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TFT_ LCD driving principle

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TFT LCDLCDmanagement(one)


the first two times to introduce to you the basic principles of LCD operationmanagement,that is a special feature for liquid crystal itselfsex,andTFT LCDthe operating principle of its own structureShao.this time we needlepairTFT LCD's overall system surfaceShao,is to introduce its driving principleShao,and its driving principle is still due to some architectural differences,but not.First of all, let's introduceonCs(storage capacitor)Storage capacitor architecture does not,different drive system architecturesmanagement.

Cs(storage capacitor)Storage Capacitor

In general, there are two most common storage capacitor architecturesspecies,respectivelyisCs on gateandCs on commonthese twospecies.these two, as the name implies, can be knownroad,it is that the storage capacitor is beneficialgaterouting oriscommonrouting to the last article,I mentioned,storage capacitor is mainly used to make the charged electricitypressure,can keep it until the next time the picture is we have to be likeinCMOS,use different layers of walkingline,to form parallel plate electricity.andinTFT LCD,uses display electrodesandgaterouting oriscommongoline,,to make stored electricityCs.


1are the two storage capacitor holdersstructure,we can clearly know from the figureroad, Cs on gatebecause it is not necessarylikeCs on commononesample,need to add an additionalcommongoline,so its openingrate(Aperture ratio)will compare.and the opening rate is large,is an important factor affecting the brightness and design of panels.element., so most of the panel designs today makeCs on gate.butonCs on gate,its storage capacitor is the next onegatetrace and display electrode.(see2Cs on gateandCs on commonroad)andgategoline,, as its name implies, is to receive everyTFTgateendline,is mainly aboutisgate driver,to fightonTFTletTFTto charge and discharge the display electrode., so the next onegategoline,the output voltage to turn on the next oneTFT,will affect the large storage voltage on the storage capacitor., but because of the nextgaterouting to turn off.short,(1024*768resolutionrate, 60Hzthe update frequency panelsaid.onegaterouting time is aboutis20us,The time when the display screen is updated is approximatelyis16ms,so relativewords,impacts include.), so the next onegaterouting offclosed,return to the original electricitypressure,Csthe electricity of the storage capacitorpressure,will also return to why,, most storage capacitor designs are adoptedCs on gatecause.


oncommongoline,we also need to introduce one by the way here..from2now,No matter what kind of storage capacitor rack you usestructure, Clcare respectively connected to the display electrodeandcommon.since the liquid crystal is filled with the upper and lower pieces of glassroom,and display electrodeandTFTare all located in the same piece of glass.,commonelectrode is obviously located in another piece of one,parallel plate electricity formed by liquid crystalClcis the display electrode of the upper and lower glassandcommonelectrode shape.and bitonCsstorage capacitorcommonelectricitypole,is another use of the walk on the same glass as the display electrodeline,hereandClccommonelectrodes are different,it's just that they end up being connected to the same voltage.

the circuit architecture of the whole panel


from3, we can see the equivalent electricity of the whole panel.road,each of themTFTandClcandCs,represents a displayedpoint.and a basic display listyuanpixel,requires threepoint,tableRGBSanyuancolor.with one1024*768resolutionTFT LCDsaid,1024*768 *3such a point combination.the general structure of the whole panel is thissample,and then borrow by such3gate drivershape,TFTon,so that the whole rowsource driverdisplays an entire row at the same timepoint,charge to the electricity they needpressure,displays different grayorder.when this line is fully charged, gate driverturn off the voltageclosed,then the next linegate driverwill hit the voltageon,by the same onerowsource drivercharge and place the display points in the next this order,when the display of the last line is filledpoint,, he came back and started charging from the first row.electricity.with one1024*768 SVGAresolution LCDsaid,totalhave768linegategoline,andsourcerouting is required.1024*3=3072.are mostly used in general liquid crystal displays.is60Hzupdate frequencysaid,the display time of each screen is aboutis1/60=16.67ms.due to the composition of the pictureis768linegategoline,so assigned to eachgatetrace is aboutis16.67ms/768=21.7us., so in3 gate driver,we can watch,these waveforms are width after widthis21.7uspulsewave,Open each row in orderTFT.andsource driverinhere21.7us,sutrasourcegoline,charge and discharge the display electrode to the required electricitypressure,to show the corresponding ashorder.


because liquid crystal molecules also have a specialsex,is that it cannot be fixed at a certain voltage all the timechange,Otherwise, it will take a long time.,even if you cancel the voltagedrop,liquid crystal molecules will break due to their characteristicsbad,and can no longer respond to changes in the electric fieldmovement,to form different ashesorder., so every once in a whileroom,must restore the voltageshape,to prevent the characteristics of liquid crystal molecules from being brokenbad., but if the picture is notmovement,that is to say, when the screen always shows the same gray scaleOffice?So the display voltage in the LCD is divided into two polessex,one is positivesex,and the other is the negative electrodesex.when the voltage of the display electrode is highoncommonelectrode voltage,is called positive electrodesex.and when the voltage of the display electrode is lowoncommonelectrode,is called negative electrodesex.whether positive or negativesex,will have a set of gray with the same when the absolute value of the pressure difference between the upper and lower layers of glass is fixed,regardless of the voltage of the display electrode,oriscommonelectrode,is exactly the same..but these two situations,the turn of liquid crystal molecules is complete phase,can also avoid the above when the liquid crystal molecules turn and are fixed in one direction all the time.,are broken.bad.issaid,When the display screen has not moved,we can still use the positive and negative polarity to keep crossingreplacement,movement,at the same time, liquid crystal molecules are not when you see the LCD screen is stillmovement,is constantly changing.,and one of the liquid crystal molecules is constantly going this way,another turn in the opposite direction!


4is the transformation of various polarities of the panel,Although there are so many conversion parties,they have one in commonpoint,change the pole the next time the screen data is frequencysaid,isevery16ms,Change the pole of the screen,for the same pointwords,its polarity is constantly changing.and whether adjacent points have the same polesex,, it can be determined according to different polarity conversion methods..firstisframe inversionit all adjacent to the whole picturepoint,all have the same polesex.androw inversionandcolumn inversioneach has the same pole on the adjacent row and additionindot inversion,is the four points adjacent to each point.point,is a different polesex.Finallyisdelta inversionbecause of its different arrangementsample,so it isRGBformed by three pointspixelas a basic orderbit,whenpixel,itanddot inversionis very similar,is everypixelis adjacent to yourself up and down, left and right.pixel,uses different polarities to display.




5and6is two differentCommonelectrode,5Commonelectrode is fixed all the time.,the voltage of the display electrode is not according to its gray scale,keep changing up and downmovement.5is256Gray Scale Display Electrode Waveform Change,V0this gray scalewords,If you want to display it on the panelV0this gray scalewords,, the voltage of the display electrode must be very high at one time.,but another time it was very complicated?is just like the reason we mentioned earlier.sample,is to keep the liquid crystal molecules from turning at the same time.,leads to permanent destruction of physical therefore differentframe,V0this gray scalesaid,its display electrodeandcommonelectrode is fixed,so its gray scale has never just a bitinClcpressure,is positive once,call it positive electrodesex,while the other was negative,call it negative electrodesex., in order to achieve the goal of changing polarity,we can alsoletcommonvoltage keeps changingmovement,can also be achievedletClcis fixed.change,and gray scale will not changefruit,and this partymethod,is6the waveform change displayed.this method is justwillcommonelectricitypressureonce,a small change.of course,it must be higher than the maximum voltage in the gray scale,voltage is small, it is smaller than the smallest voltage in the gray scale.line.and the voltage of each gray scale is the same5sample,still needs big and small changes..

these two differencesCommonthe driving mode has the greatest impactissource driver's make.7Commonthe penetration rate of the voltage drive modesaid,we can watch,whencommonelectrode is fixed,display electrodepressure,needdacommontwice the electrode voltage.and display electrode voltage increasesupply,is fromonsource driver.with Figure 7commonif the electrode voltage is fixedon5volt'swords,source drivercan provide


scope is required10volt.butfruitcommonelectrode varieswords,falsemakecommonelectrode voltage maximumis5volt,source driveris onlyis5Volt is fine.source driverdesign and manufacturesaid,requires higher voltage operating rangeenclosure,process and circuit will increase,costs will also be increased.

panel polarity conversionandcommonElectrode Driving Mode

Not all panel polarity conversion methods can be used with the above twospeciescommonelectrode.whencommonelectrode voltage is fixed,You can use all panel polarities..butfruitcommonvoltage varieswords,, the panel polarity conversion can only be selected.frame inversionandrow inversion.(seetable1)issaid,if you want to makecolumn inversionorisdot inversionwords,you can only choosecommondriver with fixed electrode voltage.why?we mentioned beforecommonelectrode is located in a glass different from the display electrode.,in actual production,in fact, this whole piece of glassiscommonelectricitypole.issaid,all displays on the panelpoint,themcommonvoltages are all connected followedongate driveris performed by using the same row.haveTFTon,letsource driverto chargeelectricity,and all displays in this linepoint,itcommonelectrodes are all connected together,so if you are the choicecommonelectrode voltage is variablewords,cannot be in onelineTFT,to show both positive and negative polarity at the same time.andcolumn inversionanddot inversion,the display point on a row,requires each adjacent point to have different positive and negative whycommonelectrode voltage variation can only be appliedonframe inversionandrow inversion.andcommonthe fixed electrode voltage,do not have these limitssystem.becauseitscommonvoltage is always fixed,onlysource drivercan charge the voltageratiocommonis,ratiocommonthe voltage is small, the negative electrode can be,Institutecommonthe fixed electrode voltage,can be applied to various panel polarity conversion methods.


panel polarity conversion method

can be usedcommonelectrode driving mode

Frame inversion

Fixed and Changed

Row inversion

Fixed and Changed

Column inversion

Only fixedcommonelectrode voltage

Dot inversion

Only fixedcommonelectrode voltage

Comparison of Polarity Transformation of Various Panels

LCD displays commonly used on personal computers now,the panel polarity conversion method used,Most of themisdot inversion.why?No causeit,only becauseisdot inversionis relative to other panel polarity conversion methods.,to come..table2is a comparison of various panel polarity conversion methodstable.InstitutepredicateFlickerelephant,is when you look at the LCD screen,you will feel the picture flickering.awareness., it is not intended to make the display screen light up and off to make the visual effect of flashing.fruit,is because the gray scale of the displayed picture is updated every time.,will change slightlymovement,makes people feel the picture flashing.Shuo.this kind of situation is most likely to happen when makingframe inversion,causeisframe inversionthe whole picture is the same polesex,when the picture is positive this time,next time the whole picture will become negativesex.if you are makingcommonvoltage is fixedmovement,andcommonvoltage.(see8),


at this time, the same gray-scale voltage of the positive and negative polarity will be different.don't,of course, the feeling of gray scale is differentsample.keeps switching screens,due to positive and negative polarity, the pictures alternatenow,you will feelFlickerstoragein.and the polarity of other panels,thisflickerelephant,but because it doesn'tlikeframe inversionis the simultaneous conversion of the entire,only one line or onecolumn,even a point changes polarity.the feeling of human eyessaid,will be more unknown.oncrosstalkelephant,it refers to the adjacent pointsroom,the data to be displayed will affect,so that the displayed screen will have incorrect appearance..crosstalkphenomenonspecies,As long as the polarity of adjacent points is differentsample,can reduce the incidence of this phenomenon.combining these characteristicssex,we can knowroad,why do most people makedot inversion.


panel polarity conversion method



Frame inversion


is easy to occur in both vertical and horizontal directions.

Row inversion

is not obvious

horizontal direction is easy to occur

Column inversion

is not obvious

is easy to occur in the vertical direction.

Dot inversion

almost none

is not easy to happen.


panel polarity conversion,also has different effects on power consumption.ring., but it needs to consider its collocation in terms of power consumption.commonelectrode driver.generallysaidcommonif the electrode voltage is solid,its drivemovementcommonelectrodes will be compared., but because ofcommonvoltage fixing modesource driverits required voltage comparison,insteadinsource driverwill be compared.But if you use the samecommonelectrode driver,insource driverof power consumptionsaid,must consider the variable frequency and large variable voltage of its output voltage..generallysaid,In this case, source driverconsumptionelectricity,willhavedot inversion > row inversion > column inversion > frame inversionshape.but nowondot inversionsource driveris mostly to makePNOPinsteadlikerow inversionis to makerail to rail OPinsource driverOPwill be compared.means thatonsource driver,has the highest frequency of output voltage variation(maximum variable voltage connectionnear10volt,androw inversionpanels are mostly usedcommonthe side of electrode voltage variation,itssource driveris onlyhave5volt,power consumption will be compared),dot inversionpanel has been greatly reduced..This is why most LCD monitors makedot inversion. 

TFT LCDLCDmanagement(II)


ContinuedTFT LCDLCDmanagement(one)

last time, I introduced to you about the storage capacitor frame in the driving principle of LCD.structure,panel polarity conversion,andcommonvoltage.this time we continue the last time,continue the needlepairfeed throughelectricitypressure,and the principle of second-order driveShao.simplesaidFeed throughvoltage is mainly caused by parasitic capacitance on the panel,and the so-called third-order drive principle is the solution developed to solve this problem.,However, this time we will only introduce the second-order drivemovement,as for the third-order drive or even the fourth-order drive, it will be left for the next the agencyShaofeed throughvoltage,let's first explain the drive systemgate drivertiming.



we are common1024*768resolution screenscreen,is what we usually callisSVGAresolution screenscreen.its composition, as its name implies, is1024*768=786432pixelto form the number of liquid crystal displaysaid,1024*768 *3point(multiplication3is because onepixelneeds bluecolor,greencolor,Three red dots to group.)to display a usually in the panel gaugerow,divide a planeX-Yaxissaid,inXon the axishave1024*3=3072column.here3072column8384outchannelsource driverto be responsible for pushingmovement.andinYaxis,willhave768line.here768line,3256outchannelgate driverto drivemovement.1isSVGAresolutiongate driveroutput waveformtiming.gate 1~768respectively768gate driver's lossout.SVGArate,60Hzscreen update frequency.,oneframeis aboutis16.67 ms.pairgate1said,its startup time period is the sameis16.67ms.and inhere16.67 msroom,respectivelyletgate 1~768768outputline,Open and then close in orderclosed.So the time allocated to each line is onlyhave16.67ms/ every onegate driverThe opening time is relative to the wholeframeis very short,and in this short opening time,source driverthen charge the corresponding display electrode to the required electricitypressure.

and the so-called second-order drive ismeansgate drivervalue,one is to turn on the electricitypressure,one is to turn off the electricitypressure.and rightoncommonvoltage,whenever and wheneverplace,voltage is fixed.but yesoncommonVoltage Variation,in eachframegate1Open,must change the voltage by onetimes.why do you want to use these output voltagestiminghas been introduced once?because we're going to discussfeed throughelectricitypressure,it is mainly due to the change of other voltages on the panel.,through parasitic capacitance or storage of electricity,affects the correctness of the display electrode voltagesex.inLCDpanelhave3,respectivelyisgate drivervoltage change,source drivervoltage change,andcommonvoltage change.and the one with the greatest impact isisgate drivervoltage change(sutraCgdorisCs),andcommonvoltage change(sutraClcorisCs Clc).


Cs on commonArchitectureandcommonvoltage fixedfeed throughvoltage

we just mentioned,causedhavefeed throughvoltage.andincommonVoltage,madefeed throughvoltage is onlyhavegate driver.in2,is the display electrode voltage factorisfeed throughvoltage shadowring,.in Figure,Please notegate driveris openedroom,relative to eachframetime ratio is we are in order to be able to explain carefully everyframemovement,sowillgate driverOpen Time Paintings.please rememberlive,correctgate driverThe opening time is as follows1Institute,needs to be in oneframe,will768gate driverrouting is everygatetrace is turned onroom,is relative to oneframeroom,is very short.


whengatewiring opens or closesroom,voltage changes are the most intense,will be abouthave30 to 40volt,Cgdparasitic electricity,affects the electricity of the display electrodepressure.in3,we can watchCgdthe presence of parasitic capacitance.itsCgdhair,and GeneralCMOScircuit onesample,is a bitonMOSgateanddrainend.but becauseinTFT LCDpanelgategate driveroutput travelline,, so onceingate driveroutput line has changed fiercely.,will affect the electricity on the display electrodepressure.in2,whenFrameNgaterouting is open,will produce an upwardfeed throughvoltage to display electrode.but at this timeongatethe edge where the trace is opened,source driverwill start charging the display electrodeelectricity,so even if the initial voltage is notpair(causeisfeed throughVoltagering),source driverwill still charge the display electrode to the correct electricitypressure,the impact will not be too great..but ifwhengatetrace is closed,onsource driverno longer charge the display electrodeelectricity,Institutegate driveris turned offdrop(30 to 40volt),will passCgdparasitic electricityfeed throughto the display electrode,causes the display electrode voltage to have onefeed throughvoltagedrop,affects the correctness of gray scale displaysex.and thisfeed throughvoltage is notlikegatetrace is turned onfeed throughvoltage onesample,only affects,Due to thissource driverno longer charge and discharge the display electrodeelectricity,feed throughvoltage drop will affect the electricity of the display electrode.pressure,until nexttimesgate driverthe voltage on the line is turned on again., so thisfeed throughvoltage on the gray scale of the display screenring,the human eye can clearly feel its existence.andinFrame N1,just startedwhengate driverwiring openedroom,will also produce an upward view of the display electrodefeed throughelectricitypressure,but at this timeongatethe opened edge,source driverwill start charging the display electrodeelectricity,So this upfeed throughvoltage will not be too long..whengaterouting is closed again,downfeed throughvoltage will lower the voltage of the negative display electrode.drop,and the affected negative polarity display voltage will be maintained until the nexttimesgateis turned on again., so the wholesaid,display electrodepressure,willratiosource drivershall be.and the reduced voltage is just rightisgatelineCgdfeed much this voltage is?


in4,we determine that the charge is not,can be derivedoutfeed throughvoltageis(Vg2-Vg1) * Cgd / (Cgd Clc Cs).falseCgd=0.05pF,andClc=0.1pF, Cs=0.5pFandgatethe voltage of the trace from on to offis-35volt'swords.feed throughvoltageis-35*0.05 / (0.05 0.1 0.5) = 2.69volt.Generally, the voltage difference between one gray scale and another gray scale is only abouthave3050 mVand(this is6 bitresolution andwords,ifis8 bitresolution onlyhave35 mVand).causethisfeed throughvoltage affects gray scale very seriously..normal whitepolarizing plate configurationsaid,the grayscale that will cause positive polarity will be higher than originally expected.bright,, the gray scale of the negative electrode type will be higher than originally just rightfeed throughvoltage is consistentsex,so we just havewillcommonthe voltage is adjusted downward, that ismay.from2,correctioncommonvoltage and originalcommonvoltage is just the same.onfeed throughelectricitypressure.

Cs on commonArchitectureandcommonvoltage variationfeed throughvoltage

5isCs on commonandcommonvoltage fluctuationshape,dueitscommonvoltage is with eachframeand change,Thereforeandcommonthe waveform with fixed voltage is compared.its productionfeed throughthe voltage source will be increased by one more,theniscommonvoltage.herecommonvoltage,sutraClc Cselectricity,will affect the electricity of the display electrodepressure.and due to the wholeLCDAll display points on the panelClcandCsare all connectedcommonelectricitypressure,so onecommonvoltage has changed,is affected by all of the entire frontsurfacegatevoltage changes are differentis,gatevoltage changes affect only the display points of a whole line..NoCommonvoltage change has an impact on the voltage of the display electrodering,but no influence on gray scalelikegatevoltage changes.say?If we use the same capacitance parameters as beforevalue,6derived public,leave againCommonvoltage0volt change5volt,commoncaused by voltage changesfeed throughvoltageis(5 -0)*(0.1pF 0.5pF) / (0.05pF 0.1pF 0.5pF) = 5*0.6/0.65=4.62volt.although the display electrode adds so much electricitypressure,iscommonelectrode also increased5volt.ThereforeinClctwo,is also the two liquid crystals,see the pressure difference change,onlyhave4.62-5=0.38Volt and.followedgatecaused by changes in wiring voltagefeed throughelectricitypressure2.69volts are much smaller by comparison.,so the influence on gray scale is much smaller.and because of itfeed throughvoltage is symmetricalsex,NolikeGategenerated by routingfeed throughvoltage is always going,so just the same display pointsaid,on gray scale performance in vision will be compared.of course,comparison,but because of the wholeLCDpanel768said, commonvoltage changes occurpoint,andgateThe time interval for routing is different.,So the grayscale effect on the whole picture is different.such a,to improve the picture.,is whycommonVoltage Variation,is less and less used by people..


Cs on gateArchitectureandcommonvoltage fixedfeed throughvoltage

7isCs on didn'thavecommoncaused by voltage changesfeed throughelectricitypressure,it is only made upongatecaused by voltage changesfeed throughelectricitypressure.but itandCs on commonis differentis,gatecaused by voltage changesfeed throughvoltage,one is oneselfgaterouting opensCgdgenerationfeed throughelectricitypressure,the other is the previous onegaterouting is open,sutraCsgeneratedfeed throughelectricitypressure.sutraCgdfeed throughvoltage is the same as the situation discussed earlier.,will not be mentioned here..but sutraCsfeed throughelectricitypressure,is the causeisCs on gateoff,3Institute. Cs on gate's rackstructure,the other end of its storage capacitor is not connectedcommonelectricitypressure,but received the previousgategoline,, therefore, in our casegaterouting is open,is the firstgaterouting is open,in the firstgatetrace,will passCsfor our display electrodefeed throughelectricitypressure.according8's public,Apply the previous capacitance parameters at the same timeandgatevoltage changevalue,we can get thisonefeed throughvoltage is aboutis35*0.5pF/(0.5pF 0.1pF 0.05pF)=26.92volt.thisfeed throughvoltage is very large,but the current onegaterouting is closed,herefeed throughvoltage will also disappearloss.and the formergaterouting from on to offclosed,SVGAresolution screensaid,onlyhave21.7ustime relative to oneframeroom16.67msis very short.Furthermore, the current onegateroutingfeed throughVoltage Affects Display Electrode,this one of usgateroute also went with it.on,source driverimmediately charge and discharge the voltage of the display electrode to the desired targetvalue.from the results of this kind,Previousgatetrace,ash for our display electrodeorder,has little therefore rightonCs on gateandcommonthe driving mode with fixed voltagesaid,still has the greatest impactisgateon-line voltage variationCgdgenerationfeed throughelectricitypressure,and its solution is the same as the previous onessample,just needwillcommonthe voltage is adjusted downwardmay.

Cs on gateArchitectureandcommonvoltage variationfeed throughvoltage


9isCs on gateArchitectureandcommonvoltage variationfeed throughvoltage waveform.such a framestructure,just beforesurface3point,thenisgateroutingCgdfeed throughelectricitypressure,and the previousgateroutingCsfeed throughelectricitypressure,andCommonvoltage variationClcfeed throughelectricitypressure.can be imaginedknowledge,, almost no one uses this architecture in actual panel design..andhere4The most commonly used architectureisCs on gateArchitectureandcommonvoltagestructure.because it only needs to consider the classicsCgdfeed throughelectricitypressure,andCs on gatearchitecture can get a larger opening rate.

Second-order drivemovement(Two level addressing)

please pay attention:

TFT LCDLCDmanagement(3)

TFT LCDLCDmanagement(3)


last time I introduced to you the second-order driver of LCDmanagement,and Causeisfeed order to solve these problemselephant,then there is a third-order drive or even a fourth-order drive.meter.Next, let's focus on the principle of third-order drive.Shao.

the origin of the third-order drivemanagement(Three level addressing method)

Second-order Drive,although there are various differencesfeed throughelectricitypressure,, but the biggest impact is still on the economyCgdgeneratedfeed throughelectricitypressure.also needs to be adjusted in the second-order drive.commonelectricitypressure,to improve gray scale products.butonClcis not a fixed parameter,tunecommonvoltage to improve image quality..Therefore, there is a third-order drivemeter,expectations need not changemovementcommonvoltage,willfeed throughvoltage to compensate back.

third-order drive is this,utilization sutraCsfeed throughelectricitypressure,to compensate forCgdgeneratedfeed also because of the need for profitCsto supplementcompensation,Therefore, the third-order drive method can only be used in the panel architectureisCs on gate.1is the third-order drivemovementgate drivervoltageshape,we can know from this third-order drive waveformroad,the waveform of the third-order drive is different from the second-order driveis,itgate driverdrive waveform,will have three different kinds of electricitypressure.whengate driverOff,will pull the voltage to the lowest level of electricity.pressure,wait until the next onegater driverrouting is also closed,pull the voltage again.and this pulled back electricitypressure,is to compensate for the next linefeed throughelectricitypressure.issaid,eachgate driverrouting is closed,sutraCgdgeneratedfeed throughelectricitypressure,the voltage is pulled back by the previous trace,sutraCsgeneratedfeed throughvoltage to made up by pulling back the voltagecompensation,how to calculate the pull-back voltage?last time we mentionedfeed throughVoltage,we can calculate the required electricity according to the last formulapressure:

sutraCgdFeed throughelectricitypressure= (Vg_high-Vg_low) * Cgd / (Cgd Clc Cs) ; Vg_highandVg_lowrespectivelyisgate driverwiring on and offpressure.

sutraCsFeed throughelectricitypressure= (Vp2-Vp1) * Cs / (Cgd Clc Cs) ; Vp2andVp1are respectively the previousgatethe electricity before and after the wiring is pulled backpressure.

If you need to offset each otherelimination,sutraCgdFeed throughvoltage needs to be equalsutraCsFeed the voltage to be pulled backisVe=Vp2-Vp1=(Vg_high-Vg_low) * Cgd / Cs,and from1roadVg_high-Vg_low= Vg Ve, so the electricity that needs to be pulled backpressureVe= (Vg Ve) * Cgd / Cs,alsoisVe= Vg * Cgd / [Cs-Cgd].

derived from the above formula,we found that althoughClcshadowringfeed throughvoltage,but by the third-order drive, Clcwill not be when we are in the panel processandgate drvieris determined,can accurately calculate the required pull-back voltage.



2is a schematic of the voltage distribution of the third-order drive.we can see that the leftmost one issource drivercloth,this is the original shape of the voltage charged by the display electrode.and the middle voltage scorecloth,means that the display electrode is subjected to warpCgdfeed throughVoltage.In general, the second-order drive is only here.,, so it needs to be repaired.positivecommonvoltage,in order to use less gray-scale distortiondegree.and the third-order driveCsfeed throughthe influence of voltageshape,can be seen from the rightmost voltage this time,just take it and pull it backpressureVe,, you can take the originalCgdfeed throughvoltagecloth,compensation to the leftmost voltage distribution onesample,in this way, there is no need to repair it again.positivecommonvoltage.


3is the voltage waveform of the third-order I said earlier,Because the third-order driver needs to use the previous onegate driverrouting to make upcompensation,so you can only useonCs on gate's rackstructure.and due to the voltage compensation off, commonvoltage..in3,genusongate drivervoltagesspecies,one is the firstgate drivervoltage waveshape,Dashed lines are used to list the table.., the solid line indicates the voltage waveform of the display electrode that we want to discuss.gate driverwiringpressure.we can know from this graphroad,solid linegate driverrouting is closed,meetingCgdproduces onefeed throughelectricitypressure,and this downward voltage shiftquantity,in the firstgate drivertracesutraCsgeneratedfeed throughvoltage influence,can restore the display electrode to its original voltage levelbit.beforegate driverroutingCsFeed throughvoltage,that is in the first placegate drivergenerated when the trace is turned onfeed throughelectricitypressure,this voltage value is very high,but due to its influenceroom,is relative to the wholeframesaid,quiteshort,will not have much influence on the display screen.ring.
Figure 4 shows the use of a third-order drive needle.pairgate drivertrace voltage variationfeed throughVoltage Display Electrode Voltage Waveform More different from Figure 3is,this figure takes into accountwhengate driverthe trace voltage is pulled backCgdfeed throughelectricitypressure.originally pulled back the voltage to compensate for the next one.gate driverthe online display electricitypole,but its side effect is alsopairgate drivertrace produces a shadow.ring., so the design test of pulling back the voltagequantity,does not compensate all voltages back at once,instead, use it twice.feed throughvoltage the last timegate driverroutingCsfeed throughvoltage to make upcompensation,once by displaying the location of the electrodegate drivergoline,its pull-back voltage warpCgdfeed throughvoltage to make upcompensation.


to sum upsaid,uses a third-order drive compared to a second-order drivesaid,can not be adjustedcommonvoltage can be gramsclothingfeed throughVoltagering.but also can be avoidedonClcquestion.but compared with the fourth-order driver to be introduced below,it still needs to use a higher output voltagesource driver.Next, the fourth-order drivemovement,itincommonthe condition that the voltage is fixed,does not need to use high voltage outputsource driver,can achieve the result of separate positive and negative voltage.

the origin of the fourth-order drivemanagement(Four level addressing method)

5is a fourth-order drivemovementgate drivertraceshape.we can see that we are responsible for positive and negative polarity.gate driverthe wiring voltage is responsible for negative polaritygate drivertrace voltage is turned off at voltage,will pull down to a level lower than the voltage normally turned off.bit,wait until the voltage of the next trace is turned off,then pull the voltage back to the standard of the general off voltagebit.and responsible for positive polaritygate driverthe wiring voltage is when the voltage is off,voltage did not reach the normally closed voltage level in one breath.,but wait until the next onegate driverrouting is closed,then pull down the voltage to the normally closed voltage levelbit.and the voltage levels of these two polarities are quasi-totalhave:turned on electricitypressure,off electricitypressure,bit higher than off voltage,and electricity lower than the shutdown voltagepressure,species.this is why it is called the fourth-order drivecause.from Figure 5look,we will sendnow,the same onegate driverthe online display electricitypole,must belong to the same display polesex,is not positivesex,is the negative electrodesex.Therefore, using a fourth-order drive can only makeline inversion.but this one,heeldot inversionthe drive mode of the panelsaid,the quality of the display screen will change even more, flickerandcross talkwill be clearer.This is also why the fourth-order driver is rarely used,Although it can use a lower drive voltagesource driverbut itgate drivercomplexity increases,and the picture qualitydrop,(of course,want the fourth-order drive panel to makedot inversionis not impossible,Just need to change the panelTFTThin Film Transistor,and increase the memory in the display controller,to store two at the same timegate driverthe number of all display electrodes on the line,the complexity of the entire hardware will be even greater,costs will increase.)is better than makingline inversionandcommonvoltage changes.


the fourth-order drive principle is simplesaid,is to use the previousgate driverroutingCsfeed throughelectricitypressure,raises the voltage of the display electrode to a very high level of electricity when it is positive.pressure,while in negative polaritywill display the electricity of the electrodepressure,pull down to a very low electricitypressure,so as to give the voltage of the display electrode to the positive or negative voltage level one, source driveris not,, however, it can simultaneously give positive and negative display electrode voltages..6is a schematic of the voltage distribution of the fourth-order drive,The leftmostissource driverOutput Voltage RangeWai.whether it is positive paintingsurface,or negative paintingsurface,all use the same output voltage therefore used for fourth-order driverssource driverits output voltage range is more than normalsource driversmall.and6is the recipientgate driverrouting is closed,sutraCgdfeed throughvoltageWai.and6is the final display voltage range with positive and negative polarity.enclosure.we can see from the figureroad,because of sufferingCgdfeed throughvoltage shadowring,if you want to separate the positive and negative voltage rangeswords,voltage range for positive polarityWai,will be compared,and its upward lifting of electricitypressure,is from the previousgate drivethe wire voltage is pulled upCsfeed throughvoltage to form.because of its required voltage comparison,, so last timegate driverpressurewill also compare.and the shape of the display voltage range for negative polarity,also uses the previousgate driverthe voltage change on the different from the positive electrode display electrode voltageis,what it needs is a drop-downfeed throughelectricitypressure,to form a negative display electrode voltage rangeWai.the pull-down electricity it needspressureis compared with the positive pull-up voltage.However, for the adjusted positive and negative polarity display voltage rangesaid,they are relativeoncommonvoltage should be onesample,so for the positive and negative polarity of the same gray scalepressure,the screen displayed will only be one.from the whole6said,we can sendnow,paironsource driveroutput powerpressure,as mentioned earlier,does not need to have positive and negative two different polarity display modelsWai.just use the previousgate driverthe voltage change of the trace to help form the two voltage ranges of positive and negative polarity, namelymay.


As for the voltage change wave on the display electrodeshape,we can use7and8to explain the original voltage changemanagement.7is the waveform change of negative electrode display electrode voltage,we can see from the figureroaddisplay electrode voltagefromsource driverto charge,will undergo three more voltage Benbodygate driverwiring voltage off,sutraCgdgeneratedfeed throughvoltage shadowring,off due to voltage shutdown,will lower the voltage of the display electrodepull.followed by the previousgate drivertrace drop-down,sutraCsfeed throughelectricitypressure.the influence of this voltage is very heavy,because it is the main component of adjusting the voltage to the negative voltagepoints,must be able to adjust the overall voltage to the required finally itselfgate drivertrace voltage pullback,sutraCgdfeed throughVoltagering.Due to the comparison of the amplitude of the pull-back voltage,so the overall impact is also relatively.and8is the waveform change of positive electrode voltage,and negative polarity is onesample,it also has a three-stage voltage Benbodygate driverrouting is closedCgdfeed throughelectricitypressure,followed by the formergate drivewiring voltage pullbackCsfeed throughelectricitypressure,this voltage is the most important angle to push the display electrode voltage to the positive voltage rangecolor.and last is Benbodygate drivergenerated when the wire voltage pulls downfeed throughelectricitypressure,this voltage is due to the warpCgdoff,and the magnitude of the change is not,so the impact is also compared.




Since the operation of these voltagesmanagement,are all borrowedfeed throughVoltagering,we can use the meterfeed throughvoltage,according9voltage settingmeaning,to deduce the large voltage of each order.The results are as follows:

belong to the negative polarity voltagefeed throughelectricitypressure:

dV1=[Vg Ve(-)]*Cgd/[Cs Clc Cgd]

dV2= Ve( ) * Cs /[Cs Clc Cgd]

dV3= Ve(-) * Cgd /[Cs Clc Cgd]

belong to the positive voltagefeed throughelectricitypressure:

dV4=[Vg-Ve( )]*Cgd/[Cs Clc Cgd]

dV5= Ve(-) * Cs /[Cs Clc Cgd]

dV6= Ve( ) * Cgd/[Cs Clc Cgd]

in6,we mentioned the compensated positive and negative polarity output voltageandcommonvoltage should be one,is used to display the voltage range for the positive polarity.havefeed throughvoltage sum should be used for all negative polarity display voltage ranges.feed throughvoltage sum should be onesample.InstitutedV1 dV2-dV3should waiton-dV4 dV5-dV6.merger and simplification,we can get it:

Ve(-)-Ve( ) = 2Vg * Cgd / Cs

issaid,onlyVe (-)andVe ()differencevalue,meets the above requirements.,can achieve the effect of fourth-order drive.and the above formula also tells us a presentelephant,that is formulaic Jane,no longerClccomponent it follows the third-order drive onesample,will not sufferClcnonlinear shadowring.onVe (-)andVe ()determine?let's look backdV1 dV2-dV3and-dV4 dV5-dV6fruit:

dV1 dV2-dV3 = Vg*Cgd Ve( )*Cs =downfeed through

-dV4 dV5-dV6=-Vg*Cgd Ve(-)*Cs =Upfeed through

as long as we follow the characteristics of liquid crystalsex,you can know whether you need to go up or down.feed throughHow much does the total voltage needenough(is generally liquid crystalthresholdvoltage and maximum working voltagehalf),Refer to the panel design parameters again.Vg, Cgd, Cs,can calculate the requiredVe ()andVe (-).in mathematicssaid,when you put up and downfeed throughquantity,are all set upis0,can get itVe( )=-Ve(-)At this time, the fourth-order drive becomes the third-order drive..Therefore, the third-order drive can also be said to be a special feature of the fourth-order drive.Example.

Created on:2022年4月9日 22:36