KR101235105B1 - Field Sequential Color LCD and the driving method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to an FSC liquid crystal display panel, a liquid crystal display device, and a driving method thereof having improved cross talk.

To this end, the present invention provides n data lines extending in a first direction; M scan lines extending in a second direction crossing the first direction; A first pattern liquid crystal pixel column having a thin film transistor connected to an odd data line of the n data lines; A field sequential color liquid crystal display panel including a second pattern liquid crystal pixel column having a thin film transistor connected to an even data line among the n data lines and a liquid crystal display device having the same are provided. Dot-in of an FSC liquid crystal display device is provided. By enabling the version drive, there is an advantage that the crosstalk phenomenon does not occur. In particular, when applied to small models for mobile, it has the advantage of low power consumption and high quality image quality.

Description

Field sequential color liquid crystal display panel and liquid crystal display device and driving method thereof

1 is a view for explaining a method of driving a field sequential color mode;

2 is a view for explaining the crosstalk generated according to the color pattern change in the conventional frame inversion driving type FSC liquid crystal display device;

3 is a block diagram showing a part of the structure of a source driver IC for a conventional frame inversion driving type FSC liquid crystal display device;

4 is a signal waveform diagram for explaining a cause of occurrence of the crosstalk line of FIG. 2 by the source driver IC of FIG.

5 is a plan view schematically illustrating only a partial region of a pixel structure of an FSC liquid crystal display panel according to the present invention.

6 is a flowchart illustrating a method of driving an FSC liquid crystal display device according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

DL1 ~ DLn: Data Line SL1 ~ SLm: Scan Line

PXL: Liquid Crystal Pixel TFT: Thin Film Transistor

PTN1, PTN2: first and second pattern liquid crystal pixel columns

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a field sequential color liquid crystal display panel having an improved cross talk phenomenon, a liquid crystal display device, and a driving method thereof.

BACKGROUND ART [0002] Liquid crystal displays (LCDs), which tend to increase the practical use gradually, control a rotation angle of a liquid crystal in a plurality of liquid crystal cells arranged in a matrix form and a liquid crystal cell, respectively, (Backlight unit) is transmitted to a liquid crystal panel provided with a TFT (thin film transistor) for supplying image data for displaying a desired image on the screen.

As a light source used in such a backlight unit, a cold cathode fluorescent lamp (hereinafter referred to as 'CCFL') is mainly used. Such a backlight unit has a trend of miniaturization, thinning, and weight reduction. In accordance with this trend, light emitting diodes (LEDs), which are advantageous in terms of power consumption, weight, and brightness, have been proposed instead of CCFLs used in backlight units.

Through the backlight unit using the LED, the field sequential color (FSC) driving method is proposed to obtain better image quality.

Field sequential color (FSC) driving method drives LEDs of three primary colors (red, green, blue) sequentially without displaying color filters. This is a driving method which can display the mixed color by using the afterimage effect by a human eye.

More specifically, the display time of one frame on the panel is divided into three periods of red, green, and blue, and each backlight is sequentially illuminated with intervals in time.

As shown in FIG. 1, this FSC driving method is divided into three subframes (1 Sub-frame) of red (R), green (G) and blue (B) frame = 5.56 ms).

Each subframe is divided into a data writing time (DW = 1.69 ms) through TFT scanning, a liquid crystal response time (LR = 1.5 ms) according to data writing, and a backlight emitting time (BL = 2.37 ms) The time BL during which the backlight can be turned on is the time excluding the data writing time DW and the liquid crystal response time LR.

In the case of the FSC driving, the data input for RGB to the liquid crystal panel is sequentially generated once in the same ratio (R: G: B = 1: 1: 1) within one vertical synchronization period, and the corresponding backlight The light source is also synchronized in the same manner so that the red (R) light source, the green (G) light source, and the blue (B) light source are sequentially turned on. At this time, each light source is an LED or a fluorescent lamp, and each of the red, green, and blue light sources are sequentially arranged.

Among the FSC liquid crystal display devices driven in the above manner, the FSC liquid crystal display device applied to a small model mobile device displays a specific color pattern through a frame inversion driving method, for example, after displaying a white pattern in one frame. When the gray pattern is displayed on the screen, a clear crosstalk line is formed.

In more detail, as shown in FIG. 2, the mobile compact model FSC is formed in the data line in the horizontal direction in the liquid crystal panel 1 so that data is input from the left side (or may be the right side) of the liquid crystal panel 1. When displaying a screen having an area divided into a white pattern 10 and a gray pattern 20 in one frame screen of the liquid crystal display device, a crosstalk line ( CTL) is generated.

This cross talk line is caused by an operation defect in a digital-to-analog converter (hereinafter, referred to as 'DAC') of a source driving IC (not shown) that outputs data to the liquid crystal panel 1. The cause of generation of the crosstalk line will be described.

FIG. 3 is a block diagram showing a part of a configuration inside a source driver IC for an FSC liquid crystal display device of a frame inversion driving method, and particularly illustrates a plurality of channel DACs configured to output selected data to respective data lines.

Referring to the configuration of FIG. 3, the first channel DAC (DAC1) and the first channel for outputting data to the data lines of the liquid crystal panel (1 in FIG. An n-channel DAC (DACn) is shown, and each of the channel DACs (DAC1, DACn) receives data from the buffer 50. At this time, the buffer 50 has as many output lines as the number of gray levels that the output data can have, so that the data of different gray levels are output to different output lines. That is, M data lines are provided when the data is data for representing M gray scales.

Therefore, the gray data and the white data are output from the buffer 50 in different lines, and the data output from the buffer 50 is input to the respective channel DACs DAC1 and DACn.

Each of the channel DACs DAC1 and DACn has internal output lines corresponding to the number of output lines of the buffer 50, and each internal output line is configured with a switch to control the output of data.

In brief, when gray data is output from the buffer 50, gray data is input to each channel DAC (DAC1, DACn) through the node B, and at the same time, the gray data is input to each channel DAC (DAC1). , The internal output line of DACn) turns on the switches (SW G1, SW Gn) for gray data output and the switches of the other internal output lines are off (off) to 1st data line and nth data line, respectively. Output gray data.

Next, when white data is output from the buffer 50, white data is input to each channel DAC (DAC1, DACn) through the node C, and at the same time, the white data of each channel DAC (DAC1, DACn) to which the white data is input is input. The internal output line turns on the switches (SW W1, SW Wn) for outputting white data, and the switches of other internal output lines are turned off to output white data to the 1st data line and the nth data line, respectively. do.

Of course, simultaneously outputting a plurality of gray level data from the buffer 50 and separately controlling the switch of the internal output line of each channel DAC (DAC1, DACn) to output data of different gray levels to the plurality of data lines at the same time. It may be.

However, when the image in which the white pattern region is inserted into the gray pattern region as shown in FIG. 2 is displayed through the source driver IC having the channel DACs DAC1 and DACn as shown in FIG. Gray data is input to the data line after white data is output.

To this end, in the n-th channel DAC (DACn), after the output of the white data, the switch SW Wn of the internal output line for white data output is turned off and at the same time, the switch SW Gn of the internal output line for gray data output. At this moment, as shown in the graph of FIG. 4, the internal output line for outputting the white data and the internal output line for outputting the gray data are simultaneously turned on at the same time so that an electrical short is generated. ), And the white data charged in node A is flowed back toward the switch SW Gn of the gray data output internal output line (indicated by 'T' in FIG. 4), and eventually through the node B. It is delivered to the internal output line for gray data output of the channel DAC, and eventually, white data is output to the liquid crystal panel through all the channel DACs.

Accordingly, as shown in FIG. 2, a bright crosstalk line CTL is generated in the entire line of the portion where the data input of the white pattern region ends in the liquid crystal panel (1 of FIG. 2).

In order to improve crosstalk in the mobile small model FSC liquid crystal display device, in which the frame inversion driving method is mainly used, driving in a dot-inversion method in which data of different polarities are applied between adjacent liquid crystal pixels, as is widely known, is required. Although it is preferable, there is no suggestion for realizing the dot-inversion driving scheme.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the dot-inversion driving FSC liquid crystal display device and its driving method which can improve the cross talk phenomenon occurring in the frame inversion driving type FSC liquid crystal display device. The purpose is to provide.

The present invention to achieve the above object, n data lines extending in the first direction; M scan lines extending in a second direction crossing the first direction; A first pattern liquid crystal pixel column having a thin film transistor connected to an odd data line of the n data lines; A field sequential color liquid crystal display panel including a second patterned liquid crystal pixel column connected to a thin film transistor is connected to an even-numbered data line among the n data lines.

Each of the first and second pattern liquid crystal pixel columns may include a plurality of liquid crystal pixels arranged in the second direction.

The first patterned liquid crystal pixel column and the second patterned liquid crystal pixel column are each composed of two adjacent horizontal pixel columns.

The first pattern liquid crystal pixel column and the second pattern liquid crystal pixel column may be configured to alternate with each other.

Each of the liquid crystal pixels is configured in an area between the odd data line and the scan line.

In addition, the present invention provides a thin film transistor in n data lines extending in a first direction, m scan lines extending in a second direction crossing the first direction, and an odd-numbered data line among the n data lines. A liquid crystal panel having a first patterned liquid crystal pixel column coupled thereto and a second patterned liquid crystal pixel column having a thin film transistor connected to an even-numbered data line of the n data lines; A scan driver for outputting a scan signal to each scan line; A source driver for outputting image data to each of the data lines; Provided is a field sequential color liquid crystal display device including a backlight unit for supplying light to the liquid crystal panel.

The first pattern liquid crystal pixel column and the second pattern liquid crystal pixel column may be pixel columns in which a plurality of liquid crystal pixels are arranged in the second direction.

The first patterned liquid crystal pixel column and the second patterned liquid crystal pixel column are each composed of two adjacent horizontal pixel columns.

The first pattern liquid crystal pixel column and the second pattern liquid crystal pixel column may be configured to alternate with each other.

Each of the liquid crystal pixels is configured in an area between the odd data line and the scan line.

The backlight unit is characterized in that each of the light source for emitting red, green, blue color light is provided.

In addition, the present invention comprises the steps of simultaneously applying a scan signal to the s-th and s + 2th scan line; Image data is applied to a plurality of data lines in synchronization with the scan signal, and image data input to an odd data line is input to a liquid crystal pixel connected to the s-th scan line, and image data input to an even data line is Inputting to a liquid crystal pixel connected to the s + 2th scan line; simultaneously applying scan signals to the s + 1 < th > and s + 3 < th > scan lines; Image data is applied to a plurality of data lines in synchronization with the scan signal, and image data input to an odd data line is input to a liquid crystal pixel connected to the s + 1th scan line and input to an even data line. A method of driving a field sequential color liquid crystal display device may include inputting data into a liquid crystal pixel connected to the s + 3 th scan line.

In the driving method, each step is repeated to display one screen, wherein s is a natural number increased by 4 starting from 1 and sequentially entered.

In the driving method, when the image data is applied to the plurality of data lines, one or more lights of red, green, and blue colors are supplied to each of the liquid crystal pixels.

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

FIG. 5 is a plan view schematically illustrating a pixel structure of a field sequential color (hereinafter, referred to as "FSC") liquid crystal display panel according to an exemplary embodiment of the present invention.

 The FSC liquid crystal display panel according to the present invention is a dot-inversion type mobile device that can improve the crosstalk line generation problem occurring in the color pattern change region of the liquid crystal panel by a switching short phenomenon in the channel DAC of the source driver IC. A small size liquid crystal display device is proposed, and FIG. 5 illustrates a pixel structure of a liquid crystal display panel for driving such dot-in version.

Looking at the structure in detail, n data lines DL1, DL2, ..., DLn extending in the vertical direction in the first direction and m scan lines SL1, SL2, .. extending in the horizontal direction in the second direction. , SLm) are formed to cross each other, and a thin film transistor (TFT) is configured in a portion where each data line and the scan line cross each other.

Also, the liquid crystal pixel PXL is configured in an area formed by the scan lines SL1, SL2,..., SLm and the odd-numbered data lines DL1, DL3, DL5,... In this case, the data line formed to penetrate the liquid crystal pixel PXL is actually a line formed under the liquid crystal pixel PXL.

In addition, each liquid crystal pixel PXL is divided into liquid crystal pixel columns having two patterns according to data lines connected to the thin film transistor TFT. As illustrated in FIG. 5, liquid crystal pixels arranged in a scan line direction A first pattern liquid crystal pixel column PTN1 having a thin film transistor TFT connected to an odd-numbered data line DL1, DL3, DL5,..., Of the n data lines, and the n data lines. The second pattern liquid crystal pixel column PTN2 is connected to the thin film transistor TFT to the even-numbered data lines DL2, DL4, DL6,...

The liquid crystal pixel columns PTN1 and PTN2 of the patterns are formed in a direction parallel to the scan lines SL1, SL2,..., SLm, and two identical pattern horizontal pixel rows adjacent to each other are formed. It is configured alternately. That is, as shown in FIG. 5, if the first pattern liquid crystal pixel column PTN1 is configured as two and the second pattern liquid crystal pixel column PTN2 is configured as two, the next two horizontal pixel columns not shown are Naturally, the first pattern horizontal pixel column PTN1 is configured.

The liquid crystal display panel operation of the pixel structure as described above will be described with reference to the flowcharts of FIGS. 5 and 6.

First, the FSC liquid crystal display according to the present invention comprises: a first step (ST1) of simultaneously applying a scan signal to the s-th and s + 2th scan lines; Image data is applied to a plurality of data lines in synchronization with the scan signal, and image data input to an odd data line is input to a liquid crystal pixel connected to the s-th scan line, and image data input to an even data line is A second step (ST2) of inputting to a liquid crystal pixel connected to the s + 2th scan line; a third step ST3 of simultaneously applying scan signals to the s + 1th and s + 3th scanlines; Image data is applied to a plurality of data lines in synchronization with the scan signal, and image data input to an odd data line is input to a liquid crystal pixel connected to the s + 1th scan line and input to an even data line. Data is input to the liquid crystal pixel connected to the s + 3 th scan line in a fourth step (ST4), and after the fourth step (ST4), each step is repeated to display a screen, wherein s is 1 It is a method of sequentially replacing natural numbers starting from 4 and incremented by 4 (ST5).

Accordingly, when the respective steps are applied to the liquid crystal display panel of FIG. 5, the signal starts at s = 1, and thus the scan signals are simultaneously applied to the first and third scan lines SL1 and SL3 through the scan driver (not shown). (Corresponds to ST1)

Subsequently, image data is applied to each of the data lines DL1, DL2, ..., DLn through a source driver (not shown) in synchronization with the scan signal. Therefore, image data is applied to the first horizontal pixel column through the odd-numbered data lines DL1, DL3, ..., and image data is applied to the third horizontal pixel column through the even-numbered data lines DL2, DL4, .... (Corresponds to ST2)

Next, scan signals are simultaneously applied to the second and fourth scan lines SL2 and SL4 (corresponding to ST3).

Thereafter, image data is applied to each of the data lines DL1, DL2, ..., DLn in synchronization with the scan signal. Accordingly, image data is applied to the second horizontal pixel column through the odd-numbered data lines DL1, DL3, ..., and image data is applied to the fourth horizontal pixel column through the even-numbered data lines DL2, DL4, .... (Corresponds to ST4)

Next, adding 4 to the s value results in s = 5 (corresponding to ST5), and repeating the operations of (ST4) to (ST4) in the fifth to eighth horizontal pixels (not shown). The image data will be applied, and this driving (ie, ST1 to ST5) is repeated until the image data is input to the horizontal pixel columns of the entire liquid crystal display panel. Of course, since the FSC is driven, at least one of the red, green, and blue colors may be supplied through a backlight unit (not shown) having red, green, and blue light sources, respectively, after image data is applied.

The FSC liquid crystal display panel, the liquid crystal display device, and the driving method thereof according to the present invention described above have the advantage that the dot-inversion driving of the FSC liquid crystal display device is possible, so that no crosstalk phenomenon occurs. In particular, when applied to small models for mobile, it has the advantage of low power consumption and high quality image quality.

Claims (14)

N data lines extending in a first direction; M scan lines extending in a second direction crossing the first direction; A first pattern liquid crystal pixel column having a thin film transistor connected to an odd data line of the n data lines; A second pattern liquid crystal pixel column in which a thin film transistor is connected to an even-numbered data line of the n data lines And the first patterned liquid crystal pixel column and the second patterned liquid crystal pixel column are each composed of two adjacent horizontal pixel columns. The method according to claim 1, The first pattern liquid crystal pixel column and the second pattern liquid crystal pixel column each have a plurality of liquid crystal pixels arranged in the second direction. delete The method according to claim 1, The first pattern liquid crystal pixel column and the second pattern liquid crystal pixel column are alternately configured. The method according to claim 1, Each of the liquid crystal pixels includes a field sequential color liquid crystal display panel, which is configured in an area between the odd data line and the scan line. A first pattern in which n data lines extending in a first direction, m scan lines extending in a second direction crossing the first direction, and a thin film transistor are connected to an odd data line among the n data lines. A liquid crystal panel having a liquid crystal pixel row and a second pattern liquid crystal pixel row having a thin film transistor connected to an even-numbered data line of the n data lines; A scan driver for outputting a scan signal to each scan line; A source driver for outputting image data to each of the data lines; Back light unit for supplying light to the liquid crystal panel And the first patterned liquid crystal pixel column and the second patterned liquid crystal pixel column are each composed of two adjacent horizontal pixel columns. The method of claim 6, The first pattern liquid crystal pixel column and the second pattern liquid crystal pixel column are pixel sequences in which a plurality of liquid crystal pixels are arranged in the second direction, respectively. delete The method of claim 6, And the first pattern liquid crystal pixel column and the second pattern liquid crystal pixel column are alternately configured. The method of claim 6, The field sequential color liquid crystal display device, wherein each liquid crystal pixel is configured in an area between an odd data line and a scan line. Claim 11 was abandoned when the registration fee was paid. The method of claim 6, The backlight unit is a field sequential color liquid crystal display device, characterized in that each of the light source for emitting red, green, blue light is provided simultaneously applying scan signals to the s-th and s + 2th scan lines; Image data is applied to a plurality of data lines in synchronization with the scan signal, and image data input to an odd data line is input to a liquid crystal pixel connected to the s-th scan line, and image data input to an even data line is Inputting to a liquid crystal pixel connected to the s + 2th scan line; simultaneously applying scan signals to the s + 1 < th > and s + 3 < th > scan lines; Image data is applied to a plurality of data lines in synchronization with the scan signal, and image data input to an odd data line is input to a liquid crystal pixel connected to the s + 1th scan line and input to an even data line. Inputting data into a liquid crystal pixel connected to the s + 3 th scan line Field sequential color liquid crystal display device driving method comprising a The method according to claim 12, Displaying one screen by repeating the above steps, wherein s is a field sequential color liquid crystal display driving method characterized in that the natural number increased by 4 starting from 1 sequentially Claim 14 has been abandoned due to the setting registration fee. The method according to claim 12, And when the image data is applied to the plurality of data lines, at least one of red, green, and blue light is supplied to each of the liquid crystal pixels.

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