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AbstractWe present a confocal fluorescent endomicroscopic system with a Lissajous scan using an asymmetric polymer tube and piezoelectric (PZT) tube actuator. The fiber cantilever’s scanning part is often inside the PZT tube actuator to reduce the scanner’s rigid length and enhance the beam deflection via a lever mechanism. Here, the mathematical model of the PZT tube actuator-based lever mechanism is first proposed by considering the piezoelectric parameters of the actuator and Euler-Bernoulli beam deflection, showing a good agreement with experimental data. In addition, an elliptical polymer tube is used to divide the resonant frequencies of the fiber cantilever, allowing enough scanning amplitudes and alleviating the inherent cross-coupling issue of a PZT tube actuator. The design optimization is performed by selecting the optimal lever length and the shape of the PFA tube. The implemented endomicroscopic probe could successfully acquire imaging results from both a lens-cleaning tissue and an ex-vivo mouse colon.

A devised tip-tilt guide mechanism (TTGM) for the fast steering of a large-scale mirror is presented. The TTGM uses a parallel structure with four struts, in which a double right-circular notch and a leaf spring are serially connected via a nondeformable rectangular linkage in aid of an axial flexure at the center of the payload. The benefits provided by the TTGM include pure rotation in the desired directions, an adaptable mechanism for a large and heavy mirror, and an adjustable virtual pivot of the moving body allowed by the configuration design. Closed-form stiffness equations of the individual flexure hinges are derived, and the equations of motion of the TTGM are mathematically formulated to predict the behaviors of the mechanism. To validate the performance of the TTGM, a design is presented and optimization of the geometric parameters of the TTGM is carried out. The model prediction accuracy for the resonant frequency relative to experimental results is found to be satisfactory, with errors of less than 11.4%. It is proven that the devised TTGM is an appropriate structure as a two-axis guide mechanism in three-dimensional space for the 160-mm diameter mirror with an angular travel range of 1 mrad. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new in-plane XYθz nano-positioning stage that utilizes piezoelectric actuators and flexure mechanisms. The proposed stage has an aperture and is compact, which facilitates its application in measurement equipment, especially those used for biological specimens. The stage has four piezoelectric actuators and four bridge-type flexure mechanisms, which are used to amplify the small motions produced by the piezoelectric actuators. This paper describes the modeling and design optimization of the stage, which has X- and Y-direction motion ranges of 300 μm and a θz-direction motion range of ±3.9 mrad. The stage measures 150 × 150 × 23 mm, and its aperture is 50 × 50 mm. [ABSTRACT FROM AUTHOR]

To establish of standard technique of nanolength measurement in a two-dimensional plane, a new (AFM) system has been designed. In this system, measurement uncertainty is dominantly affected by the Abbe error of the XYZ scanning stage. No linear stage is perfectly straight; in other words, every scanning stage is subject to tilting, pitch, and yaw motion. In this article, an AFM system with minimum offset of XYZ sensing is designed. And, the XYZ scanning stage is designed to minimize the rotation angle because Abbe errors occur through the multiply of offset and rotation angle. For XY stage, optimal design is performed to minimize the rotation angle by maximizing the stiffness ratio of motion direction to the parasitic motion direction of each stage. For the Z stage, the optimal design of maximizing the first-resonant frequency is performed. When the resonant frequency increases, the scan speed is improved, thereby reducing errors caused by sensor drift. This article describes the procedures of selecting parameters for the optimal design. The full range of the XYZ scanner is 100 μm×100 μm×10 μm. Based on the solution of the optimization problem, the XYZ scanner is fabricated. And tilting, pitch, and yaw motion are measured by autocollimator to evaluate the performance of XY stage. [ABSTRACT FROM AUTHOR]

This paper presents a novel six-degree-of-freedom magnetic levitation fine stage for a dual-servo stage. The proposed fine stage is levitated and actuated, using a voice coil motor actuator with a Halbach magnet array. For a dual-servo stage, fine stage performance is deeply intertwined with coarse stage performance. Because the fine stage is installed over the coarse stage, the overall size of the fine stage can be limited by the moving plate of the coarse stage. Therefore, magnetic flux modeling and optimization are performed to manufacture optimal fine stages. To control the fine stage, actuator kinetics and sensor kinematics are proposed. Homing control is implemented by using linear variable differential transformers, whereas fine control is implemented by capacitance sensors and laser interferometers. Finally, experimental results of in-position stability, moving range, and repeatability are presented. [ABSTRACT FROM AUTHOR]

There exist microscopes that are able to obtain the chemical properties of a sample, because there are some cases in which it is difficult to find out causality of a phenomenon by using only the structural information of a sample. Obtaining the chemical properties of a sample is important in biomedical imaging, because most biological phenomena include changes in the chemical properties of the sample. Hyperspectral imaging (HSI) is one of the popular imaging methods for characterizing materials and biological samples by measuring the reflectance or emission spectrum of the sample. Because all materials have a unique reflectance spectrum, it is possible to analyze material properties and detect changes in the chemical properties of a sample by measuring the spectral changes with respect to the original spectrum. Because of its ability to measure the spectrum of a sample, HSI is widely used in materials identification applications such as aerial reconnaissance and is the subject of various studies in microscopy. Although there are many advantages to using the method, conventional HSI has some limitations because of its complex configuration and slow speed. In this research we propose a new type of multimodal confocal hyperspectral imaging microscopy with fast image acquisition and a simple configuration that is capable of both confocal and HSI microscopies. [ABSTRACT FROM AUTHOR]

Many researchers have studied the actuation of piezoelectric actuators using a model of the hysteresis of piezoelectric transducer (PZT). However, these hysteresis modeling methods to remove the nonlinearity in PZT did not include the consideration of PZT's creep effect which is a very important factor in many open-loop application of piezoelectric actuator. In order to compensate for the creep effect of PZT as well as the hysteresis of displacement, the notion of "voltage creep" is proposed in this article. And, with the notion, a new actuation method of piezoelectric actuators for removing the hysteresis and creep will be proposed and the actuation result will be presented. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]