Patent Publication Number: US-11043178-B2

Title: Electro-optical device, driving method for electro-optical device, and electronic apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2018-161122, filed Aug. 30, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The disclosure relates to an electro-optical device, a driving method for the electro-optical device, and an electronic apparatus. 
     2. Related Art 
     A liquid crystal device is known as one of electro-optical devices, for example. The liquid crystal device forms an image by utilizing dielectric anisotropy of a liquid crystal and optical rotation of light in a liquid crystal layer. In the liquid crystal device, scanning lines and signal lines are arranged in an image display region, and pixels are arranged in a matrix at intersection points of the scanning lines and the signal lines. A pixel transistor is disposed in the pixel, and an image is formed by supplying an image signal to each pixel via the pixel transistor. 
     As a method for obtaining an image with high display quality in a liquid crystal device, for example, as described in JP-A-2012-150496, a driving method is known in which a data line supplying an image signal is divided into a plurality of blocks, and a plurality of the data lines in each block are sequentially selected in one horizontal period to supply the image signal, accordingly a writing time to the pixels is secured and display quality is improved (demultiplexer driving method). 
     However, further high resolution and high speed driving are desired in the future, and there is a problem that it becomes difficult to secure the writing time to the pixels as the resolution is increased and the driving speed is increased. 
     SUMMARY 
     An electro-optical device according to the present disclosure includes a plurality of signal lines, a plurality of scanning lines, pixels arranged corresponding to intersections of the plurality of signal lines and the plurality of scanning lines, image signal lines arranged respectively corresponding to k signal lines among the plurality of signal lines, k switches arranged between the image signal lines and the k signal lines respectively, a selection signal output circuit configured to output a selection signal for selecting the k switches, and an image signal output circuit configured to output an image signal to the pixels via the image signal lines, wherein the selection signal output circuit outputs a selection signal for simultaneously selecting a set of switches, which correspond to a set of adjacent signal lines, among the k switches in a partial period obtained by time-dividing a horizontal scanning period, and outputs a selection signal for selecting remaining switches among the k switches one at a time in a remaining period of the time-divided horizontal scanning period, and the image signal output circuit supplies a same image signal to a set of adjacent signal lines corresponding to the simultaneously selected set of switches in a partial period obtained by time-dividing the horizontal scanning period. 
     In the electro-optical device described above, the selection signal output circuit may change, at predetermined time intervals, a combination of the set of switches that are simultaneously selected. 
     In the electro-optical device described above, the selection signal output circuit may perform p-time speed driving that supplies a same image signal to the pixels p tunes for each vertical scanning period, and may change, p times or 2/p times in p vertical scanning periods, a combination of the set of switches that are simultaneously selected. 
     In the electro-optical device described above, the selection signal output circuit may simultaneously select two sets of switches, which respectively correspond to two sets of adjacent signal lines, among the k switches in a partial time period obtained by time-dividing the horizontal scanning period, and may supply a first image signal to a first set of adjacent signal lines corresponding to a first set of switches and also supply a second image signal to a second set of adjacent signal lines corresponding to a second set of switches. 
     In the electro-optical device described above, a vertical scanning period may include a first horizontal scanning period and a second horizontal scanning period, and the selection signal output circuit may change a combination of the set of switches that are simultaneously selected in the first horizontal scanning period and the second horizontal scanning period. 
     In the electro-optical device described above, the selection signal output circuit may supply an image signal, which is to be supplied to any one signal line of the set of adjacent signal lines corresponding to the set of switches that are simultaneously selected, to also the other signal line of the set of adjacent signal lines corresponding to the set of switches that are simultaneously selected. 
     In the electro-optical device described above, the image signal output circuit may supply an image signal, which is obtained by averaging image signals in a plurality of vertical scanning periods, to a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected. 
     There is a driving method for the electro-optical device according to the present disclosure, and the electro-optical device includes a plurality of signal lines, a plurality of scanning lines, pixels arranged corresponding to intersections of the plurality of signal lines and the plurality of scanning lines, image signal lines arranged respectively corresponding to k signal lines among the plurality of signal lines, k switches arranged between the image signal lines and the k signal lines respectively, a selection signal output circuit configured to output a selection signal for selecting k switches, and an image signal output circuit configured to output an image signal to the pixels via the image signal lines, the driving method including outputting by the selection signal output circuit a selection signal for simultaneously selecting a set of switches, which correspond to a set of adjacent signal lines, among the k switches in a partial period obtained by time-dividing a horizontal scanning period, and outputting a selection signal for selecting remaining switches among the k switches one at a time in a remaining period of the time-divided horizontal scanning period; and supplying by the image signal output circuit a same image signal to a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected in a partial period obtained by time-dividing the horizontal scanning period. 
     In the driving method for the electro-optical device described above, the selection signal output circuit may change, at predetermined time intervals, a combination of the set of switches that are simultaneously selected. 
     In the driving method for the electro-optical device described above, the selection signal output circuit may perform p-time speed driving that supplies a same image signal to the pixels p times for each vertical scanning period, and may change, p times or 2/p times in p vertical scanning periods, a combination of the set of switches that are simultaneously selected. 
     In the driving method for the electro-optical device described above, the selection signal output circuit may simultaneously select two sets of switches, which respectively correspond to two sets of adjacent signal lines, among the k switches in a partial time period obtained by time-dividing the horizontal scanning period, and may supply a first image signal to a first set of adjacent signal lines corresponding to a first set of switches and also supplies a second image signal to a second set of adjacent signal lines corresponding to a second set of switches. 
     In the driving method for the electro-optical device described above, a vertical scanning period may include a first horizontal scanning period and a second horizontal scanning period, and the selection signal output circuit changes a combination of the set of switches that are simultaneously selected in the first horizontal scanning period and the second horizontal scanning period. 
     In the driving method for the electro-optical device described above, the selection signal output circuit may supply an image signal, which is to be supplied to any one signal line of a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected, to also the other signal line of a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected. 
     In the driving method for the electro-optical device described above, the image signal output circuit may supply an image signal, which is obtained by averaging image signals in a plurality of vertical scanning periods, to a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected. 
     An electronic apparatus according to the present disclosure includes the electro-optical device described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a configuration of a projector, which is an example of an electronic apparatus of First Exemplary Embodiment. 
         FIG. 2  is a circuit block diagram illustrating a configuration of an electro-optical device. 
         FIG. 3  is a circuit diagram illustrating a configuration of a pixel configuring the electro-optical device. 
         FIG. 4  is a circuit diagram illustrating a configuration of a signal line driving circuit. 
         FIG. 5A  is a timing chart illustrating a driving method for the electro-optical device. 
         FIG. 5B  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 5C  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 5D  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 5E  is a tuning chart illustrating the driving method for the electro-optical device. 
         FIG. 5F  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 5G  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 5H  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 6A  is a table showing gradations for each frame period. 
         FIG. 6B  is a table showing the gradations for each frame period. 
         FIG. 6C  is a table showing the gradations for each frame period. 
         FIG. 6D  is a table showing the gradations for each frame period. 
         FIG. 6E  is a table showing the gradations for each frame period. 
         FIG. 6F  is a table showing the gradations for each frame period. 
         FIG. 6G  is a table showing the gradations for each frame period. 
         FIG. 6H  is a table showing the gradations for each frame period. 
         FIG. 7A  is a timing chart illustrating a driving method for an electro-optical device according to Second Exemplary Embodiment. 
         FIG. 7B  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 7C  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 7D  is a timing chart illustrating the driving method for the electro-optical device. 
         FIG. 8A  is a table showing gradations for each frame period. 
         FIG. 8B  is a table showing the gradations for each frame period. 
         FIG. 8C  is a table showing the gradations for each frame period. 
         FIG. 8D  is a table showing the gradations for each frame period. 
         FIG. 9  is a timing chart illustrating a driving method for an electro-optical device according to Third Exemplary Embodiment. 
         FIG. 10A  is a table showing gradations for each frame period. 
         FIG. 10B  is a table showing the gradations for each frame period. 
         FIG. 10C  is a table showing the gradations for each frame period. 
         FIG. 10D  is a table showing the gradations for each frame period. 
         FIG. 11  is a timing chart illustrating a driving method for an electro-optical device according to Fourth Exemplary Embodiment. 
         FIG. 12A  is a table showing gradations for each frame period. 
         FIG. 12B  is a table showing the gradations for each frame period. 
         FIG. 12C  is a table showing the gradations for each frame period. 
         FIG. 12D  is a table showing the gradations for each frame period. 
         FIG. 12E  is a table showing the gradations for each frame period. 
         FIG. 12F  is a table showing the gradations for each frame period. 
         FIG. 12G  is a table showing the gradations for each frame period. 
         FIG. 12H  is a table showing the gradations for each frame period. 
         FIG. 13  is a timing chart illustrating a driving method of a modified example. 
         FIG. 14  is a table showing gradations of the modified example. 
         FIG. 15  is a table showing the gradations of the modified example. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Embodiments will be described below with reference to the accompanying drawings. 
     First Exemplary Embodiment 
     Outline of Electronic Apparatus 
       FIG. 1  is a schematic diagram illustrating a configuration of a projector, which is an example of an electronic apparatus according to the present embodiment. Hereinafter, a configuration of a projector will be described with reference to  FIG. 1 . 
     As illustrated in  FIG. 1 , the projector  1000  at least includes three electro-optical devices  20  (see  FIG. 2 , hereinafter, also referred to as a first liquid crystal panel  201 , a second liquid crystal panel  202 , and a third liquid crystal panel  203 ), and a control device  30  that supplies control signals to the electro-optical devices  20 . 
     The first liquid crystal panel  201 , the second liquid crystal panel  202 , and the third liquid crystal panel  203  are three electro-optical devices  20  corresponding to different display colors (red, green, and blue). 
     An illumination optical system  1100  supplies red component R to the first liquid crystal panel  201 , green component G to the second liquid crystal panel  202 , and blue component B to the third liquid crystal panel  203  among light emitted from an illumination device (light source)  1200 . The first liquid crystal panel  201 , the second liquid crystal panel  202  and the third liquid crystal panel  203  function as light modulators (light valves) that modulate respective color lights supplied from the illumination optical system  1100  depending on a display image. A projection optical system  1300  combines the light emitted from the first liquid crystal panel  201 , the second liquid crystal panel  202 , and the third liquid crystal panel  203  and projects the combined light onto a projection surface  1400 . 
     Circuit Configuration of Electro-Optical Device 
       FIG. 2  is a block diagram illustrating a configuration of an electro-optical device. The configuration of the electro-optical device will be described below with reference to the block diagram illustrated in  FIG. 2 . 
     As illustrated in  FIG. 2 , the electro-optical device  20  at least includes a display region  42  and a driving unit  50 . In the display region  42 , a plurality of scanning lines  22  and a plurality of signal lines  23  which cross each other are formed, and pixels  21  are arranged in a matrix corresponding to each intersection of the scanning lines  22  and the signal lines  23 . 
     In the display region  42 , m scanning lines  22  (m is an integer not less than two) and n signal lines  23  (n is an integer not less than two) are formed. The scanning lines  22  extend in a row direction (X direction). The signal lines  23  extend in a column direction (Y direction). Note that, in the present embodiment, the electro-optical device  20  and the driving method of the electro-optical device  20  will be described with m=2168 and n=4112 as an example. In this case, a so-called 4K image of 2160 rows×4096 columns is displayed in the display region  42  of 2168 rows×4112 columns. 
     The driving unit  50  is configured to include a driving circuit  51  that drives each of the pixels  21 , a display signal supply circuit  32  that supplies a display signal to the driving circuit  51 , and a storage circuit  33  that temporarily stores the frame image. The driving circuit  51  is configured to include a scanning line driving circuit  52  and a signal line driving circuit  53 . Further, the driving unit  50  supplies a driving signal to the plurality of scanning lines  22  and the plurality of signal lines  23 . By supplying various signals from the driving unit  50 , an image is displayed in the display region  42 . 
     The display signal supply circuit  32  generates a display signal (such as an image signal and a clock signal) from a frame image stored in the storage circuit  33 . Furthermore the display signal supply circuit  32  supplies the generated display signal to the driving circuit  51 . 
     The display region  42  includes a first side (in the present embodiment, a left side of the display region  42 ), and a second side (in the present embodiment, a right side of the display region  42 ) opposed (substantially parallel) to the first side across the display region  42 . Further, the display region  42  includes a third side (in be present embodiment, a lower side of the display region  42 ) intersecting (substantially orthogonal) to the first side, and a fourth side opposed (substantially parallel) to the third side across the display region  42 . 
     The scanning line driving circuit  52  is formed along the first side, the second side, or the first side and the second side of the display region  42 . Although omitted in  FIG. 2  for clarity, in the present embodiment, as illustrated in  FIG. 4 , the scanning line driving circuit  52  is formed along the first side and the second side of the display region  42 . 
     The signal line driving circuit  53  is formed along the third side, the fourth side, or the third side and the fourth side of the display region  42 . In the present embodiment, the signal line driving circuit  53  is formed along the third side. Further, the signal line driving circuit  53  includes a selection signal output circuit  53   a  that outputs a selection signal to a switch SW to be described later, and an image signal output circuit  53   b  that outputs an image signal to the pixel  21 . 
     The scanning line driving circuit  52  outputs a scanning signal for selecting or non-selecting the pixel  21  in the row direction to each scanning line  22 . The scanning line  22  transmits the scanning signal to the pixel. Specifically, the scanning signal has a selected state and a non-selected state. The scanning line  22  can be appropriately selected by receiving the scanning signal from the scanning line driving circuit  52 . 
     The scanning line driving circuit  52  includes a shift register circuit (not illustrated). Specifically, a signal for shifting the shift register circuit is outputted as a shift output signal for each stage. The output signal is used to form a scanning signal. The signal line driving circuit  53  supplies an image signal to each of the n signal lines  23  in synchronization with the selection of the scanning lines  22 . 
     One display image is formed in one frame period. In one frame period, each scanning line  22  is selected at least once. Normally, each scanning line  22  is selected once. Since a period in which one scanning line is selected is referred to as a horizontal scanning period, at least m horizontal scanning periods are included in one frame period. The scanning line  22  is sequentially selected from the scanning line G 1  of the first row to the scanning line Gm of the m-th row (or, from the scanning line Gm of the m-th row to the scanning line G 1  of the first row) to configure one frame period, thus the frame period is also referred to as a vertical scanning period. 
     The electro-optical device  20  of the present embodiment is formed with a glass substrate (not illustrated). The driving circuit  51  is formed on a glass substrate with thin film elements such as thin film transistors. The control device  30  includes a display signal supply circuit  32  and a storage circuit  33 , and is configured of a semiconductor integrated circuit formed on a single crystal semiconductor substrate. 
     Beesides this configuration, the configuration also may be that the display region  42  is formed on a glass substrate, the driving circuit  51  is an integrated circuit formed on a single crystal semiconductor substrate, or both the display region  42  and the driving circuit  51  are formed on a single crystal semiconductor substrate. 
     Configuration of Pixel 
       FIG. 3  is a circuit diagram illustrating a configuration of a pixel configuring the electro-optical device. The configuration of the pixel will be described below with reference to  FIG. 3 . 
     The electro-optical device  20  of the present embodiment is, for example, a liquid crystal device. The electro-optical material is liquid crystal  26 . As illustrated in  FIG. 3 , each pixel  21  is configured to include a liquid crystal element LC and a pixel transistor  24 . 
     The liquid crystal element LC includes a pixel electrode  25  and a same electrode  27  facing each other. The liquid crystal element LC is an electro-optical element in which a liquid crystal  26  as an electro-optical material is arranged between the pixel electrode  25  and the same electrode  27 . Depending on the electric field applied between the pixel electrode  25  and the same electrode  27 , the transmittance of light passing through the liquid crystal  26  changes. 
     Note that, an electrophoretic material may be used as the electro-optical material rather than a liquid crystal  26 . In this case, the electro-optical device  20  serves as an electrophoresis device and is used in an electronic book or the like. 
     The pixel transistor  24  is configured of an N-type thin film transistor in which the gate is connected to the scanning line  22 . Further, the pixel transistor  24  is interposed between the pixel electrode  25  and the signal line  23  to control the electrical connections (conduction/non-conduction) of the two. 
     Accordingly, by the signal line driving circuit  53 , the pixel  21  (liquid crystal element LC) performs display according to the potential (image signal) supplied to the signal line  23  when the pixel transistor  24  is turned on. Note that the illustration of an auxiliary capacitance and the like connected in parallel to the liquid crystal element LC is omitted. 
     Circuit Configuration of Signal Line Driving Circuit 
       FIG. 4  is a circuit diagram illustrating a configuration of a signal line driving circuit. Hereinafter, a configuration of the signal line driving circuit will be described with reference to  FIG. 4 . 
     As illustrated in  FIG. 4 , the signal line driving circuit  53  is formed along the third side of the display region  42 . The signal line driving circuit  53  includes, for example, selection signal lines  100  from the first selection signal line  101  to the eighth selection signal line  108  to which selection signal SEL (first selection signal SEL 1  to eighth selection signal SEL 8 ) is supplied, and switches SW from the first switch SW 1  to the eighth switch SW 8 . 
     The signal line driving circuit  53  divides the signal line  23  that supplies the image signal D into k blocks (k is an integer not less than two), and by sequentially selecting n signal lines  23  (signal line group) in each block in one horizontal scanning period and supplying the image signal D, a writing time to the pixels  21  (pixels  21   a  to  21   h ) can be secured. Such a driving method is referred to as a demultiplexer driving method. 
     The number n of signal lines  23  is n=4112, for example. In the present embodiment, the first selection signal line  101  to the eighth selection signal line  108  is used, and thus the number j of image signal lines OSj is j=514 (4112/8SEL). In other words, the number n of signal lines  23  selected by the first selection signal SEL 1  is n=514. Similarly, the number n of signal lines selected by the second selection signal SEL 2  to the eighth selection signal. SEL 8  is n=514 respectively. 
     The first image signal line OS 1  is electrically coupled to the signal line  23  from the first signal line S 1  to the eighth signal line S 8 . Thereafter, similar circuit configurations are repeatedly formed from the second image signal line OS 2  to the j-th image signal line OSj. 
     Further, the signal line driving circuit  53  is provided with the first switch SW 1  to the eighth switch SW 8 . Similar to the pixel transistors  24 , the first switch SW 1  to the eighth switch SW 8  are formed of thin film ansistors. 
     The first switch SW 1  is arranged between the first signal line S 1  and the first image signal line OS 1 . One end (one of the source and the drain) of the first switch SW 1  is electrically coupled to the first signal line S 1 . The other end (the other of the source and the drain) of the first switch SW 1  is electrically coupled to the first image signal line OS 1 . The gate of the first switch SW 1  is electrically coupled to the first selection signal line  101 . 
     For example, when the first selection signal SEL 1  becomes a selection signal, the first switch SW 1  is turned on, and the first image signal D 1  is supplied to the first signal S 1 . When the second selection signal SEL 2  becomes a selection signal, the second switch SW 2  is turned on, and the second image signal D 2  is supplied to the second signal line S 2 . The image signal D is supplied to eight signal lines  23  by repeating similarly. 
     Note that in the present specification, for example, the wiring  1  and the wiring  2  are electrically coupled means that the wiring  1  and the wiring  2  can be in the same logic state (potential on the design concept). Specifically, in addition to the case where the wiring  1  and the wiring  2  are directly coupled, the ease where the wiring  1  and the wiring  2  are connected via low resistance, switching elements or the like are included. 
     That is, even when the potential at the wiring  1  and the potential at the wiring  2  are slightly different, when the same logic is given on the circuit, the wiring  1  and the wiring  2  are electrically coupled. Therefore, for example, as illustrated in  FIG. 4 , even when the first switch SW 1  is arranged between the first signal line S 1  and the first image signal line OS 1 , the first image signal D 1  is supplied to the first signal line S 1  when the first switch SW 1  is turned on, thus the first signal line S 1  and the first image signal line OS 1  are electrically coupled. 
     Driving Method for Electro-Optical Device 
       FIGS. 5A to 5H  are timing charts for illustrating a driving method for the electro-optical device according to First Exemplary Embodiment.  FIGS. 6A to 6H  are tables showing gradations for each frame period. Hereinafter, the driving method for the electro-optical device will be described below with reference to  FIGS. 5A to 5H  and  FIGS. 6A to 6H . 
     The timing chart illustrated in  FIG. 5A  illustrates a scanning signal (gate signal: GATE) supplied to the scanning line  22 , each of the selection signals SEL (the first selection signal SEL 1  to the eighth selection signal SEL 8 ), and image signal strain (VID) in the horizontal scanning period H in which the first scanning line G 1  is selected. The image signal strain (VID) includes a pre-charge signal PRC, an image signal D (the first image signal D 1  to the eighth image signal D 8 ), and a post charge signal PSTC. Note that, a circuit for supplying the pre-charge signal PRC and the post charge signal PSTC can use a known circuit, thus the illustration is omitted in  FIG. 4 . 
     Note that the pre-charge signal PRC is a signal performed in advance of writing to each of the pixels  21 . By performing the pre-charge operation, vertical crosstalk caused by the light leakage current of the pixel transistor  24  is suppressed. Further, the post charge signal PSTC is a signal that interpolates the pre-charge signal PRC. Description of the pre-charge signal PRC and the post charge signal PSTC will be omitted below. 
     Here, one vertical scanning period V (one frame period: one screen) includes m horizontal scanning periods Hm. For example, m is an integer of 1 to 2168. The timing chart illustrated in  FIG. 5A  illustrates the timing of each signal in one horizontal scanning period H. Note that in First Exemplary Embodiment, the same timing chart is used in the m horizontal scanning periods Hm. 
     As the driving method of First Exemplary Embodiment, a combination of the signal lines  23  that are simultaneously selected is changed for each frame period. For example, when the drive frequency is 60 Hz, one frame (one screen) is rewritten 60 times per second. That is, for each screen (each frame), the combination of the signal lines  23  that are simultaneously selected is changed. 
     Note that, the drive frequency S (S is a multiple of 60) of the present embodiment is 240 Hz (referred to as a four-time speed driving). In the case of the four-time speed driving, in the first frame period of  FIG. 5A  to the fourth frame of  FIG. 5D , display based on the first image signal for displaying the first image is repeatedly performed. Further, in the fifth frame of  FIG. 5E  to the eighth frame of  FIG. 5H , display based on the second image signal for displaying the second image is repeatedly displayed. 
     Note that the drive frequency S is not limited to 240 Hz, and may be 120 Hz (two-time speed driving), 180 Hz (three-time speed driving), 480 Hz (eight-time speed driving), and the like. Additionally, the drive frequency S is not limited to one-time speed driving, and may be 60 Hz. 
     As illustrated in  FIG. 5A , in the driving method according to First Exemplary Embodiment, the signal line driving circuit  53  supplies the pre-charge signal PRC to all of the signal lines  23 , and then supplies each of the image signals D. In the method for supplying each of the image signals D, first, during the horizontal scanning period H 1 , the first selection signal SEL 1  is supplied to the first selection signal line  101  to turn on the first switch SW 1 , and the first signal line S 1  is selected (see  FIG. 4 ). Then, the first image signal D 1  is supplied to the selected first signal line S 1  via the first image signal line OS 1 . Accordingly, the first image signal D 1  is written to the first pixel  21   a  in the first row (corresponding to the first scanning line G 1 ). 
     Next, the signal line driving circuit  53  supplies the second selection signal SEL 2  to the second selection signal line  102  to turn on the second switch SW 2  and to select the second signal line S 2 . Then, the second image signal D 2  is supplied to the selected second signal line S 2  via the first image signal line OS 1 . Accordingly, the second image signal D 2  is written to the second pixel  21   b  in the first row. 
     Next, the signal line driving circuit  53  supplies the third selection signal SEL 3  to the third selection signal line  103  to turn on the third switch SW 3  and to select the third signal line S 3 . Then, the third image signal D 3  is supplied to the selected third signal line S 3  via the first image signal line OS 1 . Accordingly, the third image signal D 3  is written to the third pixel  21   c  in the first row. 
     Next, the signal line driving circuit  53  supplies the fourth selection signal SEL 4  to the fourth selection signal line  104  to turn on the fourth switch SW 4  and to select the fourth signal line S 4 . Then, the fourth image signal D 4  is supplied to the selected fourth signal line S 4  via the first image signal line OS 1 . Accordingly, the fourth image signal D 4  is written to the fourth pixel  21   d  in the first row. 
     Next, the signal line driving circuit  53  supplies the fifth selection signal SEL 5  to the fifth selection signal line  105  to turn on the fifth switch SW 5  and to select the fifth signal line S 5 . Then, the fifth image signal D 5  is supplied to the selected fifth signal line S 5  via the first image signal line OS 1 . Accordingly, the fifth image signal D 5  is written to the fifth pixel  21   e  in the first row. 
     Next, the signal line driving circuit  53  supplies the sixth selection signal SEL 6  to the sixth selection signal line  106  to turn on the sixth switch SW 6  and to select the sixth signal line S 6 . Then, the sixth image signal D 6  is supplied to the selected sixth signal line S 6  via the first image signal line OS 1 . Accordingly, the sixth image signal D 6  is written to the sixth pixel  21   f  in the first row. 
     Next, the signal line driving circuit  53  supplies the seventh selection signal SEL 7  to the seventh selection signal line  107 , and supplies the eighth selection signal SEL 8  to the eighth selection signal line  108 , to simultaneously turn on the seventh switch SW 7  and the eighth switch SW and to simultaneously select the seventh signal line S 7  and the eighth signal line S 8 . Then, the seventh image signal D 7 , which is the same image signal D, for example, is supplied to the seventh signal line S 7  and the eighth signal line S 8  that are selected. Accordingly, the seventh image signal D 7 , which is the same as image signal D, is written to the seventh pixel  21   g  and the eighth pixel  21   h  in the first row. 
     Note that, the same image signal D supplied to the seventh signal line S 7  and the eighth signal line S 8  is not limited to one of the seventh image signal D 7 , and may supply the other one of the eighth image signal D 8 . Further, the image signal D obtained by averaging the image signal D to be supplied to the two signal lines be supplied. 
     Then, the second scanning line G 2  is selected, in the horizontal scanning period H of the selected second scanning line G 2  (second horizontal scanning period H 2 ), the image signal D is written to the pixels  21  in the second row (corresponding to the second scanning line G 2 ) using the same driving method as described above. 
     Thereafter, the same driving is performed to the scanning line Gm in the m-th row, and the writing operation for the first frame period (first vertical scanning period V 1 ) is completed. 
     In this manner, by simultaneously selecting two adjacent signal lines  23  (the seventh signal line S 7  and the eighth signal line S 8 ) and supplying seventh image signal D 7  to the both, as compared to the case where one signal line  23  is selected to supply the image signal D, the selected period can be shortened by one period. That is, the writing period to the pixels  21  can be shortened, thus the writing period to the pixels  21  can be easily secured within the limited horizontal scanning period H. Further, the horizontal scanning period H can be shortened, thus, it is possible to easily accommodate high resolution and high speed driving by increasing the drive frequency. 
       FIG. 6A  shows a gradation distribution (gradation image) of the display region  42  of a part of the first frame period when driven by the driving method described above. Specifically, it is displayed in 8-bit (0 to 255) gradation. 
     For example, as described above, in the first scanning line G 1  of the first row, the first signal line S 1  is selected by the first selection signal SEL 1 , the first image signal D 1  is supplied to the first signal line S 1 , and a gradation of the first pixel  21   a  when the first image signal D 1  is written to the first pixel  21   a  is 80 gradations (portion a). 
     Further, for example, the second signal line S 2  is selected by the second selection signal SEL 2 , the second image signal D 2  is supplied to the second signal line S 2 , and a gradation of the second pixel  21   b  when the second image signal D 2  is written to the second pixel  21   b  is 100 gradations (portion b). 
     In other words, the first pixel  21   a  corresponds to the first selection signal SEL 1 , and the second pixel  21   b  corresponds to the second selection signal SEL 2 . On the other hand, the first scanning line G 1  corresponds to the first horizontal scanning period H 1 , and the second scanning line G 2  corresponds to the second horizontal scanning period H 2 . 
     That is, the table in  FIG. 6A  shows gradations of eight horizontal scanning periods H (H 1  to H 8 ) when the first signal line S 1  to the eighth signal line S 8  that are selected by the first selection signal SEL 1  to the eighth selection signal SEL 8  are supplied with the first image signal D 1  to the eighth image signal D 8  via the first image signal line OS 1 . 
     During the first frame period displayed by the driving method according to First Exemplary Embodiment, the adjacent seventh signal line S 7  and eighth signal line S 8  are simultaneously selected, and a same image signal D (seventh image signal D 7 ) is written to the seventh pixel  21   g  and the eighth pixel  21   h , thus the gradations of the pixel column of the seventh pixel  21   g  and the pixel column of the eighth pixel  21   h  are both 200 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     Further, in this way, the same image signal D is supplied to the adjacent pixels  21 , thus, deterioration of the display image can be suppressed without greatly differing the gradation. Hereinafter, in description of the driving method in the second frame period to the eighth frame period (each vertical scanning period V), and description of the gradations in each frame period, only the characteristic parts will be mainly described. 
     As illustrated in  FIG. 5B , the driving method of the second frame period (second vertical scanning period V 2 ) is to supply the sixth selection signal SEL 6  to the sixth selection signal line  106  and the seventh selection signal SEL 7  to the seventh selection signal line  107 , and to simultaneously select the sixth signal line S 6  and the seventh signal line S 7 . Then, the sixth image signal D 6 , which is the same image signal D, for example, is supplied to the selected sixth signal line S 6  and seventh signal S 7 . As described above, the image signal D to be supplied is not limited to the sixth image signal D 6 , and may be the seventh image signal D 7 . Hereinafter, in the second frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 6B , the gradation distribution of the second frame period is such that, both the gradations of the sixth pixel  21   f  to which the sixth image signal D 6  are written from the sixth signal line S 6 , and the gradations of the seventh pixel  21   g  to which the sixth image signal D 6  are written from the seventh signal line S 7 , become 180 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     Also in this case, similar to the first frame period, the selecting period can be shortened by one period, and the same image signal D is supplied to the two adjacent signal lines  23 , thus, the gradation distribution does not change greatly around the periphery, and deterioration of the image can be suppressed. 
     Furthermore, as compared to the first frame period, the simultaneously selected pixels  21  are shifted adjacent (left side in the present embodiment), thus, a same gradation region can be dispersed without concentration of a same gradation on a part of the display screen, and deterioration of the display image can be suppressed. That is, by suppressing the generation of vertical stripes due to the same gradation on a part of the display screen being repeatedly displayed from the first frame period to the second frame period, and the deterioration of the resolution due to the same image signal D (seventh image signal D 7 ) being written to the seventh pixel  21   g  and the eighth pixel  21   h , it is possible to provide an electro-optical device and a driving method for the electro-optical device that can accommodate high resolution and high speed driving while suppressing deterioration of image quality. 
     As illustrated in  FIG. 5C , the driving method of the third frame period (third vertical scanning period V 3 ) is to supply the fifth selection signal SEL 5  to the fifth selection signal line  105  and the sixth selection signal SEL 6  to the sixth selection signal line  106 , and to simultaneously select the fifth signal line S 5  and the sixth signal line S 6 . Then, the fifth image signal D 5 , which is the same image signal D, for example, is supplied to the selected fifth signal line S 5  and sixth signal line S 6 . Hereinafter, in the third frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 6C , the gradation distribution of the third frame period is such that, both the gradations of the fifth pixel  21   e  to which the fifth image signal D 5  are written from the fifth signal line S 5 , and the gradations of the sixth pixel  21   f  to which the fifth image signal D 5  are written from the sixth signal line D 5 , become 160 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     As illustrated in  FIG. 5D , the driving method of the fourth frame period (fourth vertical scanning period V 4 ) is to supply the fourth selection signal SEL 4  to the fourth selection signal line  104  and the fifth selection signal SEL 5  to the fifth selection signal line  105 , and to simultaneously select the fourth signal line S 4  and the fifth signal S 5 . Then, the fourth image signal D 4 , which is the same image signal D, for example, is supplied to the selected fourth signal line S 4  and fifth signal line S 5 . Hereinafter, in the fourth frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 6D , the gradation distribution of the fourth frame period is such that, both the gradations of the fourth pixel  21   e  to which the fourth image signal D 4  are written from the fourth signal line S 4 , and the gradations of the fifth pixel  21   e  to which the fourth image signal D 4  are written from the fifth signal line S 5 , become 140 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     In this way, the simultaneously selected pixels  21  are shifted in the adjacent direction (left side in the present embodiment) from the first frame period to the fourth frame period, thus, a same gradation region can be dispersed without the concentration of a same gradation on a part of the display screen, and deterioration of the display image can be suppressed. That is, by suppressing the generation of vertical stripes due to the same gradation on a part of the display screen being repeatedly displayed from the first frame period to the fourth frame period, and the deterioration of the resolution due to the same image signal D (seventh image signal D 7 ) being written to the seventh pixel  21   g  and the eighth pixel  21   h , it is possible to provide an electro-optical device and a driving method for the electro-optical device that can accommodate high resolution and high speed driving while suppressing deterioration of image quality. 
     As illustrated in  FIG. 5E , the driving method of the fifth frame period (fifth vertical scanning period V 5 ) is to supply the third selection signal SEL 3  to the third selection signal line  103  and the fourth selection signal SEL 4  to the fourth selection signal line  104 , and to simultaneously select the third signal line S 3  and the fourth signal line S 4 . Then, the third image signal D 3 , which is the same image signal D, for example, is supplied to the selected third signal line S 3  and the fourth signal line S 4 . Hereinafter, in the fifth frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 6E , the gradation distribution of the fifth frame period is such that, both the gradations of the third pixel  21   c  to which the third image signal D 3  are written from the third signal line S 3 , and the gradations of the fourth pixel  21   d  to which the third image signal D 3  are written from the fourth signal line S 4 , become 120 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     As illustrated in  FIG. 5F , the driving method of the sixth frame period (sixth vertical scanning period V 6 ) is to supply the second selection signal SEL 2  to the second selection signal line  102  and the third selection signal SEL 3  to the third selection signal line  103 , and to simultaneously select the second signal line S 2  and the third signal line S 3 . Then, the second image signal D 2 , which is the same image signal D, for example, is supplied to the selected second signal line S 2  and the third signal line S 3 . Hereinafter, in the sixth frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 6F , the gradation distribution of the sixth frame period is such that, both the gradations of the second pixel  21   b  to which the second image signal D 2  are written from the second signal line D 2 , and the gradations of the third pixel  21   c  to which the second image signal D 2  are written from the third signal line S 3 , become 100 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     As illustrated in  FIG. 5G , the driving method of the seventh frame period (seventh vertical scanning period V 7 ) is to supply the first selection signal SEL 1  to the first selection signal line  101  and the second selection signal SEL 2  to the second selection signal line  102 , and to simultaneously select the first signal line S 1  and the second signal line S 2 . Then, the first image signal D 1 , which is the same image signal D, for example, is supplied to the selected first signal line S 1  and the second signal line S 2 . Hereinafter, in the seventh frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 6G , the gradation distribution of the seventh frame period is such that, both the gradations of the first pixel  21   a  to which the first image signal D 1  are written from the first signal line S 1 , and the gradations of the second pixel  21   b  to which the first image signal D 1  are written from the second signal line S 2 , become 80 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     As illustrated in  FIG. 5H , in the driving method of the eighth frame period (eighth vertical scanning period V 8 ) is to supply the eighth selection signal SEL 8  to the eighth selection signal line  108  and the first selection signal SEL 1  to the first selection signal line  101 , and to simultaneously select the eighth signal line S 8  and the first signal line S 1 . 
     Note that, the eighth signal line S 8  described here is a signal line adjacent to the first signal line S 1 , thus refers to the eighth signal line S 8  of the block of the adjacent signal lines. Specifically, for example, the eighth signal line S 8  may be electrically coupled to the 0th image signal line OS 0  arranged adjacent to the first image signal line OS 1 . 
     Then, the eighth image signal D 8 , which is the same image signal D, for example, is supplied to the selected eighth signal line S 8  and first signal line S 1 . Hereinafter, in the eighth frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 6H , the gradation distribution of the eighth frame period is such that, both the gradations of the eighth pixel  21   h  to which the eighth image signal D 8  are written from the eighth signal line S 8 , and the gradations of the first pixel  21   a  to which the eighth image signal D 8  are written from the first signal line S 1 , become 60 gradations. 
     Note that, in the gradation distribution shown in  FIG. 6H , although the gradation of the eighth pixel  21   h  electrically coupled to the 0th image signal line OS 0  adjacent to the first image signal line OS 1  is not displayed, it is 60 gradations. Hereinafter, in the eighth frame period, each horizontal scanning period H is driven in the same manner. 
     In this way, the simultaneously selected pixels  21  are shifted in the adjacent direction (left side in the present embodiment) from the fifth frame period to the eighth frame period, thus, a same gradation region can be dispersed without concentration of a same gradation on a part of the display screen, and deterioration of the display image can be suppressed. That is, by suppressing the generation of vertical stripes due to the same gradation on a part display screen being repeatedly displayed from the first frame period to the fourth frame period, and the deterioration of the resolution due to the same image signal D (third image signal D 3 ) being written to the third pixel  21   c  and the fourth pixel  21   d , it is possible to provide a driving method that can accommodate high resolution and high speed driving while suppressing deterioration of image quality. 
     As described above, according to the electro-optical device  20 , the driving method for the electro-optical device  20  and the electronic apparatus according to the First Exemplary Embodiment, the following effects can be obtained. 
     (1) According to First Exemplary Embodiment, the two adjacent signal lines  23  are simultaneously selected to supply the same image signal D, thus, as compared to a case where one signal line  23  is selected to supply the image signal D, the selecting period (time) can be shortened by one period. In addition, the same image signal D is written to adjacent pixels coupled to the two adjacent signal lines  23 , thus the gradation difference between the adjacent pixels  21  can be reduced, and deterioration of the display image can be suppressed. As a result, the time of writing the image signal D to the signal line  23  can be secured, and high-resolution display quality can be provided. Specifically, for example, brightness and image quality can be improved by increasing the writing time as much as reducing the number of times of writing. Furthermore, by increasing the drive frequency as much as reducing the number of times of writing, it is possible to easily achieve high resolution and high speed driving. 
     (2) According to First Exemplary Embodiment, the combination of the signal lines  23  to which the same image signal D is supplied is changed for each frame period, the position of the pixels  21  having the same gradation can be shifted. Specifically, the position of adjacent pixels  21  performing the same gradation display are not fixed in the display region  42 , thus deterioration of image quality can be suppressed. 
     Second Exemplary Embodiment 
     Driving Method for Electro-Optical Device 
       FIG. 7A  to  FIG. 7D  are timing charts illustrating a driving method for an electro-optical device according to Second Exemplary Embodiment.  FIGS. 8A to 8D  are tables showing gradations for each frame period. A driving method for the electro-optical device according to Second Exemplary Embodiment will be described below with reference to  FIGS. 7A to 7D  and  FIGS. 8A to 8D . 
     In the driving method of First Exemplary Embodiment described above, in the demultiplexer circuit, one set of two adjacent signal lines  23  is selected, and the same image signal D is supplied to the two selected signal lines  23 . In contrast, the driving method of Second Exemplary Embodiment differs in that, in the demultiplexer circuit, portions where two sets of two adjacent signal lines  23  are selected. The other portions are substantially the same as those of First Exemplary Embodiment, and therefore, in Second Embodiment, portions different from those of First Exemplary Embodiment will be described in detail, and descriptions of other overlapping portions be omitted as appropriate. Note that in Second Exemplary Embodiment, the drive frequency S (S is a multiple of 60) is 240 Hz (four-time speed driving). 
     As described above, in the driving method of Second Exemplary Embodiment, the combination of the simultaneously selected signal lines  23  is set in two sets. Specifically, as illustrated in  FIG. 7A , in the first frame period (first vertical scanning period V 1 ), the third selection signal SEL 3  is supplied to the third selection signal line  103 , the fourth selection signal SEL 4  is supplied to the fourth selection signal line  104 , and the third signal line S 3  and the fourth signal line S 4  (first signal line group) are simultaneously selected. 
     Then, the third image signal D 3  (first image signal), which is the same image signal D, for example, is supplied to the simultaneously third selected signal line S 3  and the fourth signal line S 4 . This is the combination of a first set of signal lines  23 . Next, a combination of a second set of signal lines  23  will be described. 
     In the second set, similar in the first frame period, the seventh selection signal SEL 7  is supplied to the seventh selection signal line  107 , the eighth selection signal SEL 8  is supplied to the eighth selection signal line  108 , and the seventh signal line S 7  and the eighth signal line S 8  (second signal line group) are simultaneously selected. Then, the seventh image signal D 7  (second image signal), which is the same image signal D, for example, is supplied to the simultaneously selected seventh signal line S 7  and the eighth signal line S 8 . 
     In this way, the third image signal D 3  is written to both the third pixel  21   c  and the fourth pixel  21   d . On the other hand, the seventh image signal D 7  is written to both the seventh pixel  21   g  and the eighth pixel  21   h . Hereinafter, in the first frame period, each horizontal scanning period H is driven in the same manner. 
     As described above, by configuring the combination of the simultaneously selected two signal lines  23  into two sets, the selecting period can be shortened by two periods as compared with First Exemplary Embodiment. As a result, the writing time to the pixel  21  can be further secured. Accordingly, it is possible to suppress the influence of leakage current, and to improve the brightness. 
     As shown in  FIG. 8A , the gradation distribution of the first frame period is such that, both the gradations of the third pixel  21   c  to which the third image signal D 3  are written from the third signal line S 3 , and the gradations of the fourth pixel  21   d  to which the third image signal D 3  are written from the fourth signal line S 4 , become 120 gradations. 
     In addition, both the gradations of the seventh pixel  21   g  to which the seventh image signal D 7  are written from the seventh signal line S 7 , and the gradations of the eighth pixel  21   h  to which the seventh image signal D 7  are written from the eighth signal line S 8 , become 200 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     As illustrated in  FIG. 7B , the driving method for the second frame period (second vertical scanning period V 2 ) is to supply the second selection signal SEL 2  to the second selection signal line  102  and the third selection signal SEL 3  to the third selection signal line  103 , and to simultaneously select the second signal line S 2  and the third signal line S 3 . Then, the second image signal D 2 , which is the same image signal D, for example, is supplied to the selected second signal line S 2  and the third signal line S 3 . 
     Further, the sixth selection signal SEL 6  is supplied to the sixth selection signal lint  106 , the seventh selection signal SEL 7  is supplied to the seventh selection signal line  107 , and the sixth signal line S 6  and the seventh signal line S 7  are simultaneously selected. Then, the sixth image signal D 6 , which is the same image signal D, for example, is supplied to the selected sixth signal line S 6  and seventh signal line S 7 . Hereinafter, in the second frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 8B , the gradation distribution of the second frame period is such that, both the gradations of the second pixel  21   b  to which the second image signal D 2  are written from the second signal line S 2 , and the gradations of the third pixel  21   c  to which the second image signal D 2  are written from the third signal line S 3 , become 100 gradations. 
     In addition, both the gradations of the sixth pixel  21   f  to which the sixth image signal D 6  are written from the sixth signal line S 6 , and the gradations of the seventh pixel  21   g  to which the sixth image signal D 6  are written the seventh signal line S 7 , become 180 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     As illustrated in  FIG. 7C , the driving method of the third frame period (third vertical scanning period V 3 ) is to supply the first selection signal SEL 1  to the first selection signal line  101  and the second selection signal SEL 2  to the second selection signal line  102 , and to simultaneously select the first signal line S 1  and the second signal line S 2 . Then, the first image signal D 1 , which is the same image signal D, for example, is supplied to the selected first signal line S 1  and the second signal line S 2 . 
     In addition, the fifth selection signal SEL 5  is supplied to the fifth selection signal line  105 , the sixth selection signal SEL 6  is supplied to the sixth selection signal line  106 , and the fifth signal line S 5  and the sixth signal line S 6  are simultaneously selected. Then, the fifth image signal D 5 , which is the same image signal D, for example, is supplied to the simultaneously selected fifth signal line S 5  and sixth signal line S 6 . Hereinafter, in the third frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 8C , the gradation distribution for the third frame period is such that, both the gradations of the first pixel  21   a  to which the first image signal D 1  are written from the first signal line S 1 , and the gradations of the second pixel  21   b  to which the first image signal D 1  are written from the second signal line S 2 , become 80 gradations. 
     In addition, both the gradations of the fifth pixel  21   e  to which the fifth image signal D 5  are written from the fifth signal line S 5 , and the gradations of the sixth pixel  21   f  to which the fifth image signal D 5  are written from the sixth signal line S 6 , become 160 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     As illustrated in  FIG. 7D , the driving method for the fourth frame period (fourth vertical scanning period V 4 ) is to supply the eighth selection signal SEL 8  to the eighth selection signal line  108  and the first selection signal SEL 1  to the first selection signal line  101 , and to simultaneously select the eighth signal line S 8  and the first signal line S 1 . Then, the eighth image signal D 8 , which is the same image signal D, for example, is supplied to the selected eighth signal line S 8  and first signal line S 1 . Note that the eighth signal line S 8  is electrically coupled to the 0th image signal line OS 0 . 
     Furthermore, the fourth selection signal SEL 4  is supplied to the fourth selection signal line  104 , the fifth selection signal SEL 5  is supplied to the fifth selection signal line  105 , and the fourth signal line S 4  and the fifth signal line S 5  are simultaneously selected. Then, the fourth image signal D 4 , which is the same image signal D, for example, is supplied to the simultaneously selected fourth signal line S 4  and the fifth signal line S 5 . Hereinafter, in the fourth frame period, each horizontal scanning period H is driven in the same manner. 
     As shown in  FIG. 8D , the gradation distribution of the fourth frame period is such that, both the gradations of the eighth pixel  21   h  to which the eighth image signal D 8  are written from the eighth signal line S 8  and the gradations of the first pixel  21   a  to which the eighth image signal D 8  are written from the first signal line S 1  become 60 gradations (the illustration of 60 gradations of the eighth pixel  21   h  is omitted). 
     In addition, both the gradations of the fourth pixel  21   d  to which the fourth image signal D 4  are written from the fourth signal line S 4  and the gradations of the fifth pixel  21   e  to which the fourth image signal D 4  are written from the fifth signal line S 4  become 140 gradations. Hereinafter, the same gradation display in the column direction (H 1  to H 8 ) of the display region  42  is shown by being driven in the same manner. 
     As described above, according to the driving method of the electro-optical device  20  of Second Exemplary Embodiment, the following effects can be obtained. 
     (3) According to Second Exemplary Embodiment, the two signal lines  23  of the first set are simultaneously selected to supply the same image signal D, and the two signal lines  23  of the second set are simultaneously selected to supply the same image signal D, thus the selecting period can be shortened by two periods. Therefore, the writing period to the pixels  21  can be shortened, thus the writing period to the pixels  21  can be easily secured within the limited horizontal scanning period H. Further, the horizontal scanning period H can be shortened, thus, it is possible to easily accommodate high resolution and high speed driving by increasing the drive frequency. Further, the simultaneously selected pixels  21  are shifted adjacent (left side in the present embodiment) from the first frame period to the fourth frame period, thus, a same gradation region can be dispersed without concentration of a same gradation on a part of the display screen, and deterioration of the display image can be suppressed. That is, by suppressing the generation of the vertical stripes due to the same gradation on a part of the display screen being repeatedly displayed from the first frame period to the fourth frame period, and the deterioration of resolution due to the same image signal D (the third image signal D 3  and the seventh image signal D 7 ) being written to the third pixel  21   c  and the fourth pixel  21   d , and the seventh pixel  21   g  and the eighth pixel  21   h , respectively, it is possible to provide an electro-optical device and a driving method for the electro-optical device that can accommodate high resolution and high speed driving while suppressing deterioration of image quality. 
     Third Exemplary Embodiment 
     Driving Method for Electro-Optical Device 
       FIG. 9  is a timing chart illustrating a driving method for an electro-optical device according to Third Exemplary Embodiment.  FIGS. 10A to 10D  are tables showing gradations for each frame period. A driving method for the electro-optical device according to Third Exemplary Embodiment will be described below with reference to  FIG. 9  and  FIGS. 10A to 10D . 
     In the driving method according to Second Exemplary Embodiment described above, in the demultiplexer circuit, two sets of the two adjacent signal lines  23  are selected, and further, the signal lines  23  that combine in each frame period from the first frame period to the fourth frame period and from the fifth frame period to the eighth frame period are changed. In contrast, the driving method of Third Exemplary Embodiment differs in that, in the demultiplexer circuit, in addition to the driving method of Second Exemplary Embodiment, the portions where the combination of the simultaneously selected signal lines  23  for each horizontal scanning period H configuring one frame period is changed. In other words, the combination of simultaneously selected signal lines is rotated within one frame period. In this way, the combination of signal lines  23  that are simultaneously selected for each horizontal scanning period H is changed, thus deterioration of the image in one frame can be suppressed without generating the vertical stripes. The other portions are substantially the same as those of Second Exemplary Embodiment, and therefore, in Third Exemplary Embodiment, portions different from those of Second Exemplary Embodiment will be described in detail, and descriptions of other overlapping portions will be omitted as appropriate. 
     In the driving method of Third Exemplary Embodiment, as described above, the simultaneously selected signal lines  23  is changed for each horizontal scanning period H (first horizontal scanning period H 1 , second horizontal scanning period H 2 , third horizontal scanning period H 3 , and fourth horizontal scanning period H 4 ) which configures the frazzle period. Specifically, as illustrated  FIG. 9 , in the first horizontal scanning period H 1  of the first frame period, the third signal line S 3  and the fourth signal line S 4  are simultaneously selected, and the same third image signal D 3  is supplied to both the third signal S 3  and the fourth signal line S 4 . 
     Further, in the same first horizontal scanning period H 1 , the seventh signal line S 7  and the eighth signal line S 8  are simultaneously selected, and the same seventh image signal D 7  is supplied to both the selected seventh signal line S 7  and the eighth signal line S 8 . 
     As shown in  FIG. 10A , the gradation distribution of the first horizontal scanning period H 1  is such that, both the gradations of the third pixel  21   c  to which the third image signal D 3  are written from the third signal line S 3  and the gradations of the fourth pixel  21   d  to which the third image signal D 3  are written from the fourth signal line S 4  become 120 gradations. 
     In addition, both the gradations of the seventh pixel  21   g  to which the seventh image signal D 7  are written from the seventh signal line S 7 , and the gradations of the eighth pixel  21   h  to which the seventh image signal D 7  are written from the eighth signal line S 8 , become 200 gradations. 
     Next, as illustrated in  FIG. 9 , in the second horizontal scanning period H 2  of the first frame period, the second signal line S 2  and the third signal line S 3  are simultaneously selected, and the same second image signal D 2  is supplied to both the selected second signal line S 2  and the third signal line S 3 . 
     Further, in the second horizontal scanning period H 2 , the sixth signal line S 6  and the seventh signal line S 7  are simultaneously selected, and the same sixth image signal D 6  is supplied to both the selected sixth signal line S 6  and the seventh signal line S 7 . 
     As shown in  FIG. 10A , the gradation distribution of the second horizontal scanning period H 2  is such that, both the gradations of the second pixel  21   b  to which the second image signal D 2  are written via the second signal line S 2  and the gradations of the third pixel  21   c  to which the second image signal D 2  are written via the third signal line S 3  become 100 gradations. 
     Further, both the gradations of the sixth pixel  21   f  to which the sixth image signal D 6  are written via the sixth signal line S 6  and the gradations of the seventh pixel  21   g  to which the sixth image signal D 6  are written via the seventh signal line S 7  become 180 gradations. 
     Next, as illustrated in  FIG. 9 , in the third horizontal scanning period H 3  of the first frame period, the first signal line S 1  and the second signal line S 2  are simultaneously selected, and the same first image signal D is supplied to both the selected first signal line S 1  and the second signal line S 2 . 
     In addition, in the third horizontal scanning period H 3 , the fifth signal line S 5  and the sixth signal line S 6  are simultaneously selected, and the same fifth image signal D 5  is supplied to both the selected fifth signal line S 5  and sixth signal line S 6 . 
     As shown in  FIG. 10A , the gradation distribution of the third horizontal scanning period H 3  is such that, both the gradations of the first pixel  21   a  to which the first image signal D 1  are written via the first signal line S 1  and the gradations of the second pixel  21   b  to which the first image signal D 1  are written via the second signal line S 2 , become 80 gradations. 
     In addition, both the gradations of the fifth pixel  21   e  to which the fifth image signal D 5  are written via the fifth signal line S 5  and the gradations of the sixth pixel  21   f  to which the fifth image signal D 5  are written via the sixth signal line S 6  become 160 gradations. 
     Next, as illustrated in  FIG. 9 , in the fourth horizontal scanning period H 4  in the first frame period, the eighth signal line S 8  and the first signal line S 1  are selected, and the same eighth image signal D 8  is supplied to both the selected eighth signal line S 8  and the first signal line S 1 . 
     Note that, the eighth signal line S 8  described here is a signal line adjacent to the first signal line S 1 , thus refers to the eighth signal line S 8  of the block of the adjacent signal lines. Specifically, for example, the eighth signal line S 8  may be electrically coupled to the 0th image signal line OS 0  adjacent to the first image signal line OS 1 . 
     Further, in the fourth horizontal scanning period H 4 , the fourth signal line S 4  and the fifth signal line S 5  are simultaneously selected, and the same fourth age signal D 4  is supplied to both the selected fourth signal line S 4  and the fifth signal line S 5 . 
     As shown in  FIG. 10A , the gradation distribution of the fourth horizontal scanning period H 4  is such that, both the gradations (not illustrated) of the eighth pixel  21   h  to which the eighth image signal D 8  are written via the eighth signal line S 8 , and the gradations of the first pixel  21   a  to which the eighth image signal D 8  are written via the first signal line S 1 , become 60 gradations. 
     In addition, both the gradations of the fourth pixel  21   d  to which the fourth image signal D 4  are written via the fourth signal line S 4  and the gradations of the fifth pixel  21   e  to which the fourth image signal D 4  are written via the fifth signal line S 4  become 140 gradations. 
     Hereinafter, the same driving is repeated from the first horizontal scanning period H 1  to the fourth horizontal scanning period H 4  as described above, and the writing of the image signal D to all of the pixels  21  in the first frame period is completed. 
     In this way, the two adjacent signal lines  23  supplying the same image signal D are made into two sets, and the combination of the two signal lines  23  is changed for each horizontal scanning period H, thus, the positions of adjacent pixels  21  having the same gradation can be dispersed among the screen of one frame. Thus, it is possible to make the deterioration of image quality difficult to be visually recognizable. 
     Next, a driving method of the second frame period will be described with reference to  FIG. 9  and  FIG. 10B . As shown in  FIG. 10B , the driving method of the second frame period starts in a drive mode of the second horizontal scanning period H 2 . Hereinafter, driving is performed in an order of a drive mode of the third horizontal scanning period H 3 , a drive mode of the fourth horizontal scanning period H 4 , and a drive mode of the first horizontal scanning period H 1 . Hereinafter, driving is performed in the same order of drive modes, and writing of the image signal D to all of the pixels  21  in the second frame period is completed. The gradation distribution of the second frame period is shown in the table of  FIG. 10B . 
     Next, a driving method of the third frame period will be described. As shown in  FIG. 10C , the driving method of the third frame period starts in the drive mode of the third horizontal scanning period H 3 . Hereinafter, driving is performed in an order of the drive mode of the fourth horizontal scanning period H 4 , the drive mode of the first horizontal scanning period H 1 , and the drive mode of the second horizontal scanning period H 2 , and the writing of the image signal D to all of the pixels  21  in the third frame period is completed. The gradation distribution of the third frame period is shown in the table of  FIG. 10C . 
     Next, a driving method of the fourth frame period will be described. As shown in  FIG. 10D , the driving method of the fourth frame period starts in the drive mode of the fourth horizontal scanning period H 4 . Hereinafter, driving is performed in an order of the drive mode of the first horizontal scanning period H 1 , the drive mode of the second horizontal scanning period H 2 , and the drive mode of the third horizontal scanning period H 3 , and the writing of the image signal D to all of the pixels  21  in the fourth frame period is completed. The gradation distribution of the fourth frame period is shown in the table of  FIG. 10D . 
     As such, by changing the order of the drive modes in each frame period, the positions of adjacent pixels  21  having the same gradation adjacent to each other in each frame can be dispersed. Thus, it is possible to make the deterioration of image quality difficult to be visually recognized. 
     As described above, according to the driving method of the electro-optical device  20  of the Third Exemplary Embodiment, the following effects can be obtained. 
     (4) According to the Third Exemplary Embodiment, the combination of the two adjacent signal lines  23  simultaneously selected in each horizontal scanning period H is changed, thus, in one frame (one screen), the positions of the pixels  21  having the same gradation can be shifted in the column direction, and it is possible to make the deterioration of image quality difficult to be visually recognized. Furthermore, the two signal lines  23  simultaneously selected are rotated within one frame period. In this way, the combination of signal lines  23  that are simultaneously selected in each horizontal scanning period H is changed, thus deterioration of the image for one frame period can be suppressed without generating the vertical stripes. Further, the combination of the simultaneously selected two adjacent signal lines  23  is changed in each frame period, thus the positions of the pixels  21  having the same gradation can be shifted in the row direction, and it is possible to make the deterioration of image quality difficult to be recognized. 
     Fourth Exemplary Embodiment 
     Driving Method for Electro-Optical Device 
       FIG. 11  is a timing chart illustrating driving method for an electro-optical device according to Fourth Exemplary Embodiment.  FIGS. 12A to 12H  are tables showing gradations for each frame period. A driving method for the electro-optical device according to Fourth Exemplary Embodiment will be described below with reference to  FIG. 11  and  FIGS. 12A to 12H . 
     In the driving method according to Third Exemplary Embodiment described above, in the demultiplexer circuit, two sets of the two adjacent signal lines  23  are selected, and further, the combination of the signal lines  23  simultaneously selected in each horizontal scanning period H and each frame period is changed. In contrast, the driving method of Fourth Exemplary Embodiment differs in that, in the demultiplexer circuit, portions where the timing of the selection signal SEL supplied to each of the selection signal lines  100  for each horizontal scanning period H is changed. The other portions are substantially the same as those of Third Exemplary Embodiment, and thus, in Fourth Exemplary Embodiment, portions different from those of Third Exemplary Embodiment will be described in detail, and descriptions of other overlapping portions will be omitted as appropriate. 
     As described above, in the driving method according to Fourth Exemplary Embodiment, the supply order of each selection signal SEL is changed for each horizontal scanning period H. Specifically, the supply is not constantly started from the first selection signal SEL 1 , but the supply may be started from the second selection signal SEL 2 , or started from the third selection signal SEL 3 . 
     First, as illustrated in  FIG. 11 , in the first horizontal scanning period H 1  of the first frame period, the third signal line S 3  and the fourth signal line S 4  are simultaneously selected, and the same third image signal D 3  is supplied to both the third signal line S 3  and the fourth signal line S 4 . 
     Further, in the first horizontal scanning period H 1 , the seventh signal line S 7  and the eighth signal line S 8  are simultaneously selected, and the same seventh image signal D 7  is supplied to both the selected seventh signal line S 7  and the eighth signal line S 8 . 
     As shown in  FIG. 12A , the gradation distribution of the first horizontal scanning period H 1  is such that, both the gradations of the third pixel  21   c  to which the third image signal D 3  are written from the third signal line S 3  and the gradations of the fourth pixel  21   d  to which the third image signal D 3  are written from the fourth signal line S 4  become 120 gradations. 
     In addition, both the gradations of the seventh pixel  21   g  to which the seventh image signal D 7  are written from the seventh signal line S 7 , and the gradations of the eighth pixel  21   h  to which the seventh image signal D 7  are written from the eighth signal line S 8 , become 200 gradations. Up to this point is the same as the driving method of Third Exemplary Embodiment. 
     Next, a driving method of the second horizontal scanning period H 2  will be described. First, as illustrated in  FIG. 11 , after the eighth selection signal SEL 8  is supplied and the eighth signal line S 8  is selected, the eighth image signal D 8  is supplied to the eighth signal line S 8 . As illustrated in  FIG. 12A , the gradations of the eighth pixel  21   h  to which the eighth image signal D 8  is written are 220 gradations. 
     Next, after the first selection signal SEL 1  is supplied and the first signal line S 1  is selected, the first image signal D 1  is supplied to the first signal line S 1 . As shown in  FIG. 12A , the gradations of the first pixel  21   a  to which the first image signal D 1  that was written are 80 gradations. 
     Next, the second selection signal SEL 2  and the third selection signal SEL 3  are supplied simultaneously, and the same second image signal D 2  is supplied to both the selected second signal line S 2  and the third signal line S 3 . As shown in  FIG. 12A , the gradations of the second pixel  21   b  and the third pixel  21   c  to which the second image signal D 2  is written are the same 100 gradations. 
     Next, the fourth selection signal SEL 4  is supplied to select the fourth signal line S 4 , and the fourth image signal D 4  is written to the fourth pixel  21   d  via the fourth signal line S 4 . Then, the fifth selection signal SEL 5  is supplied to select the fifth signal line S 5 , and the fifth image signal D 5  is written to the fifth pixel  21   e  via the fifth signal line S 5 . 
     As shown in  FIG. 12A , the gradations of the fourth pixel  21   d  to which the fourth image signal D 4  is written are 140 gradations. As shown in  FIG. 12A , the gradations of the fifth pixel  21   c  to which the fifth image signal D 5  is written are 160 gradations. 
     Next, the sixth selection signal SEL 6  and the seventh selection signal SEL 7  are supplied simultaneously, and the same sixth image signal D 6  is supplied to both the selected sixth signal line S 6  and the seventh signal line S 7 . As shown in  FIG. 12A , the gradations of the sixth pixel  21   f  and the seventh pixel  21   g  to which the sixth image signal D 6  is written are the same 180 gradations. 
     Next, a driving method of the third horizontal scanning period H 3  will be described. First, the seventh selection signal SEL 7  is supplied to select the seventh signal line S 7 , and the seventh image signal D 7  is written to the seventh pixel  21   g  via the seventh signal line S 7 . As shown in  FIG. 12A , the gradations of the seventh pixel  21   g  are 200 gradations. 
     Next, the eighth selection signal SEL 8  is supplied to select the eighth signal line S 8 , and the eighth image signal D 8  is written to the eighth pixel  21   h  via the eighth signal line S 8 . As shown in  FIG. 12A , the gradations of the eighth pixel  21   h  are 220 gradations. 
     Next, the first selection signal D 1  and the second selection signal SEL 2  are supplied simultaneously, and the same first image signal D 1  is supplied to both the selected first signal line S 1  and the second signal line S 2 . The gradations of the first pixel  21   a  and the second pixel  21   b  to which the first image signal D 1  is written are the same 80 gradations. Thereafter, the image signal D is sequentially written to the third pixel  21   c  to the sixth pixel  21   f , and the writing operation of the third horizontal scanning period H 3  is completed. 
     In this way, by changing the combination of the simultaneously selected signal lines  23  and changing the order of the selected signal lines  23  for each horizontal scanning period H, regions of adjacent pixels  21  having the same gradation can be dispersed among one frame of image. Thus, it is possible to make the deterioration of image quality difficult to be visually recognizable. 
     Thereafter, as illustrated in  FIG. 11 , during the fourth horizontal scanning period H 4  to the eighth horizontal scanning period H 8 , the image signal D is written to the pixels  21  while changing the order of supplying the selection signals SEL. Accordingly, the driving in the first frame period is completed. 
     As shown in  FIG. 12B , the driving method of the second frame period starts in the drive mode of the second horizontal scanning period H 2  (see  FIG. 11 ). Hereinafter, driving is performed in an order from the drive mode of the third horizontal scanning period H 3  to the drive mode of the first horizontal scanning period H 1 . The gradation distribution of the second frame period is shown in the table of  FIG. 12B . 
     As shown in  FIG. 12C , the driving method of the third frame period starts in the drive mode of the third horizontal scanning period H 3  (see  FIG. 11 ). Hereinafter, driving is performed in an order from the drive mode of the fourth horizontal scanning period H 4  to the drive mode of the second horizontal scanning period H 2 . The gradation distribution of the third frame period is shown in the table of  FIG. 12C . 
     As shown in  FIG. 12D , the driving method of the fourth frame period starts in the drive mode of the fourth horizontal scanning period H 4  (see  FIG. 11 ). Hereinafter, driving is performed in an order from the drive mode of the fifth horizontal scanning period H 5  to the drive mode of the third horizontal scanning period H 3 . The gradation distribution of the fourth frame period is shown in the table of  FIG. 12D . 
     As shown in  FIG. 12E , the driving method of the fifth frame period starts in the drive mode of the fifth horizontal scanning period H 5  (see  FIG. 11 ). Hereinafter, driving is performed in an order from the drive mode of the sixth horizontal scanning period H 6  to the drive mode of the fourth horizontal scanning period H 4 . The gradation distribution of the fifth frame period is shown in the table of  FIG. 12E . 
     As shown in  FIG. 12F , the driving method of the sixth frame period starts in the drive mode of the fifth horizontal scanning period H 6  (see  FIG. 11 ). Hereinafter, driving is performed in an order from the drive mode of the seventh horizontal scanning period H 7  to the drive mode of the fifth horizontal scanning period H 5 . The gradation distribution of the sixth frame period is shown in the table of  FIG. 12F . 
     As shown in  FIG. 12G , the driving method of the seventh frame period starts in the drive mode of the fifth horizontal scanning period H 7  (see  FIG. 11 ). Hereinafter, driving is performed in an order from the drive mode of the eighth horizontal scanning period H 8  to the drive mode of the sixth horizontal scanning period H 6 . The gradation distribution of the seventh frame period is shown in the table of  FIG. 12G . 
     As shown in  FIG. 12H , the driving method of the eighth frame period starts in the drive mode of the fifth horizontal scanning period H 8  (see  FIG. 11 ). Hereinafter, driving is performed in an order from the drive mode of the first horizontal scanning period H 1  to the drive mode of the seventh horizontal scanning period H 7 . The gradation distribution of the eighth frame period is shown in the table of  FIG. 12H . 
     As described above, according to the driving method of the electro-optical device  20  of Fourth Exemplary Embodiment, the following effects can be obtained. 
     (5) According to Fourth Exemplary Embodiment, the order (timing) of supplying the selection signals SEL is changed for each horizontal scanning period H, thus, in each horizontal scanning period and each frame period, the positions of the pixels  21  to which the same image signal D is written can be dispersed, and it is possible to make the deterioration of image quality difficult to be visually recognized. 
     Modification Examples 
     Further, the embodiments described above may be modified as follows. 
     In the embodiments described above, the pre-charge signal PRC is supplied at the same timing at the beginning of each horizontal scanning period H, but the present disclosure is not limited to this, and may be the following aspects. 
       FIG. 13  is a timing chart illustrating a driving method of a modified example. Note that, the driving method of the modified example is the same as Fourth Exemplary Embodiment except for the operation of supplying the per-charge signal PRC. Therefore, the gradation distribution in each frame period is also the same as that of  FIGS. 12A to 12H . 
     A pre-charge circuit (referred to as a sequential pre-charge circuit in the present modified example) can be used, for example, a known technique, and is disposed in the signal line driving circuit  53  (not illustrated). Specifically, for example, as illustrated in  FIG. 13 , in the first horizontal scanning period, the second pre-charge signal PRC 2  is supplied immediately before the second selection signal SEL 2 . 
     Thereafter, the third pre-charge signal PRC 3  is supplied immediately before the third selection signal SEL 3  is supplied, the fourth pre-charge signal PRC 4  is supplied immediately before the fourth selection signal SEL 4  is supplied, and then the pre-charge signal PRC is sequentially supplied (sequential pre-charge driving). In this way, by supplying the pre-charge signal PRC immediately before the selection signal SEL is supplied, a dedicated pre-charge period can be reduced and the high speed driving can be accommodated. 
     Further, in the embodiments described above, the gradation distribution was set such that, the first pixel  12   a  to the eighth pixel  12   h  are sequentially set to be 80 gradations, 100 gradations, 120 gradations, 140 gradations, 160 gradations, 180 gradations, 200 gradations, and 220 gradations, but the gradation distribution is not limited to this, for example, the gradations may be set in which numerical values for each frame period are averaged. 
       FIG. 14  is a table showing the gradation of a modified example of First Exemplary Embodiment. As illustrated in  FIG. 14 , in order from the first pixel  21   a  column to the eighth pixel  21   h  column, 77.5 gradations, 97.5 gradations, 118 gradations, 138 gradations, 178 gradations, 178 gradations, and 218 gradations are sequentially set. 
     Specifically, the gradation for each frame period is an average value. For example, in the first pixel  21   a  column, only the eighth frame period is set to be 60 gradations, thus the gradation is calculated and averaged as (80 gradations×7 frames+60 gradations×1 frame)/8 frames. 
     Further, as shown in  FIG. 15 , the gradations may be set to average gradation values in Second Exemplary Embodiment to Fourth Exemplary Embodiment. 
     Furthermore, in the embodiments described above, the simultaneously selected signal lines  23  are referred to as two adjacent signal lines  23 , but the present disclosure is not limited to this, and three or more adjacent signal lines may be simultaneously selected as a set to supply the same image signal D. 
     In addition, as in Second Exemplary Embodiment to Fourth Exemplary Embodiment, the combination of the simultaneously selected signal lines  23  was made into two sets, but the present disclosure is not limited to this, it may be made into three sets or more. 
     Further, in the embodiments described above, the configuration of eight selection signals SEL (SEL 1  to SEL 8 ) is described, but the present disclosure is not limited to this, the configuration of four selection signals SEL, the configuration of 12 selection signals SEL, or the configuration of 16 selection signals SEL may be used. 
     Further, in the embodiments described above, the writing polarity to the pixel  21 , that is, a positive polarity writing or a negative polarity writing is not mentioned, but may be as follows. For example, when the drive frequency is 240 Hz (four-time speed driving) as described in First Exemplary Embodiment, writing is performed such that the positive polarity writing in the first frame period, the negative polarity writing in the second frame period, the positive polarity writing in the third frame period, and the negative polarity writing in the fourth frame period. In this case, in the second frame period, writing is performed without changing the combination of the two signal lines  23  selected simultaneously. Furthermore, in the fourth frame period, writing is performed without changing the combination of the two signal lines selected simultaneously. The change in the combination of the two signal lines  23  selected simultaneously is performed in the first frame period and the third frame period. When the combination is changed in the second frame period and the fourth frame period, the polarity balance between the positive polarity writing and the negative polarity writing is lost, which causes the occurrence of burn-in or flicker, however, by not changing the combination of the two signal lines  23  simultaneously selected in the second frame period and the fourth frame period, the occurrence of burn-in and flicker can be suppressed. 
     Further, in First Exemplary Embodiment and Second Exemplary Embodiment, the combination of the signal lines  23  is changed for each frame period, but the following may be used. For example, when the drive frequency is 480 Hz (eight-time speed driving), the combination of the signal lines  23  may be changed every two frame periods or every four frame periods. Furthermore, in the modified example described above, the combination of the signal lines  23  may not be changed in a frame of a set of positive and negative polarities. 
     Further, in Third Exemplary Embodiment and Fourth Exemplary Embodiment, the combination of signal lines  23  is changed for each horizontal scanning period, but the combination of the signal lines  23  may be changed every plural horizontal scanning periods. In addition, as in First Exemplary Embodiment and Second Exemplary Embodiment, in each frame period, the combination of the signal lines  23  may be changed among the signal line groups. 
     Contents derived from the exemplary embodiments will be described below. 
     An electro-optical device includes a plurality of signal lines, a plurality of scanning lines, pixels arranged corresponding to intersections of the plurality of signal lines and the plurality of scanning lines, image signal lines arranged respectively corresponding to k signal lines among the plurality of signal lines, k switches arranged between the image signal lines and the k signal lines respectively, a selection signal output circuit configured to output a selection signal for selecting the k switches, and an image signal output circuit outputting an image signal to the pixels via the image signal lines, wherein the selection signal output circuit outputs a selection signal for simultaneously selecting a set of switches, which correspond to a set of adjacent signal lines, among the k switches in a partial period obtained by time-dividing a horizontal scanning period, and outputs a selection signal for selecting remaining switches among the k switches one at a time in a remaining period of the time-divided horizontal scanning period, and the image signal output circuit supplies a same image signal to a set of adjacent signal lines corresponding to the simultaneously selected set of switches in a partial period obtained by time-dividing the horizontal scanning period. 
     According to this configuration, a set of switches corresponding to a set of adjacent signal lines among the k switches is simultaneously selected to supply the same image signal, thus, as compared to a case where one signal line is selected to supply the image signal, the selecting period can be shortened by one period. In addition, the adjacent signal lines, in other words, the same image signal is written to a part of the pixels, thus deterioration of the display image can be suppressed. As a result, the time of writing the image signal to the signal line can be secured, and high-resolution display quality can be provided. Specifically, for example, brightness and image quality can be improved by increasing the writing time as much as reducing the number of times of writing. Furthermore, the drive frequency can be increased as much as reducing the number of times of writing, and high resolution and high speed driving can be easily performed. 
     In the electro-optical device described above, it is desirable that the selection signal output circuit changes, at predetermined time intervals, the combination of the set of switches that are simultaneously selected. 
     According to this configuration, the combination of the simultaneously selected set of switches is changed at predetermined time intervals, thus deterioration of the image quality can be suppressed. 
     In the electro-optical device described above, the selection signal output circuit may perform p-time speed driving that supplies the same image signal to the pixels p times for each vertical scanning period, and may change, p times or 2/p times in p vertical scanning periods, a combination of the set of switches that are simultaneously selected. 
     According to this configuration, the combination of the simultaneously selected set of switches can be changed p times or 2/p times during the p vertical scanning periods, thus pixels to which the same image signal is written can be dispersed in the display screen, and deterioration in display quality can be suppressed. 
     In the electro-optical device described above, the selection signal output circuit may simultaneously select two sets of switches, which respectively correspond to two sets of adjacent signal lines, among the k switches in a partial time period obtained by time-dividing the horizontal scanning period, and may supply a first image signal to first set of adjacent signal lines corresponding to a first set of switches and also supply a second image signal to a second set of adjacent signal lines corresponding to a second set of switches. 
     According to this configuration, the first image signal is supplied to the first set of adjacent signal lines corresponding to the first set of switches, and the second image signal is supplied to the second set of adjacent signal lines corresponding to the second set of switches, thus the selecting period can be shortened by two periods. As a result, the time of writing the image signal to the signal line can be secured, and high-resolution display quality can be provided. 
     In the electro-optical device described above, a vertical scanning period may include a first horizontal scanning period and a second horizontal scanning period, and the selection signal output circuit may change a combination of the set of switches that are simultaneously selected in the first horizontal scanning period and the second horizontal scanning period. 
     According to this configuration, the combination of the simultaneously selected set of switches is changed between the first horizontal scanning period and the second horizontal scanning period, thus, pixels to which the same image signal is written can be dispersed. As a result, deterioration in display quality can be suppressed. 
     In the electro-optical device described above, the selection signal output circuit may supply an image signal, which is to be supplied to any one signal line of the set of adjacent signal lines corresponding to the set of switches that are simultaneously selected, to also the other signal line of the set of adjacent signal lines corresponding to the set of switches that are simultaneously selected. 
     According to this configuration, the image signal to be supplied to the signal line of any one of a set of adjacent signal lines corresponding to the simultaneously selected set of switches can be supplied to the other signal lines of the set of adjacent signal lines corresponding to the simultaneously selected set of switches, thus the selecting period can be shortened, and the writing time can be secured. 
     In the electro-optical device described above, the image signal output circuit may supply an image signal, which is obtained by averaging image signals in a plurality of vertical scanning periods, to a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected. 
     According to this configuration, the same image signal is supplied in accordance with the averaged image signal, thus changes in gradation can be suppressed, and deterioration in the image can be suppressed. 
     There is a driving method for an electro-optical device that includes a plurality of signal lines, a plurality of scanning lines, pixels arranged corresponding to intersections of the plurality of signal lines and the plurality of scanning lines, image signal lines arranged respectively corresponding to k signal lines among the plurality of signal lines, k switches arranged between the image signal lines and the k signal lines respectively, a selection signal output circuit configured to output a selection signal for selecting the k switches, and an image signal output circuit configured to output an image signal to the pixels via the image signal lines, the driving method including outputting by the selection signal output circuit a selection signal for simultaneously selecting a set of switches, which correspond to a set of adjacent signal lines, among the k switches in a partial period obtained by time-dividing a horizontal scanning period, and outputting a selection signal for selecting remaining switches among the k switches one at a time in a remaining period of the time-divided horizontal scanning period; and supplying by the image signal output circuit a same image signal to a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected in a partial period obtained by time-dividing the horizontal scanning period. 
     According to this method, a set of switches corresponding to a set of adjacent signal lines among the k switches is simultaneously selected to supply the same image signal, thus, as compared to a case where one signal line is selected to supply the image signal, the selecting period can be shortened by one period. In addition, the adjacent signal lines, in other words, the same image signal is written to a part of the pixels, thus deterioration of the display image can be suppressed. As a result, the time of writing the image signal to the signal line can be secured, and high-resolution display quality can be provided. Specifically, for example, brightness and image quality can be improved by increasing the writing time as much as reducing the number of times of writing. Furthermore, the drive frequency can be increased as much as reducing the number of times of writing, and high resolution and high speed driving can be easily performed. 
     In the driving method for the electro-optical device described above, the selection signal output circuit may change, at predetermined time intervals, a combination of the set of switches that are simultaneously selected. 
     According to this method, the combination of the simultaneously selected set of switches is changed at predetermined time intervals, thus deterioration of the image quality can be suppressed. 
     In the driving method for the electro-optical device described above, the selection signal output circuit may perform p-time speed driving that supplies the same image signal to the pixels p times for each vertical scanning period, and may change, p times or 2/p times in p vertical scanning periods, a combination of the set of switches that are simultaneously selected. 
     According to this method, the combination of the simultaneously selected set of switches can be changed p times or 2/p times during the p vertical scanning periods, thus pixels to which the same image signal is written can be dispersed in the display screen, and deterioration in display quality can be suppressed. 
     In the driving method for the electro-optical device described above, the selection signal output circuit may simultaneously select two sets of switches, which respectively correspond to two sets of adjacent signal lines, among the k switches in a partial time period obtained by time-dividing the horizontal scanning period, and may supply a first image signal to a first set of adjacent signal lines corresponding to a first set of switches and also supply a second image signal to a second set of adjacent signal lines corresponding to a second set of switches. 
     According to this method, the first image signal is supplied to the first set of adjacent signal lines corresponding to the first set of switches, and the second image signal is supplied to the second set of adjacent signal lines corresponding to the second set of switches, thus the selecting period can be shortened by two periods. As a result, the time of writing the image signal to the signal line can be secured, and high-resolution display quality can be provided. 
     In the driving method for the electro-optical device described above, a vertical scanning period may include a first horizontal scanning period and a second horizontal scanning period, and the selection signal output circuit changes a combination of the set of switches that are simultaneously selected in the first horizontal scanning period and the second horizontal scanning period. 
     According to this method, the combination of the simultaneously selected set of switches is changed between the first horizontal scanning period and the second horizontal scanning period, thus, pixels to which the same image signal is written can be dispersed. As a result, deterioration in display quality can be suppressed. 
     In the driving method for the electro-optical device described above, the selection signal output circuit may supply an image signal, which is to be supplied to any one signal line of a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected, to also the other signal line of a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected. 
     According to this method, the image signal to be supplied to the signal line of any one of a set of adjacent signal lines corresponding to the simultaneous selected set of switches can be supplied to the other signal lines of the set of adjacent signal lines corresponding to the simultaneously selected set of switches, thus the selecting period can be shortened, and the writing time can be secured. 
     In the driving method for the electro-optical device described above, the image signal output circuit may supply an image signal, which is obtained by averaging image signals in a plurality of vertical scanning periods, to a set of adjacent signal lines corresponding to the set of switches that are simultaneously selected. 
     According to this method, the same image signal is supplied in accordance with the averaged image signal, thus changes in gradation can be suppressed, and deterioration in the image can be suppressed. 
     An electronic apparatus includes the electro-optical device described above. 
     According to this configuration, an electronic apparatus capable of obtaining high-resolution display quality can be provided.