JP2006184380A - Electrooptical device, its driving circuit and driving method and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve moving image display quality etc. in an active matrix type electrooptical device. <P>SOLUTION: Each two rows of two hundreds and forty row scanning lines are selected twice so as to be corresponding to each column of two-row and two-column scanning patterns. For each selection, a scanning signal of a voltage according to an element of the row corresponding to the selection in the scanning pattern is supplied to two row scanning lines selected at the same time, while a data signal Xj corresponding to j-th column data line is set to a voltage according to a product sum of the element showing a display content of a pixel corresponding to an intersection of j-th column data line and two row scanning lines selected at the same time, and the element of the column corresponding to the selection in the scanning patterns. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a technique for improving the quality of moving image display in an active matrix electro-optical device.

For display panels that perform display based on optical changes in electro-optical materials such as liquid crystals, when classified by driving method, an active matrix type in which pixels are driven by switching elements, and
Although it can be divided into a passive matrix type that is driven without using a switching element, as is well known, the former active matrix type is advantageous in terms of higher definition and higher display quality. .
In such an active matrix display panel, scanning lines are selected one by one in a predetermined order, the switching element is turned on, and a voltage corresponding to the gradation of the pixel is written to the pixel through the data line. However, it has been pointed out that the display quality of moving images is lower than that of 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 the other end of the auxiliary capacitor is provided for each row. Connected to the capacitor line
After writing to the pixel capacitor, the potential of the pixel electrode is changed by shifting the potential of the capacitor line and used as a driving voltage for the pixel capacitor (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 capacitance lines are provided for each row, but a circuit for driving these capacitance lines in synchronization with the scanning lines is required separately from the scanning line driving circuit. Is complicated.
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 capable of improving the quality of moving image display, a driving circuit thereof, a driving method, and an electronic apparatus. Is to provide.

In order to achieve the above object, a driving method of an electro-optical device according to the present invention has pixels provided corresponding to intersections of a plurality of scanning lines and a plurality of columns of data lines, and the pixels are switched. An electro-optical device driving method including an element and a pixel capacitor, wherein each row of a predetermined scanning pattern composed of elements of m rows and n columns (m and n are integers of 2 or more) is represented by m rows among the plurality of rows. Are simultaneously selected n times so as to correspond to each column in the scanning pattern, and in each selection, a scanning signal corresponding to the m rows is selected as the scanning pattern. Among them, the voltage is determined according to the element of the row corresponding to the selection, the data signal for the data line of one column indicates the display content of the pixel corresponding to the intersection of the data line and the scanning line of the m row. The element and the element in the column corresponding to the selection As a voltage corresponding to the calculated value, and applying to the pixel capacitor. According to this method, the frame frequency can be increased even when the selection period is not changed as compared with the conventional configuration in which the scanning lines are selected row by row, so that the display quality of the moving image can be improved. . In other words, if the frame frequency is kept constant, the selection period can be lengthened.

In the present invention, it is preferable that the switching element is a diode having a conductor / insulator / conductor structure. Further, when a diode is used as the switching element, the selection voltage corresponding to the element of the column corresponding to the selection for the scanning line is determined based on a predetermined voltage with a positive polarity on the high side and a negative polarity on the low side. It is preferable to apply the selection voltage according to the sign of the element and to apply a selection voltage having a polarity opposite to the selection voltage to be applied before the selection voltage is applied.
Further, in the present invention, the pixel capacitor is obtained by sandwiching an electro-optical material between a pixel electrode and a counter electrode, and the switching element includes the scanning line connected to a gate,
A transistor that brings a data line and a pixel electrode into a conductive state when the scanning line is selected, and the counter electrode is divided into a plurality of pixels in a pixel region, and each divided region is a pixel positioned on a plurality of rows of scanning lines When the selection voltage is applied to the scanning lines, the scanning lines belonging to each divided region are simultaneously selected, and each divided region has a column element corresponding to the selection. It is preferable to apply a corresponding voltage.
The present invention can be conceptualized not only as a driving method for an electro-optical device but also as a driving circuit for the electro-optical device and the electro-optical device itself. Furthermore, it 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 showing the configuration of the electro-optical device according to the first 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, the liquid crystal panel 100 is provided with 240 scanning lines 312 extending in the row (X) direction and 320 data lines 212 extending in the column (Y) direction. Although details will be described later, the pixels 116 are arranged corresponding to the intersections of the scanning lines 312 and the data lines 212, respectively. Therefore, in this embodiment, the pixels 116 are 240 rows long ×
Although arranged in a matrix with 320 horizontal rows, the present invention is not limited to this.

The scanning line driving circuit 350 supplies scanning signals Y1, Y2, Y3,..., Y240 to the scanning lines 312 of the first row, the second row, the third row,. Although details will be described later, the scanning line driving circuit 350 in the present embodiment selects the scanning lines 312 in two horizontal rows in order from the top in FIG. 1 for each horizontal scanning period (1H) and the selected scanning lines. The scanning signal to 312 is a selection voltage, and the other scanning signals to the scanning line 312 are non-selection voltages (holding voltages).

The data line driving circuit 250 includes data lines 21 in the first, second, third,..., 320th columns.
2 are supplied with data signals X1, X2, X3,..., X320, respectively. Although details will be described later, the data line driving circuit 250 crosses the data line 212 and the scanning line 312 simultaneously selected by the scanning line driving circuit 350 with respect to a data signal to an arbitrary column of data lines 212. A voltage corresponding to a combination of the on / off state of the two pixels 116 positioned and the polarity of the selection voltage applied to the two selected scanning lines. The data line driving circuit 250 executes such an operation for all the data lines 212 from the first column to the 320th column.
Note that the data line driving circuit 250 has a built-in memory, and the memory includes 240 vertical rows × 32 horizontal rows.
Data defining the on / off states of the pixels 116 arranged in a matrix of 0 columns is stored, and the on / off states of the pixels 116 for two rows located on the selected scanning line are grasped from the stored contents. The display data Da is configured to be appropriately rewritten according to display contents by a host device (not shown).
The control circuit 400 controls the scanning of the liquid crystal panel 100 by supplying control signals (not shown) to the scanning line driving circuit 350 and the data line driving circuit 250.

Next, the configuration of the pixel 116 will be described. FIG. 2 is a diagram illustrating an electrical configuration of the pixel 116, and FIG. 3 is a diagram illustrating a planar configuration of the pixel 116. Here, FIG. 2 and FIG.
Are the i-th scanning line 312 and the (i−1) -th scanning line 3 adjacent to the upper scanning line 312.
12 and a data line 212 in the j-th column, and a configuration corresponding to the intersection of the data line 212 in the (j−1) -th column adjacent to the left side, for a total of 4 × 2 pixels. ing.
Note that i and (i−1) are symbols in the case of explaining without specifying the row of the scanning line 312 and are integers of 1 or more and 240 or less. Similarly, j and (j−1) are symbols used in the description without specifying the column of the data line 212, and are integers of 1 to 320.

In FIG. 2, each pixel 116 includes a pixel capacitor 118 and a TFD (thin film diode) 220 which is an example of a two-terminal switching element. Specifically, in the pixel 116 located in i row and j column, one end of the TFD 220 is connected to the data line 212 in the j column, and the other end of the TFD 220 is connected to one end of the pixel capacitor 118. Further, in the pixel 116 in i row and j column, the other end of the pixel capacitor 118 is connected to the i-th scanning line 312.

Although not particularly illustrated, the liquid crystal panel 100 has a configuration in which a pair of substrates are opposed to each other with a certain gap and the liquid crystal is sandwiched between the gaps. The positional relationship of the electrodes will be described with reference to FIG. 3. Of the pair of substrates, the opposing surface of one substrate has an IT
Rectangular pixel electrodes 234 made of a transparent conductor such as O (indium tin oxide) are arranged in a matrix. Among these, pixel electrodes 234 arranged in the same column are arranged in one column of data lines 212. These are commonly connected via the TFD 220.
Of the pair of substrates, on the opposite surface of the other substrate, a scanning line 312 that is also made of ITO or the like.
However, the stripes extend in the row direction orthogonal to the data lines 212. Here, the i-th scanning line 312 has a positional relationship so as to face each pixel electrode of the 320 pixels 116 located in the i-th row. Therefore, for example, the pixel capacitor 118 of i row and j column has the pixel electrode 234.
And the i-th scanning line 312 and the liquid crystal sandwiched between them.

Note that an alignment film (not shown) that is rubbed so as to define the initial alignment direction of the molecules of the liquid crystal is provided on the opposing surfaces of both substrates, so that the scanning line that functions as the pixel electrode 234 and the counter electrode is provided. The light passing between the light and the light 312 is rotated according to the effective voltage value applied to the liquid crystal. For this reason, for example, when polarizers having polarization axes aligned with the initial alignment direction are arranged on the incident side and the back side, respectively, if the voltage effective value is small, the amount of transmitted light decreases and white (off) display is obtained. On the other hand, if the effective voltage value is large, the amount of transmitted light increases and black (on) display is obtained (normally white mode).
Although not shown in particular, in order to prevent the contrast ratio from being lowered, the pixel electrode 2
A light shielding film is provided on at least one of the two substrates so that light passing through other than 34 is not visually recognized by an observer.

On the other hand, the data line 212 is formed of tantalum or a tantalum alloy, and branches in a T shape corresponding to each row. Although not shown, the surface of the data line 212 is covered with an insulating film formed by anodic oxidation. A branch portion from the data line 212 is electrically connected to the pixel electrode 234 and is formed so that a second conductor 226 such as chromium intersects. Accordingly, since the region where the branch portion of the data line 212 and the second conductor 226 intersect has a sandwich structure of conductor / insulator / conductor, diode switching in which the current-voltage characteristic is nonlinear in both positive and negative directions. Will have the characteristics. In the present embodiment, this intersection region is used as the TFD 220.

Here, a driving method of the electro-optical device 10 according to the present embodiment will be described. In the present embodiment, an MLS (multi line selection, also referred to as MLA) driving method that simultaneously selects a plurality of scanning lines 312 is employed. In this MLS driving method, when the voltage waveform of the scanning signal in the i-th row is a time function fi (t) and the voltage waveform of the scanning signal in the k-th row different from the i-row is a time function fk (t), The relationship is as shown in FIG. That is, the voltage waveform of the scanning signal in each row is a periodic function and has an orthonormality with each other.

In the present embodiment, a scanning pattern of 2 rows × 2 columns as shown in FIG. 5A is used as a scanning selection matrix for selecting scanning lines. In this scanning pattern, each row corresponds to the scanning line 312 that is simultaneously selected, and each column corresponds to each selection. Here, the scanning pattern may have a property that a value obtained by multiplying and summing an element in one row and an element in another arbitrary row becomes zero.
Since the scanning pattern shown in FIG. 5A has two rows and two columns, the operation of selecting two rows of scanning lines 312 at the same time is executed in two steps. Furthermore, among the elements, “+1” indicates application of a positive selection voltage during selection, and “−1” indicates application of a negative selection voltage.
In the scanning pattern of the same figure, the element in the first row and the first column is “+1”, and the element in the first row and the second column is “+”.
1 ”, a positive selection voltage is applied to one of the two scanning lines 312 selected at the same time in the first selection and a positive selection voltage is applied in the second selection. It shows that Also, the element in 2 rows and 1 column is “−1”, and the element in 2 rows and 2 columns is “+1”.
Therefore, a negative selection voltage is applied to the other of the two scanning lines 312 selected at the same time in the first selection, and a positive selection voltage is applied in the second selection. It is shown that.
If the scanning pattern shown in FIG. 5A is used in a fixed manner, a direct current component is applied to the liquid crystal. To prevent this, the elements of the scanning pattern shown in FIG. The inverted scanning pattern shown in FIG. 5B is used alternately.

The voltage waveform of the actual scanning signal will be described with reference to FIG. As described above, the scanning line driving circuit 350 performs scanning signals Y1, Y2, Y3,
..., Y240 has the following voltage waveform.
As shown in FIG. 7, in the first first vertical scanning period (1F), two rows of scanning lines 312 are obtained.
Are simultaneously selected every horizontal scanning period, and the selected scanning lines 312 are odd (1, 3, 5).
, 239) The scanning signal to the scanning line in the row becomes the positive selection voltage + V _S corresponding to the element “+1” in the first row and the first column in the scanning pattern shown in FIG. Even number (2, 4,
6,..., 240) The scanning signal to the scanning line in the row becomes the negative selection voltage -V _S corresponding to the element “−1” in the second row and the first column in the scanning pattern.
Similarly, in the second one vertical scanning period (1F), two rows of scanning lines 312 are simultaneously selected every horizontal scanning period, but scanning of the selected scanning lines 312 to odd-numbered scanning lines is performed. The signal corresponds to the element “+1” in the first row and the second column in the scanning pattern, and the positive selection voltage + V _S
Thus, the scanning signal to the even-numbered scanning line is changed to the element “2 × 2” in the scanning pattern.
Corresponding to “+1”, the positive selection voltage is + V _S.
In the subsequent third one vertical scanning period (1F), similarly, two rows of scanning lines 312 are simultaneously selected every horizontal scanning period, and scanning of the odd numbered scanning lines among the selected scanning lines 312 is performed. The signal becomes the negative selection voltage −V _S corresponding to the element “−1” in the first row and the first column in the scanning pattern shown in FIG. 5B, and the scanning signal to the even-numbered scanning line is The positive selection voltage + V _S corresponds to the element “+1” in 2 rows and 1 column in the scanning pattern.
In the third first vertical scanning period (1F), two scanning lines 312 are simultaneously selected every horizontal scanning period, and scanning signals to odd-numbered scanning lines among the selected scanning lines 312 are displayed. Corresponds to the element “−1” in the first row and the second column in the scanning pattern, and the negative selection voltage −V _S.
Thus, the scanning signal to the even-numbered scanning line is changed to the element “2 × 2” in the scanning pattern.
Corresponding to “−1”, the negative selection voltage −V _S is obtained.
That is, the voltage waveform of the scanning signal in the third and fourth one vertical scanning periods is the first
The polarity of the voltage waveform of the scanning signal in the second vertical scanning period is inverted.

Note that the selection voltage ± V _S in this embodiment is a data signal in which the TFD 220 connected to the scanning line 312 is applied to the data line 212 immediately after the selection voltage is applied to the scanning line 312. Regardless of whether the voltage is such that it is in a conductive (on) state. Further, in the present embodiment, immediately after the scanning signal becomes positive selection voltage + V _S , it becomes positive non-selection voltage (also referred to as holding voltage) + V _h and immediately after negative selection voltage −V _S. Then, the non-selective voltage of negative polarity −V _h is obtained. Here, the non-selection voltage means that the non-selection voltage is the scanning line 312.
Is a voltage that causes the TFD 220 connected to the scanning line 312 to be in a non-conductive (off) state even when applied to. The center of the selection voltage ± V _S and the non-selection voltage ± V _h is the voltage reference V _C (
= 0V), and in this embodiment, as described below, it is used only as the voltage of the data signal.

Next, the data signal will be described. As described above, the voltage of the data signal is applied to the display contents of the two pixels 116 located at the intersection with the scanning line 312 selected simultaneously with the corresponding data line 212 and the selected scanning lines of the two rows. It is determined according to the combination of the polarity of the selected voltage.
Specifically, the white (off) display of the pixel is “+1”, the black (on) display is “−1”, the positive selection voltage is “+1”, and the negative selection voltage is “ −1 ”is determined by the sum of products. In the present embodiment, two rows selected simultaneously (odd row and even row)
The display contents of the pixel are four types of on / on, on / off, off / on, off / off, and the polarity of the selection voltage is positive / negative (+1) in the first vertical scanning period.・ -1),
Positive polarity / positive polarity (+ 1 · + 1) in the second vertical scanning period, Negative polarity / positive polarity (−1 · + 1) in the third vertical scanning period, Negative polarity in the fourth vertical scanning period Negative polarity (-1 ・ -1)
Therefore, there are a total of 16 data signal voltages determined by the combination of the two as shown in FIG.
In 16 combinations, the product-sum value can be “−2”, “0”, “
Only 3 values of “+2”. Values obtained by multiplying the sum of products by a coefficient are voltages −V _X and V _C (
= 0), a + _{V X,} these voltages are used as a data signal.

As shown in FIG. 7, for example, when the pixels corresponding to the intersection of the scanning lines in the first and second rows and the data line in the j-th column are white “+1” and black “−1”, the first In the vertical scanning period, the selection voltage for the odd-numbered and even-numbered rows has a positive polarity “+1” and a negative polarity “−1”, and thus the product sum value “+2”. Therefore, when the first and second scanning lines 312 are selected and the selection voltages + V _S and −V _S are applied in the vertical scanning period, the voltage of the data signal Xj to the data line 212 in the j-th column. Becomes + V _X corresponding to the product-sum value “+2”. When the display contents of the two pixels are not changed, the voltage of the data signal Xj is selected when the first and second scanning lines 312 are selected in the second, third, and fourth vertical scanning periods. Are V _C , −V _X , and V _C depending on the product-sum value with the selection voltage, respectively.
Also, for example, the pixel corresponding to the intersection of the scanning line in the third and fourth rows and the data line in the j-th column is black “
In the case of “−1” and white “+1”, the product-sum value in the first vertical scanning period is “−2”, and thus the third and fourth scanning lines 312 are selected in the vertical scanning period. At this time, the voltage of the data signal Xj becomes −V _X corresponding to the product-sum value “−2”, and changes from the voltage + V _X at the time of selection of the first and second rows. If there is no change in the display contents of the two pixels,
In the second, third and fourth vertical scanning periods, the first and second rows of scanning lines 312
Is selected, the voltage of the data signal Xj depends on the product sum value with the selected voltage, respectively.
_C , + V _X , and V _C.

In FIG. 7, in addition to this, the pixels corresponding to the intersections of the scanning lines in the 239th and 240th rows and the data line in the jth column, and the scanning in the 1, 2, 3, 4, 239, and 240th rows. Line and (j +
1) Data signals Xj, X (j + 1) according to the display contents of the pixels corresponding to the data line in the column
Shows which voltage is used for each selection.

In such a configuration, when any one of the selection voltages + V _S and −V _S is applied to the i-th scanning line 312, the 240 pixels 116 located in the i-th row are connected in series. A difference voltage between the selection voltage and the data signal voltage is applied to both ends of the TFD 220 and the pixel capacitor 118. When this differential voltage is applied, both ends of the TFD 220 become equal to or higher than the threshold voltage Vth, so that the TFD 220 becomes conductive. For this reason, the pixel capacitor 118 in the i row and j column starts charging from a voltage corresponding to the selection voltage in the scanning signal Yi, the voltage of the data signal Xj, and the difference voltage. When the charging of the pixel capacitor 118 proceeds during the selection voltage application period and the voltage across the TFD 220 becomes equal to or lower than the threshold voltage Vth, the TFD 220 enters a non-conductive state. At this time, the charging of the pixel capacitor 118 is not performed. Will stop.

Here, the voltage Vpix held in the pixel capacitor 118 after the end of the selection period is:
Vpix = Vsel-Vth-Vsig
It can be expressed as. Vsel is a selection voltage applied to the i-th scanning line 312 and is either + V _S or −V _S , and Vsig is applied to the j-th data line 212. Signal voltage, which is either + V _X or -V _X. i-th scanning line 312
Since the charged state is maintained even when the scanning signal Yi for switching to the non-selected voltage is switched from the selected voltage, the pixel 116 in the i row and j column has a transmittance corresponding to the charged voltage.

If Va = Vsel−Vth and Vsig = k · Vb (k is a coefficient),
Vpix = Va-k ・ Vb
It becomes. Here, Va corresponds to a selection voltage in the passive driving method. Therefore, assuming that the number of simultaneously selected rows is n (n = 2 in the embodiment), 1 / n for every n rows simultaneously selected.
Duty drive. In 1 / n duty drive, the maximum contrast ratio is
Va = n ^1/2 · Vb
And the ratio of on-pixel voltage / off-pixel voltage is
{(N ^1/2 +1) / (n ^1/2 -1)} ^1/2
It becomes. Note that the ratio of the on-pixel voltage / off-pixel voltage is 2.41 when n = 2 in the embodiment, and 1.93 when n = 3, which will be described later.

Further, the effective voltage of the off pixel when n = 2 is 2.16 Vb, and the effective voltage of the off pixel when n = 3 is 4.50 Vb.
Here, when an off voltage to be applied to the pixel capacitor 118 in the case of an off pixel is expressed as Voff, if n = 2,
Vb = Voff / 2.16
So,
Va = n ^1/2 · Voff / 2.16
It becomes. For this reason,
Vsel = {n ^1/2 · Voff / 2.16} + Vth
The selection voltage and the data signal voltage may be determined so that

By the way, since the maximum contrast ratio and the ratio of the on-pixel voltage / off-pixel voltage decrease as the number n of simultaneously selected rows increases, it is actually considered that the range of 2 to 5 is preferable for n. As the liquid crystal to be used, it is preferable to use a liquid crystal having a sharp voltage-transmittance characteristic such as vertical alignment.
The actual TFD 220 has a parasitic capacitance. The voltage applied to the pixel capacitor 118 due to the influence of the parasitic capacitance shifts not less than the ideal value.
What is necessary is just to adjust a data signal voltage suitably.

As described above, according to the present embodiment, since two scanning lines 312 are selected simultaneously in one horizontal scanning period (1H), the scanning lines 312 are compared with the conventional case where the scanning lines 312 are selected one by one.
It is possible to halve the period required to select 240 rows, which is the number of lines, to 120 times as long as one horizontal scanning period (1H). For this reason, the frame frequency can be increased by shortening one vertical scanning period. Alternatively, if one vertical scanning period is fixed, it is possible to secure one horizontal scanning period, so that the selection period can be extended accordingly.
Here, increasing the frame frequency is advantageous because it tends to eliminate blurring or the like in the case of moving image display, and it is possible to emphasize writing. On the other hand, when the selection period is lengthened, the driving voltage can be lowered, which is advantageous in terms of low power consumption and the like, and a sufficient writing period can be secured. Can also be reduced.

In the embodiment, the selection voltage is applied over the selected one horizontal scanning period. However, when positive polarity writing is executed by applying the positive polarity selection voltage + V _S , Since the voltage holding state before the start of charging is different between when the positive selection voltage + V _S is applied and when a different negative selection voltage −V _S is applied, writing There may be a difference in the subsequent holding voltage. The same applies to the case where negative polarity writing is executed by applying the negative polarity selection voltage -V _S.
Therefore, as shown in FIG. 8, one horizontal scanning period 1H is divided into the first half and the second half period, and in the second half period, the selection voltage is set according to the scanning pattern, while in the first half period,
It is desirable that a selection voltage (reset voltage) having a reverse polarity is applied in advance. If such a reset voltage is applied in advance, charging of the pixel capacitor 118 can be started in a state in which the writing polarity just before is reduced, so that the brightness of each pixel is prevented from varying. It becomes possible.
In this example, a selection voltage corresponding to the scanning pattern is applied in the latter half of one horizontal scanning period, and a reset voltage having a reverse polarity is applied in advance in the immediately preceding first half period.
Without being divided into the latter half, any structure may be used as long as it is applied for substantially the same period across each row before applying the selection voltage corresponding to the scanning pattern, for example, one horizontal scanning period.

In the embodiment, the scanning line 312 is selected at the same time by using the 2 × 2 matrix shown in FIG. 5A and FIG. 5B as the scanning pattern. Not limited to this. For example, a scanning pattern composed of a 3 × 4 matrix as shown in FIG. 9A may be used. Note that the scanning matrix shown in FIG. 9A also has a property that a value obtained by multiplying and summing elements in one row and elements in another arbitrary row becomes zero.
If the scanning pattern shown in FIG. 9A is used in a fixed manner, a direct current component is applied to the liquid crystal. Therefore, the scanning pattern shown in FIG. (B
The scanning pattern shown in FIG. If two such scanning patterns are used, the operation of simultaneously selecting three rows of scanning lines 312 is executed four times and divided into eight times.

A voltage waveform of a scanning signal when such a scanning pattern is used will be described with reference to FIG.
As shown in this figure, in the first one vertical scanning period (1F), three scanning lines 31 are arranged.
2 are simultaneously selected for each horizontal scanning period, and the first series (1, 4, 7,..., 238) of the selected scanning lines 312, and the remainder when divided by 3 is “1”. The scanning signal to the scanning line belonging to (residue system) becomes the positive selection voltage + V _S corresponding to the element “+1” in the first row and the first column in the scanning pattern shown in FIG. (2, 5, 8, ..., 23
9 is a positive signal corresponding to the element “+1” in the first row and the second column in the scanning pattern. Selection voltage + V _S
The scanning signal to the scanning line belonging to the third series (remainder system in which the remainder when divided by 3 is “0”) is one line in the scanning pattern. 3 column element "
Corresponding to “+1”, the positive selection voltage is + V _S.
Similarly, in the second one vertical scanning period (1F), three rows of scanning lines 312 are simultaneously selected every horizontal scanning period, and among the selected scanning lines 312, the scanning lines belonging to the first series are selected. The scanning signal becomes the selection voltage + V _S corresponding to the element “+1” in the first row and the second column in the scanning pattern, and the scanning signal to the scanning line belonging to the second series is the element in the first row and the second column in the scanning pattern. The selection voltage −V _S corresponds to “−1”, and the scanning signal to the scanning line belonging to the third series is
The selection voltage + V _S corresponds to the element “+1” in the first row and the third column in the scanning pattern.
In the third one vertical scanning period (1F), the selection voltage of the first series of scan lines + V _S, and the selection voltage of the second series of scan lines + V _S, and the selection voltage of the third series of scan lines Is -V
_S. Further, in the fourth vertical scanning period (1F), the selection voltage of the first series of scanning lines becomes + V _S , the selection voltage of the second series of scanning lines becomes −V _S , and the third series of scanning lines. The selection voltage is −V _S.
The voltage waveform of the scanning signal in the fifth to eighth vertical scanning periods is obtained by inverting the polarity of the voltage waveform of the scanning signal in the first to fourth vertical scanning periods.

Next, data signals in the case of using the scanning pattern shown in FIGS. 9A and 9B will be described. The voltage of the data signal includes the display contents of the three pixels 116 located at the intersection with the scanning line 312 selected at the same time as the corresponding data line 212 and the polarity of the selection voltage applied to the three selected scanning lines. It is determined according to the combination.
Specifically, the white (off) display of the pixel is “+1”, the black (on) display is “−1”, the positive selection voltage is “+1”, and the negative selection voltage is “ −1 ”is determined by the sum of products.
Here, in the present embodiment, the display contents of the pixels in the three rows (first, second, and third series) selected at the same time are 2 ³ (= 8), and the polarity of the selection voltage is also the first Since there are eight patterns in the first to eighth vertical scanning periods, the voltage of the data signal determined by the combination of both is shown in FIG.
As shown in FIG.
In the 64 combinations, the product-sum values can be “−3”, “−1”,
There are only four values, “+1” and “+3”. The value obtained by multiplying the sum of products by a coefficient is the voltage −
3V _X , −V _X , + V _X , and + 3V _X , and these voltages are used as data signals.

In FIG. 11, the scanning signals of the scanning lines in the first, second, third, fourth, fifth, sixth, 238, 239, and 240th rows, these scanning lines, and the data lines in the jth and (j + 1) th columns. It also shows which voltage the data signals Xj, X (j + 1) will be in each selection according to the display content of the pixel corresponding to the intersection with.
Even when such a scanning pattern is used, a configuration in which a reverse polarity reset voltage is applied in advance before the selection voltage corresponding to the scanning pattern is applied as shown in FIG.

In the first embodiment, in the liquid crystal panel 100, the TFD 220 is connected to the data line 212.
The pixel capacitor 118 is connected to the scanning line 312 side. On the contrary, the TFD 220 is connected to the scanning line 312 side, and the pixel capacitor 118 is connected to the data line 212 side. It is also possible to use a configuration.
On the other hand, the TFD 220 is an example of a switching element. In addition to the elements using ZnO (zinc oxide) varistors, MSIs (Metal Semi-Insulators), etc.
Those connected in series or in parallel in the opposite direction can be used as switching elements.

Next, a second embodiment of the present invention will be described. In the first embodiment described above, the TFD 220 is used as the switching element. However, in the second embodiment, the TFD 220 is used as the switching element.
An FT (thin film transistor) is used. In the second embodiment, the scanning patterns shown in FIGS. 5A and 5B are alternately used as in the first embodiment.

FIG. 12 is a block diagram illustrating a configuration of the electro-optical device 10 according to the second embodiment. In this figure, the pixels 11 correspond to the scanning lines 312 of 240 rows and the data lines 212 of 320 columns.
6 is the same as that in the first embodiment, but the scanning line driving circuit is divided into a scanning line selection circuit 352 and a scanning voltage application circuit 354. In other words, the scanning line driving circuit 350 according to the first embodiment has a function of simultaneously selecting two scanning lines 312 and the selected scanning line 3.
In the second embodiment, the scanning line selection circuit 352 simultaneously selects two rows of scanning lines 312. However, in the second embodiment, the scanning line selection circuit 352 simultaneously selects two rows of scanning lines 312. The scanning voltage application circuit 354 bears the function of applying the selection voltage to the other end of the pixel capacitor.

FIG. 13 is a plan view schematically illustrating a pixel configuration of the liquid crystal panel 100 in the electro-optical device, and FIG. 14 is a diagram illustrating an electrical configuration of the liquid crystal panel 100.
The liquid crystal panel 100 according to the second embodiment is different from the first embodiment in that the pair of substrates are configured so that the electrode surfaces face each other while maintaining a certain gap and the liquid crystal is sandwiched between the gaps. Similar to the first embodiment in that the scanning line 312 and the data line 212 are provided on one of the pair of substrates, and corresponding to the intersection of the scanning line 312 and the data line 212. Pixel 116 is provided.
Specifically, as shown in FIG. 13, the pixel 116 in i row and j column includes an n-channel TFT 222 and a pixel electrode 236, and among these, the gate of the TFT 222 is the i-th scanning line. 312, its source is connected to the data line 212 in the j-th column, and its drain is connected to the pixel electrode 236.
Further, the counter electrodes 122 a and 122 are provided on the other of the pair of substrates constituting the liquid crystal panel 100.
b is provided. Among these, the counter electrode 122a is the pixel 11 from the first row to the 120th row.
6 is provided so as to face the pixel electrode 236 in common, while the counter electrode 1
22b is provided so as to face the pixel electrode 236 in the pixels 116 from the 121st row to the 240th row in common.

Therefore, in the second embodiment, as shown in FIG. 14, the pixel capacitors 118 from the first row to the 120th row are constituted by the pixel electrode 236, the counter electrode 122a, and the liquid crystal sandwiched between both electrodes, The pixel capacitors 118 from the 121st row to the 240th row are constituted by the pixel electrode 236, the counter electrode 122b, and the liquid crystal sandwiched between both electrodes.
Each pixel 116 includes a pixel capacitor 118 to a TFT 222 as shown in FIG.
In order to reduce the influence of charge leakage via the storage capacitor 119, a storage capacitor 119 is formed. One end of the storage capacitor 119 is connected to the pixel electrode 236 (the drain of the TFT 222), and the other end is commonly grounded to a potential line 123 having a constant potential, such as a power supply potential, over all pixels. The storage capacitor 119 is not shown in FIG.

Next, selection of the scanning line 312 by the scanning line selection circuit 352 will be described.
The scanning line selection circuit 352 supplies selection signals G1, G2, G3,..., G240 to the scanning lines 312 of the first row, the second row, the third row,. The order of selection is different from that of the first embodiment.
That is, as shown in FIG. 15, the selection order is the 1st and 121st lines, 2 and 1
In the 22nd, 3rd and 123rd lines, ..., the 120th and 240th lines, the counter electrode 1
The scanning line 312 facing 22a and the scanning line 312 facing the counter electrode 122b are each selected from the top. Here, the scanning line selection circuit 352 selects the scanning line 3 to be selected.
12 selection signals are set to the H level, and other selection signals of the scanning lines 312 are set to the L level.
Therefore, in one vertical scanning period, as shown in FIG. 15, the selection signals G1 and G121 become H level at the same time, and thereafter the selection signal G2 every one horizontal scanning period (1H).
, G122, selection signals G3 and G123,..., Selection signals G120 and G240 become H level, respectively.

The scanning voltage application circuit 354 applies the scanning voltage Ya to the counter electrode 122a and the scanning voltage Yb to the counter electrode 122b.
Here, the voltage waveforms of the scanning voltages Ya and Yb are as shown in FIG. That is,
In the first one vertical scanning period, the scanning voltage Ya is FIGS. 5 (a) Voltage + V _S becomes in correspondence with the element "+1" of the first row and first column in the scan pattern, the scan voltage Yb is the scan pattern The voltage is −V _S corresponding to the element “−1” in 2 rows and 1 column. Similarly, in the second one vertical scanning period, the scanning voltage Ya is the element “1 × 2” in the scanning pattern.
Corresponds to +1 ”and becomes the voltage + V _S , and the scanning voltage Yb is 2 rows 2 in the scanning pattern.
A voltage + V _S corresponding to the columns of the element "+1".
Note that the waveform of the scanning voltage in the third and fourth one vertical scanning periods is obtained by inverting the polarity of the voltage waveform of the scanning voltage in the first and second one vertical scanning periods.

Here, when the selection signal Gi supplied to the i-th scanning line 312 becomes H level, the i
Since the source and drain of the TFT 222 whose gate is connected to the scanning line 312 in the row is in a conductive state, the data signal Xj is applied to the pixel electrode 236 in the pixel 116 in the i row and j column via the TFT 222. It will be.
On the other hand, since any of the voltages + V _S and −V _S corresponding to the selection voltage in the first embodiment is applied to the counter electrodes 122a and 122b according to the scanning pattern, the pixel capacitor 118 has the first embodiment. It is applied with a voltage difference similar to the form.
Here, since the on / off state of the TFT 222 is regulated by the gate voltage (the voltage of the selection signal), the TFT 222 is not turned off during the selection period unlike the TFD 220. For this reason, the second
The scanning voltage ± V _S in the embodiment is a threshold voltage Vth higher than the selection voltage in the first embodiment.
It is sufficient to make it smaller in the absolute value direction by that amount.

The voltage determination of the data signal is the same as in the first embodiment. However, the first and 121st lines, the 2nd and 122th lines, the 3rd and 123rd lines,..., 120 and 2 are selected simultaneously.
It should be noted that the lines are separated such as the 40th line. For example, as shown in FIG. 15, in the first vertical scanning period, the scanning line selected at the same time as the first scanning line is not the second line but the 121st line.
When the pixel 116 in the first row and j column is displayed in white and the pixel 116 in the 121 row and j column is displayed in black, the voltage + V _X corresponding to the product sum value “+2” is obtained. In FIG. 15, the scanning voltage waveform to the scanning lines in the first, second, third, 120, 121, 122, 123, and 240th rows, the scanning lines, the jth column, and the (j + 1) th column. It is shown which voltage the data signals Xj, X (j + 1) will be in each selection according to the display content of the pixel corresponding to the intersection with the data line.

As described above, according to the second embodiment, similarly to the first embodiment, two rows of scanning lines 312 are simultaneously selected in one horizontal scanning period (1H). In comparison, the period required to select 240 rows, which is the number of scanning lines 312, can be halved to 120 times the period of one horizontal scanning period (1H). For this reason, the frame frequency can be increased by shortening one vertical scanning period. Alternatively, if one vertical scanning period is fixed, one horizontal scanning period can be secured, and thus the selection period can be extended.
Furthermore, according to the second embodiment, since the scanning voltage is directly applied to the counter electrodes 122a and 122b, the voltage amplitude of the data signal supplied to the data line 212 can be small. For this reason, since the TFT 222 can be reduced in size, the aperture ratio can be increased. Further, when the frame frequency is increased, the non-selection (holding) period is shortened accordingly, so that the size of the storage capacitor 119 can be reduced.

In the first and second embodiments described above, the normally white mode in which white is displayed when no voltage is applied is used. However, a normally black mode in which black is displayed when no voltage is applied may be used. In the normally black mode, it is necessary to determine the voltage of the data signal by inverting the sign with white display being “−1” and black display being “+1”.
Alternatively, color display may be performed by forming one dot with three pixels of R (red), G (green), and B (blue).
On the other hand, in the second embodiment, the counter electrode is divided into two in the vertical direction. For example, the counter electrode is divided corresponding to each row, and the odd-numbered rows are collectively driven as the counter electrode 122a, and the even-numbered rows are collectively set to the counter electrode It may be driven as 122b. In this case, it is possible to write two lines from the top. On the contrary, in the first embodiment, the case of writing two rows from the top has been described, but the order of selecting simultaneously is not limited to this.

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.
As the liquid crystal, a dye (guest) having anisotropy in absorption of visible light in the major axis direction and the minor axis direction of a molecule is dissolved in a liquid crystal (host) having a certain molecular arrangement. Alternatively, a guest-host type liquid crystal in which dye molecules are arranged 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.
However, the liquid crystal preferable for the present invention is considered to have good vertical alignment with a steep VT characteristic as described above.
The liquid crystal display device has been described so far. In the present invention, for example, EL (Electr)
onic Luminescence) elements, electron-emitting elements, electric peristaltic elements, digital mirror elements, etc., and plasma displays. Other than the liquid crystal, it is not necessary to perform AC driving, so only one of the two scanning patterns may be applied.

Next, an electronic apparatus having the electro-optical device 10 according to the above-described embodiment as a display device will be described. FIG. 16 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.

Electronic devices to which the electro-optical device 10 is applied include a digital still camera, a notebook computer, a liquid crystal television, a viewfinder type (in addition to the mobile phone shown in FIG.
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.

1 is a block diagram illustrating a configuration of an electro-optical device according to a first 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. It is a figure which shows the relationship of the voltage waveform of the scanning signal in the same electro-optical apparatus. It is a figure which shows the scanning pattern which the same electro-optical apparatus applies. It is a figure for determining the voltage of the data signal in the same electro-optical device. FIG. 6 is a diagram for explaining an operation of the electro-optical device. FIG. 6 is a diagram for explaining another operation of the electro-optical device. It is a figure which shows an example of the scanning pattern which can apply the same electro-optical apparatus. It is a figure for determining the voltage of the data signal in the same electro-optical device. FIG. 6 is a diagram for explaining another operation of the electro-optical device. FIG. 6 is a block diagram illustrating a configuration of an electro-optical device according to a second embodiment of the invention. 2 is a simplified plan view illustrating a configuration of a pixel in the electro-optical device. FIG. It is a figure which shows the structure of the pixel in the same electro-optical apparatus. FIG. 6 is a diagram for explaining an operation of the electro-optical device. 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, 212 ... Data line, 220 ...
TFD, 234, 236... Pixel electrode, 250... Data line driving circuit, 312.
0 ... scanning line driving circuit, 400 ... control circuit, 1200 ... mobile phone

Claims (7)

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 driving method of an electro-optical device including a switching element and a pixel capacitor,
Each row of a predetermined scanning pattern composed of elements of m rows and n columns (m and n are integers of 2 or more) is made to correspond to m scanning lines among the plurality of rows,
The m scanning lines are simultaneously selected n times so as to correspond to the respective columns in the scanning pattern,
For each selection,
The scanning signal corresponding to the m rows is a voltage corresponding to the element of the row corresponding to the selection in the scanning pattern,
The data signal for the data line of one column is determined according to the operation value of the element indicating the display content of the pixel corresponding to the intersection of the data line and the scanning line of m rows and the element of the column corresponding to the selection. As voltage
A method for driving an electro-optical device, comprising applying to the pixel capacitor. The method of driving an electro-optical device according to claim 1, wherein the switching element is a diode having a conductor / insulator / conductor structure. For the scan line,
The selection voltage corresponding to the element of the column corresponding to the selection is divided into a high-side positive polarity and a low-side negative polarity based on a predetermined voltage and applied according to the sign of the element, and the selection The method of driving an electro-optical device according to claim 2, wherein a selection voltage having a polarity opposite to the selection voltage to be applied is applied before the voltage is applied. The pixel capacitance is obtained by sandwiching an electro-optical material between a pixel electrode and a counter electrode,
The switching element is a transistor that connects the data line and the pixel electrode when the scan line is connected to the gate and the scan line is selected,
The counter electrode is divided into a plurality of pixel areas, and each of the divided areas is arranged to face pixel electrodes of pixels located on a plurality of rows of scanning lines,
When applying the selection voltage to the scanning lines, simultaneously select the scanning lines belonging to each divided region,
The driving method of the electro-optical device according to claim 1, wherein a voltage corresponding to an element of a column corresponding to the selection is applied to each divided region. 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 driving circuit of an electro-optical device including a switching element and a pixel capacitor,
Each row of a predetermined scanning pattern composed of elements of m rows and n columns (m and n are integers of 2 or more) is made to correspond to m scanning lines among the plurality of rows,
The m scanning lines are simultaneously selected n times so as to correspond to the respective columns in the scanning pattern,
For each simultaneous selection,
A scanning line driving circuit that sets a scanning signal corresponding to the m rows to a voltage corresponding to an element of a row corresponding to the selection in the scanning pattern;
The data signal for the data line of one column is determined according to the operation value of the element indicating the display content of the pixel corresponding to the intersection of the data line and the scanning line of m rows and the element of the column corresponding to the selection. And a data line driving circuit for applying a voltage to the pixel capacitor. 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 an electro-optical device including a switching element and a pixel capacitor,
Each row of a predetermined scanning pattern composed of elements of m rows and n columns (m and n are integers of 2 or more) is made to correspond to m scanning lines among the plurality of rows,
The m scanning lines are simultaneously selected n times so as to correspond to the respective columns in the scanning pattern,
For each selection,
A scanning line driving circuit that sets a scanning signal corresponding to the m rows to a voltage corresponding to an element of a row corresponding to the selection in the scanning pattern;
The data signal for the data line of one column is determined according to the operation value of the element indicating the display content of the pixel corresponding to the intersection of the data line and the scanning line of m rows and the element of the column corresponding to the selection. And a data line driving circuit for applying a voltage to the pixel capacitor.   An electronic apparatus comprising the electro-optical device according to claim 6.

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