Recently many researches have paid attention to the role of the epidermal ridges in tactile sensitivity enhancement. In our previous and current research, we investigated the optimal structure of the ridges for sensitivity enhancement while force detection, especially the shear force detection in this article. We developed a micro-scale tactile sensor mainly by mimicking the structure of human epidermal ridge, and the parameters of proposed tactile sensor were confirmed theoretically and experimentally. By conducting series of FEM simulations and experiments, we confirmed that the proposed tactile sensor is reliable and effective to achieve an enhanced sensitivity when the ridge height is 160 μm, which is 3 times of the results obtained without ridges.

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We have proposed a novel micro-calorimetric hydrogen sensor based on the temperature difference detection due to the exothermic reaction caused by hydrogen absorption in the palladium (Pd) thin film as a hydrogen absorbing material, and demonstrated using the prototype hydrogen sensor with a microheater and a pair of cantilever SOI thermocouples that this H₂ sensor by this proposed mechanism is surely possible. We have ascertained that the sensor output voltage is increased as the H₂ concentration is increased, that the exothermic reaction ceases after finish of the hydrogen absorption, the exothermic reaction by hydrogen absorption occurs even in pure N₂ gas, that larger output voltage is observed for lower ambient temperature even under no oxygen gas, and that this hydrogen sensor does not respond to the CH₄ gas. We have found that the detection of H₂ concentration based on the exothermic reaction is preferred to carried out after heating the sensing region rather than during heating it especially in lower H₂ concentration than about 5 vol.%, because we can use the null method to detect the extremely low H₂ concentration.

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This paper reports the observation of winking phenomenon in a ring laser gyroscope (RLG), in which the air is used as a laser path with a semiconductor optical amplifier (SOA) as a gain medium. The winking phenomenon is a significant characteristic of RLGs, which the light intensity varies with an applied angular velocity. The ring laser resonator using an SOA was assembled to observe the winking phenomenon and resonance characteristics were examined. As a result, the winking phenomenon was successfully observed and we found that the SOA can be used for the gain medium of the RLG.

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We experimentally demonstrated the differences of surface modification effects on silicon-based polymer of soft-type silicone-rubber and hard-type silicone-resin in contact angle and bonding strength by exposure of oxygen plasma, atmospheric pressure plasma, and vacuum-ultraviolet light, in order to investigate the availability of non-vacuum process of atmospheric plasma and vacuum-ultraviolet light for high-throughput surface modifications and bonding. We also propose the use of a hard silicone-resin for Micro Electro Mechanical Systems (MEMS) and Micro-Total Analysis Systems (μ-TAS) material to overcome drawbacks of silicone-rubber, such as easy deformation and destruction of micro / nano structures caused by its softness. As a result, any modification method successfully modified the surface of both silicone-rubber and silicone-resin up to about 10° in contact angle, and bonded to glass. However, the bonding strength between silicone-resin and glass by vacuum ultraviolet light was one order of magnitude smaller than that by oxygen plasma and atmospheric plasma bonding. The results suggest that atmospheric plasma satisfies both high-speed non-vacuum process and high-efficient way for surface modification and the following bonding.

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