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Showing papers in "Ieej Transactions on Sensors and Micromachines in 2004"



Journal ArticleDOI
TL;DR: The bioelectric potential of a foliage plant changes according to an occupant's behavior, for example entering the room in which the plant is installed, as well as watering and touching the plant as mentioned in this paper.
Abstract: The bioelectric potential of a foliage plant changes according to an occupant’s behavior, for example entering the room in which the plant is installed, as well as watering and touching the plant The potential shows the impulse responses due to the behaviors In this study, the integrated values of the bioelectric potential were adopted to identify those behaviors There are two types of values Those were derived by integrating the bioelectric potential characteristics for a minute (vm1) and for an hour (vh1) respectively The histogram of the values vm1 for the steady state perfectly took a normal distribution The frequencies of vm1 for the behaviors were different compared with the steady state distribution The system can identify the behaviors by examining the frequency table of vm1 Conversely, it is thought the plant gives us some suggestions using bioelectric potential characteristics A clue for communication between humans and plants was also obtained The vh1 becomes higher as the average room temperature (tr) becomes lower There was a negative correlation between vm1 and tr There were two groups in the scatter diagram of the variables vm1 and tr

14 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a new concept for anisotropic single crystalline silicon (Si) etching simulation, which combines three calculation modules, a molecular dynamics calculation module to define chemical reaction probability, a cellular-automata module to calculate etching rate, and a Wulff-Jaccodine graphical method module to predict an etched shape.
Abstract: We propose a new concept for anisotropic single crystalline silicon (Si) etching simulation. Our approach combines three calculation modules, a molecular dynamics calculation module to define chemical reaction probability, a Cellular-Automaton module to calculate etching rate, and a Wulff-Jaccodine graphical method module to predict an etched shape. This configuration allows mm scale process simulation based on atomic scale physical chemistry of anisotropic Si etching. In this paper, the performance of a newly developed Cellular-Automata module, called CAES (Cellular-Automata Etching simulator), is presented as a first step towards the realization of our simulation concept.

10 citations


Journal ArticleDOI
TL;DR: In this article, a variety of actuator configurations have been demonstrated at the small size scales needed for MEMS devices, including rolled artificial muscle actuators, framed and bending beam actuators for efficient opto-mechanical switches, and diaphragm and thickness mode actuators.
Abstract: Electroactive polymer transducers have many features that are desirable for MEMS devices. An especially attractive type of electroactive polymer is dielectric elastomer. Dielectric elastomers, transducers that couple the deformation of a rubbery polymer film to an applied electric field, show particular promise with features such as simple fabrication in a variety of size scales, high strain and energy density, high efficiency and fast speed of response, and inherent flexibility, environmental tolerance, and ruggedness. A variety of actuator configurations has been demonstrated at the small size scales needed for MEMS devices, including rolled “artificial muscle" actuators, framed and bending beam actuators for efficient opto-mechanical switches, and diaphragm and thickness mode actuators for pumps and valves. The performance benefits of electroactive polymers can allow for new generations of devices in microrobotics, communications, and biotechnology. Several challenges remain for electroactive polymers, including microfabrication, integration with driving electronics, and operational lifetime.

10 citations


Journal ArticleDOI
TL;DR: In this paper, a thin glass substrate was plastered over with SU-8 and UV light was irradiated through the glass substrate, and three dimensional structures such as micro capillaries were fabricated on PDMS from the SU 8 structures by molding.
Abstract: Three dimensional structures on SU-8 photoresist were fabricated by gray-scale lithography. A thin glass substrate was plastered over with SU-8 and UV light was irradiated through the glass substrate. SU-8 structures with maximum 400 μm height and strong adhesion to the substrate were achieved by the lithography technique. The relation between gray-scale value and the resist height were evaluated and the maximum surface roughness of the structure was 0.98 μm. Three dimensional structures such as micro capillaries were fabricated on PDMS from the SU-8 structures by molding.

10 citations


Journal ArticleDOI
TL;DR: In this paper, the suitability for voice recognition and voice communication of bone-conducted voice recorded at several measurement points on human head was evaluated using LPC cepstrum distance (LCD) and STI.
Abstract: Voice recognition utilizing bone-conducted voice, which is very robust under noisy environment, has been investigated. The suitability for voice recognition and voice communication of bone-conducted voice recorded at several measurement points on human head was evaluated using LPC cepstrum distance (LCD) and Speech Transmission Index (STI). Experimental results show that forehead and cheek are good as the acquisition points of bone-conducted voice. In order to improve the quality of bone-conducted voice, a novel sensor, which has an inclined frequency response, was fabricated. Using the sensor, acquired bone-conducted voice has a similar frequency response as that of air-conducted voice. Spectral Subtraction is suggested as a method to improve the voice recognition ratio of bone-conducted voice.

8 citations


Journal ArticleDOI
TL;DR: In this paper, the material filling of the needle tips and dermal penetrability were evaluated and compared with the analysis of flexibility by CAE; computer aided experiment was conducted.
Abstract: We hereby fabricated the microneedle arrays whose dimensions of 300 μm in height, 100 and 150 μm in diagonal lengths of bottom surface and with densities of 900 and 4,400 needles/ cm2 by injection molding. The resist patterns were pre-formed by three-dimensional fine manufacturing with movable resist during the exposure in LIGA process. Polylactic acid was used for microneedle arrays in consideration of the prospective medical use in transdermal methods and the like. Our study was to evaluate the material filling of the needle tips and dermal penetrability. The flexibility of the needle tips was also tested by the force added to the tips, and its result was compared with the analysis of flexibility by CAE; computer aided experiment. The resin filling did not reach to the deepest point of the Ni stamper, and the filling remained within the range of 12 to 17 μm in diameter. However, the penetration rate on pig skin with the density of 900 needles / cm2 resulted in the range of 60 to 80%, and this result represented the satisfactory capability of dermal penetration in spite of the previously described needle tip dimensions of microneedle array. Closely resembling needle flexibility to its analysis proved that CAE analysis on the strength of microstructures was well effective.

8 citations



Journal ArticleDOI
TL;DR: In this article, the authors developed a simple and effective coupling method called "silicone rubber coupling method" for interconnecting modular micro fluidic devices such as "Biochemical IC Family" proposed by Ikuta.
Abstract: We developed a simple and effective coupling method “silicone rubber coupling method” for interconnecting modular micro fluidic devices such as “Biochemical IC Family” proposed by Ikuta. This coupling method utilizes thin silicone rubber films and the holder unit. The biochemical IC chips are stacked up into the holder unit. And reusable thin silicone rubber films formed by a polymer mold are sandwiched between the IC chips. This simple coupler provided a good seal under high pressure (>400 kPa). Moreover, the experiments of this method showed that the maximum leakage pressure increases while the thickness of the silicone rubber gets thin, differing from general sealing technology “O-ring”. Thin coupling part is effective in practical use. This method is useful not only for the biochemical IC chips but also other micro fluidic devices.

6 citations


Journal ArticleDOI
TL;DR: In this paper, a method for evaluating transverse piezoelectric coefficient of a thin film on a bulk substrate has been proposed, which is simple and independent on elastic constants of both the film and the substrate when the film is thinner enough than the substrate.
Abstract: A method for evaluating transverse piezoelectric coefficient of a thin film on a bulk substrate has been proposed. The measurement method is simple and independent on elastic constants of both the film and the substrate when the film is thinner enough than the substrate. Piezoelectric properties of sol-gel derived PZT (Pb(Zr, Ti)O3) thin films before and after electrical poling were evaluated using this method. The piezoelectric coefficient h31 of the film of 2.2μ thickness is -400MV/m after a poling of -200kV/cm, which is about a half of that of poled ceramic. Improvement of piezoelectric property by poling was confirmed to be caused by increase of retained polarization with clear proportionality.

6 citations


Journal ArticleDOI
TL;DR: In this article, a microsensor mounted on a chip has been developed to measure the concentration of a one drop solution, which could analyze electrolytes and amino acids. But, the form of the micro sensor was thin Cu electrodes of 12 mm2.
Abstract: Recently, bio-microelectromechanical systems (Bio MEMSs) composed of a micro pump, mixer, valve, reactor, sensor, and an electric circuit on a chip, have being applied to biological or medical analyses. A microsensor mounted on a chip has been developed to measure the concentration of a one drop solution. The form of the microsensor on a chip was thin Cu electrodes of 12 mm2. The sensing function was evaluated by the concentration measurement of a solution (100nL) dropped on the microsensor, which could analyze electrolytes and amino acids. The electric resistance of the microsensor related well to the concentration of the solution. Further, the electric resistance of the sensor was related to light intensity that was irradiated to its surface. To measure the concentration of a solution, it is necessary to irradiate light of a constant intensity on the microsensor.

Journal ArticleDOI
TL;DR: In this article, a temperature control micro heater and a micro thermo sensor patterned on a glass plate was used for general biochemical assay. But the temperature control was performed in a short response time, within 3 seconds.
Abstract: The device for controlling the temperature locally under a microscope in a short response time, within 3 seconds, is developed. This device is equipped with a temperature controlling micro heater and a micro thermo sensor patterned on a glass plate which can be used for general biochemical assay. Since this device controls the temperature so locally, the total amount of the heat which is needed for temperature controlling is small enough to avoid the negative effects such as defocusing during observation under a microscope. We established the sensor model to calculate the temperature from the measured resistance value and the initial resistance at the roon temperature. Thus, we can avoid the calibration in each sensor. The rotation velocity change of a single F1 molecule, the rotary biomolecular motor, within short response time is successfully observed by controlling the temperature. This is the result that could not be achieved without MEMS technology. This result also shows the applicability of the device to other temperature controlling biochemical assay.

Journal ArticleDOI
TL;DR: In this article, the authors have successfully developed a novel micromechanism of random number generator (RNG) by using the silicon micromachining technique, which is made by the deep reactive ion etching of a silicon-on-insulator (SOI) wafer.
Abstract: We have successfully developed a novel micromechanism of random number generator (RNG) by using the silicon micromachining technique. The MEM(Micro Electro Mechanical)RNG produce a series of random numbers by using the pull-in instability of electrostatic actuation operated with a typical dc 150 volt. The MEM RNG is made by the deep reactive ion etching of a silicon-on-insulator(SOI) wafer, and is very small compared with the conventional RNG hardware based on the randomness of thermal noise or isotope radiation. Quality of randomness has been experimentally confirmed by the self-correlation study of the generated series of numbers. The MEM RNG proposed here would be a true random number generation, which is needed for the highly secured encryption system of today’s information technology.



Journal ArticleDOI
TL;DR: In this article, a simple system for automatically and continuously measuring color change of the gas detector tube is developed, which enables real-time measurement of gas concentration change and the reduction of the read-out error.
Abstract: Although GC/MS(Gas Chromatograph/Mass Spectrum) method is often used to analyze gases, a rapid and low-cost method is required. Since a gas detector tube is well known as a simple measurement method, we focused on it to perform bad-smell sensing for monitoring living environment. We developed a simple system for automatically and continuously measuring color change of the gas detector tube. It is originally a disposable one for manually measuring the gas concentration only once at a certain time. The developed system enables the real-time measurement of the gas concentration change and the reduction of the read-out error. In the present study, we proposed the method for eliminating the influence of the noise to determine the boundary of the color-change region. The measurements of methyl mercaptan and hydrogen sulfide were reproducibly performed under the humidity-rich environment using the proposed method.

Journal ArticleDOI
TL;DR: The results show that the new high-precision speedometer development exhibits a phenomenal performance gains with low cost design, light weight and its performance provides a pragmatic element for emerging ITS infrastructure.
Abstract: In this paper, we present a new high-precision speedometer for vehicles using a K-band Doppler technology The concept of our new speedometer is based on the Doppler effects phenomenon to obtain a speed of the vehicle more precisely The experimental design, data collection and data evaluations are discussed, and the features of the new system have been appraised and compared with a conventional speedometer The results show that our new speedometer development exhibits a phenomenal performance gains with low cost design, light weight and its performance provides a pragmatic element for emerging ITS infrastructure

Journal ArticleDOI
TL;DR: In this article, a multifunctional touch-sensor based on piezoelectric ceramics was proposed to discriminate four kinds of materials such as aluminum, polymer gel, acrylic resin and silicone rubber.
Abstract: This paper describes material discrimination by means of a multifunctional touch-sensor based on piezoelectric ceramics. In the proposed sensor, the electrical property and ultrasonic characteristic of an object are measured by the proposed sensor which is contacted to the object, and the information of the object is detected from their measured values. As the experiment, discrimination of four kinds of materials such as aluminum, polymer gel, acrylic resin and silicone rubber, and detection of the thickness are demonstrated from measurements of capacitance as the electrical property and propagation time as the ultrasonic characteristic by the proposed sensor. As a result, discrimination of four kinds of materials and detection of the thickness at the range between 10mm and 40mm were possible. Therefore, the usefulness of the proposed multifunctional touch-sensor was suggested.

Journal ArticleDOI
TL;DR: In this paper, the relationship between the structure of Pt thin film and annealing temperature was discussed, and the effect of Al2O3 buffer layers was observed by secondary ion mass spectrometry (SIMS).
Abstract: High Temperature Coefficient of Resistance (TCR) platinum (Pt) thin films become increasingly attractive for devices with Micro Electro Mechanical Systems (MEMS) using high temperature. However, in annealing with high temperature, Pt thin films are degraded, and in comparison with bulk Pt, the TCR of Pt thin films are inferior. In this study, alumina (Al2O3) buffer layers were introduced between the silicon nitride (SiNx) films and Pt films. After annealing in the air, the structure of Pt thin films was observed by Scanning Electron Microscope (SEM) and analyzed by X-ray diffraction, and the depth-resolved elemental composition of interface between Pt thin films and Al2O3 buffer layers was observed by Secondary Ion Mass Spectrometry (SIMS). As the annealing temperature is higher, the grain size of Pt is larger. At the point of the largest grain size, the largest TCR could not obtain. In this paper, we discuss about the relationship between the structure of Pt thin film and annealing temperature, and about the effect of Al2O3 buffer layers.


Journal ArticleDOI
TL;DR: In this paper, the authors focus on the two types of MEMS devices, the sensor MEMS and the actuator MEMS, and report key issues of packaging for sensor and actuator devices.
Abstract: This paper reports key issues of packaging for sensor and actuator MEMS (Micro Electro Mechanical Systems) devices. In this paper, we focus on the two types of MEMS devices, the sensor MEMS and the actuator MEMS. In the case of sensor MEMS packaging, the thermal stress is the most important in order to prevent the deterioration of its sensitivity. On the other hand, in the case of actuator MEMS packaging, it is important to design the packaging for enhancing the device characteristics.

Journal ArticleDOI
TL;DR: In this article, the importance and methodology of international standardization were introduced, and the present situation of specific standardization items such as semiconductor pressure sensors, Hall elements, semiconductor accelerometers, micromachine terminology, and material evaluation methods were described.
Abstract: The importance and methodology of international standardization were introduced. The present situation of the specific standardization items such as semiconductor pressure sensors, Hall elements, semiconductor accelerometers, micromachine terminology, micromachine material evaluation methods were described.


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a new detection system for discriminating water in oil, which adopts the difference in each temperature characteristic of propagation time of an ultrasonic wave in water and in oil.
Abstract: In this paper, we propose the new detection system for discriminating water in oil. The detection method adopts the difference in each temperature characteristic of propagation time of an ultrasonic wave in water and in oil. When water and oil are heated, those propagation times show a completely reverse change. For this reason, this detection system does not need to provide any previous absolute value database as references. We tried to detect the water in the electric oil transformer container. By this experiment result, we found the possibility of discrimination of water in oil, by using the proposed method.

Journal ArticleDOI
TL;DR: In this paper, a review of polymer microstructures fabrication methods for micro-tas, Lab-on-a-chip and BioMEMS developed so far are reviewed, where conventional plastic molds of hot embossing, injection molding and casting have been applied for fabrications of the micro structures with improvements of precise temperature control etc.
Abstract: Fabrication methods of polymer microstructures for μTAS, Lab-on-a-chip and BioMEMS developed so far are reviewed. Conventional plastic molds of hot embossing, injection molding and casting have been applied for fabrications of the microstructures with improvements of precise temperature control etc. New silicone like material, PDMS have been widely used in μTAS. Some UV photolithography methods have also been developed to realize 3D microstructures. Surface micromachining technologies using polymer as the structure and positive photoresist as the sacrificial layer are another potential fabrication methods in μTAS.


Journal ArticleDOI
TL;DR: In this article, an asymmetricaly driven Parallel plate (ASP) tilt mirror (TM) was designed for the purpose of high productivity and high mechanical reliability, the structure of ASP-type TM is very simple and it can be made by using bulk micromachining of SOI wafer.
Abstract: We have developed micro mechanical variable optical attenuators (VOA) using an electrostatic micro torsion mirror combined with fiber-optic collimators. For the sake of high productivity and high mechanical reliability, we have designed ASymmetricaly driven Parallel plate (ASP) Tilt Mirror (TM). The structure of ASP-type TM is very simple and it can be made by using bulk micromachining of SOI wafer. As a result, we have successfully downsized the VOA package to 5.6 mm in diameter and 23 mm in length. Optical performance is excellent for the optical communication network, small insertion loss of 0.8 dB and polarization dependent loss of 0.2 dB have been obtained.



Journal ArticleDOI
TL;DR: In this paper, a novel electrochemical sensor using a gold thin-film electrode formed on a carbon-fluorocarbon membrane was developed for the detection of toxic gas such as arsine.
Abstract: A novel electrochemical sensor using a gold thin-film electrode formed on a carbon-fluorocarbon membrane was developed for the detection of toxic gas such as arsine. The sensor shows a good linearity and long term stability. The output current of the sensor using a carbon-fluorocarbon membrane was not affected by ozone gas. These results indicate that the sensor is more useful in practical field.