由於高功率LED發光效率提高，使得LED可嘗試使用於手術燈上。相較傳統之鎢鹵素燈體積大且效率低，尤其是會將許多電能用在紅外線波段，需加以處理否則將造成病人病情惡化及醫生不適，LED則無以上之缺點。而在手術進行的過程中，會出現多種不同的照明需求，因此手術燈必須具備調整照明焦距以及範圍的功能。本研究設計一具改變照明焦距能力之LED手術燈，利用旋轉變焦透鏡來改變焦距。透鏡設計使用Tailored Freeform Method產生輪廓，此為離散之設計方式，可達到精準控制光線行進方向。並依照Edge Ray Principle設計數種目標點分佈模式，讓透鏡在旋轉過程中有不同導光方向，由此產生變焦效果，並探討其設計品質。此後，使用變焦透鏡與LED模組進行整體手術燈配光分析，最終之設計結果滿足規格中之變焦要求及IEC-60601-2-41規範中手術燈之最大照度、平坦度、照傷深度等要求。

Due to the high energy transfer efficiency, LED (Light Emitting Diode) is now considered to be a good light source of the surgical operating lamp. The usage of halogen light source in traditional surgical operating lamp has several disadvantages such as big spot size and low efficiency, and most importantly, the high intensity of the infrared ray which would cause the illness of both Doctors and patients.
It is found that during the process of surgery, illuminations for different wound depth and light field area are required, therefore, the adjustable lighting focus or spot size of surgical operating lamp could offer better operating qualities without relocate the operating lamp. In this research we design a LED surgical operating lamp which be able to change focus by rotating the lens of the surgical light. We analyze the ray paths and generate corresponding lens profile using Tailored freeform method. After analysis, we design the lens arrangement according to projection point requirement by using the edge ray principle, which could redirect the direction of the light rays when rotating the lens. This ray redirection can change the focus point of the light. Then, together with LED model, we simulate and analyze the overall lightening distribution. The final design meets both the objective of focus-changing and specifications of surgical operating lamp in IEC-60601-2-41.

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