超大廣角鏡頭在溫度-20C至60C 對熱的分析與校正之鏡頭設計

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題名:	超大廣角鏡頭在溫度-20C至60C 對熱的分析與校正之鏡頭設計
作者:	高鳳遙;Kao,Feng-Yao
貢獻者:	光電科學與工程學系
關鍵詞:	廣角鏡頭;消熱差;熱膨脹係數;折射率的溫度係數;Wide angle lens;athermalization;Coefficient of linear thermal expansion;Temperature Coefficient of the Refractive Index
日期:	2016-08-03
上傳時間:	2016-10-13 13:17:35 (UTC+8)
出版者:	國立中央大學
摘要:	本文為四百萬畫素超大廣角鏡頭設計由七片玻璃組成，鏡頭焦距為2.212 mm，鏡頭長度22.66 mm，F/#為2.2，最大半視角為80，在環境溫度-20C至60C對熱的分析與校正。由於溫度變化不只會改變玻璃折射率，也會因鏡片與鏡片間熱脹冷縮，使鏡片曲率半徑、鏡片厚度、空氣間隙以及鏡面非球面係數及鏡筒也會有所改變。所以我們必須考量鏡片折射率的溫度係數(dn/dT)、鏡片膨脹係數(α)與鏡筒材質的膨脹係數(β)。隨著環境溫度的變化，鏡片參數值也會改變，在設計消熱差的光學系統中，其有效焦距也改變，即系統總屈光度會有所變化。在消熱差光學系統須使總屈光度與溫度之變化(d/dT)為零，如果d/dT無法消除則需使用鏡筒材質的膨脹係數(β)來補償，而達到消熱差設計，本文在消熱差設計過程中，是選用不同鏡筒材料的組合來達到消熱差的效果即利用此原理。在環境溫度-20C至60C間的超大廣角鏡頭之MTF(180 lp/mm)可達到0.451以上；相對照度達78.06 %以上；短波長(F-line)至長波長(C-line) 橫向色差最大值為1.482 m，短波長(F-line)至參考波長(d-line) 橫向色差最大值為0.848 m；F-theta畸變最大值在0.78 %；而超大廣角鏡頭設計加公差之MTF(180 lp/mm)最小值為0.210。 ;The study is about the design of ultra-wide lens, which has 4 Mega pixel, and compose of seven glass, the focal length of the lens is 2.212 mm, the total length is 22.66 mm, F/# is 2.2, the maximum of half field-of-view is 80 degree. The purpose of the study is to discuss about thermal analysis and correction of the ultra-wide lens when the ambient temperature range from -20C to 60C. The ambient temperature change not only making the refractive index of optical element change, but also making the radius, thickness of optical element, the space of air, the aspheric coefficient of surface and the mount are change. We must consider the temperature coefficient of the refractive index (dn/dT), the thermal expansion coefficient of the lens (α) and the thermal expansion coefficient of mount (β). With the ambient temperature change, the optical parameter values of optical element are change. In addition, the optical construction change affects the location of the focus. So we design athermal optical system, we make the change in optical power which due to a temperature change (d/dT) is zero. The d/dT relate to the temperature coefficient (dn/dT) and the thermal expansion coefficient of the lens (α). If d/dT cannot be eliminate, using the thermal expansion coefficient of mount (β) compensate to achieve athermal design. In this study, we choose different mount material to athermalized. In the ambient temperature range from -20C to 60C, the MTF (180 lp/mm) of the ultra-wide lens are larger than 0.451. The relative illumination can achieve 78.06 %. The maximum of lateral color from short wavelength (F-line) to long wavelength (C-line) is 1.482 m. The maximum of lateral color from short wavelength (F-line) to reference wavelength (d-line) is 0.848 m. The maximum of F-theta distortion is 0.78 %. And the minimum of MTF (180 lp/mm) of tolerance analysis is 0.210.
顯示於類別:	[光電科學研究所] 博碩士論文

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