A Review of Electrically Tunable Focusing Liquid Crystal Lenses

Lin, Hung Chun; Chen, Ming Syuan; Lin, Yi‐Hsin

doi:10.4313/teem.2011.12.6.234

Cited by 135 publications

(74 citation statements)

References 78 publications

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“…Therefore, the LC lens could be an ophthalmic lens for myopia-presbyopia. The lens power of the LC lens (P LC (V)) can be expressed as [33]:…”

Section: Ophthalmic Lenses Using Nematic Liquid Crystalsmentioning

confidence: 99%

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Liquid Crystals for Bio-medical Applications

Lin

2014

Topics in Applied Physics

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Thermotropic nematic LCs can modulate light in phases, amplitudes, and polarizations [1]. Many photonic applications based LCs have developed, such as displays, electro-optical switches, lenses, optical vortex generators, variable optical attenuations, solar cells and so on. Thermotropic nematic LCs have great potential in bio-medical applications. In this session, we mainly introduce two the bio-medical applications based on thermotropic nematic LCs: biosensors and ophthalmic lenses. In biosensors, the key is interfacial interactions between biosamples and LC molecules. We will introduce a LC and polymer complex system, the LC and polymer composite film (LCPCF), whose surface free energy is electrically switchable. LCPCF can help to test the sperm quality and high-density-lipoprotein (HDL). In ophthalmic applications, we will introduce the challenges and requirements for design of ophthalmic lenses. A polarizer-free LC lens with large aperture size is also introduced. Biosensors Using Nematic Liquid CrystalsIn general, interfacial interactions between LCs and bio-samples (or sensing targets) are the key to design a biosensor using nematic LCs [2][3][4][5][6][7]. Such an interfacial interaction often causes the re-orientations of LC molecules at the interface. As a result, optical properties of LC change and the change of the orientation of LC can be read out by observing under a polarizing microscopy. LC can optically amplify the biological binding events and help us to study the biology. The main approach is to immobilize thermotropic nematic LC onto a solid surface as a sensing interface for bio-samples. 5CB is a commonly used a LC material for biosensing. In the literatures, 5CB has been proved for sensing many bio-samples,

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“…Therefore, the LC lens could be an ophthalmic lens for myopia-presbyopia. The lens power of the LC lens (P LC (V)) can be expressed as [33]:…”

Section: Ophthalmic Lenses Using Nematic Liquid Crystalsmentioning

confidence: 99%

“…In this way, the aperture size can be enlarged to >10 mm and the phase increases with the number of layers. Figure 15.12 shows the proposed double-layered structure of polarizer-free LC lens [33,45]. LCPCF is the uniaxial polymeric layer in Fig.…”

Section: Ophthalmic Lenses Using Nematic Liquid Crystalsmentioning

confidence: 99%

Liquid Crystals for Bio-medical Applications

Lin

2014

Topics in Applied Physics

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“…term in Equation (4) is related to the focal length (f), inverse of lens power (P) [17,18]. Lens power is the degree that a lens converges or diverges light.…”

Section: Operating Principle and Lens Designmentioning

confidence: 99%

Simulation Study on Polarization-Independent Microlens Arrays Utilizing Blue Phase Liquid Crystals with Spatially-Distributed Kerr Constants

Chen

Chang

et al. 2014

Micromachines

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Polarization independent liquid crystal (LC) microlens arrays based on controlling the spatial distribution of the Kerr constants of blue phase LC are simulated. Each sub-lens with a parabolic distribution of Kerr constants results in a parabolic phase profile when a homogeneous electric field is applied. We evaluate the phase distribution under different applied voltages, and the focusing properties of the microlens arrays are simulated. We also calculate polarization dependency of the microlenses arrays at oblique incidence of light. The impact of this study is to provide polarizer-free, electrically tunable focusing microlens arrays with simple electrode design based on the Kerr effect.

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“…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.…”

Section: Introductionmentioning

confidence: 99%

“…The lensing effect of the LC phase modulators is caused by the inhomogeneous spatial phase distribution originated from the inhomogeneous orientation distribution of the LC molecules, which can be controlled by the applied electric fields. 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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A Review of Electrically Tunable Focusing Liquid Crystal Lenses

Cited by 135 publications

References 78 publications

Liquid Crystals for Bio-medical Applications

Liquid Crystals for Bio-medical Applications

Simulation Study on Polarization-Independent Microlens Arrays Utilizing Blue Phase Liquid Crystals with Spatially-Distributed Kerr Constants

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

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