Film Actuator Research Articles

Development of transparent thin film speaker and its application for active sound transmission control through windows

Homes close to airports and highways in major metropolitan areas suffer from serious noise problems. Typically, windows constitute the primary path through which noise enters a home. As an effective method for attenuating low frequency noise, active noise cancellation approach has drawn increasing interest. A small voice coil actuator can be used to vibrate a glass panel and achieve significant reduction in noise transmission at its location. However, global noise cancellation over the entire panel can not be achieved with such a single point actuator. Using multiple voice coil actuators is also not practical, since several actuators on a windowpane would destroy the aesthetics of the window. This necessitates the development of thin film actuators that can provide distributed canceling sound over the entire surface of large sized glass panels. The need of transparence for the windows application poses a great challenge to the development of such thin film actuators. In this paper, transparent thin film speakers are developed, based on the use of carbon nanotubes for conductive films that are coated on polzerized PVDF films. Preliminary experimental results show that the transparent thin film speaker has the potential to be a promising solution for the ANC windows.

Optimal design of smart carriage arm in magnetic disk drive for vibration suppression

In hard disk drives, vibration suppression is very important to boost the performance of information-processing equipment. It has been expected that technology of smart structure will contribute to the development of small and light-weight mechatronics devices with the required performance. The smart structure is composed of the piezoelectric film sensor and actuator in order to reduce the structural vibration. The placement of the piezoelectric actuator and H2 control system are simultaneously optimized based on genetic algorithm to improve the effect on the vibration suppression. It has been verified by some applications with a plate structure and a magnetic disk drive that an enhanced performance for the vibration suppression can be achieved by the proposed optimal design method.

Free-standing polypyrrole actuators with response rate of 10.8% s −1

A free-standing polypyrrole (PPy) film actuator without any additional electrode or metal backing, prepared electrochemically from an aromatic ester solution of tetra- n-butylammonium bis(trifluoromethanesulfonyl)imide (TBATFSI), exhibited up to 29% electrochemical strain, and a peak response rate of 10.8% s −1 in an H 2O/propylene carbonate (PC) solution of LiTFSI. This is the very first time both large electrochemical strains and fast response rates were achieved in the conducting polymer actuators. The large and fast electrochemical deformation resulted from the fact that the PPy film doped with large TFSI anions swelled in PC such that TFSI can insert and expel the PPy film easily, and that a high ionic conductivity in H 2O/PC solution enabled to move TFSI quickly.

716 円形噴流の制御に関する研究 : PVDFフィルムアクチュエータによる軸方向励起渦の挙動(OS7-4 噴流及びせん断流の構造と制御(励起噴流),OS7 噴流及びせん断流の構造と制御,オーガナイズドセッション)

716 円形噴流の制御に関する研究 : PVDFフィルムアクチュエータによる軸方向励起渦の挙動(OS7-4 噴流及びせん断流の構造と制御(励起噴流),OS7 噴流及びせん断流の構造と制御,オーガナイズドセッション)

High Responsiveness Induced by Palladium Deposition on Thin Film Actuator of LaNi<SUB>5</SUB> Hydrogen Storage Alloy

The unimorph actuator of the LaNi5 thin film deposited on polyimide substrates can be expected as a sensor and/or a controller of hydrogen gas flux in various hydrogen-related devices, since controlling the hydrogen concentration in the film by pressure change drives this actuator reversibility. In this study, the effect of the palladium deposition was investigated on the mechanical response of this thin film actuator. It was shown that the initiating time (incubation period) for the actuation to be measured after hydrogen gas exposure was reduced from 100 to 1 s by the palladium deposition. This significantly improvement of the mechanical response was attributed to the change in the rate determining steps: the dissociation of hydrogen gas molecules on the sample surface for the sample without palladium deposition, and hydrogen diffusion in the LaNi5 film for the palladium deposited sample. It was also suggested that the high permeability of hydrogen in palladium film at room temperature resulted in the high responsiveness.

1P2-S-083 高分子電解質膜アクチュエータ(ICPF)の位置決め制御への応用 : 第2報:Au-NF115ICPFの位置決め制御特性と,残留変位の方向に及ぼす稼動イオンの影響(アクチュエータの機構と制御3,生活を支援するロボメカ技術のメガインテグレーション)

1P2-S-083 高分子電解質膜アクチュエータ(ICPF)の位置決め制御への応用 : 第2報:Au-NF115ICPFの位置決め制御特性と,残留変位の方向に及ぼす稼動イオンの影響(アクチュエータの機構と制御3,生活を支援するロボメカ技術のメガインテグレーション)

Modelling of a tunable capacitor with piezoelectric actuation

A modelling study for a tuneable micro-capacitor actuated by piezoelectric film actuator is presented in this paper. Compared to similar sized electrostatically actuated capacitors, piezoelectrically actuated capacitors have the potential to provide a larger tuning range and provide a more linear relationship between actuation voltage and capacitor gap change. FE and analytical models have been established, including both piezoelectric actuation and the electrostatic force due to bias voltage across the capacitor. The predictions of the two models are in good agreement. The models are used to investigate the displacement of the movable plate and the tuning range of a capacitor.

Enhanced electrochemical strain in polypyrrole films

Electrochemomechanical characteristics of polypyrrole (PPy) films, electrodeposited from tetra-n-butylammonium trifluoromethane-sulfonate dissolved in methyl benzoate (PPyFMS), have been investigated using a simultaneous measurement of electrochemomechanical deformation (ECMD) with cyclic voltammetry (CV) by comparing with PPy films deposited from p-phenol sulfonate in aqueous media (PPyPPS). The ECMD magnitude of PPyFMS film was reached around 9% at 1st cycle and was decreased to be about 3.2% at 20th cycle with electrochemical cycling in 1 M NaPF6. While in 1 M NaCl solution, the ECMD magnitude was 1.9% at 20th cycle in CV measurement. In the case for the PPyPPS film, ECMD magnitude at 20th cycle was around 0.8% and 1.1% in 1 M NaPF6 and 1 M NaCl solutions, respectively. The results indicate that the combination of electrolytes employed in both the electrodeposition and the device actuation plays the very important role for achieving the enhancement of ECMD magnitudes. In the case of ECMD behaviors, it was found that the electrolyte used in the film actuation determines the ECMD characteristics.

The Correlation between Electrically Induced Stress and Mechanical Tensile Strength of Polypyrrole Actuators

Abstract Highly stretchable and powerful PPy film actuators, prepared electrochemically from a methyl benzoate solution of tetra-n-butylammonium tetrafluoroborate (TBABF4), showed a positive correlation between the electrochemical stress and the mechanical tensile strength. The more flexible CF3SO3−-doped PPy suits multi-wound or multi-folded actuators that can be used as artificial muscles.

Design and Fabrication Aspects of an S-Shaped Film Actuator Based DC to RF MEMS Switch

This paper reports on design and fabrication aspects of a new microelectromechanical series switch for switching dc and RF signals. The switch consists of a flexible S-shaped film with the switching contact, rolling between a top and a bottom electrode in electrostatic touch-mode actuation. This design allows a low actuation voltage independent of the contact distance in the off-state. With a large contact distance, large overlapping switching contact areas are possible by obtaining a high off-state isolation. The RF transmission line and the MEMS part of the switch are fabricated on separate wafers, allowing an implementation of the switch with different RF substrates. The final assembly is done on device level for the first prototypes, even though the design provides the possibility of an assembly by full wafer bonding, leading to a near-hermetic package integrated switch. The measured prototype actuation voltages are 12 V to open and 15.8 V to close the contacts, with a resistance of 275 m/spl Omega/ of each contact at an estimated contact force of 102 /spl mu/N. The measured RF isolation with a contact distance of 14.2 /spl mu/m is better than -45 dB up to 2 GHz and -30 dB at 15 GHz, at a large nominal switching contact area of 3500 /spl mu/m/sup 2/.

Fabrication and characterization of diamond AFM probe integrated with PZT thin film sensor and actuator

In order to develop a diamond probe with a piezoelectric sensor and actuator for atomic force microscope (AFM), we fabricated lead zirconate titanate (PZT) thin film on a diamond thin film substrate and examined its piezoelectric properties. The PZT thin film was sputtered at room temperature and then annealed to obtain a perovskite structure. After rapid thermal annealing at temperature ramp rate of more than 10 °C/s and at temperatures of more than 500 °C in a nitrogen (N 2) ambient, the PZT thin film fabricated on flat Si substrates showed high piezoelectric constant, d 31, of about −90 pC/N, as well as in an oxygen (O 2) ambient. On diamond thin film substrates, the value of piezoelectric constant was as low as about −20 pC/N due to rough surface of the diamond film. After a poling treatment, however, its piezoelectric constant improved to about −65 pC/N. For realization of a PZT sensor and actuator on a diamond cantilever, the PZT thin film was also successfully patterned by reactive ion etching (RIE) in sulfur hexafluoride (SF 6) plasma using a platinum (Pt) upper electrode layer as an etching mask without any damage on the diamond layer. Based on the fabrication and patterning of PZT thin film together with microfabrication techniques of diamond film formed by chemical vapor deposition (CVD), we demonstrate the diamond AFM probe of 150 μm in length, 50 μm in width, and 5 μm in thickness with a PZT sensor and actuator of 1 μm in thickness. The resolution of image sensing and actuation force were estimated to be about 0.4 nm at a resolution of charge measurement of 1×10 −15 C, and 17 μN at an applied voltage of 8 V, respectively.

水素吸蔵合金ＬａＮｉ５の薄膜アクチュエータのパラジウム表面処理による高応答性

In this study, the effect of the palladium surface treatment was investigated on the mechanical response of the LaNi5 thin film actuator deposited on polyimide substrates. Since controlling the hydrogen concentration in film by changing the pressure may reversibly drive this actuator, this film actuator can be expected as a sensor and/or a controller of hydrogen gas flux in various hydrogen-related devices. In the present experiments, it was shown that the initiating time for the actuation to be measured after hydrogen gas exposure was reduced from 100 s to 1 s by the palladium surface treatment. This significantly improved mechanical response was attributed to the switching of the reactions in the rate determining steps. The rate determining reaction after the palladium treatment was no longer the dissociation of hydrogen gas molecules on the sample surface, but the hydrogen permeation or diffusion in the film. Furthermore, it was found that the high responsiveness induced by the palladium treatment was also caused by the high permeability of hydrogen in palladium film at room temperature.

Improved Response Time of a Thin Film Hydrogen Storage Alloy Unimorph Structure after Platinum Surface Treatment

In this study, the effect of a platinum surface treatment on the mechanical response of a LaNi5 thin film actuator deposited on polyimide substrates was investigated. Since this actuator could be reversibly driven by hydrogen pressure control, it could function as a sensor and/or controller of the hydrogen gas flux in various hydrogen related devices. In the experiments, the incubation period of the actuation after hydrogen gas exposure was reduced from 100 to 10 s by the platinum surface treatment. This significantly modified mechanical response is attributed to a switching of the reaction rate determining steps. The platinum treatment enhanced the decomposition rate of hydrogen gas molecules at the surface. The platinum treatment should bring about a change of rate determining step to a permeation/diffusion of the hydrogen atoms into the film.

Enhancement in electrochemical strain of a polypyrrole–metal composite film actuator

A polypyrrole (PPy)–zigzag metal wire composite film actuator, prepared electrochemically from a methyl benzoate solution of tetrabutylammonium trifluoromethanesulfonate (TBACF3SO3), showed up to 21.4% electrochemical strain, much larger than that (12.8%) of the corresponding PPy–CF3SO3−, driven in aqueous NaPF6 solution.

水素吸蔵合金薄膜ユニモルフ構造の白金表面処理による応答性の改善

In this study, the effect of the platinum surface treatment on mechanical response of LaNi5 thin film actuator deposited on polyimide substrates was investigated. Since this actuator could be reversibly driven by hydrogen pressure control, this actuator is expected as a sensor and/or controller of hydrogen gas flux in various hydrogen related devices.In the experiments, initiating time of the actuation after hydrogen gas exposure is reduced from 100 to 10 s by platinum surface treatment. This significantly modified mechanical response is attributed to switching of the reaction rate determining steps. Dissociation of hydrogen gas molecules on the sample surface is considered to be changed to permeation/diffusion of hydrogen atoms in the film by the platinum treatment.

円形噴流の制御に関する研究 : PVDFフィルムアクチュエータによる軸方向励起(S22-1 噴流の制御-1,S22 流れ制御の技術)

Turbulent mixing of a circular jet, which is commonly used in many gas turbine applications, has been studied from the viewpoint of control. The static pressure fluctuation is a basic flow parameter in turbulence. In this study, the vortex structure of the free shear layer in the circular jet is excited by the piezo film actuators. The effect of axial excitation on the turbulent mixing is clarified by simultaneous measurement using hot wire anemometer and static pressure probe.

パンタグラフ機構のスマート構造化による振動制御(スマートストラクチャ,OS.6 折り紙・針金/スマートストラクチャ)

H_2 controller is designed with the reduced order model of smart pantograph structure which is obtained by finite element and modal analyses. The control force is applied by the piezoelectric film actuator and the feedback signals are detected by the accelerometer in the system. The vibration response is suppressed by modal control. The placement of the piezoelectric actuator and the H_2 control system are simultaneously optimized by using GA to achieve an enhanced vibration control performance. It has been verified by simulations that the enhanced performance for the vibration suppression can be achieved by the present method.

Low-Voltage High-Isolation DC-to-RF MEMS Switch Based on an S-shaped Film Actuator

This paper presents a new electrostatically actuated microelectromechanical series switch for switching dc to radio frequency (RF) signals. The device is based on a flexible S-shaped film moving between a top and a bottom electrode in touch-mode actuation. This concept, in contrast to most other microelectrochemical systems (MEMS) switches, allows a design with a low actuation voltage independent of the off-state gap height. This makes larger nominal switching contact areas for lower insertion loss possible, by obtaining high isolation in the off-state. The actuation voltages of the first prototype switches are 12 V to open, and 15.8 V to close the metal contact. The RF isolation with a gap distance of 14.2 /spl mu/m is better than -45 dB up to 2 GHz and -30 dB at 15 GHz despite a large nominal switching contact area of 3500 /spl mu/m/sup 2/.

進行波を用いた薄膜バルブレスマイクロポンプの開発(J22-3 センサ・アクチュエータシステムとその知能化(3),J22 センサ・アクチュエータシステムとその知能化-実環境で活躍するメカトロニクスを目指して)

Micropumps play a significant role in fluid transportation system of μ-TAS. We propose a peristaltic micropump system composed of a microchannel made of silicon rubber. Bottom surface of the microchannel is deformed by the electrostatic attraction between upper and lower electrodes made of copper thin films. Since the pump has simple structure using the electrostatic thin film actuators without valves, the fabrication process is also as simple as just stacking organic films or layer on PMMA substrate. The micropump is suitable for low-cost disposable applications. We could observe clear deflection of the channel wall which is proportional to the a square of the applied voltage. In addition, we confirmed active motion of microbeads in the fluid by the peristaltic actuation of electrostatic force.

402 マイクロアクチュエータ用PZT圧電薄膜創製技術の開発(GS-16 精密計測・精密加工)

402 マイクロアクチュエータ用PZT圧電薄膜創製技術の開発(GS-16 精密計測・精密加工)