Tunable-focus microlens arrays using nanosized polymer-dispersed liquid crystal droplets

Ren, Hongwen; Fan, Yun‐Hsing; Lin, Yi‐Hsin; Wu, Shin Tson

doi:10.1016/j.optcom.2004.11.033

Cited by 116 publications

(38 citation statements)

References 15 publications

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“…Various approaches for fabricating LC microlens array have been proposed. The common is to create a gradient refractive index distribution among LC directors either by an inhomogeneous electric field [9,10,[15][16][17]20,22,23,54] or by an inhomogeneous LC morphology [11][12][13][14]18,19,21,55,56].…”

Section: Principlesmentioning

confidence: 99%

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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: Principlesmentioning

confidence: 99%

“…In 2005, Ren et al demonstrated a fast-response microlens array using nanosized PDLC droplets [54], as Figure 2 shows. UV-curable monomer NOA65 is first molded to form plano-concave microlens arrays on the bottom ITO substrate.…”

Section: Microlens Using Nanosized Polymer-dispersed Liquid Crystal Dmentioning

confidence: 99%

Fast-Response Liquid Crystal Microlens

Liu

et al. 2014

Micromachines

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“…For example, electrically driven H-PDLCs demand a high electric field (10−20 V/ µm) due to the high surface area to volume ratio of small LC droplets. [20][21][22] This becomes problematic because the wholly organic nature of H-PDLC devices makes them vulnerable to high electric fields, thereby forestalling practical application. In addition, optically driven devices show a propensity for poor optical contrast.…”

Section: Introductionmentioning

confidence: 99%

Holographically Formed, Acoustically Switchable Gratings Based on Polymer-Dispersed Liquid Crystals

Liu

Ding

et al. 2013

SLAS Technology

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“…13 It was previously reported that variablefocus liquid microlenses actuated by thermo-sensitive hydrogel could be formed on curved surfaces.…”

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Electrowetting-driven variable-focus microlens on flexible surfaces

Jiang

2012

Applied Physics Letters

100

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We demonstrate a flexible, electrowetting-driven, variable-focus liquid microlens. The microlens is fabricated using a soft polymer polydimethylsiloxane. The lens can be smoothly wrapped onto a curved surface. A low-temperature fabrication process was developed to reduce the stress on and to avoid any damage to the polymer. The focal length of the microlens varies between À15.0 mm to þ28.0 mm, depending on the applied voltage. The resolving power of the microlens is 25.39 line pairs per mm using a 1951 United States Air Force resolution chart. The typical response time of the lens is around 50 ms. V C 2012 American Institute of Physics.[http://dx.doi.org/10.1063/1.4726038]Microlenses are important components in modern miniaturized optical systems.1-9 Among these microlenses, emerging liquid-based variable-focus microlenses are of special importance, because they do not require complicated mechanical systems to adjust optical performance, and they are widely used in photonics, display and biomedical systems.1-4 Meanwhile, microlenses made on flexible and curved substrates could have significant advantages over microlenses on flat substrates in improving the field of view (FOV) 5,6 and creating three-dimensional (3-D) effect. 7,8 For example, microlenses have been fabricated on spherical surfaces as artificial compound eyes.9,10 Current microlenses can be either tunable in focus [1][2][3][4] or made on curved surfaces, 9,11 but not both. Pressure-based variable-focus microlenses require an external mechanical control system and are difficult to be extended to a lens array.12 Tunable lenses based on phase modulation have relatively small magnitude of change in the focal length due to material properties. 13 It was previously reported that variablefocus liquid microlenses actuated by thermo-sensitive hydrogel could be formed on curved surfaces.6 However, they have complicated structures and suffer long response time due to their actuation mechanisms. Robustness and quick response are both of importance to any optical system. Benefitting from short response time, low electrical power consumption, compact structure and the robustness under voltage cycling, electrowetting-driven liquid microlenses have drawn much attention and have been commercialized. 1,14-16 However, traditional electrowetting microlenses are normally fabricated on rigid substrates, such as glass, silicon, and polyethylene terephthalate, 1,14-17 and are consequently not compatible with curved surfaces. Flexible electrowetting microlenses could bring electrowetting lenses into a broader field of applications.Here, we present an electrowetting-driven liquid microlens fabricated on a flexible polymer polydimethylsiloxane (PDMS). The lens has a thin soft polymer substrate, which can be smoothly wrapped on a curved surface, e.g., spherical or cylindrical surfaces. As demonstration, a lens has been made on the surface of a contact lens to show its flexibility. We also describe the processing steps and the materials used for a low-temperature fabrication pr...

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Tunable-focus microlens arrays using nanosized polymer-dispersed liquid crystal droplets

Cited by 116 publications

References 15 publications

Fast-Response Liquid Crystal Microlens

Fast-Response Liquid Crystal Microlens

Holographically Formed, Acoustically Switchable Gratings Based on Polymer-Dispersed Liquid Crystals

Electrowetting-driven variable-focus microlens on flexible surfaces

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