以3D列印製作用於太陽光通訊的可調變反射元件

Abstract

我們提出利用3D列印製作可調變反射元件的構想，並嘗試CCR回射器與拋物面鏡的設計或製作：元件在設計上為二維結構並首先以TracePro進行光追跡模擬以確認可行性，之後以FDM機台印製並交由廠商鍍覆鋁金屬做為反射面與元件之下電極，在製作PDLC層作為光強度調變機制後將元件摺起組裝以進行量測。 我們製作出的CCR元件各邊長為6.8公分，PDLC層約在壓幅45 V的1 kHz交流電下可達到On-state，並觀察到對比度5.97的明暗訊號。拋物面鏡則暫止於參數設計與初步組裝的模型，面鏡設計經徑向分析可以達到百分之百的收光效率，周向上的分割數、直徑大小及其所能達到的收光效率則在本文中定義了效率評估函數M來大致關聯，3D列印的面鏡僅在焦距20 cm下摺起時已十分接近平面鏡。 本研究之反射元件的主要創新點有三：第一，以3D列印製作元件，方便元件在研發階段的參數設計與測試，並允許微機械加工不易達成的大面積元件製作而因此適用大尺度的可見光通訊系統，此外3D列印的材料特性使成品更輕便可攜；第二，使用PDLC進行訊號調變，相對於斬光器等機械式調變構造輕薄且容易製作，並可直接透過電控進行調變；第三，以太陽光作通訊光源為目標，預計在室外提供無光源配置的被動元件通訊，並因為元件的反(回)射特性使移動物間的可見光通訊成為可能。

We proposed tunable reflecting components, corner-cube retroreflectors (CCR) and parabolic concave mirrors, which are developed by 3D-printing process. After the dimensions are determined, the designed structures are ray-traced in TracePro for preliminary surety of their feasibilities. The structures are initially printed flat, and after PVD-deposited aluminum coating and applied with a tunable PDLC layer, folded into the target devices. A 3D-printed CCR with each side of 6.8 cm are incorporated with a tunable PDLC layer; the contrast between the On- and Off-states can reach 5.97 at 45 V voltage amplitude. The development of parabolic concave mirrors is right on a stage of dimensional designing; analysis on radial and circumference aspects are conducted for an equation relates the dimensions to the light receiving efficiency. A 3D-printed prototype with the focal length of 20 cm is further constructed while its overall surface is nearly flat. Tunable reflecting devices proposed here have some benefits. First, 3D-printed structures are lightweight and the fabrication process is timesaving and low-cost. Second, PDLC-tuning layer is lighter and easier to form than those mechanisms based on mechanical tuning. The target of our devices is to be served in outdoor sunlight communication systems, potentially enabling motive visible light communication.