Asymmetric Wireless Power Transfer with a Flexible Contact Lens Inductor

This paper reports the microfabrication of a Galinstan-based flexible coil on a contact lens and its preliminary use for wireless power transfer onto a smart contact lens. The Galinstan-based coil provides accommodation against physical deformation of a contact lens by maintaining electrical conductivity under strains due to its semi-fluidic nature. The fabricated Galinstan-coils successfully demonstrated post-deformation tolerance up to 166.67% strain. The fabricated contact lens prototype with a Galinstan-coil showed the maximum wireless power reception of 32.4 μW with a power efficiency of 0.75% from an external coil located 5 mm away within a frame of eyeglasses.