Papers - Takahashi, Hidetoshi

AlN cantilever for differential pressure sensor

Y Tomimatsu, H Takahashi, T Kobayashi, K Matsumoto, I Shimoyama, ...

2013 Joint IEEE International Symposium on Applications of Ferroelectric and … (IEEE)     336 - 339 2013

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The differential pressure sensors are used for various applications. In this work, a piezoelectric differential pressure sensor using an aluminum nitride (AIN) thin film cantilever is proposed to achieve high sensitivity and low power consumption. The dimensions of the cantilever are 1500 mu m x 1000 mu m x 2 mu m. The proposed sensor needs no power consumption in the AIN sensing element in principle. The sensor design was validated by measuring the performance of the sensor, which showed sensitivity of 8.2 mV/Pa from -20 Pa to 20 Pa

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A wake-up switch using a piezoelectric differential pressure sensor

Y Tomimatsu, H Takahashi, T Kobayashi, K Matsumoto, I Shimoyama, ...

2013 IEEE Eighth International Conference on Intelligent Sensors, Sensor … (IEEE)  1   23 - 26 2013

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This paper reports a wake-up switch using a piezoelectric differential pressure sensor in order to reduce the power consumption of a wireless sensor node. Air pressure change surrounding the sensor is detected by using a Pb(Zr,Ti)O-3(PZT) thin film cantilever with the dimension of 1500 mu m x 1000 mu m x 2 mu m. The sensor has high sensitivity with low power consumption due to its thin cantilever and low capacitance. The sensitivity was 2.4 mV/Pa from -30 Pa to 30 Pa. It was demonstrated that the fabricated sensor performed as a wake-up switch when pressure varies in 10 Pa with low power consumption.

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A triaxial tactile sensor without crosstalk using pairs of piezoresistive beams with sidewall doping

H Takahashi, A Nakai, N Thanh-Vinh, K Matsumoto, I Shimoyama

Sensors and Actuators A: Physical 199, 43-48 (Sensors and Actuators, A: Physical)  199   43 - 48 2013

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0924-4247

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This paper reports on a triaxial tactile sensor using piezoresistive beams. The sensor chip is composed of two pairs of sidewall-doped Si beams for shear stress sensing and one pair of surface-doped Si beams for normal stress sensing. The sizes of the shear- and pressure-sensing beams are 180 μm × 15 μm × 20 μm and 250 μm × 50 μm × 20 μm (length × width × thickness), respectively. The sensor chip is embedded in a PDMS sheet 10 mm × 10 mm × 2 mm in size. Because the simple beam structure can be fabricated easily, the proposed sensor is compatible with semiconductor device fabrication. The fabricated sensor was evaluated for normal and shear stress (0-400 kPa and 0-100 kPa, respectively). The responses of the corresponding beam pairs were found to be proportional to the magnitude of the applied stresses without the influence of the other stresses. The relationship between the angle of shear stress and the responses of each beam pair was also evaluated. Each beam pair detects only one axis's shear stress and showed little reaction to the other axes' shear stress. As a result, the proposed sensor can measure the three axial components of normal and shear stress independently. © 2013 Elsevier Ltd. All rights reserved.

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A piezoresistive cellular traction force sensor

UG Jung, H Takahashi, T Kan, K Matsumoto, I Shimoyama

Micro Electro Mechanical Systems (MEMS), 2013 IEEE 26th International …    927 - 930 2013

ISSN  1084-6999

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This paper presents a rigid piezoresistive sensor to measure cellular traction forces. The traction forces on a rigid substrate such as bone (10∼30 [GPa]) are still unknown. Our approach of the traction force measurement is not by an observation [1-4] but by a resistance change of the piezo-resistor due to the deformation of the rigid sensor (spring constant: 900 nN/μm). Because of its high sensitivity with sub-μN resolution, we were able to measure the traction forces on the rigid substrate. The stiffness of the proposed sensor was 10 times larger than that of previous works. We demonstrated that the traction forces generated by fibroblast were 0.7 μN when two cells adhered to the sensor. © 2013 IEEE.

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A piezoelectric cantilever-type differential pressure sensor for a low standby power trigger switch

Y Tomimatsu, H Takahashi, T Kobayashi, K Matsumoto, I Shimoyama, ...

Journal of Micromechanics and Microengineering 23 (12), 125023 (IOP PUBLISHING LTD)  23 ( 12 ) 125023 2013

Joint Work, Accepted,  ISSN  09601317

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This paper describes a piezoelectric differential pressure sensor using a cantilevered structure with dimensions of 1500 x 1000 x 2 mu m(3). A high degree of sensitivity is achieved without the power supply because only the base part of the cantilever is fixed and the piezoelectric material is used as a sensing element. The measurements indicate that the fabricated cantilever bends and a piezoelectric voltage was generated matching the piezoelectric theory for when a differential pressure is applied. The sensitivity to the applied differential pressure was 2.4 mV Pa-1 for a range between -30 Pa and 30 Pa. Additionally, it was also demonstrated that the sensor performs as a wake-up switch during the pressure shifts of 10 Pa with low-power consumption.

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A piezoelectric cantilever with a Helmholtz resonator as a sound pressure sensor

Y Tomimatsu, H Takahashi, T Kobayashi, K Matsumoto, I Shimoyama, ...

Journal of Micromechanics and Microengineering 23 (11), 114003  2013

A photoresponse-compensated parallel piezoresistive cantilever for cellular force measurements

UG Jung, K Kuwana, Y Ajiki, H Takahashi, T Kan, Y Takei, K Noda, ...

Journal of Micromechanics and Microengineering 23 (4), 045015 23 ( 4 ) 045015 2013

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0960-1317

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This paper describes a parallel piezoresistive cantilever that is composed of a force-sensing cantilever in addition to a reference cantilever for photoresponse compensation. Piezoresistive cantilevers have been applied in many cellular mechanical measurement studies because of their high sensitivity, high time resolution and ease of handling. However, the electrical resistance changes in response to the excitation light of the fluorescence microscope, which affects the cell measurements. We measured the I-V characteristics of a piezoresistive layer. These photoresponses occurred due to the internal photoelectric effect. We canceled the photoresponses using the reference cantilever. This paper demonstrates compensation of the cantilever photoresponse under irradiation at different angles, wavelengths and light intensities. As a result, the photoresponse could be decreased by 87%. © 2013 IOP Publishing Ltd.

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A barometric pressure sensor based on the air-gap scale effect in a cantilever

N Minh-Dung, H Takahashi, T Uchiyama, K Matsumoto, I Shimoyama

Applied Physics Letters 103 (14), 143505 (AMER INST PHYSICS)  103 ( 14 ) 143505 2013

Joint Work, Accepted,  ISSN  00036951

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The most common structure for a conventional barometric pressure sensor consists of a vacuum-sealed cavity and a diaphragm. However, we hypothesize that a simple structure with an unsealed cavity and an ultra-thin cantilever can provide more sensitive measurements. We produced a 300-nm-thick cantilever with a small spring constant, which made the cantilever sensitive to low pressures. We demonstrated that miniaturizing the air-gap of the cantilever enables the sensor to measure barometric pressure changes at a low pressure change rate with a high resolution, which was 1 Pa at 0.05 Hz, and for a gap size of 1.7 mu m. (C) 2013 AIP Publishing LLC.

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3P172 マイクロピラーアレイ上で成長したフィブロブラスト細胞の大きさと形状 (12. 細胞生物的課題, ポスター, 日本生物物理学会年会第 51 回 (2013 年度))

T Tsukagoshi, G Jung Uijin, H Takahashi, T Kan, K Matsumoto, ...

生物物理 53 (1), S240  2013

3-axis fingertip force during playing the string instrument

M Hori, M Hosono, H Takahashi, K Matsumoto, I Shimoyama

2013 Transducers & Eurosensors XXVII: The 17th International Conference on … (2013 Transducers and Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS and EUROSENSORS 2013)     2745 - 2748 2013

ISSN  9781467359818

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In this paper, we propose a measurement method of 3-axis fingertip force which works when playing a string instrument. A small and thin 3-axis tactile sensor was fabricated to attach to the first finger. The force sensing elements were formed within 1 mm×1 mm on the sensor chip, and the thickness of the sensor was 3 mm. A guitar was used as a string instrument. Using the proposed method, the 3-axis fingertip force was measured in two cases; (a) when the guitar string was held down incorrectly; (b) when the guitar string was held down properly. The data of the 3-axis tactile sensor and the guitar sound were recorded simultaneously. Comparing both cases, it was indicated that the number of the guitar sound's overtone spectra was increased when the string vibration did not propagate through the finger. This proposed method will develop a significant way to analyze the relationship between musicians' fingertip force and instrument sounds. © 2013 IEEE.

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Simultaneous detection of particles and airflow with a MEMS piezoresistive cantilever

H Takahashi, T Kan, K Matsumoto, I Shimoyama

Measurement Science and Technology 24 (2), 025107 (IOP PUBLISHING LTD)  24 ( 2 ) 025107 2013

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0957-0233

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This paper describes a particle and airflow sensor using a MEMS piezoresistive cantilever with the dimensions of 250 mu m x 200 mu m x 0.29 mu m. The sensor structure is simple and detects both the airflow velocity and particle collisions by measuring the fractional resistance change due to the cantilever bending. The signals of the airflow velocity and particle collisions can be simultaneously detected by distinguishing continuous and pulse responses. The sensitivity to the airflow velocity was 1.2 x 10(-3) (m/s)(-1) from 0 to 2.5 m s(-1). When a particle of 35 mu m diameter (Lycopodium) collided with the cantilever surface, the fractional resistance change varied with the collision. After the collision, reverberation occurred at 3 kHz, which was the same as the resonance frequency of the cantilever. The magnitude of the fractional resistance changes due to particle collision was proportional to the airflow velocity. The sensitivity to particle collision was 2.0 x 10(-3) (m/s)(-1) when the airflow velocity varied between 0 and 2.5 m s(-1).

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Regional 3-axis plantar forces during stair ascent

M Hori, H Takahashi, A Nakai, K Matsumoto, I Shimoyama

2013 IEEE 26th International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS))     1033 - 1036 2013

ISSN  10846999

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We proposed the measurement method of plantar force distribution during barefoot walking. 3-axis sensors were fabricated and attached on the sole of the foot. The sensors were so small, light and thin that we were able to measure the forces without interfering in the barefoot condition. Combining these sensors with wireless measurement system, we measured 3-axis plantar force distribution during level walking and stair ascent (Fig. 1). From these measurement results, we calculated zero moment point (ZMP): important index of robot walking. These results indicate that the proposed method can be suitable to analyze the mechanisms of barefoot walking. © 2013 IEEE.

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Quantitative evaluation of the influence of dopaminergic neuron on flapping locomotion

K Azuma, H Takahashi, T Kan, J Tanimura, K Ito, K Matsumoto, ...

2013 IEEE 26th International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS))     5 - 8 2013

ISSN  10846999

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This paper reports on quantitative evaluation of influence of dopamine neurons on the flight locomotion of a fruit fly (Drosophila menanogaster). The aerodynamic force was measured by MEMS triaxial forcesensor. We compared the aerodynamic force of the genetically modified flies whose dopamine neurons (DDCII) are functionally blocked with that of the wild type ones. The peak aerodynamic force generated by wild type flies was controlled smoothly. By contrast, the peak aerodynamic force generated by genetically modified flies showed rough fluctuation. The Peak variability of the wild type flies and genetically modified flies were 0.06 ± 0.04 and 0.18 ± 0.14 [-] (Average ± S.D.), respectively. The result indicated that the DDCII-expressing dopamine neurons were necessary to control their flapping flight. © 2013 IEEE.

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High sensitive 3D tactile sensor with the structure of elastic pyramids on piezoresistive cantilevers

N Thanh-Vinh, N Binh-Khiem, K Matsumoto, I Shimoyama

2013 IEEE 26th International Conference on Micro Electro Mechanical Systems …  2013

MEMS microphone with a micro Helmholtz resonator

H Takahashi, A Suzuki, E Iwase, K Matsumoto, I Shimoyama

Journal of Micromechanics and Microengineering 22 (8), 085019 (IOP PUBLISHING LTD)  22 ( 8 ) 085019 2012

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0960-1317

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This paper reports on the development of a micro electro mechanical system microphone consisting of a piezoresistive cantilever and a micro HR (Helmholtz resonator) for use as an ultrasonic proximity sensor. The resonance frequency of the HR was designed to be equal to that of the cantilever. Therefore, the HR increases the sensitivity of the microphone to ultrasonic waves. The dimensions of the fabricated HR and the cantilever are 1.2 mm x 1.2 mm x 0.6 mm and 130 mu m x 40 mu m x 0.3 mu m, respectively. At a resonance frequency of 22.6 kHz, the cantilever with the HR detected ultrasonic waves with 14 times greater sensitivity than that of the cantilever without the HR. We demonstrated that the fabricated sensor is capable of measuring distances between 0.5 and 6.0 m.

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Differential pressure sensor using a piezoresistive cantilever

H Takahashi, NM Dung, K Matsumoto, I Shimoyama

Journal of Micromechanics and Microengineering 22 (5), 055015 (IOP PUBLISHING LTD)  22 ( 5 ) 055015 2012

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0960-1317

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This paper reports on a differential pressure sensor using a piezoresistive cantilever with the dimensions of 125 mu m x 100 mu m x 0.3 mu m. The sensor has a higher sensitivity than a traditional diaphragm sensor because of the three free edges of the cantilever. The measured results indicated that the fabricated cantilever bent according to theory when differential pressure was applied. The sensitivity and resolution of the differential pressure were 3.2 x 10 (4) Pa (1) and 0.02 Pa from -20 Pa to 20 Pa, respectively.

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Differential pressure measurement of an insect wing using a MEMS sensor

H Takahashi, K Matsumoto, I Shimoyama

Complex Medical Engineering (CME), 2012 ICME International Conference on …    349 - 352 2012

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An insect can perform flight maneuvers such as hovering and snap turns. There have been many methods such as digital particle image velocimetry (DPIV) or kinematic analysis using robotic wings modeled on insects to investigate the aerodynamic force. The aerodynamic force is derived from the differential pressure between the upper and lower surfaces of its wings. The actual aerodynamic force on real insect wings has never been measured directly during free flight. Here we show direct measurement of differential pressure acting on the wing surface of a real insect during free flight. A micro differential pressure sensor was fabricated by utilizing micro electro mechanical systems (MEMS) and fixed to a butterfly (Papilio protenor) wing. The size and weight of the sensor chip are 1.0 mm x 1.0 mm x 0.3 mm and 0.7 mg, respectively. The differential pressures were measured during takeoff. From the measured differential pressure distribution, aerodynamic force was calculated. The maximum aerodynamic force generated on the wings was 3 times larger than the gravity acting on the body. © 2012 IEEE.

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Differential pressure distribution measurement with an MEMS sensor on a free-flying butterfly wing

H Takahashi, H Tanaka, K Matsumoto, I Shimoyama

Bioinspiration & biomimetics 7 (3), 036020 (IOP PUBLISHING LTD)  7 ( 3 ) 036020 2012

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1748-3182

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An insect can perform various flight maneuvers. However, the aerodynamic force generated by real insect wings during free flight has never been measured directly. In this study, we present the direct measurement of the four points of the differential pressures acting on the wing surface of a flying insect. A small-scale differential pressure sensor of 1.0 mm x 1.0 mm x 0.3 mm in size was developed using microelectromechanical systems (MEMS) and was attached to a butterfly wing. Total weight of the sensor chip and the flexible electrode on the wing was 4.5 mg, which was less than 10% of the wing weight. Four points on the wing were chosen as measurement points, and one sensor chip was attached in each flight experiment. During takeoff, the wing's flapping motion induced a periodic and symmetric differential pressure between upstroke and downstroke. The average absolute value of the local differential pressure differed significantly with the location: 7.4 Pa at the forewing tip, 5.5 Pa at the forewing center, 2.1 Pa at the forewing root and 2.1 Pa at the hindwing center. The instantaneous pressure at the forewing tip reached 10 Pa, which was ten times larger than wing loading of the butterfly.

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CNT-FET gas sensor using a functionalized ionic liquid as gate

N Kiga, Y Takei, A Inaba, H Takahashi, K Matsumoto, I Shimoyama

2012 IEEE 25th International Conference on Micro Electro Mechanical Systems … (IEEE)     796 - 799 2012

ISSN  1084-6999

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We propose a gas sensor using combination of carbon nanotubes (CNTs) and ionic liquid (IL). In our research, we used IL, 1-ethyl-3-methyl imidazolium tetrafluoroborate ([EMIM][BF4]) which specially absorbs CO2 / NH3, and polymer, polyethyleneimine (PEI) which absorbs CO2. This IL or the mixture of IL and PEI dropped on the CNT-FET were applied as a CNT-FET IL-gate and a surface modification material of CNTs. When the IL absorbs specific gases, the ion types and concentrations change. We measured the change of CNT I-V property by applying a voltage to the IL-gate to attract the ions onto the CNT surface.

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Carbon dioxide detection by surface plasmon resonance with ionic liquid

K Ishizu, T Kan, Y Takei, H Takahashi, K Matsumoto, I Shimoyama

2012 IEEE 25th International Conference on Micro Electro Mechanical Systems … (IEEE)     784 - 787 2012

ISSN  1084-6999

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We propose a carbon dioxide (CO2) gas sensor using an SPR (surface plasmon resonance) sensing scheme with an ionic liquid. In this study, we used [EMIM][BF4] as an ionic liquid. The permittivity of the liquid increased when it absorbs CO2 gas. This permittivity change was detected by the SPR sensing scheme. We confirmed that our proposed sensor was able to measure CO2 gas with a concentration as low as 700 ppm.

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