電容式隱形眼鏡眼瞼壓力感測器之設計、製作與量測

Abstract

本研究提出一個以微機電製程技術製作並可與隱形眼鏡整合之可撓性多通道電容式眼瞼壓力感測器。感測器結構是兩個三明治結構製成的平行板電容，上下極板間隔具有掏空結構用於填充介電質，使用隱形眼鏡材料HEMA (Hydroxyethyl methacrylate)作為電容感測器之介電值材料，感測器與隱形眼鏡整合後表面平順並無皺摺產生。元件皆以生物相容性良好的材料製作。主要感測原理為利用服貼角膜之隱形眼鏡嵌入多通道電容式眼瞼壓力感測器，當眼瞼覆蓋給予隱形眼鏡壓力時，將間接改變電容式眼瞼壓力感測器結構，導致感測器電容值產生變化，進而偵測眼瞼給予角膜的壓力分布。本論文利用自行設計的靜水壓力治具模擬眼瞼壓力，並對電容式隱形眼鏡壓力感測器進行測試。在動態量測部分，透過改變靜水壓力治具之水位高度給予電容式隱形眼鏡壓力感測器標準的壓力值，經實驗證明感測器能夠精準偵測 0.4mmHg 的壓力變化並且有相當好的重現性。

The purpose of this thesis is to provide the use of MEMS manufacturing technology to fabricate a flexible multi-channels capacitor eyelid pressure sensor which can be integrated with contact lens. This parallel plate capacitor consists of two structural sandwich plates, and both the upper and lower plates have a hollow structure for being filled with the dielectric. The contact lens material HEMA (Hydroxyethyl methacrylate) is used as a capacitive sensor dielectric material in this study. After integrating the sensor and contact lens, the surface will be smooth and have no wrinkles. All materials of the elements are biocompatible. The main principle of sensing is to observe the change in capacitance of the multi-channel capacitive eyelid pressure sensor embedded in the contact lens which covers the cornea very well. When the eyelid is covered by the contact lens, the eyelid will give pressure to the contact lens, and then it will indirectly change the capacitive eyelid pressure sensor structure, which causes the change in the sensor capacitance value. Then, the distribution of the pressure which eyelid gave to cornea can be detected. Finally, in the measurement section, a self-design hydrostatic pressure fixture was used to simulate the eyelid pressure and gave an accurate pressure value to our device. By changing the water level of it, the purpose of dynamic measurement is achieved, so that the capacitive contact lens pressure sensor can be tested. Experiments show that the sensor can accurately detect 0.4 mmHg pressure changes and have a good reproducibility.