Concentrating Photovoltaic System Using a Liquid Crystal Lens

Tsou, Yu-Shih; Lin, Yi-Hsin; Wei, An-Chi

doi:10.1109/lpt.2012.2224857

Cited by 24 publications

(19 citation statements)

References 19 publications

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“…From the relation between the output power density and the voltage, we chose the maximum output power density defined as P out . 8 We measured P out as a function of the concentration ratio of the liquid lens by applying voltage under different sunlight condition (S), as shown in Fig. 4(a).…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we demonstrated a concept of a CPV system with a liquid crystal (LC) lens whose concentration ratio is adjustable in order to overcome the effect of insufficient photocurrents and the effect of the series resistance under different sunlight conditions. [8][9][10][11][12][13][14][15][16][17][18][19] As a result, the output electric power of such a CPV system is maximal and static under different sunlight conditions. Although the CPV system generates high electric power indoors as well as outdoors, it still requires an extra sun tracker for the sun movement, such as a positional shifter for the LC lens.…”

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confidence: 99%

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A droplet manipulation on a liquid crystal and polymer composite film as a concentrator and a sun tracker for a concentrating photovoltaic system

Tsou

Chang

Lin

2013

Journal of Applied Physics

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We demonstrate a droplet manipulation on a liquid crystal and polymer composite film (LCPCF) as a concentrator and a sun tracker for a concentrating photovoltaic (CPV) system with a steady output electric power. The CPV system adopts a liquid lens on LCPCF whose curvature is not only tunable but position is also bistably switchable based on liquid crystal orientations on LCPCF. The change of curvature of the liquid lens results in a tunable concentration ratio which helps to increase photocurrent at a low illumination and prevent the effect of the series resistance at a high illumination. Moreover, the change of the position of the liquid lens helps to track sun owing to sun movement. Therefore, the output power of such a system is steady no matter the sunlight condition and the angle of incident light. The operating principles and experiments are investigated. The concept in this paper can be extended to design optical components for obtaining steady output power of the solar cell at indoor or outdoor use and also tracking sunlight.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

A droplet manipulation on a liquid crystal and polymer composite film as a concentrator and a sun tracker for a concentrating photovoltaic system

Tsou

Chang

Lin

2013

Journal of Applied Physics

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“…Besides ophthalmic lens, the LC lenses have many applications, such as the imaging systems of portable devices, pico-projection systems, holographic projection systems, solar cells, ophthalmic lenses for myopia/presbyopia and endoscopic systems [33,[46][47][48][49][50][51]. In the imaging system, LC lenses can help to realize autofocusing system and optical zoom system for the portable devices, such as cell phones and cameras [46].…”

Section: Ophthalmic Lenses Using Nematic Liquid Crystalsmentioning

confidence: 99%

“…As to the endoscopic system, a LC lens can be adopted to electrically enlarge the depth-of-field of the endoscopic system [50]. LC lenses can also be used as a concentrator and a sun tracker in a concentrating photovoltaic (CPV) system to stabilize the output power of CPV system [48,51]. An active eyewear device is a future trend.…”

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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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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“…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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Concentrating Photovoltaic System Using a Liquid Crystal Lens

Cited by 24 publications

References 19 publications

A droplet manipulation on a liquid crystal and polymer composite film as a concentrator and a sun tracker for a concentrating photovoltaic system

A droplet manipulation on a liquid crystal and polymer composite film as a concentrator and a sun tracker for a concentrating photovoltaic system

Liquid Crystals for Bio-medical Applications

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

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