Large aperture and polarizer-free liquid crystal lenses for ophthalmic applications

Abstract

Large aperture and polarizer-free liquid crystal lenses (LC lenses) based on a double-layered structure for ophthalmic applications are demonstrated. The polarizer-free LC lens functions as both of a positive lens and a negative lens with large aperture size of 10mm. The lens power is electrically and continuously tunable ranging from -1.32Diopter to 1.83 Diopter. To demonstrate the polarization independency, the wavefronts of the LC lenses under different polarized light were measured and discussed. The detail operations of the applied voltage and frequency are also discussed. The imaging performance of the LC lens is also evaluated. This study provide a detail understanding of the polarizer-free LC lenses based on a double-layered structure.

Orientation fluctuation in liquid crystal lenses

“…Besides the LC lens in Fig. 1(a), we also fabricated the double-layered structure we proposed in 2014 for comparison 19 . The structure is depicted in Fig.…”

“…fabricated the double-layered structure we proposed in 2014 for comparison. 19 The structure is depicted in Fig. 1(b) whose LC material in the LC layers was LCM1790 (LCMatter Corp., LCM-1790, Δn ¼ 0.4172 for λ ¼ 589 nm at 21°C) and the separator was the LCP layer with thickness of 50 microns.…”

Optimization of liquid crystal devices based on weakly conductive layers for lensing and beam steering

“…The typical thickness of the LC layer is in the order of a few lm up to maximum a few tens of lm, while the lateral dimensions range from tens of lm 16 to several millimeter. 13 With this approximation, we need to find an effective permittivity of the liquid crystal layer which is position dependent: e eff ðx; yÞ. This effective permittivity can be calculated by stating that the z-component of the dielectric displacement should be constant along the thickness of the LC layer for every (x,y)-position: D z ¼ e zz ðzÞE z ðzÞ.…”

“…Due to the combined effect of the resistivity of the layer and the capacitance of the LC layer, the uniform weakly conductive layer leads to a spatially varying effective voltage profile. Such a weakly conducting layer approach can be used for tunable lens applications [11][12][13][14] but also for beam steering devices. 15,16 The sheet resistance of weakly conductive layers is an important parameter in the design of several types of devices.…”