JP2900919B2 - Driving method of liquid crystal element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a method for driving a liquid crystal element.
Method, especially for multi-layer electro-optical devices using ferroelectric liquid crystals.
Rex driving method. [0002] BACKGROUND ART Japanese Patent Application Laid-Open No. 56-107216 discloses
The chiral smectic C phase or
Electric charge using ferroelectric liquid crystal showing an iral smectic H phase
The magneto-optical element responds very quickly to the applied voltage,
And is known to have the characteristic of having memory properties
Large-capacity display with a large number of pixels, high speed
Applications to electronic shutters, polarizers, etc. are expected. Conventionally, the driving of such a ferroelectric liquid crystal element has been described.
The method is described in JP-A-58-179890.
That determine the light transmission state of the liquid crystal element
Voltage is applied at a predetermined period and is applied within this predetermined period.
The average value of the applied voltage to zero to prevent the ferroelectric liquid crystal from deteriorating.
A driving method for stopping is known. However, Japanese Patent Laid-Open No.
Specific driving method disclosed in JP-179890A
The method is a static drive method, which drives large-capacity elements.
Multiplex driving method is not disclosed.
Absent. In addition, the ferroelectric liquid crystal element is provided with an applied voltage pulse.
Threshold voltage changes depending on the pulse width
It is known to have so-called pulse width dependence
However, it is described in the above-mentioned JP-A-58-179890.
Drive method takes no account of this pulse width dependence.
And actual driving is difficult. [0004] Therefore, we have disclosed a Japanese Patent Application No. 59-119680.
(See JP-A-60-263124) and Japanese Patent Application
JP-A-60-177818 (JP-A-61-55630)
), Considering the aforementioned pulse width dependence,
A practical multiplex driving method was proposed. [0005] SUMMARY OF THE INVENTION This kind of memory property
The previous frame or field to drive the LCD
To ensure that the alignment state of the liquid crystal selected in
Then, an erasing voltage is applied to the liquid crystal, and the molecules of the liquid crystal are specified.
Are aligned in the array direction. After that, select voltage is applied to the liquid crystal
Is applied to align the liquid crystal molecules according to the display state.
Direction. At this time, delete the display before selecting the display state.
Insufficient leaving action will cause the previous frame or field to
Affected by the alignment conditions selected in the
No indication can be obtained. Accordingly, the present invention is directed to a liquid crystal having a memory property.
The array state selected in the frame or field of
Make sure that it is erased and
With the aim of setting the liquid crystal of the
I do. [0007] According to a first aspect of the present invention, there is provided a scanning apparatus comprising:
Between the substrate having the electrode group and the substrate having the signal electrode group
Driving a liquid crystal element sandwiching liquid crystal with memory properties
In the method of driving a liquid crystal element,
Applying a signal, applying a data signal to the signal electrode group,
By the scanning signal and the data signal, the liquid crystal
An erasing voltage for aligning the pixels in a predetermined arrangement direction;
Select voltage to set the child in the array direction corresponding to the display state and
Is applied to the liquid crystal, and the scanning signal is applied to the erase voltage mark.
A first voltage pulse applied to the scan electrode at the time of
A second voltage applied to the scan electrode when the selection voltage is applied
And the pulse width of the first voltage pulse is a second pulse.
It is set wider than the pulse width of the voltage pulse,
When the intermediate potential of the data signal is used as the reference potential,
The data signal comprises two voltage levels, positive and negative,
During the period in which the first voltage pulse is applied to the electrode,
The data signal having the voltage level inverted with respect to the reference potential;
The signal is applied to the signal electrode. [0008] The invention of claim 2 is based on claim 1, and
The first voltage applied to the scan electrode when the erase voltage is applied
The peak value of the voltage pulse is constant. [0009] The invention of claim 3 is directed to claim 1 or 2.
And applied to the scan electrode when the erase voltage is applied.
When the integral value of the first voltage pulse is applied with the selection voltage,
Integral value of the second voltage pulse applied to the scan electrode
It is characterized by being larger than. [0010] JP-A-58-179890 describes
As shown, the molecules of the ferroelectric liquid crystal
In a helical state, it has an angle of θ with respect to the helical axis
Are arranged as shown in FIG. 1 (a).
When an electric field of negative polarity -E is applied, the molecules of the ferroelectric liquid crystal
1 is relative to the helical axis 2 on a plane perpendicular to the direction of the electric field -E.
Are arranged in a certain direction with an angle θ. Also, the pole of the electric field
When the nature is reversed, as shown in FIG.
The angle is set in a direction symmetrical to the direction of FIG.
Are arranged with a degree θ. At this time, FIG.
As shown in (b), two polarizing plates are placed on the ferroelectric liquid crystal.
Provided below, the direction of the polarization axis of the upper polarizing plate is 3, the lower polarization
The polarization axes of the plates are orthogonal to each other so that the direction of the polarization axis is 4.
Then, the molecules of the ferroelectric liquid crystal are aligned in the direction shown in FIG.
In the case of
When arranged in the direction of (b), the light transmission amount is the highest.
More. In addition, the arrangement of molecules of such ferroelectric liquid crystal
The condition is that the voltage of the opposite polarity threshold or more is applied next.
And it is stable as it is. This is called memory
This is one of the characteristics of the ferroelectric liquid crystal. In order to drive this type of liquid crystal element, the liquid crystal must be driven.
A voltage is applied to the scanning electrode and signal electrode that face each other
Apply a pulse. Then, the liquid crystal molecules are aligned in a predetermined
Erasing voltage to align the liquid crystal molecules according to the display state.
The selection voltage set in the alignment direction is applied to the liquid crystal.
You. Each of the first to third aspects of the present invention will be described with reference to FIGS.
Example shown in 51Is shown symbolically. In each of the first to third aspects of the present invention, the erase voltage
Pulse of the first voltage pulse applied to the scan electrode at the time of application
The width is the second voltage applied to the scan electrode when the selection voltage is applied.
The pulse width is wider than the pulse width. The invention of claim 1
In Example 1 of FIG.ToReferring to FIG. 3,
The voltage waveform applied to the liquid crystal is indicated as (X1-Y1).
I have. For example, taking the period t11 as an example, it is divided into four
The second and third periods t15 and t16 of the period t11 are erased by the liquid crystal.
The fourth period t17 is a period during which the last voltage is being applied.
This is the period during which the selection voltage is applied to the crystal. t21 period
Similarly, the second and third periods t2 of the t21 period divided into four
5, t26 is a period during which the erase voltage is applied to the liquid crystal.
The fourth period t27 is a period during which the selection voltage is applied to the liquid crystal.
Between. That is, the second and third periods (t15 + t1)
6) or (t25 + t26), low transmittance
The directions of the liquid crystal molecules are aligned so that
In the period 7 or t27, the liquid crystal molecules are aligned with the display state.
This is because they are set in the column direction. Applied to the scanning electrode
A voltage pulse waveform shown in FIG.
The second and third periods (t15) to which the pulse (-V1) is applied
+ T16) or (t25 + t27) total length
Is a fourth period t during which the second voltage pulse (+ V1) is applied.
17 or twice the length of t27. This relationship is illustrated
During the periods t11 and t21 shown in FIG.
ThroughYou.Thus, according to the first aspect of the present invention, the erase voltage mark
Pulse width of the first voltage pulse applied to the scan electrode when applying
Is widely secured. Therefore, the wave of the first voltage pulse
Even if the high value is not so large, the effective value of erase voltage
(Loose width x peak value) can be secured large and can be maintained in the previous frame.
It is possible to reliably erase the orientation state of the held liquid crystal.
You. Therefore, the selection voltage applied to the liquid crystal thereafter
Without depending on the state of the liquid crystal in the previous frame.
The liquid crystal molecules in the alignment direction corresponding to the
It becomes possible. Further, another feature of the invention of claim 1 is as follows.
As a feature, for example, as shown in FIG.
(+ V2) and negative (-V2).
You. Therefore, driving the liquid crystal with fewer voltage levels
it can. Further, a first voltage pulse is applied to the scan electrode.
In the period, the intermediate potential (0 V) of the data signal is set as a reference potential.
The positive (+ V2) and negative with respect to the reference potential (0V)
The voltage level of (−V2) is inverted and applied to the signal electrode.
Have been. Thereby, for example, in the case of the first embodiment shown in FIG.
In this case, the positive and negative binary voltage levels
(For example, t in FIG. 3)
(16 periods) to surely reset the alignment of liquid crystal molecules
To reduce the first voltage level applied to the scan electrodes.
There is also an advantage that you can. According to a second aspect of the present invention, for example, the scanning shown in FIG.
Of the waveform (X1) applied to the electrode, when the erase voltage is applied (period
The voltage pulse (-V1) during the period t15, t16) is kept constant.
It is defined that it is held. The invention of claim 3 is, for example, shown in FIG.
Of the waveform (X1) applied to the scan electrode
Product of voltage pulses applied at time (periods t15 and t16)
| V1 | × (t15 + t16) which is the divided value is the selection voltage
Integral value of voltage pulse applied during application (period t17)
| V1 | × t17
You. In the present invention, as shown in FIG.
The polarity of the voltage to align the molecules of the ferroelectric liquid crystal
(-), The electrodes arranged in the direction shown in FIG.
The polarity of the pressure is defined as positive (+),
And the direction of the polarization axis has a relationship as shown in FIG.
And the state with the least amount of light transmission is the off state (or
Or simply off), resulting in the relationship shown in FIG. 1 (b).
And the state with the highest light transmission is the on state (or
Simply on). Of course, the arrangement direction of the molecules and the direction of the polarization axis
Is reversed in FIGS. 1 (a) and (b), the positive
When pressure is applied, the amount of transmitted light is maximized and a negative voltage is applied.
One application minimizes this, but this is simply the voltage polarity and off.
Only the relationship between the on and off states is reversed.
It can be driven qualitatively by the same driving method.
It is included in the range. [0018] FIG. 2 (a) shows each embodiment of the present invention described below.
FIG. 3 is a cross-sectional view illustrating an example of a liquid crystal element used in an example. Gala
Transparent substrates 11 and 12 made of metal or plastic
The opposing inner surfaces of indium oxide or
Are a plurality of transparent scanning electrodes 13 made of tin oxide and
No. electrode 14 is formed. If necessary,
After providing an insulating layer made of silicon oxide or the like on the
An alignment film 15 made of polyimide, nylon, or the like is provided.
Rubbing the surface of the alignment film on one substrate
The conductive liquid crystal 16 was oriented in a predetermined direction. 19 is Epo
It is a sealant made of a xy adhesive. Also, a pair of substrates
On the outer surface where electrodes 11 and 12 are not formed,
Polarizers 17 and 18 were adjacent to each other. At this time,
The polarization axes of the polarizing plate 17 and the polarizing plate 18 are substantially the same.
Make the ferroelectric liquid crystal 16 orthogonal and
Alignment of ferroelectric liquid crystal molecules when a voltage greater than the sum is applied
Direction is parallel to the direction of the polarization axis of one of the polarizers
The direction of the polarization axis of the polarizing plate was set to be as follows. The gap between the substrates, ie, the thickness of the liquid crystal layer
Is about 1.3 μm, and the ferroelectric liquid crystal used is P-tet
Radecyloxybenzylidene-P'-amino- (2-methyl
) -Butyl- (α-cyano) -cinnamate (TDO
BAMBCC). This liquid crystal has a pulse width of 200
The threshold voltage at μsec is 6.5 V and the saturation voltage is 8
V and the threshold when the pulse width is 400 μsec.
The value voltage was 4.2 V and the saturation voltage was 6.3 V. this
The values were almost the same even if the polarity was reversed. The scanning electrode 13 and the signal electrode 14 are shown in FIG.
As shown in (b), each is formed in a stripe shape,
And they were formed so as to be orthogonal to each other. This scanning electrode and signal
A portion where the electrodes overlap in a plane is a pixel. What
FIG. 2 (b) is used to make the following description easier to understand.
The following shows typical types of on and off patterns.
That is, the number of scanning electrodes Xn is 6, and the number of signal electrodes Yn is 3.
However, of course, the present invention is limited to this number of electrodes.
The number of electrodes is determined according to the required number of pixels.
It should be fixed. In FIG. 2 (b), a hatched image
Element is off, other pixels are on.
Is shown. Hereinafter, a specific drive for driving the liquid crystal element will be described.
An example of the operation method will be described. Embodiment 1 FIG. 3 shows an on / off state as shown in FIG. 2 (b).
To be applied to each pixel on the scan electrode X1
4 shows a driving waveform and light transmission characteristics in an example. In addition, light
To make the change in transmission characteristics easier to understand, the following frame
In the memory cycle, the ON and OFF states of all the pixels were inverted. In FIG. 3, t₁₃Is the first frame circumference
Period, t_{twenty three}Indicates the next frame period. Also, t₁₁And t_{twenty one}
Is the selection period, t₁₂And t_{twenty two}Is the non-selection period
Show. Further t₁₄, T_Fifteen, T₁₆, T₁₇, T_{twenty four}, T_{twenty five}, T
₂₆And t₂₇Indicates a pulse width of 200 μsec.
V indicating the peak value₁Is 6V, V_TwoIs 3V
You. The scanning electrode X1 has a selection period t.₁₁(T_{twenty one})
Is ± V₁For the non-selection period t₁₂(T_{twenty two}) Applies 0V,
Signal electrode Y₁, Y_Two, Y_ThreeIf you want to turn on the pixel
If the peak value V_TwoWith a pulse width of 200μsec
Apply in the order of positive, negative, positive, and negative.
When applied in the order of positive, negative, positive, the voltage applied to each pixel
The pulse is (+ V₁-V_Two), (-V₁+
V_Two), (-V₁-V_Two), (+ V₁+ V_Two) In order
And when off, (+ V₁+ V_Two), (-V₁−
V_Two), (-V₁+ V_Two), (+ V₁-V_Two) In order
Become. At this time, (10V₁-V_Two) And (−V₁+
V_Two) Is smaller than the threshold voltage of the liquid crystal.
Therefore, the liquid crystal does not respond, and is higher than the saturation value (+ V₁+
V_Two) And (−V₁-V_Two). But strong
Dielectric liquid crystal responds at high speed and has memory properties.
Apparently higher than the saturation value applied at the end of the selection period
On or off depending on the polarity of the pulse
Will be recognized. In the non-selection period, (+ V₁One V_Two)and
(-V₁+ V_Two) Is applied, and the pulse width is
The maximum value is 400 μsec, but the peak value is 400 μ
Because it is smaller than the threshold voltage at the time of
Has little effect. Also on and off contra
The strike ratio is the area element (X₁Y₁) At 18: 1, (X₁Y_Two)
16: 1, (X₁Y_Three) Is 18: 1, and on and off
Almost constant contrast ratio regardless of the pattern
Was done. In this embodiment, the driving method is selected for liquid crystal.
Period t₁₁(T_{twenty one}Waves at least above the saturation value of the liquid crystal
Apply positive and negative voltage pulses with high value and pulse width
The positive and negative voltage pulses have the same peak value and pulse width.
And apply a positive or negative voltage pulse over the saturation value.
Select on or off in the order
Are equal in number and the non-selection period t₁₂(T_{twenty two}) Is the threshold
Positive and negative voltage pulses with the following peak values and pulse widths
Is applied, as shown in FIG.
The average value becomes zero, and no DC component exists. So liquid
The crystal element was not deteriorated. FIG. 4 shows the driving waveforms shown in FIG.
FIG. 3 is a circuit block diagram of an example of a specific circuit. 111 is
Transmission gate, 112 is flip-flop
And 113, a liquid crystal element. d, h, e, f, g,
j, k, l select transmission gate 111
Then, a scanning electrode signal Vt and a signal electrode signal Vd are formed, and the liquid
Is applied to the crystal element 113. Also ± V₁And zero V, ± V_TwoIs the scanning electrode and
This is the power supply voltage of the signal electrode. FIG. 5 is shown in FIG.
To generate the scanning electrode signal Vt and the signal electrode signal Vd of the circuit
These are the signals at each point. Comparative Example 1 FIG. 6 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁And signal electrode Y₁Applied to
The drive waveform and the surface element (X₁Y₁2) shows the light transmission characteristics. What
To make the change in light transmission characteristics easier to understand, the following
Frame period t_{twenty three}Now, the on and off states are reversed. In FIG. 6, t₁₁~ T₂₇Are both
3 shows the same thing, and the peak value V₁, V_Two,
V_Three, V_Four, V_Five, V₆Are 8V, 6V, 5
V, 3V, 2V and 0V. Vm is marked on the signal electrode.
Indicates the intermediate potential of the applied voltage pulse, in this case 4V
become. The difference from the first embodiment is that the voltage applied to the scanning electrode
Voltage between the scan and signal electrodes to reduce the
The level is the same. Scanning electrode X₁Has a selection period t₁₁(T_{twenty one})
Is V with a pulse width of 200 μsec.₁, V₆, V₆, V
₁, And the non-selection period t₁₂(T_{twenty two}) Is V_Two, V_Five
Are applied in the order shown in the figure. Also, the signal electrode Y₁To
If you want to turn on the pixel,
V_Four, V_Three, V₁, V₆And then turn off
If desired, apply in the reverse order. At this time the pixel
(X₁Y₁) Is (V) when on.₁
-V_Four), (V₆-V_Three), (V₆-V₁), (V₁−
V₆) In order and when off (V₁-V₆), (V₆
-V₁), (V₆-V_Three), (V₁-V_Four)
Of the pulse to be applied later with a pulse equal to or higher than the saturation value.
It is turned on or off depending on the nature. The selection period
(V₁-V_Four) And (V₆-V_Three)
At + 5V and -5V respectively, pulse width 400μs
The pulse is larger than the threshold value of the liquid crystal at the time of c.
Since the width of the pulse is 200 μsec,
Less than the threshold, the liquid crystal does not respond. Also unselected
(V_Five-V₆) And (V_Two-V₁) Pulse
Applied and the pulse width is 4 depending on the on / off pattern.
Although it may be 00 μsec, the peak value is 400 μs
Since it is smaller than the threshold value of the liquid crystal at ec, light transmission characteristics
Has little effect. The driving method according to this comparative example is the same as that of the first embodiment.
A good contrast ratio was obtained. The driving method in this comparative example is selected for liquid crystal.
Period t₁₁(T_{twenty one}Waves at least above the saturation value of the liquid crystal
Apply positive and negative voltage pulses with high value and pulse width
The positive and negative voltage pulses have the same peak value and pulse width.
And apply a positive or negative voltage pulse over the saturation value.
Select on or off in the order
Are equal in number and the non-selection period is t₁₂(T_{twenty two}) The threshold
Positive and negative voltage pulses with peak values and pulse widths less than
Power is applied, regardless of the on / off pattern.
The average value of the applied voltage becomes zero, and the liquid crystal element deteriorates.
Did not occur. FIG. 7 realizes the driving waveforms shown in FIG.
FIG. 3 is a block diagram illustrating an example of a specific circuit. ,of
Select transmission gate 111 by signal
The scan electrode waveform and the scan electrode waveform at the time of
And select a non-selected scan electrode waveform to create a scan electrode waveform.
You. On the other hand, the signal electrode waveform
Select the mission gate 111 and select the signal electrode data
Select the ON waveform and the OFF waveform with
A waveform is formed and applied to the liquid crystal element 113. Also, V₁, V
_Two, V_Three, V_Four, V_Five, V₆Are the scanning and signal electrodes
Power supply voltage. FIG. 8 shows each point of the circuit shown in FIG.
Is the signal at. Comparative Example 2 FIG. 9 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁Drive wave applied to each pixel above
Shows shape and light transmission characteristics. Note that changes in the light transmission characteristics are
The next frame period t_{twenty three}OK
And turned off state. In FIG. 9, t₁₁~ T₂₇Are both
3 shows the same thing, and the peak value V₁Is 9V, V_Two
Is 4V. The difference between Example 1 and Comparative Example 1 is that
Applied during the non-selection period to improve the contrast ratio.
The pulse width of the selected pulse selects the on / off state of the liquid crystal
Greater than the pulse above the saturation value applied to
The point is that it does not become. Scanning electrode X₁Has a selection period t₁₁(T_{twenty one})
Is ± V₁And 0 V is applied during the non-selection period, and the signal electrode
If you want to turn on the pixel, turn off 0V
In the case, the first 400 μsec is 0 V, and the next 400 μs
In ec, −V in 200 μsec increments_Two, + V_TwoApply in order
I do. At this time, the voltage pulse applied to each pixel is
When on, (+ V₁), (-V₁), (-V₁),
(+ V₁), And (+ V₁),
(-V₁), (-V, + V_Two), (+ V₁-V_Two) Order
Get started. (-V₁Ten volts_Two) And (+ V₁-V_Two)
Is smaller than the threshold value of the liquid crystal when the pulse width is 200 μsec.
Because of the low value, the liquid crystal does not respond and t₁₁In the selection period of
Is on and off repeatedly₁₇+ Applied last
V₁Is turned on in response to_{twenty one}During the selection period,
t_{twenty four}After turning on with t_{twenty five}-V applied at₁Respond to
To the off state. During the non-selection period, 0V or
+ V with 200µsec loose width_TwoOr -V_TwoIs applied
But V_TwoIs smaller than the liquid crystal threshold,
Has little effect on gender. The contrast ratio obtained by this comparative example
Is the pixel (X₁Y₁) At 24: 1, (X₁Y_Two) In 2
2: 1, (X₁Y_Three) At 20: 1 and Examples 1 and 2
An even better contrast ratio was obtained. The driving method in this comparative example is selected for liquid crystal.
Period t₁₁(T_{twenty one}Waves at least above the saturation value of the liquid crystal
Apply positive and negative voltage pulses with high value and pulse width
The positive and negative voltage pulses have the same peak value and pulse width.
And apply a positive or negative voltage pulse over the saturation value.
Select on or off in the order
Are equal in number and the non-selection period t₁₂(T_{twenty two}) Is the threshold
Positive and negative voltage pulses with the following peak values and pulse widths
Is applied, regardless of the on / off pattern
The average value that can be applied to the liquid crystal element is zero,
Did not deteriorate. FIG. 10 realizes the driving waveforms shown in FIG.
FIG. 3 is a circuit block diagram of an example of a specific circuit to be implemented.
(A), (c), (i), the transmission
Signals to select the operation gate 111, and those signals
To select the transmission gate 111 and scan
The electrode signal Vt and the signal electrode signal Vd are generated, and the liquid crystal element 1
13 is applied. Also, ± V₁, ± V_Two, 0V is the scanning voltage
This is the power supply voltage for the poles and signal electrodes. FIG. 11 shows each point of the circuit shown in FIG.
Is the signal at. Comparative Example 3 FIG. 12 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁And signal electrode Y₁Applied to
Drive waveform and the pixel (X₁Y₁)
You. In addition, in order to make the change of the light transmission characteristic easy to understand,
And the next frame period t_{twenty three}Now the on and off states are reversed
I let you. In FIG. 12, t₁₁~ T₂₇Are both
The same as FIG. 3 is shown, and the peak value V₁, V_Two, V
_Three, V_Four, V_Five, V₆Are 10V, 8V, 6
V, 4V, 2V, and 0V. Vm is marked on the signal electrode.
Indicates the intermediate potential of the applied voltage pulse, in this case 5V
become. The difference from Comparative Example 2 is that
Voltage of the scan and signal electrodes to reduce the voltage
That is, the pressure level is standardized. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is V₁And V₆And V₁, V₆, V₆, V₁In the order
Selection period t₁₂(T_{twenty two}) Is V_TwoAnd V_FiveTo V_Two, V_Five, V
_Five, V_TwoAnd the signal electrode Y₁Turn on the pixel
If you want_Five, V_Two, V_Two, V_FiveIn order
V if you want_Five, V_Two, V_Three, V_FourApply in order
You. In each case, the pulse width is 200 μsec. At this time
Pixel (X₁Y₁The voltage pulse applied to) has a peak value
The driving method of Comparative Example 2 as shown in FIG.
It has the same waveform. That is, (V₁-V_Five) And (V
₆One V_Two) Is the saturation of the liquid crystal at + 8V and -8V, respectively.
Value or more, (V₁-V_Four) And (V₆-V_Three)
At a pulse width of 200 μsec at 10V and -6V
Smaller than the threshold value, (V_Two-V_Three) And (V_Five−
V_Four) Are the threshold values of the liquid crystal at 12V and -2V, respectively.
It is a sufficiently smaller value. Therefore, the liquid crystal element
Responds in the same manner as in Comparative Example 2 and has the same good control.
The last ratio was obtained. FIG. 13 shows the driving waveforms shown in FIG.
It is a circuit block diagram of an example of the specific circuit which appears. ,
Signal selects transmission gate 111.
Select the scan electrode waveform at the time of
And select the non-selected scan electrode waveform and create the scan electrode waveform.
You. On the other hand, the signal electrode waveform
Select the mission gate 111 and select the signal electrode data
Select the ON waveform and the OFF waveform with
A waveform is created and applied to the liquid crystal element 113. Also, V₁,
V_Two, V_Three, V_Four, V_Five, V₆Is the scanning electrode and signal electrode
Power supply voltage. FIG. 14 shows the circuit shown in FIG.
At each point. [0050]Comparative Example 4 FIG. 15 shows an ON / OFF state as shown in FIG.
Scanning electrode X₁A driving waveform applied to each pixel above,
Shows light transmission characteristics. It should be noted that changes in light transmission characteristics can be understood.
For the sake of simplicity, the next frame period t_{twenty three}So, on, oh
State was reversed. In FIG. 15, t₁₃Is the first frame
Period, t_{twenty three}Indicates the next frame period. Also t₁₁and
t_{twenty one}Is the selection period, t₁₂And t_{twenty two}Is a period outside the selection period
And furthermore, this period t₁₂And t_{twenty two}Is the non-selection period t
₁₆And t₂₆Immediately before the next selection period, that is, the frame
Erasing period t provided at the end of the period_FifteenAnd t_{twenty five}Two periods
Are divided into t₀₅Is the first frame period t₁₃of
This shows the immediately preceding erase period. t₁₄Is 200 μsec
Indicates the pulse width. The peak value V₁Is 11V, V_TwoIs 6V,
V_ThreeIs 2.5V. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is ± V_Two, Non-selection period t₁₆(T₂₆) Is 0 V, erasing period t
₀₅(T_Fifteen, T_{twenty five}) Is ± V₁And the signal electrode Y₁,
Y_Two, Y_ThreeIf you want to turn on the pixel,_ThreeTo
To turn off in the order of positive and negative, apply in the order of negative and positive
I do. At this time, each pixel has a selection period t.₁₁(T_{twenty one}Just before)
Erase period t₀₅(T_Fifteen, T_{twenty five}) Indicates that all values are below the saturation value.
(+ V₁-V_Three) And (−V₁+ V_Three) Or
(+ V₁+ V_Three) And (−V₁-V_Three) Is applied,
Selection period t₁₁(T_{twenty one}), When on (−V₁+
V_Three) And (ten volts)₁-V_Three) Is off (−V_Two
+ V_Three) And (+ V_Two-V_Three) Is applied during the non-selection period
Interval t₁₆(T₂₆), ± V depending on the ON / OFF pattern
_ThreeIs 200μsec or 400μsec pulse width
Applied. ± V_ThreeIs greater than the threshold value at 400 μsec.
Since the pulse width is small, the pulse width becomes 400 μsec.
However, it hardly affects the light transmission characteristics. The driving method according to this embodiment is performed immediately before the selection period.
Turn the pixel on, then off, and immediately
Apply a pulse with a positive saturation value or more within the selection period of
Inverts to ON state by applying pulse below threshold
Or keep the off state as is.
Therefore, as compared with the driving methods of Example 1 and Comparative Examples 1 to 3,
The time of the selection period can be halved, and
This is effective when motion is required or when the number of scanning electrodes is increased.
It is a driving method. The erasing period t₀₅(T_Fifteen, T_{twenty five}Applied to
The peak value of the pulse to be applied depends on the on / off pattern.
Although different, both are above the saturation value, so the light transmission amount is
does not change. Further, in this embodiment, the liquid crystal is
Is turned on and off by applying a pulse equal to or higher than the saturation value of
Therefore, the contrast ratio slightly decreases, but the number of scanning electrodes decreases.
As the number increases, the contrast reduction rate decreases,
A good contrast ratio can be obtained. In the case of this comparative example,
Element (X₁, Y₁) At 17: 1, (X₁Y_Two) At 16:
1, (X₁, Y_Three) Gives a contrast ratio of 17: 1
Was. Also in this comparative example, the voltage is applied to the liquid crystal.
The average value of the voltage becomes zero, which causes deterioration of the liquid crystal element.
It's gone. In this comparative example, the erasing period is set to the frame period.
Set at the end of the period, just before the next selection period,
When applied to equipment, the time when human eyes cannot identify
If it is within the range, it does not need to be immediately before the selection period. FIG. 16 shows the driving waveforms shown in FIG.
FIG. 3 is a circuit block diagram illustrating an example of a specific circuit to be implemented.
, The transmission gate 111
Select the scan electrode data, select the scan electrode
The waveform and the scanning electrode waveform at the time of non-selection of 0 V are selected, and the scanning
Make a polar waveform. On the other hand, the signal electrode waveform
Select the transmission gate 111 and the signal electrode
In the data, select the ON waveform and the OFF waveform, and
A signal waveform is generated and applied to the liquid crystal element 113. or,
± V₁, ± V_Two, ± V_Three, 0V are the scanning electrode and the signal
It is the power supply voltage of the pole. FIG. 17 shows the circuit shown in FIG.
It is a signal at each point on the road. Comparative Example5 FIG. 18 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁, X_TwoAnd the signal electrode Y1
The applied drive waveform and the pixel (X₁Y₁) Light transmission characteristics
Is shown. Note that the change in light transmission characteristics is easy to understand.
For the next frame period t_{twenty three}Now reverse the on / off state
I let it. In FIG. 18, t₀₅~ T₂₆Are both
This shows the same as FIG. 15, and t ′₀₅And t '_Fifteen
Is the scanning electrode X_TwoIn the second non-selection period, t ′₁₁And
And t '_{twenty one}Is also the selection period, t '₁₆Is the first non-selection period
Interval, t '₁₂Is the frame containing the first and second non-selection periods
3 shows a non-selection period in the program cycle. Peak value V₁, V_Two, V_Five, V₆Are each
12V, 10V, 2V, 0V_ThreeAnd V_FiveIs
8V, V_FourAnd V₉Is 4V. Vm is applied to the signal electrode
Indicates the intermediate potential of the applied voltage pulse, in this case 6
V. [0062]Comparative Example 4The difference from the
Voltage of the scan and signal electrodes to reduce the voltage
That is, the pressure level is standardized. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is V_FourAnd V_ThreeFor the first non-selection period t₁₆(T₂₆)
Is V_TwoAnd V_FiveFor the second non-selection period t₀₅(T_Fifteen,
t_{twenty five}) Is V₁And V₆Is applied. Scan electrode X₁To
Assuming that the odd-numbered scan electrodes are the even-numbered scan electrodes,
X_TwoAs shown in FIG.₁Phase is opposite to
Is applied. This is the scan electrode X₁Upper pixel
Is the selection period t₁₁(T_{twenty one}), The scanning electrode X_TwoPicture above
The element is the second non-selection period t '₀₅(T '_FifteenAt this time
At the saturation value or higher to turn the pixel on and off
This is for applying a voltage. That is, in this comparative example,
It is necessary to alternately apply opposite-phase pulses to the
You. As a result, the signal electrode Y₁Pulse applied to
Is an odd pulse for turning on and off the pixel.
Pixels on the number-th scan electrode and pixels on the even-number scan electrode
It is necessary to make the waveform different from the element. That is, an odd number
Th scan electrode (eg, X₁) Turn on the upper pixel
If V₁And V₆To V₁, V₆Turn off
If V₈And V₉To V₈, V₉In the order of
Th scan electrode (eg, X_Two) Turn on the upper pixel
If V₈And V₉To V₉, V₈Place to turn off
If V₁And V₆To V₆, V₁Are applied in this order. This
, The pixel (X₁Y₁The pulse applied toComparative Example 4
Apply only the same pulse except for the peak value
Is done. That is, in the case of ON, the selection period t₁₁Then (V
_Four-V₁) And (V_Three-V₆) Greater than negative or positive saturation value
Is applied, and when it is off, the selection period t_{twenty one}Then
(V_Four-V₈) And (V_Three-V₉) Negative and positive threshold
A pulse with a value less than the value is applied. Also, the selection period
The second selection period t immediately before₀₅(T_Fifteen, T_{twenty five}), (V
₁-V_Four) And (V₆-V₈) Or (V₁−
V₆) And (V₆-V₁) Is a value above the saturation value.
Pixels are applied in the order of positive and negative, and the pixel is turned on once
Turns off and then turns off in the next selection period.
To turn off or keep the off state.
You. First selection period t₁₆(T₂₆)Comparative example
4In the same way as in
(V) having a width of 200 μsec or 400 μsec_Five-V
₆) And (V_Two-V₁) Or (V_Two-V₈) And
(V_Five-V₉) For 400 μsec pulse width
Is applied. The driving method of this comparative example is as follows.Comparative Example 4the same as,
When higher speed drive is required or more scan electrodes are required
It is a driving method that is effective for width,Comparative Example 4Control similar to
The last ratio was obtained. FIG. 19 illustrates the driving waveforms shown in FIG.
FIG. 3 is a block diagram illustrating an example of a specific circuit to be implemented. ,
Transmission gate 111 is selected by the signal of
The scan electrode waveform and the scan electrode waveform at the time of
Select the scan electrode waveform when not selected, and change the scan electrode waveform.
create. Note that these are even-numbered scan electrode selection waveforms. on the other hand
The signal electrode waveform is
Gate 111 is selected and the signal electrode data
Select ON waveform and 10 OFF waveforms to create signal electrode waveform.
Is applied to the liquid crystal element 113. Also, V₁, V_Two, V
_Three, V_Four, V_Five, V₆, V₈, V₉Is the scanning electrode and signal
This is the power supply voltage of the electrode. FIG. 20 shows the structure shown in FIG.
These are signals at each point of the circuit. Comparative Example6 FIG. 21 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁Drive applied to each pixel above
The waveform and light transmission characteristics are shown. Note that the change in light transmission characteristics
For clarity, the next frame period t_{twenty three}Then
The on and off states were reversed. In FIG. 21, t₀₅~ T₂₆Is
Also shows the same as FIG. 15, and the peak value V₁Is 8
V, V_TwoIs 4V. [0069]Comparative Example 4And comparative examples5Is different from
Applied during the non-selection period to improve the contrast ratio.
The pulse width of the applied pulse turns on and off the liquid crystal.
Not greater than the pulse above the saturation value applied to
That's the point. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is ± V₁, The first non-selection period t₁₆(T₂₆) Is 0V,
2 non-selection period t₀₅(T_Fifteen, T_{twenty five}) Is ± V₁The selection period
The signal electrode Y is applied in the reverse order.₁, Y_Two, Y_ThreeTo
Is 0V if you want to turn on the pixel, and if you want to turn it off
Is ± V_TwoAre applied in the order of negative and positive. At this time, each pixel has
Selection period t₁₁(T_{twenty one}) Immediately before the second non-selection period t
₀₅(T_Fifteen, T_{twenty five}) Indicates that ± V is equal to or higher than the saturation value.₁Also
Or (+ V₁+ V_Two) And (−V₁-V_Two) Is applied
And the selection period t₁₁(T_{twenty one}), When on, ± V
₁Is off (−V₁+ V_Two) And (+ V₁-V
_Two) Is applied to the first non-selection period t₁₆(T₂₆)
According to the ON / OFF pattern, (+ V₁-V_Two)and
(-V₁Ten volts_Two) Or 0V is applied. like this
In the non-selection period, the pulse width is larger than 200 μsec.
Pulse is not applied and gives to the light transmission characteristics
The effect is smaller. The driving method of this comparative example is alsoComparative Example 4And ratio
Comparative example5As before, the pixel is turned on just before the selection period.
To the off state, and within the selection period immediately after that,
Apply a pulse that is equal to or greater than the sum, or a pulse that is less than
To the on state or the off state
Since it is selected whether to keep the state as it is, the first embodiment and
The time of the selection period is reduced by half compared to the driving methods of Comparative Examples 1 to 3.
If you need a faster drive,
This is an effective driving method when increasing the number of scanning electrodes. In the case of this comparative example, the pixel (X₁Y₁) In 2
2: 1, (X₁Y_Two) At 21: 1, (X₁Y_Three) In 2
A contrast ratio of 0: 1 was obtained. In this comparative example,
The average value of the voltage applied to the liquid crystal becomes zero,
There was no deterioration of the device. Note that, also in this comparative example, the second non-selection period is
Set at the end of the frame cycle, that is, immediately before the next selection period
However, when applied to display devices, human eyes cannot be identified.
If it is within the time range, it is not necessary to be immediately before the selection period
Absent. FIG. 22 illustrates the driving waveforms shown in FIG.
FIG. 2 is a circuit block diagram illustrating an example of a specific circuit to be implemented;
, The transmission gate 111
Select the scan electrode data, select the scan electrode
The waveform and the scanning electrode waveform at the time of non-selection of 0 V are selected, and the scanning
Make a polar waveform. On the other hand, the signal electrode waveform
Select the transmission gate 111 and select the signal electrode
Select ON waveform and OFF waveform for data and
A signal waveform is generated and applied to the liquid crystal element 113. or,
± V₁, ± V_Two, 0V, radio waves of scanning electrode and signal electrode
Voltage. FIG. 23 shows various points of the circuit shown in FIG. 22.
Is the signal at. Comparative Example7 FIG. 24 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁, X_TwoAnd signal electrode Y₁To
The applied drive waveform and the pixel (X₁Y₁) Light transmission characteristics
Is shown. Note that the change in light transmission characteristics is easy to understand.
For the next frame period t_{twenty three}Now reverse the on / off state
I let it. In FIG. 24, t₀₅~ T₂₆And t '
₀₅~ T '_{twenty one}Indicate the same as in FIG. Peak value V₁, V_Two, V_Three, V_Four, V_Five, V
₆Are 10V, 9V, 7V, 3V, 1V, 0V respectively
is there. Vm is the intermediate voltage of the voltage pulse applied to the signal electrode.
In this case, it is 5V. Comparative Example6The difference from the
Voltage of the scan and signal electrodes to reduce the voltage
That is, the pressure level is standardized. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is V_FourAnd V_ThreeFor the first non-selection period t₁₆(T₂₆)
Is V_TwoAnd V_FiveFor the second non-selection period t₀₅(T_Fifteen,
t_{twenty five}) Is V₁And V₆Is applied. Scan electrode X₁To
Assuming that the odd-numbered scan electrodes are the even-numbered scan electrodes,
X_TwoAs shown in FIG.₁Phase is opposite to
Is applied. This is the scan electrode X₁Upper pixel
Is the selection period t₁₁(T_{twenty one}), The scanning electrode X_TwoPicture above
The element is the second non-selection period t '_{twenty five}(T '_Fifteen) And this
At times above the saturation value to turn the pixel on and off.
This is for applying a loose. That is, in this comparative example,
It is necessary to alternately apply opposite-phase pulses to the scan electrodes.
You. As a result, the signal electrode Y₁Pulse applied to
Is an odd pulse for turning on and off the pixel.
Pixels on the number-th scan electrode and pixels on the even-number scan electrode
It is necessary to make the waveform different from the element. That is, an odd number
Th scan electrode (eg, X₁) Turn on the upper pixel
If V₁And V₆To V₁, V₆Turn off
If V_TwoAnd V_FiveTo V_Two, V_FiveIn the order of
Th scan electrode (eg, X_Two) Turn on the upper pixel
If V_TwoAnd V_FiveTo V_Five, V_TwoPlace to turn off
If V₁And V₆To V₆, V₁Are applied in this order. This
Pixel (X₁Y₁The pulse applied to the
If the selection period t₁₁Then (V_Four-V₁) And (V_Three-V
₆) A pulse with a negative or positive saturation value or more is applied,
In the case, the selection period t_{twenty one}Then (V_Four-V_Two) And (V_Three−
V_Five) Pulses with values smaller than the negative and positive thresholds are applied
Is done. Further, a second selection period t immediately before the selection period
₀₅(T_Fifteen, T_{twenty five}), (V₁-V_Five) And (V₆−
V_Two) Or (V₁-V₆) And (V₆-V₁)of
In each case, pulses having a saturation value or more are applied in the order of positive and negative,
The pixel is turned on once, then turned off, and
During the selection period of
Choose to keep. First selection period t₁₆(T₂₆) Is a comparative example
6In the same way as described above, 0 V
Or (V_Five-V₆) And (V_Two-V₁LCD)
Positive and negative pulses of a value sufficiently smaller than the threshold are applied.
You. The driving method of this comparative example is alsoComparative Example 4, Comparative example
5,6As in the case where higher speed driving is required or scanning
This is an effective driving method when increasing the number of electrodes.6
The same contrast ratio was obtained. FIG. 25 shows the driving waveforms shown in FIG.
FIG. 3 is a block diagram illustrating an example of a specific circuit to be implemented. ,
Transmission gate 111 is selected by the signal of
The scan electrode waveform and the scan electrode waveform at the time of
Select the scan electrode waveform when not selected, and change the scan electrode waveform.
create. Note that these are even-numbered scan electrode selection waveforms. on the other hand
The signal electrode waveform is
Gate 111 is selected and the signal electrode data
Select ON waveform and 10 OFF waveforms to create signal electrode waveform.
Is applied to the liquid crystal element 113. Also, V₁, V_Two, V
_Three, V_Four, V_FiveIs the electrode voltage of the scanning and signal electrodes.
You. FIG. 26 is a circuit diagram of the circuit shown in FIG.
Signal. Comparative Example8 FIG. 27 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁Drive applied to each pixel above
The waveform and light transmission characteristics are shown. Note that the change in light transmission characteristics
For clarity, the next frame period t_{twenty three}Is
And turned off state. In FIG. 27, t₁₃Is the first frame
Period, t_{twenty three}Indicates the next frame period. Also t₁₁and
t_{twenty one}Is the selection period, t₁₂And t_{twenty two}Indicates a non-selection period,
t₁₄Indicates a pulse width of 200 μsec. Also t_FifteenAnd
And t_{twenty five}Immediately before the next selection period, that is, at the end of the frame period.
To apply a pulse for average value correction provided later
Indicates the period. In this case, the period is 200 μsec.
You. The peak value V₁Is 1 OV, V_TwoIs 8V,
V_ThreeAnd V_FourIs 2V. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is + V₁, -V_TwoIn the order of non-selection period t₁₂(T_{twenty two}) Is
0V is applied and the last period t of the frame cycle_Fifteen(T_{twenty five})
Is -V as a correction pulse._ThreeIs applied. Signal electrode
Y₁, Y_Two, Y_ThreeIf you want to turn on the pixel,
To turn off 4V in order of positive and negative, in order of negative and positive
Is applied. At this time, when on, each pixel has a saturation value
The above pulse (+ V₁-V_Four) Threshold after applied
A smaller pulse (-V_Two+ V_Four) Applied and off
In each case, the pulse (+ V₁+ V_Four)
And (-V_Two-V_Four) Are applied in the order of positive and negative. Also
Non-selection period t₁₂(T_{twenty two}) Depends on the on / off pattern.
± V_FourIs 200μsec or 400μsec pal
Applied at the end of the frame period t
_Fifteen(T_{twenty five}) Is the correction pulse -V_ThreeWas added
(−V_Three-V_Four) Or (-V_Three+ V_Four)
-4V or 0V is applied. In this comparative example, the pixel is turned off at the beginning of the selection period.
Apply a first pulse that is greater than or equal to the positive polarity saturation value.
And then a second pulse of opposite polarity and a different peak value
And make this second pulse below the threshold,
ON or OFF is selected depending on whether the saturation value is exceeded. this
Hour, on, off, crest value of first pulse
And the difference between the peak values of the second pulse and the second pulse are equalized.
Minutes to t_Fifteen(T_{twenty five}) To correct for 1
The average value of the voltage applied within the frame period is set to zero
You. In this comparative example, the pulse of the correction pulse was used.
Width, the pulse width of the first pulse and the second pulse
Equal, but not necessarily limited to this
Ku, V₁・ T₁|-| V_Two・ T_Two| = | V_Three・ T_Three|
(However, t₁, T_Two, T_ThreeIs the pulse of each pulse
The peak value of each pulse and the
And the pulse width. The driving method of this comparative example is alsoComparative Example 4And comparison
An example5-7Similarly to the driving method of Example 1 and Comparative Examples 1 to 3,
You can halve the duration of the selection period,
When higher speed drive is required or more scan electrodes are required
This is an effective driving method in the case. In addition, the drive of Comparative Examples 1 to 3
Pixels turn on and off during the non-selection period.
The light transmission amount in a very short time.
For applications such as liquid crystal shutters that pose a quality problem
This is an effective driving method. In the case of this comparative example, the pixel (X₁Y₁) In 2
0: 1, (X₁Y_Two) At 17: 1, (X₁Y_Three) In 2
A contrast ratio of 0: 1 was obtained. In this comparative example,
Selects the correction pulse at the end of the frame period, that is, the next selection.
Is applied immediately before the selection period.
Since the pulse hardly affects the light transmission characteristics,
It can be applied with any timing within the non-selection period.
good. FIG. 28 shows the driving waveforms shown in FIG.
FIG. 3 is a block diagram illustrating an example of a specific circuit to be implemented. scanning
The scan electrode data signal 121 is applied to the electrodes.
Transfer to the shift register 115 with the clock signal 120
The waveform of d during the selection period, 0 V during the non-selection period, and the selection period
Switching the voltage to correct the DC component immediately before
Output waveform. On the other hand, the signal electrode
Signal 117 by the signal electrode shift clock 118
Data for one scanning line.
Latch 116 with the latch signal 119, and
The transmission gate 111 is switched on or off.
(B or c waveform) is output. V₁, -V_Two, -V
_Three, ± V_FourIs the drive voltage for the scan and signal electrodes.
You. FIG. 29 shows the signals of the circuit shown in FIG.
FIG. 4 is a timing chart showing waveforms. Comparative Example9 FIG. 30 shows an on / off state as shown in FIG.
Scanning electrode X for₁And signal electrode Y₁Applied to
The driving waveform and the pixel (X₁Y₁2) shows the light transmission characteristics. What
To make the change in light transmission characteristics easier to understand, the following
Frame period t_{twenty three}Then, the on and off states were reversed. In FIG. 30, t₁₁~ T_{twenty five}Are both
The same thing as FIG. 27 is shown. Peak value V₁, V_Two, V_Three, V_Four, V_Five, V
₆, V₇Are 12V, 10V, 8V, 6V, 4
V, 2V and 0V. Vm is the voltage applied to the signal electrode.
Indicates the intermediate potential of the pressure pulse, in this case 5V. Comparative Example8The difference from the
Voltage of the scan and signal electrodes to reduce the voltage
That is, the pressure level is standardized. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is V₁, V₇In the order of non-selection period t₁₂(T_{twenty two}) Is V
_Five, V_Three, And t_Fifteen(T_{twenty five}) Period is for correction
V as a pulse_FourIs applied. Signal electrode Y₁Has a pixel
If you want to turn on_Five, V_FourIn the order of
If not, V₇, V_TwoAre applied in this order. At this time, each pixel
Is a pulse (V₁-V_Five)
Is applied, a pulse (V₇-V
_Four) Is applied.
Luz (V₁-V₇) And (V₇-V_Two) Is like the figure
It is applied in order. In addition, the non-selection period t₁₂(T_{twenty two})
By the off-pain evening (V₆-V₇) And (V_Three
-V_Two) Is 200μsec or 400μsec pal
Applied at the end of the frame period t
_Fifteen(T_{twenty five}) Is the correction pulse V_FourWas added
(V_Four-V_Two) Or (V_Four-V_Four) Ie -4
V or 0 V is applied. This comparative example is also a comparative example.8Like during the selection period
The difference between the peak values of the applied positive and negative pulses is t
_Fifteen(T_{twenty five}), And applied within one frame period.
The average value of the applied voltage is set to zero. The driving method of this comparative example is the same as that of the comparative example.8the same as,
When applied to liquid crystal shutters, etc., use an effective driving method
Yes, comparative example8The same contrast ratio was obtained. FIG. 31 shows the driving waveforms shown in FIG.
FIG. 3 is a block diagram illustrating an example of a specific circuit to be implemented. of
Select transmission gate 111 by signal
The scanning electrode waveform at the time of selection in the scanning electrode data and
When not selected, select the scan electrode waveform and create the scan electrode waveform.
You. On the other hand, the signal electrode waveform
Selection of the gate 111
Select ON waveform and OFF waveform to create signal electrode waveform.
Is applied to the liquid crystal element 113. Also, V₁, V_Two, V
_Three, V_Four, V_Five, V₆, V₇Are the scanning and signal electrodes
Power supply voltage. FIG. 32 is a circuit diagram of the circuit shown in FIG.
It is a signal at each point. Comparative Example10 FIG. 33 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁Drive applied to each pixel above
The waveform and light transmission characteristics are shown. Note that the change in light transmission characteristics
For clarity, the next frame period t_{twenty three}Then
The on and off states were reversed. In FIG. 33, t₁₁~ T_{twenty five}Is
Also shows the same as FIG. 27, and the peak value V₁Is 8
V, V_TwoIs 6V, V_ThreeAnd V_FourIs 2V. Comparative Example8And comparative examples9Is different from
Applied during the non-selection period to improve the contrast ratio.
The pulse width of the applied pulse turns on and off the liquid crystal.
Not greater than the pulse above the saturation value applied to
That's the point. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is 10V₁, -V_TwoIn the order of non-selection period t₁₂(T_{twenty one}) Is
0 V and t_Fifteen(T_{twenty five}) Period is a correction pulse
-V_ThreeIs applied. Signal electrode Y₁, Y_Two, Y_ThreeIn
0V to turn on the pixel, ±
V_FourAre applied in the order of negative and positive. At this time, each pixel is turned on.
In the case of, the pulse + V equal to or higher than the saturation value₁After is applied,
Pulse -V smaller than threshold_TwoIs applied and off
In each case, a pulse having a saturation value or more is (+ V₁+ V_Four),
(-V_Two-V_Four). In addition, the non-selection period t
₁₂(T_{twenty two}) Indicates the pulse width depending on the on / off pattern.
200 μsec pulse ± V_FourOr 0V is applied
But the last period t of the frame period_Fifteen(T_{twenty five}) Only
Correction pulse -V_ThreeIs added, (−V_Three−
V_Four) Or -V_ThreeIs applied. In this comparative example, too,
Greater than the positive polarity saturation value that turns on the pixel at the beginning of the selection period
After applying the first pulse of
A second pulse having a different value is applied, and this second pulse is
ON or OFF depending on whether it is below the threshold or above the saturation value.
Is selected. At this time, whether it is on or off
The difference between the peak value of the first pulse and the peak value of the second pulse
And make this difference t_Fifteen(T_{twenty five}) Period
Correction is applied within one frame period
The average value of the voltage is set to zero. In this comparative example, the pulse of the correction pulse was used.
Width, the pulse width of the first pulse and the second pulse
Equal, but not necessarily limited to this
Ku, V₁・ T₁|-| V_Two・ T_Two| = | V_Three・ T_Three|
(However, t₁, T_Two, T_ThreeIs the pulse of each pulse
Indicate the width. ) To satisfy the peak value of each pulse.
And the pulse width may be set. The driving method of this comparative example is the same as that of the comparative example.8And ratio
Comparative example9As compared with the driving method of Example 1 and Comparative Examples 1 to 3,
You can halve the duration of the selection period.
When high-speed driving is required or when scanning electrodes are increased.
This is an effective driving method. Driving method of Comparative Examples 1 to 3
Pixels turn on and off during the non-selection period.
No change in light transmission amount in a very short time
When applied to a problematic liquid crystal shutter,
This is an effective driving method. In the case of this comparative example, the pixel (X₁Y₁) In 2
4: 1, (X₁Y_Two) At 23: 1, (X₁Y_Three) In 2
A contrast ratio of 3: 1 was obtained. In the case of this comparative example,
In this case, the timing for applying the correction pulse
Is not limited to immediately before. FIG. 34 shows the driving waveforms shown in FIG.
FIG. 3 is a block diagram illustrating an example of a specific circuit to be implemented. scanning
The scan electrode data signal 121 is applied to the electrodes.
Transfer to the shift register 115 with the clock signal 120
The waveform of d during the selection period, 0 V during the non-selection period, and the selection period
Switching the voltage to correct the DC component immediately before
Output waveform. On the other hand, the signal electrode
Signal 117 by the signal electrode shift clock 118
Data for one scanning line.
Latch 116 with the latch signal 119, and
The transmission gate 111 is switched on or off.
(B or c waveform) is output. V₁, -V_Two, -V
_Three, V_FourIs the drive voltage for the scan and signal electrodes.
You. FIG. 35 shows the signals of the circuit shown in FIG.
FIG. 4 is a timing chart showing waveforms. Comparative Example11 FIG. 36 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁And signal electrode Y₁Applied to
Drive waveform and the pixel (X₁Y₁)
You. In addition, in order to make the change of the light transmission characteristic easy to understand,
And the next frame period t_{twenty three}Now the on and off states are reversed
I let you. In FIG. 36, t₁₁~ T_{twenty five}Are both
The same thing as FIG. 27 is shown. The peak value V₁, V_Two, V_Three, V_Four, V₆, V
₇Are 10V, 8V, 6V, 4V, 2V, 0V respectively
It is. Vm is the middle of the voltage pulse applied to the signal electrode
Potential, which in this case is 4V. Comparative Example10The difference is that it is applied to the scanning electrode.
In order to reduce the applied voltage, scan electrodes and signal electrodes
That is, the voltage levels are shared. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is V₁, V₇In the order of non-selection period t₁₂(T_{twenty two}) Is V
₆, V_Three, And t_Fifteen(T_{twenty five}) Period is for correction
V as a pulse_FourIs applied. Signal electrode Y₁Has a pixel
If you want to turn on V₆, V_ThreeWant to turn off
If V₇, V_TwoAre applied in this order. At this time, each pixel
Is a pulse (V₁-V₆)
Is applied, a pulse (V₇-V
_Three) Is applied.
Luz (V₁-V₇) And (V₇-V_Two) But as shown
Are applied in the proper order. In addition, the non-selection period t₁₂(T_{twenty two})
(V)₆-V₇) And (V
_Three-V_Two) Or 0 V is applied, but the frame period
Last period t of_Fifteen(T_{twenty five}) Is the correction pulse V_ThreeBut
(V_Four-V_Two) Or (V_Four−
V_Three) Is applied. This comparative example is also a comparative example.10Like the selection period
The difference between the peak values of the positive and negative pulses applied to_Fifteen
(T_{twenty five}), And is applied within one frame period.
Voltage is zero. The driving method of this comparative example is the same as that of the comparative example.10Same as
Effective driving method when applied to liquid crystal shutters
Method and a comparative example10The same contrast ratio as
Was. FIG. 37 shows the driving waveforms shown in FIG.
FIG. 3 is a block diagram illustrating an example of a specific circuit to be implemented. of
Select transmission gate 111 by signal
And the scanning electrode waveform at the time of selection with the scanning electrode data and
When not selected, select the scan electrode waveform and create the scan electrode waveform.
You. On the other hand, the signal electrode waveform
Selection of the gate 111
Select ON waveform and OFF waveform to create signal electrode waveform.
Is applied to the liquid crystal element 113. Also, V₁, V_Two, V
_Three, V_Four, V₆, V₇Is the power supply for the scanning and signal electrodes.
Pressure. FIG. 38 shows each point of the circuit shown in FIG.
Signal. Comparative Example12 FIG. 39 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁And signal electrode Y₁Applied to
Drive waveform and the pixel (X₁Y₁)
You. In addition, in order to make the change of the light transmission characteristic easy to understand,
And the next frame period t_{twenty three}Now the on and off states are reversed
I let you. In FIG. 39, t₁₃Is the first frame
Period, t_{twenty three}Indicates the next frame period, and t₁₁And t_{twenty one}
Is the selection period, t₁₂And t_{twenty two}Indicates a non-selection period. Ma
T₁₄Indicates a pulse width of 200 μsec. Crest value V₁Is 30V, V_TwoIs 12V
You. The feature of this comparative example is that the frequency 1
Applying a high-frequency AC pulse of 0 KHz
By improving the memory performance of the
It has been improved. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is 0 V during the non-selection period t.₁₂(T_{twenty two}) Is ± V₁Exchange pa
And apply the signal electrode Y₁± V_TwoTurn on the pixel
If you want to turn it off, positive, then negative,
Apply in positive order. At this time, the pixel (X₁Y₁)
Lus is ± V when on_TwoAre turned off in the order of negative and positive
In the non-selection period, positive peaks are applied in the order of positive and negative.
If the value is (+ V₁+ V_Two) And the negative peak value is (−V₁+ V_Two)
Pulse and the positive peak value are (+ V₁-V_Two) With negative wave
High value is (-V₁Ten volts_Two) AC pulse is t₁₄Without period
Are applied alternately. The pulse applied during the selection period is
Both are above the saturation value, but the last applied pulse
ON or OFF is selected depending on the polarity of the signal. Also non-selection period
The peak value of the AC pulse applied between them is very large
But the pulse width is very small at 50 μsec.
The liquid crystal device does not respond, and the memory is improved.
The contrast ratio is improved. In this comparative example, 40:
An extremely excellent contrast ratio of 1 was obtained. Further, the voltage pulse applied to the liquid crystal element is
The average value is zero.
Was. FIG. 40 shows the driving waveforms shown in FIG. 39.
It is a circuit block diagram of an example of the specific circuit which appears. ,
Signal selects transmission gate 111.
Select the scan electrode data at 0 V when the scan electrode data is
Select the scan electrode waveform when the shape and non-selection
Make shape. On the other hand, the signal electrode waveform
With the signal electrode data of selecting the mission gate 111
Select the ON waveform and the OFF waveform of
And applied to the liquid crystal element 113. ± V₁, ± V_Two,
0V is a power supply voltage of the scanning electrode and the signal electrode. No. 41
The figure shows the signals at each point of the circuit shown in FIG.
You. Comparative Example13 FIG. 42 shows an on / off state as shown in FIG. 2 (b).
Scanning electrode X₁And signal electrode Y₁Applied to
Drive waveform and the pixel (X₁Y₁)
You. In addition, in order to make the change of the light transmission characteristic easy to understand,
And the next frame period t_{twenty three}Now the on and off states are reversed
I let you. In FIG. 42, t₁₃Is the first frame
Period, t_{twenty three}Indicates the next frame period, and t₁₁And t_{twenty one}
Is the selection period, t₁₂And t_{twenty two}Indicates a non-selection period. Further, t₁₄Gives a pulse width of 200 μsec
Show. Comparative Example12Is different from the selection period t
₁₁(T_{twenty one}) Difference between the peak values of the positive and negative pulses applied to
For the non-selection period t₁₂(T_{twenty two}High frequency AC applied to
The point is that it is corrected with a pulse.
Peak value V₁And V_FourIs | V_Three・ T₁₄|-| V_Two・
t₁₄| = 1/2 (| V₁・ T₁₂|-| V_Four・ T₁₂|)
Set to satisfy. In the case of this comparative example, t₁₂= 1
0t₁₄The peak value V₁, V_Two, V_Three, V_FourTo
30V, 10V, 20V and 28V respectively. Also,
V_FiveIs 5V. Scan electrode X₁Has a selection period t₁₁(T_{twenty one})
Is -V_ThreeAnd V_TwoIs the non-selection period t in the order of negative and positive
₁₂(T_{twenty two}) Indicates that the positive peak value is V₁, The negative peak value is V_Fourso
An AC pulse having a frequency of 10 KHz is applied, and the signal electrode Y₁
Has ± V_FiveIf you want to turn on the pixel,
If it is desired to turn off, apply in the order of negative and positive. At this time,
Pixel (X₁Y₁) Indicates that when on, (−)
V_Three-V_Five) And (ten volts)_TwoTen volts_Five) Applied and off
In the case of, a negative pulse (−V_Three+ V_Five) And
And smaller than the threshold (+ V_Two-V_Five) Is applied.
In the non-selection period, the positive peak value is (+ V₁+ V_Five)
And the negative peak value is (−V_Four+ V_Five) AC pulse and positive wave
High value is (+ V₁-V_Five) And the negative peak value is (−V_Four−
V_Five) AC pulse is t₁₄Are applied alternately at intervals of
You. Peak value of positive and negative pulses applied during the selection period
Difference between on and off (V_Three-V_Two)
The difference is due to the AC pulse applied during the non-selection period.
Of the voltage pulse applied to the liquid crystal element
The value is zero. Also in this comparative example, the memory of the liquid crystal element was used.
-Comparative example12Excellent contra as well as
The strike ratio was obtained. FIG. 43 shows the driving waveforms shown in FIG.
It is a circuit block diagram of an example of the specific circuit which appears. ,
Signal selects transmission gate 111.
Select the scan electrode waveform at the time of
Select the scan electrode waveform when not selected and scan electrode waveform
make. On the other hand, the signal electrode waveform
With the signal electrode data of selecting
Select the ON waveform and the OFF waveform of
And applied to the liquid crystal element 113. V₁, V_Two, -V
_Three, -V_Four, ± V_FiveIs the power supply voltage of the scanning electrode and signal electrode
It is. FIG. 44 is a circuit diagram showing each point of the circuit shown in FIG.
Is the signal at. Comparative Example14 FIG. 45 shows a specific example of realizing the drive waveform in this embodiment.
FIG. 66 is a block diagram showing a typical circuit, and FIG.
Drive to apply the drive waveform created by
FIG. 3 is a diagram illustrating an example of a circuit. 451 is a frame signal, 4
Reference numeral 52 denotes a polarity switching signal.
Switching transmission gate 111 to V
₁, V_Two, -V_Three, -V_FourSwitch the scanning electrode
Is generated. Also, V_Five, -V₆The voltage of
Switching to ON waveform 454 and OFF waveform 4 of the signal electrode
Make 55. FIG. 46 shows the timing of these signal waveforms.
3 shows a chart. The signal waveforms shown in FIG.
Drive wave applied to the scanning path and signal electrode
Make shape. That is, the selection waveform 453 is changed to 8101 and
At 8102, 0V is turned on at 8103 as a non-selection waveform.
Waveform 454 to 8105, Off waveform 455 to 8104
Apply each. In FIG. 66, reference numeral 121 denotes a scanning electrode data.
This is run by the scan electrode shift clock 120.
Transfer to the scan electrode side shift register 115 without one scan electrode
Output the selection signal one by one to
11 is switched, and the scan electrode drive waveform is changed to 8107.
Apply. Reference numeral 117 denotes signal electrode data which is
The electrode electrode shift clock 118 causes the signal electrode
Data for one scanning electrode.
Latched by the latch signal 116 by the latch signal 119
I do. The output of the latch circuit 116 allows the transmission
The switching of the operation gate 111 causes the ON waveform 454
And the off waveform 455 to change the signal electrode drive waveform.
8106. FIG. 46 shows the scanning electrode 81 shown in FIG.
09 and the signal waveform applied to the signal electrode 8110.
The composite waveform applied to element 8111 and the light transmission characteristics are shown.
You. t₁₃, T_{twenty three}, T₃₃And t₄₃Is one frame each
Period, t₁₁, T_{twenty one}, T₃₁And t₄₁Select each
Period, t_{twenty one}, T_{twenty two}, T₃₂And t₄₂Is the non-selection period
Shows the interval. Also t₁₄, T_Fifteen, T_{twenty four}, T_{twenty five}, T₃₄, T₃₅,
t₄₄And t₄₅Indicates the pulse width, in the case of this comparative example
Are all 200 μsec. Also, the peak value V₁And V_FourIs 10V, V
_TwoAnd V_ThreeIs 8V, V_FiveAnd V₆Is 2V. Scan electrode X₁46 shown in FIG.
So that the selection period t₁₁(T_{twenty one}, T₃₁, T₄₁) Is 1 frame
+ V as the first selected waveform alternately for each_Twoand
-V_FourAre in the order of negative and positive, and + V as the second selected waveform.
₁And -V_ThreeAre applied in the order of positive and negative, and the non-selection period t
₁₂(T_{twenty two}, T₃₂, T₄₂), 0V is applied. Also,
Signal electrode Y₁As shown in FIG.
10V to turn on_FiveAnd -V₆Is positive, then negative
+ V to turn off_FiveAnd -V₆Is negative, positive
It is applied in order. At this time, the pixel (X₁Y₁The composition applied to
The waveform shows the scan electrode X as shown in FIG.₁To
On in the frame to which the first selected waveform is applied
Is (-V_Four-V_Five) And (V_Two+ V₆) Is negative, positive
In the case of off, (−V_Four+ V₆) And (V_Two−
V_Five) Is applied in the order of negative and positive, and the second selected waveform is applied
(V)₁-V_Five) And
And (-V_Three+ V₆) Are positive and negative in the order of (V
₁+ V₆) And (−V_Three-V_Five) Is applied in the order of positive and negative
Is done. The non-selection period is -V_FiveAnd + V₆Is applied
It is. The driving method of this comparative example is performed at the beginning of the selection period.
Apply a pulse that is greater than the positive or negative saturation value to turn on or
Turn off, and apply the next pulse to the opposite polarity saturation value or less.
Invert the on / off state as the upper pulse or reverse
As a pulse smaller than the threshold
Ruka is on or off. Also, the first selected wave
Positive and negative pulses in the frame where the shape was applied
Difference between the peak value and (V_Four-V_Two) That is, -2V
However, in the frame to which the second selection waveform is applied,
(V₁-V_ThreeThat is, 12V
be killed. That is, in this comparative example, the image is displayed every two frames.
Liquid crystal element with the average value of the voltage pulse applied to the element set to zero
Is prevented from being deteriorated. Note that the pixel 8111
46 is shown in FIG. Comparative ExampleFifteen FIG. 47 shows a specific example for realizing the drive waveform in this comparative example.
FIG. 66 is a block diagram showing a typical circuit, and FIG.
Drive to apply the drive waveform created by
FIG. 3 is a diagram illustrating an example of a circuit. 471 is a frame signal, 4
Numeral 72 is a polarity switching signal.
Switching transmission gate 111 to V
₁, -V_Two, -V₇, -V₈Switch the voltage of
Create a pole selection waveform 473, -V_Three, -V₆Turn off the voltage
In other words, a non-selection waveform 474 of the scanning electrode is generated. Also,-
V_Two, -V_Four, -V_Five, -V₇Switch the voltage of the
An ON waveform 475 and an OFF waveform 476 of the electrode are created. No.
FIG. 48 shows a timing chart of these signal waveforms.
You. The signal waveforms shown in FIG.
Drive wave applied to the scanning path and signal electrode
Make shape. That is, the selection waveform 473 is changed to 8101 and
8102, unselected waveform 474 to 8103, ON waveform
475 to 8105, OFF waveform 476 to 8104
Each is applied. In FIG. 66, reference numeral 121 denotes a scanning electrode data.
This is scanned by the scan electrode shift clock 120
The data is transferred to the electrode-side shift register 115, and one scanning electrode at a time.
The transmission gate 11 outputs the selection signal sequentially.
1 is switched, and the scan electrode driving waveform is marked on 8107.
Add. Reference numeral 117 denotes signal electrode data which is
The shift register 118 on the signal electrode side
Data for one scanning electrode.
Latched by the latch circuit 116 in accordance with the latch signal 119.
You. The output of the latch circuit 116 causes the transmission
The switching of the gate 111 causes the ON waveform 475 and
And the off waveform 476 to switch the signal electrode drive waveform to 8
106. FIG. 49 shows the scanning electrode 81 shown in FIG.
09 and the signal waveform applied to the signal electrode 8110.
The composite waveform applied to element 8111 and the light transmission characteristics are shown.
You. t₁₃, T_{twenty three}, T₃₃And t₄₃Is one frame each
Period, t₁₁, T_{twenty one}, T₃₁And t₄₁Select each
Period, t₁₂, T_{twenty two}, T₃₂And t₄₂Is the non-selection period
Shows the interval. Also t₁₄, T_Fifteen, T_{twenty four}, T_{twenty five}, T₃₄, T₃₅,
t₄₄And t₄₅Indicates the pulse width. In the case of this comparative example,
Both are 200 μsec. Peak value V₁Is 0V, V_TwoIs 2V, V_ThreeIs 4
V, V_FourIs 6V, V_FiveIs 8V, V₆Is 10V, V₇Is 1
2V, V₈Is 14V. Also, -Vm is applied to the signal electrode.
Indicates the intermediate potential of the applied voltage pulse, in this case -7
V. Comparative Example14The difference is that it is applied to the scanning electrode.
In order to reduce the applied voltage, the voltage of the scan electrode and signal electrode
Common level and signal electrode on / off
At the point where the waveform is changed by the selected waveform applied to the scanning electrode
is there. That is, the scanning electrode 8109 has the structure shown in FIG.
491, the selection period t₁₁(T_{twenty one}, T₃₁,
t₄₁) Alternately with the first selected waveform every frame
And -V₈And -V_TwoIs -V₈, -V_TwoIn the order
V as the second selected waveform₁And -V₇Is V₁, -V₇
, And the non-selection period t₁₂(T_{twenty two}, T₃₂, T₄₂)
Is -V in the frame to which the first selected waveform is applied._ThreeYou
And -V₆Is -V_Three, -V₆, And the second selected wave
-V in the frame to which the shape is applied₆, -V_ThreeApply in order
Is done. The signal electrode 8110 has the structure shown in FIG.
As shown, in the frame to which the first selection waveform is applied,
Is -V as the ON waveform._TwoAnd -V₇Is -V_Two, -V
₇And the off waveform is -V_FourAnd -V_Five
Is -V_Four, -V_FiveAre applied in this order. Also the second selection wave
In the frame to which the shape is applied, the ON waveform is -V_FourYou
And -V_FiveIs -V_Five, -V_FourApplied in the order of
As -V_TwoAnd -V₇Is -V₇, -V_TwoApply in order
Is done. At this time, the composite waveform applied to the pixel 8111
Is, as shown in FIG. 49, the first selection for the scanning electrode.
In the frame to which the selection waveform is applied, when the frame is on, (−V
₈+ V_Two) And (−V_Two+ V₇) Is negative, then positive
(-V₈+ V_Four) And (−V_Two+ V_Five)But
Negative and positive are applied in that order, and the second selection waveform is applied.
In the frame, if on, (V₁Ten volts_Five) And (−V
₇Ten volts_Four) Are positive and negative in the order of (V₁+
V₇) And (−V₈+ V_Two) Are applied in positive and negative order
You. The non-selection period is (−V₆+ V₇) And (−V
_Three+ V_Two) Or (-V_ThreeTen volts_Four) And (−V₆Ten
V_Five) Is applied. The driving method of this comparative example also has
Apply a pulse that is greater than the positive or negative saturation value to turn on or
Turn off, and apply the next pulse to the opposite polarity saturation value or less.
Invert the on / off state as the upper pulse or reverse
As a pulse smaller than the threshold
Ruka is on or off. Also, the first selected wave
Positive and negative pulses in the frame where the shape was applied
Difference between the peak value and (V₇-V₈) Or (V_Four+ V_Five
-V_Two-V₈), That is, -2V, but the second
In the frame to which the selected waveform is applied, V_TwoOr (V
_Four+ V_Five-V₇That is, 12V
Offset. That is, also in this comparative example, every two frames
The average value of the voltage pulse applied to the pixel is
This prevents deterioration of the child. Note that the pixel 811
The light transmission characteristics of No. 1 are shown in FIG. Comparative Example16 FIG. 50 shows a specific example of realizing the driving waveform in the comparative example.
FIG. 66 is a block diagram showing a typical circuit, and FIG.
Drive to apply the drive waveform created by
FIG. 3 is a diagram illustrating an example of a circuit. Reference numeral 501 denotes a frame signal, and 502 denotes a polarity switch.
These signals are used for transmission.
Switching the gate 111₁, V_Two, -V
_Three, -V_FourAre switched, and the selection waveform 50 of the scanning electrode is changed.
Make 3. Also, V_Five, -V₆, Switch the voltage of 0V
To create an ON waveform 504 and an OFF waveform 505 of the signal electrode.
You. FIG. 51 shows the timing chart of these signal waveforms.
Show The signal waveforms shown in FIG.
Drive wave applied to the scanning path and signal electrode
Make shape. That is, the selection waveform 503 is changed to 8101 and
At 8102, 0V is turned on at 8103 as a non-selection waveform.
Waveform 504 to 8105, Off waveform 505 to 8104
Apply each. In FIG. 66, reference numeral 121 denotes scanning electrode data.
This is run by the scan electrode shift clock 120.
Transfer to the scan electrode side shift register 115 without one scan electrode
Output the selection signal one by one to
11 is switched, and the scan electrode drive waveform is changed to 8107.
Apply. Reference numeral 117 denotes signal electrode data which is
The electrode electrode shift clock 118 causes the signal electrode
Data for one scanning electrode.
Latched by the latch signal 116 by the latch signal 119
I do. The output of the latch circuit 116 allows the transmission
The switching of the operation gate 111 is performed, and the ON waveform 504 is output.
And the OFF waveform 505 to switch the signal electrode drive waveform.
8106. FIG. 51 shows the scanning electrode 81 shown in FIG.
09 and the signal waveform applied to the signal electrode 8110.
The composite waveform applied to element 8111 and the light transmission characteristics are shown.
You. t₁₃, T_{twenty three}, T₃₃And t₄₃1 frame around each
Period, t₁₁, T_{twenty one}, T₃₁And t₄₁Is the selection period
Interval, t₁₂, T_{twenty two}, T₃₂And t₄₂Is the non-selection period
Is shown. Also, t₁₄, T_Fifteen, T_{twenty four}, T_{twenty five}, T₃₄, T₃₅,
t₄₄And t₄₅Indicates the pulse width, in the case of this comparative example
Are all 200 μsec. Peak value V₁And V_FourIs 8V, V_Twoand
V_ThreeIs 6V, V_FiveAnd V₆Is 2V. The scanning electrode 8109 has the structure shown in FIG.
As shown, the selection period t₁₁(T_{twenty one}, T₃₁, T₄₁) Is 1
Alternately for each frame, V_TwoAnd
And -V_FourAre in the order of negative and positive, and V
₁And -V_ThreeAre applied in the order of positive and negative, and the non-selection period t
₁₂(T_{twenty two}, T₃₂, T₄₂), 0V is applied. The signal electrode 8110 has the structure shown in FIG.
As shown, in the frame to which the first selection waveform is applied,
Is V_FiveAnd -V₆Is positive, then negative
0V is applied as an off waveform. The frame to which the second selection waveform is applied is
0V is applied as the ON waveform and the OFF waveform
V_FiveAnd -V₆Are applied in the order of negative and positive. At this time, the composite waveform applied to the pixel 8111
Is the first selection for the scanning electrode as shown in FIG.
In the frame to which the selection waveform is applied, when the frame is on, (−V
_Four-V_Five) And (V_Two+ V₆) Turns off in the order of negative, positive
-V for_FourAnd V_TwoAre applied in the order of negative and positive.
In the frame to which the selected waveform 2 is applied,
V₁And -V_ThreeAre positive and negative in the order of (V₁
+ V₆) And (−V_Three-V_Five) Are applied in the order of positive and negative
It is. In the non-selection period, 0 V or V_FiveAnd
And -V₆Is applied. The driving method of this comparative example also has
Apply a pulse that is greater than the positive or negative saturation value to turn on or
Turn off, and apply the next pulse to the opposite polarity saturation value or less.
Invert the on / off state as the upper pulse or reverse
As a pulse smaller than the threshold
Ruka is on or off. Also, the first selected wave
Positive and negative pulses in the frame where the shape was applied
Difference between the peak value and (V_Two-V_Four) That is, -2V
However, in the frame to which the second selection waveform is applied,
(V₁-V_Three) That is, it is + 2V,
be killed. That is, in this comparative example, an image is displayed every two frames.
Liquid crystal element with the average value of the voltage pulse applied to the element set to zero
Is prevented from being deteriorated. Note that the pixel 8111
51 is shown in FIG. Comparative Example17 FIG. 52 shows a specific example for realizing the drive waveform in this comparative example.
FIG. 66 is a block diagram showing a typical circuit, and FIG.
Drive to apply the drive waveform created by
FIG. 3 is a diagram illustrating an example of a circuit. 521 is a frame signal, 5
Reference numeral 22 denotes a polarity switching signal.
Switch transmission gate 111 to V
₁, -V_Two, -V₇, -V₈Switch the voltage of
Create a pole selection waveform 523, and_Three, -V₆Turn off the voltage
In other words, a non-selection waveform 524 of the scanning electrode is generated. Also,-
V_Two, -V_Three, -V₆, -V₇Switch the voltage of the
An ON waveform 525 and an OFF waveform 526 for the electrode are created. No.
FIG. 53 shows a timing chart of these signal waveforms.
You. The signal waveforms shown in FIG.
Drive wave applied to the scanning path and signal electrode
Make shape. That is, the selection waveform 523 is changed to 8101 and
8102, unselected waveform 524 to 8103, ON waveform
525 to 8105, OFF waveform 526 to 8104
Each is applied. In FIG. 66, reference numeral 121 denotes scanning electrode data.
This is scanned by the scan electrode shift clock 120
The data is transferred to the electrode-side shift register 115, and one scanning electrode at a time.
The transmission gate 11 outputs the selection signal sequentially.
1 is switched, and the scan electrode driving waveform is marked on 8107.
Add. Reference numeral 117 denotes a signal electrode data, which is connected to a signal electrode.
The shift register 118 on the signal electrode side
Data for one scanning electrode.
Latched by the latch circuit 116 in accordance with the latch signal 119.
You. The output of the latch circuit 116 causes the transmission
The switching of the gate 111 causes the ON waveform 525 and the
And the off waveform 526 to change the signal electrode drive waveform to 8
106. FIG. 54 shows the scanning electrode 81 shown in FIG.
09 and a drive waveform applied to the signal electrode 8110;
The combined waveform and light transmission characteristics applied to the pixel 8111
Show. T₁₃, T_{twenty three}, T₃₃And t₄₃Respectively
One frame period, t₁₁, T_{twenty one}, T₃₁And t₄₁Is it
Each selection period, t₁₂, T_{twenty two}, T₃₃And t₄₂Are each
Indicates a non-selection period. Also t₁₄, T_Fifteen, T_{twenty four}, T_{twenty five},
t₃₄, T₃₅, T₄₄And t₄₅Indicates the pulse width.
In the case of the comparative examples, it is 200 μsec in each case. Peak value V₁Is 0V, V_TwoIs 2V, V_ThreeIs 4
V, V₆Is 8V, V₇Is 10V, V₈Is 12V.
Vm is the intermediate voltage of the voltage pulse applied to the signal electrode.
Position, in this case 6V. Comparative Example16The difference is that it is applied to the scanning electrode.
In order to reduce the applied voltage, the voltage of the scan electrode and signal electrode
The level is common. The scanning electrode 8109 has the structure shown in FIG.
As shown, the selection period t₁₁(T_{twenty one}, T₃₁, T₄₁) Is 1
Alternately for each frame, the first selected waveform is -V₈You
And -V_TwoIs -V₈, -V_Two, And the second selected wave
V as shape₁And -V₇Is V₁, -V₇Applied in the order
And the non-selection period t₁₂(T_{twenty two}, T₃₂, T₄₂) Is the first selection
-V in the frame to which the selective waveform is applied_ThreeAnd -V₆But
-V_Three, -V₆And the second selected waveform is
-V in the applied frame₆, -V_ThreeApplied in the order
You. The signal electrode 8110 has the structure shown in FIG.
As shown, in the frame to which the first selection waveform is applied,
Is -V as the ON waveform._TwoAnd -V₇Is -V_Two, -V
₇In the order of -V_ThreeAnd -V₆But-
V_Three, -V₆, And the second selection waveform is marked
In the added frame, the ON waveform is -V_ThreeAnd-
V₆Is -V₆, -V_ThreeIn the order of -V_TwoYou
And -V₇Is -V₇, -V_TwoAre applied in this order. At this time, a composite waveform applied to pixel 8111
Is the first selection for the scanning electrode as shown in FIG.
In the frame to which the selection waveform is applied, when the frame is on, (−V
₈+ V_Two) And (−V_Two+ V₇) Is negative, then positive
(-V₈+ V_Three) And (−V_Two+ V₆)
Were applied in the order of negative and positive, and the second selected waveform was applied
In the frame, if it is on (-V_Two+ V₇)and
(-V₇+ V_Three) Are positive and negative in the order of (V₁
+ V₇) And (−V₇+ V_Two) Are applied in the order of positive and negative
It is. In the non-selection period, 0 V or (−V₆
+ V₇) And (−V_Three+ V_Two) Is applied. The driving method of this comparative example also has a
Apply a pulse that is greater than the positive or negative saturation value to turn on or
Turn off, and apply the next pulse to the opposite polarity saturation value or less.
Invert the on / off state as the upper pulse or reverse
As a pulse smaller than the threshold
Ruka is on or off. Also, the first selected wave
Positive and negative pulses in the frame where the shape was applied
Difference between the peak value and (V₇-V₈) Or (V₆−
V₇), That is, −2 V, but the second selected waveform
Is applied to the frame to which (V_Three-V_Two) Or V
_TwoThat is, they are +2 V and are offset each other. You
That is, in this comparative example, the voltage is applied to the pixel every two frames.
The average value of the voltage pulse to zero to prevent deterioration of the liquid crystal element
Is what you are doing. Note that the light transmission characteristics of the pixel 8111
Is shown in FIG. 54 544. Comparative Example18 FIG. 55 shows a specific example of realizing the drive waveform in this comparative example.
FIG. 66 is a block diagram showing a typical circuit, and FIG.
Drive to apply the drive waveform created by
FIG. 3 is a diagram illustrating an example of a circuit. 551 is a frame signal, 5
52 is a polarity switching signal, 553 is a write pulse cutoff
These signals are used for transmission.
Switching the gate 111₁, V_Two,
V_Three, -V_Four, -V_Five, -V₆Switch voltage and scan
An electrode selection waveform 554 is created. Also, V₇, -V₈, 0
By switching the voltage of V, the ON waveform 555 of the signal electrode and
An off waveform 556 is created. FIG. 56 shows these signal waveforms.
3 shows a timing chart. These signal waveforms are referred to as the sixth
6 is applied to the driving circuit shown in FIG.
Create a drive waveform to be applied to That is, the selection waveform 554
To 8101 and 8102, and OV as the unselected waveform
8103, ON waveform 555 to 8105, OFF waveform 5
56 is applied to 8104 respectively. In FIG. 66, reference numeral 121 denotes scanning electrode data.
This is run by the scan electrode shift clock 120.
Transfer to the scan electrode side shift register 115 without one scan electrode
Output the selection signal one by one to
11 is switched, and the scan electrode drive waveform is changed to 8107.
Apply. Reference numeral 117 denotes signal electrode data which is
The electrode electrode shift clock 118 causes the signal electrode
Data for one scanning electrode.
Latched by the latch signal 116 by the latch signal 119
I do. The output of the latch circuit 116 allows the transmission
Switching the gate 111, the ON waveform 555
And the OFF waveform 556 to switch the signal electrode drive waveform.
8106. FIG. 56 shows the scanning electrode 81 shown in FIG.
09 and a drive waveform applied to the signal electrode 8110;
The combined waveform and light transmission characteristics applied to the pixel 8111
Show. T₁₃, T_{twenty three}, T₃₃, And t₄₃Each
1 frame period, t₁₁, T_{twenty one}, T₃₁And t₄₁Is
Each selection period, t₁₂, T_{twenty two}, T₃₂And t₄₂Is that
Indicates a non-selection period. Also t₁₄, T_Fifteen, T_{twenty four}, T_{twenty five}, T
₃₄, T₃₅, T₄₄And t₄₅Indicates the pulse width.
In the case of the example, each is 200 μsec. Also, calligraphy
The pulse width of the write pulse switching signal (hereinafter referred to as t / 4)
) Is 1/4 of the pulse width, that is, 50 μsec.
is there. Peak value V₁And V_FourIs 9V, V_Twoand
V_FiveIs 6V, V_ThreeAnd V₆Is 11V, V₇And V₈
Is 3V. In this comparative example, the driving waveform
The switching signal is superimposed and applied to the pixels during the non-selection period.
Effect on light transmission characteristics by reducing the pulse width of the applied pulse
Is smaller. The scanning electrode 8109 has the structure shown in FIG.
As shown, the selection period t₁₁(T_{twenty one}, T₃₁, T₄₁) Is 1
Alternately for each frame, the first selected waveform is -V₆You
And V_TwoOn which a write pulse switching signal is superimposed
Vs as the second selected waveform in the order of negative and positive₁and
-V_FiveTo which the write pulse switching signal is superimposed
Are applied in the order of positive and negative, and the non-selection period t₁₂(T_{twenty two}, T
₃₂, T₄₂) Is applied with 0V. The signal electrode 8110 has the structure shown in FIG.
As shown, as the ON waveform, first, at a pulse width of t / 4,
0V and V₇Are applied alternately two by two, and then the same
-V in loose width₈And 0V are applied alternately by two
You. Also, a pulse having the opposite phase to the ON waveform is printed as the OFF waveform.
Be added. At this time, a composite waveform applied to pixel 8111
Is, as shown in FIG. 56, the first selection for the scanning electrodes.
In the frame to which the selection waveform is applied, -V₆To
Part-V₇And (V_TwoTen volts₈) =
V₁Is applied and -V when off₆Part V₈Is superimposed
Pulse and (V₁-V₇) = V_TwoIs applied.
In the frame to which the second selection waveform is applied,
Case V_ThreePart -V₇And (−V
_FourTen volts₈) = − V_FiveIs applied, and when off, V_ThreeNiichi
Part V₈And (−V_Five-V₇) = −
V_FourIs applied. During the non-selection period, 0 V, V₇And -V₈But
It is applied with a pulse width of t / 4. In this comparative example, the voltage is applied at the beginning of the selection period.
V_ThreeOr -V₆± V₇Or ± V₈But heavy
Since all folded pulses are above the saturation value,
The element is turned on or off once and then applied
The pulse with the opposite polarity to the first pulse exceeds the saturation value.
Depending on the value, the on / off state is reversed or
On or off is selected depending on whether to keep it as it is. Ma
In a frame to which the first selected waveform is applied, a positive
Difference between the positive pulse and the negative pulse is (−V₆+ V₇/ 2-V₁)
= (V₆-V₈/ 2-V_Two), That is, -3.5 V
But in the frame where the second selected waveform is applied
Is (V_Three-V₇/ 2-V_Five) = (V_Three+ V₈/ 2-V
_Four), Ie, 133.5 V, and are mutually offset. You
That is, also in this embodiment, the voltage is applied to the pixel every two frames.
The average value of the voltage pulse to zero to prevent deterioration of the liquid crystal element
Is what you are doing. Note that the light transmission characteristics of the pixel 8111
Is shown in FIG. In this comparative example, the pattern superimposed on the driving waveform is
The pulse width of the pulse is t / 4, but the present invention is not limited to this.
The pulse width is smaller than that of the superimposed pulse.
May be increased. Comparative Example19 FIG. 57 shows a specific example for realizing the drive waveform in this comparative example.
FIG. 66 is a block diagram showing a typical circuit, and FIG.
Drive to apply the drive waveform created by
FIG. 3 is a diagram illustrating an example of a circuit. 571 is a frame signal, 5
72 is a polarity switching signal, 573 is a write pulse switch
These signals are used for transmission.
Switching the gate 111₁, -V_Two, −
V_Three, -V₆, -V₇, -V₈Switch voltage and scan
An electrode selection waveform 574 is created, and -V_Three, -V₆The voltage of
By switching, a non-selection waveform 575 of the scanning electrode is generated. Also,
-V_Two, -V_Three, -V_Four, -V₆, -V₇Turn off the voltage
Instead, the ON waveform 576 and the OFF waveform 577 of the signal electrode
make. FIG. 58 shows the timing chart of these signal waveforms.
Indicates a yat. The signal waveforms shown in FIG.
Drive wave applied to the scanning path and signal electrode
Make shape. That is, the selection waveform 574 is changed to 8101 and
8102, unselected waveform 575 to 8103, ON waveform
576 to 8105, OFF waveform 577 to 8104
Each is applied. Referring to FIG. 66, reference numeral 121 denotes scan electrode data.
This is scanned by the scanning electrode soft clock 120.
The data is transferred to the electrode-side shift register 115, and one scanning electrode at a time.
The transmission gate 11 outputs the selection signal sequentially.
1 is switched and the scan electrode drive waveform is marked on 8607.
Add. Reference numeral 117 denotes signal electrode data which is
The shift register 118 on the signal electrode side
Data for one scanning electrode.
Latched by the latch circuit 116 in accordance with the latch signal 119.
You. The output of the latch circuit 116 causes the transmission
The switching of the gate 111 causes the ON waveform 576 and the
And the off waveform 577 to change the signal electrode drive waveform to 8
106. FIG. 59 shows a scanning electrode 81 shown in FIG.
09 and the signal waveform applied to the signal electrode 8110.
The composite waveform applied to element 8111 and the light transmission characteristics are shown.
You. t₁₃, T_{twenty three}, T₃₃And t₄₃Is one frame each
Period, t₁₁, T_{twenty one}, T₃₁And t₄₁Select each
Period, t₁₂, T_{twenty two}, T₃₂And t₄₂Are not selected
Indicates the period. Also t₁₄, T_Fifteen, T_{twenty four}, T_{twenty five}, T₃₄, T₄₄
And t₄₅Indicates the pulse width, and in this comparative example,
The deviation is also 200 μsec. Write pulse off
The pulse width of the switching signal (hereinafter referred to as t / 4) is
It is ４ of the loose width, that is, 50 μsec. Peak value V₁Is 0V, V_TwoIs 2V, V_ThreeIs 4
V, V_FourIs 6V, V_FiveIs 8V, V₆Is 10V, V₇Is 1
2V, V₈Is 14V, and Vm is applied to the signal electrode.
In this case, it is 7V. Comparative Example18The difference is that it is applied to the scanning electrode.
In order to reduce the applied voltage,
Combined pressure level and selectable ON / OFF waveform
That is, according to the shape. The scanning electrode 8109 has the structure shown in FIG.
As shown, the selection period t₁₁, (T_{twenty one}, T₃₁, T₄₁)
Alternately every frame, the first selected waveform is -V₈
And -V_ThreeThe write pulse switching signal is superimposed on
Pulse as the second selected waveform₁And -V₇To
Apply pulse with write pulse switching signal superimposed
And the non-selection period t₁₂(T_{twenty two}, T₃₂, T₄₂) Is -V_ThreeYou
And -V₆Is -V_Three, -V₆Or -V₆, −
V_ThreeAre applied in this order. The signal electrode 8110 has the structure shown in FIG.
As shown, in the frame to which the first selection waveform is applied,
Is -V as the ON waveform._TwoAnd -V_ThreeIs a t / 4 pal
After the two pulses are applied alternately with the same pulse width, with the same pulse width,
-V₇And -V₆Are applied alternately two by two, and the off-wave
-V with the same pulse width as the shape_ThreeAnd -V_FourAlternately
After being applied two by two, -V₆And -V_FiveBut the same pal
Are applied alternately at intervals of two lines. The frame to which the second selection waveform is applied
In this example, the ON waveform is a pulse with the opposite phase to the OFF waveform.
Is applied, and the off waveform has a phase opposite to that of the on waveform.
A pulse is applied. At this time, a composite waveform applied to pixel 8111
Is the first selection for the scanning electrodes as shown in FIG.
In the frame to which the select waveform is applied, when the switch is on (−V₈
+ V_Three) Partially (V_Two-V_Three) Superimposed pulses and
And (-V_Three+ V₇) = (− V_Two+ V₆) Is applied and
(-V₈+ V_Four) Partially (V_Three-V_Four) Is superimposed
Pulse and (−V_Three+ V₆) = (− V_Two+
V_Five) Is applied. Also, the second selection waveform was applied.
In the frame, if it is on (V₁+ V₆) Partially (V_Five
-V₆) And (−V₆Ten volts_Three) =
(-V₇Ten volts_Four) Is applied and off (V₁Ten
V₇) Partially (V₆-V₇) Superimposed pulses and
(-V₆+ V_Two) = (− V₇+ V_Three) Is applied. The non-selection period is OV, (-V₆+ V₇)
And (-V_Three+ V_Two) Is applied with a pulse width of t / 4
You. The voltage applied to the pixel by the driving method of this comparative example is
The synthesized waveform is basically a comparative example18Is the same as
In the frame to which the selected waveform 1 is applied, a positive pulse and
The difference from the negative pulse is (V₈-V_Two/ 2-V_Three/ 2-V₆
+ V_Two) = (V₈-V_Three/ 2-V_Four/ 2-V_Five+ V_Two)
That is, -3 V, the frame to which the second selection waveform is applied.
Then, (V₆/ 20V₇/ 2 + V_Three-V₇) = (V_Five/
2 + V₆/ 2 + V_Four-V₇) That is, each other at 13V
Are killed, and the average becomes zero every two frames
You. The light transmission characteristics of the pixel 8111 are shown in FIG.
You. In the examples and comparative examples described so far,
Is the threshold characteristic of the ferroelectric liquid crystal TDOBAMBCC.
Each voltage level was set accordingly, but of course the present invention
It is not limited to this, and each voltage level is used.
Appropriate value according to the threshold characteristics of ferroelectric liquid crystal
Just do it. Comparative Example20 FIGS. 67 (a) and (b) show waveforms of applied voltage pulses.
FIG. 5 is a diagram showing a relationship between the light transmission characteristic and the light transmission characteristic. Ferroelectric liquid crystal
Threshold and saturation voltages vary with pulse width
As mentioned earlier, we also depend on the applied pulse
Found to change. That is, at 824 in FIG.
As shown by the solid line, the wave as shown at 821 in FIG.
When a pulse of a positive shape is applied, the positive and negative threshold
₁₁And Vth₁₂, The saturation value is Vsat₁₁And Vsat
₁₂But a pulse as shown in FIG. 67 (b) 822.
Is applied, a dotted line is shown in FIG. 67 (a) 825.
Thus, the positive and negative thresholds are Vth_{twenty one}And Vth_{twenty two}, Saturated
Value is Vsat_{twenty one}And Vsat_{twenty two}And 821 waveform
The absolute value is larger than when
When a pulse having a waveform is applied, a dot-dash line is shown at 826.
As shown in FIG.₁And Vth_Two, Boring
Sum value is Vsat₁And Vsat_TwoAnd the absolute value is small
You. In particular, Vth_{twenty one}> Vsat₁₁And | Vt
h_{twenty two}|> | Vsat₁₂|, The waveform 821
At the voltage level above the saturation value when applying
However, when a pulse having a waveform of 822 is applied,
And the liquid crystal element does not respond. But
Control the response and non-response at the same voltage level.
It becomes possible. This comparative example shows the use of such a ferroelectric liquid crystal.
This is a driving method using a threshold value characteristic. FIG. 60 shows a driving waveform in this comparative example.
FIG. 66 is a block diagram showing a specific circuit to be realized, and FIG.
Applies the drive waveform generated by this circuit to the liquid crystal element.
FIG. 2 is a diagram showing an example of a driving circuit for performing the above. 601 is free
602 is a polarity switching signal.
The transmission gate 111 is switched by a signal.
Ching and V₁, V_Two, -V_Three, -V_FourSwitch the voltage of
First, a scan electrode selection waveform 604 is generated. Polarity switching
Signal 602 and the clock pulse 603, 0V,
V_Five, -V_FiveOf the signal electrode to change the voltage of
05 and off waveform 606. Figure 61 shows these
3 shows a timing chart of the signal waveform of FIG. The signal waveforms shown in FIG.
Drive wave applied to the scanning path and signal electrode
Make shape. That is, the selection waveform 604 is changed to 8101 and
At 8102, 0V is turned on at 8103 as a non-selection waveform.
Waveform 605 to 8105, OFF waveform 606 to 8104
Apply each. Referring to FIG. 66, reference numeral 121 denotes a scanning electrode data.
This is run by the scan electrode shift clock 120.
Transfer to the scan electrode side shift register 115 without one scan electrode
Output the selection signal one by one to
11 is switched, and the scan electrode drive waveform is changed to 8107.
Apply. Reference numeral 117 denotes signal electrode data which is
The electrode electrode shift clock 118 causes the signal electrode
Data for one scanning electrode.
Latched by the latch signal 116 by the latch signal 119
I do. The output of the latch circuit 116 allows the transmission
Switch on the ON gate 605
And the OFF waveform 606 to switch the signal electrode drive waveform.
8106. FIG. 62 shows the scanning electrode 81 shown in FIG.
09 and the signal waveform applied to the signal electrode 8110.
The composite waveform applied to element 8111 and the light transmission characteristics are shown.
You. t₁₃, T_{twenty three}, T₃₃And t₄₃Is one frame each
Period, t₁₁, T_{twenty one}, T₃₁And t₄₁Select each
Period, t₁₂, T_{twenty two}, T₃₂And t₄₂Are not selected
Indicates the period. Also t₁₄, T_{twenty four}, T₃₄And t₄₄Is it
The pulse width of the pulse applied in the first half of the selection period, t
_Fifteen, T_{twenty five}, T₃₅And t₄₅Is the second half of the selection period
Indicates the pulse width of the pulse applied to
Have the same pulse width. Further t₀
Is the t_Fifteen(T_{twenty five}, T₃₅, T₄₅) 1/2 pulse width
Is shown. Crest value V₁~ V_FiveSatisfies the following conditions
Set to [0207] V₁= V_Four> Vsat₁, | Vsat_Two| V_Five<Vth₁, | Vth_Two| ｜ V_Two| = | −V_Three| Vth_{twenty one}> (V_Two+ V_Five)> Vsat₁₁ | Vth_{twenty two}|> (V_Three+ V_Five)> | Vsat₁₂| As shown in FIG. 62, the scanning electrode 8109 has
The selection period is -V as the first selection waveform._FourAnd V_TwoBut
In the order of negative and positive, V₁And -V_Three
Are applied alternately for each frame in the order of positive and negative,
OV is applied during the selection period. The signal electrode 8110 has the structure shown in FIG.
As shown, if you want to turn on, 2t₀0V mark during period
Pulse width t after applied₀V_FiveAnd -V_FiveIs positive / negative
It is applied in order, and if you want to turn it off,₀Period of
Pulse width t after 0V is applied₀V_FiveAnd -V_FiveBut
It is applied in the order of negative and positive. At this time, the composite waveform applied to the pixel 8111
Is the first selection for the scanning electrode as shown in FIG.
In the frame to which the selective waveform is applied, first, when turned on, -V
_FourIs applied, the first half of t₀Peak value of (V_Two−
V_Five) In the latter half of t₀Peak value of (V_Two+ V_Five)
Is applied, and in the case of off, first -V_FourIs applied
The first half of t₀Peak value of (V_TwoTen volts_Five) In the second half
T₀Peak value of (V_Two-V_Five) Is a pulse applied
It is. In the frame to which the second selection waveform is applied,
If on, first V₁Is applied, the first half of t₀Wave height
If the value is (-V_Three-V_Five) In the latter half of t₀Crest value is (−V_Three
+ V_Five) Is applied, and when it is off,
First V₁Is applied, the first half of t₀Crest value is (−V
_Three+ V_Five) In the latter half of t₀Crest value is (−V_Three-V_Five)so
A certain pulse is applied. During the non-selection period, 0V and
Loose width t₀± V_FiveIs applied. In this comparative example, FIG. 67 (a) and FIG.
As shown in (b), the selection period t₁₁And t_{twenty one}Second half of
Are above the saturation value, but t₃₁And
And t₄₁Pulses applied in the second half of the
The threshold value
It is a smaller value. As a result, the driving method of this comparative example
Method also applies the positive or negative saturation value applied at the beginning of the selection period
The pulse is turned on or off by the above pulse.
Whether the state is reversed by a pulse of opposite polarity applied
Select whether to keep it as it is and select ON / OFF.
Can be. Further, the frame to which the first selection waveform is applied is
The difference between the peak values of the positive and negative pulses is
(V_Two+ V_Three) / 2 + (V_Two-V_Five) / 2-V_Four= V_Two
-V_Four, In the frame to which the second selected waveform is applied, (−
V_Three-V_Five) / 20 (-V_Three+ V_Five) / 2 + V₁= V₁
-V_ThreeAnd V₁= V_FourAnd V_Two= V_ThreeIs
Are mutually offset. That is, in this comparative example, two frames
The average value of the voltage pulse applied to the pixel for each
Thus, deterioration of the liquid crystal element can be prevented. In addition,
The light transmission characteristics of the pixel 8111 are shown in FIG. 62, 624. Comparative Example21 This comparative example also has a structure as shown in FIGS. 67 (a) and (b).
This is a driving method using the threshold characteristics of ferroelectric liquid crystal.
You. FIG. 63 shows drive waveforms in this comparative example.
FIG. 66 is a block diagram showing a specific circuit to be realized, and FIG.
Applies the drive waveform generated by this circuit to the liquid crystal element.
FIG. 2 is a diagram showing an example of a driving circuit for performing the above. 631 is free
632 is a polarity switching signal.
The transmission gate 111 is switched by a signal.
Ching and V₁, -V_Two, -V₇, -V₈Turn off the voltage
In response, a selection waveform 634 of the scanning electrode is created, and -V_Three, -V
₆Of the scan electrodes to generate the non-selection waveform 635.
You. Also, the polarity switching signal 632 and the clock pulse 6
33, -V_Two, -V_Three, -V_Four, -V_Five, -V
₆, -V₇And the ON voltage 63 of the signal electrode is switched.
6 and off waveform 637. FIG. 64 shows these
4 shows a timing chart of a signal waveform. The signal waveforms shown in FIG.
Drive wave applied to the scanning path and signal electrode
Make shape. That is, the selection waveform 634 is changed to 8101 and
8102, unselected waveform 635 to 8103, ON waveform
636 to 8105, OFF waveform 637 to 8104
Apply it. Referring to FIG. 66, reference numeral 121 denotes a scanning electrode data.
This is scanned by the scan electrode shift clock 120
Transfer to electrode side shift register 115
A next selection signal is output to transmit the transmission gate 111
Is switched and the scan electrode drive waveform is applied to 8107
I do. Reference numeral 117 denotes signal electrode data, which is a signal electrode data.
The shift register 118 shifts the signal electrode side.
Transfer data to one scan electrode 114 and transfer data for one scan electrode.
Latch is performed by the latch circuit 116 according to the latch signal 119.
You. The output of the latch circuit 116 causes the transmission
The gate 111 is switched to turn on the
And the OFF waveform 637 to change the signal electrode drive waveform to 8
106. FIG. 65 shows the scanning electrode 81 shown in FIG.
09 and a drive waveform applied to the signal electrode 8110;
The combined waveform and light transmission characteristics applied to the pixel 8111
Show. T₁₃, T_{twenty three}, T₃₃And t₄₃Respectively
One frame period, t₁₁, T_{twenty one}, T₃₁And t₄₁Is it
It selection period, t₁₂, T_{twenty two}, T₃₂, And t₄₂Is it
Each indicates a non-selection period. Also t₁₄, T_{twenty four}, T₃₄And t
₄₄Is the pulse pulse applied in the first half of the selection period.
Loose width t_Fifteen, T_{twenty five}, T₃₅And t₄₅Is a selection period
This shows the pulse width of the pulse applied in the latter half of
In the case of the example, all have the same pulse width. Sa
T₀Is the t_Fifteen(T_{twenty five}, T₃₅, T₄₅) Of 1/2
Indicates the pulse width. Comparative Example20The difference is that it is applied to the scanning electrode.
In order to reduce the applied voltage,
Pressure level and the ON waveform and
And the off waveform is changed according to the selected waveform. Peak value V₁~ V₈And Vm are the following conditions
Is set to satisfy. [0220] V₁= 0 (V₁+ V₆)> Vsat₁ (V₈-V_Three)> | Vsat_Two| (V₇-V₆) = (V_Four-V_Three) <Vth₁ (V₆-V_Five) = (V_Three-V_Two) <| Vth_Two| Vth_{twenty one}> (V₇-V_Two)> Vsat₁₁ | Vth_{twenty two}|> (V₇-V_Two)> | Vsat₁₂| (Vm-V_Two) = (V₇-Vm) As shown in FIG. 651, the scanning electrode 8109 has
The selection period is the first selection waveform, and the first half is -V.₈In the second half
-V_TwoHowever, as the second selected waveform, the first half is V₁, The latter half-
V₇Is applied, and the non-selection period is -V.₆And -V_ThreeBut-
V₆, -V_ThreeOr -V_Three, -V₆Applied in the order
It is. The signal electrode 8110 has the structure shown in FIG.
As shown, in the frame to which the first selection waveform is applied,
Is -V first as the ON waveform._ThreeThen the pulse width t₀
-V_FiveAnd -V₇Is -V_Five, -V₇Applied in the order
-V as the off waveform_ThreeAfter -V₇, -V
_FiveAre applied in this order. Also, the second selection waveform was applied.
In the frame, the ON waveform first is -V₆But in the second half
Loose width t₀-V_FourAnd -V_TwoIs -V_TwoOne V_FourIn order
-V as the off waveform₆After-
V_Four, -V_TwoAre applied in this order. At this time, a composite waveform applied to pixel 8111
Is the first selection for the scanning electrodes as shown in FIG. 653.
In the frame to which the selection waveform is applied, if it is on, first (-
V₈+ V_Three) Is applied, the first half of t₀The peak value of
(-V_Two+ V_Five) In the latter half of t₀Crest value is (−V_Two+ V
₇) Is applied, and when it is off,
(-V₈+ V_Three) Is applied, the first half of t₀Wave height
If the value is (-V_TwoTen volts₇) In the latter half of t₀Crest value is (−V_Two
+ V_Five) Is applied. Also the second selection wave
In the frame to which the shape is applied, first, (V₁+
V₆) Is applied, the first half of t₀Crest value is (−V₇
Ten volts_Two) In the latter half of t₀Crest value is (−V₇+ V_Four)
Pulse is applied, and when it is off (V₁+ V₆)
Is applied, the first half of t₀Crest value is (−V₇+
V_Four) In the latter half of t₀Crest value is (−V₇+ V_Two)
A pulse is applied. OV, (−V₆+
V₇) And (−V₆+ V_Five) Is applied. The synthesized waveform according to this comparative example is the same as that of the comparative example.20When
Are essentially the same, with the same on / off selection
And the voltage applied to the pixels every two frames.
The average value of Lus becomes zero. The light transmission of the pixel 8111
The characteristics are shown in FIG. Comparative Example22 This comparative example also has a structure as shown in FIGS. 67 (a) and (b).
This is a driving method using the threshold characteristics of ferroelectric liquid crystal.
You. FIG. 69 shows a driving waveform in this comparative example.
FIG. 69 is a block diagram showing a specific circuit to be realized, and 691 is
A frame signal 692 is a polarity switching signal. This
The transmission gate is controlled by the signals 691 and 692 of
Switch 111 to V₁, -V_Two, −
V₇, -V₈, -V_Three, -V₆Switch the voltage of the odd number
Scan electrode select waveform 694 and even scan electrode select waveform 69
5, and a scan electrode non-selection waveform 696 is generated. Also, 691, 692 and clock pallets
The transmission gate 1
11 is switched to -V2 , -V_Four, -V_Five, −
V₇The voltage of the signal electrode is turned on and the signal
An electrode off waveform 698 is created. A timing chart of these waveforms is shown in FIG.
FIG. Fig. 70 Fig. 694, 695, 696, 69
Each of the waveforms 7 and 698 is input to the drive circuit shown in FIG.
94 is 8101, 695 is 8102, 696 is 81
03, 697 is 8105, 698 is 8105, and so on.
Connect each one. Then, FIG.
71, FIG.
1 odd scan electrode waveform and 712 even scan electrode waveform
And the signal electrode waveform of 713 is created and applied to the liquid crystal element.
You. The composite waveform is shown at 714. Drive of this drive waveform
The conditions are as follows. [0228] V₁= 0 | -V₈+ V_Two|> | Vsat_{twenty two}| (-V_Two+ V₇)> Vsat₁₁        (-V_Two+ V₇) <Vth_{twenty one} (V₁Ten volts₇)> Vsat_{twenty one}          | -V₇+ V_Two|> | Vsat₁₂| | -V₇Ten volts_Two| <| Vth_{twenty two}| (−V_TwoTen volts_Three) <Vth₁ | -V_Four+ V_Three| <| Vth_Two| (−V_Two+ V_Three) = (− V_Five+ V₆) (-V_Four+ V_Three) = (− V₇+ V₆) (-V_Two+ Vm) = (− Vm + V₇) t₁₄= T₁₁ (V₈-V_Three) = (V₆-V₁) (V₆-V_Two) = (V₇-V_Three) Description of the operation of the liquid crystal element for the pixel in FIG.
Then, FIG. 71 t₀₄Apply immediately before the odd frame
The erase electrode pulse 711 and the scan electrode waveform 711
| -V always with composite voltage of signal electrode waveform₈+ V_Two|> | V
sat_{twenty two}Apply the voltage pulse | to the memo in front of the liquid crystal element.
Erases the memory state to the off state, t₁₁Odd odd frame
Waveform applied to the signal electrode during the
Scan electrode waveform depending on the shape or off waveform
822 of FIG. 67 or 822 of FIG.
Select the waveform indicated by, and if the waveform is indicated by 821, select the liquid crystal
The element turns on, and turns off if the waveform shown by 822 occurs.
It remains in the state. In the non-selection period, the scan electrode waveform 71
1 is -V_ThreeAnd -V₆Are applied alternately, and 71
In the composite waveform with the signal electrode waveform of No. 3 as shown by 714
Only the voltage whose absolute value is smaller than the threshold voltage
Is not applied to₁₁Keep state written during
I do. In addition, the selection period t₁₁Write data to the liquid crystal element during
The next time the LCD is selected
A scan electrode waveform 712 is applied to the element.
Therefore, t₀₄Before the erase pulse of the opposite polarity is applied
Is erased and turned on. next,
Looking at even-numbered frames,₁₄Between
Lus, t just before the odd frame₀₄Of the polarity opposite to that of
Lus, (V₁+ V₇)> Vsat_{twenty one}Mark the voltage pulse of
To erase the memory state before the liquid crystal element and turn it on.
And t_{twenty one}Is the selection period, and the wave applied to the signal electrode
Depending on whether the shape is an ON waveform or an OFF waveform,
The composite voltage with the inspection electrode waveform is the waveform indicated by 821 in FIG.
Or 822 and select the waveform
If there is, the liquid crystal element is turned off, and the waveform shown by 822
If there is, it remains on. And during the non-selection period,
T is the same as for odd frames_{twenty one}The state written during
Carry. In addition, the selection period t_{twenty one}Write data to the liquid crystal element during
The next time the LCD is selected
The element has a scanning electrode waveform 712 applied thereto.
, T₁₄The erase pulse of the opposite polarity to that during
The memory state is erased and turned off. like this
At the same time as writing data to the liquid crystal element,
An erase pulse is applied to the liquid crystal element to be
Liquid crystal element selected at the
Crystal element, the polarity of the applied erase pulse and select pulse
The selection period is reduced by half
Can be. Also, lower the voltage applied to the scanning electrodes.
It is a driving method that can be used. In this comparative example, immediately before selecting a liquid crystal element.
The erase pulse is applied to the
There is no need to put out immediately before the selection period, some time after the selection period
An erase pulse may be applied before. Comparative Example23 FIG. 72 shows a specific example of realizing the drive waveform in this comparative example.
FIG. 2 is a block diagram showing a logical circuit. 721 is a frame signal
722 is a clock signal. These 721 and 722
The transmission gate 111 is switched by the signal of
Touch, V₁, V_Two, -V_Three, -V_FourTurn off the voltage
Instead, a scan electrode selection waveform 725 is generated. Also,
V_Five, -V_FiveOf the signal electrode ON waveform 72
6 and the signal electrode off waveform 727. These waves
A timing chart of the shape is shown in FIG. 73. FIG. 73
25, 726, and 727 are input to the drive circuit shown in FIG.
725 is 8101, 8102 and 726 is 81
05, 727 is 8104, 8103 is 0 volt,
Connect each. FIG. 66 shows scanning electrode data.
By the shift clock 120.
To the star 115, and sequentially select signals one scanning line at a time.
put out. The transmission gate is selected by this selection signal.
Switch 111 to create 8107 scan electrode waveforms
ing. FIG. 117 shows signal electrode data.
The shift clock 118 controls the signal electrode side shift register.
Transferred to the star 114 and transferred data for one scanning line
Sometimes the latch signal of 119 causes the latch circuit of 116
Latch. With this latch output, 111
Switching the transmission gate, 8104, 8
105 signals are switched to create 8106 signal electrode waveforms.
ing. 8107 and 8106, and the composite wave
Figure 74 shows the timing charts of 741, 742 and 743.
Shown in the chart. The driving conditions of this driving waveform are as follows.
Swell. [0233] V₁> Vsat₁                    (V_Two+ V_Five)> Vsat₁ (V_Two-V_Five) <Vth₁            (-V_Three-V_Five)> | Vsat_Two| | -V_Three+ V_Five| <| Vth_Two| | -V_Four|> | Vsat_Two| ｜ V₁| = | −V_Four｜ ｜ V_Two| = | −V_Three| V_Five<Vth₁                      | -V_Five| <| Vth_Two| t₁₄= T_Fifteen= T₁₆ Description of the operation of the liquid crystal element for the pixel in FIG.
Then, FIG. 74 t₁₁Is an odd frame selection period
Yes, t₁₄Is the erase pulse, which is more than the negative saturation voltage.
A voltage pulse with a large value is applied, and the liquid crystal element
The memory state is erased and the memory cell is turned off. And t_Fifteenof
Between the write pulse and the signal electrode waveform is the ON waveform
For example, the voltage applied to the liquid crystal element is higher than the positive saturation voltage.
The liquid crystal element is turned on, and the signal electrode waveform is turned off.
Voltage, the voltage applied to the liquid crystal element is a positive threshold voltage.
And the liquid crystal element remains off. Soshi
And t₁₆The voltage applied to the scan electrode during
I do. In addition, the non-selection period t₁₂Is an absolute value from the threshold voltage
Small V_Five, -V_FiveVoltage is applied to the liquid crystal element.
So t_FifteenThe state written during is maintained. Next, the selection period of the even-numbered frame will be described.
Then t_{twenty one}Is the selection period, t_{twenty four}Is the erase pulse
The positive saturation voltage of a voltage of the opposite polarity to that of the odd frame
The liquid crystal element is turned on by applying a voltage pulse
Become. And t_{twenty five}Is the write pulse and the signal electrode
If the waveform is an ON waveform, the voltage applied to the liquid crystal element
Means that the absolute value is smaller than the negative threshold voltage,
Remains in the erased ON state, and the signal electrode waveform is turned off.
Voltage, the voltage applied to the liquid crystal element is negatively saturated.
A voltage pulse whose absolute value is larger than the sum voltage is applied and the liquid crystal
The element is turned off. And t₂₆Between the scanning electrodes
The applied voltage is zero volt. The non-selection period t_{twenty two}In between, odd frames
T_{twenty five}Keep state written during
I do. With such a drive, during the non-selection period
The pulse width of the applied voltage pulse is always t₁₄Constant in width
Therefore, the uneven contrast is eliminated. Comparative Example24 FIG. 75 shows a specific example of realizing the driving waveform in this comparative example.
FIG. 2 is a block diagram showing a logical circuit. 751 is a frame signal
And 752 is a clock signal. These 751, 752
The transmission gate 111 is switched by the signal of
Touch, V₁, -V_Two, -V_Three, -V₆, −
V₇, -V₈Of the scan electrode selection waveform 75
Make 5 and -V_Three, -V₆Switch the scanning voltage
An unselected waveform 756 is created. Also, -V_Two, −
V_Three, -V_Four, -V_Five, -V₆, -V₇Switch the voltage of
The signal electrode ON waveform 757 and the signal electrode OFF waveform 75
I'm making 8. The timing chart of these waveforms
As shown in FIG. Fig. 76 755, 756, 757, 7
The signal 58 is input to the drive circuit shown in FIG.
101, 8102, 756 is 8103, and 757 is 8.
105 and 758 are connected to 8104, respectively. So
66, 117, 118, 119, 120 and 12
Comparative example by each signal of 123The same operation as
7 The scan electrode waveform of FIG. 771 and the signal electrode waveform of 772 are
And apply it to the liquid crystal element.
You. The driving conditions of this driving waveform are as follows.
You. [0237] V₁= 0 | -V₈+ V_Three|> | Vsat_Two| (-V_Two+ V_Five) <Vth₁        (-V_Two+ V₇)> Vsat₁ (V₁+ V₆)> Vsat₁        | -V₇Ten volts_Two|> | Vsat_Two| | -V₇+ V_Three| <| Vth_Two| (−V_Two+ V_Three) <Vth₁ | -V_Four+ V_Three| <| Vth_Two| (−V_Two+ V_Three) = (− V_Five+ V₆) (-V_Four+ V_Three) = (− V₇+ V₆) (-V_Two+ Vm) = (− Vm + V₇) t₁₄= T_Fifteen= T₁₆ (V₈-V_Three) = (V₆-V₁) (V₆-V_Two) = (V₇-V_Three) Description of the operation of the liquid crystal element for the pixel in FIG.
Then, FIG. 77 t₁₁Is an odd frame selection period
Yes, t₁₄Is the erase pulse, which is more than the negative saturation voltage.
A voltage pulse with a large value is applied, and the liquid crystal element
The memory state is erased and the memory cell is turned off. And t_Fifteenof
Between the write pulse and the signal electrode waveform is the ON waveform
For example, the voltage applied to the liquid crystal element is higher than the positive saturation voltage.
The liquid crystal element is turned on, and the signal electrode waveform is turned off.
Voltage, the voltage applied to the liquid crystal element is a positive threshold voltage.
And the liquid crystal element remains off. Soshi
And t₁₆The voltage applied to the scanning electrode during_ThreeToss
You. In addition, the non-selection period t₁₂Is the scan electrode waveform 771
-V_Three, -V₆Are applied alternately, and the
In the composite waveform, as shown by 773, it is always higher than the threshold voltage.
Since only a voltage having a small absolute value is applied to the liquid crystal element, t
_FifteenHold the state between. Next, for even frames
Looking at, t_{twenty one}Is the selection period, t_{twenty four}The erase pulse is between
And the positive saturation voltage of the opposite polarity to that of the odd-numbered frame
When the above voltage pulse is applied, the liquid crystal element is turned on.
You. And t_{twenty five}Is the write pulse and the signal electrode wave
If the shape is an ON waveform, the voltage applied to the liquid crystal element is
The absolute value is smaller than the negative threshold voltage, and the liquid crystal element is turned off.
And the signal electrode waveform is turned off.
Voltage, the voltage applied to the liquid crystal element is
A voltage pulse whose absolute value is larger than the
The child is turned off. And t₂₆Mark on the scanning electrode during
The applied voltage is -V₆And The non-selection period t_{twenty two}In between, odd frames
T as well as_{twenty five}Hold the state between. Such a drive
In the case of, the composite waveform applied to the liquid crystal element
An example23Same as above, but lower the voltage applied to the scan electrodes.
It is a driving method that can be performed. Comparative Example25 Figure 68 shows the effect of memory state retention by AC bias
The figure is shown. V is the voltage applied to the liquid crystal element, and I is the liquid
3 shows a transmission state of the crystal element. V for liquid crystal element₁Voltage
And I₁And then apply 0
And the liquid crystal element is I₁Memory gradually from the state
Becomes worse, and as shown by the dotted line, I_FiveUntil the memory drops
Go on. However, by applying an AC bias,
Improve the badness of memory_ThreeTo keep in the state of
Can be. Fig. 78 utilizes the effect of this AC bias.
Block diagram showing a specific circuit for realizing the drive waveform of this comparative example.
FIG. 781 is a frame signal, 782 is polarity
This is a switching signal. These 781 and 782 signals cause
To switch the transmission gate 111
And V_Two, V_Three, -V_Four, -V_FiveRun by switching the voltage of
A test electrode selection waveform 784 is created, and the signal
V₁, -V₆, The scan electrode non-selection waveform 7
I'm making 85. In addition, V₇, -V₈Switch the voltage of
Signal electrode on waveform 786 and signal electrode off waveform 787
ing. The timing chart of these waveforms is shown in FIG.
Shown in the figure. 79 of FIG. 784, 785, 786, 787
The signal is input to the drive circuit of FIG.
1, 8102 and 785 are 81103 and 786 are 81
05 and 787 are connected to 8104, respectively. Sixth
6 FIG. 121 shows scan electrode data, which is a shift clock.
120 to the scan electrode side shift register 115
And sends out a selection signal one scanning line at a time.
To switch transmission gate 111
8107 to form a scan electrode waveform. FIG. 66 117 shows signal electrode data.
Is shifted by the shift clock 118 to the signal electrode side shift register.
Transferred to the star 114 and transferred data for one scanning line
Sometimes, the latch signal 119 causes the latch circuit 116 to
The transmission of this latch
Switching gate 111 to 8104 and 8105
8106 signal electrode waveforms
You. The waveforms of 8107 and 8106 and the sum of the waveforms
The timing chart of the formed waveform is shown in FIGS.
2, 803. The following shows the driving conditions of this waveform.
Become like [0242] ｜ V₁| = | −V₆｜ ｜ V₇| = | −V₈| | -V_Five+ V₇|> | Vsat_Two| (V_Three+ V₈)> Vsat₁ (V_Three-V₇) <Vth₁            (V_Two-V₇)> Vsat₁ | -V_FourTen volts₈| <| Vth_Two| (−V_Four-V₇)> | Vsat_Two| V₇<Vth₁                      | -V₈  | <| Vth_Two| ｜ V_Two| = | −V_Five｜ ｜ V_Three| = | −V_Four| t₁₄= T_Fifteen Description of the operation of the liquid crystal element for the pixel in FIG.
Then, FIG. 80 t₁₁Is the odd frame selection period
And t during this period₁₄Between the erase pulse and the negative saturation voltage.
Voltage pulse whose absolute value is larger than the
The molly state is erased and turned off. And t_Fifteen
Is a write pulse and the signal electrode waveform is an ON waveform.
If applied, a voltage pulse higher than the positive saturation voltage is applied to the liquid crystal element.
The liquid crystal element is turned on and the signal electrode waveform is turned off.
If it has a waveform, the liquid crystal element will have a voltage pattern below the positive threshold voltage.
A liquid is applied and the liquid crystal element remains off. So
Then t₁₂Is the non-selection period and high frequency AC bias is applied
Add. The frequency and voltage of this high frequency AC bias
Frequency and voltage that the crystal molecules can respond to.
The frequency is several KHz to several hundred KHz, and the voltage is several tens
It is a bolt. The AC bias during this non-selection period
Improves the memory characteristics of the liquid crystal element to retain data
You. Next, regarding the even frame, t_{twenty one}Between
Selection period, t during this period_{twenty four}Between the erase pulses, odd number
A voltage higher than the positive saturation voltage of the opposite polarity to that of the frame
A liquid is applied to the liquid crystal element, and the liquid crystal element is turned on. And
t_{twenty five}Is the write pulse and the signal electrode waveform is the ON waveform
, The absolute value of the liquid crystal element is smaller than the negative threshold voltage.
The liquid crystal element remains in the ON state
If the signal electrode waveform is an off waveform, the liquid crystal element is negative.
Voltage pulse whose absolute value is larger than the saturation voltage of
The liquid crystal element is turned off. And the non-selection period is odd
As in the case of the frame,
Hold the Molly state. In each of the above embodiments, the binary
The drive method in display was explained.
Can be driven in the same way,
The waveform to be added may be the same as in the above-described embodiment, and the signal
By changing the voltage applied to the electrodes according to the gradation data,
Threshold voltage applied to the liquid crystal element during the write pulse
What is necessary is just to change between a voltage and a saturation voltage. Also, gradation
The pulse width of the signal electrode waveform is changed according to the data
By doing so, a gradation display can be performed. [0243] As described above, according to the present invention, the erasure is performed.
Pulse of voltage pulse applied to scan electrode when voltage is applied
Wide width is ensured. Therefore, the height of the voltage pulse
Even if the value is not so large, the effective value of the erase voltage can be increased.
Liquid crystal alignment maintained in the previous frame
Can be surely erased. Therefore, after this the liquid crystal
Depending on the selection voltage applied to the liquid crystal in the previous frame
Without depending on the state of the
It is possible to set the liquid crystal molecules in the column direction. [0244]

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) and 1 (b) are views showing an arrangement state of molecules of a ferroelectric liquid crystal. FIG. 2 (a) is a sectional view showing an example of a liquid crystal element used in each embodiment of the present invention, and FIG. 2 (b) is a liquid crystal element shown in FIG. 2 (a). The figure which shows the electrode structure of FIG. FIG. 3 is a diagram showing a relationship between a drive waveform and light transmission characteristics according to the first embodiment of the present invention. FIG. 4 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in FIG. FIG. 5 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 4; FIG. 6 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 1. 7 is a diagram showing an example of a specific circuit for realizing the driving waveform shown in FIG. 6; FIG. 8 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 7; FIG. 9 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 2. FIG. 10 is a diagram showing an example of a specific circuit for realizing the driving waveforms shown in FIG. 9; FIG. 11 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 10; FIG. 12 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 3. FIG. 13 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in FIG. FIG. 14 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 13; FIG. 15 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 4 of the present invention. 16 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in FIG. 17 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 16; FIG. 18 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 5 . FIG. 19 is a diagram showing an example of a specific circuit for realizing the driving waveform shown in FIG. 18; FIG. 20 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 19; FIG. 21 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 6 . FIG. 22 is a diagram showing an example of a specific circuit for realizing the driving waveform shown in FIG. 21; FIG. 23 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 22; FIG. 24 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 7 . FIG. 25 is a diagram showing an example of a specific circuit for realizing the driving waveform shown in FIG. 24; FIG. 26 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 25; FIG. 27 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 8 of the present invention. FIG. 28 is a diagram showing an example of a specific circuit for realizing the driving waveform shown in FIG. 27; FIG. 29 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 28; FIG. 30 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 9 . FIG. 31 is a diagram showing an example of a specific circuit for realizing the driving waveform shown in FIG. 30; FIG. 32 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 31; FIG. 33 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 10 . FIG. 34 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in FIG. 33; FIG. 35 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 34; FIG. 36 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 11 . FIG. 37 is a diagram showing an example of a specific circuit for realizing the driving waveform shown in FIG. 36; FIG. 38 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 37; FIG. 39 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 12 . FIG. 40 is a diagram showing an example of a specific circuit for realizing the driving waveforms shown in FIG. 39; FIG. 41 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 40; FIG. 42 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 13 . FIG. 43 is a diagram showing an example of a specific circuit for realizing the driving waveform shown in FIG. 42; FIG. 44 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 43; FIG. 45 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 14 of the present invention. 46 is a timing chart of signal waveforms at respective points of the circuit shown in FIG. 45 and a diagram showing a relationship between driving waveforms and light transmission characteristics. FIG. 47 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 15 . FIG. 48 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 47; FIG. 49 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 15 . FIG. 50 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 16 ; FIG. 51 is a timing chart of signal waveforms at each point of the circuit shown in FIG. 50 and a diagram showing a relationship between drive waveforms and light transmission characteristics. FIG. 52 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 17 ; FIG. 53 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 52; FIG. 54 is a view showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 17 . FIG. 55 is a view showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 18 . FIG. 56 is a timing chart of signal waveforms at each point of the circuit shown in FIG. 55 and a diagram showing a relationship between drive waveforms and light transmission characteristics. FIG. 57 is a view showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 19 ; FIG. 58 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 57; FIG. 59 is a view showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 19 . FIG. 60 is a view showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 20 ; FIG. 61 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 60; FIG. 62 is a view showing a relationship between a driving waveform and a light transmission characteristic shown in Comparative Example 20 ; FIG. 63 is a view showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 21 ; FIG. 64 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 63; FIG. 65 is a diagram showing a relationship between a driving waveform and a light transmission characteristic shown in Comparative Example 21 . FIG. 66 is a diagram showing an example of a drive circuit used in each embodiment of the present invention. 67 (a) and 67 (b) are diagrams showing a change in light transmission characteristics depending on a waveform of an applied voltage. FIG. 68 is a diagram showing a relationship between a driving waveform when an AC bias voltage is applied and a light transmission characteristic. FIG. 69 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 22 . FIG. 70 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 69; FIG. 71 is a view showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 22 . FIG. 72 is a diagram showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 23 . FIG. 73 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 72; FIG. 74 is a diagram showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 23 . FIG. 75 is a view showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 24 ; FIG. 76 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 75; FIG. 77 is a view showing a relationship between a driving waveform and light transmission characteristics shown in Comparative Example 24 . FIG. 78 is a view showing an example of a specific circuit for realizing the drive waveform shown in Comparative Example 25 ; FIG. 79 is a timing chart showing signal waveforms at respective points of the circuit shown in FIG. 78; FIG. 80 is a view showing a relationship between a drive waveform and light transmission characteristics shown in Comparative Example 25 ; [Description of Signs] 11 ・ 12 Substrate 13 Scanning electrode 14 Signal electrode 15 Alignment film 16 Ferroelectric liquid crystal 17 18 Polarizing plate 19 Sealant 111 Transmission gate 112 Flip-flop 113 Liquid crystal element 114 ... Signal electrode side soft register 115 ... Scan electrode side soft register 116 ... Latch circuit 117 ... Signal electrode data 118 ... Signal electrode soft clock 119 ... Latch signal 120 ... Scan electrode shift clock 121 ... Scan electrode data

──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 60-258181 (32) Priority date November 18, 1985 (33) Priority claim country Japan (JP) (31) Priority Claim No. Japanese Patent Application No. 61-45868 (32) Priority date March 3, 1986 (33) Priority claiming country Japan (JP) Preliminary examination (58) Fields investigated (Int. Cl. ⁶ , DB Name) G02F 1/133 G09G 3/36

Claims (1)

(57) [Claims] In a method for driving a liquid crystal element in which a liquid crystal having a memory property is sandwiched between a substrate having a scanning electrode group and a substrate having a signal electrode group, a scanning signal is applied to the scanning electrode group, A data signal is applied to the signal electrode group, and the scanning signal and the data signal are used to set an erasing voltage for aligning the liquid crystal molecules in a predetermined alignment direction and to set the liquid crystal molecules in an alignment direction corresponding to a display state. A first voltage pulse applied to the scan electrode when the erase voltage is applied, and a second voltage pulse applied to the scan electrode when the select voltage is applied. Wherein the pulse width of the first voltage pulse is set wider than the pulse width of the second voltage pulse. When an intermediate potential of the data signal is set as a reference potential, the data signal is And applying the data signal, which has a negative binary voltage level and whose voltage level is inverted with respect to the reference potential, to the signal electrode during a period in which the first voltage pulse is applied to the scan electrode. A method for driving a liquid crystal element. 2. 2. The method according to claim 1, wherein a peak value of the first voltage pulse applied to the scan electrode when the erase voltage is applied is constant. 3. 3. The device according to claim 1, wherein an integral value of the first voltage pulse applied to the scan electrode when the erase voltage is applied is greater than an integral value of the second voltage pulse applied to the scan electrode when the select voltage is applied. A method for driving a liquid crystal element.