WO2008053609A1 - Liquid crystal display and method for driving the same - Google Patents

Abstract

Left and right source lines (first and second signal lines) (SnL and SnR) are arranged on opposite sides of a pixel (P), and voltage signals having different polarities are respectively applied to the left and right source lines. With respect to a plurality of pixels (P) arranged between the source lines (SnL and SnR), the number of pixel electrodes (5) connected to the source line (SnL) through a switching device (4) is set equal to the number of pixel electrodes (5) connected to the source line (SnR) through a switching device (4).

Description

 Specification

 Liquid crystal display device and driving method thereof

 Technical field

 The present invention relates to an active matrix liquid crystal display device and a driving method thereof.

 Background art

 In recent years, an active matrix type liquid crystal display device in which pixels having switching elements such as thin film transistors (TFTs) and pixel electrodes are arranged in a matrix is known.

 Here, with reference to FIG. 6 and FIG. 7, a conventional liquid crystal display device of the above active matrix type will be described. FIG. 6 is a diagram for explaining a main configuration of a conventional liquid crystal display device, and FIG. 7 is an equivalent circuit diagram showing a pixel configuration of the conventional liquid crystal display device.

 [0004] As illustrated in FIG. 6, in a conventional liquid crystal display device, five signal wirings S1 to S5 and four scanning wirings G1 to G4 are arranged on a TFT glass substrate so as to be orthogonal to each other. A plurality of pixels are provided in a matrix on the TFT glass substrate. Each pixel is provided with a TFT and a pixel electrode Pe.

 More specifically, in each pixel, the source and gate of the TFT are connected to one of the signal wirings Sl to S 5 and one of the scanning wirings G1 to G4, respectively. On the other hand, a pixel electrode Pe is connected to the TFT drain. In this conventional liquid crystal display device, for example, in a pixel in which the source and gate of the TFT are connected to the scanning line G1 and the signal line S1, respectively, the scanning voltage applied to the scanning line G1 is set to a predetermined high level. Sometimes the TFT of that pixel is turned on.

 [0006] Further, in this pixel, the signal voltage from the signal wiring S1 is applied to the pixel electrode Pe via the drain of the TFT. Thereafter, when the scanning voltage is set to a predetermined low level, the TFT of the pixel is turned off, and the charge of the pixel electrode Pe is maintained.

[0007] As shown in FIG. 7, the conventional liquid crystal display device is provided with a source driver 51 and a gate driver 52, and the source driver 51 and the gate driver 52 are n (n is an integer). Signal lines Sl to Sn and m (m is an integer) scanning lines Gl to Gm It may be configured to output a signal voltage and a scanning voltage, respectively.

 [0008] In addition, in the conventional liquid crystal display device, the pixel capacitor unit C3 including the liquid crystal capacitor C1 and the additional capacitor C2 is provided for each pixel, and when the charge of the pixel electrode Pe is maintained, The corresponding signal voltage is held by the pixel capacitor C3.

 In detail, for example, in a conventional liquid crystal display device, a counter glass substrate disposed opposite to the TFT glass substrate and a whole surface of the counter glass substrate are covered with a liquid crystal layer sandwiched therebetween. And a counter electrode facing the pixel electrode Pe (not shown), and a liquid crystal capacitance C1 is formed between the pixel electrode Pe and the counter electrode. Further, the TFT glass substrate is provided with an additional capacitor wiring (not shown) below the pixel electrode Pe, and an additional capacitor C2 is formed between the pixel electrode Pe and the additional capacitor wiring. In each pixel, the signal voltage is held in the pixel capacitor C3.

 [0010] In the conventional liquid crystal display device configured as described above, the gate driver 52 sequentially outputs scanning signals from the scanning wiring G1 to the scanning wiring Gm, for example, for one row (one horizontal line). ) Of the TFTs are simultaneously turned on, and the signal voltage is input from the signal wirings Sl,... As a result, a signal voltage is applied to each pixel electrode Pe, and the transmissivity of the liquid crystal layer changes according to the potential difference between the pixel electrode Pe and the counter electrode, thereby realizing gradation display according to the signal voltage. .

 [0011] In addition, in the liquid crystal layer, if a DC voltage is continuously applied over a long period of time, its holding characteristics deteriorate. Therefore, the polarity of the signal voltage applied to the pixel electrode Pe from the signal wirings Sl,. For example, by reversing each frame (one horizontal period), a positive polarity voltage and a negative polarity voltage are alternately applied to the pixel electrode Pe, so-called AC driving is performed. In addition, the polarity here means the polarity of the voltage with respect to the counter electrode.

 However, as described above, when AC driving is performed to change the polarity to positive or negative for each frame as described above, the voltage held in the liquid crystal layer is asymmetric due to TFT characteristics and the like. Sexuality occurs. For this reason, if a voltage with the same polarity is applied to all the pixels on the display surface within one frame, a slight potential difference between the positive and negative polarities occurs. As a result, flickering force appeared on the display surface, resulting in a decrease in display performance.

Therefore, in the conventional liquid crystal display device, every horizontal line within one frame period. It is known that by performing line inversion driving for changing the polarity and dot inversion driving for changing the polarity for each pixel, the generation of the above-mentioned flickering force is reduced and the display performance is prevented from deteriorating. In line inversion driving and dot inversion driving, the display performance of the liquid crystal display device can be improved more easily by dot inversion driving compared to line inversion driving. In the case of Graphics Array), there were many line inversion drives.

 However, in a conventional liquid crystal display device having a high resolution display surface such as SVGA (Super Video Graphics Array), XGA (Extended Graphics Ar ray), or SXGA (Super Extended Graphics Array) or a large display surface, Most of the driving methods adopt dot inversion driving.

 Hereinafter, with reference to FIG. 8 and FIG. 9, the dot inversion driving in the conventional liquid crystal display device will be specifically described. FIG. 8 is a diagram illustrating an example of driving in the N frame in the conventional liquid crystal display device, and FIG. 9 is an example of driving in the (N + 1) frame in the conventional liquid crystal display device. It is a figure to do.

 [0016] As shown in FIG. 8 and FIG. 9, in the dot inversion drive, on the display screen of one frame,

 Since the positive polarity pixels (shown as 図 + 〃 in the figure) and negative pixels (shown as 〃-〃 in the figure) are alternately present, the generation of the above-mentioned flicker force can be reduced.

 That is, in dot inversion driving, the source driver 51 stores pixel data corresponding to a video signal that has also received controller power (not shown). When pixel data for one horizontal line is stored in the source driver 51, the gate driver In 52, the scanning voltage applied to the corresponding scanning wirings Gl to Gm is set to the noise level, and the corresponding TFT is turned on. At the same time, the source driver 51 applies the stored pixel data as a signal voltage to the corresponding signal wirings Sl to Sm.

In this dot inversion drive, the source driver 51 reverses the signal voltage applied to the pixel via the signal wirings Sl to Sm for each horizontal line, and in each adjacent signal wiring Sl to Sm. Also, the signal voltage has a reverse polarity. For this reason, in the dot inversion drive, for example, as shown in FIG. 8, the polarity of the pixel is opposite to the polarity of the adjacent pixel in the horizontal direction and the vertical direction in the figure, and the pixel of + polarity and polarity is 1 Above on the frame display screen They are mixed alternately in the horizontal and vertical directions.

 In the dot inversion driving, when displaying the next frame, the source driver 51 inverts the polarity of the signal voltage to each of the signal wirings Sl to Sm and outputs the inverted signal voltage. Therefore, as shown in Fig. 9, the polarity of each pixel is inverted from that of Fig. 8.

[0020] Further, in each pixel, a parasitic capacitance is generated between the pixel electrode Pe and the signal wiring. In the conventional liquid crystal display device, the voltage applied to the pixel changes due to the parasitic capacitance, In some cases, pixels could not emit light with the desired brightness.

 Hereinafter, the deterioration in display performance due to parasitic capacitance will be specifically described with reference to FIG. FIG. 10 (a) is a diagram for explaining the parasitic capacitance between the pixel electrode and the source line in the conventional liquid crystal display device, and FIG. 10 (b) is a diagram for explaining the voltage pull-in generated in the pixel. The

 As illustrated in FIG. 10A, in the pixel, a parasitic capacitance Cgl is generated between the pixel electrode Pe and the signal wiring SN. In this pixel, a parasitic capacitance Cg2 is generated between the pixel electrode Pe and the signal wiring (SN + 1) of the adjacent pixel. Further, in the pixel, parasitic capacitance exists also between the pixel electrode Pe and the scanning wiring provided in the vicinity.

 Therefore, as shown in FIG. 10 (b), in the pixel, when the signal voltage VSN is applied from the signal wiring SN to the pixel electrode Pe from the time point SO, the pixel applied to the pixel electrode Pe The voltage VP changes depending on the parasitic capacitance and the signal voltage VS (N + 1) applied to the signal wiring (SN + 1). That is, as shown in the figure, when the amplitude of the signal voltage VSN is Δν, the pixel voltage VP changes by Δν ′ without being stabilized at a constant voltage. As described above, in the pixel, due to the parasitic capacitance, a voltage pull-in occurs in the pixel voltage VP, the luminance changes, and the display performance deteriorates.

 The voltage change ΔV ′ is defined as Csou, where Csou is the parasitic capacitance between the pixel electrode Pe and the signal wiring SN, (SN + 1), which is obtained by the sum of the parasitic capacitance Cgl and the parasitic capacitance Cg2. AV '= CsouX AV / ∑C, where ∑C is the sum of all parasitic capacitances in the pixel.

Next, with reference to FIG. 11 and FIG. 12 as well, a specific description will be given of a decrease in display performance due to parasitic capacitance generated in a conventional liquid crystal display device when dot inversion driving is performed. . FIG. 11 is a graph showing a specific example of voltage waveforms in each part of the conventional liquid crystal display device when the single color display is performed, and FIG. 12 is the graph when the conventional color image is displayed when all the colors of RGB are displayed. It is a graph which shows the specific example of the voltage waveform in each part of this liquid crystal display device. In the following description, a case where four pixels respectively connected to four scanning wirings are driven by dot inversion will be described.

[0026] As shown in FIG. 11 (a), in the four pixels, a signal voltage of + polarity and polarity is alternately applied from the signal wiring with respect to the voltage applied to the counter electrode indicated by a dotted line in the drawing. ing.

 Further, as shown in FIG. 11 (b), the four pixels adjacent to each other in the wiring direction of the scanning wiring with respect to the above four pixels have the same potential as the voltage applied to the counter electrode. Signal voltage is applied from the signal wiring. Therefore, in the conventional liquid crystal display device, when RGB pixels that respectively display red (R), green (G), and blue (B) are sequentially provided along the arrangement direction of the scanning wiring, for example, Only the R pixel emits light with a luminance corresponding to the signal voltage shown in FIG. 11 (a), and a red display is performed.

 [0028] At this time, for example, in the uppermost R pixel on the display surface, the pixel voltage in each of the first and second frames indicated by "tl" and "t2" in FIG. In the signal voltage writing period, the signal voltage increases or decreases according to the signal voltage shown in Fig. 11 (a). Further, in the case of red display, during the period between the writing period tl and t2, that is, the writing period of the signal voltage for the pixels in the second to fourth stages, the voltage pull-in by the corresponding signal voltage is This occurs in the pixel voltage of the R pixel.

 Specifically, as shown in FIG. 11 (c), in the period between the write period tl and t2, for example, when a polar signal voltage is applied to the second stage pixel, the top stage The pixel voltage of the R pixel is lower than the signal voltage applied during the write period tl due to parasitic capacitance. Subsequently, when a + polarity signal voltage is applied to the third stage pixel, the pixel voltage of the uppermost R pixel is increased by the parasitic capacitance so as to return to the signal voltage applied in the writing period tl. In this way, voltage pull-in due to parasitic capacitance occurs with respect to the pixel voltage of the uppermost R pixel, and the luminance at that pixel changes.

[0030] On the other hand, in a conventional liquid crystal display device, for example, all RGB pixels emit light and white When color display is performed, as shown in FIGS. 12 (a) and 12 (b), signal voltages having different polarities are applied to the above four pixels and the four pixels adjacent to these pixels. It is. Also, for example, in the uppermost R pixel, the pixel voltage is the signal voltage writing period in the first and second frames indicated by “t3” and “t4” in FIG. In FIG. 12, it increases or decreases according to the signal voltage shown in FIG.

[0031] In addition, in the white display, unlike the red display, the signal voltage is written in the signal voltage writing period (the period between the writing periods t3 and t4) for the pixels in the second to fourth stages. Thus, as shown in Fig. 12 (c), the pixel voltage of the uppermost R pixel is not changed between the writing periods t3 and t4. A red signal is displayed at a desired luminance while maintaining a constant signal voltage. For example, when a polar signal voltage is applied to the second stage R pixel, the second stage G pixel adjacent to the second stage R pixel is simultaneously This is because a + polarity signal voltage is applied, which almost cancels out the voltage pulling force with respect to the pixel voltage of the uppermost R pixel.

 [0032] As described above, in the conventional liquid crystal display device, in the case where any one of RGB single color display and white display are performed by dot inversion driving, FIG. 11 (c) and FIG. As shown in (c), the pixel voltages in the same pixel differed, resulting in a difference in luminance value. As a result, the conventional liquid crystal display device has a problem in that the display performance of the pixel is different between the monochrome display and the white display and the display performance is deteriorated.

 [0033] In order to solve the above-described problems, conventional liquid crystal display devices include, for example, Japanese Patent Application Laid-Open No. 10-213808 and Japanese Patent Application Laid-Open No. 2003-140625. As can be seen, it has been proposed to provide a compensation wiring that suppresses the parasitic capacitance and compensates for a voltage change in the pixel. That is, in these conventional liquid crystal display devices, a parallel compensation wiring is provided for each signal wiring, and a compensation voltage having a polarity opposite to that of the signal voltage applied to the signal wiring is applied to the compensation wiring. In these conventional liquid crystal display devices, it has been possible to compensate for the voltage change due to the parasitic capacitance and prevent the display performance from being deteriorated.

 Disclosure of the invention

Problems to be solved by the invention By the way, in the liquid crystal display device, there is a demand for a large display screen and high definition! In particular, high-end products such as LCD TVs that can receive digital broadcasts are strongly required to achieve both large screens and high definition, and it is required to increase the number of pixels on the display surface. ! RU

 However, in the conventional liquid crystal display device as described above, when the number of pixels is increased, there are problems that display performance cannot be improved and power consumption increases significantly. There was a thing.

 More specifically, in the conventional liquid crystal display device, when the number of pixels is increased, the load on the signal wiring may be significantly increased. In other words, in the conventional liquid crystal display device, when performing the dot inversion driving or the line inversion driving, it is required to increase the + polarity and the polarity inversion frequency (that is, the driving frequency) as the number of pixels increases. As a result, the load on the signal wiring was significantly increased. As a result, in conventional liquid crystal display devices, when the number of pixels is increased, it becomes difficult to drive with dot inversion drive or line inversion drive, and the display surface of the liquid crystal display device is divided into a plurality of regions, top, bottom, left, and right Thus, dot inversion driving was performed for each divided area. For this reason, in the conventional liquid crystal display device, when the number of pixels is increased, luminance unevenness occurs at the boundary portion of the divided area or the boundary portion is visually recognized, thereby improving display performance. It was difficult.

 [0037] Further, in the conventional liquid crystal display device, the compensation wiring is provided for each pixel. However, the compensation wiring is not connected to the pixel electrode. Therefore, in the conventional liquid crystal display device, when the number of pixels is increased, the power that does not directly contribute to the information display increases, and the load on the signal wiring increases, which increases the power consumption. There was a point.

 In view of the above problems, the present invention provides a liquid crystal display device capable of improving display performance and reducing power consumption even when the number of pixels is increased, and a driving method thereof. The purpose is to do.

 Means for solving the problem

In order to achieve the above object, a liquid crystal display device according to the present invention includes a plurality of scanning wirings and a plurality of signal wirings arranged in a matrix, and intersections of the scanning wirings and the signal wirings. Switching element provided in the vicinity and connected to the switching element. A liquid crystal display device having a plurality of pixels arranged in a matrix and having a pixel electrode.

 The signal wiring is provided on both sides of the corresponding pixel so as to sandwich the pixel electrode in the wiring direction of the scanning wiring, and voltage signals having different polarities are applied to the signal wiring.

1 and second signal wiring are included, and

 In the plurality of pixels arranged between the first and second signal wirings, the number of the pixel electrodes connected to the first signal wiring through the switching element, and the second The number of the pixel electrodes connected to the signal wiring via the switching element is set to the same number.

In the liquid crystal display device configured as described above, the signal wiring includes first and second signal wirings that are provided on both sides of the pixel and to which voltage signals having different polarities are applied. Yes. Further, the number of pixel electrodes connected to the first and second signal wirings is set to the same number. As a result, unlike the above-described conventional example, even when the number of pixels is increased, when displaying one frame of information without dividing it into a plurality of regions, the same number of + polar pixels and polar pixels are used. be able to. As a result, unlike the conventional example, it is possible to prevent the occurrence of uneven brightness at the boundary between the divided areas and improve the display performance. In addition, when displaying one frame of information, it is not necessary to reverse the polarity of the first and second signal wirings. Unlike the conventional example, the load on the signal wiring is increased even when the number of pixels is increased. It can be prevented from becoming large. As a result, it is possible to prevent the generation of electric power that does not directly contribute to the information display, thereby reducing power consumption.

 In the liquid crystal display device, in the pixel, a parasitic capacitance generated between the pixel electrode and the first signal wiring, and between the pixel electrode and the second signal wiring. It is preferable that the generated parasitic capacitance is substantially the same.

In this case, in the pixel, the voltage can be easily prevented from changing due to the difference between the two parasitic capacitances, and the display performance can be reliably improved.

[0043] In the liquid crystal display device, it is preferable that voltage signals having the same magnitude are applied to the first and second signal lines. [0044] In this case, a voltage signal can be easily applied to each of the first and second signal wirings.

 [0045] In the liquid crystal display device, in the plurality of pixels arranged between the first and second signal lines, the pixel electrode is connected to the first and second signal lines. It may be connected alternately through elements.

In this case, a plurality of pixels can be driven by the same driving as the dot inversion driving, and the display performance can be improved reliably.

[0047] In the liquid crystal display device, the pixels display red (R), green (G), and blue (B) arranged along the direction of the scanning wiring, respectively. May be included.

 [0048] In this case, even when performing RGB all-color display or any single color display, it has excellent display performance that prevents luminance differences from occurring, and enables labor-saving color display A liquid crystal display device can be configured.

 [0049] Further, the driving method of the liquid crystal display device of the present invention is any one of the above driving methods of the liquid crystal display device,

 A voltage signal corresponding to information to be displayed is applied to one signal wiring of the first and second signal wirings, and to the other signal wiring of the first and second signal wirings, A voltage signal obtained by inverting the polarity of the voltage signal is applied simultaneously.

 [0050] In the driving method of the liquid crystal display device configured as described above, even when the number of pixels is increased, it is possible to prevent an increase in the load on the signal wiring, thereby improving display performance. It becomes possible to reduce power consumption.

 The invention's effect

 [0051] According to the present invention, it is possible to provide a liquid crystal display device capable of improving display performance and reducing power consumption even when the number of pixels is increased, and a driving method thereof. It becomes.

 Brief Description of Drawings

FIG. 1 is a cross-sectional view showing a configuration of a main part of a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is an equivalent circuit diagram showing a pixel configuration of the liquid crystal display device.

 FIG. 3 is a diagram for explaining an example of driving the liquid crystal display device in N frames.

 FIG. 4 is a diagram for explaining a driving example of the liquid crystal display device at the time of (N + 1) frame.

 FIG. 5 is a graph showing voltage waveforms at various parts during driving of the liquid crystal display device.

 FIG. 6 is a diagram illustrating a configuration of main parts of a conventional liquid crystal display device.

 FIG. 7 is an equivalent circuit diagram showing a pixel configuration of the conventional liquid crystal display device.

 FIG. 8 is a diagram for explaining an example of driving in N frames in the conventional liquid crystal display device.

 FIG. 9 is a diagram for explaining an example of driving at the time of (N + 1) frame in the conventional liquid crystal display device.

 [FIG. 10] (a) is a diagram for explaining the parasitic capacitance between the pixel electrode and the source line in the conventional liquid crystal display device, and (b) is a diagram for explaining voltage pull-in generated in the pixel. is there.

 FIG. 11 is a graph showing a specific example of a voltage waveform in each part of the conventional liquid crystal display device when monochrome display is performed.

 FIG. 12 is a graph showing specific examples of voltage waveforms in the respective parts of the conventional liquid crystal display device when RGB full-color display is performed.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments showing a liquid crystal display device of the present invention and a driving method thereof will be described with reference to the drawings. In the following description, the case where the present invention is applied to a transmissive liquid crystal display device will be described as an example.

FIG. 1 is a cross-sectional view showing a main part configuration of a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram showing a pixel configuration of the liquid crystal display device. In FIG. 1, the liquid crystal display device 1 of the present embodiment includes a pair of transparent substrates 2a and 2b made of a transparent glass material or a synthetic resin material, and a liquid crystal layer 3 sandwiched between the transparent substrates 2a and 2b. In the liquid crystal display device 1, the upper side of FIG. 1 is installed as the display surface side so that information such as characters and images can be displayed.

The transparent substrate 2a constitutes an array substrate, and the transparent substrate 2a includes a thin film transistor (hereinafter referred to as “TFT”) 4 and a pixel electrode 5 as a switching element. Is provided. That is, the pixel electrode 5 is disposed on the liquid crystal layer 3 side of the transparent substrate 2a with the insulating film 6 interposed therebetween. The TFT 4 includes a gate 4g, a source 4s, and a drain 4d, and the drain 4d is connected to the pixel electrode 5. An insulating film 6 and semiconductor layers 7 and 8 are provided between the gate 4g, the source 4s, and the drain 4d.

[0056] The transparent substrate 2b constitutes a CF (Color Filter) substrate. The transparent substrate 2b includes the counter electrode 9, red (R), green (G), and blue (B) colors. A color filter 10 is provided.

 [0057] For example, TN mode liquid crystal is used for the liquid crystal layer 3, and light from a backlight device (not shown) provided on the lower side (non-display surface side) of the transparent substrate 2a is irradiated. It is becoming like that. In the liquid crystal display device 1, the amount of light passing through the liquid crystal layer 3 is controlled by driving the liquid crystal layer 3 in units of pixels according to information to be displayed, and information is displayed on the display surface. Is done.

 Further, as shown in FIG. 2, the liquid crystal display device 1 includes a plurality of, for example, m (m is an integer) gate lines Gl to Gm, and a plurality of, for example, a plurality of, for example, a left side and a right side of the pixel P. It has 11 (n is an integer) source lines SlL to SnL and SlR to SnR. These gate lines G1 to Gm and the source lines SlL to SnL and SlR to SnR are provided so as to be orthogonal to each other and arranged in a matrix.

 In addition, the gate lines Gl to Gm constitute a scanning wiring and are connected to the gate driver 12. A gate voltage is sequentially applied from the gate driver 12 to the gate drivers Gl to Gm. The left and right source lines SlL to SnL and SlR to SnR constitute first and second signal lines, respectively, and are connected to the source driver 11. A source voltage (voltage signal) is applied to the source lines SlL to SnL and SlR to SnR from the source driver 11 in units of pixels.

[0060] The source driver 11 and the gate driver 12 are connected to a controller (not shown) to which a video signal of information to be displayed is input from the outside. The source driver 11 and the gate driver 12 are The controller is configured to operate in response to an instruction signal. That is, the gate driver 12 is connected to the gate drivers Gl to Gm by applying a gate voltage to the gate drivers Gl to Gm according to the instruction signal of the controller. The connected TFT4 is turned on or off.

 Further, the source driver 11 applies a source voltage corresponding to the video signal to the source lines SlL to SnL and SlR to SnR based on an instruction signal from the controller. In addition, as will be described later in detail, the source driver 11 inverts the polarity of the source voltage for each of the left and right source lines SlL to SnL and SlR to SnR for each frame, and has the same magnitude. The source voltage is output.

 In the liquid crystal display device 1, the plurality of pixels P are provided in a matrix.

 The pixel region of each of the plurality of pixels P is partitioned by two adjacent gate lines Gl to Gm and a pair of left and right source lines SlL to SnL and SlR to SnR. Specifically, for example, the pixel region of the pixel P in the first row X first column is partitioned by the gate lines Gl and G2 and the source lines S1L and SIR. Furthermore, red (R), green (G), and blue (B) arranged along the wiring direction of the gate lines Gl to Gm (the left-right direction in FIG. 2) are respectively applied to the plurality of pixels P. Contains RGB pixel P to be displayed.

 [0063] Further, the pixel P has TFT4 provided near the intersection of the gate lines Gl to Gm and the source lines SlL to SnL or SlR to SnR and the pixel electrode 5 (Fig. 1) connected to the TFT4. is doing. Further, the pixel P is provided with a pixel capacitor part Pc including a liquid crystal capacitor CLc and an additional capacitor Cs, and the source voltage applied from the source lines SlL to SnL or SlR to SnR is supplied to the pixel capacitor part Pc. It comes to hold.

 The liquid crystal capacitor CLc is formed between the pixel electrode 5 and the counter electrode 9 (FIG. 1). The additional capacitor Cs is formed between the pixel electrode 5 and an additional capacitor wiring (not shown) installed on the lower side of the pixel electrode 5. In addition to this description, for example, an auxiliary electrode may be provided to constitute a pixel capacitor unit including an auxiliary capacitor formed between the pixel electrode 5 and the auxiliary electrode.

[0065] Further, in each of the plurality of pixels P, a parasitic capacitance generated between the pixel electrode 5 and the corresponding source lines SlL to SnL and a source line SlR to SnR corresponding to the pixel electrode 5 are generated. The parasitic capacitances are substantially the same. That is, in the pixel P, in the corresponding pair of source lines SlL to SnL and SlR to SnR provided on both sides of the pixel P so as to sandwich the pixel electrode 5 in the wiring direction of the gate lines Gl to Gm, Corresponding The distance between the pair of source lines SlL to SnL and SlR to SnR is the same. Thus, by providing the pixel electrode 5 in the center of the corresponding pair of source lines SlL to SnL and SlR to SnR, in the pixel P, the pair of source lines S1L to SnL and SlR corresponding to the pixel electrode 5 is provided. Parasitic capacitance generated between each of these and SnR is configured substantially the same.

 [0066] Further, in the liquid crystal display device 1, in the plurality of pixels P arranged between the pair of source lines SlL to SnL and SlR to SnR, the pixels connected to the source lines SlL to SnL via TFT4 The number of electrodes 5 and the number of pixel electrodes 5 connected to the source lines SlR to SnR via TFT 4 are set to the same number. That is, in the liquid crystal display device 1, in each of the n pixel columns, the number of pixels connected to the left source lines SlL to SnL and the number of pixels connected to the right source lines SlR to SnR are the same. And

 Hereinafter, the operation of the liquid crystal display device 1 of the present embodiment configured as described above will be specifically described with reference to FIGS. 3 to 5 as well.

 FIG. 3 is a diagram for explaining an example of driving the liquid crystal display device in the N frame, and FIG. 4 is a diagram for explaining an example of driving the liquid crystal display device in the (N + 1) frame. FIG. 5 is a graph showing voltage waveforms at various parts during driving of the liquid crystal display device.

 As shown in FIG. 3, in the liquid crystal display device 1 of the present embodiment, for example, when displaying information of N frames, the source driver 11 is indicated by (+) and (1) in FIG. Polar source voltages are applied to the source lines SlL to SnL and SlR to SnR. Specifically, for example, when a gate voltage that turns on TFT4 is applied to the gate line G1, the source driver 11 applies a + polarity source voltage corresponding to the video signal to the source line S1L. In addition, the source voltage of the same polarity and the same magnitude is simultaneously applied to the source line SIR by inverting the + polarity source voltage. These + polarity and polarity source voltages have the same magnitude as the applied voltage to the counter electrode 9 (FIG. 1).

[0070] Subsequently, after the gate voltage that turns off TFT4 is applied to the gate line G1, the source driver 11 is turned on when the gate voltage that turns on TFT4 is applied to the gate line G2. Is a unipolar source voltage corresponding to the video signal for the source line SIR. Is applied to the source line S1L, and the source voltage having the same polarity as the positive polarity is simultaneously applied to the source line S1L. Thereafter, the same voltage application is performed, and the liquid crystal display device 1 displays N frames of information.

 [0071] Further, in the information display of N frames, the polarities shown in Table 1 below are obtained for each pixel P in the matrix form.

 [0072] [Table 1]

 Next, as shown in FIG. 4, when (N + 1) frame information is displayed, the source driver 11 uses a pair of source lines as shown in (+) and (1) in FIG. For SlL to SnL and SIR to SnR, a source voltage having a polarity opposite to that of the N frame shown in Fig. 3 is applied. Specifically, for example, when a gate voltage that turns on the TFT 4 is applied to the gate line G1, the source driver 11 applies a source voltage having a polarity corresponding to the video signal to the source line S1L. In addition, the source voltage of the above polarity is inverted to the source line SIR, that is, the source voltage of the same magnitude with + polarity is applied simultaneously

[0074] Subsequently, after the gate voltage that turns off the TFT4 is applied to the gate line G1, the source driver 11 is turned on when the gate voltage that turns on the TFT4 is applied to the gate line G2. Applies a + polarity source voltage according to the video signal to the source line SIR, and inverts the + polarity source voltage to the source line S1L. Are simultaneously applied. Thereafter, the same voltage is applied, and the liquid crystal display device 1 displays information of (N + 1) frames.

 Further, in the information display of this (N + 1) frame, the polarity shown in Table 2 below is obtained for each pixel P in the matrix form.

[0076] [Table 2] 1st row 2nd row 3rd row nth row

 1st line ― + ― +

2nd line +-+ 1

3rd line ― + ― +

:: M-th line + ― + ―

As described above, in the liquid crystal display device 1 of the present embodiment, the source driver 11 inverts the polarity of the source voltage for the pair of left and right source lines SlL to SnL and SlR to SnR for each frame. Output.

 Further, as apparent from Tables 1 and 2, in the liquid crystal display device 1 of the present embodiment, each pixel P is driven by the same drive as the dot inversion drive.

 Further, in the pixel P of the liquid crystal display device 1 of the present embodiment, the parasitic capacitance generated between the pixel electrode 5 and each of the pair of source lines SlL to SnL and SlR to SnR is substantially the same. It is composed. In addition, voltage signals having opposite polarities and the same magnitude are applied to the source lines SlL to SnL and SlR to SnR. Thereby, in the liquid crystal display device 1 of the present embodiment, it is possible to prevent the occurrence of voltage pull-in caused by the parasitic capacitance regardless of the display image of information.

 Specifically, for example, in the four pixels P provided between the source lines SnL and SnR, the source voltage shown in FIG. 5A is applied to the pixels P in the first row and the third row. Applied from source line Sn L. Further, the source voltage force S source line SnR shown in FIG. 5B is applied to the pixels P in the second and fourth rows. Thus, for example, in the pixel P in the first row, + polarity and polarity source voltages in the writing period in the first and second frames indicated by 〃T1 ”and“ T2 ”in FIG. Is applied from the connected source line SnL, and as shown in FIG. 5 (c), the pixel voltage of the pixel P in the first row depends on the source voltage applied from the source line SnL. Increase or decrease.

In addition, since the source voltages shown in FIGS. 5 (a) and 5 (b) are simultaneously applied to the source lines SnL and SnR, respectively, in each of the four pixels P, the two parasitic capacitances are applied. The negative effects of are offset. As a result, in the pixel voltage of each pixel P, voltage pull-in is prevented. For example, the pixel voltage of pixel P in the first row is written as shown in Fig. 5 (c). In the period between the periods Tl and T2, that is, the writing period for the pixels Ρ in the second to fourth rows, the applied source voltage can be held without increasing or decreasing. As a result, the pixels in the first row can be lit and displayed with a desired luminance.

 Furthermore, as shown in FIGS. 5 (a) and 5 (b), source voltages having opposite polarities are applied to the source lines SnL and SnR on both sides of each pixel P within one frame period. Therefore, it is possible to prevent the occurrence of voltage pulling due to parasitic capacitance regardless of the display image of information such as when displaying only one color of RGB or when displaying white. Therefore, it is possible to reliably prevent the display performance from deteriorating.

 In the liquid crystal display device 1 of the present embodiment configured as described above, both sides of the pixel P are provided on the source line (signal wiring) to which the source voltage (voltage signal) corresponding to the information to be displayed is applied. And left and right source lines SlL to SnL and SlR to SnR (first and second signal wirings) to which voltage signals having different polarities are applied. In addition, the number of pixel electrodes 5 connected to the source lines SlL to SnL and SlR to SnR is set to the same number. As a result, in the liquid crystal display device 1 of the present embodiment, unlike the conventional example in which the compensation wiring is installed, even when the number of pixels is increased, the display surface is not divided into a plurality of areas. When displaying information, it is possible to have the same number of positive and negative pixels. As a result, in the liquid crystal display device 1 of the present embodiment, it is possible to prevent the occurrence of luminance unevenness at the boundary portion of the divided area and the visual recognition of the boundary portion, and improve the display performance.

 Further, in the liquid crystal display device 1 of the present embodiment, as shown in FIG. 3 or FIG. 4, when one frame of information is displayed, the polarity of the source lines S1L to SnL and S1R to SnR is changed. There is no need to flip it. As a result, in the liquid crystal display device 1 of the present embodiment, unlike the conventional example, it is possible to prevent the load on the source lines SlL to SnL and SlR to SnR from increasing even when the number of pixels is increased. . Furthermore, unlike the above-described conventional example, the liquid crystal display device 1 of the present embodiment prevents the generation of power that does not directly contribute to information display. In combination with preventing the increase of the load of ~ SnR, the power consumption of the liquid crystal display device 1 can be reduced.

[0085] Further, in the liquid crystal display device 1 of the present embodiment, since RGB pixels are included, RGB Even when performing all-color display or any single color display, a liquid crystal display device that has excellent display performance that prevents the occurrence of a luminance difference and is capable of labor-saving color display is configured. Can do.

 [0086] It should be noted that the above embodiments are all illustrative and not restrictive. The technical scope of the present invention is defined by the claims, and all modifications within the scope equivalent to the configurations described therein are also included in the technical scope of the present invention.

 [0087] For example, in the above description, the case where the present invention is applied to a transmissive liquid crystal display device has been described. However, the liquid crystal display device of the present invention is not limited to this and is not limited to this. It can be applied to a liquid crystal display device of a type.

 [0088] In the above description, the force described for the case of the TN mode liquid crystal layer is not limited to this. The present invention is not limited to this. The so-called longitudinal electric field controls the alignment of the liquid crystal molecules in the liquid crystal layer VA ( The present invention can also be applied to a liquid crystal layer of a liquid crystal mode such as an IPS (In-Plane-Switching) mode in which the alignment of liquid crystal molecules is controlled by a liquid crystal mode such as a vertical-alignment mode or a lateral electric field.

 In the above description, the case where a thin film transistor is used as the switching element has been described. However, the switching element of the present invention is not limited to this, and other three terminals such as a field effect transistor or a thin film. A two-terminal switching element such as a diode can also be used.

 In the above description, in each of the plurality of pixels, the parasitic capacitance generated between the pixel electrode and each of the first and second signal lines is configured to be substantially the same, and the first In the above description, the voltage signals having the same polarity and opposite polarity are applied to the second signal wiring. However, the present invention applies two signals in which voltage signals having different polarities are applied to both sides of the pixel. If wiring is provided for each pixel and the number of pixel electrodes connected to each signal wiring through the switching element is set to the same number in a plurality of pixels arranged between the two signal wirings, It is not limited at all.

[0091] Specifically, the parasitic capacitance generated between the pixel electrode and each of the first and second signal wirings is obtained in advance by calculation, experiment, and the like. Voltage pull-in due to parasitic capacitance by appropriately changing the voltage applied to the corresponding signal wiring It is also possible to improve display performance by preventing adverse effects such as viewing.

 However, as described above, when the two parasitic capacitances on both sides of the pixel are configured to be substantially the same, the voltage of the pixel changes due to the difference between the two parasitic capacitances. This is preferable in that it can be easily prevented and the display performance of the liquid crystal display device can be reliably improved.

 [0093] As described above, when the same voltage signal is applied to the first and second signal wirings, the first and second signal wirings are This is preferable in that a voltage signal can be easily applied. Furthermore, it is also preferable in that the configuration of a drive circuit (source driver) for applying a signal voltage to each signal wiring or a controller for instructing a signal voltage to be applied to this drive circuit can be simplified.

 [0094] In the above description, in the plurality of pixels arranged between the first and second signal wirings, the pixel electrodes are connected to the first and second signal wirings via the switching elements. For example, the present invention is not limited to this. For example, the configuration may be such that every two pixel electrodes are connected to the first or second signal wiring.

 However, as described above, when the pixel electrodes are alternately connected, a plurality of pixels can be driven by the same driving as the dot inversion driving, and the display performance can be surely improved. It is preferable in that it can be performed.

 Industrial applicability

[0096] The liquid crystal display device and the driving method thereof according to the present invention can improve display performance and reduce power consumption even when the number of pixels is increased. It is effective for a liquid crystal display device having a Z or high-definition display surface and a driving method thereof.

Claims

The scope of the claims  [1] A plurality of scanning wirings and a plurality of signal wirings arranged in a matrix, a switching element provided near an intersection of the scanning wiring and the signal wiring, and a pixel electrode connected to the switching element A liquid crystal display device including a plurality of pixels provided in a matrix,  The signal wiring is provided on both sides of the corresponding pixel so as to sandwich the pixel electrode in the wiring direction of the scanning wiring, and voltage signals having different polarities are applied to the signal wiring. 1 and second signal wiring are included, and  In the plurality of pixels disposed between the first and second signal lines, the first The number of pixel electrodes connected to the signal wiring of 1 through the switching element and the number of pixel electrodes connected to the second signal wiring through the switching element are: A liquid crystal display device having the same number. [2] In the pixel, a parasitic capacitance generated between the pixel electrode and the first signal wiring and a parasitic capacitance generated between the pixel electrode and the second signal wiring are substantially 2. The liquid crystal display device according to claim 1, which is specifically the same. 3. The liquid crystal display device according to claim 1, wherein voltage signals having the same magnitude are applied to the first and second signal lines. [4] In the plurality of pixels arranged between the first and second signal wirings, the pixel electrodes are alternately connected to the first and second signal wirings via the switching elements. The liquid crystal display device according to any one of claims 1 to 3. [5] The pixel has red (R) and green (G) arranged along the wiring direction of the scanning wiring. 5. The liquid crystal display device according to claim 1, further comprising RGB pixels that respectively display blue and blue (B). [6] The method for driving a liquid crystal display device according to any one of claims 1 to 5,  A voltage signal corresponding to information to be displayed is applied to one signal wiring of the first and second signal wirings, and to the other signal wiring of the first and second signal wirings, A method for driving a liquid crystal display device, wherein a voltage signal obtained by inverting the polarity of the voltage signal is applied simultaneously.