This paper presents development of an optical MEMS mirror device and an application to low coherence interferometry. This device can vibrate ±0.9μm along Z-axis under resonant frequency (5.24Vpp, 28.48kHz) for lock-in detection, and can tilt to X, Y bi-direction (Optical angle X:±10.6°/±10mA, Y:±5.2°/±10mA) for 2-D scanning and optical axis alignment by electromagnetic force between planar coils and a permanent magnet. In addition, developed MEMS mirror is embedded to a time-domain low coherent interferometer with a super luminescent diode (λc: 832nm, Δλ: 14.7nm) for optical axis alignment and lock-in detection, and the thickness and refractive index of a glass plate have been evaluated with low noise.

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We have designed a novel microfluidic dispensing device using automatic droplet transportation on a wettability gradient surface that is sequentially followed by electrowetting-based liquid handling. While a droplet moves along the wettability gradient in a main channel, a portion of the droplet is drawn into a side channel and stored in a reservoir temporarily. Next, the stored liquid is dispensed into a mixing channel when a voltage is applied between two electrodes. The fabricated device succeeded in dispensing two liquids of different nanoscale volumes after extracting them from a microscale volume droplet.

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We present the theoretical analysis of a novel mechanical-contact-based submicron-Si-waveguide optical switch. The switch is composed of an identical input and output waveguides, and a movable waveguide driven by a miniature electrostatic comb actuator. The movable waveguide closes the gap between input and output waveguides. Due to mechanical-contact of submicron-Si-waveguides, input light propagates from input waveguide to output waveguide through the movable waveguide. The switch uses a transverse-electric-like polarized single-mode light at 1.55 μm telecommunication wavelength as the incident light. Theoretical calculations suggest that the optical switch with contact-tip waveguides at 45° tip angle can realize very sharp output signal change. As a result, 97.0 % transmission at the on state and 0.2 % transmission at the off state, corresponding to approximately 96.8 % optical output signal change between on and off states, are theoretically achieved by a displacement of 400 nm. Possible fabrication imperfections are estimated and their effects on the optical performance are calculated. Enlargement of all contact-tip surfaces is understood to be a promising approach for the switch performance enhancement against possible fabrication imperfections.

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The design, fabrication packaging and evaluation of a two-axis quartz MEMS-based capacitive tilt sensor is described. Two same sensing elements are microfabricated using bulk anisotropic wet etching technique on one quartz chip. Sensing element 1 detects the tilt angle around Y axis giving the output θ and sensing element 2 detects the information of Y axis and X axis, giving output γ. Microfabrication efforts are made on wet etching high aspect ratio gap between comb electrodes, good metal step coverage on the side wall of comb electrodes, and patterning surface leading wire and pads. The sensor is mounted on a designed ceramic package by flip chip method. A special spring structure is inserted between the two sensing elements for absorbing the residual stress caused by reflow process. The sensitivity of the fabricated sensor is evaluated using diode bridge capacitance detection circuit. In the range of ±1°, voltage outputs are 529 mV/° for sensing element 1 and 394 mV/° for sensing element 2 respectively. The detection accuracy of 0.001° was also examined.

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We have investigated the novel debris-free in-air laser dicing technology for glass. The target wafer was a soda lime glass and a Pyrex glass with the thickness of 1 mm. Our technology combines two processes, which was a dicing guide fabrication and a wafer separation process. First process was the internal transformation using a fundamental wavelength of a Ti:Sapphire laser or a Nd:YAG laser. The pulse width of each laser was 100 fs and 10 ns. The threshold energy for the internal transformation (NA-0.7 focusing) was 3 μJ and 65 μJ, respectively. The second process was a thermally-induced crack propagation using CO₂ laser or a mechanical bending separation by pressing a blade. The internal transformation fabricated in first process worked sufficiently as the guide of separation, the dicing line completely followed the internal transformation. The diced cross-section was sharp and free from chipping. In addition, neither debris nor damages were found on the surface after laser dicing.

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Polyisobutylene (PIB) polymer and methylphenylsiloxane (25%) diphenylsiloxane (75%) copolymer (OV25) were coated on Quartz Crystal Microbalance (QCM) sensors and used in recognition of bread key odorants. Representative compounds of key roasty odorants of bread were taken as 3-acetylpyridine and benzaldehyde, and representative key fatty odorants were hexanal and (E)-2-nonenal. Both OV25- and PIB-coated QCM fabricated sensors could detect concentration as low as 0.9 ppm of 3-acetylpyridine and 1.2 ppm of (E)-2-nonenal. The sensitivity to 3-acetylpyridine of the OV25-coated QCM was about 1000 times higher than that of ethanol, the major interference compound in bread key odorant analysis. Further, the OV25-coated QCM response was 5-6 times and 2-3 times larger than that of the PIB-coated QCM when exposed to roasty odorants and to fatty odorants, respectively. The difference in sensitivity of the OV25- and PIB-coated QCMs we fabricated made possible to discriminate roasty from fatty odorants as was evidenced by the odor recognition map representing the frequency shifts of the OV25-coated QCM against the frequency shift of the PIB-coated QCM. In conclusion, we found that the combination of an OV25-coated QCM and a PIB-coated QCM was successful in discriminating roasty odorants from fatty odorants at the ppm level.

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The concept of a capacitive MOSFET sensor using a SOI wafer for detecting vertical force applied to its floating gate was already reported by the authors. A MOSFET is fabricated on a SOI wafer, and the box oxide under the gate is removed to release the gate structure. This sensor detects the displacement of the movable gate electrode from changes in drain current, and this current can be amplified electrically by adding voltage to the gate, i.e., the MOSFET itself serves as a mechanical sensor structure. Following this, the present paper reports the fabrication of a practical test device and its preliminary characterization. The present paper also proposes a circuitry, which converts the drain current change to the voltage change while compensating the temperature change. The performance of this circuitry is confirmed by SPICE simulation. In accelerometer application, a comparatively heavy proof mass and thin supporting beams are necessary for increasing the sensitivity. For this purpose, a fabrication process of depositing a thick mass structure using electroplating is newly proposed.

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