In-Cell觸摸屏原理2010.3.151整理pptIntroductionoftouchpanel1.Resistivetouchpanel

1.1traditionalresistivetouchpanel(directlyglueonLCDmodule)

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

1.2integrateresistivetouchpanelintoLCDcell(betweentopandbottomglasses)2.Capacitivetouchpanel

2.1capacitancechangedbydeformationoftopglass

2.2capacitancechangedbyinducedcurrentfromfinger2.2.1surfacecapacitivetouchpanel

2.2.2projectivecapacitivetouchpanel2.2.2.1detectselfcapacitance2.2.2.2detectmutualcapacitance3.Othertouchpanel(Infrared,SAW,Electromagnetic,Optical…)2整理pptResistivetouchpanel基本原理：觸摸時，兩層ITO互相接觸，從而在兩層ITO之間形成電阻通路根據上下基板材料，可分為filmonglass,glassonglass,filmonfilm等結構。3整理ppt1.14-wireresistivetouchpanel在兩電極上加5V直流電在ITO均勻電阻平面上形成均勻穩恒電流場在另一面的ITO電極上測量電壓根據測得電壓值（0-5V）確定觸摸點的位置用同樣方法測量Y坐標4整理ppt1.14-wireresistivetouchpanelLowlifetime(around1milliontimes)Lowtransmissivity(75%-85%)NotresistscratchLowestcostEasydetectcircuitWorkswithanystylus5整理ppt1.2Incellresistivetouchpanel—samsung(1)Basicprinciple: Whenpressed,thesensorswitchison(conductivecolumnspacercontactsensorelectrode) Fromplanview,attouchpoint,commonelectrodecontacttwosensinglinesperpendicularwitheachotherrespectively6整理ppt2.Capacitivetouchpanel

2.1capacitancechangedbydeformationoftopglass

2.2capacitancechangedbyinducedcurrentfromfinger2.2.1surfacecapacitivetouchpanel

2.2.2projectivecapacitivetouchpanel2.2.2.1detectselfcapacitance2.2.2.2detectmutualcapacitance7整理ppt2.1Capacitivetouchpanel(壓力式)Thisintegratetypehassomedifferentstructures,includes:Cellgapchangetype Samsungfiledapatent(US20080048994).AUOhasmadeademo.LCalignmentchangetype Samsungfiledpatent(US20050094038)veryearly,butSamsung’sdemoappliedanotherdetectcircuit(SID0724.3),andEpsonmadeademo(SID0855.2)basedonSamsung’sstructurebyusingLTPS,IPSandactivematrixsensorsothatimprovedtheperformance.8整理pptCellgapchangetype(1)Samsung’spatent(US20080048994)onlyposedabasicprinciple,itslayerstructureanddetaileddetectmethodisnotshowninthepatent.ThoughAUOhasmadeademo,thereareveryfewopenmaterialsofitsdetectprinciple.Theyusethesameprinciple:detectthecapacitancechangebetweencommonelectrodeandsenseelectrodebycellgapdeformation.Therearemanywaystodetectcapacitancechange,whichwaySamsungandAUOusedisunknown.AUOSamsung9整理pptCellgapchangetype(2)AUO和LG的壓力式內嵌觸摸屏樣品10整理pptLCalignmentchangetype—Samsung(1)Samsung’spatent(US20050094038)firstproposedthismethod: BecausedifferentLCalignmenthasdifferentdielectricconstant,andwhenpressed,theLCalignmentischanged,sothattheLCcapacitancechanged.11整理pptLCalignmentchangetype—Samsung(2)Samsung和Epson的in-cellLCalignmentchangetypeTPSamsungEpson12整理ppt2.2.1SurfacecapacitivetouchpanelHave2conductivecoatings.Upperconductivecoatingistheworkingplane.Lowercoatingisshieldingplane.13整理pptSurfacecapacitivetouchpanelSurfacecapacitivetouchpanelprinciple:Touchpointistreatedasconnectingtogroundbyacapacitor.Theresistorfromtouchpointto4cornersR1-4isrelatedtothedistancefromtouchpointto4corners.Themorethedistanceis,themoretheresistoris.Whenaddsinesignalon4corners,thecurrentat4cornersI1-4isinverseproportiontorelatedR1-4.BymeasuringI1-4,thetouchpointcanbedetected.14整理pptSurfacecapacitivetouchpanelLonglifetime(around100milliontimes)Highertransmissivity(Canreach90%)OnlyworkwithfingersHighercostPatentissueComplexdetectcircuitFastresponsespeed15整理ppt2.2.2投射電容觸摸屏(PCT)投射電容觸摸屏（projectivecapacitivetouchpanel）可分為兩種不同的結構：自電容(selfcapacitive)與互電容(mutualcapacitive)自電容為較早的技術，來源于touchkey,touchpad互電容技術由iphone發揚光大，發展迅猛，將逐漸取代自電容類型16整理pptSelfcapacitance自電容原理為當手接觸時，等效為parasiticcapacitance增加，而且自電容檢測都是在前端（提供電源端）。檢測原理有很多，可檢測電壓、電流、電荷，下圖為chargetransfer檢測原理。通過開關依次開合不斷對parasiticcapacitance進行充電放電，檢測放電時通過的電荷，當有手指接觸時，流出電荷增加。17整理pptDetectselfcapacitancePanellayout:generallyusing‘diamond’pattern,sothecapacitorfromfingertobothITOlayerswillbebigenough.Thedetectsequenceis,firstdetectselfcapacitanceatonelayer(red),onelinebyoneline,togetXposition,thendetectanotherlayer(blue),togetYposition.Sothisisfakemulti-touch.18整理pptProjectivecapacitivetouchpanel自電容的多點觸摸定位問題：19整理pptMutualcapacitance互電容原理為：當手指接觸時，等效為互電容改變，互電容檢測一般是在后端（sense端）。可以檢測電壓或者電荷。下圖為電荷檢測等效電路。手指接觸后等效為互電容減小，此時讀出電荷減小。模型一20整理pptMutualcapacitancePanel圖案21整理pptMutualcapacitanceDrivingmethod:Atdrivelayer(red),addpulsesignalonelinebyoneline,andotherlinesconnecttoground.Atsenselayer(blue),detectchargeonebyone.Whenallintersectionisdetected,themostchargedecreasedintersectionisthetouchpoint.Thismethodistruemulti-touch.Soappleclaimedthatiphoneisthefirst‘imagesensing’touchpanelintheworld.上表面和下表面diamond是錯開的22整理ppt模型仿真結果NotouchTouch23整理ppt互電容的優點互電容相對自電容的顯著優點：對地寄生電容對觸控檢測影響很小，更適合在集成觸摸屏結構具有更強的抵抗LCD噪聲能力可以實現真正的多點觸摸（不會有鬼點）但互電容是一個更加新的技術，目前幾乎