[[alternative]]Study on the Design and Manufacturing Processes of Diffractive Glass Concentrator

計畫編號：NSC101-2221-E032-013 研究期間：201208~201307 研究經費：687,000[[abstract]]隨著光電、半導體、精密機械等工業快速發展，在輕薄短小的同時亦對精度及性能 要求提升，因此高精度且具特殊形狀之工件需求量是與日俱增。在光學元件方面其 由平面 -> 球面 -> 非球面 -> 自由曲面(非軸對稱)之發展趨勢亦在提升性能表現 之要求下明晰易見。也就是說，在許多之應用中非球面/軸對稱之光學元件已不能滿 足學術/工業上之需求。繞射光學元件即是因應此一變革下的產物。近來在節能減碳 之大趨勢下其在太陽能集能模組等範疇上之需求亦大幅成長。在如此的背景下，發 展低成本、高精度的光學玻璃元件成型技術已成為市場上勝敗關鍵。玻璃模造技術 被視為最有機會製作出穩定性佳、具量產性且成本較低廉的玻璃透鏡。但以精密玻 璃模造技術生產玻璃繞射元件，不論國內國外，到目前為止都仍屬高難度、高失敗 率之製程。而聚光玻璃透鏡之製作可分為三大部分(1)精密模具之加工製作 (2)模具 保護膜(抗沾黏膜)之設計及鍍膜 (3)玻璃模造製程。目前玻璃模造業中最常使用之模 仁材料有碳化鎢(WC)、碳化矽(SiC)及非晶碳而其中又以碳化鎢為用量最大之模仁材 料。也因為其高硬度、高剛性，這些材料均為難切削材。當模造溫度在500oC 以內 時不鏽鋼也可成為適當之模具材料。因此本研究第一年將以車削/輪磨/拋光方式加 工繞射元件模仁並於模仁上鍍Pt-Ir基之抗沾黏膜而後成形玻繞射型璃聚光透鏡。除 探討模具材料、抗沾黏膜層與玻璃間在高溫時之介面化學反應及相關反應機制外， 也將建立3D模擬軟體對模造參數、玻璃物性、模具幾何形狀及成型過程應力/應變 及進行分析，此外加工參數如切深、進給、切速及刀具形狀等對加工表面之表面性 狀、表面/次表面微結構之影響，及鑽石刀具之磨耗特性進行研究。在計劃的第二年 將建立碳化鎢材料中不同鈷含量之被加工特性；開發阻能隔鈷與光學玻璃之相互擴 散的保護膜層設計。此外，也將嘗試以鑽石車削加工軟金屬(鋁合金、無氧銅)之繞 射光學元件壓印模(stamper)，而後以此壓印模對塗佈於超硬模具材料上之光阻進行 壓印，之後再對其進行電漿/RIE蝕刻以複製繞射光學元件之造型於超硬模具材料 上。[[abstract]]Owing to the fast development in opto-electronic, semiconductor, components of high precision and customized shapes are in great demand. The optical components have evolvedfrom planar, spherical, aspheric to free-form geometries. As a result, spherical/axial symmetrical optical components can no longer fulfill the need of academic research and industrial application. In comparison to conventional refractive lens, diffractive lens has the advantages of being thinner and lighter, and is widely used in optical systems such as lighting and photovoltaic systems. The big majority of the concentrators used for concentrated photovoltaic (CPV) energy today are made of plastics, for its superb formability, light weight and cheap price. However, plastics do have the setback of aging and degradation when subject to ultra-violet exposure. Glass, on the other hand, being heavier and more expensive than plastics, can sustain the UV light without any trouble. To get around these problems, diffractive lens and glass molding process (GMP) are selected in this study to reduce the weight and cut the cost. Simulations together with molding experiments will be conducted to analyze the stress/strain conditions and the obtained dimensional accuracy under various molding parameters. This project aims to study the fabrication processes of mold inserts for molding precision glass diffractive optical elements (DOEs). Since the stainless steel can be put to use if the molding temperature can be further lowered to below 500oC, it is included in this study to prepare for the low Tg glasses. The stainless steel will be plasma nitrided and subsequently diamond turned to generate aspheric lens arrays and diffractive optical elements (DOEs) for molding low Tg glasses. The surface integrity and wheel wear are to be examined using FESEM, Raman, XRD, AES, AFM.. and the results will be correlated to the machining parameter used. Efforts will also be made to use the SPDTed soft metal as a stamp to imprint the diffractive patterns onto the photoresist that coated on the hard mold material. The patterned mold will subsequently be RIEed to generate the DOE patterns. Low Tg glass gobs with will be used as the performs in this study.[[sponsorship]]行政院國家科學委員