可撓式駐極體能源轉換裝置之設計、製作與量測

Abstract

拜先進的超大型積體電路技術所賜，積體電路的能量需求已降至數十μW的程度，由環境獲取能量來驅動低功率的遠端感測器成為可能，又伴隨著醫療電子的進步以及個人化電子產品的流行，將人體運動作為轉換能量的來源，並提供電子產品的能源需求，可增加其產品的使用壽命以及降低耗能進而減少成本。相較於機械振動而言人體運動方式如手指、手肘以及關節彎曲等其行為較為複雜，故對應用於上述人體運動作為能量轉換來源的能源轉換裝置，其本身應具有可撓性。可撓性優點使轉換裝置不單單只受限於單一個部位(手指、鞋底等)或是單一種運動方式(單方向的振動等)，這使得能源轉換裝置應用範圍更廣，更適用於複雜行為方式的人體運動。另外倘若應用於人體的能量轉換裝置具有可撓性，便能減少其本身帶給使用者活動上的不便。 本論文之能量轉換裝置以Parylene C作為駐極體之材料，並以聚二甲基矽氧烷(PDMS)作為基板材料，以求達到可撓的需求。而本論文仍延續實驗室先前以駐極體的方式對轉換裝置充電，故將有以不同充電情況下對駐極體表面電位的衰減情況做量測以及分析呈現，而駐極體的表面電位從第一天的-352V衰減至-227V，為初始值的64%，其穩定性可達6個月以上(截至2013/4/17止)。 輸出功率量測部分，本論文考慮人體常見的下壓以及彎曲運動作為驅動方式，量測在固定下壓位移量為1mm且負載阻抗為1000 MΩ時，選用1、2、5、10以及20 Hz的下壓頻率模擬不同的行走速度，結果分別有8.4 nW、84.1 nW、0.184 μW以及2.19 μW的功率輸出。量測不同下壓位移量分別為0.4mm、0.6mm、0.8以及1mm，並固定負載阻抗為1000 MΩ及下壓頻率20 Hz時，其輸出功率分別為26 nW、0.132 μW、0.734 μW、1.31 μW、以及2.19 μW。 另外在轉換裝置的彎曲情況也在最大彎曲頻率為20 Hz時，，在不同彎曲程度下則分別有1.59 nW、3.54 nW、22.6 nW、57.8 nW以及82.4 nW的輸出功率。

Thanks for the low power CMOS VLSI technology, the power consumption is reduced to about a few tens of microwatts. Therefore, it becomes feasible to power portable devices by scavenging the ambient energy such as the human motion. Compared to mechanical vibration, the human motion of fingers, elbows and other joints is more complex, so the harvester needs to be flexible to use the body motion as an energy source. The advantage of flexibility is that the harvester can work for more than one human part (finger or foot) or one motion direction .This allows a wider range of applications of energy conversion and is more suitable for complex human movement. In order to achieve flexibility, we chose the Parylene C as the electret material and use the polydimethylsiloxane (PDMS) as the subtract material. We investigated the electret charge stability for various charging conditions. The surface potential is -352V at the beginning and decayed to -207V after six month, which was 59% of the initial value (until 2013/7/19) We consider the compression and bending which is common in human motion as the driving force in the output power measurement. The result was 8.4 nW, 84.1 nW, 0.184 μW and 2.19 μW when the pushing displacement was 1mm, load resister was 1000 MΩ, and push frequency was 1 Hz, 2 Hz,5Hz, 10Hz and 20 Hz respectively. The output power is 26 nW, 0.132 μW, 0.734 μW, 1.31 μW and 2.19 μW when pushing displacement was 0.4mm, 0.6mm, 0.8mm and1mm. In the bending case, one The output power was 1.59 nW, 3.54 nW, 22.6 nW, 57.8 nW and 82.4 nW respectively for different degree of bending.