本論文主要在研究應用於焦電型紅外線移動物體感測器的多焦點式複合型菲涅爾透鏡之光學設計技術。首先，根據幾何光學追跡理論，推導感測器內部的光學系統之追跡關係式，並從中建立演算程式以進行分析。根據上述方法擬合出適當的複合型菲涅爾透鏡的幾何參數，並使用光學追跡設計軟體驗證其有效性；接著，進一步分析此感測器內部的光學系統，如對移動人體的感應靈敏度和有效感測的空間範圍；最後，使用上述工具，進行光學系統功效之提昇設計，提昇的重點主要有三項：增加近距離感測區間1~3公尺、感測角度增至半角50°、安裝高度增至2.8 公尺，如此以提高感測靈敏度。;The main objective of this project is to develop technology of compound Fresnel lens for pyroelectric infrared sensor (PIR sensor). This project is based on the theory of geometric optical tracing and derives mathematical relations. The two-dimensional contour of the compound Fresnel lens can be quickly design by establishing a calculation program. We use optical tracking software to verify the validity and accuracy of the self-built program. The compound Fresnel lens is a compound of sub-Fresnel lenses with different focal lengths. Here each sub-Fresnel lens works on a moving object at a specific distance to increase the sensing range and sensitivity of pyroelectric infrared sensor. After optical design and improvement by our research. The pyroelectric infrared sensing system which can reached the fallowing relevant specifications such as : The Fresnel lens calculation program can change the focal length as required, The aperture size and lens center position can be designed according to different requirements, Sensing half-angle : 50°, Detection distance : 1~12m, Sensor installation height : 2m and 2.8m. In this study, the optical tracing calculation program of the compound Fresnel lens was used to successfully design the geometric parameters. And use optical design software to analyze the sensitivity and effective sensing range of this system to moving human body.
