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Yong Y, Chen S, Chen H, Ge H, Hao Z. A Rapid Fabrication Method of Large-Area MLAs with Variable Curvature for Retroreflectors Based on Thermal Reflow. MICROMACHINES 2024; 15:816. [PMID: 39064327 PMCID: PMC11278960 DOI: 10.3390/mi15070816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/31/2024] [Accepted: 06/14/2024] [Indexed: 07/28/2024]
Abstract
Retroreflectors are an important optical component, but current retroreflector structures and manufacturing processes are relatively complex. This paper proposes a rapid, low-cost, large-area method for fabricating retroreflectors based on microlens arrays. Tunable microlens arrays with adjustable curvature, fill factor, and sizes were prepared using photolithography and thermal reflow techniques. Subsequently, a two-step nanoimprinting process was used to create a flexible reverse mold and transfer the structure onto the desired substrate. The microlens arrays, with a diameter of 30 μm, a period of 33 μm, a curvature radius ranging from 15.5 to 18.8 μm, and a fill factor ranging from 75.1% to 88.8%, were fabricated this way. In addition, the method also fabricated microlens arrays with diameters ranging from 10 to 80 μm. Retroreflectors were made by sputtering a layer of silver on the MLAs as a reflecting layer, and tests showed that the microlens-based retroreflector exhibited superior retroreflective performance with a wide-angle response of ±75°. Microlens-based retroreflectors have the advantages of simple operation and controllable profiles. The fabrication method in this paper is suitable for large-scale production, providing a new approach to retroreflector design.
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Affiliation(s)
- Yiqiu Yong
- Department of Materials Science and Engineering, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; (Y.Y.); (S.C.); (H.G.)
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China;
| | - Si Chen
- Department of Materials Science and Engineering, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; (Y.Y.); (S.C.); (H.G.)
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China;
| | - Hao Chen
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China;
- School of Physics, Nanjing University, Nanjing 210093, China
| | - Haixiong Ge
- Department of Materials Science and Engineering, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; (Y.Y.); (S.C.); (H.G.)
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China;
| | - Zongbin Hao
- Department of Materials Science and Engineering, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; (Y.Y.); (S.C.); (H.G.)
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China;
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2
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Wu Y, Dong X, Wang X, Xiao J, Sun Q, Shen L, Lan J, Shen Z, Xu J, Du Y. Fabrication of Large-Area Silicon Spherical Microlens Arrays by Thermal Reflow and ICP Etching. MICROMACHINES 2024; 15:460. [PMID: 38675271 PMCID: PMC11052383 DOI: 10.3390/mi15040460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024]
Abstract
In this paper, we proposed an efficient and high-precision process for fabricating large-area microlens arrays using thermal reflow combined with ICP etching. When the temperature rises above the glass transition temperature, the polymer cylinder will reflow into a smooth hemisphere due to the surface tension effect. The dimensional differences generated after reflow can be corrected using etching selectivity in the following ICP etching process, which transfers the microstructure on the photoresist to the substrate. The volume variation before and after reflow, as well as the effect of etching selectivity using process parameters, such as RF power and gas flow, were explored. Due to the surface tension effect and the simultaneous molding of all microlens units, machining a 3.84 × 3.84 mm2 silicon microlens array required only 3 min of reflow and 15 min of ICP etching with an extremely low average surface roughness Sa of 1.2 nm.
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Affiliation(s)
- Yu Wu
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
| | - Xianshan Dong
- Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory, Guangzhou 511370, China;
| | - Xuefang Wang
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
| | - Junfeng Xiao
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
| | - Quanquan Sun
- Shanghai Aerospace Control Technology Institute, Shanghai 201109, China (L.S.); (J.L.); (Z.S.)
| | - Lifeng Shen
- Shanghai Aerospace Control Technology Institute, Shanghai 201109, China (L.S.); (J.L.); (Z.S.)
| | - Jie Lan
- Shanghai Aerospace Control Technology Institute, Shanghai 201109, China (L.S.); (J.L.); (Z.S.)
| | - Zhenfeng Shen
- Shanghai Aerospace Control Technology Institute, Shanghai 201109, China (L.S.); (J.L.); (Z.S.)
| | - Jianfeng Xu
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
| | - Yuqingyun Du
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
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3
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Sun ZJ, Liu YQ, Wan JY, Liu XQ, Han DD, Chen QD, Zhang YL. Reconfigurable Microlens Array Enables Tunable Imaging Based on Shape Memory Polymers. ACS APPLIED MATERIALS & INTERFACES 2024; 16:9581-9592. [PMID: 38332526 DOI: 10.1021/acsami.4c01030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Microlens arrays (MLAs) with a tunable imaging ability are core components of advanced micro-optical systems. Nevertheless, tunable MLAs generally suffer from high power consumption, an undeformable rigid body, large and complex systems, or limited focal length tunability. The combination of reconfigurable smart materials with MLAs may lead to distinct advantages including programmable deformation, remote manipulation, and multimodal tunability. However, unlike photopolymers that permit flexible structuring, the fabrication of tunable MLAs and compound eyes (CEs) based on transparent smart materials is still rare. In this work, we report reconfigurable MLAs that enable tunable imaging based on shape memory polymers (SMPs). The smart MLAs with closely packed 200 × 200 microlenses (40.0 μm in size) are fabricated via a combined technology that involves wet etching-assisted femtosecond laser direct writing of MLA templates on quartz, soft lithography for MLA duplication using SMPs, and the mechanical heat setting for programmable reconfiguration. By stretching or squeezing the shape memory MLAs at the transition temperature (80 °C), the size, profiles, and spatial distributions of the microlenses can be programmed. When the MLA is stretched from 0 to 120% (area ratio), the focal length is increased from 116 to 283 μm. As a proof of concept, reconfigurable MLAs and a 3D CE with a tunable field of view (FOV, 160-0°) have been demonstrated in which the thermally triggered shape memory deformation has been employed for tunable imaging. The reconfigurable MLAs and CEs with a tunable focal length and adjustable FOV may hold great promise for developing smart micro-optical systems.
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Affiliation(s)
- Zhi-Juan Sun
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Yu-Qing Liu
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory for UV Emitting Materials and Technology of Ministry of Education, National Demonstration Center for Experimental Physics Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Jia-Yi Wan
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Xue-Qing Liu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Dong-Dong Han
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Qi-Dai Chen
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Yong-Lai Zhang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
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Peng F, Sun C, Wan H, Gui C. An Improved 3D OPC Method for the Fabrication of High-Fidelity Micro Fresnel Lenses. MICROMACHINES 2023; 14:2220. [PMID: 38138389 PMCID: PMC10745535 DOI: 10.3390/mi14122220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/03/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023]
Abstract
Based on three-dimensional optical proximity correction (3D OPC), recent advancements in 3D lithography have enabled the high-fidelity customization of 3D micro-optical elements. However, the micron-to-millimeter-scale structures represented by the Fresnel lens design bring more stringent requirements for 3D OPC, which poses significant challenges to the accuracy of models and the efficiency of algorithms. Thus, a lithographic model based on optical imaging and photochemical reaction curves is developed in this paper, and a subdomain division method with a statistics principle is proposed to improve the efficiency and accuracy of 3D OPC. Both the simulation and the experimental results show the superiority of the proposed 3D OPC method in the fabrication of Fresnel lenses. The computation memory requirements of the 3D OPC are reduced to below 1%, and the profile error of the fabricated Fresnel lens is reduced 79.98%. Applying the Fresnel lenses to an imaging system, the average peak signal to noise ratio (PSNR) of the image is increased by 18.92%, and the average contrast of the image is enhanced by 36%. We believe that the proposed 3D OPC method can be extended to the fabrication of vision-correcting ophthalmological lenses.
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Affiliation(s)
- Fei Peng
- Institute of Technological Sciences, Wuhan University, Wuhan 430072, China; (F.P.); (C.S.); (H.W.)
- Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration, Wuhan University, Wuhan 430072, China
| | - Chao Sun
- Institute of Technological Sciences, Wuhan University, Wuhan 430072, China; (F.P.); (C.S.); (H.W.)
- Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration, Wuhan University, Wuhan 430072, China
| | - Hui Wan
- Institute of Technological Sciences, Wuhan University, Wuhan 430072, China; (F.P.); (C.S.); (H.W.)
- Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration, Wuhan University, Wuhan 430072, China
| | - Chengqun Gui
- Institute of Technological Sciences, Wuhan University, Wuhan 430072, China; (F.P.); (C.S.); (H.W.)
- Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration, Wuhan University, Wuhan 430072, China
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5
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Liu Y, Huang J, Yin B, Ye Y, Liang M, Chen X, Wang F, Zhang J, Dai Z. Femtosecond laser printing-assisted etching tailored hard and brittle micro-convex surface. OPTICS LETTERS 2023; 48:5097-5100. [PMID: 37773394 DOI: 10.1364/ol.501146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 09/05/2023] [Indexed: 10/01/2023]
Abstract
We report a femtosecond laser print-assisted dry etching technology for high-efficiency, high-quality, and tailored fabricating of a micro-convex surface (MCS) on hard and brittle materials. Liquid ultraviolet curing adhesive (UVCA) was transferred from a donor substrate to a receiving substrate by femtosecond laser-induced forward transfer, and the transferred microdroplet spontaneously has a smooth surface under the action of surface tension. And then an MCS with a high-quality surface was formed on hard and brittle materials by UV curing and dry etching. The effects of laser parameters and receiving substrate surface free energy on MCS morphology were investigated. According to the variation of the numerical aperture, the two methods to change the morphology of the MCS were divided into independent/joint regulation of diameter and height. We showed that a hexagonal array containing a variety of MCS morphologies can be fabricated on a fused silica by setting the appropriate parameters. And the fabrication time of an MCS in a large-area array was only 1.1 s.
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6
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Liu Z, Hu G, Ye H, Wei M, Guo Z, Chen K, Liu C, Tang B, Zhou G. Mold-free self-assembled scalable microlens arrays with ultrasmooth surface and record-high resolution. LIGHT, SCIENCE & APPLICATIONS 2023; 12:143. [PMID: 37286533 DOI: 10.1038/s41377-023-01174-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 04/11/2023] [Accepted: 04/26/2023] [Indexed: 06/09/2023]
Abstract
Microlens arrays (MLAs) based on the selective wetting have opened new avenues for developing compact and miniaturized imaging and display techniques with ultrahigh resolution beyond the traditional bulky and volumetric optics. However, the selective wetting lenses explored so far have been constrained by the lack of precisely defined pattern for highly controllable wettability contrast, thus limiting the available droplet curvature and numerical aperture, which is a major challenge towards the practical high-performance MLAs. Here we report a mold-free and self-assembly approach of mass-production of scalable MLAs, which can also have ultrasmooth surface, ultrahigh resolution, and the large tuning range of the curvatures. The selective surface modification based on tunable oxygen plasma can facilitate the precise pattern with adjusted chemical contrast, thus creating large-scale microdroplets array with controlled curvature. The numerical aperture of the MLAs can be up to 0.26 and precisely tuned by adjusting the modification intensity or the droplet dose. The fabricated MLAs have high-quality surface with subnanometer roughness and allow for record-high resolution imaging up to equivalently 10,328 ppi, as we demonstrated. This study shows a cost-effective roadmap for mass-production of high-performance MLAs, which may find applications in the rapid proliferating integral imaging industry and high-resolution display.
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Affiliation(s)
- Zhihao Liu
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Guangwei Hu
- School of Electrical and Electronic Engineering, 50 Nanyang Avenue, Nanyang Technological University, Singapore, 639798, Singapore
| | - Huapeng Ye
- 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, China.
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China.
| | - Miaoyang Wei
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Zhenghao Guo
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Kexu Chen
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Chen Liu
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, 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, China.
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China.
| | - 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, China.
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China.
- Shenzhen Guohua Optoelectronics Tech. Co. Ltd, Shenzhen, 518110, China.
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Luan S, Cao H, Deng H, Zheng G, Song Y, Gui C. Artificial Hyper Compound Eyes Enable Variable-Focus Imaging on both Curved and Flat Surfaces. ACS APPLIED MATERIALS & INTERFACES 2022; 14:46112-46121. [PMID: 36174005 DOI: 10.1021/acsami.2c15489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The artificial compound eye (ACE) with zoom imaging requires complex power sources. Meanwhile, its curved substrate makes it difficult for the ACE to realize the zoom imaging on flat surfaces. To realize a wide field of view and a zoom function on both curved and flat surfaces simultaneously, a novel ACE is proposed, which is a bionic design inspired by an ancient creature, trilobite. Compared with a dragonfly, photosensitive units of a trilobite's compound eye are composed of ommatidia with different focal lengths. By learning from this concept, an artificial hyper compound eye (AHCE) was fabricated. Its basic components are five microlenses with different curvatures, and they are capable of being treated as five ommatidia with different focal lengths. Five ommatidia form a photosensitive unit to realize a zoom function. AHCE is capable of variable-focus imaging on curved surfaces. With the information share function, we found that the AHCE not only images on curved surfaces but also has a zoom-imaging function on flat surfaces. The results confirm that the AHCE demonstrates an advanced imaging capability, a variable-focus imaging function on both curved and flat surfaces, which may open new opportunities in developing advanced micro-optical devices.
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Affiliation(s)
- Shiyi Luan
- School of Power and Mechanical Engineering, Wuhan University, Wuhan430072, China
| | - Hao Cao
- The Institute of Technological Sciences, Wuhan University, Wuhan430072, China
| | - Hongfeng Deng
- The Institute of Technological Sciences, Wuhan University, Wuhan430072, China
| | - Guoxing Zheng
- Electronic Information School, Wuhan University, Wuhan430072, China
| | - Yi Song
- The Institute of Technological Sciences, Wuhan University, Wuhan430072, China
| | - Chengqun Gui
- The Institute of Technological Sciences, Wuhan University, Wuhan430072, China
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8
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Gao X, Hu X, Zheng J, Hu Q, Zhao S, Chen L, Yang Y. On-demand liquid microlens arrays by non-contact relocation of inhomogeneous fluids in acoustic fields. LAB ON A CHIP 2022; 22:3942-3951. [PMID: 36102930 DOI: 10.1039/d2lc00603k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Microlens arrays (MLAs) are key micro-optical components that possess a high degree of parallelism and ease of integration. However, rapid and low-cost fabrication of MLAs with flexible focusing remains a challenge. Herein, liquid MLAs with dynamic tunability are presented using non-contact acoustic relocation of inhomogeneous fluids. By designing ring-shaped acoustic pressure node (PN) arrays, the denser fluid of miscible liquids is relocated to PNs, and liquid MLAs with ideal morphology are obtained. The experimental results demonstrate that the liquid MLAs possess a powerful reconfigurability with long-term stability and sharp imaging that can conveniently switch between the on and off state and can dynamically magnify by simply adjusting the acoustic amplitude. Moreover, the high biocompatibility inherited from liquids accompanied by the acoustic treatment allows cells to be within working distance of the MLAs without immersion, as would be required for a solid lens. This innovative liquid MLA is inexpensive to manufacture and possesses continuous focus, fast response, and satisfactory bioaffinity, and thus offers promising potential for microfluidic adaptive imaging and biomedical sensing, especially for live cell imaging.
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Affiliation(s)
- Xiaoqi Gao
- School of Physics & Technology, Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, Wuhan University, Wuhan 430072, China.
- Shenzhen Research Institute, Wuhan University, Shenzhen 518000, China
| | - Xuejia Hu
- Department of Electronic Engineering, School of Electronic Science and Engineering, Xiamen University, Xiamen 361005, China
| | - Jingjing Zheng
- School of Physics & Technology, Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, Wuhan University, Wuhan 430072, China.
- Shenzhen Research Institute, Wuhan University, Shenzhen 518000, China
| | - Qinghao Hu
- School of Physics & Technology, Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, Wuhan University, Wuhan 430072, China.
- Shenzhen Research Institute, Wuhan University, Shenzhen 518000, China
| | - Shukun Zhao
- School of Physics & Technology, Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, Wuhan University, Wuhan 430072, China.
- Shenzhen Research Institute, Wuhan University, Shenzhen 518000, China
| | - Longfei Chen
- School of Physics & Technology, Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, Wuhan University, Wuhan 430072, China.
- Shenzhen Research Institute, Wuhan University, Shenzhen 518000, China
| | - Yi Yang
- School of Physics & Technology, Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, Wuhan University, Wuhan 430072, China.
- Shenzhen Research Institute, Wuhan University, Shenzhen 518000, China
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9
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Yang T, Li M, Yang Q, Lu Y, Cheng Y, Zhang C, Du B, Hou X, Chen F. Femtosecond Laser Fabrication of Submillimeter Microlens Arrays with Tunable Numerical Apertures. MICROMACHINES 2022; 13:mi13081297. [PMID: 36014220 PMCID: PMC9414556 DOI: 10.3390/mi13081297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/17/2022] [Accepted: 08/04/2022] [Indexed: 06/12/2023]
Abstract
In recent years, the demand for optical components such as microlenses has been increasing, and various methods have been developed. However, fabrication of submillimeter microlenses with tunable numerical aperture (NA) on hard and brittle materials remains a great challenge using the current methods. In this work, we fabricated a variable NA microlens array with submillimeter size on a silica substrate, using a femtosecond laser-based linear scanning-assisted wet etching method. At the same time, the influence of various processing parameters on the microlens morphology and NA was studied. The NA of the microlenses could be flexibly adjusted in the range of 0.2 to 0.45 by changing the scanning distance of the laser and assisted wet etching. In addition, the imaging and focusing performance tests demonstrated the good optical performance and controllability of the fabricated microlenses. Finally, the optical performance simulation of the prepared microlens array was carried out. The result was consistent with the actual situation, indicating the potential of the submillimeter-scale microlens array prepared by this method for applications in imaging and detection.
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Affiliation(s)
- Tongzhen Yang
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Minjing Li
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Qing Yang
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Yu Lu
- State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Yang Cheng
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Chengjun Zhang
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Bing Du
- State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Xun Hou
- State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Feng Chen
- State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
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Zhang Z, Chu F, Wang X, Zhou X, Xiong G. Microfluidic Fabrication of a PDMS Microlens for Imaging Tunability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4059-4064. [PMID: 35324201 DOI: 10.1021/acs.langmuir.2c00079] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A microfluidic system was created to fabricate polydimethylsiloxane (PDMS) microspheres, whose shape, surface smoothness, and size were controlled. Resulting from their excellent optical properties and elasticity prepared by the apparatus, each PDMS microsphere could act as a microlens and separate imaging unit. The focal length of the microlens was simply tuned by the forces posed on the beads. For the microlens array (MLA) application, it was constructed simply through the assembly of the monodisperse PDMS beads.
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Affiliation(s)
- Zhiguang Zhang
- Key Laboratory of Green Printing & Packaging Materials and Technology in Universities of Shandong, Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, China
| | - Fuqiang Chu
- Key Laboratory of Green Printing & Packaging Materials and Technology in Universities of Shandong, Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, China
| | - Xin Wang
- School of Mechanical and Precision Instrument Engineering, Xi'an University of Technology, Xi'an 710048, Shanxi, China
| | - Xu Zhou
- Key Laboratory of Green Printing & Packaging Materials and Technology in Universities of Shandong, Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, China
| | - Guirong Xiong
- Key Laboratory of Green Printing & Packaging Materials and Technology in Universities of Shandong, Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, China
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11
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Wang BX, Zheng JX, Qi JY, Guo MR, Gao BR, Liu XQ. Integration of Multifocal Microlens Array on Silicon Microcantilever via Femtosecond-Laser-Assisted Etching Technology. MICROMACHINES 2022; 13:mi13020218. [PMID: 35208341 PMCID: PMC8878309 DOI: 10.3390/mi13020218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 11/16/2022]
Abstract
Micro-opto-electromechanical systems (MOEMSs) are a new class of integrated and miniaturized optical systems that have significant applications in modern optics. However, the integration of micro-optical elements with complex morphologies on existing micro-electromechanical systems is difficult. Herein, we propose a femtosecond-laser-assisted dry etching technology to realize the fabrication of silicon microlenses. The size of the microlens can be controlled by the femtosecond laser pulse energy and the number of pulses. To verify the applicability of this method, multifocal microlens arrays (focal lengths of 7–9 μm) were integrated into a silicon microcantilever using this method. The proposed technology would broaden the application scope of MOEMSs in three-dimensional imaging systems.
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12
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Majumder A, Meem M, Stewart R, Menon R. Broadband point-spread function engineering via a freeform diffractive microlens array. OPTICS EXPRESS 2022; 30:1967-1975. [PMID: 35209347 DOI: 10.1364/oe.443338] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
We utilized inverse design to engineer the point-spread function (PSF) of a low-f-number, freeform diffractive microlens in an array, so as to enable extended depth of focus (DOF). Each square microlens of side 69 µm and focal length 40 µm (in a polymer film, n∼1.47) generated a square PSF of side ∼10 µm that was achromatic over the visible band (450 to 750 nm), and also exhibited an extended DOF of ∼ ± 2 µm. The microlens has a geometric f/# (focal length divided by aperture size) of 0.58 in the polymer material (0.39 in air). Since each microlens is a square, the microlens array (MLA) can achieve 100% fill factor. By placing this microlens array (MLA) directly on a high-resolution print, we demonstrated integral imaging with applications in physical security. The extended DOF preserves the optical effects even with expected film-thickness variations, thereby increasing robustness in practical applications. Since these multi-level diffractive MLAs are fabricated using UV-nanoimprint lithography, they have the potential for low-cost large volume manufacturing.
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13
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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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14
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Kim S, Handler JJ, Cho YT, Barbastathis G, Fang NX. Scalable 3D printing of aperiodic cellular structures by rotational stacking of integral image formation. SCIENCE ADVANCES 2021; 7:eabh1200. [PMID: 34533994 PMCID: PMC8448457 DOI: 10.1126/sciadv.abh1200] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The limitation of projection microstereolithography in additive manufacturing methods is that they typically use a single-aperture imaging configuration, which restricts their ability to produce microstructures in large volumes owing to the trade-off between image resolution and image field area. Here, we propose an integral lithography based on integral image reconstruction coupled with a planar lens array. The individual microlenses maintain a high numerical aperture and are used to create digital light patterns that can expand the printable area by the number of microlenses (103 to 104), thereby allowing for the scalable stereolithographic fabrication of 3D features that surpass the resolution-to-area scaling limit. We extend the capability of integral lithography for programmable printing of deterministic nonperiodic structures through the rotational overlapping or stacking of multiple exposures with controlled angular offsets. This printing platform provides new possibilities for producing periodic and aperiodic microarchitectures spanning four orders of magnitude from micrometers to centimeters.
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Affiliation(s)
- Seok Kim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Mechanical Engineering, Changwon National University, Changwon, South Korea
| | - Jordan J. Handler
- Sloan School of Management, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Young Tae Cho
- Department of Mechanical Engineering, Changwon National University, Changwon, South Korea
| | - George Barbastathis
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Singapore-MIT Alliance for Research and Technology (SMART) Centre, 1 Create Way, Singapore 138602, Singapore
| | - Nicholas X. Fang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Corresponding author.
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15
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Yuan W, Cai Y, Xu C, Pang H, Cao A, Fu Y, Deng Q. Fabrication of Multifocal Microlens Array by One Step Exposure Process. MICROMACHINES 2021; 12:mi12091097. [PMID: 34577740 PMCID: PMC8469672 DOI: 10.3390/mi12091097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 01/26/2023]
Abstract
Microlenses can be widely used in integrated micro-optical systems. However, in some special applications, such as light field imaging systems, multifocal microlens arrays (MLA) are expected to improve imaging resolution. For the fabrication of multifocal MLA, the traditional fabrication method is no longer applicable. To solve this problem, a fabrication method of multifocal MLA by a one step exposure process is proposed. Through the analyses and research of photoresist AZ9260, the nonlinear relationship between exposure dose and exposure depth is established. In the design of the mask, the mask pattern is corrected according to the nonlinear relationship to obtain the final mask. The continuous surface of the multifocal MLA is fabricated by the mask moving exposure. The experimental results show that the prepared multifocal MLA has high filling factor and surface fidelity. What is more, this method is simple and efficient to use in practical applications.
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Affiliation(s)
- Wei Yuan
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.)
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Yajuan Cai
- School of Information Science and Technology, Southwest Jiao Tong University, Chengdu 610031, China;
| | - Cheng Xu
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.)
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Hui Pang
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Axiu Cao
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
- Correspondence: (A.C.); (Y.F.); Tel.: +86-028-8510-1178 (A.C.); +86-1520-834-0157 (Y.F.)
| | - Yongqi Fu
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.)
- Correspondence: (A.C.); (Y.F.); Tel.: +86-028-8510-1178 (A.C.); +86-1520-834-0157 (Y.F.)
| | - Qiling Deng
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
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16
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Yuan D, Liu B, Guo Y, Zhu Z, Liu M, Cheng C, Gu M, Zhou S, Xu Q, Chen L, Liu J, Ouyang X. Light output enhancement of scintillators by using mixed-scale microstructures. OPTICS EXPRESS 2021; 29:24792-24803. [PMID: 34614827 DOI: 10.1364/oe.432114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/10/2021] [Indexed: 06/13/2023]
Abstract
Scintillators play an important role in the field of nuclear radiation detection. However, the light output of the scintillators is often limited by total internal reflection due to the high refractive indices of the scintillators. Furthermore, the light emission from scintillators typically has an approximately Lambertian profile, which is detrimental to the collection of the light. In this paper, we demonstrate a promising method to achieve enhancement of the light output from scintillators through use of mixed-scale microstructures that are composed of a photonic crystal slab and a microlens array. Simulations and experimental results both show significant improvements in the scintillator light output. The X-ray imaging characteristics of scintillators are improved by the application of the mixed-scale microstructures. The results presented here suggest that the application of the proposed mixed-scale microstructures to scintillators will be beneficial in the nuclear radiation detection field.
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17
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Lee S, Yoo C, Yoon H, Kim D, Kim G, Lee B, Hong Y. 3D printing-based mirrored image component for seamless modular curved-edge displays. OPTICS EXPRESS 2021; 29:14745-14756. [PMID: 33985190 DOI: 10.1364/oe.423598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
A facile method for designing and fabricating a concave mirror from a 3D printed mold is proposed for a seamless modular curved-edge display. The concave mirror is placed on the seam of modular curved-edge display, thereby reflecting images at the curved-edge area toward the observer direction. By investigating the concave mirror structures based on parametric modeling, we obtain a continuous image in a modular curved-edge display by optically concealing the seam. We also analyze the luminance distribution and the viewing angle of the seamless modular curved-edge display to show the capability of concealing the seam by the concave mirror.
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18
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Long Y, Song Z, Pan M, Tao C, Hong R, Dai B, Zhang D. Fabrication of uniform-aperture multi-focus microlens array by curving microfluid in the microholes with inclined walls. OPTICS EXPRESS 2021; 29:12763-12771. [PMID: 33985026 DOI: 10.1364/oe.425333] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
A variety of techniques have been proposed for fabricating high-density, high-numerical-aperture microlens arrays. However, a microlens array with a uniform focal length has a narrow depth of field, limiting the ability of depth perception. In this paper, we report on a fabrication method of multi-focus microlens arrays. The method for the preparation of the mold of the microlens array is based on 3D printing and microfluidic manipulation techniques. In the preparation of the mold, curved surfaces of the photo-curable resin with different curvatures are formed in the 3D printed microholes whose walls are inclined with different angles. The replicated microlens array consists of hundreds of lenslets with a uniform diameter of 500 µm and different focal lengths ranging from 635 µm to 970 µm. The multi-focus microlens array is capable of extending the depth of field for capturing clear images of objects at different distances ranging from 14.3 mm to 45.5 mm. The multi-focus microlens array has the potential to be used in a diversity of large-depth-of-field imaging and large-range depth perception applications.
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19
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Peng Y, Zhou X, Zhang Y, Guo T. Fabrication of a micro-lens array for improving depth-of-field of integral imaging 3D display. APPLIED OPTICS 2020; 59:9104-9107. [PMID: 33104619 DOI: 10.1364/ao.402704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
In this paper, we present a new, to the best of our knowledge, structure of double pinhole/micro-lens array (DP/MLA) with two center-depth planes, used for improving the depth-of-field (DOF) of integral imaging (II), which can be fabricated by a combination of lithography and inkjet printing. The results show that a black circular groove array prepared by lithography can be used for micro-lens location and reduce the stray light for II. By controlling the parameters of the inkjet printing system, DP/MLA with high precision, high alignment, and good focusing ability can be achieved. When the fabricated DP/MLA is applied in the II system, the reconstructed image has a better three-dimensional (3D) image with higher DOF than that by traditional MLA and higher quality than that by ordinary double-layer MLA.
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20
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Chen PC, Chen LT, Yeh CS. Tunable microlens array fabricated by a silicone oil-induced swelled polydimethylsiloxane (PDMS) membrane bonded to a micro-milled microfluidic chip. OPTICS EXPRESS 2020; 28:29815-29828. [PMID: 33114872 DOI: 10.1364/oe.404637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
Microlens arrays (MLAs) nowadays are critical micro-optical components and they can be applied in many application fields, such as optical communication systems and flat panel display modules. This article describes a novel approach to the fabrication of tunable, highly reliable, and uniform polydimethylsiloxane (PDMS) MLAs. A polydimethylsiloxane (PDMS) membrane is bonded to a micro-milled poly(methyl methacrylate) (PMMA) microfluidic chip and exposed to silicone oil of a specific viscosity. Molecules in the oil insert themselves into the molecular structure of the PDMS membrane, causing it to swell and subsequently form dome-shaped MLAs. From our experiments, we derived the following conclusions. First, the homogeneous swelling of the PDMS resulted in MLAs with a high numerical aperture (0.5), high uniformity illumination (CV of the illumination intensity is between 2.5%∼5.1%), and high uniformity (CV of sag height of MLAs is less than 0.05). Second, the shorter molecular chains in low-viscosity oils diffused more readily into the PDMS membrane, which increased the effects on swelling, resulting in MLAs with higher sag height and higher numerical aperture. For example, the 5 cst silicone oil resulted in sag height of 191 µm with NA of 0.50, whereas the 100 cst silicone oil resulted in sag height of 86 µm with numerical aperture of 0.33. Finally, the integrated mixer module enabled the simultaneous tuning of the 7 × 7 MLAs simply by adjusting the injection flow rates of the constituent silicone oils.
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21
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Large-scale microlens arrays on flexible substrate with improved numerical aperture for curved integral imaging 3D display. Sci Rep 2020; 10:11741. [PMID: 32678158 PMCID: PMC7367310 DOI: 10.1038/s41598-020-68620-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 06/24/2020] [Indexed: 02/07/2023] Open
Abstract
Curved integral imaging 3D display could provide enhanced 3D sense of immersion and wider viewing angle, and is gaining increasing interest among discerning users. In this work, large scale microlens arrays (MLAs) on flexible PMMA substrate were achieved based on screen printing method. Meanwhile, an inverted reflowing configuration as well as optimization of UV resin's viscosity and substrate's surface wettability were implemented to improved the numerical aperture (NA) of microlenses. The results showed that the NA values of MLAs could be increased effectively by adopting inverted reflowing manner with appropriate reflowing time. With decreasing the substrate's wettability, the NA values could be increased from 0.036 to 0.096, when the UV resin contact angles increased from 60.1° to 88.7°. For demonstration, the fabricated MLAs was combined to a curved 2D monitor to realize a 31-inch curved integral imaging 3D display system, exhibiting wider viewing angle than flat integral imaging 3D display system.
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22
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Bae SI, Kim K, Yang S, Jang KW, Jeong KH. Multifocal microlens arrays using multilayer photolithography. OPTICS EXPRESS 2020; 28:9082-9088. [PMID: 32225521 DOI: 10.1364/oe.388921] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
We report a new microfabrication method of multifocal microlens arrays (MF-MLAs) for extended depth-of-field (DoF) using multilayer photolithography and thermal reflow. Microlenses of different focal lengths were simultaneously fabricated on a single glass wafer by using repeated photolithography with multiple photomasks to define microposts of different thicknesses and concurrent thermal reflow of multi-stacked microposts. The diverse lens curvatures of MF-MLAs are precisely controlled by the thickness of the micropost. Hexagonally packaged MF-MLAs clearly show three different focal lengths of 249 µm, 310 µm, and 460 µm for 200 µm in lens diameter and result in multifocal images on a single image sensor. This method provides a new route for developing various three-dimensional (3D) imaging applications such as light-field cameras or 3D medical endoscopes.
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23
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Zhou P, Yu H, Zou W, Zhong Y, Wang X, Wang Z, Liu L. Cross-scale additive direct-writing fabrication of micro/nano lens arrays by electrohydrodynamic jet printing. OPTICS EXPRESS 2020; 28:6336-6349. [PMID: 32225884 DOI: 10.1364/oe.383863] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/06/2020] [Indexed: 05/21/2023]
Abstract
High-quality micro/nanolens arrays (M/NLAs) are becoming irreplaceable components of various compact and miniaturized optical systems and functional devices. There is urgent requirement for a low-cost, high-efficiency, and high-precision technique to manufacture high-quality M/NLAs to meet their diverse and personalized applications. In this paper, we report the one-step maskless fabrication of M/NLAs via electrohydrodynamic jet (E-jet) printing. In order to get the best morphological parameters of M/NLAs, we adopted the stable cone-jet printing mode with optimized parameters instead of the micro dripping mode. The optical parameters of M/NLAs were analyzed and optimized, and they were influenced by the E-jet printing parameters, the wettability of the substrate, and the viscosity of the UV-curable adhesive. Thus, diverse and customized M/NLAs were obtained. Herein, we realized the fabrication of nanolens with a minimum diameter of 120 nm, and NLAs with different parameters were printed on a silicon substrate, a cantilever of atomic force microscopy probe, and single-layer graphene.
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24
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Yuan C, Kowsari K, Panjwani S, Chen Z, Wang D, Zhang B, Ng CJX, Alvarado PVY, Ge Q. Ultrafast Three-Dimensional Printing of Optically Smooth Microlens Arrays by Oscillation-Assisted Digital Light Processing. ACS APPLIED MATERIALS & INTERFACES 2019; 11:40662-40668. [PMID: 31589018 DOI: 10.1021/acsami.9b14692] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A microlens array has become an important micro-optics device in various applications. Compared with traditional manufacturing approaches, digital light processing (DLP)-based printing enables fabrication of complex three-dimensional (3D) geometries and is a possible manufacturing approach for microlens arrays. However, the nature of 3D printing objects by stacking successive 2D patterns formed by discrete pixels leads to coarse surface roughness and makes DLP-based printing unsuccessful in fabricating optical components. Here, we report an oscillation-assisted DLP-based printing approach for fabrication of microlens arrays. An optically smooth surface (about 1 nm surface roughness) is achieved by mechanical oscillation that eliminates the jagged surface formed by discrete pixels, and a 1-3 s single grayscale ultraviolet (UV) exposure that removes the staircase effect. Moreover, computationally designed grayscale UV patterns allow us to fabricate microlenses with various profiles. The proposed approach paves a way to 3D print optical components with high quality, fast speed, and vast flexibility.
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Affiliation(s)
- Chao Yuan
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Kavin Kowsari
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Sahil Panjwani
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Zaichun Chen
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Dong Wang
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Biao Zhang
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Colin Ju-Xiang Ng
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Pablo Valdivia Y Alvarado
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Qi Ge
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
- Department of Mechanical and Energy Engineering , Southern University of Science and Technology , Shenzhen 518055 , China
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Li H, Wang S, Zhao Y, Wei J, Piao M. 3D view image reconstruction in computational integral imaging using scale invariant feature transform and patch matching. OPTICS EXPRESS 2019; 27:24207-24222. [PMID: 31510314 DOI: 10.1364/oe.27.024207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/19/2019] [Indexed: 06/10/2023]
Abstract
This paper realizes a computational integral imaging reconstruction method via scale invariant feature transform (SIFT) and patch matching to improve the visual quality of reconstructed 3D view images. To our knowledge, the 3D view images reconstructed from the elemental images suffer from artifacts, which leads to degradations in the visual quality. To prevent image degradation, in this paper, we use the correct regions obtained from the view images taken directly from the original object or use patch matching to replace the distorted regions. However, the initial matching regions could not meet our requirements owing to the limitations of the equipment and the inevitable shortcomings of the experimental operation. To solve these problems, we adopt SIFT descriptors and perspective transform to get the satisfying correct regions. We present the simulation and experimental results of the 3D view images and the evaluation of the quality of the corresponding images to test the performance of the proposed method. The simulation and experimental results indicate that the proposed method can significantly improve the visual quality of the 3D view images and verify the feasibility and effectiveness of the proposed method.
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Liu Y, Li F, Qiu L, Yang K, Li Q, Zheng X, Hu H, Guo T, Wu C, Kim TW. Fluorescent Microarrays of in Situ Crystallized Perovskite Nanocomposites Fabricated for Patterned Applications by Using Inkjet Printing. ACS NANO 2019; 13:2042-2049. [PMID: 30735353 DOI: 10.1021/acsnano.8b08582] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Perovskite materials have exhibited promising potential for universal applications including backlighting, color conversion, and anticounterfeiting labels fabricated using solution processes. However, owing to the tendency of those materials to have uncontrollable morphologies and to form large crystals, they cannot be utilized in discontinuous microminiaturization, which is crucial for practical optoelectronic applications. In this research, combining the effects of adding polyvinylpyrrolidone (PVP), precisely controlling the inkjet printing technique, and using a postprocessing procedure, we were able to fabricate in situ crystallized perovskite-PVP nanocomposite microarrays with perfect morphologies. The viscosity of the perovskite precursor increased with the addition of PVP, eliminating the outward capillary flow that induces the coffee-ring effect. In addition, because of the presence of metallic bonds with the C═O groups in PVP and the spatial confinement of such a polymer, we were able to fabricate regulated CsPbBr3 nanocrystals capped with PVP and with a uniform size distribution. The as-printed patterns showed excellent homogeneity on a macroscale and high reproducibility on a microscale; furthermore, those patterns were invisible in the ambient environment, compatible with flexible substrates, and cost-efficient to produce, indicating that this technique holds promising potential for applications such as anticounterfeiting labels.
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Affiliation(s)
- Yang Liu
- Institute of Optoelectronic Technology , Fuzhou University , Fuzhou 350002 , People's Republic of China
| | - Fushan Li
- Institute of Optoelectronic Technology , Fuzhou University , Fuzhou 350002 , People's Republic of China
| | - Lichun Qiu
- Institute of Optoelectronic Technology , Fuzhou University , Fuzhou 350002 , People's Republic of China
| | - Kaiyu Yang
- Institute of Optoelectronic Technology , Fuzhou University , Fuzhou 350002 , People's Republic of China
| | - Qianqian Li
- Institute of Optoelectronic Technology , Fuzhou University , Fuzhou 350002 , People's Republic of China
| | - Xin Zheng
- Institute of Optoelectronic Technology , Fuzhou University , Fuzhou 350002 , People's Republic of China
| | - Hailong Hu
- Institute of Optoelectronic Technology , Fuzhou University , Fuzhou 350002 , People's Republic of China
| | - Tailiang Guo
- Institute of Optoelectronic Technology , Fuzhou University , Fuzhou 350002 , People's Republic of China
| | - Chaoxing Wu
- Department of Electronic Engineering , Hanyang University , Seoul 133-791 , Republic of Korea
| | - Tae Whan Kim
- Department of Electronic Engineering , Hanyang University , Seoul 133-791 , Republic of Korea
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27
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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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28
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Yang B, Zhou J, Chen Q, Lei L, Wen K. Fabrication of hexagonal compound eye microlens array using DMD-based lithography with dose modulation. OPTICS EXPRESS 2018; 26:28927-28937. [PMID: 30470062 DOI: 10.1364/oe.26.028927] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/20/2018] [Indexed: 06/09/2023]
Abstract
In this study, a method is proposed for the rapid fabrication of a hexagonal compound eye microlens array (HCE-MLA) using maskless lithography technique based on digital micromirror device (DMD), in which a hexahedron array is lithographed, and subsequently, a microlens structure is lithographed layer by layer upon the hexahedron. Owing to the high filling rate of the hexagon and the aspheric surface of the paraboloid profile of the microlens, after the distribution of the required exposure dose of HCE-MLA was calculated based on dose modulation, a series of circular pattern with different radius could be obtained by equal-arc-mean slicing strategy that can adapt to the variable curvature of the target contour and improve its reconstruction precision. Then, after a hexagonal photoresist island was fabricated on the substrate, and the dose accumulated over multiple exposures, the required exposure dose profiles were reconstructed on the hexagonal photoresist island. Finally, a high-quality HCE-MLA with a smooth surface was fabricated via thermal reflow. The fabrication of the designed HCE-MLA using this method was demonstrated in experiments. The results indicate that the actual profile of HCE-MLA shows good agreement with the design profile and that simultaneously increasing the number of the slicing layers can improve the quality of the profile. The research indicated that this method is feasible and convenient for the fabrication of high-quality HCE-MLA.
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Hu Y, Xiong Y, Chen X, Bai H, Tian Y, Liu G. Controllable long focal length microlens based on thermal expansion. APPLIED OPTICS 2018; 57:4277-4282. [PMID: 29791406 DOI: 10.1364/ao.57.004277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/22/2018] [Indexed: 06/08/2023]
Abstract
A novel method to fabricate a microlens array with a long focal length has been developed in this paper. It is based on the fabricating and heating of a microlens consisting of two materials with a great difference in coefficient of thermal expansion. A thermal expansion process leads to considerable deformation of the microlens surface and significant increase in focal length, which could be controlled by altering the processing temperature. Cylindrical polymeric microlens arrays with different focal lengths were successfully fabricated. By measuring the focal length and temperature dependence of the cylindrical microlens geometry, the formation mechanism was analyzed and validated. While the temperature is ranged from 20°C to 50°C, the focal length of the cylindrical microlens has been extended by 38.2% and the longest focal length was obtained up to 6.6 mm for the microlens with a linewidth of 240 μm.
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