《DVD激光头工艺》PPT课件.ppt

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1、DVDManufactureTechnologyDVD概略何謂DVD演進英文稱呼中文稱呼過去DigitalVideoDisc數字視頻光盤現在DigitalVersatileDiscs數字通用光盤過去現在下一代CD(compactdisc)RedlightDVDBluelightDVDCD/DVD/BluelightDVDComparisonDISCOpticalPickUp道間距最短訊息坑容量波長數字孔徑CD1.6mm0.8mm650MB780nm0.45DVD0.74mm0.4mm4.7GB635/

2、650nm0.6藍光DVD0.3mm0.168mm22G405nm0.85CD光盘坑纹DVD光盘坑纹蓝光DVD光盘坑纹DVDManufactureTechnologykeypointCorefunctionmoduleOpticalpickupMecha-deckServo&DecodeboardMaintechnologypointPartsmanufactureAndmeasurementModuleAssemblyandadjustmentModuletestSystemevaluationOp

3、ticalpickup外觀示例OB側面(PDIC所在)ObjectivelensACTcoverHolderlensSuspensionwireconnectorDampingholder側面(LD所在)PCBFPCOpticalpickup外觀示例OBandhalfmirror/fullmirror/collimator/LDHalfmirrorcollimatorFullmirrorOpticalbodyLaserdiodeGratingholderassy.opticalpickup基本原理(一

4、)光電系統動態示意opticalpickup基本原理(三)读出技术要點:聚焦到衍射极限的最小激光束.信息面的凹凸(pit/mirror)反射光的強弱不同.opticalpickup基本原理(四)主動式光電探測系統:信號源LD過程要點DISCObjectivelenscollimatorLaserdiodePDIC(photodiode)Half-mirrorgratingLDlensDisc/pitdecoderPDICOutputequip.lensSignalmodulationLightsign

5、alElectronicsignalaudio/videoDVD-ROMOPUschematic某公司DVD-ROMOPU完整的光路示意圖PDICＬＤ(laserdiode)（DVD：650nｍ）物镜(objectivelens)（DVD／CD共用）ＣＰ镜(couplinglens或collimator)（DVD／CD共用）光柵镜GratinglensCD：（780ｎｍ）全反射（Ｒ）镜reflectionmirror（DVD／CD共用）H棱镜(PBS或dichroicmirror)光柵grating（

6、DVD：650nｍ）検出（DT）镜detectionlens（DVD／CD共用）半透明半反射镜halfmirrorＬＤ(laserdiode)（CD:780nｍ）discACT的结构示例Lensholderassy.由物镜和AF线圈、TR线圈組成.通过经由S导线向线圈通电、以及和磁气回路的作用下依弗来明左手定律，朝AF(focus)方向和TR(tracking)方向动作。Lensholderassy.magnetActcoverDampingholderTR(tracking)AF(focus)Sus

7、pensionwireopticalpickup基本原理(二)LENSYOKEFocuscoilTRcoilMAGNETDISCverticaldeviationTrackingdirectionFocusdirectionFO/TRcoil和lens都固定在一個可活動的部件上﹐如果coil上通電流﹐受磁力作用﹐活動部就帶lens上下和左右運動(左圖示ACT,循跡時垂直紙面運動)。InneryokefocustrackMagneticdirectioncollimatorLightbeamACT工作原

8、理圖示TRcoilActuatorprofileObjectivelensyokeInneryokemagnetFocuscoilTrackingcoilLaserrayInneryokeTrackingcoilFocuscoilyokeLens/coilholdercollimatordiscmagnetopticalpickup基本原理(五)Actuator的作用:驅動lens作focusandtrackingTracking存在的主要原因:圖1(軌