镜头光学设计课件.ppt

1、鏡頭光學規格的介紹鏡頭光學規格的介紹Curtis主題主題Curtis內容大綱內容大綱1Pixel Size2Image Size3Image Circle 4Lens Composition5Field Of View(FOV)6F Number7Relative illumination(RI)8Chief Ray Angle(CRA)9Distortion10MTF11EFL12Back Focus Length(BFL)13Optical Total LengthLCM-*2Mega(Design)ItemLCM-*Sensor MI-XXXX，OV-XXXXPixel Size3.2

2、x 3.2mImage Size D:5.6 mm (H:4.48 V:3.36)Image Circle 5.9mmLens Composition1G3PField Of View59.5(at SENSOR Diagonal)F NumberF/2.8Relative illumination at 100%of Image Height55%(at SENSOR Diagonal)Chief Ray AngleD:19.7 H:20.6 V:20.5TV Distortion1%MTF CenterCenter 54%180 LP/mm 50%200 LP/mm at 70%of Im

3、age Heighth=70%T61%/S74%90LP/mm at 80%of Image Heighth=80%T59%/S69%90LP/mm at 90%of Image Heighth=90%T58%/S63%90LP/mm at 100%of Image Heighth=100%T59%/S72%90LP/mmFocus Lengthf=4.87mmBack Focus Length1.494mm Optical Total Length sensor size(D)。2、D+0.4mm(Package 公差)。MEMO：光學設計的考量，要從了解SENSOR開始。光學設計需與SEN

4、SOR達到最佳配合。PLWDP=Pixel sizesensor1CurtisRatioType NameAspect Ratio(W:H)Diameter(mm)Width(mm)Height(mm)Diagonal(mm)Diameter/Diagonal1/3.64:37.067.064.003.005.001.411/3.24:37.947.944.543.425.681.401/34:38.478.474.803.606.001.411/2.74:39.419.415.374.046.721.401./2.54:310.1610.165.764.297.181.411/24:312.

5、706.404.808.001.591/1.84:314.1114.117.205.359.001.572/34:316.9316.938.806.6011.001.5414:325.425.412.809.6016.001.594/34:333.8733.8717.4013.1021.781.561.83:245.7245.7223.7015.7028.401.6135mm film3:2n/a36.0024.0043.27n/aTypeSensorsensor2Curtis尺寸表FOV:Field Of ViewDfFOV=2 =2 tan-1 D/2f FOVsensor例：SENSOR

6、對角線D=5mm，焦點距離f=3mm，則FOV為：FOV=2 =2 tan-1 5/2*3 =79.6(度)CurtisF/#_1DfsensorF/#：決定光通量、影像的亮度。F/#=f/DI0 1/(F/#)2(進光量與進光量與F/#平方成反比平方成反比)。I0Image Intensity 流明流明 照度照度MEMO：F/#數值愈小 設計上困難度愈高。FOV愈大 設計上困難度愈高。CurtisF/#_2F/2.8比比F/4.0亮度亮兩倍。亮度亮兩倍。例：F/#=2.8&4，焦點距離f=50mm，則入光大小為：F/#=f/D；D=f/F/#1、D(F/2.8)=50/2.8=17.862、

7、D(F/4.0)=50/4.0=12.51、D(F/2.8)=50/2.8=17.862、D(F/4.0)=50/4.0=12.5以圓面積計算公式計算如下：(R2)1、3.14*17.862 10022、3.14*12.52 491(面積F/2.8)2*(面積F/4.0)CurtisF/#_3CCD靈敏度較靈敏度較CMOS為高。為高。不致能區不致能區線性區線性區飽和區飽和區exposureresponseMEMO：CCD所使用的F/#值較大(即光圈較小)。如果使用過大的光圈，則會落於飽和區 使得成像品質不好。CurtisMTF1黑黑白白Co (Bmax Bmin)/(Bmax+Bmin)=co

8、ntrast代表的是層次感、立體感。代表的是層次感、立體感。Lens design Good image QualityImage Quality：MTFDistortionCRA(tele-centric angle)RIFlare&GhostBmaxBminCurtis050100MTF0.51.0(lp/mm)MTF2截止頻率MTF Ci/CoCo：物：物Ci：像：像Optical systemNon-perfect lens因材料、加工、組立所產生的缺陷。100%70%CurtisMTF3S：Sagittal，弧矢面，放射狀。T：Tangential，子午面，同心圓狀。CurtisMT

9、F401001.0(lp/mm)截止頻率fNAliasing現象 False color Moire patternfN=Nyquist frequency =1/2p例：p=3.2m fN=1/(2*3.2*0.001)=1000/6.4 =156 (lp/mm)MEMO：如何消除Aliasing?利用“OLPF”。CurtisOLPF101.0(lp/mm)fN01.0鏡頭MTFOLPF_MTF1.0(lp/mm)01.0(lp/mm)fNfNOLPF：1、雙折射式(Crystal、quartz)2、繞射式(grating 光柵)CurtisOLPF2false colorsCurtisI

10、R_CUT Filter_114:33:24 IR_CUT FilterIR_CUT Filter1、反射式(Reflection type)：干涉鍍膜。2、吸收式(Absorption type)：藍玻璃。CurtisIR_CUT Filter_2規格標示例：650nm 15nm T=50CurtisIR_CUT Filter_3反射式反射式IR_CUT Filter的的Angle shift 問題問題入射角度增加，截止波長往短波長偏移。入射角度增加，截止波長往短波長偏移。吸收式吸收式_(藍玻璃、綠玻璃藍玻璃、綠玻璃)無無Angle shift 問題問題但，材料特性為質軟、容易起化學變化，但

11、，材料特性為質軟、容易起化學變化，容易吸水有潮解現象，耐候性不佳等問題。容易吸水有潮解現象，耐候性不佳等問題。CurtisCRA_1C.R.(30)CRA()Chief Ray Angle(CRA)A.SI0IImage plane與CRA有關的參數：1、cos4 Law：I=I0cos42、RI=I/I0 (相對照度)CurtisCRA_225Sensor端會要求CRA 符合此角度配合micro lens 的調整。(micro lens與sensor的距離，影響CRA需 求的大小)例：SENSOR的CRA要求希望25，A、RI=50 at 30()B、RI=55 at 30()誰優?實裝上，A周邊光亮比B亮，為何?因為，A的CRA()=25；B的CRA()=30A比B能配合SENSOR，故A比B亮。Curtis