JP4492444B2 - Electro-optical device driving circuit and driving method, electro-optical device, and electronic apparatus - Google Patents

Description

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

  As an example of an electro-optical device driven by this type of drive circuit, Patent Document 1 or 2 corresponds to data lines and scanning lines wired vertically and horizontally in an image display area on a substrate, and their intersections. A liquid crystal device having a liquid crystal panel including a pixel portion formed in this manner is disclosed. In this liquid crystal panel, each pixel portion is provided with a liquid crystal element and a pixel switching element that is electrically connected to the data line and the scanning line and controls the switching of the liquid crystal element. The pixel switching element is configured using, for example, an N-channel or P-channel thin film transistor (Thin Film Transistor; hereinafter referred to as “TFT” as appropriate) as a single channel type. At the time of driving such a liquid crystal panel, the liquid crystal element is AC driven based on an image signal having either a positive polarity or a negative polarity in order to prevent deterioration of the liquid crystal due to application of a DC component. .

  According to Patent Document 1, when an image is displayed on a liquid crystal panel in which the number of scanning lines is larger than the number of scanning lines of a video source, the driving circuit performs high-speed scanning that is twice the normal operation of the display period in the blanking period. Done. According to Patent Document 2, the drive circuit controls the input / output characteristics of the image signal according to the type of the liquid crystal panel.

Japanese Patent Laid-Open No. 9-269553 JP 2002-221940 A

  Here, when the liquid crystal element is AC-driven, positive and negative image signals are alternately supplied to the data lines in some form. Then, when the image signal has any polarity, the gate-source voltage in the pixel switching TFT becomes a value relatively close to the threshold voltage. That is, each TFT is likely to leak when it is off, and particularly light leaks due to light entering the channel region of the TFT during operation. In particular, when the voltage on the data line that has finished supplying the image signal voltage to one pixel electrode changes when the image signal voltage is supplied to another pixel electrode connected to the same data line, A leak current due to a leak through a thin TFT occurs in one pixel electrode. Therefore, vertical crosstalk occurs between pixel columns connected to the same data line via TFTs. However, for example, in a pixel electrode that holds a black display potential or a pixel electrode that holds a white display potential, a potential change (decrease or rise) due to a leak is caused by the applied voltage-gradation characteristics of a general liquid crystal element. Therefore, the change in gradation is not so obvious. As a result, it is difficult for the vertical crosstalk to be recognized by human eyes. Alternatively, for example, when displaying a black line extending in the horizontal direction, the entire cross-section of the display screen may change in gradation uniformly due to the above-described vertical crosstalk. Therefore, the vertical crosstalk is not so high as to be visually recognized by human eyes.

  On the other hand, when a black pattern such as a black dot or a black block is displayed as a display image in a halftone background as a display image in the image display area, the voltage corresponding to the halftone is maintained when the above-described leakage current occurs. In the pixel portion, the gradation changes relatively greatly due to the change in the voltage. Moreover, since the gradation is different between the left and right adjacent halftone areas, the vertical crosstalk is remarkably recognized by human eyes. In the specification of the present application, the pixels connected to the same data line are electrically connected to each other via the TFT and the data line, including both the vertical crosstalk that is not easily seen and the vertical crosstalk that is easily seen as described above. The term “broad-direction vertical crosstalk” is used as appropriate in the sense that it has an influence on each other, and the meaning that vertical crosstalk that is easily or noticeably visible affects each other on the display image. Is referred to as “vertical crosstalk in a narrow sense” as appropriate. In the above-described electro-optical device, particularly when vertical crosstalk in a narrow sense occurs, there is a problem that the quality of a display image is deteriorated.

  The present invention has been made in view of the above problems, and a driving circuit and a driving method capable of performing high-quality image display by reducing vertical crosstalk in a display image displayed in an electro-optical device, It is another object of the present invention to provide an electro-optical device including such a drive circuit and various electronic devices including the electro-optical device.

In order to solve the above-described problem, the drive circuit of the electro-optical device according to the invention electrically connects the plurality of data lines and the plurality of scanning lines, the display element, the data lines, and the scanning lines in the image display region on the substrate. And a driving circuit for driving an electro-optical device including a plurality of pixel portions each including a single-channel thin film transistor for controlling the switching of the display element, and a scanning signal for each of the plurality of scanning lines. a scanning line driving circuit for supplying, of the positive polarity and negative polarity with respect to (i) a reference potential, the thin film transistor has the positive polarity when Ru N-channel type der, the thin film transistor is a P-channel type having said negative polarity to the cases, in the image display area and having an image signal and (ii) the image signal is different from the polarity for displaying a display image on the image display area An image signal supply circuit that supplies a solid signal for displaying a solid image of a specific color to each of the plurality of pixel portions via the data line alternately in a predetermined cycle.

  In the electro-optical device driven by the driving circuit of the present invention, the plurality of pixel portions are arranged corresponding to the intersections of the scanning lines and the data lines wired vertically and horizontally. Each pixel portion includes a display element and a TFT as a pixel switching element that controls switching of the display element. As this TFT, an N-channel type or a P-channel type is used.

  When the electro-optical device is driven, each scanning line is driven line-sequentially from the top to the bottom of the image display region, for example, by supplying a scanning signal from the scanning line driving circuit. In each pixel unit, a scanning signal is supplied to the pixel switching element via a corresponding scanning line. The pixel switching element is turned on during a period in which the scanning signal is supplied to the corresponding scanning line.

  Further, the image signal is sequentially supplied from the image signal supply circuit to, for example, one or a plurality of data lines among the plurality of data lines. Then, an image signal is supplied from the data line to the display element through the pixel switching element that is turned on when the scanning signal is supplied from the scanning line. In this way, each scanning line is driven based on the scanning signal, whereby a display image is displayed in the image display area.

  Further, a solid signal is supplied to each data line from the image signal supply circuit. Similarly to the image signal, the solid signal may be sequentially supplied to one or a plurality of data lines among the plurality of data lines, or may be supplied to each data line collectively. A solid signal is supplied from the data line to the display element through the pixel switching element that is turned on when the scanning signal is supplied from the scanning line. In this way, each scanning line is driven based on the scanning signal, so that a solid image of a specific color is displayed in the image display area. Here, the “solid image of a specific color” means one screen that is displayed in the image display area and is filled with a specific color. For example, the image signal circuit supplies, as a solid signal, a black signal for displaying a black image, which is one screen filled with black, as a solid image of a specific color. In addition, the “solid image of a specific color” may be a screen filled with a color near black, or a blackish color, and further gray.

  For example, such a display image and a black image that is a solid image are alternately displayed for each screen such as a frame image. Alternatively, these images are displayed according to partial areas of the image display area (for example, in the first half of one field period to be described later, the upper half of the display image is displayed in the upper half of the image display area and the image display area The lower half of the black image is displayed in the lower half), and these areas are displayed in a manner that they are interchanged with each other (for example, the display image is displayed in the lower half of the image display area in the latter half of one field period described later). And the upper half of the black image is displayed in the upper half of the image display area). Alternatively, each of these images is displayed by area scanning in one of two partial areas (for example, upper half and lower half) (for example, displayed by area scanning in the upper half in the first half of one field period described later). While the image is displayed, a black image is displayed by scanning the region in the lower half simultaneously) and these are displayed in a predetermined cycle (for example, in the latter half of one field period to be described later, While a black image is displayed by area scanning, a display image is formed by area scanning in the lower half simultaneously.) Alternatively, these images are alternately displayed in a comb-teeth pattern every other line (for example, in the first half of one field period, the odd lines of the display image are displayed on the odd lines and the black image is striped on the even lines. And these are displayed in a predetermined cycle (for example, in the second half of one field period, the even lines of the display image are displayed on the even lines and the black image is displayed on the odd lines in a stripe pattern. )

  Here, for example, when an N-channel TFT is used as the pixel switching element, a black signal is supplied as a “negative polarity” voltage as a solid signal from the image signal supply circuit. Then, in the pixel portion corresponding to the data line to which the black signal is supplied, the voltage between the gate and the source of the pixel switching element becomes a value close to the threshold voltage. It becomes easy to generate off current such as. Conversely, when an N-channel TFT is used as the pixel switching element, the image signal is supplied as a “positive polarity” voltage from the image signal supply circuit. Then, in the pixel portion corresponding to the data line to which the image signal is supplied, the voltage between the gate and the source of the pixel switching element is relatively far from the threshold voltage, and thus an off current such as a light leakage current is generated. It becomes difficult.

  On the other hand, when a P-channel TFT is used as the pixel switching element, for example, a black signal is supplied as a “positive” voltage from the image signal supply circuit as a solid signal. In this case, as in the case of using the above-described N-channel TFT, off current such as light leakage current is likely to occur in the pixel portion corresponding to the data line supplied with the black signal. Conversely, when a P-channel TFT is used as the pixel switching element, the image signal is supplied as a “negative polarity” voltage from the image signal supply circuit. In this case, as in the case of using the above-described N-channel TFT, off current such as light leakage current is hardly generated in the pixel portion corresponding to the data line supplied with the image signal.

  Therefore, by unifying the polarity of the image signal to one of those in which the vertical crosstalk in the broad sense is less likely to occur, a situation in which the vertical crosstalk in the broad sense is likely to occur does not occur for the display image in the present invention. Therefore, in this case, for example, even when black dots or black blocks are displayed in the halftone background in the display image, the vertical crosstalk in a broad sense hardly occurs. The crosstalk hardly occurs. Further, the same applies to the display image based on the image signal regardless of the inversion driving method or the AC driving method in which the display image is displayed in relation to the black image as the solid image. There is almost no vertical crosstalk.

  Further, by unifying the polarity of the solid signal to the other one where the vertical crosstalk in the broad sense is likely to occur, a situation in which the vertical crosstalk in the broad sense is likely to occur occurs in the present invention for the solid image. However, in this case, as long as the potential of one data line is stable as a solid signal for a certain period (for example, a frame period) according to the solid image display method, the leakage current through the TFT that is likely to leak is -Since there is no potential difference between the drains, there is almost no flow and broad vertical crosstalk hardly occurs. Therefore, of course, narrow vertical crosstalk hardly occurs. Furthermore, in this case, since the potential of one data line is not stable as a solid signal when displaying a solid image in accordance with the solid image display method, the vertical crosstalk in a broad sense has occurred to the extent that it cannot be ignored. However, if the solid image is a black image or a white image, the change in gradation is slight due to a slight voltage change (drop or rise) in the pixel electrode, and it is recognized as vertical crosstalk in a narrow sense. Almost disappear. In addition, in this case, since the potential of one data line is not stable as a solid signal when displaying a solid image in accordance with the solid image display method, a broad vertical crosstalk occurs to the extent that it cannot be ignored. Even if, for example, black dots or black blocks are not displayed in the halftone background in the display image, for example, a solid black image, for example, is displayed as a solid image in time division. There is hardly any narrow crosstalk in the display image.

  For example, when a black signal is supplied to each data line in any cycle in order to display a black image as a solid image, the display image is compared with a case where such a black signal is not supplied at all. Of these, particularly in the halftone area, the influence of the black signal appears somewhat depending on the leak of each TFT, and the gradation may change slightly, but this is almost the entire image display area in the black image display cycle. Since this occurs uniformly, it does not cause the narrow vertical crosstalk as described above.

  As a result, according to the drive circuit of the present invention, it is possible to reduce the vertical crosstalk in the display image displayed on the electro-optical device while alternately displaying the solid image and the display image in some form. . For this reason, high-quality image display can be performed.

  In one aspect of the drive circuit of the electro-optical device according to the aspect of the invention, the image signal supply circuit supplies a black signal for displaying a black image as the solid image as the solid signal.

  According to this aspect, the black signal as the solid signal is supplied from the image signal supply circuit in a unified manner with a polarity that is more likely to cause vertical crosstalk in a broad sense between positive polarity and negative polarity with respect to the reference potential. . Therefore, the potential of one data line is not stable as a black signal when displaying a black image according to the display method of the black image, so even if the vertical crosstalk in a broad sense cannot be ignored, Since it is a black image, the change in gradation is slight due to a slight voltage change (drop or rise) in the pixel electrode, and is hardly recognized as a vertical crosstalk in a narrow sense. In addition, in this case, for example, a black dot or black block is not displayed in the halftone background in the display image, but a solid black image, for example, is basically displayed in a time division manner. There is almost no narrow crosstalk in the image.

  In another aspect of the drive circuit of the electro-optical device according to the aspect of the invention, the thin film transistor is an N-channel type, and the image signal supply unit supplies the positive image signal and the black image as the solid image. A negative black signal for display is supplied as the solid signal.

  According to this aspect, when an N-channel TFT is used as the pixel switching element, a vertical cross is applied to each pixel unit corresponding to each data line during a period in which an image signal is supplied to the pixel unit via the pixel switching element. In addition to suppressing the occurrence of talk, it is possible to make it easy to generate vertical crosstalk for each pixel portion corresponding to each data line during a period in which a black signal is supplied to the pixel portion via the pixel switching element. It becomes. Further, if an N-channel TFT is used for pixel switching, high-speed switching operation is possible.

  In another aspect of the driving circuit of the electro-optical device according to the aspect of the invention, the image signal supply circuit may supply one of the two scanning signals continuously supplied to the plurality of scanning lines. In addition, a period in which the image signal is supplied via the data line to the pixel portion corresponding to the scanning line to which the one scanning signal is supplied, and the other scanning signal is supplied from the two scanning signals. In addition, the solid signal is supplied via the data line to the pixel portion corresponding to the scanning line to which the other scanning signal is supplied.

  According to this aspect, the image signal supply circuit alternately supplies a solid signal and an image signal to each pixel unit in a cycle in which the scanning signal is supplied to one scanning line as a predetermined cycle. The “one scanning line” here generally corresponds to the first scanning line to which the first scanning signal of the partial area is supplied in each partial area.

  Then, as will be described later, by scanning each of a plurality of partial areas obtained by dividing the image display area, the display image and the solid image are displayed for each partial area of the image display area. It is possible to display the areas so that they are interchanged with each other.

  In the aspect in which the image signal is supplied during the period in which one of the scanning signals is supplied and the solid signal is supplied in the period in which the other scanning signal is supplied, the scanning line driving circuit may , For a plurality of partial areas obtained by dividing by a dividing line along the scanning line, the scanning signal is alternately supplied to the plurality of partial areas and in turn with respect to the plurality of scanning lines in each partial area. And the image signal supply circuit supplies the scanning signal after the scanning signal is supplied to one scanning line in each of the partial areas of the plurality of partial areas. Until the scanning signal is supplied to the line again, one of the image signal and the solid signal is supplied to the pixel portion in one of the two partial regions via the data line, and the two parts Territory Of the pixel portion in the other, the other may be configured to supply through the data lines of the image signal and the solid signal.

  When configured in this manner, when the electro-optical device is driven, the pixel portion in each partial area is scanned as described below for a plurality of partial areas obtained by dividing the image display area. At this time, each of the plurality of partial areas is a display area in which each pixel portion is driven based on an image signal, and each pixel portion is driven based on, for example, a black signal as a solid signal, and a black image is displayed as a solid image. Each pixel unit is driven with a pair of two partial areas that are either a black image display area and a display area and a black image display area.

  The above-described area scanning will be specifically described below. For two partial areas forming a pair, after a scanning signal is supplied to one scanning line in each partial area, the scanning signal of one partial area is supplied until the scanning signal is supplied again to the one scanning line. Within a period during which a scanning signal is supplied to each scanning line (this period may be referred to as a “scanning signal supply period” hereinafter), either one of the image signal and the solid signal is supplied from the image signal supply circuit. Supplied to the data line. In each pixel portion, either one of the image signal and the solid signal is supplied to the display element from the corresponding data line through the pixel switching element during the scanning signal supply period of the corresponding scanning line. The display element performs image display based on either the image signal or the solid signal.

  On the other hand, after the scanning signal is supplied to one scanning line in each partial region, the scanning signal is supplied to each scanning line in the other partial region until the scanning signal is supplied again to the one scanning line. Within the period, the other of the image signal and the solid signal is output from the image signal supply circuit and supplied to the plurality of data lines. In each pixel portion, either the image signal or the solid signal is supplied to the display element from the corresponding data line via the pixel switching element during the scanning signal supply period of the corresponding scanning line. The display element performs image display based on either the image signal or the solid signal.

  Here, the scanning signal is alternately supplied from the scanning line driving circuit to each partial area, and in each partial area, for example, each scan from the top to the bottom of the partial area along the arrangement direction of the scanning lines. Scan signals are sequentially supplied to the lines. Therefore, when the electro-optical device is driven, the pixel portion corresponding to one scanning line in one partial region is performed based on one of the written image signal and solid signal for two partial regions to be paired. Relative to or after image display, in the other partial area, the pixel portion corresponding to one scanning line performs image display based on one of the written image signal and solid signal.

  In addition, for the two partial areas to be paired, in each partial area, either one of two scanning signal supply periods continuous in each scanning line is supplied to the corresponding pixel portion, and either the image signal or the solid signal is supplied. In the other of the two consecutive scanning signal supply periods, either the image signal or the solid signal is supplied to the corresponding pixel portion. Accordingly, the two partial areas to be paired are based on the partial area in which the pixel unit is driven based on the image signal and the solid signal in a cycle in which the scanning signal is supplied to one scanning line in each partial area. The partial areas where the pixel portions are driven are alternately switched.

  Therefore, according to this aspect, for example, when a moving image is displayed in the image display area, when the obtained display image is observed with human eyes, the image display is performed in one partial area, and then in the other partial area. By displaying a black image as a solid image, it appears as if the display screen has been reset. Therefore, in this aspect, it is possible to reduce the afterimage feeling in the display image.

  In addition, when the image display is performed in one partial area while displaying the black as the specific color in the other partial area as described above without changing the field frequency of the image signal supplied to the data line, Compared with the case where image display is performed at the field frequency, the field frequency for the image signal supplied to each pixel unit is about half. That is, half of the field image is lost due to black display. For this reason, an adjustment that increases the field frequency, for example, an adjustment that supplies the image signal to the image signal supply means via the buffer at twice the field frequency may be performed. That is, for example, “double speed driving” may be performed. When the double speed driving is performed in this manner, the frequency of the polarity inversion of the output signal of the image signal supply circuit changes according to the number of the plurality of partial areas, and the occurrence of flicker due to the polarity inversion is suppressed as being hardly visible. It becomes possible. Therefore, in this aspect described above, higher quality image display can be performed.

  In this aspect in which each partial region is scanned, the plurality of partial regions are two partial regions obtained by being divided by the dividing lines so that the areas viewed in plan are substantially equal to each other. The scanning line driving circuit supplies the scanning signal to the plurality of scanning lines in each partial region alternately and to the two partial regions, and supplies the scanning signal in the one partial region. The one scanning line in the other partial area may be configured to be located halfway ahead of the image display area along the data line with respect to the scanning line.

  When configured in this manner, image display is performed based on an image signal in which a pixel portion corresponding to one scanning line in one of the two partial areas obtained by dividing the image display area into two equal parts is written. Prior to or after, for example, a black image is displayed as a specific color based on a solid signal in which a pixel portion corresponding to one scanning line in the other partial region is written. Therefore, for example, when displaying a moving image in the image display area, the afterimage feeling in the obtained display image can be more effectively reduced, and the high-quality image with reduced flicker can be uniformly distributed over the entire display image. An image can be displayed.

  In another aspect of the driving circuit of the electro-optical device according to the aspect of the invention, the image signal supply circuit supplies the image signal to all of the plurality of image portions and supplies the solid signal to all of the plurality of image portions. And are repeated alternately.

  In this aspect, when the electro-optical device is driven, the pixel unit corresponding to each scanning line is horizontally scanned, so that the display image is displayed in the image display area or after the display image is displayed. For example, a black image is displayed as a solid image in the image display area by horizontally scanning the pixel portion corresponding to each scanning line. Therefore, the display image and the black image are alternately displayed in the image display area for each screen. In this case, as in the above-described area scanning, half of the field image is lost due to black display, so “double speed driving” may be performed. If the double-speed driving is performed in this way, an image signal is supplied to each pixel unit in place of the black signal, so that the display image is displayed at the original frame frequency particularly in the case of a moving image. The smoothness of the same level can be obtained.

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

  According to the electro-optical device of the present invention, high-quality image display can be performed by driving the electro-optical device with the drive circuit of the present invention as described above.

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

  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. In addition, 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 (Degital Light Processing) and the like can also be realized.

In order to solve the above-described problem, the electro-optical device driving method of the present invention electrically connects a plurality of data lines and a plurality of scanning lines, a display element, and the data lines and the scanning lines in an image display region on the substrate. And a plurality of pixel units each including a single-channel thin film transistor that controls switching of the display element, wherein a scanning signal is applied to each of the plurality of scanning lines. a first step of supplying a, (i) of the positive polarity and negative polarity with respect to the reference potential, the thin film transistor has the positive polarity when Ru N-channel type der, the thin film transistor is a P-channel type having said negative polarity when a particular color in the image display area and having an image signal and (ii) the image signal is different from the polarity for displaying a display image on the image display area And a second step of supplying a solid signal for displaying the solid image alternately to the plurality of pixel portions through the data line at a predetermined cycle.

  According to the driving method of the present invention, as in the driving circuit of the present invention described above, vertical crosstalk in a display image displayed on the electro-optical device is reduced while alternately displaying a solid image and a display image in some form. It becomes possible to do. For this reason, high-quality image display can be performed.

  In an aspect of the driving method of the electro-optical device of the present invention, in the second step, a black signal for displaying a black image as the solid image is supplied as the solid signal.

  According to this aspect, the potential of one data line is not stable as a black signal when displaying a black image according to the display method of the black image. Even if it is a black image, the change in gradation is slight due to a slight voltage change (drop or rise) in the pixel electrode, and is hardly recognized as a vertical crosstalk in a narrow sense. In addition, in this case, for example, a black dot or black block is not displayed in the halftone background in the display image, but a solid black image, for example, is basically displayed in a time division manner. There is almost no narrow crosstalk in the image.

  In another aspect of the driving method of the electro-optical device according to the aspect of the invention, the thin film transistor is an N-channel type, and supplies the positive image signal and displays a black image as the solid image in the second step. Therefore, a negative black signal is supplied as the solid signal.

  According to this aspect, when an N-channel TFT is used as the pixel switching element, a vertical cross is applied to each pixel unit corresponding to each data line during a period in which an image signal is supplied to the pixel unit via the pixel switching element. In addition to suppressing the occurrence of talk, it is possible to make it easy to generate vertical crosstalk for each pixel portion corresponding to each data line during a period in which a black signal is supplied to the pixel portion via the pixel switching element. It becomes. Further, if an N-channel TFT is used for pixel switching, high-speed switching operation is possible.

  In another aspect of the driving method of the electro-optical device according to the aspect of the invention, in the second step, in a period in which one of the two scanning signals continuously supplied to the plurality of scanning lines is supplied. The image signal is supplied to the pixel portion corresponding to the scanning line to which the one scanning signal is supplied through the data line, and the other scanning signal is supplied from the two scanning signals. The solid signal is supplied via the data line to the pixel portion corresponding to the scanning line to which the other scanning signal is supplied.

  According to this aspect, the plurality of partial areas obtained by dividing the image display area are respectively scanned, thereby displaying the display image and the solid image for each partial area of the image display area. It is possible to display the areas so that they are interchanged with each other.

  In the aspect in which the image signal is supplied during the period in which one scanning signal is supplied and the solid signal is supplied in the period in which the other scanning signal is supplied, in the first step, the image display area is For a plurality of partial areas obtained by dividing by the dividing lines along the scanning lines, the scanning signals are supplied alternately to the plurality of partial areas and sequentially to the plurality of scanning lines in each partial area. In the second step, after the scanning signal is supplied to one scanning line in each of the partial regions of the plurality of partial regions, a pair of the partial regions is supplied to the one scanning line. Until the scanning signal is supplied again, one of the image signal and the solid signal is supplied to the pixel portion in one of the two partial regions via the data line, and the two partial regions are supplied. The pixel portion in the other, while the may be driven to supply via the data lines of the image signal and the solid signal.

  By driving in this way, it is possible to reduce the afterimage feeling in the display image. In addition, for example, by driving at double speed, the frequency of the polarity inversion of the output signal of the image signal supply circuit changes according to the number of the plurality of partial areas, and the occurrence of flicker due to the polarity inversion is suppressed as being difficult to see. It becomes possible to do. Therefore, in this aspect described above, higher quality image display can be performed.

  In this aspect in which each partial region is scanned, the plurality of partial regions are obtained by dividing the plurality of partial regions so that the areas viewed in plan are substantially equal to each other by the dividing lines in the first step. The scanning signal is supplied to two partial areas alternately and line-sequentially to the plurality of scanning lines in each partial area, and the other part is applied to the one scanning line in the one partial area. The one scanning line in the region is located halfway ahead of the image display region along the data line.

  In this aspect, for example, when a moving image is displayed in the image display area, the afterimage feeling in the obtained display image can be more effectively reduced, and the flicker can be reduced uniformly over the entire display image. A quality image can be displayed.

  In another aspect of the driving method of the electro-optical device of the invention, in the second step, the image signal is supplied to all of the plurality of image portions, and the solid signal is supplied to all of the plurality of image portions. Are repeated alternately.

  In this aspect, in the image display area, a display image and, for example, a black image as a solid image are alternately displayed for each screen. In this case, if double-speed driving is performed, an image signal is supplied to each pixel unit in place of the black signal, so that the image is displayed at the original frame frequency especially in the case of a moving image. The smoothness of the same level can be obtained.

  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, the electro-optical device of the invention is applied to a liquid crystal device.

<1: First Embodiment>
First, a first embodiment according to the electro-optical device of the invention will be described with reference to FIGS.

<1-1: Overall configuration of electro-optical device>
An overall configuration of a liquid crystal panel as an example of an electro-optical panel in a liquid crystal device as an example of the electro-optical device of the present invention will be described with reference to FIGS. Here, FIG. 1 is a schematic plan view of a liquid crystal panel when the TFT array substrate is viewed from the side of the counter substrate together with each component formed thereon, and FIG. 2 is a schematic diagram of HH ′ of FIG. It is sectional drawing. Here, a TFT active matrix driving type liquid crystal device with a built-in driving circuit is taken as an example.

  1 and 2, in the liquid crystal panel 100 according to the present embodiment, the TFT array substrate 10 and the 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.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. Further, in the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (inter-substrate gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  Of the peripheral regions located around the image display region 10 a, the data line driving circuit 101 and the external circuit connection terminal 102 are arranged on one side of the TFT array substrate 10 in the region located outside the seal region where the sealing material 52 is disposed. It is provided along. The scanning line driving circuit 104 is provided along one of the two sides adjacent to the one side so as to be covered with the frame light shielding film 53. The scanning line driving circuit 104 may be provided along two sides adjacent to one side of the TFT array substrate 10 provided with the data line driving circuit 101 and the external circuit connection terminal 102. In this case, the two scanning line driving circuits 104 are connected to each other by a plurality of wirings provided along the remaining one side of the TFT array substrate 10.

  In addition, vertical conduction members 106 that function as vertical conduction terminals between the two substrates are disposed at the four corners of the counter substrate 20. On the other hand, the TFT array substrate 10 is provided with vertical conduction terminals in a region facing these corner portions. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

  In FIG. 2, on the TFT array substrate 10, an alignment film is formed on the pixel electrode 9a after the pixel switching TFT, the scanning line, the data line and the like are formed. On the other hand, on the counter substrate 20, in addition to the counter electrode 21, a lattice-shaped or striped light-shielding film 23 and an alignment film are formed on the uppermost layer portion. The liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films.

  Although not shown in FIGS. 1 and 2, on the TFT array substrate 10, in addition to the data line driving circuit 101, the scanning line driving circuit 104, etc., precharge signals having a predetermined voltage level are applied to a plurality of data lines. A precharge circuit to be supplied in advance of each image signal, an inspection circuit for inspecting the quality, defects, etc. of the electro-optical device during manufacture or at the time of shipment may be formed.

<1-2: Overall configuration of electro-optical device>
The overall configuration of the liquid crystal device will be described with reference to FIGS. FIG. 3 is a block diagram showing the overall configuration of the liquid crystal device, and FIG. 4 is a block diagram showing the electrical configuration of the liquid crystal panel.

  As shown in FIG. 3, the liquid crystal device includes a liquid crystal panel 100, an image signal supply circuit 300, a first frame memory 62 and a second frame memory 63, a timing control circuit 400, and a power supply circuit 700 as main parts.

  The timing control circuit 400 is configured to output various timing signals used in each unit. A timing signal output means that is a part of the timing control circuit 400 generates a dot clock that is a minimum unit clock and scans each pixel. Based on this dot clock, a Y clock signal CLY and an inverted Y clock signal are generated. CLYinv, X clock signal CLX, inverted X clock signal XCLinv, Y start pulse DY and X start pulse DX are generated. Further, in the timing control circuit 400, two types of enable signals ENB1 and ENB2 that determine the output timing of a scanning signal described later are generated.

  In this embodiment, the main part of the broader “image signal supply circuit” according to the present invention includes a data line in addition to the image signal supply circuit 300 and the first and second frame memories 62 and 63 shown in FIG. A drive circuit 101 is included. Input image data DATA is input to the image signal supply circuit 300 from the outside. The image signal supply circuit 300 generates two types of field data based on the input image data DATA, and generates the two types generated in a cycle in which the scanning signal is supplied to one scanning line as will be described later. Is temporarily stored in one of the first frame memory 62 and the second frame memory 63, and one type of stored field data is read from the other. The two types of field data include data for displaying one display image and data for displaying one black image.

  Then, the image signal supply circuit 300 performs a predetermined process on the read one type of field data. As an example of this predetermined processing, the image signal supply circuit 300 performs serial-parallel conversion of, for example, one type of field data to generate N-phase, for example, six-phase (N = 6) image signals VID1 to VID6. There is. Further, the image signal supply circuit 300 inverts the voltage of the generated image signal VIDk (where k = 1, 2, 3,..., 6) to positive polarity and negative polarity with respect to a predetermined reference potential v0. After that, the image signal VIDk is output. As will be described later, the image signal VIDk here has a first display potential v1 (+) for displaying a display image as a narrowly-defined “image signal” according to the present invention, and the present invention. The “black signal” includes both of those having the second display potential vb (−) for displaying a black image.

  The power supply circuit 700 supplies a common power supply having a predetermined common potential LCC to the counter electrode 21 shown in FIG. In the present embodiment, the counter electrode 21 is formed on the lower side of the counter substrate 20 shown in FIG. 2 so as to face the plurality of pixel electrodes 9a.

  Next, an electrical configuration of the liquid crystal panel 100 will be described.

  As shown in FIG. 2, the liquid crystal panel 100 is provided with an internal drive circuit including a scanning line drive circuit 104 and a data line drive circuit 101 in the peripheral region of the TFT array substrate 10.

  Although specifically described later, the scanning line driving circuit 104 can perform basic line-sequential horizontal scanning by supplying a Y clock signal CLY, an inverted Y clock signal CLYinv, and a Y start pulse DY. ing. Further, the scanning line driving circuit 104 outputs the scanning signals G1, G2,..., Gm in the order described later at a timing based on the supplied enable signals ENB1 and ENB2.

  In the present embodiment, the main part of the data line driving circuit 101 includes a sampling signal supply circuit 101a and a sampling circuit 101b. The sampling signal supply circuit 101a is supplied with the X clock signal CLX, the inverted X clock signal CLXinv, and the X start pulse DX. When the X start pulse DX is input, the sampling signal supply circuit 101a sequentially generates and outputs sampling signals S1,..., Sn at a timing based on the X clock signal CLX and the inverted X clock signal XCLXinv.

  The sampling circuit 101b includes a plurality of sampling switches 202 each composed of a P-channel or N-channel single-channel TFT or a complementary TFT.

  The liquid crystal panel 100 further includes data lines 114 and scanning lines 112 wired vertically and horizontally in the image display area 10a occupying the center of the TFT array substrate, and the pixel portions 70 corresponding to the intersections are arranged in a matrix. A single-channel TFT 116 is provided as a pixel switching element for controlling the switching of the pixel electrode 9a and the pixel electrode 9a of the liquid crystal element 118 arranged. In this embodiment, the total number of scanning lines 112 is assumed to be m (where m is a natural number of 2 or more), and the total number of data lines 114 is assumed to be n (where n is a natural number of 2 or more). To do. The TFT 116 is configured using an N-channel transistor.

  As described above, for example, the image signals VID <b> 1 to VID <b> 6 that are serially / parallel-developed in six phases are supplied to the liquid crystal panel 100 via the image signal lines 171.

  In the sampling circuit 101b, N, in this embodiment, six sampling switches 202 are grouped, and sampling signals Si (i = 1, 2,..., N) are respectively supplied to the sampling switches 202 belonging to the group. Is entered. The sampling switch 202 belonging to one group includes N data lines, in this embodiment, six data lines 114 as one group, and samples the image signal VIDk with respect to the data lines 114 belonging to the first group according to the sampling signal Si. Supply. That is, the data line 114 belonging to the first group and the image signal line 171 are electrically connected via the sampling switch 202 belonging to the first group. Therefore, in this embodiment, since the n data lines 114 are driven for each data line 114 belonging to one group, the driving frequency can be suppressed.

  In FIG. 4, focusing on the configuration of one pixel portion 70, the data line 114 to which the image signal VIDk is supplied is electrically connected to the source electrode of the TFT 116, while the gate electrode of the TFT 116 is The scanning line 112 to which the scanning signal Gj (where j = 1, 2, 3,..., M) is supplied is electrically connected, and the drain electrode of the TFT 116 is connected to the pixel electrode 9a of the liquid crystal element 118. Is connected. Here, in each pixel portion 70, the liquid crystal element 118 has a liquid crystal sandwiched between the pixel electrode 9 a and the counter electrode 21. Accordingly, each pixel unit 70 is arranged in a matrix corresponding to each intersection of the scanning line 112 and the data line 114.

  An image signal VIDk is supplied to the pixel electrode 9a of the liquid crystal element 118 from the data line 114 at a predetermined timing by closing the switch of the TFT 116 for a certain period. As a result, an applied voltage defined by the potentials of the pixel electrode 9 a and the counter electrode 21 is applied to the liquid crystal element 118. The liquid crystal modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel, and in the normally black mode, the light is incident according to the voltage applied in units of each pixel. The light transmittance is increased, and light having a contrast corresponding to the image signal VIDk is emitted from the liquid crystal panel 100 as a whole.

  Here, a storage capacitor 119 is added in parallel with the liquid crystal element 118 in order to prevent the held image signal from leaking. For example, since the voltage of the pixel electrode 118 is held by the storage capacitor 119 for a time that is three orders of magnitude longer than the time when the source voltage is applied, the holding characteristics are improved, resulting in a high contrast ratio. Become.

<1-3: Operation of electro-optical device>
Next, the operation of the liquid crystal device will be described with reference to FIGS. 5 to 11 in addition to FIGS.

  First, a detailed configuration of the scanning line driving circuit 104 shown in FIG. 1 or 4 will be described with reference to FIG. FIG. 5 shows an example of the configuration of the scanning line driving circuit 104.

  Here, in the following, for the sake of simplicity, the total number of scanning lines 112 is set to m = 4, and the image display area 10a is divided into two equal parts by dividing lines 600 along the scanning lines 112 as shown in FIG. A case where region scanning is performed on the obtained first partial region 10aa and second partial region 10ab will be described.

  In FIG. 5, the main part of the scanning line driving circuit 104 corresponds to a Y-side shift register 104a to which a Y clock signal CLY, an inverted Y clock signal CLYinv, and a Y start pulse DY are input, and four scanning lines 112. And an output control unit 104b composed of four logic circuits. One logic circuit includes, for example, a NAND circuit 67 and a NOT circuit 68, and one output signal from the Y-side shift register 66 and one of two types of enable signals ENB1 or ENB2 are input to the NAND circuit 67. The The output signals of the NAND circuits 67 are output as scanning signals G1, G2, G3, and G4 to the corresponding scanning lines 112 via the NOT circuit 68.

  Next, region scanning performed on the first partial region 10aa and the second partial region 10ab will be described in detail with reference to FIGS. 6 to 10 in addition to FIGS. FIG. 6 is an explanatory diagram for explaining the generation of the image signal VIDk in the image signal supply circuit 300, FIG. 7 is a timing chart for explaining the operation of the scanning line driving circuit 104, and FIG. 4 is a timing chart showing changes with time of various signals for driving each data line 114 and each scanning line 112; Further, FIG. 9 is a diagram showing the characteristics of the TFT 116 as the pixel switching element, with the horizontal axis representing the gate-source voltage (Vgs) and the vertical axis representing the source-drain current (Isd). FIG. 10A and FIG. 10B are explanatory diagrams for conceptually explaining the area scanning in the present embodiment.

  In FIG. 6, the image signal supply circuit 300 supplies the first signal after the scanning signal Gj is supplied to the first scanning line 112 in each of the first and second partial regions 10aa and 10ab described later. Until the scanning signal Gj is again supplied to the scanning line 112 (hereinafter, this period may be referred to as one vertical scanning period in the present embodiment), each pixel unit 70 in the first partial region 10aa performs the first operation. Image display for displaying a display image in the first partial area 10aa is performed, and black display for displaying a black image in the second partial area 10ab is performed in each pixel unit 70 in the second partial area 10ab. In addition, the voltage of the image signal VIDk is adjusted. Further, the image signal supply circuit 300 has a cycle in which the first partial region 10aa and the second partial region 10ab are supplied with the scanning signal Gj to the first scanning line 112 described above, that is, one vertical scanning period ( The image signal VIDk is generated so as to be alternately switched based on the image signal VIDk every one frame period).

  For example, as shown in FIG. 6, the image signal supply circuit 300 generates the image signal VIDk for each ½ field based on one type of field data. The image signal VIDk is inverted in polarity with respect to a predetermined reference potential v0 for each scanning signal supply period (that is, for each horizontal scanning period), and the first display potential v1 (+) In other words, the voltage is adjusted to a voltage defined by the second display potential vb (−) and the reference potential v0. In the present embodiment, the display voltage defined by the first display potential v1 (+) and the reference potential v0 is generated as a positive voltage, and is defined by the second display potential vb (−) and the reference potential v0. The black display voltage is generated as a negative voltage. In one vertical scanning period, the image signal VIDk of the display voltage and the image signal VIDk of the black display voltage are alternately output from the image signal supply circuit 300 every scanning signal supply period.

  The 1/2 field period has a length equivalent to one vertical scanning period (one frame period). In FIG. 6, of two vertical scanning periods adjacent to each other on the time axis, in one vertical scanning period, one scanning signal supply period in which the image signal VIDk is adjusted to the display voltage is displayed in black. The image signal VIDk is generated so as to come first relative to the other scanning signal supply period adjusted to the voltage. On the other hand, in the other vertical scanning period, one scanning signal supply period in which the image signal VIDk is adjusted to the display voltage is compared to another scanning signal supply period in which the image signal VIDk is adjusted to the black display voltage. The image signal VIDk is generated so as to come relatively later.

  Next, region scanning in one vertical scanning period will be described with reference to FIGS.

  In one vertical scanning period, scanning signals G1, G2, G3, and G4 are alternately supplied to the first partial region 10aa and the second partial region 10ab from the scanning line driving circuit 104 shown in FIG. In each of the partial region 10aa and the second partial region 10ab, the scanning signals G1 and G2 or G3 and G4 are applied to each scanning line 112 from the top to the bottom of the partial region 10aa or 10ab along the arrangement direction of the scanning lines 112, respectively. Sequentially supplied.

  As shown in FIG. 7, the start pulses SR1 to SR4 from the Y-side shift register 66 are the same for the respective scanning lines 112 so that the first partial region 10aa and the second partial region 10ab are simultaneously scanned horizontally. Output at timing. In other words, in the first partial region 10aa and the second partial region 10ab, the start pulses SR1 and SR3 corresponding to the scanning line 112 to which the scanning signal Gj is supplied first and the scanning signal Gj are supplied second. The start pulses SR2 and SR4 corresponding to the scanning line 112 are alternately output every two horizontal scanning periods. On the other hand, the enable signals ENB1 and ENB2 alternately rise from the low level to the high level every horizontal scanning period. Therefore, among the start pulses SR1 to SR4, one of the enable signals ENB1 and ENB2 output at the rising timing is selected by the logic circuit and output to the scanning line 112 as the scanning signal Gj. As a result, the scanning signals G1 to G4 are sequentially output from the scanning line driving circuit 104 as shown in FIG.

  In FIG. 8, when one vertical scanning period is started at time t0, in the first partial region 10aa, the scanning line 112 corresponding to the first scanning signal G1 of the first partial region 10aa from the scanning line driving circuit 104 corresponds. And the scanning signal supply period of the first scanning line 112 is started. Note that the period from time t0 to time t3 when the first scanning signal G1 is at the high level is the scanning signal supply period of the first scanning line 112.

  The image signal VIDk adjusted to the display voltage is supplied from the image signal supply circuit 300 during the image signal supply period from the time t1 to the time t2 within the scan signal supply period of the first scan line 112. Further, during the image signal supply period, sampling signals S1, S2,..., Sn as shift register outputs are sequentially supplied from the sampling signal supply circuit 101a, and the sampling circuit 101b sequentially turns on each sampling switch 202 belonging to a group. It becomes. At this time, if serial-parallel development is employed, the sampling switches 202 belonging to the first group are collectively turned on. Particularly in the present embodiment, in one continuous image signal supply period (for example, the period from time t1 to t2 in FIG. 8), the sampling signals S1,..., Corresponding to the image signal VIDk for one line. Sn is output. Further, in another continuous image signal supply period (for example, the period from time t4 to t5 in FIG. 8), the sampling signal S1,..., Corresponding to the image signal VIDk for another line. Sn is output. In any case, the image signal VIDk is sampled only during the image signal supply period, and the image signal VIDk is supplied to the data line 114.

  The display voltage image signal VIDk is supplied to the data line 114 through the sampling switch 202 in the on state, and is supplied to the pixel unit 70 corresponding to the first scanning line 112 through the data line 114. . Thus, the image signal VIDk for displaying the display image is written in the pixel portion 70 corresponding to the first scanning line 112 during the period from the time t1 to the time t2.

  Thereafter, when the scanning signal supply period of the first scanning line 112 ends at time t3, the first partial line (scanning line driving circuit) of the second partial area 10ab is received from the scanning line driving circuit 104 in the second partial area 10ab. According to the output order from 104, the second scanning signal G3 is supplied to the corresponding scanning line 112, and the scanning signal supply period of the second scanning line 112 is started.

  Within the scanning signal supply period of the second scanning line 112, the image signal VIDk of the black display voltage is the image signal in the image signal supply period from time t4 to time t5, that is, in a narrow sense, “black signal supply period”. Supplied from circuit 300. The image signal VIDk is sequentially turned on for each sampling switch 202 belonging to one group in accordance with the sampling signals S1, S2,..., Sn supplied from the sampling signal supply circuit 101a. Are supplied to each data line 114. Further, the image signal VIDk is supplied to the pixel unit 70 corresponding to the second scanning line 112 via each data line 114. Thus, the image signal VIDk for displaying the black image is written in the pixel portion 70 corresponding to the second scanning line 112 during the period from the time t4 to the time t5.

  Thereafter, when the scanning signal supply period of the second scanning line 112 is completed at time t6, the second partial scanning line (scanning line driving circuit) of the first partial area 10aa is received from the scanning line driving circuit 104 in the first partial area 10aa. According to the output order from 104, the third scanning signal G2 is supplied to the corresponding scanning line 112, and the scanning signal supply period of the third scanning line 112 is started.

  In the scanning signal supply period of the third scanning line 112, in the image signal supply period from time t7 to time 8, the third scanning line is the same as the pixel unit 70 corresponding to the first scanning line 112. An image signal VIDk for displaying a display image is written in the pixel unit 70 corresponding to 112.

  Subsequently, when the scanning signal supply period of the third scanning line 112 is completed at time t9, the second partial region 10ab is scanned by the second (scanning line drive) of the second partial region 10ab in the second partial region 10ab. According to the output order from the circuit 104, the fourth scanning signal G4 is supplied to the corresponding scanning line 112, and the scanning signal supply period of the fourth scanning line 112 is started.

  In the scanning signal supply period of the fourth scanning line 112, in the image signal supply period from time t10 to time 11, similarly to the pixel unit 70 corresponding to the second scanning line 112, the fourth scanning line. An image signal VIDk for displaying a black image is written in the pixel unit 70 corresponding to 112.

  Thereafter, one vertical scanning period ends at time t12. As described above, in one vertical period, a black image is displayed during the scanning signal supply period on the pixel portion 70 corresponding to the second and fourth scanning lines 112, that is, the scanning lines 112 of the second partial region 10ab. An image signal VIDk for writing is written. At this time, when the image signal VIDk is supplied to each data line 114, the voltage between the gate and the source of the TFT 116 in the pixel portion 70 corresponding to each data line 114 is a negative black display voltage (Vb1 in FIG. 9). It is shown as). As a result, according to the characteristics of the N-channel TFT 116 shown in FIG. 9, the gate-source voltage (Vgs) becomes a value close to the threshold voltage of the TFT 116, and the characteristics of the TFT 116 are likely to fluctuate. Therefore, in the scanning signal supply period of each scanning line 112 in the second partial region 10ab, in the pixel portion 70 corresponding to each data line 114, an off current such as a light leakage current is generated in the TFT 116, thereby causing vertical crosstalk. It will be in a state where it is likely to occur. However, even if vertical crosstalk occurs, it is possible to make it difficult for the image displayed in the image display area 10a to be visually recognized.

  On the other hand, an image signal VIDk for displaying a display image is written in the pixel portion 70 corresponding to the first and third scanning lines 112, that is, each scanning line 112 of the first partial region 10aa. It is. The image signal VIDk has a positive display voltage different from the polarity of the black display voltage. Therefore, it is possible to suppress off-current such as light leakage current in the pixel unit 70 corresponding to each data line 114 during the scanning signal supply period of each scanning line 112 in the first partial region 10aa. Therefore, it is possible to suppress the occurrence of vertical crosstalk during the scanning signal supply period of each scanning line 112 in the first partial region 10aa. Therefore, in the present embodiment, it is possible to reduce vertical crosstalk in the display image displayed in the image display area 10a.

  Further, according to the area scanning described with reference to FIG. 8, as shown in FIG. 10A, the display image is displayed by the pixel unit 70 corresponding to the scanning line 112 of the first partial area 10aa. After the image display is performed, a black image is displayed by the pixel unit 70 corresponding to one scanning line 112 of the second partial region 10ab, which is located halfway ahead of the image display region 10a with respect to the one scanning line 112. An image is displayed for the purpose. In each of the first partial region 10aa and the second partial region 10ab, the pixel unit 70 corresponding to each scanning line 112 is driven line-sequentially from the top to the bottom of the partial region 10aa or 10ab.

  When one vertical scanning period ends at time t12, the image signal VIDk is adjusted to the display voltage and the black display voltage in the subsequent one vertical scanning period, as already described in the image signal supply circuit 300. The order is reversed from the one vertical scanning period described with reference to FIG. Accordingly, as shown in FIG. 10B, the first partial region 10aa and the second partial region 10ab are interchanged, and the pixel unit 70 corresponding to each scanning line 112 is located above the partial region 10aa or 10ab. Driven line-sequentially downward.

  Here, FIG. 11A schematically shows a display screen visually recognized when a moving image is displayed in the image display area 10a in the present embodiment, and FIG. 11B shows a comparative example. 3 schematically shows a display screen that is visually recognized when a moving image is displayed in the image display area 10a.

  In this embodiment, as shown in FIG. 11A, when an object 90 traveling in the direction of the arrow A is displayed in the image display area 10a, when the obtained display image is observed with human eyes, for example, After the image display is performed in the first partial area 10aa, the black image display is performed in the second partial area 10ab, so that the display screen appears to have been reset. Therefore, in the present embodiment, it is possible to perform image display in which an afterimage is hardly visually recognized in the image display region 10a.

  On the other hand, in the comparative example in which the same moving image as in FIG. 11A is displayed in the image display area 10a by the conventional driving described above without performing the area scanning according to the present embodiment, for example, in FIG. As shown, an afterimage B in which the object A moving in the direction of the arrow A has a tail is visually recognized.

  Thus, in this embodiment, it is possible to reduce the afterimage feeling in the display image displayed in the image display area 10a. One display image and one black image are displayed every one field period, that is, every two vertical scanning periods. That is, according to the present embodiment, the scanning line driving circuit 104 and the data line driving circuit 101 are driven at double speed. Therefore, the polarity inversion frequency of the image signal VIDk can be doubled as compared with the case where such double speed driving is not performed. Therefore, it is possible to suppress the occurrence of flicker accompanying the reversal of the polarity of the image signal VIDk as being hardly visible. As a result, according to the present embodiment as described above, high-quality image display can be performed on the liquid crystal panel 100.

  In the present embodiment, each of the plurality of partial areas obtained by dividing the image display area 10a by two or more division lines is either a display image display area or a black image display area. In addition, region scanning may be performed in a manner similar to the above-described procedure with a pair of two partial regions serving as a region for displaying a display image and a region for displaying a black image.

  In addition, the order of selecting scanning lines in each partial area, that is, the scanning order may be line sequential from the top as shown in FIG. 9, or may be a predetermined order different from this, for example, line sequential from the bottom or from the middle. Various scanning orders such as line sequential can be employed. In any case, as long as the scanning order is determined in advance, there is no particular problem if an image signal is supplied to the data line accordingly. However, in view of avoiding complication of signal processing in the image signal supply circuit (see FIG. 3) and avoiding complication of wiring related to the scan line (FIG. 5), the scanning order as shown in FIG. desirable.

<1-4;Modification>
In this embodiment, a P-channel TFT 116 may be used as the pixel switching element instead of the N-channel TFT 116. FIG. 12 shows the characteristics of the P-channel TFT 116 as in FIG. As shown in FIG. 12, according to the characteristics of the P-channel TFT 116, the characteristics of the TFT 116 are likely to change when the gate-source voltage changes from positive to negative. Therefore, in this case, as compared with the case where the N-channel TFT 116 is used, the voltage of the image signal VIDk may be adjusted in the image signal supply circuit 300 with the black display voltage having a positive polarity and the display voltage having a negative polarity. By doing so, it is possible to reduce the vertical crosstalk in the display image as in the above-described embodiment.

<2; Second Embodiment>
Next, a second embodiment according to the electro-optical device of the invention will be described. In the second embodiment, the liquid crystal device as the electro-optical device is different from the first embodiment in the operation of the image signal supply circuit and the configuration and operation of the scanning line driving circuit. Therefore, hereinafter, the configuration and operation of the liquid crystal device will be described with reference to FIGS. 13 and 14 only with respect to differences from the first embodiment. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and shown, and the overlapping description is abbreviate | omitted.

  In this embodiment, the main part of the scanning line driving circuit includes a shift register, unlike the scanning line driving circuit 104 shown in FIG. That is, when the Y start pulse DY is input, the scanning line driving circuit sequentially generates and outputs the scanning signals G1,..., Gm at a timing based on the Y clock signal CLY and the inverted Y clock signal CLYinv.

  Next, with reference to FIGS. 13 and 14, the operation of the liquid crystal device according to the second embodiment will be described assuming that the total number of scanning lines 112 is m = 4. FIG. 13 is a timing chart showing temporal changes of various signals related to the operation of the liquid crystal device according to the second embodiment. FIGS. 14A and 14B are conceptual views of horizontal scanning of each pixel unit. An explanatory diagram for explaining the system is shown. In the second embodiment, the configuration of the liquid crystal device and the main electrical configuration of the liquid crystal panel are the same as those of the first embodiment, and therefore, this configuration will be described with reference to FIGS. 3 and 4 in the following description. In the following description, the TFT 116 is configured using an N-channel transistor.

  In the second embodiment, as shown in FIG. 13, the image signal supply circuit 300 includes two vertical scanning periods that are adjacent to each other on the time axis, that is, one field period, in one vertical scanning period, that is, ½ field period. Generates an image signal VIDk so that one display image is displayed in the image display area 10a, and one black image is displayed in the image display area 10a in the other vertical scanning period, that is, a 1/2 field period. The image signal VIDk is generated. Therefore, the polarity of the voltage of the image signal VIDk is inverted every vertical scanning period, and the image signal VIDk is within the scanning signal supply period of each scanning line 112 in one of the two vertical scanning periods. The image signal VIDk is adjusted to a negative black display voltage within the scanning signal supply period of each scanning line 112 in the other vertical scanning period of the two vertical scanning periods.

  With reference to FIG. 13, the operation of the liquid crystal device in one field period, that is, two vertical scanning periods that are temporally continuous will be specifically described. In FIG. 13, when one vertical scanning period relatively positioned on the time axis of two vertical scanning periods is started at time t20, the first scanning signal G1 from the scanning line driving circuit corresponds. The scanning signal supply period of the first scanning line 112 is started. Note that a period from time t20 to time t23 when the first scanning signal G1 is at a high level is a scanning signal supply period of the first scanning line 112.

  In the image signal supply period from the time t21 to the time t22 within the scan signal supply period of the first scan line 112, an image is displayed on the pixel unit 70 corresponding to the first scan line 112 as the image signal VIDk. The image signal D1 adjusted to the display voltage for performing the above is supplied from the image signal supply circuit 300. In the image signal supply period, the sampling circuits 101b are sequentially turned on for each sampling switch 202 belonging to the group in accordance with the sampling signals S1, S2,..., Sn supplied from the sampling signal supply circuit 101a. The image signal D1 supplied from the image signal supply circuit 300 is supplied to the data line 114 via the sampling switch 202 in the on state, and the pixel unit 70 corresponding to the first scanning line 112 via the data line 114. To be supplied.

  After that, when the second scanning signal G2 is supplied from the scanning line driving circuit, the period from time t23 to time t26 becomes the scanning signal supply period of the second scanning line 112. In the image signal supply period from time t24 to time t25 within the second scanning signal supply period, a display for displaying an image on the pixel unit 70 corresponding to the second scanning line 112 as the image signal VIDk. An image signal D 2 adjusted to a voltage is supplied from the image signal supply circuit 300. Then, the image signal D <b> 2 is supplied to the pixel unit 70 corresponding to the second scanning line 112, similarly to the first scanning line 112.

  After that, when the third scanning signal G3 is supplied from the scanning line driving circuit, the period from time t26 to time t29 becomes the scanning signal supply period of the third scanning line 112. In the image signal supply period from time t27 to time t28 within the third scan signal supply period, an image display is performed on the pixel unit 70 corresponding to the third scan line 112 as the image signal VIDk. Similar to the first and second scanning lines 112, the image signal D3 adjusted to the display voltage is supplied to the pixel unit 70 corresponding to the third scanning line 112.

  In addition, since the fourth scanning signal G4 is supplied from the scanning line driving circuit, the period from time t29 to time t32 becomes the scanning signal supply period of the fourth scanning line 112. In the image signal supply period from the time t30 to the time t31 within the fourth scan signal supply period, an image display is performed in the pixel unit 70 corresponding to the fourth scan line 112 as the image signal VIDk. The image signal D4 adjusted to the display voltage is supplied to the pixel unit 70 corresponding to the fourth scanning line 112, similarly to the first to third scanning lines 112.

  Subsequently, at time t32, one vertical scanning period positioned relatively later on the time axis among the two vertical scanning periods is started. In this one vertical scanning period, that is, the period from time t32 to time t44, for example, as shown in FIG. 13, one black signal Db is continuously supplied from the image signal supply circuit 300 as the image signal VIDk. Further, in this one vertical scanning period, the image signal is applied to the pixel unit 70 corresponding to each of the first to fourth scanning lines 112 in the same manner as in the previous one vertical scanning period from time t20 to time t32. A black signal Db is written as VIDk.

  More specifically, within the scanning signal supply period of the first scanning line 112 from time t32 to time t35, the image signal supply period from time t33 to time t34, that is, “black signal supply period in a narrow sense” The black signal Db is supplied to the pixel unit 70 corresponding to the first scanning line 112. Similarly to the first scanning line 112, the pixel unit 70 corresponding to the second scanning line 112 is provided in the scanning signal supply period of the second scanning line 112 from time t <b> 35 to time t <b> 38. The black signal Db is supplied during the image signal supply period from time t36 to time t37, and the third scanning line 112 from time t38 to time t41 is supplied to the pixel unit 70 corresponding to the third scanning line 112. In the scanning signal supply period, the black signal Db is supplied in the image signal supply period from time t39 to time t40, and the pixel unit 70 corresponding to the fourth scanning line 112 is supplied from time t41 to time t44. In the scanning signal supply period of the fourth scanning line 112, the black signal Db is supplied during the image signal supply period from time t42 to time t43.

  According to the operation of the liquid crystal device described with reference to FIG. 13, as shown in FIGS. 14A and 14B, in the image display region 10 a, the pixel unit 70 corresponding to each scanning line 112 is The image display area 10a is driven line-sequentially from the top to the bottom. Then, as shown in FIG. 14A, in the ½ field period of one field period, each pixel unit 70 is horizontally scanned as described above, whereby a display image is displayed in the image display area 10a. As shown in FIG. 14B, in the ½ field period of one field period, a black image is displayed in the image display area 10a by horizontally scanning each pixel unit 70 as described above.

  Therefore, in the second embodiment, scanning of each scanning line 112 in the image display region 10a is performed in one vertical scanning period (1/2 field period) out of two temporally continuous vertical scanning periods (1 field period). During the signal supply period, the occurrence of vertical crosstalk is suppressed for each pixel unit 70 corresponding to each data line 114, and the other vertical scanning period (one field period) of the two temporally continuous vertical scanning periods (one field period) ( In the 1/2 field period), it is possible to easily generate vertical crosstalk for each pixel unit 70 corresponding to each data line 114 during the scanning signal supply period of each scanning line 112 in the image display region 10a. Become. Therefore, also in the second embodiment, it is possible to reduce the vertical crosstalk in the display image displayed in the image display area 10a.

  Also in the second embodiment, as in the first embodiment, as a result, one display image and one black image are displayed for each field period. Accordingly, the scanning line driving circuit 104 and the data line driving circuit 101 are driven at a double speed, and as a result, on the display image, particularly in the case of a moving image, at the original frame frequency, that is, referring to FIGS. The smoothness equivalent to that when the black image as described above is not displayed and when the double-speed driving is not performed is displayed at the same frame frequency. According to the second embodiment as described above, high-quality image display can be performed on the liquid crystal panel 100.

<3: Electronic equipment>
Next, a case where the above-described liquid crystal device is applied to various electronic devices will be described.

<3-1: Projector>
First, a projector using this liquid crystal device as a light valve will be described. FIG. 15 is a plan layout diagram illustrating a configuration example of a projector. As shown in this figure, a lamp unit 1102 made of a white light source such as a halogen lamp is provided inside the projector 1100. 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 disposed in the light guide 1104, and light valves 1110R corresponding to the respective primary colors. Incident on 1110B and 1110G. These three light valves 1110R, 1110B, and 1110G are each configured using a liquid crystal module including a liquid crystal device.

  In the light valves 1110R, 1110B, and 1110G, the liquid crystal panel 100 is driven by R, G, and B primary color signals supplied from the image signal supply circuit 300, respectively. The light modulated by the liquid crystal panel 100 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 light valves 1110R, 1110B, and 1110G, the display image by the light valves 1110G needs to be horizontally reversed with respect to the display images by the light valves 1110R and 1110B.

  Note that light valves 1110R, 1110B, and 1110G receive light corresponding to the R, G, and B primary colors by the dichroic mirror 1108, and thus there is no need to provide a color filter.

<3-2: Mobile computer>
Next, an example in which the liquid crystal device is applied to a mobile personal computer will be described. FIG. 16 is a perspective view showing the configuration of this personal computer. In the figure, a computer 1200 includes a main body 1204 having 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.

<3-3: Mobile phone>
Further, an example in which the liquid crystal device is applied to a mobile phone will be described. FIG. 17 is a perspective view showing the configuration of this mobile phone. In the figure, 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. 15 to 17, 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 embodiments, and various modifications can be made as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. A driving circuit and a driving method, an electro-optical device including the driving circuit, and an 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 a liquid crystal panel. It is HH 'sectional drawing of FIG. It is a block diagram which shows the whole structure of a liquid crystal device. It is a block diagram which shows the electrical structure of a liquid crystal panel. It is a figure which shows the structural example of a scanning line drive circuit. It is explanatory drawing for demonstrating the production | generation of the image signal in an image signal supply circuit. 6 is a timing chart for explaining the operation of the scanning line driving circuit. It is a timing chart which shows a time-dependent change of the various signals for driving each data line and each scanning line. It is a figure which shows the characteristic of the N channel type TFT as a pixel switching element. FIG. 10A and FIG. 10B are explanatory views for conceptually explaining the area scanning in the first embodiment. FIG. 11A is a diagram schematically showing a display screen in the first embodiment, and FIG. 11B is a diagram schematically showing a display screen in a comparative example. It is a figure which shows the characteristic of P channel type TFT as a pixel switching element. 10 is a timing chart showing changes with time of various signals related to the operation of the liquid crystal device according to the second embodiment. FIG. 14A and FIG. 14B are explanatory diagrams for conceptually explaining horizontal scanning of each pixel unit. It is a top view which shows the structure of the projector which is an example of the electronic device to which a liquid crystal device is applied. It is a perspective view which shows the structure of the personal computer which is an example of the electronic device to which the liquid crystal 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 a liquid crystal device is applied.

Explanation of symbols

  9a ... pixel electrode, 10a ... image display area, 10 ... TFT array substrate, 20 ... counter substrate, 21 ... counter electrode, 62 ... first frame memory, 63 ... second frame memory, 70 ... pixel portion, 100 ... liquid crystal panel DESCRIPTION OF SYMBOLS 101 ... Data line drive circuit 104 ... Scan line drive circuit 112 ... Scan line 114 ... Data line 116 ... TFT 118 ... Liquid crystal element 300 ... Image signal supply circuit

Claims (16)

In the image display region on the substrate, a plurality of data lines and a plurality of scanning lines, a display element, and a one-channel type thin film transistor electrically connected to the data line and the scanning line and controlling the switching of the display element are provided. A drive circuit for driving an electro-optical device including a plurality of pixel units each including
A scanning line driving circuit for supplying a scanning signal to each of the plurality of scanning lines;
of the positive polarity and negative polarity with respect to (i) a reference potential, the thin film transistor has the positive polarity when Ru N-channel type Der, the thin film transistor has the negative polarity in the case of P-channel type and a solid signal for displaying a solid image of a specific color in the image display area and having an image signal and (ii) the image signal is different from the polarity for displaying a display image on the image display area, the data An electro-optical device drive circuit comprising: an image signal supply circuit that alternately supplies the plurality of pixel portions via a line at predetermined intervals. The drive circuit of the electro-optical device according to claim 1, wherein the image signal supply circuit supplies a black signal for displaying a black image as the solid image as the solid signal. The thin film transistor is an N-channel type,
2. The image signal supply means supplies the positive image signal and also supplies a negative black signal as the solid signal for displaying a black image as the solid image. A drive circuit for the electro-optical device according to claim 1.   The image signal supply circuit corresponds to a scan line to which the one scan signal is supplied during a period in which one of the two scan signals continuously supplied to the plurality of scan lines is supplied. The image signal is supplied to the pixel portion via the data line, and corresponds to the scanning line to which the other scanning signal is supplied during the period in which the other scanning signal is supplied among the two scanning signals. 4. The drive circuit of the electro-optical device according to claim 1, wherein the solid signal is supplied to the pixel unit through the data line. 5. The scanning line driving circuit is configured to replace the plurality of partial areas obtained by dividing the image display area with dividing lines along the scanning lines, and the plurality of partial areas in each partial area. Sequentially supplying the scanning signals to the scanning lines;
The image signal supply circuit supplies the scanning signal to one scanning line again after the scanning signal is supplied to one scanning line in each of the partial areas of the plurality of partial areas. Until the scanning signal is supplied, one of the image signal and the solid signal is supplied to the pixel portion in one of the two partial areas through the data line, and the other of the two partial areas is supplied. The drive circuit of the electro-optical device according to claim 4, wherein the other of the image signal and the solid signal is supplied to the pixel unit via the data line. The plurality of partial regions are two partial regions obtained by dividing the dividing lines so that the areas viewed in a plane are substantially equal to each other,
The scanning line driving circuit supplies the scanning signal alternately to the two partial regions and line-sequentially to the plurality of scanning lines in each partial region,
The one scanning line in the other partial region is located halfway ahead of the image display region along the data line with respect to the one scanning line in the one partial region. 6. A drive circuit for the electro-optical device according to 5.   The image signal supply circuit alternately repeats the supply of the image signal to all of the plurality of image portions and the supply of the solid signal to all of the plurality of image portions. 4. The drive circuit for the electro-optical device according to claim 3.   An electro-optical device comprising the drive circuit for the electro-optical device according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 8. In the image display region on the substrate, a plurality of data lines and a plurality of scanning lines, a display element, and a one-channel type thin film transistor electrically connected to the data line and the scanning line and controlling the switching of the display element are provided. A driving method for driving an electro-optical device including a plurality of pixel units each including:
A first step of supplying a scanning signal to each of the plurality of scanning lines;
of the positive polarity and negative polarity with respect to (i) a reference potential, the thin film transistor has the positive polarity when Ru N-channel type Der, the thin film transistor has the negative polarity in the case of P-channel type and a solid signal for displaying a solid image of a specific color in the image display area and having an image signal and (ii) the image signal is different from the polarity for displaying a display image on the image display area, the data And a second step of alternately supplying the plurality of pixel portions via a line at a predetermined cycle. The method of driving an electro-optical device according to claim 10, wherein, in the second step, a black signal for displaying a black image as the solid image is supplied as the solid signal. The thin film transistor is an N-channel type,
The said 2nd process WHEREIN: While supplying the said positive image signal, the negative black signal for displaying a black image as the said solid image is supplied as the said solid signal. A driving method of the electro-optical device according to claim.   In the second step, one of the two scanning signals continuously supplied to the plurality of scanning lines corresponds to the scanning line to which the one scanning signal is supplied in a period in which the one scanning signal is supplied. The image signal is supplied to the pixel portion via the data line, and corresponds to the scanning line to which the other scanning signal is supplied during a period in which the other scanning signal is supplied among the two scanning signals. 13. The driving method of the electro-optical device according to claim 10, wherein the solid signal is supplied to the pixel portion via the data line. In the first step, with respect to a plurality of partial areas obtained by dividing the image display area by dividing lines along the scanning lines, the plurality of scans in each partial area alternately with respect to the plurality of partial areas. Supplying the scanning signals in sequence to the lines;
In the second step, for the two partial regions that form a pair among the plurality of partial regions, after the scanning signal is supplied to one scanning line in each partial region, the scanning signal is again applied to the one scanning line. Until the scanning signal is supplied, one of the image signal and the solid signal is supplied to the pixel portion in one of the two partial areas through the data line, and the other in the other of the two partial areas. The driving method of the electro-optical device according to claim 13, wherein the other of the image signal and the solid signal is supplied to the pixel unit via the data line. In the first step, each of the plurality of partial regions is alternately arranged with respect to two partial regions obtained by dividing the plurality of partial regions so that the areas viewed in plan are substantially equal to each other by the dividing lines. Supplying the scanning signal line-sequentially to the plurality of scanning lines in a region;
The one scanning line in the other partial region is located halfway ahead of the image display region along the data line with respect to the one scanning line in the one partial region. 14. A driving method of the electro-optical device according to 14.   The supply of the image signal to all of the plurality of image portions and the supply of the solid signal to all of the plurality of image portions are alternately repeated in the second step. The driving method of the electro-optical device according to any one of the above.

Images