高分子微結構介電材料之電容式觸覺感測器

Abstract

本研究提出一個具可撓式電容觸覺感測陣列以感測不同大小與方向之正向力與剪應力，可應用於機器人電子皮膚上提供觸覺訊號回饋。電容感測單元包含互鎖式微結構的聚二甲基矽氧烷(PDMS)介電層、金屬陣列電極和聚一氯對二甲苯薄膜作為軟性基板(Parylene-C)。經過翻模、轉印製程可以將尼龍濾膜上的微孔隙構造轉移至PDMS表面形成密集微圓頂構造。在微小壓力區間內，互鎖式介電層結構中的微圓頂構造因受壓產生大量形變，逐漸將內部空氣間隙填滿造成感測器介電常數上升。此介電層結構能有效提升壓力感測的靈敏度並大幅縮短反應時間。相較其他利用微加工技術製作出的模具，本研究利用翻模、轉印製作出的微結構具有製程簡便，低成本等優勢。量測結果顯示與平面式介電層結構相比，互鎖式微結構之介電層構造設計將感測器靈敏度提升15倍。同時，直徑10μm的微圓頂結構之靈敏度高達0.715kPa-1。

In this work, we present a flexible capacitive sensor array as the electronic skin (e-skin) for robot tactile applications. The capacitive sensing array is capable of measuring both normal and shear forces. The sensing element consists of interlocked polydimethylsiloxane (PDMS) dielectric layers and gold electrode arrays. The PDMS dielectric layers were patterned with microdome structures by using nylon membrane filters, which enhance the sensitivity of the tactile sensor significantly. This proposed process is a relatively simple and effective way to pattern microstructures compared to the other approach using micromachined molds. Further, the sensitivity of the capacitive tactile sensor can be adjusted using the nylon membranes with different pore sizes. Capacitance vs. pressure measurements indicate that the sensitivity of device with the interlocked microdome dielectric layer is about 15 times greater than the device with a planar dielectric layer. Also, the capacitive sensing element with 10 μm microdome size exhibits the highest pressure sensitivity of 0.715 kPa-1.