Inverted glasses are used to see flip vertical view or flip horizontal view. Namely, our field image can be rotated by 180 degrees with this device. Inverted glasses are composed of triangular prisms, which enable to locate the field image by total reflection. In recent years, it used to investigate the sensory adaptation. Researches concerned psychology and brain science using it has been actively. Most of researches in these fields were made for working and adaptability of the brain. However, the researches about the movement of the line of sight have not been investigated so far. In this laboratory, we have developed a system for detecting line of sight. Therefore, in this research, for the first time, we developed inverted glasses that are equipped with transparent optical sensors, as shown in Fig. 2. Using this device, we measure the movement of the line of sight when the field image is rotated by 180 degrees.

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We propose and test a technique for selective self-assembly of a several kinds of PDMS blocks with the identical size and shape, using the patterned application of adhesive material. Hydrophilic treatment in specific patterns is applied to the surface of millimeter PDMS blocks using excimer light, which makes the adhesive to attach only on the hydrophobic part. As a result, the PDMS blocks bound selectively to those with identical patterns in the stirring container. We defined the bonds between the same pattern as “correct” bonds and unintended bonds as “erroneous” bonds. We confirmed that the contrast of bonding force between the “correct” and “erroneous” bonds is responsible for the bonding selectivity.

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This paper reports a uniform array of microneedles and enabled electrotactile feeling. In our prior work, we successfully lowered the voltage that required to present tactile sensation by making needle-shape electrodes, penetrating through stratum corneum which has high impedance. However, the non-uniformity resulted in localized pain and/or distributed stimulation. To solve the problem, we proposed the new fabrication process to make micro-needle electrodes. We successfully achieved to uniformize the needles, solved localized pain and/or distributed stimulation in two dimentional tactile sensation. Also, using large area micro-needle electrode array, we successfully present three different patterns of signal to the subjects, made them identify the signals. This microfabrication-enabling technique will offer a new medium for information communication technologies.

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The dragonfly changes how to move four wings by way of flying. When accelerating, all the wings flapped at the same timing When gliding, don’t flutter and only changing the wing angle slightly to change the direction. When hovering, move the front and rear wings alternately. Cancel the reaction when the front wing was dropped with the rear wing. In the same way, cancal the reaction when the rear wing was dropped with the front wing. My research is to develop a robot that imitates dragonfly. And to make a mechanism to move the front wing and the rear wing alternately to hover.

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In this study, we created a surface that imitated lotus leaves, and clarified whether improvement of water repellency is obtained by the hierarchical structure of lotus leaf surface .To imitate, a surface was prepared by subjecting the Si surface to patterning by dry etching using DeepRIE and aligning the cylinder on a hexagonal lattice.A surface having a diameter and a pitch changed by 10 μm to 150 μm at the minimum of 40 μm was prepared for the produced cylinder .This surface was immersed in PS solution to decorate the surface with PS.Results The average contact angle was 138.3 °, which is an improvement in the contact angle of about 8 ° compared to the surface on which only PS was formed.

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On-chip concentration of samples using nanometer-sized structures fabricated in a microchannel is an effective method to improve detection sensitivity in μTAS. We proposed on-chip concentration of DNA samples using a nano-slit, which is a channel with a depth smaller than a diameter of DNA molecule. The concentration is based on an entropy trap at the boundary between the microchannel and the nano-slit. Therefore, concentration is achieved only by adjusting applied voltages. In this study, we verified the feasibility and the performances of the proposed concentration experimentally. When we applied 0.3 V for 100 s by using 30-nm deep nano-slit, we succeeded in concentration of λ DNA at 25 times the concentration rate.

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In this study, we report development and improvement of desk top type reactive ion etching systems for micro fabrication of various titanium alloy as materials for tough MEMS. The improvement of exhaust properties and the self-heated stage of the desk top type RIE was carried out for improving the processing properties. The self-heated stage is a specially designed cathode used for a thermal reactive ion etching developed in this laboratory. The self-heated stage was designed based on simulation for improving the etching rate by the temperature rise of the stage. As the result, we succeeded in improving the processing properties of various titanium alloy.

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In order to realize the smart agriculture system with internet of things, we are developing a system for automatic monitoring and controlling of growing environment of crops. The system primarily consists of sensors of nutrient (nitrogen, phosphorus, and potassium) and environment (temperature, humidity, wind speed, etc.) and automatic fertilizing machine. To perform quantitative analysis of nutrient on a cultivated field, the nutrient sensors essentially require the continuously usable reagent. As a preliminary study, we performed parylene-N coating against disposable chloride analysis reagents. It was confirmed that the disposable reagents acquired the reusability.

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We are developing a self-propelled fertilizer machine, which carries concentrated liquid fertilizer, moves on water, and ejects the liquid fertilizer to a paddy rice if necessary. By using a prototype self-propelled fertilizer machine, the rate of forced diffusion of pseudo-fertilizer liquid was estimated. We have confirmed that the fertilizer has been spread 20 cm within 2 seconds. The method of forced diffusion can potentially be fast enough to manure to a paddy rice.

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Static gravimetric method with flying start-and-finish is widely used for calibration of large and medium liquid flow for its advantage of maintaining continuous flow through the flowmeter. However one needs to take careful measures in implementing this method in low flow systems to obtain good accuracy. At NMIJ/AIST, we adopted this calibration method using a pair of high speed switching valves as diverter for flow range below 1 L/h. This paper discusses the timing error of the diverting valves evaluated according to ISO4185 and also describes some of the main features of the gravimetric system using this high-speed switching valves.

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Optical trapping is used for many studies. However, optical trapping traps only very small droplets. Therefore, observation of the trapped droplet is difficult. We tried to observe the droplet with several observation systems. First, an objective lens with a variable iris is used. The iris cuts scattering light of trapping laser. Second, a telecentric lens is used instead of the objective lens. The telecentric lens catches only parallel ray. Shape of droplets can be observed without scattering light. Third, a color filter and backlight are used to cut almost all laser light and observe droplets as shade. In this, droplets are too unclear to observe. To count droplets, first and second ways are used. However, to observe in detail, this observation system needs to be improved.

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Multi-scale product design system is designed to design the product or material across the micro-scale to macroscale continuously. The simulation of phase transition in the multi-scale spaces is tried to carry out using the multiscale product design system.

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This paper reports evaluation of mechanical properties and fracture strengths of polycrystalline silicon germanium (poly SiGe) film with Ge concentrations of 46.4－87.0 at% using tensile testing and indentation test. Thicknesses of the SiGe film were 4.8－10.0 μm, depending on Ge concentrations. As a result, Young’s moduli of 110－127 GPa and 129－149 GPa were obtained from tensile testing and indentation test, respectively. The obtained Young’s moduli had a low correlation with Ge concentrations and were similar to Young’s modulus of poly Ge film. In the tensile testing, fracture strengths of the SiGe films were 1.1－1.7 GPa. Due to brittleness of the SiGe films, the obtained fracture strengths were thought to be affected by surface damage caused during device patterning.

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This paper describes a development of triple-coaxial flow device to fabricate micro-tube for microbial culture. Microbes are used in many fields, such as food, medicine, environmental and energy. We proposed a microbial culture system using hydrogel micro-tubes, which can protect the target microbes inside from competitive microbes outside of the tubes while allow oxygen and nutrition to diffuse through. The hydrogel microtubes can be produced by a microfluidic device, which can precisely control the flow and therefore, the tube geometry. For practical applications of the microtube-based microbial culture, it is important to produce a hydrogel micro-tube continuously. We proposed and developed a fluidic system that can produce micro-tube serially. We characterized the triple-coaxial flow device and verified the availability of the system.

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In this study, we report on a MRI-compatible force sensor with enclosed liquid using pressure transmission. The MRI-compatible force sensor consists of contact portion and sensing portions, and connecting pipes. The force applied to the contact portion is changed to inner liquid pressure. Since the pressure is transmitted to the sensing portion through liquid, the force is measured by the sensing portion in the outer side of MRI. The MRI-compatible force sensor is capable of detecting normal force and shear force with the sensitivity of 11.2 mV/N and 21.3 mV/N. We took MRI images of the measurement object with and without the MRI-compatible force sensor. The signal-to-noise ratios (SNR) were 83.2 and 89.0, respectively. Thus we confirmed that the proposed force sensor could be used in MRI.

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We developed a stretchable thermoelectric generator using folding deformation, like an origami. The stretchable thermoelectric generator consisted of flat and folded section. Rigid thermoelectric elements were arranged on flat sections and folded sections produced stretchability. First, an electronic substrate made from polyimide copper film was folded, and conventional rigid Bi₂Te₃ thermoelectric elements were arranged on the folded substrate. The stretchable thermoelectric generator was denoted stretching deformation by 20%. Then, we evaluated output voltage of the generator using heater. In both folded and deployed states, as the input temperature increased, the output voltage of the device also tended to rise. The output voltage of the folded state showed smaller voltage than that of the deployed state device. The reduction can be improved by making folding deformation uniformly.

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The present study investigated the influence of the surface wettability on the behavior of thin liquid film formed around elongated boiling bubble and heat transfer characteristics in flow boiling in a minichannel. Initially the dynamic behavior of the thin liquid film was observed through the air bubble injection experiment. Dewetting of thin liquid film was observed on the silicon surface. On the other hand, the dewetting of the thin liquid film was found to be prevented by use of a superhydrophilic surface. The minichannel boiling experiment was conducted to investigate the effect of the dewetting prevention on boiling heat transfer. For the superhydrophilic surface, the critical heat flux was 3.5 MW/m² that is 3.2 times higher than the bare silicon surface. Super-hydrophilization of the surface was found to be effective to prevent dewetting of the thin liquid film and enhance the critical heat flux in flow boiling in the minichannel.

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We fabricated a stacked type thermoelectric module ( 4mm × 4mm ) on a 4pm SiN_x free-standing film using a vacuum deposition process through a shadow mask. We proposed the structure of the device to the multi-layered structure to decrease the electrical resistance of the device. Cu and Ni were used as thermoelectric materials. A silver paste was painted on the center of the module for electrical conduction path, and a polyimide film was coated as an insulator by a spin coating. The output power of the micro-generator was 4.5 nW when the heating temperature was 245°C.

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BiFeO₃ thin film on DyScO₃ substrate was fabricated by RF sputtering and annealing. The BFO thin film is expected to be used for ferroelectric memories, piezoelectric devices, sensors and solar cells. DyScO₃ substrate is the smalllattice-mismatched substrates for BFO thin film. It was found that the (110) peak area which shows the crystallinity of BFO was appeared from X-ray diffraction (XRD). From results of X-ray photoelectron spectroscopy (XPS), BFO thin film has Fe²⁺ and Fe³⁺ statement. The materials of BiFeO₃ thin film on DyScO₃ substrate have the effectiveness in the future.

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We created the non-spherical liposomes with artificial micro-cytoskeleton. First, we fabricated micro-cubic frames with 3D-laser-printed photoresists. Next, we formed water-oil-water interface on the faces of these microstructures in a microfluidic channel. Finally, we confirmed whether this interface was lipid bilayer membrane by using α-hemolysin as a membrane protein. As a result, we successfully observed the solution encapsulated by lipid bilayer membrane formed around the microstructures.

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This paper describes a fabrication method of patterning stimuli-responsive hydrogel microfibers. Stimuli-responsive hydrogel microfibers are consist of sodium alginate and poly(N- isopropylacrylamide-co-acrylic acid) Micro fibers are fabricated with a micro fluidic nozzle. We examined the relationship between a diameter of fibers and a flow rate of sodium alginate and poly(N- isopropylacrylamide-co-acrylic acid). We confirmed the flow rate was proportional to the microfiber diameter. We also investigated the shrinking ratio of a microfiber to stimulus and confirmed a temperature responsive of the microfiber. We finally injected a fiber into carboxymethyl cellulose and printed a straight line by controlling automatic stages. Our proposed method could be applied to 3D printing of functional materials.

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A novel diaphragm design was proposed for enabling wide-range pressure sensing platform using a universal strain sensor chip. A pressure sensor consists of a metal diaphragm designed to meet sensor specifications, and the sensor chip attached on the diaphragm. The sensor chip has four piezoresistive gauges concentrated on the center, and it outputs voltage depending on strain difference between x and y axes. This concentrated gauge design gives the diaphragm diversity in its design. Two diaphragm designs, rectangle type and hour-glass type, were proposed to enable this concept by giving large XY strain difference at the center of the diaphragm. It was verified that a sufficient sensitivity could be obtained with the rectangle type even with thicker diaphragm than the conventional circle one, and the sensitivity was almost doubled with the hour-glass type. High robustness against assembling position error of the sensor chip was also verified.

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We developed a portable odorant detection system consisting of CMOS imaging sensor and collagen micropillars with cells that express olfactory receptors. Although the sensitivity of the CMOS image sensor was insufficient to detect the fluorescence signal from a single cell, stacking cells in the pillars allowed vertical accumulation of fluorescence from each cell and achieved supply of sufficient odorant-induced fluorescence to the CMOS image sensor. We think that our portable odor detection system will be a useful platform for quantitative and selective portable odorant sensor.

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This paper describes an evaluation of the effect of three-dimensional (3D) tissue shape on differentiation ratio and spatial distribution of neurons. We controlled the 3D tissue shape by culturing neural stem cells in a closed agarose microchamber and induced differentiation of neural tissues with various 3D shapes. By measuring the neuron ratio in the neural tissues, we confirmed that thinner tissues have higher neuron ratio and more uniform distribution of neurons. We believe that our culture method could fabricate neural tissues of high neuron ratio and uniform distribution of neurons and be application to drug screening of 3D neural tissues.

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Currently, the number of patients with severe chronic kidney disease in Japan exceeds 320,000. Most of this patients goes to the hospital three times a week and must receive about 4 hours of dialysis treatment every time. Therefore, we aim to develop an implantable dialysis system that uses a MEMS technology to make the dialysis system smaller and simpler. In this process, long-term in vivo experiments with small animals are advantageous, but at that time, blood coagulation management becomes a problem. Therefore, in this paper, the appropriate dose of heparin was quantitatively evaluated from the viewpoint of APTT by in vivo experiments using rat. It was confirmed that the halflife of heparin in the rat body was about 15 minutes. It is also expected that longer-term evaluation of devices becomes possible by adjusting heparin dose.

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In this study, we report on a blood pressure pulse wave measuring device with a function to reduce the influence of height difference of body motion. Our device consists of triaxial force sensor array for measuring blood pressure pulse wave and absolute pressure sensors for measuring height of device based on heart. The height difference is converted from atmospheric pressure difference by absolute pressure sensor. Blood pressure pulse wave was calibrated by adding pressure difference converted from the height difference. We measured blood pressure pulse wave and height difference before and after lowering the wrist by 400 mm. The error of height difference was 22.2±97.8 mm. The difference of systolic blood pressure was decreased 80 % after calibration. Since difference of systolic blood pressure was decreased, we could reduce the influence of height difference of body motion.

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In this study, we report on a blood pressure pulse wave measuring device with the function to reduce the influence of body motion. The device consists of two triaxial force sensors for measuring pulse wave and noise of body motion. The noise generated from body motion is reduced by subtracting the measured value of the body motion sensor from that of the pulse wave sensor. We measured the pulse wave and the noise during the body motions in the back and forth and the right and left of the wrist, and calibrated by subtracting the value of noise from the pulse wave. The standard deviation of the amplitude of calibrated wave decreased 72.0 % in the body motion of back and forth, and 4.13 % in the body motion of right and left. Therefore we could reduce the influence of body motion of the wrist.

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We developed a microfluidic device which allows repeated electrofusion of liposomes. In the present device, several liposome populations which contain different biochemical components are stored in respective reservoirs next to the fusion chamber equipped with electrodes. The target liposomes are individually manipulated by an optical tweezers and brought into contact in the fusion chamber, where the electric pulses are applied to induce membrane fusion and contents mixing. The microchannel geometry was devised such that liposomes are properly stored in reservoirs with easy manual pipetting. The effect of electric pulses was localized within the fusion chamber, while liposomes in reservoirs were unaffected. The present system allows serial basic operation in situ, such as reagent mixing (substrate supply), aliquoting, and sampling in sub-picoliter volumes using liposomes as a biomimetic dynamic reactor.

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The influence of deposition bias voltage on the tensile properties of single-crystal silicon microstructure fully coated with 150 nm-thick diamond like carbon film using plasma enhanced chemical vapor deposition were investigated. The fabricated structure had dimensions of 120 μm long, 4 μm wide and 5 μm thick. PECVD DLC film has the average sp² phase of 44%, sp³ phase of 20% and hydrogen content of 36% from photoelectron spectroscopy (XPS), and thermal desorption spectrometry (TDS) analysis. With increasing negative bias voltage, sp³ phase increased and sp² phase, hydrogen content decreased. The tensile strength of DLC coated SCS samples was 13.2%-29.6% higher compared to the bare silicon samples. The -400 V bias showed the highest strength of 3.94 GPa, which was in a good agreement with the measurement result of DLC fracture toughness. The deviation in strength reduced significantly with increasing negative bias voltage.

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Deep Reactive Ion Etching1),2),3) is well established as a commercial technique for forming Micro-Electro-Mechanical Systems (MEMS) devices. Over the last decades, development work has led to increases in silicon etch rate of an order of magnitude while requirements for etch depth uniformity and profile control have become more stringent as the wafer size has increased from 4 inch up to 200/300 mm. This paper describes the leading edge technology and recent improvement of Deep Si RIE on Precise and High rate processing.

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This paper introduces an implantable blood separating device using a curved and branched channel. The separation is aiming at lowering the coagulability of blood by reducing platelets, one of the typical coagulation factors. For applying blood separation inside the body, the device is required to perform in the condition of more than 800 mL/min of blood flow rate and 80 mmHg of pressure. These factors are not suitable for microsystem because of its enormous pressure loss which blocks the blood flow. Therefore, we fabricated the channel of 2.5 mm square section with acrylic board and conducted in vitro experiments with conserved cow blood to indicate the separation capacity of the device. We deduced the relation between hematocrit and blood coagulations by experiments, which verified that the proposed device was effective.

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This study presents a stimuli-responsive gel-based gripper that can be wirelessly manipulated using infrared (IR) light. We fabricated IR-responsive gel (pNIPAM-SWCNT gel) by uniformly dispersed single walled carbon nanotubes (SWCNT) that efficiently absorb IR light and generates heat. We confirmed that pNIPAM-SWCNT gel has IRresponsiveness by IR irradiation experiment. By using a photomask, we successfully patterned the gel in the shape of a gripper. We believe that our gel gripper could be applied to a remote controlled manipulator in vivo, and contribute to the development of non-invasive treatment.

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In this report, a MEMS torsional mirror with torsion beams made of silicon nanowire has been proposed and was fabricated. The silicon nanowires on the device structure were batch-fabricated as the torsional beams. Torsional stress of the beams was decreased by downsizing the diameter of the beams considering the scale effect. We also have proposed the fabrication process of the mirror device which integrates the silicon nanowire of 1-μm square in the 5-μm-thick device layer of silicon-on-insulator wafer. The mirror of 100 μm square was designed and fabricated. The dimensions of the fabricated wires was same as that of designed, which shows that we successfully controlled the wire dimensions.

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A vertical electret energy harvester has a problem of pull-in between electrodes. We proposed the harvester with spacer. Using the spacer, the surface potential of electret can be high because the spacer prevents the pull-in of electrodes. Therefore, the output power increased by the spacer. However, the change in electrostatic capacitance is decreased because the gap increases by the spacer. There is a trade-off relation between thickness of spacer and power. We evaluated the relation between surface potential of electret, thickness of spacer, and output power. Using a spacer with a thickness greater than 36 μm, the electrode can vibrate when the surface potential was −630 V. Moreover, the output power was maximum when the thickness of spacer was 36 μm.

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Currently, Research and development of tactile displays as data presentation devices using the tactile sense are making great progress. However, the challenge is that the presented sensation cannot be quantitatively evaluated because there is no index of tactile sensation. We propose a new evaluation method by measuring and quantifying the tactile sensation using tactile samples with variation of a single parameter, such as surface roughness and hardness. In this work, we demonstrate micro-patterned tactile samples made of SU-8. They have a concavo-convex shape of stripes. Differences in roughness were expressed by changing the pitch and width of the stripes and height of the concavo-convex. We also made tactile samples made of PDMS. The polymerization ratio of base resin and hardener ware changed to produce tactile samples with identical surface roughness but different hardness.

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We developed a portable device for biological nanopore recordings with a liquid-capturing system. Recently, biological naopore sensors increasingly attract attentions, but their stability is still an important issue for their mobile applications. Hence, we combined the cup-like reservoir with a glass capillary–based lipid bilayer device. The reservoir, a cylindrical well with three claws, covers the capillary tip and allows to catch the solution by the surface tension. We formed a lipid bilayer on the tip of the capillary by a conventional painting method and reconstituted nanopore into the lipid bilayer. We succeeded in monitoring an ionic current by α-hemolysin incorporation and DNA translocations through the nanopore.

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In recent years, 3D printers have been utilized in many fields. The size of 3D printed object is ranging from several micrometers to several meters. In particular, microstereolithography makes it possible to produce 3D micro objects whose size is less than a few centimeters. In this process, photopolymer is selectively polymerized by scanning a laser beam. To produce precise 3D micro objects, exposure conditions such as laser power and scanning speed should be optimized to reduce over exposure or under exposure. Inadequate optimization of the exposure condition causes to shape errors. To evaluate the shape errors, we have developed a 3D shape measurement system suitable for evaluating transparent 3D micro objects produced by microstereolithography. In experiments, we demonstrated that micropillars whose diameters are on the order of several hundred micrometers could be observed by our 3D shape measurement system.

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In this study, we have developed a metalized spinning-top microturbine driven by an ultralow-power laser beam. This microturbine was supported by the upper and bottom bearings. The metalized microturbine was fabricated by the combination of two-photon microfabrication and electroless copper plating. In experiments, we succeeded in driving the microturbine by focusing the laser beam on the blades of a microturbine. In order to drive the microturbine at a higher velocity, we used the flow around a laser-induced microbubble. As a result, the microturbine could be rotated at a speed of 3500 rpm. Finally, we demonstrated the driving of spinning-top microturbine attached on an optical fiber tip. Such optically driven metalized micromachines will be useful for functional lab-on-a-chip devices and microtools for biological research.

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This paper reports on a gradient micro coils for MRI. The gradient micro coils was fabricated by assembling flexible Cu/polyimide substrate to 3D printed jig with complicated 3D structure. Since the micro coils have spatially high positional accuracy, our gradient micro coils has high gradient magnetic field efficiency with high linearity. The number of turns and gap of the coils were 4 turns, 10 mm. We took MRI images of the cooking oil and measured the efficiency of the gradient coils. The efficiency of X, Y and Z-axis gradient coils were 50.1, 51.5, and 50.1 mT/m/A. Since the gradient magnetic field efficiency was about 13 times stronger than the hand-winding coils, high resolution MRI image can be expected.

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