In this study, the flame temperature is visualized in a newly designed optical access diesel engine in order to investigate the mechanism of soot emission at transient operation mode. This single cylinder diesel engine has hydraulic variable valve system and an optical access window instead of an exhaust valve. Optical access window has cleaned by the laser cleaning technique in which the soot on the window is vaporized by the Nd:YAG laser incident. Using this optical engine, high speed photographs of flame were taken under transient operation, and flame temperature was analyzed by two color pyrometry.

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A microelectromechanical systems (MEMS) combined sensor measuring two-axis accelerations and an angular rate (rotation) has been developed for an electronic stability control system of automobiles. With the recent trend to mount the combined sensors in the engine compartment, the operation temperature range increased drastically, with the request of immunity to environmental disturbances such as vibration. In this paper, we report the combined sensor which has a gyroscopic part and two acceleration parts in single die. A deformation-robust MEMS structure has been adopted to achieve stable operation under wide temperature range (-40 to 125°C) in the engine compartment. A package as small as 10 × 19 × 4 mm is achieved by adopting TSV (through silicon via) and WLP (wafer-level package) technologies with enough performance as automotive grade.

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Photonic crystal is a key component for optical communication and computing in next generation that having a periodic 3D structure in scale with optical wave length. The major difficulty in practical use of photonic crystal exists in its fabrication process. As an optical component, it must be a defect-free large crystal with waveguide patterns affecting propagation of photons. Many attempts have been made to realize such a crystal, however, low-cost and rapid fabrication of a defect-free large crystal is still a difficult problem. Here, we propose a novel fabrication method combining colloidal crystallization and DNA nanotechnology. In this method, the face-centered lattice made of 1µ m polystyrene particle is assembled on a patterned template in a layer-by-layer fashion. In order to control the binding among particles, DNA-gold nanoparticle conjugates (10nm GNP modified with 52-mer DNA) is used. Specific bonding rules between particles and GNPs defined by base sequence of DNA realizes the layer-by-layer growth of the crystal. We have built two-layer crystal by the proposed method and the results show its feasibility. We also found some important factors necessary to improve the quality of the crystal.

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An excellent cavity ring-down spectroanalyzer was realized using a reflective semiconductor optical amplifier. A negative feedback optical amplification effect of the amplifier recovers signal loss to a higher definition and provides an output signal whose baseline was reduced optically. A sample cell was formed to meet fibers in the face. 0.5% - 16% saccharose solutions were analyzed by the spectroanalyzer with 1512 nm leaser.

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We propose a new processing method to form polymeric thin films on defined areas of movable parts of microdevices by using trench frames on the device surfaces. We fabricated additional surficial trench frames on silicon microcantilevers to define the areas coated with the polymeric films by increasing the tolerance to protrusion of a liquid droplet from the edge in the coating process. The 500 nm-wide trench frames were fabricated on the silicon surfaces by deep-reactive ion etching process with the resist mask patterned by electron beam lithography. We also fabricated the same trench frames on planer silicon substrates, and we formed polybutadiene (PBD) thin films on the surfaces using a microdispenser system. When the n-dodecane solution of PBD was coated on the micro-area framed by the trenches, PBD film was successfully defined within the framed area. The trench frames fabricated on the cantilevers also indicated the possible effectiveness to define the coated PBD films in the framed areas.

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We have developed a network type tactile sensor system, which realizes high-density tactile sensors on the whole-body of nursing and communication robots. The system consists of three kinds of nodes: host, relay and sensor nodes. Roles of the sensor node are to sense forces and, to encode the sensing data and to transmit the encoded data on serial channels by interruption handling. Relay nodes and host deal with a number of the encoded sensing data from the sensor nodes. A sensor node consists of a capacitive MEMS force sensor and a signal processing/transmission LSI. In this paper, details of an LSI for the sensor node are described. We designed experimental sensor node LSI chips by a commercial 0.18µm standard CMOS process. The 0.18µm LSIs were supplied in wafer level for MEMS post-process. The LSI chip area is 2.4mm × 2.4mm, which includes logic, CF converter and memory circuits. The maximum clock frequency of the chip with a large capacitive load is 10MHz. Measured power consumption at 10MHz clock is 2.23mW. Experimental results indicate that size, response time, sensor sensitivity and power consumption are all enough for practical tactile sensor systems.

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Silicon-on-insulator (SOI) wafers are used for many micro-electro-mechanical systems (MEMS). The influences of residual stress of SOI wafer on the fabricated structures are important especially for micro-mirror because the optical performances are often affected by them. In this study, we propose an analytical calculation for the deformation of mirror and frame of a varifocal mirror. The deformations of the fabricated structures were measured using a white light interferometer. The frame was tilted at 2.8mrad which was explained by the calculated value of 3.9mrad. The mirror was deflected by 100nm with the top-flat shape, which also agreed well with the proposed analysis.

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