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Semiconductor silicon has realized various kinds of valuable electron devices. CMOS technology is the present standard silicon process to fabricate integrated circuits and systems. Therefore, the word “Post-CMOS” has been an important word which means that the technology makes it possible to fabricate various kinds of MEMS sensors/actuators/passives with highly sophisticated modern CMOS devices. Also, it emphasizes that MEMS devices fabricated by post-CMOS technology has “high compatibility” with “silicon FABs” that are most universal and distributed fabrication facilities in the world. High performance devices and fine microstructures can be fabricated by universal post-CMOS fabrication processes at present. Post-CMOS compatible process is a key technology to realize ultra-high-performance silicon MEMS tactile sensors in this study. We, humans have very sophisticated sense of touch on our fingertip skin, and we can recognize and distinguish various and delicate difference of touch feelings obtained by “sweep motion” of fingertip on various kinds of materials and objects. Our fingertip skin has the highest density of force and vibration (mechanical) receptors like Meissner’s corpuscles and Merkel disks under the surface skin layer where fine pitch patterns of fingerprint are formed on. It is known that human’s fingertip has a very high spatial resolution below 100µm or less, and can recognize existence of 13nm-pitch patterns as reported recently. The high performance of our fingertip sense of touch has never been realized by any tactile sensor device. In order to reproduce artificial sense of touch like the fingertip, very high performances on “spatial resolution” and “input sensitivities” are required to integrate all on a small tactile sensor. Therefore, CMOS-compatible fabrication technology is the most suitable process to fabricate such high-performance tactile sensors with integrated functions. Based on a silicon post-CMOS compatible process, we have realized high performance silicon MEMS tactile sensor called “Nano-tactile sensor”, which is comparable to the performance of fingertip sense of touch. In this tactile sensor device, all the mechanical structures are made from single crystalline silicon which is the active layer of SOI wafers. No elastomer/polymer structures are used in the mechanical sensing structure, and softness and elasticity necessary to tactile sensing are realized by silicon micro mechanical structures. All the fine mechanical movements and sensing circuits with strain-sensitive diffusion resistors (i.e. piezoresistors) are designed by 2D-CAD, and the characteristics can be controlled by layout pattern sizes. The contactor parts of the tactile sensor have curved shape which is similarly designed to the cross-section of a fingerprint, and its suspension springs are designed to have similar spring constant with human’s fingertip skin surface. In the latest version of our “Nano-tactile sensors”, six contactors with fingerprint-like shape are integrated at a pitch of 500µm to get distributed tactile images at a high spatial resolution. The pitch of 500µm corresponds to the average value of human’s fingerprint patterns. Each fingerprint-like contactor reproduces vertical motion (by micro roughness) and horizontal motion (by frictional force) of a fingerprint closely under sweeping motion of fingertip in touch feeling measurement. Spatial resolution of our tactile sensor reaches to sub-micron (200nm) in the finest version, and its force resolution of input reaches below 50µN range. These high performances are enough high to reproduce part of our fingertip sense of touch. The Nano-tactile sensors can get touch feeling waveforms of “hair surface condition”, “skin texture and the condition”, and touch feelings of various kinds of “papers” and “clothes” at a high spatial resolution like our fingertip skin. In the lecture, experimental results of very high-resolution tactile sensing are presented, and their importance and novelty are discussed. Machine learning based on deep neural network (DNN) has become very important for sensing data analysis. We think DNN is very important to understand/reproduce human sense of touch since a trained DNN behaves similarly with human’s senses based on our experiences. Since a lot of sample data are required for such applications, we have developed a measurement system called “Touch-Feeling Scanner”. A number of tactile sensing data can be measured by the touch-feeling scanner integrating a Nano-tactile sensor device. Obtained signals with the scanner were applied to train a DNN for discrimination of different kinds of clothes. 10 kinds of cloth samples have been successfully discriminated at a correct percentage over 95% as an example. Combination of high-resolution Nano-tactile sensors and state-of-the-art machine learning (DNN) is a strong approach to reproduce human fingertip sensation for various valuable applications. Figure 1

In the present report, we have developed a tactile sensor with fingerprint-like array of contactors for obtaining the surface distribution of tactile information in high spatial resolutions. Six high resolution sensing modules of contactors with biaxial detectors were integrated in line at a pitch of 500 μm, the typical pitch of fingerprint ridges. Each sensing module independently detected the micro surface shape and locally generated frictional force on the object surfaces. Mechanical analysis of the fabricated sensors showed good sensitivities and highly linear responses. Consequently, the measured detection resolutions of surface shape and frictional force were 0.17 μm and 9.9 μN, respectively. The experimental performance evaluation of fabricated sensor was measured in the distribution of tactile information by sweeping the sensor with a yaw angle. Additionally, the 3D surface shape of weave structure and surface distribution of frictional force in a woven fabric with 0.4 mm pitch of threads in high spatial resolution was clearly visualized/observed. Moreover, the directionality of tactile information of the fabric surface distribution was successfully realized using the tactile sensor with the array of contactors by sweeping in different directions.

This paper reports the results of development of a tactile sensor system (Multi-tactile Scanner) that can easily measure and evaluate the surface texture of a small area in real time. A high resolution fingerprint-like MEMS tactile sensor that can measure the sensations of surface shape, friction and hardness have been developed and reported [5]. In order to expand the application field of this tactile sensor, we need to support it with a stable mechanical system. The Multi-tactile Scanner integrates a roller-type traveling mechanism for precise scanning of the surface and a mechanism for adjusting the contact pressure of the sensor so it is appropriate for the target object. An integrated rotary encoder provides a spatial resolution of 2 μm. Experimentally, the Multi-tactile Scanner was used to measure and evaluate a body surface in real time.

This is the first report of an antenna-shaped MEMS tactile sensor that integrates a detector for correcting the device's measuring posture in a single chip. Many objects are difficult to measure using conventional tactile sensors. For example, it has been difficult to measure objects with curved surfaces or holes because of the size and measurement method of the sensors. Our solution to these problems was inspired by the antenna characteristics of insects and enables us to measure complex and intricate areas in a small and narrow space. The antenna-shaped angle detection integrated in the tip of the device detects the relative state of the target and simultaneously acquires fine irregularities in micro areas for the first time.

This paper reports a very high-performance tactile sensor system (Touch Feeling Scanner) that can easily and precisely measure the fine surface textures of various kinds of samples. Since human's fingertip can discriminate surface texture below $100 \mu \mathrm{m}$ range easily, it is considered that spatial resolution higher than $100 \mu \mathrm{m}$ is required for the sensors to reproduce the sense of touch on our fingertips. Since such precise measurement usually requires precisely driven stage, there are limitations on the sample shape, the size, and the measurement location of the samples. In order to realize both high special resolution and high adaptability to many applications, MEMS high resolution tactile sensor that we had developed is integrated in the “Touch Feeling Scanner” with novel measurement mechanics in this study. Attitude stabilization mechanism, crawler-type distance detector, and signal processing units for acquiring output signals from the tactile sensor are combined for precise measurement on samples. The completed system of touch feeling scanner showed significant performance reproducing the original performances of high-resolution tactile sensor evaluated with a motorized precise stage.

In this paper, we report the effect of parylene-C coating on a high resolution 2-axis MEMS tactile sensor for protection of the contact surface of measured samples. Thin parylene-C layer was coated on overall device chip surface, and the improvement effect was evaluated to use it as a coating material suitable for protection of the measurement surface. The effect of parylene-C layer coating to mechanical characteristic of the tactile sensor was within 5%, even though 3μm-thick parylene-C is deposited on the suspension springs. Protection effect of the parylene-C layer was also evaluated with measured samples of color paint on a metal. As a result, the depth of scratches made by sensor sweeping motion was much reduced by 60%, and the sensitivity and the spatial resolution was almost not affected. Parylene-C is an effective material for coating of high resolution tactile sensor surface.

In this study, we focused on direct and quantitative monitoring of sap dynamics in plant stems, and proposed the microscale xylem sap flow sensor. This sensor facilitates the simultaneous measurement of flow velocity and direction by combining the principles of a Granier sensor and a thermal flow sensor. We fabricated micro-sensor chips for functional verification by using MEMS technology, and assembled them on a resin film to facilitate mounting on the epidermis of plants. Furthermore, we measured the sap dynamics by using an experimental setup, and succeeded in measuring the flow velocity and direction at the same time.

An olfactory display is necessary for effective multimodal information communication. The relatively large size of current olfactory displays does not support integration with other information devices. Thus, in this study, a heat-driven-type microelectromechanical system (MEMS) olfactory display that is only a few square centimeters in size and, thus, suitable for integration, is proposed. The olfactory display was fabricated by implementing a microfabrication process, and the fundamental driving conditions for the heater and valve were confirmed. Furthermore, a perfume diffusion experiment was conducted to characterize the olfactory display. The diffusion of the perfume was successfully synchronized with the open/close time of the valve.

In this paper, a motion-tracking method that obtains the position (motion) information of each part of a running MEMS (Micro Electro Mechanical Systems) tactile sensor is proposed as the first step toward developing a material surface shape detection model. By observation and motion tracking with a high-speed camera, the motion information of each part of the sensor can be obtained, and the motion of the top of the contactor is acquired from the calculation. Results show that the top of the contactor follows the sample surface closely.

In this paper, novel semiconductor silicon based MEMS tactile sensors for measurement of fingertip sensation and their high resolution detection ability of surface texture are presented. All the device structure is made from silicon single crystal layer on SOI wafer. The contactor of tactile sensor is designed to have similar size and cross-section with a human's fingerprint. Two-axis movements of a contactor tip are independently detected to obtain the real vibrating motion of a finger print under active sensing (sweeping) motion of fingertip. On the other hand, macro-area tactile sensors of “overall contact pressure” and “macro-area sliding friction” are also integrated on the same chip, since combination of micro and macro tactile information is important in human's fingertip tactile sensation. The multiple detection abilities will be very powerful for understanding how humans recognize and distinguish objects using their fingertip skin sensation. As an example of original application, “visualization of cloth surface texture” is demonstrated.

In this study, a sensor device based on MEMS technology is proposed to quantitatively monitor the health conditions of plants using biological information (i.e., pH and electrical conductivity (EC)). The proposed sensor device comprises an ion-sensitive field-effect transistor (ISFET)-based sensor (for pH measurement), an EC sensor, and a p-n diode temperature sensor (for adjusting the temperature dependency of the pH and EC measurements). A prototype of the proposed sensor device was fabricated. Furthermore, the basic performance of the ISFET-based pH sensor and EC sensor was evaluated. Through experiments with mimicking plant, the feasibility of measuring the internal biological information (pH and EC) of plants was demonstrated.

This paper reports a durable MEMS slide valve with enhanced controllability by long-stroke actuation and high pressure resistance more than 1MPa. The features are realized by combination of precise processing accuracy of MEMS and powerful driving force of external actuator. The merits of MEMS microvalves (i.e. highly accurate micro structures) and the merits of "macro-scale" valves (i.e. long-stroke/powerful actuators) are combined to solve problem of conventional MEMS microvalves for high-power applications with high pressure fluidic flow. This microvalve copes with both high pressure resistance more than 1MPa and highly accurate flow rate control ability from 5 to 100ml/min for the first time.

In this study, a novel “micro-macro” planer MEMS tactile sensor integrating two different scales of tactile sensors has been developed for artificial realization of human's fingertip feeling. The “micro-scale” tactile sensor detects “micro surface shape” and “micro-area frictional force” that are generated and detected at a fingerprint on human's fingertip skin. On the other hand, the integrated “macro-scale” tactile sensor detects “overall contact pressure” and “macro-area sliding friction” that are detected by wide-area on fingertip skin. Since the combination of “micro and macro” tactile information has an important meaning in human's fingertip sensation, this tactile sensor realizes multi-scale tactile detection at the same time and at the same point on the sample surface. It will be a very powerful tool for understanding how humans recognize objects using their fingertip skin sensation.

Background Tumor size determination is subject to the measurement method used by endoscopists and is especially dependent on the air quantity. As the intraluminal pressure must be measured objectively to obtain an accurate tumor size measurement, insufflation can affect the results. Thus, we examined the utility of a micro-electro-mechanical-system (MEMS) pressure sensor hood. Methods Twenty consecutive air insufflation/deflation tests were performed in vivo using a dog’s stomach. Correlations between the actual pressure measured and the signal strength of the MEMS hood were measured. We marked 2 points 20 mm on the antrum and another 3 points, with insufflation corresponding to the maximum stable distance of two markings. We performed five insufflation/deflation tests to obtain the relationship between pressure and distances to accurately measure the distance under constant pressure. Results In the air insufflation/deflation test performed 20 consecutive times, the MEMS hood signal strength (V) and the pressure measurement sensor values (mmHg) showed good correlation. There was good correlation between intraluminal pressures of 2.5–40 mmHg and the two marking distances on the antrum (correlation coefficient 0.952) (P

In this study, a microscale phloem sap extraction sensor device based on MEMS technology is proposed to artificially extract phloem sap and monitor biological information in plant branches. The device consists of electrical resistance sensors to distinguish the positions of vascular bundles (xylem/phloem) and hollow-structured cantilevers with reservoirs for fluid extraction. A prototype of the proposed sensor device was fabricated. Furthermore, the performance of the position-distinction sensor was evaluated, and the feasibility of the fluid-extraction structure was validated.

This paper reports a very high sensitivity static electricity sensor assembled with a vertically mounted large area electrode. The electrode is fabricated by perforation of single crystalline silicon, and automatically aligned on an electrostatic actuator stage. The sensor measures a charged voltage of measuring object surface using a 4×4 mm2 electrode driven at the resonant frequency in vertical direction to the object surface. The charged voltage of surface is in proportion to the alternative current caused by change of capacitance existing between the electrode and surface. Realized resolution of static electricity was 1.96V, and it is about 100 times higher performance than the previously reported MEMS static electricity sensor.

In this paper, novel semiconductor silicon based MEMS tactile sensors for measurement of fingertip sensation and their high resolution detection ability of surface texture are presented. All the device structure is made from silicon single crystal layer on SOI wafer. Two-axis movements of needle-like contactor tip are independently detected by the two independent suspensions. The movement is precisely detected by integrated strain detection circuits. Obtained results from the sensors were carefully analyzed with statistical analysis and FFT, and various objective facts have been made clear. For example, the rougher the feel texture of a paper surface, the lower the mutual relation between the time-domain waveform of surface micro roughness and the corresponding instantaneous frictional force. This is an example of never known knowledge about surface feel of touch, and a lot of information to quantify the sense of touch has been extracted using the tactile sensor in this study.

We aim to develop a MEMS mirror fabricated by micro-fabrication technology to realize a phase-shift device, which is a key component of a two-dimensional Fourier spectrometer. This MEMS mirror is capable of high-precision movement in the vertical direction parallel to the reference plane. In this study, a vertical electrostatic comb-drive actuator and capacitance sensor were fabricated monolithically on a single chip, and then four of them were mounted around the movable mirror. We fabricated a MEMS mirror that was able to move in the vertical direction while sensing the tilting angle. As a result, it would be feasible to use this vertical comb-drive MEMS mirror with a sensing function for a phase-shift device that was able to control the vertical displacement and the tilting angle of a movable mirror.

In this paper, a versatile integration technology for thick-film silicon-on-insulator microelectromechanical systems (SOI-MEMS) devices with CMOS electronics using novel microbridge interconnections is reported. The microbridge interconnection proposed in this paper solves the problem regarding the electrical isolation and interconnection between CMOS and SOI-MEMS devices. The integration of SOI-MEMS requires only three additional photolithography steps for the CMOS wafers fabricated by a standard process. On the basis of the developed technology, SOI-MEMS devices integrated with CMOS circuits were fabricated using 20-μm-thick SOI wafers. No significant damage was observed in the measured characteristics of the fabricated CMOS after the integration of MEMS devices. In addition, the electrical isolation of SOI-MEMS from the CMOS substrate was successfully realized and confirmed in the experiment, keeping electrical connectivity between CMOS circuit terminals. The measured isolation resistance between MEMS and the CMOS substrate was more than 1012 Ω, and a proof voltage above 60 Vdc was observed. These values guarantee a small leakage current and a sufficient voltage swing for driving electrostatic microactuators. On the other hand, the resistance of the interconnection over a microbridge structure was below 1 Ω, which is sufficiently low for integrating low-noise microsensors. This integration technology can be used in realizing monolithically integrated SOI-MEMS sensor and actuator devices with high-aspect-ratio structures using the most cost-effective and versatile CMOS fabrication technologies.

We propose a microscale phloem-sap-dynamics sensor device to obtain the index of an internal plant condition regarding the transportation of primary photosynthates in phloem, which is an essential indicator of stable crop production under controlled-growth environments. In detail, we integrated a conventional Granier sensor with a thermal-flow sensor and devised an improved sensor device to quantify such index, including the information on velocity and direction of the phloem-sap flow using the microelectromechanical systems (MEMS) technology. The experimental results showed that although the proposed sensor device was approximately only 1/10 the size of the conventional Granier sensor, it could generate an output nearly equal to that of the conventional sensor. Furthermore, experiments using mimicked plants demonstrated that the proposed device could measure minute flow velocities in the range of 0–200 µm/s, which are generally known as the phloem-sap flow velocity, and simultaneously detect the flow direction.

In this study, a silicon multifunctional tactile imager with the simultaneous detection abilities of ‘3D surface shape’ and ‘temperature distribution’ of touching object has been realized with silicon LSI/MEMS technology. The pixel circuit array including a piezoresistor and a temperature sensor is integrated on elastic surface of pneumatically swollen silicon diaphragm. Also, elasticity detection of touching object has been simultaneously realized with signal processing in frequency domain. Prototype tactile imagers with a 3.1 mm × 3.1 mm sensor diaphragm integrating 420-μm pitch multifunctional sensor pixel array have been fabricated. In the evaluation experiments, the shape of a 1.5 mmϕ soft tube was successfully detected. Also, simultaneous measurement of surface shape and temperature distribution was performed using a heated metal pipe. The detectable lower-limit of vibration in this tactile imager was below 1.0 μm with signal bandwidth more than 2 kHz. Using the ability of vibration detection, the three kinds of materials with different elasticity (0.59–7.04 mN/μm) were successfully distinguished with the tactile imager. The highly sensitive and multifunctional tactile imager with versatile detection ability has been realized by sophisticated integration ability of silicon-MEMS technology.

This paper presents the integration of an inductor by complementary metal-oxide-semiconductor (CMOS) compatible processes for integrated smart microsensor systems that have been developed to monitor the motion and vital signs of humans in various environments. Integration of radio frequency transmitter (RF) technology with complementary metal-oxide-semiconductor/micro electro mechanical systems (CMOS/MEMS) microsensors is required to realize the wireless smart microsensors system. The essential RF components such as a voltage controlled RF-CMOS oscillator (VCO), spiral inductors for an LC resonator and an integrated antenna have been fabricated and evaluated experimentally. The fabricated RF transmitter and integrated antenna were packaged with subminiature series A (SMA) connectors, respectively. For the impedance (50 Ω) matching, a bonding wire type inductor was developed. In this paper, the design and fabrication of the bonding wire inductor for impedance matching is described. Integrated techniques for the RF transmitter by CMOS compatible processes have been successfully developed. After matching by inserting the bonding wire inductor between the on-chip integrated antenna and the VCO output, the measured emission power at distance of 5 m from RF transmitter was -37 dBm (0.2 μW).

In this study, stable detection principle of MEMS hardness sensor using "reference plane" structure is theoretically analyzed and demonstrated with experimental results. Hardness measurement independent to contact force instability is realized by optimum design of the reference plane. Fabricated devices were evaluated, and “shore A” hardness scale was obtained as reference in the range from A1 to A54 under a stable contact force. Contact force dependence was effectively reduced by 96.6% using our reference plane design (i.e. very stable to the contact force change). Below 1N contact force, maximal signal error of hardness is suppressed to A4. This result corresponds to the detection ability of fat's hardness, even if the contact force is instable. Thorough the experiments, stable detection of human body hardness has been demonstrated without any control of the contact force.

In this paper, a novel rotational MEMS diffraction grating for realization of micro-sized spectroscope system with SiOB (Silicon Optical Bench) technology is newly developed, and its evaluation results are reported for the first time. Since this device has “out-of-plane” optical surface on the rotational actuator, concept of micro optical bench is applicable to realize precision alignment in the micro spectrometer. A diffraction grating was fabricated by silicon, and it is mounted on the stage of an electrostatic rotational actuator. Driving the stage by ±3.5° at DC80V, wavelength of white light was successfully modulated in the range from 515nm to 763nm at an 11% diffraction efficiency.

In this paper, a new extraction method of information for quantification of the fingertip sense which is never extracted by previous tactile sensors is reported for the first time. The MEMS two-axis tactile sensor used for the purpose can get the correlation between the surface shape and the local frictional force at the same time and at the same point. Obtained correlative relationships using the device were carefully analyzed with statistical analysis and FFT, and various objective facts have been made clear. For example, the rougher the feel texture of a paper surface, the lower the mutual relation between the time-domain waveform of surface micro roughness and the corresponding instantaneous frictional force. This is an example of never known knowledge about surface feel of touch, and a lot of information to quantify the sense of touch has been extracted using the novel MEMS tactile sensor in this study.

In this paper, a novel configuration of (horizontal type) MEMS tactile sensor that can interact with micro surface roughness at a high resolution are proposed and reported for quantification of the fingertip sense. Two-axis movements of the contactor-tip are independently detected by the two independent suspensions. The contactor is sticking out of the side surface of the silicon chip, and its over-range motion is protected by the embedded stopper structure during the sweeping motion for tactile sensing on the object. In the evaluation experiment, Correlation between the surface shape and the local frictional force were successfully obtained at the same time and at the same point for many samples (paper, plastic, rubber etc.) for the first time.

In this paper, a thermo-pneumatic in-channel microvalve applicable to integrated blood test system is presented. Thermo-pneumatic actuator separated in drive chamber part and thermal expansion chamber part (two-chamber configuration) is newly proposed for the purpose to reduce direct heat transfer from microheater to flow channel. Polydimethylsiloxane (PDMS) is employed as the diaphragm material for a long stroke actuation in microvalve operation and high sealing performance of liquid. It is also used as adhesive layer between glass and silicon in the structure. The microvalve with the proposed structure was fabricated. Both static and dynamic flow control characteristics were evaluated with a liquid sample (DI water) and a gas sample (N 2 ), respectively. A high ON/OFF ratio of liquid sample was obtained thanks to the soft PDMS diaphragm. Liquid sealing performance in the closed state was high enough for our application (

In this paper, a new concept and potential demonstration of functional microfluidic integrated circuits using MEMS technology are presented. The fluidic integrated circuits were constructed utilizing analogous relationship between MOSFET and pneumatic microvalve with a diaphragm structure. The signal transmitted through the circuit is the fluidic signal, that is, the pressure or the flow-rate of the fluid. The pneumatic microvalve in this study is expressed by small-signal equivalent model similar to that of a MOSFET. Small signal behavior of microfluidic integrated circuits can be expected using the model, if the parameters in the model are extracted properly from fabricated microvalves. As an example of a fluidic circuit, pressure inverting amplifiers including integrated two microvalves were fabricated and evaluated. As a result, they showed sharp pressure transfer curves similar to MOS inverter circuits. A maximum pressure gain of 32.0 dB was obtained, and it can be used for pressure amplification in analog applications. In addition, they can be used as pressure inverter logic circuits for digital applications. Although the theory and design environment of the new microvalve circuit technology have not been established yet, multifunctional fluidic analog and digital circuits can be realized for special application fields different from electronic integrated circuits.

In this study, a sensor for blood cell counter has been developed using MEMS technology. The number of blood cells in human blood could be counted with this micro silicon MEMS device. Aperture-impedance method was used to detect blood cells as voltage signals. As a result of the investigations, suitable materials for the electrode of the device have been found. At first, polystyrene latex particles (PSL: Duke Scientific Corp.) were used to confirm the operation of the blood cell counter instead of the actual blood. The difference of the sizes of PSL particles were successfully recognized from the height of pulses and also the concentration of PSL particles were counted by the number of pulses. Finally control blood was introduced into the device, and both red and white blood cells were detected.

In this study, we propose a dual-axis hybrid-MEMS mirror for large-area 2D raster scanner composed of fast and slow driving gimbals. For simple fabrication and high driving performance, an outer gimbal for slow and large scanning has polymer SU-8 hinges with low rigidity, and an inner gimbal for fast scanning has Si hinges with high rigidity. The outer gimbal deflected over ±14deg. at non-resonant frequency of 60Hz refresh rate, and the inner one ±1deg. at the resonant frequency 22.9kHz. The 2D raster scanning of the fabricated mirror was demonstrated.

In this study, a new assembly technique of separately fabricated MEMS optical devices on fragile MEMS actuator stages has been developed to realize novel functional optical-MEMS devices. This technique realizes the “assist-free” alignment and fixing of vertically mounted optical devices by combination of “micro spring slider” and “trapezoidal alignment slit”. Various kinds of optical devices can be precisely aligned and stably fixed even on movable actuator stages supported by soft spring suspensions. In the experiments, micro mirrors were attached on electrostatic linear actuators and rotational actuators using this assembly technique, and a small average value of relative-angle error around 4/100 ° was successfully obtained.

In this study, the stable detection principle of a MEMS hardness sensor with “reference plane” structure is theoretically analyzed and demonstrated with experimental results. Hardness measurement independent of contact force instability is realized by the optimum design of the reference plane. The fabricated devices were evaluated, and a “shore A” hardness scale (JIS K 6301 A) was obtained as the reference in the range from A1 to A54 under a stable contact force. The contact force dependence on hardness sensor signals was effectively reduced by 96.6% using our reference plane design. Below 5 N contact force, the maximal signal error of hardness is suppressed to A8. This result corresponds to the detection capability for fat hardness, even when the contact force is unstable. Through experiments, stable detection of human body hardness has been demonstrated without any control of contact force.

In this paper, a tactile sensor with detection abilities of hardness and friction of object surface is proposed and reported. The new detection principles of friction and hardness are realized with the reference plane structure on the device. The device was fabricated with LSI/MEMS integration technology. Completed the devices were evaluated, and the measured normal force sensitivity was 0.07mV/mN/V. On the other hand, the shear force sensitivity was 0.73mV/mN/V. This performance corresponds to the detection ability of frictional coefficient around 0.1. Also, shore A hardness was successfully measured in the range from 22 to 99 HS.

In this paper, design and fabrication results of ‘in-plane’ type MEMS mirror device driven by rotational electrostatic actuators with angle sensing ability are reported for the first time. This MEMS mirror realizes rotational motion of a vertical mirror mounted on the SOI actuator stage, which can deflect or switch the reflected light angle in parallel to the same chip surface. Since optical fibers and the vertical mirror can be aligned with guide structures or slits fabricated by the same photolithography step, precisely self-aligned micro optical bench system with light deflection function can be easily constructed. In addition, electrostatic rotary encoder is integrated with the rotational actuator for detection of the absolute rotational angle of the mirror stage. The rotational actuator device was fabricated successfully, and ±2.4° stage rotation was obtained at a 96V actuator drive voltage. Also, in-plane optical light deflection has been successfully demonstrated with the rotational mirror put on the actuator.

In this study, we have evaluated the mechanical characteristic and the attractive force of the SU-8 containing magnetic particles. Then, we have fabricated the mirror device based on the mechanical characteristic of the polymer and evaluated the deflection characteristic. Two kinds of the mirror devices composed of SU-8 containing Fe 2 O 3 (particle size: p.s.5μm) and Fe 3 O 4 (p.s.5μm) particles are fabricated and evaluated. The optical deflection angles of both devices are ±20° in a small current. Then, we confirmed the possibility to realize the low cost and large deflection angle polymer MEMS mirror using SU-8 containing magnetic particles.

This paper describes the possibility of the crystalline anisotropic etching of single-crystal silicon using a fully dry etching process. Conventionally, the crystalline anisotropic etching of silicon has been achieved only using specific wet solutions. In the proposed method, the anisotropic etching is made dominant by controlling the etching energy under specific dry etching conditions. The maximum crystalline anisotropic degree is 68% at present. It is expected that complicated three-dimensional microscale silicon structures can be formed by the fully dry process proposed in this paper.

We aim to achieve the phase-shift device which is a key component of two-dimensional Fourier spectrometer using the MEMS mirror fabricated by the micro fabrication technology. This mirror maintains parallel movement to the reference plane toward the vertical direction with a high precision. Therefore, in this study, the vertical electrostatic comb-drive actuator and displacement capacitive sensors were fabricated monolithically on one chip, and they were arrayed in 4 directions of the movable mirror. We fabricated the MEMS mirror that can move toward the vertical direction with sensing the tilting angle. As the result, we confirmed that the vertical comb-drive MEMS mirror with the sensing function for the phase-shift device could be realized.

In this paper, we propose a polymer MEMS mirror device which has the futures of the large deflection angle and the low cost fabrication. Many conventional MEMS mirror devices have been composed of Si wafer and, the expensive dry etching equipment has been necessary when etching the Si substrate. Then, we propose new composition and the novel fabrication method without the dry etching process by using the inexpensive glass substrate. Also, the torsion bar is composed of a photosensitive polymer that is a low rigid material and can be easily fabricated by the photolithography process. A multilayer wiring process is examined so that the low current actuation and the large deflection angle is attained. The fabricated device showed the large optical deflection angle of more than ±40 degrees at the current of ±16mA when the torsion bar length was 1800µm. The variation of the optical deflection angle was within 0.8 degrees at the 106 times repeatability test.

This paper reports a newly developed Si-MEMS integrated tactile imager that can detect tri-axial input force and ‘slip’ on the surface of the sensor in high spatial resolution (several hundreds micron). Tactile imaging is performed by a large area silicon membrane which is integrating sensor pixel array including strain gauge circuits. The new imager device presented in this paper has fingerprint-like patterns formed by Deep-RIE on the silicon sensor diaphragm. The patterns generate a rotational motion for horizontal axis input force, and it is similar with the role of human's fingerprints. Basic principle of the tactile imager was examined with FEM analysis for multi-axis input forces and the slip sensing ability. In addition, tri-axial load was successfully detected in each pixel by the new membrane sensor structure with low cross-axis sensitivities.

Silicon smart microchips with CMOS/MEMS technology are realized for intelligent sensing. In our developed chips, tow new type sensor chips are presented here. One is Si microprobe electrode array for using in the recording of neurons in the tissue. The probe array can be fabricated on IC chip, using standard IC process followed by a selective Si probe growth. Another one is pH image sensors successfully fabricated by using the CCD/CMOS image sensor technique, and real time imaging of a chemical reaction and pH distribution imaging was demonstrated.

This paper reports a new post-CMOS process to integrate thick (>10 mum) SOI MEMS devices after standard CMOS process, which requires only three additional photomask steps. The additional MEMS processes are not severe and critical for the integrated CMOS devices. In this technology, high aspect ratio SOI MEMS devices and CMOS integrated circuits are electrically connected with 'micro bridge interconnection' fabricated by batch processing. Metal interconnections are placed on oxide bridge structures that are connecting between electrically isolated CMOS areas and MEMS areas in active layer of thick SOI wafer in order to connect the MEMS electrodes to terminals in CMOS circuits. This fabrication technology can be applicable widely to high-dense integration of monolithic CMOS/MEMS on thick-SOI wafers.

In this chapter, we consider about novel applications of microvalves fabricated by MEMS technology in innovative micro devices and systems. By the remarkable advance of recent MEMS technology and demand to microvalve in the biotechnology field, microvalves realized by MEMS technology have been developed in the field at a stretch. MEMS microvalve is a digital fluidic control device to switch fluid flow between ON and OFF. MEMS microvalve is an analog fluidic control device to control fluid medium by analog control signal. According to the required function, operation mode and design of microvalves change. The most major application of microvalves in MEMS field is “Micro Total Analysis Systems (micro-TAS)”. MEMS microvalves are one of essential elements in micro-TAS to handle the liquid sample in micro channels. Figure 1 shows a concept diagram of a micro-TAS, integrated blood-test system, including plural microvalves [1] and integrated sensors [2]. In the system, microvalves are electrically controlled and used to switch liquid sample flow. Figure 2 shows the configuration of the blood test system showing the function of integrated microvalves. In the system, a mechanical pump is used to generate large pressure difference from atmosphere. Across each microvalve, pressure difference is applied, and microvalves are used only to open or close fluid flow circuit in the system. Controlling the electronic signal, the start timing of liquid sample flow are directly controlled. This is one of typical applications of microvalve in micro-TAS. Open image in new window FIGURE 1 Concept diagram of integrated blood-test system including plural microvalves and monolithically integrated sensors.

In this paper, a robust and sensitive silicon-MEMS tactile-imager which realizes scratch resistance and over-range protection is presented. This concept of tactile-imager can solve the fragility problem of sensitive structure without any protective materials, using backside silicon surface as contact-face. Also, backside contact-face is very suitable for tactile sensors since electronic terminals in the circuits can be removed from the contact-face side. Fabricated tactile-imager showed high robustness in scratch resistance tests with #120 emery-papers. In addition, over-ranged input (-1.68N) applied to 10 mum-silicon diaphragm was safely received. Robustness of the tactile-imager has been much improved using the concept without degradation of the original force sensitivity and spatial resolution.

This paper describes a device design, fabrication, experimental results, and mechanical strength for a multi functional device of neural behavioral analysis. The device has been fabricated with Si micro probe of 2 mum in diameter and SiO2 micro tube of 3.6 mum in outer diameter on circuit of MOSFETs, using standard IC process followed by a selective VLS growth and MEMS techniques. MOSFETs' performance on Si(lll) is 150 mV/decade of subthreshold factor and 1.2 V of threshold voltage after the fabrication process of probes and tubes. Penetration experiment into the gelatin was carried out for an application of neural recording devices.

In this paper, the concept and experimental results of microwave-powered silicon microsensors for distributed and embedded sensing applications are presented. This is the first report of a microsensor device integrated with RF-DC power converter on the same chip. The integrated sensors are fabricated by silicon-MEMS (Micro Electromechanical Systems) technology. This time, 'fuse-type strain detector', and 'water-leakage sensing switch' are fabricated by silicon micromachining. Driving power of the integrated microsensors is provided as a remote RF-electromagnetic wave at 1.29 GHz/1.45 GHz, and received at the rectenna circuit on the microsensor. In the fabrication experiments, high-performance surface mount devices (SMD) are integrated on the silicon microchip to realize the highest power efficiency. Mount holes of SMDs were formed by Deep-RIE of silicon with MEMS sensor structures without any additional process steps. Fabricated rectenna and sensors are successfully evaluated with LED mounted for signal output. The battery-less microsensor chip was successfully driven by a 10 W/1.29 GHz microwave power. Using a directional antenna as the power emission source, spread of microwave power is limited, and a longer distance of microwave power transmission is obtainable. The RF-powered microsensor node is very promising for various applications, and its conceptual prototype has been successfully fabricated.

In this paper, novel absorption photometry microchip with no reference solution is presented for the first time. The microchip solves the problem about reference solution. The novel microchip, which uses no reference solution, has sensors with three different optical path lengths. The microchip was fabricated using some MEMS process technique, for example silicon anisotropic etching with surfactant added TMAH solution to form 45-degree mirrors. Fabricated microchip was characterized with blood sample, and property of absorption photometry with no reference solution by combining plural optical path was investigated. By proposed method, absorption photometry microchip which is compatible in performance and convenience succeeded in development.