WO2013152591A1 - Display device and driving method thereof - Google Patents

Description

 Display device driving method and display device

 Embodiments of the present invention relate to a driving method of a display device and a display device. Background technique

 Thin Film Transistor-Liquid Crystal Display (TFT-LCD) has a small size, low power consumption, and no radiation, and has dominated the current flat panel display market. With the rapid development of TFT-LCD technology, large-sized and low-cost high-load products such as large-sized liquid crystal televisions (TVs) have emerged. The emergence of such products puts higher demands on picture quality.

 In the normal operation, the TFT-LCD of the prior art opens the scan lines corresponding to one frame in a row-by-row manner. When a scan line is turned on, the data signals are input to the respective pixel units of the scan line through the data lines. However, there is usually a coupling capacitor between the data line and the common electrode, and the design of the high-load product results in a larger coupling area between the data line and the common electrode, that is, a larger coupling capacitance. Therefore, the common electrode is affected by the coupling when writing data per scan line, thereby causing a coupling phenomenon, that is, the voltage of the common electrode is deflected as the polarity and intensity of the transmitted data are changed. If the polarity and intensity of the transmitted data change asymmetrically, the voltage of the common electrode will change and the picture quality will be problematic. For example, in the 1+2 dot (dot) inversion mode, a few lines of green appear above the original gray screen. As shown in Fig. 1, on the screen displayed by the conventional TFT-LCD, a green area 12 may appear above the gray area 11.

 The so-called "1+2 dot inversion mode" means that in each column of pixel units, except for the first one, the polarity of the data signals of the remaining pixel units is every two inversions (the two consecutive polarities are the same, The next two polarities are opposite to the last two polarities), while the polarity of the first pixel unit is opposite to the second pixel, for example the polarity in a column of pixels is "+ - - + + ... ... "or" - + + -- ... ... " . Summary of the invention

Embodiments of the present invention provide a driving method and a display device for improving the picture quality of a display device for stabilizing the voltage of the common electrode, thereby improving the stability of the picture. An embodiment of the present invention provides a driving method for improving picture quality of a display device, the display device including a display area, a gate driver, and a source driver, the display area including a plurality of scanning lines, a plurality of data lines, and a common electrode, the scan signal outputted from the gate driver sequentially turns on the scan line of the display area, and the data signal output from the source driver is input to each pixel of the scan line through the data line when one scan line is opened In the unit, a coupling capacitor exists between the data line and the common electrode. The method includes: inputting a setting data signal into the data line in a field blanking time before a first scanning line corresponding to a frame of picture is opened, and using the data line corresponding to the scanning line corresponding to the one frame of the frame The coupling of the data lines to the common electrode.

 Another embodiment of the present invention provides a display device including a display area, a gate driver, and a source driver. The display area includes a plurality of scan lines, a plurality of data lines and a common electrode, the gate driver is configured to output a scan signal to each scan line, and the source driver is configured to pass through the scan line when each scan line is opened The data line outputs a data signal to each pixel unit of the scan line, and a coupling capacitor exists between the data line and the common electrode. The source driver is further configured to input a set data signal to the data line before the first blank line corresponding to the first scan line is opened, to cancel the scan line corresponding to the one frame. The coupling of the data lines to the common electrode.

 The embodiment of the present invention can enable the common electrode to obtain a driving complementary to the fluctuation of the data signal of the one frame when the frame is turned on, and stabilize the voltage of the common electrode, thereby improving the stability of the picture and improving the screen shield. 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 picture quality problem occurring in the prior art;

 2 is a schematic flow chart of a specific embodiment of a method according to the present invention;

 Figure 3 is a schematic diagram of the voltage fluctuation of the common electrode;

 4 is a schematic diagram of eliminating fluctuations of a common electrode in the present invention;

FIG. 5 is a schematic structural view of an embodiment of a display device according to the present invention. detailed description

 The technical solutions of the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings of the embodiments of the present invention. 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 the ordinary meaning 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 present invention do not denote 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. The words "including" or "comprising", etc., are intended to mean that the elements or objects preceding "including" or "comprising" are intended to encompass the elements or Component or object. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "Down", "Left", "Right", etc. are only used to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationship may also change accordingly.

 Generally, the display area of the display device is defined by a plurality of intersecting data lines and gate lines. When progressive scan is performed for display, the gate lines are turned on by scanning one by one, so each row of gate lines can also be called a scan line. During the scan, the scan always starts from the upper left corner of the image, moving horizontally forward, and the scan point moves down at a certain rate. The turn-on signal of each row of pixel cells is transmitted by the same gate line, and the signal transmission on this gate line is transmitted from left to right. When the scan point reaches the right edge of the image, the scan point quickly returns to the left side, and the second line scan is started again under the first line. The return process between the lines is called horizontal blanking, that is, from the end of the line. The time interval between scanning to the start of the next line of scanning. A complete image scan signal consisting of all rows of signal sequences separated by a horizontal blanking interval, referred to as a frame. After scanning the scanned frame, return to the upper left corner of the image from the lower right corner of the image to start a new frame scan. The time interval between the end of one frame scan and the start of the next frame scan is called vertical blanking, also known as field blanking.

There is a coupling capacitor between the data line and the common electrode. Therefore, in order to stabilize the voltage of the common electrode and provide the stability of the picture, the embodiment of the present invention provides a drive for improving the picture quality of the display device. Method. The display device includes a gate driver and a source driver, and the scan signal output from the gate driver sequentially turns the scan lines row by row, wherein the set number of scan lines corresponds to one frame. When the scan line is turned on, a data signal output from the source driver is input into a pixel unit of the scan line through a data line, and a coupling capacitor exists between the data line and the common electrode.

 The method includes: inputting a set data signal into the data line in a field blanking time before a first scan line corresponding to a frame of picture is opened, to cancel the data line when the scan line corresponding to the one frame picture is opened Coupling of the common electrode.

 Inputting a set data signal to the data line before the blanking time before the first scanning line is turned on, so that the common electrode can obtain the voltage compensation before the one-frame picture starts scanning, then the whole process of scanning the one-frame picture The medium common electrode is not adversely affected by changes in the input data signal voltage.

 Illustratively, the set data signal is opposite to the data signal in which the coupling of the data lines of all columns in the one frame picture to the common electrode cannot be cancelled.

 For example, in the screen of the l+2dot inversion mode, the setting data signal may be a data signal of the first scanning line corresponding to the one frame of the picture. Thus, the field blanking time is exactly the same as the data signal transmitted in the data line when the first scanning line is turned on. If the data line is changed in the data line when the second scan line and the third scan line are turned on, and the voltage of the first line scan line data signal and the voltage of the changed data signal are relative to the rated voltage of the common electrode. Complementary, then the effect of the field blanking time and the data signal of the first scanning line and the data signals of the second scanning line and the third scanning line on the common electrode cancel each other, bringing an overall polarity and strength agreement to the common electrode; That is, the common electrode is not affected by the voltage change of the data signal, so that the voltage of the common electrode is kept stable.

 An embodiment of the method of the present invention will be described in detail below with reference to FIG.

 In this embodiment, the common electrode has a rated voltage of, for example, 6 volts, the voltage of the first scan line data signal is, for example, 4 volts, and the voltages of the second scan line and the third scan line data signal are, for example, 8 volts, that is, The voltage of one scan line data signal and the voltage of the second scan line and the third scan line data signal are complementary with respect to the nominal voltage of the common electrode. Thus, the driving method for improving the picture quality of the display device provided by the embodiment of the present invention includes the following steps.

 Step 201: Input a data signal of the first scan line into the data line in a field blanking time before the first scan line corresponding to one frame of the picture is turned on.

Step 202: Open the first scan line, and input the data line number into the pixel unit of the scan line. That is, a progressive scan is started to perform display of the frame picture.

 Step 203: Determine whether the scan line is the last scan line of the one frame picture. If yes, go to step 205, otherwise go to step 204.

 Step 204: Open the next scan line for data signal input, and then return to step 203. Step 205: The process ends. At this point, one frame of picture is displayed on the screen of the display device.

 After the last scanning line scan is completed, the corresponding data signals are stored in the pixel units of all the scanning lines corresponding to the one frame picture, and a complete picture of one frame is displayed in the display area. Here, the data signal of the first scan line is input to the data line at the field blanking time to ensure the field blanking time and the influence of the data signal of the first scan line and the data signals of the second scan line and the third scan line on the common electrode. They cancel each other and bring the overall polarity and strength of the common electrode into agreement, even if the common electrode is not affected by the voltage change of the data signal, thereby providing display picture stability.

 Figure 3 is a schematic diagram of the voltage fluctuation of the common electrode.

 Referring to Figure 3, assuming that the common electrode has a rated voltage of 6 volts, the voltage in the bright region differs from the rated voltage of the common electrode by 0.5 volts, and the voltage in the dark region differs from the rated voltage of the common electrode by 5 volts, where "+", "-" represents the polarity of the data signal corresponding to the last line of the blanking time, that is, the polarity of the data signal of the first scanning line. The polarity of the two lines is the same. In the following, the previous six columns of pixels are taken as an example. As shown in the figure, all pixels of the field blanking time are in a bright area, the first three columns of the first scanning line are bright areas, and the fourth, fifth, and sixth columns of pixels are dark. The first three columns of pixels of the second scan line and the third scan line are dark areas, and the pixels of columns 4, 5, and 6 are bright areas. From the point of view of the column, and considering the change in polarity, the voltage changes by 5.5 volts when alternating between bright and dark areas. It can be seen from the waveform diagrams of the first six columns of pixel voltages that the voltage changes in the first column and the second column cancel each other, and the voltage changes in the fourth column and the fifth column cancel each other out, and the voltage change in the third column and the portion in the sixth column The voltage changes cancel each other out, but the first voltage change in column 6 cannot be cancelled, which will have a certain coupling effect on the common electrode, as shown in the rightmost voltage waveform in the figure.

For the voltage waveform phenomenon of the common electrode in FIG. 3, the bright and dark areas of the field of the blanking time are changed to be the same as the light and dark areas of the first scanning line, as shown in FIG. Similarly, the meaning of the dark area and the bright area is the same as that of FIG. "+" and "-" respectively represent the polarity of the data signal corresponding to the last line of the field blanking time, and also the polarity of the data signal of the first scanning line. The polarities of the two lines are the same. From Figure 4, the first voltage change in column 6 of Figure 3 is eliminated, thereby eliminating the coupling effect on the common electrode voltage such that the voltage of the common electrode maintains its nominal voltage. By It can be seen that in the one frame picture, all the data lines of the column have a coupling effect on the common electrode, and the part of these coupling effects that cannot be cancelled easily causes the fluctuation of the common electrode. Therefore, a signal opposite to a portion of the coupling of the data lines of the columns to the common electrode that cannot be cancelled is set to be within a field blanking time before the first scanning line corresponding to the one frame picture is opened. The data signal can cancel the fluctuation caused by the coupling effect of the data line on the common electrode when the scan line corresponding to the one frame picture is opened.

 FIG. 5 is a schematic structural view of an embodiment of a display device according to the present invention.

 Referring to FIG. 5, a display device according to an embodiment of the present invention includes a display area 51 including a scan line (gate line) 53 and a data line 54. The display device further includes a gate driver 52 for outputting a scan signal disposed outside the display area, and a source driver 55 for outputting a data signal to each of the pixel units on the scan line 53 through the data line 54 when the scan line 53 is turned on. , the common electrode 57. A coupling capacitor 56 is present between the data line 54 and the common electrode 57.

 In the display device of the embodiment, the source driver 55 is further configured to input a set data signal into the data line 54 for the field blanking time before the first scan line corresponding to the one frame of the screen is turned on. The coupling effect of the data line 54 on the common electrode 57 when the scan line 53 corresponding to the one-frame picture is turned on is eliminated.

 Illustratively, the set data signal is opposite to the data signal in which the coupling of the data lines 54 of all columns in the one frame of the picture to the common electrode 57 cannot be cancelled. For example, in the screen of the l+2dot inversion mode, the setting data signal may be a data signal of the first scanning line corresponding to the one frame of the picture.

 When the display device performs the screen display, the common electrode 57 obtains a drive complementary to the fluctuation of the frame data signal when the frame is turned on, so that the common electrode 57 is not or less affected by the signal fluctuation in the data line 54. influences. Since the voltage of the common electrode 57 is stabilized, the display screen stability of the display device is obtained, and the picture quality is effectively improved.

As can be seen from the above description, in the process of improving the picture quality of the display device, in the process of improving the picture quality of the display device, the setting data signal is input to the data line in the field blanking time before the first scanning line corresponding to the one frame picture is opened. The coupling effect of the data line on the common electrode when the scan line corresponding to the one frame picture is turned on is cancelled. Therefore, in the embodiment of the present invention, the common electrode can obtain the driving complementary to the fluctuation of the data signal of the one frame when the frame is turned on, and stabilize the voltage of the common electrode, thereby improving the stability of the picture and improving the picture quality. The spirit and scope of the invention. The scope of the invention is defined by the appended claims.

Claims

Claim What is claimed is: 1. A driving method of a display device, the display device comprising a display area, a gate driver and a source driver, the display area comprising a plurality of scanning lines, a plurality of data lines and a common electrode, from the gate driver The output scan signal opens the scan lines of the display area row by row, and the data signals output from the source driver when one scan line is turned on are input into the respective pixel units of the scan line through the data lines, the data lines and the common A coupling capacitor is disposed between the electrodes, and the method includes: inputting a set data signal into the data line to cancel a scan corresponding to the one frame of the field before the first scan line corresponding to the one frame is opened. The coupling of the data lines to the common electrode when the row is open.  The method according to claim 1, wherein said setting data signal is opposite to a data signal in which a coupling effect of said data lines of said all columns in said one frame picture to said common electrode cannot be cancelled.  The method according to claim 1, wherein in the screen of the 1+2 dot inversion mode, the setting data signal includes a data signal corresponding to the first scanning line corresponding to the one frame of the frame.  4. A display device comprising: a display area, a gate driver, and a source driver; wherein the display area comprises a plurality of scan lines, a plurality of data lines and a common electrode, and the gate driver is configured to output a scan signal to Each of the scan lines, the source driver is configured to output a data signal to each pixel unit of the scan line through the data line when each scan line is turned on, and a coupling capacitor exists between the data line and the common electrode , among them,  The source driver is further configured to input a set data signal to the data line before the first blank line corresponding to the first scan line is opened, to cancel the scan line corresponding to the one frame. The coupling of the data lines to the common electrode.  The display device according to claim 4, wherein the setting data signal is opposite to a data signal in which the coupling of the data lines of all the columns in the one frame picture to the common electrode cannot be cancelled.  The display device according to claim 4, wherein in the 1+2 dot inversion mode, the setting data signal includes a data signal of a first scanning line corresponding to the one frame picture.