KR101282288B1 - Two color sequential plus driving method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to an improvement in an uncharged problem caused by a decrease in gate on time due to the insertion of a black color voltage in a two color sequential plus liquid crystal display.

To this end, in the present invention, all the gate lines of the liquid crystal panel are divided into first to third blocks (n-th block), and the gate lines of the first to third blocks (n-th block) are sequentially turned on for each block. In this state, when the data application is prepared by the gate on signal, the black color voltage is applied to each subframe, thereby improving the uncharged problem caused by the reduction of the gate on time.

Correspondingly, power consumption is reduced due to the reduction of the data frequency through the improvement of the uncharged problem.

Description

Two color sequential plus driving method

1 is a cross-sectional view showing a conventional field sequential color liquid crystal display device.

2 is a view showing lamp driving of a TCS + liquid crystal display;

3 is a view showing lamp driving of a TCS + liquid crystal display device having improved color reproducibility;

4 is a plan view showing an array substrate for a TCS + liquid crystal display;

5 is a plan view showing an array substrate for a TCS + liquid crystal display according to the present invention.

Description of the Related Art [0002]

130 substrate 140 pixel electrode

171, 172, 173: first to third driver IC 180: gate driver

190: data driver T: thin film transistor

GL1, GL2, GL3: first to third gate lines DL: data lines

B1, B2, B3: first to third blocks

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to an uncharged problem caused by a decrease in gate on time due to the insertion of a black color voltage in a two-color sequential plus liquid crystal display. It's about doing.

In general, a liquid crystal display device includes a liquid crystal panel including a plurality of liquid crystal cells arranged in a matrix, a plurality of control switching elements for switching (switching) a video signal to be supplied to each of the liquid crystal cells, and a rear surface of the liquid crystal panel. It is configured to include a backlight unit located in.

In this case, a desired image is realized by adjusting the amount of light transmitted from the backlight unit to the liquid crystal panel.

Cold Cathode Fluorescent Lamps (CCFLs) are mainly used as the lamps used in the backlight unit, and the backlight units using the CCFLs include fluorescent lamps serving as light sources, and wrap the fluorescent lamps. And a light guide plate for converting light incident from the fluorescent lamp into a surface light source, a reflecting plate positioned below the light guide plate, and an optical member configured on the light guide plate.

In the trend of miniaturization, thinning, and weight reduction, light emitting diodes (LEDs), which are advantageous in power consumption, weight, and luminance, have been proposed instead of the CCFL used in the backlight unit. In addition, the backlight unit using the LED generally uses a field sequential color (FSC) driving method to realize better image quality.

The FSC driving method does not use a color filter of red (R), green (G), and blue (B) in displaying color, and instead of driving the three primary colors of the backlight unit, the afterimage effect of the human eye is achieved. It is a driving method for displaying color using.

Hereinafter, a conventional field sequential color driving method will be described with reference to the accompanying drawings.

1 is a cross-sectional view showing a conventional field sequential color liquid crystal display device.

As shown in the drawing, the liquid crystal display device 5 according to the FSC driving method includes an array substrate 30 on which a thin film transistor T and a pixel electrode 40 are formed, and a color filter substrate 10 on which a common electrode 20 is formed. Oppositely bonded, including the liquid crystal cell 50 filled between the color filter substrate 10 and the array substrate 30 to form a liquid crystal panel 70, and supplies a light source from the back of the liquid crystal panel 70 And a backlight unit 60 including red light emitting diodes 60a and red, green light emitting diodes 60b and green, and blue light emitting diodes 60c and blue.

In this case, the thin film transistor T includes a gate electrode 25, a semiconductor layer 36, and source and drain electrodes 32 and 34, and a non-pixel section below the color filter substrate 10. It further comprises a black matrix 15 and an overcoat layer 17 configured to shield incident light.

This FSC driving method does not use a color filter to express the color of an image, and sequentially turns on the red (R), green (G), and blue (B) light sources of the backlight unit 60 so that the human Since the color is displayed through the afterimage effect by the eyes, it has advantages of high transmittance, high resolution, and the number of driving ICs compared to the method using a color filter.

In the above-described FSC driving method, each frame is divided into three subframes of the first to third subframes so that the light sources of red (R), green (G), and blue (B) are sequentially turned on in each subframe.

However, the FSC driving method is proposed as a two-color sequential plus driving method (hereinafter, abbreviated as TCS + driving method) in which the FSC driving method is partially modified due to a limitation that cannot cope with the trend of large area of the liquid crystal panel. In addition, the two-color sequential plus driving method further includes a cyan light source in addition to red, green, and blue light sources, and arbitrarily bundles each light source to drive two sub-frames, thereby coping with large areas according to driving margins. have.

Hereinafter, a TCS + driving method will be described with reference to the accompanying drawings.

2 is a diagram illustrating lamp driving of a TCS + liquid crystal display.

As shown, the TCS + driving method arbitrarily bundles red, green, blue, and cyan light sources for the entire frame on the liquid crystal panel (1-frame), thereby providing two sub-frames. The light is repeatedly lit in a frame, and the image is expressed using a color filter of two-color green (G) and magenta (Magenta) formed on the color filter substrate.

In the sub-frame, the four light sources emit light to supply a data voltage to the liquid crystal cell using a scan pulse during the data writing time (AP), and the data supplied to the liquid crystal cell during the liquid crystal response time (WP) is constant. The lamp is turned on by the lamp driver during the lamp lighting time FP to supply light to the liquid crystal cell.

In this case, the time that the actual light source emits light in each subframe is the remaining time minus the data writing time AP and the liquid crystal response time WP.

In detail, in the conventional TCS + driving method, data signals for RGBC of the liquid crystal panel are sequentially generated once at the same ratio (R: G: B: C = 1: 1: 1: 1) within one vertical period. The corresponding light source of the backlight unit is also synchronized in the same manner so that the red (R), green (G), blue (B), and cyan (C) light sources are sequentially turned on, and the remaining two-color green (G) and magenta ( The image is realized through the color filter and color combination of M).

Here, in order to visually implement a white screen using the light emitting diode, the luminance of each RGBC light source requires more red (R) / green (G) / cyan (C) light sources than the blue (B) light sources. Bar, when the lighting time of each of the red (R), green (G), blue (B), and cyan (C) light sources is implemented in a ratio of 1: 1: 1: 1, This can be compensated by increasing the output intensity of the (R) / green (G) / cyan (C) light source.

However, the above-described TCS + driving method causes a problem in that color reproduction is reduced due to a mixed color characteristic according to a step response of a subframe when used in a high speed liquid crystal mode.

In order to solve this problem, a method of improving color reproducibility by applying a black color voltage to each subframe has been proposed, which will be described with reference to the accompanying drawings.

3 is a diagram illustrating lamp driving of a TCS + liquid crystal display having improved color reproducibility.

As shown in the drawing, the TCS + driving method uses LED as a light source, and the driving of sub-frames divided by each color light source is used for delay driving (DP), data writing (AP), liquid crystal response (WP), and backlight driving ( FP) and the like are sequentially driven.

In this case, when one sub-frame starts, the delay driving DP improves the color mixing characteristic since all sub-frames have the same step response time by applying a voltage to all liquid crystals in advance. There is an advantage to this.

In detail, the gate-on signal is simultaneously applied to all the gate lines of the liquid crystal panel at the time when the driving of one sub-frame is started, and the black color voltage is supplied to each data line when data application is prepared by the gate-on signal. .

Here, the liquid crystal molecules are activated during the "A" period during which the black color voltage is applied, and then have a delay time for the "D" time. The mixed color characteristic due to the afterimage in the previous frame driving is inserted into each subframe. Since it is compensated by the color voltage, the color reproducibility is improved.

In this case, when the black color voltage is inserted, there is an advantage in that the mixed color characteristic can be improved. However, when the gate-on signal is sequentially applied to all the gate lines of the liquid crystal panel, the gate for inserting the black color voltage in each subframe is added. There is a disadvantage in that an uncharged problem occurs due to a decrease in the gate on time.

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

4 is a plan view illustrating an array substrate for a TCS + liquid crystal display.

As illustrated, a plurality of gate lines GL and data lines DL vertically intersect on the substrate 30 to form a matrix, and one-to-one at intersections of the gate lines GL and data lines DL. Correspondingly, the thin film transistor T and the pixel electrode 40 are configured, the gate driver 80 applying a scan signal to the gate line GL on one side of the substrate 30 and the data line DL. ) Is a data driver 90 for applying a data signal.

At this time, although not shown in detail in the drawing, the gate driver 80 is applied to all the gate lines GL of the liquid crystal panel in response to a gate control signal from a timing controller (not shown), in particular, a gate output signal. By sequentially supplying scan signals, the thin film transistors T connected to the respective gate lines GL are driven.

In this case, when controlling the gate output signal, a gate on signal for an RGBC signal and a gate on signal for inserting a black color voltage are required. The on time is cut in half, leading to uncharged problems, resulting in higher data drive frequencies and higher power consumption.

The present invention has been made to solve the above-described problem, and an object thereof is to improve the uncharged problem caused by the reduction of the gate on time due to the insertion of the black color voltage.

The two-color sequential driving method according to the present invention for achieving the above object is provided with a plurality of gate lines divided into blocks and a plurality of data lines perpendicularly intersecting the same, and the red, green, blue, cyan light source arbitrarily In driving a liquid crystal panel including a backlight unit divided into two sub-frames and a color filter composed of green and magenta,

In a state in which the plurality of gate lines are sequentially turned on in block units, when a data application is prepared by a gate on signal, a black color voltage is inserted into each subframe, which is a driving period of each block.

In this case, a driving IC may be provided according to the number of blocks, and a scan signal may be received from the driving IC through block-by-block shift operations.

All the subframes have the same step response time, and the number of blocks varies according to the resolution.

Hereinafter, a TCS + driving method according to the present invention will be described with reference to the accompanying drawings.

In the present invention, all the gate lines of the liquid crystal panel are divided into first to third blocks, and when the gate lines of the first to third blocks are turned on in units of blocks, when data application is prepared by the gate on signal, By inserting a black color voltage every sub-frame is characterized in that the uncharged problem is prevented.

5 is a plan view illustrating an array substrate for a TCS + liquid crystal display according to the present invention.

As illustrated, a plurality of first and third blocks B1, B2, and B3 may be configured to correspond to the first to third blocks B1, B2, and B3 in one direction, respectively. The first to third gate lines GL1, GL2, and GL3, the plurality of data lines DL perpendicular to the first to third gate lines GL1, GL2, and GL3 to form a matrix, and The thin film transistor T, the pixel electrode 140, and the substrate 130 configured to correspond one-to-one to a crossing point of the plurality of first to third gate lines GL1, GL2, and GL3 and the plurality of data lines DL. A gate driver 180 for applying a scan signal to the first to third gate lines GL1, GL2, and GL3 through the first to third driver ICs 171, 172, and 173 disposed at one side of the first and third driver ICs 171, 172, and 173. The data driver 190 is configured to apply a data signal to the data line DL.

In this case, the plurality of first gate lines GL1 are connected to the first driving IC 171, the plurality of second gate lines GL2 are connected to the second driving IC 172, and the plurality of third gate lines are connected. GL3 is connected to the third driver IC 173, respectively.

That is, block-specific shift operations are performed from the first to third driving ICs 171, 172, and 173 provided in the gate driver 180 to correspond to the first to third blocks B1, B2, and B3. The scan signals may be sequentially applied to the plurality of first to third gate lines GL1 to GL3.

As described above with reference to FIG. 3, the TCS + driving method uses an LED as a light source, and the driving of sub-frames divided by the color light sources is delayed driving (DP), data writing (AP), and liquid crystal response (WP). ) And four stages such as backlight driving (FP) to sequentially drive.

In this case, when one subframe starts, the delay driving DP may apply a voltage to all liquid crystals in advance to activate the liquid crystals, thereby improving the color mixing characteristic because all the subframes have the same step response time.

In this case, the gate driver 180 sequentially supplies scan signals to the first to third gate lines GL1, GL2, and GL3 in response to a gate control signal from a timing controller (not shown), in particular, a gate output signal. Then, the thin film transistor T connected thereto is sequentially driven.

The gate control signal includes a gate start pulse, a gate shift clock, a gate output signal, and the like.

In the present invention, a gate-on signal is simultaneously applied to a plurality of first gate lines GL1 of the first block B1 of the liquid crystal panel at the time when driving of one subframe is started, and data is applied by the gate-on signal. When is prepared, a black color voltage is inserted into each data line DL, a gate on signal is applied to a plurality of second gate lines GL2 configured in the second block B2, and then the gate on signal is applied to the gate on signal. When the data is ready for application, a black color voltage is inserted into each data line DL, and then a gate-on signal is simultaneously applied to a plurality of third gate lines GL3 configured in the third block B3. When data application is prepared by the gate-on signal, a black color voltage is inserted into each data line DL.

Accordingly, the TCS + driving method according to the present invention, unlike the conventional method of sequentially driving a plurality of gate lines, bundles the plurality of gate lines in block units and sequentially in block units so that the gate lines in the block are turned on at the same time. Since the gate-on time is drastically faster because of driving, the gate-on time holding time can be lengthened in proportion.

Therefore, as described above, by turning on the first to third gate lines in block units, the conventional uncharged problem generated when the gate lines of the entire liquid crystal panel are sequentially turned on can be solved. As a result, there is an advantage that the power consumption according to the reduction of the data frequency is also reduced.

At this time, the present invention is set to three blocks (B1, B2, B3), but this is only exemplary and it will be apparent that the number of the blocks may vary depending on the resolution.

In the present invention, when the black color voltage is inserted as a part of improving the color reproducibility, a plurality of gate lines are blocked and a gate signal is applied in units of blocks, thereby preventing an uncharged problem.

As a result, there is an advantage that can lower the power consumption according to the reduction of the data frequency.

Claims (4)

It includes a plurality of gate lines divided in block units, and a plurality of data lines vertically intersecting the block lines, and a backlight unit divided into two subframes by arbitrarily tying red, green, blue, and cyan light sources, and composed of green and magenta. In driving a liquid crystal panel including a color filter, In a state in which the plurality of gate lines are sequentially turned on in block units, when a data application is prepared by a gate-on signal, a black color voltage is inserted into each subframe which is a driving period of each block. . The method of claim 1, And a driving IC according to the number of blocks, and receiving a scan signal from the driving IC through block-by-block shift operation. The method of claim 1, And all the subframes have the same step response time. The method of claim 1, And the number of the blocks varies according to the resolution.

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