Development of Rolling Hot Embossing of Double-sided Microstructure on Glass for Optical Application

玻璃材料光學性質佳，機械強度高且抗蝕性強，能製作高品質之光學元件。尤其將微米與奈米結構製作於玻璃光學元件表面，能減少反射或導光。在玻璃上製作微結構，常使用電子束微影或雷射加工等，昂貴且耗時；而微熱壓複製成型技術如微熱壓成型又有製程時間長，且為批次生產。為達到連續生產、快速量產、降低成本，本研究利用熱滾壓方式成型，先預熱玻璃，當溫度達至玻璃轉移溫度左右時，將基材與熱盤移至熱滾輪進行滾壓，並搭配下模具，達成雙面微結構複製。 本研究先利用光學模擬軟體Trace Pro找出增強光強度之雙面微結構組合，包括V-cut及微透鏡；結果顯示雙面平行V-cut之增光強度效果最好。接著，本研究設計組裝滾壓機台，鎳質滾輪模具與平板鎳質模具，分別置於玻璃基材上下方，升溫滾壓製作之雙面平行V-cut玻璃，測其光強度比無結構之玻璃高。本研究並以田口實驗設計L9表，探討雙面結構熱滾壓成型之接觸溫度(熱盤、滾輪)、非接觸溫度(紅外線)、滾輪壓力、移動速度之重要因子與最佳組合。結果顯示最重要因子為滾輪壓力與移動速度。以最佳參數所製造之雙面平行V-cut玻璃，其光強度較無結構玻璃多約20μW/cm2。 本研究又進一步製作適用於高溫熱壓玻璃之玻璃碳模具，以澆鑄方法製作呋喃模具，在惰性氣體環境下，高溫炭化成玻璃碳模具。實際應用於熱滾輪壓印之下模，利用玻璃碳模具之抗沾黏特性，使結構高度成果更佳且更為均勻。 本研究並將所製作之雙面平行V-cut玻璃應用於染料敏化太陽能電池之入光面，由於光強度提高，電池電流密度較無結構玻璃提高26 %，電池效率提高34 %。Glass is the preferred material for quality optical devices due to its high refractive index and low color aberration. Glass also possesses high mechanical strength and chemical resistance. Surface with microstructures and sub-wavelength nanostructures futher enable light guiding or antireflection capabilities. Currently, most micro or nano structures on glass are manufactured by e-beam lithography or laser machining techniques which are expensive and time-consuming. Mold replicating process such as micro/nano hot embossing has disadvantages of discontinuous process and long cycle time. In this research, for continuous and fast production, hot rolling method for glass substrate was developed. The glass was pre-heated to glass transition temperature (Tg) before it was embossed by roller and plane molds for dual-side microstructures. This research consists of three major parts. First, Trace Pro software was used to find out lumininous intensity of glass with different combination of v-cuts and micro-lens in surfaces. The result showed that the best module was glass with double parallel v-cut structures. This research also design an implement heating and hot rolling facility. Roller and plane Ni-molds with v-cut structures were used to emboss heated glass. The measured lumininous intensities from glass with microstructure were higher than that from bare glass. Then, Taguchi method L9 was used to investigate the significance of processing factors including speed, pressure, infrared temperature, and temperature of roller and hot plate. The results showed that speed and pressure were more important than others. Moreover, glass with dual-side v-cut microstructures was the best combination of processing parameters fabricated by rolling embossing. The lumininous intensity of the glass was 20μW/cm2 higher than that from bare glass. In the second parts, a simple and novel method to fabricate high-temperature resistant glassy-like carbon (GC) mold with microstrutures was proposed and studied. Furan precusor was produced by casting, then GC mold was obtained after carbonization process in the inert environment. Because of the anti-adhesive property of GC, the microstructures produced by the GC mold in rolling embossing was better and more uniform than that from Ni mold. In the last part, the glass with parallel v-cut microstructures on both sides was used as the top surface of dye-sensitized solar cell. The current density and efficiency of solar cell were 26% and 34.2%, higher than that from similar solar cell but with bare glass as the top surface.目錄 誌謝 i 摘要 ii Abstract iii 目錄 v 圖目錄 x 表目錄 xvi 第1章 導論 1 1.1 前言 1 1.2 光學玻璃之介紹與應用 1 1.3 玻璃微結構精密成型技術 6 1.4 微熱壓成型技術介紹 8 1.5 滾輪壓印成型 10 1.6 玻璃碳材料之應用 12 1.7 研究動機與目標 13 1.8 論文架構 14 第2章 文獻回顧 15 2.1 玻璃微熱壓成型技術 15 2.2 使用於玻璃基材加工之微奈米模具製作 20 2.3 微結構滾壓成型技術 26 2.4 雙面微結構成型相關技術 30 2.5 玻璃碳材料之應用 34 第3章 實驗設備 38 3.1 實驗目的與整體流程規劃 38 3.2 本實驗使用之玻璃種類 38 3.3 玻璃滾輪壓印機台設備 40 3.3.1 玻璃滾壓機台架構 40 3.3.2 加熱元件 41 3.3.3 滾輪、加壓裝置與移動平台 42 3.3.4 陶瓷墊片 42 3.4 呋喃模具製程設備 43 3.4.1 快速真空泵浦 43 3.4.2 橫臥式石英管高溫真空爐 43 3.5 染料敏化太陽電池 44 3.5.1 二氧化鈦(TiO2) 44 3.5.2 碘化鉀(KI) 45 3.5.3 D719染料 45 3.5.4 ITO-PEN可繞式基板 46 3.5.5 太陽能模擬器 46 3.6 量測設備 47 3.6.1 光譜儀 47 3.6.2 光強度計 47 3.6.3 表面輪廓儀 48 3.6.4 雷射共焦顯微鏡 48 3.6.5 光學顯微鏡 49 3.6.6 熱電耦溫度計 50 第4章 滾壓雙面微米結構製程於光學玻璃 51 4.1 滾輪壓印測試接觸長度與連續滾壓之壓力均勻度 51 4.1.1 富士感壓軟片作用原理與步驟 51 4.1.2 滾輪連續滾動壓力均勻度 52 4.2 雙面結構模擬分析 56 4.2.1 TracePro 原理與介紹 56 4.2.2 結構模擬設定 57 4.2.3 結構模擬結果與討論 59 4.3 田口法原理與使用 65 4.3.1 田口法介紹 65 4.3.2 K-PG325光學玻璃操作窗 67 4.4 田口分析雙面結構參數之探討 70 4.4.1 頂面高度結果分析 71 4.4.2 底面高度結構分析 75 4.5 結果與討論 78 4.5.1 實驗之最佳參數 78 4.5.2 光學玻璃上之成形結果探討 78 4.5.3 光強度與結構之關係 81 第5章 耐高溫模具應用於雙面結構滾輪壓印製程 82 5.1 玻璃碳模具製作 82 5.1.1 波璃碳模具製程 82 5.1.2 PDMS模具製程 84 5.1.3 呋喃模具製程與成型視窗 85 5.2 玻璃碳模應用於滾壓玻璃結果 92 5.3 玻璃碳模具應用於熱滾壓玻璃結果與討論 97 第6章 染料敏化太陽能電池之應用 98 6.1 染料敏化太陽能電池之介紹 98 6.2 染料敏化太陽能電池(DSSC)之原理 99 6.3 染料敏化太陽能電池組製程 100 6.3.1 有機染料製備 100 6.3.2 TiO2電極製備 100 6.3.3 電解液製備 101 6.3.4 相對電極製備 101 6.3.5 染料敏化太陽能電池組裝 102 6.4 結果與討論 104 第7章 總結與未來研究方向 107 7.1 研究成果總結 107 7.1.1 滾壓雙面微米結構於光學玻璃 107 7.1.2 製作耐高溫模具於雙面滾壓微結構製程 107 7.1.3 染料敏化太陽能電池之應用 108 7.2 未來研究方向 108 REFERENCE 11