非侵入式无线无源MEMS眼压传感器

Non-invasive Wireless and Passive MEMS Intraocular Pressure Sensor

连续监测眼压对于辅助诊断与治疗青光眼疾病具有重要作用,现有的眼压传感器存在相对灵敏度较低、中心谐振频率较高、制作工艺难度大等问题。为了解决上述问题,该文提出一种基于MEMS的非侵入式无线无源型眼压传感器。该传感器为5层堆叠结构,采用Parylene作为柔性衬底层、铜作为电极层、PDMS作为介电层,其中电极层和介电层构成两个电感和两个电容,形成C-L-C-L串联谐振电路。通过MEMS平面工艺和热塑形方法制作成能够与眼球紧密贴合的曲面形状,这种设计方案能有效地解决传感器的制作工艺难度大等问题。实验结果表明:该眼压传感器的中心谐振频率降低到了40 MHz,相对灵敏度达到1028.57 ppm/kPa,能够分辨出最小50 Pa(0.375 mmHg)的眼压值变化,为实现长期、连续性地监测眼压提供了技术支持。

Continuous monitoring of IntraOcular Pressure （IOP） plays an important role in the diagnosis and treatment of the glaucoma. Existing IOP sensors have some problems, such as low sensitivities, high central resonant frequencies and difficult fabrication. In order to solve the aforementioned problems, this paper presents a wireless, passive and non-invasive lOP sensor based on MEMS technology. The sensor contains five stacked layers, where Parylene, copper and PDMS are adopted as the functional materials within two flexible substrate layers, two electrode layers, and a dielectric layer, respectively. The electrode layers and the dielectric layer consist of two inductors and two capacitors to form a resonant circuit in C-L-C-L series. In the term of fabrication, a MEMS planar process followed by thermally shaping is proposed to fit curved surfaces of the eyeballs, and then this design scheme can effectively solve such issues as the difficulty in making the sensor and so on. Experimental results show that the central resonant frequency is decreased to 40 MHz, relative sensitivity is quantified as 1028.57 ppm/kPa, and resolution reached up to 50 Pa （0.375 mmHg）. This study can be used for long-term, continuous monitoring of IOP.