镜头光学设计课件

1、鏡頭光學規格的介紹Curtis主題1鏡頭光學規格的介紹Curtis主題1Curtis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 Length2Curtis內容大綱1Pixel Size2Image SiLCM-* 2Mega (Design) ItemLC

2、M-* Sensor MI-XXXX，OV-XXXXPixel Size3.2 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 Cente

3、rCenter 54% 180 LP/mm 50% 200 LP/mm at 70% of Image 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

4、)。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SENSOR達到最佳配合。PLWDP = Pixel sizesensor1Curtis51、Image circle sensor size(Dsensor2Curtis尺寸表6sensor2Curtis尺寸表6FOV:Field Of ViewDfFOV = 2 = 2 tan-1 D / 2f FOVsensor例：SENSOR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)Curtis7FOV

5、:DfFOV = 2 FOVsensor例：SEF/#_1DfsensorF/#：決定光通量、影像的亮度。F/# = f / DI0 1 / (F/#)2(進光量與F/#平方成反比)。I0Image Intensity 流明 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。Curtis8F/#_1DfsensorF/#：決定光通量、影像的亮度。IF/#_2F/2.8比F/4.0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、

6、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)Curtis9F/#_2F/2.8比F/4.0亮度亮兩倍。例：F/#=2F/#_3CCD靈敏度較CMOS為高。不致能區線性區飽和區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。Cu

7、rtis10F/#_3CCD靈敏度較CMOS為高。不致能區線性區飽和區MTF1黑白Co (Bmax Bmin) / (Bmax + Bmin) = contrast代表的是層次感、立體感。Lens design Good image QualityImage Quality：MTFDistortionCRA(tele-centric angle)RIFlare&GhostBmaxBminCurtis11MTF1黑白Co (Bmax Bmin) / (Bm050100MTF0.51.0(lp/mm)MTF2截止頻率MTF Ci / CoCo ：物Ci ：像Optical systemNon-pe

8、rfect lens因材料、加工、組立所產生的缺陷。100%70%Curtis12050100MTF0.51.0(lp/mm)MTF2截止頻率MTF3S：Sagittal，弧矢面，放射狀。T：Tangential，子午面，同心圓狀。Curtis13MTF3S：Sagittal，弧矢面，放射狀。Curtis1MTF401001.0(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 (l

9、p/mm)MEMO：如何消除Aliasing?利用“OLPF”。Curtis14MTF401001.0(lp/mm)截止頻率fNAliasOLPF101.0(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)Curtis15OLPF101.0(lp/mm)fN01.0鏡頭MTFOLPOLPF2false colorsCurtis16OLPF2false colorsCurtis16IR_CUT Filter_1IR_CUT FilterIR_CUT Filt

10、er1、反射式(Reflection type)：干涉鍍膜。2、吸收式(Absorption type)：藍玻璃。Curtis17IR_CUT Filter_1IR_CUT FilterIRIR_CUT Filter_2規格標示例：650nm 15nm T = 50Curtis18IR_CUT Filter_2規格標示例：650nm 1IR_CUT Filter_3反射式IR_CUT Filter的Angle shift 問題入射角度增加，截止波長往短波長偏移。吸收式_(藍玻璃、綠玻璃)無Angle shift 問題但，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。Curtis19IR_CUT Filter_3反射式IR_CUT FiltCRA_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)Curtis20CRA_1C.R.(30)CRA()Chief RayCRA_2Sensor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C