KR101255304B1 - Method for driving Liquid crystal display - Google Patents

Abstract

The present invention relates to a method of driving a liquid crystal display device, and the method of driving a liquid crystal display device according to the present invention is a method of driving a liquid crystal display device using a line-in version method, wherein m / m of m frames displaying an image signal is displayed. Two frames are driven by the one-line inversion method, and the remaining m / 2 frames are driven by the two-line inversion method.

Line-in version

Description

Driving method for liquid crystal display {Method for driving Liquid crystal display}

1A and 1B are views for explaining a line inversion method of a general liquid crystal panel driving method.

2 illustrates a liquid crystal display device according to the present invention.

3A to 3D are views for explaining the 1-line inversion method of the liquid crystal panel driving method according to the present invention.

4A to 4D are diagrams for describing a 2-line inversion method of a liquid crystal panel driving method according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a method of driving a liquid crystal display device which can be driven by a line-in version method.

A typical liquid crystal display device displays an image by adjusting light transmittance for each liquid crystal cell according to a signal. To this end, the liquid crystal display includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix and a driving circuit for driving the liquid crystal panel.

In the liquid crystal panel, liquid crystal cells are defined in regions where a plurality of gate lines and a plurality of data lines cross each other. Each of the liquid crystal cells is provided with pixel electrodes and common electrodes for applying an electric field. Each of the pixel electrodes is connected to one of the data lines via a thin film transistor, which is a switching element. The gate terminal of the thin film transistor is connected to one of the gate lines.

The driving circuit includes a gate driver for driving the gate lines, a data driver for driving the data lines, and a common voltage generator for driving the common electrode.

The gate driver sequentially supplies the scanning signal, that is, the gate signal to the gate lines, to sequentially drive the liquid crystal cells on the liquid crystal panel by one line.

The data driver supplies a pixel voltage signal, that is, a data signal, to each of the data lines whenever a gate signal is supplied to any one of the gate lines.

The common voltage generator supplies a common voltage signal to the common electrode.

Accordingly, the liquid crystal display device displays an image by adjusting the light transmittance by changing the liquid crystal arrangement state between the pixel electrode and the common electrode according to the pixel voltage signal for each liquid crystal cell.

In order to reduce the current consumption of the data driving integrated circuit in the liquid crystal display having such a configuration, an inversion driving method of alternately applying data voltages having opposite polarities to each adjacent pixel area is used.

The inversion driving method is a frame inversion system in which data voltages having opposite polarities are alternately applied to each frame, and a line (column) in which data voltages having opposite polarities are alternately applied at every line (column) It is divided into a version method (Line (Column) Inversion System), or a dot inversion system that alternately applies data voltages having polarities opposite to each other.

Meanwhile, in the liquid crystal panel driving method of the one-line inversion method among the inversion driving methods, as shown in FIGS. 1A and 1B, data voltages having opposite polarities are applied to each frame for each gate line. In other words, the 1-line inversion scheme applies a positive data voltage to each of the liquid crystal cells of the odd-numbered line and a negative voltage to each of the liquid crystal cells of the even-numbered line as shown in FIG. 1A in the odd frame. Apply a polarity data voltage. In the even-numbered frame, as shown in FIG. 1B, a negative data voltage is applied to each of the liquid crystal cells of the odd-numbered line, and a positive data voltage is applied to each of the liquid crystal cells of the even-numbered line.

In this 1-line inversion method, since voltages of opposite polarities are applied between adjacent lines or frames, the number of switching between the positive and negative polarities is increased compared to the frame inversion, thereby increasing the power consumption of the data driver.

An object of the present invention for solving the above problems is to provide a method of driving a liquid crystal display device using a line inversion method to reduce the power consumption.

A method of driving a liquid crystal display device according to the present invention for achieving the above object is a method of driving a liquid crystal display device using a line-in version method, wherein m / 2 frames of the m frames for displaying the video signal is 1 It is driven by the line inversion method, and the remaining m / 2 frames are driven by the two-line inversion method.

The 1-line inversion method applies a data voltage of opposite polarity to liquid crystal cells of odd-numbered lines and liquid crystal cells of even-numbered lines.

The 2-line inversion method applies a data voltage having a first polarity to the liquid crystal cells of the 4n-3th line, the liquid crystal cells of the 4n-2th line, the liquid crystal cells of the 4n-1th line, A data voltage of a second polarity opposite to the first polarity is applied to the liquid crystal cells of the 4n-th line.

And applying a common voltage of opposite polarity to the data voltages.

The first frame to the m / 2th frame of the m frames is driven by the one-line inversion method, and the 1 + m / 2th frame to the mth frame is driven by the two-line inversion method or from the m frames. The two-line inversion method is driven from the first frame to the m / 2th frame, and the one-line inversion method is driven from the 1 + m / 2th frame to the mth frame.

The 4m-3rd frame and the 4m-2nd frame of the m frames drive the 1-line inversion method, and the 4m-1th frame and the 4mth frame drive the 2 line inversion method, or 4m out of the m frames. The 3rd frame and the 4m-2nd frame drive the 2 line inversion method, and the 4m-1st frame and the 4mth frame drive the 1 line inversion method.

An embodiment of the present invention having the features as described above will be described in more detail with reference to the accompanying drawings.

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

In the liquid crystal display shown in FIG. 2, a liquid crystal panel 12 having pixel regions P having matrix shapes defined by gate lines GL1 to GLn and data lines DL1 to DLm perpendicular to each other. And a thin film transistor TFT formed at each intersection of n gate lines GL1 to GLn and m data lines DL1 to DLm, and a gate driver for driving the gate lines GL1 to GLn. 14, a line inversion data driver 16 for driving the respective data lines DL1 to DLm, a timing controller for controlling the gate driver 14 and the data driver 16; (Not shown), a plurality of pixel electrodes (not shown) formed in each of the pixel regions P, and a plurality of common electrodes formed in each of the pixel regions P and positioned between the pixel electrodes. (Not shown) and common to the common electrodes And a common voltage generating unit 18 for supplying a voltage (Vcom).

The gate driver 14 sequentially supplies a scan signal, that is, a gate signal, to the gate lines GL1 to GLn so that the thin film transistors TFT connected to the corresponding gate line are driven.

The data driver 16 is a line inversion data driver 16 that converts pixel data into a pixel voltage signal, which is an analog signal, and outputs one horizontal line of video for each horizontal period in which the gate signal is supplied to the gate line GL. The signal is supplied to the data lines DL1 to DLm.

The liquid crystal display device having such a configuration uses the line-in-version method according to the present invention to drive the liquid crystal cells on the liquid crystal panel 2.

The line inversion method according to the present invention alternately or sequentially uses the 1-line inversion method and the 2-line inversion method, but some frames of the 60 frames are 1 when 60 frames per second are transmitted. The line inversion method is used, and the rest of the frames use the two-line inversion method. However, the ratio of frames in which the 1-line inversion method and the 2-line inversion method are used out of 60 frames is 1: 1.

More specifically, the line inversion method according to the present invention implements a 1-line (or 2-line) inversion method in frames 1 to 30 of 60 frames, and 2-line (in frames 31 to 60). There is a line inversion method that implements each line inversion method by implementing the 1-line) inversion method, and 1-line (or 2-line) in 4m-3 and 4m-2 frames of 60 frames. The inversion method is implemented, and the line inversion method, which alternately implements each line inversion method, is implemented by implementing the 2-line (or 1-line) inversion method in frames 4m-1 and 4m. Here, m is a natural number.

However, although not described as an embodiment of the present invention, if the ratio of the frame in which the 1-line inversion method and the 2-line inversion method are used is 1: 1, it may be interpreted as an example of the embodiment of the present invention.

This will be described in more detail with reference to the drawings.

3A and 3B illustrate polarities of data voltages of the 1-line inversion method according to the present invention, and FIGS. 3C and 3D illustrate polarities of common voltages of the 1-line inversion method according to the present invention. One drawing.

First, in the 1-line inversion method, a positive data voltage is applied to each of the liquid crystal cells of the odd-numbered line, and a negative polarity is applied to each of the liquid crystal cells of the even-numbered line, as shown in FIG. 3A in the odd frame. Apply the data voltage. In the even-numbered frame, as illustrated in FIG. 3B, a negative data voltage is applied to each of the liquid crystal cells of the odd-numbered line, and a positive data voltage is applied to each of the liquid crystal cells of the even-numbered line.

At this time, in the 1-line inversion method, a negative common voltage is applied to common lines of odd-numbered lines, and a positive commonity is common to common lines of even-numbered lines, as shown in FIG. Apply voltage. In the even-numbered frame, as shown in FIG. 3D, a common common voltage of positive polarity is applied to a common line of odd lines, and a negative common voltage of common lines of even-numbered lines is applied.

On the other hand, Table 1 shows the number of switching from the 1-line inversion and 2-line inversion to the positive and negative data voltage, as shown in Table 1, 13200 per second in the 1-line inversion method (I.e., the number of conversions is calculated by applying a quarter common interface format (QCIF) of 220 x 176, and 220 (vertical lines) x 60 (60 frames per second) = 13200 (number of transitions to positive and negative data voltages per second)

4A and 4B illustrate polarities of data voltages of the two-line inversion method according to the present invention, and FIGS. 4C and 4D illustrate polarities of common voltages of the two-line inversion method according to the present invention. One drawing.

In addition, the 2-line inversion method applies a positive data voltage to the liquid crystal cells of the 4n-3 and 4n-2 lines in the odd frame, and the 4n-1 and 4n lines in the odd frame. A negative data voltage is applied to the liquid crystal cells of. In the even-numbered frame, as shown in FIG. 4B, a negative data voltage is applied to the liquid crystal cells of the 4n-3 and 4n-2 lines, and positive polarity is applied to the liquid crystal cells of the 4n-1 and 4n lines. Apply the data voltage.

At this time, in the 2-line inversion method, in the odd frame, a negative common voltage is applied to common lines of 4n-3 and 4n-2 lines as shown in FIG. 4C, and 4n-1 and 4n. The common voltage of the positive line is applied to the common lines of the first line. In the even-numbered frame, as shown in FIG. 4D, the common voltage of positive polarity is applied to common lines of 4n-3 and 4n-2 lines, and the common voltage of negative polarity is common to common lines of 4n-1 and 4n lines. Is applied. Where n is a natural number.

On the other hand, as shown in Table 1, in the two-line inversion method has a conversion number of 6600 times per second (that is, the conversion number is calculated by applying to the QCIF (quarter common interface format) of 220 × 176 size 110 (vertical lines / 2) x 60 (60 frames per second video signal transmission) = 6600 (number of transitions to positive and negative data voltages per second)

n-line

Conversions
One

13200
2
6600

In addition, the 1-line inversion method and the 2-line inversion method are alternately or sequentially used, as shown in Table 2, for the 1-line inversion and the 2-line inversion of the entire frame. The ratio of frames to be divided into 1: 1, 1: 2, and 1: 3 can be divided and the number of conversions corresponding to each ratio can be obtained.

1: 1
2: 1
3: 1


1-line inversion vs
2-line inversion




30 × 220 + 30 × 110

40 × 220 + 20 × 110
45 × 220 + 15 × 110
9900

11000
11550

As shown in Table 2, the conversion of the data voltage to positive and negative polarities when the ratio of the frames used in the 1-line inversion method and the 2-line inversion method out of 60 frames is 1: 1 is used. It can be seen that the number of times is 1: 2 and 1: 3 less than the number of conversions.

Therefore, in the line inversion driving method of the liquid crystal display device, the 1-line inversion method and the 2-line inversion method are alternately used, but the 1-line inversion method and the 2-line inversion method among a predetermined number of frames. When the ratio of frames used for the data is 1: 1, the number of times of switching the data voltage to the positive and negative polarities is reduced compared to the one-line inversion method alone, and the power consumption of the data driver driven by the line inversion method is reduced. Will be reduced.

According to the present invention, in the line inversion driving method of a liquid crystal display device, the 1-line inversion method and the 2-line inversion method are alternately used, but the 1-line inversion method and the 2-line of a predetermined number of frames are alternately used. By setting the ratio of the frames used for the inversion method to 1: 1, the data driver converts the data voltage to the positive and negative polarities less than the one-line inversion method alone, and drives the data in line inversion method. There is an effect that can reduce the power consumption of.

Claims (8)

In a driving method of a liquid crystal display device using a line in version method, The ratio of frames driven by the 1-line inversion method and the 2-line inversion method is 1: 1 for 60 frames displaying video signals. The 1-line inversion method is driven in a first period from the first frame to the 30th frame among the 60 frames, and the 2-line inversion method in the second period from the 31st frame to the 60th frame. Or Driving the two-line inversion method in the first period, and driving the one-line inversion method in the second period. delete delete delete delete delete delete delete

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