Deformable MEMS grating for wide tunability and high operating speed

Tormen, M.; Peter, Yves-Alain; Niedermann, Philippe; Hoogerwerf, A.; Stanley, R. P.

doi:10.1088/1464-4258/8/7/s07

Cited by 30 publications

(15 citation statements)

References 6 publications

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“…A specific optical MEMS device, a tunable grating 8,9 , has been adopted as a test vehicle to analyze the transient behavior of two failure mechanisms; first, the transient behavior during ESD events, then the failure of combdrive structures under shock and vibration during normal actuation conditions. The knowledge of transient behavior can be used to improve the device design and its resistance to failures.…”

Section: Introductionmentioning

confidence: 99%

ESD testing and combdrive snap-in in a MEMS tunable grating under shock and vibration

et al. 2011

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This work describes a method for tracking the dynamics of electrostatic discharge (ESD) sensitive MEMS structures during ESD events, as well as a model for determining the reduced combdrive snap-in voltage under vibration and shock. We describe our ESD test setup, based on the human body model, and optimized for high impedance devices. A brief description of the MEMS tunable grating, the test structure used here, and its operation is followed by results of the measured complex device dynamics during ESD events. The device fails at a voltage up to four times higher than that required to bring the parts into contact. We then present a model for the snap-in of combfingers under shock and vibration. We combine the results of the analytical model for combdrive snap-in developed here with a shock response model to compute the critical shock acceleration conditions that can result in combdrive snap-in as a function of the operating voltage. We discuss the validity regimes for the combdrive snap-in model and show how restricting the operation voltage below the snap-in voltage is not a sufficient criterion to ensure reliable operation especially in environments with large disturbances.

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Section: Introductionmentioning

confidence: 99%

ESD testing and combdrive snap-in in a MEMS tunable grating under shock and vibration

et al. 2011

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“…This is higher than what can be obtained with standard MEMS silicon-based approaches (see e.g. [30,31]). It is is also higher than other published results on DEA-based tunable gratings due to the use of the original replication process based on a water-soluble master.…”

Section: Tunable Grating In Open and Closed Loop Modementioning

confidence: 73%

Self-sensing dielectric elastomer actuators in closed-loop operation

Rosset

O’Brien

Gisby

et al. 2013

Smart Mater. Struct.

128

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Because of their large output strain, dielectric elastomer actuators (DEAs) have been proposed for tunable optics applications such as tunable gratings. However, the inherent viscoelastic drift of these actuators is an important drawback and closed-loop operation of DEAs is a prerequisite for any accurate real-world application. In this paper, we show how capacitive self-sensing can be used to drive a DEA in closed-loop without the need for any external sensor. The method has been demonstrated on a DEA tunable grating based on a VHB acrylic and silicone membrane. The results show that the widely used VHB presents a time-dependent drift between the capacitance of the electrodes and their strain. The silicone-based grating does not exhibit such a drift, and its strain can be stabilized by regulating the capacitance of the device to a constant value. We also report on an new fabrication method for thin deformable gratings based on replication on a water-soluble master and a 27% change in the grating period has been obtained on a VHB-based device. Abstract. Because of their large output strain, dielectric elastomer actuators (DEAs) have been proposed for tunable optics applications such as tunable gratings. However, the inherent viscoelastic drift of these actuators is an important drawback and closed-loop operation of DEAs is a prerequisite for any accurate real-world application. In this paper, we show how capacitive self-sensing can be used to drive a DEA in closed-loop without the need for any external sensor. The method has been demonstrated on a DEA tunable grating based on a VHB acrylic and silicone membrane. The results show that the widely used VHB presents a time-dependent drift between the capacitance of the electrodes and their strain. The silicone-based grating does not exhibit such a drift, and its strain can be stabilized by regulating the capacitance of the device to a constant value. We also report on an new fabrication method for thin deformable gratings based on replication on a water-soluble master and 27% change in the grating period has been obtained on a VHB-based device. Reference

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“…The tunable grating, similar to devices reported earlier [22,23], was fabricated by the CSEM (Neuchatel, Switzerland) and consists of three main functional parts: optical grating (approximately 1 mm × 1 mm), comb-drives to apply a tunable force, and suspension springs for the grating and the comb-drives (see figure 5). The grating fingers are connected to each other through folded beam structures and the central fingers are anchored to the substrate to ensure uniform expansion in both halves of the grating.…”

Section: Device Design Fabrication and Working Principlementioning

confidence: 99%

Vibration and shock reliability of MEMS: modeling and experimental validation

Sundaram

Tormen

Timotijević

et al. 2011

J. Micromech. Microeng.

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A methodology to predict shock and vibration levels that could lead to the failure of MEMS devices is reported as a function of vibration frequency and shock pulse duration. A combined experimental-analytical approach is developed, maintaining the simplicity and insightfulness of analytical methods without compromising on the accuracy characteristic of experimental methods. The minimum frequency-dependent acceleration that will lead to surfaces coming into contact, for vibration or shock inputs, is determined based on measured mode shapes, damping, resonant frequencies, and an analysis of failure modes, thus defining a safe operating region, without requiring shock or vibration testing. This critical acceleration for failure is a strong function of the drive voltage, and the safe operating region is predicted for transport (unbiased) and operation (biased condition). The model was experimentally validated for over-damped and under-damped modes of a comb-drive-driven silicon-on-insulator-based tunable grating. In-plane and out-of-plane vibration (up to 65 g) and shock (up to 6000 g) tests were performed for biased and unbiased conditions, and very good agreement was found between predicted and observed critical accelerations.

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Deformable MEMS grating for wide tunability and high operating speed

Cited by 30 publications

References 6 publications

ESD testing and combdrive snap-in in a MEMS tunable grating under shock and vibration

ESD testing and combdrive snap-in in a MEMS tunable grating under shock and vibration

Self-sensing dielectric elastomer actuators in closed-loop operation

Vibration and shock reliability of MEMS: modeling and experimental validation

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