CN101482680B - Electro-optical device, method of driving electro-optical device, and electronic apparatus - Google Patents

Abstract

The present invention provides an electro-optic device (1A), comprising: a first substrate having a plurality of scanning lines (110), a plurality of data lines (120), a plurality of common lines (130) and a plurality of pixel circuits (150); and a first substrate 2 substrates. The pixel circuit (150) has a pixel electrode (155), a storage capacitor (153) and a switch element (151). The second substrate has a common electrode (156) connected to the common line (130). The electro-optical device (1A) has: a common line drive circuit (103A), which supplies a drive signal of the first potential or a second potential to the common line (130); a data line drive circuit (102), which supplies an image signal to the data line (120) ; and a scan line drive circuit (101), which supplies a control signal to the scan line (110). The electro-optical device (1A) includes an equalization circuit (201) for equalizing the data line and the common line.

Description

Electro-optical device, driving method thereof, and electronic device

This application is a divisional application with the filing date of June 1, 2006, the application number of 200610088527.X, and the title of the invention being an electro-optical device, its driving method and electronic equipment. the

technical field

The invention relates to an electro-optic device, a driving method of the electro-optic device and electronic equipment. the

Background technique

Conventionally, electro-optical devices such as liquid crystal display devices for liquid crystal display of images are well known. This electro-optical device has, for example, the following configuration. the

FIG. 11 is a plan view of an electro-optical device 1 according to a conventional example of the present invention. the

The electro-optical device 1 includes a liquid crystal panel AA, a scanning line driving circuit 101 , a data line driving circuit 102 , and a common line driving circuit 103 . the

The liquid crystal panel AA includes: an element substrate 100 in which thin film transistors (hereinafter referred to as TFTs) 151 as switching elements are arranged in a matrix; an opposing substrate is arranged opposite to the element substrate 100; and between the opposing substrates. the

The scanning line driving circuit 101 and the data line driving circuit 102 are formed on the element substrate 100 of the liquid crystal panel AA. the

On the element substrate 100, formed are: a plurality of scanning lines 110 arranged at predetermined intervals; a plurality of data lines 120 substantially perpendicular to these scanning lines 110 and arranged at predetermined intervals; and a plurality of common lines 130 , and the plurality of scanning lines 110 are substantially parallel and arranged alternately. the

At intersections of each scan line 110 and each data line 120, a pixel circuit 150 is provided. In addition to the TFT 151 described above, the pixel circuit 150 further includes: a pixel electrode 155 ; and a storage capacitor 153 , one end of which is connected to the pixel electrode 155 and the other end is connected to the common line 130 . the

The scan line 110 is connected to the gate of the TFT 151 , the data line 120 is connected to the source of the TFT 151 , and the pixel electrode 155 and the storage capacitor 153 are connected to the drain of the TFT 151 . Therefore, the TFT 151 connects and disconnects the data line 120, the pixel electrode 155 and the storage capacitor 153 according to the control signal from the scanning line 110. the

The counter substrate has a common electrode 156 facing the pixel electrode 155 . The common electrode 156 is connected to the common line 130 through the opposing conductive portions 105 provided at the four corners of the element substrate 100 and the common wiring 106 for connecting the opposing conductive portions 105 . the

The common line driving circuit 103 is used to supply a driving signal of a first potential or a second potential higher than the first potential to the common line 130 . the

The data line driving circuit 102 supplies an image signal to the data line 120 at a potential higher than the first potential when the potential of the common electrode 156 is the first potential, and supplies an image signal at a potential higher than the second potential when the potential of the common electrode 156 is the second potential. The low potential supplies an image signal to the data line 120 . the

The scanning line driving circuit 101 supplies a control signal for turning on and off the TFT 151 to the scanning line 110 . the

In the electro-optical device 1 above, the potential of the common electrode 156 is inverted between a first potential and a second potential higher than the first potential by the common line driving circuit 103 (hereinafter referred to as common inversion driving). When the potential of the common electrode 156 is the first potential, the image signal is supplied to the data line 120 by the data line drive circuit 102 at a potential higher than the first potential (hereinafter referred to as positive polarity writing). In the case of the second potential, an image signal is supplied to the data line 120 at a potential lower than the second potential (hereinafter referred to as negative polarity writing). the

FIG. 12 is a timing chart at the time of positive polarity writing in the electro-optical device 1 according to the conventional example. FIG. 13 is a timing chart at the time of negative polarity writing in the electro-optical device 1 according to the conventional example. 12 and 13 show the case of writing with the same gray scale. In FIGS. 12 and 13 , VCOM is the potential of the common electrode 156 , SOURCE is the potential of the data line 120 , GATE is the potential of the scanning line 110 , and PIX is the potential of the pixel electrode 155 . the

In positive polarity writing, as shown in FIG. 12, first, the potential VCOM of the common electrode 156 is changed to the first potential VCL by the common line driving circuit 103, and the potential GATE of the scanning line 110 is supplied from the scanning line driving circuit 101 to VCL. This is a control signal of the potential VGH to bring the TFT 151 into an on state. the

Next, at time t1, an image signal is supplied through the data line driving circuit 102, the potential SOURCE of the data line 120 is raised from the potential VP1 to the potential VP5, and is written into the pixel electrode 155 and the storage capacitor 153 through the TFT 151. the

Next, at time t2, the TFT 151 is turned off by the scanning line driver circuit 101 . Thus, a potential difference between the first potential VCL of the common electrode 156 and the potential VP5 written to the pixel electrode 155 is applied to the liquid crystal and held by the storage capacitor 153 . the

Next, at time t3, the potential VCOM of the common electrode 156 is raised from the first potential VCL to the second potential VCH by the common line driving circuit 103 . Then, the potential difference between the potential PIX of the pixel electrode 155 and the potential VCOM of the common electrode 156 rises to the potential VP2 together with the common electrode 156 as it is. At this time, although the data line 120 is disconnected from the pixel electrode 155 by the TFT 151 , the potential SOURCE of the data line 120 rises to the same potential VP2 as the potential PIX of the pixel electrode 155 due to capacitive coupling with the common line 130 . the

Next, in writing with negative polarity, as shown in FIG. GATE becomes a control signal of potential VGH, and turns TFT 151 into an on state. the

Next, at time t5, the image signal is supplied from the data line driving circuit 102, the potential SOURCE of the data line 120 is lowered from the potential VP2 to the potential VP6, and is written into the pixel electrode 155 and the storage capacitor 153 through the TFT 151 . the

Next, at time t6, the scanning line driving circuit 101 turns the TFT 151 into an off state. Thus, a potential difference between the second potential VCH of the common electrode 156 and the potential VP6 written to the pixel electrode 155 is applied to the liquid crystal and held by the storage capacitor 153 . the

Next, at time t7, the potential VCOM of the common electrode 156 is lowered from the second potential VCH to the first potential VCL by the common line driving circuit 103 . Then, the potential difference between the potential PIX of the pixel electrode 155 and the potential VCOM of the common electrode 156 drops to the potential VP1 together with the common electrode 156 as it is. At this time, although the data line 120 is disconnected from the pixel electrode 155 by the TFT 151 , the potential SOURCE of the data line 120 drops to the same potential VP1 as the potential PIX of the pixel electrode 155 due to capacitive coupling with the common line 130 . the

According to such an electro-optical device 1 , there is an effect that the image sticking phenomenon on the liquid crystal screen of the liquid crystal panel AA can be prevented. the

However, in the above-mentioned conventional electro-optic device 1, when the potential SOURCE of the data line 120 is raised from the potential VP1 to the potential VP5, and when the potential SOURCE of the data line 120 is lowered from the potential VP2 to the potential VP6, it consumes power, thus increasing power consumption. In addition, the time for writing an image signal into the pixel electrode 155 also increases. the

Furthermore, since capacitive coupling occurs between the data line 120 and the common line 130 when performing positive polarity writing, if the potential VCOM of the common electrode 156 is raised from the first potential VCL to the second potential VCH, the data line 120 The potential SOURCE of the pixel electrode 155 rises to the same potential VP2 as the potential PIX of the pixel electrode 155 . In addition, since capacitive coupling occurs between the data line 120 and the common line 130 when negative polarity writing is performed, when the potential VCOM of the common electrode 156 drops from the second potential VCH to the first potential VCL, the potential of the data line 120 SOURCE falls to the same potential VP1 as the potential PIX of the pixel electrode 155 . Therefore, there is a risk of applying an excessive voltage to the data line driving circuit 102 and damaging the data line driving circuit 102 . the

In view of the above problems, electro-optical devices provided with a precharge circuit having a large capacitance have been proposed (for example, see Patent Document 1). In addition, an electro-optical device including a precharge circuit for supplying a driving voltage to a data line has also been proposed (for example, see Patent Document 2). the

According to the electro-optic device including the precharge circuit disclosed in Patent Document 1, when the potential of the common electrode is raised during positive polarity writing, the electric charge is moved between the large capacitance of the precharge circuit and the data line to prevent The potential of the data line rises to the same potential as the pixel electrode. Also, when the potential of the common electrode is lowered during negative writing, charges are transferred between the large capacitance of the precharge circuit and the data line to prevent the potential of the data line from falling to the same potential as the pixel electrode. the

Therefore, without supplying a driving voltage to the data line, the rise or fall of the potential of the data line can be suppressed, so that power consumption can be reduced. In addition, damage to the data line driving circuit can also be prevented. the

In addition, according to the electro-optic device including the precharge circuit described in Patent Document 2, before raising the potential of the common electrode during positive polarity writing, the potential of the data line is raised to the level of the common electrode by supplying a driving voltage from the precharge circuit in advance. electrodes at the same potential. Also, before lowering the potential of the common electrode during negative polarity writing, the potential of the data line is lowered to the same potential as the common electrode by supplying a drive voltage from the precharge circuit in advance. the

Therefore, by supplying the driving voltage, the potential difference before and after writing the image signal can be reduced, and thus the time for writing the image signal to the pixel electrode can be shortened. the

Patent Document 1: JP-A-2004-354758 Gazette

Patent Document 2: JP-A-2004-191536 Gazette

However, in recent years, portable devices such as mobile phones equipped with electro-optical devices have been widely spread. However, for such electro-optical devices, the increase in power consumption accompanying higher functionality and higher performance has become a problem. Therefore, an electro-optical device capable of reducing power consumption is required. However, the electro-optical device disclosed in Patent Document 1 above cannot be considered to have sufficiently met such demands. Also, in the electro-optic device disclosed in Patent Document 2, although power consumption during data line writing can be suppressed, it is difficult to reduce power consumption overall because power is consumed in the precharge circuit. the

Contents of the invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electro-optical device capable of reducing power consumption, a driving method of the electro-optic device, and an electronic device. the

In order to solve the above problems, the present invention provides the following electro-optical device, driving method of the electro-optical device, and electronic equipment. the

The electro-optical device of the present invention includes: a first substrate having a plurality of scanning lines, a plurality of data lines substantially perpendicular to these scanning lines, a plurality of common lines arranged alternately substantially parallel to the scanning lines, and a plurality of data lines corresponding to the scanning lines. A plurality of pixel circuits arranged at the intersection of the line and the above-mentioned data line; the second substrate is arranged opposite to the first substrate; and the electro-optic material is arranged between the above-mentioned first substrate and the above-mentioned second substrate; the above-mentioned pixel circuit has : a pixel electrode; a storage capacitor, one end connected to the pixel electrode and the other end connected to the above-mentioned common line; and a switch element, used to make the above-mentioned data line, the above-mentioned pixel electrode and the above-mentioned storage capacitor according to the control signal from the above-mentioned scanning line. The connection is disconnected; the above-mentioned second substrate has a common electrode connected to the above-mentioned common line; the electro-optic device has: a common line drive circuit, which is used to supply a driving signal of a first potential or a second potential higher than the first potential to the common electrode. line; a data line drive circuit for supplying an image signal to the data line at a potential higher than the first potential when the potential of the common electrode is the first potential, and the potential of the common electrode is the second potential , an image signal is supplied to the data line at a potential lower than the second potential; and a scanning line driving circuit is used to supply a control signal for turning the switching element on and off to the scanning line; it is characterized in that the common The line drive circuit has: a drive signal supply circuit for supplying a drive signal of the first potential or the second potential; and a drive signal supply switch for connecting and disconnecting the drive signal supply circuit and the common line; An equalizing circuit is provided for connecting and disconnecting the data line and the common line to equalize the data line and the common line. the

According to the present invention, positive polarity writing is performed in the following steps. the

First, the common electrode is brought to the first potential by the common line driving circuit, and a control signal is supplied from the scanning line driving circuit to the scanning lines to bring the switching elements into a conductive state. Next, an image signal is supplied to the data line from the data line driving circuit, and written into the pixel electrode and the storage capacitor through the switching element. Next, the switching element is turned off by the scanning line driving circuit. Thereby, the potential difference between the first potential of the common electrode and the potential written to the pixel electrode is applied to the liquid crystal and held by the storage capacitor. the

Next, the common electrode is raised from the first potential to the second potential by the common line driving circuit. Then, the potential difference between the potential of the pixel electrode and the common electrode rises together with the common electrode as it is. At this time, although the data line is disconnected from the pixel electrode by the switching element, the potential of the data line rises to the same potential as the pixel electrode due to capacitive coupling with the common line. the

Therefore, the common line drive circuit is configured including the drive signal supply circuit and the drive signal supply switch, the drive signal supply switch is temporarily turned off, and the equalization circuit connects the data line and the common line. Then, without the supply of the drive voltage from the drive signal supply circuit, the transfer of charge occurs between the data line and the common electrode via the common line. Therefore, the data line has substantially the same potential as the common electrode, not the pixel electrode. the

In addition, negative polarity writing is performed in the following procedure. the

First, the common electrode is brought to the second potential by the common line driving circuit, and a control signal is supplied to the scanning lines from the scanning line driving circuit to bring the switching elements into a conductive state. Next, an image signal is supplied to the data line from the data line driving circuit, and written into the pixel electrode and the storage capacitor through the switching element. Next, the switching element is turned off by the scanning line driving circuit. Thereby, the potential difference between the second potential of the common electrode and the potential written to the pixel electrode is applied to the liquid crystal and held by the storage capacitor. the

Next, the common electrode is lowered from the second potential to the first potential by the common line driving circuit. Then, the potential difference between the potential of the pixel electrode and the common electrode decreases together with the common electrode as it is. At this time, although the data line is disconnected from the pixel electrode by the switching element, the potential of the data line drops to the same potential as the pixel electrode due to capacitive coupling with the common line. the

Here, the common line drive circuit is configured including a drive signal supply circuit and a drive signal supply switch, the drive signal supply switch is temporarily turned off, and the equalization function circuit connects the data line and the common line. Then, without the supply of the drive voltage from the drive signal supply circuit, the transfer of charge occurs between the data line and the common electrode via the common line. Therefore, the data line has substantially the same potential as the common electrode, not the pixel electrode. the

As described above, when the drive signal supply switch is temporarily turned off, there is no drive voltage supply from the drive signal supply circuit, and the movement of charges occurs between the data line and the common electrode. , The potential of the common electrode changes, so the power consumption can be reduced. the

Furthermore, the potential of the data line is changed in a direction favorable for writing an image signal in the next step, and the potential of the common electrode is also changed in a direction favorable for the reverse phase operation in the next step. Therefore, it is possible to shorten the writing time of the image signal to the pixel electrode and the time required for inversion of the common electrode. the

Also, since the data line has substantially the same potential as the common electrode, not the pixel electrode, the potential does not rise as high as that of the pixel electrode when positive polarity writing is performed. On the other hand, when negative polarity writing is performed, the potential does not drop as low as that of the pixel electrode. Thus, a voltage exceeding the withstand voltage capability of the data line driving circuit can be prevented from acting. the

In addition, in the above-mentioned electro-optical device, it is preferable that the data line drive circuit has a shift register, and when an activation signal is input to the shift register, the activation signal is transmitted in synchronization with a clock to sequentially output samples. Signal. the

According to the present invention, when an activation signal is input to the shift register, the activation signal is transmitted in synchronization with a clock to sequentially output sampling signals. According to the sampling signal, an image signal is sequentially supplied to each of the plurality of data lines. the

For dot sequential driving using a shift register, since the data line driving circuit only needs to have a simple structure, it can be easily manufactured and the circuit scale can be suppressed. the

In addition, in conventional electro-optical devices that perform dot sequential driving, it is difficult to secure a time for writing an image signal to a pixel electrode as the pixel density increases. And according to the electro-optic device that carries out dot sequential drive with the above-mentioned equalization function circuit, even if the pixel density is increased, because the potential of the data line changes to the direction that is beneficial to the image signal writing in the next step, so the pixel electrode can still be ensured. The time to write the image signal. the

In addition, in the above-mentioned electro-optic device, preferably, the above-mentioned data line drive circuit has a demultiplexing circuit including a plurality of transmission gates, and if the transmission gate receives a control signal and an inverted control signal obtained by inverting the control signal, , then corresponding to the above-mentioned control signal and the above-mentioned anti-phase control signal to conduct on and off; the above-mentioned multiple transmission gates selectively distribute the analog image signal. the

According to the present invention, one terminal of the transmission gate is connected to the input terminal of the demultiplexing circuit, and the other terminal of the transmission gate is connected to the output terminals. Furthermore, to the input terminal of the demultiplexing circuit, for example, an analog image signal obtained by mixing a plurality of image signals such as R (red), G (green), and B (blue) is supplied, and is synchronized with the supply of the analog image signal. , making each control signal valid in turn. the

Then, the transmission gates are sequentially changed from the high-impedance state to the conductive state, and each data line is sequentially selected. Thereby, among the analog image signals, only image signals of R (red), G (green), and B (blue) are sequentially output from the output terminal and supplied to corresponding data lines. the

Since such a demultiplexing circuit is provided, a plurality of image signals can be mixed and supplied, so that the number of transmission paths can be suppressed, the circuit scale can be suppressed, and power consumption can be reduced. the

In addition, in the above-mentioned electro-optical device, it is preferable that the data line driving circuit has a D/A conversion circuit for converting a digital image signal into an analog image signal, and supplies the supplied digital image signal as the analog image signal to the The data lines are driven digitally sequentially. the

According to the present invention, for example, a digital image signal is converted into an analog image signal corresponding to a sampled signal from a shift register. Then, digital line sequential driving is performed by sequentially supplying an analog image signal to each data line. the

In this way, digital image signals can be supplied to the data line driving circuit by sequentially driving the digital lines. Therefore, compared with the case where an analog image signal is supplied to the data line driving circuit, the noise immunity on the transmission path can be improved. the

Description of drawings

FIG. 1 is a plan view showing an electro-optical device according to a first embodiment of the present invention. the

FIG. 2 is a timing chart of the electro-optical device at the time of positive polarity writing using the common inversion driving method according to the above-mentioned embodiment. the

FIG. 3 is a timing chart of the electro-optical device at the time of negative polarity writing using the common inversion driving method according to the above-mentioned embodiment. the

4 is a plan view of an electro-optical device according to a second embodiment of the present invention. the

5 is a plan view of an electro-optical device according to a third embodiment of the present invention. the

6 is a plan view of an electro-optical device according to a fourth embodiment of the present invention. the

FIG. 7 is a circuit block diagram of the electro-optical device according to the above embodiment. the

FIG. 8 is a perspective view showing the structure of the electro-optical device 1 according to the above-mentioned embodiment and modification. the

Fig. 9 is a Z-Z' sectional view in Fig. 8 . the

Fig. 10 is a perspective view showing the structure of a cellular phone using the electro-optical device. the

Fig. 11 is a plan view of an electro-optical device according to a conventional example of the present invention. the

FIG. 12 is a timing chart at the time of positive polarity writing in the electro-optical device according to the conventional example. the

13 is a timing chart at the time of negative polarity writing in the electro-optical device according to the conventional example. the

Symbol Description

1, 1A, 1B, 1C, 1D, 1E…electro-optical device, 21…driving signal supply circuit, 22…driving signal supply switch, 101, 402…scanning line driving circuit, 102, 102A, 102B, 102C, 102D, 401… Data line driving circuit, 103, 103A...common line driving circuit, 110...scanning line, 120...data line, 130...common line, 150...pixel circuit, 151...TFT, 153...storage capacitor, 155, 406...pixel circuit, 156...Common electrode, 201, 201A...Balance function circuit, 222...Switch mechanism, 331...Shift register, 332...Analog switch, 333...D/A conversion circuit, 441, 441A...Multichannel distribution circuit. the

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings. In addition, in the description of the following embodiments, the same reference numerals are attached to the same components to omit or simplify the description. the

<1. First embodiment>

FIG. 1 is a plan view of an electro-optical device 1A according to a first embodiment of the present invention. The difference between the electro-optical device 1A and the electro-optical device 1 of FIG. 11 is that it has an equalization function circuit 201 and a common line driving circuit 103A. the

The equalization function circuit 201 is used for synchronizing with the control signal CP to connect and disconnect the data line 120 and the common line 130 . Specifically, in this embodiment, the equalization function circuit 201 connects the data line 120 and the common line 130 when the control signal CP is at “H” level, and connects the data line 120 and the common line 130 when the control signal CP is at “L” level. The common line 130 is disconnected. the

The common line drive circuit 103A includes: a drive signal supply circuit 21 for supplying a drive signal at a first potential or a second potential higher than the first potential; and a drive signal supply switch 22 for supplying the drive signal to the circuit 21. and the common line 130 for connection and disconnection. the

The drive signal supply circuit 21 includes a power supply IC (Integrated Circuit) 211 for alternately outputting the first potential or the second potential at a predetermined cycle. the

The drive signal supply switch 22 includes: a drive IC 221 for generating a control signal CC; and a switch mechanism 222 for turning on and off in accordance with the control signal CC from the drive IC 221 . Specifically, in this embodiment, the switch mechanism 222 disconnects the drive signal supply circuit 21 and the common line 130 when the control signal CC is at "H" level, and connects the drive signal supply circuit 21 and the common line 130 when the control signal CC is at "L" level. The signal supply circuit 21 and the common line 130 . the

The common line driving circuit 103A supplies the common line 130 with the first potential or the second potential alternately output from the power supply IC 211 at a predetermined cycle when the switch mechanism 222 is turned on in response to the control signal CC generated by the driving IC 221 . the

FIG. 2 is a timing chart of the electro-optical device 1A at the time of positive polarity writing using the common inversion driving method. FIG. 3 is a timing chart of the electro-optical device 1A during negative polarity writing using the common inversion driving method. 2 and 3 show the case of writing with the same gray scale. In addition, in FIGS. 2 and 3 , VCOM is the potential of the common electrode 156 , SOURCE is the potential of the data line 120 , GATE is the potential of the scanning line 110 , and PIX is the potential of the pixel electrode 155 . the

In positive polarity writing, as shown in FIG. 2 , first, the potential VCOM of the common electrode 156 is changed to the first potential VCL by the common line driving circuit 103A, and the potential GATE of the scanning line 110 is changed to the first potential VCL from the scanning line driving circuit 101. This is a control signal of the potential VGH to bring the TFT 151 into an on state. The potential SOURCE of the data line 120 is substantially the same potential as the potential VCOM of the common electrode 156 due to the connection between the data line 120 and the common line 130 by an equalization function circuit 201 as an equalization circuit described later. the

Next, at time t1, the image signal is supplied from the data line driving circuit 102, the potential SOURCE of the data line 120 is raised from the potential VCL to the potential VP5, and is written into the pixel electrode 155 and the storage capacitor 153 through the TFT 151 . the

Next, at time t2, the TFT 151 is turned off by the scanning line driver circuit 101 . Thus, a potential difference between the first potential VCL of the common electrode 156 and the potential VP5 written to the pixel electrode 155 is applied to the liquid crystal and held by the storage capacitor 153 . the

Next, at time t3, the potential VCOM of the common electrode 156 is raised from the first potential VCL to the second potential VCH by the common line driving circuit 103A. Then, the potential difference between the potential PIX of the pixel electrode 155 and the potential VCOM of the common electrode 156 rises to the potential VP2 together with the common electrode 156 as it is. At this time, although the data line 120 is disconnected from the pixel electrode 155 by the TFT 151 , the potential SOURCE of the data line 120 rises to the same potential VP2 as the potential PIX of the pixel electrode 155 due to capacitive coupling with the common line 130 . the

Therefore, at time t3, control signals CC and CP are changed from potential VCPL to potential VCPH. Then, the switch mechanism 222 is turned off, and the equalization function circuit 201 is connected to the data line 120 and the common line 130 . Then, without the supply of the drive voltage from the drive signal supply circuit 21 , charge transfer occurs between the data line 120 and the common electrode 156 through the common line 130 . Therefore, the potential SOURCE of the data line 120 becomes substantially the same potential as the potential VCOM of the common electrode 156, not the potential PIX of the pixel electrode 155. the

Next, at time t4, the control signals CC and CP are changed from the potential VCPH to the potential VCPL. Then, the switch mechanism 222 is turned on, and the equalization function circuit 201 disconnects the data line 120 and the common line 130 . Therefore, although the data line 120 is disconnected from the pixel electrode 155 by the TFT 151, the potential SOURCE of the data line 120 rises to the second potential VCH together with the potential VCOM of the common electrode 156 because of capacitive coupling with the common line 130 . the

In this way, by temporarily changing the control signals CC and CP to the potential VCPH, the potential SOURCE of the data line 120 becomes substantially the same potential as the potential VCOM of the common electrode 156 . Next, since the data line 120 and the common line 130 are capacitively coupled, by changing the control signals CC and CP to the potential VCPL, the potential SOURCE of the data line 120 rises to the second potential VCH together with the potential VCOM of the common electrode 156. roughly the same potential. the

Next, in writing with negative polarity, as shown in FIG. GATE becomes a control signal of potential VGH, and turns TFT 151 into an on state. The potential SOURCE of the data line 120 is substantially the same potential as the potential VCOM of the common electrode 156 due to the connection between the data line 120 and the common line 130 by the above-mentioned equalization function circuit 201 . the

Next, at time t5, the image signal is supplied from the data line driving circuit 102, the potential SOURCE of the data line 120 is lowered from the potential VCH to the potential VP6, and is written into the pixel electrode 155 and the storage capacitor 153 through the TFT 151 . the

Next, at time t6, the scanning line driving circuit 101 turns the TFT 151 into an off state. Thus, a potential difference between the second potential VCH of the common electrode 156 and the potential VP6 written to the pixel electrode 155 is applied to the liquid crystal and held by the storage capacitor 153 . the

Next, at time t7, the potential VCOM of the common electrode 156 is lowered from the second potential VCH to the first potential VCL by the common line driving circuit 103A. Then, the potential difference between the potential PIX of the pixel electrode 155 and the potential VCOM of the common electrode 156 drops to the potential VP1 together with the common electrode 156 as it is. At this time, although the data line 120 is disconnected from the pixel electrode 155 by the TFT 151, due to capacitive coupling with the common line 130, the potential SOURCE of the data line 120 drops to the same potential VP1 as the potential PIX of the pixel electrode 155. the

Therefore, at time t7, control signals CC and CP are changed from potential VCPL to potential VCPH. Then, the switch mechanism 222 is turned off, and the equalization function circuit 201 is connected to the data line 120 and the common line 130 . Then, without the supply of the drive voltage from the drive signal supply circuit 21 , charge transfer occurs between the data line 120 and the common electrode 156 through the common line 130 . Therefore, the potential SOURCE of the data line 120 becomes substantially the same potential as the potential VCOM of the common electrode 156 , not the potential PIX of the pixel electrode 155 . the

Next, at time t8, the control signals CC and CP are changed from the potential VCPH to the potential VCPL. Then, the switch mechanism 222 is turned on, and the equalization function circuit 201 disconnects the data line 120 and the common line 130 . Therefore, although the data line 120 is disconnected from the pixel electrode 155 by the TFT 151, due to capacitive coupling with the common line 130, the potential SOURCE of the data line 120 and the potential VCOM of the common electrode 156 drop to the first potential VCL. the

In this way, by temporarily changing the control signals CC and CP to the potential VCPH, the potential SOURCE of the data line 120 becomes substantially the same potential as the potential VCOM of the common electrode 156 . Next, since the data line 120 and the common line 130 are capacitively coupled, by changing the control signals CC and CP to the potential VCPL, the potential SOURCE of the data line 120 rises to the first potential VCL together with the potential VCOM of the common electrode 156. roughly the same potential. the

According to this embodiment, there are the following effects. the

(1) Because when the switch mechanism 222 is temporarily turned off, there is no drive voltage supply from the drive signal supply circuit 21, and the movement of charge occurs between the data line 120 and the common electrode 156, and the data can be made use of the charge. The potentials of the line 120 and the common electrode 156 are changed, so that power consumption can be reduced. the

(2) The potential of the data line 120 is changed in a direction favorable for writing an image signal in the next step, and the potential of the common electrode 156 is also changed in a direction favorable for the reverse phase operation in the next step. Therefore, it is possible to shorten the writing time of the image signal to the pixel electrode 155 and the time required for the phase inversion of the common electrode 156 . the

(3) Since the data line 120 has substantially the same potential as the common electrode 156 instead of the pixel electrode 155, the potential does not rise as high as that of the pixel electrode 155 when positive polarity writing is performed. On the other hand, when negative polarity writing is performed, the potential does not drop as low as that of the pixel electrode 155 . Thus, a voltage exceeding the withstand voltage capability of the data line driving circuit 102 can be prevented from acting. the

<2. Second Embodiment>

FIG. 4 is a plan view of an electro-optical device 1B according to a second embodiment of the present invention. The difference between the electro-optic device 1B and the electro-optic device 1A in FIG. 1 is the structure of the data line driving circuit 102A. the

The data line driving circuit 102A is provided with: a shift register 331 for sequentially outputting sampling signals by transmitting the start signal synchronously with a clock when a start signal is input; 331 sampling signals to select each data line 120 in turn. the

According to the above-mentioned data line driving circuit 102A, when an activation signal is input to the shift register 331, the shift register 331 outputs a sampling signal, and the analog switch 332 sequentially selects each data line 120 according to the sampling signal from the shift register 331. Then, dot sequential driving is performed by supplying an image signal to the data line 120 selected by the analog switch 332 . the

The timing chart of the electro-optical device 1B according to this embodiment is the same as that of the electro-optical device 1A. Also, the operation from time t3 to time t4 in FIG. 2 and the operation from time t7 to time t8 in FIG. 3 are performed during the blanking period of the electro-optical device 1B. the

According to the present embodiment, in addition to the above-mentioned (1) to (3), the following effects are obtained. the

(4) For dot sequential driving using a shift register, since the data line driving circuit 102A has a simple structure, it can be easily manufactured and the circuit scale can be suppressed. the

(5) With conventional electro-optical devices that perform dot sequential driving, it is difficult to secure the time for writing image signals to pixel electrodes as the pixel density increases. However, with the above-mentioned electro-optic device 1B having the equalization function circuit 201 as an equalization circuit and performing dot sequential driving, even if the pixel density is increased, the potential of the data line 120 changes in a direction favorable to the next image signal writing. , so the time for writing an image signal to the pixel electrode 155 can be ensured. the

<3. The third embodiment>

FIG. 5 is a plan view of an electro-optical device 1C according to a third embodiment of the present invention. The difference between the electro-optical device 1C and the electro-optical device 1B of FIG. 4 is the structure of the data line driving circuit 102B. the

The data line driving circuit 102B is provided with a digital line sequential circuit, and the digital line sequential circuit includes: a shift register 331 that, when an activation signal is input, sequentially outputs sampling signals by transmitting the activation signal in synchronization with a clock; and D/ The A (digital/analog) conversion circuit 333 is used to convert the supplied digital image signal into an analog image signal. the

According to the above-mentioned data line driving circuit 102B, when an activation signal is input to the shift register 331, the shift register 331 outputs a sampling signal, and the D/A conversion circuit 333 converts a digital image signal corresponding to the sampling signal from the shift register 331. into an analog image signal. Then, digital line sequential driving is performed by supplying an analog image signal to each data line 120 . the

The timing chart of the electro-optical device 1C according to this embodiment is the same as that of the electro-optical device 1A. Also, the operation from time t3 to time t4 in FIG. 2 and the operation from time t7 to time t8 in FIG. 3 are performed during the blanking period of the electro-optic device 1C. the

According to the present embodiment, in addition to the above-mentioned (1) to (3), the following effects are obtained. the

(6) By sequentially driving digital lines, digital image signals can be supplied to the data line driving circuit 102B. Therefore, compared with the case where an analog image signal is supplied to the data line driving circuit 102B, noise resistance on the transmission path can be improved. the

<4. Fourth Embodiment>

FIG. 6 is a plan view of an electro-optical device 1D according to a fourth embodiment of the present invention. The difference between the electro-optical device 1D and the electro-optical device 1C of FIG. 5 is the structure of the data line driving circuit 102C. the

The data line driving circuit 102C includes a demultiplexing circuit 441 , and outputs a plurality of image signals based on the supplied analog image signal SEG obtained by mixing a plurality of image signals in response to the control signal SEL. the

FIG. 7 is a circuit block diagram of the electro-optical device 1E. The electro-optical device 1E shows an implementation example of the equalization function circuit 201 , the demultiplexing circuit 441 and the switch mechanism 222 as the equalization circuit included in the electro-optical device 1D in FIG. 6 . the

The data line driving circuit 102D is composed of n demultiplexing unit circuits A1 to An. Here, n is a natural number greater than or equal to 2. the

The demultiplexing unit circuits A1 to An have first, second, and third transfer gates 461 , 462 , and 463 , respectively. Specifically, in the demultiplexing unit circuit Am (for example, m is a natural number less than or equal to n), one terminal of the first to third transmission gates 461 to 463 is all connected to the input terminal SINm, and the other terminal is connected to the input terminal SINm. Connect to output terminals SOUTm1-SOUTm3 respectively. the

The output terminals SOUTm1 to SOUTm3 are respectively connected to the data lines 120 of R (red), G (green), and B (blue). That is, each demultiplexing unit circuit Am supplies an image signal to each sub-pixel of R (red), G (green), and B (blue). the

An analog image signal SEGm obtained by mixing image signals of R (red), G (green), and B (blue) colors is input to the input terminal SINm. the

The R control signal RSEL and the inverted R control signal RSELB obtained by inverting the R control signal RSEL are supplied to the control terminals of the first transfer gates 461 of the demultiplexing unit circuits A1 to An. the

When the R control signal RSEL and the inverted R control signal RSELB are enabled, the transmission gate 461 is turned on, and the image signal of R (red) is supplied to the R (red) according to the analog image signal input from the input terminal SINm. The data line 120. the

The G control signal GSEL and the inverted G control signal GSELB obtained by inverting the G control signal GSEL are supplied to the control terminals of the second transfer gates 462 of the demultiplexing unit circuits A1 to An. the

When the G control signal GSEL and the inverted G control signal GSELB are enabled, the transfer gate 462 is turned on, and the G (green) image signal is supplied to the G (green) in accordance with the analog image signal input from the input terminal SINm. The data line 120. the

The B control signal BSEL and the inverted B control signal BSELB obtained by inverting the B control signal BSEL are supplied to the control terminals of the third transfer gates 463 of the demultiplexing unit circuits A1 to An. the

When the B control signal BSEL and the inverted B control signal BSELB are enabled, the transfer gate 463 is turned on, and the B (blue) image signal is supplied to the B (blue) image signal in accordance with the analog image signal input from the input terminal SINm. The data line 120. the

The above demultiplexing circuit 441A operates as follows. the

The analog image signals SEG1-SEGn are supplied to the input terminals SIN1-SINn of the demultiplexing unit circuits A1-An, and the R control signal RSEL and the inverted R control signal RSELB, the G control signal GSEL and the inverted G control signal GSELB and B Either one of the control signal BSEL and the inverted B control signal BSELB becomes active. Thereby, a specific data line 120 is selected from the data lines 120 of the respective colors of R (red), G (green), and B (blue), and an image signal is supplied to the selected data line 120 . the

Therefore, image signals of R (red), G (green), and B (blue) can be extracted from an analog image signal obtained by mixing image signals of R (red), G (green), and B (blue). the

The timing chart of the electro-optical device 1E according to this embodiment is the same as that of the electro-optical device 1A. In addition, the operation from time t3 to time t4 in FIG. 2 and the operation from time t7 to time t8 in FIG. conduct. the

According to the present embodiment, in addition to the above-mentioned (1) to (3), the following effects are obtained. the

(7) With the above-mentioned demultiplexing circuit 441A, since a plurality of video signals can be mixed and supplied, the number of transmission paths can be limited, the circuit scale can be suppressed, and power consumption can be reduced. the

<5. Modifications>

In addition, the present invention is not limited to the above-mentioned embodiments, and modifications, improvements, and the like within the range that can achieve the object of the present invention are included in the present invention. the

For example, a drive signal supply switch that connects and disconnects the common line and the common line drive circuit may be provided outside the common line drive circuit that supplies a drive signal to the common line. the

In addition, the common line driving circuit may also be provided on the element substrate. the

In addition, although the same drive signal is supplied to the counter electrode and the storage capacitor, different drive signals may be supplied respectively. the

In addition, the control signal CP supplied to the equalization function circuit and the control signal CC supplied to the above-mentioned drive signal supply switch may be signals of different systems with different operation timings. the

<6. Electro-optic device>

Fig. 8 is a perspective view showing the structure of the electro-optical device 1 according to the above embodiment and modification, and Fig. 9 is a Z-Z' sectional view in Fig. 8 . the

The electro-optical device 1 is accommodated in a casing 400 (shown by a dotted line in FIG. 9 ). The electro-optic device 1 has: an element substrate 451 on which the pixel electrodes 406 and the like are formed; an opposing substrate 452 disposed opposite to the element substrate 451 and on which the common electrode 156 and the like are formed; liquid crystal 455 as an electro-optic substance provided on the element substrate 451 and Between the opposing substrates 452 ; and the backlight 450 as a light source is disposed on the lower side of the element substrate 451 (the side opposite to the opposing substrate 452 ) for irradiating light to the liquid crystal 455 . The element substrate 451 is formed of glass or a semiconductor, and various circuits and the like are formed on the element substrate 451 using TFT (Thin Film Transistor: thin film transistor). In addition, the counter substrate 452 is formed of a transparent material such as glass. the

A sealing member 454 is provided on the outer periphery of the opposing substrate 452 to seal the gap between the element substrate 451 and the opposing substrate 452 . The sealing member 454 forms a space for sealing the liquid crystal 455 together with the element substrate 451 and the counter substrate 452 . In the sealing member 454 , a spacer 453 is mixed in order to maintain a gap between the element substrate 451 and the counter substrate 452 . In addition, an opening for sealing the liquid crystal 455 is formed in the sealing member 454 , and the opening is sealed with a sealing material 456 after the liquid crystal 455 is sealed. the

Here, a data line driving circuit 401 for driving data lines is formed on the surface of the element substrate 451 facing the substrate 452 and outside the side of the sealing member 454, and the data line driving circuit 401 extends in the Y direction. Furthermore, on this side, a plurality of connection electrodes 457 are formed, and various signals are input through the connection electrodes 457 . In addition, scanning line driving circuits 402 for driving scanning lines are formed on both sides of the above-mentioned one side of the sealing member 454, and the scanning line driving circuits 402 extend in the X direction. the

<7. Electronic equipment>

Next, an electronic device using the electro-optical device 1 according to the above-mentioned embodiment will be described. FIG. 10 shows the structure of a mobile phone using the electro-optical device 1 . A cellular phone 3000 has a plurality of operation buttons 3001, scroll buttons 3002, and an electro-optical device 1 as a display unit. By operating the scroll button 3002, the screen displayed on the electro-optical device 1 is scrolled. the

Claims (6)

1. An electro-optical device, wherein, Equipped with: a pair of substrates facing each other across the electro-optic material; Multiple scan lines; a plurality of data lines substantially orthogonal to the scan lines; a plurality of common lines arranged approximately parallel to and alternately with the above-mentioned scanning lines; A pixel electrode arranged corresponding to the intersection of the above-mentioned scanning line and the above-mentioned data line; a switch element, which disconnects the connection between the data line and the pixel electrode according to the control signal from the scanning line; a storage capacitor, one end of which is connected to the above-mentioned pixel electrode, and the other end is connected to the above-mentioned common line; a common line drive circuit for supplying a driving signal of a first potential or a second potential higher than the first potential to the common line; A data line drive circuit for supplying an image signal to the data line at a potential higher than the first potential when the potential of the common line is the first potential, and for supplying an image signal to the data line when the potential of the common line is the second potential. supplying an image signal to the data line at a potential lower than the second potential; and a scanning line driving circuit, which supplies a control signal for turning on and off the switching element to the scanning line; Its characteristics are: An equalization circuit is provided for the data line and the common line, when the potential of the common line is raised from the first potential to the second potential by the common line drive circuit during positive polarity writing, and when the potential of the common line is increased from the first potential to the second potential in the negative polarity writing. During permanent writing, when the potential of the common line is lowered from the second potential to the first potential by the common line driving circuit, disconnection is performed so that the data line and the common line have the same potential. 2. The electro-optical device according to claim 1, characterized in that: The above-mentioned data line driving circuit has a shift register which, when an activation signal is input, transmits the activation signal in synchronization with a clock to sequentially output sampling signals. 3. The electro-optical device according to claim 1, characterized in that: The above data line drive circuit has a demultiplexing circuit including a plurality of transfer gates, and when the transfer gate receives a control signal and an inversion control signal obtained by inverting the control signal, it performs a process according to the control signal and the inversion control signal. On and off; the analog image signal is selectively distributed by the above-mentioned multiple transmission gates. 4. The electro-optical device according to claim 1, characterized in that: The data line driving circuit has a D/A conversion circuit for converting digital image signals into analog image signals, and is a digital line sequential drive for converting the supplied digital image signals into analog image signals and supplying them to the data lines. 5. An electronic device characterized by: An electro-optical device according to any one of claims 1 to 4 is provided. 6. A method for driving an electro-optical device, the electro-optic device having: A pair of substrates facing each other across the electro-optic material; Multiple scan lines; a plurality of data lines substantially orthogonal to the scan lines; a plurality of common lines arranged approximately parallel to and alternately with the above-mentioned scanning lines; A pixel electrode arranged corresponding to the intersection of the above-mentioned scanning line and the above-mentioned data line; a switch element, which disconnects the connection between the data line and the pixel electrode according to the control signal from the scanning line; a storage capacitor, one end of which is connected to the above-mentioned pixel electrode, and the other end is connected to the above-mentioned common line; a common line drive circuit for supplying a driving signal of a first potential or a second potential higher than the first potential to the common line; A data line drive circuit for supplying an image signal to the data line at a potential higher than the first potential when the potential of the common line is the first potential, and for supplying an image signal to the data line when the potential of the common line is the second potential. supplying an image signal to the data line at a potential lower than the second potential; and a scanning line driving circuit, which supplies a control signal for turning on and off the switching element to the scanning line; The driving method of the electro-optic device is characterized by: Setting: a drive signal supply circuit, which supplies the drive signal of the first potential or the second potential to the common line drive circuit; and a drive signal supply switch, which connects and disconnects the drive signal supply circuit and the common line; include: In the positive polarity writing step, the drive signal supply switch is turned on, the common line is set to the first potential, and a control signal is supplied from the scan line drive circuit to the scan line, and the switch element is set to In a conduction state, an image signal is supplied to the data line from the data line driving circuit, and written into the pixel electrode and the storage capacitor through the switching element; a positive polarity writing and holding step, wherein the switching element is turned on by the scanning line driving circuit, and a potential difference between the first potential of the common line and the potential written to the pixel electrode is applied to the liquid crystal, held by the above-mentioned storage capacitor; a positive polarity write potential raising step, wherein the common line is raised from the first potential to the second potential by the drive signal supply circuit; a negative polarity writing and holding step, wherein the switching element is turned on by the scanning line driving circuit, and a potential difference between the second potential of the common line and the potential written in the pixel electrode is applied to the liquid crystal, held by the aforementioned storage capacitor; and a negative polarity write potential lowering step, wherein the common line is lowered from the second potential to the first potential by the drive signal supply circuit; Repeat the above steps, In the step of increasing the positive polarity write potential, after the drive signal supply switch is temporarily turned off and the data line and the common line are connected, the drive signal supply switch is turned on again, and the driving The signal supply circuit raises the common line from the first potential to the second potential, In the step of lowering the negative polarity write potential, after the drive signal supply switch is temporarily turned off and the data line and the common line are connected, the drive signal supply switch is turned on again to pass the drive signal The supply circuit lowers the common line from the second potential to the first potential.

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