Dynamic actuation of polyimide V-groove joints by electrical heating

Ebefors, Thorbjörn; Kälvesten, Edvard; Stemme, G.

doi:10.1016/s0924-4247(97)01769-x

Cited by 35 publications

(35 citation statements)

References 4 publications

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“…In the most sophisticated demonstrations to date, the parts have carried optical components arranged as miniature freespace optical systems on a chip, including laser collimators [15]- [19], tunable filters [20], [21], and beam scanners activated by electrostatic actuators [22], [23], thermal bimorphs [24], [25], and thermally rotated polymer-filled joints [26]. Much of this work is described in a recent review of microoptomechanical systems [27].…”

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confidence: 99%

Surface tension powered self-assembly of 3-D micro-optomechanical structures

Syms

1999

J. Microelectromech. Syst.

110

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Abstract-A new surface micromachining process for surface tension powered self-assembly of silicon-based microstructures is described. Mechanical parts are formed from bonded silicon-oninsulator material and rotated out-of-plane by melting photoresist pads at low temperature. Simple mechanisms that allow accurate control of the final angle are introduced and used to construct fixed 45 mirrors and scanning mirror assemblies. [435]

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mentioning

confidence: 99%

Surface tension powered self-assembly of 3-D micro-optomechanical structures

Syms

1999

J. Microelectromech. Syst.

110

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“…Deflections >100 μm and forces >100 mN can be provided at an energy density higher than of electrostatic actuators. Electrothermal actuators can be fabricated from metal [1,2], silicon [3,4] or polymer materials such as epoxide, polyimide [5] or polyether ether ketone (PEEK) [6]. Applications of miniaturized thermal actuators are the positioning of optical fibers [7], micro grippers [3,[8][9][10], relays [11,12], Radio Frequency (RF) switches [13] or miniaturized drives [14].…”

Section: Introductionmentioning

confidence: 99%

SU-8 Electrothermal Actuators: Optimization of Fabrication and Excitation for Long-Term Use

et al. 2014

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Abstract:In this paper we examine the suitability of SU-8 2000 as a construction material for electrothermal actuators and the actuator stability for long-term operation. The fabrication of SU-8 was optimized for mechanical and thermal stability. Samples with different softbake duration, exposure dose and postbake temperature were evaluated using Fourier-Transform IR-spectroscopy and dynamic-mechanical analysis. The exposure dose and postbake temperature proved to have a strong influence on the cross-linking and the glass transition temperature. A final hardbake levels the effects of the process history. A high degree of crosslinking, a low drop of the dynamic modulus over temperature (30%) up to the glass transition temperature 100-140 °C were achieved for SU-8 with an exposure dose of 1500 mJ/cm², a postbake temperature of 95 °C and hardbake of 240 °C. Electrothermal actuators proved to be stable until the end of the experiment after 2400 duty cycles. Actuator deflections up to 55 μm were measured (actuator length: 4 mm) for input powers up to 160 mW and a maximum operating temperature of 120 °C. Higher temperatures led to permanent deformations and failure. An offset drift of up to 20% occurs during actuation, but converges after a burn-in phase of about two hours. OPEN ACCESSMicromachines 2014, 5 1311

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“…Although these methods enable dynamic adjustment of the rotation angle, they require complex mechanisms and the use of many wires for actuation. Self-assembly methods using external magnetic fields (6) , the surface tension of liquids (7) and thermal shrinkage of V-groove polyimide joints (8) have also been developed. The structures assembled using external magnetic fields and the surface tension of liquids are mechanically interlocked making dynamic actuation after assembly is difficult.…”

Section: Introductionmentioning

confidence: 99%

“…The structures assembled using external magnetic fields and the surface tension of liquids are mechanically interlocked making dynamic actuation after assembly is difficult. Structures with V-groove polyimide joints (8) are assembled using thermal shrinkage of polyimide by curing below 400°C. The static bending angle can be controlled by varying the curing temperature and have achieved 35° per V-groove.…”

Section: Introductionmentioning

confidence: 99%

Self- Assembly and Magnetic Actuation of Three Dimensional Micro Hinged Mechanisms

et al. 2007

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This paper describes self-assembly of hinged mechanisms using thermal shrinkage of polyimide and actuation of the assembled mechanisms using external magnetic field. A schematic illustration of the 3D mechanism with the polyimide hinge is shown in Fig. 1. The proposed self-assembly method allows the hinged mechanism to be rotated out of the wafer plane by only heating and to stay bent without any interlocking mechanisms. The bending angle of the polyimide hinge depends on heating time, heating temperature, and length of the hinge. In these parameters, the heating time was found to be the most suitable for the control of the bending angle. The bending angle increases almost linearly with increasing heating time, and varies over a wide range from 30º to 170º.Using this self-assembly technique, a microcube was assembled from a planar structure that consisted of five free plates and a fixed plate connected by the polyimide hinges. It was cured at 500ºC for 90 minutes, which is the condition obtained experimentally to achieve 90º rotation of each plate. Fig. 2 shows SEM photographs of self-assembled microcubes. Many cubes were assembled simultaneously on the same wafer.Actuation of the structure after self-assembly will greatly expand the possibility of the application of 3D hinged structure. So, experiments in actuation of the self-assembled structure using external magnetic field were performed. A self-assembled structure that consisted of Ni plates and polyimide hinges were put in the magnetic field controlled by a solenoid coil to actuate the hinges from the assembled position. Fig. 3 (a) shows a CCD image of the hinged-structure after the polyimide hinges were heated at 500ºC for 50 minutes. The tilt angle of the plate adjacent to the fixed plate (θ 0 ) is 23º. When the magnetic field of 38.5kA/m was applied, the hinge was deformed elastically and the tilt angle θ became 60º. Furthermore the structure could be also vibrated by applying the alternating magnetic field.These results demonstrate that the proposed assembly process and actuation are promising techniques for batch fabrication and wireless actuation of truly 3-D micromechanisms. Non-memberThis paper describes three-dimensional (3D) micro structures fabricated using a simple self-assembly process involving the thermal shrinkage of polyimide. The proposed method enables hinged structures automatically to be rotated out of the wafer plane and to remain bent without the need to use any interlocking mechanisms. The hinged structures were fabricated using surface micromachining techniques involving heating in a furnace. An increase in the bending angle due to the shrinkage of polyimide was observed with increasing heating time, heating temperature, and length of the polyimide hinge. Of these three parameters, the heating time was found to be the most suitable for control of the bending angle. Microcubes were fabricated by this method and the self-assembly process was successfully visualized using a CCD camera. Furthermore, the hinged structures were actuated...

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Dynamic actuation of polyimide V-groove joints by electrical heating

Cited by 35 publications

References 4 publications

Surface tension powered self-assembly of 3-D micro-optomechanical structures

Surface tension powered self-assembly of 3-D micro-optomechanical structures

SU-8 Electrothermal Actuators: Optimization of Fabrication and Excitation for Long-Term Use

Self- Assembly and Magnetic Actuation of Three Dimensional Micro Hinged Mechanisms

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