Design and Development of a Double-Bridge Micromirror With Bending and Twisting Cantilevers for Multiobject Spectroscopy
TL;DR: In this article, a double-bridge electrostatically actuated micromirror for multi-object spectroscopy (MOS) was proposed. But the two-axis symmetric rotation mechanism is achieved by bending and twisting action of the suspended cantilevers.
Abstract: This article presents the design, development, and characterization of a double-bridge electrostatically actuated micromirror for multiobject spectroscopy (MOS). The proposed structure is an improvement over single-bridge micromirrors in terms of aperture size, pull-in voltage, degrees of freedom, and fill factor. The two-axis symmetric rotation mechanism of the proposed micromirror is achieved by bending and twisting action of the suspended cantilevers which is contrary to the twisting cantilevers of a conventional one-axis torsional micromirror. The placement of anchor and cantilevers under the mirror plate results in a high fill factor when arranged in a 2-D array. The analytical modeling, design optimization, and static and dynamic analysis are done using finite-element method (FEM) in Coventorware. An optimized design is fabricated using a simple approach of surface micromachining and electroplating. For a micromirror of size $200\,\,\mu \text{m}\,\,\times 200\,\,\mu \text{m}$ and the actuation gap of $2.5~\mu \text{m}$ , the device exhibits a tilt angle of 1.5° at a pull-in voltage of 23.1 V, a switching time of $38~\mu \text{s}$ , and the resonance frequency of 35.23 kHz. A ${3} \times {3}$ array of the micromirror is demonstrated with a fill factor of more than 95%. The deflection range can be increased by simply increasing the thickness of the sacrificial layer and without any major process modification.
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TL;DR: In this paper , a self-sensing actuating composite structure for constructing an electrostatic torsional actuator is proposed, which is capable of self-adjusting pull-in titling angle of micro-actuator based on strain gradient theory with size dependency and damage.
TL;DR: In this paper, an electrostatic micromirror for space-based multiobject spectroscopy (MOS) is presented, in which the deflection is achieved by a combination of bending and twisting cantilevers.
Abstract: This article presents the analytical modeling, design, and performance analysis of an electrostatic micromirror for space-based Multiobject Spectroscopy (MOS). The micromirror under investigation is a double-bridge design with hidden cantilevers architecture in which the deflection is achieved by a combination of bending and twisting cantilevers. A simple closed-form solution of pull-in voltage and deflection is obtained using the parallel-plate capacitor model that assumes micromirror deflection dominated by bending cantilevers due to electrostatic actuation. The design optimization is done to achieve a micromirror of size $200\,\,\mu \text{m}\,\,\times 200\,\,\mu \text{m}$ , deflection $2.5~\mu \text{m}$ , pull-in voltage smaller than 25 V, and a shock survival capacity of at least 10 000 g. The static and dynamic behavior of the optimized design is obtained using the analytical model and compared with the finite-element method (FEM) and characterization results and found to be in close agreement. The micromirror exhibits an analytical pull-in voltage near the FEM and measured pull-in voltage with a deviation of 5% and 0.9%, respectively. The analytical resonance frequency is also closer to simulation and measurement results with a deviation of 4.66% and 2.58%, respectively. The analytical switching time is also very close to the FEM results, with a deviation of 28%. The analytical model and the simple approach of design optimization using tuning parameters presented in the article can be used to design the micromirror according to desired specifications.
TL;DR: In this article , a piezoelectrically driven deformable reflective micromirror is designed and fabricated by physical vapor deposition, UV lithography, eutectic bonding, mechanical cutting, deep reactive ion etching (RIE), and other processes to complete the preparation of micromIRrors.
Abstract: As the core component of the adaptive optics system, the deformable mirror is developing towards miniaturization and integration through the combination of MEMS technology. In this paper, based on the inverse piezoelectric effect of piezoelectric materials, a piezoelectrically driven deformable reflective micromirror is designed and fabricated by physical vapor deposition, UV lithography, eutectic bonding, mechanical cutting, deep reactive ion etching (RIE) and other processes to complete the preparation of micromirrors. The problems related to the eutectic bonding process of PZT and Si in the fabrication of micromirrors are emphatically studied through tensile experiments. The micromirror was tested with a laser interferometer. The test results showed that the prepared micromirror could achieve a maximum deformation of 0.6 μm in the positive direction and 1.7 μm in the negative direction when a voltage of ±1.5 kV was applied.
TL;DR: In this paper , Liu et al. provided an active control method to avoid the pull-in instability of an electrostatically driven circular micromirror by applying voltage on a torsional piezoelectric composite structure.
Abstract: Cited as: Liu, M., Chen, Y., Cheng, W., Chen, S., Yu, T., Yang, W. Controllable electromechanical stability of a torsional micromirror actuator with piezoelectric composite structure under capillary force. Capillarity, 2022, 5(3): 51-64. https://doi.org/10.46690/capi.2022.03.02 Abstract: Various types of micro/nano functional devices are being widely designed as optical switches, micro scanners, micromirrors and other core optical devices. The continuing miniaturization of the functional devices makes the size dependence of electromechanical property significant in micro/nano scale due to the sharp increase of surface interactions such as capillary force from liquid bridge, van der Waals and Casimir forces from quantum fluctuations. The surface interactions can cause the pull-in instability, adhesion between parts, and even failure of device. This work provides an active control method to avoid the pull-in instability of an electrostatically driven circular micromirror by applying voltage on a torsional piezoelectric composite structure. The influences of the three types are compared of dispersion forces on the electromechanical stability of the micromirror actuator. A comprehensive electromechanical model of a torsional piezoelectric beam was established to numerically investigate the electromechanical coupling of the micromirror. The results show that the influence of capillary force on the stability of the micromirror is as significant as van der Waals force and Casimir force. By introducing piezoelectric nanoplates into the laminated torsional structure, the micromirror stability can be controlled based on the piezoelectric effect of the torsional piezoelectric composite structure. This work can contribute to the structural optimization design and manufacture of micromirror systems.
References
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TL;DR: In this article, a high-resolution projection micro-stereolithography (PμSL) process by using the Digital Micromirror Device (DMD™, Texas Instruments) as a dynamic mask is presented.
Abstract: We present in this paper the development of a high-resolution projection micro-stereolithography (PμSL) process by using the Digital Micromirror Device (DMD™, Texas Instruments) as a dynamic mask. This unique technology provides a parallel fabrication of complex three-dimensional (3D) microstructures used for micro electro-mechanical systems (MEMS). Based on the understanding of underlying mechanisms, a process model has been developed with all critical parameters obtained from the experimental measurement. By coupling the experimental measurement and the process model, the photon-induced curing behavior of the resin has been quantitatively studied. The role of UV doping has been thereafter justified, as it can effectively reduce the curing depth without compromising the chemical property of the resin. The fabrication of complex 3D microstructures, such as matrix, and micro-spring array, with the smallest feature of 0.6 μm, has been demonstrated.
760 citations
01 Aug 1998
TL;DR: The digital display engine (DDE) as discussed by the authors is based on a single DMD device having array dimensions of 800/spl times/600 elements, illuminated by a metal halide arc lamp through a compact optics train.
Abstract: A period of rapid growth and change in the display industry has recently given rise to many new display technologies. One such technology, the Digital Micromirror Device/sup TM/ (DMD), developed at Texas Instruments, represents a unique application of microelectromechanical systems to the area of projection displays. In this paper, we describe a representative example of a DMD-based projection display engine, the digital display engine (DDE). The DDE is based on a single-DMD device having array dimensions of 800/spl times/600 elements, illuminated by a metal halide arc lamp through a compact optics train. The engine is designed for portable and fixed conference-room graphics and video display applications, and many design decisions were made to tailor the engine for its intended venue. The design of the projection engine optics and electronics is discussed, along with the basic operation, manufacture, and reliability of the DMD itself.
642 citations
"Design and Development of a Double-..." refers background in this paper
...M ICROELECTROMECHANICAL system (MEMS)based micromirror devices have made rapid developments since its first use as a light projection system [1]....
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IBM1
TL;DR: In this paper, the authors describe fabrication procedures for constructing thin, electrostatically deflectable SiO 2 membranes on a silicon wafer in a very controllable manner, and three examples of typical applications for the micromechanical structures are discussed.
Abstract: New fabrication procedures ate described for constructing thin, electrostatically deflectable SiO 2 membranes on a silicon wafer in a very controllable manner. Performance parameters of these membranes are analyzed and three examples of typical applications for the micromechanical structures are discussed: a light modulator array, a micromechanical voltage-controlled switch, and the measurement of the mechanical properties of thin insulating films unconstrained by the substrate. Since the lifetimes of the membranes can be very long (>1010cycles), their dimensions very small (8.3 µm long, 950 A thick have been demonstrated), and the fabrication technique is simple and versatile, the potential applicability of such devices seems promising.
481 citations
IBM1
TL;DR: This device is extremely simple to make and operate, has operational characteristics comparable to commercial magnetically driven high-frequency scanners, and has exhibited a promising reliability.
Abstract: Conventional batch photolithography and thin film techniques are employed to fabricate an electrostatically driven torsional scanning mirror from single-crystal silicon. This device is extremely simple to make and operate, has operational characteristics comparable to commercial magnetically driven high-frequency scanners, and has exhibited a promising reliability.
306 citations
"Design and Development of a Double-..." refers background in this paper
...3016624 maskless lithography [4], optical scanning [5], optical cross-connects [6], endoscopic imaging [7], and optical...
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TL;DR: In this article, the free-space micromachined optical switches (FS-MOS) demonstrated in this paper represent a means of filling this network need by combining the advantages of free-rotating hinged micromirrors with the virtues of integrated optics.
Abstract: Optical crossconnects with large port counts are fast becoming critical components for high-capacity optical transport networks. The free-space micromachined optical switches (FS-MOS) demonstrated in this letter represent a means of filling this network need by combining the advantages of free-space interconnection with the virtues of integrated optics. Featuring free-rotating hinged micromirrors, the switch overcomes the common drawback of mechanical-type switches, namely long switching time. Measurements have revealed switching times less than 700 /spl mu/s, crosstalk less than -60 dB, extinction ratio greater than 60 dB, negligible polarization-dependent loss, and excellent bit-error-rate (BER) performance.
269 citations