Integrated Sensor System to Control the Temperature Effects and the Hysteresis on Adaptive Fluid-Membrane Piezoelectric Lenses

We present in this paper an integrated sensor system for closed-loop control of the temperature effects and the hysteresis on the refractive power of an adaptive fluid-membrane piezoelectric lens. The piezoelectric hysteresis and the fluid thermal expansion contribute to a nonlinear response of the lens refractive power defined as a function of the actuation electric field. Hence, a pressure sensor and a temperature sensor are integrated inside the lens to monitor and define the lens refractive power as a function of both the internal fluid pressure and the temperature, thus, allowing for the closed-loop control of the refractive power. The adaptive lens has a refractive power range varying from -16 m-1 to +17 m-1 at 25{\deg}C and from -15 m-1 to +28 m 1 at 75{\deg}C.