JP2006235282A - Electrooptical device and its driving method, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make an electrooptical device such as a liquid crystal display device small-sized while ensuring the area of an image display region as it is. <P>SOLUTION: The electrooptical device includes a plurality of scanning lines and a plurality of data lines, a plurality of pixel portions, N (N: a natural number of ≥2) image signal lines which are supplied with N serial-parallel converted image signals and also supplied with a precharge signal of designated potential at a time before the image signals, an image signal supply section which supplies the image signals by data line groups in an image signal supply period and also supplies the precharge signal to the plurality of data lines in a precharge period before the image signal supply period, and a short circuit which electrically short-circuits the N image signal lines to one another in at least part of the precharge period. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electro-optical device such as a liquid crystal device, a driving method thereof, and a technical field of an electronic apparatus such as a liquid crystal projector including the electro-optical device.

  This type of electro-optical device is generally driven on the basis of an image signal subjected to serial-parallel conversion. For example, in a liquid crystal device, a plurality of data lines wired to an image display area on a substrate are divided into blocks every predetermined number, and serial-parallel converted image signals are included in the block in block units. The data line is supplied via a sampling switch. Thus, a predetermined number of data lines are simultaneously driven and a plurality of data lines are sequentially driven every predetermined number. Further, in this type of electro-optical device, it is desired to supplement the writing capability of the sampling circuit when writing an image signal to the pixel portion via a data line having a wiring capacity that is greater or smaller.

  For this reason, in general, for example, during a blanking period of an image signal, precharge is performed in which a precharge signal having a predetermined potential is written to a data line prior to the image signal. For this precharge, a so-called “video precharge” method in which a precharge signal is supplied through the same signal supply path as that of an image signal, as disclosed in, for example, Patent Document 1, is common. In particular, when inversion driving is performed for each field or frame of an image signal, writing an image signal through a data line that is always at the opposite polarity to the image signal to be supplied requires a large writing capability. Therefore, such precharge is extremely effective. In addition, video precharge is advantageous because it does not require a dedicated signal supply path to be built separately from the signal supply path of the image signal unlike traditional precharge.

JP-A-8-334745

  However, according to the technique of Patent Document 1 described above, that is, video precharge, when driving based on a serial-parallel converted image signal, each of a plurality of image signals corresponding to the number of serial-parallel conversions. On the other hand, the same precharge signal is supplied from the external circuit all at once. Then, in most cases, the plurality of image signal lines have different time constants due to the planar layout on the substrate. For this reason, the plurality of data lines connected to the plurality of image signal lines are charged with different potentials during the precharge period. Therefore, due to the difference in potential after precharging, even if image signals having the same potential are supplied, they are charged to different potentials. As a result, luminance unevenness or data for each series of a plurality of image signals. There is a technical problem that vertical stripes along the line can occur. This problem becomes more serious as the drive frequency is increased, and the higher the image display is desired. That is, it can be a very serious obstacle to high-quality image display.

  The present invention has been made in view of the above problems. For example, it is possible to prevent the occurrence of uneven brightness and vertical stripes at the boundary between blocks as described above, and to display a high-quality image. It is an object of the present invention to provide an electro-optical device, a driving method thereof, and various electronic apparatuses including the electro-optical device.

  In order to solve the above problems, the electro-optical device of the present invention is electrically connected to the plurality of scanning lines and the plurality of data lines wired in the image display region on the substrate, and to the scanning lines and the data lines, respectively. In order to drive the plurality of pixel portions and the plurality of data lines for each data line group including N data lines as a group, N (where N is a natural number of 2 or more) serial-parallels N image signal lines to which a converted image signal is supplied and a precharge signal having a predetermined potential is supplied all at once in advance of the image signal and the N image signal lines are respectively supplied. The supplied image signal is supplied for each data line group in the image signal supply period, and the precharge signal supplied in a batch via the N image signal lines precedes the image signal supply period. In the precharge period, the plurality of Chromatography comprising an image signal supply unit supplies the data line, at least a portion of the precharge period, and a short circuit mutually electrically shorting to the image signal lines of the N lines.

  According to the electro-optical device of the present invention, at the time of driving, the N image signals subjected to serial-parallel conversion are supplied to the N image signal lines and further supplied to the image signal supply unit. For example, N image signals are converted into three-phase, six-phase, twelve-phase, twenty-four-phase, and so on by an external circuit in order to realize high-definition image display while suppressing an increase in drive frequency. Etc., and generated by being converted into a plurality of parallel image signals.

  In parallel with the supply of the image signals, N image signals are sequentially supplied to the plurality of data lines for each data line group by the image signal supply unit. The image signal supply unit includes, for example, a data line driving circuit and a sampling circuit, and a sampling signal is sequentially supplied to each sampling switch corresponding to the data line group by the data line driving circuit. Then, N image signals are sequentially supplied to the plurality of data lines by the sampling circuit for each data line group according to the sampling signal. Therefore, data lines belonging to the same data line group are driven simultaneously. The sampling switch is configured by, for example, a single-channel TFT, and the source is electrically connected to the branch wiring, the drain is connected to the data line, and the sampling signal is supplied to the gate so that the sampling switch is turned on. Become.

  When the data line is driven in this way, in each pixel unit, for example, the pixel electrode is selected according to the scanning signal supplied from the scanning line driving circuit via the scanning line, and the pixel switching element that performs the switching operation Then, an image signal is supplied from the data line to the pixel electrode. Thereby, for example, a liquid crystal element as a display element performs image display based on the supplied image signal.

  Video precharge is performed in a precharge period preceding an image signal supply period for supplying an image signal. Video precharge refers to control in which a data line is charged or discharged via an image signal line to bring the potential of the data line close to the image signal potential in advance in order to prevent insufficient writing. Video precharge is performed on a plurality of data lines all at once or for each data line according to the precharge timing. More specifically, at the time of data writing, the data line is brought into conduction with the image signal line at the timing to be written, but at the time of precharging, the data line is brought into conduction with the image signal line at the timing to be precharged. In the latter case, not an image signal but a precharge signal is transmitted on the image signal line. As a result, a precharge signal is applied to the data line, and the potential of the data line is secured.

  In particular, in many cases, the plurality of image signal lines have mutually different time constants due to the planar layout on the substrate. Therefore, if the precharge signals are separately supplied via the plurality of image signal lines, the data lines connected to the plurality of image signal lines are charged to different potentials during the precharge period. Will be.

  However, according to the electro-optical device of the present invention, the N image signal lines are electrically short-circuited to each other by at least a part of the precharge period by the short circuit. For this reason, the time constants of the N image signal lines are aligned regardless of the planar layout on the substrate. In other words, the time constants of the N image signal lines are almost the same in a practical or practical sense. Therefore, it is possible to prevent the potential difference after precharging from occurring.

  As a result, it is possible to prevent luminance unevenness or vertical stripes along the data lines from occurring for each series of a plurality of image signals, and finally it is possible to display a high-quality image.

  In the electro-optical device according to the aspect of the invention, the short circuit shorts the N image signal lines in synchronization with a precharge period selection signal that defines the precharge period.

  According to this aspect, the short circuit shorts the N image signal lines in synchronization with the precharge period selection signal that defines the precharge period, that is, only during the precharge period. For this reason, since the N image signal lines are short-circuited during the precharge period, the time constants of the plurality of image signal lines are aligned regardless of the planar layout on the substrate. Accordingly, it is possible to prevent the plurality of data lines connected to the plurality of image signal lines from being charged to different potentials during the precharge period.

  In another aspect of the electro-optical device according to the aspect of the invention, the electro-optical device further includes a delay circuit that delays a precharge period selection signal that defines the precharge period, and the short circuit is synchronized with the delayed precharge period selection signal. The N image signal lines are short-circuited.

  According to this aspect, the precharge period selection signal that defines the precharge period is supplied to the delay circuit, and the precharge period selection signal is delayed by the delay circuit. In synchronization with the delayed precharge period selection signal, the short circuit shorts the N image signal lines, that is, the short circuit is delayed by the same length as the precharge period after the precharge period.

  At the end of the precharge period, the supply of the precharge signal from the image signal line is completed at the same time. Therefore, the precharge signal of the image signal line fluctuates at the end of the precharge period. The time until this fluctuation is recovered varies depending on the time constants of the plurality of image signal lines. Therefore, when the short-circuiting of the plurality of image signal lines is finished at the end of the precharge period, the time constants of the plurality of image signal lines are different from each other, so that the time until the fluctuation is recovered may be different. is there.

  However, according to this aspect, since the short circuit is delayed by the same length as the precharge period after the precharge period, the plurality of image signal lines are short-circuited even at the end of the precharge period. For this reason, a plurality of image signal lines are short-circuited until the fluctuation of the precharge signal of the image signal line at the end of the precharge period is recovered. As a result, it is possible to more effectively prevent the plurality of data lines connected to the plurality of image signal lines from being charged to different potentials during the precharge period.

  In another aspect of the electro-optical device according to the aspect of the invention, a short period selection signal that defines a period including the precharge period is supplied from the outside, and the short circuit is synchronized with the supplied short period selection signal. The N image signal lines are short-circuited.

  According to this aspect, the short period selection signal that defines the period including the precharge period is supplied from the outside. In synchronization with the supplied short period selection signal, the short circuit shorts the N image signal lines, that is, from a time point earlier than the start time of the precharge period to a time point later than the end time of the precharge period. Short-circuit the same length as the precharge period. For this reason, the precharge signal rises at the start of the precharge period and falls at the end of the precharge period, and is affected by fluctuations in the precharge signal due to the difference in the time constant of the image signal line. You do n’t have to. Therefore, it is possible to more effectively prevent the plurality of data lines connected to the plurality of image signal lines from being charged to different potentials during the precharge period.

  In another aspect of the electro-optical device according to the aspect of the invention, the image signal supply unit may include a plurality of samplings that supply the image signals respectively supplied from the plurality of image signal lines to the data lines according to a sampling signal. A sampling circuit including a switch; and a data line driving circuit that sequentially supplies the sampling signal for each of the sampling switches corresponding to the data line group, wherein the plurality of sampling switches include a precharge period that defines the precharge period. In accordance with the charge period selection signal, the conductive state is brought together.

  According to this aspect, the image signal supply unit includes a sampling circuit including a plurality of sampling switches and a data line driving circuit. The data line driving circuit sequentially supplies a sampling signal for each sampling switch corresponding to the data line group. When the plurality of sampling switches are to supply image signals, the image signals respectively supplied from the plurality of image signal lines are sampled according to the sampling signals and supplied to the data lines. When the plurality of sampling switches are to be precharged, they are collectively turned on according to a precharge period selection signal that defines a precharge period. For this reason, the precharge signal can be supplied to the data line group collectively during the precharge period. Note that the sampling switch is composed of, for example, a single-channel TFT, and the source is electrically connected to the image signal line, the drain is connected to the data line, and the sampling signal is supplied to the gate to turn it on. It is said.

  In another aspect of the electro-optical device according to the aspect of the invention, the short circuit includes a source connected to one of a pair of two adjacent image signal lines of the N image signal lines and a drain connected to the other. Each of the pairs has a transistor connected and selectively short-circuiting the pair with each other.

  According to this aspect, the gate of a transistor such as a thin film transistor having a source connected to one of a pair of two adjacent image signal lines of N image signal lines and a drain connected to the other is turned on. By entering the state, the pair of two image signal lines adjacent to each other becomes conductive. By selectively turning on the gates of these transistors, a pair of two adjacent image signal lines can be selectively short-circuited. Therefore, the time constants of the plurality of image signal lines can be all or selectively aligned regardless of the planar layout on the substrate. Therefore, it is possible to prevent the potential difference after precharging from occurring. A transistor that short-circuits a pair of two adjacent image signal lines is not limited to a thin film transistor, and may be a bulk transistor or the like.

  In an aspect having a transistor connected to a pair of two adjacent image signal lines, a precharge period selection signal for defining the precharge period is delayed at the gate of the transistor. Any one of the generated signal and a short period selection signal defining a period including the precharge period may be input.

  In this case, among the precharge period selection signal that defines the precharge period, the signal that the precharge period selection signal is delayed, and the short period selection signal that defines the period including the precharge period at the gate of the transistor When any one signal is input, two adjacent image signal lines connected to the transistor are short-circuited in synchronization with the signal. Therefore, when the precharge period selection signal is input, the image signal line can be short-circuited in synchronization with the precharge period. When a signal obtained by delaying the precharge period selection signal is input, it is possible to avoid the influence of voltage fluctuation at the end of the precharge period. In addition, when a short period selection signal that defines a period including a precharge period is input, the precharge signal of the image signal line is not affected by fluctuation at the start and end of the precharge period. Can be done.

  In another aspect of the electro-optical device of the present invention, the N image signal lines are drawn so as to have different wiring lengths from the external circuit connection terminal to the image signal supply unit on the substrate. It has been turned.

  According to this aspect, the N image signal lines can be planarly laid out with different wiring lengths from the external circuit connection terminal to the image signal supply unit on the substrate. Further, since the N image signal lines are electrically short-circuited to each other in at least a part of the precharge period by the short circuit, the time constant of the N image signal lines is set on the substrate. It will be almost complete regardless of the planar layout. Therefore, it is possible to prevent the potential difference after precharging from occurring.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention (including various aspects thereof).

  Since the electronic apparatus of the present invention includes the above-described electro-optical device of the present invention, a projection display device, a television, a mobile phone, an electronic notebook, a word processor, a view capable of performing high-quality image display. Various electronic devices such as a finder type or a monitor direct-view type video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized. Further, as an electronic apparatus of the present invention, for example, an electrophoretic device such as electronic paper, an electron emission device (Field Emission Display and a Conduction Electron-Emitter Display), an electrophoretic device, and an apparatus using the electron emission device, DLP (Digital Light Processing) and the like can also be realized.

  In order to solve the above problems, the first electro-optical device driving method of the present invention includes a plurality of scanning lines and a plurality of data lines wired in an image display region on a substrate, and the scanning lines and the data lines. A driving method for driving an electro-optical device including a plurality of pixel portions electrically connected to each other and N image signal lines, wherein the N pixels are supplied during a precharge period preceding an image signal supply period. A precharge step of supplying a precharge signal of a predetermined potential to the plurality of data lines collectively through the image signal lines, and the N image signal lines are electrically short-circuited for the precharge period. N (where N is a natural number of 2 or more) serial-parallel conversion is performed in order to drive every N data lines as one group during the shorting process and the image signal supply period. Image signal Via the image signal lines of the N present and an image signal supply step of supplying each said data line groups.

  According to the first electro-optical device driving method of the present invention, the N image signal lines are short-circuited only during the precharge period. Therefore, it is possible to prevent a plurality of data lines connected to a plurality of image signal lines from being charged to different potentials during the precharge period.

  In order to solve the above problem, the second electro-optical device driving method of the present invention includes a plurality of scanning lines and a plurality of data lines wired in an image display region on a substrate, and the scanning lines and the data lines. A driving method for driving an electro-optical device including a plurality of pixel portions electrically connected to each other and N image signal lines, wherein the N pixels are supplied during a precharge period preceding an image signal supply period. A precharge step of supplying a precharge signal of a predetermined potential to the plurality of data lines in a batch through the image signal lines, and a period that is delayed from the precharge period and has a length equal to the precharge period. In order to drive each of the N data lines as one group in the shorting process for electrically shorting N image signal lines to each other and the image signal supply period, N (however, N Is 2 or more Natural number) number of serial - parallel converted image signals, and an image signal supply step of supplying each said data line group via the image signal lines of the N lines.

  According to the second electro-optical device driving method of the present invention, the plurality of image signal lines are short-circuited even at the end of the precharge period. Therefore, it is possible to more effectively prevent the plurality of data lines connected to the plurality of image signal lines from being charged to different potentials during the precharge period.

  In order to solve the above-described problem, a third electro-optical device driving method of the present invention includes a plurality of scanning lines and a plurality of data lines wired in an image display region on a substrate, and the scanning lines and the data lines. A driving method for driving an electro-optical device including a plurality of pixel portions electrically connected to each other and N image signal lines, wherein the N pixels are supplied during a precharge period preceding an image signal supply period. A precharge step of supplying a precharge signal of a predetermined potential to the plurality of data lines in a batch via the image signal lines, and the N image signal lines are mutually connected during a period including the precharge period. N (where N is a natural number of 2 or more) serials for driving each data line group including N data lines in a short-circuiting step for electrically shorting and the image signal supply period. -Parallel conversion An image signal, via an image signal line of the N present and an image signal supply step of supplying each said data line groups.

  According to the third method of driving the electro-optical device of the present invention, the short-circuit is performed by the same length as the precharge period from the time point earlier than the start time of the precharge period to the time point later than the end time of the precharge period. For this reason, it is possible to more effectively prevent the plurality of data lines connected to the plurality of image signal lines from being charged to different potentials during the precharge period.

  Various aspects similar to the various aspects related to the electro-optical device of the present invention described above can also be applied as appropriate to the driving methods of the first to third electro-optical devices.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a driving circuit built-in type TFT active matrix driving type liquid crystal device, which is an example of the electro-optical device of the present invention, is taken as an example.

(First embodiment)
The liquid crystal device according to the first embodiment will be described with reference to FIGS.

  First, the overall configuration of the liquid crystal device according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view showing the configuration of the liquid crystal device according to this embodiment, and FIG. 2 is a cross-sectional view taken along the line H-H ′ in FIG. 1.

  1 and 2, in the liquid crystal device according to the present embodiment, a TFT array substrate 10 and a counter substrate 20 are arranged to face each other. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are provided with a sealing material 52 provided in a seal region positioned around the image display region 10a. Are bonded to each other.

  In FIG. 1, a light-shielding frame light-shielding film 53 that defines the frame area of the image display region 10a is provided on the counter substrate 20 side in parallel with the inside of the seal region where the sealing material 52 is disposed. A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region located outside the sealing region in which the sealing material 52 is disposed in the peripheral region. The sampling circuit 7 is provided so as to be covered with the frame light shielding film 53 on the inner side of the seal region along the one side. Further, the scanning line driving circuit 104 is provided so as to be covered with the frame light-shielding film 53 inside the seal region along two sides adjacent to the one side. On the TFT array substrate 10, vertical conduction terminals 106 for connecting the two substrates with the vertical conduction material 107 are arranged in regions facing the four corner portions of the counter substrate 20. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

  On the TFT array substrate 10, a lead wiring 90 is formed for electrically connecting the external circuit connection terminal 102 to the data line driving circuit 101, the scanning line driving circuit 104, the vertical conduction terminal 106, and the like. .

  In FIG. 2, on the TFT array substrate 10, a laminated structure in which wiring such as a pixel switching TFT (Thin Film Transistor) as a driving element, a scanning line, and a data line is formed. In the image display area 10a, a pixel electrode 9a is provided in an upper layer of wiring such as a pixel switching TFT, a scanning line, and a data line. On the other hand, a light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. A counter electrode 21 made of a transparent material such as ITO is formed on the light shielding film 23 so as to face the plurality of pixel electrodes 9a.

  Although not shown here, in addition to the data line driving circuit 101 and the scanning line driving circuit 104, a short circuit described later is formed on the TFT array substrate 10. In addition to this, an inspection circuit, an inspection pattern, or the like for inspecting the quality, defects, etc. of the liquid crystal device during manufacture or at the time of shipment may be formed.

  Next, the operation of the liquid crystal device according to the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing a main configuration of the liquid crystal device according to this embodiment. FIG. 4 is a block diagram showing a drive system related to the video precharge operation in the configuration shown in FIG.

  3, in the liquid crystal device of this embodiment, a TFT array substrate 10 made of, for example, a quartz substrate, a glass substrate, or a silicon substrate and a counter substrate 20 (not shown here) are arranged to face each other with a liquid crystal layer interposed therebetween. The voltage applied to the pixel electrodes 9a that are partitioned in the image display region 10a is controlled to modulate the electric field applied to the liquid crystal layer for each pixel. Thereby, the amount of transmitted light between the two substrates is controlled, and the image is displayed in gradation. The liquid crystal device according to the present embodiment employs a TFT active matrix driving method, and a plurality of pixel electrodes 9 a arranged in a matrix and a plurality of pixel electrodes 9 a arranged in a matrix are arranged in the pixel display region 10 a of the TFT array substrate 10. The scanning line 2 and the data line 3 are formed, and a pixel portion corresponding to the pixel is constructed. Although not shown here, between each pixel electrode 9a and the data line 3, a TFT or a pixel electrode whose conduction or non-conduction is controlled according to a scanning signal supplied via the scanning line 2 respectively. A storage capacitor for maintaining the voltage applied to 9a is formed. In addition, a drive circuit such as the data line drive circuit 101 is formed in the peripheral area of the image display area 10a.

  The data line driving circuit 101 drives the sampling circuit 7, and converts the image signals VID1 to VID6 supplied to the image signal line 6 into sampling circuit driving signals Si (i = 1,...) As reference clock signals for applying data signals. n), and each is applied to the data line 3 as a data signal.

  The image signals VID <b> 1 to VID <b> 6 are serially / parallel-developed into six phases by an external image signal processing circuit, and input to the sampling circuit 7 via the six image signal lines 6.

  In FIG. 4, the sampling circuit 7 includes a sampling switch 71 composed of a P-channel or N-channel single-channel TFT or a complementary TFT. On the other hand, the sampling circuit drive signal Si (i = 1,..., N) generated based on the X-side clock signal CLX (and its inverted signal CLX ′) and the shift register start signal DX input into the data line drive circuit 101. ) Are input to six adjacent sampling switches 71 via control signal lines X1,. Accordingly, the sampling circuit 7 is driven for every six sampling switch 71 groups. In this way, when parallel image signals obtained by converting serial image signals are simultaneously supplied to a plurality of image signal lines 6, image signals can be input to the data lines 3 for each group and driven. The frequency is suppressed.

  In FIG. 3 again, the scanning line driving circuit 104 uses a reference clock for applying a scanning signal to scan a plurality of pixel electrodes 9a arranged in a matrix in the array direction of the scanning line 2 by a data signal and a scanning signal. A scanning signal generated based on a certain Y-side clock signal CLY (and its inverted signal CLY ′) and a shift register start signal DY is sequentially applied to a plurality of scanning lines 2. In that case, a voltage is simultaneously applied to each scanning line 2 from both ends.

  In the present embodiment, a precharge timing signal NRG (Noise Reduction Gate), which is an example of the “precharge period selection signal” according to the present invention, for the control signal lines X1,. Can be input. More specifically, each signal line for supplying the sampling circuit drive signal Si and the precharge timing signal NRG is connected to the control signal lines X1,... Xn via the OR circuit 51. The precharge timing signal NRG defines a precharge period prior to the writing period (that is, the image signal supply period) of the image signals VID1 to VID6, and is supplied all at once to the control signal lines X1,. Accordingly, all the sampling switches 71 are simultaneously turned on by the precharge timing signal NRG, and all the data lines 3 are simultaneously connected to the pixel signal lines 6. Here, in particular, the data line 3 is only made conductive by the image signal line 6 in the precharge period, and no signal is supplied from the image signal line 6. Alternatively, the data line 3 is connected to a predetermined potential different from the potential of the image signal via the image signal line 6 which is in a conductive state during the precharge period.

  Various timing signals such as a precharge timing signal NRG and a clock signal are generated by a timing generator (not shown) provided in the circuit unit and supplied to the liquid crystal device. Further, a power supply voltage necessary for driving each drive circuit is also supplied from the outside into the liquid crystal device.

  Further, the counter electrode potential LCC is supplied from the voltage source 200 to the signal line 8 drawn from the vertical conduction terminal 106. The counter electrode potential LCC is supplied to the counter electrode 21 via the signal line 8, the vertical conduction terminal 106, and the vertical conduction material 107 (see FIG. 1). Here, the voltage source 200 has a reference potential for forming a liquid crystal storage capacitor by appropriately holding a potential difference from the pixel electrode 9a as a counter electrode potential LCC, and a reference potential at least during a precharge period. It is configured to generate and output precharge potentials of different voltages. The counter electrode 21 is formed as a solid electrode on the entire surface of the image display region 10a in the counter substrate 20.

  Next, the video precharge operation of the liquid crystal device according to the present embodiment will be described with reference to FIGS. FIG. 5 is a timing chart of various signals in the drive system shown in FIG.

  As shown in the timing chart of FIG. 5, when the precharge timing signal NRG is input prior to the data writing period of the image signals VID1 to VID6, that is, the image signal supply period 32, in each field period 35, Are input to the gates of all the sampling switches 71 through the control signal lines X1,... Xn, and all the data lines 3 are brought into conduction with the image signal lines 6. That is, during the precharge period 31 defined by the precharge timing signal NRG, the data line 3 becomes conductive.

  In the precharge period 31, the precharge signal 45 is supplied to the image signal line 6 in accordance with the input of the precharge timing signal NRG, and is applied to all the data lines 3 at once. The precharge signal 45 is inserted into the image signals VID1 to VID6, and the data line 3 is charged or discharged by direct application of the precharge signal 45, that is, video precharged.

  Note that the polarity of the image signals VID <b> 1 to VID <b> 6 in each field is inverted at least every image signal supply period 32 by the surface inversion driving. For this reason, the polarity of the precharge signal 45 is inverted every precharge period 31 with reference to the counter electrode potential LCC. That is, the precharge signal 45 alternately takes a positive precharge level NRSH and a negative precharge level NRSL for each precharge period 31. Here, “polarity reversal” or “polarity reversal” refers to a predetermined potential other than the ground level, such as a counter electrode potential or a common potential, in addition to a case where the potential is reversed to a positive potential and a negative potential with respect to the ground level This also includes the case of inversion.

  In the image signal supply period 32, sampling circuit drive signals S 1, S 2, S 3,... Are generated in the data line drive circuit 101 by the input of the clock signal CLX (and its inverted signal CLX ′) and the shift register start signal DX. The signals are sequentially supplied to the sampling circuit 71. These sampling circuit drive signals Si drive the sampling circuit 7 for each group of six sampling switches 71 through the control signal lines X1,... Xn, and for each set of six data lines 3 corresponding to the sampling switches 71. Image signals VID1 to VID6 are supplied from the image signal line 6. These image signals VID1 to VID6 are applied from each data line 3 to the pixel electrode 9a of the selected pixel column, and data writing is performed.

  As shown in FIG. 5, the video precharge described above is performed in the precharge period 31 preceding the image signal supply period 32 for supplying the image signals VID1 to VID6. The video precharge according to the present embodiment is performed simultaneously on the plurality of data lines 3 in accordance with the precharge timing signal NRG. More specifically, in the image signal supply period 32, the data line 3 is electrically connected to the image signal line 6 at the timing to be written. In the precharge period 31, the data line 3 is connected to the image signal line at the timing to be precharged. 6 is conducted. In the precharge period 31, a precharge signal 45 is sent on the image signal line 6 instead of the image signals VID1 to VID6. As a result, the precharge signal 45 is applied to the data line 3, and the potential of the data line 3 is secured.

  4 and 5, particularly in the present embodiment, the plurality of image signal lines 6 almost always have different time constants due to the planar layout on the TFT array substrate 10. Accordingly, if the precharge signal 45 is separately supplied via the plurality of image signal lines 6, the data lines 3 connected to the plurality of image signal lines 6 are mutually connected in the precharge period 31. Are charged to different potentials.

  However, according to the liquid crystal device of the present embodiment, the six image signal lines 6 are electrically short-circuited, that is, short-circuited by the short circuit 300 in at least a part of the precharge period 31. For this reason, the time constants of the six image signal lines are aligned regardless of the planar layout on the TFT array substrate 10. That is, the time constants of the six image signal lines 6 are almost the same. Therefore, it is possible to prevent the potential difference after precharging from occurring.

  As a result, it is possible to prevent luminance unevenness or vertical stripes along the data lines from occurring for each of the series of the plurality of image signals VID1 to VID6, and finally high-quality image display can be performed. It becomes.

  4 and 5, in the liquid crystal device according to the present embodiment, the short circuit 300 is synchronized with the precharge timing signal NRG that defines the precharge period 31, that is, only six images in the precharge period 31. The signal line 6 is short-circuited. Therefore, since the N image signal lines 6 are short-circuited during the precharge period, the time constants of the plurality of image signal lines 6 are aligned regardless of the planar layout on the substrate. Accordingly, it is possible to prevent the plurality of data lines 3 connected to the plurality of image signal lines 6 from being charged to different potentials during the precharge period 31.

  In FIG. 4, a short circuit 300 has a source connected to one of a pair of two image signal lines 6 adjacent to each other among six image signal lines 6 and a drain connected to the other. Each of these pairs has a thin film transistor 310 that shorts the pair to each other.

  With this configuration, the gate of the thin film transistor 310 having the source connected to one of the pair of two image signal lines 6 adjacent to each other among the six image signal lines 6 and the drain connected to the other. Is turned on, a pair of two image signal lines 6 adjacent to each other becomes conductive. By selectively turning on the gates of these thin film transistors 310, the pair of two adjacent image signal lines 6 can be selectively short-circuited. Therefore, the time constants of the plurality of image signal lines 6 can be all or selectively aligned regardless of the planar layout on the substrate. Therefore, it is possible to prevent the potential difference after precharging from occurring.

  1 and 4, in the present embodiment, the six image signal lines 6 have mutually different wiring lengths from the external circuit connection terminal 102 to the image signal supply unit 105 on the TFT array substrate 10. Have been drawn around. The image signal supply unit 105 includes a data line driving circuit 101 and a sampling circuit 7.

  Since it is configured in this way, the six image signal lines 6 are laid out in a plane layout with different wiring lengths from the external circuit connection terminal 102 to the image signal supply unit 105 on the TFT array substrate 10. Can do. Further, the six image signal lines 6 are electrically short-circuited by the short circuit 300 in synchronism with the precharge timing signal NRG defining the precharge period 31, that is, only during the precharge period 31. The time constants of the six image signal lines 6 are almost the same regardless of the planar layout on the substrate. Therefore, it is possible to prevent the potential difference after precharging from occurring.

(Second Embodiment)
A liquid crystal device according to a second embodiment will be described with reference to FIGS. FIG. 6 is a diagram having the same concept as FIG. 4 in the second embodiment. FIG. 7 is a diagram having the same concept as in FIG. 5 in the second embodiment. 6 and 7, the same reference numerals are given to the same components as those according to the first embodiment shown in FIGS. 1 to 5, and description thereof will be omitted as appropriate.

  6 and 7, the liquid crystal device according to the second embodiment particularly includes a delay circuit 400 that delays the precharge timing signal NRG that defines the precharge period 31, and the short circuit 300 includes the delayed precharge timing. The six image signal lines 6 are short-circuited in synchronization with the signal NRG2.

  According to the present embodiment, the precharge timing signal NRG1 that defines the precharge period 31 is supplied to the delay circuit 300, and the precharge timing signal NRG1 is delayed by the delay circuit 300. In synchronism with the delayed precharge timing signal NRG2, the short circuit 300 shorts the six image signal lines 6, that is, the precharge period 31 is delayed from the precharge period 31 by a delay period Δt. Short the same length.

  At the end of the precharge period 31, the supply of the precharge signal 45 from the image signal line 6 is completed at the same time. Therefore, at the end of the precharge period 31, fluctuation occurs in the precharge signal 45 of the image signal line 6. The time until this fluctuation is recovered varies depending on the time constants of the plurality of image signal lines 6. Therefore, when the short-circuiting of the plurality of image signal lines 6 is completed at the end of the precharge period 31, the time constants of the plurality of image signal lines 6 are different from each other, so that the time until the fluctuation is recovered also varies. there is a possibility.

  However, according to the present embodiment, the image signal lines 6 are short-circuited at the end of the precharge period 31 because the short circuit is delayed by the same length as the precharge period 31 later than the precharge period 31. Yes. Therefore, the plurality of image signal lines 6 are short-circuited until the fluctuation of the precharge signal 45 of the image signal line 6 at the end of the precharge period 31 is recovered. As a result, it is possible to more effectively prevent the plurality of data lines 3 connected to the plurality of image signal lines 6 from being charged to different potentials during the precharge period 31.

(Third embodiment)
A liquid crystal device according to a third embodiment will be described with reference to FIGS. FIG. 8 is a diagram having the same concept as FIG. 4 in the third embodiment. FIG. 9 is a diagram having the same concept as FIG. 5 in the third embodiment. 8 and 9, the same reference numerals are given to the same components as those according to the first embodiment shown in FIGS. 1 to 5, and description thereof will be omitted as appropriate.

  8 and 9, in the liquid crystal device of the third embodiment, in particular, a short period selection signal SH defining a period including the precharge period 31 is supplied from the outside, and the short circuit 300 selects the supplied short period. In synchronization with the signal SH, the six image signal lines 6 are short-circuited. That is, the same short period as that of the precharge period is made from the time point earlier than the start time of the precharge period 31 to the time point later than the end time of the precharge period 31. For this reason, the precharge signal 45 is caused by the difference in the time constant of the image signal line 6 at the start of the precharge period 31 and at the end of the precharge period 31. It is not affected by fluctuation. Therefore, it is possible to more effectively prevent the plurality of data lines 3 connected to the plurality of image signal lines 6 from being charged to different potentials in the precharge period 31.

(Electronics)
Next, the case where the liquid crystal device which is the above-described electro-optical device is applied to various electronic devices will be described.

  First, a projector using this liquid crystal device as a light valve will be described. FIG. 10 is a plan view showing a configuration example of the projector. As shown in FIG. 10, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G are the same as those of the liquid crystal device described above, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In this dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Accordingly, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display image by the liquid crystal panel 1110G needs to be horizontally reversed with respect to the display images by the liquid crystal panels 1110R, 1110B.

  Note that since light corresponding to the primary colors R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  Next, an example in which the liquid crystal device is applied to a mobile personal computer will be described. FIG. 11 is a perspective view showing the configuration of the personal computer. In FIG. 11, the computer 1200 includes a main body 1204 provided with a keyboard 1202 and a liquid crystal display unit 1206. The liquid crystal display unit 1206 is configured by adding a backlight to the back surface of the liquid crystal device 1005 described above.

  Further, an example in which the liquid crystal device is applied to a mobile phone will be described. FIG. 12 is a perspective view showing the configuration of this mobile phone. In FIG. 12, a mobile phone 1300 includes a reflective liquid crystal device 1005 together with a plurality of operation buttons 1302. In the reflective liquid crystal device 1005, a front light is provided on the front surface thereof as necessary.

  In addition to the electronic devices described with reference to FIGS. 10 to 12, a liquid crystal television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, an electronic notebook, a calculator, a word processor, a work Examples include a station, a videophone, a POS terminal, a device equipped with a touch panel, and the like. Needless to say, the present invention can be applied to these various electronic devices.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and an electro-optical device with such a change, The driving method of the electro-optical device and the electronic apparatus including the electro-optical device are also included in the technical scope of the present invention.

It is a top view which shows the whole structure of the liquid crystal device which concerns on 1st Embodiment of this invention. It is sectional drawing of HH 'of FIG. It is a block diagram showing the principal part structure of the liquid crystal device which concerns on 1st Embodiment of this invention. FIG. 4 is a block diagram illustrating a drive system related to a video precharge operation in the configuration illustrated in FIG. 3. 5 is a timing chart of various signals in the drive system shown in FIG. 4. It is a figure of the same meaning as FIG. 4 in 2nd Embodiment of this invention. It is a figure of the same meaning as FIG. 5 in 2nd Embodiment of this invention. It is a figure of the same meaning as FIG. 4 in 3rd Embodiment of this invention. It is a figure of the same meaning as FIG. 5 in 3rd Embodiment of this invention. It is a top view which shows the structure of the projector which is an example of the electronic device to which the electro-optical apparatus is applied. 1 is a perspective view showing a configuration of a personal computer as an example of an electronic apparatus to which an electro-optical device is applied. It is a perspective view which shows the structure of the mobile telephone which is an example of the electronic device to which the electro-optical apparatus is applied.

Explanation of symbols

  9a ... Pixel electrode, 2 ... Scan line, 3 ... Data line, 6 ... Image signal line, 7 ... Sampling circuit, 10 ... TFT array substrate, 10a ... Image display area, 20 ... Counter substrate, 21 ... Counter electrode, 23 ... Light shielding film, 45 ... Precharge signal, 50 ... Liquid crystal layer, 52 ... Sealing material, 53 ... Frame light shielding film, 71 ... Sampling switch, 101 ... Data line driving circuit, 102 ... External circuit connection terminal, 104 ... Scanning line driving circuit DESCRIPTION OF SYMBOLS 105 ... Image signal supply part 106 ... Vertical conduction terminal, 107 ... Vertical conduction material, 300 ... Short circuit, 310 ... Thin film transistor, 400 ... Delay circuit, LCC ... Counter electrode potential, NRG ... Precharge timing signal, SH ... Short Period selection signal, VID1 to VID6 ... image signal

Claims (12)

A plurality of scanning lines and a plurality of data lines wired in an image display area on the substrate;
A plurality of pixel portions electrically connected to the scanning line and the data line, respectively.
N (where N is a natural number greater than or equal to 2) serial-parallel converted image signals are supplied to drive the plurality of data lines for each data line group including N data lines. N image signal lines to which a precharge signal having a predetermined potential is supplied all at once prior to the image signal;
The image signals supplied via the N image signal lines are supplied for each data line group during the image signal supply period, and the pre-supplied batches are supplied via the N image signal lines. An image signal supply unit that supplies a charge signal to the plurality of data lines in a precharge period preceding the image signal supply period;
An electro-optical device comprising: a short circuit that electrically shorts the N image signal lines to each other in at least a part of the precharge period.   The electro-optical device according to claim 1, wherein the short circuit shorts the N image signal lines in synchronization with a precharge period selection signal that defines the precharge period. A delay circuit for delaying a precharge period selection signal defining the precharge period;
2. The electro-optical device according to claim 1, wherein the short circuit shorts the N image signal lines in synchronization with the delayed precharge period selection signal. A short period selection signal defining a period including the precharge period is supplied from the outside,
2. The electro-optical device according to claim 1, wherein the short circuit shorts the N image signal lines in synchronization with the supplied short period selection signal. The image signal supply unit includes a sampling circuit including a plurality of sampling switches for supplying the image signals respectively supplied from the plurality of image signal lines to the data lines according to a sampling signal;
A data line driving circuit for sequentially supplying the sampling signal for each sampling switch corresponding to the data line group;
5. The electricity according to claim 1, wherein the plurality of sampling switches are turned on collectively in response to a precharge period selection signal that defines the precharge period. Optical device.   The short circuit has a source connected to one of a pair of two adjacent image signal lines of the N image signal lines and a drain connected to the other, and the pair is selectively short-circuited to each other. 6. The electro-optical device according to claim 1, further comprising: a transistor to be operated for each of the pair.   A gate of the transistor includes a precharge period selection signal that defines the precharge period, a delayed signal of the precharge period selection signal, and a short period selection signal that defines a period including the precharge period. The electro-optical device according to claim 6, wherein any one of the signals is input.   2. The N image signal lines are routed on the substrate so as to have different wiring lengths from an external circuit connection terminal to the image signal supply unit. 4. The electro-optical device according to any one of items 1 to 3.   An electronic apparatus comprising the electro-optical device according to claim 1. A plurality of scanning lines and a plurality of data lines wired in an image display area on the substrate, a plurality of pixel portions electrically connected to the scanning lines and the data lines, and N image signal lines, respectively. A driving method for driving an electro-optical device provided,
A precharge step of supplying a precharge signal of a predetermined potential to the plurality of data lines collectively through the N image signal lines in a precharge period preceding the image signal supply period;
In order to drive each data line group including N data lines as a group in the short process of electrically shorting the N image signal lines to each other only during the precharge period and the image signal supply period. And an image signal supplying step of supplying N (where N is a natural number of 2 or more) serial-parallel converted image signals to each of the data line groups via the N image signal lines. A driving method for an electro-optical device. A plurality of scanning lines and a plurality of data lines wired in an image display area on the substrate, a plurality of pixel portions electrically connected to the scanning lines and the data lines, and N image signal lines, respectively. A driving method for driving an electro-optical device provided,
A precharge step of supplying a precharge signal of a predetermined potential to the plurality of data lines collectively through the N image signal lines in a precharge period preceding the image signal supply period;
A short process of electrically shorting the N image signal lines to each other for a period of time that is delayed from the precharge period and equal to the length of the precharge period, and N data lines in the image signal supply period N (where N is a natural number greater than or equal to 2) serial-parallel converted image signals are transferred to the data lines via the N image signal lines. An electro-optical device driving method comprising: an image signal supplying step for supplying each line group. A plurality of scanning lines and a plurality of data lines wired in an image display area on the substrate, a plurality of pixel portions electrically connected to the scanning lines and the data lines, and N image signal lines, respectively. A driving method for driving an electro-optical device provided,
A precharge step of supplying a precharge signal of a predetermined potential to the plurality of data lines collectively through the N image signal lines in a precharge period preceding the image signal supply period;
For each data line group including N data lines as a group in a short process of electrically shorting the N image signal lines to each other only during a period including the precharge period and the image signal supply period. Image signal supply for supplying N (where N is a natural number greater than or equal to 2) serial-parallel converted image signals to each of the data line groups via the N image signal lines. And a driving method for the electro-optical device.

Images