JP2008197420A - Liquid crystal display device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of miniaturizing a chip size of a driver IC which controls the potential of a common electrode and the whole display device when switching, between binary potentials for every one frame, the potential of the common electrode arranged along a scanning line for every scanning line and performing an image display such that odd rows and even rows have reversed polarity to each other. <P>SOLUTION: With respect to the common electrodes 19S arranged along the scanning line 3a for every scanning line 3a, a plurality of common electrodes which adjoin each other among the common electrodes 19S having the same polarity are connected to the same common electrode main line 19M and control signals to the plurality of common electrodes 19S are supplied through one common electrode main line 19M. A number equivalent to the number of the common electrode main line 19M which is less than the number of the common electrodes 19S suffices for the number of output terminals of the driver IC required for controlling the common electrodes 19S, therefore, the chip size can be reduced as much as the reduced number and, as the result, the whole display device can be miniaturized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a liquid crystal display device configured to display an image by changing an alignment state of liquid crystal according to a voltage between a pixel electrode and a common electrode formed on the same substrate, and an electronic apparatus using the same. .

Conventionally, a liquid crystal display device is used for a display of a computer, a cellular phone, or the like. In this liquid crystal display device, display is performed by sequentially selecting and driving pixel electrodes arranged in a matrix. That is, by applying a voltage between the selected pixel electrode and the counter electrode opposite to the selected pixel electrode, the liquid crystal intervening between them is changed, and the display pattern is formed by changing the transmission characteristics. Yes.

As a method for driving these pixel electrodes, an active matrix system in which an applied voltage is controlled by a switch element is known. Among them, a TFT in which a switch element is formed is called a TFT.
In general, since it is necessary to make the liquid crystal AC, the polarity of the common electrode is inverted in one line cycle, thereby realizing AC alternating in the liquid crystal that is inverted in one line cycle.
However, in this way, in the method of reversing the polarity of the common electrode in one line cycle, each time the polarity is reversed, the charge and discharge of charges are repeated on the parasitic capacitance in the substrate on which the common electrode is formed. There is a problem that current consumption is large.

On the other hand, the pixel electrode and the common electrode are formed on the same substrate, and a so-called horizontal electric field is generated between the pixel electrode and the common electrode to change the alignment state of the liquid crystal. In a horizontal electric field type liquid crystal display device, a common electrode is provided along each scanning line, the common electrode is divided into even lines and odd lines, and the polarity is reversed between even lines and odd lines. In addition, a driving method has been proposed in which the polarity of the liquid crystal is inverted in one line cycle by inverting the polarity of the common electrode every frame (see, for example, Patent Document 1). In the case of this driving method, it is only necessary to invert the polarity of the common electrode for each frame, and the number of charge charges / discharges to / from the parasitic capacitance is reduced, so that current consumption can be reduced.
JP-A-8-298638

However, as described above, when the common electrode is divided into even-numbered lines and odd-numbered lines and the polarity is inverted every frame, the scanning signal is supplied to the scanning line from the time when the polarity of the common electrode is inverted. Since the time required for each of the display lines differs depending on the display line, the voltage of the common electrode changes due to leakage current in the substrate on which the common electrode is formed, and the effective value changes. Even when the same voltage is applied to the pixel electrode, there is a possibility that a luminance difference occurs between the display lines.
Therefore, the common electrode is divided for each line and the polarity is changed for each line, and the time required from when the polarity of the common electrode changes until the scanning line corresponding to the common electrode is driven is scanned. There has also been proposed a method for preventing the occurrence of a luminance difference between display lines by making them equal between lines.

However, as described above, when the control for inverting the polarity of the common electrode individually for each line is realized in the liquid crystal display device using the amorphous TFT, the signal for controlling each of the common electrodes provided for each line. A line is required. That is, for example, in the case of a 320-line display liquid crystal panel, a driver IC for driving the liquid crystal panel requires 320 control outputs corresponding to the control output for controlling the common electrode. As a result, there is a problem that the chip size increases and the cost increases.
Accordingly, the present invention has been made paying attention to the above-mentioned conventional unsolved problems, and provides a liquid crystal display device and an electronic apparatus capable of reducing the chip size and reducing the cost. It is aimed.

In order to solve the above-described problems, a liquid crystal display device according to the present invention includes a pixel electrode provided corresponding to each intersection of a plurality of scanning lines and a plurality of data lines, and the same substrate as the pixel electrode. A liquid crystal display device that displays an image in accordance with a voltage between the pixel electrode and the common electrode. A common electrode drive circuit for periodically switching and applying a binary predetermined voltage, wherein the plurality of common electrodes is a set of the same applied voltages, and one end of the plurality of common electrodes belonging to the set Are connected to a common common electrode main line, and the other end of the common electrode main line is connected to the output terminal of the common electrode driving circuit.

As a result, the number of signal lines for controlling the common electrode is reduced as much as one end of the plurality of common electrodes is combined into one common electrode main line, and accordingly, the wiring for these signal lines is reduced. The number of control output terminals for supplying these signals can be reduced. Therefore, it is possible to reduce the size of the IC in which the common electrode driving circuit for controlling the common electrode is built in and to reduce the number of wirings to be routed. The liquid crystal display device can be downsized.

In the liquid crystal display device described above, among the common electrodes to which the same voltage is applied, a plurality of adjacent common electrodes are connected to the common electrode main line.
Here, if a plurality of relatively distant common electrodes are collectively controlled, the longer the timing interval for driving the scanning lines corresponding to these common electrodes, the more affected by the leakage current and the like, the fluctuation of the effective value of the common electrode The amount can be large. However, since the plurality of relatively common electrodes are controlled together, the influence on the display image due to the control of the plurality of common electrodes can be reduced.

In the above liquid crystal display device, a scanning line driving circuit for applying a scanning signal for selectively driving the plurality of scanning lines, and a data signal are supplied to the data lines in the order corresponding to the scanning signal. A data line driving circuit, wherein the scanning line driving circuit supplies the scanning signals in a different order for each frame to a plurality of scanning lines corresponding to the common electrode belonging to the set, and drives the common electrode The circuit switches a voltage to be applied to the common electrode before switching from a non-selected state to a selected state for a scanning signal to a scanning line driven first among a plurality of scanning lines corresponding to the set. It is characterized by.

Here, when a plurality of common electrodes are controlled together, the time required from the time when the voltage of the common electrode is switched to the time when the scanning lines corresponding to these common electrodes are driven differs for each scanning line. Since the charge amount is different, there is a possibility that a difference occurs in the display state of the pixel such as brightness. However, the order in which the scanning signals are supplied to the plurality of scanning lines corresponding to one set is different for each frame, and is driven first among the plurality of scanning lines corresponding to the one set. Since the voltage of the common electrode corresponding to the one set is switched before the scanning signal to the scanning line is switched from the non-selected state to the selected state, the plurality of common electrodes are controlled simultaneously. It is possible to visually average differences in pixel display status such as brightness.

In the liquid crystal display device described above, the voltage applied to the common electrode is switched for each frame, and the scanning line driving circuit drives a plurality of scanning lines corresponding to the set in the one frame period. It is characterized by having a different order.
Thereby, it is possible to avoid the difference in the display state of the pixels due to the difference in the voltage of the common electrode between the frames to be averaged, and the display state can be averaged more accurately.
In the liquid crystal display device described above, the pixel electrode is connected to the corresponding data line via a switch element, and is supplied to the data line when the switch element is turned on by the scanning signal. A data signal is applied to the pixel electrode, and the switch element is made of amorphous silicon.

Here, in the case of a switch element made of amorphous silicon, it is difficult to form a drive circuit for driving the switch element together with the switch element on the same substrate, so it is necessary to route a common electrode. By connecting the electrodes together to one common electrode main line, the ratio of the common electrodes on the substrate can be reduced. Accordingly, the size of the liquid crystal display device can be reduced accordingly, and the number of signals for supplying voltage to the common electrode can be reduced. Therefore, the driver IC having a built-in drive circuit for controlling the common electrode can be used. The number of output terminals can be reduced, that is, the driver IC can be miniaturized.
An electronic apparatus according to the present invention includes the above-described liquid crystal display device.
As a result, in an electronic apparatus provided with a liquid crystal display device, an electronic apparatus capable of reducing the chip size and reducing the cost can be realized.

Embodiments of the present invention will be described below.
The liquid crystal display device according to the present embodiment is an IPS (In-Plane) among the horizontal electric field methods in which an electric field (lateral electric field) in the substrate surface direction is applied to liquid crystal to perform image display by controlling orientation.
This is a liquid crystal display device adopting a method called a switching method.
In the drawings referred to in the present embodiment, each layer and each member are displayed with different scales so that each layer and each member have a size that can be recognized on the drawing.

The liquid crystal display device of the present embodiment is a color liquid crystal device having a color filter on a substrate, one for three dots that output light of each color of R (red), G (green), and B (blue). This constitutes the pixel. Therefore, the display area which is the minimum unit constituting the display is referred to as “dot area”. A display area composed of a set of (R, G, B) dots is referred to as a “pixel area”.

FIG. 1 is a circuit configuration diagram of a plurality of dot regions formed in a matrix that constitutes the liquid crystal display device of the present embodiment. FIG. 2 shows an equivalent circuit of an arbitrary one-dot region of the liquid crystal display device 100.
FIG. 3A is a plan configuration diagram in an arbitrary one-dot region of the liquid crystal display device 100. FIG.
FIG. 6B is an explanatory diagram showing an arrangement relationship of optical axes of optical elements that constitute the liquid crystal display device 100. FIG. 4 is a partial cross-sectional configuration diagram taken along the line AA ′ of FIG.

As shown in FIG. 1, a pixel electrode 9 and a TFT 30 for switching control of the pixel electrode 9 are formed in a plurality of dot regions formed in a matrix that constitutes the image display unit 100 a of the liquid crystal display device 100. The data line 6 a extending from the data line driving circuit 101 is electrically connected to the source of the TFT 30. The data line driving circuit 101 supplies image signals S1, S2,..., Sn to each pixel via the data line 6a.

Further, the scanning line 3a extending from the scanning line driving circuit 102 is electrically connected to the gate of the TFT 30, and the scanning signal G1 is supplied from the scanning line driving circuit 102 to the scanning line 3a in a pulse manner at a predetermined timing. , G2,..., Gm are applied to the gate of the TFT 30 in a predetermined order. The pixel electrode 9 is electrically connected to the drain of the TFT 30. The switching element TFT 30 is turned on for a certain period by the input of scanning signals G1, G2,..., Gm, so that the image signals S1, S2,.
, Sn are written to the pixel electrode 9 at a predetermined timing.

Image signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 9 are constant between the pixel electrode 9 and the common electrode 19 facing the liquid crystal as shown in FIG. Hold for a period. Here, in order to prevent the held image signal from leaking, a storage capacitor 70 is provided in parallel with the liquid crystal capacitor _CLC formed between the pixel electrode 9 and the common electrode 19. The storage capacitor 70 is provided between the drain of the TFT 30 and the capacitor line 3 b set at the potential of the common electrode 19.

Next, a detailed configuration of the liquid crystal display device 100 will be described with reference to FIGS. 3 and 4.
First, the liquid crystal display device 100 includes a TFT array substrate 10 and a counter substrate 20 as shown in FIG.
The liquid crystal layer 50 is sandwiched between the TFT array substrate 10 and the liquid crystal layer 50.
And the counter substrate 20 are sealed between the substrates 10 and 20 by a sealing material (not shown) provided along an edge of a region where the counter substrate 20 faces. On the back side (the bottom side in the figure) of the counter substrate 20, the light guide plate 9
1 and a reflector (illuminating device) 90 including a reflector 92 is provided.

As shown in FIG. 3, in the dot region of the liquid crystal display device 100, data lines 6a extending in the Y-axis direction, and scanning lines 3a and capacitor lines 3b extending in the X-axis direction are wired in a substantially lattice shape in plan view. A pixel electrode 9 extending in the Y-axis direction in a substantially comb-like shape in plan view in a substantially rectangular region in plan view surrounded by the data line 6a, the scanning line 3a, and the capacitor line 3b, and the pixel electrode 9 and a common electrode 19 extending in the Y-axis direction so as to form a substantially comb-like shape in a plan view and mesh with 9. In the upper left corner of the dot region, columnar spacers 40 are provided to keep the liquid crystal layer thickness (cell gap) constant by separating the TFT array substrate 10 and the counter substrate 20 at a predetermined interval. .

In the dot area, a color filter 22 having substantially the same planar shape as the dot area is provided. In addition, a reflective layer 29 is provided that occupies a substantially lower half plane area of the extending area of the pixel electrode 9 and the common electrode 19 (an area on the “−Y” side among the areas divided in the Y-axis direction). The reflective layer 29 is formed by patterning a light reflective metal film such as aluminum or silver. As shown in FIG. 3, among the planar regions surrounded by the pixel electrode 9 and the common electrode 19, the planar region that overlaps the reflective layer 29 in plan is the reflective display region R of the dot region, and the remaining region is the transmissive display. Region T. As the reflective layer 29, it is preferable to use a surface provided with irregularities on the surface thereof to impart light scattering properties. With such a configuration, the visibility in reflective display can be improved.

The pixel electrode 9 has a substantially L-shaped base end portion 9a extending along the data line 6a and the capacitor line 3b,
A plurality (three in the figure) of strip electrodes 9c branched from the base end portion 9a and extending in the “−X” direction, and a plurality of strip electrodes extending in an oblique direction (“−X” / “+ Y” direction) 9d and a contact portion 9b extending from the base end portion 9a in the vicinity of the capacitance line 3b to the “−Y” side. The pixel electrode 9 is an electrode member formed by patterning a transparent conductive material such as ITO (indium tin oxide).

The common electrode 19 is formed at a position overlapping the scanning line 3a in a plane and extends in the X-axis direction, and extends in the X-axis direction. The common electrode 19 extends in the Y-axis direction along the side edge of the dot area. The base end portion 19b extends, and two strip electrodes 19c and three strip electrodes 19d extending from the base end portion 19b to the “+ X” side are configured. The two strip electrodes 19c are alternately arranged with the strip electrodes 9c of the pixel electrode 9, and extend in parallel to the strip electrodes 9c. On the other hand, the three strip electrodes 19d are alternately arranged with the strip electrodes 9d extending obliquely in the figure,
These strip electrodes 9d extend in parallel. The common electrode 19 is also formed using a transparent conductive material such as ITO.
The pixel electrode 9 and the common electrode 19 can be formed using a metal material such as chromium in addition to the transparent conductive material.

As shown in FIG. 3, in the dot region of the liquid crystal display device 100 of this embodiment, the extending directions of the strip electrodes 9c, 9d, 19c, and 19d constituting the pixel electrode 9 and the common electrode 19 are the same as the reflective display region R. The direction is different from that of the transmissive display area T. That is, the strip electrodes 9c and 19c disposed in the transmissive display region T are formed to extend in parallel with the X-axis direction, while the strip electrodes 9d and 19d disposed in the reflective display region R are the strip electrodes 9c and 19c. And extending in a direction (diagonal direction) intersecting with.

In the dot region shown in FIG. 3, a voltage is applied between the five strip electrodes 9c and 9d extending in the X-axis direction and the five strip electrodes 19c and 19d disposed between the strip electrodes 9c and 9d. The liquid crystal is driven by an electric field (lateral electric field) generated in the XY plane direction (substrate plane direction). Further, since the pixel electrode 9 and the common electrode 19 are configured as described above, lateral electric fields in different directions are formed in the transmissive display region T and the reflective display region R when a voltage is applied.

The TFT 30 is provided near the intersection of the data line 6a extending in the X-axis direction and the scanning line 3a extending in the Y-axis direction, and is an island-like amorphous partly formed in the plane region of the scanning line 3a. A semiconductor layer 35 made of a silicon film, a source electrode 6b formed to partially overlap the semiconductor layer 35 in a plan view, and a drain electrode 32 are provided. The scanning line 3 a functions as a gate electrode of the TFT 30 at a position overlapping the semiconductor layer 35 in plan view.

The source electrode 6 b of the TFT 30 is a substantially inverted L-shaped wiring in plan view that branches from the data line 6 a and extends to the semiconductor layer 35. The drain electrode 32 is electrically connected to the connection wiring 31a extending along the side edge of the dot region at the “−Y” side end, and the connection wiring 31a.
And is electrically connected to the capacitor electrode 31 formed at the end edge on the opposite side of the dot region. The capacitor electrode 31 is a conductive member having a substantially rectangular shape in a plan view formed so as to overlap with the capacitor line 3b in a plan view, and the contact portion 9b of the pixel electrode 9 is disposed on the capacitor electrode 31 so as to overlap with the plane. The capacitor electrode 31 and the pixel electrode 9 are electrically connected through a pixel contact hole 45 provided at the position. In addition, a storage capacitor 70 having the capacitor electrode 31 and the capacitor line 3b as electrodes is formed in a region where the capacitor electrode 31 and the capacitor line 3b overlap in a plane.

Next, looking at the cross-sectional structure shown in FIG. 4, the TFT array substrate 10 disposed opposite to each other.
And the counter substrate 20 are sandwiched with a liquid crystal layer 50. The outer surface side of the TFT array substrate 10 (
On the side opposite to the liquid crystal layer 50, a retardation plate 16 and a polarizing plate 14 are sequentially laminated, and a polarizing plate 24 is disposed on the outer surface side of the counter substrate 20. The phase difference plate 16 is a λ / 2 phase difference plate that imparts a phase difference of approximately ½ wavelength to transmitted light. By providing the phase difference plate 16, the display characteristics of the reflective display and the transmissive display can be aligned with, for example, normally black, so that a wide viewing angle characteristic can be obtained without adopting a special configuration for the device structure or the signal processing configuration. be able to.

The TFT array substrate 10 has a translucent substrate body 10A such as glass, quartz, or plastic as a base, and the inner surface side (the liquid crystal layer 50 side) of the substrate body 10A is a reflection made of a metal film such as aluminum or silver. The layer 29 is partially formed in the dot area. A first interlayer insulating film 12 made of a transparent insulating material such as silicon oxide is formed so as to cover the reflective layer 29. First
A scanning line 3a and a capacitor line 3b are formed on the interlayer insulating film 12, and a gate insulating film 11 made of a transparent insulating material such as silicon oxide is formed so as to cover the scanning line 3a and the capacitor line 3b.

A semiconductor layer 35 made of amorphous silicon is formed on the gate insulating film 11, and a source electrode 6b and a drain electrode 32 are provided so as to partially run over the semiconductor layer 35. The source electrode 6b and the drain electrode A capacitive electrode 31 is formed at a position facing the capacitive line 3 b in the same layer as the electrode 32. As shown in FIG. 3, the drain electrode 32 is formed integrally with the connection wiring 31 a and the capacitor electrode 31. The semiconductor layer 35 is opposed to the scanning line 3 a via the gate insulating film 11, and the scanning line 3 a constitutes the gate electrode of the TFT 30 in the facing region. The capacitor electrode 31 has the gate insulating film 11 together with the capacitor line 3b facing the capacitor electrode 31.
Is formed as a dielectric film.

A second interlayer insulating film 13 made of silicon oxide or the like is formed so as to cover the semiconductor layer 35, the source electrode 6 b, the drain electrode 32, and the capacitor electrode 31, and on the second interlayer insulating film 13, I
A pixel electrode 9 and a common electrode 19 made of a transparent conductive material such as TO are formed. A pixel contact hole 45 that reaches the capacitor electrode 31 through the second interlayer insulating film 13 is formed, and a part of the contact portion 9b of the pixel electrode 9 is embedded in the pixel contact hole 45, whereby the pixel electrode 9 and the capacitor electrode 31 are electrically connected. In the transmissive display region T and the reflective display region R, strip electrodes 9c and 9d and strip electrodes 19c and 19d are alternately arranged. The main line portion 19a of the common electrode 19 includes the semiconductor layer 35, the source electrode 6b, And the drain electrode 32 and the second interlayer insulating film 13 so as to face each other. An alignment film 18 such as polyimide is formed so as to cover the pixel electrode 9 and the common electrode 19.

On the other hand, a color filter 22 is provided on the inner surface side (liquid crystal layer 50 side) of the counter substrate 20, and an alignment film 28 such as polyimide is laminated on the color filter 22. The color filter 22 is preferably configured to be divided into two types of regions having different chromaticities within the dot region. As a specific example, a first color material region is provided corresponding to the planar region of the transmissive display region T, and a second color material region is provided corresponding to the planar region of the reflective display region R. First
It is possible to adopt a configuration in which the chromaticity of the color material region is larger than the chromaticity of the second color material region. By adopting such a configuration, it is possible to prevent the chromaticity of the display light from being different between the transmissive display region T where the display light is transmitted only once through the color filter 22 and the reflective display region R where the display light is transmitted twice. The display quality can be improved by aligning the appearance of the reflective display and the transmissive display.
Further, it is preferable that a planarizing film made of a transparent resin material or the like is further laminated on the color filter 22. As a result, the surface of the counter substrate 20 can be flattened to make the thickness of the liquid crystal layer 50 uniform, and it is possible to prevent the drive voltage from becoming non-uniform in the dot region and lowering the contrast.

The arrangement of each optical axis in the liquid crystal device of this embodiment is as shown in FIG. 3B, and the transmission axis 153 of the polarizing plate 14 on the TFT array substrate 10 side is arranged in parallel to the X-axis direction. The transmission axis 155 of the polarizing plate 24 on the counter substrate 20 side is arranged in a direction (Y-axis direction) orthogonal to the transmission axis 153 of the polarizing plate 14. Further, the alignment films 18 and 28 are rubbed in the same direction in a plan view, and the direction is a rubbing direction 151 shown in FIG. 3B. In the present embodiment, the rubbing direction 151 is the X-axis direction. With respect to the angle of about 20 °. Although any direction can be selected as the rubbing direction 151, it is assumed to be a direction that intersects with the main direction of the horizontal electric field formed between the pixel electrode 9 and the common electrode 19 (a direction that does not coincide). In this embodiment, the horizontal electric field direction 158 in the transmissive display region T is parallel to the Y-axis direction, and the horizontal electric field direction 157 in the reflective display region R is the horizontal electric field direction 158 and the rubbing direction 151 in the transmissive display region. It is located in the middle.

The relationship between the rubbing direction 151 and the transverse electric field directions 157 and 158 can be appropriately changed according to the retardation of the liquid crystal layer 50 and the optical axis arrangement of the polarizing plates 14 and 24. FIG.
It is not limited to what is shown in (b). In this embodiment, if the angle between the horizontal electric field direction 157 and the rubbing direction 151 in the reflective display region R is in the range of 20 ° to 60 °, the horizontal electric field direction 158 and the rubbing direction 151 in the transmissive display region T are formed. Angle is 60 ° ~ 85
Set in the range of °.

The liquid crystal display device 100 having the above configuration is an IPS liquid crystal device, and includes a TFT 30.
By applying an image signal (voltage) to the pixel electrode 9 via the substrate, an electric field in the substrate surface direction (Y-axis direction in FIG. 3 in plan view) is generated between the pixel electrode 9 and the common electrode 19, The liquid crystal is driven to display an image by changing the transmittance / reflectance for each dot.

Here, FIG. 5 and FIG. 6 are operation explanatory views of the liquid crystal display device 100 of the present embodiment. FIG.
FIG. 5A is a schematic plan view of a dot region showing the alignment state of the liquid crystal molecules 51 in a state where no voltage is applied to the pixel electrode 9 (non-selection state), and FIG. It is a schematic plan view of the dot area | region which shows the orientation state of the liquid crystal molecule 51 in the state (selection state) which was performed. FIGS. 6A and 6B are explanatory diagrams of the operation of the liquid crystal molecules 51 in the transmissive display region T and the reflective display region R, respectively.

As shown in FIG. 5A, in a state where no voltage is applied to the pixel electrode 9, the liquid crystal molecules 51 constituting the liquid crystal layer 50 are aligned substantially horizontally along the rubbing direction 151 between the substrates 10 and 20. It has become. As described above, the alignment films 18 and 28 facing each other with the liquid crystal layer 50 interposed therebetween.
Are rubbed in the same direction in plan view, the liquid crystal molecules 51 are horizontally aligned in one direction between the substrates. When an electric field is applied to the liquid crystal layer 50 in such an alignment state via the pixel electrode 9 and the common electrode 19, the width of the strip electrodes 9c and 19c in the transmissive display region T as shown in FIG. The electric field EFt along the direction (Y-axis direction) acts, and the liquid crystal molecules 51 are aligned along the Y-axis direction. On the other hand, in the reflective display region R, since the extending direction of the strip electrodes 9d and 19d is different from the strip electrodes 9c and 19c of the transmissive display region T, an electric field EFr in a direction different from the transmissive display region T is formed. The liquid crystal molecules 51 are aligned along that direction. That means
In the transmissive display region T, since the direction of the electric field EFt and the rubbing direction 151 form a relatively large angle, as shown in FIG. 6A, the liquid crystal molecules 51 are largely rotated when a voltage is applied.
On the other hand, in the reflective display region R, the direction of the electric field EFr and the rubbing direction 151 are smaller than those in the transmissive display region T. Therefore, as shown in FIG. The rotation angle of the molecule 51 is also reduced.

The liquid crystal display device 100 performs bright / dark display using birefringence based on the difference in the alignment state of the liquid crystal molecules 51, and voltage is applied between the transmissive display region T and the reflective display region R. By changing the operation of the liquid crystal molecules 51 at the time, the appropriate transmittance /
The reflectance is obtained.

Next, the display operation of the liquid crystal display device 100 having the above configuration will be specifically described with reference to FIG. FIG. 7 is an explanatory diagram of the operation of the liquid crystal display device 100. This figure shows an operation explanatory diagram (left side in the figure) in the reflective display and an operation explanatory diagram (right side in the figure) in the transmissive display. The arrows shown in FIG. 7 indicate light incident on the liquid crystal display device 100 and the liquid crystal display device 100.
It shows the polarization state of light traveling in the plane. Regarding the illustration of the arrow, the horizontal direction in FIG. 7 corresponds to the X-axis direction in FIG. 3, and the vertical direction corresponds to the Y-axis direction in FIG.

First, the transmissive display (transmission mode) on the right side of FIG. 7 will be described.
In the liquid crystal display device 100, the light emitted from the backlight 90 passes through the polarizing plate 14, is converted into linearly polarized light parallel to the transmission axis 153 of the polarizing plate 14, and enters the retardation plate 16. Since the phase difference plate 16 is a so-called λ / 2 phase difference plate that gives a half-wave phase difference to the light that passes through the retardation plate 16, the linearly polarized light that has passed through the polarizing plate 14 is linearly polarized light that is orthogonal thereto. And is emitted from the phase difference plate 16 and enters the liquid crystal layer 50.

If the liquid crystal layer 50 is in an off state (non-selected state), the linearly polarized light is emitted from the liquid crystal layer 50 in the same polarization state as that at the time of incidence. The linearly polarized light passes through the polarizing plate 24 having the parallel transmission axis 155 and is visually recognized as display light, and the dot is brightly displayed.
On the other hand, if the liquid crystal layer 50 is in the on state (selected state), the incident light is given a predetermined phase difference (λ / 2) by the liquid crystal layer 50 and is converted into linearly polarized light rotated 90 ° from the polarization direction at the time of incidence. And emitted from the liquid crystal layer 50. Then, it is absorbed by the polarizing plate 24 having a transmission axis 155 orthogonal to the linearly polarized light, and the dot is darkly displayed.

Next, the reflective display on the left side of FIG. 7 will be described.
In the reflective display, light incident from above (outside) the polarizing plate 24 passes through the polarizing plate 24, is converted into linearly polarized light parallel to the transmission axis 155 of the polarizing plate 14, and enters the liquid crystal layer 50. At this time, if the liquid crystal layer 50 is in an OFF state, the linearly polarized light is in the same polarization state and the liquid crystal layer 5
It is emitted from 0 and reaches the reflection layer 29. Then, the light reflected by the reflective layer 29 passes through the liquid crystal layer 50 again and returns to the polarizing plate 24. Since the linearly polarized light is linearly polarized light parallel to the transmission axis 155 of the polarizing plate 24, the linearly polarized light is viewed through the polarizing plate 24, and the dot is brightly displayed.

On the other hand, if the liquid crystal layer 50 is on, the linearly polarized light incident on the liquid crystal layer 50 is
Is given a predetermined phase difference (λ / 4), converted into clockwise circularly polarized light, and reaches the reflective layer 29. When the clockwise circularly polarized light is reflected by the reflective layer 29, the rotation direction viewed from the polarizing plate 24 side is reversed, so that the light incident on the liquid crystal layer 50 from the reflective layer 29 becomes counterclockwise circularly polarized light. Yes. Thereafter, the counterclockwise circularly polarized light is converted into linearly polarized light having a polarization direction orthogonal to the polarization direction at the time of incidence by the action of the liquid crystal layer 50 and reaches the polarizing plate 24. Then, the linearly polarized light that reaches the polarizing plate 24 is absorbed by the polarizing plate 24 having the transmission axis 155 orthogonal to the polarization direction, and the dots are darkly displayed.

As described above, the liquid crystal display device 100 according to the present embodiment includes the pixel electrode 9 and the common electrode 19 described above, so that the liquid crystal layer 5 is in a state where a voltage is applied to the pixel electrode 9 (selected state).
The phase difference imparted to the light passing through 0 can be made different between the transmissive display area T and the reflective display area R. Thereby, the difference in display quality between the transmissive display and the reflective display due to the optical path difference between the transmissive display area T and the reflective display area R can be eliminated, and a high-quality display can be obtained in both the transmissive display and the reflective display. It is supposed to be.

Next, the arrangement state of the common electrode 19 in the liquid crystal display device 100 having the above-described configuration will be described with reference to FIGS.
As shown in FIG. 1, the common electrode 19 extends substantially in parallel with the scanning line 3a and is disposed corresponding to each of the scanning lines 3a. The common electrode 19S provided for each scanning line 3a.
In (1) to 19S (m), every two adjacent common electrodes 19S are connected to one common electrode main line 19M. That is, in the case of FIG. 1, the common electrodes 19S (1) and 19S
S (3) is connected to one common electrode main line 19M (1). Similarly, the common electrode 19S (
2) and 19S (4) are connected to one common electrode main line 19M (2).

These common electrodes 19S (1) to 19S (m) are provided for each of the scanning lines 3a (1) to 3a (m).
These are arranged substantially in parallel along the scanning lines, for example, as shown in FIG.
At the right end in FIG. 8, every two adjacent common electrodes 19S are connected to one common electrode main line 19M. The common electrode main line 19M is a driver IC described later.
It is connected to the. On the other hand, each of the scanning lines 3a is directly connected to the driver IC.

That is, the common electrode 19S is provided for each scanning line, but is connected to the driver IC via the common electrode main line 19M. Therefore, the common electrode 19S (for each scanning line)
The output terminals of the driver IC necessary for controlling 1) to 19S (m) may be half of the number of output terminals necessary for driving the scanning lines. That is, for example, in the case of a 320-line display liquid crystal display device, originally 320 pieces are necessary, but half of that is 160 pieces.

The common electrode main line 19 </ b> M is driven by the common electrode drive circuit 103. The common electrode driving circuit 103 is actually combined with the scanning line driving circuit 102 for driving the scanning line 3a.
It is built in one driver IC chip and mounted on the periphery of the image display unit 100 a of the TFT array substrate 10. A data line driving circuit 101 for driving the data lines 6a is built in the driver IC chip and mounted on the TFT array substrate 10 in the peripheral portion of the image display unit 100a. The data line driving circuit 101, the scanning line driving circuit 102, and the common electrode driving circuit 103 are controlled by a display control circuit 104.

According to the control signal from the display control circuit 104, the common electrode driving circuit 103 has a binary amplitude level of a predetermined potential for each common frame as shown by L1 in FIG. A common electrode control signal whose polarity is switched between a high potential and a low potential is supplied. At this time, the common electrode main lines 19M (1), 19M (3),... Corresponding to the common electrodes 19S (1), 19S (3), 19S (5),. 2),
Common electrode main lines 19M (2), 19M (4) corresponding to 19S (4), 19S (6),.
... and a common electrode control signal having a reverse polarity is supplied.

The polarity of the common electrode driving circuit 103 is switched by a scanning signal output circuit 102a described later.
Is output in synchronization with the output timing of the scanning signal for driving the scanning lines in the order of arrangement.
As described above, the paired common electrodes 19S (1) and 19S (3) are connected to one common electrode main line 19M (1) and connected to the paired common electrodes 19S (1) and 19S (3). On the other hand, since the same common electrode control signal is supplied, the potentials of the common electrodes 19S (1) and 19S (3) change at the same timing.

Therefore, among the scanning lines 3a corresponding to the common electrode 19S forming a pair, the common electrode 19S has a timing that is a predetermined time earlier than the timing at which the scanning line 3a that is driven first is driven. A common electrode control signal for inverting the polarity is output. In the case of FIG. 1, the common electrodes 19S (1) and 19S (3), 19S (2) and 19S (4), 19S (5) and 19S (7), 19S (6) and 19S (8),. Are paired, the scanning line 3 corresponding to the common electrodes 19S (1) and 19S (3) from the scanning signal output circuit 102a.
The timing at which the scanning signal for a (1) is output, common electrodes 19S (2) and 19S (
4) the timing at which the scanning signal for the scanning line 3a (2) corresponding to 4) is output, the common electrode 1
Timing at which the scanning signal for the scanning line 3a (5) corresponding to 9S (5) and 19S (7) is output, and the scanning signal for the scanning line 3a (6) corresponding to the common electrodes 19S (6) and 19S (8) Is output to the corresponding common electrode main line 19M.

As a result, the time required from when the polarity of the common electrode main line 19M is inverted to when any of the scanning lines 3a corresponding thereto is driven is the same between the common electrode main lines 19M.
The scanning line driving circuit 102 scans the scanning line 3 according to the control signal from the display control circuit 104.
A scanning signal G having a predetermined voltage for selecting a is output at a predetermined timing by switching the output scanning line 3a. Further, the scanning signal G is output at a timing after the polarity of the common electrode 19S corresponding to the scanning line 3a to be selected is inverted. At this time, as shown by L2 in FIG. 9, the voltage level on the low potential side of the scanning signal G is changed according to the polarity of the common electrode 19S corresponding to the scanning line 3a to be selected, and the liquid crystal applied voltage is changed. To be constant. In other words, the voltage level on the low potential side is changed in synchronism with the inversion of the polarity of the common electrode control signal to the common electrode 19S, and a scanning signal that becomes a high potential in a pulse manner is output at a predetermined timing. Further, according to the switching signal from the display control circuit 104, the output destination of the scanning signal G is switched for each frame, and the driving order of the scanning lines 3a is switched.

FIG. 10 is a block diagram illustrating a configuration of the scanning line driving circuit 102.
The scanning line driving circuit 102 outputs a scanning signal for sequentially selecting the scanning lines 3a in the arrangement order based on a control signal such as a timing signal from the display control circuit 104. An output circuit 102 a and a switching circuit 102 b that switches the output destination of the scanning signal from the scanning signal output circuit 102 a based on the switching signal from the display control circuit 104 and supplies the scanning signal to the corresponding scanning line 3 a are provided.

Here, as described above, in the present application, every two adjacent common electrodes 19S are connected to one common electrode main line 19M, and the potential of the two common electrodes 19S is controlled by one common electrode control signal. Is done. That is, the common electrode 19S (1), the common electrode 19S (3), and the common electrode 19S
(2) and the common electrode 19S (4),... Form a pair, and the common electrodes 19S are applied with voltages having opposite polarities on the odd and even lines, so that the applied voltages have the same polarity. The common electrodes 19S make a pair, the same common electrode control signal is supplied to them, and the same voltage is applied.

The switching circuit 102b switches the output destination of the scanning signal G based on the switching signal from the display control circuit 104. When the normal connection is instructed by the switching signal, the scanning signal output circuit 1
The scanning signal from 02a is output to the corresponding scanning line 3a as it is. On the other hand, when switching of the connection destination is instructed by the switching signal, the output destination of the scanning signal is set as the pair of common electrodes 19S.
Are output to the scanning line 3a corresponding to the other. That is, in FIG. 1, since the common electrode 19S (1) corresponding to the first scanning line 3a (1) is paired with the common electrode 19S (3), the first scanning line 3a (1). Is output to the scanning line 3a (3) corresponding to the common electrode 19S (3). Similarly, the common electrode 19S corresponding to the scanning line 3a (2).
Since (2) is paired with the common electrode 19S (4), the scanning signal for the scanning line 3a (2) is output to the scanning line 3a (4) corresponding to the common electrode 19S (4). Similarly, the scanning signal for the scanning line 3a (3) is output to the scanning line 3a (1), and the scanning signal for the scanning line 3a (4) is output to the scanning line 3a (2). That is, normally, the scanning line 3a is changed to 3a (1),
3a (2), 3a (3), 3a (4),... Are selected in this order, but when a switching instruction is given, 3a (3), 3a (4), 3a (1), 3a (2), Select in order.

Based on the control signal and image data from the display control circuit 104, the data line driving circuit 103 sequentially switches the data line 6a with respect to the data line 6a at a timing specified by the control signal, and a voltage signal corresponding to the image data. An image signal S consisting of Further, the polarity of the image signal S is supplied for each data line 6a, and the polarity is inverted for each frame.
As a result, as shown in FIG. 9, a scanning signal G having a predetermined voltage is supplied to the scanning line 3b (L
2) When the TFT 30 is turned on, the image signal S supplied from the data line 6a is written to the pixel electrode 9 to change the pixel electrode potential (L3), and the pixel electrode potential and the common electrode corresponding to the image signal S are changed. A voltage difference from the potential of 19S is applied to the liquid crystal layer 50. In FIG. 9, L
3 is a pixel electrode potential when the liquid crystal is ON when the alignment state of the liquid crystal layer 50 is a light transmission state, and L4 is a pixel electrode potential when the liquid crystal is OFF when the alignment state of the liquid crystal layer is a light blocking state.

The display control device 100 outputs a switching signal to the scanning line driving circuit 102. This switching signal alternately outputs a normal instruction and a switching instruction for switching the connection destination every two frames. When the switching instruction is output, the data line driving circuit 101 corresponding to this frame is displayed.
The order of image data to be supplied to is changed and output. That is, as described above, when a switching instruction is given, the scanning lines are driven in the order of 3a (3), 3a (4), 3a (1), 3a (2),. Thus, the arrangement order of the image data corresponding to each pixel is changed and output. That is, normally, the scanning lines 3a (1), 3a (2), 3a (3), 3a (
4), when outputting image data to the data line driving circuit 101 in the order of arrangement of the image data corresponding to the pixels connected thereto, and instructing switching, the scanning lines 3a (3), 3a (4)
Image data is output to the data line drive circuit 101 in the order of image data corresponding to the pixels connected to the pixels connected to the pixels 3a (1), 3a (2),.

Next, the operation of this embodiment will be described with reference to the timing chart of FIG. Note that in FIG. 11, pixels connected to the first and third scanning lines where writing with the same polarity is performed will be described.
The scanning line driving circuit 102 outputs the scanning signal G for sequentially selecting the scanning lines 3 a and switches the output destination of the scanning signal based on the switching signal from the display control circuit 104.

Assuming that the first frame image display is performed, the display control circuit 104 outputs a switching signal instructing normal connection.
For this reason, the scanning line driving circuit 102 sequentially outputs scanning signals G for sequentially selecting the scanning lines 3a in the arrangement order to the scanning lines 3a. Thereby, the scanning signal G is output in the order of the scanning line 3a (1), the scanning line 3a (2), the scanning line 3a (3), the scanning line 3a (4),.

The data line driving circuit 101 sequentially switches the data lines 6a and outputs an image signal corresponding to the image data input from the display control circuit 104 to the data lines 6a at a predetermined timing.
Here, a dot area corresponding to the intersection position of the scanning line 3a (1) and the first data line 6a, and a dot area corresponding to the intersection position of the scanning line 3a (3) and the first data line 6a, Pay attention to.
In FIG. 11, the thin solid line indicates the scanning signal to the scanning line 3a (1), and the thick solid line indicates the scanning line 3a.
The scanning signal to (3), the thin broken line is the pixel electrode potential of the dot area corresponding to the scanning line 3a (1),
The thick broken line represents the pixel electrode potential of the dot region corresponding to the scanning line 3a (3).

In the writing of the first frame, as shown in FIG. 11A, first, before the scanning signal is supplied to the scanning line 3a (1), the common electrode control signal to the common electrode main line 19M (1) is shared. When the polarities of the electrode 19S (1) and the common electrode 19S (3) (VCOM) are inverted, and then the scanning signal is supplied to the scanning line 3a (1) and the scanning line 3a (1) is selected, this scanning is performed. Line 3
The TFT 30 connected to a (1) is turned on. As a result, a positive potential is applied as an image signal from the data line 6a to the pixel electrode 9, and the TFT 30 connected to the scanning line 3a (1).
Liquid crystal capacitance C _LC as a pixel capacitance connected to the pixel electrode 9 during the period until the pixel is cut off.
Then, the storage capacitor 70 is charged, whereby the pixel electrode 9 is held at a positive potential corresponding to the image signal. During this time, the common electrode 19S (1) is at a predetermined low potential. As a result, a voltage difference between the pixel electrode 9 and the low potential common electrode 19S (1) acts on the liquid crystal layer 50,
In response to this, the alignment state of the liquid crystal changes, and an image display corresponding to the image signal is performed.

Subsequently, the second scanning line 3a (2) is selected (not shown), but this scanning line 3a is selected.
Before (2) is selected, the polarity of the common electrode 19S (4) together with the common electrode 19S (2) is changed by the common electrode control signal to the common electrode main line 19M (2) corresponding to the scanning line 3a (2). After switching and selecting the scanning line 3 a (2), the same operation as described above is performed, and the data line driving circuit 101 performs writing with a negative polarity on the pixel electrode 9.

Subsequently, when the third scanning line 3a (3) is selected, the liquid crystal capacitor _CLC and the storage capacitor 70 are charged in the same manner, and the pixel electrode 9 receives the image signal as shown by the thick broken line. It is held at a considerable positive potential. Since the common electrode 19S (3) corresponding to the scanning line 3a (3) is held at a low potential at the timing when the polarity of the common electrode 19S (1) changes, the pixel electrode 9 and the common electrode 19S ( The voltage difference from 3) acts on the liquid crystal layer 50.

Thereafter, the fourth scanning line 3a (4) is selected and operated in the same manner. When the fifth scanning line 3a (5) is selected, the fifth scanning line 3a (5) is selected. The drive signal to the common electrode main line 19M (3) to which the common electrode 19S (5) corresponding to the scanning line 3a (5) is connected changes to a low potential at a time before a predetermined time, and then the scanning is performed. The line 3a (5) is selected, and writing is performed in the same operation as described above. Thereafter, all the scanning lines 3 are processed in the same procedure.
a is driven, and writing to the pixel electrode 9 corresponding thereto is performed.

Next, when writing the second frame, as shown in FIG. 11B, the display control circuit 104 continuously outputs a switching signal instructing normal connection. Then, at the timing before the first scanning line 3a (1) is selected, the common electrode 19 corresponding to the scanning line 3a (1).
S (1) and the polarity of the scanning line 3a (3) are switched to a high potential at the same time, and scanning signals for sequentially selecting the scanning lines 3a from the scanning line driving circuit 102 are sequentially arranged in the order of the scanning lines 3a. Is output.

When the scanning line 3a (1) is selected, the TFT 30 connected to the selected scanning line 3a (1) is turned on, and a negative potential is applied to the pixel electrode 9 from the data line 6a as an image signal this time. In the period until the TFT 30 connected to the scanning line 3a (1) is cut off, the liquid crystal capacitor _CLC and the storage capacitor 70 connected to the pixel electrode 9 are charged, whereby the pixel electrode 9 is The negative potential corresponding to the signal is held. The voltage difference between the pixel electrode 9 and the common electrode 19S (1) acts on the liquid crystal layer 50.

Subsequently, before the scanning line 3a (2) of the second line is selected, the polarities of the common electrode 19S (2) and the common electrode 19S (4) are switched to a low potential, and then the scanning line 3a (2). After that, the same operation is performed, and in this case, writing with positive polarity is performed. Subsequently, when the third scanning line 3a (3) is selected, the liquid crystal capacitor _CLC and the storage capacitor 70 are similarly charged,
The pixel electrode 9 is held at a negative potential corresponding to an image signal. The pixel electrode 9 and the common electrode 1
A voltage difference from 9S (3) acts on the liquid crystal layer 50.
Subsequently, when writing the third frame, the display control circuit 104 outputs a switching signal instructing switching of the connection destination.

For this reason, the scanning line driving circuit 102 changes the output destination of the scanning signal for sequentially selecting each scanning line 3a and outputs it. In this case, since the common electrodes 19S (1) and 19S (3) and the common electrodes 19S (2) and 19S (4) are paired, the scanning signal to the scanning line 3a (1) is the scanning line 3a. To (3), the scanning signal to the scanning line 3a (2) is to the scanning line 3a (4), the scanning signal to the scanning line 3a (3) is to the scanning line 3a (1), and to the scanning line 3a (4). Are output to the scanning line 3a (2). Thereafter, the scanning lines 3a (5), 3a (6), 3a (7), 3a (8)
Are output in the order of the scanning lines 3a (7), 3a (8), 3a (5), 3a (6),.
In addition, the display control circuit 104 changes the arrangement order of the image data supplied to the data line driving circuit 101 to the pixel data to the pixels connected to the scanning line 3a (3) and the pixels connected to the scanning line 3a (4). Pixel data, pixel data to pixels connected to the scanning line 3a (1), scanning line 3a (2
) Are rearranged in the order of pixel data to the pixels connected to.

Therefore, in the third frame, as shown in FIG. 11C, first, the scanning signal output circuit 1
At a point before the scanning signal is output from 02a to the scanning line 3a (1), the common electrode 19S (1
) And the common electrode 19S (3) are switched to a low potential. In the scanning line driving circuit 102, the scanning signal to the scanning line 3a (1) output from the scanning signal output circuit 102a is
The output destination is switched by the switching circuit 102b and supplied to the scanning line 3a (3). Writing to the pixel electrode 9 corresponding to the scanning line 3a (3) is performed, and the pixel electrode 9 corresponds to an image signal. Maintained at a positive potential. A potential difference between the positive potential corresponding to the image signal of the pixel electrode 9 and the low potential of the common electrode 19S (1) acts on the liquid crystal layer 50.

Subsequently, after the polarity of the common electrode 19S (2) corresponding to the scanning line 3a (2) is switched to a high potential, the output destination of the scanning signal to the scanning line 3a (2) is switched and the scanning line Vg is switched. (4
) And operates in the same manner. In this case, writing with negative polarity is performed. Subsequently, when the output destination of the scanning signal to the scanning line 3a (3) is switched and supplied to the scanning line 3a (1), writing to the pixel electrode 9 corresponding to the scanning line 3a (1) is performed. In other words, the pixel electrode 9 is held at a positive potential corresponding to an image signal.

Subsequently, when displaying an image of the fourth frame, the display control circuit 104 outputs a switching signal instructing switching of the connection destination.
The common electrode 19S (1) corresponding to the scanning line 3a (1) and the common electrode 19S (3) together with the common electrode 19S (1)
) Is switched to a high potential, and then the scanning signal output circuit 102a supplies the scanning line 3a (1).
) Are sequentially output from the scanning signal to the switching circuit 102b, and the output destination is switched by the switching circuit 102b. The scanning line 3a (3), the scanning line 3a (4), the scanning line 3a (1), and the scanning line 3
a (2), scanning line 3a (7), scanning line 3a (8), scanning line 3a (5), scanning line 3a (6)
, ... are output in this order. In addition, the display control circuit 104 changes the arrangement order of the image data supplied to the data line driving circuit 101 to the pixel data to the pixels connected to the scanning line 3 a (3), the scanning line 3.
Pixel data to the pixel connected to a (4), pixel data to the pixel connected to scanning line 3a (1), pixel data to the pixel connected to scanning line 3a (2),. Sort and output.

Therefore, in the fourth frame, as shown in FIG. 11D, after the polarities of the common electrode 19S (1) and the common electrode 19S (3) are switched to a high potential, first, the scanning line 3a (1) is moved to. Is supplied to the scanning line 3a (3), writing to the pixel electrode 9 corresponding to the scanning line 3a (3) is performed, and the pixel electrode 9 is held at a negative potential corresponding to the image signal. .
Subsequently, after the polarities of the common electrode 19S (2) and the common electrode 19S (4) are switched to a low potential, the scanning signal to the scanning line 3a (2) is supplied to the scanning line 3a (4) and operates in the same manner. In this case, writing with a positive polarity is performed, and then a scanning signal to the scanning line 3a (3) is transmitted to the scanning line 3
When supplied to a (1), writing to the pixel electrode 9 connected to the scanning line 3a (1) is performed, and the negative potential corresponding to the image signal is held.
Thereafter, the same processing is performed.

Here, the common electrodes 19S (1) and 19S (3) are connected to one common electrode main line 19M (1).
When the potential is switched between a high potential and a low potential at the same timing, the scanning line 3a (1) is scanned from the time when the potentials of the common electrodes 19S (1) and 19S (3) are switched.
Difference between the time required to drive the scan line 3a and the time required to drive the scanning line 3a (3) (
ΔT in FIG. 11 occurs.
For this reason, the potential of the common electrode 19 changes due to leakage current or the like in the substrate on which the common electrode 19 is formed, and the effective value changes, resulting in a difference in the amount of pixel charge. Therefore, the potential between the pixel electrode and the common electrode changes. Therefore, even when the same potential is applied to the pixel electrode 9, there is a possibility that a luminance difference occurs between the display lines.

However, as described above, the scanning lines 3a (1) and 3a (3) drive the scanning lines 3a in the first frame, the second frame, the third frame, and the fourth frame. The order has been changed. Therefore, in the first frame, the scanning line 3a (3
), The scanning line 3a (3) is driven first and the scanning line Vg (1) is driven later in the third frame. From that
The apparent brightness between the dot area connected to the scanning line 3a (1) and the dot area connected to the scanning line 3a (3) is averaged between the first frame and the third frame. In other words, it is possible to avoid a luminance difference between display lines between frames due to a change in the effective value of the common electrode 19S.

Therefore, even when a plurality of common electrodes 19S are driven at the same time, it can be realized without causing a difference in brightness between display lines, and an image can be displayed accurately while miniaturizing the driver IC chip. It can be carried out.
In particular, when an amorphous TFT is used, it is difficult to form a driver circuit integrally with a glass substrate. Therefore, as shown in FIG. 12, the common electrode 19 is arranged along the scanning line 3a by panel wiring. It is necessary to provide the driver IC with an output terminal for outputting a control signal for controlling the potential of the common electrode 19. That is, as the number of common electrodes 19S increases, the number of output terminals also increases, leading to an increase in the size of the driver IC. However, as described above, since the number of output terminals can be reduced by half with respect to the number of common electrodes 19S, the chip size can be reduced.

In the embodiment described above, the case where the two common electrodes 19S are collectively controlled has been described. However, the present invention is not limited to this. For example, it is possible to control the three common electrodes 19S together. In this case, as shown in FIG. 13, the common electrodes 19S corresponding to the first line, the third line, and the fifth line to be written with the same polarity are combined into one, and the second line, The common electrodes 19S corresponding to the fourth and sixth lines are combined into one, before the scanning signal for the first scanning line is output, before the scanning signal for the second scanning line is output, 7 Before the scanning signal for the scanning line of the second line is output, the polarity of the common electrode corresponding to each is switched at the timing, and the scanning line 3a is driven in the normal order for the first and second frames. The third frame and the fourth frame may be driven by switching the first line and the fifth line. As a result, the apparent brightness is averaged between the first line where the variation in the effective value of the common electrode 19S is small and the fifth line where the variation in the effective value is large, which is caused by the variation in the effective value. The influence on the display image can be avoided.

It is also possible to combine four or more common electrodes 19S into one by the same procedure,
In this case, the driving order of the scanning lines 3a may be changed so that the brightness of the pixels corresponding to the common electrode 19S combined into one is averaged.
Further, it is not always necessary to combine adjacent common electrodes 19S, and any common electrode 19S may be combined as long as the common electrode 19S performs writing with the same polarity.

In the above embodiment, scanning lines are written between frames in which writing of the same polarity is performed on the same common electrode 19S, that is, between the first frame, the third frame, the second frame, and the fourth frame. The case where the driving order of 3a is switched to average the brightness has been described. However, the present invention is not necessarily limited to this, and it may be performed between frames in which the same polarity is written to the same common electrode 19S. For example, averaging may be performed between any frames. For example, averaging may be performed between the first frame and the fifth frame.

Moreover, although the case where the writing polarity of pixel data is reversed for each line has been described,
However, the present invention is not limited to this, and a method of inverting the write polarity for each of a plurality of lines may be used. In short, any method can be applied as long as the common electrode 19S having a binary value is individually controlled. be able to.
In addition, the liquid crystal display device 100 adopting the IPS method has been described, but FFS (Frnge
It can be applied even to a liquid crystal display device adopting Field Switching)
The present invention can be applied even when only the transmissive display region T is provided.

Next, an electronic apparatus to which the above-described liquid crystal display device 100 is applied will be described.
FIG. 14 is a perspective view showing a configuration of a mobile phone 120 to which the liquid crystal display device 100 is applied.
As shown in FIG. 14, the cellular phone 120 includes the display unit 100 a described above together with the earpiece 122 and the mouthpiece 123 in addition to the plurality of operation buttons 121. In the liquid crystal display device 100, components other than the display unit 100a are built in the telephone, so that they do not appear as appearance.

Further, as an electronic device to which the liquid crystal display device 100 is applied, in addition to the mobile phone shown in FIG. 14, a digital still camera, a notebook computer, a liquid crystal television, a viewfinder type (or monitor direct view type) video recorder. , A car navigation device, a pager, an electronic notebook, a calculator, a word processor, a workstation, a video phone, a POS terminal, a device equipped with a touch panel, and the like. And it cannot be overemphasized that the liquid crystal display device 100 mentioned above is applicable as a display apparatus of these various electronic devices.

It is a schematic block diagram of the liquid crystal display device which shows an example of embodiment of this invention. It is an equivalent circuit of the display part of FIG. It is a plane block diagram of a dot area. FIG. 4 is a cross-sectional view taken along line A-A ′ of FIG. 3. It is operation | movement explanatory drawing of a liquid crystal display device. It is operation | movement explanatory drawing of a liquid crystal display device. It is operation | movement explanatory drawing of a liquid crystal display device. It is explanatory drawing for demonstrating the connection relation of a common electrode and a common electrode main line. It is a signal waveform diagram for demonstrating operation | movement of a liquid crystal display device. It is a block diagram showing an example of a scanning line driving circuit. It is a signal waveform diagram with which it uses for operation | movement description of this invention. It is explanatory drawing for demonstrating the arrangement | positioning state of the conventional common electrode. It is explanatory drawing for demonstrating the other connection relation of a common electrode and a common electrode main line. It is a perspective view which shows the structure of the mobile telephone to which the liquid crystal display device of this invention is applied.

Explanation of symbols

3a scanning line, 6a data line, 9 pixel electrode, 19S common electrode, 19M common electrode main line, 100 liquid crystal display device, 101 data line driving circuit, 102 scanning line driving circuit, 1
03 common electrode drive circuit, 104 display control circuit

Claims (6)

A pixel electrode provided corresponding to each intersection of the plurality of scanning lines and the plurality of data lines;
A liquid crystal display device having a common electrode formed on the same substrate as the pixel electrode and disposed along each scanning line, and displaying an image according to a voltage between the pixel electrode and the common electrode In
A common electrode driving circuit for periodically switching and applying a binary predetermined voltage to the common electrode;
The plurality of common electrodes is a set having the same applied voltage, one end of the plurality of common electrodes belonging to the set is connected to a common common electrode main line, and the other end of the common electrode main line is the common electrode A liquid crystal display device connected to an output terminal of a drive circuit. 2. The liquid crystal display device according to claim 1, wherein among the common electrodes to which the same voltage is applied, a plurality of adjacent common electrodes are connected to the common electrode main line. A scanning line driving circuit for applying a scanning signal for selectively driving the plurality of scanning lines;
A data line driving circuit for supplying a data signal to the data line in the order according to the scanning signal;
With
The scanning line driving circuit, for a plurality of scanning lines corresponding to the common electrode belonging to the set,
Supplying the scanning signals in a different order for each frame;
The common electrode drive circuit applies a scan signal to a scan line to be driven first among a plurality of scan lines corresponding to the set to the common electrode before switching from the non-selected state to the selected state. 3. The liquid crystal display device according to claim 1, wherein the voltage is switched. The voltage applied to the common electrode is switched every frame,
4. The liquid crystal display device according to claim 3, wherein the scanning line driving circuit varies the driving order of the plurality of scanning lines corresponding to the set in the one frame period. The pixel electrode is connected to the corresponding data line via a switch element, and when the switch element is turned on by the scanning signal, a data signal supplied to the data line is applied to the pixel electrode. The liquid crystal display device according to claim 1, wherein the switch element is made of amorphous silicon. An electronic apparatus comprising the liquid crystal display device according to claim 1.

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