In-Cell觸摸屏原理2010.3.15Introductionoftouchpanel1.Resistivetouchpanel

1.1traditionalresistivetouchpanel(directlyglueonLCDmodule)

a.4/5/6/8-wireresistivetouchpanelb.digitalresistivetouchpanel(touchswitches,matrix)

1.2integrateresistivetouchpanelintoLCDcell(betweentopandbottomglasses)2.Capacitivetouchpanel

2.1capacitancechangedbydeformationoftopglass

2.2capacitancechangedbyinducedcurrentfromfinger2.2.1surfacecapacitivetouchpanel

2.2.2projectivecapacitivetouchpaneldetectselfcapacitancedetectmutualcapacitance3.Othertouchpanel(Infrared,SAW,Electromagnetic,Optical…)Resistivetouchpanel基本原理：觸摸時(shí)，兩層ITO互相接觸，從而在兩層ITO之間形成電阻通路根據(jù)上下基板材料，可分為filmonglass,glassonglass,filmonfilm等結(jié)構(gòu)。1.14-wireresistivetouchpanelLowlifetime(around1milliontimes)Lowtransmissivity(75%-85%)NotresistscratchLowestcostEasydetectcircuitWorkswithanystylus1.2Incellresistivetouchpanel—samsung(1)Basicprinciple: Whenpressed,thesensorswitchison(conductivecolumnspacercontactsensorelectrode) Fromplanview,attouchpoint,commonelectrodecontacttwosensinglinesperpendicularwitheachotherrespectively2.Capacitivetouchpanel

2.1capacitancechangedbydeformationoftopglass

2.2capacitancechangedbyinducedcurrentfromfinger2.2.1surfacecapacitivetouchpanel

2.2.2projectivecapacitivetouchpaneldetectselfcapacitancedetectmutualcapacitanceCellgapchangetype(1)Samsung’spatent(US20080048994)onlyposedabasicprinciple,itslayerstructureanddetaileddetectmethodisnotshowninthepatent.ThoughAUOhasmadeademo,thereareveryfewopenmaterialsofitsdetectprinciple.Theyusethesameprinciple:detectthecapacitancechangebetweencommonelectrodeandsenseelectrodebycellgapdeformation.Therearemanywaystodetectcapacitancechange,whichwaySamsungandAUOusedisunknown.AUOSamsungCellgapchangetype(2)AUO和LG的壓力式內(nèi)嵌觸摸屏樣品LCalignmentchangetype—Samsung(1)Samsung’spatent(US20050094038)firstproposedthismethod: BecausedifferentLCalignmenthasdifferentdielectricconstant,andwhenpressed,theLCalignmentischanged,sothattheLCcapacitancechanged.2.2.1SurfacecapacitivetouchpanelHave2conductivecoatings.Upperconductivecoatingistheworkingplane.Lowercoatingisshieldingplane.SurfacecapacitivetouchpanelSurfacecapacitivetouchpanelprinciple:Touchpointistreatedasconnectingtogroundbyacapacitor.Theresistorfromtouchpointto4cornersR1-4isrelatedtothedistancefromtouchpointto4corners.Themorethedistanceis,themoretheresistoris.Whenaddsinesignalon4corners,thecurrentat4cornersI1-4isinverseproportiontorelatedR1-4.BymeasuringI1-4,thetouchpointcanbedetected.SurfacecapacitivetouchpanelLonglifetime(around100milliontimes)Highertransmissivity(Canreach90%)OnlyworkwithfingersHighercostPatentissueComplexdetectcircuitFastresponsespeedSelfcapacitance自電容原理為當(dāng)手接觸時(shí)，等效為parasiticcapacitance增加，而且自電容檢測(cè)都是在前端（提供電源端）。檢測(cè)原理有很多，可檢測(cè)電壓、電流、電荷，下圖為chargetransfer檢測(cè)原理。通過開關(guān)依次開合不斷對(duì)parasiticcapacitance進(jìn)行充電放電，檢測(cè)放電時(shí)通過的電荷，當(dāng)有手指接觸時(shí)，流出電荷增加。DetectselfcapacitancePanellayout:generallyusing‘diamond’pattern,sothecapacitorfromfingertobothITOlayerswillbebigenough.Thedetectsequenceis,firstdetectselfcapacitanceatonelayer(red),onelinebyoneline,togetXposition,thendetectanotherlayer(blue),togetYposition.Sothisisfakemulti-touch.Projectivecapacitivetouchpanel自電容的多點(diǎn)觸摸定位問題：MutualcapacitancePanel圖案MutualcapacitanceDrivingmethod:Atdrivelayer(red),addpulsesignalonelinebyoneline,andotherlinesconnecttoground.Atsenselayer(blue),detectchargeonebyone.Whenallintersectionisdetected,themostchargedecreasedintersectionisthetouchpoint.Thismethodistruemulti-touch.Soappleclaimedthatiphoneisthefirst‘imagesensing’touchpanelintheworld.上表面和下表面diamond是錯(cuò)開的模型仿真結(jié)果NotouchTouchOthertouchtechnology紅外：透光度好，價(jià)格低，適應(yīng)惡劣環(huán)境缺點(diǎn)：分辨率較低，易損壞在屏幕四邊排布紅外發(fā)射管和紅外接收管，一一對(duì)應(yīng)形成橫豎交叉的紅外線矩陣。用戶在觸摸屏幕時(shí)，手指就會(huì)擋住經(jīng)過該位置的橫豎兩條紅外線，因而可以判斷出觸摸點(diǎn)在屏幕的位置。

Othertouchtechnology聲表面波：透光好，壽命長(zhǎng)缺點(diǎn)：易被油污，灰塵等影響，需經(jīng)常維護(hù)X軸發(fā)射器X軸接收器反射陣列可觸摸區(qū)域吸收殘波膠帶Y軸接收器Y軸