The proposed application of magnetic sensors can be divided into those related to the direct measurement of very weak magnetic field, e.g., the biomagnetic field such as that of a magnetocardiogram (MCG), and those related to the measurement of other quantities by means of variations in the magnetic field, e.g., the force sensor used in automobiles and industrial robots. With this in mind, it is necessary to develop a highly sensitive magnetic sensor. In constructing such a highly sensitive magnetic sensor, the present authors have been studying the fabrication of bulk Bi-Pb-Sr-Ca-Cu-O (BPSCCO) as the magnetic sensor. This process makes use of the shock compaction method as a new fabrication technology of the bulk high-critical temperature superconductor (HTS). In the present paper, the criterion for fabricating a highly sensitive magnetic sensor is discussed when systematically changing the sensor thickness between 0.1 and 1.1 mm for sensors fabricated under a shock compaction pressure of 1 GPa. The magnetic sensitivity is found to be related to the value of thickness, and reached an approximate sensitivity value sensitivity of 400 %/(10^-4 T) for the sensor with the thickness of 0.1 mm, being about 400 times that of a giant magnetoresitance (GMR) sensor. Experimental results revealed the dependencies of the sensitivity on sensor thickness, shock compaction pressure, and different BPSCCO particle size distributions. In addition, the present authors examined the voltage noise power (VNP) spectrum in order to clarify the voltage fluctuations of the magnetic sensors.

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This paper describes the formation of fluidic channels by surface adhesion control of the patterned perfluoro polymer layer. We proposed release technology using the poor adhesive region formed by the patterned perfluoro polymer layer. Proposed method releases layered films so as to form a space for a channel. It is possible to close the channel completely because the layered films are contacted together in the initial state. This feature allows leakless micro diaphragm valves and thinner balloon devices. On the other hand, the patterning process of the perfluoro polymer layer without the increase of adhesiveness is necessary in order to realize proposed release technology, because the surface propeties of the perfluoro polymer are sensitive to the conditions of patterning process. Our group obtained successful results of the proposed release technology by the use of copper as a dry eching mask with post-annealing at temperatures higher than the glass transition temperature.

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In this paper, we proposed a sealing technique for sealing a glass cap with a ceramic substrate by using silica coating liquid to increase the performance of fluid-based inclination sensor in durability and heat-resisting properties. The diameter of glass cap and height were 4.0 mm and 2.0 mm, respectively. The sensor was developed with one-side-electrode-type structure and propylene carbonate was used as electrolyte. The sensor uses capacitance change to detect the angle of inclination, and it is capable of measuring inclination at the supply voltage of 1.5 V when the sensor is combined with the capacitance detection circuitry. The current consumption of inclination sensor was decreased from 250 μA to 49.3 μA by replacing an operational amplifier to an inverter amplifier in the capacitance detection circuitry. The sensitivity, response time and resolution of sensor were 4 mV/deg, 0.6 s and 1.8°, respectively at supply voltage of 1.5 V. The temperature characteristic of sensor was evaluated between -10°C to 50°C.

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This paper presents an improved infrared position sensitive detector (IRPSD) that is operated in a vacuum condition. IRPSD is a two-dimensional infrared array sensor with two thermometers in each pixel. One thermometer is serially connected in a row and the other is serially connected in a column. The serial connection of these thermometers produces the sum of signals from all pixels in each row and column. With this array architecture, IRPSD extracts specific information without digital image processing. In this study, we developed an IRPSD that uses thermopiles as thermometers. To achieve high responsivity and large signal-to-noise ratio, we optimized the pattern layout of the pixel, considering thermal conductance and Johnson noise. As a result, responsivity of about 170 V/W was obtained.

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A terahertz chemical microscope (TCM) has been developed to visualize the chemical concentration of solutions in fluidic chips. Chemical potential — terahertz transducers were newly developed and applied to the bottom surfaces of the flow channels. When femtosecond laser pulses hit the transducers, terahertz waves are radiated from them. Since the amplitude of terahertz waves can be related to the chemical potential on the surface of the device, the distribution of chemical reactions on the surface can be visualized by scanning the laser on the device. Here, we report the demonstration of mapping of pH values using TCM with a spatial resolution of less than 1 mm. The pH distribution of the flow channels filled with 0.01 M NaOH and HCl was successfully visualized. In addition, the neutralization process was monitored.

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