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Journal ArticleDOI

Design and fabrication of ultrathin lighting responsive security device based on moiré imaging phenomenon

01 Oct 2018-Optics Communications (North-Holland)-Vol. 424, pp 80-85
TL;DR: An ultrathin lighting responsive moire imaging device, which is different from traditional security device is developed for security authentication and allows its potential integration with banknotes, currency, or other valuable documents/products.
About: This article is published in Optics Communications.The article was published on 2018-10-01. It has received 7 citations till now.
Citations
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Journal ArticleDOI
02 Dec 2019-ACS Nano
TL;DR: The potential to selectively reveal more than one set of color patterns is demonstrated by rotating a microlens array relative to a print containing three overlapping arrays of structural color patterns in 10 ° steps, each pattern array can be distinctly revealed with minimal crosstalk.
Abstract: When a microlens array is aligned and overlaid on an array of patterns with similar periodicity, a highly magnified image of the patterns is observed. This effect, known as moire magnification, is ...

24 citations

Journal ArticleDOI
Yichen Tao1, Fuxin Cai1, Gangyao Zhan1, Hao Zhong1, Yun Zhou1, Su Shen1 
TL;DR: The proposed QR code device, capable of being read by an unmodified smart phone, is inexpensive, mass-producible, nondestructive, unclonable and convenient for authentication.
Abstract: Since the printing quick response (QR) code can be easily produced and duplicated as a potential tool for cybercriminals, QR code security has been a hotly debated issue across globe. Here we demonstrate a floating QR code device based on the moire principle which has the advantage of displaying an appealing three-dimensional (3D) effect and privacy protection. In the imaging system, the microlens array (MLA) contributes to efficiently sampling the multiple elemental images and the metal-coated nanostructure yields patterned structural black color with a high pattern resolution (>12, 500 dpi). A virtual mask scheme is specially developed in the elemental image construction, allowing for eliminating the crosstalk between neighboring units and containing more information in one unit without the necessity for ultra-high-resolution fabrication process and sophisticated operation. The proposed QR code device, capable of being read by an unmodified smart phone, is inexpensive, mass-producible, nondestructive, unclonable and convenient for authentication. This new solution should take a place among the existing solutions to fight counterfeiting and QR code attacks.

3 citations

Proceedings ArticleDOI
15 Feb 2022
TL;DR: In this paper , an RGB inkjet-printable full-color moiré imaging device with high resolution up to 4800 dpi was proposed. But the imaging heights are determined by the repeated period of the micropattern.
Abstract: Moiré imaging, achieved by superimposing a layer of microlens array (MLA) and micropattern array (MPA), has already be proven useful in a range of applications from art to engineering. Due to the sensitivity to small variations in the MPA , moiré imaging device require high resolution machine to produce. Here we report a colorful, inkjet-printable, resolution up to 4800 dpi moiré imaging device. By utilizing the RGB inkjet printing technology, full-color moiré image can be produced with strikingly visual effect. Moiré imaging device with large-format (<300mm) can be realized to achieve the visually striking motion and 3D effect as varying the viewing angle. The moiré image is coded as a micropattern packed repeatedly, and the imaging heights is determined by the repeated period of micropattern. Therefore, we achieve moiré image with complex imaging heights by varying the period of the micropattern. Injection molding process for manufacturing MLA, is a technology that has proven to be stable and reliable in actual production. The proposed moiré imaging device, with obvious 3D perception to the naked eye, is inexpensive, mass-producible and convenient for authentication. We demonstrate the quality of the device by theoretical calculation and manufacturing. Such device can find potential applications in the field of anti-counterfeiting, information encryption and decoration, etc.
Journal ArticleDOI
TL;DR: A new design method for moire magnifier based on depth cues from disparity is proposed and the period magnification, the rotation angle of moire pattern can be calculated, and the moire depth can be analyzed, too.
Abstract: Several methods have been developed to design and analyze moire magnifier, but these methods are all lack of quantitative consideration on the depth of moire imaging. In this paper, a new design method for moire magnifier based on depth cues from disparity is proposed. By using of the proposed method, the period magnification, the rotation angle of moire pattern can also be calculated, and the moire depth can be analyzed, too. According to the design and analysis results using MATLAB, the period of arrays and the cross angle are the important influence factors as the moire pattern above or below the microlens array. Moreover, with our 3D design method, we can design different moire magnifier with different size, direction angle and depth of moire pattern as required.
References
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Journal ArticleDOI
TL;DR: This work expands the visible color space through spatially mixing and adjusting the nanoscale spacing of discrete nanostructures to pave the way toward a new generation of low-cost, high-resolution, plasmonic color printing with direct applications in security tagging, cryptography, and information storage.
Abstract: We introduce the first plasmonic palette utilizing color generation strategies for photorealistic printing with aluminum nanostructures. Our work expands the visible color space through spatially mixing and adjusting the nanoscale spacing of discrete nanostructures. With aluminum as the plasmonic material, we achieved enhanced durability and dramatically reduced materials costs with our nanostructures compared to commonly used plasmonic materials such as gold and silver, as well as size regimes scalable to higher-throughput approaches such as photolithography and nanoimprint lithography. These advances could pave the way toward a new generation of low-cost, high-resolution, plasmonic color printing with direct applications in security tagging, cryptography, and information storage.

521 citations

Journal ArticleDOI
TL;DR: This work uses a combination of layer deposition techniques, including colloidal self-assembly, sputtering and atomic layer deposition, to fabricate photonic structures that mimic the colour mixing effect found on the wings of the Indonesian butterfly Papilio blumei and shows that a conceptual variation to the natural structure leads to enhanced optical properties.
Abstract: The brightest and most vivid colours in nature arise from the interaction of light with surfaces that exhibit periodic structure on the micro- and nanoscale. In the wings of butterflies, for example, a combination of multilayer interference, optical gratings, photonic crystals and other optical structures gives rise to complex colour mixing. Although the physics of structural colours is well understood, it remains a challenge to create artificial replicas of natural photonic structures. Here we use a combination of layer deposition techniques, including colloidal self-assembly, sputtering and atomic layer deposition, to fabricate photonic structures that mimic the colour mixing effect found on the wings of the Indonesian butterfly Papilio blumei. We also show that a conceptual variation to the natural structure leads to enhanced optical properties. Our approach offers improved efficiency, versatility and scalability compared with previous approaches.

363 citations

Journal ArticleDOI
TL;DR: Nanostructures and Their Applications Ali K. Yetisen, Izabela Naydenova,‡ Fernando da Cruz Vasconcellos,† Jeffrey Blyth,† and Christopher R. Lowe.
Abstract: Nanostructures and Their Applications Ali K. Yetisen,*,† Izabela Naydenova,‡ Fernando da Cruz Vasconcellos,† Jeffrey Blyth,† and Christopher R. Lowe† †Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, United Kingdom ‡Centre for Industrial and Engineering Optics, School of Physics, College of Sciences and Health, Dublin Institute of Technology, Dublin 8, Ireland

175 citations

Journal ArticleDOI
27 Jul 2009
TL;DR: This system begins with a user specification of a BRDF, or simply a highlight shape, and infers the required distribution of surface slopes, and samples this distribution, optimizing for a maximally-continuous and valley-minimizing height field, and mill the surface using a computer-controlled machine tool.
Abstract: We propose a system for manufacturing physical surfaces that, in aggregate, exhibit a desired surface appearance. Our system begins with a user specification of a BRDF, or simply a highlight shape, and infers the required distribution of surface slopes. We sample this distribution, optimize for a maximally-continuous and valley-minimizing height field, and finally mill the surface using a computer-controlled machine tool. We demonstrate a variety of surfaces, ranging from reproductions of measured BRDFs to materials with unconventional highlights.

139 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe the phenomenon of moire magnification, which occurs whenever an array of identical objects is viewed through a set of lenses with approximately the same pitch, and each moire fringe is in the form of a magnified and rotated image of the repeat element in the array.
Abstract: We describe the phenomenon of moire magnification, which occurs whenever an array of identical objects is viewed through an array of lenses with approximately the same pitch. As with any pair of similar grids, a moire pattern is seen, but in this case each moire fringe is in the form. of a magnified and rotated image of the repeat element in the object array.

125 citations