JPH02823A - Driving method for liquid crystal element - Google Patents

Abstract

PURPOSE:To make a stable gradational display on ferroelectric liquid crystal by multiplex-driving by applying a specific alternating current whose pulse width is less than a half as wide as that of a pulse in a nonselection period. CONSTITUTION:An electric field which puts liquid crystal molecules in a 1st state and a correcting electric field which eliminates the one-sided state of charges in the whole waveform are applied from the rear part of the nonselection period to the front part of a selection period and electric fields which correspond to a saturation voltage and a threshold voltage are applied in the rear part of the selection period at a ratio corresponding to gradation data so as to put the liquid crystal layer in a 2nd state. Then the pulse width is less than a half as wide as that of select pulses in the nonselection period and the alternating current where (wave height valueXpulse width) is less than (threshold valueXpulse width of selective pulse) is applied. The whole driving waveform goes to a complete alternating current to eliminate the one-sided state of charges between upper and lower substrates. Consequently, the stable gradational multiplex-driving is enabled.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a liquid crystal device, and more particularly to a multiplex driving method for a device using ferroelectric liquid crystal. [Prior art] As a conventional driving method for displaying gradation of a liquid crystal element,
There is a method of driving TN liquid crystal using pulse modulation. As shown in FIG. 5, this method operates by applying a signal such as 501 to the scanning electrode and a signal such as 502 to the signal electrode. In addition to this method,
There is a method of driving a ferroelectric liquid crystal by pulse width modulation, as disclosed in Japanese Patent Application No. 60-243313. As shown in FIG. 6, this method applies a signal such as 601 to the scan it pole,
It operates by applying a signal such as 602 to a signal electrode.

[Problem to be solved by the invention 1 In the case of the above drive 1 Is there a signal depending on the display content? I
! If the voltage of the signal applied to the pole is biased towards the positive side,
If such a driving method is used with a ferroelectric liquid crystal device, which may bias toward the negative side, the applied waveform will be If the charge is not neutralized throughout, the charge will be biased in the opposite direction of the upper and lower bases during driving, resulting in loss of memory properties and unstable gradation. The memory property referred to here refers to the effect that the gradation state selected in the selection period remains even when not selected. Also, since the signal type i signal is applied during the non-selected period, the liquid crystal molecules The liquid crystal element of the present invention is driven by at least a scanning method.
Driving force i of a liquid crystal element in which a ferroelectric liquid crystal is sandwiched between a substrate on which poles are formed and a substrate on which signal electrodes are formed. (1) From the rear of the non-selection period to the front of the selection period, an electric field in which the liquid crystal molecules take the first state and a correction electric field to eliminate the unbalanced charge of the waveform as a whole are applied, and at the rear of the selection period, A saturation voltage to bring the liquid crystal layer into the second state and an electric field corresponding to the threshold voltage are applied at a ratio corresponding to the gradation data, and during the non-selection period, the pulse width is less than half of the selected 1-scale pulse. It is characterized in that an alternating current is applied where (peak value x pulse duration) is smaller than (threshold value x selection pulse duration). (2) During the non-selection period, the scanning line is placed in a high impedance state of 100Ω or more with respect to the scanning electrode signal line, and after the non-selection period, it is again brought into a low impedance state of 100Ω or less, specifically, 100Ω or less. Features. (3) From the rear of the non-selected 1st river to the front of the selection period, if the selection period is divided into three, this is the first pulse, and if it is divided into two, the pulse inserted before the selection period is used to reduce the charge of the selection signal. It is characterized by applying an electric field that makes the total sum zero, and when one selection period is divided into three, the second pulse is applied, and when it is divided into two, the electric field is applied so that the liquid crystal layer takes the first state with the first pulse. shall be. (4) i1 from the end of the non-selection period! 8 in front of the selection room, i1! In front of Sawahoma, a piece of charge j: f as the whole waveform
An electric field is applied to bring the liquid crystal molecules into the first state, and 2
The present invention is characterized in that an electric field is applied to the first half of the divided selection period to cancel the electric field applied during the second half of the selection period. 1 Effect l According to the above driving method, the entire driving waveform becomes a complete alternating current, and the unevenness of electric charge between the upper and lower substrates due to driving is eliminated. In addition, the pulse width of all grayscale signals during the non-selection period is half the width of the selected tR pulse. The liquid crystal is extremely difficult to respond to this signal because it is under low light. Therefore, by using the driving method of the present invention, extremely stable gradation multiplex driving can be performed. Also, if the scanning line is placed in a high impedance state with respect to the scanning TLti signal line during the non-selection period, the liquid crystal will be in this! . . . The response becomes even more difficult between the two, thereby making it possible to perform more stable gradation multiplex driving. [Example] Examples 1 to 4 are examples of the driving method of (3) above. Embodiment 1 Hereinafter, embodiments of the present invention will be described in detail.For convenience, this embodiment is designed to display eight gradations. Furthermore, a case where a pulse with a negative polarity and a voltage higher than the saturation voltage is applied is defined as a dark state, and a case where a pulse with a positive polarity and a voltage higher than the saturation voltage is applied is defined as a bright state. Here, a case will be described in which a correction pulse is applied before the selection period. It goes without saying that the six circuit configurations shown in FIG. 1 as an example of the drive circuit do not necessarily have to be as shown, and any circuit configuration may be used as long as the composite waveform 351 shown in FIG. 3 can be obtained. In FIG. 1, reference numeral 101 is a selection pulse cut-off signal, which switches the transmission gate 121. As a result, a waveform as shown in the timing chart 211 of FIG. 2 is applied to the drive potential signal line 111. 102 is gradation data, 8I! I! In response to Makoto, a 3-bit groove structure is used here. This data is transferred to the signal electrode side shift register 161 by the shift clock 103, and when the data transfer for 942 scans is completed, it is latched into the latch part 162 by the latch signal 104, and the output of this latch is sent to the decoder part 163. It is decoded to make the opening/closing period of the transmission gate 124 correspond to the gradation data. As a result 5, for example, the waveform shown at 342 in FIG.
is applied to FIG. 11(a) shows how the gradation data corresponds to the opening/closing period of the transmission gate 124 at this time. The opening and closing of the transmission gate may be reversed for gradation data 1, however, in this case, black and white are reversed. For the scanning electrode side, input the selection pulse switching signal lO1 into the counter and shift register. Four selection pulse switching signals are taken out and the transmission gate 122 is switched accordingly. As a result, the waveform shown in the timing chart 219 of FIG. 2 is applied to the drive potential signal II 119. Shift the scanning signal data 105 in FIG.
Scan electrode 111+1 shift register 17 by 06
1, the scanning electrodes are selected line by line. Thereafter, a waveform to which a correction pulse has been added by the transmission gate is output. FIG. 3 is 341. As described above, waveforms as shown in FIG. 3 341 and 342 are applied to the scanning electrode 141 and the signal electrode 142, respectively. Therefore, the pixel 151 at the intersection of both 11Wt4 has a third
A waveform as shown in FIG. 351 is applied. In Figure 3, the horizontal direction is the time axis -1+, tz, t
Both s and js are selection periods, and each is divided into two (1
+, it is divided into t++, t+i). Also, t...
js and ty are the non-selection period before the 0 selection period, that is, the latter half of the non-selection period is the charge correction pulse application period. During this period. A voltage of Pws is applied for Pws seconds. Pws can be changed arbitrarily by changing one circuit. The first half of the selection period is an erase pulse application period. This +111 field has negative polarity and an electric field of at least Ivt1 or more is applied to the liquid crystal layer. The optical response of the ferroelectric liquid crystal element to the applied voltage is shown in FIG. 4. In FIG. 4, the horizontal axis is the applied voltage and the vertical axis is the optical transmittance. Now, if the absolute value of the erase pulse V8 is greater than the absolute value of Vsat2 in FIG. 4, the liquid crystal layer will be in a dark state regardless of the state before the application of the electric field. Next, in the latter half of the selection period, one or both of VI and Vl +vs with positive polarity and peak value are applied. At this time, the wave height value V1 is the same as Vtl+1 in Fig. 4, and V
, +V, are the same as V5atl in FIG. 4, the state of the liquid crystal layer becomes an intermediate state between the dark state and the bright state according to the ratio of the pulse with the peak value vl and the pulse with the peak value v, +■. v
If the pulse application time of l is long, the halftone becomes close to a dark state, and if the pulse application time of v1+Vs is long, a halftone becomes close to a bright state. When the selection period ends, it becomes a non-selection period. In Figure 3, t
It is between 1171 such as s, ts, and t7. During these periods, electric fields in various pulses are applied to the liquid crystal layer, but in each case, the absolute value of the voltage is Ivsl"c'. Therefore, 1Vsl is expressed as Fig. 4 (7) IVtl+l l and 1V
If it is set smaller than th21, the halftone state written during one selection period will not change, and since the pulse during this period is less than half of the selection pulse, a very stable display state will be achieved. As a result of applying these waveforms, the optical response of the liquid crystal layer becomes as shown in FIG. 3 302. The vertical axis of 302 is transmittance. In this way, gradation display became possible. Here, the conditions for setting the applied voltage for performing such driving will be summarized and shown again. Vs l > l Vsat2 V, l < IV thll Va 1 < IV th21 Vs I < l V thll V + + V s l > l Vsatl 1
As can be seen from the above description, the present invention is not limited to eight gradations, but is possible with any number of gradations. Further, the polarity of the applied voltage and the polarity of the optical response can be arbitrarily set depending on the positional relationship between the polarizing plate and the liquid crystal element. The reason why halftone states can be displayed is that a certain part of the liquid crystal layer to which a signal corresponding to a certain halftone is applied is in the first state, and the remaining part is in the second state. This is because all of the states are stable with respect to the electric field applied between the non-selected rivers. and the first state part and the second state part
This is because the area ratio of the state portion can be arbitrarily changed by the method shown in this embodiment. In this example, ? IllI positive pulse pulse [
You can choose 11 relatively freely. This is because the correction pulse is always outside the non-selection period. Therefore, by widening the pulse of the correction pulse, the voltage can be lowered accordingly, and vice versa. Example 2 Here, in Example 1, i1! An example in which the erase pulse and write pulse during the selection period have shapes as shown in FIG. 2 will be described. The location of the circuit changes in this case will be described. (2) The signal 101 is input to the transmission gate 121 of (2) through the inverter.The signal 101 is input to the transmission gate 121 of Vs. V+ +
The input signals of the transmission gates of V3 and V are reversed. Reverse the input signals of the transmission gates of V, -V, and V. By doing this, the waveform shown in FIG. 2 219' becomes the drive potential signal! ! I! 119, 211'
The waveform is output to the drive potential line 13. Waveform 2
! 9' is the waveform applied to the scanning electrode 141 via the shift register 171 and the transmission gate 123, compared to 341 in FIG. The opposite is true. Waveform 211″ is signal electrode side shift register 1
61, latch portion 162. The waveform applied to the 0 pixel 151 modulated during the pulse by the decoder section 163 and applied to the scanning electrode 142 through the transmission gate 124 is shown in FIG. 7 701. The optical response to this waveform was the same as in Example 1. Embodiment 3 Here, an example will be described in which the shape of the erase pulse and write pulse in the selection period is 21N229 in Embodiment 1. A 2-pulse frequency divider circuit is inserted after the 0 selection pulse switching signal 101 that describes the location of the circuit change at this time, and its output is manually input to the transmission gate 121. −
The transmission gate 121 of V is connected to an inverter. Pulse width modulation is applied to the waveform 221 output to the drive potential line ill according to the gradation data.
FIG. 11(b) shows the gradation data and the opening/closing of the transmission gate 124! The correspondence between the opening and closing periods of the transmission gates up to 68 may be completely reversed. However, in that case, the brightness and darkness will be completely reversed. Regarding the scanning electrode side. Swap the input signals of the transmission gates v, V, -V. That's all you need. The waveform applied to the pixel 151 in this case is shown in FIG. 7 702. The optical response to this waveform was the same as in Example 1. Embodiment 4 Here, an example will be described in which the shape of the erase pulse and write pulse in the selection period in Embodiment 1 is as shown in FIG. 229. The location of the circuit changes in this case will be described. This is basically the same as the implementation 1913, but an inverter is inserted before the 2-pulse frequency divider circuit. V in Figure 3, and V+ +V*
Reverse the input of the inverter. The correspondence between the 0 gradation data and the opening/closing timing of the transmission gate 124, which is all that is required, is the same as in the third embodiment. The waveform applied to the pixel 151 in this case is shown in FIG. 7 703. The optical response to this waveform was the same as in Example 1. Embodiment 5 Here, an embodiment in which a correction pulse is applied in the first half of the selection period will be described. FIG. 8 shows an example of the drive circuit. The configuration of the 0 circuit ti shown in FIG. 108 is a data polarity switching signal, which has a waveform 908 in FIG. This switches the transmission game 1-121. As a result, the waveform shown in FIG. 9 911 is outputted to the drive potential signal line 111, which is then modulated during pulses in accordance with the gradation data. The modulation method in that case is as shown in the first embodiment. However, the point y is that Ov is output to the signal electrode 142 during the correction pulse application period. In this way, a waveform 1042 in FIG. 10 is obtained. On the scanning electrode side, the shift clock 107 (waveform 907 in FIG. 9) is used to obtain five outputs with different phases using the shift clock 18], and these outputs are Vs, Vt, Vs-V.
s, V+ +Vs, Vl (7) The transmission gate 122 is scanned to obtain a waveform 919 in FIG. This is scanned by the scanning electrode shift register 171, and the first
A waveform of 1041 is applied to the scanning electrode 141. As a result of the above, a composite waveform 1051 in FIG. 10 is applied to one pixel 151. In FIG. 10, the horizontal direction is the time axis. 1;+, j*, f, x, and jn are all selection periods, and each is divided into three divisions (1+ in the case of 1+, 1 st. t +s). Further, tl, ts, f, and t are non-selection periods, and the first half of the 0 selection period is a charge correction pulse application period. During this period, the polarity is positive and Vs = lv, l
A voltage v of −1vtl is applied. The middle of the selection period is the erase pulse application period. During this period, a negative electric field of at least +V, + or more is applied to the liquid crystal layer. In the second half of the selection period, the peak value is Vl or V with positive polarity.
One or both of ++Vm is applied. When the selection period ends, there is a non-selection period. In FIG. 10, the periods are js, js, tv, etc. During this period, an alternating current having a pulse length less than half of the selection pulse is applied, and the voltage V is IVsa
Because tll and IVsat are below 21. The display becomes very stable. As a result of applying these waveforms, the optical response of the liquid crystal layer becomes 1002 in FIG. In this way, gradation display became possible. Here, the conditions for setting the applied voltage for performing such driving are almost the same as in the first embodiment. Regarding Vs. Vs = lVx l-1v. The points not described in detail in this embodiment are the same as in the first embodiment. Embodiment 2. Implementation +9113
, - The same driving method as in Example 4 is possible, and the optical characteristics in this case are the same as those in this example. This example is an example! , Example 2. Since one selection period is 372 times longer than that in the third embodiment, the scanning time is also 3/2 (2).Next, the sixth to ninth embodiments are examples of the driving method described in (4) above. Embodiment 6 The circuit configuration shown in FIG. 12, which shows an example of the drive circuit, does not necessarily have to be this way; any circuit configuration can be used as long as the composite waveform 1451 shown in FIG. 14 is obtained. Needless to say, in FIG. 12, lot is a polarity switching signal, which switches the transmission gate 1-121.As a result, the drive potential signal ll111 has the timing chart 13 in FIG.
A waveform as shown in 11 is applied. Reference numeral 102 indicates gradation data, which here has a 3-bit configuration corresponding to 8 gradations. This data is transferred to the signal iti side shift register 161 by the shift clock 103, and
When the data transfer for the scanning line is completed, the data is latched into the latch section 162 by the latch signal 104, and the output of this latch is decoded by the decoder section 163 to make the opening/closing period of the transmission gate 124 correspond to the gradation data. As a result 1, for example, the waveform shown at 1442 in FIG. 14 is transmitted to the signal electrode 1 through the signal waveform transmission line 132 in FIG.
42. The first method is to make the gradation data correspond to the opening/closing period of the transmission gate 124 at this time.
The opening and closing method of the transmission gate may be reversed for the 0 gradation deck l shown in FIG. 6(a), however, in this case, black and white are reversed. On the scanning electrode side, the selection pulse switching signal 108 is input to the counter and shift register 181, and four selection pulse switching signals are taken out. This switches the transmission gate 122. As a result, the timing chart shown in FIG. 13 is displayed on the drive potential signal line 119. A waveform shown at 319 is applied. By transferring the scan signal data 105 shown in FIG. 2 to the scan electrode side shift register 171 by the shift lock 106, the scan 1! The poles are selected line by line, and then the transmission gate outputs a waveform to which a complete alternating current erase pulse is added. It is 1441 in FIG. As described above, the waveforms 1441 and 1442 in FIG. 14 are applied to the scanning electrode 141 and the signal electrode 142, respectively. Therefore, the pixel 151 at the intersection of both mti has the first
A waveform as shown in FIG. 4 1451 is applied. In FIG. 14, the horizontal direction is the time axis. j+, l+ ts, and tn are all between selection 1ul1, and each is divided into two (for 1+, t ll+ t +i)
It can be divided into Further, ts, j@+tt is a non-selection period before the 0 selection period, that is, the last part of the non-selection period is between the complete AC erase pulse applicators. During this period, a complete AC erasing pulse with a peak value of ±V is applied.The optical response of the ferroelectric liquid crystal element to the applied voltage is shown in Fig. 4.The horizontal axis of Fig. 4 is the applied voltage; The vertical axis is optical transmittance. Now, the absolute value of the erase pulse Vs is V in FIG.
If it is larger than the absolute value of aat2, the liquid crystal layer will be in a dark state regardless of the state before the application of the electric field. Next, in the latter half of the selection period, one or both of Vl, V, and +Vs with positive polarity and peak value is applied. At this time, the wave height value V is the same as Vt111 in Fig. 4, and Vl
If +V3 is the same as the fourth section V5atl, the state of the liquid crystal layer becomes an intermediate state between the dark state and the bright state according to the ratio of the pulse with the peak value V and the pulse with the peak value Vl+V3. If the Vl pulse is applied for a long time, the gray level becomes close to a dark state, and ■. If the pulse application time of +v is long, an intermediate tone close to a bright state will be obtained. When the selection period ends, it becomes a non-selection period. In Figure 14, ta, ja, ty, etc.! It is between Il1. During these periods, various pulsed electric fields are applied to the liquid crystal layer;
In either case, the absolute value of the voltage is lVl 11',
Figure 4 (7) l Vtl+1 1 F-I Vth2
The relationship with 1. IVs lXPw<1Vthl Ixt+tI V
s l ×P W < l V th2 I X t
+ If it is il! The intermediate state written during the selection period does not change, where Pw is 0 in the pulse applied during the non-selection period. In a normal liquid crystal, v, I is 1v, 1 or less, and Pw is less than 1. Since it is less than half of t, a very stable display state is achieved. As a result of applying these waveforms, the optical response of the liquid crystal layer is as shown in Fig. 14.
It becomes 402. The vertical axis of 1402 is transmittance. In this way, gradation display became possible. Here, the conditions for setting the applied voltage for performing such driving will be summarized and shown again. I V, I > I Vsat21 1V, I<IVthl 1 IVs IXPw<I'Vth21Xt+tl Vs
I X Pw< l Vtl+I I X t++
, I V+ +Vs l > l Vsatl1 As can be seen from the above explanation, the present invention is not limited to eight gradations, but is possible with any number of gradations. Further, the extreme pressure of the applied voltage and the extreme pressure of the optical response can be arbitrarily set depending on the polarization 1 and the 1y positional relationship of the liquid crystal element. The reason why halftone states can be displayed is that a certain part of the liquid crystal layer to which a signal corresponding to a certain halftone is applied is in the first state, and the remaining part is in the second state. This is because all of the states are stable with respect to the electric field applied during the non-selection period. This is because the surface Fffl ratio between the first state portion and the second state portion can be changed arbitrarily by the method shown in this embodiment. In this embodiment, the pulse of the complete alternating current erase pulse can be selected relatively freely. This is because the erase pulse is always outside the non-selection period. Therefore, it is possible to widen the erase pulse and lower the voltage accordingly, and vice versa. Embodiment 7 Here, an example will be described in which the shape of the erase pulse and write pulse for one selection period in Embodiment 6 is 1319'' in FIG. A signal of 101 is input to the -Vs transmission gate 121.V+
Reverse the input signals of the transmission gates +V3 and ■. -V+ The input signals of the transmission gate 122 of -Vs and -Vl are reversed. By doing this, the waveform of 1319° in FIG.
9, +311' is the drive potential signal M
Output to ill. Waveform 1319'' is the scanning electrode shift register 171 and transmission gate 123.
The waveform applied to the scanning electrode 141 through
Compared to 41, the -vI and -Vt-Vs pulses are reversed. The pulses of V++Vs and V are reversed. Waveform 13
11' is a signal electrode side shift register 161, a latch section 162. The waveform applied to the 0 pixel 151 modulated during the pulse by the decoder section 163 and applied to the scanning electrode 142 through the transmission gate 124 is shown in FIG.
It is. The optical response to this waveform was the same as in Example 6. Example 8 Selected here in Example 6! (An example will be described in which the shape of the erase pulse and write pulse between 8 and 8 is as shown in FIG.
In the figure, a 2-pulse frequency divider circuit is inserted after the polarity switching signal 101, and its output is sent to the transmission gate 12.
Enter 1. Impark is applied to the transmission gate 121 of ``-Vs. Pulse width modulation is applied to the waveform 221 outputted to the drive potential !31111 according to the gradation data. 0 indicating how to correspond between data and the opening/closing period of the transmission gate 124
It is also possible to completely reverse the correspondence between the opening and closing periods of the transmission gates for gradation scales 1 and 8. However, in that case, the brightness and darkness will be completely reversed in the 0th order scan 1tiIi
As for the side, input the transmission gate input signals of -Vl, -V, and -V. That's all you need. The waveform applied to the pixel 151 in this case is shown in FIG.
The optical response to this waveform, shown in Figure 1, was the same as in Example 6. Embodiment 9 Here, an example will be described in which the erase pulse and write pulse for selective opening and opening in Embodiment 6 have shapes as shown in FIG. 13, 1329'. The location of the circuit changes in this case will be described. This is basically the same as the eighth embodiment, but an inverter is inserted before the two-pulse frequency divider circuit. V in Figure 14, and V++Va
The correspondence between the 0 gradation data for reversing the input of the inverter and the opening/closing time of the transmission gate 124 is the same as in the eighth embodiment. The waveform applied to the pixel 151 in this case is shown in FIG. 15 1503. The optical response to this waveform was the same as in Example 6. Next, an example of the driving method described in (2) above will be described. Embodiment 1O In this embodiment, scanning N after the selection period ends in Embodiment 1.
FIG. 17 shows a basic circuit diagram of this embodiment, showing an example of putting the pole in a high impedance state with respect to the scanning electrode signal line. Regarding the contents of the scanning electrode driver 1703 and the signal electrode driver 1708 in FIG. was based on Example 1. The switch 1710 connects the scanning voltage ti 1712 and the scanning Ml pole driver 1707 during the selection period, and during the non-selection period]
via 709. The timing at which the switch 1710 is connected through the resistor may be any time during the non-selection period, but it is preferable to do so immediately after the selective opening as much as possible.Here, IKΩ was used as the resistor. As a result, although it depends on the display content, the amplitude of the signal applied to the pixel during the non-selection period was almost negligible, and the liquid crystal molecules hardly swayed, so the contrast and memory performance were also good. For example, in the case of an element using Chisso C5-1015 for the liquid crystal and polyimide for the alignment film, the contrast was 1=8 in Example 1, but in this example, the contrast was 1.
: It became 11. This example can be applied not only to Example 1 but also to Examples 2 to 9.

【Effect of the invention】

The present invention has made it possible to stably display gradations using multiplex drive of a ferroelectric liquid crystal.1 The present invention is a method for realizing so-called wall-mounted televisions and wall-mounted displays using ferroelectric liquid crystals. This is the result.

[Brief explanation of the drawing]

FIG. 1 is a drive circuit diagram of Embodiment 1 of the present invention. FIG. 2 shows Example 1. Example 2. Example 3. Implementation 19q4
FIG. 4 is a timing chart diagram of drive potential signal lines depending on the timing. FIG. 3 is a drive waveform timing chart diagram in the first embodiment. FIG. 4 is a diagram showing a voltage-transmittance curve of a ferroelectric liquid crystal element. Figure 5 shows lIi,,l! of a conventional TN type liquid crystal. J drive waveform diagram. Figure 16 is an improved driving waveform diagram of a conventional ferroelectric liquid crystal. FIG. 7 shows examples 2 and 3. FIG. 7 is a diagram of a composite waveform applied to a pixel 151 in Example 4. FIG. The peak value of each waveform is based on FIG. 3. FIG. 8 is a drive circuit diagram in Example 5G. FIG. 9 is a timing chart diagram of the drive potential signal line in the fifth embodiment. FIG. 10 is a drive waveform timing chart in Example 5. FIG. 11 is a diagram showing the correspondence between gradation data and the opening/closing period of the transmission gate. FIG. 11(a) is a diagram corresponding to the first embodiment. FIG. 11(b) is a corresponding diagram of the third embodiment. FIG. 12 is a drive circuit diagram of Embodiment 6 of the present invention. FIG. 13 shows Example 6. Example 7. Example 8. 9 is a timing chart diagram of drive potential signal lines in Example 9. FIG. FIG. 14 is a drive waveform timing chart diagram in Example 6. FIG. 15 shows Example 7 and Example 8. FIG. 9 is a diagram of a composite waveform applied to a pixel 151 in Example 9. The peak value of each waveform is shown in FIG. FIG. 16 is a diagram showing the correspondence between gradation data and the opening/closing period of the transmission gate. FIG. 16(a) is a diagram corresponding to the sixth embodiment. FIG. 16(b) is a corresponding diagram of the eighth embodiment. FIG. 17 is a diagram of the fh driving circuit of Example 110. 101 ・ ・ 102 ・ ・ 103 ・ ・ 104 ・ ・ 105 ・ ・ 106 ・ ・ 107 ・ ・ 10B ・ 111.1 121, 1 131 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 104 ・ ・ 105 ・ ・ 106 ・ ・ 107 ・ ・ 10B ・ 111.1 121, 1 131 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 102 ・ ・ 103 ・ ・ 104 ・ ・ 105 ・ ・ 106 ・ ・ 107 ・ ・ 10B ・ 111.1 121, 1 131 ・ ・ ・ ・ ・ Polarity switching signal ・ ・ Gradation data ・ ・ Gradation data shift clock Ivy...Latch signal...Scanning signal Data...Scanning signal Shift clock...Shift clock signal...Selection pulse cut I attack signal 15.119...Drive potential signal line 22.123.124...Transmission gate...Scanning Waveform transmission line 132, 141, 142, 161, 162, 163, 181, 182, 219.111 ・ ・ 219 ゛ 211 '229 ・ ・ ・ Signal waveform transmission line ・ Running TRI pole, signal I pole・Pixel/Part of signal electrode side shift register ・Latch section ・Decoder section ・Scanning electrode shift register ・Selection pulse shift register ・2-pulse frequency divider circuit ・Advance selection pulse cut 12ILt waveform ・Scanning electrode selection tJ in Example 1? Signal waveform...Signal electrode selection No. 13 waveform in Example 1...Scan electrode selection 117 signal waveform in Example 2...Signal electrode selection signal waveform in Example 2...Scan electrode selection in () in Example 3 221 ・ 229 '・ 221 ・ ・ ・ ・ 信 信 信 信 信 信 信 信 信 信 信 信 信 信 信 信Electrode selection signal waveform...Scanning electrode selection signal waveform according to Example 4...Signal electrode selection signal waveform in Example 4・Scan m pole waveform・Signal electrode waveform・Synthetic waveform of 341 and 342・Pixel transmittance Change - Positive threshold voltage - Positive saturation voltage - Negative threshold voltage - Negative saturation voltage - Scan electrode waveform - Signal 1! Positive waveform, combined waveform of 501 and 502, scanning electrode waveform, signal m-pole waveform 603 ・ 701 ・ 702 ・ 703 ・ 907 ・ 908 ・ 919 ・ 911 ・ +041 ・ +042 ・ 051 ・ 1002 ・ 1301 ・ l 319 ・ 13 l ! - +319' +31 1' - Combined waveform of 601 and 602 - Combined waveform in Example 2 - Combined waveform in Example 3 - Combined waveform in Example 4 - Shift clock signal waveform - Polarity switching (No. 1 waveform - Scanning electrode Selection (No. 11 waveform, signal electrode selection waveform, scanning electrode waveform, signal electrode waveform, combined waveform of 1041 and 1042, pixel transmission degree 1, polarity switching signal waveform, scanning electrode selection signal waveform in Example 6) ...Signal electrode selection signal waveform of G and j in Example 6...Scanning electrode selection signal waveform of Example 7...Reference to Example 7 No. 1 electrode selection 1329 ・ 132 l ・ 1 329' 32 l l 308 ・ 1441 ・ 1442 ・ 145 l ・ 1402 ・ 1501 ・ 1502 ・ 1503 ・ 1701 , l 702, Signal waveform...Scanning electrode selection signal waveform in Example 8...Signal electrode in Example 8 Selection signal waveform...Scanning electrode selection signal waveform in Example 9...Signal electrode selection signal waveform in Example 9...Selection pulse switching signal...Scanning electrode waveform...Signal electrode waveform...1441 and 1442(F) Composite wave 11a... Pixel transmittance change... Composite waveform in Example 7... Composite waveform in Example 8 and 13... Composite waveform in Example 9... Clock Signal 1703 ・ l 705 ・ l 707 ・ l 708 ・ l 709 ・ 17 l O・ +711 ・ 17 l 2 ・ ・Drive voltage・Data signal・Latch signal・Part of scanning electrode driver・Part of signal electrode driver・Resistance・Switch・Signal electrode/scanning electrode Applicant: Seiko Epson Co., Ltd. Agent Patent attorney: Y Sanbe Suzuki (and 1 other person) Figure 2 Figure 4 Figure 5 r-as Figure 7?07 Figure 9 3og Figure 13 Figure 15 Figure 16

Claims (4)

[Claims] (1) In a method for driving a liquid crystal element in which a ferroelectric liquid crystal is sandwiched between at least a substrate on which a scanning electrode is formed and a substrate on which a signal electrode is formed, liquid crystal molecules A correction electric field is applied to eliminate the unbalanced charge in the electric field and waveform in which the liquid crystal layer takes the first state, and at the end of the selection period, the saturation voltage and threshold voltage are applied to bring the liquid crystal layer into the second state. The electric field corresponding to A method for driving a liquid crystal element, characterized in that an alternating current smaller than the pulse width (pulse width) is applied. (2) The scanning line is brought into a high impedance state of 100Ω or more with respect to the scanning electrode signal line during the non-selection period, and is brought into a low impedance state of 100Ω or less again after the non-selection period. A method for driving the liquid crystal element described above. (3) From the rear of the non-selection period to the front of the selection period,
If the selection period is divided into three, the first pulse is used, and if the selection period is divided into two, an electric field is applied that makes the total charge of the selection signal zero with the pulse inserted before the selection period. 3. The method of driving a liquid crystal element according to claim 1, wherein when the second pulse is divided into two, an electric field is applied that causes the liquid crystal layer to take the first state with the first pulse. (4) From the rear of the non-selection period to the front of the selection period,
Before the selection period, an electric field is applied that brings the liquid crystal molecules in the first state with uniform charges as a whole waveform, and in the first half of the divided selection period, an electric field that cancels the electric field applied during the second half of the selection period is applied. Claim 1 or 2 characterized in that:
The method for driving a liquid crystal element described in .