JP2004020639A - Electro-optical device and driving method for the same, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adopt an interlaced driving system to reduce the power consumption and to prevent the occurrence of jitter caused by this system to display an image of high quality in an electro-optical device. <P>SOLUTION: In the electro-optical device for driving pixel parts including pixel electrodes provided in accordance with crossing areas between scanning lines and data lines, the scanning lines are selected at intervals. A data signal representative of a gradation where one correction quantity (+ΔG) is superposed on a gradation to be originally displayed is supplied to one data line, and a data signal representative of a gradation where a correction quantity (-ΔG) other than the correction quantity (+ΔG) is superposed on the gradation to be originally displayed is supplied to another data line, and thereby, pixel parts in crossing areas between these data lines and selected scanning lines are driven. Figure shows an example of correction quantities assigned to each pixel part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of an electro-optical device, a driving method thereof, and an electronic apparatus. In particular, a liquid crystal in which a thin film diode (hereinafter, appropriately referred to as “TFD”) or the like plays a role as a switching element for a pixel. The present invention belongs to the technical field of an electro-optical device such as a device, a driving method thereof, and an electronic apparatus including the electro-optical device.
[0002]
[Background Art]
2. Description of the Related Art In recent years, electro-optical devices capable of displaying images using electro-optical changes of electro-optical materials such as liquid crystals have been widely used in various electronic devices and televisions. According to this, it is possible to enjoy a number of features that cannot be achieved by a television or the like using a conventional cathode ray tube (CRT), such as thinner, smaller, and lower power consumption.
[0003]
Many types of such electro-optical devices have already been proposed, and many of them can be classified according to appropriate criteria. For example, classification is generally made according to the driving method and the like. Specifically, it is roughly classified into an active matrix type in which pixels are driven by switching and a passive matrix type in which pixels are driven without using a switching element. Can be. Among them, the former active matrix type further includes a three-terminal type switching element such as a thin film transistor (hereinafter, appropriately referred to as a “TFT”) and a two-terminal type such as a TFD, depending on the type of the switching element. It can be roughly classified into a type using a type switching element.
[0004]
Among these, the latter electro-optical device using a two-terminal switching element such as a TFD includes a plurality of data lines as segment electrodes extending along one direction and extending along another direction intersecting the data lines. A scanning line as a common electrode, an electro-optical material such as a liquid crystal sandwiched between the data line and the scanning line (hereinafter, represented by “liquid crystal”) are provided. Thus, for example, a capacitor, that is, a liquid crystal capacitor, in which the liquid crystal is a dielectric and the pixel electrode connected to the data line and the scanning line are a pair of electrodes, is formed. The TFD is formed between the data line and the pixel electrode, and functions as a switching element for determining whether or not to apply an electric field to the liquid crystal capacitance.
[0005]
[Problems to be solved by the invention]
However, the above-described electro-optical device generally has a problem of further reducing power consumption. This is because the electro-optical device is often mounted on an electronic device such as a mobile phone that is driven by a battery. In addition, multifunctional electronic devices in recent years have spurred demands for lower power consumption of electro-optical devices. This is due to diversification of various functions (for example, moving image display) required for the electro-optical device itself for displaying an image and mounting of various devices other than the electro-optical device (for example, a sound reproducing device).
[0006]
In order to achieve such low power consumption, for example, an interlace driving method has been conventionally proposed. This is because, in the electro-optical device having the above-described configuration, not all the scanning lines are driven one by one within one field or one frame for a predetermined period, but by driving the scanning lines in a discrete manner. This is a driving method in which the driving frequency is reduced to reduce the overall power consumption.
[0007]
However, when such an interlace driving method is adopted, image unevenness called so-called jitter is displayed, so that it has not yet reached a practical stage. Here, jitter refers to image unevenness in which unevenness along a scanning line appears to move up and down on an image. This is because when a data signal is written to one pixel electrode corresponding to one scanning line, the data signal is written between the one pixel electrode and an adjacent pixel electrode corresponding to a scanning line adjacent to the one scanning line. The potential change caused by the writing occurs in the adjacent pixel electrode via the parasitic capacitance generated in the pixel electrode.
[0008]
The present invention has been made in view of the above problems, and achieves low power consumption by employing an interlaced drive system and suppresses the occurrence of image unevenness such as jitter caused by the interlace drive system. An object of the present invention is to provide an electro-optical device capable of displaying a high-quality image by doing so, a driving method thereof, and an electronic apparatus including such an electro-optical device.
[0009]
[Means for Solving the Problems]
An electro-optical device according to the present invention is an electro-optical device that drives a pixel portion including a pixel electrode provided corresponding to an intersection region between a scanning line and a data line, in order to solve the above-described problem. A scanning line drive circuit that selects all of the scanning lines over a plurality of vertical scanning periods, and one of the data lines has a correction amount of one for the gradation to be originally displayed. And a data signal representing a gray scale with which the first correction amount is superimposed on another of the data lines on a gray scale to be originally displayed. A data line driving circuit for driving the pixel portion in an intersection region of the data line and the scanning line selected by the scanning line driving circuit by supplying a data signal representing a gray scale;
[0010]
According to the electro-optical device of the present invention, first, the scanning line drive circuit selects the scanning lines in an intermittent manner, so that all of the scanning lines are selected over a plurality of vertical scanning periods. That is, so-called interlace driving is performed. According to this, in each vertical scanning period, since the driving frequency can be reduced as compared with the normal driving method of selecting all the scanning lines, it is possible to reduce the power consumption. Further, according to this driving method, crosstalk can be reduced.
[0011]
However, in such an interlace drive, as described above, image unevenness that moves up and down on an image, that is, jitter occurs, and has not been put to practical use at this stage.
[0012]
Therefore, in the present invention, the driving of the pixel portion is particularly performed as follows. That is, as described above, a data signal representing a gray level to be originally displayed to which an appropriate correction has been applied is applied to each data line that intersects the scanning lines selected at intervals. Here, “appropriate correction” means that a correction amount having a different value is superimposed on a gradation to be originally displayed along the scanning line.
[0013]
More specifically, for example, focusing on two data lines intersecting on a certain scanning line, the gray scales to be originally displayed along the scanning line are G1 and G2 according to the two data lines. Assuming that, the process of adding correction amounts having different values along the scanning line direction, for example, ΔGa and ΔGb (that is, G1 + ΔGa and G2 + ΔGb) is performed. Here, ΔGa ≠ ΔGb.
[0014]
In the data line driving circuit according to the present invention, the pixel portion is driven by supplying the data line with a data signal representing the gradation after performing such processing. That is, according to the specific example described above, a linear image having a gray scale of G1 + ΔGa and G2 + ΔGb is displayed on the scanning line.
[0015]
In the present invention, by performing such an image display, it is possible to suppress the occurrence of the jitter. This is due to the following circumstances.
[0016]
First, a mechanism of generating jitter will be briefly described. Here, for the sake of convenience, a description will be given focusing on three scanning lines, that is, first, second, and third scanning lines. First, when a data signal is written to a first pixel electrode corresponding to a first scan line, the first pixel electrode and a second pixel electrode corresponding to a second scan line adjacent to the first scan line Then, a potential change due to the writing occurs in the second pixel electrode via a parasitic capacitance generated between the second pixel electrode and the second pixel electrode. Second, when such a potential change occurs, the gray scale displayed in the pixel portion including the second pixel electrode becomes brighter or darker. It is to be noted that such light and dark unevenness is observed as a single horizontal unevenness along the second scanning line. Third, in the interlace driving employed in the present invention, during the vertical scanning period next to the vertical scanning period in which the first scanning line is selected, the selection of the second scanning line, that is, the switching of the second pixel electrode is performed. The driving of the pixel unit including the pixel is executed. Fourth, the driving of the third pixel portion causes the same potential fluctuation as described above in the third pixel electrode adjacent to the second pixel electrode. As a result, the gray scale displayed in the pixel portion including the third pixel electrode becomes bright or dark, and such uneven brightness is observed as a single horizontal unevenness along the third scanning line. become.
[0017]
For this reason, in the above example, an event occurs as if the unevenness in brightness along the second scanning line shifts to unevenness in brightness along the third scanning line. A similar phenomenon occurs in the subsequent scanning line selection, and eventually, in the above example, image unevenness that appears to move downward on the image, that is, jitter occurs.
[0018]
Therefore, in the present invention, as described above, for example, a linear image having different gradations of G1 + ΔGa and G2 + ΔGb is displayed on a scanning line, but this has the following significance. That is, considering the case where such a linear image is displayed on the first scanning line, the unevenness of brightness appearing on the second scanning line adjacent thereto includes the brightness corresponding to the correction amounts ΔGa and ΔGb. It will be. Accordingly, in such a case, the light and dark unevenness appearing along the second scanning line is not a horizontal line as described above, but is displayed in a direction intersecting the scanning line in a so-called divided manner. It will be done. That is, according to this, strictly speaking, although jitter occurs, an image is displayed in which it is difficult to visually recognize the jitter.
[0019]
As described above, according to the present invention, it is difficult to visually recognize the jitter by dividing the jitter that appears in a horizontal line on the scanning line, and, when viewed substantially, displays an image in which such jitter does not appear. It becomes possible.
[0020]
As described above, according to the present invention, by adopting the interlaced driving method, it is possible to enjoy the advantage of low power consumption, but it is possible to suppress the occurrence of jitter to obtain a high-quality image. It is possible to provide an electro-optical device that can also enjoy the advantage of displaying.
[0021]
In the present invention, the different correction amounts ΔGa and ΔGb as described above are supplied to at least “one of the data lines” and “the other of the data lines”. Here, since it is general that a large number of data lines are generally provided, these “one of the data lines” and “the other of the data lines” are defined as any one of the plurality of data lines. It means about two. More specifically, if there are data lines D1, D2, D3,... [I] The correction amount ΔGa corresponds to the data line D1, and the correction amount ΔGb corresponds to the data lines D2 and D3. Hereafter, the correction amount ΔGa corresponds to the data lines D4, D7, D10,..., And the correction amount ΔGb corresponds to the data lines D5 and D6, D8 and D9, D11 and D12,. .. Can be considered such that the correction amount ΔGa corresponds to the lines D1, D3, D5,... And the correction amount ΔGb corresponds to the data lines D2, D4, D6,. In either case, for example, it can be considered that the data line D1 corresponds to “one of the data lines” and the data line D2 corresponds to “one of the other data lines”.
[0022]
Further, in the present invention, it is necessary that at least two different amounts of correction exist, but the present invention is not limited to two. In some cases, it is needless to say that an embodiment using three or more different correction amounts is within the scope of the present invention. Further, one of the three or more different correction amounts may be set to the correction amount 0.
[0023]
In any case, the effect of dividing the jitter described above is still obtained in any of the above-described embodiments.
[0024]
In addition, the term “selection of scanning lines in an intermittent manner” according to the present invention is not limited to a mode in which every other scanning line is selected as in the above specific example. For example, a case where scanning lines are selected every two or more lines is naturally included.
[0025]
Further, in the present invention, the “gradation to be originally displayed” refers to, for example, an image signal read from an image memory connected to the electro-optical device, or a video tape or DVD on which a predetermined image signal is recorded. And the like based on image signals read from a storage medium such as a video tape player, a DVD player, or the like. In short, the gray scale in the case where the display is performed as it is without adding the correction amount according to the present invention is "the gray scale to be displayed originally".
[0026]
In addition, in order to display such gradations, a so-called pulse width modulation method can be assumed. However, the present invention is not limited to this, and a voltage amplitude modulation method may be used.
[0027]
In addition, the term “electro-optical device” as used in the present invention generally means that the state is changed by applying an appropriate electric field through energization or the like in the scanning line and the data line, and the optical Provided with an electro-optical material whose physical characteristics change.
[0028]
More specifically, examples of such an electro-optical material include a liquid crystal. In this case, when the appropriate electric field is applied to the liquid crystal, the orientation or order of the molecular assembly changes, so that the light transmittance changes. Therefore, if light is previously incident on the liquid crystal, the amount of transmitted light can be controlled, and an image can be displayed. Further, as another example of the electro-optical material, a powder EL (electroluminescence) dispersed in an appropriate binder, an inorganic or organic EL, or the like can be given. In this case, when an electric field is applied to the EL, the EL itself emits light, so that an image is displayed.
[0029]
In one aspect of the electro-optical device of the present invention, the first correction amount superimposed on a data signal written to the pixel portion in one vertical scanning period and the correction amount written to the same pixel portion in another vertical scanning period The second correction amount superimposed on the data signal to be superimposed on each other has a relationship of canceling each other.
[0030]
According to this aspect, for example, in the first vertical scanning period, odd-numbered scanning lines such as 1, 3, 5,... Are selected, and in the next vertical scanning period, 2, 4, 6,. Considering the manner in which the even-numbered scanning lines are selected as described above, in the next vertical scanning period, the odd-numbered scanning lines are usually selected again as 1, 3, 5,. become. In this case, in this case, particularly, for example, in the previous vertical scanning period, the first signal superimposed on the data signal written in the pixel portion in the intersection area between the first scanning line and a certain data line is provided. The correction amount and the second correction amount superimposed on the data signal written to the same pixel portion in the subsequent vertical scanning period have a relationship canceling each other. That is, in the subsequent vertical scanning period, the value of the second correction amount is determined so as to obtain an effect as if the first correction amount superimposed in the previous vertical scanning period was not added. It will be.
[0031]
Thus, in the present mode, it is possible to suitably realize the display of the gray level to be originally displayed.
[0032]
In this aspect, in particular, it is preferable that the first and second correction amounts have the same value and a reversed polarity.
[0033]
That is, when the first correction amount is + ΔG, the second correction amount is −ΔG. With such a configuration, for example, in a case where the gray level to be originally displayed in the pixel portion is G, in a certain vertical scanning period, the pixel portion performs a gray scale display of G + ΔG, In the vertical scanning period, the gray scale display of G-ΔG is performed, so that the net gray scale display of ((G + ΔG) + (G−ΔG)) / 2 = G is performed. It is possible to suitably realize the display of the gradation G to be displayed.
[0034]
In this manner, in the aspect using the first and second correction amounts, the value of the one correction amount matches the value of the first correction amount, and the value of the another correction amount is It is preferable to make the value equal to the value of the second correction amount.
[0035]
According to such a configuration, the types of correction amounts to be handled can be minimized, and the above-described processing can be simplified. In addition, the processing can be speeded up.
[0036]
In another aspect of the electro-optical device according to the aspect of the invention, the pixel units are arranged in a matrix, and the scanning lines and the data lines are arranged in a shape corresponding to the matrix. , Have a unique value so as to correspond to each of the pixel units.
[0037]
According to this aspect, since the correction amount has a unique value for each pixel portion, it is possible to more effectively enjoy the above-described operation effect of dividing the jitter. Further, in this aspect, for example, since it is not necessary to perform processing such as determining the value of the correction amount one by one, the above-described pixel portion driving processing according to the present invention can be simplified.
[0038]
As a specific example according to this aspect, for example, an aspect in which the correction amounts have different values along a certain scanning line, that is, first, second, and A mode in which the correction amounts ΔGa, ΔGb, and ΔGc are assigned according to the three data lines (that is, the first, second, and third pixel units) can be assumed. However, in order to satisfy the requirements of "one correction amount" and "another correction amount" in the present invention, at least two of the correction amounts of ΔGa, ΔGb, and ΔGc must have different values. . For example, it is sufficient that ΔGa ≠ ΔGb ≠ ΔGc and ΔGa ≠ ΔGc, and of course, ΔGa = ΔGb ≠ ΔGc or ΔGa ≠ ΔGb = ΔGc.
[0039]
Incidentally, since the correction amount according to the present invention is to be superimposed on the gray level to be originally displayed as described earlier, the unit is the same as that for expressing the gray level. Therefore, if a correction amount having a unique value for each pixel unit as described in this embodiment is used, and writing to the corresponding pixel unit is performed by a data signal representing the correction amount, an image corresponding to the writing is represented by ( (Although it is only conceptual). Then, the image has a predetermined pattern based on the unique value.
[0040]
In this aspect, the correction amount may have different values alternately along the scanning line.
[0041]
According to such a configuration, the correction amounts have different values alternately along the scanning lines so as to correspond to the adjacent pixel portions. In other words, according to the example described above, the first data line and the second data line are adjacent to each other, and a pair in which ΔGa ≠ ΔGb is set, and these are set in the scanning line direction. It is possible to imagine a form in which a plurality of sets are arranged along. In short, the correction amounts are arranged as ΔGa, ΔGb, ΔGa, ΔGb,.
[0042]
Therefore, the effect of dividing jitter can be more reliably enjoyed, and higher quality image display can be achieved.
[0043]
Further, in such a configuration, it is preferable that the correction amount has an alternately different value between adjacent scanning lines and along the same data line.
[0044]
According to such a configuration, when the correction amount corresponding to a certain pixel portion is ΔGa, the correction amount corresponding to a pixel portion adjacent vertically, horizontally, and vertically is ΔGb, and the correction amount corresponding to a certain pixel portion is ΔGb. If the correction amount to be performed is ΔGb, it means that the correction amount corresponding to the pixel portion adjacent vertically, horizontally, and vertically is ΔGa. In short, as described above, assuming that an image is displayed using the data signal representing the correction amount, the predetermined pattern has a checkerboard pattern.
[0045]
According to this, the effect of dividing jitter is more reliably achieved, and the predetermined pattern superimposed on the image to be displayed within one vertical scanning period based on the correction amount is a checkerboard pattern. And the display of the image can be made natural. That is, according to this aspect, it is possible to display a higher quality image.
[0046]
In another aspect of the electro-optical device of the present invention, the gray levels to be originally displayed include gray levels other than the extreme gray levels.
[0047]
According to this aspect, the gray levels to be originally displayed include gray levels other than the extreme gray levels. That is, a so-called halftone is included. According to such an aspect, it is possible to more effectively suppress the occurrence of jitter in view of the fact that the jitter appears more clearly only in the halftone.
[0048]
In another aspect of the electro-optical device of the present invention, the correction amount is not superimposed on at least one of the gray levels to be originally displayed.
[0049]
According to this aspect, for example, since the correction amount is not superimposed on at least one of the gray levels to be originally displayed, the data line to which the data signal representing the one gray level is supplied is selected. In the pixel portion in the intersection area with the scanning line, the display of the gray level to be originally displayed is performed as it is.
[0050]
At this time, it is more preferable that the at least one gradation is a gradation located at both extremes such as white or black. In this manner, in a case where the above-described white or black gradation is included in a certain image and the halftone is also included, the pixel unit that performs the halftone display that is easily affected by the jitter is included. The superimposition processing of the correction amount as described above is performed. However, since the pixel unit performing the white or black gradation display does not perform such processing, the gradation in which jitter is actually visible is Only the effect of making it difficult to visually recognize jitter can be efficiently enjoyed.
[0051]
In another aspect of the electro-optical device of the present invention, after selecting one scan line with one polarity, the scan line driving circuit inverts the next scan line to be selected with the one polarity. Select another polarity that has the same relationship.
[0052]
According to this aspect, it is possible to prevent a direct current from flowing continuously through an electro-optical material such as a liquid crystal, and to prevent the deterioration thereof.
[0053]
In another aspect of the electro-optical device of the present invention, after selecting one scanning line in one vertical scanning period with one polarity, the scanning line driving circuit selects the one scanning line next. During the vertical scanning period, the one scanning line is selected with another polarity that is in an inverse relationship to the one polarity.
[0054]
Also in this embodiment, for the same reason as described above, it is possible to prevent deterioration of the electro-optical material such as liquid crystal.
[0055]
In another aspect of the electro-optical device according to the aspect of the invention, the pixel unit may include a two-terminal switching element having one end connected to one of the scanning line and the data line; A capacitor in which an electro-optical material is held between one of the other and a pixel electrode connected to the other end of the two-terminal switching element.
[0056]
When a two-terminal switching element is used as in this embodiment, compared to a configuration using a three-terminal switching element, short-circuit failure between wirings does not occur in principle, and the manufacturing process is simplified. It is advantageous in the point and the like.
[0057]
In one aspect of the electro-optical device of the present invention, the two-terminal switching element has a structure of a conductor, an insulator, and a conductor.
[0058]
According to this aspect, one of the conductors can be used as a scanning line or a data line as it is, and the insulator can be formed by joining the conductor itself.
[0059]
In order to solve the above-described problems, a driving method of an electro-optical device according to the present invention is a driving method of an electro-optical device that drives a pixel portion including a pixel electrode provided corresponding to an intersection region between a scanning line and a data line. Selecting a scan line that is at least one or more away from a previously selected scan line during one vertical scan period; and during the selection of the scan line, one of the data lines A data signal representing a gray scale in which one correction amount is superimposed on a gray scale to be displayed is supplied, and another of the data lines is different from the one correction amount in a gray scale to be originally displayed. Supplying a data signal representing a gray scale in which another correction amount of a value is superimposed, thereby driving the pixel portion in an intersection area between the data line and the selected scanning line.
[0060]
According to the driving method of the electro-optical device of the present invention, the above-described electro-optical device of the present invention can be suitably operated. As a result, the effect of dividing jitter can be obtained, and a high-quality image can be displayed at the same time, even though low power consumption driving such as interlace driving is possible.
[0061]
In one aspect of the driving method of the electro-optical device of the present invention, a step of selecting a scanning line selected in the one vertical scanning period in another vertical scanning period, and a step of selecting the data line during the selection of the scanning line. In one, while supplying a data signal representing a gradation in which a correction amount having a relationship that cancels out the one correction amount is superimposed on a gradation to be originally displayed, and another in the data line is provided. By supplying a data signal representing a gradation in which a correction amount having a relationship that cancels with the another correction amount is superimposed on a gradation to be originally displayed, the data line and the selected scanning line are Driving the pixel portion in the intersection area.
[0062]
According to this aspect, it is possible to suitably realize the display of the gradation to be originally displayed.
[0063]
In this aspect, in particular, the one correction amount and the correction amount in a relationship that cancels with the one correction amount have a relationship in which the values are the same and the polarities are inverted, and the other correction amount and It is preferable that the correction amounts that have a relationship that cancels with the another correction amount have the same value and a reversed polarity.
[0064]
According to such a configuration, for example, one correction amount is + ΔG, and a correction amount that has a relationship to cancel this is −ΔG. In the pixel portion, only the gray level G that should be originally displayed is displayed. It will be shaped like that.
[0065]
In this configuration, furthermore, the one correction amount and the other correction amount that have a relationship that cancels each other have the same value, and the another correction amount and the one correction amount cancel each other. It is also possible to adopt a configuration in which the correction amounts having the same relationship have the same value. In this case, for example, when one correction amount is + ΔG, the correction amount that has a relationship to cancel out another correction amount is also + ΔG, and at the same time, another correction amount is −ΔG. Is also -ΔG.
[0066]
An electronic apparatus of the present invention includes the above-described electro-optical device of the present invention (including its various aspects).
[0067]
According to the electronic apparatus of the present invention, since the above-described electro-optical device of the present invention is provided, high-quality images free from image unevenness such as jitter can be generated even though low power consumption driving is possible. Various electronic devices such as a projection display device, a liquid crystal television, a mobile phone, an electronic organizer, a word processor, a viewfinder type or a monitor direct-view type video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel that can display. Can be realized.
[0068]
The operation and other advantages of the present invention will become more apparent from the embodiments explained below.
[0069]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the electro-optical device of the present invention is applied to a liquid crystal device.
[0070]
<Overview of electro-optical device>
First, an outline of an electro-optical device according to an embodiment of the present invention will be described with reference to FIGS. Hereinafter, the outline of the electro-optical device according to the present embodiment will be described after being divided into its electrical configuration and mechanical configuration.
[0071]
<Electrical configuration>
First, the electrical configuration of the electro-optical device according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing an electrical configuration of the electro-optical device according to the present embodiment.
[0072]
1, in the electro-optical device, a plurality of data lines (segment electrodes) 212 are formed extending in a column (Y) direction, while a plurality of scanning lines (common electrodes) 312 are formed in a row (X) direction. It is formed to extend. A liquid crystal, which is an example of an electro-optical material, is interposed between the data line 212 and the scanning line 312. A pixel electrode 234 (described later) and a scanning line 312 connected to the data line 212 are connected to a pair of electrodes. A liquid crystal capacitor 118 as a dielectric is formed. Further, in each intersection region between the data line 212 and the scanning line 312, a TFD 220 as a switching element for controlling application of electric charge to the liquid crystal capacitor 118 is connected in series to the liquid crystal capacitor 118. In the present embodiment, the pixel portion 116 is configured by the above-described pixel electrode 234, a part of the scanning line 312, the liquid crystal capacitor 118, and the TFD 220.
[0073]
Further, a scanning line driving circuit 350 is connected to the scanning lines 312, whereby a scanning signal is supplied to each of the scanning lines 312. More specifically, the scanning line driving circuit 350 performs an operation of “selecting” each of the plurality of scanning lines 312 in an order described later, and a selection voltage is applied to the selected scanning line 312. However, non-selection voltages are supplied to the scanning lines 312 that are not so. Further, a data line driving circuit 250 is connected to the data line 212, whereby a data signal is supplied to each of the data lines 212. In this embodiment, the number of scanning lines 312 and the number of data lines 212 are generally m and n, respectively. On the other hand, the control circuit 400 supplies grayscale data (described later), various control signals, clock signals, and the like, and controls both of them. Further, the drive voltage forming circuit 500 generates quaternary voltages of + Vs, -Vs, + Vd / 2 and -Vd / 2.
[0074]
Here, in the present embodiment, the polarity reference of the voltage applied to the scanning line 312 or the data line 212 is an intermediate voltage (virtual voltage) of the data voltage ± Vd / 2 applied to the data line 212, and is higher than this. The high potential side is a positive electrode, and the low potential side is a negative electrode. That is, the terms such as “polarity” and “inversion” used herein do not simply mean a plus voltage and a minus voltage, or a replacement thereof, but for example, a voltage between + V1 and + V2. And the exchange of + V1 and + V2 with respect to the reference voltage.
[0075]
<Mechanical configuration>
Next, a mechanical configuration of the electro-optical device according to the present embodiment will be described with reference to FIGS. FIG. 2 is a perspective view showing the entire configuration of the electro-optical device, and FIG. 3 is a partial cross-sectional view showing the configuration when the electro-optical device is broken along the X direction.
[0076]
As shown in these figures, in the electro-optical device, the opposing substrate 300 located on the observer side and the element substrate 200 located on the back side thereof are mixed with conductive particles (conductive material) 114 also serving as a spacer. The sealing material 110 is bonded at a constant interval, and a TN (Twisted Nematic) type liquid crystal 160 is sealed in the gap. The sealing material 110 is formed in a frame shape along the inner peripheral edge of the counter substrate 300 as shown in FIG. 2, and an opening 112 for enclosing the liquid crystal 160 is formed in a part thereof. ing. After the liquid crystal 160 is sealed, the opening 112 is sealed with a sealing material. Also, as can be seen from FIG. 2, the outer shape of the element substrate 200 is formed slightly larger than that of the counter substrate 300, and in a state where the two are bonded together, the former overhangs, so to speak, the latter. It looks like this.
[0077]
On the surface of the opposing substrate 300 facing the liquid crystal 160 (hereinafter, referred to as “opposing surface”), a rubbing process is performed in a predetermined direction in addition to the scanning lines 312 formed extending in the row direction. The formed alignment film 308 is formed. Here, the scanning line 312 formed on the counter substrate 300 is connected to one end of the wiring 342 formed on the element substrate 200 via the conductive particles 114 dispersed in the sealing material 110 as shown in FIG. Have been. That is, the scanning line 312 formed on the counter substrate 300 is drawn out to the element substrate 200 side via the conductive particles 114 and the wiring 342. On the other hand, a polarizer 131 is attached to the outside (observation side) of the counter substrate 300, and its absorption axis is set in accordance with the direction of the rubbing process on the alignment film 308.
[0078]
In addition, on the opposing surface of the element substrate 200, a rectangular pixel electrode 234 is formed adjacent to the data line 212 formed to extend in the Y direction, and a rubbing process is performed in a predetermined direction. An alignment film 208 is formed. On the other hand, a polarizer 121 is attached to the outside of the element substrate 200 (the side opposite to the observation side) (omitted in FIG. 2), and its absorption axis is set corresponding to the direction of the rubbing process on the alignment film 208. Have been. In addition, a backlight unit for uniformly irradiating light is provided outside the element substrate 200, but is not shown because it is not directly related to the present invention.
[0079]
Next, the outside of the display area will be described. As shown in FIG. 2, a data line driving circuit 250 for driving the data lines 212 and a scanning line are provided on two sides of the element substrate 200 projecting from the counter substrate 300. Scan line driving circuits 350 for driving the lines 312 are mounted by COG (Chip On Glass) technology. Accordingly, the data line driving circuit 250 directly supplies a data signal to the data line 212, while the scanning line driving circuit 350 indirectly transmits the scanning signal to the scanning line 312 via the wiring 342 and the conductive particles 114. It is configured so as to be supplied.
[0080]
An FPC (Flexible Printed Circuit) substrate 150 is bonded near the outside of the area where the data line driving circuit 250 is mounted, so that various signals and voltage signals from a control circuit and the like are transmitted to the scanning line driving circuit 350 and the data line. It is supplied to the line drive circuit 250.
[0081]
Note that the data line driving circuit 250 and the scanning line driving circuit 350 in FIG. 1 are located on the left side and the upper side of the electro-optical device, respectively, different from FIG. 2, but this will explain the electrical configuration. This is just a convenience measure. Further, instead of mounting the data line driving circuit 250 and the scanning line driving circuit 350 on the element substrate 200 by COG, for example, using a TAB (Tape Carrier Package) technique, the TCP on which each driving circuit is mounted is different. It may be configured to be electrically connected by an isotropic conductive film.
[0082]
<Configuration of Pixel Unit>
In the following, details of the pixel portion 116 configuring the electro-optical device having the outline as described above will be described with reference to FIG. FIG. 4 is a cutaway perspective view showing the configuration of the pixel unit 116. Note that FIG. 4 shows only the main configuration of the pixel portion 116, and does not show the alignment films 208 and 308 and the polarizers 121 and 131 shown in FIG.
[0083]
In FIG. 4, rectangular pixel electrodes 234 made of a transparent conductive material such as ITO (Indium Tin Oxide) are arranged in a matrix on the opposing surface of the element substrate 200. Among them, the pixel electrodes 234 arranged in the same column are commonly connected to one data line 212 via the TFD 220, respectively. Here, when viewed from the substrate side, the TFT 220 is formed of a tantalum simple substance, a tantalum alloy, or the like, and is branched from the data line 212 in a T-shape. It is composed of an oxidized insulator 224 and a second conductor 226 such as chromium, and has a sandwich structure of a conductor, an insulator, and a conductor. For this reason, the TFT 220 has diode switching characteristics in which the current / voltage characteristics are non-linear in both the positive and negative directions.
[0084]
Note that an insulating film 201 having transparency is formed as a base on the upper surface of the element substrate 200. This insulating film 201 is used in order to prevent the first conductor 222 from peeling off by heat treatment after the deposition of the second conductor 226 and to prevent impurities from diffusing into the first conductor 222. It is provided in. Therefore, when these do not pose a problem, the insulating film 201 can be omitted.
[0085]
On the other hand, on the opposing surface of the opposing substrate 300, scanning lines 312 made of ITO or the like are arranged in positions extending in the row direction orthogonal to the data lines 212 and opposing the pixel electrodes 234. Thus, the scanning line 312 functions as an opposite electrode of the pixel electrode 234. Therefore, the liquid crystal capacitance 118 in FIG. 1 is constituted by the scanning line 312 and the pixel electrode 234 and the liquid crystal 160 sandwiched between the data line 212 and the scanning line 312 in the intersecting region.
[0086]
In such a configuration, regardless of the data voltage applied to the data line 212, when a selection voltage for turning on the TFD 220 is applied to the scanning line 312, the TFD 220 corresponding to the intersection of the scanning line 312 and the data line 212 is activated. When turned on, charges corresponding to the difference between the selected voltage and the data voltage are accumulated in the liquid crystal capacitor 118 connected to the turned on TFD 220. After the charge accumulation, even if the non-selection voltage is applied to the scanning line 312 to turn off the TFD 220, the charge accumulation in the liquid crystal capacitor 118 is maintained.
[0087]
Here, since the alignment state of the liquid crystal 160 changes according to the amount of charge stored in the liquid crystal capacitance 118, the amount of light passing through the polarizers 121 and 131 also changes accordingly. Therefore, by controlling the amount of charge stored in the liquid crystal capacitor 118 for each pixel by the data voltage when the selection voltage is applied, a predetermined gradation display can be performed.
[0088]
<Driving method>
Hereinafter, a driving method of the electro-optical device or the pixel unit 116 configured as described above will be described. In the present embodiment, a description will be given based on a so-called four-value driving method (1H select, 1H inversion) as a drive method. Therefore, hereinafter, first, a basic description of the four-value driving method (1H select, 1H inversion) will be given, and then an embodiment in which the driving method according to the present invention is applied thereto will be described. However, the present invention is not limited to such a form, and can be similarly applied to other various driving methods (for example, a four-value driving method (1H select, 1 / 2H inversion), etc.). Needless to say,
[0089]
First, a basic description of the four-value driving method (1H select, 1H inversion) will be given. FIG. 5 shows a scanning signal Yi and a data signal Xj applied to the pixel unit 116 in i rows (an integer satisfying 1 ≦ i ≦ m) and j columns (an integer satisfying 1 ≦ j ≦ n) in this driving method. FIG. 5 is a diagram showing a waveform example of FIG.
[0090]
In the quaternary driving method shown in this figure, as the scanning signal Yi, after applying the selection voltage + Vs during one horizontal scanning period (1H), the non-selection voltage + Vd / 2 is applied during the non-selection period (holding period). When one vertical scanning period (1F) has elapsed from the selection, the operation of applying the selection voltage -Vs and applying the non-selection voltage -Vd / 2 during the non-selection period is repeated, while the voltage as the data signal Xj is repeated. One of ± Vd / 2 is applied.
[0091]
In this embodiment, when the selection voltage + Vs is applied as the scanning signal Yi to a certain scanning line 312, the selection voltage -Vs is applied as the scanning signal Yi + 1 to the scanning line 312 located in the next row. Thus, the operation of inverting the polarity of the selection voltage every one horizontal scanning period (1H) is also performed. However, this driving method is merely a basic mode, and in the present embodiment, since interlaced driving is performed as described later, after the scanning signal Yi is applied to a certain scanning line 312 (that is, the scanning line After the selection of the scanning line 312), the scanning signal Yi + n is generally applied to the scanning line 312 which is n lines away from the scanning line 312. The scanning signals Yi and Yi + n have a relationship in which the polarity is inverted. This point will be mentioned later.
[0092]
On the other hand, the voltage of the data signal Xj is a case where the selection voltage + Vs is applied, and becomes −Vd / 2 when the pixel unit 116 performs black display and + Vd / 2 when performing white display. When the selection voltage -Vs is applied, the operation is just the opposite.
[0093]
Further, in order to display a halftone between white and black, the application time of the data signal may be adjusted. For example, when performing an 8-gradation display including white and black as the extremes, assuming a time width obtained by dividing a period in which the selection voltage is applied to the scanning line 312 into seven, as shown in FIG. For example, + Vd / 2 or −Vd / 2 may be applied to two or more and six or less time periods. In this case, it is needless to say that the white display or the black display described above is a case where + Vd / 2 or -Vd / 2 is applied over all seven time widths (the uppermost stage of the data signal Xj in FIG. 6). And the bottom row). However, FIG. 6 shows the case where the selection voltage is + Vd, and when the selection voltage is -Vd, the relationship is just the opposite. More specifically, what is read may be assumed as (000), (001),..., (111) in order from the bottom in FIG.
[0094]
According to this, the effective voltage value applied to the liquid crystal capacitor 118 changes stepwise according to the time during which the data signal Xj is applied, so that the light transmittance also changes stepwise. , It is possible to display halftones.
[0095]
Note that (spq) (s, p, and q are 0 or 1) shown in the left column of FIG. 6 is the grayscale data corresponding to the data signal Xj supplied to the data line 212 in the jth column. Is represented. The plus and minus of the voltage described above correspond to the case where the electro-optical device according to the present embodiment is driven in the normally white mode. In the case of driving in the normally black mode, the above plus and minus are all reversed.
[0096]
By the way, in the above case, if each of the time widths is regarded as one unit and the mode of applying + Vd / 2 or -Vd / 2 to this one unit is regarded as "application of a pulse signal", It can be said that the halftone display as described above is realized by “pulse width modulation”.
[0097]
The above is the outline of the basic four-value driving method.
[0098]
In the present embodiment, interlace driving is performed based on such a four-value driving method. Here, the interlaced driving according to the present embodiment does not mean that the scanning lines 312 are selected one by one instead of inverting the polarity one by one for each row and selecting the scanning lines 312 as described above. It is a way to choose.
[0099]
More specifically, for example, it is as shown in FIG. In FIG. 7, in the second field (2f), after driving the scanning line 312 in the second row with the selection voltage + Vd, the scanning line 312 in the fourth row is then driven with the selection voltage -Vd. Next, the polarity of the scanning line 312 in the sixth row is inverted while the selection voltage is sequentially applied to the scanning line 312 in the even-numbered row. It is. Then, in the subsequent third field (3f), if the scanning line 312 in the first row is driven by the selection voltage −Vd, then the scanning line 312 in the third row is driven by the selection voltage + Vd. Subsequently, the polarity of the odd-numbered scanning lines 312 is sequentially reversed while the selection voltage is applied to the scanning lines 312. In this case, for example, the third scanning line 312 in the third field is driven with a positive polarity, and the scanning line 312 in the second field is driven with a negative polarity. It can be seen that driving is also realized. By the way, in the first field (1f), +,-,-, + are applied to the scanning lines 312 in the first, second, third, ... rows so that the inversion between the fields as described above is realized. , +,-,-,... Are performed (see FIG. 7). Thus, even if the scanning lines 312 are intermittently driven in the second and subsequent fields, the scanning lines 312 between the first and second scanning lines (for example, the first and third lines in the second field) can be used. It is possible to preferably realize the inversion drive and the inversion drive between the same scanning line 312 (for example, the first scanning line in the first field and the second field) between the first and second order fields. Become.
[0100]
By the way, if such an interlace driving method is applied as it is, the problem of jitter as described in the section of the background art occurs. Hereinafter, the generation mechanism will be sequentially described.
[0101]
First, as shown in FIG. 4, in the electro-optical device according to the present embodiment, each pixel portion 116 includes a pixel electrode 234. There is capacity. In this case, when the above-described selection voltage Yj is applied to a certain scanning line 312 and the data signal Xj is applied to the data line 212 (that is, when writing to the pixel portion 116 is performed), the parasitic capacitance is changed according to the change. , The potential stored in the adjacent pixel electrode 234 or the liquid crystal capacitor 118 fluctuates. That is, the portion on the image along the scanning line 312 corresponding to the adjacent pixel electrode 234 becomes brighter or darker. According to the study of the present inventor, when the scanning line 312 to be driven is driven with the opposite polarity to the scanning line 312 adjacent thereto, the image becomes dark at a portion along the adjacent scanning line 312. It has been confirmed that the image becomes brighter when driven with positive polarity.
[0102]
By the way, the interlace drive is a method of driving the scanning lines 312 at intervals as described above. According to FIG. 7, when the i-th scanning line 312 is driven in a certain field, the (i + 1) -th scanning line 312 is driven in the next field. In other words, as the field shifts, the number of rows of the driven scanning lines 312 sequentially decreases, so that the scanning lines 312 corresponding to the liquid crystal capacitors 118 that receive the above-described potential fluctuation also sequentially decrease. Will be. Specifically, for example, when the second scanning line 312 in the second field is driven, the potential of the liquid crystal capacitor 118 corresponding to the first (or third) scanning line 312 adjacent thereto changes. However, in the subsequent third field, the potential of the liquid crystal amount 118 with respect to the second (or fourth) scanning line 312 is caused by driving the third scanning line 312. Will be. Incidentally, from a different point of view, such an event can be understood as that the number of rows of the scanning lines 312 corresponding to the pixel electrodes 234 in which the potential fluctuation is caused increases as the field changes. Also means
[0103]
In any case, from the above, the shading on the image along the scanning line 312 due to the potential fluctuation via the capacitive coupling generated between the pixel electrodes 234 shifts for each field. I understand. In particular, in the case of performing interlace driving in which every other scanning line 312 is selected as shown in FIG. 7, such image unevenness changes with time in the image and changes smoothly up and down. That is, it becomes jitter. In principle, such jitter is generated everywhere on an image, and thus it is generally difficult to prevent the image quality from deteriorating.
[0104]
Therefore, in the present embodiment, the problem of the jitter is effectively solved particularly by adopting the following driving method. Hereinafter, this will be described in detail.
[0105]
First, in the present embodiment, the data signal Xj to be supplied to the data line 212 is modified. That is, as shown in FIG. 8, for example, on a certain data line 212, a data signal Xj (in FIG. 8, gray scale data (010) of FIG. 8) having one of the eight gray scales shown in FIG. In this case, an appropriate gradation conversion based on the correction amount ΔG is performed. Note that the correction amount ΔG in the present embodiment is represented by a unit representing a gradation. In FIG. 8, a time width T corresponding to the correction amount ΔG is applied to a data signal Xj having a predetermined pulse width. _ΔG Is added or subtracted to cause a change in the pulse width to correct the gradation.
[0106]
Here, the correction amount ΔG has a unique value so as to correspond to the intersection area of the scanning line 312 and the data line 212, that is, the pixel portion 116. The correction amount ΔG when focusing on one of the intersection areas has a property that the polarity is inverted for each frame. That is, when the correction amount is + ΔG in a certain one intersecting region on a certain one frame, the correction amount is −ΔG in the one intersecting region in another frame. More generally, the correction amount ΔG in a certain intersection region has a value that cancels out each other between frames for displaying one image.
[0107]
The correction amount ΔG having such an attribute is, for example, as shown in FIGS. 9A and 9B. FIG. 9 shows a case where the data signal X corresponding to the correction amount ΔG _ΔG FIG. 11 is an explanatory diagram illustrating a display example of an image when an image is displayed only by using the image display; According to FIG. 9, the property of the correction amount ΔG in the present embodiment can be visually confirmed.
[0108]
In FIG. 9, the intersecting regions of the scanning lines 312 and the data lines 212 are represented by squares, respectively. Then, the correction amount ΔG or the data signal X _ΔG Has a value that draws a checkerboard pattern in which shades alternate between adjacent squares. Note that the “shade” here means that one is + ΔG (dark) and the other is −ΔG (light). Focusing on one cell or crossing area, there is a relationship between frames (between FIGS. 9A and 9B) that cancel each other, such as + ΔG on one side and −ΔG on the other side. Understand. For example, the cell at the upper left corner in FIG. 9A is dark, and the cell at the same position in FIG. 9B is light.
[0109]
In the present embodiment, based on such a correction amount ΔG, a correction process is performed on the data signal Xj as shown in FIG. 8 according to a predetermined procedure.
[0110]
Hereinafter, this “predetermined procedure” will be described with reference to FIGS. 10, 11 and 12. FIG. 10 is an explanatory diagram showing a display example of an image to be originally displayed or to be displayed. Here, for the sake of convenience, a simple image in which the left and right half surfaces are filled with different gradations is displayed. An example is shown. FIGS. 11 and 12 show that the data signal Xj for displaying the image shown in FIG. 10 is subjected to the correction shown in FIG. 8 based on the correction amount ΔG shown in FIG. 9A or 9B. FIG. 7 is an explanatory diagram showing a display example of an image over time when an image is displayed by performing interlace driving while using the data signal Xj ′ obtained in FIG. Note that FIGS. 10, 11 and 12 each show only a very small part of the entire image. In the following, for the sake of convenience, a case where one image is displayed using the second to fifth fields when performing the interlaced driving as shown in FIG. 7 will be described.
[0111]
First, in order to finally display an image as shown in FIG. 10, in the second field, the selection voltages + Vd and -Vd are sequentially and alternately applied to the scanning lines 312 located in the even-numbered rows ( 7), a data signal Xj ′ obtained by modifying the original data signal Xj based on the correction amount ΔG shown in FIG. 9A is supplied to the data line 212.
[0112]
Then, when the second field is completed, an image as shown in FIG. 11A is displayed. As can be seen from this figure, for example, when attention is paid to the uppermost scanning line 312 in the figure, in the crossing area C1 located at the leftmost end, the gradation of the left half surface in the figure shown in FIG. Since the correction amount −ΔG at the same position is added, a display with a lighter gradation is performed. On the other hand, in the intersection area C2 on the right side in FIG. 11A, the same as shown in FIG. Since the correction amount at the position + ΔG is added, a display with a darker gradation is performed. Further, as for the right half surface of the image, the image display after the addition of the correction amounts + ΔG and −ΔG is performed in the same manner as described above, except that the reference gradation is different.
[0113]
Next, in the third field, the selection voltages -Vd and + Vd are sequentially and alternately applied to the scanning lines 312 located in the odd-numbered rows, and the data lines 212 are shown in FIG. A data signal Xj ′ taking into account the correction amount ΔG is supplied. Then, an image based on only writing to the pixel portion 116 in the third field is obtained as shown in FIG. 11B. As a result, at the stage when the third field is completed, an image as shown in FIG. 11B and an image obtained by superimposing the image shown in FIG. 11A are displayed.
[0114]
As described above, according to the above, an image in which the checkerboard pattern shown in FIG. 9A is superimposed on the image to be displayed as shown in FIG. 10 is displayed.
[0115]
Subsequently, in the fourth field, as in the second field, the selection voltages + Vd and -Vd are alternately applied to the scanning lines 312 located in the even-numbered rows again to sequentially select the scanning lines 312. Will be done. However, in the fourth field, the selection voltage -Vd (or + Vd) is applied to the scanning line 312 to which the selection voltage + Vd (or -Vd) is applied in the second field. In the fourth field, instead of using the checkered pattern shown in FIG. 9A, the pattern shown in FIG. 9B is used. That is, the data signal Xj 'is used in consideration of a pattern in which the positions of the correction amounts + [Delta] G and-[Delta] G are inverted from those in FIG. 9B.
[0116]
Then, an image based on only writing to the pixel portion 116 in the fourth field is obtained as shown in FIG. As a result, at the stage when this fourth field is completed, an image as shown in FIG. 12C and an image obtained by superimposing the previous image in FIGS. 11A and 11B are displayed. Become.
[0117]
Further, in the fifth field, as in the third field, the selection voltages + Vd and -Vd are alternately applied to the scanning lines 312 located in the odd-numbered rows again to sequentially select the scanning lines 312. At the same time, the data signal Xj ′ generated using the checkerboard pattern shown in FIG. 9B is applied to each data line 212. Then, an image based on only writing to the pixel unit 116 in the fifth field is obtained as shown in FIG. When the fifth field is completed, the image shown in FIG. 12D is superimposed on the image shown in FIG. 11A, FIG. 11B, and FIG. 12C. Will be displayed.
[0118]
As a result as described above, at this stage, substantially the same image as the originally displayed image shown in FIG. 10 is displayed. For example, focusing on the leftmost intersection area C1 of the uppermost scanning line 312 in FIGS. 11A and 12C, the gradation of the image (FIG. 10) to be originally displayed in the intersection area C1 is used. Is G, the gray scale display of G−ΔG is performed in the first field of FIG. 11A, and the gray scale display of G + ΔG is performed in the third field of FIG. 12C. It is. That is, when the average value of these two values is calculated, ((G−ΔG) + (G + ΔG)) / 2 = G, and the gradation of the image to be displayed originally can be obtained.
[0119]
By the way, especially in the writing to the pixel portion 116 from FIG. 11A to FIG. 12D, generation of the above-mentioned jitter is suppressed as much as possible. This is due to the following circumstances.
[0120]
That is, for example, in FIG. 11B, when writing the data signal Xj ′ to the pixel electrode 234 corresponding to the scanning line 312 located in the third row from the top in the figure, the pixel electrode 234 The above-described capacitive coupling occurs between the pixel electrode 234 corresponding to the scanning line 312 in the second row positioned above the drawing, so that the shape along the scanning line 312 in the second row is obtained. Causes light and dark on the image. In the above case, the third scanning line 312 in FIG. 11B and the second scanning line 312 in FIG. 11A one field before that are both driven by the selection voltage + Vd. 11 (see FIG. 7), image unevenness appearing along the second scanning line 312 in FIG. 11B, that is, jitter, is displayed as bright image unevenness.
[0121]
Here, in the present embodiment, as described above, by using the data signal Xj ′ having a gray level different by 2ΔG alternately in the scanning line 312 direction, the degree of the brightness of the jitter is adjusted according to the data signal Xj ′. It will be. That is, the jitter on the scanning line 312 in the second row appears in order from the left in the figure, such as brighter, slightly brighter, and brighter. As a result, the jitter is divided in the column direction. Will be displayed in such a way as to be displayed. Such an event is seen in FIG. 11 (a) and FIGS. 12 (a) and 12 (b) except for FIG. 11 (b).
[0122]
Further, in the present embodiment, for example, the relationship between the jitter in the second scanning line 312 in FIG. 11B and the jitter in the first scanning line 312 in FIG. It can be seen that the jitter is also divided over time. That is, the first scanning line 312 in FIG. 11A is divided in the column direction as described above in accordance with the signal writing to the pixel portion 116 corresponding to the second scanning line 312 below it. Jitter still occurs. The jitter is slightly brighter, brighter, and slightly brighter in accordance with the fact that the gradation display on the second scanning line 312 is -ΔG, + ΔG, -ΔG,... Will appear in any order. Here, when this jitter is compared with the above-mentioned jitter in the scanning line 312 in the second row in FIG. 11B along the column direction, the former which is slightly brighter becomes the latter which is brighter. What was brighter in the former is somewhat brighter in the latter. In other words, the jitter is divided even with time. This is because the correction amount ΔG was visually represented by a checkerboard pattern (see FIG. 9).
[0123]
As described above, according to the electro-optical device according to the present embodiment or the driving method thereof, first, the image unevenness, that is, the jitter, which appears to be uniform in the conventional horizontal line, corresponds to the number of the data lines 212. Since the image is displayed in such a manner as to be divided by the width, it is possible to display an image in which the jitter cannot be visually recognized.
[0124]
Further, by using the correction amount ΔG visually represented by a checkerboard pattern, it is also possible to divide the jitter over time, so that the image unevenness in which the jitter moves up and down according to the interlace driving can be obtained. This does not greatly affect the visibility, and a high-quality image can still be displayed.
[0125]
After all, in the electro-optical device according to the present embodiment, it is possible to set a situation in which it is difficult to visually recognize the jitter as described above, even though the power saving drive such as the interlace drive is possible. It is possible to display a high-quality image in which the reduction is suppressed as much as possible.
[0126]
Incidentally, the jitter appears particularly clearly when the entire image is composed of halftones. This is because, in the case of the halftone, the brightness on the image due to the fluctuation in the potential of the liquid crystal capacitor 118 via the above-described capacitance coupling is more clearly defined. Therefore, the interlace driving using the correction amount ΔG as described above is applied only to the pixel portion related to the gradation display when the gradation display in which jitter is actually observed is performed in all or a part of the image. Alternatively, depending on the case, it is more preferable to limit the display to only the case where halftone display is performed on the entire image.
[0127]
In the above embodiment, the electro-optical device that performs pulse width modulation to perform halftone display has been described, but the present invention is not limited to such an embodiment. For example, the present invention is naturally applicable to an electro-optical device having a configuration for displaying a halftone by modulating a voltage value. In the present embodiment, the actual gradation conversion is performed, as shown in FIG. 8, on the original data signal Xj with respect to the time width T based on the correction amount ΔG. _ΔG Has been achieved by adding or subtracting the correction amount ΔG or the time width T. _ΔG The present invention is not limited to the specific size of For example, in FIG. _ΔG Is a time width T corresponding to one stage such as between (000) and (001), between (001) and (010) (the distance between broken lines running up and down in the figure in FIG. 6 is proportional to it). ), But in the present invention, the time width T _ΔG Is set to, for example, the time width T (T _ΔG = T) or, depending on the case, a form (T) larger than the time width T. _ΔG > T).
[0128]
Further, in the above embodiment, the case where the interlace driving as shown in FIG. 7 is performed has been described. However, the present invention can be applied to other various forms of performing the interlace driving. . For example, in the above embodiment, the interlaced drive was performed such that two adjacent fields were defined as one unit. However, in the present invention, three or more adjacent fields were defined as one unit. Interlaced drive may be performed. Incidentally, in this case, in general, after a certain scanning line 312 is selected, a scanning line 312 separated by two or more from the certain scanning line 312 is selected.
[0129]
Furthermore, in the above-described embodiment, the correction amount ΔG has been described as having a property represented by a checkerboard pattern as shown in FIG. 9, but the present invention is limited to such a form. Do not mean. For example, in the case where the interlaced driving is performed with three fields as one unit as described above, as shown in FIG. 13, a correction amount ΔG that makes three patterns one unit is assumed. be able to. Although FIG. 13 is a diagram having the same effect as FIG. 9, only the basic unit is shown, and such a pattern is actually used in a form of being connected vertically, horizontally, and horizontally.
[0130]
In such a case, in the first pattern 1, the appearance patterns of the correction amounts + ΔG and −ΔG along the direction of the scanning line 312 are + ΔG, −ΔG, −ΔG,. , −ΔG, + ΔG, −ΔG,..., And −ΔG, −ΔG, + ΔG,. At the stage where the driving of one unit of the interlace driving (that is, for three fields) is completed, it coincides with the stage where the pattern 1 has been used, and the pattern 2 is used at the subsequent unit of the interlacing driving. Will be done. Thereafter, in the same manner, when pattern 3 has been used, the process returns to pattern 1 again.
[0131]
As described above, even in such a case, if attention is paid to one cell, there is a contribution of both the correction amounts + ΔG and −ΔG, and the net gradation G to be originally displayed is displayed. This is exactly the same as in FIG.
[0132]
In addition, it goes without saying that a correction amount ΔG in various forms can be assumed.
[0133]
(Electronics)
Next, an example in which the electro-optical device according to the above-described embodiment is used for an electronic device will be described.
[0134]
<Mobile computer>
First, an example in which the above-described electro-optical device is applied to a display unit of a personal computer will be described. FIG. 14 is a perspective view showing the configuration of this personal computer. In this figure, a computer 1100 includes a main body 1104 having a keyboard 1102 and a display device 100 used as a display. When a transmissive liquid crystal display device is used as the display device 100, a backlight (not shown) is provided on the back surface to ensure visibility in a dark place.
[0135]
<Mobile phone>
Next, an example in which the above-described electro-optical device is applied to a display unit of a mobile phone will be described. FIG. 15 is a perspective view showing the configuration of the mobile phone. In this figure, a mobile phone 1200 includes the above-described electro-optical device as a display device 100, in addition to a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206. When a liquid crystal device is used as the display device 100, in order to ensure visibility in a dark place, a backlight is used for a transmissive or transflective type, and a front light is used for a reflective type. Are also omitted).
[0136]
<Digital still camera>
Next, a digital still camera using the above-described electro-optical device for a finder will be described. FIG. 16 is a perspective view showing the back of the digital still camera. While a normal silver halide camera exposes a film with an optical image of a subject, the digital still camera 1300 generates an image signal by photoelectrically converting an optical image of the subject with an image sensor such as a CCD. Here, the above-described electro-optical device is provided as a display device 100 on the back surface of a case 1302 of the digital still camera, and performs display based on an imaging signal from a CCD. Therefore, the display device 100 functions as a finder that displays the subject. A light receiving unit 1304 including an optical lens and a CCD is provided on the front side (the rear side in the figure) of the case 1302.
[0137]
Here, when the photographer confirms the image displayed on the display device 100 and presses the shutter button 1306, the imaging signal of the CCD at that time is transferred and stored in the memory of the circuit board 1308.
[0138]
In the digital still camera 1300, a video signal output terminal 1312 and an input terminal 1314 for data communication are provided on the side of the case 1302 for external display.
[0139]
In addition, as the electronic devices, in addition to these, a liquid crystal television, a viewfinder type, a video tape recorder of a monitor direct view type, a car navigation system, a pager, an electronic notebook, a calculator, a word processor, a workstation, a videophone, a POS terminal, a touch panel And the like.
[0140]
The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention or the idea that can be read from the entirety of the claims and the specification, and an electro-optical device with such a change. Also, the driving method thereof and the electronic device are also included in the technical scope of the present invention. For example, the present invention can be applied to an electro-optical device using a three-terminal switching element such as a TFT or a passive-matrix electro-optical device. In this specification, a liquid crystal has been described as an electro-optical material. However, it is needless to say that the present invention can be applied to an electro-optical device using EL (electroluminescence).
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an electrical configuration of an electro-optical device according to an embodiment of the invention.
FIG. 2 is a perspective view showing a configuration of the electro-optical device.
FIG. 3 is a partial cross-sectional view showing a configuration when the electro-optical device is broken in an X direction.
FIG. 4 is a partially broken perspective view showing a configuration of a main part of the electro-optical device.
FIG. 5 is a diagram showing an example of waveforms of scanning signals Yi and Yi + 1 and a data signal Xj in a quaternary driving method (1H select, 1H inversion).
FIG. 6 is a diagram illustrating waveform examples of a scanning signal Yi and a data signal Xj when performing halftone display.
FIG. 7 is a diagram for explaining the interlaced driving method, and is a diagram showing which scanning line is selected for each field and what polarity is selected.
FIG. 8 is an explanatory diagram showing an example of correcting a data signal based on a correction amount according to the embodiment.
9A and 9B are diagrams illustrating a display example of an image when an image is displayed only with a data signal corresponding to a correction amount according to the embodiment, wherein FIG. 9A illustrates an example of one frame, and FIG. ) Is a diagram for another frame.
FIG. 10 is an explanatory diagram showing a display example of an image to be displayed originally.
FIG. 11 is a diagram showing an example in which an image shown in FIG. 10 is displayed by using a data signal obtained by performing a correction as shown in FIG. 8 on the basis of a correction amount shown in FIG. FIG. 9 is a diagram illustrating a display example of the image when displayed.
12 is a view subsequent to FIG. 11 and is obtained by performing a correction as shown in FIG. 8 on the data signal for displaying the image shown in FIG. 10 based on the correction amount shown in FIG. 9B. FIG. 7 is a diagram showing a display example of an image when an image is displayed using a data signal obtained.
FIG. 13 is a diagram having the same meaning as in FIG. 9 and is an explanatory diagram showing a modification of the correction amount that can be used in the present invention.
FIG. 14 is a perspective view illustrating a configuration of a personal computer as an example of an electronic apparatus to which the electro-optical device according to the embodiment is applied.
FIG. 15 is a perspective view illustrating a configuration of a mobile phone as an example of an electronic apparatus to which the electro-optical device is applied.
FIG. 16 is a perspective view showing a rear configuration of a digital still camera as an example of an electronic apparatus to which the electro-optical device is applied.
[Explanation of symbols]
116 ... Pixel part
118: liquid crystal capacitance
160 ... liquid crystal
200 …… Element substrate
212 ... data line
220 ... TFD
234 pixel electrode
250 data line drive circuit
300: Counter substrate
312 scanning line
350 scanning line drive circuit
1100 Personal computer
1200 ... mobile phone
1300 Digital still camera

Claims (17)

An electro-optical device that drives a pixel portion including a pixel electrode provided corresponding to an intersection region between a scanning line and a data line,
A scanning line driving circuit that selects all of the scanning lines over a plurality of vertical scanning periods by selecting the scanning lines intermittently;
To one of the data lines, while supplying a data signal representing a gray scale in which one correction amount is superimposed on a gray scale to be originally displayed,
To the other of the data lines, by supplying a data signal representing a gradation in which another correction amount having a value different from the one correction amount is superimposed on the gradation to be originally displayed,
An electro-optical device comprising: a data line driving circuit that drives the pixel portion in an intersection area of the data line and the scanning line selected by the scanning line driving circuit. A first correction amount superimposed on a data signal written to the pixel portion in one vertical scanning period and a second correction amount superimposed on a data signal written in the same pixel portion in another vertical scanning period The electro-optical device according to claim 1, wherein the amounts are in a mutually canceling relationship. 3. The electro-optical device according to claim 2, wherein the first and second correction amounts have the same value and a reversed polarity. 4. The value of the one correction amount is equal to the value of the first correction amount, and the value of the another correction amount is equal to the value of the second correction amount. 4. The electro-optical device according to 3. The pixel portion is arranged in a matrix, and the scanning lines and the data lines are arranged in a shape corresponding to the matrix,
The electro-optical device according to claim 1, wherein the correction amount has a unique value so as to correspond to each of the pixel units. The electro-optical device according to claim 5, wherein the correction amount has a value that is alternately different along the scanning line. 7. The electro-optical device according to claim 6, wherein the correction amount has different values alternately between adjacent scanning lines and along the same data line. The electro-optical device according to claim 1, wherein the gray levels to be displayed include gray levels other than the extreme gray levels. 9. The electro-optical device according to claim 1, wherein at least one of the tones to be displayed is supplied with a data signal in which no correction amount is superimposed. 10. The scanning line drive circuit,
After selecting one scanning line with one polarity, the next scanning line to be selected is selected with another polarity that is in an inverse relationship to the one polarity. The electro-optical device according to any one of claims 9 to 9. The scanning line drive circuit,
After selecting one scanning line in one vertical scanning period with one polarity, in the next vertical scanning period for selecting the one scanning line next, the one scanning line is connected to the one scanning line. The electro-optical device according to any one of claims 1 to 10, wherein the polarity is selected using another polarity that is in an inverse relationship with the polarity. The pixel unit includes:
A two-terminal switching element having one end connected to one of the scanning line and the data line,
A capacitor in which an electro-optical material is sandwiched between the other of the scanning line and the data line and a pixel electrode connected to the other end of the two-terminal switching element;
The electro-optical device according to claim 1, further comprising: The electro-optical device according to claim 12, wherein the two-terminal switching element has a structure of a conductor, an insulator, and a conductor. A driving method of an electro-optical device that drives a pixel portion including a pixel electrode provided corresponding to an intersection region between a scanning line and a data line,
During one vertical scan period,
Selecting a scan line that is at least one or more away from the previously selected scan line;
During the selection of the scanning line, one of the data lines is supplied with a data signal representing a gradation in which one correction amount is superimposed on a gradation to be originally displayed,
To the other of the data lines, by supplying a data signal representing a gradation in which another correction amount having a value different from the one correction amount is superimposed on the gradation to be originally displayed,
Driving the pixel portion in an intersection area of the data line and the selected scanning line. Selecting the scanning line selected in the one vertical scanning period during another vertical scanning period,
During the selection of the scanning line, a data signal representing a gray scale obtained by superimposing a correction amount having a relation to cancel out the one correction amount on a gray level to be displayed is supplied to one of the data lines. With
To the other of the data lines, by supplying a data signal representing a gray scale obtained by superimposing a correction amount that has a relationship to cancel with the another correction amount on a gray level to be originally displayed,
15. The method of driving an electro-optical device according to claim 14, further comprising: driving the pixel portion in an intersection area between the data line and the selected scanning line. The one correction amount and the correction amount in a relationship that cancels with the one correction amount have a relationship in which the values are the same and the polarities are inverted, and are different from the another correction amount and the another correction amount. 16. The driving method according to claim 15, wherein the correction amounts having a canceling relationship have the same value and a reversed polarity. An electronic apparatus comprising the electro-optical device according to claim 1.

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