The shape memory alloys (SMAs) are known to exhibit shape memory effect and super elasticity. Thus far, micro electro mechanical systems (MEMS) devices and micro actuator using shape memory effect were developed. Recently, the super elasticity and electrocaloric effect are attracted, some microdevices using those effect have already been reported. In this review, the recent progress in the MEMS field of the SMAs was described.

In this paper, we report on the fabrication and evaluation of actuator for reaction force variable passive-type tactile display using high formable Ti-Ni-Cu shape memory alloy. This actuator is driven by the superelastic effect and superior in force expression, responsiveness, and miniaturization compared to conventional tactile displays using shape memory alloys. This actuator was fabricated in a convex shape by utilizing a viscous flow of Ti-Ni-Cu metallic glass. After crystallization, the metallic glass was changed to the shape memory alloy. In this manner, we successfully acquired the desired convex cross structure with a height of 123 µm at the center of cross. Additionally, while pushing 100 µm, we successfully varied the reaction force ranged from 40 to 80 mN, necessary to deform the skin and electrical resistance linearly by controlling the temperature. From these results, we showed that the actuator of this study can be used as tactile display that can express desired hardness and softness by temperature control. We also showed the possibility that the temperature of each actuator can be controlled individually by electrical heating using the linear relationship between temperature and electrical resistance.

Nano Co-metal doped carbon powder could be prepared by a carbon-combustion method using large surface area carbon loaded with Co-nitrate. The Co-carbon thick-film sensor prepared by screen printing method showed relatively good response of potentiometric sensing to hydrogen-phosphate ion in the concentration range between 3.0×10^-4 M and 1.0×10^-2 M at pH=5 with high selectivity among the tested anions; NO₃^-, Cl^-, Br^-, HCO₃^-, and CH₃COO^-. The 90% response time of the sensor device was as short as about 3 min at room temperature.

Non-invasive Positive Pressure Ventilation (NPPV), an artificial respiration therapy, is a treatment that attaches a mask to the patient’s face and delivers gas into the mask to support breathing. The NPPV mask straps are tensioned so that the supplied gas in the mask does not leak. However, leakage of the gas occurs when the mask strap tension is unbalanced or too weak, while ulcers are caused when the tension is too strong. However, there has been no technical method to know the strength and the balance of the strap tensions quantitatively in NPPV mask fitting.

In this study, we focus on the mask strap tension, and fabricated a system for measuring the mask strap loads using thin film force sensors. In order to grasp the balance of the mask strap load applied to the mask body, the center point of a distributed load (balance point) is calculated, and a real-time coordinate image is displayed on the system. Finding the distance from the ideal balance point, it is possible to fit the mask properly in consideration of the strap balance. This system is effective to measure the mask balance quantitatively, and it can be used to improve the mask fitting condition.

The widespread of near-infrared spectroscopes in the consumer field is expected to create new demand, such as the detections of fruit and vegetable rot and the easy measurement of the amount of water in the skin. Conventional cooled photodiodes using compound semiconductor materials such as InGaAs have problems with cost reduction and miniaturization. Therefore, we proposed an electrostatic Si microresonator device for the realization of a near-infrared optical sensor. This device measures the resonance frequency shift caused by the thermal stress generated in the resonator due to light absorption depending on the light intensity. The purpose of this study is to apply the device to near-infrared spectroscopy of water as a photodetector. We proposed an evaluation method based on a theoretical equation and confirmed that the device could detect the near-infrared absorption spectrum of water. The measurement results of the developed device matched well with that of the commercially available photodiode intensity sensor. In the future, it is expected that a compact near-infrared spectrometer with high sensitivity and low cost will be realized by arranging devices that integrate absorbers with different wavelength dependencies.