A bi-axial vacuum-packaged piezoelectric MEMS mirror for smart headlights

Senger, Frank; Albers, Jörg; Hofmann, Ulrich; Piechotta, G.; Giese, Thorsten; Heinrich, Felix; Wantoch, Thomas von; Gu-Stoppel, Shanshan

doi:10.1117/12.2542802

Cited by 14 publications

(17 citation statements)

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“…In the last decade, different approaches to micro electromechanical (MEMS) mirrors have been pursued, mainly depending on the actuation system. Piezoelectric [ 1 ], capacitive [ 2 ], magnetic [ 3 , 4 ], and thermomechanical [ 5 ] actuation mirrors were developed, and their use was demonstrated in a plethora of applications.…”

Section: Introductionmentioning

confidence: 99%

High Frequency MEMS Capacitive Mirror for Space Applications

et al. 2023

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Free space optics laser communication using modulating retroreflectors (MR) is a challenging application for an active mirror, due to the high frequencies (>100 kHz) required to enable sufficient data transfer. Micro Electromechanical (MEMS) mirrors are a promising option for high-frequency applications, given the very small moving mass typical of such devices. Capacitive MEMS mirrors are presented here for free space communications, based on a novel fabrication sequence that introduces a single-layer thin film aluminum mirror structure with an underlying silicon oxide sacrificial layer. The use of aluminum instead of gold as a mirror layer diminishes the heating generated by the absorption of the sun’s radiation once the mirrors exit the earth’s atmosphere. Thanks to the novel fabrication sequence, the presented mirror devices have a full range actuation voltage of less than 40 V, and a high operational frequency with an eigenfrequency above 2 MHz. The devices were manufactured and characterized, and their main parameters were obtained from experimental data combined with finite element analysis, thus enabling future design optimization of the reported MEMS technology. By optical characterization of the far field diffraction pattern, good mirror performance was demonstrated.

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Section: Introductionmentioning

confidence: 99%

High Frequency MEMS Capacitive Mirror for Space Applications

et al. 2023

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“…Design-flexibility, device-compactness, low operation voltages, and the large field-of-view make piezoelectricallydriven microelectromechanical systems (MEMS) optical scanners highly attractive for the application in various miniaturized systems for projection or threedimensional sensing. [1][2][3][4][5] Recently, great progress has been made in the development of MEMS-based picoprojector systems to be prospectively implemented in augmented reality (AR) glasses for the consumer market. [6][7][8] However in the maritime context, MEMS-based AR glasses on lab-status 9 or commercially available state-of-the-art augmented-reality glasses often still possess an inconvenient size and weight considering its application for all-day usage, as it would be mandatory on a ship´s bridge.…”

Section: Introductionmentioning

confidence: 99%

“…1 This made the individual tuning of the two modes very challenging and led to artificial pincushion distortions in the projection image. 3 In the framework of this paper, a resonant, gimbal-less biaxial MEMS-scanner design is presented, which possesses remarkable flexibility to tailor the rotational movements independently. Here, the focus of the design-optimization study is on the improvement of the frequency ratio in order to achieve high fill factors and frame rates for the Lissajous projection.…”

Section: Introductionmentioning

confidence: 99%

Efficient piezoelectric gimbal-less MEMS-mirror with large design flexibility

Wysocki

Ratzmann

Schütt

et al. 2023

MOEMS and Miniaturized Systems XXII

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Biaxial resonant MEMS-scanners are considered as promising core-device in state-of-the-art imaging and projection systems due to their compactness, the large field-of-view, high speed, and comparably low power consumption. However, the usage in three-dimensional LIDAR modules or projectors for industrial applications is often limited by non-optimal Lissajous-scanning patterns. To achieve dense and spatially uniform Lissajous-trajectories, a suitable frequency ratio of the two oscillation modes is essential. In previous works, the frequency ratio was either maximized or minimized, which often led either to mechanical fragility or undesirable coupling of the two normal modes. For solving the abovementioned problems, a piezoelectrically-driven biaxial MEMS-scanner exhibiting large design flexibility, enabling the individual tailoring of the two orthogonal rotational oscillation-modes and Lissajous-patterns with large fill factor, was developed. This design freedom and decoupling of two axes motions are achieved by a gimbal-less design with individual actuator systems for the two oscillatory axes. Driven by the CMOS-compatible piezoelectric Al(Sc)N, the Q-factor of the resonant mirror with large optical aperture of 5 mm is enhanced by hermetic wafer-level glass-encapsulation. A projection module, which combines the biaxial MEMS-scanner, an RGB-laser-beam combiner, and the electronics for both read-out and control, was developed in the frame of a funded research project (”MEMS-scanner-based laser projection system for maritime augmented reality”). The target of the project was the development of a smart window, in the sense of a MEMS-scanner-based laser projection system for maritime augmented reality, which offers the possibility to fade in safety-relevant information of navigation and ship sensors into the field-of-view of the bridge personnel on the ship’s bridge. Such projector is promising also for further applications in industry, for instance in 3D cameras.

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“…Riding on the shoulders of the MEMS fabrication technologies, various MEMS optical scanners have been developed. The common driving mechanisms of MEMS scanners include electrostatic actuation [11,12], electromagnetic actuation [13,14], electrothermal actuation [15,16], and piezoelectric actuation [17]. Many electrostatic micromirrors require undesirable high voltages that sometimes approach a hundred volts [18]; electrothermal actuation and electromagnetic actuation both lead to direct heating of the mirror, which can potentially change the mirror parameters such as the curvature; piezoelectric material is less popular in semiconductor fabrication business.…”

Section: Introductionmentioning

confidence: 99%

Low-Cost 3D-Printed Electromagnetically Driven Large-Area 1-DOF Optical Scanners

et al. 2022

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In this paper, we demonstrate 3D-printed 1-DOF (one torsional axis; 1 degree of freedom) optical scanners with large mirror areas (up to 20 × 20 mm2). Each device consists of an aluminum-coated square silicon substrate serving as the mirror, two miniature permanent magnets, an electromagnet, and a 3D-printed structure including the mirror frame, torsion springs, and base. One device can reach a static half optical scan angle of 14.8 deg., i.e., a full optical scan angle of 29.6 deg., at 12 VDC; this particular device exhibits a mechanical resonance frequency of 84 Hz. These scanners can be a potential, low-cost alternative to the expensive conventional galvanometer scanners.

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A bi-axial vacuum-packaged piezoelectric MEMS mirror for smart headlights

Cited by 14 publications

References 0 publications

High Frequency MEMS Capacitive Mirror for Space Applications

High Frequency MEMS Capacitive Mirror for Space Applications

Efficient piezoelectric gimbal-less MEMS-mirror with large design flexibility

Low-Cost 3D-Printed Electromagnetically Driven Large-Area 1-DOF Optical Scanners

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