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1Lesson3TFT-LCD-Introduction林義成彰化師範大學／顯示所2內容{TFT-LCDintroduction{TFT-LCDdesignconcepts{Wideviewingangletechnology{ODFprocesstechnology{LTPStechnology3TFT-LCDintroduction4TFTLCD相關應用分佈圖5TFTLCDgenerationanalysis6TFT-LCDInfrastructureinTaiwanSource;交通大學謝漢萍7TFT-LCDSystemSource;中興大學劉漢文8TFT-LCDStructure&OperatingMechanism(1)9WhatisaTFTLCD?zHowtoreadthespecificationofaTFTLCDpanel?z=monitor&func=info&product_id=3&items_id=1101.Sizez有效顯示區域(ActiveArea)的對角尺寸zCRT一般的尺寸係指映管的對角尺寸，但在組合成顯示器時，通常會再遮去部份大小，如：17”CRT之可視區域約為16.0吋Source;中興大學劉漢文112.Resolution(pixel)122.Resolution(pixel)133.ActiveArea(mm)有效顯示區域z[(337.9mm)2+(270.3mm)2]0.5/25.4(inch/mm)=17.0inchzLCDPanel的有效顯示區域，即可顯示文字圖形的總面積，參考下圖，白色區域即此片Panel的有效顯示區域。IntheviewingareaoftheLCDglass,thedimensionsoftheperimeteroftheconductivearea.143.(AspectRatio)畫面比率zAspectRatio為畫面寬與高之比率。電腦畫面及一般影像畫面比率為4:3HDTV則可提供16:9的寬平面螢幕畫面。Therelationshipofwidthandheight.Whenanimageisdisplayedondifferentscreens,theaspectratiomustbekeptthesametoavoid'stretching'ineithertheverticalorhorizontaldirection.Formostcurrentmonitors,thisratiois4:3.ForHDTV,theratiowillbe16:9or16:10.154.Pixel(Dot)Pitch164.(Sub-pixel)175.Mode:TwistedNematic(TN)zAtypeofliquidcrystalwherethealignmentsurface,andthereforetheliquidcrystalmolecules,isoriented90degreesfromeachsurfaceofglass.zTherearesomanyLCmodes,suchasSTN,IPS,VA,…186.NumberofColorszGraylevelszNumberofColors=[GraylevelsofR]x[GraylevelsofG]x[GraylevelsofB]z4-bitx324x24x24=4096z5-bit+6-bit+5-bit(total16-bit)25x26x25=65,536(64K)z6-bitx326x26x26=262,144z8-bitx328x28x28=16,777,216(16.7M)197.ColorSaturation(%)zChromaticitydiagram,CIEx,y(CommissionInternationaledel'Eclairage)zNTSCratio(percentageoftrianglearea)208.ViewAngle(U/D/L/R)〈視角〉z面對螢幕，往其上、下、左、右四方觀測，調整此螢幕直到其無法由此四方看到螢幕畫面之角度。以監看者之視覺舒適，可調整視角之廣狹。AconeperpendiculartotheLCDinwhichminimumcontrastcanbeseen.218.ViewAngle(U/D/L/R)〈視角〉zViewingangledependsonitsstatementabout“ContrastRatio”{Iso-ContrastContour22TNLCD之灰階反轉問題ViewingangledependenceofTNSource:奇美韋忠光239.Brightness(nit)zLuminance〈明亮度〉z明亮度指一物件之可見亮度。其取決於可反射光之多寡並由一平方公尺(cd/m2)內之多少燭光來衡量其亮度。因表面物之反射屬性之多樣化，類似的照明度因物件表面反射屬性之不同而造成不同的明視度。例如，同樣的光源照射於一黑一白的房間，黑色房間之明視度相較於白色房間的明視度是非常低而且昏暗。2410.ContrastRatiozThedifferenceinluminancebetweenall-whitedividedbythebrightnessofanallblackzAtnormaldirection2511.ResponseTime(ms)〈應答時間〉z螢幕畫素接收到信號後，由白轉黑(Tr)及由黑轉白(Tf)所需轉變時間。所需轉變時間是越短越好。較短的反應時間使畫面轉換更為順暢。一般而言，其都低於60ms.Responsetime=Tr+Tf。Timeintervalbetween10%(on)to90%(on)or90%(off)to10%(off)ofbrightness.2612.InterfacezLVDS(LowVoltageDifferentialSignaling)NationalSemiconductor/TI(FlatLink)z數位顯示介面，具有高效能、高速與低功率消耗等特色。2712.InterfacezOtherinterfacesinclude:{RSDS(ReducedSwingDifferentialSignaling)→NationalSemiconductor{TMDS(TransitionMinimizedDifferentialSignaling)→SiliconImage(PanelLink){GVIP(GigabitVideoInterface)→Sony{DVI(DigitalVisualInterface)→DigitalDisplayWorkingGroup(DDWG),expectedtobecometheindustrystandard.2812.InterfaceSource;中興大學汪芳興2913.Backlightz液晶Panel的背面所設置光源。螢光燈管（熱陰極管或冷陰極管）、導光板、擴散板所構成。zTypesofbacklightsources3013.BacklightzCCFL(冷陰極射線管)(ColdCathodeFluorescentLamp)z將高壓施加於燈管之兩電極,電子即由電極端射出,電子因受高電壓加速而與管內之水銀原子撞擊,水銀原子在被撞擊後由不穩定狀態急速返回穩定狀態時,會將過剩能量以紫外線(253.7nm)釋放出來,此釋放出來之紫外線由螢光粉吸收轉換成可視光。3113.BacklightzLED:以兩種半導體相結合成的自發光原件，以電流驅動，具有高輝度特性。32LCDBacklightSource;://://(移動假影)35TFT-LCDdesignconcepts36DrivingofLCDPanel37一個電晶體(OnePixel)動作示意圖Source;中興大學劉漢文38a-Si:HTFT原理39EquivalentCircuitofUnitPixel40TFTLCDOperationConceptszElectricalpotentialDWaterlevelzTFTDWaterfaucetzInterconnectionsDWaterpipeszCapacitorsDWatertanksSource;中興大學劉漢文41TFTLCDOperationConceptzCharging{Filleachtanktoitsownwaterlevelz1tankatatimez1rowoftanksatatime{RefreshfasterthaneyescansensezFramerate~60Hz42TFTLCDOperationConceptzHolding{Keeptheleveluntilnextrefresh{LeakagezIncreasetanksizezStoragecapacitor43TFTLCDOperationConceptzSignalcoupling{unwantedlinksamongpipesandtankszSignaldelay{distancefromsourcezDrivingload{volumeofpipes*Bytheway,canyouimageahydrodynamicsystemwithoutanyfaucet?←PassivematrixLCD44UnitPixel&EquivalentCircuit45EquivalentCircuitofaPanel46TFTTimingchart47HowtoDriveaTFT-LCDPanel?LiquidcrystalrequiresACdriving!!48AM-LCDDrivingSource:ERSO吳永富49TFTLCDDesignConceptszOpticalaspect{AperturezElectricalaspect{TFToffcurrentzlowenoughtoholdvoltageacrossLC{TFToncurrentzlargeenoughtochargeLC{Parasiticcapacitancezlowenoughtooverridesignalcouplinganddecreaseloading{Parasiticresistancezlowenoughtosignaldelay50TFTDesignzDesignGuideline{Chargingtothecorrectlevelduringswitchon。{Holdingthelevelcorrectlyuntilnextframe。51TFTLCDDesignConceptszCharging:Q=IxT=CxV{I=K(W/L)(Vgs–Vth)Vds{K:flowspeed{W:faucetdiameter{L:faucetlength{Vgs-Vth:valveopendegree{Vds:waterleveldifferencezT:availabletime{pixelatatime:1/60/row#/column#{rowatatime:1/60/row#zC:tanksizezV:leveltarget52TFTLCDDesignConceptszHolding:Q=ixt=CxV{i:proportionaltoW{t:timetonextrefreshzalmost1/60zC:tanksizezV:acceptabl