論文 - 田口　良広

Quadrant kirigami-type electrothermal MEMS actuator with multi-degree-of-freedom morphing capability

Tsutsui T., Taguchi Y., Hashimoto M.

Journal of Micromechanics and Microengineering 35 （ 2 ）  2025年02月

ISSN  09601317

　概要を見る

Kirigami design principles have been widely applied to develop thermally responsive shape-morphing devices across various scales. However, the multi-degree-of-freedom (multi-DoF) morphing capabilities of microelectromechanical-systems (MEMS)-scale kirigami devices under localized Joule heating remain largely unexplored. This paper presents a quadrant kirigami-type electrothermal MEMS actuator with multi-DoF morphing capabilities, demonstrating both one-dimensional piston motion and two-dimensional (2D) tilting motion. The actuator, fabricated using surface and bulk micromachining techniques, features four independent electrical circuits, creating four electrothermally separated quadrants within the MEMS-scale kirigami structure. The temperature distribution within each quadrant of the actuator, subjected to localized Joule heating, was experimentally examined using thermography, revealing distinct temperature contrasts. The actuator demonstrated multi-DoF morphing capabilities, achieving a 2D tilting angular displacement of approximately 10° at 70 mW and a vertical piston displacement of 1.5 mm at 135 mW. These experimental results validate that the electrothermal quadrant design, leveraging localized Joule heating, enhances the DoF morphing capabilities of kirigami-type electrothermal MEMS actuators.

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Direct writing of graphitic carbon/polydimethylsiloxane bimorph thermal microactuator via two-photon polymerization and laser-induced graphitization

Yu Yamashita, Yasuko Tanaka, Chen Tianzhou, Yoshihiro Taguchi, and Masaaki Hashimoto

Mechanical Engineering Journal 2024年

査読有り

　概要を見る

(Accepted)

2光子マイクロ光造形とフェムト秒レーザアブレーションを用いた熱駆動ソフトマイクロアクチュエータ作製の基礎検討

陳天州, 田口良広, 橋本将明

熱物性 2024年

査読有り

Bimorph Thermal Microactuator Fabricated by Additive and Subtractive Femtosecond Laser Processing

Chen T., Taguchi Y., Hashimoto M.

International Conference on Optical MEMS and Nanophotonics 2024年

ISSN  21605033

　概要を見る

This study presents an additive and subtractive fabrication method for a bimorph thermal microactuator using TPP 3D printing and femtosecond laser ablation. First, a microcantilever with a thickness of 30 μm was printed by TPP 3D printing. Second, femtosecond laser ablation was utilized to reduce the thickness to 15 μm, which facilitated the creation of a bimorph structure. The cantilever-shaped bimorph microactuator demonstrated stable cyclic actuation, achieving a tip displacement of 11.5 μm through laser heating.

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Design of focus-tunable freeform microlens printed on kirigami MEMS actuator

Matsuoka Y., Tsutsui T., Taguchi Y., Hahsimoto M.

International Conference on Optical MEMS and Nanophotonics 2024年

ISSN  21605033

　概要を見る

This study proposes the design of a focus-tunable freeform microlens printed on a MEMS actuator. The proposed freeform microlens, designed with its varying surface curvature along the azimuthal direction, can adjust its focal length through the tilt motion of the MEMS actuator. The designed freeform microlens was printed onto a glass substrate, and demonstrated focus tunability ranging from 0.31 mm to 3.72 mm.

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Fabrication and characterization of VO<inf>2</inf> kirigami electrothermal MEMS actuator

Tsutsui T., Taguchi Y., Hashimoto M.

International Conference on Optical MEMS and Nanophotonics 2024年

ISSN  21605033

　概要を見る

A kirigami electrothermal MEMS actuator using the phase transition material VO2 has been proposed. This paper reports the fabrication process and mechanical characteristics of the actuator. The actuator was fabricated by MEMS processes with VO2 annealing method. Through the environmental heating, the actuator exhibited the bi-directional actuation due to the thermal expansion and phase transition shrinkage of VO2, resulting in a net downward displacement of 219.5 μm.

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Fabrication of a Soft Photothermal Microactuator Using Two-photon Polymerization and Vacuum Filling

Tanaka K., Taguchi Y., Hashimoto M.

International Conference on Optical MEMS and Nanophotonics 2024年

ISSN  21605033

　概要を見る

A fabrication method of a soft photothermal microactuator using two-photon polymerization and vacuum filling is proposed. Proposed microactuator was fabricated through two processes: A two-photon polymerization (TPP) and a composite injection by a vacuum filling. First, a PDMS microcantilever with a microfluidic channel was printed by TPP. Second, a PDMS composite containing thermally expandable microspheres was filled in the microfluidic channel. To validate this method, a microactuator with dimensions of 1 mm × 130 μm × 100 μm was fabricated. We demonstrated the ability of the soft photothermal microactuator to produce displacement of approximately 50 μm by laser heating.

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Additive manufacturing method of electrothermal 4D bimorph microactuator

Hashimoto M., Sato T., Taguchi Y.

Sensors and Actuators A: Physical 356 （ 114348 ）  2023年06月

研究論文（学術雑誌）, 共著, 最終著者, 責任著者, 査読有り

　概要を見る

This paper presents an additive manufacturing method of an electrothermally controllable 4D-printed bimorph microactuator. We fabricated an electrothermal 4D bimorph microactuator equipped with an electrical heater through a two-step additive process: two-photon polymerization (TPP) 4D printing and liquid metal microfluidic injection. First, a 3D thermal bimorph microstructure including a microchannel was built using TPP printing. Second, the printed microstructure was electrically wired by injecting a liquid metal into the microchannel. To validate this method, we fabricated and characterized a vertical-spiral-shaped electrothermal 4D rotary microactuator with a large angular displacement. The fabricated electrothermal microactuator successfully controlled its temperature and angular displacement via electricity. Furthermore, we experimentally demonstrated the unique ability of the electrothermal 4D bimorph microactuator to produce repeatable large angular displacements of more than 10° at 386 mV. Accordingly, the proposed method is expected to enhance the spatial design freedom of electrothermal microactuators with potential applications in soft microrobotics.

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Design of Bi-Directional VO<inf>2</inf>-Kirigami Electrothermal Microactuator with Millimeter Large Stroke

Hashimoto M., Tsutsui T., Taguchi Y.

2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems, Transducers 2023    741 - 744 2023年

　概要を見る

This paper reports the design of a bi-directional VO2-KIRIGAMI electromechanical microactuator with a large millimeter stroke and low power consumption. Using Finite Element Method (FEM) simulation, it has been demonstrated that the proposed VO2-KIRIGAMI design can achieve a remarkable stroke of 2.2 mm with a power consumption of only 54 mW. This design study has enabled the application of electrothermal microactuators in long-range lens focusing for endoscopic procedures.

ミリ長ストローク・低電力 熱駆動切り紙MEMS アクチュエータの開発 ―薄膜バイモルフの熱・機械応答特性―

橋本　将明, 田口　良広

熱物性 34 （ 4 ） 109 - 116 2020年07月

研究論文（学術雑誌）, 共著, 最終著者, 責任著者, 査読有り

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Circular pyramidal kirigami microscanner with millimeter-range low-power lens drive

Hashimoto M., Taguchi Y.

Optics Express （Optics Express）  28 （ 12 ） 17457 - 17467 2020年06月

　概要を見る

© 2020 Optical Society of America under. This paper proposes an electrothermally-actuated circular pyramidal kirigami microscanner with a millimeter-range low-power lens drive for endoscopic biomedical applications. A variation of Japanese origami art, kirigami involves creation of out-of-plane structures by paper cutting and folding. The proposed microscanner is composed of freestanding kirigami film on which the spiral-curved thermal bimorphs are strategically placed. The kirigami microscanner is electrothermally transformed into an out-of-plane circular multistep pyramid by Joule heating. The circular pyramidal kirigami microscanner on a small footprint of 4.5 mm 4.5 mm was fabricated by microelectromechanical system processes. A large four-step pyramidal actuation was successfully demonstrated, and a large 1.1-mm lens travel range at only 128 mW was achieved.

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Design and fabrication of a kirigami-inspired electrothermal MEMS scanner with large displacement

Hashimoto M., Taguchi Y.

Micromachines （Micromachines）  11 （ 4 ）  2020年04月

　概要を見る

© 2020 by the authors. Large-displacement microelectromechanical system (MEMS) scanners are in high demand for a wide variety of optical applications. Kirigami, a traditional Japanese art of paper cutting and folding, is a promising engineering method for creating out-of-plane structures. This paper explores the feasibility and potential of a kirigami-inspired electrothermal MEMS scanner, which achieves large vertical displacement by out-of-plane film actuation. The proposed scanner is composed of film materials suitable for electrothermal self-reconfigurable folding and unfolding, and microscale film cuttings are strategically placed to generate large displacement. The freestanding electrothermal kirigami film with a 2 mm diameter and high fill factor is completely fabricated by careful stress control in the MEMS process. A 200 μm vertical displacement with 131 mW and a 20 Hz responsive frequency is experimentally demonstrated as a unique function of electrothermal kirigami film. The proposed design, fabrication process, and experimental test validate the proposed scanner's feasibility and potential for large-displacement scanning with a high fill factor.

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Development of a robust autofluorescence lifetime sensing method for use in an endoscopic application

Ito S., Hashimoto M., Taguchi Y.

Sensors (Switzerland) （Sensors (Switzerland)）  20 （ 7 ）  2020年04月

　概要を見る

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Endoscopic autofluorescence lifetime imaging is a promising technique for making quantitative and non-invasive diagnoses of abnormal tissue. However, motion artifacts caused by vibration in the direction perpendicular to the tissue surface in a body makes clinical diagnosis difficult. Thus, this paper proposes a robust autofluorescence lifetime sensing technique with a lens tracking system based on a laser beam spot analysis. Our optical setup can be easily mounted on the head of an endoscope. The variation in distance between the optical system and the target surface is tracked by the change in the spot size of the laser beam captured by the camera, and the lens actuator is feedback-controlled to suppress motion artifacts. The experimental results show that, when using a lens tracking system, the standard deviation of fluorescence lifetime is dramatically reduced. Furthermore, the validity of the proposed method is experimentally confirmed by using a bio-mimicking phantom that replicates the shape, optical parameters, and chemical component distribution of the cancerous tissue.

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Kirigami-inspired Electrothermal Actuator for Motion Tracking Blood Flow Measurement

Hashimoto M., Taguchi Y.

International Conference on Optical MEMS and Nanophotonics （International Conference on Optical MEMS and Nanophotonics）  2019-July   152 - 153 2019年07月

　概要を見る

© 2019 IEEE. A large stroke electrothermal MEMS actuator with small device footprint and low driving voltage has been proposed for motion tracking blood flow measurement. This paper reports this kirigami-inspired device design and simulation results of the proposed actuator.

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Nanoparticle sorting technique using laser induced dielectrophoresis with phase modulated interference

Miura D., Taguchi Y., Nagasaka Y.

International Conference on Optical MEMS and Nanophotonics （International Conference on Optical MEMS and Nanophotonics）  2019-July   100 - 101 2019年07月

　概要を見る

© 2019 IEEE. A novel nanoparticle sorting technique using the laser-induced dielectrophoresis (LIDEP) and phase modulated interference has been developed. In this paper, a proposed method of nanoparticle sorting and fabrication of microfluidic device are reported, and the validity of a method is discussed.

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Rapid and label-free sensing of intermolecular interactions using compact optical diffusion sensor

Kamata M., Takaba Y., Taguchi Y., Nagasaka Y.

International Journal of Heat and Mass Transfer （International Journal of Heat and Mass Transfer）  133   73 - 79 2019年04月

　概要を見る

© 2018 The Authors Diffusion sensors for nano-sized materials dispersed in a solution are promising tools for investigating intermolecular interactions, which is an important task in a wide range of industrial and biomedical fields, such as the development of therapeutic products and diagnostic tools. For the development of the sensor applicable to point-of-care testing, an optofluidic sensor was proposed. The proposed sensor realizes a simple measurement in a short time using microscale manipulation by interferometrically-induced dielectrophoresis and optical detection. In this paper, the applicability of the proposed sensor to distinguish nanoscale differences in size was confirmed by measurements on a solution containing size-certified plain nano-beads (51 nm, 100 nm, 203 nm, 216 nm and 240 nm) with evaluating the uncertainties of the proposed sensor. Furthermore, measurements using 200-nm beads coated with functional groups (NH2 and biotin) and proteins (streptavidin and bovine serum albumin) demonstrated the applicability to the investigation of intermolecular interactions.

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Non-contact optical hand-held viscosity sensor with incident angle and irradiation timing controls

Eguchi M., Taguchi Y., Nagasaka Y.

Optics Express （Optics Express）  26 （ 26 ） 34070 - 34080 2018年12月

　概要を見る

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. This paper proposes a novel optical hand-held viscosity sensor based on a laser-induced capillary wave method that can be used as a noncontact and quick in situ viscometry of liquid samples. Incident angle and irradiation timing control systems were integrated into the hand-held viscosity sensor to robustly measure viscosity by detecting the optical signal in a hand-held condition. We report the stability evaluation of these systems under the hand-held condition. Finally, the proposed sensor’s applicability to the hand-held viscometer was confirmed by measuring the viscosity distribution that the temperature gradient of the liquid sample caused.

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Coding two-dimensional patterns into mode spectrum of silicon microcavity covered with a phase-change film

Sobhi F., Kihara Y., Kataiwa D., Taguchi Y., Kuwahara M., Saiki T.

Applied Physics A: Materials Science and Processing （Applied Physics A: Materials Science and Processing）  124 （ 11 ）  2018年11月

　概要を見る

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. In the present study, we propose a new approach for coding two-dimensional patterns (spatial information or images) into mode spectra of a silicon microcavity. Electric field distributions associated with each cavity mode generated by the microcavity provide a basis (dictionary) for image encoding. The cavity is covered with a layer of phase-change material (Ge2Sb2Te5; GST), which enables the electric field distribution to be memorized and the images to be encoded into absorption spectra via the difference in the refractive index between the crystalline and amorphous phases. In numerical simulations, a clear modification of the absorption spectra of the GST layer upon partial crystallization was demonstrated. We fabricated silicon microcavities covered with a GST layer and confirmed that spectral features originating from individual cavity modes can be greatly modified upon phase change.

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A Study on a Single Cell Thermometry Using Fluorescence in Near-Field

Tamura A., Taguchi Y.

International Conference on Optical MEMS and Nanophotonics （International Conference on Optical MEMS and Nanophotonics）  2018-July 2018年09月

　概要を見る

© 2018 IEEE. An in-vitro method for temperature mapping of a single cell using fluorescence in near-field and a membrane window is developed. In this paper, we report analytical results which indicate the feasibility of our method.

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Plastic Based Microfluidic Chip for Optical Diffusion Sensor Using Laser-Induced Dielectrophoresis

Okuwaki T., Kamata M., Taguchi Y., Nagasaka Y.

International Conference on Optical MEMS and Nanophotonics （International Conference on Optical MEMS and Nanophotonics）  2018-July 2018年09月

　概要を見る

© 2018 IEEE. A novel plastic based microfluidic chip for the optical diffusion sensor using the laser-induced dielectrophoresis is designed and fabricated. The diffusion signal of the first-order diffracted light was detected by using our proposed microfluidic chip.

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