Array Manufacturing Research Articles

Metasurface Optic Features Using Metal-Assisted Chemical Etching (MACE)

Metal-assisted chemical etching (MACE or MacEtch) is a versatile method for fabricating nano and micro-structured silicon (Si), which has garnered significant attention due to its potential applications in photovoltaics, sensors, and nanoelectronics. The process involves the oxidation of Si in the presence of a metal catalyst (typically noble metals like Au, Ag, or Pt) and a wet etch solution, usually comprising hydrofluoric acid (HF) and an oxidizing agent such as hydrogen peroxide (H2O2).Impressive work has already been completed in the two decades following the introduction of this method through the field of stain etching [1]. Researchers have reported anisotropic structures in silicon as high as 10,000:1 aspect ratio [2] and studied the impact of catalyst thickness [3], geometry [4], chemical ratios [5][6], and level of doping [7].In this work, we systematically tune the selectivity of the MACE process based on the geometry of desired structures, chemical ratios of HF, H2O2 and ethanol, silicon doping types, and characteristics of the metal catalyst targeting our desired metasurface optic features. We use statistical analysis such as ensemble machine learning algorithms to create an informed understanding and importance matrix for each of these variables, toward the purpose of creating refractive optical features in silicon. The important parameters in the desired final product are vertical sidewalls, 10:1 aspect ratio, minimized surface roughness in the field, an optimized geometry, and a target depth.This comprehensive statistical analysis contributes to a deeper understanding of the MACE process, offering valuable guidelines for optimizing etching conditions to achieve desired micron to nanometer structures in silicon. The findings hold promise for advancing the fabrication of silicon-based nano-devices, paving the way for novel applications in various technological fields. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525 SAND2024-04791A[1] X. Li and P. W. Bohn, "Metal-assisted chemical etching in HF/H2O2 produces porous silicon," Applied Physics Letters, vol. 77, no. 16, pp. 2572-2574, 2000, doi: 10.1063/1.1319191.[2] L. Romano et al., "Metal assisted chemical etching of silicon in the gas phase: a nanofabrication platform for X-ray optics," Nanoscale Horizons, 10.1039/C9NH00709A vol. 5, no. 5, pp. 869-879, 2020, doi: 10.1039/C9NH00709A.[3] Z. Huang et al., "Extended Arrays of Vertically Aligned Sub-10 nm Diameter [100] Si Nanowires by Metal-Assisted Chemical Etching," Nano Letters, vol. 8, no. 9, pp. 3046-3051, 2008/09/10 2008, doi: 10.1021/nl802324y.[4] P. Lianto, S.-Y. Yu, J. Wu, C. V. Thompson, and W. K. Choi, "Vertical etching with isolated catalysts in metal-assisted chemical etching of silicon," Nanoscale, vol. 4 23, pp. 7532-9, 2012. [Online]. Available: https://doi.org/10.1039/C2NR32350H.[5] C. Chartier, S. Bastide, and C. Lévy-Clément, "Metal-assisted chemical etching of silicon in HF–H2O2," Electrochimica Acta, vol. 53, no. 17, pp. 5509-5516, 2008/07/01/ 2008, doi: https://doi.org/10.1016/j.electacta.2008.03.009.[6] W. Chern et al., "Nonlithographic Patterning and Metal-Assisted Chemical Etching for Manufacturing of Tunable Light-Emitting Silicon Nanowire Arrays," Nano Letters, vol. 10, no. 5, pp. 1582-1588, 2010/05/12 2010, doi: 10.1021/nl903841a.[7] R. A. Lai, T. M. Hymel, V. K. Narasimhan, and Y. Cui, "Schottky Barrier Catalysis Mechanism in Metal-Assisted Chemical Etching of Silicon," ACS Applied Materials & Interfaces, vol. 8, no. 14, pp. 8875-8879, 2016/04/13 2016, doi: 10.1021/acsami.6b01020. Figure 1

An integrated hot embossing and thermal reflow method for precision manufacture of plano-convex glass microlens arrays

Plano-convex glass microlens arrays (MLAs) have broad applications in imaging, sensing, illumination, and communication systems. This paper proposed a three-step method to precision manufacture of plano-convex glass MLAs, which involves fabrication of SiC microhole arrays (MHAs), hot embossing of glass micropillar arrays (MPAs) and thermal reflow of glass MLAs. The effects of embossing temperature, force, and time on the replication accuracy of glass MPAs are evaluated. Subsequently, the glass MPAs with decent replication accuracy were subjected to thermal reflow experiments for studying the effects of reflowing temperature and reflowing time on the geometric features of formed glass MLAs. It is found that the height and tip curvature of reflowed glass microlenses can be controlled by adjusting the reflowing temperature and time. The warpage amplitudes and mean birefringence of most reflowed glass substrates are less than 5 μm and 27 nm/cm, respectively. Furthermore, the reflowed glass microlens arrays shows a decent uniformity in an area with a diameter of ∼4 mm. Finally, the feasibility of the integrated hot embossing and thermal reflow method in producing glass nano-lens arrays is also demonstrated. As a result, the hybrid forming technology that combines hot embossing with thermal reflow not only avoids the difficulties of fabrication of MLA and NLA mold inserts, but also possesses the advantages of high efficiency and low cost, which is expected to be a promising mass production technology for glass micro/nano-lens arrays.

(Invited) Nanowire Catalysts and Adsorbents

The unique properties of nanowire materials like fast charge transport, short diffusion length, controlled surface sites and single crystal nature make them ideal for designing high performance catalysts, adsorbents and electrocatalysts by design. To realize any of these applications, one would need either large quantities of nanowire powders or nanowire arrays on large areas. In this presentation, we will highlight our group’s efforts with scalable methods for continuous manufacturing of nanowire powders and arrays for oxides1 and III-nitride materials.2 The process for producing metal oxide nanowires has been scaled up to ton-scale. The resulting nanowire powders can be used to formulate unique catalyst and adsorbent products.Zinc oxide nanowires alloyed with catalytically active metals and have been formulated into ultra-deep desulfurization catalytic adsorbents.3,4 These materials exhibited ultra-deep desulfurization with sulfur removal down to 1 ppm or below for liquid hydrocarbons (diesel, gasoline and naphthalene) and to less than 1 ppb for natural gas. The desulfurization mechanism does not involve formation of H2S species unlike that typically observed with hydro-desulfurization process involving sulfided catalysts.Titania nanowires supported with nickel and molybdenum clusters have also shown to exhibit high activity and durability as hydro-desulfurization catalysts for removal of sulfur from hydrocarbons by forming H2S.5 The synergistic activity with MoS2 and titania are expected to contribute to enhanced activity with desulfurization.Alloying of nanowires with other elements is also studied to produce compound and alloyed nanowires. Fundamental studies have shown that alloying process occurs at much lower temperatures than decomposition temperatures for precursors used. Alloying studies have clearly shown that the solubility in nanowires to be much more than that expected for bulk materials systems. This presentation will provide several examples in which nanowires were alloyed with elements at compositions more than that expected for thermodynamic solubility.In the case of CO2 sorbents, alkali metal oxide nanowires have shown high capacity for CO2 sorption as high as 75% by wt. The alkali metal oxide nanowires have been alloyed with alkali hydroxides to produce alkali metal oxide compound nanowires. These solid sorbents showed selective CO2 sorption from a variety of streams including air, exhausts containing CO2 at various concentrations. Nanowire geometry for these nanowires allow for non-sinterability, and smaller length scales for rapid diffusion of alkali ions allow for fast kinetics and regenerability. 6,7 Acknowledgements: Authors also acknowledge contributions from Drs. Juan He, Sivakumar Vasireddy, Vivekanand Kumar, Veerendra Atla and Tu Nguyen. Partial support from National Science Foundation (NSF) and US Department of Energy (DOE) EPSCOR programs and full support from NSF and DOE SBIR programs and Kentucky Cabinet for Economic Development for Advanced Energy Materials, LLC are highly appreciated.

Optimizing etching depth for ultra-high brightness green micro-LED display development

In recent years, micro-light-emitting diode (micro-LED) displays have attracted much attention due to their high brightness, low power consumption, long lifetime, and fast response. It is considered to have the potential to revolutionize the development direction of next-generation visual display technology. However, the development of micro-LED displays faces numerous issues, primarily due to etching processes for pixel array manufacturing, which cause sidewall damage and decreased photoelectric efficiency. Specifically, these issues are particularly serious when preparing small-sized high-resolution displays. In this work, we effectively overcame the above-mentioned problems by only etching the electron barrier during the preparation process of pixel arrays. The prepared micro-LED display exhibits excellent optoelectronic properties, with the highest brightness and current efficiency reaching 1.66 × 106 nits and 104 cd/A, respectively. The method provides a feasible idea for preparing high-performance micro-LED displays.

Stress factors affecting protein stability during the fabrication and storage of dissolvable microneedles

Abstract Objectives The current review summarizes product and process attributes that were reported to influence protein integrity during manufacturing and storage of dissolvable microneedle arrays. It also discusses challenges in employing established protein characterization methods in dissolvable microneedle formulations. Methods Studies on dissolvable microneedles loaded with protein therapeutics that assess protein stability during or after fabrication and storage were collected. Publications addressing other types of microneedles, such as coated and vaccine-loaded microneedles, are also discussed as they face similar stability challenges. Key findings To date, various researchers have successfully incorporated proteins in dissolvable microneedles, but few publications explicitly investigated the impact of formulation and process parameters on protein stability. However, protein therapeutics are exposed to multiple thermal, physical, and chemical stressors during the fabrication and storage of microneedles. These stressors include increased temperature, shear and interfacial stress, transition to the solid state during drying, interaction with excipients, and suboptimal pH environments. While analytical methods are essential for monitoring protein integrity during manufacturing and storage, the performance of some well-established protein characterization techniques can be undermined by polymer excipients commonly employed in dissolvable microneedle formulations. Conclusions It is essential to understand the impact of key process and formulation parameters on the stability of protein therapeutics to facilitate their safe and effective administration by dissolvable microneedles.

Fabrication of Microstructure Arrays via Localized Electrochemical Deposition

Localized electrochemical deposition microadditive manufacturing (AM) (LECD-µAM) technology represents a nontraditional manufacturing method applied for the layer-by-layer fabrication of metal microstructures via a fully automatic feedback mechanism. In terms of material utilization and complex structure formation, the proposed technology exhibits great potential for microstructure fabrication. The LECD-µAM technology introduced in this study involves the reduction of metal cations in the electrolyte to form metal microstructures. This study showed the flow simulation of an electrolyte in the cantilever probe and pressure distribution at the probe tip. In addition, the effect of extrusion pressure on the deposition structure was investigated experimentally. Combined with the experimental results, we discussed the effects of LECD-µAM technology on deposition outcomes and optimized parameters and designed a printing route for the deposition of complex metal microstructure arrays with smooth surfaces. The proposed technology attained a deposition rate and a microstructural copper content of 0.961 µm/s and 99.5%. In addition, LECD-µAM technology can be performed at room temperature, has low environmental requirements and cost, provides a good deposition surface, and holds great potential for the manufacture of three-dimensional and other complex microstructure arrays.

Cu array fabrication: An environmentally sustainable approach through bicontinuous microemulsion differential electrodeposition for advanced power device packaging

BackgroundThe demand for high-power density packaging and integration processes for third-generation semiconductors, like silicon carbide (SiC), necessitates advancements beyond conventional Si-based packaging technologies. Cu-Cu direct bonding emerges as a promising alternative in semiconductor packaging. However, achieving Cu-to-Cu direct bonding with low-temperature, low-pressure, and short-time poses significant challenges. Transient Liquid Phase Bonding (TLP) offers a low-temperature joining solution, but prolonged reflow time hinders its wide applications. MethodsThis study introduces a novel strategy utilizing bicontinuous microemulsion (BME) electrodeposition to fabricate micron-sized Cu arrays, addressing these challenges in achieving Cu bonding. The core of Cu array manufacturing lies in the differential electrodeposition rate of Cu ions in the aqueous and organic phases. This principle is rooted in the excellent conductivity of the aqueous solution compared to the non-conductivity of the organic solution. Significant findingsWe elucidate the growth mechanism and validate a theory for achieving void-free optimal growth of Cu arrays within BME and compared the cross-sectional morphology and fracture modes of TLP solder joints with micron and nano Cu arrays. Furthermore, the ability to recycle the BME soft template aligns with green chemistry principles, offering a sustainable die-attach approach for third-generation semiconductor device packaging.

Optimization of stereolithography 3D printing of microneedle micro-molds for ocular drug delivery

Microneedles (MN) have emerged as an innovative technology for drug delivery, offering a minimally invasive approach to administer therapeutic agents. Recent applications have included ocular drug delivery, requiring the manufacture of sub-millimeter needle arrays in a reproducible and reliable manner. The development of 3D printing technologies has facilitated the fabrication of MN via mold production, although there is a paucity of information available regarding how the printing parameters may influence crucial issues such as sharpness and penetration efficacy. In this study, we have developed and optimized a 3D-printed MN micro-mold using stereolithography (SLA) 3D printing to prepare a dissolving ocular MN patch. The effects of a range of parameters including aspect ratio, layer thickness, length, mold shape and printing orientation have been examined with regard to both architecture and printing accuracy of the MN micro-mold, while the effects of printing angle on needle fidelity was also examined for a range of basic shapes (conical, pyramidal and triangular pyramidal). Mechanical strength and in vitro penetration of the polymeric (PVP/PVA) MN patch produced from reverse molds fabricated using MN with a range of shapes and height, and aspect ratios were assessed, followed by ex vivo studies of penetration into excised scleral and corneal tissues. The optimization process identified the parameters required to produce MN with the sharpest tips and highest dimensional fidelity, while the ex vivo studies indicated that these optimized systems would penetrate the ocular tissue with minimal applied pressure, thereby allowing ease of patient self-administration.

Fabrication of high-performance lens arrays for micro-concentrator photovoltaics using ultraviolet imprinting

Micro-concentrator photovoltaics (micro-CPV) is a cutting-edge CPV approach aimed at increasing the efficiency and reducing the cost and carbon footprint of solar electricity by downscaling concentrator solar cells and optics. The reduced size of micro-CPV provides several advantages over conventional CPV, including shorter optical paths and lower temperature and resistive losses in the cell, resulting in higher electrical efficiencies. This may increase the energy yield per area compared to conventional CPV or silicon modules. Cost reduction is achieved through material savings and the use of continuous manufacturing methods enabled by the tiny size of cells and optics, such as roll-to-roll (R2R) and roll-to-plate (R2P) ultraviolet (UV) imprinting for optics production. However, adapting these processes to large-area arrays of Fresnel micro-lenses with no wasted areas and high efficiency remains a challenge. In this study, we present a comprehensive methodology for the development of micro-CPV optics with full area coverage—from design and mastering to up-scaling, tooling, and replication. The methodology involves designing a non-rotationally symmetric elementary insert tailored to ultraviolet imprinting. Crucially, multiple inserts are originated via precision machining and recombined to form a single array master mold without wasted areas. The master is then replicated into a flexible working stamp for UV imprinting of Fresnel lens arrays, utilizing different UV curable materials. The functional characterization of the lenses demonstrates an optical efficiency of 80% at 178X under collimated white light, representing the highest effective concentration achieved using UV-imprinted Fresnel lenses. Furthermore, initial reliability tests confirm the absence of degradation during thermal cycling or outdoor exposure. This methodology paves the way for continuous high-throughput manufacturing of micro-lens arrays using R2R or R2P methods, presenting a significant step forward in micro-CPV.

All-Photolithography Fabrication of Ion-Gated Flexible Organic Transistor Array for Multimode Neuromorphic Computing.

Organic ion-gated transistors (OIGTs) demonstrate commendable performance for versatile neuromorphic systems. However, due to the fragility of organic materials to organic solvents, efficient and reliable all-photolithography methods for scalable manufacturing of high-density OIGT arrays with multimode neuromorphic functions are still missing, especially when all active layers are patterned in high-density. Here, a flexible high-density (9662 devices per cm2) OIGT array with high yield and minimal device-to-device variation is fabricated by a modified all-photolithography method. The unencapsulated flexible array can withstand 1000 times' bending at a radius of 1mm, and 3 months' storage test in air, without obvious performance degradation. More interesting, the OIGTs can be configured between volatile and nonvolatile modes, suitable for constructing reservoir computing systems to achieve high accuracy in classifying handwritten digits with low training costs. This work proposes a promising design of organic and flexible electronics for affordable neuromorphic systems, encompassing both array and algorithm aspects.

Femtosecond Laser Additive Manufacturing of Dual-Responsive Microstructure Arrays on Flexible Substrates (Invited)

Femtosecond Laser Additive Manufacturing of Dual-Responsive Microstructure Arrays on Flexible Substrates (Invited)

A Novel Multi-Modal Learning Approach for Cross-Process Defect Classification in TFT-LCD Array Manufacturing

A Novel Multi-Modal Learning Approach for Cross-Process Defect Classification in TFT-LCD Array Manufacturing

Efficiently building receive arrays with electromagnetic simulations and additive manufacturing: A two-layer, 32-channel prototype for 7T brain MRI.

We propose a comprehensive workflow to design and build fully customized dense receive arrays for MRI, providing prediction of SNR and g-factor. Combined with additive manufacturing, this method allows an efficient implementation for any arbitrary loop configuration. To demonstrate the methodology, an innovative two-layer, 32-channel receive array is proposed. The design workflow is based on numerical simulations using a commercial 3D electromagnetic software associated with circuit model co-simulations to provide the most accurate results in an efficient time. A model to compute the noise covariance matrix from circuit model scattering parameters is proposed. A 32-channel receive array at 7 T is simulated and fabricated with a two-layer design made of non-geometrically decoupled loops. Decoupling between loops is achieved using home-built direct high-impedance preamplifiers. The loops are 3D-printed with a new additive manufacturing technique to speed up integration while preserving the detailed geometry as simulated. The SNR and parallel-imaging performances of the proposed design are compared with a commercial coil, and in vivo images are acquired. The comparison of SNR and g-factors showed a good agreement between simulations and measurements. Experimental values are comparable with the ones measured on the commercial coil. Preliminary in vivo images also ensured the absence of any unexpected artifacts. A new design and performance analysis workflow is proposed and tested with a non-conventional 32-channel prototype at 7 T. Additive manufacturing of dense arrays of loops for brain imaging at ultrahigh field is validated for clinical use.

Gold Nanodrum Resonators.

Nanodrum resonators have been fabricated using nanometer-thick gold films as the drumheads. The fabrication method is favorable for large-area array manufacture of arbitrary shapes. The drum resonators exhibit fundamental mode vibration frequencies in the MHz regime. We use the stretched-plate model to describe the natural vibrations of the drum. The Q factor of the fundamental mode increases as the thickness of the drum increases and decreases as the drum diameter goes up. The highest Q factor of the fundamental mode reaches 290 at room temperature and atmospheric pressure. Based on the deduced material properties we estimate that the resonator has a mass sensitivity of 1.11 × 10-22 g/Hz.

A novel read circuit for RRAM based on RC delay effect

AbstractIn this paper, a novel Resistive Random‐Access Memory (RRAM) read circuit has been designed and verified by simulation based on the RRAM model and parasitic capacitance of the circuit. Simulation results demonstrate the feasibility and effectiveness of the proposed circuit, with accurate reading of RRAM states and fast reading speed in the nanosecond range. The sense margin of the proposed circuit has improved as the array size increases, enhancing its application for advanced node RRAM array manufacture. Compared with conventional circuits, the proposed circuit achieved power consumption reduction of 6% and area reduction of 46.9 um2, resulting in a 97.5% reduction in area, providing an effective solution to address the cost and chip size challenges associated with RRAM industrialization.

Electrolytic Characteristics of Microhole Array Manufacturing Using Polyacrylamide Electrolyte in 304 Stainless Steel.

Because of the ease with which oxide films form on its surfaces, stainless steel has strong corrosion resistance and excellent processing performance. Electrochemical machining (ECM) is a flexible process that can create microstructures on stainless steel (SS304); however, with traditional masked ECM, the efficiency and accuracy of microstructure machining are low. Proposed here is the use of a non-Newtonian fluid [polyacrylamide (PAM)] as the electrolyte. To date, there have been few papers on the electrochemical dissolution behavior of stainless-steel micromachining with a non-Newtonian fluid as the electrolyte. The aims of the study reported here were to investigate the electrochemical properties of SS304 with PAM and PAM-NaOH as electrolytes, and to explain their electrochemical corrosion mechanisms. The effects of different electrolytes were compared, and the polarization curves of SS304 in PAM and PAM-NaOH electrolyte solutions with different components were analyzed and compared with that in NaNO3 electrolyte. Then, the effects of the main processing parameters (pulse voltage, frequency, and duty ratio) on the machining performance were investigated in detail. A microhole array was obtained with a good quality comprising an average diameter of 330.11 µm, an average depth of 16.13 µm, and a depth-to-diameter ratio of 0.048. Using PAM to process microstructures on stainless-steel surfaces was shown to be feasible, and experiments indicated that the mixed electrolyte (PAM-NaOH) had not only the physical characteristics of a non-Newtonian fluid but also the advantages of a traditional electrolyte to dissolve processing products, and it effectively improved the processing accuracy of masked ECM for SS304.

Optical Characterisation of Plasmonic Indium Lattices Fabricated Via Electrochemical Deposition

Indium is an emerging plasmonic material that offers to extend the plasmonic applications given by gold and silver from the visible to the ultraviolet spectral range, with applications in imaging, sensing, and lasing. However, due to the high-vapor pressure/low melting temperature of indium, nanofabrication of pre-defined metallic indium nanostructures is non-trivial.In this work, we show the potential of selective area electrochemical deposition for the manufacturing of large-area arrays of indium pillars, which can be used for plasmonic applications. We combine electrochemical deposition with substrate-conformal imprint lithography to realize these large-scale indium nanoparticle arrays, having well-defined dimensions. This template growth results into well-defined hexagonal array of pillars with a mean height of 235 nm having a standard deviation of 60 nm.To highlight the potential of this electrochemical-based technique for plasmonic applications, we have performed angle-dependent extinction measurements using s-polarized light and using a RI matching oil. We found that these indium nanopillar arrays exhibit a strong plasmonic response due to the coupling to the plasmonic surface lattice resonances (SLRs). Furthermore, we have simulated the optical response of this indium nanopillar array using finite difference time domain (FDTD) simulations. In these simulations, we included the morphology obtained from SEM and the electrical permittivity of elemental indium. We found that the simulated extinction spectra agree well with the experimentally obtained spectra at 0˚ and 8˚ incidence, despite the polydispersity of the indium pillar height and defects in the hexagonal array.Our results therefore demonstrate the possibility of realizing large-area fabrication of indium plasmonic nanoparticles, which can be used for plasmonic applications. Given the low-cost and scalable nature of this technique, this work opens new possibilities in the design and fabrication of large-area plasmonic metasurfaces that operate in the UV spectral range. Future extensions of this work may leverage the indium mask-constrained growth to tailor even further the shape of the nanoparticle and hence give a powerful tuning knob to tailor plasmonic resonances.

Direct-Ink-Writing Printed Strain Rosette Sensor Array with Optimized Circuit Layout

The full-field multiaxial strain measurement is highly desired for application of structural monitoring but still challenging, especially when the manufacturing and assembling for large-area sensing devices is quite difficult. Compared with the traditional procedure of gluing commercial strain gauges on the structure surfaces for strain monitoring, the recently developed Direct-Ink-Writing (DIW) technology provides a feasible way to directly print sensors on the structure. However, there are still crucial issues in the design and printing strategies to be probed and improved. Therefore, in this work, we propose an integrated strategy from layered circuit scheme to rapid manufacturing of strain rosette sensor array based on the DIW technology. Benefit from the innovative design with simplified circuit layout and the advantages of DIW for printing multilayer structures, here we achieve optimization design principle for strain rosette sensor array with scalable circuit layout, which enable a hierarchical printing strategy for multiaxial strain monitoring in large scale or multiple domains. The strategy is highly expected to adapt for the emerging requirement in various applications such as integrated soft electronics, nondestructive testing and small-batch medical devices.

Scalable Manufacturing of Large-Area Pressure Sensor Array for Sitting Posture Recognition in Real Time.

Pressure sensors are considered the key technology for potential applications in real-time health monitoring, artificial electronic skins, and human-machine interfaces. Despite the significant progress in developing novel sensitive materials and constructing unique sensor structures, it remains challenging to fabricate large-area pressure sensor arrays due to the involvement of complex procedures including photolithography, laser writing, or coating. Herein, a scalable manufacturing approach for the realization of pressure sensor arrays with substantially enlarged sensitive areas is proposed using a versatile screen-printing technique. A compensation mechanism is introduced into the printing process to ensure the precise alignment of conductive electrodes, insulation layers, and sensitive microstructures with an alignment error of less than 4 μm. The fully screen-printed sensors exhibit excellent collective sensing performance, such as a reasonable pressure sensitivity of -2.2 kPa-1, a fast response time of 40 ms, and superior durability over 3000 consecutive pressures. Additionally, an integrated 16 × 32 pressure sensor array with a sensing area of 190 × 380 mm2 is demonstrated to precisely recognize the sitting postures and the body weights, showing great potential in continuous and real-time health status monitoring.

Neutron Pinhole Characterization and Analysis for Three-Dimensional As-Built Model Reconstruction

The neutron pinhole array, used to collect neutron burn, X-ray, and more recently, gamma emission images, has been in use at the National Ignition Facility since 2011. Since then, there has been the ever-continuing challenge of meeting tighter alignment and resolution requirements. Part of that challenge is being able to accurately characterize the as-built variances from the nominal design associated with the manufacturing and assembly of the pinhole array. To overcome this specific challenge, multiple processes are taken to obtain high-precision profiles of the various features of each pinhole array. This paper highlights the processes used as well as the steps taken to compile the significant amount of data and turn it into an accurate as-built reconstructed model of the NIS1-U–assembled pinhole array.