Recently, research and development of the micro-fluidic systems such as μTAS and Lab-on-chip have been activated in the field of chemical technology and biotechnology. Micro-fluidic systems are realized by micromachine technology and MEMS technology. These are essential elements for miniaturization of chemical analysis reaction systems. Furthermore, micro-fluidic systems can be applied to home medical care system. Micro mixing device is an essential element for a realization of these systems. Normally, mixing of different fluids depends on turbulent flow and diffusion. But it is difficult to generate turbulent flow in minute space. Micro mixer is important to improve reaction efficiency. The aim of this research is a development of a micro rotary reactor which will be built into micro-fluidic systems. The full length and the diameter of this reactor are 59mm and 15mm, respectively. This reactor is driven by an electromagnetic actuator. Therefore, the structure of this reactor becomes very simple and it is easy to miniaturize this reactor. This reactor aims at combing two liquids and forming spiral laminar flow interfaces. Forming spiral laminar flow interfaces increase reaction surface area and reaction distance of two liquids. This paper shows the structure and the characteristics of this reactor.

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The aim of this paper is development of micro lancet needle made of biodegradable polymer (Poly Lactic Acid, called as PLA). This device is applicable to a blood test system for diabetics. Since PLA naturally degrades itself in tissues, this material is safe for human body. To achieve the purpose of this study, we focused on wet chemical anisotropic etching process of silicon negative groove, and micromolding process of PLA. Resistance force during inserting a fabricated needle to an artificial skin of silicone rubber is investigated experimentally. The effects of thinning needle, sharpening tip, vibrating it during insertion, pitching out the inserted object surface, etc., for decreasing the resistance force are confirmed.

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We have developed a microdevice for cellular analysis, which has a microwell for cell culture and on-chip microvalves for sample injection. In order to reduce dead volume in the sample injector, the device structure is designed to minimize distance between the microwell and the sample injector. Two types of PDMS are used for the lid of the microdevice and the diaphragm of the microvalves, which have an advantage of high transparency and that of bio-compatibility, respectively. Mechanical property and gas permeability of the two types of PDMS are examined and the results show that the both PDMS are applicable to the microdevice. Using the fabricated prototype device, sample injection of the order of nano-liter is demonstrated successfully.

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In this research, an ultrasonic probe (5.5 mm in diameter), which has a concave PZT transducer at its tip, was fabricated for ultrasonic treatments such as sonoporation and sonodynamic therapy in the human body using a catheter and/or endoscope. Ultrasound has the potential to enhance cytotoxicity of drugs such as porphyrins, a process referred to as sonodynamic therapy, and also to deliver macromolecules such as plasmid DNA, a process referred to as sonoporation. The fabricated probe was then experimentally characterized by measuring the acoustic intensity distribution around the focal point, using a PVDF needle-type ultrasonic hydrophone. When the PZT transducer was driven by a 120 Volts peak-to-peak AC signal at 1.83 MHz, the ultrasound output was successfully focused at the focal point, with a peak intensity of 24.9 W/cm² (0.87 MPa). Using the fabricated probe, cultured Chinese Hamster Ovary (CHO) cells were exposed to ultrasound (1.83 MHz, continuous wave, peak acoustic pressure of 0.5 MPa) for 2 s in the presence of microbubbles MB-3 and Green Fluorescent Protein (GFP) plasmid DNA. As a result of sonication, the expression of GFP was observed in CHO cells.

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Bending motions of the tip of a conventional endoscope are controlled from outside the body by wire traction. A shaft of an endoscope should be relatively hard to avoid buckling by wire traction. Therefore, precise operation of the endoscope is difficult in complex shape areas such as the intestine. Furthermore, patients suffer pain during a procedure with an endoscope. An active bending electric endoscope using shape memory alloy (SMA) actuators has been developed. A CCD camera (410,000 pixels) is mounted at the end of the endoscope and the tip has an omni-directional bending mechanism using three SMA coil actuators. The SMA coil actuators contract by supplying electrical current and bend the endoscope. The external diameter of the fabricated endoscope is 5.5 mm. The maximum bending angle of the fabricated endoscope is 90° (Curvature radius: 29 mm). The observation of the inside of a blood vessel model by the CCD imager of a fabricated endoscope was confirmed. The active bending shaft of the fabricated endoscope, which is realized using SMA coil actuators instead of wire traction, is soft. Therefore, using this endoscope, it may be possible to perform precise observations and treatment of deep areas of the human body.

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We proposed a new method of patterning a chemically adsorbed monomolecular layer on the substrate and then dropping UV cure material to form a lens shape using oil repellent effect of this film. The curvature radius of the lens was controlled by the amount of the dropped UV cure material. Using this method, a micro-lens array of various radiuses was fabricated. The formed micro-lens array shapes are transferred by the electro-plating and then the micro dies are fabricated, which are used for molding the plastic lens array. The optical characteristic of the molded micro-lens was evaluated.

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A human face identification system based on isodensity maps has been already proposed by authers. The isodensity maps are contours of isodensity areas, therefore they can be easily transformed into a chain code. By using chain-coded isodensity contours, improvement of the processing performance can be expected in terms of the processing time and the data size required.
When the isodensity contours are expressed by chain codes, however, the chain codes corresponding to one isodensity area are occasionally divided into several parts by only using a simple encoding scheme.
Consequently, in this paper, a new chain encoding method which is adequate for extracting isodensity contours is presented.

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Pressure sensors using polycrystalline diamond can operate at a high temperature. However, the sensors usually have a very low Gauge Factor (G.F.), less than 100 and the special process is required to improve the sensitivity. In order to obtain a high G.F. without the special fabrication process, the combination of scratch and spin coat seeding methods have been introduced. By using the proposed method, it was possible to grow the diamond film uniformly on a SiO₂ substrate and the adhesion force of the film to the substrate increased up to 900 N/cm² at the maximum value. Boron doped diamond films were deposited on a Si diaphragm using the developed method in a fabrication process of a pressure sensor. Although the sensor demonstrated a good linearity in the pressure response, the G.F. was only 29 because of the poor surface conduction. To improve the surface conduction, the oxygen termination of the surface and relaxation of hydrogen defect by annealing were introduced respectively. As a result, the G.F. was improved up to 168. Oxidization by hot mixed acid also improved the G.F. to 285. The sensor treated by this oxidization showed the better uniformity in the temperature characteristic.

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Dependence of elastic modulus of micro cantilever fabricated by micro-stereolithography (μSL) on irradiation laser power is investigated in this study. The samples are formed by changing the irradiation laser power of μSL system and postcure processing time. A device for measuring deflection of the micro cantilever and applied load is developed. Then, the elastic moduli of the samples are evaluated from the gradient of the measured load-deflection relation and the formula of the strength of materials. Results show that the elastic modulus of the micro cantilever made by μSL is depend on the irradiation laser power. That is, the mechanical property of micro structures can be controlled by the irradiation laser power and post cure process.

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