JP2009003068A - Electro-optical device, driving method thereof, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optic device capable of reducing a peak current of alternating current drive. <P>SOLUTION: A signal line drive circuit 102 feeds a signal potential corresponding an image signal to three first signal lines by unit period during a selection period for selecting a predetermined scan line and feeds a reference potential VCOM 2 to three second signal lines paired with the three first signal lines during the unit period. Among a plurality of second signal lines SL11B-SLn3b, second signal lines except the three second signal lines, to which the reference potential is supplied, are electrically shut off from the power source. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for driving an electro-optical element such as a liquid crystal.

In a liquid crystal device, a driving method in which a vertical electric field in the light emission direction is applied to the liquid crystal and a driving method in which a horizontal electric field in a direction orthogonal to the light emission direction is applied to the liquid crystal are known. When a DC voltage is applied to the liquid crystal, image quality deterioration such as image sticking is caused. Therefore, in any driving method, an AC drive that applies an AC voltage to the liquid crystal is used.
In the driving method in which the vertical electric field is applied to the liquid crystal, for example, a pixel circuit shown in FIG. 10 is used. In this pixel circuit, when the scanning signal Y becomes high level, the transistor Tr is turned on, and the data potential Vdata supplied via the data line 10 is applied to the liquid crystal element 5 and held in the holding capacitor C. The liquid crystal element 5 is configured by sandwiching a liquid crystal LC between a pixel electrode 5a and a common electrode 5b. The transistor Tr and the pixel electrode 5a are formed on the element substrate, and the common electrode 5b is formed on the counter substrate. The element substrate and the counter substrate are bonded together with a gap, and liquid crystal is injected between them. The common electrode 5b formed on the counter substrate is shared by a plurality of pixel circuits, and a reference potential VCOM is supplied thereto. In such a circuit configuration, an alternating voltage is applied to the liquid crystal LC by alternately repeating a period in which the potential of the data potential Vdata is set to a high potential and a period in which the potential of the data potential Vdata is set to a low potential with reference to the reference potential VCOM.

  In a pixel circuit to which a lateral electric field driving method is applied, a first electrode and a second electrode are formed on an element substrate on which a switching transistor is formed. A technique is known in which positive and negative video signals with the same absolute value with respect to a fixed potential are applied to a first electrode and a second electrode, respectively (for example, Patent Document 1).

JP 2003-149654 A (paragraph number 0033)

  By the way, in the driving of the horizontal electric field, the common electrode 5b is not formed unlike the driving of the vertical electric field, and the potentials of the first electrode and the second electrode are inverted according to the polarity inversion period. In this polarity inversion operation, a reference potential is supplied to one electrode, and a gradation potential corresponding to a gradation to be displayed is supplied to the other electrode. In this case, if polarity inversion occurs simultaneously in a plurality of pixel circuits, a large current flows at that timing. For this reason, the power source that supplies the reference potential is required to have a driving capability sufficient to supply a large current. Here, the large current flows only in the period immediately after the polarity inversion, and almost no current flows in most of the periods. Therefore, in the conventional driving of the lateral electric field, the power source that supplies the reference potential is required to have a large driving capability corresponding to the peak current, and the circuit configuration of the power source is increased.

  This invention is made | formed in view of such a situation, and makes it a subject to reduce the magnitude | size of a peak current.

  In order to solve the above-described problem, an electro-optical device according to the present invention includes a plurality of first signal lines, a plurality of second signal lines paired with each of the plurality of first signal lines, and the plurality of the plurality of first signal lines. A plurality of scanning lines extending in a direction intersecting the first signal line and the plurality of second signal lines, and according to the intersection of the plurality of first signal lines or the plurality of second signal lines and the scanning line A plurality of pixels, a power source for supplying a predetermined reference potential, a signal line driving circuit for driving the plurality of first signal lines and the plurality of second signal lines, and the plurality of scanning lines are selected. A scanning line driver circuit sequentially selected for each period, and each of the plurality of pixels includes a first electrode, a second electrode, and each of the plurality of first signal lines and the first electrode. A first switching element provided in each of the plurality of second signal lines and the second electrode. A second switching element provided therebetween, an electro-optical material provided between the first electrode and the second electrode, the optical characteristic of which changes due to an electric field generated due to a potential difference between the electrodes, The selection period is divided into a plurality of unit periods, and the plurality of first signal lines are composed of a plurality of first signal line groups in which the first signal lines are grouped into a predetermined number. The second signal line includes a plurality of second signal line groups that are paired with each of the plurality of first signal line groups, and the signal line driver circuit includes the plurality of first signals in a first period. A signal potential is supplied to each of the line groups in a time-sharing manner for each unit period, and a second signal line including a second signal line group paired with the first signal line group for supplying the signal potential is electrically connected to the power source. Are connected to each other to supply the reference potential, and the other second signal lines are electrically connected to the power source. Cross and, in the second period, interchanging the second signal line and the first signal line, and supplying the signal potential and the reference potential.

According to the present invention, the polarity of the voltage written to the electro-optic element is reversed at a certain period. In the first period, since the first potential is supplied for each predetermined number of first signal lines, writing of the signal potential corresponding to the image signal to the pixel is executed in units of the predetermined number of pixels. In this case, the reference potential is supplied to the second electrode in the pixel where writing is performed. When the pixel is viewed from the power source, the wiring leading to the pixel is accompanied by a parasitic capacitance, which becomes a capacitive load. According to the present invention, it is not necessary to supply the reference potential to all pixels in one row, and the pixels that supply the reference potential are switched in a time division manner. Therefore, the magnitude of the peak current required for writing the signal can be reduced, and the driving capability necessary for the power supply to stably supply the reference potential can be reduced.
Here, in the second period, the first signal line and the second signal line are interchanged to supply the signal potential and the reference potential, and more specifically, each of the plurality of second signal line groups. A signal potential is supplied to each of the unit periods in a time-sharing manner, and a first signal line including a first signal line group paired with a second signal line group for supplying the signal potential is electrically connected to the power source. The reference potential is supplied, and the other first signal lines may be electrically disconnected from the power source.
In addition, the first period may be a selection period in which a predetermined scanning line is selected in a certain frame when the time required for writing an image signal to all pixels is one frame. In this case, the second period may be a selection period for selecting the predetermined scanning line of the next frame.

  Further, the signal line driver circuit starts supplying the signal potential to the second signal line group paired with the first signal line group supplying the signal potential in the first period. The supply of the reference potential is started, the supply of the reference potential is finished after the supply of the signal potential is finished, and in the second period, the first signal line and the second signal line are switched, It is preferable to supply the signal potential and the reference potential.

Although pulse-like noise is generated at the start and end timing of the supply of the reference potential, according to the present invention, the reference potential is already supplied before the signal potential is supplied, and the reference potential is supplied after the supply of the signal potential is ended. Since the supply of the potential is completed, the signal potential can be written in a stable state, and the signal potential can be accurately written while reducing the influence of noise. Further, since a reference potential is supplied to the second signal line in a unit period in which writing of a signal potential is performed in adjacent pixels in a certain frame, a so-called floating state can be avoided. If the second signal line is in a floating state, writing of the signal potential in the adjacent pixel affects the voltage held in the pixel due to the parasitic capacitance. However, according to the present invention, since the reference potential is supplied to the second signal line, crosstalk can be suppressed.
In the second period, the supply of the reference potential is started before the supply of the signal potential to the first signal line group that is paired with the second signal line group that supplies the signal potential. Then, after the supply of the signal potential is finished, the supply of the reference potential may be finished.

  Next, an electronic apparatus according to the present invention preferably includes the above-described electro-optical device. Such electronic devices include personal computers, mobile phones, and portable information terminals.

Next, the driving method of the electro-optical device according to the invention includes a plurality of pixels arranged in a grid pattern, and each of the plurality of pixels includes a first electrode, a second electrode, and the first electrode. A method of driving an electro-optical device having an electro-optical material provided between the electrode and the second electrode, the optical characteristics of which are changed by an electric field generated due to a potential difference between the electrodes. A pixel is selected sequentially for each pixel, and a signal potential corresponding to an image signal is supplied to one of the first electrode and the second electrode for each of a predetermined number of selected pixels, and the other electrode A predetermined reference potential is supplied to the pixel, and among the selected pixels, the first electrode and the second electrode are set to a high impedance state for pixels other than the pixel that supplies the reference potential to the other electrode. It is characterized by that.
According to this invention, since the first electrode and the second electrode are provided for each pixel, the predetermined reference potential can be supplied for each pixel. Here, for the pixels other than the pixel that supplies the reference potential to the other electrode, since the first electrode and the second electrode are in a high impedance state, the peak current associated with the writing of the signal potential can be reduced, It becomes possible to reduce the driving capability of the power source necessary for supplying the reference potential.

  Further, in the above-described driving method of the electro-optical device, in the pixel that supplies the first potential to the one electrode, the other electrode may include the signal potential before the signal potential is supplied to the one electrode. It is preferable that the supply of the reference potential is finished and the supply of the first reference potential is finished after the supply of the signal potential is finished. According to this driving method, the timing of supplying the signal potential and the reference potential can be shifted, so that the generation of noise can be suppressed. In addition, since the reference potential is supplied prior to the supply of the signal potential, a voltage corresponding to the image signal can be stably applied to the first electrode and the second electrode.

  The electro-optical device according to the embodiment of the present invention uses liquid crystal as an electro-optical material. The electro-optical device 1 includes a liquid crystal panel AA (an example of an electro-optical panel) as a main part. In the liquid crystal panel AA, an element substrate on which a thin film transistor (hereinafter referred to as “TFT”) is formed as a switching element and a counter substrate are opposed to each other, and the liquid crystal panel AA is attached with a certain gap therebetween. Is pinched.

  FIG. 1 is a block diagram showing the overall configuration of the electro-optical device 1 according to the first embodiment. The electro-optical device 1 includes a liquid crystal panel AA, a control circuit 108, and an image signal processing circuit 107. The liquid crystal panel AA is a transmissive type, but may be a transflective type or a reflective type. The liquid crystal panel AA includes an image display area 101, a signal line driving circuit 102, and a scanning side driving circuit 103 on the element substrate.

  The control circuit 108 is supplied with a vertical synchronization signal VSYNC, a horizontal synchronization signal HSYNC, and a dot clock signal DCK that are synchronized with the original image signal DATA. Based on these signals, the control circuit 108 generates X transfer start pulses XSP1 and XSP2, X clock signals XCK1 and XCK2, and a first frame signal FR1 and supplies them to the signal line drive circuit 102, and at the same time, a Y transfer start pulse. YSP1 and Y clock signal YCK1 are generated and supplied to the scanning side drive circuit 103. Further, the control circuit 108 includes a power supply circuit (not shown) that generates the reference potentials VCOM1 and VCOM2. The control circuit 108 supplies the reference potential VCOM1 to the scanning line driving circuit 103 and supplies the reference potential VCOM2 to the signal line driving circuit 102. To do.

  In the image display region 101, a plurality of pixels PX111, PX112... PXnm3 are formed in a matrix, and the transmittance can be controlled for each pixel. Light from the backlight (not shown) is emitted to the display surface via the pixels PX111, PX112... PXnm3. Thereby, gradation display by light modulation becomes possible. The image signal processing circuit 107 performs image processing such as γ correction and edge enhancement on the original image signal DATA to generate image signals D1, D2, and D3, which are sent to the signal line driving circuit 102 via the selection circuit 106. To do.

  In the image display area 101, m (m is a natural number of 2 or more) scanning lines GP1, GP2,... GPm are arranged in parallel along the X direction, while 3n (n is 2 or more). Natural number) first signal lines SL11a, SL12a,... SLn3a and 3n second signal lines SL11b, SL12b... SLn3b are arranged in parallel along the Y direction. The first signal line and the second signal line constitute a signal line group as 3n sets of SL11a and SL11b, SL12a and SL12b,... SLn3a and SLn3b. .., GPm and the first signal lines SL11a, SL12a,... SLn3a or the second signal lines SL11b, SL12b... SLn3b, corresponding to the intersection of the pixels PX111, PX112 of m rows × 3n columns. ... PXnm3 is arranged.

  An image signal or a reference potential signal is supplied from the signal line driver circuit 102 to the first signal lines SL11a, SL12a... SLn3a and the second signal lines SL11b, SL12b. Further, scanning signals are sequentially applied to the scanning lines GP1, GP2,. When any one scanning signal becomes active, an image signal (signal potential) applied to the corresponding first signal line and second signal line is applied to the pixel group arranged in the X direction connected to the scanning line. Or a reference potential is captured.

  FIG. 2 shows a circuit diagram of pixels P111, P112, P121, and PX122 extracted from all the pixels P111, P112. The pixel P112 includes n-type transistors SW201 and SW202, a first storage capacitor Cstg1, a second storage capacitor Cstg2, a third storage capacitor Cstg3, and an electro-optical element Clc. The electro-optic element Clc is composed of the first electrode 1a, the second electrode 1b, and an electro-optic material existing between them. This electro-optical material is a material whose optical characteristics change according to the applied electric field, that is, the voltage between the first electrode 1a and the second electrode 1b, and is a liquid crystal in this example. It should be noted that each pixel other than the pixel P112 has the same configuration.

  The first electrode 1a of the electro-optic element Clc is connected to the drain electrode of the first transistor SW201, while the second electrode 1b is connected to the drain electrode of the second transistor SW202. A second storage capacitor Cstg2 is provided between the drain electrode of the first transistor SW201 and a potential line (not shown), and a third storage capacitor Cstg3 is provided between the drain electrode of the second transistor SW202 and the potential line. It is done. Furthermore, a first storage capacitor Cstg1 is provided in parallel with the electro-optic element 13 between the drain electrode of the first transistor SW201 and the drain electrode of the second transistor SW202. Here, it is desirable that some or all of the first to third storage capacitors Cstg1, Cstg2, and Cstg3 are clearly formed as capacitive elements, but it is effective even if they are parasitic capacitances associated with the respective nodes. There is no change.

  The source electrode of the first transistor SW201 is connected to the first signal line SL12a, and the source electrode of the second transistor SW202 is connected to the second signal line SL12b. Further, the gate electrodes of the first and second transistors SW201 and SW202 are connected to the scanning line GP1. When the scanning signal applied to the scanning line GP1 is at a high level (active), both the first and second transistors SW201 and 202 are turned on. Then, the first potential applied to the first signal line SL12a is applied to the first electrode 1a of the electro-optic element Clc, and the second potential applied to the second signal line SL12b is applied to the electro-optic element Clc. Applied to the second electrode 1b. At this time, the voltage applied to the electro-optical element Clc is held by the first holding capacitor Cstg1. Thus, the transmittance of each pixel can be arbitrarily controlled by applying and holding an arbitrary voltage to the liquid crystal, which is an electro-optical material. Note that the polarity inversion in this embodiment is a state in which a reference potential is supplied as a first potential and a signal potential is used as a second potential, and a signal potential is supplied as a first potential and a reference potential as a second potential. This is done by replacing

  The first transistor SW201 and the second transistor SW202 function as switching elements. Incidentally, the notation of the source electrode and the drain electrode of the transistor described in this embodiment is used for the sake of convenience to designate the electrode in FIG. 2, and the vertical relationship of the voltage between the source and drain of the transistor is shown. It is not specified. The first and second transistors have been described as having n-type conductivity, but there is no change in the effects of the present invention even if they are p-type.

FIG. 3 shows the configuration of the signal line driver circuit 103 and its peripheral circuits. The signal line driving circuit 102 includes first and second signal line scanning circuits 104 and 105 and a switch group SW111... SW2n3.
The first (second) signal line scanning circuit 104 (105) is constituted by a shift register circuit, for example, and sequentially transfers the X transfer start pulse XSP1 (XSP2) in synchronization with the X clock signal XCK1 (XCK2). Then, sequential selection pulses PL11, PL12... PL1n (PL21, PL22... PL2n) are generated.

  The selection pulses PL11, PL12... PL1n output from the first signal line scanning circuit 104 are electrically connected / not connected to the signal transmission lines DL1, DL2, DL3 and the first signal lines SL11a, SL12a, SL13a, SL21a, SL22a, SL23a,. Control the conduction state. Similarly, the selection pulses PL21, PL22... PL2n output from the second signal line scanning circuit 105 are transmitted between the signal transmission lines DL4, DL5, DL6 and the second signal lines SL11b, SL12b, SL13b, SL21b, SL22b, SL23b, SLn3b. Control the conduction / non-conduction state. An image signal or a reference potential sent from the selection circuit 106 is input to the signal transmission lines DL1 to DL6, and the image signal or reference potential corresponding to the connection between the selection pulse and the switch group SW111. It is sent to the first or second signal line.

One driving example of the liquid crystal panel AA having the circuit block configuration will be described with reference to FIG.
First, at time t0, a scanning signal (high level) is applied to the scanning line GP1 to turn on the first and second transistors SW201 and SW202 of the plurality of pixels PX111, PX112, PX113... PXn13 connected thereto. The At this time, scanning signals (low level) in a non-conduction state are applied to the other scanning lines GP2, GP3,. At this time, only the pixels in the first row connected to the scanning line GP1 are in the conductive state in all the pixel groups. In this state, when an image signal (described later) or a reference potential VCOM2 is selectively applied to the first signal lines SL11a, SL12a ... and the second signal lines SL11b, SL12b ..., the electro-optical elements Clc of the corresponding pixels PX111, PX112 ... An image signal can be written into the. Then, after applying a non-conductive potential (low level) to the scanning line GP1 (t5), the same operation is sequentially performed on the scanning lines GP2, GP3,. Can write. In the following description, a period during which a high level scanning signal is supplied to each scanning line GP1, GP2,... GPm and each scanning line GP1, GP2,.

In the unit period Th1, the image signal is supplied from the selection circuit 106 to the signal transmission lines DL1, DL2, and DL3 connected to the switch group controlled by the first signal line scanning circuit 104, and is controlled by the second signal line scanning circuit 105. The reference potential VCOM2 is supplied from the selection circuit 106 to the signal transmission lines DL4, DL5, DL6 connected to the switch group.
In the subsequent unit period Th2, the reference potential VCOM2 is supplied from the selection circuit 106 to the signal transmission lines DL1, DL2, and DL3 connected to the switch group controlled by the first signal line scanning circuit 104, and the second signal line scanning circuit 105 is supplied. An image signal is supplied from the selection circuit 106 to the signal transmission lines DL4, DL5, and DL6 connected to the switch group controlled by the above.

  Here, as an example of an AC driving method for liquid crystal, so-called “scanning line inversion driving” in which the polarity is inverted in units of scanning lines is adopted. This is why the reference potential VCOM2 and the image signal are interchanged in the unit period Th1 and the unit period Th2. Even when scanning line inversion driving is performed, when attention is paid to a certain pixel, when an image signal is supplied to the first electrode 1a in one frame and the reference potential VCOM2 is supplied to the second electrode 1b, the first electrode is used in the next frame. A reference potential VCOM2 is supplied to 1a, and an image signal is supplied to the second electrode 1b.

  A method for writing an image signal to a pixel in the unit period Th1 will be specifically described. In a period from time t2 to time t3, the switch SW11a samples the image signal D111 supplied to the signal transmission line DL1 according to the selection pulse PL11 output from the first signal line scanning circuit 104, and first signal line SL11a. Output to. At this time, the switch SW11b applies the reference potential VCOM2 of the signal transmission line DL4 to the second signal line SL11b according to the selection pulse PL21 output from the second signal line scanning circuit 105. Thus, the image signal can be applied to the first signal line SL11a, the reference potential VCOM2 can be applied to the second signal line SL11b, and the voltage of (image signal −VCOM2) can be written to the corresponding electro-optical element Clc of the pixel PX111.

  Next, in a period from time t3 to time t4, the switch SW11a samples the image signal D211 supplied to the signal transmission line DL1 on the first signal line SL21a according to the selection pulse PL12. At this time, the reference potential VCOM2 supplied from the signal transmission line DL3 according to the selection pulse PL22 is applied to the second signal line SL21b forming a set by the switch SW11b. In this way, the sampling of the signal is sequentially performed in response to each selection pulse PL, and the first and second signal lines corresponding to the image signal or the reference potential supplied to the signal transmission line, and the tip thereof, become conductive. Write to the pixel.

In the unit period Th2, the roles of the first signal line scanning circuit 104 and the second signal line scanning circuit 105 are switched. In the unit period Th1, the selection circuit 106 outputs image signals to the signal transmission lines DL1 to DL3 and outputs the reference potential VCOM2 to the signal transmission lines DL4 to DL6. However, in the unit period Th2, the signal transmission line DL1. This is because the reference potential VCOM2 is output to .about.DL3 and the image signal is output to the signal transmission lines DL4 to DL6.
Specifically, based on the selection pulse PL11 output from the first signal line scanning circuit 104, the switch SW11a samples the reference potential VCOM2 supplied to the signal transmission line DL1 and outputs it to the first signal line SL11a. Based on the selection pulse PL21 output from the second signal line scanning circuit 105, the switch SW11b samples the reference potential VCOM2 supplied to the signal transmission line DL4 and outputs it to the second signal line SL11b. In the same manner, signal sampling is sequentially performed in accordance with sequential selection pulses PL12, PL22,.

Here, the difference from the conventional electro-optical device will be described with reference to FIG.
In the conventional electro-optical device (A), the power source driving load of the reference potential VCOM at the time of writing the image signal to the pixel is not only the holding capacitor 505 and the liquid crystal capacitor 506 of the pixel being written, but also all the non-selected states. There is a parasitic capacitance 504 between the pixel signal line 502 and the reference potential VCOM and a parasitic capacitance 503 between the scanning line 501 and the common electrode VCOM. Although the total driving load related to the common electrode VCOM is a very large capacity of, for example, 10 nF to several μF, depending on the panel size, an extremely large current driving capability is required to stabilize the potential in a short period during pixel writing. Is required. For this reason, the power supply circuit having the reference potential VCOM generally cannot be reduced in power consumption.

  On the other hand, in the electro-optical device (B) of the present invention, only a corresponding pixel column is connected to the reference potential VCOM when an arbitrary one period is taken, and extra driving is performed to the power source of the reference potential VCOM. Do not give load. Since the capacity as the driving load is small, a power supply circuit having a lower driving capability can be used. Further, by sequentially sampling the reference potential VCOM, the peak current value of the reference potential VCOM can be leveled within the above-described unit periods Th1, Th2,..., And a power supply circuit having a reduced maximum current driving capability can be used. With these effects, an electro-optical device with low power consumption can be realized.

The other features of the drive surface will be described again with reference to FIG.
The sampling start timing (t1) of the selection pulse PL21 is earlier than the timing (t2) at which the sampling of the image signal of the corresponding pixel is started. The sampling end timing (t4) of the selection pulse PL21 is earlier than the timing (t3) at which the sampling of the image signal of the corresponding pixel ends. This is to suppress crosstalk due to parasitic capacitance or the like between adjacent pixels. For example, the reference potential VCOM2 is sampled on the second signal line SL11b here, but a switch provided between the second signal line SL11b and the signal transmission line DL4 when signal writing is performed on an adjacent pixel. If the SW 211 (FIG. 1) is in a non-conducting state, the second signal line SL11b is in a so-called floating state, and the reference potential VCOM2 is affected by the write signal of an adjacent pixel and the potential fluctuates. In order to avoid this, the reference potential is kept fixed before and after the timing of the image signal sample. As a result, it is possible to realize a high-quality electro-optical device having no display abnormality such as a ghost and having a high gradation reproducibility.

In the embodiment described above, so-called “scanning line inversion driving” in which the polarity is inverted in units of scanning lines has been adopted as an example of the alternating current driving method of the liquid crystal. As another AC driving method for liquid crystal, so-called “frame inversion driving” in which the polarity is inverted for each screen may be used, or the polarity may be inverted for each vertical pixel column. For example, when frame inversion driving is adopted, the selection circuit 106 outputs the image signal and the reference potential VCOM2 to the signal transmission lines DL1 to DL6 as shown in FIG.
Here, the frame signal FR1 becomes a high level in the first frame F1 (odd number frame) and becomes a low level in the second frame F2 (even number frame). Then, the selection circuit 106 outputs an image signal (signal potential) to the transmission signal lines DL1 to DL3 and outputs a reference potential VCOM2 to the transmission signal lines DL4 to DL6 during a period in which the frame signal FR1 is at a high level. In addition, the selection circuit 106 outputs the reference potential VCOM2 to the transmission signal lines DL1 to DL3 and outputs the image signal (signal potential) to the transmission signal lines DL4 to DL6 while the frame signal FR1 is at a low level. As a result, polarity inversion is performed on all pixels of the entire screen in units of frames.

Next, an electronic apparatus to which the electro-optical device 1 according to the above-described embodiment is applied will be described. FIG. 7 shows a configuration of a mobile personal computer to which the electro-optical device 1 is applied. The personal computer 2000 includes the electro-optical device 1 as a display unit and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002.
FIG. 8 shows a configuration of a mobile phone to which the electro-optical device 1 is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and the 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.
FIG. 9 shows a configuration of a portable information terminal (PDA: Personal Digital Assistants) to which the electro-optical device 1 is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and the electro-optical device 1 as a display unit. When the power switch 4002 is operated, various types of information such as an address book and a schedule book are displayed on the electro-optical device 1.
The electronic apparatus to which the electro-optical device 1 is applied includes, in addition to those shown in FIGS. 7 to 9, a digital still camera, a liquid crystal television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, Examples include electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, and devices equipped with touch panels. The electro-optical device 1 described above can be applied as a display unit of these various electronic devices.

1 is a circuit block diagram showing an overall configuration of an electro-optical device 1 according to an embodiment of the present invention. It is a circuit diagram which shows the structural example of the pixel of liquid crystal panel AA. 2 is a block diagram showing a detailed configuration of a signal line driving circuit 102. FIG. It is a timing chart for demonstrating operation | movement of the apparatus. It is explanatory drawing for demonstrating the difference with the conventional electro-optical apparatus. 6 is a timing chart for explaining an operation example in frame inversion driving. 1 is a perspective view showing a configuration of a personal computer as an example of an electronic apparatus to which an electro-optical device is applied. It is a perspective view which shows the structure of the mobile telephone which is an example of the electronic device to which the electro-optical apparatus is applied. It is a perspective view which shows the structure of the portable information terminal which is an example of the electronic device to which the electro-optical device is applied. It is a circuit diagram which shows the structure of the conventional pixel circuit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electro-optical device, SL11a-SLn3a ... 1st signal line, SL11b-SLn3b ... 2nd signal line, GP1-GPm ... Scanning line, 102 ... Signal line drive circuit, PX111-PXnm3 ... Pixel, SW201 ... 1st transistor, SW202: second transistor, 1a: first electrode, 1b: second electrode, Clc: electro-optic element, Cstg1, Cstg2, Cstg3: holding capacitor, 103: scanning line driving circuit, Th1, Th2: unit period.

Claims (5)

A plurality of first signal lines;
A plurality of second signal lines paired with each of the plurality of first signal lines;
A plurality of scanning lines extending in a direction intersecting with the plurality of first signal lines and the plurality of second signal lines;
A plurality of pixels provided in accordance with intersections of the plurality of first signal lines or the plurality of second signal lines and the scanning lines;
A power supply for supplying a predetermined reference potential;
A signal line driving circuit for driving the plurality of first signal lines and the plurality of second signal lines;
A scanning line driving circuit for sequentially selecting the plurality of scanning lines for each selection period;
Each of the plurality of pixels includes a first electrode, a second electrode, a first switching element provided between each of the plurality of first signal lines and the first electrode, and the plurality of pixels. Caused by a potential difference between the second switching element provided between each of the second signal lines and the second electrode, and between the first electrode and the second electrode. An electro-optic material whose optical properties change due to the electric field generated by
The selection period is divided into a plurality of unit periods,
The plurality of first signal lines are composed of a plurality of first signal line groups in which the first signal lines are grouped into a predetermined number.
The plurality of second signal lines include a plurality of second signal line groups that are paired with each of the plurality of first signal line groups,
The signal line driving circuit includes:
In the first period, a signal potential is supplied to each of the plurality of first signal line groups in a time-division manner for each unit period, and a second signal line paired with the first signal line group that supplies the signal potential. A second signal line including a group is electrically connected to the power source to supply the reference potential, and the other second signal lines are electrically disconnected from the power source;
In the second period, the first signal line and the second signal line are switched to supply the signal potential and the reference potential.
An electro-optical device. The signal line driving circuit includes:
In the first period, supply of the reference potential is started before starting the supply of the signal potential to the second signal line group that is paired with the first signal line group that supplies the signal potential, After the supply of the signal potential is finished, the supply of the reference potential is finished,
In the second period, the first signal line and the second signal line are switched to supply the signal potential and the reference potential.
The electro-optical device according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 1. A plurality of pixels arranged in a grid pattern, each of the plurality of pixels being provided between a first electrode, a second electrode, and the first electrode and the second electrode; An electro-optical device driving method having an electro-optical material whose optical characteristics change due to an electric field generated due to a potential difference between electrodes,
Select pixels sequentially for each row,
Among the selected pixels, for each predetermined number of pixels, a signal potential corresponding to an image signal is supplied to one of the first electrode and the second electrode, and a predetermined reference potential is supplied to the other electrode. ,
For the pixels other than the pixel that supplies the reference potential to the other electrode among the selected pixels, the first electrode and the second electrode are in a high impedance state.
A driving method for an electro-optical device.   In the pixel that supplies the first potential to the one electrode, the reference potential is supplied to the other electrode before starting the supply of the signal potential to the one electrode, and the supply of the signal potential is performed. 5. The method of driving the electro-optical device according to claim 4, wherein the supply of the first reference potential is terminated after the termination.

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