本研究為可變焦透鏡運用在共焦測距系統上，進行透明物件的厚度量測。將待測物放置在測量範圍內，再 利用可變焦透鏡可以快速改變焦距的特性進行厚度的量測，因為待測物是透明的，所以探測光在穿透待測 物的過程中會經過兩次介質的轉換，而當光線聚焦在待測物的表面時會反射回相對大能量的反射線，光功 率計會偵測到反射光的峰值，在利用功率計以及 LabVIEW 程式，建立電流以及反射能量的關係圖，並從 數據中分析到兩個峰值後，找出當時的對應電流以及對應到的位置，即可透過這些資訊分析出物體的厚 度。

The work shows a confocal displacement sensor with a varifocal lens, which is driven through different current to change its focal length. The study shows the measuring results of the thickness of transparent object. With power meter measuring the power and LabVIEW program recording the power-current graph, which with two peak powers are presented and the current gap between two peaks could be transferred to two displacements to what the spacing is between is the thickness.