Numerical Investigation on Magnetically Actuated Tunable Micro Liquid Lens

Abstract

In this paper, magnetically actuated tunable liquid lens is fundamentally studied to have further potential application scope in research, industrial, aeronautical and astronautical areas. The magnetic field, which is generated by a magnetic potential applied to the permanent magnet domain, distributes non-uniformly in the computational domain and generates magnetic field force to obtain the deformation of the ferrofluid droplet. Consequently, the light-transmitting droplet deforms due to direct contact with the ferrofluid droplet by a connecting channel. The combined effects of gravitational, frictional, interfacial and pressure-driven force make light-transmissive droplet to be a programmable liquid lens. The light-transmissive droplet exhibits changes in the curvature of the contour, which results in different focal lengths for realizing the variable-focus liquid lens. This work focus on the driven mechanism by the magnetic force for a better understanding. The performance is numerically studied for a magnetically actuated varifocal liquid lens by finite element method. The results are presented individually for the distribution of magnetic and flow field, and light refraction.