JP2006163104A - Driving method of electrooptical device, electrooptical device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve dynamic image display in particular, by automatic driving without complicating constitution. <P>SOLUTION: A pixel 116 provided by corresponding to intersection of an i-th row scanning line 312 and a j-th row data line 212 includes a pixel capacity 118 and TFD 220 connected electrically serially, and an auxiliary capacity 120 interposed electrically between a (i-1)-th row scanning line selected before one row and a connection point of the pixel capacity 118 and TFD 220. When the i-th row scanning line 312 is selected, a selection voltage making TFD 220 conductive is impressed, thereafter, a non-selection voltage making TFD 220 non-conductive is impressed, and further the non-selection voltage applied on the i-th scanning line is shifted. A voltage data signal Xj corresponding to gradation of the pixel to a pixel corresponding to the selected scanning line is supplied to the j-th data line 212. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a technique for improving the quality of moving image display in an electro-optical device such as a liquid crystal display device.

In recent years, electro-optical devices that perform display by electro-optical changes such as liquid crystal have been used as cathode ray tubes (CRT).
It is widely used in various electronic devices and televisions as an alternative display device. However, it has been pointed out that this type of electro-optical device has a lower display quality of moving images than a CRT or the like.
Therefore, in recent years, the following drive technology has been proposed. In other words, this technology provides an auxiliary capacitor (storage capacitor) so as to be electrically parallel to the pixel capacitor sandwiching the liquid crystal between the pixel electrode and the common electrode, and in detail, one end is connected to the pixel electrode. In addition, the other end of the auxiliary capacitor is commonly connected to the capacitor line provided for each row, and the potential of the pixel electrode is changed by shifting the potential of the capacitor line after writing to the pixel capacitor. It is changed and used as a driving voltage for pixel capacitance (see Non-Patent Document 1).
Hiroyuki Kimura and one other, “Latest Technology for LCD for Mobile Phones”, Monthly Display, June 2004 (Vol.10 No.6), p.1-5

However, in the above technique, not only the capacitor lines are provided for each row, but also a circuit for driving these capacitor lines in synchronization with the scanning lines is required separately from the scanning line driving circuit. There is a problem of complications.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an electro-optical device that improves the quality of moving image display while avoiding problems such as a decrease in aperture ratio and a complicated configuration. To provide a driving method, an electro-optical device, and an electronic apparatus.

In order to achieve the above object, a driving method of an electro-optical device according to the invention includes pixels provided corresponding to intersections of a plurality of rows of scanning lines and a plurality of columns of data lines, and the pixels correspond to each other. A pixel capacitor and a switching element electrically connected in series between the corresponding scanning line and the corresponding data line, a scanning line selected one row before the corresponding scanning line, the pixel capacitance and the switching element A driving method of an electro-optical device including an auxiliary capacitor electrically interposed between connection points, wherein the plurality of scanning lines are selected in a predetermined order and one scanning line is selected , Applying a selection voltage for bringing the switching element into a conductive state, and then applying a non-selection voltage for bringing the switching element into a non-conduction state, and further selecting a selection voltage on the scanning line selected next to the scanning line. After applying The non-selection voltage applied to the scanning line is shifted, while a data signal having a voltage corresponding to the gradation of the pixel is supplied to the pixel corresponding to the selected scanning line via the data line. To do. According to this method, it is possible to improve the quality of moving image display while avoiding problems such as a decrease in aperture ratio and a complicated configuration.
In the present invention, the selection voltage is alternately changed for every one horizontal scanning period with respect to a positive polarity on the higher side and a negative polarity on the lower side with a predetermined reference potential as the center, and for each predetermined period with respect to the same scanning line. It is preferable to alternately change the positive polarity and the negative polarity.

The present invention can be conceptualized not only as a driving method of an electro-optical device but also as an electro-optical device. In the case of a concept as an electro-optical device, a corresponding scanning line, a pixel electrode facing the scanning line selected before the corresponding scanning line, and a liquid crystal sandwiched between the pixel electrode and both scanning lines are provided. The pixel capacitance is a capacitance of a corresponding scanning line, a facing portion of the corresponding scanning line and the pixel electrode, and a liquid crystal sandwiched between the two, and the auxiliary capacitance is more than the corresponding scanning line. The configuration is preferably a capacitance of a previously selected adjacent scanning line, a facing portion between the adjacent scanning line and the pixel electrode, and a liquid crystal sandwiched between the two. The switching element preferably has a structure of conductor / insulator / conductor.
The present invention can also be conceptualized as an electronic apparatus including the electro-optical device.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an electro-optical device according to an embodiment of the invention.
As shown in this figure, the electro-optical device 10 includes a liquid crystal panel 100, a data line driving circuit 250, a scanning line driving circuit 350, and a control circuit 400.
Among them, in the liquid crystal panel 100, 240 data lines (segment electrodes) 212 extend in the column (Y) direction, while 322 scanning lines (common electrodes) 312 extend in the row (X) direction. It is provided to do. The details of the pixel 116 will be described later.
Among the 2 and 312 rows, they are arranged corresponding to the intersections with the scanning lines 312 excluding the uppermost row and the lowermost row in the figure. Therefore, in the present embodiment, the pixel 116 has a length of 320.
The matrix is arranged in rows and 240 columns, but the present invention is not limited to this.
Note that since the pixels 116 are not provided in the uppermost and lowermost scanning lines 312, the scanning lines are dummy, but for the sake of convenience, the uppermost scanning line 312 is assumed to be the 0th row and the lowermost scanning line is scanned. The line 312 will be described as the 321st row.

The control circuit 400 controls scanning of the liquid crystal panel 100 by a latch pulse LP, a polarity instruction signal POL, a start pulse DY, a clock signal CLY, and the like. The details of the scanning control will be described each time.

The scanning line driving circuit 350 includes 0th row, 1st row, 2nd row, 3rd row,..., 320th row, 321.
Scan signals Y0, Y1, Y2, Y3,..., Y320, Y3 are respectively applied to the scanning lines 312 in the row.
12 is supplied.
Specifically, as shown in FIG. 5, the scanning line driving circuit 350 uses a start pulse DY supplied at the beginning of the vertical scanning period (1F), for example, a clock whose one period is one horizontal scanning period (1H). The signals are sequentially captured and shifted at the rising edge of the signal CLY, and these shift signals are made to correspond to the respective scanning lines 312. Then, when a certain shift signal becomes H level in one horizontal scanning period, the scanning line driving circuit 350 selects and applies a voltage to the scanning line 312 corresponding to the shift signal as follows.
That is, the scanning line driving circuit 350 scans the scanning line 3 corresponding to the shift signal that has become H level.
On the other hand, if the polarity instruction signal POL is at the H level in the selected one horizontal scanning period, the positive polarity selection voltage + V _S is selected over the one horizontal scanning period, and thereafter, the positive polarity selection voltage + VS is selected over the 1.5 horizontal scanning period. a selection of sexual non-selection voltage + V _d, further, the non-selection voltage +
A voltage (+ V _d + V _a ) shifted to the higher side by the voltage V _a than V _d is selected, and the selected voltage is applied to the scanning line 312, while the polarity indicating signal is selected in one selected horizontal scanning period. If POL is at L level, the negative selection voltage -V _S is selected over the one horizontal scanning period, and then the negative non-selection voltage -V _d is selected over the 1.5 horizontal scanning period. The voltage (−V _d −V _a ) shifted to the lower side by the voltage V _a than the non-selection voltage −V _d is selected, and the selected voltage is applied to the scanning line 312.
In this embodiment, the application period of the non-selection voltages + V _d and −V _d is 1H of one horizontal scanning period.
Since the above is sufficient, the period is set to 1.5H. In this embodiment, the reference voltage is V _C (= 0), and the higher side than the voltage V _C is positive, and the lower side is negative.

Here, the polarity instruction signal POL is a signal for designating positive polarity writing when it is at the H level, and for designating negative polarity writing when it is at the L level. As shown in FIG. (1H)
The polarity is inverted every time, and the polarity is inverted even if attention is paid to the same horizontal scanning period in the adjacent one vertical scanning period (1F). The start pulse DY, the clock signal CLY, and the polarity instruction signal POL are supplied from the control circuit 400 described above.

Next, the scanning signals Y0, Y1, Y2, Y3,.
The voltage waveforms of Y320 and Y321 will be described.
As shown in FIG. 5, the scanning signal Y0 to the scanning line 312 in the 0th row becomes the positive polarity selection voltage + V _S corresponding to the H level of the polarity instruction signal POL over one horizontal scanning period, and then the positive polarity The non-selective voltage + V _d is held for 1.5 horizontal scanning periods, and then the voltage (+ V _d +
In the case of shifting to V _a ), the first scanning line 31 (1F) has passed, and the scanning line 31 of the 0th row has passed.
When 2 is selected again, the level of the polarity instruction signal POL becomes L level which is logically inverted from the previous selection, so that the scanning signal Y0 becomes the negative polarity selection voltage −V _S and then the negative polarity non-selection. The voltage −V _d is held for 1.5 horizontal scanning periods and shifted to the voltage (−V _d −V _a ), and this cycle is repeated thereafter.
In addition, since the logic level of the polarity instruction signal POL is inverted every horizontal scanning period (1H), the scanning signal supplied to each scanning line 312 is changed every horizontal scanning period (1H), that is, the scanning line. The polarity is alternately inverted every line 312. For example, in a frame,
If the selection voltage of the scanning signal Y0 in the 0th row is the positive selection voltage + V _S , the selection voltage of the scanning signal Y1 in the 1st row becomes the negative selection voltage −V _S after one horizontal scanning period has passed. further, after a lapse of one horizontal scanning period, the selection voltage of the scanning signal Y2 in the second row is a positive polarity selection voltage + V _S.

On the other hand, gradation data Da is supplied to the data line driving circuit 250 from a host device (not shown). Here, the gradation data Da is data that designates the gradation value (brightness) of the pixel 116 with 6 bits, and the gradation value of the pixel 116 is a decimal value from “0” to “63”. Specify in 64 levels. More specifically, the darkest black display is designated when the 6-bit gradation data Dd is “0” (binary value “000000”), and gradually becomes brighter as the 6-bit decimal value increases. The gradation is specified so that the 6-bit decimal value is “63” (the binary value is “111”).
111 ″), the brightest white display is designated. Further, it is assumed that the liquid crystal panel 100 is in a normally white mode in which white display is performed when no voltage is applied.

Under such a premise, the data line driving circuit 250 determines the gradation data Da that specifies the gradation value of the pixel 116 located on the scanning line 312 selected by the scanning line driving circuit 350 according to the gradation value. The data line 2 is converted into a data signal having a voltage ± _Vd having a pulse width.
12 is supplied for one horizontal scanning period defined by the latch pulse LP. The data line driving circuit 250 executes this supply operation for each of 240 columns positioned on the selected scanning line 312 when the scanning lines 312 from the first row to the 320th row are selected. Therefore,
The data signals supplied to the data lines 212 in the first, second, third,.
Represented as X1, X2, X3,.

The relationship between the waveform of the data signal and the gradation data Da will be described with reference to FIG. FIG. 6 shows the voltage waveform of the data signal Xj supplied to the data line 212 in the j-th column (j is an integer satisfying 1 ≦ j ≦ 240) and the floor corresponding to the pixel 116 located on the selected scanning line 312. It is a figure which shows the relationship with the key data Da.
As shown in this figure, when a positive selection voltage + V _S is applied in one horizontal scanning period, the data line driving circuit 250 has a pixel 116 in the jth column located at the selection voltage + V _S.
As the corresponding gradation data Da To specify that darken the pixel, whereas the said selection voltage + V _S to prolong the application period of the reverse polarity voltage -V _d, selection of a negative polarity in one horizontal scanning period When the voltage −V _S is applied, the application period of the voltage + V _{d having} a polarity opposite to that of the selection voltage −V _S is lengthened as the gradation data Da designates the pixel to be dark.
Note that hatching in FIG. 6 indicates a period (pulse width) in which the data signal becomes an on-voltage that darkens the pixel during the period in which the selection voltage is applied, both of which are based on the end of one horizontal scanning period. The pulse width extends forward in time. Also,
In FIG. 6, only representative gradation values are displayed.

Next, the configuration of the pixel 116 will be described. FIG. 2 is a diagram illustrating an electrical configuration of the pixel 116, FIG. 3 is a diagram illustrating a planar configuration of the pixel 116, and FIG. 4 is a diagram of the liquid crystal panel 100 for illustrating the structure of the pixel 116. It is a partially broken perspective view.
2 and 3, the i-th scanning line 312, the (i−1) -th scanning line 312 adjacent thereto, the j-th data line 212, and This shows a configuration of a total of 4 pixels of 2 × 2 corresponding to the intersection with the data line 212 in the (j−1) th column adjacent on the left side. Note that i and (i−1) are symbols for generally indicating the scanning lines in which the pixels 116 are arranged, and are integers of 1 to 320.

In FIG. 2, each pixel 116 is provided corresponding to the intersection of the data line 212 and the scanning line 312 excluding the 0th and 321st rows, and includes a pixel capacitor 118, an auxiliary capacitor 120, and a two-terminal switching element. And a TFD (Thin Film Diode) 220 as an example.
In the pixel 116 located in the i row and the j column, one end of the TFD 220 is the data line 21 in the j column.
The other end of the TFD 220 is connected to one end of the pixel capacitor 118 and the auxiliary capacitor 12.
0 is connected to one end of each. Further, in the pixel 116 in the i row and j column, the other end of the pixel capacitor 118 is connected to the i-th scanning line 312 and the other end of the auxiliary capacitor 120 is the corresponding i.
It is connected to the scanning line 312 of the (i-1) th row that is selected one horizontal scanning period 1H before the row.

Next, the details of the pixel 116 will be described with reference to FIGS. 3 and 4. As shown in these figures, the liquid crystal panel 100 has a configuration in which the substrates 200 and 300 face each other while maintaining a certain gap, and the liquid crystal 160 is sandwiched between the gaps. A pixel electrode 2 made of a transparent conductor such as ITO (Indium Tin Oxide) is provided on the opposite surface of the substrate 200.
34 are arranged in a matrix, and among these, the pixel electrodes 234 arranged in the same column are commonly connected to one data line 212 via the TFD 220, respectively.
On the other hand, on the opposite surface of the substrate 300, scanning lines 312 made of ITO or the like are connected to data lines 212.
Extends in the orthogonal row direction and functions as a counter electrode.
Here, the pixel electrode 234 in the pixel 116 located in the i row and the j column is the scanning line 3 in the i row.
12 and a storage capacitor region facing the scanning line 312 in the (i-1) th row. For this reason, the pixel capacitance 118 in the pixel 116 in the i row and j column is the pixel electrode 23.
4, the pixel capacitor region, the i-th scanning line 312, and the liquid crystal 160 sandwiched between the two, while the auxiliary capacitor 120 in the pixel 116 in the same row and column includes the pixel electrode 2.
34, the auxiliary capacitance region, the scanning line 312 in the (i-1) th row, and the liquid crystal 160 sandwiched between them.

Although not particularly shown, in order to prevent the contrast ratio from being lowered, the auxiliary capacitor 1
A light shielding film is provided on at least one of the substrates 200 and 300 so that light passing through 20 is not visually recognized by an observer. In other words, it is configured such that only light passing through the pixel capacitor 118 is visually recognized by the observer.

On the other hand, when viewed from the substrate side, the TFD 220 is formed of a tantalum simple substance, a tantalum alloy, or the like, and is branched from the data line 212 into a T-shape, and the first conductor 222.
A conductor / insulator / conductor sandwich structure is formed of an insulator 224 obtained by anodizing the conductor 222 and a second conductor 226 such as chromium. For this reason,
The TFD 220 has a diode switching characteristic in which the current-voltage characteristic is nonlinear in both positive and negative directions.

Next, writing into the pixel capacitor in the electro-optical device having such a configuration will be described. FIG. 7 shows a scanning line that functions as a counter electrode in the pixel capacitor 118 of i rows and j columns (
It is a figure which shows the voltage waveform of the scanning signal Yi) and the pixel electrode 234. FIG.
When the i-th scanning line 312 is selected and the negative selection voltage −V _S is applied over one horizontal scanning period from timing t ₁ to t ₂ , the i-th scanning line 312 is applied to the j-th data line 212. Regardless of the voltage of the data signal Xj, the TFD 220 corresponding to the intersection of the scanning line 312 and the data line 212 is forcibly turned on. On the other hand, in this horizontal scanning period, the data voltage 212 is applied to the data line 212 in the j-th column according to the gradation value of the pixel in the i-th row and j-th column.
Although V _d and the data signal Xj which allocation is defined in the application period of -V _d is supplied, the liquid crystal 1
Due to the response characteristics at 60, the voltage at the pixel electrode 234 does not change abruptly and changes relatively slowly.

Next, when the selection for the i-th scanning line 312 is completed at timing t ₂ and the scanning signal Yi changes to the non-selection voltage −V _d corresponding to the negative polarity, the scanning line 312 and the data line 212 are selected. The TFD 220 corresponding to the intersection of is turned off (off). For this reason, the voltage of the pixel electrode 234 is also shifted in the voltage change direction of the scanning signal.

On the other hand, for the (i-1) scanning signal corresponding to the row scanning lines 312 Y (i-1), the timing _{t 1} the selection of the (i-1) th scanning line 312 is terminated 1. 5 horizontal scanning period elapsed timing t _3, i.e., at the timing t ₃ when the 0.5 elapsed horizontal scanning period when seen from the timing t _2, shifts to the high side from the non-selection voltage + V _S of the positive polarity by a voltage + V _a.
Since the other end of the auxiliary capacitor 120 of the pixel 116 located in the i-th row is connected to the (i-1) -th scanning line 312, the voltage of the pixel electrode 234 in the i-th row and j-th column is It changes in the voltage shift direction of the scanning line 312 in the (i−1) th row via the auxiliary capacitor 120.
Here, the voltage shift of the pixel electrode 234 is ΔV, and the pixel capacitor 118 and the auxiliary capacitor 120 are used.
When the capacitance components of _TFD 220 and TFD 220 are expressed as C _pix , C _add, and C _TFD , respectively,
ΔV = V _a × C _add / (C _add + C _pix + C _TFD ) (Equation 1)
It can be expressed as.
(I-1) The voltage shift direction of the scanning line in the row is the direction opposite to the negative polarity of the selection voltage −V _S immediately after the selection is completed, that is, the positive polarity direction, as viewed from the i-th scanning line. Therefore, the voltage shift ΔV in the pixel electrode 234 acts in the direction of increasing the voltage difference in the pixel capacitor 118.

at the timing _{t 4} when selection of i-th scanning line 312 has passed from the timing _{t 2} 1.5 horizontal scanning period ends, the scanning signal Yi, the voltage -V _a from the non-selection voltage -V _S of the negative
As the voltage shifts, the potential of the pixel voltage 234 also shifts to the lower side in the same direction, so that the state in which the voltage difference is expanded is maintained until the next selection voltage is applied. Note that the voltage shift of the scanning signal Yi increases the voltage difference in the pixel capacitance 118 of the scanning line 312 in the (i + 1) th row.
Even in the vertical scanning period in which the scanning signal Yi is applied with the positive selection voltage + Vs, the same operation is performed except that the voltage direction is reversed, and the voltage difference in the pixel capacitor 118 is increased. become.
Thus, the increase in the voltage difference between the counter electrode (scanning line 312) and the pixel electrode 234 in the pixel capacitor 118 is nothing but an increase in the effective voltage value. Incidentally, as can be seen with reference to Equation 1, as the pixel capacitance C _pix is small, the voltage V _a, it is possible to increase the [Delta] V.

In general, the pixel capacitor 118 is known to have a smaller capacitance component C _pix as it becomes _{brighter in the normally} white mode. However, in this embodiment, the pixel capacitor 118 changes from a bright state to a dark state. In the transition period until the end, an excessive amount corresponding to the pixel capacitance difference is added to the voltage shift amount ΔV of the pixel electrode 234, so that a so-called overdrive state is established, and the response time from light to dark is improved. The response time is also improved in the opposite case of dark → light. Therefore, in this embodiment, it becomes possible to display a moving image more naturally by this overdrive.

In the present embodiment, the improvement made to the pixel 116 in order to realize such overdrive is only to change the shape of the pixel electrode 234. That is, in the conventional configuration without overdrive, the auxiliary capacitor 120 does not exist, and the pixel electrode 234 faces only the scanning line (data line as will be described later) as the corresponding stripe-shaped counter electrode. In this embodiment, the shape is changed so that a part of the pixel electrode 234 also faces the scanning line selected in the previous row.
On the other hand, for the scanning signal supplied to the (i-1) -th scanning line, the non-selection voltage after the selection voltage is applied is opposite to the polarity of the selection voltage applied to the i-th scanning line. It is configured to shift in the direction. As a result, the effective voltage value of the pixel capacitor 118 in the i-th row is increased.
For this reason, according to the present embodiment, the configuration of the pixel is not complicated, and it is not necessary to provide a control line different from the scanning line 312 in order to control the auxiliary capacitance for each row. With this configuration, it is possible to receive the benefit of improving the moving image display quality by the overdrive described above.

Next, an application example of the electro-optical device 10 will be described. FIG. 8 is a block diagram illustrating a configuration of the electro-optical device 10 according to the application example. First, the difference between this application example and the embodiment is that the scanning line 312 includes a scanning line driving circuit 352 for even rows and a scanning line driving circuit 35 for odd rows.
4 and secondly, the control circuit 400 supplies the signal YSev to the scanning line driving circuit 352 for even rows, while the signal Y is supplied to the scanning line driving circuit 354 for odd rows.
The third point is that the Sod is supplied, and the third point is that the scanning signal waveform by the scanning line driving circuits 352 and 354 is changed. Note that the even-numbered row includes the 0th row of the top row.

Here, as shown in FIG. 9, the signal YSev is one of the selection voltage ± V _S and the voltage ± V _a corresponding to the selection voltage in the scanning signal of an even row in a certain vertical scanning period. This is a signal for alternately switching between one and the other every horizontal scanning period. In the next vertical scanning period, the signal YSev is switched from one of the selection voltages ± V _{S to} the other and to one of the voltages ± V _a corresponding to the selection voltage.
In one vertical scanning period, the signal YSod alternately switches the other one of the selection voltages ± V _{S and} the other one of the voltages ± V _a corresponding to the selection voltage in one row scanning period. When the signal YSev is one of the selection voltages ± V _S , the voltage ± V _a
One becomes the other, when the signal YSev is one of the voltage ± V _a, in relation of the other one of the selected voltage ± V _d. The signal YSod is also switched from the other one of the selection voltages ± V _S to one of the voltages ± V _a corresponding to the selection voltage in the next vertical scanning period.

The scanning signal waveform according to the application example will be described with reference to FIG. As shown in this figure, in the application example, when the scanning line is selected and the positive selection voltage + V _S is applied for one horizontal scanning period, the voltage −V _a is set to one horizontal scanning period after the selection. is applied over the applied thereafter, while shifting the center voltage V _C, if the negative selection voltage -V _S is applied across one horizontal scanning period, the voltage + V _a after such selection is over one horizontal scanning period And then shift to the voltage reference V _C.
Here, all the voltages ± V _a are non-selection voltages. For this reason, in the application example, the application period of the non-selection voltage from immediately after the application of the selection voltage to the voltage shift is one horizontal scanning period (1
Is H), it is shorter as compared with the embodiment, the amount of voltage shift is V _a, no difference from the embodiment.

In this application example, as in the embodiment, 0, 1, 2, 3,...
The scanning lines 312 are selected in the order of the 0th and 321st rows, and the selected voltage +
V _S and −V _S are alternately applied.
In the application example, the scanning line driving circuit 352 supplies the scanning signals Y0, Y2, Y4,..., Y320 for the scanning lines 312 in the 0th, 2nd, 4th,. ...
, The scanning line driving circuit 354 scans the scanning signals Y1, Y3, Y
5,..., Y321 are supplied, so that the scanning lines are alternately selected by the scanning line driving circuits 352 and 354 every horizontal scanning period, and the selection polarity of the scanning line driving circuit 352 in one vertical scanning period. Is fixed to one of positive polarity and negative polarity, and the selection polarity of the scanning line driving circuit 354 is fixed to the other of positive polarity and negative polarity.
Further, in the scanning line driving circuits 352 and 354, when one row of scanning lines 312 is selected,
One horizontal scanning period (1H) is left until the next scanning line is selected.

In consideration of these points, the scanning line driving circuits 352 and 354 can generate the scanning signal described above as follows.
That is, the scanning line driving circuit 352 converts even-numbered scanning lines 312 to 0, 2, 4,.
The row is selected every two horizontal scanning periods 2H in the order of the row, and the signal YSev is selected for the selected scanning line 312 over the two horizontal scanning periods 2H. In other periods, the voltage V _{C is selected.} Select.
On the other hand, the scanning line driving circuit 354 delays odd-numbered scanning lines 312 in the order of the first, third, fifth,..., 321st rows by one horizontal scanning period with respect to the selection of the scanning line driving circuit 352. In addition to selecting every two horizontal scanning periods 2H, the signal YSod is selected for the selected scanning line 312 over two horizontal scanning periods 2H, and in other periods,
To select the voltage _{V C.}

Here, when a scanning line is selected over two horizontal scanning periods, the selection is 1 for even rows and odd rows.
Although the horizontal scanning periods overlap each other, the selection voltages are not simultaneously selected by the signals YSev and YSod. Therefore, in the two horizontal scanning periods, the selection voltage is actually applied only in one half horizontal scanning period. It is. For this reason, the selection voltage application periods do not overlap.
Thus, according to the scanning line driving circuit 352 in the application example, the signal YSev or the voltage V
Any and C, and only select according to the selection of the even rows of the scanning lines, similarly, according to the scanning line driving circuit 354, either the signal YSod or voltage V _C, the odd-numbered rows of the scanning lines Therefore, the configuration can be further simplified.

In the embodiments and application examples described above, the polarity of the selection voltage is inverted every horizontal scanning period.
It may be fixed over one vertical scanning period and the selection voltage polarity of the scanning line may be made uniform over each row (however, it is necessary to periodically invert the polarity every vertical scanning period, for example). In the case of fixing in this way, the voltage shift direction after changing to the non-selection voltage in the scanning signal is reversed, but the shift direction of the (i-1) th scanning line voltage is the i-th scanning line. In view of this, there is no change in that the potential of the pixel electrode 234 is shifted in the direction opposite to the polarity of the selection voltage immediately after the selection is completed, and in the direction in which the voltage difference in the pixel capacitor 118 is enlarged.

In the embodiment, the auxiliary capacitance 120 is formed by forming the pixel electrode 234 so as to partially face not only the scanning line 312 of the corresponding row but also the scanning line 312 of the previous row. However, the present invention is not limited to this, and a separate capacity may be provided.

In the embodiment, the TFD 220 is formed on the data line 212 side, the pixel electrode 234 is formed on the TFD 220, the scanning electrode 312 facing the pixel electrode 234 forms a pixel capacitance with the liquid crystal layer interposed therebetween, and is adjacent to the pixel electrode 234. The auxiliary capacitance is formed with the scanning line and the liquid crystal layer interposed therebetween, but the TFD 220 is formed on the scanning line side, the pixel electrode 234 is formed on the TFD 220, and the data electrode 212 facing the pixel electrode 234 is formed. However, the pixel capacitance may be formed with the liquid crystal layer interposed therebetween, and the auxiliary capacitance may be formed with the adjacent scanning electrode and the insulating layer interposed therebetween. However, in this configuration, the shift direction of the non-select voltage is set to the opposite direction to that described above. As a result, the same effect can be obtained.

Further, in the embodiments and application examples, the trailing edge driving in which the on-voltage is applied while being moved backward in time is employed, but the present invention is not limited thereto, and before the on-voltage is applied while being moved forward in time. Edge driving may be employed.
In the application example according to the embodiment described above, the selection voltage is applied over one horizontal scanning period (1H). However, one horizontal scanning period is divided into the first half and the second half period, and one of these is selected. While a selection voltage is applied during a period, an on-voltage having a pulse width corresponding to a gradation value is applied as a data signal over a selection voltage application period, and an inverted voltage is supplied over the remaining period (so-called 0.5H selection). Also good.
Furthermore, in the embodiment, the normally white mode in which white is displayed in the state where no voltage is applied is described. However, a normally black mode in which black is displayed in the state where no voltage is applied may be used. In the normally black mode, the pixel becomes brighter as the pulse width is longer in the selection voltage application period.
Further, the display is not limited to the 64 gradation display, and may be a low gradation display or a higher gradation display. Furthermore, one pixel may be configured by three pixels of R (red), G (green), and B (blue) to perform color display.

The liquid crystal panel 100 is not limited to the transmissive type, and may be a reflective type or a semi-transmissive / semi-reflective type intermediate between the two. Further, in the liquid crystal panel 100, the TFD 220 is connected to the data line 212 side and the pixel capacitor 118 is connected to the scanning line 312 side.
D220 may be connected to the scanning line 312 side, and the pixel capacitor 118 may be connected to the data line 212 side.
On the other hand, the TFD 220 is an example of a switching element, and in addition to an element using a ZnO (zinc oxide) varistor, an MSI (Metal Semi-Insulator), etc., these two elements are connected in series in reverse or in parallel. A connected element or the like can be used as a switching element.

In the embodiment, the description has been given by applying the TN type as the liquid crystal. However, the STN type or a dye (guest) having anisotropy in absorption of visible light in the major axis direction and the minor axis direction of the molecule has a certain molecular arrangement. LCD (
Alternatively, a guest-host type liquid crystal in which dye molecules are aligned in parallel with liquid crystal molecules may be used. In addition, the liquid crystal molecules are aligned vertically with respect to both substrates when no voltage is applied, while the liquid crystal molecules are aligned horizontally with respect to both substrates when voltage is applied. Alternatively, liquid crystal molecules are aligned horizontally with respect to both substrates when no voltage is applied, while liquid crystal molecules are aligned vertically with respect to both substrates when voltage is applied (homogeneous alignment). It is good also as a structure of.

Next, an electronic apparatus having the electro-optical device 10 according to the above-described embodiment as a display device will be described. FIG. 10 is a perspective view showing a configuration of a mobile phone 1200 using the electro-optical device 10 according to the embodiment.
As shown in this figure, the mobile phone 1200 includes the liquid crystal panel 100 described above together with a plurality of operation buttons 1202, an earpiece 1204 and a mouthpiece 1206. In the electro-optical device 10, components other than the liquid crystal panel 100 are built in the telephone, so that they do not appear as appearance.

As an electronic apparatus to which the electro-optical device 10 is applied, in addition to the mobile phone shown in FIG. 10, a digital still camera, a notebook computer, a liquid crystal television, a viewfinder type (
Or a monitor direct view type video recorder, a car navigation device, a pager, an electronic notebook, a calculator, a word processor, a workstation, a videophone, a POS terminal, a device equipped with a touch panel, and the like. And as a display device for these various electronic devices,
Needless to say, the above-described electro-optical device 10 is applicable. In any electronic device, by shaping the waveform dullness of the scanning signal, a high-quality display can be realized with a simple configuration while suppressing a reduction in display quality.

1 is a block diagram illustrating a configuration of an electro-optical device according to an embodiment of the invention. FIG. FIG. 3 is an equivalent circuit diagram illustrating a configuration of a pixel in the electro-optical device. FIG. 3 is a plan view illustrating a configuration of a pixel in the electro-optical device. FIG. 2 is a partially broken perspective view showing a configuration of a pixel in the electro-optical device. It is a figure which shows the scanning signal by the scanning line drive circuit in the same electro-optical apparatus. It is a figure which shows the data signal by the data line drive circuit in the same electro-optical apparatus. FIG. 6 is a diagram for explaining an operation of the electro-optical device. FIG. 10 is a block diagram illustrating a configuration of an electro-optical device according to an application example of the invention. It is a figure which shows the scanning signal by the scanning line drive circuit in the same electro-optical apparatus. It is a figure which shows the structure of the mobile telephone using the electro-optical apparatus which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Liquid crystal panel, 116 ... Pixel, 118 ... Pixel capacity, 120 ... Auxiliary capacity, 160 ...
Liquid crystal, 212 ... Data line, 220 ... TFD, 234 ... Pixel electrode, 250 ... Data line drive circuit, 312 ... Scan line, 350 ... Scan line drive circuit, 400 ... Control circuit, 1200 ... Cell phone

Claims (6)

Having pixels provided corresponding to the intersection of a plurality of rows of scanning lines and a plurality of columns of data lines;
The pixel is
A pixel capacitor and a switching element electrically connected in series between a corresponding scan line and a corresponding data line;
A driving method of an electro-optical device, comprising: a scanning line selected one row before a corresponding scanning line; and an auxiliary capacitor electrically interposed between the pixel capacitor and a connection point of the switching element. There,
Selecting the plurality of rows of scanning lines in a predetermined order;
When one scanning line is selected, a selection voltage that makes the switching element conductive is applied, and then a non-selection voltage that makes the switching element non-conductive, and
After applying a selection voltage to the scanning line selected next to the scanning line, the non-selection voltage applied to one scanning line is shifted,
A driving method of an electro-optical device, characterized in that a data signal having a voltage corresponding to a gradation of the pixel is supplied to the pixel corresponding to the selected scanning line via the data line. The selection voltage is alternately changed every one horizontal scanning period with respect to a positive polarity on the higher side and a negative polarity on the lower side around a predetermined reference potential,
The method of driving an electro-optical device according to claim 1, wherein the positive polarity and the negative polarity are alternately changed at predetermined intervals for the same scanning line. A pixel provided corresponding to the intersection of a plurality of rows of scanning lines and a plurality of columns of data lines;
The scanning lines of the plurality of rows are selected in a predetermined order, and when one scanning line is selected, a selection voltage is applied to make the switching element conductive, and then the switching element is made non-conductive. A scanning line driving circuit that applies a non-selection voltage, and further shifts the non-selection voltage applied to one scanning line after applying the selection voltage to the scanning line selected next to the scanning line;
A data line driving circuit that supplies a data signal of a voltage corresponding to the gradation of the pixel to the pixel corresponding to the selected scanning line via the data line;
The pixel is
A pixel capacitor and a switching element electrically connected in series between a corresponding scan line and a corresponding data line;
An electro-optical device, comprising: a scanning line selected before a corresponding scanning line; and an auxiliary capacitor electrically interposed between the pixel capacitor and a connection point of the switching element. A pixel electrode opposed across a corresponding scan line and a scan line selected before the corresponding scan line;
A liquid crystal sandwiched between the pixel electrode and both scanning lines,
The pixel capacitance includes a corresponding scanning line, a facing portion between the corresponding scanning line and the pixel electrode,
It is the capacity with the liquid crystal sandwiched between both,
The auxiliary capacitance is a capacitance of an adjacent scanning line selected before the corresponding scanning line, a facing portion between the adjacent scanning line and the pixel electrode, and a liquid crystal sandwiched between the two. The electro-optical device according to claim 3. The electro-optical device according to claim 4, wherein the switching element has a conductor / insulator / conductor structure.   An electronic apparatus comprising the electro-optical device according to claim 3.

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