射出成形光學透鏡的靜態光散射特性

Static Light Scattering Characteristic of Injection Molded Optical Lenses

王傳均(Chuan-Chun Wang)

指導教授 ： 陳仁浩

國立交通大學/工學院/機械工程系所/碩士(2019年)

摘要

智慧型手機的光學鏡頭的品質除了由材料本身的折射率與透光度等物理性質所影響外，其非結晶性材料內部可能會形成尺度數奈米至數十奈米之短距離結構，這些短距離結構會造成高分子內部的局部密度與折射率分布不均，並導致光學鏡頭的成像品質降低。
本研究目的為建立一套靜態光散射系統，並探討成形光學透鏡之靜態光散射特性。研究中使用PMMA作為對象材料，藉射出成形製作平凸光學透鏡，搭配與PMMA同折射率之液體，再利用紅、紫兩可見雷射光源以偏振光照射透鏡之各處觀測點，調查光學透鏡之散射特性。
研究結果顯示高分子光學透鏡內部存在局部密度分佈不均，在空氣中靜態光散射強度與局部密度呈現中至高相關性，而液體中散射由於殘留刀痕影響呈現低相關性。散射系統中放入液體能降低表面粗糙度之影響，但無法將其完全消除。紫光雷射較紅光雷射適合用於散射實驗。
本研究建立一套靜態光散射系統，利用兩可見雷射光源調查高分子光學鏡頭之散射特性，並討論散射光之離散程度以及與密度之相關性，可作為未來近一步靜態光散射檢驗方法之參考。

關鍵字

靜態光散射 ； 非結晶性材料

並列摘要

Optical lenses quality in smart phones is depending on the refractive index and transparency of the used material. Amorphous polymer materials may contain short-range structures with size between several and tens of nanometers. Short-range structures cause inhomogeneous refractive indices and local density in optical lenses, leading to undesirable imaging.
This work aims to build a static light scattering system, and investigate the scattering characteristic of injection molded optical lenses. Polymethyl methacrylate (PMMA) plano-convex lenses are formed via injection molding. Two visible polarized light sources(red and purple laser) are then injected into measuring points to observe scattering behavior of these optical lenses. Refractive index matching fluid is added as appropriate.
Experimental results show that polymer optical lenses exhibit local density fluctuation. A moderate to strong positive relationship between static light scattering strength and local density is observed when the experiment is performed in air. A weak relationship is observed when performing the experiment with refractive index matching fluid, because of remaining machinery mark on the container. Refractive index matching fluid can decrease the influence of surface roughness within static light scattering system, but does not eliminate it. Purple light is more suitable than red light for static light scattering method.
This work constructs a static light scattering system and uses two kinds of visible laser to investigate the scattering characteristic of injection molded optical lenses. Furthermore, this investigation discusses the relationship between static light scattering strength and local density. This work can be applied as a reference of further studies of static light scattering examination.

並列關鍵字

Static Light Scattering ； Amorphous

參考文獻

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[2] Goldstein, M., and Michalik, E. R., 1955, "Theory of Scattering by an Inhomogeneous Solid Possessing Fluctuations in Density and Anisotropy," Journal of Applied Physics, 26(12), pp. 1450-1457.

[3] Stein, R. S., and Rhodes, M. B., 1960, "Photographic Light Scattering by Polyethylene Films," Journal of Applied Physics, 31(11), pp. 1873-1884.

[4] Stein, R. S., and Wilson, P. R., 1962, "Scattering of Light by Polymer Films Possessing Correlated Orientation Fluctuations," Journal of Applied Physics, 33(6), pp. 1914-1922.

[5] Rhoades, A. M., Williams, J. L., Wonderling, N., Androsch, R., and Guo, J., 2017, "Skin/core crystallinity of injection-molded poly (butylene terephthalate) as revealed by microfocus X-ray diffraction and fast scanning chip calorimetry," Journal of Thermal Analysis and Calorimetry, 127(1), pp. 939-946.