This paper represents a review of recent microactuator technologies. The problems and potentials of scaling actuators down to microscopic scale are first discussed from two points of view. One is based on scale rules; several examples of driving forces and structures suitable for miniaturization are examined. A great potential of microactuators as communication devices is also discussed. Recent R&D activities on microactuators are reviewed. These include electromagnetic, electrostatic, piezoelectric, shape memory alloy, polymer gel, light-driven, giant magnetrostrictive, pneumatic, hydraulic, and muscle-like actuators.

View full abstract

This paper describes Electrostatic Controlled Linear Inchworm Actuator (ECLIA) for advanced positioning. Besides accuracy, large stroke motion and high throughput become important to improve positioning efficiency. This paper presents ECLIA that can provide high accuracy (nm order) due to a piezoactuation, large stroke (mm order) through an inchworm motion, and high throughput of parallel motion of several actuators. Furthermore, vertical motion type of ECLIA is also designed and presented. Design, implementation and demonstration of a variety of ECLIA will be reported.

View full abstract

A responsive microthermocouple probe with a time constant of 2-3 ms was constructed using a fabrication method for glass microelectrodes as widely utilized in neurobiology. The probe is composed of a constantan wire of 25 μm in diameter and a vapor-deposited copper film of 1.8 μm in thickness. These two components come into contact at the tip of a glass pipette, forming a sensing junction of approximately 17 μm in diameter. The thermoelectromotive force of 40.2 μV/°C is very close to the standard value of the International Electrotechnical Commission and linearly dependent on temperature over the range normally encountered in biological measurement. The microthermocouple probe was tested by insertion into a dorsal longitudinal muscle of a silkworm moth. The core temperature was found to rise rapidly by 10-11 °C after pheromonal stimulation, returning to the original temperature at rest in 15-20 min. Moreover, the probe was used successfully to measure the temperature variation in the thorax of a cockroach without damage to the tissue.

View full abstract

This paper presents a chain motion by a serial microactuator in the following view points: 1) Design of a microactuator providing a large displacement; 2) Concept of a mechatronics relay transmitting both electrical and mechanical signals. A serial microactuator composed of four sets of comb structures was designed and fabricated on SOI substrate to confirm a proposed motion. Experimental results on a chain motion of a serial microactuator will be reported in this paper.

View full abstract

In this paper, electrical and optical characteristics of single artificial lipid membrane for basic taste solutions were examined. These characteristics were measured as follows; 1) Electrical characteristic: capacitance and conductance with frequency change, 2) Optical characteristic: optical transmittance with time response. Furthermore, based on the characteristics, we drew the taste response patterns of six-axis radar chart. As a result, the response patterns showed the different shape among the basic taste solutions.

View full abstract