塗佈技術在傳統產業、微機電製程與半導體工業上運用十分廣泛，若能了解相關參數對塗佈的影響，選擇塗佈參數的過程便能簡易許多。本研究針對塗佈過程的細部做探討研究，此過程受到四種參數變化的影響，分別為基板移動速度、塗佈液流量、黏滯力與基板與流體接觸產生之表面張力。實驗採用直接觀察的方法，對流體自塗佈頭鋪展至基板之暫態塗佈過程，做塗佈的流體做寬度與接觸角變化的量測，以了解塗佈過程中，慣性力、流體黏滯力與和表面張力三者交互作用的影響，用以建構與了解塗佈過程之機制。 實驗觀測得知可將塗佈過程可分為五個時期：分別為液珠成長期、接觸擴展期、回縮期、擴展期與過展期。液珠的產生是由於塗佈頭橫截面吸附流體，液珠逐漸增大接觸基板形成液橋；流體接觸至基板向兩側擴展的現象受到流量與黏度的影響，尤以黏度影響較大；而回縮速度則受到黏度的影響，最後流量、黏度與表面張力的作用影響平衡的寬度。當流量過大或使用流體黏度較低時，容易產生過展期，反之則造成塗佈條紋斷裂，造成塗佈失敗。 Coating methods are widely used in the traditional, MEMS-related and semiconductor industry. In order to select the working parameters of the process correctly and simply, the study of the influences of related properties on the coating process becomes very important. This study is concentrated on the stripe coating transient process. The correlated properties of stripe coating are the velocity of moving plate, flow rate, viscosity and surface tension. For measuring the coating width and the contact angle between the fluid and moving plate, the CCD camera is used to record the images of the transient coating process. The interactions among inertia force, viscous force and surface tension is found to be the key factor from the experimental results. According to the experiment, five stages are proposed to describe the phenomena of spreading including drop growing, spreading of contact, recoiling, spreading, and over spreading. Drop growing is due to fluid being absorbed in the cross section of spreading head until it contacts with the base plate. Flow rate and viscosity would influence the spreading of contact, especially viscosity. When the fluid recoils, the recoiling speed is affected by viscosity. Finally the coating width is controlled by the flow rate, viscosity and the surface tension. Large flow rate and small viscosity will easily lead to over spreading, whereas small flow rate and large viscosity will easily lead to stripe breaking. Those mean coating fails.
