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Diffractive optical elements (DOE) are widely used in many different types of optical systems. These components played an enabling role e.g. in miniaturization of optical systems used in telecommunication, imaging and lithography, biomedical devices, optical sensors, vision correction and cameras.

The objective of this research is to develop a highly sensitive acoustic wave sensor using a tunneling current. The tunneling current device is fabricated with the hot embossing technology. Since polymethyl methacrylate (PMMA) is less expensive, has little stiffness, and is easier to work with micro-machining process compared to traditional silicon-based tunneling sensors, we fabricate the tip structure on the material using the hot embossing process. First, the frequency response of the tunneling device is measured by a piezoelectric transducer (PZT) and laser vibrometer to find the resonance frequency. Then the performance of the device is characterized by measuring the acoustic wave, which has the resonance frequency.

Roll-to-roll (R2R) process is mass manufacturing method that can produce various products ranging from printed electronics to microfluidics. Microfluidics, used in biosensors, demands high tolerances and quality to guarantee correct functionality of sensors. In this work, optical coherence tomography device was installed at the R2R-line to measure the height and width of the hot embossed microchannel structures at speed of 1m/min. The repeating channel structure on the 10 m long sample web was measured at 1m interval. An algorithm, typically used in wavelength scanning interferometry (WSI), is utilized to recover topography at nanometer scale. The results showed that the R2R hot embossing process was very stable and predictable. If process parameters, for instance pressure at the hot embossing unit was increased, it resulted deeper channels as expected. The OCT, with the WSI algorithm, provides topography of microchannel at nanometer scale being thus an excellent tool for optimization of process parameters and for on-line quality control.

A structure whose characteristic dimensions are on a microscale is called microstructure. To take advantage of their unique properties, these structures are used in a variety of fields. Whereas, the structure is on a micro-scale, it is difficult to use traditional manufacturing methods. There are many developed methods that can be used to form a microstructure. However, most of them are long lasting and difficult to control. In this study, the structure was formed very efficiently using the hot embossing method. This process was also simulated using a finite element model. The obtained results of structure formation will possibly be applied in further research.

The paper summarizes the experience with the development, production and optimization of 3D fabrics, specifically 3D weft knitted fabrics, planned for the integration of electronic components. Attention is focused on the presentation of 3D fabrics general properties which are given by their structure, used materials and finishing. The technological possibilities of preparation of this type of fabrics are summarized and their limits are described in detail and possible application areas are outlined. The possibilities of surface treatment from coating, lamination to printing or embossing are presented in order to optimize the fabric surface for a given application.

Printed electronics is key segment in modern fabrication of ultra-low-cost RFID/NFC/RF tags, smart labels, packaging, sensors etc. This paper shows the opportunity of usage of well known printing process called "offset printing" or "offset lithography". It is widely spread and well developed industry, but rarely used for printed electronics and smart tags. This work proposes usage of offset press on variety of substrates at high speed and large capacity production of printed electronics and also points to a connection of a lot of post-press technologies such as foil lamination, cutting, die-cutting, embossing, gluing etc. This additive technology provides an open door for smart packaging manufacturing, simply the RFID antenna can be printed by offset press directly on the substrate (usually paper) that is forming the box, smart label or sticker. Variety of substrates is also well maintained, offset press is usually equipped with UV, IR or hot air drying units, that enables printing on flexible substrates. More printing units also provides the technological possibility of layers overprinting.

Hierarchical micro-nanostructures comprising nanopillars superimposed onto micropillars were successfully fabricated over larger areas on thermoplastic cyclic olefin polymer (COP) substrates. Both the nanostructures (100 nm to 500 nm diameter) and microstructures (14-20 μm diameter) were hot-embossed monolithically using an intermediate fluorinated polymer mold replicated from a Si master. The as-fabricated thermoplastic hierarchical micro-nanopillar surfaces are superhydrophobic with advancing contact angles greater than 150°. Superhydrophobic surfaces with static contact angle as large as 167° were achieved on COP substrates using nanopillars as small as 150 nm and following post-fabrication fluorocarbon coating. The sliding angle of a water drop on the superhydrophobic surface is 2.5°., 2020 IEEE 20th International Conference on Nanotechnology (IEEE-NANO), July 29-31, 2020, Montreal, QC, Canada

This article presents the proposal for the design of a low-cost braille printer that implements OCR technology (Optical Character Recognition) through a mobile application with an algorithm that allows identifying text and images for braille translation or embossing tactile (Sequence connected with perforations on a sheet of paper that replicates by means related to points and lines about the main outline showing the figure or text detected). The objective coming from this prototype is to support teachers, parents or guardians about children who use the Braille system, facilitating the conversion process out from books, documents or any other educational material.

For the first time, we exploited a novel pump-free and high-throughput droplet generation method using the roller nanoimprint technology on biomimetic peristome surface of nepenthes. The biomimetic nepenthes peristome surfaces with oblique re-entrant microcavities and sharp edges led to facile directional liquid filling and high-efficiency droplet generation under the roller embossing, and the sealant on polyethylene terephthalate (PET) substrate encapsulated thousands of microcavities to form a high-density droplet array with good uniformity.

Medical mask is a common protective device. Its health and safety are directly related to the health of users. In this study, fast Fourier transform (FFT) and linear Gaussian (LGM) are applied to detect the defect of medical masks. The real-time detection and classification of rectangular length and width of mask, aluminum strip length, tooth arrangement defects and stains are realized. The experimental results show that the software system based on shape matching, two-dimensional measurement, fast Fourier transform and linear Gaussian can reduce the influence of embossing background on stain detection, and improve the detection accuracy effectively. The average measurement accuracy of mask width, ear band length and aluminum strip length are 0.6875mm, 2.6588mm and 0.2450mm respectively.

The contribution deals with technologies to transform conventional planar ceramic interposers like thick film and multilayer ceramic substrates into functional 3D geometries comparable to polymer based Molded Interconnect Devices (MID). Different technological approaches like folding, cold and hot Embossing, Ceramic Injection Moulding and Additive Manufacturing are discussed.

Harvesting energy from ambient mechanical motions is an effective and feasible method for solving limitations of conventional batteries. In this article, a highperformance large-scale and flexible triboelectric nanogenerator (TENG) for harvesting ambient mechanical energy is demonstrated. It has many advantages, such as easy scalability, good flexibility, high performance and low cost. The TENG works at cycled contact-separation mode between polyethylene terephthalate (PET) and Cu film. The performance is remarkably improved by patterning microstructures on PET film. Power density of the TENG can reach to 0.47 mW/cm3. The power obtained from the TENG is capable of lighting up as many as 105 LEDs instantaneously.

Fabrication of high performance tungsten microneedle array (MNA) which has tunable height and diameter is reported for the first time. Further, stable replication of cycloolefine copolymer (COC) MNA is achieved using novel vacuum isostatic hot embossing followed by PDMS casting with tungsten MNA mold. Radius of needlepoint is less than 1pm while microneedle height reaches as high as 100μm. High hardness of tungsten ensures reliability of mold which offers commercial potential for this method.

In the era of developing and automated as it is today, everything is required to be fast and timely. One of them is the entrepreneurial need to increase production capacity. Under these circumstances humans design a hot press machine with its suppressor using human power. But the hot press machine has a constant emphasis that the quality of production is not perfect. Seeing the problem, innovation is needed to get efficient results. One of them by designing pneumatic hot press printing machine. Therefore, the purpose of this research is to design conceptual pneumatic continuous system on hot press motif arising for synthetic material. Preparation of conceptual design of hot press machine with pneumatic starting with image design process, calculation analysis and machine planning. The press machine is designed to suppress the 520 N style using a 1.2 cm diameter cylinder rod, with a 3.2 cm diameter cylinder. Mattress width is, length: 30 mm, width 30 mm and minimum thickness 2 cm, with minimum thickness of 1 mm motif. The air discharge that must be flowed into the pneumatic cylinder is 0.48 ltr/min using a compressor power of 0.51 hp. Planning of installation of machine component that is covering cylinder base, ground work field, placement of pneumatic device, placement of heater and timer.

The lack of eyesight is a severe obstacle faced by the blind and limits their access to technology. Developments in assistive technology can be traced from the implementation of braille through engraving and embossing the script. With the growth of digital age, braille is included in keyboards and number pads and more recently as mechanical refreshable braille displays with integrated audio systems [8]. However, such systems are extremely expensive to purchase and maintain. Existing displays have a very low resolution and are bulky [5]. This project explores developments in ferrofluids, a type of magnetorheological liquid, and its possible applications in a magnetically controlled display layer. Also, electromagnets are used instead of conventional neodymium magnets. Variations in the coil shape and base shape are also explored. The aim is to achieve dimensions closer to existing mechanical braille systems. The models considered are analysed on COMSOL Multiphysics software [3]. Considerable improvement is achieved in reducing size to improve resolution. There is vast scope for further research in improving the system for commercial viability.

In roll-to-roll processing, the feeding speed of substrate ranging from several meters to several tens meters per minutes are required for some processes, such as roll-to-roll coating or gravure printing; reducing the speed will lead to other problems. On the other hand, some other processes need prolonged dwelling or holding time, such as thermal embossing. In the case of integrating different processes (for example, embossing and printing) into one roll-to-roll processing line, it is necessary to synchronize the feeding speeds of different processes. In this study, we will focus on thermal embossing process, discuss how the process speed, holding time will affect the fidelity of formed structures. Based on our investigation and comparison, we identified the problems of roll-to-roll thermal embossing, and developed a novel roll-to-roll embossing system. The developed system consists of two metallic belts — the top belt used for embossing template and the bottom belt for carrier. The developed system allows active driving from both sides of polymer films; it also provides an extended template-film contact time even with high speed roll-to-roll thermal embossing. This allows the roll-to-roll embossing to be integrated with other roll-to-roll manufacturing processes such as printing or coating.

R2R large area fabrication of functional panels gained popularity in recent years and micro 3D profiles for optical films and biomedical applications have gained momentum with improving replication accuracies in hot embossing systems. However, studies on the effect of heat flux on the replication accuracy have been lacking. In this study, a twin belt based roll-to-roll embossing system was designed and built to study the effects of various in-situ heat transfer at the hot embossing nip. Seamless embossing was then demonstrated on PVC film. The effects of different heat transfer schemes have been modeled using Solidworks simulation applying experimentally obtained mechanical properties of the polymer film. The simulation results are compared quantitatively to the experimental results to analyze the effect of heat transfer schemes on the replication accuracies. We achieved 92% replication accuracies on the PVC film replicated by application of heat on the side of the film not in contact with the mold. It is significantly higher than the features replicated using an isothermal condition at T g and also heat transfer from the mold. Thermal simulation shows a steep thermal gradient between the polymer under nip and the immediate surrounding for the isothermal conditions and a gentle thermal gradient for the other two schemes. Displacement of the polymer shows a highest flow of material from the surrounding of the feature for the underside heating method. This results in a more accurate replication onto the PVC film.

Nanoimprint is an emerging lithographic technology that promises high-throughput patterning of nanostructures. Based on the mechanical embossing principle, nanoimprint technique can achieve pattern resolutions beyond the limitations set by the light diffractions or beam scatterings in other conventional techniques. Nanoimprint can be applied to optical device, magnetic device, LSI device and so on.

Plasmonic antennas have been investigated as potential sensing element since long, but great part of the efforts on the nanofabrication have been devoted to the 2 dimensional patterning. Many times the the “sensing or probing” processes require geometries of the probe that are more complicated than the simple flat surface. In this paper we are going to show some example of three dimensional structures and their plasmonic properties as well as their application as sensors for IR spectroscopy and probes for Near-field scanning optical microscopy. We will present a series of structures and their characterization in IR as well as visible light. Particularly we will focus on the NSOM application. It is a powerful and unique approach to characterize the chemical, physical and biochemical properties of materials with the nanometer scale resolution in real-time [1]. One of the main challenges in using NSOM for a broad range of applications is the development of reproducible and efficient near-field probes. A novel class of nano-optical probes has been recently proposed, namely “campanile”. Campanile tips consist of a 3-Dimensional (3D) tapered structure terminated by a plasmonic nano-antenna, which provides superior NSOM performance and decisive advantages [2]. We will present a novel approach to drastically simplify the fabrication of Campanile probes by ultraviolet nanoimprint lithography (UV-NIL) directly on the facet of commercial optical fibers, without the need to use FIB (Fig. 1). The 3D mold is fabricated by a combination of polymer embossing and FIB lithography in a Helium Ion Beam. We will show some characterization [3] measurement as well as some NSOM hyperspectral images.

This study investigated the effect of capillary number on the micro embossing process. Computer-aided engineering simulation software was used to predict filling patterns of polymer materials inside the micro grooves mold cavities during the micro embossing process. Flow visualization technology and special mold design were employed to conduct real-time observation and record the deformations in the flow of polymer materials. Based on real-time recordings of the micro embossing process performed in this experiment by using visualization equipment, when C a > 0.15, a bimodal flow trend of polymer material occurred, and when C a < 0.15, a unimodal trend occurred. The simulation results were consistent with the visualization results.

Ultrasonic embossing and welding process is a fast and low cost manufacturing method for polymer devices in ambient temperature. More and more polymer MEMS devices, like optical devices and bio-MEMS devices are emerging in academic and engineering areas, due to the advantages of polymer materials, like low cost and easy manufacturing. In this paper, a buffer-assisted ultrasonic embossing process, using a layer of polymer film as buffer layer, was utilized to fabricate a flexible polymer optical diffuser, of which the height of the embossed microstructure is larger than the thickness of the polymer film. The optical experiment is conducted and the results verified the feasibility of the proposed buffer-assisted ultrasonic embossing process, so this buffer-assisted ultrasonic embossing process can be more polymer devices with large characteristic dimension form thin polymer films.

Thermoplastic is a common material in industrial products and it can be applied to microfluidic application since it is much more affordable and stable than PDMS in vary aspects. Based on former studies, a manufacturing process of thermoplastic microfluidic system is proposed, from the feature design to the final microfluidic device. The protocol being proposed is able to achieve rapid prototyping of multilayer thermoplastic microfluidic chips, improve the study efficiency of functional microfluidic product, shorten the period from laboratory to market as well as provide an alternative option for further developing microfluidic commercial products.

Conventional lithography techniques are limited to two-dimensional (2D) patterning and virtually rules out writing on the sides of the three dimensional (3D) structures. The advantages of patterned 3D micro-scale structures, in general are many, however existing technology does not provide cost-effective and robust schemes. Self assembly is seen as an attractive strategy for constructing highly parallel 3D micron scale structures that is described previously in our laboratory. Self assembly, in general is driven by spontaneous formation of structures to reach a minimum possible energy state. In this paper, we focus on forming different micro scale patterns on the sides of the 3D structures using a novel and robust solder based self assembly (SBSA) process. The SBSA method is demonstrated to obtain oblique patterns on the 3D side faces. SBSA includes planar techniques such as metal deposition, electroplating, wet-etching, optical-lithography, and a robust dip soldering method. Three different designs are patterned on the sides of the 3D structures in the form of inlaid designs, also called as damascene structures. Slight modification to the above process provides same designs in the form of emboss structures on 3D sides. The lowest feature size of these emboss and damascene structures are in the lower micron range. The desired designs are metal patterned on the 2D sacrificial layer. The 2D patterns are then dip soldered using a low melting point solder alloy. The etching of sacrificial layer frees the metal faces from the substrate except the central metal face that remains attached to the substrate. Finally, the patterned metal faces are self folded via solder reflow method to form patterned 3D faces which are filled with void-free solder. The folding yield of emboss and damascene patterns are compared and high resolution SEM images are analyzed.

Polystyrene was used to fabricate gradient index structure for terahertz antireflection via a hot-embossing process. Compared with a single non-structured antireflective layer, the gradient index structure increases transmittance by 20% and has broader enhanced bandwidth.

Roll-to-roll embossing is able to produce functional optical films with high throughput and lower cost, compared to other conventional manufacturing technologies such like injection molding. In roll-to-roll ultraviolet (UV) embossing, the functional microstructures on an optical film are directly replicated from a high-precision roller mold; the roller mold requires strict control of profile accuracy and optical surface quality which have to be achieved using ultra-precision machining technology. In this study, optical films with linear Fresnel lens array have been developed by using ultra-precision diamond tuning for mold fabrication and roll-to-roll UV embossing for transferring the features from mold to the flexible plastic substrates. The roller mould for making Fresnel lens array was designed in such a way that one Fresnel lens was composed of 166 tiny prisms and all prisms have an equal-feature-height of 0.1 mm, resulting in a focal length of 82.5 mm. With the optimized roll-to-roll UV embossing process, the Fresnel lens film produced in large area demonstrated strong light concentration effect on a solar simulation system, with light intensity increased by more than 6 times.

we have investigated roll-to-roll thermal embossing as well as roll-to-plate thermal embossing processes for large area, high aspect fabrication of microstructures on polymer films. Micro pillar arrays with diameter of 50 µm and pitch of 100 µm have been formed on polypropylene films as well as polycarbonate films under different embossing conditions. The micro pillar arrays can be used for light diffusing or for surface modification to improve surface hydrophobicity. In this paper, we will report achievements in thermal embossing and explore potential industrial applications.

This paper presents a simulation of polymeric embossing process utilizing ultrasonic vibrations. The embossing process is to use heat to soften the polymeric substrate around the die so that the polymer work piece is able to create the required feature of the die. However, the displaced materials from the embossing process will affect the overall dimensions of the embossed feature in the polymer with respect to the die's design. This investigation indicates that the heat generated at the polymer and die interface is caused by hysteresis heating which is a result of the mechanical vibrations generated by the ultrasonic horn. The rapid process of ultrasonic embossing has resulted in defects. This difficulty is usually addressed by experience or trials and errors through fine-tuning the processing parameters. Through finite element analysis, the ultrasonic embossing process can be visualized graphically. The flow pattern of the softened polymer during the embossing process can be visualised through simulation based on the input parameters, feature dimensions and polymer type. Comparisons are made between simulation and physical embossing experiment. This investigation indicates that FEM could provide a better understanding of the embossing process.

Reducing energy consumption in manufacturing processes through various methods, such as process improvement and proper machine design etc, is increasingly an important consideration. The amount of energy consumed by an embossing process can be considerable, with hidden factors which have to be considered. This paper examines the energy consumption of a traditional polymeric embossing system and an in-house developed system, and presents a comparison between them.

This paper presents with experimental evidence a novel technology for mass production of three-dimensional hollow or suspended microstructures. The technology does not require any steps involving micro injection molding or microstereolithography. Suspended or hollow microstructures are photolithographically formed at submillimeter resolution by shining a ultraviolet light (UV light) onto a photosensitive resin monomer that has been premixed with an UV-opaque impurity (referred hereafter as “resin-impurity composite”). Generally, the process flow comprises three stages. First, the resin-impurity composite is prepared. Second, an embossing stamp is made. Finally, microstructures are three-dimensionally casted using the embossing stamp from the second stage and, at the same time, hollow or suspended parts are photolithographically patterned and formed by UV exposure. A humidity proof package for RF-MEMS switches has been fabricated and is chosen as an example to demonstrate the feasibility of this technology.