An electrically tunable-focusing and polarizer-free liquid crystal (LC) lens for ophthalmic applications is demonstrated. The optical mechanism of a LC lens used in human eye system is introduced. The polarizer-free LC lens for myopia-presbyopia based on artificial accommodation is demonstrated. The continuously tunable-focusing properties of the LC lenses are more practical in applications for different visional conditions of people. The concept we proposed can also be applied to another types of lenses as long as the focusing properties are tunable. The concept in this paper can also be extensively applied to imaging systems, and projection systems, such as cameras in cell phones, pico projectors, and endoscopes.
Development of liquid crystal (LC) lenses is limited by the power law. The aperture size of LC lenses is traded for the lens power. In this letter, we prove theoretically and experimentally that the aperture size is not limited by the power law based on a polarizer-free LC lens exploiting an embeddedmultilayered structure. By adding numbers of LC layers, the aperture size of the LC lens can be enlarged without lowering the tunable lens power. The optical theory of the polarization independence of the LC lens is derived. The wavefronts are measured after light propagates through the LC lens to discuss the polarization independence and image adjustment. The impact of this study is to show the possibility of LC lenses with large aperture size for wearable devices and ophthalmic applications.Index Terms-Liquid crystal lens, ophthalmic lens, polarizer free.
1041-1135
We proposed an electrically assisting crystal growth of blue phase liquid crystals (BP-LCs) to generate uniform crystal orientation of BP-LCs. With an applied electric field, a phase transition from BP-LCs to focal conic state and homeotropic state occurs. As the electric field is removed, the crystal orientation of [220] quickly dominates the crystal growth process and other crystal orientations grow less at the same time. The BP-LCs with a single crystal orientation can be achieved with multiple cycles of the electrical treatment. We also provide a possible mechanism of crystal growth with electrical treatment which is applicable for both BP-LCs and PSBP-LCs. In addition, we conclude that the hysteresis effect is mainly affected by the domain size of PSBP-LCs rather than uniformity of crystal orientation. This study helps further understanding of the origin of hysteresis effect in PSBP-LCs which is important for development of many BP-LCs based photonic devices, such as micro lenses, displays, and lasers.
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.
We propose a novel 2-in-1 pattern projector, which consists of a Dot projector and an LC diffuser. The LC diffuser is made of switchable Microlens Arrays (MLA) based on geometric phase. The LC diffuser can switch between "no lens power" and "MLA" mode. In "no lens power" mode, the Dot pattern is not affected by the LC diffuser. In "MLA" mode, the focused Dot pattern is "blurred" by the MLA, which generates the Flood pattern. The eigen mode of geometric phase MLA is carefully designed to achieve polarizer free modulation. We implement this novel modulation concepts with the world smallest and 1 st ever reflowable LC cell. We made a record of 3x3mm LC cell with our in-house IJP system. The optical efficiency is over 95%, and the switching time is less than 5ms.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.