No abstract

This paper reports the design, fabrication and control of arrayed microelectromechanical systems (MEMS)-based actuators for distributed micromanipulation by generation and control of an air-flow force field. The authors present an original design of pneumatic microactuator, improving reliability and durability of a distributed planar micromanipulator described in the previous study. The fabrication process is based on silicon-on-insulator (SOI) wafer and HF (hydroflouric acid) vapor release, which also significantly increases the production yield of the 560 microactuator array device of 35 35 mm 2 . Minimization of the electrostatic actuation pull-in voltage through suspension shaping fabrication was also studied, and successfully validated for electrical efficiency improvement. A distributed control method to achieve good conveyance performance and reduce motion control instability was investigated. An emulation approach was chosen to validate a decentralized control strategy on the distributed active surface in order to conduct a proof-of-concept of a future smart structure, integrating sensors, intelligence, and microactuators. Thus, a centralized/decentralized control flow, inspired by autonomous mobile robot principles, was applied. It was modeled and implemented using C-programming language. Experimental and characterization results validate the control method for feedback micromanipulation with good velocity and load capacity performance.[1605]

A shadow mask with high pattern flexibility is realized by deep reactive ion etching (RIE) on Si wafer. The novel features of the mask are the presence of a mechanical alignment structure and of patterns with isolated islands inside them. The advantage of this shadow mask is the possibility of deposition of any kind of pattern shape by evaporation or sputtering on a sample that is precisely positioned. Moreover, by this technique, deposition is realized without damaging electronic devices or micromachined structures on the sample. Precise positioning of the sample with respect to the shadow mask is allowed by the mechanical alignment structures. Some doughnut-shape-like patterns are obtained by deposition through the patterns with isolated islands inside them. In this article we will describe the realization and the application of such a shadow mask.

No abstract

No abstract

No abstract

We propose a microconveyor based on silicon microelectromechanical systems (MEMS) technology and demonstrate successful operation of the microconveyor. Microactuators work as air nozzles, which generate directed air flow by changing the pathways of compressed nitrogen gas. One-dimensional conveyance of an object 2.1mm × 4.1mm × 200μm weighing approximately 4mg is demonstrated with a directed air flow of 17kPa. Using a two-dimensional conveyor, we levitate and move an object 3mm × 3mm × 100μm weighing approximately 2mg using a continuous air flow. Conveyance toward the force equilibrium point was achieved with a regularly pulsed air flow. We are now studying full control of two-dimensional conveyance. We also propose control by actuating air nozzles to change the direction of air flow and move the equilibrium point to transfer the object to the desired point.

Field-effect transistor (FET)-based biosensors have a wide range of applications, and a bio-FET odorant sensor, based on insect (Sf21) cells expressing insect odorant receptors (ORs) with sensitivity and selectivity, has emerged. To fully realize the practical application of bio-FET odorant sensors, knowledge of the cell–device interface for efficient signal transfer, and a reliable and low-cost measurement system using the commercial complementary metal-oxide semiconductor (CMOS) foundry process, will be indispensable. However, the interfaces between Sf21 cells and sensor devices are largely unknown, and electrode materials used in the commercial CMOS foundry process are generally limited to aluminium, which is reportedly toxic to cells. In this study, we investigated Sf21 cell–device interfaces by developing cross-sectional specimens. Calcium imaging of Sf21 cells expressing insect ORs was used to verify the functions of Sf21 cells as odorant sensor elements on the electrode materials. We found that the cell–device interface was approximately 10 nm wide on average, suggesting that the adhesion mechanism of Sf21 cells may differ from that of other cells. These results will help to construct accurate signal detection from expressed insect ORs using FETs.