Photopolymerized self-assembly microlens arrays based on phase separation

Huang, Li-Chun; Lin, Tzu‐Chieh; Huang, Chao-Yuan; Chao, Chih‐Yu

doi:10.1039/c0sm01013h

Cited by 11 publications

(7 citation statements)

References 15 publications

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“…In fact many procedures have been developed for assembly arrayed microlenses with a variety of materials. For example, swellable polymer microlenses upon exposure to solvents create a tunable range of focal lengths [9], or also the generation of microlenses by virtue of the photopolymerization [10], [11] wherein the employment of a surfactant has broadened the range of substrates for the microlens formation [12]. Recently alternative methods have been proposed for the fabrication of microlens arrays utilizing the electrohydrodynamic (EHD) patterning technique in case of a liquid crystalline polymer [13].…”

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confidence: 99%

Electrohydrodynamic Assembly of Multiscale PDMS Microlens Arrays

Vespini

Gennari

Coppola

et al. 2015

IEEE J. Select. Topics Quantum Electron.

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In this paper, we introduce an easy multiscale approach for the fabrication of polymer microlens arrays through a self-assembling process driven by the electrohydrodynamic (EHD) pressure. This method represents a simple alternative to the conventional soft lithography techniques. A thin layer of liquid polymer is deposited on a microengineered ferroelectric crystal and can be self-assembled and cross-linked in a single-step process as a consequence of the pyroelectric effect activated by simply heating the substrate. Although the EHD instability induced by the pyroelectric effect was discovered in principle few years ago, here we demonstrate a systematic investigation for fabrication of microlens arrays in a multiscale range (i.e., between 25 to 200 μm diameter) with high degree of uniformity. By controlling the polymer instability driven by EHD, we report on two different microoptical shapes can be obtained spontaneously, i.e., spherical or toroidal. Here, we show how the geometrical properties and the focal length of the lens array are modulated by controlling two appropriate parameters. Such microlenses can be useful also as polymer patterned arrayed microstructures for optical data interconnections, OLEDs efficient light extraction, concentrating light in energy solar cells, imaging and 3-D display solutions, and other photonics applications.

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confidence: 99%

Electrohydrodynamic Assembly of Multiscale PDMS Microlens Arrays

Vespini

Gennari

Coppola

et al. 2015

IEEE J. Select. Topics Quantum Electron.

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“…Meanwhile, the enhancement of scanning speed will slightly lead to the enlargement of diameter and reduction of sage height. Secondly, the focal length ( f ) and NA of MLA can be deduced from diameter ( D ) and sag height ( h ) following the equations 34 , where n ( = 1.45) is the value of the refractive index of the fused silica at wavelength of 632 nm. Hereby, the focal length f slightly declines as the etching time rises, and obviously goes up by accelerating the scanning speed, which is due to the increase of the MLA’s diameter.…”

Section: Resultsmentioning

confidence: 99%

Quasi-periodic concave microlens array for liquid refractive index sensing fabricated by femtosecond laser assisted with chemical etching

Zhang

Wang

Yin

et al. 2018

Sci Rep

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In this study, a high-efficiency single-pulsed femtosecond laser assisted with chemical wet etching method has been proposed to obtain large-area concave microlens array (MLA). The quasi-periodic MLA consisting of about two million microlenses with tunable diameter and sag height by adjusting laser scanning speed and etching time is uniformly manufactured on fused silica and sapphire within 30 minutes. Moreover, the fabricated MLA behaves excellent optical focusing and imaging performance, which could be used to sense the change of the liquid refractive index (RI). In addition, it is demonstrated that small period and high RI of MLA could acquire high sensitivity and broad dynamic measurement range, respectively. Furthermore, the theoretical diffraction efficiency is calculated by the finite domain time difference (FDTD) method, which is in good agreement with the experimental results.

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“…Smaller f # means better gathering power. 31 Moreover, in view of the versatility of this strategy, larger f # and smaller n T would be achieved by using a suitable liquid material with a lower capillary number.…”

Section: A Large Fov and Varifocal Abilities For Smart Biomimetic Eyesmentioning

confidence: 99%