JP2005258177A - Electrooptical device, drive circuit of electrooptical device, driving method of electrooptical device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize lower power consumption in what is called a partial display mode. <P>SOLUTION: In a 2nd mode wherein pixels corresponding to scanning lines in 1st to 4th and 318th to 320th rows among scanning lines in 1st to 320th rows are placed in a display state and pixels corresponding to scanning lines in the remaining 5th to 317th rows are placed in a non-display state, scanning signals Y5 to Y317 supplied to the scanning lines in the 5th to 317th rows are switched together from one of hold voltages Vd and Gnd to the other. As the scanning signals are switched in voltage, data signals are also switched from one of data voltages Vd and Gnd to the other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for reducing the power consumed by an electro-optical device.

Display devices used in portable electronic devices such as cellular phones and PDAs (personal information terminals) have an increased number of pixels so that more information can be displayed. Here, in the matrix display device, the pixels are provided corresponding to the intersections of the scanning lines and the data lines. However, as the number of pixels increases, the driving frequency of the scanning lines and the like also increases, so that power consumption is reduced. To increase.
On the other hand, due to the principle of battery driving, portable electronic devices are strongly demanded for low power consumption. Therefore, a display device used for a portable electronic device is required to have two characteristics which are contradictory at first glance: high resolution and low power consumption.
Therefore, in order to satisfy these two characteristics, when high resolution is required, the first mode is full screen display, while in the other second modes, only a partial area of the screen is displayed. Attempts have been made to reduce power consumption by making other areas non-displayed. For example, there is a technique in which the voltage of a non-selection signal supplied to each scanning line belonging to a non-display state region is inverted every one or more vertical scanning periods with reference to the voltage intermediate value of the data signal supplied to the data line. It has been proposed (see Patent Document 1).
JP 2000-276093 A

However, although the power consumption can be suppressed to a certain extent with the above-described technology, the frequency of the scanning signal and the like is the same in the first and second modes, so that the power consumption cannot be reduced as much as expected. Problem has occurred.
The present invention has been made in view of such problems, and an object of the present invention is to provide an electro-optical device, a driving circuit for the electro-optical device, a driving method for the electro-optical device, and an electronic device that can be expected to further reduce power consumption. To provide equipment.

In order to achieve the above object, a driving method of an electro-optical device according to the present invention is a pixel provided corresponding to each intersection of a plurality of scanning lines and a plurality of data lines, each of which includes a switching element and a switching element. A driving method of an electro-optical device including an electro-optical element, and having a pixel having a gradation corresponding to at least a data signal supplied to a data line when the switching element becomes conductive. A first mode in which pixels corresponding to all the scanning lines contributing to display are displayed, and a first area formed of pixels corresponding to some of the scanning lines among the plurality of scanning lines. And the second mode in which the second region composed of pixels corresponding to the remaining scanning lines is not displayed, and when the first mode is set, and the second mode Said first region at When the vertical scanning, as well as selecting the scanning lines line by line, to the selected scanning line, and applies a selection voltage to the switching element conductive,
When a data signal is supplied to the data line according to the gradation of the pixel corresponding to the intersection of the selected scanning line and the data line, and the second region is vertically scanned in the second mode, Two or more scanning lines belonging to the second region are selected, and a holding signal for turning off the switching element is applied to each of the selected scanning lines. According to this driving method, when the second region is vertically scanned in the second mode, two or more scanning lines belonging to the second region are simultaneously selected. The frequency is
Compared with the first mode, the power consumption can be reduced, and the power consumption can be reduced accordingly.

In the present invention, the data signal takes either a high-order data voltage or a low-order data voltage that is symmetric with respect to a predetermined center potential, and the selection voltage is symmetric with respect to the center potential. When there is a high-side selection voltage and a low-side selection voltage in the first mode, and when the first region is vertically scanned in the second mode, one of the selected scanning lines is selected. The high-side data voltage and the low-side data voltage are applied to the data line as data signals in accordance with the gradation of the pixel corresponding to the intersection of the selected scanning line and the data line. When the second region is vertically scanned in the second mode, the high-order data voltage is used as a data signal when distributed and supplied according to the polarity of the selection voltage applied to the selected scanning line. Also How supplied is switched from one to the other of the low-side data voltage is preferable. According to this method, since the number of times of voltage switching of the data signal is reduced as compared with the first mode, power consumption can be reduced correspondingly.

In the present invention, the data signal takes either a high-order data voltage or a low-order data voltage that is symmetric with respect to a predetermined center potential, and the selection voltage has a symmetric relation with respect to the center potential. A high-side selection voltage and a low-side selection voltage, and the holding voltage includes a high-side holding voltage and a low-side holding voltage that are symmetrical with respect to the center potential, and is in the first mode. And, when the first region is vertically scanned in the second mode, one selected voltage is applied to the selected scanning line in one period obtained by dividing one horizontal scanning period into two, One holding voltage is applied in the other period obtained by dividing one horizontal scanning period into two, and the higher-side data voltage and the lower voltage are applied to the data line in one period obtained by dividing one horizontal scanning period into two. The side data voltage is distributed and supplied according to the polarity of the selection voltage applied to the selected scanning line according to the gradation of the pixel corresponding to the intersection of the selected scanning line and the data line. In the other period obtained by dividing the horizontal scanning period into two periods, the lower data voltage is applied substantially during the same period as the period in which the higher data voltage is applied in one period, and the lower data voltage is applied in one period. When a high-side data voltage is applied over substantially the same period and the second region is vertically scanned in the second mode, the high-side holding voltage or the low-side holding voltage is applied to the selected scanning line. Switch from one to the other,
The data signal may be supplied by switching from one of the high-order data voltage and the low-order data voltage to the other. According to this method, since the pixel is AC driven with the center potential as a reference, deterioration due to application of a DC component can be prevented, and the effective voltage value applied to the pixel during the holding period depends on display contents. Therefore, the display difference due to off-leakage can be eliminated.

Furthermore, in the present invention, it is preferable that the period for selecting the scanning lines belonging to the first region in the second mode is longer than the period for selecting one scanning line in the first mode. According to this method, in the second mode, the frequency of the scanning line drive signal (scanning signal) and the frequency of the data signal can be decreased.
Further, when the period is set in this way, it is desirable that the selection voltage in the second mode is lower than the selection voltage in the first mode in terms of an absolute value viewed from the center potential. According to this method, the effective voltage values applied to the pixels can be made uniform in the first and second modes.

In the present invention, when the second region is vertically scanned in the second mode, it is preferable that the number of scanning lines simultaneously selected is variable. In the present invention, when the second region is vertically scanned in the second mode, the high-order side holding is performed with respect to two or more scanning lines selected when the second region is vertically scanned. Switching from one of the voltage and the lower holding voltage to the other may be performed at different timings.
The present invention can be conceptualized not only as a driving method of an electro-optical device but also as a driving circuit and an electro-optical device. In addition, since the electronic apparatus according to the present invention includes the electro-optical device as a display unit, power consumption can be reduced.

The best mode for carrying out 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. FIG.
As shown in this figure, the electro-optical device 10 includes an upper circuit 20 and a drive voltage supply circuit 30.
And an electro-optical panel 100.
Among these, the high-order circuit 20 transmits data corresponding to the contents to be displayed, various control signals, etc.
This is supplied to the electro-optical panel 100. Here, as the control signal and the like, in addition to the clock signal and the like, in the present embodiment, as described later, it becomes H level when the display area is vertically scanned, and L level when the non-display area is vertically scanned. There is a signal PD. The drive voltage supply circuit 30 generates a voltage used for a scanning signal and a data signal from a battery or the like (not shown).

The electro-optical panel 100 includes an element substrate formed by extending a plurality of rows of data lines 212 in the column (Y) direction, and a plurality of columns of scanning lines 312 extending in the row (X) direction. The counter substrate is bonded with a certain gap so that the electrode formation surfaces face each other, and a TN (Twisted Nematic) type liquid crystal, for example, is sealed in this gap.
The pixel 116 includes a serial connection of a liquid crystal layer 118 as an example of an electro-optic element and a thin film diode (hereinafter simply referred to as TFD) 220 as an example of a switching element. It is provided corresponding to each crossing part. Here, for convenience of explanation, assuming that the total number of scanning lines 312 is 320 rows and the total number of data lines 212 is 240 columns, the pixels 116 are arranged in a matrix type of 320 vertical rows × 240 horizontal columns.

One end of the TFD 220 is connected to the data line 212, and the other end of the TFD 220 is connected to a rectangular pixel electrode (not shown) provided to face the scanning line 312 that is a stripe electrode.
For this reason, the liquid crystal layer 118 has a configuration in which liquid crystal is sandwiched between both the scanning line 312 as a stripe electrode and a rectangular pixel electrode. In addition, polarizers (not shown) are provided on the non-facing surfaces of both substrates, and the amount of light passing through the liquid crystal layer 118 changes according to the effective voltage value between the electrodes.
On the other hand, the TFD 220 adopts a sandwich structure of conductor / insulator / conductor,
It has a diode switching characteristic in which the voltage characteristic is nonlinear in both positive and negative directions. For this reason, the TFD 220 is in a conductive (on) state when the voltage at both ends thereof is equal to or higher than the threshold value, and is in a non-conductive (off) state when the voltage is lower than the threshold value.

The electro-optical panel 100 has a scanning line driving circuit 350 and a data line driving circuit 250 mounted thereon. Among these, the scanning line driving circuit 350 selects any one of the selection voltages Vp and Vn and the holding voltages Vd and Gnd supplied from the driving voltage supply circuit 30 as will be described later, and the scanning lines in the first to 320th rows. For each of the 312, the scanning signals Y 1 to Y 320 respectively.
As a supply.
Further, the data line driving circuit 250 has a data voltage V supplied from the driving voltage supply circuit 30.
Either d or Gnd is selected as will be described later, and supplied as data signals X1 to X240 to the data lines 212 in the 1st to 240th columns, respectively.
In this embodiment, the data voltages Vd and Gnd are also used as the holding voltage for the scanning signal. However, the data voltage or the holding voltage for the scanning signal may be different from each other.

Next, the display mode of the electro-optical device 10 will be described. The electro-optical device 10 has first and second modes as display modes. Of these, the first mode is shown in FIG.
As shown in a), this is a full screen display mode in which display is performed using all of the pixels 116 corresponding to the scanning lines 312 contributing to display. Note that the scanning lines 312 contributing to the display are intended to eliminate the scanning lines that do not contribute to the display in some cases, because the electro-optical panel 100 may be provided with dummy scanning lines.
On the other hand, the second mode is a partial display mode in which display is performed using only the pixels 116 corresponding to a part of the scanning lines 312 and the other pixels 116 are not contributed to the display. FIG. 2B is an example of the display screen in the second mode, and only the pixels 116 corresponding to the scanning lines 312 in the first to fourth rows and the 318 to 320 rows are display regions.
The pixels 116 corresponding to the scanning lines 312 of the ˜317th row are non-display areas.
In the second mode, the scanning line 312 used as the display area (the scanning line 312 as the non-display area) is arbitrary, but in the following, the case of the screen shown in FIG. 2B will be described as an example. To do.

Next, driving waveforms for the electro-optical panel 100 in this embodiment will be described in the order of the first mode and the second mode. First, FIG. 3 is a diagram showing voltage waveforms of the scanning signal and the data signal in the first mode.
Since the signal PD becomes H level when the display area is vertically scanned as described above, in the first mode in which the pixels corresponding to all the scanning lines 312 are display areas, as shown in FIG. , Always H level.
On the other hand, the scanning line driving circuit 350 has one horizontal scanning period (1F) over one vertical scanning period (1F).
1H), the scanning lines 312 are selected one by one in order from the 1st to 320th rows, and the selection voltage Vp or Vn is applied in the latter half of the selection period, while being held (non-notified) in other periods. Selection) Apply voltage Vd or Gnd.
Here, the non-selection voltages Vd and Gnd are voltages that cause the TFD 220 to become non-conductive regardless of the data voltage supplied to the data line 212 when these voltages are applied to the scanning line 312. Further, the selection voltages Vp and Vn are obtained when this voltage is applied to the scanning line 312.
Regardless of the data voltage supplied to the data line 212, the TFD 220 is in a conductive state. The selection voltages Vp and Vn are the virtual center potential Vc of the data voltages Vd and Gnd.
And the voltage Vp is high and the voltage Vn is low.
In the present embodiment, the polarity of the drive voltage is considered to be positive on the high side and negative on the low side with reference to the center potential Vc, not the ground potential Gnd.

Each voltage of the scanning signals Y1 to Y320 corresponds to the corresponding scanning line 312 in the 1st to 320th rows.
It is determined according to the selected state. Therefore, the scanning signals Y1 to Y320 are generalized by the scanning signal Yi supplied to the scanning line 312 in the i-th row (i is an integer satisfying 1 ≦ i ≦ 320) in FIG. First, the scanning signal Yi is supplied to the i-th scanning line 31.
When the selection voltage Vp is applied in the second half period obtained by dividing one horizontal scanning period (1H) in which 2 is selected, the holding voltage Vd is thereafter held, and secondly, the selection voltage Vp is applied. When the i-th scanning line 312 is selected again after the elapse of one vertical scanning period (1F) from this time, in the second half of the horizontal scanning period, this time, the selection voltage Vn is obtained. The cycle of holding Gnd is repeated.
Further, the scanning signal Y (i + 1) supplied to the scanning line 312 in the (i + 1) th row next to the i-th row.
Takes a selection voltage Vn having a reverse polarity in the latter half of one horizontal scanning period (1H) immediately after the selection voltage Vp is applied as the scanning signal Yi, while 1 immediately after the selection voltage Vn is applied as the scanning signal Yi. In the second half of the horizontal scanning period (1H), a selection voltage Vp having a reverse polarity is taken. That is, in the scanning signals Y1 to Y320, the selection voltages Vp and Vn are alternately selected every horizontal scanning period.

On the other hand, the data line driving circuit 250 has the scanning line 3 selected by the scanning line driving circuit 350.
For one row of pixels 116 corresponding to 12, either data voltage Vd or Gnd is
The data is distributed according to the display content of the pixel and supplied as a data signal via the data line 212.
Here, for the data signals X1 to X240, j from the left in FIG. 1 (j is 1 ≦ j ≦
The data signal supplied to the data line 212 in the column) is expressed as Xj,
This will be described as a representative. In this example, the i-th scanning line 312 is selected,
Assume that the liquid crystal layer 118 is in a normally white mode in which the amount of light passing through is maximized when no voltage is applied.

In this case, the data signal Xj is as follows corresponding to the scanning signal Yi. That is, when the i-th row and j-th column pixel 116 corresponding to the intersection of the selected i-th scan line 312 and the j-th data line 212 is turned off (white display with the highest luminance), i If the scanning signal Yi takes the positive selection voltage Vp in the second half of one horizontal scanning period in which the scanning line 312 of the row is selected, the data signal Xj is transmitted in the first half of the horizontal scanning period (1H). Becomes the lower voltage Gnd, and in the latter half of the period, the higher voltage Vd having the same polarity as the selection voltage
On the other hand, in the second half of the horizontal scanning period in which the i-th scanning line 312 is selected, the scanning signal Yi
Is the negative selection voltage Vn, the data signal Xj becomes the higher voltage Vd in the first half of the horizontal scanning period (1H), and the lower voltage of the same polarity as the selection voltage in the second half Gnd.
When the pixel 116 in the i row and the j column is turned on (black display with the lowest luminance), the scanning signal Yi is a positive selection voltage in the second half of the horizontal scanning period in which the i-th scanning line 312 is selected. V
If p, the data signal Xj becomes a high-side voltage Vd in the first half period of the horizontal scanning period (1H), and becomes a low-side voltage Gnd opposite in polarity to the selection voltage in the second half period. If the scanning signal Yi is the lower selection voltage Vn in the second half of the horizontal scanning period in which the i-th scanning line 312 is selected, the data signal Xj is lower in the first half of the horizontal scanning period (1H). Side voltage Gnd, and in the latter half of the period, it becomes the voltage Vd on the higher polarity side opposite to the selected voltage.
In the case of performing intermediate display between the two, although not particularly illustrated, a period in which a voltage having a polarity opposite to that of the selection voltage is applied in the latter half period in which the selection voltage is applied from white to black. Is set to be long, and in the first half period, the voltage has a polarity opposite to that of the second half period in advance.

When the selection voltage Vp or Vn is applied to the i-th scanning line 312 in the latter half of the selection period, the TFD 220 corresponding to the i-th scanning line 312 is turned on, and the liquid crystal layer 118 has the display contents. While the corresponding voltage is written, the TFD 220 is turned off and the written voltage is held during the other period, that is, the period during which the holding voltage is applied.
When such a writing operation is performed in order for every horizontal scanning period (1H) from the first to the 320th row, a voltage corresponding to the display content is written to all the pixels 116 (liquid crystal layer 118). It will be.

Next, a driving waveform for the electro-optical panel 100 in the second mode will be described. FIG. 4 is a diagram illustrating voltage waveforms of the scanning signal and the data signal in the second mode.
As shown in this figure, in the second mode, the display areas 1st to 4th lines and 318 are displayed.
One horizontal scanning period (1H) in which each of the scanning lines 312 of the ˜320th row is selected is set longer than one horizontal scanning period (see FIG. 3) in the first mode.
First, the scanning lines 312 in the first to fourth rows are selected one row every horizontal scanning period, and one of the selection voltages Vp or Vn is applied in the latter half of the selection period. In the four horizontal scanning periods in which the first to fourth row scanning lines 312 are sequentially selected, the same operation as that in the first mode is performed except that the period is longer.

Next, the scanning lines 312 in the 5th to 317th rows which are non-display areas are selected at once. However, the selection voltage is not applied in the selection period T, and at the center timing of the selection period T, the voltages Vd and Gnd are simultaneously switched from one to the other.
In the second mode, even if a scanning line in the non-display area is selected, the display content of the pixel located on the selected scanning line cannot be considered, so a signal corresponding to OFF display is supplied as a data signal. .
Therefore, if the scanning signals Y5 to Y317 are switched from the holding voltage Gnd to the holding voltage Vd at the center timing of the selection period T, the data signal Xj is the data voltage Gnd.
If the scanning signals Y5 to Y317 are switched from the holding voltage Vd to the holding voltage Gnd at the central timing of the selection period T,
The data signal Xj is switched from the data voltage Vd to the data voltage Gnd.

Thereafter, the scanning lines 312 to 318 to 320 in the display region are selected one row at a time in one horizontal scanning period, and one of the selection voltages Vp or Vn is applied in the latter half of the selection period. In the three horizontal scanning periods sequentially selected for the scanning lines 312 in the 318th to 320th rows, operations common to the first mode are performed except that the period is long.

By the way, in the first mode, when the pixels corresponding to the scanning lines 312 in the 5th to 317th rows are black in the on display, if the mode is suddenly shifted to the second mode, T
Since the FD 220 is not turned on, a direct current component may remain in the liquid crystal layer 118 and the liquid crystal may be deteriorated.
Therefore, when shifting from the first mode to the second mode, it is desirable to perform writing so that at least one vertical scanning period is provided and all the pixels 116 that are to be non-display areas are displayed in an off state.

As shown in FIG. 3, the scanning signals Y5 to Y317 alternately take the holding voltages Vd and Gnd when viewed at the end of one vertical scanning period (1F) in the first mode. On the other hand, as shown in FIG. 4, all of the scanning signals Y5 to Y317 take either one of the holding voltages Vd and Gnd when viewed at the start of one vertical scanning period (1F) in the second mode. State.
For this reason, when the first mode is changed to the second mode, for example, the holding voltage of the scanning signal corresponding to the odd-numbered scanning lines 312 is fixed in the first vertical scanning period in the second mode. Thus, the holding voltage is set to Vd only for the scanning signal corresponding to the even-numbered scanning line 312.
, Gnd may be switched from one to the other.

Here, for comparison with the present embodiment, a conventional driving waveform in the second mode will be described with reference to FIG. As shown in this figure, conventionally, the length of one horizontal scanning period (1H) is common to the first and second modes. Further, in the second mode of the related art, the scanning lines 312 in the non-display area are selected in order for each horizontal scanning period (1H) in the same manner as in the first mode, and the holding voltage is selected from one of Vd and Gnd. Switch to the other.
For this reason, if the pixels in the display area are either on-display or off-display, the number of voltage changes of the data signal Xj in one vertical scanning period does not change in the first and second modes, 320 times equal to the number of scanning lines 312.
On the other hand, in this embodiment, the number of voltage changes of the data signal Xj in one vertical scanning period is 320 times (see FIG. 3) in the first mode and the conventional example (see FIG. 3).
Corresponding to the selection of 12 seven rows and the scanning lines 312 in the non-display area are collectively reduced to 8 times (see FIG. 4). Further, in the present embodiment, since the length of one horizontal scanning period (1H) is set longer than that in the first mode, the data signal X when the scanning lines in the display area are scanned vertically.
The frequency of j also decreases.
While the TFD 220 is off, no voltage is written to the liquid crystal layer 118. However, since the series connection of the TFD 220 and the liquid crystal layer 118 is a kind of capacitive load, power is consumed when the voltage at both ends is switched. Will be. In the present embodiment, the TFD 220 and the liquid crystal layer 1
The number of voltage switching with respect to the series connection with the power supply 18 is drastically reduced, and the frequency of the data signal Xj when the scanning line in the display area is vertically scanned is also reduced. Therefore, it is possible to reduce power consumption as compared with comparative examples.

In the present embodiment, the pixel area corresponding to the scanning lines 312 in the 5th to 317th rows in the second mode is set as a non-display area, but any scanning line 312 to be set as the non-display area is selected. can do. For example, the upper or lower half may be a non-display area. Here, when displaying the upper half pixel area corresponding to the scanning lines in the 1st to 160th rows and not displaying the lower half pixel area corresponding to the scanning lines in the 161st to 320th lines, for example, 1 vertical Scanning period (
1F) is set to 1/161 period as one horizontal scanning period, and each of the scanning lines of the 1st to 160th rows is selected one by one in order. For the selection, one vertical scanning period (1F) ,
A period of 160/161 is required. For this reason, the scanning lines in the 161st to 320th rows may be configured to be collectively selected in the remaining 1/160 period. In this configuration, if the pixels in the display region are either on display or off display, the number of times of voltage switching of the data signal Xj in one vertical scanning period is almost halved from 320 to 161 times. Further, the drive frequency is almost halved.
As described above, as the number of scanning lines 312 to be set as the non-display area in the second mode increases, one horizontal scanning period (1H) in the second mode can be made longer than that in the first mode. At the same time, the number of times of voltage switching of the data signal Xj can be reduced.

By the way, as shown in FIG. 4, when one horizontal scanning period (1H) in the second mode is made longer than that in the first mode, the application period of the selection voltage becomes longer, so one vertical scanning period (1
If the length of F) is the same, the effective voltage value applied to the liquid crystal layer 118 in the first and second modes varies in the direction of increasing. For this reason, when the liquid crystal layer 118 in the display area is turned on, for example, the amount of transmitted light differs between the first mode and the second mode.
Therefore, when one horizontal scanning period (1H) in the second mode is longer than that in the first mode, as shown in FIG. 5, the positive selection voltage Vp is lower than the center potential Vc. In addition, the negative selection voltage Vn may be switched to the higher Vp ′ with respect to the center potential Vc, and the voltage effective values may be substantially the same over the first and second modes.
As described above, as the number of scanning lines 312 to be a non-display area in the second mode increases, one horizontal scanning period (1H) in the second mode can be made longer than that in the first mode. . For this reason, the selection voltage in the second mode may be made closer to the center potential Vc as the number of scanning lines 312 to be a non-display area increases.

In FIG. 4, the scanning signals Y5 to Y317 relating to the non-display area are configured to switch the holding voltage at an intermediate timing of the period T. However, for example, as shown in FIG. Are divided into two groups of Y161 and scanning signals Y162 to Y317,
The holding voltage of the former scanning signals Y5 to Y161 is switched at the preceding timing of the period T, and the holding voltage of the latter scanning signals Y162 to Y327 is then switched at the later timing of the period T. .
Ultimately, as shown in FIG. 7, the holding voltage switching timings of the scanning signals Y5 to Y317 in the period T may be distributed so as not to overlap each other for each scanning line 312.
Thus, even if the holding voltage switching timing applied to the non-display area is distributed in the period T, the number of times of voltage switching of the data signal Xj may be one, so that there is no difference in effect.

In FIG. 4, for all the scanning signals Y5 to Y317 applied to the non-display area, the holding voltage V
Although it is configured to switch from one of d and Gnd to the other in the same direction at the intermediate timing of the period T, for example, as illustrated in FIG. 8, as a configuration in which the holding voltage in the first mode is taken over and switched as it is. Also good.
In this configuration, the liquid crystal layer 11 corresponding to an odd-numbered row among the scanning lines 312 covering the non-display area.
8 and the liquid crystal layer 118 corresponding to the even-numbered rows have different effective voltage values.
Since the FD 220 is in a non-conductive state and is in an off display state, it is not visually recognized as a difference in transmitted light amount.

In the embodiment, one horizontal scanning period (1H) is divided into the first half and the latter half, and the selection voltage is applied in the latter half. However, the horizontal scanning period (1H) may be applied in the first half. The selection voltage may be applied over the horizontal scanning period without dividing the scanning period (1H) into the first half and the second half.
In the electro-optical panel 100 according to the embodiment, 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.

The electro-optical panel 100 is not limited to a transmissive type, and may be a reflective type or a semi-transmissive / semi-reflective type intermediate between the two. In the electro-optical panel 100, the TFD 220 is connected to the data line 21.
2, and the liquid crystal layer 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 liquid crystal layer 118 is connected to the data line 212 side. The structure which is made may be sufficient.
Furthermore, the TFD 220 is an example of a two-terminal switching element. In addition, an element using a ZnO (zinc oxide) varistor, an MSI (Metal Semi-Insulator), or the like, and two of these elements are connected in series in opposite directions. Those connected or connected in parallel can be used as a two-terminal switching element. In the embodiment, a two-terminal switching element such as TFD220 is used as an active element, but in addition to this, a TFT (Thin Film Transi)
A three-terminal switching element such as stor (thin film transistor) can also be used.

In the embodiment, the TN type is used 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 is fixed. A guest-host type liquid crystal in which dye molecules are aligned in parallel with the liquid crystal molecules may be used by dissolving in a molecular alignment liquid crystal (host). 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. As described above, various liquid crystal and alignment methods can be used as long as they are compatible with the driving method of the present invention.
Furthermore, in addition to these liquid crystal devices, it is considered that the present invention can be applied to electro-optical devices such as organic EL (electroluminescence) devices, fluorescent display tubes, electric peristaltic devices, and plasma displays.
The pixel 116 may be arranged corresponding to the primary colors of R (red), G (green), and B (blue), and color display may be performed by expressing one dot with these three pixels. .

Next, an electronic apparatus having the electro-optical device 10 according to the above-described embodiment as a display device will be described. FIG. 9 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 a plurality of operation buttons 1202,
Along with the earpiece 1204 and the mouthpiece 1206, the electro-optical panel 100 described above is provided. In the electro-optical device 10, components other than the electro-optical panel 100 are built in the telephone, so that they do not appear as appearance.
As described above, the electro-optical panel 100 is applied as the display unit of the mobile phone 1200, and the display mode includes a minimum necessary amount such as date, time, radio wave state, battery level, etc. If the information is displayed on or off, it is possible to prolong the callable time and standby time by reducing the power consumed by the electro-optical device.

As an electronic apparatus to which the electro-optical device 10 is applied, the mobile phone 1 shown in FIG.
In addition to the 200, a digital still camera, a notebook computer, an LCD TV, a viewfinder type (or monitor direct view type) video recorder, a car navigation device, a pager,
Examples include electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, and devices equipped with touch panels. Needless to say, the electro-optical device 10 described above can be applied as a display device of these various electronic devices. And in any electronic device, it becomes possible to suppress the electric power consumed low.

1 is a block diagram illustrating a configuration of an electro-optical device according to an embodiment of the invention. FIG. It is a figure which shows the display mode by the electro-optical device. FIG. 6 is a diagram illustrating a drive waveform in a first mode of the electro-optical device. It is a figure which shows the drive waveform in the 2nd mode of the same electro-optical apparatus. FIG. 10 is a diagram illustrating another drive waveform in the second mode of the electro-optical device. FIG. 10 is a diagram illustrating another drive waveform in the second mode of the electro-optical device. FIG. 10 is a diagram illustrating another drive waveform in the second mode of the electro-optical device. FIG. 10 is a diagram illustrating another drive waveform in the second mode of the electro-optical device. It is a figure which shows an example of the mobile phone to which the same electro-optical device is applied. It is a figure which shows the drive waveform in the 2nd mode of the conventional electro-optical apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electro-optical apparatus, 20 ... High-order circuit, 30 ... Drive voltage supply circuit, 100 ... Electro-optical panel, 116 ... Pixel, 212 ... Data line, 250 ... Data line drive circuit, 312 ... Scan line,
350: Scanning line driving circuit, 1200 ... Mobile phone

Claims (10)

A pixel provided corresponding to each intersection of a plurality of scanning lines and a plurality of data lines, each including a switching element and an electro-optical element, and when the switching element becomes conductive, the electrical A method for driving an electro-optical device, in which an optical element has a pixel having gradation according to a data signal supplied to at least a data line,
A first mode in which pixels corresponding to all the scanning lines contributing to display are in a display state; and a first area composed of pixels corresponding to some of the plurality of scanning lines is in a display state. On the other hand, having a second mode in which the second region consisting of pixels corresponding to the remaining scanning lines is not displayed,
When in the first mode and when vertically scanning the first region in the second mode,
A scanning line is selected row by row, and a selection voltage is applied to the selected scanning line to make the switching element conductive.
For data lines
A data signal is supplied according to the gradation of the pixel corresponding to the intersection of the selected scanning line and the data line,
When vertically scanning the second region in the second mode,
An electro-optical device characterized by selecting two or more rows of scanning lines belonging to the second region and applying a holding signal for making the switching element non-conductive to each of the selected scanning lines. Driving method. The data signal takes either a high-order data voltage or a low-order data voltage that is symmetrical with respect to a predetermined center potential,
The selection voltage includes
There are a high-side selection voltage and a low-side selection voltage that are symmetrical with respect to the center potential,
When in the first mode and when vertically scanning the first region in the second mode,
Apply one of the selection voltages to the selected scan line,
For data lines
The polarity of the selection voltage applied to the selected scanning line according to the gray level of the pixel corresponding to the intersection of the selected scanning line and the data line, as the data signal, the high side data voltage and the low side data voltage To distribute and supply according to
When vertically scanning the second region in the second mode,
The method of driving an electro-optical device according to claim 1, wherein the data signal is supplied by switching from one of the high-order data voltage and the low-order data voltage to the other. The data signal takes either a high-order data voltage or a low-order data voltage that is symmetrical with respect to a predetermined center potential,
The selection voltage includes
There are a high-side selection voltage and a low-side selection voltage that are symmetrical with respect to the center potential,
The holding voltage includes
There are a high-side holding voltage and a low-side holding voltage that are symmetrical with respect to the center potential,
When in the first mode and when vertically scanning the first region in the second mode,
One selected voltage is applied to the selected scanning line in one period obtained by dividing one horizontal scanning period into two, and one holding voltage is applied in the other period obtained by dividing one horizontal scanning period into two. ,
For data lines
In one period obtained by dividing one horizontal scanning period into two, the high-side data voltage and the low-side data voltage are set according to the gradation of the pixel corresponding to the intersection of the selected scanning line and the data line.
Distribute and supply according to the polarity of the selection voltage applied to the selected scan line,
In the other period obtained by dividing one horizontal scanning period into two,
Apply a low-side data voltage for approximately the same period as the high-side data voltage is applied during one period, and apply a high-side data voltage for a period approximately synchronized with the low-side data voltage applied during one period. ,
When vertically scanning the second region in the second mode,
Supplying the selected scanning line by switching from one of the high-side holding voltage or the low-side holding voltage to the other,
The method of driving an electro-optical device according to claim 1, wherein the data signal is supplied by switching from one of the high-order data voltage and the low-order data voltage to the other. A period for selecting a scanning line belonging to the first region in the second mode,
4. The driving method of the electro-optical device according to claim 1, wherein the driving period is longer than a period for selecting one scanning line in the first mode. 5. The selection voltage in the second mode is an absolute value viewed from the center potential, and the first voltage
The driving method of the electro-optical device according to claim 4, wherein the selection voltage is lower than the selection voltage in the mode. When vertically scanning the second region in the second mode,
The driving method of the electro-optical device according to claim 1, wherein the number of scanning lines simultaneously selected is variable. When vertically scanning the second region in the second mode,
For two or more scanning lines selected when the second region is vertically scanned,
The method of driving an electro-optical device according to claim 3, wherein switching from one of the high-side holding voltage and the low-side holding voltage to the other is performed at different timings. A pixel provided corresponding to each intersection of a plurality of scanning lines and a plurality of data lines, each including a switching element and an electro-optical element, and when the switching element becomes conductive, the electrical A drive circuit of an electro-optical device having a pixel whose optical element has a gradation corresponding to at least a data signal supplied to a data line,
A first mode in which pixels corresponding to all the scanning lines contributing to display are in a display state; and a first area composed of pixels corresponding to some of the plurality of scanning lines is in a display state. On the other hand, having a second mode in which the second region consisting of pixels corresponding to the remaining scanning lines is not displayed,
When in the first mode and when vertically scanning the first region in the second mode,
While selecting a scanning line row by row and applying a selection voltage for bringing the switching element into a conductive state with respect to the selected scanning line,
When vertically scanning the second region in the second mode,
A scanning line driving circuit for selecting two or more rows of scanning lines belonging to the second region and applying a holding signal for making the switching element non-conductive to each of the selected scanning lines;
When in the first mode and when vertically scanning the first region in the second mode,
For data lines
A drive circuit for an electro-optical device, comprising: a data line drive circuit that supplies a data signal in accordance with a gradation of a pixel corresponding to an intersection of a selected scanning line and the data line. A pixel provided corresponding to each intersection of a plurality of scanning lines and a plurality of data lines, each including a switching element and an electro-optical element, and when the switching element becomes conductive, the electrical A pixel whose optical element has a gradation corresponding to at least a data signal supplied to the data line;
A first mode in which pixels corresponding to all the scanning lines contributing to display are in a display state; and a first area composed of pixels corresponding to some of the plurality of scanning lines is in a display state. On the other hand, having a second mode in which the second region consisting of pixels corresponding to the remaining scanning lines is not displayed,
When in the first mode and when vertically scanning the first region in the second mode,
While selecting a scanning line row by row and applying a selection voltage for bringing the switching element into a conductive state with respect to the selected scanning line,
When vertically scanning the second region in the second mode,
A scanning line driving circuit for selecting two or more rows of scanning lines belonging to the second region and applying a holding signal for making the switching element non-conductive to each of the selected scanning lines;
When in the first mode and when vertically scanning the first region in the second mode,
For data lines
An electro-optical device, comprising: a data line driving circuit that supplies a data signal in accordance with a gradation of a pixel corresponding to an intersection of a selected scanning line and the data line.   An electronic apparatus comprising the electro-optical device according to claim 9.

Images