隨著科技的蓬勃發展，光電產品不斷的推陳出新，從感光底片到數位相機時代，人們對於影像品質的追求越來越高，尤其朝向微小化尺寸的發展。小尺寸的光學透鏡用途廣泛，在醫療上能作為膠囊式內視鏡減少病患對於侵入性治療的不適感；在軍事上能進行不易使敵人察覺的超小型偵查機使用；而在生活上能發展出高畫質的視訊鏡頭或手機鏡頭。因此在光學元件的發展上，對於微小尺寸且複雜結構之光學透鏡有很大的前景。相較於塑膠透鏡，玻璃透鏡有更優越的化學性質，例如耐侵蝕、不易受潮、黃化等優點；在物理性質上，玻璃比塑膠更加耐刮、抗磨損、光學透性佳。所以高品質的微小透鏡是個很有前景的發展方向。 本研究致力於開發一套完整之次毫米玻璃微透鏡之研製成果。在本研究中進行了光固化樹脂鑽石砂輪之開發，以不同粒徑(2~4μm與30~40μm)的小尺寸砂輪(φ0.5mm)進行粗加工與精加工，應用於次毫米微玻璃透鏡之碳化鎢模具加工上，並成功生產出形狀精度達到0.12μm且表面粗糙度(Ra) 可達到2nm之模具。由於小尺寸砂輪(φ0.5mm)在模具加工上會因為砂輪的磨耗使得加工精度不佳，因此要透過多次的補償與加工方能達到對形狀精度的品質要求。將加工完成之碳化鎢模具對微小玻璃球(φ0.5mm)進行模造熱壓，其成果相當貼近模擬結果，探究其原因是由於玻璃球僅0.5mm，因此腔室內上下均熱板溫度能迅速且平均的傳遞至玻璃球上，使得模造溫度達理想狀態。成形透鏡之形狀精度能達到0.4μm以下且表面粗糙度達到10nm(Ra)以下。從各項研究結果證實，本研究所進行的樹脂砂輪開發與碳化鎢模具之製造能成功研製出次毫米玻璃微透鏡。 As the market driven demand in optical and electro-optical industries heading towards smaller, lighter, and higher quality, more and more optical components with micrometer to sub-millimeter feature size are required to be machined to very good surface finish and high profile accuracy. Typical examples include: endoscope/capsule endoscope, surveillance camera, mini optical monitoring systems, smart phones and wearable devices. In comparison to plastic lenses, glass lenses have higher and more stable refraction index, higher transmissivity, better chemical/mechanical resistance and better environmental durability. This means that whenever high resolution and high quality images are required, glass lenses will be the better choice. This research aims to develop a feasible and effective process to fabricate sub-millimeter glass lenses. To carry out the precision micro-grinding of tungsten carbide (WC) mold for glass molding, resin bond diamond grinding wheels of various grit sizes are produced by mixing, coating and UV-curing. Those wheels are trued to 0.5 mm or less in diameter and used in precision slant grinding process. WC molds are successfully generated to a surface finish and profile accuracy better than 2 nm (Ra) and 0.12 μm (P-V) respectively. Glass lenses are molded by these WC molds to a surface finish and profile accuracy better than 10 nm (Ra) and 0.4 μm (P-V) respectively in this study. This shows that the fabrication processes developed in this study are feasible and can be used to produce sub-millimeter glass aspheric lenses effectively.
