JP2008076733A - Electro-optical device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optical device and electronic equipment that can reduce the power consumption. <P>SOLUTION: The electro-optical device 1 includes a scanning line drive circuit 10, a data line drive circuit 20, and a capacitance line drive circuit 30. This electro-optical device 1 supplies a selection voltage to a scanning line Y by the scanning line drive circuit 10 and also supplies an image signal to a data line X by the data line drive circuit 20, after supplying one of a voltage VCOMH and a voltage VCOML to a capacitance line Z by the capacitance line drive circuit 30. Further, the electro-optical device supplies the other of the voltage VCOMH or voltage VCOML to the capacitance line Z by the capacitance line drive circuit 30, after stopping supplying the selection voltage to the scanning line Y by the scanning line drive circuit 10. Here, either the voltage VCOMH or voltage VCOML has the same potential as the voltage of a common electrode 56. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electro-optical device and an electronic apparatus.

  Conventionally, electro-optical devices such as liquid crystal devices are known. The electro-optical device includes, for example, a liquid crystal panel and a backlight disposed to face the liquid crystal panel.

  The liquid crystal panel includes a pair of substrates and a liquid crystal sandwiched between the pair of substrates.

  The liquid crystal panel includes a plurality of scanning lines and a plurality of capacitance lines alternately provided at predetermined intervals, and a plurality of scanning lines and a plurality of capacitance lines which intersect with the plurality of scanning lines and the plurality of capacitance lines and are provided at predetermined intervals. Data lines are provided.

Pixels are provided at intersections between the scanning lines and the data lines. The pixel includes a pixel capacitor composed of a pixel electrode and a common electrode, a thin film transistor (hereinafter referred to as TFT (Thin Film Transistor)), and a storage capacitor in which one electrode is connected to a capacitor line and the other electrode is connected to the pixel electrode. And comprising. A plurality of pixels are arranged in a matrix to form a display area.
A scanning line is connected to the gate of the TFT, a data line is connected to the source of the TFT, and a pixel electrode and the other electrode of the storage capacitor are connected to the drain of the TFT.

  The liquid crystal panel includes a scanning line driving circuit connected to the plurality of scanning lines, a data line driving circuit connected to the plurality of data lines, and a capacitance line driving circuit connected to the plurality of capacitance lines. , Is provided.

  The scanning line driving circuit sequentially supplies a selection voltage for selecting the scanning line to the plurality of scanning lines. For example, when a selection voltage is supplied to a certain scanning line, all TFTs connected to the scanning line are turned on, and all pixels related to the scanning line are selected.

When the scanning line is selected, the data line driving circuit supplies an image signal to the plurality of data lines, and writes an image voltage based on the image signal to the pixel electrode through the TFT in the on state.
Here, the data line driving circuit supplies an image signal having a voltage (hereinafter referred to as positive polarity) having a potential higher than that of the common electrode to the data line, and an image voltage based on the positive polarity image signal is supplied to the pixel. Positive polarity writing to be written to the electrodes, and an image signal having a voltage lower than the common electrode voltage (hereinafter referred to as negative polarity) is supplied to the data line, and the image voltage based on the negative polarity image signal is supplied to the pixel. Negative polarity writing to be written to the electrodes is alternately performed every predetermined period.

  The capacitor line driving circuit supplies a predetermined voltage to each capacitor line.

The above electro-optical device operates as follows.
That is, by sequentially supplying the selection voltage to the scanning line, all the TFTs connected to the certain scanning line are turned on, and all the pixels related to the scanning line are selected. Then, an image signal is supplied to the data line in synchronization with the selection of these pixels. Then, an image signal is supplied to all the selected pixels via the on-state TFTs, and an image voltage based on the image signal is written to the pixel electrode.

When an image voltage is written to the pixel electrode, a driving voltage is applied to the liquid crystal due to a potential difference between the pixel electrode and the common electrode. When a driving voltage is applied to the liquid crystal, the alignment and order of the liquid crystal change, and light from the backlight that transmits the liquid crystal changes, so that gradation display is performed.
Note that the driving voltage applied to the liquid crystal is held by a storage capacitor for a period that is three orders of magnitude longer than the period during which the image voltage is written.

  By the way, the electro-optical device as described above is used in, for example, a portable device. In portable devices, reduction of power consumption has recently been demanded. Thus, an electro-optical device has been proposed that can reduce power consumption by changing the voltage of the capacitor line after writing the image voltage to the pixel electrode (see, for example, Patent Document 1).

  An operation of the electro-optical device according to the conventional example in which the voltage of the capacitor line is changed as in Patent Document 1 will be described with reference to FIG.

FIG. 15 is a timing chart of the electro-optical device according to the conventional example.
In FIG. 15, LCCOM indicates the voltage of the common electrode, and VST indicates the voltage of the capacitor line. Further, γ1 represents the voltage of the pixel electrode when positive writing is performed, and γ1A represents the voltage of the pixel electrode when the voltage of the capacitor line is increased after performing positive writing. Further, γ2 indicates the voltage of the pixel electrode when negative polarity writing is performed, and γ2A indicates the voltage of the pixel electrode when the voltage of the capacitor line is decreased after performing negative polarity writing.
Here, the liquid crystal included in the electro-optical device according to the conventional example is assumed to operate in a normally black mode.

  First, with reference to the period from time t50 to t54, the operation at the time of positive writing of the electro-optical device according to the conventional example will be described.

  At time t50, the capacitor line driving circuit supplies a predetermined voltage to the capacitor line, and the voltage VST of the capacitor line is set to the voltage V7.

  At time t51, the scanning line driving circuit supplies a selection voltage to the scanning line, and the data line driving circuit supplies a positive image signal to the data line, so that the image voltage based on the positive image signal is supplied to the pixel. Write to the electrode. Then, if the positive image signal supplied to the data line is, for example, an image signal corresponding to a black gradation, the voltage γ1 of the pixel electrode becomes the voltage V8. Also, if the positive image signal supplied to the data line is an image signal corresponding to, for example, white gradation, the voltage γ1 of the pixel electrode becomes the voltage V11.

At time t52, the capacitor line driving circuit supplies a predetermined voltage to the capacitor line, and raises the voltage VST of the capacitor line from the voltage V7 to the voltage V9. Then, the charge corresponding to the increased voltage of the capacitor line is distributed between the storage capacitor and the pixel capacitor. For this reason, the voltage γ1 of the pixel electrode rises and becomes γ1A at time t53.
Therefore, a driving voltage corresponding to the potential difference between the common electrode voltage LCCOM and the pixel electrode voltage γ1A is applied to the liquid crystal.

  In other words, in the electro-optical device according to the conventional example, at the time of positive polarity writing, the image voltage based on the positive polarity image signal is written to the pixel electrode, and then the voltage of the capacitor line is increased. Then, when an image voltage based on a positive polarity image signal is written to the pixel electrode, the voltage of the pixel electrode is γ1, but when the voltage of the capacitor line is increased, the voltage of the pixel electrode increases to γ1A. That is, by increasing the voltage of the capacitor line, the potential difference between the voltage LCCOM of the common electrode and the voltage of the pixel electrode increases.

  Next, with reference to the period from time t54 to t58, the operation at the time of negative polarity writing of the electro-optical device according to the conventional example will be described.

  At time t54, the capacitor line driving circuit supplies a predetermined voltage to the capacitor line, and the voltage VST of the capacitor line is set to the voltage V6.

  At time t55, the scanning line driving circuit supplies a selection voltage to the scanning line, and the data line driving circuit supplies a negative image signal to the data line so that an image voltage based on the negative image signal is supplied to the pixel. Write to the electrode. Then, if the negative image signal supplied to the data line is, for example, an image signal corresponding to a black gradation, the voltage γ2 of the pixel electrode becomes the voltage V5. If the negative image signal supplied to the data line is an image signal corresponding to, for example, white gradation, the voltage γ2 of the pixel electrode becomes the voltage V2.

At time t56, the capacitor line driving circuit supplies a predetermined voltage to the capacitor line, and the voltage VST of the capacitor line is decreased from the voltage V6 to the voltage V4. Then, the charge corresponding to the reduced voltage of the capacitor line is distributed between the storage capacitor and the pixel capacitor. Therefore, the voltage γ2 of the pixel electrode decreases and becomes γ2A at time t57.
Therefore, a driving voltage corresponding to the potential difference between the common electrode voltage LCCOM and the pixel electrode voltage γ2A is applied to the liquid crystal.

  That is, in the electro-optical device according to the conventional example, the voltage of the capacitor line is lowered after writing the image voltage based on the negative image signal to the pixel electrode during the negative polarity writing. Then, when the image voltage based on the negative image signal is written to the pixel electrode, the voltage of the pixel electrode is γ2, but when the voltage of the capacitor line is decreased, the voltage of the pixel electrode is decreased to γ2A. That is, by reducing the voltage of the capacitor line, the potential difference between the voltage LCCOM of the common electrode and the voltage of the pixel electrode is increased.

As described above, in the electro-optical device according to the conventional example, the voltage of the common electrode and the pixel are changed even if the amplitude of the image voltage is reduced by changing the voltage of the capacitor line after the image voltage is written to the pixel electrode. The potential difference from the electrode voltage can be increased. Therefore, it is possible to reduce power consumption by reducing the amplitude of the image voltage while securing the amplitude of the driving voltage applied to the liquid crystal and suppressing the deterioration of display quality.
JP 2002-196358 A

Incidentally, as shown in FIG. 15, in the electro-optical device according to the above-described conventional example, at the time of positive writing, a positive image signal is supplied to the data line by the data line driving circuit, and the voltage of the pixel electrode is increased. The voltage is varied between V8 and V11. Further, at the time of negative writing, a negative image signal is supplied to the data line by the data line driving circuit, and the voltage of the pixel electrode is changed between voltages V2 to V5. Therefore, the data line driving circuit must supply the image signal to the data line so that the voltage of the pixel electrode can be changed between the voltages V2 to V11. Therefore, if the potential difference between the voltage V2 and the voltage V11 is large, the voltage amplitude of the image signal supplied to the data line by the data line driving circuit must be increased. However, if the voltage amplitude of the image signal is increased, the data line driving circuit may not operate normally due to the large voltage of the image signal supplied to the data line. For this reason, the data line driving circuit has to be manufactured by a high breakdown voltage process.
However, since the data line driving circuit manufactured by the high withstand voltage process requires a high driving voltage when operating, the power consumption may increase.

  SUMMARY An advantage of some aspects of the invention is that it provides an electro-optical device and an electronic apparatus that can reduce power consumption.

  The electro-optical device of the present invention includes a plurality of scanning lines, a plurality of data lines, a plurality of capacitance lines, and a plurality of pixel electrodes provided corresponding to intersections of the plurality of scanning lines and the plurality of data lines. An electro-optical device comprising: a pixel capacitor having a common electrode facing the pixel electrode; and a storage capacitor having one electrode connected to the capacitor line and the other electrode connected to the pixel electrode. A first voltage and a second voltage having a potential lower than the first voltage are alternately selected, and the capacitance line driving circuit for sequentially supplying the selected voltage to the plurality of capacitance lines, and the scanning A scanning line driving circuit for sequentially supplying a selection voltage for selecting a line to the plurality of scanning lines; and a data line driving circuit for supplying an image signal to the plurality of data lines when the scanning line is selected. Comprising the first voltage or the second voltage One of the voltages is set to the same potential as the voltage of the common electrode, and after either one of the first voltage or the second voltage is supplied to the capacitor line by the capacitor line driver circuit, the scanning line driver circuit The selection voltage is supplied to the scanning line, the image signal is supplied to the data line by the data line driving circuit, and the supply of the selection voltage to the scanning line is stopped by the scanning line driving circuit. Thereafter, the capacitor line driving circuit supplies the other one of the first voltage and the second voltage to the capacitor line.

  According to the present invention, either the first voltage or the second voltage supplied to the capacitor line by the capacitor line driving circuit is set to the same potential as the voltage of the common electrode. For this reason, compared with the case where the potentials of the first voltage, the second voltage, and the common electrode are different from each other, one power supply line for supplying each voltage can be reduced, and the electro-optical device can be downsized.

Further, according to the present invention, if the voltage of the image signal supplied from the data line driving circuit is set higher than the voltage of the common electrode, positive writing can be performed, and the potential lower than the voltage of the common electrode. Thus, negative polarity writing can be performed.
Further, for example, after the first voltage is supplied to the capacitor line by the capacitor line driving circuit, the positive writing is performed as described above, and then the second voltage is supplied to the capacitor line by the capacitor line driving circuit. Decreases from the first voltage to the second voltage. Then, the charge corresponding to the voltage of the capacitor line that has decreased from the first voltage to the second voltage is distributed between the storage capacitor and the pixel capacitor, and the voltage of the pixel electrode included in the pixel capacitor decreases. Accordingly, by reducing the voltage of the capacitor line from the first voltage to the second voltage and making the voltage of the pixel electrode lower than the voltage of the common electrode, an image voltage having a lower potential than the voltage of the common electrode is applied to the pixel electrode. Negative writing can be performed in a pseudo manner.
In addition, for example, after the second voltage is supplied to the capacitor line by the capacitor line driving circuit, the negative polarity writing is performed as described above, and then the first voltage is supplied to the capacitor line by the capacitor line driving circuit. Increases from the second voltage to the first voltage. Then, the charge corresponding to the voltage of the capacitor line that has increased from the second voltage to the first voltage is distributed between the storage capacitor and the pixel capacitor, and the voltage of the pixel electrode included in the pixel capacitor increases. Therefore, by raising the voltage of the capacitor line from the second voltage to the first voltage and making the voltage of the pixel electrode higher than the voltage of the common electrode, an image voltage having a higher potential than the voltage of the common electrode is applied to the pixel electrode. The positive polarity writing can be performed in a pseudo manner.
As described above, when performing positive polarity writing or performing pseudo negative polarity writing after performing positive polarity writing, the data line driving circuit supplies a positive polarity image signal to the data line. On the other hand, when performing negative polarity writing or performing pseudo positive polarity writing after performing negative polarity writing, a negative polarity image signal is supplied to the data line by the data line driving circuit. Therefore, in any of the above cases, when positive polarity writing is performed as in the above-described conventional example, the voltage of the image signal is set higher than the voltage of the common electrode, and negative polarity writing is performed. In this case, the voltage amplitude of the image signal can be made smaller than when the voltage of the image signal is made lower than the voltage of the common electrode. Therefore, the data line driving circuit can be operated normally without being manufactured by a high withstand voltage process, so that the driving voltage supplied to the data line driving circuit can be lowered and the power consumption can be reduced.

  In the electro-optical device according to the aspect of the invention, when the second voltage is the same potential as the voltage of the common electrode, the voltage level of the image signal is lower than the voltage level of the first voltage and the voltage level of the common electrode. It is preferable to set higher.

  According to the present invention, the second voltage is set to the same potential as the voltage of the common electrode, and the voltage level of the image signal is lower than the voltage level of the first voltage and higher than the voltage level of the common electrode. For this reason, it is possible to perform positive polarity writing using a positive polarity image signal whose potential is higher than the voltage of the common electrode, or to perform negative polarity writing after performing positive polarity writing. Therefore, there is an effect similar to the effect described above.

  In the electro-optical device according to the aspect of the invention, it is preferable that when the first voltage has the same potential as the voltage of the common electrode, the voltage level of the image signal is set higher than the voltage level of the first voltage.

  According to this invention, the first voltage is set to the same potential as the voltage of the common electrode, and the voltage level of the image signal is set higher than the voltage level of the first voltage. For this reason, it is possible to perform positive polarity writing using a positive polarity image signal whose potential is higher than the voltage of the common electrode, or to perform negative polarity writing after performing positive polarity writing. Therefore, there is an effect similar to the effect described above.

  In the electro-optical device according to the aspect of the invention, it is preferable that the voltage level of the image signal is set lower than the voltage level of the second voltage when the second voltage is the same potential as the voltage of the common electrode.

  According to this invention, the second voltage is set to the same potential as the voltage of the common electrode, and the voltage level of the image signal is set lower than the voltage level of the second voltage. For this reason, it is possible to perform negative polarity writing using a negative polarity image signal whose potential is lower than the voltage of the common electrode, or to perform positive polarity writing after performing negative polarity writing. Therefore, there is an effect similar to the effect described above.

  In the electro-optical device according to the aspect of the invention, when the first voltage is the same potential as the voltage of the common electrode, the voltage level of the image signal is higher than the voltage level of the second voltage and the voltage level of the common electrode. Is preferably set lower.

  According to the present invention, the first voltage is set to the same potential as the voltage of the common electrode, and the voltage level of the image signal is higher than the voltage level of the second voltage and lower than the voltage level of the common electrode. For this reason, it is possible to perform negative polarity writing using a negative polarity image signal whose potential is lower than the voltage of the common electrode, or to perform positive polarity writing after performing negative polarity writing. Therefore, there is an effect similar to the effect described above.

  In the electro-optical device according to the aspect of the invention, it is preferable that after the supply of the selection voltage to the scanning line is stopped by the scanning line driving circuit, the capacitive line is brought into a floating state by the capacitive line driving circuit.

  According to the present invention, after the supply of the selection voltage to the scanning line is stopped by the scanning line driving circuit, the capacitor line is brought into a floating state. That is, after the image voltage was written to the pixel electrode and the voltage of the pixel electrode relative to the voltage of the common electrode was stabilized, the capacitor line was brought into a floating state. Accordingly, the period during which the voltage is supplied from the capacitor line driver circuit to the capacitor line is shortened, so that power consumption can be reduced.

  In the electro-optical device according to the aspect of the invention, after the supply of the selection voltage is stopped, the capacitor line driving circuit supplies the other one of the first voltage and the second voltage to the capacitor line, and then the capacitor line. Is preferably in a floating state.

  According to the present invention, after the supply of the selection voltage is stopped, either one of the first voltage and the second voltage is supplied to the capacitor line by the capacitor line driving circuit, and then the capacitor line is brought into a floating state. That is, after writing the image voltage to the pixel electrode and stabilizing the voltage of the pixel electrode with respect to the voltage of the common electrode, the voltage of the capacitor line is lowered from the first voltage to the second voltage and pseudo negative writing is performed. Alternatively, the positive voltage writing is performed by raising the voltage of the capacitor line from the second voltage to the first voltage, and then the capacitor line is set in a floating state. Therefore, there is an effect similar to the effect described above.

An electronic apparatus according to an aspect of the invention includes the above-described electro-optical device.
According to the present invention, there are effects similar to those described above.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of embodiments and modifications, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.

<First Embodiment>
FIG. 1 is a block diagram of an electro-optical device 1 according to the first embodiment of the present invention.
The electro-optical device 1 includes a liquid crystal panel AA and a backlight 90 that is disposed to face the liquid crystal panel AA and emits light. The electro-optical device 1 performs transmissive display using light from the backlight 90.

  The liquid crystal panel AA includes a display screen A in which a plurality of pixels 50 are arranged in a matrix to display an image, a scanning line driving circuit 10 that is provided around the display screen A and drives the pixels 50, and a data line driving circuit. 20 and a capacitor line driving circuit 30.

  The backlight 90 emits light. The backlight 90 is provided on the back surface of the liquid crystal panel AA. For example, a cold cathode fluorescent tube (CCFL (Cold Cathode Fluorescent Lamp)), a light emitting diode (LED (Light Emitting Diode)), or electroluminescence (EL (Electro Luminescence)). )).

Hereinafter, the configuration of the liquid crystal panel AA will be described in detail.
The liquid crystal panel AA intersects 320 scanning lines Y1 to Y320 and 320 capacitive lines Z1 to Z320 alternately provided at predetermined intervals, the scanning lines Y1 to Y320, and the capacitive lines Z1 to Z320, and , 240 columns of data lines X1 to X240 provided at predetermined intervals.

  Pixels 50 are provided at the intersections of the scanning lines Y and the data lines X. The pixel 50 includes a TFT 51, a pixel capacitor 54 having a pixel electrode 55 and a common electrode 56, and a storage capacitor 53 in which one electrode is connected to the capacitor line Z and the other electrode is connected to the pixel electrode 55.

  The scanning line Y is connected to the gate of the TFT 51, the data line X is connected to the source of the TFT 51, and the other electrode of the pixel electrode 55 and the storage capacitor 53 is connected to the drain of the TFT 51. Therefore, the TFT 51 is turned on when a selection voltage is applied from the scanning line Y, and the data line X and the pixel electrode 55 and the other electrode of the storage capacitor 53 are brought into conduction.

  The capacitor line driving circuit 30 alternately selects the voltage VCOMH as the first voltage and the voltage VCOML as the second voltage having a lower potential than the voltage VCOMH, and sequentially selects the selected voltages to the capacitor lines Z1 to Z320. Supply. For example, when the voltage VCOML is supplied to a certain capacitance line Z, the voltage of one electrode of all the storage capacitors 53 connected to this capacitance line Z becomes the voltage VCOML.

  The scanning line driving circuit 10 sequentially supplies a selection voltage for selecting each scanning line Y to the scanning lines Y1 to Y320. For example, when a selection voltage is supplied to a certain scanning line Y, all the TFTs 51 connected to the scanning line Y are turned on, and all the pixels 50 related to the scanning line Y are selected.

The data line driving circuit 20 supplies an image signal to the data lines X1 to X240, and writes an image voltage based on the image signal to the pixel electrode 55 via the TFT 51 in the on state.
Here, the data line driving circuit 20 supplies a positive image signal having a higher potential than the voltage of the common electrode 56 to the data line X, and writes an image voltage based on the positive image signal to the pixel electrode 55. Perform positive polarity writing.

The above electro-optical device 1 operates as follows.
That is, first, the voltage VCOMH is supplied from the capacitive line driving circuit 30 to the capacitive line Zm in the m-th row (m is an integer satisfying 1 ≦ m ≦ 320).

  Next, by supplying a selection voltage from the scanning line driving circuit 10 to the scanning line Ym, all the TFTs 51 connected to the scanning line Ym are turned on, and all the pixels 50 related to the scanning line Ym are selected.

  Further, in synchronization with the selection of the pixel 50 related to the scanning line Ym, a positive image signal is supplied from the data line driving circuit 20 to the data lines X1 to X240.

  Then, a positive-polarity image signal is supplied from the data line driving circuit 20 to the pixels 50 related to the scanning line Ym selected by the scanning line driving circuit 10 via the data lines X1 to X240 and the on-state TFT 51. An image voltage based on the positive polarity image signal is written to the pixel electrode 55.

  Next, the voltage VCOML or the voltage VCOMH is supplied from the capacitor line driving circuit 30 to the capacitor line Zm according to the voltage of the capacitor line Z (m−1) in the (m−1) th row. Specifically, when the voltage of the capacitor line Z (m−1) is the voltage VCOML, the voltage VCOMH is supplied from the capacitor line driving circuit 30 to the capacitor line Zm. On the other hand, when the voltage of the capacitance line Z (m−1) is the voltage VCOMH, the voltage VCOML is supplied from the capacitance line driving circuit 30 to the capacitance line Zm.

When the voltage VCOMH is supplied from the capacitor line driving circuit 30 to the capacitor line Zm, the voltage of the capacitor line Zm does not change, so the voltage of the pixel electrode 55 does not change.
On the other hand, when the voltage VCOML is supplied from the capacitive line driving circuit 30 to the capacitive line Zm, the voltage of the capacitive line Zm decreases. Then, the electric charge corresponding to the voltage decreased from the voltage VCOMH to the voltage VCOML of the capacitor line Zm is distributed between the storage capacitor 53 and the pixel capacitor 54. For this reason, the voltage of the pixel electrode 55 decreases.

Thus, a potential difference is generated between the pixel electrode 55 and the common electrode 56, and a driving voltage is applied to the liquid crystal.
When a driving voltage is applied to the liquid crystal, the alignment and order of the liquid crystal change, and the light from the backlight 90 that transmits the liquid crystal changes. A gradation display is performed by the changed light.
Note that the drive voltage applied to the liquid crystal is held by the storage capacitor 53 for a period that is three digits longer than the period during which the image voltage is written.

FIG. 2 is a block diagram of the capacitor line driving circuit 30.
The capacitor line drive circuit 30 includes a first unit capacitor line drive circuit 31 provided corresponding to the odd-numbered capacitor lines Z and a second unit capacitor line provided corresponding to the even-numbered capacitor lines Z. Drive circuit 32.
The scanning lines Y1 to Y320, the output terminal of the control circuit (not shown), and the output terminal of the power supply circuit (not shown) are connected to the input terminal of the capacitive line driving circuit 30, and the output terminal of the capacitive line driving circuit 30 is connected to the output terminal. The capacitor lines Z1 to Z320 are connected.
A selection voltage is sequentially input from the scanning lines Y1 to Y320 to the capacitance line driving circuit 30, and a clock signal SCCL and a polarity instruction signal SCPOL are input from a control circuit (not shown), and a voltage VCOML and a voltage VCOML are supplied from a power supply circuit (not shown). The voltage VCOMH is input. Here, the clock signal SCCL is a signal that alternately becomes H level or L level every half period of one horizontal scanning period (hereinafter referred to as ½ horizontal scanning period), and the polarity instruction signal SCPOL is 1 The signal alternately becomes H level or L level every frame period.

FIG. 3 is a block diagram of the first unit capacitance line driving circuit 31.
The first unit capacitor line drive circuit 31 includes a control signal generation circuit 301 and a voltage selection circuit 302.

The corresponding scanning line Y and the output terminal of the control circuit (not shown) are connected to the input terminal of the control signal generation circuit 301, and the input terminal of the voltage selection circuit 302 is connected to the output terminal of the control signal generation circuit 301. It is connected. A selection voltage is sequentially input from the corresponding scanning line Y to the control signal generation circuit 301, and a clock signal SCCL and a polarity instruction signal SCPOL are input from the control circuit.
The control signal generation circuit 301 takes in the polarity instruction signal SCPOL in synchronization with the selection voltage and the clock signal SCCL and outputs it as the control signal CTRL.

The input terminal of the voltage selection circuit 302 is connected to the output terminal of the control signal generation circuit 301 and the output terminal of the power supply circuit (not shown), and the corresponding capacitance line Z is connected to the output terminal of the voltage selection circuit 302. Has been. The voltage selection circuit 302 receives the control signal CTRL from the control signal generation circuit 301 and receives the voltage VCOML and the voltage VCOMH from the power supply circuit.
The voltage selection circuit 302 selects either the voltage VCOML or the voltage VCOMH according to the control signal CTRL and outputs the selected voltage.
The voltage selection circuit 302 outputs the voltage VCOMH at a predetermined timing.

FIG. 4 is a block diagram of the second unit capacitance line driving circuit 32.
The second unit capacitor line drive circuit 32 includes an inverter 303 in addition to the control signal generation circuit 301 and the voltage selection circuit 302 described above.

The output terminal of the voltage selection circuit 302 is connected to the input terminal of the inverter 303, and the corresponding capacitance line Z is connected to the output terminal of the inverter 303.
The inverter 303 inverts the polarity of the voltage output from the voltage selection circuit 302 and outputs it. Specifically, the inverter 303 outputs the voltage VCOMH when the voltage selection circuit 302 outputs the voltage VCOML, and outputs the voltage VCOML when the voltage selection circuit 302 outputs the voltage VCOMH. .

FIG. 5 is a timing chart of the capacitor line driving circuit 30.
First, focusing on the capacitance line Z1, the operation of the capacitance line drive circuit 30 will be described.

  At time t1, the voltage selection circuit 302 supplies the voltage VCOMH to the capacitor line Z1.

  At time t2, the scanning line driving circuit 10 supplies the selection voltage to the scanning line Y1, and the voltage of the scanning line Y1 is set to the voltage VGH.

  At time t3, the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Y1, and the voltage of the scanning line Y1 is set to the voltage VGL.

  At time t4, the control signal generation circuit 301 refers to the voltage level of the polarity instruction signal SCPOL in synchronization with the clock signal SCCL becoming H level. At time t4, since the polarity instruction signal SCPOL is at the H level, the control signal CTRL at the H level is output. Therefore, based on the H level control signal CTRL output from the control signal generation circuit 301, the voltage selection circuit 302 supplies the voltage VCOMH to the capacitor line Z1.

  At time t5, the voltage selection circuit 302 supplies the voltage VCOMH to the capacitor line Z1.

  At time t6, the scanning line driving circuit 10 supplies the selection voltage to the scanning line Y1, and the voltage of the scanning line Y1 is set to the voltage VGH.

  At time t7, the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Y1, and the voltage of the scanning line Y1 is set to the voltage VGL.

  At time t8, the control signal generation circuit 301 refers to the voltage level of the polarity instruction signal SCPOL in synchronization with the clock signal SCCL becoming H level. At time t8, the polarity instruction signal SCPOL is at the L level, so the control signal CTRL at the L level is output. Therefore, the voltage selection circuit 302 supplies the voltage VCOML to the capacitor line Z1 based on the L-level control signal CTRL output from the control signal generation circuit 301.

As described above, the voltage VCOMH is supplied to the capacitor line Z1 by the voltage selection circuit 302 before the half horizontal scanning period before the time when the scanning line driving circuit 10 supplies the selection voltage to the scanning line Y1.
If the polarity instruction signal SCPOL is at H level after a half horizontal scanning period after the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Y1, the control signal generation circuit 301 When the level control signal CTRL is output and the polarity instruction signal SCPOL is at the L level, the control signal generation circuit 301 outputs the L level control signal CTRL. When the control signal generation circuit 301 outputs an H level control signal CTRL, the voltage selection circuit 302 supplies the voltage VCOMH to the capacitor line Z1. On the other hand, when the control signal generation circuit 301 outputs an L level control signal CTRL, the voltage selection circuit 302 supplies the voltage VCOML to the capacitor line Z1.

  Next, the operation of the capacitor line driving circuit 30 will be described by paying attention to the scanning line Yp in the p-th row (p is an odd number satisfying 2 ≦ p ≦ 320).

  The control signal generation circuit 301 and the voltage selection circuit 302 related to the scanning line Yp operate in the same manner as the control signal generation circuit 301 and the voltage selection circuit 302 related to the scanning line Y1.

That is, the voltage VCOMH is supplied to the capacitor line Zp by the voltage selection circuit 302 before the half horizontal scanning period from the time when the scanning line driving circuit 10 supplies the selection voltage to the scanning line Yp.
If the polarity instruction signal SCPOL is at H level after a half horizontal scanning period after the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Yp, the control signal generation circuit 301 When the level control signal CTRL is output and the polarity instruction signal SCPOL is at the L level, the control signal generation circuit 301 outputs the L level control signal CTRL. When the control signal generation circuit 301 outputs an H level control signal CTRL, the voltage selection circuit 302 supplies the voltage VCOMH to the capacitor line Zp. On the other hand, when the control signal generation circuit 301 outputs an L level control signal CTRL, the voltage selection circuit 302 supplies the voltage VCOML to the capacitor line Zp.

  Next, the operation of the capacitor line driving circuit 30 will be described by focusing on the scanning line Yq in the q-th row (q is an even number satisfying 2 ≦ q ≦ 320).

  Compared with the voltage selection circuit 302 related to the scanning line Y1, the voltage selection circuit 302 related to the scanning line Yq outputs a half horizontal scanning period before the time when the selection voltage is supplied to the scanning line Y by the scanning line driving circuit 10. Different voltage.

That is, the voltage selection circuit 302 outputs the voltage VCOML before 1/2 horizontal scanning period from the time when the scanning line driving circuit 10 supplies the selection voltage to the scanning line Yq. The polarity of the voltage VCOML is inverted by the inverter 303, and the voltage VCOMH is supplied to the capacitor line Zq.
If the polarity instruction signal SCPOL is at H level after a half horizontal scanning period after the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Yq, the control signal generation circuit 301 When the level control signal CTRL is output and the polarity instruction signal SCPOL is at the L level, the control signal generation circuit 301 outputs the L level control signal CTRL. When the control signal generation circuit 301 outputs an H level control signal CTRL, the voltage selection circuit 302 outputs the voltage VCOMH. The polarity of the voltage VCOMH is inverted by the inverter 303, and the voltage VCOML is supplied to the capacitor line Zq. On the other hand, when the control signal generation circuit 301 outputs the L level control signal CTRL, the voltage selection circuit 302 outputs the voltage VCOML. The polarity of the voltage VCOML is inverted by the inverter 303, and the voltage VCOMH is supplied to the capacitor line Zq.

FIG. 6 is a timing chart of the electro-optical device 1.
In FIG. 6, LCCOM indicates the voltage of the common electrode 56, and VST indicates the voltage of the capacitor line Z. Further, γ1A indicates the voltage of the pixel electrode 55 when positive polarity writing is performed. Further, γ2B indicates the voltage of the pixel electrode 55 when the positive polarity writing is performed before the negative polarity writing is simulated, and γ2A is the pixel electrode when the negative polarity writing is simulated. 55 voltage is shown.

  First, the operation at the time of positive writing of the electro-optical device 1 will be described with reference to a period from time t10 to t12.

  At time t10, the capacitor line driving circuit 30 supplies the voltage VCOMH to the capacitor line Z, and the voltage VST of the capacitor line Z is set to the voltage VCOMH.

At time t11, the scanning line driving circuit 10 supplies a selection voltage to the scanning line Y, and the data line driving circuit 20 supplies a positive polarity image signal to the data line X, based on the positive polarity image signal. An image voltage is written into the pixel electrode 55. Then, if the positive image signal supplied to the data line X is an image signal corresponding to, for example, a black gradation, the voltage γ1A of the pixel electrode 55 becomes the voltage V10. If the positive image signal supplied to the data line X is an image signal corresponding to, for example, white gradation, the voltage γ1A of the pixel electrode 55 becomes the voltage V12.
Therefore, a driving voltage corresponding to the potential difference between the voltage LCCOM of the common electrode 56 and the voltage γ1A of the pixel electrode 55 is applied to the liquid crystal.

  Next, with reference to a period from time t12 to t16, an operation in the case where pseudo negative writing of the electro-optical device 1 is performed will be described.

  At time t12, the capacitor line drive circuit 30 supplies the voltage VCOMH to the capacitor line Z, and the voltage VST of the capacitor line Z is set to the voltage VCOMH.

At time t13, as in time t11, an image voltage based on a positive image signal is written to the pixel electrode 55.
Here, the liquid crystal is aligned and ordered in a case where an image voltage based on a positive image signal is written to the pixel electrode 55 and a case where an image voltage based on a negative image signal is written to the pixel electrode 55. The degree of change is different. For this reason, even if the polarity of the image signal is different, the voltage of the negative polarity image signal is set with respect to the voltage of the positive polarity image signal so that the degree of change in the alignment and order of the liquid crystal does not change. Write. That is, at time t11, the voltage of the pixel electrode is γ1A, but at time t13, the voltage of the pixel electrode is γ2B.

At time t <b> 14, the capacitor line driving circuit 30 supplies the voltage VCOML having the same potential as the voltage LCCOM of the common electrode 56 to the capacitor line Z, and decreases the voltage VST of the capacitor line Z from the voltage VCOMH to the voltage VCOML. Then, since the charge corresponding to the voltage VST of the capacitor line Z that has decreased from the voltage VCOMH to the voltage VCOML is distributed between the storage capacitor 53 and the pixel capacitor 54, the voltage γ2B of the pixel electrode 55 decreases, At time t15, γ2A is obtained.
Therefore, a driving voltage corresponding to the potential difference between the common electrode voltage LCCOM and the pixel electrode voltage γ2A is applied to the liquid crystal.

  That is, the electro-optical device 1 has the following two methods as a method of writing an image voltage based on an image signal to the pixel electrode 55.

The first method is a method of performing positive polarity writing as shown in the period from time t10 to t12 in FIG.
In this positive polarity writing method, the capacitor line drive circuit 30 supplies the voltage VCOMH to the capacitor line Z, and then the scan line drive circuit 10 supplies the selection voltage to the scan line Y and the data line drive circuit. 20, a positive-polarity image signal having a higher potential than the voltage LCCOM of the common electrode 56 is supplied to the data line X.

The second method is a method of performing negative polarity writing in a pseudo manner as shown in the period from time t12 to t16 in FIG.
In the method of performing the negative polarity writing in a pseudo manner, first, the capacitor line drive circuit 30 supplies the voltage VCOMH to the capacitor line Z, and then the scan line drive circuit 10 supplies the selection voltage to the scan line Y. The data line driving circuit 20 supplies a positive image signal having a higher potential than the voltage LCCOM of the common electrode 56 to the data line X. Next, after the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Y and the voltage γ2B of the pixel electrode 55 with respect to the voltage LCCOM of the common electrode 56 is stabilized, the capacitance line driving circuit 30 A voltage VCOML having the same potential as the voltage LCCOM of the common electrode 56 is supplied to the capacitor line Z.
That is, in the method of performing negative polarity writing in a pseudo manner, after the positive polarity writing is performed by the first method described above, the voltage VCOML having the same potential as the voltage LCCOM of the common electrode 56 is obtained by the capacitor line driving circuit 30. Is supplied to the capacitor line Z.

According to this embodiment, there are the following effects.
(1) The voltage LCCOM of the common electrode 56 and the voltage VCOML are set to the same potential. Therefore, the power supply line that supplies the voltage LCCOM of the common electrode 56 and the power supply line that supplies the voltage VCOML are made common as compared to the case where the potentials of the voltage LCCOM of the common electrode 56 and the voltage VCOML are different. Thus, one power supply line can be reduced, and the electro-optical device 1 can be downsized.

  (2) As a method of writing an image voltage based on an image signal to the pixel electrode 55, a method of performing positive polarity writing as a first method and a method of performing negative polarity writing as a second method in a pseudo manner , Provided. Here, in the case of performing the positive polarity writing and the case of performing the negative polarity writing in a pseudo manner, the image signal for writing the image voltage to the pixel electrode 55 is set to have a higher potential than the voltage LCCOM of the common electrode 56. did. Therefore, as in the above-described conventional example, when positive polarity writing is performed, the voltage of the image signal is set higher than the voltage LCCOM of the common electrode 56, and when negative polarity writing is performed, Compared with the case where the potential of the signal is lower than the voltage LCCOM of the common electrode 56, the voltage amplitude of the image signal can be reduced. Therefore, the data line driving circuit 20 can be normally operated without being manufactured by a high withstand voltage process, so that the driving voltage supplied to the data line driving circuit 20 can be lowered and the power consumption can be reduced.

<Second Embodiment>
FIG. 7 is a timing chart of the electro-optical device 1A according to the second embodiment of the invention.
This embodiment is different from the electro-optical device 1 according to the first embodiment in that the voltage LCCOM of the common electrode 56 and the voltage VCOMH are set to the same potential.

  The electro-optical device 1 </ b> A has the following two methods as a method of writing an image voltage based on an image signal into the pixel electrode 55.

The third method is a method of performing positive polarity writing as shown in the period from time t20 to t22 in FIG.
In this positive polarity writing method, the capacitor line drive circuit 30 supplies the voltage VCOMH having the same potential as the voltage LCCOM of the common electrode 56 to the capacitor line Z, and then the scan line drive circuit 10 scans the selection voltage. In addition to being supplied to the line Y, the data line driving circuit 20 supplies a positive-polarity image signal having a higher potential than the voltage LCCOM of the common electrode 56 to the data line X.

The fourth method is a method of performing negative writing in a pseudo manner as shown in the period from time t22 to t26 in FIG.
In this method of performing negative polarity writing in a pseudo manner, first, the capacitor line driving circuit 30 supplies the voltage VCOMH having the same potential as the voltage LCCOM of the common electrode 56 to the capacitor line Z, and then the scanning line driving circuit 10 In addition to supplying the selection voltage to the scanning line Y, the data line driving circuit 20 supplies a positive image signal having a higher potential than the voltage LCCOM of the common electrode 56 to the data line X. Next, after the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Y and the voltage γ2B of the pixel electrode 55 with respect to the voltage LCCOM of the common electrode 56 is stabilized, the capacitance line driving circuit 30 The voltage VCOML is supplied to the capacitor line Z.
That is, in the method of performing negative polarity writing in a pseudo manner, the voltage line VCOML is supplied to the capacitance line Z by the capacitance line drive circuit 30 after performing positive polarity writing by the third method described above.

According to this embodiment, there are the following effects.
(3) The voltage LCCOM of the common electrode 56 and the voltage VCOMH are set to the same potential. For this reason, the power supply line that supplies the voltage LCCOM of the common electrode 56 and the power supply line that supplies the voltage VCOMH are made common as compared with the case where the potentials of the voltage LCCOM of the common electrode 56 and the voltage VCOMH are different. As a result, one power supply line can be reduced, and the electro-optical device 1A can be downsized.

<Third Embodiment>
FIG. 8 is a timing chart of the electro-optical device 1B according to the third embodiment of the invention.
In FIG. 8, γ2A indicates the voltage of the pixel electrode 55 when negative polarity writing is performed. Further, γ1B indicates the voltage of the pixel electrode 55 when the negative polarity writing is performed before the positive polarity writing is simulated, and γ1A is the pixel electrode when the positive polarity writing is simulated. 55 voltage is shown.
In the present embodiment, two methods for writing an image voltage based on an image signal to the pixel electrode 55 are different from those of the electro-optical device 1 according to the first embodiment.

The fifth method is a method of performing negative polarity writing as shown in the period from time t30 to t32 in FIG.
In this negative polarity writing method, the capacitor line drive circuit 30 supplies the voltage VCOML having the same potential as the voltage LCCOM of the common electrode 56 to the capacitor line Z, and then the scan line drive circuit 10 scans the selection voltage. In addition to being supplied to the line Y, the data line driving circuit 20 supplies a negative image signal having a potential lower than the voltage LCCOM of the common electrode 56 to the data line X.

The sixth method is a method of performing positive polarity writing in a pseudo manner as shown in the period from time t32 to t36 in FIG.
In the method of performing the positive polarity writing in a pseudo manner, first, the capacitor line driving circuit 30 supplies the voltage VCOML having the same potential as the voltage LCCOM of the common electrode 56 to the capacitor line Z, and then the scanning line driving circuit 10 In addition to supplying the selection voltage to the scanning line Y, the data line driving circuit 20 supplies a negative image signal having a potential lower than the voltage LCCOM of the common electrode 56 to the data line X. Next, after the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Y and the voltage γ1B of the pixel electrode 55 with respect to the voltage LCCOM of the common electrode 56 is stabilized, the capacitance line driving circuit 30 The voltage VCOMH is supplied to the capacitor line Z.
That is, in the method of performing positive polarity writing in a pseudo manner, the voltage line VCOMH is supplied to the capacitance line Z by the capacitance line driving circuit 30 after the negative polarity writing is performed by the fifth method described above.

According to this embodiment, there are the following effects.
(4) As a method of writing an image voltage based on an image signal to the pixel electrode 55, a method of performing negative polarity writing as a fifth method and a method of performing positive polarity writing as a sixth method in a pseudo manner , Provided. Here, in the case of performing negative polarity writing and in the case of performing pseudo polarity writing, an image signal for writing an image voltage to the pixel electrode 55 is set to have a potential lower than the voltage LCCOM of the common electrode 56. did. Therefore, as in the above-described conventional example, when positive polarity writing is performed, the voltage of the image signal is set higher than the voltage LCCOM of the common electrode 56, and when negative polarity writing is performed, the image is Compared with the case where the potential of the signal is lower than the voltage LCCOM of the common electrode 56, the voltage amplitude of the image signal can be reduced. Therefore, since the data line driving circuit 20 can be operated normally without being manufactured by a high breakdown voltage process, the driving voltage supplied to the data line driving circuit 20 can be lowered and the power consumption can be reduced.

<Fourth embodiment>
FIG. 9 is a timing chart of the electro-optical device 1C according to the fourth embodiment of the invention.
This embodiment is different from the electro-optical device 1B according to the third embodiment in that the voltage LCCOM of the common electrode 56 and the voltage VCOMH are set to the same potential.

  The electro-optical device 1 </ b> C has the following two methods as a method of writing an image voltage based on an image signal to the pixel electrode 55.

The seventh method is a method of performing negative polarity writing as shown in the period from time t40 to t42 in FIG.
In this negative polarity writing method, after the voltage VCOML is supplied to the capacitor line Z by the capacitor line driving circuit 30, the selection voltage is supplied to the scanning line Y by the scanning line driving circuit 10 and the data line driving circuit. 20, a negative image signal having a lower potential than the voltage LCCOM of the common electrode 56 is supplied to the data line X.

The eighth method is a method of performing positive polarity writing in a pseudo manner as shown in the period from time t42 to t46 in FIG.
In the method of performing the positive polarity writing in a pseudo manner, first, the capacitor line drive circuit 30 supplies the voltage VCOML to the capacitor line Z, and then the scan line drive circuit 10 supplies the selection voltage to the scan line Y. The data line driving circuit 20 supplies a negative image signal having a lower potential than the voltage LCCOM of the common electrode 56 to the data line X. Next, the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Y, and after the voltage γ1B of the pixel electrode 55 with respect to the voltage LCCOM of the common electrode 56 is stabilized, the capacitance line driving circuit 30 performs the common operation. A voltage VCOMH having the same potential as the voltage LCCOM of the electrode 56 is supplied to the capacitor line Z.
That is, in the method of performing the positive polarity writing in a pseudo manner, after the negative polarity writing is performed by the seventh method described above, the voltage VCOMH having the same potential as the voltage LCCOM of the common electrode 56 is obtained by the capacitor line driving circuit 30. Is supplied to the capacitor line Z.

  According to this embodiment, there is an effect similar to the effect described above.

<Fifth Embodiment>
FIG. 10 is a block diagram of a capacitive line driving circuit 30A according to the fifth embodiment of the present invention.
The present embodiment is different from the capacitive line drive circuit 30 according to the first embodiment in that there is an input end that is not connected anywhere at the input end of the capacitive line drive circuit 30A. For the sake of convenience, it is assumed that a voltage Hi-z is input to an input terminal that is not connected anywhere in the capacitor line driving circuit 30A.
The capacitor line drive circuit 30A includes a first unit capacitor line drive circuit 31A provided corresponding to the odd-numbered capacitor lines Z and a second unit capacitor provided corresponding to the even-numbered capacitor lines Z. A line drive circuit 32A.

FIG. 11 is a block diagram of the first unit capacitance line driving circuit 31A.
The first unit capacitor line drive circuit 31A includes a control signal generation circuit 301 and a voltage selection circuit 302A.

The input terminal of the voltage selection circuit 302A is connected to the output terminal of the control signal generation circuit 301 and the output terminal of the power supply circuit (not shown), and the corresponding capacitance line Z is connected to the output terminal of the voltage selection circuit 302A. Has been. Further, the input terminal of the voltage selection circuit 302A includes an input terminal that is not connected anywhere. The voltage selection circuit 302A receives the control signal CTRL from the control signal generation circuit 301, and receives the voltage VCOML and the voltage VCOMH from the power supply circuit. The voltage Hi-z is input to the input terminal that is not connected anywhere.
The voltage selection circuit 302A selects either the voltage VCOML or the voltage VCOMH according to the control signal CTRL and outputs the selected voltage.
The voltage selection circuit 302A outputs the voltage Hi-z at a predetermined timing.

FIG. 12 is a block diagram of the second unit capacitance line driving circuit 32A.
The second unit capacitor line drive circuit 32A includes an inverter 303 in addition to the control signal generation circuit 301 and the voltage selection circuit 302A described above.

The output terminal of the voltage selection circuit 302A is connected to the input terminal of the inverter 303, and the corresponding capacitor line Z is connected to the output terminal of the inverter 303.
The inverter 303 inverts the polarity of the voltage output from the voltage selection circuit 302A and outputs it.

FIG. 13 is a timing chart of the capacitor line driving circuit 30A.
In FIG. 13, the alternate long and short dash line indicates a floating state.

  The capacitor line driving circuit 30 according to the first embodiment is set to the voltage level of the polarity instruction signal SCPOL after a ½ horizontal scanning period after the scanning line driving circuit 10 stops supplying the selection voltage to the scanning line Y. In response, the voltage VCOML or the voltage VCOMH is supplied to the capacitor line Z. The capacitive line driving circuit 30A according to the present embodiment further supplies the voltage Hi-z to the capacitive line Z one horizontal scanning period after the voltage VCOML or the voltage VCOMH is supplied to the capacitive line Z. Then, the capacitor line Z to which the voltage Hi-z is supplied enters a floating state.

According to this embodiment, there are the following effects.
(6) After a half horizontal scanning period after the supply of the selection voltage to the scanning line Y is stopped by the scanning line driving circuit 10, the capacitive line driving circuit 30A responds to the voltage level of the polarity instruction signal SCPOL. The voltage VCOML or the voltage VCOMH was supplied to the capacitor line Z. Then, after one horizontal scanning period after the voltage VCOML or the voltage VCOMH is supplied to the capacitor line Z, the capacitor line drive circuit 30A supplies the voltage Hi-z to the capacitor line Z so that the capacitor line Z is in a floating state. . Therefore, since the period during which the voltage is supplied from the capacitor line driving circuit 30A to the capacitor line Z is shortened, power consumption can be reduced.

<Modification>
Note that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within a scope in which the object of the present invention can be achieved are included in the present invention.
For example, in each of the embodiments described above, 320 rows of scanning lines Y1 to Y320 and 240 columns of data lines X1 to X240 are provided, but the present invention is not limited thereto. For example, 480 rows of scanning lines Y1 to Y480 and 640 columns of data lines X1 to X640 may be provided.

  In each of the above-described embodiments, the liquid crystal included in the electro-optical devices 1, 1A, 1B, and 1C operates in the normally black mode. However, the liquid crystal is not limited thereto, and for example, operates in the normally white mode. It may be.

<Application example>
Next, an electronic apparatus to which the electro-optical device 1 according to the above-described embodiment is applied will be described.
FIG. 14 is a perspective view illustrating a configuration of a mobile phone 3000 to which the electro-optical device 1 is applied. The cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and the electro-optical device 1. By operating the scroll button 3002, the screen displayed on the electro-optical device 1 is scrolled.

  Note that electronic devices to which the electro-optical device 1 is applied include those shown in FIG. 14, personal computers, portable information terminals, digital still cameras, liquid crystal televisions, viewfinder type, monitor direct view type video tape recorders, car navigation systems. Examples of the apparatus include a device, a pager, an electronic notebook, a calculator, a word processor, a workstation, a videophone, a POS terminal, and a touch panel. The electro-optical device described above can be applied as a display unit of these various electronic devices.

1 is a block diagram of an electro-optical device according to a first embodiment of the invention. FIG. FIG. 3 is a block diagram of a capacitive line driving circuit included in the electro-optical device. FIG. 3 is a block diagram of a first unit capacity line driving circuit included in the capacity line driving circuit. It is a block diagram of the 2nd unit capacity line drive circuit with which the capacity line drive circuit is provided. 4 is a timing chart of the capacitance line driving circuit. 3 is a timing chart of the electro-optical device. 6 is a timing chart of an electro-optical device according to a second embodiment of the invention. 10 is a timing chart of an electro-optical device according to a third embodiment of the invention. 10 is a timing chart of an electro-optical device according to a fourth embodiment of the invention. It is a block diagram of the capacitive line drive circuit which concerns on 5th Embodiment of this invention. FIG. 3 is a block diagram of a first unit capacity line driving circuit included in the capacity line driving circuit. It is a block diagram of the 2nd unit capacity line drive circuit with which the capacity line drive circuit is provided. 4 is a timing chart of the capacitance line driving circuit. It is a perspective view which shows the structure of the mobile telephone to which the said electro-optical apparatus is applied. 10 is a timing chart of an electro-optical device according to a conventional example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C ... Electro-optical device, 10 ... Scanning line drive circuit, 20 ... Data line drive circuit, 30, 30A ... Capacitance line drive circuit, 50 ... Pixel, 53 ... Storage capacity, 54 ... Pixel capacity, 55 ... pixel electrode, 56 ... common electrode, 3000 ... mobile phone (electronic device), X ... data line, Y ... scanning line, Z ... capacitance line.

Claims (8)

A plurality of scanning lines, a plurality of data lines, a plurality of capacitance lines, and a plurality of pixel electrodes provided corresponding to intersections of the plurality of scanning lines and the plurality of data lines, and facing the pixel electrodes An electro-optical device comprising: a pixel capacitor having a common electrode; and a storage capacitor in which one electrode is connected to the capacitor line and the other electrode is connected to the pixel electrode,
A capacitor line driving circuit in which a first voltage and a second voltage having a lower potential than the first voltage are alternately selected, and the selected voltage is sequentially supplied to the plurality of capacitor lines;
A scanning line driving circuit for sequentially supplying a selection voltage for selecting the scanning line to the plurality of scanning lines;
A data line driving circuit for supplying an image signal to the plurality of data lines when the scanning line is selected;
Either the first voltage or the second voltage has the same potential as the voltage of the common electrode,
After the capacitance line driving circuit supplies either the first voltage or the second voltage to the capacitance line, the scanning line driving circuit supplies the selection voltage to the scanning line, and the data An image signal is supplied to the data line by a line driving circuit,
After the supply of the selection voltage to the scanning line is stopped by the scanning line driving circuit, either one of the first voltage or the second voltage is supplied to the capacitive line by the capacitive line driving circuit. Electro-optical device characterized. The electro-optical device according to claim 1.
When the second voltage is the same potential as the voltage of the common electrode, the voltage level of the image signal is set lower than the voltage level of the first voltage and higher than the voltage level of the common electrode. Electro-optical device characterized. The electro-optical device according to claim 1.
The electro-optical device, wherein the voltage level of the image signal is set higher than the voltage level of the first voltage when the first voltage is the same potential as the voltage of the common electrode. The electro-optical device according to claim 1.
The electro-optical device, wherein the voltage level of the image signal is set lower than the voltage level of the second voltage when the second voltage is the same potential as the voltage of the common electrode. The electro-optical device according to claim 1.
When the first voltage is the same potential as the voltage of the common electrode, the voltage level of the image signal is set higher than the voltage level of the second voltage and lower than the voltage level of the common electrode. Electro-optical device characterized. The electro-optical device according to any one of claims 1 to 5,
An electro-optical device, wherein after the supply of the selection voltage to the scanning line is stopped by the scanning line driving circuit, the capacitive line is brought into a floating state by the capacitive line driving circuit. The electro-optical device according to any one of claims 1 to 5,
After the supply of the selection voltage is stopped, either one of the first voltage and the second voltage is supplied to the capacitor line by the capacitor line driving circuit, and then the capacitor line is set in a floating state. An electro-optical device.   An electronic apparatus comprising the electro-optical device according to claim 1.

Images