JP2008122747A - Electro-optical device driving circuit, electro-optical device driving method, electro-optical device, and electronic apparatus - Google Patents

Abstract

A potential variation of a pixel portion included in an electro-optical device such as a liquid crystal device is reduced.
A precharge signal generation comprising an effective pixel portion 10e provided in an effective region, a dummy pixel portion 10d provided in a dummy region, an inspection circuit 200, a scanning line driving circuit 104, and a data line driving circuit 101. A circuit is provided, and a precharge signal is selectively supplied to a plurality of data lines 3 during a dummy signal supply period in which a dummy signal is to be supplied to the dummy pixel portion 10d.
[Selection] Figure 3

Description

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

  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. According to Patent Documents 1 to 3, the precharge signal is supplied to the data line at a predetermined timing, thereby improving the display performance of the liquid crystal device and reducing the size of various circuits formed on the substrate.

JP-A-5-73000 JP 10-143113 A JP 2004-246371 A

  However, in the pixel portion that is electrically connected to the same data line and is supplied with an image signal by turning on / off the pixel switching element in accordance with the scanning signal supplied from the adjacent scanning lines, these pixel portions However, there is a technical problem that leakage current is generated between the pixel portions in accordance with the difference in the potential of the image signal supplied to each of them, and the display performance of the electro-optical device is deteriorated. More specifically, for example, each of the two pixel portions arranged adjacent to each other along the data line and electrically connected to the data line is assumed to be collectively in the blanking period related to the image signal. Even when precharging is performed, depending on the potential difference between one pixel portion that maintains a predetermined pixel electrode potential and the other pixel portion, the time during which leakage current can occur between these pixel portions increases or decreases. Will exist.

  Therefore, the present invention has been made in view of the above-described problems. For example, a drive circuit for an electro-optical device capable of performing high-quality image display by performing precharge at an appropriate timing, and its It is an object to provide a driving method, an electro-optical device, and an electronic device.

  In order to solve the above problems, a drive circuit for an electro-optical device according to a first aspect of the present invention includes a plurality of data lines provided on a substrate so as to intersect with each other in a pixel region including an effective region and a dummy region. Driving an electro-optical device comprising a plurality of scanning lines, an effective pixel portion provided corresponding to the intersection of the data line and the scanning line in the effective region, and a dummy pixel portion provided in the dummy region An electro-optical device drive circuit for selectively performing a precharge signal generation circuit for generating a precharge signal having a predetermined potential, and a dummy signal supply period for supplying a dummy signal to the dummy pixel portion. Precharge signal supply means for supplying a precharge signal to the plurality of data lines.

  According to the electro-optical device drive circuit according to the first aspect of the present invention, the dummy region is typically a region provided at the end of the display region on the substrate, and the electro-optical device drive. During the operation of the electro-optical device that displays an image by a circuit, dummy pixel portions that do not substantially contribute to image display are arranged. The effective area is typically an area closer to the center than the dummy area in the display area on the substrate, and is an area in which effective pixel portions contributing to image display are arranged.

  When the electro-optical device driving circuit according to the first aspect of the present invention is operated, the plurality of data lines are connected to the data lines within an effective horizontal scanning period (that is, a period during which image signal sampling is performed). An image signal is supplied. When N image signals subjected to serial-parallel conversion are supplied, N image signals may be supplied for each data line group including a plurality of data lines.

  The precharge signal generation circuit generates a precharge signal having a predetermined potential. Here, the predetermined potential is set to a potential close to the potential of the image signal supplied at a predetermined timing to the effective pixel portion electrically connected to the data line to which the precharge signal is supplied.

  For example, image signals are simultaneously supplied to the plurality of data lines in accordance with driving of an image signal supply unit including a data line driving circuit. In each effective pixel portion, for example, the pixel electrode is selected according to a scanning signal supplied from the scanning line driving circuit via the scanning line, and an image signal is transmitted from the data line via the pixel switching element that performs a switching operation. Supplied to the pixel electrode. Thereby, for example, a liquid crystal element as a display element performs image display based on the supplied image signal.

  The precharge signal supply means precedes the image signal supplied to the effective pixel portion, during a dummy signal supply period in which an image signal that does not substantially contribute to image display (that is, a dummy signal) is to be supplied to the dummy pixel portion. The precharge signal is selectively supplied to the plurality of data lines. Here, “selectively” means that the precharge signal is supplied to the data line to which the effective pixel portion is electrically connected without supplying the precharge signal to the dummy pixel portion. Therefore, a precharge signal is supplied to these data lines during a dummy signal supply period preceding the timing at which an image signal is supplied to the data lines to which the effective pixel portion is electrically connected. By supplying the precharge signal at such timing, the timing at which the precharge signal is supplied to the data line is compared with the case where the data line is precharged in the blanking period preceding the effective horizontal scanning period. It is possible to make it closer to the timing at which the image signal is supplied. Therefore, it is possible to reduce a time during which a leak current can be generated between effective pixel portions electrically connected to an arbitrary data line and adjacent to each other along the data line. More specifically, a potential different from the potential held in the effective pixel portion (that is, the potential held in the pixel electrode of the effective pixel portion in accordance with the image signal) is electrically connected to the effective pixel portion. By reducing the period supplied to the data line, the period during which leakage current occurs in the effective pixel portion can be reduced.

  Therefore, according to the drive circuit for an electro-optical device according to the first aspect of the present invention, since the leakage current in the effective pixel portion can be reduced, display defects caused by the leakage current can be reduced, and a high quality image can be reduced. It is possible to display.

  In one aspect of the drive circuit for an electro-optical device according to the first aspect of the present invention, the image signal supplied via the image signal line electrically connected to the precharge signal supply means is sampled. A sampling circuit including a plurality of sampling switches for supplying the image signal to the data line, and the precharge signal supply means uses a sampling pulse as a reference when the sampling circuit samples the image signal. And an enable circuit for outputting the sampling pulse based on an enable signal supplied via an enable signal supply line and a pulse width narrower than a transfer pulse width, and the enable circuit includes: , Among the plurality of sampling switches in the dummy signal supply period The precharge signal is supplied to a data line electrically connected to the effective pixel portion among the plurality of data lines via a sampling switch other than the sampling switch electrically connected to the dummy pixel portion. May be.

  According to this aspect, the sampling circuit samples the image signal supplied via the image signal line by the plurality of sampling switches and supplies the sampled signal to the data line.

  The precharge signal supply means has an enable circuit. The enable circuit has a pulse width narrower than a width of a transfer pulse that is a base of a sampling pulse that is a reference when the sampling circuit samples the image signal, and is supplied via an enable signal supply line. The sampling pulse is output based on the transfer pulse.

  The enable circuit, during the dummy signal supply period, outputs a signal for switching on the other sampling switches other than the sampling switch electrically connected to the dummy pixel portion among the plurality of sampling switches. A signal that keeps the sampling switch off is supplied to the sampling switch that is supplied to the switch and electrically connected to the dummy pixel portion. A signal supplied from the enable circuit to the other sampling switches is supplied during a dummy signal supply period in which a dummy signal is to be supplied. Therefore, the precharge signal is supplied to the data line to which the effective pixel portion is electrically connected prior to the timing at which the image signal is supplied to the effective pixel portion via another sampling switch. That is, the data line can be precharged at a timing closer to the timing at which the image signal is supplied as compared with the case where the precharge signal is supplied during the blanking period.

  In another aspect of the drive circuit for an electro-optical device according to the first aspect of the present invention, the precharge signal generation circuit is an inspection circuit unit provided for inspecting a circuit unit formed on the substrate. There may be.

  According to this aspect, since the test circuit unit can be shared for precharging the data line, the layout of the circuit unit formed on the substrate can be simplified as compared with the case where a separate precharge circuit is provided. .

  In order to solve the above-described problem, a drive circuit for an electro-optical device according to a second aspect of the present invention includes a plurality of data lines and a plurality of scanning lines provided on the substrate so as to intersect with each other, and the data lines. And an electro-optical device driving circuit for driving an electro-optical device including a plurality of pixel portions provided corresponding to the intersection of the scanning lines, and electrically connected to the plurality of data lines. And an image signal supply circuit unit that supplies image signals to the plurality of pixel units, and is provided separately from the image signal supply unit on the substrate and is electrically connected to the plurality of data lines. The image signal supply circuit unit supplies one image signal to one data line of the plurality of data lines, and then another data to be supplied with another image signal after the one data line. Until the other image signal is supplied to the line. During, and a precharge signal supply means for supplying a precharge signal to the other data lines.

  According to the electro-optical device drive circuit according to the second aspect of the present invention, the image signal supply unit causes the plurality of data lines to fall within the effective horizontal scanning period (that is, the period during which the image signal is sampled). Image signals are sequentially supplied to the data lines. 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 by the data line driving circuit. Then, an image signal is simultaneously supplied to the plurality of data lines according to the sampling signal by the sampling circuit. 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 electrically connected to the data line, and the sampling signal is supplied to the gate. Turns on.

  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.

  The precharge signal supply means is provided separately from the image signal supply unit on the substrate and is electrically connected to the plurality of data lines, and the image signal supply circuit unit includes the plurality of data lines. A period from when one image signal is supplied to one of the data lines to when the other image signal is supplied to another data line to which another image signal is to be supplied next to the one data line In addition, a precharge signal is supplied to the other data line. More specifically, for example, the image signal supply period precedes the i-th image signal supply period for supplying the image signal (i.e., the image signal is supplied to the other data line) and the i-1th image (the image on one data line). In the precharge period after the image signal supply period of the signal supply period), the data lines are precharged by the precharge signal supply means provided separately from the image signal supply unit. The precharge is performed on a plurality of data lines all at once or for each data line according to the precharge timing.

  According to such precharge, precharge can be performed immediately before the image signal is supplied to the pixel portion. For example, a period in which current leakage occurs in the pixel portion as compared with the case where precharge is performed in the blanking period. The display performance of the electro-optical device having the electro-optical device drive circuit can be improved.

  In the electro-optical device drive circuit according to a second aspect of the present invention, the precharge signal supply means responds to a shift register that sequentially outputs transfer signals and a sampling circuit drive signal generated based on the transfer signals. And a sample and hold circuit including a sampling switch for supplying the precharge signal to the other data line.

  According to this aspect, the shift register included in the precharge signal supply unit is connected to the data line immediately before the transfer signal for supplying the image signal to each data line is supplied by the shift register included in the image signal supply unit, for example. Precharging can be performed. The precharge signal supply means has the same configuration as the predetermined circuit section provided in the image signal supply section, and is opposite to one end of the data line where the image signal supply section is electrically connected. Is electrically connected to the other end.

  In order to solve the above problems, a driving method of an electro-optical device according to a third aspect of the present invention includes a plurality of data lines provided on a substrate so as to intersect with each other in a pixel region including an effective region and a dummy region. An electro-optical device comprising a plurality of scanning lines, an effective pixel portion provided corresponding to an intersection of the data line and the scanning line in the effective region, and a dummy pixel portion provided in the dummy region. A driving method of an electro-optical device for driving, wherein a precharge signal generation step of generating a precharge signal of a predetermined potential and a dummy signal supply period for supplying a dummy signal to the dummy pixel portion are selectively performed A precharge signal supplying step of supplying the precharge signal to the plurality of data lines.

  According to the driving method of the electro-optical device according to the third aspect of the present invention, similarly to the electro-optical device driving circuit according to the first aspect of the present invention described above, current leakage in the effective pixel portion can be reduced, The display performance of the electro-optical device can be improved.

  In order to solve the above problems, a driving method of an electro-optical device according to a fourth aspect of the present invention includes a plurality of data lines and a plurality of scanning lines provided on a substrate so as to intersect with each other, and the data lines and An electro-optical device driving method for driving an electro-optical device including a plurality of pixel portions provided corresponding to intersections of the scanning lines, the method being electrically connected to the plurality of data lines An image signal supply step for supplying an image signal to the plurality of pixel units by an image signal supply circuit unit; and provided on the substrate separately from the image signal supply unit and electrically connected to the plurality of data lines The image signal supply circuit unit supplies one image signal to one data line among the plurality of data lines by the precharge signal supply means, and then another image signal next to the one data line. Should be supplied The time to the other image signals to the data lines are supplied, and a precharge signal supplying step for supplying a precharge signal to the other data lines.

  According to the driving method of the electro-optical device according to the fourth aspect of the present invention, similarly to the above-described driving circuit for the electro-optical device according to the second aspect of the present invention, current leakage in the pixel portion can be reduced. It is possible to improve the display performance of the optical device.

  An electro-optical device according to a fifth aspect of the present invention includes the above-described electro-optical device drive circuit according to the first or second aspect of the present invention.

  According to the electro-optical device according to the fifth aspect of the present invention, since the electro-optical device drive circuit according to the first or second aspect of the present invention is provided, an electro-optical device having excellent display performance is provided. can do. Therefore, the electro-optical device according to the fifth aspect of the present invention can perform high-quality display.

  In order to solve the above problems, an electronic apparatus according to a sixth aspect of the present invention includes the above-described electro-optical device according to the fifth aspect of the present invention.

  According to the electronic apparatus according to the present invention, since the electro-optical device according to the present invention described above is provided, a projection display device, a mobile phone, an electronic notebook, a word processor, and a viewfinder type capable of high-quality display. Alternatively, various electronic devices such as a monitor direct-view video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized. In addition, as an electronic apparatus according to the present invention, for example, an electrophoretic device such as electronic paper can be realized.

  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 TFT active matrix driving type liquid crystal device with a built-in driving circuit, which is an example of an electro-optical device according to the fifth aspect of the present invention, will be described as an example.

<First Embodiment>
First, referring to FIGS. 1 to 6, the electro-optical device drive circuit according to the first invention of the present invention, the electro-optical device drive method according to the third invention, and the electro-optical device according to the fifth invention. Each embodiment of the apparatus will be described.

<1-1: Overall Configuration of Electro-Optical Device>
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 II-II ′ of FIG.

  1 and 2, in the liquid crystal device 1 according to the present embodiment, a TFT array substrate 10 and a counter substrate 20 are disposed 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 around the image display region 10a which is a typical example of the “pixel region” of the present invention. They are bonded to each other by a sealing material 52 provided in a sealing region located in the area.

  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 9 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. Then, 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 9.

  The TFT array substrate 10 may be configured using a transparent substrate such as quartz or plastic, or may be configured using a semiconductor substrate made of single crystal silicon or a single crystal silicon compound.

  In the case where a semiconductor such as single crystal silicon is used for the TFT array substrate 10, a transistor can be formed as an element for pixel switching.

<1-2: Configuration of Main Part of Electro-Optical Device>
Next, the main configuration of the liquid crystal device will be described with reference to FIGS. FIG. 3 shows the configuration of the main part of the liquid crystal device. FIG. 4 shows a circuit system related to shaping of a transfer signal in the configuration shown in FIG. FIG. 5 is a diagram having the same concept as in FIG. 4 according to the first modification. In FIG. 4, for convenience of explanation, one image signal VID is shown.

  In FIG. 3, a liquid crystal device 1 includes 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) facing each other with a liquid crystal layer interposed therebetween. The voltage applied to the pixel electrodes 9 partitioned and arranged in 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. This liquid crystal device adopts a TFT active matrix drive system, and a plurality of pixel electrodes 9 arranged in a matrix and a plurality of scanning lines 2 and a plurality of scanning lines 2 arranged in a matrix are arranged in a pixel display region 10a of the TFT array substrate 10. A data line 3 is formed, and a pixel portion corresponding to the pixel is constructed.

  The image display area 10a includes an effective area 10e that is an area from the center of the image display area 10a and a dummy area 10d that is an area near the edge of the image display area 10a. Each of the plurality of effective pixel portions 70e has a pixel electrode 9e, and is formed in a matrix in the effective region 10e. Each of the plurality of dummy pixel portions 70d has a pixel electrode 9d and is formed in the dummy region 10d. The effective pixel portion 70 e is a pixel portion that substantially contributes to image display during the operation of the liquid crystal device 1, and an image signal is supplied via the data line 3. The dummy pixel portion 70 d is a pixel portion that does not substantially contribute to image display during the operation of the liquid crystal device 1, and an image signal as a dummy signal is supplied to the dummy pixel portion 70 d via the data line 3.

  Although not shown here, between each pixel electrode 9 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 the capacitor 9 is formed. In addition, a drive circuit such as the data line drive circuit 101 and an external circuit connection terminal 102 are formed in the peripheral area of the image display area 10a.

  The liquid crystal device 1 includes an inspection circuit 200, a scanning line driving circuit 104, and a data line driving circuit 101, which are examples of the “precharge signal generation circuit” of the present invention.

  The data line driving circuit 101 includes a shift register 51, an enable circuit 55 which is an example of the “precharge signal supply unit” of the present invention, and a sampling circuit 7.

  The shift register 51 receives a transfer signal Pi (i = 1) from each stage based on an X-side clock signal CLX (and its inverted signal CLXB) and a shift register start signal DX having a predetermined period input into the data line driving circuit 101. ,..., N) are sequentially output.

  The enable circuit 55 shapes the transfer signal Pi (i = 1,..., N) based on the enable signal during the operation of the liquid crystal device 1, and finally the sampling circuit drive signal Si (i) based on that. = 1,..., N).

  In FIG. 4, the enable circuit 55 includes two stages of an AND circuit 55A and an OR circuit 55D. The AND circuit 55A is one of the transfer signals Pi (i = 1,..., N) input from the shift register 51 and enable signals ENB1 to ENB4 supplied from each of the four enable supply lines 81. A logical product of the two is output as a sampling circuit drive signal Si (i = 1,..., N). The OR circuit 55D is provided at the subsequent stage of the AND circuit 55A, and an NRG signal (Noise Reduction Gate) that defines a precharge period is input from the output of the AND circuit 55A and each of the four enable supply lines 81. When at least one of these signals is input, “High” is output. The NRG signal is supplied from an image processing circuit outside the TFT array substrate 10 via the enable supply line 81 and the external circuit connection terminal 102. The waveform of the transfer signal Pi (i = 1,..., N) is trimmed based on the waveforms of the enable signals ENB1 to ENB4 having a narrower pulse width, and the pulse width is limited to the pulse width of the enable signal.

  As will be described in detail later, the enable circuit 55 supplies an image signal (that is, a dummy signal) that does not substantially contribute to image display to the dummy pixel unit 70d prior to the image signal supplied to the effective pixel unit 70e. In order to supply the precharge signal to the plurality of data lines 3 during the dummy signal supply period to be performed, the plurality of sampling switches 71 included in the sampling circuit 7 are selectively switched on and off.

  The enable circuit 55 can also be configured with a transmission gate. That is, a transmission gate in which the enable signal is input to the gate and the transfer signal Pi is input to the source (or vice versa) may be used.

  The sampling circuit 7 samples the image signal VID supplied to the image signal line 6 in accordance with a sampling circuit drive signal Si (i = 1,..., N) that is a reference clock signal, and uses each as a data signal. Applied to the data line 3. For example, as shown in FIG. 4, the sampling circuit 7 includes a plurality of sampling switches 71 each composed of a P-channel or N-channel single-channel TFT or a complementary TFT.

  Here, for the sake of simplicity of explanation, only one image signal line 6 is provided, and any sampling switch 71 is supplied with the image signal VID from the image signal line 6. However, the image signal is serial-parallel. Development (that is, phase expansion) may be performed. As shown in FIG. 5 as a first modification, when an image signal is serially / parallel-developed into six phases of image signals VID1 to VID6, these image signals are sampled through a sampling circuit 7 via six image signal lines. Is input. When parallel image signals obtained by converting serial image signals are simultaneously supplied to a plurality of image signal lines, image signals can be input to the data lines 3 for each group, and the drive frequency can be suppressed.

  The scanning line drive circuit 104 scans a plurality of pixel electrodes 9 arranged in a matrix in the array direction of the scanning lines 2 using data signals and scanning signals, and a Y-side clock signal CLY that is a reference clock for applying scanning signals. A scanning signal generated based on (and its inverted signal CLYB) and the shift register start signal DY is sequentially applied to the plurality of scanning lines 2. In that case, a voltage is simultaneously applied to each scanning line 2 from both ends.

  Various timing signals such as the clock signal CLX are generated by a timing generator (not shown) and supplied to each circuit on the TFT array substrate 10. Further, power supply voltages VDDX, VDDY and the like necessary for driving each drive circuit are also supplied from an external circuit. Further, the counter electrode potential LCC is supplied from the external circuit to the signal line drawn from the vertical conduction terminal 106. The counter electrode potential LCC is supplied to the counter electrode 21 through the vertical conduction terminal 106. The counter electrode potential LCC is a reference potential of the counter electrode 21 for appropriately holding the potential difference from the pixel electrode 9 and forming a liquid crystal storage capacitor.

  5, in the liquid crystal device according to the present embodiment, at the time of driving, the image signal VID is supplied to the image signal line 6 and further supplied to the image signal supply unit 110. In response to the supply of the image signal VID, the image signal supply unit 110 sequentially supplies the plurality of data lines 3 with the image signal VID for each data line group Di. That is, an image signal supply period for supplying the image signal VID is assigned to each data line group Di.

<1-3: Driving Method of Electro-Optical Device>
Next, the precharge performed on the effective pixel unit 70e will be described in detail with reference to FIGS. FIG. 6 is a timing chart showing the precharge operation in the liquid crystal device of this embodiment.

  As shown in FIG. 3, the image signal supply circuit unit 110 includes a data line driving circuit 101 and an enable circuit 55 that constitute an example of the “precharge signal supply unit” according to the present invention, and a sampling circuit 7. Has been. The enable circuit 55 sequentially supplies a sampling circuit drive signal Si for each sampling switch 71 corresponding to the data line group Di. The sampling circuit 7 simultaneously supplies the plurality of data lines 3 with the image signal VID for each data line group Di according to the sampling circuit drive signal Si. Therefore, the data lines 3 belonging to the same data line group Di are driven simultaneously.

  When the data line 3 is driven in this way, in each effective pixel portion 70e, the pixel electrode 9e is selected according to the scanning signal supplied from the scanning line driving circuit 104 via the scanning line 2, and the switching operation is performed. The image signal VID is supplied from the data line 3 to the pixel electrode 9e through the pixel switching element to be performed. Thereby, the liquid crystal element as a display element performs image display based on the supplied image signal VID. Hereinafter, in order to simplify the description, a case where the pixel portion corresponding to the enable signal ENB1 is the dummy pixel portion 70d will be described as an example.

  3, 4, and 6, the enable circuit 55 includes a dummy signal supply period preceding the effective display period, that is, a dummy pixel unit within an effective horizontal scanning period (that is, a period during which image signal sampling is performed). During the period when the enable signal ENB1 supplied corresponding to 70d is supplied to the enable circuit 55, a precharge signal is supplied to the effective pixel unit 70e in a lump.

  Here, the enable signal ENB1 is supplied as a Low signal so that the sampling switch 71 electrically connected to the dummy pixel unit 70d is not switched from the on state to the off state. That is, ENB1 in the dummy signal supply period is supplied as a signal having a potential different from that of enable signals ENB2 to n supplied as High signals for switching the sampling switch 71 from the OFF state to the ON state. The dummy signal supply period is a period preceding the effective display period in which the image signal is actually supplied to each data line 3 in the effective horizontal scanning period, and coming after the blanking period.

  Among the plurality of enable signal supply lines 81, the enable signal line 81 that supplies ENB1,..., N to the enable circuit 55 receives the NRG signal (NRG2,. , N). The enable circuit 55 supplies a sampling signal to the sampling switch 71 corresponding to the effective pixel unit 70e according to the NRG signals NRG2,. Thereby, in the dummy signal supply period, the sampling switch 71 electrically connected to the effective pixel unit 70e is switched from the off state to the on state. At this time, a precharge signal having a predetermined potential is supplied from the inspection circuit 200 to the image signal line 6. The sampling switch 71 switched to the on state samples the precharge signal and supplies it to the effective pixel unit 70e. Thereby, the potential of the pixel electrode 9e of the effective pixel unit 70e to which the image signal has already been supplied is the potential of the other effective pixel unit 70e electrically connected to the effective pixel unit 70e through the common data line 3. It is possible to reduce fluctuation due to the influence of.

  More specifically, the effective pixel portion is an effective pixel portion that is electrically connected to the common data line 3 and has an effective pixel portion that is turned on and off by a different scanning signal. The occurrence of current leakage between these effective pixel portions due to the difference in potential between the pixel electrodes 9e can be reduced. As a result, the potential of the pixel electrode corresponding to the image signal in each pixel electrode 9e is maintained within the effective horizontal scanning period, and the reduction in image quality due to the potential variation of the pixel electrode 9e is reduced. it can.

  In addition, according to such a driving method, each effective pixel unit 70e has a pixel included in the effective pixel unit 70e, as compared with the conventional precharge method in which a precharge signal is supplied to the data line in the blanking period. Since the period of electrical connection to the data line 3 to which a signal having a potential different from the potential of the electrode 9e is supplied can be shortened, the potential fluctuation in the effective pixel portion 70e can be more effectively reduced.

  Note that after the precharge signal is supplied to the effective pixel unit 70e, enable signals ENB2 to n are supplied to the enable circuit 55 according to the timing at which the image signal should be supplied to each effective pixel unit 70e. Each of the sampling signals Si whose waveform is shaped so that the pulse width is narrower than that of the transfer signal Pi by the enable signal is supplied to the corresponding sampling switch 71, and the image signal is passed through these sampling switches 71 to the effective pixel portion. 70e and a desired image is displayed in the image display area 10a.

  In the present embodiment, a signal sampled as a precharge signal is supplied from the inspection circuit 200 to the image signal 6. Therefore, there is an advantage that the layout of the circuit portion formed on the TFT array substrate 10 can be simplified as compared with the case where a separate precharge circuit is provided.

<Second Embodiment>
Next, the electro-optical device drive circuit according to the second invention of the present invention and the electro-optical device drive method according to the fourth invention of the present invention will be described with reference to FIGS. In the following, common reference numerals are assigned to portions common to the first embodiment, and detailed description thereof is omitted.

<2-1: Main configuration of electro-optical device>
With reference to FIG. 7, a main configuration of the electro-optical device including the drive circuit for the electro-optical device according to the present embodiment will be described. FIG. 7 is a block diagram illustrating a circuit configuration of a main part of a liquid crystal device which is an example of the electro-optical device according to the present embodiment.

  In FIG. 7, the liquid crystal device according to the present embodiment is provided on the TFT array substrate 10 on the opposite side of the image signal supply circuit unit 110 via the image display region 10a. The present embodiment is characterized in that it includes a shift register 51a, a sample hold circuit 7a, and a precharge signal generation circuit 201 that constitute an example of the “precharge signal supply means”.

  The image signal supply circuit 110 generates a sampling signal based on the transfer signal supplied from the shift register 51 to the enable circuit 55 and the enable signal supplied to the enable circuit 55 during the operation of the liquid crystal device. The image signal is supplied to each data line 3 through a plurality of sampling switches 71 that are switched from the off state to the on state by the above. Thereby, the orientation control of the liquid crystal in each pixel unit 70 is performed according to the image signal, and a desired image is displayed in the image display area 10a.

  The sample hold circuit 7 a is electrically connected to the end opposite to the end to which the sampling circuit 7 is electrically connected, of both ends of the data line 3. The precharge signal generation circuit 201 is electrically connected to the sample hold circuit 7a, and supplies a precharge signal sampled by the sample hold circuit 7a to the sample hold circuit 7a. The shift register 51a is electrically connected to the sample hold circuit 7a, and supplies the sampling signal to the sample hold circuit 7a at a predetermined timing so that the precharge signal is sampled by the sample hole circuit 7a.

  According to the drive circuit included in the liquid crystal device according to the present embodiment, as described in detail later, the image signal is transmitted to each pixel unit by the operations of the shift register 51a, the sample hold circuit 7a, and the precharge signal generation circuit 201. A precharge signal is supplied to the data line 3 immediately before. Therefore, in accordance with the difference in potential of the pixel electrodes 9a maintained in response to the supply of the image signal, the potential fluctuations generated in the pixel electrodes 9a can be reduced, and the display quality of the liquid crystal device can be improved.

<2-2: Driving method of electro-optical device>
Next, a driving method performed by the electro-optical device driving circuit according to the present embodiment will be described with reference to FIGS. FIG. 8 is a timing chart showing the precharge operation in the liquid crystal device according to the present embodiment.

  8, in the liquid crystal device according to the present embodiment, enable signals ENB1 to ENBn are supplied to the enable circuit 55 from an external circuit via an enable signal line 81. The enable signals ENB1 to ENBn have a pulse width d1 that is narrower than the width of the transfer pulse Pi that is the basis of the sampling circuit drive signal Si that is a reference when the sampling circuit 7 samples the image signal VID. The enable circuit 55 limits the width of the transfer pulse Pi according to the enable signals ENB1 to ENB4 to obtain the sampling circuit drive signal Si. That is, the enable circuit 55 takes the logical product of the enable signals ENB1 to ENBn and the transfer pulse Pi to obtain a sampling circuit drive signal having a pulse width d1 of the enable signals ENB1 to ENBn, which is narrower than the width of the transfer pulse Pi. Si is generated.

  The sampling and holding circuit 7a receives sampling signals Sai (i = 1,..., N, n) from the shift register 51a at the timing when the enable signals ENB1 to ENBn are supplied via the enable signal supply line 81. ; Natural number) is supplied. More specifically, an enable signal that defines the timing at which the image signal is supplied to the i-th data line 3, that is, a sampling circuit drive signal Si that defines the timing at which the image signal is supplied to the i-th data line 3 is supplied. Immediately before the sampling, the sampling signal Sai is supplied to the sample hold circuit 7a.

  Here, since the sample hold circuit 7a has a circuit configuration similar to that of the sampling circuit 7, the signal P ′ below the precharge signal supplied via the precharge signal supply line 82 is the sampling signal. Sampling is performed by the sample hole circuit 7a according to Sai. Accordingly, the signal P ′ is supplied to the data line 3 as the precharge signal Pcs. Therefore, the data line 3 is precharged immediately before the image signal to be supplied to the data line 3 is supplied. Such supply of the precharge signal Pcs is performed to all the data lines 3 in one effective scanning period.

  Therefore, while precharging has been performed collectively using the blanking period so far, immediately before the image signal is supplied to the data line 3 in the effective horizontal scanning period (period during which the image signal is sampled). Can be precharged. As a result, the potential of the pixel electrode 9a is different from the potential of the other pixel electrode 9a (that is, the potential of the pixel electrode of the pixel portion to which the image signal is supplied during the effective scanning period) as compared with the case where precharging is performed in the blanking period. Fluctuation due to the potential of the image can be reduced, and high-quality image display can be performed.

  As described above, according to the drive circuit of the electro-optical device in each of the first embodiment and the second embodiment, and the drive method executed by such a drive circuit, the pixel electrode is applied according to the image signal. The variation of the maintained pixel electrode potential can be reduced, and the display performance of an electro-optical device such as a liquid crystal device can be improved.

<3: Electronic equipment>
Next, a case where the above-described liquid crystal device which is an 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. 9 is a plan view showing a configuration example of the projector. As shown in FIG. 9, a projector 1100 includes a lamp unit 1102 made up 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.

  In addition to the liquid crystal device described in the above embodiment, the present invention is not limited to a reflective liquid crystal device (LCOS), a plasma display (PDP), a field emission display (FED, SED) in which elements are formed on a silicon substrate. It can also be applied to organic EL displays, digital micromirror devices (DMD), electrophoresis apparatuses, and the like.

It is a top view which shows the structure of the liquid crystal device which concerns on 1st Embodiment. It is sectional drawing in the II-II 'line of FIG. FIG. 3 is a block diagram illustrating a circuit configuration of a main part of the liquid crystal device according to the first embodiment. FIG. 4 is a block diagram showing a circuit system related to shaping of a transfer signal in the configuration shown in FIG. 3. It is a figure of the same meaning as FIG. 4 which concerns on a 1st modification. 6 is a timing chart illustrating a precharge operation in the driving method of the electro-optical device according to the first embodiment. FIG. 10 is a block diagram illustrating a circuit configuration of a main part of an electro-optical device according to a second embodiment. 10 is a timing chart illustrating a precharge operation in the liquid crystal device according to the second embodiment. 1 is a plan view illustrating a configuration of a projector that is an example of an electronic apparatus according to an embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal device, 7 ... Sampling circuit, 7a ... Sample hold circuit, 51, 51a ... Shift register, 55 ... Enable circuit, 200 ... Inspection circuit, 201 ... Pre Charge signal generation circuit

Claims (9)

A plurality of data lines and a plurality of scanning lines provided on a substrate so as to intersect with each other in a pixel area including an effective area and a dummy area, and provided corresponding to the intersection of the data lines and the scanning lines in the effective area. A drive circuit for an electro-optical device for driving an electro-optical device including the effective pixel portion and a dummy pixel portion provided in the dummy region,
A precharge signal generation circuit for generating a precharge signal of a predetermined potential;
An electro-optical device comprising: precharge signal supply means for selectively supplying the precharge signal to the plurality of data lines during a dummy signal supply period in which a dummy signal is to be supplied to the dummy pixel portion. Drive circuit. A sampling circuit including a plurality of sampling switches for sampling the image signal supplied via the image signal line electrically connected to the precharge signal supply means to supply the image signal to the data line; ,
The precharge signal supply means has a pulse width narrower than the width of a transfer pulse that is a source of a sampling pulse that is a reference when the sampling circuit samples the image signal, and is supplied via an enable signal supply line. And an enable circuit that outputs the sampling pulse based on the transfer pulse and
In the dummy signal supply period, the enable circuit includes the sampling switches other than the sampling switches that are electrically connected to the dummy pixel unit, and the data lines out of the plurality of data lines. The electro-optical device circuit according to claim 1, wherein the precharge signal is supplied to a data line electrically connected to an effective pixel portion. The electro-optical device circuit according to claim 1, wherein the precharge signal generation circuit is an inspection circuit unit provided for inspecting a circuit unit formed on the substrate. An electro-optical device including a plurality of data lines and a plurality of scanning lines provided on a substrate so as to intersect with each other, and a plurality of pixel portions provided corresponding to the intersection of the data lines and the scanning lines. A drive circuit for an electro-optical device for driving,
An image signal supply circuit unit that is electrically connected to the plurality of data lines and supplies an image signal to the plurality of pixel units;
Provided separately from the image signal supply unit on the substrate and electrically connected to the plurality of data lines, and the image signal supply circuit unit is connected to one of the plurality of data lines. The other data line is supplied during a period from when the other image signal is supplied to another data line to which another image signal is to be supplied after the one data line. And a precharge signal supply means for supplying a precharge signal to the electro-optical device drive circuit. The precharge signal supply means includes:
A shift register that sequentially outputs transfer signals;
5. A sample hold circuit including a sampling switch that supplies the precharge signal to the other data line in accordance with a sampling circuit drive signal generated based on the transfer signal. 6. Drive circuit for electro-optical device. A plurality of data lines and a plurality of scanning lines provided on the substrate so as to intersect with each other in a pixel area including an effective area and a dummy area, and corresponding to the intersection of the data lines and the scanning lines in the effective area. A driving method of an electro-optical device for driving an electro-optical device provided with an effective pixel portion provided and a dummy pixel portion provided in the dummy region,
A precharge signal generating step for generating a precharge signal of a predetermined potential;
And a precharge signal supply step of selectively supplying the precharge signal to the plurality of data lines in a dummy signal supply period in which a dummy signal is to be supplied to the dummy pixel portion. Driving method. An electro-optical device including a plurality of data lines and a plurality of scanning lines provided on a substrate so as to intersect with each other, and a plurality of pixel portions provided corresponding to the intersection of the data lines and the scanning lines. A driving method of an electro-optical device for driving,
An image signal supply step of supplying an image signal to the plurality of pixel units by an image signal supply circuit unit electrically connected to the plurality of data lines;
The image signal supply circuit unit is provided on one of the plurality of data lines by a precharge signal supply unit provided separately from the image signal supply unit on the substrate and electrically connected to the plurality of data lines. In a period from the time when one image signal is supplied to the other data line to the time when the other image signal is supplied to the other data line to which another image signal is to be supplied next to the one data line, And a precharge signal supplying step of supplying a precharge signal to the other data line. An electro-optical device comprising the electro-optical device drive circuit according to claim 1. An electronic apparatus comprising the electro-optical device according to claim 8.

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