Laser driven miniature diamond implant for wireless retinal prostheses

TL;DR

This paper presents a fully wireless, miniaturized retinal implant powered by laser and integrated with diamond packaging, enabling high-density electrode control for potential use in retinal prostheses.

Contribution

It introduces a laser-powered, diamond-packaged miniature retinal implant with integrated ASIC and high-density electrodes, advancing wireless retinal prosthesis technology.

Findings

Achieved 55% photovoltaic power conversion efficiency.

Demonstrated wireless control of 256 electrodes.

Enabled high-density integration in a compact implant package.

Abstract

The design and benchtop operation of a wireless miniature epiretinal stimulator implant is reported. The implant is optically powered and controlled using safe illumination at near-infrared wavelengths. An application-specific integrated circuit (ASIC) hosting a digital control unit is used to control the implant's electrodes. The ASIC is powered using an advanced photovoltaic (PV) cell and programmed using a single photodiode. Diamond packaging technology is utilized to achieve high-density integration of the implant optoelectronic circuitry, as well as individual connections between a stimulator chip and 256 electrodes, within a 4.6 mm x 3.7 mm x 0.9 mm implant package. An ultrahigh efficiency PV cell with a monochromatic power conversion efficiency of 55% is used to power the implant. On-board photodetection circuity with a bandwidth of 3.7 MHz is used for forward data telemetry of stimulation parameters. In comparison to implants which utilize inductively coupled coils, laser power delivery enables a high degree of miniaturization and lower surgical complexity. The device presented combines the benefits of implant miniaturization and a flexible stimulation strategy provided by a dedicated stimulator chip. This development provides a route to fully wireless miniaturized minimally invasive implants with sophisticated functionalities.