本文主要以一廣域式離焦粒子影像測速法，於微混合器中進行粒子的三維軌跡追蹤。實驗中利用粒子於離焦時產生的影像變化，標定出粒子之離焦距離，並以數位攝影機拍攝粒子於流道中的流動情形，再針對影像中單一粒子的影像變化與位置變化，還原計算出粒子於流道中移動的軌跡。實驗利用SU-8負型光阻於矽晶片上製作出凸模，再以PDMS翻模製作出含有立體結構之流道，最後再以氧電漿處理將PDMS與載玻片接合以完成封裝。
目前實驗結果顯示，此方法能夠藉由簡單的架設獲得流道中粒子的三維移動資訊，並且成功的追蹤粒子於Z字型、對稱式脊型、非對稱式脊型等微型混合器中流動的軌跡，分析粒子於不同位置之瞬間速度，進而得到較詳細之混合器流場量化資訊。
未來的目標，將朝向利用此法，解析出更複雜的流道中粒子之移動現象與速度，進而了解不同的流道結構設計，可能對微流場造成的影響。

In this paper, three-dimensional movements of the particles inside the Stagger Herringbone Micro-mixer (SHM) were visualized by a wide-range defocusing particle tracking velocimetry (WDPTV). WDPTV is a simple method to obtain three dimensional information inside the micro-channels through a single camera setup. The principle of this method is based on the changes of the diffraction pattern at different defocusing distance. The radius changes of the defocusing particle images at different defocusing distances were recorded, and by correlating the images with the defocusing distances, the three dimensional location of the particles inside micro-fluidic device can be estimated. By adjusting the cover glass offset value on the objective, the spherical aberration effect will be inverted, thus ,the measurement range at the same defocusing distance could be increased to 200μm. This technique had been successfully applied to different micro-mixers including SHM, and the three dimensional flow fields were reconstructed to further study the mixing mechanism. This system can extract three dimensional information through simple setup and provide in situ information about the geometric effects of the micro mixers.

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