在本論文中，我們應用LED光源窄頻與可靠性高之優點，首先完成一多波長調變之光源，探討多波長光源於生物組織之傳播行為之差異。然後，我們建立一可靠有效的光學皮膚模型，使用蒙地卡羅光追跡之方式，模擬光於皮膚組織吸收與散射差異之特性，研究光於生物組織之能量傳遞行為，進而了解入射光在通過組織後，光被皮膚組織吸收和散射之現象，進而優化系統之效率。此研究方式透過電腦模擬，可有效了解光於生物組織可能之行為，提供更精確之光學系統設計，進而改良傳統反射式血氧飽合測定儀效率低之缺點。 本論文中，我們提出一新型式的反射式血氧飽合濃度系統，利用一菲涅爾透鏡來重新調制光入射待測生物組織的光學傳播行為，完成一高效能之反射式血氧濃度感測器。此新型血氧感測器可在在低訊號身體部位(如手腕)量測出血氧訊號，並且準確度達到醫療等級之水準。此項研究相信能對反射式血氧飽合濃度計之效率與準確性有所提升，使得非侵入式的生醫檢測有著更廣範之應用。 ;Photoplethysmography (PPG) is a useful technique that widely used to monitor blood changes which induced by cardiac pulsations. Pulse oximer uses this technique of PPG to estimate arterial blood oxygen saturation values (SpO2) and pulse rate (PR). In this thesis, a new reflective pulse oximeter is proposed and demonstrated with implanting a Fresnel lens, which enhances the reflected signal. An optical simulation model incorporated with human skin characteristics is presented to evaluate the capability of the new reflected optical system. Based on the skin model, the new prototype is optimized and realized. Compared with the other reflective oximeters, the reflected signal light detected by the photodiode is effectively enhanced. The prototype was able to accurately measure within an error of + 3% for SpO2 and PR respectively from the wrist.
