JP2006072211A - Liquid crystal display and driving method of liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress degradation in picture quality caused by a parasitic capacitance formed between a signal line and a common line (auxiliary capacitive line) and to reduce electric power consumption in a liquid crystal display having a plurality of liquid crystal display panels having signal lines wired in common. <P>SOLUTION: When line inversion driving is carried out in a liquid crystal display having two liquid crystal display panels, polarities of common voltages V<SB>COM1</SB>, V<SB>COM2</SB>applied on common lines of the respective liquid crystal display panels are simultaneously inverted into opposite polarities to each other by each scanning line. The display signal applied on a signal line is inverted to be opposite to the common voltage of the liquid crystal display panel as a current display object. Further, in one liquid crystal display panel which is not required for higher picture quality, polarities of the display signal and the common voltages V<SB>COM1</SB>, V<SB>COM2</SB>may be inverted by a plurality of scanning lines in the display period of the liquid crystal panel, so that the polarity inversion period may be longer than the polarity inversion period of the other liquid crystal display panel in a display period. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device including a plurality of liquid crystal display panels and a driving method thereof.

  In portable electronic devices such as mobile phones and PDAs, liquid crystal display devices that can be reduced in weight, thickness, and power consumption are often used as display devices. In particular, active matrix liquid crystal display devices using thin film transistors (TFTs) as active elements are widely used.

In such a liquid crystal display device, a plurality of scanning lines and a plurality of signal lines are arranged orthogonally on the liquid crystal display panel, and display pixels are formed in the vicinity of each intersection.
FIG. 8 is an equivalent circuit diagram illustrating an example of the configuration of the display pixel. As shown in the figure, liquid crystal is provided between a pixel electrode 14a connected to the scanning line G and the signal line S via a thin film transistor (TFT) 12, and a counter electrode 14b disposed at a position facing the pixel electrode 14a. Is formed between the pixel electrode 14a and the counter electrode 14b. The auxiliary capacitor 16 is connected in parallel to the pixel capacitor 14 and holds the voltage applied to the pixel capacitor 14. Image display is realized by changing the alignment of the liquid crystal by the electric field.

More specifically, the gate electrode 12 a of the thin film transistor 12 is connected to the scanning line G, the source electrode 12 b is connected to the signal line S, and the drain electrode 12 c is connected to the pixel electrode 14 a of the pixel capacitor 14 and one electrode of the auxiliary capacitor 16. It is connected. A predetermined common voltage (counter electrode signal) _VCOM is applied to the counter electrode 14b, and the other electrode of the auxiliary capacitor 16 is connected to a common line (auxiliary capacitor line) C. When the high potential is applied to the gate electrode 12a via the scanning line G and the thin film transistor 12 is turned on, the potential of the signal line S is applied to the pixel electrode 14a, so that the pixel electrode 14a is connected to the counter electrode 14b. An electric field is formed on the liquid crystal, and the liquid crystal filled between the electrodes is driven.

  In the liquid crystal display device, a backlight such as an LED is provided on the back surface of the liquid crystal display panel, for example, so that the display image can be captured visually. Then, the amount of light emitted from the backlight is controlled by the arrangement of the liquid crystals, and the luminance of each display pixel is adjusted.

In recent years, a liquid crystal display device having a plurality of liquid crystal display panels represented by a foldable mobile phone including a main display and a sub display is also known. In such a liquid crystal display device having a plurality of liquid crystal display panels, signal lines are often shared in order to simplify the structure. For example, in the case of having two liquid crystal display panels, signal lines arranged in one liquid crystal display panel are extended and wired to the other liquid crystal display panel, and both liquid crystal display panels are driven by one source driver circuit. Configured as follows. The scanning line is wired separately for each liquid crystal display panel, and the common voltage V _COM applied to the counter electrode of each liquid crystal display panel is generated for each liquid crystal display panel (for example, Patent Document 1).
JP 2004-163790 A

  In general, in a liquid crystal display device, inversion driving is performed to invert an electric field (polarity) between a pixel electrode and a counter electrode filled with liquid crystal at a predetermined period. In the liquid crystal display panel, as described above, the alignment of the liquid crystal is determined according to the electric field between the electrodes. However, when a direct current is applied between the electrodes, the glass substrate is baked or the liquid crystal is deteriorated or destroyed. Cause it to cause. For this reason, this is prevented by periodically inverting the polarity between the electrodes.

  As an inversion driving method, the polarity of each display pixel is inverted for each scanning line and line inversion is also performed for each frame period, or frame inversion is performed for inverting the polarity of each display pixel for each frame period. It is. Here, the “frame” is a unit of a period during which one image is displayed on each liquid crystal display panel.

FIG. 9 shows an example of a conventional driving waveform when two liquid crystal display panels having a common signal line are driven in an inverted manner. FIG. 4A is a waveform diagram in the case of line inversion driving, and FIG. 4B is a waveform diagram in the case of frame inversion driving. However, the number of scanning lines of one liquid crystal display panel is “m1”, and the number of scanning lines of the other liquid crystal display panel is “m2”. In this figure, with the horizontal axis as the time axis, the scanning timing of the scanning line G (gate scanning), the display signal applied to the signal line S (source output), and the counter electrode of one liquid crystal display panel in order from the top. A common voltage V _COM1 to be applied and a common voltage V _COM2 to be applied to the counter electrode of the other liquid crystal display panel are shown.

As shown in the figure, when two liquid crystal display panels are provided, one frame period includes a first screen display period in which one liquid crystal display panel is a display target and a second screen in which the other liquid crystal display panel is a display target. It consists of a screen display period. In the first screen display period, scanning lines G _{1 to} G _{m1 of one} liquid crystal display panel are sequentially scanned (scanned) to be sequentially selected, and a display signal of an image to be displayed on the liquid crystal display panel is a signal line. Applied to S. In the second screen display period, the scanning lines G _{m1 + 1 to} G _{m1 + m2} of the other liquid crystal display panel are sequentially selected, and the display signal of the image displayed on the liquid crystal display panel is the signal line S. To be applied. That is, a desired image is displayed on each liquid crystal display panel by alternately displaying the two liquid crystal display panels.

In the line inversion, as shown in FIG. 5A, the polarities of the display signal and the common voltages V _COM1 and V _COM2 are inverted for each scanning line and also for each frame period. At this time, the common voltages V _COM1 and V _COM2 are controlled so as to always have the same polarity (so that the polarities match), and the display signal is controlled so that the polarity is opposite to that of the common voltages V _COM1 and V _COM2. The

In the frame inversion, the display signal and the common voltages V _COM1 and V _COM2 are inverted every frame period as shown in FIG. At this time, the common voltages V _COM1 and V _COM2 are controlled so as to always have the same polarity (so that the polarities match), and the display signal is controlled so that the polarity is opposite to that of the common voltages V _COM1 and V _COM2. The That is, the polarity between the pixel electrode and the counter electrode is inverted every frame period.

  By the way, in the matrix type liquid crystal display device, as shown in FIG. 10, the signal line S and the common line (auxiliary capacitance line) C are close to each other, that is, the signal line S and the common line C. It is known that a parasitic capacitance 18 is formed between the two. That is, in the case of a liquid crystal display device having two liquid crystal display panels, when attention is paid to one signal line S, it is formed in the vicinity of the intersection with each common line C of one liquid crystal display panel as shown in FIG. This is equivalent to the parallel connection of the parasitic capacitors 18A,... And the parasitic capacitors 18B formed in the vicinity of the intersections with the respective common lines of the other liquid crystal display panel.

A potential difference between the signal line S and the common line C is applied to both ends of the parasitic capacitance 18, but in the case of inversion driving, the polarity of the signal line S and the common line C is inverted when the polarity is inverted. The polarity at both ends of the capacitor 18 is reversed, and charging / discharging of the parasitic capacitor 18 occurs. That is, every time the polarity is reversed, the polarity at both ends of the parasitic capacitance 18 is reversed and charging / discharging is repeated, and a current (charge / discharge current) resulting from this flows. As a result, as shown in FIG. 12, the display signal on the signal line S, which is ideally a square wave, and the rising and falling waveforms of the common voltages V _COM1 and V _COM2 on the common line C are degraded (blunted). ).

In the liquid crystal display panel, as described above, image display is performed by controlling the arrangement of the liquid crystal by the electric field between the pixel electrode and the counter electrode. However, when the waveform of the display signal and the common voltage _VCOM deteriorates during polarity inversion. As a result, the electric field between the electrodes changes to cause deterioration in the image quality of the display image.

In the conventional inversion drive, as shown in FIG. 9, the inversion control is performed so that the common voltages V _COM1 and V _COM2 of the liquid crystal display panels always coincide. Therefore, when viewed from the signal line S, the polarities of all ends of the parasitic capacitors 18A,..., 18B,... Formed between the signal line S and each common line C are the same. . Therefore, the influence of these parasitic capacitances 18A and 18B is superimposed, and as a result, the degree of waveform deterioration of the display signal and the common voltages V _COM1 and V _COM2 is increased, and compared with an image when each waveform is a square wave. Image quality deterioration was inevitable.

In addition, every time the polarity is inverted, a current (charge / discharge current) due to charging / discharging of the parasitic capacitance 18 flows, so that power consumption occurs. In the conventional inversion driving method described above, the common voltage V of each liquid crystal display panel _{Since COM1} and _VCOM2 are reversed in polarity at the same timing and at the same timing, one liquid crystal display panel having substantially the total number of scanning lines of each liquid crystal display panel is inverted and driven. It was about the same power consumption as when doing. However, this was a wasteful power consumption not related to image display.

  In view of the above circumstances, the present invention is caused by parasitic capacitance formed between a signal line and a common line (auxiliary capacitance line) in a liquid crystal display device including a plurality of liquid crystal display panels in which signal lines are wired in common. The purpose is to reduce image quality degradation and to reduce power consumption.

In order to solve the above-described problem, the invention according to claim 1 is arranged in a matrix in the vicinity of the intersections of the plurality of scanning lines and the plurality of signal lines, and is connected to the pixel electrode and the auxiliary capacitance electrode connected to the pixel electrode. And a plurality of common electrodes that are connected to the counter electrode and connected to the auxiliary capacitance electrode and intersect the plurality of signal lines. In a liquid crystal display device comprising a plurality of liquid crystal display panels having a line,
At least some of the plurality of signal lines of each liquid crystal display panel are wired in common between the liquid crystal display panels,
Counter electrode driving means for applying a counter electrode signal whose polarity is inverted at a predetermined cycle to the common line of each liquid crystal display panel;
Scanning side driving means for sequentially selecting the plurality of scanning lines of each liquid crystal display panel within a frame and sequentially setting the liquid crystal display panels in a display period;
The counter electrode signals applied to the counter electrodes of the liquid crystal display panels have timings that at least simultaneously reverse the polarities to the opposite polarities.

  According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect of the present invention, the timings at which the counter electrode signals are inverted in polarity to each other are always the same.

  According to a third aspect of the present invention, in the liquid crystal display device according to the first aspect, the polarity inversion period of each counter electrode signal is different for each display period in the frame.

  According to a fourth aspect of the present invention, in the liquid crystal display device according to the first aspect, in each of the display periods in a frame, the counter electrode signal among the counter electrode signals is set for the liquid crystal display panel set in the display period. The polarity inversion period of the counter electrode signal is set to be constant.

  According to a fifth aspect of the present invention, in the liquid crystal display device according to the fourth aspect, in each of the display periods, the polarity of the counter electrode signal with respect to the liquid crystal display panel that is not set in the display period among the counter electrode signals. The inversion cycle is set longer than the polarity inversion cycle of the counter electrode signal for the liquid crystal display panel set in the display period.

According to a sixth aspect of the present invention, a plurality of pixels arranged in a matrix in the vicinity of each intersection of a plurality of scanning lines and a plurality of signal lines, and having a pixel electrode and an auxiliary capacitance electrode connected to the pixel electrode, A plurality of liquid crystals having a counter electrode disposed at a position facing each pixel electrode, and a plurality of common lines connected to the counter electrode and connected to the auxiliary capacitance electrode and intersecting the signal lines In a liquid crystal display device comprising a display panel,
At least some of the plurality of signal lines of each liquid crystal display panel are wired in common between the liquid crystal display panels,
Counter electrode driving means for applying a counter electrode signal whose polarity is inverted at a predetermined cycle to the common line of each liquid crystal display panel;
Scanning-side driving means for selecting one liquid crystal display panel of the plurality of liquid crystal display panels for each predetermined plurality of frames, selecting another liquid crystal display panel for each frame, and setting the selected liquid crystal display panel to a display period; ,
It is characterized by providing.

  According to a seventh aspect of the present invention, in the liquid crystal display device according to the sixth aspect of the present invention, the period of the polarity inversion of the counter electrode signal with respect to the one liquid crystal display panel among the counter electrode signals is the predetermined plurality of frames. And the period of polarity inversion of the counter electrode signal with respect to the other liquid crystal display panel is set for each frame.

According to an eighth aspect of the present invention, a plurality of pixels having a pixel electrode and an auxiliary capacitance electrode connected to the pixel electrode, arranged in a matrix in the vicinity of each intersection of the plurality of scanning lines and the plurality of signal lines, A plurality of liquid crystals having a counter electrode disposed at a position facing each pixel electrode, and a plurality of common lines connected to the counter electrode and connected to the auxiliary capacitance electrode and intersecting the signal lines A display panel, wherein at least some of the plurality of signal lines of each liquid crystal display panel are driving methods for driving liquid crystal display devices wired in common between the liquid crystal display panels,
An operation of applying a polarity inversion at a predetermined cycle to the common line of each liquid crystal display panel so that the counter electrode signal has at least a timing of simultaneously reversing the polarities to each other.
In the frame, each liquid crystal display panel is sequentially selected, and each liquid crystal display panel is sequentially set to a display period;
It is characterized by including.

  According to a ninth aspect of the present invention, in the method for driving a liquid crystal display device according to the eighth aspect, the method includes controlling to always simultaneously perform the timing of polarity inversion of the respective counter electrode signals to the opposite polarities. Features.

  According to a tenth aspect of the present invention, in the method for driving a liquid crystal display device according to the eighth aspect, the operation of controlling the polarity inversion period of each counter electrode signal to be different for each display period in the frame. It is characterized by including.

  According to an eleventh aspect of the present invention, in the driving method of the liquid crystal display device according to the eighth aspect, the liquid crystal set in the display period among the counter electrode signals in the display periods in the frame. And an operation of controlling the polarity inversion period of the counter electrode signal with respect to the display panel to be constant.

According to a twelfth aspect of the present invention, a plurality of pixels arranged in a matrix in the vicinity of each intersection of a plurality of scanning lines and a plurality of signal lines, each having a pixel electrode and an auxiliary capacitance electrode connected to the pixel electrode, A plurality of liquid crystals having a counter electrode disposed at a position facing each pixel electrode, and a plurality of common lines connected to the counter electrode and connected to the auxiliary capacitance electrode and intersecting the signal lines A display panel, wherein at least some of the plurality of signal lines of each liquid crystal display panel are driving methods for driving liquid crystal display devices wired in common between the liquid crystal display panels,
An operation of applying a counter electrode signal to the common line of each liquid crystal display panel by reversing the polarity at a predetermined period;
Selecting one liquid crystal display panel of the plurality of liquid crystal display panels for each predetermined plurality of frames, selecting another liquid crystal display panel for each frame, and setting the selected liquid crystal display panel to a display period;
It is characterized by including.

  According to a thirteenth aspect of the present invention, in the driving method of the liquid crystal display device according to the twelfth aspect, the polarity of the counter electrode signal for the one liquid crystal display panel is inverted every predetermined number of frames, and the other liquid crystal display It includes an operation for controlling the polarity of the counter electrode signal for the display panel to be inverted every frame.

  According to the present invention, in a liquid crystal display device including a plurality of liquid crystal display panels with signal lines wired in common, between the signal lines wired in common and the common lines (auxiliary fee lines) of the liquid crystal display panels. Therefore, image quality deterioration and power consumption due to parasitic capacitance formed in the LCD can be suppressed, and image quality can be improved and power consumption can be reduced as compared with a conventional liquid crystal display device.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following, a liquid crystal display device having two liquid crystal display panels sharing a signal line (source line) will be described. In the following, a case where one driver circuit including a source driver circuit and a gate driver circuit is configured to be shared by two liquid crystal display panels will be described, but the present invention is not limited to this. For example, one source driver circuit may be shared by two liquid crystal display panels, and a dedicated gate driver circuit may be provided for each liquid crystal display panel. In addition, the two liquid crystal display panels of the liquid crystal display device described below have the same number of signal lines. However, the present invention is not limited to this, for example, the number of signal lines of one liquid crystal display panel. However, the number of signal lines of the other liquid crystal display panel may be larger than the number of signal lines, and a part of the signal lines of one liquid crystal display panel may not be commonly wired to the other liquid crystal display panel.

[Configuration of liquid crystal display device]
First, the configuration of the liquid crystal display device in this embodiment will be described.

  FIG. 1 is a schematic configuration diagram of a liquid crystal display device 1 according to the present embodiment. As shown in the figure, the liquid crystal display device 1 of the present embodiment has two display screens, and includes a liquid crystal display panel 10A as a first screen and a liquid crystal display panel 10B as a second screen. ing. The liquid crystal display panels 10A and 10B are electrically connected through, for example, a flexible printed circuit board FPC. Further, a driver circuit (driving circuit) 20 including a source driver circuit (signal side driving means), a gate driver circuit (scanning side driving means), and a VCOM circuit (counter electrode driving means), which will be described later, is provided on the liquid crystal display panel 10B side. As a result, both the liquid crystal display panels 10A and 10B are driven.

  FIG. 2 is a block diagram showing the overall configuration of the liquid crystal display device 1. As shown in the figure, the liquid crystal display device 1 includes a liquid crystal display panel 10A, 10B, a source driver circuit 22, gate driver circuits 24A, 24B, VCOM circuits 26A, 26B, an inverted RGB generation circuit 30, and an LCD controller 40. And comprising. The source driver circuit 22, the gate driver circuits 24A and 24B, and the VCOM circuits 26A and 26B are included in the driver circuit 20 of FIG.

FIG. 3 is a circuit configuration diagram showing an equivalent circuit of each liquid crystal display panel. As shown in FIGS. 1 to 3, the liquid crystal display panel 10A, in the row direction, and m1 scanning line connected to the gate driver circuit 24A (gate lines) G ₁ ~G _m1 are arranged (the wiring) together we are, in the column direction, n of signal lines connected to the source driver circuit 22 (source lines) S ₁ to S _n are arranged. To each near an intersection between the scanning line G ₁ ~G _m1 and the signal lines S ₁ to S _n, and thin film transistor 12 is active element, a pixel electrode - pixel capacitance formed by filling liquid crystal between the opposed electrode (liquid crystal A display pixel is formed which includes a capacitor 14 and an auxiliary capacitor 16 which is provided in parallel with the pixel capacitor 14 and holds a signal voltage applied to the pixel capacitor 14. That is, the first screen having the number of pixels “n × m1” is formed on the liquid crystal display panel 10A.

More specifically, the pixel capacitor 14 includes a common line C1 in which a pixel electrode is connected to the scanning line G and the signal line S via the thin film transistor 12, and a counter electrode is connected to a VCOM circuit (counter electrode driving unit) 26A. The common voltage (counter electrode signal) V _COM1 generated by the VCOM circuit 26A is applied via the common line C1.

When the scanning line G ₁ ~G _m1 is been in the selected state is sequentially high voltage, becomes a thin film transistor 12 is ON in each display pixel corresponding signal lines S ₁ to S _n voltage corresponding to respective display pixels Is applied, display data for one line is written, and one image is displayed on the liquid crystal display panel 10A.

Further, the signal lines S ₁ to S _n which are wired in the liquid crystal display panel 10A is extended to the liquid crystal display panel 10B via the flexible printed circuit board EPC (distraction).

In the liquid crystal display panel 10B, m2 scanning lines G _{m1 + 1 to} G _{m1 + m2} connected to the gate driver circuit 24B are arranged in the row direction, and extended from the liquid crystal display panel 10A in the column direction. N signal lines S _{1 to} S _n are arranged. To each near an intersection between the scanning lines G _{m1 +} 1 ~G _m1 + _m2 and the signal lines S ₁ to S _n, similarly to the liquid crystal display panel 10A, a thin film transistor 12, a pixel capacitance 14, and the auxiliary capacitor 16 Are formed. That is, a second screen having the number of pixels “n × m2” is formed on the liquid crystal display panel 10B.

Further, the counter electrode of the pixel capacitor 14 is connected to a common line C2 connected to a VCOM circuit (counter electrode driving means) 26B, and a common voltage (counter electrode) generated by the VCOM circuit 26B via the common line C2. Signal) V _COM2 is applied.

When the scanning line G _{m1 + 1} ~G _{m1 + m2} is being in the selected state is sequentially high voltage, each corresponding thin film transistor 12 is turned ON, the signal line S ₁ to S _n corresponding to the respective display pixels When the voltage is applied, display data for one line is written, and one image is displayed on the liquid crystal display panel 10B.

That is, in the liquid crystal display device 1 of this embodiment, the connected signal lines S ₁ to S _n to one of a source driver circuit 22 are wired in common liquid crystal display panel 10A, to 10B, driven by the source driver circuit 22 Is done.

  The inversion RGB generation circuit 30 extracts the horizontal synchronization signal H, the vertical synchronization signal V, and the composite synchronization signal CSY from the video signal input from the outside of the liquid crystal display device 1 and outputs them to the LCD controller 40. Further, each RGB color signal (RGB signal) included in the video signal is extracted, and the polarity of the RGB signal is periodically inverted based on the inversion control signal FRP input from the LCD controller 40 to obtain an RGB inversion signal (luminance signal). ) And output to the source driver circuit 22. If the input video signal is an analog signal, the inversion RGB generation circuit 30 first converts it into a digital signal.

  The LCD controller 40 controls the liquid crystal display panels 10A and 10B to display an image based on the video signal based on the horizontal synchronizing signal H, the vertical synchronizing signal V, and the composite synchronizing signal CSY input from the inverting RGB inverting circuit 30. I do.

Specifically, LCD controller 40 generates and outputs the inverted control signal FRP to control the polarity inversion of a display signal applied to the signal lines S ₁ to S _n to the inverting RGB generating circuit 30. Further, an inversion control signal FRP1 for controlling the polarity inversion of the common voltage V _COM1 applied to the common line C1 of the liquid crystal display panel 10A is generated and output to the VCOM circuit 26A, and also applied to the common line C2 of the liquid crystal display panel 10B. and it generates an inverted control signal FRP2 for controlling polarity inversion of the common voltage V _COM2 outputs a VCOM circuit 26B.

Furthermore, LCD controller 40 outputs to the source driver circuit 22 generates a horizontal control signal HC that controls the application timing of the display signal to the signal lines S ₁ to S _n. Further, the vertical control signal VC1 for controlling the application timing of the scanning signal (gate pulse) to the scanning lines G _{1 to} G _m1 is generated and output to the gate driver circuit 24A, and the scanning lines G _{m1 + 1 to} G _{m1 +} are also generated. A vertical control signal VC2 for controlling the application timing of the scanning signal (gate pulse) to _m2 is generated and output to the gate driver circuit 24B.

The source driver circuit 22 sequentially samples the inverted RGB signal (luminance signal) input from the inverted RGB generation circuit 30 based on the horizontal control signal HC input from the LCD controller 40, and applies the corresponding display signal voltage to the horizontal signal. for each scanning period, simultaneously applies to the signal lines S ₁ to S _n.

The gate driver circuit 24A sequentially applies scanning signals (gate pulses) to the scanning lines G _{1 to} G _m1 of the liquid crystal display panel 10A based on the vertical control signal VC1 input from the LCD controller 40. Further, the gate driver circuit 24B sequentially applies a scanning signal (gate pulse) to the scanning lines G _{m1 + 1 to} G _{m1 + m2} of the liquid crystal display panel 10B based on the vertical control signal VC2 input from the LCD controller 40. .

The VCOM circuit 26A generates a common voltage V _COM1 whose polarity is inverted based on the inversion control signal FRP1 input from the LCD controller 40, and applies it to the common line C1 of the liquid crystal display panel 10A. In addition, the VCOM circuit 26B generates a common voltage V _COM2 whose polarity is inverted based on the inversion control signal FRP2 input from the LCD controller 40, and applies it to the common line C2 of the liquid crystal display panel 10B.

  When the liquid crystal display device 1 configured as described above is driven in an inverted manner, conventionally, the liquid crystal display device 1 has been driven by a driving waveform as shown in FIG. That is, when line inversion driving is performed, drive control is performed with the driving waveform as shown in FIG. 5A, and when frame inversion driving is performed, driving control is performed with the driving waveform shown in FIG. It was. Hereinafter, the inversion driving based on the driving waveform of FIG. 9 is referred to as “conventional inversion driving”.

In the conventional inversion drive, as described above, the display on the signal line S is caused by the parasitic capacitors 18A,..., 18B,... Formed between the signal line S and the common lines C1, C2. The signal and the waveforms of the common voltages V _COM1 and V _COM2 on the common lines C1 and C2 are deteriorated, resulting in the deterioration of the image quality of the display images of the liquid crystal display panels 10A and 10B and the waste of power consumption.

In the present embodiment, by devising a control method for inversion driving, waveform deterioration of the display signals and the common voltages V _COM1 and V _COM2 due to the parasitic capacitances 18A and 18B is suppressed. It is intended to reduce.
Hereinafter, four specific driving methods of this embodiment will be described in order.

<First Embodiment>
First, the first embodiment will be described.
In the first embodiment, the liquid crystal display panels 10A and 10B are driven by line inversion.

FIG. 4 is a diagram for explaining inversion drive control of the liquid crystal display device 1 in the first embodiment, and shows a drive waveform in one frame period. In the figure, with the horizontal axis as the time axis, the scanning timing of the scanning line G (gate scan), the display signal (source output) applied to the signal line S, and the common voltages V _COM1 and V _COM2 are shown in order from the top. ing. However, an example in which both “m1” and “m2” are even numbers of 2 or more is shown.

As shown in the figure, in the first embodiment, the polarities of the display signal and the common voltages V _COM1 and V _COM2 are inverted for each scanning line G and also for each frame period. The common voltages V _COM1 and V _COM2 are always set so that the polarities are opposite to each other. That is, the common voltages V _COM1 and V _COM2 are reversed in polarity at the same time and reversed in polarity to each other.

In order to drive the liquid crystal, the polarity of the common voltage V _COM and the display signal of the liquid crystal display panel which is a display target (scanned) is must be the opposite. For this reason, the display signal is set so that the polarity is opposite to the common voltage V _COM1 during the first screen display period, and the polarity is opposite to the common voltage V _COM2 during the second screen display period.

The polarity inversion of these display signals and common voltages V _COM1 and V _COM2 is controlled by the LCD controller 40. Specifically, the inversion control signals FRP, FRP1, and FRP2 generated by the LCD controller 40 are used. Is appropriately set and controlled to control the operations of the inverted RGB generation circuit 30 and the VCOM circuits 26A and 26B.

That is, the LCD controller 40 generates and outputs the inversion control signals FRP1 and FRP2 so as to invert the polarities of the common voltages V _COM1 and V _COM2 in opposite phases to the VCOM circuits 26A and 26B, respectively. Further, with respect to the inverted RGB generating circuit 30, a display signal is in the first screen display period becomes opposite to the polarity of the common voltage V _COM1, to the polarity opposite to the common voltage _VCOM2 in the second screen display period Thus, the inversion control signal FRP is set and output.

As described above, in the first embodiment, the common voltages V _COM1 and V _COM2 are reversed in polarity so that the polarities are opposite to each other, so that the common voltages V _COM1 and V _COM2 are between the common line C1 when viewed from the signal line S side. The polarity of the parasitic capacitance 18A formed and the parasitic capacitance 18B formed between the common line C2 is always reversed. Therefore, the influence of the parasitic capacitance 18A on the display signal and the waveforms of the common voltages V _COM1 and V _COM2 and the influence of the parasitic capacitance 18B on the display signal and the waveforms of the common voltages V _COM1 and V _COM2 are offset. The waveform deterioration of the display signals and the common voltages V _COM1 and V _COM2 is suppressed, and as a result, the image quality of the display images on the liquid crystal display panels 10A and 10B is improved as compared with the conventional driving method.

  In addition, since the polarities of the parasitic capacitors 18A and 18B when viewed from the signal line S are opposite to each other, currents (charge / discharge currents) due to charging / discharging of the parasitic capacitors 18A and 18B that flow when polarity is inverted are opposite to each other. Thus, the power consumption for charging and discharging the parasitic capacitors 18A and 18B is reduced, and the power consumption of the liquid crystal display device 1 is reduced.

FIG. 4 shows the case where both “m1” and “m2” are even numbers of 2 or more. However, the same applies to the case of odd numbers, and polarity inversion is performed for each scanning line and each frame period. Thus, the polarity of each waveform is set. Specifically, for example, when “m1” is an odd number, the polarities of the waveforms corresponding to the scanning lines G _{m1 to} G _{m1 + m2} are reversed in the figure, and “m2” is an odd number. The polarity of each signal waveform corresponding to the last scanning line G _{m1 + m2} in one frame period is reversed.

Second Embodiment
Next, a second embodiment will be described.
In the second embodiment, the liquid crystal display panels 10A and 10B are driven by line inversion, but the polarity inversion period is changed according to the liquid crystal display panel to be displayed.

FIG. 5 is a diagram for explaining inversion drive control of the liquid crystal display device 1 in the second embodiment, and shows a drive waveform in one frame period. In the figure, with the horizontal axis as the time axis, the scanning timing (gate scanning) of the scanning line, the display signal applied to the signal line S, and the common voltages V _COM1 and V _COM2 are shown in order from the top. However, an example in which both “m1” and “m2” are even numbers of 2 or more is shown.

As shown in the figure, in the second embodiment, the common voltages V _COM1 and V _COM2 are inverted in polarity so that the polarities are always opposite to each other, and the polarity inversion period is the same as in the first embodiment. Control is performed differently depending on the liquid crystal display panel to be displayed. Specifically, in the same figure, the common voltages V _COM1 and V _COM2 are inverted in polarity for each scanning line in the first screen display period, and are inverted for every two scanning lines in the second screen display period. That is, the polarity inversion period in the second screen display period is twice the polarity inversion period in the first screen display period.

Then, the polarity of the display signal is inverted so that the polarity of the common voltage of the liquid crystal display panel to be displayed is reversed. That is, the polarity of the display signal is inverted so that the polarity is opposite to the common voltage V _COM1 during the first screen display period, and the polarity is inverted so that the polarity is opposite to the common voltage V _COM2 during the second screen display period. Is done. Therefore, the polarity inversion period of the display signal in the second screen display period is also twice the polarity inversion period in the first screen display period.

Therefore, in the second embodiment, the LCD controller 40 causes the common voltages V _COM1 and V _COM2 to have opposite polarities to the VCOM circuits 26A and 26B, respectively, and for each scanning line in the first screen display period. The inversion control signals FRP1 and FRP2 are set and output so that the polarity is inverted and the polarity is inverted every two scanning lines in the second screen display period. Further, for the inverted RGB generation circuit 30, the polarity of the display signal is opposite to that of the common voltage _VCOM1 during the first screen display period, and the polarity is opposite to that of the common voltage _VCOM2 during the second screen display period. Thus, the inversion control signal FRP is set and output.

As described above, according to the second embodiment, the polarities of the common voltages V _COM1 and V _COM2 are opposite to each other as in the first embodiment described above. The waveform deterioration of the voltages V _COM1 and V _COM2 is suppressed, and the image quality of the display image is improved and the power consumption is reduced.

Further, since the number of times of polarity inversion of the common voltages V _COM1 and V _COM2 in the second screen display period of one frame period is reduced as compared with the conventional inversion driving, the liquid crystal display panels 10A and 10B are driven. Such reduction in power consumption is realized. However, generally, when the polarity inversion period is lengthened, the image quality of the display image is reduced accordingly. For this reason, in the second embodiment, for example, in a mobile phone having a main display and a sub display, the main display is the first screen, the sub display is the second screen, and only simple information such as time is displayed on the sub display. Therefore, the present invention is preferably applied to a case where high image quality is not required for the display image on the second screen, such as when high image quality is not required.

In FIG. 5, the polarity inversion period of the common voltages V _COM1 and V _COM2 in the second screen display period is set to twice the polarity inversion period in the first screen display period. The polarity inversion may be performed every 3 or more scanning lines in order to make the polarity inversion period 3 times or more. In this case, the longer the polarity inversion period, the more the image quality of the display image of the liquid crystal display panel 10B deteriorates, but the power consumption can be further reduced.

Further, the polarity reversal period of the common voltages V _COM1 and V _COM2 in the first screen display period may be made larger than the polarity reversal period in the second screen display period. That is, if the image quality of the liquid crystal display panel 10A for the first screen may be reduced depending on the application, for example, polarity inversion is performed for each of a plurality of scanning lines in the first screen display period, and the first screen display period is displayed. The polarity inversion period may be longer than the polarity inversion period in the second screen display period. Furthermore, the polarity inversion may be performed for each of the same or different scanning lines not only in one display period but also in both the first screen display period and the second screen display period.

Further, FIG. 5 shows the case where both “m1” and “m2” are even numbers, but the same is true when the numbers are odd, and the polarity is inverted for each scanning line and each frame period. Thus, the polarity of each waveform is set. Specifically, for example, when “m1” is an odd number, the polarities of the waveforms corresponding to the scanning lines G _{m1 to} G _{m1 + m2} are reversed in the figure, and “m2” is an odd number. That is, the polarity of each signal corresponding to the last scanning line G _{m1 + m2} in one frame period is inverted in one scanning line.

<Third Embodiment>
Next, a third embodiment will be described.
In the third embodiment, the liquid crystal display panels 10A and 10B are driven by line inversion, but the polarity inversion period of the liquid crystal display panel that is not the display target is greater than the polarity inversion period of the liquid crystal display panel that is the display target. Also make it longer.

FIG. 6 is a diagram for explaining inversion drive control of the liquid crystal display device 1 in the third embodiment, and shows drive waveforms in one frame period. In the figure, with the horizontal axis as the time axis, the scanning timing of the scanning line G (gate scan), the display signal (source output) applied to the signal line S, and the common voltages V _COM1 and V _COM2 are shown in order from the top. ing. However, an example in which “m1” and “m2” are both even numbers is shown.

As shown in the figure, in the third embodiment, in each display period of the first screen display period and the second screen display period, the polarity inversion of the common voltage of the liquid crystal display panel that is not the display target is 2 or more. This is performed for each of a plurality of scanning lines. Specifically, in the figure, in the first screen display period, the polarity of the common voltage _VCOM1 of the liquid crystal display panel 10A of the first screen that is the display target is inverted for each scanning line, and becomes the display target. The polarity of the common voltage _VCOM2 of the liquid crystal display panel 10B on the second screen which is not displayed is inverted every two scanning lines. That is, the polarity inversion period of the common voltage V _COM2 is twice the polarity inversion period of the common voltage V _COM1 .

On the other hand, in the second screen display period, the polarity of the common voltage _VCOM2 of the liquid crystal display panel 10B of the second screen that is the display target is inverted for each scanning line, and the liquid crystal of the second screen that is not the display target. The polarity of the common voltage _VCOM1 of the display panel 10A is inverted every two scanning lines. That is, the polarity inversion period of the common voltage V _COM1 is twice the polarity inversion period of the common voltage V _COM2 .

In addition, the display signal is inverted so that the polarity of the common voltage of the liquid crystal display panel currently being displayed is reversed. That is, the display signal is inverted so that the polarity is opposite to that of the common voltage V _COM1 in the first screen display period, and is inverted so that the polarity is opposite to that of the common voltage V _COM2 in the second screen display period. . Therefore, the polarity of the display signal is inverted every scanning line.

That is, in the third embodiment, the LCD controller 40 inverts the common voltage V _COM1 for each scan line in the first screen display period and every two scan lines in the second screen display period with respect to the VCOM circuit 26A. The inversion control signal FRP1 is set so as to invert the signal to be output. Further, for the VCOM circuit 26B, a common voltage V _COM2, the first screen display period is inverted every two scan lines, an inversion control signal FRP2 as in the second screen display period is inverted for each operation line Generate and output. Then, for the inverted RGB generation circuit 30, the polarity of the display signal is opposite to that of the common voltage _VCOM1 during the first screen display period, and the polarity is opposite to that of the common voltage _VCOM2 during the second screen display period. The inversion control signal FRP is set and output.

Thus, according to the third embodiment, in each display period, since the respective polarity inversion cycle of the common voltage V _COM1, V _COM2 are different, a period in which the polarity of the common voltage V _COM1, V _COM2 are opposite to each other Arise. During this period, waveform deterioration of the display signals and the common voltages V _COM1 and V _COM2 due to the parasitic capacitances 18A and 18B is suppressed, so that the image quality of the display image is improved and the power consumption compared to the conventional inversion driving. A reduction is expected.

Further, since the polarity of the common voltage V _COM of the liquid crystal display panel which is not currently displayed is inverted every two scanning lines, the common voltages V _COM1 and V _COM2 in one frame period are compared with the conventional inversion driving. The number of times of polarity inversion is reduced, thereby realizing reduction in power consumption for driving the liquid crystal display panels 10A and 10B.

Note that FIG. 6 shows the case where both “m1” and “m2” are even numbers, but the case where both are odd numbers is basically the same, and the polarity is inverted every operation line and every frame period. The polarity of each waveform is set to. Specifically, for example, when “m1” is an odd number, the polarities of the waveforms corresponding to the scanning lines G _{m1 to} G _{m1 + m2} are reversed, and when “m2” is an odd number, 1 is set. The polarities of the signals corresponding to the last signal line G _{m1 + m2} in the frame period are reversed.

<Fourth embodiment>
Next, a fourth embodiment will be described.
In the fourth embodiment, unlike the above-described first to third embodiments, the liquid crystal display panels 10A and 10B are not subjected to line inversion driving, but only frame inversion driving is performed.

FIG. 7 is a diagram for explaining inversion drive control of the liquid crystal display device 1 according to the fourth embodiment. In the figure, with the horizontal axis as a time axis, the scanning timing (gate scan) of the scanning line G, the display signal applied to the signal line S, and the common voltages V _COM1 and V _COM2 are shown in order from the top.

According to the figure, one frame period includes a first screen display period in which the liquid crystal display panel 10A is a display target and a second screen display period in which the liquid crystal display panel 10B is a display target. In the fourth embodiment, the liquid crystal display panel 10A for the first screen inverts the common voltage V _COM1 every frame period and sequentially scans the scanning lines G _{1 to} G _m1 to display an image. In the liquid crystal display panel 10B of the second screen, the common voltage V _COM2 is inverted every N frame periods, and scanning lines G _{m1 + 1 to} G _{m1 + m2} are scanned to display an image. However, “N” is an odd number.

Specifically, in the first frame period, the scanning lines G _{1 to} G _m1 are sequentially scanned in the first screen display period to display an image on the liquid crystal display panel 10A, and the scanning line G _{m1 is} displayed in the second screen display period. _{+1 to} G _{m1 + m2} are sequentially scanned to display an image on the liquid crystal display panel 10B. That is, the image is redisplayed on both the liquid crystal display panels 10A and 10B.

In the second frame period to the Nth frame period, the scanning lines G _{1 to} G _m1 are scanned in the first screen display period, and the image on the liquid crystal display panel 10A is displayed again. In the second screen display period, the scanning lines G _{m1 + 1 to} G _{m1 + m2} are not scanned, that is, the image on the liquid crystal display panel 10B is not redisplayed, and the display image in the first frame period is continuously displayed. Is done.

In the (N + 1) th frame period, similarly to the first frame period, the scanning lines G _{1 to} G _m1 are sequentially scanned in the first screen display period, and the scanning lines G _{m1 + 1 to} G _m in the second screen display period. _{m1 + m2} is scanned in sequence, and the image is re-displayed on both the liquid crystal display panels 10A and 10B.

  That is, in the liquid crystal display panel 10A, the image is redisplayed every frame period, but in the liquid crystal display panel 10B, the image is redisplayed every N frame periods, that is, scanning of the scanning line G (gate scan). ) Is thinned out.

The common voltage V _COM1 applied to the counter electrode of the liquid crystal display panel 10A is inverted in polarity every frame period, and the common voltage V _COM2 applied to the counter electrode of the liquid crystal display panel 10B is inverted every N frames. The At this time, the common voltage V _COM2 is a frame period in which the scanning lines G _{m1 + 1 to} G _{m1 + m2} of the liquid crystal display panel 10B are scanned, that is, a frame period in which image display is performed (first frame period, first frame period). The polarity is inverted at the end of (N + 1) frame period,..., And the polarity is not inverted at the end of a frame period in which scanning is not performed, that is, a frame period in which no image display is performed.

Note that the common voltage V _COM2 includes a frame period in which the scanning is performed of the scan lines G _{m1 + 1} ~G _{m1 + m2} of the liquid crystal display panel 10B, the scanning of the scanning lines G _{m1 + 1} ~G _{m1 + m2} the next The polarity inversion may be performed at any time between these two frame periods.

As described above, according to the fourth embodiment, the number of times of polarity inversion of the common voltage V _COM2 for the liquid crystal display panel 10B of the second screen is reduced as compared with the conventional frame inversion. As a whole, power consumption for driving the display panels 10A and 10B is reduced. However, since the number of drawing frames per unit time is reduced by thinning the scanning of the scanning line (gate scanning), for example, when displaying a moving image, there is a disadvantage that a jerky image such as “frame advance” is formed. In the case of character display or still image display, there is almost no problem. For this reason, the fourth embodiment can be suitably applied to a case where a still image with a small amount of information such as character display is displayed on the liquid crystal display panel 10B of the second screen.

  In FIG. 7, the scanning of the scanning line S of the liquid crystal display panel 10B of the second screen is thinned out. However, the present invention is not limited to this, and the scanning of the scanning line S of the display panel 10A of the first screen may be thinned out. It can be determined appropriately according to the display images of the liquid crystal display panels 10A and 10B.

Here, since “N” is an odd number, when the polarity of the display signal is inverted every frame period, the polarity of the display signal is reversed between the first frame period and the (N + 1) th frame period. Thus, in each frame period (first frame period, (N + 1) th frame period,...) For scanning the scanning line of the liquid crystal display panel 10B of the second screen, the common voltage _VCOM2 and the display signal are opposite in polarity. became. However, when “N” is an even number, if the polarity of the display signal is inverted every frame period, the polarity of the display signal is the same in the first frame period and the (N + 1) th frame period. For this reason, when “N” is an even number, the polarity of the display signal is reversed between the first frame period and the (N + 1) th frame period, for example, by not inverting the polarity at the end of the Nth frame period. The polarity may be reversed so that

[Modification]
The application of the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the liquid crystal display device 1 having the two liquid crystal display panels 10A and 10B has been described. However, the liquid crystal display device 1 may have three or more liquid crystal display panels. In that case, each liquid crystal display panel is driven to be inverted as follows.

That is, in the first embodiment, at least one common voltage V _COM among the common voltages V _COM1 , V _COM2 , V _COM3 ,... Of each liquid crystal display panel is opposite in polarity to the other common voltage V _COM. Invert the polarity so that Then, the display signal, the common voltage V _COM and the polarity of the liquid crystal display panel which is the display target is inverted to be opposite.

In the second embodiment, the polarity of each common voltage _VCOM is inverted for each of a plurality of scanning lines during a display period in which a liquid crystal display panel that does not require high image quality is displayed.

In the third embodiment, the polarity of the common voltage _VCOM of the liquid crystal display panel currently being displayed is inverted for each scanning line during the display period in which each liquid crystal display panel is to be displayed, and other display objects are displayed. The polarity of the common voltage _VCOM of the liquid crystal display panel that is not used is inverted every plural scanning lines.

In the fourth embodiment, among the plurality of liquid crystal display panels, for example, for a liquid crystal display panel that displays a still image such as a character display, scanning lines are scanned for each of a plurality of frame periods, and a common voltage is displayed. the V _COM is inverted in polarity at every frame period of the plurality of. And, for other liquid crystal display panel, for scanning and common voltage V _COM of the polarity inversion of the scanning lines in each frame period.

1 is a schematic configuration diagram of a liquid crystal display device. 1 is an overall configuration diagram of a liquid crystal display device. The circuit block diagram of each liquid crystal display panel. FIG. 6 is a drive waveform diagram of each liquid crystal display panel in the first embodiment. The drive waveform figure of each liquid crystal display panel in 2nd Embodiment. The drive waveform figure of each liquid crystal display panel in 3rd Embodiment. The drive waveform figure of each liquid crystal display panel in 4th Embodiment. The block diagram of a display pixel. The drive waveform figure of the conventional liquid crystal display panel. Explanatory drawing of the parasitic capacitance formed between a signal line and a common line. The waveform diagram of the display signal and the common voltage V _COM affected by the parasitic capacitance. Explanatory drawing of the waveform degradation of the display signal and common voltage at the time of polarity reversal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 10A, 10B Liquid crystal display panel 12 Thin-film transistor (TFT)
14 pixel capacity (liquid crystal capacity)
14a Pixel electrode 14b Counter electrode 16 Auxiliary capacitance 18 Parasitic capacitance S (S1 to Sn) Signal line (source line)
G (G1-Gm1 _{+ m2} ) Scan line (gate line)
C (C1, C2) Common line 20 Driver circuit (drive circuit)
22 Source Driver Circuit 24A, 24B Gate Driver Circuit 26A, 26B VCOM Circuit 30 Inverted RGB Generation Circuit 40 LCD Controller

Claims (13)

A plurality of pixels arranged in a matrix near each intersection of a plurality of scanning lines and a plurality of signal lines and having pixel electrodes and auxiliary capacitance electrodes connected to the pixel electrodes, and disposed at positions facing the pixel electrodes In a liquid crystal display device comprising a plurality of liquid crystal display panels having a plurality of common lines that are connected to the counter electrodes and are connected to the auxiliary capacitance electrodes and intersect the plurality of signal lines.
At least some of the plurality of signal lines of each liquid crystal display panel are wired in common between the liquid crystal display panels,
Counter electrode driving means for applying a counter electrode signal whose polarity is inverted at a predetermined cycle to the common line of each liquid crystal display panel;
Scanning side driving means for sequentially selecting the plurality of scanning lines of each liquid crystal display panel within a frame and sequentially setting the liquid crystal display panels in a display period;
And each counter electrode signal applied to the counter electrode of each of the liquid crystal display panels has a timing at which the polarities are reversed to opposite polarities at the same time.   The liquid crystal display device according to claim 1, wherein the timings at which the counter electrode signals are inverted in polarity to each other are always the same.   The liquid crystal display device according to claim 1, wherein the polarity inversion period of each counter electrode signal is different for each display period in a frame.   In each of the display periods in the frame, a period of polarity inversion of the counter electrode signal with respect to the liquid crystal display panel set in the display period among the counter electrode signals is set to be constant. The liquid crystal display device according to claim 1.   In each display period, the period of polarity inversion of the counter electrode signal for the liquid crystal display panel that is not set in the display period among the counter electrode signals is the counter electrode signal for the liquid crystal display panel set in the display period. The liquid crystal display device according to claim 4, wherein the liquid crystal display device is set to be longer than a cycle of polarity inversion. A plurality of pixels arranged in a matrix near each intersection of a plurality of scanning lines and a plurality of signal lines and having pixel electrodes and auxiliary capacitance electrodes connected to the pixel electrodes, and disposed at positions facing the pixel electrodes In a liquid crystal display device comprising a plurality of liquid crystal display panels having a plurality of common lines that are connected to the counter electrodes and are connected to the auxiliary capacitance electrodes and intersect the plurality of signal lines.
At least some of the plurality of signal lines of each liquid crystal display panel are wired in common between the liquid crystal display panels,
Counter electrode driving means for applying a counter electrode signal whose polarity is inverted at a predetermined cycle to the common line of each liquid crystal display panel;
Scanning-side driving means for selecting one liquid crystal display panel of the plurality of liquid crystal display panels for each predetermined plurality of frames, selecting another liquid crystal display panel for each frame, and setting the selected liquid crystal display panel to a display period; ,
A liquid crystal display device comprising:   Of each of the counter electrode signals, the polarity inversion period of the counter electrode signal with respect to the one liquid crystal display panel is set to the predetermined plurality of frames, and the period of polarity inversion of the counter electrode signal with respect to the other liquid crystal display panel is set to be a frame. The liquid crystal display device according to claim 6, wherein each of the liquid crystal display devices is provided. A plurality of pixels arranged in a matrix near each intersection of a plurality of scanning lines and a plurality of signal lines and having pixel electrodes and auxiliary capacitance electrodes connected to the pixel electrodes, and disposed at positions facing the pixel electrodes A plurality of liquid crystal display panels each having a plurality of common lines that are connected to the counter electrodes and connected to the auxiliary capacitance electrodes and intersect the plurality of signal lines. At least a part of the plurality of signal lines of the panel is a driving method for driving a liquid crystal display device wired in common between the liquid crystal display panels,
An operation of applying a polarity inversion at a predetermined cycle to the common line of each liquid crystal display panel so that the counter electrode signal has at least a timing of simultaneously reversing the polarities to each other.
In the frame, each liquid crystal display panel is sequentially selected, and each liquid crystal display panel is sequentially set to a display period;
A method for driving a liquid crystal display device, comprising:   9. The method of driving a liquid crystal display device according to claim 8, further comprising an operation of controlling the timings of reversing the polarities of the counter electrode signals to opposite polarities at the same time.   9. The driving method of a liquid crystal display device according to claim 8, further comprising an operation of controlling the polarity inversion period of each counter electrode signal to be different for each display period in a frame.   In each of the display periods in the frame, an operation of controlling the constant electrode inversion period of the counter electrode signal with respect to the liquid crystal display panel set in the display period out of the counter electrode signals is included. The driving method of the liquid crystal display device according to claim 8. A plurality of pixels arranged in a matrix near each intersection of a plurality of scanning lines and a plurality of signal lines and having pixel electrodes and auxiliary capacitance electrodes connected to the pixel electrodes, and disposed at positions facing the pixel electrodes A plurality of liquid crystal display panels each having a plurality of common lines that are connected to the counter electrodes and connected to the auxiliary capacitance electrodes and intersect the plurality of signal lines. At least a part of the plurality of signal lines of the panel is a driving method for driving a liquid crystal display device wired in common between the liquid crystal display panels,
An operation of applying a counter electrode signal to the common line of each liquid crystal display panel by reversing the polarity at a predetermined period;
Selecting one liquid crystal display panel of the plurality of liquid crystal display panels for each predetermined plurality of frames, selecting another liquid crystal display panel for each frame, and setting the selected liquid crystal display panel to a display period;
A method for driving a liquid crystal display device, comprising:   And an operation of controlling the polarity of the counter electrode signal for the one liquid crystal display panel to be inverted every predetermined frames and the polarity of the counter electrode signal for the other liquid crystal display panel to be inverted every frame. The method for driving a liquid crystal display device according to claim 12.

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