Qing Hua Chen

Coupled-Field Finite Element Analysis of MEMS Compound Electrostatic Actuator by Using the ANSYS Software

MEMS (Microelectromechanical Systems) electrostatic actuators have been successfully applied in a number of areas, including accelerometers, gyroscopes, pressure sensors, and optical devices. In this paper, the actuator optimization of a silicon bulk-micro machined MEMS compound electrostatic actuator of an optical device is discussed. The actuator uses folded-beam structure to enhance the electromechanical performance. The movable block is connected to the compound electrostatic actuator through unequal-height folded-beam springs. The lower-height springs connect the block with parallel plates, and can convert the descending motion of the plates into out-of-plane tilting motion of the block efficiently Additionally, the block is capable of in-plane motion by applying the driving force of the comb-drive actuator through structural connection. ANSYS FEM simulation is used to extract the device electromechanical performance and resonant frequency of the device. By gradually varying the design parameters in ANSYS simulation, the relationship between the actuator electromechanical performance and various design parameters is derived. The curves of actuator electromechanical performance versus beam length and beam height are derived and they are in good agreement with theoretical prediction. From the analysis it is concluded that the actuator behavior strongly depends upon various actuator parameters. By adjusting design parameters, desired electromechanical performance can be obtained. Based on the simulation results, a set of optimized design parameters for the compound electrostatic actuator is decided. The above-proposed MEMS compound electrostatic actuator may be used for many applications, such as optical device and micro-operating.

A Novel Fabrication Technology of Hot Stamping Film

This paper proposes an environmentally friendly energy-saving high-quality laser stamping foil film with particular seam-free feature. The whole idea is to meet the countrys high-end anti-counterfeiting technology, consumer products packaging appearance, high-end gifts demand for the target material. The State Quality Supervision and Testing Center (Guangzhou) detection results shows that it includes many merits such as functionality, security, reliability, ease of use, flexibility, stability and other indicators, the performance meets or exceeds the requirements of enterprise technical conditions.

A Novel Single-Stage LED Driver Based for Interior-Lighting Applications

This paper proposes a novel single-stage LED driver based on SY5814A for interior-lighting applications with high levels of power factor. High power factor is achieved by constant on-time operation mode, with which the control scheme and the circuit structure are both simple. The proposed driver features cost-effectiveness, high circuit efficiency, high power factor, low input current ripples and a reduced components count. A prototype driver is developed to supply a 15W LED interior-lighting module with a 65V output voltage. Experimental results demonstrate the functionalities of the proposed circuit.

High Power Factor LED Driver with Improved Inductance

This paper proposes a novel high power factor LED driver based on SY5800A for interior-lighting applications. High power factor is achieved by using the transformer with back winding coil and the transformer with “sandwich” winding coil. In addition, the proposed driver features cost-effectiveness, high circuit efficiency, low input current ripples and a reduced components count. A sample driver is developed to supply a 15W LED interior-lighting module with a 0.99 power factor. Experimental results demonstrate the functionalities of the proposed circuit.

An Improved Design Method of the MEMS-Based Folded-Beam Micromirror

In this paper, the folded-beam torsion MEMS mirror that meets a set of specified constraints was developed. An optimization algorithm that we newly adopted in the RCS(restricted competition selection) GA(genetic algorithm) could overcome some difficulties in single-search algorithms. Moreover, by the proposed method, the designer’s experience, and view and judgment could be reflected effectively.

Fabrication of the Open-Loop MEMS-Based Tilting Mirror Using the Compound Process

In this paper, a kind of novel open-loop two-stage torsion-mirror optical actuators has been demonstrated. The mirrors are fabricated in SOI wafers, and exhibit good basic electromechanical characteristics. They provide an impetus to being brought into use as optical switches or attenuators, etc. for fiber communication applications.

Design of the MEMS-Based Straight-Beam Micromirror Using a Genetic Algorithm

A system for optimizing the design of a MEMS mirror that meets a set of specified constraints has been developed to optimally serve optical fiber-based networking applications. An optimization algorithm based on genetic algorithms was implemented for the complex nature of the work. FEM verifications reveal that the optimizing results show a good agreement with the simulated result.

Fabrication Comparison of the SCS-Based and SOI-Based Micromachining

The two different fabrications of the Micro-Electro-Mechanical Systems (MEMS) mirrors were compared: a single-crystal-silicon (SCS)-based micromachining and a silicon-on-insulator (SOI)- based micromachining. While the SOI parts had significantly smaller curved device appearance, they were outperformed in most areas by the SCS parts. This was due primarily to the smaller stress factor in the device layer in the SOI parts compared to the polysilicon layer used in the SCS parts.

Comparisons of the Straight Torsion Beam and Folded Torsion Beam Designs for MEMS Micromirrors

The torsion beam design for the micromirrors has an important effect on electrostatic behavior. We investigated three torsion beam designs and determined their effect on electrostatic characteristics as well as resonant frequency. The first design is straight torsion beam, which is the simplest and most commonly used. The second and third designs, add different folded structure to improve the performance. The results suggest that the folded-beam design has a significant effect on actuation performance. The most effective design had a driving voltage approximately one half of that for the simplest design, and the effect on resonant frequency is slightly more modest but still impressive.

Monolithically Integrated MEMS Optical Device with Switching and Attenuating Function

In this paper, a monolithically integrated device composed of optical switch (OS) and variable optical attenuator (VOA) is described. The device shows more functionality and more compactness in the all optical networks. Besides the advantage of wide attenuation range, its fabrication is simple and reliable. In our laboratory, a monolithically integrated optical device has been fabricated and setup for investigation. Experimental results have shown that the proposed approaches improve the compositive performance.