本研究以控制相對照度為主軸，設計車用超廣角鏡頭，提出投影立體角之相對照度控制方法並討論如何使用F-θ畸變檢視超廣角鏡頭影像變形量。最後利用幾何方法，降低間距變化量的敏感度以及降低元件偏心的敏感度，使這兩項公差影響程度減緩，成功地提高了整個鏡組的良率。 本研究自定義之投影立體角相對於光學軟體計算值於此設計最大誤差約有8 %，但是變化特性曲線是相似的。若再搭配軟體計算的穿透率，相對照度的誤差可以降低至0.94 % 左右。F-θ畸變檢視是依據像平面處的影像間距變化情形進行評價，並避開F-θ畸變的缺點，最後訂定了小視角區域與大視角區域的各別目標值。處理公差時利用的幾何方法為讓曲面變平滑與增加間距，使間距變化量與元件的的偏心量相對於設計尺寸變小，如此即能降低這兩項的公差影響程度。最後，成功設計出全視角150度、相對照度為75.2 % 之超廣角鏡頭設計。The purpose of this study is to control the relative illumination on the image and design an ultra-wide angle lens that installed around a car. The concept of projected solid angle, that control the relative illumination on the image area and discuss how to use the F-θ distortion to estimate the deformation of image, is proposed in this study. We use its geometric relationship to reduce the sensitivity of thickness variation and element decenter, which can successfully increase the yield rate of the ultra wide angle lens.Calculating the projected solid angle by user defined function with the software is different from that by the default method. The maximum error rate between them is about 8 %, but the characteristic curves are similar. If we considered the transmittance factor, the maximum error rate between them will be reduced to 0.94 %. Besides, we estimate the variation of the real image height to avoid the defect of F-θ distortion, and set the targets for the maximum field of view. Furthermore, let the aspheric surface smoother and increase the thickness between any aspheric surfaces, which can reduce the tolerance sensitivity of the thickness variation and the element decenter. Finally, an ultra-wide angle lens with the properties of 150 degree field of view and more than 75.2 % relative illumination is successfully designed in this study.
