JP2008164667A - Liquid crystal display device and driving method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which drives an auxiliary capacity line while typically fixing the potential of a common electrode, the liquid crystal display device being free of a bright point in spite of a short circuit between a pixel electrode and the auxiliary capacity line. <P>SOLUTION: A video signal S(m) as a voltage signal applied to a video signal line varies to a predetermined voltage value between 0 and 4V corresponding to the luminance of a pixel, and a common potential Vcom is 2V as its midpoint voltage; and a reference base potential (center) of an auxiliary capacity line drive signal Cs(n) is set equal to the common potential Vcom, and a pixel electrode potential of an image formation section P(n, m) is varied from the base potential to 7V or -3V. Even if a short-circuit defect between the pixel electrode and auxiliary capacity line occurs, no bright point is displayed nearly throughout a period wherein the potential of the auxiliary capacity line is equal to the common potential Vcom to improve the display quality of the display device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an active matrix liquid crystal display device using a switching element such as a thin film transistor and a driving method thereof, and more specifically, a liquid crystal display device that drives an auxiliary capacitance line by changing a voltage applied to the auxiliary capacitance line, and the method thereof The present invention relates to a driving method.

  A display unit of a general conventional active matrix liquid crystal display device includes a plurality (N) of scanning signal lines GL (1) to GL (N) and a plurality (M) of intersections with the plurality of scanning signal lines. ) Video signal lines SL (1) to SL (M) and a plurality (N × M) of matrix signals arranged corresponding to the intersections of the plurality of scanning signal lines and the plurality of video signal lines. Pixel forming portions P (1,1) to P (N, M), and each pixel forming portion has a pixel electrode and an electrode ("common electrode") as shown in FIG. Liquid crystal capacitance (also referred to as “pixel capacitance”) Clc. Each pixel electrode is provided with two video signal lines SL (m) and SL (m + 1) so as to sandwich it, and the video signal line SL (m) is connected to the pixel electrode via the TFT 10. Has been.

  Further, in this liquid crystal display device, as shown in FIG. 1 to be described later, a plurality (N) of auxiliary capacitance lines CsL (n) are formed in parallel with each scanning signal line GL (n), and each pixel In the formation portion P (n, m), an auxiliary capacitance Ccs is formed between the pixel electrode and the auxiliary capacitance line CsL (n).

  In the active matrix type liquid crystal display device as described above, in each pixel formation portion P (n, m), when the TFT 10 connected to the pixel electrode is in an on state (conductive state), the video signal line SL (m) When a voltage is applied via the TFT 10 and the TFT 10 is turned off (cut off), the applied voltage is held in the pixel capacitor Clc (and the auxiliary capacitor Ccs), and a pixel is displayed according to the held voltage ( n = 1, 2,..., N; m = 1, 2,.

  Here, in this conventional liquid crystal display device, after the TFT 10 is turned off, the voltage applied to the auxiliary capacitance line CsL (n) is changed, whereby the common electrode (applied with the constant voltage Vcom) is changed. The reference pixel electrode potential is changed. Such a potential change will be described in detail with reference to FIG.

  FIG. 8 is a waveform diagram of various signals in a conventional liquid crystal display device. As shown in FIG. 8, the video signal S (m), which is a voltage signal applied to the video signal line SL (m), has a predetermined voltage value corresponding to the luminance of the pixel from 0V to 4V. Yes. In the figure, the voltage value of the video signal S (m) is a voltage value corresponding to the maximum luminance (white luminance). Thus, by setting the lowest voltage in the video signal S (m) to 0V, the power consumption can be suppressed as a whole.

  Here, since it is necessary to perform AC driving in order to prevent deterioration of the liquid crystal layer with time, when the potential Vcom of the common electrode is fixed, the common potential Vcom is set to the midpoint voltage (in the change width) of the video signal. Often. This is because the potential of the pixel electrode based on the potential of the common electrode can be changed to an alternating current. Again, the common potential Vcom is set to 2V.

  However, in order to maximize the transmittance of the liquid crystal layer in a normally black liquid crystal display device, an applied voltage of about 4 to 5 V is usually required. Therefore, the applied voltage is in the range of ± 2V with the above configuration, which is not sufficient. In this respect, a sufficient applied voltage can be obtained with a configuration in which the video signal S (m) is changed from 0 V to 10 V, for example, but the power consumption is greatly increased. Therefore, in this conventional liquid crystal display device, the potential of the pixel electrode is changed by driving the auxiliary capacitance line CsL (n). That is, as can be seen from the connection relationship shown in FIG. 2 described later, the potential of the pixel electrode Epix is equal to the pixel capacitance value with respect to the potential change of the auxiliary capacitance line CsL (n) when the common electrode Ecom is used as a reference. It changes according to the ratio of the auxiliary capacity to the sum of the capacity value. For example, as shown in FIG. 8, when the pixel capacitance value Clc: auxiliary capacitance value Ccs = 2: 3, a signal given to the auxiliary capacitance line (hereinafter, this signal is referred to as “auxiliary capacitance line drive signal”) Cs (n) Changes by 5V, the potential of the pixel electrode Epix changes by 3V.

  Therefore, as shown in FIG. 8, the pixel electrode potential of the pixel formation portion P (n, m) is 4 V when the scanning signal G (n) changes from the active state (turning on the TFT 10) to the inactive state. However, it is further increased by 3V to 7V due to the potential change of the storage capacitor line drive signal Cs (n) thereafter. Therefore, since the common potential Vcom is 2V, the voltage applied to the liquid crystal layer at this time is 5V. Such a potential change is the case where pixel display is performed with the highest luminance (white luminance) as described above, but the same is true when pixel display is performed with the lowest luminance (black luminance) not shown. That is, the pixel electrode potential of the pixel formation portion P (n, m) in this case is held at 0 V when the scanning signal G (n) is in an inactive state, but the subsequent auxiliary capacitance line drive signal Cs. As a result of the increase of 3V due to the potential change in (n), 3V is obtained. Therefore, since the common potential Vcom is 2V, the voltage applied to the liquid crystal layer at this time is 1V. Since this voltage value is less than the threshold voltage value at which the liquid crystal molecules are driven, the light transmittance of the liquid crystal layer is 0, which is an appropriate value for black display. The above operation is the same in the pixel electrode potential of the pixel formation portion P (n + 1, m) in the next row and the pixel formation portion P (n, m) in the next frame whose polarity is inverted.

In this way, the potential type of the auxiliary capacitance line is set to 0V, 5V, and -5V so that the potential changes to 5V or -5V with 0V as a reference according to the polarity of the pixel electrode. As a result, the power consumption can be suppressed as a whole. Conventional liquid crystal display devices that perform the operation of driving the storage capacitor line in this way are disclosed in, for example, Patent Documents 1 to 3 below.
JP-A-1-88496 Japanese Patent Laid-Open No. 2-157815 JP 2001-83943 A

  However, in the above-mentioned conventional liquid crystal display device of the normally black type, when a short circuit failure occurs between the pixel electrode and the auxiliary capacitance line, the display defect is more conspicuous than the conventional liquid crystal display device that drives the auxiliary capacitance line together with the common electrode. Occurs.

  That is, in the conventional liquid crystal display device that drives the auxiliary capacitance line together with the common electrode, even if the pixel electrode and the auxiliary capacitance line are short-circuited, a potential difference between the pixel electrode and the common electrode does not occur. It is only displayed. Therefore, it is difficult to visually recognize the display defect and it is difficult for the user to feel uncomfortable. In such a short circuit, the gate insulating film is rarely lost in the manufacturing process in which the auxiliary capacitance line is provided in the same layer as the scanning line so that an electrostatic capacitance (auxiliary capacitance) is formed through the pixel electrode and the gate insulating film. In order to improve display quality, it is important that no noticeable display failure occurs even when such a short circuit failure occurs.

  On the other hand, in the above-described conventional liquid crystal display device in which only the auxiliary capacitance line is driven while fixing the potential of the common electrode (normally black type), a short circuit failure between the pixel electrode and the auxiliary capacitance line occurs. There is always a potential difference between the electrode and the auxiliary capacitance line. For example, if the common potential Vcom is 2V, a potential difference of 2V is generated in most periods where the potential of the auxiliary capacitance line is 0V. Therefore, due to this short circuit failure, a bright spot (with a predetermined luminance) is displayed in the short circuit portion in most periods. Since this bright spot is easy to be visually recognized and uncomfortable for the user, the display quality of the apparatus is lowered.

  Therefore, according to the present invention, in the liquid crystal display device in which the potential of the common electrode is typically fixed and the auxiliary capacitance line is driven, the bright spot is not generated or is hardly visually recognized even by a short circuit failure between the pixel electrode and the auxiliary capacitance line. An object is to provide a liquid crystal display device.

According to a first aspect of the present invention, there is provided a video signal line driving circuit for driving a plurality of video signal lines for transmitting a plurality of video signals corresponding to image signals given from the outside of the apparatus in order to display a predetermined image; A scanning signal line driving circuit for driving a plurality of scanning signal lines intersecting with the video signal line, and an auxiliary capacitance line driving circuit for driving a plurality of auxiliary capacitance lines arranged correspondingly along the plurality of scanning signal lines And a plurality of pixel forming portions arranged in a matrix along the plurality of video signal lines and the plurality of scanning signal lines, and a common electrode for applying a common potential to the plurality of pixel forming portions. A liquid crystal display device,
Each of the plurality of pixel forming portions is an electrode connected to a corresponding video signal line among the plurality of video signal lines, and a predetermined auxiliary capacitance is formed between the corresponding auxiliary capacitance line, Including a pixel electrode in which liquid crystal is interposed between the common electrode,
The auxiliary capacitance line driving circuit selects the plurality of auxiliary capacitance lines at a value close to the potential of the common electrode during the whole period or a period excluding a predetermined period, and the corresponding scanning signal line is selected by the scanning signal line driving circuit. At a predetermined time after the operation, the driving is performed so as to change the potential difference between the corresponding pixel electrode and the common electrode.

According to a second invention, in the first invention,
The auxiliary capacitance line driving circuit has a first potential that is greater than or equal to a potential of the common electrode at a predetermined time after a scanning signal line corresponding to the plurality of auxiliary capacitance lines is selected by the scanning signal line driving circuit. By driving from a potential of 2 to a predetermined base potential in the vicinity of the potential of the common electrode, driving is performed so as to vary the potential difference between the corresponding pixel electrode and the common electrode.

According to a third invention, in the second invention,
The storage capacitor line driving circuit determines the base potential so that a difference between the base potential and the potential of the common electrode is equal to or lower than a threshold voltage of the liquid crystal.

According to a fourth invention, in the second invention,
The auxiliary capacitance line driving circuit is characterized in that the base potential is determined so as to substantially match the potential of the common electrode.

A fifth invention is the fourth invention,
The power source further includes a power source that applies the common potential to the common electrode and is capable of adjusting a value of the common potential.
The auxiliary capacitance line driving circuit determines the base potential based on the common potential supplied from the power source.

A sixth invention is the second invention, wherein:
A power supply that provides a first power supply potential that is near the potential of the common electrode and that is greater than the potential and a second power supply potential that is less than the potential;
An adjustment unit that adjusts the potential of the common electrode between the first and second power supply potentials supplied from the power supply, and applies the adjusted potential to the common electrode as the common potential;
The storage capacitor line driving circuit determines the base potential based on one of the first and second power supply potentials supplied from the power supply.

According to a seventh invention, in the first invention,
The auxiliary capacitance line driving circuit has a predetermined first potential in the vicinity of the potential of the common electrode at a predetermined time after a scanning signal line corresponding to the plurality of auxiliary capacitance lines is selected by the scanning signal line driving circuit. The potential difference between the corresponding pixel electrode and the common electrode is changed by changing from the second potential to the predetermined second potential in the vicinity of the common electrode potential, or from the second potential to the first potential. It is characterized by being driven.

In an eighth aspect based on the seventh aspect,
The storage capacitor line driving circuit is configured such that a difference between the first potential and the potential of the common electrode and a difference between the second potential and the potential of the common electrode are both equal to or lower than a threshold voltage of the liquid crystal. The first and second potentials are determined.

According to a ninth invention, in the seventh invention,
A power supply that provides a first power supply potential that is near the potential of the common electrode and that is greater than the potential and a second power supply potential that is less than the potential;
An adjustment unit that adjusts the potential of the common electrode between the first and second power supply potentials supplied from the power supply, and applies the adjusted potential to the common electrode as the common potential;
The storage capacitor line driving circuit determines at least one of the first and second potentials based on at least one of the first and second power source potentials supplied from the power source.

According to a tenth aspect of the present invention, a plurality of video signal lines for transmitting a plurality of video signals corresponding to image signals given from the outside of the apparatus to display a predetermined image, and a plurality of crossing the plurality of video signal lines. Scanning signal lines, a plurality of auxiliary capacitance lines arranged along the plurality of scanning signal lines, a common electrode for applying a common potential, the plurality of video signal lines, and the plurality of scanning signals. A predetermined auxiliary capacitance is formed between the plurality of video signal lines connected to the corresponding video signal line and the corresponding auxiliary capacitance line, and arranged in a matrix along the line. A method of driving a liquid crystal display device including a plurality of pixel formation portions including pixel electrodes with liquid crystal interposed therebetween,
A video signal line driving step for driving the plurality of video signal lines;
A scanning signal line driving step for driving the plurality of scanning signal lines;
An auxiliary capacitance line driving step for driving the plurality of auxiliary capacitance lines,
In the auxiliary capacitance line driving step, the plurality of auxiliary capacitance lines are selected to have a value near the potential of the common electrode during the entire period or a period excluding a predetermined period, and a corresponding scanning signal line is selected in the scanning signal line driving step. At a predetermined time after being performed, the driving is performed so as to change the potential difference between the corresponding pixel electrode and the common electrode.

  According to the first aspect of the present invention, in the liquid crystal display device that drives the auxiliary capacitance line with the potential of the common electrode typically fixed (or not greatly fluctuated), the auxiliary capacitance line is set for the entire period or for a predetermined period. The liquid crystal display device is driven at a value close to the potential of the common electrode during a period excluding, so that a bright spot does not occur in the short-circuited portion or is hardly visually recognized even if a short-circuit failure occurs between the pixel electrode and the auxiliary capacitance line. it can.

  According to the second aspect of the present invention, the base potential serving as a reference among the potentials of the auxiliary capacitance lines that change in three stages is set to a value near the potential of the common electrode, whereby the pixel electrode and the auxiliary capacitance line are short-circuited. Even when a defect occurs, the display quality of the display device can be improved because the bright spot is not displayed or is hardly visually recognized in most periods in which the potential of the storage capacitor line is the base potential.

  According to the third aspect of the invention, since the difference between the base potential and the common electrode potential is equal to or lower than the threshold voltage of the liquid crystal, the bright spot is not displayed (visually) in most periods, and the display quality of the display device is improved. Can be increased.

  According to the fourth aspect of the present invention, since the base potential and the potential of the common electrode substantially coincide with each other, the bright spots are not completely displayed in most periods, and the display quality of the display device can be improved.

  According to the fifth aspect, since the common electrode potential and the base potential are supplied from the same power source that can be adjusted, the power supply circuit can be shared and the configuration of the power supply circuit is simplified. Can do. Further, by making the base potential the same as, for example, the common potential appropriately adjusted for each device, the display quality can be improved in any liquid crystal display device regardless of the degree of adjustment.

  According to the sixth aspect, since the base potential is determined based on one of the first and second power supply potentials, it is not necessary to newly generate a base potential, and the configuration of the power supply circuit is simplified. can do. Since the first and second power supply potentials are often used for fine adjustment of the common electrode potential, the difference between the first or second power supply potential and the common electrode potential is the liquid crystal threshold voltage. In many cases, the bright spot is not displayed (visually) in most periods, and the display quality of the display device can be improved.

  According to the seventh aspect of the present invention, the short-circuit failure between the pixel electrode and the auxiliary capacitance line is caused by setting the potential of each auxiliary capacitance line that changes in two steps to a value near the potential of the common electrode. In addition, since the bright spots are not displayed or are hardly visually recognized in all periods, the display quality of the display device can be improved.

  According to the eighth aspect, since the difference between the first or second potential and the potential of the common electrode is equal to or lower than the threshold voltage of the liquid crystal, the bright spot is not displayed (visually) and the display quality of the display device is displayed. Can be increased.

  According to the ninth aspect, since at least one of the first and second potentials is determined based on at least one of the first and second power supply potentials, it is not necessary to generate at least one potential, and the power supply circuit The configuration can be simplified. Since the first and second power supply potentials are often used for fine adjustment of the common electrode potential, the difference between the first or second power supply potential and the common electrode potential is the liquid crystal threshold voltage. In many cases, the bright spot is not displayed (visually) in this case, and the display quality of the display device can be improved.

  According to the tenth aspect, the same effect as that of the first aspect can be achieved in the method for driving the liquid crystal display device.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the display unit is a vertical alignment method and is configured to be normally black, and as a driving method, voltages applied to the liquid crystal portion of the pixel formation unit are reversed for each adjacent row. A so-called line inversion driving method is adopted in which the polarity is reversed and the polarity is reversed every frame.

<1. First Embodiment>
<1.1 Overall Configuration and Operation of Liquid Crystal Display>
FIG. 1 is a block diagram showing the overall configuration of an active matrix liquid crystal display device according to a first embodiment of the present invention. The liquid crystal display device includes a display control circuit 200, a source driver (video signal line drive circuit) 300, a gate driver (scanning signal line drive circuit) 400, and a storage capacitor line drive circuit 500, and a display unit 600. And.

  The display unit 600 includes a plurality (M) of video signal lines SL (1) to SL (M), a plurality (N) of scanning signal lines GL (1) to GL (N), and an auxiliary capacitance line CsL. (1) to CsL (N), a plurality of video signal lines SL (1) to SL (M), and a plurality of scanning signal lines GL (1) to GL (N) provided along the plurality. (M × N) pixel forming portions are included. In the following description, a pixel forming portion provided near the intersection (in the drawing, near the lower right of the intersection) in association with the intersection of the scanning signal line GL (n) and the video signal line SL (m) is denoted by the reference symbol “P”. (N, m) ". FIG. 2 shows an equivalent circuit of the pixel formation portion P (n, m) in the display portion 600 of the present embodiment.

  As shown in FIG. 2, each pixel forming portion P (n, m) has a gate terminal connected to the scanning signal line GL (n) or the adjacent scanning signal line GL (n + 1) and passes through the intersection. TFT 10 which is a switching element having a source terminal connected to the video signal line SL (m) or the video signal line SL (m + 1) adjacent thereto, the pixel electrode Epix connected to the drain terminal of the TFT 10, and the plurality Common electrode Ecom provided in common in the pixel formation portions P (i, j) (i = 1 to N, j = 1 to M), and the plurality of pixel formation portions P (i, j) (i = 1 to N, j = 1 to M), and a liquid crystal layer serving as an electro-optic element sandwiched between the pixel electrode Epix and the common electrode Ecom.

  Each pixel forming portion P (n, m) displays one of red (R), green (G), and blue (B), and has the same color as shown in FIG. Is formed along the video signal lines SL (1) to SL (M) and the direction along the scanning signal lines GL (1) to GL (N). Are arranged in the order of RGB.

  In each pixel forming portion P (n, m), a liquid crystal capacitor (also referred to as “pixel capacitor”) Clc is formed by the pixel electrode Epix and the common electrode Ecom that faces the pixel electrode Epix across the liquid crystal layer. Each pixel electrode Epix is provided with two video signal lines SL (m) and SL (m + 1) so as to sandwich the pixel electrode Epix, and the video signal line SL (m) is connected to the pixel electrode Epix via the TFT 10. It is connected to the.

  Further, auxiliary capacitance lines CsL (n) are formed in parallel with the respective scanning signal lines GL (n), and in each pixel formation portion P (n, m), the pixel electrode Epix and the auxiliary capacitance line CsL (n) A storage capacitor Ccs is formed between the two.

  The display control circuit 200 receives a display data signal DAT and a timing control signal TS sent from the outside, and controls a digital image signal DV, a source start pulse signal SSP for controlling the timing of displaying an image on the display unit 600, a source A clock signal SCK, a latch strobe signal LS, a gate start pulse signal GSP, a gate clock signal GCK, and an auxiliary capacitance line control signal Scs are output.

  The source driver 300 receives the digital image signal DV, the source start pulse signal SSP, the source clock signal SCK, and the latch strobe signal LS output from the display control circuit 200, and each pixel forming unit P (n, In order to charge the pixel capacitor Clc of m), the driving video signals S (1) to S (M) are applied to the video signal lines SL (1) to SL (M). At this time, the source driver 300 sequentially holds the digital image signal DV indicating the voltage to be applied to each of the video signal lines SL (1) to SL (M) at the timing when the pulse of the source clock signal SCK is generated. . The held digital image signal DV is converted into an analog voltage at the timing when the pulse of the latch strobe signal LS is generated.

  Such D / A conversion is performed by a D / A conversion circuit (and a gradation voltage generation circuit) included in the source driver 300. The D / A conversion circuit generates an analog voltage corresponding to each display gradation by, for example, dividing a reference voltage for generating a gradation voltage given from the outside of the source driver 300. The analog voltage generated by the D / A conversion circuit is applied simultaneously to all the video signal lines SL (1) to SL (M) as a driving video signal. That is, in the present embodiment, the line sequential driving method is adopted as the driving method of the video signal lines SL (1) to SL (M).

  Based on the gate start pulse signal GSP and the gate clock signal GCK output from the display control circuit 200, the gate driver 400 scans the scanning signal lines GL (1) to GL (N) with an active scanning signal G (1). ... G (N) are sequentially applied.

  The auxiliary capacitance line driving circuit 500 is based on the auxiliary capacitance line control signal Scs output from the display control circuit 200 and based on potentials supplied from power supply circuits (not shown) to the auxiliary capacitance lines CsL (1) to CsL (N). The storage capacitor line drive signals Cs (1) to Cs (N) whose potential changes in three stages are sequentially applied. The auxiliary capacitance line control signal Scs includes, for example, a start pulse signal and a clock signal corresponding to the gate start pulse signal GSP and the gate clock signal GCK, and a signal indicating the timing of polarity inversion (or the potential selection). Yes.

  As can be seen from the connection relationship shown in FIG. 2, when the voltage applied to these auxiliary capacitance lines CsL (1) to CsL (N) changes, the potential of the pixel electrode Epix is based on the common electrode Ecom. When the potential of the auxiliary capacitance line CsL (n) changes, it changes according to the ratio of the auxiliary capacitance to the sum of the pixel capacitance value and the auxiliary capacitance value. Thus, the potential difference between the common potential Vcom and the pixel electrode in each pixel formation portion can be increased in white display (in other words, the voltage of the pixel electrode can be increased). The waveform of this signal will be described later.

  As described above, the driving video signal is applied to the video signal lines SL (1) to SL (M), the scanning signal is applied to the scanning signal lines GL (1) to GL (N), and the auxiliary signals are applied. An image is displayed on the display unit 600 by applying the storage capacitor line drive signal to the capacitor lines CsL (1) to CsL (N). The common electrode Ecom is supplied with a predetermined voltage by a power supply circuit (not shown) and is held at the common potential Vcom. Next, potential changes of various signals will be described with reference to FIG.

<1.2 Waveforms of various signals>
FIG. 3 is a waveform diagram of various signals in the present liquid crystal display device. As shown in FIG. 3, the video signal S (m), which is a voltage signal applied to the video signal line SL (m), has a predetermined voltage value corresponding to the luminance of the pixel from 0V to 4V, that is, positive polarity. In this case, the voltage value corresponding to the lowest luminance (black luminance) is set to 0 V, the voltage value corresponding to the highest luminance (white luminance) is set to 4 V, and in the case of negative polarity, the voltage corresponding to the lowest luminance (black luminance). The voltage value is 4V, the voltage value corresponding to the maximum luminance (white luminance) is 0V, and the voltage value is in the range of ± 4V. Thus, by setting the lowest voltage in the video signal S (m) to 0V, the power consumption can be suppressed as a whole. In the figure, the voltage value of the video signal S (m) is a voltage value corresponding to the maximum luminance (white luminance) (4 V in the case of positive polarity and 0 V in the case of negative polarity).

  As described above, since the liquid crystal layer needs to be driven by alternating current in order to prevent deterioration over time, when the potential Vcom of the common electrode is typically fixed, the common potential Vcom is equal to (in the change width of the video signal). ) The midpoint voltage is set. This is because the potential of the pixel electrode based on the potential of the common electrode can be changed to an alternating current. Again, the common potential Vcom is set to 2V.

  However, in order to maximize the transmittance of the liquid crystal layer in a normally black liquid crystal display device, an applied voltage of about 4 V to 5 V is usually required. By driving the line CsL (n), the potential of the pixel electrode is changed. That is, when the common electrode Ecom is used as a reference, the potential of the pixel electrode Epix changes according to the ratio of the auxiliary capacitance to the sum of the pixel capacitance value and the auxiliary capacitance value with respect to the potential change of the auxiliary capacitance line CsL (n). Therefore, if the ratio between the pixel capacitance value Clc and the auxiliary capacitance value Ccs is set to 2: 3, a signal (hereinafter, this signal is referred to as an “auxiliary capacitance line drive signal”) Cs (n ) Changes by 5V, the potential of the pixel electrode Epix changes by 3V.

  The storage capacitor line drive signal Cs (n) has its potential falling at the rising timing of the scanning signal G (n−1) not shown in FIG. 3, and the rising edge of the scanning signal G (n + 1) shown in FIG. Based on the storage capacitor line control signal Scs, the storage capacitor line drive circuit 500 generates the signal so as to rise at the falling timing. Of course, the potential change of the storage capacitor line drive signal Cs (n) is not limited to the above-described mode, and may be any waveform that rises after the scan signal G (n) falls.

  Here, in the present liquid crystal display device, unlike the conventional liquid crystal display device, the potential of each auxiliary capacitance line changes up or down by 5 V or −5 V from the reference voltage based on 2 V depending on the polarity of the pixel electrode. As described above, the types of potentials are set to 2V, 7V, and -3V. As described above, the reference potential (hereinafter referred to as “base potential”) among the potentials of the auxiliary capacitance lines is set to 2V, so that the auxiliary capacitance line is more than the conventional case where the base potential is set to 0V. Has a demerit that a large amount of power is required for driving.

  However, even if a short circuit failure occurs between the pixel electrode and the auxiliary capacitance line by setting the base potential of each auxiliary capacitance line to 2 V which is the same as the common potential Vcom, the potential of the auxiliary capacitance line is set. In most of the period when the voltage is 0 V, the potential difference between the common electrode and the auxiliary capacitance line does not occur. Therefore, even with this short circuit failure, the bright spot is not displayed in most periods when the potential of the auxiliary capacitance line is the base potential, and the user is not uncomfortable. Such a short-circuit failure may occur due to a rare loss of the gate insulating film as described above. Therefore, even if a short-circuit failure occurs, the display quality of the display device is not caused by the above-described configuration. Can be increased.

  Further, by setting the base potential of each auxiliary capacitance line to 2 V, which is the same as the common potential Vcom, it is possible to share the power supply circuit that generates the common potential, thereby simplifying the configuration of the power supply circuit and improving the efficiency. Since a power source can be formed well, power consumption can be reduced.

  Further, although FIG. 3 does not consider any change in the potential of the pixel electrode due to the potential change of the scanning signal line according to the parasitic capacitance between the corresponding scanning signal line and the pixel electrode, it is actually common in accordance with this change. In many cases, the potential Vcom needs to be individually adjusted for each liquid crystal display device, for example, by a common potential adjusting unit (not shown) made of a variable resistor. In this case, by making the base potential of each auxiliary capacitance line the same as the common potential (output from the common potential adjusting unit), the display quality can be improved in any liquid crystal display device regardless of the degree of adjustment. Can do.

  When taking into account the change in the pixel electrode potential due to the change in the potential of the scanning signal line in accordance with the parasitic capacitance between the scanning signal line and the pixel electrode, for example, due to the fall of the pulse in the scanning signal G (n). When the potential of the pixel electrode Epix in the pixel formation portion P (n, m) decreases by 0.3 V, the set potential is set to 6.5 V and −3.5 V in consideration of the change due to the parasitic capacitance. Good. Such a change caused by the parasitic capacitance will be specifically described in the third embodiment.

As shown in FIG. 3, the pixel electrode potential of the pixel forming portion P (n, m) is 4 V when the scanning signal G (n) is changed from the active state (turning on the TFT 10) to the inactive state. Although it is held, it is further increased by 3V to 7V due to the potential change in the subsequent auxiliary capacitance line drive signal Cs (n). Therefore, since the common potential Vcom is 2V, the voltage applied to the liquid crystal layer at this time is 5V. By holding this applied voltage until the display time in the next frame,
Pixel display is performed with a luminance corresponding to the applied voltage.

  As shown in FIG. 3, such an operation is performed by the pixel forming portion P (n + 1, m) of the next row whose polarity is inverted by the above-described line inversion driving method and the pixel forming portion P of the next frame whose polarity is inverted. The same applies to (n, m).

<1.3 Effects of First Embodiment>
As described above, in this embodiment, the reference (center) base potential among the potentials of the auxiliary capacitance lines that change in three stages is set to be the same as the common potential Vcom, so that the pixel electrode and the auxiliary potential are set. Even when a short-circuit failure with the capacitor line occurs, the luminance is bright in most periods in which the potential of the auxiliary capacitor line is the same as the common potential Vcom, that is, in most periods except for a predetermined period in which the potential of the auxiliary capacitor line is not the base potential. The dots are not displayed, and the display quality of the display device can be improved.

<2. Second Embodiment>
<2.1 Device Configuration and Operation>
FIG. 4 is a block diagram showing the overall configuration of an active matrix liquid crystal display device according to the second embodiment of the present invention. As in the case of the first embodiment shown in FIG. 1, the liquid crystal display device includes a display control circuit 200, a source driver (video signal line driving circuit) 300, a gate driver (scanning signal line driving circuit) 400, and an auxiliary device. In addition to the drive control unit including the capacitive line drive circuit 520 and the display unit 600, the device further includes a common potential adjustment unit 700 and a power supply unit 800, which are not illustrated in the first embodiment. Note that the common potential adjustment unit 700 and the power supply unit 800 are normally provided in the configuration of the first embodiment, but are illustrated in the present embodiment because they have features.

  As described above, this embodiment is different from the configuration of the first embodiment in that the common potential adjustment unit 700 and the power supply unit 800 are provided, and the operation of the auxiliary capacitance line driving circuit 520 in which the potential of the output signal is different. Unlike the other components, which are the same as those in the first embodiment, the same components are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 4, the power supply unit 800 has terminals for outputting voltages of 1V and 3V, both of which are supplied to the common potential adjustment unit 700, and one of them is supplied (here, a voltage of 3V). This is given to the auxiliary capacitance line driving circuit 520. Since the circuit configuration of the power supply unit 800 that is such a constant voltage source is well known, detailed description thereof is omitted. The power supply unit 800 outputs other voltages than the above voltages and voltages to be applied to other components, which are well known and will not be described.

  The common potential adjusting unit 700 is composed of a three-terminal variable resistor. The terminals at both ends thereof are supplied with voltages of 1 V and 3 V, and the central terminal has an appropriate common potential according to the individual difference of the display device. A voltage value in the vicinity of 2V adjusted so as to be output is output.

  The storage capacitor line drive circuit 520 has a waveform similar to that of the storage capacitor line drive signal Cs (n) shown in FIG. 3, and the storage capacitor line drive signal Cs (n) having a different voltage value is applied to each storage capacitor line. give. Unlike the case of the first embodiment, the base potential in the storage capacitor line drive signal Cs (n) is 3 V supplied from the power supply unit 800, and the storage capacitor line potential is ± It changes to 8V and -2V with a potential difference of 5V.

As described above, the three-stage voltages are higher by 1 V than in the first embodiment, and the operation of each part is the same as in the first embodiment. Is different from the common potential Vcom having a base potential of 2V. However, even when the base potential of each auxiliary capacitance line is different from the common potential Vcom as described above, if the difference is about 1 V, a short circuit failure between the pixel electrode and the auxiliary capacitance line occurs. Even in this case, no bright spot is generated in most periods when the potential of the storage capacitor line is the base potential. This will be described with reference to FIG.

  FIG. 5 is a diagram illustrating the relationship between the voltage applied to the liquid crystal layer and the light transmittance thereof. In the figure, the vertical axis represents the light transmittance [%], and the horizontal axis represents the applied voltage [V]. Referring to FIG. 5, it can be seen that even when a voltage of up to about 1 V is applied to the liquid crystal layer, almost no light is transmitted (the light transmittance hardly changes from 0%). Thus, the maximum applied voltage to the liquid crystal where the light transmittance is about 0% and the change from 0% is hardly visible is called a liquid crystal threshold voltage. Therefore, when the difference between the base potential and the common potential Vcom is within about 1 V, which is the liquid crystal threshold voltage, no bright spot is generated in most periods, as in the case of 0 V. The relationship shown in FIG. 5 is an example, and these values vary depending on the composition of the liquid crystal, for example, when the applied voltage at which the light transmittance is 100% is 4 V. In general, the light transmittance hardly changes below a predetermined threshold voltage.

  Further, since the storage capacitor line drive circuit 520 receives a voltage (here, 3V) corresponding to the base potential directly from the power supply unit 800, not from the common potential adjustment unit 700, the auxiliary capacitance line drive circuit 520 is not illustrated which is normally provided in the common potential adjustment unit 700. The load on the buffer is not increased. Furthermore, since it is not necessary to newly generate a voltage corresponding to the base voltage, the configuration of the power supply unit 800 can be simplified.

<2.2 Effects of Second Embodiment>
As described above, in the present embodiment, the reference (center) base potential among the potentials of the respective auxiliary capacitance lines that change in three stages is within about 1 V from the common potential Vcom (transmission of the liquid crystal layer). By setting the potential to a level where the rate hardly changes, even if a short circuit failure occurs between the pixel electrode and the auxiliary capacitance line, a bright spot is displayed in most periods when the potential of the auxiliary capacitance line is the base potential. Therefore, the display quality of the display device can be improved.

  In addition, since the storage capacitor line driving circuit 520 directly receives the voltage to be supplied from the power supply unit 800 to the common potential adjustment unit 700 as a voltage corresponding to the base potential from the power supply unit 800, the load applied to the buffer of the common potential adjustment unit 700 In addition, the configuration of the power supply unit 800 can be simplified.

<3. Third Embodiment>
<3.1 Device Configuration and Operation>
FIG. 6 is a block diagram showing the overall configuration of an active matrix liquid crystal display device according to the third embodiment of the present invention. As in the case of the second embodiment shown in FIG. 4, the liquid crystal display device includes a display control circuit 200, a source driver (video signal line driving circuit) 300, a gate driver (scanning signal line driving circuit) 400, and an auxiliary device. A drive control unit including a capacitor line drive circuit 530, a display unit 600, a common potential adjustment unit 700, and a power supply unit 800 are provided. FIG. 7 is a waveform diagram of various signals in the present liquid crystal display device.

  As described above, in the present embodiment, the operation of the auxiliary capacitance line driving circuit 530 having a different output signal waveform and the like and the voltage applied thereto are different from the configuration of the second embodiment, and other components are the second. Since this is the same as the case of the embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 6, the power supply unit 800 has terminals that output voltages of 1V and 3V as in the case of the second embodiment, but the voltage from both terminals is a common potential adjustment unit. This is applied not only to 700 but also to the auxiliary capacitance line driving circuit 520.

  Unlike the case of the first and second embodiments, the storage capacitor line driving circuit 530 outputs the storage capacitor line potential Cs (n) shown in FIG. 7 where the potential changes in two stages. As shown in FIG. 7, the potential Cs (n) of the auxiliary capacitance line is 1 V or 3 V respectively applied from the two terminals of the power supply unit 800, and the potential of the auxiliary capacitance line has these two values. It changes to take alternately. As described above, since the storage capacitor line drive circuit 520 receives the same voltage as the voltage supplied to the common potential adjustment unit 700 from the power supply unit 800, it is not necessary to newly generate a voltage to be supplied to the storage capacitor line drive circuit 530. Therefore, the configuration of the power supply unit 800 can be simplified.

  Note that, as shown in FIG. 7, the potential of the storage capacitor line drive signal Cs (n) changes after a predetermined period from the falling timing of the scanning signal G (n). This timing and FIG. There is no limitation on the waveform or the like, and it may be changed after the scanning signal G (n) falls.

  Next, the video signal S (m) will be described. As shown in FIG. 7, the video signal S (m), which is a voltage signal applied to the video signal line SL (m), has a predetermined voltage value corresponding to the luminance of the pixel from 0V to 5V. Yes. Thus, by setting the lowest voltage in the video signal S (m) to 0V, the power consumption can be suppressed as a whole. In the figure, the voltage value of the video signal S (m) is a voltage value (0 V or 5 V) corresponding to the maximum luminance (white luminance).

  As described above, even in the case of the present embodiment, AC driving for preventing deterioration of the liquid crystal layer with time is necessary, but the common potential Vcom is a midpoint voltage (in the change width) of the video signal. It is not set to 5V, and the common potential Vcom is set to 2V. This is because a change in the pixel electrode potential due to a change in the potential of the scanning signal line in accordance with the parasitic capacitance between the corresponding scanning signal line and the pixel electrode is taken into consideration. Hereinafter, this point will be described in detail.

  As shown in FIG. 7, the pixel electrode potential of the pixel formation portion P (n, m) is 5 V when the scanning signal G (n) first enters the active state (turns on the TFT 10). Thereafter, when the scanning signal G (n) becomes inactive (that is, when the pulse falls), the voltage decreases by 0.5 V and is held at 4.5V. This is because when the potential of the scanning signal line GL (n) falls as described above, the pixel electrode potential decreases due to the parasitic capacitance between the scanning signal line and the pixel electrode.

  Thereafter, as in the case of the first embodiment, the potential of the pixel electrode is changed by changing the storage capacitor line drive signal Cs (n). However, unlike the case of the first embodiment, an applied voltage of about 4 V is sufficient here to maximize the transmittance of the liquid crystal layer, and the ratio between the pixel capacitance value Clc and the auxiliary capacitance value Ccs is here. It shall be set to 1: 3. Therefore, when the potential of the auxiliary capacitance line drive signal Cs (n) changes by 2V, the potential of the pixel electrode Epix of the pixel formation portion P (n, m) is held at 6V which is changed from 4.5V by 1.5V. It will be.

  Thereafter, similarly in the next frame, the pixel electrode potential of the pixel formation portion P (n, m) becomes 0 V when the scanning signal G (n) is next activated, and then the scanning signal G ( When n) becomes inactive (that is, when the pulse falls), the voltage decreases by 0.5 V and is held at -0.5 V. Similarly, since the potential of the auxiliary capacitance line drive signal Cs (n) changes from 3V to −2V, the potential of the pixel electrode of the pixel formation portion P (n, m) decreases from −0.5V to 1.5V− It will be held at 2V. As described above, the pixel electrode potential of the pixel formation portion P (n, m) is eventually AC driven within a range of ± 4 V with the common potential Vcom as the midpoint potential. Such an operation is the same in the pixel formation portion P (n + 1, m) of the next row whose polarity is inverted by the above-described line inversion driving method.

  As described above, when the voltage of the storage capacitor line drive signal does not coincide with the common potential Vcom which is 2 V as in the case of the second embodiment, the difference is about 1 V which is the liquid crystal threshold voltage. No bright spot occurs even when a short circuit failure occurs between the pixel electrode and the auxiliary capacitance line. This is as described with reference to FIG.

<3.2 Effects of Third Embodiment>
As described above, in the present embodiment, the potential of each auxiliary capacitance line that changes in two steps is set to a potential that does not fall within about 1 V from the common potential Vcom (the transmittance of the liquid crystal layer hardly changes). Even when a short circuit failure occurs between the pixel electrode and the auxiliary capacitance line, bright spots are not displayed over the entire period when the potential of the auxiliary capacitance line is equal to or lower than the liquid crystal threshold voltage, and the display quality of the display device is improved. Can do.

  In addition, since the potential of each auxiliary capacitance line that changes in two steps is made the same as the potential supplied from the power supply unit 800 to the common potential adjustment unit 700, a voltage to be newly applied to the auxiliary capacitance line driving circuit 530 is generated. This is unnecessary, and the configuration of the power supply unit 800 can be simplified.

<4. Modification>
In each of the above embodiments, the common potential Vcom is fixed to a constant potential. However, the common potential Vcom does not necessarily need to be constant and may vary. For example, in the second embodiment, when the potential difference between the changing common potential Vcom and the base potential is within about 1 V (the transmittance of the liquid crystal layer hardly changes), the pixel electrode and the auxiliary capacitance line Even when a short-circuit failure occurs, bright points are not displayed in most of the period when the potential of the storage capacitor line is the base potential, and the display quality of the display device can be improved.

  The base potential in the second embodiment and the two types of potentials of the auxiliary capacitance line drive signal in the third embodiment are both within about 1 V from the common potential Vcom, that is, the transmittance of the liquid crystal layer changes substantially. However, these potentials may be separated from the common potential Vcom by more than about 1V. In this case, since the transmittance of the liquid crystal slightly changes, a bright spot having a predetermined luminance is displayed as a result. However, since the luminance does not increase, the display device does not give a great discomfort to the user. Display quality can be improved to some extent.

  In the third embodiment, only one of the potentials of the auxiliary capacitance lines that change in two steps may be set to a potential that does not differ from the common potential Vcom by about 1V. In this case, the transmissivity of the liquid crystal slightly changes in a half period. As a result, a bright spot having a predetermined brightness is displayed in the half period, but the brightness does not increase and the display period is also halved. The display quality of the display device can be improved to some extent without giving the user a great discomfort.

  In the second embodiment, the auxiliary capacitance line driving circuit 520 is configured to directly receive a voltage to be supplied from the power supply unit 800 to the common potential adjustment unit 700 from the power supply unit 800 as a voltage corresponding to the base potential. As long as a voltage having a difference within about 1 V from Vcom is received, the voltage to be applied to the common potential adjustment unit 700 is not necessarily required. Even in this case, there is an effect that the load applied to the buffer of the common potential adjusting unit 700 is not increased.

  In the third embodiment, the potential of the auxiliary capacitance line that changes in two steps is directly received from the power supply unit 800 in the same manner as the voltage to be supplied from the power supply unit 800 to the common potential adjustment unit 700. The configuration may be such that only one type of potentials is received from the power supply unit 800 with the same voltage as that to be applied to the common potential adjustment unit 700. Even in such a case, it is not necessary to newly generate the potential, so that the configuration of the power supply unit 800 can be simplified as long as that.

1 is a block diagram illustrating an overall configuration of a liquid crystal display device according to a first embodiment of the present invention. It is a circuit diagram which shows the equivalent circuit of the pixel formation part in the said embodiment. It is a wave form chart of various signals in the above-mentioned embodiment. It is a block diagram which shows the whole structure of the liquid crystal display device which concerns on the 2nd Embodiment of this invention. It is a figure which shows the relationship between the voltage applied to the liquid-crystal layer in the said embodiment, and the transmittance | permeability of the light. It is a block diagram which shows the whole structure of the liquid crystal display device which concerns on the 3rd Embodiment of this invention. It is a wave form chart of various signals in the above-mentioned embodiment. It is a wave form diagram of various signals in the conventional liquid crystal display device.

Explanation of symbols

10 ... TFT (switching element)
DESCRIPTION OF SYMBOLS 200 ... Display control circuit 300 ... Source driver 400 ... Gate driver 500, 520, 530 ... Auxiliary capacitance line drive circuit 600 ... Display part 700 ... Common electric potential adjustment part 800 ... Power supply part Ecom ... Common electrode Epix ... Pixel electrode GL (n) ... Scanning signal lines (n = 1 to N)
G (n) ... scanning signal (n = 1 to N)
CsL (n): Auxiliary capacitance line (n = 1 to N)
Cs (n): Auxiliary capacitance line drive signal (n = 1 to N)
SL (m): Data signal line (m = 1 to M)
P (n, m): Pixel formation portion (n = 1 to N, m = 1 to M)

Claims (10)

A video signal line driving circuit for driving a plurality of video signal lines for transmitting a plurality of video signals corresponding to an image signal given from the outside of the apparatus for displaying a predetermined image; and intersecting the plurality of video signal lines A scanning signal line driving circuit for driving the plurality of scanning signal lines, an auxiliary capacitance line driving circuit for driving a plurality of auxiliary capacitance lines arranged corresponding to the plurality of scanning signal lines, and the plurality of videos. A liquid crystal display device comprising: a plurality of pixel formation portions arranged in a matrix along a signal line and the plurality of scanning signal lines; and a common electrode that applies a common potential to the plurality of pixel formation portions. ,
Each of the plurality of pixel forming portions is an electrode connected to a corresponding video signal line among the plurality of video signal lines, and a predetermined auxiliary capacitance is formed between the corresponding auxiliary capacitance line, Including a pixel electrode in which liquid crystal is interposed between the common electrode,
The auxiliary capacitance line driving circuit selects the plurality of auxiliary capacitance lines at a value close to the potential of the common electrode during the whole period or a period excluding a predetermined period, and the corresponding scanning signal line is selected by the scanning signal line driving circuit. A liquid crystal display device that is driven so as to change a potential difference between a corresponding pixel electrode and the common electrode at a predetermined time point after being applied.   The auxiliary capacitance line driving circuit has a first potential that is greater than or equal to a potential of the common electrode at a predetermined time after a scanning signal line corresponding to the plurality of auxiliary capacitance lines is selected by the scanning signal line driving circuit. 2. The driving according to claim 1, wherein the potential difference between the corresponding pixel electrode and the common electrode is changed by changing from a potential of 2 to a predetermined base potential in the vicinity of the potential of the common electrode. Liquid crystal display device.   3. The liquid crystal according to claim 2, wherein the storage capacitor line driving circuit determines the base potential so that a difference between the base potential and the potential of the common electrode is equal to or lower than a threshold voltage of the liquid crystal. Display device.   The liquid crystal display device according to claim 2, wherein the storage capacitor line driving circuit determines the base potential so as to substantially match the potential of the common electrode. The power source further includes a power source that applies the common potential to the common electrode and is capable of adjusting a value of the common potential.
The liquid crystal display device according to claim 4, wherein the auxiliary capacitance line driving circuit determines the base potential based on the common potential supplied from the power source. A power supply that provides a first power supply potential that is near the potential of the common electrode and that is greater than the potential and a second power supply potential that is less than the potential;
An adjustment unit that adjusts the potential of the common electrode between the first and second power supply potentials supplied from the power supply, and applies the adjusted potential to the common electrode as the common potential;
The liquid crystal display device according to claim 2, wherein the auxiliary capacitance line driving circuit determines the base potential based on one of the first and second power supply potentials supplied from the power supply.   The auxiliary capacitance line driving circuit has a predetermined first potential in the vicinity of the potential of the common electrode at a predetermined time after a scanning signal line corresponding to the plurality of auxiliary capacitance lines is selected by the scanning signal line driving circuit. The potential difference between the corresponding pixel electrode and the common electrode is changed by changing from the second potential to the predetermined second potential in the vicinity of the common electrode potential, or from the second potential to the first potential. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is driven.   The storage capacitor line driving circuit is configured such that a difference between the first potential and the potential of the common electrode and a difference between the second potential and the potential of the common electrode are both equal to or lower than a threshold voltage of the liquid crystal. The liquid crystal display device according to claim 7, wherein the first and second potentials are determined. A power supply that provides a first power supply potential that is near the potential of the common electrode and that is greater than the potential and a second power supply potential that is less than the potential;
An adjustment unit that adjusts the potential of the common electrode between the first and second power supply potentials supplied from the power supply, and applies the adjusted potential to the common electrode as the common potential;
8. The auxiliary capacitance line driving circuit determines at least one of the first and second potentials based on at least one of the first and second power source potentials applied from the power source. The liquid crystal display device described. A plurality of video signal lines for transmitting a plurality of video signals corresponding to image signals given from the outside of the apparatus for displaying a predetermined image; a plurality of scanning signal lines intersecting the plurality of video signal lines; A plurality of storage capacitor lines arranged to correspond along the plurality of scanning signal lines, a common electrode for applying a common potential, a matrix along the plurality of video signal lines and the plurality of scanning signal lines A predetermined auxiliary capacitance is formed between the corresponding auxiliary capacitance line and an electrode connected to the corresponding video signal line among the plurality of video signal lines, and liquid crystal is interposed between the common electrode and the common electrode. A method of driving a liquid crystal display device including a plurality of pixel forming portions including pixel electrodes,
A video signal line driving step for driving the plurality of video signal lines;
A scanning signal line driving step for driving the plurality of scanning signal lines;
An auxiliary capacitance line driving step for driving the plurality of auxiliary capacitance lines,
In the auxiliary capacitance line driving step, the plurality of auxiliary capacitance lines are selected to have a value near the potential of the common electrode during the entire period or a period excluding a predetermined period, and a corresponding scanning signal line is selected in the scanning signal line driving step. A driving method of a liquid crystal display device, wherein the driving is performed so as to change a potential difference between a corresponding pixel electrode and the common electrode at a predetermined time point after being applied.

Images