KR20060135105A - Display device and driving method thereof - Google Patents

Abstract

A display device and a driving method thereof are provided to reduce current consumption of the display device by displaying images while changing inversion schemes according to predetermined patterns. A display device includes a display panel(500), a timing controller(100), a data driver(200), and a scan driver(300). The timing controller outputs a second data signal, a data control signal, and a scan control signal in response to a first data signal and an external control signal. The timing controller compares the first data signal with a third data signal corresponding to a predetermined pattern of respective frames and outputs an inversion selection signal. The data driver receives the second data signal, the data control signal, and the inversion selection signal and controls the display panel. The data driver outputs a data driving signal to the display panel based on the inversion selection signal. The scan driver receives the scan control signal and outputs a scan driving signal to the display panel.

Description

Display device and driving method thereof {DISPLAY DEVICE AND DRIVING METHOD THEREOF}

1 is a block diagram illustrating a display device according to an exemplary embodiment of the present invention.

FIG. 2 is a block diagram illustrating a timing controller of the display device of FIG. 1.

3 is a plan view conceptually illustrating a first image displayed on the display device of FIG. 1.

4A and 4B are waveform diagrams of data driving signals applied to display the first image of FIG. 3.

5 is a plan view conceptually illustrating a second image displayed on the display device of FIG. 1.

6A and 6B are waveform diagrams of data driving signals applied to display the second image of FIG. 5.

7 is a flowchart illustrating a method of driving a display device according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: timing controller 110: first memory

120: data signal generator 130: second memory

140: pattern storage memory 150: comparator

160: inverted signal generator 170: control signal generator

200: data driver 300: scan driver

400: driving voltage generator 500: display panel

The present invention relates to a display device and a driving method thereof, and more particularly, to a display device and a driving method thereof for reducing power consumption.

In general, a liquid crystal display (LCD) is a liquid crystal display panel (LCD) for displaying an image by the light transmittance of the liquid crystal (liquid crystal), and is electrically connected to the liquid crystal display panel to display an image And a driving unit for applying a driving signal to the liquid crystal display panel and a back-light assembly for providing light to the liquid crystal display panel.

The liquid crystal display panel includes an array substrate having a plurality of switching elements formed thereon, a color filter substrate disposed to face the array substrate and having a plurality of color filters formed therein, the array substrate and the color. It consists of a liquid crystal layer interposed between filter substrates.

The driving unit receives an external data signal and an external control signal from an external graphic controller to generate an image data signal, a data control signal and a scan control signal, and the liquid crystal display panel receives the image data signal and a data control signal. And a data driver for applying a scan driving signal to the liquid crystal display panel by receiving the scan control signal.

In general, the current consumption of the liquid crystal display is determined by the image data signal and the data driving signal. In particular, when the data drive signal has a binary value such as 101010, the data drive signal swings at a high frequency.

However, when the data driving signal swings at a high frequency, the display device has a problem in that a high current consumption is generated.

Accordingly, an object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a display device for reducing current consumption by changing an inversion scheme according to a predetermined pattern.

Another object of the present invention is to provide a method of driving the display device.

In order to achieve the above object of the present invention, the display device includes a display panel, a timing controller, a data driver, and a scan driver. The display panel displays an image. The timing controller outputs a second data signal, a data control signal, and a scan control signal in response to a first data signal and an external control signal applied from the outside, and corresponds to the predetermined pattern for each frame. The inverted selection signal is output in comparison with the third data signal. The data driver receives the second data signal, a data control signal, and an inversion selection signal to control the display panel, and outputs a data driving signal whose inversion scheme is changed based on the inversion selection signal to the display panel. The scan driver receives the scan control signal and outputs a scan driving signal to the display panel.

According to another aspect of the present invention, there is provided a method of driving a display device, the method including applying an external data signal to a display device, comparing the data signal with data information of a predetermined pattern for each frame. Outputting an inversion selection signal and driving the display device in an inversion manner determined according to the inversion selection signal.

According to such a display device and a driving method thereof, when the data signal applied from the outside has data information displaying a predetermined pattern, the current consumption can be further reduced by changing the inversion method of the display panel to display an image. .

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

<Example of Display Device>

1 is a block diagram illustrating a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the display device includes an timing controller 100, a data driver 200, a scan driver 300, a driving voltage generator 400, and a display panel 500 to display an image.

The timing controller 100 receives an image signal which is a digital signal from an external graphic controller (not shown). The timing controller 100 controls the image signal according to a timing to provide the image driver 200 with an image data signal DATA2, a data control signal, and an inversion selection signal REV, and the scan driver 300. ) Provides a scan control signal and provides a voltage driving signal Pcon to the driving voltage generator 400.

The image signal provided from the graphic controller includes, for example, a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock MCK, a data enable signal DE, an external data signal DATA1, and the like. There is this.

The vertical synchronization signal Vsync indicates the start or end of each field. The horizontal synchronization signal Hsync indicates the start or end of a row line in the display panel 500. The main clock MCK is a signal for synchronizing the external data signal DATA1. The data enable signal DE defines an effective range of the external data signal DATA1 between the horizontal synchronization signal Hsync and the horizontal synchronization signal Hsync.

The external data signal DATA1 includes RGB image information for displaying an image. That is, the external data signal DATA1 includes a red data signal having red image data, a green data signal having green image data, and a blue data signal having blue image data.

The timing controller 100 outputs the inversion selection signal REV by comparing the external data signal DATA1 with a pattern data signal including information of a predetermined pattern for each frame. The inversion selection signal REV is a signal for determining an inversion method of the display panel 500 and is applied to the data driver 200 to control the data driver 200.

The data driver 200 receives the image data signal DATA2, the data control signal and the inversion selection signal REV generated by the timing controller 100, and receives the image data signal DATA2 from the data control signal. And an inversion selection signal REV, which is converted into the data driving signal and applied to the data lines D1, D2, ..., D2m of the display panel 500 (where m is a natural number).

The data control signal includes a data start signal STH for notifying the start of the image data signal DATA2, a data load signal Load for notifying the output of the data driving signal after the transmission of the image data signal DATA2 is completed. And a data synchronizing signal DOT for synchronizing the image data signal DATA2.

The data driver 200 receives the image data signal DATA2, which is a digital signal, as a serial and temporarily stores the image data signal DATA2 in line units. The data stored in the line unit is converted into an analog signal according to a reference color data value in order to display an image having an actual desired color, and is stored in the data lines D1, D2, ..., D2m of the display panel 500. Applied line by line. In this case, the inversion selection signal REV controls the data driver 200 to determine a predetermined inversion method, and applies the data driving signal to the display panel 500 according to the determined inversion method. do.

The scan driver 300 receives the scan control signal generated by the timing controller 100 and is controlled by the scan control signal to scan lines G1, G2,... Of the display panel 500. (Gn) is sequentially applied to the scan drive signal. (Where n is a natural number.) The scan control signal synchronizes the scan start signal (STV) and the scan drive signal indicating the start of the output of the scan drive signal. Scan clock (GCK). In this case, the scan driver 300 receives an on / off reference voltage Von / Voff that provides a reference voltage of the scan driving signal from the driving voltage generator 400.

The driving voltage generator 400 is driven by receiving power Vcc from the outside, and is controlled by receiving the voltage driving signal Pcon from the timing controller 100 to control the scan driver 300 and the display panel. A driving voltage necessary for driving 500 is output.

For example, the on / off reference voltage Von / Voff applied to the scan driver 300, the common voltage Vcom applied to the common electrode formed on the display panel 500, and the display may be applied to the driving voltage. Storage reference voltage Vst applied to the reference voltage line formed on the panel 500.

The display panel 500 includes an array substrate on which a plurality of switching elements are formed, a color filter substrate disposed to face the array substrate, and a plurality of color filters are formed, and a liquid crystal layer interposed between the array substrate and the color filter substrate. Is done. The switching elements are, for example, thin film transistors.

A plurality of data lines D1, D2,..., D2m are arranged in parallel along a first direction on the array substrate, and a plurality of scan lines G1, G2,..., Gn have a first direction. Arranged in parallel along the second vertical direction. The data lines D1, D2, ..., D2m and the scan lines G1, G2, ..., Gn cross each other to define pixel regions, and unit pixels are formed in each of the pixel regions. .

Each unit pixel includes a thin film transistor, a liquid crystal capacitor Clc, and a storage capacitor Cst, which are switching elements. Each thin film transistor includes a gate electrode, a source electrode and a drain electrode. The gate electrode is connected to the scan lines G1, G2, ..., Gn, the source electrode is connected to the data lines D1, D2, ..., D2m, and the drain electrode is the liquid crystal. It is connected to the pixel electrode which is the first electrode of the capacitor Clc.

The color filter substrate includes color filters including color pixels corresponding to each unit pixel, and a common electrode applied with the common voltage Vcom and a second electrode of the liquid crystal capacitor Clc.

The liquid crystal capacitor Clc is defined by the pixel electrode connected to the drain electrode and the common electrode applying the common voltage Vcom. In addition, the storage capacitor Cst is defined by a reference voltage line applying the storage reference voltage Vst and the pixel electrode.

In brief, a process of displaying an image by the display panel may include data driving signals generated by the data driver 200 and scan driving signals generated by the scan driver 300. , D2m) and scan lines G1, G2, ..., Gn are applied. When the data driving signal and the scan driving signal are applied to the display panel 500, an electric field is formed between the pixel electrode and the common electrode, and the electric field transmittance of the liquid crystal layer interposed between the pixel electrode and the common electrode. To display the image.

Hereinafter, the timing controller 100 will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram illustrating a timing controller of the display device of FIG. 1.

Referring to FIG. 2, the timing controller 100 includes a first memory 110, a data signal generator 120, a second memory 130, a pattern storage memory 140, a comparator 150, and an inverted signal generator. 160.

The first memory 110 receives the external data signal DATA1 and stores the received data in frame units. The first memory 110 newly stores the external data signal DATA1 currently being input and outputs the previously input external data signal DATA1 to the data signal generator 120 and the second memory. To (130).

In this case, a data signal output from the first memory 110 and applied to the data signal generator 120 is referred to as a first data signal DATA1-1, and is output from the first memory 110 so that the data signal is output from the first memory 110. The data signal applied to the second memory 130 is referred to as a second data signal DATA1-2.

The data signal generator 120 receives the first data signal DATA1-1 from the first memory 110 and rearranges the data signal generator 2 to output the image data signal DATA2. In this case, the image data signal DATA2 is a data signal that is applied to the data driver 200 to rearrange the first data signal DATA1-1 so that the image can be displayed.

The second memory 130 receives the second data signal DATA1-2 from the first memory 110 and stores the second data signal DATA1-2 in units of frames, and stores the first data signal DATA1-2 previously input. The output is applied to the comparator 150. In this case, a data signal output from the second memory 130 and applied to the comparator 150 is referred to as a third data signal DATA1-3.

The pattern storage memory 140 stores information about a predetermined pattern. The pattern storage memory 140 outputs at least one fourth data signal DATA1-4 corresponding to the information and applies it to the comparator 150.

The predetermined patterns are patterns having a large current consumption when displayed on the display panel, and patterns in which the current consumption varies according to an inversion method. For example, the predetermined patterns are patterns having a digital value having a large swing frequency, such as 101010. In this case, the fourth data signal DATA1-4 may be signals having a plurality of pieces of information corresponding to the patterns.

The comparator 150 receives the third data signal DATA1-3 from the second memory 120, and receives the fourth data signal DATA1-4 from the pattern storage memory 140.

The comparator 150 compares the third and fourth data signals DATA1-3 and DATA1-4 to determine whether the third and fourth data signals DATA1-3 and DATA1-4 are the same. To judge. Here, the third data signal DATA1-3 includes a first red data signal, a first green data signal, and a first blue data signal, and the fourth data signal DATA1-4 includes a second red data signal. , A second green data signal and a second blue data signal. In this case, the determination of identity may be performed by comparing the first and second red data signals with each other, comparing the first and second green data signals with each other, and comparing the first and second blue data signals with each other.

When the comparator 150 determines that the third and fourth data signals DATA1-3 and DATA1-4 are identical to each other, the comparator 150 outputs an inversion control signal SEL to the inversion signal generator 160. . Preferably, the comparator 150 outputs the inversion control signal SEL by synchronizing on a frame basis.

In this case, since the fourth data signal DATA1-4 may include information about a plurality of patterns, the comparator 150 may output a plurality of inversion control signals SEL corresponding to each information. Can be composed of dogs. That is, the inversion control signal SEL includes a plurality of control signals corresponding to the information on the plurality of patterns. In this case, the inversion control signal SEL may be applied to the inversion signal generator 160 in parallel through a plurality of lines. Alternatively, the inversion signal generator SEL may be serially transmitted through one line. 160 may be applied.

The inversion signal generator 160 receives the inversion control signal SEL from the comparator 150 and outputs an inversion selection signal REV in response to the inversion control signal SEL. The inversion selection signal REV is applied to the data driver 200 to determine an inversion method of the display panel 500.

The inversion scheme includes, for example, frame inversion inverted in units of frames, line inversion inverted in units of lines, and dot inversion inverted in units of dots. In addition, the dot inversion includes, for example, 1-by-1 dot inversion in which inversion occurs by one dot and 2-by-1 dot inversion in which inversion occurs by two dots.

That is, the inversion signal generator 160 outputs an inversion selection signal 160 that determines one of inversion methods of the frame inversion, line inversion, and dot inversion in response to the inversion control signal SEL. The inversion signal generator 160 also determines an inversion method of one of the 1-by-1 dot inversion and the 2-by-1 dot inversion even when the dot inversion is selected. ) Can be printed.

As such, when the consumption current required to display the predetermined patterns on the display panel 500 varies greatly according to the inversion scheme, the inversion signal generator 160 selects an inversion scheme with less consumption current. The inverted selection signal REV is generated.

The control signal generator 170 receives and controls a vertical synchronous signal Vsync, a horizontal synchronous signal Hsync, a main clock MCK, and a data enable signal DE to control the data start signal STH. The data load signal Load, the data synchronization signal DOT, the scan start signal STV, the scan clock GCK, and the voltage drive signal Pcon are output. In this case, the data start signal STH, the data load signal Load and the data synchronization signal DOT are applied to the data driver 200, and the scan start signal STV and the scan clock GCK are scanned. The driving unit 300 is applied, and the voltage driving signal Pcon is applied to the driving voltage generation unit 400.

The timing controller 100 may further include an oscillator (not shown) for generating an internal clock for synchronizing the pattern storage memory 140, the comparator 150, the inverted signal generator 160, and the like. The internal clock preferably vibrates with the same frequency and phase as the main clock MCK.

Hereinafter, the effect of the image displayed on the display device and the inversion method of driving the display device will be described with reference to the drawings.

3 is a plan view conceptually illustrating a first image displayed on the display device of FIG. 1. 4A and 4B are waveform diagrams of data driving signals applied to display the first image of FIG. 3. Specifically, FIG. 4A is a waveform diagram of a data driving signal according to 2-by-1 dot inversion, and FIG. 4B is a waveform diagram of a data driving signal according to 1-by-1 dot inversion.

Referring to FIG. 3, the first image displayed on the display panel 500 is an image displayed by using one example of a 1 dot sub checker pattern. An example of the one-dot sub checker pattern includes red black (RB) and red white (RW) sequentially arranged in accordance with the data line, green black (GB) and green white (GW) sequentially arranged, and blue black. (RB) and blue white (RW) are sequentially arranged. On the other hand, in the one-dot sub checker pattern, red black (RB), green black (GB), and blue black (RB) are sequentially arranged according to the scan line, and red white (RW), green white (GW), and blue are sequentially arranged. White (RW) is arranged sequentially.

Referring to FIG. 4A, the data driving signal is a signal for displaying the first image and is inverted by 2-by-1 dot inversion. The data driving signal has a voltage close to the reference voltage AVDD or the ground voltage GND to implement the red black RB, the green black GB, and the blue black RB. On the other hand, the data driving signal has a voltage slightly higher or slightly lower than the common voltage Vcom to implement the red white, RW, GW, and WWW. The reference voltage AVDD is, for example, 5 V, and the common voltage Vcom is 2.5 V, which is half of the reference voltage AVDD.

When the data driving signal has a voltage greater than the common voltage Vcom, it is referred to as positive polarity, and when the data driving signal has a voltage lower than the common voltage Vcom, it is called negative polarity. Therefore, the data driving signal shown in FIG. 4A is composed of positive black, positive white, negative black, and negative white in the present frame, and negative black and negative white in the next frame. , Positive black, positive white and the like.

Referring to FIG. 4B, the data driving signal is another signal for displaying the first image, and is inverted by 1-by-1 dot inversion. The data driving signal shown in FIG. 4B consists of positive black, negative white, positive black, negative white, etc. in the current frame, and negative white, positive black, negative white, positive in the next frame. Polar black and the like. Here, the current consumption of the data drive signal shown in FIG. 4A is about 100 mA less than that of the monitor of 15.4 inches compared to the current consumption of the data drive signal shown in FIG. 4B.

Therefore, when the display panel 500 displays the 1 dot sub checker pattern, the driving by 2-by-1 dot inversion has a lower current consumption.

5 is a plan view conceptually illustrating a second image displayed on the display device of FIG. 1. 6A and 6B are waveform diagrams of data driving signals applied to display the second image of FIG. 5. Specifically, FIG. 6A is a waveform diagram of a data driving signal according to 2-by-1 dot inversion, and FIG. 6B is a waveform diagram of a data driving signal according to 1-by-1 dot inversion.

Referring to FIG. 5, the second image displayed on the display panel 500 is an image displayed by, for example, one of two dot patterns. An example of the two dot pattern includes red black (RB), red black (RB), red white (RW) and red white (RW) sequentially arranged in accordance with the data line, and green black (GB) and green black ( GB), green white (GW) and green white (GW) are sequentially arranged, and blue black (RB), blue black (RB), blue white (RW) and blue white (RW) are sequentially arranged. On the other hand, the two dot patterns are sequentially red black (RB), green white (GW), blue black (BB), red white (RW), green black (GB) and blue white (BW) according to the scan line. Are arranged.

Referring to FIG. 6A, the data driving signal is a signal for displaying the second image, and is inverted by 2-by-1 dot inversion. The data drive signal shown in FIG. 6A is composed of negative black, positive black, positive white, and negative white in the current frame, and positive black, negative black, negative white, and positive in the next frame. Polar white and the like.

Referring to FIG. 6B, the data driving signal is another signal for displaying the second image, and is inverted by 1-by-1 dot inversion. In the current frame, the data driving signal shown in FIG. 6B is composed of positive black, negative black, positive white, negative white, and the like, and in the next frame, negative black, positive black, negative polar white, positive Polar white and the like. Here, the current consumption of the data drive signal shown in FIG. 6B is about 20 mA less than that of the monitor of 15.4 inches compared to the current consumption of the data drive signal shown in FIG. 6A.

Therefore, when the display panel 500 displays the two dot pattern, driving by 1-by-1 dot inversion has a lower current consumption.

According to the present exemplary embodiment, the external data signal DATA1 applied from the outside is compared with data information including the predetermined patterns in units of frames, and then the inversion method of the display panel 500 is changed according to the predetermined pattern. By displaying an image, the current consumption can be further reduced.

<Method for driving display device>

7 is a flowchart illustrating a method of driving a display device according to an exemplary embodiment of the present invention.

1 and 7, as a method of driving a display device, first, a data signal generated by an external graphic controller is applied to the timing controller 100 of the display device (S10).

The data signal applied to the timing controller 100 is compared with reference data of a predetermined pattern on a frame-by-frame basis to determine whether it is the same (S20).

If the data signal is not the same as compared with the reference data, the display panel 500 of the display device is driven in a first inversion method to display an image (S30).

On the other hand, when the data signal is the same as compared with the reference data, the display panel 500 of the display device is driven in a second inversion method different from the first inversion method to display an image (S40).

According to the present exemplary embodiment, by checking whether the data signal applied from the outside is the same as the reference data and driving the display panel 500 by selecting one of the first and second inversion methods, the current consumption is increased. Less inversion method can be selected.

According to such a display device and a driving method thereof, an external data signal applied from the outside is compared with data information including predetermined patterns in units of frames, and then an image is displayed by changing an inversion method of the display panel according to the predetermined patterns. Therefore, the current consumption can be further reduced.

In the detailed description of the present invention described above with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (6)

Display panel; The second data signal, the data control signal, and the scan control signal are output in response to the first data signal and the external control signal applied from the outside, and the third data signal corresponding to the predetermined pattern for each frame is output to the first data signal. A timing controller configured to output an inversion selection signal in comparison with the control unit; A data driver configured to control the display panel by receiving the second data signal, a data control signal, and an inversion selection signal, and output a data driving signal whose inversion scheme is changed based on the inversion selection signal to the display panel; And And a scan driver for receiving the scan control signal and outputting a scan driving signal to the display panel. The method of claim 1, wherein the timing controller A data signal generator for rearranging the first data signal and outputting the second data signal; An inversion selector configured to output the inversion selection signal by comparing the first data signal with the third data signal in each frame; And And a control signal generator for outputting the data control signal and the scan control signal in response to the external control signal. The method of claim 1, wherein the inversion method includes a frame inversion, a line inversion, and a dot inversion, and the inversion selection signal is a signal for selecting any one of the inversion method of the frame inversion, line inversion, and dot inversion. Display device. The method of claim 1, wherein the timing controller, A first memory configured to output a first data signal of a previous frame previously stored while storing a first data signal of a current frame applied from the outside; A second memory for storing data information corresponding to a predetermined pattern and outputting the third data signal; And And an inversion selection unit for comparing the first and third data signals and outputting the inversion selection signal if the first and third data signals are the same. The method of claim 4, wherein the inversion selector A comparator that receives the first and third data signals from the first and second memories, compares the first and third data signals, and outputs an inversion control signal when the first and third data signals are the same; And And an inversion signal generator for receiving the inversion control signal from the comparator and outputting an inversion selection signal for determining an inversion method of a display panel in response to the inversion control signal. Applying an external data signal to the display device; Outputting an inversion selection signal by comparing the data signal with data information of a predetermined pattern for each frame; And And driving the display device in an inversion method determined according to the inversion selection signal.

Images