Electroactive polymer transducers have many features that are desirable for MEMS devices. An especially attractive type of electroactive polymer is dielectric elastomer. Dielectric elastomers, transducers that couple the deformation of a rubbery polymer film to an applied electric field, show particular promise with features such as simple fabrication in a variety of size scales, high strain and energy density, high efficiency and fast speed of response, and inherent flexibility, environmental tolerance, and ruggedness. A variety of actuator configurations has been demonstrated at the small size scales needed for MEMS devices, including rolled “artificial muscle" actuators, framed and bending beam actuators for efficient opto-mechanical switches, and diaphragm and thickness mode actuators for pumps and valves. The performance benefits of electroactive polymers can allow for new generations of devices in microrobotics, communications, and biotechnology. Several challenges remain for electroactive polymers, including microfabrication, integration with driving electronics, and operational lifetime.

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Voice recognition utilizing bone-conducted voice, which is very robust under noisy environment, has been investigated. The suitability for voice recognition and voice communication of bone-conducted voice recorded at several measurement points on human head was evaluated using LPC cepstrum distance (LCD) and Speech Transmission Index (STI). Experimental results show that forehead and cheek are good as the acquisition points of bone-conducted voice. In order to improve the quality of bone-conducted voice, a novel sensor, which has an inclined frequency response, was fabricated. Using the sensor, acquired bone-conducted voice has a similar frequency response as that of air-conducted voice. Spectral Subtraction is suggested as a method to improve the voice recognition ratio of bone-conducted voice.

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The dual-stage positioning system technology for hard disk drives is one of the most important technologies for the fast and precise positioning of the magnetic head and the wide servo bandwidth. This paper describes a prototype of the electromagnetic micro actuator for dual-stage positioning. It is composed of a movable part with a yoke supported by the cross-shaped spring and the four micro coils. The driving force of this actuator is the electromagnetic force generated by those coils. The displacement was 3.2 μm at the frequency of 2 kHz with the applied voltage of 2.1 V. The linearity between the coil current and the displacement was fairly good by the differential current driving method. The first and second resonant frequency were 580 Hz and 20 kHz respectively.

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The device for controlling the temperature locally under a microscope in a short response time, within 3 seconds, is developed. This device is equipped with a temperature controlling micro heater and a micro thermo sensor patterned on a glass plate which can be used for general biochemical assay. Since this device controls the temperature so locally, the total amount of the heat which is needed for temperature controlling is small enough to avoid the negative effects such as defocusing during observation under a microscope. We established the sensor model to calculate the temperature from the measured resistance value and the initial resistance at the roon temperature. Thus, we can avoid the calibration in each sensor. The rotation velocity change of a single F1 molecule, the rotary biomolecular motor, within short response time is successfully observed by controlling the temperature. This is the result that could not be achieved without MEMS technology. This result also shows the applicability of the device to other temperature controlling biochemical assay.

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It is very important to monitor the actual condition of automobile engine oil. We propose a multi-information monitoring system of engine oil degradation for obtaining the information of the transparency, temperature and dielectric constant of the engine oil at the same time. In our research, we measure degradation extent of engine oil by using a photo-diode and Light Emitting Diode (LED). First, we measure the transparency and temperature of the engine oil by the capacitance between the two terminals of the photo-diode, second, the dielectric constant of the engine oil is measured by the capacitance between the photo-diode and outer shell of LED. Our measurement method is characterized by measuring the capacitance between two terminals of photo-diode and regarding the outer shell as an electrode of the capacitor. Experimental results show the feasibility of measuring the degradation extent of engine oil with this method.

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