Tsukuba, Japan
Tsukuba, Japan

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Takamatsu S.,Macro Center | Imai T.,Macro Center | Yamashita T.,Macro Center | Kobayashi T.,Japan National Institute of Advanced Industrial Science and Technology | And 2 more authors.
Proceedings of IEEE Sensors | Year: 2011

We proposed flexible fabric keyboard which consists of conductive polymer of PEDOT:PSS-coated fibers, standard Micro Control Unit (MCU) with capacitance measurement circuits and personal computer (PC). In the sensor structure, PEDOT:PSS and UltraViolet(UV) -curable adhesive-coated fibers were woven as wefts and warps. The conductive polymer and insulating polymer coating technique was developed to form functional material on enough long fibers to weave fabric with. The weaving with automatic looming machine was employed, forming 1.2 m x 3 m sensor fabric. The sensors could detect human touch by measuring capacitance change between human fingers. The values of capacitance change under touch input ranges from 1.0 to 2.0 pF which is able to be detected by conventional capacitance meters that were integrated in MCUs. By using 9 by 3 touch sensors, keyboard was constructed and the demonstration of inputting character was made. © 2011 IEEE.


Yamashita T.,Macro Center | Takamatsu S.,Macro Center | Takamatsu S.,Japan National Institute of Advanced Industrial Science and Technology | Miyake K.,Macro Center | And 3 more authors.
Japanese Journal of Applied Physics | Year: 2012

This article presents an improvement in the stability and durability of the electrical contacts employed in flexible devices. A coating of poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate) in form of a solid conductive layer on a silicone elastomer structure is employed in creating an electrical circuit embedded into the fabric of a woven electronic textile, where the coating serves as an electrical contact between weft and warp ribbons. When the contact load increases to 1 mN, then, due to the flexibility of the structure, an electric current begins to flow through the circuit. The structure can sextuplicate the life of the electrical contact. © 2012 The Japan Society of Applied Physics.


Yamashita T.,Macro Center | Takamatsu S.,Macro Center | Takamatsu S.,Japan National Institute of Advanced Industrial Science and Technology | Kobayashi T.,Macro Center | And 3 more authors.
IEEJ Transactions on Sensors and Micromachines | Year: 2013

We developed all polymer piezoelectric film which consists of polyethylene terephthalate (PET) film substrate, conductive polymer poly(3, 4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) electrodes, and polyvinylidene difluoride (PVDF) piezoelectric film in order to achieve the low resonance frequency of energy harvesting device. Existing piezoelectric films have been deposited on rigid silicon or inorganic materials which lead to high resonance frequency and low efficiency of energy generating under low frequency of human or animal motions. Therefore, we developed all polymeric piezoelectric films on very soft PET films. To deposit PVDF film on PEDOT:PSS coated PET, low temperature coating process using low boiling temperature solvent (methyl ethyl ketone) and annealing method (under 150°C) was developed. Developed film achieved low frequency of 81 Hz. © 2013 The Institute of Electrical Engineers of Japan.


Yamashita T.,Macro Center | Takamatsu S.,Macro Center | Takamatsu S.,Japan National Institute of Advanced Industrial Science and Technology | Miyake K.,Macro Center | And 3 more authors.
IEICE Electronics Express | Year: 2012

This paper presents an innovation and fabrication process of electrical contact structure using reel-to-reel continuous systems in flexible device technology. A coating of poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate) as a solid conductive layer deposited on silicone elastomer structures are employed in composing the electrical circuit through a large area of woven electronic textile (etextile), and functions as the electrical contact between weft and warp (interlaced) fiber ribbons. From the resistance measurements using flexible sheets by weaving PET ribbon cable, the structures enhance the durability, flexibility and stability of electrical contact in the woven e-textile better than those of the ribbons without it. © IEICE 2012.


Naito T.,Macro Center | Konno N.,Macro Center | Tokunaga T.,Macro Center | Itoh T.,Macro Center | Itoh T.,Japan National Institute of Advanced Industrial Science and Technology
Microsystem Technologies | Year: 2013

This paper reports a local ambient gas control technology for atmospheric MEMS processes, especially plasma processes, using a new local ambient gas control head. First, the local ambient gas control with this head was investigated by a computational fluid dynamics code. After confirmation of the safe evacuation and the feasible cleanness level, which is comparable to the impurity level in semiconductor grade gas (below 10 ppm), a prototype apparatus was fabricated based on the simulation results. Measuring gas distribution by a gas analyzer, a O2 meter and a dew point meter, the local ambient gas control was confirmed experimentally. Next, H2 plasma generation was achieved in open air with H2 concentrations of 0-100 % even above the explosive limit in air (4.1 %) safely. In addition, Cu reduction and SiO2 etching by H2 plasma were demonstrated in open air. These results show high potential of our local ambient gas control technology for atmospheric MEMS processes. © 2013 Springer-Verlag Berlin Heidelberg.


Naito T.,Macro Center | Konno N.,Macro Center | Tokunaga T.,Macro Center | Itoh T.,Japan National Institute of Advanced Industrial Science and Technology
Proceedings of IEEE Sensors | Year: 2012

We investigated the doping properties of polycrystalline silicon (poly-Si) deposited by atmospheric pressure plasma enhanced chemical transport and fabricated a strain gauge with the doped poly-Si film. The doping was done by the chemical transport of the dopant in Si sources. The electronic properties reveal that most of the dopants were transported as Si atoms. A strain gauge was fabricated with the doped poly-Si film. All processes were carried out below 350 °C. The strain gauge showed the good linearity of the resistance change rate with the stress. These results indicate that our Si deposition method has adequate potential for low temperature MEMS processes. © 2012 IEEE.


Yamashitd T.,Macro Center | Takamatsu S.,Macro Center | Takamatsu S.,Japan National Institute of Advanced Industrial Science and Technology | Kobayashi T.,Macro Center | And 3 more authors.
2013 Transducers and Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS and EUROSENSORS 2013 | Year: 2013

This paper reports a novel fabrication process of an all polymer piezoelectric film which consists of polyethylene terephthalate (PET) film substrate, conductive polymer poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) electrodes, and ferroelectric polymer poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE) using reel-to-reel continuous fiber processing systems. Existing piezoelectric films have been deposited on rigid silicon or inorganic materials which lead to high resonance frequency and low efficiency of energy generating under low frequency of human or animal motions. Therefore, we developed all polymeric piezoelectric films on very soft PET films. To deposit P(VDF-TrFE) film on PEDOT:PSS coated PET, low temperature coating process using low boiling temperature solvent (acetone) and annealing method (under 150°C) was developed. © 2013 IEEE.


Yamashita T.,Macro Center | Miyake K.,Macro Center | Miyake K.,Japan National Institute of Advanced Industrial Science and Technology | Itoh T.,Macro Center | Itoh T.,Japan National Institute of Advanced Industrial Science and Technology
Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) | Year: 2012

This paper reported a novel innovation of electrical contact structure in flexible device technology. The poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate) coated silicone elastomer structure is employed in composing the electrical circuit through a large area of woven electronic textile (e-textile), and functions as the electrical contact between weft and warp (interlaced) fiber ribbons. The structure enhances the durability, flexibility and stability of electrical contact in the woven e-textile better than those of the ribbons without it. © 2012 IEEE.


Yang Z.,Japan National Institute of Advanced Industrial Science and Technology | Zhang Y.,Macro Center | Zhang Y.,Japan National Institute of Advanced Industrial Science and Technology | Itoh T.,Macro Center | Itoh T.,Japan National Institute of Advanced Industrial Science and Technology
Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) | Year: 2013

A flexible implantable micro temperature sensor has been proposed and fabricated on a polymer capillary by surface micromachining. The dynamic temperature response of the sensor when used in the hyperthermia is simulated and analyzed. The micro sensor has been successfully fabricated by our developed cylindrical projection lithography system. Platinum film is used as the sensing element material considering its good stability and linear resistance- temperature relationship. The temperature coefficient of resistance (TCR) and the current-voltage curves of the sensor prototype have been tested and evaluated. The test average TCR value derived from the fitted line is 0.0035/°C, which has a good agreement with industry standard value of the bulk Pt resistor sensor. The present flexible micro temperature sensor could be widely used as a precise implantable monitoring device in various biomedical applications. © 2013 IEEE.


Lu Y.,Macro Center | Zhang Y.,Macro Center | Zhang Y.,Japan National Institute of Advanced Industrial Science and Technology | Lu J.,Macro Center | And 6 more authors.
Journal of Micromechanics and Microengineering | Year: 2010

This paper proposes a new three-dimensional (3D) photolithography technology for a high-resolution micropatterning process on a fiber substrate. A brief review on the lithography technology of the non-planar surface is also presented. The proposed technology mainly comprises the microfabrication of the 3D exposure module and the spray deposition of thin resist films on the fiber. The 3D exposure module is successfully prepared by the wet etching of a quartz substrate and the projection exposure method. The chief advantages of the 3D exposure module are long service life, low cost, narrow print gap and thus high resolution. A novel spray coating system has been developed for the preparation of uniform and thin resist films on the fibers, which are necessary for the high-resolution micropatterning process. The spray deposition process on the 125 μm in-diameter optical fiber has been systematically investigated. The viscosity and volatility of the resist solutions have complicated effects because the spray-coating deposition process on the fiber mainly consisted of the impinging region. The uniform and thin resist film down to 1 μm thick had been successfully achieved. Fine patterns with the line width down to 6 μm were successfully formed on the optical fiber by using the microfabricated exposure module. Preliminary photolithography experiments confirmed that the new 3D photolithography technology is one attractive low-cost solution to the integration of micro transducers onto the fibers for various applications. The 3D exposure module could also enable the continuous photolithography process on the fibers. © 2010 IOP Publishing Ltd.

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