Electrically tunable-focusing and polarizer-free liquid crystal lenses for ophthalmic applications

Lin, Yi-Hsin; Chen, Hung-Shan

doi:10.1364/oe.21.009428

Cited by 109 publications

(69 citation statements)

References 20 publications

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“…They are expected to be essential optical devices with widespread applications. Generally speaking, LC lenses can be divided into two categories according to their aperture size: those with a large aperture size (>1 mm) are suitable for portable devices, such as pico projectors, imaging system for cell phones, endoscopic system, and ophthalmic lenses [4][5][6][7][8], while those with a small aperture size (<1 mm) are suitable for microlens arrays and their applications include image processing [9][10][11][12][13][14][15][16][17][18][19], optical communication [20,21], lab on a chip, switchable 2D/3D displays [22,23], etc. The progresses of LC lenses with a large aperture size have been reviewed by Fowler et al in 1990 [24] and more recently by Lin et al in 2011 [25].…”

Section: Introductionmentioning

confidence: 99%

Fast-Response Liquid Crystal Microlens

Liu

et al. 2014

Micromachines

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Electrically tunable liquid crystal microlenses have attracted strong research attention due to their advantages of tunable focusing, voltage actuation, low power consumption, simple fabrication, compact structure, and good stability. They are expected to be essential optical devices with widespread applications. However, the slow response time of nematic liquid crystal (LC) microlenses has been a significant technical barrier to practical applications and commercialization. LC/polymer composites, consisting of LC and monomer, are an important extension of pure LC systems, which offer more flexibility and much richer functionality than LC alone. Due to the anchoring effect of a polymer network, microlenses, based on LC/polymer composites, have relatively fast response time in comparison with pure nematic LC microlenses. In addition, polymer-stabilized blue phase liquid crystal (PS-BPLC) based on Kerr effect is emerging as a promising candidate for new photonics application. The major attractions of PS-BPLC are submillisecond response time and no need for surface alignment layer. In this paper, we review two types of fast-response microlenses based on LC/polymer composites: polymer dispersed/stabilized nematic LC and polymer-stabilized blue phase LC. Their basic operating principles are introduced and recent progress is reviewed by examples from recent literature. Finally, the major challenges and future perspectives are discussed. OPEN ACCESSMicromachines 2014, 5 301

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Section: Introductionmentioning

confidence: 99%

Fast-Response Liquid Crystal Microlens

Liu

et al. 2014

Micromachines

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“…This can be solved by using many other structures of LC lens operated with a driving voltage below 10 V rms [10,21]. Moreover, the optical efficiency can be enhanced by using polarization independent LC phase modulator, including double layered type, residual phase type or mixed type [17,20,[22][23][24][25][26][27][28][29][30].…”

Section: Experiments and Discussionmentioning

confidence: 99%

“…The focal length of such a LC phase modulator or LC lens can be tunable as a positive lens or a negative lens depending on the electric fields [10,11]. LC lenses have various applications including image systems [12], pico-projector systems [13], optical zoom systems [14], concentrated photovoltaic systems [15], holographic systems [16], and ophthalmic lens [17].…”

Section: Introductionmentioning

confidence: 99%

An Electrically Tunable Liquid Crystal Lens for Fiber Coupling and Variable Optical Attenuation

Lin¹

2014

J Elec Electron Syst

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In this paper, an electrically tunable LC lens for fiber coupling and variable optical attenuation is proposed and demonstrated. The LC lens electrically changes the lens power in order to adjust the beam size incident on the fiber. When the beam size is closed to the core size of the fiber, the LC lens is operated as a lens coupler. When the beam size increases by reducing the lens power, the LC lens is operated as a VOA. After introducing the operating principles, we use a LC lens to experimentally demonstrate the design concept and the results show that the maximum coupling efficiency can be 0.75 and the maximum attenuation can be as large as18 dB. The concept proposed in this paper is not only for LC lenses, but also for other optical components with electrically tunable focusing properties. The study provides a new way to design an optical device for fiber coupling and variable optical attenuation based on electrically tunable focusing optical components. Figure 1a and 1b depict a typical structure of the LC lens with positive and negative lens operations. We use the hole-patterned LC lens to demonstrate the concept [11,12]. In fact, the concept we proposed here can be applied to other structures of LC lenses. The components of the LC lens included three Indium Tin Oxide (ITO) glass substrates, two Polyvinyl Alcohol (PVA) layers for LC alignment, an insulating layer (Norland product Inc. NOA81), and a 50 μm nematic LC layer (Merck MLC-2070, Δn=0.2609). In order to generate an inhomogeneous electric field, the ITO layer in the middle of the glass substrate was etched with a hole and connected to an applied Alternating Current (AC) voltage of V 1 . PVA layers were coated on the glass substrates and mechanically rubbed in one direction to align the LC molecules. As a result, the LC molecules are aligned parallel to the glass substrate (x-direction in Figure 1) as V 1 =V 2 =0V rms and provide zero lens power (i.e. inverse of the focal length) for x-linearly polarized light. Mechanism and Operating Principles AbstractAn electrically tunable Liquid Crystal (LC) lens for both of fiber coupling and variable optical attenuation is demonstrated. The LC lens modulates the beam waist coupling to the fiber by electrically changing the lens power. When the modulated beam waist is close to the core size of the fiber, the LC lens is operated as a lens coupler. When the beam waist increases by reducing the lens power, the LC lens is operated as a Variable Optical Attenuator (VOA) as a result of the corresponding coupling coefficient variation of the transformed beam into a multimode fiber. The study provides a way to design an optical device for fiber coupling and variable optical attenuation based on electrically tunable focusing optical component.

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“…Large 20 mm diameter E-lenses have been designed with LC and electromagnetic force controlled liquid materials with 3 Diopters and ±25 Diopters powers, respectively [32]. A double-layered LC E-lens has been designed that has polarizer-free operations [33]. In addition, aberrations in an astigmatic liquid E-lens have been compensated using a Shack-Hartmann adaptive optics system [34].…”

Section: History Of Electronic Lenses In Human Vision Carementioning

confidence: 99%

Eye Vision Testing System and Eyewear Using Micromachines

2015

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Proposed is a novel eye vision testing system based on micromachines that uses micro-optic, micromechanic, and microelectronic technologies. The micromachines include a programmable micro-optic lens and aperture control devices, pico-projectors, Radio Frequency (RF), optical wireless communication and control links, and energy harvesting and storage devices with remote wireless energy transfer capabilities. The portable lightweight system can measure eye refractive powers, optimize light conditions for the eye under testing, conduct color-blindness tests, and implement eye strain relief and eye muscle exercises via time sequenced imaging. A basic eye vision test system is built in the laboratory for near-sighted (myopic) vision spherical lens refractive error correction. Refractive error corrections from zero up to´5.0 Diopters and´2.0 Diopters are experimentally demonstrated using the Electronic-Lens (E-Lens) and aperture control methods, respectively. The proposed portable eye vision test system is suited for children's eye tests and developing world eye centers where technical expertise may be limited. Design of a novel low-cost human vision corrective eyewear is also presented based on the proposed aperture control concept. Given its simplistic and economical design, significant impact can be created for humans with vision problems in the under-developed world.

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Electrically tunable-focusing and polarizer-free liquid crystal lenses for ophthalmic applications

Cited by 109 publications

References 20 publications

Fast-Response Liquid Crystal Microlens

Fast-Response Liquid Crystal Microlens

An Electrically Tunable Liquid Crystal Lens for Fiber Coupling and Variable Optical Attenuation

Eye Vision Testing System and Eyewear Using Micromachines

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