KR101949927B1 - Inversion driving method of liquid crystal display device - Google Patents

Abstract

The present invention discloses a method for driving a liquid crystal display device. More particularly, the present invention relates to a liquid crystal display device in which a line dim phenomenon occurring according to a line of sight characteristic of an observer is improved in a version-type liquid crystal display device which is a column driven to have different polarities from each other, And a version driving method.
According to a preferred embodiment of the present invention, there is provided a method of driving a version of a column of a liquid crystal display device including a unit pixel including a plurality of sub-pixels arranged in a matrix, the method comprising: sequentially applying a gate driving signal to a gate line; And applying a data voltage having the same polarity to each unit pixel line in the horizontal direction in synchronization with the gate driving signal so that data voltages applied to the plurality of sub pixels included in one unit pixel line are inverted with respect to each other .
Accordingly, in the present invention, the polarizations in the horizontal direction of the neighboring sub-pixels are alternately driven in the same and inverted forms to match the human polarity ratios of the neighboring unit pixels, dim) phenomenon can be eliminated and the image quality can be improved.

Description

TECHNICAL FIELD [0001] The present invention relates to an inversion driving method of a liquid crystal display device,

The present invention relates to a method of driving a liquid crystal display device, and more particularly to a method and apparatus for improving the line dim phenomenon caused by a visual characteristic of an observer in a version-type liquid crystal display device which is a column driven to have different polarities And an inversion driving method of a liquid crystal display device.

As information electronic devices for realizing high-resolution and high-quality images such as potable devices such as mobile phones and notebook computers and HDTVs are developed, a flat panel display device ) Are increasingly in demand. As such flat panel display devices, a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), and an organic light emitting diode (OLED) have been actively studied. However, And realization of a large area screen, a liquid crystal display (LCD) is in the spotlight at present.

The liquid crystal display implements an image by adjusting the light transmittance of the liquid crystal cell on the liquid crystal panel in accordance with the gray scale value of the data voltage. However, when a DC voltage is applied to the liquid crystal cell arranged in the liquid crystal panel for a long time, the light transmission characteristic of the liquid crystal cell deteriorates. That is, a DC fixing phenomenon occurs, which causes a residual image on an image displayed on the liquid crystal panel.

In order to prevent the aforementioned direct current fixing, an inversion type liquid crystal display device has been proposed in which data signals supplied to the liquid crystal cells of the liquid crystal panel are inverted based on the common voltage Vcom. In version scheme is classified into a frame inversion, a line inversion, a column inversion, and a dot inversion.

Among these, the column type version scheme has an advantage that the neighboring vertical common voltage Vcom is inverted and driven with low power because the fluctuation range of the data voltage is smaller than the version method in which the common voltage Vcom is fixed .

FIGS. 1A and 1B are diagrams showing driving modes of a conventional version-driven liquid crystal display device.

As shown in the figure, the conventional version-driven liquid crystal display device is composed of a plurality of pixels, and each pixel is defined at the intersection of the gate line in the horizontal direction and the data line in the vertical direction (not shown).

In addition, the polarities of the data voltages supplied to the liquid crystal display device are inverted for each sub-pixel line (SPL _{j + 1} , SPL _j ) (j is a natural number) in the vertical direction and for each frame. At this time, the polarities of the data voltages supplied in the horizontal direction are inverted from each other. In this column version scheme, the polarity of the data voltage is different for each neighboring pixel in the horizontal direction, but is the same for the neighboring pixels in the vertical direction.

However, one sub-pixel line in the color reproduction, the liquid crystal display device corresponds to one of the three primary colors, the unit pixel lines formed in units of pixels in the vertical direction (PL _i) (i is a natural number) has three sub-pixel line (SPL _{j +} SPL _{j + 2} ), and the ratio of the positive (+) and negative (-) sides of the sub pixel lines neighboring the unit pixel line (PL _i ) is different.

1A, the odd _-numbered unit pixel line PL _{2i-1 in} the Mth (M is a natural number) frame has a high ratio of positive (+), whereas the odd _-numbered unit pixel line PL _2i ) has a high negative polarity (-) ratio. Moreover, the M + 1 in the frame as shown in Figure 1b, odd-numbered unit pixel line (PL _2i-1) is negative (-) with the high contrast, excellent th unit pixel line (PL _2i) ratio is defined The polarity (+) is converted to a higher ratio. As a result, in the case of having such a polarity distribution on one screen, since the average ratio is the same, there is no particular problem when the observer fixes the line of sight.

However, since the image of the first unit pixel line PL1 having the positive luminance of the positive polarity (+) of the M frame is formed on the retina of the observer, a bright remnant remains, and when the observer moves his / The image of the second unit pixel line PL2 having a high positive luminance (+) is formed again in the (M + 1) th frame, so that the bright image overlaps with the bright image. This is perceived as a line dim in the eyes of the observer.

The human eye has the characteristic that the gaze is constantly changing, and even in a very short time it is difficult to fix it with the same gaze. Accordingly, the above-mentioned line dim is a main cause of deterioration of the image quality in the version-type liquid crystal display device which is a column.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a version-type liquid crystal display, which is a column driven to have a polarity opposite to that of a horizontally adjacent pixel in one frame, And it is an object of the present invention to provide a method of driving an inversion of a liquid crystal display device which solves a dim phenomenon.

In order to achieve the above object, a driving method of a liquid crystal display according to a preferred embodiment of the present invention is a method of driving a version which is a column of a liquid crystal display device including unit pixels composed of a plurality of sub-pixels arranged in a matrix Sequentially applying a gate driving signal to a gate line; And applying a data voltage having the same polarity to each unit pixel line in the horizontal direction in synchronization with the gate driving signal, wherein the data voltages applied to the plurality of sub pixels included in one unit pixel line are inverted .

The plurality of sub-pixel lines may include first to third sub-pixel lines, and a data voltage applied to the second sub-pixel line may have a polarity opposite to a data voltage applied to the neighboring first and third sub- And is inverted.

The first through third sub-pixel lines correspond to R, G, and B pixels, respectively.

And the data voltage is inverted in polarity in the next frame.

And a common voltage ripple Vcom ripple applied to the plurality of sub-pixels is fed back and removed through voltage compensation means.

The unit pixel lines are grouped into a plurality of logical blocks in one frame, and polarities of data voltages applied to the plurality of logical blocks are inverted from each other.

And the plurality of logical groups are excellent (2k, k is a natural number).

The method of driving a liquid crystal display according to a preferred embodiment of the present invention is a method of driving a liquid crystal display according to an embodiment of the present invention, in which the polarities of neighboring sub-pixels in the horizontal direction are the same and the inversions are alternately driven, There is an effect that the image quality can be improved by eliminating the line dim phenomenon caused by the characteristics.

In addition, since the polarities in the horizontal direction of the neighboring sub-pixels are the same and the inversions are alternately driven, the common voltage ripple due to the non-coincidence of the polarities of the entire screen is eliminated, thereby maximizing the reliability of the liquid- It is effective.

FIGS. 1A and 1B are diagrams illustrating driving modes of a conventional version-driven liquid crystal display device.
2 is a block diagram illustrating a structure of a liquid crystal display device applied to a driving method according to an embodiment of the present invention.
FIGS. 3A and 3B are views illustrating a method of driving an inversion mode of a liquid crystal display device according to a first embodiment of the present invention.
4 is a diagram illustrating a method of driving an in-version of a liquid crystal display device according to a second embodiment of the present invention.

Hereinafter, a liquid crystal display device and a method of driving an in-vivo version thereof according to a preferred embodiment of the present invention will be described with reference to the drawings.

2 is a block diagram illustrating a structure of a liquid crystal display device applied to a driving method according to an embodiment of the present invention.

As shown in the figure, the version-driven liquid crystal display device of the present invention includes a liquid crystal panel for displaying an image and various drive control units for controlling the liquid crystal panel.

The liquid crystal panel 100 includes a plurality of units of data lines on the substrate using the glass (DL1 ~ DL _i) and a plurality of gate lines (GL1 ~ GL _h) are cross in a matrix form, a plurality of pixel areas on the intersection point And thin film transistors T1 and T1 and a liquid crystal cell are formed in each pixel region to display a screen.

The driving control unit includes a timing control unit 110, a gate driving unit 120, a data driving unit 130, and a common voltage unit 140.

The timing controller 110 receives a timing signal such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE and a clock signal CLK input from an external system through an interface (not shown) And generates a gate control signal for driving the gate driver 120 and a data control signal for driving the data driver 130.

In addition, the timing controller 110 arranges and converts image-related data input through the interface into RGB DATA, and supplies the image data to the source driver 126.

Here, a LVDS (Low Voltage Differential Signal) interface and a TTL interface can be used as the above-mentioned interfaces. In addition, these interface functions may be collectively integrated into a single chip together with the timing controller 110.

The gate driver 120 turns on / off the thin film transistors T1 and T2 arranged on the liquid crystal panel 100 in response to gate control signals input from the timing controller 110. [ As shown in FIG.

The gate control signals include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE).

In this way, the gate driver 120 turns on the thin film transistor corresponding to the above-described control signal generating a gate drive signal is supplied to the gate lines (GL1 ~ GL _h) - by ON / OFF (turn-on / off) The data voltage supplied from the data driver 130 is applied to the pixels connected to the thin film transistors T1 and T2.

The data driver 130 selects the reference voltages of the input data in response to the data control signals input from the timing controller 110 and supplies the data voltage according to the selected reference voltage to the liquid crystal panel 100 to generate a light And the transmittance is controlled.

The data control signals include a source start pulse (SSP), a source sampling clock (SSC), a polarity control signal (POL), and a source output enable (SOE) .

The data driver 130 latches RGB data input under the control of the timing controller 110. The data driver 130 may be a shift register, a latch, a digital-to-analog converter, an output buffer, Then, the same type of polarity the RGB DATA for each analog positive polarity or a negative polarity gamma compensating voltage (GAMMA) a signal is the data voltage to the unit data lines (DL1 ~ DL _i) converted to the corresponding to the polarity control signal (POL) .

At this time, the above-mentioned data voltage is applied so that the polarities of the sub data lines SDL ₁ to SDL _j constituting each unit data line DL ₁ to DL _i are different, A data voltage applied to the G pixel line is applied to the sub data lines SDL _3j-2 and SDL _3j corresponding to neighboring R and B pixel lines around the sub data line SDL _3j-1 (j is a natural number) To be inverted.

That is, when a positive (+) data voltage is applied to the second sub data line SDL ₂ , a negative (-) data voltage is applied to the first and third sub data lines SDL ₁ and SDL ₂ do. Accordingly, the data voltages applied between the sub data lines SDL ₁ to SDL _j alternate with each other depending on the position of the line.

In accordance with the polarity of the data voltage described above, the common voltage section 140 applies the common voltage Vcom applied to the common electrode of each pixel to the first and second common voltages Vcom1 and Vcom2 having different polarities, And is applied to the sub data lines SDL ₁ to SDL _j . This structure is an example in which a plurality of common voltages having different polarities are simultaneously provided in one frame, by dividing the common electrode disposed in each pixel into at least two.

According to such a structure, in a liquid crystal display device according to the preferred embodiment of the present invention, when a version in a column is driven, a data voltage of the same polarity is applied between the unit data lines DL1 to DL _i , _the data voltages having different polarities are applied between the respective sub data lines SDL ₁ to SDL _j included in the sub-data lines SDL ₁ to SDL _i , so that the polarities applied to the respective pixels have the above-described shape, Minimizing the dim phenomenon.

Hereinafter, an inversion driving method of a liquid crystal display according to an embodiment of the present invention will be described with reference to the drawings.

FIGS. 3A and 3B are views illustrating a method of driving an inversion mode of a liquid crystal display device according to a first embodiment of the present invention.

As shown in the figure, the inversion driving method of the liquid crystal display according to the first embodiment of the present invention shows an example of the polarity for each pixel when the version in column driving in the color reproduction liquid crystal display device is driven, pixels forms a single sub-pixel line (SPL _j) (j is a natural number) in the vertical direction corresponds to the one of the one sub-pixel line (SPL _j) are the three primary colors. Also, the unit pixel line (PL _i) forming a unit pixel (i is a natural number) is made up of three sub-pixel line _{(SPL j ~ SPL j + 2} ) (j is a natural number), a unit pixel line (PL _i) the The ratio of the positive polarity (+) and the negative polarity (-) is the same in the neighboring unit pixel lines.

That is, the polarities of the data voltages are the same in the vertical direction, and are the same among the neighboring pixel lines (PL ₁ to PL _i ), but have different polarities between the three sub-pixel lines (SPL _j to SPL _{j + 2} ).

Specifically, the polarities of the data voltages supplied to the liquid crystal panel are inverted for each sub-pixel line (SPL _{j +1} , SPL _j ) (j is a natural number) and for each frame. At this time, the polarities of the data voltages supplied to the respective pixels in the horizontal direction are inverted from each other. In addition, the polarities of the data voltages applied to the unit pixel lines PL ₁ to PL _i are the same, and they are inverted for each frame.

3A, the first unit pixel line PL ₁ in the first frame includes first through third sub-pixel lines SPL _{1 and} SPL ₂ corresponding to R, G, and B pixels in the vertical direction, respectively, , SPL _3), includes a first sub-pixel line (a first sub-pixel line (SPL ₁₎ SPL ₁₎ there is applied to the data voltage of the positive polarity (+), the second sub-pixel line (SPL ₂₎ The data voltage and the inverted negative data voltage are applied.

Then, the third sub-pixel line (SPL _3), the second sub-pixel line (SPL ₁₎ of negative polarity is applied to the (-) data voltage of the positive polarity of the data voltages is reversed (+) is applied.

In addition, the first unit pixel line of the second unit pixel line adjacent to the (PL ₁₎ (PL ₂₎ is the fourth to sixth sub-pixel lines, each corresponding to the vertical direction R, G, B pixel (SPL _4, the data of the fourth sub-pixel line (SPL ₄₎ SPL ₆₎ for, and a fourth sub-pixel line (SPL ₄₎ there is applied to the data voltage of the positive polarity (+), the fifth sub-pixel line (SPL ₅ included) And the inverted negative data voltage is applied. The positive (+) data voltage in which the negative (-) data voltage applied to the fifth sub-pixel line (SPL ₅ ) is inverted is applied to the sixth sub-pixel line (SPL ₆ ).

Then, in the next second frame, all the polarities of the unit pixel line PL _i and the sub-pixel line SPL _j described above are inverted as shown in FIG. 3B.

Thus, each unit pixel line (PL _i) will have the same polarity to each other, a unit pixel line (PL _i) for forming a sub-pixel line _{(SPL j-1, SPL j} , SPL j) are inverted from each other between the neighboring line Lt; RTI ID = 0.0 > polarity

According to such a polarity structure, even if the observer's line of sight moves while viewing the image, even if the first unit pixel line PL ₁ in the Mth frame has an image with a high positive polarity, The second unit pixel line PL ₂ perceives an image having a low luminance of negative (-) in one frame, so that the images of the same luminance are not overlapped and the line dim is improved.

On the other hand, in the liquid crystal display according to the first embodiment described above, a common voltage (Vcom) ripple may occur as one frame is biased to a specific polarity.

3A, at least two sub-pixel lines SPL ₁ and SPL _{3 in the first} unit pixel line PL ₁ have the same positive polarity (+), and all the remaining unit pixel lines PL ₂ to PL _i) (i is a natural number other than 1) include a first unit pixel line (PL1) and by being to have the same polarity, the positive (+) on one frame is negative (- occupy a larger percentage than) do.

This means that even when the polarity is inverted in the next frame, the ratio of the negative polarity (-) differs from that of the positive polarity (+), so that the ripple can be generated by distorting the common voltage Vcom. The common voltage ripple (Vcom ripple) causes flicker and horizontal crosstalk of the liquid crystal display device.

In order to improve the above-described common voltage ripple (Vcom ripple), it is possible to apply a method of compensating the generated ripple by providing a voltage compensating means such as OP-AMP in the common voltage portion 140 shown in Fig. 2 have. In this ripple cancellation method, a common voltage is applied to each pixel, and only the ripple component is fed back, and then the common voltage ripple is removed by applying the reverse voltage of the ripple component to the common voltage using OP-AMP or the like.

In addition, the polarity of the data voltage applied to each pixel line may be different to prevent the common voltage ripple from occurring without using a separate voltage compensating means. Hereinafter, referring to the drawings, The version driving method will be described as follows.

4 is a diagram illustrating a method of driving an in-version of a liquid crystal display device according to a second embodiment of the present invention.

As shown in the figure, the inversion driving method of the liquid crystal display according to the second embodiment of the present invention realizes a version method of a column in a color reproduction liquid crystal display, wherein one screen includes at least two logical first and And the first and second blocks include the same number of sub-pixel lines.

Here, it is preferable that the plurality of logical groups are excellent (2k, k is a natural number).

First, each sub-pixel line in the plurality of sub-pixel lines included in the first block corresponds to one of the three primary colors, and a unit pixel line PL _i (not shown) forming a unit pixel at a crossing point with a gate line Is composed of three sub-pixel lines, and the unit pixel lines adjacent to each other with respect to the unit pixel line PL _i have the same ratio of positive (+) and negative (-).

That is, the polarities of the data voltages are the same in the vertical direction and the polarities of the three sub-pixel human data voltages are different from each other between the neighboring unit pixel lines (PL ₁ to PL _i ).

The polarity of the unit pixel line included in the second block corresponding to the first block is inverted from that of the first block.

In detail, the polarities of the data voltages supplied to the liquid crystal panel are inverted for each sub-pixel line (SPL _{j + 1} , SPL _j ) (j is a natural number) in one block and for each frame. At this time, the polarities of the data voltages between the neighboring sub-pixels in the horizontal direction are inverted from each other. In addition, the polarities of the applied data voltages are the same in each unit pixel line (PL ₁ to PL _i ), and are inverted for each frame.

For example, as shown in FIG. 4, the first unit pixel line PL ₁ included in the first block may include first to third sub-pixel lines corresponding to R, G, and B pixels in the vertical direction When a positive (+) data voltage is applied to the first sub-pixel line, the data voltage of the first sub-pixel line and the inverted data voltage of the negative (-) are applied to the second sub-pixel line. In addition, the first unit pixel line (PL ₁₎ a second unit pixel line (PL ₂₎ adjacent to the are to have the same polarity.

Correspondingly, the fifth unit pixel line PL ₅ of the second block includes the 13th to 15th sub pixel lines corresponding to the R, G, and B pixels in the vertical direction, (-) data voltage is applied to the 14th sub-pixel line, and the data voltage of the positive polarity (+) is applied to the 14th sub-pixel line.

That is, in the liquid crystal panel divided into two logical blocks, when the polarity of the first block is repeated in the form of +, -, +, -, +, +, -, + The polarity of the second block is repeated in the form of "-, +, -, -, +, -, -, +, -, -, +, -".

Although not shown, all the polarities of the above-described unit data line PL _i and the sub data line are inverted in the next second frame.

Therefore, the unit data lines PL _i included in each block have the same polarity, and the sub data lines forming one unit data line PL _i have mutually inverted polarities between neighboring lines, Have opposite polarities.

According to such a polarity structure, when an observer perceives an image of the unit data line to move sideways, the first unit data line PL ₁ in the Mth frame has a high positive luminance (+ , The second unit data line PL _{2 in the} (M + 1) -th frame recognizes an image having a low luminance of negative polarity, so that images of the same luminance are not overlapped and a line dim .

In addition, the common voltage ripple caused by influencing the common voltage (Vcom) applied to each pixel is improved since the ratio is not uniformly distributed in the whole frame in a specific polarity.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

100: liquid crystal panel 110: timing controller
120: Gate driver 130: Data driver
140: Common voltage parts GL ₁ to GL _h : Gate line
DL ₁ to DL _i : data lines PL ₁ to PL _i : unit pixel lines
SPL ₁ to SPL _j : sub pixel line Vcom 1: first common voltage
Vcom2: second common voltage

Claims (7)

A method of driving a version which is a column of a liquid crystal display device including a unit pixel including a plurality of sub-pixels arranged in a matrix form,
Sequentially applying a gate driving signal to a gate line; And
Applying a data voltage having the same polarity to each unit pixel line in the horizontal direction in synchronization with the gate driving signal so that data voltages applied to the plurality of sub pixels included in one unit pixel line are inverted with respect to each other
Lt; / RTI >
The plurality of sub-pixel lines may include first to third sub-pixel lines adjacent to each other in the horizontal direction and displaying different colors,
The data voltage applied to the second sub pixel line is inverted from the polarity of the data voltage applied to the first and third sub pixel lines adjacent to each other,
The data voltages of the same polarity are applied to the plurality of sub-pixels arranged in each of the first to third sub-pixel lines
A method of driving an in-version of a liquid crystal display device. delete The method according to claim 1,
Wherein the first through third sub-pixel lines display R, G, and B colors, respectively. The method according to claim 1,
And the data voltage is inverted in all of the polarity of the next frame. The method according to claim 1,
Removing the common voltage ripple (Vcom ripple) applied to the plurality of sub-pixels through the voltage compensating means
Further comprising the steps of: controlling the inversion of the liquid crystal display device. The method according to claim 1,
The unit pixel lines in one frame are grouped into a plurality of logical blocks,
Wherein polarities of data voltages applied to the plurality of logical blocks are inverted from each other. The method according to claim 6,
Wherein the plurality of logical groups are excellent (2k, k is a natural number).

Images