Johnson & Johnson
Impedance sensing circuits for ophthalmic devices

Abstract:

The present disclosure relates to sensor systems for electronic ophthalmic devices. In certain embodiments, the sensor systems may comprise a sensor such as an adjustable resistor configured in series with an eye of a user of the electronic ophthalmic device. The sensor systems may comprise a gain stage configured to amplify a signal indicative of a difference between a voltage drop across the eye and the adjustable resistor. The sensor systems may comprise an integrator configured to integrate the amplified signal. A resistance value of the adjustable resistor is configured to cancel a DC component of a resistance of the eye when an electrical current is caused to flow through the eye and the adjustable resistor. As such, the configured resistance value of the adjustable resistor is indicative of an impedance of the eye.