CN102622972A - Unidirectional pulse driving method of smectic state liquid crystal display - Google Patents
Unidirectional pulse driving method of smectic state liquid crystal display Download PDFInfo
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- CN102622972A CN102622972A CN2011100330493A CN201110033049A CN102622972A CN 102622972 A CN102622972 A CN 102622972A CN 2011100330493 A CN2011100330493 A CN 2011100330493A CN 201110033049 A CN201110033049 A CN 201110033049A CN 102622972 A CN102622972 A CN 102622972A
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Abstract
The invention discloses a unidirectional pulse driving method of a smectic state liquid crystal display. The method comprises the following step: carrying out line-by-line scanning driving on a display screen, wherein scanning and driving one line comprises: applying corresponding voltage waveforms to each row and each column in a scanning phase; applying 0v voltage to all the rows and the columns in a group phase; applying the corresponding voltage waveforms to the each row and the each column in a DC equilibrium phase, wherein the voltage waveforms applied to the each row and the each column in the scanning phase has a certain of corresponding relationship with the voltage waveforms applied to the each row and the each column in the DC equilibrium phase. Therefore, by using the method of the invention, under the condition that DC equilibrium can be guaranteed during a whole period, scanning and driving can be realized only with the unidirectional voltage waveform. It is simple to drive the voltage waveform. Driving difficulty is low and hardware circuit cost is low.
Description
Technical field
The present invention relates to a kind of scanning drive method of smectic liquid crystal display screen, refer to a kind of smectic liquid crystal display screen unidirectional pulse driving method especially.
Background technology
At present, smectic liquid crystal display screen uses the high-frequency and high-voltage positive negative pulse stuffing to be used as driving the voltage waveform of row, row electrode.For example, this high-frequency and high-voltage positive negative pulse stuffing can be the wave form of positive negative pulse stuffing to realizing that is made up of positive pulse shown in Fig. 1 and negative pulse, and this waveform is by positive-negative power supply; Voltage magnitude is Um, needs 2 groups of high-voltage isolator spares to realize, waveform is realized complicated; The driving difficulty is big, and it is many to expend cost.If apply the high-frequency and high-voltage positive negative pulse stuffing of different voltage magnitudes on row, the row electrode, then need 4 groups of high-voltage isolator spares to realize, like this, just increased the complexity that waveform is realized more, increased the driving difficulty, promoted cost.Therefore, designing that a kind of driving voltage waveform is simple, energy consumption is little, driving the little driving method of difficulty is the present technical issues that need to address.
Summary of the invention
The object of the present invention is to provide a kind of smectic liquid crystal display screen unidirectional pulse driving method, this method realizes simple, and is low in energy consumption, can greatly reduce the cost of the hardware driving circuit of row-column electrode voltage waveform (as provide).
To achieve these goals, the present invention has adopted following technical scheme:
A kind of smectic liquid crystal display screen unidirectional pulse driving method, it comprises: all the capable drivings of lining by line scan to this smectic liquid crystal display screen is characterized in that: each row of turntable driving comprises the steps:
Step 1: sweep time: this row to turntable driving applies the pulse of line scanning phase, and this line scanning phase pulse is that frequency is that fscan, dutycycle are that Dscan, amplitude are the high frequency unidirectional pulse of Um; Other row to turntable driving not apply zero volt voltages; The corresponding row of pixel that on this row of turntable driving, need be driven to the bright state of full impregnated apply full clear state column scan phase pulse, and only phase place is opposite for this full clear state column scan phase pulse and the pulse of line scanning phase; The corresponding row of pixel of vaporific shading state apply vaporific lucifuge attitude column scan phase pulse when on this row of turntable driving, needing to keep initial, and this vaporific lucifuge attitude column scan phase pulse and line scanning phase pulsion phase are together;
Step 2: return the ground phase: apply zero volt voltage to all row and all row, the duration is tgnd;
Step 3: DC balance period: this row to turntable driving applies capable balance period pulse, and this row balance period pulse is that frequency is that fdc, dutycycle are that Ddc, amplitude are the high frequency unidirectional pulse of Um; Other row to turntable driving not apply the voltage that amplitude is Um; The corresponding row of pixel that on this row of turntable driving, need be driven to the bright state of full impregnated apply full clear state column balancing phase pulse, and only phase place is opposite with the pulse of row balance period in this full clear state column balancing phase pulse; The corresponding row of pixel of vaporific shading state apply vaporific shading attitude column balancing phase pulse in the time of on this row of turntable driving, need keeping initial, and this vaporific shading attitude column balancing phase pulse and row balance period pulsion phase are together;
Wherein: frequency f scan equals frequency f dc, and dutycycle Dscan equals dutycycle Ddc, and the pulse number Qscan of the line scanning phase pulse that applies sweep time equals the pulse number Qdc of the capable balance period pulse that the DC balance period applies.
Advantage of the present invention is:
Unidirectional pulse driving method of the present invention only needs the unidirectional voltage waveform to realize, the unidirectional voltage waveform is realized simple, has reduced the driving difficulty of row, row pulse voltage driving circuit, has reduced the cost of hardware circuit.
Through adopting the method for returning ground phase and DC balance period that is provided with, the present invention has guaranteed that in the whole cycle voltage integrating meter on all pixels is 0 on the basis of realizing the unidirectional voltage drive waveform, realized the DC balance, has guaranteed the normal demonstration of display screen to image.
Description of drawings
Fig. 1 is a smectic liquid crystal display screen instance graph of the high-frequency and high-voltage positive negative pulse stuffing of use at present;
Fig. 2 is the composition synoptic diagram of smectic liquid crystal display screen;
Fig. 3 is arranged in the first and second conductive electrode layer synoptic diagram of lattice array shape anyhow;
Fig. 4 is the realization flow figure of turntable driving delegation among the present invention;
Fig. 5 is to the voltage waveform that delegation applied of turntable driving in the first embodiment of the invention;
Fig. 6 is the voltage waveforms that applied to other row of turntable driving not in the first embodiment of the invention;
Fig. 7 is the corresponding voltage waveform that row applied of pixel that in the delegation of turntable driving, need be driven to the bright state of full impregnated in the first embodiment of the invention;
Fig. 8 is the corresponding voltage waveform that row applied of pixel of vaporific shading state when in the delegation of turntable driving, needing maintenance initial in the first embodiment of the invention;
Fig. 9 is the voltage waveform that voltage waveform shown in Figure 5 and voltage waveform shown in Figure 7 stack back form;
Figure 10 is the voltage waveform that voltage waveform shown in Figure 5 and voltage waveform shown in Figure 8 stack back form;
Figure 11 is the voltage waveform that voltage waveform shown in Figure 6 and voltage waveform shown in Figure 7 stack back form;
Figure 12 is the voltage waveform that voltage waveform shown in Figure 6 and voltage waveform shown in Figure 8 stack back form;
Figure 13 is the Action Specification figure that returns the ground phase;
Figure 14 is the defined declaration figure of a pulse.
Embodiment
Smectic liquid crystal display screen unidirectional pulse driving method of the present invention is a kind of method that is used on the smectic liquid crystal display screen.As shown in Figures 2 and 3, this smectic liquid crystal display screen 10 comprises that the material of first base layer 11 and second base layer, 12, the first base layers 11 and second base layer 12 is chosen as transparent glass or plastics.Between first base layer 11 and second base layer 12, be provided with the mixolimnion 13 that forms by smectic phase liquid crystal and additives mixed.This smectic phase liquid crystal (show as the smectic phase liquid crystal molecule on the microcosmic, state as follows) in compound, four cyano four octyl group biphenyl or tetraacethyl ester in the last of the ten Heavenly stems four cyano biphenyl of band siloxy any or appoint several kinds potpourri.Additive is the compound of band conductive characteristic, contains the compound of conductive ion like cetyltriethylammonium bromide etc.Be coated with first conductive electrode layer 14 at first base layer 11 towards a side of mixolimnion 13; Be coated with second conductive electrode layer 15 at second base layer 12 towards a side of mixolimnion 13; As shown in Figure 3, first conductive electrode layer 14 is made up of M strip line electrode 141 that is arranged in parallel, and this M column electrode 141 is drawn from the column electrode exit on these smectic liquid crystal display screen 10 left sides and is connected to horizontal pulse Voltag driving circuit (not shown); In this application; A column electrode is regarded as delegation, and second conductive electrode layer 15 is made up of N strip row electrode 151 that is arranged in parallel, and this N row electrode drawn from the row electrode leads to client of these smectic liquid crystal display screen 10 tops and be connected to row pulse voltage driving circuit (not shown); In this application; A row electrode is regarded as row, and N row electrode 151 of the M of first conductive electrode layer 14 column electrode 141 and second conductive electrode layer 15 be quadrature mutually, and this first conductive electrode layer 14 and second conductive electrode layer 15 form the pixel-matrix array structure (M, N are positive integer) of a M * N; A column electrode and a row electrode form a pixel, pixel 20 for example shown in Figure 3.That is to say, display screen be M capable * N row standard, have that M is capable, N row, delegation is to there being N pixel.In the present invention, applying voltage waveform to row is to realize through applying voltage waveform to the corresponding column electrode of this row, and in like manner, applying voltage waveform to row is through realizing to the corresponding row electrode application voltage waveform of these row.These two conductive electrode layers 14 and 15 and middle mixolimnion 13 formed a capacitance structure that area is very big.First conductive electrode layer 14 and second conductive electrode layer 15 are transparent, and it can be ITO (tin indium oxide) etc., and can use auxiliary metal electrode as required, like aluminium, copper, silver etc.This display screen can be provided with the black backboard or backboard is not set.
The present invention includes following steps:
To all capable drivings of lining by line scan of this smectic liquid crystal display screen 10, wherein: each row of turntable driving comprises the steps, and is as shown in Figure 4:
Step 1: sweep time Pscan: apply the pulse of line scanning phase to this row of turntable driving and (understand for ease; Below the pulse of line scanning phase is called the A pulse), this A pulse is that frequency is that fscan (cycle T scan=1/fscan), dutycycle are that Dscan, amplitude are the high frequency unidirectional pulse of Um; Other row to turntable driving not apply zero volt voltages; The corresponding row of pixel that on this row of turntable driving, need be driven to the bright state of full impregnated apply full clear state column scan phase pulse and (understand for ease; Below full clear state column scan phase pulse is called the B pulse); This B pulse and A pulse be phase place opposite (voltage direction, frequency, dutycycle, amplitude, the pulse number of voltage direction, frequency, dutycycle, amplitude, pulse number and A pulse that refers to the B pulse is all identical, but phase place is opposite) only; The corresponding row of pixel of vaporific shading state apply vaporific lucifuge attitude column scan phase pulse (understanding for ease when on this row of turntable driving, needing to keep initial; Below vaporific lucifuge attitude column scan phase pulse is called the C pulse), this C pulse and A pulsion phase are with (voltage direction, phase place, frequency, dutycycle, amplitude, the pulse number of voltage direction, phase place, frequency, dutycycle, amplitude, pulse number and A pulse that refers to the C pulse is all identical);
Step 2: return ground phase Pgnd: apply zero volt voltage to all row and all row, the duration is tgnd;
Step 3: DC balance period Pdc: this row to turntable driving applies capable balance period pulse (understanding for ease; The balance period pulse of below will going is called the D pulse), this D pulse is that frequency is that fdc (cycle T dc=1/fdc), dutycycle are that Ddc, amplitude are the high frequency unidirectional pulse of Um; Other row to turntable driving not apply the voltage that amplitude is Um; The corresponding row of pixel that on this row of turntable driving, need be driven to the bright state of full impregnated apply full clear state column balancing phase pulse and (understand for ease; Below full clear state column balancing phase pulse is called the E pulse); This E pulse and D pulse be phase place opposite (voltage direction, frequency, dutycycle, amplitude, the pulse number of voltage direction, frequency, dutycycle, amplitude, pulse number and D pulse that refers to the E pulse is identical, but phase place is opposite) only; The corresponding row of pixel of vaporific shading state apply vaporific shading attitude column balancing phase pulse (understanding for ease when on this row of turntable driving, needing to keep initial; Below vaporific shading attitude column balancing phase pulse is called the F pulse), this F pulse and D pulsion phase are with (voltage direction, phase place, frequency, dutycycle, amplitude, the pulse number of voltage direction, phase place, frequency, dutycycle, amplitude, pulse number and D pulse that refers to the F pulse is all identical);
Wherein: frequency f scan equals frequency f dc; Dutycycle Dscan equals dutycycle Ddc; The pulse number Qscan of the A pulse that sweep time, Pscan applied equals the pulse number Qdc of the D pulse that DC balance period Pdc applies, and that is to say that the duration of sweep time equals the duration of DC balance period.The initial phase that it should be noted that the D pulse that applies in initial phase and the DC balance period of the A pulse that applies in sweep time can be identical or different.
In sum, delegation successively continuously through sweep time, return ground phase, DC balance period after, just accomplished the turntable driving operation of this row.After delegation finished turntable driving, just next line is carried out turntable driving, intact until all row of display screen by turntable driving.After all line scannings drove completion, image refreshing was accomplished, and image just shows.
Can set by actual demand all of display screen orders that line scannings drive of advancing, for example, can be in sequential scanning drivings line by line, backward turntable driving, fractional scanning driving, two fens algorithm turntable driving or the out of order at random turntable driving any.
This high frequency unidirectional pulse can be direct impulse or negative-going pulse (being that voltage direction is forward or negative sense).When this high frequency unidirectional pulse was direct impulse, the amplitudes that apply to other row of turntable driving not in the DC balance period were that the voltage of Um should be positive voltage.When this high frequency unidirectional pulse was negative-going pulse, the amplitudes that apply to other row of turntable driving not in the DC balance period were that the voltage of Um should be negative voltage.
In the present invention, be to realize to the judgement of the pixel of the pixel of the bright state of full impregnated and vaporific shading state through the record in the reading images storer, each pixel state to be shown with the behavior unit record in this video memory.
In the present invention, the frequency f scan of this high frequency unidirectional pulse is 1kHz≤fscan≤25kHz, and amplitude Um is 10V≤Um≤250V; Amplitude Um is greater than threshold voltage magnitude Uth; In sweep time, the pulse number Qscan that applies the high frequency unidirectional pulse is 1≤Qscan≤2000; Dutycycle Dscan can set arbitrarily.It should be noted that; Limit by row, the used chip internal resource of row pulse voltage driving circuit; The frequency of this high frequency unidirectional pulse should be 1kHz～25kHz, and pulse number can not surpass 2000, and; Limit by row, row pulse voltage drive circuit works characteristic, the scope of amplitude Um should be 10V～250V.For example, the frequency of this high frequency unidirectional pulse can be 1kHz, 4kHz, 10kHz, 15kHz, 20kHz, 25kHz, and pulse number can be 1,500,1000,1500,2000, and amplitude Um can be 10V, 50V, 100V, 150V, 250V.
In reality is implemented, the Pwait waiting period of also can comprising before the step 1; The waiting period in, apply zero volt voltage to all row and all row.
In addition; Before the driving of lining by line scan, also comprise the initialization step of removing images displayed on the smectic liquid crystal display screen 10; This initialization step is: in the initialization phase; Apply capable initialization pulse to all row, this row initialization pulse is the low frequency unidirectional pulse, applies the row initialization pulse to all row; This row initialization pulse and this row initialization pulse be phase place opposite (voltage direction, frequency, dutycycle, amplitude, the pulse number that refer to the row initialization pulse are all identical with voltage direction, frequency, dutycycle, amplitude, the pulse number of capable initialization pulse, but phase place is opposite) only.
The purpose of initialization smectic liquid crystal display screen is that the smectic liquid crystal display screen images displayed is removed, and to the full frame initialization operation that carries out unanimity, can be in full frame vaporific lucifuge (frosted) state through the display screen after the initialization.
In initialization step, this low frequency unidirectional pulse can be direct impulse or negative-going pulse; The frequency f init of this low frequency unidirectional pulse is 1Hz≤finit＜1000Hz, and amplitude Un is 10V≤Un≤250V; Amplitude Un is greater than threshold voltage magnitude Uth; In the initialization phase, the pulse number Qinit that applies the low frequency unidirectional pulse is 1≤Qinit≤500; The dutycycle Dinit of this low frequency unidirectional pulse can set arbitrarily.The pulse number that it should be noted that this low frequency unidirectional pulse is controlled at 500 (comprising 500) and just can realizes the cls effect with interior, limit by row, row pulse voltage drive circuit works characteristic, and the scope of amplitude Un should be 10V～250V.For example, the frequency of this low frequency unidirectional pulse can be 1Hz, 50Hz, 500Hz, 800Hz, 990Hz, and pulse number can be 1,50,100,500, and amplitude Un can be 10V, 50V, 100V, 150V, 250V.
To shown in Figure 12, principle of work of the present invention and process are like Fig. 5:
At first, display screen is carried out initialization.In the initialization phase, applying frequency f init to all row and all row is that 100Hz, dutycycle Dinit are 50%, amplitude Un is the low frequency direct impulse of 80V, and applying pulse number Qinit is 400, and only phase place is opposite in the pulse that applies on row and the row.Because row, list the voltage waveform that applies be low frequency bidirectional pulse and row, row between the two the amplitude of the voltage waveform that forms in each moment of stack back be 80V; Greater than threshold voltage magnitude (selected threshold voltage magnitude is 50V); Therefore; When voltage action time less than 1 second the time, the smectic phase liquid crystal molecule in the mixolimnion 13 just twists, and forms out of order arrangement form.Because each of smectic phase liquid crystal molecule (promptly passed through the long optical axis difference of each liquid crystal to diversity owing to incident ray; The anaclasis angle of each liquid crystal is different, thereby the refractive index of each liquid crystal is different), make the ray refraction of each smectic phase liquid crystal molecule of incident exist very big difference; Promptly in the mixolimnion 13 of this meagre thickness; Optical index is producing violent variation, thereby strong scattering has taken place light, shows as a kind of astigmatic effect on the macroscopic view; Display screen is full frame to present vaporific shading state, as acute-matte.
Then, display screen is carried out line by line sequential scanning driving (promptly scanning by walking to the capable order of M from the 1st) line by line,, at this moment, need images displayed just to show until all line scannings have been driven.
Describe with turntable driving one behavior example below.
The waiting period of before formal turntable driving be, the waiting period in, all row and all list and all are applied in 0 volt voltage, the turntable driving step that wait is following.
Then; Get into Pscan sweep time; In sweep time: apply the A pulse on this row of turntable driving; This A pulse is that frequency f scan is that 5kHz, dutycycle Dscan are 50%, amplitude Um is the high frequency direct impulse of 80V, and as shown in Figure 5, the pulse number Qscan of the A pulse that applies in sweep time is 200; Do not apply 0 volt of voltage on other row of turntable driving, as shown in Figure 6; Corresponding the listing of pixel that need be driven to the bright state of full impregnated on this row of turntable driving applies the B pulse, and this B pulse is identical with voltage direction, frequency, dutycycle, the pulse number of A pulse, and phase place is opposite, and is as shown in Figure 7; Corresponding the listing of pixel of vaporific shading state applies the C pulse when needing on this row of turntable driving to keep initial, and this C pulse is all identical, as shown in Figure 8 with voltage direction, phase place, frequency, dutycycle, the pulse number of A pulse;
Then, get into and return ground phase Pgnd, returning in the ground phase: all row and all list and all apply 0 volt of voltage, and the duration is tgnd, and are extremely shown in Figure 8 like Fig. 5;
At last; Get into DC balance period Pdc; In the DC balance period: apply the D pulse on this row of turntable driving; This D pulse is that frequency f dc is that 5kHz, dutycycle Ddc are 50%, amplitude Um is the high frequency direct impulse of 80V, and as shown in Figure 5, the pulse number Qdc of the D pulse that applies in the DC balance period is 200; Do not apply the positive voltage that amplitude Um is 80V on other row of turntable driving, as shown in Figure 6; Corresponding the listing of pixel that need be driven to the bright state of full impregnated on this row of turntable driving applies the E pulse, and this E pulse is identical with voltage direction, frequency, dutycycle, the pulse number of D pulse, and phase place is opposite, and is as shown in Figure 7; Corresponding the listing of pixel of vaporific shading state applies the F pulse when needing on this row of turntable driving to keep initial, and this F pulse is all identical, as shown in Figure 8 with voltage direction, phase place, frequency, dutycycle, the pulse number of D pulse;
Through above-mentioned sweep time, return ground phase and DC balance period after, this line scanning drives to be accomplished, each pixel that this row is corresponding all is rendered as corresponding show state according to the actual displayed demand.
From microcosmic angle:
The waiting period in: since all row and columns on all be applied in 0 volt of voltage; The voltage that is superimposed upon on all pixels is 0V, less than threshold voltage magnitude 50V, therefore; The arrangement form of the smectic phase liquid crystal molecule in mixolimnion 13 parts of all pixels correspondences does not change; Mixolimnion is not affected, and all pixels continue to appear vaporific shading state, waits for next step turntable driving.
In sweep time: for the pixel that this row that applies the A pulse and the row that apply the B pulse constitute, the voltage waveform that is superimposed upon on these pixels is that bidirectional pulse and the voltage difference on each moment are Um 80V, greater than threshold voltage magnitude Uth 50V; As shown in Figure 9, therefore, when voltage action time during less than 1 second; The arrangement form of the smectic phase liquid crystal molecule in pairing mixolimnion 13 parts of these pixels changes; Become regularly arranged form, at this moment, the long optical axis of smectic phase liquid crystal molecule is perpendicular to the plane of first, second conductive electrode layer 14,15; The ray refraction of each smectic phase liquid crystal molecule of incident does not produce acute variation; Light can freely see through this mixolimnion part, and on the macroscopic view, the mixolimnion that these pixels are corresponding partly presents the bright state of full impregnated; For the pixel that this row that applies the A pulse and the row that apply the C pulse constitute; The amplitude that is superimposed upon the voltage waveform on these pixels is 0V, and is less than threshold voltage magnitude Uth 50V, shown in figure 10; Therefore; The arrangement form of the smectic phase liquid crystal molecule in pairing mixolimnion 13 parts of these pixels does not change, and the mixolimnion part is not affected, and these pixels keep vaporific shading state; For the pixel that other row that apply 0V voltage and the row that apply the B pulse constitute; The amplitude that is superimposed upon the voltage waveform (negative-going pulse) on these pixels is Um 80V, and is greater than threshold voltage magnitude Uth 50V, shown in figure 11; But; The voltage waveform that is superimposed upon on these pixels is merely unidirectional pulse, and the smectic phase liquid crystal molecule in pairing mixolimnion 13 parts of these pixels only slight deflection can occur, and significant change does not take place arrangement form; The mixolimnion part does not receive tangible influence, is regarded as these pixels and continues the original state of maintenance; For the pixel that other row that apply 0V voltage and the row that apply the C pulse constitute; The amplitude that is superimposed upon the voltage waveform (negative-going pulse) on these pixels is Um 80V, and is greater than threshold voltage magnitude Uth 50V, shown in figure 12; But; The voltage waveform that is superimposed upon on these pixels is merely unidirectional pulse, and the smectic phase liquid crystal molecule in pairing mixolimnion 13 parts of these pixels only slight deflection can occur, and significant change does not take place arrangement form yet; Mixolimnion part does not receive tangible influence, is regarded as these pixels and continues the state that keeps original yet.
Returning in the ground phase: owing to all be applied in 0 volt of voltage on all row and columns; The voltage that is superimposed upon on all pixels is 0V; Less than threshold voltage magnitude Uth 50V; The arrangement form of the smectic phase liquid crystal molecule in mixolimnion 13 parts that therefore, all pixels are corresponding does not change the original state of all pixels continuation maintenances.
In the DC balance period: for the pixel that this row that applies the D pulse and the row that apply the E pulse constitute; The voltage waveform that is superimposed upon on these pixels is that bidirectional pulse and the voltage difference on each moment are Um 80V; Greater than threshold voltage magnitude Uth 50V, as shown in Figure 9, therefore; The arrangement form of the smectic phase liquid crystal molecule in pairing mixolimnion 13 parts of these pixels still is regularly arranged form; The long optical axis of smectic phase liquid crystal molecule is perpendicular to the plane of first, second conductive electrode layer 14,15, and the ray refraction of each smectic phase liquid crystal molecule of incident does not produce acute variation, and light can freely see through this mixolimnion part; On the macroscopic view, the mixolimnion that these pixels are corresponding partly continues to appear the bright state of full impregnated; For the pixel that this row that applies the D pulse and the row that apply the F pulse constitute; The amplitude that is superimposed upon the voltage waveform on these pixels is 0V; Less than threshold voltage magnitude Uth 50V, shown in figure 10, therefore; The arrangement form of the smectic phase liquid crystal molecule in pairing mixolimnion 13 parts of these pixels does not still change, and these pixels continue to keep vaporific shading state; For the pixel that other row that apply Um 80V positive voltage and the row that apply the E pulse constitute; The amplitude that is superimposed upon the voltage waveform (direct impulse) on these pixels is Um 80V; Greater than threshold voltage magnitude Uth 50V, shown in figure 11, still; The voltage waveform that is superimposed upon on these pixels is merely unidirectional pulse; Smectic phase liquid crystal molecule in pairing mixolimnion 13 parts of these pixels only slight deflection can occur, and significant change does not still take place arrangement form, is regarded as these pixels and continues the original state of maintenance; For the pixel that other row that apply Um 80V positive voltage and the row that apply the F pulse constitute; The amplitude that is superimposed upon the voltage waveform (direct impulse) on these pixels is Um 80V; Greater than threshold voltage magnitude Uth 50V, shown in figure 12, still; The voltage waveform that is superimposed upon on these pixels is merely unidirectional pulse; Smectic phase liquid crystal molecule in pairing mixolimnion 13 parts of these pixels only slight deflection can occur, and significant change does not equally still take place arrangement form, is regarded as these pixels and also continues the state that keeps original.
Do not use as outdoor display screen if display screen is not provided with backboard, the pixel of then vaporific lucifuge state is shown as black, and the pixel of the bright state of full impregnated is shown as white.If display screen is provided with the black backboard, the pixel of then vaporific lucifuge state is shown as white, and the pixel of the bright state of full impregnated is shown as black.
After pixel is shown as white or black; Just the voltage waveform that can remove row, lists; Pixel can continue to keep, and the maintenance of this show state does not need voltage to keep, promptly remove voltage waveform after; The luminous effect that pixel produces in the time of still can keeping the on-load voltage waveform, and the voltage signal of effect is just in order to change the arrangement form of smectic phase liquid crystal molecule.In the present invention, this state that does not need electricity to drive and keep luminous effect is called " multistable " or " quasistatic ".And this " multistable " is because additive has adopted the compound of band conductive characteristic; When electric signal applies; Ion in the compound of band conductive characteristic changes the generation to-and-fro movement according to electric potential difference; This motion can change the arrangement form of smectic phase liquid crystal molecule, and the smectic phase Liquid Crystal Molecules Alignment form after changing does not need the persistent movement of ion to keep, and is stable.
In the present invention; Apply the voltage waveform of being expert at, listing in sweep time and be the unidirectional voltage waveform; So just, reduce the implementation complexity of voltage waveform, reduced the driving difficulty, reduced cost; But the problem of thereupon bringing is: need appear and possibly have voltage difference (voltage integrating meter in sweep time is not 0) on those pixels of the bright state of full impregnated; In addition, in turntable driving each when row, do not have to have voltage difference (voltage integrating meter in sweep time is not 0) on the corresponding pixels of those row of turntable driving.And the long-term existence of voltage difference will cause the characteristic of smectic phase liquid crystal material to change, and entire display screen is flavescence gradually, even problem such as can not drive.Therefore, in the present invention, these problems are solved through adopting the voltage waveform that rationally is provided with in sweep time and increasing these means of DC balance period.Specify as follows:
For those pixels that are shown as the bright state of full impregnated; Through the mode of an integer pulse is set sweep time, as shown in Figure 9, make the voltage waveform that forms on these pixels can guarantee that in sweep time voltage integrating meter is 0 (promptly in sweep time; Positive pulse number on 0 level and the negative pulse number under 0 level are as many; Cancel out each other), and in the DC balance period, because the DC balance period has adopted the mode that an integer pulse is set equally; Therefore, the voltage waveform that forms on these pixels can guarantee equally that in the DC balance period voltage integrating meter is 0;
For those pixels that keep vaporific lucifuge state; Shown in figure 10, be always 0V owing to be superimposed upon the amplitude of the voltage waveform on these pixels, therefore; No matter it is 0 that sweep time or DC balance period, the voltage waveform that forms on these pixels all can guarantee voltage integrating meter;
When turntable driving delegation; For the corresponding pixel of those row that do not have turntable driving, (be that E, F pulse and D pulse are same type waveform, only phase place and D pulsion phase are together or on the contrary through increasing the DC balance period and the mode of those row of not having turntable driving in the DC balance period, each voltage waveform that lists rationally being set; And D pulse and A pulse also are same type waveform; And the pulse number that applies equates, in addition, does not apply the positive voltage that equates with A pulse amplitude Um on the row of turntable driving); Like Figure 11 and shown in Figure 12; Make in the DC balance period negative pulse number under interior 0 level of the positive pulse number on 0 level and sweep time as many, and this positive pulse equates with the area of this negative pulse, thereby positive and negative pulse is cancelled out each other; The voltage waveform that forms on these pixels has realized that in the whole cycle voltage integrating meter is 0, has realized the DC balance.
In the present invention; In order to guarantee the useful effect of DC balance period, need be provided with one between sweep time and DC balance period and return the ground phase, and this returns the duration tgnd of ground phase to keep the regular hour; Be generally greater than 1 millisecond, so that the high fdrequency component that possibly occur between sweep time and DC balance period is removed.Do not return the ground phase if this is not set, of short duration high frequency cls effect then can occur, the image of display screen is shown cause harmful effect.Those pixels that constitute with the row of the turntable driving not row corresponding with the pixel of the bright state of full impregnated are example, do not return the ground phase if be not provided with, and waveform promptly shown in Figure 11 has not had to return the ground phase; So, the waveform that forms on these pixels is shown in figure 13, and sweep time and DC balance period are directly joined; An of short duration high-frequency impulse has appearred on the point that links to each other of sweep time and DC balance period, though this high-frequency impulse has only one, this high-frequency impulse be bidirectional pulse and its moment amplitude reached Um 80V; Greater than threshold voltage magnitude Uth 50V; Therefore, it can play the effect of of short duration cls, and the normal refresh of display screen has been caused adverse effect.This shows that the setting of returning the ground phase is very necessary.
Pixel also can be shown as different gray states except being shown as black and white.In sweep time and DC balance period; Through control need be driven to the pixel of gray state corresponding list in the voltage waveform that applies with the corresponding row of this pixel on the identical pulse number opposite of phase place in the voltage waveform that applies with phase place, just can realize the demonstration of different gray states.Certainly, the voltage waveform that applies in the DC balance period should be able to offset with the voltage waveform that applies in sweep time, to reach the DC balance.
In reality, according to the demonstration needs, also can be mixed with a certain amount of dichroic dye in the mixolimnion 13, like this, the mixolimnion of smectic liquid crystal display screen just can switch between the bright and coloured shading of full impregnated.For the smectic liquid crystal display screen that has mixed dichroic dye; The smectic liquid crystal display screen identical (the physics realization principle of its pixel display image is similar with the smectic liquid crystal display screen of above-mentioned unmixed dichroic dye) of its scanning drive method and above-mentioned unmixed dichroic dye here repeats no more.
In the present invention, for unidirectional pulse, a voltage and the 0V voltage of the lasting Tn time formation that pulse is set amplitude U (not being 0) by having of a lasting Tp time, Tp+Tn=T.Like Figure 14, Figure 14 shows a pulse (pulse number is 1) of direct impulse, a positive voltage and the 0V voltage of the lasting Tn time formation that pulse is set amplitude U (not being 0) by having of a lasting Tp time, Tp+Tn=T.Threshold voltage Uth is for making the smectic phase liquid crystal molecule by driving the magnitude of voltage that arrangement form changes taken place, and it is to confirm according to the composition of mixolimnion and thickness, is generally more than the 5V.Sweep time Pscan, return ground phase Pgnd, DC balance period Pdc, initialization phase, the waiting period Pwait be the set time section of setting, for example, sweep time, Pscan was 5ms; Returning ground phase Pgnd is 3ms; DC balance period Pdc is 5ms, and the initialization phase is 1.5ms, the waiting period Pwait be 1ms.
Above-mentioned is preferred embodiment of the present invention and the know-why used thereof; For a person skilled in the art; Under the situation that does not deviate from the spirit and scope of the present invention; Any based on conspicuous changes such as the equivalent transformation on the technical scheme of the present invention basis, simple replacements, all belong within the protection domain of the present invention.
Claims (10)
1. smectic liquid crystal display screen unidirectional pulse driving method, it comprises: to all row of this smectic liquid crystal display screen driving of lining by line scan, it is characterized in that: each capable comprising the steps: of turntable driving
Step 1: sweep time: this row to turntable driving applies the pulse of line scanning phase, and this line scanning phase pulse is that frequency is that fscan, dutycycle are that Dscan, amplitude are the high frequency unidirectional pulse of Um; Other row to turntable driving not apply zero volt voltages; The corresponding row of pixel that on this row of turntable driving, need be driven to the bright state of full impregnated apply full clear state column scan phase pulse, and only phase place is opposite for this full clear state column scan phase pulse and the pulse of line scanning phase; The corresponding row of pixel of vaporific shading state apply vaporific lucifuge attitude column scan phase pulse when on this row of turntable driving, needing to keep initial, and this vaporific lucifuge attitude column scan phase pulse and line scanning phase pulsion phase are together;
Step 2: return the ground phase: apply zero volt voltage to all row and all row, the duration is tgnd;
Step 3: DC balance period: this row to turntable driving applies capable balance period pulse, and this row balance period pulse is that frequency is that fdc, dutycycle are that Ddc, amplitude are the high frequency unidirectional pulse of Um; Other row to turntable driving not apply the voltage that amplitude is Um; The corresponding row of pixel that on this row of turntable driving, need be driven to the bright state of full impregnated apply full clear state column balancing phase pulse, and only phase place is opposite with the pulse of row balance period in this full clear state column balancing phase pulse; The corresponding row of pixel of vaporific shading state apply vaporific shading attitude column balancing phase pulse in the time of on this row of turntable driving, need keeping initial, and this vaporific shading attitude column balancing phase pulse and row balance period pulsion phase are together;
Wherein: frequency f scan equals frequency f dc, and dutycycle Dscan equals dutycycle Ddc, and the pulse number Qscan of the line scanning phase pulse that applies sweep time equals the pulse number Qdc of the capable balance period pulse that the DC balance period applies.
2. unidirectional pulse driving method as claimed in claim 1 is characterized in that:
Said high frequency unidirectional pulse is a direct impulse; In said DC balance period, the amplitudes that apply to other row of turntable driving not are that the voltage of Um is positive voltage.
3. unidirectional pulse driving method as claimed in claim 1 is characterized in that:
Said high frequency unidirectional pulse is a negative-going pulse; In said DC balance period, the amplitudes that apply to other row of turntable driving not are that the voltage of Um is negative voltage.
4. like claim 1 or 2 or 3 described unidirectional pulse driving methods, it is characterized in that:
The frequency f scan of said high frequency unidirectional pulse is 1kHz≤fscan≤25kHz, and amplitude Um is 10V≤Um≤250V;
Amplitude Um is greater than threshold voltage magnitude Uth;
In sweep time, the pulse number Qscan that applies said high frequency unidirectional pulse is 1≤Qscan≤2000.
5. like claim 1 or 2 or 3 described unidirectional pulse driving methods, it is characterized in that:
The waiting period of also comprising before the said step 1; The waiting period in, apply zero volt voltage to all row and all row.
6. unidirectional pulse driving method as claimed in claim 5 is characterized in that:
Before the said driving of lining by line scan, also comprise the initialization step of removing images displayed on the smectic liquid crystal display screen, this initialization step is:
In the initialization phase, apply capable initialization pulse to all row, this row initialization pulse is the low frequency unidirectional pulse, applies the row initialization pulse to all row, only phase place is opposite for this row initialization pulse and this row initialization pulse.
7. unidirectional pulse driving method as claimed in claim 6 is characterized in that:
The frequency f init of said low frequency unidirectional pulse is 1Hz≤finit＜1000Hz, and amplitude Un is 10V≤Un≤250V;
Amplitude Un is greater than threshold voltage magnitude Uth;
In the initialization phase, the pulse number Qinit that applies said low frequency unidirectional pulse is 1≤Qinit≤500.
8. like claim 1 or 2 or 3 described unidirectional pulse driving methods, it is characterized in that:
The said duration tgnd that returns the ground phase is greater than 1 millisecond.
9. like claim 1 or 2 or 3 described unidirectional pulse driving methods, it is characterized in that:
The initial phase of the capable balance period pulse that applies in the initial phase of the line scanning phase pulse that applies in said sweep time and the said DC balance period is identical or different.
10. like claim 1 or 2 or 3 described unidirectional pulse driving methods, it is characterized in that:
Said line by line scan to drive be in sequential scanning drivings line by line, backward turntable driving, fractional scanning driving, two fens algorithm turntable driving or the out of order at random turntable driving any.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US9417470B2 (en) | 2011-09-14 | 2016-08-16 | Cambridge Enterprise Limited | Driver circuit |
| CN106782355A (en) * | 2016-07-15 | 2017-05-31 | 苏州汉朗光电有限公司 | A kind of self-adaptation drive method of smectic liquid crystal screen |
| CN109272952A (en) * | 2018-10-22 | 2019-01-25 | 信利半导体有限公司 | The driving method and device and bistable liquid crystal devices of bistable liquid crystal |
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| US5151803A (en) * | 1989-01-09 | 1992-09-29 | Matsushita Electric Industrial Co., Ltd. | Pixel-gap controlled ferroelectric liquid crystal display device and its driving method |
| CN1287626A (en) * | 1998-10-22 | 2001-03-14 | 西铁城时计株式会社 | Ferroelectric liquid crystal display, and its driving method |
| CN101840681A (en) * | 2010-04-01 | 2010-09-22 | 汉朗科技(北京)有限责任公司 | Rapid scanning driving method for smectic liquid crystal display screen |
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| US5151803A (en) * | 1989-01-09 | 1992-09-29 | Matsushita Electric Industrial Co., Ltd. | Pixel-gap controlled ferroelectric liquid crystal display device and its driving method |
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| CN1287626A (en) * | 1998-10-22 | 2001-03-14 | 西铁城时计株式会社 | Ferroelectric liquid crystal display, and its driving method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US9417470B2 (en) | 2011-09-14 | 2016-08-16 | Cambridge Enterprise Limited | Driver circuit |
| CN106782355A (en) * | 2016-07-15 | 2017-05-31 | 苏州汉朗光电有限公司 | A kind of self-adaptation drive method of smectic liquid crystal screen |
| CN106782355B (en) * | 2016-07-15 | 2019-03-12 | 苏州汉朗光电有限公司 | A kind of self-adaptation drive method of smectic liquid crystal screen |
| CN109272952A (en) * | 2018-10-22 | 2019-01-25 | 信利半导体有限公司 | The driving method and device and bistable liquid crystal devices of bistable liquid crystal |
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| CN102622972B (en) | 2013-09-04 |
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