WO2013170588A1

WO2013170588A1 - Common electrode voltage setting method and device

Info

Publication number: WO2013170588A1
Application number: PCT/CN2012/083715
Authority: WO
Inventors: 柳在健; 谢畅; 谷新
Original assignee: 京东方科技集团股份有限公司
Priority date: 2012-05-17
Filing date: 2012-10-29
Publication date: 2013-11-21
Also published as: CN102708821A; CN102708821B

Abstract

A common electrode voltage setting method and device make the picture flicker of a liquid crystal display minimum by adjusting a common voltage, and then achieve the optimization of picture image retention. The common electrode voltage setting method comprises: obtaining an optimal feedback voltage corresponding to a minimum image retention grade; according to gamma reference voltages of different grey scales and the optimal feedback voltage, obtaining first common electrode voltages of different grey scales; and according to the first common electrode voltages of different grey scales, obtaining the average value of the first common electrode voltages, and according to the average value of the first common electrode voltages, setting a common electrode voltage of a printed circuit board.

Description

Method and device for setting common electrode voltage

Embodiments of the present invention relate to a method and apparatus for setting a common electrode voltage. Background technique

Thin Film Transistor-Liquid Crystal Display (TFT-LCD) has excellent performance and is suitable for mass production, and has been widely used in various electronic products. With the continuous improvement of the liquid crystal display technology, the requirements for the display screen of the liquid crystal display are also increasing.

In the prior art, liquid crystal displays using the Twisted Nematic (TN) mode are mainly used to avoid flickering by adjusting the common voltage, thereby avoiding the generation of afterimages. For the TN mode display, the common voltage should be accurately adjusted to the midpoint of the positive and negative voltages of the pixel electrode to avoid flickering, thus avoiding image afterimage.

However, if the common voltage in the horizontal electric field mode is adjusted by adjusting the common voltage in the TN mode, the liquid crystal display still has a residual image. In the horizontal electric field mode, the afterimage optimization cannot be achieved by adjusting the common voltage by the above method. Summary of the invention

Embodiments of the present invention provide a method and apparatus for setting a common electrode voltage for achieving a minimum image flicker of a liquid crystal display by adjusting a common voltage in a horizontal electric field mode, thereby achieving an image residual image optimization.

A first aspect of the present invention provides a method for setting a common electrode voltage, including: acquiring an optimal feedback voltage corresponding to a lowest afterimage level; acquiring different gray levels according to gamma reference voltages and optimal feedback voltages of different gray levels a first common electrode voltage; obtaining an average value of the first common electrode voltage according to the first common electrode voltage of the different gray scales, and setting a common electrode voltage of the printed circuit board according to an average value of the first common electrode voltages.

A second aspect of the present invention provides a device for setting a common electrode voltage, comprising: an optimal feedback voltage acquisition unit, configured to acquire an optimal feedback voltage corresponding to a lowest afterimage level; a pole voltage acquisition unit, configured to acquire first common electrode voltages of different gray levels according to gamma reference voltages and optimal feedback voltages of different gray levels; and a first common electrode voltage average value obtaining unit, configured to The first common electrode voltage acquires an average value of the first common electrode voltage; and a printed circuit board setting unit configured to set a common electrode voltage of the printed circuit board according to an average value of the first common electrode voltage.

Embodiments of the present invention provide a method and apparatus for setting a common electrode voltage, which obtains an optimal feedback voltage corresponding to a lowest afterimage level, and acquires different gray levels according to gamma reference voltages of different gray levels and an optimal feedback voltage. The first common electrode voltage is obtained, and an average value of the first common electrode voltage is obtained, so that in the horizontal electric field mode, the screen flicker of the liquid crystal display can be minimized by adjusting the common voltage, thereby realizing the optimization of the image afterimage. DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below. It is obvious that the drawings in the following description relate only to some embodiments of the present invention, and are not intended to limit the present invention. .

1 is a schematic diagram of a method for setting a common electrode voltage according to an embodiment of the present invention; FIG. 2 is a schematic diagram of another method for setting a common electrode voltage according to an embodiment of the present invention; A schematic structural diagram of a setting device for a common electrode voltage;

FIG. 4 is a schematic structural diagram of still another apparatus for setting a common electrode voltage according to an embodiment of the present invention; FIG.

FIG. 5 is a schematic structural diagram of another apparatus for setting a common electrode voltage according to an embodiment of the present invention. detailed description

The technical solutions of the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings. It is apparent that the described embodiments are part of the embodiments of the invention, rather than all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the described embodiments of the present invention without departing from the scope of the invention are within the scope of the invention. Unless otherwise defined, technical terms or scientific terms used herein shall be of ordinary meaning as understood by those of ordinary skill in the art to which the invention pertains. The words "first", "second" and similar terms used in the specification and claims of the invention are not intended to indicate any order, quantity or importance, but are merely used to distinguish different components. Similarly, the words "a" or "an" do not denote a quantity limitation, but rather mean that there is at least one.

Embodiments of the present invention provide a method for setting a common electrode voltage. As shown in FIG. 1, the following steps are included.

101. Acquire an optimal feedback voltage corresponding to the lowest afterimage level.

For example, a plurality of display panels prepared according to the same specifications are selected, and the gamma reference voltage, the common electrode voltage, and the corresponding afterimage level values of the plurality of display panels are respectively measured at different times in the same gray scale.

For each of the plurality of panels, the feedback voltage at a certain gray level is obtained according to the measured gamma reference voltage and the common electrode voltage, and then the average of the feedback voltage is obtained according to the feedback voltage obtained under different gray levels. value. The average of the feedback voltage is considered to be the feedback voltage of the panel. The formula for calculating the feedback voltage of a panel at different gray levels is:

Where G _p , _m is the positive voltage of the gamma reference voltage at the gray scale of _m , G _n , _m is the negative voltage of the gamma reference voltage at the gray scale of m, and Vcom2 is the second common electrode voltage, the AVP, _m is the feedback voltage at the m gray level, and m represents a different gray level. The gray scales selected for the average value are, for example, nine gray scales uniformly distributed in the range of 0 to 255, and nine feedback voltages under the nine gray scales are obtained, and then an average value is obtained.

Usually for a panel, the feedback voltage at a certain gray level usually does not change, so the average value of the feedback voltage is usually constant; the afterimage level varies with the operating time of the panel. According to the afterimage level measured at different times, the panel with the lowest afterimage level is selected, and the average value of the feedback voltage of this panel is taken as the optimal feedback voltage of the display panel of this specification.

Exemplarily, 10 display panels are selected, and the corresponding residual image level values of the 10 panels in 1 hour, 12 hours, and 48 hours are respectively measured in the gray scale of 63 (gray scale range 0 to 255); The feedback voltages of the 10 panels were calculated from the gamma reference voltage and the common electrode voltage of the 10 panels, and the average value of the feedback voltages of the 10 panels was calculated therefrom. Measurement and calculation The results are shown in Table 1.

Table 1

According to Table 1, it can be known that when the gray level is 63, by looking at the residual image level values of the 10 panels under different test times, the panel A8B2 has the lowest afterimage level value at each test time, so the panel A8B2 is The average value of the feedback voltage is 0.410 as the optimum feedback voltage value.

It should be noted that, according to Table 1, and through certain calculations, the correlation coefficient between the residual image level and the average value of the feedback voltage in the same gray level and different test times can be known, as shown in Table 2.

Table 2

According to Table 2, the correlation coefficient is in the range of 0.16~0.49. In statistics, if the correlation coefficient is 0.16-0.49, it indicates that there is correlation. The higher the correlation coefficient, the stronger the correlation. This shows that there is a correlation between the feedback voltage and the afterimage level, so the afterimage level can be minimized by adjusting the feedback voltage.

It should be noted that, in the example, the afterimage level of 10 panels in the case where the gray scale is 63 is measured. However, it is also possible to measure the afterimage level values of the 10 panels of the other gray scales at different times, and use the average value of the feedback voltage corresponding to the panel with the lowest afterimage level value among the 10 panels as the optimal feedback voltage value. There is no limit to this. 102. Acquire first common electrode voltages of different gray levels according to gamma reference voltages of different gray levels and the optimal feedback voltage.

The formula for calculating the first common electrode voltage for different gray levels is:

Where G _p , _m is the positive voltage of the gamma reference voltage at m gray scale, G _n , _m is the negative voltage of the gamma reference voltage at m gray scale, AV _P1 is the optimal feedback voltage, V _{∞ ml} _m is the first common electrode voltage at m gray scale, and m represents a different gray scale.

103. Acquire a flat voltage of the first common electrode voltage according to the first common electrode voltage of the different gray scales.

After the first common electrode voltages of different gray levels are calculated in step 102, the calculated first common electrode voltages of different gray levels are averaged to obtain an average value of the first common electrode voltage, and the printed circuit board is The common electrode voltage of the set device) is set to the average value of the first common electrode voltage. This achieves the effect of preventing the generation of afterimages by adjusting the common electrode voltage in the horizontal electric field mode.

Embodiments of the present invention provide a method for setting a common electrode voltage, which obtains an optimal feedback voltage corresponding to a lowest afterimage level, and acquires different gray levels according to gamma reference voltages of different gray levels and an optimal feedback voltage. a common electrode voltage, an average value of the first common electrode voltage is obtained according to the first common electrode voltage of the different gray scale, and the common electrode voltage of the device is set by the average value. In the horizontal electric field mode, the picture of the liquid crystal display can be minimized by adjusting the common voltage, thereby optimizing the residual image of the picture.

As shown in Fig. 2, another embodiment of the present invention provides another method of setting a common electrode voltage, which includes the following steps.

201. Obtain a gamma reference voltage and a second common electrode voltage of different gray levels of the printed circuit board (ie, the set device).

It should be noted that the first common electrode voltage is a value obtained according to an optimal feedback voltage, and the average value of the first common electrode voltage is an optimum common electrode voltage to be set on the printed circuit board; however, the second common electrode The voltage is the common electrode voltage of the printed circuit board before the optimum common electrode voltage is set. 202. Acquire a feedback voltage of different gray levels of the printed circuit board according to the gamma reference voltage and the second common electrode voltage of the different gray levels.

It should be noted that the feedback voltages of different gray levels are determined by the gamma reference voltage and the second common electrode voltage of different gray scales of the printed circuit board.

The formula for calculating the feedback voltage of different gray levels of a printed circuit board is:

Where G _p , _m is the positive voltage of the gamma reference voltage at the gray scale of _m , G _n , _m is the negative voltage of the gamma reference voltage at the gray scale of m, and Vcom2 is the second common electrode voltage, the AVP, _m is the feedback voltage at the m gray level, and m represents a different gray level. In step 202, feedback voltages of different gray levels are calculated, and the calculated feedback voltages of different gray levels are averaged.

204. Acquire an optimal feedback voltage corresponding to the lowest afterimage level.

This is the same as step 101 and will not be described here.

205. Determine whether an average value of the feedback voltage is equal to the optimal feedback voltage.

The average value of the feedback voltages of the different gray levels obtained in step 203 is compared with the optimal feedback voltage obtained in step 204 to determine whether the average value of the feedback voltage is equal to the optimal feedback voltage.

If the average of the feedback voltages is not equal to the optimal feedback voltage, steps 206 and 207 are performed. If the average value of the feedback voltage is equal to the optimal feedback voltage, then the common electrode voltage of the printed circuit board is the optimum common electrode voltage and does not need to be set.

206. Acquire first common electrode voltages of different gray levels according to gamma reference voltages of different gray levels and the optimal feedback voltage.

In a case where the average value of the feedback voltage is not equal to the optimal feedback voltage, the first common electrode voltages of different gray levels are acquired according to the gamma reference voltages of different gray levels and the optimal feedback voltage. The process of obtaining the first common electrode voltages of different gray levels according to the gamma reference voltages of different gray levels and the optimal feedback voltage is the same as step 102, and is not described herein.

207. Acquire an average value of the first common electrode voltage according to the first common electrode voltage of different gray levels, and according to the first This step is the same as step 103 and will not be described here.

It should be noted that the sequence of the step 201 to the step 203 and the step 204 is not fixed. The step 204 may be performed after the step 201 to the step 203 or the step 201 to the step 203.

Taking the above method, an electric field is formed with the pixel electrode according to the set common electrode voltage to drive the liquid crystal for display.

Embodiments of the present invention provide a method for setting a common electrode voltage, which obtains an optimal feedback voltage corresponding to a minimum afterimage level, and acquires a gamma reference voltage and a second common electrode voltage of different gray scales of the printed circuit board, according to The gamma reference voltage and the second common electrode voltage of different gray levels are used to obtain feedback voltages of different gray levels, and the average value of the feedback voltage is obtained; whether the average value of the feedback voltage is equal to the optimal feedback voltage; if they are equal, there is no need to set Determining the common electrode voltage of the printed circuit; if not equal, acquiring the first common electrode voltage of different gray levels according to the gamma reference voltage of different gray levels and the optimal feedback voltage, according to the first common electrode voltage of different gray levels The average value of the first common electrode voltage is obtained, and the average value is set; thus, in the horizontal electric field mode, the screen flicker of the liquid crystal display can be minimized by adjusting the common voltage, thereby realizing the optimization of the image afterimage.

An embodiment of the present invention provides a device for setting a common electrode voltage. As shown in FIG. 3, the embodiment includes an optimal feedback voltage acquisition unit 301, a first common electrode voltage acquisition unit 302, and a first common electrode voltage average value acquisition unit 303. And a printed circuit board setting unit 304.

The optimal feedback voltage acquisition unit 301 is configured to obtain an optimal feedback voltage corresponding to the lowest afterimage level. The optimal feedback voltage is used to obtain the first common electrode voltage of different gray levels. The first common electrode voltage acquisition unit 302 can obtain the first common electrode voltages of different gray levels according to the following formula:

G„ + G _r

■- AV where G _p , _m is the positive voltage of the gamma reference voltage at m gray scale, G _n , _m is the negative voltage of the gamma reference voltage at m gray scale, AV _P1 is the optimal feedback voltage, V _∞ml , _m is the first common electrode voltage at m gray scale, and m represents different gray scales. The common electrode voltage acquires an average value of the first common electrode voltage. The printed circuit board setting unit 304 is configured to set a common electrode voltage of the printed circuit board (the set device) according to the average value of the first common electrode voltage.

In addition, the setting device of the common electrode voltage of the embodiment, as shown in FIG. 4, may further include: a gamma reference voltage and a second common electrode voltage acquiring unit 305, a feedback voltage acquiring unit 306, and a feedback voltage average value acquiring unit. 307 and judging unit 308.

The gamma reference voltage and the second common electrode voltage acquisition unit 305 are for acquiring the gamma reference voltage and the second common electrode voltage of the different gray scales of the printed circuit board.

The feedback voltage acquisition unit 306 is configured to calculate the gamma reference voltage and the second common according to the different gray levels

306 can obtain feedback voltages of different gray levels according to the following formula:

Where G _p , _m is a positive voltage of a gamma reference voltage at m gray scale, G _n , _m is a negative voltage of a gamma reference voltage at m gray scale, and V _∞m2 is a second common electrode voltage, Δν _Ρ , _m is the feedback voltage at the m gray scale, and m represents the different gray scale.

The feedback voltage average value obtaining unit 307 is configured to obtain an average value of the feedback voltages according to the feedback voltages of the different gray levels. equal. " : '' : ^ ^L , the first common electrode voltage obtaining unit 302 is configured to: according to the gamma reference of different gray scales, if the average value of the feedback voltage is not equal to the optimal feedback voltage The voltage and the optimal feedback voltage acquire first common electrode voltages of different gray levels.

Further, the setting means of the common electrode voltage of the present embodiment may further include an ending unit 309 as shown in FIG. The ending unit 309 is configured to end setting the common electrode voltage of the printed circuit board according to the average value of the feedback voltage of the determining unit 308 being equal to the optimal feedback voltage.

Embodiments of the present invention provide a device for setting a common electrode voltage, which obtains an optimal feedback voltage corresponding to a lowest afterimage level, and acquires different gray scales according to gamma reference voltages of different gray levels and an optimal feedback voltage. The first common electrode voltage determines an average value of the first common electrode voltage according to the first common electrode voltage of different gray levels, and sets the average value. In the horizontal electric field mode, the screen can be minimized by adjusting the common voltage, thereby realizing drawing. Optimization of the afterimage.

However, the apparatus of the above-described embodiment of the present invention is not limited to the horizontal electric field type liquid crystal display panel, and may be applied to a vertical electric field type liquid crystal display panel to perform common voltage setting.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims.

Claims

claims

1. A method for setting the common electrode voltage, including:

Obtain the optimal feedback voltage corresponding to the lowest afterimage level;

Obtain the first common electrode voltage of different gray levels according to the gamma reference voltage of different gray levels and the optimal feedback voltage;

The first common electrode voltage average value is obtained according to the first common electrode voltages of different gray scales, and then the common electrode voltage of the printed circuit board is set according to the first common electrode voltage average value.

2. The method according to claim 1, before obtaining the first common electrode voltage of different gray levels according to the gamma reference voltage of different gray levels and the optimal feedback voltage, further comprising:

Obtain the gamma reference voltage of the different gray levels and the second common electrode voltage of the printed circuit board; obtain the different gray levels of the printed circuit board according to the gamma reference voltage of the different gray levels and the second common electrode voltage. level feedback voltage;

3. The method according to claim 2, before obtaining the first common electrode voltage of different gray scales according to the gamma reference voltage of different gray scales and the optimal feedback voltage, the obtaining of the first common electrode voltage corresponding to the lowest afterimage level. After the optimal feedback voltage, it also includes:

Determine whether the average value of the feedback voltage is equal to the optimal feedback voltage;

When the average value of the feedback voltage is not equal to the optimal feedback voltage, the first common electrode voltages of different gray levels are obtained according to the gamma reference voltages of different gray levels and the optimal feedback voltage.

4. The method according to claim 3, wherein if the average value of the feedback voltage is equal to the optimal feedback voltage, the common electrode voltage of the printed circuit board is not set.

5. The method according to claim 2, wherein the gamma reference voltage according to the different gray scales and the second A is determined by .

The formula is:

G„ + G _r where, G _p , _m is the positive voltage of the gamma reference voltage under m gray level, G _n , _m is the negative voltage of the gamma reference voltage under m gray level, Vcom2 is the second common electrode voltage , the AVP, _m is obtained Feedback voltage under m gray scale, m represents different gray scales.

6. The method according to any one of claims 1 to 5, wherein the formula for obtaining the first common electrode voltage of different gray levels based on the gamma reference voltage and the optimal feedback voltage of different gray levels is:

Among them, G _p , _m is the positive voltage of the gamma reference voltage under m gray level, G _n , _m is the negative voltage of the gamma reference voltage under m gray level, AV _P1 is the optimal feedback voltage, V _∞ml , _m is the first common electrode voltage under m gray scale, and m represents different gray scales.

7. A common electrode voltage setting device, including:

The optimal feedback voltage acquisition unit is used to obtain the optimal feedback voltage corresponding to the lowest afterimage level; the first common electrode voltage acquisition unit is used to obtain different gray levels according to the gamma reference voltage of different gray levels and the optimal feedback voltage. The first common electrode voltage;

A first common electrode voltage average value acquisition unit, configured to obtain an average value of the first common electrode voltage according to the first common electrode voltages of different gray scales;

A printed circuit board setting unit, configured to set the common electrode voltage of the printed circuit board according to the average value of the first common electrode voltage.

8. The device according to claim 7, further comprising:

A gamma reference voltage and second common electrode voltage acquisition unit, used to acquire the gamma reference voltage and the second common electrode voltage of the different gray scales of the printed circuit board;

A feedback voltage acquisition unit, configured to acquire the average value of the feedback voltage according to the gamma reference voltage of the different gray scales and the second common feedback voltage average value, based on the feedback voltages of the different gray scales;

The judgment unit is used to determine whether the average value of the feedback voltage is equal to the optimal feedback voltage; the first common electrode voltage acquisition unit is specifically configured to determine whether the average value of the feedback voltage is equal to the optimal feedback voltage. If they are not equal, the first common electrode voltages of different gray levels are obtained according to the gamma reference voltages of different gray levels and the optimal feedback voltage.

9. The device according to claim 8, further comprising:

An ending unit configured to end setting the common electrode voltage of the printed circuit board if the average value of the feedback voltage is equal to the optimal feedback voltage according to the judging unit.

10. The device according to claim 8, wherein the feedback voltage average obtaining unit obtains feedback voltages of different gray levels according to the following formula:

Factory + C

y

2

Wherein, G _p , _m is the positive voltage of the gamma reference voltage under m gray level, G _n , _m is the negative voltage of the gamma reference voltage under m gray level, Vcom2 is the second common electrode voltage, and the AVP, _m is the obtained feedback voltage at m gray level, and m represents different gray levels.

1 1. The device according to any one of claims 7 to 10, wherein the first common electrode voltage acquisition unit acquires the first common electrode voltages of different gray levels according to the following formula: 2 Where, G _p , _m is the positive voltage of the gamma reference voltage under m gray level, G _n , _m is the negative voltage of the gamma reference voltage under m gray level, AV _P1 is the optimal feedback voltage, V _∞ml , _m is m gray level The first common electrode voltage under , m represents different gray levels.