- 學位論文
環形曲面紫外光固化氣囊輔助壓印複製微結構製程研發
Development of Gasbag-Assisted UV-Based Imprinting Process For Replication of Microstructures onto Cylindrical Surface
摘要
傳統壓印製程技術使用壓板機構對基材進行加壓，容易導致壓力施加不均勻，若平面壓板在曲面上壓印微結構壓印，壓板與曲面僅有部分接觸，無法完全貼合，部份局部應力過大，複製不均勻，壓印面積大受限制。本論文針對在環形曲面上複製微結構的需求，提出氣囊輔助壓印複製微結構製程，透過氣囊撐開外圍具有微結構的PDMS軟模，利用氣體的物理性質達到均勻的壓力分佈，且氣囊的可撓曲性將可完整貼附環形基材，有效提升微結構的成型均勻性。 本研究首先將管狀氣囊組件、氣囊加壓組件、驅動組件和曝光組件等四個單元結合，成功組立一部曲面氣輔紫外光壓印機台。管狀氣囊的製作方式是以切削方式製作鋁合金啞鈴狀滾輪，外層包覆一撓性佳並具有高延展性的矽膠材料，形成一個密閉腔體； PDMS軟模的製作方式主要利用具微結構的電鑄鎳模，結合微鑄造成型將V-cut微結構製作在PDMS軟模表面。 經富士感壓軟片測試證實，氣囊輔助能夠有效地增加模具與環形基材間的壓力均勻性。在適當的實驗參數下，可成功將微結構複製於環形基材內壁，且平均微結構高度複製率約為93%。 藉由探討環形曲面微結構的光學性質，發現V-cut微結構有效的增加環形基材表面光強度和光均勻性，可應用於曲面導光板製作，更進一步利用此光學性質，將其應用於膠囊內視鏡的照明系統改善上，增加其光線散佈面積，達到更好的照明效果，並製作曲面奈米結構抗反射層降低內視鏡成像亮點。本研究也比較V-cut微結構和微透鏡陣列應用於光學增亮片的光學效果。
並列摘要
For conventional imprinting process, the substrate and the stamp are brought into contact directly by the plate and rigid mold, it is difficult to fabricate microstructures on cylindrical surface. In this study, a gasbag-assisted UV imprinting process and flexible PDMS mold are employed to replicate microstructures onto cylindrical surface, making use of physical properties of gas to enhance close contacting and uniformity of pressure during cylindrical surface imprinting. A gas-assisted UV-based imprinting facility was designed and imprinted. The facility contains gasbag, air pressure system, motor driving system and exposure system, designed and is assembled. The gasbag, which is composed of aluminum shaft and silicon tube, is employed to sustain the PDMS flexible mold with microstructure and compress the substrate. With aid of Fuji prescale film test, the results of gasbag-assisted imprinting process has shown not only uniform pressure but also close contact between the stamp and the cylindrical substrate. Under suitable conditions, the V-cut microstructures can be replicated on the curved substrate completely. The height of replicated structures is over 93% compared to the master mold. According to the result of optical test, the light intensity and brightness in the cylindrical PMMA has been enhanced significantly with V-cut structure. It shows great potential application in fabricating curved light guide plate. The result of this research is also used in illumination system of capsule endoscope for enlarging illuminated area. The anti-reflective characteristic of PMMA with nano-pillar array has also been verified.