Large aperture 0 D-2.50 D tunable liquid crystal (LC) lens based on segmented phase profile for tunable focus application

There is a need for a tunable lens technology in AR/VR head mounted displays to solve the accommodation-convergence mismatch issue. Liquid crystal lens technology is one of the promising approaches to achieve a simple, low cost and compact design. However, it is challenging to make a lens with a 5 cm aperture with the required variable power range of 0 D to 2.50 D, with an acceptable switching speed. In the device considered here, we use multiple cell design with segmented phase profile to achieve a tunable focus ability with switching speed under 500 ms. To simplify the electronics of the device, inner-ring resistor network have been used between concentric electrodes. Previously, the effect of the electrode gaps has been studied and the improvement with floating electrodes demonstrated for lower power and smaller aperture (2 cm) LC lenses. In this paper, the effect of the fringing electric fields associated with the discrete electrodes are explored through modeling and imaging characterization, and an improved fabrication process are detailed.