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We developed a tunable wedge prism by electrowetting actuation. Our prism can shift the field of view to the left or to the right and is useful for small cameras and endoscopes because its field of view can be changed without the need for large instruments. It consists of two plates that face each other, and a liquid is sandwiched between them. The liquid and plates form a wedge when the angle between the plates is changed. We used electrowetting to change the angle between the plates. The wedge prism is small because the liquid driven by electrowetting works as a prism. In addition, the prism produces a clear field of view because its optical flatness is determined by the flatness of the plates. [2007-0079] Index Terms--Electrostatic devices, microelectromechanical devices, optical device fabrication.

In this paper, we have developed a process for multistep sequential batch assembly of complex three-dimensional (3-D) ferromagnetic microstructures. The process uses the magnetic torque generated by an external magnetic field perpendicular to the substrate to lift hinged structures. We found that a dimensionless factor that depends on the volume of the magnetic material and the stiffness of the hinges determines the sensitivity of the hinged microstructures to a magnetic field. This factor was used as a criterion in designing a process for sequential batch assembly, i.e., for setting appropriate differences in sensitivity. Using a dimensionless factor in the design of the sequential assembly simplified the assembly process, which requires only placing the structures on a permanent magnet, and which can be used to carry out multistep sequential batch assembly. We fabricated hinged microstructures, which consist of 4.5-[micro]m-thick electroplated Permalloy plates and 200-nm-thick nickel elastic hinges of various sizes. In an experiment, four plates (600 [micro]m x 800 [micro]m) were lifted sequentially and out-of-plane microstructures were assembled in a four-step process. Assembly of more complex out-of-plane microstructures (e.g., regular tetrahedrons, 800 [micro]m long on one side) was also shown to be feasible using this method of sequential batch assembly. Index Terms--Batch assembly, elastic hinges, magnetostatic torque, sequential assembly, three-dimensional (3-D) microstructures.

This paper describes three-dimensional micro-self-assembly using hydrophobic interaction. The interaction between microparticles was controlled using self-assembled monolayers formed on the particles. The particles were stirred in a dispersion liquid to create a binding for connecting their surfaces directly. The interaction between the particles was described by the thermodynamic free energy of adhesion, which was calculated using the surface free energies of the solids and the liquid. The calculated free energy was then used to predict the bindings between particles. The binding probability was estimated by counting the number of microparticles that became bound to hydrophobic and to hydrophilic areas patterned on a substrate. The ratio of the bound particles was correlated to the difference between the free energies of the two areas, as predicted using the free energy calculation. This means that microparticle binding is controlled by the surface properties. Structures composed of several microparticles were successfully self-assembled using this principle. Hydrophobic interaction can thus be applied to micro-scale self-assembly. [1143] Index Terms--Free energy of adhesion, hydrophobic interaction, self-assembled monolayers, self-assembly.

A radio frequency (RF) telemetry system with a shape memory alloy microelectrode was designed and fabricated. The total size and weight are 15 mm x 8 mm and 0.1 g, respectively. Since the telemeter is small and light enough to be loaded on a small animal such as an insect, the system can be used for the neural recording of a freely moving insect. The RF-telemeter can transmit signals by frequency modulation transmission at 80-90 MHz. The transmitted signals can be received up to about 16 meters away from the telemeter with a high signal-to-noise ratio. The neural activity can be detected without attenuation by using an instrumentation amplifier with its input impedance set to 2 M[ohm] at 1 kHz. The telemeter was loaded on a cockroach and the neural activity during a free-walk was successfully measured through this telemetry system. Index Terms--FM transmitter, free-walking, insect, neural recording, RF-telemetry, wireless recording.

This paper presents microsized soft-magnetic rotational wings in an alternating magnetic field. The wireless power supply as well as control of magnetic microwings are readily applicable to microflight mechanisms. As a magnetic material, soft magnetic material, such as nickel-iron alloy was deposited via electroplating, which is a well-developed MEMS batch process. The magnetization of the soft-magnetic device, however, changes its direction and magnitude during rotation, where the shape magnetic anisotropy of the wings plays a vital role. The principle of the wing rotation in an alternating magnetic field was elucidated theoretically and showed favorable agreement with the experimental results with large-sized models. The aerodynamic performances of soft magnetic rotational wings were evaluated, including the microrotational wings 165 [micro]g in weight consisting of 0.9-mm-long magnetic wings made of electroplated nickel-iron alloy and an axis of wing rotation made of a sharpened glass tube. The micromagnetic rotational wings presented here were utilized for microflight mechanisms, which achieved successful flights. [765] Index Terms--Microflight mechanism, microwings, rotational mechanism, soft-magnetic actuator.

As the benefits of minimally invasive surgery are recognized, the rate of laparoscopic liver resection (LLR) is rapidly increasing. Liver tissue is fragile compared to tissue of the stomach and colon. In endoscopic and robotic surgery, sufficient tactile sensation is yet to be obtained. Therefore, it is necessary to measure and indicate the grip force of forceps during surgery. We developed a new device consisting of force sensors and investigated its grip force and the resulting histological damage to liver tissue. We measured the grip force generated during laparoscopic surgery in pigs using the forceps with pressure sensors developed by us. Throughout the hepatectomy, we measured the grip force generated by the forceps in real time. We investigated the histological damage to the liver caused by using the forceps with different grip forces. The subject produced a mean grip force of 1.75 N during the procedures. The maximum grip force was 3.38 N. By grasping the tissues of the liver with forceps, bleeding and destruction of the hepatic lobules were observed in a manner dependent on increasing grip force. The new device is necessary for preventing liver damage in laparoscopic hepatic resection. [ABSTRACT FROM AUTHOR]

Dynamics of a three-dimensionally movable microflight mechanism were analyzed both theoretically and experimentally. The microflight mechanism is composed of magnetic rotational wings that rotate and generate thrust in an alternating magnetic field and a body with magnetic anisotropy that contributes to attitude control. The device consisted of 2.5-mm-long wings weighing 3.5 mg which were fabricated with MEMS technology. A wing rotational frequency of 500 Hz provided enough thrust for liftoff. Experimental data obtained through high-speed camera images show good agreement with theory and also quantify the magnetic anisotropy of the microflight mechanism, which cannot be estimated theoretically. Simultaneous actuation and attitude control by an external magnetic field presented herein, which culminated in simplification and small weight of the device and thus the successful flight, is applicable to other MEMS devices. [733] Index Terms--Alternating magnetic field, attitude control, magnetic anisotropic torque, microflight, rotational wings.