New light-driven actuators based on films of polymer polyvinylidene fluoride are described. The actuators employ the photomechanical bending of the polymer film caused by low power (10 mW and less) laser radiation. The photomechanical effect combines various physical mechanisms, such as anisotropic thermal expansion, converse piezoelectric mechanism along with photovoltaic and pyrolelectric ones, while the mechanism of thermal expansion is dominant for slow motion. The static force applied by the actuators to external objects was measured with a torsion balance. It is proportional to the power of laser beam and could be as high as 10^-4 N for a 50- micron film illuminated with a 10-mW laser beam. Mechanical vibrations of the strips of the photomechanical polymer were observed when the periodic laser pulses were used. The resonance frequency is inversely proportional to the square of the length of the strip. Resonance frequency measurements were used to determine the modulus of elasticity of the films, which was close to 3.0x10⁹ Pa. Two possible applications are discussed: photonic switch and adaptive mirror. The proposed actuators have a potential of being used as the components of future light-driven micro/nano systems.

The presented research relates to the dynamic studies of the so-called optomechanical effect in chalcogenide glasses. We present a novel study of a dynamic response of the atomic force microcantilever balance and chalcogenide glass upon illumination with alternating polarized light up to the resonant frequency of the cantilever. The sharp response peak of the microcantilever system was found at frequencies around ~22.7 kHz, however, the origin of the effect remains speculative. Nevertheless, it has been demonstrated that the cantilever-chalcogenide glass reliably responses to the polarized light change up to a frequency of ~5 kHz (200 μsec) or possibly faster.

There are several new tools for manipulating microscopic objects. Among them, optical tweezers (OT) has two distinguishing advantages. Firstly, OT can easily release an object without the need of a complicated detaching scheme. Secondly, it is anticipated to manipulate an object with six degrees of freedom. OT is realized by tightly focusing a laser beam on microscopic objects. Grabbing and releasing is easily done by turning a laser beam on and off. For doing a dexterous manipulation on an object, a complicated potential trap must be calculated and applied. We foresee that such calculation method will be developed in the near future. One of the candidates for implementing the calculated trap is scanning optical tweezers (SOT). SOT can be built by using actuators with a scanning frequency in the order of a hundred Hertz. We need fast scanners to stably trap an object. In this study, we present our design of such SOT. The SOT uses piezo-actuated tilt mirror and objective positioner to scan full three-dimensional workspace.

We performed a spectroscopy-tomography study of a single living cell to obtain 3-dimensional distribution of proteins in high spatial resolution in real time. In this report, we mention the 6-DOF manipulation of a single living cell to achieve the high spatial resolution 3-dimentional spectrometry. We propose the proximal two- beam optical tweezers as rotational operation. We decided to illuminate the proximal two points in each from different directions using two beams. In this case, the light pressure generated by light absorption is made to act as rotating torque. Using this proposed method, we can operate the rotational velocity of a microsphere regardless of refractive index distribution by non-contact operation. In addition, rotational speed is controlled by optical PWM operation. This proposed optical PWM operation is that the received light intensity is changed by the illumination time. This method can be developed into the 6-DOF control of single-cell. And we propose the optical spatial filtering method, paying attention to the diffracted light that is generated from a sample, as translational velocity measurement. This measurement derives the arbitrary component of the spatial frequency from the random refracted index distribution as the periodic light intensity distribution. This periodic light intensity distribution changes in accordance with the translation of an object. Therefore, we can obtain the translational velocity of the non- labeled cell by high-response photodiode.

A varifocus lens by liquid pressure has been developed to change the focal length from a concave to a convex shape by adjusting the liquid pressure. It consists of a polymer film, an acrylic plate, and liquid and it is filled up with the liquid in its cavity. The deformation of the refraction surface of the lens is analyzed theoretically. An experiment by He-Ne laser is performed with a plano-convex type lens. The dynamic range of the focal length of the convex lens is from 50 mm to 250mm. The application for a YAG laser with 1.06μm of wavelength is demonstrated experimentally. The focus was adjusted along the material surface without moving the optical element. As a result, the control of the beam spot diameter is succeeded. Finally, the laser processing is demonstrated to manufacture Fe compressed powder sheets. Its melting marks along a focus change are formed with a minimum width of 100μm.

White-light interferometry combined with phase-shift technology becomes a widely used 3-D shape measurement tool in precision engineering. In white-light interference 2π phase ambiguity can be avoided in measurement of optical path difference by searching a modulation peak of light intensity change. This interference surely involves a change in modulation intensity against optical path difference, which is an envelope curve of sinusoidal variations. Then, the phase-shift algorithm by which phase is accurately measured even under the modulation change is required. There is often another requirement that phase shift between captured interferograms would be not restricted to π/2 in the use of the algorithm. Computer simulation has been carried out to estimate phase errors which are retained by applying well-known algorithms to a white-light interference. They are Carre, 4-frame, 5-frame Hariharan, and 7-frame Groot algorithms. All the algorithms have non-negligible errors under the both requirements. Therefore, I extract individual terms (I_i±I_j) in an algorithm equation by considering symmetry of light intensity against phase, where I_j is light intensity just after the j-th shift. Using computer simulation again, I then search for appropriate coefficients by which the terms are multiplied in the equation. I finally have found an algorithm satisfying both the requirements.

A polarization measurement is proposed to detect a birefringence and an optical rotation distribution in a microscopic area. A residual stress caused by industrial processes and molecular orientation are observed by visualizing birefringence distribution. It is possible to analyze components of material with optical rotation. This measurement system consists of a He-Ne laser, polarizers, a half-wave and a quarter-wave plate. By changing combination of rotating angle of half-wave plate, quarter-wave plate and analyzer, we can obtain retardation, azimuthal angle of birefringence and optical rotation angle independently. An analytical algorithm with local-sampling phase shifting is employed for achieving a high resolution. The errors caused by the initial polarized characteristic of the optical system are corrected by subtracting the in-phase vector.

Using the real-time holographic interferometry, we have studied the way of variation of thermal expansion coefficient as a function of temperature. For this purpose we have used a particular set-up appropriate to in-situs developing process. In the reconstruction step, the observer will see-through the hologram ,a virtual image which is coincident with the wave diffracted by the object itself, and an interference pattern will appear. If then the temperature of the object is increased, this will cause the movement of fringe. Hype number of displaced fringes give measure to evaluatethe coefficient of the thermal expansion of the object. The corresponding curves is depicted.

We propose a strategy for a micromanipulation method using surface stabilized ferroelectric liquid crystals (SSFLC). By adjusting the frequency of the applied ac electric field, the surface layers that cannot follow an applied ac electric field are constructed in SSFLC. In addition, by applying a sawtooth wave voltage, net flow along the smectic layer is generated. The flow direction is reversed by changing the polarity of the sawtooth wave. Consequently, the particles dispersed in SSFLC can be driven bidirectionally along the smectic layer. The particle velocity depends on the temperature, amplitude and frequency of the applied voltage.

Three-dimensional light structures can be created by modulating the spatial phase and polarization properties of the laser light. A particularly promising technique is the Generalized Phase Contrast (GPC) method invented and patented at Riso National Laboratory. Based on the combination of programmable spatial light modulator devices and an advanced graphical user-interface the GPC method enables real-time, interactive and arbitrary control over the dynamics and geometry of synthesized light patterns. Recent experiments have shown that GPC-driven micro-manipulation provides a unique technology platform for fully user-guided assembly of a plurality of particles in a plane, control of particle stacking along the beam axis, manipulation of multiple hollow beads, and the organization of living cells into three-dimensional colloidal structures. These demonstrations illustrate that GPC-driven micro-manipulation can be utilized not only for the improved synthesis of functional microstructures but also for non-contact and parallel actuation crucial for sophisticated opto- and micro-fluidic based lab-on-a-chip systems.

A design of a microscopy system tailored for optical tweezers with a capability of an automatic focusing is presented. In this design, we utilize lenses, motorized mechanical stage, lamp and a digital camera to magnify and see a micrometer sized spheres floating in a thin film of water. The system can automatically translate the stage that holds the specimen to obtain the best focused image. The best focused image is "sharp." Mathematically, the best focused image shows the maximum amount of high frequency terms from the images obtained by translating the stage. The metric that calculates how one image is focused is called the Focus Measure (FM). Unfortunately, low frequency components also increase this FM. And an optical imaging system is a low pass filtering system. Thus the primary concern is to lower the low frequency components in an image. The electric signals from each pixel of a CCD include noises that are inherent in each pixel. The result of this is an FM profile that has multiple local maxima. This is the most critical reason why an Automatic Focusing System (AFS) yields incorrect focusing results. Available techniques have been tested and from this experience, the most appropriate Focus Measure Filter (FMF) that has the sharpest FM despite the low frequency terms and noises has been selected. Furthermore, a maximum search algorithm that is immune to local maxima in an FM profile is discussed. Using this FMF and search algorithm, an Automatic focusing system (AFS) tailored for optical tweezers is presented. The system is implemented on personal computers equipped with Pentium 4 processors.

We report on an experimental comparison between PMN-PT single crystal resonators with commercially available QCM resonators showing significant superiority for new sensors over conventional quartz. Thickness acoustic mode resonators made out of PMN-PT film were fabricated for these tests. The thickness mode resonators make use of a mechanically polished PMN-PT single crystal film of thickness 30μm. The sensor response to methanol vapor condensation shows a frequency shift for the PMN-PT resonator 1000 times larger under the same environmental conditions than the commercial quartz microbalance sensor. A surface acoustic mode resonator using mechanically polished PMN-PT single crystal film of thickness 100μm was also fabricated and tested. The dimensions of the PZN-PT film sample were 5×2×0.12mm³. Thin gold interdigitated electrodes were applied on one side of the sample. A 50nm-thick gold film was evaporated on the surface and patterned using standard photolithography. This resonator sample also exhibits a resonance frequency similar to that of a commercial quartz microbalance sensor. A large frequency drop or sensitivity is again found for the PMN-PT sensors than the quartz sensors in this case. The frequency shift in the PMN-PT surface mode resonator is ~300 times larger to methanol vapor loading than in the quartz resonator.

The fluidic muscle cylinder consists of an air bellows tube, flanges and lock nuts. Its features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. Recently, unlikely the pneumatic cylinder, the fluidic muscle cylinder without air leakage, stick slip, friction, and seal was developed as a new concept actuator. It has the characteristics such as light weight, low price, high response, durable design, long life, high power, high contraction, which is innovative product fulfilling RT(Robot Technology) which is one of the nation-leading next generation strategy technologies 6T as well as cleanness technology. The application fields of the fluidic muscle cylinder are so various like fatigue tester, brake, accelerator, high technology testing device such as driving simulator, precise position, velocity, intelligent servo actuator under special environment such as load controlling system, and intelligent robot. In this study, we carried out the finite element modeling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was fabricated and tested. Finally, we compared the results between the test and the finite element analysis.

Advances in low power design open the possibility to harvest energy from the environment to power electronic circuits. Electrical energy can be harvested from various transducers including piezoelectric materials. Piezoelectric materials can be used as mechanisms to transfer mechanical energy usually ambient vibration into electrical energy that can be stored and used to power other devices. It has been found that a piezoelectric device attached to a beam with cantilever boundary conditions provides an effective configuration for capturing transverse vibrations and converting them into useful electrical power. Piezoelectric thin films attached to a silicon beam also have attracted attention for energy harvesting applications. In this paper, we present the results of a preliminary study of the effect of vibration amplitude on the performance of a PMN-PT single crystal beam with interdigitated electrodes pattern. The structure is used to demonstrate that feasibility of a novel piezoelectric monomorph cantilever beam for producing high AC voltage. The energy harvesting capability of a PMN-PT cantilever beam is tested on a 10mm-long and 1.2mm-wide rectangular prototype made out of 0.1mm-thick PMN-PT film with interdigitated electrodes. The experiments are performed to test the level of AC voltage and current generated from the PMN-PT cantilever beam device when subjected to transverse vibration of varying amplitude at the first mode of the resonant frequency. The frequency response of the monomorph prototype shows that the first mode resonance frequency of the excitation model is approximately 190Hz. We found that increasing the poling voltage also causes increased output AC voltage magnitude. These tests show that a significantly high AC voltage of 13V was achieved with 50μm shaker displacement. The measured RMS current was ~20μA.

Wearable robots, especially power suits to enhance human activity are one of the most interesting and important topics. This study aims t o develop a wearable robot that is small-size, light-weight for improving human perfor- mance and reducting muscle fatigue. So we proposed smart suit with variable stiffness mechanism that utilize elastic forces for assist and make assistance control by impedance control. Because of to utilize elastic forces for assist, the capacity of the suit do not reliance on weight of actuators and their's energy source well than conventional power suits. In consequence, we think the suit can realize miniaturization and getting light-weight. In a previous study, we verified the effectiveness of smart suit with variable stiffness mechanism by experiments and simulations in order to design the suit which can tune the stiffness of joint mechanically, and had been able to confirm the effectiveness. Based on these results, we design the smart suit with variable stiffness mechanism that be able to control number of working spring by small actuator, and at any knee joint angle, elastic energy occurrence is variable by displacement angle of ankle joint. We could obtain a result of the output per a mass of the suit is more large than conventional power suits. And we confirm that reducting muscle fatigue by experiments on knee bends and walking in case that subjects wear the suit. In this paper, we show the suit that we developed and effectiveness of the suit for human working.

Bare-chip packaging becomes more popular along with the miniaturization of IT components. In this paper, we have studied flip-chip process, and developed automated bonding system. Among the several bonding method, NCP bonding is chosen and batch-type equipment is manufactured. The dual optics and vision system aligns the chip with the substrate. The bonding head equipped with temperature and force controllers bonds the chip. The system can be easily modified for other bonding methods such as ACF. In bonding process, the bonding force and temperature are known as the most dominant bonding parameters. A parametric study is performed for these two parameters. For the test sample, we used standard flip-chip test kit which consists of FR4 boards and dummy flip-chips. The bonding temperatures are chosen between 25°C to 300°C. The bonding forces are chosen between 5N and 300N. To test the bonding strength, a bonding strength tester was designed and constructed. After the bonding strength test, the samples are examined by microscope to determine the failure mode. The relations between the bonding strength and the bonding parameters are analyzed and compared with bonding models. Finally, the most suitable bonding condition is suggested in terms of temperature and force.

In this letter, we proposed a simple and cost-effective variable optical attenuator (VOA) through controlling a mechanical misalignment between 2 single mode fibers. A piezoelectric ceramic tube having 4 electrodes on the surface is the key component in our proposed structure. We can change the deflection of the tube by controlling the applied voltage on the electrodes of the tube, which causes the optical loss to be dependent on the applied voltage. The fact that the piezoelectric ceramic tube can be easily fabricated by using the electro-phoretic deposition processing makes our structure more attractive for mass production. The tube-fabrication processing is out of the range in this paper. So, the detail technical approach of the tube fabrication is excluded intentionally. The numerical analysis about the optical loss related to the various mechanical offsets is also investigated. From our experimental results, the dynamic range of the proposed structure is about from 0 to 25 dB when the applied voltage range is from 0 to 600 V DC. Our proposed structure can be a good candidate for a simple and cost-effective variable optical attenuator in optical communication system field.

This study focuses on the design and analysis of a Rotor type magneto-rheological fluid (MR Fluid) brake and clutch. The brake's braking torque and the clutch's torque output can be easily controlled by adjusting the MR fluid and the configuration of Rotor. Electromagnetic finite element analysis(FEA) is performed, using FEMLAB software of the COMSOL Group, to find out the optimization conditions for the design of the Rotor type MR Fluid clutch and brake. In this paper, the design method of the Rotor type MR Fluid brake and clutch is investigated theoretically. The equation of the torque transmitted by the MR fluid within the Rotor type brake and clutch is derived to provide the theoretical foundation in the rotor design of the brake and clutch. The output torque values are recorded for different input velocities and applied magnetic fields, and the experimental results are compared with the theoretical results. Theoretical and experimental analyses have illustrated that this Rotor type MR fluid brake and clutch can transfer high controllable torques with a very fast time response. It was demonstrated that the Rotor type MR fluid clutch and brake have a strong capability of transmitting and isolating the high torque.

Auto focus actuator, which is used to move a lens module in the mobile phone having a camera module, is developed. Camera module containing auto-focus actuator requires to minimize total size because of application area such as mobile phone, digital camera, and personal digital assistant. There are stepping motor, voice coil motor, and piezoelectric motor as auto-focus actuator. In this paper, voice coil motor having new electromagnetic configuration is proposed. And actuator using proposed voice coil motor is developed by magnetic field analysis using finite element method and magnetic circuit analysis. The size of the developed actuator is reduced to 67.3% compared with actuator using previous electromagnetic configuration. From the performance test, the developed actuator has moving stroke of 0.4mm, hysteresis of 20μm, full stroke current of 100mA, and unit step motion of 10μm.

Piezoelectric actuators are used as critical units or elements of various electromechanical systems. In this paper, we propose a novel piezoelectric actuator cantilever with double interdigitated electrode patterns. We investigate the possibility of both flexural and longitudinal actuation capabilities of the double interdigitated electrode patterns applied on a piezoelectric cantilever structure. This monomorph structure has the interdigitated electrode patterns top and bottom. The structure also uses single-crystal relaxor ferroelectric material. We separately pattern interdigitated electrodes on the top and bottom surfaces of a PMN-PT single crystal cantilever beam. The interdigitated electrode design on a surface of the cantilever beam results in an electric field gradient. This results in a flapping actuation. Previously, we showed that the vertical field component induced by the interdigitated electrode is dominant over the horizontal component under input bias voltage, and generates subsequent contraction of the surface along the axial direction after poling. In this paper, we show that a contraction on the top surface and an elongation on the bottom leads to upward bending motion because of the differential contraction along the thickness induced by the interdigitated electrode pattern. Similarly, an equivalent elongation on the top and bottom surfaces is shown to lead to longitudinal motion in the double interdigitated electrode sample.

In this paper, we present a polymer actuator which is made of dielectrics elastomer. Recently, most polymer actuators utilize expansive force and some layers (>10 layers). They have the disadvantage of pre-strain. As time passes, the performance of the actuator deteriorates. We manufacture polymer actuators with numerous layers (>100 layers) in order to make up the defect in the current. A numerous layer actuator is a structure which can take constant strain without pre-strain operating and a driven method using only contract force. In this paper, its basic concepts are briefly introduced and issues about design and fabrication are discussed. Finally, results of the experiments are given and their effectiveness confirmed

Near field recording (NFR) has been introduced as a new optical data storage method to realize higher data density beyond the diffraction limit. As the data density increases, the track pitch is remarkably reduced to about 400nm. Thus, more precise actuator is required and we propose a dual servo actuator to improve the accuracy of actuator. The proposed dual servo actuator consists of a coarse actuator and a fine actuator, multisegmented magnet array (MSMA) voice coil motor (VCM) and PMN-PT actuator. In design of VCM actuator, a novel magnetic circuit of VCM with MSMA is proposed. It can generate higher air gap flux density than the magnetic circuit of VCM with the conventional magnet array. In design of fine actuator, the fine actuator including PMN-PT single crystal instead of the conventional PZT is proposed. The displacement gain of PMN-PT fine actuator is 26 nm/V and that of PZT fine actuator is 17 nm/V. The displacement gain is increased by 53 %. To evaluate tracking performance of the manufactured dual servo actuator and to assign the proper role to each actuator, the PQ method is selected. From experiment results, the total bandwidth of the dual servo actuator is increased to 2.5kHz and the resolution is 25 nm. Comparing with the resolution of one servo actuator, 70 nm, we can find that the accuracy of actuator is remarkably improved. And the proposed dual servo actuator shows satisfactory performances to be applied to NFR and it can be applied to other future disk drives.

In this paper, the design of a partially-rotating piezoelectric motor/actuator based on a cylindrical piezoelectric material is presented. A prototype of the motor is developed and its performance, with respect to yielding a controllable partial rotation, is evaluated. The details of the design, development and tests will be duly provided in the paper.

Among the electric motor drives, the piezoelectric actuator (PA) is one drive which is becoming very popular in high precision biomedical applications, such as intracytoplasmic sperm injection. The main benefits of a PA include low thermal losses and, most importantly, the high precision and accuracy achievable consequent of the driect drive principle. One major source of uncertainties in PA control design is the hysteresis behavior which yields a rate-independent lag and residual displacement near zero input, reducing the precision of the actuators. Due to the typical precision positioning requirements and low offset tolerance of PA applications, the design and control of these systems, under the influence of these uncertainties, is particularly challenging since conventional PID control usually does not suffice in these application domains to meet the stringent performance requirements. In this paper, we consider the design and realization of a piezo stack actuator which is capable of linear motion and non-full rotation to fulfill the stringent requirements associated with sperm injection applications. A complementary precise control system is developed employing a robust adaptive control algorithm to reject the hysteresis phenomenon associated with general PAs and to achieve rapid and highly precise positioning. The controller comprises of a PID feedback component and an adaptive component for hysteresis compensation. The adaptive component is continuously refined based on just prevailing input and output signals. In the paper, it will be proven that the tracking error can asymptotically converge to zero. In addition, analytical quantification is given to illustrate the improvement of the system's transient performance. Real-time experimental results verify the effectiveness of the proposed micro actuator for high precision motion trajectory tracking in intracytoplasmic sperm injection using mice eggs.