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Published January 2019 | public
Book Section - Chapter

Wireless Implantable Intraocular Pressure Sensor with Parylene-Oil-Encapsulation and Forward-Angled RF Coil

Abstract

This paper presents a wireless and implantable intraocular pressure (IOP) sensor with parylene-oil-encapsulation packaging using a novel folded PCB architecture accomplishing practical RF coupling for power and data in a rabbit. The sensor is operated with an air gap of 5 mm between the primary coil and the animal, coupling to an on-chip coil at an input power of 32 dBm at 915 MHz, and can also be operated when the eyelid covers the sensor. Additionally, two novel results for parylene-on-oil deposition in general are presented. First, we show that the thickness of the porous layer of parylene-C (PA-C) and parylene-HT (PA-HT) deposited on silicone oils have a logarithmic decrease in porous layer thickness (PLT) versus silicone oil molecular weight (MW) over a range of 2–139 kDa. Second, we directly verify that parylene-oil-encapsulated pressure sensors retain sensitivity despite material buildup for the first time.

Additional Information

© 2019 IEEE. The authors thank Trevor Roper for maintaining the Caltech Micromachining Laboratory, Maya Ordoñez for help with parylene thickness measurements, and Shane Shahrestani for assistance during the rabbit experiment. We thank the Rosen Bioengineering Center, the Heritage Medical Research Institute, and the L. K. Whittier Foundation for financial support.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023