Tunable-focus liquid lens actuated by a novel piezoelectric motor

Abstract

In this paper, a tunable-focus liquid lens driven by a novel piezoelectric motor is proposed for the adaptive application. Compressing the liquid chamber, the curvature of the lens can be changed by increasing the liquid pressure. This mechanism requires the motor to provide a vertical force to deform the lens surface, whose curvature can be decreased and thereby increasing its focus. As a key part of the tunable-focus liquid lens, a novel piezoelectric motor with the compact structure is emphatically developed in this paper. The operation process of the motor is discussed in detail, whose geometrical parameters are calculated by the finite element simulations. And the motor prototype is then fabricated and tested by the experimental platform. The testing results indicate that the motor can operate steadily and continuously, whose maximum linear velocity can reach 0.065 mm/s under the frequency of 11.80 kHz and voltage of 400 $V_{p-p}$ . The measurement shows that the proposed lens driven by the piezoelectric motor can zoom ranged from 9.6 mm to 17.9 mm, which is suitable for adaptive eyeglass application. Compared with other liquid lens, the prototype with a compact structure, easy and low cost fabrication process can provide high-precision adjustment within a certain range. The presented device exhibits well zooming characteristic and stability in the experiment, which also realizes the successful application of piezoelectric motor in the liquid-lens. It shows greatly potential in the adaptive eyeglasses, and may be employed as the mobile system in the near future.