This invention relates to controlling the accommodation actuator, such as a Liquid Crystal (LC) cell of a smart contact lens. The optical strength of the LC cell is controlled by varying its supply voltage. The LC cell functions as a capacitor storing the voltage applied to it. When the optical strength is to be decreased, the voltage across the LC cell is reduced by discharging the LC cell. This discharging is advantageously used to recharge the battery that powers the smart contact lens.
Repeated step-wise voltage increases and decreases cause the LC cell to change its optical strength at a frequency that is imperceptible to the human eye. As a result, the accommodation actuator may be perceived by a user as having the same average optical strength across multiple cycles of the accommodation actuator being charged and discharged.
Using a step-wise increase of the supply voltage allows for less power consumption by the accommodation actuator without affecting the optical strength of the contact lens, as perceived by a user.
Publication number: US20150362751
Patent Title: Power Delivery For Accommodation By An Eye-Mountable Device
Publication type: Grant
Publication date: 17 Dec 2015
Filing date: 23 Apr 2015
Inventors: William J. Biederman;
Original Assignee: Google Inc.