Browsing by Author "Liu, Tzong-Shi"

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Force Sensor Design and Measurement for Endodontic Therapy
(2013-07-01)
Tsao, Chih-Chiang
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Lin, Fang-Yu
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Liou, Ji-Wei
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Wen, Ping-Han
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Peng, Chieh-Chung
To assist endodontic therapy, in this paper, a force sensor is designed and fabricated for measuring the axial force and the bending moment simultaneously. By detecting the bending moment, we can know the severity of bending. Axial force detection is also desired, as excessive axial forces may result in instrument buckling or even root canal perforation. This paper installs three sensing cells in each of two planes to detect the bending direction. Each sensing cell consists of a pressure-sensitive electric conductive rubber and an electrode. The size of the force sensor is 1.4-mm wide and 6-mm high for matching the size of endodontic instruments and making it feasible in the endodontic treatment. Experimental results on accuracy, repeatability, and nonlinearity are presented to validate the proposed sensor.
Grating Pitch Measurement Beyond the Diffraction Limit with Modified Laser Diffractometry
(2011-06-01)
Pan, Shan-Peng
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Liu, Tzong-Shi
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Tasi, Min-Ching
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Liou, Huay-Chung
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機械工程學系
The demand for accurate measurements of nanostructures is increasing for the microprocesses and nanotechnology used in the semiconductor industry. In this study, we present an improved method for measuring gratings with a pitch size lower than one-half of the laser wavelength by using a modified laser diffractometer (LD). In experiments, the modified LD with a 633nm laser is used to measure a grating with a 288nm pitch size. This result is compared with results measured by both a metrological atomic force microscope and the traditional LD with a 543nm laser. The validity of this method is demonstrated. The difference between the pitch size of 288nm obtained by these three methods is approximately 0.17 nm. (C) 2011 The Japan Society of Applied Physics
Laser Diode Feedback Signal for Position Sensing Using Self-Mixing Interference
(2009-03-01)
Tsai, Meng-Yen
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Liu, Tzong-Shi
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Schlesinger, Tuviah E.
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機械工程學系
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Department of Mechanical Engineering
We modified a digital versatile disk (DVD) pickup head as a DVD actuator with a laser diode package for sensing. Tuning a tilting coil in the DVD actuator causes the tilt of a laser diode to compensate misalignment between a target surface and the laser diode facet. Experimental results show that tuning the tilting coil compensates misalignment between both surfaces to achieve effective self-mixing signal. Furthermore, we present the conformity between the output voltage and the target surface displacement from a laser diode package using the self-mixing effect. The resolution in linear region of self-mixing signal is 100 mV/nm. (C) 2009 The Japan Society of Applied Physics.
Liquid refractometer based on immersion diffractometry
(2007-07-23)
Lu, Sheng-Hua
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Pan, Shan-Peng
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Liu, Tzong-Shi
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Kao, Ching-Fen
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機械工程學系
This study presents a laser diffractometric refractometer for measuring the refractive index of liquids. The refractive index is determined by rotating a reflection grating that is immersed in the fluid under test, and measuring the first- order Littrow diffraction angle. The Littrow angle is easily detected form the interferogram formed by the diffracted beam from the grating and the reflected beam from the liquid surface. No special cell for liquids is required. The alignment and measuring processes are simpler than those of other refractometers. The results of a feasibility experiment reveal that the accuracy of the proposed approach is about 0.003 for a refractive index of around 1.3. (c) 2007 Optical Society of America.
Method for Determining the Angle in Two Dimension Nanoscale: Pitch Grating
(2011-06-01)
Pan, Shan-Peng
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Liu, Tzong-Shi
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Tasi, Min-Ching
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Liou, Huay-Chung
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機械工程學系
A two-dimensional (2D) grating is useful for calibrating the accuracy of an electron microscope and atomic force microscope (AFM). An inter laboratory comparison has been carried out for measuring pitches and angles of 2D gratings with 292 and 1000nm pitches using both AFM and an optical diffractometer (OD). The grating angle at the 292nm pitch size was obtained at some of the laboratories by the conventional OD method. However, they could not measure the grating angle when the grating pitch was smaller than (lambda/2) x root 2, where lambda denotes the laser wavelength. We propose a diffraction angle rotation method of grating angle measurements. Using a precision rotary table along with diffractive light, we accurately measure a 2D grating angle for any pitch size larger than lambda/2. (C) 2011 The Japan Society of Applied Physics
Modifications of Control Loop to Improve the Depth Response of Autonomous Underwater Vehicles
(2014)
Hsu, Sheng-Ping
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Liu, Tzong-Shi
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機械工程學系
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Department of Mechanical Engineering
During a constant depth maneuver of an autonomous underwater vehicle (AUV), its pitch attitude and stern plane deflections create forces and moments to achieve equilibrium in the vertical plane. If an AUV has a proportional controller only in its depth control loop, then different weights or centers of gravity will cause different steady-state depth errors at trimmed conditions. In general, a steady-state depth error can be eliminated by adding an integral controller in the depth control loop. However, an improper integrator may lead to a bad transient response, even though the steady-state depth error can finally be eliminated. To remove the steady-state depth error, this study proposes methods that adjust the depth command and add a switching integral controller in the depth control loop. Simulation results demonstrate that the steady-state depth error can be eliminated and the transient response can be improved.
Nanoparticle Manipulation Using Atomic Force Microscopy
(2010-02-01)
Tsai, Meng-Yen
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Liu, Tzong-Shi
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機械工程學系
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Department of Mechanical Engineering
To develop nanotechnology, nanoparticle manipulation plays all Important role in the assembly of nanoelements This Study aims to Manipulate nanoparticles using an atomic force microscope and X-Y positioning stage Strain gauges serve as sensors to Measure the travel distance of piezo-drivers in an X-Y stage In all atomic force microscopy system Nanoparticles are pushed based oil sliding mode control whose robust properties can deal with model uncertainty and disturbance In addition, a fuzzy controller is responsible for compensating "up-particle contact loss". so its to establish all accurate and stable manipulation system Experimental results demonstrate pushing nanoparticles oil Inclined substrates, different limited scanning ranges with different slope angles, and removing and remaining nanoparticles oil inclined substrates.
Optical-Characteristic Measurement of Flexible Display for Reliability Test
(2009-01-01)
Wen, Bor-Jiunn
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Liu, Tzong-Shi
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Chen, Cheng-Hsien
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Ko, Hsin-Yi
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Chung, Zong-Ying
The purpose of this study is to put forward a new reliability-test method for measuring optical characteristics of flexible display under different radii of curvature by using a flexible-characteristic inspection system. In addition, for reliability test this study also researches about the optical measurement of flexible display after being bended several times. According to inspection results of the bending characteristics depicted on flexible display, a designer or maker of flexible display can design useful and comfortable flexible display product for human being to obtain more comfortable lifestyle in ubiquitous environment.
Precision Measurement of Sub-50 nm Linewidth by Stitching Double-Tilt Images
(2010)
Pan, Shan-Peng
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Liou, Huay-Chung
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Chen, Chao-Chang A.
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Chen, Jr-Rung
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Liu, Tzong-Shi
In this paper we present a stitching double-tilt image method (SDTIM) to measure sub-50 nm linewidth and to evaluate the measurement uncertainty. The SDTIM employs a parallel image method using a tilt mechanism to obtain two side scans. Moreover, the stitching method is used for linewidth determination. Experiments were performed by atomic force microscopy (AFM) using an ultrasharp tip, whose radius is smaller than 5 nm. The sample rotation axis is set parallel to the top surface of the sample in order to reduce the problem of measurement position variation. Experimental results show that the developed SDTIM can be used with an uncertainty of less than 5 nm at a confidence level of 95%. (C) 2010 The Japan Society of Applied Physics
Ripple phenomenon of displays with nematic liquid crystal
(2013-04-01)
Lee, Yu-Jung
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Liu, Tzong-Shi
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Lee, Yu-Ching
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機械工程學系
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Department of Mechanical Engineering
Liquid crystal displays will show ripple if the display surface or display bracket is subjected to tactile forces. In this paper, the ripple of liquid crystal displays is investigated by dealing with elastic wave propagation in a liquid crystal layer. The model proposed for a visco-elastic medium like liquid crystals (LCs) is generalized by combining the properties of a crystalline solid and an anisotropic fluid. The governing equation is derived by using visco-elastic and wave equations. In the experiments, a linear motor is used to touch the display panel for producing ripple. Displays of three different amounts of LCs are compared. Experimental results also show that each display panel has its own wave propagation velocity that is not changed by different motor touch speeds. In addition, both theoretical analysis and experimental results depict that displays with a larger amount of LCs lead to slower ripple speed.
Transparent electrodes based on conducting polymers for display applications
(2013-10-01)
Wang, Pen-Cheng
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Liu, Li-Hung
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Mengistie, Desalegn Alemu
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Li, Kuan-Hsun
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Wen, Bor-Jiunn
The materials science and engineering related to the fabrication of conducting polymer thin films and the progress in the development of devices integrated with organic transparent electrodes based on conducting polymers for display applications are reviewed. Transparent electrodes are essential components for many display modules. With the evolution of display technologies, conducting polymers are recently emerging as important alternative materials for the fabrication of transparent electrodes. Conducting polymers offer some advantages, such as light weight, low cost, mechanical flexibility and excellent compatibility with plastic substrates for the development of next-generation display technologies and, in particular, are expected to play an important role in the development of flexible display technologies. (C) 2013 Elsevier B.V. All rights reserved.
Uncertainty Analysis on Precision Measurement for Polystyrene Nanospheres Using Dynamic Light Scattering
(2010)
Pan, Shan-Peng
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Weng, Han-Fu
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Lin, Chih-Min
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Liu, Tzong-Shi
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機械工程學系
Dynamic light scattering (DLS) is the most commonly used technique for measuring nanosphere sizes. In order to establish the traceability of the DLS method to SI units, relevant parameters have been measured in this study. Several studies have been reported on error sources in DLS. However, these studies lacked a systematic method of analyzing the uncertainty of DLS. In this paper we describe the DLS method and present a measurement uncertainty budget. Monodispersed polystyrene latex (PSL) spheres are selected as reference materials in the uncertainty evaluation. The measured nanosphere sizes are 20, 50, 100, 300, 500, and 1000 nm, among which the measurement results of 100, 300, and 500 nm nanospheres obtained using DLS are compared with those for an electrogravitational aerosol balance (EAB) method. The uncertainties for both methods are calculated, and the results of repeated measurements are presented with confidence levels of 95%. (C) 2010 The Japan Society of Applied Physics