以3D列印之高分子分散型液晶元件架設太陽光通訊系統

Abstract

本實驗室提出利用3D列印製作可調變之反射元件並架設以太陽光為光源的可見光通訊系統。本論文的主題在於架設通訊系統，當中更優化先前實驗室所製作之元件，為了達到較好的通訊品質為目的。首先，元件優化部分：利用卡榫取代摺紙結構，藉由縮小單一面積改善列印大面積所造成之翹曲問題。而反射面則是利用鏡面取代鍍鋁的方式來增加反射率，最後，利用毛細現象的方法製作PDLC層作為光強度的調變機制後進行量測。我們在光學桌上利用白光(鹵素燈)與凸透鏡模擬太陽光量測優化後元件的對比度，其PDLC層大約在150 V達飽和且對比度為1.124相較於優化前(1.025)好。此外，ITO所造成之反射光仍是一大問題，不過仍可以適用亮暗調變 (OOK) 之應用。 系統架設部分我們利用Matlab將字串轉為ASCII的二進位形式並以NRZ編碼設計訊號且連接至訊號產生器，另一方面我們搭載了1 kHz的弦波使PDLC能有效率的操作。接收端則以工業相機設置低解析度(高幀數)錄製，最後利用Matlab進行影像分析與解調。期間我們還利用望遠鏡將系統實際架設在太陽光下進行測試，並且評估中遠距通訊的傳輸品質，在我們定義的誤碼率下推測最遠距離大約為45公尺。 本研究所製作反射元件的創新特色為：利用3D列印製作元件，可以客製化尺寸大小且容易調整，其規格可配合市售之鏡子列印框架，重量輕巧方便攜帶；再者，其使用PDLC進行調變，可透過電壓直接進行調變，相對於機械式調變如斬光器輕薄且易製作；最後，以再生能源的太陽光為通訊目標，在室外提供無光源配置的被動元件，加上元件的回射特性可實現動態的可見光通訊。

Visible light communication (VLC) has an indispensable role to play in communications industry. We harbor the belief that it can bring us a tremendous change due to the license-free, high security and immunity to electromagnetic interference. In the thesis, we present a 3D-printed 6.7*7.5 cm-scale tunable reflecting components, corner cube retro-reflector (CCR), and draw a comparison between previous device and optimized one. The new CCR is assembled from a structure of a joggle joint instead of origami structure; simultaneously, we replace Al by mirror as a reflector layer. As for PDLC, it is analogous to the previous one; ultimately, contrast ratio between the On-state and Off-state can reach 1.124 at 150 V. By applying voltage to drive the PDLC on the CCR and using Non-Return-To-Zero encoding (NRZ) to build waveform can achieve signal transmission. The intensity of the light at the RX is used to return the 0 and 1 of the original signals; finally, our system’s maximum transmission distance can be inferred to 45 m. We harbor the idea that by using 3D printing and sunlight to build communication system can reap huge benefits: renewable energy, high security, lightweight device, low cost, and a timesaving process. The target of our communication is to be served in outdoor and provide high data rate, potentially enabling motive visible light communication. The features can ameliorate the whole work efficiency and environmental protection, so we pour attention to do the research in it. We have published several papers, and hope to rich notions in this area.