A Thin-Film Piezoelectric Microactuator Optically Powered via an Integrated Micro-Solar Cell

Abstract

A novel optically powered microactuator is developed via the integration of a thin film piezoelectric microactuator with a micro-solar cell on the same chip. The integrated microactuator has an overall area of 2×2 mm2 and is less than 0.25 mm in thickness. The paper presents the details of fabrication and preliminary experimental results confirming the optical actuation. The solar cell is fabricated by doping a n-type dopant in a p-type silicon wafer. The thin film piezoelectric microactuator is fabricated alongside the solar cell via the solgel method. The microactuator prototypes are tested for optical actuation under low light intensities in the range 0.1-1.26 W/m2, and corresponding center point displacements of the actuators and the photovoltages output by the solar cells are measured. An unpoled microactuator prototype produced a maximum displacement of 31 nm corresponding to an input light intensity 1.26 W/m2.

Differential stimulation of the retina with subretinally injected exogenous neurotransmitter: A biomimetic alternative to electrical stimulation

“…Furthermore, the maximum temporal stimulation rate of 3.5 Hz demonstrated at 22 °C with pulsatile glutamate injections is comparable to what has been deemed adequate for enabling rudimentary reading and daily functions in patients using electrical prostheses in clinical trials14. The use of a perforated MEA necessitated using room temperature conditions (see Methods) but higher temporal stimulation rates are likely achievable at physiological temperatures, especially with finer on-chip actuation of glutamate in a custom microfluidics device383940. Temperatures closer to physiological could also result in higher spatial specificities than those reported here since the glutamate uptake rate, which affects the diffusion distance of glutamate and therefore the spatial resolution, has been reported414243 to be faster compared to room temperature.…”

Chemical stimulation of rat retinal neurons: feasibility of an epiretinal neurotransmitter-based prosthesis

“…Ultimately, we envision a flexible, multiport device that will interface with the retina as shown in figure 1. Each port of this device will contain an optically powered microactuator for dispensing glutamate when given an appropriate light stimulus [23][24][25]. These microactuators will interface with small internal reservoirs of glutamate connected to a needlelike injection port (tip diameter ∼10 μm).…”