Large Stroke Staggered Vertical Comb-Drive Actuator for the Application of a Millimeter-Wave Tunable Phase Shifter

Li, Yunjia; Psychogiou, Dimitra; Kühne, Stéphane; Hesselbarth, Jan; Hafner, Christian; Hierold, Christofer

doi:10.1109/jmems.2013.2252146

Cited by 19 publications

(18 citation statements)

References 37 publications

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“…This thin metallization with thickness of around 100 nm, has very small influence on the torsional stiffness of the SU-8 spring, as its width and thickness are only 33.3% and 0.6% of the SU-8 layer. Through calculation, the contribution of the metal layers to the total torsional stiffness is only 0.1% [12]. The low stiffness of SU-8 enables a large stroke while the reversed-T cross-section provides a high in-plane stability of the actuator.…”

Section: A the Actuator Devicementioning

confidence: 99%

“…The actuator device used in this study is an electrostatic vertical comb-drive actuator suspended by an SU-8 spring [12]. A schematic of the actuator can be seen in Fig.…”

Section: A the Actuator Devicementioning

confidence: 99%

“…The torsional stiffness of the SU-8 spring can be extracted from the resonance frequency of the torsional vibration mode by [12]:…”

Section: A the Actuator Devicementioning

confidence: 99%

“…Nevertheless, according the authors' best knowledge, the torsional viscoelastic behavior of the SU- 8 has not yet been studied, despite the focus on torsional applications. In our previous work, the torsional creeping behavior of SU-8 spring was reported but not studied in detail [12]. In addition, it requires a long-term deflection stability under constant load when the SU-8 is used as a torsional spring.…”

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confidence: 99%

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SU-8 as a Torsional Spring: Viscoelastic Creeping and Closed Loop Control

Hierold

2015

J. Microelectromech. Syst.

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The torsional viscoelastic creeping and recovery of an SU-8 spring is reported by studying the deflection angle variation of a vertical comb-drive actuator suspended by an SU-8 spring at three different stress levels. A maximum creep of 0.43°(corresponding to a relative change of strain of 5.7%) is observed under a constant stress of 8.3 MPa in 1 h (V = 22.7 V). A capacitive readout circuit is designed to sense the torsional deflection of the comb-drive actuator. The circuit is capable of actuating and sensing the capacitance change by the same combdrives with a resolution of 0.03°(corresponding to a capacitance resolution of 0.05 pF). The readout capacitance is then used as the input variable for a proportional-integral (PI) controller in order to eliminate the time and load dependent drift by creeping of the SU-8 spring. The PI controller is tuned by the Ziegler-Nichols method and has a settling time of ∼2.3 s for the output. Compared with the open loop deflection of 0.43°, the closed-loop deflection is reduced by a factor of 7 down to 0.06°. This controller error is prominent at high actuation voltages, and is attributed to the actuator's lateral and vertical crosssensitivity. [2014-0124]

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Section: A the Actuator Devicementioning

confidence: 99%

“…The actuator device used in this study is an electrostatic vertical comb-drive actuator suspended by an SU-8 spring [12]. A schematic of the actuator can be seen in Fig.…”

Section: A the Actuator Devicementioning

confidence: 99%

“…The torsional stiffness of the SU-8 spring can be extracted from the resonance frequency of the torsional vibration mode by [12]:…”

Section: A the Actuator Devicementioning

confidence: 99%

mentioning

confidence: 99%

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SU-8 as a Torsional Spring: Viscoelastic Creeping and Closed Loop Control

Hierold

2015

J. Microelectromech. Syst.

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“…For this type of actuator a frequency tuning scheme has also been shown [17] by mechanically increasing the torsional spring stiffness using a chevron actuator. SVC actuators have also been achieved by using bulk micro-machining of a stack of silicon wafers requiring precise alignment between the individual wafers [18].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Properties of Angular Vertical Comb-Drive Scanning Micromirrors With Electrothermally Controlled Variable Offset

Bauer¹,

Uttamchandani

2014

J. Microelectromech. Syst.

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This paper presents the investigation of a variable angular vertical comb-drive (AVC) actuated MEMS scanning micromirror, focusing on the influence of the initial comb offset on the dynamic scan characteristics. Continuous control of the fixed comb initial vertical offset is achieved using an electrothermal actuator integrated in the AVC. Electro-thermomechanical simulations and experiments of the AVC structure show good agreement, with the initial vertical offset of the fixed comb reducing theoretically from 10.8 µm (0 mW to actuator) to 6.0 µm (500 mW to actuator) and experimentally from 10.4 µm (0 mW to actuator) to 4.9 µm (510 mW to actuator). Experimentally, a change of the initial vertical comb-offset from 10.4 µm to 4.9 µm leads to a reduction of the measured dynamic total optical scan angle (TOSA) from 27°to 19°for 100 V ac actuation. In addition, a mechanically assisted deflection of the AVC actuators to achieve an almost in-plane comb configuration further reduces the measured dynamic TOSA to about 3°. The overall device behavior is modeled using a hybrid simulation approach combining FEM analysis of the AVC capacitance with an analytical solution of the motion equation of the scanner. The analysis show good agreement, with the experimentally measured characteristics; overall showing an increased TOSA with higher initial comb offsets.[2013-0344] IndexTerms-Angular vertical comb-drive (AVC) actuators, scanning micromirrors, electrothermal microactuators, electrostatic force actuators.

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Organic Resonant MEMS Devices

Schmid

2015

Advanced Micro and Nanosystems

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Large Stroke Staggered Vertical Comb-Drive Actuator for the Application of a Millimeter-Wave Tunable Phase Shifter

Cited by 19 publications

References 37 publications

SU-8 as a Torsional Spring: Viscoelastic Creeping and Closed Loop Control

SU-8 as a Torsional Spring: Viscoelastic Creeping and Closed Loop Control

Dynamic Properties of Angular Vertical Comb-Drive Scanning Micromirrors With Electrothermally Controlled Variable Offset

Organic Resonant MEMS Devices

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