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Dai X, Shan Y, Wang D, Yang T, Cheng D, Wang Y. Mapping-based design method for high-quality integral projection system. OPTICS EXPRESS 2024; 32:18379-18398. [PMID: 38858995 DOI: 10.1364/oe.520766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 04/15/2024] [Indexed: 06/12/2024]
Abstract
A general method for designing an integral projection system is proposed, including optical design and digital preprocessing based on the mapping within the projection system. The per-pixel mapping between the sub-images and the integral projection image is generated by incorporating an integral projection imaging model as well as the ray data of all sub-channels. By tracing rays for sparsely sampled field points of the central sub-channel and constructing the mapping between the central sub-channel and other sub-channels, the efficient acquisition of ray data for all sub-channels is achieved. The sub-image preprocessing pipeline is presented to effectively address issues such as overlapping misalignment, optical aberrations, inhomogeneous illumination, and their collective contribution. An integral projection optical system with a field of view (FOV) of 80°, an F-number of 2, and uniform image performance is given as a design example. The ray tracing simulation results and quantitative analysis demonstrate that the proposed system yields distortion-free, uniformly illuminated, and high-quality integral projection images.
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Song TE, Oh SA, Ahn CW, Oh IK, Jeon HJ. Effective Approach for Fabricating Highly Precise High-Curvature Structural Patterns via Air-Bubble Induction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:15785-15791. [PMID: 37880817 DOI: 10.1021/acs.langmuir.3c02454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Developing a new master mold-based patterning technology that can be used to accurately, precisely, and uniformly create large-area micropatterns while controlling the micropatterns of curved structures is essential for promoting innovative developments in various application fields. This study develops a new top-down lithographic process that can effectively produce structural patterns with high curvatures by growing isolated microbubbles in the master pattern holes. The isolated air-pocket lithography (IAL) we developed is based on the controlled behavior of micrometer-sized air pockets trapped between the grooves of the master pattern and the curable polymer. We successfully fabricated a concave array polydimethylsiloxane (PDMS) film and a convex array polymer film. In addition, the IAL mechanism was proven by confirming the expansion process of micrometer-sized air pockets trapped between the deep groove of the silicon master pattern and the PDMS coating film by using optical microscopy images. We successfully obtained complex three-dimensional structural patterns containing both 3D hollow spherical concave and ring-shaped two-dimensional convex patterns. This simple, fast, and effective high-curvature patterning technique is expected to provide innovative solutions for future applications such as nanoelectronics, optical devices, displays, and photovoltaics.
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Affiliation(s)
- Tae-Eun Song
- National Creative Research Initiative Center for Functionally Antagonistic Nano-Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sang-Ah Oh
- Department of Chemical Engineering and Biotechnology, Tech University of Korea, 237, Sangidaehak-ro, Si-heung-si, Gyeonggi-do 15073, Republic of Korea
| | - Chi Won Ahn
- National Nano Fab Center (NNFC), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Il-Kwon Oh
- National Creative Research Initiative Center for Functionally Antagonistic Nano-Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hwan-Jin Jeon
- Department of Chemical Engineering and Biotechnology, Tech University of Korea, 237, Sangidaehak-ro, Si-heung-si, Gyeonggi-do 15073, Republic of Korea
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Artificial Compound Eye Systems and Their Application: A Review. MICROMACHINES 2021; 12:mi12070847. [PMID: 34357257 PMCID: PMC8307767 DOI: 10.3390/mi12070847] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/08/2021] [Accepted: 07/15/2021] [Indexed: 12/24/2022]
Abstract
The natural compound eye system has many outstanding properties, such as a more compact size, wider-angle view, better capacity to detect moving objects, and higher sensitivity to light intensity, compared to that of a single-aperture vision system. Thanks to the development of micro- and nano-fabrication techniques, many artificial compound eye imaging systems have been studied and fabricated to inherit fascinating optical features of the natural compound eye. This paper provides a review of artificial compound eye imaging systems. This review begins by introducing the principle of the natural compound eye, and then, the analysis of two types of artificial compound eye systems. We equally present the applications of the artificial compound eye imaging systems. Finally, we suggest our outlooks about the artificial compound eye imaging system.
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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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Liang Y, Zhu T, Xi M, Abbasi HN, Fu J, Su R, Song Z, Wang K, Wang H. Fabrication of concave microlenses on a diamond by a spin coating process. OPTICS EXPRESS 2020; 28:9320-9326. [PMID: 32225541 DOI: 10.1364/oe.383640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 03/02/2020] [Indexed: 06/10/2023]
Abstract
In this study, to fabricate diamond concave microlenses in a simple manner, an approach that combines a spin coating process with subsequent dry etching was demonstrated. First, photolithography was used to produce cylindrical holes in the photoresist layer on the diamond surface. Then, another photoresist was spin coated to fill the holes, and the concave structures with meniscus shapes were then obtained because of centrifugal force and interfacial tension. Finally, diamond concave microlenses were formed by transferring photoresist concave structures onto a diamond substrate using a dry etching technique. The fabricated diamond microlens exhibits a low surface roughness with nanometers as well as high-quality imaging and focusing performances, which is expected to have a wider range of potential applications under harsh and special conditions.
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Kim K, Jang KW, Ryu JK, Jeong KH. Biologically inspired ultrathin arrayed camera for high-contrast and high-resolution imaging. LIGHT, SCIENCE & APPLICATIONS 2020; 9:28. [PMID: 32140219 PMCID: PMC7046746 DOI: 10.1038/s41377-020-0261-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/10/2020] [Accepted: 02/13/2020] [Indexed: 06/10/2023]
Abstract
Compound eyes found in insects provide intriguing sources of biological inspiration for miniaturised imaging systems. Here, we report an ultrathin arrayed camera inspired by insect eye structures for high-contrast and super-resolution imaging. The ultrathin camera features micro-optical elements (MOEs), i.e., inverted microlenses, multilayered pinhole arrays, and gap spacers on an image sensor. The MOE was fabricated by using repeated photolithography and thermal reflow. The fully packaged camera shows a total track length of 740 μm and a field-of-view (FOV) of 73°. The experimental results demonstrate that the multilayered pinhole of the MOE allows high-contrast imaging by eliminating the optical crosstalk between microlenses. The integral image reconstructed from array images clearly increases the modulation transfer function (MTF) by ~1.57 times compared to that of a single channel image in the ultrathin camera. This ultrathin arrayed camera provides a novel and practical direction for diverse mobile, surveillance or medical applications.
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Affiliation(s)
- Kisoo Kim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- KAIST Institute for Health Science and Technology, KAIST, Daejeon, 34141 Republic of Korea
| | - Kyung-Won Jang
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- KAIST Institute for Health Science and Technology, KAIST, Daejeon, 34141 Republic of Korea
| | - Jae-Kwan Ryu
- Unmanned/Robotic Systems Lab., LIG Nex1 Co. Ltd, Seongnam, 13488 Republic of Korea
| | - Ki-Hun Jeong
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- KAIST Institute for Health Science and Technology, KAIST, Daejeon, 34141 Republic of Korea
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Zhang Y, Luo J, Xiong Z, Liu H, Wang L, Gu Y, Lu Z, Li J, Huang J. User-defined microstructures array fabricated by DMD based multistep lithography with dose modulation. OPTICS EXPRESS 2019; 27:31956-31966. [PMID: 31684417 DOI: 10.1364/oe.27.031956] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/15/2019] [Indexed: 06/10/2023]
Abstract
A flexible and efficient strategy, digital micromirror devices (DMD) based multistep lithography (DMSL), is proposed to fabricate arrays of user-defined microstructures. Through the combination of dose modulation, flexible pattern generation of DMD, and high-resolution step movement of piezoelectrical stage (PZS), this method enables prototyping a board range of 2D lattices with periodic/nonperiodic spatial distribution and arbitrary shapes and the critical feature size is down to 600 nm. We further explore the use of DMSL to fabricate microlens array by combining with the thermal reflowing process. The square shape and hexagonal shape microlens with customized distribution are realized and characterized. The results indicate that the proposed DMSL can be a significant role in the microfabrication techniques for manufacturing functional microstructures array.
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Zhu TF, Fu J, Liu Z, Liang Y, Wang W, Wen F, Zhang J, Wang HX. Investigation of the occupancy ratio dependence for microlens arrays on diamond. RSC Adv 2018; 8:29544-29547. [PMID: 35547301 PMCID: PMC9085271 DOI: 10.1039/c8ra03803a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/18/2018] [Indexed: 01/02/2023] Open
Abstract
Diamond microlens arrays with a high occupancy ratio were fabricated by an improved thermal reflow method.
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Affiliation(s)
- Tian-Fei Zhu
- Institute of Wide Band Gap Semiconductors
- Xi'an Jiaotong University
- Xi'an
- PR China
| | - Jiao Fu
- Institute of Wide Band Gap Semiconductors
- Xi'an Jiaotong University
- Xi'an
- PR China
| | - Zongchen Liu
- Institute of Wide Band Gap Semiconductors
- Xi'an Jiaotong University
- Xi'an
- PR China
| | - Yan Liang
- Institute of Wide Band Gap Semiconductors
- Xi'an Jiaotong University
- Xi'an
- PR China
| | - Wei Wang
- Institute of Wide Band Gap Semiconductors
- Xi'an Jiaotong University
- Xi'an
- PR China
| | - Feng Wen
- Institute of Wide Band Gap Semiconductors
- Xi'an Jiaotong University
- Xi'an
- PR China
| | - Jingwen Zhang
- Institute of Wide Band Gap Semiconductors
- Xi'an Jiaotong University
- Xi'an
- PR China
| | - Hong-Xing Wang
- Institute of Wide Band Gap Semiconductors
- Xi'an Jiaotong University
- Xi'an
- PR China
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Zhu TF, Fu J, Wang W, Wen F, Zhang J, Bu R, Ma M, Wang HX. Fabrication of diamond microlenses by chemical reflow method. OPTICS EXPRESS 2017; 25:1185-1192. [PMID: 28158003 DOI: 10.1364/oe.25.001185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We introduce a chemical reflow method to fabricate diamond microlenses. First, photoresist pillars developed by photolithography are reflowed in organic solvent vapor atmosphere at 20 °C to form spherical segment patterns on diamond substrate. The effects of chemical solvent type and reflow time on photoresist pattern profiles are investigated. Second, via dry etching, diamond microlenses are fabricated by transferring the spherical segment pattern into substrate. Furthermore, these diamond microlenses demonstrate low numerical aperture, well-controllable curvature, and good imaging performance with projecting experiment.
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Zhou X, Peng Y, Peng R, Zeng X, Zhang YA, Guo T. Fabrication of Large-Scale Microlens Arrays Based on Screen Printing for Integral Imaging 3D Display. ACS APPLIED MATERIALS & INTERFACES 2016; 8:24248-24255. [PMID: 27540754 DOI: 10.1021/acsami.6b08278] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The low-cost large-scale fabrication of microlens arrays (MLAs) with precise alignment, great uniformity of focusing, and good converging performance are of great importance for integral imaging 3D display. In this work, a simple and effective method for large-scale polymer microlens arrays using screen printing has been successfully presented. The results show that the MLAs possess high-quality surface morphology and excellent optical performances. Furthermore, the microlens' shape and size, i.e., the diameter, the height, and the distance between two adjacent microlenses of the MLAs can be easily controlled by modifying the reflowing time and the size of open apertures of the screen. MLAs with the neighboring microlenses almost tangent can be achieved under suitable size of open apertures of the screen and reflowing time, which can remarkably reduce the color moiré patterns caused by the stray light between the blank areas of the MLAs in the integral imaging 3D display system, exhibiting much better reconstruction performance.
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Affiliation(s)
- Xiongtu Zhou
- College of Physics and Information Engineering, Fuzhou University , 350002 Fuzhou, Fujian, PR China
| | - Yuyan Peng
- College of Physics and Information Engineering, Fuzhou University , 350002 Fuzhou, Fujian, PR China
| | - Rong Peng
- College of Physics and Information Engineering, Fuzhou University , 350002 Fuzhou, Fujian, PR China
| | - Xiangyao Zeng
- College of Physics and Information Engineering, Fuzhou University , 350002 Fuzhou, Fujian, PR China
| | - Yong-Ai Zhang
- College of Physics and Information Engineering, Fuzhou University , 350002 Fuzhou, Fujian, PR China
| | - Tailiang Guo
- College of Physics and Information Engineering, Fuzhou University , 350002 Fuzhou, Fujian, PR China
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