This paper presents an ultra-thin and flexible polymer-based capacitive pressure sensor for intraocular pressure (IOP) monitoring in a mouse eye. Due to the size limitation of the anterior chamber in the mouse eye, a volume of approximately 700 × 700 × 150 μm(3) on a small substrate is available for the MEMS capacitive pressure sensor. Moreover, the sensor would ideally be easily injectable into place. Further complicating the sensing is the need to operate the device on the curved surface of the anterior chamber with minimum damage to the eye tissue. Therefore, a thin and flexible substrate is required. We fabricate sensors by exploiting Parylene as a biocompatible structural material in a suitable form factor and 25 μm thick liquid crystal polymer (LCP) as a soft and flexible host substrate. Using our approach, the flexibility and small form factor necessary for a mouse eye implant is achieved, along with the sensitivity required to monitor IOP fluctuations. This device will allow better study of glaucoma through close monitoring in mice after integration with other components.
This paper presents a novel, all-Parylene, thin, flexible 3-D packaging technology with an application demonstration of wireless powering. Parylene is utilized as a base substrate of a packaging interposer, and multilayer thin films are conformally stacked on the Parylene substrate. High-density (450 pF/mm 2 ) metal-insulator-metal capacitors are implemented with an ultrathin ( 47 nm) deposition of Parylene-N. The energy storage capabilities as well as RF characteristics are characterized. To demonstrate interposer applicability, an RF energy-harvesting study is performed by implementing a rectifier circuit on the Parylene interposer utilizing embedded capacitors of wide-ranging values and an antenna. Finally, substrate folding tests are performed to verify the applicability of the Parylene interposer in a flexible form factor without undergoing degradation in energy-harvesting capability. The thin-film flexible capacitors are demonstrated to not short-circuit even under the stress of folding the interposer.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.