DE LIN INSTITUTE OF TECHNOLOGY Lens Stops Aberration

DE LIN INSTITUTE OF TECHNOLOGY 內容大綱 Ø光的傳播 Ø透鏡（Lens） Ø光欄（Stops） Ø像差（Aberration） © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw 2

DE LIN INSTITUTE OF TECHNOLOGY 光的傳播（三）5 Ø折射定律（Snell’s Law） ni sinθi= nt sinθt © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

DE LIN INSTITUTE OF TECHNOLOGY 光的路徑具有可逆性 8 © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

16 DE LIN INSTITUTE OF TECHNOLOGY 例題：凹凸透鏡兩邊曲率半徑為 10 cm、15 cm，折射率為 1. 5，求其置於空氣中的焦距。 f = 60 cm © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

DE LIN INSTITUTE OF TECHNOLOGY 當兩薄透鏡接觸在一起 焦距f 2 Fo Fi Optical axis Fo = Fi = F F ： 有效聚焦長度 © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw 19

DE LIN INSTITUTE OF TECHNOLOGY Stops(孔徑光欄) 20 n限制進入系統的光能量 n. Stops可以限制鏡面範圍，使通過的光線成為近軸光 線，以減少像差用來減少像差 © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

DE LIN INSTITUTE OF TECHNOLOGY Aperture stop & Field stop Aperture stop：限制進光量 Field stop：限制視野 © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw 21

DE LIN INSTITUTE OF TECHNOLOGY F-number (F-數值) n. F數值是光通過鏡頭量大小的表示。 n. F數值愈小表示通過的光量多 n F-number=( f / D ) D : 入瞳的直徑 f : 焦距長 n. Large F-number Dim(微暗的; 模糊的 )image n Large depth of field/focus (focus is forgiving) n n. Small f-number Bright image n Small depth of field/focus (focus is critical) n © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw 22

23 DE LIN INSTITUTE OF TECHNOLOGY © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

24 DE LIN INSTITUTE OF TECHNOLOGY © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

DE LIN INSTITUTE OF TECHNOLOGY 薄透鏡特性 26 © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

像差分類 27 DE LIN INSTITUTE OF TECHNOLOGY n像差 (Aberration) 球面 Spherical n 慧差 Coma n 像散 Astigmatism n 場曲 Curvature n 畸變 Distortion n n色像差 (Chromatic Aberration) © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

Spherical Aberration 28 DE LIN INSTITUTE OF TECHNOLOGY “off-axis” ray “paraxial” ray l l 焦點隨離軸高度而改變 fobj 成像點形成對稱式光斑 球面鏡的本性(故稱為球差) 多鏡片組合或非球面可減少球差 © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

29 DE LIN INSTITUTE OF TECHNOLOGY © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

DE LIN INSTITUTE OF TECHNOLOGY Barrel distortion (桶形畸變) Distortion 30 Pincushion distortion （針插畸變） © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw

DE LIN INSTITUTE OF TECHNOLOGY Astigmatism © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw 31

32 DE LIN INSTITUTE OF TECHNOLOGY 謝謝大家耐心觀看 簡 報 結 束 敬 請 指 教 © 2005 DLIT, All rights reserved http: //www. dlit. edu. tw