Journals >Optics and Precision Engineering
Contents
2009
Volume: 17 Issue 6
48 Article(s)
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Research Article
Experimental facility of line magnetic fluid traveling wave pump
ZHAO Meng, ZOU Ji-bin, SHANG Jing, and QI Ming
The key techniques of the research on magnetic fluid traveling wave pumps are the produc-tion of traveling wave magnetic fields,the design of pump structures,the dynamic characteristics of magnetic fluid, and so on.According to the generation forms of traveling wave magnetic fields, a line magnetic fluid traveling waveThe key techniques of the research on magnetic fluid traveling wave pumps are the produc-tion of traveling wave magnetic fields,the design of pump structures,the dynamic characteristics of magnetic fluid, and so on.According to the generation forms of traveling wave magnetic fields, a line magnetic fluid traveling wave pump is designed and the coupling of a travelling magnetic field with a force field in the magnetic fluid is analyzed by a decoupling method. Experiment results indicate that the magnetic fluid flux has a direct relation with the magnetic field under the effect of traveling wave magnetic field.The bigger the magnetic field is, the more the flux is, when the structure of the magnetic fluid travellig pump and the saturation magnetization of magnetic fluid are constant. The volumes of the magnetic fluid from the travelling wave pump increase from 1.9 ml to 3.1 ml, when the magnetic field intensity increases from 25 900 A/m to 40 000 A/m.In addition,the change rate of the magnetic fluid decreases with the increase of the magnetic field due to the effect of magnetic field on magnetic fluid viscosity. The bigger the saturation magnetization of the magnetic fluid is, the more the flux is..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1213 (2009)
Micro direct methanol fuel cells based on silicon and non-silicon MEMS techonlogies
TANG Xiao-chuan, ZHANG Yu-feng, YUAN Zhen-yu, WANG Xi-lian, and LIU Xiao-wei
Two kinds of micro Direct Methanol Fuel Cells(μ-DMFC)characterized by simple configurations,small sizes and high specific power densities are presented by using silicon and stainless steel as poles in this paper.The working principle and structure of the μDMFC are introduced. Then,the silicon μ-DMFC is accomplished usiTwo kinds of micro Direct Methanol Fuel Cells(μ-DMFC)characterized by simple configurations,small sizes and high specific power densities are presented by using silicon and stainless steel as poles in this paper.The working principle and structure of the μDMFC are introduced. Then,the silicon μ-DMFC is accomplished using Micro Electro Mechanic System(MEMS) technologies such as lithography, depositing and etching. Experimental results show that the open circuit voltage is 520 mV and the peak power density can reach 5.9 mW/cm2 for the silicon μ-DMFC at room temperature when the molar concentration of methanol solution is 1.5 mol/L. Moreover, the stainless steel μ-DMFC is fabricated using a non-silicon micromachining technology,and it can offer an open circuit voltage of 650 mV and a peak power density of 15.8 mW/cm2 un-der the 2 mol/L methanol solution at room temperature. It is concluded that the performance of the stainless steel μ-DMFC is greatly better than that of the silicon μ-DMFC..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1218 (2009)
Design of fuze MEMS electrostatic detection array
HAO Xiao-hui, XU Li-xin, CUI Zhan-zhong, and CHEN Xi
The motion of a target in air will produce electrostatic fields which can be detected by a fuze to provide some useful information of the target. Moreover, MEMS devives have shown their characteristics of small sizes, low power consumption and high integration to be suitable for design of MEMS electrostatic detection aThe motion of a target in air will produce electrostatic fields which can be detected by a fuze to provide some useful information of the target. Moreover, MEMS devives have shown their characteristics of small sizes, low power consumption and high integration to be suitable for design of MEMS electrostatic detection arrays. When a MEMS electrostatic detecion array is placed in the limited space of a fuze, the array can acquire the information of position and velocity of the target by detecting electric field around it.A MEMS electrostatic field detection array with a vibrating film is designed using surface machining processes in this paper.The princile and fabrication of the electric field detection arrat are systematically presented and the processing thchniques of a electrostatic field sensor are explained particularly. The principle and formula of target locating are also studied. The results show that the electrostatic field of the target can be detected by using three MEMS electrostatic detectors, and the positions of the point target along the axis of the projectile and vertical to the axis of the projectile can be obtained. It is concluded that the MEMS electrostatic detection array can locate exactly the target..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1223 (2009)
Comparative analysis of Sigma Delta modulation and pulse code modulation in micro-accelerometer
TAN Xiao-yun, ZHOU Xian-zhong, JIANG Yi-ming, and CHEN Wei-ping
A comparative study of the Sigma Delta Modulation(SDM)and the Pulse Code Modulation(PCM) is presented, and the advantages and the disadvantages of the two kinds of modulation are also obtained. A 2-bit SDM simulated system and a 2-bit (PCM) simulated system for a micro-accelerometer are established in this paper. Then,A comparative study of the Sigma Delta Modulation(SDM)and the Pulse Code Modulation(PCM) is presented, and the advantages and the disadvantages of the two kinds of modulation are also obtained. A 2-bit SDM simulated system and a 2-bit (PCM) simulated system for a micro-accelerometer are established in this paper. Then, the accelaration signals pass through the modulations are comparatively analyzed, and the difference of two mudulations output waves is obtained by the comparive analysis, Finally, the power spectral density patterns of two kinds of the modulated signals are com-puted with a periodogram respectively. The power spectral density from experimental results indicates that the quantization noise of the PCM is more serious than that of the SDM in the low frquency, but the quantization noises of both modulation methods are the same in the high frequency. The simulated results show that the SNR of the SDM is 20 dB higher than that of the PCM, though the SDM modulation system is more complex than the PCM..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1228 (2009)
Design of MEMS microwave power coupler based on GaAs for Ku-band
ZHU Qiu-yao, and LIAO Xiao-ping
A novel MEMS microwave power coupler based on GaAs for Ku-band(12.4～18 Ghz) is presented to improve the existing technology for measuring microwave power based on the termination devices, such as thermistors, thermocouples, and diodes,because the signals are not available after power detection by these devices. By the A novel MEMS microwave power coupler based on GaAs for Ku-band(12.4～18 Ghz) is presented to improve the existing technology for measuring microwave power based on the termination devices, such as thermistors, thermocouples, and diodes,because the signals are not available after power detection by these devices. By the designed coupler, the microwave power is coupled with the Coplanar Waveguide(CPW)line, and most of the CPW signals can be transmitted to the next stage circuit for further processing. In order to reduce the reflection losses and to obtain broadband response of the power sensor, two kinds of optimal methods with a tuned structure and a compensating capacitor are proposed. Optimizations of the design with HFSS has demonstrated that the return loss(S11) and insertion loss (S21) at the central frequency of 15.2 GHz have reached -42.90 dB and -0.15 dB, respectively and the deviation of S11 and S21 compared with the central frequency have reached ±6.41 dB and ±0.04 dB in the Ku-band.These results show the microwave power coupler has advantages of dB and ±0.04 dB in the Ku-band.These results show the microwave power coupler has advantages of high isolation, low loss and broadband characteristics..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1233 (2009)
Steaby electroosmotic flow in diverging microchannels
WANG Xiao-zhang, WANG Chao-hui, and JIANG Zhuang-de
The electroosmotic flow drives a fluid passing through microchannels by an applied electric field,which also induces heat transfers both in the fluid and channel walls because of a Joule-heating. Using the Computing Flow Dynamics(CFD) technique,a flow field and a temperature field in diverging channels are numerically The electroosmotic flow drives a fluid passing through microchannels by an applied electric field,which also induces heat transfers both in the fluid and channel walls because of a Joule-heating. Using the Computing Flow Dynamics(CFD) technique,a flow field and a temperature field in diverging channels are numerically investigated with a 3-D microchip model. Due to the temperature-dependent physical properties of the fluid including viscosity,relative dielectric constants,electric conductivity,and thermal conductivity,the induced temperature gradient imposes great influence on flow behaviors of channels. The results suggest that a nonuniform gradient thermal field is formed in a microchip by the Joule heating and it affects the flow field severely. This gradient thermal field has increased the flow velocity in uniform cross-section channels but can not do it similarly in diverging channels,so that the outlet velocity and volume flow rate have decreased by 16 % and 60 μl/min,respectively.Moreover,the Joule heating also weakens the pumping performance of diverging channels by decreasing the flow velocity and pressure..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1238 (2009)
Compact band reject filter for micro electromechanical systems
HUANG Chuang, CHEN Di, CHEN Xiang, LIU Jing-quan... and LI Hong-qiang|Show fewer author(s)
In order to filtrate the microwave signals in micro electronic mechanical systems,a micro Composite Right/Left Handed(CRLH) transmission line band reject filter is presented,and the design theory,structure characteristics and fabrication process of the filter are also studied. According to the Left Handed Material (LHMIn order to filtrate the microwave signals in micro electronic mechanical systems,a micro Composite Right/Left Handed(CRLH) transmission line band reject filter is presented,and the design theory,structure characteristics and fabrication process of the filter are also studied. According to the Left Handed Material (LHM) theory,the filter structure with a meander gap is introduced,and the equivalent circuit of the meander gap structure is obtained by comparing to the conventional interdigital capacitor structure. Then,the advantage of the meander gap structure is discussed by taking a cell of the meander gap as an example,and the results show that the equivalent circuit parameters in the meander gap structure are larger than that of the conventional interdigital capacitor structure. Finally,the fabrication process is introduced by combining different MEMS (Micro Electromechanical Systems) technologies,such as sputtering,lithography,electroplating and etching. By the MEMS technology,a band reject filter with the size of the main part of 5 mm×7 mm is developed. The simulated and experimental results show that the phase shift constant of the band reject filter is negative at the high frequency (2.1-5.2 GHz,left handed region),and the phase velocity flows just to the opposite direction of the energy flow in the left region. Moreover,the relative pass bandwidth in a left handed region is 82.7%. Compared with other designs,this filter shows his advantages in small sizes and large working bands at the left handed region..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1244 (2009)
Design of thin film bulk acoustic resonator under unique mode
MO Shao-meng, CHEN Jian-ming, WU Guang-min, and ZHAO Jian-jun
The spectra of input electric impedance for a four-layer (electrode/piezoelectric film/electrode/substrate) thin Film Bulk Acoustic Resonator (FBAR) with the materials of Al/AlN/Al/Si and the thickness of each layer of 0.8 μm/1.9 μm/0.8 μm/100 μm is researched by a transfer matrix method. The distribution of the effectThe spectra of input electric impedance for a four-layer (electrode/piezoelectric film/electrode/substrate) thin Film Bulk Acoustic Resonator (FBAR) with the materials of Al/AlN/Al/Si and the thickness of each layer of 0.8 μm/1.9 μm/0.8 μm/100 μm is researched by a transfer matrix method. The distribution of the effective coupling factor (k2eff) versus the mode order is derived,and a unique mode with maximum k2eff is obtained in the 40th mode from 1 GHz to 2 GHz in simulation. The effects of various electrodes and the substrates on the distribution of unique mode and the frequency shift are studied,and the quality factor at series resonant frequency and the Figure of Merit (FOM) which are the main parameters to indicate the features of the crystal resonator in a filter design are investigated.Experimental results show that the performance of the FBAR working in the unique mode relies greatly on the sizes and the materials of layers. The unique mode shifts in a higher frequency are from 1.2 GHz to 4.8 GHz when the film thicknesses come from 0.2 μm to 4.3 μm in simulation; the k2eff and Qs are from 3.2% to 0.8% and from 2 000 to 700 in simulation,respectively when the substrate becomes thicker and the k2eff of the unique mode declines and tends to a stable value when the electrode becomes thicker.These conclusion gives some guidelines for the design of a proper FBAR..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1251 (2009)
LOW-g micro inertial switch based on Archimedes′spiral
CHEN Guang-yan, WU Jia-li, ZHAO Long, and WANG Chao
The low-g inertial switch is a kind of inertial device sensitive to the linear acceleration and achieves the switch closure when subjects to the applied acceleration。Due to its micro size,the switch is designed as a structure with the micro mass and low stiffness. To achieve a low stiffness beam in a micro plane,the plThe low-g inertial switch is a kind of inertial device sensitive to the linear acceleration and achieves the switch closure when subjects to the applied acceleration。Due to its micro size,the switch is designed as a structure with the micro mass and low stiffness. To achieve a low stiffness beam in a micro plane,the planar spiral beam based on Archimedes′spiral is designed. The inertial switch is composed of a substrate,a frame structure,a cover plate and an inertial sensing element containing a sensor mass and a spiral beam.After analysing the inertial sensing element with an ANSYS and fabricating with an UV-LIGA,the laboratory centrifuge tests are performed on the low-g inertial switch to measure the on-state threshold. The result of the test is 21.27g,which is the average of 21.22,21.39,and 21.20g. It is shown that the low-g mechanical inertial switch has a closed precision of 0.5g and good repeatability in multiple tests..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1257 (2009)
MEMS hybrid power-generator from vibration energy
ZHANG Yang-jian, and SAN Hai-sheng
A hybrid vibration-powered microgenerator has been presented by combining the structures of piezoelectric generator and electrostatic generator,and the structure of the microgenerator is optimized by a Finite Element Method(FEM) to obtain the desired low resonant frequency. Then,an analytic model is established to predA hybrid vibration-powered microgenerator has been presented by combining the structures of piezoelectric generator and electrostatic generator,and the structure of the microgenerator is optimized by a Finite Element Method(FEM) to obtain the desired low resonant frequency. Then,an analytic model is established to predict the behavior of the hybrid power-generator and a MATLAB/SIMULINK is utilized for the numerical simulation. The simulated results reveal that the hybrid power-generator has a higher output power than those of two energy harvesting mechanisms at a special resonant frequency. For a resonant frequency of 282 Hz,the simulation result shows the output power from the hybrid mechanism is 4.85 μm,which doubles 2.11 μW from the original capacitive mechanism..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1262 (2009)
Fabrication of metal micro-precision sieves with high open areas using UV-LIGA process
MING Ping-mei, ZHU Di, ZHOU Feng, HU Yang-yang, and ZENG Yong-bin
The manufacture of thick micro-precision sieve-sheets with high open areas is a key technical challenge. After analysis on the process limitations existing in three manufacturing methods for metal micro-precision sieves,an optimized UV-LIGA technique based on SU-8 photoresist is presented to manufacture the micromesh nThe manufacture of thick micro-precision sieve-sheets with high open areas is a key technical challenge. After analysis on the process limitations existing in three manufacturing methods for metal micro-precision sieves,an optimized UV-LIGA technique based on SU-8 photoresist is presented to manufacture the micromesh nickel sieve-sheets. Operational parameters of some key process steps for fabricating micro-precision sieve-sheets are determined experimentally,and morphological characteristics of electroformed hexagon micromesh nickel sieves are evaluated using a SEM and an optical profiler. Experimental results show that,using the UV-LIGA process,hexagon micromesh nickel sieves (200 μm in side length,50 mm in diameter and 120 μm in thickness) with an open-area percent of 88% and a sheet-thickness of 120 μm,which can hardly be achieved by the conventional machining methods,are successfully machined. The machined sieves are characterized by their smooth surfaces and aperture walls,high precision sizes as well as rigid and homogeneous structures.These results show that the UV-LIGA is an excellent method for fabricating micro-precision metal sieves..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1267 (2009)
Noise analysis of special-gas IR detector
XU Chen, DAI Tian-ming, SONG Yi-chao, LI Xiao-bo, and DENG Chen
The noises of a special gas IR detector fabricated by MEMS mainly include the temperature-fluctuation noise,mechanical-thermal noise and the background noise. Based on thermal conduction theory,a thermal model is built up to get the effective thermal content and the effective thermal conductivity to be 1.0×10-3 W/The noises of a special gas IR detector fabricated by MEMS mainly include the temperature-fluctuation noise,mechanical-thermal noise and the background noise. Based on thermal conduction theory,a thermal model is built up to get the effective thermal content and the effective thermal conductivity to be 1.0×10-3 W/K and 8.1 μJ/K,respectively ,and the temperature-fluctuation noise is nearly 1.73×10-10 W/Hz1/2. According to the device operating principle and energy equipartition theory of thermodynamics,the mechanical-thermal noise is 9.96×10-9 W/Hz1/2,and the background noise is nearly 3.22×10-11 W/Hz1/2,so that the normalized detectivity is deduced to be 9.03×106 cm·Hz1/2/W. Experiment results show that the mechanical-thermal noise coming from the structure and the mechanical performance of a heavily doped Si membrane is the main noise of the device,which can be reduced by minishing the membrane area and extending the membrane thickness to increase the mechanical resonant frequency of the membrane,but should be at the price of reducing the sensitivity of the device. The vibration of environment also influences on the device a lot. To decrease the noise coming from the fluctuation of air pressure and the temperature fluctuation of the surrounding,a new double-cell counteracting structure is presented..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1274 (2009)
Silicon micromachined resonant accelerometer based on ZnO nanowire
CHEN Guo-wei, and ZHU Rong
A design and fabrication method for a silicon micromachined resonant accelerometer based on a zinc oxide (ZnO) nanowire is reported. The key and sensitive element of the accelerometer is a nanowire-based resonator with a single ZnO nanowire suspended across two micromachined Cr/Au electrodes. A dielectrophoresis techniA design and fabrication method for a silicon micromachined resonant accelerometer based on a zinc oxide (ZnO) nanowire is reported. The key and sensitive element of the accelerometer is a nanowire-based resonator with a single ZnO nanowire suspended across two micromachined Cr/Au electrodes. A dielectrophoresis technique is used to assemble the ZnO nanowire onto electrodes,then a Focused Ion Beam (FIB) is employed to deposit Pt on the contact between the nanowire and electrodes to clamp the nanowire and eliminate the Schottky barriers at the interfaces. When an external acceleration is applied,the inertial force generated by the proof mass imposes a stress on the nanowire through the beams that support the suspended proof mass. Consequently,the acceleration is associated with the shift in the resonant frequency of the nanowire. By its quasi-digital output,the trouble in detecting feeble analog signals from most MEMS devices could be averted. Experimental results show that the sensitivity of the accelerometer increases dramatically with the decrease of the nanowire's thickness. In the design,nanowire with a thickness of 500 nm is selected for the theoretical analysis,and the sensitivity of the acceleration sensor is estimated to be more than 2.5 kHz/g..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1279 (2009)
Handwriting detecting system for space pen
WANG Wei, LI De-sheng, GAO Zong-yu, ZHOU Wei, and ZHANG Peng-fei
A handwriting detecting system based on micro-accelerometers and micro-gyros is proposed,and the algorithm of the detecting system is also described in detail. The micro-accelerometers and micro-gyros mounted on the pen are used in this dynamic handwriting acquisition system to acquire the dynamic information,and obtaiA handwriting detecting system based on micro-accelerometers and micro-gyros is proposed,and the algorithm of the detecting system is also described in detail. The micro-accelerometers and micro-gyros mounted on the pen are used in this dynamic handwriting acquisition system to acquire the dynamic information,and obtained data are transmitted to computer for data processing and feature analysis through a serial port after A/D conversion.The motion track of the pen in the 3-D space can be recognized through computing the matrix of attitude angles and the dynamic information of the pen is mapped on the 2-D plane. Then,the information of handwriting can be recurred on the writing plane by an integral. Finally,this paper introduces the influence of gravity acceleration on the handwriting recurrence in the movement of the pen,gives a solution to get pure movement acceleration from the gravity acceleration detected by the micro-accelerometer,and describes the sensor calibration method. Experimental results prove the designed system to be feasible..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1286 (2009)
Numerical simulations on over-plating by deformed meshes
ZHU Xue-lin, WANG Xiang, and CHU Jia-ru
The electrical deposition in an over-plating technology was explored under different line spaces and line widths and the effect of geometries,such as a line space/line width ratio,and the deposition velocity during the over-plating was investigated by using numerical simulations. Then,the deformed meshes were also applThe electrical deposition in an over-plating technology was explored under different line spaces and line widths and the effect of geometries,such as a line space/line width ratio,and the deposition velocity during the over-plating was investigated by using numerical simulations. Then,the deformed meshes were also applied to suit to the boundary grows of plated microstructure with the deposition. The numerical results indicate that the difference of deposition velocity between the two adjoined plating lines is small and the depositing velocitie of the lateral and vertical directions are almost the same when the ratio of line space to line width is larger than 12. But the depositing in lateral direction will be constrained when the ratio of line space to line width is smaller than 6. The deposition can stop in a hole between the two plated lines and can cause the plating defect,for the smaller the line space/line width is,the bigger the ratio of leteral deposition velocity to vertical deposition velocity is. Experiments also show that the plating defect mentioned above can be removed by a technical method using a second seed layer on photoresist..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1293 (2009)
Design and fabrication of floating electrode unidirectional SAW actuator
ZHANG Jun-feng, LI Yi-gui, and HUI Chun
Surface Acoustic Wave(SAW) actuators have been dramatically required for a micro actuator not only due to their direct driving objects,low energy losses and drive errors,but also their higher work frequencies,shorter SAW waves,small dimensions,and low noises. In this paper,an applicable (SAW) micro actuator is implemenSurface Acoustic Wave(SAW) actuators have been dramatically required for a micro actuator not only due to their direct driving objects,low energy losses and drive errors,but also their higher work frequencies,shorter SAW waves,small dimensions,and low noises. In this paper,an applicable (SAW) micro actuator is implemented by fabricating microelectrodes on a LiNbO3 substrate and by using MEMS technologies.In order to control the drive direction more effectively,a new type of IDT,Floating Electrode Unidirectional Transducer (FEUDT) is developed and the optimal designs are proposed and compared with others by ANSYS. The dimensions of the FEUDT are 5 mm in the aperture size,80 μm in the pitch,6.7 μm in the strip width,and 0.8 μm in the thickness. In comparison with other types of SAW actuators,the floating electrode unidirectional SAW actuator has a higher frequency vibration near to 50 MHz and more effectively controllable drive direction ability,which will be very useful for micro optical controlling systems in microminiaturization and controllability..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1300 (2009)
Dielectrophoretic traps and micro-motor for driving and sorting latex spheres:from discrete devices to a lab-on-a-chip
LIU Yong-hong, ZHAO Zhan, PANG Cheng, and FANG Zhen
This paper reports dielectrophoretic traps and a micro-motor for driving and sorting latex spheres on a chip with complex structures. A scheme containing function modules for pre-separating,sorting and driving micro-particles in a single chip is proposed. In order to optimize the system design,comparative researches onThis paper reports dielectrophoretic traps and a micro-motor for driving and sorting latex spheres on a chip with complex structures. A scheme containing function modules for pre-separating,sorting and driving micro-particles in a single chip is proposed. In order to optimize the system design,comparative researches on various electrode geometries of discrete devices from different separation principles are undertaken. Different from the obtained results before,the electrode shapes of all parts have been modified,which makes the dielectrophoresis effects better than those of traditional approaches. Moreover,a novel spiral interdigital or a spiral-castle electrode is used to replace the old spiral electrodes,and more than 90% target particles can be obtained. The separation voltage signal also can be decreased by 50% while using a standing wave instead of a conventional traveling wave. Otherwise,the lateral or axial inhomogeneously castellated electrode is constructed,by which 70% target particles can be sorted. Moreover,for the dielectrophoretic micro-motor composed of a coplanar and quadrupolar electrode structure,it is observed that annular array shaped electrodes in the center can make the device obtain high rotation speed under a low voltage condition..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1306 (2009)
CMOS interface circuit for closed-loop accelerometer
YIN Liang, CHEN Wei-ping, LIU Xiao-wei, and ZHOU Zhi-ping
An 18 V switched-capacitor CMOS interface circuit for the closed-loop operation of a capacitive accelerometer is designed. The circuit consists of a switched-capacitor charge sense amplifier,a PID control circuit and a correlated double sampling circuit. The effects of the 1/f noise of the amplifier and the offset voltAn 18 V switched-capacitor CMOS interface circuit for the closed-loop operation of a capacitive accelerometer is designed. The circuit consists of a switched-capacitor charge sense amplifier,a PID control circuit and a correlated double sampling circuit. The effects of the 1/f noise of the amplifier and the offset voltage of an op-amp,as well as the kT/C charge noise from the parasitic capacitor are suppressed,by taking large area PMOS transistors at the Charge Sensing Amplifier(CSA)as an input stage and using a Correlated Double Sampling (CDS ) technique and the 1/f noise,charge injection and clock feedthrough effects in the back-end circuits are eliminated by the technologies of high loop gain and force feedback. Moreover,the strong driving feedthrough is avoided by separating the drive and sense operations in the time domain by using the same electrodes. The designed complete chip with an area of 15.2 mm2 is fabricated in a 2 μm two-metal and two-poly n-well CMOS and operated by a single 18 V supply,which can offer a measuring sensitivity of 420 mV/g and a noise of floor of 10 μg/2～1/(Hz) in closed-loop..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1311 (2009)
Image analysis on ICPF actuated micro-robot
NIE Lin, CHEN Wei, LI De-sheng, and CUO Shu-xiang
The Ionic Conducting Polymer gel Film(ICPF) can be driven by a low voltage (about 1.5 V) and has advantages in the less mass and fast response. A micro-robot moved at 3 mm/s velocity in the water can be actuated by the ICPF (21.6 mm×4.6 mm×0.2 mm). An image processing system is designed for detecting and contThe Ionic Conducting Polymer gel Film(ICPF) can be driven by a low voltage (about 1.5 V) and has advantages in the less mass and fast response. A micro-robot moved at 3 mm/s velocity in the water can be actuated by the ICPF (21.6 mm×4.6 mm×0.2 mm). An image processing system is designed for detecting and controlling the movement and posture of the micro-robot,which consists of a CCD camera,an image interface card,a computer and a waveform generator. A movement and posture image sequence of the robot fish is captured by a CCD camera to obtain a binary image of each frame by the hue automatic threshold segmentation and boundary extraction based on the similarity target of in a short period. Then,the target location and movement direction are calculated by the circle detection using improved Hough transform. According to the target location and movement direction,the robot fish posture can be controlled by changing the voltage and frequency of ICPF and by using the waveform generator. Results show that system consumes 52 ms for processing a piece of picture in a Pentium 4 2.8 G computer with 1 G memory and achieves the real-time detection,tracking and control for the micro-robot fish..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1316 (2009)
Reduction of hysteresis for spin valve film by annealing method
LI Wei, LIU Hua-rui, REN Tian-ling, and LIU Li-tian
To reduce the hysteresis of spin valve films is important for fabricating Giant Magnetoresistance(GMR) sensors. This paper reports the experiment results of reducing hysteresis of the spin valve films by using an annealing method and describes numerically simulating annealing conditions and methods. By utilizing the meTo reduce the hysteresis of spin valve films is important for fabricating Giant Magnetoresistance(GMR) sensors. This paper reports the experiment results of reducing hysteresis of the spin valve films by using an annealing method and describes numerically simulating annealing conditions and methods. By utilizing the method of numerical simulating,the annealing conditions and experiment results are simulated. The simulating results show that the numerical simulating can not only optimize annealing conditions,but also decrease a large numbers annealing experiments. Using optimized annealing conditions,the coercive force of the spinvalve film is reduced enormously but the Magnetoresistance(MR) of the spinvalve film can be kept a higher level. An annealing experiment and different annealing parameters show that the coercive force and MR of the spinvalve film respectively is 358.2 A/m and 9.24% before annealing,but they have increased to 3.18 A/m and 8.54% after annealings,which proves the numerical simulating method is conductive to the improvement of the annealing conditions..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1322 (2009)
Design of piezoelectric power generator in tire
LIAO Hai-yang, and ZHONG Zheng-qing
A novel power generator in the tire which is applied in a wireless Tire Pressure Monitor System(TPMS) was designed. The piezoelectric convertor constructed by bender arrays was merged to the inner surface of a tire to transform the mechanical deformation into the electric power and supply to the sensors of TPMS. A FiniA novel power generator in the tire which is applied in a wireless Tire Pressure Monitor System(TPMS) was designed. The piezoelectric convertor constructed by bender arrays was merged to the inner surface of a tire to transform the mechanical deformation into the electric power and supply to the sensors of TPMS. A Finite Element Model(FEM) for the convertor was established based on the second piezoelectric function and the piezoelectric convertor with different sizes was analyzed by ANSYS 11.0 in a transient method. Then,a target of 6 cm2 was selected to observe its characteristics,and the effective current is 5 μA. As the wireless sending component needs 10 mA every 30 s,an array with 40 piezoelectric convertors was used in the generator and a power conditioning circuit with a multiple path charge coupling module was also designed. Experiments show that when the frequency of tire rotation is 15 Hz,the average power through the conditioning circuit is 150－350 μW and the instantaneous power can reach 50 mW,which proves that the power generator can work efficiently..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1327 (2009)
Tapered slot antenna on micromachined silicon substrate
HOU Fang, ZHU Jian, YU Yuan-wei, and CHEN Chen
A Tapered Slot Antenna (TSA) fed by a Coplanar Waveguide(CPW) on a high dielectric constant substrate (εr=11.9) worked at 35 GHz is presented. The performance of the TSA is sensitive to the effective thickness and electric constant of the substrate. In consideration of thin and fragile features of the high dielectric cA Tapered Slot Antenna (TSA) fed by a Coplanar Waveguide(CPW) on a high dielectric constant substrate (εr=11.9) worked at 35 GHz is presented. The performance of the TSA is sensitive to the effective thickness and electric constant of the substrate. In consideration of thin and fragile features of the high dielectric constant substrate for millimeter-wave application,a series of very closely spaced holes are formed on the substrate by using a deep etch technology,which synthesizes a localized low dielectric-constant environment and increases the effective thickness of the substrate. Otherwise,CPW-to-SLOT transitions with low insertion losses are proposed to feed this antenna. The simulation results show that the bandwidth and the gain of the antenna have been achieved 28.2% and 8.7 dB,respectively. After using micromachining technologies,the measured result shows the bandwidth is 13.2%. The difference between simulation and measurement is mainly attributed to the improvement for fabrication errors and measurement loads. This CPW-fed TSA has been expected to apply to communication systems for its easy integration with the uniplanar monolithic millimeter-wave integrated circuits..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1333 (2009)
Development of ion-drag EHD micropump
YU He, ZHANG Qiang, QIAO Da-yong, and YU Jian
A novel electronics cooling system—ion drag Electrohydrodynamic (EHD) micropump was introduced. The ion drag EHD micropump containing a planar electrode array on a silicon substrate was fabricated and tested,in which the electrodes were paired as an emitter and a collector with 40 μm width and 50 μm gap between them,thA novel electronics cooling system—ion drag Electrohydrodynamic (EHD) micropump was introduced. The ion drag EHD micropump containing a planar electrode array on a silicon substrate was fabricated and tested,in which the electrodes were paired as an emitter and a collector with 40 μm width and 50 μm gap between them,the number of electrode pairs was 90 and the gap between two electrode pairs was 100 μm. Static pressure tests were performed by a DC driving voltage and by HFE7100 and ethyl alcohol as working fluids. Experimental results show that the static pressure is quadratic proportion to the input voltage and inverse proportion to the channel height and the maximum pressure head achieved by this micropump is 250 Pa at an applied voltage of 200 V. These data proves that the performance of the ion-drag pump can be improved significantly by selecting the fluid with high permittivity and low viscosity. It also indicates that the cleanness degree of devices and the purification of the working fluid will greatly influence the performance and working lifetime of the EHD micropump..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1338 (2009)
Micro-machined vibrating ring gyroscope
CHEN Li, CHEN De-yong, and WANG Jun-bo
To reduce the frequency split of the drive mode and the sense mode of a vibrating ring gyroscope to improve the performance of the gyroscope,a novel symmetrical structure with electromagnetic driving and detection is proposed in this paper. The Micro-machined Vibrating Ring Gyroscope (MVRG) is fabricated in centro-symmTo reduce the frequency split of the drive mode and the sense mode of a vibrating ring gyroscope to improve the performance of the gyroscope,a novel symmetrical structure with electromagnetic driving and detection is proposed in this paper. The Micro-machined Vibrating Ring Gyroscope (MVRG) is fabricated in centro-symmetric and mirror-symmetric micro structures by MEMS bulk silicon processing with (100) oriented single-crystal silicon,which is conductive to reducing the frequency split. A closed-loop control circuit consisting of a low noise front-end amplifier,a phase shifter and a Variable Gain Amplifier (VGA) is developed to track the drive mode resonant frequency and to stabilize the vibration amplitude of the drive mode. The test results show that the frequency split of drive mode and the sense mode is about 0.27 Hz,which means the frequencies have been matched well. The sensitivity of this gyroscope is 8.9 mV/(°/s) ,the resolution is 0.05°/s and nonlinearity is about 0.23% in the rotation rate ranges of ±200 °/s..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1344 (2009)
Micro integrated pressure,temperature,and relative humidity sensor using adhesive bonding with SU-8
ZHANG Jian-gang, PANG Cheng, FANG Zhen, and ZHAO Zhan
The integrated pressure,temperature,and relative humidity sensors with high precision are highly needed in environmental monitoring and industrial control,for they have the superiorities on small sizes,low weights,low costs and easy to produce. Based on MEMS technology,a novel high precision integrated pressure,temperaThe integrated pressure,temperature,and relative humidity sensors with high precision are highly needed in environmental monitoring and industrial control,for they have the superiorities on small sizes,low weights,low costs and easy to produce. Based on MEMS technology,a novel high precision integrated pressure,temperature,and relative humidity sensor is developed and its design principle and composition are introduced. Then,the fabrication process sequence and experiments for the integrated sensor are given. The 5.5 mm×3.5 mm×0.8 mm sensor chip consists of a piezoresistive Pt pressure sensor using adhesive bonding with SU-8,a Pt resistance temperature sensor and a capacitive humidity sensor.Experiments show that the pressure sensor has a linearity of 0.2% and a precision of 0.05% in square fitting; the temperature sensor has a precision of 0.3% and the humidity sensor shows the wide ranges of sensing ambient relative humidity from 25%RH to 95%RH and a linear correlation coefficient of 0.998 in 28.5 ℃. The high precisions of three sensors indicate the compatibility of the fabrication of this integrated sensor..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1350 (2009)
Driving-mode test of dual-mass MEMS gyroscope
YIN Yong, WANG Shou-rong, WANG Cun-chao, YANG Bo... and TIAN Zhong|Show fewer author(s)
A new dual-mass gyro is studied in this paper,for double-linear vibrational dual-mass MEMS gyroscopes are insensitive to the environment,and their differential outputs can effectively suppress the common mode interference. On the basis of the structure and the principle of operation,the driving modal of the dual-mass gA new dual-mass gyro is studied in this paper,for double-linear vibrational dual-mass MEMS gyroscopes are insensitive to the environment,and their differential outputs can effectively suppress the common mode interference. On the basis of the structure and the principle of operation,the driving modal of the dual-mass gyro is analyzed in theory,and the simplified dynamic equations are proposed. Then,the finite element software ANSYS is used to numerically simulate the driving modal,and a driving circuit is used to test the driving modal of a fabricated gyro sample. By using several loading methods in simulations and tests,the amplitude-frequency curves are obtained. These results are in agreement with the theory analysis,which shows that dual-side driving method is better than single-side driving one,and the opposite-direction driving method can drive a dual-mass gyro in working mode. Simulation and experiment results verify the driving-mode characteristics of this dual-mass micro-gyro..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1350 (2009)
Electromechanical coupling characteristics for force-balanced vacuum microelectronic accelerometer
YANG Yin-chuan, LI Dong-ling, and SHANG Zheng-guo
The inertia sensitive component of a force-balanced vacuum microelectronic accelerometer is effected by both the elastic force and the electrostatic force,and its total stiffness is the sum of the mechanical stiffness of the beams and the equivalent stiffness produced by the electrostatic force. In considerasion of theThe inertia sensitive component of a force-balanced vacuum microelectronic accelerometer is effected by both the elastic force and the electrostatic force,and its total stiffness is the sum of the mechanical stiffness of the beams and the equivalent stiffness produced by the electrostatic force. In considerasion of the effect of emitting tip array,this paper introduces a revised constant α greater than 1 to compute the actual electrostatic force by using the model of a parallel plate capacitor. The analysis shows that the linearity and sensitivity of the vacuum microelectronic accelerometer has been improved by increasing preload deflection voltages,so the stiffness and damping ratio of the system can be adjusted by modulating the voltage between the two deflection electrodes. Considering the affect by a pull-in,the displacement of proof mass must be less than one-third of the original distance between two deflection electrodes. Moreover,in order to obtain good dynamic characteristics,an optimum working point determined by the preload deflection voltage must be set. The experimental results show that the nonlinearity and sensitivity of the accelerometer are 0.95% and 557 mV/g when the deflection voltage and the emission voltage are 5.478 V and 1.953 V,respectively,which indicates that the sensor has good performance..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1361 (2009)
Design of MEMS hybrid energy generator for multi-frequency vibration
REN Jing, and CHEN Xu-yuan
The design,modeling and simulation of a novel MEMS hybrid energy generator for multi-frequency vibration is presented to meet the requirements of portable and wireless electronic devices for collecting energy from the ambient environment. In this design,piezoelectric cantilever beams and capacitors are combined for harThe design,modeling and simulation of a novel MEMS hybrid energy generator for multi-frequency vibration is presented to meet the requirements of portable and wireless electronic devices for collecting energy from the ambient environment. In this design,piezoelectric cantilever beams and capacitors are combined for harvesting the hybrid vibration energy. Then,an analytical model is established for the multi-frequency vibration energy harvesting system and a numerical simulation method is used to predict the power output by using a MatLab/SIMULINK. The result shows that the structure can work efficiently in the frequency ranges of 630-655 Hz,and the power output can reach about 13.46 μW with a load resistance of 50 kΩ. Based on the result,an optimized multi-frequency hybrid energy harvester is designed in this paper. In addition,the Finite Element Analysis (FEA) of the structure is carried out to prevent the structure failure. The work implemented by this paper shows that the next generation design with a wider frequency range and a higher power output within a smaller structure volume is expectant..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1367 (2009)
Fabrication of micro energy director on polymethyl methacrylate substrate for micro ultrasonic bonding
TAO Lin, LUO Yi, ZHANG Yan-guo, ZHANG Zong-bo, and WANG Xiao-dong
In order to use a micro ultrasonic bonding method to package polymer microfluidic chips,an auxiliary microstructure named micro energy director is designed and fabricated on two sides of the microchannel by a selective bonding method in this paper. A hot embossing method is adopted to fabricate this newly designed PolyIn order to use a micro ultrasonic bonding method to package polymer microfluidic chips,an auxiliary microstructure named micro energy director is designed and fabricated on two sides of the microchannel by a selective bonding method in this paper. A hot embossing method is adopted to fabricate this newly designed Polymethyl Methacrylate(PMMA) substrate containing both convex micro energy directors and concave microchannels,then a complex silicon mold is designed and fabricated by the multi-photolithography and wet etching. By the Taguchi method,the optimized parameters for hot embossing are obtained. Experimental results show that the optimized embossing temperature is 15-20 ℃ higher than that of the simply replicate concave microstructure,since concave and convex micro structures are formed simultaneously. With the optimized parameters in an embossing temperature of 140 ℃,holding time of 300 s,and an embossing pressure of 1.65 MPa,the accuracy of replication can be up to 99%..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1373 (2009)
Design of interface circuit of closed-loop accelerometer with self-test function
LIU Ynu-tao, YIN Liang, CHEN Wei-ping, and WU Qun
A low-noise closed-loop interface circuit based on a switched-capacitor is presented to improve the noise performance of a MEMS capacitive accelerometer. A charge integrator is adopted as pre-amplifier,which is insensitive to parasitic capacitance and has a very low noise level. The Correlated Double Sampling (CDS) tecA low-noise closed-loop interface circuit based on a switched-capacitor is presented to improve the noise performance of a MEMS capacitive accelerometer. A charge integrator is adopted as pre-amplifier,which is insensitive to parasitic capacitance and has a very low noise level. The Correlated Double Sampling (CDS) technique is applied to eliminate the 1/f noise and the offset of an operational amplifier. Meanwhile,in order to improve dynamic response performance,an integration circuit is introduced to enhance the damping ratio of system and to increase the response speed. The self-test function is also realized by utilizing the same route with charge-discharging. Finally,an elaborate layout design with 0.5 μm CMOS process is completed. The post-simulation results indicate that the sensitivity of the system is 0.115 V/g,nonlinearity is less than 0.12%,minimum acceleration detected can be up to 20μg and the self-test output is proportional to the self-test voltage..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1379 (2009)
Capacitive pressure sensor with circular island structure
ZOU Li-ming, and GUO Hang
A capacitive pressure sensor with a new movable electric plate structure is presented to improve the output nonlinearity of a MEMS-based capacitive pressure sensor. The movable plate of the sensor is a rectangular memrance made of LPCVD silicon nitride film,and a circular island is added from the center to the edge of A capacitive pressure sensor with a new movable electric plate structure is presented to improve the output nonlinearity of a MEMS-based capacitive pressure sensor. The movable plate of the sensor is a rectangular memrance made of LPCVD silicon nitride film,and a circular island is added from the center to the edge of the membrane by depositing and patterning a layer of PECVD silicon dioxide. With this structure,the deformation of the movable plate of the capacitive pressure sensor will tend to flat when applying a load of pressure,so that the nonlinearity of stray capacitance near the edge of the entire structure is decreased and the output properties of the sensor is improved. Moreover,the Finite Element Model( FEM) in ANSYS is used to analyze the new structure of the movable electrical plate with different dimensions to obtain the relationship between deflection and pressure and the corresponding stress distribution and a curve fitting based on the least-square method is applied to calculate the output linearity of the sensor. Comparison of the MEMS-based capacitive pressure sensor with a general structure sensor,the output linearity of the proposed sensor has been improved by 48.38%,reaching 1.6%..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1385 (2009)
Design of heater integrated into micro direct methanol fuel cell
ZHANG Qian, WANG Xiao-hong, and ZHENG Xiang
The heat transfer model of a micro Direct Methanol Fuel Cell (μDMFC) based on heat transfer mechanisms is presented. Three kinds of patterns of the heater integrated into a μDMFC are designed and simulated using the Finite Element Analysis (FEA). The simulation results illustrate that the different patterns of the heatThe heat transfer model of a micro Direct Methanol Fuel Cell (μDMFC) based on heat transfer mechanisms is presented. Three kinds of patterns of the heater integrated into a μDMFC are designed and simulated using the Finite Element Analysis (FEA). The simulation results illustrate that the different patterns of the heater cause different temperature distributions on the surface of the plate,which would induce different heating effects on a fuel cell and great influence on its performance. According to the results,an ideal heater resistance which causes a maximum temperature contrasts of 1.4℃ is applied to control the operating temperature in experiments,for it shows an improvement on the temperature uniformity.Moreover,the heaters with other two patterns produce the maximum temperature contrast of 2.1℃ and 3.0℃,respectively. Experimental results show that the μDMFC can generate a maximum power density of 5.55 mW/cm2 at a temperature of 58.2℃ when a current of 53.9 mA is applied to the heater. This work would make it possible for a μDMFC to enhance the performance by adjusting to the temperature and to employ it in extreme environments..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1391 (2009)
Variable-focus liquid lens with suspended conical ring
SUN Kai-ge, KANG Ming, OU-YANG Fan, and YUE Rui-feng
A novel configuration of variable-focus liquid lens based on an electrowetting-on-dielectric technique is presented,which consists of a glass slide coated with a conductive Indium Tin Oxide (ITO) film,a hydrophobic dielectric film,a hollow conical metal ring suspended right above a gap between the slide and the ring,anA novel configuration of variable-focus liquid lens based on an electrowetting-on-dielectric technique is presented,which consists of a glass slide coated with a conductive Indium Tin Oxide (ITO) film,a hydrophobic dielectric film,a hollow conical metal ring suspended right above a gap between the slide and the ring,and the lens liquid (water). By changing the voltage applied to a grounded metal ring and a ITO control electrode,both the position and curvature of the liquid meniscus can be reversibly adjusted,and the focal length of the lens can be tuned. The shapes of the suspended ring in the present work are also designed to self-center the lens liquid,then influences of different shapes of the suspended rings on the variation of optical power of the meniscus are discussed. Experimental results show that the liquid lens at a good imaging quality is able to focus on objects away from 2.5 cm up to infinity at a 40 V power supply and also able to offer the variation range of the optical power up to 40m-1. Because of the properties such as low consumption,small sizes and high reversibility and so on,the demonstrated configuration provides great advantages in the field of microlens..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1397 (2009)
Role of configurational entropy in molecular sieving through nanofilter arrays
LI Zi-rui, LIU Gui-rong, HAN Jongyoon, WANG Jian-sheng, and CHEN Yu-zong
This article proposes a theoretical model of molecular sieving through repeated nanofilter arrays consisting of alternative deep and shallow regions. The role of configurational entropy,which arises from the inaccessibility of some configurations of the molecule in the confined space of nanochannel,is clarified expliciThis article proposes a theoretical model of molecular sieving through repeated nanofilter arrays consisting of alternative deep and shallow regions. The role of configurational entropy,which arises from the inaccessibility of some configurations of the molecule in the confined space of nanochannel,is clarified explicitly. It is demonstrated that the configurational entropy difference of anisotropic biomolecules of different sizes dominates the complex partitioning of these molecules over the nanofilter array. In addition,the relationship between the effective mobility and the nanofilter geometries,molecular transport parameters,and the strength of electric fields are described rigorously.As an example,the mobilities for 50,150 and 300 bp DNA molecules are calculated using this model,which matches the experimental data with a error less than 5%. This simplified model allows for fast analysis of nanofilter separation systems,without the need of complicated numerical simulations and physical experiments..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1403 (2009)
Thermal effect on equivalent spring constants of double-clamped beams with different mass arrangements
WU Kang, YE Xiong-ying, LIU Li-tao, DU Min, and ZHOU Zhao-ying
Thermal effect on the equivalent spring constants of double-clamped beams (bridges) with two kinds of mass arrangements including central mass and side mass were studied by theoretical analysis and finite element simulation. An equation to describe the change of the equivalent spring constants of beams due to temperatuThermal effect on the equivalent spring constants of double-clamped beams (bridges) with two kinds of mass arrangements including central mass and side mass were studied by theoretical analysis and finite element simulation. An equation to describe the change of the equivalent spring constants of beams due to temperature variation was derived and the equivalent spring constants from simulation results of the fundamental vibration frequency and the displacement under a static load were obtained respectively by the finite element analysis. Results show that the temperature variation has an important effect on the equivalent spring constants.For the fundamental vibration frequency,there are a good agreement between the derived equation and the vibration simulation results for the both structures. For the displacement under a static load, the asymmetry in mass arrangement results in the bending of the beam when temperature shifts,and the bending causes a displacement of the mass to the side. As a result, the asymmetric arrangement of mass changes the initial displacement of mass when temperature varies, which would cause the changes of output signals for Micro Electro Mechanic System (MEMS) sensors or actuators..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1409 (2009)
Design and fabrication of bulk micromachined tunneling gyroscope with fan-shaped comb drivers
WANG Ling-yun, LI Wen-wang, ZHUANG Gen-huang, and SUN Dao-heng
A bulk micromachined vibratory tunneling gyroscope which employs the high displacement sensitivity of quantum tunneling to obtain the desired resolution has been developed. The device consists of fan-shaped comb drivers which can oscillate and an out-of-plane silicon cantilever linked up to a substrate suspended by sprA bulk micromachined vibratory tunneling gyroscope which employs the high displacement sensitivity of quantum tunneling to obtain the desired resolution has been developed. The device consists of fan-shaped comb drivers which can oscillate and an out-of-plane silicon cantilever linked up to a substrate suspended by springs. Because of adopting a solid-mass silicon structure to get the larger proof mass, the new ultracompact device can provide extremely high sensitivity and a wide dynamic range. Based on the modal analysis by a Finite Element Method(FEM), the structure dimensions are optimized according to resonant frequency matching of the driving mode and the sensing mode. Simulation results demonstrate that the gyroscope owns the sensitivity of 0.007 nm(°)/s at atmospheric pressure, which also shows the Deep Dry Silicon on Glass (DDSOG) process can be used to fabricate not only the micro-machined tunneling gyroscope but also other sensors and actuators..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1415 (2009)
Preisach modeling of hysteresis for fast tool servo system
WANG Xiao-hui, and SUN Tao
A fast tool servo mechanism with a piezoelectric actuator has attracted more attention for its excellent machining way and high resolution.In this paper, the classical Preisach hysteresis modeling for a Fast Tool Servo (FTS) system subjected to the dynamic voltage excitations is presented. As a universal driving elemenA fast tool servo mechanism with a piezoelectric actuator has attracted more attention for its excellent machining way and high resolution.In this paper, the classical Preisach hysteresis modeling for a Fast Tool Servo (FTS) system subjected to the dynamic voltage excitations is presented. As a universal driving element for the FTS system, the piezoelectric actuator exhibits specific nonlinearity from the hysteresis effect between the displacement and the applied electric field, which is a key factor limiting the dynamic performance of the FTS system. To establish a mathematical model to describe the hesteresis for the FTS system,the numerical expressions of the classical Preisach model are presented in details,and a series of test are conducted to study the hysteresis property and to find out the congruency and wipe-out properties of the FTS system. Finally, the classical Preisach model is applied to simulate the hysteresis behavior of the FTS system. Experimental results indicate that the measured curves are good agrement with the predicted curves,which shows that the classical Preisach model can offer excellent modeling accuracy less than 0.65 μm and can provide many applications for requiring voltage excitation signals with narrow band frequencies..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1421 (2009)
Design and control of dual-stage feed drive system in ultra-precision machine tools
LI Guo, WANG Bo, DONG Shen, and WANG Shi-lei
The design and control of a Dual-stage Feed Drive (DSFD) system on a ultra-precision machine is presented. The DSFD system combining coarse (large stroke) and fine (fine resolution) drive stages in series is designed to provide the desired performance,in which a step motor is used for the coarse motion to obtain the laThe design and control of a Dual-stage Feed Drive (DSFD) system on a ultra-precision machine is presented. The DSFD system combining coarse (large stroke) and fine (fine resolution) drive stages in series is designed to provide the desired performance,in which a step motor is used for the coarse motion to obtain the large stroke and fast response speed, and a piezoelectric micro-actuator for the fine motion to achieve the high resolution and accuracy. A control system for the mechanism is developed based on a multiple model-based switching controller,and a movement distribution module is designed for the motion coordinations of coarse and fine movements. Finally,a experiment is undertaken by controlling both stages separately for the actual position on the DSFD system and a measurement is carried out by a laser interferometer. The experimental results show that the step motor has a working stroke of 90 mm with the displacement resolution of 0.3 μm and the piezoelectric micro-actuator has a working stroke of 40 μm with the positioning accuracy of 0.9 μm. The theoretical and experimental results show the validity of the control algorithm..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1426 (2009)
Design of skylight polarization measurement system
CUI Yan, CAO Nan-nan, CHU Jin-kui, ZHAO Kai-chun, and WANG Ti-chang
According to the principle that light polarization can be expressed with a Stokes vector, a new system to measure the polarized skylight distribution is developed. The system is composed of a computer,a modified equatorial mount,an optical fiber spectrometer and an improved astronomical telescope mounted with a rotatabAccording to the principle that light polarization can be expressed with a Stokes vector, a new system to measure the polarized skylight distribution is developed. The system is composed of a computer,a modified equatorial mount,an optical fiber spectrometer and an improved astronomical telescope mounted with a rotatable linear polarizer. The spectral resolution of this system is 1.4 nm for the measurement when wavelength ranges from 400 nm to 900 nm. Using modified equatorial mount, the system can scan the points of celestial hemisphere at azimuth ranges from 0°to 180° and elevation 0° to 90° at an angular resolution of 2.5°. For a full-angle viewing field of 4.5°, this system can measure the radiance intensity, the Degree of Linear Polarization (DOLP), and the Angle of Linear Polarization (AOLP) of the celestial. The calibration results show that the repeatability of intensity measurements is 99% in spectral ranges from 450 nm to 500 nm, and (95±3)% from 500 nm to 900 nm. The uncertainty of DOLP is less than 2% in spectral ranges from 400 nm to 750 nm, especially 1.2% at 475 nm.The angle error of AOLP is smaller than 2°..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1431 (2009)
Modeling and application of piezoelectric vibration-based power generator
HE Xue-feng, WEN Zhi-yu, and WEN Zhong-quan
The piezoelectric vibration-based power generator is a promising MEMS electricity source to power wireless sensing nodes for the fault diagnosis of rotary machines. In this paper,a piezoelectric vibration-based power generator is designed and the mathematical model of the cantilever piezoelectric generator used in rotaThe piezoelectric vibration-based power generator is a promising MEMS electricity source to power wireless sensing nodes for the fault diagnosis of rotary machines. In this paper,a piezoelectric vibration-based power generator is designed and the mathematical model of the cantilever piezoelectric generator used in rotary mechines is established.Then,the effects of the axial extension force on the stiffness of the beam and the frequency of the generator are analyzed,and the formulas of the frequency, output voltage and output power of the cantilever piezoelectric generator are derived. The output property of the piezoelectric vibration-based generator fixed on a rotary frame is measured.Obtained results show that the maximum output power of the generator is about 35 μW at the rotation frequency about 14.25 Hz. The output power decreases quickly when the rotation frequency deviates from the frequency of the generator..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1436 (2009)
Design of high g piezoresistive micro-accelerometer
LIU Feng-li, and HAO Yong-ping
The change in resistivity caused by the mechanical deformation in a micro-accelerometer was used to design an accelerator to measure physical quantities such as high g acceleration. The process and a solid model were constructed in CoventorWare. With changing the position of a piezoresistive sensing element on the fix-The change in resistivity caused by the mechanical deformation in a micro-accelerometer was used to design an accelerator to measure physical quantities such as high g acceleration. The process and a solid model were constructed in CoventorWare. With changing the position of a piezoresistive sensing element on the fix-end cantilever,the optimizing location of the sensing element as well as the relationship between the output current and the location are obtained by using Finite Element Mothod(FEM) in the MemPZR module. Changing the sensitivity by the same percentage, it is proved that electric conductivity changes are coincident with the sensitivity changes of the element. When 20 kg acceleration is inputted, the potential distribution of piezoresistor device terminals,the corresponding stresses of the piezoresistive element and the current location are also obtained,which testifies the anti-over loading ability from the stress location in the fix-end cantilever..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1442 (2009)
Two and a half dimension hexahedral meshing for MEMS design
YAN Wei, ZHANG Xiao-duo, XU Fan, and XU Bo
A new meshing method is introduced to obtain a hexahedral mesh for three dimension MEMS models. MEMS models are built from 2 dimensional masks according to a process sequence. In most of cases, it leads to layered geometries, whose faces are parallel to the z axis or the (x,y) plane. This paper describes a new algorithA new meshing method is introduced to obtain a hexahedral mesh for three dimension MEMS models. MEMS models are built from 2 dimensional masks according to a process sequence. In most of cases, it leads to layered geometries, whose faces are parallel to the z axis or the (x,y) plane. This paper describes a new algorithm to create two and a half dimension(2.5D) hexahedral meshes for these layered models. By the method, the quadrilateral meshs in the (x,y) plane are generated and hexahedral elements are created by extending these quadrangles along z axis. Compared with popular Sweeping algorithm, it is faster and simpler to generate a hexahedral mesh. The mesh size is the only parameter to input before meshing and it spends less than 10 s for the mesh with 10 000 hexahedron elements, which is 10 to 1 000 times faster than that of the Sweeping method. Meanwhile, it can generate a MEMS model according to fabrication processes, which creates an easy way from 2 dimensional mask to 3 dimensional mesh..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1448 (2009)
Fully digital smart temperature sensor with quartz tuning fork resonator
XU Jun, YOU Bo, LI Xin, and MA Jing
In order to measure temperature in high-precision, a high-performance and fully digital smart temperature sensor is designed, which comprises a quartz tuning fork resonator,an interface with Complementary Metal Oxide Semiconductor(COMS ) and a controlling algorithm for sensor reconfiguration based on the Field ProgrammIn order to measure temperature in high-precision, a high-performance and fully digital smart temperature sensor is designed, which comprises a quartz tuning fork resonator,an interface with Complementary Metal Oxide Semiconductor(COMS ) and a controlling algorithm for sensor reconfiguration based on the Field Programmable Gate Array(FPGA). According to the piezoelectricity effect of a quartz, the thermosensitive cut for the quartz tuning fork resonator and the electrode configuration are analyzed,and the resonant differential equation of the quartz resonator working in a flexural vibrating mode is derived from mechanical vibration. Then,the design principle for the quartz tuning fork temperature sensor is discussed,and the characteristic parameter of temperature sensor is extracted.Finally, the nonlinear error of the sensor is analyzed. The quartz tuning fork resonator is fabricated by a photolithography and an etching technology, in which the frequency output is from the interface IC to FPGA and the special controlling algorithm may easily realize the sensor reconfiguration and the automatic calibration in the field. The experimental result indicates that the sensitivity of this sensor can reach 65×10-6/℃ at the temperature ranges from -20 ℃ to 140 ℃, which guarantees the precision of 0.01 ℃, the resolution of 0.001 ℃, and the response time of 1 s..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1453 (2009)
High temperature pressure sensor for harsh environment
ZHAO Li-bo, and ZHAO Yu-long
In order to solve the pressure measurement problem in harsh environments, such as high temperature above 200 ℃, a special piezoresistive pressure sensor with the ranges of 0～120 kPa is developed based on the Micro Electro-mechanical System(MEMS) and Separation by Implantation of Oxygen(SIMOX) technology. The piezoresisIn order to solve the pressure measurement problem in harsh environments, such as high temperature above 200 ℃, a special piezoresistive pressure sensor with the ranges of 0～120 kPa is developed based on the Micro Electro-mechanical System(MEMS) and Separation by Implantation of Oxygen(SIMOX) technology. The piezoresistive pressure sensor chip consists of a silicon substrate, a thin silicon dioxide layer, an optimized boron ion implantation layer photolithographically patterned on a Wheatstone bridge configuration, a stress matching layer with silicon nitride, a Ti-Pt-Au beam lead layer for bonding gold wires, and a cavity fabricated by the wet etching. A special buried silicon dioxide layer with a thickness of 367 nm is fabricated by the SIMOX technology with the oxygen ion dose of 1.4×1018/cm2 and an implantation energy of 200 keV. The buried SiO2 layer is used to isolate the upper measuring circuit layer from the silicon substrate to avoid the leak-current influence, so the fabricated sensor chip can be used in a high temperature above 200 ℃. In order to improve the stability in the wide temperature range, the temperature compensation methods are studied and carried out, so the Temperature Coefficient of Sensitivity(TCS) and Temperature Coefficient of Offset(TCO) of the compensated sensor are easily obtained to be less than 1×10-4/℃·FS. The calibration results show that the developed high temperature pressure sensor has good performances under 200 ℃ for a linearity error of 0.12%FS, a repeatability error of 0.1%FS, a hysteresis error of 0.12%FS, and the sensor′s accuracy of 0.197%FS. which shows it is able to meet the requirements of modern industry, such as oilcans, wind tunnels, mobiles, petrochemical industry, etc...
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1460 (2009)
Driving microrotor by using optical tweezers
ZHAI Xiao-min, and HUANG Wen-hao
Optical tweezers have been successfully used in various scientific and engineering fields such as optics and microactuators. However, there is still a lack of a sophisticated model for optical tweezers on driving complex microrotors. In this paper, a novel model for optical tweezers is presented to calculate the opticaOptical tweezers have been successfully used in various scientific and engineering fields such as optics and microactuators. However, there is still a lack of a sophisticated model for optical tweezers on driving complex microrotors. In this paper, a novel model for optical tweezers is presented to calculate the optical force and torque based on the moment method. A numerical simulation of this model shows that one of the methods to improve the efficiency of an optical tweezer is to change variant conditions,such as the microrotor's speed is in proportion to the laser's power and has a nonlinear relation with the beam's waist. The other method to improve the efficiency for the optical tweezer is to change the microrotor's configuration. The results show that rotor speed of the microrotor is about 10-7 as large as that of the cross-shaped rotor. Furthermore, through analyzing the force placement, it is convenient to find the main surfaces that the optical forces act on, which can provide a foundation for the design of microrotors in the future. This model also has advantages in flexibility and universality in the optical force simulation of microactuators..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1467 (2009)
Characterization of triaxial piezoresistive high-g accelerometer by Hopkinson bar method
DONG Pei-tao, LI Yuan, WU Xue-zhong, HOU Zhan-qing... and WANG Xiao-feng|Show fewer author(s)
The characterization of a triaxial piezoresistive high-g accelerometer by a Hopkinson bar and a data processing method are discussed. After fixing the accelerometer on the end of a calibration bar, the projectile launched from a barrel strikes the calibration bar at a high speed. The impact propagates in the calibratioThe characterization of a triaxial piezoresistive high-g accelerometer by a Hopkinson bar and a data processing method are discussed. After fixing the accelerometer on the end of a calibration bar, the projectile launched from a barrel strikes the calibration bar at a high speed. The impact propagates in the calibration bar in the form of stress wave, which is recorded by a strain gauge fixed in the middle of the calibration bar. The sensitivity of the accelerometer can be obtained by comparing the output of the strain gauge and the integral of the accelerometer output. Using this method, the sensitivities of the Z-axis element and X-axis element of a monolithic triaxial piezoresistive high-g accelerometer is characterized by (2.18 μV/g)/5 V and (2.15 μV/g)/5 V, respectively. The test results are coincident with the previous results by dropping-bar test system,which shows that the characterization system and the data processing method used in this paper are reliable..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1473 (2009)
Optical sensor for product oil identification
ZHUGE Jing-chang, ZENG Zhou-mo, LU Li, LI Jian, and ZHANG Yu
To improve the existing method to detect the product oil in pipeline sequence transportation, it is necessary to set a new method for product oil identification and detection based on the characteristics that reflect the quality of oil. This paper researches a optical sensor and a new method for product oil identificatTo improve the existing method to detect the product oil in pipeline sequence transportation, it is necessary to set a new method for product oil identification and detection based on the characteristics that reflect the quality of oil. This paper researches a optical sensor and a new method for product oil identification and mixed oil distinguish and calculates the light intensity of the Fresnel reflection occurred at the interface between the product oil and a measuring probe. The product oil and oil mixtures are analyzed by using the principle of energy conservation and the inductor model of an electron cloud . Using the optical sensor, the product oils can be identified exactly, and different oil mixtures can be distinguished from each other successfully in a relative error less than 0.02%. The experimental results provide a theoretical basis for the identification of product oil,which shows that the proposed optical sensor has a great application prospect in analyzing the compositions of oil mixtures and predicting the mixing and diffusing conditions of oil transported in product pipelines..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1479 (2009)
Kinetic people model learning of modified HMM
SU Bo-chao, CHEN Gang, and CHE Ren-sheng
The tracking method based on a people model contributes to realizing the kinetic people tracking for a given video,and it can learn the people model by using much less frames of the video. This paper proposes a learn algorithm for learning the people model in the given video.By using a tree pictorial structure model toThe tracking method based on a people model contributes to realizing the kinetic people tracking for a given video,and it can learn the people model by using much less frames of the video. This paper proposes a learn algorithm for learning the people model in the given video.By using a tree pictorial structure model to represent the detuned generic people in the video, and a modified Hidden Markov Model(HMM) to simulate the motion of people between the two frames of the video, a machine learning method is used to the modified HMM to obtain the estimation of parameter of the modified HMM,and to capture the people model from the video. The learned model consists of different body templates covered with color information. For learning the color of the local parts of the people model by proposed algorithm, an instance-specific model has been obtained. The experiment demonstrates that the kinetic people by proposed algorithm model can be learned with sequences images of 80-90 frames involving people motion,which shows the learning method works well for learning the kinetic people model based on video, and can rapidly learn people models for one or more persons in the video..
Optics and Precision Engineering
- Publication Date: Sep. 20, 2021
- Vol. 17, Issue 6, 1485 (2009)
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