1
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Sun ZP, Xu Z, Liu YC, Wang XD, Yu Y, Xu XY. Polarization Effect and Improvement of the Electroinduced Formation Efficiency of a Highly Viscous Liquid Bridge. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:14977-14983. [PMID: 37812686 DOI: 10.1021/acs.langmuir.3c01842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
In the electroinduced formation of a highly viscous liquid bridge, improving the efficiency of formation is important for industrial applications. This paper presents the preregulation method of the polarization status to shorten the formation time of a liquid bridge. The hindering effect of high viscosity on the polarization of liquid suspensions was investigated. The formation time of the liquid bridge is shortened, and stability is improved by prepolarizing the initial liquid film, with a maximum reduction in the average and standard deviation of times by 12.65 and 2.52 s, respectively. These effects are confirmed at different viscosities and voltages. In addition, this method has no obvious influence on the shape of the liquid bridge. This study provides an approach to improve the electroinduced formation.
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Affiliation(s)
- Zhong-Ping Sun
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Zheng Xu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Yuan-Chun Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Xiao-Dong Wang
- State Key Laboratory of High-performance Precision Manufacturing, Dalian University of Technology, Dalian 116024, China
| | - Yu Yu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Xiao-Yu Xu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
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2
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Fang C, Xu W, Zhu L, Zhuang Y, Zhang D. Superhydrophobic and easy-to-clean full-packing nanopatterned microlens array with high-quality imaging. OPTICS EXPRESS 2023; 31:13601-13612. [PMID: 37157244 DOI: 10.1364/oe.485260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The high-quality imaging and easy cleaning property of microlens array (MLA) are two very important factors for its outdoor work. Herein, a superhydrophobic and easy-to-clean full-packing nanopatterned MLA with high-quality imaging is prepared by thermal reflow together with sputter deposition. Scanning electronic microscopy (SEM) images demonstrate that the sputter deposition method can improve 84% packing density of MLA prepared by thermal reflow to 100% and add nanopattern on the surface of microlens. The prepared full-packing nanopatterned MLA (npMLA) possess clear imaging with a significant increase of signal-to-noise ratio and higher transparency compared with the MLA prepared by thermal reflow. Besides for excellent optical properties, the full-packing surface displays a superhydrophobic property with a contact angle of 151.3°. Further, the full-packing contaminated by chalk dust become easier to be cleaned by nitrogen blowing and deionized water. As a result, the prepared full-packing is considered to be potential for various applications in the outdoor.
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3
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Li J, Wang W, Fu Z, Zhu R, Huang Y. Fabrication of a dual-focus artificial compound eye with improved imaging based on modified microprinting and air-assisted deformation. APPLIED OPTICS 2023; 62:D125-D130. [PMID: 37132777 DOI: 10.1364/ao.476320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Natural compound eyes inspire the development of artificial optical devices that feature a large field of view and fast motion detection. However, the imaging of artificial compound eyes dramatically depends on many microlenses. The single focal length of the microlens array significantly limits the actual applications of artificial optical devices, like distinguishing objects at different distances. In this study, a curved artificial compound eye for a microlens array with different focal lengths was fabricated by inkjet printing and air-assisted deformation. By adjusting the space of the microlens array, secondary microlenses were created between intervals of the primary microlens. The diameter/height of the primary and secondary microlens arrays are 75/25 µm and 30/9 µm, respectively. The planar-distributed microlens array was transformed into a curved configuration using air-assisted deformation. Compared with adjusting the curved base to distinguish objects at different distances, the reported technique features simplicity and is easy to operate. The applied air pressure can be used to tune the field of view of the artificial compound eye. The microlens arrays with different focal lengths could distinguish the objects at different distances without additional components. When the external objects move a small distance, they can be detected by the microlens arrays due to their different focal lengths. It could effectively improve the motion perception of the optical system. Moreover, the focusing and imaging performances of the fabricated artificial compound eye were further tested. The compound eye combines the advantages of monocular eyes and compound eyes, holding great potential for developing advanced optical devices with a large field of view and automatic variable-focus imaging.
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4
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Zhang Q, Guo Z, Ma Z, Wang S, Peng B. Fabricating SU-8 Photoresist Microstructures with Controlled Convexity-Concavity and Curvature through Thermally Manipulating Capillary Action in Poly(dimethylsiloxane) Microholes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:763-770. [PMID: 36598372 DOI: 10.1021/acs.langmuir.2c02614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
We present a simple, robust, and cheap microfabrication method, based on thermally manipulating capillary action in poly(dimethylsiloxane) (PDMS) microholes, for preparing SU-8 curved microstructures. The microstructure morphology including convexity-concavity and curvature can be controlled via tuning the formation temperature. The convex SU-8 microspherical crowns with a height of 40 μm were formed at 10 °C, whereas the concave SU-8 microspherical crowns with a height of 90 μm were formed at 100 °C. The morphology of the microstructures is dictated by the thermally controlled combination of the pressure difference across the interface, contact angle, and surface tension. The fabricated microstructures with a spherical surface can be used as a microlens array or a mold for producing a microlens array. The clear and uniform images were observed using the generated microlens arrays. The equilibrium morphology of the microstructures can be predicted by numerical simulation, which can lessen the number of experiments and thus the design cost. The proposed method has the potential to find applications in industrial fields.
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Affiliation(s)
- Qiushu Zhang
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan611731, China
| | - Zhihao Guo
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan611731, China
| | - Zhinan Ma
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan611731, China
| | - Song Wang
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan611731, China
| | - Bei Peng
- School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan611731, China
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5
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Ghosh S, Chaudhuri S, Roy P, Lahiri D. 4D Printing in Biomedical Engineering: a State-of-the-Art Review of Technologies, Biomaterials, and Application. REGENERATIVE ENGINEERING AND TRANSLATIONAL MEDICINE 2022. [DOI: 10.1007/s40883-022-00288-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Lv G, Tian H, Shao J, Yu D. Pattern formation in thin polymeric films via electrohydrodynamic patterning. RSC Adv 2022; 12:9681-9697. [PMID: 35424937 PMCID: PMC8959450 DOI: 10.1039/d2ra01109c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 03/21/2022] [Indexed: 11/21/2022] Open
Abstract
The free surface of a thin polymeric film is often unstable and deforms into various micro-/nano-patterns under an externally applied electric field. This paper reviews a recent patterning technique, electrohydrodynamic patterning (EHDP), a straightforward, cost-effective and contactless bottom-up method. The theoretical and numerical studies of EHDP are shown. How the characteristic wavelength and the characteristic time depend on both the external conditions (such as voltage, film thickness, template-substrate spacing) and the initial polymer properties (such as rheological property, electrical property and surface tension) is theoretically and experimentally discussed. Various possible strategies for fabricating high-aspect-ratio or hierarchical patterns are theoretically and experimentally reviewed. Aligning and ordering of the anisotropic polymers by EHDP is emphasized. A perspective, including novelty and limitations of the methods, particularly in comparison to some conventional patterning techniques, and a possible future direction of research, is presented.
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Affiliation(s)
- Guowei Lv
- School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipments, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China
- Xi'an Aerospace Chemical Propulsion Co., Ltd. Xi'an 710025 Shaanxi P. R. China
| | - Hongmiao Tian
- State Key Laboratory of Manufacturing Systems Engineering, Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China
| | - Jinyou Shao
- State Key Laboratory of Manufacturing Systems Engineering, Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China
| | - Demei Yu
- School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipments, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China
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7
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High-resolution imaging and fast number estimation of suspended particles using dewetted polymer microlenses in a microfluidic channel. Micron 2021; 151:103148. [PMID: 34562815 DOI: 10.1016/j.micron.2021.103148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 12/25/2022]
Abstract
We have fabricated polymer micro-lens array by self-organized dewetting inside the microchannel, which shows remarkable enhancement in the resolution, contrast and more than 10 times add-on magnification to a microscope. These lenses are demonstrated to resolve sub-micrometer features and detect moving micro-particles when suspension is flown in a microchannel. Polystyrene (PS) micro-lenses are fabricated on a polydimethylsiloxane (PDMS) substrate using the controlled dewetting of PS thin film then this PDMS substrate is used to close the microchannel with inverted micro-lenses on it. An aqueous suspension of polystyrene particles is flown through the microchannel and we have observed the particles through an optical microscope. Focusing and magnification through PS micro-lenses is analyzed to get a quantitative estimate of the particle number density in the solution. This method offers a promising low-cost high throughput solution for determining the approximate number density of flowing particles or suitably stained biological cells. Particularly in a pathology lab it can tremendously increase detection limit by enabling visibility of sub-micrometer pathogens using a standard laboratory microscope.
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8
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Zhang H, Qi T, Zhu X, Zhou L, Li Z, Zhang YF, Yang W, Yang J, Peng Z, Zhang G, Wang F, Guo P, Lan H. 3D Printing of a PDMS Cylindrical Microlens Array with 100% Fill-Factor. ACS APPLIED MATERIALS & INTERFACES 2021; 13:36295-36306. [PMID: 34293853 DOI: 10.1021/acsami.1c08652] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cylindrical microlens arrays (CMLAs) play a key role in many optoelectronic devices, and 100% fill-factor CMLAs also have the advantage of improving the signal-to-noise ratio and avoiding stray-light effects. However, the existing preparation technologies are complicated and costly, which are not suitable for mass production. Herein, we propose a simple, efficient, and low-cost manufacturing method for CMLAs with a high fill-factor via the electric-field-driven (EFD) microscale 3D printing of polydimethylsiloxane (PDMS). By adjusting the printing parameters, the profile and the fill-factor of the CMLAs can be controlled to improve their optical performance. The optical performance test results show that the printed PDMS CMLAs have good image-projecting and light-diffraction properties. Using the two printing modes of this EFD microscale 3D-printing technology, a cylindrical dual-microlens array with a double-focusing function is simply prepared. At the same time, we print a series of specially shaped microlenses, proving the flexible manufacturing capabilities of this technology. The results show that the prepared CMLAs have good morphology and optical properties. The proposed method may provide a viable route for manufacturing large-area CMLAs with 100% fill-factor in a very simple, efficient, and low-cost manner.
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Affiliation(s)
- Houchao Zhang
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Tianyu Qi
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Xiaoyang Zhu
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Longjian Zhou
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Zhenghao Li
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Yuan-Fang Zhang
- Digital Manufacturing and Design Centre, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Wenchao Yang
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Jianjun Yang
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Zilong Peng
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Guangming Zhang
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Fei Wang
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Pengfei Guo
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
| | - Hongbo Lan
- Shandong Engineering Research Center for Additive Manufacturing, Qingdao University of Technology, Qingdao 266520, China
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9
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Cai S, Sun Y, Chu H, Yang W, Yu H, Liu L. Microlenses arrays: Fabrication, materials, and applications. Microsc Res Tech 2021; 84:2784-2806. [PMID: 33988282 DOI: 10.1002/jemt.23818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/21/2021] [Accepted: 05/02/2021] [Indexed: 11/07/2022]
Abstract
Microlenses have become an indispensable optical element in many optical systems. The advancement of technology has led to a wider variety of microlenses fabrication methods, but these methods suffer from, more or less, some limitations. In this article, we review the manufacturing technology of microlenses from the direct and indirect perspectives. First, we present several fabrication methods and their advantages and disadvantages are discussed. Then, we discuss the commonly used materials for fabricating microlenses and the applications of microlenses in various fields. Finally, we point out the prospects for the future development of microlenses and their fabrication methods.
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Affiliation(s)
- Shuxiang Cai
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai, China
| | - Yalin Sun
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai, China
| | - Honghui Chu
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai, China
| | - Wenguang Yang
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai, China
| | - Haibo Yu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, China
| | - Lianqing Liu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, China
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10
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Xu XY, Xu Z, Wang XD, Qin SC, Qian YW, Wang LD, Liu JS. Loading a High-Viscous Droplet via the Cone-Shaped Liquid Bridge Induced by an Electrostatic Force. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2334-2340. [PMID: 33529533 DOI: 10.1021/acs.langmuir.0c03154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In transfer printing, the loaded droplet on the probe has a significant influence on the dispensing resolution. A suitable loading approach for a high-viscous liquid is highly required. Herein, a novel electrostatic loading method is presented, in which the main aim is to control precisely the formation and breaking of a cone-shaped liquid bridge. An experimental device is developed. The influence of electrical and geometric parameters on the feature size of the liquid bridge is investigated in detail. In the formation of the liquid bridge, the increase of voltage or the decrease of the air gap can enhance the electric field intensity, thus reducing the formation period and increasing the initial cone tip diameter of the liquid cone. After the liquid bridge is formed, both the circuit current implying the liquid wetted area on the probe surface and the lifting velocity of the probe are utilized to further regulate the volume of the loaded droplet. Loaded droplets ranging from 60 to 600 pL are obtained via the method with a standard deviation of 4 to 30 pL. Moreover, a dot array is transferred with different loaded droplets. The minimum diameter of the printed dots is about 140 μm with a variation less than 5%. The advantages include the reduced risk of contamination, the droplet-size independent of the size of the probe, and the low cost of the device.
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Affiliation(s)
- Xiao-Yu Xu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Zheng Xu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Xiao-Dong Wang
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Shao-Chun Qin
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Yan-Wen Qian
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Li-Ding Wang
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
| | - Jun-Shan Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China
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11
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Lv G, Hu X, Hao L, Tian H, Shao J, Yu D. Facile Fabrication of a Flexible Patterned Film with Diverse Micro-/Nanostructures via Electrohydrodynamic Patterning. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c04908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Guowei Lv
- School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipments, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, P. R. China
| | - Xiaobing Hu
- College of Chemistry and Chemical Engineering, Shaanxi Province Key Laboratory of Phytochemistry, Baoji University of Arts and Sciences, Baoji 721013, Shaanxi, P. R. China
| | - Lu Hao
- School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipments, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, P. R. China
| | - Hongmiao Tian
- State Key Laboratory of Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, P. R. China
| | - Jinyou Shao
- State Key Laboratory of Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, P. R. China
| | - Demei Yu
- School of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipments, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, P. R. China
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12
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Li J, Wang W, Mei X, Pan A. Designable Ultratransparent and Superhydrophobic Surface of Embedded Artificial Compound Eye with Extremely Low Adhesion. ACS APPLIED MATERIALS & INTERFACES 2020; 12:53557-53567. [PMID: 33176099 DOI: 10.1021/acsami.0c18881] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Real-world implementation of artificial compound eye (ACE) has been limited by its poor transparency and high requirement for the stable Cassie state. In general, the improvement of surface dewetting performance sacrifices the transparency of ACE. Herein, ACE was obtained by an integrated manufacturing technology that combined photolithography, microprinting, and chemical growth. Through skillful manipulation of the fabrication process, dewetting hairs were fabricated on the top of micropillars and around the microlens. The combination of nanohairs and micropillars resulted in outstanding superhydrophobicity (∼170°), pristine lotus effect with low sliding angle (∼1°), and contact angle hysteresis (∼2°). Moreover, the surface showed almost no adhesion under a preload of 4 mN, exhibiting excellent stable Cassie state and antiadhesion performance. Furthermore, dynamic impact showed that the impacting droplet was quickly detached from the surface (contact time ∼14.1 ms) without sticking for We = 60. The designed transparency resulted in high performance of optical unit (∼99%, bare glass for comparison). Moreover, ACE exhibited better focusing and imaging capability under larger aperture diameter than microlens without nanohairs. We envision that this research presents a significant advancement in imparting superhydrophobicity and transparency to a so-far inapplicable family of optical devices for many practical outdoor applications.
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Affiliation(s)
- Jiang Li
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xian 710054, China
- Shaanxi Key Laboratory of Intelligent Robots, Xi'an Jiaotong University, Xian 710049, China
| | - Wenjun Wang
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xian 710054, China
- Shaanxi Key Laboratory of Intelligent Robots, Xi'an Jiaotong University, Xian 710049, China
| | - Xuesong Mei
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xian 710054, China
- Shaanxi Key Laboratory of Intelligent Robots, Xi'an Jiaotong University, Xian 710049, China
| | - Aifei Pan
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xian 710054, China
- Shaanxi Key Laboratory of Intelligent Robots, Xi'an Jiaotong University, Xian 710049, China
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13
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Xu P, Xu M, Lu H, Qiu L. Polyvinyl chloride gels microlens array with a well-controlled curvature obtained by solvent evaporation under DC electric fields. OPTICS EXPRESS 2020; 28:29285-29295. [PMID: 33114831 DOI: 10.1364/oe.404135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
In this paper, polyvinyl chloride (PVC) gels microlens arrays (MLAs) with controllable curvatures were prepared by evaporation of the solvent under DC electric fields. In order to obtain these arrays, the PVC gel solution was first injected into the cofferdam of a ring array patterned electrode substrate. Upon polarization under DC electric field, the electric charge injected from the cathode was carried by the plasticizers towards the anode to accumulate on its surface. After complete evaporation of the solvent, the PVC gels formed stable MLAs. The focal length of the formed MLAs obtained after evaporation of the 100 µL PVC gel solvent under 30 V DC field was 8.68 mm. The focal length of the as-obtained PVC gel-based MLAs can be well-controlled by merely tuning the strength of the electric field or by changing the volume of the PVC gel solution. Thus, it can be concluded that the proposed methodology looks very promising for future fabrication of MLAs with uniform size in larger areas.
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14
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Song F, Niu H, Fan J, Chen Q, Wang G, Liu L. Molecular dynamics study on the coalescence and break-up behaviors of ionic droplets under DC electric field. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113195] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Yuan X, Tang B, Barman J, Groenewold J, Zhou G. Approximately symmetric electrowetting on an oil-lubricated surface. RSC Adv 2020; 10:20257-20263. [PMID: 35520452 PMCID: PMC9054235 DOI: 10.1039/d0ra02405h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/09/2020] [Indexed: 12/24/2022] Open
Abstract
As the most widely used insulator materials in the electrowetting (EW) systems, amorphous fluoropolymers (AFs) provide excellent hydrophobicity, dielectric properties and chemical inertness; however, they suffer from charge trapping during electrowetting with water and the consequent asymmetric phenomenon. In this study, an ultra-thin oil-lubricated AF surface was proposed to release the charge trapping in the dielectric layer and further suppress the polarity-dependent asymmetry during electrowetting. The negative spontaneously trapped charges gathering on the dielectric/water interface with aging time were characterized by various measurements and calculations, which explained the polarity dependence of the asymmetric electrowetting. Approximately symmetric EW curves withstanding water aging were obtained for the oil-lubricated AF surface, confirming the blocking effect on charge trapping induced by the lubricated surface. The improved reversibility of EW with low contact angle hysteresis brought by the oil-lubricated surface was also demonstrated. This study reveals the mechanism behind the asymmetric EW phenomenon and offers an attractive oil-lubricated EW material system for suppressing the charge trapping on the dielectric/water interface, which can significantly improve the manipulation of the EW devices.
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Affiliation(s)
- Xi Yuan
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China
| | - Biao Tang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China
| | - Jitesh Barman
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China
| | - Jan Groenewold
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China.,Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Research Institute, Utrecht University Padualaan 8 3584 CH Utrecht The Netherlands
| | - Guofu Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China.,Academy of Shenzhen Guohua Optoelectronics Shenzhen 518110 P. R. China
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Chen L, Chen G, Liao L, Chen H. Naked-Eye 3D Display Based on Microlens Array Using Combined Micro-Nano Imprint and UV Offset Printing Methods. Molecules 2020; 25:molecules25092012. [PMID: 32344928 PMCID: PMC7248864 DOI: 10.3390/molecules25092012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/18/2020] [Accepted: 04/23/2020] [Indexed: 11/16/2022] Open
Abstract
An optical film integrating microlens array (MLAs) and 3D micro-graphics is an important way to achieve the naked-eye 3D display effect. The 3D micro-graphics is traditionally generated by the micro-nano imprint technology based on precision engraving mold, which leads to high production cost and low production efficiency, and thus restricts the rapid response to production tasks and large-scale popularization and application. In this study, a process scheme for large-scale printing of 3D micro-graphics using UV offset printing based on presensitized (PS) plate was proposed, matching with the MLAs fabricated by micro-nano imprint process to achieve naked-eye 3D display effect. We used the laser confocal microscope to systematically measure and analyze the geometric and optical performance of the fabricated MLAs in terms of height, curvature radius, center distance, spacing, focal length, and numerical aperture, and evaluated the influence of the publishing resolution of the PS plate on the display effect of 3D micro-graphics. The printing quality and display effect of 3D micro-graphics were further improved by adjusting process parameters such as printing speed and printing pressure. The results of the current study demonstrate that the combined application of micro-nano imprint technology based on precision mold and UV offset printing technology based on PS plate can achieve an excellent naked-eye 3D display effect in 360° all angles, which is efficient, cost-saving, and highly flexible.
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Affiliation(s)
- Linyi Chen
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China; (L.C.); (G.C.)
| | - Guangxue Chen
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China; (L.C.); (G.C.)
| | - Liyu Liao
- YUTO R&D Institute, Shenzhen YUTO Packaging Technology Co., Ltd., Shenzhen 518108, China;
| | - Haozhi Chen
- Guangzhou Financial Service Innovation and Risk Management Research Base, South China University of Technology, Guangzhou 510640, China
- Correspondence:
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17
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Li J, Wang W, Mei X, Hou D, Pan A, Liu B, Cui J. Fabrication of Artificial Compound Eye with Controllable Field of View and Improved Imaging. ACS APPLIED MATERIALS & INTERFACES 2020; 12:8870-8878. [PMID: 32011852 DOI: 10.1021/acsami.9b20740] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Many arthropods have compound eyes, which are made up of numerous separate visual units (microlenses) or ommatidia. These natural compound eyes have exceptional optical properties such as wide field of view (FOV), low aberration, and fast motion tracking capability. In this paper, a large-scale artificial compound eye (ACE) is fabricated efficiently using a combination of inkjet printing and air-assisted deformation processes. Both size and geometry of the microlens are controlled via superposed drops on the substrate. The simulation results show that the light intensity of the ACE follows a systematic distribution for tilted incident light, which represents a significant improvement, compared to planar distributed microlenses. We then manufacture ACEs with different heights and diameters, and their FOVs are compared with the theoretically predicted results. The measured FOV was 50°-140°. The acceptance angles for the different ACEs are determined, and their relationship with the ratio of height to radius (H/r) of the microlens is investigated in more detail. Furthermore, the imaging properties of the microlenses with different angles of incidences are studied, which suggest a FOV up to 140° and an acceptance angle of about 50°. The microlens captures images even at an angle of incidence of about 60°. The corresponding distortion in both the x and y directions is also investigated. Our findings provide guidelines for the development and fabrication of ACEs with large FOVs and acceptance angles, which may find applications in military, robotics, medical imaging, and astronomy.
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Affiliation(s)
- Jiang Li
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Wenjun Wang
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Xuesong Mei
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Dongxiang Hou
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Aifei Pan
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Bin Liu
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Jianlei Cui
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
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18
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Mei L, Wang G, Deng J, Xiao J, Guo X. Tunable fabrication of concave microlens arrays by initiative cooling-based water droplet condensation. SOFT MATTER 2019; 15:9150-9156. [PMID: 31674620 DOI: 10.1039/c9sm01333d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Microlens arrays (MLAs), as one of the key features in the optoelectronics field, have attracted a lot of attention recently. Unfortunately, existing fabrication methods of MLAs have many disadvantages, such as complex fabrication procedures and difficult morphology control. This paper presents a low-cost and tunable fabrication approach for concave MLAs on ultraviolet (UV) polymer surfaces. We used condensed water droplets, formed by initiative cooling, as the template for the formation of concave MLAs in this approach. A sacrificial layer of polymer material was introduced to fabricate concave MLAs with different morphology parameters. The three most important parameters of MLAs, i.e. diameter, cross-sectional profile, and packing distance, can be tuned by the proposed novel fabrication approach. By controlling the condensation time of water droplets, we can control the diameter of the concave MLAs. Moreover, the cross-sectional profile can be controlled by replacing the sacrificial layer material to change the interaction among the water droplets, sacrificial polymers, and UV polymers. In addition, the packing distance of the MLAs can also be adjusted by introducing the lateral flow of the sacrificial polymer, which was driven by the additional sacrificial polymer dispensed on the substrate. Furthermore, the UV polymer film with MLAs on its surface was applied for the packaging of high power green LEDs. Consequently, the optical output power of green LED modules is enhanced by 11.4% when using the MLAs at the driving current of 500 mA.
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Affiliation(s)
- Luyao Mei
- National Institute of LED on Si Substrate, Nanchang University, Nanchang 330047, China.
| | - Guangxu Wang
- National Institute of LED on Si Substrate, Nanchang University, Nanchang 330047, China.
| | - Jia Deng
- Department of Systems Science and Industrial Engineering, Binghamton University - State University of New York (SUNY), Binghamton, NY 13902, USA
| | - Junfeng Xiao
- School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xing Guo
- National Institute of LED on Si Substrate, Nanchang University, Nanchang 330047, China.
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19
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Yang Q, Gao B, Xu F. Recent Advances in 4D Bioprinting. Biotechnol J 2019; 15:e1900086. [DOI: 10.1002/biot.201900086] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/23/2019] [Indexed: 01/17/2023]
Affiliation(s)
- Qingzhen Yang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and TechnologyXi'an Jiaotong University Xi'an 710049 P. R. China
- Bioinspired Engineering and Biomechanics Center (BEBC)Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Bin Gao
- Department of Endocrinology, Tangdu HospitalAir Force Military Medical University Xi'an 710038 P. R. China
| | - Feng Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and TechnologyXi'an Jiaotong University Xi'an 710049 P. R. China
- Bioinspired Engineering and Biomechanics Center (BEBC)Xi'an Jiaotong University Xi'an 710049 P. R. China
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20
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Bao L, Pinchasik BE, Lei L, Xu Q, Hao H, Wang X, Zhang X. Control of Femtoliter Liquid on a Microlens: A Way to Flexible Dual-Microlens Arrays. ACS APPLIED MATERIALS & INTERFACES 2019; 11:27386-27393. [PMID: 31268287 DOI: 10.1021/acsami.9b06390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Microlens arrays are key elements for light management in optoelectronic devices. The recent advancement in the wearable intelligent electronics has driven the development of flexible microlenses. In this work, we show a controllable and scalable surface-droplet-based strategy to create unconventional flexible polymer microlens arrays. The technique is underpinned by the morphological transition of femtoliter liquid on the surface of a microlens surrounded by a planar area. We found that the droplet liquid wetted the rim of the microlens first and gradually moved upward to the microlens surface with an increase in the liquid volume. The morphology evolution of the droplet is in good agreement with the predication from our simulations based on the interfacial energy minimization under the condition of the pinned boundary. The shape of the droplet on the microlens is well controlled by the droplet volume, aspect ratio of the microlens, and the interfacial energy of the droplets on the microlens. As a result, the obtained structures of one microlens partially covered by a droplet can be produced in arrays over a large scale, serving as templates for fabricating transparent polymer double microlens arrays for improved light emission from the optoelectronic device.
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Affiliation(s)
- Lei Bao
- School of Engineering , RMIT University , Melbourne , VIC 3001 , Australia
| | - Bat-El Pinchasik
- Department of Physics at Interfaces , Max Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
- School of Mechanical Engineering, Faculty of Engineering , Tel-Aviv University , Ramat Aviv , 69978 Tel-Aviv , Israel
| | - Lei Lei
- School of Engineering , RMIT University , Melbourne , VIC 3001 , Australia
- School of Civil Engineering , Xuzhou University of Technology , Xuzhou , Jiangsu Province 221000 , China
| | - Qiwei Xu
- Department of Electrical and Computer Engineering , University of Alberta , Edmonton , Alberta T6G 2V4 , Canada
| | - Hao Hao
- Department of Chemistry and Biotechnology, School of Science , Swinburne University of Technology , Hawthorn , VIC 3122 , Australia
| | - Xihua Wang
- Department of Electrical and Computer Engineering , University of Alberta , Edmonton , Alberta T6G 2V4 , Canada
| | - Xuehua Zhang
- Department of Chemical & Materials Engineering, Faculty of Engineering , University of Alberta , Edmonton , Alberta T6G 1H9 , Canada
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21
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Chen J, Fritz B, Liang G, Ding X, Lemmer U, Gomard G. Microlens arrays with adjustable aspect ratio fabricated by electrowetting and their application to correlated color temperature tunable light-emitting diodes. OPTICS EXPRESS 2019; 27:A25-A38. [PMID: 30876002 DOI: 10.1364/oe.27.000a25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
We develop a facile, fast, and cost-effective method based on the electrowetting effect to fabricate concave microlens arrays (MLA) with a tunable height-to-radius ratio, namely aspect ratio (AR). The electric parameters including voltage and frequency are demonstrated to play an important role in the MLA forming process. With the optimized frequency of 5 Hz, the AR of MLA are tuned from 0.057 to 0.693 for an increasing voltage from 0 V to 180 V. The optical properties of the MLA, including their transmittance and light diffusion capability, are investigated by spectroscopic measurements and ray-tracing simulations. We show that the overall transmittance can be maintained above around 90% over the whole visible range, and that an AR exceeding 0.366 is required to sufficiently broaden the transmitted light angular distribution. These properties enable to apply the developed MLA films to correlated-color-temperature (CCT)-tunable light-emitting-diodes (LEDs) to enhance their angular color uniformity (ACU). Our results show that the ACU of CCT-tunable LEDs is significantly improved while preserving almost the same lumen output, and that the MLA with the highest AR exhibits the best ACU performance.
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22
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Xu Q, Dai B, Huang Y, Wang H, Yang Z, Wang K, Zhuang S, Zhang D. Fabrication of polymer microlens array with controllable focal length by modifying surface wettability. OPTICS EXPRESS 2018; 26:4172-4182. [PMID: 29475269 DOI: 10.1364/oe.26.004172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/03/2018] [Indexed: 06/08/2023]
Abstract
A straightforward technique for fabricating low-cost microlens arrays with controllable focal length is developed. By harnessing and manipulating the interfacial energy between the liquid-state acrylate resin and the solidified polydimethylsiloxane (PDMS), the surface of the acrylate resin in the PDMS microhole presents a spherical shape and the curvature can be flexibly controlled. With the change of the processing time for the surface modification of the PDMS microholes, the focal length of the concave microlenses varies from -296.3 μm to -67.4 μm. The numerical aperture of 0.45 is realized. The focal length and the aperture of the microlenses are also affected by the diameter of the microholes. The fabricated concave microlens array can be employed as a master to further duplicate convex microlens array. A good image quality can be achieved by using the convex microlens arrays.
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23
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Chen PC, Chang YP, Zhang RH, Wu CC, Tang GR. Microfabricated microfluidic platforms for creating microlens array. OPTICS EXPRESS 2017; 25:16101-16115. [PMID: 28789118 DOI: 10.1364/oe.25.016101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The paper presents a novel and economic manufacturing process for microlens arrays (MLAs). This process uses micromilling machining, PDMS casting, and hybrid bonding between a glass substrate and PDMS membrane to create a microfluidic chip which is used for manufacturing MLAs on a PDMS substrates. MLAs of various diameters were fabricated for experiments, including 1000 μm, 500 μm, and 200 μm. The sag height of the MLAs is easily adjusted by controlling the pressure inside the microchannel to deform the PDMS membrane. Multiple experiments were conducted to characterize the performance of MLAs, the results of which demonstrate: (1) this fabrication process is able to manufacture MLAs with various dimensions and the diameter of an MLAs is determined by the size of micromilling bit and cutting path; (2) the sag height and curvature of MLAs can be controlled by the PDMS membrane thickness and the hydraulic pressure inside the microchannel; (3) an optical system was built to investigate the uniformity of MLAs and the experiment results showed uniform focal length of MLAs; (4) the resulting MLAs magnify tiny objects and significantly enhance the fluorescence signal emitted from the microchannel.
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24
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Zhang D, Xu Q, Fang C, Wang K, Wang X, Zhuang S, Dai B. Fabrication of a Microlens Array with Controlled Curvature by Thermally Curving Photosensitive Gel Film beneath Microholes. ACS APPLIED MATERIALS & INTERFACES 2017; 9:16604-16609. [PMID: 28452461 DOI: 10.1021/acsami.7b00766] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A rapid method is developed for fabricating low-cost and high-numerical-aperture photosensitive-gel microlens arrays (MLAs) with well-controlled curvatures. An UV-curable photosensitive-gel film beneath the microholes of a silicon mold can be flexibly deformed by thermally manipulating the surface tension of the photosensitive gel and the pressure difference across the air-photosensitive-gel interface. The concave interface is then solidified through UV curing, forming a MLA with a concave curvature. MLAs with a focal length ranging from 51.4 to 71.9 μm and a numerical aperture (NA) of 0.49 were fabricated. The photocured MLA has high mechanical and thermal strength and is suitable as a master mold for the further production of convex MLAs. The fabricated microlenses have uniform shapes and smooth surfaces. In a demonstration of imaging and focusing performance, clear and uniform images and focused light spots were observed using concave and convex MLAs.
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Affiliation(s)
- Dawei Zhang
- Engineering Research Center of Optical Instrument and System, the Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology , Shanghai 200093, China
| | - Qiao Xu
- Engineering Research Center of Optical Instrument and System, the Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology , Shanghai 200093, China
| | - Chaolong Fang
- Engineering Research Center of Optical Instrument and System, the Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology , Shanghai 200093, China
| | - Kaimin Wang
- Engineering Research Center of Optical Instrument and System, the Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology , Shanghai 200093, China
| | - Xu Wang
- The Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University , Edinburgh EH14 4AS, U.K
| | - Songlin Zhuang
- Engineering Research Center of Optical Instrument and System, the Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology , Shanghai 200093, China
| | - Bo Dai
- Engineering Research Center of Optical Instrument and System, the Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology , Shanghai 200093, China
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25
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Ahmed R, Yetisen AK, Butt H. High Numerical Aperture Hexagonal Stacked Ring-Based Bidirectional Flexible Polymer Microlens Array. ACS NANO 2017; 11:3155-3165. [PMID: 28252935 DOI: 10.1021/acsnano.7b00211] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Flexible imprinted photonic nanostructures that are able to diffract/focus narrow-band light have potential applications in optical lenses, filters, tunable lasers, displays, and biosensing. Nanophotonic structures through holography and roll-to-roll printing may reduce fabrication complexities and expenses and enable mass production. Here, 3D photonic nanostructures of a stacked ring array were imprinted on acrylate polymer (AP) over poly(ethylene terephthalate) (PET) substrate through holography and lift-off processes to create a microlens array (MLA). The surface structure of the array consisted of circular nonostepped pyramids, and repeated patterns were in hexagonal arrangements. Stacked-ring-based MLA (SMLA) on a flexible AP-PET substrate showed efficient bidirectional light focusing and maximum numerical aperture (NA = 0.60) with a reasonable filling factor. The nanostructures produced a well-ordered hexagonally focused diffraction pattern in the far field, and power intensities were measured through angle-resolved experiments. The variation of nanostep dimensions (width and height) and the number of steps resulted in different photonic bandgaps, and the arrays produced distance-dependent narrow-band light focusing. The validation of the SMLA was demonstrated through the text, image, and hologram projection experiments. It is anticipated that imprinted bidirectional SMLA over flexible substrates may find applications in optical systems, displays, and portable sensors.
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Affiliation(s)
- Rajib Ahmed
- Microengineering and Nanotechnology Laboratory, School of Engineering, University of Birmingham , Birmingham B15 2TT, United Kingdom
| | - Ali K Yetisen
- Harvard Medical School and Division of Biomedical Engineering, Brigham and Women's Hospital , 65 Lansdowne Street, Cambridge, Massachusetts 02139, United States
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Haider Butt
- Microengineering and Nanotechnology Laboratory, School of Engineering, University of Birmingham , Birmingham B15 2TT, United Kingdom
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26
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Zuo H, Choi DY, Gai X, Luther-Davies B, Zhang B. CMOS compatible fabrication of micro, nano convex silicon lens arrays by conformal chemical vapor deposition. OPTICS EXPRESS 2017; 25:3069-3076. [PMID: 28241523 DOI: 10.1364/oe.25.003069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a novel CMOS-compatible fabrication technique for convex micro-nano lens arrays (MNLAs) with high packing density on the wafer scale. By means of conformal chemical vapor deposition (CVD) of hydrogenated amorphous silicon (a-Si:H) following patterning of silicon pillars via electron beam lithography (EBL) and plasma etching, large areas of a close packed silicon lens array with the diameter from a few micrometers down to a few hundred nanometers was fabricated. The resulting structure shows excellent surface roughness and high uniformity. The optical focusing properties of the lenses at infrared wavelengths were verified by experimental measurements and numerical simulation. This approach provides a feasible solution for fabricating silicon MNLAs compatible for next generation large scale, miniaturized optical imaging detectors and related optical devices.
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27
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Yang Q, Li BQ, Tian H, Li X, Shao J, Chen X, Xu F. Deformation Hysteresis of Electrohydrodynamic Patterning on a Thin Polymer Film. ACS APPLIED MATERIALS & INTERFACES 2016; 8:17668-17675. [PMID: 27326791 DOI: 10.1021/acsami.6b04192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electrohydrodynamic patterning is a technique that enables micro/nanostructures via imposing an external voltage on thin polymer films. In this investigation, we studied the electrohydrodynamic patterning theoretically and experimentally, with special interest focused on the equilibrium state. It is found that the equilibrium structure height increases with the voltage. In addition, we have observed, and believe it to be the first time, a hysteresis phenomenon exists in the relationship between the voltage and structure height. With an increase in the voltage, a critical value (the first critical voltage) is noticed, above which the polymer film would increase dramatically until it comes into contact with the template. However, with a decrease in the voltage, a smaller voltage (the second critical voltage) is needed to detach the polymer from the template. The mismatch of the first and second critical voltages distorts the voltage-structure height curve into an "S" shape. Such a phenomenon is verified for three representative templates and also by experiments. Furthermore, the effects of some parameters (e.g., polymer film thickness and dielectric constant) on this hysteresis phenomenon are also discussed.
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Affiliation(s)
| | - Ben Q Li
- Department of Mechanical Engineering, University of Michigan-Dearborn , Dearborn, Michigan 48128, United States
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28
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Roy AC, Yadav M, Arul EP, Khanna A, Ghatak A. Generation of Aspherical Optical Lenses via Arrested Spreading and Pinching of a Cross-Linkable Liquid. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5356-5364. [PMID: 27200461 DOI: 10.1021/acs.langmuir.5b04631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Aspherical optical lenses with spatially varying curvature are desired for capturing high quality, aberration free images in numerous optical applications. Conventionally such lenses are prepared by multistep top-down processes which are expensive, time-consuming, and prone to high failure rate. In this context, an alternate method is presented here based on arrested spreading of a sessile drop of a transparent, cross-linkable polymeric liquid on a solid substrate heated to an elevated temperature. Whereas surface tension driven flow tends to render it spherical, rapid cross-linking arrests such flow so that nonequilibrium aspherical shapes are attained. It is possible to tune also the initial state of the drop via delayed pinching of a liquid cylinder which precedes its release on the substrate. This method has led to the generation of a wide variety of optical lenses, ranging from spherical plano convex to superspherical solid immersion to exotic lenses not achieved via conventional methods.
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Affiliation(s)
| | | | - Edward Peter Arul
- Central Electrochemical Research Institute, CECRI (CSIR) , Karaikudi, Sivaganga-630006, Tamil Nadu India
| | - Anubhav Khanna
- Department of Chemical Engineering, Manipal Institute of Technology , Manipal, 576104, Karnataka India
| | - Animangsu Ghatak
- INM-Leibniz Institute for New Materials and Saarland University , Campus D 2 2, 66123 Saarbrucken, Germany
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29
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Yang Y, Huang X, Zhang X, Jiang F, Zhang X, Wang Y. Supercritical Fluid-Driven Polymer Phase Separation for Microlens with Tunable Dimension and Curvature. ACS APPLIED MATERIALS & INTERFACES 2016; 8:8849-58. [PMID: 26999714 DOI: 10.1021/acsami.6b01951] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Microlenses are highly sought as reliable means for high-resolution optical imaging at low illumination intensities. Plano-convex configuration with tunable dimension and curvature is an essential feature in the microlens fabrication. In this study, we present a facile and green route for preparing well-defined microlenses based on polymer phase separation in the presence of supercritical carbon dioxide (scCO2). The behaviors of linear polymethylmethacrylate protruded from cross-linked silicone network in scCO2 environment are investigated from the perspectives of thermodynamics and kinetics. Microlenses with dimensions from 2 to 15 μm and contact angles from 55° to 112° are successfully obtained through the adjustment of the kinetic conditions and outgassing rate. With the tunable focal length, they exhibit intrinsic function of discerning submicroscale patterns that are unable to be observed directly under optical microscope. Moreover, size confinement on the substrate results in the generation of well-ordered microlens arrays, affording great promise for applications in bioimaging, photolithography, light harvesting, and optical nanosensing.
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Affiliation(s)
- Youdi Yang
- Department of Chemistry, Renmin University of China , Beijing 100872, China
| | - Xiaopeng Huang
- Department of Chemistry, Renmin University of China , Beijing 100872, China
| | - Xinyue Zhang
- Department of Chemistry, Renmin University of China , Beijing 100872, China
| | - Fuze Jiang
- Department of Chemistry, Renmin University of China , Beijing 100872, China
| | - Xiaogang Zhang
- Department of Chemistry, Renmin University of China , Beijing 100872, China
| | - Yapei Wang
- Department of Chemistry, Renmin University of China , Beijing 100872, China
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30
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Lv G, Zhang S, Shao J, Tian H, Wang G, Yu D. Preparation, properties, and efficient electrically induced structure formation of a leaky dielectric photoresist. RSC Adv 2016. [DOI: 10.1039/c6ra17957f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Electrohydrodynamic structures with hydrophobic surfaces were fabricated instantaneously at ambient temperature using a designed leaky dielectric photoresist film.
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Affiliation(s)
- Guowei Lv
- Department of Chemistry
- School of Science
- State Key Laboratory of Electrical Insulation and Power Equipments
- Xi'an Jiaotong University
- Xi'an 710049
| | - Shihu Zhang
- Department of Chemistry
- School of Science
- State Key Laboratory of Electrical Insulation and Power Equipments
- Xi'an Jiaotong University
- Xi'an 710049
| | - Jinyou Shao
- State Key Laboratory of Manufacturing Systems Engineering
- Xi'an Jiaotong University
- Xi'an 710049
- P. R. China
| | - Hongmiao Tian
- State Key Laboratory of Manufacturing Systems Engineering
- Xi'an Jiaotong University
- Xi'an 710049
- P. R. China
| | - Guolong Wang
- Department of Chemistry
- School of Science
- State Key Laboratory of Electrical Insulation and Power Equipments
- Xi'an Jiaotong University
- Xi'an 710049
| | - Demei Yu
- Department of Chemistry
- School of Science
- State Key Laboratory of Electrical Insulation and Power Equipments
- Xi'an Jiaotong University
- Xi'an 710049
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31
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Chrimes AF, Khodasevych I, Mitchell A, Rosengarten G, Kalantar-zadeh K. Dielectrophoretically controlled Fresnel zone plate. LAB ON A CHIP 2015; 15:1092-1100. [PMID: 25524620 DOI: 10.1039/c4lc01213e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Switchability is a highly sought after feature for planar optical systems. Suspensions of nanomaterials can be used for generating controllable changes in such systems. We report a planar diffractive microfluidic lens which integrates controlled dielectrophoresis (DEP) for trapping suspended nanomaterials. Silicon and tungsten oxide nanoparticle suspensions are used. These nanomaterials are trapped in such a way as to form alternating opaque and transparent rings using the DEP forces on demand. These rings form a planar diffractive Fresnel zone plate to focus the incident light. The Fresnel zone plate is tuned for the visible light region and the lens can be turned on (DEP applied) or off (DEP removed) in a controlled manner. This proof of concept demonstration can be further expanded for a variety of switchable optical devices and can be integrated with lab-on-a-chip and optofluidic devices.
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Affiliation(s)
- A F Chrimes
- School of Electrical and Computer Engineering, RMIT University, Melbourne, Australia.
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32
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Jiang C, Li X, Tian H, Wang C, Shao J, Ding Y, Wang L. Lateral flow through a parallel gap driven by surface hydrophilicity and liquid edge pinning for creating microlens array. ACS APPLIED MATERIALS & INTERFACES 2014; 6:18450-18456. [PMID: 25348103 DOI: 10.1021/am506067v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This letter proposes a surface-energy driven process for economically creating polymer microlens array (MLA) with well controllable curvatures. When a UV-curable prepolymer flows into a cell constructed by multiple holes on a top template and a flat substrate, since the edge pinning of the contact line, an array of curved air/prepolymer interface forms around each microhole of the template. Then a UV-radiation of the bulk prepolymer leads to a solid microlens array. The curvature of the air/prepolymer interface can be controlled by choosing materials with different interface free energy or varying the gap height mechanically.
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Affiliation(s)
- Chengbao Jiang
- Micro-/Nano-technology Research Center State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University , 28 West Xianning Road, Xi'an, Shaanxi 710049, China
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33
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Tian H, Wang C, Shao J, Ding Y, Li X. Electrohydrodynamic pressure enhanced by free space charge for electrically induced structure formation with high aspect ratio. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:12654-12663. [PMID: 25268463 DOI: 10.1021/la5027043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Electrically induced structure formation (EISF) is an interesting and unique approach for generating a microstructured duplicate from a rheological polymer by a spatially modulated electric field induced by a patterned template. Most of the research on EISF have so far used various dielectric polymers (with an electrical conductivity smaller than 10(-10) S/m that can be considered a perfect dielectric), on which the electric field induces a Maxwell stress only due to the dipoles (or bounded charges) in the polymer molecules, leading to a structure with a small aspect ratio. This paper presents a different approach for improving the aspect ratio allowed in EISF by doping organic salt into the perfect dielectric polymer, i.e., turning the perfect dielectric into a leaky dielectric, considering the fact that the free space charges enriched in the leaky dielectric polymer can make an additional contribution to the Maxwell stress, i.e., electrohydrodynamic pressure, which is desirable for high aspect ratio structuring. Our numerical simulations and experimental tests have shown that a leaky dielectric polymer, with a small conductivity comparable to that of deionized water, can be much more effective at being electrohydrodynamically deformed into a high aspect ratio in comparison with a perfect dielectric polymer when both of them have roughly the same dielectric constant.
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Affiliation(s)
- Hongmiao Tian
- Micro- and Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, China
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34
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Yang Q, Li BQ, Ding Y, Shao J. Steady State of Electrohydrodynamic Patterning of Micro/Nanostructures on Thin Polymer Films. Ind Eng Chem Res 2014. [DOI: 10.1021/ie502288a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Qingzhen Yang
- State
Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, People’s Republic of China
| | - Ben Q. Li
- Department
of Mechanical Engineering, University of Michigan, Dearborn, Michigan 48128, United States
| | - Yucheng Ding
- State
Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, People’s Republic of China
| | - Jinyou Shao
- State
Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, People’s Republic of China
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35
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Tian H, Shao J, Ding Y, Li X, Liu H. Simulation of polymer rheology in an electrically induced micro- or nano-structuring process based on electrohydrodynamics and conservative level set method. RSC Adv 2014. [DOI: 10.1039/c4ra00553h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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36
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Yang Q, Li BQ, Ding Y. Dynamic modelling of micro/nano-patterning transfer by an electric field. RSC Adv 2013. [DOI: 10.1039/c3ra44747b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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