Dielectric Elastomer Actuators (DEA) has great potential for low cost, high performance robotic and mechatronic devices. However, the reliability of these actuators remains an important issue when used in continuous strain applications. To improve actuators reliability, DEAs can be used in a binary or bistable manner where actuators flip between two stable positions, thus maintaining one of two equilibrium states without any electrical energy input. This paper presents an antagonistic bistable DEA concept using a single, planar polymer film that can lead to compact high force multilayered actuators. The system is made bistable by the addition of carbon fiber leaf springs designed to maximize actuator strain output. The strong viscoelastic nature of the chosen polymer film significantly affects the system’s output force and is accounted for in the Bergstrom-Boyce material model. The model shows good agreement with experimental stress relaxation curves and is used to set the leaf springs’ force curve. Experimental results have shown that the acrylic polymer film’s (VHB 4905) strong viscoelastic nature limits the actuator speed at ∼ 0.9 mm/s; at higher speeds, the leaf springs cannot be matched with the proposed concept. The study also demonstrates that the proposed antagonistic actuator configuration is an interesting solution to provide reliable bistable actuation for compact structures and that developing polymer films with low viscoelasticity is key for optimal performance.

This article discusses the current status and achievements of R2R technology for large area nano-scaled optical devices developed at MSL/ITRI. Firstly, a single layer of nanostructure on polymer film is designed for anti-reflection purpose by finite difference time domain (FDTD) method in the visible light spectrum. The conical array with around 1 aspect ratio, like moth-eye shape and showing superior performance in the optical simulation, has been adapted for the R2R experiments. The development of R2R process includes roller machine design and fabrication, roller mold design and making, development of rolling imprint process, characterization of rolled devices. In this study, large area (200mm *200mm) Ni template was fabricated with DUV exposure, followed by dry etching and electroforming process, respectively. Then, the template was bonded on the roller mold with magnetic film to make nanostructure roller mold. With the delicate nanostructure roller mold, systematic experiments have been conducted on the home-made roller machine with various parameters, such as linear speed, dose rate, and material modifications. The duplicated nanostructure films show very good optical quality of anti-reflection (AR < 1%) and are in good agreement with the theoretical predictions. Besides, the duration of the roller mold has been highly promoted to hundreds of imprint in the UV embossing process.

Recently, awareness of Corporate Social Responsibility (CSR) has been raised and various environmental regulations have spread in many countries. Under this situation, manufacturers of process production, production information management systems are required that can archive and retrieve data not only of final products and raw materials but of chemical substances contained, intermediate products and wastes generated, and energy consumption during the production. However, management systems and product models currently used for assembly production do not fit the above requirement. To solve the problem, first, an object-oriented process-product model was designed which can represent these data and can be easily implemented on commercial ORDBMS. Second, traceability functions of explosion and implosion covering chemical substances, intermediate products, wastes and energy were developed on the ORDBMS. Third, a generic environmental law model was designed which can represent restrictions of various environmental regulations in a uniform way. Finally, a conformance checking function for environmental regulations was developed by combining the generic environmental law model with the process-product model. The effectiveness of the models and functions was verified by applying them to full-scale production data of functional polymer films and checking its conformance to RoHS and EuP directives.

Temperature profiles in PET (Polyethylene Terephtalate), PBT (Polybutylene Terephtalate), and PS (Polystyrene) films created due to excimer laser irradiation were estimated analytically from the model of semi-infinite heat flux and numerically from the model based on 1-D heat equation. For the analytical estimation of temperature profile, we initially assumed that all of the irradiated excimer laser energy was confined in surface, and the energy was considered as a constant heat flux during the laser irradiation period. Calculation results showed that this assumption is somewhat inadequate for polymer materials especially for the polymers with low UV absorption coefficients, because we could not exclude the absorption of excimer laser energy in bulk. In order to reduce the error from this assumption, temperature profiles were estimated from numerical solution, which included a heat generating function representing absorption of excimer laser beam in polymer. Temperature measurement results showed a good agreement with this calculation, but only when ablation was not significant (i.e., for PS).