated unit transition value is '1 gradation', a process of converting the gradation values of the pixels of the video frame will be described as an example.

The still image gradation converting unit 243 linearly increases the calculated low gradation conversion value '42 gradations' by the calculated unit transition value '1 gradation' over a predetermined number of transition times' 8 times', thereby increasing the odd-numbered still image. It converts to 50 gradations of the pixels of the frame, and at the same time, the high gradation conversion value '58 gradations' is linearly decreased by the calculated unit transition value '1 gradation' over a predetermined number of transition times' 8 times'. The pixels of the first video frame are converted to 50 gray levels and output to the frame output terminal. Here, the still image gradation converting unit 243 counts the number of transitions each time the calculated low gradation conversion value '42 gradations' is increased by the unit transition value '1 gradation', and the calculated high gradation conversion value '58 gradations Every time 'is decreased by the unit transition value' 1 gradation ', the number of transitions is counted, and a comparison is made whether the counted transition number is equal to the predetermined transition number' 8 times'. When the number of transitions for the low gray scale conversion value calculated as the result of the comparison is' eight times', the still image gray scale conversion unit 243 determines that the low gray scale conversion value '42 gray scales' is calculated as 50 gray scales of the pixels of the odd-numbered still image frame. Determination of change is made, and the grayscale transition is stopped. When the number of transitions to the high gray scale conversion value calculated as the result of the comparison is' eight times', the still image gray scale conversion unit 243 determines that the high gray scale conversion value '58 gray scale 'is calculated as 50 gray levels of the pixels of the even-numbered still image frame. Determination of change is made, and the grayscale transition is stopped. In this case, the gray level conversion of the still image gray level conversion unit 243 will be described with reference to FIG. 5B, and the still image gray level conversion unit 243 calculates the calculated low gray level conversion value 'LG'. 'Increasing linearly by' 8 times' by a predetermined number of transitions, converting to the gradation value 'DG' of the pixel of the radix-th still image frame, and simultaneously calculating the calculated high gradation conversion value 'HG' The value '1 gradation' is linearly reduced over a predetermined number of transition times '8 times' and converted into the gradation value 'DG' of the pixel of the even-numbered frame.

The frame output terminal is connected to an input terminal of the timing controller 190 of the liquid crystal display device 100. Therefore, the frame output from the second gray scale converter 240 is input to the timing controller 190. Accordingly, the timing controller 190 drives the liquid crystal display panel 110 at a frame frequency of 60 Hz to a frame frequency of 120 Hz and converted through linear grayscale transition steps.

As described above, the present invention multiplies the frame frequency of 60 Hz through the frequency converter 210 to the frame frequency of 120 Hz, and then converts the gray values of pixels of the same frames continuously driven within a predetermined time through linear gray scale transition steps. By driving the converted frames to the liquid crystal display panel 110, the screen may be prevented from flashing due to the sudden gray level conversion.

A driving process of the liquid crystal display device of the present invention having the configuration and function as described above will be described with reference to a flowchart.

10 is a flowchart illustrating a method of driving a liquid crystal display according to an exemplary embodiment of the present invention. However, a process of processing the current frame while the previous frame is stored in the frame discriminator 220 will be described.

Referring to FIG. 10, when a current frame output from a scaler (not shown) included in a system such as a television receiver or a computer monitor is input through a frame input terminal (S110), the frequency converter 210 temporarily stores the current frame. After this, the first frame frequency is doubled to the second frame frequency to generate the same frames continuously driven within a predetermined time (S120). In addition, the first gray scale converter 230 generates the gray level values of the pixels of the odd and even frames generated by the frequency converter 210 so as to be driven at the second frame frequency, as shown in FIGS. 4A and 4B. Transition through the transition (S130).

At this time, the frame discriminator 220 determines whether the current frame is a still image or a video frame by using a previously stored previous frame and generates a still image notification signal or a video notification signal according to the determination result (S140).

When the video notification signal '1' is generated, the second grayscale converter 240 adjusts the grayscale values of the pixels of the odd and even video frames converted by the first grayscale converter 220 in response to the video notification signal '1'. Is transformed through the linear transition steps as shown in Figure 5a (S150).

When the still image notification signal '0' is generated, the second gray scale converter 240 may display pixels of the odd and even video frames converted by the first gray scale converter 230 in response to the still image notification signal '0'. The grayscale value is converted through linear transition steps as shown in FIG. 5B (S160).

FIG. 11 is a detailed flowchart illustrating a frame frequency conversion process of FIG. 10.

Referring to FIG. 11, when the current frame is input through the frame input terminal, the frequency converter 210 temporarily stores the current frame (S121). In this state, the frequency converter 210 continuously reads the current frame stored twice in a predetermined time in order to double the first frame frequency to the second frame frequency (S122), and performs the same frames continuously driven within the predetermined time. It generates (S123).

FIG. 12 is a detailed flowchart illustrating a sudden gray scale conversion process of FIG. 10.

Referring to FIG. 12, when frames generated by the frequency converter 210 are continuously input, the first grayscale converter 230 detects grayscale values of pixels of the same frames that are input (S131).

After the gray scale value is detected, the first gray scale converter 230 subtracts the predetermined gray scale value from the detected gray scale value, calculates a low gray scale conversion value to be converted, and simultaneously converts the predetermined gray scale value to the detected gray scale value. The high gray scale conversion value to be converted is calculated by adding the value (S132).

Subsequently, the first grayscale converter 230 transitions the grayscales of the pixels of the odd frame among the inputted frames to the low grayscale conversion value at once and converts the grayscales into low grayscales. The gray scales of these fields are shifted to the calculated high gray scale conversion value at one time, converted to high gray scale, and output to the second gray scale converter 240 (S133).

The first gradation converter 230 transitions the calculated low gradation value at once, converts it into gradation values of pixels of the odd frame, and outputs the gradation value to the second gradation converter 240. The converted value is shifted at one time, converted to the gray value of the pixels of the even-numbered frame, and output to the second gray scale converter 240 (S134).

FIG. 13 is a flowchart illustrating a process of generating a notification signal in FIG. 10.

Referring to FIG. 13, when the current frame is input through the frame input terminal in a state in which the previous frame is stored, the frame discriminator 220 reads out the stored previous frame (S141), and the gray level of the pixels corresponding to the previous frame and the current frame is read. After calculating the difference values (S142), all the calculated grayscale difference values are added to obtain an addition value (S143).

Subsequently, the frame discriminator 220 compares the addition value with the predetermined reference gradation value and determines whether the addition value is smaller than the predetermined reference gradation value (S144). As a result of the determination, if the addition value is smaller than the predetermined reference gradation value, the frame discriminator 220 determines that the current frame is a still image frame and generates a still image notification signal '0' (S145). As a result of the determination, if the addition value is larger than the predetermined reference gray value, the frame discriminator 220 determines that the current frame is a video frame and generates a video notification signal '1' (S146).

FIG. 14A is a flowchart illustrating a linear gray scale conversion process of FIG. 10 in detail, and illustrates a gray scale conversion process of a video frame.

Referring to FIG. 14A, when the video frames converted by the first grayscale converter 240 are continuously input within a predetermined time and the video notification signal '1' is input from the frame discriminator 220, the second grayscale converter 240 calculates a difference value between the gradation value detected by the first gradation converter 230 and the calculated low gradation conversion value or high gradation conversion value (S151), and then calculates the calculated difference value at a predetermined number of transition times. By dividing, the quotient is calculated as a unit transition value (S152).

After the unit transition value is calculated, the second gray scale converter 240 alternately shifts the gray levels of the pixels of the odd and even video frames over a predetermined number of transitions, and gradually shifts the gray levels. Each time the number of transitions is counted (S153), it is determined whether the counted transition number and the predetermined transition number are the same (S154).

As a result of the determination, when the number of transitions is the same, the second grayscale converter 240 determines that the grayscale value of the pixels of the odd frame is changed to the calculated low grayscale conversion value and stops the grayscale transition, and the grayscale of the pixels of the even-numbered frame. The gray scale transition is stopped by determining that the value is changed to the calculated high gray scale conversion value (S155).

If it is determined that the number of transitions is not the same, the second gray scale converter 240 continuously shifts the gray levels until the counted transition number and the predetermined transition number become the same.

FIG. 14B is a flowchart illustrating a linear gray scale conversion process of FIG. 10 in detail, and illustrates a gray scale conversion process of a still image frame.

Referring to FIG. 14B, when the grayscale-converted video frames converted by the first grayscale converter 240 are continuously input within a predetermined time and a still image notification signal '0' is input from the frame discriminator 220, the second grayscale The converter 240 calculates a difference value between the gradation value detected by the first gradation converter 230 and the calculated low gradation conversion value or high gradation conversion value (S161), and then calculates the calculated difference value by a predetermined number of transition times. The quotient is calculated as a unit transition value by dividing by (S162).

After the unit transition value is calculated, the second gray scale converter 240 alternately shifts the calculated low gray level conversion value and the high gray level conversion value by the unit transition value calculated over a predetermined number of transition times as the detected gray level value. At the same time, the number of transitions is counted for each grayscale transition (S163), and it is determined whether the counted transition number and the predetermined transition number are the same (S164).

As a result of the determination, if the number of transitions is the same, the second gray scale converter 240 determines that the calculated low gray scale conversion value is changed to the gray scale values of the pixels of the odd frame, stops the gray scale transition, and the calculated high gray scale conversion value The gray scale transition is stopped by determining that the gray value of the pixels of the even-numbered frame is changed (S165).

If it is determined that the number of transitions is not the same, the second gray scale converter 240 continuously shifts the gray levels until the counted transition number and the predetermined transition number become the same.

As described above, according to the present invention, in a liquid crystal display device that doubles the frame frequency, the grayscale value of a still image or video frame is linearly converted, and the same frames having the linearly converted grayscale value are continuously converted within a predetermined time. By driving, it is possible to prevent the screen flickering caused by abrupt gradation conversion.

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 (33)

Frequency converting means for receiving the frame and converting the frame frequency to continuously output the same frames within a predetermined time; Frame determination means for determining whether the input frame is a still image or a moving image frame and outputting a still image notification signal or a moving image notification signal according to a determination result; First gray level converting means for converting the gray level values of pixels of the same frames continuously input within the predetermined time from the frequency converting means through one gray level transition; And Second gray level converting means for converting a gray level value of pixels of the same frames input from the first gray level converting means through linear grayscale transition steps in response to the still image notification signal or a video notification signal; Driving device of the liquid crystal display device comprising a. The method of claim 1, The frequency converting means, A storage unit for temporarily storing the input frame; And A frequency conversion controller for temporarily storing an input frame in the storage unit, double-speeding a first frame frequency to a second frame frequency, and continuously reading and outputting the frame in the storage unit within a predetermined time; Driving device of the liquid crystal display device comprising a. The method of claim 2, Wherein the first frame frequency is 60 Hz, and the second frame frequency is 120 Hz. The method of claim 1, The frame discrimination means, A storage unit for storing one or more previous frames of the input current frame; A frame discrimination controller configured to store the previous frame in the storage unit, and read out the previous frame as the current frame is input to control determination of an image state of the current frame; A system value calculation unit for calculating gray level difference values of corresponding pixels of the previous frame and the current frame under the control of the frame determination unit; An adder for adding the calculated gray level differences according to the control of the frame discrimination controller; And Under the control of the frame discriminating controller, the second gray level converting means generates the still image notification signal or the video notification signal according to a comparison result by comparing the addition value added by the adding unit with a predetermined reference gray value. Notification signal generator for outputting Driving device of the liquid crystal display device comprising a. 5. The method of claim 4, The notification signal generator, when the addition value is smaller than the predetermined reference gradation value, judging the current frame as a still image frame to generate the still image notification signal and outputs to the second tone conversion means. A drive device for a liquid crystal display device. 5. The method of claim 4, The notification signal generation unit, if the addition value is greater than the predetermined reference gray value, the liquid crystal display, characterized in that the current frame is determined to be a video frame to generate the video notification signal and output to the second gray scale conversion means. Drive of the device. The method according to any one of claims 4 to 6, And the gradation value calculating unit calculates gradation difference values between corresponding pixels of the current frame and one previous frame. The method according to any one of claims 4 to 6, And the gray level value calculating unit calculates gray level differences between the current frame and corresponding pixels of at least two or more previous frames. The method of claim 1, The first gradation conversion means, A gray scale detector for detecting gray scale values of pixels of the same frames continuously input from the frequency converting means within a predetermined time; A gray scale calculator for calculating a low gray scale conversion value and a high gray scale converted value to be converted by using the gray scale value detected by the gray scale detector and a predetermined reference gray scale value; A first gradation conversion unit for converting gradations of pixels of the odd and even frames among the same input frames to the calculated low gradation conversion value and the high gradation conversion value at one time; And A second gray level conversion unit for converting the gray level at once from the calculated low gray level conversion value and the high gray level conversion value to the gray level values of the pixels of the odd and even frames, respectively; Driving device of the liquid crystal display device comprising a. The method of claim 9, The gradation calculator calculates the low gradation value by subtracting the predetermined reference gradation value from the detected gradation value, and simultaneously calculates the high gradation value by adding the predetermined reference gradation value to the detected gradation value. A drive device for a liquid crystal display device, characterized in that. The method of claim 9, The first gray scale conversion unit, The gray level of the pixels of the odd-numbered frame is shifted to the calculated low gray scale conversion value at once, and the gray level of the pixels of the even-numbered frame is shifted to the calculated high gray scale conversion value at once. A drive device for a liquid crystal display device, characterized by converting to high gradation. 12. The method according to any one of claims 9 to 11, The second gray scale conversion unit, Convert the gradation at once from the calculated low gradation conversion value to the gradation value of the pixels of the odd frame and simultaneously convert the gradation at once from the calculated high gradation conversion value to the gradation value of the pixels of the even frame Driving device for a liquid crystal display device characterized in that. The method of claim 9, The second gray scale conversion means, A transition step calculation unit for calculating a difference value between the detected gray value and the calculated low gray level conversion value or the high gray level conversion value, and calculating a unit transition value using the difference value and a predetermined number of transition times; The gray level of the pixels of the odd-th video frame is shifted by the calculated unit transition value over the predetermined number of transitions, and converted into the calculated low gray level conversion value, and the gray level of the pixels of the even-th video frame is converted to the predetermined number. A video grayscale conversion unit for shifting the calculated unit transition value by the number of transitions and converting the calculated high grayscale conversion value to the calculated high gray scale conversion value; And The calculated low gray scale conversion value is shifted by the calculated unit transition value over the predetermined number of transitions, and is converted into gray scale values of pixels of the odd-numbered still image frame, and the calculated high gray scale conversion value is converted into the predetermined high gray scale conversion value. A still image gradation conversion unit for shifting the calculated unit transition value over the number of transitions and converting the calculated unit transition value into gradation values of pixels of the even-numbered still image frame Driving device of the liquid crystal display device comprising a. The method of claim 13, The transition step calculating unit divides the calculated difference value by the predetermined number of transitions, calculates the quotient as the unit transition value, and outputs the gradation conversion unit and the still image gradation conversion unit. Drive system. 15. The method of claim 14, The video grayscale conversion unit alternately shifts the grays of the pixels of the odd and even video frames by the calculated unit transition value over the predetermined number of transitions, and counts the number of transitions every grayscale transition. A drive device for a liquid crystal display device. 16. The method of claim 15, When the gray level of the pixels of the radix video frame is converted into the calculated low gray level conversion value, the video gray level converting unit converts the gray levels of the pixels of the radix video frame if the number of transitions and the predetermined number of transitions are the same. And the gray scale transition is stopped by determining that the calculated low gray scale conversion value has been converted. 16. The method of claim 15, The video grayscale conversion unit converts the grayscales of the pixels of the even-th video frame to the calculated high grayscale conversion value, and if the counted transition number is equal to the predetermined transition number, the grayscales of the pixels of the even-numbered video frame are equal. And the gray scale transition is stopped by determining that the high gray scale conversion value is converted to the calculated high gray scale conversion value. 15. The method of claim 14, The still image gradation converting unit alternately shifts the calculated low gradation conversion value and the high gradation conversion value by the calculated unit transition value over the predetermined number of transitions, and counts the number of transitions for each gradation transition. A drive device for a liquid crystal display device, characterized in that. The method of claim 18, The still image gradation converting unit converts the calculated low gradation conversion value into gradation values of pixels of the odd-numbered still image frame, and the calculated low gradation conversion value is equal to the counted transition number. And the grayscale transition is stopped by determining that the pixels of the odd-numbered still image frame are converted to grayscale values. The method of claim 18, The still image gradation converting unit converts the calculated high gradation conversion value into gradation values of the pixels of the even-numbered still image frame, and the calculated high gradation conversion value is equal to the counted transition number. And the grayscale transition is stopped by determining that the grayscale value of the pixels of the even-th still image frame is converted. When the current frame is input while the previous frame is stored, converting the first frame frequency to the second frame frequency to generate identical frames continuously driven within a predetermined time; Translating and converting the grayscale values of the pixels of the generated frames to be driven at the second frame frequency at one time; Determining whether the current frame is a still image or a video frame using the previous frame and generating a still image notification signal or a video notification signal according to a determination result; And In response to the video notification signal or the still image notification signal, converting the gray level value of pixels of the frames whose gray level is converted in the gray level conversion step through linear gray level transition steps; Method of driving a liquid crystal display device comprising a. 22. The method of claim 21, The frame generation step, Temporarily storing the current frame when the current frame is input; And Reading out the stored current frame twice in a predetermined time so as to double the first frame frequency to the second frame frequency to generate the same still image frames or video frames continuously driven within a predetermined time; Method of driving a liquid crystal display device comprising a. Claim 23 has been abandoned due to the setting registration fee. 23. The method of claim 22, Wherein the first frame frequency is 60 Hz, and the second frame frequency is 120 Hz. 22. The method of claim 21, The step of translating and converting the gray scale values at once, Detecting a gray value of the generated pixels of the same frames; Calculate a low gradation value to be converted by subtracting a predetermined reference gradation value from the detected gradation value, and simultaneously calculate a high gradation conversion value to be converted by adding the predetermined reference gradation value to the detected gradation value. Doing; The high gray scale conversion value calculated by shifting the gray scales of pixels of the odd frame among the generated identical frames at once and converting the gray scales of the pixels of the even-numbered frame at a time. Converting to; And Converting the calculated low gray level conversion value at once to convert the calculated low gray level conversion value to the gray level value of the pixels of the odd frame, and converting the calculated high gray level conversion value at a time to convert the gray level value of the pixels of the even frame step Method of driving a liquid crystal display device comprising a. Claim 25 is abandoned in setting registration fee. The notification signal generating step, Reading the stored previous frame when the current frame is input; Calculating gray level differences between the read previous frame and corresponding pixels of the current frame; Adding all the calculated gray level differences to obtain an added value; Comparing the added value with a predetermined reference gray value to determine whether the added value is smaller than the predetermined reference gray value; Determining that the current frame is a still image frame and generating the still image notification signal when the addition value is smaller than the predetermined reference gray value as a result of the determination; And Determining that the current frame is a video frame when the addition value is greater than the predetermined reference gray scale value, and generating the video notification signal. Method of driving a liquid crystal display device comprising a. Claim 26 is abandoned in setting registration fee. 25. The method of claim 24, The step of converting the grayscale value through linear grayscale transition steps, Calculating a difference value between the detected gray level value and the calculated low gray level conversion value or the high gray level conversion value; Calculating a unit transition value using the calculated difference value and a predetermined number of transitions; The gray level of the pixels of the odd-th video frame is shifted by the calculated unit transition value over the predetermined number of transitions, and converted into the calculated low gray level conversion value, and the gray level of the pixels of the even-th video frame is converted to the predetermined number. Converting the calculated unit transition value by the calculated unit transition value over the number of transitions and converting the calculated high gradation conversion value; And The calculated low gray scale conversion value is shifted by the calculated unit transition value over the predetermined number of transitions, and is converted into gray scale values of pixels of the odd-numbered still image frame, and the calculated high gray scale conversion value is converted into the predetermined high gray scale conversion value. Converting the calculated unit transition values by the number of transitions and converting them into gradation values of pixels of the even-numbered still image frame Method of driving a liquid crystal display device comprising a. Claim 27 was abandoned upon payment of a registration fee. 27. The method of claim 26, And in the unit transition value calculating step, dividing the calculated difference value by the predetermined number of transition times and calculating the quotient as the unit transition value. Claim 28 has been abandoned due to the set registration fee. 27. The method of claim 26, In the step of converting the calculated low tone conversion value and high tone conversion value, Claim 29 has been abandoned due to the setting registration fee. 29. The method of claim 28, When the gray level of the pixels of the odd video frame is converted into the calculated low gray level conversion value, if the counted transition number and the predetermined number of transitions are the same, the gray level of the pixels of the odd video frame is calculated. And a gray level transition is stopped by determining that the converted value has been converted. Claim 30 has been abandoned due to the set registration fee. 29. The method of claim 28, When converting the gradation of the pixels of the even-th video frame into the calculated high gradation conversion value, if the counted transition number is equal to the predetermined transition number, the gradation of the pixels of the even-th video frame is calculated. And a gray level transition is stopped by determining that the converted value has been converted. Claim 31 has been abandoned due to the setting registration fee. 27. The method of claim 26, Wherein the calculated low gray level conversion value and the high gray level conversion value are alternately shifted by the calculated unit transition value over the predetermined number of transitions, and the number of transitions is counted for each gray level transition. Method of driving the device. Claim 32 is abandoned due to the set registration fee. 32. The method of claim 31, When the calculated low gray scale conversion value is converted to gray values of the pixels of the odd-numbered still image frame, if the counted transition number and the predetermined number of transitions are the same, the calculated low gray scale conversion value is the odd-numbered still image. And a gray level transition is stopped by determining that the pixels are converted to gray values of the frame. Claim 33 was abandoned upon payment of a registration fee. 32. The method of claim 31, When the calculated high gradation conversion value is converted to the gradation value of the pixels of the even-numbered still image frame, if the counted transition number and the predetermined transition number are the same, the calculated high gradation conversion value is the even-numbered still image. And a gray level transition is stopped by determining that the pixels are converted to gray values of the frame.

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