電容式隱形眼鏡眼壓感測器之設計、製作與量測

Abstract

本論文研究為提出一個利用微機電製造技術製作具可撓式並且可以嵌入隱形眼鏡內之電容式眼壓感測器，利用透明的聚對二甲苯(parylene C)作為基材與絕緣層，金作為電容之上下極版電極，其結構是兩個三明治結構製成上極板與下極板，上下極板中間介質為隱形眼鏡材料HEMA (Hydroxyethyl methacrylate)的環狀結構，接著隱形眼鏡模具做結合，結合後表面平順並無皺摺產生。製程皆使用生物相容性良好的材料。電容感測器的優點為靈敏度高、動態響應快與較不容易受到環境影響，其訊號處理範圍為低頻訊號不受高頻影響，並且降低後端處理電路設計的難度與電路消耗功率。主要的感測原理根據眼壓自然變化造成眼角膜形變，並利用貼服於角膜之隱形眼鏡內嵌入電容眼壓感測器做為感測角膜輪廓變化的方式而間接得到眼壓的變化。在動態量測部分，將感測器放置在自行設計與真實角膜曲率與大小相仿的仿生眼球上做感測器的動態測試，結果顯示當仿生眼球腔體灌入50 uL水量時，仿生眼球曲率產生非常微小變化，感測器能夠正確偵測並且有相當好的重現性與反應速度，靈敏度大約為0.5 pF/mmHg。

The main sensing principle based on intraocular pressure(IOP) caused by natural variations in corneal deformation, using capacitive IOP contact lenses sensor paste clothes in cornea and sensing changes in the manner in which the corneal contour changes in intraocular pressure indirectly. This paper reports a study of the use of MEMS manufacturing technology to fabricate a flexible IOP sensor that can be embedded in a contact lens, using a transparent parylene C as a substrate and an insulating layer, gold as the upper and lower electrode of the capacitor electrode. It is a cyclic structure consists of two structural sandwich plates which is filled by HEMA and between top plate and bottom plate. Then the sensor will combined with contact lens molds. After combining contact lens surface smooth and no wrinkles. Biocompatible materials had been used. This sensor shows a high sensitivity, fast dynamic response, and less susceptible to environmental effects. Also it won’t be affected by high frequency signal, and can reduce the difficulty of the design of circuit. In the dynamic measurement section, the sensor is placed on self-designed and size similar bionic eye for sensor dynamic testing. Results show that when the bionic eye cavity was poured into 50 uL of water, bionic eye curvature produce very small changes, the sensor can correctly detect and have a fairly good reproducibility and response speed. Sensor sensitivity is about 0.5 pF / mmHg.