Adjustable liquid-crystal microlenses with homeotropic orientation

Gvozdarev, A.; Nevskaya, G. E.; Yudin, I. B.

doi:10.1364/jot.68.000682

Cited by 10 publications

(4 citation statements)

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“…By minimizing the total free energy, the equilibrium LC director distribution could be obtained. The vector method is a simple way and proved to be in effect [12,13]. According to Frank-Oseen theory, the Gibbs free energy density could be expressed as:…”

Section: Numerical Methods and Physical Modelmentioning

confidence: 99%

“…Among the above mentioned approaches, the hole patterned electrode method is relatively preferable because of its low operating voltage, high numerical aperture, ease of fabrication and excellent capabilities of tunable focal length [9,10]. Although, according to some previous works, the occurrence of disclination lines often deteriorated the optical performance of the liquid crystal microlens, and the cause was usually attributed to the formation of inverse domain and tilt wall [11][12][13]. Even more time would be needed to tune the voltage controllable focal length.…”

Section: Introductionmentioning

confidence: 99%

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Modeling and design of an optimized patterned electrode liquid crystal microlens array with dielectric slab

Zhao

Liu

Zhang

et al. 2013

Optik

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Section: Numerical Methods and Physical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling and design of an optimized patterned electrode liquid crystal microlens array with dielectric slab

Zhao

Liu

Zhang

et al. 2013

Optik

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“…Early reports of the homeotropic alignment geometry in liquid crystal lenses was constrained to devices with parallel substrates and gradient index [8,9] or diffractive lenses [10]. Recently, however, Syed et al reported such an alignment used in a curved contact lens geometry [4] for the first time.…”

Section: Homeotropic Aligned Liquid Crystal Contact Lensesmentioning

confidence: 99%

Liquid crystal contact lenses with graphene electrodes and switchable focus

Gleeson

Kaur

2016

MRS Advances

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Presbyopia is a ubiquitous age-related disability of the eye, affecting an estimated 1.04 billion people worldwide, reducing their ability to focus on nearby objects. The various solutions to this inevitable vision deterioration are not compromise-free, with a growing need for approaches beyond conventional spectacles. The research motivation for this work is the unique solution offered by liquid crystal (LC) contact lenses to create compromise-free vision across the whole field of view. The distinctive property of LC lenses is that they are switchable, with the application of a voltage activating the lens. The change in focal power is facilitated via a voltagedependent change in refractive index of the LC. We have successfully demonstrated several versions of electrically switchable LC contact lenses with variable additional optical power of up to +3.00 D, ideal for the correction of presbyopia.This paper offers a review of the optical and electro-optical performance recently demonstrated for the different modes of operation realized in nematic systems, including planar (homogeneous) and vertically aligned (homeotropic) aligned devices. The change in optical power obtained depends on the choice of geometry and LC material. A material with higher birefringence allows a thinner LC-lens layer to achieve a particular focal power. In the homeotropic geometry, the refractive index of the LC layer is a minimum in the 'off' state (ordinary refractive index, ) and the mode is polarization-independent, offering a significant advantage over planar lens designs. The construction is also simplified as only one alignment layer needs to be rubbed. Depending on the geometry used, continuously variable changes in focal power of up to +3.00D have been achieved. The response time of the lenses can be better than half a second, achieved with small applied voltages of . A further important stage in the optimization of the contact lenses is the inclusion of graphene as the electrodes. Conventional ITO electrodes are too brittle for these flexible optical systems. The paper also reviews the successful incorporation of graphene into the lenses, with excellent optical and electro-optical results. The device demonstrates the huge potential of graphene in an unconventional liquid crystal device geometry that includes curvature over a relatively large area.

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“…In actuality, according to some previous works, disclination lines were often reported to occur, and the cause was usually attributed to the formation of the inverse domain and the tilt wall [11][12][13]. The occurrence of disclination lines changed the liquid crystal director orientation and deteriorated the optical performance.…”

Section: Introductionmentioning

confidence: 99%

Tunable liquid crystal microlens array using hole patterned electrode structure with ultrathin glass slab

et al. 2012

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A configuration of hole patterned electrode liquid crystal microlens array with an ultrathin glass slab was fabricated. To reduce the fringing electric field effect and avoid the occurrence of disclination lines, an ultrathin glass slab was introduced between the patterned electrode and liquid crystal layer. The glass slab thickness played an important role in effecting the optical performance of the liquid crystal microlens array. An optimum thickness of 30 μm was selected employing numerical simulation method. Using this method, we demonstrated a microlens array that greatly improved the phase profile and focus power. The dynamic focal range of the liquid crystal microlens array may extend from <1.2 mm to >8 mm and the minimum diameter of the focus spot could be as small as 15 µm.

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Adjustable liquid-crystal microlenses with homeotropic orientation

Cited by 10 publications

References 0 publications

Modeling and design of an optimized patterned electrode liquid crystal microlens array with dielectric slab

Modeling and design of an optimized patterned electrode liquid crystal microlens array with dielectric slab

Liquid crystal contact lenses with graphene electrodes and switchable focus

Tunable liquid crystal microlens array using hole patterned electrode structure with ultrathin glass slab

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