Thermally actuated tunable liquid microlens with sub-second response time

Ashtiani, Alireza Ousati; Jiang, Hongrui

doi:10.1063/1.4820772

Cited by 24 publications

(22 citation statements)

References 17 publications

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“…Every laser pulse could generate a single concave microlens, and over 2.78 million microlenses were formed on a PDMS surface within 50 min. Compared to the above solid microlens, liquid lens is also an important type of lenses and has some crucial applications due to the advantages of economical materials, simple preparation process, and easily tunable focal length . The formation of liquid lens is based on the surface tension of a liquid droplet (e.g., water) to form a part‐sphere shape on a solid substrate.…”

Section: Functions and Applicationsmentioning

confidence: 99%

A Review of Femtosecond‐Laser‐Induced Underwater Superoleophobic Surfaces

Yong

Chen

Yang

et al. 2018

Adv Materials Inter

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Section: Functions and Applicationsmentioning

confidence: 99%

A Review of Femtosecond‐Laser‐Induced Underwater Superoleophobic Surfaces

Yong

Chen

Yang

et al. 2018

Adv Materials Inter

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“…In this regard, smart materials such as photopolymers [20] and dielectric elastomers (DEs) [21][22][23] have been employed to seal liquids in a chamber, and such systems when driven by blue-light irradiation or an operation voltage can reshape the lens profile, thereby resulting in change in the focal length. Various driving approaches based on fluidic pressure [24][25][26], acoustic radiation [27], electrochemistry [28], thermal effects [29,30], environmentally adaptive hydrogel [31], and other methods are currently available.…”

Section: Introductionmentioning

confidence: 99%

Dielectric-elastomer-based fabrication method for varifocal microlens array

2017

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We report on a method to fabricate a varifocal microlens array that employs a dielectric elastomer (DE) sandwiched between two electrodes as the lens material. The microlens array is patterned on the electrode plates, and when the electrodes are subjected to a controllable operating voltage, the DE material is "squeezed" by the Maxwell force to deform the lens array pattern, thus resulting in curvature deformation yielding a tunable lens profile. The tunable focal length performance ranges from 950 mm to infinity. When compared with liquid-filled lenses, solid-based varifocal lenses are more robust to thermal expansion, gravity, and vibrational motion. Our approach can be utilized in applications such as machine vision systems.

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“…We recently reported a thermoelectric (TE) driven liquid microlens which relies on the thermal expansion and contraction of the water inside a chamber to drive the lens. 25,26 With the aid of a closed-loop driver and bi-directional heat pumping mechanism, our microlens showed sub-second thermal response time. In this paper, we present a comprehensive study about the microlens structure, fabrication steps, optical characteristic, and finally thermal behavior of the microlens.…”

Section: Introductionmentioning

confidence: 99%

Tunable microlens actuated via a thermoelectrically driven liquid heat engine

Ashtiani

Jiang

2014

Journal of Applied Physics

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We have developed a thermally actuated liquid microlens. An embedded thermoelectric element is used to actuate the liquid based heat engine. A closed-loop system is harnessed to drive and stabilize the temperature of the heat engine. Direct contact between the thermoelectric device and the water results in greatly improved, sub-second thermal rise time (0.8 s). The water based heat engine reacts to the variation in the temperature via expansion and contraction. In turn, the shape of a pinned water-oil meniscus at a lens aperture is deformed in response to the net volume change in the water, creating a tunable microlens. A method to fabricate microfluidic devices with relatively high thickness (250-750 lm) and large length-to-depth aspect ratio (280:1) was developed and used in the process. After fabrication and thermal calibration, optical characteristic of the microlens was assessed. Back focal length of the microlens was shown to vary continuously from À19.6 mm to À6.5 mm as the temperature increased from 5 C to 35 C. A thin film air was further introduced to insulate the heat engine from the substrate to protect the microlens area from the temperature fluctuation of the heat engine, thus preventing the change of the refractive indices and thermally induced aberrations. Wavefront aberration measurement was conducted. Surface profile of the microlens was mapped and found to have a conical shape. Both 3-dimensional and 1-dimensional thermal models for the device structure were developed and thermal simulation of the device was performed. V

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Thermally actuated tunable liquid microlens with sub-second response time

Cited by 24 publications

References 17 publications

A Review of Femtosecond‐Laser‐Induced Underwater Superoleophobic Surfaces

A Review of Femtosecond‐Laser‐Induced Underwater Superoleophobic Surfaces

Dielectric-elastomer-based fabrication method for varifocal microlens array

Tunable microlens actuated via a thermoelectrically driven liquid heat engine

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