JP2009244287A - Liquid crystal display and method of driving liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display of excellent display quality by avoiding contrast deterioration and occurrence of vertical stripe, and to provide a method of driving the liquid crystal display. <P>SOLUTION: The liquid crystal display includes a control means CNT for controlling a display panel DP and an illumination means BL so as to light the illumination means in a third period continued from a second period, performing writing of video signals in the second period continued from the first period and performing writing of non-video signals in a first period, in one frame period. Each of display pixels PX includes a liquid crystal capacity Clc generated by a voltage applied between a pair of electrodes PE, CE and an auxiliary capacity Cst coupled to the liquid crystal capacity Clc. The control means CNT includes an auxiliary capacity electrode potential supply means for changing potential of an auxiliary capacity electrode Cs supplying the voltage to the auxiliary capacity Cst after writing the non-video signals, before writing of the video signals and after writing of the video signals and configured so as to superpose the potential of the same polarity as the non-video signals or the video signals on one potential of the pair of the electrodes PE, CE. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device and a driving method of the liquid crystal display device, and more particularly to an active matrix liquid crystal display device and a driving method thereof.

  In general, a liquid crystal display device includes a liquid crystal display panel including an array substrate, a counter substrate disposed to face the array substrate, and a liquid crystal layer sandwiched between the array substrate and the counter substrate.

  In recent years, it is essential to reduce power consumption particularly in liquid crystal display devices used for portable terminals and small game machines that operate on batteries. As a driving method suitable for reducing power consumption in this way, capacitively-coupled driving (CC driving) has been proposed (see, for example, Patent Document 1).

  In a liquid crystal display device that performs capacitive coupling driving, for example, an auxiliary capacitance electrode that extends substantially in parallel with the scan electrode is provided, an auxiliary capacitance is formed between the auxiliary capacitance electrode and the pixel electrode, and the potential of the auxiliary capacitance electrode is set to the level of the scan electrode. The voltage is varied in synchronization with the potential, and a superimposed voltage is applied to the pixel electrode potential by capacitive coupling through the auxiliary capacitance.

  By superimposing the voltage by the auxiliary capacitor, effects such as lowering of the source voltage, reduction of driving power, improvement of response speed, and improvement of driving reliability can be obtained. That is, by using the auxiliary capacitance, it is possible to apply a voltage having a larger amplitude to the pixel electrode while applying a voltage having a small amplitude to the video signal electrode.

  For example, by using a video signal IC with an output voltage width of 5 volts, the voltage width applied to the liquid crystal can be expanded to 10 volts or 15 volts, and the liquid crystal is driven with a voltage higher than the withstand voltage while using a low withstand voltage IC. Is possible. Since the IC can be driven with such a low voltage, circuit power consumption can be reduced.

  In recent years, OCB (Optically Compensated Bend) liquid crystal has attracted attention as a liquid crystal mode having high speed and wide viewing angle characteristics, and its application to liquid crystal TVs, in-vehicle displays, portable terminals, game machines, etc. is being studied. .

In OCB, in order to prevent the so-called reverse transition in which the liquid crystal alignment state returns from the bend state to the splay state, it is necessary to perform black display at a certain time ratio during one frame period. Scanning (hereinafter referred to as black insertion scanning) and at least one scanning for writing video signals (hereinafter referred to as video signal scanning) must be performed (for example, see Patent Document 2).
Japanese Patent Laid-Open No. 5-143021 JP 2007-140066 A

  When the above-described capacitive coupling driving or capacitive coupling dot inversion driving (CCDI driving) is applied to the OCB mode liquid crystal display device, it is necessary to consider not only signal writing scanning but also black insertion scanning.

  For example, when one horizontal period (1H period) is divided into the first half and the second half, and black insertion writing is sequentially performed in the first half and video signal writing is sequentially performed in the second half, generally black signal writing and subsequent video signal writing are Since they have the same polarity, it is necessary to change the storage capacitor electrode potential immediately before video signal writing.

  For example, in black signal writing and subsequent video signal writing, when a positive signal is written to the pixel, it is necessary to apply a positive superimposed voltage from the auxiliary capacitance electrode immediately before black signal writing and video signal writing. is there.

  Therefore, it is necessary to change the corresponding auxiliary capacitance electrode potential to the positive side immediately after writing the black signal, and to change the corresponding auxiliary capacitance electrode potential to the positive side immediately after writing the video signal. In order to perform these operations continuously, it is necessary to temporarily return the auxiliary capacitor electrode potential corresponding to immediately before the video signal writing to the negative electrode side.

  However, when the liquid crystal display device is required to operate at high speed and the time constant of the auxiliary capacitance electrode is not negligible compared to, for example, one horizontal period (1 H time), the driving is performed as described above. As a result, the time constant of the storage capacitor electrode potential is large, and the potential may not converge within one horizontal period.

  In this case, the auxiliary capacitor electrode potential cannot be shifted to the positive electrode side when the scanning line is selected, and a desired superimposed voltage cannot be applied to the pixel electrode. In this case, for example, even when a video signal corresponding to black display is written, the liquid crystal cannot be displayed black due to insufficient holding voltage after voltage superposition, and the contrast may be lowered.

  In addition, when the storage capacitor of the display pixel arranged in the direction in which the scanning line extends is connected to a different storage capacitor electrode, the time constant of the storage capacitor electrode is large, and the potential cannot be converged within one horizontal period, In some cases, the auxiliary capacitor electrode potential arrival level at the time of scanning line selection is different between adjacent display pixels, and the voltage at the time of holding the potential is also different, resulting in vertical streaks.

  Also, in the method in which the potential is sufficiently converged by changing the storage capacitor electrode potential in advance rather than immediately before the video signal writing, the pixel potential fluctuates due to the voltage superposition effect when the storage capacitor electrode potential is changed. If the time from the electrode potential change to the gate selection (video signal writing) is too long, the liquid crystal responds transiently within this period, and the desired display state cannot be obtained, which also causes problems such as a decrease in contrast. There was a case.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device having good display quality and a driving method of the liquid crystal display device, avoiding the occurrence of contrast reduction and vertical stripes. And

  A liquid crystal display device according to a first aspect of the present invention includes a display panel having a display unit in which a plurality of display pixels each having a liquid crystal layer sandwiched between a pair of electrodes are arranged in a matrix, and the liquid crystal display panel. The illumination means for illuminating and writing of the non-video signal in the first period within one frame period, writing of the video signal in the second period following the first period, and in the third period following the second period And a control means for controlling the display means and the illumination means so as to turn on the illumination means, wherein each of the plurality of display pixels has a liquid crystal capacitance generated by a voltage applied to the pair of electrodes. And an auxiliary capacitor coupled to the liquid crystal capacitor, and the control means sets the potential of the auxiliary capacitor electrode for supplying a voltage to the auxiliary capacitor after writing the non-video signal. Auxiliary capacitor electrode potential configured to change before writing a signal and after writing the video signal, and to superimpose a potential of the same polarity as the non-video signal or the video signal on one potential of the pair of electrodes Supply means are provided.

  The driving method of the liquid crystal display device according to the second aspect of the present invention includes a non-video signal writing step for writing a non-video signal to a display pixel in a first period within one frame period, and the first within the one frame period. A video signal writing step of writing a video signal to the display pixel in a second period following the period, and a step of lighting the illumination means in a third period following the second period in the one frame period. A method for driving a liquid crystal display device, the method comprising: changing a potential of an auxiliary capacitor electrode that supplies a voltage to the auxiliary capacitor from a first potential to a second potential after writing the non-video signal; A step of changing the potential of the auxiliary capacitance electrode from a second potential to a first potential immediately before writing; and after writing of the video signal, the potential of the auxiliary capacitance electrode is changed to the first potential. Comprising a step of changing the potential to the second potential.

  According to the present invention, it is possible to provide a liquid crystal display device having a good display quality and a driving method of the liquid crystal display device by avoiding occurrence of contrast reduction and vertical stripes.

  Hereinafter, a liquid crystal display device according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the liquid crystal display device according to the present embodiment includes an OCB mode liquid crystal display panel DP, a backlight BL that illuminates the liquid crystal display panel DP, and a controller that controls the liquid crystal display panel DP and the backlight BL. CNTs are provided.

  The liquid crystal display panel DP has a pair of substrates, that is, the array substrate 1 and the counter substrate 2, and the liquid crystal layer 3 sandwiched between the array substrate 1 and the counter substrate 2. The liquid crystal layer 3 includes, as a liquid crystal material, an OCB mode liquid crystal that is previously transitioned from a splay alignment to a bend alignment, for example, for a normally white display operation. In the present embodiment, the reverse transition from the bend alignment of the liquid crystal to the splay alignment periodically causes the liquid crystal layer 3 to apply a driving voltage (hereinafter referred to as black insertion voltage) corresponding to black display as a high voltage, for example, a non-video signal. It is blocked by applying.

  In addition, the liquid crystal display panel DP includes a display unit DYP including display pixels PX arranged in a substantially matrix shape. The array substrate 1 has a transparent insulating substrate (not shown) such as glass. On the transparent insulating substrate, as shown in FIG. 2, a plurality of pixel electrodes PE corresponding to each display pixel PX are arranged.

  The counter substrate 2 is, for example, a color filter (not shown) composed of red, green, and blue colored layers disposed on a transparent insulating substrate such as glass, and a color filter facing the plurality of pixel electrodes PE. The counter electrode CE and the like are disposed.

  Each pixel electrode PE and counter electrode CE are made of a transparent electrode material such as ITO, for example, and covered with an alignment film (not shown) that is rubbed in a direction parallel to each other. Each pixel electrode PE and counter electrode CE constitute a display pixel PX together with a pixel region which is a part of the liquid crystal layer 3 controlled by the liquid crystal molecular arrangement corresponding to the electric field from the pixel electrode PE and counter electrode CE.

  Further, as shown in FIG. 2, in the display unit DYP, the array substrate 1 includes a plurality of scanning lines G (G1, G2, G3,...) Arranged along a row in which a plurality of pixel electrodes PE are arranged, and a plurality of scanning lines G. A plurality of signal lines S (S1, S2, G3,...) Arranged along a column in which the pixel electrodes PE are arranged, and a plurality of pixels arranged in the vicinity of the intersection positions of the scanning lines G and the signal lines S A switch W is provided.

  Each pixel switch W is composed of, for example, a thin film transistor (TFT). The gate of the pixel switch W is connected to the scanning line G, and the source-drain path is connected between the signal line S and the pixel electrode PE. Each pixel switch W is electrically connected between the corresponding signal line S and the corresponding pixel electrode PE when driven through the corresponding scanning line G.

  Each of the plurality of display pixels PX has a liquid crystal capacitance Clc constituted by the liquid crystal layer 3 held between the pixel electrode PE and the counter electrode CE. The liquid crystal capacitance Clc is determined by the relative dielectric constant of the liquid crystal material, the pixel electrode area, and the liquid crystal cell gap.

  In addition, a part of the pixel electrode PE and a part of the pixel electrode PE and an insulating film are stacked, and the auxiliary capacitance electrodes Cs (Cs1, Cs2, Cs3, ...) constitutes an auxiliary capacitor Cst. In the liquid crystal display device according to the present embodiment, as shown in FIG. 2, the auxiliary capacitors Cst of the display pixels PXA and PXB arranged in a direction substantially parallel to the scanning line G are connected to different auxiliary capacitor electrodes Cs.

  The controller CNT includes a gate driver GD connected to the scanning line G and the shared electrode C, a source driver SD connected to the signal line S, a backlight driver LD that drives the backlight BL, and a gate driver GD and a source driver SD. And a control circuit 5 for controlling the backlight driver (inverter) LD.

  The control circuit 5 is configured to perform an initialization process for changing the liquid crystal molecules from the splay alignment to the bend alignment by changing the counter potential VCom and applying a relatively large driving voltage to the liquid crystal layer 3 when the power is turned on. Yes.

  The control circuit 5 outputs a control signal CTG generated based on the synchronization signal input from the external signal source SS to the gate driver GD, and generates a control signal based on the synchronization signal input from the external signal source SS. The video signal input from the CTS and the external signal source SS or the reverse transition prevention signal for black insertion is output to the source driver SD. Further, the control circuit 5 outputs a counter potential Vcom applied to the counter electrode CE to the counter electrode CE of the counter substrate 2.

  Based on the control signal CTG, the gate driver GD sequentially drives the plurality of scanning lines G so as to conduct the plurality of pixel switches W in units of rows, and supplies the auxiliary capacitor electrode potential to the auxiliary capacitor electrode Cs. In the liquid crystal display device according to the present embodiment, the gate driver GD includes an auxiliary capacitance electrode scanning unit (not shown) that sequentially scans the auxiliary capacitance electrode Cs, and two auxiliary capacitance electrodes are included in the auxiliary capacitance electrode Cs. The potentials VC (a) and VC (b) can be selectively supplied.

  Based on the control signal CTS, the source driver SD outputs a video signal or a non-video signal to the plurality of signal lines S1 to Sn in a period in which the pixel switches W of each row are turned on by driving the corresponding scanning line G. In the liquid crystal display measure according to the present embodiment, one horizontal period (1H period) is divided into the first half and the second half, and the source driver SD outputs a black insertion voltage as a non-video signal in the first half of the one horizontal period. Video signal is output in the second half of the period.

  The non-video signal or the video signal applied to the signal lines S1 to Sn by the source driver SD is applied to the pixel electrode PE of the display pixel PX in the selected row via the corresponding pixel switch W. A potential difference between the voltage signal applied to the pixel electrode PE and the counter potential Vcom applied to the counter electrode CE is held as the liquid crystal capacitance Clc.

  In the liquid crystal display device according to the present embodiment, the gate driver GD is controlled by the control circuit 5, and after the non-video signal is written to the pixel electrode PE of the display pixel PX in the selected row, the video signal is written. Immediately before and after the video signal is written, the potential of the corresponding auxiliary capacitance electrode Cs is changed. As described above, by changing the potential of the corresponding auxiliary capacitance electrode Cs, a non-video signal or a potential having the same polarity as that of the video signal is superimposed on the pixel electrode PE.

  Next, a driving method of the liquid crystal display device according to the present embodiment will be described. As shown in FIGS. 2 and 3, the liquid crystal display device according to the present embodiment employs a dot inversion driving method in which the polarity is inverted for each frame and the polarity is different between pixels. That is, video signals and non-video signals having different polarities are written in the display pixels PXA and PXB adjacent to each other. Further, the polarity of the video signal and the non-video signal written to the display pixel PX is inverted every frame period. Here, the 1H / 1V inversion driving method in which the polarity is inverted between adjacent pixels is taken as an example, but the polarity may be inverted every plural pixels.

  In the liquid crystal display device according to the present embodiment, the control circuit 5 divides one frame period into three periods, the first period is a black insertion period, the second period is a video signal writing period, and the third period is a holding period. . That is, the control circuit 5 controls the gate driver GD, the source driver SD, and the backlight driving unit LD, resets the display state by performing black insertion scanning from the upper end to the lower end of the screen in the first period, and the second period, for example. Then, for example, video signal scanning is performed from the upper end to the lower end of the screen, and the video signal held by turning on the backlight BL in the third period is displayed on the display unit DYP as an image.

  Therefore, as shown in FIG. 3, the control circuit 5 causes the gate driver GD to sequentially drive the scanning lines G in the first period and outputs the black insertion voltage from the source driver SD, and sequentially causes the gate driver GD to sequentially output in the second period. The scanning line G is driven and a video signal is output from the source driver SD.

  Here, for example, if the display pixel PXA and the display pixel PXB are selected by the scanning line G2, a negative black insertion voltage is written to the display pixel PXA in the first period of the odd frame, and the second pixel of the odd frame. A negative video signal is written in a period. Further, a positive black insertion voltage is written in the first period of the even frame, and a positive video signal is written in the second period of the even frame.

  In the display pixel PXB, a positive black insertion voltage is written in the first period of the odd frame, and a positive video signal is written in the second period of the odd frame. Further, a negative black insertion voltage is written in the first period of the even frame, and a negative video signal is written in the second period of the even frame.

  Therefore, the control circuit 5 needs to drive the auxiliary capacitance electrode Cs1 so that the superimposed voltage superimposed by the auxiliary capacitance Cst of the display pixel PXA has a negative polarity in the odd-numbered frame and a positive polarity in the even-numbered frame.

  Further, the control circuit 5 needs to drive the auxiliary capacitance electrode Cs2 so that the superimposed voltage superimposed by the auxiliary capacitance Cst of the display pixel PXB has a positive polarity in the odd frame and a negative polarity in the even frame.

  In the liquid crystal display device driving method according to the present embodiment, as shown in FIG. 3, the voltage VG2 applied to the scanning line G2 is turned on in the first period of the odd-numbered frame, and the display selected by the scanning line G2 is displayed. After the writing of the negative black insertion voltage to the pixel PXA is completed, the value of the auxiliary capacitance electrode potential VC2 applied to the auxiliary capacitance electrode Cs2 is changed from the potential VC (b) to the potential VC (a) (VC (b)> VC (A)). Then, a negative superimposed voltage proportional to the potential difference (| VC (a) −VC (b) |) of the auxiliary capacitance electrode Cs is superimposed on the pixel potential Vd.

  Subsequently, the control circuit 5 holds the value of the auxiliary capacitance electrode potential VC2 of the auxiliary capacitance electrode Cs2 at the potential VC (a) for a certain period, and immediately before the video signal is written to the display pixel PXA, the auxiliary capacitance electrode potential VC2 is stored. Is changed from the potential VC (a) to the potential VC (b). That is, as shown in FIG. 3, the control circuit 5 changes the auxiliary capacitance electrode potential VC2 from the potential VC (a) to the potential VC (b) immediately before the voltage VG2 applied to the scanning line G2 becomes the on level. .

  Subsequently, in the second period of the odd frame, the voltage VG2 applied to the scanning line G2 is turned on, and after the writing of the negative video signal to the display pixel PXA selected by the scanning line G2, the auxiliary capacitance is completed. The value of the auxiliary capacitance electrode potential VC2 applied to the electrode Cs2 is changed from the potential VC (b) to the potential VC (a). Then, a negative superimposed voltage proportional to the potential difference (| VC (b) −VC (a) |) of the auxiliary capacitance electrode Cs is superimposed on the pixel potential Vd.

  In the first period of the even frame, the voltage VG2 applied to the scanning line G2 is turned on, and after the writing of the positive black insertion voltage to the display pixel PXA selected by the scanning line G2 is completed, the auxiliary capacitance The value of the auxiliary capacitance electrode potential VC2 applied to the electrode Cs2 is changed from the potential VC (a) to the potential VC (b). Then, a positive superimposed voltage proportional to the potential difference (| VC (a) −VC (b) |) of the auxiliary capacitance electrode Cs is superimposed on the pixel potential Vd.

  Subsequently, the control circuit 5 holds the value of the auxiliary capacitance electrode potential VC2 of the auxiliary capacitance electrode Cs2 at the potential VC (b) for a certain period, and immediately before the video signal is written to the display pixel PXA, the auxiliary capacitance electrode potential VC2 is stored. Is changed from the potential VC (b) to the potential VC (a). That is, the control circuit 5 changes the auxiliary capacitance electrode potential VC2 from the potential VC (b) to the potential VC (a) immediately before the voltage VG2 applied to the scanning line G2 becomes the on level.

  Subsequently, in the second period of the even frame, the voltage VG2 applied to the scanning line G2 is turned on, and after the writing of the positive video signal to the display pixel PXA selected by the scanning line G2, the auxiliary capacitance is completed. The value of the auxiliary capacitance electrode potential VC2 applied to the electrode Cs2 is changed from the potential VC (a) to the potential VC (b). Then, a positive superimposed voltage proportional to the potential difference (| VC (a) −VC (b) |) of the auxiliary capacitance electrode Cs is superimposed on the pixel potential Vd.

  Further, as shown in FIG. 3, in the first period of the odd frame, the voltage VG2 applied to the scanning line G2 becomes the on level, and writing of the positive black insertion voltage to the display pixel PXB selected by the scanning line G2 is performed. Is completed, the value of the auxiliary capacitance electrode potential VC3 applied to the auxiliary capacitance electrode Cs3 is changed from the potential VC (a) to the potential VC (b). Then, a positive superimposed voltage proportional to the potential difference (| VC (a) −VC (b) |) of the auxiliary capacitance electrode Cs is superimposed on the pixel potential Vd.

  Subsequently, the control circuit 5 holds the value of the auxiliary capacitance electrode potential VC3 of the auxiliary capacitance electrode Cs3 at the potential VC (b) for a certain period, and immediately before the video signal is written to the display pixel PXB, the auxiliary capacitance electrode potential VC3. Is changed from the potential VC (b) to the potential VC (a). That is, as shown in FIG. 3, the control circuit 5 changes the auxiliary capacitance electrode potential VC3 from the potential VC (b) to the potential VC (a) immediately before the voltage VG2 applied to the scanning line G2 becomes the on level. Let

  In the second period of the odd-numbered frame, the voltage VG2 applied to the scanning line G2 becomes the on level, and after the writing of the positive video signal to the display pixel PXB selected by the scanning line G2, is completed, the auxiliary capacitance electrode Cs3 is applied. The value of the applied auxiliary capacitance electrode potential VC3 is changed from the potential VC (a) to the potential VC (b). Then, a positive superimposed voltage proportional to the potential difference (| VC (a) −VC (b) |) of the auxiliary capacitance electrode Cs is superimposed on the pixel potential Vd.

  In the first period of the even frame, the voltage VG2 applied to the scanning line G2 is turned on, and after the writing of the negative black insertion voltage to the display pixel PXB selected by the scanning line G2 is completed, the auxiliary capacitance The value of the auxiliary capacitance electrode potential VC3 applied to the electrode Cs3 is changed from the potential VC (b) to the potential VC (a). Then, a negative superimposed voltage proportional to the potential difference (| VC (b) −VC (a) |) of the auxiliary capacitance electrode Cs is superimposed on the pixel potential Vd.

  Subsequently, the control circuit 5 holds the value of the auxiliary capacitance electrode potential VC3 of the auxiliary capacitance electrode Cs3 at the potential VC (a) for a certain period, and immediately before the video signal is written to the display pixel PXB, the auxiliary capacitance electrode potential VC3. Is changed from the potential VC (a) to the potential VC (b). That is, the control circuit 5 changes the auxiliary capacitance electrode potential VC3 from the potential VC (a) to the potential VC (b) immediately before the voltage VG2 applied to the scanning line G2 becomes the on level.

  Subsequently, in the second period of the even frame, the voltage VG2 applied to the scanning line G2 is turned on, and after the writing of the negative video signal to the display pixel PXB selected by the scanning line G2, the auxiliary capacitance is completed. The value of the auxiliary capacitance electrode potential VC3 applied to the electrode Cs3 is changed from the potential VC (a) to the potential VC (b). Then, a negative superimposed voltage proportional to the potential difference (| VC (b) −VC (a) |) of the auxiliary capacitance electrode Cs is superimposed on the pixel potential Vd.

  By driving the auxiliary capacitance electrodes Cs2 and Cs3 as described above, a superimposed voltage having the same polarity as the video signal and the non-video signal written to the display pixels PXA and PXB selected by the scanning line G2 can be applied.

  As described above, in the driving method of the liquid crystal display device according to the present embodiment, the potential of the auxiliary capacitance electrode Cs is changed between the first period and the second period in which the backlight BL is turned off within one frame period. I am letting. That is, the backlight BL is turned on after the video signal write scan is completed, and even if the potential held in the display pixels PXA and PXB is not in a desired state during the video signal write period. In the meantime, since the backlight BL is turned off, the display quality does not deteriorate.

  That is, according to the liquid crystal display device and the driving method of the liquid crystal display device according to the present embodiment, a liquid crystal display device having a good display quality and a driving method of the liquid crystal display device are provided by avoiding a decrease in contrast and vertical stripes. be able to. Note that the driving method of the liquid crystal display device according to the present embodiment employs CCDI driving, but CC driving can also be employed.

  Next, a liquid crystal display device according to a second embodiment of the present invention and a driving method of the liquid crystal display device will be described below with reference to the drawings. In the liquid crystal display device according to the present embodiment, as shown in FIG. 4, the potential of the auxiliary capacitance electrode Cs is collectively changed. Therefore, unlike the liquid crystal display device according to the first embodiment, the liquid crystal display device according to the present embodiment does not require an auxiliary capacitance electrode scanning unit that scans the auxiliary capacitance electrode Cs. The liquid crystal display device according to the present embodiment is the same as the liquid crystal display device according to the first embodiment described above except for the above points.

  In the driving method of the liquid crystal display device according to the present embodiment, as shown in FIG. 4, the black insertion voltage is written almost simultaneously on the entire screen in the first period of one frame period. In the case shown in FIG. 4, first, the black insertion voltage is simultaneously written to the display pixels PX selected by the odd-numbered scanning lines G1, G3, G5..., And then the even-numbered scanning lines G2, G4, G6. The black insertion voltage is simultaneously written into the selected display pixel PX.

  That is, the control circuit 5 causes the gate driver GD to select the odd-numbered scanning lines G1, G3, G5... And outputs a positive black insertion voltage from the source driver SD to the signal line S (+) at this time. The negative black insertion voltage signal is output to the signal line S (−).

  Therefore, a positive black insertion voltage is written to the display pixels PX selected by the scanning lines G1, G3, G5... Of the columns of the display pixels PXA, and the scanning lines G1, G3, G5. A negative black insertion voltage is written into the selected display pixel PX.

  At this time, the potential of the auxiliary capacitance electrode Cs is the same as that at the time of writing to the display pixel PX selected by the scanning lines G1, G3, G5.

  Next, the control circuit 5 causes the gate driver GD to select the even-numbered scanning lines G2, G4, G6..., And outputs a negative black insertion voltage from the source driver SD to the signal line S (+) at this time. A positive black insertion voltage is output to the signal line S (−).

  Therefore, a negative black insertion voltage is written to the display pixels PX selected by the scanning lines G2, G4, G6... Of the column of the display pixels PXA, and the scanning lines G2, G4, G6. A positive black insertion voltage is written in the selected display pixel PX.

  In the driving method of the liquid crystal display device according to the present embodiment, as described above, after the writing of the black insertion voltage is completed, the control circuit 5 controls the gate driver GD to set the auxiliary capacitance electrodes Cs1, Cs3, Cs5. The auxiliary capacitance electrode potentials VC1, VC3, VC5... Are changed from the potential VC (a) to the potential VC (b), and the auxiliary capacitance electrodes Cs2, Cs4, Cs6. , VC4, VC6... Are changed from the potential VC (b) to the potential VC (a).

  By changing the potential applied to the auxiliary capacitance electrode Cs as described above, a superimposed voltage having the same polarity as the polarity of the black insertion voltage previously performed can be applied to the liquid crystal capacitance Clc of the display pixel PX. it can.

  Subsequently, the control circuit 5 holds the value of the auxiliary capacitance electrode potential VC of each auxiliary capacitance electrode Cs for a certain period, and immediately before the scanning lines G are sequentially driven, the auxiliary capacitance electrodes Cs1, Cs3, Cs5,. The auxiliary capacitance electrode potentials VC1, VC3, VC5... Are changed from the potential VC (b) to the potential VC (a) by collectively driving. That is, the control circuit 5 changes the auxiliary capacitance electrode potentials VC1, VC3, VC5... From the potential VC (b) to the potential VC (a) immediately before the voltage VG applied to the scanning line G is turned on as shown in FIG. ) To all at once.

  Further, immediately before the scanning lines G are sequentially driven, the auxiliary capacitance electrodes Cs2, Cs4, Cs6,... Are collectively driven, and the auxiliary capacitance electrode potentials VC2, VC4, VC6, are changed from the potential VC (a) to the potential VC (b). And change. That is, the control circuit 5 collects the storage capacitor electrode potentials VC2, VC4, VC6,... From the potential VC (b) to the potential VC (a) at the same time immediately before the voltage VG applied to the scanning line G becomes the on level. Change.

  In the subsequent second period of the odd frame, the gate driver GD and the source driver SD are controlled so that the video signal is written to the display pixel PX, similarly to the driving method of the liquid crystal display device according to the first embodiment.

  In the second period, after the video signal is written to the display pixel PX, the control circuit 5 collectively drives the auxiliary capacitance electrodes Cs1, Cs3, Cs5... And sets the auxiliary capacitance electrode potentials VC1, VC3, VC5. The voltage is changed from (a) to the potential VC (b). Further, the auxiliary capacitance electrodes Cs2, Cs4, Cs6,... Are collectively driven to change the auxiliary capacitance electrode potentials VC2, VC4, VC6,... From the potential VC (b) to the potential VC (a).

  The control circuit 5 controls the backlight driver LD so that the backlight BL is turned on after the storage capacitor electrode potential is changed as described above, that is, in the third period of the odd-numbered frame.

  In the first period of the even frame following the odd frame, the black insertion voltage whose polarity is reversed from that of the odd frame is written in the display pixel PX. Therefore, after the black insertion voltage is written in the display pixel PX, the control circuit 5 controls the gate driver GD to drive the auxiliary capacitance electrodes Cs1, Cs3, Cs5. .. Are changed from the potential VC (b) to the potential VC (a), and the auxiliary capacitance electrodes Cs2, Cs4, Cs6,... Are collectively driven to change the auxiliary capacitance electrode potentials VC2, VC4, VC6. ) To potential VC (b).

  Subsequently, the control circuit 5 holds the value of the auxiliary capacitance electrode potential VC of each auxiliary capacitance electrode Cs for a certain period, and immediately before the scanning lines G are sequentially driven, the auxiliary capacitance electrodes Cs1, Cs3, Cs5,. The collective drive is performed to change the auxiliary capacitor electrode potentials VC1, VC3, VC5... From the potential VC (a) to the potential VC (b). That is, the control circuit 5 collects the auxiliary capacitor electrode potentials VC1, VC3, VC5... From the potential VC (a) to the potential VC (b) at once before the voltage VG applied to the scanning line G becomes the on level. Change.

  Further, immediately before the scanning lines G are sequentially driven, the auxiliary capacitance electrodes Cs2, Cs4, Cs6,... Are collectively driven, and the auxiliary capacitance electrode potentials VC2, VC4, VC6, are changed from the potential VC (b) to the potential VC (a). And change. That is, the control circuit 5 collects the storage capacitor electrode potentials VC2, VC4, VC6,... From the potential VC (b) to the potential VC (a) at the same time immediately before the voltage VG applied to the scanning line G becomes the on level. Change.

  In the second period of the even frame, the gate driver GD and the source driver SD are controlled so that the video signal is written to the display pixel PX, similarly to the driving method of the liquid crystal display device according to the first embodiment. .

  In the second period, after the video signal is written to the display pixel PX, the control circuit 5 collectively drives the auxiliary capacitance electrodes Cs1, Cs3, Cs5... And sets the auxiliary capacitance electrode potentials VC1, VC3, VC5. The voltage is changed from b) to the potential VC (a). Further, the auxiliary capacitance electrodes Cs2, Cs4, Cs6,... Are collectively driven to change the auxiliary capacitance electrode potentials VC2, VC4, VC6,... From the potential VC (a) to the potential VC (b).

  The control circuit 5 controls the backlight driver LD so that the backlight BL is turned on after the storage capacitor electrode potential is changed as described above, that is, in the third period of the even frame.

  By driving the auxiliary capacitance electrode Cs as described above, it is not necessary to scan the auxiliary capacitance electrode Cs when controlling the potential of the auxiliary capacitance electrode Cs. That is, in the driving method of the liquid crystal display device according to the present embodiment, since the potential control of the auxiliary capacitance electrode Cs is performed all over the screen, a scanning circuit for the auxiliary capacitance electrode Cs becomes unnecessary.

  For example, in the liquid crystal display device according to the present embodiment, only two power sources (for positive polarity and for negative polarity) for controlling the auxiliary capacitance electrode Cs are prepared to control application of the superimposed voltage on the entire screen. It is possible.

  This reduces the size of the control circuit, thereby reducing the size of the control circuit by reducing the chip area, reducing costs, reducing power consumption, etc., and reducing the cost of the auxiliary capacitance electrode scanning driver and arranging the auxiliary capacitance electrode scanning driver. Therefore, it is possible to reduce the frame area.

  Note that, as in the driving method of the liquid crystal display device according to the present embodiment, when the application of the superimposed voltage from the auxiliary capacitance electrode Cs after writing the video signal is performed all over the screen after the entire screen is scanned, In the initial part of the writing scan (for example, when scanning from the top to the bottom of the screen), the time from when the video signal is written to when the superimposed voltage is applied becomes longer, and the pixel holding potential becomes a halfway value during that time. Therefore, since the liquid crystal responds transiently to the holding potential, there may be a concern that a desired display state cannot be obtained.

  However, in the driving method described above, the lighting of the backlight BL is started after the video signal writing scan is completed, that is, substantially the same timing as the timing of changing the potential of the auxiliary capacitance electrode Cs.

  Therefore, even if the potential held in the display pixel PX is not in a desired state during the video signal writing period, the display quality does not deteriorate because the backlight BL is turned off during that period.

  That is, according to the liquid crystal display device and the driving method of the liquid crystal display device according to the present embodiment, the same effects as the liquid crystal display device and the liquid crystal display device according to the first embodiment described above can be obtained. Further, as in the liquid crystal display device driving method according to the present embodiment, one frame period is divided into three periods, the first period is the black insertion voltage writing period, the second period is the video signal writing period, and the third period is By combining the driving method for the holding period and the CCDI driving method, the driving is performed to apply a superimposed voltage to the display pixel PX via the auxiliary capacitance electrode Cs, and the scanning circuit for the auxiliary capacitance electrode Cs is unnecessary. It can be realized.

  Next, a liquid crystal display device according to a third embodiment of the present invention and a driving method of the liquid crystal display device will be described below with reference to the drawings. As shown in FIG. 5, in the liquid crystal display device according to the present embodiment, in the display unit DYP, the auxiliary capacitance electrode Cs is disposed so as to extend substantially in parallel with the direction in which the signal line S extends. A column inversion driving method is employed in which the polarity is inverted and the polarity is inverted for each column in which the display pixels PX are arranged. Here, a one-column inversion driving method in which polarity is inverted between adjacent columns is taken as an example, but polarity inversion may be performed for each of a plurality of columns.

  In the liquid crystal display device according to the present embodiment, the source driver SD may include an auxiliary capacitance electrode driver, or the auxiliary capacitance electrode driver may be provided independently. When the source driver SD includes an auxiliary capacitance electrode driver, the control signal CTS supplied from the control circuit 5 to the source driver SD includes the auxiliary capacitance electrode control signal.

  Also in the driving method according to the present embodiment, as in the liquid crystal display device driving method according to the second embodiment described above, the auxiliary capacitance electrode scanning unit that scans the auxiliary capacitance electrode Cs is not necessary. Except for the above points, the liquid crystal display device according to the present embodiment is the same as the liquid crystal display device according to the first embodiment described above.

  In the driving method of the liquid crystal display device according to the present embodiment, as shown in FIG. 6, black insertion voltage writing is performed on the entire screen at once. That is, in the first period of the odd-numbered frame, all the scanning lines G are simultaneously selected, a positive black insertion voltage is written to the display pixels PX in the column of the display pixels PXA, and the display pixels in the column of the display pixels PXB are written. Writes a negative video signal.

  At this time, the potential VC (+) of the auxiliary capacitance electrode Cs (+) connected to the auxiliary capacitance Cst of the display pixel PX in the column of the display pixels PXA is the potential VC (a). The potential VC (−) of the auxiliary capacitance electrode Cs (−) connected to the auxiliary capacitance Cst of the display pixel PX in the column of the display pixels PXB is VC (b).

  Next, after a positive black insertion voltage is written to the display pixels PX in the column of the display pixels PXA and a negative video signal is written to the display pixels in the column of the display pixels PXB, the auxiliary capacitance electrode Cs (+ ) Potential VC (+) from potential VC (a) to potential VC (b), and the potential VC (−) of the auxiliary capacitance electrode Cs (−) is changed from potential VC (b) to potential VC (a). By driving the auxiliary capacitance electrodes Cs (+) and Cs (−) as described above, a superimposed voltage having the same polarity as the supplied black insertion voltage can be applied to each display pixel PX. .

  Subsequently, the control circuit 5 holds the value of the auxiliary capacitance electrode potential VC of each auxiliary capacitance electrode Cs for a certain period, and immediately before the positive video signal is written to the display pixels PX in the column of the display pixels PXA. The potential VC (+) of the auxiliary capacitance electrode Cs (+) is changed from the potential VC (b) to the potential VC (a). That is, the control circuit 5 changes the auxiliary capacitance electrode potential VC (+) from the potential VC (b) to the potential VC (a) immediately before the voltage VG applied to the scanning line G becomes the on level.

  Further, immediately before the negative video signal is written to the display pixel PX in the column of the display pixels PXB, the potential VC (−) of the auxiliary capacitance electrode Cs (−) is changed from the potential VC (a) to the potential VC (b). Change. That is, the control circuit 5 changes the auxiliary capacitance electrode potential VC (−) from the potential VC (a) to the potential VC (b) immediately before the voltage VG applied to the scanning line G becomes the on level.

  Next, in the second period of the odd-numbered frame period, the scanning lines G are sequentially scanned to write video signals to the display pixels PX. Also at this time, the polarity of the video signal supplied to the display pixel PX is the same for each column in which the display pixels PX are arranged (that is, column inversion).

  Then, after a positive video signal is written to the display pixel PX in the column and a negative video signal is written to the display pixel PX in the column of the display pixel PXB, the auxiliary capacitor electrode Cs (+) is supplied to the display pixel PXA. The potential is changed from the potential VC (a) to the potential VC (b). Further, the potential of the auxiliary capacitance electrode Cs (−) is changed from the potential VC (b) to the potential VC (a). By driving the auxiliary capacitance electrodes Cs (+) and Cs (−) as described above, a superimposed voltage having the same polarity as the supplied video signal can be applied to each display pixel PX.

  In the third period of the subsequent odd frame, the control circuit 5 controls the backlight driver LD so as to turn on the backlight BL.

  In the even frame, the polarities of the video signal and the non-video signal supplied to the display pixel PX are inverted, and the same operation as in the odd frame is repeated. That is, in the first period of the even frame, all the scanning lines G are simultaneously selected, a negative black insertion voltage is written to the display pixels PX in the column of the display pixels PXA, and the display pixels in the column of the display pixels PXB are written. Writes a video signal of positive polarity.

  At this time, the potential VC (+) of the auxiliary capacitance electrode Cs (+) connected to the auxiliary capacitance Cst of the display pixel PX in the column of the display pixels PXA is the potential VC (b). The potential VC (−) of the auxiliary capacitance electrode Cs (−) connected to the auxiliary capacitance Cst of the display pixel PX in the column of the display pixels PXB is VC (a).

  Next, after the negative black insertion voltage is written to the display pixels PX in the column of the display pixels PXA and the positive video signal is written to the display pixels in the column of the display pixels PXB, the auxiliary capacitance electrode Cs (+ ) Potential VC (+) is changed from potential VC (b) to potential VC (a), and the potential VC (−) of the auxiliary capacitance electrode Cs (−) is changed from potential VC (a) to potential VC (b). To change. By driving the auxiliary capacitance electrodes Cs (+) and Cs (−) as described above, a superimposed voltage having the same polarity as the supplied black insertion voltage can be applied to each display pixel PX.

  Subsequently, the control circuit 5 holds the value of the auxiliary capacitance electrode potential VC of each auxiliary capacitance electrode Cs for a certain period, and immediately before the negative-polarity video signal is written to the display pixels PX in the column of the display pixels PXA. The potential VC (+) of the auxiliary capacitance electrode Cs (+) is changed from the potential VC (a) to the potential VC (b). That is, the control circuit 5 changes the auxiliary capacitance electrode potential VC (+) from the potential VC (a) to the potential VC (b) immediately before the voltage VG applied to the scanning line G becomes the on level.

  Further, immediately before the positive video signal is written to the display pixels PX in the column of the display pixels PXB, the potential VC (−) of the auxiliary capacitance electrode Cs (−) is changed from the potential VC (b) to the potential VC (a). Change. That is, the control circuit 5 changes the auxiliary capacitance electrode potential VC (−) from the potential VC (b) to the potential VC (a) immediately before the voltage VG applied to the scanning line G becomes the on level.

  Next, in the second period of the even frame, the scanning lines G are sequentially scanned to write video signals to the display pixels PX. Then, after the video signal writing scan is completed, the potential of the auxiliary capacitance electrode Cs (+) is changed from the potential VC (b) to the potential VC (a). Further, by driving the auxiliary capacitance electrodes Cs (+) and Cs (−) as described above for changing the electric potential of the auxiliary capacitance electrode Cs (−) from the electric potential VC (a) to the electric potential VC (b), A superimposed voltage having the same polarity as the supplied video signal can be applied to the display pixel PX.

  That is, according to the liquid crystal display device and the liquid crystal display device according to the present embodiment, the same effects as those of the liquid crystal display device and the liquid crystal display device driving method according to the first embodiment described above can be obtained.

  Also in the driving method according to the present embodiment, as in the liquid crystal display device driving method according to the second embodiment described above, the auxiliary capacitance electrode scanning unit that scans the auxiliary capacitance electrode Cs is not necessary. Therefore, similar to the driving method of the liquid crystal display device according to the second embodiment described above, the reduction in the size of the control circuit realizes miniaturization by reducing the chip area of the control circuit, cost reduction, power consumption reduction, etc. Reduction of the auxiliary capacitor electrode scanning driver cost and reduction of the frame area for arranging the auxiliary capacitance electrode scanning driver can be realized.

  Further, since the liquid crystal display device driving method according to the present embodiment employs column inversion driving as compared with the liquid crystal display device driving method according to the second embodiment described above, the source during the signal writing scanning period is used. The output polarity of the driver SD is constant, and power consumption for signal line charging / discharging due to polarity inversion does not occur. As a result, the liquid crystal display device according to the present embodiment can further reduce power consumption as compared with the liquid crystal display device according to the fourth embodiment described above.

  Note that when the auxiliary capacitance electrode Cs is arranged so as to extend substantially in parallel with the signal line S, for example, the signal line S and the auxiliary capacitance electrode Cs are arranged so as to overlap with each other through an insulating layer. Can be prevented from decreasing.

  At this time, if the auxiliary capacitance electrode Cs and the signal line S have a three-layer structure with an insulating layer interposed therebetween as described above, the parasitic capacitance generated between the signal line S and the Cs line increases, but the column as described above. In the inversion driving method, no electric power is generated due to the charging / discharging of the signal line S, which is not a problem.

  Although the case where column inversion driving is employed has been described here, it is of course possible to employ a configuration in which the polarities of all the columns are the same (that is, frame inversion driving). In the frame inversion driving, since the polarities of all the pixels in the screen are the same, the superimposed voltage from the auxiliary capacitance electrode Cs is the same in all the screens, and the auxiliary capacitance electrode Cs is arranged to extend substantially in parallel with the signal line S. Alternatively, it may be arranged so as to extend substantially parallel to the scanning line G.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In each of the above embodiments, the line inversion driving method, the column inversion driving method, the dot inversion driving method, and the like have been described. However, it is not always necessary to invert the polarity for each row or column. Of course, a configuration in which the polarity is inverted or the polarity is inverted every three columns (this corresponds to, for example, the case where the RGB three colors are set and the polarity is inverted every set) is also possible.

  In the liquid crystal display device and the driving method of the liquid crystal display device according to the second embodiment and the third embodiment described above, the case where the black insertion signal is written to the display pixels at the same time has been described. You can go there. In that case, at least the black insertion scanning is performed at a higher speed than the video signal writing scanning. Even in this case, the same effects as those of the liquid crystal display device and the liquid crystal display device according to the second and third embodiments described above can be obtained.

  Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine the component covering different embodiment suitably.

1 is a diagram schematically illustrating a configuration example of a liquid crystal display device according to an embodiment of the present invention. The figure for demonstrating one structural example of the display part of the liquid crystal display device which concerns on 1st Embodiment of this invention. FIG. 3 is a diagram for explaining an example of a driving method of the liquid crystal display device according to the first embodiment of the present invention. The figure for demonstrating an example of the drive method of the liquid crystal display device which concerns on 2nd Embodiment of this invention. The figure for demonstrating one structural example of the display part of the liquid crystal display device which concerns on 3rd Embodiment of this invention. The figure for demonstrating an example of the drive method of the liquid crystal display device which concerns on 3rd Embodiment of this invention.

Explanation of symbols

  DP ... Liquid crystal display panel, BL ... Back light, CNT ... Controller (control means), PX ... Display pixel, PE ... Pixel electrode, CE ... Counter electrode, Clc ... Liquid crystal capacitance, Cs ... Auxiliary capacitance electrode, Cst ... Auxiliary capacitance, VC: auxiliary capacitance electrode potential, 3 ... liquid crystal layer.

Claims (8)

A display panel having a display unit in which a plurality of display pixels each having a liquid crystal layer sandwiched between a pair of electrodes are arranged in a matrix;
Illumination means for illuminating the liquid crystal display panel;
A non-video signal is written in a first period within one frame period, a video signal is written in a second period following the first period, and the illumination means is turned on in a third period following the second period. And a control means for controlling the display panel and the illumination means, and a liquid crystal display device comprising:
Each of the plurality of display pixels includes a liquid crystal capacitor generated by a voltage applied to the pair of electrodes, and an auxiliary capacitor coupled to the liquid crystal capacitor,
The control means changes the potential of the auxiliary capacitor electrode for supplying a voltage to the auxiliary capacitor after the non-video signal is written, before the video signal is written, and after the video signal is written. A liquid crystal display device comprising auxiliary capacitor electrode potential supply means configured to superimpose the non-video signal or a potential having the same polarity as the video signal on one of the potentials. In the display unit, the plurality of auxiliary capacitance electrodes are arranged so as to extend substantially parallel to the rows or columns in which the display pixels are arranged,
The liquid crystal display device according to claim 1, wherein the control unit further includes an auxiliary capacitance electrode scanning unit that sequentially scans the plurality of auxiliary capacitance electrodes. A plurality of the auxiliary capacitance electrodes are arranged to extend substantially in parallel with the row in which the plurality of display pixels are arranged,
The storage capacitor of the display pixel arranged in the first row is connected to the first storage capacitor electrode,
The storage capacitor of the display pixel arranged in the second row is connected to the second storage capacitor electrode,
The control means reverses polarity of the non-video signal and the video signal supplied between the display pixel arranged in the first row and the display pixel arranged in the second row. Further comprising means,
The auxiliary capacitance electrode potential supply means changes the potential of the first auxiliary capacitance electrode from the first potential to the second potential after the non-video signal is written, and immediately before the video signal is written, from the second potential to the first potential. And changing the potential of the second auxiliary capacitance electrode from the second potential to the first potential after writing the non-video signal, and writing the video signal. 3. A liquid crystal display device according to claim 1, further comprising means for changing from the first potential to the second potential immediately before signal writing and changing from the second potential to the first potential after writing the video signal. A plurality of the auxiliary capacitance electrodes are arranged so as to extend substantially parallel to the row in which the plurality of display pixels are arranged,
The auxiliary capacitance of the first display pixel arranged in the first row is connected to the first auxiliary capacitance electrode,
The auxiliary capacitance of the second display pixel arranged in the first row and adjacent to the first display pixel is connected to the second auxiliary capacitance electrode,
The control means further includes polarity inversion means for inverting the polarity of the non-video signal and the video signal supplied between the first display pixel and the second display pixel,
The auxiliary capacitance electrode potential supply means changes the potential of the first auxiliary capacitance electrode from the first potential to the second potential after writing the non-video signal, and from the second potential to the first potential immediately before writing the video signal. Changing the first potential from the first potential to the second potential after writing the video signal, changing the potential of the second auxiliary capacitance electrode from the second potential to the first potential after writing the non-video signal, 3. The liquid crystal display device according to claim 1, further comprising means for changing from the first potential to the second potential immediately before writing and changing from the second potential to the first potential after writing the video signal. The control means further comprises non-video signal writing means configured to perform writing of the non-video signal for each display pixel arranged in a plurality of rows,
The liquid crystal display device according to claim 1, wherein the storage capacitor electrode potential supply unit includes a unit that collectively changes a plurality of storage capacitor electrode potentials. A plurality of the auxiliary capacitance electrodes are arranged along a column in which the plurality of display pixels are arranged,
The auxiliary capacitance of the display pixel arranged in the first column is connected to the first auxiliary capacitance electrode,
The storage capacitor of the display pixel arranged in the second column is connected to the second storage capacitor electrode,
The control means reverses the polarity of the supplied video signal and the non-video signal between the display pixel arranged in the first column and the display pixel arranged in the second column. The liquid crystal display device according to claim 1, further comprising means.   The liquid crystal display device according to claim 1, wherein the liquid crystal layer includes OCB mode liquid crystal. A non-video signal writing step of writing a non-video signal to a display pixel in a first period within one frame period;
A video signal writing step of writing a video signal to the display pixel in a second period following the first period in the one frame period;
Turning on the illumination means in a third period following the second period within the one frame period, and a driving method of a liquid crystal display device,
After writing the non-video signal, changing the potential of the auxiliary capacitance electrode for supplying a voltage to the auxiliary capacitance from a first potential to a second potential;
Changing the potential of the auxiliary capacitance electrode from the second potential to the first potential immediately before writing the video signal;
And a step of changing the potential of the auxiliary capacitance electrode from the first potential to the second potential after writing the video signal.

Images